?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
ifq: Switch to drop-head for default enqueue method.
[dragonfly.git] / sys / kern / kern_sig.c
blob8f3018ebb75fd75efe9ea3867a456aefc197fa22
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, with pcred pc, send the signal sig to process q?
98 */
99 #define CANSIGNAL(q, sig) \
100 (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \
101 ((sig) == SIGCONT && (q)->p_session == curproc->p_session))
102
103 /*
104 * Policy -- Can real uid ruid with ucred uc send a signal to process q?
105 */
106 #define CANSIGIO(ruid, uc, q) \
107 ((uc)->cr_uid == 0 || \
108 (ruid) == (q)->p_ucred->cr_ruid || \
109 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \
110 (ruid) == (q)->p_ucred->cr_uid || \
111 (uc)->cr_uid == (q)->p_ucred->cr_uid)
112
113 int sugid_coredump;
114 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW,
115 &sugid_coredump, 0, "Enable coredumping set user/group ID processes");
116
117 static int do_coredump = 1;
118 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
119 &do_coredump, 0, "Enable/Disable coredumps");
120
121 /*
122 * Signal properties and actions.
123 * The array below categorizes the signals and their default actions
124 * according to the following properties:
125 */
126 #define SA_KILL 0x01 /* terminates process by default */
127 #define SA_CORE 0x02 /* ditto and coredumps */
128 #define SA_STOP 0x04 /* suspend process */
129 #define SA_TTYSTOP 0x08 /* ditto, from tty */
130 #define SA_IGNORE 0x10 /* ignore by default */
131 #define SA_CONT 0x20 /* continue if suspended */
132 #define SA_CANTMASK 0x40 /* non-maskable, catchable */
133 #define SA_CKPT 0x80 /* checkpoint process */
134
135
136 static int sigproptbl[NSIG] = {
137 SA_KILL, /* SIGHUP */
138 SA_KILL, /* SIGINT */
139 SA_KILL|SA_CORE, /* SIGQUIT */
140 SA_KILL|SA_CORE, /* SIGILL */
141 SA_KILL|SA_CORE, /* SIGTRAP */
142 SA_KILL|SA_CORE, /* SIGABRT */
143 SA_KILL|SA_CORE, /* SIGEMT */
144 SA_KILL|SA_CORE, /* SIGFPE */
145 SA_KILL, /* SIGKILL */
146 SA_KILL|SA_CORE, /* SIGBUS */
147 SA_KILL|SA_CORE, /* SIGSEGV */
148 SA_KILL|SA_CORE, /* SIGSYS */
149 SA_KILL, /* SIGPIPE */
150 SA_KILL, /* SIGALRM */
151 SA_KILL, /* SIGTERM */
152 SA_IGNORE, /* SIGURG */
153 SA_STOP, /* SIGSTOP */
154 SA_STOP|SA_TTYSTOP, /* SIGTSTP */
155 SA_IGNORE|SA_CONT, /* SIGCONT */
156 SA_IGNORE, /* SIGCHLD */
157 SA_STOP|SA_TTYSTOP, /* SIGTTIN */
158 SA_STOP|SA_TTYSTOP, /* SIGTTOU */
159 SA_IGNORE, /* SIGIO */
160 SA_KILL, /* SIGXCPU */
161 SA_KILL, /* SIGXFSZ */
162 SA_KILL, /* SIGVTALRM */
163 SA_KILL, /* SIGPROF */
164 SA_IGNORE, /* SIGWINCH */
165 SA_IGNORE, /* SIGINFO */
166 SA_KILL, /* SIGUSR1 */
167 SA_KILL, /* SIGUSR2 */
168 SA_IGNORE, /* SIGTHR */
169 SA_CKPT, /* SIGCKPT */
170 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */
171 SA_IGNORE,
172 SA_IGNORE,
173 SA_IGNORE,
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
202 };
203
204 static __inline int
205 sigprop(int sig)
206 {
207
208 if (sig > 0 && sig < NSIG)
209 return (sigproptbl[_SIG_IDX(sig)]);
210 return (0);
211 }
212
213 static __inline int
214 sig_ffs(sigset_t *set)
215 {
216 int i;
217
218 for (i = 0; i < _SIG_WORDS; i++)
219 if (set->__bits[i])
220 return (ffs(set->__bits[i]) + (i * 32));
221 return (0);
222 }
223
224 /*
225 * No requirements.
226 */
227 int
228 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact)
229 {
230 struct thread *td = curthread;
231 struct proc *p = td->td_proc;
232 struct lwp *lp;
233 struct sigacts *ps = p->p_sigacts;
234
235 if (sig <= 0 || sig > _SIG_MAXSIG)
236 return (EINVAL);
237
238 lwkt_gettoken(&p->p_token);
239
240 if (oact) {
241 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
242 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
243 oact->sa_flags = 0;
244 if (SIGISMEMBER(ps->ps_sigonstack, sig))
245 oact->sa_flags |= SA_ONSTACK;
246 if (!SIGISMEMBER(ps->ps_sigintr, sig))
247 oact->sa_flags |= SA_RESTART;
248 if (SIGISMEMBER(ps->ps_sigreset, sig))
249 oact->sa_flags |= SA_RESETHAND;
250 if (SIGISMEMBER(ps->ps_signodefer, sig))
251 oact->sa_flags |= SA_NODEFER;
252 if (SIGISMEMBER(ps->ps_siginfo, sig))
253 oact->sa_flags |= SA_SIGINFO;
254 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP)
255 oact->sa_flags |= SA_NOCLDSTOP;
256 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT)
257 oact->sa_flags |= SA_NOCLDWAIT;
258 }
259 if (act) {
260 /*
261 * Check for invalid requests. KILL and STOP cannot be
262 * caught.
263 */
264 if (sig == SIGKILL || sig == SIGSTOP) {
265 if (act->sa_handler != SIG_DFL) {
266 lwkt_reltoken(&p->p_token);
267 return (EINVAL);
268 }
269 }
270
271 /*
272 * Change setting atomically.
273 */
274 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
275 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
276 if (act->sa_flags & SA_SIGINFO) {
277 ps->ps_sigact[_SIG_IDX(sig)] =
278 (__sighandler_t *)act->sa_sigaction;
279 SIGADDSET(ps->ps_siginfo, sig);
280 } else {
281 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
282 SIGDELSET(ps->ps_siginfo, sig);
283 }
284 if (!(act->sa_flags & SA_RESTART))
285 SIGADDSET(ps->ps_sigintr, sig);
286 else
287 SIGDELSET(ps->ps_sigintr, sig);
288 if (act->sa_flags & SA_ONSTACK)
289 SIGADDSET(ps->ps_sigonstack, sig);
290 else
291 SIGDELSET(ps->ps_sigonstack, sig);
292 if (act->sa_flags & SA_RESETHAND)
293 SIGADDSET(ps->ps_sigreset, sig);
294 else
295 SIGDELSET(ps->ps_sigreset, sig);
296 if (act->sa_flags & SA_NODEFER)
297 SIGADDSET(ps->ps_signodefer, sig);
298 else
299 SIGDELSET(ps->ps_signodefer, sig);
300 if (sig == SIGCHLD) {
301 if (act->sa_flags & SA_NOCLDSTOP)
302 p->p_sigacts->ps_flag |= PS_NOCLDSTOP;
303 else
304 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP;
305 if (act->sa_flags & SA_NOCLDWAIT) {
306 /*
307 * Paranoia: since SA_NOCLDWAIT is implemented
308 * by reparenting the dying child to PID 1 (and
309 * trust it to reap the zombie), PID 1 itself
310 * is forbidden to set SA_NOCLDWAIT.
311 */
312 if (p->p_pid == 1)
313 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
314 else
315 p->p_sigacts->ps_flag |= PS_NOCLDWAIT;
316 } else {
317 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
318 }
319 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
320 ps->ps_flag |= PS_CLDSIGIGN;
321 else
322 ps->ps_flag &= ~PS_CLDSIGIGN;
323 }
324 /*
325 * Set bit in p_sigignore for signals that are set to SIG_IGN,
326 * and for signals set to SIG_DFL where the default is to
327 * ignore. However, don't put SIGCONT in p_sigignore, as we
328 * have to restart the process.
329 *
330 * Also remove the signal from the process and lwp signal
331 * list.
332 */
333 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
334 (sigprop(sig) & SA_IGNORE &&
335 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
336 SIGDELSET(p->p_siglist, sig);
337 FOREACH_LWP_IN_PROC(lp, p) {
338 spin_lock(&lp->lwp_spin);
339 SIGDELSET(lp->lwp_siglist, sig);
340 spin_unlock(&lp->lwp_spin);
341 }
342 if (sig != SIGCONT) {
343 /* easier in ksignal */
344 SIGADDSET(p->p_sigignore, sig);
345 }
346 SIGDELSET(p->p_sigcatch, sig);
347 } else {
348 SIGDELSET(p->p_sigignore, sig);
349 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
350 SIGDELSET(p->p_sigcatch, sig);
351 else
352 SIGADDSET(p->p_sigcatch, sig);
353 }
354 }
355 lwkt_reltoken(&p->p_token);
356 return (0);
357 }
358
359 int
360 sys_sigaction(struct sigaction_args *uap)
361 {
362 struct sigaction act, oact;
363 struct sigaction *actp, *oactp;
364 int error;
365
366 actp = (uap->act != NULL) ? &act : NULL;
367 oactp = (uap->oact != NULL) ? &oact : NULL;
368 if (actp) {
369 error = copyin(uap->act, actp, sizeof(act));
370 if (error)
371 return (error);
372 }
373 error = kern_sigaction(uap->sig, actp, oactp);
374 if (oactp && !error) {
375 error = copyout(oactp, uap->oact, sizeof(oact));
376 }
377 return (error);
378 }
379
380 /*
381 * Initialize signal state for process 0;
382 * set to ignore signals that are ignored by default.
