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 6.6 (Berkeley) 10/11/85 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 int s; 36 37 s = spl7(); atv = time; splx(s); 38 u.u_error = copyout((caddr_t)&atv, (caddr_t)uap->tp, sizeof (atv)); 39 if (u.u_error) 40 return; 41 if (uap->tzp == 0) 42 return; 43 /* SHOULD HAVE PER-PROCESS TIMEZONE */ 44 u.u_error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, sizeof (tz)); 45 } 46 47 settimeofday() 48 { 49 register struct a { 50 struct timeval *tv; 51 struct timezone *tzp; 52 } *uap = (struct a *)u.u_ap; 53 struct timeval atv; 54 struct timezone atz; 55 56 u.u_error = copyin((caddr_t)uap->tv, (caddr_t)&atv, 57 sizeof (struct timeval)); 58 if (u.u_error) 59 return; 60 setthetime(&atv); 61 if (uap->tzp && suser()) { 62 u.u_error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, 63 sizeof (atz)); 64 if (u.u_error == 0) 65 tz = atz; 66 } 67 } 68 69 setthetime(tv) 70 struct timeval *tv; 71 { 72 int s; 73 74 if (!suser()) 75 return; 76 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 77 boottime.tv_sec += tv->tv_sec - time.tv_sec; 78 s = spl7(); time = *tv; splx(s); 79 resettodr(); 80 } 81 82 int adjtimedelta; 83 extern int tickadj; 84 85 adjtime() 86 { 87 register struct a { 88 struct timeval *delta; 89 struct timeval *olddelta; 90 } *uap = (struct a *)u.u_ap; 91 struct timeval atv, oatv; 92 int s; 93 94 if (!suser()) 95 return; 96 u.u_error = copyin((caddr_t)uap->delta, (caddr_t)&atv, 97 sizeof (struct timeval)); 98 if (u.u_error) 99 return; 100 s = splclock(); 101 if (uap->olddelta) { 102 oatv.tv_sec = adjtimedelta / 1000000; 103 oatv.tv_usec = adjtimedelta % 1000000; 104 (void) copyout((caddr_t)&oatv, (caddr_t)uap->olddelta, 105 sizeof (struct timeval)); 106 } 107 adjtimedelta = atv.tv_sec * 1000000 + atv.tv_usec; 108 if (adjtimedelta % tickadj) 109 adjtimedelta = adjtimedelta / tickadj * tickadj; 110 splx(s); 111 } 112 113 /* 114 * Get value of an interval timer. The process virtual and 115 * profiling virtual time timers are kept in the u. area, since 116 * they can be swapped out. These are kept internally in the 117 * way they are specified externally: in time until they expire. 118 * 119 * The real time interval timer is kept in the process table slot 120 * for the process, and its value (it_value) is kept as an 121 * absolute time rather than as a delta, so that it is easy to keep 122 * periodic real-time signals from drifting. 123 * 124 * Virtual time timers are processed in the hardclock() routine of 125 * kern_clock.c. The real time timer is processed by a timeout 126 * routine, called from the softclock() routine. Since a callout 127 * may be delayed in real time due to interrupt processing in the system, 128 * it is possible for the real time timeout routine (realitexpire, given below), 129 * to be delayed in real time past when it is supposed to occur. It 130 * does not suffice, therefore, to reload the real timer .it_value from the 131 * real time timers .it_interval. Rather, we compute the next time in 132 * absolute time the timer should go off. 133 */ 134 getitimer() 135 { 136 register struct a { 137 u_int which; 138 struct itimerval *itv; 139 } *uap = (struct a *)u.u_ap; 140 struct itimerval aitv; 141 int s; 142 143 if (uap->which > 2) { 144 u.u_error = EINVAL; 145 return; 146 } 147 s = spl7(); 148 if (uap->which == ITIMER_REAL) { 149 /* 150 * Convert from absoulte to relative time in .it_value 151 * part of real time timer. If time for real time timer 152 * has passed return 0, else return difference between 153 * current time and time for the timer to go off. 154 */ 155 aitv = u.u_procp->p_realtimer; 156 if (timerisset(&aitv.it_value)) 157 if (timercmp(&aitv.it_value, &time, <)) 158 timerclear(&aitv.it_value); 159 else 160 timevalsub(&aitv.it_value, &time); 161 } else 162 aitv = u.u_timer[uap->which]; 163 splx(s); 164 u.u_error = copyout((caddr_t)&aitv, (caddr_t)uap->itv, 165 sizeof (struct itimerval)); 166 splx(s); 167 } 168 169 setitimer() 170 { 171 register struct a { 172 u_int which; 173 struct itimerval *itv, *oitv; 174 } *uap = (struct a *)u.u_ap; 175 struct itimerval aitv; 176 int s; 177 register struct