映射 Socket 到 Standard IO

演示一下 Unix 系统的 C 程序中如何将 Socket 映射到标准IO。

/* sock2stdio.c
 * Heiher 
 */

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

int main(int argc, char * argv[])
{
	int sock, client, addrlen;
	struct sockaddr_in this_addr, peer_addr;
	unsigned short port = 9000;
	pid_t cpid;

	addrlen = sizeof(struct sockaddr_in);
	memset(&this_addr, 0, addrlen);
	memset(&peer_addr, 0, addrlen);

	this_addr.sin_port = htons(port);
	this_addr.sin_family = AF_INET;
	this_addr.sin_addr.s_addr = htonl(INADDR_ANY);

	sock = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
	bind(sock, (struct sockaddr*)&this_addr, addrlen);
	listen(sock, 5);

	while(-1 != (client=accept(sock, (struct sockaddr*)&peer_addr, &addrlen)))
	{
		cpid = fork();
		if(0 > cpid)
		{
			perror("fork() failed!");

			return 1;
		}
		else if(0 == cpid)	/* child */
		{
			close(0);
			close(1);
			close(2);
			dup2(client, 0);
			dup2(client, 1);
			dup2(client, 2);
			close(client);

			execl("/bin/dd", "/bin/dd", "bs=1", NULL);

			return 0;
		}
	}

	return 0;
}

gcc -o sock2stdio sock2stdio.c
./sock2stdio

nc localhost 9000
hello  # Input
hello  # Output

Over!