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tempfork/osexec: remove old fork of os/exec

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This package was a temporary fork of os/exec to fix an EINTR loop
bug that was fixed upstream for Go 1.15 in
8c1db77a92
(https://go-review.googlesource.com/c/go/+/232862), in
src/os/exec_unix.go:

8c1db77a92 (diff-72072cbd53a7240debad8aa506ff7ec795f9cfac7322e779f9bac29a4d0d0bd4)
pull/946/head
Brad Fitzpatrick 4 years ago
parent 5b338bf011
commit 8f76548fd9
19 changed files with 3 additions and 1489 deletions
Show Stats Download Patch File Download Diff File

1
cmd/tailscale/depaware.txt
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@ -67,7 +67,6 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
tailscale.com/safesocket from tailscale.com/cmd/tailscale/cli
💣 tailscale.com/syncs from tailscale.com/net/interfaces+
tailscale.com/tailcfg from tailscale.com/cmd/tailscale/cli+
DW tailscale.com/tempfork/osexec from tailscale.com/portlist
W tailscale.com/tsconst from tailscale.com/net/interfaces
tailscale.com/types/empty from tailscale.com/control/controlclient+
tailscale.com/types/key from tailscale.com/cmd/tailscale/cli+

1
cmd/tailscaled/depaware.txt
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@ -74,7 +74,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
tailscale.com/smallzstd from tailscale.com/ipn/ipnserver+
💣 tailscale.com/syncs from tailscale.com/net/interfaces+
tailscale.com/tailcfg from tailscale.com/control/controlclient+
DW tailscale.com/tempfork/osexec from tailscale.com/portlist
W tailscale.com/tsconst from tailscale.com/net/interfaces
tailscale.com/types/empty from tailscale.com/control/controlclient+
tailscale.com/types/flagtype from tailscale.com/cmd/tailscaled

3
portlist/netstat_exec.go
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@ -8,9 +8,8 @@ package portlist
import (
"fmt"
"os/exec"
"strings"
exec "tailscale.com/tempfork/osexec"
)
var osHideWindow func(*exec.Cmd) // non-nil on Windows; see portlist_windows.go

3
portlist/portlist_macos.go
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@ -12,11 +12,10 @@ import (
"fmt"
"log"
"os"
"os/exec"
"strings"
"sync/atomic"
"time"
exec "tailscale.com/tempfork/osexec"
)
// We have to run netstat, which is a bit expensive, so don't do it too often.

2
portlist/portlist_windows.go
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@ -5,11 +5,11 @@
package portlist
import (
"os/exec"
"syscall"
"time"
"golang.org/x/sys/windows"
exec "tailscale.com/tempfork/osexec"
)
// Forking on Windows is insanely expensive, so don't do it too often.

47
tempfork/osexec/README.md
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@ -1,47 +0,0 @@
This is a temporary fork of Go 1.13's os/exec package,
to work around https://github.com/golang/go/issues/36644.
The main modification (outside of removing some tests that require
internal-only packages to run) is:
```
commit 3c66be240f1ee1f1b5f03bed79eb0d9f8c08965a
Author: Avery Pennarun <apenwarr@gmail.com>
Date: Sun Jan 19 03:17:30 2020 -0500
Cmd.Wait(): handle EINTR return code from os.Process.Wait().
This is probably not actually the correct fix; most likely
os.Process.Wait() itself should be fixed to retry on EINTR so that it
never leaks out of that function. But if we're going to patch a
particular module, it's safer to patch a higher-level one like os/exec
rather than the os module itself.
diff --git a/exec.go b/exec.go
index 17ef003e..5375e673 100644
--- a/exec.go
+++ b/exec.go
@@ -498,7 +498,21 @@ func (c *Cmd) Wait() error {
}
c.finished = true
- state, err := c.Process.Wait()
+ var err error
+ var state *os.ProcessState
+ for {
+ state, err = c.Process.Wait()
+ if err != nil {
+ xe, ok := err.(*os.SyscallError)
+ if ok {
+ if xe.Unwrap() == syscall.EINTR {
+ // temporary error, retry wait syscall
+ continue
+ }
+ }
+ }
+ break
+ }
if c.waitDone != nil {
close(c.waitDone)
}
```

23
tempfork/osexec/bench_test.go
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@ -1,23 +0,0 @@
// Copyright 2019 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 exec
import (
"testing"
)
func BenchmarkExecHostname(b *testing.B) {
b.ReportAllocs()
path, err := LookPath("hostname")
if err != nil {
b.Fatalf("could not find hostname: %v", err)
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
if err := Command(path).Run(); err != nil {
b.Fatalf("hostname: %v", err)
}
}
}

39
tempfork/osexec/env_test.go
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@ -1,39 +0,0 @@
// Copyright 2017 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 exec
import (
"reflect"
"testing"
)
func TestDedupEnv(t *testing.T) {
tests := []struct {
noCase bool
in []string
want []string
}{
{
noCase: true,
in: []string{"k1=v1", "k2=v2", "K1=v3"},
want: []string{"K1=v3", "k2=v2"},
},
{
noCase: false,
in: []string{"k1=v1", "K1=V2", "k1=v3"},
want: []string{"k1=v3", "K1=V2"},
},
{
in: []string{"=a", "=b", "foo", "bar"},
want: []string{"=b", "foo", "bar"},
},
}
for _, tt := range tests {
got := dedupEnvCase(tt.noCase, tt.in)
if !reflect.DeepEqual(got, tt.want) {
t.Errorf("Dedup(%v, %q) = %q; want %q", tt.noCase, tt.in, got, tt.want)
}
}
}

