bsd/kern/kern_time.c

   1 /*
   2  * Copyright (c) 2000-2008 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  29 /*
  30  * Copyright (c) 1982, 1986, 1989, 1993
  31  *      The Regents of the University of California.  All rights reserved.
  32  *
  33  * Redistribution and use in source and binary forms, with or without
  34  * modification, are permitted provided that the following conditions
  35  * are met:
  36  * 1. Redistributions of source code must retain the above copyright
  37  *    notice, this list of conditions and the following disclaimer.
  38  * 2. Redistributions in binary form must reproduce the above copyright
  39  *    notice, this list of conditions and the following disclaimer in the
  40  *    documentation and/or other materials provided with the distribution.
  41  * 3. All advertising materials mentioning features or use of this software
  42  *    must display the following acknowledgement:
  43  *      This product includes software developed by the University of
  44  *      California, Berkeley and its contributors.
  45  * 4. Neither the name of the University nor the names of its contributors
  46  *    may be used to endorse or promote products derived from this software
  47  *    without specific prior written permission.
  48  *
  49  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  59  * SUCH DAMAGE.
  60  *
  61  *      @(#)kern_time.c 8.4 (Berkeley) 5/26/95
  62  */
  63 /*
  64  * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
  65  * support for mandatory and extensible security protections.  This notice
  66  * is included in support of clause 2.2 (b) of the Apple Public License,
  67  * Version 2.0.
  68  */
  69
  70 #include <sys/param.h>
  71 #include <sys/resourcevar.h>
  72 #include <sys/kernel.h>
  73 #include <sys/systm.h>
  74 #include <sys/proc_internal.h>
  75 #include <sys/kauth.h>
  76 #include <sys/vnode.h>
  77 #include <sys/time.h>
  78 #include <sys/priv.h>
  79
  80 #include <sys/mount_internal.h>
  81 #include <sys/sysproto.h>
  82 #include <sys/signalvar.h>
  83 #include <sys/protosw.h> /* for net_uptime2timeval() */
  84
  85 #include <kern/clock.h>
  86 #include <kern/task.h>
  87 #include <kern/thread_call.h>
  88 #if CONFIG_MACF
  89 #include <security/mac_framework.h>
  90 #endif
  91 #include <IOKit/IOBSD.h>
  92 #include <sys/time.h>
  93 #include <kern/remote_time.h>
  94
  95 #define HZ      100     /* XXX */
  96
  97 /* simple lock used to access timezone, tz structure */
  98 static LCK_GRP_DECLARE(tz_slock_grp, "tzlock");
  99 static LCK_SPIN_DECLARE(tz_slock, &tz_slock_grp);
 100
 101 static void             setthetime(
 102         struct timeval  *tv);
 103
 104 static boolean_t timeval_fixusec(struct timeval *t1);
 105
 106 /*
 107  * Time of day and interval timer support.
 108  *
 109  * These routines provide the kernel entry points to get and set
 110  * the time-of-day and per-process interval timers.  Subroutines
 111  * here provide support for adding and subtracting timeval structures
 112  * and decrementing interval timers, optionally reloading the interval
 113  * timers when they expire.
