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 1.34 1997/09/02 20:05:49 bde 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 50 struct 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 62 static int nanosleep1 __P((struct proc *p, struct timespec *rqt, 63 struct timespec *rmt)); 64 static int settime __P((struct timeval *)); 65 static void timevalfix __P((struct timeval *)); 66 67 static int 68 settime(tv) 69 struct timeval *tv; 70 { 71 struct timeval delta; 72 struct proc *p; 73 int s; 74 75 /* 76 * Must not set clock backwards in highly secure mode. 77 */ 78 s = splclock(); 79 delta.tv_sec = tv->tv_sec - time.tv_sec; 80 delta.tv_usec = tv->tv_usec - time.tv_usec; 81 splx(s); 82 timevalfix(&delta); 83 if (delta.tv_sec < 0 && securelevel > 1) 84 return (EPERM); 85 86 s = splclock(); 87 /* 88 * Recalculate delta directly to minimize clock interrupt 89 * latency. Fix it after the ipl has been lowered. 90 */ 91 delta.tv_sec = tv->tv_sec - time.tv_sec; 92 delta.tv_usec = tv->tv_usec - time.tv_usec; 93 time = *tv; 94 /* 95 * XXX should arrange for microtime() to agree with *tv if 96 * it is called now. As it is, it may add up to about 97 * `tick' unwanted usec. 98 * Another problem is that clock interrupts may occur at 99 * other than multiples of `tick'. It's not worth fixing 100 * this here, since the problem is also caused by tick 101 * adjustments. 102 */ 103 (void) splsoftclock(); 104 timevalfix(&delta); 105 timevaladd(&boottime, &delta); 106 timevaladd(&runtime, &delta); 107 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 108 if (timerisset(&p->p_realtimer.it_value)) 109 timevaladd(&p->p_realtimer.it_value, &delta); 110 if (p->p_sleepend) 111 timevaladd(p->p_sleepend, &delta); 112 } 113 #ifdef NFS 114 lease_updatetime(delta.tv_sec); 115 #endif 116 splx(s); 117 resettodr(); 118 return (0); 119 } 120 121 #ifndef _SYS_SYSPROTO_H_ 122 struct clock_gettime_args { 123 clockid_t clock_id; 124 struct timespec *tp; 125 }; 126 #endif 127 128 /* ARGSUSED */ 129 int 130 clock_gettime(p, uap, retval) 131 struct proc *p; 132 struct clock_gettime_args *uap; 133 register_t *retval; 134 { 135 struct timeval atv; 136 struct timespec ats; 137 138 if (SCARG(uap, clock_id) != CLOCK_REALTIME) 139 return (EINVAL); 140 microtime(&atv); 141 TIMEVAL_TO_TIMESPEC(&atv, &ats); 142 return (copyout(&ats, SCARG(uap, tp), sizeof(ats))); 143 } 144 145 #ifndef _SYS_SYSPROTO_H_ 146 struct clock_settime_args { 147 clockid_t clock_id; 148 const struct timespec *tp; 149 }; 150 #endif 151 152 /* ARGSUSED */ 153 int 154 clock_settime(p, uap, retval) 155 struct proc *p; 156 struct clock_settime_args *uap; 157 register_t *retval; 158 { 159 struct timeval atv; 160 struct timespec ats; 161 int error; 162 163 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 164 return (error); 165 if (SCARG(uap, clock_id) != CLOCK_REALTIME) 166 return (EINVAL); 167 if ((error = copyin(SCARG(uap, tp), &ats, sizeof(ats))) != 0) 168 return (error); 169 if (ats.tv_nsec < 0 || ats.tv_nsec >= 1000000000) 170 return (EINVAL); 171 TIMESPEC_TO_TIMEVAL(&atv, &ats); 172 if ((error = settime(&atv))) 173 return (error); 174 return (0); 175 } 176 177 #ifndef _SYS_SYSPROTO_H_ 178 struct clock_getres_args { 179 clockid_t clock_id; 180 struct timespec *tp; 181 }; 182 #endif 183 184 int 185 clock_getres(p, uap, retval) 186 struct proc *p; 187 struct clock_getres_args *uap; 188 register_t *retval; 189 { 190 struct timespec ts; 191 int error; 192 193 if (SCARG(uap, clock_id) != CLOCK_REALTIME) 194 return (EINVAL); 195 error = 0; 196 if (SCARG(uap, tp)) { 197 ts.tv_sec = 0; 198 ts.tv_nsec = 1000000000 / hz; 199 error = copyout(&ts, SCARG(uap, tp), sizeof(ts)); 200 } 201 return (error); 202 } 203 204 static int nanowait; 205 206 static int 207 nanosleep1(p, rqt, rmt) 