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.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94
39 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $
40 * $DragonFly: src/sys/kern/kern_sig.c,v 1.67 2007/02/21 15:45:36 corecode Exp $
43 #include "opt_ktrace.h"
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/kernel.h>
48 #include <sys/sysproto.h>
49 #include <sys/signalvar.h>
50 #include <sys/resourcevar.h>
51 #include <sys/vnode.h>
52 #include <sys/event.h>
54 #include <sys/nlookup.h>
55 #include <sys/pioctl.h>
56 #include <sys/systm.h>
58 #include <sys/fcntl.h>
61 #include <sys/ktrace.h>
62 #include <sys/syslog.h>
64 #include <sys/sysent.h>
65 #include <sys/sysctl.h>
66 #include <sys/malloc.h>
67 #include <sys/interrupt.h>
68 #include <sys/unistd.h>
69 #include <sys/kern_syscall.h>
70 #include <sys/vkernel.h>
71 #include <sys/thread2.h>
73 #include <machine/cpu.h>
74 #include <machine/smp.h>
76 static int coredump(struct lwp *, int);
77 static char *expand_name(const char *, uid_t, pid_t);
78 static int dokillpg(int sig, int pgid, int all);
79 static int sig_ffs(sigset_t *set);
80 static int sigprop(int sig);
82 static void signotify_remote(void *arg);
84 static int kern_sigtimedwait(sigset_t set, siginfo_t *info,
85 struct timespec *timeout);
87 static int filt_sigattach(struct knote *kn);
88 static void filt_sigdetach(struct knote *kn);
89 static int filt_signal(struct knote *kn, long hint);
91 struct filterops sig_filtops =
92 { 0, filt_sigattach, filt_sigdetach, filt_signal };
94 static int kern_logsigexit = 1;
95 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
97 "Log processes quitting on abnormal signals to syslog(3)");
100 * Can process p, with pcred pc, send the signal sig to process q?
102 #define CANSIGNAL(q, sig) \
103 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \
104 ((sig) == SIGCONT && (q)->p_session == curproc->p_session))
107 * Policy -- Can real uid ruid with ucred uc send a signal to process q?
109 #define CANSIGIO(ruid, uc, q) \
110 ((uc)->cr_uid == 0 || \
111 (ruid) == (q)->p_ucred->cr_ruid || \
112 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \
113 (ruid) == (q)->p_ucred->cr_uid || \
114 (uc)->cr_uid == (q)->p_ucred->cr_uid)
117 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW,
118 &sugid_coredump, 0, "Enable coredumping set user/group ID processes");
120 static int do_coredump = 1;
121 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
122 &do_coredump, 0, "Enable/Disable coredumps");
125 * Signal properties and actions.
126 * The array below categorizes the signals and their default actions
127 * according to the following properties:
129 #define SA_KILL 0x01 /* terminates process by default */
130 #define SA_CORE 0x02 /* ditto and coredumps */
131 #define SA_STOP 0x04 /* suspend process */
132 #define SA_TTYSTOP 0x08 /* ditto, from tty */
133 #define SA_IGNORE 0x10 /* ignore by default */
134 #define SA_CONT 0x20 /* continue if suspended */
135 #define SA_CANTMASK 0x40 /* non-maskable, catchable */
136 #define SA_CKPT 0x80 /* checkpoint process */
139 static int sigproptbl[NSIG] = {
140 SA_KILL, /* SIGHUP */
141 SA_KILL, /* SIGINT */
142 SA_KILL|SA_CORE, /* SIGQUIT */
143 SA_KILL|SA_CORE, /* SIGILL */
144 SA_KILL|SA_CORE, /* SIGTRAP */
145 SA_KILL|SA_CORE, /* SIGABRT */
146 SA_KILL|SA_CORE, /* SIGEMT */
147 SA_KILL|SA_CORE, /* SIGFPE */
148 SA_KILL, /* SIGKILL */
149 SA_KILL|SA_CORE, /* SIGBUS */
150 SA_KILL|SA_CORE, /* SIGSEGV */
151 SA_KILL|SA_CORE, /* SIGSYS */
152 SA_KILL, /* SIGPIPE */
153 SA_KILL, /* SIGALRM */
154 SA_KILL, /* SIGTERM */
155 SA_IGNORE, /* SIGURG */
156 SA_STOP, /* SIGSTOP */
157 SA_STOP|SA_TTYSTOP, /* SIGTSTP */
158 SA_IGNORE|SA_CONT, /* SIGCONT */
159 SA_IGNORE, /* SIGCHLD */
160 SA_STOP|SA_TTYSTOP, /* SIGTTIN */
161 SA_STOP|SA_TTYSTOP, /* SIGTTOU */
162 SA_IGNORE, /* SIGIO */
163 SA_KILL, /* SIGXCPU */
164 SA_KILL, /* SIGXFSZ */
165 SA_KILL, /* SIGVTALRM */
166 SA_KILL, /* SIGPROF */
167 SA_IGNORE, /* SIGWINCH */
168 SA_IGNORE, /* SIGINFO */
169 SA_KILL, /* SIGUSR1 */
170 SA_KILL, /* SIGUSR2 */
171 SA_IGNORE, /* SIGTHR */
172 SA_CKPT, /* SIGCKPT */
173 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */
211 if (sig > 0 && sig < NSIG)
212 return (sigproptbl[_SIG_IDX(sig)]);
