1 /* 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)kern_time.c 8.3 (Berkeley) 02/14/95 8 */ 9 10 #include <sys/param.h> 11 #include <sys/resourcevar.h> 12 #include <sys/kernel.h> 13 #include <sys/systm.h> 14 #include <sys/proc.h> 15 #include <sys/vnode.h> 16 17 #include <sys/mount.h> 18 #include <sys/syscallargs.h> 19 20 #include <machine/cpu.h> 21 22 /* 23 * Time of day and interval timer support. 24 * 25 * These routines provide the kernel entry points to get and set 26 * the time-of-day and per-process interval timers. Subroutines 27 * here provide support for adding and subtracting timeval structures 28 * and decrementing interval timers, optionally reloading the interval 29 * timers when they expire. 30 */ 31 32 /* ARGSUSED */ 33 int 34 gettimeofday(p, uap, retval) 35 struct proc *p; 36 register struct gettimeofday_args /* { 37 syscallarg(struct timeval *) tp; 38 syscallarg(struct timezone *) tzp; 39 } */ *uap; 40 register_t *retval; 41 { 42 struct timeval atv; 43 int error = 0; 44 45 if (SCARG(uap, tp)) { 46 microtime(&atv); 47 if (error = copyout((caddr_t)&atv, (caddr_t)SCARG(uap, tp), 48 sizeof (atv))) 49 return (error); 50 } 51 if (SCARG(uap, tzp)) 52 error = copyout((caddr_t)&tz, (caddr_t)SCARG(uap, tzp), 53 sizeof (tz)); 54 return (error); 55 } 56 57 /* ARGSUSED */ 58 int 59 settimeofday(p, uap, retval) 60 struct proc *p; 61 struct settimeofday_args /* { 62 syscallarg(struct timeval *) tv; 63 syscallarg(struct timezone *) tzp; 64 } */ *uap; 65 register_t *retval; 66 { 67 struct timeval atv, delta; 68 struct timezone atz; 69 int error, s; 70 71 if (error = suser(p->p_ucred, &p->p_acflag)) 72 return (error); 73 /* Verify all parameters before changing time. */ 74 if (SCARG(uap, tv) && (error = copyin((caddr_t)SCARG(uap, tv), 75 (caddr_t)&atv, sizeof(atv)))) 76 return (error); 77 if (SCARG(uap, tzp) && (error = copyin((caddr_t)SCARG(uap, tzp), 78 (caddr_t)&atz, sizeof(atz)))) 79 return (error); 80 if (SCARG(uap, tv)) { 81 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 82 s = splclock(); 83 /* nb. delta.tv_usec may be < 0, but this is OK here */ 84 delta.tv_sec = atv.tv_sec - time.tv_sec; 85 delta.tv_usec = atv.tv_usec - time.tv_usec; 86 time = atv; 87 (void) splsoftclock(); 88 timevaladd(&boottime, &delta); 89 timevalfix(&boottime); 90 timevaladd(&runtime, &delta); 91 timevalfix(&runtime); 92 # ifdef NFS 93 lease_updatetime(delta.tv_sec); 94 # endif 95 splx(s); 96 resettodr(); 97 } 98 if (SCARG(uap, tzp)) 99 tz = atz; 100 return (0); 101 } 102 103 extern int tickadj; /* "standard" clock skew, us./tick */ 104 int tickdelta; /* current clock skew, us. per tick */ 105 long timedelta; /* unapplied time correction, us. */ 106 long bigadj = 1000000; /* use 10x skew above bigadj us. */ 107 108 /* ARGSUSED */ 109 int 110 adjtime(p, uap, retval) 111 struct proc *p; 112 register struct adjtime_args /* { 113 syscallarg(struct timeval *) delta; 114 syscallarg(struct timeval *) olddelta; 115 } */ *uap; 116 register_t *retval; 117 { 118 struct timeval atv; 119 register long ndelta, ntickdelta, odelta; 120 int s, error; 121 122 if (error = suser(p->p_ucred, &p->p_acflag)) 123 return (error); 124 if (error = copyin((caddr_t)SCARG(uap, delta), (caddr_t)&atv, 125 sizeof(struct timeval))) 126 return (error); 127 128 /* 129 * Compute the total correction and the rate at which to apply it. 130 * Round the adjustment down to a whole multiple of the per-tick 131 * delta, so that after some number of incremental changes in 132 * hardclock(), tickdelta will become zero, lest the correction 133 * overshoot and start taking us away from the desired final time. 134 */ 135 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 136 if (ndelta > bigadj) 137 ntickdelta = 10 * tickadj; 138 else 139 ntickdelta = tickadj; 140 if (ndelta % ntickdelta) 141 ndelta = ndelta / ntickdelta * ntickdelta; 142 143 /* 144 * To make hardclock()'s job easier, make the per-tick delta negative 145 * if we want time to run slower; then hardclock can simply compute 146 * tick + tickdelta, and subtract tickdelta from timedelta. 