* Copyright (c) 1982, 1986 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
* @(#)kern_time.c 7.2 (Berkeley) %G%
#include "../machine/reg.h"
#include "dir.h" /* XXX */
* Time of day and interval timer support.
* These routines provide the kernel entry points to get and set
* the time-of-day and per-process interval timers. Subroutines
* here provide support for adding and subtracting timeval structures
* and decrementing interval timers, optionally reloading the interval
* timers when they expire.
} *uap
= (struct a
*)u
.u_ap
;
u
.u_error
= copyout((caddr_t
)&atv
, (caddr_t
)uap
->tp
, sizeof (atv
));
/* SHOULD HAVE PER-PROCESS TIMEZONE */
u
.u_error
= copyout((caddr_t
)&tz
, (caddr_t
)uap
->tzp
, sizeof (tz
));
} *uap
= (struct a
*)u
.u_ap
;
u
.u_error
= copyin((caddr_t
)uap
->tv
, (caddr_t
)&atv
,
sizeof (struct timeval
));
if (uap
->tzp
&& suser()) {
u
.u_error
= copyin((caddr_t
)uap
->tzp
, (caddr_t
)&atz
,
/* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */
boottime
.tv_sec
+= tv
->tv_sec
- time
.tv_sec
;
s
= splhigh(); time
= *tv
; splx(s
);
extern int tickadj
; /* "standard" clock skew, us./tick */
int tickdelta
; /* current clock skew, us. per tick */
long timedelta
; /* unapplied time correction, us. */
long bigadj
= 1000000; /* use 10x skew above bigadj us. */
struct timeval
*olddelta
;
} *uap
= (struct a
*)u
.u_ap
;
struct timeval atv
, oatv
;
u
.u_error
= copyin((caddr_t
)uap
->delta
, (caddr_t
)&atv
,
sizeof (struct timeval
));
ndelta
= atv
.tv_sec
* 1000000 + atv
.tv_usec
;
tickdelta
= 10 * tickadj
;
ndelta
= ndelta
/ tickadj
* tickadj
;
oatv
.tv_sec
= timedelta
/ 1000000;
oatv
.tv_usec
= timedelta
% 1000000;
(void) copyout((caddr_t
)&oatv
, (caddr_t
)uap
->olddelta
,
sizeof (struct timeval
));
* Get value of an interval timer. The process virtual and
* profiling virtual time timers are kept in the u. area, since
* they can be swapped out. These are kept internally in the
* way they are specified externally: in time until they expire.
* The real time interval timer is kept in the process table slot
* for the process, and its value (it_value) is kept as an
* absolute time rather than as a delta, so that it is easy to keep
* periodic real-time signals from drifting.
* Virtual time timers are processed in the hardclock() routine of
* kern_clock.c. The real time timer is processed by a timeout
* routine, called from the softclock() routine. Since a callout
* may be delayed in real time due to interrupt processing in the system,
* it is possible for the real time timeout routine (realitexpire, given below),
* to be delayed in real time past when it is supposed to occur. It
* does not suffice, therefore, to reload the real timer .it_value from the
* real time timers .it_interval. Rather, we compute the next time in
* absolute time the timer should go off.
} *uap
= (struct a
*)u
.u_ap
;
if (uap
->which
== ITIMER_REAL
) {
* Convert from absoulte to relative time in .it_value
* part of real time timer. If time for real time timer
* has passed return 0, else return difference between
* current time and time for the timer to go off.
aitv
= u
.u_procp
->p_realtimer
;
if (timerisset(&aitv
.it_value
))
if (timercmp(&aitv
.it_value
, &time
, <))
timerclear(&aitv
.it_value
);
timevalsub(&aitv
.it_value
, &time
);
aitv
= u
.u_timer
[uap
->which
];
u
.u_error
= copyout((caddr_t
)&aitv
, (caddr_t
)uap
->itv
,
sizeof (struct itimerval
));
struct itimerval
*itv
, *oitv
;
} *uap
= (struct a
*)u
.u_ap
;
struct itimerval aitv
, *aitvp
;
register struct proc
*p
= u
.u_procp
;
u
.u_error
= copyin((caddr_t
)aitvp
, (caddr_t
)&aitv
,
sizeof (struct itimerval
));
if (itimerfix(&aitv
.it_value
) || itimerfix(&aitv
.it_interval
)) {
if (uap
->which
== ITIMER_REAL
) {
untimeout(realitexpire
, (caddr_t
)p
);
if (timerisset(&aitv
.it_value
)) {
timevaladd(&aitv
.it_value
, &time
);
timeout(realitexpire
, (caddr_t
)p
, hzto(&aitv
.it_value
));
u
.u_timer
[uap
->which
] = aitv
;
* Real interval timer expired:
* send process whose timer expired an alarm signal.
* If time is not set up to reload, then just return.
* Else compute next time timer should go off which is > current time.
* This is where delay in processing this timeout causes multiple
* SIGALRM calls to be compressed into one.
if (!timerisset(&p
->p_realtimer
.it_interval
)) {
timerclear(&p
->p_realtimer
.it_value
);
timevaladd(&p
->p_realtimer
.it_value
,
&p
->p_realtimer
.it_interval
);
if (timercmp(&p
->p_realtimer
.it_value
, &time
, >)) {
timeout(realitexpire
, (caddr_t
)p
,
hzto(&p
->p_realtimer
.it_value
));
* Check that a proposed value to load into the .it_value or
* .it_interval part of an interval timer is acceptable, and
* fix it to have at least minimal value (i.e. if it is less
* than the resolution of the clock, round it up.)
if (tv
->tv_sec
< 0 || tv
->tv_sec
> 100000000 ||
tv
->tv_usec
< 0 || tv
->tv_usec
>= 1000000)
if (tv
->tv_sec
== 0 && tv
->tv_usec
!= 0 && tv
->tv_usec
< tick
)
* Decrement an interval timer by a specified number
* of microseconds, which must be less than a second,
* i.e. < 1000000. If the timer expires, then reload
* it. In this case, carry over (usec - old value) to
* reducint the value reloaded into the timer so that
* the timer does not drift. This routine assumes
* that it is called in a context where the timers
* on which it is operating cannot change in value.
register struct itimerval
*itp
;
if (itp
->it_value
.tv_usec
< usec
) {
if (itp
->it_value
.tv_sec
== 0) {
/* expired, and already in next interval */
usec
-= itp
->it_value
.tv_usec
;
itp
->it_value
.tv_usec
+= 1000000;
itp
->it_value
.tv_usec
-= usec
;
if (timerisset(&itp
->it_value
))
/* expired, exactly at end of interval */
if (timerisset(&itp
->it_interval
)) {
itp
->it_value
= itp
->it_interval
;
itp
->it_value
.tv_usec
-= usec
;
if (itp
->it_value
.tv_usec
< 0) {
itp
->it_value
.tv_usec
+= 1000000;
itp
->it_value
.tv_usec
= 0; /* sec is already 0 */
* Add and subtract routines for timevals.
* N.B.: subtract routine doesn't deal with
* results which are before the beginning,
* it just gets very confused in this case.
t1
->tv_sec
+= t2
->tv_sec
;
t1
->tv_usec
+= t2
->tv_usec
;
t1
->tv_sec
-= t2
->tv_sec
;
t1
->tv_usec
-= t2
->tv_usec
;
if (t1
->tv_usec
>= 1000000) {