diff --git a/kernel/signal.c b/kernel/signal.c
new file mode 100644
index 0000000..f00a1d6
--- /dev/null
+++ b/kernel/signal.c
@@ -0,0 +1,2662 @@
+/*
+ *  linux/kernel/signal.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  1997-11-02  Modified for POSIX.1b signals by Richard Henderson
+ *
+ *  2003-06-02  Jim Houston - Concurrent Computer Corp.
+ *		Changes to use preallocated sigqueue structures
+ *		to allow signals to be sent reliably.
+ */
+
+#include <linux/config.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/smp_lock.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/tty.h>
+#include <linux/binfmts.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/ptrace.h>
+#include <linux/posix-timers.h>
+#include <asm/param.h>
+#include <asm/uaccess.h>
+#include <asm/unistd.h>
+#include <asm/siginfo.h>
+
+/*
+ * SLAB caches for signal bits.
+ */
+
+static kmem_cache_t *sigqueue_cachep;
+
+/*
+ * In POSIX a signal is sent either to a specific thread (Linux task)
+ * or to the process as a whole (Linux thread group).  How the signal
+ * is sent determines whether it's to one thread or the whole group,
+ * which determines which signal mask(s) are involved in blocking it
+ * from being delivered until later.  When the signal is delivered,
+ * either it's caught or ignored by a user handler or it has a default
+ * effect that applies to the whole thread group (POSIX process).
+ *
+ * The possible effects an unblocked signal set to SIG_DFL can have are:
+ *   ignore	- Nothing Happens
+ *   terminate	- kill the process, i.e. all threads in the group,
+ * 		  similar to exit_group.  The group leader (only) reports
+ *		  WIFSIGNALED status to its parent.
+ *   coredump	- write a core dump file describing all threads using
+ *		  the same mm and then kill all those threads
+ *   stop 	- stop all the threads in the group, i.e. TASK_STOPPED state
+ *
+ * SIGKILL and SIGSTOP cannot be caught, blocked, or ignored.
+ * Other signals when not blocked and set to SIG_DFL behaves as follows.
+ * The job control signals also have other special effects.
+ *
+ *	+--------------------+------------------+
+ *	|  POSIX signal      |  default action  |
+ *	+--------------------+------------------+
+ *	|  SIGHUP            |  terminate	|
+ *	|  SIGINT            |	terminate	|
+ *	|  SIGQUIT           |	coredump 	|
+ *	|  SIGILL            |	coredump 	|
+ *	|  SIGTRAP           |	coredump 	|
+ *	|  SIGABRT/SIGIOT    |	coredump 	|
+ *	|  SIGBUS            |	coredump 	|
+ *	|  SIGFPE            |	coredump 	|
+ *	|  SIGKILL           |	terminate(+)	|
+ *	|  SIGUSR1           |	terminate	|
+ *	|  SIGSEGV           |	coredump 	|
+ *	|  SIGUSR2           |	terminate	|
+ *	|  SIGPIPE           |	terminate	|
+ *	|  SIGALRM           |	terminate	|
+ *	|  SIGTERM           |	terminate	|
+ *	|  SIGCHLD           |	ignore   	|
+ *	|  SIGCONT           |	ignore(*)	|
+ *	|  SIGSTOP           |	stop(*)(+)  	|
+ *	|  SIGTSTP           |	stop(*)  	|
+ *	|  SIGTTIN           |	stop(*)  	|
+ *	|  SIGTTOU           |	stop(*)  	|
+ *	|  SIGURG            |	ignore   	|
+ *	|  SIGXCPU           |	coredump 	|
+ *	|  SIGXFSZ           |	coredump 	|
+ *	|  SIGVTALRM         |	terminate	|
+ *	|  SIGPROF           |	terminate	|
+ *	|  SIGPOLL/SIGIO     |	terminate	|
+ *	|  SIGSYS/SIGUNUSED  |	coredump 	|
+ *	|  SIGSTKFLT         |	terminate	|
+ *	|  SIGWINCH          |	ignore   	|
+ *	|  SIGPWR            |	terminate	|
+ *	|  SIGRTMIN-SIGRTMAX |	terminate       |
+ *	+--------------------+------------------+
+ *	|  non-POSIX signal  |  default action  |
+ *	+--------------------+------------------+
+ *	|  SIGEMT            |  coredump	|
+ *	+--------------------+------------------+
+ *
+ * (+) For SIGKILL and SIGSTOP the action is "always", not just "default".
+ * (*) Special job control effects:
+ * When SIGCONT is sent, it resumes the process (all threads in the group)
+ * from TASK_STOPPED state and also clears any pending/queued stop signals
+ * (any of those marked with "stop(*)").  This happens regardless of blocking,
+ * catching, or ignoring SIGCONT.  When any stop signal is sent, it clears
+ * any pending/queued SIGCONT signals; this happens regardless of blocking,
+ * catching, or ignored the stop signal, though (except for SIGSTOP) the
+ * default action of stopping the process may happen later or never.
+ */
+
+#ifdef SIGEMT
+#define M_SIGEMT	M(SIGEMT)
+#else
+#define M_SIGEMT	0
+#endif
+
+#if SIGRTMIN > BITS_PER_LONG
+#define M(sig) (1ULL << ((sig)-1))
+#else
+#define M(sig) (1UL << ((sig)-1))
+#endif
+#define T(sig, mask) (M(sig) & (mask))
+
+#define SIG_KERNEL_ONLY_MASK (\
+	M(SIGKILL)   |  M(SIGSTOP)                                   )
+
+#define SIG_KERNEL_STOP_MASK (\
+	M(SIGSTOP)   |  M(SIGTSTP)   |  M(SIGTTIN)   |  M(SIGTTOU)   )
+
+#define SIG_KERNEL_COREDUMP_MASK (\
+        M(SIGQUIT)   |  M(SIGILL)    |  M(SIGTRAP)   |  M(SIGABRT)   | \
+        M(SIGFPE)    |  M(SIGSEGV)   |  M(SIGBUS)    |  M(SIGSYS)    | \
+        M(SIGXCPU)   |  M(SIGXFSZ)   |  M_SIGEMT                     )
+
+#define SIG_KERNEL_IGNORE_MASK (\
+        M(SIGCONT)   |  M(SIGCHLD)   |  M(SIGWINCH)  |  M(SIGURG)    )
+
+#define sig_kernel_only(sig) \
+		(((sig) < SIGRTMIN)  && T(sig, SIG_KERNEL_ONLY_MASK))
+#define sig_kernel_coredump(sig) \
+		(((sig) < SIGRTMIN)  && T(sig, SIG_KERNEL_COREDUMP_MASK))
+#define sig_kernel_ignore(sig) \
+		(((sig) < SIGRTMIN)  && T(sig, SIG_KERNEL_IGNORE_MASK))
+#define sig_kernel_stop(sig) \
+		(((sig) < SIGRTMIN)  && T(sig, SIG_KERNEL_STOP_MASK))
+
+#define sig_user_defined(t, signr) \
+	(((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_DFL) &&	\
+	 ((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_IGN))
+
+#define sig_fatal(t, signr) \
+	(!T(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \
+	 (t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL)
+
+static int sig_ignored(struct task_struct *t, int sig)
+{
+	void __user * handler;
+
+	/*
+	 * Tracers always want to know about signals..
+	 */
+	if (t->ptrace & PT_PTRACED)
+		return 0;
+
+	/*
+	 * Blocked signals are never ignored, since the
+	 * signal handler may change by the time it is
+	 * unblocked.
+	 */
+	if (sigismember(&t->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));
+}
+
+/*
+ * Re-calculate pending state from the set of locally pending
+ * signals, globally pending signals, and blocked signals.
+ */
+static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
+{
+	unsigned long ready;
+	long i;
+
+	switch (_NSIG_WORDS) {
+	default:
+		for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
+			ready |= signal->sig[i] &~ blocked->sig[i];
+		break;
+
+	case 4: ready  = signal->sig[3] &~ blocked->sig[3];
+		ready |= signal->sig[2] &~ blocked->sig[2];
+		ready |= signal->sig[1] &~ blocked->sig[1];
+		ready |= signal->sig[0] &~ blocked->sig[0];
+		break;
+
+	case 2: ready  = signal->sig[1] &~ blocked->sig[1];
+		ready |= signal->sig[0] &~ blocked->sig[0];
+		break;
+
+	case 1: ready  = signal->sig[0] &~ blocked->sig[0];
+	}
+	return ready !=	0;
+}
+
+#define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
+
+fastcall void recalc_sigpending_tsk(struct task_struct *t)
+{
+	if (t->signal->group_stop_count > 0 ||
+	    PENDING(&t->pending, &t->blocked) ||
+	    PENDING(&t->signal->shared_pending, &t->blocked))
+		set_tsk_thread_flag(t, TIF_SIGPENDING);
+	else
+		clear_tsk_thread_flag(t, TIF_SIGPENDING);
+}
+
+void recalc_sigpending(void)
+{
+	recalc_sigpending_tsk(current);
+}
+
+/* Given the mask, find the first available signal that should be serviced. */
+
+static int
+next_signal(struct sigpending *pending, sigset_t *mask)
+{
+	unsigned long i, *s, *m, x;
+	int sig = 0;
+	
+	s = pending->signal.sig;
+	m = mask->sig;
+	switch (_NSIG_WORDS) {
+	default:
+		for (i = 0; i < _NSIG_WORDS; ++i, ++s, ++m)
+			if ((x = *s &~ *m) != 0) {
+				sig = ffz(~x) + i*_NSIG_BPW + 1;
+				break;
+			}
+		break;
+
+	case 2: if ((x = s[0] &~ m[0]) != 0)
+			sig = 1;
+		else if ((x = s[1] &~ m[1]) != 0)
+			sig = _NSIG_BPW + 1;
+		else
+			break;
+		sig += ffz(~x);
+		break;
+
+	case 1: if ((x = *s &~ *m) != 0)
+			sig = ffz(~x) + 1;
+		break;
+	}
+	
+	return sig;
+}
+
+static struct sigqueue *__sigqueue_alloc(struct task_struct *t, unsigned int __nocast flags,
+					 int override_rlimit)
+{
+	struct sigqueue *q = NULL;
+
+	atomic_inc(&t->user->sigpending);
+	if (override_rlimit ||
+	    atomic_read(&t->user->sigpending) <=
+			t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur)
+		q = kmem_cache_alloc(sigqueue_cachep, flags);
+	if (unlikely(q == NULL)) {
+		atomic_dec(&t->user->sigpending);
+	} else {
+		INIT_LIST_HEAD(&q->list);
+		q->flags = 0;
+		q->lock = NULL;
+		q->user = get_uid(t->user);
+	}
+	return(q);
+}
+
+static inline void __sigqueue_free(struct sigqueue *q)
+{
+	if (q->flags & SIGQUEUE_PREALLOC)
+		return;
+	atomic_dec(&q->user->sigpending);
+	free_uid(q->user);
+	kmem_cache_free(sigqueue_cachep, q);
+}
+
+static void flush_sigqueue(struct sigpending *queue)
+{
+	struct sigqueue *q;
+
+	sigemptyset(&queue->signal);
+	while (!list_empty(&queue->list)) {
+		q = list_entry(queue->list.next, struct sigqueue , list);
+		list_del_init(&q->list);
+		__sigqueue_free(q);
+	}
+}
+
+/*
+ * Flush all pending signals for a task.
