kern_time.c revision 36127
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 * $Id: kern_time.c,v 1.55 1998/05/17 11:52:48 phk Exp $ 35 */ 36 37#include <sys/param.h> 38#include <sys/sysproto.h> 39#include <sys/resourcevar.h> 40#include <sys/signalvar.h> 41#include <sys/kernel.h> 42#include <sys/systm.h> 43#include <sys/sysent.h> 44#include <sys/proc.h> 45#include <sys/time.h> 46#include <sys/vnode.h> 47#include <vm/vm.h> 48#include <vm/vm_extern.h> 49 50struct timezone tz; 51 52/* 53 * Time of day and interval timer support. 54 * 55 * These routines provide the kernel entry points to get and set 56 * the time-of-day and per-process interval timers. Subroutines 57 * here provide support for adding and subtracting timeval structures 58 * and decrementing interval timers, optionally reloading the interval 59 * timers when they expire. 60 */ 61 62static int nanosleep1 __P((struct proc *p, struct timespec *rqt, 63 struct timespec *rmt)); 64static int settime __P((struct timeval *)); 65static void timevalfix __P((struct timeval *)); 66static void no_lease_updatetime __P((int)); 67 68static void 69no_lease_updatetime(deltat) 70 int deltat; 71{ 72} 73 74void (*lease_updatetime) __P((int)) = no_lease_updatetime; 75 76static int 77settime(tv) 78 struct timeval *tv; 79{ 80 struct timeval delta, tv1; 81 struct timespec ts; 82 struct proc *p; 83 int s; 84 85 s = splclock(); 86 microtime(&tv1); 87 delta = *tv; 88 timevalsub(&delta, &tv1); 89 90 /* 91 * If the system is secure, we do not allow the time to be 92 * set to an earlier value (it may be slowed using adjtime, 93 * but not set back). This feature prevent interlopers from 94 * setting arbitrary time stamps on files. 95 */ 96 if (delta.tv_sec < 0 && securelevel > 1) { 97 splx(s); 98 return (EPERM); 99 } 100 101 ts.tv_sec = tv->tv_sec; 102 ts.tv_nsec = tv->tv_usec * 1000; 103 set_timecounter(&ts); 104 (void) splsoftclock(); 105 lease_updatetime(delta.tv_sec); 106 splx(s); 107 resettodr(); 108 return (0); 109} 110 111#ifndef _SYS_SYSPROTO_H_ 112struct clock_gettime_args { 113 clockid_t clock_id; 114 struct timespec *tp; 115}; 116#endif 117 118/* ARGSUSED */ 119int 120clock_gettime(p, uap) 121 struct proc *p; 122 struct clock_gettime_args *uap; 123{ 124 struct timespec ats; 125 126 if (SCARG(uap, clock_id) != CLOCK_REALTIME) 127 return (EINVAL); 128 nanotime(&ats); 129 return (copyout(&ats, SCARG(uap, tp), sizeof(ats))); 130} 131 132#ifndef _SYS_SYSPROTO_H_ 133struct clock_settime_args { 134 clockid_t clock_id; 135 const struct timespec *tp; 136}; 137#endif 138 139/* ARGSUSED */ 140int 141clock_settime(p, uap) 142 struct proc *p; 143 struct clock_settime_args *uap; 144{ 145 struct timeval atv; 146 struct timespec ats; 147 int error; 148 149 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 150 return (error); 151 if (SCARG(uap, clock_id) != CLOCK_REALTIME) 152 return (EINVAL); 153 if ((error = copyin(SCARG(uap, tp), &ats, sizeof(ats))) != 0) 154 return (error); 155 if (ats.tv_nsec < 0 || ats.tv_nsec >= 1000000000) 156 return (EINVAL); 157 /* XXX Don't convert nsec->usec and back */ 158 TIMESPEC_TO_TIMEVAL(&atv, &ats); 159 if ((error = settime(&atv))) 160 return (error); 161 return (0); 162} 163 164#ifndef _SYS_SYSPROTO_H_ 165struct clock_getres_args { 166 clockid_t clock_id; 167 struct timespec *tp; 168}; 169#endif 170 171int 172clock_getres(p, uap) 173 struct proc *p; 174 struct clock_getres_args *uap; 175{ 176 struct timespec ts; 177 int error; 178 179 if (SCARG(uap, clock_id) != CLOCK_REALTIME) 180 return (EINVAL); 181 error = 0; 182 if (SCARG(uap, tp)) { 183 ts.tv_sec = 0; 184 ts.tv_nsec = 1000000000 / timecounter->frequency; 185 error = copyout(&ts, SCARG(uap, tp), sizeof(ts)); 186 } 187 return (error); 188} 189 190static int nanowait; 191 192static int 193nanosleep1(p, rqt, rmt) 194 struct proc *p; 195 struct timespec *rqt, *rmt; 196{ 197 struct timespec ts, ts2, ts3; 198 struct timeval tv; 199 int error; 200 201 if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000) 202 return (EINVAL); 203 if (rqt->tv_sec < 0 || rqt->tv_sec == 0 && rqt->tv_nsec == 0) 204 return (0); 205 getnanouptime(&ts); 206 timespecadd(&ts, rqt); 207 TIMESPEC_TO_TIMEVAL(&tv, rqt); 208 for (;;) { 209 error = tsleep(&nanowait, PWAIT | PCATCH, "nanslp", 210 tvtohz(&tv)); 211 getnanouptime(&ts2); 212 if (error != EWOULDBLOCK) { 213 if (error == ERESTART) 214 error = EINTR; 215 if (rmt != NULL) { 216 timespecsub(&ts, &ts2); 217 if (ts.tv_sec < 0) 218 timespecclear(&ts); 219 *rmt = ts; 220 } 221 return (error); 222 } 223 if (timespeccmp(&ts2, &ts, >=)) 224 return (0); 225 ts3 = ts; 226 timespecsub(&ts3, &ts2); 227 TIMESPEC_TO_TIMEVAL(&tv, &ts3); 228 } 229} 230 231#ifndef _SYS_SYSPROTO_H_ 232struct nanosleep_args { 233 struct timespec *rqtp; 234 struct timespec *rmtp; 235}; 236#endif 237 238/* ARGSUSED */ 239int 240nanosleep(p, uap) 241 struct proc *p; 242 struct nanosleep_args *uap; 243{ 244 struct timespec rmt, rqt; 245 int error, error2; 246 247 error = copyin(SCARG(uap, rqtp), &rqt, sizeof(rqt)); 248 if (error) 249 return (error); 250 if (SCARG(uap, rmtp)) 251 if (!useracc((caddr_t)SCARG(uap, rmtp), sizeof(rmt), B_WRITE)) 252 return (EFAULT); 253 error = nanosleep1(p, &rqt, &rmt); 254 if (error && SCARG(uap, rmtp)) { 255 error2 = copyout(&rmt, SCARG(uap, rmtp), sizeof(rmt)); 256 if (error2) /* XXX shouldn't happen, did useracc() above */ 257 return (error2); 258 } 259 return (error); 260} 261 262#ifndef _SYS_SYSPROTO_H_ 263struct gettimeofday_args { 264 struct timeval *tp; 265 struct timezone *tzp; 266}; 267#endif 268/* ARGSUSED */ 269int 270gettimeofday(p, uap) 271 struct proc *p; 272 register struct gettimeofday_args *uap; 273{ 274 struct timeval atv; 275 int error = 0; 276 277 if (uap->tp) { 278 microtime(&atv); 279 if ((error = copyout((caddr_t)&atv, (caddr_t)uap->tp, 280 sizeof (atv)))) 281 return (error); 282 } 283 if (uap->tzp) 284 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, 285 sizeof (tz)); 286 return (error); 287} 288 289#ifndef _SYS_SYSPROTO_H_ 290struct settimeofday_args { 291 struct timeval *tv; 292 struct timezone *tzp; 293}; 294#endif 295/* ARGSUSED */ 296int 297settimeofday(p, uap) 298 struct proc *p; 299 struct settimeofday_args *uap; 300{ 301 struct timeval atv; 302 struct timezone atz; 303 int error; 304 305 if ((error = suser(p->p_ucred, &p->p_acflag))) 306 return (error); 307 /* Verify all parameters before changing time. */ 308 if (uap->tv) { 309 if ((error = copyin((caddr_t)uap->tv, (caddr_t)&atv, 310 sizeof(atv)))) 311 