From 698fc01595227238d8fab484675ec4c6935b24a1 Mon Sep 17 00:00:00 2001 From: Matt Sergeant Date: Tue, 5 Jul 2005 15:16:36 +0000 Subject: [PATCH] Make pid-file optional Use known-safe fork code for forking No more SIGCHLD for managing zombies (Peter Holzer) Don't block on accept() so we can call REAPER every second git-svn-id: https://svn.perl.org/qpsmtpd/trunk@461 958fd67b-6ff1-0310-b445-bb7760255be9 --- qpsmtpd-forkserver | 94 ++++++++++++++++++++++++++++++---------------- 1 file changed, 62 insertions(+), 32 deletions(-) diff --git a/qpsmtpd-forkserver b/qpsmtpd-forkserver index c58c9c1..891d6e9 100755 --- a/qpsmtpd-forkserver +++ b/qpsmtpd-forkserver @@ -10,6 +10,7 @@ use lib 'lib'; use Qpsmtpd::TcpServer; use Qpsmtpd::Constants; use IO::Socket; +use IO::Select; use Socket; use Getopt::Long; use POSIX qw(:sys_wait_h :errno_h :signal_h); @@ -22,7 +23,7 @@ my $PORT = 2525; # port number my $LOCALADDR = '0.0.0.0'; # ip address to bind to my $USER = 'smtpd'; # user to suid to my $MAXCONNIP = 5; # max simultaneous connections from one IP -my $PID_FILE = '/var/run/qpsmtpd.pid'; +my $PID_FILE = ''; sub usage { print <<"EOT"; @@ -43,7 +44,7 @@ GetOptions('h|help' => \&usage, 'm|max-from-ip=i' => \$MAXCONNIP, 'p|port=i' => \$PORT, 'u|user=s' => \$USER, - 'pid-file=s' => \$PID_FILE, + 'pid-file=s' => \$PID_FILE, ) || &usage; # detaint the commandline @@ -51,7 +52,6 @@ if ($PORT =~ /^(\d+)$/) { $PORT = $1 } else { &usage } if ($LOCALADDR =~ /^([\d\w\-.]+)$/) { $LOCALADDR = $1 } else { &usage } if ($USER =~ /^([\w\-]+)$/) { $USER = $1 } else { &usage } if ($MAXCONN =~ /^(\d+)$/) { $MAXCONN = $1 } else { &usage } -if ($PID_FILE =~ m#^(/[\w\d/\-.]+)$#) { $PID_FILE = $1 } else { &usage } delete $ENV{ENV}; $ENV{PATH} = '/bin:/usr/bin:/var/qmail/bin'; @@ -59,7 +59,6 @@ $ENV{PATH} = '/bin:/usr/bin:/var/qmail/bin'; my %childstatus = (); sub REAPER { - $SIG{CHLD} = \&REAPER; while ( defined(my $chld = waitpid(-1, WNOHANG)) ){ last unless $chld > 0; ::log(LOGINFO,"cleaning up after $chld"); @@ -73,7 +72,6 @@ sub HUNTSMAN { exit(0); } -$SIG{CHLD} = \&REAPER; $SIG{INT} = \&HUNTSMAN; $SIG{TERM} = \&HUNTSMAN; @@ -82,27 +80,38 @@ my $server = IO::Socket::INET->new(LocalPort => $PORT, LocalAddr => $LOCALADDR, Proto => 'tcp', Reuse => 1, + Blocking => 0, Listen => SOMAXCONN ) or die "Creating TCP socket $LOCALADDR:$PORT: $!\n"; +IO::Handle::blocking($server, 0); +my $sel = IO::Select->new(); +$sel->add($server); -if (-e $PID_FILE) { - open PID, "+<$PID_FILE" - or die "open pid_file: $!\n"; - my $running_pid = ; chomp $running_pid; - if ($running_pid =~ /(\d+)/) { - $running_pid = $1; - if (kill 0, $running_pid) { - die "Found an already running qpsmtpd with pid $running_pid.\n"; +if ($PID_FILE) { + if ($PID_FILE =~ m#^(/[\w\d/\-.]+)$#) { $PID_FILE = $1 } else { &usage } + if (-e $PID_FILE) { + open PID, "+<$PID_FILE" + or die "open pid_file: $!