-# Copyright (C) 2020 all contributors <meta@public-inbox.org>
+# Copyright (C) 2020-2021 all contributors <meta@public-inbox.org>
# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
# base class for remote IPC calls, requires Storable
package PublicInbox::IPC;
use strict;
use v5.10.1;
-use Socket qw(AF_UNIX SOCK_STREAM);
use Carp qw(confess croak);
use PublicInbox::Sigfd;
my ($enc, $dec);
-# ->imports at BEGIN turns serial_*_with_object into custom ops on 5.14+
+# ->imports at BEGIN turns sereal_*_with_object into custom ops on 5.14+
# and eliminate method call overhead
BEGIN {
eval {
}
sub _get_rec ($) {
- my ($sock) = @_;
- local $/ = "\n";
- defined(my $len = <$sock>) or return;
+ my ($r) = @_;
+ defined(my $len = <$r>) or return;
chop($len) eq "\n" or croak "no LF byte in $len";
- defined(my $r = read($sock, my $buf, $len)) or croak "read error: $!";
- $r == $len or croak "short read: $r != $len";
+ defined(my $n = read($r, my $buf, $len)) or croak "read error: $!";
+ $n == $len or croak "short read: $n != $len";
thaw($buf);
}
sub _send_rec ($$) {
- my ($sock, $ref) = @_;
+ my ($w, $ref) = @_;
my $buf = freeze($ref);
- print $sock length($buf), "\n", $buf or croak "print: $!";
+ print $w length($buf), "\n", $buf or croak "print: $!";
}
sub ipc_return ($$$) {
- my ($s2, $ret, $exc) = @_;
- _send_rec($s2, $exc ? bless(\$exc, 'PublicInbox::IPC::Die') : $ret);
+ my ($w, $ret, $exc) = @_;
+ _send_rec($w, $exc ? bless(\$exc, 'PublicInbox::IPC::Die') : $ret);
}
-sub ipc_worker_loop ($$) {
- my ($self, $s2) = @_;
- while (my $rec = _get_rec($s2)) {
- my ($wantarray, $sub, @args) = @$rec;
- if (!defined($wantarray)) { # no waiting if client doesn't care
+sub ipc_worker_loop ($$$) {
+ my ($self, $r_req, $w_res) = @_;
+ my ($rec, $wantarray, $sub, @args);
+ local $/ = "\n";
+ while ($rec = _get_rec($r_req)) {
+ ($wantarray, $sub, @args) = @$rec;
+ # no waiting if client doesn't care,
+ # this is the overwhelmingly likely case
+ if (!defined($wantarray)) {
eval { $self->$sub(@args) };
- eval { warn "die: $@ (from nowait $sub)\n" } if $@;
+ eval { warn "$$ die: $@ (from nowait $sub)\n" } if $@;
} elsif ($wantarray) {
my @ret = eval { $self->$sub(@args) };
- ipc_return($s2, \@ret, $@);
- } else {
+ ipc_return($w_res, \@ret, $@);
+ } else { # '' => wantscalar
my $ret = eval { $self->$sub(@args) };
- ipc_return($s2, \$ret, $@);
+ ipc_return($w_res, \$ret, $@);
}
}
}
+# starts a worker if Sereal or Storable is installed
sub ipc_worker_spawn {
my ($self, $ident, $oldset) = @_;
- return unless $enc;
- my $pid = $self->{-ipc_worker_pid};
- confess "BUG: already spawned PID:$pid" if $pid;
- confess "BUG: already have worker socket" if $self->{-ipc_sock};
- my ($s1, $s2);
- socketpair($s1, $s2, AF_UNIX, SOCK_STREAM, 0) or die "socketpair: $!";
- my $sigset = $oldset // PublicInbox::Sigfd::block_signals();
+ return unless $enc; # no Sereal or Storable
+ return if ($self->{-ipc_ppid} // -1) == $$; # idempotent
+ delete(@$self{qw(-ipc_req -ipc_res -ipc_ppid -ipc_pid)});
+ pipe(my ($r_req, $w_req)) or die "pipe: $!";
+ pipe(my ($r_res, $w_res)) or die "pipe: $!";
+ my $sigset = $oldset // PublicInbox::DS::block_signals();
my $parent = $$;
$self->ipc_atfork_parent;
- defined($pid = fork) or die "fork: $!";
+ defined(my $pid = fork) or die "fork: $!";
if ($pid == 0) {
eval { PublicInbox::DS->Reset };
$self->{-ipc_parent_pid} = $parent;
- close $s1 or die "close(\$s1): $!";
- $s2->autoflush(1);
+ $w_req = $r_res = undef;
+ $w_res->autoflush(1);
