xnu-201.19.3.tar.gz

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

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This 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 OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995-1998 Apple Computer, Inc. All Rights Reserved */
/*
 * Copyright (c) 1982, 1986, 1989, 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)kern_sig.c  8.7 (Berkeley) 4/18/94
 */

#define SIGPROP         /* include signal properties table */
#include <sys/param.h>
#include <sys/signalvar.h>
#include <sys/resourcevar.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/timeb.h>
#include <sys/times.h>
#include <sys/buf.h>
#include <sys/acct.h>
#include <sys/file.h>
#include <sys/kernel.h>
#include <sys/wait.h>
#include <sys/ktrace.h>
#include <sys/syslog.h>
#include <sys/stat.h>
#include <sys/lock.h>

#include <sys/mount.h>

#include <kern/cpu_number.h>

#include <sys/vm.h>
#include <sys/user.h>           /* for coredump */
#include <kern/ast.h>           /* for APC support */
#include <kern/thread.h>
#include <kern/thread_call.h>

void stop __P((struct proc *p));
int cansignal __P((struct proc *, struct pcred *, struct proc *, int));
int killpg1 __P((struct proc *, int, int, int));
void sigexit_locked __P((struct proc *, int));
void setsigvec __P((struct proc *, int, struct sigaction *));
void exit1 __P((struct proc *, int, int *));
int signal_lock __P((struct proc *));
int signal_unlock __P((struct proc *));
void signal_setast __P((thread_act_t *));
void signal_clearast __P((thread_act_t *));
void psignal_lock __P((struct proc *, int, int, int));

#if SIGNAL_DEBUG
void ram_printf __P((int));
int ram_debug=0;
unsigned int rdebug_proc=0;
void
ram_printf(int x)
{
    printf("x is %d",x);

}

#endif /* SIGNAL_DEBUG */
int
signal_lock(struct proc *p)
{
int error = 0;
#if 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 */

siglock_retry:
        error = lockmgr(&p->signal_lock, LK_EXCLUSIVE, 0, (struct proc *)0);
        if (error == EINTR)
                goto siglock_retry;
        return(error);
}

int
signal_unlock(struct proc *p)
{
#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 */

        return(lockmgr(&p->signal_lock, LK_RELEASE, (simple_lock_t)0, (struct proc *)0));
}

void
signal_setast(sig_actthread)
thread_act_t *sig_actthread;
{
        thread_ast_set(sig_actthread, AST_BSD);
        if ((thread_act_t *)current_act() == sig_actthread)
            ast_on(AST_BSD);
}

void
signal_clearast(sig_actthread)
thread_act_t *sig_actthread;
{
        thread_ast_clear(sig_actthread, AST_BSD);
        if ((thread_act_t *)current_act() == sig_actthread)
            ast_off(AST_BSD);
}

/*
 * Can process p, with pcred pc, send the signal signum to process q?
 */
int
cansignal(p, pc, q, signum)
        struct proc *p;
        struct pcred *pc;
        struct proc *q;
        int signum;
{
        if (pc->pc_ucred->cr_uid == 0)
                return (1);             /* root can always signal */

        if (signum == SIGCONT && q->p_session == p->p_session)
                return (1);             /* SIGCONT in session */

        /*
         * Using kill(), only certain signals can be sent to setugid
         * child processes
         */
        if (q->p_flag & P_SUGID) {
                switch (signum) {
                case 0:
                case SIGKILL:
                case SIGINT:
                case SIGTERM:
                case SIGSTOP:
                case SIGTTIN:
                case SIGTTOU:
                case SIGTSTP:
                case SIGHUP:
                case SIGUSR1:
                case SIGUSR2:
                        if (pc->p_ruid == q->p_cred->p_ruid ||
                            pc->pc_ucred->cr_uid == q->p_cred->p_ruid ||
                            pc->p_ruid == q->p_ucred->cr_uid ||
                            pc->pc_ucred->cr_uid == q->p_ucred->cr_uid)
                                return (1);
                }
                return (0);
        }

        /* XXX
         * because the P_SUGID test exists, this has extra tests which
         * could be removed.
         */
        if (pc->p_ruid == q->p_cred->p_ruid ||
            pc->p_ruid == q->p_cred->p_svuid ||
            pc->pc_ucred->cr_uid == q->p_cred->p_ruid ||
            pc->pc_ucred->cr_uid == q->p_cred->p_svuid ||
            pc->p_ruid == q->p_ucred->cr_uid ||
            pc->pc_ucred->cr_uid == q->p_ucred->cr_uid)
                return (1);
        return (0);
}

struct sigaction_args {
        int     signum;
        struct sigaction *nsa;
        struct sigaction *osa;
};

