[dev.fuzz] all: merge master (b0fa2f5) into dev.fuzz
Merge List:
+ 2021-09-20 b0fa2f5b09 cmd/compile: fix ExampleInfo output
Change-Id: Iccc726a8925082688faa94d07b829a5705f58dda
diff --git a/api/except.txt b/api/except.txt
index 14fe778..b9972c1 100644
--- a/api/except.txt
+++ b/api/except.txt
@@ -492,6 +492,7 @@
pkg syscall (windows-amd64), type CertSimpleChain struct, TrustListInfo uintptr
pkg syscall (windows-amd64), type RawSockaddrAny struct, Pad [96]int8
pkg testing, func MainStart(func(string, string) (bool, error), []InternalTest, []InternalBenchmark, []InternalExample) *M
+pkg testing, func MainStart(testDeps, []InternalTest, []InternalBenchmark, []InternalExample) *M
pkg testing, func RegisterCover(Cover)
pkg text/scanner, const GoTokens = 1012
pkg text/template/parse, type DotNode bool
diff --git a/api/next.txt b/api/next.txt
index 3eb7f3f..b1b9c1d 100644
--- a/api/next.txt
+++ b/api/next.txt
@@ -106,3 +106,39 @@
pkg syscall (windows-386), func WSASendtoInet6(Handle, *WSABuf, uint32, *uint32, uint32, SockaddrInet6, *Overlapped, *uint8) error
pkg syscall (windows-amd64), func WSASendtoInet4(Handle, *WSABuf, uint32, *uint32, uint32, SockaddrInet4, *Overlapped, *uint8) error
pkg syscall (windows-amd64), func WSASendtoInet6(Handle, *WSABuf, uint32, *uint32, uint32, SockaddrInet6, *Overlapped, *uint8) error
+pkg testing, func Fuzz(func(*F)) FuzzResult
+pkg testing, func MainStart(testDeps, []InternalTest, []InternalBenchmark, []InternalFuzzTarget, []InternalExample) *M
+pkg testing, func RunFuzzTargets(func(string, string) (bool, error), []InternalFuzzTarget) bool
+pkg testing, func RunFuzzing(func(string, string) (bool, error), []InternalFuzzTarget) bool
+pkg testing, method (*B) Setenv(string, string)
+pkg testing, method (*F) Add(...interface{})
+pkg testing, method (*F) Cleanup(func())
+pkg testing, method (*F) Error(...interface{})
+pkg testing, method (*F) Errorf(string, ...interface{})
+pkg testing, method (*F) Fail()
+pkg testing, method (*F) FailNow()
+pkg testing, method (*F) Failed() bool
+pkg testing, method (*F) Fatal(...interface{})
+pkg testing, method (*F) Fatalf(string, ...interface{})
+pkg testing, method (*F) Fuzz(interface{})
+pkg testing, method (*F) Helper()
+pkg testing, method (*F) Log(...interface{})
+pkg testing, method (*F) Logf(string, ...interface{})
+pkg testing, method (*F) Name() string
+pkg testing, method (*F) Setenv(string, string)
+pkg testing, method (*F) Skip(...interface{})
+pkg testing, method (*F) SkipNow()
+pkg testing, method (*F) Skipf(string, ...interface{})
+pkg testing, method (*F) Skipped() bool
+pkg testing, method (*F) TempDir() string
+pkg testing, method (*T) Setenv(string, string)
+pkg testing, method (FuzzResult) String() string
+pkg testing, type F struct
+pkg testing, type FuzzResult struct
+pkg testing, type FuzzResult struct, Crasher entry
+pkg testing, type FuzzResult struct, Error error
+pkg testing, type FuzzResult struct, N int
+pkg testing, type FuzzResult struct, T time.Duration
+pkg testing, type InternalFuzzTarget struct
+pkg testing, type InternalFuzzTarget struct, Fn func(*F)
+pkg testing, type InternalFuzzTarget struct, Name string
diff --git a/codereview.cfg b/codereview.cfg
index 77a74f1..bed9bcf 100644
--- a/codereview.cfg
+++ b/codereview.cfg
@@ -1 +1,2 @@
-branch: master
+branch: dev.fuzz
+parent-branch: master
\ No newline at end of file
diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go
index 9753ebb..7452269 100644
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@@ -53,6 +53,7 @@
// private configuration for downloading non-public code
// testflag testing flags
// testfunc testing functions
+// fuzz fuzzing
// vcs controlling version control with GOVCS
//
// Use "go help <topic>" for more information about that topic.
@@ -292,6 +293,8 @@
// download cache, including unpacked source code of versioned
// dependencies.
//
+// The -fuzzcache flag causes clean to remove values used for fuzz testing.
+//
// For more about build flags, see 'go help build'.
//
// For more about specifying packages, see 'go help packages'.
@@ -1488,8 +1491,8 @@
//
// 'Go test' recompiles each package along with any files with names matching
// the file pattern "*_test.go".
-// These additional files can contain test functions, benchmark functions, and
-// example functions. See 'go help testfunc' for more.
+// These additional files can contain test functions, benchmark functions, fuzz
+// targets and example functions. See 'go help testfunc' for more.
// Each listed package causes the execution of a separate test binary.
// Files whose names begin with "_" (including "_test.go") or "." are ignored.
//
@@ -1559,6 +1562,8 @@
// in no time at all,so a successful package test result will be cached and
// reused regardless of -timeout setting.
//
+// Run 'go help fuzz' for details around how the go command handles fuzz targets.
+//
// In addition to the build flags, the flags handled by 'go test' itself are:
//
// -args
@@ -2728,7 +2733,8 @@
// (for example, -benchtime 100x).
//
// -count n
-// Run each test and benchmark n times (default 1).
+// Run each test, benchmark, and fuzz targets' seed corpora n times
+// (default 1).
// If -cpu is set, run n times for each GOMAXPROCS value.
// Examples are always run once.
//
@@ -2757,36 +2763,55 @@
// Sets -cover.
//
// -cpu 1,2,4
-// Specify a list of GOMAXPROCS values for which the tests or
-// benchmarks should be executed. The default is the current value
+// Specify a list of GOMAXPROCS values for which the tests, benchmarks or
+// fuzz targets should be executed. The default is the current value
// of GOMAXPROCS.
//
// -failfast
// Do not start new tests after the first test failure.
//
+// -fuzz name
+// Run the fuzz target with the given regexp. Must match exactly one fuzz
+// target. This is an experimental feature.
+//
+// -fuzztime t
+// Run enough iterations of the fuzz test to take t, specified as a
+// time.Duration (for example, -fuzztime 1h30s). The default is to run
+// forever.
+// The special syntax Nx means to run the fuzz test N times
+// (for example, -fuzztime 100x).
+//
// -json
// Log verbose output and test results in JSON. This presents the
// same information as the -v flag in a machine-readable format.
//
+// -keepfuzzing
+// Keep running the fuzz target if a crasher is found.
+//
// -list regexp
-// List tests, benchmarks, or examples matching the regular expression.
-// No tests, benchmarks or examples will be run. This will only
-// list top-level tests. No subtest or subbenchmarks will be shown.
+// List tests, benchmarks, fuzz targets, or examples matching the regular
+// expression. No tests, benchmarks, fuzz targets, or examples will be run.
+// This will only list top-level tests. No subtest or subbenchmarks will be
+// shown.
//
// -parallel n
-// Allow parallel execution of test functions that call t.Parallel.
+// Allow parallel execution of test functions that call t.Parallel, and
+// f.Fuzz functions that call t.Parallel when running the seed corpus.
// The value of this flag is the maximum number of tests to run
-// simultaneously; by default, it is set to the value of GOMAXPROCS.
+// simultaneously. While fuzzing, the value of this flag is the
+// maximum number of workers to run the fuzz function simultaneously,
+// regardless of whether t.Parallel has been called; by default, it is set
+// to the value of GOMAXPROCS.
// Note that -parallel only applies within a single test binary.
// The 'go test' command may run tests for different packages
// in parallel as well, according to the setting of the -p flag
// (see 'go help build').
//
// -run regexp
-// Run only those tests and examples matching the regular expression.
-// For tests, the regular expression is split by unbracketed slash (/)
-// characters into a sequence of regular expressions, and each part
-// of a test's identifier must match the corresponding element in
+// Run only those tests, examples, and fuzz targets matching the regular
+// expression. For tests, the regular expression is split by unbracketed
+// slash (/) characters into a sequence of regular expressions, and each
+// part of a test's identifier must match the corresponding element in
// the sequence, if any. Note that possible parents of matches are
// run too, so that -run=X/Y matches and runs and reports the result
// of all tests matching X, even those without sub-tests matching Y,
@@ -2953,6 +2978,10 @@
//
// func BenchmarkXxx(b *testing.B) { ... }
//
+// A fuzz target is one named FuzzXxx and should have the signature,
+//
+// func FuzzXxx(f *testing.F) { ... }
+//
// An example function is similar to a test function but, instead of using
// *testing.T to report success or failure, prints output to os.Stdout.
// If the last comment in the function starts with "Output:" then the output
@@ -2992,11 +3021,30 @@
//
// The entire test file is presented as the example when it contains a single
// example function, at least one other function, type, variable, or constant
-// declaration, and no test or benchmark functions.
+// declaration, and no fuzz targets or test or benchmark functions.
//
// See the documentation of the testing package for more information.
//
//
+// Fuzzing
+//
+// By default, go test will build and run the fuzz targets using the target's seed
+// corpus only. Any generated corpora in $GOCACHE that were previously written by
+// the fuzzing engine will not be run by default.
+//
+// When -fuzz is set, the binary will be instrumented for coverage. After all
+// tests, examples, benchmark functions, and the seed corpora for all fuzz targets
+// have been run, go test will begin to fuzz the specified fuzz target.
+// Note that this feature is experimental.
+//
+// -run can be used for testing a single seed corpus entry for a fuzz target. The
+// regular expression value of -run can be in the form $target/$name, where $target
+// is the name of the fuzz target, and $name is the name of the file (ignoring file
+// extensions) to run. For example, -run=FuzzFoo/497b6f87.
+//
+// See https://golang.org/s/draft-fuzzing-design for more details.
+//
+//
// Controlling version control with GOVCS
//
// The 'go get' command can run version control commands like git
diff --git a/src/cmd/go/internal/cache/cache.go b/src/cmd/go/internal/cache/cache.go
index d592d70..596f22e8 100644
--- a/src/cmd/go/internal/cache/cache.go
+++ b/src/cmd/go/internal/cache/cache.go
@@ -533,3 +533,13 @@
return nil
}
+
+// FuzzDir returns a subdirectory within the cache for storing fuzzing data.
+// The subdirectory may not exist.
+//
+// This directory is managed by the internal/fuzz package. Files in this
+// directory aren't removed by the 'go clean -cache' command or by Trim.
+// They may be removed with 'go clean -fuzzcache'.
+func (c *Cache) FuzzDir() string {
+ return filepath.Join(c.dir, "fuzz")
+}
diff --git a/src/cmd/go/internal/cfg/cfg.go b/src/cmd/go/internal/cfg/cfg.go
index 5f4465e..dd0e8cb 100644
--- a/src/cmd/go/internal/cfg/cfg.go
+++ b/src/cmd/go/internal/cfg/cfg.go
@@ -60,6 +60,10 @@
func defaultContext() build.Context {
ctxt := build.Default
+
+ // TODO(#47037): remove this tag before merging to master.
+ ctxt.BuildTags = []string{"gofuzzbeta"}
+
ctxt.JoinPath = filepath.Join // back door to say "do not use go command"
ctxt.GOROOT = findGOROOT()
diff --git a/src/cmd/go/internal/clean/clean.go b/src/cmd/go/internal/clean/clean.go
index 1089211..518473c 100644
--- a/src/cmd/go/internal/clean/clean.go
+++ b/src/cmd/go/internal/clean/clean.go
@@ -75,6 +75,8 @@
download cache, including unpacked source code of versioned
dependencies.
+The -fuzzcache flag causes clean to remove values used for fuzz testing.
+
For more about build flags, see 'go help build'.
For more about specifying packages, see 'go help packages'.
@@ -85,6 +87,7 @@
cleanI bool // clean -i flag
cleanR bool // clean -r flag
cleanCache bool // clean -cache flag
+ cleanFuzzcache bool // clean -fuzzcache flag
cleanModcache bool // clean -modcache flag
cleanTestcache bool // clean -testcache flag
)
@@ -96,6 +99,7 @@
CmdClean.Flag.BoolVar(&cleanI, "i", false, "")
CmdClean.Flag.BoolVar(&cleanR, "r", false, "")
CmdClean.Flag.BoolVar(&cleanCache, "cache", false, "")
+ CmdClean.Flag.BoolVar(&cleanFuzzcache, "fuzzcache", false, "")
CmdClean.Flag.BoolVar(&cleanModcache, "modcache", false, "")
CmdClean.Flag.BoolVar(&cleanTestcache, "testcache", false, "")
@@ -112,7 +116,7 @@
// or no other target (such as a cache) was requested to be cleaned.
cleanPkg := len(args) > 0 || cleanI || cleanR
if (!modload.Enabled() || modload.HasModRoot()) &&
- !cleanCache && !cleanModcache && !cleanTestcache {
+ !cleanCache && !cleanModcache && !cleanTestcache && !cleanFuzzcache {
cleanPkg = true
}
@@ -206,6 +210,18 @@
}
}
}
+
+ if cleanFuzzcache {
+ fuzzDir := cache.Default().FuzzDir()
+ if cfg.BuildN || cfg.BuildX {
+ b.Showcmd("", "rm -rf %s", fuzzDir)
+ }
+ if !cfg.BuildN {
+ if err := os.RemoveAll(fuzzDir); err != nil {
+ base.Errorf("go clean -fuzzcache: %v", err)
+ }
+ }
+ }
}
var cleaned = map[*load.Package]bool{}
diff --git a/src/cmd/go/internal/load/flag.go b/src/cmd/go/internal/load/flag.go
index 4e0cb5b..2467052 100644
--- a/src/cmd/go/internal/load/flag.go
+++ b/src/cmd/go/internal/load/flag.go
@@ -22,8 +22,9 @@
// that allows specifying different effective flags for different packages.
// See 'go help build' for more details about per-package flags.
type PerPackageFlag struct {
- present bool
- values []ppfValue
+ present bool
+ values []ppfValue
+ seenPackages map[*Package]bool // the packages for which the flags have already been set
}
// A ppfValue is a single <pattern>=<flags> per-package flag value.
diff --git a/src/cmd/go/internal/load/pkg.go b/src/cmd/go/internal/load/pkg.go
index 4013330..317053d 100644
--- a/src/cmd/go/internal/load/pkg.go
+++ b/src/cmd/go/internal/load/pkg.go
@@ -2630,10 +2630,20 @@
func setToolFlags(pkgs ...*Package) {
for _, p := range PackageList(pkgs) {
- p.Internal.Asmflags = BuildAsmflags.For(p)
- p.Internal.Gcflags = BuildGcflags.For(p)
- p.Internal.Ldflags = BuildLdflags.For(p)
- p.Internal.Gccgoflags = BuildGccgoflags.For(p)
+ appendFlags(p, &p.Internal.Asmflags, &BuildAsmflags)
+ appendFlags(p, &p.Internal.Gcflags, &BuildGcflags)
+ appendFlags(p, &p.Internal.Ldflags, &BuildLdflags)
+ appendFlags(p, &p.Internal.Gccgoflags, &BuildGccgoflags)
+ }
+}
+
+func appendFlags(p *Package, flags *[]string, packageFlag *PerPackageFlag) {
+ if !packageFlag.seenPackages[p] {
+ if packageFlag.seenPackages == nil {
+ packageFlag.seenPackages = make(map[*Package]bool)
+ }
+ packageFlag.seenPackages[p] = true
+ *flags = append(*flags, packageFlag.For(p)...)
}
}
diff --git a/src/cmd/go/internal/load/test.go b/src/cmd/go/internal/load/test.go
index 42eefe3..da6d1cb 100644
--- a/src/cmd/go/internal/load/test.go
+++ b/src/cmd/go/internal/load/test.go
@@ -555,6 +555,7 @@
type testFuncs struct {
Tests []testFunc
Benchmarks []testFunc
+ FuzzTargets []testFunc
Examples []testFunc
TestMain *testFunc
Package *Package
@@ -653,6 +654,13 @@
}
t.Benchmarks = append(t.Benchmarks, testFunc{pkg, name, "", false})
*doImport, *seen = true, true
+ case isTest(name, "Fuzz"):
+ err := checkTestFunc(n, "F")
+ if err != nil {
+ return err
+ }
+ t.FuzzTargets = append(t.FuzzTargets, testFunc{pkg, name, "", false})
+ *doImport, *seen = true, true
}
}
ex := doc.Examples(f)
@@ -716,6 +724,12 @@
{{end}}
}
+var fuzzTargets = []testing.InternalFuzzTarget{
+{{range .FuzzTargets}}
+ {"{{.Name}}", {{.Package}}.{{.Name}}},
+{{end}}
+}
+
var examples = []testing.InternalExample{
{{range .Examples}}
{"{{.Name}}", {{.Package}}.{{.Name}}, {{.Output | printf "%q"}}, {{.Unordered}}},
@@ -774,7 +788,7 @@
CoveredPackages: {{printf "%q" .Covered}},
})
{{end}}
- m := testing.MainStart(testdeps.TestDeps{}, tests, benchmarks, examples)
+ m := testing.MainStart(testdeps.TestDeps{}, tests, benchmarks, fuzzTargets, examples)
{{with .TestMain}}
{{.Package}}.{{.Name}}(m)
os.Exit(int(reflect.ValueOf(m).Elem().FieldByName("exitCode").Int()))
diff --git a/src/cmd/go/internal/test/flagdefs.go b/src/cmd/go/internal/test/flagdefs.go
index 37ac81c..3148074 100644
--- a/src/cmd/go/internal/test/flagdefs.go
+++ b/src/cmd/go/internal/test/flagdefs.go
@@ -19,6 +19,9 @@
"cpu": true,
"cpuprofile": true,
"failfast": true,
+ "fuzz": true,
+ "fuzzminimizetime": true,
+ "fuzztime": true,
"list": true,
"memprofile": true,
"memprofilerate": true,
diff --git a/src/cmd/go/internal/test/flagdefs_test.go b/src/cmd/go/internal/test/flagdefs_test.go
index ab5440b..f238fc7 100644
--- a/src/cmd/go/internal/test/flagdefs_test.go
+++ b/src/cmd/go/internal/test/flagdefs_test.go
@@ -17,7 +17,7 @@
}
name := strings.TrimPrefix(f.Name, "test.")
switch name {
- case "testlogfile", "paniconexit0":
+ case "testlogfile", "paniconexit0", "fuzzcachedir", "fuzzworker":
// These are internal flags.
default:
if !passFlagToTest[name] {
diff --git a/src/cmd/go/internal/test/genflags.go b/src/cmd/go/internal/test/genflags.go
index 9277de7..645aae6 100644
--- a/src/cmd/go/internal/test/genflags.go
+++ b/src/cmd/go/internal/test/genflags.go
@@ -64,7 +64,7 @@
name := strings.TrimPrefix(f.Name, "test.")
switch name {
- case "testlogfile", "paniconexit0":
+ case "testlogfile", "paniconexit0", "fuzzcachedir", "fuzzworker":
// These flags are only for use by cmd/go.
default:
names = append(names, name)
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index 198afbf..8f5d57e 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -61,8 +61,8 @@
'Go test' recompiles each package along with any files with names matching
the file pattern "*_test.go".
-These additional files can contain test functions, benchmark functions, and
-example functions. See 'go help testfunc' for more.
+These additional files can contain test functions, benchmark functions, fuzz
+targets and example functions. See 'go help testfunc' for more.
Each listed package causes the execution of a separate test binary.
Files whose names begin with "_" (including "_test.go") or "." are ignored.
@@ -132,6 +132,8 @@
in no time at all,so a successful package test result will be cached and
reused regardless of -timeout setting.
+Run 'go help fuzz' for details around how the go command handles fuzz targets.
+
In addition to the build flags, the flags handled by 'go test' itself are:
-args
@@ -208,7 +210,8 @@
(for example, -benchtime 100x).
-count n
- Run each test and benchmark n times (default 1).
+ Run each test, benchmark, and fuzz targets' seed corpora n times
+ (default 1).
If -cpu is set, run n times for each GOMAXPROCS value.
Examples are always run once.
@@ -237,36 +240,55 @@
Sets -cover.
-cpu 1,2,4
- Specify a list of GOMAXPROCS values for which the tests or
- benchmarks should be executed. The default is the current value
+ Specify a list of GOMAXPROCS values for which the tests, benchmarks or
+ fuzz targets should be executed. The default is the current value
of GOMAXPROCS.
-failfast
Do not start new tests after the first test failure.
+ -fuzz name
+ Run the fuzz target with the given regexp. Must match exactly one fuzz
+ target. This is an experimental feature.
+
+ -fuzztime t
+ Run enough iterations of the fuzz test to take t, specified as a
+ time.Duration (for example, -fuzztime 1h30s). The default is to run
+ forever.
+ The special syntax Nx means to run the fuzz test N times
+ (for example, -fuzztime 100x).
+
-json
Log verbose output and test results in JSON. This presents the
same information as the -v flag in a machine-readable format.
+ -keepfuzzing
+ Keep running the fuzz target if a crasher is found.
+
-list regexp
- List tests, benchmarks, or examples matching the regular expression.
- No tests, benchmarks or examples will be run. This will only
- list top-level tests. No subtest or subbenchmarks will be shown.
+ List tests, benchmarks, fuzz targets, or examples matching the regular
+ expression. No tests, benchmarks, fuzz targets, or examples will be run.
+ This will only list top-level tests. No subtest or subbenchmarks will be
+ shown.
-parallel n
- Allow parallel execution of test functions that call t.Parallel.
+ Allow parallel execution of test functions that call t.Parallel, and
+ f.Fuzz functions that call t.Parallel when running the seed corpus.
The value of this flag is the maximum number of tests to run
- simultaneously; by default, it is set to the value of GOMAXPROCS.
+ simultaneously. While fuzzing, the value of this flag is the
+ maximum number of workers to run the fuzz function simultaneously,
+ regardless of whether t.Parallel has been called; by default, it is set
+ to the value of GOMAXPROCS.
Note that -parallel only applies within a single test binary.
The 'go test' command may run tests for different packages
in parallel as well, according to the setting of the -p flag
(see 'go help build').
-run regexp
- Run only those tests and examples matching the regular expression.
- For tests, the regular expression is split by unbracketed slash (/)
- characters into a sequence of regular expressions, and each part
- of a test's identifier must match the corresponding element in
+ Run only those tests, examples, and fuzz targets matching the regular
+ expression. For tests, the regular expression is split by unbracketed
+ slash (/) characters into a sequence of regular expressions, and each
+ part of a test's identifier must match the corresponding element in
the sequence, if any. Note that possible parents of matches are
run too, so that -run=X/Y matches and runs and reports the result
of all tests matching X, even those without sub-tests matching Y,
@@ -436,6 +458,10 @@
func BenchmarkXxx(b *testing.B) { ... }
+A fuzz target is one named FuzzXxx and should have the signature,
+
+ func FuzzXxx(f *testing.F) { ... }
+
An example function is similar to a test function but, instead of using
*testing.T to report success or failure, prints output to os.Stdout.
If the last comment in the function starts with "Output:" then the output
@@ -475,12 +501,34 @@
The entire test file is presented as the example when it contains a single
example function, at least one other function, type, variable, or constant
-declaration, and no test or benchmark functions.
+declaration, and no fuzz targets or test or benchmark functions.
See the documentation of the testing package for more information.
`,
}
+var HelpFuzz = &base.Command{
+ UsageLine: "fuzz",
+ Short: "fuzzing",
+ Long: `
+By default, go test will build and run the fuzz targets using the target's seed
+corpus only. Any generated corpora in $GOCACHE that were previously written by
+the fuzzing engine will not be run by default.
+
+When -fuzz is set, the binary will be instrumented for coverage. After all
+tests, examples, benchmark functions, and the seed corpora for all fuzz targets
+have been run, go test will begin to fuzz the specified fuzz target.
+Note that this feature is experimental.
+
+-run can be used for testing a single seed corpus entry for a fuzz target. The
+regular expression value of -run can be in the form $target/$name, where $target
+is the name of the fuzz target, and $name is the name of the file (ignoring file
+extensions) to run. For example, -run=FuzzFoo/497b6f87.
+
+See https://golang.org/s/draft-fuzzing-design for more details.
+`,
+}
+
var (
testBench string // -bench flag
testC bool // -c flag
@@ -489,6 +537,7 @@
testCoverPaths []string // -coverpkg flag
testCoverPkgs []*load.Package // -coverpkg flag
testCoverProfile string // -coverprofile flag
+ testFuzz string // -fuzz flag
testJSON bool // -json flag
testList string // -list flag
testO string // -o flag
@@ -622,6 +671,9 @@
if testO != "" && len(pkgs) != 1 {
base.Fatalf("cannot use -o flag with multiple packages")
}
+ if testFuzz != "" && len(pkgs) != 1 {
+ base.Fatalf("cannot use -fuzz flag with multiple packages")
+ }
if testProfile() != "" && len(pkgs) != 1 {
base.Fatalf("cannot use %s flag with multiple packages", testProfile())
}
@@ -632,7 +684,9 @@
// to that timeout plus one minute. This is a backup alarm in case
// the test wedges with a goroutine spinning and its background
// timer does not get a chance to fire.
- if testTimeout > 0 {
+ // Don't set this if fuzzing, since it should be able to run
+ // indefinitely.
+ if testTimeout > 0 && testFuzz == "" {
testKillTimeout = testTimeout + 1*time.Minute
}
@@ -782,6 +836,32 @@
}
}
+ // Inform the compiler that it should instrument the binary at
+ // build-time when fuzzing is enabled.
+ fuzzFlags := work.FuzzInstrumentFlags()
+ if testFuzz != "" && fuzzFlags != nil {
+ // Don't instrument packages which may affect coverage guidance but are
+ // unlikely to be useful. Most of these are used by the testing or
+ // internal/fuzz concurrently with fuzzing.
+ var fuzzNoInstrument = map[string]bool{
+ "context": true,
+ "internal/fuzz": true,
+ "reflect": true,
+ "runtime": true,
+ "sync": true,
+ "sync/atomic": true,
+ "syscall": true,
+ "testing": true,
+ "time": true,
+ }
+ for _, p := range load.TestPackageList(ctx, pkgOpts, pkgs) {
+ if fuzzNoInstrument[p.ImportPath] {
+ continue
+ }
+ p.Internal.Gcflags = append(p.Internal.Gcflags, fuzzFlags...)
+ }
+ }
+
// Prepare build + run + print actions for all packages being tested.
for _, p := range pkgs {
// sync/atomic import is inserted by the cover tool. See #18486
@@ -1087,6 +1167,8 @@
}
var noTestsToRun = []byte("\ntesting: warning: no tests to run\n")
+var noTargetsToFuzz = []byte("\ntesting: warning: no targets to fuzz\n")
+var tooManyTargetsToFuzz = []byte("\ntesting: warning: -fuzz matches more than one target, won't fuzz\n")
type runCache struct {
disableCache bool // cache should be disabled for this run
@@ -1134,10 +1216,10 @@
}
var buf bytes.Buffer
- if len(pkgArgs) == 0 || (testBench != "") {
+ if len(pkgArgs) == 0 || testBench != "" || testFuzz != "" {
// Stream test output (no buffering) when no package has
// been given on the command line (implicit current directory)
- // or when benchmarking.
+ // or when benchmarking or fuzzing.
// No change to stdout.
} else {
// If we're only running a single package under test or if parallelism is
@@ -1190,7 +1272,12 @@
testlogArg = []string{"-test.testlogfile=" + a.Objdir + "testlog.txt"}
}
panicArg := "-test.paniconexit0"
- args := str.StringList(execCmd, a.Deps[0].BuiltTarget(), testlogArg, panicArg, testArgs)
+ fuzzArg := []string{}
+ if testFuzz != "" {
+ fuzzCacheDir := filepath.Join(cache.Default().FuzzDir(), a.Package.ImportPath)
+ fuzzArg = []string{"-test.fuzzcachedir=" + fuzzCacheDir}
+ }
+ args := str.StringList(execCmd, a.Deps[0].BuiltTarget(), testlogArg, panicArg, fuzzArg, testArgs)
if testCoverProfile != "" {
// Write coverage to temporary profile, for merging later.
@@ -1283,6 +1370,12 @@
if bytes.HasPrefix(out, noTestsToRun[1:]) || bytes.Contains(out, noTestsToRun) {
norun = " [no tests to run]"
}
+ if bytes.HasPrefix(out, noTargetsToFuzz[1:]) || bytes.Contains(out, noTargetsToFuzz) {
+ norun = " [no targets to fuzz]"
+ }
+ if bytes.HasPrefix(out, tooManyTargetsToFuzz[1:]) || bytes.Contains(out, tooManyTargetsToFuzz) {
+ norun = " [will not fuzz, -fuzz matches more than one target]"
+ }
fmt.Fprintf(cmd.Stdout, "ok \t%s\t%s%s%s\n", a.Package.ImportPath, t, coveragePercentage(out), norun)
c.saveOutput(a)
} else {
diff --git a/src/cmd/go/internal/test/testflag.go b/src/cmd/go/internal/test/testflag.go
index e0a3e01..cb35438 100644
--- a/src/cmd/go/internal/test/testflag.go
+++ b/src/cmd/go/internal/test/testflag.go
@@ -57,6 +57,7 @@
cf.String("cpu", "", "")
cf.StringVar(&testCPUProfile, "cpuprofile", "", "")
cf.Bool("failfast", false, "")
+ cf.StringVar(&testFuzz, "fuzz", "", "")
cf.StringVar(&testList, "list", "", "")
cf.StringVar(&testMemProfile, "memprofile", "", "")
cf.String("memprofilerate", "", "")
@@ -67,6 +68,8 @@
cf.String("run", "", "")
cf.Bool("short", false, "")
cf.DurationVar(&testTimeout, "timeout", 10*time.Minute, "")
+ cf.String("fuzztime", "", "")
+ cf.String("fuzzminimizetime", "", "")
cf.StringVar(&testTrace, "trace", "", "")
cf.BoolVar(&testV, "v", false, "")
cf.Var(&testShuffle, "shuffle", "")
diff --git a/src/cmd/go/internal/work/init.go b/src/cmd/go/internal/work/init.go
index 7aa8dfe..2a605e7 100644
--- a/src/cmd/go/internal/work/init.go
+++ b/src/cmd/go/internal/work/init.go
@@ -60,6 +60,14 @@
}
}
+func FuzzInstrumentFlags() []string {
+ if cfg.Goarch != "amd64" && cfg.Goarch != "arm64" {
+ // Instrumentation is only supported on 64-bit architectures.
+ return nil
+ }
+ return []string{"-d=libfuzzer"}
+}
+
func instrumentInit() {
if !cfg.BuildRace && !cfg.BuildMSan {
return
diff --git a/src/cmd/go/main.go b/src/cmd/go/main.go
index 16361e0..11ff750 100644
--- a/src/cmd/go/main.go
+++ b/src/cmd/go/main.go
@@ -80,6 +80,7 @@
modfetch.HelpPrivate,
test.HelpTestflag,
test.HelpTestfunc,
+ test.HelpFuzz,
modget.HelpVCS,
}
}
diff --git a/src/cmd/go/testdata/script/test_fuzz.txt b/src/cmd/go/testdata/script/test_fuzz.txt
new file mode 100644
index 0000000..b1a02f4
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz.txt
@@ -0,0 +1,442 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+# Test that running a fuzz target that returns without failing or calling
+# f.Fuzz fails and causes a non-zero exit status.
+! go test noop_fuzz_test.go
+! stdout ^ok
+stdout FAIL
+
+# Test that fuzzing a fuzz target that returns without failing or calling
+# f.Fuzz fails and causes a non-zero exit status.
+! go test -fuzz=Fuzz -fuzztime=1x noop_fuzz_test.go
+! stdout ^ok
+stdout FAIL
+
+# Test that calling f.Error in a fuzz target causes a non-zero exit status.
+! go test -fuzz=Fuzz -fuzztime=1x error_fuzz_test.go
+! stdout ^ok
+stdout FAIL
+
+# Test that calling f.Fatal in a fuzz target causes a non-zero exit status.
+! go test fatal_fuzz_test.go
+! stdout ^ok
+stdout FAIL
+
+# Test that successful test exits cleanly.
+go test success_fuzz_test.go
+stdout ^ok
+! stdout FAIL
+
+# Test that successful fuzzing exits cleanly.
+go test -fuzz=Fuzz -fuzztime=1x success_fuzz_test.go
+stdout ok
+! stdout FAIL
+
+# Test that calling f.Fatal while fuzzing causes a non-zero exit status.
+! go test -fuzz=Fuzz -fuzztime=1x fatal_fuzz_test.go
+! stdout ^ok
+stdout FAIL
+
+# Test error with seed corpus in f.Fuzz
+! go test -run FuzzError fuzz_add_test.go
+! stdout ^ok
+stdout FAIL
+stdout 'error here'
+
+[short] stop
+
+# Test that calling panic(nil) in a fuzz target causes a non-zero exit status.
+! go test panic_fuzz_test.go
+! stdout ^ok
+stdout FAIL
+
+# Test that skipped test exits cleanly.
+go test skipped_fuzz_test.go
+stdout ok
+! stdout FAIL
+
+# Test that f.Fatal within f.Fuzz panics
+! go test fatal_fuzz_fn_fuzz_test.go
+! stdout ^ok
+! stdout 'fatal here'
+stdout FAIL
+stdout 'f.Fuzz function'
+
+# Test that f.Error within f.Fuzz panics
+! go test error_fuzz_fn_fuzz_test.go
+! stdout ^ok
+! stdout 'error here'
+stdout FAIL
+stdout 'f.Fuzz function'
+
+# Test that f.Skip within f.Fuzz panics
+! go test skip_fuzz_fn_fuzz_test.go
+! stdout ^ok
+! stdout 'skip here'
+stdout FAIL
+stdout 'f.Fuzz function'
+
+# Test that a call to f.Fatal after the Fuzz func is never executed.
+go test fatal_after_fuzz_func_fuzz_test.go
+stdout ok
+! stdout FAIL
+
+# Test that missing *T in f.Fuzz causes a non-zero exit status.
+! go test incomplete_fuzz_call_fuzz_test.go
+! stdout ^ok
+stdout FAIL
+
+# Test that a panic in the Cleanup func is executed.
+! go test cleanup_fuzz_test.go
+! stdout ^ok
+stdout FAIL
+stdout 'failed some precondition'
+
+# Test success with seed corpus in f.Fuzz
+go test -run FuzzPass fuzz_add_test.go
+stdout ok
+! stdout FAIL
+! stdout 'off by one error'
+
+# Test fatal with seed corpus in f.Fuzz
+! go test -run FuzzFatal fuzz_add_test.go
+! stdout ^ok
+stdout FAIL
+stdout 'fatal here'
+
+# Test panic with seed corpus in f.Fuzz
+! go test -run FuzzPanic fuzz_add_test.go
+! stdout ^ok
+stdout FAIL
+stdout 'off by one error'
+
+# Test panic(nil) with seed corpus in f.Fuzz
+! go test -run FuzzNilPanic fuzz_add_test.go
+! stdout ^ok
+stdout FAIL
+
+# Test panic with unsupported seed corpus
+! go test -run FuzzUnsupported fuzz_add_test.go
+! stdout ^ok
+stdout FAIL
+
+# Test panic with different number of args to f.Add
+! go test -run FuzzAddDifferentNumber fuzz_add_test.go
+! stdout ^ok
+stdout FAIL
+
+# Test panic with different type of args to f.Add
+! go test -run FuzzAddDifferentType fuzz_add_test.go
+! stdout ^ok
+stdout FAIL
+
+# Test that the wrong type given with f.Add will fail.
+! go test -run FuzzWrongType fuzz_add_test.go
+! stdout ^ok
+stdout FAIL
+
+# Test fatal with testdata seed corpus
+! go test -run FuzzFail corpustesting/fuzz_testdata_corpus_test.go
+! stdout ^ok
+stdout FAIL
+stdout 'fatal here'
+
+# Test pass with testdata seed corpus
+go test -run FuzzPass corpustesting/fuzz_testdata_corpus_test.go
+stdout ok
+! stdout FAIL
+! stdout 'fatal here'
+
+# Test pass with testdata and f.Add seed corpus
+go test -run FuzzPassString corpustesting/fuzz_testdata_corpus_test.go
+stdout ok
+! stdout FAIL
+
+# Fuzzing pass with testdata and f.Add seed corpus (skip running tests first)
+go test -run=None -fuzz=FuzzPassString corpustesting/fuzz_testdata_corpus_test.go -fuzztime=10x
+stdout ok
+! stdout FAIL
+
+# Fuzzing pass with testdata and f.Add seed corpus
+go test -run=FuzzPassString -fuzz=FuzzPassString corpustesting/fuzz_testdata_corpus_test.go -fuzztime=10x
+stdout ok
+! stdout FAIL
+
+# Test panic with malformed seed corpus
+! go test -run FuzzFail corpustesting/fuzz_testdata_corpus_test.go
+! stdout ^ok
+stdout FAIL
+
+# Test pass with file in other nested testdata directory
+go test -run FuzzInNestedDir corpustesting/fuzz_testdata_corpus_test.go
+stdout ok
+! stdout FAIL
+! stdout 'fatal here'
+
+# Test fails with file containing wrong type
+! go test -run FuzzWrongType corpustesting/fuzz_testdata_corpus_test.go
+! stdout ^ok
+stdout FAIL
+
+-- noop_fuzz_test.go --
+package noop_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {}
+
+-- error_fuzz_test.go --
+package error_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Error("error in target")
+}
+
+-- fatal_fuzz_test.go --
+package fatal_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Fatal("fatal in target")
+}
+
+-- panic_fuzz_test.go --
+package panic_fuzz
+
+import "testing"
+
+func FuzzPanic(f *testing.F) {
+ panic(nil)
+}
+
+-- success_fuzz_test.go --
+package success_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Fuzz(func (*testing.T, []byte) {})
+}
+
+-- skipped_fuzz_test.go --
+package skipped_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Skip()
+}
+
+-- fatal_fuzz_fn_fuzz_test.go --
+package fatal_fuzz_fn_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Add([]byte("aa"))
+ f.Fuzz(func(t *testing.T, b []byte) {
+ f.Fatal("fatal here")
+ })
+}
+
+-- error_fuzz_fn_fuzz_test.go --
+package error_fuzz_fn_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Add([]byte("aa"))
+ f.Fuzz(func(t *testing.T, b []byte) {
+ f.Error("error here")
+ })
+}
+
+-- skip_fuzz_fn_fuzz_test.go --
+package skip_fuzz_fn_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Add([]byte("aa"))
+ f.Fuzz(func(t *testing.T, b []byte) {
+ f.Skip("skip here")
+ })
+}
+
+-- fatal_after_fuzz_func_fuzz_test.go --
+package fatal_after_fuzz_func_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Fuzz(func(t *testing.T, b []byte) {
+ // no-op
+ })
+ f.Fatal("this shouldn't be called")
+}
+
+-- incomplete_fuzz_call_fuzz_test.go --
+package incomplete_fuzz_call_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Fuzz(func(b []byte) {
+ // this is missing *testing.T as the first param, so should panic
+ })
+}
+
+-- cleanup_fuzz_test.go --
+package cleanup_fuzz_test
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Cleanup(func() {
+ panic("failed some precondition")
+ })
+ f.Fuzz(func(t *testing.T, b []byte) {
+ // no-op
+ })
+}
+
+-- fuzz_add_test.go --
+package fuzz_add
+
+import "testing"
+
+func add(f *testing.F) {
+ f.Helper()
+ f.Add([]byte("123"))
+ f.Add([]byte("12345"))
+ f.Add([]byte(""))
+}
+
+func FuzzPass(f *testing.F) {
+ add(f)
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if len(b) == -1 {
+ t.Fatal("fatal here") // will not be executed
+ }
+ })
+}
+
+func FuzzError(f *testing.F) {
+ add(f)
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if len(b) == 3 {
+ t.Error("error here")
+ }
+ })
+}
+
+func FuzzFatal(f *testing.F) {
+ add(f)
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if len(b) == 0 {
+ t.Fatal("fatal here")
+ }
+ })
+}
+
+func FuzzPanic(f *testing.F) {
+ add(f)
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if len(b) == 5 {
+ panic("off by one error")
+ }
+ })
+}
+
+func FuzzNilPanic(f *testing.F) {
+ add(f)
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if len(b) == 3 {
+ panic(nil)
+ }
+ })
+}
+
+func FuzzUnsupported(f *testing.F) {
+ m := make(map[string]bool)
+ f.Add(m)
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+func FuzzAddDifferentNumber(f *testing.F) {
+ f.Add([]byte("a"))
+ f.Add([]byte("a"), []byte("b"))
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+func FuzzAddDifferentType(f *testing.F) {
+ f.Add(false)
+ f.Add(1234)
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+func FuzzWrongType(f *testing.F) {
+ f.Add("hello")
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+-- corpustesting/fuzz_testdata_corpus_test.go --
+package fuzz_testdata_corpus
+
+import "testing"
+
+func fuzzFn(f *testing.F) {
+ f.Helper()
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if string(b) == "12345" {
+ t.Fatal("fatal here")
+ }
+ })
+}
+
+func FuzzFail(f *testing.F) {
+ fuzzFn(f)
+}
+
+func FuzzPass(f *testing.F) {
+ fuzzFn(f)
+}
+
+func FuzzPassString(f *testing.F) {
+ f.Add("some seed corpus")
+ f.Fuzz(func(*testing.T, string) {})
+}
+
+func FuzzPanic(f *testing.F) {
+ f.Fuzz(func(t *testing.T, b []byte) {})
+}
+
+func FuzzInNestedDir(f *testing.F) {
+ f.Fuzz(func(t *testing.T, b []byte) {})
+}
+
+func FuzzWrongType(f *testing.F) {
+ f.Fuzz(func(t *testing.T, b []byte) {})
+}
+
+-- corpustesting/testdata/fuzz/FuzzFail/1 --
+go test fuzz v1
+[]byte("12345")
+-- corpustesting/testdata/fuzz/FuzzPass/1 --
+go test fuzz v1
+[]byte("00000")
+-- corpustesting/testdata/fuzz/FuzzPassString/1 --
+go test fuzz v1
+string("hello")
+-- corpustesting/testdata/fuzz/FuzzPanic/1 --
+malformed
+-- corpustesting/testdata/fuzz/FuzzInNestedDir/anotherdir/1 --
+go test fuzz v1
+[]byte("12345")
+-- corpustesting/testdata/fuzz/FuzzWrongType/1 --
+go test fuzz v1
+int("00000")
\ No newline at end of file
diff --git a/src/cmd/go/testdata/script/test_fuzz_cache.txt b/src/cmd/go/testdata/script/test_fuzz_cache.txt
new file mode 100644
index 0000000..10e4c29
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_cache.txt
@@ -0,0 +1,81 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+[short] skip
+env GOCACHE=$WORK/cache
+
+# Fuzz cache should not exist after a regular test run.