return (error); 312 if (atv.tv_usec < 0 || atv.tv_usec >= 1000000) 313 return (EINVAL); 314 } 315 if (uap->tzp && 316 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz)))) 317 return (error); 318 if (uap->tv && (error = settime(&atv))) 319 return (error); 320 if (uap->tzp) 321 tz = atz; 322 return (0); 323} 324 325int tickdelta; /* current clock skew, us. per tick */ 326long timedelta; /* unapplied time correction, us. */ 327static long bigadj = 1000000; /* use 10x skew above bigadj us. */ 328 329#ifndef _SYS_SYSPROTO_H_ 330struct adjtime_args { 331 struct timeval *delta; 332 struct timeval *olddelta; 333}; 334#endif 335/* ARGSUSED */ 336int 337adjtime(p, uap) 338 struct proc *p; 339 register struct adjtime_args *uap; 340{ 341 struct timeval atv; 342 register long ndelta, ntickdelta, odelta; 343 int s, error; 344 345 if ((error = suser(p->p_ucred, &p->p_acflag))) 346 return (error); 347 if ((error = 348 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval)))) 349 return (error); 350 351 /* 352 * Compute the total correction and the rate at which to apply it. 353 * Round the adjustment down to a whole multiple of the per-tick 354 * delta, so that after some number of incremental changes in 355 * hardclock(), tickdelta will become zero, lest the correction 356 * overshoot and start taking us away from the desired final time. 357 */ 358 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 359 if (ndelta > bigadj || ndelta < -bigadj) 360 ntickdelta = 10 * tickadj; 361 else 362 ntickdelta = tickadj; 363 if (ndelta % ntickdelta) 364 ndelta = ndelta / ntickdelta * ntickdelta; 365 366 /* 367 * To make hardclock()'s job easier, make the per-tick delta negative 368 * if we want time to run slower; then hardclock can simply compute 369 * tick + tickdelta, and subtract tickdelta from timedelta. 370 */ 371 if (ndelta < 0) 372 ntickdelta = -ntickdelta; 373 s = splclock(); 374 odelta = timedelta; 375 timedelta = ndelta; 376 tickdelta = ntickdelta; 377 splx(s); 378 379 if (uap->olddelta) { 380 atv.tv_sec = odelta / 1000000; 381 atv.tv_usec = odelta % 1000000; 382 (void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta, 383 sizeof(struct timeval)); 384 } 385 return (0); 386} 387 388/* 389 * Get value of an interval timer. The process virtual and 390 * profiling virtual time timers are kept in the p_stats area, since 391 * they can be swapped out. These are kept internally in the 392 * way they are specified externally: in time until they expire. 393 * 394 * The real time interval timer is kept in the process table slot 395 * for the process, and its value (it_value) is kept as an 396 * absolute time rather than as a delta, so that it is easy to keep 397 * periodic real-time signals from drifting. 398 * 399 * Virtual time timers are processed in the hardclock() routine of 400 * kern_clock.c. The real time timer is processed by a timeout 401 * routine, called from the softclock() routine. Since a callout 402 * may be delayed in real time due to interrupt processing in the system, 403 * it is possible for the real time timeout routine (realitexpire, given below), 404 * to be delayed in real time past when it is supposed to occur. It 405 * does not suffice, therefore, to reload the real timer .it_value from the 406 * real time timers .it_interval. Rather, we compute the next time in 407 * absolute time the timer should go off. 408 */ 409#ifndef _SYS_SYSPROTO_H_ 410struct getitimer_args { 411 u_int which; 412 struct itimerval *itv; 413}; 414#endif 415/* ARGSUSED */ 416int 417getitimer(p, uap) 418 struct proc *p; 419 register struct getitimer_args *uap; 420{ 421 struct timeval ctv; 422 struct itimerval aitv; 423 int s; 424 425 if (uap->which > ITIMER_PROF) 426 return (EINVAL); 427 s = splclock(); /* XXX still needed ? */ 428 if (uap->which == ITIMER_REAL) { 429 /* 430 * Convert from absoulte to relative time in .it_value 431 * part of real time timer. If time for real time timer 432 * has passed return 0, else return difference between 433 * current time and time for the timer to go off. 434 */ 435 aitv = p->p_realtimer; 436 if (timevalisset(&aitv.it_value)) { 437 getmicrouptime(&ctv); 438 if (timevalcmp(&aitv.it_value, &ctv, <)) 439 timevalclear(&aitv.it_value); 440 else 441 timevalsub(&aitv.it_value, &ctv); 442 } 443 } else 444 aitv = p->p_stats->p_timer[uap->which]; 445 splx(s); 446 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv, 447 sizeof (struct itimerval))); 448} 449 450#ifndef _SYS_SYSPROTO_H_ 451struct setitimer_args { 452 u_int which; 453 struct itimerval *itv, *oitv; 454}; 455#endif 456/* ARGSUSED */ 457int 458setitimer(p, uap) 459 struct proc *p; 460 register struct setitimer_args *uap; 461{ 462 struct itimerval aitv; 463 struct timeval ctv; 464 register struct itimerval *itvp; 465 int s, error; 466 467 if (uap->which > ITIMER_PROF) 468 return (EINVAL); 469 itvp = uap->itv; 470 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 471 sizeof(struct itimerval)))) 472 return (error); 473 if ((uap->itv = uap->oitv) && 474 (error = getitimer(p, (struct getitimer_args *)uap))) 475 return (error); 476 if (itvp == 0) 477 return (0); 478 if (itimerfix(&aitv.it_value)) 479 return (EINVAL); 480 if (!timevalisset(&aitv.it_value)) 481 timevalclear(&aitv.it_interval); 482 else if (itimerfix(&aitv.it_interval)) 483 return (EINVAL); 484 s = splclock(); /* XXX: still needed ? */ 485 if (uap->which == ITIMER_REAL) { 486 if (timevalisset(&p->p_realtimer.it_value)) 487 untimeout(realitexpire, (caddr_t)p, p->p_ithandle); 488 if (timevalisset(&aitv.it_value)) 489 p->p_ithandle = timeout(realitexpire, (caddr_t)p, 490 tvtohz(&aitv.it_value)); 491 getmicrouptime(&ctv); 492 timevaladd(&aitv.it_value, &ctv); 493 p->p_realtimer = aitv; 494 } else 495 p->p_stats->p_timer[uap->which] = aitv; 496 splx(s); 497 return (0); 498} 499 500/* 501 * Real interval timer expired: 502 * send process whose timer expired an alarm signal. 503 * If time is not set up to reload, then just return. 504 * Else compute next time timer should go off which is > current time. 505 * This is where delay in processing this timeout causes multiple 506 * SIGALRM calls to be compressed into one. 507 * tvtohz() always adds 1 to allow for the time until the next clock 508 * interrupt being strictly less than 1 clock tick, but we don't want 509 * that here since we want to appear to be in sync with the clock 510 * interrupt even when we're delayed. 