1 /* 2 * Copyright (c) 1982, 1986 Regents of the University of California. 3 * All rights reserved. The Berkeley software License Agreement 4 * specifies the terms and conditions for redistribution. 5 * 6 * @(#)kern_time.c 7.8 (Berkeley) 04/26/89 7 */ 8 9 #include "param.h" 10 #include "dir.h" /* XXX */ 11 #include "user.h" 12 #include "kernel.h" 13 #include "proc.h" 14 15 #include "machine/reg.h" 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 gettimeofday() 29 { 30 register struct a { 31 struct timeval *tp; 32 struct timezone *tzp; 33 } *uap = (struct a *)u.u_ap; 34 struct timeval atv; 35 36 if (uap->tp) { 37 microtime(&atv); 38 u.u_error = copyout((caddr_t)&atv, (caddr_t)uap->tp, 39 sizeof (atv)); 40 if (u.u_error) 41 return; 42 } 43 if (uap->tzp) 44 u.u_error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, 45 sizeof (tz)); 46 } 47 48 settimeofday() 49 { 50 register struct a { 51 struct timeval *tv; 52 struct timezone *tzp; 53 } *uap = (struct a *)u.u_ap; 54 struct timeval atv; 55 struct timezone atz; 56 57 if (uap->tv) { 58 u.u_error = copyin((caddr_t)uap->tv, (caddr_t)&atv, 59 sizeof (struct timeval)); 60 if (u.u_error) 61 return; 62 setthetime(&atv); 63 } 64 if (uap->tzp == 0 || (u.u_error = suser(u.u_cred, &u.u_acflag))) 65 return; 66 u.u_error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof (atz)); 67 if (u.u_error == 0) 68 tz = atz; 69 } 70 71 setthetime(tv) 72 struct timeval *tv; 73 { 74 int s; 75 76 if (u.u_error = suser(u.u_cred, &u.u_acflag)) 77 return; 78 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 79 boottime.tv_sec += tv->tv_sec - time.tv_sec; 80 s = splhigh(); time = *tv; splx(s); 81 resettodr(); 82 } 83 84 extern int tickadj; /* "standard" clock skew, us./tick */ 85 int tickdelta; /* current clock skew, us. per tick */ 86 long timedelta; /* unapplied time correction, us. */ 87 long bigadj = 1000000; /* use 10x skew above bigadj us. */ 88 89 adjtime() 90 { 91 register struct a { 92 struct timeval *delta; 93 struct timeval *olddelta; 94 } *uap = (struct a *)u.u_ap; 95 struct timeval atv, oatv; 96 register long ndelta; 97 int s; 98 99 if (u.u_error = suser(u.u_cred, &u.u_acflag)) 100 return; 101 u.u_error = copyin((caddr_t)uap->delta, (caddr_t)&atv, 102 sizeof (struct timeval)); 103 if (u.u_error) 104 return; 105 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 106 if (timedelta == 0) 107 if (ndelta > bigadj) 108 tickdelta = 10 * tickadj; 109 else 110 tickdelta = tickadj; 111 if (ndelta % tickdelta) 112 ndelta = ndelta / tickadj * tickadj; 113 114 s = splclock(); 115 if (uap->olddelta) { 116 oatv.tv_sec = timedelta / 1000000; 117 oatv.tv_usec = timedelta % 1000000; 118 } 119 timedelta = ndelta; 120 splx(s); 121 122 if (uap->olddelta) 123 (void) copyout((caddr_t)&oatv, (caddr_t)uap->olddelta, 124 sizeof (struct timeval)); 125 } 126 127 /* 128 * Get value of an interval timer. The process virtual and 129 * profiling virtual time timers are kept in the u. area, since 130 * they can be swapped out. These are kept internally in the 131 * way they are specified externally: in time until they expire. 132 * 133 * The real time interval timer is kept in the process table slot 134 * for the process, and its value (it_value) is kept as an 135 * absolute time rather than as a delta, so that it is easy to keep 136 * periodic real-time signals from drifting. 137 * 138 * Virtual time timers are processed in the hardclock() routine of 139 * kern_clock.c. The real time timer is processed by a timeout 140 * routine, called from the softclock() routine. Since a callout 141 * may be delayed in real time due to interrupt processing in the system, 142 * it is possible for the real time timeout routine (realitexpire, given below), 143 * to be delayed in real time past when it is supposed to occur. It 144 * does not suffice, therefore, to reload the real timer .it_value from the 145 * real time timers .it_interval. Rather, we compute the next time in 146 * absolute time the timer should go off. 147 */ 148 getitimer() 149 { 150 register struct a { 151 u_int which; 152 struct itimerval *itv; 153 } *uap = (struct a *)u.u_ap; 154 struct itimerval aitv; 155 int s; 156 157 if (uap->which > ITIMER_PROF) { 158 u.u_error = EINVAL; 159 return; 160 } 161 s = splclock(); 162 if (uap->which == ITIMER_REAL) { 163 /* 164 * Convert from absoulte to relative time in .it_value 165 * part of real time timer. If time for real time timer 166 * has passed return 0, else return difference between 167 * current time and time for the timer to go off. 168 */ 169 aitv = u.u_procp->p_realtimer; 170 if (timerisset(&aitv.it_value)) 171 if (timercmp(&aitv.it_value, &time, <)) 172 timerclear(&aitv.it_value); 