Switch uses of os.Getenv that check for empty string to os.LookupEnv.

Whether the variable was found is already returned by syscall.Getenv.
os.Getenv drops this value while os.Lookupenv passes it along.

PiperOrigin-RevId: 351674032

6 files changed, 16 insertions, 17 deletions

diff --git a/pkg/tcpip/link/sharedmem/sharedmem_test.go b/pkg/tcpip/link/sharedmem/sharedmem_test.go
index dd2e1a125..9f5ee43d7 100644
--- a/pkg/tcpip/link/sharedmem/sharedmem_test.go
+++ b/pkg/tcpip/link/sharedmem/sharedmem_test.go
@@ -191,8 +191,8 @@ func shuffle(b []int) {
 }
 
 func createFile(t *testing.T, size int64, initQueue bool) int {
-	tmpDir := os.Getenv("TEST_TMPDIR")
-	if tmpDir == "" {
+	tmpDir, ok := os.LookupEnv("TEST_TMPDIR")
+	if !ok {
 		tmpDir = os.Getenv("TMPDIR")
 	}
 	f, err := ioutil.TempFile(tmpDir, "sharedmem_test")
diff --git a/pkg/test/testutil/testutil.go b/pkg/test/testutil/testutil.go
index 2b2f95c13..a35c7ffa6 100644
--- a/pkg/test/testutil/testutil.go
+++ b/pkg/test/testutil/testutil.go
@@ -83,11 +83,10 @@ func ConfigureExePath() error {
 // TmpDir returns the absolute path to a writable directory that can be used as
 // scratch by the test.
 func TmpDir() string {
-	dir := os.Getenv("TEST_TMPDIR")
-	if dir == "" {
-		dir = "/tmp"
+	if dir, ok := os.LookupEnv("TEST_TMPDIR"); ok {
+		return dir
 	}
-	return dir
+	return "/tmp"
 }
 
 // Logger is a simple logging wrapper.
@@ -543,7 +542,7 @@ func IsStatic(filename string) (bool, error) {
 //
 // See https://docs.bazel.build/versions/master/test-encyclopedia.html#role-of-the-test-runner.
 func TouchShardStatusFile() error {
-	if statusFile := os.Getenv("TEST_SHARD_STATUS_FILE"); statusFile != "" {
+	if statusFile, ok := os.LookupEnv("TEST_SHARD_STATUS_FILE"); ok {
 		cmd := exec.Command("touch", statusFile)
 		if b, err := cmd.CombinedOutput(); err != nil {
 			return fmt.Errorf("touch %q failed:\n output: %s\n error: %s", statusFile, string(b), err.Error())
@@ -565,8 +564,9 @@ func TestIndicesForShard(numTests int) ([]int, error) {
 		shardTotal = 1
 	)
 
-	indexStr, totalStr := os.Getenv("TEST_SHARD_INDEX"), os.Getenv("TEST_TOTAL_SHARDS")
-	if indexStr != "" && totalStr != "" {
+	indexStr, indexOk := os.LookupEnv("TEST_SHARD_INDEX")
+	totalStr, totalOk := os.LookupEnv("TEST_TOTAL_SHARDS")
+	if indexOk && totalOk {
 		// Parse index and total to ints.
 		var err error
 		shardIndex, err = strconv.Atoi(indexStr)
diff --git a/runsc/cmd/gofer_test.go b/runsc/cmd/gofer_test.go
index cbea7f127..fea62a4f4 100644
--- a/runsc/cmd/gofer_test.go
+++ b/runsc/cmd/gofer_test.go
@@ -24,11 +24,10 @@ import (
 )
 
 func tmpDir() string {
-	dir := os.Getenv("TEST_TMPDIR")
-	if dir == "" {
-		dir = "/tmp"
+	if dir, ok := os.LookupEnv("TEST_TMPDIR"); ok {
+		return dir
 	}
-	return dir
+	return "/tmp"
 }
 
 type dir struct {
diff --git a/runsc/config/flags.go b/runsc/config/flags.go
index 02ab9255a..7e738dfdf 100644
--- a/runsc/config/flags.go
+++ b/runsc/config/flags.go
@@ -114,7 +114,7 @@ func NewFromFlags() (*Config, error) {
 	if len(conf.RootDir) == 0 {
 		// If not set, set default root dir to something (hopefully) user-writeable.
 		conf.RootDir = "/var/run/runsc"
-		if runtimeDir := os.Getenv("XDG_RUNTIME_DIR"); runtimeDir != "" {
+		if runtimeDir, ok := os.LookupEnv("XDG_RUNTIME_DIR"); ok {
 			conf.RootDir = filepath.Join(runtimeDir, "runsc")
 		}
 	}
diff --git a/test/root/crictl_test.go b/test/root/crictl_test.go
index fbf134014..c26dc8577 100644
--- a/test/root/crictl_test.go
+++ b/test/root/crictl_test.go
@@ -353,8 +353,8 @@ func setup(t *testing.T) (*criutil.Crictl, func(), error) {
 	// because the shims will be installed there, and containerd may infer
 	// the binary name and search the PATH.
 	runtimeDir := path.Dir(runtime)
-	modifiedPath := os.Getenv("PATH")
-	if modifiedPath != "" {
+	modifiedPath, ok := os.LookupEnv("PATH")
+	if ok {
 		modifiedPath = ":" + modifiedPath // We prepend below.
 	}
 	modifiedPath = path.Dir(getContainerd()) + modifiedPath
diff --git a/website/cmd/server/main.go b/website/cmd/server/main.go
index 9f0092ed6..707a3a8f8 100644
--- a/website/cmd/server/main.go
+++ b/website/cmd/server/main.go
@@ -366,7 +366,7 @@ func registerProfile(mux *http.ServeMux) {
 }
 
 func envFlagString(name, def string) string {
-	if val := os.Getenv(name); val != "" {
+	if val, ok := os.LookupEnv(name); ok {
 		return val
 	}
 	return def