/usr/share/perl5/Mail/SpamAssassin/SpamdForkScaling.pm is in spamassassin 3.4.1-8build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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#
# <@LICENSE>
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to you under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License. You may obtain a copy of the License at:
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# </@LICENSE>
package Mail::SpamAssassin::SpamdForkScaling;
use strict;
use warnings;
use bytes;
use re 'taint';
use Errno qw();
use Mail::SpamAssassin::Util qw(am_running_on_windows);
use Mail::SpamAssassin::Logger;
use Mail::SpamAssassin::Timeout;
use vars qw {
@PFSTATE_VARS %EXPORT_TAGS @EXPORT_OK
};
use base qw( Exporter );
@PFSTATE_VARS = qw(
PFSTATE_ERROR PFSTATE_STARTING PFSTATE_IDLE PFSTATE_BUSY PFSTATE_KILLED
PFORDER_ACCEPT PFSTATE_GOT_SIGCHLD
);
%EXPORT_TAGS = (
'pfstates' => [ @PFSTATE_VARS ]
);
@EXPORT_OK = ( @PFSTATE_VARS );
use constant PFSTATE_ERROR => -1;
use constant PFSTATE_STARTING => 0;
use constant PFSTATE_IDLE => 1;
use constant PFSTATE_BUSY => 2;
use constant PFSTATE_KILLED => 3;
use constant PFSTATE_GOT_SIGCHLD => 4;
use constant PFORDER_ACCEPT => 10;
###########################################################################
# change to 1 to enable the below test instrumentation points
use constant SUPPORT_TEST_INSTRUMENTATION => 0;
# test instrumentation point: simulate random child failures in 1 in
# every N lookups
our $TEST_MODE_CAUSE_RANDOM_KID_FAILURES = 0;
# test instrumentation point: simulate child->parent and parent->child
# write failures (needing retries) once in every N syswrite()s
our $TEST_MODE_CAUSE_RANDOM_WRITE_RETRIES = 0;
# test instrumentation point: simulate ping failures (for unspecified
# reasons) once in every N pings
our $TEST_MODE_CAUSE_RANDOM_PING_FAILURES = 0;
###########################################################################
# we use the following protocol between the master and child processes to
# control when they accept/who accepts: server tells a child to accept with a
# PF_ACCEPT_ORDER, child responds with "B$pid\n" when it's busy, and "I$pid\n"
# once it's idle again. In addition, the parent sends PF_PING_ORDER
# periodically to ping the child processes. Very simple protocol. Note that
# the $pid values are packed into 4 bytes so that the buffers are always of a
# known length; if you need to transfer longer data, assign a new protocol verb
# (the first char) and use the length of the following data buffer as the
# packed value.
use constant PF_ACCEPT_ORDER => "A....\n";
use constant PF_PING_ORDER => "P....\n";
# timeout for a sysread() on the command channel. if we go this long
# without a message from the spamd parent or child, it's an error.
use constant TOUT_READ_MAX => 300;
# interval between "ping" messages from the spamd parent to all children,
# used as a sanity check to ensure TOUT_READ_MAX isn't hit when things
# are functional.
use constant TOUT_PING_INTERVAL => 150;
###########################################################################
sub new {
my $class = shift;
$class = ref($class) || $class;
my $self = shift;
if (!defined $self) { $self = { }; }
bless ($self, $class);
$self->{kids} = { };
$self->{overloaded} = 0;
$self->{min_children} ||= 1;
$self->{server_last_ping} = time;
$self;
}
###########################################################################
# Parent methods
sub add_child {
my ($self, $pid) = @_;
$self->set_child_state ($pid, PFSTATE_STARTING);
