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 1.16 1996/06/08 11:55:32 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/proc.h> 44 #include <sys/vnode.h> 45 46 struct timezone tz; 47 48 /* 49 * Time of day and interval timer support. 50 * 51 * These routines provide the kernel entry points to get and set 52 * the time-of-day and per-process interval timers. Subroutines 53 * here provide support for adding and subtracting timeval structures 54 * and decrementing interval timers, optionally reloading the interval 55 * timers when they expire. 56 */ 57 58 static void timevalfix __P((struct timeval *)); 59 60 #ifndef _SYS_SYSPROTO_H_ 61 struct gettimeofday_args { 62 struct timeval *tp; 63 struct timezone *tzp; 64 }; 65 #endif 66 /* ARGSUSED */ 67 int 68 gettimeofday(p, uap, retval) 69 struct proc *p; 70 register struct gettimeofday_args *uap; 71 int *retval; 72 { 73 struct timeval atv; 74 int error = 0; 75 76 if (uap->tp) { 77 microtime(&atv); 78 if ((error = copyout((caddr_t)&atv, (caddr_t)uap->tp, 79 sizeof (atv)))) 80 return (error); 81 } 82 if (uap->tzp) 83 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, 84 sizeof (tz)); 85 return (error); 86 } 87 88 #ifndef _SYS_SYSPROTO_H_ 89 struct settimeofday_args { 90 struct timeval *tv; 91 struct timezone *tzp; 92 }; 93 #endif 94 /* ARGSUSED */ 95 int 96 settimeofday(p, uap, retval) 97 struct proc *p; 98 struct settimeofday_args *uap; 99 int *retval; 100 { 101 struct timeval atv, delta; 102 struct timezone atz; 103 int error, s; 104 105 if ((error = suser(p->p_ucred, &p->p_acflag))) 106 return (error); 107 /* Verify all parameters before changing time. */ 108 if (uap->tv && 109 (error = copyin((caddr_t)uap->tv, (caddr_t)&atv, sizeof(atv)))) 110 return (error); 111 if (atv.tv_usec < 0 || atv.tv_usec >= 1000000) 112 return (EINVAL); 113 if (uap->tzp && 114 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz)))) 115 return (error); 116 if (uap->tv) { 117 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 118 s = splclock(); 119 /* 120 * Calculate delta directly to minimize clock interrupt 121 * latency. Fix it after the ipl has been lowered. 122 */ 123 delta.tv_sec = atv.tv_sec - time.tv_sec; 124 delta.tv_usec = atv.tv_usec - time.tv_usec; 125 time = atv; 126 /* 127 * XXX should arrange for microtime() to agree with atv if 128 * it is called now. As it is, it may add up to about 129 * `tick' unwanted usec. 130 * Another problem is that clock interrupts may occur at 131 * other than multiples of `tick'. It's not worth fixing 132 * this here, since the problem is also caused by tick 133 * adjustments. 134 */ 135 (void) splsoftclock(); 136 timevalfix(&delta); 137 timevaladd(&boottime, &delta); 138 timevaladd(&runtime, &delta); 139 LEASE_UPDATETIME(delta.tv_sec); 140 splx(s); 141 resettodr(); 142 } 143 if (uap->tzp) 144 tz = atz; 145 return (0); 146 } 147 148 extern int tickadj; /* "standard" clock skew, us./tick */ 149 int tickdelta; /* current clock skew, us. per tick */ 150 long timedelta; /* unapplied time correction, us. */ 151 static long bigadj = 1000000; /* use 10x skew above bigadj us. */ 152 153 #ifndef _SYS_SYSPROTO_H_ 154 struct adjtime_args { 155 struct timeval *delta; 156 struct timeval *olddelta; 157 }; 158 #endif 159 /* ARGSUSED */ 160 int 161 adjtime(p, uap, retval) 162 struct proc *p; 163 register struct adjtime_args *uap; 164 int *retval; 165 { 166 struct timeval atv; 167 register long ndelta, ntickdelta, odelta; 168 int s, error; 169 170 if ((error = suser(p->p_ucred, &p->p_acflag))) 171 return (error); 172 if ((error = 173 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval)))) 174 return (error); 175 176 /* 177 * Compute the total correction and the rate at which to apply it. 178 * Round the adjustment down to a whole multiple of the per-tick 179 * delta, so that after some number of incremental changes in 180 * hardclock(), tickdelta will become zero, lest the correction 181 * overshoot and start taking us away from the desired final time. 182 */ 183 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 184 if (ndelta > bigadj || ndelta < -bigadj) 185 ntickdelta = 10 * tickadj; 186 else 187 ntickdelta = tickadj; 188 if (ndelta % ntickdelta) 189 ndelta = ndelta / ntickdelta * ntickdelta; 190 191 /* 192 * To make hardclock()'s job easier, make the per-tick delta negative 193 * if we want time to run slower; then hardclock can simply compute 194 * tick + tickdelta, and subtract tickdelta from timedelta. 