daemon: fix various permissions + daemon issues

When using user-switching in a single process, we must be
careful to not inadvertantly create new Msgmap sqlite3 files.
We must also ensure we set proper permissions on any files
we create.

Additionally, our refactoring was broken as we failed to
actually daemonize or preserve the parent FD in a worker
process.

Finally, default to one worker process since our code may
be fatally broken and it's nice to be able to scale to multiple
cores via SIGTTIN if needed.

1 files changed, 34 insertions, 18 deletions

diff --git a/lib/PublicInbox/Daemon.pm b/lib/PublicInbox/Daemon.pm
index 81ff21cd..9e177f2e 100644
--- a/lib/PublicInbox/Daemon.pm
+++ b/lib/PublicInbox/Daemon.pm
@@ -14,12 +14,13 @@ require PublicInbox::Listener;
 my @CMD;
 my $set_user;
 my (@cfg_listen, $stdout, $stderr, $group, $user, $pid_file, $daemonize);
-my $worker_processes = 0;
+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 ($) {
@@ -76,8 +77,7 @@ sub 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;
+        $uid = Net::Server::Daemonize::get_uid($user) if defined $user;
         if (defined $group) {
                 $gid = Net::Server::Daemonize::get_gid($group);
                 $gid = (split /\s+/, $gid)[0];
@@ -105,10 +105,7 @@ sub daemonize () {
                 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: $!\n";
-                }
+                write_pid($pid_file);
                 my $unlink_pid = $$;
                 $cleanup = sub {
                         unlink_pid_file_safe_ish($unlink_pid, $pid_file);
@@ -146,10 +143,14 @@ sub reopen_logs {
         if ($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);
         }
 }
 
@@ -201,7 +202,7 @@ sub upgrade () {
                 }
                 unlink_pid_file_safe_ish($$, $pid_file);
                 $pid_file .= '.oldbin';
-                Net::Server::Daemonize::create_pid_file($pid_file);
+                write_pid($pid_file);
         }
         my ($pid, $err) = do_fork();
         unless (defined $pid) {
@@ -253,7 +254,7 @@ sub upgrade_aborted ($) {
         $file =~ s/\.oldbin\z// or die "BUG: no '.oldbin' suffix in $file\n";
         unlink_pid_file_safe_ish($$, $pid_file);
         $pid_file = $file;
-        eval { Net::Server::Daemonize::create_pid_file($pid_file) };
+        eval { write_pid($pid_file) };
         warn $@, "\n" if $@;
 }
 
@@ -284,10 +285,8 @@ sub unlink_pid_file_safe_ish ($$) {
         }
 }
 
-sub master_loop ($) {
-        my ($refresh) = @_;
+sub master_loop {
         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 = $worker_processes;
@@ -316,7 +315,6 @@ sub master_loop ($) {
                                 $worker_processes = 0;
                         } elsif ($s eq 'HUP') {
                                 $worker_processes = $set_workers;
-                                $refresh->();
                                 kill_workers($s);
                         } elsif ($s eq 'TTIN') {
                                 if ($set_workers > $worker_processes) {
@@ -346,9 +344,7 @@ sub master_loop ($) {
                                 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
+                                return $p0; # run normal work code
                         } else {
                                 warn "PID=$pid is worker[$i]\n";
                                 $pids{$pid} = $i;
@@ -362,27 +358,47 @@ sub master_loop ($) {
 
 sub daemon_loop ($$) {
         my ($refresh, $post_accept) = @_;
-        $refresh->(); # load config before forking to save work
+        my $parent_pipe;
         if ($worker_processes > 0) {
-                master_loop($refresh); # returns if in child process
+                $parent_pipe = master_loop(); # returns if in child process
+                my $fd = fileno($parent_pipe);
+                Danga::Socket->AddOtherFds($fd => sub { kill('TERM', $$) } );
         } else {
+                reopen_logs();
                 $set_user->() if $set_user;
                 $SIG{USR2} = sub { worker_quit() if upgrade() };
         }
+        $uid = $gid = undef;
         reopen_logs();
+        $refresh->();
         $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;
+        $parent_pipe = undef;
 }
 
 
 sub daemon_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;