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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)kern_time.c 8.1 (Berkeley) 6/10/93 34 * $FreeBSD: src/sys/kern/kern_time.c,v 1.68.2.1 2002/10/01 08:00:41 bde Exp $ 35 */ 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/buf.h> 40 #include <sys/sysproto.h> 41 #include <sys/resourcevar.h> 42 #include <sys/signalvar.h> 43 #include <sys/kernel.h> 44 #include <sys/sysent.h> 45 #include <sys/sysunion.h> 46 #include <sys/proc.h> 47 #include <sys/priv.h> 48 #include <sys/time.h> 49 #include <sys/vnode.h> 50 #include <sys/sysctl.h> 51 #include <sys/kern_syscall.h> 52 #include <vm/vm.h> 53 #include <vm/vm_extern.h> 54 55 #include <sys/msgport2.h> 56 #include <sys/thread2.h> 57 #include <sys/mplock2.h> 58 59 struct timezone tz; 60 61 /* 62 * Time of day and interval timer support. 63 * 64 * These routines provide the kernel entry points to get and set 65 * the time-of-day and per-process interval timers. Subroutines 66 * here provide support for adding and subtracting timeval structures 67 * and decrementing interval timers, optionally reloading the interval 68 * timers when they expire. 69 */ 70 71 static int settime(struct timeval *); 72 static void timevalfix(struct timeval *); 73 74 /* 75 * Nanosleep tries very hard to sleep for a precisely requested time 76 * interval, down to 1uS. The administrator can impose a minimum delay 77 * and a delay below which we hard-loop instead of initiate a timer 78 * interrupt and sleep. 79 * 80 * For machines under high loads it might be beneficial to increase min_us 81 * to e.g. 1000uS (1ms) so spining processes sleep meaningfully. 82 */ 83 static int nanosleep_min_us = 10; 84 static int nanosleep_hard_us = 100; 85 static int gettimeofday_quick = 0; 86 SYSCTL_INT(_kern, OID_AUTO, nanosleep_min_us, CTLFLAG_RW, 87 &nanosleep_min_us, 0, "") 88 SYSCTL_INT(_kern, OID_AUTO, nanosleep_hard_us, CTLFLAG_RW, 89 &nanosleep_hard_us, 0, "") 90 SYSCTL_INT(_kern, OID_AUTO, gettimeofday_quick, CTLFLAG_RW, 91 &gettimeofday_quick, 0, "") 92 93 static int 94 settime(struct timeval *tv) 95 { 96 struct timeval delta, tv1, tv2; 97 static struct timeval maxtime, laststep; 98 struct timespec ts; 99 int origcpu; 100 101 if ((origcpu = mycpu->gd_cpuid) != 0) 102 lwkt_setcpu_self(globaldata_find(0)); 103 104 crit_enter(); 105 microtime(&tv1); 106 delta = *tv; 107 timevalsub(&delta, &tv1); 108 109 /* 110 * If the system is secure, we do not allow the time to be 111 * set to a value earlier than 1 second less than the highest 112 * time we have yet seen. The worst a miscreant can do in 113 * this circumstance is "freeze" time. He couldn't go 114 * back to the past. 115 * 116 * We similarly do not allow the clock to be stepped more 117 * than one second, nor more than once per second. This allows 118 * a miscreant to make the clock march double-time, but no worse. 119 */ 120 if (securelevel > 1) { 121 if (delta.tv_sec < 0 || delta.tv_usec < 0) { 122 /* 123 * Update maxtime to latest time we've seen. 124 */ 125 if (tv1.tv_sec > maxtime.tv_sec) 126 maxtime = tv1; 127 tv2 = *tv; 128 timevalsub(&tv2, &maxtime); 129 if (tv2.tv_sec < -1) { 130 tv->tv_sec = maxtime.tv_sec - 1; 131 kprintf("Time adjustment clamped to -1 second\n"); 132 } 133 } else { 134 if (tv1.tv_sec == laststep.tv_sec) { 135 crit_exit(); 136 return (EPERM); 137 } 138 if (delta.tv_sec > 1) { 139 tv->tv_sec = tv1.tv_sec + 1; 140 kprintf("Time adjustment clamped to +1 