1 # This library is free software; you can redistribute it and/or modify
2 # it under the same terms as Perl itself.
4 # This license differs from the rest of public-inbox
6 # This is a fork of the unmaintained Danga::Socket (1.61) with
7 # significant changes. See Documentation/technical/ds.txt in our
10 # Do not expect this to be a stable API like Danga::Socket,
11 # but it will evolve to suite our needs and to take advantage of
12 # newer Linux and *BSD features.
13 # Bugs encountered were reported to bug-Danga-Socket@rt.cpan.org,
14 # fixed in Danga::Socket 1.62 and visible at:
15 # https://rt.cpan.org/Public/Dist/Display.html?Name=Danga-Socket
18 # sock: underlying socket
19 # rbuf: scalarref, usually undef
20 # wbuf: arrayref of coderefs or tmpio (autovivified))
21 # (tmpio = [ GLOB, offset, [ length ] ])
22 package PublicInbox::DS;
25 use parent qw(Exporter);
27 use POSIX qw(WNOHANG sigprocmask SIG_SETMASK);
29 use Fcntl qw(SEEK_SET :DEFAULT O_APPEND);
30 use Time::HiRes qw(clock_gettime CLOCK_MONOTONIC);
31 use Scalar::Util qw(blessed);
32 use PublicInbox::Syscall qw(:epoll);
33 use PublicInbox::Tmpfile;
34 use Errno qw(EAGAIN EINVAL);
35 use Carp qw(carp croak);
36 our @EXPORT_OK = qw(now msg_more dwaitpid add_timer);
38 my $nextq; # queue for next_tick
39 my $wait_pids; # list of [ pid, callback, callback_arg ]
40 my $later_queue; # list of callbacks to run at some later interval
41 my $EXPMAP; # fd -> idle_time
42 our $EXPTIME = 180; # 3 minutes
43 my ($later_timer, $reap_armed, $exp_timer);
44 my $ToClose; # sockets to close when event loop is done
46 %DescriptorMap, # fd (num) -> PublicInbox::DS object
47 $Epoll, # Global epoll fd (or DSKQXS ref)
48 $_io, # IO::Handle for Epoll
50 $PostLoopCallback, # subref to call at the end of each loop, if defined (global)
52 $LoopTimeout, # timeout of event loop in milliseconds
59 #####################################################################
60 ### C L A S S M E T H O D S
61 #####################################################################
63 =head2 C<< CLASS->Reset() >>
69 $in_loop = undef; # first in case DESTROY callbacks use this
71 $wait_pids = $later_queue = $reap_armed = undef;
73 $nextq = $ToClose = $later_timer = $exp_timer = undef;
74 $LoopTimeout = -1; # no timeout by default
77 $PostLoopCallback = undef;
79 $_io = undef; # closes real $Epoll FD
80 $Epoll = undef; # may call DSKQXS::DESTROY
83 =head2 C<< CLASS->SetLoopTimeout( $timeout ) >>
85 Set the loop timeout for the event loop to some value in milliseconds.
87 A timeout of 0 (zero) means poll forever. A timeout of -1 means poll and return
91 sub SetLoopTimeout { $LoopTimeout = $_[1] + 0 }
93 =head2 C<< PublicInbox::DS::add_timer( $seconds, $coderef, $arg) >>
95 Add a timer to occur $seconds from now. $seconds may be fractional, but timers
96 are not guaranteed to fire at the exact time you ask for.
99 sub add_timer ($$;@) {
100 my ($secs, $coderef, @args) = @_;
102 my $fire_time = now() + $secs;
104 my $timer = [$fire_time, $coderef, @args];
106 if (!@Timers || $fire_time >= $Timers[-1][0]) {
107 push @Timers, $timer;
111 # Now, where do we insert? (NOTE: this appears slow, algorithm-wise,
112 # but it was compared against calendar queues, heaps, naive push/sort,
113 # and a bunch of other versions, and found to be fastest with a large
114 # variety of datasets.)
115 for (my $i = 0; $i < @Timers; $i++) {
116 if ($Timers[$i][0] > $fire_time) {
117 splice(@Timers, $i, 0, $timer);
122 die "Shouldn't get here.";
125 # keeping this around in case we support other FD types for now,
126 # epoll_create1(EPOLL_CLOEXEC) requires Linux 2.6.27+...
