xref: /netbsd-src/sys/kern/kern_time.c (revision 3816d47b2c42fcd6e549e3407f842a5b1a1d23ad)
1 /*	$NetBSD: kern_time.c,v 1.163 2009/12/10 12:39:12 drochner 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 1.163 2009/12/10 12:39:12 drochner 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/sa.h>
79 #include <sys/savar.h>
80 #include <sys/syscallargs.h>
81 #include <sys/cpu.h>
82 
83 #include <uvm/uvm_extern.h>
84 
85 #include "opt_sa.h"
86 
87 static void	timer_intr(void *);
88 static void	itimerfire(struct ptimer *);
89 static void	itimerfree(struct ptimers *, int);
90 
91 kmutex_t	timer_lock;
92 
93 static void	*timer_sih;
94 static TAILQ_HEAD(, ptimer) timer_queue;
95 
96 struct pool ptimer_pool, ptimers_pool;
97 
98 /*
99  * Initialize timekeeping.
100  */
101 void
102 time_init(void)
103 {
104 
105 	pool_init(&ptimer_pool, sizeof(struct ptimer), 0, 0, 0, "ptimerpl",
106 	    &pool_allocator_nointr, IPL_NONE);
107 	pool_init(&ptimers_pool, sizeof(struct ptimers), 0, 0, 0, "ptimerspl",
108 	    &pool_allocator_nointr, IPL_NONE);
109 }
110 
111 void
112 time_init2(void)
113 {
114 
115 	TAILQ_INIT(&timer_queue);
116 	mutex_init(&timer_lock, MUTEX_DEFAULT, IPL_SCHED);
117 	timer_sih = softint_establish(SOFTINT_CLOCK | SOFTINT_MPSAFE,
118 	    timer_intr, NULL);
119 }
120 
121 /* Time of day and interval timer support.
122  *
123  * These routines provide the kernel entry points to get and set
124  * the time-of-day and per-process interval timers.  Subroutines
125  * here provide support for adding and subtracting timeval structures
126  * and decrementing interval timers, optionally reloading the interval
127  * timers when they expire.
128  */
129 
130 /* This function is used by clock_settime and settimeofday */
131 static int
132 settime1(struct proc *p, const struct timespec *ts, bool check_kauth)
133 {
134 	struct timespec delta, now;
135 	int s;
136 
137 	/* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */
138 	s = splclock();
139 	nanotime(&now);
140 	timespecsub(ts, &now, &delta);
141 
142 	if (check_kauth && kauth_authorize_system(kauth_cred_get(),
143 	    KAUTH_SYSTEM_TIME, KAUTH_REQ_SYSTEM_TIME_SYSTEM, __UNCONST(ts),
144 	    &delta, KAUTH_ARG(check_kauth ? false : true)) != 0) {
145 		splx(s);
146 		return (EPERM);
147 	}
148 
149 #ifdef notyet
150 	if ((delta.tv_sec < 86400) && securelevel > 0) { /* XXX elad - notyet */
151 		splx(s);
152 		return (EPERM);
153 	}
154 #endif
155 
156 	tc_setclock(ts);
157 
158 	timespecadd(&boottime, &delta, &boottime);
159 
160 	resettodr();
161 	splx(s);
162 
163 	return (0);
164 }
165 
166 int
167 settime(struct proc *p, struct timespec *ts)
168 {
169 	return (settime1(p, ts, true));
170 }
171 
172 /* ARGSUSED */
173 int
174 sys___clock_gettime50(struct lwp *l,
175     const struct sys___clock_gettime50_args *uap, register_t *retval)
176 {
177 	/* {
178 		syscallarg(clockid_t) clock_id;
179 		syscallarg(struct timespec *) tp;
180 	} */
181 	clockid_t clock_id;
182 	struct timespec ats;
183 
184 	clock_id = SCARG(uap, clock_id);
185 	switch (clock_id) {
186 	case CLOCK_REALTIME:
187 		nanotime(&ats);
188 		break;
189 	case CLOCK_MONOTONIC:
190 		nanouptime(&ats);
191 		break;
192 	default:
193 		return (EINVAL);
194 	}
195 
196 	return copyout(&ats, SCARG(uap, tp), sizeof(ats));
197 }
198 
199 /* ARGSUSED */
200 int
201 sys___clock_settime50(struct lwp *l,
202     const struct sys___clock_settime50_args *uap, register_t *retval)
203 {
204 	/* {
205 		syscallarg(clockid_t) clock_id;
206 		syscallarg(const struct timespec *) tp;
207 	} */
208 	int error;
209 	struct timespec ats;
210 
211 	if ((error = copyin(SCARG(uap, tp), &ats, sizeof(ats))) != 0)
212 		return error;
213 
214 	return clock_settime1(l->l_proc, SCARG(uap, clock_id), &ats, true);
215 }
216 
217 
218 int
219 clock_settime1(struct proc *p, clockid_t clock_id, const struct timespec *tp,
220     bool check_kauth)
221 {
222 	int error;
223 
224 	switch (clock_id) {
225 	case CLOCK_REALTIME:
226 		if ((error = settime1(p, tp, check_kauth)) != 0)
227 			return (error);
228 		break;
229 	case CLOCK_MONOTONIC:
230 		return (EINVAL);	/* read-only clock */
231 	default:
232 		return (EINVAL);
233 	}
234 
235 	return 0;
236 }
237 
238 int
239 sys___clock_getres50(struct lwp *l, const struct sys___clock_getres50_args *uap,
240     register_t *retval)
241 {
242 	/* {
243 		syscallarg(clockid_t) clock_id;
244 		syscallarg(struct timespec *) tp;
245 	} */
246 	clockid_t clock_id;
247 	struct timespec ts;
248 	int error = 0;
249 
250 	clock_id = SCARG(uap, clock_id);
251 	switch (clock_id) {
252 	case CLOCK_REALTIME:
253 	case CLOCK_MONOTONIC:
254 		ts.tv_sec = 0;
255 		if (tc_getfrequency() > 1000000000)
256 			ts.tv_nsec = 1;
257 		else
258 			ts.tv_nsec = 1000000000 / tc_getfrequency();
259 		break;
260 	default:
261 		return (EINVAL);
262 	}
263 
264 	if (SCARG(uap, tp))
265 		error = copyout(&ts, SCARG(uap, tp), sizeof(ts));
266 
267 	return error;
268 }
269 
270 /* ARGSUSED */
271 int
272 sys___nanosleep50(struct lwp *l, const struct sys___nanosleep50_args *uap,
273     register_t *retval)
274 {
275 	/* {
276 		syscallarg(struct timespec *) rqtp;
277 		syscallarg(struct timespec *) rmtp;
278 	} */
279 	struct timespec rmt, rqt;
280 	int error, error1;
281 
