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

     /*
      * 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
     * $FreeBSD$
     */
    
    #include "opt_compat.h"
    #include "opt_ktrace.h"
    
    #define SIGPROP         /* include signal properties table */
    #include <sys/param.h>
    #include <sys/kernel.h>
    #include <sys/sysproto.h>
    #include <sys/signalvar.h>
    #include <sys/resourcevar.h>
    #include <sys/namei.h>
    #include <sys/vnode.h>
    #include <sys/proc.h>
    #include <sys/pioctl.h>
    #include <sys/systm.h>
    #include <sys/acct.h>
    #include <sys/fcntl.h>
    #include <sys/wait.h>
    #include <sys/ktrace.h>
    #include <sys/syslog.h>
    #include <sys/stat.h>
    #include <sys/sysent.h>
    #include <sys/sysctl.h>
    #include <sys/malloc.h>
    
    #include <machine/cpu.h>
    #ifdef SMP
    #include <machine/smp.h>
    #endif
    
    static int killpg1      __P((struct proc *cp, int signum, int pgid, int all));
    static void setsigvec   __P((struct proc *p, int signum, struct sigaction *sa));
    static void stop        __P((struct proc *));
    static char *expand_name        __P((const char *, uid_t, pid_t));
    static int coredump     __P((struct proc *));
    
    static int      kern_logsigexit = 1;
    SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, &kern_logsigexit, 0, "");
    
    /*
     * Can process p, with pcred pc, send the signal signum to process q?
     */
    #define CANSIGNAL(p, pc, q, signum) \
            ((pc)->pc_ucred->cr_uid == 0 || \
                (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 || \
                ((signum) == SIGCONT && (q)->p_session == (p)->p_session))
    
    /*
     * Policy -- Can real uid ruid with ucred uc send a signal to process q?
     */
    #define CANSIGIO(ruid, uc, q) \
            ((uc)->cr_uid == 0 || \
                (ruid) == (q)->p_cred->p_ruid || \
                (uc)->cr_uid == (q)->p_cred->p_ruid || \
                (ruid) == (q)->p_ucred->cr_uid || \
                (uc)->cr_uid == (q)->p_ucred->cr_uid)
   
   int sugid_coredump;
   SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, &sugid_coredump, 0, "");
   
   #ifndef _SYS_SYSPROTO_H_
   struct sigaction_args {
           int     signum;
           struct  sigaction *nsa;
           struct  sigaction *osa;
   };
   #endif
   /* ARGSUSED */
   int
   sigaction(p, uap)
           struct proc *p;
           register struct sigaction_args *uap;
   {
           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)
                   return (EINVAL);
           sa = &vec;
           if (uap->osa) {
                   sa->sa_handler = ps->ps_sigact[signum];
                   sa->sa_mask = ps->ps_catchmask[signum];
                   bit = sigmask(signum);
                   sa->sa_flags = 0;
                   if ((ps->ps_sigonstack & bit) != 0)
                           sa->sa_flags |= SA_ONSTACK;
                   if ((ps->ps_sigintr & bit) == 0)
                           sa->sa_flags |= SA_RESTART;
                   if ((ps->ps_sigreset & bit) != 0)
                           sa->sa_flags |= SA_RESETHAND;
                   if ((ps->ps_signodefer & bit) != 0)
                           sa->sa_flags |= SA_NODEFER;
                   if (signum == SIGCHLD && p->p_procsig->ps_flag & P_NOCLDSTOP)
                           sa->sa_flags |= SA_NOCLDSTOP;
                   if (signum == SIGCHLD && p->p_procsig->ps_flag & P_NOCLDWAIT)
                           sa->sa_flags |= SA_NOCLDWAIT;
                   if ((error = copyout((caddr_t)sa, (caddr_t)uap->osa,
                       sizeof (vec))))
                           return (error);
           }
           if (uap->nsa) {
                   if ((error = copyin((caddr_t)uap->nsa, (caddr_t)sa,
                       sizeof (vec))))
                           return (error);
                   if ((signum == SIGKILL || signum == SIGSTOP) &&
                       sa->sa_handler != SIG_DFL)
                           return (EINVAL);
                   setsigvec(p, signum, sa);
           }
           return (0);
   }
   
