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mtree/BSD.root.dist: Use spaces.
[dragonfly.git] / sys / kern / kern_sig.c
blob77eb6624368e014f92d0e5459f23a26c3b3940a1
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 * 3. 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 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $
36 */
37
38 #include "opt_ktrace.h"
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/sysproto.h>
44 #include <sys/signalvar.h>
45 #include <sys/resourcevar.h>
46 #include <sys/vnode.h>
47 #include <sys/event.h>
48 #include <sys/proc.h>
49 #include <sys/nlookup.h>
50 #include <sys/pioctl.h>
51 #include <sys/acct.h>
52 #include <sys/fcntl.h>
53 #include <sys/lock.h>
54 #include <sys/wait.h>
55 #include <sys/ktrace.h>
56 #include <sys/syslog.h>
57 #include <sys/stat.h>
58 #include <sys/sysent.h>
59 #include <sys/sysctl.h>
60 #include <sys/malloc.h>
61 #include <sys/interrupt.h>
62 #include <sys/unistd.h>
63 #include <sys/kern_syscall.h>
64 #include <sys/vkernel.h>
65
66 #include <sys/signal2.h>
67 #include <sys/thread2.h>
68 #include <sys/spinlock2.h>
69
70 #include <machine/cpu.h>
71 #include <machine/smp.h>
72
73 static int coredump(struct lwp *, int);
74 static char *expand_name(const char *, uid_t, pid_t);
75 static int dokillpg(int sig, int pgid, int all);
76 static int sig_ffs(sigset_t *set);
77 static int sigprop(int sig);
78 static void lwp_signotify(struct lwp *lp);
79 static void lwp_signotify_remote(void *arg);
80 static int kern_sigtimedwait(sigset_t set, siginfo_t *info,
81 struct timespec *timeout);
82 static void proc_stopwait(struct proc *p);
83
84 static int filt_sigattach(struct knote *kn);
85 static void filt_sigdetach(struct knote *kn);
86 static int filt_signal(struct knote *kn, long hint);
87
88 struct filterops sig_filtops =
89 { FILTEROP_MPSAFE, filt_sigattach, filt_sigdetach, filt_signal };
90
91 static int kern_logsigexit = 1;
92 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
93 &kern_logsigexit, 0,
94 "Log processes quitting on abnormal signals to syslog(3)");
95
96 /*
97 * Can process p send the signal sig to process q? Only processes within
98 * the current reaper or children of the current reaper can be signaled.
99 * Normally the reaper itself cannot be signalled, unless initok is set.
100 */
101 #define CANSIGNAL(q, sig, initok) \
102 ((!p_trespass(curproc->p_ucred, (q)->p_ucred) && \
103 reaper_sigtest(curproc, p, initok)) || \
104 ((sig) == SIGCONT && (q)->p_session == curproc->p_session))
105
106 /*
107 * Policy -- Can real uid ruid with ucred uc send a signal to process q?
108 */
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)
115
116 int sugid_coredump;
117 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW,
118 &sugid_coredump, 0, "Enable coredumping set user/group ID processes");
119
120 static int do_coredump = 1;
121 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
122 &do_coredump, 0, "Enable/Disable coredumps");
123
124 /*
125 * Signal properties and actions.
126 * The array below categorizes the signals and their default actions
127 * according to the following properties:
128 */
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 */
137
138
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 */
174 SA_IGNORE,
175 SA_IGNORE,
176 SA_IGNORE,
177 SA_IGNORE,
178 SA_IGNORE,
179 SA_IGNORE,
180 SA_IGNORE,
181 SA_IGNORE,
182 SA_IGNORE,
183 SA_IGNORE,
184 SA_IGNORE,
185 SA_IGNORE,
186 SA_IGNORE,
187 SA_IGNORE,
188 SA_IGNORE,
189 SA_IGNORE,
190 SA_IGNORE,
191 SA_IGNORE,
192 SA_IGNORE,
193 SA_IGNORE,
194 SA_IGNORE,
195 SA_IGNORE,
196 SA_IGNORE,
197 SA_IGNORE,
198 SA_IGNORE,
199 SA_IGNORE,
200 SA_IGNORE,
201 SA_IGNORE,
202 SA_IGNORE,
203 SA_IGNORE,
204
205 };
206
207 static __inline int
208 sigprop(int sig)
209 {
210
211 if (sig > 0 && sig < NSIG)
212 return (sigproptbl[_SIG_IDX(sig)]);
213 return (0);
214 }
215
216 static __inline int
217 sig_ffs(sigset_t *set)
218 {
219 int i;
220
221 for (i = 0; i < _SIG_WORDS; i++)
222 if (set->__bits[i])
223 return (ffs(set->__bits[i]) + (i * 32));
224 return (0);
225 }
226
227 /*
228 * No requirements.
229 */
230 int
231 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact)
232 {
233 struct thread *td = curthread;
234 struct proc *p = td->td_proc;
235 struct lwp *lp;
236 struct sigacts *ps = p->p_sigacts;
237
238 if (sig <= 0 || sig > _SIG_MAXSIG)
239 return (EINVAL);
240
241 lwkt_gettoken(&p->p_token);
242
243 if (oact) {
244 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
245 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
246 oact->sa_flags = 0;
247 if (SIGISMEMBER(ps->ps_sigonstack, sig))
248 oact->sa_flags |= SA_ONSTACK;
249 if (!SIGISMEMBER(ps->ps_sigintr, sig))
250 oact->sa_flags |= SA_RESTART;
251 if (SIGISMEMBER(ps->ps_sigreset, sig))
252 oact->sa_flags |= SA_RESETHAND;
253 if (SIGISMEMBER(ps->ps_signodefer, sig))
254 oact->sa_flags |= SA_NODEFER;
255 if (SIGISMEMBER(ps->ps_siginfo, sig))
256 oact->sa_flags |= SA_SIGINFO;
257 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP)
258 oact->sa_flags |= SA_NOCLDSTOP;
259 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT)
260 oact->sa_flags |= SA_NOCLDWAIT;
261 }
262 if (act) {
263 /*
264 * Check for invalid requests. KILL and STOP cannot be
265 * caught.
266 */
267 if (sig == SIGKILL || sig == SIGSTOP) {
268 if (act->sa_handler != SIG_DFL) {
269 lwkt_reltoken(&p->p_token);
270 return (EINVAL);
271 }
272 }
273
274 /*
275 * Change setting atomically.
276 */
277 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
278 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
279 if (act->sa_flags & SA_SIGINFO) {
280 ps->ps_sigact[_SIG_IDX(sig)] =
281 (__sighandler_t *)act->sa_sigaction;
282 SIGADDSET(ps->ps_siginfo, sig);
283 } else {
284 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
285 SIGDELSET(ps->ps_siginfo, sig);
286 }
287 if (!(act->sa_flags & SA_RESTART))
288 SIGADDSET(ps->ps_sigintr, sig);
289 else
290 SIGDELSET(ps->ps_sigintr, sig);
291 if (act->sa_flags & SA_ONSTACK)
292 SIGADDSET(ps->ps_sigonstack, sig);
293 else
294 SIGDELSET(ps->ps_sigonstack, sig);
295 if (act->sa_flags & SA_RESETHAND)
296 SIGADDSET(ps->ps_sigreset, sig);
297 else
298 SIGDELSET(ps->ps_sigreset, sig);
299 if (act->sa_flags & SA_NODEFER)
300 SIGADDSET(ps->ps_signodefer, sig);
301 else
302 SIGDELSET(ps->ps_signodefer, sig);
303 if (sig == SIGCHLD) {
304 if (act->sa_flags & SA_NOCLDSTOP)
305 p->p_sigacts->ps_flag |= PS_NOCLDSTOP;
306 else
307 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP;
308 if (act->sa_flags & SA_NOCLDWAIT) {
309 /*
310 * Paranoia: since SA_NOCLDWAIT is implemented
311 * by reparenting the dying child to PID 1 (and
312 * trust it to reap the zombie), PID 1 itself
313 * is forbidden to set SA_NOCLDWAIT.
314 */
315 if (p->p_pid == 1)
316 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
317 else
318 p->p_sigacts->ps_flag |= PS_NOCLDWAIT;
319 } else {
320 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
321 }
322 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
323 ps->ps_flag |= PS_CLDSIGIGN;
324 else
325 ps->ps_flag &= ~PS_CLDSIGIGN;
326 }
327 /*
328 * Set bit in p_sigignore for signals that are set to SIG_IGN,
329 * and for signals set to SIG_DFL where the default is to
330 * ignore. However, don't put SIGCONT in p_sigignore, as we
331 * have to restart the process.
332 *
333 * Also remove the signal from the process and lwp signal
334 * list.
335 */
336 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
337 (sigprop(sig) & SA_IGNORE &&
338 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
339 SIGDELSET_ATOMIC(p->p_siglist, sig);
340 FOREACH_LWP_IN_PROC(lp, p) {
341 spin_lock(&lp->lwp_spin);
342 SIGDELSET(lp->lwp_siglist, sig);
343 spin_unlock(&lp->lwp_spin);
344 }
345 if (sig != SIGCONT) {
346 /* easier in ksignal */
347 SIGADDSET(p->p_sigignore, sig);
348 }
349 SIGDELSET(p->p_sigcatch, sig);
350 } else {
351 SIGDELSET(p->p_sigignore, sig);
352 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
353 SIGDELSET(p->p_sigcatch, sig);
354 else
355 SIGADDSET(p->p_sigcatch, sig);
356 }
357 }
358 lwkt_reltoken(&p->p_token);
359 return (0);
360 }
361
362 int
363 sys_sigaction(struct sigaction_args *uap)
364 {
365 struct sigaction act, oact;
366 struct sigaction *actp, *oactp;
367 int error;
368
369 actp = (uap->act != NULL) ? &act : NULL;
370 oactp = (uap->oact != NULL) ? &oact : NULL;
371 if (actp) {
372 error = copyin(uap->act, actp, sizeof(act));
373 if (error)
374 return (error);
375 }
376 error = kern_sigaction(uap->sig, actp, oactp);
377 if (oactp && !error) {
378 error = copyout(oactp, uap->oact, sizeof(oact));
379 }
380 return (error);
381 }
382
383 /*
384 * Initialize signal state for process 0;
385 * set to ignore signals that are ignored by default.
