pack.go

Documentation: cmd/distpack

     1  // Copyright 2023 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  // Distpack creates the tgz and zip files for a Go distribution.
     6  // It writes into GOROOT/pkg/distpack:
     7  //
     8  //   - a binary distribution (tgz or zip) for the current GOOS and GOARCH
     9  //   - a source distribution that is independent of GOOS/GOARCH
    10  //   - the module mod, info, and zip files for a distribution in module form
    11  //     (as used by GOTOOLCHAIN support in the go command).
    12  //
    13  // Distpack is typically invoked by the -distpack flag to make.bash.
    14  // A cross-compiled distribution for goos/goarch can be built using:
    15  //
    16  //	GOOS=goos GOARCH=goarch ./make.bash -distpack
    17  //
    18  // To test that the module downloads are usable with the go command:
    19  //
    20  //	./make.bash -distpack
    21  //	mkdir -p /tmp/goproxy/golang.org/toolchain/
    22  //	ln -sf $(pwd)/../pkg/distpack /tmp/goproxy/golang.org/toolchain/@v
    23  //	GOPROXY=file:///tmp/goproxy GOTOOLCHAIN=$(sed 1q ../VERSION) gotip version
    24  //
    25  // gotip can be replaced with an older released Go version once there is one.
    26  // It just can't be the one make.bash built, because it knows it is already that
    27  // version and will skip the download.
    28  package main
    29  
    30  import (
    31  	"archive/tar"
    32  	"archive/zip"
    33  	"compress/flate"
    34  	"compress/gzip"
    35  	"crypto/sha256"
    36  	"flag"
    37  	"fmt"
    38  	"io"
    39  	"io/fs"
    40  	"log"
    41  	"os"
    42  	"path"
    43  	"path/filepath"
    44  	"runtime"
    45  	"strings"
    46  	"time"
    47  
    48  	"cmd/internal/telemetry/counter"
    49  )
    50  
    51  func usage() {
    52  	fmt.Fprintf(os.Stderr, "usage: distpack\n")
    53  	os.Exit(2)
    54  }
    55  
    56  const (
    57  	modPath          = "golang.org/toolchain"
    58  	modVersionPrefix = "v0.0.1"
    59  )
    60  
    61  var (
    62  	goroot     string
    63  	gohostos   string
    64  	gohostarch string
    65  	goos       string
    66  	goarch     string
    67  )
    68  
    69  func main() {
    70  	log.SetPrefix("distpack: ")
    71  	log.SetFlags(0)
    72  	counter.Open()
    73  	flag.Usage = usage
    74  	flag.Parse()
    75  	counter.Inc("distpack/invocations")
    76  	counter.CountFlags("distpack/flag:", *flag.CommandLine)
    77  	if flag.NArg() != 0 {
    78  		usage()
    79  	}
    80  
    81  	// Load context.
    82  	goroot = runtime.GOROOT()
    83  	if goroot == "" {
    84  		log.Fatalf("missing $GOROOT")
    85  	}
    86  	gohostos = runtime.GOOS
    87  	gohostarch = runtime.GOARCH
    88  	goos = os.Getenv("GOOS")
    89  	if goos == "" {
    90  		goos = gohostos
    91  	}
    92  	goarch = os.Getenv("GOARCH")
    93  	if goarch == "" {
    94  		goarch = gohostarch
    95  	}
    96  	goosUnderGoarch := goos + "_" + goarch
    97  	goosDashGoarch := goos + "-" + goarch
    98  	exe := ""
    99  	if goos == "windows" {
   100  		exe = ".exe"
   101  	}
   102  	version, versionTime := readVERSION(goroot)
   103  
   104  	// Start with files from GOROOT, filtering out non-distribution files.
   105  	base, err := NewArchive(goroot)
   106  	if err != nil {
   107  		log.Fatal(err)
   108  	}
   109  	base.SetTime(versionTime)
   110  	base.SetMode(mode)
   111  	base.Remove(
   112  		".git/**",
   113  		".gitattributes",
   114  		".github/**",
   115  		".gitignore",
   116  		"VERSION.cache",
   117  		"misc/cgo/*/_obj/**",
   118  		"**/.DS_Store",
   119  		"**/*.exe~", // go.dev/issue/23894
   120  		// Generated during make.bat/make.bash.
