Function execsigs

freebsd/kern/kern_sig.c:981–1033

* Reset signals for an exec of the specified process. */

 * Reset signals for an exec of the specified process.
 */
void
execsigs(struct proc *p)
{
	sigset_t osigignore;
	struct sigacts *ps;
	int sig;
	struct thread *td;

	/*
	 * Reset caught signals.  Held signals remain held
	 * through td_sigmask (unless they were caught,
	 * and are now ignored by default).
	 */
	PROC_LOCK_ASSERT(p, MA_OWNED);
	ps = p->p_sigacts;
	mtx_lock(&ps->ps_mtx);
	sig_drop_caught(p);

	/*
	 * As CloudABI processes cannot modify signal handlers, fully
	 * reset all signals to their default behavior. Do ignore
	 * SIGPIPE, as it would otherwise be impossible to recover from
	 * writes to broken pipes and sockets.
	 */
	if (SV_PROC_ABI(p) == SV_ABI_CLOUDABI) {
		osigignore = ps->ps_sigignore;
		while (SIGNOTEMPTY(osigignore)) {
			sig = sig_ffs(&osigignore);
			SIGDELSET(osigignore, sig);
			if (sig != SIGPIPE)
				sigdflt(ps, sig);
		}
		SIGADDSET(ps->ps_sigignore, SIGPIPE);
	}

	/*
	 * Reset stack state to the user stack.
	 * Clear set of signals caught on the signal stack.
	 */
	td = curthread;
	MPASS(td->td_proc == p);
	td->td_sigstk.ss_flags = SS_DISABLE;
	td->td_sigstk.ss_size = 0;
	td->td_sigstk.ss_sp = 0;
	td->td_pflags &= ~TDP_ALTSTACK;
	/*
	 * Reset no zombies if child dies flag as Solaris does.
	 */
	ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
	if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
		ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
	mtx_unlock(&ps->ps_mtx);
}

/*
 * kern_sigprocmask()