127 sub set_cloexec ($) {
130 $_io = IO::Handle->new_from_fd($fd, 'r+') or return;
131 defined(my $fl = fcntl($_io, F_GETFD, 0)) or return;
132 fcntl($_io, F_SETFD, $fl | FD_CLOEXEC);
135 # caller sets return value to $Epoll
138 if (PublicInbox::Syscall::epoll_defined()) {
139 my $fd = epoll_create();
140 set_cloexec($fd) if (defined($fd) && $fd >= 0);
144 for (qw(DSKQXS DSPoll)) {
145 $cls = "PublicInbox::$_";
146 last if eval "require $cls";
148 $cls->import(qw(epoll_ctl epoll_wait));
153 =head2 C<< CLASS->EventLoop() >>
155 Start processing IO events. In most daemon programs this never exits. See
156 C<PostLoopCallback> below for how to exit the loop.
160 sub now () { clock_gettime(CLOCK_MONOTONIC) }
163 my $q = $nextq or return;
166 # we avoid "ref" on blessed refs to workaround a Perl 5.16.3 leak:
167 # https://rt.perl.org/Public/Bug/Display.html?id=114340
176 # runs timers and returns milliseconds for next one, or next event loop
180 return (($nextq || $ToClose) ? 0 : $LoopTimeout) unless @Timers;
185 while (@Timers && $Timers[0][0] <= $now) {
186 my $to_run = shift(@Timers);
187 $to_run->[1]->(@$to_run[2..$#$to_run]);
190 # timers may enqueue into nextq:
191 return 0 if ($nextq || $ToClose);
193 return $LoopTimeout unless @Timers;
195 # convert time to an even number of milliseconds, adding 1
196 # extra, otherwise floating point fun can occur and we'll
197 # call RunTimers like 20-30 times, each returning a timeout
198 # of 0.0000212 seconds
199 my $timeout = int(($Timers[0][0] - $now) * 1000) + 1;
201 # -1 is an infinite timeout, so prefer a real timeout
202 ($LoopTimeout < 0 || $LoopTimeout >= $timeout) ? $timeout : $LoopTimeout;
205 sub sig_setmask { sigprocmask(SIG_SETMASK, @_) or die "sigprocmask: $!" }
207 sub block_signals () {
208 my $oldset = POSIX::SigSet->new;
209 my $newset = POSIX::SigSet->new;
210 $newset->fillset or die "fillset: $!";
211 sig_setmask($newset, $oldset);
215 # We can't use waitpid(-1) safely here since it can hit ``, system(),
216 # and other things. So we scan the $wait_pids list, which is hopefully
217 # not too big. We keep $wait_pids small by not calling dwaitpid()
218 # until we've hit EOF when reading the stdout of the child.
222 my $tmp = $wait_pids or return;
224 my $oldset = block_signals();
225 foreach my $ary (@$tmp) {
226 my ($pid, $cb, $arg) = @$ary;
227 my $ret = waitpid($pid, WNOHANG);
229 push @$wait_pids, $ary; # autovivifies @$wait_pids
230 } elsif ($ret == $pid) {
232 eval { $cb->($arg, $pid) };
233 warn "E: dwaitpid($pid) in_loop: $@" if $@;
236 warn "waitpid($pid, WNOHANG) = $ret, \$!=$!, \$?=$?";
239 sig_setmask($oldset);
242 # reentrant SIGCHLD handler (since reap_pids is not reentrant)
243 sub enqueue_reap () { $reap_armed //= requeue(\&reap_pids) }
245 sub in_loop () { $in_loop }
247 # Internal function: run the post-event callback, send read events
248 # for pushed-back data, and close pending connections. returns 1
249 # if event loop should continue, or 0 to shut it all down.
