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kernel/libc: Remove sigstack() remains.
[dragonfly.git] / sys / kern / kern_sig.c
blobff59d8eb0e6f9d7d8b1275270378f103d70dda8f
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 * Allows us to populate siginfo->si_pid and si_uid in the target process
229 * (p) from the originating thread (td). This function must work properly
230 * even if a kernel thread is sending the signal.
231 *
232 * NOTE: Signals are not queued, so if multiple signals are received the
233 * signal handler will only see the most recent pid and uid for any
234 * given signal number.
235 */
236 static __inline void
237 sigsetfrompid(thread_t td, struct proc *p, int sig)
238 {
239 struct sigacts *sap;
240
241 if ((sap = p->p_sigacts) == NULL)
242 return;
243 if (td->td_proc) {
244 sap->ps_frominfo[sig].pid = td->td_proc->p_pid;
245 sap->ps_frominfo[sig].uid = td->td_ucred->cr_uid;
246 } else {
247 sap->ps_frominfo[sig].pid = 0;
248 sap->ps_frominfo[sig].uid = 0;
249 }
250 }
251
252 /*
253 * No requirements.
254 */
255 int
256 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact)
257 {
258 struct thread *td = curthread;
259 struct proc *p = td->td_proc;
260 struct lwp *lp;
261 struct sigacts *ps = p->p_sigacts;
262
263 if (sig <= 0 || sig > _SIG_MAXSIG)
264 return (EINVAL);
265
266 lwkt_gettoken(&p->p_token);
267
268 if (oact) {
269 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
270 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
271 oact->sa_flags = 0;
272 if (SIGISMEMBER(ps->ps_sigonstack, sig))
273 oact->sa_flags |= SA_ONSTACK;
274 if (!SIGISMEMBER(ps->ps_sigintr, sig))
275 oact->sa_flags |= SA_RESTART;
276 if (SIGISMEMBER(ps->ps_sigreset, sig))
277 oact->sa_flags |= SA_RESETHAND;
278 if (SIGISMEMBER(ps->ps_signodefer, sig))
279 oact->sa_flags |= SA_NODEFER;
280 if (SIGISMEMBER(ps->ps_siginfo, sig))
281 oact->sa_flags |= SA_SIGINFO;
282 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP)
283 oact->sa_flags |= SA_NOCLDSTOP;
284 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT)
285 oact->sa_flags |= SA_NOCLDWAIT;
286 }
287 if (act) {
288 /*
289 * Check for invalid requests. KILL and STOP cannot be
290 * caught.
291 */
292 if (sig == SIGKILL || sig == SIGSTOP) {
293 if (act->sa_handler != SIG_DFL) {
294 lwkt_reltoken(&p->p_token);
295 return (EINVAL);
296 }
297 }
298
299 /*
300 * Change setting atomically.
301 */
302 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
303 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
304 if (act->sa_flags & SA_SIGINFO) {
305 ps->ps_sigact[_SIG_IDX(sig)] =
306 (__sighandler_t *)act->sa_sigaction;
307 SIGADDSET(ps->ps_siginfo, sig);
308 } else {
309 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
310 SIGDELSET(ps->ps_siginfo, sig);
311 }
312 if (!(act->sa_flags & SA_RESTART))
313 SIGADDSET(ps->ps_sigintr, sig);
314 else
315 SIGDELSET(ps->ps_sigintr, sig);
316 if (act->sa_flags & SA_ONSTACK)
317 SIGADDSET(ps->ps_sigonstack, sig);
318 else
319 SIGDELSET(ps->ps_sigonstack, sig);
320 if (act->sa_flags & SA_RESETHAND)
321 SIGADDSET(ps->ps_sigreset, sig);
322 else
323 SIGDELSET(ps->ps_sigreset, sig);
324 if (act->sa_flags & SA_NODEFER)
325 SIGADDSET(ps->ps_signodefer, sig);
326 else
327 SIGDELSET(ps->ps_signodefer, sig);
328 if (sig == SIGCHLD) {
329 if (act->sa_flags & SA_NOCLDSTOP)
330 p->p_sigacts->ps_flag |= PS_NOCLDSTOP;
331 else
332 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP;
333 if (act->sa_flags & SA_NOCLDWAIT) {
334 /*
335 * Paranoia: since SA_NOCLDWAIT is implemented
336 * by reparenting the dying child to PID 1 (and
337 * trust it to reap the zombie), PID 1 itself
338 * is forbidden to set SA_NOCLDWAIT.
339 */
340 if (p->p_pid == 1)
341 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
342 else
343 p->p_sigacts->ps_flag |= PS_NOCLDWAIT;
344 } else {
345 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
346 }
347 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
348 ps->ps_flag |= PS_CLDSIGIGN;
349 else
350 ps->ps_flag &= ~PS_CLDSIGIGN;
351 }
352 /*
353 * Set bit in p_sigignore for signals that are set to SIG_IGN,
354 * and for signals set to SIG_DFL where the default is to
355 * ignore. However, don't put SIGCONT in p_sigignore, as we
356 * have to restart the process.
357 *
358 * Also remove the signal from the process and lwp signal
359 * list.
360 */
361 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
362 (sigprop(sig) & SA_IGNORE &&
363 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
364 SIGDELSET_ATOMIC(p->p_siglist, sig);
365 FOREACH_LWP_IN_PROC(lp, p) {
366 spin_lock(&lp->lwp_spin);
367 SIGDELSET(lp->lwp_siglist, sig);
368 spin_unlock(&lp->lwp_spin);
369 }
370 if (sig != SIGCONT) {
371 /* easier in ksignal */
372 SIGADDSET(p->p_sigignore, sig);
373 }
374 SIGDELSET(p->p_sigcatch, sig);
375 } else {
376 SIGDELSET(p->p_sigignore, sig);
377 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
378 SIGDELSET(p->p_sigcatch, sig);
379 else
380 SIGADDSET(p->p_sigcatch, sig);
381 }
382 }
383 lwkt_reltoken(&p->p_token);
384 return (0);
385 }
386
387 int
388 sys_sigaction(struct sigaction_args *uap)
389 {
390 struct sigaction act, oact;
391 struct sigaction *actp, *oactp;
392 int error;
393
394 actp = (uap->act != NULL) ? &act : NULL;
395 oactp = (uap->oact != NULL) ? &oact : NULL;
396 if (actp) {
397 error = copyin(uap->act, actp, sizeof(act));
398 if (error)
399 return (error);
400 }
401 error = kern_sigaction(uap->sig, actp, oactp);
402 if (oactp && !error) {
403 error = copyout(oactp, uap->oact, sizeof(oact));
404 }
405 return (error);
406 }
407
408 /*
409 * Initialize signal state for process 0;
410 * set to ignore signals that are ignored by default.
411 */
412 void
413 siginit(struct proc *p)
414 {
415 int i;
416
417 for (i = 1; i <= NSIG; i++)
418 if (sigprop(i) & SA_IGNORE && i != SIGCONT)
419 SIGADDSET(p->p_sigignore, i);
420 }
421
422 /*
423 * Reset signals for an exec of the specified process.
424 */
425 void
426 execsigs(struct proc *p)
427 {
428 struct sigacts *ps = p->p_sigacts;
429 struct lwp *lp;
430 int sig;
431
432 lp = ONLY_LWP_IN_PROC(p);
433
434 /*
435 * Reset caught signals. Held signals remain held
436 * through p_sigmask (unless they were caught,
437 * and are now ignored by default).
438 */
439 while (SIGNOTEMPTY(p->p_sigcatch)) {
440 sig = sig_ffs(&p->p_sigcatch);
441 SIGDELSET(p->p_sigcatch, sig);
442 if (sigprop(sig) & SA_IGNORE) {
443 if (sig != SIGCONT)
444 SIGADDSET(p->p_sigignore, sig);
445 SIGDELSET_ATOMIC(p->p_siglist, sig);
446 /* don't need spinlock */
447 SIGDELSET(lp->lwp_siglist, sig);
448 }
449 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
450 }
451
452 /*
453 * Reset stack state to the user stack.
454 * Clear set of signals caught on the signal stack.
455 */
456 lp->lwp_sigstk.ss_flags = SS_DISABLE;
457 lp->lwp_sigstk.ss_size = 0;
458 lp->lwp_sigstk.ss_sp = NULL;
459 lp->lwp_flags &= ~LWP_ALTSTACK;
460 /*
461 * Reset no zombies if child dies flag as Solaris does.
462 */
463 p->p_sigacts->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
464 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
465 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
466 }
467
468 /*
469 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc
470 *
471 * Manipulate signal mask. This routine is MP SAFE *ONLY* if
472 * p == curproc.
