The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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

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    1 /*-
    2  * Copyright (c) 1982, 1986, 1989, 1991, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  * (c) UNIX System Laboratories, Inc.
    5  * All or some portions of this file are derived from material licensed
    6  * to the University of California by American Telephone and Telegraph
    7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
    8  * the permission of UNIX System Laboratories, Inc.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)kern_sig.c  8.7 (Berkeley) 4/18/94
   35  */
   36 
   37 #include <sys/cdefs.h>
   38 __FBSDID("$FreeBSD: stable/6/sys/kern/kern_sig.c 208319 2010-05-19 22:36:46Z attilio $");
   39 
   40 #include "opt_compat.h"
   41 #include "opt_ktrace.h"
   42 
   43 #include <sys/param.h>
   44 #include <sys/systm.h>
   45 #include <sys/signalvar.h>
   46 #include <sys/vnode.h>
   47 #include <sys/acct.h>
   48 #include <sys/condvar.h>
   49 #include <sys/event.h>
   50 #include <sys/fcntl.h>
   51 #include <sys/kernel.h>
   52 #include <sys/kse.h>
   53 #include <sys/ktr.h>
   54 #include <sys/ktrace.h>
   55 #include <sys/lock.h>
   56 #include <sys/malloc.h>
   57 #include <sys/mutex.h>
   58 #include <sys/namei.h>
   59 #include <sys/proc.h>
   60 #include <sys/pioctl.h>
   61 #include <sys/resourcevar.h>
   62 #include <sys/sched.h>
   63 #include <sys/sleepqueue.h>
   64 #include <sys/smp.h>
   65 #include <sys/stat.h>
   66 #include <sys/sx.h>
   67 #include <sys/syscallsubr.h>
   68 #include <sys/sysctl.h>
   69 #include <sys/sysent.h>
   70 #include <sys/syslog.h>
   71 #include <sys/sysproto.h>
   72 #include <sys/unistd.h>
   73 #include <sys/wait.h>
   74 
   75 #include <machine/cpu.h>
   76 
   77 #include <security/audit/audit.h>
   78 
   79 #if defined (__alpha__) && !defined(COMPAT_43)
   80 #error "You *really* need COMPAT_43 on the alpha for longjmp(3)"
   81 #endif
   82 
   83 #define ONSIG   32              /* NSIG for osig* syscalls.  XXX. */
   84 
   85 static int      coredump(struct thread *);
   86 static char     *expand_name(const char *, uid_t, pid_t);
   87 static int      killpg1(struct thread *td, int sig, int pgid, int all);
   88 static int      issignal(struct thread *p);
   89 static int      sigprop(int sig);
   90 static void     tdsigwakeup(struct thread *, int, sig_t, int);
   91 static void     sig_suspend_threads(struct thread *, struct proc *, int);
   92 static int      filt_sigattach(struct knote *kn);
   93 static void     filt_sigdetach(struct knote *kn);
   94 static int      filt_signal(struct knote *kn, long hint);
   95 static struct thread *sigtd(struct proc *p, int sig, int prop);
   96 static int      kern_sigtimedwait(struct thread *td, sigset_t set,
   97                                 siginfo_t *info, struct timespec *timeout);
   98 static void     do_tdsignal(struct thread *td, int sig, sigtarget_t target);
   99 
  100 struct filterops sig_filtops =
  101         { 0, filt_sigattach, filt_sigdetach, filt_signal };
  102 
  103 static int      kern_logsigexit = 1;
  104 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, 
  105     &kern_logsigexit, 0, 
  106     "Log processes quitting on abnormal signals to syslog(3)");
  107 
  108 /*
  109  * Policy -- Can ucred cr1 send SIGIO to process cr2?
  110  * Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG
  111  * in the right situations.
  112  */
  113 #define CANSIGIO(cr1, cr2) \
  114         ((cr1)->cr_uid == 0 || \
  115             (cr1)->cr_ruid == (cr2)->cr_ruid || \
  116             (cr1)->cr_uid == (cr2)->cr_ruid || \
  117             (cr1)->cr_ruid == (cr2)->cr_uid || \
  118             (cr1)->cr_uid == (cr2)->cr_uid)
  119 
  120 int sugid_coredump;
  121 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, 
  122     &sugid_coredump, 0, "Enable coredumping set user/group ID processes");
  123 
  124 static int      do_coredump = 1;
  125 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
  126         &do_coredump, 0, "Enable/Disable coredumps");
  127 
  128 static int      set_core_nodump_flag = 0;
  129 SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag,
  130         0, "Enable setting the NODUMP flag on coredump files");
  131 
  132 /*
  133  * Signal properties and actions.
  134  * The array below categorizes the signals and their default actions
  135  * according to the following properties:
  136  */
  137 #define SA_KILL         0x01            /* terminates process by default */
  138 #define SA_CORE         0x02            /* ditto and coredumps */
  139 #define SA_STOP         0x04            /* suspend process */
  140 #define SA_TTYSTOP      0x08            /* ditto, from tty */
  141 #define SA_IGNORE       0x10            /* ignore by default */
  142 #define SA_CONT         0x20            /* continue if suspended */
  143 #define SA_CANTMASK     0x40            /* non-maskable, catchable */
  144 #define SA_PROC         0x80            /* deliverable to any thread */
  145 
  146 static int sigproptbl[NSIG] = {
  147         SA_KILL|SA_PROC,                /* SIGHUP */
  148         SA_KILL|SA_PROC,                /* SIGINT */
  149         SA_KILL|SA_CORE|SA_PROC,        /* SIGQUIT */
  150         SA_KILL|SA_CORE,                /* SIGILL */
  151         SA_KILL|SA_CORE,                /* SIGTRAP */
  152         SA_KILL|SA_CORE,                /* SIGABRT */
  153         SA_KILL|SA_CORE|SA_PROC,        /* SIGEMT */
  154         SA_KILL|SA_CORE,                /* SIGFPE */
  155         SA_KILL|SA_PROC,                /* SIGKILL */
  156         SA_KILL|SA_CORE,                /* SIGBUS */
  157         SA_KILL|SA_CORE,                /* SIGSEGV */
  158         SA_KILL|SA_CORE,                /* SIGSYS */
  159         SA_KILL|SA_PROC,                /* SIGPIPE */
  160         SA_KILL|SA_PROC,                /* SIGALRM */
  161         SA_KILL|SA_PROC,                /* SIGTERM */
  162         SA_IGNORE|SA_PROC,              /* SIGURG */
  163         SA_STOP|SA_PROC,                /* SIGSTOP */
  164         SA_STOP|SA_TTYSTOP|SA_PROC,     /* SIGTSTP */
  165         SA_IGNORE|SA_CONT|SA_PROC,      /* SIGCONT */
  166         SA_IGNORE|SA_PROC,              /* SIGCHLD */
  167         SA_STOP|SA_TTYSTOP|SA_PROC,     /* SIGTTIN */
  168         SA_STOP|SA_TTYSTOP|SA_PROC,     /* SIGTTOU */
  169         SA_IGNORE|SA_PROC,              /* SIGIO */
  170         SA_KILL,                        /* SIGXCPU */
  171         SA_KILL,                        /* SIGXFSZ */
  172         SA_KILL|SA_PROC,                /* SIGVTALRM */
  173         SA_KILL|SA_PROC,                /* SIGPROF */
  174         SA_IGNORE|SA_PROC,              /* SIGWINCH  */
  175         SA_IGNORE|SA_PROC,              /* SIGINFO */
  176         SA_KILL|SA_PROC,                /* SIGUSR1 */
  177         SA_KILL|SA_PROC,                /* SIGUSR2 */
  178 };
  179 
  180 /*
  181  * Determine signal that should be delivered to process p, the current
  182  * process, 0 if none.  If there is a pending stop signal with default
  183  * action, the process stops in issignal().
  184  * XXXKSE   the check for a pending stop is not done under KSE
  185  *
  186  * MP SAFE.
  187  */
  188 int
  189 cursig(struct thread *td)
  190 {
  191         PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
  192         mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED);
  193         mtx_assert(&sched_lock, MA_NOTOWNED);
  194         return (SIGPENDING(td) ? issignal(td) : 0);
  195 }
  196 
  197 /*
  198  * Arrange for ast() to handle unmasked pending signals on return to user
  199  * mode.  This must be called whenever a signal is added to td_siglist or
  200  * unmasked in td_sigmask.
  201  */
  202 void
  203 signotify(struct thread *td)
  204 {
  205         struct proc *p;
  206         sigset_t set, saved;
  207 
  208         p = td->td_proc;
  209 
  210         PROC_LOCK_ASSERT(p, MA_OWNED);
  211 
  212         /*
  213          * If our mask changed we may have to move signal that were
  214          * previously masked by all threads to our siglist.
  215          */
  216         set = p->p_siglist;
  217         if (p->p_flag & P_SA)
  218                 saved = p->p_siglist;
  219         SIGSETNAND(set, td->td_sigmask);
  220         SIGSETNAND(p->p_siglist, set);
  221         SIGSETOR(td->td_siglist, set);
  222 
  223         if (SIGPENDING(td)) {
  224                 mtx_lock_spin(&sched_lock);
  225                 td->td_flags |= TDF_NEEDSIGCHK | TDF_ASTPENDING;
  226                 mtx_unlock_spin(&sched_lock);
  227         }
  228         if ((p->p_flag & P_SA) && !(p->p_flag & P_SIGEVENT)) {
  229                 if (!SIGSETEQ(saved, p->p_siglist)) {
  230                         /* pending set changed */
  231                         p->p_flag |= P_SIGEVENT;
  232                         wakeup(&p->p_siglist);
  233                 }
  234         }
  235 }
  236 
  237 int
  238 sigonstack(size_t sp)
  239 {
  240         struct thread *td = curthread;
  241 
  242         return ((td->td_pflags & TDP_ALTSTACK) ?
  243 #if defined(COMPAT_43)
  244             ((td->td_sigstk.ss_size == 0) ?
  245                 (td->td_sigstk.ss_flags & SS_ONSTACK) :
  246                 ((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size))
  247 #else
  248             ((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size)
  249 #endif
  250             : 0);
  251 }
  252 
  253 static __inline int
  254 sigprop(int sig)
  255 {
  256 
  257         if (sig > 0 && sig < NSIG)
  258                 return (sigproptbl[_SIG_IDX(sig)]);
  259         return (0);
  260 }
  261 
  262 int
  263 sig_ffs(sigset_t *set)
  264 {
  265         int i;
  266 
  267         for (i = 0; i < _SIG_WORDS; i++)
  268                 if (set->__bits[i])
  269                         return (ffs(set->__bits[i]) + (i * 32));
  270         return (0);
  271 }
  272 
  273 /*
  274  * kern_sigaction
  275  * sigaction
  276  * freebsd4_sigaction
  277  * osigaction
  278  *
  279  * MPSAFE
  280  */
  281 int
  282 kern_sigaction(td, sig, act, oact, flags)
  283         struct thread *td;
  284         register int sig;
  285         struct sigaction *act, *oact;
  286         int flags;
  287 {
  288         struct sigacts *ps;
  289         struct thread *td0;
  290         struct proc *p = td->td_proc;
  291 
  292         if (!_SIG_VALID(sig))
  293                 return (EINVAL);
  294 
  295         PROC_LOCK(p);
  296         ps = p->p_sigacts;
  297         mtx_lock(&ps->ps_mtx);
  298         if (oact) {
  299                 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
  300                 oact->sa_flags = 0;
  301                 if (SIGISMEMBER(ps->ps_sigonstack, sig))
  302                         oact->sa_flags |= SA_ONSTACK;
  303                 if (!SIGISMEMBER(ps->ps_sigintr, sig))
  304                         oact->sa_flags |= SA_RESTART;
  305                 if (SIGISMEMBER(ps->ps_sigreset, sig))
  306                         oact->sa_flags |= SA_RESETHAND;
  307                 if (SIGISMEMBER(ps->ps_signodefer, sig))
  308                         oact->sa_flags |= SA_NODEFER;
  309                 if (SIGISMEMBER(ps->ps_siginfo, sig)) {
  310                         oact->sa_flags |= SA_SIGINFO;
  311                         oact->sa_sigaction =
  312                             (__siginfohandler_t *)ps->ps_sigact[_SIG_IDX(sig)];
  313                 } else
  314                         oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
  315                 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDSTOP)
  316                         oact->sa_flags |= SA_NOCLDSTOP;
  317                 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDWAIT)
  318                         oact->sa_flags |= SA_NOCLDWAIT;
  319         }
  320         if (act) {
  321                 if ((sig == SIGKILL || sig == SIGSTOP) &&
  322                     act->sa_handler != SIG_DFL) {
  323                         mtx_unlock(&ps->ps_mtx);
  324                         PROC_UNLOCK(p);
  325                         return (EINVAL);
  326                 }
  327 
  328                 /*
  329                  * Change setting atomically.
