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("$FreeBSD$");
   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 static void     no_lease_updatetime(int);
   78 
   79 static void     itimer_start(void);
   80 static int      itimer_init(void *, int, int);
   81 static void     itimer_fini(void *, int);
   82 static void     itimer_enter(struct itimer *);
   83 static void     itimer_leave(struct itimer *);
   84 static struct itimer *itimer_find(struct proc *, int);
   85 static void     itimers_alloc(struct proc *);
   86 static void     itimers_event_hook_exec(void *arg, struct proc *p, struct image_params *imgp);
   87 static void     itimers_event_hook_exit(void *arg, struct proc *p);
   88 static int      realtimer_create(struct itimer *);
   89 static int      realtimer_gettime(struct itimer *, struct itimerspec *);
   90 static int      realtimer_settime(struct itimer *, int,
   91                         struct itimerspec *, struct itimerspec *);
   92 static int      realtimer_delete(struct itimer *);
   93 static void     realtimer_clocktime(clockid_t, struct timespec *);
   94 static void     realtimer_expire(void *);
   95 static int      kern_timer_create(struct thread *, clockid_t,
   96                         struct sigevent *, int *, int);
   97 static int      kern_timer_delete(struct thread *, int);
   98 
   99 int             register_posix_clock(int, struct kclock *);
  100 void            itimer_fire(struct itimer *it);
  101 int             itimespecfix(struct timespec *ts);
  102 
  103 #define CLOCK_CALL(clock, call, arglist)                \
  104         ((*posix_clocks[clock].call) arglist)
  105 
  106 SYSINIT(posix_timer, SI_SUB_P1003_1B, SI_ORDER_FIRST+4, itimer_start, NULL);
  107 
  108 
  109 static void 
  110 no_lease_updatetime(deltat)
  111         int deltat;
  112 {
  113 }
  114 
  115 void (*lease_updatetime)(int)  = no_lease_updatetime;
  116 
  117 static int
  118 settime(struct thread *td, struct timeval *tv)
  119 {
  120         struct timeval delta, tv1, tv2;
  121         static struct timeval maxtime, laststep;
  122         struct timespec ts;
  123         int s;
  124 
  125         s = splclock();
  126         microtime(&tv1);
  127         delta = *tv;
  128         timevalsub(&delta, &tv1);
  129 
  130         /*
  131          * If the system is secure, we do not allow the time to be 
  132          * set to a value earlier than 1 second less than the highest
  133          * time we have yet seen. The worst a miscreant can do in
  134          * this circumstance is "freeze" time. He couldn't go
  135          * back to the past.
  136          *
  137          * We similarly do not allow the clock to be stepped more
  138          * than one second, nor more than once per second. This allows
  139          * a miscreant to make the clock march double-time, but no worse.
  140          */
  141         if (securelevel_gt(td->td_ucred, 1) != 0) {
  142                 if (delta.tv_sec < 0 || delta.tv_usec < 0) {
  143                         /*
  144                          * Update maxtime to latest time we've seen.
  145                          */
  146                         if (tv1.tv_sec > maxtime.tv_sec)
  147                                 maxtime = tv1;
  148                         tv2 = *tv;
  149                         timevalsub(&tv2, &maxtime);
  150                         if (tv2.tv_sec < -1) {
  151                                 tv->tv_sec = maxtime.tv_sec - 1;
  152                                 printf("Time adjustment clamped to -1 second\n");
  153                         }
  154                 } else {
  155                         if (tv1.tv_sec == laststep.tv_sec) {
  156                                 splx(s);
  157                                 return (EPERM);
  158                         }
  159                         if (delta.tv_sec > 1) {
  160                                 tv->tv_sec = tv1.tv_sec + 1;
  161                                 printf("Time adjustment clamped to +1 second\n");
  162                         }
  163                         laststep = *tv;
  164                 }
  165         }
  166 
  167         ts.tv_sec = tv->tv_sec;
  168         ts.tv_nsec = tv->tv_usec * 1000;
  169         mtx_lock(&Giant);
  170         tc_setclock(&ts);
  171         (void) splsoftclock();
  172         lease_updatetime(delta.tv_sec);
  173         splx(s);
  174         resettodr();
  175         mtx_unlock(&Giant);
  176         return (0);
  177 }
  178 
  179 #ifndef _SYS_SYSPROTO_H_
  180 struct clock_gettime_args {
  181         clockid_t clock_id;
  182         struct  timespec *tp;
  183 };
  184 #endif
  185 /* ARGSUSED */
  186 int
  187 clock_gettime(struct thread *td, struct clock_gettime_args *uap)
  188 {
  189         struct timespec ats;
  190         int error;
  191 
  192         error = kern_clock_gettime(td, uap->clock_id, &ats);
  193         if (error == 0)
  194                 error = copyout(&ats, uap->tp, sizeof(ats));
  195 
  196         return (error);
  197 }
  198 
  199 int
  200 kern_clock_gettime(struct thread *td, clockid_t clock_id, struct timespec *ats)
  201 {
  202         struct timeval sys, user;
  203         struct proc *p;
  204         uint64_t runtime, curtime, switchtime;
  205 
  206         p = td->td_proc;
  207         switch (clock_id) {
  208         case CLOCK_REALTIME:            /* Default to precise. */
  209         case CLOCK_REALTIME_PRECISE:
  210                 nanotime(ats);
  211                 break;
  212         case CLOCK_REALTIME_FAST:
  213                 getnanotime(ats);
  214                 break;
  215         case CLOCK_VIRTUAL:
  216                 PROC_LOCK(p);
  217                 PROC_SLOCK(p);
  218                 calcru(p, &user, &sys);
  219                 PROC_SUNLOCK(p);
  220                 PROC_UNLOCK(p);
  221                 TIMEVAL_TO_TIMESPEC(&user, ats);
  222                 break;
  223         case CLOCK_PROF:
  224                 PROC_LOCK(p);
  225                 PROC_SLOCK(p);
  226                 calcru(p, &user, &sys);
  227                 PROC_SUNLOCK(p);
  228                 PROC_UNLOCK(p);
  229                 timevaladd(&user, &sys);
  230                 TIMEVAL_TO_TIMESPEC(&user, ats);
  231                 break;
  232         case CLOCK_MONOTONIC:           /* Default to precise. */
  233         case CLOCK_MONOTONIC_PRECISE:
  234         case CLOCK_UPTIME:
  235         case CLOCK_UPTIME_PRECISE:
  236                 nanouptime(ats);
  237                 break;
  238         case CLOCK_UPTIME_FAST:
  239         case CLOCK_MONOTONIC_FAST:
  240                 getnanouptime(ats);
  241                 break;
  242         case CLOCK_SECOND:
  243                 ats->tv_sec = time_second;
  244                 ats->tv_nsec = 0;
  245                 break;
  246         case CLOCK_THREAD_CPUTIME_ID:
  247                 critical_enter();
  248                 switchtime = PCPU_GET(switchtime);
  249                 curtime = cpu_ticks();
  250                 runtime = td->td_runtime;
  251                 critical_exit();
  252                 runtime = cputick2usec(runtime + curtime - switchtime);