473 */
474 int
475 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset)
476 {
477 struct thread *td = curthread;
478 struct lwp *lp = td->td_lwp;
479 struct proc *p = td->td_proc;
480 int error;
481
482 lwkt_gettoken(&p->p_token);
483
484 if (oset != NULL)
485 *oset = lp->lwp_sigmask;
486
487 error = 0;
488 if (set != NULL) {
489 switch (how) {
490 case SIG_BLOCK:
491 SIG_CANTMASK(*set);
492 SIGSETOR(lp->lwp_sigmask, *set);
493 break;
494 case SIG_UNBLOCK:
495 SIGSETNAND(lp->lwp_sigmask, *set);
496 break;
497 case SIG_SETMASK:
498 SIG_CANTMASK(*set);
499 lp->lwp_sigmask = *set;
500 break;
501 default:
502 error = EINVAL;
503 break;
504 }
505 }
506
507 lwkt_reltoken(&p->p_token);
508
509 return (error);
510 }
511
512 /*
513 * sigprocmask()
514 *
515 * MPSAFE
516 */
517 int
518 sys_sigprocmask(struct sigprocmask_args *uap)
519 {
520 sigset_t set, oset;
521 sigset_t *setp, *osetp;
522 int error;
523
524 setp = (uap->set != NULL) ? &set : NULL;
525 osetp = (uap->oset != NULL) ? &oset : NULL;
526 if (setp) {
527 error = copyin(uap->set, setp, sizeof(set));
528 if (error)
529 return (error);
530 }
531 error = kern_sigprocmask(uap->how, setp, osetp);
532 if (osetp && !error) {
533 error = copyout(osetp, uap->oset, sizeof(oset));
534 }
535 return (error);
536 }
537
538 /*
539 * MPSAFE
540 */
541 int
542 kern_sigpending(struct __sigset *set)
543 {
544 struct lwp *lp = curthread->td_lwp;
545
546 *set = lwp_sigpend(lp);
547
548 return (0);
549 }
550
551 /*
552 * MPSAFE
553 */
554 int
555 sys_sigpending(struct sigpending_args *uap)
556 {
557 sigset_t set;
558 int error;
559
560 error = kern_sigpending(&set);
561
562 if (error == 0)
563 error = copyout(&set, uap->set, sizeof(set));
564 return (error);
565 }
566
567 /*
568 * Suspend process until signal, providing mask to be set
569 * in the meantime.
570 *
571 * MPSAFE
572 */
573 int
574 kern_sigsuspend(struct __sigset *set)
575 {
576 struct thread *td = curthread;
577 struct lwp *lp = td->td_lwp;
578 struct proc *p = td->td_proc;
579 struct sigacts *ps = p->p_sigacts;
580
581 /*
582 * When returning from sigsuspend, we want
583 * the old mask to be restored after the
584 * signal handler has finished. Thus, we
585 * save it here and mark the sigacts structure
586 * to indicate this.
587 */
588 lp->lwp_oldsigmask = lp->lwp_sigmask;
589 lp->lwp_flags |= LWP_OLDMASK;
590
591 SIG_CANTMASK(*set);
592 lp->lwp_sigmask = *set;
593 while (tsleep(ps, PCATCH, "pause", 0) == 0)
594 /* void */;
595 /* always return EINTR rather than ERESTART... */
596 return (EINTR);
597 }
598
599 /*
600 * Note nonstandard calling convention: libc stub passes mask, not
601 * pointer, to save a copyin.
602 *
603 * MPSAFE
604 */
605 int
606 sys_sigsuspend(struct sigsuspend_args *uap)
607 {
608 sigset_t mask;
609 int error;
610
611 error = copyin(uap->sigmask, &mask, sizeof(mask));
612 if (error)
613 return (error);
614
615 error = kern_sigsuspend(&mask);
616
617 return (error);
618 }
619
620 /*
621 * MPSAFE
622 */
623 int
624 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss)
625 {
626 struct thread *td = curthread;
627 struct lwp *lp = td->td_lwp;
628 struct proc *p = td->td_proc;
629
630 if ((lp->lwp_flags & LWP_ALTSTACK) == 0)
631 lp->lwp_sigstk.ss_flags |= SS_DISABLE;
632
633 if (oss)
634 *oss = lp->lwp_sigstk;
635
636 if (ss) {
637 if (ss->ss_flags & ~SS_DISABLE)
638 return (EINVAL);
639 if (ss->ss_flags & SS_DISABLE) {
640 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK)
641 return (EPERM);
642 lp->lwp_flags &= ~LWP_ALTSTACK;
643 lp->lwp_sigstk.ss_flags = ss->ss_flags;
644 } else {
645 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
646 return (ENOMEM);
647 lp->lwp_flags |= LWP_ALTSTACK;
648 lp->lwp_sigstk = *ss;
649 }
650 }
651
652 return (0);
653 }
654
655 /*
656 * MPSAFE
657 */
658 int
659 sys_sigaltstack(struct sigaltstack_args *uap)
660 {
661 stack_t ss, oss;
662 int error;
663
664 if (uap->ss) {
665 error = copyin(uap->ss, &ss, sizeof(ss));
666 if (error)
667 return (error);
668 }
669
670 error = kern_sigaltstack(uap->ss ? &ss : NULL, uap->oss ? &oss : NULL);
671
672 if (error == 0 && uap->oss)
673 error = copyout(&oss, uap->oss, sizeof(*uap->oss));
674 return (error);
675 }
676
677 /*
678 * Common code for kill process group/broadcast kill.
679 * cp is calling process.
680 */
681 struct killpg_info {
682 int nfound;
683 int sig;
684 };
685
686 static int killpg_all_callback(struct proc *p, void *data);
687
688 static int
689 dokillpg(int sig, int pgid, int all)
690 {
691 struct killpg_info info;
692 struct proc *cp = curproc;
693 struct proc *p;
694 struct pgrp *pgrp;
695
696 info.nfound = 0;
697 info.sig = sig;
698
699 if (all) {
700 /*
701 * broadcast
702 */
703 allproc_scan(killpg_all_callback, &info, 0);
704 } else {
705 if (pgid == 0) {
706 /*
707 * zero pgid means send to my process group.
708 */
709 pgrp = cp->p_pgrp;
710 pgref(pgrp);
711 } else {
712 pgrp = pgfind(pgid);
713 if (pgrp == NULL)
714 return (ESRCH);
715 }
716
717 /*
718 * Must interlock all signals against fork
719 */
720 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
721 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
722 if (p->p_pid <= 1 ||
723 p->p_stat == SZOMB ||
724 (p->p_flags & P_SYSTEM) ||
725 !CANSIGNAL(p, sig, 0)) {
726 continue;
727 }
728 ++info.nfound;
729 if (sig)
730 ksignal(p, sig);
731 }
732 lockmgr(&pgrp->pg_lock, LK_RELEASE);
733 pgrel(pgrp);
734 }
735 return (info.nfound ? 0 : ESRCH);
736 }
737
738 static int
739 killpg_all_callback(struct proc *p, void *data)
740 {
741 struct killpg_info *info = data;
742
743 if (p->p_pid <= 1 || (p->p_flags & P_SYSTEM) ||
744 p == curproc || !CANSIGNAL(p, info->sig, 0)) {
745 return (0);
746 }
747 ++info->nfound;
748 if (info->sig)
749 ksignal(p, info->sig);
750 return(0);
751 }
752
753 /*
754 * Send a general signal to a process or LWPs within that process.
755 *
756 * Note that new signals cannot be sent if a process is exiting or already
757 * a zombie, but we return success anyway as userland is likely to not handle
758 * the race properly.
759 *
760 * No requirements.
761 */
762 int
763 kern_kill(int sig, pid_t pid, lwpid_t tid)
764 {
765 int t;
766
767 if ((u_int)sig > _SIG_MAXSIG)
768 return (EINVAL);
769
770 if (pid > 0) {
771 struct proc *p;
772 struct lwp *lp = NULL;
773
774 /*
775 * Send a signal to a single process. If the kill() is
776 * racing an exiting process which has not yet been reaped
777 * act as though the signal was delivered successfully but
778 * don't actually try to deliver the signal.
779 */
780 if ((p = pfind(pid)) == NULL) {
781 if ((p = zpfind(pid)) == NULL)
782 return (ESRCH);
783 PRELE(p);
784 return (0);
785 }
786 if (p != curproc) {
787 lwkt_gettoken_shared(&p->p_token);
788 if (!CANSIGNAL(p, sig, 1)) {
789 lwkt_reltoken(&p->p_token);
790 PRELE(p);
791 return (EPERM);
792 }
793 lwkt_reltoken(&p->p_token);
794 }
795
796 /*
797 * NOP if the process is exiting. Note that lwpsignal() is
798 * called directly with P_WEXIT set to kill individual LWPs
799 * during exit, which is allowed.
800 */
801 if (p->p_flags & P_WEXIT) {
802 PRELE(p);
803 return (0);
804 }
805 if (tid != -1) {
806 lwkt_gettoken_shared(&p->p_token);
807 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid);
808 if (lp == NULL) {
809 lwkt_reltoken(&p->p_token);
810 PRELE(p);
811 return (ESRCH);
812 }
813 LWPHOLD(lp);
814 lwkt_reltoken(&p->p_token);
815 }
816 if (sig)
817 lwpsignal(p, lp, sig);
818 if (lp)
819 LWPRELE(lp);
820 PRELE(p);
821
822 return (0);
823 }
824
825 /*
826 * If we come here, pid is a special broadcast pid.
827 * This doesn't mix with a tid.
828 */
829 if (tid != -1)
830 return (EINVAL);
831
832 switch (pid) {
833 case -1: /* broadcast signal */
834 t = (dokillpg(sig, 0, 1));
835 break;
836 case 0: /* signal own process group */
837 t = (dokillpg(sig, 0, 0));
838 break;
839 default: /* negative explicit process group */
840 t = (dokillpg(sig, -pid, 0));
841 break;
842 }
843 return t;
844 }
845
846 int
847 sys_kill(struct kill_args *uap)
848 {
849 int error;
850
851 error = kern_kill(uap->signum, uap->pid, -1);
852 return (error);
853 }
854
855 int
856 sys_lwp_kill(struct lwp_kill_args *uap)
857 {
858 int error;
859 pid_t pid = uap->pid;
860
861 /*
862 * A tid is mandatory for lwp_kill(), otherwise
863 * you could simply use kill().
