（unix网络编程）即时通讯工具二：服务端与客户端融合

本文的聊天工具，理论上来说是没有具体区分服务端和客户端的（只针对此处的点对点聊天工具，例如QQ，微信这种IM工具是有服务器端的，要不然咋会出现服务器登不上去的故障呢？），另外服务端和客户端除了socket连线地方略有不同之外（客户端主动连接服务器，服务端被动接受连接），其他的基本都是一致的，所以服务端和客户端融合就是很有必要的了，废话不多说，具体代码如下：

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <errno.h>
#include <string.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <sys/select.h>
#include <stdlib.h>
#include <time.h>

#define MAXLINE 4096
#define ELELEN 100
#define SERV_PORT 5000
#define LISTENQ 5

struct im_msg {
	char time[ELELEN];
	char name[ELELEN];
	char data[MAXLINE];
} *imsg;

void get_cur_time(char *time_buf) {
	time_t ticks;
	char *tmp = NULL;
	char time_tmp[100];
	size_t len;
	
	memset(time_tmp, 0x00, 100);
	ticks = time(NULL);
	tmp = ctime(&ticks);
	strcat(time_tmp, "[");
	strcat(time_tmp, tmp);
	len = strlen(time_tmp);
	time_tmp[len - 1] = 0;
	strcat(time_tmp, "]");
	strcpy(time_buf, time_tmp);
}

int main(int argc, char **argv)
{
	int listenfd, connfd, maxfd;
	struct sockaddr_in cliaddr, servaddr;
	socklen_t clilen;
	char recvline[MAXLINE], sendline[MAXLINE];
	ssize_t nread;
	const char *quit_code = "quit\n";
	const char *server_name = "server: ";
	const char *client_name = "client: ";
	char msg_name[20];
	fd_set rset;

	if (argc == 1) {
		printf("#####this is im server#####\n");
		strcpy(msg_name, server_name);
	} else if (argc == 2) {
		printf("#####this is im client#####\n");
		strcpy(msg_name, client_name);
	} else {
		printf("server: ./imtool\n");
		printf("client: ./imtool <IPaddress>\n");
		return -1;
	}

	if (argc == 1) {
		if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
			perror("socket");
			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(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) {
			perror("bind");
			return -1;
		}

		if (listen(listenfd, LISTENQ) < 0) {
			perror("listen");
			return -1;
		}

		clilen = sizeof(cliaddr);
		if ((connfd = accept(listenfd, (struct sockaddr *)&cliaddr, &clilen)) < 0) {
			perror("accept");
		}

		maxfd = connfd > fileno(stdin) ? connfd + 1 : fileno(stdin) + 1; 
		imsg = (struct im_msg *)malloc(sizeof(struct im_msg));
	} else {
		if ((connfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
			perror("socket");
			return -1;
		}

		memset(&servaddr, 0x00, sizeof(servaddr));
		servaddr.sin_family = AF_INET;
		servaddr.sin_port = htons(SERV_PORT);
		if (inet_pton(AF_INET, argv[1], &servaddr.sin_addr) < 0) {
			perror("inet_pton");
			return -1;
		}

		if (connect(connfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) {
			perror("connect");
			return -1;
		}
	}

	maxfd = connfd > fileno(stdin) ? connfd + 1 : fileno(stdin) + 1;
	imsg = (struct im_msg *)malloc(sizeof(struct im_msg));

	for(;;) {
		FD_ZERO(&rset);
		FD_SET(fileno(stdin), &rset);
		FD_SET(connfd, &rset);
		memset(imsg, 0x00, sizeof(struct im_msg));
		if (select(maxfd, &rset, NULL, NULL, NULL) < 0) {
			perror("select");
			continue;
		}

		if (FD_ISSET(connfd, &rset)) {
			memset(recvline, 0x00, MAXLINE);
			nread = read(connfd, imsg, MAXLINE);
			if (nread <= 0) {
				perror("read from connfd");
				continue;
			} else {
				if (strcasecmp(imsg->data, quit_code) == 0) {
					printf("recv quit, im will exit\n");
					break;
				} else {
					strcat(recvline, imsg->time);
					strcat(recvline, imsg->name);
					strcat(recvline, imsg->data);
					if (write(fileno(stdout), recvline, sizeof(struct im_msg)) < 0) {
						perror("write to stdout");
						continue;
					}
				}
			}
		}

		if (FD_ISSET(fileno(stdin), &rset)) {
			memset(sendline, 0x00, MAXLINE);
			nread = read(fileno(stdin), imsg->data, MAXLINE);
			strcpy(imsg->name, msg_name);
			get_cur_time(imsg->time);
			if (nread < 0) {
				perror("read from stdin");
				continue;
			} else if (nread == 0) {
				printf("read EOF, server will exit\n");
				break;
			} else {
				if (strcasecmp(imsg->data, quit_code) == 0) {
					printf("input quit, im will exit\n");
					break;
				} else {
					if (write(connfd, imsg, sizeof(struct im_msg)) < 0) {
						perror("write to connfd");
						continue;
					}
				}
			}
		}
	}
	memset(imsg, 0x00, sizeof(struct im_msg));
	get_cur_time(imsg->time);
	strcpy(imsg->name, msg_name);
	strcpy(imsg->data, quit_code);
	write(connfd, imsg, sizeof(struct im_msg));
	return 0;
}