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 * $Id$ 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 s = splclock(); 118 /* 119 * Calculate delta directly to minimize clock interrupt 120 * latency. Fix it after the ipl has been lowered. 121 */ 122 delta.tv_sec = atv.tv_sec - time.tv_sec; 123 delta.tv_usec = atv.tv_usec - time.tv_usec; 124 time = atv; 125 /* 126 * XXX should arrange for microtime() to agree with atv if 127 * it is called now. As it is, it may add up to about 128 * `tick' unwanted usec. 129 * Another problem is that clock interrupts may occur at 130 * other than multiples of `tick'. It's not worth fixing 131 * this here, since the problem is also caused by tick 132 * adjustments. 133 */ 134 (void) splsoftclock(); 135 timevalfix(&delta); 136 timevaladd(&boottime, &delta); 137 timevaladd(&runtime, &delta); 138 /* re-use 'p' */ 139 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) 140 if (timerisset(&p->p_realtimer.it_value)) 141 timevaladd(&p->p_realtimer.it_value, &delta); 142 # ifdef NFS 143 lease_updatetime(delta.tv_sec); 144 # endif 145 splx(s); 146 resettodr(); 147 } 148 if (uap->tzp) 149 tz = atz; 150 return (0); 151 } 152 153 extern int tickadj; /* "standard" clock skew, us./tick */ 154 int tickdelta; /* current clock skew, us. per tick */ 155 long timedelta; /* unapplied time correction, us. */ 156 static long bigadj = 1000000; /* use 10x skew above bigadj us. */ 157 158 #ifndef _SYS_SYSPROTO_H_ 159 struct adjtime_args { 160 struct timeval *delta; 161 struct timeval *olddelta; 162 }; 163 #endif 164 /* ARGSUSED */ 165 int 166 adjtime(p, uap, retval) 167 struct proc *p; 168 register struct adjtime_args *uap; 169 int *retval; 170 { 171 struct timeval atv; 172 register long ndelta, ntickdelta, odelta; 173 int s, error; 174 175 if ((error = suser(p->p_ucred, &p->p_acflag))) 176 return (error); 177 if ((error = 178 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval)))) 179 return (error); 180 181 /* 182 * Compute the total correction and the rate at which to apply it. 183 * Round the adjustment down to a whole multiple of the per-tick 184 * delta, so that after some number of incremental changes in 185 * hardclock(), tickdelta will become zero, lest the correction 186 * overshoot and start taking us away from the desired final time. 187 */ 188 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 189 if (ndelta > bigadj || ndelta < -bigadj) 190 ntickdelta = 10 * tickadj; 191 else 192 ntickdelta = tickadj; 193 if (ndelta % ntickdelta) 194 ndelta = ndelta / ntickdelta * ntickdelta; 195 196 /* 197 * To make hardclock()'s job easier, make the per-tick delta negative 198 * if we want time to run slower; then hardclock can simply compute 199 * tick + tickdelta, and subtract tickdelta from timedelta. 200 */ 201 if (ndelta < 0) 202 ntickdelta = -ntickdelta; 203 s = splclock(); 204 odelta = timedelta; 205 timedelta = ndelta; 206 tickdelta = ntickdelta; 207 splx(s); 208 209 if (uap->olddelta) { 210 atv.tv_sec = odelta / 1000000; 211 atv.tv_usec = odelta % 1000000; 212 (void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta, 213 sizeof(struct timeval)); 214 } 215 return (0); 216 } 217 218 /* 219 * Get value of an interval timer. The process virtual and 220 * profiling virtual time timers are kept in the p_stats area, since 221 * they can be swapped out. These are kept internally in the 222 * way they are specified externally: in time until they expire. 223 * 224 * The real time interval timer is kept in the process table slot 225 * for the process, and its value (it_value) is kept as an 226 * absolute time rather than as a delta, so that it is easy to keep 227 * periodic real-time signals from drifting. 228 * 229 * Virtual time timers are processed in the hardclock() routine of 230 * kern_clock.c. The real time timer is processed by a timeout 231 * routine, called from the softclock() routine. Since a callout 232 * may be delayed in real time due to interrupt processing in the system, 233 * it is possible for the real time timeout routine (realitexpire, given below), 234 * to be delayed in real time past when it is supposed to occur. It 235 * does not suffice, therefore, to reload the real timer .it_value from the 236 * real time timers .it_interval. Rather, we compute the next time in 237 * absolute time the timer should go off. 238 */ 239 #ifndef _SYS_SYSPROTO_H_ 240 struct getitimer_args { 241 u_int which; 242 struct itimerval *itv; 243 }; 244 #endif 245 /* ARGSUSED */ 246 int 247 getitimer(p, uap, retval) 248 struct proc *p; 249 register struct getitimer_args *uap; 250 int *retval; 251 { 252 struct itimerval aitv; 253 int s; 254 255 if (uap->which > ITIMER_PROF) 256 return (EINVAL); 257 s = splclock(); 258 if (uap->which == ITIMER_REAL) { 259 /* 260 * Convert from absoulte to relative time in .it_value 261 * part of real time timer. If time for real time timer 262 * has passed return 0, else return difference between 263 * current time and time for the timer to go off. 264 */ 265 aitv = p->p_realtimer; 266 if (timerisset(&aitv.it_value)) 267 if (timercmp(&aitv.it_value, &time, <)) 268 timerclear(&aitv.it_value); 269 else 270 timevalsub(&aitv.it_value, 