+ */
+
+void
+flush_signals(struct task_struct *t)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&t->sighand->siglock, flags);
+	clear_tsk_thread_flag(t,TIF_SIGPENDING);
+	flush_sigqueue(&t->pending);
+	flush_sigqueue(&t->signal->shared_pending);
+	spin_unlock_irqrestore(&t->sighand->siglock, flags);
+}
+
+/*
+ * This function expects the tasklist_lock write-locked.
+ */
+void __exit_sighand(struct task_struct *tsk)
+{
+	struct sighand_struct * sighand = tsk->sighand;
+
+	/* Ok, we're done with the signal handlers */
+	tsk->sighand = NULL;
+	if (atomic_dec_and_test(&sighand->count))
+		kmem_cache_free(sighand_cachep, sighand);
+}
+
+void exit_sighand(struct task_struct *tsk)
+{
+	write_lock_irq(&tasklist_lock);
+	__exit_sighand(tsk);
+	write_unlock_irq(&tasklist_lock);
+}
+
+/*
+ * This function expects the tasklist_lock write-locked.
+ */
+void __exit_signal(struct task_struct *tsk)
+{
+	struct signal_struct * sig = tsk->signal;
+	struct sighand_struct * sighand = tsk->sighand;
+
+	if (!sig)
+		BUG();
+	if (!atomic_read(&sig->count))
+		BUG();
+	spin_lock(&sighand->siglock);
+	posix_cpu_timers_exit(tsk);
+	if (atomic_dec_and_test(&sig->count)) {
+		posix_cpu_timers_exit_group(tsk);
+		if (tsk == sig->curr_target)
+			sig->curr_target = next_thread(tsk);
+		tsk->signal = NULL;
+		spin_unlock(&sighand->siglock);
+		flush_sigqueue(&sig->shared_pending);
+	} else {
+		/*
+		 * If there is any task waiting for the group exit
+		 * then notify it:
+		 */
+		if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) {
+			wake_up_process(sig->group_exit_task);
+			sig->group_exit_task = NULL;
+		}
+		if (tsk == sig->curr_target)
+			sig->curr_target = next_thread(tsk);
+		tsk->signal = NULL;
+		/*
+		 * Accumulate here the counters for all threads but the
+		 * group leader as they die, so they can be added into
+		 * the process-wide totals when those are taken.
+		 * The group leader stays around as a zombie as long
+		 * as there are other threads.  When it gets reaped,
+		 * the exit.c code will add its counts into these totals.
+		 * We won't ever get here for the group leader, since it
+		 * will have been the last reference on the signal_struct.
+		 */
+		sig->utime = cputime_add(sig->utime, tsk->utime);
+		sig->stime = cputime_add(sig->stime, tsk->stime);
+		sig->min_flt += tsk->min_flt;
+		sig->maj_flt += tsk->maj_flt;
+		sig->nvcsw += tsk->nvcsw;
+		sig->nivcsw += tsk->nivcsw;
+		sig->sched_time += tsk->sched_time;
+		spin_unlock(&sighand->siglock);
+		sig = NULL;	/* Marker for below.  */
+	}
+	clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
+	flush_sigqueue(&tsk->pending);
+	if (sig) {
+		/*
+		 * We are cleaning up the signal_struct here.  We delayed
+		 * calling exit_itimers until after flush_sigqueue, just in
+		 * case our thread-local pending queue contained a queued
+		 * timer signal that would have been cleared in
+		 * exit_itimers.  When that called sigqueue_free, it would
+		 * attempt to re-take the tasklist_lock and deadlock.  This
+		 * can never happen if we ensure that all queues the
+		 * timer's signal might be queued on have been flushed
+		 * first.  The shared_pending queue, and our own pending
+		 * queue are the only queues the timer could be on, since
+		 * there are no other threads left in the group and timer
+		 * signals are constrained to threads inside the group.
+		 */
+		exit_itimers(sig);
+		exit_thread_group_keys(sig);
+		kmem_cache_free(signal_cachep, sig);
+	}
+}
+
+void exit_signal(struct task_struct *tsk)
+{
+	write_lock_irq(&tasklist_lock);
+	__exit_signal(tsk);
+	write_unlock_irq(&tasklist_lock);
+}
+
+/*
+ * Flush all handlers for a task.
+ */
+
+void
+flush_signal_handlers(struct task_struct *t, int force_default)
+{
+	int i;
+	struct k_sigaction *ka = &t->sighand->action[0];
+	for (i = _NSIG ; i != 0 ; i--) {
+		if (force_default || ka->sa.sa_handler != SIG_IGN)
+			ka->sa.sa_handler = SIG_DFL;
+		ka->sa.sa_flags = 0;
+		sigemptyset(&ka->sa.sa_mask);
+		ka++;
+	}
+}
+
+
+/* Notify the system that a driver wants to block all signals for this
+ * process, and wants to be notified if any signals at all were to be
+ * sent/acted upon.  If the notifier routine returns non-zero, then the
+ * signal will be acted upon after all.  If the notifier routine returns 0,
+ * then then signal will be blocked.  Only one block per process is
+ * allowed.  priv is a pointer to private data that the notifier routine
+ * can use to determine if the signal should be blocked or not.  */
+
+void
+block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&current->sighand->siglock, flags);
+	current->notifier_mask = mask;
+	current->notifier_data = priv;
+	current->notifier = notifier;
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
+}
+
+/* Notify the system that blocking has ended. */
+
+void
+unblock_all_signals(void)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&current->sighand->siglock, flags);
+	current->notifier = NULL;
+	current->notifier_data = NULL;
+	recalc_sigpending();
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
+}
+
+static inline int collect_signal(int sig, struct sigpending *list, siginfo_t *info)
+{
+	struct sigqueue *q, *first = NULL;
+	int still_pending = 0;
+
+	if (unlikely(!sigismember(&list->signal, sig)))
+		return 0;
+
+	/*
+	 * Collect the siginfo appropriate to this signal.  Check if
+	 * there is another siginfo for the same signal.
+	*/
+	list_for_each_entry(q, &list->list, list) {
+		if (q->info.si_signo == sig) {
+			if (first) {
+				still_pending = 1;
+				break;
+			}
+			first = q;
+		}
+	}
+	if (first) {
+		list_del_init(&first->list);
+		copy_siginfo(info, &first->info);
+		__sigqueue_free(first);
+		if (!still_pending)
+			sigdelset(&list->signal, sig);
+	} else {
+
+		/* Ok, it wasn't in the queue.  This must be
+		   a fast-pathed signal or we must have been
+		   out of queue space.  So zero out the info.
+		 */
+		sigdelset(&list->signal, sig);
+		info->si_signo = sig;
+		info->si_errno = 0;
+		info->si_code = 0;
+		info->si_pid = 0;
+		info->si_uid = 0;
+	}
+	return 1;
+}
+
+static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
+			siginfo_t *info)
+{
+	int sig = 0;
+
+	sig = next_signal(pending, mask);
+	if (sig) {
+		if (current->notifier) {
+			if (sigismember(current->notifier_mask, sig)) {
+				if (!(current->notifier)(current->notifier_data)) {
+					clear_thread_flag(TIF_SIGPENDING);
+					return 0;
+				}
+			}
+		}
+
+		if (!collect_signal(sig, pending, info))
+			sig = 0;
+				
+	}
+	recalc_sigpending();
+
+	return sig;
+}
+
+/*
+ * Dequeue a signal and return the element to the caller, which is 
+ * expected to free it.
+ *
+ * All callers have to hold the siglock.
+ */
+int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
+{
+	int signr = __dequeue_signal(&tsk->pending, mask, info);
+	if (!signr)
+		signr = __dequeue_signal(&tsk->signal->shared_pending,
+					 mask, info);
+ 	if (signr && unlikely(sig_kernel_stop(signr))) {
+ 		/*
+ 		 * Set a marker that we have dequeued a stop signal.  Our
+ 		 * caller might release the siglock and then the pending
+ 		 * stop signal it is about to process is no longer in the
+ 		 * pending bitmasks, but must still be cleared by a SIGCONT
+ 		 * (and overruled by a SIGKILL).  So those cases clear this
+ 		 * shared flag after we've set it.  Note that this flag may
+ 		 * remain set after the signal we return is ignored or
+ 		 * handled.  That doesn't matter because its only purpose
+ 		 * is to alert stop-signal processing code when another
+ 		 * processor has come along and cleared the flag.
+ 		 */
+ 		tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
+ 	}
+	if ( signr &&
+	     ((info->si_code & __SI_MASK) == __SI_TIMER) &&
+	     info->si_sys_private){
+		/*
+		 * Release the siglock to ensure proper locking order
+		 * of timer locks outside of siglocks.  Note, we leave
+		 * irqs disabled here, since the posix-timers code is
+		 * about to disable them again anyway.
+		 */
+		spin_unlock(&tsk->sighand->siglock);
+		do_schedule_next_timer(info);
+		spin_lock(&tsk->sighand->siglock);
+	}
+	return signr;
+}
+
+/*
+ * Tell a process that it has a new active signal..
+ *
+ * NOTE! we rely on the previous spin_lock to
+ * lock interrupts for us! We can only be called with
+ * "siglock" held, and the local interrupt must
+ * have been disabled when that got acquired!
+ *
+ * No need to set need_resched since signal event passing
+ * goes through ->blocked
+ */
+void signal_wake_up(struct task_struct *t, int resume)
+{
+	unsigned int mask;
+
+	set_tsk_thread_flag(t, TIF_SIGPENDING);
+
+	/*
+	 * For SIGKILL, we want to wake it up in the stopped/traced case.