/* ARGSUSED */
int
sigaction(p, uap, retval)
        struct proc *p;
        register struct sigaction_args *uap;
        register_t *retval;
{
        struct sigaction vec;
        register struct sigaction *sa;
        register struct sigacts *ps = p->p_sigacts;
        register int signum;
        int bit, error;

        signum = uap->signum;
        if (signum <= 0 || signum >= NSIG ||
            signum == SIGKILL || signum == SIGSTOP)
                return (EINVAL);
        sa = &vec;
        if (uap->osa) {
                sa->sa_handler = ps->ps_sigact[signum];
                sa->sa_mask = ps->ps_catchmask[signum];
                bit = sigmask(signum);
                sa->sa_flags = 0;
                if ((ps->ps_sigonstack & bit) != 0)
                        sa->sa_flags |= SA_ONSTACK;
                if ((ps->ps_sigintr & bit) == 0)
                        sa->sa_flags |= SA_RESTART;
                if (p->p_flag & P_NOCLDSTOP)
                        sa->sa_flags |= SA_NOCLDSTOP;
                if (error = copyout((caddr_t)sa, (caddr_t)uap->osa,
                    sizeof (vec)))
                        return (error);
        }
        if (uap->nsa) {
                if (error = copyin((caddr_t)uap->nsa, (caddr_t)sa,
                    sizeof (vec)))
                        return (error);
                setsigvec(p, signum, sa);
        }
        return (0);
}

static int
reset_sigbits(thread_act_t th_act, int bit) 
{
struct uthread *ut;
        ut = get_bsdthread_info(th_act);
        if (ut) {
                ut->uu_sig &= ~bit;
        }
}

int
clear_sigbits (struct proc *p,  int bit)
{
task_t task = p->task;

        p->p_siglist &= ~(bit);
        task_act_iterate_wth_args(task, reset_sigbits, bit);
        return(0);
}


void
setsigvec(p, signum, sa)
        register struct proc *p;
        int signum;
        register struct sigaction *sa;
{
        register struct sigacts *ps = p->p_sigacts;
        register int bit;

        bit = sigmask(signum);
        /*
         * Change setting atomically.
         */
        ps->ps_sigact[signum] = sa->sa_handler;
        ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask;
        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 (signum == SIGCHLD) {
                if (sa->sa_flags & SA_NOCLDSTOP)
                        p->p_flag |= P_NOCLDSTOP;
                else
                        p->p_flag &= ~P_NOCLDSTOP;
        }
        /*
         * 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)) {
                p->p_siglist &= ~bit;           /* never to be seen again */
                /*
                 *      If this is a thread signal, clean out the
                 *      threads as well.
                 */
                if (bit & threadmask) {
                        register        task_t          task = p->task;

                        task_act_iterate_wth_args(task, reset_sigbits, 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;
        }
}

/*
 * 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)
        register struct proc *p;
{
        register struct sigacts *ps = p->p_sigacts;
        register int nc, mask;

        /*
         * 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;
                        p->p_siglist &= ~mask;
                }
                ps->ps_sigact[nc] = SIG_DFL;
        }
        /*
         * Reset stack state to the user stack.
         * Clear set of signals caught on the signal stack.
         */
        ps->ps_sigstk.ss_flags = SA_DISABLE;
        ps->ps_sigstk.ss_size = 0;
        ps->ps_sigstk.ss_sp = 0;
        ps->ps_flags = 0;
}

/*
 * Manipulate signal mask.
 * Note that we receive new mask, not pointer,
 * and return old mask as return value;
 * the library stub does the rest.
 */
struct sigprocmask_args {
        int     how;
        sigset_t mask;
};
int
sigprocmask(p, uap, retval)
        register struct proc *p;
        struct sigprocmask_args *uap;
        register_t *retval;
{
        int error = 0;

        *retval = p->p_sigmask;

        switch (uap->how) {
        case SIG_BLOCK:
                p->p_sigmask |= uap->mask &~ sigcantmask;
                break;

        case SIG_UNBLOCK:
                p->p_sigmask &= ~(uap->mask);
                signal_setast(current_act());
                break;

        case SIG_SETMASK:
                p->p_sigmask = uap->mask &~ sigcantmask;
                signal_setast(current_act());
                break;
        
        default:
                error = EINVAL;
                break;
        }
        return (error);
}

/* ARGSUSED */
int
sigpending(p, uap, retval)
        struct proc *p;
        void *uap;
        register_t *retval;
{

        *retval = p->p_siglist;
        return (0);
}

#if COMPAT_43
/*
 * Generalized interface signal handler, 4.3-compatible.
 */
struct osigvec_args {
        int signum;
        struct sigvec *nsv;
        struct sigvec *osv;
};
/* ARGSUSED */
int
osigvec(p, uap, retval)
        struct proc *p;
        register struct osigvec_args *uap;
        register_t *retval;
{
        struct sigvec vec;
        register struct sigacts *ps = p->p_sigacts;
        register struct sigvec *sv;
        register int signum;
        int bit, error;

