lei: use spawn (vfork + execve) for lazy start

This allows us to rely on FD_CLOEXEC being set on pipes
from prove(1), so forgetting `daemon-stop' won't cause
tests to hang.

Unfortunately, daemon tests will be slower with this.

1 files changed, 5 insertions, 7 deletions

diff --git a/lib/PublicInbox/LeiDaemon.pm b/lib/PublicInbox/LeiDaemon.pm
index b4b1ac59..fd4d00d4 100644
--- a/lib/PublicInbox/LeiDaemon.pm
+++ b/lib/PublicInbox/LeiDaemon.pm
@@ -324,29 +324,27 @@ sub accept_dispatch { # Listener {post_accept} callback
 sub noop {}
 
 # lei(1) calls this when it can't connect
-sub lazy_start ($$) {
+sub lazy_start {
         my ($path, $err) = @_;
         if ($err == ECONNREFUSED) {
                 unlink($path) or die "unlink($path): $!";
         } elsif ($err != ENOENT) {
                 die "connect($path): $!";
         }
+        require IO::FDPass;
         my $umask = umask(077) // die("umask(077): $!");
         my $l = IO::Socket::UNIX->new(Local => $path,
                                         Listen => 1024,
                                         Type => SOCK_STREAM) or
                 $err = $!;
         umask($umask) or die("umask(restore): $!");
-        $l or return $err;
+        $l or return die "bind($path): $err";
         my @st = stat($path) or die "stat($path): $!";
         my $dev_ino_expect = pack('dd', $st[0], $st[1]); # dev+ino
         pipe(my ($eof_r, $eof_w)) or die "pipe: $!";
         my $oldset = PublicInbox::Sigfd::block_signals();
         my $pid = fork // die "fork: $!";
-        if ($pid) {
-                PublicInbox::Sigfd::sig_setmask($oldset);
-                return; # client will connect to $path
-        }
+        return if $pid;
         openlog($path, 'pid', 'user');
         local $SIG{__DIE__} = sub {
                 syslog('crit', "@_");
@@ -360,7 +358,7 @@ sub lazy_start ($$) {
         open STDERR, '>&STDIN' or die "redirect stderr failed: $!\n";
         setsid();
         $pid = fork // die "fork: $!";
-        exit if $pid;
+        return if $pid;
         $0 = "lei-daemon $path";
         require PublicInbox::Listener;
         require PublicInbox::EOFpipe;