second\n"); 141 } 142 laststep = *tv; 143 } 144 } 145 146 ts.tv_sec = tv->tv_sec; 147 ts.tv_nsec = tv->tv_usec * 1000; 148 set_timeofday(&ts); 149 crit_exit(); 150 151 if (origcpu != 0) 152 lwkt_setcpu_self(globaldata_find(origcpu)); 153 154 resettodr(); 155 return (0); 156 } 157 158 /* 159 * MPSAFE 160 */ 161 int 162 kern_clock_gettime(clockid_t clock_id, struct timespec *ats) 163 { 164 int error = 0; 165 struct proc *p; 166 167 switch(clock_id) { 168 case CLOCK_REALTIME: 169 case CLOCK_REALTIME_PRECISE: 170 nanotime(ats); 171 break; 172 case CLOCK_REALTIME_FAST: 173 getnanotime(ats); 174 break; 175 case CLOCK_MONOTONIC: 176 case CLOCK_MONOTONIC_PRECISE: 177 case CLOCK_UPTIME: 178 case CLOCK_UPTIME_PRECISE: 179 nanouptime(ats); 180 break; 181 case CLOCK_MONOTONIC_FAST: 182 case CLOCK_UPTIME_FAST: 183 getnanouptime(ats); 184 break; 185 case CLOCK_VIRTUAL: 186 p = curproc; 187 ats->tv_sec = p->p_timer[ITIMER_VIRTUAL].it_value.tv_sec; 188 ats->tv_nsec = p->p_timer[ITIMER_VIRTUAL].it_value.tv_usec * 189 1000; 190 break; 191 case CLOCK_PROF: 192 p = curproc; 193 ats->tv_sec = p->p_timer[ITIMER_PROF].it_value.tv_sec; 194 ats->tv_nsec = p->p_timer[ITIMER_PROF].it_value.tv_usec * 195 1000; 196 break; 197 case CLOCK_SECOND: 198 ats->tv_sec = time_second; 199 ats->tv_nsec = 0; 200 break; 201 default: 202 error = EINVAL; 203 break; 204 } 205 return (error); 206 } 207 208 /* 209 * MPSAFE 210 */ 211 int 212 sys_clock_gettime(struct clock_gettime_args *uap) 213 { 214 struct timespec ats; 215 int error; 216 217 error = kern_clock_gettime(uap->clock_id, &ats); 218 if (error == 0) 219 error = copyout(&ats, uap->tp, sizeof(ats)); 220 221 return (error); 222 } 223 224 int 225 kern_clock_settime(clockid_t clock_id, struct timespec *ats) 226 { 227 struct thread *td = curthread; 228 struct timeval atv; 229 int error; 230 231 if ((error = priv_check(td, PRIV_CLOCK_SETTIME)) != 0) 232 return (error); 233 if (clock_id != CLOCK_REALTIME) 234 return (EINVAL); 235 if (ats->tv_nsec < 0 || ats->tv_nsec >= 1000000000) 236 return (EINVAL); 237 238 TIMESPEC_TO_TIMEVAL(&atv, ats); 239 error = settime(&atv); 240 return (error); 241 } 242 243 /* 244 * MPALMOSTSAFE 245 */ 246 int 247 sys_clock_settime(struct clock_settime_args *uap) 248 { 249 struct timespec ats; 250 int error; 251 252 if ((error = copyin(uap->tp, &ats, sizeof(ats))) != 0) 253 return (error); 254 255 get_mplock(); 256 error = kern_clock_settime(uap->clock_id, &ats); 257 rel_mplock(); 258 return (error); 259 } 260 261 /* 262 * MPSAFE 263 */ 264 int 265 kern_clock_getres(clockid_t clock_id, struct timespec *ts) 266 { 267 int error; 268 269 switch(clock_id) { 270 case CLOCK_REALTIME: 271 case CLOCK_REALTIME_FAST: 272 case CLOCK_REALTIME_PRECISE: 273 case CLOCK_MONOTONIC: 274 case CLOCK_MONOTONIC_FAST: 275 case CLOCK_MONOTONIC_PRECISE: 276 case CLOCK_UPTIME: 277 case CLOCK_UPTIME_FAST: 278 case CLOCK_UPTIME_PRECISE: 279 /* 280 * Round up the result of the division cheaply 281 * by adding 1. Rounding up is especially important 282 * if rounding down would give 0. Perfect rounding 283 * is unimportant. 