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kern_time.c revision 1.146
      1 /*	$NetBSD: kern_time.c,v 1.146 2008/04/28 20:24:03 martin Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2000, 2004, 2005, 2007, 2008 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christopher G. Demetriou.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * Copyright (c) 1982, 1986, 1989, 1993
     34  *	The Regents of the University of California.  All rights reserved.
     35  *
     36  * Redistribution and use in source and binary forms, with or without
     37  * modification, are permitted provided that the following conditions
     38  * are met:
     39  * 1. Redistributions of source code must retain the above copyright
     40  *    notice, this list of conditions and the following disclaimer.
     41  * 2. Redistributions in binary form must reproduce the above copyright
     42  *    notice, this list of conditions and the following disclaimer in the
     43  *    documentation and/or other materials provided with the distribution.
     44  * 3. Neither the name of the University nor the names of its contributors
     45  *    may be used to endorse or promote products derived from this software
     46  *    without specific prior written permission.
     47  *
     48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     58  * SUCH DAMAGE.
     59  *
     60  *	@(#)kern_time.c	8.4 (Berkeley) 5/26/95
     61  */
     62 
     63 #include <sys/cdefs.h>
     64 __KERNEL_RCSID(0, "$NetBSD: kern_time.c,v 1.146 2008/04/28 20:24:03 martin Exp $");
     65 
     66 #include <sys/param.h>
     67 #include <sys/resourcevar.h>
     68 #include <sys/kernel.h>
     69 #include <sys/systm.h>
     70 #include <sys/proc.h>
     71 #include <sys/vnode.h>
     72 #include <sys/signalvar.h>
     73 #include <sys/syslog.h>
     74 #include <sys/timetc.h>
     75 #include <sys/timex.h>
     76 #include <sys/kauth.h>
     77 #include <sys/mount.h>
     78 #include <sys/syscallargs.h>
     79 #include <sys/cpu.h>
     80 
     81 #include <uvm/uvm_extern.h>
     82 
     83 static void	timer_intr(void *);
     84 static void	itimerfire(struct ptimer *);
     85 static void	itimerfree(struct ptimers *, int);
     86 
     87 kmutex_t	time_lock;
     88 kmutex_t	timer_lock;
     89 
     90 static void	*timer_sih;
     91 static TAILQ_HEAD(, ptimer) timer_queue;
     92 
     93 POOL_INIT(ptimer_pool, sizeof(struct ptimer), 0, 0, 0, "ptimerpl",
     94     &pool_allocator_nointr, IPL_NONE);
     95 POOL_INIT(ptimers_pool, sizeof(struct ptimers), 0, 0, 0, "ptimerspl",
     96     &pool_allocator_nointr, IPL_NONE);
     97 
     98 /*
     99  * Initialize timekeeping.
    100  */
    101 void
    102 time_init(void)
    103 {
    104 
    105 	mutex_init(&time_lock, MUTEX_DEFAULT, IPL_NONE);
    106 }
    107 
    108 void
    109 time_init2(void)
    110 {
    111 
    112 	TAILQ_INIT(&timer_queue);
    113 	mutex_init(&timer_lock, MUTEX_DEFAULT, IPL_SCHED);
    114 	timer_sih = softint_establish(SOFTINT_CLOCK | SOFTINT_MPSAFE,
    115 	    timer_intr, NULL);
    116 }
    117 
    118 /* Time of day and interval timer support.
    119  *
    120  * These routines provide the kernel entry points to get and set
    121  * the time-of-day and per-process interval timers.  Subroutines
    122  * here provide support for adding and subtracting timeval structures
    123  * and decrementing interval timers, optionally reloading the interval
    124  * timers when they expire.
    125  */
    126 
    127 /* This function is used by clock_settime and settimeofday */
    128 static int
    129 settime1(struct proc *p, struct timespec *ts, bool check_kauth)
    130 {
    131 	struct timeval delta, tv;
    132 	struct timeval now;
    133 	struct timespec ts1;
    134 	struct bintime btdelta;
    135 	lwp_t *l;
    136 	int s;
    137 
    138 	TIMESPEC_TO_TIMEVAL(&tv, ts);
    139 
    140 	/* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */
    141 	s = splclock();
    142 	microtime(&now);
    143 	timersub(&tv, &now, &delta);
    144 
    145 	if (check_kauth && kauth_authorize_system(kauth_cred_get(),
    146 	    KAUTH_SYSTEM_TIME, KAUTH_REQ_SYSTEM_TIME_SYSTEM, ts, &delta,
    147 	    KAUTH_ARG(check_kauth ? false : true)) != 0) {
    148 		splx(s);
    149 		return (EPERM);
    150 	}
    151 
    152 #ifdef notyet
    153 	if ((delta.tv_sec < 86400) && securelevel > 0) { /* XXX elad - notyet */
    154 		splx(s);
    155 		return (EPERM);
    156 	}
    157 #endif
    158 
    159 	TIMEVAL_TO_TIMESPEC(&tv, &ts1);
    160 	tc_setclock(&ts1);
    161 
    162 	timeradd(&boottime, &delta, &boottime);
    163 
    164 	/*
    165 	 * XXXSMP: There is a short race between setting the time above
    166 	 * and adjusting LWP's run times.  Fixing this properly means
    167 	 * pausing all CPUs while we adjust the clock.