208 struct proc *p; 209 struct timespec *rqt, *rmt; 210 { 211 struct timeval atv, utv, rtv; 212 int error, s, timo, i, n; 213 214 if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000) 215 return (EINVAL); 216 if (rqt->tv_sec < 0 || rqt->tv_sec == 0 && rqt->tv_nsec == 0) 217 return (0); 218 TIMESPEC_TO_TIMEVAL(&atv, rqt) 219 220 if (itimerfix(&atv)) { 221 n = atv.tv_sec / 100000000; 222 rtv = atv; 223 rtv.tv_sec %= 100000000; 224 (void)itimerfix(&rtv); 225 } else 226 n = 0; 227 228 for (i = 0, error = EWOULDBLOCK; i <= n && error == EWOULDBLOCK; i++) { 229 if (n > 0) { 230 if (i == n) 231 atv = rtv; 232 else { 233 atv.tv_sec = 100000000; 234 atv.tv_usec = 0; 235 } 236 } 237 /* 238 * XXX this is not as careful as settimeofday() about minimising 239 * interrupt latency. The hzto() interface is inconvenient as usual. 240 */ 241 s = splclock(); 242 timevaladd(&atv, &time); 243 timo = hzto(&atv); 244 splx(s); 245 246 p->p_sleepend = &atv; 247 error = tsleep(&nanowait, PWAIT | PCATCH, "nanslp", timo); 248 p->p_sleepend = NULL; 249 if (error == ERESTART) 250 error = EINTR; 251 if (rmt != NULL && (i == n || error != EWOULDBLOCK)) { 252 /*- 253 * XXX this is unnecessary and possibly wrong if the timeout 254 * expired. Then the remaining time should be zero. If the 255 * calculation gives a nonzero value, then we have a bug. 256 * (1) if settimeofday() was called, then the calculation is 257 * probably wrong, since `time' has probably become 258 * inconsistent with the ending time `atv'. 259 * XXX (1) should be fixed now with p->p_sleepend; 260 * (2) otherwise, our calculation of `timo' was wrong, perhaps 261 * due to `tick' being wrong when hzto() was called or 262 * changing afterwards (it can be wrong or change due to 263 * hzto() not knowing about adjtime(2) or tickadj(8)). 264 * Then we should be sleeping again instead instead of 265 * returning. Rounding up in hzto() probably fixes this 266 * problem for small timeouts, but the absolute error may 267 * be large for large timeouts. 268 */ 269 s = splclock(); 270 utv = time; 271 splx(s); 272 timevalsub(&atv, &utv); 273 if (atv.tv_sec < 0) 274 timerclear(&atv); 275 if (n > 0) 276 atv.tv_sec += (n - i) * 100000000; 277 TIMEVAL_TO_TIMESPEC(&atv, rmt); 278 } 279 } 280 return (error == EWOULDBLOCK ? 0 : error); 281 } 282 283 #ifndef _SYS_SYSPROTO_H_ 284 struct nanosleep_args { 285 struct timespec *rqtp; 286 struct timespec *rmtp; 287 }; 288 #endif 289 290 /* ARGSUSED */ 291 int 292 nanosleep(p, uap, retval) 293 struct proc *p; 294 struct nanosleep_args *uap; 295 register_t *retval; 296 { 297 struct timespec rmt, rqt; 298 int error, error2; 299 300 error = copyin(SCARG(uap, rqtp), &rqt, sizeof(rqt)); 301 if (error) 302 return (error); 303 if (SCARG(uap, rmtp)) 304 if (!useracc((caddr_t)SCARG(uap, rmtp), sizeof(rmt), B_WRITE)) 305 return (EFAULT); 306 error = nanosleep1(p, &rqt, &rmt); 307 if (SCARG(uap, rmtp)) { 308 error2 = copyout(&rmt, SCARG(uap, rmtp), sizeof(rmt)); 309 if (error2) /* XXX shouldn't happen, did useracc() above */ 310 return (error2); 311 } 312 return (error); 313 } 314 315 #ifndef _SYS_SYSPROTO_H_ 316 struct signanosleep_args { 317 struct timespec *rqtp; 318 struct timespec *rmtp; 319 sigset_t *mask; 320 }; 321 #endif 322 323 /* ARGSUSED */ 324 int 325 signanosleep(p, uap, retval) 326 struct proc *p; 327 struct signanosleep_args *uap; 328 register_t *retval; 329 { 330 struct timespec rmt, rqt; 331 int error, error2; 332 struct sigacts *ps = p->p_sigacts; 333 sigset_t mask; 334 335 error = copyin(SCARG(uap, rqtp), &rqt, sizeof(rqt)); 336 if (error) 337 return (error); 338 if (SCARG(uap, rmtp)) 339 if (!useracc((caddr_t)SCARG(uap, rmtp), sizeof(rmt), B_WRITE)) 340 return (EFAULT); 341 error = copyin(SCARG(uap, mask), &mask, sizeof(mask)); 342 if (error) 