Unix Domain Socket 域套接字实现

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;}