gems-kernel/source/THIRDPARTY/xnu/bsd/kern/kern_ntptime.c
2024-06-03 11:29:39 -05:00

836 lines
24 KiB
C

/*-
***********************************************************************
* *
* Copyright (c) David L. Mills 1993-2001 *
* *
* Permission to use, copy, modify, and distribute this software and *
* its documentation for any purpose and without fee is hereby *
* granted, provided that the above copyright notice appears in all *
* copies and that both the copyright notice and this permission *
* notice appear in supporting documentation, and that the name *
* University of Delaware not be used in advertising or publicity *
* pertaining to distribution of the software without specific, *
* written prior permission. The University of Delaware makes no *
* representations about the suitability this software for any *
* purpose. It is provided "as is" without express or implied *
* warranty. *
* *
**********************************************************************/
/*
* Adapted from the original sources for FreeBSD and timecounters by:
* Poul-Henning Kamp <phk@FreeBSD.org>.
*
* The 32bit version of the "LP" macros seems a bit past its "sell by"
* date so I have retained only the 64bit version and included it directly
* in this file.
*
* Only minor changes done to interface with the timecounters over in
* sys/kern/kern_clock.c. Some of the comments below may be (even more)
* confusing and/or plain wrong in that context.
*/
/*
* Copyright (c) 2017 Apple Computer, Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/time.h>
#include <sys/timex.h>
#include <kern/clock.h>
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/kauth.h>
#include <kern/thread_call.h>
#include <kern/timer_call.h>
#include <machine/machine_routines.h>
#if CONFIG_MACF
#include <security/mac_framework.h>
#endif
#include <IOKit/IOBSD.h>
#include <os/log.h>
typedef int64_t l_fp;
#define L_ADD(v, u) ((v) += (u))
#define L_SUB(v, u) ((v) -= (u))
#define L_ADDHI(v, a) ((v) += (int64_t)(a) << 32)
#define L_NEG(v) ((v) = -(v))
#define L_RSHIFT(v, n) \
do { \
if ((v) < 0) \
(v) = -(-(v) >> (n)); \
else \
(v) = (v) >> (n); \
} while (0)
#define L_MPY(v, a) ((v) *= (a))
#define L_CLR(v) ((v) = 0)
#define L_ISNEG(v) ((v) < 0)
#define L_LINT(v, a) \
do { \
if ((a) > 0) \
((v) = (int64_t)(a) << 32); \
else \
((v) = -((int64_t)(-(a)) << 32)); \
} while (0)
#define L_GINT(v) ((v) < 0 ? -(-(v) >> 32) : (v) >> 32)
/*
* Generic NTP kernel interface
*
* These routines constitute the Network Time Protocol (NTP) interfaces
* for user and daemon application programs. The ntp_gettime() routine
* provides the time, maximum error (synch distance) and estimated error
* (dispersion) to client user application programs. The ntp_adjtime()
* routine is used by the NTP daemon to adjust the calendar clock to an
* externally derived time. The time offset and related variables set by
* this routine are used by other routines in this module to adjust the
* phase and frequency of the clock discipline loop which controls the
* system clock.
*
* When the kernel time is reckoned directly in nanoseconds (NTP_NANO
* defined), the time at each tick interrupt is derived directly from
* the kernel time variable. When the kernel time is reckoned in
* microseconds, (NTP_NANO undefined), the time is derived from the
* kernel time variable together with a variable representing the
* leftover nanoseconds at the last tick interrupt. In either case, the
* current nanosecond time is reckoned from these values plus an
* interpolated value derived by the clock routines in another
* architecture-specific module. The interpolation can use either a
* dedicated counter or a processor cycle counter (PCC) implemented in
* some architectures.
*
*/
/*
* Phase/frequency-lock loop (PLL/FLL) definitions
*
* The nanosecond clock discipline uses two variable types, time
* variables and frequency variables. Both types are represented as 64-
* bit fixed-point quantities with the decimal point between two 32-bit
* halves. On a 32-bit machine, each half is represented as a single
* word and mathematical operations are done using multiple-precision
* arithmetic. On a 64-bit machine, ordinary computer arithmetic is
* used.
*
* A time variable is a signed 64-bit fixed-point number in ns and
* fraction. It represents the remaining time offset to be amortized
* over succeeding tick interrupts. The maximum time offset is about
* 0.5 s and the resolution is about 2.3e-10 ns.
