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/10/sys/kern/kern_sig.c 322848 2017-08-24 17:25:16Z will $");
   39 
   40 #include "opt_compat.h"
   41 #include "opt_kdtrace.h"
   42 #include "opt_ktrace.h"
   43 #include "opt_core.h"
   44 #include "opt_procdesc.h"
   45 
   46 #include <sys/param.h>
   47 #include <sys/ctype.h>
   48 #include <sys/systm.h>
   49 #include <sys/signalvar.h>
   50 #include <sys/vnode.h>
   51 #include <sys/acct.h>
   52 #include <sys/bus.h>
   53 #include <sys/capsicum.h>
   54 #include <sys/condvar.h>
   55 #include <sys/event.h>
   56 #include <sys/fcntl.h>
   57 #include <sys/imgact.h>
   58 #include <sys/kernel.h>
   59 #include <sys/ktr.h>
   60 #include <sys/ktrace.h>
   61 #include <sys/lock.h>
   62 #include <sys/malloc.h>
   63 #include <sys/mutex.h>
   64 #include <sys/refcount.h>
   65 #include <sys/namei.h>
   66 #include <sys/proc.h>
   67 #include <sys/procdesc.h>
   68 #include <sys/posix4.h>
   69 #include <sys/pioctl.h>
   70 #include <sys/racct.h>
   71 #include <sys/resourcevar.h>
   72 #include <sys/sdt.h>
   73 #include <sys/sbuf.h>
   74 #include <sys/sleepqueue.h>
   75 #include <sys/smp.h>
   76 #include <sys/stat.h>
   77 #include <sys/sx.h>
   78 #include <sys/syscallsubr.h>
   79 #include <sys/sysctl.h>
   80 #include <sys/sysent.h>
   81 #include <sys/syslog.h>
   82 #include <sys/sysproto.h>
   83 #include <sys/timers.h>
   84 #include <sys/unistd.h>
   85 #include <sys/wait.h>
   86 #include <vm/vm.h>
   87 #include <vm/vm_extern.h>
   88 #include <vm/uma.h>
   89 
   90 #include <sys/jail.h>
   91 
   92 #include <machine/cpu.h>
   93 
   94 #include <security/audit/audit.h>
   95 
   96 #define ONSIG   32              /* NSIG for osig* syscalls.  XXX. */
   97 
   98 SDT_PROVIDER_DECLARE(proc);
   99 SDT_PROBE_DEFINE3(proc, , , signal__send,
  100     "struct thread *", "struct proc *", "int");
  101 SDT_PROBE_DEFINE2(proc, , , signal__clear,
  102     "int", "ksiginfo_t *");
  103 SDT_PROBE_DEFINE3(proc, , , signal__discard,
  104     "struct thread *", "struct proc *", "int");
  105 
  106 static int      coredump(struct thread *);
  107 static int      killpg1(struct thread *td, int sig, int pgid, int all,
  108                     ksiginfo_t *ksi);
  109 static int      issignal(struct thread *td);
  110 static int      sigprop(int sig);
  111 static void     tdsigwakeup(struct thread *, int, sig_t, int);
  112 static void     sig_suspend_threads(struct thread *, struct proc *, int);
  113 static int      filt_sigattach(struct knote *kn);
  114 static void     filt_sigdetach(struct knote *kn);
  115 static int      filt_signal(struct knote *kn, long hint);
  116 static struct thread *sigtd(struct proc *p, int sig, int prop);
  117 static void     sigqueue_start(void);
  118 
  119 static uma_zone_t       ksiginfo_zone = NULL;
  120 struct filterops sig_filtops = {
  121         .f_isfd = 0,
  122         .f_attach = filt_sigattach,
  123         .f_detach = filt_sigdetach,
  124         .f_event = filt_signal,
  125 };
  126 
  127 static int      kern_logsigexit = 1;
  128 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
  129     &kern_logsigexit, 0,
  130     "Log processes quitting on abnormal signals to syslog(3)");
  131 
  132 static int      kern_forcesigexit = 1;
  133 SYSCTL_INT(_kern, OID_AUTO, forcesigexit, CTLFLAG_RW,
  134     &kern_forcesigexit, 0, "Force trap signal to be handled");
  135 
  136 static SYSCTL_NODE(_kern, OID_AUTO, sigqueue, CTLFLAG_RW, 0,
  137     "POSIX real time signal");
  138 
  139 static int      max_pending_per_proc = 128;
  140 SYSCTL_INT(_kern_sigqueue, OID_AUTO, max_pending_per_proc, CTLFLAG_RW,
  141     &max_pending_per_proc, 0, "Max pending signals per proc");
  142 
  143 static int      preallocate_siginfo = 1024;
  144 TUNABLE_INT("kern.sigqueue.preallocate", &preallocate_siginfo);
  145 SYSCTL_INT(_kern_sigqueue, OID_AUTO, preallocate, CTLFLAG_RD,
  146     &preallocate_siginfo, 0, "Preallocated signal memory size");
  147 
  148 static int      signal_overflow = 0;
  149 SYSCTL_INT(_kern_sigqueue, OID_AUTO, overflow, CTLFLAG_RD,
  150     &signal_overflow, 0, "Number of signals overflew");
  151 
  152 static int      signal_alloc_fail = 0;
  153 SYSCTL_INT(_kern_sigqueue, OID_AUTO, alloc_fail, CTLFLAG_RD,
  154     &signal_alloc_fail, 0, "signals failed to be allocated");
  155 
  156 SYSINIT(signal, SI_SUB_P1003_1B, SI_ORDER_FIRST+3, sigqueue_start, NULL);
  157 
  158 /*
  159  * Policy -- Can ucred cr1 send SIGIO to process cr2?
  160  * Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG
  161  * in the right situations.
  162  */
  163 #define CANSIGIO(cr1, cr2) \
  164         ((cr1)->cr_uid == 0 || \
  165             (cr1)->cr_ruid == (cr2)->cr_ruid || \
  166             (cr1)->cr_uid == (cr2)->cr_ruid || \
  167             (cr1)->cr_ruid == (cr2)->cr_uid || \
  168             (cr1)->cr_uid == (cr2)->cr_uid)
  169 
  170 static int      sugid_coredump;
  171 TUNABLE_INT("kern.sugid_coredump", &sugid_coredump);
  172 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW,
  173     &sugid_coredump, 0, "Allow setuid and setgid processes to dump core");
  174 
  175 static int      capmode_coredump;
  176 TUNABLE_INT("kern.capmode_coredump", &capmode_coredump);
  177 SYSCTL_INT(_kern, OID_AUTO, capmode_coredump, CTLFLAG_RW,
  178     &capmode_coredump, 0, "Allow processes in capability mode to dump core");
  179 
  180 static int      do_coredump = 1;
  181 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
  182         &do_coredump, 0, "Enable/Disable coredumps");
  183 
  184 static int      set_core_nodump_flag = 0;
  185 SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag,
  186         0, "Enable setting the NODUMP flag on coredump files");
  187 
  188 static int      coredump_devctl = 0;
  189 SYSCTL_INT(_kern, OID_AUTO, coredump_devctl, CTLFLAG_RW, &coredump_devctl,
  190         0, "Generate a devctl notification when processes coredump");
  191 
  192 /*
  193  * Signal properties and actions.
  194  * The array below categorizes the signals and their default actions
  195  * according to the following properties:
  196  */
  197 #define SA_KILL         0x01            /* terminates process by default */
  198 #define SA_CORE         0x02            /* ditto and coredumps */
  199 #define SA_STOP         0x04            /* suspend process */
  200 #define SA_TTYSTOP      0x08            /* ditto, from tty */
  201 #define SA_IGNORE       0x10            /* ignore by default */
  202 #define SA_CONT         0x20            /* continue if suspended */
  203 #define SA_CANTMASK     0x40            /* non-maskable, catchable */
  204 
  205 static int sigproptbl[NSIG] = {
  206         SA_KILL,                        /* SIGHUP */
  207         SA_KILL,                        /* SIGINT */
  208         SA_KILL|SA_CORE,                /* SIGQUIT */
  209         SA_KILL|SA_CORE,                /* SIGILL */
  210         SA_KILL|SA_CORE,                /* SIGTRAP */
  211         SA_KILL|SA_CORE,                /* SIGABRT */
  212         SA_KILL|SA_CORE,                /* SIGEMT */
  213         SA_KILL|SA_CORE,                /* SIGFPE */
  214         SA_KILL,                        /* SIGKILL */
  215         SA_KILL|SA_CORE,                /* SIGBUS */
  216         SA_KILL|SA_CORE,                /* SIGSEGV */
  217         SA_KILL|SA_CORE,                /* SIGSYS */
  218         SA_KILL,                        /* SIGPIPE */
  219         SA_KILL,                        /* SIGALRM */
  220         SA_KILL,                        /* SIGTERM */
  221         SA_IGNORE,                      /* SIGURG */
  222         SA_STOP,                        /* SIGSTOP */
  223         SA_STOP|SA_TTYSTOP,             /* SIGTSTP */
  224         SA_IGNORE|SA_CONT,              /* SIGCONT */
  225         SA_IGNORE,                      /* SIGCHLD */
  226         SA_STOP|SA_TTYSTOP,             /* SIGTTIN */
  227         SA_STOP|SA_TTYSTOP,             /* SIGTTOU */
  228         SA_IGNORE,                      /* SIGIO */
  229         SA_KILL,                        /* SIGXCPU */
  230         SA_KILL,                        /* SIGXFSZ */
  231         SA_KILL,                        /* SIGVTALRM */
  232         SA_KILL,                        /* SIGPROF */
  233         SA_IGNORE,                      /* SIGWINCH  */
  234         SA_IGNORE,                      /* SIGINFO */
  235         SA_KILL,                        /* SIGUSR1 */
  236         SA_KILL,                        /* SIGUSR2 */
  237 };
  238 
  239 static void reschedule_signals(struct proc *p, sigset_t block, int flags);
  240 
  241 static void
  242 sigqueue_start(void)
  243 {
  244         ksiginfo_zone = uma_zcreate("ksiginfo", sizeof(ksiginfo_t),
  245                 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
  246         uma_prealloc(ksiginfo_zone, preallocate_siginfo);
  247         p31b_setcfg(CTL_P1003_1B_REALTIME_SIGNALS, _POSIX_REALTIME_SIGNALS);
  248         p31b_setcfg(CTL_P1003_1B_RTSIG_MAX, SIGRTMAX - SIGRTMIN + 1);
  249         p31b_setcfg(CTL_P1003_1B_SIGQUEUE_MAX, max_pending_per_proc);
  250 }
  251 
  252 ksiginfo_t *
  253 ksiginfo_alloc(int wait)
  254 {
  255         int flags;
  256 
  257         flags = M_ZERO;
  258         if (! wait)
  259                 flags |= M_NOWAIT;
  260         if (ksiginfo_zone != NULL)
  261                 return ((ksiginfo_t *)uma_zalloc(ksiginfo_zone, flags));
  262         return (NULL);
  263 }
  264 
  265 void
  266 ksiginfo_free(ksiginfo_t *ksi)
  267 {
  268         uma_zfree(ksiginfo_zone, ksi);
  269 }
  270 
  271 static __inline int
  272 ksiginfo_tryfree(ksiginfo_t *ksi)
  273 {
  274         if (!(ksi->ksi_flags & KSI_EXT)) {
  275                 uma_zfree(ksiginfo_zone, ksi);
  276                 return (1);
  277         }
  278         return (0);
  279 }
  280 
  281 void
  282 sigqueue_init(sigqueue_t *list, struct proc *p)
  283 {
  284         SIGEMPTYSET(list->sq_signals);
  285         SIGEMPTYSET(list->sq_kill);
  286         SIGEMPTYSET(list->sq_ptrace);
  287         TAILQ_INIT(&list->sq_list);
  288         list->sq_proc = p;
  289         list->sq_flags = SQ_INIT;
  290 }
  291 
  292 /*
  293  * Get a signal's ksiginfo.
  294  * Return:
  295  *      0       -       signal not found
  296  *      others  -       signal number
  297  */
  298 static int
  299 sigqueue_get(sigqueue_t *sq, int signo, ksiginfo_t *si)
  300 {
  301         struct proc *p = sq->sq_proc;
  302         struct ksiginfo *ksi, *next;
  303         int count = 0;
  304 
  305         KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
  306 
  307         if (!SIGISMEMBER(sq->sq_signals, signo))
  308                 return (0);
  309 
  310         if (SIGISMEMBER(sq->sq_ptrace, signo)) {
  311                 count++;
  312                 SIGDELSET(sq->sq_ptrace, signo);
  313                 si->ksi_flags |= KSI_PTRACE;
  314         }
  315         if (SIGISMEMBER(sq->sq_kill, signo)) {
  316                 count++;
  317                 if (count == 1)
  318                         SIGDELSET(sq->sq_kill, signo);
  319         }
  320 
  321         TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
  322                 if (ksi->ksi_signo == signo) {
  323                         if (count == 0) {
  324                                 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
  325                                 ksi->ksi_sigq = NULL;
  326                                 ksiginfo_copy(ksi, si);
  327                                 if (ksiginfo_tryfree(ksi) && p != NULL)
  328                                         p->p_pendingcnt--;
  329                         }
  330                         if (++count > 1)
  331                                 break;
  332                 }
  333         }
  334 
  335         if (count <= 1)
  336                 SIGDELSET(sq->sq_signals, signo);
  337         si->ksi_signo = signo;
  338         return (signo);
  339 }
  340 
  341 void
  342 sigqueue_take(ksiginfo_t *ksi)
  343 {
  344         struct ksiginfo *kp;
  345         struct proc     *p;
  346         sigqueue_t      *sq;
  347 
  348         if (ksi == NULL || (sq = ksi->ksi_sigq) == NULL)
  349                 return;
  350 
  351         p = sq->sq_proc;
  352         TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
  353         ksi->ksi_sigq = NULL;
  354         if (!(ksi->ksi_flags & KSI_EXT) && p != NULL)
  355                 p->p_pendingcnt--;
  356 
  357         for (kp = TAILQ_FIRST(&sq->sq_list); kp != NULL;
  358              kp = TAILQ_NEXT(kp, ksi_link)) {
  359                 if (kp->ksi_signo == ksi->ksi_signo)
  360                         break;
  361         }
  362         if (kp == NULL && !SIGISMEMBER(sq->sq_kill, ksi->ksi_signo) &&
  363             !SIGISMEMBER(sq->sq_ptrace, ksi->ksi_signo))
  364                 SIGDELSET(sq->sq_signals, ksi->ksi_signo);
  365 }
  366 
  367 static int
  368 sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si)
  369 {
  370         struct proc *p = sq->sq_proc;
  371         struct ksiginfo *ksi;
  372         int ret = 0;
  373 
  374         KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
  375 
  376         /*
  377          * SIGKILL/SIGSTOP cannot be caught or masked, so take the fast path
  378          * for these signals.
