HP Rp7410 BSD Sockets Interface Programmer's Guide - Page 170

Programming Hints Adding a Server Process to the Internet Daemon * M A I N * * This is the actual server routine that the /etc/inetd forks to * handle each individual connection. Its purpose is to receive * the request packets from the remote client, process them, * and return the results to the client. * */ main() { char buf[10]; /* This example uses 10 byte messages. */ int len, lenl; /* Go into a loop, receiving requests from the remote * client. After the client has sent the last request, * it will do a shutdown for sending, which will cause * an end-of-file condition to appear on this end of the * connection. After all the client's requests have * been received, the next recv call will return zero * bytes, signaling an end-of-file condition. This is * how the server will know that no more requests will * follow, and the loop will be exited. */ while (len = recv(0, buf, 10, 0)) { if (len == -1) { exit (1); /* error from recv */ } /* The reason this while loop exists is that there * is a remote possibility of the above recv returning * less than 10 bytes. This is because a recv returns * as soon as there is some data, and will not wait for * all of the requested data to arrive. Since 10 bytes * is relatively small compared to the allowed TCP * packet sizes, a partial receive is unlikely. If * this example had used 2048 bytes requests instead, * a partial receive would be far more likely. * This loop will keep receiving until all 10 bytes * have been received, thus guaranteeing that the * next recv at the top of the loop will start at the * beginning of the next request. */ while (len < 10) { len1 = recv(0, &buf[len], 10-len, 0); if (len1 == -1) { exit (1); } len += len1; } /* This sleep simulates the processing of * the request that a real server may do. */ sleep(1); /* Send a response back to the client. */ if (send(0, buf, 10, 0) != 10) { exit (1); } } } /* The loop has terminated, because there are no * more requests to be serviced. 170 Chapter 8