  330                  */
  331 
  332                 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
  333                 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
  334                 if (act->sa_flags & SA_SIGINFO) {
  335                         ps->ps_sigact[_SIG_IDX(sig)] =
  336                             (__sighandler_t *)act->sa_sigaction;
  337                         SIGADDSET(ps->ps_siginfo, sig);
  338                 } else {
  339                         ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
  340                         SIGDELSET(ps->ps_siginfo, sig);
  341                 }
  342                 if (!(act->sa_flags & SA_RESTART))
  343                         SIGADDSET(ps->ps_sigintr, sig);
  344                 else
  345                         SIGDELSET(ps->ps_sigintr, sig);
  346                 if (act->sa_flags & SA_ONSTACK)
  347                         SIGADDSET(ps->ps_sigonstack, sig);
  348                 else
  349                         SIGDELSET(ps->ps_sigonstack, sig);
  350                 if (act->sa_flags & SA_RESETHAND)
  351                         SIGADDSET(ps->ps_sigreset, sig);
  352                 else
  353                         SIGDELSET(ps->ps_sigreset, sig);
  354                 if (act->sa_flags & SA_NODEFER)
  355                         SIGADDSET(ps->ps_signodefer, sig);
  356                 else
  357                         SIGDELSET(ps->ps_signodefer, sig);
  358                 if (sig == SIGCHLD) {
  359                         if (act->sa_flags & SA_NOCLDSTOP)
  360                                 ps->ps_flag |= PS_NOCLDSTOP;
  361                         else
  362                                 ps->ps_flag &= ~PS_NOCLDSTOP;
  363                         if (act->sa_flags & SA_NOCLDWAIT) {
  364                                 /*
  365                                  * Paranoia: since SA_NOCLDWAIT is implemented
  366                                  * by reparenting the dying child to PID 1 (and
  367                                  * trust it to reap the zombie), PID 1 itself
  368                                  * is forbidden to set SA_NOCLDWAIT.
  369                                  */
  370                                 if (p->p_pid == 1)
  371                                         ps->ps_flag &= ~PS_NOCLDWAIT;
  372                                 else
  373                                         ps->ps_flag |= PS_NOCLDWAIT;
  374                         } else
  375                                 ps->ps_flag &= ~PS_NOCLDWAIT;
  376                         if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
  377                                 ps->ps_flag |= PS_CLDSIGIGN;
  378                         else
  379                                 ps->ps_flag &= ~PS_CLDSIGIGN;
  380                 }
  381                 /*
  382                  * Set bit in ps_sigignore for signals that are set to SIG_IGN,
  383                  * and for signals set to SIG_DFL where the default is to
  384                  * ignore. However, don't put SIGCONT in ps_sigignore, as we
  385                  * have to restart the process.
  386                  */
  387                 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
  388                     (sigprop(sig) & SA_IGNORE &&
  389                      ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
  390                         if ((p->p_flag & P_SA) &&
  391                              SIGISMEMBER(p->p_siglist, sig)) {
  392                                 p->p_flag |= P_SIGEVENT;
  393                                 wakeup(&p->p_siglist);
  394                         }
  395                         /* never to be seen again */
  396                         SIGDELSET(p->p_siglist, sig);
  397                         mtx_lock_spin(&sched_lock);
  398                         FOREACH_THREAD_IN_PROC(p, td0)
  399                                 SIGDELSET(td0->td_siglist, sig);
  400                         mtx_unlock_spin(&sched_lock);
  401                         if (sig != SIGCONT)
  402                                 /* easier in psignal */
  403                                 SIGADDSET(ps->ps_sigignore, sig);
  404                         SIGDELSET(ps->ps_sigcatch, sig);
  405                 } else {
  406                         SIGDELSET(ps->ps_sigignore, sig);
  407                         if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
  408                                 SIGDELSET(ps->ps_sigcatch, sig);
  409                         else
  410                                 SIGADDSET(ps->ps_sigcatch, sig);
  411                 }
  412 #ifdef COMPAT_FREEBSD4
  413                 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
  414                     ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
  415                     (flags & KSA_FREEBSD4) == 0)
  416                         SIGDELSET(ps->ps_freebsd4, sig);
  417                 else
  418                         SIGADDSET(ps->ps_freebsd4, sig);
  419 #endif
  420 #ifdef COMPAT_43
  421                 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
  422                     ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
  423                     (flags & KSA_OSIGSET) == 0)
  424                         SIGDELSET(ps->ps_osigset, sig);
  425                 else
  426                         SIGADDSET(ps->ps_osigset, sig);
  427 #endif
  428         }
  429         mtx_unlock(&ps->ps_mtx);
  430         PROC_UNLOCK(p);
  431         return (0);
  432 }
  433 
  434 #ifndef _SYS_SYSPROTO_H_
  435 struct sigaction_args {
  436         int     sig;
  437         struct  sigaction *act;
  438         struct  sigaction *oact;
  439 };
  440 #endif
  441 /*
  442  * MPSAFE
  443  */
  444 int
  445 sigaction(td, uap)
  446         struct thread *td;
  447         register struct sigaction_args *uap;
  448 {
  449         struct sigaction act, oact;
  450         register struct sigaction *actp, *oactp;
  451         int error;
  452 
  453         actp = (uap->act != NULL) ? &act : NULL;
  454         oactp = (uap->oact != NULL) ? &oact : NULL;
  455         if (actp) {
  456                 error = copyin(uap->act, actp, sizeof(act));
  457                 if (error)
  458                         return (error);
  459         }
  460         error = kern_sigaction(td, uap->sig, actp, oactp, 0);
  461         if (oactp && !error)
  462                 error = copyout(oactp, uap->oact, sizeof(oact));
  463         return (error);
  464 }
  465 
  466 #ifdef COMPAT_FREEBSD4
  467 #ifndef _SYS_SYSPROTO_H_
  468 struct freebsd4_sigaction_args {
  469         int     sig;
  470         struct  sigaction *act;
  471         struct  sigaction *oact;
  472 };
  473 #endif
  474 /*
  475  * MPSAFE
  476  */
  477 int
  478 freebsd4_sigaction(td, uap)
  479         struct thread *td;
  480         register struct freebsd4_sigaction_args *uap;
  481 {
  482         struct sigaction act, oact;
  483         register struct sigaction *actp, *oactp;
  484         int error;
  485 
  486 
  487         actp = (uap->act != NULL) ? &act : NULL;
  488         oactp = (uap->oact != NULL) ? &oact : NULL;
  489         if (actp) {
  490                 error = copyin(uap->act, actp, sizeof(act));
  491                 if (error)
  492                         return (error);
  493         }
  494         error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4);
  495         if (oactp && !error)
  496                 error = copyout(oactp, uap->oact, sizeof(oact));
  497         return (error);
  498 }
  499 #endif  /* COMAPT_FREEBSD4 */
  500 
  501 #ifdef COMPAT_43        /* XXX - COMPAT_FBSD3 */
  502 #ifndef _SYS_SYSPROTO_H_
  503 struct osigaction_args {
  504         int     signum;
  505         struct  osigaction *nsa;
  506         struct  osigaction *osa;
  507 };
  508 #endif
  509 /*
  510  * MPSAFE
  511  */
  512 int
  513 osigaction(td, uap)
  514         struct thread *td;
  515         register struct osigaction_args *uap;
  516 {
  517         struct osigaction sa;
  518         struct sigaction nsa, osa;
  519         register struct sigaction *nsap, *osap;
  520         int error;
  521 
  522         if (uap->signum <= 0 || uap->signum >= ONSIG)
  523                 return (EINVAL);
  524 
  525         nsap = (uap->nsa != NULL) ? &nsa : NULL;
  526         osap = (uap->osa != NULL) ? &osa : NULL;
  527 
  528         if (nsap) {
  529                 error = copyin(uap->nsa, &sa, sizeof(sa));
  530                 if (error)
  531                         return (error);
  532                 nsap->sa_handler = sa.sa_handler;
  533                 nsap->sa_flags = sa.sa_flags;
  534                 OSIG2SIG(sa.sa_mask, nsap->sa_mask);
  535         }
  536         error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
  537         if (osap && !error) {
  538                 sa.sa_handler = osap->sa_handler;
  539                 sa.sa_flags = osap->sa_flags;
  540                 SIG2OSIG(osap->sa_mask, sa.sa_mask);
  541                 error = copyout(&sa, uap->osa, sizeof(sa));
  542         }
  543         return (error);
  544 }
  545 
  546 #if !defined(__i386__) && !defined(__alpha__)
  547 /* Avoid replicating the same stub everywhere */
  548 int
  549 osigreturn(td, uap)
  550         struct thread *td;
  551         struct osigreturn_args *uap;
  552 {
  553 
  554         return (nosys(td, (struct nosys_args *)uap));
  555 }
  556 #endif
  557 #endif /* COMPAT_43 */
  558 
  559 /*
  560  * Initialize signal state for process 0;
  561  * set to ignore signals that are ignored by default.
  562  */
  563 void
  564 siginit(p)
  565         struct proc *p;
  566 {
  567         register int i;
  568         struct sigacts *ps;
  569 
  570         PROC_LOCK(p);
  571         ps = p->p_sigacts;
  572         mtx_lock(&ps->ps_mtx);
  573         for (i = 1; i <= NSIG; i++)
  574                 if (sigprop(i) & SA_IGNORE && i != SIGCONT)
  575                         SIGADDSET(ps->ps_sigignore, i);
  576         mtx_unlock(&ps->ps_mtx);
  577         PROC_UNLOCK(p);
  578 }
  579 
  580 /*
  581  * Reset signals for an exec of the specified process.
  582  */
  583 void
  584 execsigs(struct proc *p)
  585 {
  586         struct sigacts *ps;
  587         int sig;
  588         struct thread *td;
  589 
  590         /*
  591          * Reset caught signals.  Held signals remain held
  592          * through td_sigmask (unless they were caught,
  593          * and are now ignored by default).
  594          */
  595         PROC_LOCK_ASSERT(p, MA_OWNED);
  596         td = FIRST_THREAD_IN_PROC(p);
  597         ps = p->p_sigacts;
  598         mtx_lock(&ps->ps_mtx);
  599         while (SIGNOTEMPTY(ps->ps_sigcatch)) {
  600                 sig = sig_ffs(&ps->ps_sigcatch);
  601                 SIGDELSET(ps->ps_sigcatch, sig);
  602                 if (sigprop(sig) & SA_IGNORE) {
  603                         if (sig != SIGCONT)
  604                                 SIGADDSET(ps->ps_sigignore, sig);
  605                         SIGDELSET(p->p_siglist, sig);
  606                         /*
  607                          * There is only one thread at this point.
  608                          */
  609                         SIGDELSET(td->td_siglist, sig);
  610                 }
  611                 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
  612         }
  613         /*
  614          * Reset stack state to the user stack.
  615          * Clear set of signals caught on the signal stack.
  616          */
  617         td->td_sigstk.ss_flags = SS_DISABLE;
  618         td->td_sigstk.ss_size = 0;
  619         td->td_sigstk.ss_sp = 0;
  620         td->td_pflags &= ~TDP_ALTSTACK;
  621         /*
  622          * Reset no zombies if child dies flag as Solaris does.
  623          */
  624         ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
  625         if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
  626                 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
  627         mtx_unlock(&ps->ps_mtx);
  628 }
  629 
  630 /*
  631  * kern_sigprocmask()
  632  *
  633  *      Manipulate signal mask.
