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} = $$;
137 $self->{-ipc_pid} = $pid;
140 sub ipc_worker_reap { # dwaitpid callback
141 my ($self, $pid) = @_;
142 # SIGTERM (15) is our default exit signal
143 warn "PID:$pid died with \$?=$?\n" if $? && ($? & 127) != 15;
148 my $pids = delete $self->{"-wq_old_pids.$$"} or return;
149 dwaitpid($_, \&ipc_worker_reap, $self) for @$pids;
152 # for base class, override in sub classes
153 sub ipc_atfork_prepare {}
155 sub wq_atexit_child {}
157 sub ipc_atfork_child {
159 my $io = delete($self->{-ipc_atfork_child_close}) or return;
164 # idempotent, can be called regardless of whether worker is active or not
165 sub ipc_worker_stop {
167 my ($pid, $ppid) = delete(@$self{qw(-ipc_pid -ipc_ppid)});
168 my ($w_req, $r_res) = delete(@$self{qw(-ipc_req -ipc_res)});
169 if (!$w_req && !$r_res) {
170 die "unexpected PID:$pid without IPC pipes" if $pid;
173 die 'no PID with IPC pipes' unless $pid;
174 $w_req = $r_res = undef;
176 return if $$ != $ppid;
177 dwaitpid($pid, \&ipc_worker_reap, $self);
180 # use this if we have multiple readers reading curl or "pigz -dc"
181 # and writing to the same store
184 require PublicInbox::Lock;
185 $self->{-ipc_lock} //= bless { lock_path => $f }, 'PublicInbox::Lock'
188 sub ipc_async_wait ($$) {
189 my ($self, $max) = @_; # max == -1 to wait for all
190 my $aif = $self->{-async_inflight} or return;
191 my $r_res = $self->{-ipc_res} or die 'BUG: no ipc_res';
192 while (my ($sub, $bytes, $cb, $cb_arg) = splice(@$aif, 0, 4)) {
193 my $ret = _get_rec($r_res) //
194 die "no response on $sub (req.size=$bytes)";
195 $self->{-async_inflight_bytes} -= $bytes;
197 eval { $cb->($cb_arg, $ret) };
198 warn "E: $sub callback error: $@\n" if $@;
199 return if --$max == 0;
203 # call $self->$sub(@args), on a worker if ipc_worker_spawn was used
205 my ($self, $sub, @args) = @_;
206 if (my $w_req = $self->{-ipc_req}) { # run in worker
207 my $ipc_lock = $self->{-ipc_lock};
208 my $lock = $ipc_lock ? $ipc_lock->lock_for_scope : undef;
209 if (defined(wantarray)) {
210 my $r_res = $self->{-ipc_res} or die 'BUG: no ipc_res';
211 ipc_async_wait($self, -1);
212 _send_rec($w_req, [ wantarray, $sub, @args ]);
213 my $ret = _get_rec($r_res) // die "no response on $sub";
214 die $$ret if ref($ret) eq 'PublicInbox::IPC::Die';
215 wantarray ? @$ret : $$ret;
216 } else { # likely, fire-and-forget into pipe
217 _send_rec($w_req, [ undef , $sub, @args ]);
219 } else { # run locally
225 my ($self, $sub, $sub_args, $cb, $cb_arg) = @_;
226 if (my $w_req = $self->{-ipc_req}) { # run in worker
227 my $rec = _pack_rec([ 1, $sub, @$sub_args ]);
228 my $cur_bytes = \($self->{-async_inflight_bytes} //= 0);
229 while (($$cur_bytes + length($rec)) > PIPE_BUF) {
230 ipc_async_wait($self, 1);
232 my $ipc_lock = $self->{-ipc_lock};
233 my $lock = $ipc_lock ? $ipc_lock->lock_for_scope : undef;
234 print $w_req $rec or croak "print: $!";
235 $$cur_bytes += length($rec);
236 push @{$self->{-async_inflight}},
237 $sub, length($rec), $cb, $cb_arg;
239 my $ret = [ eval { $self->$sub(@$sub_args) } ];
241 $ret = ( bless(\$exc, 'PublicInbox::IPC::Die') );
243 eval { $cb->($cb_arg, $ret) };
244 warn "E: $sub callback error: $@\n" if $@;