        signum = uap->signum;
        if (signum <= 0 || signum >= NSIG ||
            signum == SIGKILL || signum == SIGSTOP)
                return (EINVAL);
        sv = &vec;
        if (uap->osv) {
                *(sig_t *)&sv->sv_handler = ps->ps_sigact[signum];
                sv->sv_mask = ps->ps_catchmask[signum];
                bit = sigmask(signum);
                sv->sv_flags = 0;
                if ((ps->ps_sigonstack & bit) != 0)
                        sv->sv_flags |= SV_ONSTACK;
                if ((ps->ps_sigintr & bit) != 0)
                        sv->sv_flags |= SV_INTERRUPT;
                        if (p->p_flag & P_NOCLDSTOP)
                                sv->sv_flags |= SA_NOCLDSTOP;
                if (error = copyout((caddr_t)sv, (caddr_t)uap->osv,
                    sizeof (vec)))
                        return (error);
        }
        if (uap->nsv) {
                if (error = copyin((caddr_t)uap->nsv, (caddr_t)sv,
                    sizeof (vec)))
                        return (error);
                sv->sv_flags ^= SA_RESTART;     /* opposite of SV_INTERRUPT */
                setsigvec(p, signum, (struct sigaction *)sv);
        }
        return (0);
}

struct osigblock_args {
        int mask;
};
int
osigblock(p, uap, retval)
        register struct proc *p;
        struct osigblock_args *uap;
        register_t *retval;
{

        *retval = p->p_sigmask;
        p->p_sigmask |= uap->mask &~ sigcantmask;
        return (0);
}

struct osigsetmask_args {
        int mask;
};
int
osigsetmask(p, uap, retval)
        struct proc *p;
        struct osigsetmask_args *uap;
        register_t *retval;
{

        *retval = p->p_sigmask;
        p->p_sigmask = uap->mask &~ sigcantmask;
        return (0);
}
#endif /* COMPAT_43 */

/*
 * Suspend process until signal, providing mask to be set
 * in the meantime.  Note nonstandard calling convention:
 * libc stub passes mask, not pointer, to save a copyin.
 */

int
sigcontinue(error)
{
  unix_syscall_return(EINTR);
}

struct sigsuspend_args {
        int mask;
};

/* ARGSUSED */
int
sigsuspend(p, uap, retval)
        register struct proc *p;
        struct sigsuspend_args *uap;
        register_t *retval;
{
        register struct sigacts *ps = p->p_sigacts;

        /*
         * 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.
         */
        ps->ps_oldmask = p->p_sigmask;
        ps->ps_flags |= SAS_OLDMASK;
        p->p_sigmask = uap->mask &~ sigcantmask;
        (void) tsleep0((caddr_t) p, PPAUSE|PCATCH, "pause", 0, sigcontinue);
        /* always return EINTR rather than ERESTART... */
        return (EINTR);
}

#if COMPAT_43
struct osigstack_args {
        struct sigstack *nss;
        struct sigstack *oss;
};
/* ARGSUSED */
int
osigstack(p, uap, retval)
        struct proc *p;
        register struct osigstack_args *uap;
        register_t *retval;
{
        struct sigstack ss;
        struct sigacts *psp;
        int error = 0;

        psp = p->p_sigacts;
        ss.ss_sp = psp->ps_sigstk.ss_sp;
        ss.ss_onstack = psp->ps_sigstk.ss_flags & SA_ONSTACK;
        if (uap->oss && (error = copyout((caddr_t)&ss,
            (caddr_t)uap->oss, sizeof (struct sigstack))))
                return (error);
        if (uap->nss && (error = copyin((caddr_t)uap->nss,
            (caddr_t)&ss, sizeof (ss))) == 0) {
                psp->ps_sigstk.ss_sp = ss.ss_sp;
                psp->ps_sigstk.ss_size = 0;
                psp->ps_sigstk.ss_flags |= ss.ss_onstack & SA_ONSTACK;
                psp->ps_flags |= SAS_ALTSTACK;
        }
        return (error);
}
#endif /* COMPAT_43 */

struct sigaltstack_args {
        struct sigaltstack *nss;
        struct sigaltstack *oss;
};
/* ARGSUSED */
int
sigaltstack(p, uap, retval)
        struct proc *p;
        register struct sigaltstack_args *uap;
        register_t *retval;
{
        struct sigacts *psp;
        struct sigaltstack ss;
        int error;

        psp = p->p_sigacts;
        if ((psp->ps_flags & SAS_ALTSTACK) == 0)
                psp->ps_sigstk.ss_flags |= SA_DISABLE;
        if (uap->oss && (error = copyout((caddr_t)&psp->ps_sigstk,
            (caddr_t)uap->oss, sizeof (struct sigaltstack))))
                return (error);
        if (uap->nss == 0)
                return (0);
        if (error = copyin((caddr_t)uap->nss, (caddr_t)&ss,
            sizeof (ss)))
                return (error);
        if (ss.ss_flags & SA_DISABLE) {
                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);
        }
        if (ss.ss_size < MINSIGSTKSZ)
                return (ENOMEM);
        psp->ps_flags |= SAS_ALTSTACK;
        psp->ps_sigstk= ss;
        return (0);
}

