go/gccgoexportdata: correctly handle archive files containing string tables
If the name of an archive member is longer than 16 bytes, an ELF archive
file contains a string table of file names under the name "//", and this
member has no mode. Skip such members.
+ Test.
Change-Id: Ib10db1cc42816c9002433be6176240e490678560
Reviewed-on: https://go-review.googlesource.com/32973
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/go/gccgoexportdata/gccgoexportdata.go b/go/gccgoexportdata/gccgoexportdata.go
index ca5f75f..30ed521 100644
--- a/go/gccgoexportdata/gccgoexportdata.go
+++ b/go/gccgoexportdata/gccgoexportdata.go
@@ -74,17 +74,14 @@
return sec.Open(), nil
}
-// firstSection returns the contents of the first non-empty section of the archive file.
+// firstSection returns the contents of the first regular file in an ELF
+// archive (http://www.sco.com/developers/devspecs/gabi41.pdf, §7.2).
func firstSection(a []byte) ([]byte, error) {
for len(a) >= 60 {
var hdr []byte
hdr, a = a[:60], a[60:]
- modeStr := string(string(hdr[40:48]))
- mode, err := strconv.Atoi(strings.TrimSpace(modeStr))
- if err != nil {
- return nil, fmt.Errorf("invalid mode: %q", modeStr)
- }
+ name := strings.TrimSpace(string(hdr[:16]))
sizeStr := string(hdr[48:58])
size, err := strconv.Atoi(strings.TrimSpace(sizeStr))
@@ -92,16 +89,25 @@
return nil, fmt.Errorf("invalid size: %q", sizeStr)
}
- var payload []byte
- payload, a = a[:size], a[size:]
+ if len(a) < size {
+ return nil, fmt.Errorf("invalid section size: %d", size)
+ }
- if mode == 0 {
- continue // skip "/"
+ // The payload is padded to an even number of bytes.
+ var payload []byte
+ payload, a = a[:size], a[size+size&1:]
+
+ // Skip special files:
+ // "/" archive symbol table
+ // "/SYM64/" archive symbol table on e.g. s390x
+ // "//" archive string table (if any filename is >15 bytes)
+ if name == "/" || name == "/SYM64/" || name == "//" {
+ continue
}
return payload, nil
}
- return nil, fmt.Errorf("archive has no non-empty sections")
+ return nil, fmt.Errorf("archive has no regular sections")
}
// Read reads export data from in, decodes it, and returns type
diff --git a/go/gccgoexportdata/gccgoexportdata_test.go b/go/gccgoexportdata/gccgoexportdata_test.go
index 131f413..1aa114c 100644
--- a/go/gccgoexportdata/gccgoexportdata_test.go
+++ b/go/gccgoexportdata/gccgoexportdata_test.go
@@ -9,28 +9,59 @@
)
// Test ensures this package can read gccgo export data from the
-// .go_export section of an ELF file.
+// .go_export from a standalone ELF file or such a file in an archive
+// library.
+//
+// The testdata/{short,long}.a ELF archive files were produced by:
+//
+// $ echo 'package foo; func F()' > foo.go
+// $ gccgo -c -fgo-pkgpath blah foo.go
+// $ objcopy -j .go_export foo.o foo.gox
+// $ ar q short.a foo.gox
+// $ objcopy -j .go_export foo.o name-longer-than-16-bytes.gox
+// $ ar q long.a name-longer-than-16-bytes.gox
+//
+// The file long.a contains an archive string table.
+//
+// The errors.gox file (an ELF object file) comes from the toolchain's
+// standard library.
func Test(t *testing.T) {
- f, err := os.Open("testdata/errors.gox")
- if err != nil {
- t.Fatal(err)
- }
- defer f.Close()
- r, err := gccgoexportdata.NewReader(f)
- if err != nil {
- t.Fatal(err)
- }
- imports := make(map[string]*types.Package)
- pkg, err := gccgoexportdata.Read(r, nil, imports, "errors")
- if err != nil {
+ for _, test := range []struct {
+ filename, path, member, wantType string
+ }{
+ {"testdata/errors.gox", "errors", "New", "func(text string) error"},
+ {"testdata/short.a", "short", "F", "func()"},
+ {"testdata/long.a", "long", "F", "func()"},
+ } {
+ t.Logf("filename = %s", test.filename)
+ f, err := os.Open(test.filename)
+ if err != nil {
+ t.Error(err)
+ continue
+ }
+ defer f.Close()
+ r, err := gccgoexportdata.NewReader(f)
+ if err != nil {
+ t.Error(err)
+ continue
+ }
- t.Fatal(err)
- }
+ imports := make(map[string]*types.Package)
+ pkg, err := gccgoexportdata.Read(r, nil, imports, test.path)
+ if err != nil {
+ t.Error(err)
+ continue
+ }
- // Check type of errors.New.
- got := pkg.Scope().Lookup("New").Type().String()
- want := "func(text string) error"
- if got != want {
- t.Errorf("New.Type = %s, want %s", got, want)
+ // Check type of designated package member.
+ obj := pkg.Scope().Lookup(test.member)
+ if obj == nil {
+ t.Errorf("%s.%s not found", test.path, test.member)
+ continue
+ }
+ if obj.Type().String() != test.wantType {
+ t.Errorf("%s.%s.Type = %s, want %s",
+ test.path, test.member, obj.Type(), test.wantType)
+ }
}
}
diff --git a/go/gccgoexportdata/testdata/long.a b/go/gccgoexportdata/testdata/long.a
new file mode 100644
index 0000000..c150447
--- /dev/null
+++ b/go/gccgoexportdata/testdata/long.a
Binary files differ
diff --git a/go/gccgoexportdata/testdata/short.a b/go/gccgoexportdata/testdata/short.a
new file mode 100644
index 0000000..3cd756e
--- /dev/null
+++ b/go/gccgoexportdata/testdata/short.a
Binary files differ
