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 (for now) unmaintained Danga::Socket 1.61.
7 # Unused features will be removed, and updates will be made to take
8 # advantage of newer kernels.
10 # API changes to diverge from Danga::Socket will happen to better
11 # accomodate new features and improve scalability. Do not expect
12 # this to be a stable API like Danga::Socket.
13 # Bugs encountered (and likely fixed) are reported to
14 # bug-Danga-Socket@rt.cpan.org and visible at:
15 # https://rt.cpan.org/Public/Dist/Display.html?Name=Danga-Socket
16 package PublicInbox::DS;
19 use POSIX qw(WNOHANG);
21 use Fcntl qw(SEEK_SET :DEFAULT);
22 use Time::HiRes qw(clock_gettime CLOCK_MONOTONIC);
23 use parent qw(Exporter);
24 our @EXPORT_OK = qw(now msg_more);
27 use Scalar::Util qw(blessed);
29 use PublicInbox::Syscall qw(:epoll);
30 use PublicInbox::Tmpfile;
32 use fields ('sock', # underlying socket
33 'rbuf', # scalarref, usually undef
34 'wbuf', # arrayref of coderefs or GLOB refs
35 'wbuf_off', # offset into first element of wbuf to start writing at
38 use Errno qw(EAGAIN EINVAL);
39 use Carp qw(croak confess carp);
42 my $nextq; # queue for next_tick
43 my $WaitPids; # list of [ pid, callback, callback_arg ]
46 %DescriptorMap, # fd (num) -> PublicInbox::DS object
47 $Epoll, # Global epoll fd (or DSKQXS ref)
48 $_io, # IO::Handle for Epoll
49 @ToClose, # sockets to close when event loop is done
51 $PostLoopCallback, # subref to call at the end of each loop, if defined (global)
53 $LoopTimeout, # timeout of event loop in milliseconds
54 $DoneInit, # if we've done the one-time module init yet
61 #####################################################################
62 ### C L A S S M E T H O D S
63 #####################################################################
65 =head2 C<< CLASS->Reset() >>
76 $LoopTimeout = -1; # no timeout by default
79 $PostLoopCallback = undef;
82 $_io = undef; # closes real $Epoll FD
83 $Epoll = undef; # may call DSKQXS::DESTROY
85 *EventLoop = *FirstTimeEventLoop;
88 =head2 C<< CLASS->SetLoopTimeout( $timeout ) >>
90 Set the loop timeout for the event loop to some value in milliseconds.
92 A timeout of 0 (zero) means poll forever. A timeout of -1 means poll and return
97 return $LoopTimeout = $_[1] + 0;
100 =head2 C<< CLASS->AddTimer( $seconds, $coderef ) >>
102 Add a timer to occur $seconds from now. $seconds may be fractional, but timers
103 are not guaranteed to fire at the exact time you ask for.
105 Returns a timer object which you can call C<< $timer->cancel >> on if you need to.
109 my ($class, $secs, $coderef) = @_;
111 my $fire_time = now() + $secs;
113 my $timer = bless [$fire_time, $coderef], "PublicInbox::DS::Timer";
115 if (!@Timers || $fire_time >= $Timers[-1][0]) {
116 push @Timers, $timer;
120 # Now, where do we insert? (NOTE: this appears slow, algorithm-wise,
121 # but it was compared against calendar queues, heaps, naive push/sort,
122 # and a bunch of other versions, and found to be fastest with a large
123 # variety of datasets.)
124 for (my $i = 0; $i < @Timers; $i++) {
125 if ($Timers[$i][0] > $fire_time) {
126 splice(@Timers, $i, 0, $timer);
131 die "Shouldn't get here.";
134 # keeping this around in case we support other FD types for now,
135 # epoll_create1(EPOLL_CLOEXEC) requires Linux 2.6.27+...
136 sub set_cloexec ($) {
139 $_io = IO::Handle->new_from_fd($fd, 'r+') or return;
140 defined(my $fl = fcntl($_io, F_GETFD, 0)) or return;
141 fcntl($_io, F_SETFD, $fl | FD_CLOEXEC);
149 if (PublicInbox::Syscall::epoll_defined()) {
150 $Epoll = epoll_create();
151 set_cloexec($Epoll) if (defined($Epoll) && $Epoll >= 0);
154 for (qw(DSKQXS DSPoll)) {
155 $cls = "PublicInbox::$_";
156 last if eval "require $cls";
158 $cls->import(qw(epoll_ctl epoll_wait));
161 *EventLoop = *EpollEventLoop;