struct kill_args {
        int pid;
        int signum;
};
/* ARGSUSED */
int
kill(cp, uap, retval)
        register struct proc *cp;
        register struct kill_args *uap;
        register_t *retval;
{
        register struct proc *p;
        register struct pcred *pc = cp->p_cred;

        if ((u_int)uap->signum >= NSIG)
                return (EINVAL);
        if (uap->pid > 0) {
                /* kill single process */
                if ((p = pfind(uap->pid)) == NULL)
                        return (ESRCH);
                if (!cansignal(cp, pc, p, uap->signum))
                        return (EPERM);
                if (uap->signum)
                        psignal(p, uap->signum);
                return (0);
        }
        switch (uap->pid) {
        case -1:                /* broadcast signal */
                return (killpg1(cp, uap->signum, 0, 1));
        case 0:                 /* signal own process group */
                return (killpg1(cp, uap->signum, 0, 0));
        default:                /* negative explicit process group */
                return (killpg1(cp, uap->signum, -(uap->pid), 0));
        }
        /* NOTREACHED */
}

#if COMPAT_43
struct okillpg_args {
        int pgid;
        int signum;
};
/* ARGSUSED */
int
okillpg(p, uap, retval)
        struct proc *p;
        register struct okillpg_args *uap;
        register_t *retval;
{

        if ((u_int)uap->signum >= NSIG)
                return (EINVAL);
        return (killpg1(p, uap->signum, uap->pgid, 0));
}
#endif /* COMPAT_43 */

/*
 * Common code for kill process group/broadcast kill.
 * cp is calling process.
 */
int
killpg1(cp, signum, pgid, all)
        register struct proc *cp;
        int signum, pgid, all;
{
        register struct proc *p;
        register struct pcred *pc = cp->p_cred;
        struct pgrp *pgrp;
        int nfound = 0;
        
        if (all) {
                /* 
                 * broadcast 
                 */
                for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
                        if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || 
                            p == cp || !cansignal(cp, pc, p, signum))
                                continue;
                        nfound++;
                        if (signum)
                                psignal(p, signum);
                }
        } else {
                if (pgid == 0)          
                        /* 
                         * zero pgid means send to my process group.
                         */
                        pgrp = cp->p_pgrp;
                else {
                        pgrp = pgfind(pgid);
                        if (pgrp == NULL)
                                return (ESRCH);
                }
                for (p = pgrp->pg_members.lh_first; p != 0;
                     p = p->p_pglist.le_next) {
                        if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
                            p->p_stat == SZOMB ||
                            !cansignal(cp, pc, p, signum))
                                continue;
                        nfound++;
                        if (signum)
                                psignal(p, signum);
                }
        }
        return (nfound ? 0 : ESRCH);
}

/*
 * Send a signal to a process group.
 */
void
gsignal(pgid, signum)
        int pgid, signum;
{
        struct pgrp *pgrp;

        if (pgid && (pgrp = pgfind(pgid)))
                pgsignal(pgrp, signum, 0);
}

/*
 * Send a signal to a process group.  If checktty is 1,
 * limit to members which have a controlling terminal.
 */
void
pgsignal(pgrp, signum, checkctty)
        struct pgrp *pgrp;
        int signum, checkctty;
{
        register struct proc *p;

        if (pgrp)
                for (p = pgrp->pg_members.lh_first; p != 0;
                     p = p->p_pglist.le_next)
                        if (checkctty == 0 || p->p_flag & P_CONTROLT)
                                psignal(p, signum);
}

/*
 * Send a signal caused by a trap to a specific thread.
 */
void
threadsignal(sig_actthread, signum, code)
        register thread_act_t *sig_actthread;
        register int signum;
        u_long code;
{
        register struct uthread *uth;
        register struct task * sig_task;
        register struct proc *p ;
        int mask;

        if ((u_int)signum >= NSIG || signum == 0)
                return;

        mask = sigmask(signum);
        if ((mask & threadmask) == 0)
                return;
        sig_task = get_threadtask(sig_actthread);
        p = (struct proc *)(get_bsdtask_info(sig_task));

        uth = get_bsdthread_info(sig_actthread);
        if (uth && (uth->uu_flag & P_VFORK))
                p = uth->uu_proc;

        if (!(p->p_flag & P_TRACED) && (p->p_sigignore & mask))
                return;

        uth->uu_sig |= mask;
        uth->uu_code = code;
        /* mark on process as well */
        p->p_siglist |= mask;
        signal_setast(sig_actthread);
}

 
void
psignal_pend(p) 
        register struct proc *p;
{
        boolean_t funnel_state;
        register int sigbits, mask, signum;

        thread_funnel_set(kernel_flock, TRUE);

        if (p->p_sigpending == 0)
                        return;
        

        signal_lock(p);

        for (;;) {
                sigbits = p->p_sigpending;
                if (sigbits == 0)
                        goto out;
                signum = ffs((long)sigbits);
                mask = sigmask(signum);
                p->p_sigpending &= ~mask;

                psignal_lock(p, signum, 0, 0);