284 */ 285 ts->tv_sec = 0; 286 ts->tv_nsec = 1000000000 / sys_cputimer->freq + 1; 287 error = 0; 288 break; 289 case CLOCK_VIRTUAL: 290 case CLOCK_PROF: 291 /* Accurately round up here because we can do so cheaply. */ 292 ts->tv_sec = 0; 293 ts->tv_nsec = (1000000000 + hz - 1) / hz; 294 error = 0; 295 break; 296 case CLOCK_SECOND: 297 ts->tv_sec = 1; 298 ts->tv_nsec = 0; 299 error = 0; 300 break; 301 default: 302 error = EINVAL; 303 break; 304 } 305 306 return(error); 307 } 308 309 /* 310 * MPSAFE 311 */ 312 int 313 sys_clock_getres(struct clock_getres_args *uap) 314 { 315 int error; 316 struct timespec ts; 317 318 error = kern_clock_getres(uap->clock_id, &ts); 319 if (error == 0) 320 error = copyout(&ts, uap->tp, sizeof(ts)); 321 322 return (error); 323 } 324 325 /* 326 * nanosleep1() 327 * 328 * This is a general helper function for nanosleep() (aka sleep() aka 329 * usleep()). 330 * 331 * If there is less then one tick's worth of time left and 332 * we haven't done a yield, or the remaining microseconds is 333 * ridiculously low, do a yield. This avoids having 334 * to deal with systimer overheads when the system is under 335 * heavy loads. If we have done a yield already then use 336 * a systimer and an uninterruptable thread wait. 337 * 338 * If there is more then a tick's worth of time left, 339 * calculate the baseline ticks and use an interruptable 340 * tsleep, then handle the fine-grained delay on the next 341 * loop. This usually results in two sleeps occuring, a long one 342 * and a short one. 343 * 344 * MPSAFE 345 */ 346 static void 347 ns1_systimer(systimer_t info, int in_ipi __unused, 348 struct intrframe *frame __unused) 349 { 350 lwkt_schedule(info->data); 351 } 352 353 int 354 nanosleep1(struct timespec *rqt, struct timespec *rmt) 355 { 356 static int nanowait; 357 struct timespec ts, ts2, ts3; 358 struct timeval tv; 359 int error; 360 361 if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000) 362 return (EINVAL); 363 /* XXX: imho this should return EINVAL at least for tv_sec < 0 */ 364 if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0)) 365 return (0); 366 nanouptime(&ts); 367 timespecadd(&ts, rqt); /* ts = target timestamp compare */ 368 TIMESPEC_TO_TIMEVAL(&tv, rqt); /* tv = sleep interval */ 369 370 for (;;) { 371 int ticks; 372 struct systimer info; 373 374 ticks = tv.tv_usec / ustick; /* approximate */ 375 376 if (tv.tv_sec == 0 && ticks == 0) { 377 thread_t td = curthread; 378 if (tv.tv_usec > 0 && tv.tv_usec < nanosleep_min_us) 379 tv.tv_usec = nanosleep_min_us; 380 if (tv.tv_usec < nanosleep_hard_us) { 381 lwkt_user_yield(); 382 cpu_pause(); 383 } else { 384 crit_enter_quick(td); 385 systimer_init_oneshot(&info, ns1_systimer, 386 td, tv.tv_usec); 387 lwkt_deschedule_self(td); 388 crit_exit_quick(td); 389 lwkt_switch(); 390 systimer_del(&info); /* make sure it's gone */ 391 } 392 error = iscaught(td->td_lwp); 393 } else if (tv.tv_sec == 0) { 394 error = tsleep(&nanowait, PCATCH, "nanslp", ticks); 395 } else { 396 ticks = tvtohz_low(&tv); /* also handles overflow */ 397 error = tsleep(&nanowait, PCATCH, "nanslp", ticks); 398 } 399 nanouptime(&ts2); 400 if (error && error != EWOULDBLOCK) { 401 if (error == ERESTART) 402 error = EINTR; 403 if (rmt != NULL) { 404 timespecsub(&ts, &ts2); 405 if (ts.tv_sec < 0) 406 timespecclear(&ts); 407 *rmt = ts; 408 } 409 return (error); 410 } 411 if (timespeccmp(&ts2, &ts, >=)) 412 return (0); 413 ts3 = ts; 414 timespecsub(&ts3, &ts2); 415 TIMESPEC_TO_TIMEVAL(&tv, &ts3); 416 } 417 } 418 419 /* 420 * MPSAFE 421 */ 422 int 423 sys_nanosleep(struct nanosleep_args *uap) 424 { 425 int error; 426 struct timespec rqt; 427 struct timespec rmt; 428 429 error = copyin(uap->rqtp, &rqt, sizeof(rqt)); 430 if (error) 431 return (error); 432 433 error = nanosleep1(&rqt, &rmt); 434 435 /* 436 * copyout the residual if nanosleep was interrupted. 