156
tempfork/osexec/example_test.go
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@ -1,156 +0,0 @@
// 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 exec_test
import (
"bytes"
"context"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"log"
"os"
"os/exec"
"strings"
"time"
)
func ExampleLookPath() {
path, err := exec.LookPath("fortune")
if err != nil {
log.Fatal("installing fortune is in your future")
}
fmt.Printf("fortune is available at %s\n", path)
}
func ExampleCommand() {
cmd := exec.Command("tr", "a-z", "A-Z")
cmd.Stdin = strings.NewReader("some input")
var out bytes.Buffer
cmd.Stdout = &out
err := cmd.Run()
if err != nil {
log.Fatal(err)
}
fmt.Printf("in all caps: %q\n", out.String())
}
func ExampleCommand_environment() {
cmd := exec.Command("prog")
cmd.Env = append(os.Environ(),
"FOO=duplicate_value", // ignored
"FOO=actual_value", // this value is used
)
if err := cmd.Run(); err != nil {
log.Fatal(err)
}
}
func ExampleCmd_Output() {
out, err := exec.Command("date").Output()
if err != nil {
log.Fatal(err)
}
fmt.Printf("The date is %s\n", out)
}
func ExampleCmd_Run() {
cmd := exec.Command("sleep", "1")
log.Printf("Running command and waiting for it to finish...")
err := cmd.Run()
log.Printf("Command finished with error: %v", err)
}
func ExampleCmd_Start() {
cmd := exec.Command("sleep", "5")
err := cmd.Start()
if err != nil {
log.Fatal(err)
}
log.Printf("Waiting for command to finish...")
err = cmd.Wait()
log.Printf("Command finished with error: %v", err)
}
func ExampleCmd_StdoutPipe() {
cmd := exec.Command("echo", "-n", `{"Name": "Bob", "Age": 32}`)
stdout, err := cmd.StdoutPipe()
if err != nil {
log.Fatal(err)
}
if err := cmd.Start(); err != nil {
log.Fatal(err)
}
var person struct {
Name string
Age int
}
if err := json.NewDecoder(stdout).Decode(&person); err != nil {
log.Fatal(err)
}
if err := cmd.Wait(); err != nil {
log.Fatal(err)
}
fmt.Printf("%s is %d years old\n", person.Name, person.Age)
}
func ExampleCmd_StdinPipe() {
cmd := exec.Command("cat")
stdin, err := cmd.StdinPipe()
if err != nil {
log.Fatal(err)
}
go func() {
defer stdin.Close()
io.WriteString(stdin, "values written to stdin are passed to cmd's standard input")
}()
out, err := cmd.CombinedOutput()
if err != nil {
log.Fatal(err)
}
fmt.Printf("%s\n", out)
}
func ExampleCmd_StderrPipe() {
cmd := exec.Command("sh", "-c", "echo stdout; echo 1>&2 stderr")
stderr, err := cmd.StderrPipe()
if err != nil {
log.Fatal(err)
}
if err := cmd.Start(); err != nil {
log.Fatal(err)
}
slurp, _ := ioutil.ReadAll(stderr)
fmt.Printf("%s\n", slurp)
if err := cmd.Wait(); err != nil {
log.Fatal(err)
}
}
func ExampleCmd_CombinedOutput() {
cmd := exec.Command("sh", "-c", "echo stdout; echo 1>&2 stderr")
stdoutStderr, err := cmd.CombinedOutput()
if err != nil {
log.Fatal(err)
}
fmt.Printf("%s\n", stdoutStderr)
}
func ExampleCommandContext() {
ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
defer cancel()
if err := exec.CommandContext(ctx, "sleep", "5").Run(); err != nil {
// This will fail after 100 milliseconds. The 5 second sleep
// will be interrupted.
}
}