 114  */
 115 /* ARGSUSED */
 116 int
 117 gettimeofday(
 118         struct proc     *p,
 119         struct gettimeofday_args *uap,
 120         __unused int32_t *retval)
 121 {
 122         int error = 0;
 123         struct timezone ltz; /* local copy */
 124         clock_sec_t secs;
 125         clock_usec_t usecs;
 126         uint64_t mach_time;
 127
 128         if (uap->tp || uap->mach_absolute_time) {
 129                 clock_gettimeofday_and_absolute_time(&secs, &usecs, &mach_time);
 130         }
 131
 132         if (uap->tp) {
 133                 /* Casting secs through a uint32_t to match arm64 commpage */
 134                 if (IS_64BIT_PROCESS(p)) {
 135                         struct user64_timeval user_atv = {};
 136                         user_atv.tv_sec = (uint32_t)secs;
 137                         user_atv.tv_usec = usecs;
 138                         error = copyout(&user_atv, uap->tp, sizeof(user_atv));
 139                 } else {
 140                         struct user32_timeval user_atv = {};
 141                         user_atv.tv_sec = (uint32_t)secs;
 142                         user_atv.tv_usec = usecs;
 143                         error = copyout(&user_atv, uap->tp, sizeof(user_atv));
 144                 }
 145                 if (error) {
 146                         return error;
 147                 }
 148         }
 149
 150         if (uap->tzp) {
 151                 lck_spin_lock(&tz_slock);
 152                 ltz = tz;
 153                 lck_spin_unlock(&tz_slock);
 154
 155                 error = copyout((caddr_t)&ltz, CAST_USER_ADDR_T(uap->tzp), sizeof(tz));
 156         }
 157
 158         if (error == 0 && uap->mach_absolute_time) {
 159                 error = copyout(&mach_time, uap->mach_absolute_time, sizeof(mach_time));
 160         }
 161
 162         return error;
 163 }
 164
 165 /*
 166  * XXX Y2038 bug because of setthetime() argument
 167  */
 168 /* ARGSUSED */
 169 int
 170 settimeofday(__unused struct proc *p, struct settimeofday_args  *uap, __unused int32_t *retval)
 171 {
 172         struct timeval atv;
 173         struct timezone atz;
 174         int error;
 175
 176         bzero(&atv, sizeof(atv));
 177
 178         /* Check that this task is entitled to set the time or it is root */
 179         if (!IOTaskHasEntitlement(current_task(), SETTIME_ENTITLEMENT)) {
 180 #if CONFIG_MACF
 181                 error = mac_system_check_settime(kauth_cred_get());
 182                 if (error) {
 183                         return error;
 184                 }
 185 #endif
 186 #if defined(XNU_TARGET_OS_OSX)
 187                 if ((error = suser(kauth_cred_get(), &p->p_acflag))) {
 188                         return error;
 189                 }
 190 #endif
 191         }
 192
 193         /* Verify all parameters before changing time */
 194         if (uap->tv) {
 195                 if (IS_64BIT_PROCESS(p)) {
 196                         struct user64_timeval user_atv;
 197                         error = copyin(uap->tv, &user_atv, sizeof(user_atv));
 198                         atv.tv_sec = (__darwin_time_t)user_atv.tv_sec;
 199                         atv.tv_usec = user_atv.tv_usec;
 200                 } else {
 201                         struct user32_timeval user_atv;
 202                         error = copyin(uap->tv, &user_atv, sizeof(user_atv));
 203                         atv.tv_sec = user_atv.tv_sec;
 204                         atv.tv_usec = user_atv.tv_usec;
 205                 }
 206                 if (error) {
 207                         return error;
 208                 }
 209         }
 210         if (uap->tzp && (error = copyin(uap->tzp, (caddr_t)&atz, sizeof(atz)))) {
 211                 return error;
 212         }
 213         if (uap->tv) {
 214                 /* only positive values of sec/usec are accepted */
 215                 if (atv.tv_sec < 0 || atv.tv_usec < 0) {
 216                         return EPERM;
 217                 }
 218                 if (!timeval_fixusec(&atv)) {
 219                         return EPERM;
 220                 }
 221                 setthetime(&atv);
 222         }
 223         if (uap->tzp) {
 224                 lck_spin_lock(&tz_slock);
 225                 tz = atz;
 226                 lck_spin_unlock(&tz_slock);
 227         }
 228         return 0;
 229 }
 230
 231 static void
 232 setthetime(
 233         struct timeval  *tv)
 234 {
 235         clock_set_calendar_microtime(tv->tv_sec, tv->tv_usec);
 236 }
 237
 238 /*
 239  *      Verify the calendar value.  If negative,
 240  *      reset to zero (the epoch).
