Commit fddad75

nsxivfddad75

don't spoil errno in sig handler (#411)

reported by thread-sanitizer.

the sighandler's spoiled `errno` was causing xlib to incorrectly assume some
error occurred and thus causing the crash described in #391.

to reproduce:

* Open an nsxiv window
* Open another terminal and run the following:

	var=$(pidof nsxiv); while :; do kill -s SIGCHLD $var; done

putting the `pid` into a variable is actually important because doing
`$(pidof nsxiv)` inside the loop makes it really hard to reproduce the
issue, I presume because of the extra process invocation it was sending
less SIGCHLD and so putting it into a variable avoids that overhead and
is able to generate more signals.

instead of reaping the zombies manually, we now pass the
`SA_NOCLDSTOP|SA_NOCLDWAIT` for SIGCHLD instead so that the zombies are
reaped automatically.

Author: NRK
Date: 2023-01-26 16:26 +0000
Parent: 75849ad
Commit: fddad757c6d2645ed7b2d8f64931818d5b3b7a00

+5 −10

1 file changed

Browse files Patch

−Context 3+

M main.c +5 −10

M main.c View

		@@ -843,19 +843,14 @@ static void run(void)
843	843		}
844	844		}
845	845
846		−	static void sigchld(int sig)
847		−	{
848		−	while (waitpid(-1, NULL, WNOHANG) > 0);
849		−	}
850		−
851		−	static void setup_signal(int sig, void (*handler)(int sig))
	846	+	static void setup_signal(int sig, void (*handler)(int sig), int flags)
852	847		{
853	848		struct sigaction sa;
854	849
855	850		sa.sa_handler = handler;
856	851		sigemptyset(&sa.sa_mask);
857		−	sa.sa_flags = SA_RESTART \| SA_NOCLDSTOP;
858		−	if (sigaction(sig, &sa, 0) == -1)
	852	+	sa.sa_flags = flags;
	853	+	if (sigaction(sig, &sa, NULL) < 0)
859	854		error(EXIT_FAILURE, errno, "signal %d", sig);
860	855		}
861	856
		@@ -865,8 +860,8 @@ int main(int argc, char *argv[])
865	860		size_t n;
866	861		const char homedir, dsuffix = "";
867	862
868		−	setup_signal(SIGCHLD, sigchld);
869		−	setup_signal(SIGPIPE, SIG_IGN);
	863	+	setup_signal(SIGCHLD, SIG_DFL, SA_RESTART\|SA_NOCLDSTOP\|SA_NOCLDWAIT);
	864	+	setup_signal(SIGPIPE, SIG_IGN, 0);
870	865
871	866		setlocale(LC_COLLATE, "");
872	867

nsxiv/fddad75

don't spoil errno in sig handler (#411)

nsxivfddad75