Commit 93585eea authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by Linus Torvalds
Browse files

signals: consolidate checks for whether or not to ignore a signal 

Both sig_ignored() and do_sigaction() check for signr to be explicitly or
implicitly ignored.  Introduce a helper for them.

This patch is aimed to help handling signals by pid namespace's init, and was
derived from one of Oleg's patches
https://lists.linux-foundation.org/pipermail/containers/2007-December/009308.html


so, if he doesn't mind, he should be considered as an author.

Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 06fffb12

kernel/signal.c

+14 −10
Original line number Diff line number Diff line
@@ -39,11 +39,19 @@ 


static struct kmem_cache *sigqueue_cachep;





static int sig_ignored(struct task_struct *t, int sig)

static int __sig_ignored(struct task_struct *t, int sig)

{

	void __user *handler;



	/* Is it explicitly or implicitly ignored? */



	handler = t->sighand->action[sig - 1].sa.sa_handler;

	return handler == SIG_IGN ||

		(handler == SIG_DFL && sig_kernel_ignore(sig));

}



static int sig_ignored(struct task_struct *t, int sig)

{

	/*

	 * Tracers always want to know about signals..

	 */
@@ -58,10 +66,7 @@ static int sig_ignored(struct task_struct *t, int sig) 
	if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))

		return 0;



	/* Is it explicitly or implicitly ignored? */

	handler = t->sighand->action[sig-1].sa.sa_handler;

	return   handler == SIG_IGN ||

		(handler == SIG_DFL && sig_kernel_ignore(sig));

	return __sig_ignored(t, sig);

}



/*
@@ -2331,13 +2336,14 @@ sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo) 


int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)

{

	struct task_struct *t = current;

	struct k_sigaction *k;

	sigset_t mask;



	if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))

		return -EINVAL;



	k = &current->sighand->action[sig-1];

	k = &t->sighand->action[sig-1];



	spin_lock_irq(&current->sighand->siglock);

	if (oact)
@@ -2358,9 +2364,7 @@ int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) 
		 *   (for example, SIGCHLD), shall cause the pending signal to

		 *   be discarded, whether or not it is blocked"

		 */

		if (act->sa.sa_handler == SIG_IGN ||

		   (act->sa.sa_handler == SIG_DFL && sig_kernel_ignore(sig))) {

			struct task_struct *t = current;

		if (__sig_ignored(t, sig)) {

			sigemptyset(&mask);

			sigaddset(&mask, sig);

			rm_from_queue_full(&mask, &t->signal->shared_pending);