static char *
getcwd_logical(void)
{
	struct stat lg, phy;
	char *pwd;

	/*
	 * Check that $PWD is an absolute logical pathname referring to
	 * the current working directory.
	 */
	if ((pwd = getenv("PWD")) != NULL && *pwd == '/') {
		if (stat(pwd, &lg) == -1 || stat(".", &phy) == -1)
			return (NULL);
		if (lg.st_dev == phy.st_dev && lg.st_ino == phy.st_ino)
			return (pwd);
	}

	errno = ENOENT;
	return (NULL);
}