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From: Eric Wong <e@80x24.org>
To: spew@80x24.org
Subject: [PATCH] input_pipe: error handling + TTY support
Date: Mon, 16 Oct 2023 11:09:38 +0000
Message-ID: <20231016110938.1206501-1-e@80x24.org>
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List-Id: <spew.80x24.org>

---
 lib/PublicInbox/InputPipe.pm | 69 +++++++++++++++++++++++++++---------
 1 file changed, 53 insertions(+), 16 deletions(-)

diff --git a/lib/PublicInbox/InputPipe.pm b/lib/PublicInbox/InputPipe.pm
index 60a9f01f..5f109886 100644
--- a/lib/PublicInbox/InputPipe.pm
+++ b/lib/PublicInbox/InputPipe.pm
@@ -5,31 +5,68 @@
 package PublicInbox::InputPipe;
 use v5.12;
 use parent qw(PublicInbox::DS);
-use PublicInbox::Syscall qw(EPOLLIN EPOLLET);
+use PublicInbox::Syscall qw(EPOLLIN);
+use POSIX ();
+
+sub unblock_tty ($) {
+	my ($self) = @_;
+	my $t = POSIX::Termios->new;
+	my $fd = fileno(my $in = $self->{sock});
+	$t->getattr($fd) or croak("tcgetattr($in/$fd): $!");
+	my $vmin = $t->getcc(POSIX::VMIN);
+	my $vtime = $t->getcc(POSIX::VTIME);
+	return if $vmin == 1 && $vtime == 0;
+	$t->setcc(POSIX::VMIN, 1);
+	$t->setcc(POSIX::VTIME, 0);
+	$t->setattr($fd, POSIX::TCSANOW) or croak("tcsetattr($in/$fd): $!");
+	$t->setcc(POSIX::VMIN, $vmin);
+	$t->setcc(POSIX::VTIME, $vtime);
+	$self->{termios} = $t;
+}
 
 sub consume {
 	my ($in, $cb, @args) = @_;
 	my $self = bless { cb => $cb, args => \@args }, __PACKAGE__;
-	eval { $self->SUPER::new($in, EPOLLIN|EPOLLET) };
-	return $self->requeue if $@; # regular file
-	$in->blocking(0); # pipe or socket
+	eval { $self->SUPER::new($in, EPOLLIN) };
+	if ($@) {
+		$self->{-need_rq} = 1;
+		$self->requeue;
+	} elsif (-p $in || -s _) {
+		$in->blocking(0);
+	} elsif (-t _) { # not sure I know what I'm doing w/ terminals
+		unblock_tty($self);
+	}
+}
+
+sub close {
+	my ($self) = @_;
+	if (my $t = delete($self->{termios})) {
+		my $fd = fileno(my $in = $self->{sock} // return);
+		$t->setattr($fd, POSIX::TCSANOW) or
+				croak("tcsetattr($in/$fd): $!");
+	}
+	$self->{-need_rq} ? delete($self->{sock}) : $self->SUPER::close
 }
 
 sub event_step {
 	my ($self) = @_;
 	my $r = sysread($self->{sock} // return, my $rbuf, 65536);
-	if ($r) {
-		$self->{cb}->(@{$self->{args}}, $rbuf);
-		return $self->requeue; # may be regular file or pipe
-	}
-	if (defined($r)) { # EOF
-		$self->{cb}->(@{$self->{args}}, '');
-	} elsif ($!{EAGAIN}) {
-		return;
-	} else { # another error
-		$self->{cb}->(@{$self->{args}}, undef)
-	}
-	$self->{sock}->blocking ? delete($self->{sock}) : $self->close
+	eval {
+		if ($r) {
+			$self->{cb}->(@{$self->{args}}, $rbuf);
+			$self->requeue if $self->{-need_rq};
+		} elsif (defined($r)) { # EOF
+			$self->{cb}->(@{$self->{args}}, '');
+			$self->close
+		} elsif ($!{EAGAIN}) { # rely on EPOLLIN
+		} elsif ($!{EINTR}) { # rely on EPOLLIN for sockets/pipes/tty
+			$self->requeue if $self->{-need_rq};
+		} else { # another error
+			$self->{cb}->(@{$self->{args}}, undef);
+			$self->close;
+		}
+	};
+	$self->close if $@;
 }
 
 1;