X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=lib%2FPublicInbox%2FQspawn.pm;h=63ec3648c933bdb7775a51a2fe90e3cfc235231c;hb=95bdac7f09c69036efed537a4d03d5bdd2ae4eb6;hp=f2630a0f0109a624690edf38b849423b9b0af8dd;hpb=84d8920b92686e975929aebe845b6d4ea0a9ef0d;p=public-inbox.git

diff --git a/lib/PublicInbox/Qspawn.pm b/lib/PublicInbox/Qspawn.pm
index f2630a0f..63ec3648 100644
--- a/lib/PublicInbox/Qspawn.pm
+++ b/lib/PublicInbox/Qspawn.pm
@@ -1,4 +1,4 @@
-# Copyright (C) 2016-2019 all contributors <meta@public-inbox.org>
+# Copyright (C) 2016-2020 all contributors <meta@public-inbox.org>
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 
 # Like most Perl modules in public-inbox, this is internal and
@@ -27,7 +27,6 @@ package PublicInbox::Qspawn;
 use strict;
 use warnings;
 use PublicInbox::Spawn qw(popen_rd);
-require Plack::Util;
 
 # n.b.: we get EAGAIN with public-inbox-httpd, and EINTR on other PSGI servers
 use Errno qw(EAGAIN EINTR);
@@ -36,32 +35,38 @@ my $def_limiter;
 
 # declares a command to spawn (but does not spawn it).
 # $cmd is the command to spawn
-# $env is the environ for the child process
+# $cmd_env is the environ for the child process (not PSGI env)
 # $opt can include redirects and perhaps other process spawning options
 sub new ($$$;) {
-	my ($class, $cmd, $env, $opt) = @_;
-	bless { args => [ $cmd, $env, $opt ] }, $class;
+	my ($class, $cmd, $cmd_env, $opt) = @_;
+	bless { args => [ $cmd, $cmd_env, $opt ] }, $class;
 }
 
 sub _do_spawn {
-	my ($self, $cb) = @_;
+	my ($self, $start_cb, $limiter) = @_;
 	my $err;
-	my ($cmd, $env, $opts) = @{$self->{args}};
-	my %opts = %{$opts || {}};
-	my $limiter = $self->{limiter};
+	my ($cmd, $cmd_env, $opt) = @{$self->{args}};
+	my %o = %{$opt || {}};
+	$self->{limiter} = $limiter;
 	foreach my $k (PublicInbox::Spawn::RLIMITS()) {
 		if (defined(my $rlimit = $limiter->{$k})) {
-			$opts{$k} = $rlimit;
+			$o{$k} = $rlimit;
 		}
 	}
+	eval {
+		# popen_rd may die on EMFILE, ENFILE
+		($self->{rpipe}, $self->{pid}) = popen_rd($cmd, $cmd_env, \%o);
+		$self->{args} = $o{quiet} ? undef : $cmd;
+
+		die "E: $!" unless defined($self->{pid});
 
-	($self->{rpipe}, $self->{pid}) = popen_rd($cmd, $env, \%opts);
-	if (defined $self->{pid}) {
 		$limiter->{running}++;
-	} else {
-		$self->{err} = $!;
+		$start_cb->($self); # EPOLL_CTL_ADD may ENOSPC/ENOMEM
+	};
+	if ($@) {
+		$self->{err} = $@;
+		finish($self);
 	}
-	$cb->($self->{rpipe});
 }
 
 sub child_err ($) {
@@ -73,43 +78,109 @@ sub child_err ($) {
 	$msg;
 }
 
-sub finish ($) {
-	my ($self) = @_;
+sub log_err ($$) {
+	my ($env, $msg) = @_;
+	$env->{'psgi.errors'}->print($msg, "\n");
+}
+
+# callback for dwaitpid
+sub waitpid_err ($$) {
+	my ($self, $pid) = @_;
+	my $xpid = delete $self->{pid};
+	my $err;
+	if ($pid > 0) { # success!
+		$err = child_err($?);
+	} elsif ($pid < 0) { # ??? does this happen in our case?
+		$err = "W: waitpid($xpid, 0) => $pid: $!";
+	} # else should not be called with pid == 0
+
+	my ($env, $qx_cb, $qx_arg, $qx_buf) =
+		delete @$self{qw(psgi_env qx_cb qx_arg qx_buf)};
+
+	# done, spawn whatever's in the queue
 	my $limiter = $self->{limiter};
-	my $running;
-	if (delete $self->{rpipe}) {
-		my $pid = delete $self->{pid};
-		$self->{err} = $pid == waitpid($pid, 0) ? child_err($?) :
-				"PID:$pid still running?";
-		$running = --$limiter->{running};
+	my $running = --$limiter->{running};
+
+	if ($running < $limiter->{max}) {
+		if (my $next = shift(@{$limiter->{run_queue}})) {
+			_do_spawn(@$next, $limiter);
+		}
 	}
 