+	 * We don't check t->state here because there is a race with it
+	 * executing another processor and just now entering stopped state.
+	 * By using wake_up_state, we ensure the process will wake up and
+	 * handle its death signal.
+	 */
+	mask = TASK_INTERRUPTIBLE;
+	if (resume)
+		mask |= TASK_STOPPED | TASK_TRACED;
+	if (!wake_up_state(t, mask))
+		kick_process(t);
+}
+
+/*
+ * Remove signals in mask from the pending set and queue.
+ * Returns 1 if any signals were found.
+ *
+ * All callers must be holding the siglock.
+ */
+static int rm_from_queue(unsigned long mask, struct sigpending *s)
+{
+	struct sigqueue *q, *n;
+
+	if (!sigtestsetmask(&s->signal, mask))
+		return 0;
+
+	sigdelsetmask(&s->signal, mask);
+	list_for_each_entry_safe(q, n, &s->list, list) {
+		if (q->info.si_signo < SIGRTMIN &&
+		    (mask & sigmask(q->info.si_signo))) {
+			list_del_init(&q->list);
+			__sigqueue_free(q);
+		}
+	}
+	return 1;
+}
+
+/*
+ * Bad permissions for sending the signal
+ */
+static int check_kill_permission(int sig, struct siginfo *info,
+				 struct task_struct *t)
+{
+	int error = -EINVAL;
+	if (sig < 0 || sig > _NSIG)
+		return error;
+	error = -EPERM;
+	if ((!info || ((unsigned long)info != 1 &&
+			(unsigned long)info != 2 && SI_FROMUSER(info)))
+	    && ((sig != SIGCONT) ||
+		(current->signal->session != t->signal->session))
+	    && (current->euid ^ t->suid) && (current->euid ^ t->uid)
+	    && (current->uid ^ t->suid) && (current->uid ^ t->uid)
+	    && !capable(CAP_KILL))
+		return error;
+	return security_task_kill(t, info, sig);
+}
+
+/* forward decl */
+static void do_notify_parent_cldstop(struct task_struct *tsk,
+				     struct task_struct *parent,
+				     int why);
+
+/*
+ * Handle magic process-wide effects of stop/continue signals.
+ * Unlike the signal actions, these happen immediately at signal-generation
+ * time regardless of blocking, ignoring, or handling.  This does the
+ * actual continuing for SIGCONT, but not the actual stopping for stop
+ * signals.  The process stop is done as a signal action for SIG_DFL.
+ */
+static void handle_stop_signal(int sig, struct task_struct *p)
+{
+	struct task_struct *t;
+
+	if (p->flags & SIGNAL_GROUP_EXIT)
+		/*
+		 * The process is in the middle of dying already.
+		 */
+		return;
+
+	if (sig_kernel_stop(sig)) {
+		/*
+		 * This is a stop signal.  Remove SIGCONT from all queues.
+		 */
+		rm_from_queue(sigmask(SIGCONT), &p->signal->shared_pending);
+		t = p;
+		do {
+			rm_from_queue(sigmask(SIGCONT), &t->pending);
+			t = next_thread(t);
+		} while (t != p);
+	} else if (sig == SIGCONT) {
+		/*
+		 * Remove all stop signals from all queues,
+		 * and wake all threads.
+		 */
+		if (unlikely(p->signal->group_stop_count > 0)) {
+			/*
+			 * There was a group stop in progress.  We'll
+			 * pretend it finished before we got here.  We are
+			 * obliged to report it to the parent: if the
+			 * SIGSTOP happened "after" this SIGCONT, then it
+			 * would have cleared this pending SIGCONT.  If it
+			 * happened "before" this SIGCONT, then the parent
+			 * got the SIGCHLD about the stop finishing before
+			 * the continue happened.  We do the notification
+			 * now, and it's as if the stop had finished and
+			 * the SIGCHLD was pending on entry to this kill.
+			 */
+			p->signal->group_stop_count = 0;
+			p->signal->flags = SIGNAL_STOP_CONTINUED;
+			spin_unlock(&p->sighand->siglock);
+			if (p->ptrace & PT_PTRACED)
+				do_notify_parent_cldstop(p, p->parent,
+							 CLD_STOPPED);
+			else
+				do_notify_parent_cldstop(
+					p->group_leader,
+					p->group_leader->real_parent,
+							 CLD_STOPPED);
+			spin_lock(&p->sighand->siglock);
+		}
+		rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending);
+		t = p;
+		do {
+			unsigned int state;
+			rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
+			
+			/*
+			 * If there is a handler for SIGCONT, we must make
+			 * sure that no thread returns to user mode before
+			 * we post the signal, in case it was the only
+			 * thread eligible to run the signal handler--then
+			 * it must not do anything between resuming and
+			 * running the handler.  With the TIF_SIGPENDING
+			 * flag set, the thread will pause and acquire the
+			 * siglock that we hold now and until we've queued
+			 * the pending signal. 
+			 *
+			 * Wake up the stopped thread _after_ setting
+			 * TIF_SIGPENDING
+			 */
+			state = TASK_STOPPED;
+			if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) {
+				set_tsk_thread_flag(t, TIF_SIGPENDING);
+				state |= TASK_INTERRUPTIBLE;
+			}
+			wake_up_state(t, state);
+
+			t = next_thread(t);
+		} while (t != p);
+
+		if (p->signal->flags & SIGNAL_STOP_STOPPED) {
+			/*
+			 * We were in fact stopped, and are now continued.
+			 * Notify the parent with CLD_CONTINUED.
+			 */
+			p->signal->flags = SIGNAL_STOP_CONTINUED;
+			p->signal->group_exit_code = 0;
+			spin_unlock(&p->sighand->siglock);
+			if (p->ptrace & PT_PTRACED)
+				do_notify_parent_cldstop(p, p->parent,
+							 CLD_CONTINUED);
+			else
+				do_notify_parent_cldstop(
+					p->group_leader,
+					p->group_leader->real_parent,
+							 CLD_CONTINUED);
+			spin_lock(&p->sighand->siglock);
+		} else {
+			/*
+			 * We are not stopped, but there could be a stop
+			 * signal in the middle of being processed after
+			 * being removed from the queue.  Clear that too.
+			 */
+			p->signal->flags = 0;
+		}
+	} else if (sig == SIGKILL) {
+		/*
+		 * Make sure that any pending stop signal already dequeued
+		 * is undone by the wakeup for SIGKILL.
+		 */
+		p->signal->flags = 0;
+	}
+}
+
+static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
+			struct sigpending *signals)
+{
+	struct sigqueue * q = NULL;
+	int ret = 0;
+
+	/*
+	 * fast-pathed signals for kernel-internal things like SIGSTOP
+	 * or SIGKILL.
+	 */
+	if ((unsigned long)info == 2)
+		goto out_set;
+
+	/* Real-time signals must be queued if sent by sigqueue, or
+	   some other real-time mechanism.  It is implementation
+	   defined whether kill() does so.  We attempt to do so, on
+	   the principle of least surprise, but since kill is not
+	   allowed to fail with EAGAIN when low on memory we just
+	   make sure at least one signal gets delivered and don't
+	   pass on the info struct.  */
+
+	q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
+					     ((unsigned long) info < 2 ||
+					      info->si_code >= 0)));
+	if (q) {
+		list_add_tail(&q->list, &signals->list);
+		switch ((unsigned long) info) {
+		case 0:
+			q->info.si_signo = sig;
+			q->info.si_errno = 0;
+			q->info.si_code = SI_USER;
+			q->info.si_pid = current->pid;
+			q->info.si_uid = current->uid;
+			break;
+		case 1:
+			q->info.si_signo = sig;
+			q->info.si_errno = 0;
+			q->info.si_code = SI_KERNEL;
+			q->info.si_pid = 0;
+			q->info.si_uid = 0;
+			break;
+		default:
+			copy_siginfo(&q->info, info);
+			break;
+		}
+	} else {
+		if (sig >= SIGRTMIN && info && (unsigned long)info != 1
+		   && info->si_code != SI_USER)
+		/*
+		 * Queue overflow, abort.  We may abort if the signal was rt
+		 * and sent by user using something other than kill().
+		 */
+			return -EAGAIN;
+		if (((unsigned long)info > 1) && (info->si_code == SI_TIMER))
+			/*
+			 * Set up a return to indicate that we dropped 
+			 * the signal.
+			 */
+			ret = info->si_sys_private;
+	}
+
+out_set:
+	sigaddset(&signals->signal, sig);
+	return ret;
+}
+
+#define LEGACY_QUEUE(sigptr, sig) \
+	(((sig) < SIGRTMIN) && sigismember(&(sigptr)->signal, (sig)))
+
+
+static int
+specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
+{
+	int ret = 0;
+
+	if (!irqs_disabled())
+		BUG();
+	assert_spin_locked(&t->sighand->siglock);
+
+	if (((unsigned long)info > 2) && (info->si_code == SI_TIMER))
+		/*
+		 * Set up a return to indicate that we dropped the signal.
+		 */
+		ret = info->si_sys_private;
+
+	/* Short-circuit ignored signals.  */
+	if (sig_ignored(t, sig))
+		goto out;
+
+	/* Support queueing exactly one non-rt signal, so that we
+	   can get more detailed information about the cause of
+	   the signal. */
+	if (LEGACY_QUEUE(&t->pending, sig))
+		goto out;
+
+	ret = send_signal(sig, info, t, &t->pending);
+	if (!ret && !sigismember(&t->blocked, sig))
+		signal_wake_up(t, sig == SIGKILL);
+out:
+	return ret;
+}
+
+/*
+ * Force a signal that the process can't ignore: if necessary
+ * we unblock the signal and change any SIG_IGN to SIG_DFL.
+ */
+
+int
+force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
+{
+	unsigned long int flags;
+	int ret;
+
+	spin_lock_irqsave(&t->sighand->siglock, flags);
+	if (sigismember(&t->blocked, sig) || t->sighand->action[sig-1].sa.sa_handler == SIG_IGN) {
+		t->sighand->action[sig-1].sa.sa_handler = SIG_DFL;
+		sigdelset(&t->blocked, sig);
+		recalc_sigpending_tsk(t);
+	}
+	ret = specific_send_sig_info(sig, info, t);
+	spin_unlock_irqrestore(&t->sighand->siglock, flags);
+
+	return ret;
+}
+
+void
+force_sig_specific(int sig, struct task_struct *t)
+{
+	unsigned long int flags;
+
+	spin_lock_irqsave(&t->sighand->siglock, flags);
+	if (t->sighand->action[sig-1].sa.sa_handler == SIG_IGN)
+		t->sighand->action[sig-1].sa.sa_handler = SIG_DFL;
+	sigdelset(&t->blocked, sig);
+	recalc_sigpending_tsk(t);
+	specific_send_sig_info(sig, (void *)2, t);
+	spin_unlock_irqrestore(&t->sighand->siglock, flags);
+}
+
+/*
+ * Test if P wants to take SIG.  After we've checked all threads with this,
+ * it's equivalent to finding no threads not blocking SIG.  Any threads not
+ * blocking SIG were ruled out because they are not running and already
+ * have pending signals.  Such threads will dequeue from the shared queue
+ * as soon as they're available, so putting the signal on the shared queue
+ * will be equivalent to sending it to one such thread.
