FreeBSD/Linux Kernel Cross Reference
sys/bsd/kern/kern_sig.c

     /*
      * Copyright (c) 2000-2001 Apple Computer, Inc. All rights reserved.
      *
      * @APPLE_LICENSE_HEADER_START@
      * 
      * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
      * 
      * This file contains Original Code and/or Modifications of Original Code
      * as defined in and that are subject to the Apple Public Source License
     * Version 2.0 (the 'License'). You may not use this file except in
     * compliance with the License. Please obtain a copy of the License at
     * http://www.opensource.apple.com/apsl/ and read it before using this
     * file.
     * 
     * The Original Code and all software distributed under the License are
     * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
     * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
     * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
     * Please see the License for the specific language governing rights and
     * limitations under the License.
     * 
     * @APPLE_LICENSE_HEADER_END@
     */
    /* Copyright (c) 1995-1998 Apple Computer, Inc. All Rights Reserved */
    /*
     * Copyright (c) 1982, 1986, 1989, 1991, 1993
     *      The Regents of the University of California.  All rights reserved.
     * (c) UNIX System Laboratories, Inc.
     * All or some portions of this file are derived from material licensed
     * to the University of California by American Telephone and Telegraph
     * Co. or Unix System Laboratories, Inc. and are reproduced herein with
     * the permission of UNIX System Laboratories, Inc.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      @(#)kern_sig.c  8.7 (Berkeley) 4/18/94
     */
    
    #define SIGPROP         /* include signal properties table */
    #include <sys/param.h>
    #include <sys/resourcevar.h>
    #include <sys/namei.h>
    #include <sys/vnode.h>
    #include <sys/proc.h>
    #include <sys/systm.h>
    #include <sys/timeb.h>
    #include <sys/times.h>
    #include <sys/buf.h>
    #include <sys/acct.h>
    #include <sys/file.h>
    #include <sys/kernel.h>
    #include <sys/wait.h>
    #include <sys/signalvar.h>
    #if KTRACE
    #include <sys/ktrace.h>
    #endif
    #include <sys/syslog.h>
    #include <sys/stat.h>
    #include <sys/lock.h>
    #include <sys/kdebug.h>
    
    #include <sys/mount.h>
    
    #include <kern/cpu_number.h>
    
    #include <sys/vm.h>
    #include <sys/user.h>           /* for coredump */
    #include <kern/ast.h>           /* for APC support */
    #include <kern/thread.h>
    #include <kern/sched_prim.h>
    #include <kern/thread_call.h>
    #include <mach/exception.h>
   
   extern void doexception(int exc, int code, int sub);
   
   void stop __P((struct proc *p));
   int cansignal __P((struct proc *, struct pcred *, struct proc *, int));
   int killpg1 __P((struct proc *, int, int, int));
   void sigexit_locked __P((struct proc *, int));
   int setsigvec __P((struct proc *, int, struct __sigaction *));
   void exit1 __P((struct proc *, int, int *));
   int signal_lock __P((struct proc *));
   int signal_unlock __P((struct proc *));
   void signal_setast __P((thread_act_t));
   void psignal_lock __P((struct proc *, int, int));
   void psignal_uthread __P((thread_act_t, int));
   kern_return_t do_bsdexception(int, int, int);
   
   static int      filt_sigattach(struct knote *kn);
   static void     filt_sigdetach(struct knote *kn);
   static int      filt_signal(struct knote *kn, long hint);
   
   struct filterops sig_filtops =
           { 0, filt_sigattach, filt_sigdetach, filt_signal };
   
   #if SIGNAL_DEBUG
   void ram_printf __P((int));
   int ram_debug=0;
   unsigned int rdebug_proc=0;
   void
   ram_printf(int x)
   {
       printf("x is %d",x);
   
   }
   #endif /* SIGNAL_DEBUG */
   
   int
   signal_lock(struct proc *p)
   {
   int error = 0;
   #if DIAGNOSTIC
   #if SIGNAL_DEBUG
   #ifdef __ppc__
           {
               int register sp, *fp, numsaved; 
    
               __asm__ volatile("mr %0,r1" : "=r" (sp));
   
               fp = (int *)*((int *)sp);
               for (numsaved = 0; numsaved < 3; numsaved++) {
                   p->lockpc[numsaved] = fp[2];
                   if ((int)fp <= 0)
                           break;
                   fp = (int *)*fp;
               }
           }
   #endif /* __ppc__ */       
   #endif /* SIGNAL_DEBUG */
   #endif /* DIAGNOSTIC */
   
   siglock_retry:
           /* TBD:  check p last arg */
           error = lockmgr(&p->signal_lock, LK_EXCLUSIVE, 0, (struct proc *)p);
           if (error == EINTR)
                   goto siglock_retry;
           return(error);
   }
   
   int
   signal_unlock(struct proc *p)
   {
   #if DIAGNOSTIC
   #if SIGNAL_DEBUG
   #ifdef __ppc__
           {
               int register sp, *fp, numsaved; 
    
               __asm__ volatile("mr %0,r1" : "=r" (sp));
   
               fp = (int *)*((int *)sp);
               for (numsaved = 0; numsaved < 3; numsaved++) {
                   p->unlockpc[numsaved] = fp[2];
                   if ((int)fp <= 0)
                           break;
                   fp = (int *)*fp;
               }
           }
   #endif /* __ppc__ */       
   #endif /* SIGNAL_DEBUG */
   #endif /* DIAGNOSTIC */
   
           /* TBD:  check p last arg */
           return(lockmgr(&p->signal_lock, LK_RELEASE, (simple_lock_t)0, (struct proc *)p));
   }
   
   void
   signal_setast(sig_actthread)
   thread_act_t sig_actthread;
   {
           act_set_astbsd(sig_actthread);
   }
   
   /*
    * Can process p, with pcred pc, send the signal signum to process q?
    */
   int
   cansignal(p, pc, q, signum)
           struct proc *p;
           struct pcred *pc;
           struct proc *q;
           int signum;
   {
           /* you can signal yourself */
           if (p == q)
                   return(1);
   
           if (pc->pc_ucred->cr_uid == 0)
                   return (1);             /* root can always signal */
   
           if (signum == SIGCONT && q->p_session == p->p_session)
                   return (1);             /* SIGCONT in session */
   
           /*
            * Using kill(), only certain signals can be sent to setugid
            * child processes
            */
           if (q->p_flag & P_SUGID) {
                   switch (signum) {
                   case 0:
                   case SIGKILL:
                   case SIGINT:
                   case SIGTERM:
                   case SIGSTOP:
                   case SIGTTIN:
                   case SIGTTOU:
                   case SIGTSTP:
                   case SIGHUP:
                   case SIGUSR1:
                   case SIGUSR2:
                           if (pc->p_ruid == q->p_cred->p_ruid ||
                               pc->pc_ucred->cr_uid == q->p_cred->p_ruid ||
                               pc->p_ruid == q->p_ucred->cr_uid ||
                               pc->pc_ucred->cr_uid == q->p_ucred->cr_uid)
                                   return (1);
                   }
                   return (0);
           }
   
           /* XXX
            * because the P_SUGID test exists, this has extra tests which
            * could be removed.
            */
           if (pc->p_ruid == q->p_cred->p_ruid ||
               pc->p_ruid == q->p_cred->p_svuid ||
               pc->pc_ucred->cr_uid == q->p_cred->p_ruid ||
               pc->pc_ucred->cr_uid == q->p_cred->p_svuid ||
               pc->p_ruid == q->p_ucred->cr_uid ||
               pc->pc_ucred->cr_uid == q->p_ucred->cr_uid)
                   return (1);
           return (0);
   }
   
   struct sigaction_args {
           int     signum;
           struct __sigaction *nsa;
           struct sigaction *osa;
   };
   
   /* ARGSUSED */
   int
   sigaction(p, uap, retval)
           struct proc *p;
           register struct sigaction_args *uap;
           register_t *retval;
   {
           struct sigaction vec;
           struct __sigaction __vec;
   
           register struct sigaction *sa;
           register struct sigacts *ps = p->p_sigacts;
           register int signum;
           int bit, error=0;
   
           signum = uap->signum;
           if (signum <= 0 || signum >= NSIG ||
               signum == SIGKILL || signum == SIGSTOP)
                   return (EINVAL);
           sa = &vec;
           if (uap->osa) {
                   sa->sa_handler = ps->ps_sigact[signum];
                   sa->sa_mask = ps->ps_catchmask[signum];
                   bit = sigmask(signum);
                   sa->sa_flags = 0;
                   if ((ps->ps_sigonstack & bit) != 0)
                           sa->sa_flags |= SA_ONSTACK;
                   if ((ps->ps_sigintr & bit) == 0)
                           sa->sa_flags |= SA_RESTART;
                   if (ps->ps_siginfo & bit)
                           sa->sa_flags |= SA_SIGINFO;
                   if (ps->ps_signodefer & bit)
                           sa->sa_flags |= SA_NODEFER;
                   if (ps->ps_64regset & bit)
                           sa->sa_flags |= SA_64REGSET;
                   if ((signum == SIGCHLD) && (p->p_flag & P_NOCLDSTOP))
                           sa->sa_flags |= SA_NOCLDSTOP;
                   if ((signum == SIGCHLD) && (p->p_flag & P_NOCLDWAIT))
                           sa->sa_flags |= SA_NOCLDWAIT;
                   if (error = copyout((caddr_t)sa, (caddr_t)uap->osa,
                       sizeof (vec)))
                           return (error);
           }
           if (uap->nsa) {
                   if (error = copyin((caddr_t)uap->nsa, (caddr_t)&__vec,
                       sizeof (__vec)))
                           return (error);
                   error = setsigvec(p, signum, &__vec);
           }
           return (error);
   }
   
   /* Routines to manipulate bits on all threads */
   int
   clear_procsiglist(struct proc *p,  int bit)
   {
           struct uthread * uth;
           thread_act_t thact;
   
           signal_lock(p);
   
           if ((p->p_flag & P_INVFORK) && p->p_vforkact) {
                   thact = p->p_vforkact;  
                   uth = (struct uthread *)get_bsdthread_info(thact);
                   if (uth) {
                           uth->uu_siglist &= ~bit;
                   }
                   p->p_siglist &= ~bit;
                   signal_unlock(p);
                   return(0);
           } 
   
           TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) {
                   uth->uu_siglist &= ~bit;
           }
           p->p_siglist &= ~bit;
           signal_unlock(p);
           return(0);
   }
   
   int
   unblock_procsigmask(struct proc *p,  int bit)
   {
           struct uthread * uth;
           thread_act_t thact;
   
           signal_lock(p);
           if ((p->p_flag & P_INVFORK) && p->p_vforkact) {
                   thact = p->p_vforkact;  
                   uth = (struct uthread *)get_bsdthread_info(thact);
                   if (uth) {
                           uth->uu_sigmask &= ~bit;
                   }
                   p->p_sigmask &= ~bit;
                   signal_unlock(p);
                   return(0);
           } 
           TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) {
                   uth->uu_sigmask &= ~bit;
           }
           p->p_sigmask &= ~bit;
           signal_unlock(p);
           return(0);
   }
   
   
   int
   block_procsigmask(struct proc *p,  int bit)
   {
           struct uthread * uth;
           thread_act_t thact;
   
           signal_lock(p);
           if ((p->p_flag & P_INVFORK) && p->p_vforkact) {
                   thact = p->p_vforkact;  
                   uth = (struct uthread *)get_bsdthread_info(thact);
                   if (uth) {
                           uth->uu_sigmask |= bit;
                   }
                   p->p_sigmask |=  bit;
                   signal_unlock(p);
                   return(0);
           } 
           TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) {
                   uth->uu_sigmask |= bit;
           }
           p->p_sigmask |=  bit;
           signal_unlock(p);
           return(0);
   }
   int
   set_procsigmask(struct proc *p,  int bit)
   {
           struct uthread * uth;
           thread_act_t thact;
   
           signal_lock(p);
           if ((p->p_flag & P_INVFORK) && p->p_vforkact) {
                   thact = p->p_vforkact;  
                   uth = (struct uthread *)get_bsdthread_info(thact);
                   if (uth) {
                           uth->uu_sigmask = bit;
                   }
                   p->p_sigmask =  bit;
                   signal_unlock(p);
                   return(0);
           } 
           TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) {
                   uth->uu_sigmask = bit;
           }
           p->p_sigmask =  bit;
           signal_unlock(p);
           return(0);
   }
   
   int
   setsigvec(p, signum, sa)
           register struct proc *p;
           int signum;
           register struct __sigaction *sa;
   {
           register struct sigacts *ps = p->p_sigacts;
           register int bit;
   
           if ((signum == SIGKILL || signum == SIGSTOP) &&
                   sa->sa_handler != SIG_DFL)
                   return(EINVAL);
           bit = sigmask(signum);
           /*
            * Change setting atomically.
            */
           ps->ps_sigact[signum] = sa->sa_handler;
           ps->ps_trampact[signum] = (sig_t) sa->sa_tramp;
           ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask;
           if (sa->sa_flags & SA_SIGINFO)
                   ps->ps_siginfo |= bit;
           else
                   ps->ps_siginfo &= ~bit;
           if (sa->sa_flags & SA_64REGSET)
                   ps->ps_64regset |= bit;
           else
                   ps->ps_64regset &= ~bit;
           if ((sa->sa_flags & SA_RESTART) == 0)
                   ps->ps_sigintr |= bit;
           else
                   ps->ps_sigintr &= ~bit;
           if (sa->sa_flags & SA_ONSTACK)
                   ps->ps_sigonstack |= bit;
           else
                   ps->ps_sigonstack &= ~bit;
           if (sa->sa_flags & SA_USERTRAMP)
                   ps->ps_usertramp |= bit;
           else
                   ps->ps_usertramp &= ~bit;
           if (sa->sa_flags & SA_RESETHAND)
                   ps->ps_sigreset |= bit;
           else
                   ps->ps_sigreset &= ~bit;
           if (sa->sa_flags & SA_NODEFER)
                   ps->ps_signodefer |= bit;
           else
                   ps->ps_signodefer &= ~bit;
           if (signum == SIGCHLD) {
                   if (sa->sa_flags & SA_NOCLDSTOP)
                           p->p_flag |= P_NOCLDSTOP;
                   else
                           p->p_flag &= ~P_NOCLDSTOP;
                   if ((sa->sa_flags & SA_NOCLDWAIT) || (sa->sa_handler == SIG_IGN))
                           p->p_flag |= P_NOCLDWAIT;
                   else
                           p->p_flag &= ~P_NOCLDWAIT;
           }
   
   #ifdef __ppc__ 
           if (signum == SIGFPE) {
                   if (sa->sa_handler == SIG_DFL || sa->sa_handler == SIG_IGN) 
                           thread_enable_fpe(current_act(), 0);
                   else
                           thread_enable_fpe(current_act(), 1);
           }
   #endif  /* __ppc__ */
           /*
            * Set bit in p_sigignore for signals that are set to SIG_IGN,
            * and for signals set to SIG_DFL where the default is to ignore.
            * However, don't put SIGCONT in p_sigignore,
            * as we have to restart the process.
            */
           if (sa->sa_handler == SIG_IGN ||
               (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) {
   
                   clear_procsiglist(p, bit);
                   if (signum != SIGCONT)
                           p->p_sigignore |= bit;  /* easier in psignal */
                   p->p_sigcatch &= ~bit;
           } else {
                   p->p_sigignore &= ~bit;
                   if (sa->sa_handler == SIG_DFL)
                           p->p_sigcatch &= ~bit;
                   else
                           p->p_sigcatch |= bit;
           }
           return(0);
   }
   
   /*
    * Initialize signal state for process 0;
    * set to ignore signals that are ignored by default.
    */
   void
   siginit(p)
           struct proc *p;
   {
           register int i;
   
           for (i = 0; i < NSIG; i++)
                   if (sigprop[i] & SA_IGNORE && i != SIGCONT)
                           p->p_sigignore |= sigmask(i);
   }
   
   /*
    * Reset signals for an exec of the specified process.
    */
   void
   execsigs(p, thr_act)
           register struct proc *p;
           register thread_act_t thr_act;
   {
           register struct sigacts *ps = p->p_sigacts;
           register int nc, mask;
           struct uthread *ut;
   
           /*
            * Reset caught signals.  Held signals remain held
            * through p_sigmask (unless they were caught,
            * and are now ignored by default).
            */
           while (p->p_sigcatch) {
                   nc = ffs((long)p->p_sigcatch);
                   mask = sigmask(nc);
                   p->p_sigcatch &= ~mask;
                   if (sigprop[nc] & SA_IGNORE) {
                           if (nc != SIGCONT)
                                   p->p_sigignore |= mask;
                           if (thr_act){
                                   ut = (struct uthread *)get_bsdthread_info(thr_act);
                                   ut->uu_siglist &= ~mask;
                                   p->p_siglist &= ~mask;
                           } else
                                   clear_procsiglist(p, mask);
                   }
                   ps->ps_sigact[nc] = SIG_DFL;
           }
           /*
            * Reset stack state to the user stack.
            * Clear set of signals caught on the signal stack.
            */
           ps->ps_sigstk.ss_flags = SA_DISABLE;
           ps->ps_sigstk.ss_size = 0;
           ps->ps_sigstk.ss_sp = 0;
           ps->ps_flags = 0;
   }
   
   /*
    * Manipulate signal mask.
    * Note that we receive new mask, not pointer,
    * and return old mask as return value;
    * the library stub does the rest.
    */
   struct sigprocmask_args {
           int     how;
           sigset_t *mask;
           sigset_t * omask;
   };
   int
   sigprocmask(p, uap, retval)
           register struct proc *p;
           struct sigprocmask_args *uap;
           register_t *retval;
   {
           int error = 0;
           sigset_t oldmask, nmask;
           sigset_t * omask = uap->omask;
           struct uthread *ut;
   
           ut = (struct uthread *)get_bsdthread_info(current_act());
           oldmask  = ut->uu_sigmask;
   
           if (uap->mask == (sigset_t *)0) {
                   /* just want old mask */
                   goto out;
           }
           error = copyin((caddr_t)uap->mask, &nmask, sizeof(sigset_t));
           if (error)
                   goto out;
   
           switch (uap->how) {
           case SIG_BLOCK:
                   block_procsigmask(p, (nmask & ~sigcantmask));
                   signal_setast(current_act());
                   break;
   
           case SIG_UNBLOCK:
                   unblock_procsigmask(p, (nmask & ~sigcantmask));
                   signal_setast(current_act());
                   break;
   
           case SIG_SETMASK:
                   set_procsigmask(p, (nmask & ~sigcantmask));
                   signal_setast(current_act());
                   break;
           
           default:
                   error = EINVAL;
                   break;
           }
   out:
           if (!error && omask)
                   copyout(&oldmask, omask, sizeof(sigset_t));
           return (error);
   }
   
   struct sigpending_args {
           struct sigvec *osv;
   };
   int
   sigpending(p, uap, retval)
           struct proc *p;
           register struct sigpending_args *uap;
           register_t *retval;
   {
           struct uthread *ut;
           sigset_t pendlist;
   
           ut = (struct uthread *)get_bsdthread_info(current_act());
           pendlist = ut->uu_siglist;
   
           if (uap->osv)
                   copyout(&pendlist, uap->osv, sizeof(sigset_t));
           return(0);
   }
   
   #if COMPAT_43
   /*
    * Generalized interface signal handler, 4.3-compatible.
    */
   struct osigvec_args {
           int signum;
           struct sigvec *nsv;
           struct sigvec *osv;
   };
   /* ARGSUSED */
   int
   osigvec(p, uap, retval)
           struct proc *p;
           register struct osigvec_args *uap;
           register_t *retval;
   {
           struct sigvec __vec;
           struct sigvec vec;
           register struct sigacts *ps = p->p_sigacts;
           register struct sigvec *sv;
           register int signum;
           int bit, error=0;
   