  379          */
  380         if (signo == SIGKILL || signo == SIGSTOP || si == NULL) {
  381                 SIGADDSET(sq->sq_kill, signo);
  382                 goto out_set_bit;
  383         }
  384 
  385         /* directly insert the ksi, don't copy it */
  386         if (si->ksi_flags & KSI_INS) {
  387                 if (si->ksi_flags & KSI_HEAD)
  388                         TAILQ_INSERT_HEAD(&sq->sq_list, si, ksi_link);
  389                 else
  390                         TAILQ_INSERT_TAIL(&sq->sq_list, si, ksi_link);
  391                 si->ksi_sigq = sq;
  392                 goto out_set_bit;
  393         }
  394 
  395         if (__predict_false(ksiginfo_zone == NULL)) {
  396                 SIGADDSET(sq->sq_kill, signo);
  397                 goto out_set_bit;
  398         }
  399 
  400         if (p != NULL && p->p_pendingcnt >= max_pending_per_proc) {
  401                 signal_overflow++;
  402                 ret = EAGAIN;
  403         } else if ((ksi = ksiginfo_alloc(0)) == NULL) {
  404                 signal_alloc_fail++;
  405                 ret = EAGAIN;
  406         } else {
  407                 if (p != NULL)
  408                         p->p_pendingcnt++;
  409                 ksiginfo_copy(si, ksi);
  410                 ksi->ksi_signo = signo;
  411                 if (si->ksi_flags & KSI_HEAD)
  412                         TAILQ_INSERT_HEAD(&sq->sq_list, ksi, ksi_link);
  413                 else
  414                         TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link);
  415                 ksi->ksi_sigq = sq;
  416         }
  417 
  418         if (ret != 0) {
  419                 if ((si->ksi_flags & KSI_PTRACE) != 0) {
  420                         SIGADDSET(sq->sq_ptrace, signo);
  421                         ret = 0;
  422                         goto out_set_bit;
  423                 } else if ((si->ksi_flags & KSI_TRAP) != 0 ||
  424                     (si->ksi_flags & KSI_SIGQ) == 0) {
  425                         SIGADDSET(sq->sq_kill, signo);
  426                         ret = 0;
  427                         goto out_set_bit;
  428                 }
  429                 return (ret);
  430         }
  431 
  432 out_set_bit:
  433         SIGADDSET(sq->sq_signals, signo);
  434         return (ret);
  435 }
  436 
  437 void
  438 sigqueue_flush(sigqueue_t *sq)
  439 {
  440         struct proc *p = sq->sq_proc;
  441         ksiginfo_t *ksi;
  442 
  443         KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited"));
  444 
  445         if (p != NULL)
  446                 PROC_LOCK_ASSERT(p, MA_OWNED);
  447 
  448         while ((ksi = TAILQ_FIRST(&sq->sq_list)) != NULL) {
  449                 TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
  450                 ksi->ksi_sigq = NULL;
  451                 if (ksiginfo_tryfree(ksi) && p != NULL)
  452                         p->p_pendingcnt--;
  453         }
  454 
  455         SIGEMPTYSET(sq->sq_signals);
  456         SIGEMPTYSET(sq->sq_kill);
  457         SIGEMPTYSET(sq->sq_ptrace);
  458 }
  459 
  460 static void
  461 sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, const sigset_t *set)
  462 {
  463         sigset_t tmp;
  464         struct proc *p1, *p2;
  465         ksiginfo_t *ksi, *next;
  466 
  467         KASSERT(src->sq_flags & SQ_INIT, ("src sigqueue not inited"));
  468         KASSERT(dst->sq_flags & SQ_INIT, ("dst sigqueue not inited"));
  469         p1 = src->sq_proc;
  470         p2 = dst->sq_proc;
  471         /* Move siginfo to target list */
  472         TAILQ_FOREACH_SAFE(ksi, &src->sq_list, ksi_link, next) {
  473                 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
  474                         TAILQ_REMOVE(&src->sq_list, ksi, ksi_link);
  475                         if (p1 != NULL)
  476                                 p1->p_pendingcnt--;
  477                         TAILQ_INSERT_TAIL(&dst->sq_list, ksi, ksi_link);
  478                         ksi->ksi_sigq = dst;
  479                         if (p2 != NULL)
  480                                 p2->p_pendingcnt++;
  481                 }
  482         }
  483 
  484         /* Move pending bits to target list */
  485         tmp = src->sq_kill;
  486         SIGSETAND(tmp, *set);
  487         SIGSETOR(dst->sq_kill, tmp);
  488         SIGSETNAND(src->sq_kill, tmp);
  489 
  490         tmp = src->sq_ptrace;
  491         SIGSETAND(tmp, *set);
  492         SIGSETOR(dst->sq_ptrace, tmp);
  493         SIGSETNAND(src->sq_ptrace, tmp);
  494 
  495         tmp = src->sq_signals;
  496         SIGSETAND(tmp, *set);
  497         SIGSETOR(dst->sq_signals, tmp);
  498         SIGSETNAND(src->sq_signals, tmp);
  499 }
  500 
  501 #if 0
  502 static void
  503 sigqueue_move(sigqueue_t *src, sigqueue_t *dst, int signo)
  504 {
  505         sigset_t set;
  506 
  507         SIGEMPTYSET(set);
  508         SIGADDSET(set, signo);
  509         sigqueue_move_set(src, dst, &set);
  510 }
  511 #endif
  512 
  513 static void
  514 sigqueue_delete_set(sigqueue_t *sq, const sigset_t *set)
  515 {
  516         struct proc *p = sq->sq_proc;
  517         ksiginfo_t *ksi, *next;
  518 
  519         KASSERT(sq->sq_flags & SQ_INIT, ("src sigqueue not inited"));
  520 
  521         /* Remove siginfo queue */
  522         TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) {
  523                 if (SIGISMEMBER(*set, ksi->ksi_signo)) {
  524                         TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link);
  525                         ksi->ksi_sigq = NULL;
  526                         if (ksiginfo_tryfree(ksi) && p != NULL)
  527                                 p->p_pendingcnt--;
  528                 }
  529         }
  530         SIGSETNAND(sq->sq_kill, *set);
  531         SIGSETNAND(sq->sq_ptrace, *set);
  532         SIGSETNAND(sq->sq_signals, *set);
  533 }
  534 
  535 void
  536 sigqueue_delete(sigqueue_t *sq, int signo)
  537 {
  538         sigset_t set;
  539 
  540         SIGEMPTYSET(set);
  541         SIGADDSET(set, signo);
  542         sigqueue_delete_set(sq, &set);
  543 }
  544 
  545 /* Remove a set of signals for a process */
  546 static void
  547 sigqueue_delete_set_proc(struct proc *p, const sigset_t *set)
  548 {
  549         sigqueue_t worklist;
  550         struct thread *td0;
  551 
  552         PROC_LOCK_ASSERT(p, MA_OWNED);
  553 
  554         sigqueue_init(&worklist, NULL);
  555         sigqueue_move_set(&p->p_sigqueue, &worklist, set);
  556 
  557         FOREACH_THREAD_IN_PROC(p, td0)
  558                 sigqueue_move_set(&td0->td_sigqueue, &worklist, set);
  559 
  560         sigqueue_flush(&worklist);
  561 }
  562 
  563 void
  564 sigqueue_delete_proc(struct proc *p, int signo)
  565 {
  566         sigset_t set;
  567 
  568         SIGEMPTYSET(set);
  569         SIGADDSET(set, signo);
  570         sigqueue_delete_set_proc(p, &set);
  571 }
  572 
  573 static void
  574 sigqueue_delete_stopmask_proc(struct proc *p)
  575 {
  576         sigset_t set;
  577 
  578         SIGEMPTYSET(set);
  579         SIGADDSET(set, SIGSTOP);
  580         SIGADDSET(set, SIGTSTP);
  581         SIGADDSET(set, SIGTTIN);
  582         SIGADDSET(set, SIGTTOU);
  583         sigqueue_delete_set_proc(p, &set);
  584 }
  585 
  586 /*
  587  * Determine signal that should be delivered to thread td, the current
  588  * thread, 0 if none.  If there is a pending stop signal with default
  589  * action, the process stops in issignal().
  590  */
  591 int
  592 cursig(struct thread *td)
  593 {
  594         PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
  595         mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED);
  596         THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
  597         return (SIGPENDING(td) ? issignal(td) : 0);
  598 }
  599 
  600 /*
  601  * Arrange for ast() to handle unmasked pending signals on return to user
  602  * mode.  This must be called whenever a signal is added to td_sigqueue or
  603  * unmasked in td_sigmask.
  604  */
  605 void
  606 signotify(struct thread *td)
  607 {
  608         struct proc *p;
  609 
  610         p = td->td_proc;
  611 
  612         PROC_LOCK_ASSERT(p, MA_OWNED);
  613 
  614         if (SIGPENDING(td)) {
  615                 thread_lock(td);
  616                 td->td_flags |= TDF_NEEDSIGCHK | TDF_ASTPENDING;
  617                 thread_unlock(td);
  618         }
  619 }
  620 
  621 int
  622 sigonstack(size_t sp)
  623 {
  624         struct thread *td = curthread;
  625 
  626         return ((td->td_pflags & TDP_ALTSTACK) ?
  627 #if defined(COMPAT_43)
  628             ((td->td_sigstk.ss_size == 0) ?
  629                 (td->td_sigstk.ss_flags & SS_ONSTACK) :
  630                 ((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size))
  631 #else
  632             ((sp - (size_t)td->td_sigstk.ss_sp) < td->td_sigstk.ss_size)
  633 #endif
  634             : 0);
  635 }
  636 
  637 static __inline int
  638 sigprop(int sig)
  639 {
  640 
  641         if (sig > 0 && sig < NSIG)
  642                 return (sigproptbl[_SIG_IDX(sig)]);
  643         return (0);
  644 }
  645 
  646 int
  647 sig_ffs(sigset_t *set)
  648 {
  649         int i;
  650 
  651         for (i = 0; i < _SIG_WORDS; i++)
  652                 if (set->__bits[i])
  653                         return (ffs(set->__bits[i]) + (i * 32));
  654         return (0);
  655 }
  656 
  657 static bool
  658 sigact_flag_test(struct sigaction *act, int flag)
  659 {
  660 
  661         /*
  662          * SA_SIGINFO is reset when signal disposition is set to
  663          * ignore or default.  Other flags are kept according to user
  664          * settings.
  665          */
  666         return ((act->sa_flags & flag) != 0 && (flag != SA_SIGINFO ||
  667             ((__sighandler_t *)act->sa_sigaction != SIG_IGN &&
  668             (__sighandler_t *)act->sa_sigaction != SIG_DFL)));
  669 }
  670 
  671 /*
  672  * kern_sigaction
  673  * sigaction
  674  * freebsd4_sigaction
  675  * osigaction
  676  */
  677 int
  678 kern_sigaction(td, sig, act, oact, flags)
  679         struct thread *td;
  680         register int sig;
  681         struct sigaction *act, *oact;
  682         int flags;
  683 {
  684         struct sigacts *ps;
  685         struct proc *p = td->td_proc;
  686 
  687         if (!_SIG_VALID(sig))
  688                 return (EINVAL);
  689         if (act != NULL && act->sa_handler != SIG_DFL &&
  690             act->sa_handler != SIG_IGN && (act->sa_flags & ~(SA_ONSTACK |
  691             SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER |
  692             SA_NOCLDWAIT | SA_SIGINFO)) != 0)
  693                 return (EINVAL);
  694 
  695         PROC_LOCK(p);
  696         ps = p->p_sigacts;
  697         mtx_lock(&ps->ps_mtx);
  698         if (oact) {
  699                 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
  700                 oact->sa_flags = 0;
  701                 if (SIGISMEMBER(ps->ps_sigonstack, sig))
  702                         oact->sa_flags |= SA_ONSTACK;
  703                 if (!SIGISMEMBER(ps->ps_sigintr, sig))
  704                         oact->sa_flags |= SA_RESTART;
  705                 if (SIGISMEMBER(ps->ps_sigreset, sig))
  706                         oact->sa_flags |= SA_RESETHAND;
  707                 if (SIGISMEMBER(ps->ps_signodefer, sig))
  708                         oact->sa_flags |= SA_NODEFER;
  709                 if (SIGISMEMBER(ps->ps_siginfo, sig)) {
  710                         oact->sa_flags |= SA_SIGINFO;
  711                         oact->sa_sigaction =
  712                             (__siginfohandler_t *)ps->ps_sigact[_SIG_IDX(sig)];
  713                 } else
  714                         oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
  715                 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDSTOP)
  716                         oact->sa_flags |= SA_NOCLDSTOP;
  717                 if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDWAIT)
  718                         oact->sa_flags |= SA_NOCLDWAIT;
  719         }
  720         if (act) {
  721                 if ((sig == SIGKILL || sig == SIGSTOP) &&
  722                     act->sa_handler != SIG_DFL) {
  723                         mtx_unlock(&ps->ps_mtx);
  724                         PROC_UNLOCK(p);
  725                         return (EINVAL);
  726                 }
  727 
  728                 /*
  729                  * Change setting atomically.
  730                  */
  731 
  732                 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
  733                 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
  734                 if (sigact_flag_test(act, SA_SIGINFO)) {
  735                         ps->ps_sigact[_SIG_IDX(sig)] =
  736                             (__sighandler_t *)act->sa_sigaction;
  737                         SIGADDSET(ps->ps_siginfo, sig);
  738                 } else {
  739                         ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
  740                         SIGDELSET(ps->ps_siginfo, sig);
  741                 }
  742                 if (!sigact_flag_test(act, SA_RESTART))
  743                         SIGADDSET(ps->ps_sigintr, sig);
  744                 else
  745                         SIGDELSET(ps->ps_sigintr, sig);
  746                 if (sigact_flag_test(act, SA_ONSTACK))
  747                         SIGADDSET(ps->ps_sigonstack, sig);
  748                 else
  749                         SIGDELSET(ps->ps_sigonstack, sig);
  750                 if (sigact_flag_test(act, SA_RESETHAND))
  751                         SIGADDSET(ps->ps_sigreset, sig);
  752                 else
  753                         SIGDELSET(ps->ps_sigreset, sig);
  754                 if (sigact_flag_test(act, SA_NODEFER))
  755                         SIGADDSET(ps->ps_signodefer, sig);
  756                 else
  757                         SIGDELSET(ps->ps_signodefer, sig);
  758                 if (sig == SIGCHLD) {
  759                         if (act->sa_flags & SA_NOCLDSTOP)
  760                                 ps->ps_flag |= PS_NOCLDSTOP;
  761                         else
  762                                 ps->ps_flag &= ~PS_NOCLDSTOP;
  763                         if (act->sa_flags & SA_NOCLDWAIT) {
  764                                 /*
  765                                  * Paranoia: since SA_NOCLDWAIT is implemented
  766                                  * by reparenting the dying child to PID 1 (and
  767                                  * trust it to reap the zombie), PID 1 itself
  768                                  * is forbidden to set SA_NOCLDWAIT.
  769                                  */
  770                                 if (p->p_pid == 1)
  771                                         ps->ps_flag &= ~PS_NOCLDWAIT;
  772                                 else
  773                                         ps->ps_flag |= PS_NOCLDWAIT;
  774                         } else
  775                                 ps->ps_flag &= ~PS_NOCLDWAIT;
  776                         if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
  777                                 ps->ps_flag |= PS_CLDSIGIGN;
  778                         else
  779                                 ps->ps_flag &= ~PS_CLDSIGIGN;
  780                 }
  781                 /*
  782                  * Set bit in ps_sigignore for signals that are set to SIG_IGN,
  783                  * and for signals set to SIG_DFL where the default is to
  784                  * ignore. However, don't put SIGCONT in ps_sigignore, as we
  785                  * have to restart the process.
  786                  */
  787                 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
  788                     (sigprop(sig) & SA_IGNORE &&
  789                      ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
  790                         /* never to be seen again */
  791                         sigqueue_delete_proc(p, sig);
  792                         if (sig != SIGCONT)
  793                                 /* easier in psignal */
  794                                 SIGADDSET(ps->ps_sigignore, sig);
  795                         SIGDELSET(ps->ps_sigcatch, sig);
  796                 } else {
  797                         SIGDELSET(ps->ps_sigignore, sig);
  798                         if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
  799                                 SIGDELSET(ps->ps_sigcatch, sig);
  800                         else
  801                                 SIGADDSET(ps->ps_sigcatch, sig);
  802                 }
  803 #ifdef COMPAT_FREEBSD4
  804                 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
  805                     ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
  806                     (flags & KSA_FREEBSD4) == 0)
  807                         SIGDELSET(ps->ps_freebsd4, sig);
  808                 else
  809                         SIGADDSET(ps->ps_freebsd4, sig);
  810 #endif
  811 #ifdef COMPAT_43
  812                 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
  813                     ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL ||
  814                     (flags & KSA_OSIGSET) == 0)
  815                         SIGDELSET(ps->ps_osigset, sig);
  816                 else
  817                         SIGADDSET(ps->ps_osigset, sig);
  818 #endif
  819         }
  820         mtx_unlock(&ps->ps_mtx);
  821         PROC_UNLOCK(p);
  822         return (0);
  823 }
  824 
  825 #ifndef _SYS_SYSPROTO_H_
  826 struct sigaction_args {
  827         int     sig;
  828         struct  sigaction *act;
  829         struct  sigaction *oact;
  830 };
  831 #endif
  832 int
  833 sys_sigaction(td, uap)
  834         struct thread *td;
  835         register struct sigaction_args *uap;
  836 {
  837         struct sigaction act, oact;
  838         register struct sigaction *actp, *oactp;
  839         int error;
  840 
  841         actp = (uap->act != NULL) ? &act : NULL;
  842         oactp = (uap->oact != NULL) ? &oact : NULL;
  843         if (actp) {
  844                 error = copyin(uap->act, actp, sizeof(act));
  845                 if (error)
  846                         return (error);
  847         }
  848         error = kern_sigaction(td, uap->sig, actp, oactp, 0);
  849         if (oactp && !error)
  850                 error = copyout(oactp, uap->oact, sizeof(oact));
  851         return (error);
  852 }
  853 
  854 #ifdef COMPAT_FREEBSD4
  855 #ifndef _SYS_SYSPROTO_H_
  856 struct freebsd4_sigaction_args {
  857         int     sig;
  858         struct  sigaction *act;
  859         struct  sigaction *oact;
  860 };
  861 #endif
  862 int
  863 freebsd4_sigaction(td, uap)
  864         struct thread *td;
  865         register struct freebsd4_sigaction_args *uap;
  866 {
  867         struct sigaction act, oact;
  868         register struct sigaction *actp, *oactp;
  869         int error;
  870 
  871 
  872         actp = (uap->act != NULL) ? &act : NULL;
  873         oactp = (uap->oact != NULL) ? &oact : NULL;
  874         if (actp) {
  875                 error = copyin(uap->act, actp, sizeof(act));
  876                 if (error)
  877                         return (error);
  878         }
  879         error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4);
  880         if (oactp && !error)
  881                 error = copyout(oactp, uap->oact, sizeof(oact));
  882         return (error);
  883 }
  884 #endif  /* COMAPT_FREEBSD4 */
  885 
  886 #ifdef COMPAT_43        /* XXX - COMPAT_FBSD3 */
  887 #ifndef _SYS_SYSPROTO_H_
  888 struct osigaction_args {
  889         int     signum;
  890         struct  osigaction *nsa;
  891         struct  osigaction *osa;
  892 };
  893 #endif
  894 int
  895 osigaction(td, uap)
  896         struct thread *td;
  897         register struct osigaction_args *uap;
  898 {
  899         struct osigaction sa;
  900         struct sigaction nsa, osa;
  901         register struct sigaction *nsap, *osap;
  902         int error;
  903 
  904         if (uap->signum <= 0 || uap->signum >= ONSIG)
  905                 return (EINVAL);
  906 
  907         nsap = (uap->nsa != NULL) ? &nsa : NULL;
  908         osap = (uap->osa != NULL) ? &osa : NULL;
  909 
  910         if (nsap) {
  911                 error = copyin(uap->nsa, &sa, sizeof(sa));
  912                 if (error)
  913                         return (error);
  914                 nsap->sa_handler = sa.sa_handler;
  915                 nsap->sa_flags = sa.sa_flags;
  916                 OSIG2SIG(sa.sa_mask, nsap->sa_mask);
  917         }
  918         error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
  919         if (osap && !error) {
  920                 sa.sa_handler = osap->sa_handler;
  921                 sa.sa_flags = osap->sa_flags;
  922                 SIG2OSIG(osap->sa_mask, sa.sa_mask);
  923                 error = copyout(&sa, uap->osa, sizeof(sa));
  924         }
  925         return (error);
  926 }
  927 
  928 #if !defined(__i386__)
  929 /* Avoid replicating the same stub everywhere */
  930 int
  931 osigreturn(td, uap)
  932         struct thread *td;
  933         struct osigreturn_args *uap;
  934 {
  935 
  936         return (nosys(td, (struct nosys_args *)uap));
  937 }
  938 #endif
  939 #endif /* COMPAT_43 */
  940 
  941 /*
  942  * Initialize signal state for process 0;
  943  * set to ignore signals that are ignored by default.