+ */
+#define wants_signal(sig, p, mask) 			\
+	(!sigismember(&(p)->blocked, sig)		\
+	 && !((p)->state & mask)			\
+	 && !((p)->flags & PF_EXITING)			\
+	 && (task_curr(p) || !signal_pending(p)))
+
+
+static void
+__group_complete_signal(int sig, struct task_struct *p)
+{
+	unsigned int mask;
+	struct task_struct *t;
+
+	/*
+	 * Don't bother traced and stopped tasks (but
+	 * SIGKILL will punch through that).
+	 */
+	mask = TASK_STOPPED | TASK_TRACED;
+	if (sig == SIGKILL)
+		mask = 0;
+
+	/*
+	 * Now find a thread we can wake up to take the signal off the queue.
+	 *
+	 * If the main thread wants the signal, it gets first crack.
+	 * Probably the least surprising to the average bear.
+	 */
+	if (wants_signal(sig, p, mask))
+		t = p;
+	else if (thread_group_empty(p))
+		/*
+		 * There is just one thread and it does not need to be woken.
+		 * It will dequeue unblocked signals before it runs again.
+		 */
+		return;
+	else {
+		/*
+		 * Otherwise try to find a suitable thread.
+		 */
+		t = p->signal->curr_target;
+		if (t == NULL)
+			/* restart balancing at this thread */
+			t = p->signal->curr_target = p;
+		BUG_ON(t->tgid != p->tgid);
+
+		while (!wants_signal(sig, t, mask)) {
+			t = next_thread(t);
+			if (t == p->signal->curr_target)
+				/*
+				 * No thread needs to be woken.
+				 * Any eligible threads will see
+				 * the signal in the queue soon.
+				 */
+				return;
+		}
+		p->signal->curr_target = t;
+	}
+
+	/*
+	 * Found a killable thread.  If the signal will be fatal,
+	 * then start taking the whole group down immediately.
+	 */
+	if (sig_fatal(p, sig) && !(p->signal->flags & SIGNAL_GROUP_EXIT) &&
+	    !sigismember(&t->real_blocked, sig) &&
+	    (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) {
+		/*
+		 * This signal will be fatal to the whole group.
+		 */
+		if (!sig_kernel_coredump(sig)) {
+			/*
+			 * Start a group exit and wake everybody up.
+			 * This way we don't have other threads
+			 * running and doing things after a slower
+			 * thread has the fatal signal pending.
+			 */
+			p->signal->flags = SIGNAL_GROUP_EXIT;
+			p->signal->group_exit_code = sig;
+			p->signal->group_stop_count = 0;
+			t = p;
+			do {
+				sigaddset(&t->pending.signal, SIGKILL);
+				signal_wake_up(t, 1);
+				t = next_thread(t);
+			} while (t != p);
+			return;
+		}
+
+		/*
+		 * There will be a core dump.  We make all threads other
+		 * than the chosen one go into a group stop so that nothing
+		 * happens until it gets scheduled, takes the signal off
+		 * the shared queue, and does the core dump.  This is a
+		 * little more complicated than strictly necessary, but it
+		 * keeps the signal state that winds up in the core dump
+		 * unchanged from the death state, e.g. which thread had
+		 * the core-dump signal unblocked.
+		 */
+		rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
+		rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending);
+		p->signal->group_stop_count = 0;
+		p->signal->group_exit_task = t;
+		t = p;
+		do {
+			p->signal->group_stop_count++;
+			signal_wake_up(t, 0);
+			t = next_thread(t);
+		} while (t != p);
+		wake_up_process(p->signal->group_exit_task);
+		return;
+	}
+
+	/*
+	 * The signal is already in the shared-pending queue.
+	 * Tell the chosen thread to wake up and dequeue it.
+	 */
+	signal_wake_up(t, sig == SIGKILL);
+	return;
+}
+
+int
+__group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
+{
+	int ret = 0;
+
+	assert_spin_locked(&p->sighand->siglock);
+	handle_stop_signal(sig, p);
+
+	if (((unsigned long)info > 2) && (info->si_code == SI_TIMER))
+		/*
+		 * Set up a return to indicate that we dropped the signal.
+		 */
+		ret = info->si_sys_private;
+
+	/* Short-circuit ignored signals.  */
+	if (sig_ignored(p, sig))
+		return ret;
+
+	if (LEGACY_QUEUE(&p->signal->shared_pending, sig))
+		/* This is a non-RT signal and we already have one queued.  */
+		return ret;
+
+	/*
+	 * Put this signal on the shared-pending queue, or fail with EAGAIN.
+	 * We always use the shared queue for process-wide signals,
+	 * to avoid several races.
+	 */
+	ret = send_signal(sig, info, p, &p->signal->shared_pending);
+	if (unlikely(ret))
+		return ret;
+
+	__group_complete_signal(sig, p);
+	return 0;
+}
+
+/*
+ * Nuke all other threads in the group.
+ */
+void zap_other_threads(struct task_struct *p)
+{
+	struct task_struct *t;
+
+	p->signal->flags = SIGNAL_GROUP_EXIT;
+	p->signal->group_stop_count = 0;
+
+	if (thread_group_empty(p))
+		return;
+
+	for (t = next_thread(p); t != p; t = next_thread(t)) {
+		/*
+		 * Don't bother with already dead threads
+		 */
+		if (t->exit_state)
+			continue;
+
+		/*
+		 * We don't want to notify the parent, since we are
+		 * killed as part of a thread group due to another
+		 * thread doing an execve() or similar. So set the
+		 * exit signal to -1 to allow immediate reaping of
+		 * the process.  But don't detach the thread group
+		 * leader.
+		 */
+		if (t != p->group_leader)
+			t->exit_signal = -1;
+
+		sigaddset(&t->pending.signal, SIGKILL);
+		rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
+		signal_wake_up(t, 1);
+	}
+}
+
+/*
+ * Must be called with the tasklist_lock held for reading!
+ */
+int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
+{
+	unsigned long flags;
+	int ret;
+
+	ret = check_kill_permission(sig, info, p);
+	if (!ret && sig && p->sighand) {
+		spin_lock_irqsave(&p->sighand->siglock, flags);
+		ret = __group_send_sig_info(sig, info, p);
+		spin_unlock_irqrestore(&p->sighand->siglock, flags);
+	}
+
+	return ret;
+}
+
+/*
+ * kill_pg_info() sends a signal to a process group: this is what the tty
+ * control characters do (^C, ^Z etc)
+ */
+
+int __kill_pg_info(int sig, struct siginfo *info, pid_t pgrp)
+{
+	struct task_struct *p = NULL;
+	int retval, success;
+
+	if (pgrp <= 0)
+		return -EINVAL;
+
+	success = 0;
+	retval = -ESRCH;
+	do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
+		int err = group_send_sig_info(sig, info, p);
+		success |= !err;
+		retval = err;
+	} while_each_task_pid(pgrp, PIDTYPE_PGID, p);
+	return success ? 0 : retval;
+}
+
+int
+kill_pg_info(int sig, struct siginfo *info, pid_t pgrp)
+{
+	int retval;
+
+	read_lock(&tasklist_lock);
+	retval = __kill_pg_info(sig, info, pgrp);
+	read_unlock(&tasklist_lock);
+
+	return retval;
+}
+
+int
+kill_proc_info(int sig, struct siginfo *info, pid_t pid)
+{
+	int error;
+	struct task_struct *p;
+
+	read_lock(&tasklist_lock);
+	p = find_task_by_pid(pid);
+	error = -ESRCH;
+	if (p)
+		error = group_send_sig_info(sig, info, p);
+	read_unlock(&tasklist_lock);
+	return error;
+}
+
+
+/*
+ * kill_something_info() interprets pid in interesting ways just like kill(2).
+ *
+ * POSIX specifies that kill(-1,sig) is unspecified, but what we have
+ * is probably wrong.  Should make it like BSD or SYSV.
+ */
+
+static int kill_something_info(int sig, struct siginfo *info, int pid)
+{
+	if (!pid) {
+		return kill_pg_info(sig, info, process_group(current));
+	} else if (pid == -1) {
+		int retval = 0, count = 0;
+		struct task_struct * p;
+
+		read_lock(&tasklist_lock);
+		for_each_process(p) {
+			if (p->pid > 1 && p->tgid != current->tgid) {
+				int err = group_send_sig_info(sig, info, p);
+				++count;
+				if (err != -EPERM)
+					retval = err;
+			}
+		}
+		read_unlock(&tasklist_lock);
+		return count ? retval : -ESRCH;
+	} else if (pid < 0) {
+		return kill_pg_info(sig, info, -pid);
+	} else {
+		return kill_proc_info(sig, info, pid);
+	}
+}
+
+/*
+ * These are for backward compatibility with the rest of the kernel source.
+ */
+
+/*
+ * These two are the most common entry points.  They send a signal
+ * just to the specific thread.
+ */
+int
+send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
+{
+	int ret;
+	unsigned long flags;
+
+	/*
+	 * Make sure legacy kernel users don't send in bad values
+	 * (normal paths check this in check_kill_permission).
+	 */
+	if (sig < 0 || sig > _NSIG)
+		return -EINVAL;
+
+	/*
+	 * We need the tasklist lock even for the specific
+	 * thread case (when we don't need to follow the group
+	 * lists) in order to avoid races with "p->sighand"
+	 * going away or changing from under us.
+	 */
+	read_lock(&tasklist_lock);  
+	spin_lock_irqsave(&p->sighand->siglock, flags);
+	ret = specific_send_sig_info(sig, info, p);
+	spin_unlock_irqrestore(&p->sighand->siglock, flags);
+	read_unlock(&tasklist_lock);
+	return ret;
+}
+
+int
+send_sig(int sig, struct task_struct *p, int priv)
+{
+	return send_sig_info(sig, (void*)(long)(priv != 0), p);
+}
+
+/*
+ * This is the entry point for "process-wide" signals.