217 sig_ffs(sigset_t *set)
221 for (i = 0; i < _SIG_WORDS; i++)
223 return (ffs(set->__bits[i]) + (i * 32));
228 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact)
230 struct thread *td = curthread;
231 struct proc *p = td->td_proc;
232 struct sigacts *ps = p->p_sigacts;
234 if (sig <= 0 || sig > _SIG_MAXSIG)
238 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
239 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
241 if (SIGISMEMBER(ps->ps_sigonstack, sig))
242 oact->sa_flags |= SA_ONSTACK;
243 if (!SIGISMEMBER(ps->ps_sigintr, sig))
244 oact->sa_flags |= SA_RESTART;
245 if (SIGISMEMBER(ps->ps_sigreset, sig))
246 oact->sa_flags |= SA_RESETHAND;
247 if (SIGISMEMBER(ps->ps_signodefer, sig))
248 oact->sa_flags |= SA_NODEFER;
249 if (SIGISMEMBER(ps->ps_siginfo, sig))
250 oact->sa_flags |= SA_SIGINFO;
251 if (SIGISMEMBER(ps->ps_sigmailbox, sig))
252 oact->sa_flags |= SA_MAILBOX;
253 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDSTOP)
254 oact->sa_flags |= SA_NOCLDSTOP;
255 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDWAIT)
256 oact->sa_flags |= SA_NOCLDWAIT;
260 * Check for invalid requests. KILL and STOP cannot be
263 if (sig == SIGKILL || sig == SIGSTOP) {
264 if (act->sa_handler != SIG_DFL)
267 /* (not needed, SIG_DFL forces action to occur) */
268 if (act->sa_flags & SA_MAILBOX)
274 * Change setting atomically.
278 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
279 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
280 if (act->sa_flags & SA_SIGINFO) {
281 ps->ps_sigact[_SIG_IDX(sig)] =
282 (__sighandler_t *)act->sa_sigaction;
283 SIGADDSET(ps->ps_siginfo, sig);
285 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
286 SIGDELSET(ps->ps_siginfo, sig);
288 if (!(act->sa_flags & SA_RESTART))
289 SIGADDSET(ps->ps_sigintr, sig);
291 SIGDELSET(ps->ps_sigintr, sig);
292 if (act->sa_flags & SA_ONSTACK)
293 SIGADDSET(ps->ps_sigonstack, sig);
295 SIGDELSET(ps->ps_sigonstack, sig);
296 if (act->sa_flags & SA_RESETHAND)
297 SIGADDSET(ps->ps_sigreset, sig);
299 SIGDELSET(ps->ps_sigreset, sig);
300 if (act->sa_flags & SA_NODEFER)
301 SIGADDSET(ps->ps_signodefer, sig);
303 SIGDELSET(ps->ps_signodefer, sig);
304 if (act->sa_flags & SA_MAILBOX)
305 SIGADDSET(ps->ps_sigmailbox, sig);
307 SIGDELSET(ps->ps_sigmailbox, sig);
308 if (sig == SIGCHLD) {
309 if (act->sa_flags & SA_NOCLDSTOP)
310 p->p_procsig->ps_flag |= PS_NOCLDSTOP;
312 p->p_procsig->ps_flag &= ~PS_NOCLDSTOP;
313 if (act->sa_flags & SA_NOCLDWAIT) {
315 * Paranoia: since SA_NOCLDWAIT is implemented
316 * by reparenting the dying child to PID 1 (and
317 * trust it to reap the zombie), PID 1 itself
318 * is forbidden to set SA_NOCLDWAIT.
321 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT;
323 p->p_procsig->ps_flag |= PS_NOCLDWAIT;
325 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT;
329 * Set bit in p_sigignore for signals that are set to SIG_IGN,
330 * and for signals set to SIG_DFL where the default is to
331 * ignore. However, don't put SIGCONT in p_sigignore, as we
332 * have to restart the process.
334 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
335 (sigprop(sig) & SA_IGNORE &&
336 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
337 /* never to be seen again */
338 SIGDELSET(p->p_siglist, sig);
340 /* easier in ksignal */
341 SIGADDSET(p->p_sigignore, sig);
342 SIGDELSET(p->p_sigcatch, sig);
344 SIGDELSET(p->p_sigignore, sig);
345 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
346 SIGDELSET(p->p_sigcatch, sig);
348 SIGADDSET(p->p_sigcatch, sig);
357 sys_sigaction(struct sigaction_args *uap)
359 struct sigaction act, oact;
360 struct sigaction *actp, *oactp;
363 actp = (uap->act != NULL) ? &act : NULL;
364 oactp = (uap->oact != NULL) ? &oact : NULL;
366 error = copyin(uap->act, actp, sizeof(act));
370 error = kern_sigaction(uap->sig, actp, oactp);
371 if (oactp && !error) {
372 error = copyout(oactp, uap->oact, sizeof(oact));
378 * Initialize signal state for process 0;
379 * set to ignore signals that are ignored by default.
382 siginit(struct proc *p)
386 for (i = 1; i <= NSIG; i++)
387 if (sigprop(i) & SA_IGNORE && i != SIGCONT)
388 SIGADDSET(p->p_sigignore, i);
392 * Reset signals for an exec of the specified process.