+go test .
+exists $GOCACHE
+! exists $GOCACHE/fuzz
+
+# Fuzzing should write interesting values to the cache.
+go test -fuzz=FuzzY -fuzztime=100x .
+go run ./contains_files $GOCACHE/fuzz/example.com/y/FuzzY
+
+# 'go clean -cache' should not delete the fuzz cache.
+go clean -cache
+exists $GOCACHE/fuzz
+
+# 'go clean -fuzzcache' should delete the fuzz cache but not the build cache.
+go list -f {{.Stale}} ./empty
+stdout true
+go install ./empty
+go list -f {{.Stale}} ./empty
+stdout false
+go clean -fuzzcache
+! exists $GOCACHE/fuzz
+go list -f {{.Stale}} ./empty
+stdout false
+
+-- go.mod --
+module example.com/y
+
+go 1.16
+-- y_test.go --
+package y
+
+import (
+ "io"
+ "testing"
+)
+
+func FuzzY(f *testing.F) {
+ f.Add([]byte("y"))
+ f.Fuzz(func(t *testing.T, b []byte) { Y(io.Discard, b) })
+}
+-- y.go --
+package y
+
+import (
+ "bytes"
+ "io"
+)
+
+func Y(w io.Writer, b []byte) {
+ if !bytes.Equal(b, []byte("y")) {
+ w.Write([]byte("not equal"))
+ }
+}
+-- empty/empty.go --
+package empty
+-- contains_files/contains_files.go --
+package main
+
+import (
+ "fmt"
+ "path/filepath"
+ "io/ioutil"
+ "os"
+)
+
+func main() {
+ infos, err := ioutil.ReadDir(filepath.Clean(os.Args[1]))
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ }
+ if len(infos) == 0 {
+ os.Exit(1)
+ }
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_chatty.txt b/src/cmd/go/testdata/script/test_fuzz_chatty.txt
new file mode 100644
index 0000000..9ebd480
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_chatty.txt
@@ -0,0 +1,106 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+[short] skip
+
+# Run chatty fuzz targets with an error.
+! go test -v chatty_error_fuzz_test.go
+! stdout '^ok'
+stdout 'FAIL'
+stdout 'error in target'
+
+# Run chatty fuzz targets with a fatal.
+! go test -v chatty_fatal_fuzz_test.go
+! stdout '^ok'
+stdout 'FAIL'
+stdout 'fatal in target'
+
+# Run chatty fuzz target with a panic
+! go test -v chatty_panic_fuzz_test.go
+! stdout ^ok
+stdout FAIL
+stdout 'this is bad'
+
+# Run skipped chatty fuzz targets.
+go test -v chatty_skipped_fuzz_test.go
+stdout ok
+stdout SKIP
+! stdout FAIL
+
+# Run successful chatty fuzz targets.
+go test -v chatty_fuzz_test.go
+stdout ok
+stdout PASS
+stdout 'all good here'
+! stdout FAIL
+
+# Fuzz successful chatty fuzz target that includes a separate unit test.
+go test -v chatty_with_test_fuzz_test.go -fuzz=Fuzz -fuzztime=1x
+stdout ok
+stdout PASS
+! stdout FAIL
+# TODO: It's currently the case that it's logged twice. Fix that, and change
+# this check to verify it.
+stdout 'all good here'
+# Verify that the unit test is only run once.
+! stdout '(?s)logged foo.*logged foo'
+
+-- chatty_error_fuzz_test.go --
+package chatty_error_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Error("error in target")
+}
+
+-- chatty_fatal_fuzz_test.go --
+package chatty_fatal_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Fatal("fatal in target")
+}
+
+-- chatty_panic_fuzz_test.go --
+package chatty_panic_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ panic("this is bad")
+}
+
+-- chatty_skipped_fuzz_test.go --
+package chatty_skipped_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Skip()
+}
+
+-- chatty_fuzz_test.go --
+package chatty_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Log("all good here")
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+-- chatty_with_test_fuzz_test.go --
+package chatty_with_test_fuzz
+
+import "testing"
+
+func TestFoo(t *testing.T) {
+ t.Log("logged foo")
+}
+
+func Fuzz(f *testing.F) {
+ f.Log("all good here")
+ f.Fuzz(func(*testing.T, []byte) {})
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_cleanup.txt b/src/cmd/go/testdata/script/test_fuzz_cleanup.txt
new file mode 100644
index 0000000..8862591
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_cleanup.txt
@@ -0,0 +1,67 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+[short] skip
+
+# Cleanup should run after F.Skip.
+go test -run=FuzzTargetSkip
+stdout cleanup
+
+# Cleanup should run after F.Fatal.
+! go test -run=FuzzTargetFatal
+stdout cleanup
+
+# Cleanup should run after an unexpected runtime.Goexit.
+! go test -run=FuzzTargetGoexit
+stdout cleanup
+
+# Cleanup should run after panic.
+! go test -run=FuzzTargetPanic
+stdout cleanup
+
+# Cleanup should run in fuzz function on seed corpus.
+go test -v -run=FuzzFunction
+stdout '(?s)inner.*outer'
+
+# TODO(jayconrod): test cleanup while fuzzing. For now, the worker process's
+# stdout and stderr is connected to the coordinator's, but it should eventually
+# be connected to os.DevNull, so we wouldn't see t.Log output.
+
+-- go.mod --
+module cleanup
+
+go 1.15
+-- cleanup_test.go --
+package cleanup
+
+import (
+ "runtime"
+ "testing"
+)
+
+func FuzzTargetSkip(f *testing.F) {
+ f.Cleanup(func() { f.Log("cleanup") })
+ f.Skip()
+}
+
+func FuzzTargetFatal(f *testing.F) {
+ f.Cleanup(func() { f.Log("cleanup") })
+ f.Fatal()
+}
+
+func FuzzTargetGoexit(f *testing.F) {
+ f.Cleanup(func() { f.Log("cleanup") })
+ runtime.Goexit()
+}
+
+func FuzzTargetPanic(f *testing.F) {
+ f.Cleanup(func() { f.Log("cleanup") })
+ panic("oh no")
+}
+
+func FuzzFunction(f *testing.F) {
+ f.Add([]byte{0})
+ f.Cleanup(func() { f.Log("outer") })
+ f.Fuzz(func(t *testing.T, b []byte) {
+ t.Cleanup(func() { t.Logf("inner") })
+ })
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_deadline.txt b/src/cmd/go/testdata/script/test_fuzz_deadline.txt
new file mode 100644
index 0000000..12f1054
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_deadline.txt
@@ -0,0 +1,37 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+[short] skip
+
+# The fuzz function should be able to detect whether -timeout
+# was set with T.Deadline. Note there is no F.Deadline, and
+# there is no timeout while fuzzing, even if -fuzztime is set.
+go test -run=FuzzDeadline -wantdeadline=true # -timeout defaults to 10m
+go test -run=FuzzDeadline -timeout=0 -wantdeadline=false
+! go test -run=FuzzDeadline -timeout=1s -wantdeadline=false
+go test -run=FuzzDeadline -timeout=1s -wantdeadline=true
+go test -fuzz=FuzzDeadline -timeout=0 -fuzztime=1s -wantdeadline=false
+go test -fuzz=FuzzDeadline -timeout=0 -fuzztime=100x -wantdeadline=false
+
+-- go.mod --
+module fuzz
+
+go 1.16
+-- fuzz_deadline_test.go --
+package fuzz_test
+
+import (
+ "flag"
+ "testing"
+)
+
+var wantDeadline = flag.Bool("wantdeadline", false, "whether the test should have a deadline")
+
+func FuzzDeadline(f *testing.F) {
+ f.Add("run once")
+ f.Fuzz(func (t *testing.T, _ string) {
+ if _, hasDeadline := t.Deadline(); hasDeadline != *wantDeadline {
+ t.Fatalf("function got %v; want %v", hasDeadline, *wantDeadline)
+ }
+ })
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_fuzztime.txt b/src/cmd/go/testdata/script/test_fuzz_fuzztime.txt
new file mode 100644
index 0000000..7d644b4
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_fuzztime.txt
@@ -0,0 +1,82 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+[short] skip
+
+# There are no seed values, so 'go test' should finish quickly.
+go test
+
+# Fuzzing should exit 0 after fuzztime, even if timeout is short.
+go test -timeout=10ms -fuzz=FuzzFast -fuzztime=5s
+
+# We should see the same behavior when invoking the test binary directly.
+go test -c
+exec ./fuzz.test$GOEXE -test.timeout=10ms -test.fuzz=FuzzFast -test.fuzztime=5s -test.parallel=1 -test.fuzzcachedir=$WORK/cache
+
+# Timeout should not cause inputs to be written as crashers.
+! exists testdata/fuzz
+
+# When we use fuzztime with an "x" suffix, it runs a specific number of times.
+# This fuzz function creates a file with a unique name ($pid.$count) on each run.
+# We count the files to find the number of runs.
+mkdir count
+env GOCACHE=$WORK/tmp
+go test -fuzz=FuzzCount -fuzztime=1000x -fuzzminimizetime=1x
+go run check_file_count.go 1000
+
+-- go.mod --
+module fuzz
+
+go 1.16
+-- fuzz_fast_test.go --
+package fuzz_test
+
+import "testing"
+
+func FuzzFast(f *testing.F) {
+ f.Fuzz(func (*testing.T, []byte) {})
+}
+-- fuzz_count_test.go --
+package fuzz
+
+import (
+ "fmt"
+ "os"
+ "testing"
+)
+
+func FuzzCount(f *testing.F) {
+ pid := os.Getpid()
+ n := 0
+ f.Fuzz(func(t *testing.T, _ []byte) {
+ name := fmt.Sprintf("count/%v.%d", pid, n)
+ if err := os.WriteFile(name, nil, 0666); err != nil {
+ t.Fatal(err)
+ }
+ n++
+ })
+}
+-- check_file_count.go --
+// +build ignore
+
+package main
+
+import (
+ "fmt"
+ "os"
+ "strconv"
+)
+
+func main() {
+ dir, err := os.ReadDir("count")
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ }
+ got := len(dir)
+ want, _ := strconv.Atoi(os.Args[1])
+ if got != want {
+ fmt.Fprintf(os.Stderr, "got %d files; want %d\n", got, want)
+ os.Exit(1)
+ }
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_io_error.txt b/src/cmd/go/testdata/script/test_fuzz_io_error.txt
new file mode 100644
index 0000000..4c7ab4c
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_io_error.txt
@@ -0,0 +1,101 @@
+# Test that when the coordinator experiences an I/O error communicating
+# with a worker, the coordinator stops the worker and reports the error.
+# The coordinator should not record a crasher.
+#
+# We simulate an I/O error in the test by writing garbage to fuzz_out.
+# This is unlikely, but possible. It's difficult to simulate interruptions
+# due to ^C and EOF errors which are more common. We don't report those.
+[short] skip
+[!darwin] [!linux] [!windows] skip
+
+# If the I/O error occurs before F.Fuzz is called, the coordinator should
+# stop the worker and say that.
+! go test -fuzz=FuzzClosePipeBefore -parallel=1
+stdout '\s*fuzzing process terminated without fuzzing:'
+! stdout 'communicating with fuzzing process'
+! exists testdata
+
+# If the I/O error occurs after F.Fuzz is called (unlikely), just exit.
+# It's hard to distinguish this case from the worker being interrupted by ^C
+# or exiting with status 0 (which it should do when interrupted by ^C).
+! go test -fuzz=FuzzClosePipeAfter -parallel=1
+stdout '^\s*communicating with fuzzing process: invalid character ''!'' looking for beginning of value$'
+! exists testdata
+
+-- go.mod --
+module test
+
+go 1.17
+-- io_error_test.go --
+package io_error
+
+import (
+ "flag"
+ "testing"
+ "time"
+)
+
+func isWorker() bool {
+ f := flag.Lookup("test.fuzzworker")
+ if f == nil {
+ return false
+ }
+ get, ok := f.Value.(flag.Getter)
+ if !ok {
+ return false
+ }
+ return get.Get() == interface{}(true)
+}
+
+func FuzzClosePipeBefore(f *testing.F) {
+ if isWorker() {
+ sendGarbageToCoordinator(f)
+ time.Sleep(3600 * time.Second) // pause until coordinator terminates the process
+ }
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+func FuzzClosePipeAfter(f *testing.F) {
+ f.Fuzz(func(t *testing.T, _ []byte) {
+ if isWorker() {
+ sendGarbageToCoordinator(t)
+ time.Sleep(3600 * time.Second) // pause until coordinator terminates the process
+ }
+ })
+}
+-- io_error_windows_test.go --
+package io_error
+
+import (
+ "fmt"
+ "os"
+ "testing"
+)
+
+func sendGarbageToCoordinator(tb testing.TB) {
+ v := os.Getenv("GO_TEST_FUZZ_WORKER_HANDLES")
+ var fuzzInFD, fuzzOutFD uintptr
+ if _, err := fmt.Sscanf(v, "%x,%x", &fuzzInFD, &fuzzOutFD); err != nil {
+ tb.Fatalf("parsing GO_TEST_FUZZ_WORKER_HANDLES: %v", err)
+ }
+ f := os.NewFile(fuzzOutFD, "fuzz_out")
+ if _, err := f.Write([]byte("!!")); err != nil {
+ tb.Fatalf("writing fuzz_out: %v", err)
+ }
+}
+-- io_error_notwindows_test.go --
+// +build !windows
+
+package io_error
+
+import (
+ "os"
+ "testing"
+)
+
+func sendGarbageToCoordinator(tb testing.TB) {
+ f := os.NewFile(4, "fuzz_out")
+ if _, err := f.Write([]byte("!!")); err != nil {
+ tb.Fatalf("writing fuzz_out: %v", err)
+ }
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_match.txt b/src/cmd/go/testdata/script/test_fuzz_match.txt
new file mode 100644
index 0000000..3a2ca63
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_match.txt
@@ -0,0 +1,39 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+# Matches only fuzz targets to test.
+go test standalone_fuzz_test.go
+! stdout '^ok.*\[no tests to run\]'
+stdout '^ok'
+
+# Matches only for fuzzing.
+go test -fuzz Fuzz -fuzztime 1x standalone_fuzz_test.go
+! stdout '^ok.*\[no tests to run\]'
+stdout '^ok'
+
+# Matches none for fuzzing but will run the fuzz target as a test.
+go test -fuzz ThisWillNotMatch -fuzztime 1x standalone_fuzz_test.go
+! stdout '^ok.*no tests to run'
+stdout '^ok'
+stdout 'no targets to fuzz'
+
+[short] stop
+
+# Matches only fuzz targets to test with -run.
+go test -run Fuzz standalone_fuzz_test.go
+! stdout '^ok.*\[no tests to run\]'
+stdout '^ok'
+
+# Matches no fuzz targets.
+go test -run ThisWillNotMatch standalone_fuzz_test.go
+stdout '^ok.*no tests to run'
+! stdout 'no targets to fuzz'
+
+-- standalone_fuzz_test.go --
+package standalone_fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Fuzz(func (*testing.T, []byte) {})
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_minimize.txt b/src/cmd/go/testdata/script/test_fuzz_minimize.txt
new file mode 100644
index 0000000..f0adb9e
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_minimize.txt
@@ -0,0 +1,200 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+[short] skip
+
+# We clean the fuzz cache during this test. Don't clean the user's cache.
+env GOCACHE=$WORK/gocache
+
+# Test that fuzzminimizetime cannot be negative seconds
+! go test -fuzz=FuzzMinimizerRecoverable -run=FuzzMinimizerRecoverable -fuzztime=10000x -fuzzminimizetime=-1ms minimizer_test.go
+! stdout '^ok'
+! stdout 'contains a non-zero byte'
+stdout 'invalid duration'
+stdout FAIL
+
+# Test that fuzzminimizetime cannot be negative times
+! go test -fuzz=FuzzMinimizerRecoverable -run=FuzzMinimizerRecoverable -fuzztime=10000x -fuzzminimizetime=-1x minimizer_test.go
+! stdout '^ok'
+! stdout 'contains a non-zero byte'
+stdout 'invalid count'
+stdout FAIL
+
+# Test that fuzzminimizetime can be zero seconds, and minimization is disabled
+! go test -fuzz=FuzzMinimizeZeroDurationSet -run=FuzzMinimizeZeroDurationSet -fuzztime=10000x -fuzzminimizetime=0s minimizer_test.go
+! stdout '^ok'
+! stdout 'minimizing'
+stdout 'there was an Error'
+stdout FAIL
+
+# Test that fuzzminimizetime can be zero times, and minimization is disabled
+! go test -fuzz=FuzzMinimizeZeroLimitSet -run=FuzzMinimizeZeroLimitSet -fuzztime=10000x -fuzzminimizetime=0x minimizer_test.go
+! stdout '^ok'
+! stdout 'minimizing'
+stdout 'there was an Error'
+stdout FAIL
+
+# Test that minimization is working for recoverable errors.
+! go test -fuzz=FuzzMinimizerRecoverable -run=FuzzMinimizerRecoverable -fuzztime=10000x minimizer_test.go
+! stdout '^ok'
+stdout 'got the minimum size!'
+stdout 'contains a non-zero byte'
+stdout FAIL
+
+# Check that the bytes written to testdata are of length 50 (the minimum size)
+go run check_testdata.go FuzzMinimizerRecoverable 50
+
+# Test that re-running the minimized value causes a crash.
+! go test -run=FuzzMinimizerRecoverable minimizer_test.go
+rm testdata
+
+# Test that minimization is working for non-recoverable errors.
+! go test -fuzz=FuzzMinimizerNonrecoverable -run=FuzzMinimizerNonrecoverable -fuzztime=10000x minimizer_test.go
+! stdout '^ok'
+stdout 'minimizing'
+stdout 'fuzzing process terminated unexpectedly: exit status 99'
+stdout FAIL
+
+# Check that re-running the value causes a crash.
+! go test -run=FuzzMinimizerNonrecoverable minimizer_test.go
+rm testdata
+
+# Clear the fuzzing cache. There may already be minimized inputs that would
+# interfere with the next stage of the test.
+go clean -fuzzcache
+
+# Test that minimization can be cancelled by fuzzminimizetime and the latest
+# crash will still be logged and written to testdata.
+! go test -fuzz=FuzzMinimizerRecoverable -run=FuzzMinimizerRecoverable -fuzztime=100x -fuzzminimizetime=1x minimizer_test.go
+! stdout '^ok'
+stdout 'testdata[/\\]fuzz[/\\]FuzzMinimizerRecoverable[/\\]'
+! stdout 'got the minimum size!' # it shouldn't have had enough time to minimize it
+stdout FAIL
+
+# Test that re-running the unminimized value causes a crash.
+! go test -run=FuzzMinimizerRecoverable minimizer_test.go
+
+# TODO(jayconrod,katiehockman): add a test which verifies that the right bytes
+# are written to testdata in the case of an interrupt during minimization.
+
+-- go.mod --
+module m
+
+go 1.16
+-- minimizer_test.go --
+package fuzz_test
+
+import (
+ "os"
+ "testing"
+)
+
+func FuzzMinimizeZeroDurationSet(f *testing.F) {
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if len(b) > 5 {
+ t.Errorf("there was an Error")
+ }
+ })
+}
+
+func FuzzMinimizeZeroLimitSet(f *testing.F) {
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if len(b) > 5 {
+ t.Errorf("there was an Error")
+ }
+ })
+}
+
+func FuzzMinimizerRecoverable(f *testing.F) {
+ f.Add(make([]byte, 100))
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if len(b) < 50 {
+ // Make sure that b is large enough that it can be minimized
+ return
+ }
+ // Given the randomness of the mutations, this should allow the
+ // minimizer to trim down the value a bit.
+ for _, n := range b {
+ if n != 0 {
+ if len(b) == 50 {
+ t.Log("got the minimum size!")
+ }
+ t.Fatal("contains a non-zero byte")
+ }
+ }
+ })
+}
+
+func FuzzMinimizerNonrecoverable(f *testing.F) {
+ f.Add(make([]byte, 100))
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if len(b) < 50 {
+ // Make sure that b is large enough that it can be minimized
+ return
+ }
+ // Given the randomness of the mutations, this should allow the
+ // minimizer to trim down the value a bit.
+ for _, n := range b {
+ if n != 0 {
+ t.Log("contains a non-zero byte")
+ os.Exit(99)
+ }
+ }
+ })
+}
+-- check_testdata.go --
+// +build ignore
+
+package main
+
+import (
+ "bytes"
+ "fmt"
+ "io/ioutil"
+ "os"
+ "path/filepath"
+ "strconv"
+)
+
+func main() {
+ target := os.Args[1]
+ numBytes, err := strconv.Atoi(os.Args[2])
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ }
+
+ // Open the file in testdata (there should only be one)
+ dir := fmt.Sprintf("testdata/fuzz/%s", target)
+ files, err := ioutil.ReadDir(dir)
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ }
+ if len(files) != 1 {
+ fmt.Fprintf(os.Stderr, "expected one file, got %d", len(files))
+ os.Exit(1)
+ }
+ got, err := ioutil.ReadFile(filepath.Join(dir, files[0].Name()))
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ }
+
+ // Trim the newline at the end of the file
+ got = bytes.TrimSpace(got)
+
+ // Make sure that there were exactly 100 bytes written to the corpus entry
+ prefix := []byte("[]byte(")
+ i := bytes.Index(got, prefix)
+ gotBytes := got[i+len(prefix) : len(got)-1]
+ s, err := strconv.Unquote(string(gotBytes))
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ }
+ if want, got := numBytes, len(s); want != got {
+ fmt.Fprintf(os.Stderr, "want %d bytes, got %d\n", want, got)
+ os.Exit(1)
+ }
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_minimize_interesting.txt b/src/cmd/go/testdata/script/test_fuzz_minimize_interesting.txt
new file mode 100644
index 0000000..5e1d90d
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_minimize_interesting.txt
@@ -0,0 +1,112 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+# Instrumentation only supported on 64-bit architectures.
+[!amd64] [!arm64] skip
+
+# Test that when an interesting value is discovered (one that expands coverage),
+# the fuzzing engine minimizes it before writing it to the cache.
+#
+# The program below starts with a seed value of length 100, but more coverage
+# will be found for any value other than the seed. We should end with a value
+# in the cache of length 1 (the minimizer currently does not produce empty
+# strings). check_cache.go confirms that.
+#
+# We would like to verify that ALL values in the cache were minimized to a
+# length of 1, but this isn't always possible when new coverage is found in
+# functions called by testing or internal/fuzz in the background.
+
+go test -c -fuzz=. # Build using shared build cache for speed.
+env GOCACHE=$WORK/gocache
+exec ./fuzz.test$GOEXE -test.fuzzcachedir=$GOCACHE/fuzz -test.fuzz=. -test.fuzztime=1000x
+go run check_cache.go $GOCACHE/fuzz/FuzzMin
+
+-- go.mod --
+module fuzz
+
+go 1.17
+-- fuzz_test.go --
+package fuzz
+
+import (
+ "bytes"
+ "testing"
+)
+
+func FuzzMin(f *testing.F) {
+ seed := bytes.Repeat([]byte("a"), 20)
+ f.Add(seed)
+ f.Fuzz(func(t *testing.T, buf []byte) {
+ if bytes.Equal(buf, seed) {
+ return
+ }
+ if n := sum(buf); n < 0 {
+ t.Error("sum cannot be negative")
+ }
+ })
+}
+
+func sum(buf []byte) int {
+ n := 0
+ for _, b := range buf {
+ n += int(b)
+ }
+ return n
+}
+-- check_cache.go --
+//go:build ignore
+// +build ignore
+
+// check_cache.go checks that each file in the cached corpus has a []byte
+// of length at most 1. This verifies that at least one cached input is minimized.
+package main
+
+import (
+ "bytes"
+ "fmt"
+ "os"
+ "path/filepath"
+ "regexp"
+ "strconv"
+)
+
+func main() {
+ dir := os.Args[1]
+ ents, err := os.ReadDir(dir)
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ }
+ for _, ent := range ents {
+ name := filepath.Join(dir, ent.Name())
+ if good, err := checkCacheFile(name); err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ } else if good {
+ os.Exit(0)
+ }
+ }
+ fmt.Fprintln(os.Stderr, "no cached inputs were minimized")
+ os.Exit(1)
+}
+
+func checkCacheFile(name string) (good bool, err error) {
+ data, err := os.ReadFile(name)
+ if err != nil {
+ return false, err
+ }
+ for _, line := range bytes.Split(data, []byte("\n")) {
+ m := valRe.FindSubmatch(line)
+ if m == nil {
+ continue
+ }
+ if s, err := strconv.Unquote(string(m[1])); err != nil {
+ return false, err
+ } else if len(s) <= 1 {
+ return true, nil
+ }
+ }
+ return false, nil
+}
+
+var valRe = regexp.MustCompile(`^\[\]byte\(([^)]+)\)$`)
diff --git a/src/cmd/go/testdata/script/test_fuzz_multiple.txt b/src/cmd/go/testdata/script/test_fuzz_multiple.txt
new file mode 100644
index 0000000..6a7732f
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_multiple.txt
@@ -0,0 +1,51 @@
+# This test checks that 'go test' prints a reasonable error when fuzzing is
+# enabled, and multiple package or multiple fuzz targets match.
+# TODO(#46312): support fuzzing multiple targets in multiple packages.
+
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+[short] skip
+
+# With fuzzing disabled, multiple targets can be tested.
+go test ./...
+
+# With fuzzing enabled, at most one package may be tested,
+# even if only one package contains fuzz targets.
+! go test -fuzz=. ./...
+stderr '^cannot use -fuzz flag with multiple packages$'
+! go test -fuzz=. ./zero ./one
+stderr '^cannot use -fuzz flag with multiple packages$'
+go test -fuzz=. -fuzztime=1x ./one
+
+# With fuzzing enabled, at most one target in the same package may match.
+! go test -fuzz=. ./two
+stdout '^testing: will not fuzz, -fuzz matches more than one target: \[FuzzOne FuzzTwo\]$'
+go test -fuzz=FuzzTwo -fuzztime=1x ./two
+
+-- go.mod --
+module fuzz
+
+go 1.18
+-- zero/zero.go --
+package zero
+-- one/one_test.go --
+package one
+
+import "testing"
+
+func FuzzOne(f *testing.F) {
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+-- two/two_test.go --
+package two
+
+import "testing"
+
+func FuzzOne(f *testing.F) {
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+func FuzzTwo(f *testing.F) {
+ f.Fuzz(func(*testing.T, []byte) {})
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_mutate_crash.txt b/src/cmd/go/testdata/script/test_fuzz_mutate_crash.txt
new file mode 100644
index 0000000..1b8b79b
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_mutate_crash.txt
@@ -0,0 +1,295 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+# Tests that a crash caused by a mutator-discovered input writes the bad input
+# to testdata, and fails+reports correctly. This tests the end-to-end behavior
+# of the mutator finding a crash while fuzzing, adding it as a regression test
+# to the seed corpus in testdata, and failing the next time the test is run.
+
+[short] skip
+
+# Running the seed corpus for all of the targets should pass the first
+# time, since nothing in the seed corpus will cause a crash.
+go test
+
+# Running the fuzzer should find a crashing input quickly.
+! go test -fuzz=FuzzWithBug -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzWithBug[/\\]'
+stdout 'this input caused a crash!'
+go run check_testdata.go FuzzWithBug
+
+# Now, the failing bytes should have been added to the seed corpus for
+# the target, and should fail when run without fuzzing.
+! go test
+stdout 'testdata[/\\]fuzz[/\\]FuzzWithBug[/\\][a-f0-9]{64}'
+stdout 'this input caused a crash!'
+
+! go test -run=FuzzWithNilPanic -fuzz=FuzzWithNilPanic -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzWithNilPanic[/\\]'
+stdout 'runtime.Goexit'
+go run check_testdata.go FuzzWithNilPanic
+
+! go test -run=FuzzWithFail -fuzz=FuzzWithFail -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzWithFail[/\\]'
+go run check_testdata.go FuzzWithFail
+
+! go test -run=FuzzWithLogFail -fuzz=FuzzWithLogFail -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzWithLogFail[/\\]'
+stdout 'logged something'
+go run check_testdata.go FuzzWithLogFail
+
+! go test -run=FuzzWithErrorf -fuzz=FuzzWithErrorf -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzWithErrorf[/\\]'
+stdout 'errorf was called here'
+go run check_testdata.go FuzzWithErrorf
+
+! go test -run=FuzzWithFatalf -fuzz=FuzzWithFatalf -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzWithFatalf[/\\]'
+stdout 'fatalf was called here'
+go run check_testdata.go FuzzWithFatalf
+
+! go test -run=FuzzWithBadExit -fuzz=FuzzWithBadExit -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzWithBadExit[/\\]'
+stdout 'unexpectedly'
+go run check_testdata.go FuzzWithBadExit
+
+# Running the fuzzer should find a crashing input quickly for fuzzing two types.
+! go test -run=FuzzWithTwoTypes -fuzz=FuzzWithTwoTypes -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzWithTwoTypes[/\\]'
+stdout 'these inputs caused a crash!'
+go run check_testdata.go FuzzWithTwoTypes
+
+# Running the fuzzer should find a crashing input quickly for an integer.
+! go test -run=FuzzInt -fuzz=FuzzInt -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzInt[/\\]'
+stdout 'this input caused a crash!'
+go run check_testdata.go FuzzInt
+
+! go test -run=FuzzUint -fuzz=FuzzUint -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzUint[/\\]'
+stdout 'this input caused a crash!'
+go run check_testdata.go FuzzUint
+
+# Running the fuzzer should find a crashing input quickly for a bool.
+! go test -run=FuzzBool -fuzz=FuzzBool -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzBool[/\\]'
+stdout 'this input caused a crash!'
+go run check_testdata.go FuzzBool
+
+# Running the fuzzer should find a crashing input quickly for a float.
+! go test -run=FuzzFloat -fuzz=FuzzFloat -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzFloat[/\\]'
+stdout 'this input caused a crash!'
+go run check_testdata.go FuzzFloat
+
+# Running the fuzzer should find a crashing input quickly for a byte.
+! go test -run=FuzzByte -fuzz=FuzzByte -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzByte[/\\]'
+stdout 'this input caused a crash!'
+go run check_testdata.go FuzzByte
+
+# Running the fuzzer should find a crashing input quickly for a rune.
+! go test -run=FuzzRune -fuzz=FuzzRune -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzRune[/\\]'
+stdout 'this input caused a crash!'
+go run check_testdata.go FuzzRune
+
+# Running the fuzzer should find a crashing input quickly for a string.
+! go test -run=FuzzString -fuzz=FuzzString -fuzztime=100x -fuzzminimizetime=1000x
+stdout 'testdata[/\\]fuzz[/\\]FuzzString[/\\]'
+stdout 'this input caused a crash!'
+go run check_testdata.go FuzzString
+
+-- go.mod --
+module m
+
+go 1.16
+-- fuzz_crash_test.go --
+package fuzz_crash
+
+import (
+ "os"
+ "testing"
+)
+
+func FuzzWithBug(f *testing.F) {
+ f.Add([]byte("aa"))
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if string(b) != "aa" {
+ panic("this input caused a crash!")
+ }
+ })
+}
+
+func FuzzWithNilPanic(f *testing.F) {
+ f.Add([]byte("aa"))
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if string(b) != "aa" {
+ panic(nil)
+ }
+ })
+}
+
+func FuzzWithFail(f *testing.F) {
+ f.Add([]byte("aa"))
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if string(b) != "aa" {
+ t.Fail()
+ }
+ })
+}
+
+func FuzzWithLogFail(f *testing.F) {
+ f.Add([]byte("aa"))
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if string(b) != "aa" {
+ t.Log("logged something")
+ t.Fail()
+ }
+ })
+}
+
+func FuzzWithErrorf(f *testing.F) {
+ f.Add([]byte("aa"))
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if string(b) != "aa" {
+ t.Errorf("errorf was called here")
+ }
+ })
+}
+
+func FuzzWithFatalf(f *testing.F) {
+ f.Add([]byte("aa"))
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if string(b) != "aa" {
+ t.Fatalf("fatalf was called here")
+ }
+ })
+}
+
+func FuzzWithBadExit(f *testing.F) {
+ f.Add([]byte("aa"))
+ f.Fuzz(func(t *testing.T, b []byte) {
+ if string(b) != "aa" {
+ os.Exit(1)
+ }
+ })
+}
+
+func FuzzWithTwoTypes(f *testing.F) {
+ f.Fuzz(func(t *testing.T, a, b []byte) {
+ if len(a) > 0 && len(b) > 0 {
+ panic("these inputs caused a crash!")
+ }
+ })
+}
+
+func FuzzInt(f *testing.F) {
+ f.Add(0)
+ f.Fuzz(func(t *testing.T, a int) {
+ if a != 0 {
+ panic("this input caused a crash!")
+ }
+ })
+}
+
+func FuzzUint(f *testing.F) {
+ f.Add(uint(0))
+ f.Fuzz(func(t *testing.T, a uint) {
+ if a != 0 {
+ panic("this input caused a crash!")
+ }
+ })
+}
+
+func FuzzBool(f *testing.F) {
+ f.Add(false)
+ f.Fuzz(func(t *testing.T, a bool) {
+ if a {
+ panic("this input caused a crash!")
+ }
+ })
+}
+
+func FuzzFloat(f *testing.F) {
+ f.Fuzz(func(t *testing.T, a float64) {
+ if a != float64(int64(a)) {
+ // It has a decimal, so it was mutated by division
+ panic("this input caused a crash!")
+ }
+ })
+}
+
+func FuzzByte(f *testing.F) {
+ f.Add(byte(0))
+ f.Fuzz(func(t *testing.T, a byte) {
+ if a != 0 {
+ panic("this input caused a crash!")
+ }
+ })
+}
+
+func FuzzRune(f *testing.F) {
+ f.Add(rune(0))
+ f.Fuzz(func(t *testing.T, a rune) {
+ if a != 0 {
+ panic("this input caused a crash!")
+ }
+ })
+}
+
+func FuzzString(f *testing.F) {
+ f.Add("")
+ f.Fuzz(func(t *testing.T, a string) {
+ if a != "" {
+ panic("this input caused a crash!")
+ }
+ })
+}
+
+-- check_testdata.go --
+// +build ignore
+
+package main
+
+import (
+ "bytes"
+ "crypto/sha256"
+ "fmt"
+ "io/ioutil"
+ "os"
+ "path/filepath"
+)
+
+func main() {
+ target := os.Args[1]
+ dir := filepath.Join("testdata/fuzz", target)
+
+ files, err := ioutil.ReadDir(dir)
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ }
+
+ if len(files) == 0 {
+ fmt.Fprintf(os.Stderr, "expect at least one new mutation to be written to testdata\n")
+ os.Exit(1)
+ }
+
+ fname := files[0].Name()
+ contents, err := ioutil.ReadFile(filepath.Join(dir, fname))
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ }
+ if bytes.Equal(contents, []byte("aa")) {
+ fmt.Fprintf(os.Stderr, "newly written testdata entry was not mutated\n")
+ os.Exit(1)
+ }
+ // The hash of the bytes in the file should match the filename.
+ h := []byte(fmt.Sprintf("%x", sha256.Sum256(contents)))
+ if !bytes.Equal([]byte(fname), h) {
+ fmt.Fprintf(os.Stderr, "hash of bytes %q does not match filename %q\n", h, fname)
+ os.Exit(1)
+ }
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_mutate_fail.txt b/src/cmd/go/testdata/script/test_fuzz_mutate_fail.txt
new file mode 100644
index 0000000..935c22a
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_mutate_fail.txt
@@ -0,0 +1,103 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+# Check that if a worker does not call F.Fuzz or calls F.Fail first,
+# 'go test' exits non-zero and no crasher is recorded.
+
+[short] skip
+
+! go test -fuzz=FuzzReturn
+! exists testdata
+
+! go test -fuzz=FuzzSkip
+! exists testdata
+
+! go test -fuzz=FuzzFail
+! exists testdata
+
+! go test -fuzz=FuzzPanic
+! exists testdata
+
+! go test -fuzz=FuzzNilPanic
+! exists testdata
+
+! go test -fuzz=FuzzGoexit
+! exists testdata
+
+! go test -fuzz=FuzzExit
+! exists testdata
+
+-- go.mod --
+module m
+
+go 1.17
+-- fuzz_fail_test.go --
+package fuzz_fail
+
+import (
+ "flag"
+ "os"
+ "runtime"
+ "testing"
+)
+
+func isWorker() bool {
+ f := flag.Lookup("test.fuzzworker")
+ if f == nil {
+ return false
+ }
+ get, ok := f.Value.(flag.Getter)
+ if !ok {
+ return false
+ }
+ return get.Get() == interface{}(true)
+}
+
+func FuzzReturn(f *testing.F) {
+ if isWorker() {
+ return
+ }
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+func FuzzSkip(f *testing.F) {
+ if isWorker() {
+ f.Skip()
+ }
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+func FuzzFail(f *testing.F) {
+ if isWorker() {
+ f.Fail()
+ }
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+func FuzzPanic(f *testing.F) {
+ if isWorker() {
+ panic("nope")
+ }
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+func FuzzNilPanic(f *testing.F) {
+ if isWorker() {
+ panic(nil)
+ }
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+func FuzzGoexit(f *testing.F) {
+ if isWorker() {
+ runtime.Goexit()
+ }
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+func FuzzExit(f *testing.F) {
+ if isWorker() {
+ os.Exit(99)
+ }
+ f.Fuzz(func(*testing.T, []byte) {})
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_mutator.txt b/src/cmd/go/testdata/script/test_fuzz_mutator.txt
new file mode 100644
index 0000000..9d0738e
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_mutator.txt
@@ -0,0 +1,166 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+# Test basic fuzzing mutator behavior.