383 */
384 void
385 siginit(struct proc *p)
386 {
387 int i;
388
389 for (i = 1; i <= NSIG; i++)
390 if (sigprop(i) & SA_IGNORE && i != SIGCONT)
391 SIGADDSET(p->p_sigignore, i);
392 }
393
394 /*
395 * Reset signals for an exec of the specified process.
396 */
397 void
398 execsigs(struct proc *p)
399 {
400 struct sigacts *ps = p->p_sigacts;
401 struct lwp *lp;
402 int sig;
403
404 lp = ONLY_LWP_IN_PROC(p);
405
406 /*
407 * Reset caught signals. Held signals remain held
408 * through p_sigmask (unless they were caught,
409 * and are now ignored by default).
410 */
411 while (SIGNOTEMPTY(p->p_sigcatch)) {
412 sig = sig_ffs(&p->p_sigcatch);
413 SIGDELSET(p->p_sigcatch, sig);
414 if (sigprop(sig) & SA_IGNORE) {
415 if (sig != SIGCONT)
416 SIGADDSET(p->p_sigignore, sig);
417 SIGDELSET(p->p_siglist, sig);
418 /* don't need spinlock */
419 SIGDELSET(lp->lwp_siglist, sig);
420 }
421 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
422 }
423
424 /*
425 * Reset stack state to the user stack.
426 * Clear set of signals caught on the signal stack.
427 */
428 lp->lwp_sigstk.ss_flags = SS_DISABLE;
429 lp->lwp_sigstk.ss_size = 0;
430 lp->lwp_sigstk.ss_sp = NULL;
431 lp->lwp_flags &= ~LWP_ALTSTACK;
432 /*
433 * Reset no zombies if child dies flag as Solaris does.
434 */
435 p->p_sigacts->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
436 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
437 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
438 }
439
440 /*
441 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc
442 *
443 * Manipulate signal mask. This routine is MP SAFE *ONLY* if
444 * p == curproc.
445 */
446 int
447 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset)
448 {
449 struct thread *td = curthread;
450 struct lwp *lp = td->td_lwp;
451 struct proc *p = td->td_proc;
452 int error;
453
454 lwkt_gettoken(&p->p_token);
455
456 if (oset != NULL)
457 *oset = lp->lwp_sigmask;
458
459 error = 0;
460 if (set != NULL) {
461 switch (how) {
462 case SIG_BLOCK:
463 SIG_CANTMASK(*set);
464 SIGSETOR(lp->lwp_sigmask, *set);
465 break;
466 case SIG_UNBLOCK:
467 SIGSETNAND(lp->lwp_sigmask, *set);
468 break;
469 case SIG_SETMASK:
470 SIG_CANTMASK(*set);
471 lp->lwp_sigmask = *set;
472 break;
473 default:
474 error = EINVAL;
475 break;
476 }
477 }
478
479 lwkt_reltoken(&p->p_token);
480
481 return (error);
482 }
483
484 /*
485 * sigprocmask()
486 *
487 * MPSAFE
488 */
489 int
490 sys_sigprocmask(struct sigprocmask_args *uap)
491 {
492 sigset_t set, oset;
493 sigset_t *setp, *osetp;
494 int error;
495
496 setp = (uap->set != NULL) ? &set : NULL;
497 osetp = (uap->oset != NULL) ? &oset : NULL;
498 if (setp) {
499 error = copyin(uap->set, setp, sizeof(set));
500 if (error)
501 return (error);
502 }
503 error = kern_sigprocmask(uap->how, setp, osetp);
504 if (osetp && !error) {
505 error = copyout(osetp, uap->oset, sizeof(oset));
506 }
507 return (error);
508 }
509
510 /*
511 * MPSAFE
512 */
513 int
514 kern_sigpending(struct __sigset *set)
515 {
516 struct lwp *lp = curthread->td_lwp;
517
518 *set = lwp_sigpend(lp);
519
520 return (0);
521 }
522
523 /*
524 * MPSAFE
525 */
526 int
527 sys_sigpending(struct sigpending_args *uap)
528 {
529 sigset_t set;
530 int error;
531
532 error = kern_sigpending(&set);
533
534 if (error == 0)
535 error = copyout(&set, uap->set, sizeof(set));
536 return (error);
537 }
538
539 /*
540 * Suspend process until signal, providing mask to be set
541 * in the meantime.
542 *
543 * MPSAFE
544 */
545 int
546 kern_sigsuspend(struct __sigset *set)
547 {
548 struct thread *td = curthread;
549 struct lwp *lp = td->td_lwp;
550 struct proc *p = td->td_proc;
551 struct sigacts *ps = p->p_sigacts;
552
553 /*
554 * When returning from sigsuspend, we want
555 * the old mask to be restored after the
556 * signal handler has finished. Thus, we
557 * save it here and mark the sigacts structure
558 * to indicate this.
559 */
560 lp->lwp_oldsigmask = lp->lwp_sigmask;
561 lp->lwp_flags |= LWP_OLDMASK;
562
563 SIG_CANTMASK(*set);
564 lp->lwp_sigmask = *set;
565 while (tsleep(ps, PCATCH, "pause", 0) == 0)
566 /* void */;
567 /* always return EINTR rather than ERESTART... */
568 return (EINTR);
569 }
570
571 /*
572 * Note nonstandard calling convention: libc stub passes mask, not
573 * pointer, to save a copyin.
574 *
575 * MPSAFE
576 */
577 int
578 sys_sigsuspend(struct sigsuspend_args *uap)
579 {
580 sigset_t mask;
581 int error;
582
583 error = copyin(uap->sigmask, &mask, sizeof(mask));
584 if (error)
585 return (error);
586
587 error = kern_sigsuspend(&mask);
588
589 return (error);
590 }
591
592 /*
593 * MPSAFE
594 */
595 int
596 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss)
597 {
598 struct thread *td = curthread;
599 struct lwp *lp = td->td_lwp;
600 struct proc *p = td->td_proc;
601
602 if ((lp->lwp_flags & LWP_ALTSTACK) == 0)
603 lp->lwp_sigstk.ss_flags |= SS_DISABLE;
604
605 if (oss)
606 *oss = lp->lwp_sigstk;
607
608 if (ss) {
609 if (ss->ss_flags & ~SS_DISABLE)
610 return (EINVAL);
611 if (ss->ss_flags & SS_DISABLE) {
612 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK)
613 return (EPERM);
614 lp->lwp_flags &= ~LWP_ALTSTACK;
615 lp->lwp_sigstk.ss_flags = ss->ss_flags;
616 } else {
617 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
618 return (ENOMEM);
619 lp->lwp_flags |= LWP_ALTSTACK;
620 lp->lwp_sigstk = *ss;
621 }
622 }
623
624 return (0);
625 }
626
627 /*
628 * MPSAFE
629 */
630 int
631 sys_sigaltstack(struct sigaltstack_args *uap)
632 {
633 stack_t ss, oss;
634 int error;
635
636 if (uap->ss) {
637 error = copyin(uap->ss, &ss, sizeof(ss));
638 if (error)
639 return (error);
640 }
641
642 error = kern_sigaltstack(uap->ss ? &ss : NULL, uap->oss ? &oss : NULL);
643
644 if (error == 0 && uap->oss)
645 error = copyout(&oss, uap->oss, sizeof(*uap->oss));
646 return (error);
647 }
648
649 /*
650 * Common code for kill process group/broadcast kill.
651 * cp is calling process.
652 */
653 struct killpg_info {
654 int nfound;
655 int sig;
656 };
657
658 static int killpg_all_callback(struct proc *p, void *data);
659
660 static int
661 dokillpg(int sig, int pgid, int all)
662 {
663 struct killpg_info info;
664 struct proc *cp = curproc;
665 struct proc *p;
666 struct pgrp *pgrp;
667
668 info.nfound = 0;
669 info.sig = sig;
670
671 if (all) {
672 /*
673 * broadcast
674 */
675 allproc_scan(killpg_all_callback, &info);
676 } else {
677 if (pgid == 0) {
678 /*
679 * zero pgid means send to my process group.
680 */
681 pgrp = cp->p_pgrp;
682 pgref(pgrp);
683 } else {
684 pgrp = pgfind(pgid);
685 if (pgrp == NULL)
686 return (ESRCH);
687 }
688
689 /*
690 * Must interlock all signals against fork
691 */
692 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
693 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
694 if (p->p_pid <= 1 ||
695 p->p_stat == SZOMB ||
696 (p->p_flags & P_SYSTEM) ||
697 !CANSIGNAL(p, sig)) {
698 continue;
699 }
700 ++info.nfound;
701 if (sig)
702 ksignal(p, sig);
703 }
704 lockmgr(&pgrp->pg_lock, LK_RELEASE);
705 pgrel(pgrp);
706 }
707 return (info.nfound ? 0 : ESRCH);
708 }
709
710 static int
711 killpg_all_callback(struct proc *p, void *data)
712 {
713 struct killpg_info *info = data;
714
715 if (p->p_pid <= 1 || (p->p_flags & P_SYSTEM) ||
716 p == curproc || !CANSIGNAL(p, info->sig)) {
717 return (0);
718 }
719 ++info->nfound;
720 if (info->sig)
721 ksignal(p, info->sig);
722 return(0);
723 }
724
725 /*
726 * Send a general signal to a process or LWPs within that process.
