1 /* $NetBSD: kern_time.c,v 1.55 2001/06/11 07:07:12 tron Exp $ */ 2 3 /*- 4 * Copyright (c) 2000 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 /* 40 * Copyright (c) 1982, 1986, 1989, 1993 41 * The Regents of the University of California. All rights reserved. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. All advertising materials mentioning features or use of this software 52 * must display the following acknowledgement: 53 * This product includes software developed by the University of 54 * California, Berkeley and its contributors. 55 * 4. Neither the name of the University nor the names of its contributors 56 * may be used to endorse or promote products derived from this software 57 * without specific prior written permission. 58 * 59 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 60 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 61 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 62 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 63 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 64 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 65 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 66 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 67 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 68 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 69 * SUCH DAMAGE. 70 * 71 * @(#)kern_time.c 8.4 (Berkeley) 5/26/95 72 */ 73 74 #include "fs_nfs.h" 75 #include "opt_nfs.h" 76 #include "opt_nfsserver.h" 77 78 #include <sys/param.h> 79 #include <sys/resourcevar.h> 80 #include <sys/kernel.h> 81 #include <sys/systm.h> 82 #include <sys/proc.h> 83 #include <sys/vnode.h> 84 #include <sys/signalvar.h> 85 #include <sys/syslog.h> 86 87 #include <sys/mount.h> 88 #include <sys/syscallargs.h> 89 90 #include <uvm/uvm_extern.h> 91 92 #if defined(NFS) || defined(NFSSERVER) 93 #include <nfs/rpcv2.h> 94 #include <nfs/nfsproto.h> 95 #include <nfs/nfs_var.h> 96 #endif 97 98 #include <machine/cpu.h> 99 100 /* 101 * Time of day and interval timer support. 102 * 103 * These routines provide the kernel entry points to get and set 104 * the time-of-day and per-process interval timers. Subroutines 105 * here provide support for adding and subtracting timeval structures 106 * and decrementing interval timers, optionally reloading the interval 107 * timers when they expire. 108 */ 109 110 /* This function is used by clock_settime and settimeofday */ 111 int 112 settime(tv) 113 struct timeval *tv; 114 { 115 struct timeval delta; 116 struct cpu_info *ci; 117 int s; 118 119 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 120 s = splclock(); 121 timersub(tv, &time, &delta); 122 if ((delta.tv_sec < 0 || delta.tv_usec < 0) && securelevel > 1) { 123 splx(s); 124 return (EPERM); 125 } 126 #ifdef notyet 127 if ((delta.tv_sec < 86400) && securelevel > 0) { 128 splx(s); 129 return (EPERM); 130 } 131 #endif 132 time = *tv; 133 (void) spllowersoftclock(); 134 timeradd(&boottime, &delta, &boottime); 135 /* 136 * XXXSMP 137 * This is wrong. We should traverse a list of all 138 * CPUs and add the delta to the runtime of those 139 * CPUs which have a process on them. 140 */ 141 ci = curcpu(); 142 timeradd(&ci->ci_schedstate.spc_runtime, &delta, 143 &ci->ci_schedstate.spc_runtime); 144 # if (defined(NFS) && !defined (NFS_V2_ONLY)) || defined(NFSSERVER) 145 nqnfs_lease_updatetime(delta.tv_sec); 146 # endif 147 splx(s); 148 resettodr(); 149 return (0); 150 } 151 152 /* ARGSUSED */ 153 int 154 sys_clock_gettime(p, v, retval) 155 struct proc *p; 156 void *v; 157 register_t *retval; 158 { 159 struct sys_clock_gettime_args /* { 160 syscallarg(clockid_t) clock_id; 161 syscallarg(struct timespec *) tp; 162 } */ *uap = v; 163 clockid_t clock_id; 164 struct timeval atv; 165 struct timespec ats; 166 167 clock_id = SCARG(uap, clock_id); 168 if (clock_id != CLOCK_REALTIME) 169 