+#
+# fuzz_test.go has two fuzz targets (FuzzA, FuzzB) which both add a seed value.
+# Each fuzz function writes the input to a log file. The coordinator and worker
+# use separate log files. check_logs.go verifies that the coordinator only
+# tests seed values and the worker tests mutated values on the fuzz target.
+
+[short] skip
+
+go test -fuzz=FuzzA -fuzztime=100x -parallel=1 -log=fuzz
+go run check_logs.go fuzz fuzz.worker
+
+# TODO(b/181800488): remove -parallel=1, here and below. For now, when a
+# crash is found, all workers keep running, wasting resources and reducing
+# the number of executions available to the minimizer, increasing flakiness.
+
+# Test that the mutator is good enough to find several unique mutations.
+! go test -fuzz=FuzzMutator -parallel=1 -fuzztime=100x mutator_test.go
+! stdout '^ok'
+stdout FAIL
+stdout 'mutator found enough unique mutations'
+
+-- go.mod --
+module m
+
+go 1.16
+-- fuzz_test.go --
+package fuzz_test
+
+import (
+ "flag"
+ "fmt"
+ "os"
+ "testing"
+)
+
+var (
+ logPath = flag.String("log", "", "path to log file")
+ logFile *os.File
+)
+
+func TestMain(m *testing.M) {
+ flag.Parse()
+ var err error
+ logFile, err = os.OpenFile(*logPath, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0666)
+ if os.IsExist(err) {
+ *logPath += ".worker"
+ logFile, err = os.OpenFile(*logPath, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0666)
+ }
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ }
+ os.Exit(m.Run())
+}
+
+func FuzzA(f *testing.F) {
+ f.Add([]byte("seed"))
+ f.Fuzz(func(t *testing.T, b []byte) {
+ fmt.Fprintf(logFile, "FuzzA %q\n", b)
+ })
+}
+
+func FuzzB(f *testing.F) {
+ f.Add([]byte("seed"))
+ f.Fuzz(func(t *testing.T, b []byte) {
+ fmt.Fprintf(logFile, "FuzzB %q\n", b)
+ })
+}
+
+-- check_logs.go --
+// +build ignore
+
+package main
+
+import (
+ "bufio"
+ "bytes"
+ "fmt"
+ "io"
+ "os"
+ "strings"
+)
+
+func main() {
+ coordPath, workerPath := os.Args[1], os.Args[2]
+
+ coordLog, err := os.Open(coordPath)
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ }
+ defer coordLog.Close()
+ if err := checkCoordLog(coordLog); err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ }
+
+ workerLog, err := os.Open(workerPath)
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ }
+ defer workerLog.Close()
+ if err := checkWorkerLog(workerLog); err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ os.Exit(1)
+ }
+}
+
+func checkCoordLog(r io.Reader) error {
+ b, err := io.ReadAll(r)
+ if err != nil {
+ return err
+ }
+ if string(bytes.TrimSpace(b)) != `FuzzB "seed"` {
+ return fmt.Errorf("coordinator: did not test FuzzB seed")
+ }
+ return nil
+}
+
+func checkWorkerLog(r io.Reader) error {
+ scan := bufio.NewScanner(r)
+ var sawAMutant bool
+ for scan.Scan() {
+ line := scan.Text()
+ if !strings.HasPrefix(line, "FuzzA ") {
+ return fmt.Errorf("worker: tested something other than target: %s", line)
+ }
+ if strings.TrimPrefix(line, "FuzzA ") != `"seed"` {
+ sawAMutant = true
+ }
+ }
+ if err := scan.Err(); err != nil && err != bufio.ErrTooLong {
+ return err
+ }
+ if !sawAMutant {
+ return fmt.Errorf("worker: did not test any mutants")
+ }
+ return nil
+}
+-- mutator_test.go --
+package fuzz_test
+
+import (
+ "testing"
+)
+
+// TODO(katiehockman): re-work this test once we have a better fuzzing engine
+// (ie. more mutations, and compiler instrumentation)
+func FuzzMutator(f *testing.F) {
+ // TODO(katiehockman): simplify this once we can dedupe crashes (e.g.
+ // replace map with calls to panic, and simply count the number of crashes
+ // that were added to testdata)
+ crashes := make(map[string]bool)
+ // No seed corpus initiated
+ f.Fuzz(func(t *testing.T, b []byte) {
+ crashes[string(b)] = true
+ if len(crashes) >= 10 {
+ panic("mutator found enough unique mutations")
+ }
+ })
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_mutator_repeat.txt b/src/cmd/go/testdata/script/test_fuzz_mutator_repeat.txt
new file mode 100644
index 0000000..0924ed3
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_mutator_repeat.txt
@@ -0,0 +1,66 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+# Verify that the fuzzing engine records the actual crashing input, even when
+# a worker process terminates without communicating the crashing input back
+# to the coordinator.
+
+[short] skip
+
+# Start fuzzing. The worker crashes after ~100 iterations.
+# The fuzz function writes the crashing input to "want" before exiting.
+# The fuzzing engine reconstructs the crashing input and saves it to testdata.
+! exists want
+! go test -fuzz=. -parallel=1
+stdout 'fuzzing process terminated unexpectedly'
+stdout 'Crash written to testdata'
+
+# Run the fuzz target without fuzzing. The fuzz function is called with the
+# crashing input in testdata. The test passes if that input is identical to
+# the one saved in "want".
+exists want
+go test -want=want
+
+-- go.mod --
+module fuzz
+
+go 1.17
+-- fuzz_test.go --
+package fuzz
+
+import (
+ "bytes"
+ "flag"
+ "os"
+ "testing"
+)
+
+var wantFlag = flag.String("want", "", "file containing previous crashing input")
+
+func FuzzRepeat(f *testing.F) {
+ i := 0
+ f.Fuzz(func(t *testing.T, b []byte) {
+ i++
+ if i == 100 {
+ f, err := os.OpenFile("want", os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0666)
+ if err != nil {
+ // Couldn't create the file, probably because it already exists,
+ // and we're minimizing now. Return without crashing.
+ return
+ }
+ f.Write(b)
+ f.Close()
+ os.Exit(1) // crash without communicating
+ }
+
+ if *wantFlag != "" {
+ want, err := os.ReadFile(*wantFlag)
+ if err != nil {
+ t.Fatal(err)
+ }
+ if !bytes.Equal(want, b) {
+ t.Fatalf("inputs are not equal!\n got: %q\nwant:%q", b, want)
+ }
+ }
+ })
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_non_crash_signal.txt b/src/cmd/go/testdata/script/test_fuzz_non_crash_signal.txt
new file mode 100644
index 0000000..1568757
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_non_crash_signal.txt
@@ -0,0 +1,55 @@
+# NOTE: this test is skipped on Windows, since there's no concept of signals.
+# When a process terminates another process, it provides an exit code.
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!freebsd] [!linux] skip
+[short] skip
+
+# FuzzNonCrash sends itself a signal that does not appear to be a crash.
+# We should not save a crasher.
+! go test -fuzz=FuzzNonCrash
+! exists testdata
+! stdout unreachable
+! stderr unreachable
+stdout 'fuzzing process terminated by unexpected signal; no crash will be recorded: signal: killed'
+
+# FuzzCrash sends itself a signal that looks like a crash.
+# We should save a crasher.
+! go test -fuzz=FuzzCrash
+exists testdata/fuzz/FuzzCrash
+stdout 'fuzzing process terminated unexpectedly'
+
+-- go.mod --
+module test
+
+go 1.17
+-- fuzz_posix_test.go --
+// +build darwin freebsd linux
+
+package fuzz
+
+import (
+ "syscall"
+ "testing"
+)
+
+func FuzzNonCrash(f *testing.F) {
+ f.Fuzz(func(*testing.T, bool) {
+ pid := syscall.Getpid()
+ if err := syscall.Kill(pid, syscall.SIGKILL); err != nil {
+ panic(err)
+ }
+ // signal may not be received immediately. Wait for it.
+ select{}
+ })
+}
+
+func FuzzCrash(f *testing.F) {
+ f.Fuzz(func(*testing.T, bool) {
+ pid := syscall.Getpid()
+ if err := syscall.Kill(pid, syscall.SIGILL); err != nil {
+ panic(err)
+ }
+ // signal may not be received immediately. Wait for it.
+ select{}
+ })
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_parallel.txt b/src/cmd/go/testdata/script/test_fuzz_parallel.txt
new file mode 100644
index 0000000..a49f30a
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_parallel.txt
@@ -0,0 +1,61 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+[short] skip
+
+# When running seed inputs, T.Parallel should let multiple inputs run in
+# parallel.
+go test -run=FuzzSeed
+
+# When fuzzing, T.Parallel should be safe to call, but it should have no effect.
+# We just check that it doesn't hang, which would be the most obvious
+# failure mode.
+# TODO(jayconrod): check for the string "after T.Parallel". It's not printed
+# by 'go test', so we can't distinguish that crasher from some other panic.
+! go test -run=FuzzMutate -fuzz=FuzzMutate
+exists testdata/fuzz/FuzzMutate
+
+-- go.mod --
+module fuzz_parallel
+
+go 1.17
+-- fuzz_parallel_test.go --
+package fuzz_parallel
+
+import (
+ "sort"
+ "sync"
+ "testing"
+)
+
+func FuzzSeed(f *testing.F) {
+ for _, v := range [][]byte{{'a'}, {'b'}, {'c'}} {
+ f.Add(v)
+ }
+
+ var mu sync.Mutex
+ var before, after []byte
+ f.Cleanup(func() {
+ sort.Slice(after, func(i, j int) bool { return after[i] < after[j] })
+ got := string(before) + string(after)
+ want := "abcabc"
+ if got != want {
+ f.Fatalf("got %q; want %q", got, want)
+ }
+ })
+
+ f.Fuzz(func(t *testing.T, b []byte) {
+ before = append(before, b...)
+ t.Parallel()
+ mu.Lock()
+ after = append(after, b...)
+ mu.Unlock()
+ })
+}
+
+func FuzzMutate(f *testing.F) {
+ f.Fuzz(func(t *testing.T, _ []byte) {
+ t.Parallel()
+ t.Error("after T.Parallel")
+ })
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_seed_corpus.txt b/src/cmd/go/testdata/script/test_fuzz_seed_corpus.txt
new file mode 100644
index 0000000..016b101
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_seed_corpus.txt
@@ -0,0 +1,168 @@
+# TODO(jayconrod): support shared memory on more platforms.
+[!darwin] [!linux] [!windows] skip
+
+[short] skip
+env GOCACHE=$WORK/cache
+
+# Test that fuzzing a target with a failure in f.Add prints the crash
+# and doesn't write anything to testdata/fuzz
+! go test -fuzz=FuzzWithAdd -run=FuzzWithAdd -fuzztime=1x
+! stdout ^ok
+! stdout 'Crash written to testdata[/\\]fuzz[/\\]FuzzWithAdd[/\\]'
+stdout FAIL
+
+# Test that fuzzing a target with a sucess in f.Add and a fuzztime of only
+# 1 does not produce a crash.
+go test -fuzz=FuzzWithGoodAdd -run=FuzzWithGoodAdd -fuzztime=1x
+stdout ok
+! stdout FAIL
+
+# Test that fuzzing a target with a failure in testdata/fuzz prints the crash
+# and doesn't write anything to testdata/fuzz
+! go test -fuzz=FuzzWithTestdata -run=FuzzWithTestdata -fuzztime=1x
+! stdout ^ok
+! stdout 'Crash written to testdata[/\\]fuzz[/\\]FuzzWithTestdata[/\\]'
+stdout FAIL
+
+# Test that fuzzing a target with no seed corpus or cache finds a crash, prints
+# it, and write it to testdata
+! go test -fuzz=FuzzWithNoCache -run=FuzzWithNoCache -fuzztime=1x
+! stdout ^ok
+stdout 'Crash written to testdata[/\\]fuzz[/\\]FuzzWithNoCache[/\\]'
+stdout FAIL
+
+# Write a crashing input to the cache
+mkdir $GOCACHE/fuzz/example.com/x/FuzzWithCache
+cp cache-file $GOCACHE/fuzz/example.com/x/FuzzWithCache/1
+
+# Test that fuzzing a target with a failure in the cache prints the crash
+# and writes this as a "new" crash to testdata/fuzz
+! go test -fuzz=FuzzWithCache -run=FuzzWithCache -fuzztime=1x
+! stdout ^ok
+stdout 'Crash written to testdata[/\\]fuzz[/\\]FuzzWithCache[/\\]'
+stdout FAIL
+
+# Clear the fuzz cache and make sure it's gone
+go clean -fuzzcache
+! exists $GOCACHE/fuzz
+
+# The tests below should operate the exact same as the previous tests. If -fuzz
+# is enabled, then whatever target is going to be fuzzed shouldn't be run by
+# anything other than the workers.
+
+# Test that fuzzing a target (with -run=None set) with a failure in f.Add prints
+# the crash and doesn't write anything to testdata/fuzz -fuzztime=1x
+! go test -fuzz=FuzzWithAdd -run=None
+! stdout ^ok
+! stdout 'Crash written to testdata[/\\]fuzz[/\\]FuzzWithAdd[/\\]'
+stdout FAIL
+
+# Test that fuzzing a target (with -run=None set) with a sucess in f.Add and a
+# fuzztime of only 1 does not produce a crash.
+go test -fuzz=FuzzWithGoodAdd -run=None -fuzztime=1x
+stdout ok
+! stdout FAIL
+
+# Test that fuzzing a target (with -run=None set) with a failure in
+# testdata/fuzz prints the crash and doesn't write anything to testdata/fuzz
+! go test -fuzz=FuzzWithTestdata -run=None -fuzztime=1x
+! stdout ^ok
+! stdout 'Crash written to testdata[/\\]fuzz[/\\]FuzzWithTestdata[/\\]'
+stdout FAIL
+
+# Write a crashing input to the cache
+mkdir $GOCACHE/fuzz/example.com/x/FuzzRunNoneWithCache
+cp cache-file $GOCACHE/fuzz/example.com/x/FuzzRunNoneWithCache/1
+
+# Test that fuzzing a target (with -run=None set) with a failure in the cache
+# prints the crash and writes this as a "new" crash to testdata/fuzz
+! go test -fuzz=FuzzRunNoneWithCache -run=None -fuzztime=1x
+! stdout ^ok
+stdout 'Crash written to testdata[/\\]fuzz[/\\]FuzzRunNoneWithCache[/\\]'
+stdout FAIL
+
+# Clear the fuzz cache and make sure it's gone
+go clean -fuzzcache
+! exists $GOCACHE/fuzz
+
+# The tests below should operate the exact same way for the previous tests with
+# a seed corpus (namely, they should still fail). However, the binary is built
+# without instrumentation, so this should be a "testing only" run which executes
+# the seed corpus before attempting to fuzz.
+
+go test -c
+! exec ./x.test$GOEXE -test.fuzz=FuzzWithAdd -test.run=FuzzWithAdd -test.fuzztime=1x -test.fuzzcachedir=$WORK/cache
+! stdout ^ok
+! stdout 'Crash written to testdata[/\\]fuzz[/\\]FuzzWithAdd[/\\]'
+stdout FAIL
+stderr warning
+
+go test -c
+! exec ./x.test$GOEXE -test.fuzz=FuzzWithTestdata -test.run=FuzzWithTestdata -test.fuzztime=1x -test.fuzzcachedir=$WORK/cache
+! stdout ^ok
+! stdout 'Crash written to testdata[/\\]fuzz[/\\]FuzzWithTestdata[/\\]'
+stdout FAIL
+stderr warning
+
+-- go.mod --
+module example.com/x
+
+go 1.16
+-- x_test.go --
+package x
+
+import "testing"
+
+func FuzzWithAdd(f *testing.F) {
+ f.Add(10)
+ f.Fuzz(func(t *testing.T, i int) {
+ if i == 10 {
+ t.Error("bad thing here")
+ }
+ })
+}
+
+func FuzzWithGoodAdd(f *testing.F) {
+ f.Add(10)
+ f.Fuzz(func(t *testing.T, i int) {
+ if i != 10 {
+ t.Error("bad thing here")
+ }
+ })
+}
+
+func FuzzWithTestdata(f *testing.F) {
+ f.Fuzz(func(t *testing.T, i int) {
+ if i == 10 {
+ t.Error("bad thing here")
+ }
+ })
+}
+
+func FuzzWithNoCache(f *testing.F) {
+ f.Fuzz(func(t *testing.T, i int) {
+ t.Error("bad thing here")
+ })
+}
+
+func FuzzWithCache(f *testing.F) {
+ f.Fuzz(func(t *testing.T, i int) {
+ if i == 10 {
+ t.Error("bad thing here")
+ }
+ })
+}
+
+func FuzzRunNoneWithCache(f *testing.F) {
+ f.Fuzz(func(t *testing.T, i int) {
+ if i == 10 {
+ t.Error("bad thing here")
+ }
+ })
+}
+-- testdata/fuzz/FuzzWithTestdata/1 --
+go test fuzz v1
+int(10)
+-- cache-file --
+go test fuzz v1
+int(10)
\ No newline at end of file
diff --git a/src/cmd/go/testdata/script/test_fuzz_setenv.txt b/src/cmd/go/testdata/script/test_fuzz_setenv.txt
new file mode 100644
index 0000000..9738697
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_setenv.txt
@@ -0,0 +1,45 @@
+[short] skip
+[!darwin] [!linux] [!windows] skip
+
+go test -fuzz=FuzzA -fuzztime=100x fuzz_setenv_test.go
+
+-- fuzz_setenv_test.go --
+package fuzz
+
+import (
+ "flag"
+ "os"
+ "testing"
+)
+
+func FuzzA(f *testing.F) {
+ if s := os.Getenv("TEST_FUZZ_SETENV_A"); isWorker() && s == "" {
+ f.Fatal("environment variable not set")
+ } else if !isWorker() && s != "" {
+ f.Fatal("environment variable already set")
+ }
+ f.Setenv("TEST_FUZZ_SETENV_A", "A")
+ if os.Getenv("TEST_FUZZ_SETENV_A") == "" {
+ f.Fatal("Setenv did not set environment variable")
+ }
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+func FuzzB(f *testing.F) {
+ if os.Getenv("TEST_FUZZ_SETENV_A") != "" {
+ f.Fatal("environment variable not cleared after FuzzA")
+ }
+ f.Skip()
+}
+
+func isWorker() bool {
+ f := flag.Lookup("test.fuzzworker")
+ if f == nil {
+ return false
+ }
+ get, ok := f.Value.(flag.Getter)
+ if !ok {
+ return false
+ }
+ return get.Get() == interface{}(true)
+}
diff --git a/src/cmd/go/testdata/script/test_fuzz_tag.txt b/src/cmd/go/testdata/script/test_fuzz_tag.txt
new file mode 100644
index 0000000..07ed5d6
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_tag.txt
@@ -0,0 +1,31 @@
+# Check that the gofuzzbeta tag is enabled by default and can be disabled.
+# TODO(jayconrod,katiehockman): before merging to master, restore the old
+# default and delete this test.
+
+[short] skip
+
+go test -list=.
+stdout Test
+stdout Fuzz
+
+go test -tags=
+
+-- go.mod --
+module fuzz
+
+go 1.17
+-- fuzz_test.go --
+// +build gofuzzbeta
+
+package fuzz
+
+import "testing"
+
+func Fuzz(f *testing.F) {
+ f.Add([]byte(nil))
+ f.Fuzz(func(*testing.T, []byte) {})
+}
+
+func Test(*testing.T) {}
+-- empty_test.go --
+package fuzz
diff --git a/src/cmd/link/internal/ld/data.go b/src/cmd/link/internal/ld/data.go
index 43a0e06..1898ee0 100644
--- a/src/cmd/link/internal/ld/data.go
+++ b/src/cmd/link/internal/ld/data.go
@@ -1782,7 +1782,9 @@
// Coverage instrumentation counters for libfuzzer.
if len(state.data[sym.SLIBFUZZER_EXTRA_COUNTER]) > 0 {
- state.allocateNamedSectionAndAssignSyms(&Segdata, "__libfuzzer_extra_counters", sym.SLIBFUZZER_EXTRA_COUNTER, sym.Sxxx, 06)
+ sect := state.allocateNamedSectionAndAssignSyms(&Segdata, "__libfuzzer_extra_counters", sym.SLIBFUZZER_EXTRA_COUNTER, sym.Sxxx, 06)
+ ldr.SetSymSect(ldr.LookupOrCreateSym("internal/fuzz._counters", 0), sect)
+ ldr.SetSymSect(ldr.LookupOrCreateSym("internal/fuzz._ecounters", 0), sect)
}
if len(state.data[sym.STLSBSS]) > 0 {
@@ -2522,6 +2524,7 @@
var noptr *sym.Section
var bss *sym.Section
var noptrbss *sym.Section
+ var fuzzCounters *sym.Section
for i, s := range Segdata.Sections {
if (ctxt.IsELF || ctxt.HeadType == objabi.Haix) && s.Name == ".tbss" {
continue
@@ -2533,17 +2536,17 @@
s.Vaddr = va
va += uint64(vlen)
Segdata.Length = va - Segdata.Vaddr
- if s.Name == ".data" {
+ switch s.Name {
+ case ".data":
data = s
- }
- if s.Name == ".noptrdata" {
+ case ".noptrdata":
noptr = s
- }
- if s.Name == ".bss" {
+ case ".bss":
bss = s
- }
- if s.Name == ".noptrbss" {
+ case ".noptrbss":
noptrbss = s
+ case "__libfuzzer_extra_counters":
+ fuzzCounters = s
}
}
@@ -2660,6 +2663,11 @@
ctxt.xdefine("runtime.enoptrbss", sym.SNOPTRBSS, int64(noptrbss.Vaddr+noptrbss.Length))
ctxt.xdefine("runtime.end", sym.SBSS, int64(Segdata.Vaddr+Segdata.Length))
+ if fuzzCounters != nil {
+ ctxt.xdefine("internal/fuzz._counters", sym.SLIBFUZZER_EXTRA_COUNTER, int64(fuzzCounters.Vaddr))
+ ctxt.xdefine("internal/fuzz._ecounters", sym.SLIBFUZZER_EXTRA_COUNTER, int64(fuzzCounters.Vaddr+fuzzCounters.Length))
+ }
+
if ctxt.IsSolaris() {
// On Solaris, in the runtime it sets the external names of the
// end symbols. Unset them and define separate symbols, so we
diff --git a/src/go/build/deps_test.go b/src/go/build/deps_test.go
index cbc77cf..a9939df 100644
--- a/src/go/build/deps_test.go
+++ b/src/go/build/deps_test.go
@@ -513,7 +513,10 @@
FMT, flag, runtime/debug, runtime/trace, internal/sysinfo, math/rand
< testing;
- internal/testlog, runtime/pprof, regexp
+ FMT, crypto/sha256, encoding/json, go/ast, go/parser, go/token, math/rand, encoding/hex, crypto/sha256
+ < internal/fuzz;
+
+ internal/fuzz, internal/testlog, runtime/pprof, regexp
< testing/internal/testdeps;
OS, flag, testing, internal/cfg
diff --git a/src/go/doc/example.go b/src/go/doc/example.go
index 274000c..fbbd846 100644
--- a/src/go/doc/example.go
+++ b/src/go/doc/example.go
@@ -44,13 +44,13 @@
// identifiers from other packages (or predeclared identifiers, such as
// "int") and the test file does not include a dot import.
// - The entire test file is the example: the file contains exactly one
-// example function, zero test or benchmark functions, and at least one
-// top-level function, type, variable, or constant declaration other
-// than the example function.
+// example function, zero test, fuzz target, or benchmark function, and at
+// least one top-level function, type, variable, or constant declaration
+// other than the example function.
func Examples(testFiles ...*ast.File) []*Example {
var list []*Example
for _, file := range testFiles {
- hasTests := false // file contains tests or benchmarks
+ hasTests := false // file contains tests, fuzz targets, or benchmarks
numDecl := 0 // number of non-import declarations in the file
var flist []*Example
for _, decl := range file.Decls {
@@ -64,7 +64,7 @@
}
numDecl++
name := f.Name.Name
- if isTest(name, "Test") || isTest(name, "Benchmark") {
+ if isTest(name, "Test") || isTest(name, "Benchmark") || isTest(name, "Fuzz") {
hasTests = true
continue
}
@@ -133,9 +133,9 @@
return "", false, false // no suitable comment found
}
-// isTest tells whether name looks like a test, example, or benchmark.
-// It is a Test (say) if there is a character after Test that is not a
-// lower-case letter. (We don't want Testiness.)
+// isTest tells whether name looks like a test, example, fuzz target, or
+// benchmark. It is a Test (say) if there is a character after Test that is not
+// a lower-case letter. (We don't want Testiness.)
func isTest(name, prefix string) bool {
if !strings.HasPrefix(name, prefix) {
return false
diff --git a/src/go/doc/example_test.go b/src/go/doc/example_test.go
index cf1b702..21b7129 100644
--- a/src/go/doc/example_test.go
+++ b/src/go/doc/example_test.go
@@ -307,6 +307,9 @@
func (X) BenchmarkFoo() {
}
+func (X) FuzzFoo() {
+}
+
func Example() {
fmt.Println("Hello, world!")
// Output: Hello, world!
@@ -326,6 +329,9 @@
func (X) BenchmarkFoo() {
}
+func (X) FuzzFoo() {
+}
+
func main() {
fmt.Println("Hello, world!")
}
diff --git a/src/internal/fuzz/coverage.go b/src/internal/fuzz/coverage.go
new file mode 100644
index 0000000..71d0132
--- /dev/null
+++ b/src/internal/fuzz/coverage.go
@@ -0,0 +1,115 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+import (
+ "fmt"
+ "internal/unsafeheader"
+ "math/bits"
+ "unsafe"
+)
+
+// coverage returns a []byte containing unique 8-bit counters for each edge of
+// the instrumented source code. This coverage data will only be generated if
+// `-d=libfuzzer` is set at build time. This can be used to understand the code
+// coverage of a test execution.
+func coverage() []byte {
+ addr := unsafe.Pointer(&_counters)
+ size := uintptr(unsafe.Pointer(&_ecounters)) - uintptr(addr)
+
+ var res []byte
+ *(*unsafeheader.Slice)(unsafe.Pointer(&res)) = unsafeheader.Slice{
+ Data: addr,
+ Len: int(size),
+ Cap: int(size),
+ }
+ return res
+}
+
+// ResetCovereage sets all of the counters for each edge of the instrumented
+// source code to 0.
+func ResetCoverage() {
+ cov := coverage()
+ for i := range cov {
+ cov[i] = 0
+ }
+}
+
+// SnapshotCoverage copies the current counter values into coverageSnapshot,
+// preserving them for later inspection. SnapshotCoverage also rounds each
+// counter down to the nearest power of two. This lets the coordinator store
+// multiple values for each counter by OR'ing them together.
+func SnapshotCoverage() {
+ cov := coverage()
+ for i, b := range cov {
+ b |= b >> 1
+ b |= b >> 2
+ b |= b >> 4
+ b -= b >> 1
+ coverageSnapshot[i] = b
+ }
+}
+
+// diffCoverage returns a set of bits set in snapshot but not in base.
+// If there are no new bits set, diffCoverage returns nil.
+func diffCoverage(base, snapshot []byte) []byte {
+ if len(base) != len(snapshot) {
+ panic(fmt.Sprintf("the number of coverage bits changed: before=%d, after=%d", len(base), len(snapshot)))
+ }
+ found := false
+ for i := range snapshot {
+ if snapshot[i]&^base[i] != 0 {
+ found = true
+ break
+ }
+ }
+ if !found {
+ return nil
+ }
+ diff := make([]byte, len(snapshot))
+ for i := range diff {
+ diff[i] = snapshot[i] &^ base[i]
+ }
+ return diff
+}
+
+// countNewCoverageBits returns the number of bits set in snapshot that are not
+// set in base.
+func countNewCoverageBits(base, snapshot []byte) int {
+ n := 0
+ for i := range snapshot {
+ n += bits.OnesCount8(snapshot[i] &^ base[i])
+ }
+ return n
+}
+
+// hasCoverageBit returns true if snapshot has at least one bit set that is
+// also set in base.
+func hasCoverageBit(base, snapshot []byte) bool {
+ for i := range snapshot {
+ if snapshot[i]&base[i] != 0 {
+ return true
+ }
+ }
+ return false
+}
+
+func countBits(cov []byte) int {
+ n := 0
+ for _, c := range cov {
+ n += bits.OnesCount8(c)
+ }
+ return n
+}
+
+var (
+ coverageEnabled = len(coverage()) > 0
+ coverageSnapshot = make([]byte, len(coverage()))
+
+ // _counters and _ecounters mark the start and end, respectively, of where
+ // the 8-bit coverage counters reside in memory. They're known to cmd/link,
+ // which specially assigns their addresses for this purpose.
+ _counters, _ecounters [0]byte
+)
diff --git a/src/internal/fuzz/encoding.go b/src/internal/fuzz/encoding.go
new file mode 100644
index 0000000..d3f24c3
--- /dev/null
+++ b/src/internal/fuzz/encoding.go
@@ -0,0 +1,240 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+import (
+ "bytes"
+ "fmt"
+ "go/ast"
+ "go/parser"
+ "go/token"
+ "strconv"
+)
+
+// encVersion1 will be the first line of a file with version 1 encoding.
+var encVersion1 = "go test fuzz v1"
+
+// marshalCorpusFile encodes an arbitrary number of arguments into the file format for the
+// corpus.
+func marshalCorpusFile(vals ...interface{}) []byte {
+ if len(vals) == 0 {
+ panic("must have at least one value to marshal")
+ }
+ b := bytes.NewBuffer([]byte(encVersion1 + "\n"))
+ // TODO(katiehockman): keep uint8 and int32 encoding where applicable,
+ // instead of changing to byte and rune respectively.
+ for _, val := range vals {
+ switch t := val.(type) {
+ case int, int8, int16, int64, uint, uint16, uint32, uint64, float32, float64, bool:
+ fmt.Fprintf(b, "%T(%v)\n", t, t)
+ case string:
+ fmt.Fprintf(b, "string(%q)\n", t)
+ case rune: // int32
+ fmt.Fprintf(b, "rune(%q)\n", t)
+ case byte: // uint8
+ fmt.Fprintf(b, "byte(%q)\n", t)
+ case []byte: // []uint8
+ fmt.Fprintf(b, "[]byte(%q)\n", t)
+ default:
+ panic(fmt.Sprintf("unsupported type: %T", t))
+ }
+ }
+ return b.Bytes()
+}
+
+// unmarshalCorpusFile decodes corpus bytes into their respective values.
+func unmarshalCorpusFile(b []byte) ([]interface{}, error) {
+ if len(b) == 0 {
+ return nil, fmt.Errorf("cannot unmarshal empty string")
+ }
+ lines := bytes.Split(b, []byte("\n"))
+ if len(lines) < 2 {
+ return nil, fmt.Errorf("must include version and at least one value")
+ }
+ if string(lines[0]) != encVersion1 {
+ return nil, fmt.Errorf("unknown encoding version: %s", lines[0])
+ }
+ var vals []interface{}
+ for _, line := range lines[1:] {
+ line = bytes.TrimSpace(line)
+ if len(line) == 0 {
+ continue
+ }
+ v, err := parseCorpusValue(line)
+ if err != nil {
+ return nil, fmt.Errorf("malformed line %q: %v", line, err)
+ }
+ vals = append(vals, v)
+ }
+ return vals, nil
+}
+
+func parseCorpusValue(line []byte) (interface{}, error) {
+ fs := token.NewFileSet()
+ expr, err := parser.ParseExprFrom(fs, "(test)", line, 0)
+ if err != nil {
+ return nil, err
+ }
+ call, ok := expr.(*ast.CallExpr)
+ if !ok {
+ return nil, fmt.Errorf("expected call expression")
+ }
+ if len(call.Args) != 1 {
+ return nil, fmt.Errorf("expected call expression with 1 argument; got %d", len(call.Args))
+ }
+ arg := call.Args[0]
+
+ if arrayType, ok := call.Fun.(*ast.ArrayType); ok {
+ if arrayType.Len != nil {
+ return nil, fmt.Errorf("expected []byte or primitive type")
+ }
+ elt, ok := arrayType.Elt.(*ast.Ident)
+ if !ok || elt.Name != "byte" {
+ return nil, fmt.Errorf("expected []byte")
+ }
+ lit, ok := arg.(*ast.BasicLit)
+ if !ok || lit.Kind != token.STRING {
+ return nil, fmt.Errorf("string literal required for type []byte")
+ }
+ s, err := strconv.Unquote(lit.Value)
+ if err != nil {
+ return nil, err
+ }
+ return []byte(s), nil
+ }
+
+ idType, ok := call.Fun.(*ast.Ident)
+ if !ok {
+ return nil, fmt.Errorf("expected []byte or primitive type")
+ }
+ if idType.Name == "bool" {
+ id, ok := arg.(*ast.Ident)
+ if !ok {
+ return nil, fmt.Errorf("malformed bool")
+ }
+ if id.Name == "true" {
+ return true, nil
+ } else if id.Name == "false" {
+ return false, nil
+ } else {
+ return nil, fmt.Errorf("true or false required for type bool")
+ }
+ }
+ var (
+ val string
+ kind token.Token
+ )
+ if op, ok := arg.(*ast.UnaryExpr); ok {
+ // Special case for negative numbers.
+ lit, ok := op.X.(*ast.BasicLit)
+ if !ok || (lit.Kind != token.INT && lit.Kind != token.FLOAT) {
+ return nil, fmt.Errorf("expected operation on int or float type")
+ }
+ if op.Op != token.SUB {
+ return nil, fmt.Errorf("unsupported operation on int: %v", op.Op)
+ }
+ val = op.Op.String() + lit.Value // e.g. "-" + "124"
+ kind = lit.Kind
+ } else {
+ lit, ok := arg.(*ast.BasicLit)
+ if !ok {
+ return nil, fmt.Errorf("literal value required for primitive type")
+ }
+ val, kind = lit.Value, lit.Kind
+ }
+
+ switch typ := idType.Name; typ {
+ case "string":
+ if kind != token.STRING {
+ return nil, fmt.Errorf("string literal value required for type string")
+ }
+ return strconv.Unquote(val)
+ case "byte", "rune":
+ if kind != token.CHAR {
+ return nil, fmt.Errorf("character literal required for byte/rune types")
+ }
+ n := len(val)
+ if n < 2 {
+ return nil, fmt.Errorf("malformed character literal, missing single quotes")
+ }
+ code, _, _, err := strconv.UnquoteChar(val[1:n-1], '\'')
+ if err != nil {
+ return nil, err
+ }
+ if typ == "rune" {
+ return code, nil
+ }
+ if code >= 256 {
+ return nil, fmt.Errorf("can only encode single byte to a byte type")
+ }
+ return byte(code), nil
+ case "int", "int8", "int16", "int32", "int64":
+ if kind != token.INT {
+ return nil, fmt.Errorf("integer literal required for int types")
+ }
+ return parseInt(val, typ)
+ case "uint", "uint8", "uint16", "uint32", "uint64":
+ if kind != token.INT {
+ return nil, fmt.Errorf("integer literal required for uint types")
+ }
+ return parseUint(val, typ)
+ case "float32":
+ if kind != token.FLOAT && kind != token.INT {
+ return nil, fmt.Errorf("float or integer literal required for float32 type")
+ }
+ v, err := strconv.ParseFloat(val, 32)
+ return float32(v), err
+ case "float64":
+ if kind != token.FLOAT && kind != token.INT {
+ return nil, fmt.Errorf("float or integer literal required for float64 type")
+ }
+ return strconv.ParseFloat(val, 64)
+ default:
+ return nil, fmt.Errorf("expected []byte or primitive type")
+ }
+}
+
+// parseInt returns an integer of value val and type typ.
+func parseInt(val, typ string) (interface{}, error) {
+ switch typ {
+ case "int":
+ return strconv.Atoi(val)
+ case "int8":
+ i, err := strconv.ParseInt(val, 10, 8)
+ return int8(i), err
+ case "int16":
+ i, err := strconv.ParseInt(val, 10, 16)
+ return int16(i), err
+ case "int32":
+ i, err := strconv.ParseInt(val, 10, 32)
+ return int32(i), err
+ case "int64":
+ return strconv.ParseInt(val, 10, 64)
+ default:
+ panic("unreachable")
+ }
+}
+
+// parseInt returns an unsigned integer of value val and type typ.
+func parseUint(val, typ string) (interface{}, error) {
+ switch typ {
+ case "uint":
+ i, err := strconv.ParseUint(val, 10, 0)
+ return uint(i), err
+ case "uint8":
+ i, err := strconv.ParseUint(val, 10, 8)
+ return uint8(i), err
+ case "uint16":
+ i, err := strconv.ParseUint(val, 10, 16)
+ return uint16(i), err
+ case "uint32":
+ i, err := strconv.ParseUint(val, 10, 32)
+ return uint32(i), err
+ case "uint64":
+ return strconv.ParseUint(val, 10, 64)
+ default:
+ panic("unreachable")
+ }
+}
diff --git a/src/internal/fuzz/encoding_test.go b/src/internal/fuzz/encoding_test.go
new file mode 100644
index 0000000..b429d42
--- /dev/null
+++ b/src/internal/fuzz/encoding_test.go
@@ -0,0 +1,172 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+import (
+ "strconv"
+ "strings"
+ "testing"
+)
+
+func TestUnmarshalMarshal(t *testing.T) {
+ var tests = []struct {
+ in string
+ ok bool
+ }{
+ {
+ in: "int(1234)",
+ ok: false, // missing version
+ },
+ {
+ in: `go test fuzz v1
+string("a"bcad")`,
+ ok: false, // malformed
+ },
+ {
+ in: `go test fuzz v1
+int()`,
+ ok: false, // empty value
+ },
+ {
+ in: `go test fuzz v1
+uint(-32)`,
+ ok: false, // invalid negative uint
+ },
+ {
+ in: `go test fuzz v1
+int8(1234456)`,
+ ok: false, // int8 too large
+ },
+ {
+ in: `go test fuzz v1
+int(20*5)`,
+ ok: false, // expression in int value
+ },
+ {
+ in: `go test fuzz v1
+int(--5)`,
+ ok: false, // expression in int value
+ },
+ {
+ in: `go test fuzz v1
+bool(0)`,
+ ok: false, // malformed bool
+ },
+ {
+ in: `go test fuzz v1
+byte('aa)`,
+ ok: false, // malformed byte
+ },
+ {
+ in: `go test fuzz v1
+byte('☃')`,
+ ok: false, // byte out of range
+ },
+ {
+ in: `go test fuzz v1
+string("has final newline")
+`,
+ ok: true, // has final newline
+ },
+ {
+ in: `go test fuzz v1
+string("extra")
+[]byte("spacing")
+ `,
+ ok: true, // extra spaces in the final newline
+ },
+ {
+ in: `go test fuzz v1
+float64(0)
+float32(0)`,
+ ok: true, // will be an integer literal since there is no decimal
+ },
+ {
+ in: `go test fuzz v1
+int(-23)
+int8(-2)
+int64(2342425)
+uint(1)
+uint16(234)
+uint32(352342)
+uint64(123)
+rune('œ')
+byte('K')
+byte('ÿ')
+[]byte("hello¿")
+[]byte("a")
+bool(true)
+string("hello\\xbd\\xb2=\\xbc ⌘")
+float64(-12.5)
+float32(2.5)`,
+ ok: true,
+ },
+ }
+ for _, test := range tests {
+ t.Run(test.in, func(t *testing.T) {
+ vals, err := unmarshalCorpusFile([]byte(test.in))
+ if test.ok && err != nil {
+ t.Fatalf("unmarshal unexpected error: %v", err)
+ } else if !test.ok && err == nil {
+ t.Fatalf("unmarshal unexpected success")
+ }
+ if !test.ok {
+ return // skip the rest of the test
+ }
+ newB := marshalCorpusFile(vals...)
