# Copyright (C) 2015-2021 all contributors
# License: AGPL-3.0+
#
# Contains common daemon code for the httpd, imapd, and nntpd servers
# and designed for handling thousands of untrusted clients over slow
# and/or lossy connections.
package PublicInbox::Daemon;
use strict;
use v5.10.1;
use Getopt::Long qw(:config gnu_getopt no_ignore_case auto_abbrev);
use IO::Handle; # ->autoflush
use IO::Socket;
use POSIX qw(WNOHANG :signal_h);
use Socket qw(IPPROTO_TCP SOL_SOCKET);
STDOUT->autoflush(1);
STDERR->autoflush(1);
use PublicInbox::DS qw(now);
use PublicInbox::Listener;
use PublicInbox::EOFpipe;
use PublicInbox::Sigfd;
use PublicInbox::Git;
use PublicInbox::GitAsyncCat;
use PublicInbox::Eml;
our $SO_ACCEPTFILTER = 0x1000;
my @CMD;
my ($set_user, $oldset);
my (@cfg_listen, $stdout, $stderr, $group, $user, $pid_file, $daemonize);
my $worker_processes = 1;
my @listeners;
my %pids;
my %tls_opt; # scheme://sockname => args for IO::Socket::SSL->start_SSL
my $reexec_pid;
my ($uid, $gid);
my ($default_cert, $default_key);
my %KNOWN_TLS = ( 443 => 'https', 563 => 'nntps', 993 => 'imaps' );
my %KNOWN_STARTTLS = ( 119 => 'nntp', 143 => 'imap' );
sub accept_tls_opt ($) {
my ($opt_str) = @_;
# opt_str: opt1=val1,opt2=val2 (opt may repeat for multi-value)
require PublicInbox::TLS;
my $o = {};
# allow ',' as delimiter since '&' is shell-unfriendly
foreach (split(/[,&]/, $opt_str)) {
my ($k, $v) = split(/=/, $_, 2);
push @{$o->{$k} ||= []}, $v;
}
# key may be a part of cert. At least
# p5-io-socket-ssl/example/ssl_server.pl has this fallback:
$o->{cert} //= [ $default_cert ];
$o->{key} //= defined($default_key) ? [ $default_key ] : $o->{cert};
my %ctx_opt = (SSL_server => 1);
# parse out hostname:/path/to/ mappings:
foreach my $k (qw(cert key)) {
my $x = $ctx_opt{'SSL_'.$k.'_file'} = {};
foreach my $path (@{$o->{$k}}) {
my $host = '';
$path =~ s/\A([^:]+):// and $host = $1;
$x->{$host} = $path;
}
}
my $ctx = IO::Socket::SSL::SSL_Context->new(%ctx_opt) or
die 'SSL_Context->new: '.PublicInbox::TLS::err();
# save ~34K per idle connection (cf. SSL_CTX_set_mode(3ssl))
# RSS goes from 346MB to 171MB with 10K idle NNTPS clients on amd64
# cf. https://rt.cpan.org/Ticket/Display.html?id=129463
my $mode = eval { Net::SSLeay::MODE_RELEASE_BUFFERS() };
if ($mode && $ctx->{context}) {
eval { Net::SSLeay::CTX_set_mode($ctx->{context}, $mode) };
warn "W: $@ (setting SSL_MODE_RELEASE_BUFFERS)\n" if $@;
}
{ SSL_server => 1, SSL_startHandshake => 0, SSL_reuse_ctx => $ctx };
}
sub daemon_prepare ($) {
my ($default_listen) = @_;
my $listener_names = {}; # sockname => IO::Handle
$oldset = PublicInbox::DS::block_signals();
@CMD = ($0, @ARGV);
my ($prog) = ($CMD[0] =~ m!([^/]+)\z!g);
my $help = < \@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,
'cert=s' => \$default_cert,
'key=s' => \$default_key,
'help|h' => \(my $show_help),
);
GetOptions(%opt) or die $help;
if ($show_help) { print $help; exit 0 };
if (defined $pid_file && $pid_file =~ /\.oldbin\z/) {
