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 7.17 (Berkeley) 07/08/92 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 /* ARGSUSED */ 30 gettimeofday(p, uap, retval) 31 struct proc *p; 32 register struct args { 33 struct timeval *tp; 34 struct timezone *tzp; 35 } *uap; 36 int *retval; 37 { 38 struct timeval atv; 39 int error = 0; 40 41 if (uap->tp) { 42 microtime(&atv); 43 if (error = copyout((caddr_t)&atv, (caddr_t)uap->tp, 44 sizeof (atv))) 45 return (error); 46 } 47 if (uap->tzp) 48 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, 49 sizeof (tz)); 50 return (error); 51 } 52 53 /* ARGSUSED */ 54 settimeofday(p, uap, retval) 55 struct proc *p; 56 struct args { 57 struct timeval *tv; 58 struct timezone *tzp; 59 } *uap; 60 int *retval; 61 { 62 struct timeval atv, delta; 63 struct timezone atz; 64 int error, s; 65 66 if (error = suser(p->p_ucred, &p->p_acflag)) 67 return (error); 68 /* Verify all parameters before changing time. */ 69 if (uap->tv && 70 (error = copyin((caddr_t)uap->tv, (caddr_t)&atv, sizeof(atv)))) 71 return (error); 72 if (uap->tzp && 73 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz)))) 74 return (error); 75 if (uap->tv) { 76 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 77 s = splclock(); 78 /* nb. delta.tv_usec may be < 0, but this is OK here */ 79 delta.tv_sec = atv.tv_sec - time.tv_sec; 80 delta.tv_usec = atv.tv_usec - time.tv_usec; 81 time = atv; 82 (void) splsoftclock(); 83 timevaladd(&boottime, &delta); 84 timevalfix(&boottime); 85 timevaladd(&runtime, &delta); 86 timevalfix(&runtime); 87 LEASE_UPDATETIME(delta.tv_sec); 88 splx(s); 89 resettodr(); 90 } 91 if (uap->tzp) 92 tz = atz; 93 return (0); 94 } 95 96 extern int tickadj; /* "standard" clock skew, us./tick */ 97 int tickdelta; /* current clock skew, us. per tick */ 98 long timedelta; /* unapplied time correction, us. */ 99 long bigadj = 1000000; /* use 10x skew above bigadj us. */ 100 101 /* ARGSUSED */ 102 adjtime(p, uap, retval) 103 struct proc *p; 104 register struct args { 105 struct timeval *delta; 106 struct timeval *olddelta; 107 } *uap; 108 int *retval; 109 { 110 struct timeval atv, oatv; 111 register long ndelta; 112 int s, error; 113 114 if (error = suser(p->p_ucred, &p->p_acflag)) 115 return (error); 116 if (error = 117 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof (struct timeval))) 118 return (error); 119 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 120 if (timedelta == 0) 121 if (ndelta > bigadj) 122 tickdelta = 10 * tickadj; 123 else 124 tickdelta = tickadj; 125 if (ndelta % tickdelta) 126 ndelta = ndelta / tickadj * tickadj; 127 128 s = splclock(); 129 if (uap->olddelta) { 130 oatv.tv_sec = timedelta / 1000000; 131 oatv.tv_usec = timedelta % 1000000; 132 } 133 timedelta = ndelta; 134 splx(s); 135 136 if (uap->olddelta) 137 (void) copyout((caddr_t)&oatv, (caddr_t)uap->olddelta, 138 sizeof (struct timeval)); 139 return (0); 140 } 141 142 /* 143 * Get value of an interval timer. The process virtual and 144 * profiling virtual time timers are kept in the p_stats area, since 145 * they can be swapped out. These are kept internally in the 146 * way they are specified externally: in time until they expire. 147 * 148 * The real time interval timer is kept in the process table slot 149 * for the process, and its value (it_value) is kept as an 150 * absolute time rather than as a delta, so that it is easy to keep 151 * periodic real-time signals from drifting. 152 * 153 * Virtual time timers are processed in the hardclock() routine of 154 * kern_clock.c. The real time timer is processed by a timeout 155 * routine, called from the softclock() routine. Since a callout 156 * may be delayed in real time due to interrupt processing in the system, 157 * it is possible for the real time timeout routine (realitexpire, given below), 158 * to be delayed in real time past when it is supposed to occur. It 159 * does not suffice, therefore, to reload the real timer .it_value from the 160 * real time timers .it_interval. Rather, we compute the next time in 161 * absolute time the timer should go off. 162 */ 163 /* ARGSUSED */ 164 getitimer(p, uap, retval) 165 struct proc *p; 166 register struct args { 167 u_int which; 168 struct itimerval *itv; 169 } *uap; 170 int *retval; 171 { 172 struct itimerval aitv; 173 int s; 174 175 if (uap->which > ITIMER_PROF) 176 return (EINVAL); 177 s = splclock(); 178 if (uap->which == ITIMER_REAL) { 179 /* 180 * Convert from absoulte to relative time in .it_value 181 * part of real time timer. If time for real time timer 182 * has passed return 0, else return difference between 183 * current time and time for the timer to go off. 184 */ 185 aitv = p->p_realtimer; 186 if (timerisset(&aitv.it_value)) 187 if (timercmp(&aitv.it_value, &time, <)) 188 