}
# this is called by the SIGCHLD handler in spamd. The idea is that
# main_ping_kids etc. can mark a child as probably dead ("K" state), but until
# SIGCHLD is received, the process is still around (in some form), so it
# shouldn't be removed from the list until it's confirmed dead.
#
sub child_exited {
my ($self, $pid) = @_;
dbg("prefork: child $pid: just exited");
# defer removal from the list until after return from the signal
# handler; it seems that we may be corrupting the list structure
# by deleting the {kids} hash entry from a sig handler. (bug 5422)
$self->set_child_state ($pid, PFSTATE_GOT_SIGCHLD);
# note this for the select()-caller's benefit
$self->{child_just_exited} = 1;
}
sub post_sigchld_cleanup {
my ($self) = @_;
my @pids = grep { $self->{kids}->{$_} == PFSTATE_GOT_SIGCHLD }
keys %{$self->{kids}};
return unless @pids;
foreach my $pid (@pids) {
delete $self->{kids}->{$pid}; # remove from list
# remove the child from the backchannel list, too
$self->{backchannel}->delete_socket_for_child($pid);
}
# ensure we recompute, so that we don't try to tell that child to
# accept a request, only to find that it's died in the meantime.
$self->compute_lowest_child_pid();
}
# this is called by SIGTERM and SIGHUP handlers, to ensure that new
# kids aren't added while the main code is killing the old ones
# and planning to exit.
#
sub set_exiting_flag {
my ($self) = @_;
$self->{am_exiting} = 1;
}
sub child_error_kill {
my ($self, $pid, $sock) = @_;
warn "prefork: killing failed child $pid fd=".
((defined $sock && defined $sock->fileno) ? $sock->fileno : "undefined");
# close the socket and remove the child from our list
$self->set_child_state ($pid, PFSTATE_KILLED);
#Bug 6304 research
#info("6304: prefork: child_error_kill called - %s", $pid);
kill 'INT' => $pid
or warn "prefork: kill of failed child $pid failed: $!\n";
$self->{backchannel}->delete_socket_for_child($pid);
if (defined $sock && defined $sock->fileno()) {
$self->{backchannel}->remove_from_selector($sock);
}
if ($sock) {
$sock->close or info("prefork: error closing socket: $!");
}
delete $self->{kids}->{$pid}; # remove from list
# ensure we recompute, so that we don't try to tell that child to
# accept a request, only to find that it's died in the meantime.
$self->compute_lowest_child_pid();
warn "prefork: killed child $pid\n";
}
sub set_child_state {
my ($self, $pid, $state) = @_;
# I keep misreading this -- so: this says, if the child is starting, or is
# dying, or it has an entry in the {kids} hash, then allow the state to be
# set. otherwise the update can be ignored.
if ($state == PFSTATE_STARTING || $state == PFSTATE_KILLED ||
$state == PFSTATE_GOT_SIGCHLD || exists $self->{kids}->{$pid})
{
$self->{kids}->{$pid} = $state;
dbg("prefork: child $pid: entering state $state");
$self->compute_lowest_child_pid();
} else {
dbg("prefork: child $pid: ignored new state $state, already exited?");
}
}
sub compute_lowest_child_pid {
my ($self) = @_;
my @pids = grep { $self->{kids}->{$_} == PFSTATE_IDLE }
keys %{$self->{kids}};
my $l = shift @pids;
foreach my $p (@pids) {
if ($l > $p) { $l = $p };
}
$self->{lowest_idle_pid} = $l;
dbg("prefork: new lowest idle kid: ".
($self->{lowest_idle_pid} ? $self->{lowest_idle_pid} : 'none'));
}
###########################################################################
sub set_server_fh {
my ($self, @fhs) = @_;
$self->{server_fh} = [];
$self->{server_fileno} = [];
foreach my $fh (@fhs) {
next unless defined $fh;
push @{$self->{server_fh}}, $fh;
push @{$self->{server_fileno}}, $fh->fileno();
}
}
sub main_server_poll {
my ($self, $tout) = @_;
my $rin = ${$self->{backchannel}->{selector}};
if ($self->{overloaded}) {
# don't select on the server fh -- we already KNOW that's ready,
# since we're overloaded
$self->vec_all(\$rin, $self->{server_fileno}, 0);
}
# clean up any fresh zombies before we select()
$self->post_sigchld_cleanup();
my ($rout, $eout, $nfound, $timeleft, $selerr);