    168 	 */
    169 	timeval2bintime(&delta, &btdelta);
    170 	mutex_enter(proc_lock);
    171 	LIST_FOREACH(l, &alllwp, l_list) {
    172 		lwp_lock(l);
    173 		bintime_add(&l->l_stime, &btdelta);
    174 		lwp_unlock(l);
    175 	}
    176 	mutex_exit(proc_lock);
    177 	resettodr();
    178 	splx(s);
    179 
    180 	return (0);
    181 }
    182 
    183 int
    184 settime(struct proc *p, struct timespec *ts)
    185 {
    186 	return (settime1(p, ts, true));
    187 }
    188 
    189 /* ARGSUSED */
    190 int
    191 sys_clock_gettime(struct lwp *l, const struct sys_clock_gettime_args *uap,
    192     register_t *retval)
    193 {
    194 	/* {
    195 		syscallarg(clockid_t) clock_id;
    196 		syscallarg(struct timespec *) tp;
    197 	} */
    198 	clockid_t clock_id;
    199 	struct timespec ats;
    200 
    201 	clock_id = SCARG(uap, clock_id);
    202 	switch (clock_id) {
    203 	case CLOCK_REALTIME:
    204 		nanotime(&ats);
    205 		break;
    206 	case CLOCK_MONOTONIC:
    207 		nanouptime(&ats);
    208 		break;
    209 	default:
    210 		return (EINVAL);
    211 	}
    212 
    213 	return copyout(&ats, SCARG(uap, tp), sizeof(ats));
    214 }
    215 
    216 /* ARGSUSED */
    217 int
    218 sys_clock_settime(struct lwp *l, const struct sys_clock_settime_args *uap,
    219     register_t *retval)
    220 {
    221 	/* {
    222 		syscallarg(clockid_t) clock_id;
    223 		syscallarg(const struct timespec *) tp;
    224 	} */
    225 
    226 	return clock_settime1(l->l_proc, SCARG(uap, clock_id), SCARG(uap, tp),
    227 	    true);
    228 }
    229 
    230 
    231 int
    232 clock_settime1(struct proc *p, clockid_t clock_id, const struct timespec *tp,
    233     bool check_kauth)
    234 {
    235 	struct timespec ats;
    236 	int error;
    237 
    238 	if ((error = copyin(tp, &ats, sizeof(ats))) != 0)
    239 		return (error);
    240 
    241 	switch (clock_id) {
    242 	case CLOCK_REALTIME:
    243 		if ((error = settime1(p, &ats, check_kauth)) != 0)
    244 			return (error);
    245 		break;
    246 	case CLOCK_MONOTONIC:
    247 		return (EINVAL);	/* read-only clock */
    248 	default:
    249 		return (EINVAL);
    250 	}
    251 
    252 	return 0;
    253 }
    254 
    255 int
    256 sys_clock_getres(struct lwp *l, const struct sys_clock_getres_args *uap,
    257     register_t *retval)
    258 {
    259 	/* {
    260 		syscallarg(clockid_t) clock_id;
    261 		syscallarg(struct timespec *) tp;
    262 	} */
    263 	clockid_t clock_id;
    264 	struct timespec ts;
    265 	int error = 0;
    266 
    267 	clock_id = SCARG(uap, clock_id);
    268 	switch (clock_id) {
    269 	case CLOCK_REALTIME:
    270 	case CLOCK_MONOTONIC:
    271 		ts.tv_sec = 0;
    272 		if (tc_getfrequency() > 1000000000)
    273 			ts.tv_nsec = 1;
    274 		else
    275 			ts.tv_nsec = 1000000000 / tc_getfrequency();
    276 		break;
    277 	default:
    278 		return (EINVAL);
    279 	}
    280 
    281 	if (SCARG(uap, tp))
    282 		error = copyout(&ts, SCARG(uap, tp), sizeof(ts));
    283 
    284 	return error;
    285 }
    286 
    287 /* ARGSUSED */
    288 int
    289 sys_nanosleep(struct lwp *l, const struct sys_nanosleep_args *uap,
    290     register_t *retval)
    291 {
    292 	/* {
    293 		syscallarg(struct timespec *) rqtp;
    294 		syscallarg(struct timespec *) rmtp;
    295 	} */
    296 	struct timespec rmt, rqt;
    297 	int error, error1;
    298 
    299 	error = copyin(SCARG(uap, rqtp), &rqt, sizeof(struct timespec));
    300 	if (error)
    301 		return (error);
    302 
    303 	error = nanosleep1(l, &rqt, SCARG(uap, rmtp) ? &rmt : NULL);
    304 	if (SCARG(uap, rmtp) == NULL || (error != 0 && error != EINTR))
    305 		return error;
    306 
    307 	error1 = copyout(&rmt, SCARG(uap, rmtp), sizeof(rmt));
    308 	return error1 ? error1 : error;
    309 }
    310 
    311 int
    312 nanosleep1(struct lwp *l, struct timespec *rqt, struct timespec *rmt)
    313 {
    314 	struct timespec rmtstart;
    315 	int error, timo;
    316 
    317 	if (itimespecfix(rqt))
    318 		return (EINVAL);
    319 
    320 	timo = tstohz(rqt);
    321 	/*
    322 	 * Avoid inadvertantly sleeping forever
    323 	 */
    324 	if (timo == 0)
    325 		timo = 1;
    326 	getnanouptime(&rmtstart);
    327 again:
    328 	error = kpause("nanoslp", true, timo, NULL);
    329 	if (rmt != NULL || error == 0) {
    330 		struct timespec rmtend;
    331 		struct timespec t0;
    332 		struct timespec *t;
    333 
    334 		getnanouptime(&rmtend);
    335 		t = (rmt != NULL) ? rmt : &t0;
    336 		timespecsub(&rmtend, &rmtstart, t);
    337 		timespecsub(rqt, t, t);
    338 		if (t->tv_sec < 0)
    339 			timespecclear(t);
    340 		if (error == 0) {
    341 			timo = tstohz(t);
    342 			if (timo > 0)
    343 				goto again;
    344 		}
    345 	}
    346 
    347 	if (error == ERESTART)
    348 		error = EINTR;
    349 	if (error == EWOULDBLOCK)
    350 		error = 0;
    351 
    352 	return error;
    353 }
    354 
    355 /* ARGSUSED */
    356 int
    357 sys_gettimeofday(struct lwp *l, const struct sys_gettimeofday_args *uap,
    358     register_t *retval)
    359 {
    360 	/* {
    361 		syscallarg(struct timeval *) tp;
    362 		syscallarg(void *) tzp;		really "struct timezone *";
    363 	} */
    364 	struct timeval atv;
    365 	int error = 0;
    366 	struct timezone tzfake;
    367 
    368 	if (SCARG(uap, tp)) {
    369 		microtime(&atv);
    370 		error = copyout(&atv, SCARG(uap, tp), sizeof(atv));
    371 		if (error)
    372 			return (error);
    373 	}
    374 	if (SCARG(uap, tzp)) {
    375 		/*
    376 		 * NetBSD has no kernel notion of time zone, so we just
    377 		 * fake up a timezone struct and return it if demanded.
    378 		 */
    379 		tzfake.tz_minuteswest = 0;
    380 		tzfake.tz_dsttime = 0;
    381 		error = copyout(&tzfake, SCARG(uap, tzp), sizeof(tzfake));
    382 	}
    383 	return (error);
    384 }
    385 
    386 /* ARGSUSED */
    387 int
    388 sys_settimeofday(struct lwp *l, const struct sys_settimeofday_args *uap,
    389     register_t *retval)
    390 {
    391 	/* {
    392 		syscallarg(const struct timeval *) tv;
    393 		syscallarg(const void *) tzp; really "const struct timezone *";
    394 	} */
    395 
    396 	return settimeofday1(SCARG(uap, tv), true, SCARG(uap, tzp), l, true);
    397 }
    398 
    399 int
    400 settimeofday1(const struct timeval *utv, bool userspace,
    401     const void *utzp, struct lwp *l, bool check_kauth)
    402 {
    403 	struct timeval atv;
    404 	struct timespec ts;
    405 	int error;
    406 
    407 	/* Verify all parameters before changing time. */
    408 
    409 	/*
    410 	 * NetBSD has no kernel notion of time zone, and only an
    411 	 * obsolete program would try to set it, so we log a warning.
