daemon: drop listeners early in master on graceful shutdown

For users not relying on socket activation via systemd (or
similar), we want to drop listeners ASAP so another process
can bind to their address.  While we're at it, disable
TTIN and HUP handlers since we have no chance of starting
usable workers without listeners.

1 files changed, 13 insertions, 7 deletions

diff --git a/lib/PublicInbox/Daemon.pm b/lib/PublicInbox/Daemon.pm
index 842ff1cc..9db472a1 100644
--- a/lib/PublicInbox/Daemon.pm
+++ b/lib/PublicInbox/Daemon.pm
@@ -462,23 +462,27 @@ sub unlink_pid_file_safe_ish ($$) {
         }
 }
 
+sub master_quit ($) {
+        exit unless @listeners;
+        @listeners = ();
+        kill_workers($_[0]);
+}
+
 sub master_loop {
         pipe(my ($p0, $p1)) or die "failed to create parent-pipe: $!";
         # 1031: F_SETPIPE_SZ, 4096: page size
         fcntl($p1, 1031, 4096) if $^O eq 'linux';
         my $set_workers = $worker_processes;
         reopen_logs();
-        my $quit = 0;
         my $ignore_winch;
-        my $quit_cb = sub { exit if $quit++; kill_workers($_[0]) };
         my $sig = {
                 USR1 => sub { reopen_logs(); kill_workers($_[0]); },
                 USR2 => \&upgrade,
-                QUIT => $quit_cb,
-                INT => $quit_cb,
-                TERM => $quit_cb,
+                QUIT => \&master_quit,
+                INT => \&master_quit,
+                TERM => \&master_quit,
                 WINCH => sub {
-                        return if $ignore_winch;
+                        return if $ignore_winch || !@listeners;
                         if (-t STDIN || -t STDOUT || -t STDERR) {
                                 $ignore_winch = 1;
                                 warn <<EOF;
@@ -489,10 +493,12 @@ EOF
                         }
                 },
                 HUP => sub {
+                        return unless @listeners;
                         $worker_processes = $set_workers;
                         kill_workers($_[0]);
                 },
                 TTIN => sub {
+                        return unless @listeners;
                         if ($set_workers > $worker_processes) {
                                 ++$worker_processes;
                         } else {
@@ -509,7 +515,7 @@ EOF
         sig_setmask($oldset) if !$sigfd;
         while (1) { # main loop
                 my $n = scalar keys %pids;
-                if ($quit) {
+                unless (@listeners) {
                         exit if $n == 0;
                         $set_workers = $worker_processes = $n = 0;
                 }