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 1.55 2006/10/10 15:40:46 dillon 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/unistd.h>
68 #include <sys/kern_syscall.h>
69 #include <sys/thread2.h>
72 #include <machine/ipl.h>
73 #include <machine/cpu.h>
74 #include <machine/smp.h>
76 static int coredump(struct proc *);
77 static char *expand_name(const char *, uid_t, pid_t);
78 static int killpg(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 (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDSTOP)
252 oact->sa_flags |= SA_NOCLDSTOP;
253 if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDWAIT)
254 oact->sa_flags |= SA_NOCLDWAIT;
257 if ((sig == SIGKILL || sig == SIGSTOP) &&
258 act->sa_handler != SIG_DFL)
262 * Change setting atomically.
266 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
267 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
268 if (act->sa_flags & SA_SIGINFO) {
269 ps->ps_sigact[_SIG_IDX(sig)] =
270 (__sighandler_t *)act->sa_sigaction;
271 SIGADDSET(ps->ps_siginfo, sig);
273 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
274 SIGDELSET(ps->ps_siginfo, sig);
276 if (!(act->sa_flags & SA_RESTART))
277 SIGADDSET(ps->ps_sigintr, sig);
279 SIGDELSET(ps->ps_sigintr, sig);
280 if (act->sa_flags & SA_ONSTACK)
281 SIGADDSET(ps->ps_sigonstack, sig);
283 SIGDELSET(ps->ps_sigonstack, sig);
284 if (act->sa_flags & SA_RESETHAND)
285 SIGADDSET(ps->ps_sigreset, sig);
287 SIGDELSET(ps->ps_sigreset, sig);
288 if (act->sa_flags & SA_NODEFER)
289 SIGADDSET(ps->ps_signodefer, sig);
291 SIGDELSET(ps->ps_signodefer, sig);
292 if (sig == SIGCHLD) {
293 if (act->sa_flags & SA_NOCLDSTOP)
294 p->p_procsig->ps_flag |= PS_NOCLDSTOP;
296 p->p_procsig->ps_flag &= ~PS_NOCLDSTOP;
297 if (act->sa_flags & SA_NOCLDWAIT) {
299 * Paranoia: since SA_NOCLDWAIT is implemented
300 * by reparenting the dying child to PID 1 (and
301 * trust it to reap the zombie), PID 1 itself
302 * is forbidden to set SA_NOCLDWAIT.
305 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT;
307 p->p_procsig->ps_flag |= PS_NOCLDWAIT;
309 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT;
313 * Set bit in p_sigignore for signals that are set to SIG_IGN,
314 * and for signals set to SIG_DFL where the default is to
315 * ignore. However, don't put SIGCONT in p_sigignore, as we
316 * have to restart the process.
318 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
319 (sigprop(sig) & SA_IGNORE &&
320 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
321 /* never to be seen again */
322 SIGDELSET(p->p_siglist, sig);
324 /* easier in ksignal */
325 SIGADDSET(p->p_sigignore, sig);
326 SIGDELSET(p->p_sigcatch, sig);
328 SIGDELSET(p->p_sigignore, sig);
329 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
330 SIGDELSET(p->p_sigcatch, sig);
332 SIGADDSET(p->p_sigcatch, sig);
341 sys_sigaction(struct sigaction_args *uap)
343 struct sigaction act, oact;
344 struct sigaction *actp, *oactp;
347 actp = (uap->act != NULL) ? &act : NULL;
348 oactp = (uap->oact != NULL) ? &oact : NULL;
350 error = copyin(uap->act, actp, sizeof(act));
354 error = kern_sigaction(uap->sig, actp, oactp);
355 if (oactp && !error) {
356 error = copyout(oactp, uap->oact, sizeof(oact));
362 * Initialize signal state for process 0;
363 * set to ignore signals that are ignored by default.
366 siginit(struct proc *p)
370 for (i = 1; i <= NSIG; i++)
371 if (sigprop(i) & SA_IGNORE && i != SIGCONT)
372 SIGADDSET(p->p_sigignore, i);
376 * Reset signals for an exec of the specified process.
379 execsigs(struct proc *p)
381 struct sigacts *ps = p->p_sigacts;
385 * Reset caught signals. Held signals remain held
386 * through p_sigmask (unless they were caught,
387 * and are now ignored by default).
