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 7.16 (Berkeley) 01/14/92 8 */ 9 10 #include "param.h" 11 #include "resourcevar.h" 12 #include "kernel.h" 13 #include "proc.h" 14 #include "vnode.h" 15 16 #include "machine/cpu.h" 17 18 /* 19 * Time of day and interval timer support. 20 * 21 * These routines provide the kernel entry points to get and set 22 * the time-of-day and per-process interval timers. Subroutines 23 * here provide support for adding and subtracting timeval structures 24 * and decrementing interval timers, optionally reloading the interval 25 * timers when they expire. 26 */ 27 28 /* ARGSUSED */ 29 gettimeofday(p, uap, retval) 30 struct proc *p; 31 register struct args { 32 struct timeval *tp; 33 struct timezone *tzp; 34 } *uap; 35 int *retval; 36 { 37 struct timeval atv; 38 int error = 0; 39 40 if (uap->tp) { 41 microtime(&atv); 42 if (error = copyout((caddr_t)&atv, (caddr_t)uap->tp, 43 sizeof (atv))) 44 return (error); 45 } 46 if (uap->tzp) 47 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, 48 sizeof (tz)); 49 return (error); 50 } 51 52 /* ARGSUSED */ 53 settimeofday(p, uap, retval) 54 struct proc *p; 55 struct args { 56 struct timeval *tv; 57 struct timezone *tzp; 58 } *uap; 59 int *retval; 60 { 61 struct timeval atv; 62 struct timezone atz; 63 int error, s; 64 65 if (error = suser(p->p_ucred, &p->p_acflag)) 66 return (error); 67 if (uap->tv) { 68 if (error = copyin((caddr_t)uap->tv, (caddr_t)&atv, 69 sizeof (struct timeval))) 70 return (error); 71 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 72 boottime.tv_sec += atv.tv_sec - time.tv_sec; 73 LEASE_UPDATETIME(atv.tv_sec - time.tv_sec); 74 s = splhigh(); time = atv; splx(s); 75 resettodr(); 76 } 77 if (uap->tzp && (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, 78 sizeof (atz))) == 0) 79 tz = atz; 80 return (error); 81 } 82 83 extern int tickadj; /* "standard" clock skew, us./tick */ 84 int tickdelta; /* current clock skew, us. per tick */ 85 long timedelta; /* unapplied time correction, us. */ 86 long bigadj = 1000000; /* use 10x skew above bigadj us. */ 87 88 /* ARGSUSED */ 89 adjtime(p, uap, retval) 90 struct proc *p; 91 register struct args { 92 struct timeval *delta; 93 struct timeval *olddelta; 94 } *uap; 95 int *retval; 96 { 97 struct timeval atv, oatv; 98 register long ndelta; 99 int s, error; 100 101 if (error = suser(p->p_ucred, &p->p_acflag)) 102 return (error); 103 if (error = 104 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof (struct timeval))) 105 return (error); 106 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 107 if (timedelta == 0) 108 if (ndelta > bigadj) 109 tickdelta = 10 * tickadj; 110 else 111 tickdelta = tickadj; 112 if (ndelta % tickdelta) 113 ndelta = ndelta / tickadj * tickadj; 114 115 s = splclock(); 116 if (uap->olddelta) { 117 oatv.tv_sec = timedelta / 1000000; 118 oatv.tv_usec = timedelta % 1000000; 119 } 120 timedelta = ndelta; 121 splx(s); 122 123 if (uap->olddelta) 124 (void) copyout((caddr_t)&oatv, (caddr_t)uap->olddelta, 125 sizeof (struct timeval)); 126 return (0); 127 } 128 129 /* 130 * Get value of an interval timer. The process virtual and 131 * profiling virtual time timers are kept in the p_stats area, since 132 * they can be swapped out. These are kept internally in the 133 * way they are specified externally: in time until they expire. 134 * 135 * The real time interval timer is kept in the process table slot 136 * for the process, and its value (it_value) is kept as an 137 * absolute time rather than as a delta, so that it is easy to keep 138 * periodic real-time signals from drifting. 139 * 140 * Virtual time timers are processed in the hardclock() routine of 141 * kern_clock.c. The real time timer is processed by a timeout 142 * routine, called from the softclock() routine. Since a callout 143 * may be delayed in real time due to interrupt processing in the system, 144 * it is possible for the real time timeout routine (realitexpire, given below), 145 * to be delayed in real time past when it is supposed to occur. It 146 * does not suffice, therefore, to reload the real timer .it_value from the 147 * real time timers .it_interval. Rather, we compute the next time in 148 * absolute time the timer should go off. 149 */ 150 /* ARGSUSED */ 151 getitimer(p, uap, retval) 152 struct proc *p; 153 register struct args { 154 u_int which; 155 struct itimerval *itv; 156 } *uap; 157 int *retval; 158 { 159 struct itimerval aitv; 160 int s; 161 162 if (uap->which > ITIMER_PROF) 163 return (EINVAL); 164 s = splclock(); 165 if (uap->which == ITIMER_REAL) { 166 /* 167 * Convert from absoulte to relative time in .it_value 168 * part of real time timer. If time for real time timer 169 * has passed return 0, else return difference between 170 * current time and time for the timer to go off. 171 */ 