282 	error = copyin(SCARG(uap, rqtp), &rqt, sizeof(struct timespec));
283 	if (error)
284 		return (error);
285 
286 	error = nanosleep1(l, &rqt, SCARG(uap, rmtp) ? &rmt : NULL);
287 	if (SCARG(uap, rmtp) == NULL || (error != 0 && error != EINTR))
288 		return error;
289 
290 	error1 = copyout(&rmt, SCARG(uap, rmtp), sizeof(rmt));
291 	return error1 ? error1 : error;
292 }
293 
294 int
295 nanosleep1(struct lwp *l, struct timespec *rqt, struct timespec *rmt)
296 {
297 	struct timespec rmtstart;
298 	int error, timo;
299 
300 	if ((error = itimespecfix(rqt)) != 0)
301 		return error;
302 
303 	timo = tstohz(rqt);
304 	/*
305 	 * Avoid inadvertantly sleeping forever
306 	 */
307 	if (timo == 0)
308 		timo = 1;
309 	getnanouptime(&rmtstart);
310 again:
311 	error = kpause("nanoslp", true, timo, NULL);
312 	if (rmt != NULL || error == 0) {
313 		struct timespec rmtend;
314 		struct timespec t0;
315 		struct timespec *t;
316 
317 		getnanouptime(&rmtend);
318 		t = (rmt != NULL) ? rmt : &t0;
319 		timespecsub(&rmtend, &rmtstart, t);
320 		timespecsub(rqt, t, t);
321 		if (t->tv_sec < 0)
322 			timespecclear(t);
323 		if (error == 0) {
324 			timo = tstohz(t);
325 			if (timo > 0)
326 				goto again;
327 		}
328 	}
329 
330 	if (error == ERESTART)
331 		error = EINTR;
332 	if (error == EWOULDBLOCK)
333 		error = 0;
334 
335 	return error;
336 }
337 
338 /* ARGSUSED */
339 int
340 sys___gettimeofday50(struct lwp *l, const struct sys___gettimeofday50_args *uap,
341     register_t *retval)
342 {
343 	/* {
344 		syscallarg(struct timeval *) tp;
345 		syscallarg(void *) tzp;		really "struct timezone *";
346 	} */
347 	struct timeval atv;
348 	int error = 0;
349 	struct timezone tzfake;
350 
351 	if (SCARG(uap, tp)) {
352 		microtime(&atv);
353 		error = copyout(&atv, SCARG(uap, tp), sizeof(atv));
354 		if (error)
355 			return (error);
356 	}
357 	if (SCARG(uap, tzp)) {
358 		/*
359 		 * NetBSD has no kernel notion of time zone, so we just
360 		 * fake up a timezone struct and return it if demanded.
361 		 */
362 		tzfake.tz_minuteswest = 0;
363 		tzfake.tz_dsttime = 0;
364 		error = copyout(&tzfake, SCARG(uap, tzp), sizeof(tzfake));
365 	}
366 	return (error);
367 }
368 
369 /* ARGSUSED */
370 int
371 sys___settimeofday50(struct lwp *l, const struct sys___settimeofday50_args *uap,
372     register_t *retval)
373 {
374 	/* {
375 		syscallarg(const struct timeval *) tv;
376 		syscallarg(const void *) tzp; really "const struct timezone *";
377 	} */
378 
379 	return settimeofday1(SCARG(uap, tv), true, SCARG(uap, tzp), l, true);
380 }
381 
382 int
383 settimeofday1(const struct timeval *utv, bool userspace,
384     const void *utzp, struct lwp *l, bool check_kauth)
385 {
386 	struct timeval atv;
387 	struct timespec ts;
388 	int error;
389 
390 	/* Verify all parameters before changing time. */
391 
392 	/*
393 	 * NetBSD has no kernel notion of time zone, and only an
394 	 * obsolete program would try to set it, so we log a warning.
395 	 */
396 	if (utzp)
397 		log(LOG_WARNING, "pid %d attempted to set the "
398 		    "(obsolete) kernel time zone\n", l->l_proc->p_pid);
399 
400 	if (utv == NULL)
401 		return 0;
402 
403 	if (userspace) {
404 		if ((error = copyin(utv, &atv, sizeof(atv))) != 0)
405 			return error;
406 		utv = &atv;
407 	}
408 
409 	TIMEVAL_TO_TIMESPEC(utv, &ts);
410 	return settime1(l->l_proc, &ts, check_kauth);
411 }
412 
413 int	time_adjusted;			/* set if an adjustment is made */
414 
415 /* ARGSUSED */
416 int
417 sys___adjtime50(struct lwp *l, const struct sys___adjtime50_args *uap,
418     register_t *retval)
419 {
420 	/* {
421 		syscallarg(const struct timeval *) delta;
422 		syscallarg(struct timeval *) olddelta;
423 	} */
424 	int error = 0;
425 	struct timeval atv, oldatv;
426 
427 	if ((error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_TIME,
428 	    KAUTH_REQ_SYSTEM_TIME_ADJTIME, NULL, NULL, NULL)) != 0)
429 		return error;
430 
431 	if (SCARG(uap, delta)) {
432 		error = copyin(SCARG(uap, delta), &atv,
433 		    sizeof(*SCARG(uap, delta)));
434 		if (error)
435 			return (error);
436 	}
437 	adjtime1(SCARG(uap, delta) ? &atv : NULL,
438 	    SCARG(uap, olddelta) ? &oldatv : NULL, l->l_proc);
439 	if (SCARG(uap, olddelta))
440 		error = copyout(&oldatv, SCARG(uap, olddelta),
441 		    sizeof(*SCARG(uap, olddelta)));
442 	return error;
443 }
444 
445 void
446 adjtime1(const struct timeval *delta, struct timeval *olddelta, struct proc *p)
447 {
448 	extern int64_t time_adjtime;  /* in kern_ntptime.c */
449 
450 	if (olddelta) {
451 		mutex_spin_enter(&timecounter_lock);
452 		olddelta->tv_sec = time_adjtime / 1000000;
453 		olddelta->tv_usec = time_adjtime % 1000000;
454 		if (olddelta->tv_usec < 0) {
455 			olddelta->tv_usec += 1000000;
456 			olddelta->tv_sec--;
457 		}
458 		mutex_spin_exit(&timecounter_lock);
459 	}
460 
461 	if (delta) {
462 		mutex_spin_enter(&timecounter_lock);
463 		time_adjtime = delta->tv_sec * 1000000 + delta->tv_usec;
464 
465 		if (time_adjtime) {
466 			/* We need to save the system time during shutdown */
467 			time_adjusted |= 1;
468 		}
469 		mutex_spin_exit(&timecounter_lock);
470 	}
471 }
472 
473 /*
474  * Interval timer support. Both the BSD getitimer() family and the POSIX
475  * timer_*() family of routines are supported.