+ * They will go to an appropriate thread in the thread group.
+ */
+int
+send_group_sig_info(int sig, struct siginfo *info, struct task_struct *p)
+{
+	int ret;
+	read_lock(&tasklist_lock);
+	ret = group_send_sig_info(sig, info, p);
+	read_unlock(&tasklist_lock);
+	return ret;
+}
+
+void
+force_sig(int sig, struct task_struct *p)
+{
+	force_sig_info(sig, (void*)1L, p);
+}
+
+/*
+ * When things go south during signal handling, we
+ * will force a SIGSEGV. And if the signal that caused
+ * the problem was already a SIGSEGV, we'll want to
+ * make sure we don't even try to deliver the signal..
+ */
+int
+force_sigsegv(int sig, struct task_struct *p)
+{
+	if (sig == SIGSEGV) {
+		unsigned long flags;
+		spin_lock_irqsave(&p->sighand->siglock, flags);
+		p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
+		spin_unlock_irqrestore(&p->sighand->siglock, flags);
+	}
+	force_sig(SIGSEGV, p);
+	return 0;
+}
+
+int
+kill_pg(pid_t pgrp, int sig, int priv)
+{
+	return kill_pg_info(sig, (void *)(long)(priv != 0), pgrp);
+}
+
+int
+kill_proc(pid_t pid, int sig, int priv)
+{
+	return kill_proc_info(sig, (void *)(long)(priv != 0), pid);
+}
+
+/*
+ * These functions support sending signals using preallocated sigqueue
+ * structures.  This is needed "because realtime applications cannot
+ * afford to lose notifications of asynchronous events, like timer
+ * expirations or I/O completions".  In the case of Posix Timers 
+ * we allocate the sigqueue structure from the timer_create.  If this
+ * allocation fails we are able to report the failure to the application
+ * with an EAGAIN error.
+ */
+ 
+struct sigqueue *sigqueue_alloc(void)
+{
+	struct sigqueue *q;
+
+	if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0)))
+		q->flags |= SIGQUEUE_PREALLOC;
+	return(q);
+}
+
+void sigqueue_free(struct sigqueue *q)
+{
+	unsigned long flags;
+	BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
+	/*
+	 * If the signal is still pending remove it from the
+	 * pending queue.
+	 */
+	if (unlikely(!list_empty(&q->list))) {
+		read_lock(&tasklist_lock);  
+		spin_lock_irqsave(q->lock, flags);
+		if (!list_empty(&q->list))
+			list_del_init(&q->list);
+		spin_unlock_irqrestore(q->lock, flags);
+		read_unlock(&tasklist_lock);
+	}
+	q->flags &= ~SIGQUEUE_PREALLOC;
+	__sigqueue_free(q);
+}
+
+int
+send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)
+{
+	unsigned long flags;
+	int ret = 0;
+
+	/*
+	 * We need the tasklist lock even for the specific
+	 * thread case (when we don't need to follow the group
+	 * lists) in order to avoid races with "p->sighand"
+	 * going away or changing from under us.
+	 */
+	BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
+	read_lock(&tasklist_lock);  
+	spin_lock_irqsave(&p->sighand->siglock, flags);
+	
+	if (unlikely(!list_empty(&q->list))) {
+		/*
+		 * If an SI_TIMER entry is already queue just increment
+		 * the overrun count.
+		 */
+		if (q->info.si_code != SI_TIMER)
+			BUG();
+		q->info.si_overrun++;
+		goto out;
+	} 
+	/* Short-circuit ignored signals.  */
+	if (sig_ignored(p, sig)) {
+		ret = 1;
+		goto out;
+	}
+
+	q->lock = &p->sighand->siglock;
+	list_add_tail(&q->list, &p->pending.list);
+	sigaddset(&p->pending.signal, sig);
+	if (!sigismember(&p->blocked, sig))
+		signal_wake_up(p, sig == SIGKILL);
+
+out:
+	spin_unlock_irqrestore(&p->sighand->siglock, flags);
+	read_unlock(&tasklist_lock);
+	return(ret);
+}
+
+int
+send_group_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)
+{
+	unsigned long flags;
+	int ret = 0;
+
+	BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
+	read_lock(&tasklist_lock);
+	spin_lock_irqsave(&p->sighand->siglock, flags);
+	handle_stop_signal(sig, p);
+
+	/* Short-circuit ignored signals.  */
+	if (sig_ignored(p, sig)) {
+		ret = 1;
+		goto out;
+	}
+
+	if (unlikely(!list_empty(&q->list))) {
+		/*
+		 * If an SI_TIMER entry is already queue just increment
+		 * the overrun count.  Other uses should not try to
+		 * send the signal multiple times.
+		 */
+		if (q->info.si_code != SI_TIMER)
+			BUG();
+		q->info.si_overrun++;
+		goto out;
+	} 
+
+	/*
+	 * Put this signal on the shared-pending queue.
+	 * We always use the shared queue for process-wide signals,
+	 * to avoid several races.
+	 */
+	q->lock = &p->sighand->siglock;
+	list_add_tail(&q->list, &p->signal->shared_pending.list);
+	sigaddset(&p->signal->shared_pending.signal, sig);
+
+	__group_complete_signal(sig, p);
+out:
+	spin_unlock_irqrestore(&p->sighand->siglock, flags);
+	read_unlock(&tasklist_lock);
+	return(ret);
+}
+
+/*
+ * Wake up any threads in the parent blocked in wait* syscalls.
+ */
+static inline void __wake_up_parent(struct task_struct *p,
+				    struct task_struct *parent)
+{
+	wake_up_interruptible_sync(&parent->signal->wait_chldexit);
+}
+
+/*
+ * Let a parent know about the death of a child.
+ * For a stopped/continued status change, use do_notify_parent_cldstop instead.
+ */
+
+void do_notify_parent(struct task_struct *tsk, int sig)
+{
+	struct siginfo info;
+	unsigned long flags;
+	struct sighand_struct *psig;
+
+	BUG_ON(sig == -1);
+
+ 	/* do_notify_parent_cldstop should have been called instead.  */
+ 	BUG_ON(tsk->state & (TASK_STOPPED|TASK_TRACED));
+
+	BUG_ON(!tsk->ptrace &&
+	       (tsk->group_leader != tsk || !thread_group_empty(tsk)));
+
+	info.si_signo = sig;
+	info.si_errno = 0;
+	info.si_pid = tsk->pid;
+	info.si_uid = tsk->uid;
+
+	/* FIXME: find out whether or not this is supposed to be c*time. */
+	info.si_utime = cputime_to_jiffies(cputime_add(tsk->utime,
+						       tsk->signal->utime));
+	info.si_stime = cputime_to_jiffies(cputime_add(tsk->stime,
+						       tsk->signal->stime));
+
+	info.si_status = tsk->exit_code & 0x7f;
+	if (tsk->exit_code & 0x80)
+		info.si_code = CLD_DUMPED;
+	else if (tsk->exit_code & 0x7f)
+		info.si_code = CLD_KILLED;
+	else {
+		info.si_code = CLD_EXITED;
+		info.si_status = tsk->exit_code >> 8;
+	}
+
+	psig = tsk->parent->sighand;
+	spin_lock_irqsave(&psig->siglock, flags);
+	if (sig == SIGCHLD &&
+	    (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
+	     (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
+		/*
+		 * We are exiting and our parent doesn't care.  POSIX.1
+		 * defines special semantics for setting SIGCHLD to SIG_IGN
+		 * or setting the SA_NOCLDWAIT flag: we should be reaped
+		 * automatically and not left for our parent's wait4 call.
+		 * Rather than having the parent do it as a magic kind of
+		 * signal handler, we just set this to tell do_exit that we
+		 * can be cleaned up without becoming a zombie.  Note that
+		 * we still call __wake_up_parent in this case, because a
+		 * blocked sys_wait4 might now return -ECHILD.
+		 *
+		 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
+		 * is implementation-defined: we do (if you don't want
+		 * it, just use SIG_IGN instead).
+		 */
+		tsk->exit_signal = -1;
+		if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
+			sig = 0;
+	}
+	if (sig > 0 && sig <= _NSIG)
+		__group_send_sig_info(sig, &info, tsk->parent);
+	__wake_up_parent(tsk, tsk->parent);
+	spin_unlock_irqrestore(&psig->siglock, flags);
+}
+
+static void
+do_notify_parent_cldstop(struct task_struct *tsk, struct task_struct *parent,
+			 int why)
+{
+	struct siginfo info;
+	unsigned long flags;
+	struct sighand_struct *sighand;
+
+	info.si_signo = SIGCHLD;
+	info.si_errno = 0;
+	info.si_pid = tsk->pid;
+	info.si_uid = tsk->uid;
+
+	/* FIXME: find out whether or not this is supposed to be c*time. */
+	info.si_utime = cputime_to_jiffies(tsk->utime);
+	info.si_stime = cputime_to_jiffies(tsk->stime);
+
+ 	info.si_code = why;
+ 	switch (why) {
+ 	case CLD_CONTINUED:
+ 		info.si_status = SIGCONT;
+ 		break;
+ 	case CLD_STOPPED:
+ 		info.si_status = tsk->signal->group_exit_code & 0x7f;
+ 		break;
+ 	case CLD_TRAPPED:
+ 		info.si_status = tsk->exit_code & 0x7f;
+ 		break;
+ 	default:
+ 		BUG();
+ 	}
+
+	sighand = parent->sighand;
+	spin_lock_irqsave(&sighand->siglock, flags);
+	if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
+	    !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
+		__group_send_sig_info(SIGCHLD, &info, parent);
+	/*
+	 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
+	 */
+	__wake_up_parent(tsk, parent);
+	spin_unlock_irqrestore(&sighand->siglock, flags);
+}
+
+/*
+ * This must be called with current->sighand->siglock held.
+ *
+ * This should be the path for all ptrace stops.
+ * We always set current->last_siginfo while stopped here.
+ * That makes it a way to test a stopped process for
+ * being ptrace-stopped vs being job-control-stopped.
+ *
+ * If we actually decide not to stop at all because the tracer is gone,
+ * we leave nostop_code in current->exit_code.
+ */
+static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info)
+{
+	/*
+	 * If there is a group stop in progress,
+	 * we must participate in the bookkeeping.