*
* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |s s s| ns |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | fraction |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* A frequency variable is a signed 64-bit fixed-point number in ns/s
* and fraction. It represents the ns and fraction to be added to the
* kernel time variable at each second. The maximum frequency offset is
* about +-500000 ns/s and the resolution is about 2.3e-10 ns/s.
*
* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |s s s s s s s s s s s s s| ns/s |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | fraction |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
#define SHIFT_PLL 4
#define SHIFT_FLL 2
static int time_state = TIME_OK;
int time_status = STA_UNSYNC;
static long time_tai;
static long time_constant;
static long time_precision = 1;
static long time_maxerror = MAXPHASE / 1000;
static unsigned long last_time_maxerror_update;
long time_esterror = MAXPHASE / 1000;
static long time_reftime;
static l_fp time_offset;
static l_fp time_freq;
static int64_t time_adjtime;
static int updated;
static LCK_GRP_DECLARE(ntp_lock_grp, "ntp_lock");
static LCK_SPIN_DECLARE(ntp_lock, &ntp_lock_grp);
#define NTP_LOCK(enable) \
enable = ml_set_interrupts_enabled(FALSE); \
lck_spin_lock(&ntp_lock);
#define NTP_UNLOCK(enable) \
lck_spin_unlock(&ntp_lock);\
ml_set_interrupts_enabled(enable);
#define NTP_ASSERT_LOCKED() LCK_SPIN_ASSERT(&ntp_lock, LCK_ASSERT_OWNED)
static timer_call_data_t ntp_loop_update;
static uint64_t ntp_loop_deadline;
static uint32_t ntp_loop_active;
static uint32_t ntp_loop_period;
#define NTP_LOOP_PERIOD_INTERVAL (NSEC_PER_SEC) /*1 second interval*/
void ntp_init(void);
static void hardupdate(long offset);
static void ntp_gettime1(struct ntptimeval *ntvp);
static bool ntp_is_time_error(int tsl);
static void ntp_loop_update_call(void);
static void refresh_ntp_loop(void);
static void start_ntp_loop(void);
#if DEVELOPMENT || DEBUG
uint32_t g_should_log_clock_adjustments = 0;
SYSCTL_INT(_kern, OID_AUTO, log_clock_adjustments, CTLFLAG_RW | CTLFLAG_LOCKED, &g_should_log_clock_adjustments, 0, "enable kernel clock adjustment logging");
#endif
static bool
ntp_is_time_error(int tsl)
{
if (tsl & (STA_UNSYNC | STA_CLOCKERR)) {
return true;
}
return false;
}
static void
ntp_gettime1(struct ntptimeval *ntvp)
{
struct timespec atv;
NTP_ASSERT_LOCKED();
nanotime(&atv);
ntvp->time.tv_sec = atv.tv_sec;
ntvp->time.tv_nsec = atv.tv_nsec;
if ((unsigned long)atv.tv_sec > last_time_maxerror_update) {
time_maxerror += (MAXFREQ / 1000) * (atv.tv_sec - last_time_maxerror_update);
last_time_maxerror_update = atv.tv_sec;
}
ntvp->maxerror = time_maxerror;
ntvp->esterror = time_esterror;
ntvp->tai = time_tai;
ntvp->time_state = time_state;
if (ntp_is_time_error(time_status)) {
ntvp->time_state = TIME_ERROR;
}
}
int
ntp_gettime(struct proc *p, struct ntp_gettime_args *uap, __unused int32_t *retval)
{
struct ntptimeval ntv;
int error;
boolean_t enable;
NTP_LOCK(enable);
ntp_gettime1(&ntv);
NTP_UNLOCK(enable);
if (IS_64BIT_PROCESS(p)) {
struct user64_ntptimeval user_ntv = {};
user_ntv.time.tv_sec = ntv.time.tv_sec;
user_ntv.time.tv_nsec = ntv.time.tv_nsec;
user_ntv.maxerror = ntv.maxerror;