# use alarm to back up select()'s built-in alarm, to debug Theo's bug.
# not that I can remember what Theo's bug was, but hey ;) A good
# 60 seconds extra on the alarm() should make that quite rare...
my $timer = Mail::SpamAssassin::Timeout->new({ secs => ($tout*2) + 60 });
$timer->run(sub {
# right before select() syscall, but after alarm(), eval scope, etc.
$self->{child_just_exited} = 0;
($nfound, $timeleft) = select($rout=$rin, undef, $eout=$rin, $tout);
$selerr = $! if !defined $nfound || $nfound < 0;
});
# in case any kids exited during select()
$self->post_sigchld_cleanup();
# bug 4696: under load, the process can go for such a long time without
# being context-switched in, that when it does return the alarm() fires
# before the select() timeout does. Treat this as a select() timeout
if ($timer->timed_out) {
dbg("prefork: select timed out (via alarm)");
$nfound = 0;
$timeleft = 0;
}
# errors; handle undef *or* -1 returned. do this before "errors on
# the handle" below, since an error condition is signalled both via
# a -1 return and a $eout bit.
if (!defined $nfound || $nfound < 0)
{
if (exists &Errno::EINTR && $selerr == &Errno::EINTR)
{
# this happens if the process is signalled during the select(),
# for example if someone sends SIGHUP to reload the configuration.
# just return inmmediately
dbg("prefork: select returned err $selerr, probably signalled");
return;
}
# if a child exits during that select() call, it generates a spurious
# error, like this:
#
# Jan 29 12:53:17 dogma spamd[18518]: prefork: child states: BI
# Jan 29 12:53:17 dogma spamd[18518]: spamd: handled cleanup of child pid 13101 due to SIGCHLD
# Jan 29 12:53:17 dogma spamd[18518]: prefork: select returned -1! recovering:
#
# avoid by setting a boolean in the child_exited() callback and checking
# it here. log $! just in case, though.
if ($self->{child_just_exited} && $nfound == -1) {
dbg("prefork: select returned -1 due to child exiting, ignored ($selerr)");
return;
}
warn "prefork: select returned ".
(defined $nfound ? $nfound : "undef").
"! recovering: $selerr\n";
sleep 1; # avoid overload
return;
}
# errors on the handle?
# return them immediately, they may be from a SIGHUP restart signal
if ($self->vec_all(\$eout, $self->{server_fileno})) {
warn "prefork: select returned error on server filehandle: $selerr $!\n";
return;
}
# any action?
if (!$nfound) {
# none. periodically ping the children though just to ensure
# they're still alive and can hear us
my $now = time;
if ($now - $self->{server_last_ping} > TOUT_PING_INTERVAL) {
$self->main_ping_kids($now);
}
return;
}
# were the kids ready, or did we get signal?
if ($self->vec_all(\$rout, $self->{server_fileno})) {
# dbg("prefork: server fh ready");
# the server socket: new connection from a client
if (!$self->order_idle_child_to_accept()) {
# dbg("prefork: no idle kids, noting overloaded");
# there are no idle kids! we're overloaded, mark that
$self->{overloaded} = 1;
}
return;
}
# otherwise it's a status report from a child.
foreach my $fh ($self->{backchannel}->select_vec_to_fh_list($rout))
{
# just read one line. if there's more lines, we'll get them
# when we re-enter the can_read() select call above...
if ($self->read_one_message_from_child_socket($fh) == PFSTATE_IDLE)
{
dbg("prefork: child reports idle");
