bsd/kern/kern_time.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  26 /*
  27  * Copyright (c) 1982, 1986, 1989, 1993
  28  *      The Regents of the University of California.  All rights reserved.
  29  *
  30  * Redistribution and use in source and binary forms, with or without
  31  * modification, are permitted provided that the following conditions
  32  * are met:
  33  * 1. Redistributions of source code must retain the above copyright
  34  *    notice, this list of conditions and the following disclaimer.
  35  * 2. Redistributions in binary form must reproduce the above copyright
  36  *    notice, this list of conditions and the following disclaimer in the
  37  *    documentation and/or other materials provided with the distribution.
  38  * 3. All advertising materials mentioning features or use of this software
  39  *    must display the following acknowledgement:
  40  *      This product includes software developed by the University of
  41  *      California, Berkeley and its contributors.
  42  * 4. Neither the name of the University nor the names of its contributors
  43  *    may be used to endorse or promote products derived from this software
  44  *    without specific prior written permission.
  45  *
  46  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  47  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  48  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  49  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  50  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  51  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  52  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  53  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  54  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  55  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  56  * SUCH DAMAGE.
  57  *
  58  *      @(#)kern_time.c 8.4 (Berkeley) 5/26/95
  59  */
  60
  61 #include <sys/param.h>
  62 #include <sys/resourcevar.h>
  63 #include <sys/kernel.h>
  64 #include <sys/systm.h>
  65 #include <sys/proc.h>
  66 #include <sys/vnode.h>
  67
  68 #include <sys/mount.h>
  69
  70 #include <kern/clock.h>
  71
  72 #define HZ      100     /* XXX */
  73
  74 volatile struct timeval         time;
  75 /* simple lock used to access timezone, tz structure */
  76 decl_simple_lock_data(, tz_slock);
  77 /*
  78  * Time of day and interval timer support.
  79  *
  80  * These routines provide the kernel entry points to get and set
  81  * the time-of-day and per-process interval timers.  Subroutines
  82  * here provide support for adding and subtracting timeval structures
  83  * and decrementing interval timers, optionally reloading the interval
  84  * timers when they expire.
  85  */
  86 struct gettimeofday_args{
  87         struct timeval *tp;
  88         struct timezone *tzp;
  89 };
  90 /* ARGSUSED */
  91 int
  92 gettimeofday(p, uap, retval)
  93         struct proc *p;
  94         register struct gettimeofday_args *uap;
  95         register_t *retval;
  96 {
  97         struct timeval atv;
  98         int error = 0;
  99         extern simple_lock_data_t tz_slock;
 100         struct timezone ltz; /* local copy */
 101
 102 /*  NOTE THIS implementation is for non ppc architectures only */
 103
 104         if (uap->tp) {
 105                 microtime(&atv);
 106                 if (error = copyout((caddr_t)&atv, (caddr_t)uap->tp,
 107                         sizeof (atv)))
 108                         return(error);
 109         }
 110
 111         if (uap->tzp) {
 112                 usimple_lock(&tz_slock);
 113                 ltz = tz;
 114                 usimple_unlock(&tz_slock);
 115                 error = copyout((caddr_t)&ltz, (caddr_t)uap->tzp,
 116                     sizeof (tz));
 117         }
 118
 119         return(error);
 120 }
 121
 122 struct settimeofday_args {
 123         struct timeval *tv;
