diff --git a/usr/gen_init_cpio.c b/usr/gen_init_cpio.c
index af8c925e93eb..225ad244cf88 100644
--- a/usr/gen_init_cpio.c
+++ b/usr/gen_init_cpio.c
@@ -382,24 +382,15 @@ error:
 static char *cpio_replace_env(char *new_location)
 {
 	char expanded[PATH_MAX + 1];
-	char env_var[PATH_MAX + 1];
-	char *start;
-	char *end;
+	char *start, *end, *var;
 
-	for (start = NULL; (start = strstr(new_location, "${")); ) {
-		end = strchr(start, '}');
-		if (start < end) {
-			*env_var = *expanded = '\0';
-			strncat(env_var, start + 2, end - start - 2);
-			strncat(expanded, new_location, start - new_location);
-			strncat(expanded, getenv(env_var),
-				PATH_MAX - strlen(expanded));
-			strncat(expanded, end + 1,
-				PATH_MAX - strlen(expanded));
-			strncpy(new_location, expanded, PATH_MAX);
-			new_location[PATH_MAX] = 0;
-		} else
-			break;
+	while ((start = strstr(new_location, "${")) &&
+	       (end = strchr(start + 2, '}'))) {
+		*start = *end = 0;
+		var = getenv(start + 2);
+		snprintf(expanded, sizeof expanded, "%s%s%s",
+			 new_location, var ? var : "", end + 1);
+		strcpy(new_location, expanded);
 	}
 
 	return new_location;