 241  */
 242 void
 243 inittodr(
 244         __unused time_t base)
 245 {
 246         struct timeval  tv;
 247
 248         /*
 249          * Assertion:
 250          * The calendar has already been
 251          * set up from the platform clock.
 252          *
 253          * The value returned by microtime()
 254          * is gotten from the calendar.
 255          */
 256         microtime(&tv);
 257
 258         if (tv.tv_sec < 0 || tv.tv_usec < 0) {
 259                 printf("WARNING: preposterous time in Real Time Clock");
 260                 tv.tv_sec = 0;          /* the UNIX epoch */
 261                 tv.tv_usec = 0;
 262                 setthetime(&tv);
 263                 printf(" -- CHECK AND RESET THE DATE!\n");
 264         }
 265 }
 266
 267 time_t
 268 boottime_sec(void)
 269 {
 270         clock_sec_t             secs;
 271         clock_nsec_t    nanosecs;
 272
 273         clock_get_boottime_nanotime(&secs, &nanosecs);
 274         return secs;
 275 }
 276
 277 void
 278 boottime_timeval(struct timeval *tv)
 279 {
 280         clock_sec_t             secs;
 281         clock_usec_t    microsecs;
 282
 283         clock_get_boottime_microtime(&secs, &microsecs);
 284
 285         tv->tv_sec = secs;
 286         tv->tv_usec = microsecs;
 287 }
 288
 289 /*
 290  * Get value of an interval timer.  The process virtual and
 291  * profiling virtual time timers are kept internally in the
 292  * way they are specified externally: in time until they expire.
 293  *
 294  * The real time interval timer expiration time (p_rtime)
 295  * is kept as an absolute time rather than as a delta, so that
 296  * it is easy to keep periodic real-time signals from drifting.
 297  *
 298  * The real time timer is processed by a callout routine.
 299  * Since a callout may be delayed in real time due to
 300  * other processing in the system, it is possible for the real
 301  * time callout routine (realitexpire, given below), to be delayed
 302  * in real time past when it is supposed to occur.  It does not
 303  * suffice, therefore, to reload the real time .it_value from the
 304  * real time .it_interval.  Rather, we compute the next time in
 305  * absolute time when the timer should go off.
 306  *
 307  * Returns:     0                       Success
 308  *              EINVAL                  Invalid argument
 309  *      copyout:EFAULT                  Bad address
 310  */
 311 /* ARGSUSED */
 312 int
 313 getitimer(struct proc *p, struct getitimer_args *uap, __unused int32_t *retval)
 314 {
 315         struct itimerval aitv;
 316
 317         if (uap->which > ITIMER_PROF) {
 318                 return EINVAL;
 319         }
 320
 321         bzero(&aitv, sizeof(aitv));
 322
 323         proc_spinlock(p);
 324         switch (uap->which) {
 325         case ITIMER_REAL:
 326                 /*
 327                  * If time for real time timer has passed return 0,
 328                  * else return difference between current time and
 329                  * time for the timer to go off.
