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/*
chronyd/chronyc - Programs for keeping computer clocks accurate.
**********************************************************************
* Copyright (C) Miroslav Lichvar 2009
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
**********************************************************************
=======================================================================
SHM refclock driver.
*/
#include "config.h"
#include "sysincl.h"
#include "refclock.h"
#include "logging.h"
#include "util.h"
#define SHMKEY 0x4e545030
struct shmTime {
int mode; /* 0 - if valid set
* use values,
* clear valid
* 1 - if valid set
* if count before and after read of values is equal,
* use values
* clear valid
*/
volatile int count;
time_t clockTimeStampSec;
int clockTimeStampUSec;
time_t receiveTimeStampSec;
int receiveTimeStampUSec;
int leap;
int precision;
int nsamples;
volatile int valid;
int clockTimeStampNSec;
int receiveTimeStampNSec;
int dummy[8];
};
static int shm_initialise(RCL_Instance instance) {
const char *options[] = {"perm", NULL};
int id, param, perm;
char *s;
struct shmTime *shm;
RCL_CheckDriverOptions(instance, options);
param = atoi(RCL_GetDriverParameter(instance));
s = RCL_GetDriverOption(instance, "perm");
perm = s ? strtol(s, NULL, 8) & 0777 : 0600;
id = shmget(SHMKEY + param, sizeof (struct shmTime), IPC_CREAT | perm);
if (id == -1) {
LOG_FATAL("shmget() failed : %s", strerror(errno));
return 0;
}
shm = (struct shmTime *)shmat(id, 0, 0);
if ((long)shm == -1) {
LOG_FATAL("shmat() failed : %s", strerror(errno));
return 0;
}
RCL_SetDriverData(instance, shm);
return 1;
}
static void shm_finalise(RCL_Instance instance)
{
shmdt(RCL_GetDriverData(instance));
}
static int shm_poll(RCL_Instance instance)
{
struct timespec receive_ts, clock_ts;
struct shmTime t, *shm;
double offset;
shm = (struct shmTime *)RCL_GetDriverData(instance);
t = *shm;
if ((t.mode == 1 && t.count != shm->count) ||
!(t.mode == 0 || t.mode == 1) || !t.valid) {
DEBUG_LOG("SHM sample ignored mode=%d count=%d valid=%d",
t.mode, t.count, t.valid);
return 0;
}
shm->valid = 0;
receive_ts.tv_sec = t.receiveTimeStampSec;
clock_ts.tv_sec = t.clockTimeStampSec;
if (t.clockTimeStampNSec / 1000 == t.clockTimeStampUSec &&
t.receiveTimeStampNSec / 1000 == t.receiveTimeStampUSec) {
receive_ts.tv_nsec = t.receiveTimeStampNSec;
clock_ts.tv_nsec = t.clockTimeStampNSec;
} else {
receive_ts.tv_nsec = 1000 * t.receiveTimeStampUSec;
clock_ts.tv_nsec = 1000 * t.clockTimeStampUSec;
}
UTI_NormaliseTimespec(&clock_ts);
UTI_NormaliseTimespec(&receive_ts);
offset = UTI_DiffTimespecsToDouble(&clock_ts, &receive_ts);
return RCL_AddSample(instance, &receive_ts, offset, t.leap);
}
RefclockDriver RCL_SHM_driver = {
shm_initialise,
shm_finalise,
shm_poll
};
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