343 return (error); 344 345 /* See kern_sig.c:sigsuspend() for explanation. */ 346 ps->ps_oldmask = p->p_sigmask; 347 ps->ps_flags |= SAS_OLDMASK; 348 p->p_sigmask = mask &~ sigcantmask; 349 350 error = nanosleep1(p, &rqt, &rmt); 351 352 /* See kern_sig.c:sigsuspend() again. */ 353 p->p_sigmask = ps->ps_oldmask; /* in case timeout rather than sig */ 354 ps->ps_flags &= ~SAS_OLDMASK; 355 356 if (SCARG(uap, rmtp)) { 357 error2 = copyout(&rmt, SCARG(uap, rmtp), sizeof(rmt)); 358 if (error2) /* XXX shouldn't happen, did useracc() above */ 359 return (error2); 360 } 361 return (error); 362 } 363 364 #ifndef _SYS_SYSPROTO_H_ 365 struct gettimeofday_args { 366 struct timeval *tp; 367 struct timezone *tzp; 368 }; 369 #endif 370 /* ARGSUSED */ 371 int 372 gettimeofday(p, uap, retval) 373 struct proc *p; 374 register struct gettimeofday_args *uap; 375 int *retval; 376 { 377 struct timeval atv; 378 int error = 0; 379 380 if (uap->tp) { 381 microtime(&atv); 382 if ((error = copyout((caddr_t)&atv, (caddr_t)uap->tp, 383 sizeof (atv)))) 384 return (error); 385 } 386 if (uap->tzp) 387 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, 388 sizeof (tz)); 389 return (error); 390 } 391 392 #ifndef _SYS_SYSPROTO_H_ 393 struct settimeofday_args { 394 struct timeval *tv; 395 struct timezone *tzp; 396 }; 397 #endif 398 /* ARGSUSED */ 399 int 400 settimeofday(p, uap, retval) 401 struct proc *p; 402 struct settimeofday_args *uap; 403 int *retval; 404 { 405 struct timeval atv; 406 struct timezone atz; 407 int error; 408 409 if ((error = suser(p->p_ucred, &p->p_acflag))) 410 return (error); 411 /* Verify all parameters before changing time. */ 412 if (uap->tv) { 413 if ((error = copyin((caddr_t)uap->tv, (caddr_t)&atv, 414 sizeof(atv)))) 415 return (error); 416 if (atv.tv_usec < 0 || atv.tv_usec >= 1000000) 417 return (EINVAL); 418 } 419 if (uap->tzp && 420 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz)))) 421 return (error); 422 if (uap->tv && (error = settime(&atv))) 423 return (error); 424 if (uap->tzp) 425 tz = atz; 426 return (0); 427 } 428 429 int tickdelta; /* current clock skew, us. per tick */ 430 long timedelta; /* unapplied time correction, us. */ 431 static long bigadj = 1000000; /* use 10x skew above bigadj us. */ 432 433 #ifndef _SYS_SYSPROTO_H_ 434 struct adjtime_args { 435 struct timeval *delta; 436 struct timeval *olddelta; 437 }; 438 #endif 439 /* ARGSUSED */ 440 int 441 adjtime(p, uap, retval) 442 struct proc *p; 443 register struct adjtime_args *uap; 444 int *retval; 445 { 446 struct timeval atv; 447 register long ndelta, ntickdelta, odelta; 448 int s, error; 449 450 if ((error = suser(p->p_ucred, &p->p_acflag))) 451 return (error); 452 if ((error = 453 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval)))) 454 return (error); 455 456 /* 457 * Compute the total correction and the rate at which to apply it. 458 * Round the adjustment down to a whole multiple of the per-tick 459 * delta, so that after some number of incremental changes in 460 * hardclock(), tickdelta will become zero, lest the correction 461 * overshoot and start taking us away from the desired final time. 462 */ 463 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 464 if (ndelta > bigadj || ndelta < -bigadj) 465 ntickdelta = 10 * tickadj; 466 else 467 ntickdelta = tickadj; 468 if (ndelta % ntickdelta) 469 ndelta = ndelta / ntickdelta * ntickdelta; 470 471 /* 472 * To make hardclock()'s job easier, make the per-tick delta negative 473 * if we want time to run slower; then hardclock can simply compute 474 * tick + tickdelta, and subtract tickdelta from timedelta. 