No ext_urls

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

diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
index a6c43b22d960ae9c01765e126677f3521c44e115..0a763d0ef643ad0d5c5deb8e027b9df67d4438ae 100644 (file)
--- a/lib/PublicInbox/DS.pm
+++ b/lib/PublicInbox/DS.pm
@@ -30,13 +30,13 @@ use Time::HiRes qw(clock_gettime CLOCK_MONOTONIC);
 use Scalar::Util qw(blessed);
 use PublicInbox::Syscall qw(:epoll);
 use PublicInbox::Tmpfile;
-use Errno qw(EAGAIN EINVAL);
+use Errno qw(EAGAIN EINVAL ECHILD EINTR);
 use Carp qw(carp croak);
-our @EXPORT_OK = qw(now msg_more dwaitpid add_timer add_uniq_timer);
+our @EXPORT_OK = qw(now msg_more awaitpid add_timer add_uniq_timer);
 
 my %Stack;
 my $nextq; # queue for next_tick
-my $wait_pids; # list of [ pid, callback, callback_arg ]
+my $AWAIT_PIDS; # pid => [ $callback, @args ]
 my $reap_armed;
 my $ToClose; # sockets to close when event loop is done
 our (
@@ -74,10 +74,10 @@ sub Reset {
                # we may be iterating inside one of these on our stack
                my @q = delete @Stack{keys %Stack};
                for my $q (@q) { @$q = () }
-               $wait_pids = $nextq = $ToClose = undef;
+               $AWAIT_PIDS = $nextq = $ToClose = undef;
                $ep_io = undef; # closes real $Epoll FD
                $Epoll = undef; # may call DSKQXS::DESTROY
-       } while (@Timers || keys(%Stack) || $nextq || $wait_pids ||
+       } while (@Timers || keys(%Stack) || $nextq || $AWAIT_PIDS ||
                $ToClose || keys(%DescriptorMap) ||
                $PostLoopCallback || keys(%UniqTimer));
 
@@ -130,8 +130,7 @@ sub _InitPoller () {
                my $fd = epoll_create();
                die "epoll_create: $!" if $fd < 0;
                open($ep_io, '+<&=', $fd) or return;
-               my $fl = fcntl($ep_io, F_GETFD, 0);
-               fcntl($ep_io, F_SETFD, $fl | FD_CLOEXEC);
+               fcntl($ep_io, F_SETFD, FD_CLOEXEC);
                $fd;
        } else {
                my $cls;
@@ -202,33 +201,30 @@ sub block_signals () {
        $oldset;
 }
 
-# We can't use waitpid(-1) safely here since it can hit ``, system(),
-# and other things.  So we scan the $wait_pids list, which is hopefully
-# not too big.  We keep $wait_pids small by not calling dwaitpid()
-# until we've hit EOF when reading the stdout of the child.
+sub await_cb ($;@) {
+       my ($pid, @cb_args) = @_;
+       my $cb = shift @cb_args or return;
+       eval { $cb->($pid, @cb_args) };
+       warn "E: awaitpid($pid): $@" if $@;
+}
 
+# This relies on our Perl process is single-threaded, or at least
+# no threads are spawning and waiting on processes (``, system(), etc...)
+# Threads are officially discouraged by the Perl5 team, and I expect
+# that to remain the case.
 sub reap_pids {
        $reap_armed = undef;
-       my $tmp = $wait_pids or return;
-       $wait_pids = undef;
-       $Stack{reap_runq} = $tmp;
        my $oldset = block_signals();
-       foreach my $ary (@$tmp) {
-               my ($pid, $cb, $arg) = @$ary;
-               my $ret = waitpid($pid, WNOHANG);
-               if ($ret == 0) {
-                       push @$wait_pids, $ary; # autovivifies @$wait_pids
-               } elsif ($ret == $pid) {
-                       if ($cb) {
-                               eval { $cb->($arg, $pid) };
-                               warn "E: dwaitpid($pid) in_loop: $@" if $@;
-                       }
+       while (1) {
+               my $pid = waitpid(-1, WNOHANG) // last;
+               last if $pid <= 0;
+               if (defined(my $cb_args = delete $AWAIT_PIDS->{$pid})) {
+                       await_cb($pid, @$cb_args) if $cb_args;
                } else {
-                       warn "waitpid($pid, WNOHANG) = $ret, \$!=$!, \$?=$?";
+                       warn "W: reaped unknown PID=$pid: \$?=$?\n";
                }
        }
        sig_setmask($oldset);
-       delete $Stack{reap_runq};
 }
 
 # reentrant SIGCHLD handler (since reap_pids is not reentrant)
@@ -702,22 +698,26 @@ sub long_response ($$;@) {
        undef;
 }
 
-sub dwaitpid ($;$$) {
-       my ($pid, $cb, $arg) = @_;
-       if ($in_loop) {
-               push @$wait_pids, [ $pid, $cb, $arg ];
-               # We could've just missed our SIGCHLD, cover it, here:
-               enqueue_reap();
-       } else {
-               my $ret = waitpid($pid, 0);
+sub awaitpid {
+       my ($pid, @cb_args) = @_; # @cb_args = ($cb, @args), $cb may be undef
+       $AWAIT_PIDS->{$pid} = \@cb_args if @cb_args;
+       # provide synchronous API
+       if (defined(wantarray) || (!$in_loop && !@cb_args)) {
+               my $ret;
+again:
+               $ret = waitpid($pid, 0) // -2;
                if ($ret == $pid) {
-                       if ($cb) {
-                               eval { $cb->($arg, $pid) };
-                               carp "E: dwaitpid($pid) !in_loop: $@" if $@;
-                       }
+                       my $cb_args = delete $AWAIT_PIDS->{$pid};
+                       @cb_args = @$cb_args if !@cb_args && $cb_args;
+                       await_cb($pid, @cb_args);
                } else {
-                       carp "waitpid($pid, 0) = $ret, \$!=$!, \$?=$?";
+                       goto again if $! == EINTR;
+                       carp "waitpid($pid): $!";
+                       delete $AWAIT_PIDS->{$pid};
                }
+               return $ret;
+       } elsif ($in_loop) { # We could've just missed our SIGCHLD, cover it, here:
+               enqueue_reap();
        }
 }