248 # needed when there's multiple IPC workers and the parent forking
249 # causes newer siblings to inherit older siblings sockets
250 sub ipc_sibling_atfork_child {
252 my ($pid, undef) = delete(@$self{qw(-ipc_pid -ipc_ppid)});
253 delete(@$self{qw(-ipc_req -ipc_res)});
254 $pid == $$ and die "BUG: $$ ipc_atfork_child called on itself";
258 my ($self, $s2, $len, $full_stream) = @_;
259 my @fds = $recv_cmd->($s2, my $buf, $len);
260 return if scalar(@fds) && !defined($fds[0]);
261 my $n = length($buf) or return 0;
264 if (open(my $cmdfh, '+<&=', $fd)) {
265 $self->{$nfd++} = $cmdfh;
266 $cmdfh->autoflush(1);
268 die "$$ open(+<&=$fd) (FD:$nfd): $!";
271 while ($full_stream && $n < $len) {
272 my $r = sysread($s2, $buf, $len - $n, $n) // croak "read: $!";
273 croak "read EOF after $n/$len bytes" if $r == 0;
276 # Sereal dies on truncated data, Storable returns undef
277 my $args = thaw($buf) // die "thaw error on buffer of size: $n";
279 my $sub = shift @$args;
280 eval { $self->$sub(@$args) };
281 warn "$$ wq_worker: $@" if $@ && ref($@) ne 'PublicInbox::SIGPIPE';
282 delete @$self{0..($nfd-1)};
286 sub wq_worker_loop ($) {
288 my $wqw = PublicInbox::WQWorker->new($self);
289 PublicInbox::DS->SetPostLoopCallback(sub { $wqw->{sock} });
290 PublicInbox::DS->EventLoop;
291 PublicInbox::DS->Reset;
294 sub do_sock_stream { # via wq_do, for big requests
295 my ($self, $len) = @_;
296 recv_and_run($self, delete $self->{0}, $len, 1);
299 sub wq_do { # always async
300 my ($self, $sub, $ios, @args) = @_;
301 if (my $s1 = $self->{-wq_s1}) { # run in worker
302 my $fds = [ map { fileno($_) } @$ios ];
303 my $n = $send_cmd->($s1, $fds, freeze([$sub, @args]), MSG_EOR);
304 return if defined($n);
305 croak "sendmsg error: $!" if $! != EMSGSIZE;
306 socketpair(my $r, my $w, AF_UNIX, SOCK_STREAM, 0) or
307 croak "socketpair: $!";
308 my $buf = freeze([$sub, @args]);
309 $n = $send_cmd->($s1, [ fileno($r) ],
310 freeze(['do_sock_stream', length($buf)]),
311 MSG_EOR) // croak "sendmsg: $!";
313 $n = $send_cmd->($w, $fds, $buf, 0) // croak "sendmsg: $!";
314 while ($n < length($buf)) {
315 my $x = syswrite($w, $buf, length($buf) - $n, $n) //
316 croak "syswrite: $!";
317 croak "syswrite wrote 0 bytes" if $x == 0;
321 @$self{0..$#$ios} = @$ios;
322 eval { $self->$sub(@args) };
323 warn "wq_do: $@" if $@ && ref($@) ne 'PublicInbox::SIGPIPE';
324 delete @$self{0..$#$ios}; # don't close
328 sub _wq_worker_start ($$$) {
329 my ($self, $oldset, $fields) = @_;
330 my $seed = rand(0xffffffff);
331 my $pid = fork // die "fork: $!";
334 eval { PublicInbox::DS->Reset };
335 delete @$self{qw(-wq_s1 -wq_workers -wq_ppid)};
336 @$self{keys %$fields} = values(%$fields) if $fields;
337 $SIG{$_} = 'IGNORE' for (qw(PIPE));
338 $SIG{$_} = 'DEFAULT' for (qw(TTOU TTIN TERM QUIT INT CHLD));
339 local $0 = $self->{-wq_ident};
340 PublicInbox::DS::sig_setmask($oldset);
341 # ensure we properly exit even if warn() dies:
342 my $end = PublicInbox::OnDestroy->new($$, sub { exit(!!$@) });
344 my $on_destroy = $self->ipc_atfork_child;
346 wq_worker_loop($self);
348 warn "worker $self->{-wq_ident} PID:$$ died: $@" if $@;
349 undef $end; # trigger exit