797
tempfork/osexec/exec.go
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@ -1,797 +0,0 @@
// Copyright 2009 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 exec runs external commands. It wraps os.StartProcess to make it
// easier to remap stdin and stdout, connect I/O with pipes, and do other
// adjustments.
//
// Unlike the "system" library call from C and other languages, the
// os/exec package intentionally does not invoke the system shell and
// does not expand any glob patterns or handle other expansions,
// pipelines, or redirections typically done by shells. The package
// behaves more like C's "exec" family of functions. To expand glob
// patterns, either call the shell directly, taking care to escape any
// dangerous input, or use the path/filepath package's Glob function.
// To expand environment variables, use package os's ExpandEnv.
//
// Note that the examples in this package assume a Unix system.
// They may not run on Windows, and they do not run in the Go Playground
// used by golang.org and godoc.org.
package exec
import (
"bytes"
"context"
"errors"
"io"
"os"
"path/filepath"
"runtime"
"strconv"
"strings"
"sync"
"syscall"
)
// Error is returned by LookPath when it fails to classify a file as an
// executable.
type Error struct {
// Name is the file name for which the error occurred.
Name string
// Err is the underlying error.
Err error
}
func (e *Error) Error() string {
return "exec: " + strconv.Quote(e.Name) + ": " + e.Err.Error()
}
func (e *Error) Unwrap() error { return e.Err }
// Cmd represents an external command being prepared or run.
//
// A Cmd cannot be reused after calling its Run, Output or CombinedOutput
// methods.
type Cmd struct {
// Path is the path of the command to run.
//
// This is the only field that must be set to a non-zero
// value. If Path is relative, it is evaluated relative
// to Dir.
Path string
// Args holds command line arguments, including the command as Args[0].
// If the Args field is empty or nil, Run uses {Path}.
//
// In typical use, both Path and Args are set by calling Command.
Args []string
// Env specifies the environment of the process.
// Each entry is of the form "key=value".
// If Env is nil, the new process uses the current process's
// environment.
// If Env contains duplicate environment keys, only the last
// value in the slice for each duplicate key is used.
// As a special case on Windows, SYSTEMROOT is always added if
// missing and not explicitly set to the empty string.
Env []string
// Dir specifies the working directory of the command.
// If Dir is the empty string, Run runs the command in the
// calling process's current directory.
Dir string
// Stdin specifies the process's standard input.
//
// If Stdin is nil, the process reads from the null device (os.DevNull).
//
// If Stdin is an *os.File, the process's standard input is connected
// directly to that file.
//
// Otherwise, during the execution of the command a separate
// goroutine reads from Stdin and delivers that data to the command
// over a pipe. In this case, Wait does not complete until the goroutine
// stops copying, either because it has reached the end of Stdin
// (EOF or a read error) or because writing to the pipe returned an error.
Stdin io.Reader
// Stdout and Stderr specify the process's standard output and error.
//
// If either is nil, Run connects the corresponding file descriptor
// to the null device (os.DevNull).
//
// If either is an *os.File, the corresponding output from the process
// is connected directly to that file.
//
// Otherwise, during the execution of the command a separate goroutine
// reads from the process over a pipe and delivers that data to the
// corresponding Writer. In this case, Wait does not complete until the
// goroutine reaches EOF or encounters an error.
//
// If Stdout and Stderr are the same writer, and have a type that can
// be compared with ==, at most one goroutine at a time will call Write.
Stdout io.Writer
Stderr io.Writer
// ExtraFiles specifies additional open files to be inherited by the
// new process. It does not include standard input, standard output, or
// standard error. If non-nil, entry i becomes file descriptor 3+i.
//
// ExtraFiles is not supported on Windows.
ExtraFiles []*os.File
// SysProcAttr holds optional, operating system-specific attributes.
// Run passes it to os.StartProcess as the os.ProcAttr's Sys field.
SysProcAttr *syscall.SysProcAttr
// Process is the underlying process, once started.
Process *os.Process
// ProcessState contains information about an exited process,
// available after a call to Wait or Run.
ProcessState *os.ProcessState
ctx context.Context // nil means none
lookPathErr error // LookPath error, if any.
finished bool // when Wait was called
childFiles []*os.File
closeAfterStart []io.Closer
closeAfterWait []io.Closer
goroutine []func() error
errch chan error // one send per goroutine
waitDone chan struct{}
}
// Command returns the Cmd struct to execute the named program with
// the given arguments.
//
// It sets only the Path and Args in the returned structure.
//
// If name contains no path separators, Command uses LookPath to
// resolve name to a complete path if possible. Otherwise it uses name
// directly as Path.
//
// The returned Cmd's Args field is constructed from the command name
// followed by the elements of arg, so arg should not include the
// command name itself. For example, Command("echo", "hello").
// Args[0] is always name, not the possibly resolved Path.
//
// On Windows, processes receive the whole command line as a single string
// and do their own parsing. Command combines and quotes Args into a command
// line string with an algorithm compatible with applications using
// CommandLineToArgvW (which is the most common way). Notable exceptions are
// msiexec.exe and cmd.exe (and thus, all batch files), which have a different
// unquoting algorithm. In these or other similar cases, you can do the
// quoting yourself and provide the full command line in SysProcAttr.CmdLine,
// leaving Args empty.
func Command(name string, arg ...string) *Cmd {
cmd := &Cmd{
Path: name,
Args: append([]string{name}, arg...),
}
if filepath.Base(name) == name {
if lp, err := LookPath(name); err != nil {
cmd.lookPathErr = err
} else {
cmd.Path = lp
}
}
return cmd
}
// CommandContext is like Command but includes a context.
//
// The provided context is used to kill the process (by calling
// os.Process.Kill) if the context becomes done before the command
// completes on its own.
func CommandContext(ctx context.Context, name string, arg ...string) *Cmd {
if ctx == nil {
panic("nil Context")
}
cmd := Command(name, arg...)
cmd.ctx = ctx
return cmd
}
// String returns a human-readable description of c.
// It is intended only for debugging.
// In particular, it is not suitable for use as input to a shell.
// The output of String may vary across Go releases.
func (c *Cmd) String() string {
if c.lookPathErr != nil {
// failed to resolve path; report the original requested path (plus args)
return strings.Join(c.Args, " ")
}
// report the exact executable path (plus args)
b := new(strings.Builder)
b.WriteString(c.Path)
for _, a := range c.Args[1:] {
b.WriteByte(' ')
b.WriteString(a)
}
return b.String()
}