437 */ 438 if (error && uap->rmtp) { 439 int error2; 440 441 error2 = copyout(&rmt, uap->rmtp, sizeof(rmt)); 442 if (error2) 443 error = error2; 444 } 445 return (error); 446 } 447 448 /* 449 * The gettimeofday() system call is supposed to return a fine-grained 450 * realtime stamp. However, acquiring a fine-grained stamp can create a 451 * bottleneck when multiple cpu cores are trying to accessing e.g. the 452 * HPET hardware timer all at the same time, so we have a sysctl that 453 * allows its behavior to be changed to a more coarse-grained timestamp 454 * which does not have to access a hardware timer. 455 */ 456 int 457 sys_gettimeofday(struct gettimeofday_args *uap) 458 { 459 struct timeval atv; 460 int error = 0; 461 462 if (uap->tp) { 463 if (gettimeofday_quick) 464 getmicrotime(&atv); 465 else 466 microtime(&atv); 467 if ((error = copyout((caddr_t)&atv, (caddr_t)uap->tp, 468 sizeof (atv)))) 469 return (error); 470 } 471 if (uap->tzp) 472 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, 473 sizeof (tz)); 474 return (error); 475 } 476 477 /* 478 * MPALMOSTSAFE 479 */ 480 int 481 sys_settimeofday(struct settimeofday_args *uap) 482 { 483 struct thread *td = curthread; 484 struct timeval atv; 485 struct timezone atz; 486 int error; 487 488 if ((error = priv_check(td, PRIV_SETTIMEOFDAY))) 489 return (error); 490 /* 491 * Verify all parameters before changing time. 492 * 493 * NOTE: We do not allow the time to be set to 0.0, which also by 494 * happy coincidence works around a pkgsrc bulk build bug. 495 */ 496 if (uap->tv) { 497 if ((error = copyin((caddr_t)uap->tv, (caddr_t)&atv, 498 sizeof(atv)))) 499 return (error); 500 if (atv.tv_usec < 0 || atv.tv_usec >= 1000000) 501 return (EINVAL); 502 if (atv.tv_sec == 0 && atv.tv_usec == 0) 503 return (EINVAL); 504 } 505 if (uap->tzp && 506 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz)))) 507 return (error); 508 509 get_mplock(); 510 if (uap->tv && (error = settime(&atv))) { 511 rel_mplock(); 512 return (error); 513 } 514 rel_mplock(); 515 if (uap->tzp) 516 tz = atz; 517 return (0); 518 } 519 520 static void 521 kern_adjtime_common(void) 522 { 523 if ((ntp_delta >= 0 && ntp_delta < ntp_default_tick_delta) || 524 (ntp_delta < 0 && ntp_delta > -ntp_default_tick_delta)) 525 ntp_tick_delta = ntp_delta; 526 else if (ntp_delta > ntp_big_delta) 527 ntp_tick_delta = 10 * ntp_default_tick_delta; 528 else if (ntp_delta < -ntp_big_delta) 529 ntp_tick_delta = -10 * ntp_default_tick_delta; 530 else if (ntp_delta > 0) 531 ntp_tick_delta = ntp_default_tick_delta; 532 else 533 ntp_tick_delta = -ntp_default_tick_delta; 534 } 535 536 void 537 kern_adjtime(int64_t delta, int64_t *odelta) 538 { 539 int origcpu; 540 541 if ((origcpu = mycpu->gd_cpuid) != 0) 542 lwkt_setcpu_self(globaldata_find(0)); 543 544 crit_enter(); 545 *odelta = ntp_delta; 546 ntp_delta = delta; 547 kern_adjtime_common(); 548 crit_exit(); 549 550 if (origcpu != 0) 551 lwkt_setcpu_self(globaldata_find(origcpu)); 552 } 553 554 static void 555 kern_get_ntp_delta(int64_t *delta) 556 { 557 int origcpu; 558 559 if ((origcpu = mycpu->gd_cpuid) != 0) 560 lwkt_setcpu_self(globaldata_find(0)); 561 562 crit_enter(); 563 *delta = ntp_delta; 564 crit_exit(); 565 566 if (origcpu != 0) 567 lwkt_setcpu_self(globaldata_find(origcpu)); 568 } 569 570 void 571 kern_reladjtime(int64_t delta) 572 { 573 int origcpu; 574 575 if ((origcpu = mycpu->gd_cpuid) != 