395 execsigs(struct proc *p)
397 struct sigacts *ps = p->p_sigacts;
402 * Reset caught signals. Held signals remain held
403 * through p_sigmask (unless they were caught,
404 * and are now ignored by default).
406 while (SIGNOTEMPTY(p->p_sigcatch)) {
407 sig = sig_ffs(&p->p_sigcatch);
408 SIGDELSET(p->p_sigcatch, sig);
409 if (sigprop(sig) & SA_IGNORE) {
411 SIGADDSET(p->p_sigignore, sig);
412 SIGDELSET(p->p_siglist, sig);
414 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
417 * Reset stack state to the user stack.
418 * Clear set of signals caught on the signal stack.
420 lp = ONLY_LWP_IN_PROC(p);
421 lp->lwp_sigstk.ss_flags = SS_DISABLE;
422 lp->lwp_sigstk.ss_size = 0;
423 lp->lwp_sigstk.ss_sp = 0;
424 lp->lwp_flag &= ~LWP_ALTSTACK;
426 * Reset no zombies if child dies flag as Solaris does.
428 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT;
432 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc
434 * Manipulate signal mask. This routine is MP SAFE *ONLY* if
438 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset)
440 struct thread *td = curthread;
441 struct lwp *lp = td->td_lwp;
445 *oset = lp->lwp_sigmask;
452 SIGSETOR(lp->lwp_sigmask, *set);
455 SIGSETNAND(lp->lwp_sigmask, *set);
459 lp->lwp_sigmask = *set;
470 * sigprocmask() - MP SAFE
473 sys_sigprocmask(struct sigprocmask_args *uap)
476 sigset_t *setp, *osetp;
479 setp = (uap->set != NULL) ? &set : NULL;
480 osetp = (uap->oset != NULL) ? &oset : NULL;
482 error = copyin(uap->set, setp, sizeof(set));
486 error = kern_sigprocmask(uap->how, setp, osetp);
487 if (osetp && !error) {
488 error = copyout(osetp, uap->oset, sizeof(oset));
494 kern_sigpending(struct __sigset *set)
496 struct thread *td = curthread;
497 struct proc *p = td->td_proc;
505 sys_sigpending(struct sigpending_args *uap)
510 error = kern_sigpending(&set);
513 error = copyout(&set, uap->set, sizeof(set));
518 * Suspend process until signal, providing mask to be set
522 kern_sigsuspend(struct __sigset *set)
524 struct thread *td = curthread;
525 struct lwp *lp = td->td_lwp;
526 struct proc *p = td->td_proc;
527 struct sigacts *ps = p->p_sigacts;
530 * When returning from sigsuspend, we want
531 * the old mask to be restored after the
532 * signal handler has finished. Thus, we
533 * save it here and mark the sigacts structure
536 lp->lwp_oldsigmask = lp->lwp_sigmask;
537 lp->lwp_flag |= LWP_OLDMASK;
540 lp->lwp_sigmask = *set;
541 while (tsleep(ps, PCATCH, "pause", 0) == 0)
543 /* always return EINTR rather than ERESTART... */
548 * Note nonstandard calling convention: libc stub passes mask, not
549 * pointer, to save a copyin.
552 sys_sigsuspend(struct sigsuspend_args *uap)
557 error = copyin(uap->sigmask, &mask, sizeof(mask));
561 error = kern_sigsuspend(&mask);
567 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss)
569 struct thread *td = curthread;
570 struct lwp *lp = td->td_lwp;
571 struct proc *p = td->td_proc;
573 if ((lp->lwp_flag & LWP_ALTSTACK) == 0)
574 lp->lwp_sigstk.ss_flags |= SS_DISABLE;
577 *oss = lp->lwp_sigstk;
580 if (ss->ss_flags & SS_DISABLE) {
581 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK)
583 lp->lwp_flag &= ~LWP_ALTSTACK;
584 lp->lwp_sigstk.ss_flags = ss->ss_flags;
586 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
588 lp->lwp_flag |= LWP_ALTSTACK;
589 lp->lwp_sigstk = *ss;
597 sys_sigaltstack(struct sigaltstack_args *uap)
603 error = copyin(uap->ss, &ss, sizeof(ss));
608 error = kern_sigaltstack(uap->ss ? &ss : NULL,
609 uap->oss ? &oss : NULL);
611 if (error == 0 && uap->oss)
612 error = copyout(&oss, uap->oss, sizeof(*uap->oss));
617 * Common code for kill process group/broadcast kill.
618 * cp is calling process.
625 static int killpg_all_callback(struct proc *p, void *data);
628 dokillpg(int sig, int pgid, int all)
630 struct killpg_info info;
631 struct proc *cp = curproc;
642 allproc_scan(killpg_all_callback, &info);
646 * zero pgid means send to my process group.