   121  		"src/cmd/dist/dist",
   122  		"src/cmd/dist/dist.exe",
   123  	)
   124  
   125  	// The source distribution removes files generated during the release build.
   126  	// See ../dist/build.go's deptab.
   127  	srcArch := base.Clone()
   128  	srcArch.Remove(
   129  		"bin/**",
   130  		"pkg/**",
   131  
   132  		// Generated during cmd/dist. See ../dist/build.go:/gentab.
   133  		"src/cmd/go/internal/cfg/zdefaultcc.go",
   134  		"src/go/build/zcgo.go",
   135  		"src/runtime/internal/sys/zversion.go",
   136  		"src/time/tzdata/zzipdata.go",
   137  
   138  		// Generated during cmd/dist by bootstrapBuildTools.
   139  		"src/cmd/cgo/zdefaultcc.go",
   140  		"src/cmd/internal/objabi/zbootstrap.go",
   141  		"src/internal/buildcfg/zbootstrap.go",
   142  
   143  		// Generated by earlier versions of cmd/dist .
   144  		"src/cmd/go/internal/cfg/zosarch.go",
   145  	)
   146  	srcArch.AddPrefix("go")
   147  	testSrc(srcArch)
   148  
   149  	// The binary distribution includes only a subset of bin and pkg.
   150  	binArch := base.Clone()
   151  	binArch.Filter(func(name string) bool {
   152  		// Discard bin/ for now, will add back later.
   153  		if strings.HasPrefix(name, "bin/") {
   154  			return false
   155  		}
   156  		// Discard most of pkg.
   157  		if strings.HasPrefix(name, "pkg/") {
   158  			// Keep pkg/include.
   159  			if strings.HasPrefix(name, "pkg/include/") {
   160  				return true
   161  			}
   162  			// Discard other pkg except pkg/tool.
   163  			if !strings.HasPrefix(name, "pkg/tool/") {
   164  				return false
   165  			}
   166  			// Inside pkg/tool, keep only $GOOS_$GOARCH.
   167  			if !strings.HasPrefix(name, "pkg/tool/"+goosUnderGoarch+"/") {
   168  				return false
   169  			}
   170  			// Inside pkg/tool/$GOOS_$GOARCH, discard helper tools.
   171  			switch strings.TrimSuffix(path.Base(name), ".exe") {
   172  			case "api", "dist", "distpack", "metadata":
   173  				return false
   174  			}
   175  		}
   176  		return true
   177  	})
   178  
   179  	// Add go and gofmt to bin, using cross-compiled binaries
   180  	// if this is a cross-compiled distribution.
   181  	binExes := []string{
   182  		"go",
   183  		"gofmt",
   184  	}
   185  	crossBin := "bin"
   186  	if goos != gohostos || goarch != gohostarch {
   187  		crossBin = "bin/" + goosUnderGoarch
   188  	}
   189  	for _, b := range binExes {
   190  		name := "bin/" + b + exe
   191  		src := filepath.Join(goroot, crossBin, b+exe)
   192  		info, err := os.Stat(src)
   193  		if err != nil {
   194  			log.Fatal(err)
   195  		}
   196  		binArch.Add(name, src, info)
   197  	}
   198  	binArch.Sort()
   199  	binArch.SetTime(versionTime) // fix added files
   200  	binArch.SetMode(mode)        // fix added files
   201  
   202  	zipArch := binArch.Clone()
   203  	zipArch.AddPrefix("go")
   204  	testZip(zipArch)
   205  
   206  	// The module distribution is the binary distribution with unnecessary files removed
   207  	// and file names using the necessary prefix for the module.
   208  	modArch := binArch.Clone()
   209  	modArch.Remove(
   210  		"api/**",
   211  		"doc/**",
   212  		"misc/**",
   213  		"test/**",
   214  	)
   215  	modVers := modVersionPrefix + "-" + version + "." + goosDashGoarch
   216  	modArch.AddPrefix(modPath + "@" + modVers)
   217  	modArch.RenameGoMod()
   218  	modArch.Sort()
   219  	testMod(modArch)
   220  
   221  	// distpack returns the full path to name in the distpack directory.