0) 576 lwkt_setcpu_self(globaldata_find(0)); 577 578 crit_enter(); 579 ntp_delta += delta; 580 kern_adjtime_common(); 581 crit_exit(); 582 583 if (origcpu != 0) 584 lwkt_setcpu_self(globaldata_find(origcpu)); 585 } 586 587 static void 588 kern_adjfreq(int64_t rate) 589 { 590 int origcpu; 591 592 if ((origcpu = mycpu->gd_cpuid) != 0) 593 lwkt_setcpu_self(globaldata_find(0)); 594 595 crit_enter(); 596 ntp_tick_permanent = rate; 597 crit_exit(); 598 599 if (origcpu != 0) 600 lwkt_setcpu_self(globaldata_find(origcpu)); 601 } 602 603 /* 604 * MPALMOSTSAFE 605 */ 606 int 607 sys_adjtime(struct adjtime_args *uap) 608 { 609 struct thread *td = curthread; 610 struct timeval atv; 611 int64_t ndelta, odelta; 612 int error; 613 614 if ((error = priv_check(td, PRIV_ADJTIME))) 615 return (error); 616 error = copyin(uap->delta, &atv, sizeof(struct timeval)); 617 if (error) 618 return (error); 619 620 /* 621 * Compute the total correction and the rate at which to apply it. 622 * Round the adjustment down to a whole multiple of the per-tick 623 * delta, so that after some number of incremental changes in 624 * hardclock(), tickdelta will become zero, lest the correction 625 * overshoot and start taking us away from the desired final time. 626 */ 627 ndelta = (int64_t)atv.tv_sec * 1000000000 + atv.tv_usec * 1000; 628 get_mplock(); 629 kern_adjtime(ndelta, &odelta); 630 rel_mplock(); 631 632 if (uap->olddelta) { 633 atv.tv_sec = odelta / 1000000000; 634 atv.tv_usec = odelta % 1000000000 / 1000; 635 copyout(&atv, uap->olddelta, sizeof(struct timeval)); 636 } 637 return (0); 638 } 639 640 static int 641 sysctl_adjtime(SYSCTL_HANDLER_ARGS) 642 { 643 int64_t delta; 644 int error; 645 646 if (req->newptr != NULL) { 647 if (priv_check(curthread, PRIV_ROOT)) 648 return (EPERM); 649 error = SYSCTL_IN(req, &delta, sizeof(delta)); 650 if (error) 651 return (error); 652 kern_reladjtime(delta); 653 } 654 655 if (req->oldptr) 656 kern_get_ntp_delta(&delta); 657 error = SYSCTL_OUT(req, &delta, sizeof(delta)); 658 return (error); 659 } 660 661 /* 662 * delta is in nanoseconds. 663 */ 664 static int 665 sysctl_delta(SYSCTL_HANDLER_ARGS) 666 { 667 int64_t delta, old_delta; 668 int error; 669 670 if (req->newptr != NULL) { 671 if (priv_check(curthread, PRIV_ROOT)) 672 return (EPERM); 673 error = SYSCTL_IN(req, &delta, sizeof(delta)); 674 if (error) 675 return (error); 676 kern_adjtime(delta, &old_delta); 677 } 678 679 if (req->oldptr != NULL) 680 kern_get_ntp_delta(&old_delta); 681 error = SYSCTL_OUT(req, &old_delta, sizeof(old_delta)); 682 return (error); 683 } 684 685 /* 686 * frequency is in nanoseconds per second shifted left 32. 687 * kern_adjfreq() needs it in nanoseconds per tick shifted left 32. 688 */ 689 static int 690 sysctl_adjfreq(SYSCTL_HANDLER_ARGS) 691 { 692 int64_t freqdelta; 693 int error; 694 695 if (req->newptr != NULL) { 696 if (priv_check(curthread, PRIV_ROOT)) 697 return (EPERM); 698 error = SYSCTL_IN(req, &freqdelta, sizeof(freqdelta)); 699 if (error) 700 return (error); 701 702 freqdelta /= hz; 703 kern_adjfreq(freqdelta); 704 } 705 706 if (req->oldptr != NULL) 707 freqdelta = ntp_tick_permanent * hz; 708 error = SYSCTL_OUT(req, &freqdelta, sizeof(freqdelta)); 709 if (error) 710 return (error); 711 712 return (0); 713 } 714 715 SYSCTL_NODE(_kern, OID_AUTO, ntp, CTLFLAG_RW, 0, "NTP related controls"); 716 SYSCTL_PROC(_kern_ntp, OID_AUTO, permanent, 717 CTLTYPE_QUAD|CTLFLAG_RW, 0, 0, 718 