TCP 네트워크 프로그래밍 - 2 (IPC)

socket을 통한 IPC는 호스트 전용 도메인(Unix domain socket) 혹은 인터넷 도메인 상에서 loopback addr(Local addr)를 사용하게 된다

 

 

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>
	#include <sys/un.h>
	#include <sys/types.h>
	#include <sys/socket.h>
	static void print_usage(char *progname)
	{
	printf("usage : %s [server|client]\n", progname);
	}
	static int do_server(void)
	{
	/*
	socket
	bind
	listen
	accept
	write/read
	*/
	int ret, sockfd, clifd;
	struct sockaddr_un servaddr;
	char buf[128];
	/*
	Address format
	A UNIX domain socket address is represented in the following structure:
	struct sockaddr_un {
	sa_family_t sun_family;
	char sun_path[108];
	};
	*/
	sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
	if(sockfd < 0) {
	perror("socket");
	return -1;
	}
	memset(&servaddr, 0, sizeof(servaddr));
	servaddr.sun_family = AF_UNIX;
	strcpy(servaddr.sun_path, "./sockpath");
	ret = bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
	if(ret < 0) {
	perror("bind");
	close(sockfd);
	return -1;
	}
	ret = listen(sockfd, 8);
	if(ret < 0) {
	perror("listen");
	close(sockfd);
	return -1;
	}
	// socket IPC에서는 클라이언트 정보를 받아올 필요는 없다
	clifd = accept(sockfd, NULL, NULL);
	if(clifd < 0) {
	perror("accept");
	close(sockfd);
	return -1;
	}
	memset(buf, 0, sizeof(buf));
	// recv는 clifd를 socket fd로 전
	recv(clifd, buf, sizeof(buf), 0);
	printf("Received data : %s\n", buf);
	close(sockfd);
	close(clifd);
	return 0;
	}
	static int do_client(void)
	{
	int sockfd, ret;
	struct sockaddr_un cliaddr;
	char buf[128];
	sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
	if(sockfd < 0) {
	perror("socket");
	return -1;
	}
	memset(&cliaddr, 0, sizeof(cliaddr));
	cliaddr.sun_family = AF_UNIX;
	strcpy(cliaddr.sun_path, "./sockpath");
	ret = connect(sockfd, (struct sockaddr *)&cliaddr, sizeof(cliaddr));
	if(ret < 0) {
	perror("connect");
	close(sockfd);
	return -1;
	}
	memset(buf, 0, sizeof(buf));
	snprintf(buf, sizeof(buf), "This is msg from sock_stream");
	ret = send(sockfd, buf, sizeof(buf), 0);
	if(ret < 0) {
	perror("send");
	close(sockfd);
	return -1;
	}
	close(sockfd);
	return 0;
	}
	int main(int argc, char **argv)
	{
	int ret;
	if(argc < 2) {
	print_usage(argv[0]);
	return -1;
	}
	if(!strcmp(argv[1], "server")) {
	ret = do_server();
	} else if(!strcmp(argv[1], "client")) {
	ret = do_client();
	} else {
	print_usage(argv[0]);
	}
	return 0;
	}

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