xref: /netbsd-src/sys/kern/kern_time.c (revision 2d8e86c2f207da6fbbd50f11b6f33765ebdfa0e9)
1 /*	$NetBSD: kern_time.c,v 1.199 2019/08/07 07:22:12 mrg Exp $	*/
2 
3 /*-
4  * Copyright (c) 2000, 2004, 2005, 2007, 2008, 2009 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Christopher G. Demetriou, and by Andrew Doran.
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  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 /*
33  * Copyright (c) 1982, 1986, 1989, 1993
34  *	The Regents of the University of California.  All rights reserved.
35  *
36  * Redistribution and use in source and binary forms, with or without
37  * modification, are permitted provided that the following conditions
38  * are met:
39  * 1. Redistributions of source code must retain the above copyright
40  *    notice, this list of conditions and the following disclaimer.
41  * 2. Redistributions in binary form must reproduce the above copyright
42  *    notice, this list of conditions and the following disclaimer in the
43  *    documentation and/or other materials provided with the distribution.
44  * 3. Neither the name of the University nor the names of its contributors
45  *    may be used to endorse or promote products derived from this software
46  *    without specific prior written permission.
47  *
48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58  * SUCH DAMAGE.
59  *
60  *	@(#)kern_time.c	8.4 (Berkeley) 5/26/95
61  */
62 
63 #include <sys/cdefs.h>
64 __KERNEL_RCSID(0, "$NetBSD: kern_time.c,v 1.199 2019/08/07 07:22:12 mrg Exp $");
65 
66 #include <sys/param.h>
67 #include <sys/resourcevar.h>
68 #include <sys/kernel.h>
69 #include <sys/systm.h>
70 #include <sys/proc.h>
71 #include <sys/vnode.h>
72 #include <sys/signalvar.h>
73 #include <sys/syslog.h>
74 #include <sys/timetc.h>
75 #include <sys/timex.h>
76 #include <sys/kauth.h>
77 #include <sys/mount.h>
78 #include <sys/syscallargs.h>
79 #include <sys/cpu.h>
80 
81 static void	timer_intr(void *);
82 static void	itimerfire(struct ptimer *);
83 static void	itimerfree(struct ptimers *, int);
84 
85 kmutex_t	timer_lock;
86 
87 static void	*timer_sih;
88 static TAILQ_HEAD(, ptimer) timer_queue;
89 
90 struct pool ptimer_pool, ptimers_pool;
91 
92 #define	CLOCK_VIRTUAL_P(clockid)	\
93 	((clockid) == CLOCK_VIRTUAL || (clockid) == CLOCK_PROF)
94 
95 CTASSERT(ITIMER_REAL == CLOCK_REALTIME);
96 CTASSERT(ITIMER_VIRTUAL == CLOCK_VIRTUAL);
97 CTASSERT(ITIMER_PROF == CLOCK_PROF);
98 CTASSERT(ITIMER_MONOTONIC == CLOCK_MONOTONIC);
99 
100 #define	DELAYTIMER_MAX	32
101 
102 /*
103  * Initialize timekeeping.
104  */
105 void
106 time_init(void)
107 {
108 
109 	pool_init(&ptimer_pool, sizeof(struct ptimer), 0, 0, 0, "ptimerpl",
110 	    &pool_allocator_nointr, IPL_NONE);
111 	pool_init(&ptimers_pool, sizeof(struct ptimers), 0, 0, 0, "ptimerspl",
112 	    &pool_allocator_nointr, IPL_NONE);
113 }
114 
115 void
116 time_init2(void)
117 {
118 
119 	TAILQ_INIT(&timer_queue);
120 	mutex_init(&timer_lock, MUTEX_DEFAULT, IPL_SCHED);
121 	timer_sih = softint_establish(SOFTINT_CLOCK | SOFTINT_MPSAFE,
122 	    timer_intr, NULL);
123 }
124 
125 /* Time of day and interval timer support.
126  *
127  * These routines provide the kernel entry points to get and set
128  * the time-of-day and per-process interval timers.  Subroutines
129  * here provide support for adding and subtracting timeval structures
130  * and decrementing interval timers, optionally reloading the interval
131  * timers when they expire.
132  */
133 
134 /* This function is used by clock_settime and settimeofday */
135 static int
136 settime1(struct proc *p, const struct timespec *ts, bool check_kauth)
137 {
138 	struct timespec delta, now;
139 	int s;
140 
141 	/* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */
142 	s = splclock();
143 	nanotime(&now);
144 	timespecsub(ts, &now, &delta);
145 
146 	if (check_kauth && kauth_authorize_system(kauth_cred_get(),
147 	    KAUTH_SYSTEM_TIME, KAUTH_REQ_SYSTEM_TIME_SYSTEM, __UNCONST(ts),
148 	    &delta, KAUTH_ARG(check_kauth ? false : true)) != 0) {
149 		splx(s);
150 		return (EPERM);
151 	}
152 
153 #ifdef notyet
154 	if ((delta.tv_sec < 86400) && securelevel > 0) { /* XXX elad - notyet */
155 		splx(s);
156 		return (EPERM);
157 	}
158 #endif
159 
160 	tc_setclock(ts);
161 
162 	timespecadd(&boottime, &delta, &boottime);
163 
164 	resettodr();
165 	splx(s);
166 
167 	return (0);
168 }
169 
170 int
171 settime(struct proc *p, struct timespec *ts)
172 {
173 	return (settime1(p, ts, true));
174 }
175 
176 /* ARGSUSED */
177 int
178 sys___clock_gettime50(struct lwp *l,
179     const struct sys___clock_gettime50_args *uap, register_t *retval)
180 {
181 	/* {
182 		syscallarg(clockid_t) clock_id;
183 		syscallarg(struct timespec *) tp;
184 	} */
185 	int error;
186 	struct timespec ats;
187 
188 	error = clock_gettime1(SCARG(uap, clock_id), &ats);
189 	if (error != 0)
190 		return error;
191 
192 	return copyout(&ats, SCARG(uap, tp), sizeof(ats));
193 }
194 
195 /* ARGSUSED */
196 int
197 sys___clock_settime50(struct lwp *l,
198     const struct sys___clock_settime50_args *uap, register_t *retval)
199 {
200 	/* {
201 		syscallarg(clockid_t) clock_id;
202 		syscallarg(const struct timespec *) tp;
203 	} */
204 	int error;
205 	struct timespec ats;
206 
207 	if ((error = copyin(SCARG(uap, tp), &ats, sizeof(ats))) != 0)
208 		return error;
209 
210 	return clock_settime1(l->l_proc, SCARG(uap, clock_id), &ats, true);
211 }
212 
213 
214 int
215 clock_settime1(struct proc *p, clockid_t clock_id, const struct timespec *tp,
