xnu-792.12.6.tar.gz

[apple/xnu.git] / bsd / kern / kern_sig.c

/*
 * Copyright (c) 2000-2001 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
 * 
 * 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.  The rights granted to you under the 
 * License may not be used to create, or enable the creation or 
 * redistribution of, unlawful or unlicensed copies of an Apple operating 
 * system, or to circumvent, violate, or enable the circumvention or 
 * violation of, any terms of an Apple operating system software license 
 * agreement.
 *
 * 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_OSREFERENCE_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/proc_internal.h>
#include <sys/kauth.h>
#include <sys/systm.h>
#include <sys/timeb.h>
#include <sys/times.h>
#include <sys/acct.h>
#include <sys/file_internal.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 <sys/sysproto.h>

#include <bsm/audit_kernel.h>

#include <machine/spl.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/lock.h>
#include <kern/task.h>          /* extern void   *get_bsdtask_info(task_t); */
#include <kern/thread.h>
#include <kern/sched_prim.h>
#include <kern/thread_call.h>
#include <mach/exception.h>
#include <mach/task.h>
#include <mach/thread_act.h>

/*
 * Missing prototypes that Mach should export
 *
 * +++
 */
extern int thread_enable_fpe(thread_t act, int onoff);
extern void unix_syscall_return(int error);
extern thread_t port_name_to_thread(mach_port_name_t port_name);
extern kern_return_t check_actforsig(task_t task, thread_t thread, int setast);
extern kern_return_t get_signalact(task_t , thread_t *, int);
extern boolean_t thread_should_abort(thread_t);
extern unsigned int get_useraddr(void);

/*
 * ---
 */

extern void doexception(int exc, int code, int sub);

void stop(struct proc *p);
int cansignal(struct proc *, kauth_cred_t, struct proc *, int);
int killpg1(struct proc *, int, int, int);
void sigexit_locked(struct proc *, int);
int setsigvec(struct proc *, int, struct __user_sigaction *);
void exit1(struct proc *, int, int *);
void psignal_uthread(thread_t, int);
kern_return_t do_bsdexception(int, int, int);
void __posix_sem_syscall_return(kern_return_t);

/* implementations in osfmk/kern/sync_sema.c. We do not want port.h in this scope, so void * them  */
kern_return_t semaphore_timedwait_signal_trap_internal(void *, void *,time_t, int32_t, void (*)(int));
kern_return_t semaphore_timedwait_trap_internal(void *, time_t, int32_t, void (*)(int));
kern_return_t semaphore_wait_signal_trap_internal(void *, void *, void (*)(int));
kern_return_t semaphore_wait_trap_internal(void *, void (*)(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 };


/*
 * NOTE: Source and target may *NOT* overlap! (target is smaller)
 */
static void
sigaltstack_64to32(struct user_sigaltstack *in, struct sigaltstack *out)
{
        out->ss_sp      = CAST_DOWN(void *,in->ss_sp);
        out->ss_size    = in->ss_size;
        out->ss_flags   = in->ss_flags;
}

/*
 * NOTE: Source and target may are permitted to overlap! (source is smaller);
 * this works because we copy fields in order from the end of the struct to
 * the beginning.
 */
static void
sigaltstack_32to64(struct sigaltstack *in, struct user_sigaltstack *out)
{
        out->ss_flags   = in->ss_flags;
        out->ss_size    = in->ss_size;
        out->ss_sp      = CAST_USER_ADDR_T(in->ss_sp);
}

static void
sigaction_64to32(struct user_sigaction *in, struct sigaction *out)
{
        /* This assumes 32 bit __sa_handler is of type sig_t */
        out->__sigaction_u.__sa_handler = CAST_DOWN(sig_t,in->__sigaction_u.__sa_handler);
        out->sa_mask = in->sa_mask;
        out->sa_flags = in->sa_flags;
}

static void
__sigaction_32to64(struct __sigaction *in, struct __user_sigaction *out)
{
        out->__sigaction_u.__sa_handler = CAST_USER_ADDR_T(in->__sigaction_u.__sa_handler);
        out->sa_tramp = CAST_USER_ADDR_T(in->sa_tramp);
        out->sa_mask = in->sa_mask;
        out->sa_flags = in->sa_flags;
}