// interfaceEqual protects against panics from doing equality tests on
// two interfaces with non-comparable underlying types.
func interfaceEqual(a, b interface{}) bool {
defer func() {
recover()
}()
return a == b
}
func (c *Cmd) envv() []string {
if c.Env != nil {
return c.Env
}
return os.Environ()
}
func (c *Cmd) argv() []string {
if len(c.Args) > 0 {
return c.Args
}
return []string{c.Path}
}
// skipStdinCopyError optionally specifies a function which reports
// whether the provided stdin copy error should be ignored.
// It is non-nil everywhere but Plan 9, which lacks EPIPE. See exec_posix.go.
var skipStdinCopyError func(error) bool
func (c *Cmd) stdin() (f *os.File, err error) {
if c.Stdin == nil {
f, err = os.Open(os.DevNull)
if err != nil {
return
}
c.closeAfterStart = append(c.closeAfterStart, f)
return
}
if f, ok := c.Stdin.(*os.File); ok {
return f, nil
}
pr, pw, err := os.Pipe()
if err != nil {
return
}
c.closeAfterStart = append(c.closeAfterStart, pr)
c.closeAfterWait = append(c.closeAfterWait, pw)
c.goroutine = append(c.goroutine, func() error {
_, err := io.Copy(pw, c.Stdin)
if skip := skipStdinCopyError; skip != nil && skip(err) {
err = nil
}
if err1 := pw.Close(); err == nil {
err = err1
}
return err
})
return pr, nil
}
func (c *Cmd) stdout() (f *os.File, err error) {
return c.writerDescriptor(c.Stdout)
}
func (c *Cmd) stderr() (f *os.File, err error) {
if c.Stderr != nil && interfaceEqual(c.Stderr, c.Stdout) {
return c.childFiles[1], nil
}
return c.writerDescriptor(c.Stderr)
}
func (c *Cmd) writerDescriptor(w io.Writer) (f *os.File, err error) {
if w == nil {
f, err = os.OpenFile(os.DevNull, os.O_WRONLY, 0)
if err != nil {
return
}
c.closeAfterStart = append(c.closeAfterStart, f)
return
}
if f, ok := w.(*os.File); ok {
return f, nil
}
pr, pw, err := os.Pipe()
if err != nil {
return
}
c.closeAfterStart = append(c.closeAfterStart, pw)
c.closeAfterWait = append(c.closeAfterWait, pr)
c.goroutine = append(c.goroutine, func() error {
_, err := io.Copy(w, pr)
pr.Close() // in case io.Copy stopped due to write error
return err
})
return pw, nil
}
func (c *Cmd) closeDescriptors(closers []io.Closer) {
for _, fd := range closers {
fd.Close()
}
}
// Run starts the specified command and waits for it to complete.
//
// The returned error is nil if the command runs, has no problems
// copying stdin, stdout, and stderr, and exits with a zero exit
// status.
//
// If the command starts but does not complete successfully, the error is of
// type *ExitError. Other error types may be returned for other situations.
//
// If the calling goroutine has locked the operating system thread
// with runtime.LockOSThread and modified any inheritable OS-level
// thread state (for example, Linux or Plan 9 name spaces), the new
// process will inherit the caller's thread state.
func (c *Cmd) Run() error {
if err := c.Start(); err != nil {
return err
}
return c.Wait()
}
// lookExtensions finds windows executable by its dir and path.
// It uses LookPath to try appropriate extensions.
// lookExtensions does not search PATH, instead it converts `prog` into `.\prog`.
func lookExtensions(path, dir string) (string, error) {
if filepath.Base(path) == path {
path = filepath.Join(".", path)
}
if dir == "" {
return LookPath(path)
}
if filepath.VolumeName(path) != "" {
return LookPath(path)
}
if len(path) > 1 && os.IsPathSeparator(path[0]) {
return LookPath(path)
}
dirandpath := filepath.Join(dir, path)
// We assume that LookPath will only add file extension.
lp, err := LookPath(dirandpath)
if err != nil {
return "", err
}
ext := strings.TrimPrefix(lp, dirandpath)
return path + ext, nil
}
// Start starts the specified command but does not wait for it to complete.
//
// The Wait method will return the exit code and release associated resources
// once the command exits.
func (c *Cmd) Start() error {
if c.lookPathErr != nil {
c.closeDescriptors(c.closeAfterStart)
c.closeDescriptors(c.closeAfterWait)
return c.lookPathErr
}
if runtime.GOOS == "windows" {
lp, err := lookExtensions(c.Path, c.Dir)
if err != nil {
c.closeDescriptors(c.closeAfterStart)
c.closeDescriptors(c.closeAfterWait)
return err
}
c.Path = lp
}
if c.Process != nil {
return errors.New("exec: already started")
}
if c.ctx != nil {
select {
case <-c.ctx.Done():
c.closeDescriptors(c.closeAfterStart)
c.closeDescriptors(c.closeAfterWait)
return c.ctx.Err()
default:
}
}
c.childFiles = make([]*os.File, 0, 3+len(c.ExtraFiles))
type F func(*Cmd) (*os.File, error)
for _, setupFd := range []F{(*Cmd).stdin, (*Cmd).stdout, (*Cmd).stderr} {
fd, err := setupFd(c)
if err != nil {
c.closeDescriptors(c.closeAfterStart)
c.closeDescriptors(c.closeAfterWait)
return err
}
c.childFiles = append(c.childFiles, fd)
}
c.childFiles = append(c.childFiles, c.ExtraFiles...)
var err error
c.Process, err = os.StartProcess(c.Path, c.argv(), &os.ProcAttr{
Dir: c.Dir,
Files: c.childFiles,
Env: addCriticalEnv(dedupEnv(c.envv())),
Sys: c.SysProcAttr,
})
if err != nil {
c.closeDescriptors(c.closeAfterStart)
c.closeDescriptors(c.closeAfterWait)
return err
}
c.closeDescriptors(c.closeAfterStart)
// Don't allocate the channel unless there are goroutines to fire.
if len(c.goroutine) > 0 {
c.errch = make(chan error, len(c.goroutine))
for _, fn := range c.goroutine {
go func(fn func() error) {
c.errch <- fn()
}(fn)
}
}
if c.ctx != nil {
c.waitDone = make(chan struct{})
go func() {
select {
case <-c.ctx.Done():
c.Process.Kill()
case <-c.waitDone:
}
}()
}
return nil
}
// An ExitError reports an unsuccessful exit by a command.
type ExitError struct {
*os.ProcessState
// Stderr holds a subset of the standard error output from the
// Cmd.Output method if standard error was not otherwise being
// collected.
//
// If the error output is long, Stderr may contain only a prefix
// and suffix of the output, with the middle replaced with
// text about the number of omitted bytes.
//
// Stderr is provided for debugging, for inclusion in error messages.
// Users with other needs should redirect Cmd.Stderr as needed.
Stderr []byte
}
func (e *ExitError) Error() string {
return e.ProcessState.String()
}
// Wait waits for the command to exit and waits for any copying to
// stdin or copying from stdout or stderr to complete.
//
// The command must have been started by Start.
//
// The returned error is nil if the command runs, has no problems
// copying stdin, stdout, and stderr, and exits with a zero exit
// status.
//
// If the command fails to run or doesn't complete successfully, the
// error is of type *ExitError. Other error types may be
// returned for I/O problems.
//
// If any of c.Stdin, c.Stdout or c.Stderr are not an *os.File, Wait also waits
// for the respective I/O loop copying to or from the process to complete.
//
// Wait releases any resources associated with the Cmd.
func (c *Cmd) Wait() error {
if c.Process == nil {
return errors.New("exec: not started")
}
if c.finished {
return errors.New("exec: Wait was already called")
}
c.finished = true
var err error
var state *os.ProcessState
for {
state, err = c.Process.Wait()
if err != nil {
xe, ok := err.(*os.SyscallError)
if ok {
if xe.Unwrap() == syscall.EINTR {
// temporary error, retry wait syscall
continue
}
}
}
break
}
if c.waitDone != nil {
close(c.waitDone)
}
c.ProcessState = state
var copyError error
for range c.goroutine {