216     bool check_kauth)
217 {
218 	int error;
219 
220 	switch (clock_id) {
221 	case CLOCK_REALTIME:
222 		if ((error = settime1(p, tp, check_kauth)) != 0)
223 			return (error);
224 		break;
225 	case CLOCK_MONOTONIC:
226 		return (EINVAL);	/* read-only clock */
227 	default:
228 		return (EINVAL);
229 	}
230 
231 	return 0;
232 }
233 
234 int
235 sys___clock_getres50(struct lwp *l, const struct sys___clock_getres50_args *uap,
236     register_t *retval)
237 {
238 	/* {
239 		syscallarg(clockid_t) clock_id;
240 		syscallarg(struct timespec *) tp;
241 	} */
242 	struct timespec ts;
243 	int error;
244 
245 	if ((error = clock_getres1(SCARG(uap, clock_id), &ts)) != 0)
246 		return error;
247 
248 	if (SCARG(uap, tp))
249 		error = copyout(&ts, SCARG(uap, tp), sizeof(ts));
250 
251 	return error;
252 }
253 
254 int
255 clock_getres1(clockid_t clock_id, struct timespec *ts)
256 {
257 
258 	switch (clock_id) {
259 	case CLOCK_REALTIME:
260 	case CLOCK_MONOTONIC:
261 		ts->tv_sec = 0;
262 		if (tc_getfrequency() > 1000000000)
263 			ts->tv_nsec = 1;
264 		else
265 			ts->tv_nsec = 1000000000 / tc_getfrequency();
266 		break;
267 	default:
268 		return EINVAL;
269 	}
270 
271 	return 0;
272 }
273 
274 /* ARGSUSED */
275 int
276 sys___nanosleep50(struct lwp *l, const struct sys___nanosleep50_args *uap,
277     register_t *retval)
278 {
279 	/* {
280 		syscallarg(struct timespec *) rqtp;
281 		syscallarg(struct timespec *) rmtp;
282 	} */
283 	struct timespec rmt, rqt;
284 	int error, error1;
285 
286 	error = copyin(SCARG(uap, rqtp), &rqt, sizeof(struct timespec));
287 	if (error)
288 		return (error);
289 
290 	error = nanosleep1(l, CLOCK_MONOTONIC, 0, &rqt,
291 	    SCARG(uap, rmtp) ? &rmt : NULL);
292 	if (SCARG(uap, rmtp) == NULL || (error != 0 && error != EINTR))
293 		return error;
294 
295 	error1 = copyout(&rmt, SCARG(uap, rmtp), sizeof(rmt));
296 	return error1 ? error1 : error;
297 }
298 
299 /* ARGSUSED */
300 int
301 sys_clock_nanosleep(struct lwp *l, const struct sys_clock_nanosleep_args *uap,
302     register_t *retval)
303 {
304 	/* {
305 		syscallarg(clockid_t) clock_id;
306 		syscallarg(int) flags;
307 		syscallarg(struct timespec *) rqtp;
308 		syscallarg(struct timespec *) rmtp;
309 	} */
310 	struct timespec rmt, rqt;
311 	int error, error1;
312 
313 	error = copyin(SCARG(uap, rqtp), &rqt, sizeof(struct timespec));
314 	if (error)
315 		goto out;
316 
317 	error = nanosleep1(l, SCARG(uap, clock_id), SCARG(uap, flags), &rqt,
318 	    SCARG(uap, rmtp) ? &rmt : NULL);
319 	if (SCARG(uap, rmtp) == NULL || (error != 0 && error != EINTR))
320 		goto out;
321 
322 	if ((SCARG(uap, flags) & TIMER_ABSTIME) == 0 &&
323 	    (error1 = copyout(&rmt, SCARG(uap, rmtp), sizeof(rmt))) != 0)
324 		error = error1;
325 out:
326 	*retval = error;
327 	return 0;
328 }
329 
330 int
331 nanosleep1(struct lwp *l, clockid_t clock_id, int flags, struct timespec *rqt,
332     struct timespec *rmt)
333 {
334 	struct timespec rmtstart;
335 	int error, timo;
336 
337 	if ((error = ts2timo(clock_id, flags, rqt, &timo, &rmtstart)) != 0) {
338 		if (error == ETIMEDOUT) {
339 			error = 0;
340 			if (rmt != NULL)
341 				rmt->tv_sec = rmt->tv_nsec = 0;
342 		}
343 		return error;
344 	}
345 
346 	/*
347 	 * Avoid inadvertently sleeping forever
348 	 */
349 	if (timo == 0)
350 		timo = 1;
351 again:
352 	error = kpause("nanoslp", true, timo, NULL);
353 	if (error == EWOULDBLOCK)
354 		error = 0;
355 	if (rmt != NULL || error == 0) {
356 		struct timespec rmtend;
357 		struct timespec t0;
358 		struct timespec *t;
359 
360 		(void)clock_gettime1(clock_id, &rmtend);
361 		t = (rmt != NULL) ? rmt : &t0;
362 		if (flags & TIMER_ABSTIME) {
363 			timespecsub(rqt, &rmtend, t);
364 		} else {
365 			timespecsub(&rmtend, &rmtstart, t);
366 			timespecsub(rqt, t, t);
367 		}
368 		if (t->tv_sec < 0)
369 			timespecclear(t);
370 		if (error == 0) {
371 			timo = tstohz(t);
372 			if (timo > 0)
373 				goto again;
374 		}
375 	}
376 
377 	if (error == ERESTART)
378 		error = EINTR;
379 
380 	return error;
381 }
382 
383 int
384 sys_clock_getcpuclockid2(struct lwp *l,
385     const struct sys_clock_getcpuclockid2_args *uap,
386     register_t *retval)
387 {
388 	/* {
389 		syscallarg(idtype_t idtype;
390 		syscallarg(id_t id);
391 		syscallarg(clockid_t *)clock_id;
392 	} */
393 	pid_t pid;
394 	lwpid_t lid;
395 	clockid_t clock_id;
396 	id_t id = SCARG(uap, id);
397 
398 	switch (SCARG(uap, idtype)) {
399 	case P_PID:
400 		pid = id == 0 ? l->l_proc->p_pid : id;
401 		clock_id = CLOCK_PROCESS_CPUTIME_ID | pid;
402 		break;
403 	case P_LWPID:
404 		lid = id == 0 ? l->l_lid : id;
405 		clock_id = CLOCK_THREAD_CPUTIME_ID | lid;
406 		break;
407 	default:
408 		return EINVAL;
409 	}
410 	return copyout(&clock_id, SCARG(uap, clock_id), sizeof(clock_id));
411 }
412 
413 /* ARGSUSED */
414 int
415 sys___gettimeofday50(struct lwp *l, const struct sys___gettimeofday50_args *uap,
416     register_t *retval)
417 {
418 	/* {
419 		syscallarg(struct timeval *) tp;
420 		syscallarg(void *) tzp;		really "struct timezone *";
421 	} */
422 	struct timeval atv;
423 	int error = 0;
424 	struct timezone tzfake;
425 
426 	if (SCARG(uap, tp)) {
427 		memset(&atv, 0, sizeof(atv));
428 		microtime(&atv);
429 		error = copyout(&atv, SCARG(uap, tp), sizeof(atv));
430 		if (error)
431 			return (error);
432 	}
433 	if (SCARG(uap, tzp)) {
434 		/*
435 		 * NetBSD has no kernel notion of time zone, so we just
436 		 * fake up a timezone struct and return it if demanded.
