| // 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 binary 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} |
| } |