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// Copyright 2012 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 main
import (
"bytes"
"flag"
"fmt"
"io"
"os"
"os/exec"
"path/filepath"
"sort"
"strconv"
"strings"
"sync"
"time"
)
// pathf is fmt.Sprintf for generating paths
// (on windows it turns / into \ after the printf).
func pathf(format string, args ...interface{}) string {
return filepath.Clean(fmt.Sprintf(format, args...))
}
// filter returns a slice containing the elements x from list for which f(x) == true.
func filter(list []string, f func(string) bool) []string {
var out []string
for _, x := range list {
if f(x) {
out = append(out, x)
}
}
return out
}
// uniq returns a sorted slice containing the unique elements of list.
func uniq(list []string) []string {
out := make([]string, len(list))
copy(out, list)
sort.Strings(out)
keep := out[:0]
for _, x := range out {
if len(keep) == 0 || keep[len(keep)-1] != x {
keep = append(keep, x)
}
}
return keep
}
const (
CheckExit = 1 << iota
ShowOutput
Background
)
var outputLock sync.Mutex
// run is like runEnv with no additional environment.
func run(dir string, mode int, cmd ...string) string {
return runEnv(dir, mode, nil, cmd...)
}
// runEnv runs the command line cmd in dir with additional environment env.
// If mode has ShowOutput set and Background unset, run passes cmd's output to
// stdout/stderr directly. Otherwise, run returns cmd's output as a string.
// If mode has CheckExit set and the command fails, run calls fatalf.
// If mode has Background set, this command is being run as a
// Background job. Only bgrun should use the Background mode,
// not other callers.
func runEnv(dir string, mode int, env []string, cmd ...string) string {
if vflag > 1 {
errprintf("run: %s\n", strings.Join(cmd, " "))
}
xcmd := exec.Command(cmd[0], cmd[1:]...)
if env != nil {
xcmd.Env = append(os.Environ(), env...)
}
setDir(xcmd, dir)
var data []byte
var err error
// If we want to show command output and this is not
// a background command, assume it's the only thing
// running, so we can just let it write directly stdout/stderr
// as it runs without fear of mixing the output with some
// other command's output. Not buffering lets the output
// appear as it is printed instead of once the command exits.
// This is most important for the invocation of 'go build -v bootstrap/...'.
if mode&(Background|ShowOutput) == ShowOutput {
xcmd.Stdout = os.Stdout
xcmd.Stderr = os.Stderr
err = xcmd.Run()
} else {
data, err = xcmd.CombinedOutput()
}
if err != nil && mode&CheckExit != 0 {
outputLock.Lock()
if len(data) > 0 {
xprintf("%s\n", data)
}
outputLock.Unlock()
if mode&Background != 0 {
// Prevent fatalf from waiting on our own goroutine's
// bghelper to exit:
bghelpers.Done()
}
fatalf("FAILED: %v: %v", strings.Join(cmd, " "), err)
}
if mode&ShowOutput != 0 {
outputLock.Lock()
os.Stdout.Write(data)
outputLock.Unlock()
}
if vflag > 2 {
errprintf("run: %s DONE\n", strings.Join(cmd, " "))
}
return string(data)
}
var maxbg = 4 /* maximum number of jobs to run at once */
var (
bgwork = make(chan func(), 1e5)
bghelpers sync.WaitGroup
dieOnce sync.Once // guards close of dying
dying = make(chan struct{})
)
func bginit() {
bghelpers.Add(maxbg)
for i := 0; i < maxbg; i++ {
go bghelper()
}
}
func bghelper() {
defer bghelpers.Done()
for {
select {
case <-dying:
return
case w := <-bgwork:
// Dying takes precedence over doing more work.
select {
case <-dying:
return
default:
w()
}
}
}
}
// bgrun is like run but runs the command in the background.
// CheckExit|ShowOutput mode is implied (since output cannot be returned).
// bgrun adds 1 to wg immediately, and calls Done when the work completes.
func bgrun(wg *sync.WaitGroup, dir string, cmd ...string) {
wg.Add(1)
bgwork <- func() {
defer wg.Done()
run(dir, CheckExit|ShowOutput|Background, cmd...)