727 *
728 * Note that new signals cannot be sent if a process is exiting or already
729 * a zombie, but we return success anyway as userland is likely to not handle
730 * the race properly.
731 *
732 * No requirements.
733 */
734 int
735 kern_kill(int sig, pid_t pid, lwpid_t tid)
736 {
737 int t;
738
739 if ((u_int)sig > _SIG_MAXSIG)
740 return (EINVAL);
741
742 if (pid > 0) {
743 struct proc *p;
744 struct lwp *lp = NULL;
745
746 /*
747 * Send a signal to a single process. If the kill() is
748 * racing an exiting process which has not yet been reaped
749 * act as though the signal was delivered successfully but
750 * don't actually try to deliver the signal.
751 */
752 if ((p = pfind(pid)) == NULL) {
753 if ((p = zpfind(pid)) == NULL)
754 return (ESRCH);
755 PRELE(p);
756 return (0);
757 }
758 lwkt_gettoken(&p->p_token);
759 if (!CANSIGNAL(p, sig)) {
760 lwkt_reltoken(&p->p_token);
761 PRELE(p);
762 return (EPERM);
763 }
764
765 /*
766 * NOP if the process is exiting. Note that lwpsignal() is
767 * called directly with P_WEXIT set to kill individual LWPs
768 * during exit, which is allowed.
769 */
770 if (p->p_flags & P_WEXIT) {
771 lwkt_reltoken(&p->p_token);
772 PRELE(p);
773 return (0);
774 }
775 if (tid != -1) {
776 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid);
777 if (lp == NULL) {
778 lwkt_reltoken(&p->p_token);
779 PRELE(p);
780 return (ESRCH);
781 }
782 }
783 if (sig)
784 lwpsignal(p, lp, sig);
785 lwkt_reltoken(&p->p_token);
786 PRELE(p);
787
788 return (0);
789 }
790
791 /*
792 * If we come here, pid is a special broadcast pid.
793 * This doesn't mix with a tid.
794 */
795 if (tid != -1)
796 return (EINVAL);
797
798 switch (pid) {
799 case -1: /* broadcast signal */
800 t = (dokillpg(sig, 0, 1));
801 break;
802 case 0: /* signal own process group */
803 t = (dokillpg(sig, 0, 0));
804 break;
805 default: /* negative explicit process group */
806 t = (dokillpg(sig, -pid, 0));
807 break;
808 }
809 return t;
810 }
811
812 int
813 sys_kill(struct kill_args *uap)
814 {
815 int error;
816
817 error = kern_kill(uap->signum, uap->pid, -1);
818 return (error);
819 }
820
821 int
822 sys_lwp_kill(struct lwp_kill_args *uap)
823 {
824 int error;
825 pid_t pid = uap->pid;
826
827 /*
828 * A tid is mandatory for lwp_kill(), otherwise
829 * you could simply use kill().
830 */
831 if (uap->tid == -1)
832 return (EINVAL);
833
834 /*
835 * To save on a getpid() function call for intra-process
836 * signals, pid == -1 means current process.
837 */
838 if (pid == -1)
839 pid = curproc->p_pid;
840
841 error = kern_kill(uap->signum, pid, uap->tid);
842 return (error);
843 }
844
845 /*
846 * Send a signal to a process group.
847 */
848 void
849 gsignal(int pgid, int sig)
850 {
851 struct pgrp *pgrp;
852
853 if (pgid && (pgrp = pgfind(pgid)))
854 pgsignal(pgrp, sig, 0);
855 }
856
857 /*
858 * Send a signal to a process group. If checktty is 1,
859 * limit to members which have a controlling terminal.
860 *
861 * pg_lock interlocks against a fork that might be in progress, to
862 * ensure that the new child process picks up the signal.
863 */
864 void
865 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
866 {
867 struct proc *p;
868
869 /*
870 * Must interlock all signals against fork
871 */
872 if (pgrp) {
873 pgref(pgrp);
874 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
875 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
876 if (checkctty == 0 || p->p_flags & P_CONTROLT)
877 ksignal(p, sig);
878 }
879 lockmgr(&pgrp->pg_lock, LK_RELEASE);
880 pgrel(pgrp);
881 }
882 }
883
884 /*
885 * Send a signal caused by a trap to the current lwp. If it will be caught
886 * immediately, deliver it with correct code. Otherwise, post it normally.
887 *
888 * These signals may ONLY be delivered to the specified lwp and may never
889 * be delivered to the process generically.
890 */
891 void
892 trapsignal(struct lwp *lp, int sig, u_long code)
893 {
894 struct proc *p = lp->lwp_proc;
895 struct sigacts *ps = p->p_sigacts;
896
897 /*
898 * If we are a virtual kernel running an emulated user process
899 * context, switch back to the virtual kernel context before
900 * trying to post the signal.
901 */
902 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
903 struct trapframe *tf = lp->lwp_md.md_regs;
904 tf->tf_trapno = 0;
905 vkernel_trap(lp, tf);
906 }
907
908
909 if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
910 !SIGISMEMBER(lp->lwp_sigmask, sig)) {
911 lp->lwp_ru.ru_nsignals++;
912 #ifdef KTRACE
913 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
914 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)],
915 &lp->lwp_sigmask, code);
916 #endif
917 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
918 &lp->lwp_sigmask, code);
919 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
920 if (!SIGISMEMBER(ps->ps_signodefer, sig))
921 SIGADDSET(lp->lwp_sigmask, sig);
922 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
923 /*
924 * See kern_sigaction() for origin of this code.
925 */
926 SIGDELSET(p->p_sigcatch, sig);
927 if (sig != SIGCONT &&
928 sigprop(sig) & SA_IGNORE)
929 SIGADDSET(p->p_sigignore, sig);
930 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
931 }
932 } else {
933 lp->lwp_code = code; /* XXX for core dump/debugger */
934 lp->lwp_sig = sig; /* XXX to verify code */
935 lwpsignal(p, lp, sig);
936 }
937 }
938
939 /*
940 * Find a suitable lwp to deliver the signal to. Returns NULL if all
941 * lwps hold the signal blocked.
942 *
943 * Caller must hold p->p_token.
944 *
945 * Returns a lp or NULL. If non-NULL the lp is held and its token is
946 * acquired.
947 */
948 static struct lwp *
949 find_lwp_for_signal(struct proc *p, int sig)
950 {
951 struct lwp *lp;
952 struct lwp *run, *sleep, *stop;
953
954 /*
955 * If the running/preempted thread belongs to the proc to which
956 * the signal is being delivered and this thread does not block
957 * the signal, then we can avoid a context switch by delivering
958 * the signal to this thread, because it will return to userland
959 * soon anyways.
960 */
961 lp = lwkt_preempted_proc();
962 if (lp != NULL && lp->lwp_proc == p) {
963 LWPHOLD(lp);
964 lwkt_gettoken(&lp->lwp_token);
965 if (!SIGISMEMBER(lp->lwp_sigmask, sig)) {
966 /* return w/ token held */
967 return (lp);
968 }
969 lwkt_reltoken(&lp->lwp_token);
970 LWPRELE(lp);
971 }
972
973 run = sleep = stop = NULL;
974 FOREACH_LWP_IN_PROC(lp, p) {
975 /*
976 * If the signal is being blocked by the lwp, then this
977 * lwp is not eligible for receiving the signal.
978 */
979 LWPHOLD(lp);
980 lwkt_gettoken(&lp->lwp_token);
981
982 if (SIGISMEMBER(lp->lwp_sigmask, sig)) {
983 lwkt_reltoken(&lp->lwp_token);
984 LWPRELE(lp);
985 continue;
986 }
987
988 switch (lp->lwp_stat) {
989 case LSRUN:
990 if (sleep) {
991 lwkt_token_swap();
992 lwkt_reltoken(&sleep->lwp_token);
993 LWPRELE(sleep);
994 sleep = NULL;
995 run = lp;
996 } else if (stop) {
997 lwkt_token_swap();
998 lwkt_reltoken(&stop->lwp_token);
999 LWPRELE(stop);
1000 stop = NULL;
1001 run = lp;
1002 } else {
1003 run = lp;
1004 }
1005 break;
1006 case LSSLEEP:
1007 if (lp->lwp_flags & LWP_SINTR) {
1008 if (sleep) {
1009 lwkt_reltoken(&lp->lwp_token);
1010 LWPRELE(lp);
1011 } else if (stop) {
1012 lwkt_token_swap();
1013 lwkt_reltoken(&stop->lwp_token);
1014 LWPRELE(stop);
1015 stop = NULL;
1016 sleep = lp;
1017 } else {
1018 sleep = lp;
1019 }
1020 } else {
1021 lwkt_reltoken(&lp->lwp_token);
1022 LWPRELE(lp);
1023 }
1024 break;
1025 case LSSTOP:
1026 if (sleep) {
1027 lwkt_reltoken(&lp->lwp_token);
1028 LWPRELE(lp);
1029 } else if (stop) {
1030 lwkt_reltoken(&lp->lwp_token);
1031 LWPRELE(lp);
1032 } else {
1033 stop = lp;
1034 }
1035 break;
1036 }
1037 if (run)
1038 break;
1039 }
1040
1041 if (run != NULL)
1042 return (run);
1043 else if (sleep != NULL)
1044 return (sleep);
1045 else
1046 return (stop);
1047 }
1048
1049 /*
1050 * Send the signal to the process. If the signal has an action, the action
1051 * is usually performed by the target process rather than the caller; we add
1052 * the signal to the set of pending signals for the process.