+	 */
+	if (current->signal->group_stop_count > 0)
+		--current->signal->group_stop_count;
+
+	current->last_siginfo = info;
+	current->exit_code = exit_code;
+
+	/* Let the debugger run.  */
+	set_current_state(TASK_TRACED);
+	spin_unlock_irq(&current->sighand->siglock);
+	read_lock(&tasklist_lock);
+	if (likely(current->ptrace & PT_PTRACED) &&
+	    likely(current->parent != current->real_parent ||
+		   !(current->ptrace & PT_ATTACHED)) &&
+	    (likely(current->parent->signal != current->signal) ||
+	     !unlikely(current->signal->flags & SIGNAL_GROUP_EXIT))) {
+		do_notify_parent_cldstop(current, current->parent,
+					 CLD_TRAPPED);
+		read_unlock(&tasklist_lock);
+		schedule();
+	} else {
+		/*
+		 * By the time we got the lock, our tracer went away.
+		 * Don't stop here.
+		 */
+		read_unlock(&tasklist_lock);
+		set_current_state(TASK_RUNNING);
+		current->exit_code = nostop_code;
+	}
+
+	/*
+	 * We are back.  Now reacquire the siglock before touching
+	 * last_siginfo, so that we are sure to have synchronized with
+	 * any signal-sending on another CPU that wants to examine it.
+	 */
+	spin_lock_irq(&current->sighand->siglock);
+	current->last_siginfo = NULL;
+
+	/*
+	 * Queued signals ignored us while we were stopped for tracing.
+	 * So check for any that we should take before resuming user mode.
+	 */
+	recalc_sigpending();
+}
+
+void ptrace_notify(int exit_code)
+{
+	siginfo_t info;
+
+	BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
+
+	memset(&info, 0, sizeof info);
+	info.si_signo = SIGTRAP;
+	info.si_code = exit_code;
+	info.si_pid = current->pid;
+	info.si_uid = current->uid;
+
+	/* Let the debugger run.  */
+	spin_lock_irq(&current->sighand->siglock);
+	ptrace_stop(exit_code, 0, &info);
+	spin_unlock_irq(&current->sighand->siglock);
+}
+
+#ifndef HAVE_ARCH_GET_SIGNAL_TO_DELIVER
+
+static void
+finish_stop(int stop_count)
+{
+	/*
+	 * If there are no other threads in the group, or if there is
+	 * a group stop in progress and we are the last to stop,
+	 * report to the parent.  When ptraced, every thread reports itself.
+	 */
+	if (stop_count < 0 || (current->ptrace & PT_PTRACED)) {
+		read_lock(&tasklist_lock);
+		do_notify_parent_cldstop(current, current->parent,
+					 CLD_STOPPED);
+		read_unlock(&tasklist_lock);
+	}
+	else if (stop_count == 0) {
+		read_lock(&tasklist_lock);
+		do_notify_parent_cldstop(current->group_leader,
+					 current->group_leader->real_parent,
+					 CLD_STOPPED);
+		read_unlock(&tasklist_lock);
+	}
+
+	schedule();
+	/*
+	 * Now we don't run again until continued.
+	 */
+	current->exit_code = 0;
+}
+
+/*
+ * This performs the stopping for SIGSTOP and other stop signals.
+ * We have to stop all threads in the thread group.
+ * Returns nonzero if we've actually stopped and released the siglock.
+ * Returns zero if we didn't stop and still hold the siglock.
+ */
+static int
+do_signal_stop(int signr)
+{
+	struct signal_struct *sig = current->signal;
+	struct sighand_struct *sighand = current->sighand;
+	int stop_count = -1;
+
+	if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED))
+		return 0;
+
+	if (sig->group_stop_count > 0) {
+		/*
+		 * There is a group stop in progress.  We don't need to
+		 * start another one.
+		 */
+		signr = sig->group_exit_code;
+		stop_count = --sig->group_stop_count;
+		current->exit_code = signr;
+		set_current_state(TASK_STOPPED);
+		if (stop_count == 0)
+			sig->flags = SIGNAL_STOP_STOPPED;
+		spin_unlock_irq(&sighand->siglock);
+	}
+	else if (thread_group_empty(current)) {
+		/*
+		 * Lock must be held through transition to stopped state.
+		 */
+		current->exit_code = current->signal->group_exit_code = signr;
+		set_current_state(TASK_STOPPED);
+		sig->flags = SIGNAL_STOP_STOPPED;
+		spin_unlock_irq(&sighand->siglock);
+	}
+	else {
+		/*
+		 * There is no group stop already in progress.
+		 * We must initiate one now, but that requires
+		 * dropping siglock to get both the tasklist lock
+		 * and siglock again in the proper order.  Note that
+		 * this allows an intervening SIGCONT to be posted.
+		 * We need to check for that and bail out if necessary.
+		 */
+		struct task_struct *t;
+
+		spin_unlock_irq(&sighand->siglock);
+
+		/* signals can be posted during this window */
+
+		read_lock(&tasklist_lock);
+		spin_lock_irq(&sighand->siglock);
+
+		if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED)) {
+			/*
+			 * Another stop or continue happened while we
+			 * didn't have the lock.  We can just swallow this
+			 * signal now.  If we raced with a SIGCONT, that
+			 * should have just cleared it now.  If we raced
+			 * with another processor delivering a stop signal,
+			 * then the SIGCONT that wakes us up should clear it.
+			 */
+			read_unlock(&tasklist_lock);
+			return 0;
+		}
+
+		if (sig->group_stop_count == 0) {
+			sig->group_exit_code = signr;
+			stop_count = 0;
+			for (t = next_thread(current); t != current;
+			     t = next_thread(t))
+				/*
+				 * Setting state to TASK_STOPPED for a group
+				 * stop is always done with the siglock held,
+				 * so this check has no races.
+				 */
+				if (t->state < TASK_STOPPED) {
+					stop_count++;
+					signal_wake_up(t, 0);
+				}
+			sig->group_stop_count = stop_count;
+		}
+		else {
+			/* A race with another thread while unlocked.  */
+			signr = sig->group_exit_code;
+			stop_count = --sig->group_stop_count;
+		}
+
+		current->exit_code = signr;
+		set_current_state(TASK_STOPPED);
+		if (stop_count == 0)
+			sig->flags = SIGNAL_STOP_STOPPED;
+
+		spin_unlock_irq(&sighand->siglock);
+		read_unlock(&tasklist_lock);
+	}
+
+	finish_stop(stop_count);
+	return 1;
+}
+
+/*
+ * Do appropriate magic when group_stop_count > 0.
+ * We return nonzero if we stopped, after releasing the siglock.
+ * We return zero if we still hold the siglock and should look
+ * for another signal without checking group_stop_count again.
+ */
+static inline int handle_group_stop(void)
+{
+	int stop_count;
+
+	if (current->signal->group_exit_task == current) {
+		/*
+		 * Group stop is so we can do a core dump,
+		 * We are the initiating thread, so get on with it.
+		 */
+		current->signal->group_exit_task = NULL;
+		return 0;
+	}
+
+	if (current->signal->flags & SIGNAL_GROUP_EXIT)
+		/*
+		 * Group stop is so another thread can do a core dump,
+		 * or else we are racing against a death signal.
+		 * Just punt the stop so we can get the next signal.
+		 */
+		return 0;
+
+	/*
+	 * There is a group stop in progress.  We stop
+	 * without any associated signal being in our queue.
+	 */
+	stop_count = --current->signal->group_stop_count;
+	if (stop_count == 0)
+		current->signal->flags = SIGNAL_STOP_STOPPED;
+	current->exit_code = current->signal->group_exit_code;
+	set_current_state(TASK_STOPPED);
+	spin_unlock_irq(&current->sighand->siglock);
+	finish_stop(stop_count);
+	return 1;
+}
+
+int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
+			  struct pt_regs *regs, void *cookie)
+{
+	sigset_t *mask = &current->blocked;
+	int signr = 0;
+
+relock:
+	spin_lock_irq(&current->sighand->siglock);
+	for (;;) {
+		struct k_sigaction *ka;
+
+		if (unlikely(current->signal->group_stop_count > 0) &&
+		    handle_group_stop())
+			goto relock;
+
+		signr = dequeue_signal(current, mask, info);
+
+		if (!signr)
+			break; /* will return 0 */
+
+		if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) {
+			ptrace_signal_deliver(regs, cookie);
+
+			/* Let the debugger run.  */
+			ptrace_stop(signr, signr, info);
+
+			/* We're back.  Did the debugger cancel the sig?  */
+			signr = current->exit_code;
+			if (signr == 0)
+				continue;
+
+			current->exit_code = 0;
+
+			/* Update the siginfo structure if the signal has
+			   changed.  If the debugger wanted something
+			   specific in the siginfo structure then it should
+			   have updated *info via PTRACE_SETSIGINFO.  */
+			if (signr != info->si_signo) {
+				info->si_signo = signr;
+				info->si_errno = 0;
+				info->si_code = SI_USER;
+				info->si_pid = current->parent->pid;
+				info->si_uid = current->parent->uid;
+			}
+
+			/* If the (new) signal is now blocked, requeue it.  */
+			if (sigismember(&current->blocked, signr)) {
+				specific_send_sig_info(signr, info, current);
+				continue;
+			}
+		}
+
+		ka = &current->sighand->action[signr-1];
+		if (ka->sa.sa_handler == SIG_IGN) /* Do nothing.  */
+			continue;
+		if (ka->sa.sa_handler != SIG_DFL) {
+			/* Run the handler.  */
+			*return_ka = *ka;
+
+			if (ka->sa.sa_flags & SA_ONESHOT)
+				ka->sa.sa_handler = SIG_DFL;
+
+			break; /* will return non-zero "signr" value */
+		}
+
+		/*
+		 * Now we are doing the default action for this signal.
+		 */
+		if (sig_kernel_ignore(signr)) /* Default is nothing. */
+			continue;
+
+		/* Init gets no signals it doesn't want.  */
+		if (current->pid == 1)
+			continue;
+
+		if (sig_kernel_stop(signr)) {
+			/*
+			 * The default action is to stop all threads in
+			 * the thread group.  The job control signals
+			 * do nothing in an orphaned pgrp, but SIGSTOP
+			 * always works.  Note that siglock needs to be
+			 * dropped during the call to is_orphaned_pgrp()
+			 * because of lock ordering with tasklist_lock.
+			 * This allows an intervening SIGCONT to be posted.
+			 * We need to check for that and bail out if necessary.