 330                  */
 331                 aitv = p->p_realtimer;
 332                 if (timerisset(&p->p_rtime)) {
 333                         struct timeval          now;
 334
 335                         microuptime(&now);
 336                         if (timercmp(&p->p_rtime, &now, <)) {
 337                                 timerclear(&aitv.it_value);
 338                         } else {
 339                                 aitv.it_value = p->p_rtime;
 340                                 timevalsub(&aitv.it_value, &now);
 341                         }
 342                 } else {
 343                         timerclear(&aitv.it_value);
 344                 }
 345                 break;
 346
 347         case ITIMER_VIRTUAL:
 348                 aitv = p->p_vtimer_user;
 349                 break;
 350
 351         case ITIMER_PROF:
 352                 aitv = p->p_vtimer_prof;
 353                 break;
 354         }
 355
 356         proc_spinunlock(p);
 357
 358         if (IS_64BIT_PROCESS(p)) {
 359                 struct user64_itimerval user_itv;
 360                 bzero(&user_itv, sizeof(user_itv));
 361                 user_itv.it_interval.tv_sec = aitv.it_interval.tv_sec;
 362                 user_itv.it_interval.tv_usec = aitv.it_interval.tv_usec;
 363                 user_itv.it_value.tv_sec = aitv.it_value.tv_sec;
 364                 user_itv.it_value.tv_usec = aitv.it_value.tv_usec;
 365                 return copyout((caddr_t)&user_itv, uap->itv, sizeof(user_itv));
 366         } else {
 367                 struct user32_itimerval user_itv;
 368                 bzero(&user_itv, sizeof(user_itv));
 369                 user_itv.it_interval.tv_sec = (user32_time_t)aitv.it_interval.tv_sec;
 370                 user_itv.it_interval.tv_usec = aitv.it_interval.tv_usec;
 371                 user_itv.it_value.tv_sec = (user32_time_t)aitv.it_value.tv_sec;
 372                 user_itv.it_value.tv_usec = aitv.it_value.tv_usec;
 373                 return copyout((caddr_t)&user_itv, uap->itv, sizeof(user_itv));
 374         }
 375 }
 376
 377 /*
 378  * Returns:     0                       Success
 379  *              EINVAL                  Invalid argument
 380  *      copyin:EFAULT                   Bad address
 381  *      getitimer:EINVAL                Invalid argument
 382  *      getitimer:EFAULT                Bad address
 383  */
 384 /* ARGSUSED */
 385 int
 386 setitimer(struct proc *p, struct setitimer_args *uap, int32_t *retval)
 387 {
 388         struct itimerval aitv;
 389         user_addr_t itvp;
 390         int error;
 391
 392         bzero(&aitv, sizeof(aitv));
 393
 394         if (uap->which > ITIMER_PROF) {
 395                 return EINVAL;
 396         }
 397         if ((itvp = uap->itv)) {
 398                 if (IS_64BIT_PROCESS(p)) {
 399                         struct user64_itimerval user_itv;
 400                         if ((error = copyin(itvp, (caddr_t)&user_itv, sizeof(user_itv)))) {
 401                                 return error;
 402                         }
 403                         aitv.it_interval.tv_sec = (__darwin_time_t)user_itv.it_interval.tv_sec;
 404                         aitv.it_interval.tv_usec = user_itv.it_interval.tv_usec;
 405                         aitv.it_value.tv_sec = (__darwin_time_t)user_itv.it_value.tv_sec;
 406                         aitv.it_value.tv_usec = user_itv.it_value.tv_usec;
 407                 } else {
 408                         struct user32_itimerval user_itv;
 409                         if ((error = copyin(itvp, (caddr_t)&user_itv, sizeof(user_itv)))) {
 410                                 return error;
 411                         }
 412                         aitv.it_interval.tv_sec = user_itv.it_interval.tv_sec;
 413                         aitv.it_interval.tv_usec = user_itv.it_interval.tv_usec;
 414                         aitv.it_value.tv_sec = user_itv.it_value.tv_sec;
 415                         aitv.it_value.tv_usec = user_itv.it_value.tv_usec;
 416                 }