386 */
387 void
388 siginit(struct proc *p)
389 {
390 int i;
391
392 for (i = 1; i <= NSIG; i++)
393 if (sigprop(i) & SA_IGNORE && i != SIGCONT)
394 SIGADDSET(p->p_sigignore, i);
395 }
396
397 /*
398 * Reset signals for an exec of the specified process.
399 */
400 void
401 execsigs(struct proc *p)
402 {
403 struct sigacts *ps = p->p_sigacts;
404 struct lwp *lp;
405 int sig;
406
407 lp = ONLY_LWP_IN_PROC(p);
408
409 /*
410 * Reset caught signals. Held signals remain held
411 * through p_sigmask (unless they were caught,
412 * and are now ignored by default).
413 */
414 while (SIGNOTEMPTY(p->p_sigcatch)) {
415 sig = sig_ffs(&p->p_sigcatch);
416 SIGDELSET(p->p_sigcatch, sig);
417 if (sigprop(sig) & SA_IGNORE) {
418 if (sig != SIGCONT)
419 SIGADDSET(p->p_sigignore, sig);
420 SIGDELSET_ATOMIC(p->p_siglist, sig);
421 /* don't need spinlock */
422 SIGDELSET(lp->lwp_siglist, sig);
423 }
424 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
425 }
426
427 /*
428 * Reset stack state to the user stack.
429 * Clear set of signals caught on the signal stack.
430 */
431 lp->lwp_sigstk.ss_flags = SS_DISABLE;
432 lp->lwp_sigstk.ss_size = 0;
433 lp->lwp_sigstk.ss_sp = NULL;
434 lp->lwp_flags &= ~LWP_ALTSTACK;
435 /*
436 * Reset no zombies if child dies flag as Solaris does.
437 */
438 p->p_sigacts->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
439 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
440 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
441 }
442
443 /*
444 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc
445 *
446 * Manipulate signal mask. This routine is MP SAFE *ONLY* if
447 * p == curproc.
448 */
449 int
450 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset)
451 {
452 struct thread *td = curthread;
453 struct lwp *lp = td->td_lwp;
454 struct proc *p = td->td_proc;
455 int error;
456
457 lwkt_gettoken(&p->p_token);
458
459 if (oset != NULL)
460 *oset = lp->lwp_sigmask;
461
462 error = 0;
463 if (set != NULL) {
464 switch (how) {
465 case SIG_BLOCK:
466 SIG_CANTMASK(*set);
467 SIGSETOR(lp->lwp_sigmask, *set);
468 break;
469 case SIG_UNBLOCK:
470 SIGSETNAND(lp->lwp_sigmask, *set);
471 break;
472 case SIG_SETMASK:
473 SIG_CANTMASK(*set);
474 lp->lwp_sigmask = *set;
475 break;
476 default:
477 error = EINVAL;
478 break;
479 }
480 }
481
482 lwkt_reltoken(&p->p_token);
483
484 return (error);
485 }
486
487 /*
488 * sigprocmask()
489 *
490 * MPSAFE
491 */
492 int
493 sys_sigprocmask(struct sigprocmask_args *uap)
494 {
495 sigset_t set, oset;
496 sigset_t *setp, *osetp;
497 int error;
498
499 setp = (uap->set != NULL) ? &set : NULL;
500 osetp = (uap->oset != NULL) ? &oset : NULL;
501 if (setp) {
502 error = copyin(uap->set, setp, sizeof(set));
503 if (error)
504 return (error);
505 }
506 error = kern_sigprocmask(uap->how, setp, osetp);
507 if (osetp && !error) {
508 error = copyout(osetp, uap->oset, sizeof(oset));
509 }
510 return (error);
511 }
512
513 /*
514 * MPSAFE
515 */
516 int
517 kern_sigpending(struct __sigset *set)
518 {
519 struct lwp *lp = curthread->td_lwp;
520
521 *set = lwp_sigpend(lp);
522
523 return (0);
524 }
525
526 /*
527 * MPSAFE
528 */
529 int
530 sys_sigpending(struct sigpending_args *uap)
531 {
532 sigset_t set;
533 int error;
534
535 error = kern_sigpending(&set);
536
537 if (error == 0)
538 error = copyout(&set, uap->set, sizeof(set));
539 return (error);
540 }
541
542 /*
543 * Suspend process until signal, providing mask to be set
544 * in the meantime.
545 *
546 * MPSAFE
547 */
548 int
549 kern_sigsuspend(struct __sigset *set)
550 {
551 struct thread *td = curthread;
552 struct lwp *lp = td->td_lwp;
553 struct proc *p = td->td_proc;
554 struct sigacts *ps = p->p_sigacts;
555
556 /*
557 * When returning from sigsuspend, we want
558 * the old mask to be restored after the
559 * signal handler has finished. Thus, we
560 * save it here and mark the sigacts structure
561 * to indicate this.
562 */
563 lp->lwp_oldsigmask = lp->lwp_sigmask;
564 lp->lwp_flags |= LWP_OLDMASK;
565
566 SIG_CANTMASK(*set);
567 lp->lwp_sigmask = *set;
568 while (tsleep(ps, PCATCH, "pause", 0) == 0)
569 /* void */;
570 /* always return EINTR rather than ERESTART... */
571 return (EINTR);
572 }
573
574 /*
575 * Note nonstandard calling convention: libc stub passes mask, not
576 * pointer, to save a copyin.
577 *
578 * MPSAFE
579 */
580 int
581 sys_sigsuspend(struct sigsuspend_args *uap)
582 {
583 sigset_t mask;
584 int error;
585
586 error = copyin(uap->sigmask, &mask, sizeof(mask));
587 if (error)
588 return (error);
589
590 error = kern_sigsuspend(&mask);
591
592 return (error);
593 }
594
595 /*
596 * MPSAFE
597 */
598 int
599 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss)
600 {
601 struct thread *td = curthread;
602 struct lwp *lp = td->td_lwp;
603 struct proc *p = td->td_proc;
604
605 if ((lp->lwp_flags & LWP_ALTSTACK) == 0)
606 lp->lwp_sigstk.ss_flags |= SS_DISABLE;
607
608 if (oss)
609 *oss = lp->lwp_sigstk;
610
611 if (ss) {
612 if (ss->ss_flags & ~SS_DISABLE)
613 return (EINVAL);
614 if (ss->ss_flags & SS_DISABLE) {
615 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK)
616 return (EPERM);
617 lp->lwp_flags &= ~LWP_ALTSTACK;
618 lp->lwp_sigstk.ss_flags = ss->ss_flags;
619 } else {
620 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
621 return (ENOMEM);
622 lp->lwp_flags |= LWP_ALTSTACK;
623 lp->lwp_sigstk = *ss;
624 }
625 }
626
627 return (0);
628 }
629
630 /*
631 * MPSAFE
632 */
633 int
634 sys_sigaltstack(struct sigaltstack_args *uap)
635 {
636 stack_t ss, oss;
637 int error;
638
639 if (uap->ss) {
640 error = copyin(uap->ss, &ss, sizeof(ss));
641 if (error)
642 return (error);
643 }
644
645 error = kern_sigaltstack(uap->ss ? &ss : NULL, uap->oss ? &oss : NULL);
646
647 if (error == 0 && uap->oss)
648 error = copyout(&oss, uap->oss, sizeof(*uap->oss));
649 return (error);
650 }
651
652 /*
653 * Common code for kill process group/broadcast kill.
654 * cp is calling process.
655 */
656 struct killpg_info {
657 int nfound;
658 int sig;
659 };
660
661 static int killpg_all_callback(struct proc *p, void *data);
662
663 static int
664 dokillpg(int sig, int pgid, int all)
665 {
666 struct killpg_info info;
667 struct proc *cp = curproc;
668 struct proc *p;
669 struct pgrp *pgrp;
670
671 info.nfound = 0;
672 info.sig = sig;
673
674 if (all) {
675 /*
676 * broadcast
677 */
678 allproc_scan(killpg_all_callback, &info, 0);
679 } else {
680 if (pgid == 0) {
681 /*
682 * zero pgid means send to my process group.
683 */
684 pgrp = cp->p_pgrp;
685 pgref(pgrp);
686 } else {
687 pgrp = pgfind(pgid);
688 if (pgrp == NULL)
689 return (ESRCH);
690 }
691
692 /*
693 * Must interlock all signals against fork
694 */
695 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
696 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
697 if (p->p_pid <= 1 ||
698 p->p_stat == SZOMB ||
699 (p->p_flags & P_SYSTEM) ||
700 !CANSIGNAL(p, sig, 0)) {
701 continue;
702 }
703 ++info.nfound;
704 if (sig)
705 ksignal(p, sig);
706 }
707 lockmgr(&pgrp->pg_lock, LK_RELEASE);
708 pgrel(pgrp);
709 }
710 return (info.nfound ? 0 : ESRCH);
711 }
712
713 static int
714 killpg_all_callback(struct proc *p, void *data)
715 {
716 struct killpg_info *info = data;
717
718 if (p->p_pid <= 1 || (p->p_flags & P_SYSTEM) ||
719 p == curproc || !CANSIGNAL(p, info->sig, 0)) {
720 return (0);
721 }
722 ++info->nfound;
723 if (info->sig)
724 ksignal(p, info->sig);
725 return(0);
726 }
727
728 /*
729 * Send a general signal to a process or LWPs within that process.
730 *
731 * Note that new signals cannot be sent if a process is exiting or already
732 * a zombie, but we return success anyway as userland is likely to not handle
733 * the race properly.
734 *
735 * No requirements.
