pack.go

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