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 Socket qw(AF_UNIX MSG_EOR SOCK_STREAM);
18 use Errno qw(EMSGSIZE);
19 my $SEQPACKET = eval { Socket::SOCK_SEQPACKET() }; # portable enough?
20 use constant PIPE_BUF => $^O eq 'linux' ? 4096 : POSIX::_POSIX_PIPE_BUF();
21 my $WQ_MAX_WORKERS = 4096;
23 # ->imports at BEGIN turns sereal_*_with_object into custom ops on 5.14+
24 # and eliminate method call overhead
27 require Sereal::Encoder;
28 require Sereal::Decoder;
29 Sereal::Encoder->import('sereal_encode_with_object');
30 Sereal::Decoder->import('sereal_decode_with_object');
31 ($enc, $dec) = (Sereal::Encoder->new, Sereal::Decoder->new);
35 if ($enc && $dec) { # should be custom ops
36 *freeze = sub ($) { sereal_encode_with_object $enc, $_[0] };
37 *thaw = sub ($) { sereal_decode_with_object $dec, $_[0], my $ret };
39 eval { # some distros have Storable as a separate package from Perl
41 Storable->import(qw(freeze thaw));
43 } // warn("Storable (part of Perl) missing: $@\n");
46 my $recv_cmd = PublicInbox::Spawn->can('recv_cmd4');
47 my $send_cmd = PublicInbox::Spawn->can('send_cmd4') // do {
48 require PublicInbox::CmdIPC4;
49 $recv_cmd //= PublicInbox::CmdIPC4->can('recv_cmd4');
50 PublicInbox::CmdIPC4->can('send_cmd4');
55 defined(my $len = <$r>) or return;
56 chop($len) eq "\n" or croak "no LF byte in $len";
57 defined(my $n = read($r, my $buf, $len)) or croak "read error: $!";
58 $n == $len or croak "short read: $n != $len";
64 my $buf = freeze($ref);
65 length($buf) . "\n" . $buf;
70 print $w _pack_rec($ref) or croak "print: $!";
73 sub ipc_return ($$$) {
74 my ($w, $ret, $exc) = @_;
75 _send_rec($w, $exc ? bless(\$exc, 'PublicInbox::IPC::Die') : $ret);
78 sub ipc_worker_loop ($$$) {
79 my ($self, $r_req, $w_res) = @_;
80 my ($rec, $wantarray, $sub, @args);
82 while ($rec = _get_rec($r_req)) {
83 ($wantarray, $sub, @args) = @$rec;
84 # no waiting if client doesn't care,
85 # this is the overwhelmingly likely case
86 if (!defined($wantarray)) {
87 eval { $self->$sub(@args) };
88 warn "$$ die: $@ (from nowait $sub)\n" if $@;
89 } elsif ($wantarray) {
90 my @ret = eval { $self->$sub(@args) };
91 ipc_return($w_res, \@ret, $@);
92 } else { # '' => wantscalar
93 my $ret = eval { $self->$sub(@args) };
94 ipc_return($w_res, \$ret, $@);
99 # starts a worker if Sereal or Storable is installed
100 sub ipc_worker_spawn {
101 my ($self, $ident, $oldset) = @_;
102 return unless $enc; # no Sereal or Storable
103 return if ($self->{-ipc_ppid} // -1) == $$; # idempotent
104 delete(@$self{qw(-ipc_req -ipc_res -ipc_ppid -ipc_pid)});
105 pipe(my ($r_req, $w_req)) or die "pipe: $!";
106 pipe(my ($r_res, $w_res)) or die "pipe: $!";
107 my $sigset = $oldset // PublicInbox::DS::block_signals();
108 $self->ipc_atfork_prepare;
109 my $seed = rand(0xffffffff);
110 my $pid = fork // die "fork: $!";
113 eval { PublicInbox::DS->Reset };
114 delete @$self{qw(-wq_s1 -wq_s2 -wq_workers -wq_ppid)};
115 $w_req = $r_res = undef;
116 $w_res->autoflush(1);
117 $SIG{$_} = 'IGNORE' for (qw(TERM INT QUIT));
119 PublicInbox::DS::sig_setmask($sigset);
120 # ensure we properly exit even if warn() dies:
121 my $end = PublicInbox::OnDestroy->new($$, sub { exit(!!$@) });
123 my $on_destroy = $self->ipc_atfork_child;
