linux下socket编程之以select方式实现并发服务器

#include <netinet/in.h> #include <arpa/inet.h> #include <stdio.h> #include <sys/types.h> #include <sys/socket.h> #include <string.h> #include <unistd.h> #include <signal.h> #include <sys/select.h> #define SERVER_PORT 8888 #define BACK_LOG 10 #define MAX_FD 64 /*socket **bind **listen **accept **send/recv */ int main(int argc, char **argv) { int iSocketServer; int iRet; int iSocketClient; int iAddrLen; int fd_sel; unsigned char ucRecvBuf[1024]; int iRecvLen; struct sockaddr_in tSockServerAddr; struct sockaddr_in tSockClientAddr; fd_set read_fd; int max_fd; int i; int read_fds[MAX_FD]; //memset(read_fds, -1, MAX_FD); for(i = 0; i < MAX_FD; i++) { read_fds[i] = -1; } signal(SIGCHLD, SIG_IGN); iSocketServer = socket(AF_INET, SOCK_STREAM, 0); if(iSocketServer == -1){ printf("socket error\n"); return -1; } tSockServerAddr.sin_family = AF_INET; tSockServerAddr.sin_port = htons(SERVER_PORT); tSockServerAddr.sin_addr.s_addr = INADDR_ANY; memset(tSockServerAddr.sin_zero, 0, 8); iRet = bind(iSocketServer, (const struct sockaddr *)&tSockServerAddr, sizeof(struct sockaddr)); if(iRet == -1){ printf("bind error\n"); return -1; } iRet = listen(iSocketServer, BACK_LOG); if(iRet == -1){ printf("listen error\n"); return -1; } max_fd = iSocketServer; read_fds[0] = iSocketServer; while(1) { FD_ZERO(&read_fd); for(i = 0; i < MAX_FD; i++) { if(read_fds[i] != -1) { FD_SET(read_fds[i], &read_fd); if(max_fd < read_fds[i]){ max_fd = read_fds[i]; } } } fd_sel = select(max_fd+1, &read_fd, NULL, NULL, NULL); if(fd_sel == -1){ printf("select error\n"); return -1; } /* 首先判断监听套接字是否有连接 */ if(FD_ISSET(iSocketServer, &read_fd)) { iAddrLen = sizeof(tSockClientAddr); //这个是必须的，否则得到的ip可能不正确 iSocketClient = accept(iSocketServer, (struct sockaddr *)&tSockClientAddr, &iAddrLen); if(iSocketClient == -1){ printf("accept error\n"); return -1; } printf("Get Connect from client%d : %s\n", iSocketClient, inet_ntoa(tSockClientAddr.sin_addr)); for(i = 0; i < MAX_FD; i++) { if(read_fds[i] == -1) { read_fds[i] = iSocketClient; break; } } if(i == MAX_FD){ printf("too many connections!!\n"); close(iSocketClient); continue; } } /*判断 读写套接字是否有数据 */ for(i = 1; i < MAX_FD; i++) { if((read_fds[i] != -1) && FD_ISSET(read_fds[i], &read_fd)) { iRecvLen = read(read_fds[i], ucRecvBuf, 1024); if(iRecvLen <= 0) { /* iRecvLen <0 出错 * iRecvLen=0 客户断开连接 */ if(iRecvLen == 0){ printf("disconnect from client %d\n", read_fds[i]); } close(read_fds[i]); FD_CLR(read_fds[i], &read_fd); read_fds[i] = -1; continue; } ucRecvBuf[iRecvLen] = '\0'; printf("Get Msg from client%d : %s\n", read_fds[i], ucRecvBuf); } } } close(iSocketServer); return 0; }