1 /* 2 * Copyright (c) 1982, 1986, 1989 Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)kern_time.c 7.18 (Berkeley) 07/10/92 8 */ 9 10 #include "param.h" 11 #include "resourcevar.h" 12 #include "kernel.h" 13 #include "systm.h" 14 #include "proc.h" 15 #include "vnode.h" 16 17 #include "machine/cpu.h" 18 19 /* 20 * Time of day and interval timer support. 21 * 22 * These routines provide the kernel entry points to get and set 23 * the time-of-day and per-process interval timers. Subroutines 24 * here provide support for adding and subtracting timeval structures 25 * and decrementing interval timers, optionally reloading the interval 26 * timers when they expire. 27 */ 28 29 struct gettimeofday_args { 30 struct timeval *tp; 31 struct timezone *tzp; 32 }; 33 /* ARGSUSED */ 34 gettimeofday(p, uap, retval) 35 struct proc *p; 36 register struct gettimeofday_args *uap; 37 int *retval; 38 { 39 struct timeval atv; 40 int error = 0; 41 42 if (uap->tp) { 43 microtime(&atv); 44 if (error = copyout((caddr_t)&atv, (caddr_t)uap->tp, 45 sizeof (atv))) 46 return (error); 47 } 48 if (uap->tzp) 49 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, 50 sizeof (tz)); 51 return (error); 52 } 53 54 struct settimeofday_args { 55 struct timeval *tv; 56 struct timezone *tzp; 57 }; 58 /* ARGSUSED */ 59 settimeofday(p, uap, retval) 60 struct proc *p; 61 struct settimeofday_args *uap; 62 int *retval; 63 { 64 struct timeval atv, delta; 65 struct timezone atz; 66 int error, s; 67 68 if (error = suser(p->p_ucred, &p->p_acflag)) 69 return (error); 70 /* Verify all parameters before changing time. */ 71 if (uap->tv && 72 (error = copyin((caddr_t)uap->tv, (caddr_t)&atv, sizeof(atv)))) 73 return (error); 74 if (uap->tzp && 75 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz)))) 76 return (error); 77 if (uap->tv) { 78 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 79 s = splclock(); 80 /* nb. delta.tv_usec may be < 0, but this is OK here */ 81 delta.tv_sec = atv.tv_sec - time.tv_sec; 82 delta.tv_usec = atv.tv_usec - time.tv_usec; 83 time = atv; 84 (void) splsoftclock(); 85 timevaladd(&boottime, &delta); 86 timevalfix(&boottime); 87 timevaladd(&runtime, &delta); 88 timevalfix(&runtime); 89 LEASE_UPDATETIME(delta.tv_sec); 90 splx(s); 91 resettodr(); 92 } 93 if (uap->tzp) 94 tz = atz; 95 return (0); 96 } 97 98 extern int tickadj; /* "standard" clock skew, us./tick */ 99 int tickdelta; /* current clock skew, us. per tick */ 100 long timedelta; /* unapplied time correction, us. */ 101 long bigadj = 1000000; /* use 10x skew above bigadj us. */ 102 103 struct adjtime_args { 104 struct timeval *delta; 105 struct timeval *olddelta; 106 }; 107 /* ARGSUSED */ 108 adjtime(p, uap, retval) 109 struct proc *p; 110 register struct adjtime_args *uap; 111 int *retval; 112 { 113 struct timeval atv, oatv; 114 register long ndelta; 115 int s, error; 116 117 if (error = suser(p->p_ucred, &p->p_acflag)) 118 return (error); 119 if (error = 120 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof (struct timeval))) 121 return (error); 122 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 123 if (timedelta == 0) 124 if (ndelta > bigadj) 125 tickdelta = 10 * tickadj; 126 else 127 tickdelta = tickadj; 128 if (ndelta % tickdelta) 129 ndelta = ndelta / tickadj * tickadj; 130 131 s = splclock(); 132 if (uap->olddelta) { 133 oatv.tv_sec = timedelta / 1000000; 134 oatv.tv_usec = timedelta % 1000000; 135 } 136 timedelta = ndelta; 137 splx(s); 138 139 if (uap->olddelta) 140 (void) copyout((caddr_t)&oatv, (caddr_t)uap->olddelta, 141 sizeof (struct timeval)); 142 return (0); 143 } 144 145 /* 146 * Get value of an interval timer. The process virtual and 147 * profiling virtual time timers are kept in the p_stats area, since 148 * they can be swapped out. These are kept internally in the 149 * way they are specified externally: in time until they expire. 