1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
|
// Copyright 2010 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"
"io/fs"
"os"
"path/filepath"
"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 chkStat(file string) error {
d, err := os.Stat(file)
if err != nil {
return err
}
if d.IsDir() {
return fs.ErrPermission
}
return nil
}
func hasExt(file string) bool {
i := strings.LastIndex(file, ".")
if i < 0 {
return false
}
return strings.LastIndexAny(file, `:\/`) < i
}
func findExecutable(file string, exts []string) (string, error) {
if len(exts) == 0 {
return file, chkStat(file)
}
if hasExt(file) {
if chkStat(file) == nil {
return file, nil
}
}
for _, e := range exts {
if f := file + e; chkStat(f) == nil {
return f, nil
}
}
return "", fs.ErrNotExist
}
// LookPath searches for an executable named file in the
// directories named by the PATH environment variable.
// LookPath also uses PATHEXT environment variable to match
// a suitable candidate.
// If file contains a slash, it is tried directly and the PATH is not consulted.
// Otherwise, on success, the result is an absolute path.
//
// In older versions of Go, LookPath could return a path relative to the current directory.
// As of Go 1.19, LookPath will instead return that path along with an error satisfying
// errors.Is(err, ErrDot). See the package documentation for more details.
func LookPath(file string) (string, error) {
var exts []string
x := os.Getenv(`PATHEXT`)
if x != "" {
for _, e := range strings.Split(strings.ToLower(x), `;`) {
if e == "" {
continue
}
if e[0] != '.' {
e = "." + e
}
exts = append(exts, e)
}
} else {
exts = []string{".com", ".exe", ".bat", ".cmd"}
}
if strings.ContainsAny(file, `:\/`) {
f, err := findExecutable(file, exts)
if err == nil {
return f, nil
}
return "", &Error{file, err}
}
// On Windows, creating the NoDefaultCurrentDirectoryInExePath
// environment variable (with any value or no value!) signals that
// path lookups should skip the current directory.
// In theory we are supposed to call NeedCurrentDirectoryForExePathW
// "as the registry location of this environment variable can change"
// but that seems exceedingly unlikely: it would break all users who
// have configured their environment this way!
// https://docs.microsoft.com/en-us/windows/win32/api/processenv/nf-processenv-needcurrentdirectoryforexepathw
// See also go.dev/issue/43947.
var (
dotf string
dotErr error
)
if _, found := syscall.Getenv("NoDefaultCurrentDirectoryInExePath"); !found {
if f, err := findExecutable(filepath.Join(".", file), exts); err == nil {
dotf, dotErr = f, &Error{file, ErrDot}
}
}
path := os.Getenv("path")
for _, dir := range filepath.SplitList(path) {
if f, err := findExecutable(filepath.Join(dir, file), exts); err == nil {
if dotErr != nil {
// https://go.dev/issue/53536: if we resolved a relative path implicitly,
// and it is the same executable that would be resolved from the explicit %PATH%,
// prefer the explicit name for the executable (and, likely, no error) instead
// of the equivalent implicit name with ErrDot.
//
// Otherwise, return the ErrDot for the implicit path as soon as we find
// out that the explicit one doesn't match.
dotfi, dotfiErr := os.Lstat(dotf)
fi, fiErr := os.Lstat(f)
if dotfiErr != nil || fiErr != nil || !os.SameFile(dotfi, fi) {
return dotf, dotErr
}
}
if !filepath.IsAbs(f) {
return f, &Error{file, ErrDot}
}
return f, nil
}
}
if dotErr != nil {
return dotf, dotErr
}
return "", &Error{file, ErrNotFound}
}
|
