kern_time.c revision 40648
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 1.58 1998/06/09 13:10:53 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 int s; 83 84 s = splclock(); 85 microtime(&tv1); 86 delta = *tv; 87 timevalsub(&delta, &tv1); 88 89 /* 90 * If the system is secure, we do not allow the time to be 91 * set to an earlier value (it may be slowed using adjtime, 92 * but not set back). This feature prevent interlopers from 93 * setting arbitrary time stamps on files. 94 */ 95 if (delta.tv_sec < 0 && securelevel > 1) { 96 splx(s); 97 return (EPERM); 98 } 99 100 ts.tv_sec = tv->tv_sec; 101 ts.tv_nsec = tv->tv_usec * 1000; 102 set_timecounter(&ts); 103 (void) splsoftclock(); 104 lease_updatetime(delta.tv_sec); 105 splx(s); 106 resettodr(); 107 return (0); 108} 109 110#ifndef _SYS_SYSPROTO_H_ 111struct clock_gettime_args { 112 clockid_t clock_id; 113 struct timespec *tp; 114}; 115#endif 116 117/* ARGSUSED */ 118int 119clock_gettime(p, uap) 120 struct proc *p; 121 struct clock_gettime_args *uap; 122{ 123 struct timespec ats; 124 125 if (SCARG(uap, clock_id) != CLOCK_REALTIME) 126 return (EINVAL); 127 nanotime(&ats); 128 return (copyout(&ats, SCARG(uap, tp), sizeof(ats))); 129} 130 131#ifndef _SYS_SYSPROTO_H_ 132struct clock_settime_args { 133 clockid_t clock_id; 134 const struct timespec *tp; 135}; 136#endif 137 138/* ARGSUSED */ 139int 140clock_settime(p, uap) 141 struct proc *p; 142 struct clock_settime_args *uap; 143{ 144 struct timeval atv; 145 struct timespec ats; 146 int error; 147 148 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 149 return (error); 150 if (SCARG(uap, clock_id) != CLOCK_REALTIME) 151 return (EINVAL); 152 if ((error = copyin(SCARG(uap, tp), &ats, sizeof(ats))) != 0) 153 return (error); 154 if (ats.tv_nsec < 0 || ats.tv_nsec >= 1000000000) 155 return (EINVAL); 156 /* XXX Don't convert nsec->usec and back */ 157 TIMESPEC_TO_TIMEVAL(&atv, &ats); 158 if ((error = settime(&atv))) 159 return (error); 160 return (0); 161} 162 163#ifndef _SYS_SYSPROTO_H_ 164struct clock_getres_args { 165 clockid_t clock_id; 166 struct timespec *tp; 167}; 168#endif 169 170int 171clock_getres(p, uap) 172 struct proc *p; 173 struct clock_getres_args *uap; 174{ 175 struct timespec ts; 176 int error; 177 178 if (SCARG(uap, clock_id) != CLOCK_REALTIME) 179 return (EINVAL); 180 error = 0; 181 if (SCARG(uap, tp)) { 182 ts.tv_sec = 0; 183 ts.tv_nsec = 1000000000 / timecounter->tc_frequency; 184 error = copyout(&ts, SCARG(uap, tp), sizeof(ts)); 185 } 186 return (error); 187} 188 189static int nanowait; 190 191static int 192nanosleep1(p, rqt, rmt) 193 struct proc *p; 194 struct timespec *rqt, *rmt; 195{ 196 struct timespec ts, ts2, ts3; 197 struct timeval tv; 198 int error; 199 200 if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000) 201 return (EINVAL); 202 if (rqt->tv_sec < 0 || rqt->tv_sec == 0 && rqt->tv_nsec == 0) 203 return (0); 204 getnanouptime(&ts); 205 timespecadd(&ts, rqt); 206 TIMESPEC_TO_TIMEVAL(&tv, rqt); 207 for (;;) { 208 error = tsleep(&nanowait, PWAIT | PCATCH, "nanslp", 209 tvtohz(&tv)); 210 getnanouptime(&ts2); 211 if (error != EWOULDBLOCK) { 212 if (error == ERESTART) 213 error = EINTR; 214 if (rmt != NULL) { 215 timespecsub(&ts, &ts2); 216 if (ts.tv_sec < 0) 217 timespecclear(&ts); 218 *rmt = ts; 219 } 220 return (error); 221 } 222 if (timespeccmp(&ts2, &ts, >=)) 223 return (0); 224 ts3 = ts; 225 timespecsub(&ts3, &ts2); 226 TIMESPEC_TO_TIMEVAL(&tv, &ts3); 227 } 228} 229 230#ifndef _SYS_SYSPROTO_H_ 231struct nanosleep_args { 232 struct timespec *rqtp; 233 struct timespec *rmtp; 234}; 235#endif 236 237/* ARGSUSED */ 238int 239nanosleep(p, uap) 240 struct proc *p; 241 struct nanosleep_args *uap; 242{ 243 struct timespec rmt, rqt; 244 int error, error2; 245 246 