[LON-CAPA-cvs] cvs: loncom / lonc
foxr
lon-capa-cvs@mail.lon-capa.org
Tue, 26 Mar 2002 04:37:59 -0000
foxr Mon Mar 25 23:37:59 2002 EDT
Modified files:
/loncom lonc
Log:
Inserted support functions to allow restructuring the lonc main loop.
Note that no actual logic changes have been implemented with this
edit.
Index: loncom/lonc
diff -u loncom/lonc:1.34 loncom/lonc:1.35
--- loncom/lonc:1.34 Tue Mar 19 22:44:11 2002
+++ loncom/lonc Mon Mar 25 23:37:59 2002
@@ -5,7 +5,7 @@
# provides persistent TCP connections to the other servers in the network
# through multiplexed domain sockets
#
-# $Id: lonc,v 1.34 2002/03/20 03:44:11 foxr Exp $
+# $Id: lonc,v 1.35 2002/03/26 04:37:59 foxr Exp $
#
# Copyright Michigan State University Board of Trustees
#
@@ -314,6 +314,9 @@
%inbuffer = ();
%outbuffer = ();
%ready = ();
+%servers = (); # To be compatible with make filevector. indexed by
+ # File descriptors, values are file descriptors.
+ # note that the accept socket is omitted.
tie %ready, 'Tie::RefHash';
@@ -326,8 +329,17 @@
my $rv;
my $data;
- # check for new information on the connections we have
+ 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)) {
@@ -421,7 +433,167 @@
# ------------------------------------------------------- End of make_new_child
+
+#
+# Make a vector of file descriptors to wait for in a select.
+# parameters:
+# \%fdhash -reference to a hash which has IO::Socket's as indices.
+# We only care about the indices, not the values.
+# A select vector is created from all indices of the hash.
+
+sub MakeFileVector
+{
+ my $fdhash = shift;
+ my $selvar = "";
+
+ foreach $socket (keys %fdhash) {
+ vec($selvar, ($fdhash->{$socket})->fileno, 1) = 1;
+ }
+ return $selvar;
+}
+
+
+#
+# HandleOutput:
+# 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.
+# \%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
+# of those sockets will be present in $selvector.
+# For each one of those, we will attempt to write the output
+# buffer to the socket. Note that we will assume that
+# the sockets are being run in non blocking mode.
+# \%inbufs - Reference to hash containing input buffers.
+# \%readys - Reference to hash containing flags for items with complete
+# requests.
+#
+sub HandleOutput
+{
+ my $selvector = shift;
+ my $sockets = shift;
+ my $buffers = shift;
+ my $inbufs = shift;
+ my $readys = shift;
+
+ foreach $sock (keys %buffers) {
+ my $socket = $sockets->{$sock};
+ if(vec($selvector, $$socket->fileno, 1)) { # $socket is writable.
+ my $rv = $$socket->send($buffers->{$sock}, 0);
+ $errno = $!;
+ unless ($buffers->{$sock} eq "con_lost\n") {
+ unless (defined $rv) { # Write failed... could be EINTR
+ unless ($errno == POSIX::EINTR) {
+ &logthis("Write failed on writable socket");
+ } # EINTR is not an error .. just retry.
+ next;
+ }
+ if( ($rv == length $buffers->{$sock}) ||
+ ($errno == POSIX::EWOULDBLOCK) ||
+ ($errno == POSIX::EAGAIN) || # same as above.
+ ($errno == POSIX::EINTR) || # signal during IO
+ ($errno == 0)) {
+ substr($buffers->{$sock}, 0, $rv)=""; # delete written part
+ delete $buffers->{$sock} unless length $buffers->{$sock};
+ } else {
+ # For some reason the write failed with an error code
+ # we didn't look for. Shutdown the socket.
+ &logthis("Unable to write data with ".$errno.": ".
+ "Dropping data: ".length($buffers->{$sock}).
+ ", $rv");
+ #
+ # kill off the buffers in the hash:
+
+ delete $buffers->{$sock};
+ delete $inbufs->{$sock};
+ delete $readys->{$sock};
+
+ close($$socket); # Close the client socket.
+ next;
+ }
+ } else { # Kludgy way to mark lond connection lost.
+ &logthis(
+ "<font color=red>CRITICAL lond connection lost</font>");
+ status("Connection lost");
+ $remotesock->shutdown(2);
+ &logthis("Attempting to open a new connection");
+ &openremot($conserver);
+ }
+
+ }
+ }
+
+}
+#
+# HandleInput - Deals with input on client sockets.
+# Each socket has an associated input buffer.
+# For each readable socket, the currently available
+# data is appended to this buffer.
+# If necessary, the buffer is created.
+# On various failures, we may shutdown the client.
+# Parameters:
+# $selvec - Vector of readable sockets.
+# \%sockets - Refers to the Hash of sockets indexed by sockets.
+# Each of these may or may not have it's fd bit set
+# in the $selvec.
+# \%ibufs - Refers to the hash of input buffers indexed by socket.
+# \%obufs - Hash of output buffers indexed by socket.
+# \%ready - Hash of ready flags indicating the existence of a completed
+# Request.
+sub HandleInput
+{
+
+ # Marshall the parameters. Note that the hashes are actually
+ # references not values.
+
+ my $selvec = shift;
+ my $sockets = shift;
+ my $ibufs = shift;
+ my $obufs = shift;
+ my $ready = shift;
+
+ foreach $sock (keys %sockets) {
+ my $socket = $sockets->{$sock};
+ if(vec($selvec, $$socket->fileno, 1)) { # Socket which is readable.
+
+ # Attempt to read the data and do error management.
+ my $data = '';
+ my $rv = $$socket->recv($data, POSIX::BUFSIZ, 0);
+ unless (defined($rv) && length $data) {
+
+ # Read an end of file.. this is a disconnect from the peer.
+
+ delete $sockets->{$sock};
+ delete $ibufs->{$sock};
+ delete $obufs->{$sock};
+ delete $ready->{$sock};
+
+ status("Idle");
+ close $$socket;
+ next;
+ }
+ # Append the read data to the input buffer. If the buffer
+ # now contains a \n the request is complete and we can
+ # mark this in the $ready hash (one request for each \n.)
+
+ $ibufs->{$sock} .= $data;
+ while($ibufs->{$sock} =~ s/(.*\n)//) {
+ push(@{$ready->{$sock}}, $1);
+ }
+
+ }
+ }
+ # Now handle any requests which are ready:
+
+ foreach $client (keys %ready) {
+ handle($client);
+ }
+}
+
# handle($socket) deals with all pending requests for $client
+#
sub handle {
# requests are in $ready{$client}
# send output to $outbuffer{$client}