    412 	 */
    413 	if (utzp)
    414 		log(LOG_WARNING, "pid %d attempted to set the "
    415 		    "(obsolete) kernel time zone\n", l->l_proc->p_pid);
    416 
    417 	if (utv == NULL)
    418 		return 0;
    419 
    420 	if (userspace) {
    421 		if ((error = copyin(utv, &atv, sizeof(atv))) != 0)
    422 			return error;
    423 		utv = &atv;
    424 	}
    425 
    426 	TIMEVAL_TO_TIMESPEC(utv, &ts);
    427 	return settime1(l->l_proc, &ts, check_kauth);
    428 }
    429 
    430 int	time_adjusted;			/* set if an adjustment is made */
    431 
    432 /* ARGSUSED */
    433 int
    434 sys_adjtime(struct lwp *l, const struct sys_adjtime_args *uap,
    435     register_t *retval)
    436 {
    437 	/* {
    438 		syscallarg(const struct timeval *) delta;
    439 		syscallarg(struct timeval *) olddelta;
    440 	} */
    441 	int error;
    442 
    443 	if ((error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_TIME,
    444 	    KAUTH_REQ_SYSTEM_TIME_ADJTIME, NULL, NULL, NULL)) != 0)
    445 		return (error);
    446 
    447 	return adjtime1(SCARG(uap, delta), SCARG(uap, olddelta), l->l_proc);
    448 }
    449 
    450 int
    451 adjtime1(const struct timeval *delta, struct timeval *olddelta, struct proc *p)
    452 {
    453 	struct timeval atv;
    454 	int error = 0;
    455 
    456 	extern int64_t time_adjtime;  /* in kern_ntptime.c */
    457 
    458 	if (olddelta) {
    459 		mutex_spin_enter(&timecounter_lock);
    460 		atv.tv_sec = time_adjtime / 1000000;
    461 		atv.tv_usec = time_adjtime % 1000000;
    462 		mutex_spin_exit(&timecounter_lock);
    463 		if (atv.tv_usec < 0) {
    464 			atv.tv_usec += 1000000;
    465 			atv.tv_sec--;
    466 		}
    467 		error = copyout(&atv, olddelta, sizeof(struct timeval));
    468 		if (error)
    469 			return (error);
    470 	}
    471 
    472 	if (delta) {
    473 		error = copyin(delta, &atv, sizeof(struct timeval));
    474 		if (error)
    475 			return (error);
    476 
    477 		mutex_spin_enter(&timecounter_lock);
    478 		time_adjtime = (int64_t)atv.tv_sec * 1000000 +
    479 			atv.tv_usec;
    480 		if (time_adjtime) {
    481 			/* We need to save the system time during shutdown */
    482 			time_adjusted |= 1;
    483 		}
    484 		mutex_spin_exit(&timecounter_lock);
    485 	}
    486 
    487 	return error;
    488 }
    489 
    490 /*
    491  * Interval timer support. Both the BSD getitimer() family and the POSIX
    492  * timer_*() family of routines are supported.
    493  *
    494  * All timers are kept in an array pointed to by p_timers, which is
    495  * allocated on demand - many processes don't use timers at all. The
    496  * first three elements in this array are reserved for the BSD timers:
    497  * element 0 is ITIMER_REAL, element 1 is ITIMER_VIRTUAL, and element
    498  * 2 is ITIMER_PROF. The rest may be allocated by the timer_create()
    499  * syscall.
    500  *
    501  * Realtime timers are kept in the ptimer structure as an absolute
    502  * time; virtual time timers are kept as a linked list of deltas.
    503  * Virtual time timers are processed in the hardclock() routine of
    504  * kern_clock.c.  The real time timer is processed by a callout
    505  * routine, called from the softclock() routine.  Since a callout may
    506  * be delayed in real time due to interrupt processing in the system,
    507  * it is possible for the real time timeout routine (realtimeexpire,
    508  * given below), to be delayed in real time past when it is supposed
    509  * to occur.  It does not suffice, therefore, to reload the real timer
    510  * .it_value from the real time timers .it_interval.  Rather, we
    511  * compute the next time in absolute time the timer should go off.  */
    512 
    513 /* Allocate a POSIX realtime timer. */
    514 int
    515 sys_timer_create(struct lwp *l, const struct sys_timer_create_args *uap,
    516     register_t *retval)
    517 {
    518 	/* {
    519 		syscallarg(clockid_t) clock_id;
    520 		syscallarg(struct sigevent *) evp;
    521 		syscallarg(timer_t *) timerid;
    522 	} */
    523 
    524 	return timer_create1(SCARG(uap, timerid), SCARG(uap, clock_id),
    525 	    SCARG(uap, evp), copyin, l);
    526 }
    527 
    528 int
    529 timer_create1(timer_t *tid, clockid_t id, struct sigevent *evp,
    530     copyin_t fetch_event, struct lwp *l)
    531 {
    532 	int error;
    533 	timer_t timerid;
    534 	struct ptimers *pts;
    535 	struct ptimer *pt;
    536 	struct proc *p;
    537 
    538 	p = l->l_proc;
    539 
    540 	if (id < CLOCK_REALTIME || id > CLOCK_PROF)
    541 		return (EINVAL);
    542 
    543 	if ((pts = p->p_timers) == NULL)
    544 		pts = timers_alloc(p);
    545 
    546 	pt = pool_get(&ptimer_pool, PR_WAITOK);
    547 	if (evp != NULL) {
    548 		if (((error =
    549 		    (*fetch_event)(evp, &pt->pt_ev, sizeof(pt->pt_ev))) != 0) ||
    550 		    ((pt->pt_ev.sigev_notify < SIGEV_NONE) ||
    551 			(pt->pt_ev.sigev_notify > SIGEV_SA))) {
    552 			pool_put(&ptimer_pool, pt);
    553 			return (error ? error : EINVAL);
    554 		}
    555 	}
    556 
    557 	/* Find a free timer slot, skipping those reserved for setitimer(). */
    558 	mutex_spin_enter(&timer_lock);