timerclear(&aitv.it_value); 189 else 190 timevalsub(&aitv.it_value, 191 (struct timeval *)&time); 192 } else 193 aitv = p->p_stats->p_timer[uap->which]; 194 splx(s); 195 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv, 196 sizeof (struct itimerval))); 197 } 198 199 /* ARGSUSED */ 200 setitimer(p, uap, retval) 201 struct proc *p; 202 register struct args { 203 u_int which; 204 struct itimerval *itv, *oitv; 205 } *uap; 206 int *retval; 207 { 208 struct itimerval aitv; 209 register struct itimerval *itvp; 210 int s, error; 211 212 if (uap->which > ITIMER_PROF) 213 return (EINVAL); 214 itvp = uap->itv; 215 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 216 sizeof(struct itimerval)))) 217 return (error); 218 if ((uap->itv = uap->oitv) && (error = getitimer(p, uap, retval))) 219 return (error); 220 if (itvp == 0) 221 return (0); 222 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) 223 return (EINVAL); 224 s = splclock(); 225 if (uap->which == ITIMER_REAL) { 226 untimeout(realitexpire, (caddr_t)p); 227 if (timerisset(&aitv.it_value)) { 228 timevaladd(&aitv.it_value, (struct timeval *)&time); 229 timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); 230 } 231 p->p_realtimer = aitv; 232 } else 233 p->p_stats->p_timer[uap->which] = aitv; 234 splx(s); 235 return (0); 236 } 237 238 /* 239 * Real interval timer expired: 240 * send process whose timer expired an alarm signal. 241 * If time is not set up to reload, then just return. 242 * Else compute next time timer should go off which is > current time. 243 * This is where delay in processing this timeout causes multiple 244 * SIGALRM calls to be compressed into one. 245 */ 246 void 247 realitexpire(arg) 248 void *arg; 249 { 250 register struct proc *p; 251 int s; 252 253 p = (struct proc *)arg; 254 psignal(p, SIGALRM); 255 if (!timerisset(&p->p_realtimer.it_interval)) { 256 timerclear(&p->p_realtimer.it_value); 257 return; 258 } 259 for (;;) { 260 s = splclock(); 261 timevaladd(&p->p_realtimer.it_value, 262 &p->p_realtimer.it_interval); 263 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 264 timeout(realitexpire, (caddr_t)p, 265 hzto(&p->p_realtimer.it_value)); 266 splx(s); 267 return; 268 } 269 splx(s); 270 } 271 } 272 273 /* 274 * Check that a proposed value to load into the .it_value or 275 * .it_interval part of an interval timer is acceptable, and 276 * fix it to have at least minimal value (i.e. if it is less 277 * than the resolution of the clock, round it up.) 278 */ 279 itimerfix(tv) 280 struct timeval *tv; 281 { 282 283 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 284 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 285 return (EINVAL); 286 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 287 tv->tv_usec = tick; 288 return (0); 289 } 290 291 /* 292 * Decrement an interval timer by a specified number 293 * of microseconds, which must be less than a second, 294 * i.e. < 1000000. If the timer expires, then reload 295 * it. In this case, carry over (usec - old value) to 296 * reduce the value reloaded into the timer so that 297 * the timer does not drift. This routine assumes 298 * that it is called in a context where the timers 299 * on which it is operating cannot change in value. 300 */ 301 itimerdecr(itp, usec) 302 register struct itimerval *itp; 303 int usec; 304 { 305 306 if (itp->it_value.tv_usec < usec) { 307 if (itp->it_value.tv_sec == 0) { 308 /* expired, and already in next interval */ 309 usec -= itp->it_value.tv_usec; 310 goto expire; 311 } 312 itp->it_value.tv_usec += 1000000; 313 itp->it_value.tv_sec--; 314 } 315 itp->it_value.tv_usec -= usec; 316 usec = 0; 317 if (timerisset(&itp->it_value)) 318 return (1); 319 /* expired, exactly at end of interval */ 320 expire: 321 if (timerisset(&itp->it_interval)) { 322 itp->it_value = itp->it_interval; 323 itp->it_value.tv_usec -= usec; 324 if (itp->it_value.tv_usec < 0) { 325 itp->it_value.tv_usec += 1000000; 326 itp->it_value.tv_sec--; 327 } 328 } else 329 itp->it_value.tv_usec = 0; /* sec is already 0 */ 330 return (0); 331 } 332 333 /* 334 * Add and subtract routines for timevals. 335 * N.B.: subtract routine doesn't deal with 336 * results which are before the beginning, 337 * it just gets very confused in this case. 338 * Caveat emptor. 339 */ 340 timevaladd(t1, t2) 341 struct timeval *t1, *t2; 342 { 343 344 t1->tv_sec += t2->tv_sec; 345 t1->tv_usec += t2->tv_usec; 346 timevalfix(t1); 347 } 348 349 timevalsub(t1, t2) 350 struct timeval *t1, *t2; 351 { 352 353 t1->tv_sec -= t2->tv_sec; 354 t1->tv_usec -= t2->tv_usec; 355 timevalfix(t1); 356 } 357 358 timevalfix(t1) 359 struct timeval *t1; 360 { 361 362 if (t1->tv_usec < 0) { 363 t1->tv_sec--; 364 t1->tv_usec += 1000000; 365 } 366 if (t1->tv_usec >= 1000000) { 367 t1->tv_sec++; 368 t1->tv_usec -= 1000000; 369 } 370 } 371