172 aitv = p->p_realtimer; 173 if (timerisset(&aitv.it_value)) 174 if (timercmp(&aitv.it_value, &time, <)) 175 timerclear(&aitv.it_value); 176 else 177 timevalsub(&aitv.it_value, &time); 178 } else 179 aitv = p->p_stats->p_timer[uap->which]; 180 splx(s); 181 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv, 182 sizeof (struct itimerval))); 183 } 184 185 /* ARGSUSED */ 186 setitimer(p, uap, retval) 187 struct proc *p; 188 register struct args { 189 u_int which; 190 struct itimerval *itv, *oitv; 191 } *uap; 192 int *retval; 193 { 194 struct itimerval aitv; 195 register struct itimerval *itvp; 196 int s, error; 197 198 if (uap->which > ITIMER_PROF) 199 return (EINVAL); 200 itvp = uap->itv; 201 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 202 sizeof(struct itimerval)))) 203 return (error); 204 if ((uap->itv = uap->oitv) && (error = getitimer(p, uap, retval))) 205 return (error); 206 if (itvp == 0) 207 return (0); 208 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) 209 return (EINVAL); 210 s = splclock(); 211 if (uap->which == ITIMER_REAL) { 212 untimeout(realitexpire, (caddr_t)p); 213 if (timerisset(&aitv.it_value)) { 214 timevaladd(&aitv.it_value, &time); 215 timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); 216 } 217 p->p_realtimer = aitv; 218 } else 219 p->p_stats->p_timer[uap->which] = aitv; 220 splx(s); 221 return (0); 222 } 223 224 /* 225 * Real interval timer expired: 226 * send process whose timer expired an alarm signal. 227 * If time is not set up to reload, then just return. 228 * Else compute next time timer should go off which is > current time. 229 * This is where delay in processing this timeout causes multiple 230 * SIGALRM calls to be compressed into one. 231 */ 232 realitexpire(p) 233 register struct proc *p; 234 { 235 int s; 236 237 psignal(p, SIGALRM); 238 if (!timerisset(&p->p_realtimer.it_interval)) { 239 timerclear(&p->p_realtimer.it_value); 240 return; 241 } 242 for (;;) { 243 s = splclock(); 244 timevaladd(&p->p_realtimer.it_value, 245 &p->p_realtimer.it_interval); 246 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 247 timeout(realitexpire, (caddr_t)p, 248 hzto(&p->p_realtimer.it_value)); 249 splx(s); 250 return; 251 } 252 splx(s); 253 } 254 } 255 256 /* 257 * Check that a proposed value to load into the .it_value or 258 * .it_interval part of an interval timer is acceptable, and 259 * fix it to have at least minimal value (i.e. if it is less 260 * than the resolution of the clock, round it up.) 261 */ 262 itimerfix(tv) 263 struct timeval *tv; 264 { 265 266 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 267 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 268 return (EINVAL); 269 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 270 tv->tv_usec = tick; 271 return (0); 272 } 273 274 /* 275 * Decrement an interval timer by a specified number 276 * of microseconds, which must be less than a second, 277 * i.e. < 1000000. If the timer expires, then reload 278 * it. In this case, carry over (usec - old value) to 279 * reducint the value reloaded into the timer so that 280 * the timer does not drift. This routine assumes 281 * that it is called in a context where the timers 282 * on which it is operating cannot change in value. 283 */ 284 itimerdecr(itp, usec) 285 register struct itimerval *itp; 286 int usec; 287 { 288 289 if (itp->it_value.tv_usec < usec) { 290 if (itp->it_value.tv_sec == 0) { 291 /* expired, and already in next interval */ 292 usec -= itp->it_value.tv_usec; 293 goto expire; 294 } 295 itp->it_value.tv_usec += 1000000; 296 itp->it_value.tv_sec--; 297 } 298 itp->it_value.tv_usec -= usec; 299 usec = 0; 300 if (timerisset(&itp->it_value)) 301 return (1); 302 /* expired, exactly at end of interval */ 303 expire: 304 if (timerisset(&itp->it_interval)) { 305 itp->it_value = itp->it_interval; 306 itp->it_value.tv_usec -= usec; 307 if (itp->it_value.tv_usec < 0) { 308 itp->it_value.tv_usec += 1000000; 309 itp->it_value.tv_sec--; 310 } 311 } else 312 itp->it_value.tv_usec = 0; /* sec is already 0 */ 313 return (0); 314 } 315 316 /* 317 * Add and subtract routines for timevals. 318 * N.B.: subtract routine doesn't deal with 319 * results which are before the beginning, 320 * it just gets very confused in this case. 321 * Caveat emptor. 322 */ 323 timevaladd(t1, t2) 324 struct timeval *t1, *t2; 325 { 326 327 t1->tv_sec += t2->tv_sec; 328 t1->tv_usec += t2->tv_usec; 329 timevalfix(t1); 330 } 331 332 timevalsub(t1, t2) 333 struct timeval *t1, *t2; 334 { 335 336 t1->tv_sec -= t2->tv_sec; 337 t1->tv_usec -= t2->tv_usec; 338 timevalfix(t1); 339 } 340 341 timevalfix(t1) 342 struct timeval *t1; 343 { 344 345 if (t1->tv_usec < 0) { 346 t1->tv_sec--; 347 t1->tv_usec += 1000000; 348 } 349 if (t1->tv_usec >= 1000000) { 350 t1->tv_sec++; 351 t1->tv_usec -= 1000000; 352 } 353 } 354