+ if err != nil {
+ t.Fatalf("marshal unexpected error: %v", err)
+ }
+ if newB[len(newB)-1] != '\n' {
+ t.Error("didn't write final newline to corpus file")
+ }
+ before, after := strings.TrimSpace(test.in), strings.TrimSpace(string(newB))
+ if before != after {
+ t.Errorf("values changed after unmarshal then marshal\nbefore: %q\nafter: %q", before, after)
+ }
+ })
+ }
+}
+
+// BenchmarkMarshalCorpusFile measures the time it takes to serialize byte
+// slices of various sizes to a corpus file. The slice contains a repeating
+// sequence of bytes 0-255 to mix escaped and non-escaped characters.
+func BenchmarkMarshalCorpusFile(b *testing.B) {
+ buf := make([]byte, 1024*1024)
+ for i := 0; i < len(buf); i++ {
+ buf[i] = byte(i)
+ }
+
+ for sz := 1; sz <= len(buf); sz <<= 1 {
+ sz := sz
+ b.Run(strconv.Itoa(sz), func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ b.SetBytes(int64(sz))
+ marshalCorpusFile(buf[:sz])
+ }
+ })
+ }
+}
+
+// BenchmarkUnmarshalCorpusfile measures the time it takes to deserialize
+// files encoding byte slices of various sizes. The slice contains a repeating
+// sequence of bytes 0-255 to mix escaped and non-escaped characters.
+func BenchmarkUnmarshalCorpusFile(b *testing.B) {
+ buf := make([]byte, 1024*1024)
+ for i := 0; i < len(buf); i++ {
+ buf[i] = byte(i)
+ }
+
+ for sz := 1; sz <= len(buf); sz <<= 1 {
+ sz := sz
+ data := marshalCorpusFile(buf[:sz])
+ b.Run(strconv.Itoa(sz), func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ b.SetBytes(int64(sz))
+ unmarshalCorpusFile(data)
+ }
+ })
+ }
+}
diff --git a/src/internal/fuzz/fuzz.go b/src/internal/fuzz/fuzz.go
new file mode 100644
index 0000000..2cd7ebb
--- /dev/null
+++ b/src/internal/fuzz/fuzz.go
@@ -0,0 +1,1020 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package fuzz provides common fuzzing functionality for tests built with
+// "go test" and for programs that use fuzzing functionality in the testing
+// package.
+package fuzz
+
+import (
+ "context"
+ "crypto/sha256"
+ "errors"
+ "fmt"
+ "io"
+ "io/ioutil"
+ "math/bits"
+ "os"
+ "path/filepath"
+ "reflect"
+ "runtime"
+ "strings"
+ "sync"
+ "time"
+)
+
+// CoordinateFuzzingOpts is a set of arguments for CoordinateFuzzing.
+// The zero value is valid for each field unless specified otherwise.
+type CoordinateFuzzingOpts struct {
+ // Log is a writer for logging progress messages and warnings.
+ // If nil, io.Discard will be used instead.
+ Log io.Writer
+
+ // Timeout is the amount of wall clock time to spend fuzzing after the corpus
+ // has loaded. If zero, there will be no time limit.
+ Timeout time.Duration
+
+ // Limit is the number of random values to generate and test. If zero,
+ // there will be no limit on the number of generated values.
+ Limit int64
+
+ // MinimizeTimeout is the amount of wall clock time to spend minimizing
+ // after discovering a crasher. If zero, there will be no time limit. If
+ // MinimizeTimeout and MinimizeLimit are both zero, then minimization will
+ // be disabled.
+ MinimizeTimeout time.Duration
+
+ // MinimizeLimit is the maximum number of calls to the fuzz function to be
+ // made while minimizing after finding a crash. If zero, there will be no
+ // limit. Calls to the fuzz function made when minimizing also count toward
+ // Limit. If MinimizeTimeout and MinimizeLimit are both zero, then
+ // minimization will be disabled.
+ MinimizeLimit int64
+
+ // parallel is the number of worker processes to run in parallel. If zero,
+ // CoordinateFuzzing will run GOMAXPROCS workers.
+ Parallel int
+
+ // Seed is a list of seed values added by the fuzz target with testing.F.Add
+ // and in testdata.
+ Seed []CorpusEntry
+
+ // Types is the list of types which make up a corpus entry.
+ // Types must be set and must match values in Seed.
+ Types []reflect.Type
+
+ // CorpusDir is a directory where files containing values that crash the
+ // code being tested may be written. CorpusDir must be set.
+ CorpusDir string
+
+ // CacheDir is a directory containing additional "interesting" values.
+ // The fuzzer may derive new values from these, and may write new values here.
+ CacheDir string
+}
+
+// CoordinateFuzzing creates several worker processes and communicates with
+// them to test random inputs that could trigger crashes and expose bugs.
+// The worker processes run the same binary in the same directory with the
+// same environment variables as the coordinator process. Workers also run
+// with the same arguments as the coordinator, except with the -test.fuzzworker
+// flag prepended to the argument list.
+//
+// If a crash occurs, the function will return an error containing information
+// about the crash, which can be reported to the user.
+func CoordinateFuzzing(ctx context.Context, opts CoordinateFuzzingOpts) (err error) {
+ if err := ctx.Err(); err != nil {
+ return err
+ }
+ if opts.Log == nil {
+ opts.Log = io.Discard
+ }
+ if opts.Parallel == 0 {
+ opts.Parallel = runtime.GOMAXPROCS(0)
+ }
+ if opts.Limit > 0 && int64(opts.Parallel) > opts.Limit {
+ // Don't start more workers than we need.
+ opts.Parallel = int(opts.Limit)
+ }
+
+ c, err := newCoordinator(opts)
+ if err != nil {
+ return err
+ }
+
+ if opts.Timeout > 0 {
+ var cancel func()
+ ctx, cancel = context.WithTimeout(ctx, opts.Timeout)
+ defer cancel()
+ }
+
+ // fuzzCtx is used to stop workers, for example, after finding a crasher.
+ fuzzCtx, cancelWorkers := context.WithCancel(ctx)
+ defer cancelWorkers()
+ doneC := ctx.Done()
+
+ // stop is called when a worker encounters a fatal error.
+ var fuzzErr error
+ stopping := false
+ stop := func(err error) {
+ if err == fuzzCtx.Err() || isInterruptError(err) {
+ // Suppress cancellation errors and terminations due to SIGINT.
+ // The messages are not helpful since either the user triggered the error
+ // (with ^C) or another more helpful message will be printed (a crasher).
+ err = nil
+ }
+ if err != nil && (fuzzErr == nil || fuzzErr == ctx.Err()) {
+ fuzzErr = err
+ }
+ if stopping {
+ return
+ }
+ stopping = true
+ cancelWorkers()
+ doneC = nil
+ }
+
+ // Ensure that any crash we find is written to the corpus, even if an error
+ // or interruption occurs while minimizing it.
+ var crashMinimizing *fuzzResult
+ crashWritten := false
+ defer func() {
+ if crashMinimizing == nil || crashWritten {
+ return
+ }
+ fileName, werr := writeToCorpus(crashMinimizing.entry.Data, opts.CorpusDir)
+ if werr != nil {
+ err = fmt.Errorf("%w\n%v", err, werr)
+ return
+ }
+ if err == nil {
+ err = &crashError{
+ name: filepath.Base(fileName),
+ err: errors.New(crashMinimizing.crasherMsg),
+ }
+ }
+ }()
+
+ // Start workers.
+ // TODO(jayconrod): do we want to support fuzzing different binaries?
+ dir := "" // same as self
+ binPath := os.Args[0]
+ args := append([]string{"-test.fuzzworker"}, os.Args[1:]...)
+ env := os.Environ() // same as self
+
+ errC := make(chan error)
+ workers := make([]*worker, opts.Parallel)
+ for i := range workers {
+ var err error
+ workers[i], err = newWorker(c, dir, binPath, args, env)
+ if err != nil {
+ return err
+ }
+ }
+ for i := range workers {
+ w := workers[i]
+ go func() {
+ err := w.coordinate(fuzzCtx)
+ if fuzzCtx.Err() != nil || isInterruptError(err) {
+ err = nil
+ }
+ cleanErr := w.cleanup()
+ if err == nil {
+ err = cleanErr
+ }
+ errC <- err
+ }()
+ }
+
+ // Main event loop.
+ // Do not return until all workers have terminated. We avoid a deadlock by
+ // receiving messages from workers even after ctx is cancelled.
+ activeWorkers := len(workers)
+ statTicker := time.NewTicker(3 * time.Second)
+ defer statTicker.Stop()
+ defer c.logStats()
+
+ c.logStats()
+ for {
+ var inputC chan fuzzInput
+ input, ok := c.peekInput()
+ if ok && crashMinimizing == nil && !stopping {
+ inputC = c.inputC
+ }
+
+ var minimizeC chan fuzzMinimizeInput
+ minimizeInput, ok := c.peekMinimizeInput()
+ if ok && !stopping {
+ minimizeC = c.minimizeC
+ }
+
+ select {
+ case <-doneC:
+ // Interrupted, cancelled, or timed out.
+ // stop sets doneC to nil so we don't busy wait here.
+ stop(ctx.Err())
+
+ case err := <-errC:
+ // A worker terminated, possibly after encountering a fatal error.
+ stop(err)
+ activeWorkers--
+ if activeWorkers == 0 {
+ return fuzzErr
+ }
+
+ case result := <-c.resultC:
+ // Received response from worker.
+ if stopping {
+ break
+ }
+ c.updateStats(result)
+ if c.opts.Limit > 0 && c.count >= c.opts.Limit {
+ stop(nil)
+ }
+
+ if result.crasherMsg != "" {
+ if c.warmupRun() && result.entry.IsSeed {
+ fmt.Fprintf(c.opts.Log, "found a crash while testing seed corpus entry: %q\n", result.entry.Parent)
+ stop(errors.New(result.crasherMsg))
+ break
+ }
+ if c.canMinimize() && !result.minimizeAttempted {
+ if crashMinimizing != nil {
+ // This crash is not minimized, and another crash is being minimized.
+ // Ignore this one and wait for the other one to finish.
+ break
+ }
+ // Found a crasher but haven't yet attempted to minimize it.
+ // Send it back to a worker for minimization. Disable inputC so
+ // other workers don't continue fuzzing.
+ crashMinimizing = &result
+ fmt.Fprintf(c.opts.Log, "fuzz: found a %d-byte crash input; minimizing...\n", len(result.entry.Data))
+ c.queueForMinimization(result, nil)
+ } else if !crashWritten {
+ // Found a crasher that's either minimized or not minimizable.
+ // Write to corpus and stop.
+ fileName, err := writeToCorpus(result.entry.Data, opts.CorpusDir)
+ if err == nil {
+ crashWritten = true
+ err = &crashError{
+ name: filepath.Base(fileName),
+ err: errors.New(result.crasherMsg),
+ }
+ }
+ if printDebugInfo() {
+ fmt.Fprintf(
+ c.opts.Log,
+ "DEBUG new crasher, elapsed: %s, id: %s, parent: %s, gen: %d, size: %d, exec time: %s\n",
+ c.elapsed(),
+ fileName,
+ result.entry.Parent,
+ result.entry.Generation,
+ len(result.entry.Data),
+ result.entryDuration,
+ )
+ }
+ stop(err)
+ }
+ } else if result.coverageData != nil {
+ if c.warmupRun() {
+ if printDebugInfo() {
+ fmt.Fprintf(
+ c.opts.Log,
+ "DEBUG processed an initial input, elapsed: %s, id: %s, new bits: %d, size: %d, exec time: %s\n",
+ c.elapsed(),
+ result.entry.Parent,
+ countBits(diffCoverage(c.coverageMask, result.coverageData)),
+ len(result.entry.Data),
+ result.entryDuration,
+ )
+ }
+ c.updateCoverage(result.coverageData)
+ c.warmupInputCount--
+ if printDebugInfo() && c.warmupInputCount == 0 {
+ fmt.Fprintf(
+ c.opts.Log,
+ "DEBUG finished processing input corpus, elapsed: %s, entries: %d, initial coverage bits: %d\n",
+ c.elapsed(),
+ len(c.corpus.entries),
+ countBits(c.coverageMask),
+ )
+ }
+ } else if keepCoverage := diffCoverage(c.coverageMask, result.coverageData); keepCoverage != nil {
+ // Found a value that expanded coverage.
+ // It's not a crasher, but we may want to add it to the on-disk
+ // corpus and prioritize it for future fuzzing.
+ // TODO(jayconrod, katiehockman): Prioritize fuzzing these
+ // values which expanded coverage, perhaps based on the
+ // number of new edges that this result expanded.
+ // TODO(jayconrod, katiehockman): Don't write a value that's already
+ // in the corpus.
+ if !result.minimizeAttempted && crashMinimizing == nil && c.canMinimize() {
+ // Send back to workers to find a smaller value that preserves
+ // at least one new coverage bit.
+ c.queueForMinimization(result, keepCoverage)
+ } else {
+ // Update the coordinator's coverage mask and save the value.
+ inputSize := len(result.entry.Data)
+ if opts.CacheDir != "" {
+ filename, err := writeToCorpus(result.entry.Data, opts.CacheDir)
+ if err != nil {
+ stop(err)
+ }
+ result.entry.Data = nil
+ result.entry.Name = filename
+ }
+ c.updateCoverage(keepCoverage)
+ c.corpus.entries = append(c.corpus.entries, result.entry)
+ c.inputQueue.enqueue(result.entry)
+ c.interestingCount++
+ if printDebugInfo() {
+ fmt.Fprintf(
+ c.opts.Log,
+ "DEBUG new interesting input, elapsed: %s, id: %s, parent: %s, gen: %d, new bits: %d, total bits: %d, size: %d, exec time: %s\n",
+ c.elapsed(),
+ result.entry.Name,
+ result.entry.Parent,
+ result.entry.Generation,
+ countBits(keepCoverage),
+ countBits(c.coverageMask),
+ inputSize,
+ result.entryDuration,
+ )
+ }
+ }
+ } else {
+ if printDebugInfo() {
+ fmt.Fprintf(
+ c.opts.Log,
+ "DEBUG worker reported interesting input that doesn't expand coverage, elapsed: %s, id: %s, parent: %s, minimized: %t\n",
+ c.elapsed(),
+ result.entry.Name,
+ result.entry.Parent,
+ result.minimizeAttempted,
+ )
+ }
+ }
+ } else if c.warmupRun() {
+ // No error or coverage data was reported for this input during
+ // warmup, so continue processing results.
+ c.warmupInputCount--
+ if printDebugInfo() && c.warmupInputCount == 0 {
+ fmt.Fprintf(
+ c.opts.Log,
+ "DEBUG finished testing-only phase, elapsed: %s, entries: %d\n",
+ time.Since(c.startTime),
+ len(c.corpus.entries),
+ )
+ }
+ }
+
+ case inputC <- input:
+ // Sent the next input to a worker.
+ c.sentInput(input)
+
+ case minimizeC <- minimizeInput:
+ // Sent the next input for minimization to a worker.
+ c.sentMinimizeInput(minimizeInput)
+
+ case <-statTicker.C:
+ c.logStats()
+ }
+ }
+
+ // TODO(jayconrod,katiehockman): if a crasher can't be written to the corpus,
+ // write to the cache instead.
+}
+
+// crashError wraps a crasher written to the seed corpus. It saves the name
+// of the file where the input causing the crasher was saved. The testing
+// framework uses this to report a command to re-run that specific input.
+type crashError struct {
+ name string
+ err error
+}
+
+func (e *crashError) Error() string {
+ return e.err.Error()
+}
+
+func (e *crashError) Unwrap() error {
+ return e.err
+}
+
+func (e *crashError) CrashName() string {
+ return e.name
+}
+
+type corpus struct {
+ entries []CorpusEntry
+}
+
+// CorpusEntry represents an individual input for fuzzing.
+//
+// We must use an equivalent type in the testing and testing/internal/testdeps
+// packages, but testing can't import this package directly, and we don't want
+// to export this type from testing. Instead, we use the same struct type and
+// use a type alias (not a defined type) for convenience.
+type CorpusEntry = struct {
+ Parent string
+
+ // Name is the name of the corpus file, if the entry was loaded from the
+ // seed corpus. It can be used with -run. For entries added with f.Add and
+ // entries generated by the mutator, Name is empty and Data is populated.
+ Name string
+
+ // Data is the raw input data. Data should only be populated for initial
+ // seed values added with f.Add. For on-disk corpus files, Data will
+ // be nil.
+ Data []byte
+
+ // Values is the unmarshaled values from a corpus file.
+ Values []interface{}
+
+ Generation int
+
+ // IsSeed indicates whether this entry is part of the seed corpus.
+ IsSeed bool
+}
+
+// Data returns the raw input bytes, either from the data struct field,
+// or from disk.
+func CorpusEntryData(ce CorpusEntry) ([]byte, error) {
+ if ce.Data != nil {
+ return ce.Data, nil
+ }
+
+ return os.ReadFile(ce.Name)
+}
+
+type fuzzInput struct {
+ // entry is the value to test initially. The worker will randomly mutate
+ // values from this starting point.
+ entry CorpusEntry
+
+ // timeout is the time to spend fuzzing variations of this input,
+ // not including starting or cleaning up.
+ timeout time.Duration
+
+ // limit is the maximum number of calls to the fuzz function the worker may
+ // make. The worker may make fewer calls, for example, if it finds an
+ // error early. If limit is zero, there is no limit on calls to the
+ // fuzz function.
+ limit int64
+
+ // warmup indicates whether this is a warmup input before fuzzing begins. If
+ // true, the input should not be fuzzed.
+ warmup bool
+
+ // coverageData reflects the coordinator's current coverageMask.
+ coverageData []byte
+}
+
+type fuzzResult struct {
+ // entry is an interesting value or a crasher.
+ entry CorpusEntry
+
+ // crasherMsg is an error message from a crash. It's "" if no crash was found.
+ crasherMsg string
+
+ // minimizeAttempted is true if the worker attempted to minimize this input.
+ // The worker may or may not have succeeded.
+ minimizeAttempted bool
+
+ // coverageData is set if the worker found new coverage.
+ coverageData []byte
+
+ // limit is the number of values the coordinator asked the worker
+ // to test. 0 if there was no limit.
+ limit int64
+
+ // count is the number of values the worker actually tested.
+ count int64
+
+ // totalDuration is the time the worker spent testing inputs.
+ totalDuration time.Duration
+
+ // entryDuration is the time the worker spent execution an interesting result
+ entryDuration time.Duration
+}
+
+type fuzzMinimizeInput struct {
+ // entry is an interesting value or crasher to minimize.
+ entry CorpusEntry
+
+ // crasherMsg is an error message from a crash. It's "" if no crash was found.
+ // If set, the worker will attempt to find a smaller input that also produces
+ // an error, though not necessarily the same error.
+ crasherMsg string
+
+ // limit is the maximum number of calls to the fuzz function the worker may
+ // make. The worker may make fewer calls, for example, if it can't reproduce
+ // an error. If limit is zero, there is no limit on calls to the fuzz function.
+ limit int64
+
+ // timeout is the time to spend minimizing this input.
+ // A zero timeout means no limit.
+ timeout time.Duration
+
+ // keepCoverage is a set of coverage bits that entry found that were not in
+ // the coordinator's combined set. When minimizing, the worker should find an
+ // input that preserves at least one of these bits. keepCoverage is nil for
+ // crashing inputs.
+ keepCoverage []byte
+}
+
+// coordinator holds channels that workers can use to communicate with
+// the coordinator.
+type coordinator struct {
+ opts CoordinateFuzzingOpts
+
+ // startTime is the time we started the workers after loading the corpus.
+ // Used for logging.
+ startTime time.Time
+
+ // inputC is sent values to fuzz by the coordinator. Any worker may receive
+ // values from this channel. Workers send results to resultC.
+ inputC chan fuzzInput
+
+ // minimizeC is sent values to minimize by the coordinator. Any worker may
+ // receive values from this channel. Workers send results to resultC.
+ minimizeC chan fuzzMinimizeInput
+
+ // resultC is sent results of fuzzing by workers. The coordinator
+ // receives these. Multiple types of messages are allowed.
+ resultC chan fuzzResult
+
+ // count is the number of values fuzzed so far.
+ count int64
+
+ // interestingCount is the number of unique interesting values which have
+ // been found this execution.
+ interestingCount int64
+
+ // warmupInputCount is the number of entries in the corpus which still need
+ // to be received from workers to run once during warmup, but not fuzz. This
+ // could be for coverage data, or only for the purposes of verifying that
+ // the seed corpus doesn't have any crashers. See warmupRun.
+ warmupInputCount int
+
+ // duration is the time spent fuzzing inside workers, not counting time
+ // starting up or tearing down.
+ duration time.Duration
+
+ // countWaiting is the number of fuzzing executions the coordinator is
+ // waiting on workers to complete.
+ countWaiting int64
+
+ // corpus is a set of interesting values, including the seed corpus and
+ // generated values that workers reported as interesting.
+ corpus corpus
+
+ // minimizationAllowed is true if one or more of the types of fuzz
+ // function's parameters can be minimized, and either the limit or duration
+ // for minimization is non-zero.
+ minimizationAllowed bool
+
+ // inputQueue is a queue of inputs that workers should try fuzzing. This is
+ // initially populated from the seed corpus and cached inputs. More inputs
+ // may be added as new coverage is discovered.
+ inputQueue queue
+
+ // minimizeQueue is a queue of inputs that caused errors or exposed new
+ // coverage. Workers should attempt to find smaller inputs that do the
+ // same thing.
+ minimizeQueue queue
+
+ // coverageMask aggregates coverage that was found for all inputs in the
+ // corpus. Each byte represents a single basic execution block. Each set bit
+ // within the byte indicates that an input has triggered that block at least
+ // 1 << n times, where n is the position of the bit in the byte. For example, a
+ // value of 12 indicates that separate inputs have triggered this block
+ // between 4-7 times and 8-15 times.
+ coverageMask []byte
+}
+
+func newCoordinator(opts CoordinateFuzzingOpts) (*coordinator, error) {
+ // Make sure all of the seed corpus given by f.Add has marshalled data.
+ for i := range opts.Seed {
+ if opts.Seed[i].Data == nil && opts.Seed[i].Values != nil {
+ opts.Seed[i].Data = marshalCorpusFile(opts.Seed[i].Values...)
+ }
+ }
+ corpus, err := readCache(opts.Seed, opts.Types, opts.CacheDir)
+ if err != nil {
+ return nil, err
+ }
+ c := &coordinator{
+ opts: opts,
+ startTime: time.Now(),
+ inputC: make(chan fuzzInput),
+ minimizeC: make(chan fuzzMinimizeInput),
+ resultC: make(chan fuzzResult),
+ corpus: corpus,
+ }
+ if opts.MinimizeLimit > 0 || opts.MinimizeTimeout > 0 {
+ for _, t := range opts.Types {
+ if isMinimizable(t) {
+ c.minimizationAllowed = true
+ break
+ }
+ }
+ }
+
+ covSize := len(coverage())
+ if covSize == 0 {
+ fmt.Fprintf(c.opts.Log, "warning: the test binary was not built with coverage instrumentation, so fuzzing will run without coverage guidance and may be inefficient\n")
+ // Even though a coverage-only run won't occur, we should still run all
+ // of the seed corpus to make sure there are no existing failures before
+ // we start fuzzing.
+ c.warmupInputCount = len(c.opts.Seed)
+ for _, e := range c.opts.Seed {
+ c.inputQueue.enqueue(e)
+ }
+ } else {
+ c.warmupInputCount = len(c.corpus.entries)
+ for _, e := range c.corpus.entries {
+ c.inputQueue.enqueue(e)
+ }
+ // Set c.coverageMask to a clean []byte full of zeros.
+ c.coverageMask = make([]byte, covSize)
+ }
+
+ if len(c.corpus.entries) == 0 {
+ fmt.Fprintf(c.opts.Log, "warning: starting with empty corpus\n")
+ var vals []interface{}
+ for _, t := range opts.Types {
+ vals = append(vals, zeroValue(t))
+ }
+ data := marshalCorpusFile(vals...)
+ h := sha256.Sum256(data)
+ name := fmt.Sprintf("%x", h[:4])
+ c.corpus.entries = append(c.corpus.entries, CorpusEntry{Name: name, Data: data})
+ }
+
+ return c, nil
+}
+
+func (c *coordinator) updateStats(result fuzzResult) {
+ c.count += result.count
+ c.countWaiting -= result.limit
+ c.duration += result.totalDuration
+}
+
+func (c *coordinator) logStats() {
+ elapsed := c.elapsed()
+ if c.warmupRun() {
+ if coverageEnabled {
+ fmt.Fprintf(c.opts.Log, "gathering baseline coverage, elapsed: %s, workers: %d, left: %d\n", elapsed, c.opts.Parallel, c.warmupInputCount)
+ } else {
+ fmt.Fprintf(c.opts.Log, "testing seed corpus, elapsed: %s, workers: %d, left: %d\n", elapsed, c.opts.Parallel, c.warmupInputCount)
+ }
+ } else {
+ rate := float64(c.count) / time.Since(c.startTime).Seconds() // be more precise here
+ fmt.Fprintf(c.opts.Log, "fuzz: elapsed: %s, execs: %d (%.0f/sec), workers: %d, interesting: %d\n", elapsed, c.count, rate, c.opts.Parallel, c.interestingCount)
+ }
+}
+
+// peekInput returns the next value that should be sent to workers.
+// If the number of executions is limited, the returned value includes
+// a limit for one worker. If there are no executions left, peekInput returns
+// a zero value and false.
+//
+// peekInput doesn't actually remove the input from the queue. The caller
+// must call sentInput after sending the input.
+//
+// If the input queue is empty and the coverage/testing-only run has completed,
+// queue refills it from the corpus.
+func (c *coordinator) peekInput() (fuzzInput, bool) {
+ if c.opts.Limit > 0 && c.count+c.countWaiting >= c.opts.Limit {
+ // Already making the maximum number of calls to the fuzz function.
+ // Don't send more inputs right now.
+ return fuzzInput{}, false
+ }
+ if c.inputQueue.len == 0 {
+ if c.warmupInputCount > 0 {
+ // Wait for coverage/testing-only run to finish before sending more
+ // inputs.
+ return fuzzInput{}, false
+ }
+ c.refillInputQueue()
+ }
+
+ entry, ok := c.inputQueue.peek()
+ if !ok {
+ panic("input queue empty after refill")
+ }
+ input := fuzzInput{
+ entry: entry.(CorpusEntry),
+ timeout: workerFuzzDuration,
+ warmup: c.warmupRun(),
+ }
+ if c.coverageMask != nil {
+ input.coverageData = make([]byte, len(c.coverageMask))
+ copy(input.coverageData, c.coverageMask)
+ }
+ if input.warmup {
+ // No fuzzing will occur, but it should count toward the limit set by
+ // -fuzztime.
+ input.limit = 1
+ return input, true
+ }
+
+ if c.opts.Limit > 0 {
+ input.limit = c.opts.Limit / int64(c.opts.Parallel)
+ if c.opts.Limit%int64(c.opts.Parallel) > 0 {
+ input.limit++
+ }
+ remaining := c.opts.Limit - c.count - c.countWaiting
+ if input.limit > remaining {
+ input.limit = remaining
+ }
+ }
+ return input, true
+}
+
+// sentInput updates internal counters after an input is sent to c.inputC.
+func (c *coordinator) sentInput(input fuzzInput) {
+ c.inputQueue.dequeue()
+ c.countWaiting += input.limit
+}
+
+// refillInputQueue refills the input queue from the corpus after it becomes
+// empty.
+func (c *coordinator) refillInputQueue() {
+ for _, e := range c.corpus.entries {
+ c.inputQueue.enqueue(e)
+ }
+}
+
+// queueForMinimization creates a fuzzMinimizeInput from result and adds it
+// to the minimization queue to be sent to workers.
+func (c *coordinator) queueForMinimization(result fuzzResult, keepCoverage []byte) {
+ if result.crasherMsg != "" {
+ c.minimizeQueue.clear()
+ }
+
+ input := fuzzMinimizeInput{
+ entry: result.entry,
+ crasherMsg: result.crasherMsg,
+ keepCoverage: keepCoverage,
+ }
+ c.minimizeQueue.enqueue(input)
+}
+
+// peekMinimizeInput returns the next input that should be sent to workers for
+// minimization.
+func (c *coordinator) peekMinimizeInput() (fuzzMinimizeInput, bool) {
+ if !c.canMinimize() {
+ // Already making the maximum number of calls to the fuzz function.
+ // Don't send more inputs right now.
+ return fuzzMinimizeInput{}, false
+ }
+ v, ok := c.minimizeQueue.peek()
+ if !ok {
+ return fuzzMinimizeInput{}, false
+ }
+ input := v.(fuzzMinimizeInput)
+
+ if c.opts.MinimizeTimeout > 0 {
+ input.timeout = c.opts.MinimizeTimeout
+ }
+ if c.opts.MinimizeLimit > 0 {
+ input.limit = c.opts.MinimizeLimit
+ } else if c.opts.Limit > 0 {
+ if input.crasherMsg != "" {
+ input.limit = c.opts.Limit
+ } else {
+ input.limit = c.opts.Limit / int64(c.opts.Parallel)
+ if c.opts.Limit%int64(c.opts.Parallel) > 0 {
+ input.limit++
+ }
+ }
+ }
+ remaining := c.opts.Limit - c.count - c.countWaiting
+ if input.limit > remaining {
+ input.limit = remaining
+ }
+ return input, true
+}
+
+// sentMinimizeInput removes an input from the minimization queue after it's
+// sent to minimizeC.
+func (c *coordinator) sentMinimizeInput(input fuzzMinimizeInput) {
+ c.minimizeQueue.dequeue()
+ c.countWaiting += input.limit
+}
+
+// warmupRun returns true while the coordinator is running inputs without
+// mutating them as a warmup before fuzzing. This could be to gather baseline
+// coverage data for entries in the corpus, or to test all of the seed corpus
+// for errors before fuzzing begins.
+//
+// The coordinator doesn't store coverage data in the cache with each input
+// because that data would be invalid when counter offsets in the test binary
+// change.
+//
+// When gathering coverage, the coordinator sends each entry to a worker to
+// gather coverage for that entry only, without fuzzing or minimizing. This
+// phase ends when all workers have finished, and the coordinator has a combined
+// coverage map.
+func (c *coordinator) warmupRun() bool {
+ return c.warmupInputCount > 0
+}
+
+// updateCoverage sets bits in c.coverageMask that are set in newCoverage.
+// updateCoverage returns the number of newly set bits. See the comment on
+// coverageMask for the format.
+func (c *coordinator) updateCoverage(newCoverage []byte) int {
+ if len(newCoverage) != len(c.coverageMask) {
+ panic(fmt.Sprintf("number of coverage counters changed at runtime: %d, expected %d", len(newCoverage), len(c.coverageMask)))
+ }
+ newBitCount := 0
+ for i := range newCoverage {
+ diff := newCoverage[i] &^ c.coverageMask[i]
+ newBitCount += bits.OnesCount8(diff)
+ c.coverageMask[i] |= newCoverage[i]
+ }
+ return newBitCount
+}
+
+// canMinimize returns whether the coordinator should attempt to find smaller
+// inputs that reproduce a crash or new coverage. It shouldn't do this if it
+// is in the warmup phase.
+func (c *coordinator) canMinimize() bool {
+ return c.minimizationAllowed &&
+ (c.opts.Limit == 0 || c.count+c.countWaiting < c.opts.Limit) &&
+ !c.warmupRun()
+}
+
+func (c *coordinator) elapsed() time.Duration {
+ return time.Since(c.startTime).Round(1 * time.Second)
+}
+
+// readCache creates a combined corpus from seed values and values in the cache
+// (in GOCACHE/fuzz).
+//
+// TODO(fuzzing): need a mechanism that can remove values that
+// aren't useful anymore, for example, because they have the wrong type.
+func readCache(seed []CorpusEntry, types []reflect.Type, cacheDir string) (corpus, error) {
+ var c corpus
+ c.entries = append(c.entries, seed...)
+ entries, err := ReadCorpus(cacheDir, types)
+ if err != nil {
+ if _, ok := err.(*MalformedCorpusError); !ok {
+ // It's okay if some files in the cache directory are malformed and
+ // are not included in the corpus, but fail if it's an I/O error.
+ return corpus{}, err
+ }
+ // TODO(jayconrod,katiehockman): consider printing some kind of warning
+ // indicating the number of files which were skipped because they are
+ // malformed.
+ }
+ c.entries = append(c.entries, entries...)
+ return c, nil
+}
+
+// MalformedCorpusError is an error found while reading the corpus from the
+// filesystem. All of the errors are stored in the errs list. The testing
+// framework uses this to report malformed files in testdata.
+type MalformedCorpusError struct {
+ errs []error
+}
+
+func (e *MalformedCorpusError) Error() string {
+ var msgs []string
+ for _, s := range e.errs {
+ msgs = append(msgs, s.Error())
+ }
+ return strings.Join(msgs, "\n")
+}
+
+// ReadCorpus reads the corpus from the provided dir. The returned corpus
+// entries are guaranteed to match the given types. Any malformed files will
+// be saved in a MalformedCorpusError and returned, along with the most recent
+// error.
+func ReadCorpus(dir string, types []reflect.Type) ([]CorpusEntry, error) {
+ files, err := ioutil.ReadDir(dir)
+ if os.IsNotExist(err) {
+ return nil, nil // No corpus to read
+ } else if err != nil {
+ return nil, fmt.Errorf("reading seed corpus from testdata: %v", err)
+ }
+ var corpus []CorpusEntry
+ var errs []error
+ for _, file := range files {
+ // TODO(jayconrod,katiehockman): determine when a file is a fuzzing input
+ // based on its name. We should only read files created by writeToCorpus.
+ // If we read ALL files, we won't be able to change the file format by
+ // changing the extension. We also won't be able to add files like
+ // README.txt explaining why the directory exists.
+ if file.IsDir() {
+ continue
+ }
+ filename := filepath.Join(dir, file.Name())
+ data, err := ioutil.ReadFile(filename)
+ if err != nil {
+ return nil, fmt.Errorf("failed to read corpus file: %v", err)
+ }
+ var vals []interface{}
+ vals, err = readCorpusData(data, types)
+ if err != nil {
+ errs = append(errs, fmt.Errorf("%q: %v", filename, err))
+ continue
+ }
+ corpus = append(corpus, CorpusEntry{Name: filename, Values: vals})
+ }
+ if len(errs) > 0 {
+ return corpus, &MalformedCorpusError{errs: errs}
+ }
+ return corpus, nil
+}
+
+func readCorpusData(data []byte, types []reflect.Type) ([]interface{}, error) {
+ vals, err := unmarshalCorpusFile(data)
+ if err != nil {
+ return nil, fmt.Errorf("unmarshal: %v", err)
+ }
+ if err = CheckCorpus(vals, types); err != nil {
+ return nil, err
+ }
+ return vals, nil
+}
+
+// CheckCorpus verifies that the types in vals match the expected types
+// provided.
+func CheckCorpus(vals []interface{}, types []reflect.Type) error {
+ if len(vals) != len(types) {
+ return fmt.Errorf("wrong number of values in corpus entry: %d, want %d", len(vals), len(types))
+ }
+ for i := range types {
+ if reflect.TypeOf(vals[i]) != types[i] {
+ return fmt.Errorf("mismatched types in corpus entry: %v, want %v", vals, types)
+ }
+ }
+ return nil
+}
+
+// writeToCorpus atomically writes the given bytes to a new file in testdata.
+// If the directory does not exist, it will create one. If the file already
+// exists, writeToCorpus will not rewrite it. writeToCorpus returns the
+// file's name, or an error if it failed.
+func writeToCorpus(b []byte, dir string) (name string, err error) {
+ sum := fmt.Sprintf("%x", sha256.Sum256(b))
+ name = filepath.Join(dir, sum)
+ if err := os.MkdirAll(dir, 0777); err != nil {
+ return "", err
+ }
+ if err := ioutil.WriteFile(name, b, 0666); err != nil {
+ os.Remove(name) // remove partially written file
+ return "", err
+ }
+ return name, nil
+}
+
+func zeroValue(t reflect.Type) interface{} {
+ for _, v := range zeroVals {
+ if reflect.TypeOf(v) == t {
+ return v
+ }
+ }
+ panic(fmt.Sprintf("unsupported type: %v", t))
+}
+
+var zeroVals []interface{} = []interface{}{
+ []byte(""),
+ string(""),
+ false,
+ byte(0),
+ rune(0),
+ float32(0),
+ float64(0),
+ int(0),
+ int8(0),
+ int16(0),
+ int32(0),
+ int64(0),
+ uint(0),
+ uint8(0),
+ uint16(0),
+ uint32(0),
+ uint64(0),
+}
+
+var (
+ debugInfo bool
+ debugInfoOnce sync.Once
+)
+
+func printDebugInfo() bool {
+ debugInfoOnce.Do(func() {
+ debug := strings.Split(os.Getenv("GODEBUG"), ",")
+ for _, f := range debug {
+ if f == "fuzzdebug=1" {
+ debugInfo = true
+ break
+ }
+ }
+ })
+ return debugInfo
+}
diff --git a/src/internal/fuzz/mem.go b/src/internal/fuzz/mem.go
new file mode 100644
index 0000000..ccd4da2
--- /dev/null
+++ b/src/internal/fuzz/mem.go
@@ -0,0 +1,134 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+import (
+ "fmt"
+ "io/ioutil"
+ "os"
+ "unsafe"
+)
+
+// sharedMem manages access to a region of virtual memory mapped from a file,
+// shared between multiple processes. The region includes space for a header and
+// a value of variable length.
+//
+// When fuzzing, the coordinator creates a sharedMem from a temporary file for
+// each worker. This buffer is used to pass values to fuzz between processes.
+// Care must be taken to manage access to shared memory across processes;
+// sharedMem provides no synchronization on its own. See workerComm for an
+// explanation.
+type sharedMem struct {
+ // f is the file mapped into memory.
+ f *os.File
+
+ // region is the mapped region of virtual memory for f. The content of f may
+ // be read or written through this slice.
+ region []byte
+
+ // removeOnClose is true if the file should be deleted by Close.
+ removeOnClose bool
+
+ // sys contains OS-specific information.
+ sys sharedMemSys
+}
+
+// sharedMemHeader stores metadata in shared memory.
+type sharedMemHeader struct {
+ // count is the number of times the worker has called the fuzz function.
+ // May be reset by coordinator.
+ count int64
+
+ // valueLen is the length of the value that was last fuzzed.
+ valueLen int
+
+ // randState and randInc hold the state of a pseudo-random number generator.
+ randState, randInc uint64
+}
+
+// sharedMemSize returns the size needed for a shared memory buffer that can
+// contain values of the given size.
+func sharedMemSize(valueSize int) int {
+ // TODO(jayconrod): set a reasonable maximum size per platform.
+ return int(unsafe.Sizeof(sharedMemHeader{})) + valueSize
+}
+
+// sharedMemTempFile creates a new temporary file of the given size, then maps
+// it into memory. The file will be removed when the Close method is called.
+func sharedMemTempFile(size int) (m *sharedMem, err error) {
+ // Create a temporary file.
