1 /* $NetBSD: kern_time.c,v 1.16 1995/10/07 06:28:28 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 sys_gettimeofday(p, v, retval) 63 struct proc *p; 64 void *v; 65 register_t *retval; 66 { 67 register struct sys_gettimeofday_args /* { 68 syscallarg(struct timeval *) tp; 69 syscallarg(struct timezone *) tzp; 70 } */ *uap = v; 71 struct timeval atv; 72 int error = 0; 73 74 if (SCARG(uap, tp)) { 75 microtime(&atv); 76 if (error = copyout((caddr_t)&atv, (caddr_t)SCARG(uap, tp), 77 sizeof (atv))) 78 return (error); 79 } 80 if (SCARG(uap, tzp)) 81 error = copyout((caddr_t)&tz, (caddr_t)SCARG(uap, tzp), 82 sizeof (tz)); 83 return (error); 84 } 85 86 /* ARGSUSED */ 87 int 88 sys_settimeofday(p, v, retval) 89 struct proc *p; 90 void *v; 91 register_t *retval; 92 { 93 struct sys_settimeofday_args /* { 94 syscallarg(struct timeval *) tv; 95 syscallarg(struct timezone *) tzp; 96 } */ *uap = v; 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 (SCARG(uap, tv) && (error = copyin((caddr_t)SCARG(uap, tv), 105 (caddr_t)&atv, sizeof(atv)))) 106 return (error); 107 if (SCARG(uap, tzp) && (error = copyin((caddr_t)SCARG(uap, tzp), 108 (caddr_t)&atz, sizeof(atz)))) 109 return (error); 110 if (SCARG(uap, tv)) { 111 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 112 s = splclock(); 113 timersub(&atv, &time, &delta); 114 time = atv; 115 (void) splsoftclock(); 116 timeradd(&boottime, &delta, &boottime); 117 timeradd(&runtime, &delta, &runtime); 118 # if defined(NFSCLIENT) || defined(NFSSERVER) 119 lease_updatetime(delta.tv_sec); 120 # endif 121 splx(s); 122 resettodr(); 123 } 124 if (SCARG(uap, tzp)) 125 tz = atz; 126 return (0); 127 } 128 129 int tickdelta; /* current clock skew, us. per tick */ 130 long timedelta; /* unapplied time correction, us. */ 131 long bigadj = 1000000; /* use 10x skew above bigadj us. */ 132 133 /* ARGSUSED */ 134 int 135 sys_adjtime(p, v, retval) 136 struct proc *p; 137 void *v; 138 register_t *retval; 139 { 140 register struct sys_adjtime_args /* { 141 syscallarg(struct timeval *) delta; 142 syscallarg(struct timeval *) olddelta; 143 } */ *uap = v; 144 struct timeval atv; 145 register long ndelta, ntickdelta, odelta; 146 int s, error; 147 148 if (error = suser(p->p_ucred, &p->p_acflag)) 149 return (error); 150 if (error = copyin((caddr_t)SCARG(uap, delta), (caddr_t)&atv, 151 sizeof(struct timeval))) 152 return (error); 153 154 /* 155 * Compute the total correction and the rate at which to apply it. 156 * Round the adjustment down to a whole multiple of the per-tick 157 * delta, so that after some number of incremental changes in 158 * hardclock(), tickdelta will become zero, lest the correction 159 * overshoot and start taking us away from the desired final time. 160 */ 161 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 162 if (ndelta > bigadj) 163 ntickdelta = 10 * tickadj; 164 else 165 ntickdelta = tickadj; 166 if (ndelta % ntickdelta) 167 ndelta = ndelta / ntickdelta * ntickdelta; 168 169 /* 170 * To make hardclock()'s job easier, make the per-tick delta negative 171 * if we want time to run slower; then hardclock can simply compute 172 * tick + tickdelta, and subtract tickdelta from timedelta. 173 */ 174 if (ndelta < 0) 175 ntickdelta = -ntickdelta; 176 s = splclock(); 177 odelta = timedelta; 178 timedelta = ndelta; 179 tickdelta = ntickdelta; 180 splx(s); 181 182 if (SCARG(uap, olddelta)) { 183 atv.tv_sec = odelta / 1000000; 184 atv.tv_usec = odelta % 1000000; 185 (void) copyout((caddr_t)&atv, (caddr_t)SCARG(uap, olddelta), 186 sizeof(struct timeval)); 187 } 188 return (0); 189 } 190 191 /* 192 * Get value of an interval timer. The process virtual and 193 * profiling virtual time timers are kept in the p_stats area, since 194 * they can be swapped out. These are kept internally in the 195 * way they are specified externally: in time until they expire. 196 * 197 * The real time interval timer is kept in the process table slot 198 * for the process, and its value (it_value) is kept as an 199 * absolute time rather than as a delta, so that it is easy to keep 200 * periodic real-time signals from drifting. 201 * 202 * Virtual time timers are processed in the hardclock() routine of 203 * kern_clock.c. The real time timer is processed by a timeout 204 * routine, called from the softclock() routine. Since a callout 205 * may be delayed in real time due to interrupt processing in the system, 206 * it is possible for the real time timeout routine (realitexpire, given below), 207 * to be delayed in real time past when it is supposed to occur. It 208 * does not suffice, therefore, to reload the real timer .it_value from the 209 * real time timers .it_interval. Rather, we compute the next time in 210 * absolute time the timer should go off. 211 */ 212 /* ARGSUSED */ 213 int 214 sys_getitimer(p, v, retval) 215 struct proc *p; 216 void *v; 217 register_t *retval; 218 { 