fp@220: #!/usr/bin/perl -w
fp@220: 
fp@220: #------------------------------------------------------------------------------
fp@220: #
fp@220: #  Copyright (C) 2006  Ingenieurgemeinschaft IgH
fp@220: #
fp@220: #  This file is part of the IgH EtherCAT Master.
fp@220: #
fp@220: #  The IgH EtherCAT Master is free software; you can redistribute it
fp@220: #  and/or modify it under the terms of the GNU General Public License
fp@220: #  as published by the Free Software Foundation; version 2 of the License.
fp@220: #
fp@220: #  The IgH EtherCAT Master is distributed in the hope that it will be
fp@220: #  useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
fp@220: #  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
fp@220: #  GNU General Public License for more details.
fp@220: #
fp@220: #  You should have received a copy of the GNU General Public License
fp@220: #  along with the IgH EtherCAT Master; if not, write to the Free Software
fp@220: #  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
fp@220: #
fp@220: #------------------------------------------------------------------------------
fp@220: #
fp@220: #  Multithreaded Server
fp@220: #  according to the example from "Programming Perl"
fp@220: #  this code is improved according to the example from
fp@220: #  perldoc perlipc, so now safely being usable under Perl 5.8
fp@220: #  (see note (*))
fp@220: #
fp@220: #  works with read/write on a device-file
fp@220: #
fp@220: #------------------------------------------------------------------------------
fp@220: 
fp@220: require 5.002;
fp@220: use strict;
fp@220: BEGIN { $ENV{PATH} = '/opt/msr/bin:/usr/bin:/bin' }
fp@220: use Socket;
fp@220: use Carp;
fp@220: use FileHandle;
fp@220: use Getopt::Std;
fp@220: 
fp@220: use Sys::Syslog qw(:DEFAULT setlogsock);
fp@220: 
fp@220: use vars qw (
fp@220: 	     $self $pid $dolog $port $dev %opts $selfbase
fp@220: 	     $len $offset $stream $written $read $log $blksize
fp@220: 	     $instdir
fp@220: 	     $authfile %authhosts
fp@220: 	     );
fp@220: 
fp@220: 
fp@220: # Do logging to local syslogd by unix-domain socket instead of inetd
fp@220: setlogsock("unix");
fp@220: 
fp@220: # Prototypes and some little Tools
fp@220: sub spawn;
fp@220: sub logmsg {
fp@220:   my ($level, $debug, @text) = @_;
fp@220:   syslog("daemon|$level", @text) if $debug > $dolog;
fp@220: #  print STDERR "daemon|$level", @text, "\n" if $dolog;
fp@220: }
fp@220: sub out {
fp@220:   my $waitpid = wait;
fp@220:   logmsg("notice", 2, "$waitpid exited");
fp@220:   unlink "$selfbase.pid";
fp@220:   exit 0;
fp@220: }
fp@220: 
fp@220: sub help {
fp@220:   print "\n  usage: $0 [-l og] [-h elp] [-p port] [-d device]\n";
fp@220:   exit;
fp@220: }
fp@220: 
fp@220: # Process Options
fp@220: %opts = (
fp@220: 	 "l" => 1,
fp@220: 	 "h" => 0,
fp@220: 	 "p" => 2345,
fp@220: 	 "d" => "/dev/msr"
fp@220: 	 );
fp@220: 
fp@220: getopts("lhp:d:", \%opts);
fp@220: 
fp@220: help if $opts{"h"};
fp@220: 
fp@220: ( $self =  $0 ) =~ s+.*/++ ;
fp@220: ( $selfbase = $self ) =~ s/\..*//;
fp@220: $log = "$selfbase.log";
fp@220: $dolog = $opts{"l"};
fp@220: $port = $opts{"p"};
fp@220: $dev = $opts{"d"};
fp@220: $blksize = 1024; # try to write as much bytes
fp@220: $instdir = "/opt/msr";
fp@220: $authfile = "$instdir/etc/hosts.auth";
fp@220: 
fp@220: # Start logging
fp@220: openlog($self, 'pid');
fp@220: 
fp@220: # Flush Output, dont buffer
fp@220: $| = 1;
fp@220: 
fp@220: # first fork and run in background
fp@220: if ($pid = fork) {
fp@220: #  open LOG, ">$log" if $dolog;
fp@220: #  close LOG;
fp@220:   logmsg("notice", 2, "forked process: $pid\n");
fp@220:   exit 0;
fp@220: }
fp@220: 
fp@220: # Server tells about startup success
fp@220: open (PID, ">/$instdir/var/run/$selfbase.pid");
fp@220: print PID "$$\n";
fp@220: close PID;
fp@220: 
fp@220: # Cleanup on exit (due to kill -TERM signal)
fp@220: $SIG{TERM} = \&out;
fp@220: 
fp@220: # We use streams
fp@220: my $proto = getprotobyname('tcp');
fp@220: 
fp@220: # Open Server socket
fp@220: socket(Server, PF_INET, SOCK_STREAM, $proto) or die "socket: $!";
fp@220: setsockopt(Server, SOL_SOCKET, SO_REUSEADDR, pack("l", 1))
fp@220:   or die "setsocketopt: $!";
fp@220: bind (Server, sockaddr_in($port, INADDR_ANY))
fp@220:   or die "bind: $!";
fp@220: listen (Server, SOMAXCONN)
fp@220:   or die "listen: $!";
fp@220: 
fp@220: %authhosts = ();
fp@220: # get authorized hosts
