Commit 943df148 authored by Oleg Nesterov's avatar Oleg Nesterov
Browse files

signal: introduce do_sigtimedwait() to factor out compat/native code 



Factor out the common code in sys_rt_sigtimedwait/compat_sys_rt_sigtimedwait
to the new helper, do_sigtimedwait().

Add the comment to document the extra tick we add to timespec_to_jiffies(ts),
thanks to Linus who explained this to me.

Perhaps it would be better to move compat_sys_rt_sigtimedwait() into
signal.c under CONFIG_COMPAT, then we can make do_sigtimedwait() static.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarMatt Fleming <matt.fleming@linux.intel.com>
parent fe0faa00

include/linux/signal.h

+2 −0
Original line number Diff line number Diff line
@@ -242,6 +242,8 @@ extern int __group_send_sig_info(int, struct siginfo *, struct task_struct *); 
extern long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig,

				 siginfo_t *info);

extern long do_sigpending(void __user *, unsigned long);

extern int do_sigtimedwait(const sigset_t *, siginfo_t *,

				const struct timespec *);

extern int sigprocmask(int, sigset_t *, sigset_t *);

extern void set_current_blocked(const sigset_t *);

extern int show_unhandled_signals;

kernel/compat.c

+7 −34
Original line number Diff line number Diff line
@@ -890,10 +890,9 @@ compat_sys_rt_sigtimedwait (compat_sigset_t __user *uthese, 
{

	compat_sigset_t s32;

	sigset_t s;

	int sig;

	struct timespec t;

	siginfo_t info;

	long ret, timeout;

	long ret;



	if (sigsetsize != sizeof(sigset_t))

		return -EINVAL;
@@ -901,45 +900,19 @@ compat_sys_rt_sigtimedwait (compat_sigset_t __user *uthese, 
	if (copy_from_user(&s32, uthese, sizeof(compat_sigset_t)))

		return -EFAULT;

	sigset_from_compat(&s, &s32);

	sigdelsetmask(&s,sigmask(SIGKILL)|sigmask(SIGSTOP));

	signotset(&s);



	timeout = MAX_SCHEDULE_TIMEOUT;

	if (uts) {

		if (get_compat_timespec(&t, uts))

			return -EFAULT;

		if (!timespec_valid(&t))

			return -EINVAL;

		timeout = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec);

	}



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

	sig = dequeue_signal(current, &s, &info);

	if (!sig && timeout) {

		current->real_blocked = current->blocked;

		sigandsets(&current->blocked, &current->blocked, &s);

		recalc_sigpending();

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



		timeout = schedule_timeout_interruptible(timeout);



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

		sig = dequeue_signal(current, &s, &info);

		current->blocked = current->real_blocked;

		siginitset(&current->real_blocked, 0);

		recalc_sigpending();

	}

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

	ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);



	if (sig) {

		ret = sig;

		if (uinfo) {

	if (ret > 0 && uinfo) {

		if (copy_siginfo_to_user32(uinfo, &info))

			ret = -EFAULT;

	}

	} else {

		ret = timeout?-EINTR:-EAGAIN;

	}



	return ret;



}

kernel/signal.c

+65 −45
Original line number Diff line number Diff line
@@ -2503,6 +2503,66 @@ int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) 


#endif



/**

 *  do_sigtimedwait - wait for queued signals specified in @which

 *  @which: queued signals to wait for

 *  @info: if non-null, the signal's siginfo is returned here

 *  @ts: upper bound on process time suspension

 */

int do_sigtimedwait(const sigset_t *which, siginfo_t *info,

			const struct timespec *ts)

{

	struct task_struct *tsk = current;

	long timeout = MAX_SCHEDULE_TIMEOUT;

	sigset_t mask = *which;

	int sig;



	if (ts) {

		if (!timespec_valid(ts))

			return -EINVAL;

		timeout = timespec_to_jiffies(ts);

		/*

		 * We can be close to the next tick, add another one

		 * to ensure we will wait at least the time asked for.

		 */

		if (ts->tv_sec || ts->tv_nsec)

			timeout++;

	}



	/*

	 * Invert the set of allowed signals to get those we want to block.

	 */

	sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));

	signotset(&mask);



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

	sig = dequeue_signal(tsk, &mask, info);

	if (!sig && timeout) {

		/*

		 * None ready, temporarily unblock those we're interested

		 * while we are sleeping in so that we'll be awakened when

		 * they arrive.

		 */

		tsk->real_blocked = tsk->blocked;

		sigandsets(&tsk->blocked, &tsk->blocked, &mask);

		recalc_sigpending();

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



		timeout = schedule_timeout_interruptible(timeout);



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

		sig = dequeue_signal(tsk, &mask, info);

		tsk->blocked = tsk->real_blocked;

		siginitset(&tsk->real_blocked, 0);

		recalc_sigpending();

	}

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



	if (sig)

		return sig;

	return timeout ? -EINTR : -EAGAIN;

}



/**

 *  sys_rt_sigtimedwait - synchronously wait for queued signals specified

 *			in @uthese
@@ -2515,11 +2575,10 @@ SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, 
		siginfo_t __user *, uinfo, const struct timespec __user *, uts,

		size_t, sigsetsize)

{

	int ret, sig;

	sigset_t these;

	struct timespec ts;

	siginfo_t info;

	long timeout;

	int ret;



	/* XXX: Don't preclude handling different sized sigset_t's.  */

	if (sigsetsize != sizeof(sigset_t))
@@ -2528,56 +2587,17 @@ SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, 
	if (copy_from_user(&these, uthese, sizeof(these)))

		return -EFAULT;



	/*

	 * Invert the set of allowed signals to get those we

	 * want to block.

	 */

	sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP));

	signotset(&these);



	timeout = MAX_SCHEDULE_TIMEOUT;

	if (uts) {

		if (copy_from_user(&ts, uts, sizeof(ts)))

			return -EFAULT;

		if (!timespec_valid(&ts))

			return -EINVAL;

		timeout = timespec_to_jiffies(&ts) + (ts.tv_sec || ts.tv_nsec);

	}



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

	sig = dequeue_signal(current, &these, &info);

	if (!sig && timeout) {

		/*

		 * None ready -- temporarily unblock those we're

		 * interested while we are sleeping in so that we'll

		 * be awakened when they arrive.

		 */

		current->real_blocked = current->blocked;

		sigandsets(&current->blocked, &current->blocked, &these);

		recalc_sigpending();

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



		timeout = schedule_timeout_interruptible(timeout);



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

		sig = dequeue_signal(current, &these, &info);

		current->blocked = current->real_blocked;

		siginitset(&current->real_blocked, 0);

		recalc_sigpending();

	}

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

	ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);



	if (sig) {

		ret = sig;

		if (uinfo) {

	if (ret > 0 && uinfo) {

		if (copy_siginfo_to_user(uinfo, &info))

			ret = -EFAULT;

	}

	} else {

		ret = -EAGAIN;

		if (timeout)

			ret = -EINTR;

	}



	return ret;

}

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