Function xopen

wrapper.c:171–203

* xopen() is the same as open(), but it die()s if the open() fails. */

 * xopen() is the same as open(), but it die()s if the open() fails.
 */
int xopen(const char *path, int oflag, ...)
{
	mode_t mode = 0;
	va_list ap;

	/*
	 * va_arg() will have undefined behavior if the specified type is not
	 * compatible with the argument type. Since integers are promoted to
	 * ints, we fetch the next argument as an int, and then cast it to a
	 * mode_t to avoid undefined behavior.
	 */
	va_start(ap, oflag);
	if (oflag & O_CREAT)
		mode = va_arg(ap, int);
	va_end(ap);

	for (;;) {
		int fd = open(path, oflag, mode);
		if (fd >= 0)
			return fd;
		if (errno == EINTR)
			continue;

		if ((oflag & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
			die_errno(_("unable to create '%s'"), path);
		else if ((oflag & O_RDWR) == O_RDWR)
			die_errno(_("could not open '%s' for reading and writing"), path);
		else if ((oflag & O_WRONLY) == O_WRONLY)
			die_errno(_("could not open '%s' for writing"), path);
		else
			die_errno(_("could not open '%s' for reading"), path);
	}
}

static int handle_nonblock(int fd, short poll_events, int err)
{