864 */
865 if (uap->tid == -1)
866 return (EINVAL);
867
868 /*
869 * To save on a getpid() function call for intra-process
870 * signals, pid == -1 means current process.
871 */
872 if (pid == -1)
873 pid = curproc->p_pid;
874
875 error = kern_kill(uap->signum, pid, uap->tid);
876 return (error);
877 }
878
879 /*
880 * Send a signal to a process group.
881 */
882 void
883 gsignal(int pgid, int sig)
884 {
885 struct pgrp *pgrp;
886
887 if (pgid && (pgrp = pgfind(pgid)))
888 pgsignal(pgrp, sig, 0);
889 }
890
891 /*
892 * Send a signal to a process group. If checktty is 1,
893 * limit to members which have a controlling terminal.
894 *
895 * pg_lock interlocks against a fork that might be in progress, to
896 * ensure that the new child process picks up the signal.
897 */
898 void
899 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
900 {
901 struct proc *p;
902
903 /*
904 * Must interlock all signals against fork
905 */
906 if (pgrp) {
907 pgref(pgrp);
908 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
909 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
910 if (checkctty == 0 || p->p_flags & P_CONTROLT)
911 ksignal(p, sig);
912 }
913 lockmgr(&pgrp->pg_lock, LK_RELEASE);
914 pgrel(pgrp);
915 }
916 }
917
918 /*
919 * Send a signal caused by a trap to the current lwp. If it will be caught
920 * immediately, deliver it with correct code. Otherwise, post it normally.
921 *
922 * These signals may ONLY be delivered to the specified lwp and may never
923 * be delivered to the process generically.
924 */
925 void
926 trapsignal(struct lwp *lp, int sig, u_long code)
927 {
928 struct proc *p = lp->lwp_proc;
929 struct sigacts *ps = p->p_sigacts;
930
931 /*
932 * If we are a virtual kernel running an emulated user process
933 * context, switch back to the virtual kernel context before
934 * trying to post the signal.
935 */
936 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
937 struct trapframe *tf = lp->lwp_md.md_regs;
938 tf->tf_trapno = 0;
939 vkernel_trap(lp, tf);
940 }
941
942 if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
943 !SIGISMEMBER(lp->lwp_sigmask, sig)) {
944 lp->lwp_ru.ru_nsignals++;
945 #ifdef KTRACE
946 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
947 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)],
948 &lp->lwp_sigmask, code);
949 #endif
950 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
951 &lp->lwp_sigmask, code);
952 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
953 if (!SIGISMEMBER(ps->ps_signodefer, sig))
954 SIGADDSET(lp->lwp_sigmask, sig);
955 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
956 /*
957 * See kern_sigaction() for origin of this code.
958 */
959 SIGDELSET(p->p_sigcatch, sig);
960 if (sig != SIGCONT &&
961 sigprop(sig) & SA_IGNORE)
962 SIGADDSET(p->p_sigignore, sig);
963 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
964 }
965 } else {
966 lp->lwp_code = code; /* XXX for core dump/debugger */
967 lp->lwp_sig = sig; /* XXX to verify code */
968 lwpsignal(p, lp, sig);
969 }
970 }
971
972 /*
973 * Find a suitable lwp to deliver the signal to. Returns NULL if all
974 * lwps hold the signal blocked.
975 *
976 * Caller must hold p->p_token.
977 *
978 * Returns a lp or NULL. If non-NULL the lp is held and its token is
979 * acquired.
980 */
981 static struct lwp *
982 find_lwp_for_signal(struct proc *p, int sig)
983 {
984 struct lwp *lp;
985 struct lwp *run, *sleep, *stop;
986
987 /*
988 * If the running/preempted thread belongs to the proc to which
989 * the signal is being delivered and this thread does not block
990 * the signal, then we can avoid a context switch by delivering
991 * the signal to this thread, because it will return to userland
992 * soon anyways.
993 */
994 lp = lwkt_preempted_proc();
995 if (lp != NULL && lp->lwp_proc == p) {
996 LWPHOLD(lp);
997 lwkt_gettoken(&lp->lwp_token);
998 if (!SIGISMEMBER(lp->lwp_sigmask, sig)) {
999 /* return w/ token held */
1000 return (lp);
1001 }
1002 lwkt_reltoken(&lp->lwp_token);
1003 LWPRELE(lp);
1004 }
1005
1006 run = sleep = stop = NULL;
1007 FOREACH_LWP_IN_PROC(lp, p) {
1008 /*
1009 * If the signal is being blocked by the lwp, then this
1010 * lwp is not eligible for receiving the signal.
1011 */
1012 LWPHOLD(lp);
1013 lwkt_gettoken(&lp->lwp_token);
1014
1015 if (SIGISMEMBER(lp->lwp_sigmask, sig)) {
1016 lwkt_reltoken(&lp->lwp_token);
1017 LWPRELE(lp);
1018 continue;
1019 }
1020
1021 switch (lp->lwp_stat) {
1022 case LSRUN:
1023 if (sleep) {
1024 lwkt_token_swap();
1025 lwkt_reltoken(&sleep->lwp_token);
1026 LWPRELE(sleep);
1027 sleep = NULL;
1028 run = lp;
1029 } else if (stop) {
1030 lwkt_token_swap();
1031 lwkt_reltoken(&stop->lwp_token);
1032 LWPRELE(stop);
1033 stop = NULL;
1034 run = lp;
1035 } else {
1036 run = lp;
1037 }
1038 break;
1039 case LSSLEEP:
1040 if (lp->lwp_flags & LWP_SINTR) {
1041 if (sleep) {
1042 lwkt_reltoken(&lp->lwp_token);
1043 LWPRELE(lp);
1044 } else if (stop) {
1045 lwkt_token_swap();
1046 lwkt_reltoken(&stop->lwp_token);
1047 LWPRELE(stop);
1048 stop = NULL;
1049 sleep = lp;
1050 } else {
1051 sleep = lp;
1052 }
1053 } else {
1054 lwkt_reltoken(&lp->lwp_token);
1055 LWPRELE(lp);
1056 }
1057 break;
1058 case LSSTOP:
1059 if (sleep) {
1060 lwkt_reltoken(&lp->lwp_token);
1061 LWPRELE(lp);
1062 } else if (stop) {
1063 lwkt_reltoken(&lp->lwp_token);
1064 LWPRELE(lp);
1065 } else {
1066 stop = lp;
1067 }
1068 break;
1069 }
1070 if (run)
1071 break;
1072 }
1073
1074 if (run != NULL)
1075 return (run);
1076 else if (sleep != NULL)
1077 return (sleep);
1078 else
1079 return (stop);
1080 }
1081
1082 /*
1083 * Send the signal to the process. If the signal has an action, the action
1084 * is usually performed by the target process rather than the caller; we add
1085 * the signal to the set of pending signals for the process.
1086 *
1087 * Exceptions:
1088 * o When a stop signal is sent to a sleeping process that takes the
1089 * default action, the process is stopped without awakening it.
1090 * o SIGCONT restarts stopped processes (or puts them back to sleep)
1091 * regardless of the signal action (eg, blocked or ignored).
1092 *
1093 * Other ignored signals are discarded immediately.
1094 *
1095 * If the caller wishes to call this function from a hard code section the
1096 * caller must already hold p->p_token (see kern_clock.c).
1097 *
1098 * No requirements.
1099 */
1100 void
1101 ksignal(struct proc *p, int sig)
1102 {
1103 lwpsignal(p, NULL, sig);
1104 }
1105
1106 /*
1107 * The core for ksignal. lp may be NULL, then a suitable thread
1108 * will be chosen. If not, lp MUST be a member of p.
1109 *
1110 * If the caller wishes to call this function from a hard code section the
1111 * caller must already hold p->p_token.
1112 *
1113 * No requirements.
1114 */
1115 void
1116 lwpsignal(struct proc *p, struct lwp *lp, int sig)
1117 {
1118 struct proc *q;
1119 sig_t action;
1120 int prop;
1121
1122 if (sig > _SIG_MAXSIG || sig <= 0) {
1123 kprintf("lwpsignal: signal %d\n", sig);
1124 panic("lwpsignal signal number");
1125 }
1126
1127 KKASSERT(lp == NULL || lp->lwp_proc == p);
1128
1129 /*
1130 * We don't want to race... well, all sorts of things. Get appropriate
1131 * tokens.
1132 *
1133 * Don't try to deliver a generic signal to an exiting process,
1134 * the signal structures could be in flux. We check the LWP later
1135 * on.
1136 */
1137 PHOLD(p);
1138 if (lp) {
1139 LWPHOLD(lp);
1140 lwkt_gettoken(&lp->lwp_token);
1141 } else {
1142 lwkt_gettoken(&p->p_token);
1143 if (p->p_flags & P_WEXIT)
1144 goto out;
1145 }
1146
1147 prop = sigprop(sig);
1148
1149 /*
1150 * If proc is traced, always give parent a chance;
1151 * if signal event is tracked by procfs, give *that*
1152 * a chance, as well.
1153 */
1154 if ((p->p_flags & P_TRACED) || (p->p_stops & S_SIG)) {
1155 action = SIG_DFL;
1156 } else {
1157 /*
1158 * Do not try to deliver signals to an exiting lwp other
1159 * than SIGKILL. Note that we must still deliver the signal
1160 * if P_WEXIT is set in the process flags.
1161 */
1162 if (lp && (lp->lwp_mpflags & LWP_MP_WEXIT) && sig != SIGKILL) {
1163 lwkt_reltoken(&lp->lwp_token);
1164 LWPRELE(lp);
1165 PRELE(p);
1166 return;
1167 }
1168
1169 /*
1170 * If the signal is being ignored, then we forget about
1171 * it immediately. NOTE: We don't set SIGCONT in p_sigignore,
1172 * and if it is set to SIG_IGN, action will be SIG_DFL here.
