ANSIfication and style cleanups. Non operational.
[dragonfly.git] / sys / kern / kern_time.c
CommitLineData
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1/*
2 * Copyright (c) 1982, 1986, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)kern_time.c 8.1 (Berkeley) 6/10/93
34 * $FreeBSD: src/sys/kern/kern_time.c,v 1.68.2.1 2002/10/01 08:00:41 bde Exp $
88c4d2f6 35 * $DragonFly: src/sys/kern/kern_time.c,v 1.14 2004/01/30 05:42:17 dillon Exp $
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36 */
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/buf.h>
41#include <sys/sysproto.h>
42#include <sys/resourcevar.h>
43#include <sys/signalvar.h>
44#include <sys/kernel.h>
45#include <sys/systm.h>
46#include <sys/sysent.h>
df2244e3 47#include <sys/sysunion.h>
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48#include <sys/proc.h>
49#include <sys/time.h>
50#include <sys/vnode.h>
a94976ad 51#include <sys/sysctl.h>
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52#include <vm/vm.h>
53#include <vm/vm_extern.h>
245e4f17 54#include <sys/msgport2.h>
88c4d2f6 55#include <sys/thread2.h>
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56
57struct timezone tz;
58
59/*
60 * Time of day and interval timer support.
61 *
62 * These routines provide the kernel entry points to get and set
63 * the time-of-day and per-process interval timers. Subroutines
64 * here provide support for adding and subtracting timeval structures
65 * and decrementing interval timers, optionally reloading the interval
66 * timers when they expire.
67 */
68
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69static int nanosleep1 (struct timespec *rqt,
70 struct timespec *rmt);
71static int settime (struct timeval *);
72static void timevalfix (struct timeval *);
73static void no_lease_updatetime (int);
984263bc 74
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75static int sleep_hard_us = 100;
76SYSCTL_INT(_kern, OID_AUTO, sleep_hard_us, CTLFLAG_RW, &sleep_hard_us, 0, "")
a94976ad 77
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78static void
79no_lease_updatetime(deltat)
80 int deltat;
81{
82}
83
402ed7e1 84void (*lease_updatetime) (int) = no_lease_updatetime;
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85
86static int
87settime(tv)
88 struct timeval *tv;
89{
90 struct timeval delta, tv1, tv2;
91 static struct timeval maxtime, laststep;
92 struct timespec ts;
984263bc 93
88c4d2f6 94 crit_enter();
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95 microtime(&tv1);
96 delta = *tv;
97 timevalsub(&delta, &tv1);
98
99 /*
100 * If the system is secure, we do not allow the time to be
101 * set to a value earlier than 1 second less than the highest
102 * time we have yet seen. The worst a miscreant can do in
103 * this circumstance is "freeze" time. He couldn't go
104 * back to the past.
105 *
106 * We similarly do not allow the clock to be stepped more
107 * than one second, nor more than once per second. This allows
108 * a miscreant to make the clock march double-time, but no worse.
109 */
110 if (securelevel > 1) {
111 if (delta.tv_sec < 0 || delta.tv_usec < 0) {
112 /*
113 * Update maxtime to latest time we've seen.