sysctl_adjfreq, "Q", "permanent correction per second"); 719 SYSCTL_PROC(_kern_ntp, OID_AUTO, delta, 720 CTLTYPE_QUAD|CTLFLAG_RW, 0, 0, 721 sysctl_delta, "Q", "one-time delta"); 722 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, big_delta, CTLFLAG_RD, 723 &ntp_big_delta, sizeof(ntp_big_delta), "Q", 724 "threshold for fast adjustment"); 725 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, tick_delta, CTLFLAG_RD, 726 &ntp_tick_delta, sizeof(ntp_tick_delta), "LU", 727 "per-tick adjustment"); 728 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, default_tick_delta, CTLFLAG_RD, 729 &ntp_default_tick_delta, sizeof(ntp_default_tick_delta), "LU", 730 "default per-tick adjustment"); 731 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, next_leap_second, CTLFLAG_RW, 732 &ntp_leap_second, sizeof(ntp_leap_second), "LU", 733 "next leap second"); 734 SYSCTL_INT(_kern_ntp, OID_AUTO, insert_leap_second, CTLFLAG_RW, 735 &ntp_leap_insert, 0, "insert or remove leap second"); 736 SYSCTL_PROC(_kern_ntp, OID_AUTO, adjust, 737 CTLTYPE_QUAD|CTLFLAG_RW, 0, 0, 738 sysctl_adjtime, "Q", "relative adjust for delta"); 739 740 /* 741 * Get value of an interval timer. The process virtual and 742 * profiling virtual time timers are kept in the p_stats area, since 743 * they can be swapped out. These are kept internally in the 744 * way they are specified externally: in time until they expire. 745 * 746 * The real time interval timer is kept in the process table slot 747 * for the process, and its value (it_value) is kept as an 748 * absolute time rather than as a delta, so that it is easy to keep 749 * periodic real-time signals from drifting. 750 * 751 * Virtual time timers are processed in the hardclock() routine of 752 * kern_clock.c. The real time timer is processed by a timeout 753 * routine, called from the softclock() routine. Since a callout 754 * may be delayed in real time due to interrupt processing in the system, 755 * it is possible for the real time timeout routine (realitexpire, given below), 756 * to be delayed in real time past when it is supposed to occur. It 757 * does not suffice, therefore, to reload the real timer .it_value from the 758 * real time timers .it_interval. Rather, we compute the next time in 759 * absolute time the timer should go off. 760 * 761 * MPALMOSTSAFE 762 */ 763 int 764 sys_getitimer(struct getitimer_args *uap) 765 { 766 struct proc *p = curproc; 767 struct timeval ctv; 768 struct itimerval aitv; 769 770 if (uap->which > ITIMER_PROF) 771 return (EINVAL); 772 lwkt_gettoken(&p->p_token); 773 if (uap->which == ITIMER_REAL) { 774 /* 775 * Convert from absolute to relative time in .it_value 776 * part of real time timer. If time for real time timer 777 * has passed return 0, else return difference between 778 * current time and time for the timer to go off. 779 */ 780 aitv = p->p_realtimer; 781 if (timevalisset(&aitv.it_value)) { 782 getmicrouptime(&ctv); 783 if (timevalcmp(&aitv.it_value, &ctv, <)) 784 timevalclear(&aitv.it_value); 785 else 786 timevalsub(&aitv.it_value, &ctv); 787 } 788 } else { 789 aitv = p->p_timer[uap->which]; 790 } 791 lwkt_reltoken(&p->p_token); 792 return (copyout(&aitv, uap->itv, sizeof (struct itimerval))); 793 } 794 795 /* 796 * MPALMOSTSAFE 797 */ 798 int 799 sys_setitimer(struct setitimer_args *uap) 800 { 801 struct itimerval aitv; 802 struct timeval ctv; 803 struct itimerval *itvp; 804 struct proc *p = curproc; 805 int error; 806 