250 sub PostEventLoop () {
251 # now we can close sockets that wanted to close during our event
252 # processing. (we didn't want to close them during the loop, as we
253 # didn't want fd numbers being reused and confused during the event
255 if (my $close_now = $ToClose) {
256 $ToClose = undef; # will be autovivified on push
257 @$close_now = map { fileno($_) } @$close_now;
259 # order matters, destroy expiry times, first:
260 delete @$EXPMAP{@$close_now};
262 # ->DESTROY methods may populate ToClose
263 delete @DescriptorMap{@$close_now};
266 # by default we keep running, unless a postloop callback cancels it
267 $PostLoopCallback ? $PostLoopCallback->(\%DescriptorMap) : 1;
271 $Epoll //= _InitPoller();
274 my $obj; # guard stack-not-refcounted w/ Carp + @DB::args
276 my $timeout = RunTimers();
278 # get up to 1000 events
279 epoll_wait($Epoll, 1000, $timeout, \@events);
280 for my $fd (@events) {
281 # it's possible epoll_wait returned many events, including some at the end
282 # that ones in the front triggered unregister-interest actions. if we
283 # can't find the %sock entry, it's because we're no longer interested
285 $obj = $DescriptorMap{$fd};
288 } while (PostEventLoop());
292 =head2 C<< CLASS->SetPostLoopCallback( CODEREF ) >>
294 Sets post loop callback function. Pass a subref and it will be
295 called every time the event loop finishes.
297 Return 1 (or any true value) from the sub to make the loop continue, 0 or false
300 The callback function will be passed two parameters: \%DescriptorMap
303 sub SetPostLoopCallback {
304 my ($class, $ref) = @_;
307 $PostLoopCallback = (defined $ref && ref $ref eq 'CODE') ? $ref : undef;
310 #####################################################################
311 ### PublicInbox::DS-the-object code
312 #####################################################################
314 =head2 OBJECT METHODS
316 =head2 C<< CLASS->new( $socket ) >>
318 Create a new PublicInbox::DS subclass object for the given I<socket> which will
319 react to events on it during the C<EventLoop>.
321 This is normally (always?) called from your subclass via:
323 $class->SUPER::new($socket);
327 my ($self, $sock, $ev) = @_;
328 $self->{sock} = $sock;
329 my $fd = fileno($sock);
331 $Epoll //= _InitPoller();
333 if (epoll_ctl($Epoll, EPOLL_CTL_ADD, $fd, $ev)) {
334 if ($! == EINVAL && ($ev & EPOLLEXCLUSIVE)) {
335 $ev &= ~EPOLLEXCLUSIVE;
338 die "EPOLL_CTL_ADD $self/$sock/$fd: $!";
340 croak("FD:$fd in use by $DescriptorMap{$fd} (for $self/$sock)")
341 if defined($DescriptorMap{$fd});
343 $DescriptorMap{$fd} = $self;
347 #####################################################################
348 ### I N S T A N C E M E T H O D S
349 #####################################################################
351 sub requeue ($) { push @$nextq, $_[0] } # autovivifies
353 =head2 C<< $obj->close >>
360 my $sock = delete $self->{sock} or return;
362 # we need to flush our write buffer, as there may
363 # be self-referential closures (sub { $client->close })
364 # preventing the object from being destroyed
365 delete $self->{wbuf};
367 # if we're using epoll, we have to remove this from our epoll fd so we stop getting
368 # notifications about it
369 my $fd = fileno($sock);
370 epoll_ctl($Epoll, EPOLL_CTL_DEL, $fd, 0) and
371 croak("EPOLL_CTL_DEL($self/$sock): $!");
373 # we explicitly don't delete from DescriptorMap here until we
374 # actually close the socket, as we might be in the middle of
375 # processing an epoll_wait/etc that returned hundreds of fds, one
376 # of which is not yet processed and is what we're closing. if we
377 # keep it in DescriptorMap, then the event harnesses can just
378 # looked at $pob->{sock} == undef and ignore it. but if it's an
379 # un-accounted for fd, then it (understandably) freak out a bit
380 # and emit warnings, thinking their state got off.