if ($self->{overloaded}) {
# if we were overloaded, then now that this kid is idle,
# we can use it to handle the waiting connection. zero
# the overloaded flag, anyway; if there's >1 waiting
# conn, they'll show up next time we do the select.
dbg("prefork: overloaded, immediately telling kid to accept");
if (!$self->order_idle_child_to_accept()) {
# this can happen if something is buggy in the child, and
# it has to be killed, resulting in no idle kids left
warn "prefork: lost idle kids, so still overloaded";
$self->{overloaded} = 1;
}
else {
dbg("prefork: no longer overloaded");
$self->{overloaded} = 0;
}
}
}
}
# now that we've ordered some kids to accept any new connections,
# increase/decrease the pool as necessary
$self->adapt_num_children();
}
sub main_ping_kids {
my ($self, $now) = @_;
$self->{server_last_ping} = $now;
keys %{$self->{backchannel}->{kids}}; # reset each() iterator
my ($sock, $kid);
while (($kid, $sock) = each %{$self->{backchannel}->{kids}}) {
# if the file handle is still defined ping the child
# bug 4852: if not, we've run into a race condition with the child's
# SIGCHLD handler... try killing again just in case something else happened
if (SUPPORT_TEST_INSTRUMENTATION && $TEST_MODE_CAUSE_RANDOM_PING_FAILURES &&
rand $TEST_MODE_CAUSE_RANDOM_PING_FAILURES < 1)
{
warn "prefork: TEST_MODE_CAUSE_RANDOM_PING_FAILURES simulating ping failure";
}
elsif (defined $sock && defined $sock->fileno) {
$self->syswrite_with_retry($sock, PF_PING_ORDER, $kid, 3) and next;
warn "prefork: write of ping failed to $kid fd=".$sock->fileno.": ".$!;
}
else {
warn "prefork: cannot ping $kid, file handle not defined, child likely ".
"to still be processing SIGCHLD handler after killing itself\n";
}
# note: this is safe according to the note in perldoc -f each; 'it is
# always safe to delete the item most recently returned by each()'
$self->child_error_kill($kid, $sock);
}
}
sub read_one_message_from_child_socket {
my ($self, $sock) = @_;
# "I b1 b2 b3 b4 \n " or "B b1 b2 b3 b4 \n "
my $line;
my $nbytes = $self->sysread_with_timeout($sock, \$line, 6, TOUT_READ_MAX);
if (!defined $nbytes || $nbytes == 0) {
dbg("prefork: child closed connection");
# stop it being select'd
my $fno = $sock->fileno;
if (defined $fno) {
$self->{backchannel}->remove_from_selector($sock);
$sock->close or info("prefork: error closing socket: $!");
}
return PFSTATE_ERROR;
}
if ($nbytes < 6) {
warn("prefork: child gave short message: len=$nbytes bytes=".
join(" ", unpack "C*", $line));
}
chomp $line;
if ($line =~ s/^I//) {
my $pid = unpack("l1", $line); # signed, as 'N' causes win32 bugs (bug 6356)
$self->set_child_state ($pid, PFSTATE_IDLE);
return PFSTATE_IDLE;
}
elsif ($line =~ s/^B//) {
my $pid = unpack("l1", $line);
$self->set_child_state ($pid, PFSTATE_BUSY);
return PFSTATE_BUSY;
}
else {
die "prefork: unknown message from child: '$line'";
return PFSTATE_ERROR;
}
}
###########################################################################
sub order_idle_child_to_accept {
my ($self) = @_;
my $kid = $self->{lowest_idle_pid};
if (defined $kid)
{
my $sock = $self->{backchannel}->get_socket_for_child($kid);
if (SUPPORT_TEST_INSTRUMENTATION && $TEST_MODE_CAUSE_RANDOM_KID_FAILURES) {
if (rand $TEST_MODE_CAUSE_RANDOM_KID_FAILURES < 1) {
$sock = undef; warn "prefork: TEST_MODE_CAUSE_RANDOM_KID_FAILURES simulating no socket for kid $kid";
}
}
if (!$sock)
{
# this should not happen, but if it does, trap it here
# before we attempt to call a method on an undef object
warn "prefork: oops! no socket for child $kid, killing";
$self->child_error_kill($kid, $sock);