return (EINVAL); 170 171 microtime(&atv); 172 TIMEVAL_TO_TIMESPEC(&atv,&ats); 173 174 return copyout(&ats, SCARG(uap, tp), sizeof(ats)); 175 } 176 177 /* ARGSUSED */ 178 int 179 sys_clock_settime(p, v, retval) 180 struct proc *p; 181 void *v; 182 register_t *retval; 183 { 184 struct sys_clock_settime_args /* { 185 syscallarg(clockid_t) clock_id; 186 syscallarg(const struct timespec *) tp; 187 } */ *uap = v; 188 clockid_t clock_id; 189 struct timeval atv; 190 struct timespec ats; 191 int error; 192 193 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 194 return (error); 195 196 clock_id = SCARG(uap, clock_id); 197 if (clock_id != CLOCK_REALTIME) 198 return (EINVAL); 199 200 if ((error = copyin(SCARG(uap, tp), &ats, sizeof(ats))) != 0) 201 return (error); 202 203 TIMESPEC_TO_TIMEVAL(&atv,&ats); 204 if ((error = settime(&atv))) 205 return (error); 206 207 return 0; 208 } 209 210 int 211 sys_clock_getres(p, v, retval) 212 struct proc *p; 213 void *v; 214 register_t *retval; 215 { 216 struct sys_clock_getres_args /* { 217 syscallarg(clockid_t) clock_id; 218 syscallarg(struct timespec *) tp; 219 } */ *uap = v; 220 clockid_t clock_id; 221 struct timespec ts; 222 int error = 0; 223 224 clock_id = SCARG(uap, clock_id); 225 if (clock_id != CLOCK_REALTIME) 226 return (EINVAL); 227 228 if (SCARG(uap, tp)) { 229 ts.tv_sec = 0; 230 ts.tv_nsec = 1000000000 / hz; 231 232 error = copyout(&ts, SCARG(uap, tp), sizeof(ts)); 233 } 234 235 return error; 236 } 237 238 /* ARGSUSED */ 239 int 240 sys_nanosleep(p, v, retval) 241 struct proc *p; 242 void *v; 243 register_t *retval; 244 { 245 static int nanowait; 246 struct sys_nanosleep_args/* { 247 syscallarg(struct timespec *) rqtp; 248 syscallarg(struct timespec *) rmtp; 249 } */ *uap = v; 250 struct timespec rqt; 251 struct timespec rmt; 252 struct timeval atv, utv; 253 int error, s, timo; 254 255 error = copyin((caddr_t)SCARG(uap, rqtp), (caddr_t)&rqt, 256 sizeof(struct timespec)); 257 if (error) 258 return (error); 259 260 TIMESPEC_TO_TIMEVAL(&atv,&rqt) 261 if (itimerfix(&atv)) 262 return (EINVAL); 263 264 s = splclock(); 265 timeradd(&atv,&time,&atv); 266 timo = hzto(&atv); 267 /* 268 * Avoid inadvertantly sleeping forever 269 */ 270 if (timo == 0) 271 timo = 1; 272 splx(s); 273 274 error = tsleep(&nanowait, PWAIT | PCATCH, "nanosleep", timo); 275 if (error == ERESTART) 276 error = EINTR; 277 if (error == EWOULDBLOCK) 278 error = 0; 279 280 if (SCARG(uap, rmtp)) { 281 int error; 282 283 s = splclock(); 284 utv = time; 285 splx(s); 286 287 timersub(&atv, &utv, &utv); 288 if (utv.tv_sec < 0) 289 timerclear(&utv); 290 291 TIMEVAL_TO_TIMESPEC(&utv,&rmt); 292 error = copyout((caddr_t)&rmt, (caddr_t)SCARG(uap,rmtp), 293 sizeof(rmt)); 294 if (error) 295 return (error); 296 } 297 298 return error; 299 } 300 301 /* ARGSUSED */ 302 int 303 sys_gettimeofday(p, v, retval) 304 struct proc *p; 305 void *v; 306 register_t *retval; 307 { 308 struct sys_gettimeofday_args /* { 309 syscallarg(struct timeval *) tp; 310 syscallarg(struct timezone *) tzp; 311 } */ *uap = v; 312 struct timeval atv; 313 int error = 0; 314 struct timezone tzfake; 315 316 if (SCARG(uap, tp)) { 317 microtime(&atv); 318 error = copyout(&atv, SCARG(uap, tp), sizeof(atv)); 319 if (error) 320 return (error); 321 } 322 if (SCARG(uap, tzp)) { 323 /* 324 * NetBSD has no kernel notion of time zone, so we just 325 * fake up a timezone struct and return it if demanded. 