1173 */
1174 if (SIGISMEMBER(p->p_sigignore, sig)) {
1175 /*
1176 * Even if a signal is set SIG_IGN, it may still be
1177 * lurking in a kqueue.
1178 */
1179 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
1180 if (lp) {
1181 lwkt_reltoken(&lp->lwp_token);
1182 LWPRELE(lp);
1183 } else {
1184 lwkt_reltoken(&p->p_token);
1185 }
1186 PRELE(p);
1187 return;
1188 }
1189 if (SIGISMEMBER(p->p_sigcatch, sig))
1190 action = SIG_CATCH;
1191 else
1192 action = SIG_DFL;
1193 }
1194
1195 /*
1196 * If continuing, clear any pending STOP signals for the whole
1197 * process.
1198 */
1199 if (prop & SA_CONT) {
1200 lwkt_gettoken(&p->p_token);
1201 SIG_STOPSIGMASK_ATOMIC(p->p_siglist);
1202 lwkt_reltoken(&p->p_token);
1203 }
1204
1205 if (prop & SA_STOP) {
1206 /*
1207 * If sending a tty stop signal to a member of an orphaned
1208 * process group, discard the signal here if the action
1209 * is default; don't stop the process below if sleeping,
1210 * and don't clear any pending SIGCONT.
1211 */
1212 if ((prop & SA_TTYSTOP) && p->p_pgrp->pg_jobc == 0 &&
1213 action == SIG_DFL) {
1214 if (lp) {
1215 lwkt_reltoken(&lp->lwp_token);
1216 LWPRELE(lp);
1217 } else {
1218 lwkt_reltoken(&p->p_token);
1219 }
1220 PRELE(p);
1221 return;
1222 }
1223 lwkt_gettoken(&p->p_token);
1224 SIG_CONTSIGMASK_ATOMIC(p->p_siglist);
1225 p->p_flags &= ~P_CONTINUED;
1226 lwkt_reltoken(&p->p_token);
1227 }
1228
1229 if (p->p_stat == SSTOP) {
1230 /*
1231 * Nobody can handle this signal, add it to the lwp or
1232 * process pending list
1233 */
1234 lwkt_gettoken(&p->p_token);
1235 if (p->p_stat != SSTOP) {
1236 lwkt_reltoken(&p->p_token);
1237 goto not_stopped;
1238 }
1239 sigsetfrompid(curthread, p, sig);
1240 if (lp) {
1241 spin_lock(&lp->lwp_spin);
1242 SIGADDSET(lp->lwp_siglist, sig);
1243 spin_unlock(&lp->lwp_spin);
1244 } else {
1245 SIGADDSET_ATOMIC(p->p_siglist, sig);
1246 }
1247
1248 /*
1249 * If the process is stopped and is being traced, then no
1250 * further action is necessary.
1251 */
1252 if (p->p_flags & P_TRACED) {
1253 lwkt_reltoken(&p->p_token);
1254 goto out;
1255 }
1256
1257 /*
1258 * If the process is stopped and receives a KILL signal,
1259 * make the process runnable.
1260 */
1261 if (sig == SIGKILL) {
1262 proc_unstop(p, SSTOP);
1263 lwkt_reltoken(&p->p_token);
1264 goto active_process;
1265 }
1266
1267 /*
1268 * If the process is stopped and receives a CONT signal,
1269 * then try to make the process runnable again.
1270 */
1271 if (prop & SA_CONT) {
1272 /*
1273 * If SIGCONT is default (or ignored), we continue the
1274 * process but don't leave the signal in p_siglist, as
1275 * it has no further action. If SIGCONT is held, we
1276 * continue the process and leave the signal in
1277 * p_siglist. If the process catches SIGCONT, let it
1278 * handle the signal itself.
1279 *
1280 * XXX what if the signal is being held blocked?
1281 *
1282 * Token required to interlock kern_wait().
1283 * Reparenting can also cause a race so we have to
1284 * hold (q).
1285 */
1286 q = p->p_pptr;
1287 PHOLD(q);
1288 lwkt_gettoken(&q->p_token);
1289 p->p_flags |= P_CONTINUED;
1290 wakeup(q);
1291 if (action == SIG_DFL)
1292 SIGDELSET_ATOMIC(p->p_siglist, sig);
1293 proc_unstop(p, SSTOP);
1294 lwkt_reltoken(&q->p_token);
1295 PRELE(q);
1296 lwkt_reltoken(&p->p_token);
1297 if (action == SIG_CATCH)
1298 goto active_process;
1299 goto out;
1300 }
1301
1302 /*
1303 * If the process is stopped and receives another STOP
1304 * signal, we do not need to stop it again. If we did
1305 * the shell could get confused.
1306 *
1307 * However, if the current/preempted lwp is part of the
1308 * process receiving the signal, we need to keep it,
1309 * so that this lwp can stop in issignal() later, as
1310 * we don't want to wait until it reaches userret!
1311 */
1312 if (prop & SA_STOP) {
1313 if (lwkt_preempted_proc() == NULL ||
1314 lwkt_preempted_proc()->lwp_proc != p) {
1315 SIGDELSET_ATOMIC(p->p_siglist, sig);
1316 }
1317 }
1318
1319 /*
1320 * Otherwise the process is stopped and it received some
1321 * signal, which does not change its stopped state. When
1322 * the process is continued a wakeup(p) will be issued which
1323 * will wakeup any threads sleeping in tstop().
1324 */
1325 lwkt_reltoken(&p->p_token);
1326 goto out;
1327 /* NOTREACHED */
1328 }
1329 not_stopped:
1330 ;
1331 /* else not stopped */
1332 active_process:
1333
1334 /*
1335 * Never deliver a lwp-specific signal to a random lwp.
1336 */
1337 if (lp == NULL) {
1338 /* NOTE: returns lp w/ token held */
1339 lp = find_lwp_for_signal(p, sig);
1340 if (lp) {
1341 if (SIGISMEMBER(lp->lwp_sigmask, sig)) {
1342 lwkt_reltoken(&lp->lwp_token);
1343 LWPRELE(lp);
1344 lp = NULL;
1345 /* maintain proc token */
1346 } else {
1347 lwkt_token_swap();
1348 lwkt_reltoken(&p->p_token);
1349 /* maintain lp token */
1350 }
1351 }
1352 }
1353
1354 /*
1355 * Deliver to the process generically if (1) the signal is being
1356 * sent to any thread or (2) we could not find a thread to deliver
1357 * it to.
1358 */
1359 if (lp == NULL) {
1360 sigsetfrompid(curthread, p, sig);
1361 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
1362 SIGADDSET_ATOMIC(p->p_siglist, sig);
1363 goto out;
1364 }
1365
1366 /*
1367 * Deliver to a specific LWP whether it masks it or not. It will
1368 * not be dispatched if masked but we must still deliver it.
1369 */
1370 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
1371 (p->p_flags & P_TRACED) == 0) {
1372 lwkt_gettoken(&p->p_token);
1373 p->p_nice = NZERO;
1374 lwkt_reltoken(&p->p_token);
1375 }
1376
1377 /*
1378 * If the process receives a STOP signal which indeed needs to
1379 * stop the process, do so. If the process chose to catch the
1380 * signal, it will be treated like any other signal.
1381 */
1382 if ((prop & SA_STOP) && action == SIG_DFL) {
1383 /*
1384 * If a child holding parent blocked, stopping
1385 * could cause deadlock. Take no action at this
1386 * time.
1387 */
1388 lwkt_gettoken(&p->p_token);
1389 if (p->p_flags & P_PPWAIT) {
1390 sigsetfrompid(curthread, p, sig);
1391 SIGADDSET_ATOMIC(p->p_siglist, sig);
1392 lwkt_reltoken(&p->p_token);
1393 goto out;
1394 }
1395
1396 /*
1397 * Do not actually try to manipulate the process, but simply
1398 * stop it. Lwps will stop as soon as they safely can.
1399 *
1400 * Ignore stop if the process is exiting.
1401 */
1402 if ((p->p_flags & P_WEXIT) == 0) {
1403 p->p_xstat = sig;
1404 proc_stop(p, SSTOP);
1405 }
1406 lwkt_reltoken(&p->p_token);
1407 goto out;
1408 }
1409
1410 /*
1411 * If it is a CONT signal with default action, just ignore it.
1412 */
1413 if ((prop & SA_CONT) && action == SIG_DFL)
1414 goto out;
1415
1416 /*
1417 * Mark signal pending at this specific thread.
1418 */
1419 sigsetfrompid(curthread, p, sig);
1420 spin_lock(&lp->lwp_spin);
1421 SIGADDSET(lp->lwp_siglist, sig);
1422 spin_unlock(&lp->lwp_spin);
1423
1424 lwp_signotify(lp);
1425
1426 out:
1427 if (lp) {
1428 lwkt_reltoken(&lp->lwp_token);
1429 LWPRELE(lp);
1430 } else {
1431 lwkt_reltoken(&p->p_token);
1432 }
1433 PRELE(p);
1434 }
1435
1436 /*
1437 * Notify the LWP that a signal has arrived. The LWP does not have to be
1438 * sleeping on the current cpu.
1439 *
1440 * p->p_token and lp->lwp_token must be held on call.