389 while (SIGNOTEMPTY(p->p_sigcatch)) {
390 sig = sig_ffs(&p->p_sigcatch);
391 SIGDELSET(p->p_sigcatch, sig);
392 if (sigprop(sig) & SA_IGNORE) {
394 SIGADDSET(p->p_sigignore, sig);
395 SIGDELSET(p->p_siglist, sig);
397 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
400 * Reset stack state to the user stack.
401 * Clear set of signals caught on the signal stack.
403 p->p_sigstk.ss_flags = SS_DISABLE;
404 p->p_sigstk.ss_size = 0;
405 p->p_sigstk.ss_sp = 0;
406 p->p_flag &= ~P_ALTSTACK;
408 * Reset no zombies if child dies flag as Solaris does.
410 p->p_procsig->ps_flag &= ~PS_NOCLDWAIT;
414 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc
416 * Manipulate signal mask. This routine is MP SAFE *ONLY* if
420 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset)
422 struct thread *td = curthread;
423 struct proc *p = td->td_proc;
427 *oset = p->p_sigmask;
434 SIGSETOR(p->p_sigmask, *set);
437 SIGSETNAND(p->p_sigmask, *set);
452 * sigprocmask() - MP SAFE
455 sys_sigprocmask(struct sigprocmask_args *uap)
458 sigset_t *setp, *osetp;
461 setp = (uap->set != NULL) ? &set : NULL;
462 osetp = (uap->oset != NULL) ? &oset : NULL;
464 error = copyin(uap->set, setp, sizeof(set));
468 error = kern_sigprocmask(uap->how, setp, osetp);
469 if (osetp && !error) {
470 error = copyout(osetp, uap->oset, sizeof(oset));
476 kern_sigpending(struct __sigset *set)
478 struct thread *td = curthread;
479 struct proc *p = td->td_proc;
487 sys_sigpending(struct sigpending_args *uap)
492 error = kern_sigpending(&set);
495 error = copyout(&set, uap->set, sizeof(set));
500 * Suspend process until signal, providing mask to be set
504 kern_sigsuspend(struct __sigset *set)
506 struct thread *td = curthread;
507 struct proc *p = td->td_proc;
508 struct sigacts *ps = p->p_sigacts;
511 * When returning from sigsuspend, we want
512 * the old mask to be restored after the
513 * signal handler has finished. Thus, we
514 * save it here and mark the sigacts structure
517 p->p_oldsigmask = p->p_sigmask;
518 p->p_flag |= P_OLDMASK;
522 while (tsleep(ps, PCATCH, "pause", 0) == 0)
524 /* always return EINTR rather than ERESTART... */
529 * Note nonstandard calling convention: libc stub passes mask, not
530 * pointer, to save a copyin.
533 sys_sigsuspend(struct sigsuspend_args *uap)
538 error = copyin(uap->sigmask, &mask, sizeof(mask));
542 error = kern_sigsuspend(&mask);
548 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss)
550 struct thread *td = curthread;
551 struct proc *p = td->td_proc;
553 if ((p->p_flag & P_ALTSTACK) == 0)
554 p->p_sigstk.ss_flags |= SS_DISABLE;
560 if (ss->ss_flags & SS_DISABLE) {
561 if (p->p_sigstk.ss_flags & SS_ONSTACK)
563 p->p_flag &= ~P_ALTSTACK;
564 p->p_sigstk.ss_flags = ss->ss_flags;
566 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
568 p->p_flag |= P_ALTSTACK;
577 sys_sigaltstack(struct sigaltstack_args *uap)
583 error = copyin(uap->ss, &ss, sizeof(ss));
588 error = kern_sigaltstack(uap->ss ? &ss : NULL,
589 uap->oss ? &oss : NULL);
591 if (error == 0 && uap->oss)
592 error = copyout(&oss, uap->oss, sizeof(*uap->oss));
597 * Common code for kill process group/broadcast kill.
598 * cp is calling process.
605 static int killpg_all_callback(struct proc *p, void *data);
608 killpg(int sig, int pgid, int all)
610 struct killpg_info info;
611 struct proc *cp = curproc;
622 allproc_scan(killpg_all_callback, &info);
626 * zero pgid means send to my process group.
