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/resourcevar.h> 39 #include <sys/kernel.h> 40 #include <sys/systm.h> 41 #include <sys/proc.h> 42 #include <sys/vnode.h> 43 44 #include <machine/cpu.h> 45 46 void timevaladd __P((struct timeval *, struct timeval *)); 47 void timevalsub __P((struct timeval *, struct timeval *)); 48 void timevalfix __P((struct timeval *)); 49 50 /* 51 * Time of day and interval timer support. 52 * 53 * These routines provide the kernel entry points to get and set 54 * the time-of-day and per-process interval timers. Subroutines 55 * here provide support for adding and subtracting timeval structures 56 * and decrementing interval timers, optionally reloading the interval 57 * timers when they expire. 58 */ 59 60 struct gettimeofday_args { 61 struct timeval *tp; 62 struct timezone *tzp; 63 }; 64 /* ARGSUSED */ 65 int 66 gettimeofday(p, uap, retval) 67 struct proc *p; 68 register struct gettimeofday_args *uap; 69 int *retval; 70 { 71 struct timeval atv; 72 int error = 0; 73 74 if (uap->tp) { 75 microtime(&atv); 76 if (error = copyout((caddr_t)&atv, (caddr_t)uap->tp, 77 sizeof (atv))) 78 return (error); 79 } 80 if (uap->tzp) 81 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, 82 sizeof (tz)); 83 return (error); 84 } 85 86 struct settimeofday_args { 87 struct timeval *tv; 88 struct timezone *tzp; 89 }; 90 /* ARGSUSED */ 91 int 92 settimeofday(p, uap, retval) 93 struct proc *p; 94 struct settimeofday_args *uap; 95 int *retval; 96 { 97 struct timeval atv, delta; 98 struct timezone atz; 99 int error, s; 100 101 if (error = suser(p->p_ucred, &p->p_acflag)) 102 return (error); 103 /* Verify all parameters before changing time. */ 104 if (uap->tv && 105 (error = copyin((caddr_t)uap->tv, (caddr_t)&atv, sizeof(atv)))) 106 return (error); 107 if (uap->tzp && 108 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz)))) 109 return (error); 110 if (uap->tv) { 111 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 112 s = splclock(); 113 /* nb. delta.tv_usec may be < 0, but this is OK here */ 114 delta.tv_sec = atv.tv_sec - time.tv_sec; 115 delta.tv_usec = atv.tv_usec - time.tv_usec; 116 time = atv; 117 (void) splsoftclock(); 118 timevaladd(&boottime, &delta); 119 timevalfix(&boottime); 120 timevaladd(&runtime, &delta); 121 timevalfix(&runtime); 122 LEASE_UPDATETIME(delta.tv_sec); 123 splx(s); 124 resettodr(); 125 } 126 if (uap->tzp) 127 tz = atz; 128 return (0); 129 } 130 131 extern int tickadj; /* "standard" clock skew, us./tick */ 132 int tickdelta; /* current clock skew, us. per tick */ 133 long timedelta; /* unapplied time correction, us. */ 134 long bigadj = 1000000; /* use 10x skew above bigadj us. */ 135 136 struct adjtime_args { 137 struct timeval *delta; 138 struct timeval *olddelta; 139 }; 140 /* ARGSUSED */ 141 int 142 adjtime(p, uap, retval) 143 struct proc *p; 144 register struct adjtime_args *uap; 145 int *retval; 146 { 147 struct timeval atv; 148 register long ndelta, ntickdelta, odelta; 149 int s, error; 150 151 if (error = suser(p->p_ucred, &p->p_acflag)) 152 return (error); 153 if (error = 154 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval))) 155 return (error); 156 157 /* 158 * Compute the total correction and the rate at which to apply it. 159 * Round the adjustment down to a whole multiple of the per-tick 160 * delta, so that after some number of incremental changes in 161 * hardclock(), tickdelta will become zero, lest the correction 162 * overshoot and start taking us away from the desired final time. 163 */ 164 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 165 if (ndelta > bigadj) 166 ntickdelta = 10 * tickadj; 167 else 168 ntickdelta = tickadj; 169 if (ndelta % ntickdelta) 170 ndelta = ndelta / ntickdelta * ntickdelta; 171 172 /* 173 * To make hardclock()'s job easier, make the per-tick delta negative 174 * if we want time to run slower; then hardclock can simply compute 175 * tick + tickdelta, and subtract tickdelta from timedelta. 