1441 *
1442 * We can only safely schedule the thread on its current cpu and only if
1443 * one of the SINTR flags is set. If an SINTR flag is set AND we are on
1444 * the correct cpu we are properly interlocked, otherwise we could be
1445 * racing other thread transition states (or the lwp is on the user scheduler
1446 * runq but not scheduled) and must not do anything.
1447 *
1448 * Since we hold the lwp token we know the lwp cannot be ripped out from
1449 * under us so we can safely hold it to prevent it from being ripped out
1450 * from under us if we are forced to IPI another cpu to make the local
1451 * checks there.
1452 *
1453 * Adjustment of lp->lwp_stat can only occur when we hold the lwp_token,
1454 * which we won't in an IPI so any fixups have to be done here, effectively
1455 * replicating part of what setrunnable() does.
1456 */
1457 static void
1458 lwp_signotify(struct lwp *lp)
1459 {
1460 thread_t dtd;
1461
1462 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_token);
1463 dtd = lp->lwp_thread;
1464
1465 crit_enter();
1466 if (lp == lwkt_preempted_proc()) {
1467 /*
1468 * lwp is on the current cpu AND it is currently running
1469 * (we preempted it).
1470 */
1471 signotify();
1472 } else if (lp->lwp_flags & LWP_SINTR) {
1473 /*
1474 * lwp is sitting in tsleep() with PCATCH set
1475 */
1476 if (dtd->td_gd == mycpu) {
1477 setrunnable(lp);
1478 } else {
1479 /*
1480 * We can only adjust lwp_stat while we hold the
1481 * lwp_token, and we won't in the IPI function.
1482 */
1483 LWPHOLD(lp);
1484 if (lp->lwp_stat == LSSTOP)
1485 lp->lwp_stat = LSSLEEP;
1486 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1487 }
1488 } else if (dtd->td_flags & TDF_SINTR) {
1489 /*
1490 * lwp is sitting in lwkt_sleep() with PCATCH set.
1491 */
1492 if (dtd->td_gd == mycpu) {
1493 setrunnable(lp);
1494 } else {
1495 /*
1496 * We can only adjust lwp_stat while we hold the
1497 * lwp_token, and we won't in the IPI function.
1498 */
1499 LWPHOLD(lp);
1500 if (lp->lwp_stat == LSSTOP)
1501 lp->lwp_stat = LSSLEEP;
1502 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1503 }
1504 } else {
1505 /*
1506 * Otherwise the lwp is either in some uninterruptible state
1507 * or it is on the userland scheduler's runqueue waiting to
1508 * be scheduled to a cpu, or it is running in userland. We
1509 * generally want to send an IPI so a running target gets the
1510 * signal ASAP, otherwise a scheduler-tick worth of latency
1511 * will occur.
1512 *
1513 * Issue an IPI to the remote cpu to knock it into the kernel,
1514 * remote cpu will issue the cpu-local signotify() if the IPI
1515 * preempts the desired thread.
1516 */
1517 if (dtd->td_gd != mycpu) {
1518 LWPHOLD(lp);
1519 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1520 }
1521 }
1522 crit_exit();
1523 }
1524
1525 /*
1526 * This function is called via an IPI so we cannot call setrunnable() here
1527 * (because while we hold the lp we don't own its token, and can't get it
1528 * from an IPI).
1529 *
1530 * We are interlocked by virtue of being on the same cpu as the target. If
1531 * we still are and LWP_SINTR or TDF_SINTR is set we can safely schedule
1532 * the target thread.
1533 */
1534 static void
1535 lwp_signotify_remote(void *arg)
1536 {
1537 struct lwp *lp = arg;
1538 thread_t td = lp->lwp_thread;
1539
1540 if (lp == lwkt_preempted_proc()) {
1541 signotify();
1542 LWPRELE(lp);
1543 } else if (td->td_gd == mycpu) {
1544 if ((lp->lwp_flags & LWP_SINTR) ||
1545 (td->td_flags & TDF_SINTR)) {
1546 lwkt_schedule(td);
1547 }
1548 LWPRELE(lp);
1549 } else {
1550 lwkt_send_ipiq(td->td_gd, lwp_signotify_remote, lp);
1551 /* LWPHOLD() is forwarded to the target cpu */
1552 }
1553 }
1554
1555 /*
1556 * Caller must hold p->p_token
1557 */
1558 void
1559 proc_stop(struct proc *p, int sig)
1560 {
1561 struct proc *q;
1562 struct lwp *lp;
1563
1564 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
1565
1566 /*
1567 * If somebody raced us, be happy with it. SCORE overrides SSTOP.
1568 */
1569 if (sig == SCORE) {
1570 if (p->p_stat == SCORE || p->p_stat == SZOMB)
1571 return;
1572 } else {
1573 if (p->p_stat == SSTOP || p->p_stat == SCORE ||
1574 p->p_stat == SZOMB) {
1575 return;
1576 }
1577 }
1578 p->p_stat = sig;
1579
1580 FOREACH_LWP_IN_PROC(lp, p) {
1581 LWPHOLD(lp);
1582 lwkt_gettoken(&lp->lwp_token);
1583
1584 switch (lp->lwp_stat) {
1585 case LSSTOP:
1586 /*
1587 * Do nothing, we are already counted in
1588 * p_nstopped.
1589 */
1590 break;
1591
1592 case LSSLEEP:
1593 /*
1594 * We're sleeping, but we will stop before
1595 * returning to userspace, so count us
1596 * as stopped as well. We set LWP_MP_WSTOP
1597 * to signal the lwp that it should not
1598 * increase p_nstopped when reaching tstop().
1599 *
1600 * LWP_MP_WSTOP is protected by lp->lwp_token.
1601 */
1602 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) {
1603 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP);
1604 ++p->p_nstopped;
1605 }
1606 break;
1607
1608 case LSRUN:
1609 /*
1610 * We might notify ourself, but that's not
1611 * a problem.
1612 */
1613 lwp_signotify(lp);
1614 break;
1615 }
1616 lwkt_reltoken(&lp->lwp_token);
1617 LWPRELE(lp);
1618 }
1619
1620 if (p->p_nstopped == p->p_nthreads) {
1621 /*
1622 * Token required to interlock kern_wait(). Reparenting can
1623 * also cause a race so we have to hold (q).
1624 */
1625 q = p->p_pptr;
1626 PHOLD(q);
1627 lwkt_gettoken(&q->p_token);
1628 p->p_flags &= ~P_WAITED;
1629 wakeup(q);
1630 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1631 ksignal(p->p_pptr, SIGCHLD);
1632 lwkt_reltoken(&q->p_token);
1633 PRELE(q);
1634 }
1635 }
1636
1637 /*
1638 * Caller must hold p_token
1639 */
1640 void
1641 proc_unstop(struct proc *p, int sig)
1642 {
1643 struct lwp *lp;
1644
1645 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
1646
1647 if (p->p_stat != sig)
1648 return;
1649
1650 p->p_stat = SACTIVE;
1651
1652 FOREACH_LWP_IN_PROC(lp, p) {
1653 LWPHOLD(lp);
1654 lwkt_gettoken(&lp->lwp_token);
1655
1656 switch (lp->lwp_stat) {
1657 case LSRUN:
1658 /*
1659 * Uh? Not stopped? Well, I guess that's okay.
1660 */
1661 if (bootverbose)
1662 kprintf("proc_unstop: lwp %d/%d not sleeping\n",
1663 p->p_pid, lp->lwp_tid);
1664 break;
1665
1666 case LSSLEEP:
1667 /*
1668 * Still sleeping. Don't bother waking it up.
1669 * However, if this thread was counted as
1670 * stopped, undo this.
1671 *
1672 * Nevertheless we call setrunnable() so that it
1673 * will wake up in case a signal or timeout arrived
1674 * in the meantime.
1675 *
1676 * LWP_MP_WSTOP is protected by lp->lwp_token.
1677 */
1678 if (lp->lwp_mpflags & LWP_MP_WSTOP) {
1679 atomic_clear_int(&lp->lwp_mpflags,
1680 LWP_MP_WSTOP);
1681 --p->p_nstopped;
1682 } else {
1683 if (bootverbose)
1684 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n",
1685 p->p_pid, lp->lwp_tid);
1686 }
1687 /* FALLTHROUGH */
1688
1689 case LSSTOP:
1690 /*
1691 * This handles any lwp's waiting in a tsleep with
1692 * SIGCATCH.
1693 */
1694 lwp_signotify(lp);
1695 break;
1696
1697 }
1698 lwkt_reltoken(&lp->lwp_token);
1699 LWPRELE(lp);
1700 }
1701
1702 /*
1703 * This handles any lwp's waiting in tstop(). We have interlocked
1704 * the setting of p_stat by acquiring and releasing each lpw's
1705 * token.
1706 */
1707 wakeup(p);
1708 }
1709
1710 /*
1711 * Wait for all threads except the current thread to stop.
1712 */
1713 static void
1714 proc_stopwait(struct proc *p)
1715 {
1716 while ((p->p_stat == SSTOP || p->p_stat == SCORE) &&
1717 p->p_nstopped < p->p_nthreads - 1) {
1718 tsleep_interlock(&p->p_nstopped, 0);
1719 if (p->p_nstopped < p->p_nthreads - 1) {
1720 tsleep(&p->p_nstopped, PINTERLOCKED, "stopwt", hz);
1721 }
1722 }
1723 }
1724
1725 /*
1726 * No requirements.
