unix/linux socket 编程一，简单多进程tcp socket server流程

多进程socket server工作流程

1。创建socket句柄。

2。设置监听地址及端口号。

3。绑定到socket句柄上。

4。监听。

5。等待客户端连接。

6。创建子进程，处理客户端请求。

#include <stdio.h>#include <sys/types.h>#include <sys/stat.h>#include <sys/socket.h>#include <sys/wait.h>#include <signal.h>#include <errno.h>#include <fcntl.h>#include <string.h>#include <unistd.h>#define SERV_PORT 9999#define LISTENQ 10typedef struct sockaddr SA;typedef void Sigfunc(int);//void (* signal(int signo, void(*func)(int)))(int);//封装信号处理函数Sigfunc * signal(int signo, Sigfunc *func){struct sigaction act, oact;act.sa_handler = func;sigemptyset(&act.sa_mask);act.sa_flags = 0;if(sigaction(signo, &act, &oact) < 0)return (SIG_ERR);return(oact.sa_handler);}//处理子进程退出，子进程退出会向主进程发送SIG_CHILD信号void sig_chld(int signo){pid_t pid;int stat;while((pid = waitpid(-1, &stat, WNOHANG)) > 0)printf("child %d terminated/n", pid);return;}int main(int argc, char **argv){int fd;int readlen = 0;char sMsg[11];int listen_fd, connect_fd, clilen, childpid;struct sockaddr_in servaddr, cliaddr;printf("test sock srv/n");if((listen_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0){printf("socket error/n");return -1;}memset(&servaddr, 0x00, sizeof(servaddr));servaddr.sin_family = AF_INET;servaddr.sin_addr.s_addr = htonl(INADDR_ANY);servaddr.sin_port = htons(SERV_PORT);if(bind(listen_fd, (SA *)&servaddr, sizeof(servaddr)) < 0){printf("bind error/n");return -2;}if(listen(listen_fd, LISTENQ) < 0){printf("listen error/n");return -3;}signal(SIGCHLD, sig_chld);for(;;){clilen = sizeof(cliaddr);memset(&cliaddr, 0x00, sizeof(cliaddr));if((connect_fd = accept(listen_fd, (SA *)&cliaddr, &clilen)) < 0){ //如果accept被信号中断，则重启if(errno == EINTR || errno == ECONNABORTED)continue;else{printf("accept error/n");return -4;}}if((childpid = fork()) == 0){close(listen_fd);for(;;){memset(sMsg, 0x00, sizeof(sMsg));if( (readlen = read(connect_fd, sMsg, 10)) < 0) { close(connect_fd); printf("readn error/n");return -5;} write(fd, sMsg, readlen);}close(connect_fd);return 0;}close(connect_fd);}return 0;}