114 */
115 if (tv1.tv_sec > maxtime.tv_sec)
116 maxtime = tv1;
117 tv2 = *tv;
118 timevalsub(&tv2, &maxtime);
119 if (tv2.tv_sec < -1) {
120 tv->tv_sec = maxtime.tv_sec - 1;
121 printf("Time adjustment clamped to -1 second\n");
122 }
123 } else {
124 if (tv1.tv_sec == laststep.tv_sec) {
88c4d2f6 125 crit_exit();
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126 return (EPERM);
127 }
128 if (delta.tv_sec > 1) {
129 tv->tv_sec = tv1.tv_sec + 1;
130 printf("Time adjustment clamped to +1 second\n");
131 }
132 laststep = *tv;
133 }
134 }
135
136 ts.tv_sec = tv->tv_sec;
137 ts.tv_nsec = tv->tv_usec * 1000;
88c4d2f6 138 set_timeofday(&ts);
984263bc 139 lease_updatetime(delta.tv_sec);
88c4d2f6 140 crit_exit();
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141 resettodr();
142 return (0);
143}
144
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145/* ARGSUSED */
146int
41c20dac 147clock_gettime(struct clock_gettime_args *uap)
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148{
149 struct timespec ats;
150
151 if (SCARG(uap, clock_id) != CLOCK_REALTIME)
152 return (EINVAL);
153 nanotime(&ats);
154 return (copyout(&ats, SCARG(uap, tp), sizeof(ats)));
155}
156
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157/* ARGSUSED */
158int
41c20dac 159clock_settime(struct clock_settime_args *uap)
984263bc 160{
dadab5e9 161 struct thread *td = curthread;
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162 struct timeval atv;
163 struct timespec ats;
164 int error;
165
dadab5e9 166 if ((error = suser(td)) != 0)
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167 return (error);
168 if (SCARG(uap, clock_id) != CLOCK_REALTIME)
169 return (EINVAL);
170 if ((error = copyin(SCARG(uap, tp), &ats, sizeof(ats))) != 0)
171 return (error);
172 if (ats.tv_nsec < 0 || ats.tv_nsec >= 1000000000)
173 return (EINVAL);
174 /* XXX Don't convert nsec->usec and back */
175 TIMESPEC_TO_TIMEVAL(&atv, &ats);
176 if ((error = settime(&atv)))
177 return (error);
178 return (0);
179}
180
984263bc 181int
41c20dac 182clock_getres(struct clock_getres_args *uap)
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183{
184 struct timespec ts;
185 int error;
186
187 if (SCARG(uap, clock_id) != CLOCK_REALTIME)
188 return (EINVAL);
189 error = 0;
190 if (SCARG(uap, tp)) {
191 ts.tv_sec = 0;
192 /*
193 * Round up the result of the division cheaply by adding 1.
194 * Rounding up is especially important if rounding down
195 * would give 0. Perfect rounding is unimportant.
196 */
88c4d2f6 197 ts.tv_nsec = 1000000000 / cputimer_freq + 1;
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198 error = copyout(&ts, SCARG(uap, tp), sizeof(ts));
199 }
200 return (error);
201}
202
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203/*
204 * nanosleep1()
205 *
206 * This is a general helper function for nanosleep() (aka sleep() aka
207 * usleep()).
208 *
209 * If there is less then one tick's worth of time left and
210 * we haven't done a yield, or the remaining microseconds is
211 * ridiculously low, do a yield. This avoids having
212 * to deal with systimer overheads when the system is under
213 * heavy loads. If we have done a yield already then use
214 * a systimer and an uninterruptable thread wait.
215 *
216 * If there is more then a tick's worth of time left,
217 * calculate the baseline ticks and use an interruptable
218 * tsleep, then handle the fine-grained delay on the next
219 * loop. This usually results in two sleeps occuring, a long one
220 * and a short one.
221 */
222static void
223ns1_systimer(systimer_t info)
224{
225 lwkt_schedule(info->data);
226}
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227
228static int
41c20dac 229nanosleep1(struct timespec *rqt, struct timespec *rmt)
984263bc 230{
88c4d2f6 231 static int nanowait;
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232 struct timespec ts, ts2, ts3;
233 struct timeval tv;
234 int error;
88c4d2f6 235 int tried_yield;
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236
237 if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)
238 return (EINVAL);
239 if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0))
240 return (0);
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241 nanouptime(&ts);
242 timespecadd(&ts, rqt); /* ts = target timestamp compare */
243 TIMESPEC_TO_TIMEVAL(&tv, rqt); /* tv = sleep interval */