proc *p = u.u_procp; 178 179 if (uap->which > 2) { 180 u.u_error = EINVAL; 181 return; 182 } 183 u.u_error = copyin((caddr_t)uap->itv, (caddr_t)&aitv, 184 sizeof (struct itimerval)); 185 if (u.u_error) 186 return; 187 if (uap->oitv) { 188 uap->itv = uap->oitv; 189 getitimer(); 190 } 191 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) { 192 u.u_error = EINVAL; 193 return; 194 } 195 s = spl7(); 196 if (uap->which == ITIMER_REAL) { 197 untimeout(realitexpire, (caddr_t)p); 198 if (timerisset(&aitv.it_value)) { 199 timevaladd(&aitv.it_value, &time); 200 timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); 201 } 202 p->p_realtimer = aitv; 203 } else 204 u.u_timer[uap->which] = aitv; 205 splx(s); 206 } 207 208 /* 209 * Real interval timer expired: 210 * send process whose timer expired an alarm signal. 211 * If time is not set up to reload, then just return. 212 * Else compute next time timer should go off which is > current time. 213 * This is where delay in processing this timeout causes multiple 214 * SIGALRM calls to be compressed into one. 215 */ 216 realitexpire(p) 217 register struct proc *p; 218 { 219 int s; 220 221 psignal(p, SIGALRM); 222 if (!timerisset(&p->p_realtimer.it_interval)) { 223 timerclear(&p->p_realtimer.it_value); 224 return; 225 } 226 for (;;) { 227 s = spl7(); 228 timevaladd(&p->p_realtimer.it_value, 229 &p->p_realtimer.it_interval); 230 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 231 timeout(realitexpire, (caddr_t)p, 232 hzto(&p->p_realtimer.it_value)); 233 splx(s); 234 return; 235 } 236 splx(s); 237 } 238 } 239 240 /* 241 * Check that a proposed value to load into the .it_value or 242 * .it_interval part of an interval timer is acceptable, and 243 * fix it to have at least minimal value (i.e. if it is less 244 * than the resolution of the clock, round it up.) 245 */ 246 itimerfix(tv) 247 struct timeval *tv; 248 { 249 250 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 251 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 252 return (EINVAL); 253 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 254 tv->tv_usec = tick; 255 return (0); 256 } 257 258 /* 259 * Decrement an interval timer by a specified number 260 * of microseconds, which must be less than a second, 261 * i.e. < 1000000. If the timer expires, then reload 262 * it. In this case, carry over (usec - old value) to 263 * reducint the value reloaded into the timer so that 264 * the timer does not drift. This routine assumes 265 * that it is called in a context where the timers 266 * on which it is operating cannot change in value. 267 */ 268 itimerdecr(itp, usec) 269 register struct itimerval *itp; 270 int usec; 271 { 272 273 if (itp->it_value.tv_usec < usec) { 274 if (itp->it_value.tv_sec == 0) { 275 /* expired, and already in next interval */ 276 usec -= itp->it_value.tv_usec; 277 goto expire; 278 } 279 itp->it_value.tv_usec += 1000000; 280 itp->it_value.tv_sec--; 281 } 282 itp->it_value.tv_usec -= usec; 283 usec = 0; 284 if (timerisset(&itp->it_value)) 285 return (1); 286 /* expired, exactly at end of interval */ 287 expire: 288 if (timerisset(&itp->it_interval)) { 289 itp->it_value = itp->it_interval; 290 itp->it_value.tv_usec -= usec; 291 if (itp->it_value.tv_usec < 0) { 292 itp->it_value.tv_usec += 1000000; 293 itp->it_value.tv_sec--; 294 } 295 } else 296 itp->it_value.tv_usec = 0; /* sec is already 0 */ 297 return (0); 298 } 299 300 /* 301 * Add and subtract routines for timevals. 302 * N.B.: subtract routine doesn't deal with 303 * results which are before the beginning, 304 * it just gets very confused in this case. 305 * Caveat emptor. 306 */ 307 timevaladd(t1, t2) 308 struct timeval *t1, *t2; 309 { 310 311 t1->tv_sec += t2->tv_sec; 312 t1->tv_usec += t2->tv_usec; 313 timevalfix(t1); 314 } 315 316 timevalsub(t1, t2) 317 struct timeval *t1, *t2; 318 { 319 320 t1->tv_sec -= t2->tv_sec; 321 t1->tv_usec -= t2->tv_usec; 322 timevalfix(t1); 323 } 324 325 timevalfix(t1) 326 struct timeval *t1; 327 { 328 329 if (t1->tv_usec < 0) { 330 t1->tv_sec--; 331 t1->tv_usec += 1000000; 332 } 333 if (t1->tv_usec >= 1000000) { 334 t1->tv_sec++; 335 t1->tv_usec -= 1000000; 336 } 337 } 338