654 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
655 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
657 p->p_stat == SZOMB ||
658 (p->p_flag & P_SYSTEM) ||
659 !CANSIGNAL(p, sig)) {
666 lockmgr(&pgrp->pg_lock, LK_RELEASE);
668 return (info.nfound ? 0 : ESRCH);
672 killpg_all_callback(struct proc *p, void *data)
674 struct killpg_info *info = data;
676 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) ||
677 p == curproc || !CANSIGNAL(p, info->sig)) {
682 ksignal(p, info->sig);
687 kern_kill(int sig, int pid)
689 struct thread *td = curthread;
690 struct proc *p = td->td_proc;
692 if ((u_int)sig > _SIG_MAXSIG)
695 /* kill single process */
696 if ((p = pfind(pid)) == NULL)
698 if (!CANSIGNAL(p, sig))
705 case -1: /* broadcast signal */
706 return (dokillpg(sig, 0, 1));
707 case 0: /* signal own process group */
708 return (dokillpg(sig, 0, 0));
709 default: /* negative explicit process group */
710 return (dokillpg(sig, -pid, 0));
716 sys_kill(struct kill_args *uap)
720 error = kern_kill(uap->signum, uap->pid);
726 * Send a signal to a process group.
729 gsignal(int pgid, int sig)
733 if (pgid && (pgrp = pgfind(pgid)))
734 pgsignal(pgrp, sig, 0);
738 * Send a signal to a process group. If checktty is 1,
739 * limit to members which have a controlling terminal.
741 * pg_lock interlocks against a fork that might be in progress, to
742 * ensure that the new child process picks up the signal.
745 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
750 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
751 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
752 if (checkctty == 0 || p->p_flag & P_CONTROLT)
755 lockmgr(&pgrp->pg_lock, LK_RELEASE);
760 * Send a signal caused by a trap to the current process.
761 * If it will be caught immediately, deliver it with correct code.
762 * Otherwise, post it normally.
765 trapsignal(struct lwp *lp, int sig, u_long code)
767 struct proc *p = lp->lwp_proc;
768 struct sigacts *ps = p->p_sigacts;
771 * If we are a virtual kernel running an emulated user process
772 * context, switch back to the virtual kernel context before
773 * trying to post the signal.
775 if (p->p_vkernel && p->p_vkernel->vk_current) {
776 struct trapframe *tf = curthread->td_lwp->lwp_md.md_regs;
782 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
783 !SIGISMEMBER(lp->lwp_sigmask, sig)) {
784 lp->lwp_ru.ru_nsignals++;
786 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
787 ktrpsig(p, sig, ps->ps_sigact[_SIG_IDX(sig)],
788 &lp->lwp_sigmask, code);
790 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
791 &lp->lwp_sigmask, code);
792 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
793 if (!SIGISMEMBER(ps->ps_signodefer, sig))
794 SIGADDSET(lp->lwp_sigmask, sig);
795 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
797 * See kern_sigaction() for origin of this code.
799 SIGDELSET(p->p_sigcatch, sig);
800 if (sig != SIGCONT &&
801 sigprop(sig) & SA_IGNORE)
802 SIGADDSET(p->p_sigignore, sig);
803 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
806 lp->lwp_code = code; /* XXX for core dump/debugger */
807 lp->lwp_sig = sig; /* XXX to verify code */
813 * Send the signal to the process. If the signal has an action, the action
814 * is usually performed by the target process rather than the caller; we add
815 * the signal to the set of pending signals for the process.
818 * o When a stop signal is sent to a sleeping process that takes the
819 * default action, the process is stopped without awakening it.
820 * o SIGCONT restarts stopped processes (or puts them back to sleep)
821 * regardless of the signal action (eg, blocked or ignored).
823 * Other ignored signals are discarded immediately.
826 ksignal(struct proc *p, int sig)
828 /* XXX lwp more intelligent lwp choice needed */
829 struct lwp *lp = FIRST_LWP_IN_PROC(p);
833 if (sig > _SIG_MAXSIG || sig <= 0) {
834 kprintf("ksignal: signal %d\n", sig);
835 panic("ksignal signal number");
839 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
845 * If proc is traced, always give parent a chance;
846 * if signal event is tracked by procfs, give *that*
849 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) {
853 * If the signal is being ignored,
854 * then we forget about it immediately.
855 * (Note: we don't set SIGCONT in p_sigignore,
856 * and if it is set to SIG_IGN,
857 * action will be SIG_DFL here.)
859 if (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT))
861 if (SIGISMEMBER(lp->lwp_sigmask, sig))
863 else if (SIGISMEMBER(p->p_sigcatch, sig))
869 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
870 (p->p_flag & P_TRACED) == 0) {
875 * If continuing, clear any pending STOP signals.
878 SIG_STOPSIGMASK(p->p_siglist);
880 if (prop & SA_STOP) {
882 * If sending a tty stop signal to a member of an orphaned
883 * process group, discard the signal here if the action
884 * is default; don't stop the process below if sleeping,
885 * and don't clear any pending SIGCONT.
887 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
891 SIG_CONTSIGMASK(p->p_siglist);
893 SIGADDSET(p->p_siglist, sig);
896 * Defer further processing for signals which are held,
897 * except that stopped processes must be continued by SIGCONT.
899 if (action == SIG_HOLD) {
900 if ((prop & SA_CONT) == 0 || p->p_stat != SSTOP)
907 /* XXX lwp handle stop/continue */
910 * LWP is in tsleep and not stopped
912 if (lp->lwp_stat == LSSLEEP && p->p_stat != SSTOP) {
914 * If the process is sleeping uninterruptibly
915 * we can't interrupt the sleep... the signal will
916 * be noticed when the process returns through
917 * trap() or syscall().