  634  */
  635 int
  636 kern_sigprocmask(td, how, set, oset, old)
  637         struct thread *td;
  638         int how;
  639         sigset_t *set, *oset;
  640         int old;
  641 {
  642         int error;
  643 
  644         PROC_LOCK(td->td_proc);
  645         if (oset != NULL)
  646                 *oset = td->td_sigmask;
  647 
  648         error = 0;
  649         if (set != NULL) {
  650                 switch (how) {
  651                 case SIG_BLOCK:
  652                         SIG_CANTMASK(*set);
  653                         SIGSETOR(td->td_sigmask, *set);
  654                         break;
  655                 case SIG_UNBLOCK:
  656                         SIGSETNAND(td->td_sigmask, *set);
  657                         signotify(td);
  658                         break;
  659                 case SIG_SETMASK:
  660                         SIG_CANTMASK(*set);
  661                         if (old)
  662                                 SIGSETLO(td->td_sigmask, *set);
  663                         else
  664                                 td->td_sigmask = *set;
  665                         signotify(td);
  666                         break;
  667                 default:
  668                         error = EINVAL;
  669                         break;
  670                 }
  671         }
  672         PROC_UNLOCK(td->td_proc);
  673         return (error);
  674 }
  675 
  676 /*
  677  * sigprocmask() - MP SAFE
  678  */
  679 
  680 #ifndef _SYS_SYSPROTO_H_
  681 struct sigprocmask_args {
  682         int     how;
  683         const sigset_t *set;
  684         sigset_t *oset;
  685 };
  686 #endif
  687 int
  688 sigprocmask(td, uap)
  689         register struct thread *td;
  690         struct sigprocmask_args *uap;
  691 {
  692         sigset_t set, oset;
  693         sigset_t *setp, *osetp;
  694         int error;
  695 
  696         setp = (uap->set != NULL) ? &set : NULL;
  697         osetp = (uap->oset != NULL) ? &oset : NULL;
  698         if (setp) {
  699                 error = copyin(uap->set, setp, sizeof(set));
  700                 if (error)
  701                         return (error);
  702         }
  703         error = kern_sigprocmask(td, uap->how, setp, osetp, 0);
  704         if (osetp && !error) {
  705                 error = copyout(osetp, uap->oset, sizeof(oset));
  706         }
  707         return (error);
  708 }
  709 
  710 #ifdef COMPAT_43        /* XXX - COMPAT_FBSD3 */
  711 /*
  712  * osigprocmask() - MP SAFE
  713  */
  714 #ifndef _SYS_SYSPROTO_H_
  715 struct osigprocmask_args {
  716         int     how;
  717         osigset_t mask;
  718 };
  719 #endif
  720 int
  721 osigprocmask(td, uap)
  722         register struct thread *td;
  723         struct osigprocmask_args *uap;
  724 {
  725         sigset_t set, oset;
  726         int error;
  727 
  728         OSIG2SIG(uap->mask, set);
  729         error = kern_sigprocmask(td, uap->how, &set, &oset, 1);
  730         SIG2OSIG(oset, td->td_retval[0]);
  731         return (error);
  732 }
  733 #endif /* COMPAT_43 */
  734 
  735 #ifndef _SYS_SYSPROTO_H_
  736 struct sigpending_args {
  737         sigset_t        *set;
  738 };
  739 #endif
  740 /*
  741  * MPSAFE
  742  */
  743 int
  744 sigwait(struct thread *td, struct sigwait_args *uap)
  745 {
  746         siginfo_t info;
  747         sigset_t set;
  748         int error;
  749 
  750         error = copyin(uap->set, &set, sizeof(set));
  751         if (error) {
  752                 td->td_retval[0] = error;
  753                 return (0);
  754         }
  755 
  756         error = kern_sigtimedwait(td, set, &info, NULL);
  757         if (error) {
  758                 if (error == ERESTART)
  759                         return (error);
  760                 td->td_retval[0] = error;
  761                 return (0);
  762         }
  763 
  764         error = copyout(&info.si_signo, uap->sig, sizeof(info.si_signo));
  765         /* Repost if we got an error. */
  766         if (error && info.si_signo) {
  767                 PROC_LOCK(td->td_proc);
  768                 tdsignal(td, info.si_signo, SIGTARGET_TD);
  769                 PROC_UNLOCK(td->td_proc);
  770         }
  771         td->td_retval[0] = error;
  772         return (0);
  773 }
  774 /*
  775  * MPSAFE
  776  */
  777 int
  778 sigtimedwait(struct thread *td, struct sigtimedwait_args *uap)
  779 {
  780         struct timespec ts;
  781         struct timespec *timeout;
  782         sigset_t set;
  783         siginfo_t info;
  784         int error;
  785 
  786         if (uap->timeout) {
  787                 error = copyin(uap->timeout, &ts, sizeof(ts));
  788                 if (error)
  789                         return (error);
  790 
  791                 timeout = &ts;
  792         } else
  793                 timeout = NULL;
  794 
  795         error = copyin(uap->set, &set, sizeof(set));
  796         if (error)
  797                 return (error);
  798 
  799         error = kern_sigtimedwait(td, set, &info, timeout);
  800         if (error)
  801                 return (error);
  802 
  803         if (uap->info)
  804                 error = copyout(&info, uap->info, sizeof(info));
  805         /* Repost if we got an error. */
  806         if (error && info.si_signo) {
  807                 PROC_LOCK(td->td_proc);
  808                 tdsignal(td, info.si_signo, SIGTARGET_TD);
  809                 PROC_UNLOCK(td->td_proc);
  810         } else {
  811                 td->td_retval[0] = info.si_signo; 
  812         }
  813         return (error);
  814 }
  815 
  816 /*
  817  * MPSAFE
  818  */
  819 int
  820 sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap)
  821 {
  822         siginfo_t info;
  823         sigset_t set;
  824         int error;
  825 
  826         error = copyin(uap->set, &set, sizeof(set));
  827         if (error)
  828                 return (error);
  829 
  830         error = kern_sigtimedwait(td, set, &info, NULL);
  831         if (error)
  832                 return (error);
  833 
  834         if (uap->info)
  835                 error = copyout(&info, uap->info, sizeof(info));
  836         /* Repost if we got an error. */
  837         if (error && info.si_signo) {
  838                 PROC_LOCK(td->td_proc);
  839                 tdsignal(td, info.si_signo, SIGTARGET_TD);
  840                 PROC_UNLOCK(td->td_proc);
  841         } else {
  842                 td->td_retval[0] = info.si_signo;
  843         }
  844         return (error);
  845 }
  846 
  847 static int
  848 kern_sigtimedwait(struct thread *td, sigset_t waitset, siginfo_t *info,
  849     struct timespec *timeout)
  850 {
  851         struct sigacts *ps;
  852         sigset_t savedmask;
  853         struct proc *p;
  854         int error, sig, hz, i, timevalid = 0;
  855         struct timespec rts, ets, ts;
  856         struct timeval tv;
  857 
  858         p = td->td_proc;
  859         error = 0;
  860         sig = 0;
  861         SIG_CANTMASK(waitset);
  862 
  863         PROC_LOCK(p);
  864         ps = p->p_sigacts;
  865         savedmask = td->td_sigmask;
  866         if (timeout) {
  867                 if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) {
  868                         timevalid = 1;
  869                         getnanouptime(&rts);
  870                         ets = rts;
  871                         timespecadd(&ets, timeout);
  872                 }
  873         }
  874 
  875 restart:
  876         for (i = 1; i <= _SIG_MAXSIG; ++i) {
  877                 if (!SIGISMEMBER(waitset, i))
  878                         continue;
  879                 if (!SIGISMEMBER(td->td_siglist, i)) {
  880                         if (SIGISMEMBER(p->p_siglist, i)) {
  881                                 if (p->p_flag & P_SA) {
  882                                         p->p_flag |= P_SIGEVENT;
  883                                         wakeup(&p->p_siglist);
  884                                 }
  885                                 SIGDELSET(p->p_siglist, i);
  886                                 SIGADDSET(td->td_siglist, i);
  887                         } else
  888                                 continue;
  889                 }
  890 
  891                 SIGFILLSET(td->td_sigmask);
  892                 SIG_CANTMASK(td->td_sigmask);
  893                 SIGDELSET(td->td_sigmask, i);
  894                 mtx_lock(&ps->ps_mtx);
  895                 sig = cursig(td);
  896                 mtx_unlock(&ps->ps_mtx);
  897                 if (sig)
  898                         goto out;
  899                 else {
  900                         /*
  901                          * Because cursig() may have stopped current thread,
  902                          * after it is resumed, things may have already been 
  903                          * changed, it should rescan any pending signals.
  904                          */
  905                         goto restart;
  906                 }
  907         }
  908         if (error)
  909                 goto out;
  910 
  911         /*
  912          * POSIX says this must be checked after looking for pending
  913          * signals.
  914          */
  915         if (timeout) {
  916                 if (!timevalid) {
  917                         error = EINVAL;
  918                         goto out;
  919                 }
  920                 getnanouptime(&rts);
  921                 if (timespeccmp(&rts, &ets, >=)) {
  922                         error = EAGAIN;
  923                         goto out;
  924                 }
  925                 ts = ets;
  926                 timespecsub(&ts, &rts);
  927                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
  928                 hz = tvtohz(&tv);
  929         } else
  930                 hz = 0;
  931 
  932         td->td_sigmask = savedmask;
  933         SIGSETNAND(td->td_sigmask, waitset);
  934         signotify(td);
  935         error = msleep(&ps, &p->p_mtx, PPAUSE|PCATCH, "sigwait", hz);
  936         if (timeout) {
  937                 if (error == ERESTART) {
  938                         /* timeout can not be restarted. */
  939                         error = EINTR;
  940                 } else if (error == EAGAIN) {
  941                         /* will calculate timeout by ourself. */
  942                         error = 0;
  943                 }
  944         }
  945         goto restart;
  946 
  947 out:
  948         td->td_sigmask = savedmask;
  949         signotify(td);
  950         if (sig) {
  951                 SIGDELSET(td->td_siglist, sig);
  952                 bzero(info, sizeof(*info));
  953                 info->si_signo = sig;
  954                 info->si_code = 0;
  955                 error = 0;
  956 
  957 #ifdef KTRACE
  958                 if (KTRPOINT(td, KTR_PSIG))  {
  959                         sig_t action;
  960 
  961                         mtx_lock(&ps->ps_mtx);
  962                         action = ps->ps_sigact[_SIG_IDX(sig)];
  963                         mtx_unlock(&ps->ps_mtx);
  964                         ktrpsig(sig, action, &td->td_sigmask, 0);
  965                 }
  966 #endif
  967                 _STOPEVENT(p, S_SIG, sig);
  968 
  969                 if (sig == SIGKILL) {
  970                         p->p_code = 0;
  971                         p->p_sig = sig;
  972                         sigexit(td, sig);
  973                 }
  974         }
  975         PROC_UNLOCK(p);
  976         return (error);
  977 }
  978 
  979 /*
  980  * MPSAFE
  981  */
  982 int
  983 sigpending(td, uap)
  984         struct thread *td;
  985         struct sigpending_args *uap;
  986 {
  987         struct proc *p = td->td_proc;
  988         sigset_t siglist;
  989 
  990         PROC_LOCK(p);
  991         siglist = p->p_siglist;
  992         SIGSETOR(siglist, td->td_siglist);
  993         PROC_UNLOCK(p);
  994         return (copyout(&siglist, uap->set, sizeof(sigset_t)));
  995 }
  996 
  997 #ifdef COMPAT_43        /* XXX - COMPAT_FBSD3 */
  998 #ifndef _SYS_SYSPROTO_H_
  999 struct osigpending_args {
 1000         int     dummy;
 1001 };
 1002 #endif
 1003 /*
 1004  * MPSAFE
 1005  */
 1006 int
 1007 osigpending(td, uap)
 1008         struct thread *td;
 1009         struct osigpending_args *uap;
 1010 {
 1011         struct proc *p = td->td_proc;
 1012         sigset_t siglist;
 1013 
 1014         PROC_LOCK(p);
 1015         siglist = p->p_siglist;
 1016         SIGSETOR(siglist, td->td_siglist);
 1017         PROC_UNLOCK(p);
 1018         SIG2OSIG(siglist, td->td_retval[0]);
 1019         return (0);
 1020 }
 1021 #endif /* COMPAT_43 */
 1022 
 1023 #if defined(COMPAT_43)
 1024 /*
 1025  * Generalized interface signal handler, 4.3-compatible.
 1026  */
 1027 #ifndef _SYS_SYSPROTO_H_
 1028 struct osigvec_args {
 1029         int     signum;
 1030         struct  sigvec *nsv;
 1031         struct  sigvec *osv;
 1032 };
 1033 #endif
 1034 /*
 1035  * MPSAFE
 1036  */
 1037 /* ARGSUSED */
 1038 int
 1039 osigvec(td, uap)
 1040         struct thread *td;
 1041         register struct osigvec_args *uap;
 1042 {
 1043         struct sigvec vec;
 1044         struct sigaction nsa, osa;
 1045         register struct sigaction *nsap, *osap;
 1046         int error;
 1047 
 1048         if (uap->signum <= 0 || uap->signum >= ONSIG)
 1049                 return (EINVAL);
 1050         nsap = (uap->nsv != NULL) ? &nsa : NULL;
 1051         osap = (uap->osv != NULL) ? &osa : NULL;
 1052         if (nsap) {
 1053                 error = copyin(uap->nsv, &vec, sizeof(vec));
 1054                 if (error)
 1055                         return (error);
 1056                 nsap->sa_handler = vec.sv_handler;
 1057                 OSIG2SIG(vec.sv_mask, nsap->sa_mask);
 1058                 nsap->sa_flags = vec.sv_flags;
 1059                 nsap->sa_flags ^= SA_RESTART;   /* opposite of SV_INTERRUPT */
 1060         }
 1061         error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
 1062         if (osap && !error) {
 1063                 vec.sv_handler = osap->sa_handler;
 1064                 SIG2OSIG(osap->sa_mask, vec.sv_mask);
 1065                 vec.sv_flags = osap->sa_flags;
 1066                 vec.sv_flags &= ~SA_NOCLDWAIT;
 1067                 vec.sv_flags ^= SA_RESTART;
 1068                 error = copyout(&vec, uap->osv, sizeof(vec));
 1069         }
 1070         return (error);
 1071 }
 1072 
 1073 #ifndef _SYS_SYSPROTO_H_
 1074 struct osigblock_args {
 1075         int     mask;
 1076 };
 1077 #endif
 1078 /*
 1079  * MPSAFE
 1080  */
 1081 int
 1082 osigblock(td, uap)
 1083         register struct thread *td;
 1084         struct osigblock_args *uap;
 1085 {
 1086         struct proc *p = td->td_proc;
 1087         sigset_t set;
 1088 
 1089         OSIG2SIG(uap->mask, set);
 1090         SIG_CANTMASK(set);
 1091         PROC_LOCK(p);
 1092         SIG2OSIG(td->td_sigmask, td->td_retval[0]);
 1093         SIGSETOR(td->td_sigmask, set);
 1094         PROC_UNLOCK(p);
 1095         return (0);
 1096 }
 1097 
 1098 #ifndef _SYS_SYSPROTO_H_
 1099 struct osigsetmask_args {
 1100         int     mask;
 1101 };
 1102 #endif
 1103 /*
 1104  * MPSAFE
 1105  */
 1106 int
 1107 osigsetmask(td, uap)
 1108         struct thread *td;
 1109         struct osigsetmask_args *uap;
 1110 {
 1111         struct proc *p = td->td_proc;
 1112         sigset_t set;
 1113 
 1114         OSIG2SIG(uap->mask, set);
 1115         SIG_CANTMASK(set);
 1116         PROC_LOCK(p);
 1117         SIG2OSIG(td->td_sigmask, td->td_retval[0]);
 1118         SIGSETLO(td->td_sigmask, set);
 1119         signotify(td);
 1120         PROC_UNLOCK(p);
 1121         return (0);
 1122 }
 1123 #endif /* COMPAT_43 */
 1124 
 1125 /*
 1126  * Suspend process until signal, providing mask to be set
 1127  * in the meantime. 
