1 # Copyright (C) 2019 all contributors <meta@public-inbox.org>
2 # Licensed the same as Danga::Socket (and Perl5)
3 # License: GPL-1.0+ or Artistic-1.0-Perl
4 # <https://www.gnu.org/licenses/gpl-1.0.txt>
5 # <https://dev.perl.org/licenses/artistic.html>
7 # kqueue support via IO::KQueue XS module. This makes kqueue look
8 # like epoll to simplify the code in DS.pm. This is NOT meant to be
9 # an all encompassing emulation of epoll via IO::KQueue, but just to
10 # support cases public-inbox-nntpd/httpd care about.
12 # It also implements signalfd(2) emulation via "tie".
14 # A pure-Perl version using syscall() is planned.
15 package PublicInbox::DSKQXS;
18 use parent qw(Exporter);
19 use Symbol qw(gensym);
22 use PublicInbox::Syscall qw(EPOLLONESHOT EPOLLIN EPOLLOUT EPOLLET
23 EPOLL_CTL_ADD EPOLL_CTL_MOD EPOLL_CTL_DEL SFD_NONBLOCK);
24 our @EXPORT_OK = qw(epoll_ctl epoll_wait);
26 sub EV_DISPATCH () { 0x0080 }
28 # map EPOLL* bits to kqueue EV_* flags for EV_SET
33 $fl |= EV_CLEAR if $fl & EPOLLET;
35 # EV_DISPATCH matches EPOLLONESHOT semantics more closely
36 # than EV_ONESHOT, in that EV_ADD is not required to
37 # re-enable a disabled watch.
38 ($ev & EPOLLONESHOT) ? ($fl | EV_DISPATCH) : $fl;
46 bless { kq => IO::KQueue->new, owner_pid => $$ }, $class;
49 # returns a new instance which behaves like signalfd on Linux.
50 # It's wasteful in that it uses another FD, but it simplifies
51 # our epoll-oriented code.
53 my ($class, $signo, $flags) = @_;
55 tie *$sym, $class, $signo, $flags; # calls TIEHANDLE
59 sub TIEHANDLE { # similar to signalfd()
60 my ($class, $signo, $flags) = @_;
61 my $self = $class->new;
62 $self->{timeout} = ($flags & SFD_NONBLOCK) ? 0 : -1;
64 $kq->EV_SET($_, EVFILT_SIGNAL, EV_ADD) for @$signo;
68 sub READ { # called by sysread() for signalfd compatibility
69 my ($self, undef, $len, $off) = @_; # $_[1] = buf
70 die "bad args for signalfd read" if ($len % 128) // defined($off);
71 my $timeout = $self->{timeout};
72 my $sigbuf = $self->{sigbuf} //= [];
78 my $signo = shift(@$sigbuf) or last;
79 # caller only cares about signalfd_siginfo.ssi_signo:
80 $_[1] .= pack('L', $signo) . ("\0" x 124);
84 my @events = eval { $self->{kq}->kevent($timeout) };
85 # workaround https://rt.cpan.org/Ticket/Display.html?id=116615
87 next if $@ =~ /Interrupted system call/;
90 if (!scalar(@events) && $timeout == 0) {
95 # Grab the kevent.ident (signal number). The kevent.data
96 # field shows coalesced signals, and maybe we'll use it
98 @$sigbuf = map { $_->[0] } @events;
102 # for fileno() calls in PublicInbox::DS
103 sub FILENO { ${$_[0]->{kq}} }
106 my ($self, $op, $fd, $ev) = @_;
107 my $kq = $self->{kq};
108 if ($op == EPOLL_CTL_MOD) {
109 $kq->EV_SET($fd, EVFILT_READ, kq_flag(EPOLLIN, $ev));
110 $kq->EV_SET($fd, EVFILT_WRITE, kq_flag(EPOLLOUT, $ev));
111 } elsif ($op == EPOLL_CTL_DEL) {
112 $kq->EV_SET($fd, EVFILT_READ, EV_DISABLE);
113 $kq->EV_SET($fd, EVFILT_WRITE, EV_DISABLE);
114 } else { # EPOLL_CTL_ADD
115 $kq->EV_SET($fd, EVFILT_READ, EV_ADD|kq_flag(EPOLLIN, $ev));
117 # we call this blindly for read-only FDs such as tied
118 # DSKQXS (signalfd emulation) and Listeners
120 $kq->EV_SET($fd, EVFILT_WRITE, EV_ADD |
121 kq_flag(EPOLLOUT, $ev));
128 my ($self, $maxevents, $timeout_msec, $events) = @_;
129 @$events = eval { $self->{kq}->kevent($timeout_msec) };
131 # workaround https://rt.cpan.org/Ticket/Display.html?id=116615
132 if ($err =~ /Interrupted system call/) {
138 # caller only cares for $events[$i]->[0]
142 # kqueue is close-on-fork (not exec), so we must not close it
143 # in forked processes:
146 my $kq = delete $self->{kq} or return;
147 if (delete($self->{owner_pid}) == $$) {