        }
out:
        p->p_flag &= ~P_SIGTHR;
        signal_unlock(p);
        thread_funnel_set(kernel_flock, FALSE);
}

void
psignal(p, signum)
        register struct proc *p;
        register int signum;
{
        psignal_lock(p, signum, 1, 1);
}


void
psignal_vfork(p, new_task, thr_act, signum)
        register struct proc *p;
        task_t new_task;
        thread_act_t thr_act;
        register int signum;
{
        int withlock = 1;
        int pend = 0;
        register int s, prop;
        register sig_t action;
        int mask;
        kern_return_t kret;

        if ((u_int)signum >= NSIG || signum == 0)
                panic("psignal signal number");
        mask = sigmask(signum);
        prop = sigprop[signum];

#if SIGNAL_DEBUG
        if(rdebug_proc && (p == rdebug_proc)) {
                ram_printf(3);
        }
#endif /* SIGNAL_DEBUG */

        if ((new_task == TASK_NULL) || (thr_act == (thread_act_t)NULL)  || is_kerneltask(new_task))
                return;


        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;

        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;
                p->p_siglist &= ~contsigmask;
        }
        p->p_siglist |= mask;
        
        /* Deliver signal to the activation passed in */
        thread_ast_set(thr_act, AST_BSD);

        /*
         *      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;
#if XXX
                /*
                 * we need to make changes here to get nice to work 
                 * reset priority to BASEPRI_USER
                 */
#endif
        }

        /*
         *      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)
                        p->p_siglist |= sigmask(p->p_xstat); 
        }

        /*
         * setrunnable(p) in BSD
         */
        p->p_stat = SRUN;

psigout:
        signal_unlock(p);
}

/*
 * 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, pend)
        register struct proc *p;
        register int signum;
        register int withlock;
        register int pend;
{
        register int s, prop;
        register sig_t action;
        thread_act_t    sig_thread_act;
        thread_t        sig_thread;
        register task_t         sig_task;
        register thread_t       cur_thread;
        thread_act_t    *cur_act;
        int mask;
        kern_return_t kret;
        int sw_funnel = 0;

        if ((u_int)signum >= NSIG || signum == 0)
                panic("psignal signal number");
        mask = sigmask(signum);
        prop = sigprop[signum];

#if SIGNAL_DEBUG
        if(rdebug_proc && (p == rdebug_proc)) {
                ram_printf(3);
        }
#endif /* SIGNAL_DEBUG */

        if (thread_funnel_get() == (funnel_t *)network_flock) {
                sw_funnel = 1;
                thread_funnel_switch(NETWORK_FUNNEL, KERNEL_FUNNEL);
        }
        /*
         *      We will need the task pointer later.  Grab it now to
         *      check for a zombie process.  Also don't send signals
         *      to kernel internal tasks.
         */
        if (((sig_task = p->task) == TASK_NULL)  || is_kerneltask(sig_task)) {
                if (sw_funnel)
                        thread_funnel_switch(KERNEL_FUNNEL, NETWORK_FUNNEL);
                return;
        }

        /*
         * do not send signals to the process that has the thread
         * doing a reboot(). Not doing so will mark that thread aborted
         * and can cause IO failures wich will cause data loss.
         */
        if (ISSET(p->p_flag, P_REBOOT)) {
                if (sw_funnel)
                        thread_funnel_switch(KERNEL_FUNNEL, NETWORK_FUNNEL);
                return;
        }

        /* 
         * if the traced process is blocked waiting for
         * gdb then do not block the caller just pend 
         * the signal. Setup a callout  to process the
         * pended signal if not alreadu set
         */
        if (pend && (p->p_flag & P_TRACED) && p->sigwait) {
                p->p_sigpending |= mask;
                if (!(p->p_flag & P_SIGTHR)) {
                        p->p_flag |= P_SIGTHR;
                        thread_call_func((thread_call_func_t)psignal_pend, p,
                         FALSE);
                }
                if (sw_funnel)
                        thread_funnel_switch(KERNEL_FUNNEL, NETWORK_FUNNEL);
                return;
        }

        if (withlock)
                signal_lock(p);

        /*
         * If proc is traced, always give parent a chance.
         */
        if (p->p_flag & P_TRACED)
                action = SIG_DFL;
        else {
                /*
                 * If the signal is being ignored,
                 * then we forget about it immediately.
                 * (Note: we don't set SIGCONT in p_sigignore,
                 * and if it is set to SIG_IGN,
                 * action will be SIG_DFL here.)
                 */
                if (p->p_sigignore & mask)
                        goto psigout;
                if (p->p_sigmask & mask)
                        action = SIG_HOLD;
                else if (p->p_sigcatch & mask)
                        action = SIG_CATCH;
                else
                        action = SIG_DFL;
        }

        if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
                (p->p_flag & P_TRACED) == 0)
                p->p_nice = NZERO;

        if (prop & SA_CONT)
                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;
                p->p_siglist &= ~contsigmask;
        }
        p->p_siglist |= mask;