 1128  ***** XXXKSE this doesn't make sense under KSE.
 1129  ***** Do we suspend the thread or all threads in the process?
 1130  ***** How do we suspend threads running NOW on another processor?
 1131  */
 1132 #ifndef _SYS_SYSPROTO_H_
 1133 struct sigsuspend_args {
 1134         const sigset_t *sigmask;
 1135 };
 1136 #endif
 1137 /*
 1138  * MPSAFE
 1139  */
 1140 /* ARGSUSED */
 1141 int
 1142 sigsuspend(td, uap)
 1143         struct thread *td;
 1144         struct sigsuspend_args *uap;
 1145 {
 1146         sigset_t mask;
 1147         int error;
 1148 
 1149         error = copyin(uap->sigmask, &mask, sizeof(mask));
 1150         if (error)
 1151                 return (error);
 1152         return (kern_sigsuspend(td, mask));
 1153 }
 1154 
 1155 int
 1156 kern_sigsuspend(struct thread *td, sigset_t mask)
 1157 {
 1158         struct proc *p = td->td_proc;
 1159 
 1160         /*
 1161          * When returning from sigsuspend, we want
 1162          * the old mask to be restored after the
 1163          * signal handler has finished.  Thus, we
 1164          * save it here and mark the sigacts structure
 1165          * to indicate this.
 1166          */
 1167         PROC_LOCK(p);
 1168         td->td_oldsigmask = td->td_sigmask;
 1169         td->td_pflags |= TDP_OLDMASK;
 1170         SIG_CANTMASK(mask);
 1171         td->td_sigmask = mask;
 1172         signotify(td);
 1173         while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause", 0) == 0)
 1174                 /* void */;
 1175         PROC_UNLOCK(p);
 1176         /* always return EINTR rather than ERESTART... */
 1177         return (EINTR);
 1178 }
 1179 
 1180 #ifdef COMPAT_43        /* XXX - COMPAT_FBSD3 */
 1181 /*
 1182  * Compatibility sigsuspend call for old binaries.  Note nonstandard calling
 1183  * convention: libc stub passes mask, not pointer, to save a copyin.
 1184  */
 1185 #ifndef _SYS_SYSPROTO_H_
 1186 struct osigsuspend_args {
 1187         osigset_t mask;
 1188 };
 1189 #endif
 1190 /*
 1191  * MPSAFE
 1192  */
 1193 /* ARGSUSED */
 1194 int
 1195 osigsuspend(td, uap)
 1196         struct thread *td;
 1197         struct osigsuspend_args *uap;
 1198 {
 1199         struct proc *p = td->td_proc;
 1200         sigset_t mask;
 1201 
 1202         PROC_LOCK(p);
 1203         td->td_oldsigmask = td->td_sigmask;
 1204         td->td_pflags |= TDP_OLDMASK;
 1205         OSIG2SIG(uap->mask, mask);
 1206         SIG_CANTMASK(mask);
 1207         SIGSETLO(td->td_sigmask, mask);
 1208         signotify(td);
 1209         while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "opause", 0) == 0)
 1210                 /* void */;
 1211         PROC_UNLOCK(p);
 1212         /* always return EINTR rather than ERESTART... */
 1213         return (EINTR);
 1214 }
 1215 #endif /* COMPAT_43 */
 1216 
 1217 #if defined(COMPAT_43)
 1218 #ifndef _SYS_SYSPROTO_H_
 1219 struct osigstack_args {
 1220         struct  sigstack *nss;
 1221         struct  sigstack *oss;
 1222 };
 1223 #endif
 1224 /*
 1225  * MPSAFE
 1226  */
 1227 /* ARGSUSED */
 1228 int
 1229 osigstack(td, uap)
 1230         struct thread *td;
 1231         register struct osigstack_args *uap;
 1232 {
 1233         struct sigstack nss, oss;
 1234         int error = 0;
 1235 
 1236         if (uap->nss != NULL) {
 1237                 error = copyin(uap->nss, &nss, sizeof(nss));
 1238                 if (error)
 1239                         return (error);
 1240         }
 1241         oss.ss_sp = td->td_sigstk.ss_sp;
 1242         oss.ss_onstack = sigonstack(cpu_getstack(td));
 1243         if (uap->nss != NULL) {
 1244                 td->td_sigstk.ss_sp = nss.ss_sp;
 1245                 td->td_sigstk.ss_size = 0;
 1246                 td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK;
 1247                 td->td_pflags |= TDP_ALTSTACK;
 1248         }
 1249         if (uap->oss != NULL)
 1250                 error = copyout(&oss, uap->oss, sizeof(oss));
 1251 
 1252         return (error);
 1253 }
 1254 #endif /* COMPAT_43 */
 1255 
 1256 #ifndef _SYS_SYSPROTO_H_
 1257 struct sigaltstack_args {
 1258         stack_t *ss;
 1259         stack_t *oss;
 1260 };
 1261 #endif
 1262 /*
 1263  * MPSAFE
 1264  */
 1265 /* ARGSUSED */
 1266 int
 1267 sigaltstack(td, uap)
 1268         struct thread *td;
 1269         register struct sigaltstack_args *uap;
 1270 {
 1271         stack_t ss, oss;
 1272         int error;
 1273 
 1274         if (uap->ss != NULL) {
 1275                 error = copyin(uap->ss, &ss, sizeof(ss));
 1276                 if (error)
 1277                         return (error);
 1278         }
 1279         error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL,
 1280             (uap->oss != NULL) ? &oss : NULL);
 1281         if (error)
 1282                 return (error);
 1283         if (uap->oss != NULL)
 1284                 error = copyout(&oss, uap->oss, sizeof(stack_t));
 1285         return (error);
 1286 }
 1287 
 1288 int
 1289 kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss)
 1290 {
 1291         struct proc *p = td->td_proc;
 1292         int oonstack;
 1293 
 1294         oonstack = sigonstack(cpu_getstack(td));
 1295 
 1296         if (oss != NULL) {
 1297                 *oss = td->td_sigstk;
 1298                 oss->ss_flags = (td->td_pflags & TDP_ALTSTACK)
 1299                     ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
 1300         }
 1301 
 1302         if (ss != NULL) {
 1303                 if (oonstack)
 1304                         return (EPERM);
 1305                 if ((ss->ss_flags & ~SS_DISABLE) != 0)
 1306                         return (EINVAL);
 1307                 if (!(ss->ss_flags & SS_DISABLE)) {
 1308                         if (ss->ss_size < p->p_sysent->sv_minsigstksz) {
 1309                                 return (ENOMEM);
 1310                         }
 1311                         td->td_sigstk = *ss;
 1312                         td->td_pflags |= TDP_ALTSTACK;
 1313                 } else {
 1314                         td->td_pflags &= ~TDP_ALTSTACK;
 1315                 }
 1316         }
 1317         return (0);
 1318 }
 1319 
 1320 /*
 1321  * Common code for kill process group/broadcast kill.
 1322  * cp is calling process.
 1323  */
 1324 static int
 1325 killpg1(td, sig, pgid, all)
 1326         register struct thread *td;
 1327         int sig, pgid, all;
 1328 {
 1329         register struct proc *p;
 1330         struct pgrp *pgrp;
 1331         int nfound = 0;
 1332 
 1333         if (all) {
 1334                 /*
 1335                  * broadcast
 1336                  */
 1337                 sx_slock(&allproc_lock);
 1338                 LIST_FOREACH(p, &allproc, p_list) {
 1339                         PROC_LOCK(p);
 1340                         if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
 1341                             p == td->td_proc || p->p_state == PRS_NEW) {
 1342                                 PROC_UNLOCK(p);
 1343                                 continue;
 1344                         }
 1345                         if (p_cansignal(td, p, sig) == 0) {
 1346                                 nfound++;
 1347                                 if (sig)
 1348                                         psignal(p, sig);
 1349                         }
 1350                         PROC_UNLOCK(p);
 1351                 }
 1352                 sx_sunlock(&allproc_lock);
 1353         } else {
 1354                 sx_slock(&proctree_lock);
 1355                 if (pgid == 0) {
 1356                         /*
 1357                          * zero pgid means send to my process group.
 1358                          */
 1359                         pgrp = td->td_proc->p_pgrp;
 1360                         PGRP_LOCK(pgrp);
 1361                 } else {
 1362                         pgrp = pgfind(pgid);
 1363                         if (pgrp == NULL) {
 1364                                 sx_sunlock(&proctree_lock);
 1365                                 return (ESRCH);
 1366                         }
 1367                 }
 1368                 sx_sunlock(&proctree_lock);
 1369                 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
 1370                         PROC_LOCK(p);         
 1371                         if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
 1372                                 p->p_state == PRS_NEW ) {
 1373                                 PROC_UNLOCK(p);
 1374                                 continue;
 1375                         }
 1376                         if (p_cansignal(td, p, sig) == 0) {
 1377                                 nfound++;
 1378                                 if (sig)
 1379                                         psignal(p, sig);
 1380                         }
 1381                         PROC_UNLOCK(p);
 1382                 }
 1383                 PGRP_UNLOCK(pgrp);
 1384         }
 1385         return (nfound ? 0 : ESRCH);
 1386 }
 1387 
 1388 #ifndef _SYS_SYSPROTO_H_
 1389 struct kill_args {
 1390         int     pid;
 1391         int     signum;
 1392 };
 1393 #endif
 1394 /*
 1395  * MPSAFE
 1396  */
 1397 /* ARGSUSED */
 1398 int
 1399 kill(td, uap)
 1400         register struct thread *td;
 1401         register struct kill_args *uap;
 1402 {
 1403         register struct proc *p;
 1404         int error;
 1405 
 1406         AUDIT_ARG(signum, uap->signum);
 1407         AUDIT_ARG(pid, uap->pid);
 1408         if ((u_int)uap->signum > _SIG_MAXSIG)
 1409                 return (EINVAL);
 1410 
 1411         if (uap->pid > 0) {
 1412                 /* kill single process */
 1413                 if ((p = pfind(uap->pid)) == NULL) {
 1414                         if ((p = zpfind(uap->pid)) == NULL)
 1415                                 return (ESRCH);
 1416                 }
 1417                 AUDIT_ARG(process, p);
 1418                 error = p_cansignal(td, p, uap->signum);
 1419                 if (error == 0 && uap->signum)
 1420                         psignal(p, uap->signum);
 1421                 PROC_UNLOCK(p);
 1422                 return (error);
 1423         }
 1424         switch (uap->pid) {
 1425         case -1:                /* broadcast signal */
 1426                 return (killpg1(td, uap->signum, 0, 1));
 1427         case 0:                 /* signal own process group */
 1428                 return (killpg1(td, uap->signum, 0, 0));
 1429         default:                /* negative explicit process group */
 1430                 return (killpg1(td, uap->signum, -uap->pid, 0));
 1431         }
 1432         /* NOTREACHED */
 1433 }
 1434 
 1435 #if defined(COMPAT_43)
 1436 #ifndef _SYS_SYSPROTO_H_
 1437 struct okillpg_args {
 1438         int     pgid;
 1439         int     signum;
 1440 };
 1441 #endif
 1442 /*
 1443  * MPSAFE
 1444  */
 1445 /* ARGSUSED */
 1446 int
 1447 okillpg(td, uap)
 1448         struct thread *td;
 1449         register struct okillpg_args *uap;
 1450 {
 1451 
 1452         AUDIT_ARG(signum, uap->signum);
 1453         AUDIT_ARG(pid, uap->pgid);
 1454         if ((u_int)uap->signum > _SIG_MAXSIG)
 1455                 return (EINVAL);
 1456         return (killpg1(td, uap->signum, uap->pgid, 0));
 1457 }
 1458 #endif /* COMPAT_43 */
 1459 
 1460 /*
 1461  * Send a signal to a process group.