   static 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.
            */
           (void) splhigh();
           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_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;
   #ifdef COMPAT_SUNOS
           if (sa->sa_flags & SA_USERTRAMP)
                   ps->ps_usertramp |= bit;
           else
                   ps->ps_usertramp &= ~bit;
   #endif
           if (signum == SIGCHLD) {
                   if (sa->sa_flags & SA_NOCLDSTOP)
                           p->p_procsig->ps_flag |= P_NOCLDSTOP;
                   else
                           p->p_procsig->ps_flag &= ~P_NOCLDSTOP;
                   if (sa->sa_flags & SA_NOCLDWAIT) {
                           /*
                            * Paranoia: since SA_NOCLDWAIT is implemented by
                            * reparenting the dying child to PID 1 (and
                            * trust it to reap the zombie), PID 1 itself is
                            * forbidden to set SA_NOCLDWAIT.
                            */
                           if (p->p_pid == 1)
                                   p->p_procsig->ps_flag &= ~P_NOCLDWAIT;
                           else
                                   p->p_procsig->ps_flag |= P_NOCLDWAIT;
                   } else
                           p->p_procsig->ps_flag &= ~P_NOCLDWAIT;
           }
           /*
            * 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 (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;
           }
           (void) spl0();
   }
   
   /*
    * 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 = SS_DISABLE;
           ps->ps_sigstk.ss_size = 0;
           ps->ps_sigstk.ss_sp = 0;
           ps->ps_flags = 0;
           /*
            * Reset no zombies if child dies flag as Solaris does.
            */
           p->p_procsig->ps_flag &= ~P_NOCLDWAIT;
   }
   
   /*
    * Manipulate signal mask.
    * Note that we receive new mask, not pointer,
    * and return old mask as return value;
    * the library stub does the rest.
    */
   #ifndef _SYS_SYSPROTO_H_
   struct sigprocmask_args {
           int     how;
           sigset_t mask;
   };
   #endif
   int
   sigprocmask(p, uap)
           register struct proc *p;
           struct sigprocmask_args *uap;
   {
           int error = 0;
   
           p->p_retval[0] = p->p_sigmask;
           (void) splhigh();
   
           switch (uap->how) {
           case SIG_BLOCK:
                   p->p_sigmask |= uap->mask &~ sigcantmask;
                   break;
   
           case SIG_UNBLOCK:
                   p->p_sigmask &= ~uap->mask;
                   break;
   
           case SIG_SETMASK:
                   p->p_sigmask = uap->mask &~ sigcantmask;
                   break;
   
           default:
                   error = EINVAL;
                   break;
           }
           (void) spl0();
           return (error);
   }
   
   #ifndef _SYS_SYSPROTO_H_
   struct sigpending_args {
           int     dummy;
   };
   #endif
   /* ARGSUSED */
   int
   sigpending(p, uap)
           struct proc *p;
           struct sigpending_args *uap;
   {
   
           p->p_retval[0] = p->p_siglist;
           return (0);
   }
   
   #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
   /*
    * Generalized interface signal handler, 4.3-compatible.
    */
   #ifndef _SYS_SYSPROTO_H_
   struct osigvec_args {
           int     signum;
           struct  sigvec *nsv;
           struct  sigvec *osv;
   };
   #endif
   /* ARGSUSED */
   int
   osigvec(p, uap)
           struct proc *p;
           register struct osigvec_args *uap;
   {
           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)
                   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 ((ps->ps_sigreset & bit) != 0)
                           sv->sv_flags |= SV_RESETHAND;
                   if ((ps->ps_signodefer & bit) != 0)
                           sv->sv_flags |= SV_NODEFER;
   #ifndef COMPAT_SUNOS
                   if (signum == SIGCHLD && p->p_procsig->ps_flag & P_NOCLDSTOP)
                           sv->sv_flags |= SV_NOCLDSTOP;
   #endif
                   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);
                   if ((signum == SIGKILL || signum == SIGSTOP) &&
                       sv->sv_handler != SIG_DFL)
                           return (EINVAL);
   #ifdef COMPAT_SUNOS
                   sv->sv_flags |= SA_USERTRAMP;
   #endif
                   sv->sv_flags ^= SA_RESTART;     /* opposite of SV_INTERRUPT */
                   setsigvec(p, signum, (struct sigaction *)sv);
           }
           return (0);
   }
   
   #ifndef _SYS_SYSPROTO_H_
   struct osigblock_args {
           int     mask;
   };
   #endif
   int
   osigblock(p, uap)
           register struct proc *p;
           struct osigblock_args *uap;
   {
   