#if SIGNAL_DEBUG
void ram_printf(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:
        error = lockmgr((struct lock__bsd__ *)&p->signal_lock[0], LK_EXCLUSIVE, 0, (struct proc *)0);
        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((struct lock__bsd__ *)&p->signal_lock[0], LK_RELEASE, (simple_lock_t)0, (struct proc *)0));
}

void
signal_setast(sig_actthread)
thread_t sig_actthread;
{
        act_set_astbsd(sig_actthread);
}

/*
 * Can process p, with ucred uc, send the signal signum to process q?
 */
int
cansignal(p, uc, q, signum)
        struct proc *p;
        kauth_cred_t uc;
        struct proc *q;
        int signum;
{
        /* you can signal yourself */
        if (p == q)
                return(1);

        if (!suser(uc, NULL))
                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 (uc->cr_ruid == q->p_ucred->cr_ruid ||
                            kauth_cred_getuid(uc) == q->p_ucred->cr_ruid ||
                            uc->cr_ruid == kauth_cred_getuid(q->p_ucred) ||
                            kauth_cred_getuid(uc) == kauth_cred_getuid(q->p_ucred))
                                return (1);
                }
                return (0);
        }

        /* XXX
         * because the P_SUGID test exists, this has extra tests which
         * could be removed.
         */
        if (uc->cr_ruid == q->p_ucred->cr_ruid ||
            uc->cr_ruid == q->p_ucred->cr_svuid ||
            kauth_cred_getuid(uc) == q->p_ucred->cr_ruid ||
            kauth_cred_getuid(uc) == q->p_ucred->cr_svuid ||
            uc->cr_ruid == kauth_cred_getuid(q->p_ucred) ||
            kauth_cred_getuid(uc) == kauth_cred_getuid(q->p_ucred))
                return (1);
        return (0);
}


/* ARGSUSED */
int
sigaction(struct proc *p, register struct sigaction_args *uap, __unused register_t *retval)
{
        struct user_sigaction vec;
        struct __user_sigaction __vec;

        struct user_sigaction *sa = &vec;
        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);

        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 (IS_64BIT_PROCESS(p)) {
                        error = copyout(sa, uap->osa, sizeof(struct user_sigaction));
                } else {
                        struct sigaction vec32;
                        sigaction_64to32(sa, &vec32);
                        error = copyout(&vec32, uap->osa, sizeof(struct sigaction));
                }
                if (error)
                        return (error);
        }
        if (uap->nsa) {
                if (IS_64BIT_PROCESS(p)) {
                        error = copyin(uap->nsa, &__vec, sizeof(struct __user_sigaction));
                } else {
                        struct __sigaction __vec32;
                        error = copyin(uap->nsa, &__vec32, sizeof(struct __sigaction));
                        __sigaction_32to64(&__vec32, &__vec);
                }
                if (error)
                        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_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);
}


static int
unblock_procsigmask(struct proc *p,  int bit)
{
        struct uthread * uth;
        thread_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);
}


static int
block_procsigmask(struct proc *p,  int bit)
{
        struct uthread * uth;
        thread_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_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);
}

/* XXX should be static? */
int
setsigvec(struct proc *p, int signum, struct __user_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] = 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_thread(), 0);
                else
                        thread_enable_fpe(current_thread(), 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_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 = USER_ADDR_NULL;
        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.
 */
int
sigprocmask(register struct proc *p, struct sigprocmask_args *uap, __unused register_t *retval)
{
        int error = 0;
        sigset_t oldmask, nmask;
        user_addr_t omask = uap->omask;
        struct uthread *ut;

        ut = (struct uthread *)get_bsdthread_info(current_thread());
        oldmask  = ut->uu_sigmask;

        if (uap->mask == USER_ADDR_NULL) {
                /* just want old mask */
                goto out;
        }
        error = copyin(uap->mask, &nmask, sizeof(sigset_t));
        if (error)
                goto out;

        switch (uap->how) {
        case SIG_BLOCK:
                block_procsigmask(p, (nmask & ~sigcantmask));
                signal_setast(current_thread());
                break;

        case SIG_UNBLOCK:
                unblock_procsigmask(p, (nmask & ~sigcantmask));
                signal_setast(current_thread());
                break;

        case SIG_SETMASK:
                set_procsigmask(p, (nmask & ~sigcantmask));
                signal_setast(current_thread());
                break;
        