   #if 0
           signum = uap->signum;
           if (signum <= 0 || signum >= NSIG ||
               signum == SIGKILL || signum == SIGSTOP)
                   return (EINVAL);
           sv = &vec;
           if (uap->osv) {
                   *(sig_t *)&sv->sv_handler = ps->ps_sigact[signum];
                   sv->sv_mask = ps->ps_catchmask[signum];
                   bit = sigmask(signum);
                   sv->sv_flags = 0;
                   if ((ps->ps_sigonstack & bit) != 0)
                           sv->sv_flags |= SV_ONSTACK;
                   if ((ps->ps_sigintr & bit) != 0)
                           sv->sv_flags |= SV_INTERRUPT;
                           if (p->p_flag & P_NOCLDSTOP)
                                   sv->sv_flags |= SA_NOCLDSTOP;
                   if (error = copyout((caddr_t)sv, (caddr_t)uap->osv,
                       sizeof (vec)))
                           return (error);
           }
           if (uap->nsv) {
                   if (error = copyin((caddr_t)uap->nsv, (caddr_t)sv,
                       sizeof (vec)))
                           return (error);
                   sv->sv_flags ^= SA_RESTART;     /* opposite of SV_INTERRUPT */
                   error = setsigvec(p, signum, (struct sigaction *)sv);
           }
   #else
   error = ENOSYS;
   #endif
           return (error);
   }
   
   struct osigblock_args {
           int mask;
   };
   int
   osigblock(p, uap, retval)
           register struct proc *p;
           struct osigblock_args *uap;
           register_t *retval;
   {
           struct uthread * uth = get_bsdthread_info(current_act());
   
           *retval = uth->uu_sigmask;
           uth->uu_sigmask |= (uap->mask & ~sigcantmask);
           return (0);
   }
   
   struct osigsetmask_args {
           int mask;
   };
   int
   osigsetmask(p, uap, retval)
           struct proc *p;
           struct osigsetmask_args *uap;
           register_t *retval;
   {
           struct uthread * uth = get_bsdthread_info(current_act());
   
           *retval = uth->uu_sigmask;
           uth->uu_sigmask = (uap->mask & ~sigcantmask);
           return (0);
   }
   #endif /* COMPAT_43 */
   
   /*
    * Suspend process until signal, providing mask to be set
    * in the meantime.  Note nonstandard calling convention:
    * libc stub passes mask, not pointer, to save a copyin.
    */
   
   int
   sigcontinue(error)
   {
           struct uthread *ut = get_bsdthread_info(current_act());
     unix_syscall_return(EINTR);
   }
   
   struct sigsuspend_args {
           sigset_t mask;
   };
   
   /* ARGSUSED */
   int
   sigsuspend(p, uap, retval)
           register struct proc *p;
           struct sigsuspend_args *uap;
           register_t *retval;
   {
           register struct sigacts *ps = p->p_sigacts;
           struct uthread *ut;
   
           ut = (struct uthread *)get_bsdthread_info(current_act());
   
           /*
            * When returning from sigpause, we want
            * the old mask to be restored after the
            * signal handler has finished.  Thus, we
            * save it here and mark the sigacts structure
            * to indicate this.
            */
           ut->uu_oldmask = ut->uu_sigmask;
           ut->uu_flag |= USAS_OLDMASK;
           ut->uu_sigmask = (uap->mask & ~sigcantmask);
           (void) tsleep0((caddr_t) p, PPAUSE|PCATCH, "pause", 0, sigcontinue);
           /* always return EINTR rather than ERESTART... */
           return (EINTR);
   }
   
   struct __disable_thsignal_args {
           int value;
   };
   
   int
   __disable_threadsignal(p, uap, retval)
           struct proc *p;
           register struct __disable_thsignal_args *uap;
           register_t *retval;
   {
           struct uthread *uth;
   
           uth = (struct uthread *)get_bsdthread_info(current_act());
   
           /* No longer valid to have any signal delivered */
           signal_lock(p);
           uth->uu_flag |= UNO_SIGMASK;
           signal_unlock(p);
   
           return(0);
   
   }
   
   struct pthread_kill_args {
           void * thread_port;
           int sig;
   };
   
   int 
   __pthread_kill(p, uap, retval) 
           struct proc *p;
           register struct pthread_kill_args *uap;
           register_t *retval;
   {
           thread_act_t target_act;
           int error = 0;
           int signum = uap->sig;
           struct uthread *uth;
   
           target_act = (thread_act_t)port_name_to_act(uap->thread_port);
   
           if (target_act == THR_ACT_NULL)
                   return (ESRCH);
           if ((u_int)signum >= NSIG) {
                   error = EINVAL;
                   goto out;
           }
   
           uth = (struct uthread *)get_bsdthread_info(target_act);
   
           if (uth->uu_flag & UNO_SIGMASK) {
                   error = ESRCH;
                   goto out;
           }
   
           if (signum)
                   psignal_uthread(target_act, signum);
   out:
           act_deallocate(target_act);
           return (error);
   }
   
   
   struct pthread_sigmask_args {
           int how;
           const sigset_t  *set;
           sigset_t * oset;
   };
   int 
   pthread_sigmask(p, uap, retval)
           register struct proc *p;
           register struct pthread_sigmask_args *uap;
           register_t *retval;
   {
           int how = uap->how;
           const sigset_t  *set = uap->set;
           sigset_t  * oset = uap->oset;
           const sigset_t nset;
           int error = 0;
           struct uthread *ut;
           sigset_t  oldset;
   
           ut = (struct uthread *)get_bsdthread_info(current_act());
           oldset = ut->uu_sigmask;
   
           if (set == (sigset_t *) 0) {
                   /* need only old mask */
                   goto out;
           }
   
           error = copyin((caddr_t)set, (caddr_t)&nset, sizeof(sigset_t));
           if (error)
                   goto out;
   
           switch (uap->how) {
           case SIG_BLOCK:
                   ut->uu_sigmask |= (nset & ~sigcantmask);
                   break;
   
           case SIG_UNBLOCK:
                   ut->uu_sigmask &= ~(nset);
                   signal_setast(current_act());
                   break;
   
           case SIG_SETMASK:
                   ut->uu_sigmask = (nset & ~sigcantmask);
                   signal_setast(current_act());
                   break;
           
           default:
                   error = EINVAL;
   
           }
   out:
           if (!error && oset)
                   copyout((caddr_t)&oldset, (caddr_t)oset, sizeof(sigset_t));
   
           return(error);
   }
   
   
   struct sigwait_args {
           const sigset_t  *set;
           int *sig;
   };
   
   int 
   sigwait(p, uap, retval)
           register struct proc *p;
           register struct sigwait_args *uap;
           register_t *retval;
   {
           register struct sigacts *ps = p->p_sigacts;
           struct uthread *ut;
           struct uthread *uth;
           thread_act_t thact;
           int error = 0;
           sigset_t mask;
           sigset_t siglist;
           sigset_t sigw=0;
           int signum;
   
           ut = (struct uthread *)get_bsdthread_info(current_act());
   
           if (uap->set == (const sigset_t *)0)
                   return(EINVAL);
   
           error = copyin((caddr_t)uap->set, (caddr_t)&mask, sizeof(sigset_t));
           if (error)
                   return(error);
   
           siglist = (mask & ~sigcantmask);
   
           if (siglist == 0)
                   return(EINVAL);
   
           signal_lock(p);
           if ((p->p_flag & P_INVFORK) && p->p_vforkact) {
                   signal_unlock(p);
                   return(EINVAL);
           } else {
                   TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) {
                           if (sigw = uth->uu_siglist & siglist) {
                                   break;
                           }
                   }
           }
           signal_unlock(p);
           if (sigw) {
                   /* The signal was pending on a thread */
                   goto sigwait1;
           }
           /*
            * When returning from sigwait, we want
            * the old mask to be restored after the
            * signal handler has finished.  Thus, we
            * save it here and mark the sigacts structure
            * to indicate this.
            */
           ut->uu_oldmask = ut->uu_sigmask;
           ut->uu_flag |= USAS_OLDMASK;
           if (siglist == (sigset_t)0)
                   return(EINVAL);
           /* SIGKILL and SIGSTOP are not maskable as well */
           ut->uu_sigmask = ~(siglist|sigcantmask);
           ut->uu_sigwait = siglist; 
           /* No Continuations for now */
           error =  tsleep((caddr_t)&ut->uu_sigwait, PPAUSE|PCATCH, "pause", 0);
   
           if ((error == EINTR) || (error == ERESTART))
                   error = 0;
   
           sigw = (ut->uu_sigwait & siglist);
           ut->uu_sigmask = ut->uu_oldmask;
           ut->uu_oldmask = 0;
           ut->uu_flag &= ~USAS_OLDMASK;
   sigwait1:
           ut->uu_sigwait = 0;
           if (!error) {
                   signum = ffs((unsigned int)sigw);
                   if (!signum)
                           panic("sigwait with no signal wakeup");
                   ut->uu_siglist &= ~(sigmask(signum));
                   if (uap->sig)
                                   error = copyout(&signum, uap->sig, sizeof(int));
           }
   
           return(error);
   
   }
   
   #if COMPAT_43
   struct osigstack_args {
           struct sigstack *nss;
           struct sigstack *oss;
   };
   