1053 *
1054 * Exceptions:
1055 * o When a stop signal is sent to a sleeping process that takes the
1056 * default action, the process is stopped without awakening it.
1057 * o SIGCONT restarts stopped processes (or puts them back to sleep)
1058 * regardless of the signal action (eg, blocked or ignored).
1059 *
1060 * Other ignored signals are discarded immediately.
1061 *
1062 * If the caller wishes to call this function from a hard code section the
1063 * caller must already hold p->p_token (see kern_clock.c).
1064 *
1065 * No requirements.
1066 */
1067 void
1068 ksignal(struct proc *p, int sig)
1069 {
1070 lwpsignal(p, NULL, sig);
1071 }
1072
1073 /*
1074 * The core for ksignal. lp may be NULL, then a suitable thread
1075 * will be chosen. If not, lp MUST be a member of p.
1076 *
1077 * If the caller wishes to call this function from a hard code section the
1078 * caller must already hold p->p_token.
1079 *
1080 * No requirements.
1081 */
1082 void
1083 lwpsignal(struct proc *p, struct lwp *lp, int sig)
1084 {
1085 struct proc *q;
1086 sig_t action;
1087 int prop;
1088
1089 if (sig > _SIG_MAXSIG || sig <= 0) {
1090 kprintf("lwpsignal: signal %d\n", sig);
1091 panic("lwpsignal signal number");
1092 }
1093
1094 KKASSERT(lp == NULL || lp->lwp_proc == p);
1095
1096 /*
1097 * We don't want to race... well, all sorts of things. Get appropriate
1098 * tokens.
1099 *
1100 * Don't try to deliver a generic signal to an exiting process,
1101 * the signal structures could be in flux. We check the LWP later
1102 * on.
1103 */
1104 PHOLD(p);
1105 lwkt_gettoken(&p->p_token);
1106 if (lp) {
1107 LWPHOLD(lp);
1108 lwkt_gettoken(&lp->lwp_token);
1109 } else if (p->p_flags & P_WEXIT) {
1110 goto out;
1111 }
1112
1113 prop = sigprop(sig);
1114
1115 /*
1116 * If proc is traced, always give parent a chance;
1117 * if signal event is tracked by procfs, give *that*
1118 * a chance, as well.
1119 */
1120 if ((p->p_flags & P_TRACED) || (p->p_stops & S_SIG)) {
1121 action = SIG_DFL;
1122 } else {
1123 /*
1124 * Do not try to deliver signals to an exiting lwp other
1125 * than SIGKILL. Note that we must still deliver the signal
1126 * if P_WEXIT is set in the process flags.
1127 */
1128 if (lp && (lp->lwp_mpflags & LWP_MP_WEXIT) && sig != SIGKILL) {
1129 if (lp) {
1130 lwkt_reltoken(&lp->lwp_token);
1131 LWPRELE(lp);
1132 }
1133 lwkt_reltoken(&p->p_token);
1134 PRELE(p);
1135 return;
1136 }
1137
1138 /*
1139 * If the signal is being ignored, then we forget about
1140 * it immediately. NOTE: We don't set SIGCONT in p_sigignore,
1141 * and if it is set to SIG_IGN, action will be SIG_DFL here.
1142 */
1143 if (SIGISMEMBER(p->p_sigignore, sig)) {
1144 /*
1145 * Even if a signal is set SIG_IGN, it may still be
1146 * lurking in a kqueue.
1147 */
1148 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
1149 if (lp) {
1150 lwkt_reltoken(&lp->lwp_token);
1151 LWPRELE(lp);
1152 }
1153 lwkt_reltoken(&p->p_token);
1154 PRELE(p);
1155 return;
1156 }
1157 if (SIGISMEMBER(p->p_sigcatch, sig))
1158 action = SIG_CATCH;
1159 else
1160 action = SIG_DFL;
1161 }
1162
1163 /*
1164 * If continuing, clear any pending STOP signals.
1165 */
1166 if (prop & SA_CONT)
1167 SIG_STOPSIGMASK(p->p_siglist);
1168
1169 if (prop & SA_STOP) {
1170 /*
1171 * If sending a tty stop signal to a member of an orphaned
1172 * process group, discard the signal here if the action
1173 * is default; don't stop the process below if sleeping,
1174 * and don't clear any pending SIGCONT.
1175 */
1176 if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 &&
1177 action == SIG_DFL) {
1178 if (lp) {
1179 lwkt_reltoken(&lp->lwp_token);
1180 LWPRELE(lp);
1181 }
1182 lwkt_reltoken(&p->p_token);
1183 PRELE(p);
1184 return;
1185 }
1186 SIG_CONTSIGMASK(p->p_siglist);
1187 p->p_flags &= ~P_CONTINUED;
1188 }
1189
1190 if (p->p_stat == SSTOP) {
1191 /*
1192 * Nobody can handle this signal, add it to the lwp or
1193 * process pending list
1194 */
1195 if (lp) {
1196 spin_lock(&lp->lwp_spin);
1197 SIGADDSET(lp->lwp_siglist, sig);
1198 spin_unlock(&lp->lwp_spin);
1199 } else {
1200 SIGADDSET(p->p_siglist, sig);
1201 }
1202
1203 /*
1204 * If the process is stopped and is being traced, then no
1205 * further action is necessary.
1206 */
1207 if (p->p_flags & P_TRACED)
1208 goto out;
1209
1210 /*
1211 * If the process is stopped and receives a KILL signal,
1212 * make the process runnable.
1213 */
1214 if (sig == SIGKILL) {
1215 proc_unstop(p, SSTOP);
1216 goto active_process;
1217 }
1218
1219 /*
1220 * If the process is stopped and receives a CONT signal,
1221 * then try to make the process runnable again.
1222 */
1223 if (prop & SA_CONT) {
1224 /*
1225 * If SIGCONT is default (or ignored), we continue the
1226 * process but don't leave the signal in p_siglist, as
1227 * it has no further action. If SIGCONT is held, we
1228 * continue the process and leave the signal in
1229 * p_siglist. If the process catches SIGCONT, let it
1230 * handle the signal itself.
1231 *
1232 * XXX what if the signal is being held blocked?
1233 *
1234 * Token required to interlock kern_wait().
1235 * Reparenting can also cause a race so we have to
1236 * hold (q).
1237 */
1238 q = p->p_pptr;
1239 PHOLD(q);
1240 lwkt_gettoken(&q->p_token);
1241 p->p_flags |= P_CONTINUED;
1242 wakeup(q);
1243 if (action == SIG_DFL)
1244 SIGDELSET(p->p_siglist, sig);
1245 proc_unstop(p, SSTOP);
1246 lwkt_reltoken(&q->p_token);
1247 PRELE(q);
1248 if (action == SIG_CATCH)
1249 goto active_process;
1250 goto out;
1251 }
1252
1253 /*
1254 * If the process is stopped and receives another STOP
1255 * signal, we do not need to stop it again. If we did
1256 * the shell could get confused.
1257 *
1258 * However, if the current/preempted lwp is part of the
1259 * process receiving the signal, we need to keep it,
1260 * so that this lwp can stop in issignal() later, as
1261 * we don't want to wait until it reaches userret!
1262 */
1263 if (prop & SA_STOP) {
1264 if (lwkt_preempted_proc() == NULL ||
1265 lwkt_preempted_proc()->lwp_proc != p)
1266 SIGDELSET(p->p_siglist, sig);
1267 }
1268
1269 /*
1270 * Otherwise the process is stopped and it received some
1271 * signal, which does not change its stopped state. When
1272 * the process is continued a wakeup(p) will be issued which
1273 * will wakeup any threads sleeping in tstop().
1274 */
1275 if (lp == NULL) {
1276 /* NOTE: returns lp w/ token held */
1277 lp = find_lwp_for_signal(p, sig);
1278 }
1279 goto out;
1280
1281 /* NOTREACHED */
1282 }
1283 /* else not stopped */
1284 active_process:
1285
1286 /*
1287 * Never deliver a lwp-specific signal to a random lwp.
1288 */
1289 if (lp == NULL) {
1290 /* NOTE: returns lp w/ token held */
1291 lp = find_lwp_for_signal(p, sig);
1292 if (lp) {
1293 if (SIGISMEMBER(lp->lwp_sigmask, sig)) {
1294 lwkt_reltoken(&lp->lwp_token);
1295 LWPRELE(lp);
1296 lp = NULL;
1297 }
1298 }
1299 }
1300
1301 /*
1302 * Deliver to the process generically if (1) the signal is being
1303 * sent to any thread or (2) we could not find a thread to deliver
1304 * it to.
1305 */
1306 if (lp == NULL) {
1307 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
1308 SIGADDSET(p->p_siglist, sig);
1309 goto out;
1310 }
1311
1312 /*
1313 * Deliver to a specific LWP whether it masks it or not. It will
1314 * not be dispatched if masked but we must still deliver it.