    559 	for (timerid = 3; timerid < TIMER_MAX; timerid++)
    560 		if (pts->pts_timers[timerid] == NULL)
    561 			break;
    562 	if (timerid == TIMER_MAX) {
    563 		mutex_spin_exit(&timer_lock);
    564 		pool_put(&ptimer_pool, pt);
    565 		return EAGAIN;
    566 	}
    567 	if (evp == NULL) {
    568 		pt->pt_ev.sigev_notify = SIGEV_SIGNAL;
    569 		switch (id) {
    570 		case CLOCK_REALTIME:
    571 			pt->pt_ev.sigev_signo = SIGALRM;
    572 			break;
    573 		case CLOCK_VIRTUAL:
    574 			pt->pt_ev.sigev_signo = SIGVTALRM;
    575 			break;
    576 		case CLOCK_PROF:
    577 			pt->pt_ev.sigev_signo = SIGPROF;
    578 			break;
    579 		}
    580 		pt->pt_ev.sigev_value.sival_int = timerid;
    581 	}
    582 	pt->pt_info.ksi_signo = pt->pt_ev.sigev_signo;
    583 	pt->pt_info.ksi_errno = 0;
    584 	pt->pt_info.ksi_code = 0;
    585 	pt->pt_info.ksi_pid = p->p_pid;
    586 	pt->pt_info.ksi_uid = kauth_cred_getuid(l->l_cred);
    587 	pt->pt_info.ksi_value = pt->pt_ev.sigev_value;
    588 	pt->pt_type = id;
    589 	pt->pt_proc = p;
    590 	pt->pt_overruns = 0;
    591 	pt->pt_poverruns = 0;
    592 	pt->pt_entry = timerid;
    593 	pt->pt_queued = false;
    594 	pt->pt_active = 0;
    595 	timerclear(&pt->pt_time.it_value);
    596 	callout_init(&pt->pt_ch, 0);
    597 	pts->pts_timers[timerid] = pt;
    598 	mutex_spin_exit(&timer_lock);
    599 
    600 	return copyout(&timerid, tid, sizeof(timerid));
    601 }
    602 
    603 /* Delete a POSIX realtime timer */
    604 int
    605 sys_timer_delete(struct lwp *l, const struct sys_timer_delete_args *uap,
    606     register_t *retval)
    607 {
    608 	/* {
    609 		syscallarg(timer_t) timerid;
    610 	} */
    611 	struct proc *p = l->l_proc;
    612 	timer_t timerid;
    613 	struct ptimers *pts;
    614 	struct ptimer *pt, *ptn;
    615 
    616 	timerid = SCARG(uap, timerid);
    617 	pts = p->p_timers;
    618 
    619 	if (pts == NULL || timerid < 2 || timerid >= TIMER_MAX)
    620 		return (EINVAL);
    621 
    622 	mutex_spin_enter(&timer_lock);
    623 	if ((pt = pts->pts_timers[timerid]) == NULL) {
    624 		mutex_spin_exit(&timer_lock);
    625 		return (EINVAL);
    626 	}
    627 	if (pt->pt_active) {
    628 		ptn = LIST_NEXT(pt, pt_list);
    629 		LIST_REMOVE(pt, pt_list);
    630 		for ( ; ptn; ptn = LIST_NEXT(ptn, pt_list))
    631 			timeradd(&pt->pt_time.it_value, &ptn->pt_time.it_value,
    632 			    &ptn->pt_time.it_value);
    633 		pt->pt_active = 0;
    634 	}
    635 	itimerfree(pts, timerid);
    636 
    637 	return (0);
    638 }
    639 
    640 /*
    641  * Set up the given timer. The value in pt->pt_time.it_value is taken
    642  * to be an absolute time for CLOCK_REALTIME timers and a relative
    643  * time for virtual timers.
    644  * Must be called at splclock().
    645  */
    646 void
    647 timer_settime(struct ptimer *pt)
    648 {
    649 	struct ptimer *ptn, *pptn;
    650 	struct ptlist *ptl;
    651 
    652 	KASSERT(mutex_owned(&timer_lock));
    653 
    654 	if (pt->pt_type == CLOCK_REALTIME) {
    655 		callout_stop(&pt->pt_ch);
    656 		if (timerisset(&pt->pt_time.it_value)) {
    657 			/*
    658 			 * Don't need to check hzto() return value, here.
    659 			 * callout_reset() does it for us.
    660 			 */
    661 			callout_reset(&pt->pt_ch, hzto(&pt->pt_time.it_value),
    662 			    realtimerexpire, pt);
    663 		}
    664 	} else {
    665 		if (pt->pt_active) {
    666 			ptn = LIST_NEXT(pt, pt_list);
    667 			LIST_REMOVE(pt, pt_list);
    668 			for ( ; ptn; ptn = LIST_NEXT(ptn, pt_list))
    669 				timeradd(&pt->pt_time.it_value,
    670 				    &ptn->pt_time.it_value,
    671 				    &ptn->pt_time.it_value);
    672 		}
    673 		if (timerisset(&pt->pt_time.it_value)) {
    674 			if (pt->pt_type == CLOCK_VIRTUAL)
    675 				ptl = &pt->pt_proc->p_timers->pts_virtual;
    676 			else
    677 				ptl = &pt->pt_proc->p_timers->pts_prof;
    678 
    679 			for (ptn = LIST_FIRST(ptl), pptn = NULL;
    680 			     ptn && timercmp(&pt->pt_time.it_value,
    681 				 &ptn->pt_time.it_value, >);
    682 			     pptn = ptn, ptn = LIST_NEXT(ptn, pt_list))
    683 				timersub(&pt->pt_time.it_value,
    684 				    &ptn->pt_time.it_value,
    685 				    &pt->pt_time.it_value);
    686 
    687 			if (pptn)
    688 				LIST_INSERT_AFTER(pptn, pt, pt_list);
    689 			else
    690 				LIST_INSERT_HEAD(ptl, pt, pt_list);
    691 
    692 			for ( ; ptn ; ptn = LIST_NEXT(ptn, pt_list))
    693 				timersub(&ptn->pt_time.it_value,
    694 				    &pt->pt_time.it_value,
    695 				    &ptn->pt_time.it_value);
    696 
    697 			pt->pt_active = 1;
    698 		} else
    699 			pt->pt_active = 0;
    700 	}
    701 }
    702 
    703 void
    704 timer_gettime(struct ptimer *pt, struct itimerval *aitv)
    705 {
    706 	struct timeval now;
    707 	struct ptimer *ptn;
    708 
    709 	KASSERT(mutex_owned(&timer_lock));
    710 
    711 	*aitv = pt->pt_time;
    712 	if (pt->pt_type == CLOCK_REALTIME) {
    713 		/*
    714 		 * Convert from absolute to relative time in .it_value
    715 		 * part of real time timer.  If time for real time
    716 		 * timer has passed return 0, else return difference
    717 		 * between current time and time for the timer to go
    718 		 * off.
