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在Linux中通过流式套接字编程(TCP),实现一个并发服务器的访问回显,适合刚学完Linux套接字编程的朋友进行巩固训练
具体功能:recv()
函数,当返回值为0的时候,表示客户端已经关闭套接字,即客户端退出。recv()
收到服务器关闭的信息,然后客户端主动退出#include#include #include #include #include #include #include #include #include #include #include #include #define SERVER_ADDR "172.17.44.154"#define BUFSIZE 100void sigchld_handler(int arg);int main(int argc, const char *argv[]){ int socket_fd, new_fd; struct sockaddr_in server_addr, cli_addr; char buf[BUFSIZE]; int pid; struct sigaction sig; /* 注册中断信号处理函数 */ sig.sa_handler = sigchld_handler; sigaction(SIGCHLD, &sig, NULL); /* 创建套接字,并获取套接字描述符 */ socket_fd = socket(AF_INET, SOCK_STREAM, 0); if (-1 == socket_fd) { perror("socket"); exit(-1); } /* 绑定地址 */ server_addr.sin_family = AF_INET; server_addr.sin_port = htons(5001); inet_pton(AF_INET, SERVER_ADDR, (void*)&server_addr.sin_addr.s_addr); //地址转换 if (-1 == bind(socket_fd, (struct sockaddr*)&server_addr, sizeof(server_addr))) { perror("bind"); exit(-1); } /* 转换为被动连接套接字 */ if (-1 == listen(socket_fd, 5)) { perror("listen"); exit(-1); }#if 0 //单进程服务器 /* 获取已连接套接字 */ socklen_t len = 0; new_fd = accept(socket_fd, (struct sockaddr*)&cli_addr, (socklen_t *)&len); if (-1 == new_fd) { perror("accept"); exit(-1); } printf("accept socket!\nclient ip :%s port:%d\n", inet_ntoa(cli_addr.sin_addr), cli_addr.sin_port); while (1) { memset(buf, 0, BUFSIZE); if (0 == recv(new_fd, buf, BUFSIZE, 0)) { //接受数据 printf("the client is closed\n"); break; } printf("read:%s\n", buf); send(new_fd, buf, BUFSIZE, 0); //回应客户端 } close(new_fd);#else //多进程并发服务器 while (1) { socklen_t len = 0; new_fd = accept(socket_fd, (struct sockaddr*)&cli_addr, (socklen_t *)&len); if (-1 == new_fd) { if (errno == EINTR) continue; //accept可能会被信号中断 perror("accept"); exit(-1); } /* 并发服务器:子进程中进行TCP通信 */ pid = fork(); if (pid == -1) { perror("fork"); exit(0); } else if (pid == 0) { close(socket_fd); //关闭监听套接字 while (1) { memset(buf, 0, BUFSIZE); if (0 == recv(new_fd, buf, BUFSIZE, 0)) { //接受数据,只有当客户端主动关闭的时候,才退出线程,还要对关闭之后的子进程 printf("the client socket %s is closed\n", inet_ntoa((struct in_addr)cli_addr.sin_addr)); close(new_fd); //退出之前记得关闭 已连接套接字 exit(0); //通过信号处理函数进行回收 } getsockname(new_fd, (struct sockaddr*)&cli_addr, (socklen_t *)&len); //获取连接套接字信息 printf("recv client IP:%s data:%s\n", inet_ntoa((struct in_addr)cli_addr.sin_addr), buf); send(new_fd, buf, BUFSIZE, 0); //回应客户端 } } else { close(new_fd); //父进程关闭 已连接套接字 } } #endif close(socket_fd); return 0;}void sigchld_handler(int arg){ int child_pid; if (SIGCHLD == arg) { if ((child_pid = waitpid(-1, NULL, WNOHANG)) == -1) { perror("sigchld"); } printf("a client %d is end\n", child_pid); }}
#include#include #include #include #include #include #include #include #include #include #define SERVER_ADDR "172.17.44.154"#define BUFSIZE 100int main(int argc, const char *argv[]){ int new_fd; struct sockaddr_in server_addr; char buf[BUFSIZE]; /* 创建套接字,并获取套接字描述符 */ new_fd = socket(AF_INET, SOCK_STREAM, 0); if (-1 == new_fd) { perror("socket"); exit(-1); } server_addr.sin_family = AF_INET; server_addr.sin_port = htons(5001); inet_pton(AF_INET, SERVER_ADDR, (void*)&server_addr.sin_addr.s_addr); if (-1 == connect(new_fd, (struct sockaddr*)&server_addr, sizeof(server_addr))) { perror("connect"); exit(-1); } while (1) { printf("input:"); fgets(buf, BUFSIZE, stdin); //获取数据 if (-1 == send(new_fd, buf, BUFSIZE, 0)) { //发送数据 perror("send"); close(new_fd); exit(-1); } if (0 == recv(new_fd, buf, BUFSIZE, 0)) { //收到数据 printf("server closed\n"); break; } printf("recv:%s\n", buf); } close(new_fd); return 0;}
PS:这里是在同一主机下做实验的,所以各个客户端的IP地址都是一样的
正常运行的状态如下:当有一个客户端退出时,服务器会显示信息,但是对其他客户端的服务正常进行:
当服务器主动关闭之后,所有客户端都会收到服务器关闭的信息,并且主动退出:转载地址:http://wxwzi.baihongyu.com/