326 */ 327 tzfake.tz_minuteswest = 0; 328 tzfake.tz_dsttime = 0; 329 error = copyout(&tzfake, SCARG(uap, tzp), sizeof(tzfake)); 330 } 331 return (error); 332 } 333 334 /* ARGSUSED */ 335 int 336 sys_settimeofday(p, v, retval) 337 struct proc *p; 338 void *v; 339 register_t *retval; 340 { 341 struct sys_settimeofday_args /* { 342 syscallarg(const struct timeval *) tv; 343 syscallarg(const struct timezone *) tzp; 344 } */ *uap = v; 345 struct timeval atv; 346 struct timezone atz; 347 int error; 348 349 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 350 return (error); 351 /* Verify all parameters before changing time. */ 352 if (SCARG(uap, tv) && (error = copyin(SCARG(uap, tv), 353 &atv, sizeof(atv)))) 354 return (error); 355 /* XXX since we don't use tz, probably no point in doing copyin. */ 356 if (SCARG(uap, tzp) && (error = copyin(SCARG(uap, tzp), 357 &atz, sizeof(atz)))) 358 return (error); 359 if (SCARG(uap, tv)) 360 if ((error = settime(&atv))) 361 return (error); 362 /* 363 * NetBSD has no kernel notion of time zone, and only an 364 * obsolete program would try to set it, so we log a warning. 365 */ 366 if (SCARG(uap, tzp)) 367 log(LOG_WARNING, "pid %d attempted to set the " 368 "(obsolete) kernel time zone\n", p->p_pid); 369 return (0); 370 } 371 372 int tickdelta; /* current clock skew, us. per tick */ 373 long timedelta; /* unapplied time correction, us. */ 374 long bigadj = 1000000; /* use 10x skew above bigadj us. */ 375 376 /* ARGSUSED */ 377 int 378 sys_adjtime(p, v, retval) 379 struct proc *p; 380 void *v; 381 register_t *retval; 382 { 383 struct sys_adjtime_args /* { 384 syscallarg(const struct timeval *) delta; 385 syscallarg(struct timeval *) olddelta; 386 } */ *uap = v; 387 struct timeval atv; 388 long ndelta, ntickdelta, odelta; 389 int s, error; 390 391 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 392 return (error); 393 394 error = copyin(SCARG(uap, delta), &atv, sizeof(struct timeval)); 395 if (error) 396 return (error); 397 if (SCARG(uap, olddelta) != NULL && 398 uvm_useracc((caddr_t)SCARG(uap, olddelta), sizeof(struct timeval), 399 B_WRITE) == FALSE) 400 return (EFAULT); 401 402 /* 403 * Compute the total correction and the rate at which to apply it. 404 * Round the adjustment down to a whole multiple of the per-tick 405 * delta, so that after some number of incremental changes in 406 * hardclock(), tickdelta will become zero, lest the correction 407 * overshoot and start taking us away from the desired final time. 408 */ 409 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 410 if (ndelta > bigadj || ndelta < -bigadj) 411 ntickdelta = 10 * tickadj; 412 else 413 ntickdelta = tickadj; 414 if (ndelta % ntickdelta) 415 ndelta = ndelta / ntickdelta * ntickdelta; 416 417 /* 418 * To make hardclock()'s job easier, make the per-tick delta negative 419 * if we want time to run slower; then hardclock can simply compute 420 * tick + tickdelta, and subtract tickdelta from timedelta. 421 */ 422 if (ndelta < 0) 423 ntickdelta = -ntickdelta; 424 s = splclock(); 425 odelta = timedelta; 426 timedelta = ndelta; 427 tickdelta = ntickdelta; 428 splx(s); 429 430 if (SCARG(uap, olddelta)) { 431 atv.tv_sec = odelta / 1000000; 432 atv.tv_usec = odelta % 1000000; 433 (void) copyout(&atv, SCARG(uap, olddelta), 434 sizeof(struct timeval)); 435 } 436 return (0); 437 } 438 439 /* 440 * Get value of an interval timer. The process virtual and 441 * profiling virtual time timers are kept in the p_stats area, since 442 * they can be swapped out. These are kept internally in the 443 * way they are specified externally: in time until they expire. 444 * 445 * The real time interval timer is kept in the process table slot 446 * for the process, and its value (it_value) is kept as an 447 * absolute time rather than as a delta, so that it is easy to keep 448 * periodic real-time signals from drifting. 