// 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.

// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris

package exec

import (
	
	
	
	
	
)

// 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( string) error {
	,  := os.Stat()
	if  != nil {
		return 
	}
	if  := .Mode(); !.IsDir() && &0111 != 0 {
		return nil
	}
	return fs.ErrPermission
}

// 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.
// The result may be an absolute path or a path relative to the current directory.
func ( string) (string, error) {
	// NOTE(rsc): I wish we could use the Plan 9 behavior here
	// (only bypass the path if file begins with / or ./ or ../)
	// but that would not match all the Unix shells.

	if strings.Contains(, "/") {
		 := findExecutable()
		if  == nil {
			return , nil
		}
		return "", &Error{, }
	}
	 := os.Getenv("PATH")
	for ,  := range filepath.SplitList() {
		if  == "" {
			// Unix shell semantics: path element "" means "."
			 = "."
		}
		 := filepath.Join(, )
		if  := findExecutable();  == nil {
			return , nil
		}
	}
	return "", &Error{, ErrNotFound}
}