+ f, err := ioutil.TempFile("", "fuzz-*")
+ if err != nil {
+ return nil, err
+ }
+ defer func() {
+ if err != nil {
+ f.Close()
+ os.Remove(f.Name())
+ }
+ }()
+
+ // Resize it to the correct size.
+ totalSize := sharedMemSize(size)
+ if err := f.Truncate(int64(totalSize)); err != nil {
+ return nil, err
+ }
+
+ // Map the file into memory.
+ removeOnClose := true
+ return sharedMemMapFile(f, totalSize, removeOnClose)
+}
+
+// header returns a pointer to metadata within the shared memory region.
+func (m *sharedMem) header() *sharedMemHeader {
+ return (*sharedMemHeader)(unsafe.Pointer(&m.region[0]))
+}
+
+// valueRef returns the value currently stored in shared memory. The returned
+// slice points to shared memory; it is not a copy.
+func (m *sharedMem) valueRef() []byte {
+ length := m.header().valueLen
+ valueOffset := int(unsafe.Sizeof(sharedMemHeader{}))
+ return m.region[valueOffset : valueOffset+length]
+}
+
+// valueCopy returns a copy of the value stored in shared memory.
+func (m *sharedMem) valueCopy() []byte {
+ ref := m.valueRef()
+ b := make([]byte, len(ref))
+ copy(b, ref)
+ return b
+}
+
+// setValue copies the data in b into the shared memory buffer and sets
+// the length. len(b) must be less than or equal to the capacity of the buffer
+// (as returned by cap(m.value())).
+func (m *sharedMem) setValue(b []byte) {
+ v := m.valueRef()
+ if len(b) > cap(v) {
+ panic(fmt.Sprintf("value length %d larger than shared memory capacity %d", len(b), cap(v)))
+ }
+ m.header().valueLen = len(b)
+ copy(v[:cap(v)], b)
+}
+
+// setValueLen sets the length of the shared memory buffer returned by valueRef
+// to n, which may be at most the cap of that slice.
+//
+// Note that we can only store the length in the shared memory header. The full
+// slice header contains a pointer, which is likely only valid for one process,
+// since each process can map shared memory at a different virtual address.
+func (m *sharedMem) setValueLen(n int) {
+ v := m.valueRef()
+ if n > cap(v) {
+ panic(fmt.Sprintf("length %d larger than shared memory capacity %d", n, cap(v)))
+ }
+ m.header().valueLen = n
+}
+
+// TODO(jayconrod): add method to resize the buffer. We'll need that when the
+// mutator can increase input length. Only the coordinator will be able to
+// do it, since we'll need to send a message to the worker telling it to
+// remap the file.
diff --git a/src/internal/fuzz/minimize.go b/src/internal/fuzz/minimize.go
new file mode 100644
index 0000000..974df36
--- /dev/null
+++ b/src/internal/fuzz/minimize.go
@@ -0,0 +1,116 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+import (
+ "math"
+ "reflect"
+)
+
+func isMinimizable(t reflect.Type) bool {
+ for _, v := range zeroVals {
+ if t == reflect.TypeOf(v) {
+ return true
+ }
+ }
+ return false
+}
+
+func minimizeBytes(v []byte, try func(interface{}) bool, shouldStop func() bool) {
+ tmp := make([]byte, len(v))
+ // If minimization was successful at any point during minimizeBytes,
+ // then the vals slice in (*workerServer).minimizeInput will point to
+ // tmp. Since tmp is altered while making new candidates, we need to
+ // make sure that it is equal to the correct value, v, before exiting
+ // this function.
+ defer copy(tmp, v)
+
+ // First, try to cut the tail.
+ for n := 1024; n != 0; n /= 2 {
+ for len(v) > n {
+ if shouldStop() {
+ return
+ }
+ candidate := v[:len(v)-n]
+ if !try(candidate) {
+ break
+ }
+ // Set v to the new value to continue iterating.
+ v = candidate
+ }
+ }
+
+ // Then, try to remove each individual byte.
+ for i := 0; i < len(v)-1; i++ {
+ if shouldStop() {
+ return
+ }
+ candidate := tmp[:len(v)-1]
+ copy(candidate[:i], v[:i])
+ copy(candidate[i:], v[i+1:])
+ if !try(candidate) {
+ continue
+ }
+ // Update v to delete the value at index i.
+ copy(v[i:], v[i+1:])
+ v = v[:len(candidate)]
+ // v[i] is now different, so decrement i to redo this iteration
+ // of the loop with the new value.
+ i--
+ }
+
+ // Then, try to remove each possible subset of bytes.
+ for i := 0; i < len(v)-1; i++ {
+ copy(tmp, v[:i])
+ for j := len(v); j > i+1; j-- {
+ if shouldStop() {
+ return
+ }
+ candidate := tmp[:len(v)-j+i]
+ copy(candidate[i:], v[j:])
+ if !try(candidate) {
+ continue
+ }
+ // Update v and reset the loop with the new length.
+ copy(v[i:], v[j:])
+ v = v[:len(candidate)]
+ j = len(v)
+ }
+ }
+}
+
+func minimizeInteger(v uint, try func(interface{}) bool, shouldStop func() bool) {
+ // TODO(rolandshoemaker): another approach could be either unsetting/setting all bits
+ // (depending on signed-ness), or rotating bits? When operating on cast signed integers
+ // this would probably be more complex though.
+ for ; v != 0; v /= 10 {
+ if shouldStop() {
+ return
+ }
+ // We ignore the return value here because there is no point
+ // advancing the loop, since there is nothing after this check,
+ // and we don't return early because a smaller value could
+ // re-trigger the crash.
+ try(v)
+ }
+}
+
+func minimizeFloat(v float64, try func(interface{}) bool, shouldStop func() bool) {
+ if math.IsNaN(v) {
+ return
+ }
+ minimized := float64(0)
+ for div := 10.0; minimized < v; div *= 10 {
+ if shouldStop() {
+ return
+ }
+ minimized = float64(int(v*div)) / div
+ if !try(minimized) {
+ // Since we are searching from least precision -> highest precision we
+ // can return early since we've already found the smallest value
+ return
+ }
+ }
+}
diff --git a/src/internal/fuzz/minimize_test.go b/src/internal/fuzz/minimize_test.go
new file mode 100644
index 0000000..410b783
--- /dev/null
+++ b/src/internal/fuzz/minimize_test.go
@@ -0,0 +1,286 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build darwin || linux || windows
+// +build darwin linux windows
+
+package fuzz
+
+import (
+ "bytes"
+ "context"
+ "errors"
+ "fmt"
+ "reflect"
+ "testing"
+)
+
+func TestMinimizeInput(t *testing.T) {
+ type testcase struct {
+ name string
+ fn func(CorpusEntry) error
+ input []interface{}
+ expected []interface{}
+ }
+ cases := []testcase{
+ {
+ name: "ones_byte",
+ fn: func(e CorpusEntry) error {
+ b := e.Values[0].([]byte)
+ ones := 0
+ for _, v := range b {
+ if v == 1 {
+ ones++
+ }
+ }
+ if ones == 3 {
+ return fmt.Errorf("bad %v", e.Values[0])
+ }
+ return nil
+ },
+ input: []interface{}{[]byte{0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+ expected: []interface{}{[]byte{1, 1, 1}},
+ },
+ {
+ name: "single_bytes",
+ fn: func(e CorpusEntry) error {
+ b := e.Values[0].([]byte)
+ if len(b) < 2 {
+ return nil
+ }
+ if len(b) == 2 && b[0] == 1 && b[1] == 2 {
+ return nil
+ }
+ return fmt.Errorf("bad %v", e.Values[0])
+ },
+ input: []interface{}{[]byte{1, 2, 3, 4, 5}},
+ expected: []interface{}{[]byte{2, 3}},
+ },
+ {
+ name: "set_of_bytes",
+ fn: func(e CorpusEntry) error {
+ b := e.Values[0].([]byte)
+ if len(b) < 3 {
+ return nil
+ }
+ if bytes.Equal(b, []byte{0, 1, 2, 3, 4, 5}) || bytes.Equal(b, []byte{0, 4, 5}) {
+ return fmt.Errorf("bad %v", e.Values[0])
+ }
+ return nil
+ },
+ input: []interface{}{[]byte{0, 1, 2, 3, 4, 5}},
+ expected: []interface{}{[]byte{0, 4, 5}},
+ },
+ {
+ name: "ones_string",
+ fn: func(e CorpusEntry) error {
+ b := e.Values[0].(string)
+ ones := 0
+ for _, v := range b {
+ if v == '1' {
+ ones++
+ }
+ }
+ if ones == 3 {
+ return fmt.Errorf("bad %v", e.Values[0])
+ }
+ return nil
+ },
+ input: []interface{}{"001010001000000000000000000"},
+ expected: []interface{}{"111"},
+ },
+ {
+ name: "int",
+ fn: func(e CorpusEntry) error {
+ i := e.Values[0].(int)
+ if i > 100 {
+ return fmt.Errorf("bad %v", e.Values[0])
+ }
+ return nil
+ },
+ input: []interface{}{123456},
+ expected: []interface{}{123},
+ },
+ {
+ name: "int8",
+ fn: func(e CorpusEntry) error {
+ i := e.Values[0].(int8)
+ if i > 10 {
+ return fmt.Errorf("bad %v", e.Values[0])
+ }
+ return nil
+ },
+ input: []interface{}{int8(1<<7 - 1)},
+ expected: []interface{}{int8(12)},
+ },
+ {
+ name: "int16",
+ fn: func(e CorpusEntry) error {
+ i := e.Values[0].(int16)
+ if i > 10 {
+ return fmt.Errorf("bad %v", e.Values[0])
+ }
+ return nil
+ },
+ input: []interface{}{int16(1<<15 - 1)},
+ expected: []interface{}{int16(32)},
+ },
+ {
+ fn: func(e CorpusEntry) error {
+ i := e.Values[0].(int32)
+ if i > 10 {
+ return fmt.Errorf("bad %v", e.Values[0])
+ }
+ return nil
+ },
+ input: []interface{}{int32(1<<31 - 1)},
+ expected: []interface{}{int32(21)},
+ },
+ {
+ name: "int32",
+ fn: func(e CorpusEntry) error {
+ i := e.Values[0].(uint)
+ if i > 10 {
+ return fmt.Errorf("bad %v", e.Values[0])
+ }
+ return nil
+ },
+ input: []interface{}{uint(123456)},
+ expected: []interface{}{uint(12)},
+ },
+ {
+ name: "uint8",
+ fn: func(e CorpusEntry) error {
+ i := e.Values[0].(uint8)
+ if i > 10 {
+ return fmt.Errorf("bad %v", e.Values[0])
+ }
+ return nil
+ },
+ input: []interface{}{uint8(1<<8 - 1)},
+ expected: []interface{}{uint8(25)},
+ },
+ {
+ name: "uint16",
+ fn: func(e CorpusEntry) error {
+ i := e.Values[0].(uint16)
+ if i > 10 {
+ return fmt.Errorf("bad %v", e.Values[0])
+ }
+ return nil
+ },
+ input: []interface{}{uint16(1<<16 - 1)},
+ expected: []interface{}{uint16(65)},
+ },
+ {
+ name: "uint32",
+ fn: func(e CorpusEntry) error {
+ i := e.Values[0].(uint32)
+ if i > 10 {
+ return fmt.Errorf("bad %v", e.Values[0])
+ }
+ return nil
+ },
+ input: []interface{}{uint32(1<<32 - 1)},
+ expected: []interface{}{uint32(42)},
+ },
+ {
+ name: "float32",
+ fn: func(e CorpusEntry) error {
+ if i := e.Values[0].(float32); i == 1.23 {
+ return nil
+ }
+ return fmt.Errorf("bad %v", e.Values[0])
+ },
+ input: []interface{}{float32(1.23456789)},
+ expected: []interface{}{float32(1.2)},
+ },
+ {
+ name: "float64",
+ fn: func(e CorpusEntry) error {
+ if i := e.Values[0].(float64); i == 1.23 {
+ return nil
+ }
+ return fmt.Errorf("bad %v", e.Values[0])
+ },
+ input: []interface{}{float64(1.23456789)},
+ expected: []interface{}{float64(1.2)},
+ },
+ }
+
+ // If we are on a 64 bit platform add int64 and uint64 tests
+ if v := int64(1<<63 - 1); int64(int(v)) == v {
+ cases = append(cases, testcase{
+ name: "int64",
+ fn: func(e CorpusEntry) error {
+ i := e.Values[0].(int64)
+ if i > 10 {
+ return fmt.Errorf("bad %v", e.Values[0])
+ }
+ return nil
+ },
+ input: []interface{}{int64(1<<63 - 1)},
+ expected: []interface{}{int64(92)},
+ }, testcase{
+ name: "uint64",
+ fn: func(e CorpusEntry) error {
+ i := e.Values[0].(uint64)
+ if i > 10 {
+ return fmt.Errorf("bad %v", e.Values[0])
+ }
+ return nil
+ },
+ input: []interface{}{uint64(1<<64 - 1)},
+ expected: []interface{}{uint64(18)},
+ })
+ }
+
+ for _, tc := range cases {
+ tc := tc
+ t.Run(tc.name, func(t *testing.T) {
+ t.Parallel()
+ ws := &workerServer{
+ fuzzFn: tc.fn,
+ }
+ count := int64(0)
+ vals := tc.input
+ success, err := ws.minimizeInput(context.Background(), vals, &count, 0, nil)
+ if !success {
+ t.Errorf("minimizeInput did not succeed")
+ }
+ if err == nil {
+ t.Fatal("minimizeInput didn't provide an error")
+ }
+ if expected := fmt.Sprintf("bad %v", tc.expected[0]); err.Error() != expected {
+ t.Errorf("unexpected error: got %q, want %q", err, expected)
+ }
+ if !reflect.DeepEqual(vals, tc.expected) {
+ t.Errorf("unexpected results: got %v, want %v", vals, tc.expected)
+ }
+ })
+ }
+}
+
+// TestMinimizeInputCoverageError checks that if we're minimizing an interesting
+// input (one that we don't expect to cause an error), and the fuzz function
+// returns an error, minimizing fails, and we return the error quickly.
+func TestMinimizeInputCoverageError(t *testing.T) {
+ errOhNo := errors.New("ohno")
+ ws := &workerServer{fuzzFn: func(e CorpusEntry) error {
+ return errOhNo
+ }}
+ keepCoverage := make([]byte, len(coverageSnapshot))
+ count := int64(0)
+ vals := []interface{}{[]byte(nil)}
+ success, err := ws.minimizeInput(context.Background(), vals, &count, 0, keepCoverage)
+ if success {
+ t.Error("unexpected success")
+ }
+ if err != errOhNo {
+ t.Errorf("unexpected error: %v", err)
+ }
+ if count != 1 {
+ t.Errorf("count: got %d, want 1", count)
+ }
+}
diff --git a/src/internal/fuzz/mutator.go b/src/internal/fuzz/mutator.go
new file mode 100644
index 0000000..9aa5678
--- /dev/null
+++ b/src/internal/fuzz/mutator.go
@@ -0,0 +1,317 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+import (
+ "encoding/binary"
+ "fmt"
+ "math"
+ "reflect"
+ "unsafe"
+)
+
+type mutator struct {
+ r mutatorRand
+ scratch []byte // scratch slice to avoid additional allocations
+}
+
+func newMutator() *mutator {
+ return &mutator{r: newPcgRand()}
+}
+
+func (m *mutator) rand(n int) int {
+ return m.r.intn(n)
+}
+
+func (m *mutator) randByteOrder() binary.ByteOrder {
+ if m.r.bool() {
+ return binary.LittleEndian
+ }
+ return binary.BigEndian
+}
+
+// chooseLen chooses length of range mutation in range [1,n]. It gives
+// preference to shorter ranges.
+func (m *mutator) chooseLen(n int) int {
+ switch x := m.rand(100); {
+ case x < 90:
+ return m.rand(min(8, n)) + 1
+ case x < 99:
+ return m.rand(min(32, n)) + 1
+ default:
+ return m.rand(n) + 1
+ }
+}
+
+func min(a, b int) int {
+ if a < b {
+ return a
+ }
+ return b
+}
+
+// mutate performs several mutations on the provided values.
+func (m *mutator) mutate(vals []interface{}, maxBytes int) {
+ // TODO(katiehockman): pull some of these functions into helper methods and
+ // test that each case is working as expected.
+ // TODO(katiehockman): perform more types of mutations for []byte.
+
+ // maxPerVal will represent the maximum number of bytes that each value be
+ // allowed after mutating, giving an equal amount of capacity to each line.
+ // Allow a little wiggle room for the encoding.
+ maxPerVal := maxBytes/len(vals) - 100
+
+ // Pick a random value to mutate.
+ // TODO: consider mutating more than one value at a time.
+ i := m.rand(len(vals))
+ switch v := vals[i].(type) {
+ case int:
+ vals[i] = int(m.mutateInt(int64(v), maxInt))
+ case int8:
+ vals[i] = int8(m.mutateInt(int64(v), math.MaxInt8))
+ case int16:
+ vals[i] = int16(m.mutateInt(int64(v), math.MaxInt16))
+ case int64:
+ vals[i] = m.mutateInt(v, maxInt)
+ case uint:
+ vals[i] = uint(m.mutateUInt(uint64(v), maxUint))
+ case uint16:
+ vals[i] = uint16(m.mutateUInt(uint64(v), math.MaxUint16))
+ case uint32:
+ vals[i] = uint32(m.mutateUInt(uint64(v), math.MaxUint32))
+ case uint64:
+ vals[i] = m.mutateUInt(uint64(v), maxUint)
+ case float32:
+ vals[i] = float32(m.mutateFloat(float64(v), math.MaxFloat32))
+ case float64:
+ vals[i] = m.mutateFloat(v, math.MaxFloat64)
+ case bool:
+ if m.rand(2) == 1 {
+ vals[i] = !v // 50% chance of flipping the bool
+ }
+ case rune: // int32
+ vals[i] = rune(m.mutateInt(int64(v), math.MaxInt32))
+ case byte: // uint8
+ vals[i] = byte(m.mutateUInt(uint64(v), math.MaxUint8))
+ case string:
+ if len(v) > maxPerVal {
+ panic(fmt.Sprintf("cannot mutate bytes of length %d", len(v)))
+ }
+ if cap(m.scratch) < maxPerVal {
+ m.scratch = append(make([]byte, 0, maxPerVal), v...)
+ } else {
+ m.scratch = m.scratch[:len(v)]
+ copy(m.scratch, v)
+ }
+ m.mutateBytes(&m.scratch)
+ var s string
+ shdr := (*reflect.StringHeader)(unsafe.Pointer(&s))
+ bhdr := (*reflect.SliceHeader)(unsafe.Pointer(&m.scratch))
+ shdr.Data = bhdr.Data
+ shdr.Len = bhdr.Len
+ vals[i] = s
+ case []byte:
+ if len(v) > maxPerVal {
+ panic(fmt.Sprintf("cannot mutate bytes of length %d", len(v)))
+ }
+ if cap(m.scratch) < maxPerVal {
+ m.scratch = append(make([]byte, 0, maxPerVal), v...)
+ } else {
+ m.scratch = m.scratch[:len(v)]
+ copy(m.scratch, v)
+ }
+ m.mutateBytes(&m.scratch)
+ vals[i] = m.scratch
+ default:
+ panic(fmt.Sprintf("type not supported for mutating: %T", vals[i]))
+ }
+}
+
+func (m *mutator) mutateInt(v, maxValue int64) int64 {
+ numIters := 1 + m.r.exp2()
+ var max int64
+ for iter := 0; iter < numIters; iter++ {
+ max = 100
+ switch m.rand(2) {
+ case 0:
+ // Add a random number
+ if v >= maxValue {
+ iter--
+ continue
+ }
+ if v > 0 && maxValue-v < max {
+ // Don't let v exceed maxValue
+ max = maxValue - v
+ }
+ v += int64(1 + m.rand(int(max)))
+ case 1:
+ // Subtract a random number
+ if v <= -maxValue {
+ iter--
+ continue
+ }
+ if v < 0 && maxValue+v < max {
+ // Don't let v drop below -maxValue
+ max = maxValue + v
+ }
+ v -= int64(1 + m.rand(int(max)))
+ }
+ }
+ return v
+}
+
+func (m *mutator) mutateUInt(v, maxValue uint64) uint64 {
+ numIters := 1 + m.r.exp2()
+ var max uint64
+ for iter := 0; iter < numIters; iter++ {
+ max = 100
+ switch m.rand(2) {
+ case 0:
+ // Add a random number
+ if v >= maxValue {
+ iter--
+ continue
+ }
+ if v > 0 && maxValue-v < max {
+ // Don't let v exceed maxValue
+ max = maxValue - v
+ }
+
+ v += uint64(1 + m.rand(int(max)))
+ case 1:
+ // Subtract a random number
+ if v <= 0 {
+ iter--
+ continue
+ }
+ if v < max {
+ // Don't let v drop below 0
+ max = v
+ }
+ v -= uint64(1 + m.rand(int(max)))
+ }
+ }
+ return v
+}
+
+func (m *mutator) mutateFloat(v, maxValue float64) float64 {
+ numIters := 1 + m.r.exp2()
+ var max float64
+ for iter := 0; iter < numIters; iter++ {
+ switch m.rand(4) {
+ case 0:
+ // Add a random number
+ if v >= maxValue {
+ iter--
+ continue
+ }
+ max = 100
+ if v > 0 && maxValue-v < max {
+ // Don't let v exceed maxValue
+ max = maxValue - v
+ }
+ v += float64(1 + m.rand(int(max)))
+ case 1:
+ // Subtract a random number
+ if v <= -maxValue {
+ iter--
+ continue
+ }
+ max = 100
+ if v < 0 && maxValue+v < max {
+ // Don't let v drop below -maxValue
+ max = maxValue + v
+ }
+ v -= float64(1 + m.rand(int(max)))
+ case 2:
+ // Multiply by a random number
+ absV := math.Abs(v)
+ if v == 0 || absV >= maxValue {
+ iter--
+ continue
+ }
+ max = 10
+ if maxValue/absV < max {
+ // Don't let v go beyond the minimum or maximum value
+ max = maxValue / absV
+ }
+ v *= float64(1 + m.rand(int(max)))
+ case 3:
+ // Divide by a random number
+ if v == 0 {
+ iter--
+ continue
+ }
+ v /= float64(1 + m.rand(10))
+ }
+ }
+ return v
+}
+
+type byteSliceMutator func(*mutator, []byte) []byte
+
+var byteSliceMutators = []byteSliceMutator{
+ byteSliceRemoveBytes,
+ byteSliceInsertRandomBytes,
+ byteSliceDuplicateBytes,
+ byteSliceOverwriteBytes,
+ byteSliceBitFlip,
+ byteSliceXORByte,
+ byteSliceSwapByte,
+ byteSliceArithmeticUint8,
+ byteSliceArithmeticUint16,
+ byteSliceArithmeticUint32,
+ byteSliceArithmeticUint64,
+ byteSliceOverwriteInterestingUint8,
+ byteSliceOverwriteInterestingUint16,
+ byteSliceOverwriteInterestingUint32,
+ byteSliceInsertConstantBytes,
+ byteSliceOverwriteConstantBytes,
+ byteSliceShuffleBytes,
+ byteSliceSwapBytes,
+}
+
+func (m *mutator) mutateBytes(ptrB *[]byte) {
+ b := *ptrB
+ defer func() {
+ oldHdr := (*reflect.SliceHeader)(unsafe.Pointer(ptrB))
+ newHdr := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+ if oldHdr.Data != newHdr.Data {
+ panic("data moved to new address")
+ }
+ *ptrB = b
+ }()
+
+ numIters := 1 + m.r.exp2()
+ for iter := 0; iter < numIters; iter++ {
+ mut := byteSliceMutators[m.rand(len(byteSliceMutators))]
+ mutated := mut(m, b)
+ if mutated == nil {
+ iter--
+ continue
+ }
+ b = mutated
+ }
+}
+
+var (
+ interesting8 = []int8{-128, -1, 0, 1, 16, 32, 64, 100, 127}
+ interesting16 = []int16{-32768, -129, 128, 255, 256, 512, 1000, 1024, 4096, 32767}
+ interesting32 = []int32{-2147483648, -100663046, -32769, 32768, 65535, 65536, 100663045, 2147483647}
+)
+
+const (
+ maxUint = uint64(^uint(0))
+ maxInt = int64(maxUint >> 1)
+)
+
+func init() {
+ for _, v := range interesting8 {
+ interesting16 = append(interesting16, int16(v))
+ }
+ for _, v := range interesting16 {
+ interesting32 = append(interesting32, int32(v))
+ }
+}
diff --git a/src/internal/fuzz/mutator_test.go b/src/internal/fuzz/mutator_test.go
new file mode 100644
index 0000000..ee2912d
--- /dev/null
+++ b/src/internal/fuzz/mutator_test.go
@@ -0,0 +1,101 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+import (
+ "fmt"
+ "os"
+ "strconv"
+ "testing"
+)
+
+func BenchmarkMutatorBytes(b *testing.B) {
+ origEnv := os.Getenv("GODEBUG")
+ defer func() { os.Setenv("GODEBUG", origEnv) }()
+ os.Setenv("GODEBUG", fmt.Sprintf("%s,fuzzseed=123", origEnv))
+ m := newMutator()
+
+ for _, size := range []int{
+ 1,
+ 10,
+ 100,
+ 1000,
+ 10000,
+ 100000,
+ } {
+ b.Run(strconv.Itoa(size), func(b *testing.B) {
+ buf := make([]byte, size)
+ b.ResetTimer()
+
+ for i := 0; i < b.N; i++ {
+ // resize buffer to the correct shape and reset the PCG
+ buf = buf[0:size]
+ m.r = newPcgRand()
+ m.mutate([]interface{}{buf}, workerSharedMemSize)
+ }
+ })
+ }
+}
+
+func BenchmarkMutatorString(b *testing.B) {
+ origEnv := os.Getenv("GODEBUG")
+ defer func() { os.Setenv("GODEBUG", origEnv) }()
+ os.Setenv("GODEBUG", fmt.Sprintf("%s,fuzzseed=123", origEnv))
+ m := newMutator()
+
+ for _, size := range []int{
+ 1,
+ 10,
+ 100,
+ 1000,
+ 10000,
+ 100000,
+ } {
+ b.Run(strconv.Itoa(size), func(b *testing.B) {
+ buf := make([]byte, size)
+ b.ResetTimer()
+
+ for i := 0; i < b.N; i++ {
+ // resize buffer to the correct shape and reset the PCG
+ buf = buf[0:size]
+ m.r = newPcgRand()
+ m.mutate([]interface{}{string(buf)}, workerSharedMemSize)
+ }
+ })
+ }
+}
+
+func BenchmarkMutatorAllBasicTypes(b *testing.B) {
+ origEnv := os.Getenv("GODEBUG")
+ defer func() { os.Setenv("GODEBUG", origEnv) }()
+ os.Setenv("GODEBUG", fmt.Sprintf("%s,fuzzseed=123", origEnv))
+ m := newMutator()
+
+ types := []interface{}{
+ []byte(""),
+ string(""),
+ false,
+ float32(0),
+ float64(0),
+ int(0),
+ int8(0),
+ int16(0),
+ int32(0),
+ int64(0),
+ uint8(0),
+ uint16(0),
+ uint32(0),
+ uint64(0),
+ }
+
+ for _, t := range types {
+ b.Run(fmt.Sprintf("%T", t), func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ m.r = newPcgRand()
+ m.mutate([]interface{}{t}, workerSharedMemSize)
+ }
+ })
+ }
+}
diff --git a/src/internal/fuzz/mutators_byteslice.go b/src/internal/fuzz/mutators_byteslice.go
new file mode 100644
index 0000000..7c96b59
--- /dev/null
+++ b/src/internal/fuzz/mutators_byteslice.go
@@ -0,0 +1,301 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+// byteSliceRemoveBytes removes a random chunk of bytes from b.
+func byteSliceRemoveBytes(m *mutator, b []byte) []byte {
+ if len(b) <= 1 {
+ return nil
+ }
+ pos0 := m.rand(len(b))
+ pos1 := pos0 + m.chooseLen(len(b)-pos0)
+ copy(b[pos0:], b[pos1:])
+ b = b[:len(b)-(pos1-pos0)]
+ return b
+}
+
+// byteSliceInsertRandomBytes inserts a chunk of random bytes into b at a random
+// position.
+func byteSliceInsertRandomBytes(m *mutator, b []byte) []byte {
+ pos := m.rand(len(b) + 1)
+ n := m.chooseLen(1024)
+ if len(b)+n >= cap(b) {
+ return nil
+ }
+ b = b[:len(b)+n]
+ copy(b[pos+n:], b[pos:])
+ for i := 0; i < n; i++ {
+ b[pos+i] = byte(m.rand(256))
+ }
+ return b
+}
+
+// byteSliceDuplicateBytes duplicates a chunk of bytes in b and inserts it into
+// a random position.
+func byteSliceDuplicateBytes(m *mutator, b []byte) []byte {
+ if len(b) <= 1 {
+ return nil
+ }
+ src := m.rand(len(b))
+ dst := m.rand(len(b))
+ for dst == src {
+ dst = m.rand(len(b))
+ }
+ n := m.chooseLen(len(b) - src)
+ // Use the end of the slice as scratch space to avoid doing an
+ // allocation. If the slice is too small abort and try something
+ // else.
+ if len(b)+(n*2) >= cap(b) {
+ return nil
+ }
+ end := len(b)
+ // Increase the size of b to fit the duplicated block as well as
+ // some extra working space
+ b = b[:end+(n*2)]
+ // Copy the block of bytes we want to duplicate to the end of the
+ // slice
+ copy(b[end+n:], b[src:src+n])
+ // Shift the bytes after the splice point n positions to the right
+ // to make room for the new block
+ copy(b[dst+n:end+n], b[dst:end])
+ // Insert the duplicate block into the splice point
+ copy(b[dst:], b[end+n:])
+ b = b[:end+n]
+ return b
+}
+
+// byteSliceOverwriteBytes overwrites a chunk of b with another chunk of b.
+func byteSliceOverwriteBytes(m *mutator, b []byte) []byte {
+ if len(b) <= 1 {
+ return nil
+ }
+ src := m.rand(len(b))
+ dst := m.rand(len(b))
+ for dst == src {
+ dst = m.rand(len(b))
+ }
+ n := m.chooseLen(len(b) - src - 1)
+ copy(b[dst:], b[src:src+n])
+ return b
+}
+
+// byteSliceBitFlip flips a random bit in a random byte in b.
+func byteSliceBitFlip(m *mutator, b []byte) []byte {
+ if len(b) == 0 {
+ return nil
+ }
+ pos := m.rand(len(b))
+ b[pos] ^= 1 << uint(m.rand(8))
+ return b
+}
+
+// byteSliceXORByte XORs a random byte in b with a random value.
+func byteSliceXORByte(m *mutator, b []byte) []byte {
+ if len(b) == 0 {
+ return nil
+ }
+ pos := m.rand(len(b))
+ // In order to avoid a no-op (where the random value matches
+ // the existing value), use XOR instead of just setting to
+ // the random value.
+ b[pos] ^= byte(1 + m.rand(255))
+ return b
+}
+
+// byteSliceSwapByte swaps two random bytes in b.
+func byteSliceSwapByte(m *mutator, b []byte) []byte {
+ if len(b) <= 1 {
+ return nil
+ }
+ src := m.rand(len(b))
+ dst := m.rand(len(b))
+ for dst == src {
+ dst = m.rand(len(b))
+ }
+ b[src], b[dst] = b[dst], b[src]
+ return b
+}
+
+// byteSliceArithmeticUint8 adds/subtracts from a random byte in b.
+func byteSliceArithmeticUint8(m *mutator, b []byte) []byte {
+ if len(b) == 0 {
+ return nil
+ }
+ pos := m.rand(len(b))
+ v := byte(m.rand(35) + 1)
+ if m.r.bool() {
+ b[pos] += v
+ } else {
+ b[pos] -= v
+ }
+ return b
+}
+
+// byteSliceArithmeticUint16 adds/subtracts from a random uint16 in b.
+func byteSliceArithmeticUint16(m *mutator, b []byte) []byte {
+ if len(b) < 2 {
+ return nil
+ }
+ v := uint16(m.rand(35) + 1)
+ if m.r.bool() {
+ v = 0 - v
+ }
+ pos := m.rand(len(b) - 1)
+ enc := m.randByteOrder()
+ enc.PutUint16(b[pos:], enc.Uint16(b[pos:])+v)
+ return b
+}
+
+// byteSliceArithmeticUint32 adds/subtracts from a random uint32 in b.
+func byteSliceArithmeticUint32(m *mutator, b []byte) []byte {
+ if len(b) < 4 {
+ return nil
+ }
+ v := uint32(m.rand(35) + 1)
+ if m.r.bool() {
+ v = 0 - v
+ }
+ pos := m.rand(len(b) - 3)
+ enc := m.randByteOrder()
+ enc.PutUint32(b[pos:], enc.Uint32(b[pos:])+v)
+ return b
+}
+
+// byteSliceArithmeticUint64 adds/subtracts from a random uint64 in b.
+func byteSliceArithmeticUint64(m *mutator, b []byte) []byte {
+ if len(b) < 8 {
+ return nil
+ }
+ v := uint64(m.rand(35) + 1)
+ if m.r.bool() {
+ v = 0 - v
+ }
+ pos := m.rand(len(b) - 7)
+ enc := m.randByteOrder()
+ enc.PutUint64(b[pos:], enc.Uint64(b[pos:])+v)
+ return b
+}
+
+// byteSliceOverwriteInterestingUint8 overwrites a random byte in b with an interesting
+// value.
+func byteSliceOverwriteInterestingUint8(m *mutator, b []byte) []byte {
+ if len(b) == 0 {
+ return nil
+ }
+ pos := m.rand(len(b))
+ b[pos] = byte(interesting8[m.rand(len(interesting8))])
+ return b
+}
+
+// byteSliceOverwriteInterestingUint16 overwrites a random uint16 in b with an interesting
+// value.
+func byteSliceOverwriteInterestingUint16(m *mutator, b []byte) []byte {
+ if len(b) < 2 {
+ return nil
+ }
+ pos := m.rand(len(b) - 1)
+ v := uint16(interesting16[m.rand(len(interesting16))])
+ m.randByteOrder().PutUint16(b[pos:], v)
+ return b
+}
+
+// byteSliceOverwriteInterestingUint32 overwrites a random uint16 in b with an interesting
+// value.
+func byteSliceOverwriteInterestingUint32(m *mutator, b []byte) []byte {
+ if len(b) < 4 {
+ return nil
+ }
+ pos := m.rand(len(b) - 3)
+ v := uint32(interesting32[m.rand(len(interesting32))])
+ m.randByteOrder().PutUint32(b[pos:], v)
+ return b
+}
+
+// byteSliceInsertConstantBytes inserts a chunk of constant bytes into a random position in b.
+func byteSliceInsertConstantBytes(m *mutator, b []byte) []byte {
+ if len(b) <= 1 {
+ return nil
+ }
+ dst := m.rand(len(b))
+ // TODO(rolandshoemaker,katiehockman): 4096 was mainly picked
+ // randomly. We may want to either pick a much larger value
+ // (AFL uses 32768, paired with a similar impl to chooseLen
+ // which biases towards smaller lengths that grow over time),
+ // or set the max based on characteristics of the corpus
+ // (libFuzzer sets a min/max based on the min/max size of
+ // entries in the corpus and then picks uniformly from
+ // that range).
+ n := m.chooseLen(4096)
+ if len(b)+n >= cap(b) {
+ return nil
+ }
+ b = b[:len(b)+n]
+ copy(b[dst+n:], b[dst:])
+ rb := byte(m.rand(256))
+ for i := dst; i < dst+n; i++ {
+ b[i] = rb
+ }
+ return b
+}
+
+// byteSliceOverwriteConstantBytes overwrites a chunk of b with constant bytes.
+func byteSliceOverwriteConstantBytes(m *mutator, b []byte) []byte {
+ if len(b) <= 1 {
+ return nil
+ }
+ dst := m.rand(len(b))
+ n := m.chooseLen(len(b) - dst)
+ rb := byte(m.rand(256))
+ for i := dst; i < dst+n; i++ {
+ b[i] = rb
+ }
+ return b
+}
+
+// byteSliceShuffleBytes shuffles a chunk of bytes in b.
+func byteSliceShuffleBytes(m *mutator, b []byte) []byte {
+ if len(b) <= 1 {
+ return nil
+ }
+ dst := m.rand(len(b))
+ n := m.chooseLen(len(b) - dst)
+ if n <= 2 {
+ return nil
+ }
+ // Start at the end of the range, and iterate backwards
+ // to dst, swapping each element with another element in
+ // dst:dst+n (Fisher-Yates shuffle).
+ for i := n - 1; i > 0; i-- {
+ j := m.rand(i + 1)
+ b[dst+i], b[dst+j] = b[dst+j], b[dst+i]
+ }
+ return b
+}
+
+// byteSliceSwapBytes swaps two chunks of bytes in b.
+func byteSliceSwapBytes(m *mutator, b []byte) []byte {
+ if len(b) <= 1 {
+ return nil
+ }
+ src := m.rand(len(b))
+ dst := m.rand(len(b))
+ for dst == src {
+ dst = m.rand(len(b))
+ }
+ n := m.chooseLen(len(b) - src - 1)
+ // Use the end of the slice as scratch space to avoid doing an
+ // allocation. If the slice is too small abort and try something
+ // else.