   /* ARGSUSED */
  int
  osigstack(p, uap, retval)
          struct proc *p;
          register struct osigstack_args *uap;
          register_t *retval;
  {
          struct sigstack ss;
          struct sigacts *psp;
          int error = 0;
  
          psp = p->p_sigacts;
          ss.ss_sp = psp->ps_sigstk.ss_sp;
          ss.ss_onstack = psp->ps_sigstk.ss_flags & SA_ONSTACK;
          if (uap->oss && (error = copyout((caddr_t)&ss,
              (caddr_t)uap->oss, sizeof (struct sigstack))))
                  return (error);
          if (uap->nss && (error = copyin((caddr_t)uap->nss,
              (caddr_t)&ss, sizeof (ss))) == 0) {
                  psp->ps_sigstk.ss_sp = ss.ss_sp;
                  psp->ps_sigstk.ss_size = 0;
                  psp->ps_sigstk.ss_flags |= ss.ss_onstack & SA_ONSTACK;
                  psp->ps_flags |= SAS_ALTSTACK;
          }
          return (error);
  }
  #endif /* COMPAT_43 */
  
  struct sigaltstack_args {
          struct sigaltstack *nss;
          struct sigaltstack *oss;
  };
  /* ARGSUSED */
  int
  sigaltstack(p, uap, retval)
          struct proc *p;
          register struct sigaltstack_args *uap;
          register_t *retval;
  {
          struct sigacts *psp;
          struct sigaltstack ss;
          int error;
  
          psp = p->p_sigacts;
          if ((psp->ps_flags & SAS_ALTSTACK) == 0)
                  psp->ps_sigstk.ss_flags |= SA_DISABLE;
          if (uap->oss && (error = copyout((caddr_t)&psp->ps_sigstk,
              (caddr_t)uap->oss, sizeof (struct sigaltstack))))
                  return (error);
          if (uap->nss == 0)
                  return (0);
          if (error = copyin((caddr_t)uap->nss, (caddr_t)&ss,
              sizeof (ss)))
                  return (error);
          if ((ss.ss_flags & ~SA_DISABLE) != 0)  {
                  return(EINVAL);
          }
  
          if (ss.ss_flags & SA_DISABLE) {
                  if (psp->ps_sigstk.ss_flags & SA_ONSTACK)
                          return (EINVAL);
                  psp->ps_flags &= ~SAS_ALTSTACK;
                  psp->ps_sigstk.ss_flags = ss.ss_flags;
                  return (0);
          }
  /* The older stacksize was 8K, enforce that one so no compat problems */
  #define OLDMINSIGSTKSZ 8*1024
          if (ss.ss_size < OLDMINSIGSTKSZ)
                  return (ENOMEM);
          psp->ps_flags |= SAS_ALTSTACK;
          psp->ps_sigstk= ss;
          return (0);
  }
  
  struct kill_args {
          int pid;
          int signum;
  };
  /* ARGSUSED */
  int
  kill(cp, uap, retval)
          register struct proc *cp;
          register struct kill_args *uap;
          register_t *retval;
  {
          register struct proc *p;
          register struct pcred *pc = cp->p_cred;
  
          if ((u_int)uap->signum >= NSIG)
                  return (EINVAL);
          if (uap->pid > 0) {
                  /* kill single process */
                  if ((p = pfind(uap->pid)) == NULL) {
                          if ((p = pzfind(uap->pid)) != NULL) {
                                  /*
                                   * IEEE Std 1003.1-2001: return success
                                   * when killing a zombie.
                                   */
                                  return (0);
                          }
                          return (ESRCH);
                  }
                  if (!cansignal(cp, pc, p, uap->signum))
                          return (EPERM);
                  if (uap->signum)
                          psignal(p, uap->signum);
                  return (0);
          }
          switch (uap->pid) {
          case -1:                /* broadcast signal */
                  return (killpg1(cp, uap->signum, 0, 1));
          case 0:                 /* signal own process group */
                  return (killpg1(cp, uap->signum, 0, 0));
          default:                /* negative explicit process group */
                  return (killpg1(cp, uap->signum, -(uap->pid), 0));
          }
          /* NOTREACHED */
  }
  
  #if COMPAT_43
  struct okillpg_args {
          int pgid;
          int signum;
  };
  /* ARGSUSED */
  int
  okillpg(p, uap, retval)
          struct proc *p;
          register struct okillpg_args *uap;
          register_t *retval;
  {
  
          if ((u_int)uap->signum >= NSIG)
                  return (EINVAL);
          return (killpg1(p, uap->signum, uap->pgid, 0));
  }
  #endif /* COMPAT_43 */
  
  /*
   * Common code for kill process group/broadcast kill.
   * cp is calling process.
   */
  int
  killpg1(cp, signum, pgid, all)
          register struct proc *cp;
          int signum, pgid, all;
  {
          register struct proc *p;
          register struct pcred *pc = cp->p_cred;
          struct pgrp *pgrp;
          int nfound = 0;
          
          if (all) {
                  /* 
                   * broadcast 
                   */
                  for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
                          if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || 
                              p == cp || !cansignal(cp, pc, p, signum))
                                  continue;
                          nfound++;
                          if (signum)
                                  psignal(p, signum);
                  }
          } else {
                  if (pgid == 0)          
                          /* 
                           * zero pgid means send to my process group.
                           */
                          pgrp = cp->p_pgrp;
                  else {
                          pgrp = pgfind(pgid);
                          if (pgrp == NULL)
                                  return (ESRCH);
                  }
                  for (p = pgrp->pg_members.lh_first; p != 0;
                       p = p->p_pglist.le_next) {
                          if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
                              p->p_stat == SZOMB ||
                              !cansignal(cp, pc, p, signum))
                                  continue;
                          nfound++;
                          if (signum)
                                  psignal(p, signum);
                  }
          }
          return (nfound ? 0 : ESRCH);
  }
  
  /*
   * Send a signal to a process group.
   */
  void
  gsignal(pgid, signum)
          int pgid, signum;
  {
          struct pgrp *pgrp;
  
          if (pgid && (pgrp = pgfind(pgid)))
                  pgsignal(pgrp, signum, 0);
  }
  
  /*
   * Send a signal to a process group.  If checktty is 1,
   * limit to members which have a controlling terminal.
   */
  void
  pgsignal(pgrp, signum, checkctty)
          struct pgrp *pgrp;
          int signum, checkctty;
  {
          register struct proc *p;
  
          if (pgrp)
                  for (p = pgrp->pg_members.lh_first; p != 0;
                       p = p->p_pglist.le_next)
                          if (checkctty == 0 || p->p_flag & P_CONTROLT)
                                  psignal(p, signum);
  }
  
  /*
   * Send signal to a backgrounded process blocked due to tty access
   * In FreeBSD, the backgrounded process wakes up every second and
   * discovers whether it is foregounded or not. In our case, we block 
   * the thread in tsleep as we want to avoid storm of processes as well 
   * as the suspend is only at AST level
   */
  void
  tty_pgsignal(pgrp, signum)
          struct pgrp *pgrp;
          int signum;
  {
          register struct proc *p;
  
          if (pgrp)
                  for (p = pgrp->pg_members.lh_first; p != 0;
                       p = p->p_pglist.le_next)
                          if ((p->p_flag & P_TTYSLEEP) && (p->p_flag & P_CONTROLT))
                                  psignal(p, signum);
  }
  
  /*
   * Send a signal caused by a trap to a specific thread.
   */
  void
  threadsignal(sig_actthread, signum, code)
          register thread_act_t sig_actthread;
          register int signum;
          u_long code;
  {
          register struct uthread *uth;
          register struct task * sig_task;
          register struct proc *p ;
          int mask;
  
          if ((u_int)signum >= NSIG || signum == 0)
                  return;
  
          mask = sigmask(signum);
          if ((mask & threadmask) == 0)
                  return;
          sig_task = get_threadtask(sig_actthread);
          p = (struct proc *)(get_bsdtask_info(sig_task));
  
          uth = get_bsdthread_info(sig_actthread);
          if (uth && (uth->uu_flag & P_VFORK))
                  p = uth->uu_proc;
  
          if (!(p->p_flag & P_TRACED) && (p->p_sigignore & mask))
                  return;
  
          uth->uu_siglist |= mask;
          p->p_siglist |= mask;   /* just for lame ones looking here */
          uth->uu_code = code;
          /* mark on process as well */
          signal_setast(sig_actthread);
  }
  
   
  void
  psignal(p, signum)
          register struct proc *p;
          register int signum;
  {
          psignal_lock(p, signum, 1);
  }
  
  void
  psignal_vfork(p, new_task, thr_act, signum)
          register struct proc *p;
          task_t new_task;
          thread_act_t thr_act;
          register int signum;
  {
          int withlock = 1;
          int pend = 0;
          register int s, prop;
          register sig_t action;
          int mask;
          kern_return_t kret;
          struct uthread *uth;
  
          if ((u_int)signum >= NSIG || signum == 0)
                  panic("psignal signal number");
          mask = sigmask(signum);
          prop = sigprop[signum];
  
  #if SIGNAL_DEBUG
          if(rdebug_proc && (p == rdebug_proc)) {
                  ram_printf(3);
          }
  #endif /* SIGNAL_DEBUG */
  
          if ((new_task == TASK_NULL) || (thr_act == (thread_act_t)NULL)  || is_kerneltask(new_task))
                  return;
  
  
          uth = get_bsdthread_info(thr_act);
          signal_lock(p);
  
          /*
           * proc is traced, always give parent a chance.
           */
          action = SIG_DFL;
  
          if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
                  (p->p_flag & P_TRACED) == 0)
                  p->p_nice = NZERO;
  
          if (prop & SA_CONT) {
                  p->p_siglist &= ~stopsigmask;
                  uth->uu_siglist &= ~stopsigmask;
          }
  
          if (prop & SA_STOP) {
                  /*
                   * If sending a tty stop signal to a member of an orphaned
                   * process group, discard the signal here if the action
                   * is default; don't stop the process below if sleeping,
                   * and don't clear any pending SIGCONT.
                   */
                  if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
                          action == SIG_DFL)
                          goto psigout;
                  uth->uu_siglist &= ~contsigmask;
                  p->p_siglist &= ~contsigmask;
          }
          uth->uu_siglist |= mask;
          p->p_siglist |= mask;   /* just for lame ones looking here */
          
          /* Deliver signal to the activation passed in */
          act_set_astbsd(thr_act);
  
          /*
           *      SIGKILL priority twiddling moved here from above because
           *      it needs sig_thread.  Could merge it into large switch
           *      below if we didn't care about priority for tracing
           *      as SIGKILL's action is always SIG_DFL.
           */
          if ((signum == SIGKILL) && (p->p_nice > NZERO)) {
                  p->p_nice = NZERO;
          }
  
          /*
           *      This Process is traced - wake it up (if not already
           *      stopped) so that it can discover the signal in
           *      issig() and stop for the parent.
           */
            if (p->p_flag & P_TRACED) {
                  if (p->p_stat != SSTOP)
                          goto run;
                  else
                          goto psigout;
          }
  run:
          /*
           * If we're being traced (possibly because someone attached us
           * while we were stopped), check for a signal from the debugger.
           */
          if (p->p_stat == SSTOP) {
                  if ((p->p_flag & P_TRACED) != 0 && p->p_xstat != 0) {
                          uth->uu_siglist |= sigmask(p->p_xstat); 
                          p->p_siglist |= mask;   /* just for lame ones looking here */
                  }
          }
  