195 */ 196 if (ndelta < 0) 197 ntickdelta = -ntickdelta; 198 s = splclock(); 199 odelta = timedelta; 200 timedelta = ndelta; 201 tickdelta = ntickdelta; 202 splx(s); 203 204 if (uap->olddelta) { 205 atv.tv_sec = odelta / 1000000; 206 atv.tv_usec = odelta % 1000000; 207 (void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta, 208 sizeof(struct timeval)); 209 } 210 return (0); 211 } 212 213 /* 214 * Get value of an interval timer. The process virtual and 215 * profiling virtual time timers are kept in the p_stats area, since 216 * they can be swapped out. These are kept internally in the 217 * way they are specified externally: in time until they expire. 218 * 219 * The real time interval timer is kept in the process table slot 220 * for the process, and its value (it_value) is kept as an 221 * absolute time rather than as a delta, so that it is easy to keep 222 * periodic real-time signals from drifting. 223 * 224 * Virtual time timers are processed in the hardclock() routine of 225 * kern_clock.c. The real time timer is processed by a timeout 226 * routine, called from the softclock() routine. Since a callout 227 * may be delayed in real time due to interrupt processing in the system, 228 * it is possible for the real time timeout routine (realitexpire, given below), 229 * to be delayed in real time past when it is supposed to occur. It 230 * does not suffice, therefore, to reload the real timer .it_value from the 231 * real time timers .it_interval. Rather, we compute the next time in 232 * absolute time the timer should go off. 233 */ 234 #ifndef _SYS_SYSPROTO_H_ 235 struct getitimer_args { 236 u_int which; 237 struct itimerval *itv; 238 }; 239 #endif 240 /* ARGSUSED */ 241 int 242 getitimer(p, uap, retval) 243 struct proc *p; 244 register struct getitimer_args *uap; 245 int *retval; 246 { 247 struct itimerval aitv; 248 int s; 249 250 if (uap->which > ITIMER_PROF) 251 return (EINVAL); 252 s = splclock(); 253 if (uap->which == ITIMER_REAL) { 254 /* 255 * Convert from absoulte to relative time in .it_value 256 * part of real time timer. If time for real time timer 257 * has passed return 0, else return difference between 258 * current time and time for the timer to go off. 259 */ 260 aitv = p->p_realtimer; 261 if (timerisset(&aitv.it_value)) 262 if (timercmp(&aitv.it_value, &time, <)) 263 timerclear(&aitv.it_value); 264 else 265 timevalsub(&aitv.it_value, 266 (struct timeval *)&time); 267 } else 268 aitv = p->p_stats->p_timer[uap->which]; 269 splx(s); 270 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv, 271 sizeof (struct itimerval))); 272 } 273 274 #ifndef _SYS_SYSPROTO_H_ 275 struct setitimer_args { 276 u_int which; 277 struct itimerval *itv, *oitv; 278 }; 279 #endif 280 /* ARGSUSED */ 281 int 282 setitimer(p, uap, retval) 283 struct proc *p; 284 register struct setitimer_args *uap; 285 int *retval; 286 { 287 struct itimerval aitv; 288 register struct itimerval *itvp; 289 int s, error; 290 291 if (uap->which > ITIMER_PROF) 292 return (EINVAL); 293 itvp = uap->itv; 294 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 295 sizeof(struct itimerval)))) 296 return (error); 297 if ((uap->itv = uap->oitv) && 298 (error = getitimer(p, (struct getitimer_args *)uap, retval))) 299 return (error); 300 if (itvp == 0) 301 return (0); 302 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) 303 return (EINVAL); 304 s = splclock(); 305 if (uap->which == ITIMER_REAL) { 306 untimeout(realitexpire, (caddr_t)p); 307 if (timerisset(&aitv.it_value)) { 308 timevaladd(&aitv.it_value, (struct timeval *)&time); 309 timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); 310 } 311 p->p_realtimer = aitv; 312 } else 313 p->p_stats->p_timer[uap->which] = aitv; 314 splx(s); 315 return (0); 316 } 317 318 /* 319 * Real interval timer expired: 320 * send process whose timer expired an alarm signal. 