--- /dev/null
+#!/usr/bin/perl
+# helper multiplexer. Talks to squid using the multiplexed variant of
+# the helper protocol, and maintains a farm of synchronous helpers
+# helpers are lazily started, as many as needed.
+# see helper-mux.README for further informations
+#
+# AUTHOR: Francesco Chemolli <kinkie@squid-cache.org>
+#
+# SQUID Web Proxy Cache http://www.squid-cache.org/
+# ----------------------------------------------------------
+#
+# Squid is the result of efforts by numerous individuals from
+# the Internet community; see the CONTRIBUTORS file for full
+# details. Many organizations have provided support for Squid's
+# development; see the SPONSORS file for full details.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
+
+use Getopt::Std;
+use Data::Dumper;
+use FileHandle;
+use IPC::Open2;
+
+#mux-ed format: "slot_num non_muxed_request"
+
+# options handling
+my %opts=();
+$Getopt::Std::STANDARD_HELP_VERSION=1;
+getopts('h', \%opts) or die ("unrecognized options");
+if (defined $opts{h}) {
+ HELP_MESSAGE();
+ exit 0;
+}
+my $actual_helper_cmd=join(" ",@ARGV);
+
+# variables initialization
+my %helpers=();
+my $rvec='';
+vec($rvec,0,1)=1; #stdin
+my $nfound;
+my ($rd,$wr,$cl);
+
+# signal handlers
+$SIG{'HUP'}=\&dump_state;
+$SIG{'CHLD'}=\&reaper;
+# TODO: signal handling for child dying
+
+# main loop
+$|=1;
+while(1) {
+ print STDERR "selecting\n";
+ $nfound=select($rd=$rvec,undef,undef,undef);
+ #$nfound=select($rd=$rvec,undef,$cl=$rvec,undef);
+ print STDERR "nfound: $nfound\n";
+ if ($nfound == -1 ) {
+ print STDERR "error in select: $!\n";
+ if ($!{ERESTART} || $!{EAGAIN} || $!{EINTR}) {
+ next;
+ }
+ exit 1;
+ }
+ #print STDERR "cl: ", unpack("b*", $cl) ,"\n";
+ print STDERR "rd: ", unpack("b*", $rd) ,"\n";
+ # stdin is special
+ #if (vec($cl,0,1)==1) { #stdin was closed
+ # print STDERR "stdin closed\n";
+ # exit(0);
+ #}
+ if (vec($rd,0,1)==1) { #got stuff from stdin
+ #TODO: handle leftover buffers? I hope that 40kb are enough..
+ $nread=sysread(STDIN,$_,40960); # read 40kb
+ # clear the signal-bit, stdin is special
+ vec($rd,0,1)=0;
+ if ($nread==0) {
+ print STDERR "nothing read from stdin\n";
+ exit 0;
+ }
+ foreach $req (split("\n",$_)) {
+ dispatch_request($_);
+ }
+ }
+ # find out if any filedesc was closed
+ if ($cl != 0) {
+ #TODO: better handle helper restart
+ print STDERR "helper crash?";
+ exit 1;
+ }
+ #TODO: is it possible to test the whole bitfield in one go?
+ # != won't work.
+ foreach $h (keys %helpers) {
+ my %hlp=%{$helpers{$h}};
+ #print STDERR "examining helper slot $h, fileno $hlp{fno}, filemask ", vec($rd,$hlp{fno},1) , "\n";
+ if (vec($rd,$hlp{fno},1)==1) {
+ #print STDERR "found\n";
+ handle_helper_response($h);
+ }
+ #no need to clear, it will be reset when iterating
+ }
+}
+
+sub dispatch_request {
+ my $line=$_[0];
+ my %h;
+
+ #print STDERR "dispatching request $_";
+ $line =~ /^(\d+) (.*)$/;
+ my $slot=$1;
+ my $req=$2;
+
+ if (!exists($helpers{$slot})) {
+ $helpers{$slot}=init_subprocess();
+ }
+ $h=$helpers{$slot};
+ $wh=$h->{wh};
+ $rh=$h->{rh};
+ $h->{lastcmd}=$req;
+ print $wh "$req\n";
+}
+
+# gets in a slot number having got some response.
+# reads the response from the helper and sends it back to squid
+# prints the response back
+sub handle_helper_response {
+ my $h=$_[0];
+ my ($nread,$resp);
+ $nread=sysread($helpers{$h}->{rh},$resp,40960);
+ #print STDERR "got $resp from slot $h\n";
+ print $h, " ", $resp;
+ delete $helpers{$h}->{lastcmd};
+}
+
+# a subprocess is a hash with members:
+# pid => $pid
+# rh => read handle
+# wh => write handle
+# fno => file number of the read handle
+# lastcmd => the command "in flight"
+# a ref to such a hash is returned by this call
+sub init_subprocess {
+ my %rv=();
+ my ($rh,$wh,$pid);
+ $pid=open2($rh,$wh,$actual_helper_cmd);
+ if ($pid == 0) {
+ die "Failed to fork helper process";
+ }
+ select($rh); $|=1;
+ select($wh); $|=1;
+ select(STDOUT);
+ $rv{rh}=$rh;
+ $rv{wh}=$wh;
+ $rv{pid}=$pid;
+ $rv{fno}=fileno($rh);
+ print STDERR "fileno is $rv{fno}\n";
+ vec($rvec,$rv{fno},1)=1;
+ return \%rv;
+}
+
+sub HELP_MESSAGE {
+ print STDERR <<EOF
+$0 options:
+ -h this help message
+ arguments:
+ the actual helper executable and its arguments.
+ it's advisable to prefix it with "--" to avoid confusion
+EOF
+}
+
+sub dump_state {
+ $SIG{'HUP'}=\&dump_state;
+ print STDERR "Helpers state:\n",Dumper(\%helpers),"\n";
+}
+
+# finds and returns the slot number of a helper, -1 if not found
+# args: - key in helpers
+# - value to look for
+sub find_helper_slot {
+ my ($k,$v) = @_;
+ foreach (keys %helpers) {
+ return $_ if $helpers{$k}==$v;
+ }
+ return -1;
+}
+
+sub reaper {
+ my $child=wait;
+ print STDERR "child $child died\n";
+ $SIG{'CHLD'}=\&reaper;
+ $slot = find_helper_slot('pid',$child);
+ print STDERR "slot is $slot\n";
+ #TODO: find the died child, if it was mid-process through a request
+ # send a "BH" to squid and de-init its data-structs here
+ exit 1;
+}
+
projects / thirdparty / squid.git / commitdiff