          /*
           * setrunnable(p) in BSD
           */
          p->p_stat = SRUN;
  
  psigout:
          signal_unlock(p);
  }
  
  thread_act_t
  get_signalthread(struct proc *p, int signum)
  {
          struct uthread *uth;
          thread_act_t thr_act;
          sigset_t mask = sigmask(signum);
          thread_act_t sig_thread_act;
          struct task * sig_task = p->task;
          kern_return_t kret;
          
          if ((p->p_flag & P_INVFORK) && p->p_vforkact) {
                  sig_thread_act = p->p_vforkact; 
                  kret = check_actforsig(sig_task, sig_thread_act, 1);
                  if (kret == KERN_SUCCESS) 
                          return(sig_thread_act);
                  else
                          return(THR_ACT_NULL);
          } 
  
          TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) {
                  if(((uth->uu_flag & UNO_SIGMASK)== 0) && 
                          (((uth->uu_sigmask & mask) == 0) || (uth->uu_sigwait & mask))) {
                          if (check_actforsig(p->task, uth->uu_act, 1) == KERN_SUCCESS)
                                  return(uth->uu_act);
                  }
          }
          if (get_signalact(p->task, &thr_act, 1) == KERN_SUCCESS) {
                  return(thr_act);
          }
  
          return(THR_ACT_NULL);
  }
  
  /*
   * Send the signal to the process.  If the signal has an action, the action
   * is usually performed by the target process rather than the caller; we add
   * the signal to the set of pending signals for the process.
   *
   * Exceptions:
   *   o When a stop signal is sent to a sleeping process that takes the
   *     default action, the process is stopped without awakening it.
   *   o SIGCONT restarts stopped processes (or puts them back to sleep)
   *     regardless of the signal action (eg, blocked or ignored).
   *
   * Other ignored signals are discarded immediately.
   */
  void
  psignal_lock(p, signum, withlock)
          register struct proc *p;
          register int signum;
          register int withlock;
  {
          register int s, prop;
          register sig_t action;
          thread_act_t    sig_thread_act;
          register task_t         sig_task;
          int mask;
          struct uthread *uth;
          kern_return_t kret;
          int sw_funnel = 0;
  
          if ((u_int)signum >= NSIG || signum == 0)
                  panic("psignal signal number");
          mask = sigmask(signum);
          prop = sigprop[signum];
  
  #if SIGNAL_DEBUG
          if(rdebug_proc && (p == rdebug_proc)) {
                  ram_printf(3);
          }
  #endif /* SIGNAL_DEBUG */
  
          if (thread_funnel_get() == (funnel_t *)network_flock) {
                  sw_funnel = 1;
                  thread_funnel_switch(NETWORK_FUNNEL, KERNEL_FUNNEL);
          }
          /*
           *      We will need the task pointer later.  Grab it now to
           *      check for a zombie process.  Also don't send signals
           *      to kernel internal tasks.
           */
          if (((sig_task = p->task) == TASK_NULL)  || is_kerneltask(sig_task)) {
                  if (sw_funnel)
                          thread_funnel_switch(KERNEL_FUNNEL, NETWORK_FUNNEL);
                  return;
          }
  
          s = splhigh();
          KNOTE(&p->p_klist, NOTE_SIGNAL | signum);
          splx(s);
  
          /*
           * do not send signals to the process that has the thread
           * doing a reboot(). Not doing so will mark that thread aborted
           * and can cause IO failures wich will cause data loss.
           */
          if (ISSET(p->p_flag, P_REBOOT)) {
                  if (sw_funnel)
                          thread_funnel_switch(KERNEL_FUNNEL, NETWORK_FUNNEL);
                  return;
          }
  
          if (withlock)
                  signal_lock(p);
  
          /*
           *      Deliver the signal to the first thread in the task. This
           *      allows single threaded applications which use signals to
           *      be able to be linked with multithreaded libraries.  We have
           *      an implicit reference to the current thread, but need
           *      an explicit one otherwise.  The thread reference keeps
           *      the corresponding task data structures around too.  This
           *      reference is released by thread_deallocate.
           */
          
          if (((p->p_flag & P_TRACED) == 0) && (p->p_sigignore & mask))
                  goto psigout;
  
          /* If successful return with ast set */
          sig_thread_act = get_signalthread(p, signum);
  
          if (sig_thread_act == THR_ACT_NULL) {
                  /* XXXX FIXME
                  /* if it is sigkill, may be we should
                  * inject a thread to terminate
                  */
  #if SIGNAL_DEBUG
                  ram_printf(1);
  #endif /* SIGNAL_DEBUG */
                  goto psigout;
          }
  
          uth = get_bsdthread_info(sig_thread_act);
  
          /*
           * If proc is traced, always give parent a chance.
           */
          if (p->p_flag & P_TRACED)
                  action = SIG_DFL;
          else {
                  /*
                   * If the signal is being ignored,
                   * then we forget about it immediately.
                   * (Note: we don't set SIGCONT in p_sigignore,
                   * and if it is set to SIG_IGN,
                   * action will be SIG_DFL here.)
                   */
                  if (p->p_sigignore & mask)
                          goto psigout;
                  if (uth->uu_sigwait & mask)
                          action = SIG_WAIT;
                  if (uth->uu_sigmask & mask)
                          action = SIG_HOLD;
                  else if (p->p_sigcatch & mask)
                          action = SIG_CATCH;
                  else
                          action = SIG_DFL;
          }
  
          if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
                  (p->p_flag & P_TRACED) == 0)
                  p->p_nice = NZERO;
  
          if (prop & SA_CONT) {
                  uth->uu_siglist &= ~stopsigmask;
                  p->p_siglist &= ~stopsigmask;
          }
  
          if (prop & SA_STOP) {
                  /*
                   * If sending a tty stop signal to a member of an orphaned
                   * process group, discard the signal here if the action
                   * is default; don't stop the process below if sleeping,
                   * and don't clear any pending SIGCONT.
                   */
                  if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
                          action == SIG_DFL)
                          goto psigout;
                  uth->uu_siglist &= ~contsigmask;
                  p->p_siglist &= ~contsigmask;
          }
          uth->uu_siglist |= mask;
          p->p_siglist |= mask;   /* just for lame ones looking here */
  
          
          /*
           * Defer further processing for signals which are held,
           * except that stopped processes must be continued by SIGCONT.
           */
          if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP)) {
                  goto psigout;
          }
          /*
           *      SIGKILL priority twiddling moved here from above because
           *      it needs sig_thread.  Could merge it into large switch
           *      below if we didn't care about priority for tracing
           *      as SIGKILL's action is always SIG_DFL.
           */
          if ((signum == SIGKILL) && (p->p_nice > NZERO)) {
                  p->p_nice = NZERO;
          }
  
          /*
           *      Process is traced - wake it up (if not already
           *      stopped) so that it can discover the signal in
           *      issig() and stop for the parent.
           */
          if (p->p_flag & P_TRACED) {
                  if (p->p_stat != SSTOP)
                          goto run;
                  else
                          goto psigout;
          }
  
          if (action == SIG_WAIT) {
                  uth->uu_sigwait = mask;
                  uth->uu_siglist &= ~mask;
                  p->p_siglist &= ~mask;
                  wakeup(&uth->uu_sigwait);
                  /* if it is SIGCONT resume whole process */
                  if (prop & SA_CONT)
                          (void) task_resume(sig_task);
                  goto psigout;
          }
  
          if (action != SIG_DFL) {
                  /*
                   *      User wants to catch the signal.
                   *      Wake up the thread, but don't un-suspend it
                   *      (except for SIGCONT).
                   */
                  if (prop & SA_CONT) {
                          if (p->p_flag & P_TTYSLEEP) {
                                  p->p_flag &= ~P_TTYSLEEP;
                                  wakeup(&p->p_siglist);
                          } else {
                                  (void) task_resume(sig_task);
                          }
                          p->p_stat = SRUN;
                  }
                  goto run;
          } else {
                  /*      Default action - varies */
                  if (mask & stopsigmask) {
                          /*
                           * These are the signals which by default
                           * stop a process.
                           *
                           * Don't clog system with children of init
                           * stopped from the keyboard.
                           */
                          if (!(prop & SA_STOP) && p->p_pptr == initproc) {
                                  psignal_lock(p, SIGKILL, 0);
                                  uth->uu_siglist &= ~mask;
                                  p->p_siglist &= ~mask;
                                  goto psigout;
                          }
                          
                          /*
                           *      Stop the task
                           *      if task hasn't already been stopped by
                           *      a signal.
                           */
                          uth->uu_siglist &= ~mask;
                          p->p_siglist &= ~mask;
                          if (p->p_stat != SSTOP) {
                                  p->p_xstat = signum;
                                  stop(p);
                                  if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0) {
                                          struct proc *pp = p->p_pptr;
  
                                          pp->si_pid = p->p_pid;
                                          pp->si_status = p->p_xstat;
                                          pp->si_code = CLD_STOPPED;
                                          pp->si_uid = p->p_cred->p_ruid;
                                          psignal(pp, SIGCHLD);
                                  }
                          }
                          goto psigout;
                  }
  
                  switch (signum) {
                          /*
                           * Signals ignored by default have been dealt
                           * with already, since their bits are on in
                           * p_sigignore.
                           */
  
                  case SIGKILL:
                          /*
                           * Kill signal always sets process running and
                           * unsuspends it.
                           */
                          /*
                           *      Process will be running after 'run'
                           */
                          p->p_stat = SRUN;
  
                          thread_abort(sig_thread_act);
  
                          goto psigout;
  
                  case SIGCONT:
                          /*
                           * Let the process run.  If it's sleeping on an
                           * event, it remains so.
                           */
                          if (p->p_flag & P_TTYSLEEP) {
                                  p->p_flag &= ~P_TTYSLEEP;
                                  wakeup(&p->p_siglist);
                          } else {
                                  (void) task_resume(sig_task);
                          }
                          uth->uu_siglist &= ~mask;
                          p->p_siglist &= ~mask;
                          p->p_stat = SRUN;
  