   222  	distpack := func(name string) string {
   223  		return filepath.Join(goroot, "pkg/distpack", name)
   224  	}
   225  	if err := os.MkdirAll(filepath.Join(goroot, "pkg/distpack"), 0777); err != nil {
   226  		log.Fatal(err)
   227  	}
   228  
   229  	writeTgz(distpack(version+".src.tar.gz"), srcArch)
   230  
   231  	if goos == "windows" {
   232  		writeZip(distpack(version+"."+goos+"-"+goarch+".zip"), zipArch)
   233  	} else {
   234  		writeTgz(distpack(version+"."+goos+"-"+goarch+".tar.gz"), zipArch)
   235  	}
   236  
   237  	writeZip(distpack(modVers+".zip"), modArch)
   238  	writeFile(distpack(modVers+".mod"),
   239  		[]byte(fmt.Sprintf("module %s\n", modPath)))
   240  	writeFile(distpack(modVers+".info"),
   241  		[]byte(fmt.Sprintf("{%q:%q, %q:%q}\n",
   242  			"Version", modVers,
   243  			"Time", versionTime.Format(time.RFC3339))))
   244  }
   245  
   246  // mode computes the mode for the given file name.
   247  func mode(name string, _ fs.FileMode) fs.FileMode {
   248  	if strings.HasPrefix(name, "bin/") ||
   249  		strings.HasPrefix(name, "pkg/tool/") ||
   250  		strings.HasSuffix(name, ".bash") ||
   251  		strings.HasSuffix(name, ".sh") ||
   252  		strings.HasSuffix(name, ".pl") ||
   253  		strings.HasSuffix(name, ".rc") {
   254  		return 0o755
   255  	} else if ok, _ := amatch("**/go_?*_?*_exec", name); ok {
   256  		return 0o755
   257  	}
   258  	return 0o644
   259  }
   260  
   261  // readVERSION reads the VERSION file.
   262  // The first line of the file is the Go version.
   263  // Additional lines are 'key value' pairs setting other data.
   264  // The only valid key at the moment is 'time', which sets the modification time for file archives.
   265  func readVERSION(goroot string) (version string, t time.Time) {
   266  	data, err := os.ReadFile(filepath.Join(goroot, "VERSION"))
   267  	if err != nil {
   268  		log.Fatal(err)
   269  	}
   270  	version, rest, _ := strings.Cut(string(data), "\n")
   271  	for _, line := range strings.Split(rest, "\n") {
   272  		f := strings.Fields(line)
   273  		if len(f) == 0 {
   274  			continue
   275  		}
   276  		switch f[0] {
   277  		default:
   278  			log.Fatalf("VERSION: unexpected line: %s", line)
   279  		case "time":
   280  			if len(f) != 2 {
   281  				log.Fatalf("VERSION: unexpected time line: %s", line)
   282  			}
   283  			t, err = time.ParseInLocation(time.RFC3339, f[1], time.UTC)
   284  			if err != nil {
   285  				log.Fatalf("VERSION: bad time: %s", err)
   286  			}
   287  		}
   288  	}
   289  	return version, t
   290  }
   291  
   292  // writeFile writes a file with the given name and data or fatals.
   293  func writeFile(name string, data []byte) {
   294  	if err := os.WriteFile(name, data, 0666); err != nil {
   295  		log.Fatal(err)
   296  	}
   297  	reportHash(name)
   298  }
   299  
   300  // check panics if err is not nil. Otherwise it returns x.
   301  // It is only meant to be used in a function that has deferred
   302  // a function to recover appropriately from the panic.
   303  func check[T any](x T, err error) T {
   304  	check1(err)
   305  	return x
   306  }
   307  
   308  // check1 panics if err is not nil.
   309  // It is only meant to be used in a function that has deferred
   310  // a function to recover appropriately from the panic.
   311  func check1(err error) {
   312  	if err != nil {
   313  		panic(err)
   314  	}
   315  }
   316  
   317  // writeTgz writes the archive in tgz form to the file named name.