147 */ 148 if (ndelta < 0) 149 ntickdelta = -ntickdelta; 150 s = splclock(); 151 odelta = timedelta; 152 timedelta = ndelta; 153 tickdelta = ntickdelta; 154 splx(s); 155 156 if (SCARG(uap, olddelta)) { 157 atv.tv_sec = odelta / 1000000; 158 atv.tv_usec = odelta % 1000000; 159 (void) copyout((caddr_t)&atv, (caddr_t)SCARG(uap, olddelta), 160 sizeof(struct timeval)); 161 } 162 return (0); 163 } 164 165 /* 166 * Get value of an interval timer. The process virtual and 167 * profiling virtual time timers are kept in the p_stats area, since 168 * they can be swapped out. These are kept internally in the 169 * way they are specified externally: in time until they expire. 170 * 171 * The real time interval timer is kept in the process table slot 172 * for the process, and its value (it_value) is kept as an 173 * absolute time rather than as a delta, so that it is easy to keep 174 * periodic real-time signals from drifting. 175 * 176 * Virtual time timers are processed in the hardclock() routine of 177 * kern_clock.c. The real time timer is processed by a timeout 178 * routine, called from the softclock() routine. Since a callout 179 * may be delayed in real time due to interrupt processing in the system, 180 * it is possible for the real time timeout routine (realitexpire, given below), 181 * to be delayed in real time past when it is supposed to occur. It 182 * does not suffice, therefore, to reload the real timer .it_value from the 183 * real time timers .it_interval. Rather, we compute the next time in 184 * absolute time the timer should go off. 185 */ 186 /* ARGSUSED */ 187 int 188 getitimer(p, uap, retval) 189 struct proc *p; 190 register struct getitimer_args /* { 191 syscallarg(u_int) which; 192 syscallarg(struct itimerval *) itv; 193 } */ *uap; 194 register_t *retval; 195 { 196 struct itimerval aitv; 197 int s; 198 199 if (SCARG(uap, which) > ITIMER_PROF) 200 return (EINVAL); 201 s = splclock(); 202 if (SCARG(uap, which) == ITIMER_REAL) { 203 /* 204 * Convert from absolute to relative time in .it_value 205 * part of real time timer. If time for real time timer 206 * has passed return 0, else return difference between 207 * current time and time for the timer to go off. 208 */ 209 aitv = p->p_realtimer; 210 if (timerisset(&aitv.it_value)) 211 if (timercmp(&aitv.it_value, &time, <)) 212 timerclear(&aitv.it_value); 213 else 214 timevalsub(&aitv.it_value, 215 (struct timeval *)&time); 216 } else 217 aitv = p->p_stats->p_timer[SCARG(uap, which)]; 218 splx(s); 219 return (copyout((caddr_t)&aitv, (caddr_t)SCARG(uap, itv), 220 sizeof (struct itimerval))); 221 } 222 223 /* ARGSUSED */ 224 int 225 setitimer(p, uap, retval) 226 struct proc *p; 227 register struct setitimer_args /* { 228 syscallarg(u_int) which; 229 syscallarg(struct itimerval *) itv; 230 syscallarg(struct itimerval *) oitv; 231 } */ *uap; 232 register_t *retval; 233 { 234 struct itimerval aitv; 235 register struct itimerval *itvp; 236 int s, error; 237 238 if (SCARG(uap, which) > ITIMER_PROF) 239 return (EINVAL); 240 itvp = SCARG(uap, itv); 241 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 242 sizeof(struct itimerval)))) 243 return (error); 244 if ((SCARG(uap, itv) = SCARG(uap, oitv)) && 245 (error = getitimer(p, uap, retval))) 246 return (error); 247 if (itvp == 0) 248 return (0); 249 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) 250 return (EINVAL); 251 s = splclock(); 252 if (SCARG(uap, which) == ITIMER_REAL) { 253 untimeout(realitexpire, (caddr_t)p); 254 if (timerisset(&aitv.it_value)) { 255 timevaladd(&aitv.it_value, (struct timeval *)&time); 256 timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); 257 } 258 p->p_realtimer = aitv; 259 } else 260 p->p_stats->p_timer[SCARG(uap, which)] = aitv; 261 splx(s); 262 return (0); 263 } 264 265 /* 266 * Real interval timer expired: 267 * send process whose timer expired an alarm signal. 