                          goto psigout;
  
                  default:
                          /*
                           * All other signals wake up the process, but don't
                           * resume it.
                           */
                          goto run;
                  }
          }
          /*NOTREACHED*/
  run:
          /*
           * If we're being traced (possibly because someone attached us
           * while we were stopped), check for a signal from the debugger.
           */
          if (p->p_stat == SSTOP) {
                  if ((p->p_flag & P_TRACED) != 0 && p->p_xstat != 0)
                          uth->uu_siglist |= sigmask(p->p_xstat); 
          } else {
                  /*
                   * setrunnable(p) in BSD and
                   * Wake up the thread if it is interruptible.
                   */
                  p->p_stat = SRUN;
                  thread_abort_safely(sig_thread_act);
          }
  psigout:
          if (withlock) 
                  signal_unlock(p);
          if (sw_funnel)
                  thread_funnel_switch(KERNEL_FUNNEL, NETWORK_FUNNEL);
  }
  
  
  /* psignal_lock(p, signum, withlock ) */
  void
  psignal_uthread(thr_act, signum)
          thread_act_t thr_act;
          int signum;
  {
          struct proc *p;
          register int s, prop;
          register sig_t action;
          thread_act_t    sig_thread_act;
          register task_t         sig_task;
          int mask;
          struct uthread *uth;
          kern_return_t kret;
          int error = 0;
  
          p = (struct proc *)get_bsdtask_info(get_threadtask(thr_act));
          if ((u_int)signum >= NSIG || signum == 0)
                  panic("Invalid signal number in psignal_uthread"); 
          mask = sigmask(signum);
          prop = sigprop[signum];
  
  #if SIGNAL_DEBUG
          if(rdebug_proc && (p == rdebug_proc)) {
                  ram_printf(3);
          }
  #endif /* SIGNAL_DEBUG */
  
          /*
           *      We will need the task pointer later.  Grab it now to
           *      check for a zombie process.  Also don't send signals
           *      to kernel internal tasks.
           */
          if (((sig_task = p->task) == TASK_NULL)  || is_kerneltask(sig_task)) {
                  return;
          }
  
          sig_thread_act = thr_act;
          /*
           * do not send signals to the process that has the thread
           * doing a reboot(). Not doing so will mark that thread aborted
           * and can cause IO failures wich will cause data loss.
           */
          if (ISSET(p->p_flag, P_REBOOT)) {
                  return;
          }
  
          signal_lock(p);
  
          /*
           *      Deliver the signal to the first thread in the task. This
           *      allows single threaded applications which use signals to
           *      be able to be linked with multithreaded libraries.  We have
           *      an implicit reference to the current thread, but need
           *      an explicit one otherwise.  The thread reference keeps
           *      the corresponding task data structures around too.  This
           *      reference is released by thread_deallocate.
           */
          
          if (((p->p_flag & P_TRACED) == 0) && (p->p_sigignore & mask))
                  goto puthout;
  
          kret = check_actforsig(sig_task, sig_thread_act, 1);
  
          if (kret != KERN_SUCCESS) {
                  error = EINVAL;
                  goto puthout;
          }
  
  
          uth = get_bsdthread_info(sig_thread_act);
  
          /*
           * If proc is traced, always give parent a chance.
           */
          if (p->p_flag & P_TRACED)
                  action = SIG_DFL;
          else {
                  /*
                   * If the signal is being ignored,
                   * then we forget about it immediately.
                   * (Note: we don't set SIGCONT in p_sigignore,
                   * and if it is set to SIG_IGN,
                   * action will be SIG_DFL here.)
                   */
                  if (p->p_sigignore & mask)
                          goto puthout;
                  if (uth->uu_sigwait & mask)
                          action = SIG_WAIT;
                  if (uth->uu_sigmask & mask)
                          action = SIG_HOLD;
                  else if (p->p_sigcatch & mask)
                          action = SIG_CATCH;
                  else
                          action = SIG_DFL;
          }
  
          if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
                  (p->p_flag & P_TRACED) == 0)
                  p->p_nice = NZERO;
  
          if (prop & SA_CONT) {
                  uth->uu_siglist &= ~stopsigmask;
                  p->p_siglist &= ~stopsigmask;
          }
  
          if (prop & SA_STOP) {
                  /*
                   * If sending a tty stop signal to a member of an orphaned
                   * process group, discard the signal here if the action
                   * is default; don't stop the process below if sleeping,
                   * and don't clear any pending SIGCONT.
                   */
                  if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
                          action == SIG_DFL)
                          goto puthout;
                  uth->uu_siglist &= ~contsigmask;
                  p->p_siglist &= ~contsigmask;
          }
          uth->uu_siglist |= mask;
          p->p_siglist |= mask;   /* just for lame ones looking here */
  
          /*
           * Defer further processing for signals which are held,
           * except that stopped processes must be continued by SIGCONT.
           */
          if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP))
                  goto puthout;
                  
          /*
           *      SIGKILL priority twiddling moved here from above because
           *      it needs sig_thread.  Could merge it into large switch
           *      below if we didn't care about priority for tracing
           *      as SIGKILL's action is always SIG_DFL.
           */
          if ((signum == SIGKILL) && (p->p_nice > NZERO)) {
                  p->p_nice = NZERO;
          }
  
          /*
           *      Process is traced - wake it up (if not already
           *      stopped) so that it can discover the signal in
           *      issig() and stop for the parent.
           */
          if (p->p_flag & P_TRACED) {
                  if (p->p_stat != SSTOP)
                          goto psurun;
                  else
                          goto puthout;
          }
  
          if (action == SIG_WAIT) {
                  uth->uu_sigwait = mask;
                  uth->uu_siglist &= ~mask;
                  p->p_siglist &= ~mask;
                  wakeup(&uth->uu_sigwait);
                  /* if it is SIGCONT resume whole process */
                  if (prop & SA_CONT)
                          (void) task_resume(sig_task);
                  goto puthout;
          }
  
          if (action != SIG_DFL) {
                  /*
                   *      User wants to catch the signal.
                   *      Wake up the thread, but don't un-suspend it
                   *      (except for SIGCONT).
                   */
                  if (prop & SA_CONT)
                          (void) task_resume(sig_task);
                  goto psurun;
          } else {
                  /*      Default action - varies */
                  if (mask & stopsigmask) {
                          /*
                           * These are the signals which by default
                           * stop a process.
                           *
                           * Don't clog system with children of init
                           * stopped from the keyboard.
                           */
                          if (!(prop & SA_STOP) && p->p_pptr == initproc) {
                                  psignal_lock(p, SIGKILL, 0);
                                  uth->uu_siglist &= ~mask;
                                  p->p_siglist &= ~mask;
                                  goto puthout;
                          }
                          
                          /*
                           *      Stop the task
                           *      if task hasn't already been stopped by
                           *      a signal.
                           */
                          uth->uu_siglist &= ~mask;
                          p->p_siglist &= ~mask;
                          if (p->p_stat != SSTOP) {
                                  p->p_xstat = signum;
                                  if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0) {
                                          struct proc *pp = p->p_pptr;
  
                                          pp->si_pid = p->p_pid;
                                          pp->si_status = p->p_xstat;
                                          pp->si_code = CLD_STOPPED;
                                          pp->si_uid = p->p_cred->p_ruid;
                                          psignal(pp, SIGCHLD);
                                  }
                                  stop(p);
                          }
                          goto puthout;
                  }
  
                  switch (signum) {
                          /*
                           * Signals ignored by default have been dealt
                           * with already, since their bits are on in
                           * p_sigignore.
                           */
  
                  case SIGKILL:
                          /*
                           * Kill signal always sets process running and
                           * unsuspends it.
                           */
                          /*
                           *      Process will be running after 'run'
                           */
                          p->p_stat = SRUN;
  
                          thread_abort(sig_thread_act);
  
                          goto puthout;
  
                  case SIGCONT:
                          /*
                           * Let the process run.  If it's sleeping on an
                           * event, it remains so.
                           */
                          if (p->p_flag & P_TTYSLEEP) {
                                  p->p_flag &= ~P_TTYSLEEP;
                                  wakeup(&p->p_siglist);
                          } else {
                                  (void) task_resume(sig_task);
                          }
                          uth->uu_siglist &= ~mask;
                          p->p_siglist &= ~mask;
                          p->p_stat = SRUN;
                          goto puthout;
  
                  default:
                          /*
                           * All other signals wake up the process, but don't
                           * resume it.
                           */
                          goto psurun;
                  }
          }
          /*NOTREACHED*/
  psurun:
          /*
           * If we're being traced (possibly because someone attached us
           * while we were stopped), check for a signal from the debugger.
           */
          if (p->p_stat == SSTOP) {
                  if ((p->p_flag & P_TRACED) != 0 && p->p_xstat != 0) {
                          uth->uu_siglist |= sigmask(p->p_xstat); 
                          p->p_siglist |= sigmask(p->p_xstat); 
                  }
          } else {
                  /*
                   * setrunnable(p) in BSD and
                   * Wake up the thread if it is interruptible.
                   */
                  p->p_stat = SRUN;
                  thread_abort_safely(sig_thread_act);
          }
  
  puthout:
                  signal_unlock(p);
  }
  
  
  __inline__ void
  sig_lock_to_exit(
          struct proc     *p)
  {
          thread_t        self = current_act();
  
          p->exit_thread = self;
          (void) task_suspend(p->task);
  }
  
  __inline__ int
  sig_try_locked(
          struct proc     *p)
  {
          thread_t        self = current_act();
  
          while (p->sigwait || p->exit_thread) {
                  if (p->exit_thread) {
                          if (p->exit_thread != self) {
                                  /*
                                   * Already exiting - no signals.
                                   */
                                  thread_abort(self);
                          }
                          return(0);
                  }
                  if(assert_wait_possible()) {
                          assert_wait((caddr_t)&p->sigwait_thread, 
                                          (THREAD_INTERRUPTIBLE));
                  }
                  signal_unlock(p);
                  thread_block(THREAD_CONTINUE_NULL);
                  signal_lock(p);
                  if (thread_should_abort(self)) {
                          /*
                           * Terminate request - clean up.
                           */
                          return -1;
                  }
          }
          return 1;
  }
  
  /*
   * If the current process has received a signal (should be caught or cause
   * termination, should interrupt current syscall), return the signal number.
   * Stop signals with default action are processed immediately, then cleared;
   * they aren't returned.  This is checked after each entry to the system for
   * a syscall or trap (though this can usually be done without calling issignal
   * by checking the pending signal masks in the CURSIG macro.) The normal call
   * sequence is
   *
   *      while (signum = CURSIG(curproc))
   *              postsig(signum);
   */
  int
  issignal(p)
          register struct proc *p;
  {
          register int signum, mask, prop, sigbits;
          task_t task = p->task;
          thread_act_t cur_act;
          int     s;
          struct uthread * ut;
          kern_return_t kret;
          struct proc *pp;
  
          cur_act = current_act();
  