476  *
477  * All timers are kept in an array pointed to by p_timers, which is
478  * allocated on demand - many processes don't use timers at all. The
479  * first three elements in this array are reserved for the BSD timers:
480  * element 0 is ITIMER_REAL, element 1 is ITIMER_VIRTUAL, and element
481  * 2 is ITIMER_PROF. The rest may be allocated by the timer_create()
482  * syscall.
483  *
484  * Realtime timers are kept in the ptimer structure as an absolute
485  * time; virtual time timers are kept as a linked list of deltas.
486  * Virtual time timers are processed in the hardclock() routine of
487  * kern_clock.c.  The real time timer is processed by a callout
488  * routine, called from the softclock() routine.  Since a callout may
489  * be delayed in real time due to interrupt processing in the system,
490  * it is possible for the real time timeout routine (realtimeexpire,
491  * given below), to be delayed in real time past when it is supposed
492  * to occur.  It does not suffice, therefore, to reload the real timer
493  * .it_value from the real time timers .it_interval.  Rather, we
494  * compute the next time in absolute time the timer should go off.  */
495 
496 /* Allocate a POSIX realtime timer. */
497 int
498 sys_timer_create(struct lwp *l, const struct sys_timer_create_args *uap,
499     register_t *retval)
500 {
501 	/* {
502 		syscallarg(clockid_t) clock_id;
503 		syscallarg(struct sigevent *) evp;
504 		syscallarg(timer_t *) timerid;
505 	} */
506 
507 	return timer_create1(SCARG(uap, timerid), SCARG(uap, clock_id),
508 	    SCARG(uap, evp), copyin, l);
509 }
510 
511 int
512 timer_create1(timer_t *tid, clockid_t id, struct sigevent *evp,
513     copyin_t fetch_event, struct lwp *l)
514 {
515 	int error;
516 	timer_t timerid;
517 	struct ptimers *pts;
518 	struct ptimer *pt;
519 	struct proc *p;
520 
521 	p = l->l_proc;
522 
523 	if (id < CLOCK_REALTIME || id > CLOCK_PROF)
524 		return (EINVAL);
525 
526 	if ((pts = p->p_timers) == NULL)
527 		pts = timers_alloc(p);
528 
529 	pt = pool_get(&ptimer_pool, PR_WAITOK);
530 	if (evp != NULL) {
531 		if (((error =
532 		    (*fetch_event)(evp, &pt->pt_ev, sizeof(pt->pt_ev))) != 0) ||
533 		    ((pt->pt_ev.sigev_notify < SIGEV_NONE) ||
534 			(pt->pt_ev.sigev_notify > SIGEV_SA)) ||
535 			(pt->pt_ev.sigev_notify == SIGEV_SIGNAL &&
536 			 (pt->pt_ev.sigev_signo <= 0 ||
537 			  pt->pt_ev.sigev_signo >= NSIG))) {
538 			pool_put(&ptimer_pool, pt);
539 			return (error ? error : EINVAL);
540 		}
541 	}
542 
543 	/* Find a free timer slot, skipping those reserved for setitimer(). */
544 	mutex_spin_enter(&timer_lock);
545 	for (timerid = 3; timerid < TIMER_MAX; timerid++)
546 		if (pts->pts_timers[timerid] == NULL)
547 			break;
548 	if (timerid == TIMER_MAX) {
549 		mutex_spin_exit(&timer_lock);
550 		pool_put(&ptimer_pool, pt);
551 		return EAGAIN;
552 	}
553 	if (evp == NULL) {
554 		pt->pt_ev.sigev_notify = SIGEV_SIGNAL;
555 		switch (id) {
556 		case CLOCK_REALTIME:
557 			pt->pt_ev.sigev_signo = SIGALRM;
558 			break;
559 		case CLOCK_VIRTUAL:
560 			pt->pt_ev.sigev_signo = SIGVTALRM;
561 			break;
562 		case CLOCK_PROF:
563 			pt->pt_ev.sigev_signo = SIGPROF;
564 			break;
565 		}
566 		pt->pt_ev.sigev_value.sival_int = timerid;
567 	}
568 	pt->pt_info.ksi_signo = pt->pt_ev.sigev_signo;
569 	pt->pt_info.ksi_errno = 0;
570 	pt->pt_info.ksi_code = 0;
571 	pt->pt_info.ksi_pid = p->p_pid;
572 	pt->pt_info.ksi_uid = kauth_cred_getuid(l->l_cred);
573 	pt->pt_info.ksi_value = pt->pt_ev.sigev_value;
574 	pt->pt_type = id;
575 	pt->pt_proc = p;
576 	pt->pt_overruns = 0;
577 	pt->pt_poverruns = 0;
578 	pt->pt_entry = timerid;
579 	pt->pt_queued = false;
580 	timespecclear(&pt->pt_time.it_value);
581 	if (id == CLOCK_REALTIME)
582 		callout_init(&pt->pt_ch, 0);
583 	else
584 		pt->pt_active = 0;
585 
586 	pts->pts_timers[timerid] = pt;
587 	mutex_spin_exit(&timer_lock);
588 
589 	return copyout(&timerid, tid, sizeof(timerid));
590 }
591 
592 /* Delete a POSIX realtime timer */
593 int
594 sys_timer_delete(struct lwp *l, const struct sys_timer_delete_args *uap,
595     register_t *retval)
596 {
597 	/* {
598 		syscallarg(timer_t) timerid;
599 	} */
600 	struct proc *p = l->l_proc;
601 	timer_t timerid;
602 	struct ptimers *pts;
603 	struct ptimer *pt, *ptn;
604 
605 	timerid = SCARG(uap, timerid);
606 	pts = p->p_timers;
607 
608 	if (pts == NULL || timerid < 2 || timerid >= TIMER_MAX)
609 		return (EINVAL);
610 
611 	mutex_spin_enter(&timer_lock);
612 	if ((pt = pts->pts_timers[timerid]) == NULL) {
613 		mutex_spin_exit(&timer_lock);
614 		return (EINVAL);
615 	}
616 	if (pt->pt_type != CLOCK_REALTIME) {
617 		if (pt->pt_active) {
618 			ptn = LIST_NEXT(pt, pt_list);
619 			LIST_REMOVE(pt, pt_list);
620 			for ( ; ptn; ptn = LIST_NEXT(ptn, pt_list))
621 				timespecadd(&pt->pt_time.it_value,
622 				    &ptn->pt_time.it_value,
623 				    &ptn->pt_time.it_value);
624 			pt->pt_active = 0;
625 		}
626 	}
627 	itimerfree(pts, timerid);
628 
629 	return (0);
630 }
631 
632 /*
633  * Set up the given timer. The value in pt->pt_time.it_value is taken
634  * to be an absolute time for CLOCK_REALTIME timers and a relative
635  * time for virtual timers.
636  * Must be called at splclock().
