Shulou(Shulou.com)06/02 Report--

Preface

This chapter is to write a complete server and client example with basic Linux basic functions plus epoll calls, which can be run on Linux. The client and server functions are as follows:

The client reads a line from the standard input, sends it to the server, reads a line from the network, then outputs it to the client, receives the response from the server, and outputs this line to the standard output.

Server side

The code is as follows:

# include # include / * basic system data types * / # include / * basic socket definitions * / # include / * sockaddr_in {} and other Internet defns * / # include / * inet (3) functions * / # include / * epoll function * / # include / * nonblocking * / # include / * setrlimit * / # include # define MAXEPOLLSIZE 10000#define MAXLINE 10240int handle (int connfd) Int setnonblocking (int sockfd) {if (fcntl (sockfd, F_SETFL, fcntl (sockfd, F_GETFD, 0) | O_NONBLOCK) =-1) {return-1;} return 0;} int main (int argc, char * * argv) {int servPort = 6888; int listenq = 1024; int listenfd, connfd, kdpfd, nfds, n, nread, curfds,acceptCount = 0; struct sockaddr_in servaddr, cliaddr; socklen_t socklen = sizeof (struct sockaddr_in); struct epoll_event ev Struct epoll_event events [MAXEPOLLSIZE]; struct rlimit rt; char buf [MAXLINE]; / * set the maximum number of files allowed per process * / rt.rlim_max = rt.rlim_cur = MAXEPOLLSIZE; if (setrlimit (RLIMIT_NOFILE, & rt) = =-1) {perror ("setrlimit error"); return-1;} bzero (& servaddr, sizeof (servaddr)); servaddr.sin_family = AF_INET Servaddr.sin_addr.s_addr = htonl (INADDR_ANY); servaddr.sin_port = htons (servPort); listenfd = socket (AF_INET, SOCK_STREAM, 0); if (listenfd =-1) {perror ("can't create socket file"); return-1;} int opt = 1; setsockopt (listenfd, SOL_SOCKET, SO_REUSEADDR, & opt, sizeof (opt); if (setnonblocking (listenfd))

< 0) { perror("setnonblock error"); } if (bind(listenfd, (struct sockaddr *) &servaddr, sizeof(struct sockaddr)) == -1) { perror("bind error"); return -1; } if (listen(listenfd, listenq) == -1) { perror("listen error"); return -1; } /* 创建 epoll 句柄，把监听 socket 加入到 epoll 集合里 */ kdpfd = epoll_create(MAXEPOLLSIZE); ev.events = EPOLLIN | EPOLLET; ev.data.fd = listenfd; if (epoll_ctl(kdpfd, EPOLL_CTL_ADD, listenfd, &ev) < 0) { fprintf(stderr, "epoll set insertion error: fd=%d\n", listenfd); return -1; } curfds = 1; printf("epollserver startup,port %d, max connection is %d, backlog is %d\n", servPort, MAXEPOLLSIZE, listenq); for (;;) { /* 等待有事件发生 */ nfds = epoll_wait(kdpfd, events, curfds, -1); if (nfds == -1) { perror("epoll_wait"); continue; } /* 处理所有事件 */ for (n = 0; n < nfds; ++n) { if (events[n].data.fd == listenfd) { connfd = accept(listenfd, (struct sockaddr *)&cliaddr,&socklen); if (connfd < 0) { perror("accept error"); continue; } sprintf(buf, "accept form %s:%d\n", inet_ntoa(cliaddr.sin_addr), cliaddr.sin_port); printf("%d:%s", ++acceptCount, buf); if (curfds >

= MAXEPOLLSIZE) {fprintf (stderr, "too many connection, more than% d\ n", MAXEPOLLSIZE); close (connfd); continue;} if (setnonblocking (connfd) < 0) {perror ("setnonblocking error");} ev.events = EPOLLIN | EPOLLET; ev.data.fd = connfd If (epoll_ctl (kdpfd, EPOLL_CTL_ADD, connfd, & ev) < 0) {fprintf (stderr, "add socket'% d'to epoll failed:% s\ n", connfd, strerror (errno)); return-1;} curfds++; continue } / / process client request if (handle (events [n] .data.fd) < 0) {epoll_ctl (kdpfd, EPOLL_CTL_DEL, events [n] .data.fd, & ev); curfds--;}} close (listenfd); return 0;} int handle (int connfd) {int nread; char buf [MAXLINE]; nread = read (connfd, buf, MAXLINE) / / read client socket stream if (nread = = 0) {printf ("client close the connection\ n"); close (connfd); return-1;} if (nread < 0) {perror ("read error"); close (connfd); return-1;} write (connfd, buf, nread); / / response client return 0;}

Compile

Compile and start the server

Gcc epollserver.c-o epollserver./epollserver

Summary

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