  #if SIGNAL_DEBUG
          if(rdebug_proc && (p == rdebug_proc)) {
                  ram_printf(3);
          }
  #endif /* SIGNAL_DEBUG */
          signal_lock(p);
  
          /*
           * Try to grab the signal lock.
           */
          if (sig_try_locked(p) <= 0) {
                  signal_unlock(p);
                  return (0);
          }
  
          ut = get_bsdthread_info(cur_act);
          for(;;) {
                  sigbits = ut->uu_siglist  & ~ut->uu_sigmask;
  
                  if (p->p_flag & P_PPWAIT)
                          sigbits &= ~stopsigmask;
                  if (sigbits == 0) {             /* no signal to send */
                          signal_unlock(p);
                          return (0);
                  }
                  signum = ffs((long)sigbits);
                  mask = sigmask(signum);
                  prop = sigprop[signum];
  
                  /*
                   * We should see pending but ignored signals
                   * only if P_TRACED was on when they were posted.
                   */
                  if (mask & p->p_sigignore && (p->p_flag & P_TRACED) == 0) {
                          ut->uu_siglist &= ~mask;                /* take the signal! */
                          p->p_siglist &= ~mask;          /* take the signal! */
                          continue;
                  }
                  if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0)  {
                          register int    hold;
                          register task_t task;
                          /*
                           * If traced, always stop, and stay
                           * stopped until released by the debugger.
                           */
                          /* ptrace debugging */
                          p->p_xstat = signum;
                          pp = p->p_pptr;
                          if (p->p_flag & P_SIGEXC) {
                                  p->sigwait = TRUE;
                                  p->sigwait_thread = cur_act;
                                  p->p_stat = SSTOP;
                                  p->p_flag &= ~P_WAITED;
                                  ut->uu_siglist &= ~mask;        /* clear the old signal */
                                  p->p_siglist &= ~mask;  /* clear the old signal */
                                  signal_unlock(p);
                                  do_bsdexception(EXC_SOFTWARE, EXC_SOFT_SIGNAL, signum);
                                  signal_lock(p);
                          } else {
  //                              panic("Unsupportef gdb option \n");;
                                  pp->si_pid = p->p_pid;
                                  pp->si_status = p->p_xstat;
                                  pp->si_code = CLD_TRAPPED;
                                  pp->si_uid = p->p_cred->p_ruid;
                                  psignal(pp, SIGCHLD);
                                  /*
                                  *       XXX Have to really stop for debuggers;
                                  *       XXX stop() doesn't do the right thing.
                                  *       XXX Inline the task_suspend because we
                                  *       XXX have to diddle Unix state in the
                                  *       XXX middle of it.
                                  */
                                  task = p->task;
                                  task_hold(task);
                                  p->sigwait = TRUE;
                                  p->sigwait_thread = cur_act;
                                  p->p_stat = SSTOP;
                                  p->p_flag &= ~P_WAITED;
                                  ut->uu_siglist &= ~mask;        /* clear the old signal */
                                  p->p_siglist &= ~mask;  /* clear the old signal */
  
                                  wakeup((caddr_t)p->p_pptr);
                                  signal_unlock(p);
                                  assert_wait((caddr_t)&p->sigwait, (THREAD_INTERRUPTIBLE));
                                  thread_block(THREAD_CONTINUE_NULL);
                                  signal_lock(p);
                          }
  
                          p->sigwait = FALSE;
                          p->sigwait_thread = NULL;
                          wakeup((caddr_t)&p->sigwait_thread);
  
                          /*
                           * This code is to detect when gdb is killed
                           * even as the traced program is attached.
                           * pgsignal would get the SIGKILL to traced program
                           * That's what we are trying to see (I hope)
                           */
                          if (ut->uu_siglist & sigmask(SIGKILL)) {
                                  /*
                                   * Wait event may still be outstanding;
                                   * clear it, since sig_lock_to_exit will
                                   * wait.
                                   */
                                  clear_wait(current_act(), THREAD_INTERRUPTED);
                                  sig_lock_to_exit(p);
                                  /*
                                  * Since this thread will be resumed
                                  * to allow the current syscall to
                                  * be completed, must save u_qsave
                                  * before calling exit().  (Since exit()
                                  * calls closef() which can trash u_qsave.)
                                  */
                                  signal_unlock(p);
                                  exit1(p,signum, (int *)NULL);
                                  return(0);
                          }
  
                          /*
                           *      We may have to quit
                           */
                          if (thread_should_abort(current_act())) {
                                  signal_unlock(p);
                                  return(0);
                          }
                          /*
                           * If parent wants us to take the signal,
                           * then it will leave it in p->p_xstat;
                           * otherwise we just look for signals again.
                           */
                          signum = p->p_xstat;
                          if (signum == 0)
                                  continue;
                          /*
                           * Put the new signal into p_siglist.  If the
                           * signal is being masked, look for other signals.
                           */
                          mask = sigmask(signum);
                          ut->uu_siglist |= mask;
                          p->p_siglist |= mask;   /* just for lame ones looking here */
                          if (ut->uu_sigmask & mask)
                                  continue;
                  }
  
                  /*
                   * Decide whether the signal should be returned.
                   * Return the signal's number, or fall through
                   * to clear it from the pending mask.
                   */
  
                  switch ((long)p->p_sigacts->ps_sigact[signum]) {
                  
                  case (long)SIG_DFL:
                          /*
                           * Don't take default actions on system processes.
                           */
                          if (p->p_pptr->p_pid == 0) {
  #if DIAGNOSTIC
                                  /*
                                   * Are you sure you want to ignore SIGSEGV
                                   * in init? XXX
                                   */
                                  printf("Process (pid %d) got signal %d\n",
                                          p->p_pid, signum);
  #endif
                                  break;                          /* == ignore */
                          }
                          
                          /*
                           * If there is a pending stop signal to process
                           * with default action, stop here,
                           * then clear the signal.  However,
                           * if process is member of an orphaned
                           * process group, ignore tty stop signals.
                           */
                          if (prop & SA_STOP) {
                                  if (p->p_flag & P_TRACED ||
                                          (p->p_pgrp->pg_jobc == 0 &&
                                          prop & SA_TTYSTOP))
                                          break;  /* == ignore */
                                  if (p->p_stat != SSTOP) {
                                          p->p_xstat = signum;
                                          stop(p);
                                          if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0) {
                                                  pp = p->p_pptr;
                                                  pp->si_pid = p->p_pid;
                                                  pp->si_status = p->p_xstat;
                                                  pp->si_code = CLD_STOPPED;
                                                  pp->si_uid = p->p_cred->p_ruid;
                                                  psignal(pp, SIGCHLD);
                                          }
                                  }
                                  break;
                          } else if (prop & SA_IGNORE) {
                                  /*
                                   * Except for SIGCONT, shouldn't get here.
                                   * Default action is to ignore; drop it.
                                   */
                                  break;          /* == ignore */
                          } else {
                                  ut->uu_siglist &= ~mask;        /* take the signal! */
                                  p->p_siglist &= ~mask;  /* take the signal! */
                                  signal_unlock(p);
                                  return (signum);
                          }
                          /*NOTREACHED*/
  
                  case (long)SIG_IGN:
                          /*
                           * Masking above should prevent us ever trying
                           * to take action on an ignored signal other
                           * than SIGCONT, unless process is traced.
                           */
                          if ((prop & SA_CONT) == 0 &&
                                  (p->p_flag & P_TRACED) == 0)
                                  printf("issignal\n");
                          break;          /* == ignore */
  
                  default:
                          /*
                           * This signal has an action, let
                           * postsig() process it.
                           */
                          ut->uu_siglist &= ~mask;                /* take the signal! */
                          p->p_siglist &= ~mask;          /* take the signal! */
                          signal_unlock(p);
                          return (signum);
                  }
                  ut->uu_siglist &= ~mask;                /* take the signal! */
                  p->p_siglist &= ~mask;          /* take the signal! */
                  }
          /* NOTREACHED */
  }
  
  /* called from _sleep */
  int
  CURSIG(p)
      register struct proc *p;
  {
          register int signum, mask, prop, sigbits;
          task_t task = p->task;
          thread_act_t cur_act;
          int     s;
          struct uthread * ut;
          int retnum = 0;
             
  
          cur_act = current_act();
  
          ut = get_bsdthread_info(cur_act);
  
          if (ut->uu_siglist == 0)
                  return (0);
  
          if (((ut->uu_siglist & ~ut->uu_sigmask) == 0) && ((p->p_flag & P_TRACED) == 0))
                  return (0);
  
          sigbits = ut->uu_siglist & ~ut->uu_sigmask;
  
          for(;;) {
                  if (p->p_flag & P_PPWAIT)
                          sigbits &= ~stopsigmask;
                  if (sigbits == 0) {             /* no signal to send */
                          return (retnum);
                  }
  
                  signum = ffs((long)sigbits);
                  mask = sigmask(signum);
                  prop = sigprop[signum];
  
                  /*
                   * We should see pending but ignored signals
                   * only if P_TRACED was on when they were posted.
                   */
                  if (mask & p->p_sigignore && (p->p_flag & P_TRACED) == 0) {
                          continue;
                  }
                  if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) {
                          /*
                           * Put the new signal into p_siglist.  If the
                           * signal is being masked, look for other signals.
                           */
                          mask = sigmask(signum);
                          if (ut->uu_sigmask & mask)
                                  continue;
                          return(signum);
                  }
  
                  /*
                   * Decide whether the signal should be returned.
                   * Return the signal's number, or fall through
                   * to clear it from the pending mask.
                   */
  
                  switch ((long)p->p_sigacts->ps_sigact[signum]) {
                  
                  case (long)SIG_DFL:
                          /*
                           * Don't take default actions on system processes.
                           */
                          if (p->p_pptr->p_pid == 0) {
  #if DIAGNOSTIC
                                  /*
                                   * Are you sure you want to ignore SIGSEGV
                                   * in init? XXX
                                   */
                                  printf("Process (pid %d) got signal %d\n",
                                          p->p_pid, signum);
  #endif
                                  break;                          /* == ignore */
                          }
                          
