1 /* $NetBSD: kern_time.c,v 1.14 1995/03/21 13:33:41 mycroft 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 45 #include <sys/mount.h> 46 #include <sys/syscallargs.h> 47 48 #include <machine/cpu.h> 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 /* ARGSUSED */ 61 int 62 gettimeofday(p, uap, retval) 63 struct proc *p; 64 register struct gettimeofday_args /* { 65 syscallarg(struct timeval *) tp; 66 syscallarg(struct timezone *) tzp; 67 } */ *uap; 68 register_t *retval; 69 { 70 struct timeval atv; 71 int error = 0; 72 73 if (SCARG(uap, tp)) { 74 microtime(&atv); 75 if (error = copyout((caddr_t)&atv, (caddr_t)SCARG(uap, tp), 76 sizeof (atv))) 77 return (error); 78 } 79 if (SCARG(uap, tzp)) 80 error = copyout((caddr_t)&tz, (caddr_t)SCARG(uap, tzp), 81 sizeof (tz)); 82 return (error); 83 } 84 85 /* ARGSUSED */ 86 int 87 settimeofday(p, uap, retval) 88 struct proc *p; 89 struct settimeofday_args /* { 90 syscallarg(struct timeval *) tv; 91 syscallarg(struct timezone *) tzp; 92 } */ *uap; 93 register_t *retval; 94 { 95 struct timeval atv, delta; 96 struct timezone atz; 97 int error, s; 98 99 if (error = suser(p->p_ucred, &p->p_acflag)) 100 return (error); 101 /* Verify all parameters before changing time. */ 102 if (SCARG(uap, tv) && (error = copyin((caddr_t)SCARG(uap, tv), 103 (caddr_t)&atv, sizeof(atv)))) 104 return (error); 105 if (SCARG(uap, tzp) && (error = copyin((caddr_t)SCARG(uap, tzp), 106 (caddr_t)&atz, sizeof(atz)))) 107 return (error); 108 if (SCARG(uap, tv)) { 109 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 110 s = splclock(); 111 timersub(&atv, &time, &delta); 112 time = atv; 113 (void) splsoftclock(); 114 timeradd(&boottime, &delta, &boottime); 115 timeradd(&runtime, &delta, &runtime); 116 # if defined(NFSCLIENT) || defined(NFSSERVER) 117 lease_updatetime(delta.tv_sec); 118 # endif 119 splx(s); 120 resettodr(); 121 } 122 if (SCARG(uap, tzp)) 123 tz = atz; 124 return (0); 125 } 126 127 int tickdelta; /* current clock skew, us. per tick */ 128 long timedelta; /* unapplied time correction, us. */ 129 long bigadj = 1000000; /* use 10x skew above bigadj us. */ 130 131 /* ARGSUSED */ 132 int 133 adjtime(p, uap, retval) 134 struct proc *p; 135 register struct adjtime_args /* { 136 syscallarg(struct timeval *) delta; 137 syscallarg(struct timeval *) olddelta; 138 } */ *uap; 139 register_t *retval; 140 { 141 struct timeval atv; 142 register long ndelta, ntickdelta, odelta; 143 int s, error; 144 145 if (error = suser(p->p_ucred, &p->p_acflag)) 146 return (error); 147 if (error = copyin((caddr_t)SCARG(uap, delta), (caddr_t)&atv, 148 sizeof(struct timeval))) 149 return (error); 150 151 /* 152 * Compute the total correction and the rate at which to apply it. 153 * Round the adjustment down to a whole multiple of the per-tick 154 * delta, so that after some number of incremental changes in 155 * hardclock(), tickdelta will become zero, lest the correction 156 * overshoot and start taking us away from the desired final time. 157 */ 158 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 159 if (ndelta > bigadj) 160 ntickdelta = 10 * tickadj; 161 else 162 ntickdelta = tickadj; 163 if (ndelta % ntickdelta) 164 ndelta = ndelta / ntickdelta * ntickdelta; 165 166 /* 167 * To make hardclock()'s job easier, make the per-tick delta negative 168 * if we want time to run slower; then hardclock can simply compute 169 * tick + tickdelta, and subtract tickdelta from timedelta. 170 */ 171 if (ndelta < 0) 172 ntickdelta = -ntickdelta; 173 s = splclock(); 174 odelta = timedelta; 175 timedelta = ndelta; 176 tickdelta = ntickdelta; 177 splx(s); 178 179 if (SCARG(uap, olddelta)) { 180 atv.tv_sec = odelta / 1000000; 181 atv.tv_usec = odelta % 1000000; 182 (void) copyout((caddr_t)&atv, (caddr_t)SCARG(uap, olddelta), 183 sizeof(struct timeval)); 184 } 185 return (0); 186 } 187 188 /* 189 * Get value of an interval timer. The process virtual and 190 * profiling virtual time timers are kept in the p_stats area, since 191 * they can be swapped out. These are kept internally in the 192 * way they are specified externally: in time until they expire. 193 * 194 * The real time interval timer is kept in the process table slot 195 * for the process, and its value (it_value) is kept as an 196 * absolute time rather than as a delta, so that it is easy to keep 197 * periodic real-time signals from drifting. 