125 ipc_worker_loop($self, $r_req, $w_res);
127 die "worker $ident PID:$$ died: $@\n" if $@;
128 undef $end; # trigger exit
130 PublicInbox::DS::sig_setmask($sigset) unless $oldset;
131 $r_req = $w_res = undef;
132 $w_req->autoflush(1);
133 $self->{-ipc_req} = $w_req;
134 $self->{-ipc_res} = $r_res;
135 $self->{-ipc_ppid} = $$;
136 $self->{-ipc_pid} = $pid;
139 sub ipc_worker_reap { # dwaitpid callback
140 my ($self, $pid) = @_;
141 # SIGTERM (15) is our default exit signal
142 warn "PID:$pid died with \$?=$?\n" if $? && ($? & 127) != 15;
147 my $pids = delete $self->{"-wq_old_pids.$$"} or return;
148 dwaitpid($_, \&ipc_worker_reap, $self) for @$pids;
151 # for base class, override in sub classes
152 sub ipc_atfork_prepare {}
154 sub ipc_atfork_child {
156 my $io = delete($self->{-ipc_atfork_child_close}) or return;
161 # idempotent, can be called regardless of whether worker is active or not
162 sub ipc_worker_stop {
164 my ($pid, $ppid) = delete(@$self{qw(-ipc_pid -ipc_ppid)});
165 my ($w_req, $r_res) = delete(@$self{qw(-ipc_req -ipc_res)});
166 if (!$w_req && !$r_res) {
167 die "unexpected PID:$pid without IPC pipes" if $pid;
170 die 'no PID with IPC pipes' unless $pid;
171 $w_req = $r_res = undef;
173 return if $$ != $ppid;
174 dwaitpid($pid, \&ipc_worker_reap, $self);
177 # use this if we have multiple readers reading curl or "pigz -dc"
178 # and writing to the same store
181 require PublicInbox::Lock;
182 $self->{-ipc_lock} //= bless { lock_path => $f }, 'PublicInbox::Lock'
185 sub ipc_async_wait ($$) {
186 my ($self, $max) = @_; # max == -1 to wait for all
187 my $aif = $self->{-async_inflight} or return;
188 my $r_res = $self->{-ipc_res} or die 'BUG: no ipc_res';
189 while (my ($sub, $bytes, $cb, $cb_arg) = splice(@$aif, 0, 4)) {
190 my $ret = _get_rec($r_res) //
191 die "no response on $sub (req.size=$bytes)";
192 $self->{-async_inflight_bytes} -= $bytes;
194 eval { $cb->($cb_arg, $ret) };
195 warn "E: $sub callback error: $@\n" if $@;
196 return if --$max == 0;
200 # call $self->$sub(@args), on a worker if ipc_worker_spawn was used
202 my ($self, $sub, @args) = @_;
203 if (my $w_req = $self->{-ipc_req}) { # run in worker
204 my $ipc_lock = $self->{-ipc_lock};
205 my $lock = $ipc_lock ? $ipc_lock->lock_for_scope : undef;
206 if (defined(wantarray)) {
207 my $r_res = $self->{-ipc_res} or die 'BUG: no ipc_res';
208 ipc_async_wait($self, -1);
209 _send_rec($w_req, [ wantarray, $sub, @args ]);
210 my $ret = _get_rec($r_res) // die "no response on $sub";
211 die $$ret if ref($ret) eq 'PublicInbox::IPC::Die';
212 wantarray ? @$ret : $$ret;
213 } else { # likely, fire-and-forget into pipe
214 _send_rec($w_req, [ undef , $sub, @args ]);
216 } else { # run locally
222 my ($self, $sub, $sub_args, $cb, $cb_arg) = @_;
223 if (my $w_req = $self->{-ipc_req}) { # run in worker
224 my $rec = _pack_rec([ 1, $sub, @$sub_args ]);
225 my $cur_bytes = \($self->{-async_inflight_bytes} //= 0);
226 while (($$cur_bytes + length($rec)) > PIPE_BUF) {
227 ipc_async_wait($self, 1);
229 my $ipc_lock = $self->{-ipc_lock};
230 my $lock = $ipc_lock ? $ipc_lock->lock_for_scope : undef;
231 print $w_req $rec or croak "print: $!";
232 $$cur_bytes += length($rec);
233 push @{$self->{-async_inflight}},
234 $sub, length($rec), $cb, $cb_arg;