error = copyin(SCARG(uap, rqtp), &rqt, sizeof(rqt)); 247 if (error) 248 return (error); 249 if (SCARG(uap, rmtp)) 250 if (!useracc((caddr_t)SCARG(uap, rmtp), sizeof(rmt), B_WRITE)) 251 return (EFAULT); 252 error = nanosleep1(p, &rqt, &rmt); 253 if (error && SCARG(uap, rmtp)) { 254 error2 = copyout(&rmt, SCARG(uap, rmtp), sizeof(rmt)); 255 if (error2) /* XXX shouldn't happen, did useracc() above */ 256 return (error2); 257 } 258 return (error); 259} 260 261#ifndef _SYS_SYSPROTO_H_ 262struct gettimeofday_args { 263 struct timeval *tp; 264 struct timezone *tzp; 265}; 266#endif 267/* ARGSUSED */ 268int 269gettimeofday(p, uap) 270 struct proc *p; 271 register struct gettimeofday_args *uap; 272{ 273 struct timeval atv; 274 int error = 0; 275 276 if (uap->tp) { 277 microtime(&atv); 278 if ((error = copyout((caddr_t)&atv, (caddr_t)uap->tp, 279 sizeof (atv)))) 280 return (error); 281 } 282 if (uap->tzp) 283 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, 284 sizeof (tz)); 285 return (error); 286} 287 288#ifndef _SYS_SYSPROTO_H_ 289struct settimeofday_args { 290 struct timeval *tv; 291 struct timezone *tzp; 292}; 293#endif 294/* ARGSUSED */ 295int 296settimeofday(p, uap) 297 struct proc *p; 298 struct settimeofday_args *uap; 299{ 300 struct timeval atv; 301 struct timezone atz; 302 int error; 303 304 if ((error = suser(p->p_ucred, &p->p_acflag))) 305 return (error); 306 /* Verify all parameters before changing time. */ 307 if (uap->tv) { 308 if ((error = copyin((caddr_t)uap->tv, (caddr_t)&atv, 309 sizeof(atv)))) 310 return (error); 311 if (atv.tv_usec < 0 || atv.tv_usec >= 1000000) 312 return (EINVAL); 313 } 314 if (uap->tzp && 315 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz)))) 316 return (error); 317 if (uap->tv && (error = settime(&atv))) 318 return (error); 319 if (uap->tzp) 320 tz = atz; 321 return (0); 322} 323 324int tickdelta; /* current clock skew, us. per tick */ 325long timedelta; /* unapplied time correction, us. */ 326static long bigadj = 1000000; /* use 10x skew above bigadj us. */ 327 328#ifndef _SYS_SYSPROTO_H_ 329struct adjtime_args { 330 struct timeval *delta; 331 struct timeval *olddelta; 332}; 333#endif 334/* ARGSUSED */ 335int 336adjtime(p, uap) 337 struct proc *p; 338 register struct adjtime_args *uap; 339{ 340 struct timeval atv; 341 register long ndelta, ntickdelta, odelta; 342 int s, error; 343 344 if ((error = suser(p->p_ucred, &p->p_acflag))) 345 return (error); 346 if ((error = 347 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval)))) 348 return (error); 349 350 /* 351 * Compute the total correction and the rate at which to apply it. 352 * Round the adjustment down to a whole multiple of the per-tick 353 * delta, so that after some number of incremental changes in 354 * hardclock(), tickdelta will become zero, lest the correction 355 * overshoot and start taking us away from the desired final time. 356 */ 357 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 358 if (ndelta > bigadj || ndelta < -bigadj) 359 ntickdelta = 10 * tickadj; 360 else 361 ntickdelta = tickadj; 362 if (ndelta % ntickdelta) 363 ndelta = ndelta / ntickdelta * ntickdelta; 364 365 /* 366 * To make hardclock()'s job easier, make the per-tick delta negative 367 * if we want time to run slower; then hardclock can simply compute 368 * tick + tickdelta, and subtract tickdelta from timedelta. 369 */ 370 if (ndelta < 0) 371 ntickdelta = -ntickdelta; 372 s = splclock(); 373 odelta = timedelta; 374 timedelta = ndelta; 375 tickdelta = ntickdelta; 376 splx(s); 377 378 if (uap->olddelta) { 379 atv.tv_sec = odelta / 1000000; 380 atv.tv_usec = odelta % 1000000; 381 (void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta, 382 sizeof(struct timeval)); 383 } 384 return (0); 385} 386 387/* 388 * Get value of an interval timer. The process virtual and 389 * profiling virtual time timers are kept in the p_stats area, since 390 * they can be swapped out. These are kept internally in the 391 * way they are specified externally: in time until they expire. 