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244 tried_yield = 0;
245
984263bc 246 for (;;) {
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247 int ticks;
248 struct systimer info;
249
250 ticks = tv.tv_usec / tick; /* approximate */
a94976ad 251
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252 if (tv.tv_sec == 0 && ticks == 0) {
253 if (tried_yield || tv.tv_usec < sleep_hard_us) {
254 tried_yield = 0;
a94976ad 255 uio_yield();
a94976ad 256 } else {
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257 crit_enter();
258 systimer_init_oneshot(&info, ns1_systimer,
259 curthread, tv.tv_usec);
260 lwkt_deschedule_self();
261 crit_exit();
262 lwkt_switch();
263 systimer_del(&info); /* make sure it's gone */
a94976ad 264 }
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265 error = iscaught(curproc);
266 } else if (tv.tv_sec == 0) {
267 error = tsleep(&nanowait, PCATCH, "nanslp", ticks);
a94976ad 268 } else {
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269 ticks = tvtohz_low(&tv); /* also handles overflow */
270 error = tsleep(&nanowait, PCATCH, "nanslp", ticks);
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271 }
272 nanouptime(&ts2);
88c4d2f6 273 if (error && error != EWOULDBLOCK) {
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274 if (error == ERESTART)
275 error = EINTR;
276 if (rmt != NULL) {
277 timespecsub(&ts, &ts2);
278 if (ts.tv_sec < 0)
279 timespecclear(&ts);
280 *rmt = ts;
281 }
282 return (error);
283 }
284 if (timespeccmp(&ts2, &ts, >=))
285 return (0);
286 ts3 = ts;
287 timespecsub(&ts3, &ts2);
288 TIMESPEC_TO_TIMEVAL(&tv, &ts3);
289 }
290}
291
245e4f17 292static void nanosleep_done(void *arg);
df2244e3 293static void nanosleep_copyout(union sysunion *sysun);
245e4f17 294
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295/* ARGSUSED */
296int
41c20dac 297nanosleep(struct nanosleep_args *uap)
984263bc 298{
245e4f17 299 int error;
df2244e3 300 struct sysmsg_sleep *smsleep = &uap->sysmsg.sm.sleep;
984263bc 301
df2244e3 302 error = copyin(uap->rqtp, &smsleep->rqt, sizeof(smsleep->rqt));
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303 if (error)
304 return (error);
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305 /*
306 * YYY clean this up to always use the callout, note that an abort
307 * implementation should record the residual in the async case.
308 */
df2244e3 309 if (uap->sysmsg.lmsg.ms_flags & MSGF_ASYNC) {
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310 quad_t ticks;
311
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312 ticks = (quad_t)smsleep->rqt.tv_nsec * hz / 1000000000LL;
313 if (smsleep->rqt.tv_sec)
314 ticks += (quad_t)smsleep->rqt.tv_sec * hz;
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315 if (ticks <= 0) {
316 if (ticks == 0)
317 error = 0;
318 else
319 error = EINVAL;
320 } else {
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321 uap->sysmsg.copyout = nanosleep_copyout;
322 callout_init(&smsleep->timer);
323 callout_reset(&smsleep->timer, ticks, nanosleep_done, uap);
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324 error = EASYNC;
325 }
326 } else {
327 /*
328 * Old synchronous sleep code, copyout the residual if
329 * nanosleep was interrupted.
330 */
df2244e3 331 error = nanosleep1(&smsleep->rqt, &smsleep->rmt);
245e4f17 332 if (error && SCARG(uap, rmtp))
df2244e3 333 error = copyout(&smsleep->rmt, SCARG(uap, rmtp), sizeof(smsleep->rmt));
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334 }
335 return (error);
336}
337
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338/*
339 * Asynch completion for the nanosleep() syscall. This function may be
340 * called from any context and cannot legally access the originating
341 * thread, proc, or its user space.
342 *
343 * YYY change the callout interface API so we can simply assign the replymsg
344 * function to it directly.
345 */
346static void
347nanosleep_done(void *arg)
348{
349 struct nanosleep_args *uap = arg;
350
351 lwkt_replymsg(&uap->sysmsg.lmsg, 0);
352}
353
354/*
355 * Asynch return for the nanosleep() syscall, called in the context of the
356 * originating thread when it pulls the message off the reply port. This
357 * function is responsible for any copyouts to userland. Kernel threads
358 * which do their own internal system calls will not usually call the return
359 * function.