382 # defer closing the actual socket until the event loop is done
383 # processing this round of events. (otherwise we might reuse fds)
384 push @$ToClose, $sock; # autovivifies $ToClose
389 # portable, non-thread-safe sendfile emulation (no pread, yet)
390 sub send_tmpio ($$) {
391 my ($sock, $tmpio) = @_;
393 sysseek($tmpio->[0], $tmpio->[1], SEEK_SET) or return;
394 my $n = $tmpio->[2] // 65536;
395 $n = 65536 if $n > 65536;
396 defined(my $to_write = sysread($tmpio->[0], my $buf, $n)) or return;
398 while ($to_write > 0) {
399 if (defined(my $w = syswrite($sock, $buf, $to_write, $written))) {
403 return if $written == 0;
407 $tmpio->[1] += $written; # offset
408 $tmpio->[2] -= $written if defined($tmpio->[2]); # length
412 sub epbit ($$) { # (sock, default)
413 $_[0]->can('stop_SSL') ? PublicInbox::TLS::epollbit() : $_[1];
416 # returns 1 if done, 0 if incomplete
417 sub flush_write ($) {
419 my $sock = $self->{sock} or return;
420 my $wbuf = $self->{wbuf} or return 1;
423 while (my $bref = $wbuf->[0]) {
424 if (ref($bref) ne 'CODE') {
426 my $w = send_tmpio($sock, $bref); # bref is tmpio
432 } elsif ($! == EAGAIN) {
433 my $ev = epbit($sock, EPOLLOUT) or return $self->close;
434 epwait($sock, $ev | EPOLLONESHOT);
440 } else { #(ref($bref) eq 'CODE') {
442 my $before = scalar(@$wbuf);
445 # bref may be enqueueing more CODE to call (see accept_tls_step)
446 return 0 if (scalar(@$wbuf) > $before);
450 delete $self->{wbuf};
455 my ($self, $rbuf) = @_;
456 if ($$rbuf eq '') { # who knows how long till we can read again
457 delete $self->{rbuf};
459 $self->{rbuf} = $rbuf;
463 sub do_read ($$$;$) {
464 my ($self, $rbuf, $len, $off) = @_;
465 my $r = sysread(my $sock = $self->{sock}, $$rbuf, $len, $off // 0);
466 return ($r == 0 ? $self->close : $r) if defined $r;
467 # common for clients to break connections without warning,
468 # would be too noisy to log here:
470 my $ev = epbit($sock, EPOLLIN) or return $self->close;
471 epwait($sock, $ev | EPOLLONESHOT);
472 rbuf_idle($self, $rbuf);
479 # drop the socket if we hit unrecoverable errors on our system which
480 # require BOFH attention: ENOSPC, EFBIG, EIO, EMFILE, ENFILE...
487 # n.b.: use ->write/->read for this buffer to allow compatibility with
488 # PerlIO::mmap or PerlIO::scalar if needed
490 my ($self, $bref, $off) = @_;
491 my $fh = tmpfile('wbuf', $self->{sock}, O_APPEND) or
492 return drop($self, "tmpfile $!");
494 my $len = bytes::length($$bref) - $off;
495 $fh->write($$bref, $len, $off) or return drop($self, "write ($len): $!");
496 [ $fh, 0 ] # [1] = offset, [2] = length, not set by us
499 =head2 C<< $obj->write( $data ) >>
501 Write the specified data to the underlying handle. I<data> may be scalar,
502 scalar ref, code ref (to run when there).
503 Returns 1 if writes all went through, or 0 if there are writes in queue. If
504 it returns 1, caller should stop waiting for 'writable' events)
508 my ($self, $data) = @_;
510 # nobody should be writing to closed sockets, but caller code can
511 # do two writes within an event, have the first fail and
512 # disconnect the other side (whose destructor then closes the
513 # calling object, but it's still in a method), and then the
514 # now-dead object does its second write. that is this case. we
515 # just lie and say it worked. it'll be dead soon and won't be
517 my $sock = $self->{sock} or return 1;
519 my $bref = $ref ? $data : \$data;
520 my $wbuf = $self->{wbuf};
521 if ($wbuf && scalar(@$wbuf)) { # already buffering, can't write more...
522 if ($ref eq 'CODE') {
525 my $tmpio = $wbuf->[-1];
526 if ($tmpio && !defined($tmpio->[2])) { # append to tmp file buffer
527 $tmpio->[0]->print($$bref) or return drop($self, "print: $!");
529 my $tmpio = tmpio($self, $bref, 0) or return 0;
534 } elsif ($ref eq 'CODE') {
538 my $to_write = bytes::length($$bref);
539 my $written = syswrite($sock, $$bref, $to_write);
541 if (defined $written) {
542 return 1 if $written == $to_write;
543 requeue($self); # runs: event_step -> flush_write
544 } elsif ($! == EAGAIN) {
545 my $ev = epbit($sock, EPOLLOUT) or return $self->close;
546 epwait($sock, $ev | EPOLLONESHOT);
552 # deal with EAGAIN or partial write:
553 my $tmpio = tmpio($self, $bref, $written) or return 0;
555 # wbuf may be an empty array if we're being called inside
556 # ->flush_write via CODE bref:
557 push @{$self->{wbuf}}, $tmpio; # autovivifies
562 use constant MSG_MORE => ($^O eq 'linux') ? 0x8000 : 0;
566 my $sock = $self->{sock} or return 1;
567 my $wbuf = $self->{wbuf};
569 if (MSG_MORE && (!defined($wbuf) || !scalar(@$wbuf)) &&
570 !$sock->can('stop_SSL')) {
571 my $n = send($sock, $_[1], MSG_MORE);
573 my $nlen = bytes::length($_[1]) - $n;
574 return 1 if $nlen == 0; # all done!
