diff --git a/dev/devcam/devcam.go b/dev/devcam/devcam.go
index 894344ba9..ad4c993a7 100644
--- a/dev/devcam/devcam.go
+++ b/dev/devcam/devcam.go
@@ -191,12 +191,12 @@ func checkModtime() error {
 	devcamDir := filepath.Join(camliSrcRoot, "dev", "devcam")
 	d, err := os.Open(devcamDir)
 	if err != nil {
-		log.Fatal(err)
+		return fmt.Errorf("could not read devcam source dir %v: %v", devcamDir, err)
 	}
 	defer d.Close()
 	fis, err := d.Readdir(-1)
 	if err != nil {
-		log.Fatal(err)
+		return fmt.Errorf("could not read devcam source dir %v: %v", devcamDir, err)
 	}
 	for _, fi := range fis {
 		if fi.ModTime().After(binModtime) {
@@ -247,10 +247,13 @@ func build(path string) error {
 
 func main() {
 	cmdmain.CheckCwd = checkCamliSrcRoot
-
-	if err := checkModtime(); err != nil {
-		log.Printf("Skipping freshness check: %v", err)
+	cmdmain.CheckModtime = func() error {
+		if err := checkModtime(); err != nil {
+			log.Printf("Skipping freshness check: %v", err)
+		}
+		return nil
 	}
+
 	// TODO(mpl): usage error is not really correct for devcam.
 	// See if I can reimplement it while still using cmdmain.Main().
 	cmdmain.Main()
diff --git a/pkg/cmdmain/cmdmain.go b/pkg/cmdmain/cmdmain.go
index bc1eff592..776022672 100644
--- a/pkg/cmdmain/cmdmain.go
+++ b/pkg/cmdmain/cmdmain.go
@@ -51,6 +51,9 @@ var (
 	// CheckCwd checks the current working directory, and possibly
 	// changes it, or aborts the run if needed.
 	CheckCwd = func() {}
+	// CheckModtime provides a way to check if the currently running binary
+	// is out of date. If it returns an error, the run is aborted.
+	CheckModtime = func() error { return nil }
 )
 
 var ErrUsage = UsageError("invalid command")
@@ -238,6 +241,10 @@ func Main() {
 	}
 	flag.Parse()
 	CheckCwd()
+	if err := CheckModtime(); err != nil {
+		log.Print(err)
+		Exit(1)
+	}
 
 	args := flag.Args()
 	if *FlagVersion {