437 		 */
438 		tzfake.tz_minuteswest = 0;
439 		tzfake.tz_dsttime = 0;
440 		error = copyout(&tzfake, SCARG(uap, tzp), sizeof(tzfake));
441 	}
442 	return (error);
443 }
444 
445 /* ARGSUSED */
446 int
447 sys___settimeofday50(struct lwp *l, const struct sys___settimeofday50_args *uap,
448     register_t *retval)
449 {
450 	/* {
451 		syscallarg(const struct timeval *) tv;
452 		syscallarg(const void *) tzp; really "const struct timezone *";
453 	} */
454 
455 	return settimeofday1(SCARG(uap, tv), true, SCARG(uap, tzp), l, true);
456 }
457 
458 int
459 settimeofday1(const struct timeval *utv, bool userspace,
460     const void *utzp, struct lwp *l, bool check_kauth)
461 {
462 	struct timeval atv;
463 	struct timespec ts;
464 	int error;
465 
466 	/* Verify all parameters before changing time. */
467 
468 	/*
469 	 * NetBSD has no kernel notion of time zone, and only an
470 	 * obsolete program would try to set it, so we log a warning.
471 	 */
472 	if (utzp)
473 		log(LOG_WARNING, "pid %d attempted to set the "
474 		    "(obsolete) kernel time zone\n", l->l_proc->p_pid);
475 
476 	if (utv == NULL)
477 		return 0;
478 
479 	if (userspace) {
480 		if ((error = copyin(utv, &atv, sizeof(atv))) != 0)
481 			return error;
482 		utv = &atv;
483 	}
484 
485 	TIMEVAL_TO_TIMESPEC(utv, &ts);
486 	return settime1(l->l_proc, &ts, check_kauth);
487 }
488 
489 int	time_adjusted;			/* set if an adjustment is made */
490 
491 /* ARGSUSED */
492 int
493 sys___adjtime50(struct lwp *l, const struct sys___adjtime50_args *uap,
494     register_t *retval)
495 {
496 	/* {
497 		syscallarg(const struct timeval *) delta;
498 		syscallarg(struct timeval *) olddelta;
499 	} */
500 	int error;
501 	struct timeval atv, oldatv;
502 
503 	if ((error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_TIME,
504 	    KAUTH_REQ_SYSTEM_TIME_ADJTIME, NULL, NULL, NULL)) != 0)
505 		return error;
506 
507 	if (SCARG(uap, delta)) {
508 		error = copyin(SCARG(uap, delta), &atv,
509 		    sizeof(*SCARG(uap, delta)));
510 		if (error)
511 			return (error);
512 	}
513 	adjtime1(SCARG(uap, delta) ? &atv : NULL,
514 	    SCARG(uap, olddelta) ? &oldatv : NULL, l->l_proc);
515 	if (SCARG(uap, olddelta))
516 		error = copyout(&oldatv, SCARG(uap, olddelta),
517 		    sizeof(*SCARG(uap, olddelta)));
518 	return error;
519 }
520 
521 void
522 adjtime1(const struct timeval *delta, struct timeval *olddelta, struct proc *p)
523 {
524 	extern int64_t time_adjtime;  /* in kern_ntptime.c */
525 
526 	if (olddelta) {
527 		memset(olddelta, 0, sizeof(*olddelta));
528 		mutex_spin_enter(&timecounter_lock);
529 		olddelta->tv_sec = time_adjtime / 1000000;
530 		olddelta->tv_usec = time_adjtime % 1000000;
531 		if (olddelta->tv_usec < 0) {
532 			olddelta->tv_usec += 1000000;
533 			olddelta->tv_sec--;
534 		}
535 		mutex_spin_exit(&timecounter_lock);
536 	}
537 
538 	if (delta) {
539 		mutex_spin_enter(&timecounter_lock);
540 		time_adjtime = delta->tv_sec * 1000000 + delta->tv_usec;
541 
542 		if (time_adjtime) {
543 			/* We need to save the system time during shutdown */
544 			time_adjusted |= 1;
545 		}
546 		mutex_spin_exit(&timecounter_lock);
547 	}
548 }
549 
550 /*
551  * Interval timer support. Both the BSD getitimer() family and the POSIX
552  * timer_*() family of routines are supported.
553  *
554  * All timers are kept in an array pointed to by p_timers, which is
555  * allocated on demand - many processes don't use timers at all. The
556  * first four elements in this array are reserved for the BSD timers:
557  * element 0 is ITIMER_REAL, element 1 is ITIMER_VIRTUAL, element
558  * 2 is ITIMER_PROF, and element 3 is ITIMER_MONOTONIC. The rest may be
559  * allocated by the timer_create() syscall.
560  *
561  * Realtime timers are kept in the ptimer structure as an absolute
562  * time; virtual time timers are kept as a linked list of deltas.
563  * Virtual time timers are processed in the hardclock() routine of
564  * kern_clock.c.  The real time timer is processed by a callout
565  * routine, called from the softclock() routine.  Since a callout may
566  * be delayed in real time due to interrupt processing in the system,
567  * it is possible for the real time timeout routine (realtimeexpire,
568  * given below), to be delayed in real time past when it is supposed
569  * to occur.  It does not suffice, therefore, to reload the real timer
570  * .it_value from the real time timers .it_interval.  Rather, we
571  * compute the next time in absolute time the timer should go off.  */
572 
573 /* Allocate a POSIX realtime timer. */
574 int
575 sys_timer_create(struct lwp *l, const struct sys_timer_create_args *uap,
576     register_t *retval)
577 {
578 	/* {
579 		syscallarg(clockid_t) clock_id;
580 		syscallarg(struct sigevent *) evp;
581 		syscallarg(timer_t *) timerid;
582 	} */
583 
584 	return timer_create1(SCARG(uap, timerid), SCARG(uap, clock_id),
585 	    SCARG(uap, evp), copyin, l);
586 }
587 
588 int
589 timer_create1(timer_t *tid, clockid_t id, struct sigevent *evp,
590     copyin_t fetch_event, struct lwp *l)
591 {
592 	int error;
593 	timer_t timerid;
594 	struct ptimers *pts;
595 	struct ptimer *pt;
596 	struct proc *p;
597 
598 	p = l->l_proc;
599 
600 	if ((u_int)id > CLOCK_MONOTONIC)
601 		return (EINVAL);
602 
603 	if ((pts = p->p_timers) == NULL)
604 		pts = timers_alloc(p);
605 
606 	pt = pool_get(&ptimer_pool, PR_WAITOK | PR_ZERO);
607 	if (evp != NULL) {
608 		if (((error =
609 		    (*fetch_event)(evp, &pt->pt_ev, sizeof(pt->pt_ev))) != 0) ||
610 		    ((pt->pt_ev.sigev_notify < SIGEV_NONE) ||
611 			(pt->pt_ev.sigev_notify > SIGEV_SA)) ||
612 			(pt->pt_ev.sigev_notify == SIGEV_SIGNAL &&
613 			 (pt->pt_ev.sigev_signo <= 0 ||
614 			  pt->pt_ev.sigev_signo >= NSIG))) {
615 			pool_put(&ptimer_pool, pt);