        /*
         * Defer further processing for signals which are held,
         * except that stopped processes must be continued by SIGCONT.
         */
        if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP))
                goto psigout;
                
        /*
         *      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.
         */
        
        cur_thread = current_thread();   /* this is a shuttle */
        cur_act = current_act();
        
        if ((p->p_flag & P_INVFORK) && p->p_vforkact) {
                        sig_thread_act = p->p_vforkact; 

                        kret = check_actforsig(sig_task, sig_thread_act, &sig_thread, 1);
                        if (kret == KERN_SUCCESS) {
                                goto psig_foundthread;
                        }
        } 

        /* If successful return with ast set */
        kret = (kern_return_t)get_signalact(sig_task, 
                                &sig_thread_act, &sig_thread, 1);

        if ((kret != KERN_SUCCESS) || (sig_thread_act == THREAD_NULL)) {
                /* XXXX FIXME
                /* if it is sigkill, may be we should
                * inject a thread to terminate
                */
#if DIAGNOSTIC
                printf("WARNING: no activation in psignal\n"); 
#endif
#if SIGNAL_DEBUG
        ram_printf(1);
#endif /* SIGNAL_DEBUG */
                        goto psigout;
                }

psig_foundthread:
        if (sig_thread == THREAD_NULL) {
#if DIAGNOSTIC
                printf("WARNING: valid act; but no shutte in psignal\n");
#endif
#if 0
                /* FIXME : NO VALID SHUTTLE */
                goto psigout;
#endif
        }

        /*
         *      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;
#if XXX
                /*
                 * we need to make changes here to get nice to work 
                 * reset priority to BASEPRI_USER
                 */
#endif
        }

        /*
         *      Process is traced - wake it up (if not already
         *      stopped) so that it can discover the signal in
         *      issig() and stop for the parent.
         */
        if (p->p_flag & P_TRACED) {
                if (p->p_stat != SSTOP)
                        goto run;
                else
                        goto psigout;
        }

        if (action != SIG_DFL) {
                /*
                 *      User wants to catch the signal.
                 *      Wake up the thread, but don't un-suspend it
                 *      (except for SIGCONT).
                 */
                if (prop & SA_CONT)
                        (void) task_resume(sig_task);
                goto 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, 1);
                                p->p_siglist &= ~mask;
                                goto psigout;
                        }
                        
                        /*
                         *      Stop the task.
                         */
                        if (!is_thread_running(sig_thread)) {
                                /*  Thread is not running 
                                 *      If task hasn't already been stopped by
                                 *      a signal, stop it.
                                 */
                                p->p_siglist &= ~mask;
                                if (get_task_userstop(sig_task) == 0) {
                                        /*
                                         * p_cursig must not be set, because
                                         * it will be psig()'d if it is not
                                         * zero, and the signal is being
                                         * handled here.  But save the signal
                                         * in p_stopsig so WUNTRACED
                                         * option to wait can find it.
                                         */
                                        p->p_xstat = signum;
                                        if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0)
                                                psignal(p->p_pptr, SIGCHLD);
                                        stop(p);
                                }
#if 0
                                /* unconditional check is bad */
                                signal_clearast(sig_thread_act);
#endif
                                goto psigout;
                        } else {
                                if (p->p_stat != SZOMB) 
                                        signal_setast(cur_act);
                                goto psigout;
                        }
                }

                switch (signum) {
                        /*
                         * Signals ignored by default have been dealt
                         * with already, since their bits are on in
                         * p_sigignore.
                         */

                case SIGKILL:
                        /*
                         * Kill signal always sets process running and
                         * unsuspends it.
                         */
                        /*
                         *      Process will be running after 'run'
                         */
                        p->p_stat = SRUN;

                        thread_abort(sig_thread_act);

                        goto psigout;

                case SIGCONT:
                        /*
                         * Let the process run.  If it's sleeping on an
                         * event, it remains so.
                         */
                        if (p->p_flag & P_TTYSLEEP) {
                                p->p_flag &= ~P_TTYSLEEP;
                                wakeup(&p->p_siglist);
                        } else {
                                (void) task_resume(sig_task);
                        }
                        p->p_siglist &= ~mask;
                        p->p_stat = SRUN;
#if 0
                        /* do not clear AST as tcsh is sendig SIGTERM followed by 
                         * SIGCONT and the ast was getting cleared unconditinally
                         * This is not right.
                         */
                        signal_clearast(sig_thread_act);
#endif
                        goto psigout;

                default:
                        /*
                         * All other signals wake up the process, but don't
                         * resume it.
                         */
                        goto run;
                }
        }
        /*NOTREACHED*/
run:
        /*
         * If we're being traced (possibly because someone attached us
         * while we were stopped), check for a signal from the debugger.
         */
        if (p->p_stat == SSTOP) {
                if ((p->p_flag & P_TRACED) != 0 && p->p_xstat != 0)
                        p->p_siglist |= sigmask(p->p_xstat); 
        }

