1 files changed, 168 insertions, 0 deletions
diff --git a/src/cmd/go/internal/version/version.go b/src/cmd/go/internal/version/version.go
new file mode 100644
index 0000000..a0f6123
--- /dev/null
+++ b/src/cmd/go/internal/version/version.go
@@ -0,0 +1,168 @@
+// Copyright 2011 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 version implements the “go version” command.
+package version
+
+import (
+	"context"
+	"debug/buildinfo"
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+
+	"cmd/go/internal/base"
+)
+
+var CmdVersion = &base.Command{
+	UsageLine: "go version [-m] [-v] [file ...]",
+	Short:     "print Go version",
+	Long: `Version prints the build information for Go binary files.
+
+Go version reports the Go version used to build each of the named files.
+
+If no files are named on the command line, go version prints its own
+version information.
+
+If a directory is named, go version walks that directory, recursively,
+looking for recognized Go binaries and reporting their versions.
+By default, go version does not report unrecognized files found
+during a directory scan. The -v flag causes it to report unrecognized files.
+
+The -m flag causes go version to print each file's embedded
+module version information, when available. In the output, the module
+information consists of multiple lines following the version line, each
+indented by a leading tab character.
+
+See also: go doc runtime/debug.BuildInfo.
+`,
+}
+
+func init() {
+	base.AddChdirFlag(&CmdVersion.Flag)
+	CmdVersion.Run = runVersion // break init cycle
+}
+
+var (
+	versionM = CmdVersion.Flag.Bool("m", false, "")
+	versionV = CmdVersion.Flag.Bool("v", false, "")
+)
+
+func runVersion(ctx context.Context, cmd *base.Command, args []string) {
+	if len(args) == 0 {
+		// If any of this command's flags were passed explicitly, error
+		// out, because they only make sense with arguments.
+		//
+		// Don't error if the flags came from GOFLAGS, since that can be
+		// a reasonable use case. For example, imagine GOFLAGS=-v to
+		// turn "verbose mode" on for all Go commands, which should not
+		// break "go version".
+		var argOnlyFlag string
+		if !base.InGOFLAGS("-m") && *versionM {
+			argOnlyFlag = "-m"
+		} else if !base.InGOFLAGS("-v") && *versionV {
+			argOnlyFlag = "-v"
+		}
+		if argOnlyFlag != "" {
+			fmt.Fprintf(os.Stderr, "go: 'go version' only accepts %s flag with arguments\n", argOnlyFlag)
+			base.SetExitStatus(2)
+			return
+		}
+		fmt.Printf("go version %s %s/%s\n", runtime.Version(), runtime.GOOS, runtime.GOARCH)
+		return
+	}
+
+	for _, arg := range args {
+		info, err := os.Stat(arg)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%v\n", err)
+			base.SetExitStatus(1)
+			continue
+		}
+		if info.IsDir() {
+			scanDir(arg)
+		} else {
+			scanFile(arg, info, true)
+		}
+	}
+}
+
+// scanDir scans a directory for binary to run scanFile on.
+func scanDir(dir string) {
+	filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
+		if d.Type().IsRegular() || d.Type()&fs.ModeSymlink != 0 {
+			info, err := d.Info()
+			if err != nil {
+				if *versionV {
+					fmt.Fprintf(os.Stderr, "%s: %v\n", path, err)
+				}
+				return nil
+			}
+			scanFile(path, info, *versionV)
+		}
+		return nil
+	})
+}
+
+// isGoBinaryCandidate reports whether the file is a candidate to be a Go binary.
+func isGoBinaryCandidate(file string, info fs.FileInfo) bool {
+	if info.Mode().IsRegular() && info.Mode()&0111 != 0 {
+		return true
+	}
+	name := strings.ToLower(file)
+	switch filepath.Ext(name) {
+	case ".so", ".exe", ".dll":
+		return true
+	default:
+		return strings.Contains(name, ".so.")
+	}
+}
+
+// scanFile scans file to try to report the Go and module versions.
+// If mustPrint is true, scanFile will report any error reading file.
+// Otherwise (mustPrint is false, because scanFile is being called
+// by scanDir) scanFile prints nothing for non-Go binaries.
+func scanFile(file string, info fs.FileInfo, mustPrint bool) {
+	if info.Mode()&fs.ModeSymlink != 0 {
+		// Accept file symlinks only.
+		i, err := os.Stat(file)
+		if err != nil || !i.Mode().IsRegular() {
+			if mustPrint {
+				fmt.Fprintf(os.Stderr, "%s: symlink\n", file)
+			}
+			return
+		}
+		info = i
+	}
+
+	bi, err := buildinfo.ReadFile(file)
+	if err != nil {
+		if mustPrint {
+			if pathErr := (*os.PathError)(nil); errors.As(err, &pathErr) && filepath.Clean(pathErr.Path) == filepath.Clean(file) {
+				fmt.Fprintf(os.Stderr, "%v\n", file)
+			} else {
+
+				// Skip errors for non-Go binaries.
+				// buildinfo.ReadFile errors are not fine-grained enough
+				// to know if the file is a Go binary or not,
+				// so try to infer it from the file mode and extension.
+				if isGoBinaryCandidate(file, info) {
+					fmt.Fprintf(os.Stderr, "%s: %v\n", file, err)
+				}
+			}
+		}
+		return
+	}
+
+	fmt.Printf("%s: %s\n", file, bi.GoVersion)
+	bi.GoVersion = "" // suppress printing go version again
+	mod := bi.String()
+	if *versionM && len(mod) > 0 {
+		fmt.Printf("\t%s\n", strings.ReplaceAll(mod[:len(mod)-1], "\n", "\n\t"))
+	}
+}