$SIG{$_} = 'IGNORE' for (qw(TERM INT QUIT));
local $0 = $ident;
- PublicInbox::Sigfd::sig_setmask($oldset);
- $self->ipc_atfork_child;
- eval { ipc_worker_loop($self, $s2) };
+ PublicInbox::DS::sig_setmask($oldset);
+ my $on_destroy = $self->ipc_atfork_child;
+ eval { ipc_worker_loop($self, $r_req, $w_res) };
die "worker $ident PID:$$ died: $@\n" if $@;
exit;
}
- PublicInbox::Sigfd::sig_setmask($sigset) unless $oldset;
- close $s2 or die "close(\$s2): $!";
- $s1->autoflush(1);
- $self->{-ipc_sock} = $s1;
- $self->{-ipc_worker_pid} = $pid;
+ PublicInbox::DS::sig_setmask($sigset) unless $oldset;
+ $r_req = $w_res = undef;
+ $w_req->autoflush(1);
+ $self->{-ipc_req} = $w_req;
+ $self->{-ipc_res} = $r_res;
+ $self->{-ipc_ppid} = $$;
+ $self->{-ipc_pid} = $pid;
}
sub ipc_worker_reap { # dwaitpid callback
warn "PID:$pid died with \$?=$?\n" if $?;
}
-# for base class, override in superclasses
+# for base class, override in sub classes
sub ipc_atfork_parent {}
sub ipc_atfork_child {}
+# should only be called inside the worker process
sub ipc_worker_exit {
my (undef, $code) = @_;
exit($code);
}
+# idempotent, can be called regardless of whether worker is active or not
sub ipc_worker_stop {
my ($self) = @_;
- my $pid;
- my $s1 = delete $self->{-ipc_sock} or do {
- $pid = delete $self->{-ipc_worker_pid} and
- die "unexpected PID:$pid without ipc_sock";
- return;
- };
- $pid = delete $self->{-ipc_worker_pid} or die "no PID?";
- _send_rec($s1, [ undef, 'ipc_worker_exit', 0 ]);
- shutdown($s1, 2) or die "shutdown(\$s1) for PID:$pid";
+ my ($pid, $ppid) = delete(@$self{qw(-ipc_pid -ipc_ppid)});
+ my ($w_req, $r_res) = delete(@$self{qw(-ipc_req -ipc_res)});
+ if (!$w_req && !$r_res) {
+ die "unexpected PID:$pid without IPC pipes" if $pid;
+ return; # idempotent
+ }
+ die 'no PID with IPC pipes' unless $pid;
+ _send_rec($w_req, [ undef, 'ipc_worker_exit', 0 ]);
+ $w_req = $r_res = undef;
+
+ # allow any sibling to send ipc_worker_exit, but siblings can't wait
+ return if $$ != $ppid;
eval {
my $reap = $self->can('ipc_worker_reap');
PublicInbox::DS::dwaitpid($pid, $reap, $self);
$self->{-ipc_lock} //= bless { lock_path => $f }, 'PublicInbox::Lock'
}
+# call $self->$sub(@args), on a worker if ipc_worker_spawn was used
sub ipc_do {
my ($self, $sub, @args) = @_;
- if (my $s1 = $self->{-ipc_sock}) {
+ if (my $w_req = $self->{-ipc_req}) { # run in worker
my $ipc_lock = $self->{-ipc_lock};
my $lock = $ipc_lock ? $ipc_lock->lock_for_scope : undef;
- _send_rec($s1, [ wantarray, $sub, @args ]);
- return unless defined(wantarray);
- my $ret = _get_rec($s1) // die "no response on $sub";
- die $$ret if ref($ret) eq 'PublicInbox::IPC::Die';
- wantarray ? @$ret : $$ret;
- } else {
+ if (defined(wantarray)) {
+ my $r_res = $self->{-ipc_res} or die 'no ipc_res';
+ _send_rec($w_req, [ wantarray, $sub, @args ]);
+ my $ret = _get_rec($r_res) // die "no response on $sub";
+ die $$ret if ref($ret) eq 'PublicInbox::IPC::Die';
+ wantarray ? @$ret : $$ret;
+ } else { # likely, fire-and-forget into pipe
+ _send_rec($w_req, [ undef , $sub, @args ]);
+ }
+ } else { # run locally
$self->$sub(@args);
}
}
+# needed when there's multiple IPC workers and the parent forking
+# causes newer siblings to inherit older siblings sockets
+sub ipc_sibling_atfork_child {
+ my ($self) = @_;
+ my ($pid, undef) = delete(@$self{qw(-ipc_pid -ipc_ppid)});
+ delete(@$self{qw(-ipc_req -ipc_res)});
+ $pid == $$ and die "BUG: $$ ipc_atfork_child called on itself";
+}
+
1;