1315 */
1316 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
1317 (p->p_flags & P_TRACED) == 0) {
1318 p->p_nice = NZERO;
1319 }
1320
1321 /*
1322 * If the process receives a STOP signal which indeed needs to
1323 * stop the process, do so. If the process chose to catch the
1324 * signal, it will be treated like any other signal.
1325 */
1326 if ((prop & SA_STOP) && action == SIG_DFL) {
1327 /*
1328 * If a child holding parent blocked, stopping
1329 * could cause deadlock. Take no action at this
1330 * time.
1331 */
1332 if (p->p_flags & P_PPWAIT) {
1333 SIGADDSET(p->p_siglist, sig);
1334 goto out;
1335 }
1336
1337 /*
1338 * Do not actually try to manipulate the process, but simply
1339 * stop it. Lwps will stop as soon as they safely can.
1340 *
1341 * Ignore stop if the process is exiting.
1342 */
1343 if ((p->p_flags & P_WEXIT) == 0) {
1344 p->p_xstat = sig;
1345 proc_stop(p, SSTOP);
1346 }
1347 goto out;
1348 }
1349
1350 /*
1351 * If it is a CONT signal with default action, just ignore it.
1352 */
1353 if ((prop & SA_CONT) && action == SIG_DFL)
1354 goto out;
1355
1356 /*
1357 * Mark signal pending at this specific thread.
1358 */
1359 spin_lock(&lp->lwp_spin);
1360 SIGADDSET(lp->lwp_siglist, sig);
1361 spin_unlock(&lp->lwp_spin);
1362
1363 lwp_signotify(lp);
1364
1365 out:
1366 if (lp) {
1367 lwkt_reltoken(&lp->lwp_token);
1368 LWPRELE(lp);
1369 }
1370 lwkt_reltoken(&p->p_token);
1371 PRELE(p);
1372 }
1373
1374 /*
1375 * Notify the LWP that a signal has arrived. The LWP does not have to be
1376 * sleeping on the current cpu.
1377 *
1378 * p->p_token and lp->lwp_token must be held on call.
1379 *
1380 * We can only safely schedule the thread on its current cpu and only if
1381 * one of the SINTR flags is set. If an SINTR flag is set AND we are on
1382 * the correct cpu we are properly interlocked, otherwise we could be
1383 * racing other thread transition states (or the lwp is on the user scheduler
1384 * runq but not scheduled) and must not do anything.
1385 *
1386 * Since we hold the lwp token we know the lwp cannot be ripped out from
1387 * under us so we can safely hold it to prevent it from being ripped out
1388 * from under us if we are forced to IPI another cpu to make the local
1389 * checks there.
1390 *
1391 * Adjustment of lp->lwp_stat can only occur when we hold the lwp_token,
1392 * which we won't in an IPI so any fixups have to be done here, effectively
1393 * replicating part of what setrunnable() does.
1394 */
1395 static void
1396 lwp_signotify(struct lwp *lp)
1397 {
1398 thread_t dtd;
1399
1400 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_proc->p_token);
1401 dtd = lp->lwp_thread;
1402
1403 crit_enter();
1404 if (lp == lwkt_preempted_proc()) {
1405 /*
1406 * lwp is on the current cpu AND it is currently running
1407 * (we preempted it).
1408 */
1409 signotify();
1410 } else if (lp->lwp_flags & LWP_SINTR) {
1411 /*
1412 * lwp is sitting in tsleep() with PCATCH set
1413 */
1414 if (dtd->td_gd == mycpu) {
1415 setrunnable(lp);
1416 } else {
1417 /*
1418 * We can only adjust lwp_stat while we hold the
1419 * lwp_token, and we won't in the IPI function.
1420 */
1421 LWPHOLD(lp);
1422 if (lp->lwp_stat == LSSTOP)
1423 lp->lwp_stat = LSSLEEP;
1424 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1425 }
1426 } else if (dtd->td_flags & TDF_SINTR) {
1427 /*
1428 * lwp is sitting in lwkt_sleep() with PCATCH set.
1429 */
1430 if (dtd->td_gd == mycpu) {
1431 setrunnable(lp);
1432 } else {
1433 /*
1434 * We can only adjust lwp_stat while we hold the
1435 * lwp_token, and we won't in the IPI function.
1436 */
1437 LWPHOLD(lp);
1438 if (lp->lwp_stat == LSSTOP)
1439 lp->lwp_stat = LSSLEEP;
1440 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1441 }
1442 } else {
1443 /*
1444 * Otherwise the lwp is either in some uninterruptible state
1445 * or it is on the userland scheduler's runqueue waiting to
1446 * be scheduled to a cpu, or it is running in userland. We
1447 * generally want to send an IPI so a running target gets the
1448 * signal ASAP, otherwise a scheduler-tick worth of latency
1449 * will occur.
1450 *
1451 * Issue an IPI to the remote cpu to knock it into the kernel,
1452 * remote cpu will issue the cpu-local signotify() if the IPI
1453 * preempts the desired thread.
1454 */
1455 if (dtd->td_gd != mycpu) {
1456 LWPHOLD(lp);
1457 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1458 }
1459 }
1460 crit_exit();
1461 }
1462
1463 /*
1464 * This function is called via an IPI so we cannot call setrunnable() here
1465 * (because while we hold the lp we don't own its token, and can't get it
1466 * from an IPI).
1467 *
1468 * We are interlocked by virtue of being on the same cpu as the target. If
1469 * we still are and LWP_SINTR or TDF_SINTR is set we can safely schedule
1470 * the target thread.
1471 */
1472 static void
1473 lwp_signotify_remote(void *arg)
1474 {
1475 struct lwp *lp = arg;
1476 thread_t td = lp->lwp_thread;
1477
1478 if (lp == lwkt_preempted_proc()) {
1479 signotify();
1480 LWPRELE(lp);
1481 } else if (td->td_gd == mycpu) {
1482 if ((lp->lwp_flags & LWP_SINTR) ||
1483 (td->td_flags & TDF_SINTR)) {
1484 lwkt_schedule(td);
1485 }
1486 LWPRELE(lp);
1487 } else {
1488 lwkt_send_ipiq(td->td_gd, lwp_signotify_remote, lp);
1489 /* LWPHOLD() is forwarded to the target cpu */
1490 }
1491 }
1492
1493 /*
1494 * Caller must hold p->p_token
1495 */
1496 void
1497 proc_stop(struct proc *p, int sig)
1498 {
1499 struct proc *q;
1500 struct lwp *lp;
1501
1502 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
1503
1504 /*
1505 * If somebody raced us, be happy with it. SCORE overrides SSTOP.
1506 */
1507 if (sig == SCORE) {
1508 if (p->p_stat == SCORE || p->p_stat == SZOMB)
1509 return;
1510 } else {
1511 if (p->p_stat == SSTOP || p->p_stat == SCORE ||
1512 p->p_stat == SZOMB) {
1513 return;
1514 }
1515 }
1516 p->p_stat = sig;
1517
1518 FOREACH_LWP_IN_PROC(lp, p) {
1519 LWPHOLD(lp);
1520 lwkt_gettoken(&lp->lwp_token);
1521
1522 switch (lp->lwp_stat) {
1523 case LSSTOP:
1524 /*
1525 * Do nothing, we are already counted in
1526 * p_nstopped.
1527 */
1528 break;
1529
1530 case LSSLEEP:
1531 /*
1532 * We're sleeping, but we will stop before
1533 * returning to userspace, so count us
1534 * as stopped as well. We set LWP_MP_WSTOP
1535 * to signal the lwp that it should not
1536 * increase p_nstopped when reaching tstop().
1537 *
1538 * LWP_MP_WSTOP is protected by lp->lwp_token.
1539 */
1540 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) {
1541 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP);
1542 ++p->p_nstopped;
1543 }
1544 break;
1545
1546 case LSRUN:
1547 /*
1548 * We might notify ourself, but that's not
1549 * a problem.
1550 */
1551 lwp_signotify(lp);
1552 break;
1553 }
1554 lwkt_reltoken(&lp->lwp_token);
1555 LWPRELE(lp);
1556 }
1557
1558 if (p->p_nstopped == p->p_nthreads) {
1559 /*
1560 * Token required to interlock kern_wait(). Reparenting can
1561 * also cause a race so we have to hold (q).
1562 */
1563 q = p->p_pptr;
1564 PHOLD(q);
1565 lwkt_gettoken(&q->p_token);
1566 p->p_flags &= ~P_WAITED;
1567 wakeup(q);
1568 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1569 ksignal(p->p_pptr, SIGCHLD);
1570 lwkt_reltoken(&q->p_token);
1571 PRELE(q);
1572 }
1573 }
1574
1575 /*
1576 * Caller must hold p_token
1577 */
1578 void
1579 proc_unstop(struct proc *p, int sig)
1580 {
1581 struct lwp *lp;
1582
1583 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
1584
1585 if (p->p_stat != sig)
1586 return;
1587
1588 p->p_stat = SACTIVE;
1589
1590 FOREACH_LWP_IN_PROC(lp, p) {
1591 LWPHOLD(lp);
1592 lwkt_gettoken(&lp->lwp_token);
1593
1594 switch (lp->lwp_stat) {
1595 case LSRUN:
1596 /*
1597 * Uh? Not stopped? Well, I guess that's okay.