           (void) splhigh();
           p->p_retval[0] = p->p_sigmask;
           p->p_sigmask |= uap->mask &~ sigcantmask;
           (void) spl0();
           return (0);
   }
   
   #ifndef _SYS_SYSPROTO_H_
   struct osigsetmask_args {
           int     mask;
   };
   #endif
   int
   osigsetmask(p, uap)
           struct proc *p;
           struct osigsetmask_args *uap;
   {
   
           (void) splhigh();
           p->p_retval[0] = p->p_sigmask;
           p->p_sigmask = uap->mask &~ sigcantmask;
           (void) spl0();
           return (0);
   }
   #endif /* COMPAT_43 || COMPAT_SUNOS */
   
   /*
    * 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.
    */
   #ifndef _SYS_SYSPROTO_H_
   struct sigsuspend_args {
           sigset_t mask;
   };
   #endif
   /* ARGSUSED */
   int
   sigsuspend(p, uap)
           register struct proc *p;
           struct sigsuspend_args *uap;
   {
           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.
            */
           p->p_oldsigmask = p->p_sigmask;
           p->p_sigmask = uap->mask &~ sigcantmask;
           while (tsleep((caddr_t) ps, PPAUSE|PCATCH, "pause", 0) == 0)
                   /* void */;
           /* always return EINTR rather than ERESTART... */
           return (EINTR);
   }
   
   #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
   #ifndef _SYS_SYSPROTO_H_
   struct osigstack_args {
           struct  sigstack *nss;
           struct  sigstack *oss;
   };
   #endif
   /* ARGSUSED */
   int
   osigstack(p, uap)
           struct proc *p;
           register struct osigstack_args *uap;
   {
           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 & SS_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 & SS_ONSTACK;
                   psp->ps_flags |= SAS_ALTSTACK;
           }
           return (error);
   }
   #endif /* COMPAT_43 || COMPAT_SUNOS */
   
   #ifndef _SYS_SYSPROTO_H_
   struct sigaltstack_args {
           struct  sigaltstack *nss;
           struct  sigaltstack *oss;
   };
   #endif
   /* ARGSUSED */
   int
   sigaltstack(p, uap)
           struct proc *p;
           register struct sigaltstack_args *uap;
   {
           struct sigacts *psp;
           struct sigaltstack ss;
           int error;
   
           psp = p->p_sigacts;
           if ((psp->ps_flags & SAS_ALTSTACK) == 0)
                   psp->ps_sigstk.ss_flags |= SS_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 & SS_DISABLE) {
                   if (psp->ps_sigstk.ss_flags & SS_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);
   }
   
   /*
    * 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);
   }
   
   #ifndef _SYS_SYSPROTO_H_
   struct kill_args {
           int     pid;
           int     signum;
   };
   #endif
   /* ARGSUSED */
   int
   kill(cp, uap)
           register struct proc *cp;
           register struct kill_args *uap;
   {
           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 defined(COMPAT_43) || defined(COMPAT_SUNOS)
   #ifndef _SYS_SYSPROTO_H_
   struct okillpg_args {
           int     pgid;
           int     signum;
   };
   #endif
   /* ARGSUSED */
   int
   okillpg(p, uap)
           struct proc *p;
           register struct okillpg_args *uap;
   {
   
           if ((u_int)uap->signum >= NSIG)
                   return (EINVAL);
           return (killpg1(p, uap->signum, uap->pgid, 0));
   }
   #endif /* COMPAT_43 || COMPAT_SUNOS */
   
   /*
    * 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 the current process.
    * If it will be caught immediately, deliver it with correct code.
    * Otherwise, post it normally.
    */
   void
   trapsignal(p, signum, code)
           struct proc *p;
           register int signum;
           u_long code;
   {
           register struct sigacts *ps = p->p_sigacts;
           int mask;
   