919 if ((lp->lwp_flag & LWP_SINTR) == 0)
923 * If the process is sleeping and traced, make it runnable
924 * so it can discover the signal in issignal() and stop
927 * If the process is stopped and traced, no further action
930 if (p->p_flag & P_TRACED)
934 * If the process is sleeping and SA_CONT, and the signal
935 * mode is SIG_DFL, then make the process runnable.
937 * However, do *NOT* set LWP_BREAKTSLEEP. We do not want
938 * a SIGCONT to terminate an interruptable tsleep early
939 * and generate a spurious EINTR.
941 if ((prop & SA_CONT) && action == SIG_DFL) {
942 SIGDELSET(p->p_siglist, sig);
947 * If the process is sleeping and receives a STOP signal,
948 * process immediately if possible. All other (caught or
949 * default) signals cause the process to run.
951 if (prop & SA_STOP) {
952 if (action != SIG_DFL)
956 * If a child holding parent blocked, stopping
957 * could cause deadlock. Take no action at this
960 if (p->p_flag & P_PPWAIT)
964 * Do not actually try to manipulate the process while
965 * it is sleeping, simply set SSTOP to indicate that
966 * lwps should stop as soon as they safely can.
968 SIGDELSET(p->p_siglist, sig);
975 * Otherwise the signal can interrupt the sleep.
981 * Process is in tsleep and is stopped
983 if (lp->lwp_stat == LSSLEEP && p->p_stat == SSTOP) {
985 * If the process is stopped and is being traced, then no
986 * further action is necessary.
988 if (p->p_flag & P_TRACED)
992 * If the process is stopped and receives a KILL signal,
993 * make the process runnable.
995 if (sig == SIGKILL) {
1001 * If the process is stopped and receives a CONT signal,
1002 * then try to make the process runnable again.
1004 if (prop & SA_CONT) {
1006 * If SIGCONT is default (or ignored), we continue the
1007 * process but don't leave the signal in p_siglist, as
1008 * it has no further action. If SIGCONT is held, we
1009 * continue the process and leave the signal in
1010 * p_siglist. If the process catches SIGCONT, let it
1011 * handle the signal itself.
1013 if (action == SIG_DFL)
1014 SIGDELSET(p->p_siglist, sig);
1016 if (action == SIG_CATCH)
1022 * If the process is stopped and receives another STOP
1023 * signal, we do not need to stop it again. If we did
1024 * the shell could get confused.
1026 if (prop & SA_STOP) {
1027 SIGDELSET(p->p_siglist, sig);
1032 * Otherwise the process is sleeping interruptably but
1033 * is stopped, just set the LWP_BREAKTSLEEP flag and take
1034 * no further action. The next runnable action will wake
1037 lp->lwp_flag |= LWP_BREAKTSLEEP;
1042 * Otherwise the process is running
1044 * SRUN, SIDL, SZOMB do nothing with the signal,
1045 * other than kicking ourselves if we are running.
1046 * It will either never be noticed, or noticed very soon.
1048 * Note that p_thread may be NULL or may not be completely
1049 * initialized if the process is in the SIDL or SZOMB state.
1051 * For SMP we may have to forward the request to another cpu.
1052 * YYY the MP lock prevents the target process from moving
1053 * to another cpu, see kern/kern_switch.c
1055 * If the target thread is waiting on its message port,
1056 * wakeup the target thread so it can check (or ignore)
1057 * the new signal. YYY needs cleanup.
1059 if (lp == lwkt_preempted_proc()) {
1061 } else if (lp->lwp_stat == LSRUN) {
1062 struct thread *td = lp->lwp_thread;
1065 ("pid %d/%d NULL lwp_thread stat %d flags %08x/%08x",
1066 p->p_pid, lp->lwp_tid, lp->lwp_stat, p->p_flag, lp->lwp_flag));
1069 if (td->td_gd != mycpu)
1070 lwkt_send_ipiq(td->td_gd, signotify_remote, lp);
1073 if (td->td_msgport.mp_flags & MSGPORTF_WAITING)
1080 * Make runnable and break out of any tsleep as well.
1082 lp->lwp_flag |= LWP_BREAKTSLEEP;
1092 * This function is called via an IPI. We will be in a critical section but
1093 * the MP lock will NOT be held. Also note that by the time the ipi message
1094 * gets to us the process 'p' (arg) may no longer be scheduled or even valid.
1097 signotify_remote(void *arg)
1099 struct lwp *lp = arg;
1101 if (lp == lwkt_preempted_proc()) {
1104 struct thread *td = lp->lwp_thread;
1105 if (td->td_msgport.mp_flags & MSGPORTF_WAITING)
1113 proc_stop(struct proc *p, int notify)
1117 p->p_flag &= ~P_WAITED;
1120 (notify && (p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0))
1121 ksignal(p->p_pptr, SIGCHLD);
1125 proc_unstop(struct proc *p)
1127 struct lwp *lp = FIRST_LWP_IN_PROC(p); /* XXX lwp */
1129 p->p_stat = SACTIVE;
1134 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1136 sigset_t savedmask, set;
1137 struct proc *p = curproc;
1138 struct lwp *lp = curthread->td_lwp;
1139 int error, sig, hz, timevalid = 0;
1140 struct timespec rts, ets, ts;
1145 SIG_CANTMASK(waitset);
1146 savedmask = lp->lwp_sigmask;
1149 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1150 timeout->tv_nsec < 1000000000) {
1152 getnanouptime(&rts);
1154 timespecadd(&ets, timeout);
1160 SIGSETAND(set, waitset);
1161 if ((sig = sig_ffs(&set)) != 0) {
1162 SIGFILLSET(lp->lwp_sigmask);
1163 SIGDELSET(lp->lwp_sigmask, sig);
1164 SIG_CANTMASK(lp->lwp_sigmask);
1167 * It may be a STOP signal, in the case, issignal
1168 * returns 0, because we may stop there, and new
1169 * signal can come in, we should restart if we got
1179 * Previous checking got nothing, and we retried but still
1180 * got nothing, we should return the error status.