if err := <-c.errch; err != nil && copyError == nil {
copyError = err
}
}
c.closeDescriptors(c.closeAfterWait)
if err != nil {
return err
} else if !state.Success() {
return &ExitError{ProcessState: state}
}
return copyError
}
// Output runs the command and returns its standard output.
// Any returned error will usually be of type *ExitError.
// If c.Stderr was nil, Output populates ExitError.Stderr.
func (c *Cmd) Output() ([]byte, error) {
if c.Stdout != nil {
return nil, errors.New("exec: Stdout already set")
}
var stdout bytes.Buffer
c.Stdout = &stdout
captureErr := c.Stderr == nil
if captureErr {
c.Stderr = &prefixSuffixSaver{N: 32 << 10}
}
err := c.Run()
if err != nil && captureErr {
if ee, ok := err.(*ExitError); ok {
ee.Stderr = c.Stderr.(*prefixSuffixSaver).Bytes()
}
}
return stdout.Bytes(), err
}
// CombinedOutput runs the command and returns its combined standard
// output and standard error.
func (c *Cmd) CombinedOutput() ([]byte, error) {
if c.Stdout != nil {
return nil, errors.New("exec: Stdout already set")
}
if c.Stderr != nil {
return nil, errors.New("exec: Stderr already set")
}
var b bytes.Buffer
c.Stdout = &b
c.Stderr = &b
err := c.Run()
return b.Bytes(), err
}
// StdinPipe returns a pipe that will be connected to the command's
// standard input when the command starts.
// The pipe will be closed automatically after Wait sees the command exit.
// A caller need only call Close to force the pipe to close sooner.
// For example, if the command being run will not exit until standard input
// is closed, the caller must close the pipe.
func (c *Cmd) StdinPipe() (io.WriteCloser, error) {
if c.Stdin != nil {
return nil, errors.New("exec: Stdin already set")
}
if c.Process != nil {
return nil, errors.New("exec: StdinPipe after process started")
}
pr, pw, err := os.Pipe()
if err != nil {
return nil, err
}
c.Stdin = pr
c.closeAfterStart = append(c.closeAfterStart, pr)
wc := &closeOnce{File: pw}
c.closeAfterWait = append(c.closeAfterWait, wc)
return wc, nil
}
type closeOnce struct {
*os.File
once sync.Once
err error
}
func (c *closeOnce) Close() error {
c.once.Do(c.close)
return c.err
}
func (c *closeOnce) close() {
c.err = c.File.Close()
}
// StdoutPipe returns a pipe that will be connected to the command's
// standard output when the command starts.
//
// Wait will close the pipe after seeing the command exit, so most callers
// need not close the pipe themselves; however, an implication is that
// it is incorrect to call Wait before all reads from the pipe have completed.
// For the same reason, it is incorrect to call Run when using StdoutPipe.
// See the example for idiomatic usage.
func (c *Cmd) StdoutPipe() (io.ReadCloser, error) {
if c.Stdout != nil {
return nil, errors.New("exec: Stdout already set")
}
if c.Process != nil {
return nil, errors.New("exec: StdoutPipe after process started")
}
pr, pw, err := os.Pipe()
if err != nil {
return nil, err
}
c.Stdout = pw
c.closeAfterStart = append(c.closeAfterStart, pw)
c.closeAfterWait = append(c.closeAfterWait, pr)
return pr, nil
}
// StderrPipe returns a pipe that will be connected to the command's
// standard error when the command starts.
//
// Wait will close the pipe after seeing the command exit, so most callers
// need not close the pipe themselves; however, an implication is that
// it is incorrect to call Wait before all reads from the pipe have completed.
// For the same reason, it is incorrect to use Run when using StderrPipe.
// See the StdoutPipe example for idiomatic usage.
func (c *Cmd) StderrPipe() (io.ReadCloser, error) {
if c.Stderr != nil {
return nil, errors.New("exec: Stderr already set")
}
if c.Process != nil {
return nil, errors.New("exec: StderrPipe after process started")
}
pr, pw, err := os.Pipe()
if err != nil {
return nil, err
}
c.Stderr = pw
c.closeAfterStart = append(c.closeAfterStart, pw)
c.closeAfterWait = append(c.closeAfterWait, pr)
return pr, nil
}
// prefixSuffixSaver is an io.Writer which retains the first N bytes
// and the last N bytes written to it. The Bytes() methods reconstructs
// it with a pretty error message.
type prefixSuffixSaver struct {
N int // max size of prefix or suffix
prefix []byte
suffix []byte // ring buffer once len(suffix) == N
suffixOff int // offset to write into suffix
skipped int64
// TODO(bradfitz): we could keep one large []byte and use part of it for
// the prefix, reserve space for the '... Omitting N bytes ...' message,
// then the ring buffer suffix, and just rearrange the ring buffer
// suffix when Bytes() is called, but it doesn't seem worth it for
// now just for error messages. It's only ~64KB anyway.
}
func (w *prefixSuffixSaver) Write(p []byte) (n int, err error) {
lenp := len(p)
p = w.fill(&w.prefix, p)
// Only keep the last w.N bytes of suffix data.
if overage := len(p) - w.N; overage > 0 {
p = p[overage:]
w.skipped += int64(overage)
}
p = w.fill(&w.suffix, p)
// w.suffix is full now if p is non-empty. Overwrite it in a circle.
for len(p) > 0 { // 0, 1, or 2 iterations.
n := copy(w.suffix[w.suffixOff:], p)
p = p[n:]
w.skipped += int64(n)
w.suffixOff += n
if w.suffixOff == w.N {
w.suffixOff = 0
}
}
return lenp, nil
}
// fill appends up to len(p) bytes of p to *dst, such that *dst does not
// grow larger than w.N. It returns the un-appended suffix of p.
func (w *prefixSuffixSaver) fill(dst *[]byte, p []byte) (pRemain []byte) {
if remain := w.N - len(*dst); remain > 0 {
add := minInt(len(p), remain)
*dst = append(*dst, p[:add]...)
p = p[add:]
}
return p
}
func (w *prefixSuffixSaver) Bytes() []byte {
if w.suffix == nil {
return w.prefix
}
if w.skipped == 0 {
return append(w.prefix, w.suffix...)
}
var buf bytes.Buffer
buf.Grow(len(w.prefix) + len(w.suffix) + 50)
buf.Write(w.prefix)
buf.WriteString("\n... omitting ")
buf.WriteString(strconv.FormatInt(w.skipped, 10))
buf.WriteString(" bytes ...\n")
buf.Write(w.suffix[w.suffixOff:])
buf.Write(w.suffix[:w.suffixOff])
return buf.Bytes()
}
func minInt(a, b int) int {
if a < b {
return a
}
return b
}
// dedupEnv returns a copy of env with any duplicates removed, in favor of
// later values.
// Items not of the normal environment "key=value" form are preserved unchanged.
func dedupEnv(env []string) []string {
return dedupEnvCase(runtime.GOOS == "windows", env)
}
// dedupEnvCase is dedupEnv with a case option for testing.
// If caseInsensitive is true, the case of keys is ignored.
func dedupEnvCase(caseInsensitive bool, env []string) []string {
out := make([]string, 0, len(env))
saw := make(map[string]int, len(env)) // key => index into out
for _, kv := range env {
eq := strings.Index(kv, "=")
if eq < 0 {
out = append(out, kv)
continue
}
k := kv[:eq]
if caseInsensitive {
k = strings.ToLower(k)
}
if dupIdx, isDup := saw[k]; isDup {
out[dupIdx] = kv
continue
}
saw[k] = len(out)
out = append(out, kv)
}
return out
}
// addCriticalEnv adds any critical environment variables that are required
// (or at least almost always required) on the operating system.
// Currently this is only used for Windows.
func addCriticalEnv(env []string) []string {
if runtime.GOOS != "windows" {
return env
}
for _, kv := range env {
eq := strings.Index(kv, "=")
if eq < 0 {
continue
}
k := kv[:eq]
if strings.EqualFold(k, "SYSTEMROOT") {
// We already have it.
return env
}
}
return append(env, "SYSTEMROOT="+os.Getenv("SYSTEMROOT"))
}