# retry with another child
return $self->order_idle_child_to_accept();
}
if (!$self->syswrite_with_retry($sock, PF_ACCEPT_ORDER, $kid))
{
# failure to write to the child; bad news. call it dead
warn "prefork: killing rogue child $kid, failed to write on fd ".$sock->fileno.": $!\n";
$self->child_error_kill($kid, $sock);
# retry with another child
return $self->order_idle_child_to_accept();
}
dbg("prefork: ordered $kid to accept");
# now wait for it to say it's done that
my $ret = $self->wait_for_child_to_accept($kid, $sock);
if ($ret) {
return $ret;
} else {
# retry with another child
return $self->order_idle_child_to_accept();
}
}
else {
dbg("prefork: no spare children to accept, waiting for one to complete");
return;
}
}
sub wait_for_child_to_accept {
my ($self, $kid, $sock) = @_;
while (1) {
my $state = $self->read_one_message_from_child_socket($sock);
if ($state == PFSTATE_BUSY) {
return 1; # 1 == success
}
if ($state == PFSTATE_ERROR) {
return;
}
else {
warn "prefork: ordered child $kid to accept, but they reported state '$state', killing rogue";
$self->child_error_kill($kid, $sock);
$self->adapt_num_children();
sleep 1;
return;
}
}
}
sub child_now_ready_to_accept {
my ($self, $kid) = @_;
if ($self->{waiting_for_idle_child}) {
my $sock = $self->{backchannel}->get_socket_for_child($kid);
$self->syswrite_with_retry($sock, PF_ACCEPT_ORDER, $kid)
or die "prefork: $kid claimed it was ready, but write failed on fd ".
$sock->fileno.": ".$!;
$self->{waiting_for_idle_child} = 0;
}
}
###########################################################################
# Child methods
sub set_my_pid {
my ($self, $pid) = @_;
$self->{pid} = $pid; # save calling $$ all the time
}
sub update_child_status_idle {
my ($self) = @_;
# "I b1 b2 b3 b4 \n "
$self->report_backchannel_socket("I".pack("l",$self->{pid})."\n");
}
sub update_child_status_busy {
my ($self) = @_;
# "B b1 b2 b3 b4 \n "
$self->report_backchannel_socket("B".pack("l",$self->{pid})."\n");
}
sub report_backchannel_socket {
my ($self, $str) = @_;
my $sock = $self->{backchannel}->get_parent_socket();
$self->syswrite_with_retry($sock, $str, 'parent')
or die "syswrite() to parent failed: $!";
}
sub wait_for_orders {
my ($self) = @_;
my $sock = $self->{backchannel}->get_parent_socket();
while (1) {
# "A . . . . \n "
my $line;
my $nbytes = $self->sysread_with_timeout($sock, \$line, 6, TOUT_READ_MAX);
if (!defined $nbytes || $nbytes == 0) {
if ($sock->eof()) {
dbg("prefork: parent closed, exiting");
exit;
}
die "prefork: empty order from parent";
}
if ($nbytes < 6) {
warn("prefork: parent gave short message: len=$nbytes bytes=".
join(" ", unpack "C*", $line));
}
chomp $line;
if (index ($line, "P") == 0) { # string starts with "P" = ping
dbg("prefork: periodic ping from spamd parent");
if (am_running_on_windows()) {
sleep 2; # need this on win32 so that a child can get a signal
}
next;
}
if (index ($line, "A") == 0) { # string starts with "A" = accept
return PFORDER_ACCEPT;
}
else {
die "prefork: unknown order from parent: '$line'";
}
}
}
###########################################################################
sub sysread_with_timeout {
my ($self, $sock, $lineref, $toread, $timeout) = @_;
$$lineref = ''; # clear the output buffer
my $readsofar = 0;
my $deadline; # we only set this if the first read fails
my $buf;
retry_read:
my $nbytes = $sock->sysread($buf, $toread);
if (!defined $nbytes) {
unless ((exists &Errno::EAGAIN && $! == &Errno::EAGAIN)
|| (exists &Errno::EWOULDBLOCK && $! == &Errno::EWOULDBLOCK))
{
# an error that wasn't non-blocking I/O-related. that's serious
return;