die "--pid-file cannot end with '.oldbin'\n";
}
@listeners = inherit($listener_names);
# allow socket-activation users to set certs once and not
# have to configure each socket:
my @inherited_names = keys(%$listener_names) if defined($default_cert);
# ignore daemonize when inheriting
$daemonize = undef if scalar @listeners;
push @cfg_listen, $default_listen unless (@listeners || @cfg_listen);
foreach my $l (@cfg_listen) {
my $orig = $l;
my $scheme = '';
if ($l =~ s!\A([^:]+)://!!) {
$scheme = $1;
} elsif ($l =~ /\A(?:\[[^\]]+\]|[^:]+):([0-9])+/) {
my $s = $KNOWN_TLS{$1} // $KNOWN_STARTTLS{$1};
$scheme = $s if defined $s;
}
if ($l =~ s!/?\?(.+)\z!!) {
$tls_opt{"$scheme://$l"} = accept_tls_opt($1);
} elsif (defined($default_cert)) {
$tls_opt{"$scheme://$l"} = accept_tls_opt('');
} elsif ($scheme =~ /\A(?:https|imaps|imaps)\z/) {
die "$orig specified w/o cert=\n";
}
# TODO: use scheme to load either NNTP.pm or HTTP.pm
next if $listener_names->{$l}; # already inherited
my (%o, $sock_pkg);
if (index($l, '/') == 0) {
$sock_pkg = 'IO::Socket::UNIX';
eval "use $sock_pkg";
die $@ if $@;
%o = (Type => SOCK_STREAM, Peer => $l);
if (-S $l) {
my $c = $sock_pkg->new(%o);
if (!defined($c) && $!{ECONNREFUSED}) {
unlink $l or die
"failed to unlink stale socket=$l: $!\n";
} # else: let the bind fail
}
$o{Local} = delete $o{Peer};
} else {
# both work for IPv4, too
for (qw(IO::Socket::IP IO::Socket::INET6)) {
$sock_pkg = $_;
eval "use $sock_pkg";
$@ or last;
}
die $@ if $@;
%o = (LocalAddr => $l, ReuseAddr => 1, Proto => 'tcp');
}
$o{Listen} = 1024;
my $prev = umask 0000;
my $s = eval { $sock_pkg->new(%o) };
warn "error binding $l: $! ($@)\n" unless $s;
umask $prev;
if ($s) {
$listener_names->{sockname($s)} = $s;
$s->blocking(0);
push @listeners, $s;
}
}
# cert/key options in @cfg_listen takes precedence when inheriting,
# but map well-known inherited ports if --listen isn't specified
# at all
for my $sockname (@inherited_names) {
$sockname =~ /:([0-9]+)\z/ or next;
if (my $scheme = $KNOWN_TLS{$1}) {
$tls_opt{"$scheme://$sockname"} ||= accept_tls_opt('');
} elsif (($scheme = $KNOWN_STARTTLS{$1})) {
next if $tls_opt{"$scheme://$sockname"};
$tls_opt{''} ||= accept_tls_opt('');
}
}
die "No listeners bound\n" unless @listeners;
}
sub check_absolute ($$) {
my ($var, $val) = @_;
if (defined $val && index($val, '/') != 0) {
die
"--$var must be an absolute path when using --daemonize: $val\n";
}
}
sub daemonize () {
if ($daemonize) {
require Cwd;
foreach my $i (0..$#ARGV) {
my $arg = $ARGV[$i];
next unless -e $arg;
$ARGV[$i] = Cwd::abs_path($arg);
}
check_absolute('stdout', $stdout);
check_absolute('stderr', $stderr);
check_absolute('pid-file', $pid_file);
chdir '/' or die "chdir failed: $!";
}
if (defined($pid_file) || defined($group) || defined($user)) {
eval { require Net::Server::Daemonize; 1 } // die <&STDIN' or die "redirect stdout failed: $!\n";
open STDERR, '>&STDIN' or die "redirect stderr failed: $!\n";
