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authorEric Wong <e@yhbt.net>2020-06-27 10:03:37 +0000
committerEric Wong <e@yhbt.net>2020-06-28 22:27:14 +0000
commit58c0333adbdd9f5f82309cb6eef3c379f0ff064e (patch)
tree5e0d2304c4003fcd9c858db4b955abab7e6e3a8f /lib/PublicInbox/WatchMaildir.pm
parentb2b1006759730507731fcd3fc3e0de68239e3b92 (diff)
downloadpublic-inbox-58c0333adbdd9f5f82309cb6eef3c379f0ff064e.tar.gz
We can get rid of the janky wannabe
self-using-a-directory-instead-of-pipe thing we needed to
workaround Filesys::Notify::Simple being blocking.

For existing Maildir users, this should be more robust and
immune to missed wakeups for signalfd and kqueue-enabled
systems; as well as being immune to BOFHs clearing $TMPDIR
and preventing notifications from firing.

The IMAP IDLE code still uses normal Perl signals, so it's still
vulnerable to missed wakeups.  That will be addressed in future
commits.
Diffstat (limited to 'lib/PublicInbox/WatchMaildir.pm')
-rw-r--r--lib/PublicInbox/WatchMaildir.pm67
1 files changed, 37 insertions, 30 deletions
diff --git a/lib/PublicInbox/WatchMaildir.pm b/lib/PublicInbox/WatchMaildir.pm
index 22f19036..4d3cd032 100644
--- a/lib/PublicInbox/WatchMaildir.pm
+++ b/lib/PublicInbox/WatchMaildir.pm
@@ -8,9 +8,9 @@ use strict;
 use warnings;
 use PublicInbox::Eml;
 use PublicInbox::InboxWritable;
-use File::Temp 0.19 (); # 0.19 for ->newdir
 use PublicInbox::Filter::Base qw(REJECT);
 use PublicInbox::Spamcheck;
+use PublicInbox::Sigfd;
 use PublicInbox::DS qw(now);
 use POSIX qw(_exit WNOHANG);
 *mime_from_path = \&PublicInbox::InboxWritable::mime_from_path;
@@ -108,6 +108,7 @@ sub new {
                 imap => scalar keys %imap ? \%imap : undef,
                 importers => {},
                 opendirs => {}, # dirname => dirhandle (in progress scans)
+                ops => [], # 'quit', 'full'
         }, $class;
 }
 
@@ -195,7 +196,9 @@ sub _try_path {
 
 sub quit {
         my ($self) = @_;
-        trigger_scan($self, 'quit') or $self->{quit} = 1;
+        $self->{quit} = 1;
+        %{$self->{opendirs}} = ();
+        _done_for_now($self);
         if (my $imap_pid = $self->{-imap_pid}) {
                 kill('QUIT', $imap_pid);
         }
@@ -213,24 +216,15 @@ sub quit {
 sub watch_fs {
         my ($self) = @_;
         require PublicInbox::DirIdle;
-        my $scan = File::Temp->newdir("public-inbox-watch.$$.scan.XXXXXX",
-                                        TMPDIR => 1);
-        my $scandir = $self->{scandir} = $scan->dirname;
-        my $scan_re = qr!\A$scandir/!;
         my $done = sub {
                 delete $self->{done_timer};
                 _done_for_now($self);
         };
         my $cb = sub {
-                my $path = $_[0]->fullname;
-                if ($path =~ $scan_re) {
-                        scan($self, $path);
-                } else {
-                        _try_path($self, $path);
-                }
+                _try_path($self, $_[0]->fullname);
                 $self->{done_timer} //= PublicInbox::DS::requeue($done);
         };
-        my $di = PublicInbox::DirIdle->new([@{$self->{mdir}}, $scandir], $cb);
+        my $di = PublicInbox::DirIdle->new($self->{mdir}, $cb);
         PublicInbox::DS->SetPostLoopCallback(sub { !$self->{quit} });
         PublicInbox::DS->EventLoop;
         _done_for_now($self);
@@ -485,6 +479,12 @@ sub watch_imap_idle_1 ($$$) {
         }
 }
 
+sub watch_atfork_child ($) {
+        my ($self) = @_;
+        PublicInbox::Sigfd::sig_setmask($self->{oldset});
+        %SIG = (%SIG, %{$self->{sig}});
+}
+
 sub watch_imap_idle_all ($$) {
         my ($self, $idle) = @_; # $idle = [[ uri1, intvl1 ], [ uri2, intvl2 ]]
         $self->{mics} = {}; # going to be forking, so disconnect
@@ -494,6 +494,7 @@ sub watch_imap_idle_all ($$) {
                         my ($uri, $intvl) = @$uri_intvl;
                         defined(my $pid = fork) or die "fork: $!";
                         if ($pid == 0) {
+                                watch_atfork_child($self);
                                 delete $self->{idle_pids};
                                 watch_imap_idle_1($self, $uri, $intvl);
                                 _exit(0);
@@ -564,15 +565,20 @@ sub watch_imap ($) {
 }
 
 sub watch {
-        my ($self) = @_;
+        my ($self, $sig, $oldset) = @_;
+        $self->{oldset} = $oldset;
+        $self->{sig} = $sig;
         if ($self->{mdre} && $self->{imap}) {
                 defined(my $pid = fork) or die "fork: $!";
                 if ($pid == 0) {
+                        watch_atfork_child($self);
                         imap_start($self);
                         goto &watch_imap;
                 }
                 $self->{-imap_pid} = $pid;
         } elsif ($self->{imap}) {
+                # not a child process, but no signalfd, yet:
+                watch_atfork_child($self);
                 imap_start($self);
                 goto &watch_imap;
         }
@@ -580,23 +586,18 @@ sub watch {
 }
 
 sub trigger_scan {
-        my ($self, $base) = @_;
-        my $dir = $self->{scandir} or return;
-        open my $fh, '>', "$dir/$base" or die "open $dir/$base failed: $!\n";
-        close $fh or die "close $dir/$base failed: $!\n";
+        my ($self, $op) = @_;
+        push @{$self->{ops}}, $op;
+        PublicInbox::DS::requeue($self);
 }
 
-sub scan {
-        my ($self, $path) = @_;
-        if ($path =~ /quit\z/) {
-                %{$self->{opendirs}} = ();
-                _done_for_now($self);
-                delete $self->{scandir};
-                $self->{quit} = 1;
-                return;
-        }
-        # else: $path =~ /(cont|full)\z/
+# called directly, and by PublicInbox::DS
+sub event_step ($) {
+        my ($self) = @_;
         return if $self->{quit};
+        my $op = shift @{$self->{ops}};
+
+        # continue existing scan
         my $max = 10;
         my $opendirs = $self->{opendirs};
         my @dirnames = keys %$opendirs;
@@ -609,7 +610,7 @@ sub scan {
                 }
                 $opendirs->{$dir} = $dh if $n < 0;
         }
-        if ($path =~ /full\z/) {
+        if ($op && $op eq 'full') {
                 foreach my $dir (@{$self->{mdir}}) {
                         next if $opendirs->{$dir}; # already in progress
                         my $ok = opendir(my $dh, $dir);
@@ -627,7 +628,13 @@ sub scan {
         }
         _done_for_now($self);
         # do we have more work to do?
-        trigger_scan($self, 'cont') if keys %$opendirs;
+        PublicInbox::DS::requeue($self) if keys %$opendirs;
+}
+
+sub scan {
+        my ($self, $op) = @_;
+        push @{$self->{ops}}, $op;
+        goto &event_step;
 }
 
 sub _importer_for {