360 */
361static void
df2244e3 362nanosleep_copyout(union sysunion *sysun)
245e4f17 363{
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364 struct nanosleep_args *uap = &sysun->nanosleep;
365 struct sysmsg_sleep *smsleep = &uap->sysmsg.sm.sleep;
245e4f17 366
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367 if (sysun->lmsg.ms_error && uap->rmtp) {
368 sysun->lmsg.ms_error =
369 copyout(&smsleep->rmt, uap->rmtp, sizeof(smsleep->rmt));
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370 }
371}
372
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373/* ARGSUSED */
374int
41c20dac 375gettimeofday(struct gettimeofday_args *uap)
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376{
377 struct timeval atv;
378 int error = 0;
379
380 if (uap->tp) {
381 microtime(&atv);
382 if ((error = copyout((caddr_t)&atv, (caddr_t)uap->tp,
383 sizeof (atv))))
384 return (error);
385 }
386 if (uap->tzp)
387 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp,
388 sizeof (tz));
389 return (error);
390}
391
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392/* ARGSUSED */
393int
41c20dac 394settimeofday(struct settimeofday_args *uap)
984263bc 395{
dadab5e9 396 struct thread *td = curthread;
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397 struct timeval atv;
398 struct timezone atz;
399 int error;
400
dadab5e9 401 if ((error = suser(td)))
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402 return (error);
403 /* Verify all parameters before changing time. */
404 if (uap->tv) {
405 if ((error = copyin((caddr_t)uap->tv, (caddr_t)&atv,
406 sizeof(atv))))
407 return (error);
408 if (atv.tv_usec < 0 || atv.tv_usec >= 1000000)
409 return (EINVAL);
410 }
411 if (uap->tzp &&
412 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz))))
413 return (error);
414 if (uap->tv && (error = settime(&atv)))
415 return (error);
416 if (uap->tzp)
417 tz = atz;
418 return (0);
419}
420
421int tickdelta; /* current clock skew, us. per tick */
422long timedelta; /* unapplied time correction, us. */
423static long bigadj = 1000000; /* use 10x skew above bigadj us. */
424
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425/* ARGSUSED */
426int
41c20dac 427adjtime(struct adjtime_args *uap)
984263bc 428{
dadab5e9 429 struct thread *td = curthread;
984263bc 430 struct timeval atv;
dadab5e9 431 long ndelta, ntickdelta, odelta;
88c4d2f6 432 int error;
984263bc 433
dadab5e9 434 if ((error = suser(td)))
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435 return (error);
436 if ((error =
437 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval))))
438 return (error);
439
440 /*
441 * Compute the total correction and the rate at which to apply it.
442 * Round the adjustment down to a whole multiple of the per-tick
443 * delta, so that after some number of incremental changes in
444 * hardclock(), tickdelta will become zero, lest the correction
445 * overshoot and start taking us away from the desired final time.
446 */
447 ndelta = atv.tv_sec * 1000000 + atv.tv_usec;
448 if (ndelta > bigadj || ndelta < -bigadj)
449 ntickdelta = 10 * tickadj;
450 else
451 ntickdelta = tickadj;
452 if (ndelta % ntickdelta)
453 ndelta = ndelta / ntickdelta * ntickdelta;
454
455 /*
456 * To make hardclock()'s job easier, make the per-tick delta negative
457 * if we want time to run slower; then hardclock can simply compute
458 * tick + tickdelta, and subtract tickdelta from timedelta.
459 */
460 if (ndelta < 0)
461 ntickdelta = -ntickdelta;
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462 /*
463 * XXX not MP safe , but will probably work anyway.
464 */
465 crit_enter();
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466 odelta = timedelta;
467 timedelta = ndelta;
468 tickdelta = ntickdelta;
88c4d2f6 469 crit_exit();
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470
471 if (uap->olddelta) {
472 atv.tv_sec = odelta / 1000000;
473 atv.tv_usec = odelta % 1000000;
474 (void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta,
475 sizeof(struct timeval));
476 }
477 return (0);
478}
479
480/*
481 * Get value of an interval timer. The process virtual and
482 * profiling virtual time timers are kept in the p_stats area, since
483 * they can be swapped out. These are kept internally in the
484 * way they are specified externally: in time until they expire.
485 *
486 * The real time interval timer is kept in the process table slot
487 * for the process, and its value (it_value) is kept as an
488 * absolute time rather than as a delta, so that it is easy to keep
489 * periodic real-time signals from drifting.
490 *
491 * Virtual time timers are processed in the hardclock() routine of
492 * kern_clock.c. The real time timer is processed by a timeout
493 * routine, called from the softclock() routine. Since a callout
494 * may be delayed in real time due to interrupt processing in the system,
495 * it is possible for the real time timeout routine (realitexpire, given below),
496 * to be delayed in real time past when it is supposed to occur. It
497 * does not suffice, therefore, to reload the real timer .it_value from the
498 * real time timers .it_interval. Rather, we compute the next time in
499 * absolute time the timer should go off.
500 */
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501/* ARGSUSED */
502int
41c20dac 503getitimer(struct getitimer_args *uap)
984263bc 504{
41c20dac 505 struct proc *p = curproc;
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506 struct timeval ctv;
507 struct itimerval aitv;
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508
509 if (uap->which > ITIMER_PROF)
510 return (EINVAL);
88c4d2f6 511 crit_enter();
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512 if (uap->which == ITIMER_REAL) {
513 /*
514 * Convert from absolute to relative time in .it_value
515 * part of real time timer. If time for real time timer
516 * has passed return 0, else return difference between
517 * current time and time for the timer to go off.