637  */
638 void
639 timer_settime(struct ptimer *pt)
640 {
641 	struct ptimer *ptn, *pptn;
642 	struct ptlist *ptl;
643 
644 	KASSERT(mutex_owned(&timer_lock));
645 
646 	if (pt->pt_type == CLOCK_REALTIME) {
647 		callout_stop(&pt->pt_ch);
648 		if (timespecisset(&pt->pt_time.it_value)) {
649 			/*
650 			 * Don't need to check tshzto() return value, here.
651 			 * callout_reset() does it for us.
652 			 */
653 			callout_reset(&pt->pt_ch, tshzto(&pt->pt_time.it_value),
654 			    realtimerexpire, pt);
655 		}
656 	} else {
657 		if (pt->pt_active) {
658 			ptn = LIST_NEXT(pt, pt_list);
659 			LIST_REMOVE(pt, pt_list);
660 			for ( ; ptn; ptn = LIST_NEXT(ptn, pt_list))
661 				timespecadd(&pt->pt_time.it_value,
662 				    &ptn->pt_time.it_value,
663 				    &ptn->pt_time.it_value);
664 		}
665 		if (timespecisset(&pt->pt_time.it_value)) {
666 			if (pt->pt_type == CLOCK_VIRTUAL)
667 				ptl = &pt->pt_proc->p_timers->pts_virtual;
668 			else
669 				ptl = &pt->pt_proc->p_timers->pts_prof;
670 
671 			for (ptn = LIST_FIRST(ptl), pptn = NULL;
672 			     ptn && timespeccmp(&pt->pt_time.it_value,
673 				 &ptn->pt_time.it_value, >);
674 			     pptn = ptn, ptn = LIST_NEXT(ptn, pt_list))
675 				timespecsub(&pt->pt_time.it_value,
676 				    &ptn->pt_time.it_value,
677 				    &pt->pt_time.it_value);
678 
679 			if (pptn)
680 				LIST_INSERT_AFTER(pptn, pt, pt_list);
681 			else
682 				LIST_INSERT_HEAD(ptl, pt, pt_list);
683 
684 			for ( ; ptn ; ptn = LIST_NEXT(ptn, pt_list))
685 				timespecsub(&ptn->pt_time.it_value,
686 				    &pt->pt_time.it_value,
687 				    &ptn->pt_time.it_value);
688 
689 			pt->pt_active = 1;
690 		} else
691 			pt->pt_active = 0;
692 	}
693 }
694 
695 void
696 timer_gettime(struct ptimer *pt, struct itimerspec *aits)
697 {
698 	struct timespec now;
699 	struct ptimer *ptn;
700 
701 	KASSERT(mutex_owned(&timer_lock));
702 
703 	*aits = pt->pt_time;
704 	if (pt->pt_type == CLOCK_REALTIME) {
705 		/*
706 		 * Convert from absolute to relative time in .it_value
707 		 * part of real time timer.  If time for real time
708 		 * timer has passed return 0, else return difference
709 		 * between current time and time for the timer to go
710 		 * off.
711 		 */
712 		if (timespecisset(&aits->it_value)) {
713 			getnanotime(&now);
714 			if (timespeccmp(&aits->it_value, &now, <))
715 				timespecclear(&aits->it_value);
716 			else
717 				timespecsub(&aits->it_value, &now,
718 				    &aits->it_value);
719 		}
720 	} else if (pt->pt_active) {
721 		if (pt->pt_type == CLOCK_VIRTUAL)
722 			ptn = LIST_FIRST(&pt->pt_proc->p_timers->pts_virtual);
723 		else
724 			ptn = LIST_FIRST(&pt->pt_proc->p_timers->pts_prof);
725 		for ( ; ptn && ptn != pt; ptn = LIST_NEXT(ptn, pt_list))
726 			timespecadd(&aits->it_value,
727 			    &ptn->pt_time.it_value, &aits->it_value);
728 		KASSERT(ptn != NULL); /* pt should be findable on the list */
729 	} else
730 		timespecclear(&aits->it_value);
731 }
732 
733 
734 
735 /* Set and arm a POSIX realtime timer */
736 int
737 sys___timer_settime50(struct lwp *l,
738     const struct sys___timer_settime50_args *uap,
739     register_t *retval)
740 {
741 	/* {
742 		syscallarg(timer_t) timerid;
743 		syscallarg(int) flags;
744 		syscallarg(const struct itimerspec *) value;
745 		syscallarg(struct itimerspec *) ovalue;
746 	} */
747 	int error;
748 	struct itimerspec value, ovalue, *ovp = NULL;
749 
750 	if ((error = copyin(SCARG(uap, value), &value,
751 	    sizeof(struct itimerspec))) != 0)
752 		return (error);
753 
754 	if (SCARG(uap, ovalue))
755 		ovp = &ovalue;
756 
757 	if ((error = dotimer_settime(SCARG(uap, timerid), &value, ovp,
758 	    SCARG(uap, flags), l->l_proc)) != 0)
759 		return error;
760 
761 	if (ovp)
762 		return copyout(&ovalue, SCARG(uap, ovalue),
763 		    sizeof(struct itimerspec));
764 	return 0;
765 }
766 
767 int
768 dotimer_settime(int timerid, struct itimerspec *value,
769     struct itimerspec *ovalue, int flags, struct proc *p)
770 {
771 	struct timespec now;
772 	struct itimerspec val, oval;
773 	struct ptimers *pts;
774 	struct ptimer *pt;
775 	int error;
776 
777 	pts = p->p_timers;
778 
779 	if (pts == NULL || timerid < 2 || timerid >= TIMER_MAX)
780 		return EINVAL;
781 	val = *value;
782 	if ((error = itimespecfix(&val.it_value)) != 0 ||
783 	    (error = itimespecfix(&val.it_interval)) != 0)
784 		return error;
785 
786 	mutex_spin_enter(&timer_lock);
787 	if ((pt = pts->pts_timers[timerid]) == NULL) {
788 		mutex_spin_exit(&timer_lock);
789 		return EINVAL;
790 	}
791 
792 	oval = pt->pt_time;
793 	pt->pt_time = val;
794 
795 	/*
796 	 * If we've been passed a relative time for a realtime timer,
797 	 * convert it to absolute; if an absolute time for a virtual
798 	 * timer, convert it to relative and make sure we don't set it
799 	 * to zero, which would cancel the timer, or let it go
800 	 * negative, which would confuse the comparison tests.