 124         struct timezone *tzp;
 125 };
 126 /* ARGSUSED */
 127 int
 128 settimeofday(p, uap, retval)
 129         struct proc *p;
 130         struct settimeofday_args  *uap;
 131         register_t *retval;
 132 {
 133         struct timeval atv;
 134         struct timezone atz;
 135         int error, s;
 136         extern simple_lock_data_t tz_slock;
 137
 138         if (error = suser(p->p_ucred, &p->p_acflag))
 139                 return (error);
 140         /* Verify all parameters before changing time. */
 141         if (uap->tv && (error = copyin((caddr_t)uap->tv,
 142             (caddr_t)&atv, sizeof(atv))))
 143                 return (error);
 144         if (uap->tzp && (error = copyin((caddr_t)uap->tzp,
 145             (caddr_t)&atz, sizeof(atz))))
 146                 return (error);
 147         if (uap->tv)
 148                 setthetime(&atv);
 149         if (uap->tzp) {
 150                 usimple_lock(&tz_slock);
 151                 tz = atz;
 152                 usimple_unlock(&tz_slock);
 153         }
 154         return (0);
 155 }
 156
 157 setthetime(tv)
 158         struct timeval *tv;
 159 {
 160         long delta = tv->tv_sec - time.tv_sec;
 161         mach_timespec_t now;
 162
 163         now.tv_sec = tv->tv_sec;
 164         now.tv_nsec = tv->tv_usec * NSEC_PER_USEC;
 165
 166         clock_set_calendar_value(now);
 167         boottime.tv_sec += delta;
 168 #if NFSCLIENT || NFSSERVER
 169         lease_updatetime(delta);
 170 #endif
 171 }
 172
 173 #define tickadj         (40 * NSEC_PER_USEC)    /* "standard" skew, ns / 10 ms */
 174 #define bigadj          (1 * NSEC_PER_SEC)              /* use 10x skew above bigadj ns */
 175
 176 struct adjtime_args {
 177         struct timeval *delta;
 178         struct timeval *olddelta;
 179 };
 180 /* ARGSUSED */
 181 int
 182 adjtime(p, uap, retval)
 183         struct proc *p;
 184         register struct adjtime_args *uap;
 185         register_t *retval;
 186 {
 187         struct timeval atv;
 188         int64_t total;
 189         uint32_t delta;
 190         int error;
 191
 192         if (error = suser(p->p_ucred, &p->p_acflag))
 193                 return (error);
 194         if (error = copyin((caddr_t)uap->delta,
 195                                                         (caddr_t)&atv, sizeof (struct timeval)))
 196                 return (error);
 197
 198     /*
 199      * Compute the total correction and the rate at which to apply it.
 200      */
 201         total = (int64_t)atv.tv_sec * NSEC_PER_SEC + atv.tv_usec * NSEC_PER_USEC;
 202         if (total > bigadj || total < -bigadj)
 203                 delta = 10 * tickadj;
 204         else
 205                 delta = tickadj;
 206
 207         total = clock_set_calendar_adjtime(total, delta);
 208
 209         if (uap->olddelta) {
 210                 atv.tv_sec = total / NSEC_PER_SEC;
 211                 atv.tv_usec = (total / NSEC_PER_USEC) % USEC_PER_SEC;
 212                 (void) copyout((caddr_t)&atv,
 213                                                         (caddr_t)uap->olddelta, sizeof (struct timeval));
 214         }
 215
 216         return (0);
 217 }
 218
 219 /*
 220  * Initialze the time of day register.
 221  * Trust the RTC except for the case where it is set before
 222  * the UNIX epoch. In that case use the the UNIX epoch.
 223  * The argument passed in is ignored.
 224  */
 225 void
 226 inittodr(base)
 227         time_t base;
 228 {
 229         /*
 230          * Assertion:
 231          * The calendar has already been
 232          * set up from the battery clock.
 233          *
 234          * The value returned by microtime()
 235          * is gotten from the calendar.
 236          */
 237         microtime(&time);
 238
 239         /*
 240          * This variable still exists to keep
 241          * 'w' happy.  It should only be considered
 242          * an approximation.
