The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_time.c

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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  * 4. Neither the name of the University nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  *      @(#)kern_time.c 8.1 (Berkeley) 6/10/93
   30  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD: releng/8.3/sys/kern/kern_time.c 199583 2009-11-20 15:27:52Z jhb $");
   34 
   35 #include <sys/param.h>
   36 #include <sys/systm.h>
   37 #include <sys/limits.h>
   38 #include <sys/clock.h>
   39 #include <sys/lock.h>
   40 #include <sys/mutex.h>
   41 #include <sys/sysproto.h>
   42 #include <sys/eventhandler.h>
   43 #include <sys/resourcevar.h>
   44 #include <sys/signalvar.h>
   45 #include <sys/kernel.h>
   46 #include <sys/syscallsubr.h>
   47 #include <sys/sysctl.h>
   48 #include <sys/sysent.h>
   49 #include <sys/priv.h>
   50 #include <sys/proc.h>
   51 #include <sys/posix4.h>
   52 #include <sys/time.h>
   53 #include <sys/timers.h>
   54 #include <sys/timetc.h>
   55 #include <sys/vnode.h>
   56 
   57 #include <vm/vm.h>
   58 #include <vm/vm_extern.h>
   59 
   60 #define MAX_CLOCKS      (CLOCK_MONOTONIC+1)
   61 
   62 static struct kclock    posix_clocks[MAX_CLOCKS];
   63 static uma_zone_t       itimer_zone = NULL;
   64 
   65 /*
   66  * Time of day and interval timer support.
   67  *
   68  * These routines provide the kernel entry points to get and set
   69  * the time-of-day and per-process interval timers.  Subroutines
   70  * here provide support for adding and subtracting timeval structures
   71  * and decrementing interval timers, optionally reloading the interval
   72  * timers when they expire.
   73  */
   74 
   75 static int      settime(struct thread *, struct timeval *);
   76 static void     timevalfix(struct timeval *);
   77 
   78 static void     itimer_start(void);
   79 static int      itimer_init(void *, int, int);
   80 static void     itimer_fini(void *, int);
   81 static void     itimer_enter(struct itimer *);
   82 static void     itimer_leave(struct itimer *);
   83 static struct itimer *itimer_find(struct proc *, int);
   84 static void     itimers_alloc(struct proc *);
   85 static void     itimers_event_hook_exec(void *arg, struct proc *p, struct image_params *imgp);
   86 static void     itimers_event_hook_exit(void *arg, struct proc *p);
   87 static int      realtimer_create(struct itimer *);
   88 static int      realtimer_gettime(struct itimer *, struct itimerspec *);
   89 static int      realtimer_settime(struct itimer *, int,
   90                         struct itimerspec *, struct itimerspec *);
   91 static int      realtimer_delete(struct itimer *);
   92 static void     realtimer_clocktime(clockid_t, struct timespec *);
   93 static void     realtimer_expire(void *);
   94 static int      kern_timer_create(struct thread *, clockid_t,
   95                         struct sigevent *, int *, int);
   96 static int      kern_timer_delete(struct thread *, int);
   97 
   98 int             register_posix_clock(int, struct kclock *);
   99 void            itimer_fire(struct itimer *it);
  100 int             itimespecfix(struct timespec *ts);
  101 
  102 #define CLOCK_CALL(clock, call, arglist)                \
  103         ((*posix_clocks[clock].call) arglist)
  104 
  105 SYSINIT(posix_timer, SI_SUB_P1003_1B, SI_ORDER_FIRST+4, itimer_start, NULL);
  106 
  107 
  108 static int
  109 settime(struct thread *td, struct timeval *tv)
  110 {
  111         struct timeval delta, tv1, tv2;
  112         static struct timeval maxtime, laststep;
  113         struct timespec ts;
  114         int s;
  115 
  116         s = splclock();
  117         microtime(&tv1);
  118         delta = *tv;
  119         timevalsub(&delta, &tv1);
  120 
  121         /*
  122          * If the system is secure, we do not allow the time to be 
  123          * set to a value earlier than 1 second less than the highest
  124          * time we have yet seen. The worst a miscreant can do in
  125          * this circumstance is "freeze" time. He couldn't go
  126          * back to the past.
  127          *
  128          * We similarly do not allow the clock to be stepped more
  129          * than one second, nor more than once per second. This allows
  130          * a miscreant to make the clock march double-time, but no worse.
  131          */
  132         if (securelevel_gt(td->td_ucred, 1) != 0) {
  133                 if (delta.tv_sec < 0 || delta.tv_usec < 0) {
  134                         /*
  135                          * Update maxtime to latest time we've seen.
  136                          */
  137                         if (tv1.tv_sec > maxtime.tv_sec)
  138                                 maxtime = tv1;
  139                         tv2 = *tv;
  140                         timevalsub(&tv2, &maxtime);
  141                         if (tv2.tv_sec < -1) {
  142                                 tv->tv_sec = maxtime.tv_sec - 1;
  143                                 printf("Time adjustment clamped to -1 second\n");
  144                         }
  145                 } else {
  146                         if (tv1.tv_sec == laststep.tv_sec) {
  147                                 splx(s);
  148                                 return (EPERM);
  149                         }
  150                         if (delta.tv_sec > 1) {
  151                                 tv->tv_sec = tv1.tv_sec + 1;
  152                                 printf("Time adjustment clamped to +1 second\n");
  153                         }
  154                         laststep = *tv;
  155                 }
  156         }
  157 
  158         ts.tv_sec = tv->tv_sec;
  159         ts.tv_nsec = tv->tv_usec * 1000;
  160         mtx_lock(&Giant);
  161         tc_setclock(&ts);
  162         resettodr();
  163         mtx_unlock(&Giant);
  164         return (0);
  165 }
  166 
  167 #ifndef _SYS_SYSPROTO_H_
  168 struct clock_gettime_args {
  169         clockid_t clock_id;
  170         struct  timespec *tp;
  171 };
  172 #endif
  173 /* ARGSUSED */
  174 int
  175 clock_gettime(struct thread *td, struct clock_gettime_args *uap)
  176 {
  177         struct timespec ats;
  178         int error;
  179 
  180         error = kern_clock_gettime(td, uap->clock_id, &ats);
  181         if (error == 0)
  182                 error = copyout(&ats, uap->tp, sizeof(ats));
  183 
  184         return (error);
  185 }
  186 
  187 int
  188 kern_clock_gettime(struct thread *td, clockid_t clock_id, struct timespec *ats)
