From fe7dbea00e36d649f072d38070630c53c4efab17 Mon Sep 17 00:00:00 2001
From: =?utf8?q?P=C3=A9ter=20Sur=C3=A1nyi?= <speter.go1@gmail.com>
Date: Thu, 7 Feb 2013 06:41:35 -0800
Subject: [PATCH] os/exec: LookPath on Unix shouldn't look in cwd when PATH is
 empty

R=golang-dev, dave, bradfitz
CC=golang-dev
https://golang.org/cl/7305053
---
 src/pkg/os/exec/lp_unix.go      |  3 ++
 src/pkg/os/exec/lp_unix_test.go | 52 +++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 src/pkg/os/exec/lp_unix_test.go

diff --git a/src/pkg/os/exec/lp_unix.go b/src/pkg/os/exec/lp_unix.go
index 2163221997..1d1ec07da4 100644
--- a/src/pkg/os/exec/lp_unix.go
+++ b/src/pkg/os/exec/lp_unix.go
@@ -42,6 +42,9 @@ func LookPath(file string) (string, error) {
 		return "", &Error{file, err}
 	}
 	pathenv := os.Getenv("PATH")
+	if pathenv == "" {
+		return "", &Error{file, ErrNotFound}
+	}
 	for _, dir := range strings.Split(pathenv, ":") {
 		if dir == "" {
 			// Unix shell semantics: path element "" means "."
diff --git a/src/pkg/os/exec/lp_unix_test.go b/src/pkg/os/exec/lp_unix_test.go
new file mode 100644
index 0000000000..3cba13e427
--- /dev/null
+++ b/src/pkg/os/exec/lp_unix_test.go
@@ -0,0 +1,52 @@
+// Copyright 2013 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 netbsd openbsd
+
+package exec
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+func TestLookPathUnixEmptyPath(t *testing.T) {
+	tmp, err := ioutil.TempDir("", "TestLookPathUnixEmptyPath")
+	if err != nil {
+		t.Fatal("TempDir failed: ", err)
+	}
+	defer os.RemoveAll(tmp)
+	wd, err := os.Getwd()
+	if err != nil {
+		t.Fatal("Getwd failed: ", err)
+	}
+	err = os.Chdir(tmp)
+	if err != nil {
+		t.Fatal("Chdir failed: ", err)
+	}
+	defer os.Chdir(wd)
+
+	f, err := os.OpenFile("exec_me", os.O_CREATE|os.O_EXCL, 0700)
+	if err != nil {
+		t.Fatal("OpenFile failed: ", err)
+	}
+	defer f.Close()
+
+	pathenv := os.Getenv("PATH")
+	defer os.Setenv("PATH", pathenv)
+
+	err = os.Setenv("PATH", "")
+	if err != nil {
+		t.Fatal("Setenv failed: ", err)
+	}
+
+	path, err := LookPath("exec_me")
+	if err == nil {
+		t.Fatal("LookPath found exec_me in empty $PATH")
+	}
+	if path != "" {
+		t.Fatalf("LookPath path == %q when err != nil", path)
+	}
+}
-- 
2.48.1