  944  */
  945 void
  946 siginit(p)
  947         struct proc *p;
  948 {
  949         register int i;
  950         struct sigacts *ps;
  951 
  952         PROC_LOCK(p);
  953         ps = p->p_sigacts;
  954         mtx_lock(&ps->ps_mtx);
  955         for (i = 1; i <= NSIG; i++) {
  956                 if (sigprop(i) & SA_IGNORE && i != SIGCONT) {
  957                         SIGADDSET(ps->ps_sigignore, i);
  958                 }
  959         }
  960         mtx_unlock(&ps->ps_mtx);
  961         PROC_UNLOCK(p);
  962 }
  963 
  964 /*
  965  * Reset specified signal to the default disposition.
  966  */
  967 static void
  968 sigdflt(struct sigacts *ps, int sig)
  969 {
  970 
  971         mtx_assert(&ps->ps_mtx, MA_OWNED);
  972         SIGDELSET(ps->ps_sigcatch, sig);
  973         if ((sigprop(sig) & SA_IGNORE) != 0 && sig != SIGCONT)
  974                 SIGADDSET(ps->ps_sigignore, sig);
  975         ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
  976         SIGDELSET(ps->ps_siginfo, sig);
  977 }
  978 
  979 /*
  980  * Reset signals for an exec of the specified process.
  981  */
  982 void
  983 execsigs(struct proc *p)
  984 {
  985         struct sigacts *ps;
  986         int sig;
  987         struct thread *td;
  988 
  989         /*
  990          * Reset caught signals.  Held signals remain held
  991          * through td_sigmask (unless they were caught,
  992          * and are now ignored by default).
  993          */
  994         PROC_LOCK_ASSERT(p, MA_OWNED);
  995         ps = p->p_sigacts;
  996         mtx_lock(&ps->ps_mtx);
  997         while (SIGNOTEMPTY(ps->ps_sigcatch)) {
  998                 sig = sig_ffs(&ps->ps_sigcatch);
  999                 sigdflt(ps, sig);
 1000                 if ((sigprop(sig) & SA_IGNORE) != 0)
 1001                         sigqueue_delete_proc(p, sig);
 1002         }
 1003         /*
 1004          * Reset stack state to the user stack.
 1005          * Clear set of signals caught on the signal stack.
 1006          */
 1007         td = curthread;
 1008         MPASS(td->td_proc == p);
 1009         td->td_sigstk.ss_flags = SS_DISABLE;
 1010         td->td_sigstk.ss_size = 0;
 1011         td->td_sigstk.ss_sp = 0;
 1012         td->td_pflags &= ~TDP_ALTSTACK;
 1013         /*
 1014          * Reset no zombies if child dies flag as Solaris does.
 1015          */
 1016         ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
 1017         if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
 1018                 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
 1019         mtx_unlock(&ps->ps_mtx);
 1020 }
 1021 
 1022 /*
 1023  * kern_sigprocmask()
 1024  *
 1025  *      Manipulate signal mask.
 1026  */
 1027 int
 1028 kern_sigprocmask(struct thread *td, int how, sigset_t *set, sigset_t *oset,
 1029     int flags)
 1030 {
 1031         sigset_t new_block, oset1;
 1032         struct proc *p;
 1033         int error;
 1034 
 1035         p = td->td_proc;
 1036         if ((flags & SIGPROCMASK_PROC_LOCKED) != 0)
 1037                 PROC_LOCK_ASSERT(p, MA_OWNED);
 1038         else
 1039                 PROC_LOCK(p);
 1040         mtx_assert(&p->p_sigacts->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0
 1041             ? MA_OWNED : MA_NOTOWNED);
 1042         if (oset != NULL)
 1043                 *oset = td->td_sigmask;
 1044 
 1045         error = 0;
 1046         if (set != NULL) {
 1047                 switch (how) {
 1048                 case SIG_BLOCK:
 1049                         SIG_CANTMASK(*set);
 1050                         oset1 = td->td_sigmask;
 1051                         SIGSETOR(td->td_sigmask, *set);
 1052                         new_block = td->td_sigmask;
 1053                         SIGSETNAND(new_block, oset1);
 1054                         break;
 1055                 case SIG_UNBLOCK:
 1056                         SIGSETNAND(td->td_sigmask, *set);
 1057                         signotify(td);
 1058                         goto out;
 1059                 case SIG_SETMASK:
 1060                         SIG_CANTMASK(*set);
 1061                         oset1 = td->td_sigmask;
 1062                         if (flags & SIGPROCMASK_OLD)
 1063                                 SIGSETLO(td->td_sigmask, *set);
 1064                         else
 1065                                 td->td_sigmask = *set;
 1066                         new_block = td->td_sigmask;
 1067                         SIGSETNAND(new_block, oset1);
 1068                         signotify(td);
 1069                         break;
 1070                 default:
 1071                         error = EINVAL;
 1072                         goto out;
 1073                 }
 1074 
 1075                 /*
 1076                  * The new_block set contains signals that were not previously
 1077                  * blocked, but are blocked now.
 1078                  *
 1079                  * In case we block any signal that was not previously blocked
 1080                  * for td, and process has the signal pending, try to schedule
 1081                  * signal delivery to some thread that does not block the
 1082                  * signal, possibly waking it up.
 1083                  */
 1084                 if (p->p_numthreads != 1)
 1085                         reschedule_signals(p, new_block, flags);
 1086         }
 1087 
 1088 out:
 1089         if (!(flags & SIGPROCMASK_PROC_LOCKED))
 1090                 PROC_UNLOCK(p);
 1091         return (error);
 1092 }
 1093 
 1094 #ifndef _SYS_SYSPROTO_H_
 1095 struct sigprocmask_args {
 1096         int     how;
 1097         const sigset_t *set;
 1098         sigset_t *oset;
 1099 };
 1100 #endif
 1101 int
 1102 sys_sigprocmask(td, uap)
 1103         register struct thread *td;
 1104         struct sigprocmask_args *uap;
 1105 {
 1106         sigset_t set, oset;
 1107         sigset_t *setp, *osetp;
 1108         int error;
 1109 
 1110         setp = (uap->set != NULL) ? &set : NULL;
 1111         osetp = (uap->oset != NULL) ? &oset : NULL;
 1112         if (setp) {
 1113                 error = copyin(uap->set, setp, sizeof(set));
 1114                 if (error)
 1115                         return (error);
 1116         }
 1117         error = kern_sigprocmask(td, uap->how, setp, osetp, 0);
 1118         if (osetp && !error) {
 1119                 error = copyout(osetp, uap->oset, sizeof(oset));
 1120         }
 1121         return (error);
 1122 }
 1123 
 1124 #ifdef COMPAT_43        /* XXX - COMPAT_FBSD3 */
 1125 #ifndef _SYS_SYSPROTO_H_
 1126 struct osigprocmask_args {
 1127         int     how;
 1128         osigset_t mask;
 1129 };
 1130 #endif
 1131 int
 1132 osigprocmask(td, uap)
 1133         register struct thread *td;
 1134         struct osigprocmask_args *uap;
 1135 {
 1136         sigset_t set, oset;
 1137         int error;
 1138 
 1139         OSIG2SIG(uap->mask, set);
 1140         error = kern_sigprocmask(td, uap->how, &set, &oset, 1);
 1141         SIG2OSIG(oset, td->td_retval[0]);
 1142         return (error);
 1143 }
 1144 #endif /* COMPAT_43 */
 1145 
 1146 int
 1147 sys_sigwait(struct thread *td, struct sigwait_args *uap)
 1148 {
 1149         ksiginfo_t ksi;
 1150         sigset_t set;
 1151         int error;
 1152 
 1153         error = copyin(uap->set, &set, sizeof(set));
 1154         if (error) {
 1155                 td->td_retval[0] = error;
 1156                 return (0);
 1157         }
 1158 
 1159         error = kern_sigtimedwait(td, set, &ksi, NULL);
 1160         if (error) {
 1161                 if (error == EINTR && td->td_proc->p_osrel < P_OSREL_SIGWAIT)
 1162                         error = ERESTART;
 1163                 if (error == ERESTART)
 1164                         return (error);
 1165                 td->td_retval[0] = error;
 1166                 return (0);
 1167         }
 1168 
 1169         error = copyout(&ksi.ksi_signo, uap->sig, sizeof(ksi.ksi_signo));
 1170         td->td_retval[0] = error;
 1171         return (0);
 1172 }
 1173 
 1174 int
 1175 sys_sigtimedwait(struct thread *td, struct sigtimedwait_args *uap)
 1176 {
 1177         struct timespec ts;
 1178         struct timespec *timeout;
 1179         sigset_t set;
 1180         ksiginfo_t ksi;
 1181         int error;
 1182 
 1183         if (uap->timeout) {
 1184                 error = copyin(uap->timeout, &ts, sizeof(ts));
 1185                 if (error)
 1186                         return (error);
 1187 
 1188                 timeout = &ts;
 1189         } else
 1190                 timeout = NULL;
 1191 
 1192         error = copyin(uap->set, &set, sizeof(set));
 1193         if (error)
 1194                 return (error);
 1195 
 1196         error = kern_sigtimedwait(td, set, &ksi, timeout);
 1197         if (error)
 1198                 return (error);
 1199 
 1200         if (uap->info)
 1201                 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
 1202 
 1203         if (error == 0)
 1204                 td->td_retval[0] = ksi.ksi_signo;
 1205         return (error);
 1206 }
 1207 
 1208 int
 1209 sys_sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap)
 1210 {
 1211         ksiginfo_t ksi;
 1212         sigset_t set;
 1213         int error;
 1214 
 1215         error = copyin(uap->set, &set, sizeof(set));
 1216         if (error)
 1217                 return (error);
 1218 
 1219         error = kern_sigtimedwait(td, set, &ksi, NULL);
 1220         if (error)
 1221                 return (error);
 1222 
 1223         if (uap->info)
 1224                 error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t));
 1225 
 1226         if (error == 0)
 1227                 td->td_retval[0] = ksi.ksi_signo;
 1228         return (error);
 1229 }
 1230 
 1231 int
 1232 kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi,
 1233         struct timespec *timeout)
 1234 {
 1235         struct sigacts *ps;
 1236         sigset_t saved_mask, new_block;
 1237         struct proc *p;
 1238         int error, sig, timo, timevalid = 0;
 1239         struct timespec rts, ets, ts;
 1240         struct timeval tv;
 1241 
 1242         p = td->td_proc;
 1243         error = 0;
 1244         ets.tv_sec = 0;
 1245         ets.tv_nsec = 0;
 1246 
 1247         if (timeout != NULL) {
 1248                 if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) {
 1249                         timevalid = 1;
 1250                         getnanouptime(&rts);
 1251                         ets = rts;
 1252                         timespecadd(&ets, timeout);
 1253                 }
 1254         }
 1255         ksiginfo_init(ksi);
 1256         /* Some signals can not be waited for. */
 1257         SIG_CANTMASK(waitset);
 1258         ps = p->p_sigacts;
 1259         PROC_LOCK(p);
 1260         saved_mask = td->td_sigmask;
 1261         SIGSETNAND(td->td_sigmask, waitset);
 1262         for (;;) {
 1263                 mtx_lock(&ps->ps_mtx);
 1264                 sig = cursig(td);
 1265                 mtx_unlock(&ps->ps_mtx);
 1266                 if (sig != 0 && SIGISMEMBER(waitset, sig)) {
 1267                         if (sigqueue_get(&td->td_sigqueue, sig, ksi) != 0 ||
 1268                             sigqueue_get(&p->p_sigqueue, sig, ksi) != 0) {
 1269                                 error = 0;
 1270                                 break;
 1271                         }
 1272                 }
 1273 
 1274                 if (error != 0)
 1275                         break;
 1276 
 1277                 /*
 1278                  * POSIX says this must be checked after looking for pending
 1279                  * signals.
 1280                  */
 1281                 if (timeout != NULL) {
 1282                         if (!timevalid) {
 1283                                 error = EINVAL;
 1284                                 break;
 1285                         }
 1286                         getnanouptime(&rts);
 1287                         if (timespeccmp(&rts, &ets, >=)) {
 1288                                 error = EAGAIN;
 1289                                 break;
 1290                         }
 1291                         ts = ets;
 1292                         timespecsub(&ts, &rts);
 1293                         TIMESPEC_TO_TIMEVAL(&tv, &ts);
 1294                         timo = tvtohz(&tv);
 1295                 } else {
 1296                         timo = 0;
 1297                 }
 1298 
 1299                 error = msleep(ps, &p->p_mtx, PPAUSE|PCATCH, "sigwait", timo);
 1300 
 1301                 if (timeout != NULL) {
 1302                         if (error == ERESTART) {
 1303                                 /* Timeout can not be restarted. */
 1304                                 error = EINTR;
 1305                         } else if (error == EAGAIN) {
 1306                                 /* We will calculate timeout by ourself. */
 1307                                 error = 0;
 1308                         }
 1309                 }
 1310         }
 1311 
 1312         new_block = saved_mask;
 1313         SIGSETNAND(new_block, td->td_sigmask);
 1314         td->td_sigmask = saved_mask;
 1315         /*
 1316          * Fewer signals can be delivered to us, reschedule signal
 1317          * notification.
 1318          */
 1319         if (p->p_numthreads != 1)
 1320                 reschedule_signals(p, new_block, 0);
 1321 
 1322         if (error == 0) {
 1323                 SDT_PROBE2(proc, , , signal__clear, sig, ksi);
 1324 
 1325                 if (ksi->ksi_code == SI_TIMER)
 1326                         itimer_accept(p, ksi->ksi_timerid, ksi);
 1327 
 1328 #ifdef KTRACE
 1329                 if (KTRPOINT(td, KTR_PSIG)) {
 1330                         sig_t action;
 1331 
 1332                         mtx_lock(&ps->ps_mtx);
 1333                         action = ps->ps_sigact[_SIG_IDX(sig)];
 1334                         mtx_unlock(&ps->ps_mtx);
 1335                         ktrpsig(sig, action, &td->td_sigmask, ksi->ksi_code);
 1336                 }
 1337 #endif
 1338                 if (sig == SIGKILL)
 1339                         sigexit(td, sig);
 1340         }
 1341         PROC_UNLOCK(p);
 1342         return (error);
 1343 }
 1344 
 1345 #ifndef _SYS_SYSPROTO_H_
 1346 struct sigpending_args {
 1347         sigset_t        *set;
 1348 };
 1349 #endif
 1350 int
 1351 sys_sigpending(td, uap)
 1352         struct thread *td;
 1353         struct sigpending_args *uap;
 1354 {
 1355         struct proc *p = td->td_proc;
 1356         sigset_t pending;
 1357 
 1358         PROC_LOCK(p);
 1359         pending = p->p_sigqueue.sq_signals;
 1360         SIGSETOR(pending, td->td_sigqueue.sq_signals);
 1361         PROC_UNLOCK(p);
 1362         return (copyout(&pending, uap->set, sizeof(sigset_t)));
 1363 }
 1364 
 1365 #ifdef COMPAT_43        /* XXX - COMPAT_FBSD3 */
 1366 #ifndef _SYS_SYSPROTO_H_
 1367 struct osigpending_args {
 1368         int     dummy;
 1369 };
 1370 #endif
 1371 int
 1372 osigpending(td, uap)
 1373         struct thread *td;
 1374         struct osigpending_args *uap;
 1375 {
 1376         struct proc *p = td->td_proc;
 1377         sigset_t pending;
 1378 
 1379         PROC_LOCK(p);
 1380         pending = p->p_sigqueue.sq_signals;
 1381         SIGSETOR(pending, td->td_sigqueue.sq_signals);
 1382         PROC_UNLOCK(p);
 1383         SIG2OSIG(pending, td->td_retval[0]);
 1384         return (0);
 1385 }
 1386 #endif /* COMPAT_43 */
 1387 
 1388 #if defined(COMPAT_43)
 1389 /*
 1390  * Generalized interface signal handler, 4.3-compatible.