449 * 450 * Virtual time timers are processed in the hardclock() routine of 451 * kern_clock.c. The real time timer is processed by a timeout 452 * routine, called from the softclock() routine. Since a callout 453 * may be delayed in real time due to interrupt processing in the system, 454 * it is possible for the real time timeout routine (realitexpire, given below), 455 * to be delayed in real time past when it is supposed to occur. It 456 * does not suffice, therefore, to reload the real timer .it_value from the 457 * real time timers .it_interval. Rather, we compute the next time in 458 * absolute time the timer should go off. 459 */ 460 /* ARGSUSED */ 461 int 462 sys_getitimer(p, v, retval) 463 struct proc *p; 464 void *v; 465 register_t *retval; 466 { 467 struct sys_getitimer_args /* { 468 syscallarg(int) which; 469 syscallarg(struct itimerval *) itv; 470 } */ *uap = v; 471 int which = SCARG(uap, which); 472 struct itimerval aitv; 473 int s; 474 475 if ((u_int)which > ITIMER_PROF) 476 return (EINVAL); 477 s = splclock(); 478 if (which == ITIMER_REAL) { 479 /* 480 * Convert from absolute to relative time in .it_value 481 * part of real time timer. If time for real time timer 482 * has passed return 0, else return difference between 483 * current time and time for the timer to go off. 484 */ 485 aitv = p->p_realtimer; 486 if (timerisset(&aitv.it_value)) { 487 if (timercmp(&aitv.it_value, &time, <)) 488 timerclear(&aitv.it_value); 489 else 490 timersub(&aitv.it_value, &time, &aitv.it_value); 491 } 492 } else 493 aitv = p->p_stats->p_timer[which]; 494 splx(s); 495 return (copyout(&aitv, SCARG(uap, itv), sizeof(struct itimerval))); 496 } 497 498 /* ARGSUSED */ 499 int 500 sys_setitimer(p, v, retval) 501 struct proc *p; 502 void *v; 503 register_t *retval; 504 { 505 struct sys_setitimer_args /* { 506 syscallarg(int) which; 507 syscallarg(const struct itimerval *) itv; 508 syscallarg(struct itimerval *) oitv; 509 } */ *uap = v; 510 int which = SCARG(uap, which); 511 struct sys_getitimer_args getargs; 512 struct itimerval aitv; 513 const struct itimerval *itvp; 514 int s, error; 515 516 if ((u_int)which > ITIMER_PROF) 517 return (EINVAL); 518 itvp = SCARG(uap, itv); 519 if (itvp && (error = copyin(itvp, &aitv, sizeof(struct itimerval)))) 520 return (error); 521 if (SCARG(uap, oitv) != NULL) { 522 SCARG(&getargs, which) = which; 523 SCARG(&getargs, itv) = SCARG(uap, oitv); 524 if ((error = sys_getitimer(p, &getargs, retval)) != 0) 525 return (error); 526 } 527 if (itvp == 0) 528 return (0); 529 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) 530 return (EINVAL); 531 s = splclock(); 532 if (which == ITIMER_REAL) { 533 callout_stop(&p->p_realit_ch); 534 if (timerisset(&aitv.it_value)) { 535 /* 536 * Don't need to check hzto() return value, here. 537 * callout_reset() does it for us. 538 */ 539 timeradd(&aitv.it_value, &time, &aitv.it_value); 540 callout_reset(&p->p_realit_ch, hzto(&aitv.it_value), 541 realitexpire, p); 542 } 543 p->p_realtimer = aitv; 544 } else 545 p->p_stats->p_timer[which] = aitv; 546 splx(s); 547 return (0); 548 } 549 550 /* 551 * Real interval timer expired: 552 * send process whose timer expired an alarm signal. 553 * If time is not set up to reload, then just return. 554 * Else compute next time timer should go off which is > current time. 555 * This is where delay in processing this timeout causes multiple 556 * SIGALRM calls to be compressed into one. 557 */ 558 void 559 realitexpire(arg) 560 void *arg; 561 { 562 struct proc *p; 563 int s; 564 565 p = (struct proc *)arg; 566 psignal(p, SIGALRM); 567 if (!timerisset(&p->p_realtimer.it_interval)) { 568 timerclear(&p->p_realtimer.it_value); 569 return; 570 } 571 for (;;) { 572 s = splclock(); 573 timeradd(&p->p_realtimer.it_value, 574 &p->p_realtimer.it_interval, &p->p_realtimer.it_value); 575 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 576 /* 577 * Don't need to check hzto() return value, here. 578 * callout_reset() does it for us. 579 */ 580 callout_reset(&p->p_realit_ch, 581 hzto(&p->p_realtimer.it_value), realitexpire, p); 582 splx(s); 583 return; 584 } 585 splx(s); 586 } 587 } 588 589 /* 590 * Check that a proposed value to load into the .it_value or 591 * .it_interval part of an interval timer is