1598 */
1599 if (bootverbose)
1600 kprintf("proc_unstop: lwp %d/%d not sleeping\n",
1601 p->p_pid, lp->lwp_tid);
1602 break;
1603
1604 case LSSLEEP:
1605 /*
1606 * Still sleeping. Don't bother waking it up.
1607 * However, if this thread was counted as
1608 * stopped, undo this.
1609 *
1610 * Nevertheless we call setrunnable() so that it
1611 * will wake up in case a signal or timeout arrived
1612 * in the meantime.
1613 *
1614 * LWP_MP_WSTOP is protected by lp->lwp_token.
1615 */
1616 if (lp->lwp_mpflags & LWP_MP_WSTOP) {
1617 atomic_clear_int(&lp->lwp_mpflags,
1618 LWP_MP_WSTOP);
1619 --p->p_nstopped;
1620 } else {
1621 if (bootverbose)
1622 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n",
1623 p->p_pid, lp->lwp_tid);
1624 }
1625 /* FALLTHROUGH */
1626
1627 case LSSTOP:
1628 /*
1629 * This handles any lwp's waiting in a tsleep with
1630 * SIGCATCH.
1631 */
1632 lwp_signotify(lp);
1633 break;
1634
1635 }
1636 lwkt_reltoken(&lp->lwp_token);
1637 LWPRELE(lp);
1638 }
1639
1640 /*
1641 * This handles any lwp's waiting in tstop(). We have interlocked
1642 * the setting of p_stat by acquiring and releasing each lpw's
1643 * token.
1644 */
1645 wakeup(p);
1646 }
1647
1648 /*
1649 * Wait for all threads except the current thread to stop.
1650 */
1651 static void
1652 proc_stopwait(struct proc *p)
1653 {
1654 while ((p->p_stat == SSTOP || p->p_stat == SCORE) &&
1655 p->p_nstopped < p->p_nthreads - 1) {
1656 tsleep_interlock(&p->p_nstopped, 0);
1657 if (p->p_nstopped < p->p_nthreads - 1) {
1658 tsleep(&p->p_nstopped, PINTERLOCKED, "stopwt", hz);
1659 }
1660 }
1661 }
1662
1663 /*
1664 * No requirements.
1665 */
1666 static int
1667 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1668 {
1669 sigset_t savedmask, set;
1670 struct proc *p = curproc;
1671 struct lwp *lp = curthread->td_lwp;
1672 int error, sig, hz, timevalid = 0;
1673 struct timespec rts, ets, ts;
1674 struct timeval tv;
1675
1676 error = 0;
1677 sig = 0;
1678 ets.tv_sec = 0; /* silence compiler warning */
1679 ets.tv_nsec = 0; /* silence compiler warning */
1680 SIG_CANTMASK(waitset);
1681 savedmask = lp->lwp_sigmask;
1682
1683 if (timeout) {
1684 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1685 timeout->tv_nsec < 1000000000) {
1686 timevalid = 1;
1687 getnanouptime(&rts);
1688 ets = rts;
1689 timespecadd(&ets, timeout);
1690 }
1691 }
1692
1693 for (;;) {
1694 set = lwp_sigpend(lp);
1695 SIGSETAND(set, waitset);
1696 if ((sig = sig_ffs(&set)) != 0) {
1697 SIGFILLSET(lp->lwp_sigmask);
1698 SIGDELSET(lp->lwp_sigmask, sig);
1699 SIG_CANTMASK(lp->lwp_sigmask);
1700 sig = issignal(lp, 1);
1701 /*
1702 * It may be a STOP signal, in the case, issignal
1703 * returns 0, because we may stop there, and new
1704 * signal can come in, we should restart if we got
1705 * nothing.
1706 */
1707 if (sig == 0)
1708 continue;
1709 else
1710 break;
1711 }
1712
1713 /*
1714 * Previous checking got nothing, and we retried but still
1715 * got nothing, we should return the error status.
1716 */
1717 if (error)
1718 break;
1719
1720 /*
1721 * POSIX says this must be checked after looking for pending
1722 * signals.
1723 */
1724 if (timeout) {
1725 if (timevalid == 0) {
1726 error = EINVAL;
1727 break;
1728 }
1729 getnanouptime(&rts);
1730 if (timespeccmp(&rts, &ets, >=)) {
1731 error = EAGAIN;
1732 break;
1733 }
1734 ts = ets;
1735 timespecsub(&ts, &rts);
1736 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1737 hz = tvtohz_high(&tv);
1738 } else {
1739 hz = 0;
1740 }
1741
1742 lp->lwp_sigmask = savedmask;
1743 SIGSETNAND(lp->lwp_sigmask, waitset);
1744 /*
1745 * We won't ever be woken up. Instead, our sleep will
1746 * be broken in lwpsignal().
1747 */
1748 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1749 if (timeout) {
1750 if (error == ERESTART) {
1751 /* can not restart a timeout wait. */
1752 error = EINTR;
1753 } else if (error == EAGAIN) {
1754 /* will calculate timeout by ourself. */
1755 error = 0;
1756 }
1757 }
1758 /* Retry ... */
1759 }
1760
1761 lp->lwp_sigmask = savedmask;
1762 if (sig) {
1763 error = 0;
1764 bzero(info, sizeof(*info));
1765 info->si_signo = sig;
1766 spin_lock(&lp->lwp_spin);
1767 lwp_delsig(lp, sig); /* take the signal! */
1768 spin_unlock(&lp->lwp_spin);
1769
1770 if (sig == SIGKILL) {
1771 sigexit(lp, sig);
1772 /* NOT REACHED */
1773 }
1774 }
1775
1776 return (error);
1777 }
1778
1779 /*
1780 * MPALMOSTSAFE
1781 */
1782 int
1783 sys_sigtimedwait(struct sigtimedwait_args *uap)
1784 {
1785 struct timespec ts;
1786 struct timespec *timeout;
1787 sigset_t set;
1788 siginfo_t info;
1789 int error;
1790
1791 if (uap->timeout) {
1792 error = copyin(uap->timeout, &ts, sizeof(ts));
1793 if (error)
1794 return (error);
1795 timeout = &ts;
1796 } else {
1797 timeout = NULL;
1798 }
1799 error = copyin(uap->set, &set, sizeof(set));
1800 if (error)
1801 return (error);
1802 error = kern_sigtimedwait(set, &info, timeout);
1803 if (error)
1804 return (error);
1805 if (uap->info)
1806 error = copyout(&info, uap->info, sizeof(info));
1807 /* Repost if we got an error. */
1808 /*
1809 * XXX lwp
1810 *
1811 * This could transform a thread-specific signal to another
1812 * thread / process pending signal.
1813 */
1814 if (error) {
1815 ksignal(curproc, info.si_signo);
1816 } else {
1817 uap->sysmsg_result = info.si_signo;
1818 }
1819 return (error);
1820 }
1821
1822 /*
1823 * MPALMOSTSAFE
1824 */
1825 int
1826 sys_sigwaitinfo(struct sigwaitinfo_args *uap)
1827 {
1828 siginfo_t info;
1829 sigset_t set;
1830 int error;
1831
1832 error = copyin(uap->set, &set, sizeof(set));
1833 if (error)
1834 return (error);
1835 error = kern_sigtimedwait(set, &info, NULL);
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 * If the current process has received a signal that would interrupt a
1857 * system call, return EINTR or ERESTART as appropriate.
1858 */
1859 int
1860 iscaught(struct lwp *lp)
1861 {
1862 struct proc *p = lp->lwp_proc;
1863 int sig;
1864
1865 if (p) {
1866 if ((sig = CURSIG(lp)) != 0) {
1867 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1868 return (EINTR);
1869 return (ERESTART);
1870 }
1871 }
1872 return(EWOULDBLOCK);
1873 }
1874
1875 /*
1876 * If the current process has received a signal (should be caught or cause
1877 * termination, should interrupt current syscall), return the signal number.
1878 * Stop signals with default action are processed immediately, then cleared;
1879 * they aren't returned. This is checked after each entry to the system for
1880 * a syscall or trap (though this can usually be done without calling issignal
1881 * by checking the pending signal masks in the CURSIG macro).
1882 *
1883 * This routine is called via CURSIG/__cursig. We will acquire and release
1884 * p->p_token but if the caller needs to interlock the test the caller must
1885 * also hold p->p_token.
1886 *
1887 * while (sig = CURSIG(curproc))
1888 * postsig(sig);
1889 *
1890 * MPSAFE
1891 */
1892 int
1893 issignal(struct lwp *lp, int maytrace)
1894 {
1895 struct proc *p = lp->lwp_proc;
1896 sigset_t mask;
1897 int sig, prop;
1898
1899 lwkt_gettoken(&p->p_token);
1900
1901 for (;;) {
1902 int traced = (p->p_flags & P_TRACED) || (p->p_stops & S_SIG);
1903
1904 /*
1905 * If this process is supposed to stop, stop this thread.
1906 */
1907 if (STOPLWP(p, lp))
1908 tstop();
1909
1910 mask = lwp_sigpend(lp);
1911 SIGSETNAND(mask, lp->lwp_sigmask);
1912 if (p->p_flags & P_PPWAIT)
1913 SIG_STOPSIGMASK(mask);
1914 if (SIGISEMPTY(mask)) { /* no signal to send */
1915 lwkt_reltoken(&p->p_token);
1916 return (0);
1917 }
1918 sig = sig_ffs(&mask);
1919
1920 STOPEVENT(p, S_SIG, sig);
1921
1922 /*
1923 * We should see pending but ignored signals
1924 * only if P_TRACED was on when they were posted.