  253                 ats->tv_sec = runtime / 1000000;
  254                 ats->tv_nsec = runtime % 1000000 * 1000;
  255                 break;
  256         default:
  257                 return (EINVAL);
  258         }
  259         return (0);
  260 }
  261 
  262 #ifndef _SYS_SYSPROTO_H_
  263 struct clock_settime_args {
  264         clockid_t clock_id;
  265         const struct    timespec *tp;
  266 };
  267 #endif
  268 /* ARGSUSED */
  269 int
  270 clock_settime(struct thread *td, struct clock_settime_args *uap)
  271 {
  272         struct timespec ats;
  273         int error;
  274 
  275         if ((error = copyin(uap->tp, &ats, sizeof(ats))) != 0)
  276                 return (error);
  277         return (kern_clock_settime(td, uap->clock_id, &ats));
  278 }
  279 
  280 int
  281 kern_clock_settime(struct thread *td, clockid_t clock_id, struct timespec *ats)
  282 {
  283         struct timeval atv;
  284         int error;
  285 
  286         if ((error = priv_check(td, PRIV_CLOCK_SETTIME)) != 0)
  287                 return (error);
  288         if (clock_id != CLOCK_REALTIME)
  289                 return (EINVAL);
  290         if (ats->tv_nsec < 0 || ats->tv_nsec >= 1000000000)
  291                 return (EINVAL);
  292         /* XXX Don't convert nsec->usec and back */
  293         TIMESPEC_TO_TIMEVAL(&atv, ats);
  294         error = settime(td, &atv);
  295         return (error);
  296 }
  297 
  298 #ifndef _SYS_SYSPROTO_H_
  299 struct clock_getres_args {
  300         clockid_t clock_id;
  301         struct  timespec *tp;
  302 };
  303 #endif
  304 int
  305 clock_getres(struct thread *td, struct clock_getres_args *uap)
  306 {
  307         struct timespec ts;
  308         int error;
  309 
  310         if (uap->tp == NULL)
  311                 return (0);
  312 
  313         error = kern_clock_getres(td, uap->clock_id, &ts);
  314         if (error == 0)
  315                 error = copyout(&ts, uap->tp, sizeof(ts));
  316         return (error);
  317 }
  318 
  319 int
  320 kern_clock_getres(struct thread *td, clockid_t clock_id, struct timespec *ts)
  321 {
  322 
  323         ts->tv_sec = 0;
  324         switch (clock_id) {
  325         case CLOCK_REALTIME:
  326         case CLOCK_REALTIME_FAST:
  327         case CLOCK_REALTIME_PRECISE:
  328         case CLOCK_MONOTONIC:
  329         case CLOCK_MONOTONIC_FAST:
  330         case CLOCK_MONOTONIC_PRECISE:
  331         case CLOCK_UPTIME:
  332         case CLOCK_UPTIME_FAST:
  333         case CLOCK_UPTIME_PRECISE:
  334                 /*
  335                  * Round up the result of the division cheaply by adding 1.
  336                  * Rounding up is especially important if rounding down
  337                  * would give 0.  Perfect rounding is unimportant.
  338                  */
  339                 ts->tv_nsec = 1000000000 / tc_getfrequency() + 1;
  340                 break;
  341         case CLOCK_VIRTUAL:
  342         case CLOCK_PROF:
  343                 /* Accurately round up here because we can do so cheaply. */
  344                 ts->tv_nsec = (1000000000 + hz - 1) / hz;
  345                 break;
  346         case CLOCK_SECOND:
  347                 ts->tv_sec = 1;
  348                 ts->tv_nsec = 0;
  349                 break;
  350         default:
  351                 return (EINVAL);
  352         }
  353         return (0);
  354 }
  355 
  356 static int nanowait;
  357 
  358 int
  359 kern_nanosleep(struct thread *td, struct timespec *rqt, struct timespec *rmt)
  360 {
  361         struct timespec ts, ts2, ts3;
  362         struct timeval tv;
  363         int error;
  364 
  365         if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)
  366                 return (EINVAL);
  367         if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0))
  368                 return (0);
  369         getnanouptime(&ts);
  370         timespecadd(&ts, rqt);
  371         TIMESPEC_TO_TIMEVAL(&tv, rqt);
  372         for (;;) {
  373                 error = tsleep(&nanowait, PWAIT | PCATCH, "nanslp",
  374                     tvtohz(&tv));
  375                 getnanouptime(&ts2);
  376                 if (error != EWOULDBLOCK) {
  377                         if (error == ERESTART)
  378                                 error = EINTR;
  379                         if (rmt != NULL) {
  380                                 timespecsub(&ts, &ts2);
  381                                 if (ts.tv_sec < 0)
  382                                         timespecclear(&ts);
  383                                 *rmt = ts;
  384                         }
  385                         return (error);
  386                 }
  387                 if (timespeccmp(&ts2, &ts, >=))
  388                         return (0);
  389                 ts3 = ts;
  390                 timespecsub(&ts3, &ts2);
  391                 TIMESPEC_TO_TIMEVAL(&tv, &ts3);
  392         }
  393 }
  394 
  395 #ifndef _SYS_SYSPROTO_H_
  396 struct nanosleep_args {
  397         struct  timespec *rqtp;
  398         struct  timespec *rmtp;
  399 };
  400 #endif
  401 /* ARGSUSED */
  402 int
  403 nanosleep(struct thread *td, struct nanosleep_args *uap)
  404 {
  405         struct timespec rmt, rqt;
  406         int error;
  407 
  408         error = copyin(uap->rqtp, &rqt, sizeof(rqt));
  409         if (error)
  410                 return (error);
  411 
  412         if (uap->rmtp &&
  413             !useracc((caddr_t)uap->rmtp, sizeof(rmt), VM_PROT_WRITE))
  414                         return (EFAULT);
  415         error = kern_nanosleep(td, &rqt, &rmt);
  416         if (error && uap->rmtp) {
  417                 int error2;
  418 
  419                 error2 = copyout(&rmt, uap->rmtp, sizeof(rmt));
  420                 if (error2)
  421                         error = error2;
  422         }
  423         return (error);
  424 }
  425 
  426 #ifndef _SYS_SYSPROTO_H_
  427 struct gettimeofday_args {
  428         struct  timeval *tp;
  429         struct  timezone *tzp;
  430 };
  431 #endif
  432 /* ARGSUSED */
  433 int
  434 gettimeofday(struct thread *td, struct gettimeofday_args *uap)
  435 {
  436         struct timeval atv;
  437         struct timezone rtz;
  438         int error = 0;
  439 
  440         if (uap->tp) {
  441                 microtime(&atv);
  442                 error = copyout(&atv, uap->tp, sizeof (atv));
  443         }
  444         if (error == 0 && uap->tzp != NULL) {
  445                 rtz.tz_minuteswest = tz_minuteswest;
  446                 rtz.tz_dsttime = tz_dsttime;
  447                 error = copyout(&rtz, uap->tzp, sizeof (rtz));
  448         }
  449         return (error);
  450 }
  451 
  452 #ifndef _SYS_SYSPROTO_H_
  453 struct settimeofday_args {
  454         struct  timeval *tv;
  455         struct  timezone *tzp;
  456 };
  457 #endif
  458 /* ARGSUSED */
  459 int
  460 settimeofday(struct thread *td, struct settimeofday_args *uap)
  461 {
  462         struct timeval atv, *tvp;
  463         struct timezone atz, *tzp;
  464         int error;
  465 
  466         if (uap->tv) {
  467                 error = copyin(uap->tv, &atv, sizeof(atv));
  468                 if (error)