        default:
                error = EINVAL;
                break;
        }
out:
        if (!error && omask != USER_ADDR_NULL)
                copyout(&oldmask, omask, sizeof(sigset_t));
        return (error);
}

int
sigpending(__unused struct proc *p, register struct sigpending_args *uap, __unused register_t *retval)
{
        struct uthread *ut;
        sigset_t pendlist;

        ut = (struct uthread *)get_bsdthread_info(current_thread());
        pendlist = ut->uu_siglist;

        if (uap->osv)
                copyout(&pendlist, uap->osv, sizeof(sigset_t));
        return(0);
}


/*
 * 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.
 */

static int
sigcontinue(__unused int error)
{
//      struct uthread *ut = get_bsdthread_info(current_thread());
  unix_syscall_return(EINTR);
}

int
sigsuspend(register struct proc *p, struct sigsuspend_args *uap, __unused register_t *retval)
{
        struct uthread *ut;

        ut = (struct uthread *)get_bsdthread_info(current_thread());

        /*
         * 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 |= UT_SAS_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);
}


int
__disable_threadsignal(struct proc *p, 
                                           __unused register struct __disable_threadsignal_args *uap, 
                                           __unused register_t *retval)
{
        struct uthread *uth;

        uth = (struct uthread *)get_bsdthread_info(current_thread());

        /* No longer valid to have any signal delivered */
        signal_lock(p);
        uth->uu_flag |= UT_NO_SIGMASK;
        signal_unlock(p);

        return(0);

}


int
__pthread_markcancel(p, uap, retval)
        struct proc *p;
        register struct __pthread_markcancel_args *uap;
        register_t *retval;
{
        thread_act_t target_act;
        int error = 0;
        struct uthread *uth;

        target_act = (thread_act_t)port_name_to_thread(uap->thread_port);

        if (target_act == THR_ACT_NULL)
                return (ESRCH);

        uth = (struct uthread *)get_bsdthread_info(target_act);

        /* if the thread is in vfork do not cancel */
        if ((uth->uu_flag & (P_VFORK | UT_CANCEL | UT_CANCELED )) == 0) {
                uth->uu_flag |= (UT_CANCEL | UT_NO_SIGMASK);
                if (((uth->uu_flag & UT_NOTCANCELPT) == 0) 
                        && ((uth->uu_flag & UT_CANCELDISABLE) == 0))
                                thread_abort_safely(target_act);
        }

        thread_deallocate(target_act);
        return (error);
}

/* if action =0 ; return the cancellation state , 
 *      if marked for cancellation, make the thread canceled
 * if action = 1 ; Enable the cancel handling
 * if action = 2; Disable the cancel handling
 */
int
__pthread_canceled(p, uap, retval)
        struct proc *p;
        register struct __pthread_canceled_args *uap;
        register_t *retval;
{
        thread_act_t thr_act;
        struct uthread *uth;
        int action = uap->action;

        thr_act = current_act();
        uth = (struct uthread *)get_bsdthread_info(thr_act);

        switch (action) {
                case 1:
                        uth->uu_flag &= ~UT_CANCELDISABLE;
                        return(0);
                case 2:
                        uth->uu_flag |= UT_CANCELDISABLE;
                        return(0);
                case 0:
                default:
                        /* if the thread is in vfork do not cancel */
                        if((uth->uu_flag & ( UT_CANCELDISABLE | UT_CANCEL | UT_CANCELED)) == UT_CANCEL) {
                                uth->uu_flag &= ~UT_CANCEL;
                                uth->uu_flag |= (UT_CANCELED | UT_NO_SIGMASK);
                                return(0);
                        }
                        return(EINVAL);
        }               
        return(EINVAL);
}

void
__posix_sem_syscall_return(kern_return_t kern_result) 
{
        int error = 0;

        if (kern_result == KERN_SUCCESS)
                error = 0;
        else if (kern_result == KERN_ABORTED)
                error = EINTR;
        else if (kern_result == KERN_OPERATION_TIMED_OUT) 
                error = ETIMEDOUT;
        else
                error = EINVAL;
        unix_syscall_return(error);
        /* does not return */
}


int
__semwait_signal(p, uap, retval)
        struct proc *p;
        register struct __semwait_signal_args *uap;
        register_t *retval;
{