801 	 */
802 	if (timespecisset(&pt->pt_time.it_value)) {
803 		if (pt->pt_type == CLOCK_REALTIME) {
804 			if ((flags & TIMER_ABSTIME) == 0) {
805 				getnanotime(&now);
806 				timespecadd(&pt->pt_time.it_value, &now,
807 				    &pt->pt_time.it_value);
808 			}
809 		} else {
810 			if ((flags & TIMER_ABSTIME) != 0) {
811 				getnanotime(&now);
812 				timespecsub(&pt->pt_time.it_value, &now,
813 				    &pt->pt_time.it_value);
814 				if (!timespecisset(&pt->pt_time.it_value) ||
815 				    pt->pt_time.it_value.tv_sec < 0) {
816 					pt->pt_time.it_value.tv_sec = 0;
817 					pt->pt_time.it_value.tv_nsec = 1;
818 				}
819 			}
820 		}
821 	}
822 
823 	timer_settime(pt);
824 	mutex_spin_exit(&timer_lock);
825 
826 	if (ovalue)
827 		*ovalue = oval;
828 
829 	return (0);
830 }
831 
832 /* Return the time remaining until a POSIX timer fires. */
833 int
834 sys___timer_gettime50(struct lwp *l,
835     const struct sys___timer_gettime50_args *uap, register_t *retval)
836 {
837 	/* {
838 		syscallarg(timer_t) timerid;
839 		syscallarg(struct itimerspec *) value;
840 	} */
841 	struct itimerspec its;
842 	int error;
843 
844 	if ((error = dotimer_gettime(SCARG(uap, timerid), l->l_proc,
845 	    &its)) != 0)
846 		return error;
847 
848 	return copyout(&its, SCARG(uap, value), sizeof(its));
849 }
850 
851 int
852 dotimer_gettime(int timerid, struct proc *p, struct itimerspec *its)
853 {
854 	struct ptimer *pt;
855 	struct ptimers *pts;
856 
857 	pts = p->p_timers;
858 	if (pts == NULL || timerid < 2 || timerid >= TIMER_MAX)
859 		return (EINVAL);
860 	mutex_spin_enter(&timer_lock);
861 	if ((pt = pts->pts_timers[timerid]) == NULL) {
862 		mutex_spin_exit(&timer_lock);
863 		return (EINVAL);
864 	}
865 	timer_gettime(pt, its);
866 	mutex_spin_exit(&timer_lock);
867 
868 	return 0;
869 }
870 
871 /*
872  * Return the count of the number of times a periodic timer expired
873  * while a notification was already pending. The counter is reset when
874  * a timer expires and a notification can be posted.
875  */
876 int
877 sys_timer_getoverrun(struct lwp *l, const struct sys_timer_getoverrun_args *uap,
878     register_t *retval)
879 {
880 	/* {
881 		syscallarg(timer_t) timerid;
882 	} */
883 	struct proc *p = l->l_proc;
884 	struct ptimers *pts;
885 	int timerid;
886 	struct ptimer *pt;
887 
888 	timerid = SCARG(uap, timerid);
889 
890 	pts = p->p_timers;
891 	if (pts == NULL || timerid < 2 || timerid >= TIMER_MAX)
892 		return (EINVAL);
893 	mutex_spin_enter(&timer_lock);
894 	if ((pt = pts->pts_timers[timerid]) == NULL) {
895 		mutex_spin_exit(&timer_lock);
896 		return (EINVAL);
897 	}
898 	*retval = pt->pt_poverruns;
899 	mutex_spin_exit(&timer_lock);
900 
901 	return (0);
902 }
903 
904 #ifdef KERN_SA
905 /* Glue function that triggers an upcall; called from userret(). */
906 void
907 timerupcall(struct lwp *l)
908 {
909 	struct ptimers *pt = l->l_proc->p_timers;
910 	struct proc *p = l->l_proc;
911 	unsigned int i, fired, done;
912 
913 	KDASSERT(l->l_proc->p_sa);
914 	/* Bail out if we do not own the virtual processor */
915 	if (l->l_savp->savp_lwp != l)
916 		return ;
917 
918 	mutex_enter(p->p_lock);
919 
920 	fired = pt->pts_fired;
921 	done = 0;
922 	while ((i = ffs(fired)) != 0) {
923 		siginfo_t *si;
924 		int mask = 1 << --i;
925 		int f;
926 
927 		f = ~l->l_pflag & LP_SA_NOBLOCK;
928 		l->l_pflag |= LP_SA_NOBLOCK;
929 		si = siginfo_alloc(PR_WAITOK);
930 		si->_info = pt->pts_timers[i]->pt_info.ksi_info;
931 		if (sa_upcall(l, SA_UPCALL_SIGEV | SA_UPCALL_DEFER, NULL, l,
932 		    sizeof(*si), si, siginfo_free) != 0) {
933 			siginfo_free(si);
934 			/* XXX What do we do here?? */
935 		} else
936 			done |= mask;
937 		fired &= ~mask;
938 		l->l_pflag ^= f;
939 	}
940 	pt->pts_fired &= ~done;
941 	if (pt->pts_fired == 0)
942 		l->l_proc->p_timerpend = 0;
943 
944 	mutex_exit(p->p_lock);
945 }
946 #endif /* KERN_SA */
947 
948 /*
949  * Real interval timer expired:
950  * send process whose timer expired an alarm signal.
951  * If time is not set up to reload, then just return.
952  * Else compute next time timer should go off which is > current time.
953  * This is where delay in processing this timeout causes multiple
954  * SIGALRM calls to be compressed into one.
955  */
956 void
957 realtimerexpire(void *arg)
958 {
959 	uint64_t last_val, next_val, interval, now_ms;
960 	struct timespec now, next;
961 	struct ptimer *pt;
962 	int backwards;
963 
964 	pt = arg;
965 
966 	mutex_spin_enter(&timer_lock);
967 	itimerfire(pt);
968 
969 	if (!timespecisset(&pt->pt_time.it_interval)) {
970 		timespecclear(&pt->pt_time.it_value);
971 		mutex_spin_exit(&timer_lock);
972 		return;
973 	}
974 
975 	getnanotime(&now);
976 	backwards = (timespeccmp(&pt->pt_time.it_value, &now, >));
977 	timespecadd(&pt->pt_time.it_value, &pt->pt_time.it_interval, &next);
978 	/* Handle the easy case of non-overflown timers first. */
979 	if (!backwards && timespeccmp(&next, &now, >)) {
980 		pt->pt_time.it_value = next;
981 	} else {
982 		now_ms = timespec2ns(&now);
983 		last_val = timespec2ns(&pt->pt_time.it_value);
984 		interval = timespec2ns(&pt->pt_time.it_interval);
985 
986 		next_val = now_ms +
987 		    (now_ms - last_val + interval - 1) % interval;
988 
989 		if (backwards)
990 			next_val += interval;
991 		else
992 			pt->pt_overruns += (now_ms - last_val) / interval;
993 
994 		pt->pt_time.it_value.tv_sec = next_val / 1000000000;
995 		pt->pt_time.it_value.tv_nsec = next_val % 1000000000;
996 	}
997 
998 	/*
999 	 * Don't need to check tshzto() return value, here.
1000 	 * callout_reset() does it for us.