  469                         return (error);
  470                 tvp = &atv;
  471         } else
  472                 tvp = NULL;
  473         if (uap->tzp) {
  474                 error = copyin(uap->tzp, &atz, sizeof(atz));
  475                 if (error)
  476                         return (error);
  477                 tzp = &atz;
  478         } else
  479                 tzp = NULL;
  480         return (kern_settimeofday(td, tvp, tzp));
  481 }
  482 
  483 int
  484 kern_settimeofday(struct thread *td, struct timeval *tv, struct timezone *tzp)
  485 {
  486         int error;
  487 
  488         error = priv_check(td, PRIV_SETTIMEOFDAY);
  489         if (error)
  490                 return (error);
  491         /* Verify all parameters before changing time. */
  492         if (tv) {
  493                 if (tv->tv_usec < 0 || tv->tv_usec >= 1000000)
  494                         return (EINVAL);
  495                 error = settime(td, tv);
  496         }
  497         if (tzp && error == 0) {
  498                 tz_minuteswest = tzp->tz_minuteswest;
  499                 tz_dsttime = tzp->tz_dsttime;
  500         }
  501         return (error);
  502 }
  503 
  504 /*
  505  * Get value of an interval timer.  The process virtual and profiling virtual
  506  * time timers are kept in the p_stats area, since they can be swapped out.
  507  * These are kept internally in the way they are specified externally: in
  508  * time until they expire.
  509  *
  510  * The real time interval timer is kept in the process table slot for the
  511  * process, and its value (it_value) is kept as an absolute time rather than
  512  * as a delta, so that it is easy to keep periodic real-time signals from
  513  * drifting.
  514  *
  515  * Virtual time timers are processed in the hardclock() routine of
  516  * kern_clock.c.  The real time timer is processed by a timeout routine,
  517  * called from the softclock() routine.  Since a callout may be delayed in
  518  * real time due to interrupt processing in the system, it is possible for
  519  * the real time timeout routine (realitexpire, given below), to be delayed
  520  * in real time past when it is supposed to occur.  It does not suffice,
  521  * therefore, to reload the real timer .it_value from the real time timers
  522  * .it_interval.  Rather, we compute the next time in absolute time the timer
  523  * should go off.
  524  */
  525 #ifndef _SYS_SYSPROTO_H_
  526 struct getitimer_args {
  527         u_int   which;
  528         struct  itimerval *itv;
  529 };
  530 #endif
  531 int
  532 getitimer(struct thread *td, struct getitimer_args *uap)
  533 {
  534         struct itimerval aitv;
  535         int error;
  536 
  537         error = kern_getitimer(td, uap->which, &aitv);
  538         if (error != 0)
  539                 return (error);
  540         return (copyout(&aitv, uap->itv, sizeof (struct itimerval)));
  541 }
  542 
  543 int
  544 kern_getitimer(struct thread *td, u_int which, struct itimerval *aitv)
  545 {
  546         struct proc *p = td->td_proc;
  547         struct timeval ctv;
  548 
  549         if (which > ITIMER_PROF)
  550                 return (EINVAL);
  551 
  552         if (which == ITIMER_REAL) {
  553                 /*
  554                  * Convert from absolute to relative time in .it_value
  555                  * part of real time timer.  If time for real time timer
  556                  * has passed return 0, else return difference between
  557                  * current time and time for the timer to go off.
  558                  */
  559                 PROC_LOCK(p);
  560                 *aitv = p->p_realtimer;
  561                 PROC_UNLOCK(p);
  562                 if (timevalisset(&aitv->it_value)) {
  563                         getmicrouptime(&ctv);
  564                         if (timevalcmp(&aitv->it_value, &ctv, <))
  565                                 timevalclear(&aitv->it_value);
  566                         else
  567                                 timevalsub(&aitv->it_value, &ctv);
  568                 }
  569         } else {
  570                 PROC_SLOCK(p);
  571                 *aitv = p->p_stats->p_timer[which];
  572                 PROC_SUNLOCK(p);
  573         }
  574         return (0);
  575 }
  576 
  577 #ifndef _SYS_SYSPROTO_H_
  578 struct setitimer_args {
  579         u_int   which;
  580         struct  itimerval *itv, *oitv;
  581 };
  582 #endif
  583 int
  584 setitimer(struct thread *td, struct setitimer_args *uap)
  585 {
  586         struct itimerval aitv, oitv;
  587         int error;
  588 
  589         if (uap->itv == NULL) {
  590                 uap->itv = uap->oitv;
  591                 return (getitimer(td, (struct getitimer_args *)uap));
  592         }
  593 
  594         if ((error = copyin(uap->itv, &aitv, sizeof(struct itimerval))))
  595                 return (error);
  596         error = kern_setitimer(td, uap->which, &aitv, &oitv);
  597         if (error != 0 || uap->oitv == NULL)
  598                 return (error);
  599         return (copyout(&oitv, uap->oitv, sizeof(struct itimerval)));
  600 }
  601 
  602 int
  603 kern_setitimer(struct thread *td, u_int which, struct itimerval *aitv,
  604     struct itimerval *oitv)
  605 {
  606         struct proc *p = td->td_proc;
  607         struct timeval ctv;
  608 
  609         if (aitv == NULL)
  610                 return (kern_getitimer(td, which, oitv));
  611 
  612         if (which > ITIMER_PROF)
  613                 return (EINVAL);
  614         if (itimerfix(&aitv->it_value))
  615                 return (EINVAL);
  616         if (!timevalisset(&aitv->it_value))
  617                 timevalclear(&aitv->it_interval);
  618         else if (itimerfix(&aitv->it_interval))
  619                 return (EINVAL);
  620 
  621         if (which == ITIMER_REAL) {
  622                 PROC_LOCK(p);
  623                 if (timevalisset(&p->p_realtimer.it_value))
  624                         callout_stop(&p->p_itcallout);
  625                 getmicrouptime(&ctv);
  626                 if (timevalisset(&aitv->it_value)) {
  627                         callout_reset(&p->p_itcallout, tvtohz(&aitv->it_value),
  628                             realitexpire, p);
  629                         timevaladd(&aitv->it_value, &ctv);
  630                 }
  631                 *oitv = p->p_realtimer;
  632                 p->p_realtimer = *aitv;
  633                 PROC_UNLOCK(p);
  634                 if (timevalisset(&oitv->it_value)) {
  635                         if (timevalcmp(&oitv->it_value, &ctv, <))
  636                                 timevalclear(&oitv->it_value);
  637                         else
  638                                 timevalsub(&oitv->it_value, &ctv);
  639                 }
  640         } else {
  641                 PROC_SLOCK(p);
  642                 *oitv = p->p_stats->p_timer[which];
  643                 p->p_stats->p_timer[which] = *aitv;
  644                 PROC_SUNLOCK(p);
  645         }
  646         return (0);
  647 }
  648 
  649 /*
  650  * Real interval timer expired:
  651  * send process whose timer expired an alarm signal.
