mirror of
https://github.com/tailscale/tailscale.git
synced 2024-11-25 19:15:34 +00:00
94 lines
2.1 KiB
Go
94 lines
2.1 KiB
Go
// 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"
|
|
"os"
|
|
"path/filepath"
|
|
"strings"
|
|
)
|
|
|
|
// 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 os.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 "", os.ErrNotExist
|
|
}
|
|
|
|
// LookPath searches for an executable named file in the
|
|
// directories named by the PATH environment variable.
|
|
// If file contains a slash, it is tried directly and the PATH is not consulted.
|
|
// LookPath also uses PATHEXT environment variable to match
|
|
// a suitable candidate.
|
|
// The result may be an absolute path or a path relative to the current directory.
|
|
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, `:\/`) {
|
|
if f, err := findExecutable(file, exts); err == nil {
|
|
return f, nil
|
|
} else {
|
|
return "", &Error{file, err}
|
|
}
|
|
}
|
|
if f, err := findExecutable(filepath.Join(".", file), exts); err == nil {
|
|
return f, nil
|
|
}
|
|
path := os.Getenv("path")
|
|
for _, dir := range filepath.SplitList(path) {
|
|
if f, err := findExecutable(filepath.Join(dir, file), exts); err == nil {
|
|
return f, nil
|
|
}
|
|
}
|
|
return "", &Error{file, ErrNotFound}
|
|
}
|