736 */
737 int
738 kern_kill(int sig, pid_t pid, lwpid_t tid)
739 {
740 int t;
741
742 if ((u_int)sig > _SIG_MAXSIG)
743 return (EINVAL);
744
745 if (pid > 0) {
746 struct proc *p;
747 struct lwp *lp = NULL;
748
749 /*
750 * Send a signal to a single process. If the kill() is
751 * racing an exiting process which has not yet been reaped
752 * act as though the signal was delivered successfully but
753 * don't actually try to deliver the signal.
754 */
755 if ((p = pfind(pid)) == NULL) {
756 if ((p = zpfind(pid)) == NULL)
757 return (ESRCH);
758 PRELE(p);
759 return (0);
760 }
761 if (p != curproc) {
762 lwkt_gettoken_shared(&p->p_token);
763 if (!CANSIGNAL(p, sig, 1)) {
764 lwkt_reltoken(&p->p_token);
765 PRELE(p);
766 return (EPERM);
767 }
768 lwkt_reltoken(&p->p_token);
769 }
770
771 /*
772 * NOP if the process is exiting. Note that lwpsignal() is
773 * called directly with P_WEXIT set to kill individual LWPs
774 * during exit, which is allowed.
775 */
776 if (p->p_flags & P_WEXIT) {
777 PRELE(p);
778 return (0);
779 }
780 if (tid != -1) {
781 lwkt_gettoken_shared(&p->p_token);
782 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid);
783 if (lp == NULL) {
784 lwkt_reltoken(&p->p_token);
785 PRELE(p);
786 return (ESRCH);
787 }
788 LWPHOLD(lp);
789 lwkt_reltoken(&p->p_token);
790 }
791 if (sig)
792 lwpsignal(p, lp, sig);
793 if (lp)
794 LWPRELE(lp);
795 PRELE(p);
796
797 return (0);
798 }
799
800 /*
801 * If we come here, pid is a special broadcast pid.
802 * This doesn't mix with a tid.
803 */
804 if (tid != -1)
805 return (EINVAL);
806
807 switch (pid) {
808 case -1: /* broadcast signal */
809 t = (dokillpg(sig, 0, 1));
810 break;
811 case 0: /* signal own process group */
812 t = (dokillpg(sig, 0, 0));
813 break;
814 default: /* negative explicit process group */
815 t = (dokillpg(sig, -pid, 0));
816 break;
817 }
818 return t;
819 }
820
821 int
822 sys_kill(struct kill_args *uap)
823 {
824 int error;
825
826 error = kern_kill(uap->signum, uap->pid, -1);
827 return (error);
828 }
829
830 int
831 sys_lwp_kill(struct lwp_kill_args *uap)
832 {
833 int error;
834 pid_t pid = uap->pid;
835
836 /*
837 * A tid is mandatory for lwp_kill(), otherwise
838 * you could simply use kill().
839 */
840 if (uap->tid == -1)
841 return (EINVAL);
842
843 /*
844 * To save on a getpid() function call for intra-process
845 * signals, pid == -1 means current process.
846 */
847 if (pid == -1)
848 pid = curproc->p_pid;
849
850 error = kern_kill(uap->signum, pid, uap->tid);
851 return (error);
852 }
853
854 /*
855 * Send a signal to a process group.
856 */
857 void
858 gsignal(int pgid, int sig)
859 {
860 struct pgrp *pgrp;
861
862 if (pgid && (pgrp = pgfind(pgid)))
863 pgsignal(pgrp, sig, 0);
864 }
865
866 /*
867 * Send a signal to a process group. If checktty is 1,
868 * limit to members which have a controlling terminal.
869 *
870 * pg_lock interlocks against a fork that might be in progress, to
871 * ensure that the new child process picks up the signal.
872 */
873 void
874 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
875 {
876 struct proc *p;
877
878 /*
879 * Must interlock all signals against fork
880 */
881 if (pgrp) {
882 pgref(pgrp);
883 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
884 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
885 if (checkctty == 0 || p->p_flags & P_CONTROLT)
886 ksignal(p, sig);
887 }
888 lockmgr(&pgrp->pg_lock, LK_RELEASE);
889 pgrel(pgrp);
890 }
891 }
892
893 /*
894 * Send a signal caused by a trap to the current lwp. If it will be caught
895 * immediately, deliver it with correct code. Otherwise, post it normally.
896 *
897 * These signals may ONLY be delivered to the specified lwp and may never
898 * be delivered to the process generically.
899 */
900 void
901 trapsignal(struct lwp *lp, int sig, u_long code)
902 {
903 struct proc *p = lp->lwp_proc;
904 struct sigacts *ps = p->p_sigacts;
905
906 /*
907 * If we are a virtual kernel running an emulated user process
908 * context, switch back to the virtual kernel context before
909 * trying to post the signal.
910 */
911 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
912 struct trapframe *tf = lp->lwp_md.md_regs;
913 tf->tf_trapno = 0;
914 vkernel_trap(lp, tf);
915 }
916
917 if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
918 !SIGISMEMBER(lp->lwp_sigmask, sig)) {
919 lp->lwp_ru.ru_nsignals++;
920 #ifdef KTRACE
921 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
922 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)],
923 &lp->lwp_sigmask, code);
924 #endif
925 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
926 &lp->lwp_sigmask, code);
927 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
928 if (!SIGISMEMBER(ps->ps_signodefer, sig))
929 SIGADDSET(lp->lwp_sigmask, sig);
930 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
931 /*
932 * See kern_sigaction() for origin of this code.
933 */
934 SIGDELSET(p->p_sigcatch, sig);
935 if (sig != SIGCONT &&
936 sigprop(sig) & SA_IGNORE)
937 SIGADDSET(p->p_sigignore, sig);
938 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
939 }
940 } else {
941 lp->lwp_code = code; /* XXX for core dump/debugger */
942 lp->lwp_sig = sig; /* XXX to verify code */
943 lwpsignal(p, lp, sig);
944 }
945 }
946
947 /*
948 * Find a suitable lwp to deliver the signal to. Returns NULL if all
949 * lwps hold the signal blocked.
950 *
951 * Caller must hold p->p_token.
952 *
953 * Returns a lp or NULL. If non-NULL the lp is held and its token is
954 * acquired.
955 */
956 static struct lwp *
957 find_lwp_for_signal(struct proc *p, int sig)
958 {
959 struct lwp *lp;
960 struct lwp *run, *sleep, *stop;
961
962 /*
963 * If the running/preempted thread belongs to the proc to which
964 * the signal is being delivered and this thread does not block
965 * the signal, then we can avoid a context switch by delivering
966 * the signal to this thread, because it will return to userland
967 * soon anyways.
968 */
969 lp = lwkt_preempted_proc();
970 if (lp != NULL && lp->lwp_proc == p) {
971 LWPHOLD(lp);
972 lwkt_gettoken(&lp->lwp_token);
973 if (!SIGISMEMBER(lp->lwp_sigmask, sig)) {
974 /* return w/ token held */
975 return (lp);
976 }
977 lwkt_reltoken(&lp->lwp_token);
978 LWPRELE(lp);
979 }
980
981 run = sleep = stop = NULL;
982 FOREACH_LWP_IN_PROC(lp, p) {
983 /*
984 * If the signal is being blocked by the lwp, then this
985 * lwp is not eligible for receiving the signal.
986 */
987 LWPHOLD(lp);
988 lwkt_gettoken(&lp->lwp_token);
989
990 if (SIGISMEMBER(lp->lwp_sigmask, sig)) {
991 lwkt_reltoken(&lp->lwp_token);
992 LWPRELE(lp);
993 continue;
994 }
995
996 switch (lp->lwp_stat) {
997 case LSRUN:
998 if (sleep) {
999 lwkt_token_swap();
1000 lwkt_reltoken(&sleep->lwp_token);
1001 LWPRELE(sleep);
1002 sleep = NULL;
1003 run = lp;
1004 } else if (stop) {
1005 lwkt_token_swap();
1006 lwkt_reltoken(&stop->lwp_token);
1007 LWPRELE(stop);
1008 stop = NULL;
1009 run = lp;
1010 } else {
1011 run = lp;
1012 }
1013 break;
1014 case LSSLEEP:
1015 if (lp->lwp_flags & LWP_SINTR) {
1016 if (sleep) {
1017 lwkt_reltoken(&lp->lwp_token);
1018 LWPRELE(lp);
1019 } else if (stop) {
1020 lwkt_token_swap();
1021 lwkt_reltoken(&stop->lwp_token);
1022 LWPRELE(stop);
1023 stop = NULL;
1024 sleep = lp;
1025 } else {
1026 sleep = lp;
1027 }
1028 } else {
1029 lwkt_reltoken(&lp->lwp_token);
1030 LWPRELE(lp);
1031 }
1032 break;
1033 case LSSTOP:
1034 if (sleep) {
1035 lwkt_reltoken(&lp->lwp_token);
1036 LWPRELE(lp);
1037 } else if (stop) {
1038 lwkt_reltoken(&lp->lwp_token);
1039 LWPRELE(lp);
1040 } else {
1041 stop = lp;
1042 }
1043 break;
1044 }
1045 if (run)
1046 break;
1047 }
1048
1049 if (run != NULL)
1050 return (run);
1051 else if (sleep != NULL)
1052 return (sleep);
1053 else
1054 return (stop);
1055 }
1056
1057 /*
1058 * Send the signal to the process. If the signal has an action, the action
1059 * is usually performed by the target process rather than the caller; we add
1060 * the signal to the set of pending signals for the process.
1061 *
1062 * Exceptions:
1063 * o When a stop signal is sent to a sleeping process that takes the
1064 * default action, the process is stopped without awakening it.
1065 * o SIGCONT restarts stopped processes (or puts them back to sleep)
1066 * regardless of the signal action (eg, blocked or ignored).
1067 *
1068 * Other ignored signals are discarded immediately.
1069 *
1070 * If the caller wishes to call this function from a hard code section the
1071 * caller must already hold p->p_token (see kern_clock.c).
1072 *
1073 * No requirements.