 1391  */
 1392 #ifndef _SYS_SYSPROTO_H_
 1393 struct osigvec_args {
 1394         int     signum;
 1395         struct  sigvec *nsv;
 1396         struct  sigvec *osv;
 1397 };
 1398 #endif
 1399 /* ARGSUSED */
 1400 int
 1401 osigvec(td, uap)
 1402         struct thread *td;
 1403         register struct osigvec_args *uap;
 1404 {
 1405         struct sigvec vec;
 1406         struct sigaction nsa, osa;
 1407         register struct sigaction *nsap, *osap;
 1408         int error;
 1409 
 1410         if (uap->signum <= 0 || uap->signum >= ONSIG)
 1411                 return (EINVAL);
 1412         nsap = (uap->nsv != NULL) ? &nsa : NULL;
 1413         osap = (uap->osv != NULL) ? &osa : NULL;
 1414         if (nsap) {
 1415                 error = copyin(uap->nsv, &vec, sizeof(vec));
 1416                 if (error)
 1417                         return (error);
 1418                 nsap->sa_handler = vec.sv_handler;
 1419                 OSIG2SIG(vec.sv_mask, nsap->sa_mask);
 1420                 nsap->sa_flags = vec.sv_flags;
 1421                 nsap->sa_flags ^= SA_RESTART;   /* opposite of SV_INTERRUPT */
 1422         }
 1423         error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET);
 1424         if (osap && !error) {
 1425                 vec.sv_handler = osap->sa_handler;
 1426                 SIG2OSIG(osap->sa_mask, vec.sv_mask);
 1427                 vec.sv_flags = osap->sa_flags;
 1428                 vec.sv_flags &= ~SA_NOCLDWAIT;
 1429                 vec.sv_flags ^= SA_RESTART;
 1430                 error = copyout(&vec, uap->osv, sizeof(vec));
 1431         }
 1432         return (error);
 1433 }
 1434 
 1435 #ifndef _SYS_SYSPROTO_H_
 1436 struct osigblock_args {
 1437         int     mask;
 1438 };
 1439 #endif
 1440 int
 1441 osigblock(td, uap)
 1442         register struct thread *td;
 1443         struct osigblock_args *uap;
 1444 {
 1445         sigset_t set, oset;
 1446 
 1447         OSIG2SIG(uap->mask, set);
 1448         kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0);
 1449         SIG2OSIG(oset, td->td_retval[0]);
 1450         return (0);
 1451 }
 1452 
 1453 #ifndef _SYS_SYSPROTO_H_
 1454 struct osigsetmask_args {
 1455         int     mask;
 1456 };
 1457 #endif
 1458 int
 1459 osigsetmask(td, uap)
 1460         struct thread *td;
 1461         struct osigsetmask_args *uap;
 1462 {
 1463         sigset_t set, oset;
 1464 
 1465         OSIG2SIG(uap->mask, set);
 1466         kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0);
 1467         SIG2OSIG(oset, td->td_retval[0]);
 1468         return (0);
 1469 }
 1470 #endif /* COMPAT_43 */
 1471 
 1472 /*
 1473  * Suspend calling thread until signal, providing mask to be set in the
 1474  * meantime.
 1475  */
 1476 #ifndef _SYS_SYSPROTO_H_
 1477 struct sigsuspend_args {
 1478         const sigset_t *sigmask;
 1479 };
 1480 #endif
 1481 /* ARGSUSED */
 1482 int
 1483 sys_sigsuspend(td, uap)
 1484         struct thread *td;
 1485         struct sigsuspend_args *uap;
 1486 {
 1487         sigset_t mask;
 1488         int error;
 1489 
 1490         error = copyin(uap->sigmask, &mask, sizeof(mask));
 1491         if (error)
 1492                 return (error);
 1493         return (kern_sigsuspend(td, mask));
 1494 }
 1495 
 1496 int
 1497 kern_sigsuspend(struct thread *td, sigset_t mask)
 1498 {
 1499         struct proc *p = td->td_proc;
 1500         int has_sig, sig;
 1501 
 1502         /*
 1503          * When returning from sigsuspend, we want
 1504          * the old mask to be restored after the
 1505          * signal handler has finished.  Thus, we
 1506          * save it here and mark the sigacts structure
 1507          * to indicate this.
 1508          */
 1509         PROC_LOCK(p);
 1510         kern_sigprocmask(td, SIG_SETMASK, &mask, &td->td_oldsigmask,
 1511             SIGPROCMASK_PROC_LOCKED);
 1512         td->td_pflags |= TDP_OLDMASK;
 1513 
 1514         /*
 1515          * Process signals now. Otherwise, we can get spurious wakeup
 1516          * due to signal entered process queue, but delivered to other
 1517          * thread. But sigsuspend should return only on signal
 1518          * delivery.
 1519          */
 1520         (p->p_sysent->sv_set_syscall_retval)(td, EINTR);
 1521         for (has_sig = 0; !has_sig;) {
 1522                 while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause",
 1523                         0) == 0)
 1524                         /* void */;
 1525                 thread_suspend_check(0);
 1526                 mtx_lock(&p->p_sigacts->ps_mtx);
 1527                 while ((sig = cursig(td)) != 0)
 1528                         has_sig += postsig(sig);
 1529                 mtx_unlock(&p->p_sigacts->ps_mtx);
 1530         }
 1531         PROC_UNLOCK(p);
 1532         td->td_errno = EINTR;
 1533         td->td_pflags |= TDP_NERRNO;
 1534         return (EJUSTRETURN);
 1535 }
 1536 
 1537 #ifdef COMPAT_43        /* XXX - COMPAT_FBSD3 */
 1538 /*
 1539  * Compatibility sigsuspend call for old binaries.  Note nonstandard calling
 1540  * convention: libc stub passes mask, not pointer, to save a copyin.
 1541  */
 1542 #ifndef _SYS_SYSPROTO_H_
 1543 struct osigsuspend_args {
 1544         osigset_t mask;
 1545 };
 1546 #endif
 1547 /* ARGSUSED */
 1548 int
 1549 osigsuspend(td, uap)
 1550         struct thread *td;
 1551         struct osigsuspend_args *uap;
 1552 {
 1553         sigset_t mask;
 1554 
 1555         OSIG2SIG(uap->mask, mask);
 1556         return (kern_sigsuspend(td, mask));
 1557 }
 1558 #endif /* COMPAT_43 */
 1559 
 1560 #if defined(COMPAT_43)
 1561 #ifndef _SYS_SYSPROTO_H_
 1562 struct osigstack_args {
 1563         struct  sigstack *nss;
 1564         struct  sigstack *oss;
 1565 };
 1566 #endif
 1567 /* ARGSUSED */
 1568 int
 1569 osigstack(td, uap)
 1570         struct thread *td;
 1571         register struct osigstack_args *uap;
 1572 {
 1573         struct sigstack nss, oss;
 1574         int error = 0;
 1575 
 1576         if (uap->nss != NULL) {
 1577                 error = copyin(uap->nss, &nss, sizeof(nss));
 1578                 if (error)
 1579                         return (error);
 1580         }
 1581         oss.ss_sp = td->td_sigstk.ss_sp;
 1582         oss.ss_onstack = sigonstack(cpu_getstack(td));
 1583         if (uap->nss != NULL) {
 1584                 td->td_sigstk.ss_sp = nss.ss_sp;
 1585                 td->td_sigstk.ss_size = 0;
 1586                 td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK;
 1587                 td->td_pflags |= TDP_ALTSTACK;
 1588         }
 1589         if (uap->oss != NULL)
 1590                 error = copyout(&oss, uap->oss, sizeof(oss));
 1591 
 1592         return (error);
 1593 }
 1594 #endif /* COMPAT_43 */
 1595 
 1596 #ifndef _SYS_SYSPROTO_H_
 1597 struct sigaltstack_args {
 1598         stack_t *ss;
 1599         stack_t *oss;
 1600 };
 1601 #endif
 1602 /* ARGSUSED */
 1603 int
 1604 sys_sigaltstack(td, uap)
 1605         struct thread *td;
 1606         register struct sigaltstack_args *uap;
 1607 {
 1608         stack_t ss, oss;
 1609         int error;
 1610 
 1611         if (uap->ss != NULL) {
 1612                 error = copyin(uap->ss, &ss, sizeof(ss));
 1613                 if (error)
 1614                         return (error);
 1615         }
 1616         error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL,
 1617             (uap->oss != NULL) ? &oss : NULL);
 1618         if (error)
 1619                 return (error);
 1620         if (uap->oss != NULL)
 1621                 error = copyout(&oss, uap->oss, sizeof(stack_t));
 1622         return (error);
 1623 }
 1624 
 1625 int
 1626 kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss)
 1627 {
 1628         struct proc *p = td->td_proc;
 1629         int oonstack;
 1630 
 1631         oonstack = sigonstack(cpu_getstack(td));
 1632 
 1633         if (oss != NULL) {
 1634                 *oss = td->td_sigstk;
 1635                 oss->ss_flags = (td->td_pflags & TDP_ALTSTACK)
 1636                     ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
 1637         }
 1638 
 1639         if (ss != NULL) {
 1640                 if (oonstack)
 1641                         return (EPERM);
 1642                 if ((ss->ss_flags & ~SS_DISABLE) != 0)
 1643                         return (EINVAL);
 1644                 if (!(ss->ss_flags & SS_DISABLE)) {
 1645                         if (ss->ss_size < p->p_sysent->sv_minsigstksz)
 1646                                 return (ENOMEM);
 1647 
 1648                         td->td_sigstk = *ss;
 1649                         td->td_pflags |= TDP_ALTSTACK;
 1650                 } else {
 1651                         td->td_pflags &= ~TDP_ALTSTACK;
 1652                 }
 1653         }
 1654         return (0);
 1655 }
 1656 
 1657 /*
 1658  * Common code for kill process group/broadcast kill.
 1659  * cp is calling process.
 1660  */
 1661 static int
 1662 killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi)
 1663 {
 1664         struct proc *p;
 1665         struct pgrp *pgrp;
 1666         int err;
 1667         int ret;
 1668 
 1669         ret = ESRCH;
 1670         if (all) {
 1671                 /*
 1672                  * broadcast
 1673                  */
 1674                 sx_slock(&allproc_lock);
 1675                 FOREACH_PROC_IN_SYSTEM(p) {
 1676                         PROC_LOCK(p);
 1677                         if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
 1678                             p == td->td_proc || p->p_state == PRS_NEW) {
 1679                                 PROC_UNLOCK(p);
 1680                                 continue;
 1681                         }
 1682                         err = p_cansignal(td, p, sig);
 1683                         if (err == 0) {
 1684                                 if (sig)
 1685                                         pksignal(p, sig, ksi);
 1686                                 ret = err;
 1687                         }
 1688                         else if (ret == ESRCH)
 1689                                 ret = err;
 1690                         PROC_UNLOCK(p);
 1691                 }
 1692                 sx_sunlock(&allproc_lock);
 1693         } else {
 1694                 sx_slock(&proctree_lock);
 1695                 if (pgid == 0) {
 1696                         /*
 1697                          * zero pgid means send to my process group.
 1698                          */
 1699                         pgrp = td->td_proc->p_pgrp;
 1700                         PGRP_LOCK(pgrp);
 1701                 } else {
 1702                         pgrp = pgfind(pgid);
 1703                         if (pgrp == NULL) {
 1704                                 sx_sunlock(&proctree_lock);
 1705                                 return (ESRCH);
 1706                         }
 1707                 }
 1708                 sx_sunlock(&proctree_lock);
 1709                 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
 1710                         PROC_LOCK(p);
 1711                         if (p->p_pid <= 1 || p->p_flag & P_SYSTEM ||
 1712                             p->p_state == PRS_NEW) {
 1713                                 PROC_UNLOCK(p);
 1714                                 continue;
 1715                         }
 1716                         err = p_cansignal(td, p, sig);
 1717                         if (err == 0) {
 1718                                 if (sig)
 1719                                         pksignal(p, sig, ksi);
 1720                                 ret = err;
 1721                         }
 1722                         else if (ret == ESRCH)
 1723                                 ret = err;
 1724                         PROC_UNLOCK(p);
 1725                 }
 1726                 PGRP_UNLOCK(pgrp);
 1727         }
 1728         return (ret);
 1729 }
 1730 
 1731 #ifndef _SYS_SYSPROTO_H_
 1732 struct kill_args {
 1733         int     pid;
 1734         int     signum;
 1735 };
 1736 #endif
 1737 /* ARGSUSED */
 1738 int
 1739 sys_kill(struct thread *td, struct kill_args *uap)
 1740 {
 1741         ksiginfo_t ksi;
 1742         struct proc *p;
 1743         int error;
 1744 
 1745         /*
 1746          * A process in capability mode can send signals only to himself.
 1747          * The main rationale behind this is that abort(3) is implemented as
 1748          * kill(getpid(), SIGABRT).
 1749          */
 1750         if (IN_CAPABILITY_MODE(td) && uap->pid != td->td_proc->p_pid)
 1751                 return (ECAPMODE);
 1752 
 1753         AUDIT_ARG_SIGNUM(uap->signum);
 1754         AUDIT_ARG_PID(uap->pid);
 1755         if ((u_int)uap->signum > _SIG_MAXSIG)
 1756                 return (EINVAL);
 1757 
 1758         ksiginfo_init(&ksi);
 1759         ksi.ksi_signo = uap->signum;
 1760         ksi.ksi_code = SI_USER;
 1761         ksi.ksi_pid = td->td_proc->p_pid;
 1762         ksi.ksi_uid = td->td_ucred->cr_ruid;
 1763 
 1764         if (uap->pid > 0) {
 1765                 /* kill single process */
 1766                 if ((p = pfind(uap->pid)) == NULL) {
 1767                         if ((p = zpfind(uap->pid)) == NULL)
 1768                                 return (ESRCH);
 1769                 }
 1770                 AUDIT_ARG_PROCESS(p);
 1771                 error = p_cansignal(td, p, uap->signum);
 1772                 if (error == 0 && uap->signum)
 1773                         pksignal(p, uap->signum, &ksi);
 1774                 PROC_UNLOCK(p);
 1775                 return (error);
 1776         }
 1777         switch (uap->pid) {
 1778         case -1:                /* broadcast signal */
 1779                 return (killpg1(td, uap->signum, 0, 1, &ksi));
 1780         case 0:                 /* signal own process group */
 1781                 return (killpg1(td, uap->signum, 0, 0, &ksi));
 1782         default:                /* negative explicit process group */
 1783                 return (killpg1(td, uap->signum, -uap->pid, 0, &ksi));
 1784         }
 1785         /* NOTREACHED */
 1786 }
 1787 
 1788 int
 1789 sys_pdkill(td, uap)
 1790         struct thread *td;
 1791         struct pdkill_args *uap;
 1792 {
 1793 #ifdef PROCDESC
 1794         struct proc *p;
 1795         cap_rights_t rights;
 1796         int error;
 1797 
 1798         AUDIT_ARG_SIGNUM(uap->signum);
 1799         AUDIT_ARG_FD(uap->fd);
 1800         if ((u_int)uap->signum > _SIG_MAXSIG)
 1801                 return (EINVAL);
 1802 
 1803         error = procdesc_find(td, uap->fd,
 1804             cap_rights_init(&rights, CAP_PDKILL), &p);
 1805         if (error)
 1806                 return (error);
 1807         AUDIT_ARG_PROCESS(p);
 1808         error = p_cansignal(td, p, uap->signum);
 1809         if (error == 0 && uap->signum)
 1810                 kern_psignal(p, uap->signum);
 1811         PROC_UNLOCK(p);
 1812         return (error);
 1813 #else
 1814         return (ENOSYS);
 1815 #endif
 1816 }
 1817 
 1818 #if defined(COMPAT_43)
 1819 #ifndef _SYS_SYSPROTO_H_
 1820 struct okillpg_args {
 1821         int     pgid;
 1822         int     signum;
 1823 };
 1824 #endif
 1825 /* ARGSUSED */
 1826 int
 1827 okillpg(struct thread *td, struct okillpg_args *uap)
 1828 {
 1829         ksiginfo_t ksi;
 1830 
 1831         AUDIT_ARG_SIGNUM(uap->signum);
 1832         AUDIT_ARG_PID(uap->pgid);
 1833         if ((u_int)uap->signum > _SIG_MAXSIG)
 1834                 return (EINVAL);
 1835 
 1836         ksiginfo_init(&ksi);
 1837         ksi.ksi_signo = uap->signum;
 1838         ksi.ksi_code = SI_USER;
 1839         ksi.ksi_pid = td->td_proc->p_pid;
 1840         ksi.ksi_uid = td->td_ucred->cr_ruid;
 1841         return (killpg1(td, uap->signum, uap->pgid, 0, &ksi));
 1842 }
 1843 #endif /* COMPAT_43 */
 1844 
 1845 #ifndef _SYS_SYSPROTO_H_
 1846 struct sigqueue_args {
 1847         pid_t pid;
 1848         int signum;
 1849         /* union sigval */ void *value;
 1850 };
 1851 #endif
 1852 int
 1853 sys_sigqueue(struct thread *td, struct sigqueue_args *uap)
 1854 {
 1855         union sigval sv;
 1856 
 1857         sv.sival_ptr = uap->value;
 1858 
 1859         return (kern_sigqueue(td, uap->pid, uap->signum, &sv));
 1860 }
 1861 
 1862 int
 1863 kern_sigqueue(struct thread *td, pid_t pid, int signum, union sigval *value)
 1864 {
 1865         ksiginfo_t ksi;
 1866         struct proc *p;
 1867         int error;
 1868 
 1869         if ((u_int)signum > _SIG_MAXSIG)
 1870                 return (EINVAL);
 1871 
 1872         /*
 1873          * Specification says sigqueue can only send signal to
 1874          * single process.