fp@220: open (AUTH, $authfile)
fp@220:   or logmsg ("notice", 2, "Could not read allowed hosts file: $authfile");
fp@220: while (<AUTH>) {
fp@220:     chomp;
fp@220:     my $host = lc $_;
fp@220:      if ($host =~ /^[\d\w]/) {
fp@220: 	 $authhosts{$_} = 1;
fp@220: 	 logmsg ("notice", 2, "Authorized host: >$host<");
fp@220:      }
fp@220: }
fp@220: close (AUTH);
fp@220: 
fp@220: # tell about open server socket
fp@220: logmsg ("notice", 2, "Server started at port $port");
fp@220: 
fp@220: my $waitedpid = 0;
fp@220: my $paddr;
fp@220: 
fp@220: # wait for children to return, thus avoiding zombies
fp@220: # improvement (*)
fp@220: use POSIX ":sys_wait_h";
fp@220: sub REAPER {
fp@220:   my $child;
fp@220:   while (($waitedpid = waitpid(-1,WNOHANG)) > 0) {
fp@220:     logmsg ("notice", 2, "reaped $waitedpid", ($? ? " with exit $?" : ""));
fp@220:   }
fp@220:   $SIG{CHLD} = \&REAPER;  # loathe sysV
fp@220: }
fp@220: 
fp@220: # also all sub-processes should wait for their children
fp@220: $SIG{CHLD} = \&REAPER;
fp@220: 
fp@220: # start a new server for every incoming request
fp@220: # improvement (*) -- loop forever
fp@220: 
fp@220: while ( 1 ) {
fp@220:   for ( $waitedpid = 0;
fp@220: 	($paddr = accept(Client,Server)) || $waitedpid;
fp@220: 	$waitedpid = 0, close Client ) {
fp@220:     next if $waitedpid and not $paddr;
fp@220:     my ($port, $iaddr) = sockaddr_in($paddr);
fp@220:     my $name = lc gethostbyaddr($iaddr, AF_INET);
fp@220:     my $ipaddr = inet_ntoa($iaddr);
fp@220:     my $n = 0;
fp@220: 
fp@220: # tell about the requesting client
fp@220:     logmsg ("info", 2, "Connection from >$ipaddr< ($name) at port $port");
fp@220: 
fp@220:     spawn sub {
fp@220:       my ($head, $hlen, $pos, $pegel, $typ, $siz, $nch, $nrec, $dat, $i, $j, $n, $llen); 
fp@220:       my ($watchpegel, $shmpegel);
fp@220:       my ($rin, $rout, $in, $line, $data_requested, $oversample);
fp@220:       my (@channels);
fp@220: 
fp@220: #   to use stdio on writing to Client
fp@220:       Client->autoflush();
fp@220: 
fp@220: #   Open Device
fp@220:       sysopen (DEV, "$dev", O_RDWR | O_NONBLOCK, 0666) or die("can't open $dev");
fp@220: 
fp@220: #   Bitmask to check for input on stdin
fp@220:       $rin = "";
fp@220:       vec($rin, fileno(Client), 1) = 1;
fp@220: 
fp@220: #   check for authorized hosts
fp@220:       my $access = 'deny';
fp@220:       $access = 'allow' if $authhosts{$ipaddr};
fp@220:       $line = "<remote_host host=\"$ipaddr\" access=\"$access\">\n";
fp@220:       logmsg ("info", 2, $line);
fp@220:       $len = length $line;
fp@220:       $offset = 0;
fp@220:       while ($len) {
fp@220: 	$written = syswrite (DEV, $line, $len, $offset);
fp@220: 	$len -= $written;
fp@220: 	$offset += $written;
fp@220:       }
fp@220: 
fp@220:       while ( 1 ) {
fp@220: 	$in = select ($rout=$rin, undef, undef, 0.0); # poll client
fp@220: #     look for any Input from Client
fp@220: 	if ($in) {
fp@220: #       exit on EOF
fp@220: 	  $len = sysread (Client, $line, $blksize) or exit;
fp@220: 	  logmsg("info", 0, "got $len bytes: \"$line\"");
fp@220: 	  $offset = 0;
fp@220: #       copy request to device
fp@220: 	  while ($len) {
fp@220: 	    $written = syswrite (DEV, $line, $len, $offset);
fp@220: 	    $len -= $written;
fp@220: 	    $offset += $written;
fp@220: 	  }
fp@220: 	}
fp@220: #     look for some output from device
fp@220: 	if ($len = sysread DEV, $stream, $blksize) {
fp@220: 	  print Client $stream;
fp@220: 	} else {
fp@220: 	  select undef, undef, undef, 0.1; # calm down if nothing on device
fp@220: 	}
fp@220:       }
fp@220:     };
fp@220:     logmsg("info", 2, "spawned\n");
fp@220:   }
fp@220:   logmsg("info", 2, "server loop\n");
fp@220: }
fp@220: 
fp@220: sub spawn {
fp@220:   my $coderef = shift;
fp@220: 
fp@220:   unless (@_ == 0 && $coderef && ref($coderef) eq 'CODE') {
fp@220:     confess "usage: spawn CODEREF";
fp@220:   }
fp@220:   my $pid;
fp@220:   if (!defined($pid = fork)) {
fp@220:     logmsg ("notice", 2, "fork failed: $!");
fp@220:     return;
fp@220:   } elsif ($pid) {
fp@220:     logmsg ("notice", 2, "Request $pid");
fp@220:     return; # Parent
fp@220:   }
fp@220: 
fp@220: # do not use fdup as in the original example
fp@220: # open (STDIN, "<&Client") or die "Can't dup client to stdin";
fp@220: # open (STDOUT, ">&Client") or die "Can't dup client to stdout";
fp@220: # STDOUT->autoflush();
fp@220:   exit &$coderef();
fp@220: }