Sivecano/dwl - Change EK6VCEIAKFHDTJOI7PEEIUZ2BO5AYS4FFOOYC3UNLZSHLJBD5W3AC

Don't bother with ignoring SIGCHLD

It added complexity, especially with the differences in behavior between handled and ignored signals across an exec().

Created by Devin J. Pohly on June 16, 2023

EK6VCEIAKFHDTJOI7PEEIUZ2BO5AYS4FFOOYC3UNLZSHLJBD5W3AC

Dependencies

In channels

main

Change contents

Insertion in dwl.c at line 300 [8.4]
[6.63]
[7.519]
```
static void sigchld(int unused);
```
Deletion in dwl.c at line 401 [8.4]
B:BD[9.103] → [10.57:90]
```
static void sigchld(int unused);
```

Deletion in dwl.c at line 1966 [8.4]

B:BD[11.32623] → [4.5:67]

			sa.sa_handler = SIG_DFL;
			sigaction(SIGCHLD, &sa, NULL);

Replacement in dwl.c at line 2130 [8.4]

B:BD[11.38419] → [12.138:483]

	struct sigaction sa_term = {.sa_flags = SA_RESTART, .sa_handler = quitsignal};
	struct sigaction sa_sigchld = {
#ifdef XWAYLAND
		.sa_flags = SA_RESTART,
		.sa_handler = sigchld,
#else
		.sa_flags = SA_NOCLDSTOP | SA_NOCLDWAIT | SA_RESTART,
		.sa_handler = SIG_IGN,
#endif
	};
	sigemptyset(&sa_term.sa_mask);
	sigemptyset(&sa_sigchld.sa_mask);

[11.38419]

[11.38489]

	/* Set up signal handlers */
	struct sigaction sa = {.sa_flags = SA_RESTART, .sa_handler = sigchld};
	sigemptyset(&sa.sa_mask);
	sigaction(SIGCHLD, &sa, NULL);
	sa.sa_handler = quitsignal;
	sigaction(SIGINT, &sa, NULL);
	sigaction(SIGTERM, &sa, NULL);

Deletion in dwl.c at line 2142 [8.4]

B:BD[11.38661] → [11.38661:38692]

B:BD[11.38692] → [12.484:597]


	/* Set up signal handlers */
	sigaction(SIGCHLD, &sa_sigchld, NULL);
	sigaction(SIGINT, &sa_term, NULL);
	sigaction(SIGTERM, &sa_term, NULL);

Insertion in dwl.c at line 2317 [8.4]

[11.45859]

sigchld(int unused)
{
#ifdef XWAYLAND
	siginfo_t in;
	/* We should be able to remove this function in favor of a simple
	 *	struct sigaction sa = {.sa_handler = SIG_IGN};
	 * 	sigaction(SIGCHLD, &sa, NULL);
	 * but the Xwayland implementation in wlroots currently prevents us from
	 * setting our own disposition for SIGCHLD.
	 */
	/* WNOWAIT leaves the child in a waitable state, in case this is the
	 * XWayland process
	 */
	while (!waitid(P_ALL, 0, &in, WEXITED|WNOHANG|WNOWAIT) && in.si_pid
			&& (!xwayland || in.si_pid != xwayland->server->pid))
		waitpid(in.si_pid, NULL, 0);
#else
	while (waitpid(-1, NULL, WNOHANG) > 0);
#endif
}
void

Deletion in dwl.c at line 2342 [8.4]

B:BD[11.45903] → [5.5:139]

		struct sigaction sa = {.sa_flags = SA_RESTART, .sa_handler = SIG_DFL};
		sigemptyset(&sa.sa_mask);
		sigaction(SIGCHLD, &sa, NULL);

Deletion in dwl.c at line 2782 [8.4]

B:BD[11.56880] → [11.56880:56992]

B:BD[11.56992] → [3.825:912]

∅:D[12.692] → [11.57026:57150]

∅:D[3.912] → [11.57026:57150]

B:BD[11.57026] → [11.57026:57150]

B:BD[11.57233] → [11.57233:57398]

B:BD[11.57398] → [2.5:62]

∅:D[2.62] → [11.57440:57471]

B:BD[11.57440] → [11.57440:57471]

}
void
sigchld(int unused)
{
	siginfo_t in;
	/* We should be able to remove this function in favor of a simple
	 *	struct sigaction sa = {.sa_handler = SIG_IGN};
	 * 	sigaction(SIGCHLD, &sa, NULL);
	 * but the Xwayland implementation in wlroots currently prevents us from
	 * setting our own disposition for SIGCHLD.
	 */
	/* WNOWAIT leaves the child in a waitable state, in case this is the
	 * XWayland process
	 */
	while (!waitid(P_ALL, 0, &in, WEXITED|WNOHANG|WNOWAIT) && in.si_pid
			&& (!xwayland || in.si_pid != xwayland->server->pid))
		waitpid(in.si_pid, NULL, 0);