511 */ 512void 513realitexpire(arg) 514 void *arg; 515{ 516 register struct proc *p; 517 struct timeval ctv, ntv; 518 int s; 519 520 p = (struct proc *)arg; 521 psignal(p, SIGALRM); 522 if (!timevalisset(&p->p_realtimer.it_interval)) { 523 timevalclear(&p->p_realtimer.it_value); 524 return; 525 } 526 for (;;) { 527 s = splclock(); /* XXX: still neeeded ? */ 528 timevaladd(&p->p_realtimer.it_value, 529 &p->p_realtimer.it_interval); 530 getmicrouptime(&ctv); 531 if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) { 532 ntv = p->p_realtimer.it_value; 533 timevalsub(&ntv, &ctv); 534 p->p_ithandle = 535 timeout(realitexpire, (caddr_t)p, tvtohz(&ntv)); 536 splx(s); 537 return; 538 } 539 splx(s); 540 } 541} 542 543/* 544 * Check that a proposed value to load into the .it_value or 545 * .it_interval part of an interval timer is acceptable, and 546 * fix it to have at least minimal value (i.e. if it is less 547 * than the resolution of the clock, round it up.) 548 */ 549int 550itimerfix(tv) 551 struct timeval *tv; 552{ 553 554 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 555 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 556 return (EINVAL); 557 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 558 tv->tv_usec = tick; 559 return (0); 560} 561 562/* 563 * Decrement an interval timer by a specified number 564 * of microseconds, which must be less than a second, 565 * i.e. < 1000000. If the timer expires, then reload 566 * it. In this case, carry over (usec - old value) to 567 * reduce the value reloaded into the timer so that 568 * the timer does not drift. This routine assumes 569 * that it is called in a context where the timers 570 * on which it is operating cannot change in value. 571 */ 572int 573itimerdecr(itp, usec) 574 register struct itimerval *itp; 575 int usec; 576{ 577 578 if (itp->it_value.tv_usec < usec) { 579 if (itp->it_value.tv_sec == 0) { 580 /* expired, and already in next interval */ 581 usec -= itp->it_value.tv_usec; 582 goto expire; 583 } 584 itp->it_value.tv_usec += 1000000; 585 itp->it_value.tv_sec--; 586 } 587 itp->it_value.tv_usec -= usec; 588 usec = 0; 589 if (timevalisset(&itp->it_value)) 590 return (1); 591 /* expired, exactly at end of interval */ 592expire: 593 if (timevalisset(&itp->it_interval)) { 594 itp->it_value = itp->it_interval; 595 itp->it_value.tv_usec -= usec; 596 if (itp->it_value.tv_usec < 0) { 597 itp->it_value.tv_usec += 1000000; 598 itp->it_value.tv_sec--; 599 } 600 } else 601 itp->it_value.tv_usec = 0; /* sec is already 0 */ 602 return (0); 603} 604 605/* 606 * Add and subtract routines for timevals. 607 * N.B.: subtract routine doesn't deal with 608 * results which are before the beginning, 609 * it just gets very confused in this case. 610 * Caveat emptor. 611 */ 612void 613timevaladd(t1, t2) 614 struct timeval *t1, *t2; 615{ 616 617 t1->tv_sec += t2->tv_sec; 618 t1->tv_usec += t2->tv_usec; 619 timevalfix(t1); 620} 621 622void 623timevalsub(t1, t2) 624 struct timeval *t1, *t2; 625{ 626 627 t1->tv_sec -= t2->tv_sec; 628 t1->tv_usec -= t2->tv_usec; 629 timevalfix(t1); 630} 631 632static void 633timevalfix(t1) 634 struct timeval *t1; 635{ 636 637 if (t1->tv_usec < 0) { 638 t1->tv_sec--; 639 t1->tv_usec += 1000000; 640 } 641 if (t1->tv_usec >= 1000000) { 642 t1->tv_sec++; 643 t1->tv_usec -= 1000000; 644 } 645} 646