           mask = sigmask(signum);
           if ((p->p_flag & P_TRACED) == 0 && (p->p_sigcatch & mask) != 0 &&
               (p->p_sigmask & mask) == 0) {
                   p->p_stats->p_ru.ru_nsignals++;
   #ifdef KTRACE
                   if (KTRPOINT(p, KTR_PSIG))
                           ktrpsig(p->p_tracep, signum, ps->ps_sigact[signum],
                                   p->p_sigmask, code);
   #endif
                   (*p->p_sysent->sv_sendsig)(ps->ps_sigact[signum], signum,
                                                   p->p_sigmask, code);
                   p->p_sigmask |= ps->ps_catchmask[signum] |
                                   (mask & ~ps->ps_signodefer);
                   if ((ps->ps_sigreset & mask) != 0) {
                           /*
                            * See setsigvec() for origin of this code.
                            */
                           p->p_sigcatch &= ~mask;
                           if (signum != SIGCONT && sigprop[signum] & SA_IGNORE)
                                   p->p_sigignore |= mask;
                           ps->ps_sigact[signum] = SIG_DFL;
                   }
           } else {
                   p->p_code = code;       /* XXX for core dump/debugger */
                   p->p_sig = signum;      /* XXX to verify code */
                   psignal(p, signum);
           }
   }
   
   /*
    * 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(p, signum)
           register struct proc *p;
           register int signum;
   {
           register int s, prop;
           register sig_t action;
           int mask;
   
           if ((u_int)signum >= NSIG || signum == 0) {
                   printf("psignal: signum %d\n", signum);
                   panic("psignal signal number");
           }
           mask = sigmask(signum);
           prop = sigprop[signum];
   
           /*
            * If proc is traced, always give parent a chance;
            * if signal event is tracked by procfs, give *that*
            * a chance, as well.
            */
           if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG))
                   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) || (p->p_flag & P_WEXIT))
                           return;
                   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)
                           return;
                   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))
                   return;
           s = splhigh();
           switch (p->p_stat) {
   
           case SSLEEP:
                   /*
                    * If process is sleeping uninterruptibly
                    * we can't interrupt the sleep... the signal will
                    * be noticed when the process returns through
                    * trap() or syscall().
                    */
                   if ((p->p_flag & P_SINTR) == 0)
                           goto out;
                   /*
                    * Process is sleeping and traced... make it runnable
                    * so it can discover the signal in issignal() and stop
                    * for the parent.
                    */
                   if (p->p_flag & P_TRACED)
                           goto run;
                   /*
                    * If SIGCONT is default (or ignored) and process is
                    * asleep, we are finished; the process should not
                    * be awakened.
                    */
                   if ((prop & SA_CONT) && action == SIG_DFL) {
                           p->p_siglist &= ~mask;
                           goto out;
                   }
                   /*
                    * When a sleeping process receives a stop
                    * signal, process immediately if possible.
                    * All other (caught or default) signals
                    * cause the process to run.
                    */
                   if (prop & SA_STOP) {
                           if (action != SIG_DFL)
                                   goto runfast;
                           /*
                            * If a child holding parent blocked,
                            * stopping could cause deadlock.
                            */
                           if (p->p_flag & P_PPWAIT)
                                   goto out;
                           p->p_siglist &= ~mask;
                           p->p_xstat = signum;
                           if ((p->p_pptr->p_procsig->ps_flag & P_NOCLDSTOP) == 0)
                                   psignal(p->p_pptr, SIGCHLD);
                           stop(p);
                           goto out;
                   } else
                           goto runfast;
                   /*NOTREACHED*/
   
           case SSTOP:
                   /*
                    * If traced process is already stopped,
                    * then no further action is necessary.
                    */
                   if (p->p_flag & P_TRACED)
                           goto out;
   
                   /*
                    * Kill signal always sets processes running.
                    */
                   if (signum == SIGKILL)
                           goto runfast;
   
                   if (prop & SA_CONT) {
                           /*
                            * If SIGCONT is default (or ignored), we continue the
                            * process but don't leave the signal in p_siglist, as
                            * it has no further action.  If SIGCONT is held, we
                            * continue the process and leave the signal in
                            * p_siglist.  If the process catches SIGCONT, let it
                            * handle the signal itself.  If it isn't waiting on
                            * an event, then it goes back to run state.
                            * Otherwise, process goes back to sleep state.
                            */
                           if (action == SIG_DFL)
                                   p->p_siglist &= ~mask;
                           if (action == SIG_CATCH)
                                   goto runfast;
                           if (p->p_wchan == 0)
                                   goto run;
                           p->p_stat = SSLEEP;
                           goto out;
                   }
   
                   if (prop & SA_STOP) {
                           /*
                            * Already stopped, don't need to stop again.
                            * (If we did the shell could get confused.)
                            */
                           p->p_siglist &= ~mask;          /* take it away */
                           goto out;
                   }
   
