linux下TCP Socket编程C语言小实例

  几乎是全部按照这个链接上的网址实现的：http://blog.csdn.net/leo115/article/details/8044795

  服务器端的代码：

<span style="font-size:18px;">#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <sys/socket.h>
#include <memory.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>

//处理sighandler_t没有定义的问题
#include <signal.h>
typedef void (*sighandler_t)(int);
sighandler_t signal(int sig, sighandler_t handler);

#define PORT 11910  //定义通信的端口号
#define BACKLOG 5
#define buflen 1024 



void process_conn_server(int s);  //跟客户端进行通信的处理函数
void sig_pipe(int signo);  //信号处理函数

int ss, sc; 

int main(int argc, char *argv[])
{
	//客户端和服务器端的地址结构
	struct sockaddr_in server_addr;
	struct sockaddr_in client_addr;

	int err;
	pid_t pid;

	ss = socket(AF_INET, SOCK_STREAM, 0); //建立一个套接字，TCP
	if(ss < 0){
		printf("server: server socket create error\n");
		return -1;
	}

	//注册信号
	sighandler_t ret;
	ret =  signal(SIGTSTP, sig_pipe);
	if(SIG_ERR == ret){
		printf("signal mount error\n");
		return -1;
	}
	else
		printf("signal mount ok\n");

	//初始化地址结构
	memset(&server_addr, 0, sizeof(server_addr));
	server_addr.sin_family = AF_INET;
	server_addr.sin_addr.s_addr = htonl(INADDR_ANY); //设置地址 
	server_addr.sin_port = htons(PORT); //设置端口号

	//将套接字和地址绑定
	err = bind(ss, (struct sockaddr *)&server_addr, sizeof(struct sockaddr));
	if(err < 0){
		printf("server : bind error\n");
		return -1;
	}

	//设置监听队列的大小
	err = listen(ss, BACKLOG);
	if(err < 0){
		printf("server : listen error\n");
		return -1;
	}

	for(;;){
		socklen_t addrlen = sizeof(client_addr);
		//sc为客户端套接字描述符
		sc = accept(ss, (struct sockaddr *)&client_addr, &addrlen);
		if(sc < 0) continue;
		else printf("server : connected\n");


		pid = fork();
		if(pid == 0){ //子进程与客户端进行通信
			close(ss);
			process_conn_server(sc);
		}	
		else close(sc);  //客户端继续进行监听
	}
}

void process_conn_server(int s)
{
	ssize_t size = 0;
	char buffer[buflen];

	for(;;){
		//收到从客户端发来的数据并进行输出
		for(size = 0; size == 0; size = read(s, buffer, buflen));
		printf("%s", buffer);

		if(strcmp(buffer, "quit") == 0){
			close(s);
			return;
		}
		sprintf(buffer, "%d bytes altogether\n", size);
		write(s, buffer, strlen(buffer) + 1);
	}
}

void sig_pipe(int signo)
{
	printf("catch a signal\n");
	if(signo == SIGTSTP){
		printf("get SIGTSTP signal");
		int ret1 = close(ss);
		int ret2 = close(sc);
		int ret = ret1 > ret2 ? ret1 : ret2;
		if(ret == 0) printf("success : close IPC");
		else if(ret == -1) printf("fail : not close IPC");

		exit(1);
	}
}
</span>

  客户端程序：

<span style="font-size:18px;">#include <stdio.h>#include <strings.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <memory.h>
#include <arpa/inet.h>
#include <netinet/in.h>

#include <signal.h>
typedef void (*sighandler_t)(int);
sighandler_t signal(int sig, sighandler_t handler);

#define PORT 11910  //端口号
#define Buflen 1024

void process_conn_client(int s); //客户端进行通信的处理函数
void sig_pipe(int signo);

int s;

int main(int argc, char *argv[])
{
	struct sockaddr_in server_addr; //服务器端的地址结构
	int err;
	sighandler_t ret;

	char server_ip[50] = "";

	s = socket(AF_INET, SOCK_STREAM, 0);  //建立套接字
	if(s < 0){
		printf("client : create socket error\n");
		return 1;
	}

	ret = signal(SIGTSTP, sig_pipe);
	if(SIG_ERR == ret){
		printf("signal mount fail\n");
		return -1;
	}
	else printf("signal mount success\n");

	//初始化服务器端的地址结构
	memset(&server_addr, 0, sizeof(server_addr));
	server_addr.sin_family = AF_INET;
	server_addr.sin_port = htons(PORT);
	server_addr.sin_addr.s_addr = htonl(INADDR_ANY);

	//输入服务器的ip地址
	printf("please input server ip address: \n");
	read(0, server_ip, 50);
	server_addr.sin_addr.s_addr = inet_addr(server_ip);

	//与服务器端进行连接操作
	err = connect(s, (struct sockaddr *)&server_addr, sizeof(struct sockaddr));
	if(err == 0) printf("client : connect to server\n");
	else{
		printf("client : connect error\n");
		return -1;
	}

	process_conn_client(s);
	close(s);
}

void process_conn_client(int s)
{
	ssize_t size = 0;
	char buffer[Buflen];

	for(;;){
		memset(buffer, '\0', Buflen);
		size = read(0, buffer, Buflen);
		if(size > 0){
			write(s, buffer, strlen(buffer) + 1);
			for(size = 0; size == 0; size = read(s, buffer, Buflen));

			write(1, buffer, strlen(buffer) + 1);
		}
	}
}

void sig_pipe(int signo)
{
	printf("Catch a signal\n");
	if(signo == SIGTSTP){
		int ret = close(s);
		if(ret == 0) printf("success : close IPC\n");
		else if(ret == -1) printf("fail : not close IPC\n");
		exit(1);
	}
}</span>

  时间有点晚了，要回宿舍，写的比较草，准备明天自己实现一个，客户端输入两个整数，服务器端实现完成两个整数的加法，尝试一下...