spawn: pi_fork_exec: restore parent sigmask in child

We continue to unblock SIGCHLD unconditionally, but also
any signals not blocked by the parent (wq_worker).

This will allow Ctrl-C (SIGINT) to stop "git clone" and allow
git-clone cleanup to be performed and other long-running
processes when pi_fork_exec supports setpgid(2).  This won't
affect existing daemons on systems with signalfd(2) or
EVFILT_SIGNAL at all, since those run with signals blocked
anyways.

1 files changed, 2 insertions, 4 deletions

diff --git a/lib/PublicInbox/SpawnPP.pm b/lib/PublicInbox/SpawnPP.pm
index b0ad4da5..f64b95dc 100644
--- a/lib/PublicInbox/SpawnPP.pm
+++ b/lib/PublicInbox/SpawnPP.pm
@@ -37,10 +37,8 @@ sub pi_fork_exec ($$$$$$) {
                         chdir $cd or die "chdir $cd: $!";
                 }
                 $SIG{$_} = 'DEFAULT' for keys %SIG;
-                my $cset = POSIX::SigSet->new();
-                $cset->addset(POSIX::SIGCHLD) or die "can't add SIGCHLD: $!";
-                sigprocmask(SIG_UNBLOCK, $cset) or
-                                        die "can't unblock SIGCHLD: $!";
+                $old->delset(POSIX::SIGCHLD) or die "delset SIGCHLD: $!";
+                sigprocmask(SIG_SETMASK, $old) or die "SETMASK: ~SIGCHLD: $!";
                 if ($ENV{MOD_PERL}) {
                         exec which('env'), '-i', @$env, @$cmd;
                         die "exec env -i ... $cmd->[0] failed: $!\n";