0x04基础套接字-简单聊天程序实现

聊天程序实现

• 用多进程方式实现点对点聊天
  • 一个进程用来获得输入，一个进程用来获得对方发来的消息

客户端

//p2pcli.c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>

void handler(int sig)
{
	exit(EXIT_SUCCESS);
}

int main()
{
	int sock;
	//创建一个套接字
	if((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0){
		perror("Creat socket failed.");
		exit(1);
	}
	/*int socket(int domain, int type, int protocol);*/
	struct sockaddr_in servaddr;
	memset(&servaddr, 0, sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_port = htons(9000);
	servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
	/*servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");*/
	/*inet_aton("127.0.0.1", &servaddr.sin_addr);*/
	if(connect(sock, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0){
		perror("connect() error");
		exit(1);
	}
	
	//
	
	pid_t pid;
	pid = fork();
	if(pid == -1){
		perror("fork() error");
	}
	if(pid == 0){
		//子进程接收对方发送的数据
		char recvbuf[1024] = {0};
		while(1){
			memset(recvbuf, 0, sizeof(recvbuf));
			int ret = read(sock, recvbuf, sizeof(recvbuf));
			if(ret == -1){
				perror("read() error");
				exit(1);
			} else if(ret == 0){
				printf("peer close\n");
				break;
			}
			fputs(recvbuf, stdout);
		}
		close(sock);
		kill(getppid(), SIGUSR1);//通知父进程退出
		exit(EXIT_SUCCESS);
	} else {
		//主进程发送数据

		signal(SIGUSR1, handler);
		char sendbuf[1024] = {0};
		while(fgets(sendbuf, sizeof(sendbuf), stdin) != NULL){
			write(sock, sendbuf, strlen(sendbuf));
			memset(sendbuf, 0, sizeof(sendbuf));
		}
		close(sock);
		exit(EXIT_SUCCESS);
	}

	return 0;
}

服务器端

//p2pserv.c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>

void handler(int sig)
{
	exit(EXIT_SUCCESS);
}

int main()
{
	int listenfd;
	//创建一个套接字
	if((listenfd = socket(AF_INET, SOCK_STREAM, 0)) < 0){
		perror("Create socket failed.");
		exit(1);
	}
	/*int socket(int domain, int type, int protocol);*/
	struct sockaddr_in servaddr;
	memset(&servaddr, 0, sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_port = htons(9000);
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
	/*servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");*/
	/*inet_aton("127.0.0.1", &servaddr.sin_addr);*/
	int on = 1;//选项开启标志
	//设置地址重复利用
	if(setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0){
		perror("setsockopt error.");
		exit(1);
	}

	if(bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0){
		perror("bind error.");
		exit(1);
	}
	//绑定
	if(listen(listenfd, SOMAXCONN) < 0){
		perror("listen() error.");
		exit(1);
	}
	//监听
	
	struct sockaddr_in peeraddr;
	socklen_t peerlen = sizeof(peeraddr);
	int conn;
	if((conn = accept(listenfd, (struct sockaddr*)&peeraddr, &peerlen)) < 0){
		perror("accept() error");
		exit(1);
	}
	printf("ip = %s, port = %d\n", inet_ntoa(peeraddr.sin_addr), ntohs(peeraddr.sin_port));
	//
	pid_t pid;
	pid = fork();
	if(pid == -1){
		perror("fork() error");
		exit(1);
	}
	if(pid == 0){
		//发送数据的子进程

		signal(SIGUSR1, handler);
		char sendbuf[1024] = {0};
		while(fgets(sendbuf, sizeof(sendbuf), stdin) != NULL){
			write(conn, sendbuf, strlen(sendbuf));
			memset(sendbuf, 0, sizeof(sendbuf));
		}
		exit(EXIT_SUCCESS);
	} else {
		//父进程用于获取对方发送的数据
		char recvbuf[1024];
		while (1){
			memset(recvbuf, 0, sizeof(recvbuf));
			int ret = read(conn, recvbuf, sizeof(recvbuf));
			 if(ret == -1){
				perror("read error");
				exit(1);
			} else if(ret == 0){
				printf("peer close\n");
				break;
			}
			fputs (recvbuf, stdout);
		}
		kill(pid, SIGUSR1);//通知子进程退出
		exit(EXIT_SUCCESS);
	}
	return 0;
}

实验结果