 417         }
 418         if ((uap->itv = uap->oitv) && (error = getitimer(p, (struct getitimer_args *)uap, retval))) {
 419                 return error;
 420         }
 421         if (itvp == 0) {
 422                 return 0;
 423         }
 424         if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) {
 425                 return EINVAL;
 426         }
 427
 428         switch (uap->which) {
 429         case ITIMER_REAL:
 430                 proc_spinlock(p);
 431                 if (timerisset(&aitv.it_value)) {
 432                         microuptime(&p->p_rtime);
 433                         timevaladd(&p->p_rtime, &aitv.it_value);
 434                         p->p_realtimer = aitv;
 435                         if (!thread_call_enter_delayed_with_leeway(p->p_rcall, NULL,
 436                             tvtoabstime(&p->p_rtime), 0, THREAD_CALL_DELAY_USER_NORMAL)) {
 437                                 p->p_ractive++;
 438                         }
 439                 } else {
 440                         timerclear(&p->p_rtime);
 441                         p->p_realtimer = aitv;
 442                         if (thread_call_cancel(p->p_rcall)) {
 443                                 p->p_ractive--;
 444                         }
 445                 }
 446                 proc_spinunlock(p);
 447
 448                 break;
 449
 450
 451         case ITIMER_VIRTUAL:
 452                 if (timerisset(&aitv.it_value)) {
 453                         task_vtimer_set(p->task, TASK_VTIMER_USER);
 454                 } else {
 455                         task_vtimer_clear(p->task, TASK_VTIMER_USER);
 456                 }
 457
 458                 proc_spinlock(p);
 459                 p->p_vtimer_user = aitv;
 460                 proc_spinunlock(p);
 461                 break;
 462
 463         case ITIMER_PROF:
 464                 if (timerisset(&aitv.it_value)) {
 465                         task_vtimer_set(p->task, TASK_VTIMER_PROF);
 466                 } else {
 467                         task_vtimer_clear(p->task, TASK_VTIMER_PROF);
 468                 }
 469
 470                 proc_spinlock(p);
 471                 p->p_vtimer_prof = aitv;
 472                 proc_spinunlock(p);
 473                 break;
 474         }
 475
 476         return 0;
 477 }
 478
 479 /*
 480  * Real interval timer expired:
 481  * send process whose timer expired an alarm signal.
 482  * If time is not set up to reload, then just return.
 483  * Else compute next time timer should go off which is > current time.
 484  * This is where delay in processing this timeout causes multiple
 485  * SIGALRM calls to be compressed into one.
 486  */
 487 void
 488 realitexpire(
 489         struct proc *p)
 490 {
 491         struct proc *r;
 492         struct timeval t;
 493
 494         r = proc_find(p->p_pid);
 495
 496         proc_spinlock(p);
 497
 498         assert(p->p_ractive > 0);
 499
 500         if (--p->p_ractive > 0 || r != p) {
 501                 /*
 502                  * bail, because either proc is exiting
 503                  * or there's another active thread call
 504                  */
 505                 proc_spinunlock(p);
 506
 507                 if (r != NULL) {
 508                         proc_rele(r);
 509                 }
 510                 return;
 511         }
 512
 513         if (!timerisset(&p->p_realtimer.it_interval)) {
 514                 /*
 515                  * p_realtimer was cleared while this call was pending,
 516                  * send one last SIGALRM, but don't re-arm
 517                  */
 518                 timerclear(&p->p_rtime);
 519                 proc_spinunlock(p);
 520
 521                 psignal(p, SIGALRM);
 522                 proc_rele(p);
 523                 return;
 524         }
 525
 526         proc_spinunlock(p);
 527
 528         /*
 529          * Send the signal before re-arming the next thread call,
 530          * so in case psignal blocks, we won't create yet another thread call.