475 */ 476 if (ndelta < 0) 477 ntickdelta = -ntickdelta; 478 s = splclock(); 479 odelta = timedelta; 480 timedelta = ndelta; 481 tickdelta = ntickdelta; 482 splx(s); 483 484 if (uap->olddelta) { 485 atv.tv_sec = odelta / 1000000; 486 atv.tv_usec = odelta % 1000000; 487 (void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta, 488 sizeof(struct timeval)); 489 } 490 return (0); 491 } 492 493 /* 494 * Get value of an interval timer. The process virtual and 495 * profiling virtual time timers are kept in the p_stats area, since 496 * they can be swapped out. These are kept internally in the 497 * way they are specified externally: in time until they expire. 498 * 499 * The real time interval timer is kept in the process table slot 500 * for the process, and its value (it_value) is kept as an 501 * absolute time rather than as a delta, so that it is easy to keep 502 * periodic real-time signals from drifting. 503 * 504 * Virtual time timers are processed in the hardclock() routine of 505 * kern_clock.c. The real time timer is processed by a timeout 506 * routine, called from the softclock() routine. Since a callout 507 * may be delayed in real time due to interrupt processing in the system, 508 * it is possible for the real time timeout routine (realitexpire, given below), 509 * to be delayed in real time past when it is supposed to occur. It 510 * does not suffice, therefore, to reload the real timer .it_value from the 511 * real time timers .it_interval. Rather, we compute the next time in 512 * absolute time the timer should go off. 513 */ 514 #ifndef _SYS_SYSPROTO_H_ 515 struct getitimer_args { 516 u_int which; 517 struct itimerval *itv; 518 }; 519 #endif 520 /* ARGSUSED */ 521 int 522 getitimer(p, uap, retval) 523 struct proc *p; 524 register struct getitimer_args *uap; 525 int *retval; 526 { 527 struct itimerval aitv; 528 int s; 529 530 if (uap->which > ITIMER_PROF) 531 return (EINVAL); 532 s = splclock(); 533 if (uap->which == ITIMER_REAL) { 534 /* 535 * Convert from absoulte to relative time in .it_value 536 * part of real time timer. If time for real time timer 537 * has passed return 0, else return difference between 538 * current time and time for the timer to go off. 539 */ 540 aitv = p->p_realtimer; 541 if (timerisset(&aitv.it_value)) 542 if (timercmp(&aitv.it_value, &time, <)) 543 timerclear(&aitv.it_value); 544 else 545 timevalsub(&aitv.it_value, &time); 546 } else 547 aitv = p->p_stats->p_timer[uap->which]; 548 splx(s); 549 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv, 550 sizeof (struct itimerval))); 551 } 552 553 #ifndef _SYS_SYSPROTO_H_ 554 struct setitimer_args { 555 u_int which; 556 struct itimerval *itv, *oitv; 557 }; 558 #endif 559 /* ARGSUSED */ 560 int 561 setitimer(p, uap, retval) 562 struct proc *p; 563 register struct setitimer_args *uap; 564 int *retval; 565 { 566 struct itimerval aitv; 567 register struct itimerval *itvp; 568 int s, error; 569 570 if (uap->which > ITIMER_PROF) 571 return (EINVAL); 572 itvp = uap->itv; 573 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 574 sizeof(struct itimerval)))) 575 return (error); 576 if ((uap->itv = uap->oitv) && 577 (error = getitimer(p, (struct getitimer_args *)uap, retval))) 578 return (error); 579 if (itvp == 0) 580 return (0); 581 if (itimerfix(&aitv.it_value)) 582 return (EINVAL); 583 if (!timerisset(&aitv.it_value)) 584 timerclear(&aitv.it_interval); 585 else if (itimerfix(&aitv.it_interval)) 586 return (EINVAL); 587 s = splclock(); 588 if (uap->which == ITIMER_REAL) { 589 if (timerisset(&p->p_realtimer.it_value)) 590 untimeout(realitexpire, (caddr_t)p, p->p_ithandle); 591 if (timerisset(&aitv.it_value)) { 592 timevaladd(&aitv.it_value, &time); 593 p->p_ithandle = timeout(realitexpire, (caddr_t)p, 594 hzto(&aitv.it_value)); 595 } 596 p->p_realtimer = aitv; 597 } else 598 p->p_stats->p_timer[uap->which] = aitv; 599 splx(s); 600 return (0); 601 } 602 603 /* 604 * Real interval timer expired: 605 * send process whose timer expired an alarm signal. 