  652  * If time is not set up to reload, then just return.
  653  * Else compute next time timer should go off which is > current time.
  654  * This is where delay in processing this timeout causes multiple
  655  * SIGALRM calls to be compressed into one.
  656  * tvtohz() always adds 1 to allow for the time until the next clock
  657  * interrupt being strictly less than 1 clock tick, but we don't want
  658  * that here since we want to appear to be in sync with the clock
  659  * interrupt even when we're delayed.
  660  */
  661 void
  662 realitexpire(void *arg)
  663 {
  664         struct proc *p;
  665         struct timeval ctv, ntv;
  666 
  667         p = (struct proc *)arg;
  668         PROC_LOCK(p);
  669         psignal(p, SIGALRM);
  670         if (!timevalisset(&p->p_realtimer.it_interval)) {
  671                 timevalclear(&p->p_realtimer.it_value);
  672                 if (p->p_flag & P_WEXIT)
  673                         wakeup(&p->p_itcallout);
  674                 PROC_UNLOCK(p);
  675                 return;
  676         }
  677         for (;;) {
  678                 timevaladd(&p->p_realtimer.it_value,
  679                     &p->p_realtimer.it_interval);
  680                 getmicrouptime(&ctv);
  681                 if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) {
  682                         ntv = p->p_realtimer.it_value;
  683                         timevalsub(&ntv, &ctv);
  684                         callout_reset(&p->p_itcallout, tvtohz(&ntv) - 1,
  685                             realitexpire, p);
  686                         PROC_UNLOCK(p);
  687                         return;
  688                 }
  689         }
  690         /*NOTREACHED*/
  691 }
  692 
  693 /*
  694  * Check that a proposed value to load into the .it_value or
  695  * .it_interval part of an interval timer is acceptable, and
  696  * fix it to have at least minimal value (i.e. if it is less
  697  * than the resolution of the clock, round it up.)
  698  */
  699 int
  700 itimerfix(struct timeval *tv)
  701 {
  702 
  703         if (tv->tv_sec < 0 || tv->tv_usec < 0 || tv->tv_usec >= 1000000)
  704                 return (EINVAL);
  705         if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)
  706                 tv->tv_usec = tick;
  707         return (0);
  708 }
  709 
  710 /*
  711  * Decrement an interval timer by a specified number
  712  * of microseconds, which must be less than a second,
  713  * i.e. < 1000000.  If the timer expires, then reload
  714  * it.  In this case, carry over (usec - old value) to
  715  * reduce the value reloaded into the timer so that
  716  * the timer does not drift.  This routine assumes
  717  * that it is called in a context where the timers
  718  * on which it is operating cannot change in value.
  719  */
  720 int
  721 itimerdecr(struct itimerval *itp, int usec)
  722 {
  723 
  724         if (itp->it_value.tv_usec < usec) {
  725                 if (itp->it_value.tv_sec == 0) {
  726                         /* expired, and already in next interval */
  727                         usec -= itp->it_value.tv_usec;
  728                         goto expire;
  729                 }
  730                 itp->it_value.tv_usec += 1000000;
  731                 itp->it_value.tv_sec--;
  732         }
  733         itp->it_value.tv_usec -= usec;
  734         usec = 0;
  735         if (timevalisset(&itp->it_value))
  736                 return (1);
  737         /* expired, exactly at end of interval */
  738 expire:
  739         if (timevalisset(&itp->it_interval)) {
  740                 itp->it_value = itp->it_interval;
  741                 itp->it_value.tv_usec -= usec;
  742                 if (itp->it_value.tv_usec < 0) {
  743                         itp->it_value.tv_usec += 1000000;
  744                         itp->it_value.tv_sec--;
  745                 }
  746         } else
  747                 itp->it_value.tv_usec = 0;              /* sec is already 0 */
  748         return (0);
  749 }
  750 
  751 /*
  752  * Add and subtract routines for timevals.
  753  * N.B.: subtract routine doesn't deal with
  754  * results which are before the beginning,
  755  * it just gets very confused in this case.
  756  * Caveat emptor.
  757  */
  758 void
  759 timevaladd(struct timeval *t1, const struct timeval *t2)
  760 {
  761 
  762         t1->tv_sec += t2->tv_sec;
  763         t1->tv_usec += t2->tv_usec;
  764         timevalfix(t1);
  765 }
  766 
  767 void
  768 timevalsub(struct timeval *t1, const struct timeval *t2)
  769 {
  770 
  771         t1->tv_sec -= t2->tv_sec;
  772         t1->tv_usec -= t2->tv_usec;
  773         timevalfix(t1);
  774 }
  775 
  776 static void
  777 timevalfix(struct timeval *t1)
  778 {
  779 
  780         if (t1->tv_usec < 0) {
  781                 t1->tv_sec--;
  782                 t1->tv_usec += 1000000;
  783         }
  784         if (t1->tv_usec >= 1000000) {
  785                 t1->tv_sec++;
  786                 t1->tv_usec -= 1000000;
  787         }
  788 }
  789 
  790 /*
  791  * ratecheck(): simple time-based rate-limit checking.
  792  */
  793 int
  794 ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
  795 {
  796         struct timeval tv, delta;
  797         int rv = 0;
  798 
  799         getmicrouptime(&tv);            /* NB: 10ms precision */
  800         delta = tv;
  801         timevalsub(&delta, lasttime);
  802 
  803         /*
  804          * check for 0,0 is so that the message will be seen at least once,
  805          * even if interval is huge.
  806          */
  807         if (timevalcmp(&delta, mininterval, >=) ||
  808             (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
  809                 *lasttime = tv;
  810                 rv = 1;
  811         }
  812 
  813         return (rv);
  814 }
  815 
  816 /*
  817  * ppsratecheck(): packets (or events) per second limitation.
