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Diffstat (limited to 'src/os/exec/exec.go')
-rw-r--r--src/os/exec/exec.go135
1 files changed, 78 insertions, 57 deletions
diff --git a/src/os/exec/exec.go b/src/os/exec/exec.go
index 737aaab6a7..9bef38533e 100644
--- a/src/os/exec/exec.go
+++ b/src/os/exec/exec.go
@@ -217,14 +217,24 @@ type Cmd struct {
// available after a call to Wait or Run.
ProcessState *os.ProcessState
- ctx context.Context // nil means none
- Err error // LookPath error, if any.
- childFiles []*os.File
- closeAfterStart []io.Closer
- closeAfterWait []io.Closer
- goroutine []func() error
- goroutineErrs <-chan error // one receive per goroutine
- ctxErr <-chan error // if non nil, receives the error from watchCtx exactly once
+ ctx context.Context // nil means none
+ Err error // LookPath error, if any.
+
+ // childIOFiles holds closers for any of the child process's
+ // stdin, stdout, and/or stderr files that were opened by the Cmd itself
+ // (not supplied by the caller). These should be closed as soon as they
+ // are inherited by the child process.
+ childIOFiles []io.Closer
+
+ // parentIOPipes holds closers for the parent's end of any pipes
+ // connected to the child's stdin, stdout, and/or stderr streams
+ // that were opened by the Cmd itself (not supplied by the caller).
+ // These should be closed after Wait sees the command exit.
+ parentIOPipes []io.Closer
+
+ goroutine []func() error
+ goroutineErrs <-chan error // one receive per goroutine
+ ctxErr <-chan error // if non nil, receives the error from watchCtx exactly once
// For a security release long ago, we created x/sys/execabs,
// which manipulated the unexported lookPathErr error field
@@ -337,14 +347,14 @@ func (c *Cmd) argv() []string {
return []string{c.Path}
}
-func (c *Cmd) stdin() (f *os.File, err error) {
+func (c *Cmd) childStdin() (*os.File, error) {
if c.Stdin == nil {
- f, err = os.Open(os.DevNull)
+ f, err := os.Open(os.DevNull)
if err != nil {
- return
+ return nil, err
}
- c.closeAfterStart = append(c.closeAfterStart, f)
- return
+ c.childIOFiles = append(c.childIOFiles, f)
+ return f, nil
}
if f, ok := c.Stdin.(*os.File); ok {
@@ -353,11 +363,11 @@ func (c *Cmd) stdin() (f *os.File, err error) {
pr, pw, err := os.Pipe()
if err != nil {
- return
+ return nil, err
}
- c.closeAfterStart = append(c.closeAfterStart, pr)
- c.closeAfterWait = append(c.closeAfterWait, pw)
+ c.childIOFiles = append(c.childIOFiles, pr)
+ c.parentIOPipes = append(c.parentIOPipes, pw)
c.goroutine = append(c.goroutine, func() error {
_, err := io.Copy(pw, c.Stdin)
if skipStdinCopyError(err) {
@@ -371,25 +381,29 @@ func (c *Cmd) stdin() (f *os.File, err error) {
return pr, nil
}
-func (c *Cmd) stdout() (f *os.File, err error) {
+func (c *Cmd) childStdout() (*os.File, error) {
return c.writerDescriptor(c.Stdout)
}
-func (c *Cmd) stderr() (f *os.File, err error) {
+func (c *Cmd) childStderr(childStdout *os.File) (*os.File, error) {
if c.Stderr != nil && interfaceEqual(c.Stderr, c.Stdout) {
- return c.childFiles[1], nil
+ return childStdout, nil
}
return c.writerDescriptor(c.Stderr)
}
-func (c *Cmd) writerDescriptor(w io.Writer) (f *os.File, err error) {
+// writerDescriptor returns an os.File to which the child process
+// can write to send data to w.
+//
+// If w is nil, writerDescriptor returns a File that writes to os.DevNull.