1925 */
1926 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
1927 spin_lock(&lp->lwp_spin);
1928 lwp_delsig(lp, sig);
1929 spin_unlock(&lp->lwp_spin);
1930 continue;
1931 }
1932 if (maytrace &&
1933 (p->p_flags & P_TRACED) &&
1934 (p->p_flags & P_PPWAIT) == 0) {
1935 /*
1936 * If traced, always stop, and stay stopped until
1937 * released by the parent.
1938 *
1939 * NOTE: SSTOP may get cleared during the loop,
1940 * but we do not re-notify the parent if we have
1941 * to loop several times waiting for the parent
1942 * to let us continue.
1943 *
1944 * XXX not sure if this is still true
1945 */
1946 p->p_xstat = sig;
1947 proc_stop(p, SSTOP);
1948 do {
1949 tstop();
1950 } while (!trace_req(p) && (p->p_flags & P_TRACED));
1951
1952 /*
1953 * If parent wants us to take the signal,
1954 * then it will leave it in p->p_xstat;
1955 * otherwise we just look for signals again.
1956 */
1957 spin_lock(&lp->lwp_spin);
1958 lwp_delsig(lp, sig); /* clear old signal */
1959 spin_unlock(&lp->lwp_spin);
1960 sig = p->p_xstat;
1961 if (sig == 0)
1962 continue;
1963
1964 /*
1965 * Put the new signal into p_siglist. If the
1966 * signal is being masked, look for other signals.
1967 *
1968 * XXX lwp might need a call to ksignal()
1969 */
1970 SIGADDSET(p->p_siglist, sig);
1971 if (SIGISMEMBER(lp->lwp_sigmask, sig))
1972 continue;
1973
1974 /*
1975 * If the traced bit got turned off, go back up
1976 * to the top to rescan signals. This ensures
1977 * that p_sig* and ps_sigact are consistent.
1978 */
1979 if ((p->p_flags & P_TRACED) == 0)
1980 continue;
1981 }
1982
1983 prop = sigprop(sig);
1984
1985 /*
1986 * Decide whether the signal should be returned.
1987 * Return the signal's number, or fall through
1988 * to clear it from the pending mask.
1989 */
1990 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
1991 case (intptr_t)SIG_DFL:
1992 /*
1993 * Don't take default actions on system processes.
1994 */
1995 if (p->p_pid <= 1) {
1996 #ifdef DIAGNOSTIC
1997 /*
1998 * Are you sure you want to ignore SIGSEGV
1999 * in init? XXX
2000 */
2001 kprintf("Process (pid %lu) got signal %d\n",
2002 (u_long)p->p_pid, sig);
2003 #endif
2004 break; /* == ignore */
2005 }
2006
2007 /*
2008 * Handle the in-kernel checkpoint action
2009 */
2010 if (prop & SA_CKPT) {
2011 checkpoint_signal_handler(lp);
2012 break;
2013 }
2014
2015 /*
2016 * If there is a pending stop signal to process
2017 * with default action, stop here,
2018 * then clear the signal. However,
2019 * if process is member of an orphaned
2020 * process group, ignore tty stop signals.
2021 */
2022 if (prop & SA_STOP) {
2023 if (p->p_flags & P_TRACED ||
2024 (p->p_pgrp->pg_jobc == 0 &&
2025 prop & SA_TTYSTOP))
2026 break; /* == ignore */
2027 if ((p->p_flags & P_WEXIT) == 0) {
2028 p->p_xstat = sig;
2029 proc_stop(p, SSTOP);
2030 tstop();
2031 }
2032 break;
2033 } else if (prop & SA_IGNORE) {
2034 /*
2035 * Except for SIGCONT, shouldn't get here.
2036 * Default action is to ignore; drop it.
2037 */
2038 break; /* == ignore */
2039 } else {
2040 lwkt_reltoken(&p->p_token);
2041 return (sig);
2042 }
2043
2044 /*NOTREACHED*/
2045
2046 case (intptr_t)SIG_IGN:
2047 /*
2048 * Masking above should prevent us ever trying
2049 * to take action on an ignored signal other
2050 * than SIGCONT, unless process is traced.
2051 */
2052 if ((prop & SA_CONT) == 0 &&
2053 (p->p_flags & P_TRACED) == 0)
2054 kprintf("issignal\n");
2055 break; /* == ignore */
2056
2057 default:
2058 /*
2059 * This signal has an action, let
2060 * postsig() process it.
2061 */
2062 lwkt_reltoken(&p->p_token);
2063 return (sig);
2064 }
2065 spin_lock(&lp->lwp_spin);
2066 lwp_delsig(lp, sig); /* take the signal! */
2067 spin_unlock(&lp->lwp_spin);
2068 }
2069 /* NOTREACHED */
2070 }
2071
2072 /*
2073 * Take the action for the specified signal
2074 * from the current set of pending signals.
2075 *
2076 * Caller must hold p->p_token
2077 */
2078 void
2079 postsig(int sig)
2080 {
2081 struct lwp *lp = curthread->td_lwp;
2082 struct proc *p = lp->lwp_proc;
2083 struct sigacts *ps = p->p_sigacts;
2084 sig_t action;
2085 sigset_t returnmask;
2086 int code;
2087
2088 KASSERT(sig != 0, ("postsig"));
2089
2090 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
2091
2092 /*
2093 * If we are a virtual kernel running an emulated user process
2094 * context, switch back to the virtual kernel context before
2095 * trying to post the signal.
2096 */
2097 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
2098 struct trapframe *tf = lp->lwp_md.md_regs;
2099 tf->tf_trapno = 0;
2100 vkernel_trap(lp, tf);
2101 }
2102
2103 spin_lock(&lp->lwp_spin);
2104 lwp_delsig(lp, sig);
2105 spin_unlock(&lp->lwp_spin);
2106 action = ps->ps_sigact[_SIG_IDX(sig)];
2107 #ifdef KTRACE
2108 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
2109 ktrpsig(lp, sig, action, lp->lwp_flags & LWP_OLDMASK ?
2110 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0);
2111 #endif
2112 STOPEVENT(p, S_SIG, sig);
2113
2114 if (action == SIG_DFL) {
2115 /*
2116 * Default action, where the default is to kill
2117 * the process. (Other cases were ignored above.)
2118 */
2119 sigexit(lp, sig);
2120 /* NOTREACHED */
2121 } else {
2122 /*
2123 * If we get here, the signal must be caught.
2124 */
2125 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig),
2126 ("postsig action"));
2127
2128 /*
2129 * Reset the signal handler if asked to
2130 */
2131 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
2132 /*
2133 * See kern_sigaction() for origin of this code.
2134 */
2135 SIGDELSET(p->p_sigcatch, sig);
2136 if (sig != SIGCONT &&
2137 sigprop(sig) & SA_IGNORE)
2138 SIGADDSET(p->p_sigignore, sig);
2139 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
2140 }
2141
2142 /*
2143 * Set the signal mask and calculate the mask to restore
2144 * when the signal function returns.
2145 *
2146 * Special case: user has done a sigsuspend. Here the
2147 * current mask is not of interest, but rather the
2148 * mask from before the sigsuspend is what we want
2149 * restored after the signal processing is completed.
2150 */
2151 if (lp->lwp_flags & LWP_OLDMASK) {
2152 returnmask = lp->lwp_oldsigmask;
2153 lp->lwp_flags &= ~LWP_OLDMASK;
2154 } else {
2155 returnmask = lp->lwp_sigmask;
2156 }
2157
2158 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
2159 if (!SIGISMEMBER(ps->ps_signodefer, sig))
2160 SIGADDSET(lp->lwp_sigmask, sig);
2161
2162 lp->lwp_ru.ru_nsignals++;
2163 if (lp->lwp_sig != sig) {
2164 code = 0;
2165 } else {
2166 code = lp->lwp_code;
2167 lp->lwp_code = 0;
2168 lp->lwp_sig = 0;
2169 }
2170 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
2171 }
2172 }
2173
2174 /*
2175 * Kill the current process for stated reason.
2176 */
2177 void
2178 killproc(struct proc *p, char *why)
2179 {
2180 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n",
2181 p->p_pid, p->p_comm,
2182 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
2183 ksignal(p, SIGKILL);
2184 }
2185
2186 /*
2187 * Force the current process to exit with the specified signal, dumping core
2188 * if appropriate. We bypass the normal tests for masked and caught signals,
2189 * allowing unrecoverable failures to terminate the process without changing
2190 * signal state. Mark the accounting record with the signal termination.
2191 * If dumping core, save the signal number for the debugger. Calls exit and
2192 * does not return.
2193 *
2194 * This routine does not return.
2195 */
2196 void
2197 sigexit(struct lwp *lp, int sig)
2198 {
2199 struct proc *p = lp->lwp_proc;
2200
2201 lwkt_gettoken(&p->p_token);
2202 p->p_acflag |= AXSIG;
2203 if (sigprop(sig) & SA_CORE) {
2204 lp->lwp_sig = sig;
2205
2206 /*
2207 * All threads must be stopped before we can safely coredump.
2208 * Stop threads using SCORE, which cannot be overridden.
