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 6.8 (Berkeley) 01/13/86 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 int adjtimedelta; 82 extern int tickadj; 83 84 adjtime() 85 { 86 register struct a { 87 struct timeval *delta; 88 struct timeval *olddelta; 89 } *uap = (struct a *)u.u_ap; 90 struct timeval atv, oatv; 91 int s; 92 93 if (!suser()) 94 return; 95 u.u_error = copyin((caddr_t)uap->delta, (caddr_t)&atv, 96 sizeof (struct timeval)); 97 if (u.u_error) 98 return; 99 s = splclock(); 100 if (uap->olddelta) { 101 oatv.tv_sec = adjtimedelta / 1000000; 102 oatv.tv_usec = adjtimedelta % 1000000; 103 (void) copyout((caddr_t)&oatv, (caddr_t)uap->olddelta, 104 sizeof (struct timeval)); 105 } 106 adjtimedelta = atv.tv_sec * 1000000 + atv.tv_usec; 107 if (adjtimedelta % tickadj) 108 adjtimedelta = adjtimedelta / tickadj * tickadj; 109 splx(s); 110 } 111 112 /* 113 * Get value of an interval timer. The process virtual and 114 * profiling virtual time timers are kept in the u. area, since 115 * they can be swapped out. These are kept internally in the 116 * way they are specified externally: in time until they expire. 117 * 118 * The real time interval timer is kept in the process table slot 119 * for the process, and its value (it_value) is kept as an 120 * absolute time rather than as a delta, so that it is easy to keep 121 * periodic real-time signals from drifting. 122 * 123 * Virtual time timers are processed in the hardclock() routine of 124 * kern_clock.c. The real time timer is processed by a timeout 125 * routine, called from the softclock() routine. Since a callout 126 * may be delayed in real time due to interrupt processing in the system, 127 * it is possible for the real time timeout routine (realitexpire, given below), 128 * to be delayed in real time past when it is supposed to occur. It 129 * does not suffice, therefore, to reload the real timer .it_value from the 130 * real time timers .it_interval. Rather, we compute the next time in 131 * absolute time the timer should go off. 132 */ 133 getitimer() 134 { 135 register struct a { 136 u_int which; 137 struct itimerval *itv; 138 } *uap = (struct a *)u.u_ap; 139 struct itimerval aitv; 140 int s; 141 142 if (uap->which > 2) { 143 u.u_error = EINVAL; 144 return; 145 } 146 s = splclock(); 147 if (uap->which == ITIMER_REAL) { 148 /* 149 * Convert from absoulte to relative time in .it_value 150 * part of real time timer. If time for real time timer 151 * has passed return 0, else return difference between 152 * current time and time for the timer to go off. 153 */ 154 aitv = u.u_procp->p_realtimer; 155 if (timerisset(&aitv.it_value)) 156 if (timercmp(&aitv.it_value, &time, <)) 157 timerclear(&aitv.it_value); 158 else 159 timevalsub(&aitv.it_value, &time); 160 } else 161 aitv = u.u_timer[uap->which]; 162 splx(s); 163 u.u_error = copyout((caddr_t)&aitv, (caddr_t)uap->itv, 164 sizeof (struct itimerval)); 165 splx(s); 166 } 167 168 setitimer() 169 { 170 register struct a { 171 u_int which; 172 struct itimerval *itv, *oitv; 173 } *uap = (struct a *)u.u_ap; 174 struct itimerval aitv, *aitvp; 175 int s; 176 register struct proc *p = u.u_procp; 177 178 if (uap->which > 2) { 179 u.u_error = EINVAL; 180 return; 181 } 182 aitvp = uap->itv; 183 if (uap->oitv) { 184 uap->itv = uap->oitv; 185 getitimer(); 186 } 187 if (aitvp == 0) 188 return; 189 u.u_error = copyin(aitvp, (caddr_t)&aitv, sizeof (struct itimerval)); 190 if (u.u_error) 191 return; 192 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) { 193 u.u_error = EINVAL; 194 return; 195 } 196 s = splclock(); 197 if (uap->which == ITIMER_REAL) { 198 untimeout(realitexpire, (caddr_t)p); 199 if (timerisset(&aitv.it_value)) { 200 timevaladd(&aitv.it_value, &time); 201 timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); 202 } 203 p->p_realtimer = aitv; 204 } else 205 u.u_timer[uap->which] = aitv; 206 splx(s); 207 } 208 209 /* 210 * Real interval timer expired: 211 * send process whose timer expired an alarm signal. 