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author | Eric Wong <e@80x24.org> | 2019-07-08 07:01:59 +0000 |
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committer | Eric Wong <e@80x24.org> | 2019-07-08 07:10:35 +0000 |
commit | 364d2e95439b00a211d007d93c5ba263b56c1ddf (patch) | |
tree | 857c1c9f69378ce9b4dc51dc0d736e4ff3f38ba6 /lib/PublicInbox/DS.pm | |
parent | 6d3644f5dd7c54fbee33be728f6735e4419cdc0d (diff) | |
download | public-inbox-364d2e95439b00a211d007d93c5ba263b56c1ddf.tar.gz |
While we're usually not stuck waiting on waitpid after seeing a pipe EOF or even triggering SIGPIPE in the process (e.g. git-http-backend) we're reading from, it MAY happen and we should be careful to never hang the daemon process on waitpid calls. v2: use "eq" for string comparison against 'DEFAULT'
Diffstat (limited to 'lib/PublicInbox/DS.pm')
-rw-r--r-- | lib/PublicInbox/DS.pm | 47 |
1 files changed, 46 insertions, 1 deletions
diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm index 586c47cd..51515bf6 100644 --- a/lib/PublicInbox/DS.pm +++ b/lib/PublicInbox/DS.pm @@ -16,7 +16,7 @@ package PublicInbox::DS; use strict; use bytes; -use POSIX (); +use POSIX qw(WNOHANG); use IO::Handle qw(); use Fcntl qw(SEEK_SET :DEFAULT); use Time::HiRes qw(clock_gettime CLOCK_MONOTONIC); @@ -38,6 +38,8 @@ use Carp qw(croak confess carp); require File::Spec; my $nextq = []; # queue for next_tick +my $WaitPids = []; # list of [ pid, callback, callback_arg ] +my $reap_timer; our ( %DescriptorMap, # fd (num) -> PublicInbox::DS object $Epoll, # Global epoll fd (or DSKQXS ref) @@ -64,6 +66,8 @@ Reset all state =cut sub Reset { %DescriptorMap = (); + $WaitPids = []; + $reap_timer = undef; @ToClose = (); $LoopTimeout = -1; # no timeout by default @Timers = (); @@ -215,7 +219,33 @@ sub RunTimers { return $timeout; } +# We can't use waitpid(-1) safely here since it can hit ``, system(), +# and other things. So we scan the $WaitPids list, which is hopefully +# not too big. +sub reap_pids { + my $tmp = $WaitPids; + $WaitPids = []; + $reap_timer = undef; + foreach my $ary (@$tmp) { + my ($pid, $cb, $arg) = @$ary; + my $ret = waitpid($pid, WNOHANG); + if ($ret == 0) { + push @$WaitPids, $ary; + } elsif ($cb) { + eval { $cb->($arg, $pid) }; + } + } + if (@$WaitPids) { + # we may not be donea, and we may miss our + $reap_timer = AddTimer(undef, 1, \&reap_pids); + } +} + +# reentrant SIGCHLD handler (since reap_pids is not reentrant) +sub enqueue_reap ($) { push @$nextq, \&reap_pids }; + sub EpollEventLoop { + local $SIG{CHLD} = \&enqueue_reap; while (1) { my @events; my $i; @@ -595,6 +625,21 @@ sub shutdn ($) { $self->close; } } + +# must be called with eval, PublicInbox::DS may not be loaded (see t/qspawn.t) +sub dwaitpid ($$$) { + my ($pid, $cb, $arg) = @_; + my $chld = $SIG{CHLD}; + if (defined($chld) && $chld eq \&enqueue_reap) { + push @$WaitPids, [ $pid, $cb, $arg ]; + + # We could've just missed our SIGCHLD, cover it, here: + requeue(\&reap_pids); + } else { + die "Not in EventLoop\n"; + } +} + package PublicInbox::DS::Timer; # [$abs_float_firetime, $coderef]; sub cancel { |