 1462  */
 1463 void
 1464 gsignal(pgid, sig)
 1465         int pgid, sig;
 1466 {
 1467         struct pgrp *pgrp;
 1468 
 1469         if (pgid != 0) {
 1470                 sx_slock(&proctree_lock);
 1471                 pgrp = pgfind(pgid);
 1472                 sx_sunlock(&proctree_lock);
 1473                 if (pgrp != NULL) {
 1474                         pgsignal(pgrp, sig, 0);
 1475                         PGRP_UNLOCK(pgrp);
 1476                 }
 1477         }
 1478 }
 1479 
 1480 /*
 1481  * Send a signal to a process group.  If checktty is 1,
 1482  * limit to members which have a controlling terminal.
 1483  */
 1484 void
 1485 pgsignal(pgrp, sig, checkctty)
 1486         struct pgrp *pgrp;
 1487         int sig, checkctty;
 1488 {
 1489         register struct proc *p;
 1490 
 1491         if (pgrp) {
 1492                 PGRP_LOCK_ASSERT(pgrp, MA_OWNED);
 1493                 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
 1494                         PROC_LOCK(p);
 1495                         if (checkctty == 0 || p->p_flag & P_CONTROLT)
 1496                                 psignal(p, sig);
 1497                         PROC_UNLOCK(p);
 1498                 }
 1499         }
 1500 }
 1501 
 1502 /*
 1503  * Send a signal caused by a trap to the current thread.
 1504  * If it will be caught immediately, deliver it with correct code.
 1505  * Otherwise, post it normally.
 1506  *
 1507  * MPSAFE
 1508  */
 1509 void
 1510 trapsignal(struct thread *td, int sig, u_long code)
 1511 {
 1512         struct sigacts *ps;
 1513         struct proc *p;
 1514         siginfo_t siginfo;
 1515         int error;
 1516 
 1517         p = td->td_proc;
 1518         if (td->td_pflags & TDP_SA) {
 1519                 if (td->td_mailbox == NULL)
 1520                         thread_user_enter(td);
 1521                 PROC_LOCK(p);
 1522                 SIGDELSET(td->td_sigmask, sig);
 1523                 mtx_lock_spin(&sched_lock);
 1524                 /*
 1525                  * Force scheduling an upcall, so UTS has chance to
 1526                  * process the signal before thread runs again in
 1527                  * userland.
 1528                  */
 1529                 if (td->td_upcall)
 1530                         td->td_upcall->ku_flags |= KUF_DOUPCALL;
 1531                 mtx_unlock_spin(&sched_lock);
 1532         } else {
 1533                 PROC_LOCK(p);
 1534         }
 1535         ps = p->p_sigacts;
 1536         mtx_lock(&ps->ps_mtx);
 1537         if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) &&
 1538             !SIGISMEMBER(td->td_sigmask, sig)) {
 1539                 p->p_stats->p_ru.ru_nsignals++;
 1540 #ifdef KTRACE
 1541                 if (KTRPOINT(curthread, KTR_PSIG))
 1542                         ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)],
 1543                             &td->td_sigmask, code);
 1544 #endif
 1545                 if (!(td->td_pflags & TDP_SA))
 1546                         (*p->p_sysent->sv_sendsig)(
 1547                                 ps->ps_sigact[_SIG_IDX(sig)], sig,
 1548                                 &td->td_sigmask, code);
 1549                 else if (td->td_mailbox == NULL) {
 1550                         mtx_unlock(&ps->ps_mtx);
 1551                         /* UTS caused a sync signal */
 1552                         p->p_code = code;       /* XXX for core dump/debugger */
 1553                         p->p_sig = sig;         /* XXX to verify code */
 1554                         sigexit(td, sig);
 1555                 } else {
 1556                         cpu_thread_siginfo(sig, code, &siginfo);
 1557                         mtx_unlock(&ps->ps_mtx);
 1558                         SIGADDSET(td->td_sigmask, sig);
 1559                         PROC_UNLOCK(p);
 1560                         error = copyout(&siginfo, &td->td_mailbox->tm_syncsig,
 1561                             sizeof(siginfo));
 1562                         PROC_LOCK(p);
 1563                         /* UTS memory corrupted */
 1564                         if (error)
 1565                                 sigexit(td, SIGSEGV);
 1566                         mtx_lock(&ps->ps_mtx);
 1567                 }
 1568                 SIGSETOR(td->td_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
 1569                 if (!SIGISMEMBER(ps->ps_signodefer, sig))
 1570                         SIGADDSET(td->td_sigmask, sig);
 1571                 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
 1572                         /*
 1573                          * See kern_sigaction() for origin of this code.
 1574                          */
 1575                         SIGDELSET(ps->ps_sigcatch, sig);
 1576                         if (sig != SIGCONT &&
 1577                             sigprop(sig) & SA_IGNORE)
 1578                                 SIGADDSET(ps->ps_sigignore, sig);
 1579                         ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
 1580                 }
 1581                 mtx_unlock(&ps->ps_mtx);
 1582         } else {
 1583                 mtx_unlock(&ps->ps_mtx);
 1584                 p->p_code = code;       /* XXX for core dump/debugger */
 1585                 p->p_sig = sig;         /* XXX to verify code */
 1586                 tdsignal(td, sig, SIGTARGET_TD);
 1587         }
 1588         PROC_UNLOCK(p);
 1589 }
 1590 
 1591 static struct thread *
 1592 sigtd(struct proc *p, int sig, int prop)
 1593 {
 1594         struct thread *td, *signal_td;
 1595 
 1596         PROC_LOCK_ASSERT(p, MA_OWNED);
 1597 
 1598         /*
 1599          * Check if current thread can handle the signal without
 1600          * switching conetxt to another thread.
 1601          */
 1602         if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig))
 1603                 return (curthread);
 1604         signal_td = NULL;
 1605         mtx_lock_spin(&sched_lock);
 1606         FOREACH_THREAD_IN_PROC(p, td) {
 1607                 if (!SIGISMEMBER(td->td_sigmask, sig)) {
 1608                         signal_td = td;
 1609                         break;
 1610                 }
 1611         }
 1612         if (signal_td == NULL)
 1613                 signal_td = FIRST_THREAD_IN_PROC(p);
 1614         mtx_unlock_spin(&sched_lock);
 1615         return (signal_td);
 1616 }
 1617 
 1618 /*
 1619  * Send the signal to the process.  If the signal has an action, the action
 1620  * is usually performed by the target process rather than the caller; we add
 1621  * the signal to the set of pending signals for the process.
 1622  *
 1623  * Exceptions:
 1624  *   o When a stop signal is sent to a sleeping process that takes the
 1625  *     default action, the process is stopped without awakening it.
 1626  *   o SIGCONT restarts stopped processes (or puts them back to sleep)
 1627  *     regardless of the signal action (eg, blocked or ignored).
 1628  *
 1629  * Other ignored signals are discarded immediately.
 1630  *
 1631  * MPSAFE
 1632  */
 1633 void
 1634 psignal(struct proc *p, int sig)
 1635 {
 1636         struct thread *td;
 1637         int prop;
 1638 
 1639         if (!_SIG_VALID(sig))
 1640                 panic("psignal(): invalid signal");
 1641 
 1642         PROC_LOCK_ASSERT(p, MA_OWNED);
 1643         /*
 1644          * IEEE Std 1003.1-2001: return success when killing a zombie.
 1645          */
 1646         if (p->p_state == PRS_ZOMBIE)
 1647                 return;
 1648         prop = sigprop(sig);
 1649 
 1650         /*
 1651          * Find a thread to deliver the signal to.
 1652          */
 1653         td = sigtd(p, sig, prop);
 1654 
 1655         tdsignal(td, sig, SIGTARGET_P);
 1656 }
 1657 
 1658 /*
 1659  * MPSAFE
 1660  */
 1661 void
 1662 tdsignal(struct thread *td, int sig, sigtarget_t target)
 1663 {
 1664         sigset_t saved;
 1665         struct proc *p = td->td_proc;
 1666 
 1667         if (p->p_flag & P_SA)
 1668                 saved = p->p_siglist;
 1669         do_tdsignal(td, sig, target);
 1670         if ((p->p_flag & P_SA) && !(p->p_flag & P_SIGEVENT)) {
 1671                 if (!SIGSETEQ(saved, p->p_siglist)) {
 1672                         /* pending set changed */
 1673                         p->p_flag |= P_SIGEVENT;
 1674                         wakeup(&p->p_siglist);
 1675                 }
 1676         }
 1677 }
 1678 
 1679 static void
 1680 do_tdsignal(struct thread *td, int sig, sigtarget_t target)
 1681 {
 1682         struct proc *p;
 1683         register sig_t action;
 1684         sigset_t *siglist;
 1685         struct thread *td0;
 1686         register int prop;
 1687         struct sigacts *ps;
 1688         int intrval;
 1689 
 1690         if (!_SIG_VALID(sig))
 1691                 panic("do_tdsignal(): invalid signal");
 1692 
 1693         p = td->td_proc;
 1694         ps = p->p_sigacts;
 1695 
 1696         PROC_LOCK_ASSERT(p, MA_OWNED);
 1697         KNOTE_LOCKED(&p->p_klist, NOTE_SIGNAL | sig);
 1698 
 1699         prop = sigprop(sig);
 1700 
 1701         /*
 1702          * If the signal is blocked and not destined for this thread, then
 1703          * assign it to the process so that we can find it later in the first
 1704          * thread that unblocks it.  Otherwise, assign it to this thread now.
 1705          */
 1706         if (target == SIGTARGET_TD) {
 1707                 siglist = &td->td_siglist;
 1708         } else {
 1709                 if (!SIGISMEMBER(td->td_sigmask, sig))
 1710                         siglist = &td->td_siglist;
 1711                 else
 1712                         siglist = &p->p_siglist;
 1713         }
 1714 
 1715         /*
 1716          * If the signal is being ignored,
 1717          * then we forget about it immediately.
 1718          * (Note: we don't set SIGCONT in ps_sigignore,
 1719          * and if it is set to SIG_IGN,
 1720          * action will be SIG_DFL here.)
 1721          */
 1722         mtx_lock(&ps->ps_mtx);
 1723         if (SIGISMEMBER(ps->ps_sigignore, sig) ||
 1724             (p->p_flag & P_WEXIT)) {
 1725                 mtx_unlock(&ps->ps_mtx);
 1726                 return;
 1727         }
 1728         if (SIGISMEMBER(td->td_sigmask, sig))
 1729                 action = SIG_HOLD;
 1730         else if (SIGISMEMBER(ps->ps_sigcatch, sig))
 1731                 action = SIG_CATCH;
 1732         else
 1733                 action = SIG_DFL;
 1734         if (SIGISMEMBER(ps->ps_sigintr, sig))
 1735                 intrval = EINTR;
 1736         else
 1737                 intrval = ERESTART;
 1738         mtx_unlock(&ps->ps_mtx);
 1739 
 1740         if (prop & SA_CONT) {
 1741                 SIG_STOPSIGMASK(p->p_siglist);
 1742                 /*
 1743                  * XXX Should investigate leaving STOP and CONT sigs only in
 1744                  * the proc's siglist.
 1745                  */
 1746                 mtx_lock_spin(&sched_lock);
 1747                 FOREACH_THREAD_IN_PROC(p, td0)
 1748                         SIG_STOPSIGMASK(td0->td_siglist);
 1749                 mtx_unlock_spin(&sched_lock);
 1750         }
 1751 
 1752         if (prop & SA_STOP) {
 1753                 /*
 1754                  * If sending a tty stop signal to a member of an orphaned
 1755                  * process group, discard the signal here if the action
 1756                  * is default; don't stop the process below if sleeping,
 1757                  * and don't clear any pending SIGCONT.
 1758                  */
 1759                 if ((prop & SA_TTYSTOP) &&
 1760                     (p->p_pgrp->pg_jobc == 0) &&
 1761                     (action == SIG_DFL))
 1762                         return;
 1763                 SIG_CONTSIGMASK(p->p_siglist);
 1764                 mtx_lock_spin(&sched_lock);
 1765                 FOREACH_THREAD_IN_PROC(p, td0)
 1766                         SIG_CONTSIGMASK(td0->td_siglist);
 1767                 mtx_unlock_spin(&sched_lock);
 1768                 p->p_flag &= ~P_CONTINUED;
 1769         }
 1770 
 1771         SIGADDSET(*siglist, sig);
 1772         signotify(td);                  /* uses schedlock */
 1773         /*
 1774          * Defer further processing for signals which are held,
 1775          * except that stopped processes must be continued by SIGCONT.
 1776          */
 1777         if (action == SIG_HOLD &&
 1778             !((prop & SA_CONT) && (p->p_flag & P_STOPPED_SIG)))
 1779                 return;
 1780         /*
 1781          * SIGKILL: Remove procfs STOPEVENTs.
 1782          */
 1783         if (sig == SIGKILL) {
 1784                 /* from procfs_ioctl.c: PIOCBIC */
 1785                 p->p_stops = 0;
 1786                 /* from procfs_ioctl.c: PIOCCONT */
 1787                 p->p_step = 0;
 1788                 wakeup(&p->p_step);
 1789         }
 1790         /*
 1791          * Some signals have a process-wide effect and a per-thread
 1792          * component.  Most processing occurs when the process next
 1793          * tries to cross the user boundary, however there are some
 1794          * times when processing needs to be done immediatly, such as
 1795          * waking up threads so that they can cross the user boundary.
 1796          * We try do the per-process part here.