  818  *
  819  * Return 0 if the limit is to be enforced (e.g. the caller
  820  * should drop a packet because of the rate limitation).
  821  *
  822  * maxpps of 0 always causes zero to be returned.  maxpps of -1
  823  * always causes 1 to be returned; this effectively defeats rate
  824  * limiting.
  825  *
  826  * Note that we maintain the struct timeval for compatibility
  827  * with other bsd systems.  We reuse the storage and just monitor
  828  * clock ticks for minimal overhead.  
  829  */
  830 int
  831 ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
  832 {
  833         int now;
  834 
  835         /*
  836          * Reset the last time and counter if this is the first call
  837          * or more than a second has passed since the last update of
  838          * lasttime.
  839          */
  840         now = ticks;
  841         if (lasttime->tv_sec == 0 || (u_int)(now - lasttime->tv_sec) >= hz) {
  842                 lasttime->tv_sec = now;
  843                 *curpps = 1;
  844                 return (maxpps != 0);
  845         } else {
  846                 (*curpps)++;            /* NB: ignore potential overflow */
  847                 return (maxpps < 0 || *curpps < maxpps);
  848         }
  849 }
  850 
  851 static void
  852 itimer_start(void)
  853 {
  854         struct kclock rt_clock = {
  855                 .timer_create  = realtimer_create,
  856                 .timer_delete  = realtimer_delete,
  857                 .timer_settime = realtimer_settime,
  858                 .timer_gettime = realtimer_gettime,
  859                 .event_hook    = NULL
  860         };
  861 
  862         itimer_zone = uma_zcreate("itimer", sizeof(struct itimer),
  863                 NULL, NULL, itimer_init, itimer_fini, UMA_ALIGN_PTR, 0);
  864         register_posix_clock(CLOCK_REALTIME,  &rt_clock);
  865         register_posix_clock(CLOCK_MONOTONIC, &rt_clock);
  866         p31b_setcfg(CTL_P1003_1B_TIMERS, 200112L);
  867         p31b_setcfg(CTL_P1003_1B_DELAYTIMER_MAX, INT_MAX);
  868         p31b_setcfg(CTL_P1003_1B_TIMER_MAX, TIMER_MAX);
  869         EVENTHANDLER_REGISTER(process_exit, itimers_event_hook_exit,
  870                 (void *)ITIMER_EV_EXIT, EVENTHANDLER_PRI_ANY);
  871         EVENTHANDLER_REGISTER(process_exec, itimers_event_hook_exec,
  872                 (void *)ITIMER_EV_EXEC, EVENTHANDLER_PRI_ANY);
  873 }
  874 
  875 int
  876 register_posix_clock(int clockid, struct kclock *clk)
  877 {
  878         if ((unsigned)clockid >= MAX_CLOCKS) {
  879                 printf("%s: invalid clockid\n", __func__);
  880                 return (0);
  881         }
  882         posix_clocks[clockid] = *clk;
  883         return (1);
  884 }
  885 
  886 static int
  887 itimer_init(void *mem, int size, int flags)
  888 {
  889         struct itimer *it;
  890 
  891         it = (struct itimer *)mem;
  892         mtx_init(&it->it_mtx, "itimer lock", NULL, MTX_DEF);
  893         return (0);
  894 }
  895 
  896 static void
  897 itimer_fini(void *mem, int size)
  898 {
  899         struct itimer *it;
  900 
  901         it = (struct itimer *)mem;
  902         mtx_destroy(&it->it_mtx);
  903 }
  904 
  905 static void
  906 itimer_enter(struct itimer *it)
  907 {
  908 
  909         mtx_assert(&it->it_mtx, MA_OWNED);
  910         it->it_usecount++;
  911 }
  912 
  913 static void
  914 itimer_leave(struct itimer *it)
  915 {
  916 
  917         mtx_assert(&it->it_mtx, MA_OWNED);
  918         KASSERT(it->it_usecount > 0, ("invalid it_usecount"));
  919 
  920         if (--it->it_usecount == 0 && (it->it_flags & ITF_WANTED) != 0)
  921                 wakeup(it);
  922 }
  923 
  924 #ifndef _SYS_SYSPROTO_H_
  925 struct ktimer_create_args {
  926         clockid_t clock_id;
  927         struct sigevent * evp;
  928         int * timerid;
  929 };
  930 #endif
  931 int
  932 ktimer_create(struct thread *td, struct ktimer_create_args *uap)
  933 {
  934         struct sigevent *evp1, ev;
  935         int id;
  936         int error;
  937 
  938         if (uap->evp != NULL) {
  939                 error = copyin(uap->evp, &ev, sizeof(ev));
  940                 if (error != 0)
  941                         return (error);
  942                 evp1 = &ev;
  943         } else
  944                 evp1 = NULL;
  945 
  946         error = kern_timer_create(td, uap->clock_id, evp1, &id, -1);
  947 
  948         if (error == 0) {
  949                 error = copyout(&id, uap->timerid, sizeof(int));
  950                 if (error != 0)
  951                         kern_timer_delete(td, id);
  952         }
  953         return (error);
  954 }
  955 
  956 static int
  957 kern_timer_create(struct thread *td, clockid_t clock_id,
  958         struct sigevent *evp, int *timerid, int preset_id)
  959 {
  960         struct proc *p = td->td_proc;
  961         struct itimer *it;
  962         int id;
  963         int error;
  964 
  965         if (clock_id < 0 || clock_id >= MAX_CLOCKS)
  966                 return (EINVAL);
  967 
  968         if (posix_clocks[clock_id].timer_create == NULL)
  969                 return (EINVAL);
  970 
  971         if (evp != NULL) {
  972                 if (evp->sigev_notify != SIGEV_NONE &&
  973                     evp->sigev_notify != SIGEV_SIGNAL &&
  974                     evp->sigev_notify != SIGEV_THREAD_ID)
  975                         return (EINVAL);
  976                 if ((evp->sigev_notify == SIGEV_SIGNAL ||
  977                      evp->sigev_notify == SIGEV_THREAD_ID) &&
  978                         !_SIG_VALID(evp->sigev_signo))
  979                         return (EINVAL);
  980         }
  981         
  982         if (p->p_itimers == NULL)
  983                 itimers_alloc(p);
  984         
  985         it = uma_zalloc(itimer_zone, M_WAITOK);
  986         it->it_flags = 0;
  987         it->it_usecount = 0;
  988         it->it_active = 0;
  989         timespecclear(&it->it_time.it_value);
  990         timespecclear(&it->it_time.it_interval);
  991         it->it_overrun = 0;
  992         it->it_overrun_last = 0;
  993         it->it_clockid = clock_id;
  994         it->it_timerid = -1;
  995         it->it_proc = p;
  996         ksiginfo_init(&it->it_ksi);
  997         it->it_ksi.ksi_flags |= KSI_INS | KSI_EXT;
  998         error = CLOCK_CALL(clock_id, timer_create, (it));
  999         if (error != 0)
 1000                 goto out;
 1001 
 1002         PROC_LOCK(p);
 1003         if (preset_id != -1) {
 1004                 KASSERT(preset_id >= 0 && preset_id < 3, ("invalid preset_id"));
 1005                 id = preset_id;
 1006                 if (p->p_itimers->its_timers[id] != NULL) {
 1007                         PROC_UNLOCK(p);
 1008                         error = 0;
 1009                         goto out;
 1010                 }
 1011         } else {
 1012                 /*
 1013                  * Find a free timer slot, skipping those reserved
 1014                  * for setitimer().