\n"; + my $running_pid = ; chomp $running_pid; + if ($running_pid =~ /(\d+)/) { + $running_pid = $1; + if (kill 0, $running_pid) { + die "Found an already running qpsmtpd with pid $running_pid.\n"; + } } + seek PID, 0, 0 + or die "Could not seek back to beginning of $PID_FILE: $!\n"; + } else { + open PID, ">$PID_FILE" + or die "open pid_file: $!\n"; } - seek PID, 0, 0 - or die "Could not seek back to beginning of $PID_FILE: $!\n"; -} else { - open PID, ">$PID_FILE" - or die "open pid_file: $!\n"; + print PID $$,"\n"; + close PID; } -print PID $$,"\n"; -close PID; + +# Load plugins here +my $qpsmtpd = Qpsmtpd::TcpServer->new(); +$qpsmtpd->load_plugins; # Drop privileges my (undef, undef, $quid, $qgid) = getpwnam $USER or @@ -122,10 +131,6 @@ POSIX::setuid($quid) or die "unable to change uid: $!\n"; $> = $quid; -# Load plugins here -my $qpsmtpd = Qpsmtpd::TcpServer->new(); -$qpsmtpd->load_plugins; - ::log(LOGINFO,"Listening on port $PORT"); ::log(LOGINFO, 'Running as user '. (getpwuid($>) || $>) . @@ -133,26 +138,28 @@ $qpsmtpd->load_plugins; (getgrgid($)) || $))); while (1) { + REAPER(); my $running = scalar keys %childstatus; while ($running >= $MAXCONN) { ::log(LOGINFO,"Too many connections: $running >= $MAXCONN. Waiting one second."); sleep(1) ; + REAPER(); $running = scalar keys %childstatus; + } + if (!$sel->can_read(1)) { + next; } my $hisaddr = accept(my $client, $server); if (!$hisaddr) { # possible something condition... next; } + IO::Handle::blocking($client, 1); my ($port, $iaddr) = sockaddr_in($hisaddr); if ($MAXCONNIP) { my $num_conn = 1; # seed with current value - # If we for-loop directly over values %childstatus, a SIGCHLD - # can call REAPER and slip $rip out from under us. Causes - # "Use of freed value in iteration" under perl 5.8.4. - my @rip = values %childstatus; - foreach my $rip (@rip) { + foreach my $rip (values %childstatus) { ++$num_conn if (defined $rip && $rip eq $iaddr); } @@ -166,7 +173,7 @@ while (1) { next; } } - my $pid = fork; + my $pid = safe_fork(); if ($pid) { # parent $childstatus{$pid} = $iaddr; # add to table @@ -175,7 +182,6 @@ while (1) { close($client); next; } - die "fork: $!" unless defined $pid; # failure # otherwise child # all children should have different seeds, to prevent conflicts @@ -213,7 +219,7 @@ while (1) { remote_port => $port, ); $qpsmtpd->run(); - + exit; # child leaves } @@ -222,6 +228,30 @@ sub log { $qpsmtpd->log($level,$message); } +### routine to protect process during fork +sub safe_fork { + + ### block signal for fork + my $sigset = POSIX::SigSet->new(SIGINT); + POSIX::sigprocmask(SIG_BLOCK, $sigset) + or die "Can't block SIGINT for fork: [$!]\n"; + + ### fork off a child + my $pid = fork; + unless( defined $pid ){ + die "Couldn't fork: [$!]\n"; + } + + ### make SIGINT kill us as it did before + $SIG{INT} = 'DEFAULT'; + + ### put back to normal + POSIX::sigprocmask(SIG_UNBLOCK, $sigset) + or die "Can't unblock SIGINT for fork: [$!]\n"; + + return $pid; +} + __END__ 1;