所以这是我的问题,我有一个服务器在客户端连接时调用此代码,问题是,一旦客户端调用,它就会进入无限循环,我不知道为什么。我希望代码在 Select 上再次等待另一个客户端连接,但是,初始触发器继续导致永无止境的循环。
当一个客户端连接时输出:
Lets startYOOHELLO WORLD WE MATCH
Lets startYOOHELLO WORLD WE MATCH
...
.
.
.
..
所以这是我的问题,我有一个服务器在客户端连接时调用此代码,问题是,一旦客户端调用,它就会进入无限循环,我不知道为什么。我希望代码在 Select 上再次等待另一个客户端连接,但是,初始触发器继续导致永无止境的循环。
当一个客户端连接时输出:
Lets startYOOHELLO WORLD WE MATCH
Lets startYOOHELLO WORLD WE MATCH
...
.
.
.
..
如果您的服务器只想接受连接,那么您应该只选择原始套接字 FD。您不应该从接受中选择新的 FD。
您陷入无限循环的原因是因为you are not accepting new connections from the clients
在您的无限循环和结构数组中的文件/套接字描述符中,are not valid any more
因为这些客户端已经终止。您选择了一种非常差的使用 select 的机制。
你应该这样做:
while(1)
{
FD_ZERO(&readfds);
//add master socket to set
FD_SET(master_socket, &readfds);
max_sd = master_socket;
//add child sockets to set
for ( i = 0 ; i < max_clients ; i++)
{
//socket descriptor
sd = client_socket[i];
//if valid socket descriptor then add to read list
if(sd > 0)
FD_SET( sd , &readfds);
//highest file descriptor number, need it for the select function
if(sd > max_sd)
max_sd = sd;
}
//wait for an activity on one of the sockets , timeout is NULL , so wait indefinitely
activity = select( max_sd + 1 , &readfds , NULL , NULL , NULL);
if ((activity < 0) && (errno!=EINTR))
{
printf("select error");
}
//If something happened on the master socket , then its an incoming connection
if (FD_ISSET(master_socket, &readfds))
{
if ((new_socket = accept(master_socket, (struct sockaddr *)&address, (socklen_t*)&addrlen))<0)
{
perror("accept");
exit(EXIT_FAILURE);
}
//inform user of socket number - used in send and receive commands
printf("New connection , socket fd is %d , ip is : %s , port : %d \n" , new_socket , inet_ntoa(address.sin_addr) , ntohs(address.sin_port));
//send new connection greeting message
if( send(new_socket, message, strlen(message), 0) != strlen(message) )
{
perror("send");
}
puts("Welcome message sent successfully");
//add new socket to array of sockets
for (i = 0; i < max_clients; i++)
{
//if position is empty
if( client_socket[i] == 0 )
{
client_socket[i] = new_socket;
printf("Adding to list of sockets as %d\n" , i);
break;
}
}
}
//else its some IO operation on some other socket :)
for (i = 0; i < max_clients; i++)
{
sd = client_socket[i];
if (FD_ISSET( sd , &readfds))
{
//Check if it was for closing , and also read the incoming message
if ((valread = read( sd , buffer, 1024)) == 0)
{
//Somebody disconnected , get his details and print
getpeername(sd , (struct sockaddr*)&address , (socklen_t*)&addrlen);
printf("Host disconnected , ip %s , port %d \n" , inet_ntoa(address.sin_addr) , ntohs(address.sin_port));
//Close the socket and mark as 0 in list for reuse
close( sd );
client_socket[i] = 0;
}
//Echo back the message that came in
else
{
//set the string terminating NULL byte on the end of the data read
buffer[valread] = '\0';
send(sd , buffer , strlen(buffer) , 0 );
}
}
}
}
return 0;
}