}
}
// bgwait waits for pending bgruns to finish.
// bgwait must be called from only a single goroutine at a time.
func bgwait(wg *sync.WaitGroup) {
done := make(chan struct{})
go func() {
wg.Wait()
close(done)
}()
select {
case <-done:
case <-dying:
// Don't return to the caller, to avoid reporting additional errors
// to the user.
select {}
}
}
// xgetwd returns the current directory.
func xgetwd() string {
wd, err := os.Getwd()
if err != nil {
fatalf("%s", err)
}
return wd
}
// xrealwd returns the 'real' name for the given path.
// real is defined as what xgetwd returns in that directory.
func xrealwd(path string) string {
old := xgetwd()
if err := os.Chdir(path); err != nil {
fatalf("chdir %s: %v", path, err)
}
real := xgetwd()
if err := os.Chdir(old); err != nil {
fatalf("chdir %s: %v", old, err)
}
return real
}
// isdir reports whether p names an existing directory.
func isdir(p string) bool {
fi, err := os.Stat(p)
return err == nil && fi.IsDir()
}
// isfile reports whether p names an existing file.
func isfile(p string) bool {
fi, err := os.Stat(p)
return err == nil && fi.Mode().IsRegular()
}
// mtime returns the modification time of the file p.
func mtime(p string) time.Time {
fi, err := os.Stat(p)
if err != nil {
return time.Time{}
}
return fi.ModTime()
}
// readfile returns the content of the named file.
func readfile(file string) string {
data, err := os.ReadFile(file)
if err != nil {
fatalf("%v", err)
}
return string(data)
}
const (
writeExec = 1 << iota
writeSkipSame
)
// writefile writes text to the named file, creating it if needed.
// if exec is non-zero, marks the file as executable.
// If the file already exists and has the expected content,
// it is not rewritten, to avoid changing the time stamp.
func writefile(text, file string, flag int) {
new := []byte(text)
if flag&writeSkipSame != 0 {
old, err := os.ReadFile(file)
if err == nil && bytes.Equal(old, new) {
return
}
}
mode := os.FileMode(0666)
if flag&writeExec != 0 {
mode = 0777
}
xremove(file) // in case of symlink tricks by misc/reboot test
err := os.WriteFile(file, new, mode)
if err != nil {
fatalf("%v", err)
}
}
// xmkdir creates the directory p.
func xmkdir(p string) {
err := os.Mkdir(p, 0777)
if err != nil {
fatalf("%v", err)
}
}
// xmkdirall creates the directory p and its parents, as needed.
func xmkdirall(p string) {
err := os.MkdirAll(p, 0777)
if err != nil {
fatalf("%v", err)
}
}
// xremove removes the file p.
func xremove(p string) {
if vflag > 2 {
errprintf("rm %s\n", p)
}
os.Remove(p)
}
// xremoveall removes the file or directory tree rooted at p.
func xremoveall(p string) {
if vflag > 2 {
errprintf("rm -r %s\n", p)
}
os.RemoveAll(p)
}
// xreaddir replaces dst with a list of the names of the files and subdirectories in dir.
// The names are relative to dir; they are not full paths.
func xreaddir(dir string) []string {
f, err := os.Open(dir)
if err != nil {
fatalf("%v", err)
}
defer f.Close()
names, err := f.Readdirnames(-1)
if err != nil {
fatalf("reading %s: %v", dir, err)
}
return names
}
// xworkdir creates a new temporary directory to hold object files
// and returns the name of that directory.
func xworkdir() string {
name, err := os.MkdirTemp(os.Getenv("GOTMPDIR"), "go-tool-dist-")
if err != nil {
fatalf("%v", err)
}
return name
}
// fatalf prints an error message to standard error and exits.
func fatalf(format string, args ...interface{}) {
fmt.Fprintf(os.Stderr, "go tool dist: %s\n", fmt.Sprintf(format, args...))
