1 # Copyright (C) 2020-2021 all contributors <meta@public-inbox.org>
2 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
4 # base class for remote IPC calls and workqueues, requires Storable or Sereal
5 # - ipc_do and ipc_worker_* is for a single worker/producer and uses pipes
6 # - wq_do and wq_worker* is for a single producer and multiple workers,
7 # using SOCK_SEQPACKET for work distribution
8 # use ipc_do when you need work done on a certain process
9 # use wq_do when your work can be done on any idle worker
10 package PublicInbox::IPC;
13 use Carp qw(confess croak);
14 use PublicInbox::DS qw(dwaitpid);
15 use PublicInbox::Spawn;
16 use PublicInbox::OnDestroy;
17 use PublicInbox::WQWorker;
18 use Socket qw(AF_UNIX MSG_EOR SOCK_STREAM);
19 use Errno qw(EMSGSIZE);
20 my $SEQPACKET = eval { Socket::SOCK_SEQPACKET() }; # portable enough?
21 use constant PIPE_BUF => $^O eq 'linux' ? 4096 : POSIX::_POSIX_PIPE_BUF();
22 my $WQ_MAX_WORKERS = 4096;
24 # ->imports at BEGIN turns sereal_*_with_object into custom ops on 5.14+
25 # and eliminate method call overhead
28 require Sereal::Encoder;
29 require Sereal::Decoder;
30 Sereal::Encoder->import('sereal_encode_with_object');
31 Sereal::Decoder->import('sereal_decode_with_object');
32 ($enc, $dec) = (Sereal::Encoder->new, Sereal::Decoder->new);
36 if ($enc && $dec) { # should be custom ops
37 *freeze = sub ($) { sereal_encode_with_object $enc, $_[0] };
38 *thaw = sub ($) { sereal_decode_with_object $dec, $_[0], my $ret };
40 eval { # some distros have Storable as a separate package from Perl
42 Storable->import(qw(freeze thaw));
44 } // warn("Storable (part of Perl) missing: $@\n");
47 my $recv_cmd = PublicInbox::Spawn->can('recv_cmd4');
48 my $send_cmd = PublicInbox::Spawn->can('send_cmd4') // do {
49 require PublicInbox::CmdIPC4;
50 $recv_cmd //= PublicInbox::CmdIPC4->can('recv_cmd4');
51 PublicInbox::CmdIPC4->can('send_cmd4');
56 defined(my $len = <$r>) or return;
57 chop($len) eq "\n" or croak "no LF byte in $len";
58 defined(my $n = read($r, my $buf, $len)) or croak "read error: $!";
59 $n == $len or croak "short read: $n != $len";
65 my $buf = freeze($ref);
66 length($buf) . "\n" . $buf;
71 print $w _pack_rec($ref) or croak "print: $!";
74 sub ipc_return ($$$) {
75 my ($w, $ret, $exc) = @_;
76 _send_rec($w, $exc ? bless(\$exc, 'PublicInbox::IPC::Die') : $ret);
79 sub ipc_worker_loop ($$$) {
80 my ($self, $r_req, $w_res) = @_;
81 my ($rec, $wantarray, $sub, @args);
83 while ($rec = _get_rec($r_req)) {
84 ($wantarray, $sub, @args) = @$rec;
85 # no waiting if client doesn't care,
86 # this is the overwhelmingly likely case
87 if (!defined($wantarray)) {
88 eval { $self->$sub(@args) };
89 warn "$$ die: $@ (from nowait $sub)\n" if $@;
90 } elsif ($wantarray) {
91 my @ret = eval { $self->$sub(@args) };
92 ipc_return($w_res, \@ret, $@);
93 } else { # '' => wantscalar
94 my $ret = eval { $self->$sub(@args) };
95 ipc_return($w_res, \$ret, $@);
100 # starts a worker if Sereal or Storable is installed
101 sub ipc_worker_spawn {
102 my ($self, $ident, $oldset) = @_;
103 return unless $enc; # no Sereal or Storable
104 return if ($self->{-ipc_ppid} // -1) == $$; # idempotent
105 delete(@$self{qw(-ipc_req -ipc_res -ipc_ppid -ipc_pid)});
106 pipe(my ($r_req, $w_req)) or die "pipe: $!";
107 pipe(my ($r_res, $w_res)) or die "pipe: $!";
108 my $sigset = $oldset // PublicInbox::DS::block_signals();
109 $self->ipc_atfork_prepare;