 1015                  */
 1016                 for (id = 3; id < TIMER_MAX; id++)
 1017                         if (p->p_itimers->its_timers[id] == NULL)
 1018                                 break;
 1019                 if (id == TIMER_MAX) {
 1020                         PROC_UNLOCK(p);
 1021                         error = EAGAIN;
 1022                         goto out;
 1023                 }
 1024         }
 1025         it->it_timerid = id;
 1026         p->p_itimers->its_timers[id] = it;
 1027         if (evp != NULL)
 1028                 it->it_sigev = *evp;
 1029         else {
 1030                 it->it_sigev.sigev_notify = SIGEV_SIGNAL;
 1031                 switch (clock_id) {
 1032                 default:
 1033                 case CLOCK_REALTIME:
 1034                         it->it_sigev.sigev_signo = SIGALRM;
 1035                         break;
 1036                 case CLOCK_VIRTUAL:
 1037                         it->it_sigev.sigev_signo = SIGVTALRM;
 1038                         break;
 1039                 case CLOCK_PROF:
 1040                         it->it_sigev.sigev_signo = SIGPROF;
 1041                         break;
 1042                 }
 1043                 it->it_sigev.sigev_value.sival_int = id;
 1044         }
 1045 
 1046         if (it->it_sigev.sigev_notify == SIGEV_SIGNAL ||
 1047             it->it_sigev.sigev_notify == SIGEV_THREAD_ID) {
 1048                 it->it_ksi.ksi_signo = it->it_sigev.sigev_signo;
 1049                 it->it_ksi.ksi_code = SI_TIMER;
 1050                 it->it_ksi.ksi_value = it->it_sigev.sigev_value;
 1051                 it->it_ksi.ksi_timerid = id;
 1052         }
 1053         PROC_UNLOCK(p);
 1054         *timerid = id;
 1055         return (0);
 1056 
 1057 out:
 1058         ITIMER_LOCK(it);
 1059         CLOCK_CALL(it->it_clockid, timer_delete, (it));
 1060         ITIMER_UNLOCK(it);
 1061         uma_zfree(itimer_zone, it);
 1062         return (error);
 1063 }
 1064 
 1065 #ifndef _SYS_SYSPROTO_H_
 1066 struct ktimer_delete_args {
 1067         int timerid;
 1068 };
 1069 #endif
 1070 int
 1071 ktimer_delete(struct thread *td, struct ktimer_delete_args *uap)
 1072 {
 1073         return (kern_timer_delete(td, uap->timerid));
 1074 }
 1075 
 1076 static struct itimer *
 1077 itimer_find(struct proc *p, int timerid)
 1078 {
 1079         struct itimer *it;
 1080 
 1081         PROC_LOCK_ASSERT(p, MA_OWNED);
 1082         if ((p->p_itimers == NULL) ||
 1083             (timerid < 0) || (timerid >= TIMER_MAX) ||
 1084             (it = p->p_itimers->its_timers[timerid]) == NULL) {
 1085                 return (NULL);
 1086         }
 1087         ITIMER_LOCK(it);
 1088         if ((it->it_flags & ITF_DELETING) != 0) {
 1089                 ITIMER_UNLOCK(it);
 1090                 it = NULL;
 1091         }
 1092         return (it);
 1093 }
 1094 
 1095 static int
 1096 kern_timer_delete(struct thread *td, int timerid)
 1097 {
 1098         struct proc *p = td->td_proc;
 1099         struct itimer *it;
 1100 
 1101         PROC_LOCK(p);
 1102         it = itimer_find(p, timerid);
 1103         if (it == NULL) {
 1104                 PROC_UNLOCK(p);
 1105                 return (EINVAL);
 1106         }
 1107         PROC_UNLOCK(p);
 1108 
 1109         it->it_flags |= ITF_DELETING;
 1110         while (it->it_usecount > 0) {
 1111                 it->it_flags |= ITF_WANTED;
 1112                 msleep(it, &it->it_mtx, PPAUSE, "itimer", 0);
 1113         }
 1114         it->it_flags &= ~ITF_WANTED;
 1115         CLOCK_CALL(it->it_clockid, timer_delete, (it));
 1116         ITIMER_UNLOCK(it);
 1117 
 1118         PROC_LOCK(p);
 1119         if (KSI_ONQ(&it->it_ksi))
 1120                 sigqueue_take(&it->it_ksi);
 1121         p->p_itimers->its_timers[timerid] = NULL;
 1122         PROC_UNLOCK(p);
 1123         uma_zfree(itimer_zone, it);
 1124         return (0);
 1125 }
 1126 
 1127 #ifndef _SYS_SYSPROTO_H_
 1128 struct ktimer_settime_args {
 1129         int timerid;
 1130         int flags;
 1131         const struct itimerspec * value;
 1132         struct itimerspec * ovalue;
 1133 };
 1134 #endif
 1135 int
 1136 ktimer_settime(struct thread *td, struct ktimer_settime_args *uap)
 1137 {
 1138         struct proc *p = td->td_proc;
 1139         struct itimer *it;
 1140         struct itimerspec val, oval, *ovalp;
 1141         int error;
 1142 
 1143         error = copyin(uap->value, &val, sizeof(val));
 1144         if (error != 0)
 1145                 return (error);
 1146         
 1147         if (uap->ovalue != NULL)
 1148                 ovalp = &oval;
 1149         else
 1150                 ovalp = NULL;
 1151 
 1152         PROC_LOCK(p);
 1153         if (uap->timerid < 3 ||
 1154             (it = itimer_find(p, uap->timerid)) == NULL) {
 1155                 PROC_UNLOCK(p);
 1156                 error = EINVAL;
 1157         } else {
 1158                 PROC_UNLOCK(p);
 1159                 itimer_enter(it);
 1160                 error = CLOCK_CALL(it->it_clockid, timer_settime,