634 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
635 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
637 (p->p_flag & (P_SYSTEM | P_ZOMBIE)) ||
638 !CANSIGNAL(p, sig)) {
645 lockmgr(&pgrp->pg_lock, LK_RELEASE);
647 return (info.nfound ? 0 : ESRCH);
651 killpg_all_callback(struct proc *p, void *data)
653 struct killpg_info *info = data;
655 if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) ||
656 p == curproc || !CANSIGNAL(p, info->sig)) {
661 ksignal(p, info->sig);
666 kern_kill(int sig, int pid)
668 struct thread *td = curthread;
669 struct proc *p = td->td_proc;
671 if ((u_int)sig > _SIG_MAXSIG)
674 /* kill single process */
675 if ((p = pfind(pid)) == NULL)
677 if (!CANSIGNAL(p, sig))
684 case -1: /* broadcast signal */
685 return (killpg(sig, 0, 1));
686 case 0: /* signal own process group */
687 return (killpg(sig, 0, 0));
688 default: /* negative explicit process group */
689 return (killpg(sig, -pid, 0));
695 sys_kill(struct kill_args *uap)
699 error = kern_kill(uap->signum, uap->pid);
705 * Send a signal to a process group.
708 gsignal(int pgid, int sig)
712 if (pgid && (pgrp = pgfind(pgid)))
713 pgsignal(pgrp, sig, 0);
717 * Send a signal to a process group. If checktty is 1,
718 * limit to members which have a controlling terminal.
720 * pg_lock interlocks against a fork that might be in progress, to
721 * ensure that the new child process picks up the signal.
724 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
729 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
730 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
731 if (checkctty == 0 || p->p_flag & P_CONTROLT)
734 lockmgr(&pgrp->pg_lock, LK_RELEASE);
739 * Send a signal caused by a trap to the current process.
740 * If it will be caught immediately, deliver it with correct code.
741 * Otherwise, post it normally.
744 trapsignal(struct proc *p, int sig, u_long code)
746 struct sigacts *ps = p->p_sigacts;
748 if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
749 !SIGISMEMBER(p->p_sigmask, sig)) {
750 p->p_stats->p_ru.ru_nsignals++;
752 if (KTRPOINT(p->p_thread, KTR_PSIG))
753 ktrpsig(p, sig, ps->ps_sigact[_SIG_IDX(sig)],
754 &p->p_sigmask, code);
756 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
757 &p->p_sigmask, code);
758 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
759 if (!SIGISMEMBER(ps->ps_signodefer, sig))
760 SIGADDSET(p->p_sigmask, sig);
761 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
763 * See kern_sigaction() for origin of this code.
765 SIGDELSET(p->p_sigcatch, sig);
766 if (sig != SIGCONT &&
767 sigprop(sig) & SA_IGNORE)
768 SIGADDSET(p->p_sigignore, sig);
769 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
772 p->p_code = code; /* XXX for core dump/debugger */
773 p->p_sig = sig; /* XXX to verify code */
779 * Send the signal to the process. If the signal has an action, the action
780 * is usually performed by the target process rather than the caller; we add
781 * the signal to the set of pending signals for the process.
784 * o When a stop signal is sent to a sleeping process that takes the
785 * default action, the process is stopped without awakening it.
786 * o SIGCONT restarts stopped processes (or puts them back to sleep)
787 * regardless of the signal action (eg, blocked or ignored).
789 * Other ignored signals are discarded immediately.
792 ksignal(struct proc *p, int sig)
794 struct lwp *lp = &p->p_lwp;
798 if (sig > _SIG_MAXSIG || sig <= 0) {
799 printf("ksignal: signal %d\n", sig);
800 panic("ksignal signal number");
804 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
810 * If proc is traced, always give parent a chance;
811 * if signal event is tracked by procfs, give *that*
814 if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) {
818 * If the signal is being ignored,
819 * then we forget about it immediately.
820 * (Note: we don't set SIGCONT in p_sigignore,
821 * and if it is set to SIG_IGN,
822 * action will be SIG_DFL here.)
824 if (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT))
826 if (SIGISMEMBER(p->p_sigmask, sig))
828 else if (SIGISMEMBER(p->p_sigcatch, sig))
834 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
835 (p->p_flag & P_TRACED) == 0) {
840 * If continuing, clear any pending STOP signals.