1001 	 */
1002 	callout_reset(&pt->pt_ch, tshzto(&pt->pt_time.it_value),
1003 	    realtimerexpire, pt);
1004 	mutex_spin_exit(&timer_lock);
1005 }
1006 
1007 /* BSD routine to get the value of an interval timer. */
1008 /* ARGSUSED */
1009 int
1010 sys___getitimer50(struct lwp *l, const struct sys___getitimer50_args *uap,
1011     register_t *retval)
1012 {
1013 	/* {
1014 		syscallarg(int) which;
1015 		syscallarg(struct itimerval *) itv;
1016 	} */
1017 	struct proc *p = l->l_proc;
1018 	struct itimerval aitv;
1019 	int error;
1020 
1021 	error = dogetitimer(p, SCARG(uap, which), &aitv);
1022 	if (error)
1023 		return error;
1024 	return (copyout(&aitv, SCARG(uap, itv), sizeof(struct itimerval)));
1025 }
1026 
1027 int
1028 dogetitimer(struct proc *p, int which, struct itimerval *itvp)
1029 {
1030 	struct ptimers *pts;
1031 	struct ptimer *pt;
1032 	struct itimerspec its;
1033 
1034 	if ((u_int)which > ITIMER_PROF)
1035 		return (EINVAL);
1036 
1037 	mutex_spin_enter(&timer_lock);
1038 	pts = p->p_timers;
1039 	if (pts == NULL || (pt = pts->pts_timers[which]) == NULL) {
1040 		timerclear(&itvp->it_value);
1041 		timerclear(&itvp->it_interval);
1042 	} else {
1043 		timer_gettime(pt, &its);
1044 		TIMESPEC_TO_TIMEVAL(&itvp->it_value, &its.it_value);
1045 		TIMESPEC_TO_TIMEVAL(&itvp->it_interval, &its.it_interval);
1046 	}
1047 	mutex_spin_exit(&timer_lock);
1048 
1049 	return 0;
1050 }
1051 
1052 /* BSD routine to set/arm an interval timer. */
1053 /* ARGSUSED */
1054 int
1055 sys___setitimer50(struct lwp *l, const struct sys___setitimer50_args *uap,
1056     register_t *retval)
1057 {
1058 	/* {
1059 		syscallarg(int) which;
1060 		syscallarg(const struct itimerval *) itv;
1061 		syscallarg(struct itimerval *) oitv;
1062 	} */
1063 	struct proc *p = l->l_proc;
1064 	int which = SCARG(uap, which);
1065 	struct sys___getitimer50_args getargs;
1066 	const struct itimerval *itvp;
1067 	struct itimerval aitv;
1068 	int error;
1069 
1070 	if ((u_int)which > ITIMER_PROF)
1071 		return (EINVAL);
1072 	itvp = SCARG(uap, itv);
1073 	if (itvp &&
1074 	    (error = copyin(itvp, &aitv, sizeof(struct itimerval)) != 0))
1075 		return (error);
1076 	if (SCARG(uap, oitv) != NULL) {
1077 		SCARG(&getargs, which) = which;
1078 		SCARG(&getargs, itv) = SCARG(uap, oitv);
1079 		if ((error = sys___getitimer50(l, &getargs, retval)) != 0)
1080 			return (error);
1081 	}
1082 	if (itvp == 0)
1083 		return (0);
1084 
1085 	return dosetitimer(p, which, &aitv);
1086 }
1087 
1088 int
1089 dosetitimer(struct proc *p, int which, struct itimerval *itvp)
1090 {
1091 	struct timespec now;
1092 	struct ptimers *pts;
1093 	struct ptimer *pt, *spare;
1094 
1095 	if (itimerfix(&itvp->it_value) || itimerfix(&itvp->it_interval))
1096 		return (EINVAL);
1097 
1098 	/*
1099 	 * Don't bother allocating data structures if the process just
1100 	 * wants to clear the timer.
1101 	 */
1102 	spare = NULL;
1103 	pts = p->p_timers;
1104  retry:
1105 	if (!timerisset(&itvp->it_value) && (pts == NULL ||
1106 	    pts->pts_timers[which] == NULL))
1107 		return (0);
1108 	if (pts == NULL)
1109 		pts = timers_alloc(p);
1110 	mutex_spin_enter(&timer_lock);
1111 	pt = pts->pts_timers[which];
1112 	if (pt == NULL) {
1113 		if (spare == NULL) {
1114 			mutex_spin_exit(&timer_lock);
1115 			spare = pool_get(&ptimer_pool, PR_WAITOK);
1116 			goto retry;
1117 		}
1118 		pt = spare;
1119 		spare = NULL;
1120 		pt->pt_ev.sigev_notify = SIGEV_SIGNAL;
1121 		pt->pt_ev.sigev_value.sival_int = which;
1122 		pt->pt_overruns = 0;
1123 		pt->pt_proc = p;
1124 		pt->pt_type = which;
1125 		pt->pt_entry = which;
1126 		pt->pt_queued = false;
1127 		if (pt->pt_type == CLOCK_REALTIME)
1128 			callout_init(&pt->pt_ch, CALLOUT_MPSAFE);
1129 		else
1130 			pt->pt_active = 0;
1131 
1132 		switch (which) {
1133 		case ITIMER_REAL:
1134 			pt->pt_ev.sigev_signo = SIGALRM;
1135 			break;
1136 		case ITIMER_VIRTUAL:
1137 			pt->pt_ev.sigev_signo = SIGVTALRM;
1138 			break;
1139 		case ITIMER_PROF:
1140 			pt->pt_ev.sigev_signo = SIGPROF;
1141 			break;
1142 		}
1143 		pts->pts_timers[which] = pt;
1144 	}
1145 
1146 	TIMEVAL_TO_TIMESPEC(&itvp->it_value, &pt->pt_time.it_value);
1147 	TIMEVAL_TO_TIMESPEC(&itvp->it_interval, &pt->pt_time.it_interval);
1148 
1149 	if ((which == ITIMER_REAL) && timespecisset(&pt->pt_time.it_value)) {
1150 		/* Convert to absolute time */
1151 		/* XXX need to wrap in splclock for timecounters case? */
1152 		getnanotime(&now);
1153 		timespecadd(&pt->pt_time.it_value, &now, &pt->pt_time.it_value);
1154 	}
1155 	timer_settime(pt);
1156 	mutex_spin_exit(&timer_lock);
1157 	if (spare != NULL)
1158 		pool_put(&ptimer_pool, spare);
1159 
1160 	return (0);
1161 }
1162 
1163 /* Utility routines to manage the array of pointers to timers. */
1164 struct ptimers *
1165 timers_alloc(struct proc *p)
1166 {
1167 	struct ptimers *pts;
1168 	int i;
1169 
1170 	pts = pool_get(&ptimers_pool, PR_WAITOK);
1171 	LIST_INIT(&pts->pts_virtual);
1172 	LIST_INIT(&pts->pts_prof);
1173 	for (i = 0; i < TIMER_MAX; i++)
1174 		pts->pts_timers[i] = NULL;
1175 	pts->pts_fired = 0;
1176 	mutex_spin_enter(&timer_lock);
1177 	if (p->p_timers == NULL) {
1178 		p->p_timers = pts;
1179 		mutex_spin_exit(&timer_lock);
1180 		return pts;
1181 	}
1182 	mutex_spin_exit(&timer_lock);
1183 	pool_put(&ptimers_pool, pts);
1184 	return p->p_timers;
1185 }
1186 
1187 /*
1188  * Clean up the per-process timers. If "which" is set to TIMERS_ALL,
1189  * then clean up all timers and free all the data structures. If
1190  * "which" is set to TIMERS_POSIX, only clean up the timers allocated
1191  * by timer_create(), not the BSD setitimer() timers, and only free the
1192  * structure if none of those remain.