1727 */
1728 static int
1729 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1730 {
1731 sigset_t savedmask, set;
1732 struct proc *p = curproc;
1733 struct lwp *lp = curthread->td_lwp;
1734 int error, sig, hz, timevalid = 0;
1735 struct timespec rts, ets, ts;
1736 struct timeval tv;
1737
1738 error = 0;
1739 sig = 0;
1740 ets.tv_sec = 0; /* silence compiler warning */
1741 ets.tv_nsec = 0; /* silence compiler warning */
1742 SIG_CANTMASK(waitset);
1743 savedmask = lp->lwp_sigmask;
1744
1745 if (timeout) {
1746 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1747 timeout->tv_nsec < 1000000000) {
1748 timevalid = 1;
1749 getnanouptime(&rts);
1750 ets = rts;
1751 timespecadd(&ets, timeout);
1752 }
1753 }
1754
1755 for (;;) {
1756 set = lwp_sigpend(lp);
1757 SIGSETAND(set, waitset);
1758 if ((sig = sig_ffs(&set)) != 0) {
1759 SIGFILLSET(lp->lwp_sigmask);
1760 SIGDELSET(lp->lwp_sigmask, sig);
1761 SIG_CANTMASK(lp->lwp_sigmask);
1762 sig = issignal(lp, 1, 0);
1763 /*
1764 * It may be a STOP signal, in the case, issignal
1765 * returns 0, because we may stop there, and new
1766 * signal can come in, we should restart if we got
1767 * nothing.
1768 */
1769 if (sig == 0)
1770 continue;
1771 else
1772 break;
1773 }
1774
1775 /*
1776 * Previous checking got nothing, and we retried but still
1777 * got nothing, we should return the error status.
1778 */
1779 if (error)
1780 break;
1781
1782 /*
1783 * POSIX says this must be checked after looking for pending
1784 * signals.
1785 */
1786 if (timeout) {
1787 if (timevalid == 0) {
1788 error = EINVAL;
1789 break;
1790 }
1791 getnanouptime(&rts);
1792 if (timespeccmp(&rts, &ets, >=)) {
1793 error = EAGAIN;
1794 break;
1795 }
1796 ts = ets;
1797 timespecsub(&ts, &rts);
1798 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1799 hz = tvtohz_high(&tv);
1800 } else {
1801 hz = 0;
1802 }
1803
1804 lp->lwp_sigmask = savedmask;
1805 SIGSETNAND(lp->lwp_sigmask, waitset);
1806 /*
1807 * We won't ever be woken up. Instead, our sleep will
1808 * be broken in lwpsignal().
1809 */
1810 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1811 if (timeout) {
1812 if (error == ERESTART) {
1813 /* can not restart a timeout wait. */
1814 error = EINTR;
1815 } else if (error == EAGAIN) {
1816 /* will calculate timeout by ourself. */
1817 error = 0;
1818 }
1819 }
1820 /* Retry ... */
1821 }
1822
1823 lp->lwp_sigmask = savedmask;
1824 if (sig) {
1825 error = 0;
1826 bzero(info, sizeof(*info));
1827 info->si_signo = sig;
1828 spin_lock(&lp->lwp_spin);
1829 lwp_delsig(lp, sig, 1); /* take the signal! */
1830 spin_unlock(&lp->lwp_spin);
1831
1832 if (sig == SIGKILL) {
1833 sigexit(lp, sig);
1834 /* NOT REACHED */
1835 }
1836 }
1837
1838 return (error);
1839 }
1840
1841 /*
1842 * MPALMOSTSAFE
1843 */
1844 int
1845 sys_sigtimedwait(struct sigtimedwait_args *uap)
1846 {
1847 struct timespec ts;
1848 struct timespec *timeout;
1849 sigset_t set;
1850 siginfo_t info;
1851 int error;
1852
1853 if (uap->timeout) {
1854 error = copyin(uap->timeout, &ts, sizeof(ts));
1855 if (error)
1856 return (error);
1857 timeout = &ts;
1858 } else {
1859 timeout = NULL;
1860 }
1861 error = copyin(uap->set, &set, sizeof(set));
1862 if (error)
1863 return (error);
1864 error = kern_sigtimedwait(set, &info, timeout);
1865 if (error)
1866 return (error);
1867 if (uap->info)
1868 error = copyout(&info, uap->info, sizeof(info));
1869 /* Repost if we got an error. */
1870 /*
1871 * XXX lwp
1872 *
1873 * This could transform a thread-specific signal to another
1874 * thread / process pending signal.
1875 */
1876 if (error) {
1877 ksignal(curproc, info.si_signo);
1878 } else {
1879 uap->sysmsg_result = info.si_signo;
1880 }
1881 return (error);
1882 }
1883
1884 /*
1885 * MPALMOSTSAFE
1886 */
1887 int
1888 sys_sigwaitinfo(struct sigwaitinfo_args *uap)
1889 {
1890 siginfo_t info;
1891 sigset_t set;
1892 int error;
1893
1894 error = copyin(uap->set, &set, sizeof(set));
1895 if (error)
1896 return (error);
1897 error = kern_sigtimedwait(set, &info, NULL);
1898 if (error)
1899 return (error);
1900 if (uap->info)
1901 error = copyout(&info, uap->info, sizeof(info));
1902 /* Repost if we got an error. */
1903 /*
1904 * XXX lwp
1905 *
1906 * This could transform a thread-specific signal to another
1907 * thread / process pending signal.
1908 */
1909 if (error) {
1910 ksignal(curproc, info.si_signo);
1911 } else {
1912 uap->sysmsg_result = info.si_signo;
1913 }
1914 return (error);
1915 }
1916
1917 /*
1918 * If the current process has received a signal that would interrupt a
1919 * system call, return EINTR or ERESTART as appropriate.
1920 */
1921 int
1922 iscaught(struct lwp *lp)
1923 {
1924 struct proc *p = lp->lwp_proc;
1925 int sig;
1926
1927 if (p) {
1928 if ((sig = CURSIG(lp)) != 0) {
1929 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1930 return (EINTR);
1931 return (ERESTART);
1932 }
1933 }
1934 return(EWOULDBLOCK);
1935 }
1936
1937 /*
1938 * If the current lwp/proc has received a signal (should be caught or cause
1939 * termination, should interrupt current syscall), return the signal number.
1940 * Stop signals with default action are processed immediately, then cleared;
1941 * they aren't returned. This is checked after each entry to the system for
1942 * a syscall or trap (though this can usually be done without calling issignal
1943 * by checking the pending signal masks in the CURSIG macro).
1944 *
1945 * This routine is called via CURSIG/__cursig. We will acquire and release
1946 * p->p_token but if the caller needs to interlock the test the caller must
1947 * also hold p->p_token.
1948 *
1949 * while (sig = CURSIG(curproc))
1950 * postsig(sig);
1951 */
1952 int
1953 issignal(struct lwp *lp, int maytrace, int *ptokp)
1954 {
1955 struct proc *p = lp->lwp_proc;
1956 sigset_t mask;
1957 int sig, prop;
1958 int haveptok;
1959
1960 for (;;) {
1961 int traced = (p->p_flags & P_TRACED) || (p->p_stops & S_SIG);
1962
1963 haveptok = 0;
1964
1965 /*
1966 * If this process is supposed to stop, stop this thread.
1967 */
1968 if (STOPLWP(p, lp)) {
1969 lwkt_gettoken(&p->p_token);
1970 tstop();
1971 lwkt_reltoken(&p->p_token);
1972 }
1973
1974 /*
1975 * Quick check without token
1976 */
1977 mask = lwp_sigpend(lp);
1978 SIGSETNAND(mask, lp->lwp_sigmask);
1979 if (p->p_flags & P_PPWAIT)
1980 SIG_STOPSIGMASK(mask);
1981 if (SIGISEMPTY(mask)) /* no signal to send */
1982 return (0);
1983
1984 /*
1985 * If the signal is a member of the process signal set
1986 * we need p_token (even if it is also a member of the
1987 * lwp signal set).
1988 */
1989 sig = sig_ffs(&mask);
1990 if (SIGISMEMBER(p->p_siglist, sig)) {
1991 /*
1992 * Recheck with token
1993 */
1994 haveptok = 1;
1995 lwkt_gettoken(&p->p_token);
1996
1997 mask = lwp_sigpend(lp);
1998 SIGSETNAND(mask, lp->lwp_sigmask);
1999 if (p->p_flags & P_PPWAIT)
2000 SIG_STOPSIGMASK(mask);
2001 if (SIGISEMPTY(mask)) { /* no signal to send */
2002 /* haveptok is TRUE */
2003 lwkt_reltoken(&p->p_token);
2004 return (0);
2005 }
2006 sig = sig_ffs(&mask);
2007 }
2008
2009 STOPEVENT(p, S_SIG, sig);
2010
2011 /*
2012 * We should see pending but ignored signals
2013 * only if P_TRACED was on when they were posted.
2014 */
2015 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
2016 spin_lock(&lp->lwp_spin);
2017 lwp_delsig(lp, sig, haveptok);
2018 spin_unlock(&lp->lwp_spin);
2019 if (haveptok)
2020 lwkt_reltoken(&p->p_token);
2021 continue;
2022 }
2023 if (maytrace &&
2024 (p->p_flags & P_TRACED) &&
2025 (p->p_flags & P_PPWAIT) == 0) {
2026 /*
2027 * If traced, always stop, and stay stopped until
2028 * released by the parent.
2029 *
2030 * NOTE: SSTOP may get cleared during the loop,
2031 * but we do not re-notify the parent if we have
2032 * to loop several times waiting for the parent
2033 * to let us continue.