-	# limiter->{max} may change dynamically
-	if (($running || $limiter->{running}) < $limiter->{max}) {
-		if (my $next = shift @{$limiter->{run_queue}}) {
-			_do_spawn(@$next);
+	if ($err) {
+		if ($self->{err}) {
+			$self->{err} .= "; $err";
+		} else {
+			$self->{err} = $err;
+		}
+		if ($env && $self->{args}) {
+			log_err($env, join(' ', @{$self->{args}}) . ": $err");
 		}
 	}
-	$self->{err};
+	eval { $qx_cb->($qx_buf, $qx_arg) } if $qx_cb;
 }
 
-sub start {
-	my ($self, $limiter, $cb) = @_;
-	$self->{limiter} = $limiter;
+sub do_waitpid ($) {
+	my ($self) = @_;
+	my $pid = $self->{pid};
+	# PublicInbox::DS may not be loaded
+	eval { PublicInbox::DS::dwaitpid($pid, \&waitpid_err, $self) };
+	# done if we're running in PublicInbox::DS::EventLoop
+	if ($@) {
+		# non public-inbox-{httpd,nntpd} callers may block:
+		my $ret = waitpid($pid, 0);
+		waitpid_err($self, $ret);
+	}
+}
+
+sub finish ($) {
+	my ($self) = @_;
+	if (delete $self->{rpipe}) {
+		do_waitpid($self);
+	} else {
+		my ($env, $qx_cb, $qx_arg, $qx_buf) =
+			delete @$self{qw(psgi_env qx_cb qx_arg qx_buf)};
+		eval { $qx_cb->($qx_buf, $qx_arg) } if $qx_cb;
+	}
+}
 
+sub start ($$$) {
+	my ($self, $limiter, $start_cb) = @_;
 	if ($limiter->{running} < $limiter->{max}) {
-		_do_spawn($self, $cb);
+		_do_spawn($self, $start_cb, $limiter);
 	} else {
-		push @{$limiter->{run_queue}}, [ $self, $cb ];
+		push @{$limiter->{run_queue}}, [ $self, $start_cb ];
 	}
 }
 
-sub _psgi_finish ($$) {
-	my ($self, $env) = @_;
-	my $err = $self->finish;
-	if ($err && !$env->{'qspawn.quiet'}) {
-		$err = join(' ', @{$self->{args}->[0]}).": $err\n";
-		$env->{'psgi.errors'}->print($err);
+sub psgi_qx_init_cb {
+	my ($self) = @_;
+	my $async = delete $self->{async};
+	my ($r, $buf);
+	my $qx_fh = $self->{qx_fh};
+reread:
+	$r = sysread($self->{rpipe}, $buf, 65536);
+	if ($async) {
+		$async->async_pass($self->{psgi_env}->{'psgix.io'},
+					$qx_fh, \$buf);
+	} elsif (defined $r) {
+		$r ? (print $qx_fh $buf) : event_step($self, undef);
+	} else {
+		return if $! == EAGAIN; # try again when notified
+		goto reread if $! == EINTR;
+		event_step($self, $!);
+	}
+}
+
+sub psgi_qx_start {
+	my ($self) = @_;
+	if (my $async = $self->{psgi_env}->{'pi-httpd.async'}) {
+		# PublicInbox::HTTPD::Async->new(rpipe, $cb, cb_arg, $end_obj)
+		$self->{async} = $async->($self->{rpipe},
+					\&psgi_qx_init_cb, $self, $self);
+		# init_cb will call ->async_pass or ->close
+	} else { # generic PSGI
+		psgi_qx_init_cb($self) while $self->{qx_fh};
 	}
 }
 