user_ntv.esterror = ntv.esterror;
user_ntv.tai = ntv.tai;
user_ntv.time_state = ntv.time_state;
error = copyout(&user_ntv, uap->ntvp, sizeof(user_ntv));
} else {
struct user32_ntptimeval user_ntv = {};
user_ntv.time.tv_sec = (user32_long_t)ntv.time.tv_sec;
user_ntv.time.tv_nsec = (user32_long_t)ntv.time.tv_nsec;
user_ntv.maxerror = (user32_long_t)ntv.maxerror;
user_ntv.esterror = (user32_long_t)ntv.esterror;
user_ntv.tai = (user32_long_t)ntv.tai;
user_ntv.time_state = ntv.time_state;
error = copyout(&user_ntv, uap->ntvp, sizeof(user_ntv));
}
if (error) {
return error;
}
return ntv.time_state;
}
int
ntp_adjtime(struct proc *p, struct ntp_adjtime_args *uap, int32_t *retval)
{
struct timex ntv = {};
long freq;
unsigned int modes;
int error, ret = 0;
clock_sec_t sec;
clock_usec_t microsecs;
boolean_t enable;
if (IS_64BIT_PROCESS(p)) {
struct user64_timex user_ntv;
error = copyin(uap->tp, &user_ntv, sizeof(user_ntv));
ntv.modes = user_ntv.modes;
ntv.offset = (long)user_ntv.offset;
ntv.freq = (long)user_ntv.freq;
ntv.maxerror = (long)user_ntv.maxerror;
ntv.esterror = (long)user_ntv.esterror;
ntv.status = user_ntv.status;
ntv.constant = (long)user_ntv.constant;
ntv.precision = (long)user_ntv.precision;
ntv.tolerance = (long)user_ntv.tolerance;
} else {
struct user32_timex user_ntv;
error = copyin(uap->tp, &user_ntv, sizeof(user_ntv));
ntv.modes = user_ntv.modes;
ntv.offset = user_ntv.offset;
ntv.freq = user_ntv.freq;
ntv.maxerror = user_ntv.maxerror;
ntv.esterror = user_ntv.esterror;
ntv.status = user_ntv.status;
ntv.constant = user_ntv.constant;
ntv.precision = user_ntv.precision;
ntv.tolerance = user_ntv.tolerance;
}
if (error) {
return error;
}
#if DEVELOPMENT || DEBUG
if (g_should_log_clock_adjustments) {
os_log(OS_LOG_DEFAULT, "%s: BEFORE modes %u offset %ld freq %ld status %d constant %ld time_adjtime %lld\n",
__func__, ntv.modes, ntv.offset, ntv.freq, ntv.status, ntv.constant, time_adjtime);
}
#endif
/*
* Update selected clock variables - only the superuser can
* change anything. Note that there is no error checking here on
* the assumption the superuser should know what it is doing.
* Note that either the time constant or TAI offset are loaded
* from the ntv.constant member, depending on the mode bits. If
* the STA_PLL bit in the status word is cleared, the state and
* status words are reset to the initial values at boot.
*/
modes = ntv.modes;
if (modes) {
/* Check that this task is entitled to set the time or it is root */
if (!IOCurrentTaskHasEntitlement(SETTIME_ENTITLEMENT)) {
#if CONFIG_MACF
error = mac_system_check_settime(kauth_cred_get());
if (error) {
return error;
}
#endif
if ((error = priv_check_cred(kauth_cred_get(), PRIV_ADJTIME, 0))) {
return error;
}
}
}
NTP_LOCK(enable);
if (modes & MOD_MAXERROR) {
clock_gettimeofday(&sec, &microsecs);
time_maxerror = ntv.maxerror;
last_time_maxerror_update = sec;
}
if (modes & MOD_ESTERROR) {
time_esterror = ntv.esterror;
}
if (modes & MOD_STATUS) {
if (time_status & STA_PLL && !(ntv.status & STA_PLL)) {
time_state = TIME_OK;
time_status = STA_UNSYNC;
}
time_status &= STA_RONLY;
time_status |= ntv.status & ~STA_RONLY;
/*
* Nor PPS or leaps seconds are supported.
* Filter out unsupported bits.
