[LON-CAPA-cvs] cvs: loncom / lonc

foxr lon-capa-cvs@mail.lon-capa.org
Thu, 04 Apr 2002 21:55:55 -0000


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foxr		Thu Apr  4 16:55:55 2002 EDT

  Modified files:              
    /loncom	lonc 
  Log:
  Use single fully blocking select for input, output and connection requests.
  
  
  
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Index: loncom/lonc
diff -u loncom/lonc:1.36 loncom/lonc:1.37
--- loncom/lonc:1.36	Tue Mar 26 23:07:02 2002
+++ loncom/lonc	Thu Apr  4 16:55:55 2002
@@ -5,7 +5,7 @@
 # provides persistent TCP connections to the other servers in the network
 # through multiplexed domain sockets
 #
-# $Id: lonc,v 1.36 2002/03/27 04:07:02 foxr Exp $
+# $Id: lonc,v 1.37 2002/04/04 21:55:55 foxr Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -315,120 +315,65 @@
 %outbuffer = ();
 %ready     = ();
 %servers   = ();	# To be compatible with make filevector.  indexed by
-			# File descriptors, values are file descriptors.
+			# File ids, values are sockets.
 			# note that the accept socket is omitted.
 
 tie %ready, 'Tie::RefHash';
 
-nonblock($server);
-$select = IO::Select->new($server);
+# nonblock($server);
+# $select = IO::Select->new($server);
 
 # Main loop: check reads/accepts, check writes, check ready to process
+
+status("Main loop");
 while (1) {
     my $client;
     my $rv;
     my $data;
 
     my $infdset;		# bit vec of fd's to select on input.
-    my $inreadyset;		# Bit vec of fd's ready for input.
 
     my $outfdset;		# Bit vec of fd's to select on output.
-    my $outreadyset;		# bit vec of fds ready for output.
 
 
     $infdset = MakeFileVector(\%servers);
     $outfdset= MakeFileVector(\%outbuffer);
-
-    # check for new information on the connections we have
-    # anything to read or accept?
-
-    foreach $client ($select->can_read(00.10)) {
-        if ($client == $server) {
-            # accept a new connection
-            &status("Accept new connection: $conserver");
-            $client = $server->accept();
-            $select->add($client);
-            nonblock($client);
-        } else {
-            # read data
-            $data = '';
-            $rv   = $client->recv($data, POSIX::BUFSIZ, 0);
-
-            unless (defined($rv) && length $data) {
-                # This would be the end of file, so close the client
-                delete $inbuffer{$client};
-                delete $outbuffer{$client};
-                delete $ready{$client};
-
-                &status("Idle");
-                $select->remove($client);
-                close $client;
-                next;
-            }
-
-            $inbuffer{$client} .= $data;
-
-
-            # test whether the data in the buffer or the data we
-            # just read means there is a complete request waiting
-            # to be fulfilled.  If there is, set $ready{$client}
-            # to the requests waiting to be fulfilled.
-            while ($inbuffer{$client} =~ s/(.*\n)//) {
-                push( @{$ready{$client}}, $1 );
-            }
-        }
+    vec($infdset, $server->fileno, 1) = 1;
+    if($DEBUG) {
+	&logthis("Adding ".$server->fileno.
+		 " to input select vector (listner)".
+		 unpack("b*",$infdset)."\n");
     }
-    
-    # Any complete requests to process?
-    foreach $client (keys %ready) {
-        handle($client);
+    DoSelect(\$infdset, \$outfdset); # Wait for input.
+    if($DEBUG) {
+	&logthis("Doselect completed!");
+	&logthis("ins = ".unpack("b*",$infdset)."\n");
+	&logthis("outs= ".unpack("b*",$outfdset)."\n");
+		 
     }
- 
-    # Buffers to flush?
-    foreach $client ($select->can_write(1)) {
-        # Skip this client if we have nothing to say
-        next unless exists $outbuffer{$client};
-
-        $rv = $client->send($outbuffer{$client}, 0);
-
-      unless ($outbuffer{$client} eq "con_lost\n") {
-        unless (defined $rv) {
-            # Whine, but move on.
-            &logthis("I was told I could write, but I can't.\n");
-            next;
-        }
-        $errno=$!;
-        if (($rv == length $outbuffer{$client}) ||
-            ($errno == POSIX::EWOULDBLOCK) || ($errno == 0)) {
-            substr($outbuffer{$client}, 0, $rv) = '';
-            delete $outbuffer{$client} unless length $outbuffer{$client};
-        } else {
-            # Couldn't write all the data, and it wasn't because
-            # it would have blocked.  Shutdown and move on.
-
-	    &logthis("Dropping data with ".$errno.": ".
-                     length($outbuffer{$client}).", $rv");
 
-            delete $inbuffer{$client};
-            delete $outbuffer{$client};
-            delete $ready{$client};
-
-            $select->remove($client);
-            close($client);
-            next;
-        }
-      } else {
-# -------------------------------------------------------- Wow, connection lost
-         &logthis(
-     "<font color=red>CRITICAL: Closing connection</font>");
-	 &status("Connection lost");
-         $remotesock->shutdown(2);
-         &logthis("Attempting to open new connection");
-         &openremote($conserver);          
-      }
+    # Checkfor new connections:
+    if (vec($infdset, $server->fileno, 1)) {
+	if($DEBUG) {
+	    &logthis("New connection established");
+	}
+	# accept a new connection
+	&status("Accept new connection: $conserver");
+	$client = $server->accept();
+	if($DEBUG) {
+	    &logthis("New client fd = ".$client->fileno."\n");
+	}
+	$servers{$client->fileno} = $client;
+	nonblock($client);
     }
-   
+    HandleInput($infdset, \%servers, \%inbuffer, \%outbuffer, \%ready);
+    HandleOutput($outfdset, \%servers, \%outbuffer, \%inbuffer,
+		 \%ready);
+# -------------------------------------------------------- Wow, connection lost
+
 }
+   
+    }
 }
 