 1797          */
 1798         if (P_SHOULDSTOP(p)) {
 1799                 /*
 1800                  * The process is in stopped mode. All the threads should be
 1801                  * either winding down or already on the suspended queue.
 1802                  */
 1803                 if (p->p_flag & P_TRACED) {
 1804                         /*
 1805                          * The traced process is already stopped,
 1806                          * so no further action is necessary.
 1807                          * No signal can restart us.
 1808                          */
 1809                         goto out;
 1810                 }
 1811 
 1812                 if (sig == SIGKILL) {
 1813                         /*
 1814                          * SIGKILL sets process running.
 1815                          * It will die elsewhere.
 1816                          * All threads must be restarted.
 1817                          */
 1818                         p->p_flag &= ~P_STOPPED_SIG;
 1819                         goto runfast;
 1820                 }
 1821 
 1822                 if (prop & SA_CONT) {
 1823                         /*
 1824                          * If SIGCONT is default (or ignored), we continue the
 1825                          * process but don't leave the signal in siglist as
 1826                          * it has no further action.  If SIGCONT is held, we
 1827                          * continue the process and leave the signal in
 1828                          * siglist.  If the process catches SIGCONT, let it
 1829                          * handle the signal itself.  If it isn't waiting on
 1830                          * an event, it goes back to run state.
 1831                          * Otherwise, process goes back to sleep state.
 1832                          */
 1833                         p->p_flag &= ~P_STOPPED_SIG;
 1834                         p->p_flag |= P_CONTINUED;
 1835                         if (action == SIG_DFL) {
 1836                                 SIGDELSET(*siglist, sig);
 1837                         } else if (action == SIG_CATCH) {
 1838                                 /*
 1839                                  * The process wants to catch it so it needs
 1840                                  * to run at least one thread, but which one?
 1841                                  * It would seem that the answer would be to
 1842                                  * run an upcall in the next KSE to run, and
 1843                                  * deliver the signal that way. In a NON KSE
 1844                                  * process, we need to make sure that the
 1845                                  * single thread is runnable asap.
 1846                                  * XXXKSE for now however, make them all run.
 1847                                  */
 1848                                 goto runfast;
 1849                         }
 1850                         /*
 1851                          * The signal is not ignored or caught.
 1852                          */
 1853                         mtx_lock_spin(&sched_lock);
 1854                         thread_unsuspend(p);
 1855                         mtx_unlock_spin(&sched_lock);
 1856                         goto out;
 1857                 }
 1858 
 1859                 if (prop & SA_STOP) {
 1860                         /*
 1861                          * Already stopped, don't need to stop again
 1862                          * (If we did the shell could get confused).
 1863                          * Just make sure the signal STOP bit set.
 1864                          */
 1865                         p->p_flag |= P_STOPPED_SIG;
 1866                         SIGDELSET(*siglist, sig);
 1867                         goto out;
 1868                 }
 1869 
 1870                 /*
 1871                  * All other kinds of signals:
 1872                  * If a thread is sleeping interruptibly, simulate a
 1873                  * wakeup so that when it is continued it will be made
 1874                  * runnable and can look at the signal.  However, don't make
 1875                  * the PROCESS runnable, leave it stopped.
 1876                  * It may run a bit until it hits a thread_suspend_check().
 1877                  */
 1878                 mtx_lock_spin(&sched_lock);
 1879                 if (TD_ON_SLEEPQ(td) && (td->td_flags & TDF_SINTR))
 1880                         sleepq_abort(td, intrval);
 1881                 mtx_unlock_spin(&sched_lock);
 1882                 goto out;
 1883                 /*
 1884                  * Mutexes are short lived. Threads waiting on them will
 1885                  * hit thread_suspend_check() soon.
 1886                  */
 1887         } else if (p->p_state == PRS_NORMAL) {
 1888                 if (p->p_flag & P_TRACED || action == SIG_CATCH) {
 1889                         mtx_lock_spin(&sched_lock);
 1890                         tdsigwakeup(td, sig, action, intrval);
 1891                         mtx_unlock_spin(&sched_lock);
 1892                         goto out;
 1893                 }
 1894 
 1895                 MPASS(action == SIG_DFL);
 1896 
 1897                 if (prop & SA_STOP) {
 1898                         if (p->p_flag & P_PPWAIT)
 1899                                 goto out;
 1900                         p->p_flag |= P_STOPPED_SIG;
 1901                         p->p_xstat = sig;
 1902                         mtx_lock_spin(&sched_lock);
 1903                         sig_suspend_threads(td, p, 1);
 1904                         thread_stopped(p);
 1905                         if (p->p_numthreads == p->p_suspcount) {
 1906                                 SIGDELSET(p->p_siglist, p->p_xstat);
 1907                                 FOREACH_THREAD_IN_PROC(p, td0)
 1908                                         SIGDELSET(td0->td_siglist, p->p_xstat);
 1909                         }
 1910                         mtx_unlock_spin(&sched_lock);
 1911                         goto out;
 1912                 } 
 1913                 else
 1914                         goto runfast;
 1915                 /* NOTREACHED */
 1916         } else {
 1917                 /* Not in "NORMAL" state. discard the signal. */
 1918                 SIGDELSET(*siglist, sig);
 1919                 goto out;
 1920         }
 1921 
 1922         /*
 1923          * The process is not stopped so we need to apply the signal to all the
 1924          * running threads.
 1925          */
 1926 
 1927 runfast:
 1928         mtx_lock_spin(&sched_lock);
 1929         tdsigwakeup(td, sig, action, intrval);
 1930         thread_unsuspend(p);
 1931         mtx_unlock_spin(&sched_lock);
 1932 out:
 1933         /* If we jump here, sched_lock should not be owned. */
 1934         mtx_assert(&sched_lock, MA_NOTOWNED);
 1935 }
 1936 
 1937 /*
 1938  * The force of a signal has been directed against a single
 1939  * thread.  We need to see what we can do about knocking it
 1940  * out of any sleep it may be in etc.
 1941  */
 1942 static void
 1943 tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval)
 1944 {
 1945         struct proc *p = td->td_proc;
 1946         register int prop;
 1947 
 1948         PROC_LOCK_ASSERT(p, MA_OWNED);
 1949         mtx_assert(&sched_lock, MA_OWNED);
 1950         prop = sigprop(sig);
 1951 
 1952         /*
 1953          * Bring the priority of a thread up if we want it to get
 1954          * killed in this lifetime.
 1955          */
 1956         if (action == SIG_DFL && (prop & SA_KILL)) {
 1957                 if (p->p_nice > 0)
 1958                         sched_nice(td->td_proc, 0);
 1959                 if (td->td_priority > PUSER)
 1960                         sched_prio(td, PUSER);
 1961         }
 1962 
 1963         if (TD_ON_SLEEPQ(td)) {
 1964                 /*
 1965                  * If thread is sleeping uninterruptibly
 1966                  * we can't interrupt the sleep... the signal will
 1967                  * be noticed when the process returns through
 1968                  * trap() or syscall().
 1969                  */
 1970                 if ((td->td_flags & TDF_SINTR) == 0)
 1971                         return;
 1972                 /*
 1973                  * If SIGCONT is default (or ignored) and process is
 1974                  * asleep, we are finished; the process should not
 1975                  * be awakened.
 1976                  */
 1977                 if ((prop & SA_CONT) && action == SIG_DFL) {
 1978                         SIGDELSET(p->p_siglist, sig);
 1979                         /*
 1980                          * It may be on either list in this state.
 1981                          * Remove from both for now.
 1982                          */
 1983                         SIGDELSET(td->td_siglist, sig);
 1984                         return;
 1985                 }
 1986 
 1987                 /*
 1988                  * Give low priority threads a better chance to run.
 1989                  */
 1990                 if (td->td_priority > PUSER)
 1991                         sched_prio(td, PUSER);
 1992 
 1993                 sleepq_abort(td, intrval);
 1994         } else {
 1995                 /*
 1996                  * Other states do nothing with the signal immediately,
 1997                  * other than kicking ourselves if we are running.
 1998                  * It will either never be noticed, or noticed very soon.
 1999                  */
 2000 #ifdef SMP
 2001                 if (TD_IS_RUNNING(td) && td != curthread)
 2002                         forward_signal(td);
 2003 #endif
 2004         }
 2005 }
 2006 
 2007 static void
 2008 sig_suspend_threads(struct thread *td, struct proc *p, int sending)
 2009 {
 2010         struct thread *td2;
 2011 
 2012         PROC_LOCK_ASSERT(p, MA_OWNED);
 2013         mtx_assert(&sched_lock, MA_OWNED);
 2014 
 2015         FOREACH_THREAD_IN_PROC(p, td2) {
 2016                 if ((TD_IS_SLEEPING(td2) || TD_IS_SWAPPED(td2)) &&
 2017                     (td2->td_flags & TDF_SINTR) &&
 2018                     !TD_IS_SUSPENDED(td2)) {
 2019                         thread_suspend_one(td2);
 2020                 } else {
 2021                         if (sending || td != td2)
 2022                                 td2->td_flags |= TDF_ASTPENDING;
 2023 #ifdef SMP
 2024                         if (TD_IS_RUNNING(td2) && td2 != td)
 2025                                 forward_signal(td2);
 2026 #endif
 2027                 }
 2028         }
 2029 }
 2030 
 2031 int
 2032 ptracestop(struct thread *td, int sig)
 2033 {
 2034         struct proc *p = td->td_proc;
 2035 
 2036         PROC_LOCK_ASSERT(p, MA_OWNED);
 2037         WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
 2038             &p->p_mtx.mtx_object, "Stopping for traced signal");
 2039 
 2040         mtx_lock_spin(&sched_lock);
 2041         td->td_flags |= TDF_XSIG;
 2042         mtx_unlock_spin(&sched_lock);
 2043         td->td_xsig = sig;
 2044         while ((p->p_flag & P_TRACED) && (td->td_flags & TDF_XSIG)) {
 2045                 if (p->p_flag & P_SINGLE_EXIT) {
 2046                         mtx_lock_spin(&sched_lock);
 2047                         td->td_flags &= ~TDF_XSIG;
 2048                         mtx_unlock_spin(&sched_lock);
 2049                         return (sig);
 2050                 }
 2051                 /*
 2052                  * Just make wait() to work, the last stopped thread
 2053                  * will win.
 2054                  */
 2055                 p->p_xstat = sig;
 2056                 p->p_xthread = td;
 2057                 p->p_flag |= (P_STOPPED_SIG|P_STOPPED_TRACE);
 2058                 mtx_lock_spin(&sched_lock);
 2059                 sig_suspend_threads(td, p, 0);
 2060 stopme:
 2061                 thread_stopped(p);
 2062                 thread_suspend_one(td);
 2063                 PROC_UNLOCK(p);
 2064                 DROP_GIANT();
 2065                 mi_switch(SW_VOL, NULL);
 2066                 mtx_unlock_spin(&sched_lock);
 2067                 PICKUP_GIANT();
 2068                 PROC_LOCK(p);
 2069                 if (!(p->p_flag & P_TRACED))
 2070                         break;
 2071                 if (td->td_flags & TDF_DBSUSPEND) {
 2072                         if (p->p_flag & P_SINGLE_EXIT)
 2073                                 break;
 2074                         mtx_lock_spin(&sched_lock);
 2075                         goto stopme;
 2076                 }
 2077         }
 2078         return (td->td_xsig);
 2079 }
 2080 
 2081 /*
 2082  * If the current process has received a signal (should be caught or cause
 2083  * termination, should interrupt current syscall), return the signal number.
 2084  * Stop signals with default action are processed immediately, then cleared;
 2085  * they aren't returned.  This is checked after each entry to the system for
 2086  * a syscall or trap (though this can usually be done without calling issignal
 2087  * by checking the pending signal masks in cursig.) The normal call
 2088  * sequence is
 2089  *
 2090  *      while (sig = cursig(curthread))
 2091  *              postsig(sig);
 2092  */
 2093 static int
 2094 issignal(td)
 2095         struct thread *td;
 2096 {
 2097         struct proc *p;
 2098         struct sigacts *ps;
 2099         sigset_t sigpending;
 2100         int sig, prop, newsig;
 2101 
 2102         p = td->td_proc;
 2103         ps = p->p_sigacts;
 2104         mtx_assert(&ps->ps_mtx, MA_OWNED);
 2105         PROC_LOCK_ASSERT(p, MA_OWNED);
 2106         for (;;) {
 2107                 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
 2108 
 2109                 sigpending = td->td_siglist;
 2110                 SIGSETNAND(sigpending, td->td_sigmask);
 2111 
 2112                 if (p->p_flag & P_PPWAIT)
 2113                         SIG_STOPSIGMASK(sigpending);
 2114                 if (SIGISEMPTY(sigpending))     /* no signal to send */
 2115                         return (0);
 2116                 sig = sig_ffs(&sigpending);
 2117 
 2118                 if (p->p_stops & S_SIG) {
 2119                         mtx_unlock(&ps->ps_mtx);
 2120                         stopevent(p, S_SIG, sig);
 2121                         mtx_lock(&ps->ps_mtx);
 2122                 }
 2123 
 2124                 /*
 2125                  * We should see pending but ignored signals
 2126                  * only if P_TRACED was on when they were posted.