843 SIG_STOPSIGMASK(p->p_siglist);
845 if (prop & SA_STOP) {
847 * If sending a tty stop signal to a member of an orphaned
848 * process group, discard the signal here if the action
849 * is default; don't stop the process below if sleeping,
850 * and don't clear any pending SIGCONT.
852 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
856 SIG_CONTSIGMASK(p->p_siglist);
858 SIGADDSET(p->p_siglist, sig);
861 * Defer further processing for signals which are held,
862 * except that stopped processes must be continued by SIGCONT.
864 if (action == SIG_HOLD) {
865 if ((prop & SA_CONT) == 0 || (p->p_flag & P_STOPPED) == 0)
872 * Process is in tsleep and not stopped
874 if (p->p_stat == SSLEEP && (p->p_flag & P_STOPPED) == 0) {
876 * If the process is sleeping uninterruptibly
877 * we can't interrupt the sleep... the signal will
878 * be noticed when the process returns through
879 * trap() or syscall().
881 if ((p->p_flag & P_SINTR) == 0)
885 * If the process is sleeping and traced, make it runnable
886 * so it can discover the signal in issignal() and stop
889 * If the process is stopped and traced, no further action
892 if (p->p_flag & P_TRACED)
896 * If the process is sleeping and SA_CONT, and the signal
897 * mode is SIG_DFL, then make the process runnable.
899 * However, do *NOT* set P_BREAKTSLEEP. We do not want
900 * a SIGCONT to terminate an interruptable tsleep early
901 * and generate a spurious EINTR.
903 if ((prop & SA_CONT) && action == SIG_DFL) {
904 SIGDELSET(p->p_siglist, sig);
909 * If the process is sleeping and receives a STOP signal,
910 * process immediately if possible. All other (caught or
911 * default) signals cause the process to run.
913 if (prop & SA_STOP) {
914 if (action != SIG_DFL)
918 * If a child holding parent blocked, stopping
919 * could cause deadlock. Take no action at this
922 if (p->p_flag & P_PPWAIT)
926 * Do not actually try to manipulate the process
927 * while it is sleeping, simply set P_STOPPED to
928 * indicate that it should stop as soon as it safely
931 SIGDELSET(p->p_siglist, sig);
932 p->p_flag |= P_STOPPED;
933 p->p_flag &= ~P_WAITED;
936 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0)
937 ksignal(p->p_pptr, SIGCHLD);
942 * Otherwise the signal can interrupt the sleep.
948 * Process is in tsleep and is stopped
950 if (p->p_stat == SSLEEP && (p->p_flag & P_STOPPED)) {
952 * If the process is stopped and is being traced, then no
953 * further action is necessary.
955 if (p->p_flag & P_TRACED)
959 * If the process is stopped and receives a KILL signal,
960 * make the process runnable.
966 * If the process is stopped and receives a CONT signal,
967 * then try to make the process runnable again.
969 if (prop & SA_CONT) {
971 * If SIGCONT is default (or ignored), we continue the
972 * process but don't leave the signal in p_siglist, as
973 * it has no further action. If SIGCONT is held, we
974 * continue the process and leave the signal in
975 * p_siglist. If the process catches SIGCONT, let it
976 * handle the signal itself.
978 if (action == SIG_DFL)
979 SIGDELSET(p->p_siglist, sig);
980 if (action == SIG_CATCH)
984 * Make runnable but do not break a tsleep unless
985 * some other signal was pending.
991 * If the process is stopped and receives another STOP
992 * signal, we do not need to stop it again. If we did
993 * the shell could get confused.
995 if (prop & SA_STOP) {
996 SIGDELSET(p->p_siglist, sig);
1001 * Otherwise the process is sleeping interruptably but
1002 * is stopped, just set the P_BREAKTSLEEP flag and take
1003 * no further action. The next runnable action will wake
1006 p->p_flag |= P_BREAKTSLEEP;
1011 * Otherwise the process is running
1013 * SRUN, SIDL, SZOMB do nothing with the signal,
1014 * other than kicking ourselves if we are running.
1015 * It will either never be noticed, or noticed very soon.
1017 * Note that p_thread may be NULL or may not be completely
1018 * initialized if the process is in the SIDL or SZOMB state.
1020 * For SMP we may have to forward the request to another cpu.
