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