164 =head2 C<< CLASS->EventLoop() >>
166 Start processing IO events. In most daemon programs this never exits. See
167 C<PostLoopCallback> below for how to exit the loop.
170 sub FirstTimeEventLoop {
178 sub now () { clock_gettime(CLOCK_MONOTONIC) }
184 # we avoid "ref" on blessed refs to workaround a Perl 5.16.3 leak:
185 # https://rt.perl.org/Public/Bug/Display.html?id=114340
194 # runs timers and returns milliseconds for next one, or next event loop
198 return ((@$nextq || @ToClose) ? 0 : $LoopTimeout) unless @Timers;
203 while (@Timers && $Timers[0][0] <= $now) {
204 my $to_run = shift(@Timers);
205 $to_run->[1]->($now) if $to_run->[1];
208 # timers may enqueue into nextq:
209 return 0 if (@$nextq || @ToClose);
211 return $LoopTimeout unless @Timers;
213 # convert time to an even number of milliseconds, adding 1
214 # extra, otherwise floating point fun can occur and we'll
215 # call RunTimers like 20-30 times, each returning a timeout
216 # of 0.0000212 seconds
217 my $timeout = int(($Timers[0][0] - $now) * 1000) + 1;
219 # -1 is an infinite timeout, so prefer a real timeout
220 return $timeout if $LoopTimeout == -1;
222 # otherwise pick the lower of our regular timeout and time until
224 return $LoopTimeout if $LoopTimeout < $timeout;
228 # We can't use waitpid(-1) safely here since it can hit ``, system(),
229 # and other things. So we scan the $WaitPids list, which is hopefully
235 foreach my $ary (@$tmp) {
236 my ($pid, $cb, $arg) = @$ary;
237 my $ret = waitpid($pid, WNOHANG);
239 push @$WaitPids, $ary;
241 eval { $cb->($arg, $pid) };
245 # we may not be donea, and we may miss our
246 $reap_timer = AddTimer(undef, 1, \&reap_pids);
250 # reentrant SIGCHLD handler (since reap_pids is not reentrant)
251 sub enqueue_reap ($) { push @$nextq, \&reap_pids };
258 my $timeout = RunTimers();
260 # get up to 1000 events
261 my $evcount = epoll_wait($Epoll, 1000, $timeout, \@events);
262 for ($i=0; $i<$evcount; $i++) {
263 # it's possible epoll_wait returned many events, including some at the end
264 # that ones in the front triggered unregister-interest actions. if we
265 # can't find the %sock entry, it's because we're no longer interested
267 $DescriptorMap{$events[$i]->[0]}->event_step;
269 return unless PostEventLoop();
273 =head2 C<< CLASS->SetPostLoopCallback( CODEREF ) >>
275 Sets post loop callback function. Pass a subref and it will be
276 called every time the event loop finishes.
278 Return 1 (or any true value) from the sub to make the loop continue, 0 or false
281 The callback function will be passed two parameters: \%DescriptorMap
284 sub SetPostLoopCallback {
285 my ($class, $ref) = @_;
288 $PostLoopCallback = (defined $ref && ref $ref eq 'CODE') ? $ref : undef;
291 # Internal function: run the post-event callback, send read events
292 # for pushed-back data, and close pending connections. returns 1
293 # if event loop should continue, or 0 to shut it all down.
295 # now we can close sockets that wanted to close during our event processing.
296 # (we didn't want to close them during the loop, as we didn't want fd numbers
297 # being reused and confused during the event loop)
298 delete($DescriptorMap{fileno($_)}) for @ToClose;
299 @ToClose = (); # let refcounting drop everything all at once
301 # by default we keep running, unless a postloop callback (either per-object
302 # or global) cancels it
303 my $keep_running = 1;
305 # now we're at the very end, call callback if defined
306 if (defined $PostLoopCallback) {
307 $keep_running &&= $PostLoopCallback->(\%DescriptorMap);
310 return $keep_running;
313 #####################################################################
314 ### PublicInbox::DS-the-object code
315 #####################################################################
317 =head2 OBJECT METHODS
319 =head2 C<< CLASS->new( $socket ) >>
321 Create a new PublicInbox::DS subclass object for the given I<socket> which will
322 react to events on it during the C<EventLoop>.