POSIX::setsid();
$pid = fork // die "fork: $!";
exit if $pid;
}
return unless defined $pid_file;
write_pid($pid_file);
# for ->DESTROY:
bless { pid => $$, pid_file => \$pid_file }, __PACKAGE__;
}
sub worker_quit { # $_[0] = signal name or number (unused)
# killing again terminates immediately:
exit unless @listeners;
$_->close foreach @listeners; # call PublicInbox::DS::close
@listeners = ();
my $proc_name;
my $warn = 0;
# drop idle connections and try to quit gracefully
PublicInbox::DS->SetPostLoopCallback(sub {
my ($dmap, undef) = @_;
my $n = 0;
my $now = now();
for my $s (values %$dmap) {
$s->can('busy') or next;
if ($s->busy) {
++$n;
} else { # close as much as possible, early as possible
$s->close;
}
}
if ($n) {
if (($warn + 5) < now()) {
warn "$$ quitting, $n client(s) left\n";
$warn = now();
}
unless (defined $proc_name) {
$proc_name = (split(/\s+/, $0))[0];
$proc_name =~ s!\A.*?([^/]+)\z!$1!;
}
$0 = "$proc_name quitting, $n client(s) left";
}
$n; # true: loop continues, false: loop breaks
});
}
sub reopen_logs {
if ($stdout) {
open STDOUT, '>>', $stdout or
warn "failed to redirect stdout to $stdout: $!\n";
STDOUT->autoflush(1);
do_chown($stdout);
}
if ($stderr) {
open STDERR, '>>', $stderr or
warn "failed to redirect stderr to $stderr: $!\n";
STDERR->autoflush(1);
do_chown($stderr);
}
}
sub sockname ($) {
my ($s) = @_;
my $addr = getsockname($s) or return;
my ($host, $port) = host_with_port($addr);
if ($port == 0 && $host eq '127.0.0.1') {
my ($path) = Socket::sockaddr_un($addr);
return $path;
}
"$host:$port";
}
sub unpack_ipv6 ($) {
my ($addr) = @_;
my ($port, $host);
# Socket.pm in Perl 5.14+ supports IPv6:
eval {
($port, $host) = Socket::unpack_sockaddr_in6($addr);
$host = Socket::inet_ntop(Socket::AF_INET6(), $host);
};
if ($@) {
# Perl 5.12 or earlier? SpamAssassin and Net::Server use
# Socket6, so it may be installed on our system, already
# (otherwise die here):
require Socket6;
($port, $host) = Socket6::unpack_sockaddr_in6($addr);
$host = Socket6::inet_ntop(Socket6::AF_INET6(), $host);
}
($host, $port);
}
sub host_with_port ($) {
my ($addr) = @_;
my ($port, $host);
# this eval will die on Unix sockets:
eval {
if (length($addr) >= 28) {
($host, $port) = unpack_ipv6($addr);
$host = "[$host]";
} else {
($port, $host) = Socket::sockaddr_in($addr);
$host = Socket::inet_ntoa($host);
}
};
$@ ? ('127.0.0.1', 0) : ($host, $port);
}
sub inherit ($) {
my ($listener_names) = @_;
return () if ($ENV{LISTEN_PID} || 0) != $$;
my $fds = $ENV{LISTEN_FDS} or return ();
my $end = $fds + 2; # LISTEN_FDS_START - 1
my @rv = ();
foreach my $fd (3..$end) {
open(my $s, '<&=', $fd) or warn "fdopen fd=$fd: $!";
if (my $k = sockname($s)) {
my $prev_was_blocking = $s->blocking(0);
warn <<"" if $prev_was_blocking;
Inherited socket (fd=$fd) is blocking, making it non-blocking.
Set 'NonBlocking = true' in the systemd.service unit to avoid stalled
processes when multiple service instances start.