*/
time_status &= STA_SUPPORTED;
}
if (modes & MOD_TIMECONST) {
if (ntv.constant < 0) {
time_constant = 0;
} else if (ntv.constant > MAXTC) {
time_constant = MAXTC;
} else {
time_constant = ntv.constant;
}
}
if (modes & MOD_TAI) {
if (ntv.constant > 0) {
time_tai = ntv.constant;
}
}
if (modes & MOD_NANO) {
time_status |= STA_NANO;
}
if (modes & MOD_MICRO) {
time_status &= ~STA_NANO;
}
if (modes & MOD_CLKB) {
time_status |= STA_CLK;
}
if (modes & MOD_CLKA) {
time_status &= ~STA_CLK;
}
if (modes & MOD_FREQUENCY) {
freq = (ntv.freq * 1000LL) >> 16;
if (freq > MAXFREQ) {
L_LINT(time_freq, MAXFREQ);
} else if (freq < -MAXFREQ) {
L_LINT(time_freq, -MAXFREQ);
} else {
/*
* ntv.freq is [PPM * 2^16] = [us/s * 2^16]
* time_freq is [ns/s * 2^32]
*/
time_freq = ntv.freq * 1000LL * 65536LL;
}
}
if (modes & MOD_OFFSET) {
if (time_status & STA_NANO) {
hardupdate(ntv.offset);
} else {
hardupdate(ntv.offset * 1000);
}
}
ret = ntp_is_time_error(time_status) ? TIME_ERROR : time_state;
#if DEVELOPMENT || DEBUG
if (g_should_log_clock_adjustments) {
os_log(OS_LOG_DEFAULT, "%s: AFTER modes %u offset %lld freq %lld status %d constant %ld time_adjtime %lld\n",
__func__, modes, time_offset, time_freq, time_status, time_constant, time_adjtime);
}
#endif
/*
* Retrieve all clock variables. Note that the TAI offset is
* returned only by ntp_gettime();
*/
if (IS_64BIT_PROCESS(p)) {
struct user64_timex user_ntv = {};
user_ntv.modes = modes;
if (time_status & STA_NANO) {
user_ntv.offset = L_GINT(time_offset);
} else {
user_ntv.offset = L_GINT(time_offset) / 1000;
}
if (time_freq > 0) {
user_ntv.freq = L_GINT(((int64_t)(time_freq / 1000LL)) << 16);
} else {
user_ntv.freq = -L_GINT(((int64_t)(-(time_freq) / 1000LL)) << 16);
}
user_ntv.maxerror = time_maxerror;
user_ntv.esterror = time_esterror;
user_ntv.status = time_status;
user_ntv.constant = time_constant;
if (time_status & STA_NANO) {
user_ntv.precision = time_precision;
} else {
user_ntv.precision = time_precision / 1000;
}
user_ntv.tolerance = MAXFREQ * SCALE_PPM;
/* unlock before copyout */
NTP_UNLOCK(enable);
error = copyout(&user_ntv, uap->tp, sizeof(user_ntv));
} else {
struct user32_timex user_ntv = {};
user_ntv.modes = modes;
if (time_status & STA_NANO) {
user_ntv.offset = L_GINT(time_offset);
} else {
user_ntv.offset = L_GINT(time_offset) / 1000;
}
if (time_freq > 0) {
user_ntv.freq = L_GINT((time_freq / 1000LL) << 16);
} else {
user_ntv.freq = -L_GINT((-(time_freq) / 1000LL) << 16);
}
user_ntv.maxerror = (user32_long_t)time_maxerror;
user_ntv.esterror = (user32_long_t)time_esterror;
user_ntv.status = time_status;
user_ntv.constant = (user32_long_t)time_constant;
if (time_status & STA_NANO) {
user_ntv.precision = (user32_long_t)time_precision;
} else {
user_ntv.precision = (user32_long_t)(time_precision / 1000);
}
user_ntv.tolerance = MAXFREQ * SCALE_PPM;
/* unlock before copyout */
NTP_UNLOCK(enable);
error = copyout(&user_ntv, uap->tp, sizeof(user_ntv));
}
if (modes) {
start_ntp_loop();
}
if (error == 0) {
*retval = ret;
}
return error;
}
int64_t
ntp_get_freq(void)
{
return time_freq;
}
/*
* Compute the adjustment to add to the next second.
*/
void
ntp_update_second(int64_t *adjustment, clock_sec_t secs)
{
int tickrate;
l_fp time_adj;
l_fp ftemp, old_time_adjtime, old_offset;
NTP_ASSERT_LOCKED();
if (secs > last_time_maxerror_update) {
time_maxerror += (MAXFREQ / 1000) * (secs - last_time_maxerror_update);
last_time_maxerror_update = secs;
}
old_offset = time_offset;
old_time_adjtime = time_adjtime;
ftemp = time_offset;
L_RSHIFT(ftemp, SHIFT_PLL + time_constant);
time_adj = ftemp;
L_SUB(time_offset, ftemp);
L_ADD(time_adj, time_freq);
/*
* Apply any correction from adjtime. If more than one second
* off we slew at a rate of 5ms/s (5000 PPM) else 500us/s (500PPM)
* until the last second is slewed the final < 500 usecs.
