程嶏清单 17-3.txt

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程序清单17-3：server.pl
#!/usr/bin/perl
 #
 # Sample connection oriented server using Perl
 #
 $AF_UNIX = 1;
 $AF_INET=2;     # Use AF_INET instead of AF_UNIX.
 $SOCK_STR = 1;  # Use STREAMS.
 $PROTOCOL = 0;  # stick to the default protocols (IP).

 $port = 6668 unless $port;

 #
 # The pattern for packing into a sockaddr structure
 #
 $PACKIT='S n C4 x8';

 #
 # Disable any buffering on any newly created sockets.
 #
 select(NEWSOCKET);
 $| = 1;
 select(stdout);

 #
 # Create the socket.
 #
 socket(MY_SOCKET, $AF_INET, $SOCK_STR, $PROTOCOL) ||
                        die "\n $0: Cannot open socket: $!";
 print "Socket successfully opened\n";

 #
 # Get the host address for this node
 #

 ($name, $aliases, $addrtype, $len, @addrs) = gethostbyname("www.ikra.com"); 
 ($a,$b,$c,$d) = unpack('C4',$addrs[0]);
 print "Server Name=$name, Server Address= $a.$b.$c.$d\n"; 
 $my_ip_addr = pack($PACKIT,$AF_INET,$port,$addrs[0]);

 #
 # If you just want to test with the localhost, try this line 
 # instead of the above.
 # $my_ip_addr = pack($PACKIT,$AF_INET,$port,127,0,0,1);

 #
 # Bind to the socket and listen on this port
 #
 bind(MY_SOCKET, $my_ip_addr) || die "$0: Cannot bind .. $!\n";
 print  "\n Bound to socket";
 listen(MY_SOCKET,5)  || die "$0: Cannot listen: $!\n";
 print  "\n Listening \n";

 while(1) {
      $remote = accept(NEWSOCKET, MY_SOCKET) || die "$0: Unacceptable: $!\n";

 #
 # In case you have to display incoming connection
 # information, you can uncomment the next three lines of code: 

 #         @remoteInfo = unpack($PACKIT,$remote);
 #         $, = ' ';
 #         print @remoteInfo; print "\n";

      # $pid = fork || &cleanup; 

           if ($pid == fork)  {  # child
           sleep 3;
           print NEWSOCKET "Welcome to this server\n";
           # in child,.. you can do other stuff here.
           close NEWSOCKET;
           # I chose to just print this message and terminate
           close MY_SOCKET;
           exit;
      }
      else {  # parent s
           sleep 10;
           close MY_SOCKET;
           close NEWSOCKET;  # in parent
           exit;
      }

 }
 sub cleanup { close NEWSOCKET; close(MY_SOCKET); die "$0: Cannot fork : $!\n"; }