1074 */
1075 void
1076 ksignal(struct proc *p, int sig)
1077 {
1078 lwpsignal(p, NULL, sig);
1079 }
1080
1081 /*
1082 * The core for ksignal. lp may be NULL, then a suitable thread
1083 * will be chosen. If not, lp MUST be a member of p.
1084 *
1085 * If the caller wishes to call this function from a hard code section the
1086 * caller must already hold p->p_token.
1087 *
1088 * No requirements.
1089 */
1090 void
1091 lwpsignal(struct proc *p, struct lwp *lp, int sig)
1092 {
1093 struct proc *q;
1094 sig_t action;
1095 int prop;
1096
1097 if (sig > _SIG_MAXSIG || sig <= 0) {
1098 kprintf("lwpsignal: signal %d\n", sig);
1099 panic("lwpsignal signal number");
1100 }
1101
1102 KKASSERT(lp == NULL || lp->lwp_proc == p);
1103
1104 /*
1105 * We don't want to race... well, all sorts of things. Get appropriate
1106 * tokens.
1107 *
1108 * Don't try to deliver a generic signal to an exiting process,
1109 * the signal structures could be in flux. We check the LWP later
1110 * on.
1111 */
1112 PHOLD(p);
1113 if (lp) {
1114 LWPHOLD(lp);
1115 lwkt_gettoken(&lp->lwp_token);
1116 } else {
1117 lwkt_gettoken(&p->p_token);
1118 if (p->p_flags & P_WEXIT)
1119 goto out;
1120 }
1121
1122 prop = sigprop(sig);
1123
1124 /*
1125 * If proc is traced, always give parent a chance;
1126 * if signal event is tracked by procfs, give *that*
1127 * a chance, as well.
1128 */
1129 if ((p->p_flags & P_TRACED) || (p->p_stops & S_SIG)) {
1130 action = SIG_DFL;
1131 } else {
1132 /*
1133 * Do not try to deliver signals to an exiting lwp other
1134 * than SIGKILL. Note that we must still deliver the signal
1135 * if P_WEXIT is set in the process flags.
1136 */
1137 if (lp && (lp->lwp_mpflags & LWP_MP_WEXIT) && sig != SIGKILL) {
1138 lwkt_reltoken(&lp->lwp_token);
1139 LWPRELE(lp);
1140 PRELE(p);
1141 return;
1142 }
1143
1144 /*
1145 * If the signal is being ignored, then we forget about
1146 * it immediately. NOTE: We don't set SIGCONT in p_sigignore,
1147 * and if it is set to SIG_IGN, action will be SIG_DFL here.
1148 */
1149 if (SIGISMEMBER(p->p_sigignore, sig)) {
1150 /*
1151 * Even if a signal is set SIG_IGN, it may still be
1152 * lurking in a kqueue.
1153 */
1154 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
1155 if (lp) {
1156 lwkt_reltoken(&lp->lwp_token);
1157 LWPRELE(lp);
1158 } else {
1159 lwkt_reltoken(&p->p_token);
1160 }
1161 PRELE(p);
1162 return;
1163 }
1164 if (SIGISMEMBER(p->p_sigcatch, sig))
1165 action = SIG_CATCH;
1166 else
1167 action = SIG_DFL;
1168 }
1169
1170 /*
1171 * If continuing, clear any pending STOP signals for the whole
1172 * process.
1173 */
1174 if (prop & SA_CONT) {
1175 lwkt_gettoken(&p->p_token);
1176 SIG_STOPSIGMASK_ATOMIC(p->p_siglist);
1177 lwkt_reltoken(&p->p_token);
1178 }
1179
1180 if (prop & SA_STOP) {
1181 /*
1182 * If sending a tty stop signal to a member of an orphaned
1183 * process group, discard the signal here if the action
1184 * is default; don't stop the process below if sleeping,
1185 * and don't clear any pending SIGCONT.
1186 */
1187 if ((prop & SA_TTYSTOP) && p->p_pgrp->pg_jobc == 0 &&
1188 action == SIG_DFL) {
1189 if (lp) {
1190 lwkt_reltoken(&lp->lwp_token);
1191 LWPRELE(lp);
1192 } else {
1193 lwkt_reltoken(&p->p_token);
1194 }
1195 PRELE(p);
1196 return;
1197 }
1198 lwkt_gettoken(&p->p_token);
1199 SIG_CONTSIGMASK_ATOMIC(p->p_siglist);
1200 p->p_flags &= ~P_CONTINUED;
1201 lwkt_reltoken(&p->p_token);
1202 }
1203
1204 if (p->p_stat == SSTOP) {
1205 /*
1206 * Nobody can handle this signal, add it to the lwp or
1207 * process pending list
1208 */
1209 lwkt_gettoken(&p->p_token);
1210 if (p->p_stat != SSTOP) {
1211 lwkt_reltoken(&p->p_token);
1212 goto not_stopped;
1213 }
1214 if (lp) {
1215 spin_lock(&lp->lwp_spin);
1216 SIGADDSET(lp->lwp_siglist, sig);
1217 spin_unlock(&lp->lwp_spin);
1218 } else {
1219 SIGADDSET_ATOMIC(p->p_siglist, sig);
1220 }
1221
1222 /*
1223 * If the process is stopped and is being traced, then no
1224 * further action is necessary.
1225 */
1226 if (p->p_flags & P_TRACED) {
1227 lwkt_reltoken(&p->p_token);
1228 goto out;
1229 }
1230
1231 /*
1232 * If the process is stopped and receives a KILL signal,
1233 * make the process runnable.
1234 */
1235 if (sig == SIGKILL) {
1236 proc_unstop(p, SSTOP);
1237 lwkt_reltoken(&p->p_token);
1238 goto active_process;
1239 }
1240
1241 /*
1242 * If the process is stopped and receives a CONT signal,
1243 * then try to make the process runnable again.
1244 */
1245 if (prop & SA_CONT) {
1246 /*
1247 * If SIGCONT is default (or ignored), we continue the
1248 * process but don't leave the signal in p_siglist, as
1249 * it has no further action. If SIGCONT is held, we
1250 * continue the process and leave the signal in
1251 * p_siglist. If the process catches SIGCONT, let it
1252 * handle the signal itself.
1253 *
1254 * XXX what if the signal is being held blocked?
1255 *
1256 * Token required to interlock kern_wait().
1257 * Reparenting can also cause a race so we have to
1258 * hold (q).
1259 */
1260 q = p->p_pptr;
1261 PHOLD(q);
1262 lwkt_gettoken(&q->p_token);
1263 p->p_flags |= P_CONTINUED;
1264 wakeup(q);
1265 if (action == SIG_DFL)
1266 SIGDELSET_ATOMIC(p->p_siglist, sig);
1267 proc_unstop(p, SSTOP);
1268 lwkt_reltoken(&q->p_token);
1269 PRELE(q);
1270 lwkt_reltoken(&p->p_token);
1271 if (action == SIG_CATCH)
1272 goto active_process;
1273 goto out;
1274 }
1275
1276 /*
1277 * If the process is stopped and receives another STOP
1278 * signal, we do not need to stop it again. If we did
1279 * the shell could get confused.
1280 *
1281 * However, if the current/preempted lwp is part of the
1282 * process receiving the signal, we need to keep it,
1283 * so that this lwp can stop in issignal() later, as
1284 * we don't want to wait until it reaches userret!
1285 */
1286 if (prop & SA_STOP) {
1287 if (lwkt_preempted_proc() == NULL ||
1288 lwkt_preempted_proc()->lwp_proc != p) {
1289 SIGDELSET_ATOMIC(p->p_siglist, sig);
1290 }
1291 }
1292
1293 /*
1294 * Otherwise the process is stopped and it received some
1295 * signal, which does not change its stopped state. When
1296 * the process is continued a wakeup(p) will be issued which
1297 * will wakeup any threads sleeping in tstop().
1298 */
1299 lwkt_reltoken(&p->p_token);
1300 goto out;
1301 /* NOTREACHED */
1302 }
1303 not_stopped:
1304 ;
1305 /* else not stopped */
1306 active_process:
1307
1308 /*
1309 * Never deliver a lwp-specific signal to a random lwp.
1310 */
1311 if (lp == NULL) {
1312 /* NOTE: returns lp w/ token held */
1313 lp = find_lwp_for_signal(p, sig);
1314 if (lp) {
1315 if (SIGISMEMBER(lp->lwp_sigmask, sig)) {
1316 lwkt_reltoken(&lp->lwp_token);
1317 LWPRELE(lp);
1318 lp = NULL;
1319 /* maintain proc token */
1320 } else {
1321 lwkt_token_swap();
1322 lwkt_reltoken(&p->p_token);
1323 /* maintain lp token */
1324 }
1325 }
1326 }
1327
1328 /*
1329 * Deliver to the process generically if (1) the signal is being
1330 * sent to any thread or (2) we could not find a thread to deliver
1331 * it to.
1332 */
1333 if (lp == NULL) {
1334 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
1335 SIGADDSET_ATOMIC(p->p_siglist, sig);
1336 goto out;
1337 }
1338
1339 /*
1340 * Deliver to a specific LWP whether it masks it or not. It will
1341 * not be dispatched if masked but we must still deliver it.
1342 */
1343 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
1344 (p->p_flags & P_TRACED) == 0) {
1345 lwkt_gettoken(&p->p_token);
1346 p->p_nice = NZERO;
1347 lwkt_reltoken(&p->p_token);
1348 }
1349
1350 /*
1351 * If the process receives a STOP signal which indeed needs to
1352 * stop the process, do so. If the process chose to catch the
1353 * signal, it will be treated like any other signal.
1354 */
1355 if ((prop & SA_STOP) && action == SIG_DFL) {
1356 /*
1357 * If a child holding parent blocked, stopping
1358 * could cause deadlock. Take no action at this
1359 * time.
