blob: 8b7a42305e3fa1e96eadc7e3d31907783c94531c [file] [log] [blame]
// Copyright 2018 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 debug
import (
"fmt"
"runtime"
"strconv"
"strings"
)
// exported from runtime.
func modinfo() string
// ReadBuildInfo returns the build information embedded
// in the running binary. The information is available only
// in binaries built with module support.
func ReadBuildInfo() (info *BuildInfo, ok bool) {
data := modinfo()
if len(data) < 32 {
return nil, false
}
data = data[16 : len(data)-16]
bi, err := ParseBuildInfo(data)
if err != nil {
return nil, false
}
// The go version is stored separately from other build info, mostly for
// historical reasons. It is not part of the modinfo() string, and
// ParseBuildInfo does not recognize it. We inject it here to hide this
// awkwardness from the user.
bi.GoVersion = runtime.Version()
return bi, true
}
// BuildInfo represents the build information read from a Go binary.
type BuildInfo struct {
// GoVersion is the version of the Go toolchain that built the binary
// (for example, "go1.19.2").
GoVersion string
// Path is the package path of the main package for the binary
// (for example, "golang.org/x/tools/cmd/stringer").
Path string
// Main describes the module that contains the main package for the binary.
Main Module
// Deps describes all the dependency modules, both direct and indirect,
// that contributed packages to the build of this binary.
Deps []*Module
// Settings describes the build settings used to build the binary.
Settings []BuildSetting
}
// A Module describes a single module included in a build.
type Module struct {
Path string // module path
Version string // module version
Sum string // checksum
Replace *Module // replaced by this module
}
// A BuildSetting is a key-value pair describing one setting that influenced a build.
//
// Defined keys include:
//
// - -buildmode: the buildmode flag used (typically "exe")
// - -compiler: the compiler toolchain flag used (typically "gc")
// - CGO_ENABLED: the effective CGO_ENABLED environment variable
// - CGO_CFLAGS: the effective CGO_CFLAGS environment variable
// - CGO_CPPFLAGS: the effective CGO_CPPFLAGS environment variable
// - CGO_CXXFLAGS: the effective CGO_CPPFLAGS environment variable
// - CGO_LDFLAGS: the effective CGO_CPPFLAGS environment variable
// - GOARCH: the architecture target
// - GOAMD64/GOARM64/GO386/etc: the architecture feature level for GOARCH
// - GOOS: the operating system target
// - vcs: the version control system for the source tree where the build ran
// - vcs.revision: the revision identifier for the current commit or checkout
// - vcs.time: the modification time associated with vcs.revision, in RFC3339 format
// - vcs.modified: true or false indicating whether the source tree had local modifications
type BuildSetting struct {
// Key and Value describe the build setting.
// Key must not contain an equals sign, space, tab, or newline.
// Value must not contain newlines ('\n').
Key, Value string
}
// quoteKey reports whether key is required to be quoted.
func quoteKey(key string) bool {
return len(key) == 0 || strings.ContainsAny(key, "= \t\r\n\"`")
}
// quoteValue reports whether value is required to be quoted.