616 			return (error ? error : EINVAL);
617 		}
618 	}
619 
620 	/* Find a free timer slot, skipping those reserved for setitimer(). */
621 	mutex_spin_enter(&timer_lock);
622 	for (timerid = TIMER_MIN; timerid < TIMER_MAX; timerid++)
623 		if (pts->pts_timers[timerid] == NULL)
624 			break;
625 	if (timerid == TIMER_MAX) {
626 		mutex_spin_exit(&timer_lock);
627 		pool_put(&ptimer_pool, pt);
628 		return EAGAIN;
629 	}
630 	if (evp == NULL) {
631 		pt->pt_ev.sigev_notify = SIGEV_SIGNAL;
632 		switch (id) {
633 		case CLOCK_REALTIME:
634 		case CLOCK_MONOTONIC:
635 			pt->pt_ev.sigev_signo = SIGALRM;
636 			break;
637 		case CLOCK_VIRTUAL:
638 			pt->pt_ev.sigev_signo = SIGVTALRM;
639 			break;
640 		case CLOCK_PROF:
641 			pt->pt_ev.sigev_signo = SIGPROF;
642 			break;
643 		}
644 		pt->pt_ev.sigev_value.sival_int = timerid;
645 	}
646 	pt->pt_info.ksi_signo = pt->pt_ev.sigev_signo;
647 	pt->pt_info.ksi_errno = 0;
648 	pt->pt_info.ksi_code = 0;
649 	pt->pt_info.ksi_pid = p->p_pid;
650 	pt->pt_info.ksi_uid = kauth_cred_getuid(l->l_cred);
651 	pt->pt_info.ksi_value = pt->pt_ev.sigev_value;
652 	pt->pt_type = id;
653 	pt->pt_proc = p;
654 	pt->pt_overruns = 0;
655 	pt->pt_poverruns = 0;
656 	pt->pt_entry = timerid;
657 	pt->pt_queued = false;
658 	timespecclear(&pt->pt_time.it_value);
659 	if (!CLOCK_VIRTUAL_P(id))
660 		callout_init(&pt->pt_ch, CALLOUT_MPSAFE);
661 	else
662 		pt->pt_active = 0;
663 
664 	pts->pts_timers[timerid] = pt;
665 	mutex_spin_exit(&timer_lock);
666 
667 	return copyout(&timerid, tid, sizeof(timerid));
668 }
669 
670 /* Delete a POSIX realtime timer */
671 int
672 sys_timer_delete(struct lwp *l, const struct sys_timer_delete_args *uap,
673     register_t *retval)
674 {
675 	/* {
676 		syscallarg(timer_t) timerid;
677 	} */
678 	struct proc *p = l->l_proc;
679 	timer_t timerid;
680 	struct ptimers *pts;
681 	struct ptimer *pt, *ptn;
682 
683 	timerid = SCARG(uap, timerid);
684 	pts = p->p_timers;
685 
686 	if (pts == NULL || timerid < 2 || timerid >= TIMER_MAX)
687 		return (EINVAL);
688 
689 	mutex_spin_enter(&timer_lock);
690 	if ((pt = pts->pts_timers[timerid]) == NULL) {
691 		mutex_spin_exit(&timer_lock);
692 		return (EINVAL);
693 	}
694 	if (CLOCK_VIRTUAL_P(pt->pt_type)) {
695 		if (pt->pt_active) {
696 			ptn = LIST_NEXT(pt, pt_list);
697 			LIST_REMOVE(pt, pt_list);
698 			for ( ; ptn; ptn = LIST_NEXT(ptn, pt_list))
699 				timespecadd(&pt->pt_time.it_value,
700 				    &ptn->pt_time.it_value,
701 				    &ptn->pt_time.it_value);
702 			pt->pt_active = 0;
703 		}
704 	}
705 
706 	/* Free the timer and release the lock.  */
707 	itimerfree(pts, timerid);
708 
709 	return (0);
710 }
711 
712 /*
713  * Set up the given timer. The value in pt->pt_time.it_value is taken
714  * to be an absolute time for CLOCK_REALTIME/CLOCK_MONOTONIC timers and
715  * a relative time for CLOCK_VIRTUAL/CLOCK_PROF timers.
716  *
717  * If the callout had already fired but not yet run, fails with
718  * ERESTART -- caller must restart from the top to look up a timer.
719  */
720 int
721 timer_settime(struct ptimer *pt)
722 {
723 	struct ptimer *ptn, *pptn;
724 	struct ptlist *ptl;
725 
726 	KASSERT(mutex_owned(&timer_lock));
727 
728 	if (!CLOCK_VIRTUAL_P(pt->pt_type)) {
729 		/*
730 		 * Try to stop the callout.  However, if it had already
731 		 * fired, we have to drop the lock to wait for it, so
732 		 * the world may have changed and pt may not be there
733 		 * any more.  In that case, tell the caller to start
734 		 * over from the top.
735 		 */
736 		if (callout_halt(&pt->pt_ch, &timer_lock))
737 			return ERESTART;
738 
739 		/* Now we can touch pt and start it up again.  */
740 		if (timespecisset(&pt->pt_time.it_value)) {
741 			/*
742 			 * Don't need to check tshzto() return value, here.
743 			 * callout_reset() does it for us.
744 			 */
745 			callout_reset(&pt->pt_ch,
746 			    pt->pt_type == CLOCK_MONOTONIC ?
747 			    tshztoup(&pt->pt_time.it_value) :
748 			    tshzto(&pt->pt_time.it_value),
749 			    realtimerexpire, pt);
750 		}
751 	} else {
752 		if (pt->pt_active) {
753 			ptn = LIST_NEXT(pt, pt_list);
754 			LIST_REMOVE(pt, pt_list);
755 			for ( ; ptn; ptn = LIST_NEXT(ptn, pt_list))
756 				timespecadd(&pt->pt_time.it_value,
757 				    &ptn->pt_time.it_value,
758 				    &ptn->pt_time.it_value);
759 		}
760 		if (timespecisset(&pt->pt_time.it_value)) {
761 			if (pt->pt_type == CLOCK_VIRTUAL)
762 				ptl = &pt->pt_proc->p_timers->pts_virtual;
763 			else
764 				ptl = &pt->pt_proc->p_timers->pts_prof;
765 
766 			for (ptn = LIST_FIRST(ptl), pptn = NULL;
767 			     ptn && timespeccmp(&pt->pt_time.it_value,
768 				 &ptn->pt_time.it_value, >);
769 			     pptn = ptn, ptn = LIST_NEXT(ptn, pt_list))
770 				timespecsub(&pt->pt_time.it_value,
771 				    &ptn->pt_time.it_value,
772 				    &pt->pt_time.it_value);
773 
774 			if (pptn)
775 				LIST_INSERT_AFTER(pptn, pt, pt_list);
776 			else
777 				LIST_INSERT_HEAD(ptl, pt, pt_list);
778 
779 			for ( ; ptn ; ptn = LIST_NEXT(ptn, pt_list))
780 				timespecsub(&ptn->pt_time.it_value,
781 				    &pt->pt_time.it_value,
782 				    &ptn->pt_time.it_value);
783 
784 			pt->pt_active = 1;
785 		} else
786 			pt->pt_active = 0;
787 	}
788 
789 	/* Success!  */
790 	return 0;
791 }
792 
793 void
794 timer_gettime(struct ptimer *pt, struct itimerspec *aits)
795 {
796 	struct timespec now;
797 	struct ptimer *ptn;
798 
799 	KASSERT(mutex_owned(&timer_lock));
800 
801 	*aits = pt->pt_time;
802 	if (!CLOCK_VIRTUAL_P(pt->pt_type)) {
803 		/*
804 		 * Convert from absolute to relative time in .it_value
805 		 * part of real time timer.  If time for real time
806 		 * timer has passed return 0, else return difference
807 		 * between current time and time for the timer to go
808 		 * off.
