linux unix socket 通信demo

好，下面是已经整合完善的版本：

✅ 功能点（你要求的全部实现了）：

Unix Domain Socket (SOCK_STREAM)
服务端先启动：正常通信
客户端先启动：等待服务端直到连接成功
客户端每秒发送一条消息
服务端收到后打印并原样回传
服务端断开后，客户端自动重连继续通信
稳定循环运行

📁 项目结构

unix_socket_loop/
├── server.c
└── client.c

✅ server.c（服务端）

// server.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <string.h>
#include <signal.h>#define SOCKET_PATH "/tmp/mysocket"
#define BUFFER_SIZE 128int server_fd = -1;void cleanup() {if (server_fd != -1) close(server_fd);unlink(SOCKET_PATH);printf("Server cleanup done.\n");exit(0);
}int main() {signal(SIGINT, cleanup); // Ctrl+C 退出时清理struct sockaddr_un addr;char buffer[BUFFER_SIZE];// 创建 socketserver_fd = socket(AF_UNIX, SOCK_STREAM, 0);if (server_fd == -1) {perror("socket");exit(EXIT_FAILURE);}unlink(SOCKET_PATH); // 清除旧 socket 文件memset(&addr, 0, sizeof(addr));addr.sun_family = AF_UNIX;strncpy(addr.sun_path, SOCKET_PATH, sizeof(addr.sun_path) - 1);// bind & listenif (bind(server_fd, (struct sockaddr*)&addr, sizeof(addr)) == -1) {perror("bind");exit(EXIT_FAILURE);}if (listen(server_fd, 5) == -1) {perror("listen");exit(EXIT_FAILURE);}printf("Server is listening at %s ...\n", SOCKET_PATH);while (1) {int client_fd = accept(server_fd, NULL, NULL);if (client_fd == -1) {perror("accept");continue;}printf("Client connected.\n");while (1) {memset(buffer, 0, BUFFER_SIZE);ssize_t len = read(client_fd, buffer, BUFFER_SIZE - 1);if (len <= 0) {printf("Client disconnected.\n");close(client_fd);break;}printf("Server received: %s\n", buffer);write(client_fd, buffer, strlen(buffer)); // 回传}}cleanup();
}

✅ client.c（客户端）

// client.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <string.h>
#include <errno.h>#define SOCKET_PATH "/tmp/mysocket"
#define BUFFER_SIZE 128int connect_to_server() {int fd = socket(AF_UNIX, SOCK_STREAM, 0);if (fd == -1) {perror("socket");return -1;}struct sockaddr_un addr;memset(&addr, 0, sizeof(addr));addr.sun_family = AF_UNIX;strncpy(addr.sun_path, SOCKET_PATH, sizeof(addr.sun_path) - 1);while (connect(fd, (struct sockaddr*)&addr, sizeof(addr)) == -1) {printf("Waiting for server... (%s)\n", strerror(errno));sleep(1);}printf("Connected to server.\n");return fd;
}int main() {char buffer[BUFFER_SIZE];int counter = 0;int client_fd = connect_to_server();if (client_fd < 0) {fprintf(stderr, "Failed to connect.\n");return EXIT_FAILURE;}while (1) {snprintf(buffer, BUFFER_SIZE, "Hello %d", counter++);if (write(client_fd, buffer, strlen(buffer)) == -1) {perror("write");close(client_fd);printf("Connection lost. Reconnecting...\n");client_fd = connect_to_server();continue;}memset(buffer, 0, BUFFER_SIZE);ssize_t len = read(client_fd, buffer, BUFFER_SIZE - 1);if (len <= 0) {printf("Server disconnected. Reconnecting...\n");close(client_fd);client_fd = connect_to_server();continue;}printf("Client received: %s\n", buffer);sleep(1);}close(client_fd);return 0;
}

✅ 编译和运行

gcc server.c -o server
gcc client.c -o client

运行服务端（终端1）：

./server

可以先或后运行客户端（终端2）：

./client

✅ 测试行为

测试行为	结果
先运行 client	等待 server 启动后自动连接
server 崩溃后重新启动	client 会自动重连继续发数据
server 收到后打印并回传	正常
client 每秒发送一条数据	正常