lei: fork + FD cleanup

[public-inbox.git] / lib / PublicInbox / IPC.pm

diff --git a/lib/PublicInbox/IPC.pm b/lib/PublicInbox/IPC.pm
index 4db4b8ea26e3b87dd9ce408ee21620883186b4de..88f81e477ec07d58c97f80f8ccb091d88f7f6d2d 100644 (file)
--- a/lib/PublicInbox/IPC.pm
+++ b/lib/PublicInbox/IPC.pm
@@ -126,7 +126,7 @@ sub ipc_worker_spawn {
        pipe(my ($r_res, $w_res)) or die "pipe: $!";
        my $sigset = $oldset // PublicInbox::DS::block_signals();
        my $parent = $$;
-       $self->ipc_atfork_parent;
+       $self->ipc_atfork_prepare;
        defined(my $pid = fork) or die "fork: $!";
        if ($pid == 0) {
                eval { PublicInbox::DS->Reset };
@@ -155,8 +155,14 @@ sub ipc_worker_reap { # dwaitpid callback
 }
 
 # for base class, override in sub classes
-sub ipc_atfork_parent {}
-sub ipc_atfork_child {}
+sub ipc_atfork_prepare {}
+
+sub ipc_atfork_child {
+       my ($self) = @_;
+       my $io = delete($self->{-ipc_atfork_child_close}) or return;
+       close($_) for @$io;
+       undef;
+}
 
 # idempotent, can be called regardless of whether worker is active or not
 sub ipc_worker_stop {
@@ -251,14 +257,21 @@ sub ipc_sibling_atfork_child {
        $pid == $$ and die "BUG: $$ ipc_atfork_child called on itself";
 }
 
+sub _close_recvd ($) {
+       my ($self) = @_;
+       close($_) for (grep { defined } (delete @$self{0..2}));
+}
+
 sub wq_worker_loop ($) {
        my ($self) = @_;
        my $buf;
        my $len = $self->{wq_req_len} // (4096 * 33);
-       my ($rec, $sub, @args);
+       my ($sub, $args);
        my $s2 = $self->{-wq_s2} // die 'BUG: no -wq_s2';
        local $SIG{PIPE} = sub {
-               die(bless(\"$_[0]", __PACKAGE__.'::PIPE')) if $sub;
+               my $cur_sub = $sub;
+               _close_recvd($self);
+               die(bless(\$cur_sub, __PACKAGE__.'::PIPE')) if $cur_sub;
        };
        my $rcv = $self->{-wq_recv_cmd} // $recv_cmd;
        while (1) {
@@ -267,22 +280,25 @@ sub wq_worker_loop ($) {
                my @m = @{$self->{wq_open_modes} // [qw( +<&= >&= >&= )]};
                for my $fd (@fds) {
                        my $mode = shift(@m);
-                       if (open(my $fh, $mode, $fd)) {
-                               $self->{$i++} = $fh;
-                               $fh->autoflush(1);
+                       if (open(my $cmdfh, $mode, $fd)) {
+                               $self->{$i++} = $cmdfh;
+                               $cmdfh->autoflush(1);
                        } else {
                                die "$$ open($mode$fd) (FD:$i): $!";
                        }
                }
-               # Sereal dies, Storable returns undef
-               $rec = thaw($buf) //
+               # Sereal dies on truncated data, Storable returns undef
+               $args = thaw($buf) //
                        die "thaw error on buffer of size:".length($buf);
-               ($sub, @args) = @$rec;
-               eval { $self->$sub(@args) };
+               eval {
+                       $sub = shift @$args;
+                       eval { $self->$sub(@$args) };
+                       undef $sub; # quiet SIG{PIPE} handler
+                       die $@ if $@;
+               };
                warn "$$ wq_worker: $@" if $@ && ref $@ ne __PACKAGE__.'::PIPE';
-               undef $sub; # quiet SIG{PIPE} handler
                # need to close explicitly to avoid warnings after SIGPIPE
-               close($_) for (delete(@$self{0..2}));
+               _close_recvd($self);
        }
 }
 
@@ -306,14 +322,17 @@ sub _wq_worker_start ($$) {
                eval { PublicInbox::DS->Reset };
                close(delete $self->{-wq_s1});
                delete $self->{qw(-wq_workers -wq_ppid)};
-               $SIG{$_} = 'IGNORE' for (qw(TTOU TTIN));
-               $SIG{$_} = 'DEFAULT' for (qw(TERM QUIT INT));
+               $SIG{$_} = 'IGNORE' for (qw(PIPE TTOU TTIN));
+               $SIG{$_} = 'DEFAULT' for (qw(TERM QUIT INT CHLD));
                local $0 = $self->{-wq_ident};
                PublicInbox::DS::sig_setmask($oldset);
+               # ensure we properly exit even if warn() dies:
+               my $end = PublicInbox::OnDestroy->new($$, sub { exit(!!$@) });
                my $on_destroy = $self->ipc_atfork_child;
                eval { wq_worker_loop($self) };
                warn "worker $self->{-wq_ident} PID:$$ died: $@" if $@;
-               exit($@ ? 1 : 0);
+               undef $on_destroy;
+               undef $end; # trigger exit
        } else {
                $self->{-wq_workers}->{$pid} = \undef;
        }
@@ -326,7 +345,7 @@ sub wq_workers_start {
        return if $self->{-wq_s1}; # idempotent
        my ($s1, $s2);
        socketpair($s1, $s2, AF_UNIX, $SEQPACKET, 0) or die "socketpair: $!";
-       $self->ipc_atfork_parent;
+       $self->ipc_atfork_prepare;
        $nr_workers //= 4;
        $nr_workers = $WQ_MAX_WORKERS if $nr_workers > $WQ_MAX_WORKERS;
        my $sigset = $oldset // PublicInbox::DS::block_signals();
@@ -343,7 +362,7 @@ sub wq_worker_incr { # SIGTTIN handler
        my ($self, $oldset) = @_;
        $self->{-wq_s2} or return;
        return if wq_workers($self) >= $WQ_MAX_WORKERS;
-       $self->ipc_atfork_parent;
+       $self->ipc_atfork_prepare;
        my $sigset = $oldset // PublicInbox::DS::block_signals();
        _wq_worker_start($self, $sigset);
        PublicInbox::DS::sig_setmask($sigset) unless $oldset;