 531          */
 532
 533         psignal(p, SIGALRM);
 534
 535         proc_spinlock(p);
 536
 537         /* Should we still re-arm the next thread call? */
 538         if (!timerisset(&p->p_realtimer.it_interval)) {
 539                 timerclear(&p->p_rtime);
 540                 proc_spinunlock(p);
 541
 542                 proc_rele(p);
 543                 return;
 544         }
 545
 546         microuptime(&t);
 547         timevaladd(&p->p_rtime, &p->p_realtimer.it_interval);
 548
 549         if (timercmp(&p->p_rtime, &t, <=)) {
 550                 if ((p->p_rtime.tv_sec + 2) >= t.tv_sec) {
 551                         for (;;) {
 552                                 timevaladd(&p->p_rtime, &p->p_realtimer.it_interval);
 553                                 if (timercmp(&p->p_rtime, &t, >)) {
 554                                         break;
 555                                 }
 556                         }
 557                 } else {
 558                         p->p_rtime = p->p_realtimer.it_interval;
 559                         timevaladd(&p->p_rtime, &t);
 560                 }
 561         }
 562
 563         assert(p->p_rcall != NULL);
 564
 565         if (!thread_call_enter_delayed_with_leeway(p->p_rcall, NULL, tvtoabstime(&p->p_rtime), 0,
 566             THREAD_CALL_DELAY_USER_NORMAL)) {
 567                 p->p_ractive++;
 568         }
 569
 570         proc_spinunlock(p);
 571
 572         proc_rele(p);
 573 }
 574
 575 /*
 576  * Called once in proc_exit to clean up after an armed or pending realitexpire
 577  *
 578  * This will only be called after the proc refcount is drained,
 579  * so realitexpire cannot be currently holding a proc ref.
 580  * i.e. it will/has gotten PROC_NULL from proc_find.
 581  */
 582 void
 583 proc_free_realitimer(proc_t p)
 584 {
 585         proc_spinlock(p);
 586
 587         assert(p->p_rcall != NULL);
 588         assert(p->p_refcount == 0);
 589
 590         timerclear(&p->p_realtimer.it_interval);
 591
 592         if (thread_call_cancel(p->p_rcall)) {
 593                 assert(p->p_ractive > 0);
 594                 p->p_ractive--;
 595         }
 596
 597         while (p->p_ractive > 0) {
 598                 proc_spinunlock(p);
 599
 600                 delay(1);
 601
 602                 proc_spinlock(p);
 603         }
 604
 605         thread_call_t call = p->p_rcall;
 606         p->p_rcall = NULL;
 607
 608         proc_spinunlock(p);
 609
 610         thread_call_free(call);
 611 }
 612
 613 /*
 614  * Check that a proposed value to load into the .it_value or
 615  * .it_interval part of an interval timer is acceptable.
 616  */
 617 int
 618 itimerfix(
 619         struct timeval *tv)
 620 {
 621         if (tv->tv_sec < 0 || tv->tv_sec > 100000000 ||
 622             tv->tv_usec < 0 || tv->tv_usec >= 1000000) {
 623                 return EINVAL;
 624         }
 625         return 0;
 626 }
 627
 628 int
 629 timespec_is_valid(const struct timespec *ts)
 630 {
 631         /* The INT32_MAX limit ensures the timespec is safe for clock_*() functions
 632          * which accept 32-bit ints. */
 633         if (ts->tv_sec < 0 || ts->tv_sec > INT32_MAX ||
 634             ts->tv_nsec < 0 || (unsigned long long)ts->tv_nsec > NSEC_PER_SEC) {
 635                 return 0;
 636         }
 637         return 1;
 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  */
 650 int
 651 itimerdecr(proc_t p,
 652     struct itimerval *itp, int usec)
 653 {
 654         proc_spinlock(p);
 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 (timerisset(&itp->it_value)) {
 668                 proc_spinunlock(p);
 669                 return 1;
 670         }
 671         /* expired, exactly at end of interval */
 672 expire:
 673         if (timerisset(&itp->it_interval)) {
 674                 itp->it_value = itp->it_interval;
 675                 if (itp->it_value.tv_sec > 0) {
 676                         itp->it_value.tv_usec -= usec;
 677                         if (itp->it_value.tv_usec < 0) {
 678                                 itp->it_value.tv_usec += 1000000;
 679                                 itp->it_value.tv_sec--;
 680                         }
 681                 }
 682         } else {
 683                 itp->it_value.tv_usec = 0;              /* sec is already 0 */
 684         }
 685         proc_spinunlock(p);
 686         return 0;
 687 }
 688
 689 /*
 690  * Add and subtract routines for timevals.
