code review 5416060: io: new FileInfo, FileMode types + update tree

src/pkg/os/exec/lp_unix.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.
 
 // +build darwin freebsd linux openbsd
 
 package exec
 
 import (
         "errors"
         "os"
         "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 findExecutable(file string) error {
         d, err := os.Stat(file)
         if err != nil {
                 return err
         }
-        if d.IsRegular() && d.Permission()&0111 != 0 {
+        if m := d.Mode(); !m.IsDir() && m&0111 != 0 {
                 return nil
         }
         return os.EPERM
 }
 
 // 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.
 func LookPath(file string) (string, error) {
         // NOTE(rsc): I wish we could use the Plan 9 behavior here
@@ skipping 12 matching lines @@
                 if dir == "" {
                         // Unix shell semantics: path element "" means "."
                         dir = "."
                 }
                 if err := findExecutable(dir + "/" + file); err == nil {
                         return dir + "/" + file, nil
                 }
         }
         return "", &Error{file, ErrNotFound}
 }