dieOnce.Do(func() { close(dying) })
// Wait for background goroutines to finish,
// so that exit handler that removes the work directory
// is not fighting with active writes or open files.
bghelpers.Wait()
xexit(2)
}
var atexits []func()
// xexit exits the process with return code n.
func xexit(n int) {
for i := len(atexits) - 1; i >= 0; i-- {
atexits[i]()
}
os.Exit(n)
}
// xatexit schedules the exit-handler f to be run when the program exits.
func xatexit(f func()) {
atexits = append(atexits, f)
}
// xprintf prints a message to standard output.
func xprintf(format string, args ...interface{}) {
fmt.Printf(format, args...)
}
// errprintf prints a message to standard output.
func errprintf(format string, args ...interface{}) {
fmt.Fprintf(os.Stderr, format, args...)
}
// xsamefile reports whether f1 and f2 are the same file (or dir).
func xsamefile(f1, f2 string) bool {
fi1, err1 := os.Stat(f1)
fi2, err2 := os.Stat(f2)
if err1 != nil || err2 != nil {
return f1 == f2
}
return os.SameFile(fi1, fi2)
}
func xgetgoarm() string {
// If we're building on an actual arm system, and not building
// a cross-compiling toolchain, try to exec ourselves
// to detect whether VFP is supported and set the default GOARM.
// Windows requires ARMv7, so we can skip the check.
// We've always assumed Android is ARMv7 too.
if gohostarch == "arm" && goarch == "arm" && goos == gohostos && goos != "windows" && goos != "android" {
// Try to exec ourselves in a mode to detect VFP support.
// Seeing how far it gets determines which instructions failed.
// The test is OS-agnostic.
out := run("", 0, os.Args[0], "-check-goarm")
v1ok := strings.Contains(out, "VFPv1 OK.")
v3ok := strings.Contains(out, "VFPv3 OK.")
if v1ok && v3ok {
return "7"
}
if v1ok {
return "6"
}
return "5"
}
// Otherwise, in the absence of local information, assume GOARM=7.
//
// We used to assume GOARM=5 in certain contexts but not others,
// which produced inconsistent results. For example if you cross-compiled
// for linux/arm from a windows/amd64 machine, you got GOARM=7 binaries,
// but if you cross-compiled for linux/arm from a linux/amd64 machine,
// you got GOARM=5 binaries. Now the default is independent of the
// host operating system, for better reproducibility of builds.
return "7"
}
func min(a, b int) int {
if a < b {
return a
}
return b
}
// elfIsLittleEndian detects if the ELF file is little endian.
func elfIsLittleEndian(fn string) bool {
// read the ELF file header to determine the endianness without using the
// debug/elf package.
file, err := os.Open(fn)
if err != nil {
fatalf("failed to open file to determine endianness: %v", err)
}
defer file.Close()
var hdr [16]byte
if _, err := io.ReadFull(file, hdr[:]); err != nil {
fatalf("failed to read ELF header to determine endianness: %v", err)
}
// hdr[5] is EI_DATA byte, 1 is ELFDATA2LSB and 2 is ELFDATA2MSB
switch hdr[5] {
default:
fatalf("unknown ELF endianness of %s: EI_DATA = %d", fn, hdr[5])
case 1:
return true
case 2:
return false
}
panic("unreachable")
}
// count is a flag.Value that is like a flag.Bool and a flag.Int.
// If used as -name, it increments the count, but -name=x sets the count.
// Used for verbose flag -v.
type count int
func (c *count) String() string {
return fmt.Sprint(int(*c))
}
func (c *count) Set(s string) error {
switch s {
case "true":
*c++
case "false":
*c = 0
default:
n, err := strconv.Atoi(s)
if err != nil {
return fmt.Errorf("invalid count %q", s)
}
*c = count(n)
}
return nil
}
func (c *count) IsBoolFlag() bool {
return true
}
func xflagparse(maxargs int) {
flag.Var((*count)(&vflag), "v", "verbosity")
flag.Parse()
if maxargs >= 0 && flag.NArg() > maxargs {
flag.Usage()
}
}