poll機制

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
#include <poll.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) {
		close(connfd);
		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);

	/* 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 = inet_addr("192.168.2.100");
	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，並且將集合當中的每一個數組元素的fd成員賦值爲-1；*/
	int nfds;
	int fd;
	int i;
	int j;
	struct pollfd fds[1024];
	for (i = 0; i < 1024; i++) {
		fds[i].fd = -1;
	}

	/* 添加所需要處理的事件和文件描述符 */
	fds[0].fd = listenfd;
	fds[0].events = POLLIN;
	nfds = listenfd+1;

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

		/* 輪循 */
		for (i = 0; i < nfds; i++) {
			/* 判斷是什麼事件  */
			if (POLLIN == fds[i].revents) {
				/* 判斷，尋找就緒的文件描述符 */
				if (fds[i].fd != -1) {
					fd = fds[i].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);
						for (j = 0; j < 1024; j++) {
							if (fds[j].fd != -1) {
								continue;
							}
							fds[j].fd = connfd;
							fds[j].events = POLLIN;
#if 0
							if (nfds <= connfd) {
								nfds = connfd + 1;				
							}
#endif
							nfds = nfds <= connfd ? connfd+1 : nfds;
							break;
						}
					} else {
						ret = client(fd);
						if (ret == -1) {
							fds[i].fd = -1;
						}
					}
				}
			}
		}
	}
	close(listenfd);

	return 0;
}