1#define _GNU_SOURCE
 2#include <sys/socket.h>
 3#include <errno.h>
 4#include <fcntl.h>
 5#include "syscall.h"
 6
 7int accept4(int fd, struct sockaddr *restrict addr, socklen_t *restrict len, int flg)
 8{
 9	if (!flg) return accept(fd, addr, len);
10	int ret = socketcall_cp(accept4, fd, addr, len, flg, 0, 0);
11	if (ret>=0 || (errno != ENOSYS && errno != EINVAL)) return ret;
12	if (flg & ~(SOCK_CLOEXEC|SOCK_NONBLOCK)) {
13		errno = EINVAL;
14		return -1;
15	}
16	ret = accept(fd, addr, len);
17	if (ret<0) return ret;
18	if (flg & SOCK_CLOEXEC)
19		__syscall(SYS_fcntl, ret, F_SETFD, FD_CLOEXEC);
20	if (flg & SOCK_NONBLOCK)
21		__syscall(SYS_fcntl, ret, F_SETFL, O_NONBLOCK);
22	return ret;
23}