+ if len(b)+n >= cap(b) {
+ return nil
+ }
+ end := len(b)
+ b = b[:end+n]
+ copy(b[end:], b[dst:dst+n])
+ copy(b[dst:], b[src:src+n])
+ copy(b[src:], b[end:])
+ b = b[:end]
+ return b
+}
diff --git a/src/internal/fuzz/mutators_byteslice_test.go b/src/internal/fuzz/mutators_byteslice_test.go
new file mode 100644
index 0000000..50a39a9
--- /dev/null
+++ b/src/internal/fuzz/mutators_byteslice_test.go
@@ -0,0 +1,179 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+import (
+ "bytes"
+ "testing"
+)
+
+type mockRand struct {
+ counter int
+ b bool
+}
+
+func (mr *mockRand) uint32() uint32 {
+ c := mr.counter
+ mr.counter++
+ return uint32(c)
+}
+
+func (mr *mockRand) intn(n int) int {
+ c := mr.counter
+ mr.counter++
+ return c % n
+}
+
+func (mr *mockRand) uint32n(n uint32) uint32 {
+ c := mr.counter
+ mr.counter++
+ return uint32(c) % n
+}
+
+func (mr *mockRand) exp2() int {
+ c := mr.counter
+ mr.counter++
+ return c
+}
+
+func (mr *mockRand) bool() bool {
+ b := mr.b
+ mr.b = !mr.b
+ return b
+}
+
+func (mr *mockRand) save(*uint64, *uint64) {
+ panic("unimplemented")
+}
+
+func (mr *mockRand) restore(uint64, uint64) {
+ panic("unimplemented")
+}
+
+func TestByteSliceMutators(t *testing.T) {
+ for _, tc := range []struct {
+ name string
+ mutator func(*mutator, []byte) []byte
+ input []byte
+ expected []byte
+ }{
+ {
+ name: "byteSliceRemoveBytes",
+ mutator: byteSliceRemoveBytes,
+ input: []byte{1, 2, 3, 4},
+ expected: []byte{4},
+ },
+ {
+ name: "byteSliceInsertRandomBytes",
+ mutator: byteSliceInsertRandomBytes,
+ input: make([]byte, 4, 8),
+ expected: []byte{3, 4, 5, 0, 0, 0, 0},
+ },
+ {
+ name: "byteSliceDuplicateBytes",
+ mutator: byteSliceDuplicateBytes,
+ input: append(make([]byte, 0, 13), []byte{1, 2, 3, 4}...),
+ expected: []byte{1, 1, 2, 3, 4, 2, 3, 4},
+ },
+ {
+ name: "byteSliceOverwriteBytes",
+ mutator: byteSliceOverwriteBytes,
+ input: []byte{1, 2, 3, 4},
+ expected: []byte{1, 1, 3, 4},
+ },
+ {
+ name: "byteSliceBitFlip",
+ mutator: byteSliceBitFlip,
+ input: []byte{1, 2, 3, 4},
+ expected: []byte{3, 2, 3, 4},
+ },
+ {
+ name: "byteSliceXORByte",
+ mutator: byteSliceXORByte,
+ input: []byte{1, 2, 3, 4},
+ expected: []byte{3, 2, 3, 4},
+ },
+ {
+ name: "byteSliceSwapByte",
+ mutator: byteSliceSwapByte,
+ input: []byte{1, 2, 3, 4},
+ expected: []byte{2, 1, 3, 4},
+ },
+ {
+ name: "byteSliceArithmeticUint8",
+ mutator: byteSliceArithmeticUint8,
+ input: []byte{1, 2, 3, 4},
+ expected: []byte{255, 2, 3, 4},
+ },
+ {
+ name: "byteSliceArithmeticUint16",
+ mutator: byteSliceArithmeticUint16,
+ input: []byte{1, 2, 3, 4},
+ expected: []byte{1, 3, 3, 4},
+ },
+ {
+ name: "byteSliceArithmeticUint32",
+ mutator: byteSliceArithmeticUint32,
+ input: []byte{1, 2, 3, 4},
+ expected: []byte{2, 2, 3, 4},
+ },
+ {
+ name: "byteSliceArithmeticUint64",
+ mutator: byteSliceArithmeticUint64,
+ input: []byte{1, 2, 3, 4, 5, 6, 7, 8},
+ expected: []byte{2, 2, 3, 4, 5, 6, 7, 8},
+ },
+ {
+ name: "byteSliceOverwriteInterestingUint8",
+ mutator: byteSliceOverwriteInterestingUint8,
+ input: []byte{1, 2, 3, 4},
+ expected: []byte{255, 2, 3, 4},
+ },
+ {
+ name: "byteSliceOverwriteInterestingUint16",
+ mutator: byteSliceOverwriteInterestingUint16,
+ input: []byte{1, 2, 3, 4},
+ expected: []byte{255, 127, 3, 4},
+ },
+ {
+ name: "byteSliceOverwriteInterestingUint32",
+ mutator: byteSliceOverwriteInterestingUint32,
+ input: []byte{1, 2, 3, 4},
+ expected: []byte{250, 0, 0, 250},
+ },
+ {
+ name: "byteSliceInsertConstantBytes",
+ mutator: byteSliceInsertConstantBytes,
+ input: append(make([]byte, 0, 8), []byte{1, 2, 3, 4}...),
+ expected: []byte{3, 3, 3, 1, 2, 3, 4},
+ },
+ {
+ name: "byteSliceOverwriteConstantBytes",
+ mutator: byteSliceOverwriteConstantBytes,
+ input: []byte{1, 2, 3, 4},
+ expected: []byte{3, 3, 3, 4},
+ },
+ {
+ name: "byteSliceShuffleBytes",
+ mutator: byteSliceShuffleBytes,
+ input: []byte{1, 2, 3, 4},
+ expected: []byte{2, 3, 1, 4},
+ },
+ {
+ name: "byteSliceSwapBytes",
+ mutator: byteSliceSwapBytes,
+ input: append(make([]byte, 0, 9), []byte{1, 2, 3, 4}...),
+ expected: []byte{2, 1, 3, 4},
+ },
+ } {
+ t.Run(tc.name, func(t *testing.T) {
+ m := &mutator{r: &mockRand{}}
+ b := tc.mutator(m, tc.input)
+ if !bytes.Equal(b, tc.expected) {
+ t.Errorf("got %x, want %x", b, tc.expected)
+ }
+ })
+ }
+}
diff --git a/src/internal/fuzz/pcg.go b/src/internal/fuzz/pcg.go
new file mode 100644
index 0000000..c9ea0af
--- /dev/null
+++ b/src/internal/fuzz/pcg.go
@@ -0,0 +1,145 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+import (
+ "math/bits"
+ "os"
+ "strconv"
+ "strings"
+ "sync/atomic"
+ "time"
+)
+
+type mutatorRand interface {
+ uint32() uint32
+ intn(int) int
+ uint32n(uint32) uint32
+ exp2() int
+ bool() bool
+
+ save(randState, randInc *uint64)
+ restore(randState, randInc uint64)
+}
+
+// The functions in pcg implement a 32 bit PRNG with a 64 bit period: pcg xsh rr
+// 64 32. See https://www.pcg-random.org/ for more information. This
+// implementation is geared specifically towards the needs of fuzzing: Simple
+// creation and use, no reproducibility, no concurrency safety, just the
+// necessary methods, optimized for speed.
+
+var globalInc uint64 // PCG stream
+
+const multiplier uint64 = 6364136223846793005
+
+// pcgRand is a PRNG. It should not be copied or shared. No Rand methods are
+// concurrency safe.
+type pcgRand struct {
+ noCopy noCopy // help avoid mistakes: ask vet to ensure that we don't make a copy
+ state uint64
+ inc uint64
+}
+
+func godebugSeed() *int {
+ debug := strings.Split(os.Getenv("GODEBUG"), ",")
+ for _, f := range debug {
+ if strings.HasPrefix(f, "fuzzseed=") {
+ seed, err := strconv.Atoi(strings.TrimPrefix(f, "fuzzseed="))
+ if err != nil {
+ panic("malformed fuzzseed")
+ }
+ return &seed
+ }
+ }
+ return nil
+}
+
+// newPcgRand generates a new, seeded Rand, ready for use.
+func newPcgRand() *pcgRand {
+ r := new(pcgRand)
+ now := uint64(time.Now().UnixNano())
+ if seed := godebugSeed(); seed != nil {
+ now = uint64(*seed)
+ }
+ inc := atomic.AddUint64(&globalInc, 1)
+ r.state = now
+ r.inc = (inc << 1) | 1
+ r.step()
+ r.state += now
+ r.step()
+ return r
+}
+
+func (r *pcgRand) step() {
+ r.state *= multiplier
+ r.state += r.inc
+}
+
+func (r *pcgRand) save(randState, randInc *uint64) {
+ *randState = r.state
+ *randInc = r.inc
+}
+
+func (r *pcgRand) restore(randState, randInc uint64) {
+ r.state = randState
+ r.inc = randInc
+}
+
+// uint32 returns a pseudo-random uint32.
+func (r *pcgRand) uint32() uint32 {
+ x := r.state
+ r.step()
+ return bits.RotateLeft32(uint32(((x>>18)^x)>>27), -int(x>>59))
+}
+
+// intn returns a pseudo-random number in [0, n).
+// n must fit in a uint32.
+func (r *pcgRand) intn(n int) int {
+ if int(uint32(n)) != n {
+ panic("large Intn")
+ }
+ return int(r.uint32n(uint32(n)))
+}
+
+// uint32n returns a pseudo-random number in [0, n).
+//
+// For implementation details, see:
+// https://lemire.me/blog/2016/06/27/a-fast-alternative-to-the-modulo-reduction
+// https://lemire.me/blog/2016/06/30/fast-random-shuffling
+func (r *pcgRand) uint32n(n uint32) uint32 {
+ v := r.uint32()
+ prod := uint64(v) * uint64(n)
+ low := uint32(prod)
+ if low < n {
+ thresh := uint32(-int32(n)) % n
+ for low < thresh {
+ v = r.uint32()
+ prod = uint64(v) * uint64(n)
+ low = uint32(prod)
+ }
+ }
+ return uint32(prod >> 32)
+}
+
+// exp2 generates n with probability 1/2^(n+1).
+func (r *pcgRand) exp2() int {
+ return bits.TrailingZeros32(r.uint32())
+}
+
+// bool generates a random bool.
+func (r *pcgRand) bool() bool {
+ return r.uint32()&1 == 0
+}
+
+// noCopy may be embedded into structs which must not be copied
+// after the first use.
+//
+// See https://golang.org/issues/8005#issuecomment-190753527
+// for details.
+type noCopy struct{}
+
+// lock is a no-op used by -copylocks checker from `go vet`.
+func (*noCopy) lock() {}
+func (*noCopy) unlock() {}
diff --git a/src/internal/fuzz/queue.go b/src/internal/fuzz/queue.go
new file mode 100644
index 0000000..cf67a28
--- /dev/null
+++ b/src/internal/fuzz/queue.go
@@ -0,0 +1,71 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+// queue holds a growable sequence of inputs for fuzzing and minimization.
+//
+// For now, this is a simple ring buffer
+// (https://en.wikipedia.org/wiki/Circular_buffer).
+//
+// TODO(golang.org/issue/46224): use a priotization algorithm based on input
+// size, previous duration, coverage, and any other metrics that seem useful.
+type queue struct {
+ // elems holds a ring buffer.
+ // The queue is empty when begin = end.
+ // The queue is full (until grow is called) when end = begin + N - 1 (mod N)
+ // where N = cap(elems).
+ elems []interface{}
+ head, len int
+}
+
+func (q *queue) cap() int {
+ return len(q.elems)
+}
+
+func (q *queue) grow() {
+ oldCap := q.cap()
+ newCap := oldCap * 2
+ if newCap == 0 {
+ newCap = 8
+ }
+ newElems := make([]interface{}, newCap)
+ oldLen := q.len
+ for i := 0; i < oldLen; i++ {
+ newElems[i] = q.elems[(q.head+i)%oldCap]
+ }
+ q.elems = newElems
+ q.head = 0
+}
+
+func (q *queue) enqueue(e interface{}) {
+ if q.len+1 > q.cap() {
+ q.grow()
+ }
+ i := (q.head + q.len) % q.cap()
+ q.elems[i] = e
+ q.len++
+}
+
+func (q *queue) dequeue() (interface{}, bool) {
+ if q.len == 0 {
+ return nil, false
+ }
+ e := q.elems[q.head]
+ q.elems[q.head] = nil
+ q.head = (q.head + 1) % q.cap()
+ q.len--
+ return e, true
+}
+
+func (q *queue) peek() (interface{}, bool) {
+ if q.len == 0 {
+ return nil, false
+ }
+ return q.elems[q.head], true
+}
+
+func (q *queue) clear() {
+ *q = queue{}
+}
diff --git a/src/internal/fuzz/queue_test.go b/src/internal/fuzz/queue_test.go
new file mode 100644
index 0000000..3b179af
--- /dev/null
+++ b/src/internal/fuzz/queue_test.go
@@ -0,0 +1,58 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+import "testing"
+
+func TestQueue(t *testing.T) {
+ // Zero valued queue should have 0 length and capacity.
+ var q queue
+ if n := q.len; n != 0 {
+ t.Fatalf("empty queue has len %d; want 0", n)
+ }
+ if n := q.cap(); n != 0 {
+ t.Fatalf("empty queue has cap %d; want 0", n)
+ }
+
+ // As we add elements, len should grow.
+ N := 32
+ for i := 0; i < N; i++ {
+ q.enqueue(i)
+ if n := q.len; n != i+1 {
+ t.Fatalf("after adding %d elements, queue has len %d", i, n)
+ }
+ if v, ok := q.peek(); !ok {
+ t.Fatalf("couldn't peek after adding %d elements", i)
+ } else if v.(int) != 0 {
+ t.Fatalf("after adding %d elements, peek is %d; want 0", i, v)
+ }
+ }
+
+ // As we remove and add elements, len should shrink and grow.
+ // We should also remove elements in the same order they were added.
+ want := 0
+ for _, r := range []int{1, 2, 3, 5, 8, 13, 21} {
+ s := make([]int, 0, r)
+ for i := 0; i < r; i++ {
+ if got, ok := q.dequeue(); !ok {
+ t.Fatalf("after removing %d of %d elements, could not dequeue", i+1, r)
+ } else if got != want {
+ t.Fatalf("after removing %d of %d elements, got %d; want %d", i+1, r, got, want)
+ } else {
+ s = append(s, got.(int))
+ }
+ want = (want + 1) % N
+ if n := q.len; n != N-i-1 {
+ t.Fatalf("after removing %d of %d elements, len is %d; want %d", i+1, r, n, N-i-1)
+ }
+ }
+ for i, v := range s {
+ q.enqueue(v)
+ if n := q.len; n != N-r+i+1 {
+ t.Fatalf("after adding back %d of %d elements, len is %d; want %d", i+1, r, n, n-r+i+1)
+ }
+ }
+ }
+}
diff --git a/src/internal/fuzz/sys_posix.go b/src/internal/fuzz/sys_posix.go
new file mode 100644
index 0000000..2473274
--- /dev/null
+++ b/src/internal/fuzz/sys_posix.go
@@ -0,0 +1,131 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build darwin || linux
+// +build darwin linux
+
+package fuzz
+
+import (
+ "fmt"
+ "os"
+ "os/exec"
+ "syscall"
+)
+
+type sharedMemSys struct{}
+
+func sharedMemMapFile(f *os.File, size int, removeOnClose bool) (*sharedMem, error) {
+ prot := syscall.PROT_READ | syscall.PROT_WRITE
+ flags := syscall.MAP_FILE | syscall.MAP_SHARED
+ region, err := syscall.Mmap(int(f.Fd()), 0, size, prot, flags)
+ if err != nil {
+ return nil, err
+ }
+
+ return &sharedMem{f: f, region: region, removeOnClose: removeOnClose}, nil
+}
+
+// Close unmaps the shared memory and closes the temporary file. If this
+// sharedMem was created with sharedMemTempFile, Close also removes the file.
+func (m *sharedMem) Close() error {
+ // Attempt all operations, even if we get an error for an earlier operation.
+ // os.File.Close may fail due to I/O errors, but we still want to delete
+ // the temporary file.
+ var errs []error
+ errs = append(errs,
+ syscall.Munmap(m.region),
+ m.f.Close())
+ if m.removeOnClose {
+ errs = append(errs, os.Remove(m.f.Name()))
+ }
+ for _, err := range errs {
+ if err != nil {
+ return err
+ }
+ }
+ return nil
+}
+
+// setWorkerComm configures communciation channels on the cmd that will
+// run a worker process.
+func setWorkerComm(cmd *exec.Cmd, comm workerComm) {
+ mem := <-comm.memMu
+ memFile := mem.f
+ comm.memMu <- mem
+ cmd.ExtraFiles = []*os.File{comm.fuzzIn, comm.fuzzOut, memFile}
+}
+
+// getWorkerComm returns communication channels in the worker process.
+func getWorkerComm() (comm workerComm, err error) {
+ fuzzIn := os.NewFile(3, "fuzz_in")
+ fuzzOut := os.NewFile(4, "fuzz_out")
+ memFile := os.NewFile(5, "fuzz_mem")
+ fi, err := memFile.Stat()
+ if err != nil {
+ return workerComm{}, err
+ }
+ size := int(fi.Size())
+ if int64(size) != fi.Size() {
+ return workerComm{}, fmt.Errorf("fuzz temp file exceeds maximum size")
+ }
+ removeOnClose := false
+ mem, err := sharedMemMapFile(memFile, size, removeOnClose)
+ if err != nil {
+ return workerComm{}, err
+ }
+ memMu := make(chan *sharedMem, 1)
+ memMu <- mem
+ return workerComm{fuzzIn: fuzzIn, fuzzOut: fuzzOut, memMu: memMu}, nil
+}
+
+// isInterruptError returns whether an error was returned by a process that
+// was terminated by an interrupt signal (SIGINT).
+func isInterruptError(err error) bool {
+ exitErr, ok := err.(*exec.ExitError)
+ if !ok || exitErr.ExitCode() >= 0 {
+ return false
+ }
+ status := exitErr.Sys().(syscall.WaitStatus)
+ return status.Signal() == syscall.SIGINT
+}
+
+// terminationSignal checks if err is an exec.ExitError with a signal status.
+// If it is, terminationSignal returns the signal and true.
+// If not, -1 and false.
+func terminationSignal(err error) (os.Signal, bool) {
+ exitErr, ok := err.(*exec.ExitError)
+ if !ok || exitErr.ExitCode() >= 0 {
+ return syscall.Signal(-1), false
+ }
+ status := exitErr.Sys().(syscall.WaitStatus)
+ return status.Signal(), status.Signaled()
+}
+
+// isCrashSignal returns whether a signal was likely to have been caused by an
+// error in the program that received it, triggered by a fuzz input. For
+// example, SIGSEGV would be received after a nil pointer dereference.
+// Other signals like SIGKILL or SIGHUP are more likely to have been sent by
+// another process, and we shouldn't record a crasher if the worker process
+// receives one of these.
+//
+// Note that Go installs its own signal handlers on startup, so some of these
+// signals may only be received if signal handlers are changed. For example,
+// SIGSEGV is normally transformed into a panic that causes the process to exit
+// with status 2 if not recovered, which we handle as a crash.
+func isCrashSignal(signal os.Signal) bool {
+ switch signal {
+ case
+ syscall.SIGILL, // illegal instruction
+ syscall.SIGTRAP, // breakpoint
+ syscall.SIGABRT, // abort() called
+ syscall.SIGBUS, // invalid memory access (e.g., misaligned address)
+ syscall.SIGFPE, // math error, e.g., integer divide by zero
+ syscall.SIGSEGV, // invalid memory access (e.g., write to read-only)
+ syscall.SIGPIPE: // sent data to closed pipe or socket
+ return true
+ default:
+ return false
+ }
+}
diff --git a/src/internal/fuzz/sys_unimplemented.go b/src/internal/fuzz/sys_unimplemented.go
new file mode 100644
index 0000000..827e36c
--- /dev/null
+++ b/src/internal/fuzz/sys_unimplemented.go
@@ -0,0 +1,44 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// TODO(jayconrod): support more platforms.
+//go:build !darwin && !linux && !windows
+// +build !darwin,!linux,!windows
+
+package fuzz
+
+import (
+ "os"
+ "os/exec"
+)
+
+type sharedMemSys struct{}
+
+func sharedMemMapFile(f *os.File, size int, removeOnClose bool) (*sharedMem, error) {
+ panic("not implemented")
+}
+
+func (m *sharedMem) Close() error {
+ panic("not implemented")
+}
+
+func setWorkerComm(cmd *exec.Cmd, comm workerComm) {
+ panic("not implemented")
+}
+
+func getWorkerComm() (comm workerComm, err error) {
+ panic("not implemented")
+}
+
+func isInterruptError(err error) bool {
+ panic("not implemented")
+}
+
+func terminationSignal(err error) (os.Signal, bool) {
+ panic("not implemented")
+}
+
+func isCrashSignal(signal os.Signal) bool {
+ panic("not implemented")
+}
diff --git a/src/internal/fuzz/sys_windows.go b/src/internal/fuzz/sys_windows.go
new file mode 100644
index 0000000..fabf954
--- /dev/null
+++ b/src/internal/fuzz/sys_windows.go
@@ -0,0 +1,152 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+import (
+ "fmt"
+ "os"
+ "os/exec"
+ "reflect"
+ "syscall"
+ "unsafe"
+)
+
+type sharedMemSys struct {
+ mapObj syscall.Handle
+}
+
+func sharedMemMapFile(f *os.File, size int, removeOnClose bool) (mem *sharedMem, err error) {
+ defer func() {
+ if err != nil {
+ err = fmt.Errorf("mapping temporary file %s: %w", f.Name(), err)
+ }
+ }()
+
+ // Create a file mapping object. The object itself is not shared.
+ mapObj, err := syscall.CreateFileMapping(
+ syscall.Handle(f.Fd()), // fhandle
+ nil, // sa
+ syscall.PAGE_READWRITE, // prot
+ 0, // maxSizeHigh
+ 0, // maxSizeLow
+ nil, // name
+ )
+ if err != nil {
+ return nil, err
+ }
+
+ // Create a view from the file mapping object.
+ access := uint32(syscall.FILE_MAP_READ | syscall.FILE_MAP_WRITE)
+ addr, err := syscall.MapViewOfFile(
+ mapObj, // handle
+ access, // access
+ 0, // offsetHigh
+ 0, // offsetLow
+ uintptr(size), // length
+ )
+ if err != nil {
+ syscall.CloseHandle(mapObj)
+ return nil, err
+ }
+
+ var region []byte
+ header := (*reflect.SliceHeader)(unsafe.Pointer(®ion))
+ header.Data = addr
+ header.Len = size
+ header.Cap = size
+ return &sharedMem{
+ f: f,
+ region: region,
+ removeOnClose: removeOnClose,
+ sys: sharedMemSys{mapObj: mapObj},
+ }, nil
+}
+
+// Close unmaps the shared memory and closes the temporary file. If this
+// sharedMem was created with sharedMemTempFile, Close also removes the file.
+func (m *sharedMem) Close() error {
+ // Attempt all operations, even if we get an error for an earlier operation.
+ // os.File.Close may fail due to I/O errors, but we still want to delete
+ // the temporary file.
+ var errs []error
+ errs = append(errs,
+ syscall.UnmapViewOfFile(uintptr(unsafe.Pointer(&m.region[0]))),
+ syscall.CloseHandle(m.sys.mapObj),
+ m.f.Close())
+ if m.removeOnClose {
+ errs = append(errs, os.Remove(m.f.Name()))
+ }
+ for _, err := range errs {
+ if err != nil {
+ return err
+ }
+ }
+ return nil
+}
+
+// setWorkerComm configures communciation channels on the cmd that will
+// run a worker process.
+func setWorkerComm(cmd *exec.Cmd, comm workerComm) {
+ mem := <-comm.memMu
+ memName := mem.f.Name()
+ comm.memMu <- mem
+ syscall.SetHandleInformation(syscall.Handle(comm.fuzzIn.Fd()), syscall.HANDLE_FLAG_INHERIT, 1)
+ syscall.SetHandleInformation(syscall.Handle(comm.fuzzOut.Fd()), syscall.HANDLE_FLAG_INHERIT, 1)
+ cmd.Env = append(cmd.Env, fmt.Sprintf("GO_TEST_FUZZ_WORKER_HANDLES=%x,%x,%q", comm.fuzzIn.Fd(), comm.fuzzOut.Fd(), memName))
+ cmd.SysProcAttr = &syscall.SysProcAttr{AdditionalInheritedHandles: []syscall.Handle{syscall.Handle(comm.fuzzIn.Fd()), syscall.Handle(comm.fuzzOut.Fd())}}
+}
+
+// getWorkerComm returns communication channels in the worker process.
+func getWorkerComm() (comm workerComm, err error) {
+ v := os.Getenv("GO_TEST_FUZZ_WORKER_HANDLES")
+ if v == "" {
+ return workerComm{}, fmt.Errorf("GO_TEST_FUZZ_WORKER_HANDLES not set")
+ }
+ var fuzzInFD, fuzzOutFD uintptr
+ var memName string
+ if _, err := fmt.Sscanf(v, "%x,%x,%q", &fuzzInFD, &fuzzOutFD, &memName); err != nil {
+ return workerComm{}, fmt.Errorf("parsing GO_TEST_FUZZ_WORKER_HANDLES=%s: %v", v, err)
+ }
+
+ fuzzIn := os.NewFile(fuzzInFD, "fuzz_in")
+ fuzzOut := os.NewFile(fuzzOutFD, "fuzz_out")
+ tmpFile, err := os.OpenFile(memName, os.O_RDWR, 0)
+ if err != nil {
+ return workerComm{}, fmt.Errorf("worker opening temp file: %w", err)
+ }
+ fi, err := tmpFile.Stat()
+ if err != nil {
+ return workerComm{}, fmt.Errorf("worker checking temp file size: %w", err)
+ }
+ size := int(fi.Size())
+ if int64(size) != fi.Size() {
+ return workerComm{}, fmt.Errorf("fuzz temp file exceeds maximum size")
+ }
+ removeOnClose := false
+ mem, err := sharedMemMapFile(tmpFile, size, removeOnClose)
+ if err != nil {
+ return workerComm{}, err
+ }
+ memMu := make(chan *sharedMem, 1)
+ memMu <- mem
+
+ return workerComm{fuzzIn: fuzzIn, fuzzOut: fuzzOut, memMu: memMu}, nil
+}
+
+func isInterruptError(err error) bool {
+ // On Windows, we can't tell whether the process was interrupted by the error
+ // returned by Wait. It looks like an ExitError with status 1.
+ return false
+}
+
+// terminationSignal returns -1 and false because Windows doesn't have signals.
+func terminationSignal(err error) (os.Signal, bool) {
+ return syscall.Signal(-1), false
+}
+
+// isCrashSignal is not implemented because Windows doesn't have signals.
+func isCrashSignal(signal os.Signal) bool {
+ panic("not implemented: no signals on windows")
+}
diff --git a/src/internal/fuzz/trace.go b/src/internal/fuzz/trace.go
new file mode 100644
index 0000000..f70b1a6
--- /dev/null
+++ b/src/internal/fuzz/trace.go
@@ -0,0 +1,29 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !libfuzzer
+
+package fuzz
+
+import _ "unsafe" // for go:linkname
+
+//go:linkname libfuzzerTraceCmp1 runtime.libfuzzerTraceCmp1
+//go:linkname libfuzzerTraceCmp2 runtime.libfuzzerTraceCmp2
+//go:linkname libfuzzerTraceCmp4 runtime.libfuzzerTraceCmp4
+//go:linkname libfuzzerTraceCmp8 runtime.libfuzzerTraceCmp8
+
+//go:linkname libfuzzerTraceConstCmp1 runtime.libfuzzerTraceConstCmp1
+//go:linkname libfuzzerTraceConstCmp2 runtime.libfuzzerTraceConstCmp2
+//go:linkname libfuzzerTraceConstCmp4 runtime.libfuzzerTraceConstCmp4
+//go:linkname libfuzzerTraceConstCmp8 runtime.libfuzzerTraceConstCmp8
+
+func libfuzzerTraceCmp1(arg0, arg1 uint8) {}
+func libfuzzerTraceCmp2(arg0, arg1 uint16) {}
+func libfuzzerTraceCmp4(arg0, arg1 uint32) {}
+func libfuzzerTraceCmp8(arg0, arg1 uint64) {}
+
+func libfuzzerTraceConstCmp1(arg0, arg1 uint8) {}
+func libfuzzerTraceConstCmp2(arg0, arg1 uint16) {}
+func libfuzzerTraceConstCmp4(arg0, arg1 uint32) {}
+func libfuzzerTraceConstCmp8(arg0, arg1 uint64) {}
diff --git a/src/internal/fuzz/worker.go b/src/internal/fuzz/worker.go
new file mode 100644
index 0000000..da82a95
--- /dev/null
+++ b/src/internal/fuzz/worker.go
@@ -0,0 +1,1160 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+import (
+ "bytes"
+ "context"
+ "crypto/sha256"
+ "encoding/json"
+ "errors"
+ "fmt"
+ "io"
+ "io/ioutil"
+ "os"
+ "os/exec"
+ "runtime"
+ "sync"
+ "time"
+)
+
+const (
+ // workerFuzzDuration is the amount of time a worker can spend testing random
+ // variations of an input given by the coordinator.
+ workerFuzzDuration = 100 * time.Millisecond
+
+ // workerTimeoutDuration is the amount of time a worker can go without
+ // responding to the coordinator before being stopped.
+ workerTimeoutDuration = 1 * time.Second
+
+ // workerExitCode is used as an exit code by fuzz worker processes after an internal error.
+ // This distinguishes internal errors from uncontrolled panics and other crashes.
+ // Keep in sync with internal/fuzz.workerExitCode.
+ workerExitCode = 70
+
+ // workerSharedMemSize is the maximum size of the shared memory file used to
+ // communicate with workers. This limits the size of fuzz inputs.
+ workerSharedMemSize = 100 << 20 // 100 MB
+)
+
+// worker manages a worker process running a test binary. The worker object
+// exists only in the coordinator (the process started by 'go test -fuzz').
+// workerClient is used by the coordinator to send RPCs to the worker process,
+// which handles them with workerServer.
+type worker struct {
+ dir string // working directory, same as package directory
+ binPath string // path to test executable
+ args []string // arguments for test executable
+ env []string // environment for test executable
+
+ coordinator *coordinator
+
+ memMu chan *sharedMem // mutex guarding shared memory with worker; persists across processes.
+
+ cmd *exec.Cmd // current worker process
+ client *workerClient // used to communicate with worker process
+ waitErr error // last error returned by wait, set before termC is closed.
+ interrupted bool // true after stop interrupts a running worker.
+ termC chan struct{} // closed by wait when worker process terminates
+}
+
+func newWorker(c *coordinator, dir, binPath string, args, env []string) (*worker, error) {
+ mem, err := sharedMemTempFile(workerSharedMemSize)
+ if err != nil {
+ return nil, err
+ }
+ memMu := make(chan *sharedMem, 1)
+ memMu <- mem
+ return &worker{
+ dir: dir,
+ binPath: binPath,
+ args: args,
+ env: env[:len(env):len(env)], // copy on append to ensure workers don't overwrite each other.
+ coordinator: c,
+ memMu: memMu,
+ }, nil
+}
+
+// cleanup releases persistent resources associated with the worker.
+func (w *worker) cleanup() error {
+ mem := <-w.memMu
+ if mem == nil {
+ return nil
+ }
+ close(w.memMu)
+ return mem.Close()
+}
+
+// coordinate runs the test binary to perform fuzzing.
+//
+// coordinate loops until ctx is cancelled or a fatal error is encountered.
+// If a test process terminates unexpectedly while fuzzing, coordinate will
+// attempt to restart and continue unless the termination can be attributed
+// to an interruption (from a timer or the user).
+//
+// While looping, coordinate receives inputs from the coordinator, passes
+// those inputs to the worker process, then passes the results back to
+// the coordinator.
+func (w *worker) coordinate(ctx context.Context) error {
+ // Main event loop.
+ for {
+ // Start or restart the worker if it's not running.
+ if !w.isRunning() {
+ if err := w.startAndPing(ctx); err != nil {
+ return err
+ }
+ }
+
+ select {
+ case <-ctx.Done():
+ // Worker was told to stop.
+ err := w.stop()
+ if err != nil && !w.interrupted && !isInterruptError(err) {
+ return err
+ }
+ return ctx.Err()
+
+ case <-w.termC:
+ // Worker process terminated unexpectedly while waiting for input.
+ err := w.stop()
+ if w.interrupted {
+ panic("worker interrupted after unexpected termination")
+ }
+ if err == nil || isInterruptError(err) {
+ // Worker stopped, either by exiting with status 0 or after being
+ // interrupted with a signal that was not sent by the coordinator.
+ //
+ // When the user presses ^C, on POSIX platforms, SIGINT is delivered to
+ // all processes in the group concurrently, and the worker may see it
+ // before the coordinator. The worker should exit 0 gracefully (in
+ // theory).
+ //
+ // This condition is probably intended by the user, so suppress
+ // the error.
+ return nil
+ }
+ if exitErr, ok := err.(*exec.ExitError); ok && exitErr.ExitCode() == workerExitCode {
+ // Worker exited with a code indicating F.Fuzz was not called correctly,
+ // for example, F.Fail was called first.
+ return fmt.Errorf("fuzzing process exited unexpectedly due to an internal failure: %w", err)
+ }
+ // Worker exited non-zero or was terminated by a non-interrupt signal
+ // (for example, SIGSEGV) while fuzzing.
+ return fmt.Errorf("fuzzing process terminated unexpectedly: %w", err)
+ // TODO(jayconrod,katiehockman): if -keepfuzzing, restart worker.
+
+ case input := <-w.coordinator.inputC:
+ // Received input from coordinator.
+ args := fuzzArgs{
+ Limit: input.limit,
+ Timeout: input.timeout,
+ Warmup: input.warmup,
+ CoverageData: input.coverageData,
+ }
+ entry, resp, err := w.client.fuzz(ctx, input.entry, args)
+ if err != nil {
+ // Error communicating with worker.
+ w.stop()
+ if ctx.Err() != nil {
+ // Timeout or interruption.
+ return ctx.Err()
+ }
+ if w.interrupted {
+ // Communication error before we stopped the worker.
+ // Report an error, but don't record a crasher.
+ return fmt.Errorf("communicating with fuzzing process: %v", err)
+ }
+ if w.waitErr == nil || isInterruptError(w.waitErr) {
+ // Worker stopped, either by exiting with status 0 or after being
+ // interrupted with a signal (not sent by coordinator). See comment in
+ // termC case above.
+ //
+ // Since we expect I/O errors around interrupts, ignore this error.
+ return nil
+ }
+ if sig, ok := terminationSignal(w.waitErr); ok && !isCrashSignal(sig) {
+ // Worker terminated by a signal that probably wasn't caused by a
+ // specific input to the fuzz function. For example, on Linux,
+ // the kernel (OOM killer) may send SIGKILL to a process using a lot
+ // of memory. Or the shell might send SIGHUP when the terminal
+ // is closed. Don't record a crasher.
+ return fmt.Errorf("fuzzing process terminated by unexpected signal; no crash will be recorded: %v", w.waitErr)
+ }
+ // Unexpected termination. Set error message and fall through.
+ // We'll restart the worker on the next iteration.
+ resp.Err = fmt.Sprintf("fuzzing process terminated unexpectedly: %v", w.waitErr)
+ }
+ result := fuzzResult{
+ limit: input.limit,
+ count: resp.Count,
+ totalDuration: resp.TotalDuration,
+ entryDuration: resp.InterestingDuration,
+ entry: entry,
+ crasherMsg: resp.Err,
+ coverageData: resp.CoverageData,
+ }
+ w.coordinator.resultC <- result
+
+ case input := <-w.coordinator.minimizeC:
+ // Received input to minimize from coordinator.
+ result, err := w.minimize(ctx, input)
+ if err != nil {
+ // Error minimizing. Send back the original input. If it didn't cause
+ // an error before, report it as causing an error now.
+ // TODO: double-check this is handled correctly when
+ // implementing -keepfuzzing.
+ result = fuzzResult{
+ entry: input.entry,
+ crasherMsg: input.crasherMsg,
+ minimizeAttempted: true,
+ limit: input.limit,
+ }
+ if result.crasherMsg == "" {
+ result.crasherMsg = err.Error()
+ }
+ }
+ w.coordinator.resultC <- result
+ }
+ }
+}
+
+// minimize tells a worker process to attempt to find a smaller value that
+// either causes an error (if we started minimizing because we found an input
+// that causes an error) or preserves new coverage (if we started minimizing
+// because we found an input that expands coverage).
+func (w *worker) minimize(ctx context.Context, input fuzzMinimizeInput) (min fuzzResult, err error) {
+ if w.coordinator.opts.MinimizeTimeout != 0 {
+ var cancel func()
+ ctx, cancel = context.WithTimeout(ctx, w.coordinator.opts.MinimizeTimeout)
+ defer cancel()
+ }
+
+ args := minimizeArgs{
+ Limit: input.limit,
+ Timeout: input.timeout,
+ KeepCoverage: input.keepCoverage,
+ }
+ entry, resp, err := w.client.minimize(ctx, input.entry, args)
+ if err != nil {
+ // Error communicating with worker.
+ w.stop()
+ if ctx.Err() != nil || w.interrupted || isInterruptError(w.waitErr) {
+ // Worker was interrupted, possibly by the user pressing ^C.
+ // Normally, workers can handle interrupts and timeouts gracefully and
+ // will return without error. An error here indicates the worker
+ // may not have been in a good state, but the error won't be meaningful
+ // to the user. Just return the original crasher without logging anything.
+ return fuzzResult{
+ entry: input.entry,
+ crasherMsg: input.crasherMsg,
+ coverageData: input.keepCoverage,
+ minimizeAttempted: true,
+ limit: input.limit,
+ }, nil
+ }
+ return fuzzResult{}, fmt.Errorf("fuzzing process terminated unexpectedly while minimizing: %w", w.waitErr)
+ }
+
+ if input.crasherMsg != "" && resp.Err == "" && !resp.Success {
+ return fuzzResult{}, fmt.Errorf("attempted to minimize but could not reproduce")
+ }
+
+ return fuzzResult{
+ entry: entry,
+ crasherMsg: resp.Err,
+ coverageData: resp.CoverageData,
+ minimizeAttempted: true,
+ limit: input.limit,
+ count: resp.Count,
+ totalDuration: resp.Duration,
+ }, nil
+}
+
+func (w *worker) isRunning() bool {
+ return w.cmd != nil
+}
+
+// startAndPing starts the worker process and sends it a message to make sure it
+// can communicate.
+//
+// startAndPing returns an error if any part of this didn't work, including if
+// the context is expired or the worker process was interrupted before it
+// responded. Errors that happen after start but before the ping response
+// likely indicate that the worker did not call F.Fuzz or called F.Fail first.
+// We don't record crashers for these errors.
+func (w *worker) startAndPing(ctx context.Context) error {
+ if ctx.Err() != nil {
+ return ctx.Err()
+ }
+ if err := w.start(); err != nil {
+ return err
+ }
+ if err := w.client.ping(ctx); err != nil {
+ w.stop()
+ if ctx.Err() != nil {
+ return ctx.Err()
+ }
+ if isInterruptError(err) {
+ // User may have pressed ^C before worker responded.
+ return err
+ }
+ // TODO: record and return stderr.
+ return fmt.Errorf("fuzzing process terminated without fuzzing: %w", err)
+ }
+ return nil
+}
+
+// start runs a new worker process.
+//
+// If the process couldn't be started, start returns an error. Start won't
+// return later termination errors from the process if they occur.
+//
+// If the process starts successfully, start returns nil. stop must be called
+// once later to clean up, even if the process terminates on its own.
+//
+// When the process terminates, w.waitErr is set to the error (if any), and
+// w.termC is closed.
+func (w *worker) start() (err error) {
+ if w.isRunning() {
+ panic("worker already started")
+ }
+ w.waitErr = nil
+ w.interrupted = false
+ w.termC = nil
+
+ cmd := exec.Command(w.binPath, w.args...)
+ cmd.Dir = w.dir
+ cmd.Env = w.env[:len(w.env):len(w.env)] // copy on append to ensure workers don't overwrite each other.
+ cmd.Stdout = os.Stdout
+ cmd.Stderr = os.Stderr
+
+ // Create the "fuzz_in" and "fuzz_out" pipes so we can communicate with
+ // the worker. We don't use stdin and stdout, since the test binary may
+ // do something else with those.
+ //
+ // Each pipe has a reader and a writer. The coordinator writes to fuzzInW
+ // and reads from fuzzOutR. The worker inherits fuzzInR and fuzzOutW.
+ // The coordinator closes fuzzInR and fuzzOutW after starting the worker,
+ // since we have no further need of them.
+ fuzzInR, fuzzInW, err := os.Pipe()
+ if err != nil {
+ return err
+ }
+ defer fuzzInR.Close()
+ fuzzOutR, fuzzOutW, err := os.Pipe()
+ if err != nil {
+ fuzzInW.Close()
+ return err
+ }
+ defer fuzzOutW.Close()
+ setWorkerComm(cmd, workerComm{fuzzIn: fuzzInR, fuzzOut: fuzzOutW, memMu: w.memMu})
+
+ // Start the worker process.
+ if err := cmd.Start(); err != nil {
+ fuzzInW.Close()
+ fuzzOutR.Close()
+ return err
+ }
+
+ // Worker started successfully.
+ // After this, w.client owns fuzzInW and fuzzOutR, so w.client.Close must be
+ // called later by stop.
+ w.cmd = cmd
+ w.termC = make(chan struct{})
+ comm := workerComm{fuzzIn: fuzzInW, fuzzOut: fuzzOutR, memMu: w.memMu}
+ m := newMutator()
+ w.client = newWorkerClient(comm, m)
+
+ go func() {
+ w.waitErr = w.cmd.Wait()
+ close(w.termC)
+ }()
+
+ return nil
+}
+
+// stop tells the worker process to exit by closing w.client, then blocks until
+// it terminates. If the worker doesn't terminate after a short time, stop
+// signals it with os.Interrupt (where supported), then os.Kill.
+//
+// stop returns the error the process terminated with, if any (same as
+// w.waitErr).
+//
+// stop must be called at least once after start returns successfully, even if
+// the worker process terminates unexpectedly.