        /*
         * setrunnable(p) in BSD
         */
        p->p_stat = SRUN;

        /*
         *      Wake up the thread if it is interruptible.
         */
        thread_abort_safely(sig_thread_act);
psigout:
        if (withlock) 
                signal_unlock(p);
        if (sw_funnel)
                thread_funnel_switch(KERNEL_FUNNEL, NETWORK_FUNNEL);
}

__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(current_act());
                        }
                        return(0);
                }
                if(assert_wait_possible()) {
                        assert_wait((caddr_t)&p->sigwait_thread, 
                                        (THREAD_INTERRUPTIBLE));
                }
                signal_unlock(p);
                thread_block(0);
                signal_lock(p);
                if (thread_should_abort(self)) {
                        /*
                         * Terminate request - clean up.
                         */
                        return -1;
                }
        }
        return 1;
}

/*
 * If the current process has received a signal (should be caught or cause
 * termination, should interrupt current syscall), return the signal number.
 * Stop signals with default action are processed immediately, then cleared;
 * they aren't returned.  This is checked after each entry to the system for
 * a syscall or trap (though this can usually be done without calling issignal
 * by checking the pending signal masks in the CURSIG macro.) The normal call
 * sequence is
 *
 *      while (signum = CURSIG(curproc))
 *              postsig(signum);
 */
int
issignal(p)
        register struct proc *p;
{
        register int signum, mask, prop, sigbits;
        task_t task = p->task;
        thread_t cur_thread;
        thread_act_t cur_act;
        int     s;
        struct uthread * ut;
        kern_return_t kret;

        cur_thread = current_thread();
        cur_act = current_act();

        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_sig |p->p_siglist) & ~p->p_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];

                if (mask & threadmask) {
                        /* we can take this signal */
                        ut->uu_sig &= ~mask;
                } 

                /*
                 * 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) {
                        p->p_siglist &= ~mask;          /* take the signal! */
                        continue;
                }
                if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) {
                        register int    hold;
                        register task_t task;
                        /*
                         * If traced, always stop, and stay
                         * stopped until released by the debugger.
                         */
                        /* ptrace debugging */
                        p->p_xstat = signum;
                        psignal(p->p_pptr, 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->p_siglist &= ~mask;  /* clear the old signal */

                        wakeup((caddr_t)p->p_pptr);
                        assert_wait((caddr_t)&p->sigwait, (THREAD_INTERRUPTIBLE));
                        thread_block(0);
                        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 (p->p_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);
                        if (mask & threadmask)
                                ut->uu_sig |= mask;
                        else
                                p->p_siglist |= mask;
                        if (p->p_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 */
                                p->p_xstat = signum;
                                stop(p);
                                if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0)
                                        psignal(p->p_pptr, SIGCHLD);
                                thread_block(0);
                                /*
                                 *      We may have to quit
                                 */
                                if (thread_should_abort(current_thread())) {
                                        signal_unlock(p);
                                        return(0);
                                }
                                break;
                        } else if (prop & SA_IGNORE) {
                                /*
                                 * Except for SIGCONT, shouldn't get here.
                                 * Default action is to ignore; drop it.
                                 */
                                break;          /* == ignore */
                        } else {
                                p->p_siglist &= ~mask;          /* take the signal! */
                                p->p_sigpending &= ~mask;       /* take the pending 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.
                         */
                        p->p_siglist &= ~mask;          /* take the signal! */
                        p->p_sigpending &= ~mask;       /* take the pending signal */
                        signal_unlock(p);
                        return (signum);
                }
                p->p_siglist &= ~mask;          /* take the signal! */
                p->p_sigpending &= ~mask;       /* take the pending signal */
                }
        /* NOTREACHED */
}

/* called from _sleep */
int
CURSIG(p)
    register struct proc *p;
{
        register int signum, mask, prop, sigbits;
        task_t task = p->task;
        thread_t cur_thread;
        thread_act_t cur_act;
        int     s;
        struct uthread * ut;
        int retnum = 0;
           
        if (p->p_siglist == 0)
                return (0);

        if (((p->p_siglist & ~p->p_sigmask) == 0) && ((p->p_flag & P_TRACED) == 0))
                return (0);

        cur_thread = current_thread();
        cur_act = current_act();

        ut = get_bsdthread_info(cur_act);

        sigbits = (ut->uu_sig | p->p_siglist) & ~p->p_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 (p->p_sigmask & mask)
                                continue;
                        return(signum);
                }

                /*
                 * Decide whether the signal should be returned.
                 * Return the signal's number, or fall through
                 * to clear it from the pending mask.
                 */

                switch ((long)p->p_sigacts->ps_sigact[signum]) {
                
                case (long)SIG_DFL:
                        /*
                         * Don't take default actions on system processes.
                         */
                        if (p->p_pptr->p_pid == 0) {
#if DIAGNOSTIC
                                /*
                                 * Are you sure you want to ignore SIGSEGV
                                 * in init? XXX
                                 */
                                printf("Process (pid %d) got signal %d\n",
                                        p->p_pid, signum);
#endif
                                break;                          /* == ignore */
                        }
                        
