# Copyright (C) 2015-2018 all contributors
# License: AGPL-3.0+
# contains common daemon code for the nntpd and httpd servers.
# This may be used for read-only IMAP server if we decide to implement it.
package PublicInbox::Daemon;
use strict;
use warnings;
use Getopt::Long qw/:config gnu_getopt no_ignore_case auto_abbrev/;
use IO::Handle;
use IO::Socket;
use Cwd qw/abs_path/;
STDOUT->autoflush(1);
STDERR->autoflush(1);
use PublicInbox::DS qw(now);
require PublicInbox::EvCleanup;
require POSIX;
require PublicInbox::Listener;
require PublicInbox::ParentPipe;
my @CMD;
my $set_user;
my (@cfg_listen, $stdout, $stderr, $group, $user, $pid_file, $daemonize);
my $worker_processes = 1;
my @listeners;
my %pids;
my %listener_names;
my $reexec_pid;
my $cleanup;
my ($uid, $gid);
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
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;
push @listeners, $s;
}
}
die "No listeners bound\n" unless @listeners;
}
sub check_absolute ($$) {
my ($var, $val) = @_;
if (defined $val && index($val, '/') != 0) {
die
"--$var must be an absolute path when using --daemonize: $val\n";
}
}
sub daemonize () {
if ($daemonize) {
foreach my $i (0..$#ARGV) {
my $arg = $ARGV[$i];
next unless -e $arg;
$ARGV[$i] = abs_path($arg);
}
check_absolute('stdout', $stdout);
check_absolute('stderr', $stderr);
check_absolute('pid-file', $pid_file);
chdir '/' or die "chdir failed: $!";
}
return unless (defined $pid_file || defined $group || defined $user
|| $daemonize);
eval { require Net::Server::Daemonize };
if ($@) {
die
"Net::Server required for --pid-file, --group, --user, and --daemonize\n$@\n";
}
Net::Server::Daemonize::check_pid_file($pid_file) if defined $pid_file;
$uid = Net::Server::Daemonize::get_uid($user) if defined $user;
if (defined $group) {
$gid = Net::Server::Daemonize::get_gid($group);
$gid = (split /\s+/, $gid)[0];
} elsif (defined $uid) {
$gid = (getpwuid($uid))[3];
}
# We change users in the worker to ensure upgradability,
# The upgrade will create the ".oldbin" pid file in the
# same directory as the given pid file.
$uid and $set_user = sub {
$set_user = undef;
Net::Server::Daemonize::set_user($uid, $gid);
};
if ($daemonize) {
my $pid = fork;
die "could not fork: $!\n" unless defined $pid;
exit if $pid;
open(STDIN, '+<', '/dev/null') or
die "redirect stdin failed: $!\n";
open STDOUT, '>&STDIN' or die "redirect stdout failed: $!\n";
open STDERR, '>&STDIN' or die "redirect stderr failed: $!\n";
POSIX::setsid();
$pid = fork;
die "could not fork: $!\n" unless defined $pid;
exit if $pid;
}
if (defined $pid_file) {
write_pid($pid_file);
my $unlink_pid = $$;
$cleanup = sub {
$cleanup = undef; # avoid cyclic reference
unlink_pid_file_safe_ish($unlink_pid, $pid_file);
};
}
}
sub worker_quit {
my ($reason) = @_;
# killing again terminates immediately:
exit unless @listeners;
$_->close foreach @listeners; # call PublicInbox::DS::close
@listeners = ();
$reason->close if ref($reason) eq 'PublicInbox::ParentPipe';
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();
foreach my $s (values %$dmap) {