198 * 199 * Virtual time timers are processed in the hardclock() routine of 200 * kern_clock.c. The real time timer is processed by a timeout 201 * routine, called from the softclock() routine. Since a callout 202 * may be delayed in real time due to interrupt processing in the system, 203 * it is possible for the real time timeout routine (realitexpire, given below), 204 * to be delayed in real time past when it is supposed to occur. It 205 * does not suffice, therefore, to reload the real timer .it_value from the 206 * real time timers .it_interval. Rather, we compute the next time in 207 * absolute time the timer should go off. 208 */ 209 /* ARGSUSED */ 210 int 211 getitimer(p, uap, retval) 212 struct proc *p; 213 register struct getitimer_args /* { 214 syscallarg(u_int) which; 215 syscallarg(struct itimerval *) itv; 216 } */ *uap; 217 register_t *retval; 218 { 219 struct itimerval aitv; 220 int s; 221 222 if (SCARG(uap, which) > ITIMER_PROF) 223 return (EINVAL); 224 s = splclock(); 225 if (SCARG(uap, which) == ITIMER_REAL) { 226 /* 227 * Convert from absolute to relative time in .it_value 228 * part of real time timer. If time for real time timer 229 * has passed return 0, else return difference between 230 * current time and time for the timer to go off. 231 */ 232 aitv = p->p_realtimer; 233 if (timerisset(&aitv.it_value)) 234 if (timercmp(&aitv.it_value, &time, <)) 235 timerclear(&aitv.it_value); 236 else 237 timersub(&aitv.it_value, &time, &aitv.it_value); 238 } else 239 aitv = p->p_stats->p_timer[SCARG(uap, which)]; 240 splx(s); 241 return (copyout((caddr_t)&aitv, (caddr_t)SCARG(uap, itv), 242 sizeof (struct itimerval))); 243 } 244 245 /* ARGSUSED */ 246 int 247 setitimer(p, uap, retval) 248 struct proc *p; 249 register struct setitimer_args /* { 250 syscallarg(u_int) which; 251 syscallarg(struct itimerval *) itv; 252 syscallarg(struct itimerval *) oitv; 253 } */ *uap; 254 register_t *retval; 255 { 256 struct itimerval aitv; 257 register struct itimerval *itvp; 258 int s, error; 259 260 if (SCARG(uap, which) > ITIMER_PROF) 261 return (EINVAL); 262 itvp = SCARG(uap, itv); 263 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 264 sizeof(struct itimerval)))) 265 return (error); 266 if ((SCARG(uap, itv) = SCARG(uap, oitv)) && 267 (error = getitimer(p, uap, retval))) 268 return (error); 269 if (itvp == 0) 270 return (0); 271 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) 272 return (EINVAL); 273 s = splclock(); 274 if (SCARG(uap, which) == ITIMER_REAL) { 275 untimeout(realitexpire, p); 276 if (timerisset(&aitv.it_value)) { 277 timeradd(&aitv.it_value, &time, &aitv.it_value); 278 timeout(realitexpire, p, hzto(&aitv.it_value)); 279 } 280 p->p_realtimer = aitv; 281 } else 282 p->p_stats->p_timer[SCARG(uap, which)] = aitv; 283 splx(s); 284 return (0); 285 } 286 287 /* 288 * Real interval timer expired: 289 * send process whose timer expired an alarm signal. 290 * If time is not set up to reload, then just return. 291 * Else compute next time timer should go off which is > current time. 292 * This is where delay in processing this timeout causes multiple 293 * SIGALRM calls to be compressed into one. 294 */ 295 void 296 realitexpire(arg) 297 void *arg; 298 { 299 register struct proc *p; 300 int s; 301 302 p = (struct proc *)arg; 303 psignal(p, SIGALRM); 304 if (!timerisset(&p->p_realtimer.it_interval)) { 305 timerclear(&p->p_realtimer.it_value); 306 return; 307 } 308 for (;;) { 309 s = splclock(); 310 timeradd(&p->p_realtimer.it_value, 311 &p->p_realtimer.it_interval, &p->p_realtimer.it_value); 312 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 313 timeout(realitexpire, p, 314 hzto(&p->p_realtimer.it_value)); 315 splx(s); 316 return; 317 } 318 splx(s); 319 } 320 } 321 322 /* 323 * Check that a proposed value to load into the .it_value or 324 * .it_interval part of an interval timer is acceptable, and 325 * fix it to have at least minimal value (i.e. if it is less 326 * than the resolution of the clock, round it up.) 327 */ 328 int 329 itimerfix(tv) 330 struct timeval *tv; 331 { 332 333 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 334 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 335 return (EINVAL); 336 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 337 tv->tv_usec = tick; 338 return (0); 339 } 340 341 /* 342 * Decrement an interval timer by a specified number 343 * of microseconds, which must be less than a second, 344 * i.e. < 1000000. If the timer expires, then reload 345 * it. In this case, carry over (usec - old value) to 346 * reduce the value reloaded into the timer so that 347 * the timer does not drift. This routine assumes 348 * that it is called in a context where the timers 349 * on which it is operating cannot change in value. 350 */ 351 int 352 itimerdecr(itp, usec) 353 register struct itimerval *itp; 354 int usec; 355 { 356 357 if (itp->it_value.tv_usec < usec) { 358 if (itp->it_value.tv_sec == 0) { 359 /* expired, and already in next interval */ 360 usec -= itp->it_value.tv_usec; 361 goto expire; 362 } 363 itp->it_value.tv_usec += 1000000; 364 itp->it_value.tv_sec--; 365 } 366 itp->it_value.tv_usec -= usec; 367 usec = 0; 368 if (timerisset(&itp->it_value)) 369 return (1); 370 /* expired, exactly at end of interval */ 371 expire: 372 if (timerisset(&itp->it_interval)) { 373 itp->it_value = itp->it_interval; 374 itp->it_value.tv_usec -= usec; 375 if (itp->it_value.tv_usec < 0) { 376 itp->it_value.tv_usec += 1000000; 377 itp->it_value.tv_sec--; 378 } 379 } else 380 itp->it_value.tv_usec = 0; /* sec is already 0 */ 381 return (0); 382 } 383