 243          */
 244         boottime.tv_sec = time.tv_sec;
 245         boottime.tv_usec = 0;
 246
 247         /*
 248          * If the RTC does not have acceptable value, i.e. time before
 249          * the UNIX epoch, set it to the UNIX epoch
 250          */
 251         if (time.tv_sec < 0) {
 252                 printf ("WARNING: preposterous time in Real Time Clock");
 253                 time.tv_sec = 0;        /* the UNIX epoch */
 254                 time.tv_usec = 0;
 255                 setthetime(&time);
 256                 boottime = time;
 257                 printf(" -- CHECK AND RESET THE DATE!\n");
 258         }
 259
 260         return;
 261 }
 262
 263 void    timevaladd(
 264                         struct timeval  *t1,
 265                         struct timeval  *t2);
 266 void    timevalsub(
 267                         struct timeval  *t1,
 268                         struct timeval  *t2);
 269 void    timevalfix(
 270                         struct timeval  *t1);
 271
 272 uint64_t
 273                 tvtoabstime(
 274                         struct timeval  *tvp);
 275
 276 /*
 277  * Get value of an interval timer.  The process virtual and
 278  * profiling virtual time timers are kept internally in the
 279  * way they are specified externally: in time until they expire.
 280  *
 281  * The real time interval timer expiration time (p_rtime)
 282  * is kept as an absolute time rather than as a delta, so that
 283  * it is easy to keep periodic real-time signals from drifting.
 284  *
 285  * Virtual time timers are processed in the hardclock() routine of
 286  * kern_clock.c.  The real time timer is processed by a callout
 287  * routine.  Since a callout may be delayed in real time due to
 288  * other processing in the system, it is possible for the real
 289  * time callout routine (realitexpire, given below), to be delayed
 290  * in real time past when it is supposed to occur.  It does not
 291  * suffice, therefore, to reload the real time .it_value from the
 292  * real time .it_interval.  Rather, we compute the next time in
 293  * absolute time when the timer should go off.
 294  */
 295
 296 struct getitimer_args {
 297         u_int   which;
 298         struct itimerval *itv;
 299 };
 300 /* ARGSUSED */
 301 int
 302 getitimer(p, uap, retval)
 303         struct proc *p;
 304         register struct getitimer_args *uap;
 305         register_t *retval;
 306 {
 307         struct itimerval aitv;
 308
 309         if (uap->which > ITIMER_PROF)
 310                 return(EINVAL);
 311         if (uap->which == ITIMER_REAL) {
 312                 /*
 313                  * If time for real time timer has passed return 0,
 314                  * else return difference between current time and
 315                  * time for the timer to go off.
 316                  */
 317                 aitv = p->p_realtimer;
 318                 if (timerisset(&p->p_rtime)) {
 319                         struct timeval          now;
 320
 321                         microuptime(&now);
 322                         if (timercmp(&p->p_rtime, &now, <))
 323                                 timerclear(&aitv.it_value);
 324                         else {
 325                                 aitv.it_value = p->p_rtime;
 326                                 timevalsub(&aitv.it_value, &now);
 327                         }
 328                 }
 329                 else
 330                         timerclear(&aitv.it_value);
 331         }
 332         else
 333                 aitv = p->p_stats->p_timer[uap->which];
 334
 335         return (copyout((caddr_t)&aitv,
 336                                                 (caddr_t)uap->itv, sizeof (struct itimerval)));
 337 }
 338
 339 struct setitimer_args {
 340         u_int   which;
 341         struct  itimerval *itv;
 342         struct  itimerval *oitv;
 343 };
 344 /* ARGSUSED */
 345 int
 346 setitimer(p, uap, retval)
 347         struct proc *p;
 348         register struct setitimer_args *uap;
 349         register_t *retval;
 350 {
 351         struct itimerval aitv;
 352         register struct itimerval *itvp;
 353         int error;
 354
 355         if (uap->which > ITIMER_PROF)
 356                 return (EINVAL);
 357         if ((itvp = uap->itv) &&
 358                 (error = copyin((caddr_t)itvp,
 359                                                         (caddr_t)&aitv, sizeof (struct itimerval))))
 360                 return (error);
 361         if ((uap->itv = uap->oitv) && (error = getitimer(p, uap, retval)))
 362                 return (error);
 363         if (itvp == 0)
 364                 return (0);
 365         if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval))
 366                 return (EINVAL);
 367         if (uap->which == ITIMER_REAL) {
 368                 thread_call_func_cancel(realitexpire, (void *)p->p_pid, FALSE);
 369                 if (timerisset(&aitv.it_value)) {
 370                         microuptime(&p->p_rtime);
 371                         timevaladd(&p->p_rtime, &aitv.it_value);
 372                         thread_call_func_delayed(
 373                                                                 realitexpire, (void *)p->p_pid,
 374                                                                                 tvtoabstime(&p->p_rtime));
 375                 }
 376                 else
 377                         timerclear(&p->p_rtime);
 378
 379                 p->p_realtimer = aitv;
 380         }
 381         else
 382                 p->p_stats->p_timer[uap->which] = aitv;
 383
 384         return (0);
 385 }
 386
 387 /*
 388  * Real interval timer expired:
 389  * send process whose timer expired an alarm signal.