219 register struct sys_getitimer_args /* { 220 syscallarg(u_int) which; 221 syscallarg(struct itimerval *) itv; 222 } */ *uap = v; 223 struct itimerval aitv; 224 int s; 225 226 if (SCARG(uap, which) > ITIMER_PROF) 227 return (EINVAL); 228 s = splclock(); 229 if (SCARG(uap, which) == ITIMER_REAL) { 230 /* 231 * Convert from absolute to relative time in .it_value 232 * part of real time timer. If time for real time timer 233 * has passed return 0, else return difference between 234 * current time and time for the timer to go off. 235 */ 236 aitv = p->p_realtimer; 237 if (timerisset(&aitv.it_value)) 238 if (timercmp(&aitv.it_value, &time, <)) 239 timerclear(&aitv.it_value); 240 else 241 timersub(&aitv.it_value, &time, &aitv.it_value); 242 } else 243 aitv = p->p_stats->p_timer[SCARG(uap, which)]; 244 splx(s); 245 return (copyout((caddr_t)&aitv, (caddr_t)SCARG(uap, itv), 246 sizeof (struct itimerval))); 247 } 248 249 /* ARGSUSED */ 250 int 251 sys_setitimer(p, v, retval) 252 struct proc *p; 253 void *v; 254 register_t *retval; 255 { 256 register struct sys_setitimer_args /* { 257 syscallarg(u_int) which; 258 syscallarg(struct itimerval *) itv; 259 syscallarg(struct itimerval *) oitv; 260 } */ *uap = v; 261 struct itimerval aitv; 262 register struct itimerval *itvp; 263 int s, error; 264 265 if (SCARG(uap, which) > ITIMER_PROF) 266 return (EINVAL); 267 itvp = SCARG(uap, itv); 268 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 269 sizeof(struct itimerval)))) 270 return (error); 271 if ((SCARG(uap, itv) = SCARG(uap, oitv)) && 272 (error = sys_getitimer(p, uap, retval))) 273 return (error); 274 if (itvp == 0) 275 return (0); 276 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) 277 return (EINVAL); 278 s = splclock(); 279 if (SCARG(uap, which) == ITIMER_REAL) { 280 untimeout(realitexpire, p); 281 if (timerisset(&aitv.it_value)) { 282 timeradd(&aitv.it_value, &time, &aitv.it_value); 283 timeout(realitexpire, p, hzto(&aitv.it_value)); 284 } 285 p->p_realtimer = aitv; 286 } else 287 p->p_stats->p_timer[SCARG(uap, which)] = aitv; 288 splx(s); 289 return (0); 290 } 291 292 /* 293 * Real interval timer expired: 294 * send process whose timer expired an alarm signal. 295 * If time is not set up to reload, then just return. 296 * Else compute next time timer should go off which is > current time. 297 * This is where delay in processing this timeout causes multiple 298 * SIGALRM calls to be compressed into one. 299 */ 300 void 301 realitexpire(arg) 302 void *arg; 303 { 304 register struct proc *p; 305 int s; 306 307 p = (struct proc *)arg; 308 psignal(p, SIGALRM); 309 if (!timerisset(&p->p_realtimer.it_interval)) { 310 timerclear(&p->p_realtimer.it_value); 311 return; 312 } 313 for (;;) { 314 s = splclock(); 315 timeradd(&p->p_realtimer.it_value, 316 &p->p_realtimer.it_interval, &p->p_realtimer.it_value); 317 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 318 timeout(realitexpire, p, 319 hzto(&p->p_realtimer.it_value)); 320 splx(s); 321 return; 322 } 323 splx(s); 324 } 325 } 326 327 /* 328 * Check that a proposed value to load into the .it_value or 329 * .it_interval part of an interval timer is acceptable, and 330 * fix it to have at least minimal value (i.e. if it is less 331 * than the resolution of the clock, round it up.) 332 */ 333 int 334 itimerfix(tv) 335 struct timeval *tv; 336 { 337 338 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 339 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 340 return (EINVAL); 341 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 342 tv->tv_usec = tick; 343 return (0); 344 } 345 346 /* 347 * Decrement an interval timer by a specified number 348 * of microseconds, which must be less than a second, 349 * i.e. < 1000000. If the timer expires, then reload 350 * it. In this case, carry over (usec - old value) to 351 * reduce the value reloaded into the timer so that 352 * the timer does not drift. This routine assumes 353 * that it is called in a context where the timers 354 * on which it is operating cannot change in value. 355 */ 356 int 357 itimerdecr(itp, usec) 358 register struct itimerval *itp; 359 int usec; 360 { 361 362 if (itp->it_value.tv_usec < usec) { 363 if (itp->it_value.tv_sec == 0) { 364 /* expired, and already in next interval */ 365 usec -= itp->it_value.tv_usec; 366 goto expire; 367 } 368 itp->it_value.tv_usec += 1000000; 369 itp->it_value.tv_sec--; 370 } 371 itp->it_value.tv_usec -= usec; 372 usec = 0; 373 if (timerisset(&itp->it_value)) 374 return (1); 375 /* expired, exactly at end of interval */ 376 expire: 377 if (timerisset(&itp->it_interval)) { 378 itp->it_value = itp->it_interval; 379 itp->it_value.tv_usec -= usec; 380 if (itp->it_value.tv_usec < 0) { 381 itp->it_value.tv_usec += 1000000; 382 itp->it_value.tv_sec--; 383 } 384 } else 385 itp->it_value.tv_usec = 0; /* sec is already 0 */ 386 return (0); 387 } 388