24
tempfork/osexec/exec_unix.go
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@ -1,24 +0,0 @@
// Copyright 2015 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.
// +build !plan9,!windows
package exec
import (
"os"
"syscall"
)
func init() {
skipStdinCopyError = func(err error) bool {
// Ignore EPIPE errors copying to stdin if the program
// completed successfully otherwise.
// See Issue 9173.
pe, ok := err.(*os.PathError)
return ok &&
pe.Op == "write" && pe.Path == "|1" &&
pe.Err == syscall.EPIPE
}
}

23
tempfork/osexec/exec_windows.go
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@ -1,23 +0,0 @@
// Copyright 2017 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 exec
import (
"os"
"syscall"
)
func init() {
skipStdinCopyError = func(err error) bool {
// Ignore ERROR_BROKEN_PIPE and ERROR_NO_DATA errors copying
// to stdin if the program completed successfully otherwise.
// See Issue 20445.
const _ERROR_NO_DATA = syscall.Errno(0xe8)
pe, ok := err.(*os.PathError)
return ok &&
pe.Op == "write" && pe.Path == "|1" &&
(pe.Err == syscall.ERROR_BROKEN_PIPE || pe.Err == _ERROR_NO_DATA)
}
}

61
tempfork/osexec/internal_test.go
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@ -1,61 +0,0 @@
// Copyright 2015 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 exec
import (
"io"
"testing"
)
func TestPrefixSuffixSaver(t *testing.T) {
tests := []struct {
N int
writes []string
want string
}{
{
N: 2,
writes: nil,
want: "",
},
{
N: 2,
writes: []string{"a"},
want: "a",
},
{
N: 2,
writes: []string{"abc", "d"},
want: "abcd",
},
{
N: 2,
writes: []string{"abc", "d", "e"},
want: "ab\n... omitting 1 bytes ...\nde",
},
{
N: 2,
writes: []string{"ab______________________yz"},
want: "ab\n... omitting 22 bytes ...\nyz",
},
{
N: 2,
writes: []string{"ab_______________________y", "z"},
want: "ab\n... omitting 23 bytes ...\nyz",
},
}
for i, tt := range tests {
w := &prefixSuffixSaver{N: tt.N}
for _, s := range tt.writes {
n, err := io.WriteString(w, s)
if err != nil || n != len(s) {
t.Errorf("%d. WriteString(%q) = %v, %v; want %v, %v", i, s, n, err, len(s), nil)
}
}
if got := string(w.Bytes()); got != tt.want {
t.Errorf("%d. Bytes = %q; want %q", i, got, tt.want)
}
}
}