809 		 */
810 		if (timespecisset(&aits->it_value)) {
811 			if (pt->pt_type == CLOCK_REALTIME) {
812 				getnanotime(&now);
813 			} else { /* CLOCK_MONOTONIC */
814 				getnanouptime(&now);
815 			}
816 			if (timespeccmp(&aits->it_value, &now, <))
817 				timespecclear(&aits->it_value);
818 			else
819 				timespecsub(&aits->it_value, &now,
820 				    &aits->it_value);
821 		}
822 	} else if (pt->pt_active) {
823 		if (pt->pt_type == CLOCK_VIRTUAL)
824 			ptn = LIST_FIRST(&pt->pt_proc->p_timers->pts_virtual);
825 		else
826 			ptn = LIST_FIRST(&pt->pt_proc->p_timers->pts_prof);
827 		for ( ; ptn && ptn != pt; ptn = LIST_NEXT(ptn, pt_list))
828 			timespecadd(&aits->it_value,
829 			    &ptn->pt_time.it_value, &aits->it_value);
830 		KASSERT(ptn != NULL); /* pt should be findable on the list */
831 	} else
832 		timespecclear(&aits->it_value);
833 }
834 
835 
836 
837 /* Set and arm a POSIX realtime timer */
838 int
839 sys___timer_settime50(struct lwp *l,
840     const struct sys___timer_settime50_args *uap,
841     register_t *retval)
842 {
843 	/* {
844 		syscallarg(timer_t) timerid;
845 		syscallarg(int) flags;
846 		syscallarg(const struct itimerspec *) value;
847 		syscallarg(struct itimerspec *) ovalue;
848 	} */
849 	int error;
850 	struct itimerspec value, ovalue, *ovp = NULL;
851 
852 	if ((error = copyin(SCARG(uap, value), &value,
853 	    sizeof(struct itimerspec))) != 0)
854 		return (error);
855 
856 	if (SCARG(uap, ovalue))
857 		ovp = &ovalue;
858 
859 	if ((error = dotimer_settime(SCARG(uap, timerid), &value, ovp,
860 	    SCARG(uap, flags), l->l_proc)) != 0)
861 		return error;
862 
863 	if (ovp)
864 		return copyout(&ovalue, SCARG(uap, ovalue),
865 		    sizeof(struct itimerspec));
866 	return 0;
867 }
868 
869 int
870 dotimer_settime(int timerid, struct itimerspec *value,
871     struct itimerspec *ovalue, int flags, struct proc *p)
872 {
873 	struct timespec now;
874 	struct itimerspec val, oval;
875 	struct ptimers *pts;
876 	struct ptimer *pt;
877 	int error;
878 
879 	pts = p->p_timers;
880 
881 	if (pts == NULL || timerid < 2 || timerid >= TIMER_MAX)
882 		return EINVAL;
883 	val = *value;
884 	if ((error = itimespecfix(&val.it_value)) != 0 ||
885 	    (error = itimespecfix(&val.it_interval)) != 0)
886 		return error;
887 
888 	mutex_spin_enter(&timer_lock);
889 restart:
890 	if ((pt = pts->pts_timers[timerid]) == NULL) {
891 		mutex_spin_exit(&timer_lock);
892 		return EINVAL;
893 	}
894 
895 	oval = pt->pt_time;
896 	pt->pt_time = val;
897 
898 	/*
899 	 * If we've been passed a relative time for a realtime timer,
900 	 * convert it to absolute; if an absolute time for a virtual
901 	 * timer, convert it to relative and make sure we don't set it
902 	 * to zero, which would cancel the timer, or let it go
903 	 * negative, which would confuse the comparison tests.
904 	 */
905 	if (timespecisset(&pt->pt_time.it_value)) {
906 		if (!CLOCK_VIRTUAL_P(pt->pt_type)) {
907 			if ((flags & TIMER_ABSTIME) == 0) {
908 				if (pt->pt_type == CLOCK_REALTIME) {
909 					getnanotime(&now);
910 				} else { /* CLOCK_MONOTONIC */
911 					getnanouptime(&now);
912 				}
913 				timespecadd(&pt->pt_time.it_value, &now,
914 				    &pt->pt_time.it_value);
915 			}
916 		} else {
917 			if ((flags & TIMER_ABSTIME) != 0) {
918 				getnanotime(&now);
919 				timespecsub(&pt->pt_time.it_value, &now,
920 				    &pt->pt_time.it_value);
921 				if (!timespecisset(&pt->pt_time.it_value) ||
922 				    pt->pt_time.it_value.tv_sec < 0) {
923 					pt->pt_time.it_value.tv_sec = 0;
924 					pt->pt_time.it_value.tv_nsec = 1;
925 				}
926 			}
927 		}
928 	}
929 
930 	error = timer_settime(pt);
931 	if (error == ERESTART) {
932 		KASSERT(!CLOCK_VIRTUAL_P(pt->pt_type));
933 		goto restart;
934 	}
935 	KASSERT(error == 0);
936 	mutex_spin_exit(&timer_lock);
937 
938 	if (ovalue)
939 		*ovalue = oval;
940 
941 	return (0);
942 }
943 
944 /* Return the time remaining until a POSIX timer fires. */
945 int
946 sys___timer_gettime50(struct lwp *l,
947     const struct sys___timer_gettime50_args *uap, register_t *retval)
948 {
949 	/* {
950 		syscallarg(timer_t) timerid;
951 		syscallarg(struct itimerspec *) value;
952 	} */
953 	struct itimerspec its;
954 	int error;
955 
956 	if ((error = dotimer_gettime(SCARG(uap, timerid), l->l_proc,
957 	    &its)) != 0)
958 		return error;
959 
960 	return copyout(&its, SCARG(uap, value), sizeof(its));
961 }
962 
963 int
964 dotimer_gettime(int timerid, struct proc *p, struct itimerspec *its)
965 {
966 	struct ptimer *pt;
967 	struct ptimers *pts;
968 
969 	pts = p->p_timers;
970 	if (pts == NULL || timerid < 2 || timerid >= TIMER_MAX)
971 		return (EINVAL);
972 	mutex_spin_enter(&timer_lock);
973 	if ((pt = pts->pts_timers[timerid]) == NULL) {
974 		mutex_spin_exit(&timer_lock);
975 		return (EINVAL);
976 	}
977 	timer_gettime(pt, its);
978 	mutex_spin_exit(&timer_lock);
979 
980 	return 0;
981 }
982 
983 /*
984  * Return the count of the number of times a periodic timer expired
985  * while a notification was already pending. The counter is reset when
986  * a timer expires and a notification can be posted.
987  */
988 int
989 sys_timer_getoverrun(struct lwp *l, const struct sys_timer_getoverrun_args *uap,
990     register_t *retval)
991 {
992 	/* {
993 		syscallarg(timer_t) timerid;
994 	} */
995 	struct proc *p = l->l_proc;
996 	struct ptimers *pts;
997 	int timerid;
998 	struct ptimer *pt;
999 
1000 	timerid = SCARG(uap, timerid);
1001 
1002 	pts = p->p_timers;
1003 	if (pts == NULL || timerid < 2 || timerid >= TIMER_MAX)
1004 		return (EINVAL);
1005 	mutex_spin_enter(&timer_lock);
1006 	if ((pt = pts->pts_timers[timerid]) == NULL) {
1007 		mutex_spin_exit(&timer_lock);
1008 		return (EINVAL);
1009 	}
1010 	*retval = pt->pt_poverruns;
1011 	if (*retval >= DELAYTIMER_MAX)
1012 		*retval = DELAYTIMER_MAX;
1013 	mutex_spin_exit(&timer_lock);
1014 
1015 	return (0);
1016 }
1017 
1018 /*
1019  * Real interval timer expired:
1020  * send process whose timer expired an alarm signal.