518 */
519 aitv = p->p_realtimer;
520 if (timevalisset(&aitv.it_value)) {
521 getmicrouptime(&ctv);
522 if (timevalcmp(&aitv.it_value, &ctv, <))
523 timevalclear(&aitv.it_value);
524 else
525 timevalsub(&aitv.it_value, &ctv);
526 }
88c4d2f6 527 } else {
984263bc 528 aitv = p->p_stats->p_timer[uap->which];
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529 }
530 crit_exit();
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531 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv,
532 sizeof (struct itimerval)));
533}
534
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535/* ARGSUSED */
536int
41c20dac 537setitimer(struct setitimer_args *uap)
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538{
539 struct itimerval aitv;
540 struct timeval ctv;
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541 struct itimerval *itvp;
542 struct proc *p = curproc;
88c4d2f6 543 int error;
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544
545 if (uap->which > ITIMER_PROF)
546 return (EINVAL);
547 itvp = uap->itv;
548 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv,
549 sizeof(struct itimerval))))
550 return (error);
551 if ((uap->itv = uap->oitv) &&
41c20dac 552 (error = getitimer((struct getitimer_args *)uap)))
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553 return (error);
554 if (itvp == 0)
555 return (0);
556 if (itimerfix(&aitv.it_value))
557 return (EINVAL);
558 if (!timevalisset(&aitv.it_value))
559 timevalclear(&aitv.it_interval);
560 else if (itimerfix(&aitv.it_interval))
561 return (EINVAL);
88c4d2f6 562 crit_enter();
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563 if (uap->which == ITIMER_REAL) {
564 if (timevalisset(&p->p_realtimer.it_value))
565 untimeout(realitexpire, (caddr_t)p, p->p_ithandle);
566 if (timevalisset(&aitv.it_value))
567 p->p_ithandle = timeout(realitexpire, (caddr_t)p,
a94976ad 568 tvtohz_high(&aitv.it_value));
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569 getmicrouptime(&ctv);
570 timevaladd(&aitv.it_value, &ctv);
571 p->p_realtimer = aitv;
88c4d2f6 572 } else {
984263bc 573 p->p_stats->p_timer[uap->which] = aitv;
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574 }
575 crit_exit();
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576 return (0);
577}
578
579/*
580 * Real interval timer expired:
581 * send process whose timer expired an alarm signal.
582 * If time is not set up to reload, then just return.
583 * Else compute next time timer should go off which is > current time.
584 * This is where delay in processing this timeout causes multiple
585 * SIGALRM calls to be compressed into one.
a94976ad 586 * tvtohz_high() always adds 1 to allow for the time until the next clock
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587 * interrupt being strictly less than 1 clock tick, but we don't want
588 * that here since we want to appear to be in sync with the clock
589 * interrupt even when we're delayed.
590 */
591void
592realitexpire(arg)
593 void *arg;
594{
1fd87d54 595 struct proc *p;
984263bc 596 struct timeval ctv, ntv;
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597
598 p = (struct proc *)arg;
599 psignal(p, SIGALRM);
600 if (!timevalisset(&p->p_realtimer.it_interval)) {
601 timevalclear(&p->p_realtimer.it_value);
602 return;
603 }
604 for (;;) {
88c4d2f6 605 crit_enter();
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606 timevaladd(&p->p_realtimer.it_value,
607 &p->p_realtimer.it_interval);
608 getmicrouptime(&ctv);
609 if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) {
610 ntv = p->p_realtimer.it_value;
611 timevalsub(&ntv, &ctv);
612 p->p_ithandle = timeout(realitexpire, (caddr_t)p,
a94976ad 613 tvtohz_low(&ntv));
88c4d2f6 614 crit_exit();
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615 return;
616 }
88c4d2f6 617 crit_exit();
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618 }
619}
620
621/*
622 * Check that a proposed value to load into the .it_value or
623 * .it_interval part of an interval timer is acceptable, and
624 * fix it to have at least minimal value (i.e. if it is less
625 * than the resolution of the clock, round it up.)