$s->can('busy') or next;
if ($s->busy($now)) {
++$n;
} else {
# close as much as possible, early as possible
$s->close;
}
}
if ($n) {
if (($warn + 5) < now()) {
warn "$$ quitting, $n client(s) left\n";
$warn = now();
}
unless (defined $proc_name) {
$proc_name = (split(/\s+/, $0))[0];
$proc_name =~ s!\A.*?([^/]+)\z!$1!;
}
$0 = "$proc_name quitting, $n client(s) left";
}
$n; # true: loop continues, false: loop breaks
});
}
sub reopen_logs {
if ($stdout) {
open STDOUT, '>>', $stdout or
warn "failed to redirect stdout to $stdout: $!\n";
STDOUT->autoflush(1);
do_chown($stdout);
}
if ($stderr) {
open STDERR, '>>', $stderr or
warn "failed to redirect stderr to $stderr: $!\n";
STDERR->autoflush(1);
do_chown($stderr);
}
}
sub sockname ($) {
my ($s) = @_;
my $addr = getsockname($s) or return;
my ($host, $port) = host_with_port($addr);
if ($port == 0 && $host eq '127.0.0.1') {
my ($path) = Socket::sockaddr_un($addr);
return $path;
}
"$host:$port";
}
sub unpack_ipv6 ($) {
my ($addr) = @_;
my ($port, $host);
# Socket.pm in Perl 5.14+ supports IPv6:
eval {
($port, $host) = Socket::unpack_sockaddr_in6($addr);
$host = Socket::inet_ntop(Socket::AF_INET6(), $host);
};
if ($@) {
# Perl 5.12 or earlier? SpamAssassin and Net::Server use
# Socket6, so it may be installed on our system, already
# (otherwise die here):
require Socket6;
($port, $host) = Socket6::unpack_sockaddr_in6($addr);
$host = Socket6::inet_ntop(Socket6::AF_INET6(), $host);
}
($host, $port);
}
sub host_with_port ($) {
my ($addr) = @_;
my ($port, $host);
# this eval will die on Unix sockets:
eval {
if (length($addr) >= 28) {
($host, $port) = unpack_ipv6($addr);
$host = "[$host]";
} else {
($port, $host) = Socket::sockaddr_in($addr);
$host = Socket::inet_ntoa($host);
}
};
$@ ? ('127.0.0.1', 0) : ($host, $port);
}
sub inherit () {
return () if ($ENV{LISTEN_PID} || 0) != $$;
my $fds = $ENV{LISTEN_FDS} or return ();
my $end = $fds + 2; # LISTEN_FDS_START - 1
my @rv = ();
foreach my $fd (3..$end) {
my $s = IO::Handle->new_from_fd($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($$, $pid_file);
$pid_file .= '.oldbin';
write_pid($pid_file);
}
my $pid = fork;
unless (defined $pid) {
warn "fork failed: $!\n";
return;
}
if ($pid == 0) {
use Fcntl qw(FD_CLOEXEC F_SETFD F_GETFD);
$ENV{LISTEN_FDS} = scalar @listeners;
$ENV{LISTEN_PID} = $$;
foreach my $s (@listeners) {
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, $pid;
}
}
sub upgrade_aborted ($) {
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($$, $pid_file);
$pid_file = $file;
eval { write_pid($pid_file) };
warn $@, "\n" if $@;
}
sub reap_children () {
while (1) {
my $p = waitpid(-1, &POSIX::WNOHANG) or return;
if (defined $reexec_pid && $p == $reexec_pid) {
upgrade_aborted($p);
} elsif (defined(my $id = delete $pids{$p})) {
warn "worker[$id] PID($p) died with: $?\n";
} elsif ($p > 0) {
warn "unknown PID($p) reaped: $?\n";
} else {
return;
}
}
}
sub unlink_pid_file_safe_ish ($$) {
my ($unlink_pid, $file) = @_;
return unless defined $unlink_pid && $unlink_pid == $$;
open my $fh, '<', $file or return;