+func (c *Cmd) writerDescriptor(w io.Writer) (*os.File, error) {
if w == nil {
- f, err = os.OpenFile(os.DevNull, os.O_WRONLY, 0)
+ f, err := os.OpenFile(os.DevNull, os.O_WRONLY, 0)
if err != nil {
- return
+ return nil, err
}
- c.closeAfterStart = append(c.closeAfterStart, f)
- return
+ c.childIOFiles = append(c.childIOFiles, f)
+ return f, nil
}
if f, ok := w.(*os.File); ok {
@@ -398,11 +412,11 @@ func (c *Cmd) writerDescriptor(w io.Writer) (f *os.File, err error) {
pr, pw, err := os.Pipe()
if err != nil {
- return
+ return nil, err
}
- c.closeAfterStart = append(c.closeAfterStart, pw)
- c.closeAfterWait = append(c.closeAfterWait, pr)
+ c.childIOFiles = append(c.childIOFiles, pw)
+ c.parentIOPipes = append(c.parentIOPipes, pr)
c.goroutine = append(c.goroutine, func() error {
_, err := io.Copy(w, pr)
pr.Close() // in case io.Copy stopped due to write error
@@ -470,12 +484,21 @@ func lookExtensions(path, dir string) (string, error) {
// After a successful call to Start the Wait method must be called in
// order to release associated system resources.
func (c *Cmd) Start() error {
+ started := false
+ defer func() {
+ c.closeDescriptors(c.childIOFiles)
+ c.childIOFiles = nil
+
+ if !started {
+ c.closeDescriptors(c.parentIOPipes)
+ c.parentIOPipes = nil
+ }
+ }()
+
if c.Path == "" && c.Err == nil && c.lookPathErr == nil {
c.Err = errors.New("exec: no command")
}
if c.Err != nil || c.lookPathErr != nil {
- c.closeDescriptors(c.closeAfterStart)
- c.closeDescriptors(c.closeAfterWait)
if c.lookPathErr != nil {
return c.lookPathErr
}
@@ -484,8 +507,6 @@ func (c *Cmd) Start() error {
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
@@ -496,25 +517,28 @@ func (c *Cmd) Start() error {
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)
+ childFiles := make([]*os.File, 0, 3+len(c.ExtraFiles))
+ stdin, err := c.childStdin()
+ if err != nil {
+ return err
}
- c.childFiles = append(c.childFiles, c.ExtraFiles...)
+ childFiles = append(childFiles, stdin)
+ stdout, err := c.childStdout()
+ if err != nil {
+ return err
+ }
+ childFiles = append(childFiles, stdout)
+ stderr, err := c.childStderr(stdout)
+ if err != nil {
+ return err
+ }
+ childFiles = append(childFiles, stderr)
+ childFiles = append(childFiles, c.ExtraFiles...)
env, err := c.environ()
if err != nil {
@@ -523,17 +547,14 @@ func (c *Cmd) Start() error {
c.Process, err = os.StartProcess(c.Path, c.argv(), &os.ProcAttr{
Dir: c.Dir,
- Files: c.childFiles,
+ Files: childFiles,
Env: env,
Sys: c.SysProcAttr,
})
if err != nil {
- c.closeDescriptors(c.closeAfterStart)
- c.closeDescriptors(c.closeAfterWait)
return err
}
-
- c.closeDescriptors(c.closeAfterStart)
+ started = true
// Don't allocate the goroutineErrs channel unless there are goroutines to fire.
if len(c.goroutine) > 0 {
@@ -626,8 +647,8 @@ func (c *Cmd) Wait() error {
err = copyError
}
- c.closeDescriptors(c.closeAfterWait)
- c.closeAfterWait = nil
+ c.closeDescriptors(c.parentIOPipes)
+ c.parentIOPipes = nil
return err
}
@@ -726,9 +747,9 @@ func (c *Cmd) StdinPipe() (io.WriteCloser, error) {
return nil, err
}
c.Stdin = pr
- c.closeAfterStart = append(c.closeAfterStart, pr)
+ c.childIOFiles = append(c.childIOFiles, pr)
wc := &closeOnce{File: pw}
- c.closeAfterWait = append(c.closeAfterWait, wc)
+ c.parentIOPipes = append(c.parentIOPipes, wc)
return wc, nil
}
@@ -768,8 +789,8 @@ func (c *Cmd) StdoutPipe() (io.ReadCloser, error) {
return nil, err
}
c.Stdout = pw
- c.closeAfterStart = append(c.closeAfterStart, pw)
- c.closeAfterWait = append(c.closeAfterWait, pr)
+ c.childIOFiles = append(c.childIOFiles, pw)
+ c.parentIOPipes = append(c.parentIOPipes, pr)
return pr, nil
}
@@ -793,8 +814,8 @@ func (c *Cmd) StderrPipe() (io.ReadCloser, error) {
return nil, err
}
c.Stderr = pw
- c.closeAfterStart = append(c.closeAfterStart, pw)
- c.closeAfterWait = append(c.closeAfterWait, pr)
+ c.childIOFiles = append(c.childIOFiles, pw)
+ c.parentIOPipes = append(c.parentIOPipes, pr)
return pr, nil
}
generated by cgit v1.3 (git 2.53.0) at 2026-04-15 10:44:55 +0000