--- loncom/Attic/lonc 2002/03/26 04:37:59 1.35
+++ loncom/Attic/lonc 2002/05/11 21:17:39 1.40
@@ -5,7 +5,7 @@
# provides persistent TCP connections to the other servers in the network
# through multiplexed domain sockets
#
-# $Id: lonc,v 1.35 2002/03/26 04:37:59 foxr Exp $
+# $Id: lonc,v 1.40 2002/05/11 21:17:39 harris41 Exp $
#
# Copyright Michigan State University Board of Trustees
#
@@ -48,6 +48,10 @@
# 3/07/02 Ron Fox
# based on nonforker from Perl Cookbook
# - server who multiplexes without forking
+# 5/11/2002 Scott Harrison
+
+use lib '/home/httpd/lib/perl/';
+use LONCAPA::Configuration;
use POSIX;
use IO::Socket;
@@ -71,18 +75,11 @@ $DEBUG = 0; # Set to 1 for annoyingly
$SIG{QUIT}=\&catchexception;
$SIG{__DIE__}=\&catchexception;
-# ------------------------------------ Read httpd access.conf and get variables
-&status("Read access.conf");
-open (CONFIG,"/etc/httpd/conf/access.conf") || die "Can't read access.conf";
-
-while ($configline=<CONFIG>) {
- if ($configline =~ /PerlSetVar/) {
- my ($dummy,$varname,$varvalue)=split(/\s+/,$configline);
- chomp($varvalue);
- $perlvar{$varname}=$varvalue;
- }
-}
-close(CONFIG);
+# ------------------------------------------- Read access.conf and loncapa.conf
+&status("Read access.conf and loncapa.conf");
+my $perlvarref=LONCAPA::Configuration::read_conf('access.conf','loncapa.conf');
+my %perlvar=%{$perlvarref};
+undef $perlvarref;
# ----------------------------- Make sure this process is running from user=www
&status("Check user ID");
@@ -175,7 +172,14 @@ $SIG{USR1} = \&USRMAN;
# And maintain the population.
while (1) {
my $deadpid = wait; # Wait for the next child to die.
- # See who died and start new one
+ # See who died and start new one
+ # or a signal (e.g. USR1 for restart).
+ # if a signal, the wait will fail
+ # This is ordinarily detected by
+ # checking for the existence of the
+ # pid index inthe children hash since
+ # the return value from a failed wait is -1
+ # which is an impossible PID.
&status("Woke up");
my $skipping='';
@@ -315,120 +319,65 @@ unless (
%outbuffer = ();
%ready = ();
%servers = (); # To be compatible with make filevector. indexed by
- # File descriptors, values are file descriptors.
+ # File ids, values are sockets.
# note that the accept socket is omitted.
tie %ready, 'Tie::RefHash';
-nonblock($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 +395,12 @@ sub MakeFileVector
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 +411,7 @@ sub MakeFileVector
# 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 +430,19 @@ sub HandleOutput
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 +471,7 @@ sub HandleOutput
delete $inbufs->{$sock};
delete $readys->{$sock};
- close($$socket); # Close the client socket.
+ close($socket); # Close the client socket.
next;
}
} else { # Kludgy way to mark lond connection lost.
@@ -519,7 +480,7 @@ sub HandleOutput
status("Connection lost");
$remotesock->shutdown(2);
&logthis("Attempting to open a new connection");
- &openremot($conserver);
+ &openremote($conserver);
}
}
@@ -553,14 +514,21 @@ sub HandleInput
my $ibufs = shift;
my $obufs = shift;
my $ready = shift;
+ my $sock;
- foreach $sock (keys %sockets) {
+ if($DEBUG) {
+ &logthis("Entered HandleInput\n");
+ }
+ foreach $sock (keys %$sockets) {
my $socket = $sockets->{$sock};
- if(vec($selvec, $$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 = $$socket->recv($data, POSIX::BUFSIZ, 0);
+ my $rv = $socket->recv($data, POSIX::BUFSIZ, 0);
+ if($DEBUG) {
+ &logthis("Received $data from socket");
+ }
unless (defined($rv) && length $data) {
# Read an end of file.. this is a disconnect from the peer.
@@ -571,7 +539,7 @@ sub HandleInput
delete $ready->{$sock};
status("Idle");
- close $$socket;
+ close $socket;
next;
}
# Append the read data to the input buffer. If the buffer
@@ -592,6 +560,46 @@ sub HandleInput
}
}
+# DoSelect: does a select with no timeout. On signal (errno == EINTR),
+# the select is retried until there are items in the returned
+# vectors.
+#
+# Parameters:
+# \$readvec - Reference to a vector of file descriptors to
+# check for readability.
+# \$writevec - Reference to a vector of file descriptors to check for
+# writability.
+# On exit, the referents are modified with vectors indicating which
+# file handles are readable/writable.
+#
+sub DoSelect {
+ my $readvec = shift;
+ my $writevec= shift;
+ my $outs;
+ my $ins;
+
+ while (1) {
+ 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 $! == EINTR;
+ }
+ }
+}
+
# handle($socket) deals with all pending requests for $client
#
sub handle {
@@ -677,7 +685,6 @@ sub handle {
}
}
# ---------------------------------------------------------- End make_new_child
-}
# nonblock($socket) puts socket into nonblocking mode
sub nonblock {
@@ -867,8 +874,25 @@ sub checkchildren {
sub USRMAN {
&logthis("USR1: Trying to establish connections again");
- %childatt=();
- &checkchildren();
+ #
+ # It is really important not to just clear the childatt hash or we will
+ # lose all memory of the children. What we really want to do is this:
+ # For each index where childatt is >= $childmaxattempts
+ # Zero the associated counter and do a make_child for the host.
+ # Regardles, the childatt entry is zeroed:
+ my $host;
+ foreach $host (keys %childatt) {
+ if ($childatt{$host} >= $childmaxattempts) {
+ $childatt{$host} = 0;
+ &logthis("<font color=green>INFO: Restarting child for server: "
+ .$host."</font>\n");
+ make_new_child($host);
+ }
+ else {
+ $childatt{$host} = 0;
+ }
+ }
+ &checkchildren(); # See if any children are still dead...
}
# -------------------------------------------------- Non-critical communication