150 * 151 * The real time interval timer is kept in the process table slot 152 * for the process, and its value (it_value) is kept as an 153 * absolute time rather than as a delta, so that it is easy to keep 154 * periodic real-time signals from drifting. 155 * 156 * Virtual time timers are processed in the hardclock() routine of 157 * kern_clock.c. The real time timer is processed by a timeout 158 * routine, called from the softclock() routine. Since a callout 159 * may be delayed in real time due to interrupt processing in the system, 160 * it is possible for the real time timeout routine (realitexpire, given below), 161 * to be delayed in real time past when it is supposed to occur. It 162 * does not suffice, therefore, to reload the real timer .it_value from the 163 * real time timers .it_interval. Rather, we compute the next time in 164 * absolute time the timer should go off. 165 */ 166 struct getitimer_args { 167 u_int which; 168 struct itimerval *itv; 169 }; 170 /* ARGSUSED */ 171 getitimer(p, uap, retval) 172 struct proc *p; 173 register struct getitimer_args *uap; 174 int *retval; 175 { 176 struct itimerval aitv; 177 int s; 178 179 if (uap->which > ITIMER_PROF) 180 return (EINVAL); 181 s = splclock(); 182 if (uap->which == ITIMER_REAL) { 183 /* 184 * Convert from absoulte to relative time in .it_value 185 * part of real time timer. If time for real time timer 186 * has passed return 0, else return difference between 187 * current time and time for the timer to go off. 188 */ 189 aitv = p->p_realtimer; 190 if (timerisset(&aitv.it_value)) 191 if (timercmp(&aitv.it_value, &time, <)) 192 timerclear(&aitv.it_value); 193 else 194 timevalsub(&aitv.it_value, 195 (struct timeval *)&time); 196 } else 197 aitv = p->p_stats->p_timer[uap->which]; 198 splx(s); 199 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv, 200 sizeof (struct itimerval))); 201 } 202 203 struct setitimer_args { 204 u_int which; 205 struct itimerval *itv, *oitv; 206 }; 207 /* ARGSUSED */ 208 setitimer(p, uap, retval) 209 struct proc *p; 210 register struct setitimer_args *uap; 211 int *retval; 212 { 213 struct itimerval aitv; 214 register struct itimerval *itvp; 215 int s, error; 216 217 if (uap->which > ITIMER_PROF) 218 return (EINVAL); 219 itvp = uap->itv; 220 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 221 sizeof(struct itimerval)))) 222 return (error); 223 if ((uap->itv = uap->oitv) && (error = getitimer(p, uap, retval))) 224 return (error); 225 if (itvp == 0) 226 return (0); 227 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) 228 return (EINVAL); 229 s = splclock(); 230 if (uap->which == ITIMER_REAL) { 231 untimeout(realitexpire, (caddr_t)p); 232 if (timerisset(&aitv.it_value)) { 233 timevaladd(&aitv.it_value, (struct timeval *)&time); 234 timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); 235 } 236 p->p_realtimer = aitv; 237 } else 238 p->p_stats->p_timer[uap->which] = aitv; 239 splx(s); 240 return (0); 241 } 242 243 /* 244 * Real interval timer expired: 245 * send process whose timer expired an alarm signal. 