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.

diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm
index f7dcb0249cab4b2a936cce5a9e8f16931343c37e..bac24dd1a7c883dd2f4ba94161ce25b884c2acd9 100644 (file)
--- 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 b0ad4da5c6f7ca79467a158249587f21eb61c555..f64b95dcdefc5feb12d17676c04764e9e61c6140 100644 (file)
--- 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";