324 This is normally (always?) called from your subclass via:
326 $class->SUPER::new($socket);
330 my ($self, $sock, $ev) = @_;
331 $self = fields::new($self) unless ref $self;
333 $self->{sock} = $sock;
334 my $fd = fileno($sock);
336 Carp::cluck("undef sock and/or fd in PublicInbox::DS->new. sock=" . ($sock || "") . ", fd=" . ($fd || ""))
341 if (epoll_ctl($Epoll, EPOLL_CTL_ADD, $fd, $ev)) {
342 if ($! == EINVAL && ($ev & EPOLLEXCLUSIVE)) {
343 $ev &= ~EPOLLEXCLUSIVE;
346 die "couldn't add epoll watch for $fd: $!\n";
348 Carp::cluck("PublicInbox::DS::new blowing away existing descriptor map for fd=$fd ($DescriptorMap{$fd})")
349 if $DescriptorMap{$fd};
351 $DescriptorMap{$fd} = $self;
356 #####################################################################
357 ### I N S T A N C E M E T H O D S
358 #####################################################################
360 sub requeue ($) { push @$nextq, $_[0] }
362 =head2 C<< $obj->close >>
369 my $sock = delete $self->{sock} or return;
371 # we need to flush our write buffer, as there may
372 # be self-referential closures (sub { $client->close })
373 # preventing the object from being destroyed
374 delete $self->{wbuf};
376 # if we're using epoll, we have to remove this from our epoll fd so we stop getting
377 # notifications about it
378 my $fd = fileno($sock);
379 epoll_ctl($Epoll, EPOLL_CTL_DEL, $fd, 0) and
380 confess("EPOLL_CTL_DEL: $!");
382 # we explicitly don't delete from DescriptorMap here until we
383 # actually close the socket, as we might be in the middle of
384 # processing an epoll_wait/etc that returned hundreds of fds, one
385 # of which is not yet processed and is what we're closing. if we
386 # keep it in DescriptorMap, then the event harnesses can just
387 # looked at $pob->{sock} == undef and ignore it. but if it's an
388 # un-accounted for fd, then it (understandably) freak out a bit
389 # and emit warnings, thinking their state got off.
391 # defer closing the actual socket until the event loop is done
392 # processing this round of events. (otherwise we might reuse fds)
393 push @ToClose, $sock;
398 # portable, non-thread-safe sendfile emulation (no pread, yet)
399 sub psendfile ($$$) {
400 my ($sock, $fh, $off) = @_;
402 seek($fh, $$off, SEEK_SET) or return;
403 defined(my $to_write = read($fh, my $buf, 16384)) or return;
405 while ($to_write > 0) {
406 if (defined(my $w = syswrite($sock, $buf, $to_write, $written))) {
410 return if $written == 0;
418 sub epbit ($$) { # (sock, default)
419 ref($_[0]) eq 'IO::Socket::SSL' ? PublicInbox::TLS::epollbit() : $_[1];
422 # returns 1 if done, 0 if incomplete
423 sub flush_write ($) {
425 my $wbuf = $self->{wbuf} or return 1;
426 my $sock = $self->{sock};
429 while (my $bref = $wbuf->[0]) {
430 if (ref($bref) ne 'CODE') {
431 my $off = delete($self->{wbuf_off}) // 0;
433 my $w = psendfile($sock, $bref, \$off);
439 } elsif ($! == EAGAIN) {
440 epwait($sock, epbit($sock, EPOLLOUT) | EPOLLONESHOT);
441 $self->{wbuf_off} = $off;
447 } else { #($ref eq 'CODE') {
449 my $before = scalar(@$wbuf);
452 # bref may be enqueueing more CODE to call (see accept_tls_step)
453 return 0 if (scalar(@$wbuf) > $before);
457 delete $self->{wbuf};
462 my ($self, $rbuf) = @_;
463 if ($$rbuf eq '') { # who knows how long till we can read again
464 delete $self->{rbuf};
466 $self->{rbuf} = $rbuf;
470 sub do_read ($$$;$) {
471 my ($self, $rbuf, $len, $off) = @_;
472 my $r = sysread(my $sock = $self->{sock}, $$rbuf, $len, $off // 0);
473 return ($r == 0 ? $self->close : $r) if defined $r;
474 # common for clients to break connections without warning,
475 # would be too noisy to log here:
477 epwait($sock, epbit($sock, EPOLLIN) | EPOLLONESHOT);
478 rbuf_idle($self, $rbuf);
485 # drop the socket if we hit unrecoverable errors on our system which
486 # require BOFH attention: ENOSPC, EFBIG, EIO, EMFILE, ENFILE...
493 # n.b.: use ->write/->read for this buffer to allow compatibility with
494 # PerlIO::mmap or PerlIO::scalar if needed
496 my ($self, $bref, $off) = @_;
497 my $fh = tmpfile('wbuf', $self->{sock}, 1) or
498 return drop($self, "tmpfile $!");
500 my $len = bytes::length($$bref) - $off;
501 $fh->write($$bref, $len, $off) or return drop($self, "write ($len): $!");
505 =head2 C<< $obj->write( $data ) >>
507 Write the specified data to the underlying handle. I<data> may be scalar,
508 scalar ref, code ref (to run when there).