  189 {
  190         struct timeval sys, user;
  191         struct proc *p;
  192         uint64_t runtime, curtime, switchtime;
  193 
  194         p = td->td_proc;
  195         switch (clock_id) {
  196         case CLOCK_REALTIME:            /* Default to precise. */
  197         case CLOCK_REALTIME_PRECISE:
  198                 nanotime(ats);
  199                 break;
  200         case CLOCK_REALTIME_FAST:
  201                 getnanotime(ats);
  202                 break;
  203         case CLOCK_VIRTUAL:
  204                 PROC_LOCK(p);
  205                 PROC_SLOCK(p);
  206                 calcru(p, &user, &sys);
  207                 PROC_SUNLOCK(p);
  208                 PROC_UNLOCK(p);
  209                 TIMEVAL_TO_TIMESPEC(&user, ats);
  210                 break;
  211         case CLOCK_PROF:
  212                 PROC_LOCK(p);
  213                 PROC_SLOCK(p);
  214                 calcru(p, &user, &sys);
  215                 PROC_SUNLOCK(p);
  216                 PROC_UNLOCK(p);
  217                 timevaladd(&user, &sys);
  218                 TIMEVAL_TO_TIMESPEC(&user, ats);
  219                 break;
  220         case CLOCK_MONOTONIC:           /* Default to precise. */
  221         case CLOCK_MONOTONIC_PRECISE:
  222         case CLOCK_UPTIME:
  223         case CLOCK_UPTIME_PRECISE:
  224                 nanouptime(ats);
  225                 break;
  226         case CLOCK_UPTIME_FAST:
  227         case CLOCK_MONOTONIC_FAST:
  228                 getnanouptime(ats);
  229                 break;
  230         case CLOCK_SECOND:
  231                 ats->tv_sec = time_second;
  232                 ats->tv_nsec = 0;
  233                 break;
  234         case CLOCK_THREAD_CPUTIME_ID:
  235                 critical_enter();
  236                 switchtime = PCPU_GET(switchtime);
  237                 curtime = cpu_ticks();
  238                 runtime = td->td_runtime;
  239                 critical_exit();
  240                 runtime = cputick2usec(runtime + curtime - switchtime);
  241                 ats->tv_sec = runtime / 1000000;
  242                 ats->tv_nsec = runtime % 1000000 * 1000;
  243                 break;
  244         default:
  245                 return (EINVAL);
  246         }
  247         return (0);
  248 }
  249 
  250 #ifndef _SYS_SYSPROTO_H_
  251 struct clock_settime_args {
  252         clockid_t clock_id;
  253         const struct    timespec *tp;
  254 };
  255 #endif
  256 /* ARGSUSED */
  257 int
  258 clock_settime(struct thread *td, struct clock_settime_args *uap)
  259 {
  260         struct timespec ats;
  261         int error;
  262 
  263         if ((error = copyin(uap->tp, &ats, sizeof(ats))) != 0)
  264                 return (error);
  265         return (kern_clock_settime(td, uap->clock_id, &ats));
  266 }
  267 
  268 int
  269 kern_clock_settime(struct thread *td, clockid_t clock_id, struct timespec *ats)
  270 {
  271         struct timeval atv;
  272         int error;
  273 
  274         if ((error = priv_check(td, PRIV_CLOCK_SETTIME)) != 0)
  275                 return (error);
  276         if (clock_id != CLOCK_REALTIME)
  277                 return (EINVAL);
  278         if (ats->tv_nsec < 0 || ats->tv_nsec >= 1000000000)
  279                 return (EINVAL);
  280         /* XXX Don't convert nsec->usec and back */
  281         TIMESPEC_TO_TIMEVAL(&atv, ats);
  282         error = settime(td, &atv);
  283         return (error);
  284 }
  285 
  286 #ifndef _SYS_SYSPROTO_H_
  287 struct clock_getres_args {
  288         clockid_t clock_id;
  289         struct  timespec *tp;
  290 };
  291 #endif
  292 int
  293 clock_getres(struct thread *td, struct clock_getres_args *uap)
  294 {
  295         struct timespec ts;
  296         int error;
  297 
  298         if (uap->tp == NULL)
  299                 return (0);
  300 
  301         error = kern_clock_getres(td, uap->clock_id, &ts);
  302         if (error == 0)
  303                 error = copyout(&ts, uap->tp, sizeof(ts));
  304         return (error);
  305 }
  306 
  307 int
  308 kern_clock_getres(struct thread *td, clockid_t clock_id, struct timespec *ts)
  309 {
  310 
  311         ts->tv_sec = 0;
  312         switch (clock_id) {
  313         case CLOCK_REALTIME:
  314         case CLOCK_REALTIME_FAST:
  315         case CLOCK_REALTIME_PRECISE:
  316         case CLOCK_MONOTONIC:
  317         case CLOCK_MONOTONIC_FAST:
  318         case CLOCK_MONOTONIC_PRECISE:
  319         case CLOCK_UPTIME:
  320         case CLOCK_UPTIME_FAST:
  321         case CLOCK_UPTIME_PRECISE:
  322                 /*
  323                  * Round up the result of the division cheaply by adding 1.
  324                  * Rounding up is especially important if rounding down
  325                  * would give 0.  Perfect rounding is unimportant.
  326                  */
  327                 ts->tv_nsec = 1000000000 / tc_getfrequency() + 1;
  328                 break;
  329         case CLOCK_VIRTUAL:
  330         case CLOCK_PROF:
  331                 /* Accurately round up here because we can do so cheaply. */
  332                 ts->tv_nsec = (1000000000 + hz - 1) / hz;
  333                 break;
  334         case CLOCK_SECOND:
  335                 ts->tv_sec = 1;
  336                 ts->tv_nsec = 0;
  337                 break;
  338         case CLOCK_THREAD_CPUTIME_ID:
  339                 /* sync with cputick2usec */
  340                 ts->tv_nsec = 1000000 / cpu_tickrate();
  341                 if (ts->tv_nsec == 0)
  342                         ts->tv_nsec = 1000;
  343                 break;
  344         default:
  345                 return (EINVAL);
  346         }
  347         return (0);
  348 }
  349 
  350 static int nanowait;
  351 
  352 int
  353 kern_nanosleep(struct thread *td, struct timespec *rqt, struct timespec *rmt)
  354 {
  355         struct timespec ts, ts2, ts3;
  356         struct timeval tv;
  357         int error;
  358 
  359         if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)
  360                 return (EINVAL);
  361         if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0))
  362                 return (0);
  363         getnanouptime(&ts);
  364         timespecadd(&ts, rqt);
  365         TIMESPEC_TO_TIMEVAL(&tv, rqt);
  366         for (;;) {
  367                 error = tsleep(&nanowait, PWAIT | PCATCH, "nanslp",
  368                     tvtohz(&tv));
  369                 getnanouptime(&ts2);
  370                 if (error != EWOULDBLOCK) {
