kernel-signal.c

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	return retval;
}

inline 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 = 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, current->pgrp);
	} else if (pid == -1) {
		int retval = 0, count = 0;
		struct task_struct * p;

		read_lock(&tasklist_lock);
		for_each_task(p) {
			if (p->pid > 1 && p != current) {
				int err = 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.
 */

int
send_sig(int sig, struct task_struct *p, int priv)
{
	return send_sig_info(sig, (void*)(long)(priv != 0), p);
}

void
force_sig(int sig, struct task_struct *p)
{
	force_sig_info(sig, (void*)1L, p);
}

int
kill_pg(pid_t pgrp, int sig, int priv)
{
	return kill_pg_info(sig, (void *)(long)(priv != 0), pgrp);
}

int
kill_sl(pid_t sess, int sig, int priv)
{
	return kill_sl_info(sig, (void *)(long)(priv != 0), sess);
}

int
kill_proc(pid_t pid, int sig, int priv)
{
	return kill_proc_info(sig, (void *)(long)(priv != 0), pid);
}

/*
 * Joy. Or not. Pthread wants us to wake up every thread
 * in our parent group.
 */
static void wake_up_parent(struct task_struct *parent)
{
	struct task_struct *tsk = parent;

	do {
		wake_up_interruptible(&tsk->wait_chldexit);
		tsk = next_thread(tsk);
	} while (tsk != parent);
}

/*
 * Let a parent know about a status change of a child.
 */

void do_notify_parent(struct task_struct *tsk, int sig)
{
	struct siginfo info;
	int why, status;

	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 = tsk->times.tms_utime;
	info.si_stime = tsk->times.tms_stime;

	status = tsk->exit_code & 0x7f;
	why = SI_KERNEL;	/* shouldn't happen */
	switch (tsk->state) {
	case TASK_STOPPED:
		/* FIXME -- can we deduce CLD_TRAPPED or CLD_CONTINUED? */
		if (tsk->ptrace & PT_PTRACED)
			why = CLD_TRAPPED;
		else
			why = CLD_STOPPED;
		break;

	default:
		if (tsk->exit_code & 0x80)
			why = CLD_DUMPED;
		else if (tsk->exit_code & 0x7f)
			why = CLD_KILLED;
		else {
			why = CLD_EXITED;
			status = tsk->exit_code >> 8;
		}
		break;
	}
	info.si_code = why;
	info.si_status = status;

	send_sig_info(sig, &info, tsk->p_pptr);
	wake_up_parent(tsk->p_pptr);
}


/*
 * We need the tasklist lock because it's the only
 * thing that protects out "parent" pointer.
 *
 * exit.c calls "do_notify_parent()" directly, because
 * it already has the tasklist lock.
 */
void
notify_parent(struct task_struct *tsk, int sig)
{
	read_lock(&tasklist_lock);
	do_notify_parent(tsk, sig);
	read_unlock(&tasklist_lock);
}

EXPORT_SYMBOL(dequeue_signal);
EXPORT_SYMBOL(flush_signals);
EXPORT_SYMBOL(force_sig);
EXPORT_SYMBOL(force_sig_info);
EXPORT_SYMBOL(kill_pg);
EXPORT_SYMBOL(kill_pg_info);
EXPORT_SYMBOL(kill_proc);
EXPORT_SYMBOL(kill_proc_info);
EXPORT_SYMBOL(kill_sl);
EXPORT_SYMBOL(kill_sl_info);
EXPORT_SYMBOL(notify_parent);
EXPORT_SYMBOL(recalc_sigpending);
EXPORT_SYMBOL(send_sig);
EXPORT_SYMBOL(send_sig_info);
EXPORT_SYMBOL(block_all_signals);
EXPORT_SYMBOL(unblock_all_signals);


/*
 * System call entry points.
 */

/*
 * 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)
 */

asmlinkage long
sys_rt_sigprocmask(int how, sigset_t *set, sigset_t *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));

		spin_lock_irq(&current->sigmask_lock);
		old_set = current->blocked;

		error = 0;
		switch (how) {
		default:
			error = -EINVAL;
			break;
		case SIG_BLOCK:
			sigorsets(&new_set, &old_set, &new_set);
			break;
		case SIG_UNBLOCK:
			signandsets(&new_set, &old_set, &new_set);
			break;
		case SIG_SETMASK:
			break;
		}

		current->blocked = new_set;
		recalc_sigpending(current);
		spin_unlock_irq(&current->sigmask_lock);
		if (error)
			goto out;
		if (oset)
			goto set_old;
	} else if (oset) {
		spin_lock_irq(&current->sigmask_lock);
		old_set = current->blocked;
		spin_unlock_irq(&current->sigmask_lock);