@@ -118,49 +189,99 @@ sub _psgi_finish ($$) {
 # $env is the PSGI env.  As with ``/qx; only use this when output is small
 # and safe to slurp.
 sub psgi_qx {
-	my ($self, $env, $limiter, $qx_cb) = @_;
-	my $qx = PublicInbox::Qspawn::Qx->new;
-	my $end = sub {
-		_psgi_finish($self, $env);
-		eval { $qx_cb->($qx) };
-		$qx = undef;
-	};
-	my $rpipe; # comes from popen_rd
-	my $async = $env->{'pi-httpd.async'};
-	my $cb = sub {
-		my $r = sysread($rpipe, my $buf, 8192);
-		if ($async) {
-			$async->async_pass($env->{'psgix.io'}, $qx, \$buf);
-		} elsif (defined $r) {
-			$r ? $qx->write($buf) : $end->();
+	my ($self, $env, $limiter, $qx_cb, $qx_arg) = @_;
+	$self->{psgi_env} = $env;
+	my $qx_buf = '';
+	open(my $qx_fh, '+>', \$qx_buf) or die; # PerlIO::scalar
+	$self->{qx_cb} = $qx_cb;
+	$self->{qx_arg} = $qx_arg;
+	$self->{qx_fh} = $qx_fh;
+	$self->{qx_buf} = \$qx_buf;
+	$limiter ||= $def_limiter ||= PublicInbox::Qspawn::Limiter->new(32);
+	start($self, $limiter, \&psgi_qx_start);
+}
+
+# this is called on pipe EOF to reap the process, may be called
+# via PublicInbox::DS event loop OR via GetlineBody for generic
+# PSGI servers.
+sub event_step {
+	my ($self, $err) = @_; # $err: $!
+	log_err($self->{psgi_env}, "psgi_{return,qx} $err") if defined($err);
+	finish($self);
+	my ($fh, $qx_fh) = delete(@$self{qw(fh qx_fh)});
+	$fh->close if $fh; # async-only (psgi_return)
+}
+
+sub rd_hdr ($) {
+	my ($self) = @_;
+	# typically used for reading CGI headers
+	# we must loop until EAGAIN for EPOLLET in HTTPD/Async.pm
+	# We also need to check EINTR for generic PSGI servers.
+	my $ret;
+	my $total_rd = 0;
+	my $hdr_buf = $self->{hdr_buf};
+	my ($ph_cb, $ph_arg) = @{$self->{parse_hdr}};
+	do {
+		my $r = sysread($self->{rpipe}, $$hdr_buf, 4096,
+				length($$hdr_buf));
+		if (defined($r)) {
+			$total_rd += $r;
+			$ret = $ph_cb->($total_rd, $hdr_buf, $ph_arg);
 		} else {
-			return if $! == EAGAIN || $! == EINTR; # loop again
-			$end->();
+			# caller should notify us when it's ready:
+			return if $! == EAGAIN;
+			next if $! == EINTR; # immediate retry
+			log_err($self->{psgi_env}, "error reading header: $!");
+			$ret = [ 500, [], [ "Internal error\n" ] ];
 		}
-	};
-	$limiter ||= $def_limiter ||= PublicInbox::Qspawn::Limiter->new(32);
-	$self->start($limiter, sub { # may run later, much later...
-		($rpipe) = @_; # popen_rd result
+	} until (defined $ret);
+	delete $self->{parse_hdr}; # done parsing headers
+	$ret;
+}
+
+sub psgi_return_init_cb {
+	my ($self) = @_;
+	my $r = rd_hdr($self) or return;
+	my $env = $self->{psgi_env};
+	my $wcb = delete $env->{'qspawn.wcb'};
+	my $async = delete $self->{async};
+	if (scalar(@$r) == 3) { # error
 		if ($async) {
-		# PublicInbox::HTTPD::Async->new($rpipe, $cb, $end)
-			$async = $async->($rpipe, $cb, $end);
-		} else { # generic PSGI
-			$cb->() while $qx;
+			# calls rpipe->close && ->event_step
+			$async->close;
+		} else {
+			$self->{rpipe}->close;
+			event_step($self);
 		}
-	});
+		$wcb->($r);
+	} elsif ($async) {
+		# done reading headers, handoff to read body
+		my $fh = $wcb->($r); # scalar @$r == 2
+		$self->{fh} = $fh;
+		$async->async_pass($env->{'psgix.io'}, $fh,
+					delete($self->{hdr_buf}));
+	} else { # for synchronous PSGI servers
+		require PublicInbox::GetlineBody;
+		$r->[2] = PublicInbox::GetlineBody->new($self->{rpipe},
+					\&event_step, $self,
+					${$self->{hdr_buf}});
+		$wcb->($r);
+	}
+
+	# Workaround a leak under Perl 5.16.3 when combined with
+	# Plack::Middleware::Deflater:
+	$wcb = undef;
 }
 
-# create a filter for "push"-based streaming PSGI writes used by HTTPD::Async
-sub filter_fh ($$) {
-	my ($fh, $filter) = @_;
-	Plack::Util::inline_object(
-		close => sub {
-			$fh->write($filter->(undef));
-			$fh->close;
-		},
-		write => sub {
-			$fh->write($filter->($_[0]));
-		});
+sub psgi_return_start { # may run later, much later...
+	my ($self) = @_;
+	if (my $async = $self->{psgi_env}->{'pi-httpd.async'}) {
+		# PublicInbox::HTTPD::Async->new(rpipe, $cb, $cb_arg, $end_obj)
+		$self->{async} = $async->($self->{rpipe},
+					\&psgi_return_init_cb, $self, $self);
+	} else { # generic PSGI
+		psgi_return_init_cb($self) while $self->{parse_hdr};
+	}
 }
 
