From ffd40d6260b01290b2dd060f69ed2c663eba4027 Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Thu, 24 Sep 2015 21:28:51 +0000 Subject: nntpd: hoist out daemon management code We'll probably be supporting read-only IMAP, or maybe we'll just implement a custom HTTP server so users can manage/upgrade the same way as the nntpd while being immune to slow clients. --- lib/PublicInbox/Daemon.pm | 388 ++++++++++++++++++++++++++++++++++++++++++++ lib/PublicInbox/Listener.pm | 34 ++++ 2 files changed, 422 insertions(+) create mode 100644 lib/PublicInbox/Daemon.pm create mode 100644 lib/PublicInbox/Listener.pm (limited to 'lib') diff --git a/lib/PublicInbox/Daemon.pm b/lib/PublicInbox/Daemon.pm new file mode 100644 index 00000000..81ff21cd --- /dev/null +++ b/lib/PublicInbox/Daemon.pm @@ -0,0 +1,388 @@ +# Copyright (C) 2015 all contributors +# License: AGPLv3 or later (https://www.gnu.org/licenses/agpl-3.0.txt) +package PublicInbox::Daemon; # empty class :p + +# contains common daemon code for the nntpd server. +# This may be used for read-only IMAP server if we decide to implement it. +package main; +use strict; +use warnings; +use Getopt::Long qw/:config gnu_getopt no_ignore_case auto_abbrev/; +require Danga::Socket; +require POSIX; +require PublicInbox::Listener; +my @CMD; +my $set_user; +my (@cfg_listen, $stdout, $stderr, $group, $user, $pid_file, $daemonize); +my $worker_processes = 0; +my @listeners; +my %pids; +my %listener_names; +my $reexec_pid; +my $cleanup; +END { $cleanup->() if $cleanup }; + +sub daemon_prepare ($) { + my ($default_listen) = @_; + @CMD = ($0, @ARGV); + $SIG{HUP} = $SIG{USR1} = $SIG{USR2} = $SIG{PIPE} = + $SIG{TTIN} = $SIG{TTOU} = $SIG{WINCH} = 'IGNORE'; + my %opts = ( + 'l|listen=s' => \@cfg_listen, + '1|stdout=s' => \$stdout, + '2|stderr=s' => \$stderr, + 'W|worker-processes=i' => \$worker_processes, + 'P|pid-file=s' => \$pid_file, + 'u|user=s' => \$user, + 'g|group=s' => \$group, + 'D|daemonize' => \$daemonize, + ); + GetOptions(%opts) or die "bad command-line args\n"; + + if (defined $pid_file && $pid_file =~ /\.oldbin\z/) { + die "--pid-file cannot end with '.oldbin'\n"; + } + @listeners = inherit(); + # ignore daemonize when inheriting + $daemonize = undef if scalar @listeners; + + push @cfg_listen, $default_listen unless (@listeners || @cfg_listen); + + foreach my $l (@cfg_listen) { + next if $listener_names{$l}; # already inherited + require IO::Socket::INET6; # works for IPv4, too + my %o = ( + LocalAddr => $l, + ReuseAddr => 1, + Proto => 'tcp', + ); + if (my $s = IO::Socket::INET6->new(%o)) { + $listener_names{sockname($s)} = $s; + push @listeners, $s; + } else { + warn "error binding $l: $!\n"; + } + } + die 'No listeners bound' unless @listeners; +} + +sub daemonize () { + chdir '/' or die "chdir failed: $!\n"; + open(STDIN, '+<', '/dev/null') or die "redirect stdin failed: $!\n"; + + return unless (defined $pid_file || defined $group || defined $user + || $daemonize); + + require Net::Server::Daemonize; + + Net::Server::Daemonize::check_pid_file($pid_file) if defined $pid_file; + my $uid = Net::Server::Daemonize::get_uid($user) if defined $user; + my $gid; + if (defined $group) { + $gid = Net::Server::Daemonize::get_gid($group); + $gid = (split /\s+/, $gid)[0]; + } elsif (defined $uid) { + $gid = (getpwuid($uid))[3]; + } + + # We change users in the worker to ensure upgradability, + # The upgrade will create the ".oldbin" pid file in the + # same directory as the given pid file. + $uid and $set_user = sub { + Net::Server::Daemonize::set_user($uid, $gid); + }; + + if ($daemonize) { + my ($pid, $err) = do_fork(); + die "could not fork: $err\n" unless defined $pid; + exit if $pid; + + open STDOUT, '>&STDIN' or die "redirect stdout failed: $!\n"; + open STDERR, '>&STDIN' or die "redirect stderr failed: $!