[cs631apue] Forking too many processes.

[lbustama]

By the way here is part of the code. Just in case I'm doing something 
wrong:

listen(sock, 5);
184     do {
185         FD_ZERO(&ready);
186         FD_SET(sock, &ready);
187         to.tv_sec = 5;
188         to.tv_usec = 0;
189         if (select(sock + 1, &ready, 0, 0, &to) < 0) {
190             perror("select");
191             continue;
192         }
193         if (FD_ISSET(sock, &ready)) {
194
195             pid_t pid;
196             if((pid = fork()) < 0)
197             {
199                 perror("fork error");
200             }
201             if(pid == 0) /*child*/
202             {
203                 /* variables for client information */
204                 socklen_t client_length;
205                 struct sockaddr_in client;
206                 unsigned int client_port;
207
208                 client_length = sizeof(client);
209                 msgsock = accept(sock, (struct sockaddr *)&client,
210                         &client_length);
                     ....
230                 exit(EXIT_SUCCESS);
231             }
232             else
233             {
234                 printf("forked pid: %d\n",pid);
235             }
236         }
243     } while (TRUE);

Thanks,

Luis

On 11/04/2013 2:43 PM, lbustama wrote:
> Hi,
> 
> When a new connection comes in to the server I fork a new process to
> take care of the new connection.
> 
> I was having an issue after forking the new process.
> The problem was that before the child process was able to
> "accept(...)" the connection the parent process forks another process
> as the connection is still in the queue.
> 
> macbookpro:HW3$ ./sws &
> [2] 6832
> 
> macbookpro:HW3$ Server listening on IP address 0.0.0.0 and port# 8080
> forked pid: 6834
> 127.0.0.1#62858: Connected:
> forked pid: 6835
> 
> macbookpro:HW3 Luis$ !net
> netstat -na | grep 8080
> tcp4       0      0  127.0.0.1.8080         127.0.0.1.62858        
> ESTABLISHED
> tcp4       0      0  127.0.0.1.62858        127.0.0.1.8080         
> ESTABLISHED
> tcp4       0      0  *.8080                 *.*                    
> LISTEN
> macbookpro:HW3 Luis$
> 
> ^^^ 1 active connection
> 
> macbookpro:HW3$ ps -o pid,ppid,comm | grep sws
>  6832  6556 ./sws
>  6834  6832 ./sws
>  6835  6832 ./sws
> 
> 
> 
> ^^^ 2 new processes for 1 request
> 
> 
> The way I got around this was to put the parent process to sleep for 1
> second, which will allow the child to grab the new connection.
> 
> I was wondering if there is a better way to do this? what if your web
> server receives several connections per second. Only 1 connection is
> handled every second, which is obviously not good.
> 
> Thanks,
> 
> Luis