*/
if (time_adjtime != 0) {
if (time_adjtime > 1000000) {
tickrate = 5000;
} else if (time_adjtime < -1000000) {
tickrate = -5000;
} else if (time_adjtime > 500) {
tickrate = 500;
} else if (time_adjtime < -500) {
tickrate = -500;
} else {
tickrate = (int)time_adjtime;
}
time_adjtime -= tickrate;
L_LINT(ftemp, tickrate * 1000);
L_ADD(time_adj, ftemp);
}
if (old_time_adjtime || ((time_offset || old_offset) && (time_offset != old_offset))) {
updated = 1;
} else {
updated = 0;
}
#if DEVELOPMENT || DEBUG
if (g_should_log_clock_adjustments) {
int64_t nano = (time_adj > 0)? time_adj >> 32 : -((-time_adj) >> 32);
int64_t frac = (time_adj > 0)? ((uint32_t) time_adj) : -((uint32_t) (-time_adj));
os_log(OS_LOG_DEFAULT, "%s:AFTER offset %lld (%lld) freq %lld status %d "
"constant %ld time_adjtime %lld nano %lld frac %lld adj %lld\n",
__func__, time_offset, (time_offset > 0)? time_offset >> 32 : -((-time_offset) >> 32),
time_freq, time_status, time_constant, time_adjtime, nano, frac, time_adj);
}
#endif
*adjustment = time_adj;
}
/*
* hardupdate() - local clock update
*
* This routine is called by ntp_adjtime() when an offset is provided
* to update the local clock phase and frequency.
* The implementation is of an adaptive-parameter, hybrid
* phase/frequency-lock loop (PLL/FLL). The routine computes new
* time and frequency offset estimates for each call.
* Presumably, calls to ntp_adjtime() occur only when the caller
* believes the local clock is valid within some bound (+-128 ms with
* NTP).
*
* For uncompensated quartz crystal oscillators and nominal update
* intervals less than 256 s, operation should be in phase-lock mode,
* where the loop is disciplined to phase. For update intervals greater
* than 1024 s, operation should be in frequency-lock mode, where the
* loop is disciplined to frequency. Between 256 s and 1024 s, the mode
* is selected by the STA_MODE status bit.
*/
static void
hardupdate(long offset)
{
long mtemp = 0;
long time_monitor;
clock_sec_t time_uptime;
l_fp ftemp;
NTP_ASSERT_LOCKED();
if (!(time_status & STA_PLL)) {
return;
}
if (offset > MAXPHASE) {
time_monitor = MAXPHASE;
} else if (offset < -MAXPHASE) {
time_monitor = -MAXPHASE;
} else {
time_monitor = offset;
}
L_LINT(time_offset, time_monitor);
clock_get_calendar_uptime(&time_uptime);
if (time_status & STA_FREQHOLD || time_reftime == 0) {
time_reftime = time_uptime;
}
mtemp = time_uptime - time_reftime;
L_LINT(ftemp, time_monitor);
L_RSHIFT(ftemp, (SHIFT_PLL + 2 + time_constant) << 1);
L_MPY(ftemp, mtemp);
L_ADD(time_freq, ftemp);
time_status &= ~STA_MODE;
if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp >
MAXSEC)) {
if (time_monitor > 0) {
L_LINT(ftemp, (time_monitor << 4) / mtemp);
} else {
L_LINT(ftemp, -((int64_t)(-(time_monitor)) << 4) / mtemp);
}
L_RSHIFT(ftemp, SHIFT_FLL + 4);
L_ADD(time_freq, ftemp);
time_status |= STA_MODE;
}
time_reftime = time_uptime;
if (L_GINT(time_freq) > MAXFREQ) {
L_LINT(time_freq, MAXFREQ);
} else if (L_GINT(time_freq) < -MAXFREQ) {
L_LINT(time_freq, -MAXFREQ);
}
}
static int
kern_adjtime(struct timeval *delta)
{
struct timeval atv;
int64_t ltr, ltw;
boolean_t enable;
if (delta == NULL) {
return EINVAL;
}
ltw = (int64_t)delta->tv_sec * (int64_t)USEC_PER_SEC + delta->tv_usec;
NTP_LOCK(enable);
ltr = time_adjtime;
time_adjtime = ltw;