23
tempfork/osexec/lp_js.go
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@ -1,23 +0,0 @@
// Copyright 2018 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.
// +build js,wasm
package exec
import (
"errors"
)
// ErrNotFound is the error resulting if a path search failed to find an executable file.
var ErrNotFound = errors.New("executable file not found in $PATH")
// LookPath searches for an executable named file in the
// directories named by the PATH environment variable.
// If file contains a slash, it is tried directly and the PATH is not consulted.
// The result may be an absolute path or a path relative to the current directory.
func LookPath(file string) (string, error) {
// Wasm can not execute processes, so act as if there are no executables at all.
return "", &Error{file, ErrNotFound}
}

55
tempfork/osexec/lp_plan9.go
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@ -1,55 +0,0 @@
// 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 exec
import (
"errors"
"os"
"path/filepath"
"strings"
)
// ErrNotFound is the error resulting if a path search failed to find an executable file.
var ErrNotFound = errors.New("executable file not found in $path")
func findExecutable(file string) error {
d, err := os.Stat(file)
if err != nil {
return err
}
if m := d.Mode(); !m.IsDir() && m&0111 != 0 {
return nil
}
return os.ErrPermission
}
// LookPath searches for an executable named file in the
// directories named by the path environment variable.
// If file begins with "/", "#", "./", or "../", it is tried
// directly and the path is not consulted.
// The result may be an absolute path or a path relative to the current directory.
func LookPath(file string) (string, error) {
// skip the path lookup for these prefixes
skip := []string{"/", "#", "./", "../"}
for _, p := range skip {
if strings.HasPrefix(file, p) {
err := findExecutable(file)
if err == nil {
return file, nil
}
return "", &Error{file, err}
}
}
path := os.Getenv("path")
for _, dir := range filepath.SplitList(path) {
path := filepath.Join(dir, file)
if err := findExecutable(path); err == nil {
return path, nil
}
}
return "", &Error{file, ErrNotFound}
}