351 $self->{-wq_workers}->{$pid} = \undef;
355 # starts workqueue workers if Sereal or Storable is installed
356 sub wq_workers_start {
357 my ($self, $ident, $nr_workers, $oldset, $fields) = @_;
358 ($enc && $send_cmd && $recv_cmd && defined($SEQPACKET)) or return;
359 return if $self->{-wq_s1}; # idempotent
360 $self->{-wq_s1} = $self->{-wq_s2} = undef;
361 socketpair($self->{-wq_s1}, $self->{-wq_s2}, AF_UNIX, $SEQPACKET, 0) or
362 die "socketpair: $!";
363 $self->ipc_atfork_prepare;
365 $nr_workers = $WQ_MAX_WORKERS if $nr_workers > $WQ_MAX_WORKERS;
366 my $sigset = $oldset // PublicInbox::DS::block_signals();
367 $self->{-wq_workers} = {};
368 $self->{-wq_ident} = $ident;
369 _wq_worker_start($self, $sigset, $fields) for (1..$nr_workers);
370 PublicInbox::DS::sig_setmask($sigset) unless $oldset;
371 $self->{-wq_ppid} = $$;
374 sub wq_worker_incr { # SIGTTIN handler
375 my ($self, $oldset, $fields) = @_;
376 $self->{-wq_s2} or return;
377 return if wq_workers($self) >= $WQ_MAX_WORKERS;
378 $self->ipc_atfork_prepare;
379 my $sigset = $oldset // PublicInbox::DS::block_signals();
380 _wq_worker_start($self, $sigset, $fields);
381 PublicInbox::DS::sig_setmask($sigset) unless $oldset;
384 sub wq_exit { # wakes up wq_worker_decr_wait
385 send($_[0]->{-wq_s2}, $$, MSG_EOR) // die "$$ send: $!";
389 sub wq_worker_decr { # SIGTTOU handler, kills first idle worker
391 return unless wq_workers($self);
392 my $s2 = $self->{-wq_s2} // die 'BUG: no wq_s2';
393 $self->wq_do('wq_exit', [ $s2, $s2, $s2 ]);
394 # caller must call wq_worker_decr_wait in main loop
397 sub wq_worker_decr_wait {
398 my ($self, $timeout) = @_;
399 return if $self->{-wq_ppid} != $$; # can't reap siblings or parents
400 my $s1 = $self->{-wq_s1} // croak 'BUG: no wq_s1';
401 vec(my $rin = '', fileno($s1), 1) = 1;
402 select(my $rout = $rin, undef, undef, $timeout) or
403 croak 'timed out waiting for wq_exit';
404 recv($s1, my $pid, 64, 0) // croak "recv: $!";
405 my $workers = $self->{-wq_workers} // croak 'BUG: no wq_workers';
406 delete $workers->{$pid} // croak "BUG: PID:$pid invalid";
407 dwaitpid($pid, \&ipc_worker_reap, $self);
410 # set or retrieve number of workers
412 my ($self, $nr) = @_;
413 my $cur = $self->{-wq_workers} or return;
415 while (scalar(keys(%$cur)) > $nr) {
416 $self->wq_worker_decr;
417 $self->wq_worker_decr_wait;
419 $self->wq_worker_incr while scalar(keys(%$cur)) < $nr;
425 my ($self, $nohang) = @_;
426 delete @$self{qw(-wq_s1 -wq_s2)} or return;
427 my $ppid = delete $self->{-wq_ppid} or return;
428 my $workers = delete $self->{-wq_workers} // die 'BUG: no wq_workers';
429 return if $ppid != $$; # can't reap siblings or parents
430 my @pids = map { $_ + 0 } keys %$workers;
432 push @{$self->{"-wq_old_pids.$$"}}, @pids;
434 dwaitpid($_, \&ipc_worker_reap, $self) for @pids;
440 my $pids = $self->{"-wq_old_pids.$$"} or return;
445 my ($self, $sig) = @_;
446 my $workers = $self->{-wq_workers} or return;
447 kill($sig // 'TERM', keys %$workers);
450 sub WQ_MAX_WORKERS { $WQ_MAX_WORKERS }
454 my $ppid = $self->{-wq_ppid};
455 wq_kill($self) if $ppid && $ppid == $$;
458 ipc_worker_stop($self);
461 # Sereal doesn't have dclone
462 sub deep_clone { thaw(freeze($_[-1])) }