1360 */
1361 lwkt_gettoken(&p->p_token);
1362 if (p->p_flags & P_PPWAIT) {
1363 SIGADDSET_ATOMIC(p->p_siglist, sig);
1364 lwkt_reltoken(&p->p_token);
1365 goto out;
1366 }
1367
1368 /*
1369 * Do not actually try to manipulate the process, but simply
1370 * stop it. Lwps will stop as soon as they safely can.
1371 *
1372 * Ignore stop if the process is exiting.
1373 */
1374 if ((p->p_flags & P_WEXIT) == 0) {
1375 p->p_xstat = sig;
1376 proc_stop(p, SSTOP);
1377 }
1378 lwkt_reltoken(&p->p_token);
1379 goto out;
1380 }
1381
1382 /*
1383 * If it is a CONT signal with default action, just ignore it.
1384 */
1385 if ((prop & SA_CONT) && action == SIG_DFL)
1386 goto out;
1387
1388 /*
1389 * Mark signal pending at this specific thread.
1390 */
1391 spin_lock(&lp->lwp_spin);
1392 SIGADDSET(lp->lwp_siglist, sig);
1393 spin_unlock(&lp->lwp_spin);
1394
1395 lwp_signotify(lp);
1396
1397 out:
1398 if (lp) {
1399 lwkt_reltoken(&lp->lwp_token);
1400 LWPRELE(lp);
1401 } else {
1402 lwkt_reltoken(&p->p_token);
1403 }
1404 PRELE(p);
1405 }
1406
1407 /*
1408 * Notify the LWP that a signal has arrived. The LWP does not have to be
1409 * sleeping on the current cpu.
1410 *
1411 * p->p_token and lp->lwp_token must be held on call.
1412 *
1413 * We can only safely schedule the thread on its current cpu and only if
1414 * one of the SINTR flags is set. If an SINTR flag is set AND we are on
1415 * the correct cpu we are properly interlocked, otherwise we could be
1416 * racing other thread transition states (or the lwp is on the user scheduler
1417 * runq but not scheduled) and must not do anything.
1418 *
1419 * Since we hold the lwp token we know the lwp cannot be ripped out from
1420 * under us so we can safely hold it to prevent it from being ripped out
1421 * from under us if we are forced to IPI another cpu to make the local
1422 * checks there.
1423 *
1424 * Adjustment of lp->lwp_stat can only occur when we hold the lwp_token,
1425 * which we won't in an IPI so any fixups have to be done here, effectively
1426 * replicating part of what setrunnable() does.
1427 */
1428 static void
1429 lwp_signotify(struct lwp *lp)
1430 {
1431 thread_t dtd;
1432
1433 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_token);
1434 dtd = lp->lwp_thread;
1435
1436 crit_enter();
1437 if (lp == lwkt_preempted_proc()) {
1438 /*
1439 * lwp is on the current cpu AND it is currently running
1440 * (we preempted it).
1441 */
1442 signotify();
1443 } else if (lp->lwp_flags & LWP_SINTR) {
1444 /*
1445 * lwp is sitting in tsleep() with PCATCH set
1446 */
1447 if (dtd->td_gd == mycpu) {
1448 setrunnable(lp);
1449 } else {
1450 /*
1451 * We can only adjust lwp_stat while we hold the
1452 * lwp_token, and we won't in the IPI function.
1453 */
1454 LWPHOLD(lp);
1455 if (lp->lwp_stat == LSSTOP)
1456 lp->lwp_stat = LSSLEEP;
1457 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1458 }
1459 } else if (dtd->td_flags & TDF_SINTR) {
1460 /*
1461 * lwp is sitting in lwkt_sleep() with PCATCH set.
1462 */
1463 if (dtd->td_gd == mycpu) {
1464 setrunnable(lp);
1465 } else {
1466 /*
1467 * We can only adjust lwp_stat while we hold the
1468 * lwp_token, and we won't in the IPI function.
1469 */
1470 LWPHOLD(lp);
1471 if (lp->lwp_stat == LSSTOP)
1472 lp->lwp_stat = LSSLEEP;
1473 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1474 }
1475 } else {
1476 /*
1477 * Otherwise the lwp is either in some uninterruptible state
1478 * or it is on the userland scheduler's runqueue waiting to
1479 * be scheduled to a cpu, or it is running in userland. We
1480 * generally want to send an IPI so a running target gets the
1481 * signal ASAP, otherwise a scheduler-tick worth of latency
1482 * will occur.
1483 *
1484 * Issue an IPI to the remote cpu to knock it into the kernel,
1485 * remote cpu will issue the cpu-local signotify() if the IPI
1486 * preempts the desired thread.
1487 */
1488 if (dtd->td_gd != mycpu) {
1489 LWPHOLD(lp);
1490 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1491 }
1492 }
1493 crit_exit();
1494 }
1495
1496 /*
1497 * This function is called via an IPI so we cannot call setrunnable() here
1498 * (because while we hold the lp we don't own its token, and can't get it
1499 * from an IPI).
1500 *
1501 * We are interlocked by virtue of being on the same cpu as the target. If
1502 * we still are and LWP_SINTR or TDF_SINTR is set we can safely schedule
1503 * the target thread.
1504 */
1505 static void
1506 lwp_signotify_remote(void *arg)
1507 {
1508 struct lwp *lp = arg;
1509 thread_t td = lp->lwp_thread;
1510
1511 if (lp == lwkt_preempted_proc()) {
1512 signotify();
1513 LWPRELE(lp);
1514 } else if (td->td_gd == mycpu) {
1515 if ((lp->lwp_flags & LWP_SINTR) ||
1516 (td->td_flags & TDF_SINTR)) {
1517 lwkt_schedule(td);
1518 }
1519 LWPRELE(lp);
1520 } else {
1521 lwkt_send_ipiq(td->td_gd, lwp_signotify_remote, lp);
1522 /* LWPHOLD() is forwarded to the target cpu */
1523 }
1524 }
1525
1526 /*
1527 * Caller must hold p->p_token
1528 */
1529 void
1530 proc_stop(struct proc *p, int sig)
1531 {
1532 struct proc *q;
1533 struct lwp *lp;
1534
1535 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
1536
1537 /*
1538 * If somebody raced us, be happy with it. SCORE overrides SSTOP.
1539 */
1540 if (sig == SCORE) {
1541 if (p->p_stat == SCORE || p->p_stat == SZOMB)
1542 return;
1543 } else {
1544 if (p->p_stat == SSTOP || p->p_stat == SCORE ||
1545 p->p_stat == SZOMB) {
1546 return;
1547 }
1548 }
1549 p->p_stat = sig;
1550
1551 FOREACH_LWP_IN_PROC(lp, p) {
1552 LWPHOLD(lp);
1553 lwkt_gettoken(&lp->lwp_token);
1554
1555 switch (lp->lwp_stat) {
1556 case LSSTOP:
1557 /*
1558 * Do nothing, we are already counted in
1559 * p_nstopped.
1560 */
1561 break;
1562
1563 case LSSLEEP:
1564 /*
1565 * We're sleeping, but we will stop before
1566 * returning to userspace, so count us
1567 * as stopped as well. We set LWP_MP_WSTOP
1568 * to signal the lwp that it should not
1569 * increase p_nstopped when reaching tstop().
1570 *
1571 * LWP_MP_WSTOP is protected by lp->lwp_token.
1572 */
1573 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) {
1574 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP);
1575 ++p->p_nstopped;
1576 }
1577 break;
1578
1579 case LSRUN:
1580 /*
1581 * We might notify ourself, but that's not
1582 * a problem.
1583 */
1584 lwp_signotify(lp);
1585 break;
1586 }
1587 lwkt_reltoken(&lp->lwp_token);
1588 LWPRELE(lp);
1589 }
1590
1591 if (p->p_nstopped == p->p_nthreads) {
1592 /*
1593 * Token required to interlock kern_wait(). Reparenting can
1594 * also cause a race so we have to hold (q).
1595 */
1596 q = p->p_pptr;
1597 PHOLD(q);
1598 lwkt_gettoken(&q->p_token);
1599 p->p_flags &= ~P_WAITED;
1600 wakeup(q);
1601 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1602 ksignal(p->p_pptr, SIGCHLD);
1603 lwkt_reltoken(&q->p_token);
1604 PRELE(q);
1605 }
1606 }
1607
1608 /*
1609 * Caller must hold p_token
1610 */
1611 void
1612 proc_unstop(struct proc *p, int sig)
1613 {
1614 struct lwp *lp;
1615
1616 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
1617
1618 if (p->p_stat != sig)
1619 return;
1620
1621 p->p_stat = SACTIVE;
1622
1623 FOREACH_LWP_IN_PROC(lp, p) {
1624 LWPHOLD(lp);
1625 lwkt_gettoken(&lp->lwp_token);
1626
1627 switch (lp->lwp_stat) {
1628 case LSRUN:
1629 /*
1630 * Uh? Not stopped? Well, I guess that's okay.
1631 */
1632 if (bootverbose)
1633 kprintf("proc_unstop: lwp %d/%d not sleeping\n",
1634 p->p_pid, lp->lwp_tid);
1635 break;
1636
1637 case LSSLEEP:
1638 /*
1639 * Still sleeping. Don't bother waking it up.
1640 * However, if this thread was counted as
1641 * stopped, undo this.
1642 *
1643 * Nevertheless we call setrunnable() so that it
1644 * will wake up in case a signal or timeout arrived
1645 * in the meantime.
1646 *
1647 * LWP_MP_WSTOP is protected by lp->lwp_token.
1648 */
1649 if (lp->lwp_mpflags & LWP_MP_WSTOP) {
1650 atomic_clear_int(&lp->lwp_mpflags,
1651 LWP_MP_WSTOP);
1652 --p->p_nstopped;
1653 } else {
1654 if (bootverbose)
1655 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n",
1656 p->p_pid, lp->lwp_tid);
1657 }
1658 /* FALLTHROUGH */
1659
1660 case LSSTOP:
1661 /*
1662 * This handles any lwp's waiting in a tsleep with
1663 * SIGCATCH.
