user/dev discussion of public-inbox itself
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From: Eric Wong <e@80x24.org>
To: meta@public-inbox.org
Subject: [PATCH 04/19] spawn_pp: die more consistently in child
Date: Sun,  7 Feb 2021 08:51:46 +0000	[thread overview]
Message-ID: <20210207085201.13871-5-e@80x24.org> (raw)
In-Reply-To: <20210207085201.13871-1-e@80x24.org>

The default $SIG{__DIE__} inside a forked child doesn't actually
do what we want it to do.  We don't want it to zip up the stack
the parent used, but instead want to exit the child process
after warning.
---
 lib/PublicInbox/SpawnPP.pm | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/lib/PublicInbox/SpawnPP.pm b/lib/PublicInbox/SpawnPP.pm
index 401cb78d..2c5edef6 100644
--- a/lib/PublicInbox/SpawnPP.pm
+++ b/lib/PublicInbox/SpawnPP.pm
@@ -22,15 +22,15 @@ sub pi_fork_exec ($$$$$$$) {
 		$pid = -1;
 	}
 	if ($pid == 0) {
+		$SIG{__DIE__} = sub { warn @_; _exit 1 };
 		for my $child_fd (0..$#$redir) {
 			my $parent_fd = $redir->[$child_fd];
 			next if $parent_fd == $child_fd;
 			dup2($parent_fd, $child_fd) or
-				die "dup2($parent_fd, $child_fd): $!\n";
+				die "dup2($parent_fd, $child_fd): $!";
 		}
 		if ($pgid >= 0 && !defined(setpgid(0, $pgid))) {
-			warn "setpgid: $!";
-			_exit(1);
+			die "setpgid(0, $pgid): $!";
 		}
 		$SIG{$_} = 'DEFAULT' for keys %SIG;
 		if ($cd ne '') {
@@ -39,20 +39,18 @@ sub pi_fork_exec ($$$$$$$) {
 		while (@$rlim) {
 			my ($r, $soft, $hard) = splice(@$rlim, 0, 3);
 			BSD::Resource::setrlimit($r, $soft, $hard) or
-			  warn "failed to set $r=[$soft,$hard]\n";
+				die "setrlimit($r=[$soft,$hard]: $!)";
 		}
 		$old->delset(POSIX::SIGCHLD) or die "delset SIGCHLD: $!";
 		sigprocmask(SIG_SETMASK, $old) or die "SETMASK: ~SIGCHLD: $!";
+		$cmd->[0] = $f;
 		if ($ENV{MOD_PERL}) {
-			exec which('env'), '-i', @$env, @$cmd;
-			die "exec env -i ... $cmd->[0] failed: $!\n";
+			@$cmd = (which('env'), '-i', @$env, @$cmd);
 		} else {
-			local %ENV = map { split(/=/, $_, 2) } @$env;
-			my @cmd = @$cmd;
-			$cmd[0] = $f;
-			exec @cmd;
-			die "exec $cmd->[0] failed: $!\n";
+			%ENV = map { split(/=/, $_, 2) } @$env;
 		}
+		exec @$cmd;
+		die "exec @$cmd failed: $!";
 	}
 	sigprocmask(SIG_SETMASK, $old) or die "can't unblock signals: $!";
 	$! = $syserr;

  parent reply	other threads:[~2021-02-07  8:52 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-07  8:51 [PATCH 00/19] lei import Maildir, remote mboxrd fixes Eric Wong
2021-02-07  8:51 ` [PATCH 01/19] spawn: pi_fork_exec: restore parent sigmask in child Eric Wong
2021-02-07  8:51 ` [PATCH 02/19] spawn: pi_fork_exec: support "pgid" Eric Wong
2021-02-07 23:10   ` dprintf(3) portability? [was [02/19] spawn: pi_fork_exec: support "pgid"] Eric Wong
2021-02-07  8:51 ` [PATCH 03/19] lei add-external: handle interrupts with --mirror Eric Wong
2021-02-07  8:51 ` Eric Wong [this message]
2021-02-07  8:51 ` [PATCH 05/19] ipc: do not die inside wq_worker child process Eric Wong
2021-02-07  8:51 ` [PATCH 06/19] ipc: trim down the Storable checks Eric Wong
2021-02-07  8:51 ` [PATCH 07/19] Makefile.PL: depend on IO::Uncompress::Gunzip Eric Wong
2021-02-07  8:51 ` [PATCH 08/19] xapcmd: avoid potential die surprise in children Eric Wong
2021-02-07  8:51 ` [PATCH 09/19] tests: guard setup_public_inboxes for SQLite and Xapian Eric Wong
2021-02-07  8:51 ` [PATCH 10/19] Revert "ipc: add support for asynchronous callbacks" Eric Wong
2021-02-07  8:51 ` [PATCH 11/19] ipc: wq_do => wq_io_do Eric Wong
2021-02-07  8:51 ` [PATCH 12/19] lei: more consistent IPC exit and error handling Eric Wong
2021-02-07  8:51 ` [PATCH 13/19] lei: remove --mua-cmd alias for --mua Eric Wong
2021-02-07  8:51 ` [PATCH 14/19] lei: replace --thread with --threads Eric Wong
2021-02-07  8:51 ` [PATCH 15/19] lei q: improve remote mboxrd UX Eric Wong
2021-02-07  9:32   ` [PATCH 20/19] lei_xsearch: allow quieting regular mset progress, too Eric Wong
2021-02-07  8:51 ` [PATCH 16/19] lei q: SIGWINCH process group with the terminal Eric Wong
2021-02-07  8:51 ` [PATCH 17/19] lei import: support Maildirs Eric Wong
2021-02-07  8:52 ` [PATCH 18/19] imap: avoid unnecessary on-stack delete Eric Wong
2021-02-07  8:52 ` [PATCH 19/19] httpd/async: " Eric Wong
2021-02-07 10:40 ` [PATCH 21/19] lei q: fix arbitrary --mua command handling Eric Wong

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