 2127                  */
 2128                 if (SIGISMEMBER(ps->ps_sigignore, sig) && (traced == 0)) {
 2129                         SIGDELSET(td->td_siglist, sig);
 2130                         if (td->td_pflags & TDP_SA)
 2131                                 SIGADDSET(td->td_sigmask, sig);
 2132                         continue;
 2133                 }
 2134                 if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) {
 2135                         /*
 2136                          * If traced, always stop.
 2137                          */
 2138                         mtx_unlock(&ps->ps_mtx);
 2139                         newsig = ptracestop(td, sig);
 2140                         mtx_lock(&ps->ps_mtx);
 2141 
 2142                         /*
 2143                          * If parent wants us to take the signal,
 2144                          * then it will leave it in p->p_xstat;
 2145                          * otherwise we just look for signals again.
 2146                          */
 2147                         SIGDELSET(td->td_siglist, sig); /* clear old signal */
 2148                         if (td->td_pflags & TDP_SA)
 2149                                 SIGADDSET(td->td_sigmask, sig);
 2150                         if (newsig == 0)
 2151                                 continue;
 2152                         sig = newsig;
 2153                         /*
 2154                          * If the traced bit got turned off, go back up
 2155                          * to the top to rescan signals.  This ensures
 2156                          * that p_sig* and p_sigact are consistent.
 2157                          */
 2158                         if ((p->p_flag & P_TRACED) == 0)
 2159                                 continue;
 2160 
 2161                         /*
 2162                          * Put the new signal into td_siglist.  If the
 2163                          * signal is being masked, look for other signals.
 2164                          */
 2165                         SIGADDSET(td->td_siglist, sig);
 2166                         if (td->td_pflags & TDP_SA)
 2167                                 SIGDELSET(td->td_sigmask, sig);
 2168                         if (SIGISMEMBER(td->td_sigmask, sig))
 2169                                 continue;
 2170                         signotify(td);
 2171                 }
 2172 
 2173                 prop = sigprop(sig);
 2174 
 2175                 /*
 2176                  * Decide whether the signal should be returned.
 2177                  * Return the signal's number, or fall through
 2178                  * to clear it from the pending mask.
 2179                  */
 2180                 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
 2181 
 2182                 case (intptr_t)SIG_DFL:
 2183                         /*
 2184                          * Don't take default actions on system processes.
 2185                          */
 2186                         if (p->p_pid <= 1) {
 2187 #ifdef DIAGNOSTIC
 2188                                 /*
 2189                                  * Are you sure you want to ignore SIGSEGV
 2190                                  * in init? XXX
 2191                                  */
 2192                                 printf("Process (pid %lu) got signal %d\n",
 2193                                         (u_long)p->p_pid, sig);
 2194 #endif
 2195                                 break;          /* == ignore */
 2196                         }
 2197                         /*
 2198                          * If there is a pending stop signal to process
 2199                          * with default action, stop here,
 2200                          * then clear the signal.  However,
 2201                          * if process is member of an orphaned
 2202                          * process group, ignore tty stop signals.
 2203                          */
 2204                         if (prop & SA_STOP) {
 2205                                 if (p->p_flag & P_TRACED ||
 2206                                     (p->p_pgrp->pg_jobc == 0 &&
 2207                                      prop & SA_TTYSTOP))
 2208                                         break;  /* == ignore */
 2209                                 mtx_unlock(&ps->ps_mtx);
 2210                                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
 2211                                     &p->p_mtx.mtx_object, "Catching SIGSTOP");
 2212                                 p->p_flag |= P_STOPPED_SIG;
 2213                                 p->p_xstat = sig;
 2214                                 mtx_lock_spin(&sched_lock);
 2215                                 sig_suspend_threads(td, p, 0);
 2216                                 thread_stopped(p);
 2217                                 thread_suspend_one(td);
 2218                                 PROC_UNLOCK(p);
 2219                                 DROP_GIANT();
 2220                                 mi_switch(SW_INVOL, NULL);
 2221                                 mtx_unlock_spin(&sched_lock);
 2222                                 PICKUP_GIANT();
 2223                                 PROC_LOCK(p);
 2224                                 mtx_lock(&ps->ps_mtx);
 2225                                 break;
 2226                         } else if (prop & SA_IGNORE) {
 2227                                 /*
 2228                                  * Except for SIGCONT, shouldn't get here.
 2229                                  * Default action is to ignore; drop it.
 2230                                  */
 2231                                 break;          /* == ignore */
 2232                         } else
 2233                                 return (sig);
 2234                         /*NOTREACHED*/
 2235 
 2236                 case (intptr_t)SIG_IGN:
 2237                         /*
 2238                          * Masking above should prevent us ever trying
 2239                          * to take action on an ignored signal other
 2240                          * than SIGCONT, unless process is traced.
 2241                          */
 2242                         if ((prop & SA_CONT) == 0 &&
 2243                             (p->p_flag & P_TRACED) == 0)
 2244                                 printf("issignal\n");
 2245                         break;          /* == ignore */
 2246 
 2247                 default:
 2248                         /*
 2249                          * This signal has an action, let
 2250                          * postsig() process it.
 2251                          */
 2252                         return (sig);
 2253                 }
 2254                 SIGDELSET(td->td_siglist, sig);         /* take the signal! */
 2255         }
 2256         /* NOTREACHED */
 2257 }
 2258 
 2259 /*
 2260  * MPSAFE
 2261  */
 2262 void
 2263 thread_stopped(struct proc *p)
 2264 {
 2265         struct proc *p1 = curthread->td_proc;
 2266         struct sigacts *ps;
 2267         int n;
 2268 
 2269         PROC_LOCK_ASSERT(p, MA_OWNED);
 2270         mtx_assert(&sched_lock, MA_OWNED);
 2271         n = p->p_suspcount;
 2272         if (p == p1)
 2273                 n++;
 2274         if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) {
 2275                 mtx_unlock_spin(&sched_lock);
 2276                 p->p_flag &= ~P_WAITED;
 2277                 PROC_LOCK(p->p_pptr);
 2278                 /*
 2279                  * Wake up parent sleeping in kern_wait(), also send
 2280                  * SIGCHLD to parent, but SIGCHLD does not guarantee
 2281                  * that parent will awake, because parent may masked
 2282                  * the signal.
 2283                  */
 2284                 p->p_pptr->p_flag |= P_STATCHILD;
 2285                 wakeup(p->p_pptr);
 2286                 ps = p->p_pptr->p_sigacts;
 2287                 mtx_lock(&ps->ps_mtx);
 2288                 if ((ps->ps_flag & PS_NOCLDSTOP) == 0) {
 2289                         mtx_unlock(&ps->ps_mtx);
 2290                         psignal(p->p_pptr, SIGCHLD);
 2291                 } else
 2292                         mtx_unlock(&ps->ps_mtx);
 2293                 PROC_UNLOCK(p->p_pptr);
 2294                 mtx_lock_spin(&sched_lock);
 2295         }
 2296 }
 2297  
 2298 /*
 2299  * Take the action for the specified signal
 2300  * from the current set of pending signals.
 2301  */
 2302 void
 2303 postsig(sig)
 2304         register int sig;
 2305 {
 2306         struct thread *td = curthread;
 2307         register struct proc *p = td->td_proc;
 2308         struct sigacts *ps;
 2309         sig_t action;
 2310         sigset_t returnmask;
 2311         int code;
 2312 
 2313         KASSERT(sig != 0, ("postsig"));
 2314 
 2315         PROC_LOCK_ASSERT(p, MA_OWNED);
 2316         ps = p->p_sigacts;
 2317         mtx_assert(&ps->ps_mtx, MA_OWNED);
 2318         SIGDELSET(td->td_siglist, sig);
 2319         action = ps->ps_sigact[_SIG_IDX(sig)];
 2320 #ifdef KTRACE
 2321         if (KTRPOINT(td, KTR_PSIG))
 2322                 ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ?
 2323                     &td->td_oldsigmask : &td->td_sigmask, 0);
 2324 #endif
 2325         if (p->p_stops & S_SIG) {
 2326                 mtx_unlock(&ps->ps_mtx);
 2327                 stopevent(p, S_SIG, sig);
 2328                 mtx_lock(&ps->ps_mtx);
 2329         }
 2330 
 2331         if (!(td->td_pflags & TDP_SA) && action == SIG_DFL) {
 2332                 /*
 2333                  * Default action, where the default is to kill
 2334                  * the process.  (Other cases were ignored above.)
 2335                  */
 2336                 mtx_unlock(&ps->ps_mtx);
 2337                 sigexit(td, sig);
 2338                 /* NOTREACHED */
 2339         } else {
 2340                 if (td->td_pflags & TDP_SA) {
 2341                         if (sig == SIGKILL) {
 2342                                 mtx_unlock(&ps->ps_mtx);
 2343                                 sigexit(td, sig);
 2344                         }
 2345                 }
 2346 
 2347                 /*
 2348                  * If we get here, the signal must be caught.
 2349                  */
 2350                 KASSERT(action != SIG_IGN && !SIGISMEMBER(td->td_sigmask, sig),
 2351                     ("postsig action"));
 2352                 /*
 2353                  * Set the new mask value and also defer further
 2354                  * occurrences of this signal.
 2355                  *
 2356                  * Special case: user has done a sigsuspend.  Here the
 2357                  * current mask is not of interest, but rather the
 2358                  * mask from before the sigsuspend is what we want
 2359                  * restored after the signal processing is completed.
 2360                  */
 2361                 if (td->td_pflags & TDP_OLDMASK) {
 2362                         returnmask = td->td_oldsigmask;
 2363                         td->td_pflags &= ~TDP_OLDMASK;
 2364                 } else
 2365                         returnmask = td->td_sigmask;
 2366 
 2367                 SIGSETOR(td->td_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
 2368                 if (!SIGISMEMBER(ps->ps_signodefer, sig))
 2369                         SIGADDSET(td->td_sigmask, sig);
 2370 
 2371                 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
 2372                         /*
 2373                          * See kern_sigaction() for origin of this code.
 2374                          */
 2375                         SIGDELSET(ps->ps_sigcatch, sig);
 2376                         if (sig != SIGCONT &&
 2377                             sigprop(sig) & SA_IGNORE)
 2378                                 SIGADDSET(ps->ps_sigignore, sig);
 2379                         ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
 2380                 }
 2381                 p->p_stats->p_ru.ru_nsignals++;
 2382                 if (p->p_sig != sig) {
 2383                         code = 0;
 2384                 } else {
 2385                         code = p->p_code;
 2386                         p->p_code = 0;
 2387                         p->p_sig = 0;
 2388                 }
 2389                 if (td->td_pflags & TDP_SA)
 2390                         thread_signal_add(curthread, sig);
 2391                 else
 2392                         (*p->p_sysent->sv_sendsig)(action, sig,
 2393                             &returnmask, code);
 2394         }
 2395 }
 2396 
 2397 /*
 2398  * Kill the current process for stated reason.
 2399  */
 2400 void
 2401 killproc(p, why)
 2402         struct proc *p;
 2403         char *why;
 2404 {
 2405 
 2406         PROC_LOCK_ASSERT(p, MA_OWNED);
 2407         CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)",
 2408                 p, p->p_pid, p->p_comm);
 2409         log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm,
 2410                 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
 2411         p->p_flag |= P_WKILLED;
 2412         psignal(p, SIGKILL);
 2413 }
 2414 
 2415 /*
 2416  * Force the current process to exit with the specified signal, dumping core
 2417  * if appropriate.  We bypass the normal tests for masked and caught signals,
 2418  * allowing unrecoverable failures to terminate the process without changing
 2419  * signal state.  Mark the accounting record with the signal termination.
 2420  * If dumping core, save the signal number for the debugger.  Calls exit and
 2421  * does not return.
 2422  *
 2423  * MPSAFE
 2424  */
 2425 void
 2426 sigexit(td, sig)
 2427         struct thread *td;
 2428         int sig;
 2429 {
 2430         struct proc *p = td->td_proc;
 2431 
 2432         PROC_LOCK_ASSERT(p, MA_OWNED);
 2433         p->p_acflag |= AXSIG;
 2434         /*
 2435          * We must be single-threading to generate a core dump.  This
 2436          * ensures that the registers in the core file are up-to-date.
 2437          * Also, the ELF dump handler assumes that the thread list doesn't
 2438          * change out from under it.
 2439          *
 2440          * XXX If another thread attempts to single-thread before us
 2441          *     (e.g. via fork()), we won't get a dump at all.
 2442          */
 2443         if ((sigprop(sig) & SA_CORE) && (thread_single(SINGLE_NO_EXIT) == 0)) {
 2444                 p->p_sig = sig;
 2445                 /*
 2446                  * Log signals which would cause core dumps
 2447                  * (Log as LOG_INFO to appease those who don't want
 2448                  * these messages.)
 2449                  * XXX : Todo, as well as euid, write out ruid too
 2450                  * Note that coredump() drops proc lock.
