version.go

Documentation: cmd/go/internal/version

     1  // Copyright 2011 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package version implements the “go version” command.
     6  package version
     7  
     8  import (
     9  	"context"
    10  	"debug/buildinfo"
    11  	"errors"
    12  	"fmt"
    13  	"io/fs"
    14  	"os"
    15  	"path/filepath"
    16  	"runtime"
    17  	"strings"
    18  
    19  	"cmd/go/internal/base"
    20  	"cmd/go/internal/gover"
    21  )
    22  
    23  var CmdVersion = &base.Command{
    24  	UsageLine: "go version [-m] [-v] [file ...]",
    25  	Short:     "print Go version",
    26  	Long: `Version prints the build information for Go binary files.
    27  
    28  Go version reports the Go version used to build each of the named files.
    29  
    30  If no files are named on the command line, go version prints its own
    31  version information.
    32  
    33  If a directory is named, go version walks that directory, recursively,
    34  looking for recognized Go binaries and reporting their versions.
    35  By default, go version does not report unrecognized files found
    36  during a directory scan. The -v flag causes it to report unrecognized files.
    37  
    38  The -m flag causes go version to print each file's embedded
    39  module version information, when available. In the output, the module
    40  information consists of multiple lines following the version line, each
    41  indented by a leading tab character.
    42  
    43  See also: go doc runtime/debug.BuildInfo.
    44  `,
    45  }
    46  
    47  func init() {
    48  	base.AddChdirFlag(&CmdVersion.Flag)
    49  	CmdVersion.Run = runVersion // break init cycle
    50  }
    51  
    52  var (
    53  	versionM = CmdVersion.Flag.Bool("m", false, "")
    54  	versionV = CmdVersion.Flag.Bool("v", false, "")
    55  )
    56  
    57  func runVersion(ctx context.Context, cmd *base.Command, args []string) {
    58  	if len(args) == 0 {
    59  		// If any of this command's flags were passed explicitly, error
    60  		// out, because they only make sense with arguments.
    61  		//
    62  		// Don't error if the flags came from GOFLAGS, since that can be
    63  		// a reasonable use case. For example, imagine GOFLAGS=-v to
    64  		// turn "verbose mode" on for all Go commands, which should not
    65  		// break "go version".
    66  		var argOnlyFlag string
    67  		if !base.InGOFLAGS("-m") && *versionM {
    68  			argOnlyFlag = "-m"
    69  		} else if !base.InGOFLAGS("-v") && *versionV {
    70  			argOnlyFlag = "-v"
    71  		}
    72  		if argOnlyFlag != "" {
    73  			fmt.Fprintf(os.Stderr, "go: 'go version' only accepts %s flag with arguments\n", argOnlyFlag)
    74  			base.SetExitStatus(2)
    75  			return
    76  		}
    77  		v := runtime.Version()
    78  		if gover.TestVersion != "" {
    79  			v = gover.TestVersion + " (TESTGO_VERSION)"
    80  		}
    81  		fmt.Printf("go version %s %s/%s\n", v, runtime.GOOS, runtime.GOARCH)
    82  		return
    83  	}
    84  
    85  	for _, arg := range args {
    86  		info, err := os.Stat(arg)
    87  		if err != nil {
    88  			fmt.Fprintf(os.Stderr, "%v\n", err)
    89  			base.SetExitStatus(1)
    90  			continue
    91  		}
    92  		if info.IsDir() {
    93  			scanDir(arg)
    94  		} else {
    95  			scanFile(arg, info, true)
    96  		}
    97  	}
    98  }
    99  
   100  // scanDir scans a directory for binary to run scanFile on.
   101  func scanDir(dir string) {
   102  	filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
   103  		if d.Type().IsRegular() || d.Type()&fs.ModeSymlink != 0 {
   104  			info, err := d.Info()
   105  			if err != nil {
   106  				if *versionV {
   107  					fmt.Fprintf(os.Stderr, "%s: %v\n", path, err)
   108  				}
   109  				return nil
   110  			}
   111  			scanFile(path, info, *versionV)
   112  		}
   113  		return nil
   114  	})
   115  }
   116  
   117  // isGoBinaryCandidate reports whether the file is a candidate to be a Go binary.
   118  func isGoBinaryCandidate(file string, info fs.FileInfo) bool {
   119  	if info.Mode().IsRegular() && info.Mode()&0111 != 0 {
   120  		return true
   121  	}
   122  	name := strings.ToLower(file)
   123  	switch filepath.Ext(name) {
   124  	case ".so", ".exe", ".dll":
   125  		return true
   126  	default:
   127  		return strings.Contains(name, ".so.")
   128  	}
   129  }
   130  
   131  // scanFile scans file to try to report the Go and module versions.
   132  // If mustPrint is true, scanFile will report any error reading file.
   133  // Otherwise (mustPrint is false, because scanFile is being called
   134  // by scanDir) scanFile prints nothing for non-Go binaries.
   135  func scanFile(file string, info fs.FileInfo, mustPrint bool) {
   136  	if info.Mode()&fs.ModeSymlink != 0 {
   137  		// Accept file symlinks only.
   138  		i, err := os.Stat(file)
   139  		if err != nil || !i.Mode().IsRegular() {
   140  			if mustPrint {
   141  				fmt.Fprintf(os.Stderr, "%s: symlink\n", file)
   142  			}
   143  			return
   144  		}
   145  		info = i
   146  	}
   147  
   148  	bi, err := buildinfo.ReadFile(file)
   149  	if err != nil {
   150  		if mustPrint {
   151  			if pathErr := (*os.PathError)(nil); errors.As(err, &pathErr) && filepath.Clean(pathErr.Path) == filepath.Clean(file) {
   152  				fmt.Fprintf(os.Stderr, "%v\n", file)
   153  			} else {
   154  
   155  				// Skip errors for non-Go binaries.
   156  				// buildinfo.ReadFile errors are not fine-grained enough
   157  				// to know if the file is a Go binary or not,
   158  				// so try to infer it from the file mode and extension.
   159  				if isGoBinaryCandidate(file, info) {
   160  					fmt.Fprintf(os.Stderr, "%s: %v\n", file, err)
   161  				}
   162  			}
   163  		}
   164  		return
   165  	}
   166  
   167  	fmt.Printf("%s: %s\n", file, bi.GoVersion)
   168  	bi.GoVersion = "" // suppress printing go version again
   169  	mod := bi.String()
   170  	if *versionM && len(mod) > 0 {
   171  		fmt.Printf("\t%s\n", strings.ReplaceAll(mod[:len(mod)-1], "\n", "\n\t"))
   172  	}
   173  }
   174
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