 390  * If time is not set up to reload, then just return.
 391  * Else compute next time timer should go off which is > current time.
 392  * This is where delay in processing this timeout causes multiple
 393  * SIGALRM calls to be compressed into one.
 394  */
 395 void
 396 realitexpire(
 397         void            *pid)
 398 {
 399         register struct proc *p;
 400         struct timeval  now;
 401         boolean_t               funnel_state = thread_funnel_set(kernel_flock, TRUE);
 402
 403         p = pfind((pid_t)pid);
 404         if (p == NULL) {
 405                 (void) thread_funnel_set(kernel_flock, FALSE);
 406                 return;
 407         }
 408
 409         if (!timerisset(&p->p_realtimer.it_interval)) {
 410                 timerclear(&p->p_rtime);
 411                 psignal(p, SIGALRM);
 412
 413                 (void) thread_funnel_set(kernel_flock, FALSE);
 414                 return;
 415         }
 416
 417         microuptime(&now);
 418         timevaladd(&p->p_rtime, &p->p_realtimer.it_interval);
 419         if (timercmp(&p->p_rtime, &now, <=)) {
 420                 if ((p->p_rtime.tv_sec + 2) >= now.tv_sec) {
 421                         for (;;) {
 422                                 timevaladd(&p->p_rtime, &p->p_realtimer.it_interval);
 423                                 if (timercmp(&p->p_rtime, &now, >))
 424                                         break;
 425                         }
 426                 }
 427                 else {
 428                         p->p_rtime = p->p_realtimer.it_interval;
 429                         timevaladd(&p->p_rtime, &now);
 430                 }
 431         }
 432
 433         thread_call_func_delayed(realitexpire, pid, tvtoabstime(&p->p_rtime));
 434
 435         psignal(p, SIGALRM);
 436
 437         (void) thread_funnel_set(kernel_flock, FALSE);
 438 }
 439
 440 /*
 441  * Check that a proposed value to load into the .it_value or
 442  * .it_interval part of an interval timer is acceptable, and
 443  * fix it to have at least minimal value (i.e. if it is less
 444  * than the resolution of the clock, round it up.)
 445  */
 446 int
 447 itimerfix(tv)
 448         struct timeval *tv;
 449 {
 450
 451         if (tv->tv_sec < 0 || tv->tv_sec > 100000000 ||
 452             tv->tv_usec < 0 || tv->tv_usec >= 1000000)
 453                 return (EINVAL);
 454         if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)
 455                 tv->tv_usec = tick;
 456         return (0);
 457 }
 458
 459 /*
 460  * Decrement an interval timer by a specified number
 461  * of microseconds, which must be less than a second,
 462  * i.e. < 1000000.  If the timer expires, then reload
 463  * it.  In this case, carry over (usec - old value) to
 464  * reducint the value reloaded into the timer so that
 465  * the timer does not drift.  This routine assumes
 466  * that it is called in a context where the timers
 467  * on which it is operating cannot change in value.