+			 */
+			if (signr != SIGSTOP) {
+				spin_unlock_irq(&current->sighand->siglock);
+
+				/* signals can be posted during this window */
+
+				if (is_orphaned_pgrp(process_group(current)))
+					goto relock;
+
+				spin_lock_irq(&current->sighand->siglock);
+			}
+
+			if (likely(do_signal_stop(signr))) {
+				/* It released the siglock.  */
+				goto relock;
+			}
+
+			/*
+			 * We didn't actually stop, due to a race
+			 * with SIGCONT or something like that.
+			 */
+			continue;
+		}
+
+		spin_unlock_irq(&current->sighand->siglock);
+
+		/*
+		 * Anything else is fatal, maybe with a core dump.
+		 */
+		current->flags |= PF_SIGNALED;
+		if (sig_kernel_coredump(signr)) {
+			/*
+			 * If it was able to dump core, this kills all
+			 * other threads in the group and synchronizes with
+			 * their demise.  If we lost the race with another
+			 * thread getting here, it set group_exit_code
+			 * first and our do_group_exit call below will use
+			 * that value and ignore the one we pass it.
+			 */
+			do_coredump((long)signr, signr, regs);
+		}
+
+		/*
+		 * Death signals, no core dump.
+		 */
+		do_group_exit(signr);
+		/* NOTREACHED */
+	}
+	spin_unlock_irq(&current->sighand->siglock);
+	return signr;
+}
+
+#endif
+
+EXPORT_SYMBOL(recalc_sigpending);
+EXPORT_SYMBOL_GPL(dequeue_signal);
+EXPORT_SYMBOL(flush_signals);
+EXPORT_SYMBOL(force_sig);
+EXPORT_SYMBOL(kill_pg);
+EXPORT_SYMBOL(kill_proc);
+EXPORT_SYMBOL(ptrace_notify);
+EXPORT_SYMBOL(send_sig);
+EXPORT_SYMBOL(send_sig_info);
+EXPORT_SYMBOL(sigprocmask);
+EXPORT_SYMBOL(block_all_signals);
+EXPORT_SYMBOL(unblock_all_signals);
+
+
+/*
+ * System call entry points.
+ */
+
+asmlinkage long sys_restart_syscall(void)
+{
+	struct restart_block *restart = &current_thread_info()->restart_block;
+	return restart->fn(restart);
+}
+
+long do_no_restart_syscall(struct restart_block *param)
+{
+	return -EINTR;
+}
+
+/*
+ * We don't need to get the kernel lock - this is all local to this
+ * particular thread.. (and that's good, because this is _heavily_
+ * used by various programs)
+ */
+
+/*
+ * This is also useful for kernel threads that want to temporarily
+ * (or permanently) block certain signals.
+ *
+ * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
+ * interface happily blocks "unblockable" signals like SIGKILL
+ * and friends.
+ */
+int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
+{
+	int error;
+	sigset_t old_block;
+
+	spin_lock_irq(&current->sighand->siglock);
+	old_block = current->blocked;
+	error = 0;
+	switch (how) {
+	case SIG_BLOCK:
+		sigorsets(&current->blocked, &current->blocked, set);
+		break;
+	case SIG_UNBLOCK:
+		signandsets(&current->blocked, &current->blocked, set);
+		break;
+	case SIG_SETMASK:
+		current->blocked = *set;
+		break;
+	default:
+		error = -EINVAL;
+	}
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+	if (oldset)
+		*oldset = old_block;
+	return error;
+}
+
+asmlinkage long
+sys_rt_sigprocmask(int how, sigset_t __user *set, sigset_t __user *oset, size_t sigsetsize)
+{
+	int error = -EINVAL;
+	sigset_t old_set, new_set;
+
+	/* XXX: Don't preclude handling different sized sigset_t's.  */
+	if (sigsetsize != sizeof(sigset_t))
+		goto out;
+
+	if (set) {
+		error = -EFAULT;
+		if (copy_from_user(&new_set, set, sizeof(*set)))
+			goto out;
+		sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
+
+		error = sigprocmask(how, &new_set, &old_set);
+		if (error)
+			goto out;
+		if (oset)
+			goto set_old;
+	} else if (oset) {
+		spin_lock_irq(&current->sighand->siglock);
+		old_set = current->blocked;
+		spin_unlock_irq(&current->sighand->siglock);
+
+	set_old:
+		error = -EFAULT;
+		if (copy_to_user(oset, &old_set, sizeof(*oset)))
+			goto out;
+	}
+	error = 0;
+out:
+	return error;
+}
+
+long do_sigpending(void __user *set, unsigned long sigsetsize)
+{
+	long error = -EINVAL;
+	sigset_t pending;
+
+	if (sigsetsize > sizeof(sigset_t))
+		goto out;
+
+	spin_lock_irq(&current->sighand->siglock);
+	sigorsets(&pending, &current->pending.signal,
+		  &current->signal->shared_pending.signal);
+	spin_unlock_irq(&current->sighand->siglock);
+
+	/* Outside the lock because only this thread touches it.  */
+	sigandsets(&pending, &current->blocked, &pending);
+
+	error = -EFAULT;
+	if (!copy_to_user(set, &pending, sigsetsize))
+		error = 0;
+
+out:
+	return error;
+}	
+
+asmlinkage long
+sys_rt_sigpending(sigset_t __user *set, size_t sigsetsize)
+{
+	return do_sigpending(set, sigsetsize);
+}
+
+#ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
+
+int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from)
+{
+	int err;
+
+	if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
+		return -EFAULT;
+	if (from->si_code < 0)
+		return __copy_to_user(to, from, sizeof(siginfo_t))
+			? -EFAULT : 0;
+	/*
+	 * If you change siginfo_t structure, please be sure
+	 * this code is fixed accordingly.
+	 * It should never copy any pad contained in the structure
+	 * to avoid security leaks, but must copy the generic
+	 * 3 ints plus the relevant union member.
+	 */
+	err = __put_user(from->si_signo, &to->si_signo);
+	err |= __put_user(from->si_errno, &to->si_errno);
+	err |= __put_user((short)from->si_code, &to->si_code);
+	switch (from->si_code & __SI_MASK) {
+	case __SI_KILL:
+		err |= __put_user(from->si_pid, &to->si_pid);
+		err |= __put_user(from->si_uid, &to->si_uid);
+		break;
+	case __SI_TIMER:
+		 err |= __put_user(from->si_tid, &to->si_tid);
+		 err |= __put_user(from->si_overrun, &to->si_overrun);
+		 err |= __put_user(from->si_ptr, &to->si_ptr);
+		break;
+	case __SI_POLL:
+		err |= __put_user(from->si_band, &to->si_band);
+		err |= __put_user(from->si_fd, &to->si_fd);
+		break;
+	case __SI_FAULT:
+		err |= __put_user(from->si_addr, &to->si_addr);
+#ifdef __ARCH_SI_TRAPNO
+		err |= __put_user(from->si_trapno, &to->si_trapno);
+#endif
+		break;
+	case __SI_CHLD:
+		err |= __put_user(from->si_pid, &to->si_pid);
+		err |= __put_user(from->si_uid, &to->si_uid);
+		err |= __put_user(from->si_status, &to->si_status);
+		err |= __put_user(from->si_utime, &to->si_utime);
+		err |= __put_user(from->si_stime, &to->si_stime);
+		break;
+	case __SI_RT: /* This is not generated by the kernel as of now. */
+	case __SI_MESGQ: /* But this is */
+		err |= __put_user(from->si_pid, &to->si_pid);
+		err |= __put_user(from->si_uid, &to->si_uid);
+		err |= __put_user(from->si_ptr, &to->si_ptr);
+		break;
+	default: /* this is just in case for now ... */
+		err |= __put_user(from->si_pid, &to->si_pid);
+		err |= __put_user(from->si_uid, &to->si_uid);
+		break;
+	}
+	return err;
+}
+
+#endif
+
+asmlinkage long
+sys_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 = 0;
+
+	/* XXX: Don't preclude handling different sized sigset_t's.  */
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+
+	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);
+
+	if (uts) {
+		if (copy_from_user(&ts, uts, sizeof(ts)))
+			return -EFAULT;
+		if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0
+		    || ts.tv_sec < 0)
+			return -EINVAL;
+	}
+
+	spin_lock_irq(&current->sighand->siglock);
+	sig = dequeue_signal(current, &these, &info);
+	if (!sig) {
+		timeout = MAX_SCHEDULE_TIMEOUT;
+		if (uts)
+			timeout = (timespec_to_jiffies(&ts)
+				   + (ts.tv_sec || ts.tv_nsec));
+
+		if (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);
+
+			current->state = TASK_INTERRUPTIBLE;
+			timeout = schedule_timeout(timeout);
+
+			if (current->flags & PF_FREEZE)
+				refrigerator(PF_FREEZE);
+			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);
+
+	if (sig) {
+		ret = sig;
+		if (uinfo) {
+			if (copy_siginfo_to_user(uinfo, &info))
+				ret = -EFAULT;
+		}
+	} else {
+		ret = -EAGAIN;
+		if (timeout)
+			ret = -EINTR;
+	}
+
+	return ret;
+}
+
+asmlinkage long
+sys_kill(int pid, int sig)
+{
+	struct siginfo info;
+
+	info.si_signo = sig;
+	info.si_errno = 0;
+	info.si_code = SI_USER;
+	info.si_pid = current->tgid;
+	info.si_uid = current->uid;
+
+	return kill_something_info(sig, &info, pid);
+}
+
+/**
+ *  sys_tgkill - send signal to one specific thread
+ *  @tgid: the thread group ID of the thread
+ *  @pid: the PID of the thread
+ *  @sig: signal to be sent
+ *
+ *  This syscall also checks the tgid and returns -ESRCH even if the PID
+ *  exists but it's not belonging to the target process anymore. This
+ *  method solves the problem of threads exiting and PIDs getting reused.
+ */
+asmlinkage long sys_tgkill(int tgid, int pid, int sig)
+{
+	struct siginfo info;
+	int error;
+	struct task_struct *p;
+
+	/* This is only valid for single tasks */
+	if (pid <= 0 || tgid <= 0)
+		return -EINVAL;
+
+	info.si_signo = sig;
+	info.si_errno = 0;
+	info.si_code = SI_TKILL;
+	info.si_pid = current->tgid;
+	info.si_uid = current->uid;
+
+	read_lock(&tasklist_lock);
+	p = find_task_by_pid(pid);
+	error = -ESRCH;
+	if (p && (p->tgid == tgid)) {
+		error = check_kill_permission(sig, &info, p);
+		/*
+		 * The null signal is a permissions and process existence
+		 * probe.  No signal is actually delivered.