2034 *
2035 * XXX not sure if this is still true
2036 */
2037 if (haveptok == 0) {
2038 lwkt_gettoken(&p->p_token);
2039 haveptok = 1;
2040 }
2041 p->p_xstat = sig;
2042 proc_stop(p, SSTOP);
2043 do {
2044 tstop();
2045 } while (!trace_req(p) && (p->p_flags & P_TRACED));
2046
2047 /*
2048 * If parent wants us to take the signal,
2049 * then it will leave it in p->p_xstat;
2050 * otherwise we just look for signals again.
2051 */
2052 spin_lock(&lp->lwp_spin);
2053 lwp_delsig(lp, sig, 1); /* clear old signal */
2054 spin_unlock(&lp->lwp_spin);
2055 sig = p->p_xstat;
2056 if (sig == 0) {
2057 /* haveptok is TRUE */
2058 lwkt_reltoken(&p->p_token);
2059 continue;
2060 }
2061
2062 /*
2063 * Put the new signal into p_siglist. If the
2064 * signal is being masked, look for other signals.
2065 *
2066 * XXX lwp might need a call to ksignal()
2067 */
2068 SIGADDSET_ATOMIC(p->p_siglist, sig);
2069 if (SIGISMEMBER(lp->lwp_sigmask, sig)) {
2070 /* haveptok is TRUE */
2071 lwkt_reltoken(&p->p_token);
2072 continue;
2073 }
2074
2075 /*
2076 * If the traced bit got turned off, go back up
2077 * to the top to rescan signals. This ensures
2078 * that p_sig* and ps_sigact are consistent.
2079 */
2080 if ((p->p_flags & P_TRACED) == 0) {
2081 /* haveptok is TRUE */
2082 lwkt_reltoken(&p->p_token);
2083 continue;
2084 }
2085 }
2086
2087 /*
2088 * p_token may be held here
2089 */
2090 prop = sigprop(sig);
2091
2092 /*
2093 * Decide whether the signal should be returned.
2094 * Return the signal's number, or fall through
2095 * to clear it from the pending mask.
2096 */
2097 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
2098 case (intptr_t)SIG_DFL:
2099 /*
2100 * Don't take default actions on system processes.
2101 */
2102 if (p->p_pid <= 1) {
2103 #ifdef DIAGNOSTIC
2104 /*
2105 * Are you sure you want to ignore SIGSEGV
2106 * in init? XXX
2107 */
2108 kprintf("Process (pid %lu) got signal %d\n",
2109 (u_long)p->p_pid, sig);
2110 #endif
2111 break; /* == ignore */
2112 }
2113
2114 /*
2115 * Handle the in-kernel checkpoint action
2116 */
2117 if (prop & SA_CKPT) {
2118 if (haveptok == 0) {
2119 lwkt_gettoken(&p->p_token);
2120 haveptok = 1;
2121 }
2122 checkpoint_signal_handler(lp);
2123 break;
2124 }
2125
2126 /*
2127 * If there is a pending stop signal to process
2128 * with default action, stop here,
2129 * then clear the signal. However,
2130 * if process is member of an orphaned
2131 * process group, ignore tty stop signals.
2132 */
2133 if (prop & SA_STOP) {
2134 if (haveptok == 0) {
2135 lwkt_gettoken(&p->p_token);
2136 haveptok = 1;
2137 }
2138 if (p->p_flags & P_TRACED ||
2139 (p->p_pgrp->pg_jobc == 0 &&
2140 prop & SA_TTYSTOP))
2141 break; /* == ignore */
2142 if ((p->p_flags & P_WEXIT) == 0) {
2143 p->p_xstat = sig;
2144 proc_stop(p, SSTOP);
2145 tstop();
2146 }
2147 break;
2148 } else if (prop & SA_IGNORE) {
2149 /*
2150 * Except for SIGCONT, shouldn't get here.
2151 * Default action is to ignore; drop it.
2152 */
2153 break; /* == ignore */
2154 } else {
2155 if (ptokp)
2156 *ptokp = haveptok;
2157 else if (haveptok)
2158 lwkt_reltoken(&p->p_token);
2159 return (sig);
2160 }
2161
2162 /*NOTREACHED*/
2163
2164 case (intptr_t)SIG_IGN:
2165 /*
2166 * Masking above should prevent us ever trying
2167 * to take action on an ignored signal other
2168 * than SIGCONT, unless process is traced.
2169 */
2170 if ((prop & SA_CONT) == 0 &&
2171 (p->p_flags & P_TRACED) == 0)
2172 kprintf("issignal\n");
2173 break; /* == ignore */
2174
2175 default:
2176 /*
2177 * This signal has an action, let
2178 * postsig() process it.
2179 */
2180 if (ptokp)
2181 *ptokp = haveptok;
2182 else if (haveptok)
2183 lwkt_reltoken(&p->p_token);
2184 return (sig);
2185 }
2186 spin_lock(&lp->lwp_spin);
2187 lwp_delsig(lp, sig, haveptok); /* take the signal! */
2188 spin_unlock(&lp->lwp_spin);
2189
2190 if (haveptok)
2191 lwkt_reltoken(&p->p_token);
2192 }
2193 /* NOTREACHED */
2194 }
2195
2196 /*
2197 * Take the action for the specified signal from the current set of
2198 * pending signals.
2199 *
2200 * haveptok indicates whether the caller is holding p->p_token. If the
2201 * caller is, we are responsible for releasing it.
2202 *
2203 * This routine can only be called from the top-level trap from usermode.
2204 * It is expecting to be able to modify the top-level stack frame.
2205 */
2206 void
2207 postsig(int sig, int haveptok)
2208 {
2209 struct lwp *lp = curthread->td_lwp;
2210 struct proc *p = lp->lwp_proc;
2211 struct sigacts *ps = p->p_sigacts;
2212 sig_t action;
2213 sigset_t returnmask;
2214 int code;
2215
2216 KASSERT(sig != 0, ("postsig"));
2217
2218 /*
2219 * If we are a virtual kernel running an emulated user process
2220 * context, switch back to the virtual kernel context before
2221 * trying to post the signal.
2222 */
2223 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
2224 struct trapframe *tf = lp->lwp_md.md_regs;
2225 tf->tf_trapno = 0;
2226 vkernel_trap(lp, tf);
2227 }
2228
2229 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
2230
2231 spin_lock(&lp->lwp_spin);
2232 lwp_delsig(lp, sig, haveptok);
2233 spin_unlock(&lp->lwp_spin);
2234 action = ps->ps_sigact[_SIG_IDX(sig)];
2235 #ifdef KTRACE
2236 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
2237 ktrpsig(lp, sig, action, lp->lwp_flags & LWP_OLDMASK ?
2238 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0);
2239 #endif
2240 /*
2241 * We don't need p_token after this point.
2242 */
2243 if (haveptok)
2244 lwkt_reltoken(&p->p_token);
2245
2246 STOPEVENT(p, S_SIG, sig);
2247
2248 if (action == SIG_DFL) {
2249 /*
2250 * Default action, where the default is to kill
2251 * the process. (Other cases were ignored above.)
2252 */
2253 sigexit(lp, sig);
2254 /* NOTREACHED */
2255 } else {
2256 /*
2257 * If we get here, the signal must be caught.
2258 */
2259 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig),
2260 ("postsig action"));
2261
2262 /*
2263 * Reset the signal handler if asked to
2264 */
2265 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
2266 /*
2267 * See kern_sigaction() for origin of this code.
2268 */
2269 SIGDELSET(p->p_sigcatch, sig);
2270 if (sig != SIGCONT &&
2271 sigprop(sig) & SA_IGNORE)
2272 SIGADDSET(p->p_sigignore, sig);
2273 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
2274 }
2275
2276 /*
2277 * Set the signal mask and calculate the mask to restore
2278 * when the signal function returns.
2279 *
2280 * Special case: user has done a sigsuspend. Here the
2281 * current mask is not of interest, but rather the
2282 * mask from before the sigsuspend is what we want
2283 * restored after the signal processing is completed.
2284 */
2285 if (lp->lwp_flags & LWP_OLDMASK) {
2286 returnmask = lp->lwp_oldsigmask;
2287 lp->lwp_flags &= ~LWP_OLDMASK;
2288 } else {
2289 returnmask = lp->lwp_sigmask;
2290 }
2291
2292 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
2293 if (!SIGISMEMBER(ps->ps_signodefer, sig))
2294 SIGADDSET(lp->lwp_sigmask, sig);
2295
2296 lp->lwp_ru.ru_nsignals++;
2297 if (lp->lwp_sig != sig) {
2298 code = 0;
2299 } else {
2300 code = lp->lwp_code;
2301 lp->lwp_code = 0;
2302 lp->lwp_sig = 0;
2303 }
2304 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
2305 }
2306 }
2307
2308 /*
2309 * Kill the current process for stated reason.
2310 */
2311 void
2312 killproc(struct proc *p, char *why)
2313 {
2314 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n",
2315 p->p_pid, p->p_comm,
2316 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
2317 ksignal(p, SIGKILL);
2318 }
2319
2320 /*
2321 * Force the current process to exit with the specified signal, dumping core
2322 * if appropriate. We bypass the normal tests for masked and caught signals,
2323 * allowing unrecoverable failures to terminate the process without changing
2324 * signal state. Mark the accounting record with the signal termination.
2325 * If dumping core, save the signal number for the debugger. Calls exit and
2326 * does not return.
2327 *
2328 * This routine does not return.
2329 */
2330 void
2331 sigexit(struct lwp *lp, int sig)
2332 {
2333 struct proc *p = lp->lwp_proc;
2334
2335 lwkt_gettoken(&p->p_token);
2336 p->p_acflag |= AXSIG;
2337 if (sigprop(sig) & SA_CORE) {
2338 lp->lwp_sig = sig;
2339
2340 /*
2341 * All threads must be stopped before we can safely coredump.