246 * If time is not set up to reload, then just return. 247 * Else compute next time timer should go off which is > current time. 248 * This is where delay in processing this timeout causes multiple 249 * SIGALRM calls to be compressed into one. 250 */ 251 void 252 realitexpire(arg) 253 void *arg; 254 { 255 register struct proc *p; 256 int s; 257 258 p = (struct proc *)arg; 259 psignal(p, SIGALRM); 260 if (!timerisset(&p->p_realtimer.it_interval)) { 261 timerclear(&p->p_realtimer.it_value); 262 return; 263 } 264 for (;;) { 265 s = splclock(); 266 timevaladd(&p->p_realtimer.it_value, 267 &p->p_realtimer.it_interval); 268 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 269 timeout(realitexpire, (caddr_t)p, 270 hzto(&p->p_realtimer.it_value)); 271 splx(s); 272 return; 273 } 274 splx(s); 275 } 276 } 277 278 /* 279 * Check that a proposed value to load into the .it_value or 280 * .it_interval part of an interval timer is acceptable, and 281 * fix it to have at least minimal value (i.e. if it is less 282 * than the resolution of the clock, round it up.) 283 */ 284 itimerfix(tv) 285 struct timeval *tv; 286 { 287 288 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 289 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 290 return (EINVAL); 291 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 292 tv->tv_usec = tick; 293 return (0); 294 } 295 296 /* 297 * Decrement an interval timer by a specified number 298 * of microseconds, which must be less than a second, 299 * i.e. < 1000000. If the timer expires, then reload 300 * it. In this case, carry over (usec - old value) to 301 * reduce the value reloaded into the timer so that 302 * the timer does not drift. This routine assumes 303 * that it is called in a context where the timers 304 * on which it is operating cannot change in value. 305 */ 306 itimerdecr(itp, usec) 307 register struct itimerval *itp; 308 int usec; 309 { 310 311 if (itp->it_value.tv_usec < usec) { 312 if (itp->it_value.tv_sec == 0) { 313 /* expired, and already in next interval */ 314 usec -= itp->it_value.tv_usec; 315 goto expire; 316 } 317 itp->it_value.tv_usec += 1000000; 318 itp->it_value.tv_sec--; 319 } 320 itp->it_value.tv_usec -= usec; 321 usec = 0; 322 if (timerisset(&itp->it_value)) 323 return (1); 324 /* expired, exactly at end of interval */ 325 expire: 326 if (timerisset(&itp->it_interval)) { 327 itp->it_value = itp->it_interval; 328 itp->it_value.tv_usec -= usec; 329 if (itp->it_value.tv_usec < 0) { 330 itp->it_value.tv_usec += 1000000; 331 itp->it_value.tv_sec--; 332 } 333 } else 334 itp->it_value.tv_usec = 0; /* sec is already 0 */ 335 return (0); 336 } 337 338 /* 339 * Add and subtract routines for timevals. 340 * N.B.: subtract routine doesn't deal with 341 * results which are before the beginning, 342 * it just gets very confused in this case. 343 * Caveat emptor. 344 */ 345 timevaladd(t1, t2) 346 struct timeval *t1, *t2; 347 { 348 349 t1->tv_sec += t2->tv_sec; 350 t1->tv_usec += t2->tv_usec; 351 timevalfix(t1); 352 } 353 354 timevalsub(t1, t2) 355 struct timeval *t1, *t2; 356 { 357 358 t1->tv_sec -= t2->tv_sec; 359 t1->tv_usec -= t2->tv_usec; 360 timevalfix(t1); 361 } 362 363 timevalfix(t1) 364 struct timeval *t1; 365 { 366 367 if (t1->tv_usec < 0) { 368 t1->tv_sec--; 369 t1->tv_usec += 1000000; 370 } 371 if (t1->tv_usec >= 1000000) { 372 t1->tv_sec++; 373 t1->tv_usec -= 1000000; 374 } 375 } 376