+func (w *worker) stop() error {
+ if w.termC == nil {
+ panic("worker was not started successfully")
+ }
+ select {
+ case <-w.termC:
+ // Worker already terminated.
+ if w.client == nil {
+ // stop already called.
+ return w.waitErr
+ }
+ // Possible unexpected termination.
+ w.client.Close()
+ w.cmd = nil
+ w.client = nil
+ return w.waitErr
+ default:
+ // Worker still running.
+ }
+
+ // Tell the worker to stop by closing fuzz_in. It won't actually stop until it
+ // finishes with earlier calls.
+ closeC := make(chan struct{})
+ go func() {
+ w.client.Close()
+ close(closeC)
+ }()
+
+ sig := os.Interrupt
+ if runtime.GOOS == "windows" {
+ // Per https://golang.org/pkg/os/#Signal, “Interrupt is not implemented on
+ // Windows; using it with os.Process.Signal will return an error.”
+ // Fall back to Kill instead.
+ sig = os.Kill
+ }
+
+ t := time.NewTimer(workerTimeoutDuration)
+ for {
+ select {
+ case <-w.termC:
+ // Worker terminated.
+ t.Stop()
+ <-closeC
+ w.cmd = nil
+ w.client = nil
+ return w.waitErr
+
+ case <-t.C:
+ // Timer fired before worker terminated.
+ w.interrupted = true
+ switch sig {
+ case os.Interrupt:
+ // Try to stop the worker with SIGINT and wait a little longer.
+ w.cmd.Process.Signal(sig)
+ sig = os.Kill
+ t.Reset(workerTimeoutDuration)
+
+ case os.Kill:
+ // Try to stop the worker with SIGKILL and keep waiting.
+ w.cmd.Process.Signal(sig)
+ sig = nil
+ t.Reset(workerTimeoutDuration)
+
+ case nil:
+ // Still waiting. Print a message to let the user know why.
+ fmt.Fprintf(w.coordinator.opts.Log, "waiting for fuzzing process to terminate...\n")
+ }
+ }
+ }
+}
+
+// RunFuzzWorker is called in a worker process to communicate with the
+// coordinator process in order to fuzz random inputs. RunFuzzWorker loops
+// until the coordinator tells it to stop.
+//
+// fn is a wrapper on the fuzz function. It may return an error to indicate
+// a given input "crashed". The coordinator will also record a crasher if
+// the function times out or terminates the process.
+//
+// RunFuzzWorker returns an error if it could not communicate with the
+// coordinator process.
+func RunFuzzWorker(ctx context.Context, fn func(CorpusEntry) error) error {
+ comm, err := getWorkerComm()
+ if err != nil {
+ return err
+ }
+ srv := &workerServer{
+ workerComm: comm,
+ fuzzFn: fn,
+ m: newMutator(),
+ }
+ return srv.serve(ctx)
+}
+
+// call is serialized and sent from the coordinator on fuzz_in. It acts as
+// a minimalist RPC mechanism. Exactly one of its fields must be set to indicate
+// which method to call.
+type call struct {
+ Ping *pingArgs
+ Fuzz *fuzzArgs
+ Minimize *minimizeArgs
+}
+
+// minimizeArgs contains arguments to workerServer.minimize. The value to
+// minimize is already in shared memory.
+type minimizeArgs struct {
+ // Timeout is the time to spend minimizing. This may include time to start up,
+ // especially if the input causes the worker process to terminated, requiring
+ // repeated restarts.
+ Timeout time.Duration
+
+ // Limit is the maximum number of values to test, without spending more time
+ // than Duration. 0 indicates no limit.
+ Limit int64
+
+ // KeepCoverage is a set of coverage counters the worker should attempt to
+ // keep in minimized values. When provided, the worker will reject inputs that
+ // don't cause at least one of these bits to be set.
+ KeepCoverage []byte
+}
+
+// minimizeResponse contains results from workerServer.minimize.
+type minimizeResponse struct {
+ // Success is true if the worker found a smaller input, stored in shared
+ // memory, that was "interesting" for the same reason as the original input.
+ // If minimizeArgs.KeepCoverage was set, the minimized input preserved at
+ // least one coverage bit and did not cause an error. Otherwise, the
+ // minimized input caused some error, recorded in Err.
+ Success bool
+
+ // Err is the error string caused by the value in shared memory, if any.
+ Err string
+
+ // CoverageData is the set of coverage bits activated by the minimized value
+ // in shared memory. When set, it contains at least one bit from KeepCoverage.
+ // CoverageData will be nil if Err is set or if minimization failed.
+ CoverageData []byte
+
+ // Duration is the time spent minimizing, not including starting or cleaning up.
+ Duration time.Duration
+
+ // Count is the number of values tested.
+ Count int64
+}
+
+// fuzzArgs contains arguments to workerServer.fuzz. The value to fuzz is
+// passed in shared memory.
+type fuzzArgs struct {
+ // Timeout is the time to spend fuzzing, not including starting or
+ // cleaning up.
+ Timeout time.Duration
+
+ // Limit is the maximum number of values to test, without spending more time
+ // than Duration. 0 indicates no limit.
+ Limit int64
+
+ // Warmup indicates whether this is part of a warmup run, meaning that
+ // fuzzing should not occur. If coverageEnabled is true, then coverage data
+ // should be reported.
+ Warmup bool
+
+ // CoverageData is the coverage data. If set, the worker should update its
+ // local coverage data prior to fuzzing.
+ CoverageData []byte
+}
+
+// fuzzResponse contains results from workerServer.fuzz.
+type fuzzResponse struct {
+ // Duration is the time spent fuzzing, not including starting or cleaning up.
+ TotalDuration time.Duration
+ InterestingDuration time.Duration
+
+ // Count is the number of values tested.
+ Count int64
+
+ // CoverageData is set if the value in shared memory expands coverage
+ // and therefore may be interesting to the coordinator.
+ CoverageData []byte
+
+ // Err is the error string caused by the value in shared memory, which is
+ // non-empty if the value in shared memory caused a crash.
+ Err string
+}
+
+// pingArgs contains arguments to workerServer.ping.
+type pingArgs struct{}
+
+// pingResponse contains results from workerServer.ping.
+type pingResponse struct{}
+
+// workerComm holds pipes and shared memory used for communication
+// between the coordinator process (client) and a worker process (server).
+// These values are unique to each worker; they are shared only with the
+// coordinator, not with other workers.
+//
+// Access to shared memory is synchronized implicitly over the RPC protocol
+// implemented in workerServer and workerClient. During a call, the client
+// (worker) has exclusive access to shared memory; at other times, the server
+// (coordinator) has exclusive access.
+type workerComm struct {
+ fuzzIn, fuzzOut *os.File
+ memMu chan *sharedMem // mutex guarding shared memory
+}
+
+// workerServer is a minimalist RPC server, run by fuzz worker processes.
+// It allows the coordinator process (using workerClient) to call methods in a
+// worker process. This system allows the coordinator to run multiple worker
+// processes in parallel and to collect inputs that caused crashes from shared
+// memory after a worker process terminates unexpectedly.
+type workerServer struct {
+ workerComm
+ m *mutator
+
+ // coverageMask is the local coverage data for the worker. It is
+ // periodically updated to reflect the data in the coordinator when new
+ // coverage is found.
+ coverageMask []byte
+
+ // fuzzFn runs the worker's fuzz function on the given input and returns
+ // an error if it finds a crasher (the process may also exit or crash).
+ fuzzFn func(CorpusEntry) error
+}
+
+// serve reads serialized RPC messages on fuzzIn. When serve receives a message,
+// it calls the corresponding method, then sends the serialized result back
+// on fuzzOut.
+//
+// serve handles RPC calls synchronously; it will not attempt to read a message
+// until the previous call has finished.
+//
+// serve returns errors that occurred when communicating over pipes. serve
+// does not return errors from method calls; those are passed through serialized
+// responses.
+func (ws *workerServer) serve(ctx context.Context) error {
+ enc := json.NewEncoder(ws.fuzzOut)
+ dec := json.NewDecoder(&contextReader{ctx: ctx, r: ws.fuzzIn})
+ for {
+ var c call
+ if err := dec.Decode(&c); err != nil {
+ if err == io.EOF || err == ctx.Err() {
+ return nil
+ } else {
+ return err
+ }
+ }
+
+ var resp interface{}
+ switch {
+ case c.Fuzz != nil:
+ resp = ws.fuzz(ctx, *c.Fuzz)
+ case c.Minimize != nil:
+ resp = ws.minimize(ctx, *c.Minimize)
+ case c.Ping != nil:
+ resp = ws.ping(ctx, *c.Ping)
+ default:
+ return errors.New("no arguments provided for any call")
+ }
+
+ if err := enc.Encode(resp); err != nil {
+ return err
+ }
+ }
+}
+
+// fuzz runs the test function on random variations of the input value in shared
+// memory for a limited duration or number of iterations.
+//
+// fuzz returns early if it finds an input that crashes the fuzz function (with
+// fuzzResponse.Err set) or an input that expands coverage (with
+// fuzzResponse.InterestingDuration set).
+//
+// fuzz does not modify the input in shared memory. Instead, it saves the
+// initial PRNG state in shared memory and increments a counter in shared
+// memory before each call to the test function. The caller may reconstruct
+// the crashing input with this information, since the PRNG is deterministic.
+func (ws *workerServer) fuzz(ctx context.Context, args fuzzArgs) (resp fuzzResponse) {
+ if args.CoverageData != nil {
+ if ws.coverageMask != nil && len(args.CoverageData) != len(ws.coverageMask) {
+ panic(fmt.Sprintf("unexpected size for CoverageData: got %d, expected %d", len(args.CoverageData), len(ws.coverageMask)))
+ }
+ ws.coverageMask = args.CoverageData
+ }
+ start := time.Now()
+ defer func() { resp.TotalDuration = time.Since(start) }()
+
+ if args.Timeout != 0 {
+ var cancel func()
+ ctx, cancel = context.WithTimeout(ctx, args.Timeout)
+ defer cancel()
+ }
+ mem := <-ws.memMu
+ ws.m.r.save(&mem.header().randState, &mem.header().randInc)
+ defer func() {
+ resp.Count = mem.header().count
+ ws.memMu <- mem
+ }()
+ if args.Limit > 0 && mem.header().count >= args.Limit {
+ panic(fmt.Sprintf("mem.header().count %d already exceeds args.Limit %d", mem.header().count, args.Limit))
+ }
+
+ vals, err := unmarshalCorpusFile(mem.valueCopy())
+ if err != nil {
+ panic(err)
+ }
+
+ shouldStop := func() bool {
+ return args.Limit > 0 && mem.header().count >= args.Limit
+ }
+ fuzzOnce := func(entry CorpusEntry) (dur time.Duration, cov []byte, errMsg string) {
+ mem.header().count++
+ start := time.Now()
+ err := ws.fuzzFn(entry)
+ dur = time.Since(start)
+ if err != nil {
+ errMsg = err.Error()
+ if errMsg == "" {
+ errMsg = "fuzz function failed with no input"
+ }
+ return dur, nil, errMsg
+ }
+ if ws.coverageMask != nil && countNewCoverageBits(ws.coverageMask, coverageSnapshot) > 0 {
+ return dur, coverageSnapshot, ""
+ }
+ return dur, nil, ""
+ }
+
+ if args.Warmup {
+ dur, _, errMsg := fuzzOnce(CorpusEntry{Values: vals})
+ if errMsg != "" {
+ resp.Err = errMsg
+ return resp
+ }
+ resp.InterestingDuration = dur
+ if coverageEnabled {
+ resp.CoverageData = coverageSnapshot
+ }
+ return resp
+ }
+
+ for {
+ select {
+ case <-ctx.Done():
+ return resp
+
+ default:
+ ws.m.mutate(vals, cap(mem.valueRef()))
+ entry := CorpusEntry{Values: vals}
+ dur, cov, errMsg := fuzzOnce(entry)
+ if errMsg != "" {
+ resp.Err = errMsg
+ return resp
+ }
+ if cov != nil {
+ // Found new coverage. Before reporting to the coordinator,
+ // run the same values once more to deflake.
+ if !shouldStop() {
+ dur, cov, errMsg = fuzzOnce(entry)
+ if errMsg != "" {
+ resp.Err = errMsg
+ return resp
+ }
+ }
+ if cov != nil {
+ resp.CoverageData = cov
+ resp.InterestingDuration = dur
+ return resp
+ }
+ }
+ if shouldStop() {
+ return resp
+ }
+ }
+ }
+}
+
+func (ws *workerServer) minimize(ctx context.Context, args minimizeArgs) (resp minimizeResponse) {
+ start := time.Now()
+ defer func() { resp.Duration = time.Now().Sub(start) }()
+ mem := <-ws.memMu
+ defer func() { ws.memMu <- mem }()
+ vals, err := unmarshalCorpusFile(mem.valueCopy())
+ if err != nil {
+ panic(err)
+ }
+ if args.Timeout != 0 {
+ var cancel func()
+ ctx, cancel = context.WithTimeout(ctx, args.Timeout)
+ defer cancel()
+ }
+
+ // Minimize the values in vals, then write to shared memory. We only write
+ // to shared memory after completing minimization. If the worker terminates
+ // unexpectedly before then, the coordinator will use the original input.
+ resp.Success, err = ws.minimizeInput(ctx, vals, &mem.header().count, args.Limit, args.KeepCoverage)
+ if resp.Success {
+ writeToMem(vals, mem)
+ }
+ if err != nil {
+ resp.Err = err.Error()
+ } else if resp.Success {
+ resp.CoverageData = coverageSnapshot
+ }
+ return resp
+}
+
+// minimizeInput applies a series of minimizing transformations on the provided
+// vals, ensuring that each minimization still causes an error in fuzzFn. Before
+// every call to fuzzFn, it marshals the new vals and writes it to the provided
+// mem just in case an unrecoverable error occurs. It uses the context to
+// determine how long to run, stopping once closed. It returns a bool
+// indicating whether minimization was successful and an error if one was found.
+func (ws *workerServer) minimizeInput(ctx context.Context, vals []interface{}, count *int64, limit int64, keepCoverage []byte) (success bool, retErr error) {
+ wantError := keepCoverage == nil
+ shouldStop := func() bool {
+ return ctx.Err() != nil ||
+ (limit > 0 && *count >= limit) ||
+ (retErr != nil && !wantError)
+ }
+ if shouldStop() {
+ return false, nil
+ }
+
+ // Check that the original value preserves coverage or causes an error.
+ // If not, then whatever caused us to think the value was interesting may
+ // have been a flake, and we can't minimize it.
+ *count++
+ if retErr = ws.fuzzFn(CorpusEntry{Values: vals}); retErr == nil && wantError {
+ return false, nil
+ } else if retErr != nil && !wantError {
+ return false, retErr
+ } else if keepCoverage != nil && !hasCoverageBit(keepCoverage, coverageSnapshot) {
+ return false, nil
+ }
+
+ var valI int
+ // tryMinimized runs the fuzz function with candidate replacing the value
+ // at index valI. tryMinimized returns whether the input with candidate is
+ // interesting for the same reason as the original input: it returns
+ // an error if one was expected, or it preserves coverage.
+ tryMinimized := func(candidate interface{}) bool {
+ prev := vals[valI]
+ // Set vals[valI] to the candidate after it has been
+ // properly cast. We know that candidate must be of
+ // the same type as prev, so use that as a reference.
+ switch c := candidate.(type) {
+ case float64:
+ switch prev.(type) {
+ case float32:
+ vals[valI] = float32(c)
+ case float64:
+ vals[valI] = c
+ default:
+ panic("impossible")
+ }
+ case uint:
+ switch prev.(type) {
+ case uint:
+ vals[valI] = c
+ case uint8:
+ vals[valI] = uint8(c)
+ case uint16:
+ vals[valI] = uint16(c)
+ case uint32:
+ vals[valI] = uint32(c)
+ case uint64:
+ vals[valI] = uint64(c)
+ case int:
+ vals[valI] = int(c)
+ case int8:
+ vals[valI] = int8(c)
+ case int16:
+ vals[valI] = int16(c)
+ case int32:
+ vals[valI] = int32(c)
+ case int64:
+ vals[valI] = int64(c)
+ default:
+ panic("impossible")
+ }
+ case []byte:
+ switch prev.(type) {
+ case []byte:
+ vals[valI] = c
+ case string:
+ vals[valI] = string(c)
+ default:
+ panic("impossible")
+ }
+ default:
+ panic("impossible")
+ }
+ *count++
+ err := ws.fuzzFn(CorpusEntry{Values: vals})
+ if err != nil {
+ retErr = err
+ return wantError
+ }
+ if keepCoverage != nil && hasCoverageBit(keepCoverage, coverageSnapshot) {
+ return true
+ }
+ vals[valI] = prev
+ return false
+ }
+
+ for valI = range vals {
+ if shouldStop() {
+ break
+ }
+ switch v := vals[valI].(type) {
+ case bool:
+ continue // can't minimize
+ case float32:
+ minimizeFloat(float64(v), tryMinimized, shouldStop)
+ case float64:
+ minimizeFloat(v, tryMinimized, shouldStop)
+ case uint:
+ minimizeInteger(v, tryMinimized, shouldStop)
+ case uint8:
+ minimizeInteger(uint(v), tryMinimized, shouldStop)
+ case uint16:
+ minimizeInteger(uint(v), tryMinimized, shouldStop)
+ case uint32:
+ minimizeInteger(uint(v), tryMinimized, shouldStop)
+ case uint64:
+ if uint64(uint(v)) != v {
+ // Skip minimizing a uint64 on 32 bit platforms, since we'll truncate the
+ // value when casting
+ continue
+ }
+ minimizeInteger(uint(v), tryMinimized, shouldStop)
+ case int:
+ minimizeInteger(uint(v), tryMinimized, shouldStop)
+ case int8:
+ minimizeInteger(uint(v), tryMinimized, shouldStop)
+ case int16:
+ minimizeInteger(uint(v), tryMinimized, shouldStop)
+ case int32:
+ minimizeInteger(uint(v), tryMinimized, shouldStop)
+ case int64:
+ if int64(int(v)) != v {
+ // Skip minimizing a int64 on 32 bit platforms, since we'll truncate the
+ // value when casting
+ continue
+ }
+ minimizeInteger(uint(v), tryMinimized, shouldStop)
+ case string:
+ minimizeBytes([]byte(v), tryMinimized, shouldStop)
+ case []byte:
+ minimizeBytes(v, tryMinimized, shouldStop)
+ default:
+ panic("unreachable")
+ }
+ }
+ return (wantError || retErr == nil), retErr
+}
+
+func writeToMem(vals []interface{}, mem *sharedMem) {
+ b := marshalCorpusFile(vals...)
+ mem.setValue(b)
+}
+
+// ping does nothing. The coordinator calls this method to ensure the worker
+// has called F.Fuzz and can communicate.
+func (ws *workerServer) ping(ctx context.Context, args pingArgs) pingResponse {
+ return pingResponse{}
+}
+
+// workerClient is a minimalist RPC client. The coordinator process uses a
+// workerClient to call methods in each worker process (handled by
+// workerServer).
+type workerClient struct {
+ workerComm
+ mu sync.Mutex
+ m *mutator
+}
+
+func newWorkerClient(comm workerComm, m *mutator) *workerClient {
+ return &workerClient{workerComm: comm, m: m}
+}
+
+// Close shuts down the connection to the RPC server (the worker process) by
+// closing fuzz_in. Close drains fuzz_out (avoiding a SIGPIPE in the worker),
+// and closes it after the worker process closes the other end.
+func (wc *workerClient) Close() error {
+ wc.mu.Lock()
+ defer wc.mu.Unlock()
+
+ // Close fuzzIn. This signals to the server that there are no more calls,
+ // and it should exit.
+ if err := wc.fuzzIn.Close(); err != nil {
+ wc.fuzzOut.Close()
+ return err
+ }
+
+ // Drain fuzzOut and close it. When the server exits, the kernel will close
+ // its end of fuzzOut, and we'll get EOF.
+ if _, err := io.Copy(ioutil.Discard, wc.fuzzOut); err != nil {
+ wc.fuzzOut.Close()
+ return err
+ }
+ return wc.fuzzOut.Close()
+}
+
+// errSharedMemClosed is returned by workerClient methods that cannot access
+// shared memory because it was closed and unmapped by another goroutine. That
+// can happen when worker.cleanup is called in the worker goroutine while a
+// workerClient.fuzz call runs concurrently.
+//
+// This error should not be reported. It indicates the operation was
+// interrupted.
+var errSharedMemClosed = errors.New("internal error: shared memory was closed and unmapped")
+
+// minimize tells the worker to call the minimize method. See
+// workerServer.minimize.
+func (wc *workerClient) minimize(ctx context.Context, entryIn CorpusEntry, args minimizeArgs) (entryOut CorpusEntry, resp minimizeResponse, err error) {
+ wc.mu.Lock()
+ defer wc.mu.Unlock()
+
+ mem, ok := <-wc.memMu
+ if !ok {
+ return CorpusEntry{}, minimizeResponse{}, errSharedMemClosed
+ }
+ mem.header().count = 0
+ inp, err := CorpusEntryData(entryIn)
+ if err != nil {
+ return CorpusEntry{}, minimizeResponse{}, err
+ }
+ mem.setValue(inp)
+ wc.memMu <- mem
+
+ c := call{Minimize: &args}
+ callErr := wc.callLocked(ctx, c, &resp)
+ mem, ok = <-wc.memMu
+ if !ok {
+ return CorpusEntry{}, minimizeResponse{}, errSharedMemClosed
+ }
+ defer func() { wc.memMu <- mem }()
+ resp.Count = mem.header().count
+ if resp.Success {
+ entryOut.Data = mem.valueCopy()
+ entryOut.Values, err = unmarshalCorpusFile(entryOut.Data)
+ h := sha256.Sum256(entryOut.Data)
+ name := fmt.Sprintf("%x", h[:4])
+ entryOut.Name = name
+ entryOut.Parent = entryIn.Parent
+ entryOut.Generation = entryIn.Generation
+ if err != nil {
+ panic(fmt.Sprintf("workerClient.minimize unmarshaling minimized value: %v", err))
+ }
+ } else {
+ // Did not minimize, but the original input may still be interesting,
+ // for example, if there was an error.
+ entryOut = entryIn
+ }
+
+ return entryOut, resp, callErr
+}
+
+// fuzz tells the worker to call the fuzz method. See workerServer.fuzz.
+func (wc *workerClient) fuzz(ctx context.Context, entryIn CorpusEntry, args fuzzArgs) (entryOut CorpusEntry, resp fuzzResponse, err error) {
+ wc.mu.Lock()
+ defer wc.mu.Unlock()
+
+ mem, ok := <-wc.memMu
+ if !ok {
+ return CorpusEntry{}, fuzzResponse{}, errSharedMemClosed
+ }
+ mem.header().count = 0
+ inp, err := CorpusEntryData(entryIn)
+ if err != nil {
+ return CorpusEntry{}, fuzzResponse{}, err
+ }
+ mem.setValue(inp)
+ wc.memMu <- mem
+
+ c := call{Fuzz: &args}
+ callErr := wc.callLocked(ctx, c, &resp)
+ mem, ok = <-wc.memMu
+ if !ok {
+ return CorpusEntry{}, fuzzResponse{}, errSharedMemClosed
+ }
+ defer func() { wc.memMu <- mem }()
+ resp.Count = mem.header().count
+
+ if !bytes.Equal(inp, mem.valueRef()) {
+ panic("workerServer.fuzz modified input")
+ }
+ needEntryOut := callErr != nil || resp.Err != "" ||
+ (!args.Warmup && resp.CoverageData != nil)
+ if needEntryOut {
+ valuesOut, err := unmarshalCorpusFile(inp)
+ if err != nil {
+ panic(fmt.Sprintf("unmarshaling fuzz input value after call: %v", err))
+ }
+ wc.m.r.restore(mem.header().randState, mem.header().randInc)
+ if !args.Warmup {
+ // Only mutate the valuesOut if fuzzing actually occurred.
+ for i := int64(0); i < mem.header().count; i++ {
+ wc.m.mutate(valuesOut, cap(mem.valueRef()))
+ }
+ }
+ dataOut := marshalCorpusFile(valuesOut...)
+
+ h := sha256.Sum256(dataOut)
+ name := fmt.Sprintf("%x", h[:4])
+ entryOut = CorpusEntry{
+ Name: name,
+ Parent: entryIn.Name,
+ Data: dataOut,
+ Generation: entryIn.Generation + 1,
+ }
+ if args.Warmup {
+ // The bytes weren't mutated, so if entryIn was a seed corpus value,
+ // then entryOut is too.
+ entryOut.IsSeed = entryIn.IsSeed
+ }
+ }
+
+ return entryOut, resp, callErr
+}
+
+// ping tells the worker to call the ping method. See workerServer.ping.
+func (wc *workerClient) ping(ctx context.Context) error {
+ wc.mu.Lock()
+ defer wc.mu.Unlock()
+ c := call{Ping: &pingArgs{}}
+ var resp pingResponse
+ return wc.callLocked(ctx, c, &resp)
+}
+
+// callLocked sends an RPC from the coordinator to the worker process and waits
+// for the response. The callLocked may be cancelled with ctx.
+func (wc *workerClient) callLocked(ctx context.Context, c call, resp interface{}) (err error) {
+ enc := json.NewEncoder(wc.fuzzIn)
+ dec := json.NewDecoder(&contextReader{ctx: ctx, r: wc.fuzzOut})
+ if err := enc.Encode(c); err != nil {
+ return err
+ }
+ return dec.Decode(resp)
+}
+
+// contextReader wraps a Reader with a Context. If the context is cancelled
+// while the underlying reader is blocked, Read returns immediately.
+//
+// This is useful for reading from a pipe. Closing a pipe file descriptor does
+// not unblock pending Reads on that file descriptor. All copies of the pipe's
+// other file descriptor (the write end) must be closed in all processes that
+// inherit it. This is difficult to do correctly in the situation we care about
+// (process group termination).
+type contextReader struct {
+ ctx context.Context
+ r io.Reader
+}
+
+func (cr *contextReader) Read(b []byte) (n int, err error) {
+ if err := cr.ctx.Err(); err != nil {
+ return 0, err
+ }
+ done := make(chan struct{})
+
+ // This goroutine may stay blocked after Read returns because the underlying
+ // read is blocked.
+ go func() {
+ n, err = cr.r.Read(b)
+ close(done)
+ }()
+
+ select {
+ case <-cr.ctx.Done():
+ return 0, cr.ctx.Err()
+ case <-done:
+ return n, err
+ }
+}
diff --git a/src/internal/fuzz/worker_test.go b/src/internal/fuzz/worker_test.go
new file mode 100644
index 0000000..2369b4c
--- /dev/null
+++ b/src/internal/fuzz/worker_test.go
@@ -0,0 +1,147 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzz
+
+import (
+ "context"
+ "flag"
+ "fmt"
+ "io"
+ "os"
+ "os/signal"
+ "reflect"
+ "testing"
+)
+
+var benchmarkWorkerFlag = flag.Bool("benchmarkworker", false, "")
+
+func TestMain(m *testing.M) {
+ flag.Parse()
+ if *benchmarkWorkerFlag {
+ runBenchmarkWorker()
+ return
+ }
+ os.Exit(m.Run())
+}
+
+func BenchmarkWorkerFuzzOverhead(b *testing.B) {
+ origEnv := os.Getenv("GODEBUG")
+ defer func() { os.Setenv("GODEBUG", origEnv) }()
+ os.Setenv("GODEBUG", fmt.Sprintf("%s,fuzzseed=123", origEnv))
+
+ ws := &workerServer{
+ fuzzFn: func(_ CorpusEntry) error { return nil },
+ workerComm: workerComm{memMu: make(chan *sharedMem, 1)},
+ }
+
+ mem, err := sharedMemTempFile(workerSharedMemSize)
+ if err != nil {
+ b.Fatalf("failed to create temporary shared memory file: %s", err)
+ }
+ defer func() {
+ if err := mem.Close(); err != nil {
+ b.Error(err)
+ }
+ }()
+
+ initialVal := []interface{}{make([]byte, 32)}
+ encodedVals := marshalCorpusFile(initialVal...)
+ mem.setValue(encodedVals)
+
+ ws.memMu <- mem
+
+ b.ResetTimer()
+ for i := 0; i < b.N; i++ {
+ ws.m = newMutator()
+ mem.setValue(encodedVals)
+ mem.header().count = 0
+
+ ws.fuzz(context.Background(), fuzzArgs{Limit: 1})
+ }
+}
+
+// BenchmarkWorkerPing acts as the coordinator and measures the time it takes
+// a worker to respond to N pings. This is a rough measure of our RPC latency.
+func BenchmarkWorkerPing(b *testing.B) {
+ b.SetParallelism(1)
+ w := newWorkerForTest(b)
+ for i := 0; i < b.N; i++ {
+ if err := w.client.ping(context.Background()); err != nil {
+ b.Fatal(err)
+ }
+ }
+}
+
+// BenchmarkWorkerFuzz acts as the coordinator and measures the time it takes
+// a worker to mutate a given input and call a trivial fuzz function N times.
+func BenchmarkWorkerFuzz(b *testing.B) {
+ b.SetParallelism(1)
+ w := newWorkerForTest(b)
+ entry := CorpusEntry{Values: []interface{}{[]byte(nil)}}
+ entry.Data = marshalCorpusFile(entry.Values...)
+ for i := int64(0); i < int64(b.N); {
+ args := fuzzArgs{
+ Limit: int64(b.N) - i,
+ Timeout: workerFuzzDuration,
+ }
+ _, resp, err := w.client.fuzz(context.Background(), entry, args)
+ if err != nil {
+ b.Fatal(err)
+ }
+ if resp.Err != "" {
+ b.Fatal(resp.Err)
+ }
+ if resp.Count == 0 {
+ b.Fatal("worker did not make progress")
+ }
+ i += resp.Count
+ }
+}
+
+// newWorkerForTest creates and starts a worker process for testing or
+// benchmarking. The worker process calls RunFuzzWorker, which responds to
+// RPC messages until it's stopped. The process is stopped and cleaned up
+// automatically when the test is done.
+func newWorkerForTest(tb testing.TB) *worker {
+ tb.Helper()
+ c, err := newCoordinator(CoordinateFuzzingOpts{
+ Types: []reflect.Type{reflect.TypeOf([]byte(nil))},
+ Log: io.Discard,
+ })
+ if err != nil {
+ tb.Fatal(err)
+ }
+ dir := "" // same as self
+ binPath := os.Args[0] // same as self
+ args := append(os.Args[1:], "-benchmarkworker")
+ env := os.Environ() // same as self
+ w, err := newWorker(c, dir, binPath, args, env)
+ if err != nil {
+ tb.Fatal(err)
+ }
+ tb.Cleanup(func() {
+ if err := w.cleanup(); err != nil {
+ tb.Error(err)
+ }
+ })
+ if err := w.startAndPing(context.Background()); err != nil {
+ tb.Fatal(err)
+ }
+ tb.Cleanup(func() {
+ if err := w.stop(); err != nil {
+ tb.Error(err)
+ }
+ })
+ return w
+}
+
+func runBenchmarkWorker() {
+ ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
+ defer cancel()
+ fn := func(CorpusEntry) error { return nil }
+ if err := RunFuzzWorker(ctx, fn); err != nil && err != ctx.Err() {
+ panic(err)
+ }
+}
diff --git a/src/testing/benchmark.go b/src/testing/benchmark.go
index 15b4426..30fa106 100644
--- a/src/testing/benchmark.go
+++ b/src/testing/benchmark.go
@@ -32,35 +32,36 @@
matchBenchmarks *string
benchmarkMemory *bool
- benchTime = benchTimeFlag{d: 1 * time.Second} // changed during test of testing package
+ benchTime = durationOrCountFlag{d: 1 * time.Second} // changed during test of testing package
)
-type benchTimeFlag struct {
- d time.Duration
- n int
+type durationOrCountFlag struct {
+ d time.Duration
+ n int
+ allowZero bool
}
-func (f *benchTimeFlag) String() string {
+func (f *durationOrCountFlag) String() string {
if f.n > 0 {
return fmt.Sprintf("%dx", f.n)
}
return time.Duration(f.d).String()
}
-func (f *benchTimeFlag) Set(s string) error {
+func (f *durationOrCountFlag) Set(s string) error {
if strings.HasSuffix(s, "x") {
n, err := strconv.ParseInt(s[:len(s)-1], 10, 0)
- if err != nil || n <= 0 {
+ if err != nil || n < 0 || (!f.allowZero && n == 0) {
return fmt.Errorf("invalid count")
}
- *f = benchTimeFlag{n: int(n)}
+ *f = durationOrCountFlag{n: int(n)}
return nil
}
d, err := time.ParseDuration(s)
- if err != nil || d <= 0 {
+ if err != nil || d < 0 || (!f.allowZero && d == 0) {
return fmt.Errorf("invalid duration")
}
- *f = benchTimeFlag{d: d}
+ *f = durationOrCountFlag{d: d}
return nil
}
@@ -98,7 +99,7 @@
previousN int // number of iterations in the previous run
previousDuration time.Duration // total duration of the previous run
benchFunc func(b *B)
- benchTime benchTimeFlag
+ benchTime durationOrCountFlag
bytes int64
missingBytes bool // one of the subbenchmarks does not have bytes set.
timerOn bool
diff --git a/src/testing/fuzz.go b/src/testing/fuzz.go
new file mode 100644
index 0000000..57ea418
--- /dev/null
+++ b/src/testing/fuzz.go
@@ -0,0 +1,783 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package testing
+
+import (
+ "errors"
+ "flag"
+ "fmt"
+ "io"
+ "os"
+ "path/filepath"
+ "reflect"
+ "runtime"
+ "sync/atomic"
+ "time"
+)
+
+func initFuzzFlags() {
+ matchFuzz = flag.String("test.fuzz", "", "run the fuzz target matching `regexp`")
+ flag.Var(&fuzzDuration, "test.fuzztime", "time to spend fuzzing; default is to run indefinitely")
+ flag.Var(&minimizeDuration, "test.fuzzminimizetime", "time to spend minimizing a value after finding a crash")
+ fuzzCacheDir = flag.String("test.fuzzcachedir", "", "directory where interesting fuzzing inputs are stored")
+ isFuzzWorker = flag.Bool("test.fuzzworker", false, "coordinate with the parent process to fuzz random values")
+}
+
+var (
+ matchFuzz *string
+ fuzzDuration durationOrCountFlag
+ minimizeDuration = durationOrCountFlag{d: 60 * time.Second, allowZero: true}
+ fuzzCacheDir *string
+ isFuzzWorker *bool
+
+ // corpusDir is the parent directory of the target's seed corpus within
+ // the package.
+ corpusDir = "testdata/fuzz"
+)
+
+// fuzzWorkerExitCode is used as an exit code by fuzz worker processes after an internal error.
+// This distinguishes internal errors from uncontrolled panics and other crashes.
+// Keep in sync with internal/fuzz.workerExitCode.
+const fuzzWorkerExitCode = 70
+
+// InternalFuzzTarget is an internal type but exported because it is cross-package;
+// it is part of the implementation of the "go test" command.
+type InternalFuzzTarget struct {
+ Name string
+ Fn func(f *F)
+}
+
+// F is a type passed to fuzz targets.
+//
+// A fuzz target may add seed corpus entries using F.Add or by storing files in
+// the testdata/fuzz/<FuzzTargetName> directory. The fuzz target must then
+// call F.Fuzz once to provide a fuzz function. See the testing package
+// documentation for an example, and see the F.Fuzz and F.Add method
+// documentation for details.
+type F struct {
+ common
+ fuzzContext *fuzzContext
+ testContext *testContext
+
+ // inFuzzFn is true when the fuzz function is running. Most F methods cannot
+ // be called when inFuzzFn is true.
+ inFuzzFn bool
+
+ // corpus is a set of seed corpus entries, added with F.Add and loaded
+ // from testdata.
+ corpus []corpusEntry
+
+ result FuzzResult
+ fuzzCalled bool
+}
+
+var _ TB = (*F)(nil)
+
+// corpusEntry is an alias to the same type as internal/fuzz.CorpusEntry.
+// We use a type alias because we don't want to export this type, and we can't
+// import internal/fuzz from testing.
+type corpusEntry = struct {
+ Parent string
+ Name string
+ Data []byte
+ Values []interface{}
+ Generation int
+ IsSeed bool
+}
+
+// Cleanup registers a function to be called after the fuzz function has been
+// called on all seed corpus entries, and after fuzzing completes (if enabled).
+// Cleanup functions will be called in last added, first called order.
+func (f *F) Cleanup(fn func()) {
+ if f.inFuzzFn {
+ panic("testing: f.Cleanup was called inside the f.Fuzz function, use t.Cleanup instead")
+ }
+ f.common.Helper()
+ f.common.Cleanup(fn)
+}
+
+// Error is equivalent to Log followed by Fail.
+func (f *F) Error(args ...interface{}) {
+ if f.inFuzzFn {
+ panic("testing: f.Error was called inside the f.Fuzz function, use t.Error instead")
+ }
+ f.common.Helper()
+ f.common.Error(args...)
+}
+
+// Errorf is equivalent to Logf followed by Fail.
+func (f *F) Errorf(format string, args ...interface{}) {
+ if f.inFuzzFn {
+ panic("testing: f.Errorf was called inside the f.Fuzz function, use t.Errorf instead")
+ }
+ f.common.Helper()
+ f.common.Errorf(format, args...)
+}
+
+// Fail marks the function as having failed but continues execution.
+func (f *F) Fail() {
+ if f.inFuzzFn {
+ panic("testing: f.Fail was called inside the f.Fuzz function, use t.Fail instead")
+ }
+ f.common.Helper()
+ f.common.Fail()
+}
+
+// FailNow marks the function as having failed and stops its execution
+// by calling runtime.Goexit (which then runs all deferred calls in the
+// current goroutine).
+// Execution will continue at the next test, benchmark, or fuzz function.
+// FailNow must be called from the goroutine running the
+// fuzz target, not from other goroutines
+// created during the test. Calling FailNow does not stop
+// those other goroutines.
+func (f *F) FailNow() {
+ if f.inFuzzFn {
+ panic("testing: f.FailNow was called inside the f.Fuzz function, use t.FailNow instead")
+ }
+ f.common.Helper()
+ f.common.FailNow()
+}
+
+// Fatal is equivalent to Log followed by FailNow.
+func (f *F) Fatal(args ...interface{}) {
+ if f.inFuzzFn {
+ panic("testing: f.Fatal was called inside the f.Fuzz function, use t.Fatal instead")
+ }
+ f.common.Helper()
+ f.common.Fatal(args...)
+}
+
+// Fatalf is equivalent to Logf followed by FailNow.
+func (f *F) Fatalf(format string, args ...interface{}) {
+ if f.inFuzzFn {
+ panic("testing: f.Fatalf was called inside the f.Fuzz function, use t.Fatalf instead")
+ }
+ f.common.Helper()
+ f.common.Fatalf(format, args...)
+}
+
+// Helper marks the calling function as a test helper function.
+// When printing file and line information, that function will be skipped.
+// Helper may be called simultaneously from multiple goroutines.
+func (f *F) Helper() {
+ if f.inFuzzFn {
+ panic("testing: f.Helper was called inside the f.Fuzz function, use t.Helper instead")
+ }
+
+ // common.Helper is inlined here.
+ // If we called it, it would mark F.Helper as the helper
+ // instead of the caller.
+ f.mu.Lock()
+ defer f.mu.Unlock()
+ if f.helperPCs == nil {
+ f.helperPCs = make(map[uintptr]struct{})
+ }
+ // repeating code from callerName here to save walking a stack frame
+ var pc [1]uintptr
+ n := runtime.Callers(2, pc[:]) // skip runtime.Callers + Helper
+ if n == 0 {
+ panic("testing: zero callers found")
+ }
+ if _, found := f.helperPCs[pc[0]]; !found {
+ f.helperPCs[pc[0]] = struct{}{}
+ f.helperNames = nil // map will be recreated next time it is needed
+ }
+}
+
+// Setenv calls os.Setenv(key, value) and uses Cleanup to restore the
+// environment variable to its original value after the test.