1193  */
1194 void
1195 timers_free(struct proc *p, int which)
1196 {
1197 	struct ptimers *pts;
1198 	struct ptimer *ptn;
1199 	struct timespec ts;
1200 	int i;
1201 
1202 	if (p->p_timers == NULL)
1203 		return;
1204 
1205 	pts = p->p_timers;
1206 	mutex_spin_enter(&timer_lock);
1207 	if (which == TIMERS_ALL) {
1208 		p->p_timers = NULL;
1209 		i = 0;
1210 	} else {
1211 		timespecclear(&ts);
1212 		for (ptn = LIST_FIRST(&pts->pts_virtual);
1213 		     ptn && ptn != pts->pts_timers[ITIMER_VIRTUAL];
1214 		     ptn = LIST_NEXT(ptn, pt_list)) {
1215 			KASSERT(ptn->pt_type != CLOCK_REALTIME);
1216 			timespecadd(&ts, &ptn->pt_time.it_value, &ts);
1217 		}
1218 		LIST_FIRST(&pts->pts_virtual) = NULL;
1219 		if (ptn) {
1220 			KASSERT(ptn->pt_type != CLOCK_REALTIME);
1221 			timespecadd(&ts, &ptn->pt_time.it_value,
1222 			    &ptn->pt_time.it_value);
1223 			LIST_INSERT_HEAD(&pts->pts_virtual, ptn, pt_list);
1224 		}
1225 		timespecclear(&ts);
1226 		for (ptn = LIST_FIRST(&pts->pts_prof);
1227 		     ptn && ptn != pts->pts_timers[ITIMER_PROF];
1228 		     ptn = LIST_NEXT(ptn, pt_list)) {
1229 			KASSERT(ptn->pt_type != CLOCK_REALTIME);
1230 			timespecadd(&ts, &ptn->pt_time.it_value, &ts);
1231 		}
1232 		LIST_FIRST(&pts->pts_prof) = NULL;
1233 		if (ptn) {
1234 			KASSERT(ptn->pt_type != CLOCK_REALTIME);
1235 			timespecadd(&ts, &ptn->pt_time.it_value,
1236 			    &ptn->pt_time.it_value);
1237 			LIST_INSERT_HEAD(&pts->pts_prof, ptn, pt_list);
1238 		}
1239 		i = 3;
1240 	}
1241 	for ( ; i < TIMER_MAX; i++) {
1242 		if (pts->pts_timers[i] != NULL) {
1243 			itimerfree(pts, i);
1244 			mutex_spin_enter(&timer_lock);
1245 		}
1246 	}
1247 	if (pts->pts_timers[0] == NULL && pts->pts_timers[1] == NULL &&
1248 	    pts->pts_timers[2] == NULL) {
1249 		p->p_timers = NULL;
1250 		mutex_spin_exit(&timer_lock);
1251 		pool_put(&ptimers_pool, pts);
1252 	} else
1253 		mutex_spin_exit(&timer_lock);
1254 }
1255 
1256 static void
1257 itimerfree(struct ptimers *pts, int index)
1258 {
1259 	struct ptimer *pt;
1260 
1261 	KASSERT(mutex_owned(&timer_lock));
1262 
1263 	pt = pts->pts_timers[index];
1264 	pts->pts_timers[index] = NULL;
1265 	if (pt->pt_type == CLOCK_REALTIME)
1266 		callout_halt(&pt->pt_ch, &timer_lock);
1267 	else if (pt->pt_queued)
1268 		TAILQ_REMOVE(&timer_queue, pt, pt_chain);
1269 	mutex_spin_exit(&timer_lock);
1270 	if (pt->pt_type == CLOCK_REALTIME)
1271 		callout_destroy(&pt->pt_ch);
1272 	pool_put(&ptimer_pool, pt);
1273 }
1274 
1275 /*
1276  * Decrement an interval timer by a specified number
1277  * of nanoseconds, which must be less than a second,
1278  * i.e. < 1000000000.  If the timer expires, then reload
1279  * it.  In this case, carry over (nsec - old value) to
1280  * reduce the value reloaded into the timer so that
1281  * the timer does not drift.  This routine assumes
1282  * that it is called in a context where the timers
1283  * on which it is operating cannot change in value.
1284  */
1285 static int
1286 itimerdecr(struct ptimer *pt, int nsec)
1287 {
1288 	struct itimerspec *itp;
1289 
1290 	KASSERT(mutex_owned(&timer_lock));
1291 
1292 	itp = &pt->pt_time;
1293 	if (itp->it_value.tv_nsec < nsec) {
1294 		if (itp->it_value.tv_sec == 0) {
1295 			/* expired, and already in next interval */
1296 			nsec -= itp->it_value.tv_nsec;
1297 			goto expire;
1298 		}
1299 		itp->it_value.tv_nsec += 1000000000;
1300 		itp->it_value.tv_sec--;
1301 	}
1302 	itp->it_value.tv_nsec -= nsec;
1303 	nsec = 0;
1304 	if (timespecisset(&itp->it_value))
1305 		return (1);
1306 	/* expired, exactly at end of interval */
1307 expire:
1308 	if (timespecisset(&itp->it_interval)) {
1309 		itp->it_value = itp->it_interval;
1310 		itp->it_value.tv_nsec -= nsec;
1311 		if (itp->it_value.tv_nsec < 0) {
1312 			itp->it_value.tv_nsec += 1000000000;
1313 			itp->it_value.tv_sec--;
1314 		}
1315 		timer_settime(pt);
1316 	} else
1317 		itp->it_value.tv_nsec = 0;		/* sec is already 0 */
1318 	return (0);
1319 }
1320 
1321 static void
1322 itimerfire(struct ptimer *pt)
1323 {
1324 
1325 	KASSERT(mutex_owned(&timer_lock));
1326 
1327 	/*
1328 	 * XXX Can overrun, but we don't do signal queueing yet, anyway.
1329 	 * XXX Relying on the clock interrupt is stupid.