   318  func writeTgz(name string, a *Archive) {
   319  	out, err := os.Create(name)
   320  	if err != nil {
   321  		log.Fatal(err)
   322  	}
   323  
   324  	var f File
   325  	defer func() {
   326  		if err := recover(); err != nil {
   327  			extra := ""
   328  			if f.Name != "" {
   329  				extra = " " + f.Name
   330  			}
   331  			log.Fatalf("writing %s%s: %v", name, extra, err)
   332  		}
   333  	}()
   334  
   335  	zw := check(gzip.NewWriterLevel(out, gzip.BestCompression))
   336  	tw := tar.NewWriter(zw)
   337  
   338  	// Find the mode and mtime to use for directory entries,
   339  	// based on the mode and mtime of the first file we see.
   340  	// We know that modes and mtimes are uniform across the archive.
   341  	var dirMode fs.FileMode
   342  	var mtime time.Time
   343  	for _, f := range a.Files {
   344  		dirMode = fs.ModeDir | f.Mode | (f.Mode&0444)>>2 // copy r bits down to x bits
   345  		mtime = f.Time
   346  		break
   347  	}
   348  
   349  	// mkdirAll ensures that the tar file contains directory
   350  	// entries for dir and all its parents. Some programs reading
   351  	// these tar files expect that. See go.dev/issue/61862.
   352  	haveDir := map[string]bool{".": true}
   353  	var mkdirAll func(string)
   354  	mkdirAll = func(dir string) {
   355  		if dir == "/" {
   356  			panic("mkdirAll /")
   357  		}
   358  		if haveDir[dir] {
   359  			return
   360  		}
   361  		haveDir[dir] = true
   362  		mkdirAll(path.Dir(dir))
   363  		df := &File{
   364  			Name: dir + "/",
   365  			Time: mtime,
   366  			Mode: dirMode,
   367  		}
   368  		h := check(tar.FileInfoHeader(df.Info(), ""))
   369  		h.Name = dir + "/"
   370  		if err := tw.WriteHeader(h); err != nil {
   371  			panic(err)
   372  		}
   373  	}
   374  
   375  	for _, f = range a.Files {
   376  		h := check(tar.FileInfoHeader(f.Info(), ""))
   377  		mkdirAll(path.Dir(f.Name))
   378  		h.Name = f.Name
   379  		if err := tw.WriteHeader(h); err != nil {
   380  			panic(err)
   381  		}
   382  		r := check(os.Open(f.Src))
   383  		check(io.Copy(tw, r))
   384  		check1(r.Close())
   385  	}
   386  	f.Name = ""
   387  	check1(tw.Close())
   388  	check1(zw.Close())
   389  	check1(out.Close())
   390  	reportHash(name)
   391  }
   392  
   393  // writeZip writes the archive in zip form to the file named name.
   394  func writeZip(name string, a *Archive) {
   395  	out, err := os.Create(name)
   396  	if err != nil {
   397  		log.Fatal(err)
   398  	}
   399  
   400  	var f File
   401  	defer func() {
   402  		if err := recover(); err != nil {
   403  			extra := ""
   404  			if f.Name != "" {
   405  				extra = " " + f.Name
   406  			}
   407  			log.Fatalf("writing %s%s: %v", name, extra, err)
   408  		}
   409  	}()
   410  
   411  	zw := zip.NewWriter(out)
   412  	zw.RegisterCompressor(zip.Deflate, func(out io.Writer) (io.WriteCloser, error) {
   413  		return flate.NewWriter(out, flate.BestCompression)
   414  	})
   415  	for _, f = range a.Files {
   416  		h := check(zip.FileInfoHeader(f.Info()))
   417  		h.Name = f.Name
   418  		h.Method = zip.Deflate
   419  		w := check(zw.CreateHeader(h))
   420  		r := check(os.Open(f.Src))
   421  		check(io.Copy(w, r))
   422  		check1(r.Close())
   423  	}
   424  	f.Name = ""
   425  	check1(zw.Close())
   426  	check1(out.Close())
   427  	reportHash(name)
   428  }
   429  
   430  func reportHash(name string) {
   431  	f, err := os.Open(name)
   432  	if err != nil {
   433  		log.Fatal(err)
   434  	}
   435  	h := sha256.New()
   436  	io.Copy(h, f)
   437  	f.Close()
   438  	fmt.Printf("distpack: %x %s\n", h.Sum(nil)[:8], filepath.Base(name))
   439  }
   440
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