func quoteValue(value string) bool {
return strings.ContainsAny(value, " \t\r\n\"`")
}
func (bi *BuildInfo) String() string {
buf := new(strings.Builder)
if bi.GoVersion != "" {
fmt.Fprintf(buf, "go\t%s\n", bi.GoVersion)
}
if bi.Path != "" {
fmt.Fprintf(buf, "path\t%s\n", bi.Path)
}
var formatMod func(string, Module)
formatMod = func(word string, m Module) {
buf.WriteString(word)
buf.WriteByte('\t')
buf.WriteString(m.Path)
buf.WriteByte('\t')
buf.WriteString(m.Version)
if m.Replace == nil {
buf.WriteByte('\t')
buf.WriteString(m.Sum)
} else {
buf.WriteByte('\n')
formatMod("=>", *m.Replace)
}
buf.WriteByte('\n')
}
if bi.Main != (Module{}) {
formatMod("mod", bi.Main)
}
for _, dep := range bi.Deps {
formatMod("dep", *dep)
}
for _, s := range bi.Settings {
key := s.Key
if quoteKey(key) {
key = strconv.Quote(key)
}
value := s.Value
if quoteValue(value) {
value = strconv.Quote(value)
}
fmt.Fprintf(buf, "build\t%s=%s\n", key, value)
}
return buf.String()
}
func ParseBuildInfo(data string) (bi *BuildInfo, err error) {
lineNum := 1
defer func() {
if err != nil {
err = fmt.Errorf("could not parse Go build info: line %d: %w", lineNum, err)
}
}()
var (
pathLine = "path\t"
modLine = "mod\t"
depLine = "dep\t"
repLine = "=>\t"
buildLine = "build\t"
newline = "\n"
tab = "\t"
)
readModuleLine := func(elem []string) (Module, error) {
if len(elem) != 2 && len(elem) != 3 {
return Module{}, fmt.Errorf("expected 2 or 3 columns; got %d", len(elem))
}
version := elem[1]
sum := ""
if len(elem) == 3 {
sum = elem[2]
}
return Module{
Path: elem[0],
Version: version,
Sum: sum,
}, nil
}
bi = new(BuildInfo)
var (
last *Module
line string
ok bool
)
// Reverse of BuildInfo.String(), except for go version.
for len(data) > 0 {
line, data, ok = strings.Cut(data, newline)
if !ok {
break
}
switch {
case strings.HasPrefix(line, pathLine):
elem := line[len(pathLine):]
bi.Path = string(elem)
case strings.HasPrefix(line, modLine):
elem := strings.Split(line[len(modLine):], tab)
last = &bi.Main
*last, err = readModuleLine(elem)
if err != nil {
return nil, err
}
case strings.HasPrefix(line, depLine):
elem := strings.Split(line[len(depLine):], tab)
last = new(Module)
bi.Deps = append(bi.Deps, last)
*last, err = readModuleLine(elem)
if err != nil {
return nil, err
}
case strings.HasPrefix(line, repLine):
elem := strings.Split(line[len(repLine):], tab)
if len(elem) != 3 {
return nil, fmt.Errorf("expected 3 columns for replacement; got %d", len(elem))
}
if last == nil {
return nil, fmt.Errorf("replacement with no module on previous line")
}
last.Replace = &Module{
Path: string(elem[0]),
Version: string(elem[1]),
Sum: string(elem[2]),
}
last = nil
case strings.HasPrefix(line, buildLine):
kv := line[len(buildLine):]
if len(kv) < 1 {
return nil, fmt.Errorf("build line missing '='")
}
var key, rawValue string
switch kv[0] {
case '=':
return nil, fmt.Errorf("build line with missing key")
case '`', '"':
rawKey, err := strconv.QuotedPrefix(kv)
if err != nil {
return nil, fmt.Errorf("invalid quoted key in build line")
}
if len(kv) == len(rawKey) {
return nil, fmt.Errorf("build line missing '=' after quoted key")
}
if c := kv[len(rawKey)]; c != '=' {
return nil, fmt.Errorf("unexpected character after quoted key: %q", c)
}
key, _ = strconv.Unquote(rawKey)
rawValue = kv[len(rawKey)+1:]
default:
var ok bool
key, rawValue, ok = strings.Cut(kv, "=")
if !ok {
return nil, fmt.Errorf("build line missing '=' after key")
}
if quoteKey(key) {
return nil, fmt.Errorf("unquoted key %q must be quoted", key)
}
}
var value string
if len(rawValue) > 0 {
switch rawValue[0] {
case '`', '"':
var err error
value, err = strconv.Unquote(rawValue)
if err != nil {
return nil, fmt.Errorf("invalid quoted value in build line")
}
default:
value = rawValue
if quoteValue(value) {
return nil, fmt.Errorf("unquoted value %q must be quoted", value)
}
}
}
bi.Settings = append(bi.Settings, BuildSetting{Key: key, Value: value})
}
lineNum++
}
return bi, nil
}