    719 		 */
    720 		if (timerisset(&aitv->it_value)) {
    721 			getmicrotime(&now);
    722 			if (timercmp(&aitv->it_value, &now, <))
    723 				timerclear(&aitv->it_value);
    724 			else
    725 				timersub(&aitv->it_value, &now,
    726 				    &aitv->it_value);
    727 		}
    728 	} else if (pt->pt_active) {
    729 		if (pt->pt_type == CLOCK_VIRTUAL)
    730 			ptn = LIST_FIRST(&pt->pt_proc->p_timers->pts_virtual);
    731 		else
    732 			ptn = LIST_FIRST(&pt->pt_proc->p_timers->pts_prof);
    733 		for ( ; ptn && ptn != pt; ptn = LIST_NEXT(ptn, pt_list))
    734 			timeradd(&aitv->it_value,
    735 			    &ptn->pt_time.it_value, &aitv->it_value);
    736 		KASSERT(ptn != NULL); /* pt should be findable on the list */
    737 	} else
    738 		timerclear(&aitv->it_value);
    739 }
    740 
    741 
    742 
    743 /* Set and arm a POSIX realtime timer */
    744 int
    745 sys_timer_settime(struct lwp *l, const struct sys_timer_settime_args *uap,
    746     register_t *retval)
    747 {
    748 	/* {
    749 		syscallarg(timer_t) timerid;
    750 		syscallarg(int) flags;
    751 		syscallarg(const struct itimerspec *) value;
    752 		syscallarg(struct itimerspec *) ovalue;
    753 	} */
    754 	int error;
    755 	struct itimerspec value, ovalue, *ovp = NULL;
    756 
    757 	if ((error = copyin(SCARG(uap, value), &value,
    758 	    sizeof(struct itimerspec))) != 0)
    759 		return (error);
    760 
    761 	if (SCARG(uap, ovalue))
    762 		ovp = &ovalue;
    763 
    764 	if ((error = dotimer_settime(SCARG(uap, timerid), &value, ovp,
    765 	    SCARG(uap, flags), l->l_proc)) != 0)
    766 		return error;
    767 
    768 	if (ovp)
    769 		return copyout(&ovalue, SCARG(uap, ovalue),
    770 		    sizeof(struct itimerspec));
    771 	return 0;
    772 }
    773 
    774 int
    775 dotimer_settime(int timerid, struct itimerspec *value,
    776     struct itimerspec *ovalue, int flags, struct proc *p)
    777 {
    778 	struct timeval now;
    779 	struct itimerval val, oval;
    780 	struct ptimers *pts;
    781 	struct ptimer *pt;
    782 
    783 	pts = p->p_timers;
    784 
    785 	if (pts == NULL || timerid < 2 || timerid >= TIMER_MAX)
    786 		return EINVAL;
    787 	TIMESPEC_TO_TIMEVAL(&val.it_value, &value->it_value);
    788 	TIMESPEC_TO_TIMEVAL(&val.it_interval, &value->it_interval);
    789 	if (itimerfix(&val.it_value) || itimerfix(&val.it_interval))
    790 		return (EINVAL);
    791 
    792 	mutex_spin_enter(&timer_lock);
    793 	if ((pt = pts->pts_timers[timerid]) == NULL) {
    794 		mutex_spin_exit(&timer_lock);
    795 		return (EINVAL);
    796 	}
    797 
    798 	oval = pt->pt_time;
    799 	pt->pt_time = val;
    800 
    801 	/*
    802 	 * If we've been passed a relative time for a realtime timer,
    803 	 * convert it to absolute; if an absolute time for a virtual
    804 	 * timer, convert it to relative and make sure we don't set it
    805 	 * to zero, which would cancel the timer, or let it go
    806 	 * negative, which would confuse the comparison tests.
    807 	 */
    808 	if (timerisset(&pt->pt_time.it_value)) {
    809 		if (pt->pt_type == CLOCK_REALTIME) {
    810 			if ((flags & TIMER_ABSTIME) == 0) {
    811 				getmicrotime(&now);
    812 				timeradd(&pt->pt_time.it_value, &now,
    813 				    &pt->pt_time.it_value);
    814 			}
    815 		} else {
    816 			if ((flags & TIMER_ABSTIME) != 0) {
    817 				getmicrotime(&now);
    818 				timersub(&pt->pt_time.it_value, &now,
    819 				    &pt->pt_time.it_value);
    820 				if (!timerisset(&pt->pt_time.it_value) ||
    821 				    pt->pt_time.it_value.tv_sec < 0) {
    822 					pt->pt_time.it_value.tv_sec = 0;
    823 					pt->pt_time.it_value.tv_usec = 1;
    824 				}
    825 			}
    826 		}
    827 	}
    828 
    829 	timer_settime(pt);
    830 	mutex_spin_exit(&timer_lock);
    831 
    832 	if (ovalue) {
    833 		TIMEVAL_TO_TIMESPEC(&oval.it_value, &ovalue->it_value);
    834 		TIMEVAL_TO_TIMESPEC(&oval.it_interval, &ovalue->it_interval);
    835 	}
    836 
    837 	return (0);
    838 }
    839 
    840 /* Return the time remaining until a POSIX timer fires. */
    841 int
    842 sys_timer_gettime(struct lwp *l, const struct sys_timer_gettime_args *uap,
    843     register_t *retval)
    844 {
    845 	/* {
    846 		syscallarg(timer_t) timerid;
    847 		syscallarg(struct itimerspec *) value;
    848 	} */
    849 	struct itimerspec its;
    850 	int error;
    851 
    852 	if ((error = dotimer_gettime(SCARG(uap, timerid), l->l_proc,
    853 	    &its)) != 0)
    854 		return error;
    855 
    856 	return copyout(&its, SCARG(uap, value), sizeof(its));
    857 }
    858 
    859 int
    860 dotimer_gettime(int timerid, struct proc *p, struct itimerspec *its)
    861 {
    862 	struct ptimer *pt;
    863 	struct ptimers *pts;
    864 	struct itimerval aitv;
    865 
    866 	pts = p->p_timers;
    867 	if (pts == NULL || timerid < 2 || timerid >= TIMER_MAX)
    868 		return (EINVAL);
    869 	mutex_spin_enter(&timer_lock);
    870 	if ((pt = pts->pts_timers[timerid]) == NULL) {
    871 		mutex_spin_exit(&timer_lock);
    872 		return (EINVAL);
    873 	}
    874 	timer_gettime(pt, &aitv);
    875 	mutex_spin_exit(&timer_lock);
    876 
    877 	TIMEVAL_TO_TIMESPEC(&aitv.it_interval, &its->it_interval);
    878 	TIMEVAL_TO_TIMESPEC(&aitv.it_value, &its->it_value);
    879 
    880 	return 0;
    881 }
    882 
    883 /*
    884  * Return the count of the number of times a periodic timer expired
    885  * while a notification was already pending. The counter is reset when
    886  * a timer expires and a notification can be posted.
    887  */
    888 int
    889 sys_timer_getoverrun(struct lwp *l, const struct sys_timer_getoverrun_args *uap,
    890     register_t *retval)
    891 {
    892 	/* {
    893 		syscallarg(timer_t) timerid;
    894 	} */
    895 	struct proc *p = l->l_proc;
    896 	struct ptimers *pts;
    897 	int timerid;
    898 	struct ptimer *pt;
    899 
    900 	timerid = SCARG(uap, timerid);
    901 
    902 	pts = p->p_timers;
    903 	if (pts == NULL || timerid < 2 || timerid >= TIMER_MAX)
    904 		return (EINVAL);
    905 	mutex_spin_enter(&timer_lock);
    906 	if ((pt = pts->pts_timers[timerid]) == NULL) {
    907 		mutex_spin_exit(&timer_lock);
    908 		return (EINVAL);
    909 	}
    910 	*retval = pt->pt_poverruns;
    911 	mutex_spin_exit(&timer_lock);
    912 
    913 	return (0);
    914 }
    915 
    916 /*
    917  * Real interval timer expired:
    918  * send process whose timer expired an alarm signal.