  371                         if (error == ERESTART)
  372                                 error = EINTR;
  373                         if (rmt != NULL) {
  374                                 timespecsub(&ts, &ts2);
  375                                 if (ts.tv_sec < 0)
  376                                         timespecclear(&ts);
  377                                 *rmt = ts;
  378                         }
  379                         return (error);
  380                 }
  381                 if (timespeccmp(&ts2, &ts, >=))
  382                         return (0);
  383                 ts3 = ts;
  384                 timespecsub(&ts3, &ts2);
  385                 TIMESPEC_TO_TIMEVAL(&tv, &ts3);
  386         }
  387 }
  388 
  389 #ifndef _SYS_SYSPROTO_H_
  390 struct nanosleep_args {
  391         struct  timespec *rqtp;
  392         struct  timespec *rmtp;
  393 };
  394 #endif
  395 /* ARGSUSED */
  396 int
  397 nanosleep(struct thread *td, struct nanosleep_args *uap)
  398 {
  399         struct timespec rmt, rqt;
  400         int error;
  401 
  402         error = copyin(uap->rqtp, &rqt, sizeof(rqt));
  403         if (error)
  404                 return (error);
  405 
  406         if (uap->rmtp &&
  407             !useracc((caddr_t)uap->rmtp, sizeof(rmt), VM_PROT_WRITE))
  408                         return (EFAULT);
  409         error = kern_nanosleep(td, &rqt, &rmt);
  410         if (error && uap->rmtp) {
  411                 int error2;
  412 
  413                 error2 = copyout(&rmt, uap->rmtp, sizeof(rmt));
  414                 if (error2)
  415                         error = error2;
  416         }
  417         return (error);
  418 }
  419 
  420 #ifndef _SYS_SYSPROTO_H_
  421 struct gettimeofday_args {
  422         struct  timeval *tp;
  423         struct  timezone *tzp;
  424 };
  425 #endif
  426 /* ARGSUSED */
  427 int
  428 gettimeofday(struct thread *td, struct gettimeofday_args *uap)
  429 {
  430         struct timeval atv;
  431         struct timezone rtz;
  432         int error = 0;
  433 
  434         if (uap->tp) {
  435                 microtime(&atv);
  436                 error = copyout(&atv, uap->tp, sizeof (atv));
  437         }
  438         if (error == 0 && uap->tzp != NULL) {
  439                 rtz.tz_minuteswest = tz_minuteswest;
  440                 rtz.tz_dsttime = tz_dsttime;
  441                 error = copyout(&rtz, uap->tzp, sizeof (rtz));
  442         }
  443         return (error);
  444 }
  445 
  446 #ifndef _SYS_SYSPROTO_H_
  447 struct settimeofday_args {
  448         struct  timeval *tv;
  449         struct  timezone *tzp;
  450 };
  451 #endif
  452 /* ARGSUSED */
  453 int
  454 settimeofday(struct thread *td, struct settimeofday_args *uap)
  455 {
  456         struct timeval atv, *tvp;
  457         struct timezone atz, *tzp;
  458         int error;
  459 
  460         if (uap->tv) {
  461                 error = copyin(uap->tv, &atv, sizeof(atv));
  462                 if (error)
  463                         return (error);
  464                 tvp = &atv;
  465         } else
  466                 tvp = NULL;
  467         if (uap->tzp) {
  468                 error = copyin(uap->tzp, &atz, sizeof(atz));
  469                 if (error)
  470                         return (error);
  471                 tzp = &atz;
  472         } else
  473                 tzp = NULL;
  474         return (kern_settimeofday(td, tvp, tzp));
  475 }
  476 
  477 int
  478 kern_settimeofday(struct thread *td, struct timeval *tv, struct timezone *tzp)
  479 {
  480         int error;
  481 
  482         error = priv_check(td, PRIV_SETTIMEOFDAY);
  483         if (error)
  484                 return (error);
  485         /* Verify all parameters before changing time. */
  486         if (tv) {
  487                 if (tv->tv_usec < 0 || tv->tv_usec >= 1000000)
  488                         return (EINVAL);
  489                 error = settime(td, tv);
  490         }
  491         if (tzp && error == 0) {
  492                 tz_minuteswest = tzp->tz_minuteswest;
  493                 tz_dsttime = tzp->tz_dsttime;
  494         }
  495         return (error);
  496 }
  497 
  498 /*
  499  * Get value of an interval timer.  The process virtual and profiling virtual
  500  * time timers are kept in the p_stats area, since they can be swapped out.
  501  * These are kept internally in the way they are specified externally: in
  502  * time until they expire.
  503  *
  504  * The real time interval timer is kept in the process table slot for the
  505  * process, and its value (it_value) is kept as an absolute time rather than
  506  * as a delta, so that it is easy to keep periodic real-time signals from
  507  * drifting.
  508  *
  509  * Virtual time timers are processed in the hardclock() routine of
  510  * kern_clock.c.  The real time timer is processed by a timeout routine,
  511  * called from the softclock() routine.  Since a callout may be delayed in
  512  * real time due to interrupt processing in the system, it is possible for
  513  * the real time timeout routine (realitexpire, given below), to be delayed
  514  * in real time past when it is supposed to occur.  It does not suffice,
  515  * therefore, to reload the real timer .it_value from the real time timers
  516  * .it_interval.  Rather, we compute the next time in absolute time the timer
  517  * should go off.
  518  */
  519 #ifndef _SYS_SYSPROTO_H_
  520 struct getitimer_args {
  521         u_int   which;
  522         struct  itimerval *itv;
  523 };
  524 #endif
  525 int
  526 getitimer(struct thread *td, struct getitimer_args *uap)
  527 {
  528         struct itimerval aitv;
  529         int error;
  530 
  531         error = kern_getitimer(td, uap->which, &aitv);
  532         if (error != 0)
  533                 return (error);
  534         return (copyout(&aitv, uap->itv, sizeof (struct itimerval)));
  535 }
  536 
  537 int
  538 kern_getitimer(struct thread *td, u_int which, struct itimerval *aitv)
  539 {
  540         struct proc *p = td->td_proc;
  541         struct timeval ctv;
  542 
  543         if (which > ITIMER_PROF)
  544                 return (EINVAL);
  545 
  546         if (which == ITIMER_REAL) {
  547                 /*
  548                  * Convert from absolute to relative time in .it_value
  549                  * part of real time timer.  If time for real time timer
  550                  * has passed return 0, else return difference between
  551                  * current time and time for the timer to go off.