#if DEVELOPMENT || DEBUG
if (g_should_log_clock_adjustments) {
os_log(OS_LOG_DEFAULT, "%s:AFTER offset %lld freq %lld status %d constant %ld time_adjtime %lld\n",
__func__, time_offset, time_freq, time_status, time_constant, time_adjtime);
}
#endif
NTP_UNLOCK(enable);
atv.tv_sec = (__darwin_time_t)(ltr / (int64_t)USEC_PER_SEC);
atv.tv_usec = ltr % (int64_t)USEC_PER_SEC;
if (atv.tv_usec < 0) {
atv.tv_usec += (suseconds_t)USEC_PER_SEC;
atv.tv_sec--;
}
*delta = atv;
start_ntp_loop();
return 0;
}
int
adjtime(struct proc *p, struct adjtime_args *uap, __unused int32_t *retval)
{
struct timeval atv;
int error;
/* Check that this task is entitled to set the time or it is root */
if (!IOCurrentTaskHasEntitlement(SETTIME_ENTITLEMENT)) {
#if CONFIG_MACF
error = mac_system_check_settime(kauth_cred_get());
if (error) {
return error;
}
#endif
if ((error = priv_check_cred(kauth_cred_get(), PRIV_ADJTIME, 0))) {
return error;
}
}
if (IS_64BIT_PROCESS(p)) {
struct user64_timeval user_atv;
error = copyin(uap->delta, &user_atv, sizeof(user_atv));
atv.tv_sec = (__darwin_time_t)user_atv.tv_sec;
atv.tv_usec = user_atv.tv_usec;
} else {
struct user32_timeval user_atv;
error = copyin(uap->delta, &user_atv, sizeof(user_atv));
atv.tv_sec = user_atv.tv_sec;
atv.tv_usec = user_atv.tv_usec;
}
if (error) {
return error;
}
kern_adjtime(&atv);
if (uap->olddelta) {
if (IS_64BIT_PROCESS(p)) {
struct user64_timeval user_atv = {};
user_atv.tv_sec = atv.tv_sec;
user_atv.tv_usec = atv.tv_usec;
error = copyout(&user_atv, uap->olddelta, sizeof(user_atv));
} else {
struct user32_timeval user_atv = {};
user_atv.tv_sec = (user32_time_t)atv.tv_sec;
user_atv.tv_usec = atv.tv_usec;
error = copyout(&user_atv, uap->olddelta, sizeof(user_atv));
}
}
return error;
}
static void
ntp_loop_update_call(void)
{
boolean_t enable;
NTP_LOCK(enable);
/*
* Update the scale factor used by clock_calend.
* NOTE: clock_update_calendar will call ntp_update_second to compute the next adjustment.
*/
clock_update_calendar();
refresh_ntp_loop();
NTP_UNLOCK(enable);
}
static void
refresh_ntp_loop(void)
{
NTP_ASSERT_LOCKED();
if (--ntp_loop_active == 0) {
/*
* Activate the timer only if the next second adjustment might change.
* ntp_update_second checks it and sets updated accordingly.
*/
if (updated) {
clock_deadline_for_periodic_event(ntp_loop_period, mach_absolute_time(), &ntp_loop_deadline);
if (!timer_call_enter(&ntp_loop_update, ntp_loop_deadline, TIMER_CALL_SYS_CRITICAL)) {
ntp_loop_active++;
}
}
}
}
/*
* This function triggers a timer that each second will calculate the adjustment to
* provide to clock_calendar to scale the time (used by gettimeofday-family syscalls).
* The periodic timer will stop when the adjustment will reach a stable value.
*/
static void
start_ntp_loop(void)
{
boolean_t enable;
NTP_LOCK(enable);
ntp_loop_deadline = mach_absolute_time() + ntp_loop_period;
if (!timer_call_enter(&ntp_loop_update, ntp_loop_deadline, TIMER_CALL_SYS_CRITICAL)) {
ntp_loop_active++;
}
NTP_UNLOCK(enable);
}
static void
init_ntp_loop(void)
{
uint64_t abstime;
ntp_loop_active = 0;
nanoseconds_to_absolutetime(NTP_LOOP_PERIOD_INTERVAL, &abstime);
ntp_loop_period = (uint32_t)abstime;
timer_call_setup(&ntp_loop_update, (timer_call_func_t)ntp_loop_update_call, NULL);
}
void
ntp_init(void)
{
init_ntp_loop();
}