标签:style blog color 使用 os strong 文件 io
一个tcp的客户端服务器程序
服务器端不变,客户端通过I/O复用轮询键盘输入与socket输入(接收客户端的信息)
服务器端:
1 /*selcet服务器客户端模型: 2 1.客户端关闭后,服务器再向客户端发送信息,第一次会收到一个RST复位报文,第二次会收到SIGPIPE信号,导致服务器关闭,必须对这个信号进行处理: 3 1.在服务器对read返回值为0的情况进行处理,不向客户端发送信息 4 2.signal函数: signal(SIGPIPE, handle) 或者直接忽略signal(SIGPIPE, SIG_IGN) 5 */ 6 #include <stdio.h> 7 #include <stdlib.h> 8 #include <string.h> 9 #include <unistd.h> 10 #include <errno.h> 11 #include <sys/types.h> 12 #include <sys/stat.h> 13 #include <sys/socket.h> 14 #include <arpa/inet.h> 15 #include <signal.h> 16 17 #define ERR_EXIT(m) 18 do { 19 perror(m);20 exit(EXIT_FAILURE);21 }while(0)//宏定义的错误处理 22 23 static void do_service(int fd) 24 { 25 char recvbuf[1024] = {0}; 26 int ret; 27 while(1) 28 { 29 memset(recvbuf, 0, sizeof recvbuf); 30 ret = read(&rt, recvbuf, 1024); 31 sleep(3); 32 if(ret == 0)//关闭客户端时会导致ret == 0 33 printf("no message\n"); 34 else if(ret == -1) 35 { 36 if(errno == EINTR) 37 continue; 38 return ; 39 } 40 rio_writen(fd, recvbuf, 5); 41 } 42 } 43 44 void handle(int signum)//SIGPIPE信号处理函数 45 { 46 printf("hello\n"); 47 } 48 49 int main(int argc, const char *argv[]) 50 { 51 if(signal(SIGPIPE, handle) == SIG_ERR) 52 ERR_EXIT("signal"); 53 54 int listenfd = socket(AF_INET, SOCK_STREAM, 0);//准备一个socketfd 55 if(listenfd == -1 ) 56 ERR_EXIT("listen"); 57 58 int on = 1; 59 if(setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)//setsockopt设置端口复用 60 { 61 close(listenfd); 62 ERR_EXIT("setsockopt"); 63 } 64 65 struct sockaddr_in seraddr; 66 seraddr.sin_family = AF_INET; 67 seraddr.sin_port = htons(8888); 68 seraddr.sin_addr.s_addr = htonl(INADDR_ANY); 69 socklen_t len = sizeof(seraddr); 70 if(bind(listenfd, (struct sockaddr*)&seraddr, len) == -1)//监听socket端口, 71 { 72 close(listenfd); 73 ERR_EXIT("bind"); 74 } 75 //上述过程可以封装到起来,不用全部写入main 76 if(listen(listenfd, 6) == -1) 77 { 78 close(listenfd); 79 ERR_EXIT("listen"); 80 } 81 82 struct sockaddr_in cliaddr; 83 bzero(&cliaddr, sizeof(cliaddr)); 84 socklen_t cli_len = sizeof cliaddr; 85 86 int clientfd; 87 clientfd = accept(listenfd, (struct sockaddr*)&cliaddr, &cli_len); 88 89 if(clientfd == -1) 90 { 91 close(listenfd); 92 ERR_EXIT("accept"); 93 } 94 do_service(clientfd); 95 96 close(clientfd); 97 close(listenfd); 98 return 0; 99 }
1.select客户端:
1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <string.h> 4 #include <errno.h> 5 #include <sys/types.h> 6 #include <sys/socket.h> 7 #include <netinet/in.h> 8 #include <arpa/inet.h> 9 #include <sys/select.h> 10 11 #define ERR_EXIT(m) 12 do { 13 perror(m);14 exit(EXIT_FAILURE);15 }while(0) 16 17 static void do_client(int fd) 18 { 19 char recvbuf[MAXLINE + 1] = {0}; 20 char sendbuf[MAXLINE + 1] = {0}; 21 22 fd_set reade, ready;//将ready集合放入select轮询,每次轮询前将reade赋值给ready 23 FD_ZERO(&reade);//清空reade集合 24 int fd_stdin = fileno(stdin); 25 FD_SET(fd_stdin, &reade); 26 FD_SET(fd, &reade);//将需要监听的文件描述符加入集合 27 int fd_max = (fd_stdin > fd) ? fd_stdin : fd;//select轮询的最大文件描述符 28 29 int ret; 30 while(1) 31 { 32 ready = reade; 33 ret = select( fd_max+1, &ready, NULL, NULL, NULL);//轮询,最后一个参数struct *timeval设置为NULL表示即时轮询(每次轮询间没时间间隔) 34 if(ret < 0) 35 { 36 if(errno == EINTR) 37 continue; 38 ERR_EXIT("select"); 39 }else if(ret == 0)//监听的文件描述符状态未发生变化 40 { 41 continue; 42 } 43 44 if(FD_ISSET(fd_stdin, &ready)) 45 { 46 if(fgets(sendbuf, sizeof(sendbuf), stdin) == NULL) 47 { 48 shutdown(fd, SHUT_WR);//关闭fd的写端,close关闭时关闭整个描述符,若再写的话会导致write返回-1,系统会向客户端进程发送一个SIGPIPE信号,