1664 */
1665 lwp_signotify(lp);
1666 break;
1667
1668 }
1669 lwkt_reltoken(&lp->lwp_token);
1670 LWPRELE(lp);
1671 }
1672
1673 /*
1674 * This handles any lwp's waiting in tstop(). We have interlocked
1675 * the setting of p_stat by acquiring and releasing each lpw's
1676 * token.
1677 */
1678 wakeup(p);
1679 }
1680
1681 /*
1682 * Wait for all threads except the current thread to stop.
1683 */
1684 static void
1685 proc_stopwait(struct proc *p)
1686 {
1687 while ((p->p_stat == SSTOP || p->p_stat == SCORE) &&
1688 p->p_nstopped < p->p_nthreads - 1) {
1689 tsleep_interlock(&p->p_nstopped, 0);
1690 if (p->p_nstopped < p->p_nthreads - 1) {
1691 tsleep(&p->p_nstopped, PINTERLOCKED, "stopwt", hz);
1692 }
1693 }
1694 }
1695
1696 /*
1697 * No requirements.
1698 */
1699 static int
1700 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1701 {
1702 sigset_t savedmask, set;
1703 struct proc *p = curproc;
1704 struct lwp *lp = curthread->td_lwp;
1705 int error, sig, hz, timevalid = 0;
1706 struct timespec rts, ets, ts;
1707 struct timeval tv;
1708
1709 error = 0;
1710 sig = 0;
1711 ets.tv_sec = 0; /* silence compiler warning */
1712 ets.tv_nsec = 0; /* silence compiler warning */
1713 SIG_CANTMASK(waitset);
1714 savedmask = lp->lwp_sigmask;
1715
1716 if (timeout) {
1717 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1718 timeout->tv_nsec < 1000000000) {
1719 timevalid = 1;
1720 getnanouptime(&rts);
1721 ets = rts;
1722 timespecadd(&ets, timeout);
1723 }
1724 }
1725
1726 for (;;) {
1727 set = lwp_sigpend(lp);
1728 SIGSETAND(set, waitset);
1729 if ((sig = sig_ffs(&set)) != 0) {
1730 SIGFILLSET(lp->lwp_sigmask);
1731 SIGDELSET(lp->lwp_sigmask, sig);
1732 SIG_CANTMASK(lp->lwp_sigmask);
1733 sig = issignal(lp, 1, 0);
1734 /*
1735 * It may be a STOP signal, in the case, issignal
1736 * returns 0, because we may stop there, and new
1737 * signal can come in, we should restart if we got
1738 * nothing.
1739 */
1740 if (sig == 0)
1741 continue;
1742 else
1743 break;
1744 }
1745
1746 /*
1747 * Previous checking got nothing, and we retried but still
1748 * got nothing, we should return the error status.
1749 */
1750 if (error)
1751 break;
1752
1753 /*
1754 * POSIX says this must be checked after looking for pending
1755 * signals.
1756 */
1757 if (timeout) {
1758 if (timevalid == 0) {
1759 error = EINVAL;
1760 break;
1761 }
1762 getnanouptime(&rts);
1763 if (timespeccmp(&rts, &ets, >=)) {
1764 error = EAGAIN;
1765 break;
1766 }
1767 ts = ets;
1768 timespecsub(&ts, &rts);
1769 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1770 hz = tvtohz_high(&tv);
1771 } else {
1772 hz = 0;
1773 }
1774
1775 lp->lwp_sigmask = savedmask;
1776 SIGSETNAND(lp->lwp_sigmask, waitset);
1777 /*
1778 * We won't ever be woken up. Instead, our sleep will
1779 * be broken in lwpsignal().
1780 */
1781 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1782 if (timeout) {
1783 if (error == ERESTART) {
1784 /* can not restart a timeout wait. */
1785 error = EINTR;
1786 } else if (error == EAGAIN) {
1787 /* will calculate timeout by ourself. */
1788 error = 0;
1789 }
1790 }
1791 /* Retry ... */
1792 }
1793
1794 lp->lwp_sigmask = savedmask;
1795 if (sig) {
1796 error = 0;
1797 bzero(info, sizeof(*info));
1798 info->si_signo = sig;
1799 spin_lock(&lp->lwp_spin);
1800 lwp_delsig(lp, sig, 1); /* take the signal! */
1801 spin_unlock(&lp->lwp_spin);
1802
1803 if (sig == SIGKILL) {
1804 sigexit(lp, sig);
1805 /* NOT REACHED */
1806 }
1807 }
1808
1809 return (error);
1810 }
1811
1812 /*
1813 * MPALMOSTSAFE
1814 */
1815 int
1816 sys_sigtimedwait(struct sigtimedwait_args *uap)
1817 {
1818 struct timespec ts;
1819 struct timespec *timeout;
1820 sigset_t set;
1821 siginfo_t info;
1822 int error;
1823
1824 if (uap->timeout) {
1825 error = copyin(uap->timeout, &ts, sizeof(ts));
1826 if (error)
1827 return (error);
1828 timeout = &ts;
1829 } else {
1830 timeout = NULL;
1831 }
1832 error = copyin(uap->set, &set, sizeof(set));
1833 if (error)
1834 return (error);
1835 error = kern_sigtimedwait(set, &info, timeout);
1836 if (error)
1837 return (error);
1838 if (uap->info)
1839 error = copyout(&info, uap->info, sizeof(info));
1840 /* Repost if we got an error. */
1841 /*
1842 * XXX lwp
1843 *
1844 * This could transform a thread-specific signal to another
1845 * thread / process pending signal.
1846 */
1847 if (error) {
1848 ksignal(curproc, info.si_signo);
1849 } else {
1850 uap->sysmsg_result = info.si_signo;
1851 }
1852 return (error);
1853 }
1854
1855 /*
1856 * MPALMOSTSAFE
1857 */
1858 int
1859 sys_sigwaitinfo(struct sigwaitinfo_args *uap)
1860 {
1861 siginfo_t info;
1862 sigset_t set;
1863 int error;
1864
1865 error = copyin(uap->set, &set, sizeof(set));
1866 if (error)
1867 return (error);
1868 error = kern_sigtimedwait(set, &info, NULL);
1869 if (error)
1870 return (error);
1871 if (uap->info)
1872 error = copyout(&info, uap->info, sizeof(info));
1873 /* Repost if we got an error. */
1874 /*
1875 * XXX lwp
1876 *
1877 * This could transform a thread-specific signal to another
1878 * thread / process pending signal.
1879 */
1880 if (error) {
1881 ksignal(curproc, info.si_signo);
1882 } else {
1883 uap->sysmsg_result = info.si_signo;
1884 }
1885 return (error);
1886 }
1887
1888 /*
1889 * If the current process has received a signal that would interrupt a
1890 * system call, return EINTR or ERESTART as appropriate.
1891 */
1892 int
1893 iscaught(struct lwp *lp)
1894 {
1895 struct proc *p = lp->lwp_proc;
1896 int sig;
1897
1898 if (p) {
1899 if ((sig = CURSIG(lp)) != 0) {
1900 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1901 return (EINTR);
1902 return (ERESTART);
1903 }
1904 }
1905 return(EWOULDBLOCK);
1906 }
1907
1908 /*
1909 * If the current lwp/proc has received a signal (should be caught or cause
1910 * termination, should interrupt current syscall), return the signal number.
1911 * Stop signals with default action are processed immediately, then cleared;
1912 * they aren't returned. This is checked after each entry to the system for
1913 * a syscall or trap (though this can usually be done without calling issignal
1914 * by checking the pending signal masks in the CURSIG macro).
1915 *
1916 * This routine is called via CURSIG/__cursig. We will acquire and release
1917 * p->p_token but if the caller needs to interlock the test the caller must
1918 * also hold p->p_token.
1919 *
1920 * while (sig = CURSIG(curproc))
1921 * postsig(sig);
1922 */
1923 int
1924 issignal(struct lwp *lp, int maytrace, int *ptokp)
1925 {
1926 struct proc *p = lp->lwp_proc;
1927 sigset_t mask;
1928 int sig, prop;
1929 int haveptok;
1930
1931 for (;;) {
1932 int traced = (p->p_flags & P_TRACED) || (p->p_stops & S_SIG);
1933
1934 haveptok = 0;
1935
1936 /*
1937 * If this process is supposed to stop, stop this thread.
1938 */
1939 if (STOPLWP(p, lp)) {
1940 lwkt_gettoken(&p->p_token);
1941 tstop();
1942 lwkt_reltoken(&p->p_token);
1943 }
1944
1945 /*
1946 * Quick check without token
1947 */
1948 mask = lwp_sigpend(lp);
1949 SIGSETNAND(mask, lp->lwp_sigmask);
1950 if (p->p_flags & P_PPWAIT)
1951 SIG_STOPSIGMASK(mask);
1952 if (SIGISEMPTY(mask)) /* no signal to send */
1953 return (0);
1954
1955 /*
1956 * If the signal is a member of the process signal set
1957 * we need p_token (even if it is also a member of the
1958 * lwp signal set).
1959 */
1960 sig = sig_ffs(&mask);
1961 if (SIGISMEMBER(p->p_siglist, sig)) {
1962 /*
1963 * Recheck with token
1964 */
1965 haveptok = 1;
1966 lwkt_gettoken(&p->p_token);
1967
1968 mask = lwp_sigpend(lp);
1969 SIGSETNAND(mask, lp->lwp_sigmask);
1970 if (p->p_flags & P_PPWAIT)
1971 SIG_STOPSIGMASK(mask);
1972 if (SIGISEMPTY(mask)) { /* no signal to send */
1973 /* haveptok is TRUE */
1974 lwkt_reltoken(&p->p_token);
1975 return (0);
1976 }
1977 sig = sig_ffs(&mask);
1978 }
1979
1980 STOPEVENT(p, S_SIG, sig);
1981
1982 /*
1983 * We should see pending but ignored signals
1984 * only if P_TRACED was on when they were posted.
