From: Eric Wong <e@80x24.org>
To: meta@public-inbox.org
Subject: [PATCH 2/3] input_pipe: improve error handling
Date: Tue, 17 Oct 2023 10:11:05 +0000 [thread overview]
Message-ID: <20231017101106.582556-3-e@80x24.org> (raw)
In-Reply-To: <20231017101106.582556-1-e@80x24.org>
Ensure the callback is always guarded by `eval' to catch
exceptions and to force a ->close (EPOLL_CTL_DEL).
We also don't want to blindly set O_NONBLOCK on TTYs since their
O_NONBLOCK semantics aren't well-defined by POSIX. We can also
drop EPOLLET (edge-triggered) use to reduce the need to make
->requeue calls on our end.
---
lib/PublicInbox/InputPipe.pm | 48 ++++++++++++++++++++++++------------
1 file changed, 32 insertions(+), 16 deletions(-)
diff --git a/lib/PublicInbox/InputPipe.pm b/lib/PublicInbox/InputPipe.pm
index 60a9f01f..39aefab2 100644
--- a/lib/PublicInbox/InputPipe.pm
+++ b/lib/PublicInbox/InputPipe.pm
@@ -1,35 +1,51 @@
# Copyright (C) all contributors <meta@public-inbox.org>
# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
-# for reading pipes and sockets off the DS event loop
+# for reading pipes, sockets, and TTYs off the DS event loop
package PublicInbox::InputPipe;
use v5.12;
use parent qw(PublicInbox::DS);
-use PublicInbox::Syscall qw(EPOLLIN EPOLLET);
+use PublicInbox::Syscall qw(EPOLLIN);
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 ($@) { # regular file (but not w/ select|IO::Poll backends)
+ $self->{-need_rq} = 1;
+ $self->requeue;
+ } elsif (-p $in || -s _) { # O_NONBLOCK for sockets and pipes
+ $in->blocking(0);
+ } # TODO: tty
+}
+
+sub close {
+ my ($self) = @_;
+ $self->{-need_rq} ? delete($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)
+ 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);
+ $self->close;
+ }
+ };
+ if ($@) {
+ warn "E: $@";
+ $self->close;
}
- $self->{sock}->blocking ? delete($self->{sock}) : $self->close
}
1;
next prev parent reply other threads:[~2023-10-17 10:11 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-17 10:11 [PATCH 0/3] lei: stdin handling improvements Eric Wong
2023-10-17 10:11 ` [PATCH 1/3] lei: consolidate stdin slurp, fix warnings Eric Wong
2023-10-17 10:11 ` Eric Wong [this message]
2023-10-17 10:11 ` [RFC 3/3] input_pipe: handle noncanonical TTY Eric Wong
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://public-inbox.org/README
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20231017101106.582556-3-e@80x24.org \
--to=e@80x24.org \
--cc=meta@public-inbox.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).