local $/ = "\n";
defined(my $read_pid = <$fh>) or return;
chomp $read_pid;
if ($read_pid == $unlink_pid) {
Net::Server::Daemonize::unlink_pid_file($file);
}
}
sub master_loop {
pipe(my ($p0, $p1)) or die "failed to create parent-pipe: $!";
pipe(my ($r, $w)) or die "failed to create self-pipe: $!";
if ($^O eq 'linux') { # 1031: F_SETPIPE_SZ = 1031
fcntl($_, 1031, 4096) for ($w, $p1);
}
IO::Handle::blocking($w, 0);
my $set_workers = $worker_processes;
my @caught;
my $master_pid = $$;
foreach my $s (qw(HUP CHLD QUIT INT TERM USR1 USR2 TTIN TTOU WINCH)) {
$SIG{$s} = sub {
return if $$ != $master_pid;
push @caught, $s;
syswrite($w, '.');
};
}
reopen_logs();
# main loop
my $quit = 0;
while (1) {
while (my $s = shift @caught) {
if ($s eq 'USR1') {
reopen_logs();
kill_workers($s);
} elsif ($s eq 'USR2') {
upgrade();
} elsif ($s =~ /\A(?:QUIT|TERM|INT)\z/) {
exit if $quit++;
kill_workers($s);
} elsif ($s eq 'WINCH') {
if (-t STDIN || -t STDOUT || -t STDERR) {
warn
"ignoring SIGWINCH since we are not daemonized\n";
$SIG{WINCH} = 'IGNORE';
} else {
$worker_processes = 0;
}
} elsif ($s eq 'HUP') {
$worker_processes = $set_workers;
kill_workers($s);
} elsif ($s eq 'TTIN') {
if ($set_workers > $worker_processes) {
++$worker_processes;
} else {
$worker_processes = ++$set_workers;
}
} elsif ($s eq 'TTOU') {
if ($set_workers > 0) {
$worker_processes = --$set_workers;
}
} elsif ($s eq 'CHLD') {
reap_children();
}
}
my $n = scalar keys %pids;
if ($quit) {
exit if $n == 0;
$set_workers = $worker_processes = $n = 0;
}
if ($n > $worker_processes) {
while (my ($k, $v) = each %pids) {
kill('TERM', $k) if $v >= $worker_processes;
}
$n = $worker_processes;
}
foreach my $i ($n..($worker_processes - 1)) {
my $pid = fork;
if (!defined $pid) {
warn "failed to fork worker[$i]: $!\n";
} elsif ($pid == 0) {
$set_user->() if $set_user;
return $p0; # run normal work code
} else {
warn "PID=$pid is worker[$i]\n";
$pids{$pid} = $i;
}
}
# just wait on signal events here:
sysread($r, my $buf, 8);
}
exit # never gets here, just for documentation
}
sub daemon_loop ($$) {
my ($refresh, $post_accept) = @_;
PublicInbox::EvCleanup::enable(); # early for $refresh
my $parent_pipe;
if ($worker_processes > 0) {
$refresh->(); # preload by default
my $fh = master_loop(); # returns if in child process
$parent_pipe = PublicInbox::ParentPipe->new($fh, *worker_quit);
} else {
reopen_logs();
$set_user->() if $set_user;
$SIG{USR2} = sub { worker_quit('USR2') if upgrade() };
$refresh->();
}
$uid = $gid = undef;
reopen_logs();
$SIG{QUIT} = $SIG{INT} = $SIG{TERM} = *worker_quit;
$SIG{USR1} = *reopen_logs;
$SIG{HUP} = $refresh;
$SIG{CHLD} = 'DEFAULT';
$SIG{$_} = 'IGNORE' for qw(USR2 TTIN TTOU WINCH);
# this calls epoll_create:
@listeners = map {
PublicInbox::Listener->new($_, $post_accept)
} @listeners;
PublicInbox::DS->EventLoop;
$parent_pipe = undef;
}
sub run ($$$) {
my ($default, $refresh, $post_accept) = @_;
daemon_prepare($default);
daemonize();
daemon_loop($refresh, $post_accept);
}
sub do_chown ($) {
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);
}
1;