236 my $ret = [ eval { $self->$sub(@$sub_args) } ];
238 $ret = ( bless(\$exc, 'PublicInbox::IPC::Die') );
240 eval { $cb->($cb_arg, $ret) };
241 warn "E: $sub callback error: $@\n" if $@;
245 # needed when there's multiple IPC workers and the parent forking
246 # causes newer siblings to inherit older siblings sockets
247 sub ipc_sibling_atfork_child {
249 my ($pid, undef) = delete(@$self{qw(-ipc_pid -ipc_ppid)});
250 delete(@$self{qw(-ipc_req -ipc_res)});
251 $pid == $$ and die "BUG: $$ ipc_atfork_child called on itself";
255 my ($self, $s2, $len, $full_stream) = @_;
256 my @fds = $recv_cmd->($s2, my $buf, $len);
257 my $n = length($buf // '') or return;
260 if (open(my $cmdfh, '+<&=', $fd)) {
261 $self->{$nfd++} = $cmdfh;
262 $cmdfh->autoflush(1);
264 die "$$ open(+<&=$fd) (FD:$nfd): $!";
267 while ($full_stream && $n < $len) {
268 my $r = sysread($s2, $buf, $len - $n, $n) // croak "read: $!";
269 croak "read EOF after $n/$len bytes" if $r == 0;
272 # Sereal dies on truncated data, Storable returns undef
273 my $args = thaw($buf) // die "thaw error on buffer of size: $n";
275 my $sub = shift @$args;
276 eval { $self->$sub(@$args) };
277 warn "$$ wq_worker: $@" if $@ && ref($@) ne 'PublicInbox::SIGPIPE';
278 delete @$self{0..($nfd-1)};
282 sub wq_worker_loop ($) {
284 my $len = $self->{wq_req_len} // (4096 * 33);
285 my $s2 = $self->{-wq_s2} // die 'BUG: no -wq_s2';
286 1 while (_recv_and_run($self, $s2, $len));
289 sub do_sock_stream { # via wq_do, for big requests
290 my ($self, $len) = @_;
291 _recv_and_run($self, delete $self->{0}, $len, 1);
294 sub wq_do { # always async
295 my ($self, $sub, $ios, @args) = @_;
296 if (my $s1 = $self->{-wq_s1}) { # run in worker
297 my $fds = [ map { fileno($_) } @$ios ];
298 my $n = $send_cmd->($s1, $fds, freeze([$sub, @args]), MSG_EOR);
299 return if defined($n);
300 croak "sendmsg error: $!" if $! != EMSGSIZE;
301 socketpair(my $r, my $w, AF_UNIX, SOCK_STREAM, 0) or
302 croak "socketpair: $!";
303 my $buf = freeze([$sub, @args]);
304 $n = $send_cmd->($s1, [ fileno($r) ],
305 freeze(['do_sock_stream', length($buf)]),
306 MSG_EOR) // croak "sendmsg: $!";
308 $n = $send_cmd->($w, $fds, $buf, 0) // croak "sendmsg: $!";
309 while ($n < length($buf)) {
310 my $x = syswrite($w, $buf, length($buf) - $n, $n) //
311 croak "syswrite: $!";
312 croak "syswrite wrote 0 bytes" if $x == 0;
316 @$self{0..$#$ios} = @$ios;
317 eval { $self->$sub(@args) };
318 warn "wq_do: $@" if $@ && ref($@) ne 'PublicInbox::SIGPIPE';
319 delete @$self{0..$#$ios}; # don't close
323 sub _wq_worker_start ($$$) {
324 my ($self, $oldset, $fields) = @_;
325 my $seed = rand(0xffffffff);
326 my $pid = fork // die "fork: $!";
329 eval { PublicInbox::DS->Reset };
330 delete @$self{qw(-wq_s1 -wq_workers -wq_ppid)};
331 @$self{keys %$fields} = values(%$fields) if $fields;
332 $SIG{$_} = 'IGNORE' for (qw(PIPE));
333 $SIG{$_} = 'DEFAULT' for (qw(TTOU TTIN TERM QUIT INT CHLD));
334 local $0 = $self->{-wq_ident};
335 PublicInbox::DS::sig_setmask($oldset);
336 # ensure we properly exit even if warn() dies:
337 my $end = PublicInbox::OnDestroy->new($$, sub { exit(!!$@) });
339 my $on_destroy = $self->ipc_atfork_child;
341 wq_worker_loop($self);
343 warn "worker $self->{-wq_ident} PID:$$ died: $@" if $@;