\n"; + POSIX::setsid(); + ($pid, $err) = do_fork(); + die "could not fork: $err\n" unless defined $pid; + exit if $pid; + } + if (defined $pid_file) { + Net::Server::Daemonize::create_pid_file($pid_file); + if ($uid and !chown($uid, $gid, $pid_file)) { + warn "could not chown $pid_file: $!\n"; + } + my $unlink_pid = $$; + $cleanup = sub { + unlink_pid_file_safe_ish($unlink_pid, $pid_file); + }; + } +} + +sub worker_quit () { + # killing again terminates immediately: + exit unless @listeners; + + @listeners = (); + + # give slow clients 30s to finish reading/writing whatever + Danga::Socket->AddTimer(30, sub { exit }); + + # drop idle connections and try to quit gracefully + Danga::Socket->SetPostLoopCallback(sub { + my ($dmap, undef) = @_; + my $n = 0; + + foreach my $s (values %$dmap) { + if ($s->can('busy') && $s->busy) { + $n = 1; + } else { + # close as much as possible, early as possible + $s->close; + } + } + $n; # true: loop continues, false: loop breaks + }); +} + +sub reopen_logs { + if ($stdout) { + open STDOUT, '>>', $stdout or + warn "failed to redirect stdout to $stdout: $!\n"; + } + if ($stderr) { + open STDERR, '>>', $stderr or + warn "failed to redirect stderr to $stderr: $!\n"; + } +} + +sub sockname ($) { + my ($s) = @_; + my $n = getsockname($s) or return; + my ($port, $addr); + if (length($n) >= 28) { + require Socket6; + ($port, $addr) = Socket6::unpack_sockaddr_in6($n); + } else { + ($port, $addr) = Socket::sockaddr_in($n); + } + if (length($addr) == 4) { + $n = Socket::inet_ntoa($addr) + } else { + $n = '['.Socket6::inet_ntop(Socket6::AF_INET6(), $addr).']'; + } + $n .= ":$port"; +} + +sub inherit () { + return () if ($ENV{LISTEN_PID} || 0) != $$; + my $fds = $ENV{LISTEN_FDS} or return (); + my $end = $fds + 2; # LISTEN_FDS_START - 1 + my @rv = (); + foreach my $fd (3..$end) { + my $s = IO::Handle->new; + $s->fdopen($fd, 'r'); + if (my $k = sockname($s)) { + $listener_names{$k} = $s; + push @rv, $s; + } else { + warn "failed to inherit fd=$fd (LISTEN_FDS=$fds)"; + } + } + @rv +} + +sub upgrade () { + if ($reexec_pid) { + warn "upgrade in-progress: $reexec_pid\n"; + return; + } + if (defined $pid_file) { + if ($pid_file =~ /\.oldbin\z/) { + warn "BUG: .oldbin suffix exists: $pid_file\n"; + return; + } + unlink_pid_file_safe_ish($$, $pid_file); + $pid_file .= '.oldbin'; + Net::Server::Daemonize::create_pid_file($pid_file); + } + my ($pid, $err) = do_fork(); + unless (defined $pid) { + warn "fork failed: $err\n"; + return; + } + if ($pid == 0) { + use Fcntl qw(FD_CLOEXEC F_SETFD F_GETFD); + $ENV{LISTEN_FDS} = scalar @listeners; + $ENV{LISTEN_PID} = $$; + foreach my $s (@listeners) { + my $fl = fcntl($s, F_GETFD, 0); + fcntl($s, F_SETFD, $fl &= ~FD_CLOEXEC); + } + exec @CMD; + die "Failed to exec: $!\n"; + } + $reexec_pid = $pid; +} + +sub kill_workers ($) { + my ($s) = @_; + + while (my ($pid, $id) = each %pids) { + kill $s, $pid; + } +} + +sub do_fork () { + my $new = POSIX::SigSet->new; + $new->fillset; + my $old = POSIX::SigSet->new; + POSIX::sigprocmask(&POSIX::SIG_BLOCK, $new, $old) or + die "SIG_BLOCK: $!\n"; + my $pid = fork; + my $err = $!; + POSIX::sigprocmask(&POSIX::SIG_SETMASK, $old) or + die "SIG_SETMASK: $!\n"; + ($pid, $err); +} + +sub upgrade_aborted ($) { + my ($p) = @_; + warn "reexec PID($p) died with: $?\n"; + $reexec_pid = undef; + return unless $pid_file; + + my $file = $pid_file; + $file =~ s/\.oldbin\z// or die "BUG: no '.oldbin' suffix in $file\n"; + unlink_pid_file_safe_ish($$, $pid_file); + $pid_file = $file; + eval { Net::Server::Daemonize::create_pid_file($pid_file) }; + warn $@, "\n" if $@; +} + +sub reap_children () { + while (1) { + my $p = waitpid(-1, &POSIX::WNOHANG) or return; + if (defined $reexec_pid && $p == $reexec_pid) { + upgrade_aborted($p); + } elsif (defined(my $id = delete $pids{$p})) { + warn "worker[$id] PID($p) died with: $?\n"; + } elsif ($p > 0) { + warn "unknown PID($p) reaped: $?