Function exec_copyin_args

freebsd/kern/kern_exec.c:1155–1222

* Copy out argument and environment strings from the old process address * space into the temporary string buffer. */

 * space into the temporary string buffer.
 */
int
exec_copyin_args(struct image_args *args, const char *fname,
    enum uio_seg segflg, char **argv, char **envv)
{
	u_long arg, env;
	int error;

	bzero(args, sizeof(*args));
	if (argv == NULL)
		return (EFAULT);

	/*
	 * Allocate demand-paged memory for the file name, argument, and
	 * environment strings.
	 */
	error = exec_alloc_args(args);
	if (error != 0)
		return (error);

	/*
	 * Copy the file name.
	 */
	error = exec_args_add_fname(args, fname, segflg);
	if (error != 0)
		goto err_exit;

	/*
	 * extract arguments first
	 */
	for (;;) {
		error = fueword(argv++, &arg);
		if (error == -1) {
			error = EFAULT;
			goto err_exit;
		}
		if (arg == 0)
			break;
		error = exec_args_add_arg(args, (char *)(uintptr_t)arg,
		    UIO_USERSPACE);
		if (error != 0)
			goto err_exit;
	}

	/*
	 * extract environment strings
	 */
	if (envv) {
		for (;;) {
			error = fueword(envv++, &env);
			if (error == -1) {
				error = EFAULT;
				goto err_exit;
			}
			if (env == 0)
				break;
			error = exec_args_add_env(args,
			    (char *)(uintptr_t)env, UIO_USERSPACE);
			if (error != 0)