 1161                                 (it, uap->flags, &val, ovalp));
 1162                 itimer_leave(it);
 1163                 ITIMER_UNLOCK(it);
 1164         }
 1165         if (error == 0 && uap->ovalue != NULL)
 1166                 error = copyout(ovalp, uap->ovalue, sizeof(*ovalp));
 1167         return (error);
 1168 }
 1169 
 1170 #ifndef _SYS_SYSPROTO_H_
 1171 struct ktimer_gettime_args {
 1172         int timerid;
 1173         struct itimerspec * value;
 1174 };
 1175 #endif
 1176 int
 1177 ktimer_gettime(struct thread *td, struct ktimer_gettime_args *uap)
 1178 {
 1179         struct proc *p = td->td_proc;
 1180         struct itimer *it;
 1181         struct itimerspec val;
 1182         int error;
 1183 
 1184         PROC_LOCK(p);
 1185         if (uap->timerid < 3 ||
 1186            (it = itimer_find(p, uap->timerid)) == NULL) {
 1187                 PROC_UNLOCK(p);
 1188                 error = EINVAL;
 1189         } else {
 1190                 PROC_UNLOCK(p);
 1191                 itimer_enter(it);
 1192                 error = CLOCK_CALL(it->it_clockid, timer_gettime,
 1193                                 (it, &val));
 1194                 itimer_leave(it);
 1195                 ITIMER_UNLOCK(it);
 1196         }
 1197         if (error == 0)
 1198                 error = copyout(&val, uap->value, sizeof(val));
 1199         return (error);
 1200 }
 1201 
 1202 #ifndef _SYS_SYSPROTO_H_
 1203 struct timer_getoverrun_args {
 1204         int timerid;
 1205 };
 1206 #endif
 1207 int
 1208 ktimer_getoverrun(struct thread *td, struct ktimer_getoverrun_args *uap)
 1209 {
 1210         struct proc *p = td->td_proc;
 1211         struct itimer *it;
 1212         int error ;
 1213 
 1214         PROC_LOCK(p);
 1215         if (uap->timerid < 3 ||
 1216             (it = itimer_find(p, uap->timerid)) == NULL) {
 1217                 PROC_UNLOCK(p);
 1218                 error = EINVAL;
 1219         } else {
 1220                 td->td_retval[0] = it->it_overrun_last;
 1221                 ITIMER_UNLOCK(it);
 1222                 PROC_UNLOCK(p);
 1223                 error = 0;
 1224         }
 1225         return (error);
 1226 }
 1227 
 1228 static int
 1229 realtimer_create(struct itimer *it)
 1230 {
 1231         callout_init_mtx(&it->it_callout, &it->it_mtx, 0);
 1232         return (0);
 1233 }
 1234 
 1235 static int
 1236 realtimer_delete(struct itimer *it)
 1237 {
 1238         mtx_assert(&it->it_mtx, MA_OWNED);
 1239         
 1240         /*
 1241          * clear timer's value and interval to tell realtimer_expire
 1242          * to not rearm the timer.
 1243          */
 1244         timespecclear(&it->it_time.it_value);
 1245         timespecclear(&it->it_time.it_interval);
 1246         ITIMER_UNLOCK(it);
 1247         callout_drain(&it->it_callout);
 1248         ITIMER_LOCK(it);
 1249         return (0);
 1250 }
 1251 
 1252 static int
 1253 realtimer_gettime(struct itimer *it, struct itimerspec *ovalue)
 1254 {
 1255         struct timespec cts;
 1256 
 1257         mtx_assert(&it->it_mtx, MA_OWNED);
 1258 
 1259         realtimer_clocktime(it->it_clockid, &cts);
 1260         *ovalue = it->it_time;
 1261         if (ovalue->it_value.tv_sec != 0 || ovalue->it_value.tv_nsec != 0) {
 1262                 timespecsub(&ovalue->it_value, &cts);
 1263                 if (ovalue->it_value.tv_sec < 0 ||
 1264                     (ovalue->it_value.tv_sec == 0 &&
 1265                      ovalue->it_value.tv_nsec == 0)) {
 1266                         ovalue->it_value.tv_sec  = 0;
 1267                         ovalue->it_value.tv_nsec = 1;
 1268                 }
 1269         }
 1270         return (0);
 1271 }
 1272 
 1273 static int
 1274 realtimer_settime(struct itimer *it, int flags,
 1275         struct itimerspec *value, struct itimerspec *ovalue)
 1276 {
 1277         struct timespec cts, ts;
 1278         struct timeval tv;
 1279         struct itimerspec val;
 1280 
 1281         mtx_assert(&it->it_mtx, MA_OWNED);
 1282 
 1283         val = *value;
 1284         if (itimespecfix(&val.it_value))
 1285                 return (EINVAL);
 1286 
 1287         if (timespecisset(&val.it_value)) {
 1288                 if (itimespecfix(&val.it_interval))
 1289                         return (EINVAL);
 1290         } else {
 1291                 timespecclear(&val.it_interval);
 1292         }
 1293         
 1294         if (ovalue != NULL)
 1295                 realtimer_gettime(it, ovalue);
 1296 
 1297         it->it_time = val;
 1298         if (timespecisset(&val.it_value)) {
 1299                 realtimer_clocktime(it->it_clockid, &cts);
 1300                 ts = val.it_value;
 1301                 if ((flags & TIMER_ABSTIME) == 0) {
 1302                         /* Convert to absolute time. */
 1303                         timespecadd(&it->it_time.it_value, &cts);
 1304                 } else {
 1305                         timespecsub(&ts, &cts);
 1306                         /*
 1307                          * We don't care if ts is negative, tztohz will
 1308                          * fix it.