2342 * Stop threads using SCORE, which cannot be overridden.
2343 */
2344 if (p->p_stat != SCORE) {
2345 proc_stop(p, SCORE);
2346 proc_stopwait(p);
2347
2348 if (coredump(lp, sig) == 0)
2349 sig |= WCOREFLAG;
2350 p->p_stat = SSTOP;
2351 }
2352
2353 /*
2354 * Log signals which would cause core dumps
2355 * (Log as LOG_INFO to appease those who don't want
2356 * these messages.)
2357 * XXX : Todo, as well as euid, write out ruid too
2358 */
2359 if (kern_logsigexit) {
2360 log(LOG_INFO,
2361 "pid %d (%s), uid %d: exited on signal %d%s\n",
2362 p->p_pid, p->p_comm,
2363 p->p_ucred ? p->p_ucred->cr_uid : -1,
2364 sig &~ WCOREFLAG,
2365 sig & WCOREFLAG ? " (core dumped)" : "");
2366 }
2367 }
2368 lwkt_reltoken(&p->p_token);
2369 exit1(W_EXITCODE(0, sig));
2370 /* NOTREACHED */
2371 }
2372
2373 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
2374 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
2375 sizeof(corefilename), "process corefile name format string");
2376
2377 /*
2378 * expand_name(name, uid, pid)
2379 * Expand the name described in corefilename, using name, uid, and pid.
2380 * corefilename is a kprintf-like string, with three format specifiers:
2381 * %N name of process ("name")
2382 * %P process id (pid)
2383 * %U user id (uid)
2384 * For example, "%N.core" is the default; they can be disabled completely
2385 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
2386 * This is controlled by the sysctl variable kern.corefile (see above).
2387 */
2388
2389 static char *
2390 expand_name(const char *name, uid_t uid, pid_t pid)
2391 {
2392 char *temp;
2393 char buf[11]; /* Buffer for pid/uid -- max 4B */
2394 int i, n;
2395 char *format = corefilename;
2396 size_t namelen;
2397
2398 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
2399 if (temp == NULL)
2400 return NULL;
2401 namelen = strlen(name);
2402 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
2403 int l;
2404 switch (format[i]) {
2405 case '%': /* Format character */
2406 i++;
2407 switch (format[i]) {
2408 case '%':
2409 temp[n++] = '%';
2410 break;
2411 case 'N': /* process name */
2412 if ((n + namelen) > MAXPATHLEN) {
2413 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2414 pid, name, uid, temp, name);
2415 kfree(temp, M_TEMP);
2416 return NULL;
2417 }
2418 memcpy(temp+n, name, namelen);
2419 n += namelen;
2420 break;
2421 case 'P': /* process id */
2422 l = ksprintf(buf, "%u", pid);
2423 if ((n + l) > MAXPATHLEN) {
2424 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2425 pid, name, uid, temp, name);
2426 kfree(temp, M_TEMP);
2427 return NULL;
2428 }
2429 memcpy(temp+n, buf, l);
2430 n += l;
2431 break;
2432 case 'U': /* user id */
2433 l = ksprintf(buf, "%u", uid);
2434 if ((n + l) > MAXPATHLEN) {
2435 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2436 pid, name, uid, temp, name);
2437 kfree(temp, M_TEMP);
2438 return NULL;
2439 }
2440 memcpy(temp+n, buf, l);
2441 n += l;
2442 break;
2443 default:
2444 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
2445 }
2446 break;
2447 default:
2448 temp[n++] = format[i];
2449 }
2450 }
2451 temp[n] = '\0';
2452 return temp;
2453 }
2454
2455 /*
2456 * Dump a process' core. The main routine does some
2457 * policy checking, and creates the name of the coredump;
2458 * then it passes on a vnode and a size limit to the process-specific
2459 * coredump routine if there is one; if there _is not_ one, it returns
2460 * ENOSYS; otherwise it returns the error from the process-specific routine.
2461 *
2462 * The parameter `lp' is the lwp which triggered the coredump.
2463 */
2464
2465 static int
2466 coredump(struct lwp *lp, int sig)
2467 {
2468 struct proc *p = lp->lwp_proc;
2469 struct vnode *vp;
2470 struct ucred *cred = p->p_ucred;
2471 struct flock lf;
2472 struct nlookupdata nd;
2473 struct vattr vattr;
2474 int error, error1;
2475 char *name; /* name of corefile */
2476 off_t limit;
2477
2478 STOPEVENT(p, S_CORE, 0);
2479
2480 if (((sugid_coredump == 0) && p->p_flags & P_SUGID) || do_coredump == 0)
2481 return (EFAULT);
2482
2483 /*
2484 * Note that the bulk of limit checking is done after
2485 * the corefile is created. The exception is if the limit
2486 * for corefiles is 0, in which case we don't bother
2487 * creating the corefile at all. This layout means that
2488 * a corefile is truncated instead of not being created,
2489 * if it is larger than the limit.
2490 */
2491 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
2492 if (limit == 0)
2493 return EFBIG;
2494
2495 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
2496 if (name == NULL)
2497 return (EINVAL);
2498 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
2499 if (error == 0)
2500 error = vn_open(&nd, NULL,
2501 O_CREAT | FWRITE | O_NOFOLLOW,
2502 S_IRUSR | S_IWUSR);
2503 kfree(name, M_TEMP);
2504 if (error) {
2505 nlookup_done(&nd);
2506 return (error);
2507 }
2508 vp = nd.nl_open_vp;
2509 nd.nl_open_vp = NULL;
2510 nlookup_done(&nd);
2511
2512 vn_unlock(vp);
2513 lf.l_whence = SEEK_SET;
2514 lf.l_start = 0;
2515 lf.l_len = 0;
2516 lf.l_type = F_WRLCK;
2517 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
2518 if (error)
2519 goto out2;
2520
2521 /* Don't dump to non-regular files or files with links. */
2522 if (vp->v_type != VREG ||
2523 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
2524 error = EFAULT;
2525 goto out1;
2526 }
2527
2528 /* Don't dump to files current user does not own */
2529 if (vattr.va_uid != p->p_ucred->cr_uid) {
2530 error = EFAULT;
2531 goto out1;
2532 }
2533
2534 VATTR_NULL(&vattr);
2535 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2536 vattr.va_size = 0;
2537 VOP_SETATTR(vp, &vattr, cred);
2538 p->p_acflag |= ACORE;
2539 vn_unlock(vp);
2540
2541 error = p->p_sysent->sv_coredump ?
2542 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS;
2543
2544 out1:
2545 lf.l_type = F_UNLCK;
2546 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
2547 out2:
2548 error1 = vn_close(vp, FWRITE, NULL);
2549 if (error == 0)
2550 error = error1;
2551 return (error);
2552 }
2553
2554 /*
2555 * Nonexistent system call-- signal process (may want to handle it).
2556 * Flag error in case process won't see signal immediately (blocked or ignored).
2557 *
2558 * MPALMOSTSAFE
2559 */
2560 /* ARGSUSED */
2561 int
2562 sys_nosys(struct nosys_args *args)
2563 {
2564 lwpsignal(curproc, curthread->td_lwp, SIGSYS);
2565 return (EINVAL);
2566 }
2567
2568 /*
2569 * Send a SIGIO or SIGURG signal to a process or process group using
2570 * stored credentials rather than those of the current process.
2571 */
2572 void
2573 pgsigio(struct sigio *sigio, int sig, int checkctty)
2574 {
2575 if (sigio == NULL)
2576 return;
2577
2578 if (sigio->sio_pgid > 0) {
2579 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
2580 sigio->sio_proc))
2581 ksignal(sigio->sio_proc, sig);
2582 } else if (sigio->sio_pgid < 0) {
2583 struct proc *p;
2584 struct pgrp *pg = sigio->sio_pgrp;
2585
2586 /*
2587 * Must interlock all signals against fork
2588 */
2589 pgref(pg);
2590 lockmgr(&pg->pg_lock, LK_EXCLUSIVE);
2591 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
2592 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
2593 (checkctty == 0 || (p->p_flags & P_CONTROLT)))
2594 ksignal(p, sig);
2595 }
2596 lockmgr(&pg->pg_lock, LK_RELEASE);
2597 pgrel(pg);
2598 }
2599 }
2600
2601 static int
2602 filt_sigattach(struct knote *kn)
2603 {
2604 struct proc *p = curproc;
2605
2606 kn->kn_ptr.p_proc = p;
2607 kn->kn_flags |= EV_CLEAR; /* automatically set */
2608
2609 /* XXX lock the proc here while adding to the list? */
2610 knote_insert(&p->p_klist, kn);
2611
2612 return (0);
2613 }
2614
2615 static void
2616 filt_sigdetach(struct knote *kn)
2617 {
2618 struct proc *p = kn->kn_ptr.p_proc;
2619
2620 knote_remove(&p->p_klist, kn);
2621 }
2622
2623 /*
2624 * signal knotes are shared with proc knotes, so we apply a mask to
2625 * the hint in order to differentiate them from process hints. This
2626 * could be avoided by using a signal-specific knote list, but probably
2627 * isn't worth the trouble.
2628 */
2629 static int
2630 filt_signal(struct knote *kn, long hint)
2631 {
2632 if (hint & NOTE_SIGNAL) {
2633 hint &= ~NOTE_SIGNAL;
2634
2635 if (kn->kn_id == hint)
2636 kn->kn_data++;
2637 }
2638 return (kn->kn_data != 0);
2639 }
DragonFly BSD