56 lines
1.4 KiB
Go
56 lines
1.4 KiB
Go
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build darwin freebsd linux openbsd
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package exec
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import (
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"errors"
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"os"
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"strings"
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)
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// ErrNotFound is the error resulting if a path search failed to find an executable file.
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var ErrNotFound = errors.New("executable file not found in $PATH")
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func findExecutable(file string) error {
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d, err := os.Stat(file)
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if err != nil {
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return err
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}
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if d.IsRegular() && d.Permission()&0111 != 0 {
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return nil
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}
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return os.EPERM
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}
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// LookPath searches for an executable binary named file
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// in the directories named by the PATH environment variable.
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// If file contains a slash, it is tried directly and the PATH is not consulted.
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func LookPath(file string) (string, error) {
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// NOTE(rsc): I wish we could use the Plan 9 behavior here
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// (only bypass the path if file begins with / or ./ or ../)
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// but that would not match all the Unix shells.
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if strings.Contains(file, "/") {
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err := findExecutable(file)
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if err == nil {
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return file, nil
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}
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return "", &Error{file, err}
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}
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pathenv := os.Getenv("PATH")
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for _, dir := range strings.Split(pathenv, ":") {
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if dir == "" {
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// Unix shell semantics: path element "" means "."
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dir = "."
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}
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if err := findExecutable(dir + "/" + file); err == nil {
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return dir + "/" + file, nil
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}
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}
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return "", &Error{file, ErrNotFound}
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}
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