 # Used for streaming the stdout of one process as a PSGI response.
@@ -173,9 +294,6 @@ sub filter_fh ($$) {
 #                          psgi_return will return an anonymous
 #                          sub for the PSGI server to call
 #
-#   $env->{'qspawn.filter'} - filter callback, receives a string as input,
-#                             undef on EOF
-#
 # $limiter - the Limiter object to use (uses the def_limiter if not given)
 #
 # $parse_hdr - Initial read function; often for parsing CGI header output.
@@ -186,69 +304,25 @@ sub filter_fh ($$) {
 #              psgix.io.  3-element arrays means the body is available
 #              immediately (or streamed via ->getline (pull-based)).
 sub psgi_return {
-	my ($self, $env, $limiter, $parse_hdr) = @_;
-	my ($fh, $rpipe);
-	my $end = sub {
-		_psgi_finish($self, $env);
-		$fh->close if $fh; # async-only
-	};
-
-	my $buf = '';
-	my $rd_hdr = sub {
-		my $r = sysread($rpipe, $buf, 1024, length($buf));
-		return if !defined($r) && $! == EAGAIN || $! == EINTR;
-		$parse_hdr->($r, \$buf);
-	};
-
-	my $wcb = delete $env->{'qspawn.wcb'};
-	my $async = $env->{'pi-httpd.async'};
-
-	my $cb = sub {
-		my $r = $rd_hdr->() or return;
-		$rd_hdr = undef;
-		my $filter = delete $env->{'qspawn.filter'};
-		if (scalar(@$r) == 3) { # error
-			if ($async) {
-				$async->close; # calls rpipe->close and $end
-			} else {
-				$rpipe->close;
-				$end->();
-			}
-			$wcb->($r);
-		} elsif ($async) {
-			$fh = $wcb->($r); # scalar @$r == 2
-			$fh = filter_fh($fh, $filter) if $filter;
-			$async->async_pass($env->{'psgix.io'}, $fh, \$buf);
-		} else { # for synchronous PSGI servers
-			require PublicInbox::GetlineBody;
-			$r->[2] = PublicInbox::GetlineBody->new($rpipe, $end,
-								$buf, $filter);
-			$wcb->($r);
-		}
-	};
+	my ($self, $env, $limiter, $parse_hdr, $hdr_arg) = @_;
+	$self->{psgi_env} = $env;
+	$self->{hdr_buf} = \(my $hdr_buf = '');
+	$self->{parse_hdr} = [ $parse_hdr, $hdr_arg ];
 	$limiter ||= $def_limiter ||= PublicInbox::Qspawn::Limiter->new(32);
-	my $start_cb = sub { # may run later, much later...
-		($rpipe) = @_;
-		if ($async) {
-			# PublicInbox::HTTPD::Async->new($rpipe, $cb, $end)
-			$async = $async->($rpipe, $cb, $end);
-		} else { # generic PSGI
-			$cb->() while $rd_hdr;
-		}
-	};
 
 	# the caller already captured the PSGI write callback from
 	# the PSGI server, so we can call ->start, here:
-	return $self->start($limiter, $start_cb) if $wcb;
+	$env->{'qspawn.wcb'} and
+		return start($self, $limiter, \&psgi_return_start);
 
 	# the caller will return this sub to the PSGI server, so
-	# it can set the response callback (that is, for PublicInbox::HTTP,
-	# the chunked_wcb or identity_wcb callback), but other HTTP servers
-	# are supported:
+	# it can set the response callback (that is, for
+	# PublicInbox::HTTP, the chunked_wcb or identity_wcb callback),
+	# but other HTTP servers are supported:
 	sub {
-		($wcb) = @_;
-		$self->start($limiter, $start_cb);
-	};
+		$env->{'qspawn.wcb'} = $_[0];
+		start($self, $limiter, \&psgi_return_start);
+	}
 }
 
 package PublicInbox::Qspawn::Limiter;
@@ -294,21 +368,4 @@ sub setup_rlimit {
 	}
 }
 
-# captures everything into a buffer and executes a callback when done
-package PublicInbox::Qspawn::Qx;
-use strict;
-use warnings;
-
-sub new {
-	my ($class) = @_;
-	my $buf = '';
-	bless \$buf, $class;
-}
-
-# called by PublicInbox::HTTPD::Async ($fh->write)
-sub write {
-	${$_[0]} .= $_[1];
-	undef;
-}
-
 1;