575 # queue up the unwritten substring:
576 my $tmpio = tmpio($self, \($_[1]), $n) or return 0;
577 push @{$self->{wbuf}}, $tmpio; # autovivifies
578 epwait($sock, EPOLLOUT|EPOLLONESHOT);
583 # don't redispatch into NNTPdeflate::write
584 PublicInbox::DS::write($self, \($_[1]));
588 my ($sock, $ev) = @_;
589 epoll_ctl($Epoll, EPOLL_CTL_MOD, fileno($sock), $ev) and
590 croak("EPOLL_CTL_MOD($sock): $!");
593 # return true if complete, false if incomplete (or failure)
594 sub accept_tls_step ($) {
596 my $sock = $self->{sock} or return;
597 return 1 if $sock->accept_SSL;
598 return $self->close if $! != EAGAIN;
599 my $ev = PublicInbox::TLS::epollbit() or return $self->close;
600 epwait($sock, $ev | EPOLLONESHOT);
601 unshift(@{$self->{wbuf}}, \&accept_tls_step); # autovivifies
605 # return true if complete, false if incomplete (or failure)
606 sub shutdn_tls_step ($) {
608 my $sock = $self->{sock} or return;
609 return $self->close if $sock->stop_SSL(SSL_fast_shutdown => 1);
610 return $self->close if $! != EAGAIN;
611 my $ev = PublicInbox::TLS::epollbit() or return $self->close;
612 epwait($sock, $ev | EPOLLONESHOT);
613 unshift(@{$self->{wbuf}}, \&shutdn_tls_step); # autovivifies
617 # don't bother with shutdown($sock, 2), we don't fork+exec w/o CLOEXEC
618 # or fork w/o exec, so no inadvertent socket sharing
621 my $sock = $self->{sock} or return;
622 if ($sock->can('stop_SSL')) {
623 shutdn_tls_step($self);
629 sub dwaitpid ($;$$) {
630 my ($pid, $cb, $arg) = @_;
632 push @$wait_pids, [ $pid, $cb, $arg ];
633 # We could've just missed our SIGCHLD, cover it, here:
636 my $ret = waitpid($pid, 0);
639 eval { $cb->($arg, $pid) };
640 carp "E: dwaitpid($pid) !in_loop: $@" if $@;
643 carp "waitpid($pid, 0) = $ret, \$!=$!, \$?=$?";
649 my $run = $later_queue or return;
650 $later_timer = $later_queue = undef;
655 push @$later_queue, $_[0]; # autovivifies @$later_queue
656 $later_timer //= add_timer(60, \&_run_later);
662 my $old = $now - $exp;
664 while (my ($fd, $idle_at) = each %$EXPMAP) {
665 if ($idle_at < $old) {
666 my $ds_obj = $DescriptorMap{$fd};
667 $new{$fd} = $idle_at if !$ds_obj->shutdn;
669 $new{$fd} = $idle_at;
673 $exp_timer = scalar(keys %new) ? later(\&expire_old) : undef;
676 sub update_idle_time {
678 my $sock = $self->{sock} or return;
679 $EXPMAP->{fileno($sock)} = now();
680 $exp_timer //= later(\&expire_old);
684 my ($self, $now) = @_;
685 my $sock = $self->{sock} or return;
686 my $idle_at = $EXPMAP->{fileno($sock)} or return;
687 ($idle_at + $EXPTIME) > $now;
692 =head1 AUTHORS (Danga::Socket)
694 Brad Fitzpatrick <brad@danga.com> - author
696 Michael Granger <ged@danga.com> - docs, testing
698 Mark Smith <junior@danga.com> - contributor, heavy user, testing
700 Matt Sergeant <matt@sergeant.org> - kqueue support, docs, timers, other bits