+		 */
+		if (!error && sig && p->sighand) {
+			spin_lock_irq(&p->sighand->siglock);
+			handle_stop_signal(sig, p);
+			error = specific_send_sig_info(sig, &info, p);
+			spin_unlock_irq(&p->sighand->siglock);
+		}
+	}
+	read_unlock(&tasklist_lock);
+	return error;
+}
+
+/*
+ *  Send a signal to only one task, even if it's a CLONE_THREAD task.
+ */
+asmlinkage long
+sys_tkill(int pid, int sig)
+{
+	struct siginfo info;
+	int error;
+	struct task_struct *p;
+
+	/* This is only valid for single tasks */
+	if (pid <= 0)
+		return -EINVAL;
+
+	info.si_signo = sig;
+	info.si_errno = 0;
+	info.si_code = SI_TKILL;
+	info.si_pid = current->tgid;
+	info.si_uid = current->uid;
+
+	read_lock(&tasklist_lock);
+	p = find_task_by_pid(pid);
+	error = -ESRCH;
+	if (p) {
+		error = check_kill_permission(sig, &info, p);
+		/*
+		 * The null signal is a permissions and process existence
+		 * probe.  No signal is actually delivered.
+		 */
+		if (!error && sig && p->sighand) {
+			spin_lock_irq(&p->sighand->siglock);
+			handle_stop_signal(sig, p);
+			error = specific_send_sig_info(sig, &info, p);
+			spin_unlock_irq(&p->sighand->siglock);
+		}
+	}
+	read_unlock(&tasklist_lock);
+	return error;
+}
+
+asmlinkage long
+sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo)
+{
+	siginfo_t info;
+
+	if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
+		return -EFAULT;
+
+	/* Not even root can pretend to send signals from the kernel.
+	   Nor can they impersonate a kill(), which adds source info.  */
+	if (info.si_code >= 0)
+		return -EPERM;
+	info.si_signo = sig;
+
+	/* POSIX.1b doesn't mention process groups.  */
+	return kill_proc_info(sig, &info, pid);
+}
+
+int
+do_sigaction(int sig, const struct k_sigaction *act, struct k_sigaction *oact)
+{
+	struct k_sigaction *k;
+
+	if (sig < 1 || sig > _NSIG || (act && sig_kernel_only(sig)))
+		return -EINVAL;
+
+	k = &current->sighand->action[sig-1];
+
+	spin_lock_irq(&current->sighand->siglock);
+	if (signal_pending(current)) {
+		/*
+		 * If there might be a fatal signal pending on multiple
+		 * threads, make sure we take it before changing the action.
+		 */
+		spin_unlock_irq(&current->sighand->siglock);
+		return -ERESTARTNOINTR;
+	}
+
+	if (oact)
+		*oact = *k;
+
+	if (act) {
+		/*
+		 * POSIX 3.3.1.3:
+		 *  "Setting a signal action to SIG_IGN for a signal that is
+		 *   pending shall cause the pending signal to be discarded,
+		 *   whether or not it is blocked."
+		 *
+		 *  "Setting a signal action to SIG_DFL for a signal that is
+		 *   pending and whose default action is to ignore the signal
+		 *   (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))) {
+			/*
+			 * This is a fairly rare case, so we only take the
+			 * tasklist_lock once we're sure we'll need it.
+			 * Now we must do this little unlock and relock
+			 * dance to maintain the lock hierarchy.
+			 */
+			struct task_struct *t = current;
+			spin_unlock_irq(&t->sighand->siglock);
+			read_lock(&tasklist_lock);
+			spin_lock_irq(&t->sighand->siglock);
+			*k = *act;
+			sigdelsetmask(&k->sa.sa_mask,
+				      sigmask(SIGKILL) | sigmask(SIGSTOP));
+			rm_from_queue(sigmask(sig), &t->signal->shared_pending);
+			do {
+				rm_from_queue(sigmask(sig), &t->pending);
+				recalc_sigpending_tsk(t);
+				t = next_thread(t);
+			} while (t != current);
+			spin_unlock_irq(&current->sighand->siglock);
+			read_unlock(&tasklist_lock);
+			return 0;
+		}
+
+		*k = *act;
+		sigdelsetmask(&k->sa.sa_mask,
+			      sigmask(SIGKILL) | sigmask(SIGSTOP));
+	}
+
+	spin_unlock_irq(&current->sighand->siglock);
+	return 0;
+}
+
+int 
+do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp)
+{
+	stack_t oss;
+	int error;
+
+	if (uoss) {
+		oss.ss_sp = (void __user *) current->sas_ss_sp;
+		oss.ss_size = current->sas_ss_size;
+		oss.ss_flags = sas_ss_flags(sp);
+	}
+
+	if (uss) {
+		void __user *ss_sp;
+		size_t ss_size;
+		int ss_flags;
+
+		error = -EFAULT;
+		if (!access_ok(VERIFY_READ, uss, sizeof(*uss))
+		    || __get_user(ss_sp, &uss->ss_sp)
+		    || __get_user(ss_flags, &uss->ss_flags)
+		    || __get_user(ss_size, &uss->ss_size))
+			goto out;
+
+		error = -EPERM;
+		if (on_sig_stack(sp))
+			goto out;
+
+		error = -EINVAL;
+		/*
+		 *
+		 * Note - this code used to test ss_flags incorrectly
+		 *  	  old code may have been written using ss_flags==0
+		 *	  to mean ss_flags==SS_ONSTACK (as this was the only
+		 *	  way that worked) - this fix preserves that older
+		 *	  mechanism
+		 */
+		if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
+			goto out;
+
+		if (ss_flags == SS_DISABLE) {
+			ss_size = 0;
+			ss_sp = NULL;
+		} else {
+			error = -ENOMEM;
+			if (ss_size < MINSIGSTKSZ)
+				goto out;
+		}
+
+		current->sas_ss_sp = (unsigned long) ss_sp;
+		current->sas_ss_size = ss_size;
+	}
+
+	if (uoss) {
+		error = -EFAULT;
+		if (copy_to_user(uoss, &oss, sizeof(oss)))
+			goto out;
+	}
+
+	error = 0;
+out:
+	return error;
+}
+
+#ifdef __ARCH_WANT_SYS_SIGPENDING
+
+asmlinkage long
+sys_sigpending(old_sigset_t __user *set)
+{
+	return do_sigpending(set, sizeof(*set));
+}
+
+#endif
+
+#ifdef __ARCH_WANT_SYS_SIGPROCMASK
+/* Some platforms have their own version with special arguments others
+   support only sys_rt_sigprocmask.  */
+
+asmlinkage long
+sys_sigprocmask(int how, old_sigset_t __user *set, old_sigset_t __user *oset)
+{
+	int error;
+	old_sigset_t old_set, new_set;
+
+	if (set) {
+		error = -EFAULT;
+		if (copy_from_user(&new_set, set, sizeof(*set)))
+			goto out;
+		new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
+
+		spin_lock_irq(&current->sighand->siglock);
+		old_set = current->blocked.sig[0];
+
+		error = 0;
+		switch (how) {
+		default:
+			error = -EINVAL;
+			break;
+		case SIG_BLOCK:
+			sigaddsetmask(&current->blocked, new_set);
+			break;
+		case SIG_UNBLOCK:
+			sigdelsetmask(&current->blocked, new_set);
+			break;
+		case SIG_SETMASK:
+			current->blocked.sig[0] = new_set;
+			break;
+		}
+
+		recalc_sigpending();
+		spin_unlock_irq(&current->sighand->siglock);
+		if (error)
+			goto out;
+		if (oset)
+			goto set_old;
+	} else if (oset) {
+		old_set = current->blocked.sig[0];
+	set_old:
+		error = -EFAULT;
+		if (copy_to_user(oset, &old_set, sizeof(*oset)))
+			goto out;
+	}
+	error = 0;
+out:
+	return error;
+}
+#endif /* __ARCH_WANT_SYS_SIGPROCMASK */
+
+#ifdef __ARCH_WANT_SYS_RT_SIGACTION
+asmlinkage long
+sys_rt_sigaction(int sig,
+		 const struct sigaction __user *act,
+		 struct sigaction __user *oact,
+		 size_t sigsetsize)
+{
+	struct k_sigaction new_sa, old_sa;
+	int ret = -EINVAL;
+
+	/* XXX: Don't preclude handling different sized sigset_t's.  */
+	if (sigsetsize != sizeof(sigset_t))
+		goto out;
+
+	if (act) {
+		if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
+			return -EFAULT;
+	}
+
+	ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
+
+	if (!ret && oact) {
+		if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
+			return -EFAULT;
+	}
+out:
+	return ret;
+}
+#endif /* __ARCH_WANT_SYS_RT_SIGACTION */
+
+#ifdef __ARCH_WANT_SYS_SGETMASK
+
+/*
+ * For backwards compatibility.  Functionality superseded by sigprocmask.
+ */
+asmlinkage long
+sys_sgetmask(void)
+{
+	/* SMP safe */
+	return current->blocked.sig[0];
+}
+
+asmlinkage long
+sys_ssetmask(int newmask)
+{
+	int old;
+
+	spin_lock_irq(&current->sighand->siglock);
+	old = current->blocked.sig[0];
+
+	siginitset(&current->blocked, newmask & ~(sigmask(SIGKILL)|
+						  sigmask(SIGSTOP)));
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+
+	return old;
+}
+#endif /* __ARCH_WANT_SGETMASK */
+
+#ifdef __ARCH_WANT_SYS_SIGNAL
+/*
+ * For backwards compatibility.  Functionality superseded by sigaction.
+ */
+asmlinkage unsigned long
+sys_signal(int sig, __sighandler_t handler)
+{
+	struct k_sigaction new_sa, old_sa;
+	int ret;
+
+	new_sa.sa.sa_handler = handler;
+	new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
+
+	ret = do_sigaction(sig, &new_sa, &old_sa);
+
+	return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
+}
+#endif /* __ARCH_WANT_SYS_SIGNAL */
+
+#ifdef __ARCH_WANT_SYS_PAUSE
+
+asmlinkage long
+sys_pause(void)
+{
+	current->state = TASK_INTERRUPTIBLE;
+	schedule();
+	return -ERESTARTNOHAND;
+}
+
+#endif
+
+void __init signals_init(void)
+{
+	sigqueue_cachep =
+		kmem_cache_create("sigqueue",
+				  sizeof(struct sigqueue),
+				  __alignof__(struct sigqueue),
+				  SLAB_PANIC, NULL, NULL);
+}