344 undef $end; # trigger exit
346 $self->{-wq_workers}->{$pid} = \undef;
350 # starts workqueue workers if Sereal or Storable is installed
351 sub wq_workers_start {
352 my ($self, $ident, $nr_workers, $oldset, $fields) = @_;
353 ($enc && $send_cmd && $recv_cmd && defined($SEQPACKET)) or return;
354 return if $self->{-wq_s1}; # idempotent
355 $self->{-wq_s1} = $self->{-wq_s2} = undef;
356 socketpair($self->{-wq_s1}, $self->{-wq_s2}, AF_UNIX, $SEQPACKET, 0) or
357 die "socketpair: $!";
358 $self->ipc_atfork_prepare;
360 $nr_workers = $WQ_MAX_WORKERS if $nr_workers > $WQ_MAX_WORKERS;
361 my $sigset = $oldset // PublicInbox::DS::block_signals();
362 $self->{-wq_workers} = {};
363 $self->{-wq_ident} = $ident;
364 _wq_worker_start($self, $sigset, $fields) for (1..$nr_workers);
365 PublicInbox::DS::sig_setmask($sigset) unless $oldset;
366 $self->{-wq_ppid} = $$;
369 sub wq_worker_incr { # SIGTTIN handler
370 my ($self, $oldset, $fields) = @_;
371 $self->{-wq_s2} or return;
372 return if wq_workers($self) >= $WQ_MAX_WORKERS;
373 $self->ipc_atfork_prepare;
374 my $sigset = $oldset // PublicInbox::DS::block_signals();
375 _wq_worker_start($self, $sigset, $fields);
376 PublicInbox::DS::sig_setmask($sigset) unless $oldset;
379 sub wq_exit { # wakes up wq_worker_decr_wait
380 send($_[0]->{-wq_s2}, $$, MSG_EOR) // die "$$ send: $!";
384 sub wq_worker_decr { # SIGTTOU handler, kills first idle worker
386 return unless wq_workers($self);
387 my $s2 = $self->{-wq_s2} // die 'BUG: no wq_s2';
388 $self->wq_do('wq_exit', [ $s2, $s2, $s2 ]);
389 # caller must call wq_worker_decr_wait in main loop
392 sub wq_worker_decr_wait {
393 my ($self, $timeout) = @_;
394 return if $self->{-wq_ppid} != $$; # can't reap siblings or parents
395 my $s1 = $self->{-wq_s1} // croak 'BUG: no wq_s1';
396 vec(my $rin = '', fileno($s1), 1) = 1;
397 select(my $rout = $rin, undef, undef, $timeout) or
398 croak 'timed out waiting for wq_exit';
399 recv($s1, my $pid, 64, 0) // croak "recv: $!";
400 my $workers = $self->{-wq_workers} // croak 'BUG: no wq_workers';
401 delete $workers->{$pid} // croak "BUG: PID:$pid invalid";
402 dwaitpid($pid, \&ipc_worker_reap, $self);
405 # set or retrieve number of workers
407 my ($self, $nr) = @_;
408 my $cur = $self->{-wq_workers} or return;
410 while (scalar(keys(%$cur)) > $nr) {
411 $self->wq_worker_decr;
412 $self->wq_worker_decr_wait;
414 $self->wq_worker_incr while scalar(keys(%$cur)) < $nr;
420 my ($self, $nohang) = @_;
421 delete @$self{qw(-wq_s1 -wq_s2)} or return;
422 my $ppid = delete $self->{-wq_ppid} or return;
423 my $workers = delete $self->{-wq_workers} // die 'BUG: no wq_workers';
424 return if $ppid != $$; # can't reap siblings or parents
425 my @pids = map { $_ + 0 } keys %$workers;
427 push @{$self->{"-wq_old_pids.$$"}}, @pids;
429 dwaitpid($_, \&ipc_worker_reap, $self) for @pids;
435 my $pids = $self->{"-wq_old_pids.$$"} or return;
440 my ($self, $sig) = @_;
441 my $workers = $self->{-wq_workers} or return;
442 kill($sig // 'TERM', keys %$workers);
445 sub WQ_MAX_WORKERS { $WQ_MAX_WORKERS }
449 my $ppid = $self->{-wq_ppid};
450 wq_kill($self) if $ppid && $ppid == $$;
453 ipc_worker_stop($self);
456 # Sereal doesn't have dclone
457 sub deep_clone { thaw(freeze($_[-1])) }