807 if (uap->which > ITIMER_PROF) 808 return (EINVAL); 809 itvp = uap->itv; 810 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 811 sizeof(struct itimerval)))) 812 return (error); 813 if ((uap->itv = uap->oitv) && 814 (error = sys_getitimer((struct getitimer_args *)uap))) 815 return (error); 816 if (itvp == NULL) 817 return (0); 818 if (itimerfix(&aitv.it_value)) 819 return (EINVAL); 820 if (!timevalisset(&aitv.it_value)) 821 timevalclear(&aitv.it_interval); 822 else if (itimerfix(&aitv.it_interval)) 823 return (EINVAL); 824 lwkt_gettoken(&p->p_token); 825 if (uap->which == ITIMER_REAL) { 826 if (timevalisset(&p->p_realtimer.it_value)) 827 callout_stop_sync(&p->p_ithandle); 828 if (timevalisset(&aitv.it_value)) 829 callout_reset(&p->p_ithandle, 830 tvtohz_high(&aitv.it_value), realitexpire, p); 831 getmicrouptime(&ctv); 832 timevaladd(&aitv.it_value, &ctv); 833 p->p_realtimer = aitv; 834 } else { 835 p->p_timer[uap->which] = aitv; 836 switch(uap->which) { 837 case ITIMER_VIRTUAL: 838 p->p_flags &= ~P_SIGVTALRM; 839 break; 840 case ITIMER_PROF: 841 p->p_flags &= ~P_SIGPROF; 842 break; 843 } 844 } 845 lwkt_reltoken(&p->p_token); 846 return (0); 847 } 848 849 /* 850 * Real interval timer expired: 851 * send process whose timer expired an alarm signal. 852 * If time is not set up to reload, then just return. 853 * Else compute next time timer should go off which is > current time. 854 * This is where delay in processing this timeout causes multiple 855 * SIGALRM calls to be compressed into one. 856 * tvtohz_high() always adds 1 to allow for the time until the next clock 857 * interrupt being strictly less than 1 clock tick, but we don't want 858 * that here since we want to appear to be in sync with the clock 859 * interrupt even when we're delayed. 860 */ 861 void 862 realitexpire(void *arg) 863 { 864 struct proc *p; 865 struct timeval ctv, ntv; 866 867 p = (struct proc *)arg; 868 PHOLD(p); 869 lwkt_gettoken(&p->p_token); 870 ksignal(p, SIGALRM); 871 if (!timevalisset(&p->p_realtimer.it_interval)) { 872 timevalclear(&p->p_realtimer.it_value); 873 goto done; 874 } 875 for (;;) { 876 timevaladd(&p->p_realtimer.it_value, 877 &p->p_realtimer.it_interval); 878 getmicrouptime(&ctv); 879 if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) { 880 ntv = p->p_realtimer.it_value; 881 timevalsub(&ntv, &ctv); 882 callout_reset(&p->p_ithandle, tvtohz_low(&ntv), 883 realitexpire, p); 884 goto done; 885 } 886 } 887 done: 888 lwkt_reltoken(&p->p_token); 889 PRELE(p); 890 } 891 892 /* 893 * Check that a proposed value to load into the .it_value or 894 * .it_interval part of an interval timer is acceptable, and 895 * fix it to have at least minimal value (i.e. if it is less 896 * than the resolution of the clock, round it up.) 897 * 898 * MPSAFE 899 */ 900 int 901 itimerfix(struct timeval *tv) 902 { 903 904 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 905 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 906 return (EINVAL); 907 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < ustick) 908 tv->tv_usec = ustick; 909 return (0); 910 } 911 912 /* 913 * Decrement an interval timer by a specified number 914 * of microseconds, which must be less than a second, 915 * i.e. < 1000000. If the timer expires, then reload 916 * it. In this case, carry over (usec - old value) to 917 * reduce the value reloaded into the timer so that 918 * the timer does not drift. This routine assumes 919 * that it is called in a context where the timers 920 * on which it is operating cannot change in value. 