33
tempfork/osexec/lp_test.go
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@ -1,33 +0,0 @@
// 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 exec
import (
"testing"
)
var nonExistentPaths = []string{
"some-non-existent-path",
"non-existent-path/slashed",
}
func TestLookPathNotFound(t *testing.T) {
for _, name := range nonExistentPaths {
path, err := LookPath(name)
if err == nil {
t.Fatalf("LookPath found %q in $PATH", name)
}
if path != "" {
t.Fatalf("LookPath path == %q when err != nil", path)
}
perr, ok := err.(*Error)
if !ok {
t.Fatal("LookPath error is not an exec.Error")
}
if perr.Name != name {
t.Fatalf("want Error name %q, got %q", name, perr.Name)
}
}
}

58
tempfork/osexec/lp_unix.go
Unescape Escape View File

@ -1,58 +0,0 @@
// Copyright 2010 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.
// +build aix darwin dragonfly freebsd linux nacl netbsd openbsd solaris
package exec
import (
"errors"
"os"
"path/filepath"
"strings"
)
// ErrNotFound is the error resulting if a path search failed to find an executable file.
var ErrNotFound = errors.New("executable file not found in $PATH")
func findExecutable(file string) error {
d, err := os.Stat(file)
if err != nil {
return err
}
if m := d.Mode(); !m.IsDir() && m&0111 != 0 {
return nil
}
return os.ErrPermission
}
// LookPath searches for an executable named file in the
// directories named by the PATH environment variable.
// If file contains a slash, it is tried directly and the PATH is not consulted.
// The result may be an absolute path or a path relative to the current directory.
func LookPath(file string) (string, error) {
// NOTE(rsc): I wish we could use the Plan 9 behavior here
// (only bypass the path if file begins with / or ./ or ../)
// but that would not match all the Unix shells.
if strings.Contains(file, "/") {
err := findExecutable(file)
if err == nil {
return file, nil
}
return "", &Error{file, err}
}
path := os.Getenv("PATH")
for _, dir := range filepath.SplitList(path) {
if dir == "" {
// Unix shell semantics: path element "" means "."
dir = "."
}
path := filepath.Join(dir, file)
if err := findExecutable(path); err == nil {
return path, nil
}
}
return "", &Error{file, ErrNotFound}
}

50
tempfork/osexec/lp_unix_test.go
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@ -1,50 +0,0 @@
// Copyright 2013 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.
// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
package exec
import (
"os"
"testing"
)
func TestLookPathUnixEmptyPath(t *testing.T) {
tmp := t.TempDir()
wd, err := os.Getwd()
if err != nil {
t.Fatal("Getwd failed: ", err)
}
err = os.Chdir(tmp)
if err != nil {
t.Fatal("Chdir failed: ", err)
}
defer os.Chdir(wd)
f, err := os.OpenFile("exec_me", os.O_CREATE|os.O_EXCL, 0700)
if err != nil {
t.Fatal("OpenFile failed: ", err)
}
err = f.Close()
if err != nil {
t.Fatal("Close failed: ", err)
}
pathenv := os.Getenv("PATH")
defer os.Setenv("PATH", pathenv)
err = os.Setenv("PATH", "")
if err != nil {
t.Fatal("Setenv failed: ", err)
}
path, err := LookPath("exec_me")
if err == nil {
t.Fatal("LookPath found exec_me in empty $PATH")
}
if path != "" {
t.Fatalf("LookPath path == %q when err != nil", path)
}
}

93
tempfork/osexec/lp_windows.go
Unescape Escape View File

@ -1,93 +0,0 @@
// Copyright 2010 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 exec
import (
"errors"
"os"
"path/filepath"
"strings"
)
// ErrNotFound is the error resulting if a path search failed to find an executable file.
var ErrNotFound = errors.New("executable file not found in %PATH%")
func chkStat(file string) error {
d, err := os.Stat(file)
if err != nil {
return err
}
if d.IsDir() {
return os.ErrPermission
}
return nil
}
func hasExt(file string) bool {
i := strings.LastIndex(file, ".")
if i < 0 {
return false
}
return strings.LastIndexAny(file, `:\/`) < i
}
func findExecutable(file string, exts []string) (string, error) {
if len(exts) == 0 {
return file, chkStat(file)
}
if hasExt(file) {
if chkStat(file) == nil {
return file, nil
}
}
for _, e := range exts {
if f := file + e; chkStat(f) == nil {
return f, nil
}
}
return "", os.ErrNotExist
}
// LookPath searches for an executable named file in the
// directories named by the PATH environment variable.
// If file contains a slash, it is tried directly and the PATH is not consulted.
// LookPath also uses PATHEXT environment variable to match
// a suitable candidate.
// The result may be an absolute path or a path relative to the current directory.
func LookPath(file string) (string, error) {
var exts []string
x := os.Getenv(`PATHEXT`)
if x != "" {
for _, e := range strings.Split(strings.ToLower(x), `;`) {
if e == "" {
continue
}
if e[0] != '.' {
e = "." + e
}
exts = append(exts, e)
}
} else {
exts = []string{".com", ".exe", ".bat", ".cmd"}
}
if strings.ContainsAny(file, `:\/`) {
if f, err := findExecutable(file, exts); err == nil {
return f, nil
} else {
return "", &Error{file, err}
}
}
if f, err := findExecutable(filepath.Join(".", file), exts); err == nil {
return f, nil
}
path := os.Getenv("path")
for _, dir := range filepath.SplitList(path) {
if f, err := findExecutable(filepath.Join(dir, file), exts); err == nil {
return f, nil
}
}
return "", &Error{file, ErrNotFound}
}
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