 1875          */
 1876         if (pid <= 0)
 1877                 return (EINVAL);
 1878 
 1879         if ((p = pfind(pid)) == NULL) {
 1880                 if ((p = zpfind(pid)) == NULL)
 1881                         return (ESRCH);
 1882         }
 1883         error = p_cansignal(td, p, signum);
 1884         if (error == 0 && signum != 0) {
 1885                 ksiginfo_init(&ksi);
 1886                 ksi.ksi_flags = KSI_SIGQ;
 1887                 ksi.ksi_signo = signum;
 1888                 ksi.ksi_code = SI_QUEUE;
 1889                 ksi.ksi_pid = td->td_proc->p_pid;
 1890                 ksi.ksi_uid = td->td_ucred->cr_ruid;
 1891                 ksi.ksi_value = *value;
 1892                 error = pksignal(p, ksi.ksi_signo, &ksi);
 1893         }
 1894         PROC_UNLOCK(p);
 1895         return (error);
 1896 }
 1897 
 1898 /*
 1899  * Send a signal to a process group.
 1900  */
 1901 void
 1902 gsignal(int pgid, int sig, ksiginfo_t *ksi)
 1903 {
 1904         struct pgrp *pgrp;
 1905 
 1906         if (pgid != 0) {
 1907                 sx_slock(&proctree_lock);
 1908                 pgrp = pgfind(pgid);
 1909                 sx_sunlock(&proctree_lock);
 1910                 if (pgrp != NULL) {
 1911                         pgsignal(pgrp, sig, 0, ksi);
 1912                         PGRP_UNLOCK(pgrp);
 1913                 }
 1914         }
 1915 }
 1916 
 1917 /*
 1918  * Send a signal to a process group.  If checktty is 1,
 1919  * limit to members which have a controlling terminal.
 1920  */
 1921 void
 1922 pgsignal(struct pgrp *pgrp, int sig, int checkctty, ksiginfo_t *ksi)
 1923 {
 1924         struct proc *p;
 1925 
 1926         if (pgrp) {
 1927                 PGRP_LOCK_ASSERT(pgrp, MA_OWNED);
 1928                 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
 1929                         PROC_LOCK(p);
 1930                         if (p->p_state == PRS_NORMAL &&
 1931                             (checkctty == 0 || p->p_flag & P_CONTROLT))
 1932                                 pksignal(p, sig, ksi);
 1933                         PROC_UNLOCK(p);
 1934                 }
 1935         }
 1936 }
 1937 
 1938 
 1939 /*
 1940  * Recalculate the signal mask and reset the signal disposition after
 1941  * usermode frame for delivery is formed.  Should be called after
 1942  * mach-specific routine, because sysent->sv_sendsig() needs correct
 1943  * ps_siginfo and signal mask.
 1944  */
 1945 static void
 1946 postsig_done(int sig, struct thread *td, struct sigacts *ps)
 1947 {
 1948         sigset_t mask;
 1949 
 1950         mtx_assert(&ps->ps_mtx, MA_OWNED);
 1951         td->td_ru.ru_nsignals++;
 1952         mask = ps->ps_catchmask[_SIG_IDX(sig)];
 1953         if (!SIGISMEMBER(ps->ps_signodefer, sig))
 1954                 SIGADDSET(mask, sig);
 1955         kern_sigprocmask(td, SIG_BLOCK, &mask, NULL,
 1956             SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED);
 1957         if (SIGISMEMBER(ps->ps_sigreset, sig))
 1958                 sigdflt(ps, sig);
 1959 }
 1960 
 1961 
 1962 /*
 1963  * Send a signal caused by a trap to the current thread.  If it will be
 1964  * caught immediately, deliver it with correct code.  Otherwise, post it
 1965  * normally.
 1966  */
 1967 void
 1968 trapsignal(struct thread *td, ksiginfo_t *ksi)
 1969 {
 1970         struct sigacts *ps;
 1971         struct proc *p;
 1972         int sig;
 1973         int code;
 1974 
 1975         p = td->td_proc;
 1976         sig = ksi->ksi_signo;
 1977         code = ksi->ksi_code;
 1978         KASSERT(_SIG_VALID(sig), ("invalid signal"));
 1979 
 1980         PROC_LOCK(p);
 1981         ps = p->p_sigacts;
 1982         mtx_lock(&ps->ps_mtx);
 1983         if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) &&
 1984             !SIGISMEMBER(td->td_sigmask, sig)) {
 1985 #ifdef KTRACE
 1986                 if (KTRPOINT(curthread, KTR_PSIG))
 1987                         ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)],
 1988                             &td->td_sigmask, code);
 1989 #endif
 1990                 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)],
 1991                                 ksi, &td->td_sigmask);
 1992                 postsig_done(sig, td, ps);
 1993                 mtx_unlock(&ps->ps_mtx);
 1994         } else {
 1995                 /*
 1996                  * Avoid a possible infinite loop if the thread
 1997                  * masking the signal or process is ignoring the
 1998                  * signal.
 1999                  */
 2000                 if (kern_forcesigexit &&
 2001                     (SIGISMEMBER(td->td_sigmask, sig) ||
 2002                      ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN)) {
 2003                         SIGDELSET(td->td_sigmask, sig);
 2004                         SIGDELSET(ps->ps_sigcatch, sig);
 2005                         SIGDELSET(ps->ps_sigignore, sig);
 2006                         ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
 2007                 }
 2008                 mtx_unlock(&ps->ps_mtx);
 2009                 p->p_code = code;       /* XXX for core dump/debugger */
 2010                 p->p_sig = sig;         /* XXX to verify code */
 2011                 tdsendsignal(p, td, sig, ksi);
 2012         }
 2013         PROC_UNLOCK(p);
 2014 }
 2015 
 2016 static struct thread *
 2017 sigtd(struct proc *p, int sig, int prop)
 2018 {
 2019         struct thread *td, *signal_td;
 2020 
 2021         PROC_LOCK_ASSERT(p, MA_OWNED);
 2022 
 2023         /*
 2024          * Check if current thread can handle the signal without
 2025          * switching context to another thread.
 2026          */
 2027         if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig))
 2028                 return (curthread);
 2029         signal_td = NULL;
 2030         FOREACH_THREAD_IN_PROC(p, td) {
 2031                 if (!SIGISMEMBER(td->td_sigmask, sig)) {
 2032                         signal_td = td;
 2033                         break;
 2034                 }
 2035         }
 2036         if (signal_td == NULL)
 2037                 signal_td = FIRST_THREAD_IN_PROC(p);
 2038         return (signal_td);
 2039 }
 2040 
 2041 /*
 2042  * Send the signal to the process.  If the signal has an action, the action
 2043  * is usually performed by the target process rather than the caller; we add
 2044  * the signal to the set of pending signals for the process.
 2045  *
 2046  * Exceptions:
 2047  *   o When a stop signal is sent to a sleeping process that takes the
 2048  *     default action, the process is stopped without awakening it.
 2049  *   o SIGCONT restarts stopped processes (or puts them back to sleep)
 2050  *     regardless of the signal action (eg, blocked or ignored).
 2051  *
 2052  * Other ignored signals are discarded immediately.
 2053  *
 2054  * NB: This function may be entered from the debugger via the "kill" DDB
 2055  * command.  There is little that can be done to mitigate the possibly messy
 2056  * side effects of this unwise possibility.
 2057  */
 2058 void
 2059 kern_psignal(struct proc *p, int sig)
 2060 {
 2061         ksiginfo_t ksi;
 2062 
 2063         ksiginfo_init(&ksi);
 2064         ksi.ksi_signo = sig;
 2065         ksi.ksi_code = SI_KERNEL;
 2066         (void) tdsendsignal(p, NULL, sig, &ksi);
 2067 }
 2068 
 2069 int
 2070 pksignal(struct proc *p, int sig, ksiginfo_t *ksi)
 2071 {
 2072 
 2073         return (tdsendsignal(p, NULL, sig, ksi));
 2074 }
 2075 
 2076 /* Utility function for finding a thread to send signal event to. */
 2077 int
 2078 sigev_findtd(struct proc *p ,struct sigevent *sigev, struct thread **ttd)
 2079 {
 2080         struct thread *td;
 2081 
 2082         if (sigev->sigev_notify == SIGEV_THREAD_ID) {
 2083                 td = tdfind(sigev->sigev_notify_thread_id, p->p_pid);
 2084                 if (td == NULL)
 2085                         return (ESRCH);
 2086                 *ttd = td;
 2087         } else {
 2088                 *ttd = NULL;
 2089                 PROC_LOCK(p);
 2090         }
 2091         return (0);
 2092 }
 2093 
 2094 void
 2095 tdsignal(struct thread *td, int sig)
 2096 {
 2097         ksiginfo_t ksi;
 2098 
 2099         ksiginfo_init(&ksi);
 2100         ksi.ksi_signo = sig;
 2101         ksi.ksi_code = SI_KERNEL;
 2102         (void) tdsendsignal(td->td_proc, td, sig, &ksi);
 2103 }
 2104 
 2105 void
 2106 tdksignal(struct thread *td, int sig, ksiginfo_t *ksi)
 2107 {
 2108 
 2109         (void) tdsendsignal(td->td_proc, td, sig, ksi);
 2110 }
 2111 
 2112 int
 2113 tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
 2114 {
 2115         sig_t action;
 2116         sigqueue_t *sigqueue;
 2117         int prop;
 2118         struct sigacts *ps;
 2119         int intrval;
 2120         int ret = 0;
 2121         int wakeup_swapper;
 2122 
 2123         MPASS(td == NULL || p == td->td_proc);
 2124         PROC_LOCK_ASSERT(p, MA_OWNED);
 2125 
 2126         if (!_SIG_VALID(sig))
 2127                 panic("%s(): invalid signal %d", __func__, sig);
 2128 
 2129         KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", __func__));
 2130 
 2131         /*
 2132          * IEEE Std 1003.1-2001: return success when killing a zombie.
 2133          */
 2134         if (p->p_state == PRS_ZOMBIE) {
 2135                 if (ksi && (ksi->ksi_flags & KSI_INS))
 2136                         ksiginfo_tryfree(ksi);
 2137                 return (ret);
 2138         }
 2139 
 2140         ps = p->p_sigacts;
 2141         KNOTE_LOCKED(&p->p_klist, NOTE_SIGNAL | sig);
 2142         prop = sigprop(sig);
 2143 
 2144         if (td == NULL) {
 2145                 td = sigtd(p, sig, prop);
 2146                 sigqueue = &p->p_sigqueue;
 2147         } else
 2148                 sigqueue = &td->td_sigqueue;
 2149 
 2150         SDT_PROBE3(proc, , , signal__send, td, p, sig);
 2151 
 2152         /*
 2153          * If the signal is being ignored,
 2154          * then we forget about it immediately.
 2155          * (Note: we don't set SIGCONT in ps_sigignore,
 2156          * and if it is set to SIG_IGN,
 2157          * action will be SIG_DFL here.)
 2158          */
 2159         mtx_lock(&ps->ps_mtx);
 2160         if (SIGISMEMBER(ps->ps_sigignore, sig)) {
 2161                 SDT_PROBE3(proc, , , signal__discard, td, p, sig);
 2162 
 2163                 mtx_unlock(&ps->ps_mtx);
 2164                 if (ksi && (ksi->ksi_flags & KSI_INS))
 2165                         ksiginfo_tryfree(ksi);
 2166                 return (ret);
 2167         }
 2168         if (SIGISMEMBER(td->td_sigmask, sig))
 2169                 action = SIG_HOLD;
 2170         else if (SIGISMEMBER(ps->ps_sigcatch, sig))
 2171                 action = SIG_CATCH;
 2172         else
 2173                 action = SIG_DFL;
 2174         if (SIGISMEMBER(ps->ps_sigintr, sig))
 2175                 intrval = EINTR;
 2176         else
 2177                 intrval = ERESTART;
 2178         mtx_unlock(&ps->ps_mtx);
 2179 
 2180         if (prop & SA_CONT)
 2181                 sigqueue_delete_stopmask_proc(p);
 2182         else if (prop & SA_STOP) {
 2183                 /*
 2184                  * If sending a tty stop signal to a member of an orphaned
 2185                  * process group, discard the signal here if the action
 2186                  * is default; don't stop the process below if sleeping,
 2187                  * and don't clear any pending SIGCONT.
 2188                  */
 2189                 if ((prop & SA_TTYSTOP) &&
 2190                     (p->p_pgrp->pg_jobc == 0) &&
 2191                     (action == SIG_DFL)) {
 2192                         if (ksi && (ksi->ksi_flags & KSI_INS))
 2193                                 ksiginfo_tryfree(ksi);
 2194                         return (ret);
 2195                 }
 2196                 sigqueue_delete_proc(p, SIGCONT);
 2197                 if (p->p_flag & P_CONTINUED) {
 2198                         p->p_flag &= ~P_CONTINUED;
 2199                         PROC_LOCK(p->p_pptr);
 2200                         sigqueue_take(p->p_ksi);
 2201                         PROC_UNLOCK(p->p_pptr);
 2202                 }
 2203         }
 2204 
 2205         ret = sigqueue_add(sigqueue, sig, ksi);
 2206         if (ret != 0)
 2207                 return (ret);
 2208         signotify(td);
 2209         /*
 2210          * Defer further processing for signals which are held,
 2211          * except that stopped processes must be continued by SIGCONT.
 2212          */
 2213         if (action == SIG_HOLD &&
 2214             !((prop & SA_CONT) && (p->p_flag & P_STOPPED_SIG)))
 2215                 return (ret);
 2216 
 2217         /* SIGKILL: Remove procfs STOPEVENTs. */
 2218         if (sig == SIGKILL) {
 2219                 /* from procfs_ioctl.c: PIOCBIC */
 2220                 p->p_stops = 0;
 2221                 /* from procfs_ioctl.c: PIOCCONT */
 2222                 p->p_step = 0;
 2223                 wakeup(&p->p_step);
 2224         }
 2225         /*
 2226          * Some signals have a process-wide effect and a per-thread
 2227          * component.  Most processing occurs when the process next
 2228          * tries to cross the user boundary, however there are some
 2229          * times when processing needs to be done immediately, such as
 2230          * waking up threads so that they can cross the user boundary.
 2231          * We try to do the per-process part here.
 2232          */
 2233         if (P_SHOULDSTOP(p)) {
 2234                 KASSERT(!(p->p_flag & P_WEXIT),
 2235                     ("signal to stopped but exiting process"));
 2236                 if (sig == SIGKILL) {
 2237                         /*
 2238                          * If traced process is already stopped,
 2239                          * then no further action is necessary.
 2240                          */
 2241                         if (p->p_flag & P_TRACED)
 2242                                 goto out;
 2243                         /*
 2244                          * SIGKILL sets process running.
 2245                          * It will die elsewhere.
 2246                          * All threads must be restarted.
 2247                          */
 2248                         p->p_flag &= ~P_STOPPED_SIG;
 2249                         goto runfast;
 2250                 }
 2251 
 2252                 if (prop & SA_CONT) {
 2253                         /*
 2254                          * If traced process is already stopped,
 2255                          * then no further action is necessary.
 2256                          */
 2257                         if (p->p_flag & P_TRACED)
 2258                                 goto out;
 2259                         /*
 2260                          * If SIGCONT is default (or ignored), we continue the
 2261                          * process but don't leave the signal in sigqueue as
 2262                          * it has no further action.  If SIGCONT is held, we
 2263                          * continue the process and leave the signal in
 2264                          * sigqueue.  If the process catches SIGCONT, let it
 2265                          * handle the signal itself.  If it isn't waiting on
 2266                          * an event, it goes back to run state.
 2267                          * Otherwise, process goes back to sleep state.
 2268                          */
 2269                         p->p_flag &= ~P_STOPPED_SIG;
 2270                         PROC_SLOCK(p);
 2271                         if (p->p_numthreads == p->p_suspcount) {
 2272                                 PROC_SUNLOCK(p);
 2273                                 p->p_flag |= P_CONTINUED;
 2274                                 p->p_xstat = SIGCONT;
 2275                                 PROC_LOCK(p->p_pptr);
 2276                                 childproc_continued(p);
 2277                                 PROC_UNLOCK(p->p_pptr);
 2278                                 PROC_SLOCK(p);
 2279                         }
 2280                         if (action == SIG_DFL) {
 2281                                 thread_unsuspend(p);
 2282                                 PROC_SUNLOCK(p);
 2283                                 sigqueue_delete(sigqueue, sig);
 2284                                 goto out;
 2285                         }
 2286                         if (action == SIG_CATCH) {
 2287                                 /*
 2288                                  * The process wants to catch it so it needs
 2289                                  * to run at least one thread, but which one?
 2290                                  */
 2291                                 PROC_SUNLOCK(p);
 2292                                 goto runfast;
 2293                         }
 2294                         /*
 2295                          * The signal is not ignored or caught.
 2296                          */
 2297                         thread_unsuspend(p);
 2298                         PROC_SUNLOCK(p);
 2299                         goto out;
 2300                 }
 2301 
 2302                 if (prop & SA_STOP) {
 2303                         /*
 2304                          * If traced process is already stopped,
 2305                          * then no further action is necessary.
 2306                          */
 2307                         if (p->p_flag & P_TRACED)
 2308                                 goto out;
 2309                         /*
 2310                          * Already stopped, don't need to stop again
 2311                          * (If we did the shell could get confused).
 2312                          * Just make sure the signal STOP bit set.