176 */ 177 if (ndelta < 0) 178 ntickdelta = -ntickdelta; 179 s = splclock(); 180 odelta = timedelta; 181 timedelta = ndelta; 182 tickdelta = ntickdelta; 183 splx(s); 184 185 if (uap->olddelta) { 186 atv.tv_sec = odelta / 1000000; 187 atv.tv_usec = odelta % 1000000; 188 (void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta, 189 sizeof(struct timeval)); 190 } 191 return (0); 192 } 193 194 /* 195 * Get value of an interval timer. The process virtual and 196 * profiling virtual time timers are kept in the p_stats area, since 197 * they can be swapped out. These are kept internally in the 198 * way they are specified externally: in time until they expire. 199 * 200 * The real time interval timer is kept in the process table slot 201 * for the process, and its value (it_value) is kept as an 202 * absolute time rather than as a delta, so that it is easy to keep 203 * periodic real-time signals from drifting. 204 * 205 * Virtual time timers are processed in the hardclock() routine of 206 * kern_clock.c. The real time timer is processed by a timeout 207 * routine, called from the softclock() routine. Since a callout 208 * may be delayed in real time due to interrupt processing in the system, 209 * it is possible for the real time timeout routine (realitexpire, given below), 210 * to be delayed in real time past when it is supposed to occur. It 211 * does not suffice, therefore, to reload the real timer .it_value from the 212 * real time timers .it_interval. Rather, we compute the next time in 213 * absolute time the timer should go off. 214 */ 215 struct getitimer_args { 216 u_int which; 217 struct itimerval *itv; 218 }; 219 /* ARGSUSED */ 220 int 221 getitimer(p, uap, retval) 222 struct proc *p; 223 register struct getitimer_args *uap; 224 int *retval; 225 { 226 struct itimerval aitv; 227 int s; 228 229 if (uap->which > ITIMER_PROF) 230 return (EINVAL); 231 s = splclock(); 232 if (uap->which == ITIMER_REAL) { 233 /* 234 * Convert from absoulte to relative time in .it_value 235 * part of real time timer. If time for real time timer 236 * has passed return 0, else return difference between 237 * current time and time for the timer to go off. 238 */ 239 aitv = p->p_realtimer; 240 if (timerisset(&aitv.it_value)) 241 if (timercmp(&aitv.it_value, &time, <)) 242 timerclear(&aitv.it_value); 243 else 244 timevalsub(&aitv.it_value, 245 (struct timeval *)&time); 246 } else 247 aitv = p->p_stats->p_timer[uap->which]; 248 splx(s); 249 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv, 250 sizeof (struct itimerval))); 251 } 252 253 struct setitimer_args { 254 u_int which; 255 struct itimerval *itv, *oitv; 256 }; 257 /* ARGSUSED */ 258 int 259 setitimer(p, uap, retval) 260 struct proc *p; 261 register struct setitimer_args *uap; 262 int *retval; 263 { 264 struct itimerval aitv; 265 register struct itimerval *itvp; 266 int s, error; 267 268 if (uap->which > ITIMER_PROF) 269 return (EINVAL); 270 itvp = uap->itv; 271 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 272 sizeof(struct itimerval)))) 273 return (error); 274 if ((uap->itv = uap->oitv) && (error = getitimer(p, uap, retval))) 275 return (error); 276 if (itvp == 0) 277 return (0); 278 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) 279 return (EINVAL); 280 s = splclock(); 281 if (uap->which == ITIMER_REAL) { 282 untimeout(realitexpire, (caddr_t)p); 283 if (timerisset(&aitv.it_value)) { 284 timevaladd(&aitv.it_value, (struct timeval *)&time); 285 timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); 286 } 287 p->p_realtimer = aitv; 288 } else 289 p->p_stats->p_timer[uap->which] = aitv; 290 splx(s); 291 return (0); 292 } 293 294 /* 295 * Real interval timer expired: 296 * send process whose timer expired an alarm signal. 