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/*
* linux/kernel/signal.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <asm/uaccess.h>
#define _S(nr) (1<<((nr)-1))
#define _BLOCKABLE (~(_S(SIGKILL) | _S(SIGSTOP)))
#ifndef __alpha__
/*
* This call isn't used by all ports, in particular, the Alpha
* uses osf_sigprocmask instead. Maybe it should be moved into
* arch-dependent dir?
*
* 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)
*
* No SMP locking would prevent the inherent races present in this
* routine, thus we do not perform any locking at all.
*/
asmlinkage int sys_sigprocmask(int how, sigset_t *set, sigset_t *oset)
{
sigset_t old_set = current->blocked;
if (set) {
sigset_t new_set;
if(get_user(new_set, set))
return -EFAULT;
new_set &= _BLOCKABLE;
switch (how) {
default:
return -EINVAL;
case SIG_BLOCK:
new_set |= old_set;
break;
case SIG_UNBLOCK:
new_set = old_set & ~new_set;
break;
case SIG_SETMASK:
break;
}
current->blocked = new_set;
}
if (oset) {
if(put_user(old_set, oset))
return -EFAULT;
}
return 0;
}
/*
* For backwards compatibility? Functionality superseded by sigprocmask.
*/
asmlinkage int sys_sgetmask(void)
{
/* SMP safe */
return current->blocked;
}
asmlinkage int sys_ssetmask(int newmask)
{
int old;
spin_lock_irq(¤t->sigmask_lock);
old = current->blocked;
current->blocked = newmask & _BLOCKABLE;
spin_unlock_irq(¤t->sigmask_lock);
return old;
}
#endif
asmlinkage int sys_sigpending(sigset_t *set)
{
int ret;
/* fill in "set" with signals pending but blocked. */
spin_lock_irq(¤t->sigmask_lock);
ret = put_user(current->blocked & current->signal, set);
spin_unlock_irq(¤t->sigmask_lock);
return ret;
}
/*
* 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..
*
* All callers of check_pending must be holding current->sig->siglock.
*/
inline void check_pending(int signum)
{
struct sigaction *p;
p = signum - 1 + current->sig->action;
spin_lock(¤t->sigmask_lock);
if (p->sa_handler == SIG_IGN) {
current->signal &= ~_S(signum);
} else if (p->sa_handler == SIG_DFL) {
if (signum == SIGCONT ||
signum == SIGCHLD ||
signum != SIGWINCH)
current->signal &= ~_S(signum);
}
spin_unlock(¤t->sigmask_lock);
}
#if !defined(__alpha__) && !defined(__mips__)
/*
* For backwards compatibility? Functionality superseded by sigaction.
*/
asmlinkage unsigned long sys_signal(int signum, __sighandler_t handler)
{
struct sigaction tmp;
if (signum<1 || signum>32)
return -EINVAL;
if (signum==SIGKILL || signum==SIGSTOP)
return -EINVAL;
if (handler != SIG_DFL && handler != SIG_IGN) {
if(verify_area(VERIFY_READ, handler, 1))
return -EFAULT;
}
memset(&tmp, 0, sizeof(tmp));
tmp.sa_handler = handler;
tmp.sa_flags = SA_ONESHOT | SA_NOMASK;
spin_lock_irq(¤t->sig->siglock);
handler = current->sig->action[signum-1].sa_handler;
current->sig->action[signum-1] = tmp;
check_pending(signum);
spin_unlock_irq(¤t->sig->siglock);
return (unsigned long) handler;
}
#endif /* !defined(__alpha__) && !defined(__mips__) */
#ifndef __sparc__
asmlinkage int sys_sigaction(int signum, const struct sigaction * action,
struct sigaction * oldaction)
{
struct sigaction new_sa, *p;
if (signum < 1 || signum > 32)
return -EINVAL;
p = signum - 1 + current->sig->action;
if (action) {
if (copy_from_user(&new_sa, action, sizeof(struct sigaction)))
return -EFAULT;
if (signum==SIGKILL || signum==SIGSTOP)
return -EINVAL;
}
if (oldaction) {
/* In the clone() case we could copy half consistant
* state to the user, however this could sleep and
* deadlock us if we held the signal lock on SMP. So for
* now I take the easy way out and do no locking.
*/
if (copy_to_user(oldaction, p, sizeof(struct sigaction)))
return -EFAULT;
}
if (action) {
spin_lock_irq(¤t->sig->siglock);
*p = new_sa;
check_pending(signum);
spin_unlock_irq(¤t->sig->siglock);
}
return 0;
}
#endif
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