  552                  */
  553                 PROC_LOCK(p);
  554                 *aitv = p->p_realtimer;
  555                 PROC_UNLOCK(p);
  556                 if (timevalisset(&aitv->it_value)) {
  557                         getmicrouptime(&ctv);
  558                         if (timevalcmp(&aitv->it_value, &ctv, <))
  559                                 timevalclear(&aitv->it_value);
  560                         else
  561                                 timevalsub(&aitv->it_value, &ctv);
  562                 }
  563         } else {
  564                 PROC_SLOCK(p);
  565                 *aitv = p->p_stats->p_timer[which];
  566                 PROC_SUNLOCK(p);
  567         }
  568         return (0);
  569 }
  570 
  571 #ifndef _SYS_SYSPROTO_H_
  572 struct setitimer_args {
  573         u_int   which;
  574         struct  itimerval *itv, *oitv;
  575 };
  576 #endif
  577 int
  578 setitimer(struct thread *td, struct setitimer_args *uap)
  579 {
  580         struct itimerval aitv, oitv;
  581         int error;
  582 
  583         if (uap->itv == NULL) {
  584                 uap->itv = uap->oitv;
  585                 return (getitimer(td, (struct getitimer_args *)uap));
  586         }
  587 
  588         if ((error = copyin(uap->itv, &aitv, sizeof(struct itimerval))))
  589                 return (error);
  590         error = kern_setitimer(td, uap->which, &aitv, &oitv);
  591         if (error != 0 || uap->oitv == NULL)
  592                 return (error);
  593         return (copyout(&oitv, uap->oitv, sizeof(struct itimerval)));
  594 }
  595 
  596 int
  597 kern_setitimer(struct thread *td, u_int which, struct itimerval *aitv,
  598     struct itimerval *oitv)
  599 {
  600         struct proc *p = td->td_proc;
  601         struct timeval ctv;
  602 
  603         if (aitv == NULL)
  604                 return (kern_getitimer(td, which, oitv));
  605 
  606         if (which > ITIMER_PROF)
  607                 return (EINVAL);
  608         if (itimerfix(&aitv->it_value))
  609                 return (EINVAL);
  610         if (!timevalisset(&aitv->it_value))
  611                 timevalclear(&aitv->it_interval);
  612         else if (itimerfix(&aitv->it_interval))
  613                 return (EINVAL);
  614 
  615         if (which == ITIMER_REAL) {
  616                 PROC_LOCK(p);
  617                 if (timevalisset(&p->p_realtimer.it_value))
  618                         callout_stop(&p->p_itcallout);
  619                 getmicrouptime(&ctv);
  620                 if (timevalisset(&aitv->it_value)) {
  621                         callout_reset(&p->p_itcallout, tvtohz(&aitv->it_value),
  622                             realitexpire, p);
  623                         timevaladd(&aitv->it_value, &ctv);
  624                 }
  625                 *oitv = p->p_realtimer;
  626                 p->p_realtimer = *aitv;
  627                 PROC_UNLOCK(p);
  628                 if (timevalisset(&oitv->it_value)) {
  629                         if (timevalcmp(&oitv->it_value, &ctv, <))
  630                                 timevalclear(&oitv->it_value);
  631                         else
  632                                 timevalsub(&oitv->it_value, &ctv);
  633                 }
  634         } else {
  635                 PROC_SLOCK(p);
  636                 *oitv = p->p_stats->p_timer[which];
  637                 p->p_stats->p_timer[which] = *aitv;
  638                 PROC_SUNLOCK(p);
  639         }
  640         return (0);
  641 }
  642 
  643 /*
  644  * Real interval timer expired:
  645  * send process whose timer expired an alarm signal.
  646  * If time is not set up to reload, then just return.
  647  * Else compute next time timer should go off which is > current time.
  648  * This is where delay in processing this timeout causes multiple
  649  * SIGALRM calls to be compressed into one.
  650  * tvtohz() always adds 1 to allow for the time until the next clock
  651  * interrupt being strictly less than 1 clock tick, but we don't want
  652  * that here since we want to appear to be in sync with the clock
  653  * interrupt even when we're delayed.
  654  */
  655 void
  656 realitexpire(void *arg)
  657 {
  658         struct proc *p;
  659         struct timeval ctv, ntv;
  660 
  661         p = (struct proc *)arg;
  662         PROC_LOCK(p);
  663         psignal(p, SIGALRM);
  664         if (!timevalisset(&p->p_realtimer.it_interval)) {
  665                 timevalclear(&p->p_realtimer.it_value);
  666                 if (p->p_flag & P_WEXIT)
  667                         wakeup(&p->p_itcallout);
  668                 PROC_UNLOCK(p);
  669                 return;
  670         }
  671         for (;;) {
  672                 timevaladd(&p->p_realtimer.it_value,
  673                     &p->p_realtimer.it_interval);
  674                 getmicrouptime(&ctv);
  675                 if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) {
  676                         ntv = p->p_realtimer.it_value;
  677                         timevalsub(&ntv, &ctv);
  678                         callout_reset(&p->p_itcallout, tvtohz(&ntv) - 1,
  679                             realitexpire, p);
  680                         PROC_UNLOCK(p);
  681                         return;
  682                 }
  683         }
  684         /*NOTREACHED*/
  685 }
  686 
  687 /*
  688  * Check that a proposed value to load into the .it_value or
  689  * .it_interval part of an interval timer is acceptable, and
  690  * fix it to have at least minimal value (i.e. if it is less
  691  * than the resolution of the clock, round it up.)
  692  */
  693 int
  694 itimerfix(struct timeval *tv)
  695 {
  696 
  697         if (tv->tv_sec < 0 || tv->tv_usec < 0 || tv->tv_usec >= 1000000)
  698                 return (EINVAL);
  699         if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)
  700                 tv->tv_usec = tick;
  701         return (0);
  702 }
  703 
  704 /*
  705  * Decrement an interval timer by a specified number
  706  * of microseconds, which must be less than a second,
  707  * i.e. < 1000000.  If the timer expires, then reload
  708  * it.  In this case, carry over (usec - old value) to
  709  * reduce the value reloaded into the timer so that
  710  * the timer does not drift.  This routine assumes
  711  * that it is called in a context where the timers
  712  * on which it is operating cannot change in value.
  713  */
  714 int
  715 itimerdecr(struct itimerval *itp, int usec)
  716 {
  717 
  718         if (itp->it_value.tv_usec < usec) {
  719                 if (itp->it_value.tv_sec == 0) {
  720                         /* expired, and already in next interval */
  721                         usec -= itp->it_value.tv_usec;
  722                         goto expire;
  723                 }
  724                 itp->it_value.tv_usec += 1000000;
  725                 itp->it_value.tv_sec--;
  726         }
  727         itp->it_value.tv_usec -= usec;
  728         usec = 0;
  729         if (timevalisset(&itp->it_value))
  730                 return (1);
  731         /* expired, exactly at end of interval */
  732 expire:
  733         if (timevalisset(&itp->it_interval)) {
  734                 itp->it_value = itp->it_interval;
  735                 itp->it_value.tv_usec -= usec;
  736                 if (itp->it_value.tv_usec < 0) {
  737                         itp->it_value.tv_usec += 1000000;
  738                         itp->it_value.tv_sec--;
  739                 }
  740         } else
  741                 itp->it_value.tv_usec = 0;              /* sec is already 0 */
  742         return (0);
  743 }
  744 
  745 /*
  746  * Add and subtract routines for timevals.
  747  * N.B.: subtract routine doesn't deal with
  748  * results which are before the beginning,
  749  * it just gets very confused in this case.
  750  * Caveat emptor.
  751  */
  752 void
  753 timevaladd(struct timeval *t1, const struct timeval *t2)
  754 {
  755 
  756         t1->tv_sec += t2->tv_sec;
  757         t1->tv_usec += t2->tv_usec;
  758         timevalfix(t1);
  759 }
  760 
  761 void
  762 timevalsub(struct timeval *t1, const struct timeval *t2)
  763 {
  764 
  765         t1->tv_sec -= t2->tv_sec;
  766         t1->tv_usec -= t2->tv_usec;
  767         timevalfix(t1);
  768 }
  769 
  770 static void
  771 timevalfix(struct timeval *t1)
  772 {
  773 
  774         if (t1->tv_usec < 0) {
  775                 t1->tv_sec--;
  776                 t1->tv_usec += 1000000;
  777         }
  778         if (t1->tv_usec >= 1000000) {
  779                 t1->tv_sec++;
  780                 t1->tv_usec -= 1000000;
  781         }
  782 }
  783 
  784 /*
  785  * ratecheck(): simple time-based rate-limit checking.
