From 975dffc9bcb96f10bdc8a70bf6af67c2b46ab4b5 Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Sun, 7 Feb 2021 08:51:43 +0000
Subject: [PATCH] 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.
---
lib/PublicInbox/Spawn.pm | 26 ++++++++++++--------------
lib/PublicInbox/SpawnPP.pm | 6 ++----
2 files changed, 14 insertions(+), 18 deletions(-)
diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm
index f7dcb024..bac24dd1 100644
--- a/lib/PublicInbox/Spawn.pm
+++ b/lib/PublicInbox/Spawn.pm
@@ -82,20 +82,20 @@ int pi_fork_exec(SV *redirref, SV *file, SV *cmdref, SV *envref, SV *rlimref,
const char *filename = SvPV_nolen(file);
pid_t pid;
char **argv, **envp;
- sigset_t set, old, cset;
+ sigset_t set, old;
int ret, perrnum, cerrnum = 0;
+ int chld_is_member;
AV2C_COPY(argv, cmd);
AV2C_COPY(envp, env);
- ret = sigfillset(&set);
- assert(ret == 0 && "BUG calling sigfillset");
- ret = sigprocmask(SIG_SETMASK, &set, &old);
- assert(ret == 0 && "BUG calling sigprocmask to block");
- ret = sigemptyset(&cset);
- assert(ret == 0 && "BUG calling sigemptyset");
- ret = sigaddset(&cset, SIGCHLD);
- assert(ret == 0 && "BUG calling sigaddset for SIGCHLD");
+ if (sigfillset(&set)) return -1;
+ if (sigprocmask(SIG_SETMASK, &set, &old)) return -1;
+ chld_is_member = sigismember(&old, SIGCHLD);
+ if (chld_is_member < 0) return -1;
+ if (chld_is_member > 0)
+ sigdelset(&old, SIGCHLD);
+
pid = vfork();
if (pid == 0) {
int sig;
@@ -127,15 +127,13 @@ int pi_fork_exec(SV *redirref, SV *file, SV *cmdref, SV *envref, SV *rlimref,
exit_err(&cerrnum);
}
- /*
- * don't bother unblocking other signals for now, just SIGCHLD.
- * we don't want signals to the group taking out a subprocess
- */
- (void)sigprocmask(SIG_UNBLOCK, &cset, NULL);
+ (void)sigprocmask(SIG_SETMASK, &old, NULL);
execve(filename, argv, envp);
exit_err(&cerrnum);
}
perrnum = errno;
+ if (chld_is_member > 0)
+ sigaddset(&old, SIGCHLD);
ret = sigprocmask(SIG_SETMASK, &old, NULL);
assert(ret == 0 && "BUG calling sigprocmask to restore");
if (cerrnum) {
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";
--
2.50.0