bind.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

/* posix */
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
#include <signal.h>

/* socket extensions */
#include <sys/uio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/un.h>

/* plan 9 */
#include "lib.h"
#include "sys9.h"

#include "priv.h"

int
bind(int fd, void *a, int alen)
{
	int n, len, cfd;
	Rock *r;
	char msg[128];
	struct sockaddr_in *lip;

	/* assign the address */
	r = _sock_findrock(fd, 0);
	if(r == 0){
		errno = ENOTSOCK;
		return -1;
	}
	if(alen > sizeof(r->addr)){
		errno = ENAMETOOLONG;
		return -1;
	}
	memmove(&r->addr, a, alen);

	/* the rest is IP sepecific */
	if (r->domain != PF_INET)
		return 0;

	cfd = open(r->ctl, O_RDWR);
	if(cfd < 0){
		errno = EBADF;
		return -1;
	}
	lip = (struct sockaddr_in*)&r->addr;
	if(lip->sin_port > 0)
		sprintf(msg, "bind %d", ntohs(lip->sin_port));
	else
		sprintf(msg, "bind *");
	n = write(cfd, msg, strlen(msg));
	if(n < 0){
		errno = EOPNOTSUPP;	/* Improve error reporting!!! */
		close(cfd);
		return -1;
	}
	close(cfd);

	if(lip->sin_port <= 0)
		_sock_ingetaddr(r, lip, &len, "local");

	return 0;
}