297 * If time is not set up to reload, then just return. 298 * Else compute next time timer should go off which is > current time. 299 * This is where delay in processing this timeout causes multiple 300 * SIGALRM calls to be compressed into one. 301 */ 302 void 303 realitexpire(arg) 304 void *arg; 305 { 306 register struct proc *p; 307 int s; 308 309 p = (struct proc *)arg; 310 psignal(p, SIGALRM); 311 if (!timerisset(&p->p_realtimer.it_interval)) { 312 timerclear(&p->p_realtimer.it_value); 313 return; 314 } 315 for (;;) { 316 s = splclock(); 317 timevaladd(&p->p_realtimer.it_value, 318 &p->p_realtimer.it_interval); 319 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 320 timeout(realitexpire, (caddr_t)p, 321 hzto(&p->p_realtimer.it_value)); 322 splx(s); 323 return; 324 } 325 splx(s); 326 } 327 } 328 329 /* 330 * Check that a proposed value to load into the .it_value or 331 * .it_interval part of an interval timer is acceptable, and 332 * fix it to have at least minimal value (i.e. if it is less 333 * than the resolution of the clock, round it up.) 334 */ 335 int 336 itimerfix(tv) 337 struct timeval *tv; 338 { 339 340 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 341 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 342 return (EINVAL); 343 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 344 tv->tv_usec = tick; 345 return (0); 346 } 347 348 /* 349 * Decrement an interval timer by a specified number 350 * of microseconds, which must be less than a second, 351 * i.e. < 1000000. If the timer expires, then reload 352 * it. In this case, carry over (usec - old value) to 353 * reduce the value reloaded into the timer so that 354 * the timer does not drift. This routine assumes 355 * that it is called in a context where the timers 356 * on which it is operating cannot change in value. 357 */ 358 int 359 itimerdecr(itp, usec) 360 register struct itimerval *itp; 361 int usec; 362 { 363 364 if (itp->it_value.tv_usec < usec) { 365 if (itp->it_value.tv_sec == 0) { 366 /* expired, and already in next interval */ 367 usec -= itp->it_value.tv_usec; 368 goto expire; 369 } 370 itp->it_value.tv_usec += 1000000; 371 itp->it_value.tv_sec--; 372 } 373 itp->it_value.tv_usec -= usec; 374 usec = 0; 375 if (timerisset(&itp->it_value)) 376 return (1); 377 /* expired, exactly at end of interval */ 378 expire: 379 if (timerisset(&itp->it_interval)) { 380 itp->it_value = itp->it_interval; 381 itp->it_value.tv_usec -= usec; 382 if (itp->it_value.tv_usec < 0) { 383 itp->it_value.tv_usec += 1000000; 384 itp->it_value.tv_sec--; 385 } 386 } else 387 itp->it_value.tv_usec = 0; /* sec is already 0 */ 388 return (0); 389 } 390 391 /* 392 * Add and subtract routines for timevals. 393 * N.B.: subtract routine doesn't deal with 394 * results which are before the beginning, 395 * it just gets very confused in this case. 396 * Caveat emptor. 397 */ 398 void 399 timevaladd(t1, t2) 400 struct timeval *t1, *t2; 401 { 402 403 t1->tv_sec += t2->tv_sec; 404 t1->tv_usec += t2->tv_usec; 405 timevalfix(t1); 406 } 407 408 void 409 timevalsub(t1, t2) 410 struct timeval *t1, *t2; 411 { 412 413 t1->tv_sec -= t2->tv_sec; 414 t1->tv_usec -= t2->tv_usec; 415 timevalfix(t1); 416 } 417 418 void 419 timevalfix(t1) 420 struct timeval *t1; 421 { 422 423 if (t1->tv_usec < 0) { 424 t1->tv_sec--; 425 t1->tv_usec += 1000000; 426 } 427 if (t1->tv_usec >= 1000000) { 428 t1->tv_sec++; 429 t1->tv_usec -= 1000000; 430 } 431 } 432