	set_old:
		error = -EFAULT;
		if (copy_to_user(oset, &old_set, sizeof(*oset)))
			goto out;
	}
	error = 0;
out:
	return error;
}

long do_sigpending(void *set, unsigned long sigsetsize)
{
	long error = -EINVAL;
	sigset_t pending;

	if (sigsetsize > sizeof(sigset_t))
		goto out;

	spin_lock_irq(&current->sigmask_lock);
	sigandsets(&pending, &current->blocked, &current->pending.signal);
	spin_unlock_irq(&current->sigmask_lock);

	error = -EFAULT;
	if (!copy_to_user(set, &pending, sigsetsize))
		error = 0;
out:
	return error;
}	

asmlinkage long
sys_rt_sigpending(sigset_t *set, size_t sigsetsize)
{
	return do_sigpending(set, sigsetsize);
}

asmlinkage long
sys_rt_sigtimedwait(const sigset_t *uthese, siginfo_t *uinfo,
		    const struct timespec *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->sigmask_lock);
	sig = dequeue_signal(&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.  */
			sigset_t oldblocked = current->blocked;
			sigandsets(&current->blocked, &current->blocked, &these);
			recalc_sigpending(current);
			spin_unlock_irq(&current->sigmask_lock);

			current->state = TASK_INTERRUPTIBLE;
			timeout = schedule_timeout(timeout);

			spin_lock_irq(&current->sigmask_lock);
			sig = dequeue_signal(&these, &info);
			current->blocked = oldblocked;
			recalc_sigpending(current);
		}
	}
	spin_unlock_irq(&current->sigmask_lock);

	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->pid;
	info.si_uid = current->uid;

	return kill_something_info(sig, &info, pid);
}

asmlinkage long
sys_rt_sigqueueinfo(int pid, int sig, siginfo_t *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 == SIGKILL || sig == SIGSTOP)))
		return -EINVAL;

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

	spin_lock(&current->sig->siglock);

	if (oact)
		*oact = *k;

	if (act) {
		*k = *act;
		sigdelsetmask(&k->sa.sa_mask, sigmask(SIGKILL) | sigmask(SIGSTOP));

		/*
		 * 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"
		 *
		 * Note the silly behaviour of SIGCHLD: SIG_IGN means that the
		 * signal isn't actually ignored, but does automatic child
		 * reaping, while SIG_DFL is explicitly said by POSIX to force
		 * the signal to be ignored.
		 */

		if (k->sa.sa_handler == SIG_IGN
		    || (k->sa.sa_handler == SIG_DFL
			&& (sig == SIGCONT ||
			    sig == SIGCHLD ||
			    sig == SIGWINCH))) {
			spin_lock_irq(&current->sigmask_lock);
			if (rm_sig_from_queue(sig, current))
				recalc_sigpending(current);
			spin_unlock_irq(&current->sigmask_lock);
		}
	}

	spin_unlock(&current->sig->siglock);
	return 0;
}

int 
do_sigaltstack (const stack_t *uss, stack_t *uoss, unsigned long sp)
{
	stack_t oss;
	int error;

	if (uoss) {
		oss.ss_sp = (void *) current->sas_ss_sp;
		oss.ss_size = current->sas_ss_size;
		oss.ss_flags = sas_ss_flags(sp);
	}

	if (uss) {
		void *ss_sp;
		size_t ss_size;
		int ss_flags;

		error = -EFAULT;
		if (verify_area(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;
}

asmlinkage long
sys_sigpending(old_sigset_t *set)
{
	return do_sigpending(set, sizeof(*set));
}

#if !defined(__alpha__)
/* Alpha has its own versions with special arguments.  */

asmlinkage long
sys_sigprocmask(int how, old_sigset_t *set, old_sigset_t *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->sigmask_lock);
		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(current);
		spin_unlock_irq(&current->sigmask_lock);
		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;
}

#ifndef __sparc__
asmlinkage long
sys_rt_sigaction(int sig, const struct sigaction *act, struct sigaction *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 /* __sparc__ */
#endif

#if !defined(__alpha__) && !defined(__ia64__)
/*
 * 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->sigmask_lock);
	old = current->blocked.sig[0];

	siginitset(&current->blocked, newmask & ~(sigmask(SIGKILL)|
						  sigmask(SIGSTOP)));
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);

	return old;
}
#endif /* !defined(__alpha__) */

#if !defined(__alpha__) && !defined(__ia64__) && !defined(__mips__)
/*
 * 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 /* !alpha && !__ia64__ && !defined(__mips__) */