acceptable, and 592 * fix it to have at least minimal value (i.e. if it is less 593 * than the resolution of the clock, round it up.) 594 */ 595 int 596 itimerfix(tv) 597 struct timeval *tv; 598 { 599 600 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 601 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 602 return (EINVAL); 603 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 604 tv->tv_usec = tick; 605 return (0); 606 } 607 608 /* 609 * Decrement an interval timer by a specified number 610 * of microseconds, which must be less than a second, 611 * i.e. < 1000000. If the timer expires, then reload 612 * it. In this case, carry over (usec - old value) to 613 * reduce the value reloaded into the timer so that 614 * the timer does not drift. This routine assumes 615 * that it is called in a context where the timers 616 * on which it is operating cannot change in value. 617 */ 618 int 619 itimerdecr(itp, usec) 620 struct itimerval *itp; 621 int usec; 622 { 623 624 if (itp->it_value.tv_usec < usec) { 625 if (itp->it_value.tv_sec == 0) { 626 /* expired, and already in next interval */ 627 usec -= itp->it_value.tv_usec; 628 goto expire; 629 } 630 itp->it_value.tv_usec += 1000000; 631 itp->it_value.tv_sec--; 632 } 633 itp->it_value.tv_usec -= usec; 634 usec = 0; 635 if (timerisset(&itp->it_value)) 636 return (1); 637 /* expired, exactly at end of interval */ 638 expire: 639 if (timerisset(&itp->it_interval)) { 640 itp->it_value = itp->it_interval; 641 itp->it_value.tv_usec -= usec; 642 if (itp->it_value.tv_usec < 0) { 643 itp->it_value.tv_usec += 1000000; 644 itp->it_value.tv_sec--; 645 } 646 } else 647 itp->it_value.tv_usec = 0; /* sec is already 0 */ 648 return (0); 649 } 650 651 /* 652 * ratecheck(): simple time-based rate-limit checking. see ratecheck(9) 653 * for usage and rationale. 654 */ 655 int 656 ratecheck(lasttime, mininterval) 657 struct timeval *lasttime; 658 const struct timeval *mininterval; 659 { 660 struct timeval tv, delta; 661 int s, rv = 0; 662 663 s = splclock(); 664 tv = mono_time; 665 splx(s); 666 667 timersub(&tv, lasttime, &delta); 668 669 /* 670 * check for 0,0 is so that the message will be seen at least once, 671 * even if interval is huge. 672 */ 673 if (timercmp(&delta, mininterval, >=) || 674 (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) { 675 *lasttime = tv; 676 rv = 1; 677 } 678 679 return (rv); 680 } 681 682 /* 683 * ppsratecheck(): packets (or events) per second limitation. 684 */ 685 int 686 ppsratecheck(lasttime, curpps, maxpps) 687 struct timeval *lasttime; 688 int *curpps; 689 int maxpps; /* maximum pps allowed */ 690 { 691 struct timeval tv, delta; 692 int s, rv; 693 694 s = splclock(); 695 tv = mono_time; 696 splx(s); 697 698 timersub(&tv, lasttime, &delta); 699 700 /* 701 * check for 0,0 is so that the message will be seen at least once. 702 * if more than one second have passed since the last update of 703 * lasttime, reset the counter. 704 * 705 * we do increment *curpps even in *curpps < maxpps case, as some may 706 * try to use *curpps for stat purposes as well. 707 */ 708 if ((lasttime->tv_sec == 0 && lasttime->tv_usec == 0) || 709 delta.tv_sec >= 1) { 710 *lasttime = tv; 711 *curpps = 0; 712 rv = 1; 713 } else if (maxpps < 0) 714 rv = 1; 715 else if (*curpps < maxpps) 716 rv = 1; 717 else 718 rv = 0; 719 720 #if 1 /*DIAGNOSTIC?*/ 721 /* be careful about wrap-around */ 722 if (*curpps + 1 > *curpps) 723 *curpps = *curpps + 1; 724 #else 725 /* 726 * assume that there's not too many calls to this function. 727 * not sure if the assumption holds, as it depends on *caller's* 728 * behavior, not the behavior of this function. 729 * IMHO it is wrong to make assumption on the caller's behavior, 730 * so the above #if is #if 1, not #ifdef DIAGNOSTIC. 731 */ 732 *curpps = *curpps + 1; 733 #endif 734 735 return (rv); 736 } 737