  786  */
  787 int
  788 ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
  789 {
  790         struct timeval tv, delta;
  791         int rv = 0;
  792 
  793         getmicrouptime(&tv);            /* NB: 10ms precision */
  794         delta = tv;
  795         timevalsub(&delta, lasttime);
  796 
  797         /*
  798          * check for 0,0 is so that the message will be seen at least once,
  799          * even if interval is huge.
  800          */
  801         if (timevalcmp(&delta, mininterval, >=) ||
  802             (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
  803                 *lasttime = tv;
  804                 rv = 1;
  805         }
  806 
  807         return (rv);
  808 }
  809 
  810 /*
  811  * ppsratecheck(): packets (or events) per second limitation.
  812  *
  813  * Return 0 if the limit is to be enforced (e.g. the caller
  814  * should drop a packet because of the rate limitation).
  815  *
  816  * maxpps of 0 always causes zero to be returned.  maxpps of -1
  817  * always causes 1 to be returned; this effectively defeats rate
  818  * limiting.
  819  *
  820  * Note that we maintain the struct timeval for compatibility
  821  * with other bsd systems.  We reuse the storage and just monitor
  822  * clock ticks for minimal overhead.  
  823  */
  824 int
  825 ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
  826 {
  827         int now;
  828 
  829         /*
  830          * Reset the last time and counter if this is the first call
  831          * or more than a second has passed since the last update of
  832          * lasttime.
  833          */
  834         now = ticks;
  835         if (lasttime->tv_sec == 0 || (u_int)(now - lasttime->tv_sec) >= hz) {
  836                 lasttime->tv_sec = now;
  837                 *curpps = 1;
  838                 return (maxpps != 0);
  839         } else {
  840                 (*curpps)++;            /* NB: ignore potential overflow */
  841                 return (maxpps < 0 || *curpps < maxpps);
  842         }
  843 }
  844 
  845 static void
  846 itimer_start(void)
  847 {
  848         struct kclock rt_clock = {
  849                 .timer_create  = realtimer_create,
  850                 .timer_delete  = realtimer_delete,
  851                 .timer_settime = realtimer_settime,
  852                 .timer_gettime = realtimer_gettime,
  853                 .event_hook    = NULL
  854         };
  855 
  856         itimer_zone = uma_zcreate("itimer", sizeof(struct itimer),
  857                 NULL, NULL, itimer_init, itimer_fini, UMA_ALIGN_PTR, 0);
  858         register_posix_clock(CLOCK_REALTIME,  &rt_clock);
  859         register_posix_clock(CLOCK_MONOTONIC, &rt_clock);
  860         p31b_setcfg(CTL_P1003_1B_TIMERS, 200112L);
  861         p31b_setcfg(CTL_P1003_1B_DELAYTIMER_MAX, INT_MAX);
  862         p31b_setcfg(CTL_P1003_1B_TIMER_MAX, TIMER_MAX);
  863         EVENTHANDLER_REGISTER(process_exit, itimers_event_hook_exit,
  864                 (void *)ITIMER_EV_EXIT, EVENTHANDLER_PRI_ANY);
  865         EVENTHANDLER_REGISTER(process_exec, itimers_event_hook_exec,
  866                 (void *)ITIMER_EV_EXEC, EVENTHANDLER_PRI_ANY);
  867 }
  868 
  869 int
  870 register_posix_clock(int clockid, struct kclock *clk)
  871 {
  872         if ((unsigned)clockid >= MAX_CLOCKS) {
  873                 printf("%s: invalid clockid\n", __func__);
  874                 return (0);
  875         }
  876         posix_clocks[clockid] = *clk;
  877         return (1);
  878 }
  879 
  880 static int
  881 itimer_init(void *mem, int size, int flags)
  882 {
  883         struct itimer *it;
  884 
  885         it = (struct itimer *)mem;
  886         mtx_init(&it->it_mtx, "itimer lock", NULL, MTX_DEF);
  887         return (0);
  888 }
  889 
  890 static void
  891 itimer_fini(void *mem, int size)
  892 {
  893         struct itimer *it;
  894 
  895         it = (struct itimer *)mem;
  896         mtx_destroy(&it->it_mtx);
  897 }
  898 
  899 static void
  900 itimer_enter(struct itimer *it)
  901 {
  902 
  903         mtx_assert(&it->it_mtx, MA_OWNED);
  904         it->it_usecount++;
  905 }
  906 
  907 static void
  908 itimer_leave(struct itimer *it)
  909 {
  910 
  911         mtx_assert(&it->it_mtx, MA_OWNED);
  912         KASSERT(it->it_usecount > 0, ("invalid it_usecount"));
  913 
  914         if (--it->it_usecount == 0 && (it->it_flags & ITF_WANTED) != 0)
  915                 wakeup(it);
  916 }
  917 
  918 #ifndef _SYS_SYSPROTO_H_
  919 struct ktimer_create_args {
  920         clockid_t clock_id;
  921         struct sigevent * evp;
  922         int * timerid;
  923 };
  924 #endif
  925 int
  926 ktimer_create(struct thread *td, struct ktimer_create_args *uap)
  927 {
  928         struct sigevent *evp1, ev;
  929         int id;
  930         int error;
  931 
  932         if (uap->evp != NULL) {
  933                 error = copyin(uap->evp, &ev, sizeof(ev));
  934                 if (error != 0)
  935                         return (error);
  936                 evp1 = &ev;
  937         } else
  938                 evp1 = NULL;
  939 
  940         error = kern_timer_create(td, uap->clock_id, evp1, &id, -1);
  941 
  942         if (error == 0) {
  943                 error = copyout(&id, uap->timerid, sizeof(int));
  944                 if (error != 0)
  945                         kern_timer_delete(td, id);
  946         }
  947         return (error);
  948 }
  949 
  950 static int
  951 kern_timer_create(struct thread *td, clockid_t clock_id,
  952         struct sigevent *evp, int *timerid, int preset_id)
  953 {
  954         struct proc *p = td->td_proc;
  955         struct itimer *it;
  956         int id;
  957         int error;
  958 
  959         if (clock_id < 0 || clock_id >= MAX_CLOCKS)
  960                 return (EINVAL);
  961 
  962         if (posix_clocks[clock_id].timer_create == NULL)
  963                 return (EINVAL);
  964 
  965         if (evp != NULL) {
  966                 if (evp->sigev_notify != SIGEV_NONE &&
  967                     evp->sigev_notify != SIGEV_SIGNAL &&
  968                     evp->sigev_notify != SIGEV_THREAD_ID)
  969                         return (EINVAL);
  970                 if ((evp->sigev_notify == SIGEV_SIGNAL ||
  971                      evp->sigev_notify == SIGEV_THREAD_ID) &&
  972                         !_SIG_VALID(evp->sigev_signo))
  973                         return (EINVAL);
  974         }
  975         
  976         if (p->p_itimers == NULL)
  977                 itimers_alloc(p);
  978         
  979         it = uma_zalloc(itimer_zone, M_WAITOK);
  980         it->it_flags = 0;
  981         it->it_usecount = 0;
  982         it->it_active = 0;
  983         timespecclear(&it->it_time.it_value);
  984         timespecclear(&it->it_time.it_interval);
  985         it->it_overrun = 0;
  986         it->it_overrun_last = 0;
  987         it->it_clockid = clock_id;
  988         it->it_timerid = -1;
  989         it->it_proc = p;
  990         ksiginfo_init(&it->it_ksi);
  991         it->it_ksi.ksi_flags |= KSI_INS | KSI_EXT;
  992         error = CLOCK_CALL(clock_id, timer_create, (it));
  993         if (error != 0)
  994                 goto out;
  995 
  996         PROC_LOCK(p);
  997         if (preset_id != -1) {
  998                 KASSERT(preset_id >= 0 && preset_id < 3, ("invalid preset_id"));
  999                 id = preset_id;
 1000                 if (p->p_itimers->its_timers[id] != NULL) {
 1001                         PROC_UNLOCK(p);
 1002                         error = 0;
 1003                         goto out;
 1004                 }
 1005         } else {
 1006                 /*
 1007                  * Find a free timer slot, skipping those reserved
 1008                  * for setitimer().