212 * If time is not set up to reload, then just return. 213 * Else compute next time timer should go off which is > current time. 214 * This is where delay in processing this timeout causes multiple 215 * SIGALRM calls to be compressed into one. 216 */ 217 realitexpire(p) 218 register struct proc *p; 219 { 220 int s; 221 222 psignal(p, SIGALRM); 223 if (!timerisset(&p->p_realtimer.it_interval)) { 224 timerclear(&p->p_realtimer.it_value); 225 return; 226 } 227 for (;;) { 228 s = splclock(); 229 timevaladd(&p->p_realtimer.it_value, 230 &p->p_realtimer.it_interval); 231 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 232 timeout(realitexpire, (caddr_t)p, 233 hzto(&p->p_realtimer.it_value)); 234 splx(s); 235 return; 236 } 237 splx(s); 238 } 239 } 240 241 /* 242 * Check that a proposed value to load into the .it_value or 243 * .it_interval part of an interval timer is acceptable, and 244 * fix it to have at least minimal value (i.e. if it is less 245 * than the resolution of the clock, round it up.) 246 */ 247 itimerfix(tv) 248 struct timeval *tv; 249 { 250 251 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 252 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 253 return (EINVAL); 254 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 255 tv->tv_usec = tick; 256 return (0); 257 } 258 259 /* 260 * Decrement an interval timer by a specified number 261 * of microseconds, which must be less than a second, 262 * i.e. < 1000000. If the timer expires, then reload 263 * it. In this case, carry over (usec - old value) to 264 * reducint the value reloaded into the timer so that 265 * the timer does not drift. This routine assumes 266 * that it is called in a context where the timers 267 * on which it is operating cannot change in value. 268 */ 269 itimerdecr(itp, usec) 270 register struct itimerval *itp; 271 int usec; 272 { 273 274 if (itp->it_value.tv_usec < usec) { 275 if (itp->it_value.tv_sec == 0) { 276 /* expired, and already in next interval */ 277 usec -= itp->it_value.tv_usec; 278 goto expire; 279 } 280 itp->it_value.tv_usec += 1000000; 281 itp->it_value.tv_sec--; 282 } 283 itp->it_value.tv_usec -= usec; 284 usec = 0; 285 if (timerisset(&itp->it_value)) 286 return (1); 287 /* expired, exactly at end of interval */ 288 expire: 289 if (timerisset(&itp->it_interval)) { 290 itp->it_value = itp->it_interval; 291 itp->it_value.tv_usec -= usec; 292 if (itp->it_value.tv_usec < 0) { 293 itp->it_value.tv_usec += 1000000; 294 itp->it_value.tv_sec--; 295 } 296 } else 297 itp->it_value.tv_usec = 0; /* sec is already 0 */ 298 return (0); 299 } 300 301 /* 302 * Add and subtract routines for timevals. 303 * N.B.: subtract routine doesn't deal with 304 * results which are before the beginning, 305 * it just gets very confused in this case. 306 * Caveat emptor. 307 */ 308 timevaladd(t1, t2) 309 struct timeval *t1, *t2; 310 { 311 312 t1->tv_sec += t2->tv_sec; 313 t1->tv_usec += t2->tv_usec; 314 timevalfix(t1); 315 } 316 317 timevalsub(t1, t2) 318 struct timeval *t1, *t2; 319 { 320 321 t1->tv_sec -= t2->tv_sec; 322 t1->tv_usec -= t2->tv_usec; 323 timevalfix(t1); 324 } 325 326 timevalfix(t1) 327 struct timeval *t1; 328 { 329 330 if (t1->tv_usec < 0) { 331 t1->tv_sec--; 332 t1->tv_usec += 1000000; 333 } 334 if (t1->tv_usec >= 1000000) { 335 t1->tv_sec++; 336 t1->tv_usec -= 1000000; 337 } 338 } 339