    919  * If time is not set up to reload, then just return.
    920  * Else compute next time timer should go off which is > current time.
    921  * This is where delay in processing this timeout causes multiple
    922  * SIGALRM calls to be compressed into one.
    923  */
    924 void
    925 realtimerexpire(void *arg)
    926 {
    927 	struct timeval now;
    928 	struct ptimer *pt;
    929 
    930 	pt = arg;
    931 
    932 	mutex_spin_enter(&timer_lock);
    933 	itimerfire(pt);
    934 
    935 	if (!timerisset(&pt->pt_time.it_interval)) {
    936 		timerclear(&pt->pt_time.it_value);
    937 		mutex_spin_exit(&timer_lock);
    938 		return;
    939 	}
    940 	for (;;) {
    941 		timeradd(&pt->pt_time.it_value,
    942 		    &pt->pt_time.it_interval, &pt->pt_time.it_value);
    943 		getmicrotime(&now);
    944 		if (timercmp(&pt->pt_time.it_value, &now, >)) {
    945 			/*
    946 			 * Don't need to check hzto() return value, here.
    947 			 * callout_reset() does it for us.
    948 			 */
    949 			callout_reset(&pt->pt_ch, hzto(&pt->pt_time.it_value),
    950 			    realtimerexpire, pt);
    951 			mutex_spin_exit(&timer_lock);
    952 			return;
    953 		}
    954 		mutex_spin_exit(&timer_lock);
    955 		pt->pt_overruns++;
    956 		mutex_spin_enter(&timer_lock);
    957 	}
    958 }
    959 
    960 /* BSD routine to get the value of an interval timer. */
    961 /* ARGSUSED */
    962 int
    963 sys_getitimer(struct lwp *l, const struct sys_getitimer_args *uap,
    964     register_t *retval)
    965 {
    966 	/* {
    967 		syscallarg(int) which;
    968 		syscallarg(struct itimerval *) itv;
    969 	} */
    970 	struct proc *p = l->l_proc;
    971 	struct itimerval aitv;
    972 	int error;
    973 
    974 	error = dogetitimer(p, SCARG(uap, which), &aitv);
    975 	if (error)
    976 		return error;
    977 	return (copyout(&aitv, SCARG(uap, itv), sizeof(struct itimerval)));
    978 }
    979 
    980 int
    981 dogetitimer(struct proc *p, int which, struct itimerval *itvp)
    982 {
    983 	struct ptimers *pts;
    984 	struct ptimer *pt;
    985 
    986 	if ((u_int)which > ITIMER_PROF)
    987 		return (EINVAL);
    988 
    989 	mutex_spin_enter(&timer_lock);
    990 	pts = p->p_timers;
    991 	if (pts == NULL || (pt = pts->pts_timers[which]) == NULL) {
    992 		timerclear(&itvp->it_value);
    993 		timerclear(&itvp->it_interval);
    994 	} else
    995 		timer_gettime(pt, itvp);
    996 	mutex_spin_exit(&timer_lock);
    997 
    998 	return 0;
    999 }
   1000 
   1001 /* BSD routine to set/arm an interval timer. */
   1002 /* ARGSUSED */
   1003 int
   1004 sys_setitimer(struct lwp *l, const struct sys_setitimer_args *uap,
   1005     register_t *retval)
   1006 {
   1007 	/* {
   1008 		syscallarg(int) which;
   1009 		syscallarg(const struct itimerval *) itv;
   1010 		syscallarg(struct itimerval *) oitv;
   1011 	} */
   1012 	struct proc *p = l->l_proc;
   1013 	int which = SCARG(uap, which);
   1014 	struct sys_getitimer_args getargs;
   1015 	const struct itimerval *itvp;
   1016 	struct itimerval aitv;
   1017 	int error;
   1018 
   1019 	if ((u_int)which > ITIMER_PROF)
   1020 		return (EINVAL);
   1021 	itvp = SCARG(uap, itv);
   1022 	if (itvp &&
   1023 	    (error = copyin(itvp, &aitv, sizeof(struct itimerval)) != 0))
   1024 		return (error);
   1025 	if (SCARG(uap, oitv) != NULL) {
   1026 		SCARG(&getargs, which) = which;
   1027 		SCARG(&getargs, itv) = SCARG(uap, oitv);
   1028 		if ((error = sys_getitimer(l, &getargs, retval)) != 0)
   1029 			return (error);
   1030 	}
   1031 	if (itvp == 0)
   1032 		return (0);
   1033 
   1034 	return dosetitimer(p, which, &aitv);
   1035 }
   1036 
   1037 int
   1038 dosetitimer(struct proc *p, int which, struct itimerval *itvp)
   1039 {
   1040 	struct timeval now;
   1041 	struct ptimers *pts;
   1042 	struct ptimer *pt, *spare;
   1043 
   1044 	if (itimerfix(&itvp->it_value) || itimerfix(&itvp->it_interval))
   1045 		return (EINVAL);
   1046 
   1047 	/*
   1048 	 * Don't bother allocating data structures if the process just
   1049 	 * wants to clear the timer.
