Dan Willemsen | d279748 | 2017-07-26 13:13:13 -0700 | [diff] [blame] | 1 | // Copyright 2017 The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
Dan Willemsen | cc753b7 | 2021-08-31 13:25:42 -0700 | [diff] [blame] | 5 | //go:build aix || openbsd |
Dan Willemsen | d279748 | 2017-07-26 13:13:13 -0700 | [diff] [blame] | 6 | |
| 7 | package os |
| 8 | |
| 9 | // We query the working directory at init, to use it later to search for the |
| 10 | // executable file |
| 11 | // errWd will be checked later, if we need to use initWd |
| 12 | var initWd, errWd = Getwd() |
| 13 | |
| 14 | func executable() (string, error) { |
| 15 | var exePath string |
| 16 | if len(Args) == 0 || Args[0] == "" { |
| 17 | return "", ErrNotExist |
| 18 | } |
| 19 | if IsPathSeparator(Args[0][0]) { |
| 20 | // Args[0] is an absolute path, so it is the executable. |
| 21 | // Note that we only need to worry about Unix paths here. |
| 22 | exePath = Args[0] |
| 23 | } else { |
| 24 | for i := 1; i < len(Args[0]); i++ { |
| 25 | if IsPathSeparator(Args[0][i]) { |
| 26 | // Args[0] is a relative path: prepend the |
| 27 | // initial working directory. |
| 28 | if errWd != nil { |
| 29 | return "", errWd |
| 30 | } |
| 31 | exePath = initWd + string(PathSeparator) + Args[0] |
| 32 | break |
| 33 | } |
| 34 | } |
| 35 | } |
| 36 | if exePath != "" { |
| 37 | if err := isExecutable(exePath); err != nil { |
| 38 | return "", err |
| 39 | } |
| 40 | return exePath, nil |
| 41 | } |
| 42 | // Search for executable in $PATH. |
| 43 | for _, dir := range splitPathList(Getenv("PATH")) { |
| 44 | if len(dir) == 0 { |
| 45 | dir = "." |
| 46 | } |
| 47 | if !IsPathSeparator(dir[0]) { |
| 48 | if errWd != nil { |
| 49 | return "", errWd |
| 50 | } |
| 51 | dir = initWd + string(PathSeparator) + dir |
| 52 | } |
| 53 | exePath = dir + string(PathSeparator) + Args[0] |
| 54 | switch isExecutable(exePath) { |
| 55 | case nil: |
| 56 | return exePath, nil |
| 57 | case ErrPermission: |
| 58 | return "", ErrPermission |
| 59 | } |
| 60 | } |
| 61 | return "", ErrNotExist |
| 62 | } |
| 63 | |
| 64 | // isExecutable returns an error if a given file is not an executable. |
| 65 | func isExecutable(path string) error { |
| 66 | stat, err := Stat(path) |
| 67 | if err != nil { |
| 68 | return err |
| 69 | } |
| 70 | mode := stat.Mode() |
| 71 | if !mode.IsRegular() { |
| 72 | return ErrPermission |
| 73 | } |
| 74 | if (mode & 0111) == 0 { |
| 75 | return ErrPermission |
| 76 | } |
| 77 | return nil |
| 78 | } |
| 79 | |
| 80 | // splitPathList splits a path list. |
| 81 | // This is based on genSplit from strings/strings.go |
| 82 | func splitPathList(pathList string) []string { |
| 83 | if pathList == "" { |
| 84 | return nil |
| 85 | } |
| 86 | n := 1 |
| 87 | for i := 0; i < len(pathList); i++ { |
| 88 | if pathList[i] == PathListSeparator { |
| 89 | n++ |
| 90 | } |
| 91 | } |
| 92 | start := 0 |
| 93 | a := make([]string, n) |
| 94 | na := 0 |
| 95 | for i := 0; i+1 <= len(pathList) && na+1 < n; i++ { |
| 96 | if pathList[i] == PathListSeparator { |
| 97 | a[na] = pathList[start:i] |
| 98 | na++ |
| 99 | start = i + 1 |
| 100 | } |
| 101 | } |
| 102 | a[na] = pathList[start:] |
| 103 | return a[:na+1] |
| 104 | } |