From 8221f90f1347bd96548d48b178c8bcb0607cde8f Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Tue, 12 Sep 2023 00:07:55 +0000 Subject: Revert "os/exec: avoid calling LookPath in cmd.Start for resolved paths" This reverts CL 512155. Reason for revert: CL 512155 introduced a race in that it caused cmd.Start to set cmd.Path. Previously it was fine if code looked at cmd.Path in one goroutine while calling cmd.Start in a different goroutine. A test case for this race is in CL 527495. Change-Id: Ic18fdadf6763727f8ea748280d5f0e601b9bf374 Reviewed-on: https://go-review.googlesource.com/c/go/+/527337 Auto-Submit: Ian Lance Taylor Reviewed-by: Ian Lance Taylor LUCI-TryBot-Result: Go LUCI Reviewed-by: Matthew Dempsky --- src/os/exec/exec.go | 36 ++++++++++++++++++++++++++++++++---- 1 file changed, 32 insertions(+), 4 deletions(-) (limited to 'src/os/exec/exec.go') diff --git a/src/os/exec/exec.go b/src/os/exec/exec.go index 2881345fb3..dfede0e7e2 100644 --- a/src/os/exec/exec.go +++ b/src/os/exec/exec.go @@ -590,6 +590,32 @@ func (c *Cmd) Run() error { 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 = "." + string(filepath.Separator) + 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. // // If Start returns successfully, the c.Process field will be set. @@ -623,11 +649,13 @@ func (c *Cmd) Start() error { } return c.Err } - lp, err := lookExtensions(c.Path, c.Dir) - if err != nil { - return err + if runtime.GOOS == "windows" { + lp, err := lookExtensions(c.Path, c.Dir) + if err != nil { + return err + } + c.Path = lp } - c.Path = lp if c.Cancel != nil && c.ctx == nil { return errors.New("exec: command with a non-nil Cancel was not created with CommandContext") } -- cgit v1.3