                   /*
                    * If process is sleeping interruptibly, then simulate a
                    * wakeup so that when it is continued, it will be made
                    * runnable and can look at the signal.  But don't make
                    * the process runnable, leave it stopped.
                    */
                   if (p->p_wchan && p->p_flag & P_SINTR)
                           unsleep(p);
                   goto out;
   
           default:
                   /*
                    * SRUN, SIDL, SZOMB do nothing with the signal,
                    * other than kicking ourselves if we are running.
                    * It will either never be noticed, or noticed very soon.
                    */
                   if (p == curproc)
                           signotify(p);
   #ifdef SMP
                   else if (p->p_stat == SRUN)
                           forward_signal(p);
   #endif
                   goto out;
           }
           /*NOTREACHED*/
   
   runfast:
           /*
            * Raise priority to at least PUSER.
            */
           if (p->p_priority > PUSER)
                   p->p_priority = PUSER;
   run:
           setrunnable(p);
   out:
           splx(s);
   }
   
   /*
    * 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;
   
           for (;;) {
                   int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
   
                   mask = p->p_siglist & ~p->p_sigmask;
                   if (p->p_flag & P_PPWAIT)
                           mask &= ~stopsigmask;
                   if (mask == 0)          /* no signal to send */
                           return (0);
                   signum = ffs((long)mask);
                   mask = sigmask(signum);
                   prop = sigprop[signum];
   
                   STOPEVENT(p, S_SIG, signum);
   
                   /*
                    * We should see pending but ignored signals
                    * only if P_TRACED was on when they were posted.
                    */
                   if ((mask & p->p_sigignore) && (traced == 0)) {
                           p->p_siglist &= ~mask;
                           continue;
                   }
                  if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) {
                          /*
                           * If traced, always stop, and stay
                           * stopped until released by the parent.
                           */
                          p->p_xstat = signum;
                          psignal(p->p_pptr, SIGCHLD);
                          do {
                                  stop(p);
                                  mi_switch();
                          } while (!trace_req(p)
                                   && p->p_flag & P_TRACED);
  
                          /*
                           * If the traced bit got turned off, go back up
                           * to the top to rescan signals.  This ensures
                           * that p_sig* and ps_sigact are consistent.
                           */
                          if ((p->p_flag & P_TRACED) == 0)
                                  continue;
  
                          /*
                           * If parent wants us to take the signal,
                           * then it will leave it in p->p_xstat;
                           * otherwise we just look for signals again.
                           */
                          p->p_siglist &= ~mask;  /* clear the old signal */
                          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);
                          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 ((int)(intptr_t)p->p_sigacts->ps_sigact[signum]) {
  
                  case (int)SIG_DFL:
                          /*
                           * Don't take default actions on system processes.
                           */
                          if (p->p_pid <= 1) {
  #ifdef DIAGNOSTIC
                                  /*
                                   * Are you sure you want to ignore SIGSEGV
                                   * in init? XXX
                                   */
                                  printf("Process (pid %lu) got signal %d\n",
                                          (u_long)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_procsig->ps_flag & P_NOCLDSTOP) == 0)
                                          psignal(p->p_pptr, SIGCHLD);
                                  mi_switch();
                                  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 (int)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);
                  }
                  p->p_siglist &= ~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);
  }
  
  /*
   * Take the action for the specified signal
   * from the current set of pending signals.
   */
  void
  postsig(signum)
          register int signum;
  {
          register struct proc *p = curproc;
          register struct sigacts *ps = p->p_sigacts;
          register sig_t action;
          int code, mask, returnmask;
  
          KASSERT(signum != 0, ("postsig"));
  
          mask = sigmask(signum);
          p->p_siglist &= ~mask;
          action = ps->ps_sigact[signum];
  #ifdef KTRACE
          if (KTRPOINT(p, KTR_PSIG))
                  ktrpsig(p->p_tracep,
                      signum, action, p->p_oldsigmask ?
                      p->p_oldsigmask : p->p_sigmask, 0);
  #endif
          STOPEVENT(p, S_SIG, signum);
  