110 my $seed = rand(0xffffffff);
111 my $pid = fork // die "fork: $!";
114 eval { PublicInbox::DS->Reset };
115 delete @$self{qw(-wq_s1 -wq_s2 -wq_workers -wq_ppid)};
116 $w_req = $r_res = undef;
117 $w_res->autoflush(1);
118 $SIG{$_} = 'IGNORE' for (qw(TERM INT QUIT));
120 PublicInbox::DS::sig_setmask($sigset);
121 # ensure we properly exit even if warn() dies:
122 my $end = PublicInbox::OnDestroy->new($$, sub { exit(!!$@) });
124 my $on_destroy = $self->ipc_atfork_child;
126 ipc_worker_loop($self, $r_req, $w_res);
128 die "worker $ident PID:$$ died: $@\n" if $@;
129 undef $end; # trigger exit
131 PublicInbox::DS::sig_setmask($sigset) unless $oldset;
132 $r_req = $w_res = undef;
133 $w_req->autoflush(1);
134 $self->{-ipc_req} = $w_req;
135 $self->{-ipc_res} = $r_res;
136 $self->{-ipc_ppid} = $$;
137 $self->{-ipc_pid} = $pid;
140 sub ipc_worker_reap { # dwaitpid callback
141 my ($self, $pid) = @_;
143 # TERM(15) is our default exit signal, PIPE(13) is likely w/ pager
145 warn "PID:$pid died with \$?=$?\n" if $s != 15 && $s != 13;
150 my $pids = delete $self->{"-wq_old_pids.$$"} or return;
151 dwaitpid($_, \&ipc_worker_reap, $self) for @$pids;
154 # for base class, override in sub classes
155 sub ipc_atfork_prepare {}
157 sub wq_atexit_child {}
159 sub ipc_atfork_child {
161 my $io = delete($self->{-ipc_atfork_child_close}) or return;
166 # idempotent, can be called regardless of whether worker is active or not
167 sub ipc_worker_stop {
169 my ($pid, $ppid) = delete(@$self{qw(-ipc_pid -ipc_ppid)});
170 my ($w_req, $r_res) = delete(@$self{qw(-ipc_req -ipc_res)});
171 if (!$w_req && !$r_res) {
172 die "unexpected PID:$pid without IPC pipes" if $pid;
175 die 'no PID with IPC pipes' unless $pid;
176 $w_req = $r_res = undef;
178 return if $$ != $ppid;
179 dwaitpid($pid, \&ipc_worker_reap, $self);
182 # use this if we have multiple readers reading curl or "pigz -dc"
183 # and writing to the same store
186 require PublicInbox::Lock;
187 $self->{-ipc_lock} //= bless { lock_path => $f }, 'PublicInbox::Lock'
190 sub ipc_async_wait ($$) {
191 my ($self, $max) = @_; # max == -1 to wait for all
192 my $aif = $self->{-async_inflight} or return;
193 my $r_res = $self->{-ipc_res} or die 'BUG: no ipc_res';
194 while (my ($sub, $bytes, $cb, $cb_arg) = splice(@$aif, 0, 4)) {
195 my $ret = _get_rec($r_res) //
196 die "no response on $sub (req.size=$bytes)";
197 $self->{-async_inflight_bytes} -= $bytes;
199 eval { $cb->($cb_arg, $ret) };
200 warn "E: $sub callback error: $@\n" if $@;
201 return if --$max == 0;
205 # call $self->$sub(@args), on a worker if ipc_worker_spawn was used
207 my ($self, $sub, @args) = @_;
208 if (my $w_req = $self->{-ipc_req}) { # run in worker
209 my $ipc_lock = $self->{-ipc_lock};
210 my $lock = $ipc_lock ? $ipc_lock->lock_for_scope : undef;
211 if (defined(wantarray)) {
212 my $r_res = $self->{-ipc_res} or die 'BUG: no ipc_res';
213 ipc_async_wait($self, -1);
214 _send_rec($w_req, [ wantarray, $sub, @args ]);
215 my $ret = _get_rec($r_res) // die "no response on $sub";
216 die $$ret if ref($ret) eq 'PublicInbox::IPC::Die';
217 wantarray ? @$ret : $$ret;
218 } else { # likely, fire-and-forget into pipe
219 _send_rec($w_req, [ undef , $sub, @args ]);
221 } else { # run locally
227 my ($self, $sub, $sub_args, $cb, $cb_arg) = @_;
228 if (my $w_req = $self->{-ipc_req}) { # run in worker
229 my $rec = _pack_rec([ 1, $sub, @$sub_args ]);