2209 */
2210 if (p->p_stat != SCORE) {
2211 proc_stop(p, SCORE);
2212 proc_stopwait(p);
2213
2214 if (coredump(lp, sig) == 0)
2215 sig |= WCOREFLAG;
2216 p->p_stat = SSTOP;
2217 }
2218
2219 /*
2220 * Log signals which would cause core dumps
2221 * (Log as LOG_INFO to appease those who don't want
2222 * these messages.)
2223 * XXX : Todo, as well as euid, write out ruid too
2224 */
2225 if (kern_logsigexit)
2226 log(LOG_INFO,
2227 "pid %d (%s), uid %d: exited on signal %d%s\n",
2228 p->p_pid, p->p_comm,
2229 p->p_ucred ? p->p_ucred->cr_uid : -1,
2230 sig &~ WCOREFLAG,
2231 sig & WCOREFLAG ? " (core dumped)" : "");
2232 }
2233 lwkt_reltoken(&p->p_token);
2234 exit1(W_EXITCODE(0, sig));
2235 /* NOTREACHED */
2236 }
2237
2238 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
2239 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
2240 sizeof(corefilename), "process corefile name format string");
2241
2242 /*
2243 * expand_name(name, uid, pid)
2244 * Expand the name described in corefilename, using name, uid, and pid.
2245 * corefilename is a kprintf-like string, with three format specifiers:
2246 * %N name of process ("name")
2247 * %P process id (pid)
2248 * %U user id (uid)
2249 * For example, "%N.core" is the default; they can be disabled completely
2250 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
2251 * This is controlled by the sysctl variable kern.corefile (see above).
2252 */
2253
2254 static char *
2255 expand_name(const char *name, uid_t uid, pid_t pid)
2256 {
2257 char *temp;
2258 char buf[11]; /* Buffer for pid/uid -- max 4B */
2259 int i, n;
2260 char *format = corefilename;
2261 size_t namelen;
2262
2263 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
2264 if (temp == NULL)
2265 return NULL;
2266 namelen = strlen(name);
2267 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
2268 int l;
2269 switch (format[i]) {
2270 case '%': /* Format character */
2271 i++;
2272 switch (format[i]) {
2273 case '%':
2274 temp[n++] = '%';
2275 break;
2276 case 'N': /* process name */
2277 if ((n + namelen) > MAXPATHLEN) {
2278 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2279 pid, name, uid, temp, name);
2280 kfree(temp, M_TEMP);
2281 return NULL;
2282 }
2283 memcpy(temp+n, name, namelen);
2284 n += namelen;
2285 break;
2286 case 'P': /* process id */
2287 l = ksprintf(buf, "%u", pid);
2288 if ((n + l) > MAXPATHLEN) {
2289 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2290 pid, name, uid, temp, name);
2291 kfree(temp, M_TEMP);
2292 return NULL;
2293 }
2294 memcpy(temp+n, buf, l);
2295 n += l;
2296 break;
2297 case 'U': /* user id */
2298 l = ksprintf(buf, "%u", uid);
2299 if ((n + l) > MAXPATHLEN) {
2300 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2301 pid, name, uid, temp, name);
2302 kfree(temp, M_TEMP);
2303 return NULL;
2304 }
2305 memcpy(temp+n, buf, l);
2306 n += l;
2307 break;
2308 default:
2309 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
2310 }
2311 break;
2312 default:
2313 temp[n++] = format[i];
2314 }
2315 }
2316 temp[n] = '\0';
2317 return temp;
2318 }
2319
2320 /*
2321 * Dump a process' core. The main routine does some
2322 * policy checking, and creates the name of the coredump;
2323 * then it passes on a vnode and a size limit to the process-specific
2324 * coredump routine if there is one; if there _is not_ one, it returns
2325 * ENOSYS; otherwise it returns the error from the process-specific routine.
2326 *
2327 * The parameter `lp' is the lwp which triggered the coredump.
2328 */
2329
2330 static int
2331 coredump(struct lwp *lp, int sig)
2332 {
2333 struct proc *p = lp->lwp_proc;
2334 struct vnode *vp;
2335 struct ucred *cred = p->p_ucred;
2336 struct flock lf;
2337 struct nlookupdata nd;
2338 struct vattr vattr;
2339 int error, error1;
2340 char *name; /* name of corefile */
2341 off_t limit;
2342
2343 STOPEVENT(p, S_CORE, 0);
2344
2345 if (((sugid_coredump == 0) && p->p_flags & P_SUGID) || do_coredump == 0)
2346 return (EFAULT);
2347
2348 /*
2349 * Note that the bulk of limit checking is done after
2350 * the corefile is created. The exception is if the limit
2351 * for corefiles is 0, in which case we don't bother
2352 * creating the corefile at all. This layout means that
2353 * a corefile is truncated instead of not being created,
2354 * if it is larger than the limit.
2355 */
2356 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
2357 if (limit == 0)
2358 return EFBIG;
2359
2360 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
2361 if (name == NULL)
2362 return (EINVAL);
2363 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
2364 if (error == 0)
2365 error = vn_open(&nd, NULL,
2366 O_CREAT | FWRITE | O_NOFOLLOW,
2367 S_IRUSR | S_IWUSR);
2368 kfree(name, M_TEMP);
2369 if (error) {
2370 nlookup_done(&nd);
2371 return (error);
2372 }
2373 vp = nd.nl_open_vp;
2374 nd.nl_open_vp = NULL;
2375 nlookup_done(&nd);
2376
2377 vn_unlock(vp);
2378 lf.l_whence = SEEK_SET;
2379 lf.l_start = 0;
2380 lf.l_len = 0;
2381 lf.l_type = F_WRLCK;
2382 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
2383 if (error)
2384 goto out2;
2385
2386 /* Don't dump to non-regular files or files with links. */
2387 if (vp->v_type != VREG ||
2388 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
2389 error = EFAULT;
2390 goto out1;
2391 }
2392
2393 /* Don't dump to files current user does not own */
2394 if (vattr.va_uid != p->p_ucred->cr_uid) {
2395 error = EFAULT;
2396 goto out1;
2397 }
2398
2399 VATTR_NULL(&vattr);
2400 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2401 vattr.va_size = 0;
2402 VOP_SETATTR(vp, &vattr, cred);
2403 p->p_acflag |= ACORE;
2404 vn_unlock(vp);
2405
2406 error = p->p_sysent->sv_coredump ?
2407 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS;
2408
2409 out1:
2410 lf.l_type = F_UNLCK;
2411 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
2412 out2:
2413 error1 = vn_close(vp, FWRITE, NULL);
2414 if (error == 0)
2415 error = error1;
2416 return (error);
2417 }
2418
2419 /*
2420 * Nonexistent system call-- signal process (may want to handle it).
2421 * Flag error in case process won't see signal immediately (blocked or ignored).
2422 *
2423 * MPALMOSTSAFE
2424 */
2425 /* ARGSUSED */
2426 int
2427 sys_nosys(struct nosys_args *args)
2428 {
2429 lwpsignal(curproc, curthread->td_lwp, SIGSYS);
2430 return (EINVAL);
2431 }
2432
2433 /*
2434 * Send a SIGIO or SIGURG signal to a process or process group using
2435 * stored credentials rather than those of the current process.
2436 */
2437 void
2438 pgsigio(struct sigio *sigio, int sig, int checkctty)
2439 {
2440 if (sigio == NULL)
2441 return;
2442
2443 if (sigio->sio_pgid > 0) {
2444 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
2445 sigio->sio_proc))
2446 ksignal(sigio->sio_proc, sig);
2447 } else if (sigio->sio_pgid < 0) {
2448 struct proc *p;
2449 struct pgrp *pg = sigio->sio_pgrp;
2450
2451 /*
2452 * Must interlock all signals against fork
2453 */
2454 pgref(pg);
2455 lockmgr(&pg->pg_lock, LK_EXCLUSIVE);
2456 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
2457 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
2458 (checkctty == 0 || (p->p_flags & P_CONTROLT)))
2459 ksignal(p, sig);
2460 }
2461 lockmgr(&pg->pg_lock, LK_RELEASE);
2462 pgrel(pg);
2463 }
2464 }
2465
2466 static int
2467 filt_sigattach(struct knote *kn)
2468 {
2469 struct proc *p = curproc;
2470
2471 kn->kn_ptr.p_proc = p;
2472 kn->kn_flags |= EV_CLEAR; /* automatically set */
2473
2474 /* XXX lock the proc here while adding to the list? */
2475 knote_insert(&p->p_klist, kn);
2476
2477 return (0);
2478 }
2479
2480 static void
2481 filt_sigdetach(struct knote *kn)
2482 {
2483 struct proc *p = kn->kn_ptr.p_proc;
2484
2485 knote_remove(&p->p_klist, kn);
2486 }
2487
2488 /*
2489 * signal knotes are shared with proc knotes, so we apply a mask to
2490 * the hint in order to differentiate them from process hints. This
2491 * could be avoided by using a signal-specific knote list, but probably
2492 * isn't worth the trouble.
2493 */
2494 static int
2495 filt_signal(struct knote *kn, long hint)
2496 {
2497 if (hint & NOTE_SIGNAL) {
2498 hint &= ~NOTE_SIGNAL;
2499
2500 if (kn->kn_id == hint)
2501 kn->kn_data++;
2502 }
2503 return (kn->kn_data != 0);
2504 }
DragonFly BSD