1021 * YYY the MP lock prevents the target process from moving
1022 * to another cpu, see kern/kern_switch.c
1024 * If the target thread is waiting on its message port,
1025 * wakeup the target thread so it can check (or ignore)
1026 * the new signal. YYY needs cleanup.
1028 if (lp == lwkt_preempted_proc()) {
1030 } else if (p->p_stat == SRUN) {
1031 struct thread *td = p->p_thread;
1034 ("pid %d NULL p_thread stat %d flags %08x",
1035 p->p_pid, p->p_stat, p->p_flag));
1038 if (td->td_gd != mycpu)
1039 lwkt_send_ipiq(td->td_gd, signotify_remote, lp);
1042 if (td->td_msgport.mp_flags & MSGPORTF_WAITING)
1049 * Make runnable and break out of any tsleep as well.
1051 p->p_flag |= P_BREAKTSLEEP;
1061 * This function is called via an IPI. We will be in a critical section but
1062 * the MP lock will NOT be held. Also note that by the time the ipi message
1063 * gets to us the process 'p' (arg) may no longer be scheduled or even valid.
1066 signotify_remote(void *arg)
1068 struct lwp *lp = arg;
1070 if (lp == lwkt_preempted_proc()) {
1073 struct thread *td = lp->lwp_thread;
1074 if (td->td_msgport.mp_flags & MSGPORTF_WAITING)
1082 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1084 sigset_t savedmask, set;
1085 struct proc *p = curproc;
1086 int error, sig, hz, timevalid = 0;
1087 struct timespec rts, ets, ts;
1092 SIG_CANTMASK(waitset);
1093 savedmask = p->p_sigmask;
1096 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1097 timeout->tv_nsec < 1000000000) {
1099 getnanouptime(&rts);
1101 timespecadd(&ets, timeout);
1107 SIGSETAND(set, waitset);
1108 if ((sig = sig_ffs(&set)) != 0) {
1109 SIGFILLSET(p->p_sigmask);
1110 SIGDELSET(p->p_sigmask, sig);
1111 SIG_CANTMASK(p->p_sigmask);
1114 * It may be a STOP signal, in the case, issignal
1115 * returns 0, because we may stop there, and new
1116 * signal can come in, we should restart if we got
1126 * Previous checking got nothing, and we retried but still
1127 * got nothing, we should return the error status.
1133 * POSIX says this must be checked after looking for pending
1141 getnanouptime(&rts);
1142 if (timespeccmp(&rts, &ets, >=)) {
1147 timespecsub(&ts, &rts);
1148 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1149 hz = tvtohz_high(&tv);
1153 p->p_sigmask = savedmask;
1154 SIGSETNAND(p->p_sigmask, waitset);
1155 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1157 if (error == ERESTART) {
1158 /* can not restart a timeout wait. */
1160 } else if (error == EAGAIN) {
1161 /* will calculate timeout by ourself. */
1168 p->p_sigmask = savedmask;
1171 bzero(info, sizeof(*info));
1172 info->si_signo = sig;
1173 SIGDELSET(p->p_siglist, sig); /* take the signal! */
1182 sys_sigtimedwait(struct sigtimedwait_args *uap)
1185 struct timespec *timeout;
1191 error = copyin(uap->timeout, &ts, sizeof(ts));
1198 error = copyin(uap->set, &set, sizeof(set));
1201 error = kern_sigtimedwait(set, &info, timeout);
1205 error = copyout(&info, uap->info, sizeof(info));
1206 /* Repost if we got an error. */
1208 ksignal(curproc, info.si_signo);
1210 uap->sysmsg_result = info.si_signo;
1215 sys_sigwaitinfo(struct sigwaitinfo_args *uap)
1221 error = copyin(uap->set, &set, sizeof(set));
1224 error = kern_sigtimedwait(set, &info, NULL);
1228 error = copyout(&info, uap->info, sizeof(info));
1229 /* Repost if we got an error. */
1231 ksignal(curproc, info.si_signo);
1233 uap->sysmsg_result = info.si_signo;
1238 * If the current process has received a signal that would interrupt a
1239 * system call, return EINTR or ERESTART as appropriate.
1242 iscaught(struct proc *p)
1247 if ((sig = CURSIG(p)) != 0) {
1248 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1253 return(EWOULDBLOCK);
1257 * If the current process has received a signal (should be caught or cause
1258 * termination, should interrupt current syscall), return the signal number.
