kern_time.c revision 1.21
1/* $NetBSD: kern_time.c,v 1.21 1996/10/24 04:35:33 cgd Exp $ */ 2 3/* 4 * Copyright (c) 1982, 1986, 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)kern_time.c 8.1 (Berkeley) 6/10/93 36 */ 37 38#include <sys/param.h> 39#include <sys/resourcevar.h> 40#include <sys/kernel.h> 41#include <sys/systm.h> 42#include <sys/proc.h> 43#include <sys/vnode.h> 44#include <sys/signalvar.h> 45 46#include <sys/mount.h> 47#include <sys/syscallargs.h> 48 49#if defined(NFSCLIENT) || defined(NFSSERVER) 50#include <nfs/rpcv2.h> 51#include <nfs/nfsproto.h> 52#include <nfs/nfs_var.h> 53#endif 54 55#include <machine/cpu.h> 56 57/* 58 * Time of day and interval timer support. 59 * 60 * These routines provide the kernel entry points to get and set 61 * the time-of-day and per-process interval timers. Subroutines 62 * here provide support for adding and subtracting timeval structures 63 * and decrementing interval timers, optionally reloading the interval 64 * timers when they expire. 65 */ 66 67/* ARGSUSED */ 68int 69sys_gettimeofday(p, v, retval) 70 struct proc *p; 71 void *v; 72 register_t *retval; 73{ 74 register struct sys_gettimeofday_args /* { 75 syscallarg(struct timeval *) tp; 76 syscallarg(struct timezone *) tzp; 77 } */ *uap = v; 78 struct timeval atv; 79 int error = 0; 80 81 if (SCARG(uap, tp)) { 82 microtime(&atv); 83 error = copyout((caddr_t)&atv, (caddr_t)SCARG(uap, tp), 84 sizeof (atv)); 85 if (error) 86 return (error); 87 } 88 if (SCARG(uap, tzp)) 89 error = copyout((caddr_t)&tz, (caddr_t)SCARG(uap, tzp), 90 sizeof (tz)); 91 return (error); 92} 93 94/* ARGSUSED */ 95int 96sys_settimeofday(p, v, retval) 97 struct proc *p; 98 void *v; 99 register_t *retval; 100{ 101 struct sys_settimeofday_args /* { 102 syscallarg(struct timeval *) tv; 103 syscallarg(struct timezone *) tzp; 104 } */ *uap = v; 105 struct timeval atv, delta; 106 struct timezone atz; 107 int error, s; 108 109 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 110 return (error); 111 /* Verify all parameters before changing time. */ 112 if (SCARG(uap, tv) && (error = copyin((caddr_t)SCARG(uap, tv), 113 (caddr_t)&atv, sizeof(atv)))) 114 return (error); 115 if (SCARG(uap, tzp) && (error = copyin((caddr_t)SCARG(uap, tzp), 116 (caddr_t)&atz, sizeof(atz)))) 117 return (error); 118 if (SCARG(uap, tv)) { 119 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 120 s = splclock(); 121 timersub(&atv, &time, &delta); 122 time = atv; 123 (void) splsoftclock(); 124 timeradd(&boottime, &delta, &boottime); 125 timeradd(&runtime, &delta, &runtime); 126# if defined(NFSCLIENT) || defined(NFSSERVER) 127 nqnfs_lease_updatetime(delta.tv_sec); 128# endif 129 splx(s); 130 resettodr(); 131 } 132 if (SCARG(uap, tzp)) 133 tz = atz; 134 return (0); 135} 136 137int tickdelta; /* current clock skew, us. per tick */ 138long timedelta; /* unapplied time correction, us. */ 139long bigadj = 1000000; /* use 10x skew above bigadj us. */ 140 141/* ARGSUSED */ 142int 143sys_adjtime(p, v, retval) 144 struct proc *p; 145 void *v; 146 register_t *retval; 147{ 148 register struct sys_adjtime_args /* { 149 syscallarg(struct timeval *) delta; 150 syscallarg(struct timeval *) olddelta; 151 } */ *uap = v; 152 struct timeval atv; 153 register long ndelta, ntickdelta, odelta; 154 int s, error; 155 156 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 157 return (error); 158 159 error = copyin((caddr_t)SCARG(uap, delta), (caddr_t)&atv, 160 sizeof(struct timeval)); 161 if (error) 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 (SCARG(uap, olddelta)) { 193 atv.tv_sec = odelta / 1000000; 194 atv.tv_usec = odelta % 1000000; 195 (void) copyout((caddr_t)&atv, (caddr_t)SCARG(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/* ARGSUSED */ 223int 224sys_getitimer(p, v, retval) 225 struct proc *p; 226 void *v; 227 register_t *retval; 228{ 229 register struct sys_getitimer_args /* { 230 syscallarg(u_int) which; 231 syscallarg(struct itimerval *) itv; 232 } */ *uap = v; 233 struct itimerval aitv; 234 int s; 235 236 if (SCARG(uap, which) > ITIMER_PROF) 237 return (EINVAL); 238 s = splclock(); 239 if (SCARG(uap, which) == ITIMER_REAL) { 240 /* 241 * Convert from absolute to relative time in .it_value 242 * part of real time timer. If time for real time timer 243 * has passed return 0, else return difference between 244 * current time and time for the timer to go off. 245 */ 246 aitv = p->p_realtimer; 247 if (timerisset(&aitv.it_value)) 248 if (timercmp(&aitv.it_value, &time, <)) 249 timerclear(&aitv.it_value); 250 else 251 timersub(&aitv.it_value, &time, &aitv.it_value); 252 } else 253 aitv = p->p_stats->p_timer[SCARG(uap, which)]; 254 splx(s); 255 return (copyout((caddr_t)&aitv, (caddr_t)SCARG(uap, itv), 256 sizeof (struct itimerval))); 257} 258 259/* ARGSUSED */ 260int 261sys_setitimer(p, v, retval) 262 struct proc *p; 263 register void *v; 264 register_t *retval; 265{ 266 register struct sys_setitimer_args /* { 267 syscallarg(u_int) which; 268 syscallarg(struct itimerval *) itv; 269 syscallarg(struct itimerval *) oitv; 270 } */ *uap = v; 271 struct sys_getitimer_args getargs; 272 struct itimerval aitv; 273 register struct itimerval *itvp; 274 int s, error; 275 276 if (SCARG(uap, which) > ITIMER_PROF) 277 return (EINVAL); 278 itvp = SCARG(uap, itv); 279 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 280 sizeof(struct itimerval)))) 281 return (error); 282 if (SCARG(uap, oitv) != NULL) { 283 SCARG(&getargs, which) = SCARG(uap, which); 284 SCARG(&getargs, itv) = SCARG(uap, oitv); 285 if ((error = sys_getitimer(p, &getargs, retval)) != 0) 286 return (error); 287 } 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 (SCARG(uap, which) == ITIMER_REAL) { 294 untimeout(realitexpire, p); 295 if (timerisset(&aitv.it_value)) { 296 timeradd(&aitv.it_value, &time, &aitv.it_value); 297 timeout(realitexpire, p, hzto(&aitv.it_value)); 298 } 299 p->p_realtimer = aitv; 300 } else 301 p->p_stats->p_timer[SCARG(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 */ 314void 315realitexpire(arg) 316 void *arg; 317{ 318 register struct proc *p; 319 int s; 320 321 p = (struct proc *)arg; 322 psignal(p, SIGALRM); 323 if (!timerisset(&p->p_realtimer.it_interval)) { 324 timerclear(&p->p_realtimer.it_value); 325 return; 326 } 327 for (;;) { 328 s = splclock(); 329 timeradd(&p->p_realtimer.it_value, 330 &p->p_realtimer.it_interval, &p->p_realtimer.it_value); 331 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 332 timeout(realitexpire, p, 333 hzto(&p->p_realtimer.it_value)); 334 splx(s); 335 return; 336 } 337 splx(s); 338 } 339} 340 341/* 342 * Check that a proposed value to load into the .it_value or 343 * .it_interval part of an interval timer is acceptable, and 344 * fix it to have at least minimal value (i.e. if it is less 345 * than the resolution of the clock, round it up.) 346 */ 347int 348itimerfix(tv) 349 struct timeval *tv; 350{ 351 352 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 353 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 354 return (EINVAL); 355 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 356 tv->tv_usec = tick; 357 return (0); 358} 359 360/* 361 * Decrement an interval timer by a specified number 362 * of microseconds, which must be less than a second, 363 * i.e. < 1000000. If the timer expires, then reload 364 * it. In this case, carry over (usec - old value) to 365 * reduce the value reloaded into the timer so that 366 * the timer does not drift. This routine assumes 367 * that it is called in a context where the timers 368 * on which it is operating cannot change in value. 369 */ 370int 371itimerdecr(itp, usec) 372 register struct itimerval *itp; 373 int usec; 374{ 375 376 if (itp->it_value.tv_usec < usec) { 377 if (itp->it_value.tv_sec == 0) { 378 /* expired, and already in next interval */ 379 usec -= itp->it_value.tv_usec; 380 goto expire; 381 } 382 itp->it_value.tv_usec += 1000000; 383 itp->it_value.tv_sec--; 384 } 385 itp->it_value.tv_usec -= usec; 386 usec = 0; 387 if (timerisset(&itp->it_value)) 388 return (1); 389 /* expired, exactly at end of interval */ 390expire: 391 if (timerisset(&itp->it_interval)) { 392 itp->it_value = itp->it_interval; 393 itp->it_value.tv_usec -= usec; 394 if (itp->it_value.tv_usec < 0) { 395 itp->it_value.tv_usec += 1000000; 396 itp->it_value.tv_sec--; 397 } 398 } else 399 itp->it_value.tv_usec = 0; /* sec is already 0 */ 400 return (0); 401} 402