 2313                          */
 2314                         p->p_flag |= P_STOPPED_SIG;
 2315                         sigqueue_delete(sigqueue, sig);
 2316                         goto out;
 2317                 }
 2318 
 2319                 /*
 2320                  * All other kinds of signals:
 2321                  * If a thread is sleeping interruptibly, simulate a
 2322                  * wakeup so that when it is continued it will be made
 2323                  * runnable and can look at the signal.  However, don't make
 2324                  * the PROCESS runnable, leave it stopped.
 2325                  * It may run a bit until it hits a thread_suspend_check().
 2326                  */
 2327                 wakeup_swapper = 0;
 2328                 PROC_SLOCK(p);
 2329                 thread_lock(td);
 2330                 if (TD_ON_SLEEPQ(td) && (td->td_flags & TDF_SINTR))
 2331                         wakeup_swapper = sleepq_abort(td, intrval);
 2332                 thread_unlock(td);
 2333                 PROC_SUNLOCK(p);
 2334                 if (wakeup_swapper)
 2335                         kick_proc0();
 2336                 goto out;
 2337                 /*
 2338                  * Mutexes are short lived. Threads waiting on them will
 2339                  * hit thread_suspend_check() soon.
 2340                  */
 2341         } else if (p->p_state == PRS_NORMAL) {
 2342                 if (p->p_flag & P_TRACED || action == SIG_CATCH) {
 2343                         tdsigwakeup(td, sig, action, intrval);
 2344                         goto out;
 2345                 }
 2346 
 2347                 MPASS(action == SIG_DFL);
 2348 
 2349                 if (prop & SA_STOP) {
 2350                         if (p->p_flag & (P_PPWAIT|P_WEXIT))
 2351                                 goto out;
 2352                         p->p_flag |= P_STOPPED_SIG;
 2353                         p->p_xstat = sig;
 2354                         PROC_SLOCK(p);
 2355                         sig_suspend_threads(td, p, 1);
 2356                         if (p->p_numthreads == p->p_suspcount) {
 2357                                 /*
 2358                                  * only thread sending signal to another
 2359                                  * process can reach here, if thread is sending
 2360                                  * signal to its process, because thread does
 2361                                  * not suspend itself here, p_numthreads
 2362                                  * should never be equal to p_suspcount.
 2363                                  */
 2364                                 thread_stopped(p);
 2365                                 PROC_SUNLOCK(p);
 2366                                 sigqueue_delete_proc(p, p->p_xstat);
 2367                         } else
 2368                                 PROC_SUNLOCK(p);
 2369                         goto out;
 2370                 }
 2371         } else {
 2372                 /* Not in "NORMAL" state. discard the signal. */
 2373                 sigqueue_delete(sigqueue, sig);
 2374                 goto out;
 2375         }
 2376 
 2377         /*
 2378          * The process is not stopped so we need to apply the signal to all the
 2379          * running threads.
 2380          */
 2381 runfast:
 2382         tdsigwakeup(td, sig, action, intrval);
 2383         PROC_SLOCK(p);
 2384         thread_unsuspend(p);
 2385         PROC_SUNLOCK(p);
 2386 out:
 2387         /* If we jump here, proc slock should not be owned. */
 2388         PROC_SLOCK_ASSERT(p, MA_NOTOWNED);
 2389         return (ret);
 2390 }
 2391 
 2392 /*
 2393  * The force of a signal has been directed against a single
 2394  * thread.  We need to see what we can do about knocking it
 2395  * out of any sleep it may be in etc.
 2396  */
 2397 static void
 2398 tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval)
 2399 {
 2400         struct proc *p = td->td_proc;
 2401         register int prop;
 2402         int wakeup_swapper;
 2403 
 2404         wakeup_swapper = 0;
 2405         PROC_LOCK_ASSERT(p, MA_OWNED);
 2406         prop = sigprop(sig);
 2407 
 2408         PROC_SLOCK(p);
 2409         thread_lock(td);
 2410         /*
 2411          * Bring the priority of a thread up if we want it to get
 2412          * killed in this lifetime.  Be careful to avoid bumping the
 2413          * priority of the idle thread, since we still allow to signal
 2414          * kernel processes.
 2415          */
 2416         if (action == SIG_DFL && (prop & SA_KILL) != 0 &&
 2417             td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
 2418                 sched_prio(td, PUSER);
 2419         if (TD_ON_SLEEPQ(td)) {
 2420                 /*
 2421                  * If thread is sleeping uninterruptibly
 2422                  * we can't interrupt the sleep... the signal will
 2423                  * be noticed when the process returns through
 2424                  * trap() or syscall().
 2425                  */
 2426                 if ((td->td_flags & TDF_SINTR) == 0)
 2427                         goto out;
 2428                 /*
 2429                  * If SIGCONT is default (or ignored) and process is
 2430                  * asleep, we are finished; the process should not
 2431                  * be awakened.
 2432                  */
 2433                 if ((prop & SA_CONT) && action == SIG_DFL) {
 2434                         thread_unlock(td);
 2435                         PROC_SUNLOCK(p);
 2436                         sigqueue_delete(&p->p_sigqueue, sig);
 2437                         /*
 2438                          * It may be on either list in this state.
 2439                          * Remove from both for now.
 2440                          */
 2441                         sigqueue_delete(&td->td_sigqueue, sig);
 2442                         return;
 2443                 }
 2444 
 2445                 /*
 2446                  * Don't awaken a sleeping thread for SIGSTOP if the
 2447                  * STOP signal is deferred.
 2448                  */
 2449                 if ((prop & SA_STOP) && (td->td_flags & TDF_SBDRY))
 2450                         goto out;
 2451 
 2452                 /*
 2453                  * Give low priority threads a better chance to run.
 2454                  */
 2455                 if (td->td_priority > PUSER && !TD_IS_IDLETHREAD(td))
 2456                         sched_prio(td, PUSER);
 2457 
 2458                 wakeup_swapper = sleepq_abort(td, intrval);
 2459         } else {
 2460                 /*
 2461                  * Other states do nothing with the signal immediately,
 2462                  * other than kicking ourselves if we are running.
 2463                  * It will either never be noticed, or noticed very soon.
 2464                  */
 2465 #ifdef SMP
 2466                 if (TD_IS_RUNNING(td) && td != curthread)
 2467                         forward_signal(td);
 2468 #endif
 2469         }
 2470 out:
 2471         PROC_SUNLOCK(p);
 2472         thread_unlock(td);
 2473         if (wakeup_swapper)
 2474                 kick_proc0();
 2475 }
 2476 
 2477 static void
 2478 sig_suspend_threads(struct thread *td, struct proc *p, int sending)
 2479 {
 2480         struct thread *td2;
 2481 
 2482         PROC_LOCK_ASSERT(p, MA_OWNED);
 2483         PROC_SLOCK_ASSERT(p, MA_OWNED);
 2484 
 2485         FOREACH_THREAD_IN_PROC(p, td2) {
 2486                 thread_lock(td2);
 2487                 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
 2488                 if ((TD_IS_SLEEPING(td2) || TD_IS_SWAPPED(td2)) &&
 2489                     (td2->td_flags & TDF_SINTR)) {
 2490                         if (td2->td_flags & TDF_SBDRY) {
 2491                                 /*
 2492                                  * Once a thread is asleep with
 2493                                  * TDF_SBDRY set, it should never
 2494                                  * become suspended due to this check.
 2495                                  */
 2496                                 KASSERT(!TD_IS_SUSPENDED(td2),
 2497                                     ("thread with deferred stops suspended"));
 2498                         } else if (!TD_IS_SUSPENDED(td2)) {
 2499                                 thread_suspend_one(td2);
 2500                         }
 2501                 } else if (!TD_IS_SUSPENDED(td2)) {
 2502                         if (sending || td != td2)
 2503                                 td2->td_flags |= TDF_ASTPENDING;
 2504 #ifdef SMP
 2505                         if (TD_IS_RUNNING(td2) && td2 != td)
 2506                                 forward_signal(td2);
 2507 #endif
 2508                 }
 2509                 thread_unlock(td2);
 2510         }
 2511 }
 2512 
 2513 /*
 2514  * Stop the process for an event deemed interesting to the debugger. If si is
 2515  * non-NULL, this is a signal exchange; the new signal requested by the
 2516  * debugger will be returned for handling. If si is NULL, this is some other
 2517  * type of interesting event. The debugger may request a signal be delivered in
 2518  * that case as well, however it will be deferred until it can be handled.
 2519  */
 2520 int
 2521 ptracestop(struct thread *td, int sig, ksiginfo_t *si)
 2522 {
 2523         struct proc *p = td->td_proc;
 2524         struct thread *td2;
 2525         ksiginfo_t ksi;
 2526         int prop;
 2527 
 2528         PROC_LOCK_ASSERT(p, MA_OWNED);
 2529         KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process"));
 2530         WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
 2531             &p->p_mtx.lock_object, "Stopping for traced signal");
 2532 
 2533         td->td_xsig = sig;
 2534 
 2535         if (si == NULL || (si->ksi_flags & KSI_PTRACE) == 0) {
 2536                 td->td_dbgflags |= TDB_XSIG;
 2537                 CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d",
 2538                     td->td_tid, p->p_pid, td->td_dbgflags, sig);
 2539                 PROC_SLOCK(p);
 2540                 while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) {
 2541                         if (P_KILLED(p)) {
 2542                                 /*
 2543                                  * Ensure that, if we've been PT_KILLed, the
 2544                                  * exit status reflects that. Another thread
 2545                                  * may also be in ptracestop(), having just
 2546                                  * received the SIGKILL, but this thread was
 2547                                  * unsuspended first.
 2548                                  */
 2549                                 td->td_dbgflags &= ~TDB_XSIG;
 2550                                 td->td_xsig = SIGKILL;
 2551                                 p->p_ptevents = 0;
 2552                                 break;
 2553                         }
 2554                         if (p->p_flag & P_SINGLE_EXIT &&
 2555                             !(td->td_dbgflags & TDB_EXIT)) {
 2556                                 /*
 2557                                  * Ignore ptrace stops except for thread exit
 2558                                  * events when the process exits.
 2559                                  */
 2560                                 td->td_dbgflags &= ~TDB_XSIG;
 2561                                 PROC_SUNLOCK(p);
 2562                                 return (0);
 2563                         }
 2564 
 2565                         /*
 2566                          * Make wait(2) work.  Ensure that right after the
 2567                          * attach, the thread which was decided to become the
 2568                          * leader of attach gets reported to the waiter.
 2569                          * Otherwise, just avoid overwriting another thread's
 2570                          * assignment to p_xthread.  If another thread has
 2571                          * already set p_xthread, the current thread will get
 2572                          * a chance to report itself upon the next iteration.
 2573                          */
 2574                         if ((td->td_dbgflags & TDB_FSTP) != 0 ||
 2575                             ((p->p_flag2 & P2_PTRACE_FSTP) == 0 &&
 2576                             p->p_xthread == NULL)) {
 2577                                 p->p_xstat = sig;
 2578                                 p->p_xthread = td;
 2579                                 td->td_dbgflags &= ~TDB_FSTP;
 2580                                 p->p_flag2 &= ~P2_PTRACE_FSTP;
 2581                                 p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE;
 2582                                 sig_suspend_threads(td, p, 0);
 2583                         }
 2584                         if ((td->td_dbgflags & TDB_STOPATFORK) != 0) {
 2585                                 td->td_dbgflags &= ~TDB_STOPATFORK;
 2586                                 cv_broadcast(&p->p_dbgwait);
 2587                         }
 2588 stopme:
 2589                         thread_suspend_switch(td, p);
 2590                         if (p->p_xthread == td)
 2591                                 p->p_xthread = NULL;
 2592                         if (!(p->p_flag & P_TRACED))
 2593                                 break;
 2594                         if (td->td_dbgflags & TDB_SUSPEND) {
 2595                                 if (p->p_flag & P_SINGLE_EXIT)
 2596                                         break;
 2597                                 goto stopme;
 2598                         }
 2599                 }
 2600                 PROC_SUNLOCK(p);
 2601         }
 2602 
 2603         if (si != NULL && sig == td->td_xsig) {
 2604                 /* Parent wants us to take the original signal unchanged. */
 2605                 si->ksi_flags |= KSI_HEAD;
 2606                 if (sigqueue_add(&td->td_sigqueue, sig, si) != 0)
 2607                         si->ksi_signo = 0;
 2608         } else if (td->td_xsig != 0) {
 2609                 /*
 2610                  * If parent wants us to take a new signal, then it will leave
 2611                  * it in td->td_xsig; otherwise we just look for signals again.
 2612                  */
 2613                 ksiginfo_init(&ksi);
 2614                 ksi.ksi_signo = td->td_xsig;
 2615                 ksi.ksi_flags |= KSI_PTRACE;
 2616                 prop = sigprop(td->td_xsig);
 2617                 td2 = sigtd(p, td->td_xsig, prop);
 2618                 tdsendsignal(p, td2, td->td_xsig, &ksi);
 2619                 if (td != td2)
 2620                         return (0);
 2621         }
 2622 
 2623         return (td->td_xsig);
 2624 }
 2625 
 2626 static void
 2627 reschedule_signals(struct proc *p, sigset_t block, int flags)
 2628 {
 2629         struct sigacts *ps;
 2630         struct thread *td;
 2631         int sig;
 2632 
 2633         PROC_LOCK_ASSERT(p, MA_OWNED);
 2634         ps = p->p_sigacts;
 2635         mtx_assert(&ps->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0 ?
 2636             MA_OWNED : MA_NOTOWNED);
 2637         if (SIGISEMPTY(p->p_siglist))
 2638                 return;
 2639         SIGSETAND(block, p->p_siglist);
 2640         while ((sig = sig_ffs(&block)) != 0) {
 2641                 SIGDELSET(block, sig);
 2642                 td = sigtd(p, sig, 0);
 2643                 signotify(td);
 2644                 if (!(flags & SIGPROCMASK_PS_LOCKED))
 2645                         mtx_lock(&ps->ps_mtx);
 2646                 if (p->p_flag & P_TRACED ||
 2647                     (SIGISMEMBER(ps->ps_sigcatch, sig) &&
 2648                     !SIGISMEMBER(td->td_sigmask, sig)))
 2649                         tdsigwakeup(td, sig, SIG_CATCH,
 2650                             (SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR :
 2651                              ERESTART));
 2652                 if (!(flags & SIGPROCMASK_PS_LOCKED))
 2653                         mtx_unlock(&ps->ps_mtx);
 2654         }
 2655 }
 2656 
 2657 void
 2658 tdsigcleanup(struct thread *td)
 2659 {
 2660         struct proc *p;
 2661         sigset_t unblocked;
 2662 
 2663         p = td->td_proc;
 2664         PROC_LOCK_ASSERT(p, MA_OWNED);
 2665 
 2666         sigqueue_flush(&td->td_sigqueue);
 2667         if (p->p_numthreads == 1)
 2668                 return;
 2669 
 2670         /*
 2671          * Since we cannot handle signals, notify signal post code
 2672          * about this by filling the sigmask.
 2673          *
 2674          * Also, if needed, wake up thread(s) that do not block the
 2675          * same signals as the exiting thread, since the thread might
 2676          * have been selected for delivery and woken up.
 2677          */
 2678         SIGFILLSET(unblocked);
 2679         SIGSETNAND(unblocked, td->td_sigmask);
 2680         SIGFILLSET(td->td_sigmask);
 2681         reschedule_signals(p, unblocked, 0);
 2682 
 2683 }
 2684 
 2685 /*
 2686  * Defer the delivery of SIGSTOP for the current thread.  Returns true
 2687  * if stops were deferred and false if they were already deferred.
 2688  */
 2689 int
 2690 sigdeferstop(void)
 2691 {
 2692         struct thread *td;
 2693 
 2694         td = curthread;
 2695         if (td->td_flags & TDF_SBDRY)
 2696                 return (0);
 2697         thread_lock(td);
 2698         td->td_flags |= TDF_SBDRY;
 2699         thread_unlock(td);
 2700         return (1);
 2701 }
 2702 
 2703 /*
 2704  * Permit the delivery of SIGSTOP for the current thread.  This does
 2705  * not immediately suspend if a stop was posted.  Instead, the thread
 2706  * will suspend either via ast() or a subsequent interruptible sleep.
 2707  */
 2708 int
 2709 sigallowstop(void)
 2710 {
 2711         struct thread *td;
 2712         int prev;
 2713 
 2714         td = curthread;
 2715         thread_lock(td);
 2716         prev = (td->td_flags & TDF_SBDRY) != 0;
 2717         td->td_flags &= ~TDF_SBDRY;
 2718         thread_unlock(td);
 2719         return (prev);
 2720 }
 2721 
 2722 /*
 2723  * If the current process has received a signal (should be caught or cause
 2724  * termination, should interrupt current syscall), return the signal number.