          if (action == SIG_DFL) {
                  /*
                   * Default action, where the default is to kill
                   * the process.  (Other cases were ignored above.)
                   */
                  sigexit(p, signum);
                  /* NOTREACHED */
          } else {
                  /*
                   * If we get here, the signal must be caught.
                   */
                  KASSERT(action != SIG_IGN && (p->p_sigmask & mask) == 0,
                      ("postsig action"));
                  /*
                   * 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.
                   */
                  (void) splhigh();
                  if (p->p_oldsigmask) {
                          returnmask = p->p_oldsigmask;
                          p->p_oldsigmask = 0;
                  } else
                          returnmask = p->p_sigmask;
                  p->p_sigmask |= ps->ps_catchmask[signum] |
                                  (mask & ~ps->ps_signodefer);
                  if ((ps->ps_sigreset & mask) != 0) {
                          /*
                           * See setsigvec() for origin of this code.
                           */
                          p->p_sigcatch &= ~mask;
                          if (signum != SIGCONT && sigprop[signum] & SA_IGNORE)
                                  p->p_sigignore |= mask;
                          ps->ps_sigact[signum] = SIG_DFL;
                  }
                  (void) spl0();
                  p->p_stats->p_ru.ru_nsignals++;
                  if (p->p_sig != signum) {
                          code = 0;
                  } else {
                          code = p->p_code;
                          p->p_code = 0;
                          p->p_sig = 0;
                  }
                  (*p->p_sysent->sv_sendsig)(action, signum, returnmask, code);
          }
  }
  
  /*
   * Kill the current process for stated reason.
   */
  void
  killproc(p, why)
          struct proc *p;
          char *why;
  {
          log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm,
                  p->p_cred && p->p_ucred ? p->p_ucred->cr_uid : -1, why);
          psignal(p, SIGKILL);
  }
  
  /*
   * 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.
   */
  void
  sigexit(p, signum)
          register struct proc *p;
          int signum;
  {
  
          p->p_acflag |= AXSIG;
          if (sigprop[signum] & SA_CORE) {
                  p->p_sig = signum;
                  /*
                   * Log signals which would cause core dumps
                   * (Log as LOG_INFO to appease those who don't want
                   * these messages.)
                   * XXX : Todo, as well as euid, write out ruid too
                   */
                  if (coredump(p) == 0)
                          signum |= WCOREFLAG;
                  if (kern_logsigexit)
                          log(LOG_INFO,
                              "pid %d (%s), uid %d: exited on signal %d%s\n",
                              p->p_pid, p->p_comm,
                              p->p_cred && p->p_ucred ? p->p_ucred->cr_uid : -1,
                              signum &~ WCOREFLAG,
                              signum & WCOREFLAG ? " (core dumped)" : "");
          }
          exit1(p, W_EXITCODE(0, signum));
          /* NOTREACHED */
  }
  
  static char corefilename[MAXPATHLEN+1] = {"%N.core"};
  SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
                sizeof(corefilename), "process corefile name format string");
  
  /*
   * expand_name(name, uid, pid)
   * Expand the name described in corefilename, using name, uid, and pid.
   * corefilename is a printf-like string, with three format specifiers:
   *      %N      name of process ("name")
   *      %P      process id (pid)
   *      %U      user id (uid)
   * For example, "%N.core" is the default; they can be disabled completely
   * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
   * This is controlled by the sysctl variable kern.corefile (see above).
   */
  
  static char *
  expand_name(name, uid, pid)
  const char *name; uid_t uid; pid_t pid; {
          char *temp;
          char buf[11];           /* Buffer for pid/uid -- max 4B */
          int i, n;
          char *format = corefilename;
  
          temp = malloc(MAXPATHLEN + 3, M_TEMP, M_NOWAIT);
          if (temp == NULL)
                  return NULL;
          bzero(temp, MAXPATHLEN+3);
          for (i = 0, n = 0; i < MAXPATHLEN && format[i]; i++) {
                  int l;
                  switch (format[i]) {
                  case '%':       /* Format character */
                          i++;
                          switch (format[i]) {
                          case '%':
                                  temp[n++] = '%';
                                  break;
                          case 'N':       /* process name */
                                  l = strlen(name);
                                  if ((n + l) > MAXPATHLEN) {
                                          log(LOG_ERR, "pid %d (%s), uid (%d):  Path `%s%s' is too long\n",
                                              pid, name, uid, temp, name);
                                          free(temp, M_TEMP);
                                          return NULL;
                                  }
                                  memcpy(temp+n, name, l);
                                  n += l;
                                  break;
                          case 'P':       /* process id */
                                  sprintf(buf, "%u", pid);
                                  l = strlen(buf);
                                  if ((n + l) > MAXPATHLEN) {
                                          log(LOG_ERR, "pid %d (%s), uid (%d):  Path `%s%s' is too long\n",
                                              pid, name, uid, temp, name);
                                          free(temp, M_TEMP);
                                          return NULL;
                                  }
                                  memcpy(temp+n, buf, l);
                                  n += l;
                                  break;
                          case 'U':       /* user id */
                                  sprintf(buf, "%u", uid);
                                  l = strlen(buf);
                                  if ((n + l) > MAXPATHLEN) {
                                          log(LOG_ERR, "pid %d (%s), uid (%d):  Path `%s%s' is too long\n",
                                              pid, name, uid, temp, name);
                                          free(temp, M_TEMP);
                                          return NULL;
                                  }
                                  memcpy(temp+n, buf, l);
                                  n += l;
                                  break;
                          default:
                                  log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
                          }
                          break;
                  default:
                          temp[n++] = format[i];
                  }
          }
          return temp;
  }
  