+//
+// When fuzzing is enabled, the fuzzing engine spawns worker processes running
+// the test binary. Each worker process inherits the environment of the parent
+// process, including environment variables set with F.Setenv.
+func (f *F) Setenv(key, value string) {
+ if f.inFuzzFn {
+ panic("testing: f.Setenv was called inside the f.Fuzz function, use t.Setenv instead")
+ }
+ f.common.Helper()
+ f.common.Setenv(key, value)
+}
+
+// Skip is equivalent to Log followed by SkipNow.
+func (f *F) Skip(args ...interface{}) {
+ if f.inFuzzFn {
+ panic("testing: f.Skip was called inside the f.Fuzz function, use t.Skip instead")
+ }
+ f.common.Helper()
+ f.common.Skip(args...)
+}
+
+// SkipNow marks the test as having been skipped and stops its execution
+// by calling runtime.Goexit.
+// If a test fails (see Error, Errorf, Fail) and is then skipped,
+// it is still considered to have failed.
+// Execution will continue at the next test or benchmark. See also FailNow.
+// SkipNow must be called from the goroutine running the test, not from
+// other goroutines created during the test. Calling SkipNow does not stop
+// those other goroutines.
+func (f *F) SkipNow() {
+ if f.inFuzzFn {
+ panic("testing: f.SkipNow was called inside the f.Fuzz function, use t.SkipNow instead")
+ }
+ f.common.Helper()
+ f.common.SkipNow()
+}
+
+// Skipf is equivalent to Logf followed by SkipNow.
+func (f *F) Skipf(format string, args ...interface{}) {
+ if f.inFuzzFn {
+ panic("testing: f.Skipf was called inside the f.Fuzz function, use t.Skipf instead")
+ }
+ f.common.Helper()
+ f.common.Skipf(format, args...)
+}
+
+// TempDir returns a temporary directory for the test to use.
+// The directory is automatically removed by Cleanup when the test and
+// all its subtests complete.
+// Each subsequent call to t.TempDir returns a unique directory;
+// if the directory creation fails, TempDir terminates the test by calling Fatal.
+func (f *F) TempDir() string {
+ if f.inFuzzFn {
+ panic("testing: f.TempDir was called inside the f.Fuzz function, use t.TempDir instead")
+ }
+ f.common.Helper()
+ return f.common.TempDir()
+}
+
+// Add will add the arguments to the seed corpus for the fuzz target. This will
+// be a no-op if called after or within the Fuzz function. The args must match
+// those in the Fuzz function.
+func (f *F) Add(args ...interface{}) {
+ var values []interface{}
+ for i := range args {
+ if t := reflect.TypeOf(args[i]); !supportedTypes[t] {
+ panic(fmt.Sprintf("testing: unsupported type to Add %v", t))
+ }
+ values = append(values, args[i])
+ }
+ f.corpus = append(f.corpus, corpusEntry{Values: values, IsSeed: true, Name: fmt.Sprintf("seed#%d", len(f.corpus))})
+}
+
+// supportedTypes represents all of the supported types which can be fuzzed.
+var supportedTypes = map[reflect.Type]bool{
+ reflect.TypeOf(([]byte)("")): true,
+ reflect.TypeOf((string)("")): true,
+ reflect.TypeOf((bool)(false)): true,
+ reflect.TypeOf((byte)(0)): true,
+ reflect.TypeOf((rune)(0)): true,
+ reflect.TypeOf((float32)(0)): true,
+ reflect.TypeOf((float64)(0)): true,
+ reflect.TypeOf((int)(0)): true,
+ reflect.TypeOf((int8)(0)): true,
+ reflect.TypeOf((int16)(0)): true,
+ reflect.TypeOf((int32)(0)): true,
+ reflect.TypeOf((int64)(0)): true,
+ reflect.TypeOf((uint)(0)): true,
+ reflect.TypeOf((uint8)(0)): true,
+ reflect.TypeOf((uint16)(0)): true,
+ reflect.TypeOf((uint32)(0)): true,
+ reflect.TypeOf((uint64)(0)): true,
+}
+
+// Fuzz runs the fuzz function, ff, for fuzz testing. If ff fails for a set of
+// arguments, those arguments will be added to the seed corpus.
+//
+// ff must be a function with no return value whose first argument is *T and
+// whose remaining arguments are the types to be fuzzed.
+// For example:
+//
+// f.Fuzz(func(t *testing.T, b []byte, i int) { ... })
+//
+// This function should be fast, deterministic, and stateless.
+// None of the pointers to any input data should be retained between executions.
+//
+// This is a terminal function which will terminate the currently running fuzz
+// target by calling runtime.Goexit.
+// To run any code after fuzzing stops, use (*F).Cleanup.
+func (f *F) Fuzz(ff interface{}) {
+ if f.fuzzCalled {
+ panic("testing: F.Fuzz called more than once")
+ }
+ f.fuzzCalled = true
+ if f.failed {
+ return
+ }
+ f.Helper()
+
+ // ff should be in the form func(*testing.T, ...interface{})
+ fn := reflect.ValueOf(ff)
+ fnType := fn.Type()
+ if fnType.Kind() != reflect.Func {
+ panic("testing: F.Fuzz must receive a function")
+ }
+ if fnType.NumIn() < 2 || fnType.In(0) != reflect.TypeOf((*T)(nil)) {
+ panic("testing: F.Fuzz function must receive at least two arguments, where the first argument is a *T")
+ }
+
+ // Save the types of the function to compare against the corpus.
+ var types []reflect.Type
+ for i := 1; i < fnType.NumIn(); i++ {
+ t := fnType.In(i)
+ if !supportedTypes[t] {
+ panic(fmt.Sprintf("testing: unsupported type for fuzzing %v", t))
+ }
+ types = append(types, t)
+ }
+
+ // Load the testdata seed corpus. Check types of entries in the testdata
+ // corpus and entries declared with F.Add.
+ //
+ // Don't load the seed corpus if this is a worker process; we won't use it.
+ if f.fuzzContext.mode != fuzzWorker {
+ for _, c := range f.corpus {
+ if err := f.fuzzContext.deps.CheckCorpus(c.Values, types); err != nil {
+ // TODO(#48302): Report the source location of the F.Add call.
+ f.Fatal(err)
+ }
+ }
+
+ // Load seed corpus
+ c, err := f.fuzzContext.deps.ReadCorpus(filepath.Join(corpusDir, f.name), types)
+ if err != nil {
+ f.Fatal(err)
+ }
+ for i := range c {
+ c[i].IsSeed = true // these are all seed corpus values
+ if f.fuzzContext.mode == fuzzCoordinator {
+ // If this is the coordinator process, zero the values, since we don't need
+ // to hold onto them.
+ c[i].Values = nil
+ }
+ }
+
+ f.corpus = append(f.corpus, c...)
+ }
+
+ // run calls fn on a given input, as a subtest with its own T.
+ // run is analogous to T.Run. The test filtering and cleanup works similarly.
+ // fn is called in its own goroutine.
+ run := func(e corpusEntry) error {
+ if e.Values == nil {
+ // Every code path should have already unmarshaled Data into Values.
+ // It's our fault if it didn't.
+ panic(fmt.Sprintf("corpus file %q was not unmarshaled", e.Name))
+ }
+ if shouldFailFast() {
+ return nil
+ }
+ testName := f.common.name
+ if e.Name != "" {
+ testName = fmt.Sprintf("%s/%s", testName, e.Name)
+ }
+
+ // Record the stack trace at the point of this call so that if the subtest
+ // function - which runs in a separate stack - is marked as a helper, we can
+ // continue walking the stack into the parent test.
+ var pc [maxStackLen]uintptr
+ n := runtime.Callers(2, pc[:])
+ t := &T{
+ common: common{
+ barrier: make(chan bool),
+ signal: make(chan bool),
+ name: testName,
+ parent: &f.common,
+ level: f.level + 1,
+ creator: pc[:n],
+ chatty: f.chatty,
+ fuzzing: true,
+ },
+ context: f.testContext,
+ }
+ t.w = indenter{&t.common}
+ if t.chatty != nil {
+ // TODO(#48132): adjust this to work with test2json.
+ t.chatty.Updatef(t.name, "=== RUN %s\n", t.name)
+ }
+ f.inFuzzFn = true
+ go tRunner(t, func(t *T) {
+ args := []reflect.Value{reflect.ValueOf(t)}
+ for _, v := range e.Values {
+ args = append(args, reflect.ValueOf(v))
+ }
+ // Before reseting the current coverage, defer the snapshot so that we
+ // make sure it is called right before the tRunner function exits,
+ // regardless of whether it was executed cleanly, panicked, or if the
+ // fuzzFn called t.Fatal.
+ defer f.fuzzContext.deps.SnapshotCoverage()
+ f.fuzzContext.deps.ResetCoverage()
+ fn.Call(args)
+ })
+ <-t.signal
+ f.inFuzzFn = false
+ if t.Failed() {
+ return errors.New(string(f.output))
+ }
+ return nil
+ }
+
+ switch f.fuzzContext.mode {
+ case fuzzCoordinator:
+ // Fuzzing is enabled, and this is the test process started by 'go test'.
+ // Act as the coordinator process, and coordinate workers to perform the
+ // actual fuzzing.
+ corpusTargetDir := filepath.Join(corpusDir, f.name)
+ cacheTargetDir := filepath.Join(*fuzzCacheDir, f.name)
+ err := f.fuzzContext.deps.CoordinateFuzzing(
+ fuzzDuration.d,
+ int64(fuzzDuration.n),
+ minimizeDuration.d,
+ int64(minimizeDuration.n),
+ *parallel,
+ f.corpus,
+ types,
+ corpusTargetDir,
+ cacheTargetDir)
+ if err != nil {
+ f.result = FuzzResult{Error: err}
+ f.Fail()
+ fmt.Fprintf(f.w, "%v\n", err)
+ if crashErr, ok := err.(fuzzCrashError); ok {
+ crashName := crashErr.CrashName()
+ fmt.Fprintf(f.w, "Crash written to %s\n", filepath.Join(corpusDir, f.name, crashName))
+ fmt.Fprintf(f.w, "To re-run:\ngo test %s -run=%s/%s\n", f.fuzzContext.deps.ImportPath(), f.name, crashName)
+ }
+ }
+ // TODO(jayconrod,katiehockman): Aggregate statistics across workers
+ // and add to FuzzResult (ie. time taken, num iterations)
+
+ case fuzzWorker:
+ // Fuzzing is enabled, and this is a worker process. Follow instructions
+ // from the coordinator.
+ if err := f.fuzzContext.deps.RunFuzzWorker(run); err != nil {
+ // Internal errors are marked with f.Fail; user code may call this too, before F.Fuzz.
+ // The worker will exit with fuzzWorkerExitCode, indicating this is a failure
+ // (and 'go test' should exit non-zero) but a crasher should not be recorded.
+ f.Errorf("communicating with fuzzing coordinator: %v", err)
+ }
+
+ default:
+ // Fuzzing is not enabled, or will be done later. Only run the seed
+ // corpus now.
+ for _, e := range f.corpus {
+ run(e)
+ }
+ }
+
+ // Record that the fuzz function (or coordinateFuzzing or runFuzzWorker)
+ // returned normally. This is used to distinguish runtime.Goexit below
+ // from panic(nil).
+ f.finished = true
+
+ // Terminate the goroutine. F.Fuzz should not return.
+ // We cannot call runtime.Goexit from a deferred function: if there is a
+ // panic, that would replace the panic value with nil.
+ runtime.Goexit()
+}
+
+func (f *F) report() {
+ if *isFuzzWorker || f.parent == nil {
+ return
+ }
+ dstr := fmtDuration(f.duration)
+ format := "--- %s: %s (%s)\n"
+ if f.Failed() {
+ f.flushToParent(f.name, format, "FAIL", f.name, dstr)
+ } else if f.chatty != nil {
+ if f.Skipped() {
+ f.flushToParent(f.name, format, "SKIP", f.name, dstr)
+ } else {
+ f.flushToParent(f.name, format, "PASS", f.name, dstr)
+ }
+ }
+}
+
+// FuzzResult contains the results of a fuzz run.
+type FuzzResult struct {
+ N int // The number of iterations.
+ T time.Duration // The total time taken.
+ Error error // Error is the error from the crash
+}
+
+func (r FuzzResult) String() string {
+ s := ""
+ if r.Error == nil {
+ return s
+ }
+ s = fmt.Sprintf("%s", r.Error.Error())
+ return s
+}
+
+// fuzzCrashError is satisfied by a crash detected within the fuzz function.
+// These errors are written to the seed corpus and can be re-run with 'go test'.
+// Errors within the fuzzing framework (like I/O errors between coordinator
+// and worker processes) don't satisfy this interface.
+type fuzzCrashError interface {
+ error
+ Unwrap() error
+
+ // CrashName returns the name of the subtest that corresponds to the saved
+ // crash input file in the seed corpus. The test can be re-run with
+ // go test $pkg -run=$target/$name where $pkg is the package's import path,
+ // $target is the fuzz target name, and $name is the string returned here.
+ CrashName() string
+}
+
+// fuzzContext holds fields common to all fuzz targets.
+type fuzzContext struct {
+ deps testDeps
+ mode fuzzMode
+}
+
+type fuzzMode uint8
+
+const (
+ seedCorpusOnly fuzzMode = iota
+ fuzzCoordinator
+ fuzzWorker
+)
+
+// runFuzzTargets runs the fuzz targets matching the pattern for -run. This will
+// only run the f.Fuzz function for each seed corpus without using the fuzzing
+// engine to generate or mutate inputs.
+func runFuzzTargets(deps testDeps, fuzzTargets []InternalFuzzTarget, deadline time.Time) (ran, ok bool) {
+ ok = true
+ if len(fuzzTargets) == 0 || *isFuzzWorker {
+ return ran, ok
+ }
+ m := newMatcher(deps.MatchString, *match, "-test.run")
+ tctx := newTestContext(*parallel, m)
+ tctx.deadline = deadline
+ var mFuzz *matcher
+ if *matchFuzz != "" {
+ mFuzz = newMatcher(deps.MatchString, *matchFuzz, "-test.fuzz")
+ }
+ fctx := &fuzzContext{deps: deps, mode: seedCorpusOnly}
+ root := common{w: os.Stdout} // gather output in one place
+ if Verbose() {
+ root.chatty = newChattyPrinter(root.w)
+ }
+ for _, ft := range fuzzTargets {
+ if shouldFailFast() {
+ break
+ }
+ testName, matched, _ := tctx.match.fullName(nil, ft.Name)
+ if !matched {
+ continue
+ }
+ if mFuzz != nil {
+ if _, fuzzMatched, _ := mFuzz.fullName(nil, ft.Name); fuzzMatched {
+ // If this target will be fuzzed, then don't run the seed corpus
+ // right now. That will happen later.
+ continue
+ }
+ }
+ f := &F{
+ common: common{
+ signal: make(chan bool),
+ barrier: make(chan bool),
+ name: testName,
+ parent: &root,
+ level: root.level + 1,
+ chatty: root.chatty,
+ },
+ testContext: tctx,
+ fuzzContext: fctx,
+ }
+ f.w = indenter{&f.common}
+ if f.chatty != nil {
+ // TODO(#48132): adjust this to work with test2json.
+ f.chatty.Updatef(f.name, "=== RUN %s\n", f.name)
+ }
+
+ go fRunner(f, ft.Fn)
+ <-f.signal
+ }
+ return root.ran, !root.Failed()
+}
+
+// runFuzzing runs the fuzz target matching the pattern for -fuzz. Only one such
+// fuzz target must match. This will run the fuzzing engine to generate and
+// mutate new inputs against the f.Fuzz function.
+//
+// If fuzzing is disabled (-test.fuzz is not set), runFuzzing
+// returns immediately.
+func runFuzzing(deps testDeps, fuzzTargets []InternalFuzzTarget) (ok bool) {
+ // TODO(katiehockman,jayconrod): Should we do something special to make sure
+ // we don't print f.Log statements again with runFuzzing, since we already
+ // would have printed them when we ran runFuzzTargets (ie. seed corpus run)?
+ if len(fuzzTargets) == 0 || *matchFuzz == "" {
+ return true
+ }
+ m := newMatcher(deps.MatchString, *matchFuzz, "-test.fuzz")
+ tctx := newTestContext(1, m)
+ fctx := &fuzzContext{
+ deps: deps,
+ }
+ root := common{w: os.Stdout}
+ if *isFuzzWorker {
+ root.w = io.Discard
+ fctx.mode = fuzzWorker
+ } else {
+ fctx.mode = fuzzCoordinator
+ }
+ if Verbose() && !*isFuzzWorker {
+ root.chatty = newChattyPrinter(root.w)
+ }
+ var target *InternalFuzzTarget
+ var targetName string
+ var matched []string
+ for i := range fuzzTargets {
+ name, ok, _ := tctx.match.fullName(nil, fuzzTargets[i].Name)
+ if !ok {
+ continue
+ }
+ matched = append(matched, name)
+ target = &fuzzTargets[i]
+ targetName = name
+ }
+ if len(matched) == 0 {
+ fmt.Fprintln(os.Stderr, "testing: warning: no targets to fuzz")
+ return true
+ }
+ if len(matched) > 1 {
+ fmt.Fprintf(os.Stderr, "testing: will not fuzz, -fuzz matches more than one target: %v\n", matched)
+ return false
+ }
+
+ f := &F{
+ common: common{
+ signal: make(chan bool),
+ barrier: nil, // T.Parallel has no effect when fuzzing.
+ name: targetName,
+ parent: &root,
+ level: root.level + 1,
+ chatty: root.chatty,
+ },
+ fuzzContext: fctx,
+ testContext: tctx,
+ }
+ f.w = indenter{&f.common}
+ if f.chatty != nil {
+ // TODO(#48132): adjust this to work with test2json.
+ f.chatty.Updatef(f.name, "=== FUZZ %s\n", f.name)
+ }
+ go fRunner(f, target.Fn)
+ <-f.signal
+ return !f.failed
+}
+
+// fRunner wraps a call to a fuzz target and ensures that cleanup functions are
+// called and status flags are set. fRunner should be called in its own
+// goroutine. To wait for its completion, receive from f.signal.
+//
+// fRunner is analogous to tRunner, which wraps subtests started with T.Run.
+// Tests and fuzz targets work a little differently, so for now, these functions
+// aren't consolidated. In particular, because there are no F.Run and F.Parallel
+// methods, i.e., no fuzz sub-targets or parallel fuzz targets, a few
+// simplifications are made. We also require that F.Fuzz, F.Skip, or F.Fail is
+// called.
+func fRunner(f *F, fn func(*F)) {
+ // When this goroutine is done, either because runtime.Goexit was called,
+ // a panic started, or fn returned normally, record the duration and send
+ // t.signal, indicating the fuzz target is done.
+ defer func() {
+ // Detect whether the fuzz target panicked or called runtime.Goexit without
+ // calling F.Fuzz, F.Fail, or F.Skip. If it did, panic (possibly replacing a
+ // nil panic value). Nothing should recover after fRunner unwinds, so this
+ // should crash the process and print stack. Unfortunately, recovering here
+ // adds stack frames, but the location of the original panic should still be
+ // clear.
+ if f.Failed() {
+ atomic.AddUint32(&numFailed, 1)
+ }
+ err := recover()
+ f.mu.RLock()
+ ok := f.skipped || f.failed || (f.fuzzCalled && f.finished)
+ f.mu.RUnlock()
+ if err == nil && !ok {
+ err = errNilPanicOrGoexit
+ }
+
+ // Use a deferred call to ensure that we report that the test is
+ // complete even if a cleanup function calls t.FailNow. See issue 41355.
+ didPanic := false
+ defer func() {
+ if didPanic {
+ return
+ }
+ if err != nil {
+ panic(err)
+ }
+ // Only report that the test is complete if it doesn't panic,
+ // as otherwise the test binary can exit before the panic is
+ // reported to the user. See issue 41479.
+ f.signal <- true
+ }()
+
+ // If we recovered a panic or inappropriate runtime.Goexit, fail the test,
+ // flush the output log up to the root, then panic.
+ doPanic := func(err interface{}) {
+ f.Fail()
+ if r := f.runCleanup(recoverAndReturnPanic); r != nil {
+ f.Logf("cleanup panicked with %v", r)
+ }
+ for root := &f.common; root.parent != nil; root = root.parent {
+ root.mu.Lock()
+ root.duration += time.Since(root.start)
+ d := root.duration
+ root.mu.Unlock()
+ root.flushToParent(root.name, "--- FAIL: %s (%s)\n", root.name, fmtDuration(d))
+ }
+ didPanic = true
+ panic(err)
+ }
+ if err != nil {
+ doPanic(err)
+ }
+
+ // No panic or inappropriate Goexit.
+ f.duration += time.Since(f.start)
+
+ if len(f.sub) > 0 {
+ // Unblock inputs that called T.Parallel while running the seed corpus.
+ // T.Parallel has no effect while fuzzing, so this only affects fuzz
+ // targets run as normal tests.
+ close(f.barrier)
+ // Wait for the subtests to complete.
+ for _, sub := range f.sub {
+ <-sub.signal
+ }
+ cleanupStart := time.Now()
+ err := f.runCleanup(recoverAndReturnPanic)
+ f.duration += time.Since(cleanupStart)
+ if err != nil {
+ doPanic(err)
+ }
+ }
+
+ // Report after all subtests have finished.
+ f.report()
+ f.done = true
+ f.setRan()
+ }()
+ defer func() {
+ if len(f.sub) == 0 {
+ f.runCleanup(normalPanic)
+ }
+ }()
+
+ f.start = time.Now()
+ fn(f)
+
+ // Code beyond this point is only executed if fn returned normally.
+ // That means fn did not call F.Fuzz or F.Skip. It should have called F.Fail.
+ f.mu.Lock()
+ defer f.mu.Unlock()
+ if !f.failed {
+ panic(f.name + " returned without calling F.Fuzz, F.Fail, or F.Skip")
+ }
+}
diff --git a/src/testing/internal/testdeps/deps.go b/src/testing/internal/testdeps/deps.go
index 3608d33..c612355 100644
--- a/src/testing/internal/testdeps/deps.go
+++ b/src/testing/internal/testdeps/deps.go
@@ -12,12 +12,18 @@
import (
"bufio"
+ "context"
+ "internal/fuzz"
"internal/testlog"
"io"
+ "os"
+ "os/signal"
+ "reflect"
"regexp"
"runtime/pprof"
"strings"
"sync"
+ "time"
)
// TestDeps is an implementation of the testing.testDeps interface,
@@ -126,3 +132,68 @@
func (TestDeps) SetPanicOnExit0(v bool) {
testlog.SetPanicOnExit0(v)
}
+
+func (TestDeps) CoordinateFuzzing(
+ timeout time.Duration,
+ limit int64,
+ minimizeTimeout time.Duration,
+ minimizeLimit int64,
+ parallel int,
+ seed []fuzz.CorpusEntry,
+ types []reflect.Type,
+ corpusDir,
+ cacheDir string) (err error) {
+ // Fuzzing may be interrupted with a timeout or if the user presses ^C.
+ // In either case, we'll stop worker processes gracefully and save
+ // crashers and interesting values.
+ ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
+ defer cancel()
+ err = fuzz.CoordinateFuzzing(ctx, fuzz.CoordinateFuzzingOpts{
+ Log: os.Stderr,
+ Timeout: timeout,
+ Limit: limit,
+ MinimizeTimeout: minimizeTimeout,
+ MinimizeLimit: minimizeLimit,
+ Parallel: parallel,
+ Seed: seed,
+ Types: types,
+ CorpusDir: corpusDir,
+ CacheDir: cacheDir,
+ })
+ if err == ctx.Err() {
+ return nil
+ }
+ return err
+}
+
+func (TestDeps) RunFuzzWorker(fn func(fuzz.CorpusEntry) error) error {
+ // Worker processes may or may not receive a signal when the user presses ^C
+ // On POSIX operating systems, a signal sent to a process group is delivered
+ // to all processes in that group. This is not the case on Windows.
+ // If the worker is interrupted, return quickly and without error.
+ // If only the coordinator process is interrupted, it tells each worker
+ // process to stop by closing its "fuzz_in" pipe.
+ ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
+ defer cancel()
+ err := fuzz.RunFuzzWorker(ctx, fn)
+ if err == ctx.Err() {
+ return nil
+ }
+ return err
+}
+
+func (TestDeps) ReadCorpus(dir string, types []reflect.Type) ([]fuzz.CorpusEntry, error) {
+ return fuzz.ReadCorpus(dir, types)
+}
+
+func (TestDeps) CheckCorpus(vals []interface{}, types []reflect.Type) error {
+ return fuzz.CheckCorpus(vals, types)
+}
+
+func (TestDeps) ResetCoverage() {
+ fuzz.ResetCoverage()
+}
+
+func (TestDeps) SnapshotCoverage() {
+ fuzz.SnapshotCoverage()
+}
diff --git a/src/testing/sub_test.go b/src/testing/sub_test.go
index 6c7d83a..6a5add6 100644
--- a/src/testing/sub_test.go
+++ b/src/testing/sub_test.go
@@ -480,9 +480,10 @@
buf := &bytes.Buffer{}
root := &T{
common: common{
- signal: make(chan bool),
- name: "Test",
- w: buf,
+ signal: make(chan bool),
+ barrier: make(chan bool),
+ name: "Test",
+ w: buf,
},
context: ctx,
}
@@ -669,7 +670,7 @@
w: buf,
},
benchFunc: func(b *B) { ok = b.Run("test", tc.f) }, // Use Run to catch failure.
- benchTime: benchTimeFlag{d: 1 * time.Microsecond},
+ benchTime: durationOrCountFlag{d: 1 * time.Microsecond},
}
if tc.chatty {
root.chatty = newChattyPrinter(root.w)
diff --git a/src/testing/testing.go b/src/testing/testing.go
index 2239e01..567eb0d 100644
--- a/src/testing/testing.go
+++ b/src/testing/testing.go
@@ -34,7 +34,7 @@
// its -bench flag is provided. Benchmarks are run sequentially.
//
// For a description of the testing flags, see
-// https://golang.org/cmd/go/#hdr-Testing_flags
+// https://golang.org/cmd/go/#hdr-Testing_flags.
//
// A sample benchmark function looks like this:
// func BenchmarkRandInt(b *testing.B) {
@@ -132,6 +132,30 @@
// example function, at least one other function, type, variable, or constant
// declaration, and no test or benchmark functions.
//
+// Fuzzing
+//
+// Functions of the form
+// func FuzzXxx(*testing.F)
+// are considered fuzz targets, and are executed by the "go test" command. When
+// the -fuzz flag is provided, the functions will be fuzzed.
+//
+// For a description of the testing flags, see
+// https://golang.org/cmd/go/#hdr-Testing_flags.
+//
+// For a description of fuzzing, see golang.org/s/draft-fuzzing-design.
+// TODO(#48255): write and link to documentation that will be helpful to users
+// who are unfamiliar with fuzzing.
+//
+// A sample fuzz target looks like this:
+//
+// func FuzzBytesCmp(f *testing.F) {
+// f.Fuzz(func(t *testing.T, a, b []byte) {
+// if bytes.HasPrefix(a, b) && !bytes.Contains(a, b) {
+// t.Error("HasPrefix is true, but Contains is false")
+// }
+// })
+// }
+//
// Skipping
//
// Tests or benchmarks may be skipped at run time with a call to
@@ -144,6 +168,21 @@
// ...
// }
//
+// The Skip method of *T can be used in a fuzz target if the input is invalid,
+// but should not be considered a crash. For example:
+//
+// func FuzzJSONMarshalling(f *testing.F) {
+// f.Fuzz(func(t *testing.T, b []byte) {
+// var v interface{}
+// if err := json.Unmarshal(b, &v); err != nil {
+// t.Skip()
+// }
+// if _, err := json.Marshal(v); err != nil {
+// t.Error("Marshal: %v", err)
+// }
+// })
+// }
+//
// Subtests and Sub-benchmarks
//
// The Run methods of T and B allow defining subtests and sub-benchmarks,
@@ -163,17 +202,25 @@
// of the top-level test and the sequence of names passed to Run, separated by
// slashes, with an optional trailing sequence number for disambiguation.
//
-// The argument to the -run and -bench command-line flags is an unanchored regular
+// The argument to the -run, -bench, and -fuzz command-line flags is an unanchored regular
// expression that matches the test's name. For tests with multiple slash-separated
// elements, such as subtests, the argument is itself slash-separated, with
// expressions matching each name element in turn. Because it is unanchored, an
// empty expression matches any string.
// For example, using "matching" to mean "whose name contains":
//
-// go test -run '' # Run all tests.
-// go test -run Foo # Run top-level tests matching "Foo", such as "TestFooBar".
-// go test -run Foo/A= # For top-level tests matching "Foo", run subtests matching "A=".
-// go test -run /A=1 # For all top-level tests, run subtests matching "A=1".
+// go test -run '' # Run all tests.
+// go test -run Foo # Run top-level tests matching "Foo", such as "TestFooBar".
+// go test -run Foo/A= # For top-level tests matching "Foo", run subtests matching "A=".
+// go test -run /A=1 # For all top-level tests, run subtests matching "A=1".
+// go test -fuzz FuzzFoo # Fuzz the target matching "FuzzFoo"
+//
+// The -run argument can also be used to run a specific value in the seed
+// corpus, for debugging. For example:
+// go test -run=FuzzFoo/9ddb952d9814
+//
+// The -fuzz and -run flags can both be set, in order to fuzz a target but
+// skip the execution of all other tests.
//
// Subtests can also be used to control parallelism. A parent test will only
// complete once all of its subtests complete. In this example, all tests are
@@ -246,6 +293,7 @@
"io"
"math/rand"
"os"
+ "reflect"
"runtime"
"runtime/debug"
"runtime/trace"
@@ -307,6 +355,7 @@
shuffle = flag.String("test.shuffle", "off", "randomize the execution order of tests and benchmarks")
initBenchmarkFlags()
+ initFuzzFlags()
}
var (
@@ -406,6 +455,7 @@
chatty *chattyPrinter // A copy of chattyPrinter, if the chatty flag is set.
bench bool // Whether the current test is a benchmark.
+ fuzzing bool // Whether the current test is a fuzzing target.
hasSub int32 // Written atomically.
raceErrors int // Number of races detected during test.
runner string // Function name of tRunner running the test.
@@ -538,6 +588,13 @@
// and inserts the final newline if needed and indentation spaces for formatting.
// This function must be called with c.mu held.
func (c *common) decorate(s string, skip int) string {
+ if c.helperNames == nil {
+ c.helperNames = make(map[string]struct{})
+ for pc := range c.helperPCs {
+ c.helperNames[pcToName(pc)] = struct{}{}
+ }
+ }
+
frame := c.frameSkip(skip)
file := frame.File
line := frame.Line
@@ -607,6 +664,17 @@
}
}
+// isFuzzing returns whether the current context, or any of the parent contexts,
+// are a fuzzing target
+func (c *common) isFuzzing() bool {
+ for com := c; com != nil; com = com.parent {
+ if com.fuzzing {
+ return true
+ }
+ }
+ return false
+}
+
type indenter struct {
c *common
}
@@ -1083,6 +1151,12 @@
panic("testing: t.Parallel called after t.Setenv; cannot set environment variables in parallel tests")
}
t.isParallel = true
+ if t.parent.barrier == nil {
+ // T.Parallel has no effect when fuzzing.
+ // Multiple processes may run in parallel, but only one input can run at a
+ // time per process so we can attribute crashes to specific inputs.
+ return
+ }
// We don't want to include the time we spend waiting for serial tests
// in the test duration. Record the elapsed time thus far and reset the
@@ -1155,10 +1229,25 @@
t.Errorf("race detected during execution of test")
}
- // If the test panicked, print any test output before dying.
+ // Check if the test panicked or Goexited inappropriately.
+ //
+ // If this happens in a normal test, print output but continue panicking.
+ // tRunner is called in its own goroutine, so this terminates the process.
+ //
+ // If this happens while fuzzing, recover from the panic and treat it like a
+ // normal failure. It's important that the process keeps running in order to
+ // find short inputs that cause panics.
err := recover()
signal := true
+ if err != nil && t.isFuzzing() {
+ t.Errorf("panic: %s\n%s\n", err, string(debug.Stack()))
+ t.mu.Lock()
+ t.finished = true
+ t.mu.Unlock()
+ err = nil
+ }
+
t.mu.RLock()
finished := t.finished
t.mu.RUnlock()
@@ -1176,6 +1265,7 @@
}
}
}
+
// Use a deferred call to ensure that we report that the test is
// complete even if a cleanup function calls t.FailNow. See issue 41355.
didPanic := false
@@ -1245,7 +1335,7 @@
t.report() // Report after all subtests have finished.
// Do not lock t.done to allow race detector to detect race in case
- // the user does not appropriately synchronizes a goroutine.
+ // the user does not appropriately synchronize a goroutine.
t.done = true
if t.parent != nil && atomic.LoadInt32(&t.hasSub) == 0 {
t.setRan()
@@ -1393,6 +1483,16 @@
func (f matchStringOnly) StartTestLog(io.Writer) {}
func (f matchStringOnly) StopTestLog() error { return errMain }
func (f matchStringOnly) SetPanicOnExit0(bool) {}
+func (f matchStringOnly) CoordinateFuzzing(time.Duration, int64, time.Duration, int64, int, []corpusEntry, []reflect.Type, string, string) error {
+ return errMain
+}
+func (f matchStringOnly) RunFuzzWorker(func(corpusEntry) error) error { return errMain }
+func (f matchStringOnly) ReadCorpus(string, []reflect.Type) ([]corpusEntry, error) {
+ return nil, errMain
+}
+func (f matchStringOnly) CheckCorpus([]interface{}, []reflect.Type) error { return nil }
+func (f matchStringOnly) ResetCoverage() {}
+func (f matchStringOnly) SnapshotCoverage() {}
// Main is an internal function, part of the implementation of the "go test" command.
// It was exported because it is cross-package and predates "internal" packages.
@@ -1401,15 +1501,16 @@
// new functionality is added to the testing package.
// Systems simulating "go test" should be updated to use MainStart.
func Main(matchString func(pat, str string) (bool, error), tests []InternalTest, benchmarks []InternalBenchmark, examples []InternalExample) {
- os.Exit(MainStart(matchStringOnly(matchString), tests, benchmarks, examples).Run())
+ os.Exit(MainStart(matchStringOnly(matchString), tests, benchmarks, nil, examples).Run())
}
// M is a type passed to a TestMain function to run the actual tests.
type M struct {
- deps testDeps
- tests []InternalTest
- benchmarks []InternalBenchmark
- examples []InternalExample
+ deps testDeps
+ tests []InternalTest
+ benchmarks []InternalBenchmark
+ fuzzTargets []InternalFuzzTarget
+ examples []InternalExample
timer *time.Timer
afterOnce sync.Once
@@ -1434,18 +1535,25 @@
StartTestLog(io.Writer)
StopTestLog() error
WriteProfileTo(string, io.Writer, int) error
+ CoordinateFuzzing(time.Duration, int64, time.Duration, int64, int, []corpusEntry, []reflect.Type, string, string) error
+ RunFuzzWorker(func(corpusEntry) error) error
+ ReadCorpus(string, []reflect.Type) ([]corpusEntry, error)
+ CheckCorpus([]interface{}, []reflect.Type) error
+ ResetCoverage()
+ SnapshotCoverage()
}
// MainStart is meant for use by tests generated by 'go test'.
// It is not meant to be called directly and is not subject to the Go 1 compatibility document.
// It may change signature from release to release.
-func MainStart(deps testDeps, tests []InternalTest, benchmarks []InternalBenchmark, examples []InternalExample) *M {
+func MainStart(deps testDeps, tests []InternalTest, benchmarks []InternalBenchmark, fuzzTargets []InternalFuzzTarget, examples []InternalExample) *M {
Init()
return &M{
- deps: deps,
- tests: tests,
- benchmarks: benchmarks,
- examples: examples,
+ deps: deps,
+ tests: tests,
+ benchmarks: benchmarks,
+ fuzzTargets: fuzzTargets,
+ examples: examples,
}
}
@@ -1472,9 +1580,15 @@
m.exitCode = 2
return
}
+ if *matchFuzz != "" && *fuzzCacheDir == "" {
+ fmt.Fprintln(os.Stderr, "testing: -test.fuzzcachedir must be set if -test.fuzz is set")
+ flag.Usage()
+ m.exitCode = 2
+ return
+ }
if len(*matchList) != 0 {
- listTests(m.deps.MatchString, m.tests, m.benchmarks, m.examples)
+ listTests(m.deps.MatchString, m.tests, m.benchmarks, m.fuzzTargets, m.examples)
m.exitCode = 0
return
}
@@ -1502,22 +1616,42 @@
m.before()
defer m.after()
- deadline := m.startAlarm()
- haveExamples = len(m.examples) > 0
- testRan, testOk := runTests(m.deps.MatchString, m.tests, deadline)
- exampleRan, exampleOk := runExamples(m.deps.MatchString, m.examples)
- m.stopAlarm()
- if !testRan && !exampleRan && *matchBenchmarks == "" {
- fmt.Fprintln(os.Stderr, "testing: warning: no tests to run")
+
+ // Run tests, examples, and benchmarks unless this is a fuzz worker process.
+ // Workers start after this is done by their parent process, and they should
+ // not repeat this work.
+ if !*isFuzzWorker {
+ deadline := m.startAlarm()
+ haveExamples = len(m.examples) > 0
+ testRan, testOk := runTests(m.deps.MatchString, m.tests, deadline)
+ fuzzTargetsRan, fuzzTargetsOk := runFuzzTargets(m.deps, m.fuzzTargets, deadline)
+ exampleRan, exampleOk := runExamples(m.deps.MatchString, m.examples)
+ m.stopAlarm()
+ if !testRan && !exampleRan && !fuzzTargetsRan && *matchBenchmarks == "" && *matchFuzz == "" {
+ fmt.Fprintln(os.Stderr, "testing: warning: no tests to run")
+ }
+ if !testOk || !exampleOk || !fuzzTargetsOk || !runBenchmarks(m.deps.ImportPath(), m.deps.MatchString, m.benchmarks) || race.Errors() > 0 {
+ fmt.Println("FAIL")
+ m.exitCode = 1
+ return
+ }
}
- if !testOk || !exampleOk || !runBenchmarks(m.deps.ImportPath(), m.deps.MatchString, m.benchmarks) || race.Errors() > 0 {
+
+ fuzzingOk := runFuzzing(m.deps, m.fuzzTargets)
+ if !fuzzingOk {
fmt.Println("FAIL")
- m.exitCode = 1
+ if *isFuzzWorker {
+ m.exitCode = fuzzWorkerExitCode
+ } else {
+ m.exitCode = 1
+ }
return
}
- fmt.Println("PASS")
m.exitCode = 0
+ if !*isFuzzWorker {
+ fmt.Println("PASS")
+ }
return
}
@@ -1538,7 +1672,7 @@
}
}
-func listTests(matchString func(pat, str string) (bool, error), tests []InternalTest, benchmarks []InternalBenchmark, examples []InternalExample) {
+func listTests(matchString func(pat, str string) (bool, error), tests []InternalTest, benchmarks []InternalBenchmark, fuzzTargets []InternalFuzzTarget, examples []InternalExample) {
if _, err := matchString(*matchList, "non-empty"); err != nil {
fmt.Fprintf(os.Stderr, "testing: invalid regexp in -test.list (%q): %s\n", *matchList, err)
os.Exit(1)
@@ -1554,6 +1688,11 @@
fmt.Println(bench.Name)
}
}
+ for _, fuzzTarget := range fuzzTargets {
+ if ok, _ := matchString(*matchList, fuzzTarget.Name); ok {
+ fmt.Println(fuzzTarget.Name)
+ }
+ }
for _, example := range examples {
if ok, _ := matchString(*matchList, example.Name); ok {
fmt.Println(example.Name)