$listener_names->{$k} = $s;
push @rv, $s;
} else {
warn "failed to inherit fd=$fd (LISTEN_FDS=$fds)";
}
}
@rv
}
sub upgrade { # $_[0] = signal name or number (unused)
if ($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($$, $pid_file);
$pid_file .= '.oldbin';
write_pid($pid_file);
}
my $pid = fork;
unless (defined $pid) {
warn "fork failed: $!\n";
return;
}
if ($pid == 0) {
use Fcntl qw(FD_CLOEXEC F_SETFD F_GETFD);
$ENV{LISTEN_FDS} = scalar @listeners;
$ENV{LISTEN_PID} = $$;
foreach my $s (@listeners) {
# @listeners are globs with workers, PI::L w/o workers
$s = $s->{sock} if ref($s) eq 'PublicInbox::Listener';
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 ($sig) = @_;
kill $sig, keys(%pids);
}
sub upgrade_aborted ($) {
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";
unlink_pid_file_safe_ish($$, $pid_file);
$pid_file = $file;
eval { write_pid($pid_file) };
warn $@, "\n" if $@;
}
sub reap_children { # $_[0] = 'CHLD' or POSIX::SIGCHLD()
while (1) {
my $p = waitpid(-1, WNOHANG) or return;
if (defined $reexec_pid && $p == $reexec_pid) {
upgrade_aborted($p);
} elsif (defined(my $id = delete $pids{$p})) {
warn "worker[$id] PID($p) died with: $?\n";
} elsif ($p > 0) {
warn "unknown PID($p) reaped: $?\n";
} else {
return;
}
}
}
sub unlink_pid_file_safe_ish ($$) {
my ($unlink_pid, $file) = @_;
return unless defined $unlink_pid && $unlink_pid == $$;
open my $fh, '<', $file or return;
local $/ = "\n";
defined(my $read_pid = <$fh>) or return;
chomp $read_pid;
if ($read_pid == $unlink_pid) {
Net::Server::Daemonize::unlink_pid_file($file);
}
}
sub master_quit ($) {
exit unless @listeners;
@listeners = ();
kill_workers($_[0]);
}
sub master_loop {
pipe(my ($p0, $p1)) or die "failed to create parent-pipe: $!";
my $set_workers = $worker_processes;
reopen_logs();
my $ignore_winch;
my $sig = {
USR1 => sub { reopen_logs(); kill_workers($_[0]); },
USR2 => \&upgrade,
QUIT => \&master_quit,
INT => \&master_quit,
TERM => \&master_quit,
WINCH => sub {
return if $ignore_winch || !@listeners;
if (-t STDIN || -t STDOUT || -t STDERR) {
$ignore_winch = 1;
warn < sub {
return unless @listeners;
$worker_processes = $set_workers;
kill_workers($_[0]);
},
TTIN => sub {
return unless @listeners;
if ($set_workers > $worker_processes) {
++$worker_processes;
} else {
$worker_processes = ++$set_workers;
}
},
TTOU => sub {
$worker_processes = --$set_workers if $set_workers > 0;
},
CHLD => \&reap_children,
};
my $sigfd = PublicInbox::Sigfd->new($sig);
local @SIG{keys %$sig} = values(%$sig) unless $sigfd;
PublicInbox::DS::sig_setmask($oldset) if !$sigfd;
while (1) { # main loop
my $n = scalar keys %pids;
unless (@listeners) {
exit if $n == 0;
$set_workers = $worker_processes = $n = 0;
}
if ($n > $worker_processes) {
while (my ($k, $v) = each %pids) {
kill('TERM', $k) if $v >= $worker_processes;
}
$n = $worker_processes;
}
my $want = $worker_processes - 1;
if ($n <= $want) {
PublicInbox::DS::block_signals() if !$sigfd;
for my $i ($n..$want) {
my $seed = rand(0xffffffff);
my $pid = fork;
if (!defined $pid) {
warn "failed to fork worker[$i]: $!\n";
} elsif ($pid == 0) {
srand($seed);
eval { Net::SSLeay::randomize() };
$set_user->() if $set_user;