导致关闭,可以对信号进行signal(SIGPIPE, SIG_IGN)处理,也可将fd_stdin从监听队列删除 49 // close(fd); 50 exit(EXIT_SUCCESS); 51 //break;
52 }else 53 write(fd, sendbuf, strlen(sendbuf)); 54 } 55 56 if(FD_ISSET(fd, &ready)) 57 { 58 int nread = read(fd, recvbuf, MAXLINE); 59 if(nread < 0) 60 ERR_EXIT("read"); 61 if(nread == 0)//如果没接收到消息,打印关闭描述符,退出循环 62 { 63 fprintf(stdout, "fd close\n"); 64 break; 65 } 66 fprintf(stdout, "receive:%s\n", recvbuf);//注意要刷新 67 } 68 memset(recvbuf, 0, sizeof recvbuf); 69 memset(sendbuf, 0, sizeof sendbuf); 70 } 71 } 72 73 int main(int argc, const char *argv[]) 74 { 75 int fd = socket(AF_INET, SOCK_STREAM, 0); 76 if(fd < 0) 77 ERR_EXIT("socket"); 78 79 struct sockaddr_in cliaddr; 80 cliaddr.sin_family = AF_INET; 81 cliaddr.sin_port = htons(8888); 82 cliaddr.sin_addr.s_addr = inet_addr("127.0.0.1"); 83 socklen_t len = sizeof cliaddr; 84 85 int ret ; 86 if((ret = connect(fd, (struct sockaddr*)&cliaddr, len)) == -1) 87 { 88 close(fd); 89 ERR_EXIT("connect"); 90 } 91 do_client(fd); 92 close(fd); 93 printf("123\n"); 94 return 0; 95 }
2.poll客户端:
static void do_client(int fd) { char recvbuf[MAXLINE + 1] = {0}; char sendbuf[MAXLINE + 1] = {0}; struct pollfd pfd[2];//struct pollfd数组,里面存放监听描述符相关信息,供poll轮询使用 pfd[0].fd = fileno(stdin); pfd[0].events = POLLIN; pfd[1].fd = fd; pfd[1].events = POLLIN; int ret; while(1) { ret = poll( pfd, 2, -1);//轮询,-1和select中的时间结构体指针为NULL的效果一样 if(ret < 0) { if(errno == EINTR) continue; ERR_EXIT("select"); }else if(ret == 0) { continue; } if(pfd[0].revents & POLLIN) { if(fgets(sendbuf, sizeof(sendbuf), stdin) == NULL) { shutdown(fd, SHUT_WR);//关闭fd的写端 pfd[0].fd = -1; }else write(fd, sendbuf, strlen(sendbuf)); } if(pfd[1].revents & POLLIN) { int nread = read(fd, recvbuf, MAXLINE); if(nread < 0) ERR_EXIT("read"); if(nread == 0)//如果没接收到消息,打印关闭描述符,退出循环 { fprintf(stdout, "fd close\n"); break; } fprintf(stdout, "receive:%s\n", recvbuf);//注意要刷新 } memset(recvbuf, 0, sizeof recvbuf); memset(sendbuf, 0, sizeof sendbuf); } }
//其余部分和select中一样
3.epoll客户端
static void do_client(int fd) { char recvbuf[MAXLINE + 1] = {0}; char sendbuf[MAXLINE + 1] = {0}; int epollfd = epoll_create(2);//返回值也是一个文件描述符,记得要关闭,不然会导致fd耗尽 if(epollfd == -1) ERR_EXIT("epoll_create"); struct epoll_event events[2]; struct epoll_event ev; int ret; ev.data.fd = fd; ev.events = EPOLLIN; ret = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev);//注册fd if(ret == -1) ERR_EXIT("epoll_ctl"); ev.data.fd = fileno(stdin); ev.events = EPOLLIN; ret = epoll_ctl(epollfd, EPOLL_CTL_ADD, STDIN_FILENO, &ev);//注册fd if(ret == -1) ERR_EXIT("epoll_ctl"); int nready; while(1) { nready = epoll_wait(epollfd, events, 2, -1); if(nready < 0) { if(errno == EINTR) continue; ERR_EXIT("select"); }else if(nready == 0) { continue; } int i; for(i = 0; i < nready; i++) { int nfd = events[i].data.fd; if(nfd == STDIN_FILENO) { if(fgets(sendbuf, 1024, stdin) == NULL) { shutdown(fd, SHUT_WR); struct epoll_event ee; ee.data.fd = STDIN_FILENO; if(epoll_ctl(epollfd, EPOLL_CTL_DEL, STDIN_FILENO, &ee) == -1) ERR_EXIT("epoll_ctl"); }else write(fd, sendbuf, strlen(sendbuf)); } if(nfd == fd) { int ret = read(fd, recvbuf, 1024); if(ret == -1) ERR_EXIT("readline"); else if(ret == -1) { close(fd); printf("fd close\n"); exit(EXIT_SUCCESS); } printf("recv data :%s\n", recvbuf); } } } memset(recvbuf, 0, sizeof recvbuf); memset(sendbuf, 0, sizeof sendbuf); }
I/O复用的 select poll和epoll的简单实现,布布扣,bubuko.com
标签:style blog color 使用 os strong 文件 io
原文地址:http://www.cnblogs.com/wj9012/p/3876734.html