        kern_return_t kern_result;
        mach_timespec_t then;
        struct timespec now;

        if(uap->timeout) {

                if (uap->relative) {
                        then.tv_sec = uap->tv_sec;
                        then.tv_nsec = uap->tv_nsec;
                } else {
                        nanotime(&now);
                        then.tv_sec = uap->tv_sec - now.tv_sec;
                        then.tv_nsec = uap->tv_nsec - now.tv_nsec;
                        if (then.tv_nsec < 0) {
                                then.tv_nsec += NSEC_PER_SEC;
                                then.tv_sec--; 
                        }
                }

                if (uap->mutex_sem == (void *)NULL)
                        kern_result = semaphore_timedwait_trap_internal(uap->cond_sem, then.tv_sec, then.tv_nsec, __posix_sem_syscall_return);
                else
                        kern_result = semaphore_timedwait_signal_trap_internal(uap->cond_sem, uap->mutex_sem, then.tv_sec, then.tv_nsec, __posix_sem_syscall_return);

        } else {

                if (uap->mutex_sem == (void *)NULL)
                        kern_result = semaphore_wait_trap_internal(uap->cond_sem, __posix_sem_syscall_return);
                else

                        kern_result = semaphore_wait_signal_trap_internal(uap->cond_sem, uap->mutex_sem, __posix_sem_syscall_return);
        }

out:
        if (kern_result == KERN_SUCCESS)
                return(0);
        else if (kern_result == KERN_ABORTED)
                return(EINTR);
        else if (kern_result == KERN_OPERATION_TIMED_OUT) 
                return(ETIMEDOUT);
        else
                return(EINVAL);
}


int 
__pthread_kill(__unused struct proc *p, 
                           register struct __pthread_kill_args *uap, 
                           __unused register_t *retval) 
{
        thread_t target_act;
        int error = 0;
        int signum = uap->sig;
        struct uthread *uth;

        target_act = (thread_t)port_name_to_thread(uap->thread_port);

        if (target_act == THREAD_NULL)
                return (ESRCH);
        if ((u_int)signum >= NSIG) {
                error = EINVAL;
                goto out;
        }

        uth = (struct uthread *)get_bsdthread_info(target_act);

        if (uth->uu_flag & UT_NO_SIGMASK) {
                error = ESRCH;
                goto out;
        }

        if (signum)
                psignal_uthread(target_act, signum);
out:
        thread_deallocate(target_act);
        return (error);
}


int 
pthread_sigmask(__unused register struct proc *p, 
                                register struct pthread_sigmask_args *uap, 
                                __unused register_t *retval)
{
        user_addr_t set = uap->set;
        user_addr_t oset = uap->oset;
        sigset_t nset;
        int error = 0;
        struct uthread *ut;
        sigset_t  oldset;

        ut = (struct uthread *)get_bsdthread_info(current_thread());
        oldset = ut->uu_sigmask;

        if (set == USER_ADDR_NULL) {
                /* need only old mask */
                goto out;
        }

        error = copyin(set, &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_thread());
                break;

        case SIG_SETMASK:
                ut->uu_sigmask = (nset & ~sigcantmask);
                signal_setast(current_thread());
                break;
        
        default:
                error = EINVAL;

        }
out:
        if (!error && oset != USER_ADDR_NULL)
                copyout(&oldset, oset, sizeof(sigset_t));

        return(error);
}


int 
sigwait(register struct proc *p, register struct sigwait_args *uap, __unused register_t *retval)
{
        struct uthread *ut;
        struct uthread *uth;
        int error = 0;
        sigset_t mask;
        sigset_t siglist;
        sigset_t sigw=0;
        int signum;

        ut = (struct uthread *)get_bsdthread_info(current_thread());

        if (uap->set == USER_ADDR_NULL)
                return(EINVAL);

        error = copyin(uap->set, &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 |= UT_SAS_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 &= ~UT_SAS_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 != USER_ADDR_NULL)
                                error = copyout(&signum, uap->sig, sizeof(int));
        }

        return(error);

