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signals: introduce kernel_sigaction()

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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: Oleg 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2014-06-06 14:37:00 -07:00 committed by Linus Torvalds
parent 580d34e42a
commit b4e74264eb
2 changed files with 30 additions and 28 deletions
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18
include/linux/signal.h
View File

@ -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,

40
kernel/signal.c
View File

@ -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;
current->sighand->action[sig - 1].sa.sa_handler = action;
if (action == SIG_IGN) {
sigset_t mask;
sigemptyset(&mask);
sigaddset(&mask, sig);
flush_sigqueue_mask(&mask, &current->signal->shared_pending);
flush_sigqueue_mask(&mask, &current->pending);
recalc_sigpending();
}
spin_unlock_irq(&current->sighand->siglock);
}
EXPORT_SYMBOL(allow_signal);
void disallow_signal(int sig)
{
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)
{