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 1.11 1995/11/12 06:43:02 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 #include <machine/cpu.h> 47 48 struct timezone tz; 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 #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 /* nb. delta.tv_usec may be < 0, but this is OK here */ 120 delta.tv_sec = atv.tv_sec - time.tv_sec; 121 delta.tv_usec = atv.tv_usec - time.tv_usec; 122 time = atv; /* XXX should avoid skew in tv_usec */ 123 (void) splsoftclock(); 124 timevalfix(&delta); 125 timevaladd(&boottime, &delta); 126 timevaladd(&runtime, &delta); 127 LEASE_UPDATETIME(delta.tv_sec); 128 splx(s); 129 resettodr(); 130 } 131 if (uap->tzp) 132 tz = atz; 133 return (0); 134 } 135 136 extern int tickadj; /* "standard" clock skew, us./tick */ 137 int tickdelta; /* current clock skew, us. per tick */ 138 long timedelta; /* unapplied time correction, us. */ 139 long bigadj = 1000000; /* use 10x skew above bigadj us. */ 140 141 #ifndef _SYS_SYSPROTO_H_ 142 struct adjtime_args { 143 struct timeval *delta; 144 struct timeval *olddelta; 145 }; 146 #endif 147 /* ARGSUSED */ 148 int 149 adjtime(p, uap, retval) 150 struct proc *p; 151 register struct adjtime_args *uap; 152 int *retval; 153 { 154 struct timeval atv; 155 register long ndelta, ntickdelta, odelta; 156 int s, error; 157 158 if ((error = suser(p->p_ucred, &p->p_acflag))) 159 return (error); 160 if ((error = 161 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval)))) 162 return (error); 163 164 /* 165 * Compute the total correction and the rate at which to apply it. 166 * Round the adjustment down to a whole multiple of the per-tick 167 * delta, so that after some number of incremental changes in 168 * hardclock(), tickdelta will become zero, lest the correction 169 * overshoot and start taking us away from the desired final time. 170 */ 171 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 172 if (ndelta > bigadj) 173 ntickdelta = 10 * tickadj; 174 else 175 ntickdelta = tickadj; 176 if (ndelta % ntickdelta) 177 ndelta = ndelta / ntickdelta * ntickdelta; 178 179 /* 180 * To make hardclock()'s job easier, make the per-tick delta negative 181 * if we want time to run slower; then hardclock can simply compute 182 * tick + tickdelta, and subtract tickdelta from timedelta. 183 */ 184 if (ndelta < 0) 185 ntickdelta = -ntickdelta; 186 s = splclock(); 187 odelta = timedelta; 188 timedelta = ndelta; 189 tickdelta = ntickdelta; 190 splx(s); 191 192 if (uap->olddelta) { 193 atv.tv_sec = odelta / 1000000; 194 atv.tv_usec = odelta % 1000000; 195 (void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta, 196 sizeof(struct timeval)); 197 } 198 return (0); 199 } 200 201 /* 202 * Get value of an interval timer. The process virtual and 203 * profiling virtual time timers are kept in the p_stats area, since 204 * they can be swapped out. These are kept internally in the 205 * way they are specified externally: in time until they expire. 206 * 207 * The real time interval timer is kept in the process table slot 208 * for the process, and its value (it_value) is kept as an 209 * absolute time rather than as a delta, so that it is easy to keep 210 * periodic real-time signals from drifting. 211 * 212 * Virtual time timers are processed in the hardclock() routine of 213 * kern_clock.c. The real time timer is processed by a timeout 214 * routine, called from the softclock() routine. Since a callout 215 * may be delayed in real time due to interrupt processing in the system, 216 * it is possible for the real time timeout routine (realitexpire, given below), 217 * to be delayed in real time past when it is supposed to occur. It 218 * does not suffice, therefore, to reload the real timer .it_value from the 219 * real time timers .it_interval. Rather, we compute the next time in 220 * absolute time the timer should go off. 221 */ 222 #ifndef _SYS_SYSPROTO_H_ 223 struct getitimer_args { 224 u_int which; 225 struct itimerval *itv; 226 }; 227 #endif 228 /* ARGSUSED */ 229 int 230 getitimer(p, uap, retval) 231 struct proc *p; 232 register struct getitimer_args *uap; 233 int *retval; 234 { 235 struct itimerval aitv; 236 int s; 237 238 if (uap->which > ITIMER_PROF) 239 return (EINVAL); 240 s = splclock(); 241 if (uap->which == ITIMER_REAL) { 242 /* 243 * Convert from absoulte to relative time in .it_value 244 * part of real time timer. If time for real time timer 245 * has passed return 0, else return difference between 246 * current time and time for the timer to go off. 247 */ 248 aitv = p->p_realtimer; 249 if (timerisset(&aitv.it_value)) 250 if (timercmp(&aitv.it_value, &time, <)) 251 timerclear(&aitv.it_value); 252 else 253 timevalsub(&aitv.it_value, 254 (struct timeval *)&time); 255 } else 256 aitv = p->p_stats->p_timer[uap->which]; 257 splx(s); 258 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv, 259 sizeof (struct itimerval))); 260 } 261 262 #ifndef _SYS_SYSPROTO_H_ 263 struct setitimer_args { 264 u_int which; 265 struct itimerval *itv, *oitv; 266 }; 267 #endif 268 /* ARGSUSED */ 269 int 270 setitimer(p, uap, retval) 271 struct proc *p; 272 register struct setitimer_args *uap; 273 int *retval; 274 { 275 struct itimerval aitv; 276 register struct itimerval *itvp; 277 int s, error; 278 279 if (uap->which > ITIMER_PROF) 280 return (EINVAL); 281 itvp = uap->itv; 282 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 283 sizeof(struct itimerval)))) 284 return (error); 285 if ((uap->itv = uap->oitv) && 286 (error = getitimer(p, (struct getitimer_args *)uap, retval))) 287 return (error); 288 if (itvp == 0) 289 return (0); 290 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) 291 return (EINVAL); 292 s = splclock(); 293 if (uap->which == ITIMER_REAL) { 294 untimeout(realitexpire, (caddr_t)p); 295 if (timerisset(&aitv.it_value)) { 296 timevaladd(&aitv.it_value, (struct timeval *)&time); 297 timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); 298 } 299 p->p_realtimer = aitv; 300 } else 301 p->p_stats->p_timer[uap->which] = aitv; 302 splx(s); 303 return (0); 304 } 305 306 /* 307 * Real interval timer expired: 308 * send process whose timer expired an alarm signal. 309 * If time is not set up to reload, then just return. 310 * Else compute next time timer should go off which is > current time. 311 * This is where delay in processing this timeout causes multiple 312 * SIGALRM calls to be compressed into one. 313 * hzto() always adds 1 to allow for the time until the next clock 314 * interrupt being strictly less than 1 clock tick, but we don't want 315 * that here since we want to appear to be in sync with the clock 316 * interrupt even when we're delayed. 317 */ 318 void 319 realitexpire(arg) 320 void *arg; 321 { 322 register struct proc *p; 323 int s; 324 325 p = (struct proc *)arg; 326 psignal(p, SIGALRM); 327 if (!timerisset(&p->p_realtimer.it_interval)) { 328 timerclear(&p->p_realtimer.it_value); 329 return; 330 } 331 for (;;) { 332 s = splclock(); 333 timevaladd(&p->p_realtimer.it_value, 334 &p->p_realtimer.it_interval); 335 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 336 timeout(realitexpire, (caddr_t)p, 337 hzto(&p->p_realtimer.it_value) - 1); 338 splx(s); 339 return; 340 } 341 splx(s); 342 } 343 } 344 345 /* 346 * Check that a proposed value to load into the .it_value or 347 * .it_interval part of an interval timer is acceptable, and 348 * fix it to have at least minimal value (i.e. if it is less 349 * than the resolution of the clock, round it up.) 350 */ 351 int 352 itimerfix(tv) 353 struct timeval *tv; 354 { 355 356 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 357 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 358 return (EINVAL); 359 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 360 tv->tv_usec = tick; 361 return (0); 362 } 363 364 /* 365 * Decrement an interval timer by a specified number 366 * of microseconds, which must be less than a second, 367 * i.e. < 1000000. If the timer expires, then reload 368 * it. In this case, carry over (usec - old value) to 369 * reduce the value reloaded into the timer so that 370 * the timer does not drift. This routine assumes 371 * that it is called in a context where the timers 372 * on which it is operating cannot change in value. 373 */ 374 int 375 itimerdecr(itp, usec) 376 register struct itimerval *itp; 377 int usec; 378 { 379 380 if (itp->it_value.tv_usec < usec) { 381 if (itp->it_value.tv_sec == 0) { 382 /* expired, and already in next interval */ 383 usec -= itp->it_value.tv_usec; 384 goto expire; 385 } 386 itp->it_value.tv_usec += 1000000; 387 itp->it_value.tv_sec--; 388 } 389 itp->it_value.tv_usec -= usec; 390 usec = 0; 391 if (timerisset(&itp->it_value)) 392 return (1); 393 /* expired, exactly at end of interval */ 394 expire: 395 if (timerisset(&itp->it_interval)) { 396 itp->it_value = itp->it_interval; 397 itp->it_value.tv_usec -= usec; 398 if (itp->it_value.tv_usec < 0) { 399 itp->it_value.tv_usec += 1000000; 400 itp->it_value.tv_sec--; 401 } 402 } else 403 itp->it_value.tv_usec = 0; /* sec is already 0 */ 404 return (0); 405 } 406 407 /* 408 * Add and subtract routines for timevals. 409 * N.B.: subtract routine doesn't deal with 410 * results which are before the beginning, 411 * it just gets very confused in this case. 412 * Caveat emptor. 413 */ 414 void 415 timevaladd(t1, t2) 416 struct timeval *t1, *t2; 417 { 418 419 t1->tv_sec += t2->tv_sec; 420 t1->tv_usec += t2->tv_usec; 421 timevalfix(t1); 422 } 423 424 void 425 timevalsub(t1, t2) 426 struct timeval *t1, *t2; 427 { 428 429 t1->tv_sec -= t2->tv_sec; 430 t1->tv_usec -= t2->tv_usec; 431 timevalfix(t1); 432 } 433 434 void 435 timevalfix(t1) 436 struct timeval *t1; 437 { 438 439 if (t1->tv_usec < 0) { 440 t1->tv_sec--; 441 t1->tv_usec += 1000000; 442 } 443 if (t1->tv_usec >= 1000000) { 444 t1->tv_sec++; 445 t1->tv_usec -= 1000000; 446 } 447 } 448