1021  * If time is not set up to reload, then just return.
1022  * Else compute next time timer should go off which is > current time.
1023  * This is where delay in processing this timeout causes multiple
1024  * SIGALRM calls to be compressed into one.
1025  */
1026 void
1027 realtimerexpire(void *arg)
1028 {
1029 	uint64_t last_val, next_val, interval, now_ns;
1030 	struct timespec now, next;
1031 	struct ptimer *pt;
1032 	int backwards;
1033 
1034 	pt = arg;
1035 
1036 	mutex_spin_enter(&timer_lock);
1037 	itimerfire(pt);
1038 
1039 	if (!timespecisset(&pt->pt_time.it_interval)) {
1040 		timespecclear(&pt->pt_time.it_value);
1041 		mutex_spin_exit(&timer_lock);
1042 		return;
1043 	}
1044 
1045 	if (pt->pt_type == CLOCK_MONOTONIC) {
1046 		getnanouptime(&now);
1047 	} else {
1048 		getnanotime(&now);
1049 	}
1050 	backwards = (timespeccmp(&pt->pt_time.it_value, &now, >));
1051 	timespecadd(&pt->pt_time.it_value, &pt->pt_time.it_interval, &next);
1052 	/* Handle the easy case of non-overflown timers first. */
1053 	if (!backwards && timespeccmp(&next, &now, >)) {
1054 		pt->pt_time.it_value = next;
1055 	} else {
1056 		now_ns = timespec2ns(&now);
1057 		last_val = timespec2ns(&pt->pt_time.it_value);
1058 		interval = timespec2ns(&pt->pt_time.it_interval);
1059 
1060 		next_val = now_ns +
1061 		    (now_ns - last_val + interval - 1) % interval;
1062 
1063 		if (backwards)
1064 			next_val += interval;
1065 		else
1066 			pt->pt_overruns += (now_ns - last_val) / interval;
1067 
1068 		pt->pt_time.it_value.tv_sec = next_val / 1000000000;
1069 		pt->pt_time.it_value.tv_nsec = next_val % 1000000000;
1070 	}
1071 
1072 	/*
1073 	 * Reset the callout, if it's not going away.
1074 	 *
1075 	 * Don't need to check tshzto() return value, here.
1076 	 * callout_reset() does it for us.
1077 	 */
1078 	if (!pt->pt_dying)
1079 		callout_reset(&pt->pt_ch,
1080 		    (pt->pt_type == CLOCK_MONOTONIC
1081 			? tshztoup(&pt->pt_time.it_value)
1082 			: tshzto(&pt->pt_time.it_value)),
1083 		    realtimerexpire, pt);
1084 	mutex_spin_exit(&timer_lock);
1085 }
1086 
1087 /* BSD routine to get the value of an interval timer. */
1088 /* ARGSUSED */
1089 int
1090 sys___getitimer50(struct lwp *l, const struct sys___getitimer50_args *uap,
1091     register_t *retval)
1092 {
1093 	/* {
1094 		syscallarg(int) which;
1095 		syscallarg(struct itimerval *) itv;
1096 	} */
1097 	struct proc *p = l->l_proc;
1098 	struct itimerval aitv;
1099 	int error;
1100 
1101 	memset(&aitv, 0, sizeof(aitv));
1102 	error = dogetitimer(p, SCARG(uap, which), &aitv);
1103 	if (error)
1104 		return error;
1105 	return (copyout(&aitv, SCARG(uap, itv), sizeof(struct itimerval)));
1106 }
1107 
1108 int
1109 dogetitimer(struct proc *p, int which, struct itimerval *itvp)
1110 {
1111 	struct ptimers *pts;
1112 	struct ptimer *pt;
1113 	struct itimerspec its;
1114 
1115 	if ((u_int)which > ITIMER_MONOTONIC)
1116 		return (EINVAL);
1117 
1118 	mutex_spin_enter(&timer_lock);
1119 	pts = p->p_timers;
1120 	if (pts == NULL || (pt = pts->pts_timers[which]) == NULL) {
1121 		timerclear(&itvp->it_value);
1122 		timerclear(&itvp->it_interval);
1123 	} else {
1124 		timer_gettime(pt, &its);
1125 		TIMESPEC_TO_TIMEVAL(&itvp->it_value, &its.it_value);
1126 		TIMESPEC_TO_TIMEVAL(&itvp->it_interval, &its.it_interval);
1127 	}
1128 	mutex_spin_exit(&timer_lock);
1129 
1130 	return 0;
1131 }
1132 
1133 /* BSD routine to set/arm an interval timer. */
1134 /* ARGSUSED */
1135 int
1136 sys___setitimer50(struct lwp *l, const struct sys___setitimer50_args *uap,
1137     register_t *retval)
1138 {
1139 	/* {
1140 		syscallarg(int) which;
1141 		syscallarg(const struct itimerval *) itv;
1142 		syscallarg(struct itimerval *) oitv;
1143 	} */
1144 	struct proc *p = l->l_proc;
1145 	int which = SCARG(uap, which);
1146 	struct sys___getitimer50_args getargs;
1147 	const struct itimerval *itvp;
1148 	struct itimerval aitv;
1149 	int error;
1150 
1151 	if ((u_int)which > ITIMER_MONOTONIC)
1152 		return (EINVAL);
1153 	itvp = SCARG(uap, itv);
1154 	if (itvp &&
1155 	    (error = copyin(itvp, &aitv, sizeof(struct itimerval))) != 0)
1156 		return (error);
1157 	if (SCARG(uap, oitv) != NULL) {
1158 		SCARG(&getargs, which) = which;
1159 		SCARG(&getargs, itv) = SCARG(uap, oitv);
1160 		if ((error = sys___getitimer50(l, &getargs, retval)) != 0)
1161 			return (error);
1162 	}
1163 	if (itvp == 0)
1164 		return (0);
1165 
1166 	return dosetitimer(p, which, &aitv);
1167 }
1168 
1169 int
1170 dosetitimer(struct proc *p, int which, struct itimerval *itvp)
1171 {
1172 	struct timespec now;
1173 	struct ptimers *pts;
1174 	struct ptimer *pt, *spare;
1175 	int error;
1176 
1177 	KASSERT((u_int)which <= CLOCK_MONOTONIC);
1178 	if (itimerfix(&itvp->it_value) || itimerfix(&itvp->it_interval))
1179 		return (EINVAL);
1180 
1181 	/*
1182 	 * Don't bother allocating data structures if the process just
1183 	 * wants to clear the timer.