509 Returns 1 if writes all went through, or 0 if there are writes in queue. If
510 it returns 1, caller should stop waiting for 'writable' events)
514 my ($self, $data) = @_;
516 # nobody should be writing to closed sockets, but caller code can
517 # do two writes within an event, have the first fail and
518 # disconnect the other side (whose destructor then closes the
519 # calling object, but it's still in a method), and then the
520 # now-dead object does its second write. that is this case. we
521 # just lie and say it worked. it'll be dead soon and won't be
523 my $sock = $self->{sock} or return 1;
525 my $bref = $ref ? $data : \$data;
526 my $wbuf = $self->{wbuf};
527 if ($wbuf && scalar(@$wbuf)) { # already buffering, can't write more...
528 if ($ref eq 'CODE') {
531 my $last = $wbuf->[-1];
532 if (ref($last) eq 'GLOB') { # append to tmp file buffer
533 $last->print($$bref) or return drop($self, "print: $!");
535 my $tmpio = tmpio($self, $bref, 0) or return 0;
540 } elsif ($ref eq 'CODE') {
544 my $to_write = bytes::length($$bref);
545 my $written = syswrite($sock, $$bref, $to_write);
547 if (defined $written) {
548 return 1 if $written == $to_write;
549 requeue($self); # runs: event_step -> flush_write
550 } elsif ($! == EAGAIN) {
551 epwait($sock, epbit($sock, EPOLLOUT) | EPOLLONESHOT);
557 # deal with EAGAIN or partial write:
558 my $tmpio = tmpio($self, $bref, $written) or return 0;
560 # wbuf may be an empty array if we're being called inside
561 # ->flush_write via CODE bref:
562 push @{$self->{wbuf} ||= []}, $tmpio;
567 use constant MSG_MORE => ($^O eq 'linux') ? 0x8000 : 0;
571 my $sock = $self->{sock} or return 1;
573 if (MSG_MORE && !$self->{wbuf} && ref($sock) ne 'IO::Socket::SSL') {
574 my $n = send($sock, $_[1], MSG_MORE);
576 my $nlen = bytes::length($_[1]) - $n;
577 return 1 if $nlen == 0; # all done!
578 # queue up the unwritten substring:
579 my $tmpio = tmpio($self, \($_[1]), $n) or return 0;
580 $self->{wbuf} = [ $tmpio ];
581 epwait($sock, EPOLLOUT|EPOLLONESHOT);
586 # don't redispatch into NNTPdeflate::write
587 PublicInbox::DS::write($self, \($_[1]));
591 my ($sock, $ev) = @_;
592 epoll_ctl($Epoll, EPOLL_CTL_MOD, fileno($sock), $ev) and
593 confess("EPOLL_CTL_MOD $!");
596 # return true if complete, false if incomplete (or failure)
597 sub accept_tls_step ($) {
599 my $sock = $self->{sock} or return;
600 return 1 if $sock->accept_SSL;
601 return $self->close if $! != EAGAIN;
602 epwait($sock, PublicInbox::TLS::epollbit() | EPOLLONESHOT);
603 unshift @{$self->{wbuf} ||= []}, \&accept_tls_step;
607 # return true if complete, false if incomplete (or failure)
608 sub shutdn_tls_step ($) {
610 my $sock = $self->{sock} or return;
611 return $self->close if $sock->stop_SSL(SSL_fast_shutdown => 1);
612 return $self->close if $! != EAGAIN;
613 epwait($sock, PublicInbox::TLS::epollbit() | EPOLLONESHOT);
614 unshift @{$self->{wbuf} ||= []}, \&shutdn_tls_step;
618 # don't bother with shutdown($sock, 2), we don't fork+exec w/o CLOEXEC
619 # or fork w/o exec, so no inadvertant socket sharing
622 my $sock = $self->{sock} or return;
623 if (ref($sock) eq 'IO::Socket::SSL') {
624 shutdn_tls_step($self);
630 # must be called with eval, PublicInbox::DS may not be loaded (see t/qspawn.t)
632 my ($pid, $cb, $arg) = @_;
634 push @$WaitPids, [ $pid, $cb, $arg ];
636 # We could've just missed our SIGCHLD, cover it, here:
637 requeue(\&reap_pids);
639 die "Not in EventLoop\n";
643 package PublicInbox::DS::Timer;
644 # [$abs_float_firetime, $coderef];
651 =head1 AUTHORS (Danga::Socket)
653 Brad Fitzpatrick <brad@danga.com> - author
655 Michael Granger <ged@danga.com> - docs, testing
657 Mark Smith <junior@danga.com> - contributor, heavy user, testing
659 Matt Sergeant <matt@sergeant.org> - kqueue support, docs, timers, other bits