 1009                  */
 1010                 for (id = 3; id < TIMER_MAX; id++)
 1011                         if (p->p_itimers->its_timers[id] == NULL)
 1012                                 break;
 1013                 if (id == TIMER_MAX) {
 1014                         PROC_UNLOCK(p);
 1015                         error = EAGAIN;
 1016                         goto out;
 1017                 }
 1018         }
 1019         it->it_timerid = id;
 1020         p->p_itimers->its_timers[id] = it;
 1021         if (evp != NULL)
 1022                 it->it_sigev = *evp;
 1023         else {
 1024                 it->it_sigev.sigev_notify = SIGEV_SIGNAL;
 1025                 switch (clock_id) {
 1026                 default:
 1027                 case CLOCK_REALTIME:
 1028                         it->it_sigev.sigev_signo = SIGALRM;
 1029                         break;
 1030                 case CLOCK_VIRTUAL:
 1031                         it->it_sigev.sigev_signo = SIGVTALRM;
 1032                         break;
 1033                 case CLOCK_PROF:
 1034                         it->it_sigev.sigev_signo = SIGPROF;
 1035                         break;
 1036                 }
 1037                 it->it_sigev.sigev_value.sival_int = id;
 1038         }
 1039 
 1040         if (it->it_sigev.sigev_notify == SIGEV_SIGNAL ||
 1041             it->it_sigev.sigev_notify == SIGEV_THREAD_ID) {
 1042                 it->it_ksi.ksi_signo = it->it_sigev.sigev_signo;
 1043                 it->it_ksi.ksi_code = SI_TIMER;
 1044                 it->it_ksi.ksi_value = it->it_sigev.sigev_value;
 1045                 it->it_ksi.ksi_timerid = id;
 1046         }
 1047         PROC_UNLOCK(p);
 1048         *timerid = id;
 1049         return (0);
 1050 
 1051 out:
 1052         ITIMER_LOCK(it);
 1053         CLOCK_CALL(it->it_clockid, timer_delete, (it));
 1054         ITIMER_UNLOCK(it);
 1055         uma_zfree(itimer_zone, it);
 1056         return (error);
 1057 }
 1058 
 1059 #ifndef _SYS_SYSPROTO_H_
 1060 struct ktimer_delete_args {
 1061         int timerid;
 1062 };
 1063 #endif
 1064 int
 1065 ktimer_delete(struct thread *td, struct ktimer_delete_args *uap)
 1066 {
 1067         return (kern_timer_delete(td, uap->timerid));
 1068 }
 1069 
 1070 static struct itimer *
 1071 itimer_find(struct proc *p, int timerid)
 1072 {
 1073         struct itimer *it;
 1074 
 1075         PROC_LOCK_ASSERT(p, MA_OWNED);
 1076         if ((p->p_itimers == NULL) ||
 1077             (timerid < 0) || (timerid >= TIMER_MAX) ||
 1078             (it = p->p_itimers->its_timers[timerid]) == NULL) {
 1079                 return (NULL);
 1080         }
 1081         ITIMER_LOCK(it);
 1082         if ((it->it_flags & ITF_DELETING) != 0) {
 1083                 ITIMER_UNLOCK(it);
 1084                 it = NULL;
 1085         }
 1086         return (it);
 1087 }
 1088 
 1089 static int
 1090 kern_timer_delete(struct thread *td, int timerid)
 1091 {
 1092         struct proc *p = td->td_proc;
 1093         struct itimer *it;
 1094 
 1095         PROC_LOCK(p);
 1096         it = itimer_find(p, timerid);
 1097         if (it == NULL) {
 1098                 PROC_UNLOCK(p);
 1099                 return (EINVAL);
 1100         }
 1101         PROC_UNLOCK(p);
 1102 
 1103         it->it_flags |= ITF_DELETING;
 1104         while (it->it_usecount > 0) {
 1105                 it->it_flags |= ITF_WANTED;
 1106                 msleep(it, &it->it_mtx, PPAUSE, "itimer", 0);
 1107         }
 1108         it->it_flags &= ~ITF_WANTED;
 1109         CLOCK_CALL(it->it_clockid, timer_delete, (it));
 1110         ITIMER_UNLOCK(it);
 1111 
 1112         PROC_LOCK(p);
 1113         if (KSI_ONQ(&it->it_ksi))
 1114                 sigqueue_take(&it->it_ksi);
 1115         p->p_itimers->its_timers[timerid] = NULL;
 1116         PROC_UNLOCK(p);
 1117         uma_zfree(itimer_zone, it);
 1118         return (0);
 1119 }
 1120 
 1121 #ifndef _SYS_SYSPROTO_H_
 1122 struct ktimer_settime_args {
 1123         int timerid;
 1124         int flags;
 1125         const struct itimerspec * value;
 1126         struct itimerspec * ovalue;
 1127 };
 1128 #endif
 1129 int
 1130 ktimer_settime(struct thread *td, struct ktimer_settime_args *uap)
 1131 {
 1132         struct proc *p = td->td_proc;
 1133         struct itimer *it;
 1134         struct itimerspec val, oval, *ovalp;
 1135         int error;
 1136 
 1137         error = copyin(uap->value, &val, sizeof(val));
 1138         if (error != 0)
 1139                 return (error);
 1140         
 1141         if (uap->ovalue != NULL)
 1142                 ovalp = &oval;
 1143         else
 1144                 ovalp = NULL;
 1145 
 1146         PROC_LOCK(p);
 1147         if (uap->timerid < 3 ||
 1148             (it = itimer_find(p, uap->timerid)) == NULL) {
 1149                 PROC_UNLOCK(p);
 1150                 error = EINVAL;
 1151         } else {
 1152                 PROC_UNLOCK(p);
 1153                 itimer_enter(it);
 1154                 error = CLOCK_CALL(it->it_clockid, timer_settime,
