+static char orig_cwd[PATH_MAX];
+static const char *env_names[] = {
+ GIT_DIR_ENVIRONMENT,
+ GIT_WORK_TREE_ENVIRONMENT,
+ GIT_IMPLICIT_WORK_TREE_ENVIRONMENT,
+ GIT_PREFIX_ENVIRONMENT
+};
+static char *orig_env[4];
+static int saved_environment;
+
+static void save_env(void)
+{
+ int i;
+ if (saved_environment)
+ return;
+ saved_environment = 1;
+ if (!getcwd(orig_cwd, sizeof(orig_cwd)))
+ die_errno("cannot getcwd");
+ for (i = 0; i < ARRAY_SIZE(env_names); i++) {
+ orig_env[i] = getenv(env_names[i]);
+ if (orig_env[i])
+ orig_env[i] = xstrdup(orig_env[i]);
+ }
+}
+
+static void restore_env(void)
+{
+ int i;
+ if (*orig_cwd && chdir(orig_cwd))
+ die_errno("could not move to %s", orig_cwd);
+ for (i = 0; i < ARRAY_SIZE(env_names); i++) {
+ if (orig_env[i])
+ setenv(env_names[i], orig_env[i], 1);
+ else
+ unsetenv(env_names[i]);
+ }
+}