}


int
sigaltstack(struct proc *p, register struct sigaltstack_args *uap, __unused register_t *retval)
{
        struct sigacts *psp;
        struct user_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) {
                if (IS_64BIT_PROCESS(p)) {
                        error = copyout(&psp->ps_sigstk, uap->oss, sizeof(struct user_sigaltstack));
                } else {
                        struct sigaltstack ss32;
                        sigaltstack_64to32(&psp->ps_sigstk, &ss32);
                        error = copyout(&ss32, uap->oss, sizeof(struct sigaltstack));
                }
                if (error)
                        return (error);
        }
        if (uap->nss == USER_ADDR_NULL)
                return (0);
        if (IS_64BIT_PROCESS(p)) {
                error = copyin(uap->nss, &ss, sizeof(struct user_sigaltstack));
        } else {
                struct sigaltstack ss32;
                error = copyin(uap->nss, &ss32, sizeof(struct sigaltstack));
                sigaltstack_32to64(&ss32,&ss);
        }
        if (error)
                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);
}

int
kill(struct proc *cp, struct kill_args *uap, __unused register_t *retval)
{
        register struct proc *p;
        kauth_cred_t uc = kauth_cred_get();

       AUDIT_ARG(pid, uap->pid);
       AUDIT_ARG(signum, uap->signum);

        if ((u_int)uap->signum >= NSIG)
                return (EINVAL);
        if (uap->pid > 0) {
                /* kill single process */
                if ((p = proc_findref(uap->pid)) == NULL) {
                        if ((p = pzfind(uap->pid)) != NULL) {
                                /*
                                 * IEEE Std 1003.1-2001: return success
                                 * when killing a zombie.
                                 */
                                return (0);
                        }
                        return (ESRCH);
                }
                AUDIT_ARG(process, p);
                if (!cansignal(cp, uc, p, uap->signum)) {
                        proc_dropref(p);
                        return(EPERM);
                }
                if (uap->signum)
                        psignal(p, uap->signum);
                proc_dropref(p);
                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 */
}


/*
 * 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;
        kauth_cred_t uc = cp->p_ucred;
        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, uc, 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, uc, 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(thread_t sig_actthread, 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 & UT_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(struct proc *p, task_t new_task, thread_t thr_act, int signum)
{
        register int prop;
        register sig_t action;
        int mask;
        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_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);
}

static thread_t
get_signalthread(struct proc *p, int signum)
{
        struct uthread *uth;
        thread_t thr_act;
        sigset_t mask = sigmask(signum);
        thread_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(THREAD_NULL);
        } 

        TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) {
                if(((uth->uu_flag & UT_NO_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(THREAD_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_t        sig_thread_act;
        register task_t         sig_task;
        int mask;
        struct uthread *uth;
        boolean_t funnel_state = FALSE;
        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 *)0) {
                sw_funnel = 1;
                funnel_state = thread_funnel_set(kernel_flock, TRUE);
        }
        /*
         *      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_set(kernel_flock, funnel_state);
                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_set(kernel_flock, funnel_state);
                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 == THREAD_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;
                /* sigwait takes precedence */
                if (uth->uu_sigwait & mask)
                        action = KERN_SIG_WAIT;
                else if (uth->uu_sigmask & mask)
                        action = KERN_SIG_HOLD;
                else if (p->p_sigcatch & mask)
                        action = KERN_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 == KERN_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 == KERN_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) {
                        p->p_flag |= P_CONTINUED;
                        (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 {
                                p->p_flag |= P_CONTINUED;
                                (void) task_resume(sig_task);
                        }
                        p->p_stat = SRUN;
                } else if (p->p_stat == SSTOP)
                        goto psigout;
                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_ucred->cr_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 {
                                p->p_flag |= P_CONTINUED;
                                (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.
                         */
                        if (p->p_stat == SSTOP)
                                goto psigout;
                        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_set(kernel_flock, funnel_state);
}


/* psignal_lock(p, signum, withlock ) */
void
psignal_uthread(thr_act, signum)
        thread_t thr_act;
        int signum;
{
        struct proc *p;
        register int prop;
        register sig_t action;
        thread_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;
                /* sigwait takes precedence */
                if (uth->uu_sigwait & mask)
                        action = KERN_SIG_WAIT;
                else if (uth->uu_sigmask & mask)
                        action = KERN_SIG_HOLD;
                else if (p->p_sigcatch & mask)
                        action = KERN_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 == KERN_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 == KERN_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) {
                        p->p_flag |= P_CONTINUED;
                        (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) {
                        p->p_flag |= P_CONTINUED;
                        (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_ucred->cr_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 {
                                p->p_flag |= P_CONTINUED;
                                (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_thread();

        p->exit_thread = self;
        (void) task_suspend(p->task);
}

__inline__ int
sig_try_locked(struct proc *p)
{
        thread_t        self = current_thread();

        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;
        thread_t cur_act;
        struct uthread * ut;
        struct proc *pp;

        cur_act = current_thread();