                          /*
                           * If there is a pending stop signal to process
                           * with default action, stop here,
                           * then clear the signal.  However,
                           * if process is member of an orphaned
                           * process group, ignore tty stop signals.
                           */
                          if (prop & SA_STOP) {
                                  if (p->p_flag & P_TRACED ||
                                          (p->p_pgrp->pg_jobc == 0 &&
                                          prop & SA_TTYSTOP))
                                          break;  /* == ignore */
                                  retnum = signum;
                                  break;
                          } else if (prop & SA_IGNORE) {
                                  /*
                                   * Except for SIGCONT, shouldn't get here.
                                   * Default action is to ignore; drop it.
                                   */
                                  break;          /* == ignore */
                          } else {
                                  return (signum);
                          }
                          /*NOTREACHED*/
  
                  case (long)SIG_IGN:
                          /*
                           * Masking above should prevent us ever trying
                           * to take action on an ignored signal other
                           * than SIGCONT, unless process is traced.
                           */
                          if ((prop & SA_CONT) == 0 &&
                                  (p->p_flag & P_TRACED) == 0)
                                  printf("issignal\n");
                          break;          /* == ignore */
  
                  default:
                          /*
                           * This signal has an action, let
                           * postsig() process it.
                           */
                          return (signum);
                  }
                  sigbits &= ~mask;               /* take the signal! */
          }
          /* NOTREACHED */
  }
  
  /*
   * Put the argument process into the stopped state and notify the parent
   * via wakeup.  Signals are handled elsewhere.  The process must not be
   * on the run queue.
   */
  void
  stop(p)
          register struct proc *p;
  {
          p->p_stat = SSTOP;
          p->p_flag &= ~P_WAITED;
          wakeup((caddr_t)p->p_pptr);
          (void) task_suspend(p->task);   /*XXX*/
  }
  
  /*
   * Take the action for the specified signal
   * from the current set of pending signals.
   */
  void
  postsig(signum)
          register int signum;
  {
          register struct proc *p = current_proc();
          register struct sigacts *ps = p->p_sigacts;
          register sig_t action;
          u_long code;
          int mask, returnmask;
          struct uthread * ut;
  
  #if DIAGNOSTIC
          if (signum == 0)
                  panic("postsig");
          /*
           *      This must be called on master cpu
           */
          if (cpu_number() != master_cpu)
                  panic("psig not on master");
  #endif
  
          signal_lock(p);
          /*
           * Try to grab the signal lock.
           */
          if (sig_try_locked(p) <= 0) {
                  signal_unlock(p);
                  return;
          }
  
          ut = (struct uthread *)get_bsdthread_info(current_act());
          mask = sigmask(signum);
          ut->uu_siglist &= ~mask;
          p->p_siglist &= ~mask;
          action = ps->ps_sigact[signum];
  #if KTRACE
          if (KTRPOINT(p, KTR_PSIG))
                  ktrpsig(p->p_tracep,
                      signum, action, ut->uu_flag & USAS_OLDMASK ?
                      &ut->uu_oldmask : &ut->uu_sigmask, 0, -1);
  #endif
          if (action == SIG_DFL) {
                  /*
                   * Default action, where the default is to kill
                   * the process.  (Other cases were ignored above.)
                   */
                  /* called with signal_lock() held */
                  sigexit_locked(p, signum);
                  return;
                  /* NOTREACHED */
          } else {
                  /*
                   * If we get here, the signal must be caught.
                   */
  #if DIAGNOSTIC
                  if (action == SIG_IGN || (ut->uu_sigmask & mask))
                          log(LOG_WARNING,
                                  "postsig: processing masked or ignored signal\n");
  #endif
                  /*
                   * Set the new mask value and also defer further
                   * occurences of this signal.
                   *
                   * Special case: user has done a sigpause.  Here the
                   * current mask is not of interest, but rather the
                   * mask from before the sigpause is what we want
                   * restored after the signal processing is completed.
                   */
                  if (ut->uu_flag & USAS_OLDMASK) {
                          returnmask = ut->uu_oldmask;
                          ut->uu_flag &= ~USAS_OLDMASK;
                          ut->uu_oldmask = 0;
                  } else
                          returnmask = ut->uu_sigmask;
                  ut->uu_sigmask |= ps->ps_catchmask[signum];
                  if ((ps->ps_signodefer & mask) == 0)
                          ut->uu_sigmask |= mask;
                  if ((signum != SIGILL) && (signum != SIGTRAP) && (ps->ps_sigreset & mask)) {
                          if ((signum != SIGCONT) && (sigprop[signum] & SA_IGNORE))
                                  p->p_sigignore |= mask;
                          ps->ps_sigact[signum] = SIG_DFL;
                          ps->ps_siginfo &= ~mask;
                          ps->ps_signodefer &= ~mask;
                  }
  #ifdef __ppc__
                  /* Needs to disable to run in user mode */
                  if (signum == SIGFPE) {
                          thread_enable_fpe(current_act(), 0);
                  }
  #endif  /* __ppc__ */
  
                  if (ps->ps_sig != signum) {
                          code = 0;
                  } else {
                          code = ps->ps_code;
                          ps->ps_code = 0;
                  }
                  p->p_stats->p_ru.ru_nsignals++;
                  sendsig(p, action, signum, returnmask, code);
          }
          signal_unlock(p);
  }
  
  /*
   * Force the current process to exit with the specified signal, dumping core
   * if appropriate.  We bypass the normal tests for masked and caught signals,
   * allowing unrecoverable failures to terminate the process without changing
   * signal state.  Mark the accounting record with the signal termination.
   * If dumping core, save the signal number for the debugger.  Calls exit and
   * does not return.
   */
   /* called with signal lock */
  void
  sigexit_locked(p, signum)
          register struct proc *p;
          int signum;
  {
  
          sig_lock_to_exit(p);
          p->p_acflag |= AXSIG;
          if (sigprop[signum] & SA_CORE) {
                  p->p_sigacts->ps_sig = signum;
                  if (coredump(p) == 0)
                          signum |= WCOREFLAG;
          }
          signal_unlock(p);
          exit1(p, W_EXITCODE(0, signum), (int *)NULL);
          /* NOTREACHED */
  }
  
  
  static int
  filt_sigattach(struct knote *kn)
  {
          struct proc *p = current_proc();
  
          kn->kn_ptr.p_proc = p;
          kn->kn_flags |= EV_CLEAR;               /* automatically set */
  
          /* XXX lock the proc here while adding to the list? */
          KNOTE_ATTACH(&p->p_klist, kn);
  
          return (0);
  }
  
  static void
  filt_sigdetach(struct knote *kn)
  {
          struct proc *p = kn->kn_ptr.p_proc;
  
          KNOTE_DETACH(&p->p_klist, kn);
  }
  
  /*
   * signal knotes are shared with proc knotes, so we apply a mask to 
   * the hint in order to differentiate them from process hints.  This
   * could be avoided by using a signal-specific knote list, but probably
   * isn't worth the trouble.
   */
  static int
  filt_signal(struct knote *kn, long hint)
  {
  
          if (hint & NOTE_SIGNAL) {
                  hint &= ~NOTE_SIGNAL;
  
                  if (kn->kn_id == hint)
                          kn->kn_data++;
          }
          return (kn->kn_data != 0);
  }
  
  void
  bsd_ast(thread_act_t thr_act)
  {
          struct proc *p = current_proc();
          struct uthread *ut = get_bsdthread_info(thr_act);
          int     signum;
          unsigned int pc;
          boolean_t funnel_state;
          static bsd_init_done = 0;
  
          if (p == NULL)
                  return;
  
          funnel_state = thread_funnel_set(kernel_flock, TRUE);
  
          if ((p->p_flag & P_OWEUPC) && (p->p_flag & P_PROFIL)) {
                  pc = get_useraddr();
                  addupc_task(p, pc, 1);
                  p->p_flag &= ~P_OWEUPC;
          }
  
          if (CHECK_SIGNALS(p, current_act(), ut)) {
                  while (signum = issignal(p))
                          postsig(signum);
          }
          if (!bsd_init_done) {
                  extern void     bsdinit_task(void);
  
                  bsd_init_done = 1;
                  bsdinit_task();
          }
  
          (void) thread_funnel_set(kernel_flock, FALSE);
  }
  
  /*
   * Follwing routines are called using callout from bsd_hardclock
   * so that psignals are called in a thread context and are funneled
   */
  void
  psignal_vtalarm(struct proc *p)
  {
          boolean_t funnel_state;
  
          if (p == NULL)
                  return;
          funnel_state = thread_funnel_set(kernel_flock, TRUE);
          psignal_lock(p, SIGVTALRM, 1);
          (void) thread_funnel_set(kernel_flock, FALSE);
  }
  
  void
  psignal_xcpu(struct proc *p)
  {
          boolean_t funnel_state;
  
          if (p == NULL)
                  return;
          funnel_state = thread_funnel_set(kernel_flock, TRUE);
          psignal_lock(p, SIGXCPU, 1);
          (void) thread_funnel_set(kernel_flock, FALSE);
  }
  
  void
  psignal_sigprof(struct proc *p)
  {
          boolean_t funnel_state;
  
          if (p == NULL)
                  return;
          funnel_state = thread_funnel_set(kernel_flock, TRUE);
          psignal_lock(p, SIGPROF, 1);
          (void) thread_funnel_set(kernel_flock, FALSE);
  }
  
  /* ptrace set runnalbe */
  void
  pt_setrunnable(struct proc *p)
  {
  task_t task;
  
          task = p->task;
  
          if (p->p_flag & P_TRACED) {
                  p->p_stat = SRUN;
                  if (p->sigwait) {
                          wakeup((caddr_t)&(p->sigwait));
                          task_release(task);
                  }
          }
  }
  
  kern_return_t
  do_bsdexception(
              int exc,
              int code,
              int sub)
  {
          exception_data_type_t   codes[EXCEPTION_CODE_MAX];
          extern kern_return_t bsd_exception(int, exception_data_type_t codes[], int);
  
          codes[0] = code;        
          codes[1] = sub;
          return(bsd_exception(exc, codes, 2));
  }
  

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