   1050 	 */
   1051 	spare = NULL;
   1052 	pts = p->p_timers;
   1053  retry:
   1054 	if (!timerisset(&itvp->it_value) && (pts == NULL ||
   1055 	    pts->pts_timers[which] == NULL))
   1056 		return (0);
   1057 	if (pts == NULL)
   1058 		pts = timers_alloc(p);
   1059 	mutex_spin_enter(&timer_lock);
   1060 	pt = pts->pts_timers[which];
   1061 	if (pt == NULL) {
   1062 		if (spare == NULL) {
   1063 			mutex_spin_exit(&timer_lock);
   1064 			spare = pool_get(&ptimer_pool, PR_WAITOK);
   1065 			goto retry;
   1066 		}
   1067 		pt = spare;
   1068 		spare = NULL;
   1069 		pt->pt_ev.sigev_notify = SIGEV_SIGNAL;
   1070 		pt->pt_ev.sigev_value.sival_int = which;
   1071 		pt->pt_overruns = 0;
   1072 		pt->pt_proc = p;
   1073 		pt->pt_type = which;
   1074 		pt->pt_entry = which;
   1075 		pt->pt_active = 0;
   1076 		pt->pt_queued = false;
   1077 		callout_init(&pt->pt_ch, CALLOUT_MPSAFE);
   1078 		switch (which) {
   1079 		case ITIMER_REAL:
   1080 			pt->pt_ev.sigev_signo = SIGALRM;
   1081 			break;
   1082 		case ITIMER_VIRTUAL:
   1083 			pt->pt_ev.sigev_signo = SIGVTALRM;
   1084 			break;
   1085 		case ITIMER_PROF:
   1086 			pt->pt_ev.sigev_signo = SIGPROF;
   1087 			break;
   1088 		}
   1089 		pts->pts_timers[which] = pt;
   1090 	}
   1091 	pt->pt_time = *itvp;
   1092 
   1093 	if ((which == ITIMER_REAL) && timerisset(&pt->pt_time.it_value)) {
   1094 		/* Convert to absolute time */
   1095 		/* XXX need to wrap in splclock for timecounters case? */
   1096 		getmicrotime(&now);
   1097 		timeradd(&pt->pt_time.it_value, &now, &pt->pt_time.it_value);
   1098 	}
   1099 	timer_settime(pt);
   1100 	mutex_spin_exit(&timer_lock);
   1101 	if (spare != NULL)
   1102 		pool_put(&ptimer_pool, spare);
   1103 
   1104 	return (0);
   1105 }
   1106 
   1107 /* Utility routines to manage the array of pointers to timers. */
   1108 struct ptimers *
   1109 timers_alloc(struct proc *p)
   1110 {
   1111 	struct ptimers *pts;
   1112 	int i;
   1113 
   1114 	pts = pool_get(&ptimers_pool, PR_WAITOK);
   1115 	LIST_INIT(&pts->pts_virtual);
   1116 	LIST_INIT(&pts->pts_prof);
   1117 	for (i = 0; i < TIMER_MAX; i++)
   1118 		pts->pts_timers[i] = NULL;
   1119 	pts->pts_fired = 0;
   1120 	mutex_spin_enter(&timer_lock);
   1121 	if (p->p_timers == NULL) {
   1122 		p->p_timers = pts;
   1123 		mutex_spin_exit(&timer_lock);
   1124 		return pts;
   1125 	}
   1126 	mutex_spin_exit(&timer_lock);
   1127 	pool_put(&ptimers_pool, pts);
   1128 	return p->p_timers;
   1129 }
   1130 
   1131 /*
   1132  * Clean up the per-process timers. If "which" is set to TIMERS_ALL,
   1133  * then clean up all timers and free all the data structures. If
   1134  * "which" is set to TIMERS_POSIX, only clean up the timers allocated
   1135  * by timer_create(), not the BSD setitimer() timers, and only free the
   1136  * structure if none of those remain.
   1137  */
   1138 void
   1139 timers_free(struct proc *p, int which)
   1140 {
   1141 	struct ptimers *pts;
   1142 	struct ptimer *ptn;
   1143 	struct timeval tv;
   1144 	int i;
   1145 
   1146 	if (p->p_timers == NULL)
   1147 		return;
   1148 
   1149 	pts = p->p_timers;
   1150 	mutex_spin_enter(&timer_lock);
   1151 	if (which == TIMERS_ALL) {
   1152 		p->p_timers = NULL;
   1153 		i = 0;
   1154 	} else {
   1155 		timerclear(&tv);
   1156 		for (ptn = LIST_FIRST(&pts->pts_virtual);
   1157 		     ptn && ptn != pts->pts_timers[ITIMER_VIRTUAL];
   1158 		     ptn = LIST_NEXT(ptn, pt_list))
   1159 			timeradd(&tv, &ptn->pt_time.it_value, &tv);
   1160 		LIST_FIRST(&pts->pts_virtual) = NULL;
   1161 		if (ptn) {
   1162 			timeradd(&tv, &ptn->pt_time.it_value,
   1163 			    &ptn->pt_time.it_value);
   1164 			LIST_INSERT_HEAD(&pts->pts_virtual, ptn, pt_list);
   1165 		}
   1166 		timerclear(&tv);
   1167 		for (ptn = LIST_FIRST(&pts->pts_prof);
   1168 		     ptn && ptn != pts->pts_timers[ITIMER_PROF];
   1169 		     ptn = LIST_NEXT(ptn, pt_list))
   1170 			timeradd(&tv, &ptn->pt_time.it_value, &tv);
   1171 		LIST_FIRST(&pts->pts_prof) = NULL;
   1172 		if (ptn) {
   1173 			timeradd(&tv, &ptn->pt_time.it_value,
   1174 			    &ptn->pt_time.it_value);
   1175 			LIST_INSERT_HEAD(&pts->pts_prof, ptn, pt_list);
   1176 		}
   1177 		i = 3;
   1178 	}
   1179 	for ( ; i < TIMER_MAX; i++) {
   1180 		if (pts->pts_timers[i] != NULL) {
   1181 			itimerfree(pts, i);
   1182 			mutex_spin_enter(&timer_lock);
   1183 		}
   1184 	}
   1185 	if (pts->pts_timers[0] == NULL && pts->pts_timers[1] == NULL &&
   1186 	    pts->pts_timers[2] == NULL) {
   1187 		p->p_timers = NULL;
   1188 		mutex_spin_exit(&timer_lock);
   1189 		pool_put(&ptimers_pool, pts);
   1190 	} else
   1191 		mutex_spin_exit(&timer_lock);
   1192 }
   1193 
   1194 static void
   1195 itimerfree(struct ptimers *pts, int index)
   1196 {
   1197 	struct ptimer *pt;
   1198 
   1199 	KASSERT(mutex_owned(&timer_lock));
   1200 
   1201 	pt = pts->pts_timers[index];
   1202 	pts->pts_timers[index] = NULL;
   1203 	if (pt->pt_type == CLOCK_REALTIME)
   1204 		callout_halt(&pt->pt_ch, &timer_lock);
   1205 	else if (pt->pt_queued)
   1206 		TAILQ_REMOVE(&timer_queue, pt, pt_chain);
   1207 	mutex_spin_exit(&timer_lock);
   1208 	callout_destroy(&pt->pt_ch);
   1209 	pool_put(&ptimer_pool, pt);
   1210 }
   1211 
   1212 /*
   1213  * Decrement an interval timer by a specified number
   1214  * of microseconds, which must be less than a second,
   1215  * i.e. < 1000000.  If the timer expires, then reload
   1216  * it.  In this case, carry over (usec - old value) to
   1217  * reduce the value reloaded into the timer so that
   1218  * the timer does not drift.  This routine assumes
   1219  * that it is called in a context where the timers
   1220  * on which it is operating cannot change in value.
