text: #ifndef _LINUX_SIGNAL_H
  #define _LINUX_SIGNAL_H
  
  #include <asm/signal.h>
  #include <asm/siginfo.h>
  
  #ifdef __KERNEL__
  #include <linux/list.h>
  
  struct task_struct;
  
  /* for sysctl */
  extern int print_fatal_signals;
  /*
   * Real Time signals may be queued.
   */
  
  struct sigqueue {
  	struct list_head list;
  	int flags;
  	siginfo_t info;
  	struct user_struct *user;
  };
  
  /* flags values. */
  #define SIGQUEUE_PREALLOC	1
  
  struct sigpending {
  	struct list_head list;
  	sigset_t signal;
  };
  
  /*
   * Define some primitives to manipulate sigset_t.
   */
  
  #ifndef __HAVE_ARCH_SIG_BITOPS
  #include <linux/bitops.h>
  
  /* We don't use <linux/bitops.h> for these because there is no need to
     be atomic.  */
  static inline void sigaddset(sigset_t *set, int _sig)
  {
  	unsigned long sig = _sig - 1;
  	if (_NSIG_WORDS == 1)
  		set->sig[0] |= 1UL << sig;
  	else
  		set->sig[sig / _NSIG_BPW] |= 1UL << (sig % _NSIG_BPW);
  }
  
  static inline void sigdelset(sigset_t *set, int _sig)
  {
  	unsigned long sig = _sig - 1;
  	if (_NSIG_WORDS == 1)
  		set->sig[0] &= ~(1UL << sig);
  	else
  		set->sig[sig / _NSIG_BPW] &= ~(1UL << (sig % _NSIG_BPW));
  }
  
  static inline int sigismember(sigset_t *set, int _sig)
  {
  	unsigned long sig = _sig - 1;
  	if (_NSIG_WORDS == 1)
  		return 1 & (set->sig[0] >> sig);
  	else
  		return 1 & (set->sig[sig / _NSIG_BPW] >> (sig % _NSIG_BPW));
  }
  
  static inline int sigfindinword(unsigned long word)
  {
  	return ffz(~word);
  }
  
  #endif /* __HAVE_ARCH_SIG_BITOPS */
  
  static inline int sigisemptyset(sigset_t *set)
  {
  	extern void _NSIG_WORDS_is_unsupported_size(void);
  	switch (_NSIG_WORDS) {
  	case 4:
  		return (set->sig[3] | set->sig[2] |
  			set->sig[1] | set->sig[0]) == 0;
  	case 2:
  		return (set->sig[1] | set->sig[0]) == 0;
  	case 1:
  		return set->sig[0] == 0;
  	default:
  		_NSIG_WORDS_is_unsupported_size();
  		return 0;
  	}
  }
  
  #define sigmask(sig)	(1UL << ((sig) - 1))
  
  #ifndef __HAVE_ARCH_SIG_SETOPS
  #include <linux/string.h>
  
  #define _SIG_SET_BINOP(name, op)					\
  static inline void name(sigset_t *r, const sigset_t *a, const sigset_t *b) \
  {									\
  	extern void _NSIG_WORDS_is_unsupported_size(void);		\
  	unsigned long a0, a1, a2, a3, b0, b1, b2, b3;			\
  									\
  	switch (_NSIG_WORDS) {						\
  	    case 4:							\
  		a3 = a->sig[3]; a2 = a->sig[2];				\
  		b3 = b->sig[3]; b2 = b->sig[2];				\
  		r->sig[3] = op(a3, b3);					\
  		r->sig[2] = op(a2, b2);					\
  	    case 2:							\
  		a1 = a->sig[1]; b1 = b->sig[1];				\
  		r->sig[1] = op(a1, b1);					\
  	    case 1:							\
  		a0 = a->sig[0]; b0 = b->sig[0];				\
  		r->sig[0] = op(a0, b0);					\
  		break;							\
  	    default:							\
  		_NSIG_WORDS_is_unsupported_size();			\
  	}								\
  }
  
  #define _sig_or(x,y)	((x) | (y))
  _SIG_SET_BINOP(sigorsets, _sig_or)
  
  #define _sig_and(x,y)	((x) & (y))
  _SIG_SET_BINOP(sigandsets, _sig_and)
  
  #define _sig_andn(x,y)	((x) & ~(y))
  _SIG_SET_BINOP(sigandnsets, _sig_andn)
  
  #undef _SIG_SET_BINOP
  #undef _sig_or
  #undef _sig_and
  #undef _sig_andn
  
  #define _SIG_SET_OP(name, op)						\
  static inline void name(sigset_t *set)					\
  {									\
  	extern void _NSIG_WORDS_is_unsupported_size(void);		\
  									\
  	switch (_NSIG_WORDS) {						\
  	    case 4: set->sig[3] = op(set->sig[3]);			\
  		    set->sig[2] = op(set->sig[2]);			\
  	    case 2: set->sig[1] = op(set->sig[1]);			\
  	    case 1: set->sig[0] = op(set->sig[0]);			\
  		    break;						\
  	    default:							\
  		_NSIG_WORDS_is_unsupported_size();			\
  	}								\
  }
  
  #define _sig_not(x)	(~(x))
  _SIG_SET_OP(signotset, _sig_not)
  