1186 * POSIX says this must be checked after looking for pending
1194 getnanouptime(&rts);
1195 if (timespeccmp(&rts, &ets, >=)) {
1200 timespecsub(&ts, &rts);
1201 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1202 hz = tvtohz_high(&tv);
1206 lp->lwp_sigmask = savedmask;
1207 SIGSETNAND(lp->lwp_sigmask, waitset);
1208 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1210 if (error == ERESTART) {
1211 /* can not restart a timeout wait. */
1213 } else if (error == EAGAIN) {
1214 /* will calculate timeout by ourself. */
1221 lp->lwp_sigmask = savedmask;
1224 bzero(info, sizeof(*info));
1225 info->si_signo = sig;
1226 SIGDELSET(p->p_siglist, sig); /* take the signal! */
1235 sys_sigtimedwait(struct sigtimedwait_args *uap)
1238 struct timespec *timeout;
1244 error = copyin(uap->timeout, &ts, sizeof(ts));
1251 error = copyin(uap->set, &set, sizeof(set));
1254 error = kern_sigtimedwait(set, &info, timeout);
1258 error = copyout(&info, uap->info, sizeof(info));
1259 /* Repost if we got an error. */
1261 ksignal(curproc, info.si_signo);
1263 uap->sysmsg_result = info.si_signo;
1268 sys_sigwaitinfo(struct sigwaitinfo_args *uap)
1274 error = copyin(uap->set, &set, sizeof(set));
1277 error = kern_sigtimedwait(set, &info, NULL);
1281 error = copyout(&info, uap->info, sizeof(info));
1282 /* Repost if we got an error. */
1284 ksignal(curproc, info.si_signo);
1286 uap->sysmsg_result = info.si_signo;
1291 * If the current process has received a signal that would interrupt a
1292 * system call, return EINTR or ERESTART as appropriate.
1295 iscaught(struct lwp *lp)
1297 struct proc *p = lp->lwp_proc;
1301 if ((sig = CURSIG(lp)) != 0) {
1302 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1307 return(EWOULDBLOCK);
1311 * If the current process has received a signal (should be caught or cause
1312 * termination, should interrupt current syscall), return the signal number.
1313 * Stop signals with default action are processed immediately, then cleared;
1314 * they aren't returned. This is checked after each entry to the system for
1315 * a syscall or trap (though this can usually be done without calling issignal
1316 * by checking the pending signal masks in the CURSIG macro.) The normal call
1319 * This routine is called via CURSIG/__cursig and the MP lock might not be
1320 * held. Obtain the MP lock for the duration of the operation.
1322 * while (sig = CURSIG(curproc))
1326 issignal(struct lwp *lp)
1328 struct proc *p = lp->lwp_proc;
1334 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
1336 mask = p->p_siglist;
1337 SIGSETNAND(mask, lp->lwp_sigmask);
1338 if (p->p_flag & P_PPWAIT)
1339 SIG_STOPSIGMASK(mask);
1340 if (!SIGNOTEMPTY(mask)) { /* no signal to send */
1344 sig = sig_ffs(&mask);
1346 STOPEVENT(p, S_SIG, sig);
1349 * We should see pending but ignored signals
1350 * only if P_TRACED was on when they were posted.
1352 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
1353 SIGDELSET(p->p_siglist, sig);
1356 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) {
1358 * If traced, always stop, and stay stopped until
1359 * released by the parent.
1361 * NOTE: SSTOP may get cleared during the loop,
1362 * but we do not re-notify the parent if we have
1363 * to loop several times waiting for the parent
1364 * to let us continue.
1366 * XXX not sure if this is still true
1372 } while (!trace_req(p) && (p->p_flag & P_TRACED));
1375 * If parent wants us to take the signal,
1376 * then it will leave it in p->p_xstat;
1377 * otherwise we just look for signals again.
1379 SIGDELSET(p->p_siglist, sig); /* clear old signal */
1385 * Put the new signal into p_siglist. If the
1386 * signal is being masked, look for other signals.
1388 SIGADDSET(p->p_siglist, sig);
1389 if (SIGISMEMBER(lp->lwp_sigmask, sig))
1393 * If the traced bit got turned off, go back up
1394 * to the top to rescan signals. This ensures
1395 * that p_sig* and ps_sigact are consistent.
1397 if ((p->p_flag & P_TRACED) == 0)
1401 prop = sigprop(sig);
1404 * Decide whether the signal should be returned.
1405 * Return the signal's number, or fall through
1406 * to clear it from the pending mask.