392 * 393 * The real time interval timer is kept in the process table slot 394 * for the process, and its value (it_value) is kept as an 395 * absolute time rather than as a delta, so that it is easy to keep 396 * periodic real-time signals from drifting. 397 * 398 * Virtual time timers are processed in the hardclock() routine of 399 * kern_clock.c. The real time timer is processed by a timeout 400 * routine, called from the softclock() routine. Since a callout 401 * may be delayed in real time due to interrupt processing in the system, 402 * it is possible for the real time timeout routine (realitexpire, given below), 403 * to be delayed in real time past when it is supposed to occur. It 404 * does not suffice, therefore, to reload the real timer .it_value from the 405 * real time timers .it_interval. Rather, we compute the next time in 406 * absolute time the timer should go off. 407 */ 408#ifndef _SYS_SYSPROTO_H_ 409struct getitimer_args { 410 u_int which; 411 struct itimerval *itv; 412}; 413#endif 414/* ARGSUSED */ 415int 416getitimer(p, uap) 417 struct proc *p; 418 register struct getitimer_args *uap; 419{ 420 struct timeval ctv; 421 struct itimerval aitv; 422 int s; 423 424 if (uap->which > ITIMER_PROF) 425 return (EINVAL); 426 s = splclock(); /* XXX still needed ? */ 427 if (uap->which == ITIMER_REAL) { 428 /* 429 * Convert from absolute to relative time in .it_value 430 * part of real time timer. If time for real time timer 431 * has passed return 0, else return difference between 432 * current time and time for the timer to go off. 433 */ 434 aitv = p->p_realtimer; 435 if (timevalisset(&aitv.it_value)) { 436 getmicrouptime(&ctv); 437 if (timevalcmp(&aitv.it_value, &ctv, <)) 438 timevalclear(&aitv.it_value); 439 else 440 timevalsub(&aitv.it_value, &ctv); 441 } 442 } else 443 aitv = p->p_stats->p_timer[uap->which]; 444 splx(s); 445 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv, 446 sizeof (struct itimerval))); 447} 448 449#ifndef _SYS_SYSPROTO_H_ 450struct setitimer_args { 451 u_int which; 452 struct itimerval *itv, *oitv; 453}; 454#endif 455/* ARGSUSED */ 456int 457setitimer(p, uap) 458 struct proc *p; 459 register struct setitimer_args *uap; 460{ 461 struct itimerval aitv; 462 struct timeval ctv; 463 register struct itimerval *itvp; 464 int s, error; 465 466 if (uap->which > ITIMER_PROF) 467 return (EINVAL); 468 itvp = uap->itv; 469 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 470 sizeof(struct itimerval)))) 471 return (error); 472 if ((uap->itv = uap->oitv) && 473 (error = getitimer(p, (struct getitimer_args *)uap))) 474 return (error); 475 if (itvp == 0) 476 return (0); 477 if (itimerfix(&aitv.it_value)) 478 return (EINVAL); 479 if (!timevalisset(&aitv.it_value)) 480 timevalclear(&aitv.it_interval); 481 else if (itimerfix(&aitv.it_interval)) 482 return (EINVAL); 483 s = splclock(); /* XXX: still needed ? */ 484 if (uap->which == ITIMER_REAL) { 485 if (timevalisset(&p->p_realtimer.it_value)) 486 untimeout(realitexpire, (caddr_t)p, p->p_ithandle); 487 if (timevalisset(&aitv.it_value)) 488 p->p_ithandle = timeout(realitexpire, (caddr_t)p, 489 tvtohz(&aitv.it_value)); 490 getmicrouptime(&ctv); 491 timevaladd(&aitv.it_value, &ctv); 492 p->p_realtimer = aitv; 493 } else 494 p->p_stats->p_timer[uap->which] = aitv; 495 splx(s); 496 return (0); 497} 498 499/* 500 * Real interval timer expired: 501 * send process whose timer expired an alarm signal. 502 * If time is not set up to reload, then just return. 