1259 * Stop signals with default action are processed immediately, then cleared;
1260 * they aren't returned. This is checked after each entry to the system for
1261 * a syscall or trap (though this can usually be done without calling issignal
1262 * by checking the pending signal masks in the CURSIG macro.) The normal call
1265 * This routine is called via CURSIG/__cursig and the MP lock might not be
1266 * held. Obtain the MP lock for the duration of the operation.
1268 * while (sig = CURSIG(curproc))
1272 issignal(struct proc *p)
1279 int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG);
1281 mask = p->p_siglist;
1282 SIGSETNAND(mask, p->p_sigmask);
1283 if (p->p_flag & P_PPWAIT)
1284 SIG_STOPSIGMASK(mask);
1285 if (!SIGNOTEMPTY(mask)) { /* no signal to send */
1289 sig = sig_ffs(&mask);
1291 STOPEVENT(p, S_SIG, sig);
1294 * We should see pending but ignored signals
1295 * only if P_TRACED was on when they were posted.
1297 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
1298 SIGDELSET(p->p_siglist, sig);
1301 if ((p->p_flag & P_TRACED) && (p->p_flag & P_PPWAIT) == 0) {
1303 * If traced, always stop, and stay stopped until
1304 * released by the parent.
1306 * NOTE: P_STOPPED may get cleared during the loop,
1307 * but we do not re-notify the parent if we have
1308 * to loop several times waiting for the parent
1309 * to let us continue.
1312 p->p_flag |= P_STOPPED;
1313 p->p_flag &= ~P_WAITED;
1314 ksignal(p->p_pptr, SIGCHLD);
1317 } while (!trace_req(p) && (p->p_flag & P_TRACED));
1318 p->p_flag &= ~P_STOPPED;
1321 * If parent wants us to take the signal,
1322 * then it will leave it in p->p_xstat;
1323 * otherwise we just look for signals again.
1325 SIGDELSET(p->p_siglist, sig); /* clear old signal */
1331 * Put the new signal into p_siglist. If the
1332 * signal is being masked, look for other signals.
1334 SIGADDSET(p->p_siglist, sig);
1335 if (SIGISMEMBER(p->p_sigmask, sig))
1339 * If the traced bit got turned off, go back up
1340 * to the top to rescan signals. This ensures
1341 * that p_sig* and ps_sigact are consistent.
1343 if ((p->p_flag & P_TRACED) == 0)
1347 prop = sigprop(sig);
1350 * Decide whether the signal should be returned.
1351 * Return the signal's number, or fall through
1352 * to clear it from the pending mask.
1354 switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
1357 * Don't take default actions on system processes.
1359 if (p->p_pid <= 1) {
1362 * Are you sure you want to ignore SIGSEGV
1365 printf("Process (pid %lu) got signal %d\n",
1366 (u_long)p->p_pid, sig);
1368 break; /* == ignore */
1372 * Handle the in-kernel checkpoint action
1374 if (prop & SA_CKPT) {
1375 checkpoint_signal_handler(p);
1380 * If there is a pending stop signal to process
1381 * with default action, stop here,
1382 * then clear the signal. However,
1383 * if process is member of an orphaned
1384 * process group, ignore tty stop signals.
1386 if (prop & SA_STOP) {
1387 if (p->p_flag & P_TRACED ||
1388 (p->p_pgrp->pg_jobc == 0 &&
1390 break; /* == ignore */
1392 p->p_flag |= P_STOPPED;
1393 p->p_flag &= ~P_WAITED;
1395 if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0)
1396 ksignal(p->p_pptr, SIGCHLD);
1397 while (p->p_flag & P_STOPPED) {
1401 } else if (prop & SA_IGNORE) {
1403 * Except for SIGCONT, shouldn't get here.
1404 * Default action is to ignore; drop it.
1406 break; /* == ignore */
1416 * Masking above should prevent us ever trying
1417 * to take action on an ignored signal other
1418 * than SIGCONT, unless process is traced.
1420 if ((prop & SA_CONT) == 0 &&
1421 (p->p_flag & P_TRACED) == 0)
1422 printf("issignal\n");
1423 break; /* == ignore */
1427 * This signal has an action, let
1428 * postsig() process it.