}
# ok, we didn't get it first time. we'll have to start using
# select() and timeouts (which is slower). Don't warn just yet,
# as it's quite acceptable in our design to have to "block" on
# sysread()s here.
my $now = time();
my $tout = $timeout;
if (!defined $deadline) {
# set this. it'll be close enough ;)
$deadline = $now + $timeout;
}
elsif ($now > $deadline) {
# timed out! report failure
dbg("prefork: sysread(%d) failed after %.1f secs",
$sock->fileno, $timeout);
return;
}
else {
$tout = $deadline - $now; # the remaining timeout
$tout = 1 if ($tout <= 0); # ensure it's > 0
}
dbg("prefork: sysread(%d) not ready, wait max %.1f secs",
$sock->fileno, $tout);
my $rin = '';
vec($rin, $sock->fileno, 1) = 1;
my $nfound = select($rin, undef, undef, $tout);
defined $nfound && $nfound >= 0
or info("prefork: sysread_with_timeout select error: %s", $!);
goto retry_read;
}
elsif ($nbytes == 0) { # EOF
return $readsofar; # may be a partial read, or 0 for EOF
}
elsif ($nbytes == $toread) { # a complete read, nice.
$readsofar += $nbytes;
$$lineref .= $buf;
return $readsofar;
}
else {
# we want to know about this. this is not supposed to happen!
warn "prefork: partial read of $nbytes, toread=".$toread.
"sofar=".$readsofar." fd=".$sock->fileno.", recovering";
$readsofar += $nbytes;
$$lineref .= $buf;
$toread -= $nbytes;
goto retry_read;
}
die "assert: should not get here";
}
sub syswrite_with_retry {
my ($self, $sock, $buf, $targetname, $numretries) = @_;
$numretries ||= 10; # default 10 retries
my $written = 0;
my $try = 0;
retry_write:
$try++;
if ($try > 1) {
warn "prefork: syswrite(".$sock->fileno.") to $targetname failed on try $try";
if ($try > $numretries) {
warn "prefork: giving up";
return;
}
else {
# give it 1 second to recover
my $rout = '';
vec($rout, $sock->fileno, 1) = 1;
my $nfound = select(undef, $rout, undef, 1);
defined $nfound && $nfound >= 0
or info("prefork: syswrite_with_retry select error: %s", $!);
}
}
my $nbytes;
if (SUPPORT_TEST_INSTRUMENTATION && $TEST_MODE_CAUSE_RANDOM_WRITE_RETRIES &&
rand $TEST_MODE_CAUSE_RANDOM_WRITE_RETRIES < 1)
{
warn "prefork: TEST_MODE_CAUSE_RANDOM_WRITE_RETRIES simulating write failure";
$nbytes = undef; $! = &Errno::EAGAIN;
}
else {
$nbytes = $sock->syswrite($buf);
}
if (!defined $nbytes) {
unless ((exists &Errno::EAGAIN && $! == &Errno::EAGAIN)
|| (exists &Errno::EWOULDBLOCK && $! == &Errno::EWOULDBLOCK))
{
# an error that wasn't non-blocking I/O-related. that's serious
return;
}
warn "prefork: retrying syswrite(): $!";
goto retry_write;
}
else {
$written += $nbytes;
$buf = substr($buf, $nbytes);
if ($buf eq '') {
return $written; # it's complete, we can return
}
else {
warn "prefork: partial write of $nbytes to ".
$targetname.", towrite=".length($buf).
" sofar=".$written." fd=".$sock->fileno.", recovering";
goto retry_write;
}
}
die "assert: should not get here";
}
###########################################################################
# Master server code again
# this is pretty much the algorithm from perform_idle_server_maintainance() in
# Apache's "prefork" MPM. However: we don't do exponential server spawning,
# since our servers are a lot more heavyweight than theirs is.
sub adapt_num_children {
my ($self) = @_;
# don't start up new kids while main is working at killing the old ones
return if $self->{am_exiting};
my $kids = $self->{kids};
my $statestr = '';
my $num_idle = 0;
my @pids = sort { $a <=> $b } keys %{$kids};
my $num_servers = scalar @pids;
foreach my $pid (@pids) {
my $k = $kids->{$pid};
