From 687f579ab401cc9ddf63e9901c37c37ab7d4eef1 Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Tue, 28 Mar 2023 11:12:36 +0000 Subject: inotify: wrap with informative error message As encountered by Louis DeLosSantos, Linux inotify is capped by a lesser-known limit than the standard RLIMIT_NOFILE (`ulimit -n`) value. Give the user a hint about the fs.inotify.max_user_instances sysctl knob on EMFILE, since EMFILE alone may mislead users into thinking they've hit the (typically higher) RLIMIT_NOFILE limit. I can test this on my system using: perl -I lib -MPublicInbox::Inotify -E \ 'my @x = map { PublicInbox::Inotify->new } (1..128)' But I hesitate to include it in the test suite since triggering the limit can cause unrelated processes to fail. Link: https://public-inbox.org/meta/CAE6jdTo8iQfNM9Yuk0Dwi-ARMxmQxX-onL8buXcQ9Ze3r0hKrg@mail.gmail.com/ Reported-by: Louis DeLosSantos --- MANIFEST | 1 + lib/PublicInbox/DirIdle.pm | 4 ++-- lib/PublicInbox/InboxIdle.pm | 4 ++-- lib/PublicInbox/Inotify.pm | 30 ++++++++++++++++++++++++++++++ 4 files changed, 35 insertions(+), 4 deletions(-) create mode 100644 lib/PublicInbox/Inotify.pm diff --git a/MANIFEST b/MANIFEST index 40535233..3c421645 100644 --- a/MANIFEST +++ b/MANIFEST @@ -217,6 +217,7 @@ lib/PublicInbox/In2Tie.pm lib/PublicInbox/Inbox.pm lib/PublicInbox/InboxIdle.pm lib/PublicInbox/InboxWritable.pm +lib/PublicInbox/Inotify.pm lib/PublicInbox/InputPipe.pm lib/PublicInbox/Isearch.pm lib/PublicInbox/KQNotify.pm diff --git a/lib/PublicInbox/DirIdle.pm b/lib/PublicInbox/DirIdle.pm index 55c3982f..af99811c 100644 --- a/lib/PublicInbox/DirIdle.pm +++ b/lib/PublicInbox/DirIdle.pm @@ -9,14 +9,14 @@ use PublicInbox::Syscall qw(EPOLLIN); use PublicInbox::In2Tie; my ($MAIL_IN, $MAIL_GONE, $ino_cls); -if ($^O eq 'linux' && eval { require Linux::Inotify2; 1 }) { +if ($^O eq 'linux' && eval { require PublicInbox::Inotify; 1 }) { $MAIL_IN = Linux::Inotify2::IN_MOVED_TO() | Linux::Inotify2::IN_CREATE(); $MAIL_GONE = Linux::Inotify2::IN_DELETE() | Linux::Inotify2::IN_DELETE_SELF() | Linux::Inotify2::IN_MOVE_SELF() | Linux::Inotify2::IN_MOVED_FROM(); - $ino_cls = 'Linux::Inotify2'; + $ino_cls = 'PublicInbox::Inotify'; # Perl 5.22+ is needed for fileno(DIRHANDLE) support: } elsif ($^V ge v5.22 && eval { require PublicInbox::KQNotify }) { $MAIL_IN = PublicInbox::KQNotify::MOVED_TO_OR_CREATE(); diff --git a/lib/PublicInbox/InboxIdle.pm b/lib/PublicInbox/InboxIdle.pm index f0d8a972..4231c0a0 100644 --- a/lib/PublicInbox/InboxIdle.pm +++ b/lib/PublicInbox/InboxIdle.pm @@ -10,9 +10,9 @@ use parent qw(PublicInbox::DS); use PublicInbox::Syscall qw(EPOLLIN); my $IN_MODIFY = 0x02; # match Linux inotify my $ino_cls; -if ($^O eq 'linux' && eval { require Linux::Inotify2; 1 }) { +if ($^O eq 'linux' && eval { require PublicInbox::Inotify }) { $IN_MODIFY = Linux::Inotify2::IN_MODIFY(); - $ino_cls = 'Linux::Inotify2'; + $ino_cls = 'PublicInbox::Inotify'; } elsif (eval { require PublicInbox::KQNotify }) { $IN_MODIFY = PublicInbox::KQNotify::NOTE_WRITE(); $ino_cls = 'PublicInbox::KQNotify'; diff --git a/lib/PublicInbox/Inotify.pm b/lib/PublicInbox/Inotify.pm new file mode 100644 index 00000000..3ef271c8 --- /dev/null +++ b/lib/PublicInbox/Inotify.pm @@ -0,0 +1,30 @@ +# Copyright (C) all contributors +# License: AGPL-3.0+ + +# wrap Linux::Inotify2 XS module, support pure Perl via `syscall' someday +package PublicInbox::Inotify; +use v5.12; +our @ISA; +BEGIN { + eval { require Linux::Inotify2 }; + if ($@) { # TODO: get rid of XS dependency + die "W: Linux::Inotify2 missing: $@\n"; + } else { + push @ISA, 'Linux::Inotify2'; + } +}; + +sub new { + $_[0]->SUPER::new // do { + my $msg = $!{EMFILE} ? <new: $!\n"; +inotify_init/inotify_init1: $! +You may need to raise the `fs.inotify.max_user_instances' sysctl limit. +Consult your OS documentation and/or sysctl(8) + sysctl.conf(5) manpages. +EOM + $msg =~ s/^/E: /smg; + require Carp; + Carp::croak($msg); + } +} + +1; -- cgit v1.2.3-24-ge0c7