From 87b61d1daa05bdcf9d810d1655e5abb45456e9a5 Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Fri, 29 Jul 2016 18:58:51 +0000 Subject: daemon: re-enable SIGWINCH without setsid This allows systemd users to use SIGWINCH to temporarily (and gracefully) stop an instance of a service without doing a code reload to bring it back up: # start temporary new service code systemctl start public-inbox-nntpd@2.service # momentarily paralyze original service systemctl kill -s WINCH public-inbox-nntpd@1.service if new_code_at_2_sucks then # restart original workers systemctl kill -s HUP public-inbox-nntpd@1.service else # new is better than old, replace original instance systemctl restart public-inbox-nntpd@1.service fi # cleanup the temporary service systemctl stop public-inbox-nntpd@2.service This partially reverts commit 73d274e83b7d300f31e0cc1ceeacbf73c6c2a1e4 ("daemon: disable SIGWINCH unless explicitly daemonized") --- lib/PublicInbox/Daemon.pm | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'lib/PublicInbox') diff --git a/lib/PublicInbox/Daemon.pm b/lib/PublicInbox/Daemon.pm index 7849f9c0..9125584b 100644 --- a/lib/PublicInbox/Daemon.pm +++ b/lib/PublicInbox/Daemon.pm @@ -112,7 +112,6 @@ sub daemonize () { check_absolute('pid-file', $pid_file); chdir '/' or die "chdir failed: $!"; - open(STDIN, '+<', '/dev/null') or die "redirect stdin failed: $!"; return unless (defined $pid_file || defined $group || defined $user || $daemonize); @@ -145,6 +144,8 @@ sub daemonize () { 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(); @@ -376,12 +377,12 @@ sub master_loop { exit if $quit++; kill_workers($s); } elsif ($s eq 'WINCH') { - if ($daemonize) { - $worker_processes = 0; - } else { + 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; -- cgit v1.2.3-24-ge0c7