 # ------------------------------------------------------- End of make_new_child
@@ -446,8 +391,12 @@
     my $fdhash = shift;
     my $selvar = "";
 
-    foreach $socket (keys %fdhash) {
-	vec($selvar, ($fdhash->{$socket})->fileno, 1) = 1;
+    foreach $socket (keys %$fdhash) {
+	if($DEBUG) {
+	    &logthis("Adding  ".$socket.
+		     "to select vector. (client)\n");
+	}
+	vec($selvar, $socket, 1) = 1;
     }
     return $selvar;
 }
@@ -458,7 +407,7 @@
 #    Processes output on a buffered set of file descriptors which are
 #    ready to be read.
 #  Parameters:
-#    $selvector - Vector of writable file descriptors which are writable.
+#    $selvector - Vector of file descriptors which are writable.
 #    \%sockets  - Vector of socket references indexed by socket.
 #    \%buffers  - Reference to a hash containing output buffers.
 #                 Hashes are indexed by sockets.  The file descriptors of some
@@ -477,11 +426,19 @@
     my $buffers   = shift;
     my $inbufs    = shift;
     my $readys    = shift;
+    my $sock;
 
-    foreach $sock (keys %buffers) {
+    if($DEBUG) {
+	&logthis("HandleOutput entered\n");
+    }
+
+    foreach $sock (keys %$sockets) {
 	my $socket = $sockets->{$sock};
-	if(vec($selvector, $$socket->fileno, 1)) { # $socket is writable.
-	    my $rv = $$socket->send($buffers->{$sock}, 0);
+	if(vec($selvector, $sock, 1)) { # $socket is writable.
+	    if($DEBUG) {
+		&logthis("Sending $buffers->{$sock} \n");
+	    }
+	    my $rv = $socket->send($buffers->{$sock}, 0);
 	    $errno = $!;
 	    unless ($buffers->{$sock} eq "con_lost\n") {
 		unless (defined $rv) { # Write failed... could be EINTR
@@ -510,7 +467,7 @@
 		    delete $inbufs->{$sock};
 		    delete $readys->{$sock};
 
-		    close($$socket); # Close the client socket.
+		    close($socket); # Close the client socket.
 		    next;
 		}
 	    } else {		# Kludgy way to mark lond connection lost.
@@ -519,7 +476,7 @@
 		status("Connection lost");
 		$remotesock->shutdown(2);
 		&logthis("Attempting to open a new connection");
-		&openremot($conserver);
+		&openremote($conserver);
 	    }
 		   
 	}
@@ -553,14 +510,19 @@
     my $ibufs   = shift;
     my $obufs   = shift;
     my $ready   = shift;
+    my $sock;
 
-    foreach $sock (keys %sockets) {
+    &logthis("Entered HandleInput\n");
+    foreach $sock (keys %$sockets) {
 	my $socket = $sockets->{$sock};
-	if(vec($selvec, $$socket->fileno, 1)) { # Socket which is readable.
+	if(vec($selvec, $sock, 1)) { # Socket which is readable.
 
 	    #  Attempt to read the data and do error management.
 	    my $data = '';
-	    my $rv = $$socket->recv($data, POSIX::BUFSIZ, 0);
+	    my $rv = $socket->recv($data, POSIX::BUFSIZ, 0);
+	    if($DEBUG) {
+		&logthis("Received $data from socket");
+	    }
 	    unless (defined($rv) && length $data) {
 
 		# Read an end of file.. this is a disconnect from the peer.
@@ -571,7 +533,7 @@
 		delete $ready->{$sock};
 
 		status("Idle");
-		close $$socket;
+		close $socket;
 		next;
 	    }
 	    #  Append the read data to the input buffer. If the buffer
@@ -611,12 +573,22 @@
     my $ins;
 
     while (1) {
-	my $nfds = select($outs = $$writevec, $ins = $$readvec, undef, undef);
-	if($nfound) {
+	my $nfds = select( $ins = $$readvec, $outs = $$writevec, undef, undef);
+	if($nfds) {
+	    if($DEBUG) {
+		&logthis("select exited with ".$nfds." fds\n");
+		&logthis("ins = ".unpack("b*",$ins).
+			 " readvec = ".unpack("b*",$$readvec)."\n");
+		&logthis("outs = ".unpack("b*",$outs).
+			 " writevec = ".unpack("b*",$$writevec)."\n");
+	    }
 	    $$readvec  = $ins;
 	    $$writevec = $outs;
 	    return;
 	} else {
+	    if($DEBUG) {
+		&logthis("Select exited with no bits set in mask\n");
+	    }
 	    die "Select failed" unless $! == EINTR;
 	}
     }
@@ -707,7 +679,6 @@
     }
 }
 # ---------------------------------------------------------- End make_new_child
-}
 
 # nonblock($socket) puts socket into nonblocking mode
 sub nonblock {

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