1985 */
1986 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
1987 spin_lock(&lp->lwp_spin);
1988 lwp_delsig(lp, sig, haveptok);
1989 spin_unlock(&lp->lwp_spin);
1990 if (haveptok)
1991 lwkt_reltoken(&p->p_token);
1992 continue;
1993 }
1994 if (maytrace &&
1995 (p->p_flags & P_TRACED) &&
1996 (p->p_flags & P_PPWAIT) == 0) {
1997 /*
1998 * If traced, always stop, and stay stopped until
1999 * released by the parent.
2000 *
2001 * NOTE: SSTOP may get cleared during the loop,
2002 * but we do not re-notify the parent if we have
2003 * to loop several times waiting for the parent
2004 * to let us continue.
2005 *
2006 * XXX not sure if this is still true
2007 */
2008 if (haveptok == 0) {
2009 lwkt_gettoken(&p->p_token);
2010 haveptok = 1;
2011 }
2012 p->p_xstat = sig;
2013 proc_stop(p, SSTOP);
2014 do {
2015 tstop();
2016 } while (!trace_req(p) && (p->p_flags & P_TRACED));
2017
2018 /*
2019 * If parent wants us to take the signal,
2020 * then it will leave it in p->p_xstat;
2021 * otherwise we just look for signals again.
2022 */
2023 spin_lock(&lp->lwp_spin);
2024 lwp_delsig(lp, sig, 1); /* clear old signal */
2025 spin_unlock(&lp->lwp_spin);
2026 sig = p->p_xstat;
2027 if (sig == 0) {
2028 /* haveptok is TRUE */
2029 lwkt_reltoken(&p->p_token);
2030 continue;
2031 }
2032
2033 /*
2034 * Put the new signal into p_siglist. If the
2035 * signal is being masked, look for other signals.
2036 *
2037 * XXX lwp might need a call to ksignal()
2038 */
2039 SIGADDSET_ATOMIC(p->p_siglist, sig);
2040 if (SIGISMEMBER(lp->lwp_sigmask, sig)) {
2041 /* haveptok is TRUE */
2042 lwkt_reltoken(&p->p_token);
2043 continue;
2044 }
2045
2046 /*
2047 * If the traced bit got turned off, go back up
2048 * to the top to rescan signals. This ensures
2049 * that p_sig* and ps_sigact are consistent.
2050 */
2051 if ((p->p_flags & P_TRACED) == 0) {
2052 /* haveptok is TRUE */
2053 lwkt_reltoken(&p->p_token);
2054 continue;
2055 }
2056 }
2057
2058 /*
2059 * p_token may be held here
2060 */
2061 prop = sigprop(sig);
2062
2063 /*
2064 * Decide whether the signal should be returned.
2065 * Return the signal's number, or fall through
2066 * to clear it from the pending mask.
2067 */
2068 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
2069 case (intptr_t)SIG_DFL:
2070 /*
2071 * Don't take default actions on system processes.
2072 */
2073 if (p->p_pid <= 1) {
2074 #ifdef DIAGNOSTIC
2075 /*
2076 * Are you sure you want to ignore SIGSEGV
2077 * in init? XXX
2078 */
2079 kprintf("Process (pid %lu) got signal %d\n",
2080 (u_long)p->p_pid, sig);
2081 #endif
2082 break; /* == ignore */
2083 }
2084
2085 /*
2086 * Handle the in-kernel checkpoint action
2087 */
2088 if (prop & SA_CKPT) {
2089 if (haveptok == 0) {
2090 lwkt_gettoken(&p->p_token);
2091 haveptok = 1;
2092 }
2093 checkpoint_signal_handler(lp);
2094 break;
2095 }
2096
2097 /*
2098 * If there is a pending stop signal to process
2099 * with default action, stop here,
2100 * then clear the signal. However,
2101 * if process is member of an orphaned
2102 * process group, ignore tty stop signals.
2103 */
2104 if (prop & SA_STOP) {
2105 if (haveptok == 0) {
2106 lwkt_gettoken(&p->p_token);
2107 haveptok = 1;
2108 }
2109 if (p->p_flags & P_TRACED ||
2110 (p->p_pgrp->pg_jobc == 0 &&
2111 prop & SA_TTYSTOP))
2112 break; /* == ignore */
2113 if ((p->p_flags & P_WEXIT) == 0) {
2114 p->p_xstat = sig;
2115 proc_stop(p, SSTOP);
2116 tstop();
2117 }
2118 break;
2119 } else if (prop & SA_IGNORE) {
2120 /*
2121 * Except for SIGCONT, shouldn't get here.
2122 * Default action is to ignore; drop it.
2123 */
2124 break; /* == ignore */
2125 } else {
2126 if (ptokp)
2127 *ptokp = haveptok;
2128 else if (haveptok)
2129 lwkt_reltoken(&p->p_token);
2130 return (sig);
2131 }
2132
2133 /*NOTREACHED*/
2134
2135 case (intptr_t)SIG_IGN:
2136 /*
2137 * Masking above should prevent us ever trying
2138 * to take action on an ignored signal other
2139 * than SIGCONT, unless process is traced.
2140 */
2141 if ((prop & SA_CONT) == 0 &&
2142 (p->p_flags & P_TRACED) == 0)
2143 kprintf("issignal\n");
2144 break; /* == ignore */
2145
2146 default:
2147 /*
2148 * This signal has an action, let
2149 * postsig() process it.
2150 */
2151 if (ptokp)
2152 *ptokp = haveptok;
2153 else if (haveptok)
2154 lwkt_reltoken(&p->p_token);
2155 return (sig);
2156 }
2157 spin_lock(&lp->lwp_spin);
2158 lwp_delsig(lp, sig, haveptok); /* take the signal! */
2159 spin_unlock(&lp->lwp_spin);
2160
2161 if (haveptok)
2162 lwkt_reltoken(&p->p_token);
2163 }
2164 /* NOTREACHED */
2165 }
2166
2167 /*
2168 * Take the action for the specified signal from the current set of
2169 * pending signals.
2170 *
2171 * haveptok indicates whether the caller is holding p->p_token. If the
2172 * caller is, we are responsible for releasing it.
2173 *
2174 * This routine can only be called from the top-level trap from usermode.
2175 * It is expecting to be able to modify the top-level stack frame.
2176 */
2177 void
2178 postsig(int sig, int haveptok)
2179 {
2180 struct lwp *lp = curthread->td_lwp;
2181 struct proc *p = lp->lwp_proc;
2182 struct sigacts *ps = p->p_sigacts;
2183 sig_t action;
2184 sigset_t returnmask;
2185 int code;
2186
2187 KASSERT(sig != 0, ("postsig"));
2188
2189 /*
2190 * If we are a virtual kernel running an emulated user process
2191 * context, switch back to the virtual kernel context before
2192 * trying to post the signal.
2193 */
2194 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
2195 struct trapframe *tf = lp->lwp_md.md_regs;
2196 tf->tf_trapno = 0;
2197 vkernel_trap(lp, tf);
2198 }
2199
2200 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
2201
2202 spin_lock(&lp->lwp_spin);
2203 lwp_delsig(lp, sig, haveptok);
2204 spin_unlock(&lp->lwp_spin);
2205 action = ps->ps_sigact[_SIG_IDX(sig)];
2206 #ifdef KTRACE
2207 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
2208 ktrpsig(lp, sig, action, lp->lwp_flags & LWP_OLDMASK ?
2209 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0);
2210 #endif
2211 /*
2212 * We don't need p_token after this point.
2213 */
2214 if (haveptok)
2215 lwkt_reltoken(&p->p_token);
2216
2217 STOPEVENT(p, S_SIG, sig);
2218
2219 if (action == SIG_DFL) {
2220 /*
2221 * Default action, where the default is to kill
2222 * the process. (Other cases were ignored above.)
2223 */
2224 sigexit(lp, sig);
2225 /* NOTREACHED */
2226 } else {
2227 /*
2228 * If we get here, the signal must be caught.
2229 */
2230 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig),
2231 ("postsig action"));
2232
2233 /*
2234 * Reset the signal handler if asked to
2235 */
2236 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
2237 /*
2238 * See kern_sigaction() for origin of this code.
2239 */
2240 SIGDELSET(p->p_sigcatch, sig);
2241 if (sig != SIGCONT &&
2242 sigprop(sig) & SA_IGNORE)
2243 SIGADDSET(p->p_sigignore, sig);
2244 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
2245 }
2246
2247 /*
2248 * Set the signal mask and calculate the mask to restore
2249 * when the signal function returns.
2250 *
2251 * Special case: user has done a sigsuspend. Here the
2252 * current mask is not of interest, but rather the
2253 * mask from before the sigsuspend is what we want
2254 * restored after the signal processing is completed.
2255 */
2256 if (lp->lwp_flags & LWP_OLDMASK) {
2257 returnmask = lp->lwp_oldsigmask;
2258 lp->lwp_flags &= ~LWP_OLDMASK;
2259 } else {
2260 returnmask = lp->lwp_sigmask;
2261 }
2262
2263 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
2264 if (!SIGISMEMBER(ps->ps_signodefer, sig))
2265 SIGADDSET(lp->lwp_sigmask, sig);
2266
2267 lp->lwp_ru.ru_nsignals++;
2268 if (lp->lwp_sig != sig) {
2269 code = 0;
2270 } else {
2271 code = lp->lwp_code;
2272 lp->lwp_code = 0;
2273 lp->lwp_sig = 0;
2274 }
2275 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
2276 }
2277 }
2278
2279 /*
2280 * Kill the current process for stated reason.
2281 */
2282 void
2283 killproc(struct proc *p, char *why)
2284 {
2285 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n",
2286 p->p_pid, p->p_comm,
2287 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
2288 ksignal(p, SIGKILL);
2289 }
2290
2291 /*
2292 * Force the current process to exit with the specified signal, dumping core
2293 * if appropriate. We bypass the normal tests for masked and caught signals,
2294 * allowing unrecoverable failures to terminate the process without changing
2295 * signal state. Mark the accounting record with the signal termination.