# note: race condition here. if a child exits between the keys() call
# above, and this point, then $k will be undef here due to its deletion
# from the hash in the SIGCHLD handler. This is harmless, but ugly, since
# it produces a 'Use of uninitialized value in numeric eq (==)' warning at
# the "== PFSTATE_IDLE" line below.
next unless defined $k;
if ($k == PFSTATE_IDLE) {
$statestr .= 'I';
$num_idle++;
}
elsif ($k == PFSTATE_BUSY) {
$statestr .= 'B';
}
elsif ($k == PFSTATE_KILLED) {
$statestr .= 'K';
}
elsif ($k == PFSTATE_GOT_SIGCHLD) {
$statestr .= 'Z';
}
elsif ($k == PFSTATE_ERROR) {
$statestr .= 'E';
}
elsif ($k == PFSTATE_STARTING) {
$statestr .= 'S';
}
else {
$statestr .= '?';
}
}
info("prefork: child states: ".$statestr."\n");
# just kill off/add one at a time, to avoid swamping stuff and
# reacting too quickly; Apache emulation
if ($num_idle < $self->{min_idle}) {
if ($num_servers < $self->{max_children}) {
$self->need_to_add_server($num_idle);
} else {
info("prefork: server reached --max-children setting, consider raising it\n");
}
}
elsif ($num_idle > $self->{max_idle} && $num_servers > $self->{min_children}) {
$self->need_to_del_server($num_idle);
}
}
sub need_to_add_server {
my ($self, $num_idle) = @_;
my ($pid);
my $cur = ${$self->{cur_children_ref}};
$cur++;
dbg("prefork: adjust: increasing, not enough idle children ($num_idle < $self->{min_idle})");
$pid = main::spawn();
# servers will be started once main_server_poll() returns
#Added for bug 6304 to work on notifying administrators of poor parameters for spamd
info("prefork: adjust: %s idle children less than %s minimum idle children. Increasing spamd children: %s started.",$num_idle, $self->{min_idle}, $pid);
}
sub need_to_del_server {
my ($self, $num_idle) = @_;
my $cur = ${$self->{cur_children_ref}};
$cur--;
my $pid;
foreach my $k (keys %{$self->{kids}}) {
my $v = $self->{kids}->{$k};
if ($v == PFSTATE_IDLE)
{
# kill the highest; Apache emulation, exploits linux scheduler
# behaviour (and is predictable)
if (!defined $pid || $k > $pid) {
$pid = $k;
}
}
}
if (!defined $pid) {
# this should be impossible. assert it
die "prefork: oops! no idle kids in need_to_del_server?";
}
# warning: race condition if these two lines are the other way around.
# see bug 3983, comment 37 for details
$self->set_child_state ($pid, PFSTATE_KILLED);
if (!am_running_on_windows()) {
kill 'INT' => $pid;
} else {
my $sock = $self->{backchannel}->get_socket_for_child($pid);
# On win32 child cannot get a signal while reading socket
$sock->syswrite("P....\n");
kill 'INT' => $pid or warn "prefork: kill of child $pid failed: $!\n";
$self->{backchannel}->delete_socket_for_child($pid);
if (defined $sock && defined $sock->fileno()) {
$self->{backchannel}->remove_from_selector($sock);
}
$sock->close if $sock;
}
dbg("prefork: adjust: decreasing, too many idle children ($num_idle > $self->{max_idle}), killed $pid");
#Added for bug 6304 to work on notifying administrators of poor parameters for spamd
info("prefork: adjust: %s idle children more than %s maximum idle children. Decreasing spamd children: %s killed.",$num_idle, $self->{max_idle}, $pid);
}
sub vec_all {
my ($self, $bitsref, $fhs, $value) = @_;
my $ret = 0;
foreach my $fh (@{$fhs}) {
next unless defined $fh;
if (defined $value) {
vec($$bitsref, $fh, 1) = $value;
} else {
$ret |= vec($$bitsref, $fh, 1);
}
}
return $ret;
}
1;
__END__
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