921 */ 922 int 923 itimerdecr(struct itimerval *itp, int usec) 924 { 925 926 if (itp->it_value.tv_usec < usec) { 927 if (itp->it_value.tv_sec == 0) { 928 /* expired, and already in next interval */ 929 usec -= itp->it_value.tv_usec; 930 goto expire; 931 } 932 itp->it_value.tv_usec += 1000000; 933 itp->it_value.tv_sec--; 934 } 935 itp->it_value.tv_usec -= usec; 936 usec = 0; 937 if (timevalisset(&itp->it_value)) 938 return (1); 939 /* expired, exactly at end of interval */ 940 expire: 941 if (timevalisset(&itp->it_interval)) { 942 itp->it_value = itp->it_interval; 943 itp->it_value.tv_usec -= usec; 944 if (itp->it_value.tv_usec < 0) { 945 itp->it_value.tv_usec += 1000000; 946 itp->it_value.tv_sec--; 947 } 948 } else 949 itp->it_value.tv_usec = 0; /* sec is already 0 */ 950 return (0); 951 } 952 953 /* 954 * Add and subtract routines for timevals. 955 * N.B.: subtract routine doesn't deal with 956 * results which are before the beginning, 957 * it just gets very confused in this case. 958 * Caveat emptor. 959 */ 960 void 961 timevaladd(struct timeval *t1, const struct timeval *t2) 962 { 963 964 t1->tv_sec += t2->tv_sec; 965 t1->tv_usec += t2->tv_usec; 966 timevalfix(t1); 967 } 968 969 void 970 timevalsub(struct timeval *t1, const struct timeval *t2) 971 { 972 973 t1->tv_sec -= t2->tv_sec; 974 t1->tv_usec -= t2->tv_usec; 975 timevalfix(t1); 976 } 977 978 static void 979 timevalfix(struct timeval *t1) 980 { 981 982 if (t1->tv_usec < 0) { 983 t1->tv_sec--; 984 t1->tv_usec += 1000000; 985 } 986 if (t1->tv_usec >= 1000000) { 987 t1->tv_sec++; 988 t1->tv_usec -= 1000000; 989 } 990 } 991 992 /* 993 * ratecheck(): simple time-based rate-limit checking. 994 */ 995 int 996 ratecheck(struct timeval *lasttime, const struct timeval *mininterval) 997 { 998 struct timeval tv, delta; 999 int rv = 0; 1000 1001 getmicrouptime(&tv); /* NB: 10ms precision */ 1002 delta = tv; 1003 timevalsub(&delta, lasttime); 1004 1005 /* 1006 * check for 0,0 is so that the message will be seen at least once, 1007 * even if interval is huge. 1008 */ 1009 if (timevalcmp(&delta, mininterval, >=) || 1010 (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) { 1011 *lasttime = tv; 1012 rv = 1; 1013 } 1014 1015 return (rv); 1016 } 1017 1018 /* 1019 * ppsratecheck(): packets (or events) per second limitation. 1020 * 1021 * Return 0 if the limit is to be enforced (e.g. the caller 1022 * should drop a packet because of the rate limitation). 1023 * 1024 * maxpps of 0 always causes zero to be returned. maxpps of -1 1025 * always causes 1 to be returned; this effectively defeats rate 1026 * limiting. 1027 * 1028 * Note that we maintain the struct timeval for compatibility 1029 * with other bsd systems. We reuse the storage and just monitor 1030 * clock ticks for minimal overhead. 1031 */ 1032 int 1033 ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps) 1034 { 1035 int now; 1036 1037 /* 1038 * Reset the last time and counter if this is the first call 1039 * or more than a second has passed since the last update of 1040 * lasttime. 1041 */ 1042 now = ticks; 1043 if (lasttime->tv_sec == 0 || (u_int)(now - lasttime->tv_sec) >= hz) { 1044 lasttime->tv_sec = now; 1045 *curpps = 1; 1046 return (maxpps != 0); 1047 } else { 1048 (*curpps)++; /* NB: ignore potential overflow */ 1049 return (maxpps < 0 || *curpps < maxpps); 1050 } 1051 } 1052 1053