#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 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|P_CONTINUED);
                                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_ucred->cr_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|P_CONTINUED);
                                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_thread(), 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_thread())) {
                                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_ucred->cr_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;
        thread_t cur_act;
        struct uthread * ut;
        int retnum = 0;
           

        cur_act = current_thread();

        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|P_CONTINUED);
        if (p->p_pptr->p_stat != SSTOP)
                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(int signum)
{
        struct proc *p = current_proc();
        struct sigacts *ps = p->p_sigacts;
        user_addr_t catcher;
        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_thread());
        mask = sigmask(signum);
        ut->uu_siglist &= ~mask;
        p->p_siglist &= ~mask;
        catcher = ps->ps_sigact[signum];
#if KTRACE
        //LP64: catcher argument is a 64 bit user space handler address
        if (KTRPOINT(p, KTR_PSIG))
                ktrpsig(p->p_tracep,
                    signum, CAST_DOWN(void *,catcher), ut->uu_flag & UT_SAS_OLDMASK ?
                    &ut->uu_oldmask : &ut->uu_sigmask, 0);
#endif
        if (catcher == SIG_DFL) {
                /*
                 * Default catcher, 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 (catcher == 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 & UT_SAS_OLDMASK) {
                        returnmask = ut->uu_oldmask;
                        ut->uu_flag &= ~UT_SAS_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_thread(), 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, catcher, 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;
                signal_unlock(p);
                if (coredump(p) == 0)
                        signum |= WCOREFLAG;
        } else 
                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 == (unsigned int)hint)
                        kn->kn_data++;
        }
        return (kn->kn_data != 0);
}


void
bsd_ast(thread_t thr_act)
{
        struct proc *p = current_proc();
        struct uthread *ut = get_bsdthread_info(thr_act);
        int     signum;
        user_addr_t pc;
        boolean_t funnel_state;
        static int 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_thread(), ut)) {
                while ( (signum = issignal(p)) )
                        postsig(signum);
        }
        if (!bsd_init_done) {
                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];

        codes[0] = code;        
        codes[1] = sub;
        return(bsd_exception(exc, codes, 2));
}

int
proc_pendingsignals(struct proc *p, sigset_t mask)
{
        struct uthread * uth;
        thread_t th;
        sigset_t bits = 0;
        int error;

        /* If the process is in proc exit return no signal info */
        if (p->p_lflag & P_LPEXIT) 
                return(0);

        /* duplicate the signal lock code to enable recursion; as exit
         * holds the lock too long. All this code is being reworked
         * this is just a workaround for regressions till new code
         * arrives.
         */
ppend_retry:
                error = lockmgr((struct lock__bsd__ *)&p->signal_lock[0], (LK_EXCLUSIVE | LK_CANRECURSE), 0, (struct proc *)0);
                if (error == EINTR)
                        goto ppend_retry;

        if ((p->p_flag & P_INVFORK) && p->p_vforkact) {
                th = p->p_vforkact;     
                uth = (struct uthread *)get_bsdthread_info(th);
                if (uth) {
                        bits = (((uth->uu_siglist & ~uth->uu_sigmask) & ~p->p_sigignore) & mask);
                }
                goto out;
        } 

        bits = 0;
        TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) {
                bits |= (((uth->uu_siglist & ~uth->uu_sigmask) & ~p->p_sigignore) & mask);
        }
out:
        signal_unlock(p);
        return(bits);
}

int
thread_issignal(proc_t p, thread_t th, sigset_t mask)
{
        struct uthread * uth;
        sigset_t  bits=0;


                uth = (struct uthread *)get_bsdthread_info(th);
                if (uth) {
                        bits = (((uth->uu_siglist & ~uth->uu_sigmask) & ~p->p_sigignore) & mask);
                }
                return(bits);
}