#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<sys/socket.h>
#include<fcntl.h>
#include<errno.h>
#include<pthread.h>
#define BUF_SIZE 100
#define MAX_CLNT 256
void * handle_clnt(void * arg);
void send_msg(char * msg, int len);
void error_handling(char * msg);
int clnt_cnt = 0;
int clnt_socks[MAX_CLNT];
pthread_mutex_t mutex;
int main(int argc, char *argv[])
{
//用来管理接入的客户端套接字的变量和数组。访问这两个变量的代码将构成临界区
int serv_sock, clnt_sock;
struct sockaddr_in serv_adr, clnt_adr;
int clnt_adr_sz;
pthread_t t_id;
if(argc != 2){
printf("Usage : %s <port> \n", argv[0]);
exit(1);
}
pthread_mutex_init(&mutex, NULL);
serv_sock = socket(PF_INET, SOCK_STREAM, 0);
memset(&serv_adr, 0, sizeof(serv_adr));
serv_adr.sin_family = AF_INET;
serv_adr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_adr.sin_port = htons(atoi(argv[1]));
if(bind(serv_sock, (struct sockaddr *) &serv_adr, sizeof(serv_adr)) == -1)
error_handling("bind() error");
if(listen(serv_sock, 5) == -1)
error_handling("listen() error");
while(1)
{
clnt_adr_sz = sizeof(clnt_adr);
clnt_sock = accept(serv_sock, (struct sockaddr *)&clnt_adr, &clnt_adr_sz);
pthread_mutex_lock(&mutex);
//每当有新的连接时，将相关信息写入变量clnt_cnt和clnt_socks
clnt_socks[clnt_cnt++] = clnt_sock;
pthread_mutex_unlock(&mutex);
//创建线程向新连入的客户端提供服务
pthread_create(&t_id, NULL, handle_clnt, (void*)&clnt_sock);
//调用pthread_detach函数从内存中完全销毁已终止的线程
pthread_detach(t_id);
printf("Connected client IP: %s \n", inet_ntoa(clnt_adr.sin_addr));
}
close(serv_sock);
return 0;
}
void * handle_clnt(void * arg)
{
int clnt_sock = *((int*)arg);
int str_len = 0, i;
char msg[BUF_SIZE];
while((str_len = read(clnt_sock, msg, sizeof(msg))) != 0)
send_msg(msg, str_len);
pthread_mutex_lock(&mutex);
for(i = 0; i < clnt_cnt; i++) //remove disconnected client
{
if(clnt_sock == clnt_socks[i])
{
while(i++ < clnt_cnt - 1)
clnt_socks[i] = clnt_socks[i + 1];
break;
}
}
clnt_cnt--;
pthread_mutex_unlock(&mutex);
close(clnt_sock);
return NULL;
}
//该函数负责向所有客户端发送消息
void send_msg(char *msg, int len) // send to all
{
int i;
pthread_mutex_lock(&mutex);
for(i = 0; i < clnt_cnt; i++)
write(clnt_socks[i], msg, len);
pthread_mutex_unlock(&mutex);
}
void error_handling(char *msg)
{
fputs(msg, stderr);
fputc('\n', stderr);
exit(1);
}
