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Commit b4e74264 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

signals: introduce kernel_sigaction() 



Now that allow_signal() is really trivial we can unify it with
disallow_signal().  Add the new helper, kernel_sigaction(), and
reimplement allow_signal/disallow_signal as a trivial wrappers.

This saves one EXPORT_SYMBOL() and the new helper can have more users.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 580d34e4

include/linux/signal.h

+16 −2
Original line number Diff line number Diff line
@@ -284,8 +284,22 @@ extern int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, 
extern void signal_setup_done(int failed, struct ksignal *ksig, int stepping);

extern void signal_delivered(int sig, siginfo_t *info, struct k_sigaction *ka, struct pt_regs *regs, int stepping);

extern void exit_signals(struct task_struct *tsk);

extern void allow_signal(int);

extern void disallow_signal(int);

extern void kernel_sigaction(int, __sighandler_t);



static inline void allow_signal(int sig)

{

	/*

	 * Kernel threads handle their own signals. Let the signal code

	 * know it'll be handled, so that they don't get converted to

	 * SIGKILL or just silently dropped.

	 */

	kernel_sigaction(sig, (__force __sighandler_t)2);

}



static inline void disallow_signal(int sig)

{

	kernel_sigaction(sig, SIG_IGN);

}



/*

 * Eventually that'll replace get_signal_to_deliver(); macro for now,

kernel/signal.c

+12 −24
Original line number Diff line number Diff line
@@ -3067,37 +3067,25 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, 
#endif



/*

 * Let kernel threads use this to say that they allow a certain signal.

 * Must not be used if kthread was cloned with CLONE_SIGHAND.

 * For kthreads only, must not be used if cloned with CLONE_SIGHAND

 */

void allow_signal(int sig)

void kernel_sigaction(int sig, __sighandler_t action)

{

	/*

	 * Kernel threads handle their own signals. Let the signal code

	 * know it'll be handled, so that they don't get converted to

	 * SIGKILL or just silently dropped.

	 */

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

	current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;

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

}

EXPORT_SYMBOL(allow_signal);



void disallow_signal(int sig)

{

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

	if (action == SIG_IGN) {

		sigset_t mask;



		sigemptyset(&mask);

		sigaddset(&mask, sig);



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

	current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN;

		flush_sigqueue_mask(&mask, &current->signal->shared_pending);

		flush_sigqueue_mask(&mask, &current->pending);

		recalc_sigpending();

	}

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

}

EXPORT_SYMBOL(disallow_signal);

EXPORT_SYMBOL(kernel_sigaction);



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

{