 468  */
 469 int
 470 itimerdecr(itp, usec)
 471         register struct itimerval *itp;
 472         int usec;
 473 {
 474
 475         if (itp->it_value.tv_usec < usec) {
 476                 if (itp->it_value.tv_sec == 0) {
 477                         /* expired, and already in next interval */
 478                         usec -= itp->it_value.tv_usec;
 479                         goto expire;
 480                 }
 481                 itp->it_value.tv_usec += 1000000;
 482                 itp->it_value.tv_sec--;
 483         }
 484         itp->it_value.tv_usec -= usec;
 485         usec = 0;
 486         if (timerisset(&itp->it_value))
 487                 return (1);
 488         /* expired, exactly at end of interval */
 489 expire:
 490         if (timerisset(&itp->it_interval)) {
 491                 itp->it_value = itp->it_interval;
 492                 itp->it_value.tv_usec -= usec;
 493                 if (itp->it_value.tv_usec < 0) {
 494                         itp->it_value.tv_usec += 1000000;
 495                         itp->it_value.tv_sec--;
 496                 }
 497         } else
 498                 itp->it_value.tv_usec = 0;              /* sec is already 0 */
 499         return (0);
 500 }
 501
 502 /*
 503  * Add and subtract routines for timevals.
 504  * N.B.: subtract routine doesn't deal with
 505  * results which are before the beginning,
 506  * it just gets very confused in this case.
 507  * Caveat emptor.
 508  */
 509 void
 510 timevaladd(
 511         struct timeval *t1,
 512         struct timeval *t2)
 513 {
 514
 515         t1->tv_sec += t2->tv_sec;
 516         t1->tv_usec += t2->tv_usec;
 517         timevalfix(t1);
 518 }
 519 void
 520 timevalsub(
 521         struct timeval *t1,
 522         struct timeval *t2)
 523 {
 524
 525         t1->tv_sec -= t2->tv_sec;
 526         t1->tv_usec -= t2->tv_usec;
 527         timevalfix(t1);
 528 }
 529 void
 530 timevalfix(
 531         struct timeval *t1)
 532 {
 533
 534         if (t1->tv_usec < 0) {
 535                 t1->tv_sec--;
 536                 t1->tv_usec += 1000000;
 537         }
 538         if (t1->tv_usec >= 1000000) {
 539                 t1->tv_sec++;
 540                 t1->tv_usec -= 1000000;
 541         }
 542 }
 543
 544 /*
 545  * Return the best possible estimate of the time in the timeval
 546  * to which tvp points.
 547  */
 548 void
 549 microtime(
 550         struct timeval  *tvp)
 551 {
 552         mach_timespec_t         now = clock_get_calendar_value();
 553
 554         tvp->tv_sec = now.tv_sec;
 555         tvp->tv_usec = now.tv_nsec / NSEC_PER_USEC;
 556 }
 557
 558 void
 559 microuptime(
 560         struct timeval  *tvp)
 561 {
 562         mach_timespec_t         now = clock_get_system_value();
 563
 564         tvp->tv_sec = now.tv_sec;
 565         tvp->tv_usec = now.tv_nsec / NSEC_PER_USEC;
 566 }
 567
 568 /*
 569  * Ditto for timespec.
 570  */
 571 void
 572 nanotime(
 573         struct timespec *tsp)
 574 {
 575         mach_timespec_t         now = clock_get_calendar_value();
 576
 577         tsp->tv_sec = now.tv_sec;
 578         tsp->tv_nsec = now.tv_nsec;
 579 }
 580
 581 void
 582 nanouptime(
 583         struct timespec *tsp)
 584 {
 585         mach_timespec_t         now = clock_get_system_value();
 586
 587         tsp->tv_sec = now.tv_sec;
 588         tsp->tv_nsec = now.tv_nsec;
 589 }
 590
 591 uint64_t
 592 tvtoabstime(
 593         struct timeval  *tvp)
 594 {
 595         uint64_t        result, usresult;
 596
 597         clock_interval_to_absolutetime_interval(
 598                                                 tvp->tv_sec, NSEC_PER_SEC, &result);
 599         clock_interval_to_absolutetime_interval(
 600                                                 tvp->tv_usec, NSEC_PER_USEC, &usresult);
 601
 602         return (result + usresult);
 603 }
 604 void
 605 time_zone_slock_init(void)
 606 {
 607         extern simple_lock_data_t tz_slock;
 608
 609         simple_lock_init(&tz_slock);
 610
 611
 612 }