1408 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
1411 * Don't take default actions on system processes.
1413 if (p->p_pid <= 1) {
1416 * Are you sure you want to ignore SIGSEGV
1419 kprintf("Process (pid %lu) got signal %d\n",
1420 (u_long)p->p_pid, sig);
1422 break; /* == ignore */
1426 * Handle the in-kernel checkpoint action
1428 if (prop & SA_CKPT) {
1429 checkpoint_signal_handler(lp);
1434 * If there is a pending stop signal to process
1435 * with default action, stop here,
1436 * then clear the signal. However,
1437 * if process is member of an orphaned
1438 * process group, ignore tty stop signals.
1440 if (prop & SA_STOP) {
1441 if (p->p_flag & P_TRACED ||
1442 (p->p_pgrp->pg_jobc == 0 &&
1444 break; /* == ignore */
1447 while (p->p_stat == SSTOP) {
1451 } else if (prop & SA_IGNORE) {
1453 * Except for SIGCONT, shouldn't get here.
1454 * Default action is to ignore; drop it.
1456 break; /* == ignore */
1466 * Masking above should prevent us ever trying
1467 * to take action on an ignored signal other
1468 * than SIGCONT, unless process is traced.
1470 if ((prop & SA_CONT) == 0 &&
1471 (p->p_flag & P_TRACED) == 0)
1472 kprintf("issignal\n");
1473 break; /* == ignore */
1477 * This signal has an action, let
1478 * postsig() process it.
1483 SIGDELSET(p->p_siglist, sig); /* take the signal! */
1489 * Take the action for the specified signal
1490 * from the current set of pending signals.
1495 struct lwp *lp = curthread->td_lwp;
1496 struct proc *p = lp->lwp_proc;
1497 struct sigacts *ps = p->p_sigacts;
1499 sigset_t returnmask;
1502 KASSERT(sig != 0, ("postsig"));
1505 * If we are a virtual kernel running an emulated user process
1506 * context, switch back to the virtual kernel context before
1507 * trying to post the signal.
1509 if (p->p_vkernel && p->p_vkernel->vk_current) {
1510 struct trapframe *tf = curthread->td_lwp->lwp_md.md_regs;
1512 vkernel_trap(p, tf);
1515 SIGDELSET(p->p_siglist, sig);
1516 action = ps->ps_sigact[_SIG_IDX(sig)];
1518 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
1519 ktrpsig(p, sig, action, lp->lwp_flag & LWP_OLDMASK ?
1520 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0);
1522 STOPEVENT(p, S_SIG, sig);
1524 if (action == SIG_DFL) {
1526 * Default action, where the default is to kill
1527 * the process. (Other cases were ignored above.)
1533 * If we get here, the signal must be caught.
1535 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig),
1536 ("postsig action"));
1541 * Reset the signal handler if asked to
1543 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
1545 * See kern_sigaction() for origin of this code.
1547 SIGDELSET(p->p_sigcatch, sig);
1548 if (sig != SIGCONT &&
1549 sigprop(sig) & SA_IGNORE)
1550 SIGADDSET(p->p_sigignore, sig);
1551 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1555 * Handle the mailbox case. Copyout to the appropriate
1556 * location but do not generate a signal frame. The system
1557 * call simply returns EINTR and the user is responsible for
1558 * polling the mailbox.
1560 if (SIGISMEMBER(ps->ps_sigmailbox, sig)) {
1562 copyout(&sig_copy, (void *)action, sizeof(int));
1563 curproc->p_flag |= P_MAILBOX;
1569 * Set the signal mask and calculate the mask to restore
1570 * when the signal function returns.
1572 * Special case: user has done a sigsuspend. Here the
1573 * current mask is not of interest, but rather the
1574 * mask from before the sigsuspend is what we want
1575 * restored after the signal processing is completed.
1577 if (lp->lwp_flag & LWP_OLDMASK) {
1578 returnmask = lp->lwp_oldsigmask;
1579 lp->lwp_flag &= ~LWP_OLDMASK;
1581 returnmask = lp->lwp_sigmask;
1584 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
1585 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1586 SIGADDSET(lp->lwp_sigmask, sig);
1589 lp->lwp_ru.ru_nsignals++;
1590 if (lp->lwp_sig != sig) {
1593 code = lp->lwp_code;
1597 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
1604 * Kill the current process for stated reason.
1607 killproc(struct proc *p, char *why)
1609 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n",
1610 p->p_pid, p->p_comm,
1611 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
1612 ksignal(p, SIGKILL);
1616 * Force the current process to exit with the specified signal, dumping core
1617 * if appropriate. We bypass the normal tests for masked and caught signals,
1618 * allowing unrecoverable failures to terminate the process without changing
1619 * signal state. Mark the accounting record with the signal termination.