 2725  * Stop signals with default action are processed immediately, then cleared;
 2726  * they aren't returned.  This is checked after each entry to the system for
 2727  * a syscall or trap (though this can usually be done without calling issignal
 2728  * by checking the pending signal masks in cursig.) The normal call
 2729  * sequence is
 2730  *
 2731  *      while (sig = cursig(curthread))
 2732  *              postsig(sig);
 2733  */
 2734 static int
 2735 issignal(struct thread *td)
 2736 {
 2737         struct proc *p;
 2738         struct sigacts *ps;
 2739         struct sigqueue *queue;
 2740         sigset_t sigpending;
 2741         int sig, prop;
 2742 
 2743         p = td->td_proc;
 2744         ps = p->p_sigacts;
 2745         mtx_assert(&ps->ps_mtx, MA_OWNED);
 2746         PROC_LOCK_ASSERT(p, MA_OWNED);
 2747         for (;;) {
 2748                 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
 2749 
 2750                 sigpending = td->td_sigqueue.sq_signals;
 2751                 SIGSETOR(sigpending, p->p_sigqueue.sq_signals);
 2752                 SIGSETNAND(sigpending, td->td_sigmask);
 2753 
 2754                 if (p->p_flag & P_PPWAIT || td->td_flags & TDF_SBDRY)
 2755                         SIG_STOPSIGMASK(sigpending);
 2756                 if (SIGISEMPTY(sigpending))     /* no signal to send */
 2757                         return (0);
 2758                 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED &&
 2759                     (p->p_flag2 & P2_PTRACE_FSTP) != 0 &&
 2760                     SIGISMEMBER(sigpending, SIGSTOP)) {
 2761                         /*
 2762                          * If debugger just attached, always consume
 2763                          * SIGSTOP from ptrace(PT_ATTACH) first, to
 2764                          * execute the debugger attach ritual in
 2765                          * order.
 2766                          */
 2767                         sig = SIGSTOP;
 2768                         td->td_dbgflags |= TDB_FSTP;
 2769                 } else {
 2770                         sig = sig_ffs(&sigpending);
 2771                 }
 2772 
 2773                 if (p->p_stops & S_SIG) {
 2774                         mtx_unlock(&ps->ps_mtx);
 2775                         stopevent(p, S_SIG, sig);
 2776                         mtx_lock(&ps->ps_mtx);
 2777                 }
 2778 
 2779                 /*
 2780                  * We should see pending but ignored signals
 2781                  * only if P_TRACED was on when they were posted.
 2782                  */
 2783                 if (SIGISMEMBER(ps->ps_sigignore, sig) && (traced == 0)) {
 2784                         sigqueue_delete(&td->td_sigqueue, sig);
 2785                         sigqueue_delete(&p->p_sigqueue, sig);
 2786                         continue;
 2787                 }
 2788                 if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) {
 2789                         /*
 2790                          * If traced, always stop.
 2791                          * Remove old signal from queue before the stop.
 2792                          * XXX shrug off debugger, it causes siginfo to
 2793                          * be thrown away.
 2794                          */
 2795                         queue = &td->td_sigqueue;
 2796                         td->td_dbgksi.ksi_signo = 0;
 2797                         if (sigqueue_get(queue, sig, &td->td_dbgksi) == 0) {
 2798                                 queue = &p->p_sigqueue;
 2799                                 sigqueue_get(queue, sig, &td->td_dbgksi);
 2800                         }
 2801 
 2802                         mtx_unlock(&ps->ps_mtx);
 2803                         sig = ptracestop(td, sig, &td->td_dbgksi);
 2804                         mtx_lock(&ps->ps_mtx);
 2805 
 2806                         /* 
 2807                          * Keep looking if the debugger discarded the signal
 2808                          * or replaced it with a masked signal.
 2809                          *
 2810                          * If the traced bit got turned off, go back up
 2811                          * to the top to rescan signals.  This ensures
 2812                          * that p_sig* and p_sigact are consistent.
 2813                          */
 2814                         if (sig == 0 || (p->p_flag & P_TRACED) == 0)
 2815                                 continue;
 2816                 }
 2817 
 2818                 prop = sigprop(sig);
 2819 
 2820                 /*
 2821                  * Decide whether the signal should be returned.
 2822                  * Return the signal's number, or fall through
 2823                  * to clear it from the pending mask.
 2824                  */
 2825                 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
 2826 
 2827                 case (intptr_t)SIG_DFL:
 2828                         /*
 2829                          * Don't take default actions on system processes.
 2830                          */
 2831                         if (p->p_pid <= 1) {
 2832 #ifdef DIAGNOSTIC
 2833                                 /*
 2834                                  * Are you sure you want to ignore SIGSEGV
 2835                                  * in init? XXX
 2836                                  */
 2837                                 printf("Process (pid %lu) got signal %d\n",
 2838                                         (u_long)p->p_pid, sig);
 2839 #endif
 2840                                 break;          /* == ignore */
 2841                         }
 2842                         /*
 2843                          * If there is a pending stop signal to process with
 2844                          * default action, stop here, then clear the signal.
 2845                          * Traced or exiting processes should ignore stops.
 2846                          * Additionally, a member of an orphaned process group
 2847                          * should ignore tty stops.
 2848                          */
 2849                         if (prop & SA_STOP) {
 2850                                 if (p->p_flag &
 2851                                     (P_TRACED | P_WEXIT | P_SINGLE_EXIT) ||
 2852                                     (p->p_pgrp->pg_jobc == 0 &&
 2853                                      prop & SA_TTYSTOP))
 2854                                         break;  /* == ignore */
 2855                                 mtx_unlock(&ps->ps_mtx);
 2856                                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
 2857                                     &p->p_mtx.lock_object, "Catching SIGSTOP");
 2858                                 sigqueue_delete(&td->td_sigqueue, sig);
 2859                                 sigqueue_delete(&p->p_sigqueue, sig);
 2860                                 p->p_flag |= P_STOPPED_SIG;
 2861                                 p->p_xstat = sig;
 2862                                 PROC_SLOCK(p);
 2863                                 sig_suspend_threads(td, p, 0);
 2864                                 thread_suspend_switch(td, p);
 2865                                 PROC_SUNLOCK(p);
 2866                                 mtx_lock(&ps->ps_mtx);
 2867                                 goto next;
 2868                         } else if (prop & SA_IGNORE) {
 2869                                 /*
 2870                                  * Except for SIGCONT, shouldn't get here.
 2871                                  * Default action is to ignore; drop it.
 2872                                  */
 2873                                 break;          /* == ignore */
 2874                         } else
 2875                                 return (sig);
 2876                         /*NOTREACHED*/
 2877 
 2878                 case (intptr_t)SIG_IGN:
 2879                         /*
 2880                          * Masking above should prevent us ever trying
 2881                          * to take action on an ignored signal other
 2882                          * than SIGCONT, unless process is traced.
 2883                          */
 2884                         if ((prop & SA_CONT) == 0 &&
 2885                             (p->p_flag & P_TRACED) == 0)
 2886                                 printf("issignal\n");
 2887                         break;          /* == ignore */
 2888 
 2889                 default:
 2890                         /*
 2891                          * This signal has an action, let
 2892                          * postsig() process it.
 2893                          */
 2894                         return (sig);
 2895                 }
 2896                 sigqueue_delete(&td->td_sigqueue, sig); /* take the signal! */
 2897                 sigqueue_delete(&p->p_sigqueue, sig);
 2898 next:;
 2899         }
 2900         /* NOTREACHED */
 2901 }
 2902 
 2903 void
 2904 thread_stopped(struct proc *p)
 2905 {
 2906         int n;
 2907 
 2908         PROC_LOCK_ASSERT(p, MA_OWNED);
 2909         PROC_SLOCK_ASSERT(p, MA_OWNED);
 2910         n = p->p_suspcount;
 2911         if (p == curproc)
 2912                 n++;
 2913         if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) {
 2914                 PROC_SUNLOCK(p);
 2915                 p->p_flag &= ~P_WAITED;
 2916                 PROC_LOCK(p->p_pptr);
 2917                 childproc_stopped(p, (p->p_flag & P_TRACED) ?
 2918                         CLD_TRAPPED : CLD_STOPPED);
 2919                 PROC_UNLOCK(p->p_pptr);
 2920                 PROC_SLOCK(p);
 2921         }
 2922 }
 2923 
 2924 /*
 2925  * Take the action for the specified signal
 2926  * from the current set of pending signals.
 2927  */
 2928 int
 2929 postsig(sig)
 2930         register int sig;
 2931 {
 2932         struct thread *td = curthread;
 2933         register struct proc *p = td->td_proc;
 2934         struct sigacts *ps;
 2935         sig_t action;
 2936         ksiginfo_t ksi;
 2937         sigset_t returnmask;
 2938 
 2939         KASSERT(sig != 0, ("postsig"));
 2940 
 2941         PROC_LOCK_ASSERT(p, MA_OWNED);
 2942         ps = p->p_sigacts;
 2943         mtx_assert(&ps->ps_mtx, MA_OWNED);
 2944         ksiginfo_init(&ksi);
 2945         if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 &&
 2946             sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0)
 2947                 return (0);
 2948         ksi.ksi_signo = sig;
 2949         if (ksi.ksi_code == SI_TIMER)
 2950                 itimer_accept(p, ksi.ksi_timerid, &ksi);
 2951         action = ps->ps_sigact[_SIG_IDX(sig)];
 2952 #ifdef KTRACE
 2953         if (KTRPOINT(td, KTR_PSIG))
 2954                 ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ?
 2955                     &td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code);
 2956 #endif
 2957         if (p->p_stops & S_SIG) {
 2958                 mtx_unlock(&ps->ps_mtx);
 2959                 stopevent(p, S_SIG, sig);
 2960                 mtx_lock(&ps->ps_mtx);
 2961         }
 2962 
 2963         if (action == SIG_DFL) {
 2964                 /*
 2965                  * Default action, where the default is to kill
 2966                  * the process.  (Other cases were ignored above.)
 2967                  */
 2968                 mtx_unlock(&ps->ps_mtx);
 2969                 sigexit(td, sig);
 2970                 /* NOTREACHED */
 2971         } else {
 2972                 /*
 2973                  * If we get here, the signal must be caught.
 2974                  */
 2975                 KASSERT(action != SIG_IGN && !SIGISMEMBER(td->td_sigmask, sig),
 2976                     ("postsig action"));
 2977                 /*
 2978                  * Set the new mask value and also defer further
 2979                  * occurrences of this signal.
 2980                  *
 2981                  * Special case: user has done a sigsuspend.  Here the
 2982                  * current mask is not of interest, but rather the
 2983                  * mask from before the sigsuspend is what we want
 2984                  * restored after the signal processing is completed.
 2985                  */
 2986                 if (td->td_pflags & TDP_OLDMASK) {
 2987                         returnmask = td->td_oldsigmask;
 2988                         td->td_pflags &= ~TDP_OLDMASK;
 2989                 } else
 2990                         returnmask = td->td_sigmask;
 2991 
 2992                 if (p->p_sig == sig) {
 2993                         p->p_code = 0;
 2994                         p->p_sig = 0;
 2995                 }
 2996                 (*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask);
 2997                 postsig_done(sig, td, ps);
 2998         }
 2999         return (1);
 3000 }
 3001 
 3002 /*
 3003  * Kill the current process for stated reason.
 3004  */
 3005 void
 3006 killproc(p, why)
 3007         struct proc *p;
 3008         char *why;
 3009 {
 3010 
 3011         PROC_LOCK_ASSERT(p, MA_OWNED);
 3012         CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid,
 3013             p->p_comm);
 3014         log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid,
 3015             p->p_comm, p->p_ucred ? p->p_ucred->cr_uid : -1, why);
 3016         p->p_flag |= P_WKILLED;
 3017         kern_psignal(p, SIGKILL);
 3018 }
 3019 
 3020 /*
 3021  * Force the current process to exit with the specified signal, dumping core
 3022  * if appropriate.  We bypass the normal tests for masked and caught signals,
 3023  * allowing unrecoverable failures to terminate the process without changing
 3024  * signal state.  Mark the accounting record with the signal termination.
 3025  * If dumping core, save the signal number for the debugger.  Calls exit and
 3026  * does not return.
 3027  */
 3028 void
 3029 sigexit(td, sig)
 3030         struct thread *td;
 3031         int sig;
 3032 {
 3033         struct proc *p = td->td_proc;
 3034 
 3035         PROC_LOCK_ASSERT(p, MA_OWNED);
 3036         p->p_acflag |= AXSIG;
 3037         /*
 3038          * We must be single-threading to generate a core dump.  This
 3039          * ensures that the registers in the core file are up-to-date.
 3040          * Also, the ELF dump handler assumes that the thread list doesn't
 3041          * change out from under it.
 3042          *
 3043          * XXX If another thread attempts to single-thread before us
 3044          *     (e.g. via fork()), we won't get a dump at all.
 3045          */
 3046         if ((sigprop(sig) & SA_CORE) && thread_single(p, SINGLE_NO_EXIT) == 0) {
 3047                 p->p_sig = sig;
 3048                 /*
 3049                  * Log signals which would cause core dumps
 3050                  * (Log as LOG_INFO to appease those who don't want
 3051                  * these messages.)
 3052                  * XXX : Todo, as well as euid, write out ruid too
 3053                  * Note that coredump() drops proc lock.
 3054                  */
 3055                 if (coredump(td) == 0)
 3056                         sig |= WCOREFLAG;
 3057                 if (kern_logsigexit)
 3058                         log(LOG_INFO,
 3059                             "pid %d (%s), uid %d: exited on signal %d%s\n",
 3060                             p->p_pid, p->p_comm,
 3061                             td->td_ucred ? td->td_ucred->cr_uid : -1,
 3062                             sig &~ WCOREFLAG,
 3063                             sig & WCOREFLAG ? " (core dumped)" : "");
 3064         } else
 3065                 PROC_UNLOCK(p);
 3066         exit1(td, W_EXITCODE(0, sig));
 3067         /* NOTREACHED */
 3068 }
 3069 
 3070 /*
 3071  * Send queued SIGCHLD to parent when child process's state
 3072  * is changed.
 3073  */
 3074 static void
 3075 sigparent(struct proc *p, int reason, int status)
 3076 {
 3077         PROC_LOCK_ASSERT(p, MA_OWNED);
 3078         PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
 3079 
 3080         if (p->p_ksi != NULL) {
 3081                 p->p_ksi->ksi_signo  = SIGCHLD;
 3082                 p->p_ksi->ksi_code   = reason;
 3083                 p->p_ksi->ksi_status = status;
 3084                 p->p_ksi->ksi_pid    = p->p_pid;
 3085                 p->p_ksi->ksi_uid    = p->p_ucred->cr_ruid;
 3086                 if (KSI_ONQ(p->p_ksi))
 3087                         return;
 3088         }
 3089         pksignal(p->p_pptr, SIGCHLD, p->p_ksi);
 3090 }
 3091 
 3092 static void
 3093 childproc_jobstate(struct proc *p, int reason, int sig)
 3094 {
 3095         struct sigacts *ps;
 3096 
 3097         PROC_LOCK_ASSERT(p, MA_OWNED);
 3098         PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED);
 3099 
 3100         /*
 3101          * Wake up parent sleeping in kern_wait(), also send
 3102          * SIGCHLD to parent, but SIGCHLD does not guarantee
 3103          * that parent will awake, because parent may masked
 3104          * the signal.
 3105          */
 3106         p->p_pptr->p_flag |= P_STATCHILD;
 3107         wakeup(p->p_pptr);
 3108 
 3109         ps = p->p_pptr->p_sigacts;
 3110         mtx_lock(&ps->ps_mtx);
 3111         if ((ps->ps_flag & PS_NOCLDSTOP) == 0) {
 3112                 mtx_unlock(&ps->ps_mtx);
 3113                 sigparent(p, reason, sig);
 3114         } else
 3115                 mtx_unlock(&ps->ps_mtx);
 3116 }
 3117 
 3118 void
 3119 childproc_stopped(struct proc *p, int reason)
 3120 {
 3121         /* p_xstat is a plain signal number, not a full wait() status here. */
 3122         childproc_jobstate(p, reason, p->p_xstat);
 3123 }
 3124 
 3125 void
 3126 childproc_continued(struct proc *p)
 3127 {
 3128         childproc_jobstate(p, CLD_CONTINUED, SIGCONT);
 3129 }
 3130 
 3131 void
 3132 childproc_exited(struct proc *p)
 3133 {
 3134         int reason;
 3135         int xstat = p->p_xstat; /* convert to int */
 3136         int status;
 3137 
 3138         if (WCOREDUMP(xstat))
 3139                 reason = CLD_DUMPED, status = WTERMSIG(xstat);
 3140         else if (WIFSIGNALED(xstat))
 3141                 reason = CLD_KILLED, status = WTERMSIG(xstat);
 3142         else
 3143                 reason = CLD_EXITED, status = WEXITSTATUS(xstat);
 3144         /*
 3145          * XXX avoid calling wakeup(p->p_pptr), the work is
 3146          * done in exit1().
 3147          */
 3148         sigparent(p, reason, status);
 3149 }
 3150 
 3151 /*
 3152  * We only have 1 character for the core count in the format
 3153  * string, so the range will be 0-9
 3154  */
 3155 #define MAX_NUM_CORES 10
 3156 static int num_cores = 5;
 3157 
 3158 static int
 3159 sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS)
 3160 {
 3161         int error;
 3162         int new_val;
 3163 
 3164         new_val = num_cores;
 3165         error = sysctl_handle_int(oidp, &new_val, 0, req);
 3166         if (error != 0 || req->newptr == NULL)
 3167                 return (error);
 3168         if (new_val > MAX_NUM_CORES)
 3169                 new_val = MAX_NUM_CORES;
 3170         if (new_val < 0)
 3171                 new_val = 0;
 3172         num_cores = new_val;
 3173         return (0);
 3174 }
 3175 SYSCTL_PROC(_debug, OID_AUTO, ncores, CTLTYPE_INT|CTLFLAG_RW,
 3176             0, sizeof(int), sysctl_debug_num_cores_check, "I", "");
 3177 
 3178 #if defined(COMPRESS_USER_CORES)
 3179 int compress_user_cores = 1;
 3180 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores, CTLFLAG_RW,
 3181     &compress_user_cores, 0, "Compression of user corefiles");
 3182 
 3183 int compress_user_cores_gzlevel = -1; /* default level */
 3184 SYSCTL_INT(_kern, OID_AUTO, compress_user_cores_gzlevel, CTLFLAG_RW,
 3185     &compress_user_cores_gzlevel, -1, "Corefile gzip compression level");
 3186 
 3187 #define GZ_SUFFIX       ".gz"
 3188 #define GZ_SUFFIX_LEN   3
 3189 #endif
 3190 
 3191 static char corefilename[MAXPATHLEN] = {"%N.core"};
 3192 TUNABLE_STR("kern.corefile", corefilename, sizeof(corefilename));
 3193 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
 3194     sizeof(corefilename), "Process corefile name format string");
 3195 
 3196 /*
 3197  * corefile_open(comm, uid, pid, td, compress, vpp, namep)
 3198  * Expand the name described in corefilename, using name, uid, and pid
 3199  * and open/create core file.