173 else 174 timevalsub(&aitv.it_value, &time); 175 } else 176 aitv = u.u_timer[uap->which]; 177 splx(s); 178 u.u_error = copyout((caddr_t)&aitv, (caddr_t)uap->itv, 179 sizeof (struct itimerval)); 180 } 181 182 setitimer() 183 { 184 register struct a { 185 u_int which; 186 struct itimerval *itv, *oitv; 187 } *uap = (struct a *)u.u_ap; 188 struct itimerval aitv; 189 register struct itimerval *itvp; 190 int s; 191 register struct proc *p = u.u_procp; 192 193 if (uap->which > ITIMER_PROF) { 194 u.u_error = EINVAL; 195 return; 196 } 197 itvp = uap->itv; 198 if (itvp && (u.u_error = copyin((caddr_t)itvp, (caddr_t)&aitv, 199 sizeof(struct itimerval)))) 200 return; 201 if (uap->itv = uap->oitv) { 202 getitimer(); 203 if (u.u_error) 204 return; 205 } 206 if (itvp == 0) 207 return; 208 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) { 209 u.u_error = EINVAL; 210 return; 211 } 212 s = splclock(); 213 if (uap->which == ITIMER_REAL) { 214 untimeout(realitexpire, (caddr_t)p); 215 if (timerisset(&aitv.it_value)) { 216 timevaladd(&aitv.it_value, &time); 217 timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); 218 } 219 p->p_realtimer = aitv; 220 } else 221 u.u_timer[uap->which] = aitv; 222 splx(s); 223 } 224 225 /* 226 * Real interval timer expired: 227 * send process whose timer expired an alarm signal. 228 * If time is not set up to reload, then just return. 229 * Else compute next time timer should go off which is > current time. 230 * This is where delay in processing this timeout causes multiple 231 * SIGALRM calls to be compressed into one. 232 */ 233 realitexpire(p) 234 register struct proc *p; 235 { 236 int s; 237 238 psignal(p, SIGALRM); 239 if (!timerisset(&p->p_realtimer.it_interval)) { 240 timerclear(&p->p_realtimer.it_value); 241 return; 242 } 243 for (;;) { 244 s = splclock(); 245 timevaladd(&p->p_realtimer.it_value, 246 &p->p_realtimer.it_interval); 247 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 248 timeout(realitexpire, (caddr_t)p, 249 hzto(&p->p_realtimer.it_value)); 250 splx(s); 251 return; 252 } 253 splx(s); 254 } 255 } 256 257 /* 258 * Check that a proposed value to load into the .it_value or 259 * .it_interval part of an interval timer is acceptable, and 260 * fix it to have at least minimal value (i.e. if it is less 261 * than the resolution of the clock, round it up.) 262 */ 263 itimerfix(tv) 264 struct timeval *tv; 265 { 266 267 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 268 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 269 return (EINVAL); 270 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 271 tv->tv_usec = tick; 272 return (0); 273 } 274 275 /* 276 * Decrement an interval timer by a specified number 277 * of microseconds, which must be less than a second, 278 * i.e. < 1000000. If the timer expires, then reload 279 * it. In this case, carry over (usec - old value) to 280 * reducint the value reloaded into the timer so that 281 * the timer does not drift. This routine assumes 282 * that it is called in a context where the timers 283 * on which it is operating cannot change in value. 284 */ 285 itimerdecr(itp, usec) 286 register struct itimerval *itp; 287 int usec; 288 { 289 290 if (itp->it_value.tv_usec < usec) { 291 if (itp->it_value.tv_sec == 0) { 292 /* expired, and already in next interval */ 293 usec -= itp->it_value.tv_usec; 294 goto expire; 295 } 296 itp->it_value.tv_usec += 1000000; 297 itp->it_value.tv_sec--; 298 } 299 itp->it_value.tv_usec -= usec; 300 usec = 0; 301 if (timerisset(&itp->it_value)) 302 return (1); 303 /* expired, exactly at end of interval */ 304 expire: 305 if (timerisset(&itp->it_interval)) { 306 itp->it_value = itp->it_interval; 307 itp->it_value.tv_usec -= usec; 308 if (itp->it_value.tv_usec < 0) { 309 itp->it_value.tv_usec += 1000000; 310 itp->it_value.tv_sec--; 311 } 312 } else 313 itp->it_value.tv_usec = 0; /* sec is already 0 */ 314 return (0); 315 } 316 317 /* 318 * Add and subtract routines for timevals. 319 * N.B.: subtract routine doesn't deal with 320 * results which are before the beginning, 321 * it just gets very confused in this case. 322 * Caveat emptor. 323 */ 324 timevaladd(t1, t2) 325 struct timeval *t1, *t2; 326 { 327 328 t1->tv_sec += t2->tv_sec; 329 t1->tv_usec += t2->tv_usec; 330 timevalfix(t1); 331 } 332 333 timevalsub(t1, t2) 334 struct timeval *t1, *t2; 335 { 336 337 t1->tv_sec -= t2->tv_sec; 338 t1->tv_usec -= t2->tv_usec; 339 timevalfix(t1); 340 } 341 342 timevalfix(t1) 343 struct timeval *t1; 344 { 345 346 if (t1->tv_usec < 0) { 347 t1->tv_sec--; 348 t1->tv_usec += 1000000; 349 } 350 if (t1->tv_usec >= 1000000) { 351 t1->tv_sec++; 352 t1->tv_usec -= 1000000; 353 } 354 } 355