 691  * N.B.: subtract routine doesn't deal with
 692  * results which are before the beginning,
 693  * it just gets very confused in this case.
 694  * Caveat emptor.
 695  */
 696 void
 697 timevaladd(
 698         struct timeval *t1,
 699         struct timeval *t2)
 700 {
 701         t1->tv_sec += t2->tv_sec;
 702         t1->tv_usec += t2->tv_usec;
 703         timevalfix(t1);
 704 }
 705 void
 706 timevalsub(
 707         struct timeval *t1,
 708         struct timeval *t2)
 709 {
 710         t1->tv_sec -= t2->tv_sec;
 711         t1->tv_usec -= t2->tv_usec;
 712         timevalfix(t1);
 713 }
 714 void
 715 timevalfix(
 716         struct timeval *t1)
 717 {
 718         if (t1->tv_usec < 0) {
 719                 t1->tv_sec--;
 720                 t1->tv_usec += 1000000;
 721         }
 722         if (t1->tv_usec >= 1000000) {
 723                 t1->tv_sec++;
 724                 t1->tv_usec -= 1000000;
 725         }
 726 }
 727
 728 static boolean_t
 729 timeval_fixusec(
 730         struct timeval *t1)
 731 {
 732         assert(t1->tv_usec >= 0);
 733         assert(t1->tv_sec >= 0);
 734
 735         if (t1->tv_usec >= 1000000) {
 736                 if (os_add_overflow(t1->tv_sec, t1->tv_usec / 1000000, &t1->tv_sec)) {
 737                         return FALSE;
 738                 }
 739                 t1->tv_usec = t1->tv_usec % 1000000;
 740         }
 741
 742         return TRUE;
 743 }
 744
 745 /*
 746  * Return the best possible estimate of the time in the timeval
 747  * to which tvp points.
 748  */
 749 void
 750 microtime(
 751         struct timeval  *tvp)
 752 {
 753         clock_sec_t             tv_sec;
 754         clock_usec_t    tv_usec;
 755
 756         clock_get_calendar_microtime(&tv_sec, &tv_usec);
 757
 758         tvp->tv_sec = tv_sec;
 759         tvp->tv_usec = tv_usec;
 760 }
 761
 762 void
 763 microtime_with_abstime(
 764         struct timeval  *tvp, uint64_t *abstime)
 765 {
 766         clock_sec_t             tv_sec;
 767         clock_usec_t    tv_usec;
 768
 769         clock_get_calendar_absolute_and_microtime(&tv_sec, &tv_usec, abstime);
 770
 771         tvp->tv_sec = tv_sec;
 772         tvp->tv_usec = tv_usec;
 773 }
 774
 775 void
 776 microuptime(
 777         struct timeval  *tvp)
 778 {
 779         clock_sec_t             tv_sec;
 780         clock_usec_t    tv_usec;
 781
 782         clock_get_system_microtime(&tv_sec, &tv_usec);
 783
 784         tvp->tv_sec = tv_sec;
 785         tvp->tv_usec = tv_usec;
 786 }
 787
 788 /*
 789  * Ditto for timespec.
