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/*
* ntpshm.c - put time information in SHM segment for xntpd
* struct shmTime and getShmTime from file in the xntp distribution:
*/
#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include "gpsd.h"
#ifdef NTPSHM_ENABLE
#if defined(HAVE_SYS_TIME_H)
#include <sys/time.h>
#endif
#include <sys/ipc.h>
#include <sys/shm.h>
#define NTPD_BASE 0x4e545030 /* "NTP0" */
#define SHM_UNIT 0 /* SHM driver unit number (0..3) */
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
*/
int count;
time_t clockTimeStampSec;
int clockTimeStampUSec;
time_t receiveTimeStampSec;
int receiveTimeStampUSec;
int leap;
int precision;
int nsamples;
int valid;
int pad[10];
};
static struct shmTime *getShmTime(int unit)
{
int shmid=shmget (NTPD_BASE+unit, sizeof (struct shmTime), IPC_CREAT|0700);
if (shmid == -1) {
gpsd_report(1, "shmget failed\n");
return NULL;
} else {
struct shmTime *p=(struct shmTime *)shmat (shmid, 0, 0);
if ((int)(long)p == -1) {
gpsd_report(1, "shmat failed\n");
p=0;
}
return p;
}
}
int ntpshm_init(struct gps_context_t *context)
{
if ((context->shmTime = getShmTime(SHM_UNIT)) == NULL)
return 0;
memset((void *)context->shmTime,0,sizeof(struct shmTime));
context->shmTime->mode = 1;
return 1;
}
int ntpshm_put(struct gps_context_t *context, double fixtime)
{
struct timeval tv;
double seconds,microseconds;
if (context->shmTime == NULL)
return 0;
gettimeofday(&tv,NULL);
microseconds = 1000000.0 * modf(fixtime,&seconds);
context->shmTime->count++;
context->shmTime->clockTimeStampSec = seconds;
context->shmTime->clockTimeStampUSec = microseconds;
context->shmTime->receiveTimeStampSec = tv.tv_sec;
context->shmTime->receiveTimeStampUSec = tv.tv_usec;
context->shmTime->precision = -1; /* this needs work */
context->shmTime->count++;
context->shmTime->valid = 1;
return 1;
}
#endif /* defined(SHM_H) && defined(IPC_H) */
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