Linux:简单的点对点聊天(不支持多客户端连接)

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多进程下的点对点聊天

客户端:

#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>

#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#define ERR_EXIT(m)do{perror(m);exit(EXIT_FAILURE);}while(0)

void handler(int sig)
{
	printf("recv a sig=%d\n",sig);
	exit(EXIT_SUCCESS);
}


int main(void)
{
	int sock;
	if((sock = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP)) <0)
	{
		ERR_EXIT("socket");
	}
	struct sockaddr_in servaddr;
	memset(&servaddr,0,sizeof(servaddr));
	servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(5188);

    //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);
	
	if(connect(sock,(struct sockaddr*)&servaddr,sizeof(servaddr)) < 0)
	{
       ERR_EXIT("connect");
	}
	
	pid_t pid;
	pid = fork();
	if(pid == -1)
		ERR_EXIT("fork");
	if(pid == 0)
	{
		char recvbuf[1024];
		while(1)
		{
			memset(recvbuf,0,sizeof(recvbuf));
			int ret = read(sock,recvbuf,sizeof(recvbuf));
			if(ret == -1)
				ERR_EXIT("read");
			else if(ret == 0)
			{
				printf("peer close\n");
				break;
			}
			fputs(recvbuf,stdout);
		}
		close(sock);
		kill(getppid(),SIGUSR1);
	}
	else
	{
		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);
	}

    return 0;
}

服务端

#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>

#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#define ERR_EXIT(m)do{perror(m);exit(EXIT_FAILURE);}while(0)

void handler(int sig)
{
	printf("recv a sig=%d\n",sig);
	exit(EXIT_SUCCESS);
}

int main(void)
{
	int listenfd;
	if((listenfd = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP)) <0)
		//listenfd = socket(PF_INET,SOCK_STREAM,0);
	{
		ERR_EXIT("socket");
	}
	struct sockaddr_in servaddr;
	memset(&servaddr,0,sizeof(servaddr));
	servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(5188);
    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);
	
	//开启地址重复利用(在TIME_WAIT未消失的情况下,允许服务器重启)
	int on = 1;
	if(setsockopt(listenfd,SOL_SOCKET,SO_REUSEADDR,&on,sizeof(on)) < 0)
		ERR_EXIT("setsockopt");

	if(bind(listenfd,(struct sockaddr*)&servaddr,sizeof(servaddr)) < 0)
		ERR_EXIT("bind");
    
    if(listen(listenfd,SOMAXCONN) < 0)
		ERR_EXIT("listen");
	
	struct sockaddr_in peeraddr;
	socklen_t peerlen = sizeof(peeraddr);
	
	int conn;
	if((conn = accept(listenfd,(struct sockaddr*)&peeraddr, &peerlen)) < 0)
        ERR_EXIT("accept");
    printf("ip=%s port=%d\n",inet_ntoa(peeraddr.sin_addr),ntohs(peeraddr.sin_port));

	pid_t pid;
	pid = fork();
	if(pid == -1)
		ERR_EXIT("fork");
	if(pid == 0)
	{
		signal(SIGUSR1,handler);//父进程退出通知子进程退出
		char sendbuf[1024] = {0};
		while(fgets(sendbuf,sizeof(sendbuf),stdin) != NULL)
		{
			write(conn,sendbuf,sizeof(sendbuf));
			memset(sendbuf,0,sizeof(sendbuf));
		}
		printf("child close\n");
		exit(EXIT_SUCCESS);
	}
	else
	{
		char recvbuf[1024];
		while(1)
		{	
			memset(recvbuf,0,sizeof(recvbuf));
			int ret = read(conn,recvbuf,sizeof(recvbuf));
			if(ret == -1)
				ERR_EXIT("read");
			if(ret == 0)
			{
				printf("peer close\n");
				break;
			}
			fputs(recvbuf,stdout);
		}
		printf("parent close\n");
		kill(pid,SIGUSR1);
		exit(EXIT_SUCCESS);
	}
	
    return 0;
}