 790  */
 791 void
 792 nanotime(
 793         struct timespec *tsp)
 794 {
 795         clock_sec_t             tv_sec;
 796         clock_nsec_t    tv_nsec;
 797
 798         clock_get_calendar_nanotime(&tv_sec, &tv_nsec);
 799
 800         tsp->tv_sec = tv_sec;
 801         tsp->tv_nsec = tv_nsec;
 802 }
 803
 804 void
 805 nanouptime(
 806         struct timespec *tsp)
 807 {
 808         clock_sec_t             tv_sec;
 809         clock_nsec_t    tv_nsec;
 810
 811         clock_get_system_nanotime(&tv_sec, &tv_nsec);
 812
 813         tsp->tv_sec = tv_sec;
 814         tsp->tv_nsec = tv_nsec;
 815 }
 816
 817 uint64_t
 818 tvtoabstime(
 819         struct timeval  *tvp)
 820 {
 821         uint64_t        result, usresult;
 822
 823         clock_interval_to_absolutetime_interval(
 824                 (uint32_t)tvp->tv_sec, NSEC_PER_SEC, &result);
 825         clock_interval_to_absolutetime_interval(
 826                 tvp->tv_usec, NSEC_PER_USEC, &usresult);
 827
 828         return result + usresult;
 829 }
 830
 831 uint64_t
 832 tstoabstime(struct timespec *ts)
 833 {
 834         uint64_t abstime_s, abstime_ns;
 835         clock_interval_to_absolutetime_interval((uint32_t)ts->tv_sec, NSEC_PER_SEC, &abstime_s);
 836         clock_interval_to_absolutetime_interval((uint32_t)ts->tv_nsec, 1, &abstime_ns);
 837         return abstime_s + abstime_ns;
 838 }
 839
 840 #if NETWORKING
 841 /*
 842  * ratecheck(): simple time-based rate-limit checking.
 843  */
 844 int
 845 ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
 846 {
 847         struct timeval tv, delta;
 848         int rv = 0;
 849
 850         net_uptime2timeval(&tv);
 851         delta = tv;
 852         timevalsub(&delta, lasttime);
 853
 854         /*
 855          * check for 0,0 is so that the message will be seen at least once,
 856          * even if interval is huge.
 857          */
 858         if (timevalcmp(&delta, mininterval, >=) ||
 859             (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
 860                 *lasttime = tv;
 861                 rv = 1;
 862         }
 863
 864         return rv;
 865 }
 866
 867 /*
 868  * ppsratecheck(): packets (or events) per second limitation.
 869  */
 870 int
 871 ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
 872 {
 873         struct timeval tv, delta;
 874         int rv;
 875
 876         net_uptime2timeval(&tv);
 877
 878         timersub(&tv, lasttime, &delta);
 879
 880         /*
 881          * Check for 0,0 so that the message will be seen at least once.
 882          * If more than one second has passed since the last update of
 883          * lasttime, reset the counter.
 884          *
 885          * we do increment *curpps even in *curpps < maxpps case, as some may
 886          * try to use *curpps for stat purposes as well.
 887          */
 888         if ((lasttime->tv_sec == 0 && lasttime->tv_usec == 0) ||
 889             delta.tv_sec >= 1) {
 890                 *lasttime = tv;
 891                 *curpps = 0;
 892                 rv = 1;
 893         } else if (maxpps < 0) {
 894                 rv = 1;
 895         } else if (*curpps < maxpps) {
 896                 rv = 1;
 897         } else {
 898                 rv = 0;
 899         }
 900
 901 #if 1 /* DIAGNOSTIC? */
 902         /* be careful about wrap-around */
 903         if (*curpps + 1 > 0) {
 904                 *curpps = *curpps + 1;
 905         }
 906 #else
 907         /*
 908          * assume that there's not too many calls to this function.
 909          * not sure if the assumption holds, as it depends on *caller's*
 910          * behavior, not the behavior of this function.
 911          * IMHO it is wrong to make assumption on the caller's behavior,
 912          * so the above #if is #if 1, not #ifdef DIAGNOSTIC.
 913          */
 914         *curpps = *curpps + 1;
 915 #endif
 916
 917         return rv;
 918 }
 919 #endif /* NETWORKING */
 920
 921 int
 922 __mach_bridge_remote_time(__unused struct proc *p, struct __mach_bridge_remote_time_args *mbrt_args, uint64_t *retval)
 923 {
 924         *retval = mach_bridge_remote_time(mbrt_args->local_timestamp);
 925         return 0;
 926 }