1433 SIGDELSET(p->p_siglist, sig); /* take the signal! */
1439 * Take the action for the specified signal
1440 * from the current set of pending signals.
1445 struct thread *td = curthread;
1446 struct proc *p = td->td_proc;
1447 struct sigacts *ps = p->p_sigacts;
1449 sigset_t returnmask;
1452 KASSERT(sig != 0, ("postsig"));
1454 SIGDELSET(p->p_siglist, sig);
1455 action = ps->ps_sigact[_SIG_IDX(sig)];
1457 if (KTRPOINT(td, KTR_PSIG))
1458 ktrpsig(p, sig, action, p->p_flag & P_OLDMASK ?
1459 &p->p_oldsigmask : &p->p_sigmask, 0);
1461 STOPEVENT(p, S_SIG, sig);
1463 if (action == SIG_DFL) {
1465 * Default action, where the default is to kill
1466 * the process. (Other cases were ignored above.)
1472 * If we get here, the signal must be caught.
1474 KASSERT(action != SIG_IGN && !SIGISMEMBER(p->p_sigmask, sig),
1475 ("postsig action"));
1477 * Set the new mask value and also defer further
1478 * occurrences of this signal.
1480 * Special case: user has done a sigsuspend. Here the
1481 * current mask is not of interest, but rather the
1482 * mask from before the sigsuspend is what we want
1483 * restored after the signal processing is completed.
1486 if (p->p_flag & P_OLDMASK) {
1487 returnmask = p->p_oldsigmask;
1488 p->p_flag &= ~P_OLDMASK;
1490 returnmask = p->p_sigmask;
1493 SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
1494 if (!SIGISMEMBER(ps->ps_signodefer, sig))
1495 SIGADDSET(p->p_sigmask, sig);
1497 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
1499 * See kern_sigaction() for origin of this code.
1501 SIGDELSET(p->p_sigcatch, sig);
1502 if (sig != SIGCONT &&
1503 sigprop(sig) & SA_IGNORE)
1504 SIGADDSET(p->p_sigignore, sig);
1505 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
1508 p->p_stats->p_ru.ru_nsignals++;
1509 if (p->p_sig != sig) {
1516 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
1521 * Kill the current process for stated reason.
1524 killproc(struct proc *p, char *why)
1526 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm,
1527 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
1528 ksignal(p, SIGKILL);
1532 * Force the current process to exit with the specified signal, dumping core
1533 * if appropriate. We bypass the normal tests for masked and caught signals,
1534 * allowing unrecoverable failures to terminate the process without changing
1535 * signal state. Mark the accounting record with the signal termination.
1536 * If dumping core, save the signal number for the debugger. Calls exit and
1540 sigexit(struct proc *p, int sig)
1542 p->p_acflag |= AXSIG;
1543 if (sigprop(sig) & SA_CORE) {
1546 * Log signals which would cause core dumps
1547 * (Log as LOG_INFO to appease those who don't want
1549 * XXX : Todo, as well as euid, write out ruid too
1551 if (coredump(p) == 0)
1553 if (kern_logsigexit)
1555 "pid %d (%s), uid %d: exited on signal %d%s\n",
1556 p->p_pid, p->p_comm,
1557 p->p_ucred ? p->p_ucred->cr_uid : -1,
1559 sig & WCOREFLAG ? " (core dumped)" : "");
1561 exit1(W_EXITCODE(0, sig));
1565 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
1566 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
1567 sizeof(corefilename), "process corefile name format string");
1570 * expand_name(name, uid, pid)
1571 * Expand the name described in corefilename, using name, uid, and pid.
1572 * corefilename is a printf-like string, with three format specifiers:
1573 * %N name of process ("name")
1574 * %P process id (pid)
1576 * For example, "%N.core" is the default; they can be disabled completely
1577 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
1578 * This is controlled by the sysctl variable kern.corefile (see above).