321 * If time is not set up to reload, then just return. 322 * Else compute next time timer should go off which is > current time. 323 * This is where delay in processing this timeout causes multiple 324 * SIGALRM calls to be compressed into one. 325 * hzto() always adds 1 to allow for the time until the next clock 326 * interrupt being strictly less than 1 clock tick, but we don't want 327 * that here since we want to appear to be in sync with the clock 328 * interrupt even when we're delayed. 329 */ 330 void 331 realitexpire(arg) 332 void *arg; 333 { 334 register struct proc *p; 335 int s; 336 337 p = (struct proc *)arg; 338 psignal(p, SIGALRM); 339 if (!timerisset(&p->p_realtimer.it_interval)) { 340 timerclear(&p->p_realtimer.it_value); 341 return; 342 } 343 for (;;) { 344 s = splclock(); 345 timevaladd(&p->p_realtimer.it_value, 346 &p->p_realtimer.it_interval); 347 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 348 timeout(realitexpire, (caddr_t)p, 349 hzto(&p->p_realtimer.it_value) - 1); 350 splx(s); 351 return; 352 } 353 splx(s); 354 } 355 } 356 357 /* 358 * Check that a proposed value to load into the .it_value or 359 * .it_interval part of an interval timer is acceptable, and 360 * fix it to have at least minimal value (i.e. if it is less 361 * than the resolution of the clock, round it up.) 362 */ 363 int 364 itimerfix(tv) 365 struct timeval *tv; 366 { 367 368 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 369 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 370 return (EINVAL); 371 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 372 tv->tv_usec = tick; 373 return (0); 374 } 375 376 /* 377 * Decrement an interval timer by a specified number 378 * of microseconds, which must be less than a second, 379 * i.e. < 1000000. If the timer expires, then reload 380 * it. In this case, carry over (usec - old value) to 381 * reduce the value reloaded into the timer so that 382 * the timer does not drift. This routine assumes 383 * that it is called in a context where the timers 384 * on which it is operating cannot change in value. 385 */ 386 int 387 itimerdecr(itp, usec) 388 register struct itimerval *itp; 389 int usec; 390 { 391 392 if (itp->it_value.tv_usec < usec) { 393 if (itp->it_value.tv_sec == 0) { 394 /* expired, and already in next interval */ 395 usec -= itp->it_value.tv_usec; 396 goto expire; 397 } 398 itp->it_value.tv_usec += 1000000; 399 itp->it_value.tv_sec--; 400 } 401 itp->it_value.tv_usec -= usec; 402 usec = 0; 403 if (timerisset(&itp->it_value)) 404 return (1); 405 /* expired, exactly at end of interval */ 406 expire: 407 if (timerisset(&itp->it_interval)) { 408 itp->it_value = itp->it_interval; 409 itp->it_value.tv_usec -= usec; 410 if (itp->it_value.tv_usec < 0) { 411 itp->it_value.tv_usec += 1000000; 412 itp->it_value.tv_sec--; 413 } 414 } else 415 itp->it_value.tv_usec = 0; /* sec is already 0 */ 416 return (0); 417 } 418 419 /* 420 * Add and subtract routines for timevals. 421 * N.B.: subtract routine doesn't deal with 422 * results which are before the beginning, 423 * it just gets very confused in this case. 424 * Caveat emptor. 425 */ 426 void 427 timevaladd(t1, t2) 428 struct timeval *t1, *t2; 429 { 430 431 t1->tv_sec += t2->tv_sec; 432 t1->tv_usec += t2->tv_usec; 433 timevalfix(t1); 434 } 435 436 void 437 timevalsub(t1, t2) 438 struct timeval *t1, *t2; 439 { 440 441 t1->tv_sec -= t2->tv_sec; 442 t1->tv_usec -= t2->tv_usec; 443 timevalfix(t1); 444 } 445 446 static void 447 timevalfix(t1) 448 struct timeval *t1; 449 { 450 451 if (t1->tv_usec < 0) { 452 t1->tv_sec--; 453 t1->tv_usec += 1000000; 454 } 455 if (t1->tv_usec >= 1000000) { 456 t1->tv_sec++; 457 t1->tv_usec -= 1000000; 458 } 459 } 460