230 my $cur_bytes = \($self->{-async_inflight_bytes} //= 0);
231 while (($$cur_bytes + length($rec)) > PIPE_BUF) {
232 ipc_async_wait($self, 1);
234 my $ipc_lock = $self->{-ipc_lock};
235 my $lock = $ipc_lock ? $ipc_lock->lock_for_scope : undef;
236 print $w_req $rec or croak "print: $!";
237 $$cur_bytes += length($rec);
238 push @{$self->{-async_inflight}},
239 $sub, length($rec), $cb, $cb_arg;
241 my $ret = [ eval { $self->$sub(@$sub_args) } ];
243 $ret = ( bless(\$exc, 'PublicInbox::IPC::Die') );
245 eval { $cb->($cb_arg, $ret) };
246 warn "E: $sub callback error: $@\n" if $@;
250 # needed when there's multiple IPC workers and the parent forking
251 # causes newer siblings to inherit older siblings sockets
252 sub ipc_sibling_atfork_child {
254 my ($pid, undef) = delete(@$self{qw(-ipc_pid -ipc_ppid)});
255 delete(@$self{qw(-ipc_req -ipc_res)});
256 $pid == $$ and die "BUG: $$ ipc_atfork_child called on itself";
260 my ($self, $s2, $len, $full_stream) = @_;
261 my @fds = $recv_cmd->($s2, my $buf, $len);
262 return if scalar(@fds) && !defined($fds[0]);
263 my $n = length($buf) or return 0;
266 if (open(my $cmdfh, '+<&=', $fd)) {
267 $self->{$nfd++} = $cmdfh;
268 $cmdfh->autoflush(1);
270 die "$$ open(+<&=$fd) (FD:$nfd): $!";
273 while ($full_stream && $n < $len) {
274 my $r = sysread($s2, $buf, $len - $n, $n) // croak "read: $!";
275 croak "read EOF after $n/$len bytes" if $r == 0;
278 # Sereal dies on truncated data, Storable returns undef
279 my $args = thaw($buf) // die "thaw error on buffer of size: $n";
281 my $sub = shift @$args;
282 eval { $self->$sub(@$args) };
283 warn "$$ wq_worker: $@" if $@;
284 delete @$self{0..($nfd-1)};
288 sub wq_worker_loop ($) {
290 my $wqw = PublicInbox::WQWorker->new($self);
291 PublicInbox::DS->SetPostLoopCallback(sub { $wqw->{sock} });
292 PublicInbox::DS->EventLoop;
293 PublicInbox::DS->Reset;
296 sub do_sock_stream { # via wq_do, for big requests
297 my ($self, $len) = @_;
298 recv_and_run($self, delete $self->{0}, $len, 1);
301 sub wq_do { # always async
302 my ($self, $sub, $ios, @args) = @_;
303 if (my $s1 = $self->{-wq_s1}) { # run in worker
304 my $fds = [ map { fileno($_) } @$ios ];
305 my $n = $send_cmd->($s1, $fds, freeze([$sub, @args]), MSG_EOR);
306 return if defined($n);
307 croak "sendmsg error: $!" if $! != EMSGSIZE;
308 socketpair(my $r, my $w, AF_UNIX, SOCK_STREAM, 0) or
309 croak "socketpair: $!";
310 my $buf = freeze([$sub, @args]);
311 $n = $send_cmd->($s1, [ fileno($r) ],
312 freeze(['do_sock_stream', length($buf)]),
313 MSG_EOR) // croak "sendmsg: $!";
315 $n = $send_cmd->($w, $fds, $buf, 0) // croak "sendmsg: $!";
316 while ($n < length($buf)) {
317 my $x = syswrite($w, $buf, length($buf) - $n, $n) //
318 croak "syswrite: $!";
319 croak "syswrite wrote 0 bytes" if $x == 0;
323 @$self{0..$#$ios} = @$ios;
324 eval { $self->$sub(@args) };
325 warn "wq_do: $@" if $@;
326 delete @$self{0..$#$ios}; # don't close
330 sub _wq_worker_start ($$$) {
331 my ($self, $oldset, $fields) = @_;
332 my $seed = rand(0xffffffff);
333 my $pid = fork // die "fork: $!";
336 eval { PublicInbox::DS->Reset };
337 delete @$self{qw(-wq_s1 -wq_workers -wq_ppid)};
338 @$self{keys %$fields} = values(%$fields) if $fields;
339 $SIG{$_} = 'IGNORE' for (qw(PIPE));
340 $SIG{$_} = 'DEFAULT' for (qw(TTOU TTIN TERM QUIT INT CHLD));
341 local $0 = $self->{-wq_ident};
342 PublicInbox::DS::sig_setmask($oldset);
343 # ensure we properly exit even if warn() dies:
344 my $end = PublicInbox::OnDestroy->new($$, sub { exit(!!$@) });
346 my $on_destroy = $self->ipc_atfork_child;
348 wq_worker_loop($self);
350 warn "worker $self->{-wq_ident} PID:$$ died: $@" if $@;
351 undef $end; # trigger exit
353 $self->{-wq_workers}->{$pid} = \undef;
357 # starts workqueue workers if Sereal or Storable is installed
358 sub wq_workers_start {
359 my ($self, $ident, $nr_workers, $oldset, $fields) = @_;
360 ($enc && $send_cmd && $recv_cmd && defined($SEQPACKET)) or return;
361 return if $self->{-wq_s1}; # idempotent
362 $self->{-wq_s1} = $self->{-wq_s2} = undef;
363 socketpair($self->{-wq_s1}, $self->{-wq_s2}, AF_UNIX, $SEQPACKET, 0) or
364 die "socketpair: $!";
365 $self->ipc_atfork_prepare;
367 $nr_workers = $WQ_MAX_WORKERS if $nr_workers > $WQ_MAX_WORKERS;
368 my $sigset = $oldset // PublicInbox::DS::block_signals();
369 $self->{-wq_workers} = {};
370 $self->{-wq_ident} = $ident;
371 _wq_worker_start($self, $sigset, $fields) for (1..$nr_workers);
372 PublicInbox::DS::sig_setmask($sigset) unless $oldset;
373 $self->{-wq_ppid} = $$;
376 sub wq_worker_incr { # SIGTTIN handler
377 my ($self, $oldset, $fields) = @_;
378 $self->{-wq_s2} or return;
379 return if wq_workers($self) >= $WQ_MAX_WORKERS;
380 $self->ipc_atfork_prepare;
381 my $sigset = $oldset // PublicInbox::DS::block_signals();
382 _wq_worker_start($self, $sigset, $fields);
383 PublicInbox::DS::sig_setmask($sigset) unless $oldset;
386 sub wq_exit { # wakes up wq_worker_decr_wait
387 send($_[0]->{-wq_s2}, $$, MSG_EOR) // die "$$ send: $!";
391 sub wq_worker_decr { # SIGTTOU handler, kills first idle worker
393 return unless wq_workers($self);
394 my $s2 = $self->{-wq_s2} // die 'BUG: no wq_s2';
395 $self->wq_do('wq_exit', [ $s2, $s2, $s2 ]);
396 # caller must call wq_worker_decr_wait in main loop
399 sub wq_worker_decr_wait {
400 my ($self, $timeout) = @_;
401 return if $self->{-wq_ppid} != $$; # can't reap siblings or parents
402 my $s1 = $self->{-wq_s1} // croak 'BUG: no wq_s1';
403 vec(my $rin = '', fileno($s1), 1) = 1;
404 select(my $rout = $rin, undef, undef, $timeout) or
405 croak 'timed out waiting for wq_exit';
406 recv($s1, my $pid, 64, 0) // croak "recv: $!";
407 my $workers = $self->{-wq_workers} // croak 'BUG: no wq_workers';
408 delete $workers->{$pid} // croak "BUG: PID:$pid invalid";
409 dwaitpid($pid, \&ipc_worker_reap, $self);
412 # set or retrieve number of workers
414 my ($self, $nr) = @_;
415 my $cur = $self->{-wq_workers} or return;
417 while (scalar(keys(%$cur)) > $nr) {
418 $self->wq_worker_decr;
419 $self->wq_worker_decr_wait;
421 $self->wq_worker_incr while scalar(keys(%$cur)) < $nr;
427 my ($self, $nohang) = @_;
428 delete @$self{qw(-wq_s1 -wq_s2)} or return;
429 my $ppid = delete $self->{-wq_ppid} or return;
430 my $workers = delete $self->{-wq_workers} // die 'BUG: no wq_workers';
431 return if $ppid != $$; # can't reap siblings or parents
432 my @pids = map { $_ + 0 } keys %$workers;
434 push @{$self->{"-wq_old_pids.$$"}}, @pids;
436 dwaitpid($_, \&ipc_worker_reap, $self) for @pids;
442 my $pids = $self->{"-wq_old_pids.$$"} or return;
447 my ($self, $sig) = @_;
448 my $workers = $self->{-wq_workers} or return;
449 kill($sig // 'TERM', keys %$workers);
452 sub WQ_MAX_WORKERS { $WQ_MAX_WORKERS }
456 my $ppid = $self->{-wq_ppid};
457 wq_kill($self) if $ppid && $ppid == $$;
460 ipc_worker_stop($self);
463 # Sereal doesn't have dclone
464 sub deep_clone { thaw(freeze($_[-1])) }