1 /* 2 * Copyright (c) 1982 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 6.10 (Berkeley) 05/27/86 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 splx(s); 178 } 179 180 setitimer() 181 { 182 register struct a { 183 u_int which; 184 struct itimerval *itv, *oitv; 185 } *uap = (struct a *)u.u_ap; 186 struct itimerval aitv, *aitvp; 187 int s; 188 register struct proc *p = u.u_procp; 189 190 if (uap->which > 2) { 191 u.u_error = EINVAL; 192 return; 193 } 194 aitvp = uap->itv; 195 if (uap->oitv) { 196 uap->itv = uap->oitv; 197 getitimer(); 198 } 199 if (aitvp == 0) 200 return; 201 u.u_error = copyin((caddr_t)aitvp, (caddr_t)&aitv, 202 sizeof (struct itimerval)); 203 if (u.u_error) 204 return; 205 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) { 206 u.u_error = EINVAL; 207 return; 208 } 209 s = splclock(); 210 if (uap->which == ITIMER_REAL) { 211 untimeout(realitexpire, (caddr_t)p); 212 if (timerisset(&aitv.it_value)) { 213 timevaladd(&aitv.it_value, &time); 214 timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); 215 } 216 p->p_realtimer = aitv; 217 } else 218 u.u_timer[uap->which] = aitv; 219 splx(s); 220 } 221 222 /* 223 * Real interval timer expired: 224 * send process whose timer expired an alarm signal. 225 * If time is not set up to reload, then just return. 226 * Else compute next time timer should go off which is > current time. 227 * This is where delay in processing this timeout causes multiple 228 * SIGALRM calls to be compressed into one. 229 */ 230 realitexpire(p) 231 register struct proc *p; 232 { 233 int s; 234 235 psignal(p, SIGALRM); 236 if (!timerisset(&p->p_realtimer.it_interval)) { 237 timerclear(&p->p_realtimer.it_value); 238 return; 239 } 240 for (;;) { 241 s = splclock(); 242 timevaladd(&p->p_realtimer.it_value, 243 &p->p_realtimer.it_interval); 244 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 245 timeout(realitexpire, (caddr_t)p, 246 hzto(&p->p_realtimer.it_value)); 247 splx(s); 248 return; 249 } 250 splx(s); 251 } 252 } 253 254 /* 255 * Check that a proposed value to load into the .it_value or 256 * .it_interval part of an interval timer is acceptable, and 257 * fix it to have at least minimal value (i.e. if it is less 258 * than the resolution of the clock, round it up.) 259 */ 260 itimerfix(tv) 261 struct timeval *tv; 262 { 263 264 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 265 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 266 return (EINVAL); 267 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 268 tv->tv_usec = tick; 269 return (0); 270 } 271 272 /* 273 * Decrement an interval timer by a specified number 274 * of microseconds, which must be less than a second, 275 * i.e. < 1000000. If the timer expires, then reload 276 * it. In this case, carry over (usec - old value) to 277 * reducint the value reloaded into the timer so that 278 * the timer does not drift. This routine assumes 279 * that it is called in a context where the timers 280 * on which it is operating cannot change in value. 281 */ 282 itimerdecr(itp, usec) 283 register struct itimerval *itp; 284 int usec; 285 { 286 287 if (itp->it_value.tv_usec < usec) { 288 if (itp->it_value.tv_sec == 0) { 289 /* expired, and already in next interval */ 290 usec -= itp->it_value.tv_usec; 291 goto expire; 292 } 293 itp->it_value.tv_usec += 1000000; 294 itp->it_value.tv_sec--; 295 } 296 itp->it_value.tv_usec -= usec; 297 usec = 0; 298 if (timerisset(&itp->it_value)) 299 return (1); 300 /* expired, exactly at end of interval */ 301 expire: 302 if (timerisset(&itp->it_interval)) { 303 itp->it_value = itp->it_interval; 304 itp->it_value.tv_usec -= usec; 305 if (itp->it_value.tv_usec < 0) { 306 itp->it_value.tv_usec += 1000000; 307 itp->it_value.tv_sec--; 308 } 309 } else 310 itp->it_value.tv_usec = 0; /* sec is already 0 */ 311 return (0); 312 } 313 314 /* 315 * Add and subtract routines for timevals. 316 * N.B.: subtract routine doesn't deal with 317 * results which are before the beginning, 318 * it just gets very confused in this case. 319 * Caveat emptor. 320 */ 321 timevaladd(t1, t2) 322 struct timeval *t1, *t2; 323 { 324 325 t1->tv_sec += t2->tv_sec; 326 t1->tv_usec += t2->tv_usec; 327 timevalfix(t1); 328 } 329 330 timevalsub(t1, t2) 331 struct timeval *t1, *t2; 332 { 333 334 t1->tv_sec -= t2->tv_sec; 335 t1->tv_usec -= t2->tv_usec; 336 timevalfix(t1); 337 } 338 339 timevalfix(t1) 340 struct timeval *t1; 341 { 342 343 if (t1->tv_usec < 0) { 344 t1->tv_sec--; 345 t1->tv_usec += 1000000; 346 } 347 if (t1->tv_usec >= 1000000) { 348 t1->tv_sec++; 349 t1->tv_usec -= 1000000; 350 } 351 } 352