2296 * If dumping core, save the signal number for the debugger. Calls exit and
2297 * does not return.
2298 *
2299 * This routine does not return.
2300 */
2301 void
2302 sigexit(struct lwp *lp, int sig)
2303 {
2304 struct proc *p = lp->lwp_proc;
2305
2306 lwkt_gettoken(&p->p_token);
2307 p->p_acflag |= AXSIG;
2308 if (sigprop(sig) & SA_CORE) {
2309 lp->lwp_sig = sig;
2310
2311 /*
2312 * All threads must be stopped before we can safely coredump.
2313 * Stop threads using SCORE, which cannot be overridden.
2314 */
2315 if (p->p_stat != SCORE) {
2316 proc_stop(p, SCORE);
2317 proc_stopwait(p);
2318
2319 if (coredump(lp, sig) == 0)
2320 sig |= WCOREFLAG;
2321 p->p_stat = SSTOP;
2322 }
2323
2324 /*
2325 * Log signals which would cause core dumps
2326 * (Log as LOG_INFO to appease those who don't want
2327 * these messages.)
2328 * XXX : Todo, as well as euid, write out ruid too
2329 */
2330 if (kern_logsigexit) {
2331 log(LOG_INFO,
2332 "pid %d (%s), uid %d: exited on signal %d%s\n",
2333 p->p_pid, p->p_comm,
2334 p->p_ucred ? p->p_ucred->cr_uid : -1,
2335 sig &~ WCOREFLAG,
2336 sig & WCOREFLAG ? " (core dumped)" : "");
2337 }
2338 }
2339 lwkt_reltoken(&p->p_token);
2340 exit1(W_EXITCODE(0, sig));
2341 /* NOTREACHED */
2342 }
2343
2344 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
2345 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
2346 sizeof(corefilename), "process corefile name format string");
2347
2348 /*
2349 * expand_name(name, uid, pid)
2350 * Expand the name described in corefilename, using name, uid, and pid.
2351 * corefilename is a kprintf-like string, with three format specifiers:
2352 * %N name of process ("name")
2353 * %P process id (pid)
2354 * %U user id (uid)
2355 * For example, "%N.core" is the default; they can be disabled completely
2356 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
2357 * This is controlled by the sysctl variable kern.corefile (see above).
2358 */
2359
2360 static char *
2361 expand_name(const char *name, uid_t uid, pid_t pid)
2362 {
2363 char *temp;
2364 char buf[11]; /* Buffer for pid/uid -- max 4B */
2365 int i, n;
2366 char *format = corefilename;
2367 size_t namelen;
2368
2369 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
2370 if (temp == NULL)
2371 return NULL;
2372 namelen = strlen(name);
2373 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
2374 int l;
2375 switch (format[i]) {
2376 case '%': /* Format character */
2377 i++;
2378 switch (format[i]) {
2379 case '%':
2380 temp[n++] = '%';
2381 break;
2382 case 'N': /* process name */
2383 if ((n + namelen) > MAXPATHLEN) {
2384 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2385 pid, name, uid, temp, name);
2386 kfree(temp, M_TEMP);
2387 return NULL;
2388 }
2389 memcpy(temp+n, name, namelen);
2390 n += namelen;
2391 break;
2392 case 'P': /* process id */
2393 l = ksprintf(buf, "%u", pid);
2394 if ((n + l) > MAXPATHLEN) {
2395 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2396 pid, name, uid, temp, name);
2397 kfree(temp, M_TEMP);
2398 return NULL;
2399 }
2400 memcpy(temp+n, buf, l);
2401 n += l;
2402 break;
2403 case 'U': /* user id */
2404 l = ksprintf(buf, "%u", uid);
2405 if ((n + l) > MAXPATHLEN) {
2406 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2407 pid, name, uid, temp, name);
2408 kfree(temp, M_TEMP);
2409 return NULL;
2410 }
2411 memcpy(temp+n, buf, l);
2412 n += l;
2413 break;
2414 default:
2415 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
2416 }
2417 break;
2418 default:
2419 temp[n++] = format[i];
2420 }
2421 }
2422 temp[n] = '\0';
2423 return temp;
2424 }
2425
2426 /*
2427 * Dump a process' core. The main routine does some
2428 * policy checking, and creates the name of the coredump;
2429 * then it passes on a vnode and a size limit to the process-specific
2430 * coredump routine if there is one; if there _is not_ one, it returns
2431 * ENOSYS; otherwise it returns the error from the process-specific routine.
2432 *
2433 * The parameter `lp' is the lwp which triggered the coredump.
2434 */
2435
2436 static int
2437 coredump(struct lwp *lp, int sig)
2438 {
2439 struct proc *p = lp->lwp_proc;
2440 struct vnode *vp;
2441 struct ucred *cred = p->p_ucred;
2442 struct flock lf;
2443 struct nlookupdata nd;
2444 struct vattr vattr;
2445 int error, error1;
2446 char *name; /* name of corefile */
2447 off_t limit;
2448
2449 STOPEVENT(p, S_CORE, 0);
2450
2451 if (((sugid_coredump == 0) && p->p_flags & P_SUGID) || do_coredump == 0)
2452 return (EFAULT);
2453
2454 /*
2455 * Note that the bulk of limit checking is done after
2456 * the corefile is created. The exception is if the limit
2457 * for corefiles is 0, in which case we don't bother
2458 * creating the corefile at all. This layout means that
2459 * a corefile is truncated instead of not being created,
2460 * if it is larger than the limit.
2461 */
2462 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
2463 if (limit == 0)
2464 return EFBIG;
2465
2466 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
2467 if (name == NULL)
2468 return (EINVAL);
2469 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
2470 if (error == 0)
2471 error = vn_open(&nd, NULL,
2472 O_CREAT | FWRITE | O_NOFOLLOW,
2473 S_IRUSR | S_IWUSR);
2474 kfree(name, M_TEMP);
2475 if (error) {
2476 nlookup_done(&nd);
2477 return (error);
2478 }
2479 vp = nd.nl_open_vp;
2480 nd.nl_open_vp = NULL;
2481 nlookup_done(&nd);
2482
2483 vn_unlock(vp);
2484 lf.l_whence = SEEK_SET;
2485 lf.l_start = 0;
2486 lf.l_len = 0;
2487 lf.l_type = F_WRLCK;
2488 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
2489 if (error)
2490 goto out2;
2491
2492 /* Don't dump to non-regular files or files with links. */
2493 if (vp->v_type != VREG ||
2494 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
2495 error = EFAULT;
2496 goto out1;
2497 }
2498
2499 /* Don't dump to files current user does not own */
2500 if (vattr.va_uid != p->p_ucred->cr_uid) {
2501 error = EFAULT;
2502 goto out1;
2503 }
2504
2505 VATTR_NULL(&vattr);
2506 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2507 vattr.va_size = 0;
2508 VOP_SETATTR(vp, &vattr, cred);
2509 p->p_acflag |= ACORE;
2510 vn_unlock(vp);
2511
2512 error = p->p_sysent->sv_coredump ?
2513 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS;
2514
2515 out1:
2516 lf.l_type = F_UNLCK;
2517 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
2518 out2:
2519 error1 = vn_close(vp, FWRITE, NULL);
2520 if (error == 0)
2521 error = error1;
2522 return (error);
2523 }
2524
2525 /*
2526 * Nonexistent system call-- signal process (may want to handle it).
2527 * Flag error in case process won't see signal immediately (blocked or ignored).
2528 *
2529 * MPALMOSTSAFE
2530 */
2531 /* ARGSUSED */
2532 int
2533 sys_nosys(struct nosys_args *args)
2534 {
2535 lwpsignal(curproc, curthread->td_lwp, SIGSYS);
2536 return (EINVAL);
2537 }
2538
2539 /*
2540 * Send a SIGIO or SIGURG signal to a process or process group using
2541 * stored credentials rather than those of the current process.
2542 */
2543 void
2544 pgsigio(struct sigio *sigio, int sig, int checkctty)
2545 {
2546 if (sigio == NULL)
2547 return;
2548
2549 if (sigio->sio_pgid > 0) {
2550 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
2551 sigio->sio_proc))
2552 ksignal(sigio->sio_proc, sig);
2553 } else if (sigio->sio_pgid < 0) {
2554 struct proc *p;
2555 struct pgrp *pg = sigio->sio_pgrp;
2556
2557 /*
2558 * Must interlock all signals against fork
2559 */
2560 pgref(pg);
2561 lockmgr(&pg->pg_lock, LK_EXCLUSIVE);
2562 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
2563 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
2564 (checkctty == 0 || (p->p_flags & P_CONTROLT)))
2565 ksignal(p, sig);
2566 }
2567 lockmgr(&pg->pg_lock, LK_RELEASE);
2568 pgrel(pg);
2569 }
2570 }
2571
2572 static int
2573 filt_sigattach(struct knote *kn)
2574 {
2575 struct proc *p = curproc;
2576
2577 kn->kn_ptr.p_proc = p;
2578 kn->kn_flags |= EV_CLEAR; /* automatically set */
2579
2580 /* XXX lock the proc here while adding to the list? */
2581 knote_insert(&p->p_klist, kn);
2582
2583 return (0);
2584 }
2585
2586 static void
2587 filt_sigdetach(struct knote *kn)
2588 {
2589 struct proc *p = kn->kn_ptr.p_proc;
2590
2591 knote_remove(&p->p_klist, kn);
2592 }
2593
2594 /*
2595 * signal knotes are shared with proc knotes, so we apply a mask to
2596 * the hint in order to differentiate them from process hints. This
2597 * could be avoided by using a signal-specific knote list, but probably
2598 * isn't worth the trouble.
2599 */
2600 static int
2601 filt_signal(struct knote *kn, long hint)
2602 {
2603 if (hint & NOTE_SIGNAL) {
2604 hint &= ~NOTE_SIGNAL;
2605
2606 if (kn->kn_id == hint)
2607 kn->kn_data++;
2608 }
2609 return (kn->kn_data != 0);
2610 }
DragonFly BSD