 1155                                 (it, uap->flags, &val, ovalp));
 1156                 itimer_leave(it);
 1157                 ITIMER_UNLOCK(it);
 1158         }
 1159         if (error == 0 && uap->ovalue != NULL)
 1160                 error = copyout(ovalp, uap->ovalue, sizeof(*ovalp));
 1161         return (error);
 1162 }
 1163 
 1164 #ifndef _SYS_SYSPROTO_H_
 1165 struct ktimer_gettime_args {
 1166         int timerid;
 1167         struct itimerspec * value;
 1168 };
 1169 #endif
 1170 int
 1171 ktimer_gettime(struct thread *td, struct ktimer_gettime_args *uap)
 1172 {
 1173         struct proc *p = td->td_proc;
 1174         struct itimer *it;
 1175         struct itimerspec val;
 1176         int error;
 1177 
 1178         PROC_LOCK(p);
 1179         if (uap->timerid < 3 ||
 1180            (it = itimer_find(p, uap->timerid)) == NULL) {
 1181                 PROC_UNLOCK(p);
 1182                 error = EINVAL;
 1183         } else {
 1184                 PROC_UNLOCK(p);
 1185                 itimer_enter(it);
 1186                 error = CLOCK_CALL(it->it_clockid, timer_gettime,
 1187                                 (it, &val));
 1188                 itimer_leave(it);
 1189                 ITIMER_UNLOCK(it);
 1190         }
 1191         if (error == 0)
 1192                 error = copyout(&val, uap->value, sizeof(val));
 1193         return (error);
 1194 }
 1195 
 1196 #ifndef _SYS_SYSPROTO_H_
 1197 struct timer_getoverrun_args {
 1198         int timerid;
 1199 };
 1200 #endif
 1201 int
 1202 ktimer_getoverrun(struct thread *td, struct ktimer_getoverrun_args *uap)
 1203 {
 1204         struct proc *p = td->td_proc;
 1205         struct itimer *it;
 1206         int error ;
 1207 
 1208         PROC_LOCK(p);
 1209         if (uap->timerid < 3 ||
 1210             (it = itimer_find(p, uap->timerid)) == NULL) {
 1211                 PROC_UNLOCK(p);
 1212                 error = EINVAL;
 1213         } else {
 1214                 td->td_retval[0] = it->it_overrun_last;
 1215                 ITIMER_UNLOCK(it);
 1216                 PROC_UNLOCK(p);
 1217                 error = 0;
 1218         }
 1219         return (error);
 1220 }
 1221 
 1222 static int
 1223 realtimer_create(struct itimer *it)
 1224 {
 1225         callout_init_mtx(&it->it_callout, &it->it_mtx, 0);
 1226         return (0);
 1227 }
 1228 
 1229 static int
 1230 realtimer_delete(struct itimer *it)
 1231 {
 1232         mtx_assert(&it->it_mtx, MA_OWNED);
 1233         
 1234         /*
 1235          * clear timer's value and interval to tell realtimer_expire
 1236          * to not rearm the timer.
 1237          */
 1238         timespecclear(&it->it_time.it_value);
 1239         timespecclear(&it->it_time.it_interval);
 1240         ITIMER_UNLOCK(it);
 1241         callout_drain(&it->it_callout);
 1242         ITIMER_LOCK(it);
 1243         return (0);
 1244 }
 1245 
 1246 static int
 1247 realtimer_gettime(struct itimer *it, struct itimerspec *ovalue)
 1248 {
 1249         struct timespec cts;
 1250 
 1251         mtx_assert(&it->it_mtx, MA_OWNED);
 1252 
 1253         realtimer_clocktime(it->it_clockid, &cts);
 1254         *ovalue = it->it_time;
 1255         if (ovalue->it_value.tv_sec != 0 || ovalue->it_value.tv_nsec != 0) {
 1256                 timespecsub(&ovalue->it_value, &cts);
 1257                 if (ovalue->it_value.tv_sec < 0 ||
 1258                     (ovalue->it_value.tv_sec == 0 &&
 1259                      ovalue->it_value.tv_nsec == 0)) {
 1260                         ovalue->it_value.tv_sec  = 0;
 1261                         ovalue->it_value.tv_nsec = 1;
 1262                 }
 1263         }
 1264         return (0);
 1265 }
 1266 
 1267 static int
 1268 realtimer_settime(struct itimer *it, int flags,
 1269         struct itimerspec *value, struct itimerspec *ovalue)
 1270 {
 1271         struct timespec cts, ts;
 1272         struct timeval tv;
 1273         struct itimerspec val;
 1274 
 1275         mtx_assert(&it->it_mtx, MA_OWNED);
 1276 
 1277         val = *value;
 1278         if (itimespecfix(&val.it_value))
 1279                 return (EINVAL);
 1280 
 1281         if (timespecisset(&val.it_value)) {
 1282                 if (itimespecfix(&val.it_interval))
 1283                         return (EINVAL);
 1284         } else {
 1285                 timespecclear(&val.it_interval);
 1286         }
 1287         
 1288         if (ovalue != NULL)
 1289                 realtimer_gettime(it, ovalue);
 1290 
 1291         it->it_time = val;
 1292         if (timespecisset(&val.it_value)) {
 1293                 realtimer_clocktime(it->it_clockid, &cts);
 1294                 ts = val.it_value;
 1295                 if ((flags & TIMER_ABSTIME) == 0) {
 1296                         /* Convert to absolute time. */
 1297                         timespecadd(&it->it_time.it_value, &cts);
 1298                 } else {
 1299                         timespecsub(&ts, &cts);
 1300                         /*
 1301                          * We don't care if ts is negative, tztohz will
 1302                          * fix it.