1184 	 */
1185 	spare = NULL;
1186 	pts = p->p_timers;
1187  retry:
1188 	if (!timerisset(&itvp->it_value) && (pts == NULL ||
1189 	    pts->pts_timers[which] == NULL))
1190 		return (0);
1191 	if (pts == NULL)
1192 		pts = timers_alloc(p);
1193 	mutex_spin_enter(&timer_lock);
1194 restart:
1195 	pt = pts->pts_timers[which];
1196 	if (pt == NULL) {
1197 		if (spare == NULL) {
1198 			mutex_spin_exit(&timer_lock);
1199 			spare = pool_get(&ptimer_pool, PR_WAITOK | PR_ZERO);
1200 			goto retry;
1201 		}
1202 		pt = spare;
1203 		spare = NULL;
1204 		pt->pt_ev.sigev_notify = SIGEV_SIGNAL;
1205 		pt->pt_ev.sigev_value.sival_int = which;
1206 		pt->pt_overruns = 0;
1207 		pt->pt_proc = p;
1208 		pt->pt_type = which;
1209 		pt->pt_entry = which;
1210 		pt->pt_queued = false;
1211 		if (!CLOCK_VIRTUAL_P(which))
1212 			callout_init(&pt->pt_ch, CALLOUT_MPSAFE);
1213 		else
1214 			pt->pt_active = 0;
1215 
1216 		switch (which) {
1217 		case ITIMER_REAL:
1218 		case ITIMER_MONOTONIC:
1219 			pt->pt_ev.sigev_signo = SIGALRM;
1220 			break;
1221 		case ITIMER_VIRTUAL:
1222 			pt->pt_ev.sigev_signo = SIGVTALRM;
1223 			break;
1224 		case ITIMER_PROF:
1225 			pt->pt_ev.sigev_signo = SIGPROF;
1226 			break;
1227 		}
1228 		pts->pts_timers[which] = pt;
1229 	}
1230 
1231 	TIMEVAL_TO_TIMESPEC(&itvp->it_value, &pt->pt_time.it_value);
1232 	TIMEVAL_TO_TIMESPEC(&itvp->it_interval, &pt->pt_time.it_interval);
1233 
1234 	if (timespecisset(&pt->pt_time.it_value)) {
1235 		/* Convert to absolute time */
1236 		/* XXX need to wrap in splclock for timecounters case? */
1237 		switch (which) {
1238 		case ITIMER_REAL:
1239 			getnanotime(&now);
1240 			timespecadd(&pt->pt_time.it_value, &now,
1241 			    &pt->pt_time.it_value);
1242 			break;
1243 		case ITIMER_MONOTONIC:
1244 			getnanouptime(&now);
1245 			timespecadd(&pt->pt_time.it_value, &now,
1246 			    &pt->pt_time.it_value);
1247 			break;
1248 		default:
1249 			break;
1250 		}
1251 	}
1252 	error = timer_settime(pt);
1253 	if (error == ERESTART) {
1254 		KASSERT(!CLOCK_VIRTUAL_P(pt->pt_type));
1255 		goto restart;
1256 	}
1257 	KASSERT(error == 0);
1258 	mutex_spin_exit(&timer_lock);
1259 	if (spare != NULL)
1260 		pool_put(&ptimer_pool, spare);
1261 
1262 	return (0);
1263 }
1264 
1265 /* Utility routines to manage the array of pointers to timers. */
1266 struct ptimers *
1267 timers_alloc(struct proc *p)
1268 {
1269 	struct ptimers *pts;
1270 	int i;
1271 
1272 	pts = pool_get(&ptimers_pool, PR_WAITOK);
1273 	LIST_INIT(&pts->pts_virtual);
1274 	LIST_INIT(&pts->pts_prof);
1275 	for (i = 0; i < TIMER_MAX; i++)
1276 		pts->pts_timers[i] = NULL;
1277 	mutex_spin_enter(&timer_lock);
1278 	if (p->p_timers == NULL) {
1279 		p->p_timers = pts;
1280 		mutex_spin_exit(&timer_lock);
1281 		return pts;
1282 	}
1283 	mutex_spin_exit(&timer_lock);
1284 	pool_put(&ptimers_pool, pts);
1285 	return p->p_timers;
1286 }
1287 
1288 /*
1289  * Clean up the per-process timers. If "which" is set to TIMERS_ALL,
1290  * then clean up all timers and free all the data structures. If
1291  * "which" is set to TIMERS_POSIX, only clean up the timers allocated
1292  * by timer_create(), not the BSD setitimer() timers, and only free the
1293  * structure if none of those remain.
1294  */
1295 void
1296 timers_free(struct proc *p, int which)
1297 {
1298 	struct ptimers *pts;
1299 	struct ptimer *ptn;
1300 	struct timespec ts;
1301 	int i;
1302 
1303 	if (p->p_timers == NULL)
1304 		return;
1305 
1306 	pts = p->p_timers;
1307 	mutex_spin_enter(&timer_lock);
1308 	if (which == TIMERS_ALL) {
1309 		p->p_timers = NULL;
1310 		i = 0;
1311 	} else {
1312 		timespecclear(&ts);
1313 		for (ptn = LIST_FIRST(&pts->pts_virtual);
1314 		     ptn && ptn != pts->pts_timers[ITIMER_VIRTUAL];
1315 		     ptn = LIST_NEXT(ptn, pt_list)) {
1316 			KASSERT(ptn->pt_type == CLOCK_VIRTUAL);
1317 			timespecadd(&ts, &ptn->pt_time.it_value, &ts);
1318 		}
1319 		LIST_FIRST(&pts->pts_virtual) = NULL;
1320 		if (ptn) {
1321 			KASSERT(ptn->pt_type == CLOCK_VIRTUAL);
1322 			timespecadd(&ts, &ptn->pt_time.it_value,
1323 			    &ptn->pt_time.it_value);
1324 			LIST_INSERT_HEAD(&pts->pts_virtual, ptn, pt_list);
1325 		}
1326 		timespecclear(&ts);
1327 		for (ptn = LIST_FIRST(&pts->pts_prof);
1328 		     ptn && ptn != pts->pts_timers[ITIMER_PROF];
1329 		     ptn = LIST_NEXT(ptn, pt_list)) {
1330 			KASSERT(ptn->pt_type == CLOCK_PROF);
1331 			timespecadd(&ts, &ptn->pt_time.it_value, &ts);
1332 		}
1333 		LIST_FIRST(&pts->pts_prof) = NULL;
1334 		if (ptn) {
1335 			KASSERT(ptn->pt_type == CLOCK_PROF);
1336 			timespecadd(&ts, &ptn->pt_time.it_value,
1337 			    &ptn->pt_time.it_value);
1338 			LIST_INSERT_HEAD(&pts->pts_prof, ptn, pt_list);
1339 		}
1340 		i = TIMER_MIN;
1341 	}
1342 	for ( ; i < TIMER_MAX; i++) {
1343 		if (pts->pts_timers[i] != NULL) {
1344 			/* Free the timer and release the lock.  */
1345 			itimerfree(pts, i);
1346 			/* Reacquire the lock for the next one.  */
1347 			mutex_spin_enter(&timer_lock);
1348 		}
1349 	}
1350 	if (pts->pts_timers[0] == NULL && pts->pts_timers[1] == NULL &&
1351 	    pts->pts_timers[2] == NULL && pts->pts_timers[3] == NULL) {
1352 		p->p_timers = NULL;
1353 		mutex_spin_exit(&timer_lock);
1354 		pool_put(&ptimers_pool, pts);
1355 	} else
1356 		mutex_spin_exit(&timer_lock);
1357 }
1358 
1359 static void
1360 itimerfree(struct ptimers *pts, int index)
1361 {
1362 	struct ptimer *pt;
1363 
1364 	KASSERT(mutex_owned(&timer_lock));
1365 
1366 	pt = pts->pts_timers[index];
1367 
1368 	/*
1369 	 * Prevent new references, and notify the callout not to
1370 	 * restart itself.