606 * If time is not set up to reload, then just return. 607 * Else compute next time timer should go off which is > current time. 608 * This is where delay in processing this timeout causes multiple 609 * SIGALRM calls to be compressed into one. 610 * hzto() always adds 1 to allow for the time until the next clock 611 * interrupt being strictly less than 1 clock tick, but we don't want 612 * that here since we want to appear to be in sync with the clock 613 * interrupt even when we're delayed. 614 */ 615 void 616 realitexpire(arg) 617 void *arg; 618 { 619 register struct proc *p; 620 int s; 621 622 p = (struct proc *)arg; 623 psignal(p, SIGALRM); 624 if (!timerisset(&p->p_realtimer.it_interval)) { 625 timerclear(&p->p_realtimer.it_value); 626 return; 627 } 628 for (;;) { 629 s = splclock(); 630 timevaladd(&p->p_realtimer.it_value, 631 &p->p_realtimer.it_interval); 632 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 633 p->p_ithandle = 634 timeout(realitexpire, (caddr_t)p, 635 hzto(&p->p_realtimer.it_value) - 1); 636 splx(s); 637 return; 638 } 639 splx(s); 640 } 641 } 642 643 /* 644 * Check that a proposed value to load into the .it_value or 645 * .it_interval part of an interval timer is acceptable, and 646 * fix it to have at least minimal value (i.e. if it is less 647 * than the resolution of the clock, round it up.) 648 */ 649 int 650 itimerfix(tv) 651 struct timeval *tv; 652 { 653 654 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 655 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 656 return (EINVAL); 657 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 658 tv->tv_usec = tick; 659 return (0); 660 } 661 662 /* 663 * Decrement an interval timer by a specified number 664 * of microseconds, which must be less than a second, 665 * i.e. < 1000000. If the timer expires, then reload 666 * it. In this case, carry over (usec - old value) to 667 * reduce the value reloaded into the timer so that 668 * the timer does not drift. This routine assumes 669 * that it is called in a context where the timers 670 * on which it is operating cannot change in value. 671 */ 672 int 673 itimerdecr(itp, usec) 674 register struct itimerval *itp; 675 int usec; 676 { 677 678 if (itp->it_value.tv_usec < usec) { 679 if (itp->it_value.tv_sec == 0) { 680 /* expired, and already in next interval */ 681 usec -= itp->it_value.tv_usec; 682 goto expire; 683 } 684 itp->it_value.tv_usec += 1000000; 685 itp->it_value.tv_sec--; 686 } 687 itp->it_value.tv_usec -= usec; 688 usec = 0; 689 if (timerisset(&itp->it_value)) 690 return (1); 691 /* expired, exactly at end of interval */ 692 expire: 693 if (timerisset(&itp->it_interval)) { 694 itp->it_value = itp->it_interval; 695 itp->it_value.tv_usec -= usec; 696 if (itp->it_value.tv_usec < 0) { 697 itp->it_value.tv_usec += 1000000; 698 itp->it_value.tv_sec--; 699 } 700 } else 701 itp->it_value.tv_usec = 0; /* sec is already 0 */ 702 return (0); 703 } 704 705 /* 706 * Add and subtract routines for timevals. 707 * N.B.: subtract routine doesn't deal with 708 * results which are before the beginning, 709 * it just gets very confused in this case. 710 * Caveat emptor. 711 */ 712 void 713 timevaladd(t1, t2) 714 struct timeval *t1, *t2; 715 { 716 717 t1->tv_sec += t2->tv_sec; 718 t1->tv_usec += t2->tv_usec; 719 timevalfix(t1); 720 } 721 722 void 723 timevalsub(t1, t2) 724 struct timeval *t1, *t2; 725 { 726 727 t1->tv_sec -= t2->tv_sec; 728 t1->tv_usec -= t2->tv_usec; 729 timevalfix(t1); 730 } 731 732 static void 733 timevalfix(t1) 734 struct timeval *t1; 735 { 736 737 if (t1->tv_usec < 0) { 738 t1->tv_sec--; 739 t1->tv_usec += 1000000; 740 } 741 if (t1->tv_usec >= 1000000) { 742 t1->tv_sec++; 743 t1->tv_usec -= 1000000; 744 } 745 } 746