主要注意流程：

STREAM SOCKET：

Server :  socket() --->  bind() ---> listen()  ---> accept()

Client:    scoket() ---> connect()

参考文章一篇就够： http://troydhanson.github.io/misc/Unix_domain_sockets.html

自己写的 一个 Server 和 一个Client：

//Server
//
//  unix_domain_server.c
//  UnixDomainServer
//
//  Created by gtliu on 7/11/13.
//  Copyright (c) 2013 GT. All rights reserved.
//#include "MITLogModule.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stddef.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>#define FUNC_FAIL                           -1
#define FUNC_SUCCESS                        0
#define SOCKADDR_UN_SUN_PATH_MAX_LEN        103  // 104 - 1
#define SER_ACCEPT_CON_NUM                  1/*** Create a server endpoint of a connection.** @param  scok_path: the unix domain socket path* @return return the file descirption if all ok, <0 on err*/
int create_serv_listen(const char *sock_path)
{size_t path_len = strlen(sock_path);if (path_len == 0) {MITLogWrite(MITLOG_LEVEL_ERROR, "socket path can't be empty");return FUNC_FAIL;} else if (path_len > SOCKADDR_UN_SUN_PATH_MAX_LEN) {MITLogWrite(MITLOG_LEVEL_ERROR, "socket path length must less than%d", SOCKADDR_UN_SUN_PATH_MAX_LEN);return FUNC_FAIL;}int fd = 0, size = 0;struct sockaddr_un server_un;memset(&server_un, 0, sizeof(server_un));server_un.sun_family = AF_UNIX;strncpy(server_un.sun_path, sock_path, sizeof(server_un.sun_path) - 1);if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {MITLogWrite(MITLOG_LEVEL_ERROR, "socket() faild:%s", strerror(errno));return FUNC_FAIL;}/* in case it already exists */unlink(sock_path);size = offsetof(struct sockaddr_un, sun_path) + strlen(server_un.sun_path);if (bind(fd, (struct sockaddr *)&server_un, size) < 0) {MITLogWrite(MITLOG_LEVEL_ERROR, "bind() failed:%s", strerror(errno));close(fd);return FUNC_FAIL;}if (listen(fd, 0) < 0) {MITLogWrite(MITLOG_LEVEL_ERROR, "listen() failed:%s", strerror(errno));close(fd);return FUNC_FAIL;}return fd;
}/*** Accept a client's connection and return the relative file descriptor.** @param  listen_fd: the server socket file descriptor* @return return the file descirption if all ok, <0 on err*/
int serv_accept(int listen_fd)
{int child_fd = 0, len = 0;struct sockaddr_un income_un;len = sizeof(income_un);if ((child_fd = accept(listen_fd, (struct sockaddr *)&income_un, &len)) < 0) {MITLogWrite(MITLOG_LEVEL_ERROR, "accept() failed:%s", strerror(errno));/* often errno=EINTR, if signal caught */return FUNC_FAIL;}return child_fd;
}int main(int argc, const char * argv[])
{MITLogOpen("unix_domain_server");char *sock_path = "/tmp/domain_socket_one";if (argc > 1) {sock_path = (char *) argv[1];}MITLogWrite(MITLOG_LEVEL_COMMON, "Starting the server...");int listen_fd = create_serv_listen(sock_path);if (listen_fd == FUNC_FAIL) {return FUNC_FAIL;}MITLogWrite(MITLOG_LEVEL_COMMON, "Wait for the client... listen_fd:%d", listen_fd);int child_fd = serv_accept(listen_fd);if (child_fd == FUNC_FAIL) {close(listen_fd);return FUNC_FAIL;}char recv_buffer[1024] = {0};while (1) {MITLogWrite(MITLOG_LEVEL_COMMON, "Wait for the message...");if(read(child_fd, recv_buffer, sizeof(recv_buffer) - 1) > 0) {printf("Recieve message:%s\n", recv_buffer);}sleep(2);} MITLogClose();return 0;
}

//Client
//
//  main.c
//  UnixDomainClient
//
//  Created by gtliu on 7/11/13.
//  Copyright (c) 2013 GT. All rights reserved.
//#include "MITLogModule.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stddef.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/stat.h>#define FUNC_FAIL                           -1
#define FUNC_SUCCESS                        0
#define SOCKADDR_UN_SUN_PATH_MAX_LEN        103  // 104 - 1
#define SER_ACCEPT_CON_NUM                  1/*** Create a server endpoint of a connection.** @param  scok_path: the unix domain socket path* @return return the file descirption if all ok, <0 on err*/
int client_connection(const char *sock_path)
{size_t path_len = strlen(sock_path);if (path_len == 0) {MITLogWrite(MITLOG_LEVEL_ERROR, "socket path can't be empty");return FUNC_FAIL;} else if (path_len > SOCKADDR_UN_SUN_PATH_MAX_LEN) {MITLogWrite(MITLOG_LEVEL_ERROR, "socket path length must less than%d", SOCKADDR_UN_SUN_PATH_MAX_LEN);return FUNC_FAIL;}int fd = 0, len = 0;if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {MITLogWrite(MITLOG_LEVEL_ERROR, "socket() faild:%s", strerror(errno));return FUNC_FAIL;}struct sockaddr_un client_un;memset(&client_un, 0, sizeof(client_un));client_un.sun_family = AF_UNIX;strncpy(client_un.sun_path, sock_path, sizeof(client_un.sun_path) - 1);len = offsetof(struct sockaddr_un, sun_path) + strlen(client_un.sun_path);if ((connect(fd, (struct sockaddr *)&client_un, len)) < 0) {MITLogWrite(MITLOG_LEVEL_ERROR, "connect() failed:%s", strerror(errno));close(fd);return FUNC_FAIL;}return fd;
}int main(int argc, const char * argv[])
{MITLogOpen("unix_domain_client");char *sock_path = "/tmp/domain_socket_one";if (argc > 1) {sock_path = (char *) argv[1];}MITLogWrite(MITLOG_LEVEL_COMMON, "Starting the client...");int client_fd = client_connection(sock_path);if (client_fd == FUNC_FAIL) {return FUNC_FAIL;}for (int i=1; i < 100; ++i) {MITLogWrite(MITLOG_LEVEL_COMMON, "Send message to server...");char msg[256] = {0};sprintf(msg, "client message :%d", i);if(write(client_fd, msg, strlen(msg)) > 0) {MITLogWrite(MITLOG_LEVEL_COMMON, "Send message :%d success", i);}sleep(2);}MITLogClose();return 0;
}