268 * If time is not set up to reload, then just return. 269 * Else compute next time timer should go off which is > current time. 270 * This is where delay in processing this timeout causes multiple 271 * SIGALRM calls to be compressed into one. 272 */ 273 void 274 realitexpire(arg) 275 void *arg; 276 { 277 register struct proc *p; 278 int s; 279 280 p = (struct proc *)arg; 281 psignal(p, SIGALRM); 282 if (!timerisset(&p->p_realtimer.it_interval)) { 283 timerclear(&p->p_realtimer.it_value); 284 return; 285 } 286 for (;;) { 287 s = splclock(); 288 timevaladd(&p->p_realtimer.it_value, 289 &p->p_realtimer.it_interval); 290 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 291 timeout(realitexpire, (caddr_t)p, 292 hzto(&p->p_realtimer.it_value)); 293 splx(s); 294 return; 295 } 296 splx(s); 297 } 298 } 299 300 /* 301 * Check that a proposed value to load into the .it_value or 302 * .it_interval part of an interval timer is acceptable, and 303 * fix it to have at least minimal value (i.e. if it is less 304 * than the resolution of the clock, round it up.) 305 */ 306 int 307 itimerfix(tv) 308 struct timeval *tv; 309 { 310 311 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 312 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 313 return (EINVAL); 314 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 315 tv->tv_usec = tick; 316 return (0); 317 } 318 319 /* 320 * Decrement an interval timer by a specified number 321 * of microseconds, which must be less than a second, 322 * i.e. < 1000000. If the timer expires, then reload 323 * it. In this case, carry over (usec - old value) to 324 * reduce the value reloaded into the timer so that 325 * the timer does not drift. This routine assumes 326 * that it is called in a context where the timers 327 * on which it is operating cannot change in value. 328 */ 329 int 330 itimerdecr(itp, usec) 331 register struct itimerval *itp; 332 int usec; 333 { 334 335 if (itp->it_value.tv_usec < usec) { 336 if (itp->it_value.tv_sec == 0) { 337 /* expired, and already in next interval */ 338 usec -= itp->it_value.tv_usec; 339 goto expire; 340 } 341 itp->it_value.tv_usec += 1000000; 342 itp->it_value.tv_sec--; 343 } 344 itp->it_value.tv_usec -= usec; 345 usec = 0; 346 if (timerisset(&itp->it_value)) 347 return (1); 348 /* expired, exactly at end of interval */ 349 expire: 350 if (timerisset(&itp->it_interval)) { 351 itp->it_value = itp->it_interval; 352 itp->it_value.tv_usec -= usec; 353 if (itp->it_value.tv_usec < 0) { 354 itp->it_value.tv_usec += 1000000; 355 itp->it_value.tv_sec--; 356 } 357 } else 358 itp->it_value.tv_usec = 0; /* sec is already 0 */ 359 return (0); 360 } 361 362 /* 363 * Add and subtract routines for timevals. 364 * N.B.: subtract routine doesn't deal with 365 * results which are before the beginning, 366 * it just gets very confused in this case. 367 * Caveat emptor. 368 */ 369 timevaladd(t1, t2) 370 struct timeval *t1, *t2; 371 { 372 373 t1->tv_sec += t2->tv_sec; 374 t1->tv_usec += t2->tv_usec; 375 timevalfix(t1); 376 } 377 378 timevalsub(t1, t2) 379 struct timeval *t1, *t2; 380 { 381 382 t1->tv_sec -= t2->tv_sec; 383 t1->tv_usec -= t2->tv_usec; 384 timevalfix(t1); 385 } 386 387 timevalfix(t1) 388 struct timeval *t1; 389 { 390 391 if (t1->tv_usec < 0) { 392 t1->tv_sec--; 393 t1->tv_usec += 1000000; 394 } 395 if (t1->tv_usec >= 1000000) { 396 t1->tv_sec++; 397 t1->tv_usec -= 1000000; 398 } 399 } 400