ref: f48b71b1a985df4b87e9169c893ee79eae456ac5
dir: /sys/src/ape/lib/bsd/accept.c/
/* posix */
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
/* bsd extensions */
#include <sys/uio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/un.h>
#include "priv.h"
int
accept(int fd, void *a, int *alen)
{
	int n, nfd, cfd;
	Rock *r, *nr;
	char name[Ctlsize];
	char file[8+Ctlsize+1];
	char *p, *net;
	r = _sock_findrock(fd, 0);
	if(r == 0){
		errno = ENOTSOCK;
		return -1;
	}
	switch(r->domain){
	case PF_INET:
	case PF_INET6:
		switch(r->stype){
		case SOCK_DGRAM:
			net = "udp";
			break;
		case SOCK_STREAM:
			net = "tcp";
			break;
		case SOCK_RDM:
			net = "il";
			break;
		}
		/* get control file name from listener process */
		n = read(fd, name, sizeof(name)-1);
		if(n <= 0)
			return -1;
		name[n] = 0;
		cfd = open(name, O_RDWR);
		if(cfd < 0)
			return -1;
		nfd = _sock_data(cfd, net, r->domain, r->stype, r->protocol, &nr);
		if(nfd < 0)
			return -1;
		if(write(fd, "OK", 2) < 0){
			close(nfd);
			return -1;
		}
		_sock_ingetaddr(nr, &nr->raddr, 0, "remote");	
		break;
	case PF_UNIX:
		if(r->other >= 0){
			errno = EGREG;
			return -1;
		}
		for(;;){
			/* read path to new connection */
			n = read(fd, name, sizeof(name) - 1);
			if(n < 0)
				return -1;
			if(n == 0)
				continue;
			name[n] = 0;
			/* open new connection */
			_sock_srvname(file, name);
			nfd = open(file, O_RDWR);
			if(nfd < 0)
				continue;
			/* confirm opening on new connection */
			if(write(nfd, name, strlen(name)) > 0)
				break;
			close(nfd);
		}
		nr = _sock_newrock(nfd);
		if(nr == 0){
			close(nfd);
			return -1;
		}
		nr->domain = r->domain;
		nr->stype = r->stype;
		nr->protocol = r->protocol;
		nr->raddr = r->addr;
		break;
	default:
		errno = EOPNOTSUPP;
		return -1;
	}
	if(a != 0)
		getpeername(nfd, a, alen);
	return nfd;
}