1371 	 */
1372 	pts->pts_timers[index] = NULL;
1373 	pt->pt_dying = true;
1374 
1375 	/*
1376 	 * For non-virtual timers, stop the callout, or wait for it to
1377 	 * run if it has already fired.  It cannot restart again after
1378 	 * this point: the callout won't restart itself when dying, no
1379 	 * other users holding the lock can restart it, and any other
1380 	 * users waiting for callout_halt concurrently (timer_settime)
1381 	 * will restart from the top.
1382 	 */
1383 	if (!CLOCK_VIRTUAL_P(pt->pt_type))
1384 		callout_halt(&pt->pt_ch, &timer_lock);
1385 
1386 	/* Remove it from the queue to be signalled.  */
1387 	if (pt->pt_queued)
1388 		TAILQ_REMOVE(&timer_queue, pt, pt_chain);
1389 
1390 	/* All done with the global state.  */
1391 	mutex_spin_exit(&timer_lock);
1392 
1393 	/* Destroy the callout, if needed, and free the ptimer.  */
1394 	if (!CLOCK_VIRTUAL_P(pt->pt_type))
1395 		callout_destroy(&pt->pt_ch);
1396 	pool_put(&ptimer_pool, pt);
1397 }
1398 
1399 /*
1400  * Decrement an interval timer by a specified number
1401  * of nanoseconds, which must be less than a second,
1402  * i.e. < 1000000000.  If the timer expires, then reload
1403  * it.  In this case, carry over (nsec - old value) to
1404  * reduce the value reloaded into the timer so that
1405  * the timer does not drift.  This routine assumes
1406  * that it is called in a context where the timers
1407  * on which it is operating cannot change in value.
1408  */
1409 static int
1410 itimerdecr(struct ptimer *pt, int nsec)
1411 {
1412 	struct itimerspec *itp;
1413 	int error __diagused;
1414 
1415 	KASSERT(mutex_owned(&timer_lock));
1416 	KASSERT(CLOCK_VIRTUAL_P(pt->pt_type));
1417 
1418 	itp = &pt->pt_time;
1419 	if (itp->it_value.tv_nsec < nsec) {
1420 		if (itp->it_value.tv_sec == 0) {
1421 			/* expired, and already in next interval */
1422 			nsec -= itp->it_value.tv_nsec;
1423 			goto expire;
1424 		}
1425 		itp->it_value.tv_nsec += 1000000000;
1426 		itp->it_value.tv_sec--;
1427 	}
1428 	itp->it_value.tv_nsec -= nsec;
1429 	nsec = 0;
1430 	if (timespecisset(&itp->it_value))
1431 		return (1);
1432 	/* expired, exactly at end of interval */
1433 expire:
1434 	if (timespecisset(&itp->it_interval)) {
1435 		itp->it_value = itp->it_interval;
1436 		itp->it_value.tv_nsec -= nsec;
1437 		if (itp->it_value.tv_nsec < 0) {
1438 			itp->it_value.tv_nsec += 1000000000;
1439 			itp->it_value.tv_sec--;
1440 		}
1441 		error = timer_settime(pt);
1442 		KASSERT(error == 0); /* virtual, never fails */
1443 	} else
1444 		itp->it_value.tv_nsec = 0;		/* sec is already 0 */
1445 	return (0);
1446 }
1447 
1448 static void
1449 itimerfire(struct ptimer *pt)
1450 {
1451 
1452 	KASSERT(mutex_owned(&timer_lock));
1453 
1454 	/*
1455 	 * XXX Can overrun, but we don't do signal queueing yet, anyway.
1456 	 * XXX Relying on the clock interrupt is stupid.
1457 	 */
1458 	if (pt->pt_ev.sigev_notify != SIGEV_SIGNAL || pt->pt_queued) {
1459 		return;
1460 	}
1461 	TAILQ_INSERT_TAIL(&timer_queue, pt, pt_chain);
1462 	pt->pt_queued = true;
1463 	softint_schedule(timer_sih);
1464 }
1465 
1466 void
1467 timer_tick(lwp_t *l, bool user)
1468 {
1469 	struct ptimers *pts;
1470 	struct ptimer *pt;
1471 	proc_t *p;
1472 
1473 	p = l->l_proc;
1474 	if (p->p_timers == NULL)
1475 		return;
1476 
1477 	mutex_spin_enter(&timer_lock);
1478 	if ((pts = l->l_proc->p_timers) != NULL) {
1479 		/*
1480 		 * Run current process's virtual and profile time, as needed.
1481 		 */
1482 		if (user && (pt = LIST_FIRST(&pts->pts_virtual)) != NULL)
1483 			if (itimerdecr(pt, tick * 1000) == 0)
1484 				itimerfire(pt);
1485 		if ((pt = LIST_FIRST(&pts->pts_prof)) != NULL)
1486 			if (itimerdecr(pt, tick * 1000) == 0)
1487 				itimerfire(pt);
1488 	}
1489 	mutex_spin_exit(&timer_lock);
1490 }
1491 
1492 static void
1493 timer_intr(void *cookie)
1494 {
1495 	ksiginfo_t ksi;
1496 	struct ptimer *pt;
1497 	proc_t *p;
1498 
1499 	mutex_enter(proc_lock);
1500 	mutex_spin_enter(&timer_lock);
1501 	while ((pt = TAILQ_FIRST(&timer_queue)) != NULL) {
1502 		TAILQ_REMOVE(&timer_queue, pt, pt_chain);
1503 		KASSERT(pt->pt_queued);
1504 		pt->pt_queued = false;
1505 
1506 		if (pt->pt_proc->p_timers == NULL) {
1507 			/* Process is dying. */
1508 			continue;
1509 		}
1510 		p = pt->pt_proc;
1511 		if (pt->pt_ev.sigev_notify != SIGEV_SIGNAL) {
1512 			continue;
1513 		}
1514 		if (sigismember(&p->p_sigpend.sp_set, pt->pt_ev.sigev_signo)) {
1515 			pt->pt_overruns++;
1516 			continue;
1517 		}
1518 
1519 		KSI_INIT(&ksi);
1520 		ksi.ksi_signo = pt->pt_ev.sigev_signo;
1521 		ksi.ksi_code = SI_TIMER;
1522 		ksi.ksi_value = pt->pt_ev.sigev_value;
1523 		pt->pt_poverruns = pt->pt_overruns;
1524 		pt->pt_overruns = 0;
1525 		mutex_spin_exit(&timer_lock);
1526 		kpsignal(p, &ksi, NULL);
1527 		mutex_spin_enter(&timer_lock);
1528 	}
1529 	mutex_spin_exit(&timer_lock);
1530 	mutex_exit(proc_lock);
1531 }
1532 
1533 /*
1534  * Check if the time will wrap if set to ts.
1535  *
1536  * ts - timespec describing the new time
1537  * delta - the delta between the current time and ts
1538  */
1539 bool
1540 time_wraps(struct timespec *ts, struct timespec *delta)
1541 {
1542 
1543 	/*
1544 	 * Don't allow the time to be set forward so far it
1545 	 * will wrap and become negative, thus allowing an
1546 	 * attacker to bypass the next check below.  The
1547 	 * cutoff is 1 year before rollover occurs, so even
1548 	 * if the attacker uses adjtime(2) to move the time
1549 	 * past the cutoff, it will take a very long time
1550 	 * to get to the wrap point.
1551 	 */
1552 	if ((ts->tv_sec > LLONG_MAX - 365*24*60*60) ||
1553 	    (delta->tv_sec < 0 || delta->tv_nsec < 0))
1554 		return true;
1555 
1556 	return false;
1557 }
1558