\n"; + } else { + return; + } + } +} + +sub unlink_pid_file_safe_ish ($$) { + my ($unlink_pid, $file) = @_; + return unless defined $unlink_pid && $unlink_pid == $$; + + open my $fh, '<', $file or return; + defined(my $read_pid = <$fh>) or return; + chomp $read_pid; + if ($read_pid == $unlink_pid) { + Net::Server::Daemonize::unlink_pid_file($file); + } +} + +sub master_loop ($) { + my ($refresh) = @_; + pipe(my ($p0, $p1)) or die "failed to create parent-pipe: $!\n"; + my %pwatch = ( fileno($p0) => sub { kill('TERM', $$) } ); + pipe(my ($r, $w)) or die "failed to create self-pipe: $!\n"; + IO::Handle::blocking($w, 0); + my $set_workers = $worker_processes; + my @caught; + my $master_pid = $$; + foreach my $s (qw(HUP CHLD QUIT INT TERM USR1 USR2 TTIN TTOU WINCH)) { + $SIG{$s} = sub { + return if $$ != $master_pid; + push @caught, $s; + syswrite($w, '.'); + }; + } + reopen_logs(); + # main loop + while (1) { + while (my $s = shift @caught) { + if ($s eq 'USR1') { + reopen_logs(); + kill_workers($s); + } elsif ($s eq 'USR2') { + upgrade(); + } elsif ($s =~ /\A(?:QUIT|TERM|INT)\z/) { + # drops pipes and causes children to die + exit + } elsif ($s eq 'WINCH') { + $worker_processes = 0; + } elsif ($s eq 'HUP') { + $worker_processes = $set_workers; + $refresh->(); + kill_workers($s); + } elsif ($s eq 'TTIN') { + if ($set_workers > $worker_processes) { + ++$worker_processes; + } else { + $worker_processes = ++$set_workers; + } + } elsif ($s eq 'TTOU') { + if ($set_workers > 0) { + $worker_processes = --$set_workers; + } + } elsif ($s eq 'CHLD') { + reap_children(); + } + } + + my $n = scalar keys %pids; + if ($n > $worker_processes) { + while (my ($k, $v) = each %pids) { + kill('TERM', $k) if $v >= $worker_processes; + } + $n = $worker_processes; + } + foreach my $i ($n..($worker_processes - 1)) { + my ($pid, $err) = do_fork(); + if (!defined $pid) { + warn "failed to fork worker[$i]: $err\n"; + } elsif ($pid == 0) { + $set_user->() if $set_user; + close($_) for ($w, $r, $p1); + Danga::Socket->AddOtherFds(%pwatch); + return; # run normal work code + } else { + warn "PID=$pid is worker[$i]\n"; + $pids{$pid} = $i; + } + } + # just wait on signal events here: + sysread($r, my $buf, 8); + } + exit # never gets here, just for documentation +} + +sub daemon_loop ($$) { + my ($refresh, $post_accept) = @_; + $refresh->(); # load config before forking to save work + if ($worker_processes > 0) { + master_loop($refresh); # returns if in child process + } else { + $set_user->() if $set_user; + $SIG{USR2} = sub { worker_quit() if upgrade() }; + } + reopen_logs(); + $SIG{QUIT} = $SIG{INT} = $SIG{TERM} = *worker_quit; + $SIG{USR1} = *reopen_logs; + $SIG{HUP} = $refresh; + # this calls epoll_create: + PublicInbox::Listener->new($_, $post_accept) for @listeners; + Danga::Socket->EventLoop; +} + + +sub daemon_run ($$$) { + my ($default, $refresh, $post_accept) = @_; + daemon_prepare($default); + daemon_loop($refresh, $post_accept); +} + +1; diff --git a/lib/PublicInbox/Listener.pm b/lib/PublicInbox/Listener.pm new file mode 100644 index 00000000..7f9658b8 --- /dev/null +++ b/lib/PublicInbox/Listener.pm @@ -0,0 +1,34 @@ +# Copyright (C) 2015 all contributors +# License: AGPLv3 or later (https://www.gnu.org/licenses/agpl-3.0.txt) +package PublicInbox::Listener; +use strict; +use warnings; +use base 'Danga::Socket'; +use Socket qw(SOL_SOCKET SO_KEEPALIVE IPPROTO_TCP TCP_NODELAY); +use fields qw(post_accept); +require IO::Handle; + +sub new ($$$) { + my ($class, $s, $cb) = @_; + setsockopt($s, SOL_SOCKET, SO_KEEPALIVE, 1); + setsockopt($s, IPPROTO_TCP, TCP_NODELAY, 1); + listen($s, 1024); + IO::Handle::blocking($s, 0); + my $self = fields::new($class); + $self->SUPER::new($s); # calls epoll_create for the first socket + $self->watch_read(1); + $self->{post_accept} = $cb; + $self +} + +sub event_read { + my ($self) = @_; + # no loop here, we want to fairly distribute clients + # between multiple processes sharing the same socket + if (accept(my $c, $self->{sock})) { + IO::Handle::blocking($c, 0); # no accept4 :< + $self->{post_accept}->($c); + } +} + +1; -- cgit v1.2.3-24-ge0c7