return $p0; # run normal work code
} else {
warn "PID=$pid is worker[$i]\n";
$pids{$pid} = $i;
}
}
PublicInbox::DS::sig_setmask($oldset) if !$sigfd;
}
if ($sigfd) { # Linux and IO::KQueue users:
$sigfd->wait_once;
} else { # wake up every second
sleep(1);
}
}
exit # never gets here, just for documentation
}
sub tls_start_cb ($$) {
my ($opt, $orig_post_accept) = @_;
sub {
my ($io, $addr, $srv) = @_;
my $ssl = IO::Socket::SSL->start_SSL($io, %$opt);
$orig_post_accept->($ssl, $addr, $srv);
}
}
sub defer_accept ($$) {
my ($s, $af_name) = @_;
return unless defined $af_name;
if ($^O eq 'linux') {
my $TCP_DEFER_ACCEPT = 9; # Socket::TCP_DEFER_ACCEPT is in 5.14+
my $x = getsockopt($s, IPPROTO_TCP, $TCP_DEFER_ACCEPT);
return unless defined $x; # may be Unix socket
my $sec = unpack('i', $x);
return if $sec > 0; # systemd users may set a higher value
setsockopt($s, IPPROTO_TCP, $TCP_DEFER_ACCEPT, 1);
} elsif ($^O eq 'freebsd') {
my $x = getsockopt($s, SOL_SOCKET, $SO_ACCEPTFILTER);
return if defined $x; # don't change if set
my $accf_arg = pack('a16a240', $af_name, '');
setsockopt($s, SOL_SOCKET, $SO_ACCEPTFILTER, $accf_arg);
}
}
sub daemon_loop ($$$$) {
my ($refresh, $post_accept, $tlsd, $af_default) = @_;
my %post_accept;
while (my ($k, $v) = each %tls_opt) {
if ($k =~ s!\A(?:https|imaps|nntps)://!!) {
$post_accept{$k} = tls_start_cb($v, $post_accept);
} elsif ($tlsd) { # STARTTLS, $k eq '' is OK
$tlsd->{accept_tls} = $v;
}
}
my $sig = {
HUP => $refresh,
INT => \&worker_quit,
QUIT => \&worker_quit,
TERM => \&worker_quit,
TTIN => 'IGNORE',
TTOU => 'IGNORE',
USR1 => \&reopen_logs,
USR2 => 'IGNORE',
WINCH => 'IGNORE',
CHLD => \&PublicInbox::DS::enqueue_reap,
};
if ($worker_processes > 0) {
$refresh->(); # preload by default
my $fh = master_loop(); # returns if in child process
PublicInbox::EOFpipe->new($fh, \&worker_quit, undef);
} else {
reopen_logs();
$set_user->() if $set_user;
$sig->{USR2} = sub { worker_quit() if upgrade() };
$refresh->();
}
$uid = $gid = undef;
reopen_logs();
@listeners = map {;
my $tls_cb = $post_accept{sockname($_)};
# NNTPS, HTTPS, HTTP, IMAPS and POP3S are client-first traffic
# IMAP, NNTP and POP3 are server-first
defer_accept($_, $tls_cb ? 'dataready' : $af_default);
# this calls epoll_create:
PublicInbox::Listener->new($_, $tls_cb || $post_accept)
} @listeners;
PublicInbox::DS::event_loop($sig, $oldset);
}
sub run ($$$;$) {
my ($default, $refresh, $post_accept, $tlsd) = @_;
daemon_prepare($default);
my $af_default = $default =~ /:8080\z/ ? 'httpready' : undef;
my $for_destroy = daemonize();
# localize GCF2C for tests:
local $PublicInbox::GitAsyncCat::GCF2C;
local $PublicInbox::Git::async_warn = 1;
local $SIG{__WARN__} = PublicInbox::Eml::warn_ignore_cb();
daemon_loop($refresh, $post_accept, $tlsd, $af_default);
PublicInbox::DS->Reset;
# ->DESTROY runs when $for_destroy goes out-of-scope
}
sub do_chown ($) {
my ($path) = @_;
if (defined $uid and !chown($uid, $gid, $path)) {
warn "could not chown $path: $!\n";
}
}
sub write_pid ($) {
my ($path) = @_;
Net::Server::Daemonize::create_pid_file($path);
do_chown($path);
}
sub DESTROY {
unlink_pid_file_safe_ish($_[0]->{pid}, ${$_[0]->{pid_file}});
}
1;