1620 * If dumping core, save the signal number for the debugger. Calls exit and
1624 sigexit(struct proc *p, int sig)
1626 struct lwp *lp = FIRST_LWP_IN_PROC(p); /* XXX lwp */
1628 p->p_acflag |= AXSIG;
1629 if (sigprop(sig) & SA_CORE) {
1632 * Log signals which would cause core dumps
1633 * (Log as LOG_INFO to appease those who don't want
1635 * XXX : Todo, as well as euid, write out ruid too
1637 if (coredump(lp, sig) == 0)
1639 if (kern_logsigexit)
1641 "pid %d (%s), uid %d: exited on signal %d%s\n",
1642 p->p_pid, p->p_comm,
1643 p->p_ucred ? p->p_ucred->cr_uid : -1,
1645 sig & WCOREFLAG ? " (core dumped)" : "");
1647 exit1(W_EXITCODE(0, sig));
1651 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
1652 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
1653 sizeof(corefilename), "process corefile name format string");
1656 * expand_name(name, uid, pid)
1657 * Expand the name described in corefilename, using name, uid, and pid.
1658 * corefilename is a kprintf-like string, with three format specifiers:
1659 * %N name of process ("name")
1660 * %P process id (pid)
1662 * For example, "%N.core" is the default; they can be disabled completely
1663 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
1664 * This is controlled by the sysctl variable kern.corefile (see above).
1668 expand_name(const char *name, uid_t uid, pid_t pid)
1671 char buf[11]; /* Buffer for pid/uid -- max 4B */
1673 char *format = corefilename;
1676 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
1679 namelen = strlen(name);
1680 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
1682 switch (format[i]) {
1683 case '%': /* Format character */
1685 switch (format[i]) {
1689 case 'N': /* process name */
1690 if ((n + namelen) > MAXPATHLEN) {
1691 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1692 pid, name, uid, temp, name);
1693 kfree(temp, M_TEMP);
1696 memcpy(temp+n, name, namelen);
1699 case 'P': /* process id */
1700 l = ksprintf(buf, "%u", pid);
1701 if ((n + l) > MAXPATHLEN) {
1702 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1703 pid, name, uid, temp, name);
1704 kfree(temp, M_TEMP);
1707 memcpy(temp+n, buf, l);
1710 case 'U': /* user id */
1711 l = ksprintf(buf, "%u", uid);
1712 if ((n + l) > MAXPATHLEN) {
1713 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1714 pid, name, uid, temp, name);
1715 kfree(temp, M_TEMP);
1718 memcpy(temp+n, buf, l);
1722 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
1726 temp[n++] = format[i];
1734 * Dump a process' core. The main routine does some
1735 * policy checking, and creates the name of the coredump;
1736 * then it passes on a vnode and a size limit to the process-specific
1737 * coredump routine if there is one; if there _is not_ one, it returns
1738 * ENOSYS; otherwise it returns the error from the process-specific routine.
1740 * The parameter `lp' is the lwp which triggered the coredump.
1744 coredump(struct lwp *lp, int sig)
1746 struct proc *p = lp->lwp_proc;
1748 struct ucred *cred = p->p_ucred;
1750 struct nlookupdata nd;
1753 char *name; /* name of corefile */
1756 STOPEVENT(p, S_CORE, 0);
1758 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0)
1762 * Note that the bulk of limit checking is done after
1763 * the corefile is created. The exception is if the limit
1764 * for corefiles is 0, in which case we don't bother
1765 * creating the corefile at all. This layout means that
1766 * a corefile is truncated instead of not being created,
1767 * if it is larger than the limit.
1769 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
1773 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
1776 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
1778 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
1779 kfree(name, M_TEMP);
1785 nd.nl_open_vp = NULL;
1789 lf.l_whence = SEEK_SET;
1792 lf.l_type = F_WRLCK;
1793 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
1797 /* Don't dump to non-regular files or files with links. */
1798 if (vp->v_type != VREG ||
1799 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
1805 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1807 VOP_SETATTR(vp, &vattr, cred);
1808 p->p_acflag |= ACORE;
1811 error = p->p_sysent->sv_coredump ?
1812 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS;
1815 lf.l_type = F_UNLCK;
1816 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
1818 error1 = vn_close(vp, FWRITE);
1825 * Nonexistent system call-- signal process (may want to handle it).
1826 * Flag error in case process won't see signal immediately (blocked or ignored).
1830 sys_nosys(struct nosys_args *args)
1832 ksignal(curproc, SIGSYS);
1837 * Send a SIGIO or SIGURG signal to a process or process group using
1838 * stored credentials rather than those of the current process.
1841 pgsigio(struct sigio *sigio, int sig, int checkctty)
1846 if (sigio->sio_pgid > 0) {
1847 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
1849 ksignal(sigio->sio_proc, sig);
1850 } else if (sigio->sio_pgid < 0) {
1853 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE);
1854 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
1855 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
1856 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
1859 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE);
1864 filt_sigattach(struct knote *kn)
1866 struct proc *p = curproc;
1868 kn->kn_ptr.p_proc = p;
1869 kn->kn_flags |= EV_CLEAR; /* automatically set */
1871 /* XXX lock the proc here while adding to the list? */
1872 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
1878 filt_sigdetach(struct knote *kn)
1880 struct proc *p = kn->kn_ptr.p_proc;
1882 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
1886 * signal knotes are shared with proc knotes, so we apply a mask to
1887 * the hint in order to differentiate them from process hints. This
1888 * could be avoided by using a signal-specific knote list, but probably
1889 * isn't worth the trouble.
1892 filt_signal(struct knote *kn, long hint)
1894 if (hint & NOTE_SIGNAL) {
1895 hint &= ~NOTE_SIGNAL;
1897 if (kn->kn_id == hint)
1900 return (kn->kn_data != 0);