  /*
   * Dump a process' core.  The main routine does some
   * policy checking, and creates the name of the coredump;
   * then it passes on a vnode and a size limit to the process-specific
   * coredump routine if there is one; if there _is not_ one, it returns
   * ENOSYS; otherwise it returns the error from the process-specific routine.
   */
  
  static int
  coredump(p)
          register struct proc *p;
  {
          register struct vnode *vp;
          register struct ucred *cred = p->p_cred->pc_ucred;
          struct nameidata nd;
          struct vattr vattr;
          int error, error1;
          char *name;                     /* name of corefile */
          off_t limit;
          
          STOPEVENT(p, S_CORE, 0);
  
          if ((sugid_coredump == 0) && p->p_flag & P_SUGID)
                  return (EFAULT);
          
          /*
           * Note that the bulk of limit checking is done after
           * the corefile is created.  The exception is if the limit
           * for corefiles is 0, in which case we don't bother
           * creating the corefile at all.  This layout means that
           * a corefile is truncated instead of not being created,
           * if it is larger than the limit.
           */
          limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
          if (limit == 0)
                  return 0;
  
          name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
          NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p);
          error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
          free(name, M_TEMP);
          if (error)
                  return (error);
          vp = nd.ni_vp;
  
          /* Don't dump to non-regular files or files with links. */
          if (vp->v_type != VREG ||
              VOP_GETATTR(vp, &vattr, cred, p) || vattr.va_nlink != 1) {
                  error = EFAULT;
                  goto out;
          }
          VATTR_NULL(&vattr);
          vattr.va_size = 0;
          VOP_LEASE(vp, p, cred, LEASE_WRITE);
          VOP_SETATTR(vp, &vattr, cred, p);
          p->p_acflag |= ACORE;
  
          error = p->p_sysent->sv_coredump ?
            p->p_sysent->sv_coredump(p, vp, limit) :
            ENOSYS;
  
  out:
          VOP_UNLOCK(vp, 0, p);
          error1 = vn_close(vp, FWRITE, cred, p);
          if (error == 0)
                  error = error1;
          return (error);
  }
  
  /*
   * Nonexistent system call-- signal process (may want to handle it).
   * Flag error in case process won't see signal immediately (blocked or ignored).
   */
  #ifndef _SYS_SYSPROTO_H_
  struct nosys_args {
          int     dummy;
  };
  #endif
  /* ARGSUSED */
  int
  nosys(p, args)
          struct proc *p;
          struct nosys_args *args;
  {
  
          psignal(p, SIGSYS);
          return (EINVAL);
  }
  
  /*
   * Send a signal to a SIGIO or SIGURG to a process or process group using
   * stored credentials rather than those of the current process.
   */
  void
  pgsigio(sigio, signum, checkctty)
          struct sigio *sigio;
          int signum, checkctty;
  {
          if (sigio == NULL)
                  return;
                  
          if (sigio->sio_pgid > 0) {
                  if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
                               sigio->sio_proc))
                          psignal(sigio->sio_proc, signum);
          } else if (sigio->sio_pgid < 0) {
                  struct proc *p;
  
                  for (p = sigio->sio_pgrp->pg_members.lh_first; p != NULL;
                       p = p->p_pglist.le_next)
                          if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
                              (checkctty == 0 || (p->p_flag & P_CONTROLT)))
                                  psignal(p, signum);
          }
  }

Cache object: 3f611ab3f75e18a4004e3e8282d69c67