 3200  * corefilename is a printf-like string, with three format specifiers:
 3201  *      %N      name of process ("name")
 3202  *      %P      process id (pid)
 3203  *      %U      user id (uid)
 3204  * For example, "%N.core" is the default; they can be disabled completely
 3205  * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
 3206  * This is controlled by the sysctl variable kern.corefile (see above).
 3207  */
 3208 static int
 3209 corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td,
 3210     int compress, struct vnode **vpp, char **namep)
 3211 {
 3212         struct nameidata nd;
 3213         struct sbuf sb;
 3214         const char *format;
 3215         char *hostname, *name;
 3216         int indexpos, i, error, cmode, flags, oflags;
 3217 
 3218         hostname = NULL;
 3219         format = corefilename;
 3220         name = malloc(MAXPATHLEN, M_TEMP, M_WAITOK | M_ZERO);
 3221         indexpos = -1;
 3222         (void)sbuf_new(&sb, name, MAXPATHLEN, SBUF_FIXEDLEN);
 3223         for (i = 0; format[i] != '\0'; i++) {
 3224                 switch (format[i]) {
 3225                 case '%':       /* Format character */
 3226                         i++;
 3227                         switch (format[i]) {
 3228                         case '%':
 3229                                 sbuf_putc(&sb, '%');
 3230                                 break;
 3231                         case 'H':       /* hostname */
 3232                                 if (hostname == NULL) {
 3233                                         hostname = malloc(MAXHOSTNAMELEN,
 3234                                             M_TEMP, M_WAITOK);
 3235                                 }
 3236                                 getcredhostname(td->td_ucred, hostname,
 3237                                     MAXHOSTNAMELEN);
 3238                                 sbuf_printf(&sb, "%s", hostname);
 3239                                 break;
 3240                         case 'I':       /* autoincrementing index */
 3241                                 sbuf_printf(&sb, "");
 3242                                 indexpos = sbuf_len(&sb) - 1;
 3243                                 break;
 3244                         case 'N':       /* process name */
 3245                                 sbuf_printf(&sb, "%s", comm);
 3246                                 break;
 3247                         case 'P':       /* process id */
 3248                                 sbuf_printf(&sb, "%u", pid);
 3249                                 break;
 3250                         case 'U':       /* user id */
 3251                                 sbuf_printf(&sb, "%u", uid);
 3252                                 break;
 3253                         default:
 3254                                 log(LOG_ERR,
 3255                                     "Unknown format character %c in "
 3256                                     "corename `%s'\n", format[i], format);
 3257                                 break;
 3258                         }
 3259                         break;
 3260                 default:
 3261                         sbuf_putc(&sb, format[i]);
 3262                         break;
 3263                 }
 3264         }
 3265         free(hostname, M_TEMP);
 3266 #ifdef COMPRESS_USER_CORES
 3267         if (compress)
 3268                 sbuf_printf(&sb, GZ_SUFFIX);
 3269 #endif
 3270         if (sbuf_error(&sb) != 0) {
 3271                 log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too "
 3272                     "long\n", (long)pid, comm, (u_long)uid);
 3273                 sbuf_delete(&sb);
 3274                 free(name, M_TEMP);
 3275                 return (ENOMEM);
 3276         }
 3277         sbuf_finish(&sb);
 3278         sbuf_delete(&sb);
 3279 
 3280         cmode = S_IRUSR | S_IWUSR;
 3281         oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE |
 3282             (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0);
 3283 
 3284         /*
 3285          * If the core format has a %I in it, then we need to check
 3286          * for existing corefiles before returning a name.
 3287          * To do this we iterate over 0..num_cores to find a
 3288          * non-existing core file name to use.
 3289          */
 3290         if (indexpos != -1) {
 3291                 for (i = 0; i < num_cores; i++) {
 3292                         flags = O_CREAT | O_EXCL | FWRITE | O_NOFOLLOW;
 3293                         name[indexpos] = '' + i;
 3294                         NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
 3295                         error = vn_open_cred(&nd, &flags, cmode, oflags,
 3296                             td->td_ucred, NULL);
 3297                         if (error) {
 3298                                 if (error == EEXIST)
 3299                                         continue;
 3300                                 log(LOG_ERR,
 3301                                     "pid %d (%s), uid (%u):  Path `%s' failed "
 3302                                     "on initial open test, error = %d\n",
 3303                                     pid, comm, uid, name, error);
 3304                         }
 3305                         goto out;
 3306                 }
 3307         }
 3308 
 3309         flags = O_CREAT | FWRITE | O_NOFOLLOW;
 3310         NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
 3311         error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, NULL);
 3312 out:
 3313         if (error) {
 3314 #ifdef AUDIT
 3315                 audit_proc_coredump(td, name, error);
 3316 #endif
 3317                 free(name, M_TEMP);
 3318                 return (error);
 3319         }
 3320         NDFREE(&nd, NDF_ONLY_PNBUF);
 3321         *vpp = nd.ni_vp;
 3322         *namep = name;
 3323         return (0);
 3324 }
 3325 
 3326 static int
 3327 coredump_sanitise_path(const char *path)
 3328 {
 3329         size_t i;
 3330 
 3331         /*
 3332          * Only send a subset of ASCII to devd(8) because it
 3333          * might pass these strings to sh -c.
 3334          */
 3335         for (i = 0; path[i]; i++)
 3336                 if (!(isalpha(path[i]) || isdigit(path[i])) &&
 3337                     path[i] != '/' && path[i] != '.' &&
 3338                     path[i] != '-')
 3339                         return (0);
 3340 
 3341         return (1);
 3342 }
 3343 
 3344 /*
 3345  * Dump a process' core.  The main routine does some
 3346  * policy checking, and creates the name of the coredump;
 3347  * then it passes on a vnode and a size limit to the process-specific
 3348  * coredump routine if there is one; if there _is not_ one, it returns
 3349  * ENOSYS; otherwise it returns the error from the process-specific routine.
 3350  */
 3351 
 3352 static int
 3353 coredump(struct thread *td)
 3354 {
 3355         struct proc *p = td->td_proc;
 3356         struct ucred *cred = td->td_ucred;
 3357         struct vnode *vp;
 3358         struct flock lf;
 3359         struct vattr vattr;
 3360         int error, error1, locked;
 3361         struct mount *mp;
 3362         char *name;                     /* name of corefile */
 3363         off_t limit;
 3364         int compress;
 3365         char *data = NULL;
 3366         char *fullpath, *freepath = NULL;
 3367         size_t len;
 3368         static const char comm_name[] = "comm=";
 3369         static const char core_name[] = "core=";
 3370 
 3371 #ifdef COMPRESS_USER_CORES
 3372         compress = compress_user_cores;
 3373 #else
 3374         compress = 0;
 3375 #endif
 3376         PROC_LOCK_ASSERT(p, MA_OWNED);
 3377         MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td);
 3378         _STOPEVENT(p, S_CORE, 0);
 3379 
 3380         if (!do_coredump || (!sugid_coredump && (p->p_flag & P_SUGID) != 0) ||
 3381             (p->p_flag2 & P2_NOTRACE) != 0) {
 3382                 PROC_UNLOCK(p);
 3383                 return (EFAULT);
 3384         }
 3385 
 3386         /*
 3387          * Note that the bulk of limit checking is done after
 3388          * the corefile is created.  The exception is if the limit
 3389          * for corefiles is 0, in which case we don't bother
 3390          * creating the corefile at all.  This layout means that
 3391          * a corefile is truncated instead of not being created,
 3392          * if it is larger than the limit.
 3393          */
 3394         limit = (off_t)lim_cur(p, RLIMIT_CORE);
 3395         if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) {
 3396                 PROC_UNLOCK(p);
 3397                 return (EFBIG);
 3398         }
 3399         PROC_UNLOCK(p);
 3400 
 3401 restart:
 3402         error = corefile_open(p->p_comm, cred->cr_uid, p->p_pid, td, compress,
 3403             &vp, &name);
 3404         if (error != 0)
 3405                 return (error);
 3406 
 3407         /* Don't dump to non-regular files or files with links. */
 3408         if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred) != 0 ||
 3409             vattr.va_nlink != 1) {
 3410                 VOP_UNLOCK(vp, 0);
 3411                 error = EFAULT;
 3412                 goto out;
 3413         }
 3414 
 3415         VOP_UNLOCK(vp, 0);
 3416         lf.l_whence = SEEK_SET;
 3417         lf.l_start = 0;
 3418         lf.l_len = 0;
 3419         lf.l_type = F_WRLCK;
 3420         locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0);
 3421 
 3422         if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
 3423                 lf.l_type = F_UNLCK;
 3424                 if (locked)
 3425                         VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
 3426                 if ((error = vn_close(vp, FWRITE, cred, td)) != 0)
 3427                         goto out;
 3428                 if ((error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH)) != 0)
 3429                         goto out;
 3430                 free(name, M_TEMP);
 3431                 goto restart;
 3432         }
 3433 
 3434         VATTR_NULL(&vattr);
 3435         vattr.va_size = 0;
 3436         if (set_core_nodump_flag)
 3437                 vattr.va_flags = UF_NODUMP;
 3438         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 3439         VOP_SETATTR(vp, &vattr, cred);
 3440         VOP_UNLOCK(vp, 0);
 3441         vn_finished_write(mp);
 3442         PROC_LOCK(p);
 3443         p->p_acflag |= ACORE;
 3444         PROC_UNLOCK(p);
 3445 
 3446         if (p->p_sysent->sv_coredump != NULL) {
 3447                 error = p->p_sysent->sv_coredump(td, vp, limit,
 3448                     compress ? IMGACT_CORE_COMPRESS : 0);
 3449         } else {
 3450                 error = ENOSYS;
 3451         }
 3452 
 3453         if (locked) {
 3454                 lf.l_type = F_UNLCK;
 3455                 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK);
 3456         }
 3457 
 3458         /*
 3459          * Notify the userland helper that a process triggered a core dump.
 3460          * This allows the helper to run an automated debugging session.
 3461          */
 3462         if (error != 0 || coredump_devctl == 0)
 3463                 goto out;
 3464         len = MAXPATHLEN * 2 + sizeof(comm_name) - 1 +
 3465             sizeof(' ') + sizeof(core_name) - 1;
 3466         data = malloc(len, M_TEMP, M_WAITOK);
 3467         if (vn_fullpath_global(td, p->p_textvp, &fullpath, &freepath) != 0)
 3468                 goto out;
 3469         if (!coredump_sanitise_path(fullpath))
 3470                 goto out;
 3471         snprintf(data, len, "%s%s ", comm_name, fullpath);
 3472         free(freepath, M_TEMP);
 3473         freepath = NULL;
 3474         if (vn_fullpath_global(td, vp, &fullpath, &freepath) != 0)
 3475                 goto out;
 3476         if (!coredump_sanitise_path(fullpath))
 3477                 goto out;
 3478         strlcat(data, core_name, len);
 3479         strlcat(data, fullpath, len);
 3480         devctl_notify("kernel", "signal", "coredump", data);
 3481 out:
 3482         error1 = vn_close(vp, FWRITE, cred, td);
 3483         if (error == 0)
 3484                 error = error1;
 3485 #ifdef AUDIT
 3486         audit_proc_coredump(td, name, error);
 3487 #endif
 3488         free(freepath, M_TEMP);
 3489         free(data, M_TEMP);
 3490         free(name, M_TEMP);
 3491         return (error);
 3492 }
 3493 
 3494 /*
 3495  * Nonexistent system call-- signal process (may want to handle it).  Flag
 3496  * error in case process won't see signal immediately (blocked or ignored).
 3497  */
 3498 #ifndef _SYS_SYSPROTO_H_
 3499 struct nosys_args {
 3500         int     dummy;
 3501 };
 3502 #endif
 3503 /* ARGSUSED */
 3504 int
 3505 nosys(td, args)
 3506         struct thread *td;
 3507         struct nosys_args *args;
 3508 {
 3509         struct proc *p = td->td_proc;
 3510 
 3511         PROC_LOCK(p);
 3512         tdsignal(td, SIGSYS);
 3513         PROC_UNLOCK(p);
 3514         return (ENOSYS);
 3515 }
 3516 
 3517 /*
 3518  * Send a SIGIO or SIGURG signal to a process or process group using stored
 3519  * credentials rather than those of the current process.
 3520  */
 3521 void
 3522 pgsigio(sigiop, sig, checkctty)
 3523         struct sigio **sigiop;
 3524         int sig, checkctty;
 3525 {
 3526         ksiginfo_t ksi;
 3527         struct sigio *sigio;
 3528 
 3529         ksiginfo_init(&ksi);
 3530         ksi.ksi_signo = sig;
 3531         ksi.ksi_code = SI_KERNEL;
 3532 
 3533         SIGIO_LOCK();
 3534         sigio = *sigiop;
 3535         if (sigio == NULL) {
 3536                 SIGIO_UNLOCK();
 3537                 return;
 3538         }
 3539         if (sigio->sio_pgid > 0) {
 3540                 PROC_LOCK(sigio->sio_proc);
 3541                 if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred))
 3542                         kern_psignal(sigio->sio_proc, sig);
 3543                 PROC_UNLOCK(sigio->sio_proc);
 3544         } else if (sigio->sio_pgid < 0) {
 3545                 struct proc *p;
 3546 
 3547                 PGRP_LOCK(sigio->sio_pgrp);
 3548                 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
 3549                         PROC_LOCK(p);
 3550                         if (p->p_state == PRS_NORMAL &&
 3551                             CANSIGIO(sigio->sio_ucred, p->p_ucred) &&
 3552                             (checkctty == 0 || (p->p_flag & P_CONTROLT)))
 3553                                 kern_psignal(p, sig);
 3554                         PROC_UNLOCK(p);
 3555                 }
 3556                 PGRP_UNLOCK(sigio->sio_pgrp);
 3557         }
 3558         SIGIO_UNLOCK();
 3559 }
 3560 
 3561 static int
 3562 filt_sigattach(struct knote *kn)
 3563 {
 3564         struct proc *p = curproc;
 3565 
 3566         kn->kn_ptr.p_proc = p;
 3567         kn->kn_flags |= EV_CLEAR;               /* automatically set */
 3568 
 3569         knlist_add(&p->p_klist, kn, 0);
 3570 
 3571         return (0);
 3572 }
 3573 
 3574 static void
 3575 filt_sigdetach(struct knote *kn)
 3576 {
 3577         struct proc *p = kn->kn_ptr.p_proc;
 3578 
 3579         knlist_remove(&p->p_klist, kn, 0);
 3580 }
 3581 
 3582 /*
 3583  * signal knotes are shared with proc knotes, so we apply a mask to
 3584  * the hint in order to differentiate them from process hints.  This
 3585  * could be avoided by using a signal-specific knote list, but probably
 3586  * isn't worth the trouble.
 3587  */
 3588 static int
 3589 filt_signal(struct knote *kn, long hint)
 3590 {
 3591 
 3592         if (hint & NOTE_SIGNAL) {
 3593                 hint &= ~NOTE_SIGNAL;
 3594 
 3595                 if (kn->kn_id == hint)
 3596                         kn->kn_data++;
 3597         }
 3598         return (kn->kn_data != 0);
 3599 }
 3600 
 3601 struct sigacts *
 3602 sigacts_alloc(void)
 3603 {
 3604         struct sigacts *ps;
 3605 
 3606         ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO);
 3607         ps->ps_refcnt = 1;
 3608         mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF);
 3609         return (ps);
 3610 }
 3611 
 3612 void
 3613 sigacts_free(struct sigacts *ps)
 3614 {
 3615 
 3616         if (refcount_release(&ps->ps_refcnt) == 0)
 3617                 return;
 3618         mtx_destroy(&ps->ps_mtx);
 3619         free(ps, M_SUBPROC);
 3620 }
 3621 
 3622 struct sigacts *
 3623 sigacts_hold(struct sigacts *ps)
 3624 {
 3625 
 3626         refcount_acquire(&ps->ps_refcnt);
 3627         return (ps);
 3628 }
 3629 
 3630 void
 3631 sigacts_copy(struct sigacts *dest, struct sigacts *src)
 3632 {
 3633 
 3634         KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest"));
 3635         mtx_lock(&src->ps_mtx);
 3636         bcopy(src, dest, offsetof(struct sigacts, ps_refcnt));
 3637         mtx_unlock(&src->ps_mtx);
 3638 }
 3639 
 3640 int
 3641 sigacts_shared(struct sigacts *ps)
 3642 {
 3643 
 3644         return (ps->ps_refcnt > 1);
 3645 }

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