1330 	 */
1331 	if ((pt->pt_ev.sigev_notify == SIGEV_SA && pt->pt_proc->p_sa == NULL) ||
1332 	    (pt->pt_ev.sigev_notify != SIGEV_SIGNAL &&
1333 	    pt->pt_ev.sigev_notify != SIGEV_SA) || pt->pt_queued)
1334 		return;
1335 	TAILQ_INSERT_TAIL(&timer_queue, pt, pt_chain);
1336 	pt->pt_queued = true;
1337 	softint_schedule(timer_sih);
1338 }
1339 
1340 void
1341 timer_tick(lwp_t *l, bool user)
1342 {
1343 	struct ptimers *pts;
1344 	struct ptimer *pt;
1345 	proc_t *p;
1346 
1347 	p = l->l_proc;
1348 	if (p->p_timers == NULL)
1349 		return;
1350 
1351 	mutex_spin_enter(&timer_lock);
1352 	if ((pts = l->l_proc->p_timers) != NULL) {
1353 		/*
1354 		 * Run current process's virtual and profile time, as needed.
1355 		 */
1356 		if (user && (pt = LIST_FIRST(&pts->pts_virtual)) != NULL)
1357 			if (itimerdecr(pt, tick * 1000) == 0)
1358 				itimerfire(pt);
1359 		if ((pt = LIST_FIRST(&pts->pts_prof)) != NULL)
1360 			if (itimerdecr(pt, tick * 1000) == 0)
1361 				itimerfire(pt);
1362 	}
1363 	mutex_spin_exit(&timer_lock);
1364 }
1365 
1366 #ifdef KERN_SA
1367 /*
1368  * timer_sa_intr:
1369  *
1370  *	SIGEV_SA handling for timer_intr(). We are called (and return)
1371  * with the timer lock held. We know that the process had SA enabled
1372  * when this timer was enqueued. As timer_intr() is a soft interrupt
1373  * handler, SA should still be enabled by the time we get here.
1374  */
1375 static void
1376 timer_sa_intr(struct ptimer *pt, proc_t *p)
1377 {
1378 	unsigned int		i;
1379 	struct sadata		*sa;
1380 	struct sadata_vp	*vp;
1381 
1382 	/* Cause the process to generate an upcall when it returns. */
1383 	if (!p->p_timerpend) {
1384 		/*
1385 		 * XXX stop signals can be processed inside tsleep,
1386 		 * which can be inside sa_yield's inner loop, which
1387 		 * makes testing for sa_idle alone insuffucent to
1388 		 * determine if we really should call setrunnable.
1389 		 */
1390 		pt->pt_poverruns = pt->pt_overruns;
1391 		pt->pt_overruns = 0;
1392 		i = 1 << pt->pt_entry;
1393 		p->p_timers->pts_fired = i;
1394 		p->p_timerpend = 1;
1395 
1396 		sa = p->p_sa;
1397 		mutex_enter(&sa->sa_mutex);
1398 		SLIST_FOREACH(vp, &sa->sa_vps, savp_next) {
1399 			struct lwp *vp_lwp = vp->savp_lwp;
1400 			lwp_lock(vp_lwp);
1401 			lwp_need_userret(vp_lwp);
1402 			if (vp_lwp->l_flag & LW_SA_IDLE) {
1403 				vp_lwp->l_flag &= ~LW_SA_IDLE;
1404 				lwp_unsleep(vp_lwp, true);
1405 				break;
1406 			}
1407 			lwp_unlock(vp_lwp);
1408 		}
1409 		mutex_exit(&sa->sa_mutex);
1410 	} else {
1411 		i = 1 << pt->pt_entry;
1412 		if ((p->p_timers->pts_fired & i) == 0) {
1413 			pt->pt_poverruns = pt->pt_overruns;
1414 			pt->pt_overruns = 0;
1415 			p->p_timers->pts_fired |= i;
1416 		} else
1417 			pt->pt_overruns++;
1418 	}
1419 }
1420 #endif /* KERN_SA */
1421 
1422 static void
1423 timer_intr(void *cookie)
1424 {
1425 	ksiginfo_t ksi;
1426 	struct ptimer *pt;
1427 	proc_t *p;
1428 
1429 	mutex_enter(proc_lock);
1430 	mutex_spin_enter(&timer_lock);
1431 	while ((pt = TAILQ_FIRST(&timer_queue)) != NULL) {
1432 		TAILQ_REMOVE(&timer_queue, pt, pt_chain);
1433 		KASSERT(pt->pt_queued);
1434 		pt->pt_queued = false;
1435 
1436 		if (pt->pt_proc->p_timers == NULL) {
1437 			/* Process is dying. */
1438 			continue;
1439 		}
1440 		p = pt->pt_proc;
1441 #ifdef KERN_SA
1442 		if (pt->pt_ev.sigev_notify == SIGEV_SA) {
1443 			timer_sa_intr(pt, p);
1444 			continue;
1445 		}
1446 #endif /* KERN_SA */
1447 		if (pt->pt_ev.sigev_notify != SIGEV_SIGNAL)
1448 			continue;
1449 		if (sigismember(&p->p_sigpend.sp_set, pt->pt_ev.sigev_signo)) {
1450 			pt->pt_overruns++;
1451 			continue;
1452 		}
1453 
1454 		KSI_INIT(&ksi);
1455 		ksi.ksi_signo = pt->pt_ev.sigev_signo;
1456 		ksi.ksi_code = SI_TIMER;
1457 		ksi.ksi_value = pt->pt_ev.sigev_value;
1458 		pt->pt_poverruns = pt->pt_overruns;
1459 		pt->pt_overruns = 0;
1460 		mutex_spin_exit(&timer_lock);
1461 		kpsignal(p, &ksi, NULL);
1462 		mutex_spin_enter(&timer_lock);
1463 	}
1464 	mutex_spin_exit(&timer_lock);
1465 	mutex_exit(proc_lock);
1466 }
1467 
1468 /*
1469  * Check if the time will wrap if set to ts.
1470  *
1471  * ts - timespec describing the new time
1472  * delta - the delta between the current time and ts
1473  */
1474 bool
1475 time_wraps(struct timespec *ts, struct timespec *delta)
1476 {
1477 
1478 	/*
1479 	 * Don't allow the time to be set forward so far it
1480 	 * will wrap and become negative, thus allowing an
1481 	 * attacker to bypass the next check below.  The
1482 	 * cutoff is 1 year before rollover occurs, so even
1483 	 * if the attacker uses adjtime(2) to move the time
1484 	 * past the cutoff, it will take a very long time
1485 	 * to get to the wrap point.
1486 	 */
1487 	if ((ts->tv_sec > LLONG_MAX - 365*24*60*60) ||
1488 	    (delta->tv_sec < 0 || delta->tv_nsec < 0))
1489 		return true;
1490 
1491 	return false;
1492 }
1493