   1221  */
   1222 static int
   1223 itimerdecr(struct ptimer *pt, int usec)
   1224 {
   1225 	struct itimerval *itp;
   1226 
   1227 	KASSERT(mutex_owned(&timer_lock));
   1228 
   1229 	itp = &pt->pt_time;
   1230 	if (itp->it_value.tv_usec < usec) {
   1231 		if (itp->it_value.tv_sec == 0) {
   1232 			/* expired, and already in next interval */
   1233 			usec -= itp->it_value.tv_usec;
   1234 			goto expire;
   1235 		}
   1236 		itp->it_value.tv_usec += 1000000;
   1237 		itp->it_value.tv_sec--;
   1238 	}
   1239 	itp->it_value.tv_usec -= usec;
   1240 	usec = 0;
   1241 	if (timerisset(&itp->it_value))
   1242 		return (1);
   1243 	/* expired, exactly at end of interval */
   1244 expire:
   1245 	if (timerisset(&itp->it_interval)) {
   1246 		itp->it_value = itp->it_interval;
   1247 		itp->it_value.tv_usec -= usec;
   1248 		if (itp->it_value.tv_usec < 0) {
   1249 			itp->it_value.tv_usec += 1000000;
   1250 			itp->it_value.tv_sec--;
   1251 		}
   1252 		timer_settime(pt);
   1253 	} else
   1254 		itp->it_value.tv_usec = 0;		/* sec is already 0 */
   1255 	return (0);
   1256 }
   1257 
   1258 static void
   1259 itimerfire(struct ptimer *pt)
   1260 {
   1261 
   1262 	KASSERT(mutex_owned(&timer_lock));
   1263 
   1264 	/*
   1265 	 * XXX Can overrun, but we don't do signal queueing yet, anyway.
   1266 	 * XXX Relying on the clock interrupt is stupid.
   1267 	 */
   1268 	if (pt->pt_ev.sigev_notify != SIGEV_SIGNAL || pt->pt_queued)
   1269 		return;
   1270 	TAILQ_INSERT_TAIL(&timer_queue, pt, pt_chain);
   1271 	pt->pt_queued = true;
   1272 	softint_schedule(timer_sih);
   1273 }
   1274 
   1275 void
   1276 timer_tick(lwp_t *l, bool user)
   1277 {
   1278 	struct ptimers *pts;
   1279 	struct ptimer *pt;
   1280 	proc_t *p;
   1281 
   1282 	p = l->l_proc;
   1283 	if (p->p_timers == NULL)
   1284 		return;
   1285 
   1286 	mutex_spin_enter(&timer_lock);
   1287 	if ((pts = l->l_proc->p_timers) != NULL) {
   1288 		/*
   1289 		 * Run current process's virtual and profile time, as needed.
   1290 		 */
   1291 		if (user && (pt = LIST_FIRST(&pts->pts_virtual)) != NULL)
   1292 			if (itimerdecr(pt, tick) == 0)
   1293 				itimerfire(pt);
   1294 		if ((pt = LIST_FIRST(&pts->pts_prof)) != NULL)
   1295 			if (itimerdecr(pt, tick) == 0)
   1296 				itimerfire(pt);
   1297 	}
   1298 	mutex_spin_exit(&timer_lock);
   1299 }
   1300 
   1301 static void
   1302 timer_intr(void *cookie)
   1303 {
   1304 	ksiginfo_t ksi;
   1305 	struct ptimer *pt;
   1306 	proc_t *p;
   1307 
   1308 	mutex_spin_enter(&timer_lock);
   1309 	while ((pt = TAILQ_FIRST(&timer_queue)) != NULL) {
   1310 		TAILQ_REMOVE(&timer_queue, pt, pt_chain);
   1311 		KASSERT(pt->pt_queued);
   1312 		pt->pt_queued = false;
   1313 
   1314 		if (pt->pt_ev.sigev_notify != SIGEV_SIGNAL)
   1315 			continue;
   1316 		p = pt->pt_proc;
   1317 		if (pt->pt_proc->p_timers == NULL) {
   1318 			/* Process is dying. */
   1319 			continue;
   1320 		}
   1321 		if (sigismember(&p->p_sigpend.sp_set, pt->pt_ev.sigev_signo)) {
   1322 			pt->pt_overruns++;
   1323 			continue;
   1324 		}
   1325 
   1326 		KSI_INIT(&ksi);
   1327 		ksi.ksi_signo = pt->pt_ev.sigev_signo;
   1328 		ksi.ksi_code = SI_TIMER;
   1329 		ksi.ksi_value = pt->pt_ev.sigev_value;
   1330 		pt->pt_poverruns = pt->pt_overruns;
   1331 		pt->pt_overruns = 0;
   1332 		mutex_spin_exit(&timer_lock);
   1333 
   1334 		mutex_enter(proc_lock);
   1335 		kpsignal(p, &ksi, NULL);
   1336 		mutex_exit(proc_lock);
   1337 
   1338 		mutex_spin_enter(&timer_lock);
   1339 	}
   1340 	mutex_spin_exit(&timer_lock);
   1341 }
   1342 
   1343 /*
   1344  * ratecheck(): simple time-based rate-limit checking.  see ratecheck(9)
   1345  * for usage and rationale.
   1346  */
   1347 int
   1348 ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
   1349 {
   1350 	struct timeval tv, delta;
   1351 	int rv = 0;
   1352 
   1353 	getmicrouptime(&tv);
   1354 	timersub(&tv, lasttime, &delta);
   1355 
   1356 	/*
   1357 	 * check for 0,0 is so that the message will be seen at least once,
   1358 	 * even if interval is huge.
   1359 	 */
   1360 	if (timercmp(&delta, mininterval, >=) ||
   1361 	    (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
   1362 		*lasttime = tv;
   1363 		rv = 1;
   1364 	}
   1365 
   1366 	return (rv);
   1367 }
   1368 
   1369 /*
   1370  * ppsratecheck(): packets (or events) per second limitation.
   1371  */
   1372 int
   1373 ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
   1374 {
   1375 	struct timeval tv, delta;
   1376 	int rv;
   1377 
   1378 	getmicrouptime(&tv);
   1379 	timersub(&tv, lasttime, &delta);
   1380 
   1381 	/*
   1382 	 * check for 0,0 is so that the message will be seen at least once.
   1383 	 * if more than one second have passed since the last update of
   1384 	 * lasttime, reset the counter.
   1385 	 *
   1386 	 * we do increment *curpps even in *curpps < maxpps case, as some may
   1387 	 * try to use *curpps for stat purposes as well.
   1388 	 */
   1389 	if ((lasttime->tv_sec == 0 && lasttime->tv_usec == 0) ||
   1390 	    delta.tv_sec >= 1) {
   1391 		*lasttime = tv;
   1392 		*curpps = 0;
   1393 	}
   1394 	if (maxpps < 0)
   1395 		rv = 1;
   1396 	else if (*curpps < maxpps)
   1397 		rv = 1;
   1398 	else
   1399 		rv = 0;
   1400 
   1401 #if 1 /*DIAGNOSTIC?*/
   1402 	/* be careful about wrap-around */
   1403 	if (*curpps + 1 > *curpps)
   1404 		*curpps = *curpps + 1;
   1405 #else
   1406 	/*
   1407 	 * assume that there's not too many calls to this function.
   1408 	 * not sure if the assumption holds, as it depends on *caller's*
   1409 	 * behavior, not the behavior of this function.
   1410 	 * IMHO it is wrong to make assumption on the caller's behavior,
   1411 	 * so the above #if is #if 1, not #ifdef DIAGNOSTIC.
   1412 	 */
   1413 	*curpps = *curpps + 1;
   1414 #endif
   1415 
   1416 	return (rv);
   1417 }
   1418