 1303                          */
 1304                 }
 1305                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
 1306                 callout_reset(&it->it_callout, tvtohz(&tv),
 1307                         realtimer_expire, it);
 1308         } else {
 1309                 callout_stop(&it->it_callout);
 1310         }
 1311 
 1312         return (0);
 1313 }
 1314 
 1315 static void
 1316 realtimer_clocktime(clockid_t id, struct timespec *ts)
 1317 {
 1318         if (id == CLOCK_REALTIME)
 1319                 getnanotime(ts);
 1320         else    /* CLOCK_MONOTONIC */
 1321                 getnanouptime(ts);
 1322 }
 1323 
 1324 int
 1325 itimer_accept(struct proc *p, int timerid, ksiginfo_t *ksi)
 1326 {
 1327         struct itimer *it;
 1328 
 1329         PROC_LOCK_ASSERT(p, MA_OWNED);
 1330         it = itimer_find(p, timerid);
 1331         if (it != NULL) {
 1332                 ksi->ksi_overrun = it->it_overrun;
 1333                 it->it_overrun_last = it->it_overrun;
 1334                 it->it_overrun = 0;
 1335                 ITIMER_UNLOCK(it);
 1336                 return (0);
 1337         }
 1338         return (EINVAL);
 1339 }
 1340 
 1341 int
 1342 itimespecfix(struct timespec *ts)
 1343 {
 1344 
 1345         if (ts->tv_sec < 0 || ts->tv_nsec < 0 || ts->tv_nsec >= 1000000000)
 1346                 return (EINVAL);
 1347         if (ts->tv_sec == 0 && ts->tv_nsec != 0 && ts->tv_nsec < tick * 1000)
 1348                 ts->tv_nsec = tick * 1000;
 1349         return (0);
 1350 }
 1351 
 1352 /* Timeout callback for realtime timer */
 1353 static void
 1354 realtimer_expire(void *arg)
 1355 {
 1356         struct timespec cts, ts;
 1357         struct timeval tv;
 1358         struct itimer *it;
 1359 
 1360         it = (struct itimer *)arg;
 1361 
 1362         realtimer_clocktime(it->it_clockid, &cts);
 1363         /* Only fire if time is reached. */
 1364         if (timespeccmp(&cts, &it->it_time.it_value, >=)) {
 1365                 if (timespecisset(&it->it_time.it_interval)) {
 1366                         timespecadd(&it->it_time.it_value,
 1367                                     &it->it_time.it_interval);
 1368                         while (timespeccmp(&cts, &it->it_time.it_value, >=)) {
 1369                                 if (it->it_overrun < INT_MAX)
 1370                                         it->it_overrun++;
 1371                                 else
 1372                                         it->it_ksi.ksi_errno = ERANGE;
 1373                                 timespecadd(&it->it_time.it_value,
 1374                                             &it->it_time.it_interval);
 1375                         }
 1376                 } else {
 1377                         /* single shot timer ? */
 1378                         timespecclear(&it->it_time.it_value);
 1379                 }
 1380                 if (timespecisset(&it->it_time.it_value)) {
 1381                         ts = it->it_time.it_value;
 1382                         timespecsub(&ts, &cts);
 1383                         TIMESPEC_TO_TIMEVAL(&tv, &ts);
 1384                         callout_reset(&it->it_callout, tvtohz(&tv),
 1385                                  realtimer_expire, it);
 1386                 }
 1387                 itimer_enter(it);
 1388                 ITIMER_UNLOCK(it);
 1389                 itimer_fire(it);
 1390                 ITIMER_LOCK(it);
 1391                 itimer_leave(it);
 1392         } else if (timespecisset(&it->it_time.it_value)) {
 1393                 ts = it->it_time.it_value;
 1394                 timespecsub(&ts, &cts);
 1395                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
 1396                 callout_reset(&it->it_callout, tvtohz(&tv), realtimer_expire,
 1397                         it);
 1398         }
 1399 }
 1400 
 1401 void
 1402 itimer_fire(struct itimer *it)
 1403 {
 1404         struct proc *p = it->it_proc;
 1405         int ret;
 1406 
 1407         if (it->it_sigev.sigev_notify == SIGEV_SIGNAL ||
 1408             it->it_sigev.sigev_notify == SIGEV_THREAD_ID) {
 1409                 PROC_LOCK(p);
 1410                 if (!KSI_ONQ(&it->it_ksi)) {
 1411                         it->it_ksi.ksi_errno = 0;
 1412                         ret = psignal_event(p, &it->it_sigev, &it->it_ksi);
 1413                         if (__predict_false(ret != 0)) {
 1414                                 it->it_overrun++;
 1415                                 /*
 1416                                  * Broken userland code, thread went
 1417                                  * away, disarm the timer.
 1418                                  */
 1419                                 if (ret == ESRCH) {
 1420                                         ITIMER_LOCK(it);
 1421                                         timespecclear(&it->it_time.it_value);
 1422                                         timespecclear(&it->it_time.it_interval);
 1423                                         callout_stop(&it->it_callout);
 1424                                         ITIMER_UNLOCK(it);
 1425                                 }
 1426                         }
 1427                 } else {
 1428                         if (it->it_overrun < INT_MAX)
 1429                                 it->it_overrun++;
 1430                         else
 1431                                 it->it_ksi.ksi_errno = ERANGE;
 1432                 }
 1433                 PROC_UNLOCK(p);
 1434         }
 1435 }
 1436 
 1437 static void
 1438 itimers_alloc(struct proc *p)
 1439 {
 1440         struct itimers *its;
 1441         int i;
 1442 
 1443         its = malloc(sizeof (struct itimers), M_SUBPROC, M_WAITOK | M_ZERO);
 1444         LIST_INIT(&its->its_virtual);
 1445         LIST_INIT(&its->its_prof);
 1446         TAILQ_INIT(&its->its_worklist);
 1447         for (i = 0; i < TIMER_MAX; i++)
 1448                 its->its_timers[i] = NULL;
 1449         PROC_LOCK(p);
 1450         if (p->p_itimers == NULL) {
 1451                 p->p_itimers = its;
 1452                 PROC_UNLOCK(p);
 1453         }
 1454         else {
 1455                 PROC_UNLOCK(p);
 1456                 free(its, M_SUBPROC);
 1457         }
 1458 }
 1459 
 1460 static void
 1461 itimers_event_hook_exec(void *arg, struct proc *p, struct image_params *imgp __unused)
 1462 {
 1463         itimers_event_hook_exit(arg, p);
 1464 }
 1465 
 1466 /* Clean up timers when some process events are being triggered. */
 1467 static void
 1468 itimers_event_hook_exit(void *arg, struct proc *p)
 1469 {
 1470         struct itimers *its;
 1471         struct itimer *it;
 1472         int event = (int)(intptr_t)arg;
 1473         int i;
 1474 
 1475         if (p->p_itimers != NULL) {
 1476                 its = p->p_itimers;
 1477                 for (i = 0; i < MAX_CLOCKS; ++i) {
 1478                         if (posix_clocks[i].event_hook != NULL)
 1479                                 CLOCK_CALL(i, event_hook, (p, i, event));
 1480                 }
 1481                 /*
 1482                  * According to susv3, XSI interval timers should be inherited
 1483                  * by new image.
 1484                  */
 1485                 if (event == ITIMER_EV_EXEC)
 1486                         i = 3;
 1487                 else if (event == ITIMER_EV_EXIT)
 1488                         i = 0;
 1489                 else
 1490                         panic("unhandled event");
 1491                 for (; i < TIMER_MAX; ++i) {
 1492                         if ((it = its->its_timers[i]) != NULL)
 1493                                 kern_timer_delete(curthread, i);
 1494                 }
 1495                 if (its->its_timers[0] == NULL &&
 1496                     its->its_timers[1] == NULL &&
 1497                     its->its_timers[2] == NULL) {
 1498                         free(its, M_SUBPROC);
 1499                         p->p_itimers = NULL;
 1500                 }
 1501         }
 1502 }

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