1582 expand_name(const char *name, uid_t uid, pid_t pid)
1585 char buf[11]; /* Buffer for pid/uid -- max 4B */
1587 char *format = corefilename;
1590 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
1593 namelen = strlen(name);
1594 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
1596 switch (format[i]) {
1597 case '%': /* Format character */
1599 switch (format[i]) {
1603 case 'N': /* process name */
1604 if ((n + namelen) > MAXPATHLEN) {
1605 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1606 pid, name, uid, temp, name);
1607 kfree(temp, M_TEMP);
1610 memcpy(temp+n, name, namelen);
1613 case 'P': /* process id */
1614 l = sprintf(buf, "%u", pid);
1615 if ((n + l) > MAXPATHLEN) {
1616 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1617 pid, name, uid, temp, name);
1618 kfree(temp, M_TEMP);
1621 memcpy(temp+n, buf, l);
1624 case 'U': /* user id */
1625 l = sprintf(buf, "%u", uid);
1626 if ((n + l) > MAXPATHLEN) {
1627 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
1628 pid, name, uid, temp, name);
1629 kfree(temp, M_TEMP);
1632 memcpy(temp+n, buf, l);
1636 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
1640 temp[n++] = format[i];
1648 * Dump a process' core. The main routine does some
1649 * policy checking, and creates the name of the coredump;
1650 * then it passes on a vnode and a size limit to the process-specific
1651 * coredump routine if there is one; if there _is not_ one, it returns
1652 * ENOSYS; otherwise it returns the error from the process-specific routine.
1656 coredump(struct proc *p)
1659 struct ucred *cred = p->p_ucred;
1661 struct nlookupdata nd;
1664 char *name; /* name of corefile */
1667 STOPEVENT(p, S_CORE, 0);
1669 if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0)
1673 * Note that the bulk of limit checking is done after
1674 * the corefile is created. The exception is if the limit
1675 * for corefiles is 0, in which case we don't bother
1676 * creating the corefile at all. This layout means that
1677 * a corefile is truncated instead of not being created,
1678 * if it is larger than the limit.
1680 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
1684 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
1687 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
1689 error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
1690 kfree(name, M_TEMP);
1696 nd.nl_open_vp = NULL;
1700 lf.l_whence = SEEK_SET;
1703 lf.l_type = F_WRLCK;
1704 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
1708 /* Don't dump to non-regular files or files with links. */
1709 if (vp->v_type != VREG ||
1710 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
1716 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1718 VOP_SETATTR(vp, &vattr, cred);
1719 p->p_acflag |= ACORE;
1722 error = p->p_sysent->sv_coredump ?
1723 p->p_sysent->sv_coredump(p, vp, limit) : ENOSYS;
1726 lf.l_type = F_UNLCK;
1727 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
1729 error1 = vn_close(vp, FWRITE);
1736 * Nonexistent system call-- signal process (may want to handle it).
1737 * Flag error in case process won't see signal immediately (blocked or ignored).
1741 sys_nosys(struct nosys_args *args)
1743 ksignal(curproc, SIGSYS);
1748 * Send a SIGIO or SIGURG signal to a process or process group using
1749 * stored credentials rather than those of the current process.
1752 pgsigio(struct sigio *sigio, int sig, int checkctty)
1757 if (sigio->sio_pgid > 0) {
1758 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
1760 ksignal(sigio->sio_proc, sig);
1761 } else if (sigio->sio_pgid < 0) {
1764 lockmgr(&sigio->sio_pgrp->pg_lock, LK_EXCLUSIVE);
1765 LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) {
1766 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
1767 (checkctty == 0 || (p->p_flag & P_CONTROLT)))
1770 lockmgr(&sigio->sio_pgrp->pg_lock, LK_RELEASE);
1775 filt_sigattach(struct knote *kn)
1777 struct proc *p = curproc;
1779 kn->kn_ptr.p_proc = p;
1780 kn->kn_flags |= EV_CLEAR; /* automatically set */
1782 /* XXX lock the proc here while adding to the list? */
1783 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
1789 filt_sigdetach(struct knote *kn)
1791 struct proc *p = kn->kn_ptr.p_proc;
1793 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
1797 * signal knotes are shared with proc knotes, so we apply a mask to
1798 * the hint in order to differentiate them from process hints. This
1799 * could be avoided by using a signal-specific knote list, but probably
1800 * isn't worth the trouble.
1803 filt_signal(struct knote *kn, long hint)
1805 if (hint & NOTE_SIGNAL) {
1806 hint &= ~NOTE_SIGNAL;
1808 if (kn->kn_id == hint)
1811 return (kn->kn_data != 0);