271 (struct timeval *)&time); 272 } else 273 aitv = p->p_stats->p_timer[uap->which]; 274 splx(s); 275 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv, 276 sizeof (struct itimerval))); 277 } 278 279 #ifndef _SYS_SYSPROTO_H_ 280 struct setitimer_args { 281 u_int which; 282 struct itimerval *itv, *oitv; 283 }; 284 #endif 285 /* ARGSUSED */ 286 int 287 setitimer(p, uap, retval) 288 struct proc *p; 289 register struct setitimer_args *uap; 290 int *retval; 291 { 292 struct itimerval aitv; 293 register struct itimerval *itvp; 294 int s, error; 295 296 if (uap->which > ITIMER_PROF) 297 return (EINVAL); 298 itvp = uap->itv; 299 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 300 sizeof(struct itimerval)))) 301 return (error); 302 if ((uap->itv = uap->oitv) && 303 (error = getitimer(p, (struct getitimer_args *)uap, retval))) 304 return (error); 305 if (itvp == 0) 306 return (0); 307 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) 308 return (EINVAL); 309 s = splclock(); 310 if (uap->which == ITIMER_REAL) { 311 untimeout(realitexpire, (caddr_t)p); 312 if (timerisset(&aitv.it_value)) { 313 timevaladd(&aitv.it_value, (struct timeval *)&time); 314 timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); 315 } 316 p->p_realtimer = aitv; 317 } else 318 p->p_stats->p_timer[uap->which] = aitv; 319 splx(s); 320 return (0); 321 } 322 323 /* 324 * Real interval timer expired: 325 * send process whose timer expired an alarm signal. 326 * If time is not set up to reload, then just return. 327 * Else compute next time timer should go off which is > current time. 328 * This is where delay in processing this timeout causes multiple 329 * SIGALRM calls to be compressed into one. 330 * hzto() always adds 1 to allow for the time until the next clock 331 * interrupt being strictly less than 1 clock tick, but we don't want 332 * that here since we want to appear to be in sync with the clock 333 * interrupt even when we're delayed. 334 */ 335 void 336 realitexpire(arg) 337 void *arg; 338 { 339 register struct proc *p; 340 int s; 341 342 p = (struct proc *)arg; 343 psignal(p, SIGALRM); 344 if (!timerisset(&p->p_realtimer.it_interval)) { 345 timerclear(&p->p_realtimer.it_value); 346 return; 347 } 348 for (;;) { 349 s = splclock(); 350 timevaladd(&p->p_realtimer.it_value, 351 &p->p_realtimer.it_interval); 352 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 353 timeout(realitexpire, (caddr_t)p, 354 hzto(&p->p_realtimer.it_value) - 1); 355 splx(s); 356 return; 357 } 358 splx(s); 359 } 360 } 361 362 /* 363 * Check that a proposed value to load into the .it_value or 364 * .it_interval part of an interval timer is acceptable, and 365 * fix it to have at least minimal value (i.e. if it is less 366 * than the resolution of the clock, round it up.) 367 */ 368 int 369 itimerfix(tv) 370 struct timeval *tv; 371 { 372 373 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 374 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 375 return (EINVAL); 376 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 377 tv->tv_usec = tick; 378 return (0); 379 } 380 381 /* 382 * Decrement an interval timer by a specified number 383 * of microseconds, which must be less than a second, 384 * i.e. < 1000000. If the timer expires, then reload 385 * it. In this case, carry over (usec - old value) to 386 * reduce the value reloaded into the timer so that 387 * the timer does not drift. This routine assumes 388 * that it is called in a context where the timers 389 * on which it is operating cannot change in value. 390 */ 391 int 392 itimerdecr(itp, usec) 393 register struct itimerval *itp; 394 int usec; 395 { 396 397 if (itp->it_value.tv_usec < usec) { 398 if (itp->it_value.tv_sec == 0) { 399 /* expired, and already in next interval */ 400 usec -= itp->it_value.tv_usec; 401 goto expire; 402 } 403 itp->it_value.tv_usec += 1000000; 404 itp->it_value.tv_sec--; 405 } 406 itp->it_value.tv_usec -= usec; 407 usec = 0; 408 if (timerisset(&itp->it_value)) 409 return (1); 410 /* expired, exactly at end of interval */ 411 expire: 412 if (timerisset(&itp->it_interval)) { 413 itp->it_value = itp->it_interval; 414 itp->it_value.tv_usec -= usec; 415 if (itp->it_value.tv_usec < 0) { 416 itp->it_value.tv_usec += 1000000; 417 itp->it_value.tv_sec--; 418 } 419 } else 420 itp->it_value.tv_usec = 0; /* sec is already 0 */ 421 return (0); 422 } 423 424 /* 425 * Add and subtract routines for timevals. 426 * N.B.: subtract routine doesn't deal with 427 * results which are before the beginning, 428 * it just gets very confused in this case. 429 * Caveat emptor. 430 */ 431 void 432 timevaladd(t1, t2) 433 struct timeval *t1, *t2; 434 { 435 436 t1->tv_sec += t2->tv_sec; 437 t1->tv_usec += t2->tv_usec; 438 timevalfix(t1); 439 } 440 441 void 442 timevalsub(t1, t2) 443 struct timeval *t1, *t2; 444 { 445 446 t1->tv_sec -= t2->tv_sec; 447 t1->tv_usec -= t2->tv_usec; 448 timevalfix(t1); 449 } 450 451 static void 452 timevalfix(t1) 453 struct timeval *t1; 454 { 455 456 if (t1->tv_usec < 0) { 457 t1->tv_sec--; 458 t1->tv_usec += 1000000; 459 } 460 if (t1->tv_usec >= 1000000) { 461 t1->tv_sec++; 462 t1->tv_usec -= 1000000; 463 } 464 } 465