                        /*
                         * If there is a pending stop signal to process
                         * with default action, stop here,
                         * then clear the signal.  However,
                         * if process is member of an orphaned
                         * process group, ignore tty stop signals.
                         */
                        if (prop & SA_STOP) {
                                if (p->p_flag & P_TRACED ||
                                        (p->p_pgrp->pg_jobc == 0 &&
                                        prop & SA_TTYSTOP))
                                        break;  /* == ignore */
                                retnum = signum;
                                break;
                        } else if (prop & SA_IGNORE) {
                                /*
                                 * Except for SIGCONT, shouldn't get here.
                                 * Default action is to ignore; drop it.
                                 */
                                break;          /* == ignore */
                        } else {
                                return (signum);
                        }
                        /*NOTREACHED*/

                case (long)SIG_IGN:
                        /*
                         * Masking above should prevent us ever trying
                         * to take action on an ignored signal other
                         * than SIGCONT, unless process is traced.
                         */
                        if ((prop & SA_CONT) == 0 &&
                                (p->p_flag & P_TRACED) == 0)
                                printf("issignal\n");
                        break;          /* == ignore */

                default:
                        /*
                         * This signal has an action, let
                         * postsig() process it.
                         */
                        return (signum);
                }
                sigbits &= ~mask;               /* take the signal! */
        }
        /* NOTREACHED */
}

/*
 * Put the argument process into the stopped state and notify the parent
 * via wakeup.  Signals are handled elsewhere.  The process must not be
 * on the run queue.
 */
void
stop(p)
        register struct proc *p;
{
        p->p_stat = SSTOP;
        p->p_flag &= ~P_WAITED;
        wakeup((caddr_t)p->p_pptr);
        (void) task_suspend(p->task);   /*XXX*/
}

/*
 * Take the action for the specified signal
 * from the current set of pending signals.
 */
void
postsig(signum)
        register int signum;
{
        register struct proc *p = current_proc();
        register struct sigacts *ps = p->p_sigacts;
        register sig_t action;
        u_long code;
        int mask, returnmask;

#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;
        }

        mask = sigmask(signum);
        p->p_siglist &= ~mask;
        action = ps->ps_sigact[signum];
#if KTRACE
        if (KTRPOINT(p, KTR_PSIG))
                ktrpsig(p->p_tracep,
                    signum, action, ps->ps_flags & SAS_OLDMASK ?
                    ps->ps_oldmask : p->p_sigmask, 0);
#endif
        if (action == SIG_DFL) {
                /*
                 * Default action, where the default is to kill
                 * the process.  (Other cases were ignored above.)
                 */
                /* called with signal_lock() held */
                sigexit_locked(p, signum);
                return;
                /* NOTREACHED */
        } else {
                /*
                 * If we get here, the signal must be caught.
                 */
#if DIAGNOSTIC
                if (action == SIG_IGN || (p->p_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 (ps->ps_flags & SAS_OLDMASK) {
                        returnmask = ps->ps_oldmask;
                        ps->ps_flags &= ~SAS_OLDMASK;
                } else
                        returnmask = p->p_sigmask;
                p->p_sigmask |= ps->ps_catchmask[signum] | mask;
                if (ps->ps_sig != signum) {
                        code = 0;
                } else {
                        code = ps->ps_code;
                        ps->ps_code = 0;
                }
                p->p_stats->p_ru.ru_nsignals++;
                sendsig(p, action, signum, returnmask, code);
        }
        signal_unlock(p);
}

/*
 * Force the current process to exit with the specified signal, dumping core
 * if appropriate.  We bypass the normal tests for masked and caught signals,
 * allowing unrecoverable failures to terminate the process without changing
 * signal state.  Mark the accounting record with the signal termination.
 * If dumping core, save the signal number for the debugger.  Calls exit and
 * does not return.
 */
 /* called with signal lock */
void
sigexit_locked(p, signum)
        register struct proc *p;
        int signum;
{

        sig_lock_to_exit(p);
        p->p_acflag |= AXSIG;
        if (sigprop[signum] & SA_CORE) {
                p->p_sigacts->ps_sig = signum;
                if (coredump(p) == 0)
                        signum |= WCOREFLAG;
        }
        signal_unlock(p);
        exit1(p, W_EXITCODE(0, signum), (int *)NULL);
        /* NOTREACHED */
}

void
bsd_ast(thread_act_t thr_act)
{
        struct proc *p = current_proc();
        struct uthread *ut = get_bsdthread_info(thr_act);
        int     signum;
        unsigned int pc;
        boolean_t funnel_state;

        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);
        }
        ast_off(AST_BSD);

        (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, 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, 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, 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);
                }
        }
}