 1309                          */
 1310                 }
 1311                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
 1312                 callout_reset(&it->it_callout, tvtohz(&tv),
 1313                         realtimer_expire, it);
 1314         } else {
 1315                 callout_stop(&it->it_callout);
 1316         }
 1317 
 1318         return (0);
 1319 }
 1320 
 1321 static void
 1322 realtimer_clocktime(clockid_t id, struct timespec *ts)
 1323 {
 1324         if (id == CLOCK_REALTIME)
 1325                 getnanotime(ts);
 1326         else    /* CLOCK_MONOTONIC */
 1327                 getnanouptime(ts);
 1328 }
 1329 
 1330 int
 1331 itimer_accept(struct proc *p, int timerid, ksiginfo_t *ksi)
 1332 {
 1333         struct itimer *it;
 1334 
 1335         PROC_LOCK_ASSERT(p, MA_OWNED);
 1336         it = itimer_find(p, timerid);
 1337         if (it != NULL) {
 1338                 ksi->ksi_overrun = it->it_overrun;
 1339                 it->it_overrun_last = it->it_overrun;
 1340                 it->it_overrun = 0;
 1341                 ITIMER_UNLOCK(it);
 1342                 return (0);
 1343         }
 1344         return (EINVAL);
 1345 }
 1346 
 1347 int
 1348 itimespecfix(struct timespec *ts)
 1349 {
 1350 
 1351         if (ts->tv_sec < 0 || ts->tv_nsec < 0 || ts->tv_nsec >= 1000000000)
 1352                 return (EINVAL);
 1353         if (ts->tv_sec == 0 && ts->tv_nsec != 0 && ts->tv_nsec < tick * 1000)
 1354                 ts->tv_nsec = tick * 1000;
 1355         return (0);
 1356 }
 1357 
 1358 /* Timeout callback for realtime timer */
 1359 static void
 1360 realtimer_expire(void *arg)
 1361 {
 1362         struct timespec cts, ts;
 1363         struct timeval tv;
 1364         struct itimer *it;
 1365         struct proc *p;
 1366 
 1367         it = (struct itimer *)arg;
 1368         p = it->it_proc;
 1369 
 1370         realtimer_clocktime(it->it_clockid, &cts);
 1371         /* Only fire if time is reached. */
 1372         if (timespeccmp(&cts, &it->it_time.it_value, >=)) {
 1373                 if (timespecisset(&it->it_time.it_interval)) {
 1374                         timespecadd(&it->it_time.it_value,
 1375                                     &it->it_time.it_interval);
 1376                         while (timespeccmp(&cts, &it->it_time.it_value, >=)) {
 1377                                 if (it->it_overrun < INT_MAX)
 1378                                         it->it_overrun++;
 1379                                 else
 1380                                         it->it_ksi.ksi_errno = ERANGE;
 1381                                 timespecadd(&it->it_time.it_value,
 1382                                             &it->it_time.it_interval);
 1383                         }
 1384                 } else {
 1385                         /* single shot timer ? */
 1386                         timespecclear(&it->it_time.it_value);
 1387                 }
 1388                 if (timespecisset(&it->it_time.it_value)) {
 1389                         ts = it->it_time.it_value;
 1390                         timespecsub(&ts, &cts);
 1391                         TIMESPEC_TO_TIMEVAL(&tv, &ts);
 1392                         callout_reset(&it->it_callout, tvtohz(&tv),
 1393                                  realtimer_expire, it);
 1394                 }
 1395                 itimer_enter(it);
 1396                 ITIMER_UNLOCK(it);
 1397                 itimer_fire(it);
 1398                 ITIMER_LOCK(it);
 1399                 itimer_leave(it);
 1400         } else if (timespecisset(&it->it_time.it_value)) {
 1401                 ts = it->it_time.it_value;
 1402                 timespecsub(&ts, &cts);
 1403                 TIMESPEC_TO_TIMEVAL(&tv, &ts);
 1404                 callout_reset(&it->it_callout, tvtohz(&tv), realtimer_expire,
 1405                         it);
 1406         }
 1407 }
 1408 
 1409 void
 1410 itimer_fire(struct itimer *it)
 1411 {
 1412         struct proc *p = it->it_proc;
 1413         int ret;
 1414 
 1415         if (it->it_sigev.sigev_notify == SIGEV_SIGNAL ||
 1416             it->it_sigev.sigev_notify == SIGEV_THREAD_ID) {
 1417                 PROC_LOCK(p);
 1418                 if (!KSI_ONQ(&it->it_ksi)) {
 1419                         it->it_ksi.ksi_errno = 0;
 1420                         ret = psignal_event(p, &it->it_sigev, &it->it_ksi);
 1421                         if (__predict_false(ret != 0)) {
 1422                                 it->it_overrun++;
 1423                                 /*
 1424                                  * Broken userland code, thread went
 1425                                  * away, disarm the timer.
 1426                                  */
 1427                                 if (ret == ESRCH) {
 1428                                         ITIMER_LOCK(it);
 1429                                         timespecclear(&it->it_time.it_value);
 1430                                         timespecclear(&it->it_time.it_interval);
 1431                                         callout_stop(&it->it_callout);
 1432                                         ITIMER_UNLOCK(it);
 1433                                 }
 1434                         }
 1435                 } else {
 1436                         if (it->it_overrun < INT_MAX)
 1437                                 it->it_overrun++;
 1438                         else
 1439                                 it->it_ksi.ksi_errno = ERANGE;
 1440                 }
 1441                 PROC_UNLOCK(p);
 1442         }
 1443 }
 1444 
 1445 static void
 1446 itimers_alloc(struct proc *p)
 1447 {
 1448         struct itimers *its;
 1449         int i;
 1450 
 1451         its = malloc(sizeof (struct itimers), M_SUBPROC, M_WAITOK | M_ZERO);
 1452         LIST_INIT(&its->its_virtual);
 1453         LIST_INIT(&its->its_prof);
 1454         TAILQ_INIT(&its->its_worklist);
 1455         for (i = 0; i < TIMER_MAX; i++)
 1456                 its->its_timers[i] = NULL;
 1457         PROC_LOCK(p);
 1458         if (p->p_itimers == NULL) {
 1459                 p->p_itimers = its;
 1460                 PROC_UNLOCK(p);
 1461         }
 1462         else {
 1463                 PROC_UNLOCK(p);
 1464                 free(its, M_SUBPROC);
 1465         }
 1466 }
 1467 
 1468 static void
 1469 itimers_event_hook_exec(void *arg, struct proc *p, struct image_params *imgp __unused)
 1470 {
 1471         itimers_event_hook_exit(arg, p);
 1472 }
 1473 
 1474 /* Clean up timers when some process events are being triggered. */
 1475 static void
 1476 itimers_event_hook_exit(void *arg, struct proc *p)
 1477 {
 1478         struct itimers *its;
 1479         struct itimer *it;
 1480         int event = (int)(intptr_t)arg;
 1481         int i;
 1482 
 1483         if (p->p_itimers != NULL) {
 1484                 its = p->p_itimers;
 1485                 for (i = 0; i < MAX_CLOCKS; ++i) {
 1486                         if (posix_clocks[i].event_hook != NULL)
 1487                                 CLOCK_CALL(i, event_hook, (p, i, event));
 1488                 }
 1489                 /*
 1490                  * According to susv3, XSI interval timers should be inherited
 1491                  * by new image.
 1492                  */
 1493                 if (event == ITIMER_EV_EXEC)
 1494                         i = 3;
 1495                 else if (event == ITIMER_EV_EXIT)
 1496                         i = 0;
 1497                 else
 1498                         panic("unhandled event");
 1499                 for (; i < TIMER_MAX; ++i) {
 1500                         if ((it = its->its_timers[i]) != NULL)
 1501                                 kern_timer_delete(curthread, i);
 1502                 }
 1503                 if (its->its_timers[0] == NULL &&
 1504                     its->its_timers[1] == NULL &&
 1505                     its->its_timers[2] == NULL) {
 1506                         free(its, M_SUBPROC);
 1507                         p->p_itimers = NULL;
 1508                 }
 1509         }
 1510 }
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FreeBSD/Linux Kernel Cross Reference sys/kern/kern_time.c

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