  #undef _SIG_SET_OP
  #undef _sig_not
  
  static inline void sigemptyset(sigset_t *set)
  {
  	switch (_NSIG_WORDS) {
  	default:
  		memset(set, 0, sizeof(sigset_t));
  		break;
  	case 2: set->sig[1] = 0;
  	case 1:	set->sig[0] = 0;
  		break;
  	}
  }
  
  static inline void sigfillset(sigset_t *set)
  {
  	switch (_NSIG_WORDS) {
  	default:
  		memset(set, -1, sizeof(sigset_t));
  		break;
  	case 2: set->sig[1] = -1;
  	case 1:	set->sig[0] = -1;
  		break;
  	}
  }
  
  /* Some extensions for manipulating the low 32 signals in particular.  */
  
  static inline void sigaddsetmask(sigset_t *set, unsigned long mask)
  {
  	set->sig[0] |= mask;
  }
  
  static inline void sigdelsetmask(sigset_t *set, unsigned long mask)
  {
  	set->sig[0] &= ~mask;
  }
  
  static inline int sigtestsetmask(sigset_t *set, unsigned long mask)
  {
  	return (set->sig[0] & mask) != 0;
  }
  
  static inline void siginitset(sigset_t *set, unsigned long mask)
  {
  	set->sig[0] = mask;
  	switch (_NSIG_WORDS) {
  	default:
  		memset(&set->sig[1], 0, sizeof(long)*(_NSIG_WORDS-1));
  		break;
  	case 2: set->sig[1] = 0;
  	case 1: ;
  	}
  }
  
  static inline void siginitsetinv(sigset_t *set, unsigned long mask)
  {
  	set->sig[0] = ~mask;
  	switch (_NSIG_WORDS) {
  	default:
  		memset(&set->sig[1], -1, sizeof(long)*(_NSIG_WORDS-1));
  		break;
  	case 2: set->sig[1] = -1;
  	case 1: ;
  	}
  }
  
  #endif /* __HAVE_ARCH_SIG_SETOPS */
  
  static inline void init_sigpending(struct sigpending *sig)
  {
  	sigemptyset(&sig->signal);
  	INIT_LIST_HEAD(&sig->list);
  }
  
  extern void flush_sigqueue(struct sigpending *queue);
  
  /* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
  static inline int valid_signal(unsigned long sig)
  {
  	return sig <= _NSIG ? 1 : 0;
  }
  
  struct timespec;
  struct pt_regs;
  
  extern int next_signal(struct sigpending *pending, sigset_t *mask);
  extern int do_send_sig_info(int sig, struct siginfo *info,
  				struct task_struct *p, bool group);
  extern int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p);
  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;
  
  extern int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, struct pt_regs *regs, void *cookie);
  extern void exit_signals(struct task_struct *tsk);
  
  extern struct kmem_cache *sighand_cachep;
  
  int unhandled_signal(struct task_struct *tsk, int sig);
  
  /*
   * 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 SIGEMT_MASK	rt_sigmask(SIGEMT)
  #else
  #define SIGEMT_MASK	0
  #endif
  
  #if SIGRTMIN > BITS_PER_LONG
  #define rt_sigmask(sig)	(1ULL << ((sig)-1))
  #else
  #define rt_sigmask(sig)	sigmask(sig)
  #endif
  #define siginmask(sig, mask) (rt_sigmask(sig) & (mask))
  
  #define SIG_KERNEL_ONLY_MASK (\
  	rt_sigmask(SIGKILL)   |  rt_sigmask(SIGSTOP))
  
  #define SIG_KERNEL_STOP_MASK (\
  	rt_sigmask(SIGSTOP)   |  rt_sigmask(SIGTSTP)   | \
  	rt_sigmask(SIGTTIN)   |  rt_sigmask(SIGTTOU)   )
  
  #define SIG_KERNEL_COREDUMP_MASK (\
          rt_sigmask(SIGQUIT)   |  rt_sigmask(SIGILL)    | \
  	rt_sigmask(SIGTRAP)   |  rt_sigmask(SIGABRT)   | \
          rt_sigmask(SIGFPE)    |  rt_sigmask(SIGSEGV)   | \
  	rt_sigmask(SIGBUS)    |  rt_sigmask(SIGSYS)    | \
          rt_sigmask(SIGXCPU)   |  rt_sigmask(SIGXFSZ)   | \
  	SIGEMT_MASK				       )
  
  #define SIG_KERNEL_IGNORE_MASK (\
          rt_sigmask(SIGCONT)   |  rt_sigmask(SIGCHLD)   | \
  	rt_sigmask(SIGWINCH)  |  rt_sigmask(SIGURG)    )
  
  #define sig_kernel_only(sig) \
  	(((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_ONLY_MASK))
  #define sig_kernel_coredump(sig) \
  	(((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_COREDUMP_MASK))
  #define sig_kernel_ignore(sig) \
  	(((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_IGNORE_MASK))
  #define sig_kernel_stop(sig) \
  	(((sig) < SIGRTMIN) && siginmask(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) \
  	(!siginmask(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \
  	 (t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL)
  
  void signals_init(void);
  
  #endif /* __KERNEL__ */
  
  #endif /* _LINUX_SIGNAL_H */
  