| // 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" |
| "strings" |
| "syscall" |
| ) |
| |
| // 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 syscall.EPERM |
| } |
| |
| // LookPath searches for an executable binary 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. |
| 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 strings.Split(path, "\000") { |
| if err := findExecutable(dir + "/" + file); err == nil { |
| return dir + "/" + file, nil |
| } |
| } |
| return "", &Error{file, ErrNotFound} |
| } |