epoll機制

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
#include <sys/epoll.h>

int client(int connfd)
{
	int ret;
	char buf[256];
	memset(buf, 0, sizeof(buf));
	ret = read(connfd, buf, sizeof(buf));
	if (ret == -1) {
		perror("server->read");
		return -1;
	} else if (ret == 0) {
		return -1;
	}

	printf("buf : %s\n", buf);
	ret = write(connfd, buf, sizeof(buf));
	if (ret == -1) {
		perror("server->write");
		return -1;
	}
	return 0;
}

int main(int argc, char *argv[])
{
	int listenfd;
	int ret;
	socklen_t addrlen;
	int connfd;
	pid_t pid;
	char buf[256];
	struct sockaddr_in srvaddr;
	struct sockaddr_in cltaddr;

	/* 1. 創建服務器（創建一socket套接字）；socket */
	listenfd = socket(AF_INET, SOCK_STREAM, 0);
	if (listenfd == -1) {
		perror("server->socket");
		return -1;
	}
	printf("create listenfd = %d success\n", listenfd);

	int opt = 1;
	setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));

	/* 2. 設置服務器的IP地址和端口號（將socket和服務器的IP地址和端口號進行綁定）；bind */
	memset(&srvaddr, 0, sizeof(struct sockaddr_in));
	srvaddr.sin_family = AF_INET;
	srvaddr.sin_port = htons(9999);
	srvaddr.sin_addr.s_addr = htonl(INADDR_ANY);
	ret = bind(listenfd, (const struct sockaddr *)&srvaddr, sizeof(srvaddr));

	printf("port : %d\n", ntohs(srvaddr.sin_port));
	if (ret == -1) {
		perror("server->bind");
		return -1;
	}
	printf("bind success !\n");

	/* 3. 啓動監聽（啓動服務器）；  listen */
	ret = listen(listenfd, 1024);
	if (ret == -1) {
		perror("server->listen");
		return -1;
	}
	printf("listen success !\n");

	/* 創建集合；*/
	int epfd;
	int i;
	int fd;

	epfd = epoll_create(1024);
	if (epfd == -1) {
		perror("epoll_create");
		return -1;
	}
	printf("epfd = %d\n", epfd);

	/* 添加所需要處理的事件和文件描述符 */
	struct epoll_event event;
	event.events = EPOLLIN;
	event.data.fd = listenfd;
	ret = epoll_ctl(epfd, EPOLL_CTL_ADD, listenfd, &event);
	if (ret == -1) {
		perror("epoll_ctl->EPOLL_CTL_ADD");
		return -1;
	}

	struct epoll_event events[1024];
	while(1) {
		/* 檢測集合當中是否有繼續的文件描述符 */
		ret = epoll_wait(epfd, events, 1024, 5000);
		if (ret == -1) {
			perror("poll");
			return -1;
		} else if (ret == 0) {
			printf("timeout\n");
			continue;
		}

		/* 輪循 */
		for (i = 0; i < ret; i++) {
			/* 判斷是什麼事件  */
			if (EPOLLIN == events[i].events) {
				fd = events[i].data.fd;
				/* 如果是監聽套接字listenfd，則建立連接 */
				if (fd == listenfd) {
					memset(&cltaddr, 0, sizeof(cltaddr));
					addrlen = sizeof(socklen_t);
					connfd = accept(listenfd, (struct sockaddr *)&cltaddr, &addrlen);
					if (connfd == -1) {
						perror("accept");
						return -1;
					}

					printf("connfd = %d\n", connfd);
					event.events = EPOLLIN;
					event.data.fd = connfd;
					ret = epoll_ctl(epfd, EPOLL_CTL_ADD, connfd, &event);
					if (ret == -1) {
						perror("epoll_ctl->EPOLL_CTL_ADD");
						return -1;
					}
				} else {
					ret = client(fd);
					if (ret == -1) {
						ret = epoll_ctl(epfd, EPOLL_CTL_DEL, fd, &event);
						if (ret == -1) {
							perror("epoll_ctl->EPOLL_CTL_DEL");
							return -1;
						}
						close(fd);
					}
				}
			}
		}
	}
	close(epfd);
	close(listenfd);

	return 0;
}