 2451                  */
 2452                 if (coredump(td) == 0)
 2453                         sig |= WCOREFLAG;
 2454                 if (kern_logsigexit)
 2455                         log(LOG_INFO,
 2456                             "pid %d (%s), uid %d: exited on signal %d%s\n",
 2457                             p->p_pid, p->p_comm,
 2458                             td->td_ucred ? td->td_ucred->cr_uid : -1,
 2459                             sig &~ WCOREFLAG,
 2460                             sig & WCOREFLAG ? " (core dumped)" : "");
 2461         } else
 2462                 PROC_UNLOCK(p);
 2463         exit1(td, W_EXITCODE(0, sig));
 2464         /* NOTREACHED */
 2465 }
 2466 
 2467 static char corefilename[MAXPATHLEN] = {"%N.core"};
 2468 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
 2469               sizeof(corefilename), "process corefile name format string");
 2470 
 2471 /*
 2472  * expand_name(name, uid, pid)
 2473  * Expand the name described in corefilename, using name, uid, and pid.
 2474  * corefilename is a printf-like string, with three format specifiers:
 2475  *      %N      name of process ("name")
 2476  *      %P      process id (pid)
 2477  *      %U      user id (uid)
 2478  * For example, "%N.core" is the default; they can be disabled completely
 2479  * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
 2480  * This is controlled by the sysctl variable kern.corefile (see above).
 2481  */
 2482 
 2483 static char *
 2484 expand_name(name, uid, pid)
 2485         const char *name;
 2486         uid_t uid;
 2487         pid_t pid;
 2488 {
 2489         const char *format, *appendstr;
 2490         char *temp;
 2491         char buf[11];           /* Buffer for pid/uid -- max 4B */
 2492         size_t i, l, n;
 2493 
 2494         format = corefilename;
 2495         temp = malloc(MAXPATHLEN, M_TEMP, M_NOWAIT | M_ZERO);
 2496         if (temp == NULL)
 2497                 return (NULL);
 2498         for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
 2499                 switch (format[i]) {
 2500                 case '%':       /* Format character */
 2501                         i++;
 2502                         switch (format[i]) {
 2503                         case '%':
 2504                                 appendstr = "%";
 2505                                 break;
 2506                         case 'N':       /* process name */
 2507                                 appendstr = name;
 2508                                 break;
 2509                         case 'P':       /* process id */
 2510                                 sprintf(buf, "%u", pid);
 2511                                 appendstr = buf;
 2512                                 break;
 2513                         case 'U':       /* user id */
 2514                                 sprintf(buf, "%u", uid);
 2515                                 appendstr = buf;
 2516                                 break;
 2517                         default:
 2518                                 appendstr = "";
 2519                                 log(LOG_ERR,
 2520                                     "Unknown format character %c in `%s'\n",
 2521                                     format[i], format);
 2522                         }
 2523                         l = strlen(appendstr);
 2524                         if ((n + l) >= MAXPATHLEN)
 2525                                 goto toolong;
 2526                         memcpy(temp + n, appendstr, l);
 2527                         n += l;
 2528                         break;
 2529                 default:
 2530                         temp[n++] = format[i];
 2531                 }
 2532         }
 2533         if (format[i] != '\0')
 2534                 goto toolong;
 2535         return (temp);
 2536 toolong:
 2537         log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too long\n",
 2538             (long)pid, name, (u_long)uid);
 2539         free(temp, M_TEMP);
 2540         return (NULL);
 2541 }
 2542 
 2543 /*
 2544  * Dump a process' core.  The main routine does some
 2545  * policy checking, and creates the name of the coredump;
 2546  * then it passes on a vnode and a size limit to the process-specific
 2547  * coredump routine if there is one; if there _is not_ one, it returns
 2548  * ENOSYS; otherwise it returns the error from the process-specific routine.
 2549  */
 2550 
 2551 static int
 2552 coredump(struct thread *td)
 2553 {
 2554         struct proc *p = td->td_proc;
 2555         register struct vnode *vp;
 2556         register struct ucred *cred = td->td_ucred;
 2557         struct flock lf;
 2558         struct nameidata nd;
 2559         struct vattr vattr;
 2560         int error, error1, flags, locked;
 2561         struct mount *mp;
 2562         char *name;                     /* name of corefile */
 2563         off_t limit;
 2564 
 2565         PROC_LOCK_ASSERT(p, MA_OWNED);
 2566         MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td);
 2567         _STOPEVENT(p, S_CORE, 0);
 2568 
 2569         if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) {
 2570                 PROC_UNLOCK(p);
 2571                 return (EFAULT);
 2572         }
 2573         
 2574         /*
 2575          * Note that the bulk of limit checking is done after
 2576          * the corefile is created.  The exception is if the limit
 2577          * for corefiles is 0, in which case we don't bother
 2578          * creating the corefile at all.  This layout means that
 2579          * a corefile is truncated instead of not being created,
 2580          * if it is larger than the limit.
 2581          */
 2582         limit = (off_t)lim_cur(p, RLIMIT_CORE);
 2583         PROC_UNLOCK(p);
 2584         if (limit == 0)
 2585                 return (EFBIG);
 2586 
 2587         mtx_lock(&Giant);
 2588 restart:
 2589         name = expand_name(p->p_comm, td->td_ucred->cr_uid, p->p_pid);
 2590         if (name == NULL) {
 2591                 mtx_unlock(&Giant);
 2592                 return (EINVAL);
 2593         }
 2594         NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td); /* XXXKSE */
 2595         flags = O_CREAT | FWRITE | O_NOFOLLOW;
 2596         error = vn_open(&nd, &flags, S_IRUSR | S_IWUSR, -1);
 2597         free(name, M_TEMP);
 2598         if (error) {
 2599                 mtx_unlock(&Giant);             
 2600                 return (error);
 2601         }
 2602         NDFREE(&nd, NDF_ONLY_PNBUF);
 2603         vp = nd.ni_vp;
 2604 
 2605         /* Don't dump to non-regular files or files with links. */
 2606         if (vp->v_type != VREG ||
 2607             VOP_GETATTR(vp, &vattr, cred, td) || vattr.va_nlink != 1) {
 2608                 VOP_UNLOCK(vp, 0, td);
 2609                 error = EFAULT;
 2610                 goto out;
 2611         }
 2612 
 2613         VOP_UNLOCK(vp, 0, td);
 2614         lf.l_whence = SEEK_SET;
 2615         lf.l_start = 0;
 2616         lf.l_len = 0;
 2617         lf.l_type = F_WRLCK;
 2618         locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0);
 2619 
 2620         if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
 2621                 lf.l_type = F_UNLCK;
 2622                 if (locked)
 2623                         VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
 2624                 if ((error = vn_close(vp, FWRITE, cred, td)) != 0)
 2625                         return (error);
 2626                 if ((error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH)) != 0)
 2627                         return (error);
 2628                 goto restart;
 2629         }
 2630 
 2631         VATTR_NULL(&vattr);
 2632         vattr.va_size = 0;
 2633         if (set_core_nodump_flag)
 2634                 vattr.va_flags = UF_NODUMP;
 2635         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
 2636         VOP_LEASE(vp, td, cred, LEASE_WRITE);
 2637         VOP_SETATTR(vp, &vattr, cred, td);
 2638         VOP_UNLOCK(vp, 0, td);
 2639         vn_finished_write(mp);
 2640         PROC_LOCK(p);
 2641         p->p_acflag |= ACORE;
 2642         PROC_UNLOCK(p);
 2643 
 2644         error = p->p_sysent->sv_coredump ?
 2645           p->p_sysent->sv_coredump(td, vp, limit) :
 2646           ENOSYS;
 2647 
 2648         if (locked) {
 2649                 lf.l_type = F_UNLCK;
 2650                 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
 2651         }
 2652 out:
 2653         error1 = vn_close(vp, FWRITE, cred, td);
 2654         mtx_unlock(&Giant);
 2655         if (error == 0)
 2656                 error = error1;
 2657         return (error);
 2658 }
 2659 
 2660 /*
 2661  * Nonexistent system call-- signal process (may want to handle it).
 2662  * Flag error in case process won't see signal immediately (blocked or ignored).
 2663  */
 2664 #ifndef _SYS_SYSPROTO_H_
 2665 struct nosys_args {
 2666         int     dummy;
 2667 };
 2668 #endif
 2669 /*
 2670  * MPSAFE
 2671  */
 2672 /* ARGSUSED */
 2673 int
 2674 nosys(td, args)
 2675         struct thread *td;
 2676         struct nosys_args *args;
 2677 {
 2678         struct proc *p = td->td_proc;
 2679 
 2680         PROC_LOCK(p);
 2681         psignal(p, SIGSYS);
 2682         PROC_UNLOCK(p);
 2683         return (ENOSYS);
 2684 }
 2685 
 2686 /*
 2687  * Send a SIGIO or SIGURG signal to a process or process group using
 2688  * stored credentials rather than those of the current process.
 2689  */
 2690 void
 2691 pgsigio(sigiop, sig, checkctty)
 2692         struct sigio **sigiop;
 2693         int sig, checkctty;
 2694 {
 2695         struct sigio *sigio;
 2696 
 2697         SIGIO_LOCK();
 2698         sigio = *sigiop;
 2699         if (sigio == NULL) {
 2700                 SIGIO_UNLOCK();
 2701                 return;
 2702         }
 2703         if (sigio->sio_pgid > 0) {
 2704                 PROC_LOCK(sigio->sio_proc);
 2705                 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred))
 2706                         psignal(sigio->sio_proc, sig);
 2707                 PROC_UNLOCK(sigio->sio_proc);
 2708         } else if (sigio->sio_pgid < 0) {
 2709                 struct proc *p;
 2710 
 2711                 PGRP_LOCK(sigio->sio_pgrp);
 2712                 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
 2713                         PROC_LOCK(p);
 2714                         if (CANSIGIO(sigio->sio_ucred, p->p_ucred) &&
 2715                             (checkctty == 0 || (p->p_flag & P_CONTROLT)))
 2716                                 psignal(p, sig);
 2717                         PROC_UNLOCK(p);
 2718                 }
 2719                 PGRP_UNLOCK(sigio->sio_pgrp);
 2720         }
 2721         SIGIO_UNLOCK();
 2722 }
 2723 
 2724 static int
 2725 filt_sigattach(struct knote *kn)
 2726 {
 2727         struct proc *p = curproc;
 2728 
 2729         kn->kn_ptr.p_proc = p;
 2730         kn->kn_flags |= EV_CLEAR;               /* automatically set */
 2731 
 2732         knlist_add(&p->p_klist, kn, 0);
 2733 
 2734         return (0);
 2735 }
 2736 
 2737 static void
 2738 filt_sigdetach(struct knote *kn)
 2739 {
 2740         struct proc *p = kn->kn_ptr.p_proc;
 2741 
 2742         knlist_remove(&p->p_klist, kn, 0);
 2743 }
 2744 
 2745 /*
 2746  * signal knotes are shared with proc knotes, so we apply a mask to 
 2747  * the hint in order to differentiate them from process hints.  This
 2748  * could be avoided by using a signal-specific knote list, but probably
 2749  * isn't worth the trouble.
 2750  */
 2751 static int
 2752 filt_signal(struct knote *kn, long hint)
 2753 {
 2754 
 2755         if (hint & NOTE_SIGNAL) {
 2756                 hint &= ~NOTE_SIGNAL;
 2757 
 2758                 if (kn->kn_id == hint)
 2759                         kn->kn_data++;
 2760         }
 2761         return (kn->kn_data != 0);
 2762 }
 2763 
 2764 struct sigacts *
 2765 sigacts_alloc(void)
 2766 {
 2767         struct sigacts *ps;
 2768 
 2769         ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO);
 2770         ps->ps_refcnt = 1;
 2771         mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF);
 2772         return (ps);
 2773 }
 2774 
 2775 void
 2776 sigacts_free(struct sigacts *ps)
 2777 {
 2778 
 2779         mtx_lock(&ps->ps_mtx);
 2780         ps->ps_refcnt--;
 2781         if (ps->ps_refcnt == 0) {
 2782                 mtx_destroy(&ps->ps_mtx);
 2783                 free(ps, M_SUBPROC);
 2784         } else
 2785                 mtx_unlock(&ps->ps_mtx);
 2786 }
 2787 
 2788 struct sigacts *
 2789 sigacts_hold(struct sigacts *ps)
 2790 {
 2791         mtx_lock(&ps->ps_mtx);
 2792         ps->ps_refcnt++;
 2793         mtx_unlock(&ps->ps_mtx);
 2794         return (ps);
 2795 }
 2796 
 2797 void
 2798 sigacts_copy(struct sigacts *dest, struct sigacts *src)
 2799 {
 2800 
 2801         KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest"));
 2802         mtx_lock(&src->ps_mtx);
 2803         bcopy(src, dest, offsetof(struct sigacts, ps_refcnt));
 2804         mtx_unlock(&src->ps_mtx);
 2805 }
 2806 
 2807 int
 2808 sigacts_shared(struct sigacts *ps)
 2809 {
 2810         int shared;
 2811 
 2812         mtx_lock(&ps->ps_mtx);
 2813         shared = ps->ps_refcnt > 1;
 2814         mtx_unlock(&ps->ps_mtx);
 2815         return (shared);
 2816 }

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