626 */
627int
628itimerfix(tv)
629 struct timeval *tv;
630{
631
632 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 ||
633 tv->tv_usec < 0 || tv->tv_usec >= 1000000)
634 return (EINVAL);
635 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)
636 tv->tv_usec = tick;
637 return (0);
638}
639
640/*
641 * Decrement an interval timer by a specified number
642 * of microseconds, which must be less than a second,
643 * i.e. < 1000000. If the timer expires, then reload
644 * it. In this case, carry over (usec - old value) to
645 * reduce the value reloaded into the timer so that
646 * the timer does not drift. This routine assumes
647 * that it is called in a context where the timers
648 * on which it is operating cannot change in value.
649 */
650int
651itimerdecr(itp, usec)
1fd87d54 652 struct itimerval *itp;
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653 int usec;
654{
655
656 if (itp->it_value.tv_usec < usec) {
657 if (itp->it_value.tv_sec == 0) {
658 /* expired, and already in next interval */
659 usec -= itp->it_value.tv_usec;
660 goto expire;
661 }
662 itp->it_value.tv_usec += 1000000;
663 itp->it_value.tv_sec--;
664 }
665 itp->it_value.tv_usec -= usec;
666 usec = 0;
667 if (timevalisset(&itp->it_value))
668 return (1);
669 /* expired, exactly at end of interval */
670expire:
671 if (timevalisset(&itp->it_interval)) {
672 itp->it_value = itp->it_interval;
673 itp->it_value.tv_usec -= usec;
674 if (itp->it_value.tv_usec < 0) {
675 itp->it_value.tv_usec += 1000000;
676 itp->it_value.tv_sec--;
677 }
678 } else
679 itp->it_value.tv_usec = 0; /* sec is already 0 */
680 return (0);
681}
682
683/*
684 * Add and subtract routines for timevals.
685 * N.B.: subtract routine doesn't deal with
686 * results which are before the beginning,
687 * it just gets very confused in this case.
688 * Caveat emptor.
689 */
690void
691timevaladd(t1, t2)
692 struct timeval *t1, *t2;
693{
694
695 t1->tv_sec += t2->tv_sec;
696 t1->tv_usec += t2->tv_usec;
697 timevalfix(t1);
698}
699
700void
701timevalsub(t1, t2)
702 struct timeval *t1, *t2;
703{
704
705 t1->tv_sec -= t2->tv_sec;
706 t1->tv_usec -= t2->tv_usec;
707 timevalfix(t1);
708}
709
710static void
711timevalfix(t1)
712 struct timeval *t1;
713{
714
715 if (t1->tv_usec < 0) {
716 t1->tv_sec--;
717 t1->tv_usec += 1000000;
718 }
719 if (t1->tv_usec >= 1000000) {
720 t1->tv_sec++;
721 t1->tv_usec -= 1000000;
722 }
723}
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724
725/*
726 * ratecheck(): simple time-based rate-limit checking.
727 */
728int
729ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
730{
731 struct timeval tv, delta;
732 int rv = 0;
733
734 getmicrouptime(&tv); /* NB: 10ms precision */
735 delta = tv;
736 timevalsub(&delta, lasttime);
737
738 /*
739 * check for 0,0 is so that the message will be seen at least once,
740 * even if interval is huge.
741 */
742 if (timevalcmp(&delta, mininterval, >=) ||
743 (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
744 *lasttime = tv;
745 rv = 1;
746 }
747
748 return (rv);
749}
750
751/*
752 * ppsratecheck(): packets (or events) per second limitation.
753 *
754 * Return 0 if the limit is to be enforced (e.g. the caller
755 * should drop a packet because of the rate limitation).
756 *
757 * maxpps of 0 always causes zero to be returned. maxpps of -1
758 * always causes 1 to be returned; this effectively defeats rate
759 * limiting.
760 *
761 * Note that we maintain the struct timeval for compatibility
762 * with other bsd systems. We reuse the storage and just monitor
763 * clock ticks for minimal overhead.
764 */
765int
766ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
767{
768 int now;
769
770 /*
771 * Reset the last time and counter if this is the first call
772 * or more than a second has passed since the last update of
773 * lasttime.
774 */
775 now = ticks;
776 if (lasttime->tv_sec == 0 || (u_int)(now - lasttime->tv_sec) >= hz) {
777 lasttime->tv_sec = now;
778 *curpps = 1;
779 return (maxpps != 0);
780 } else {
781 (*curpps)++; /* NB: ignore potential overflow */
782 return (maxpps < 0 || *curpps < maxpps);
783 }
784}
785