503 * Else compute next time timer should go off which is > current time. 504 * This is where delay in processing this timeout causes multiple 505 * SIGALRM calls to be compressed into one. 506 * tvtohz() always adds 1 to allow for the time until the next clock 507 * interrupt being strictly less than 1 clock tick, but we don't want 508 * that here since we want to appear to be in sync with the clock 509 * interrupt even when we're delayed. 510 */ 511void 512realitexpire(arg) 513 void *arg; 514{ 515 register struct proc *p; 516 struct timeval ctv, ntv; 517 int s; 518 519 p = (struct proc *)arg; 520 psignal(p, SIGALRM); 521 if (!timevalisset(&p->p_realtimer.it_interval)) { 522 timevalclear(&p->p_realtimer.it_value); 523 return; 524 } 525 for (;;) { 526 s = splclock(); /* XXX: still neeeded ? */ 527 timevaladd(&p->p_realtimer.it_value, 528 &p->p_realtimer.it_interval); 529 getmicrouptime(&ctv); 530 if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) { 531 ntv = p->p_realtimer.it_value; 532 timevalsub(&ntv, &ctv); 533 p->p_ithandle = timeout(realitexpire, (caddr_t)p, 534 tvtohz(&ntv) - 1); 535 splx(s); 536 return; 537 } 538 splx(s); 539 } 540} 541 542/* 543 * Check that a proposed value to load into the .it_value or 544 * .it_interval part of an interval timer is acceptable, and 545 * fix it to have at least minimal value (i.e. if it is less 546 * than the resolution of the clock, round it up.) 547 */ 548int 549itimerfix(tv) 550 struct timeval *tv; 551{ 552 553 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 554 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 555 return (EINVAL); 556 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 557 tv->tv_usec = tick; 558 return (0); 559} 560 561/* 562 * Decrement an interval timer by a specified number 563 * of microseconds, which must be less than a second, 564 * i.e. < 1000000. If the timer expires, then reload 565 * it. In this case, carry over (usec - old value) to 566 * reduce the value reloaded into the timer so that 567 * the timer does not drift. This routine assumes 568 * that it is called in a context where the timers 569 * on which it is operating cannot change in value. 570 */ 571int 572itimerdecr(itp, usec) 573 register struct itimerval *itp; 574 int usec; 575{ 576 577 if (itp->it_value.tv_usec < usec) { 578 if (itp->it_value.tv_sec == 0) { 579 /* expired, and already in next interval */ 580 usec -= itp->it_value.tv_usec; 581 goto expire; 582 } 583 itp->it_value.tv_usec += 1000000; 584 itp->it_value.tv_sec--; 585 } 586 itp->it_value.tv_usec -= usec; 587 usec = 0; 588 if (timevalisset(&itp->it_value)) 589 return (1); 590 /* expired, exactly at end of interval */ 591expire: 592 if (timevalisset(&itp->it_interval)) { 593 itp->it_value = itp->it_interval; 594 itp->it_value.tv_usec -= usec; 595 if (itp->it_value.tv_usec < 0) { 596 itp->it_value.tv_usec += 1000000; 597 itp->it_value.tv_sec--; 598 } 599 } else 600 itp->it_value.tv_usec = 0; /* sec is already 0 */ 601 return (0); 602} 603 604/* 605 * Add and subtract routines for timevals. 606 * N.B.: subtract routine doesn't deal with 607 * results which are before the beginning, 608 * it just gets very confused in this case. 609 * Caveat emptor. 610 */ 611void 612timevaladd(t1, t2) 613 struct timeval *t1, *t2; 614{ 615 616 t1->tv_sec += t2->tv_sec; 617 t1->tv_usec += t2->tv_usec; 618 timevalfix(t1); 619} 620 621void 622timevalsub(t1, t2) 623 struct timeval *t1, *t2; 624{ 625 626 t1->tv_sec -= t2->tv_sec; 627 t1->tv_usec -= t2->tv_usec; 628 timevalfix(t1); 629} 630 631static void 632timevalfix(t1) 633 struct timeval *t1; 634{ 635 636 if (t1->tv_usec < 0) { 637 t1->tv_sec--; 638 t1->tv_usec += 1000000; 639 } 640 if (t1->tv_usec >= 1000000) { 641 t1->tv_sec++; 642 t1->tv_usec -= 1000000; 643 } 644} 645