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/* ntpshmmon.c -- monitor the inner end of an ntpshmwrite.connection
*
* This file is Copyright (c) 2010 by the GPSD project
* BSD terms apply: see the file COPYING in the distribution root for details.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <limits.h>
#include <unistd.h>
#include "gpsd_config.h"
#include "ntpshm.h"
#include "revision.h"
#include "timespec.h"
#define NTPSEGMENTS 256 /* NTPx for x any byte */
static struct shmTime *segments[NTPSEGMENTS + 1];
static struct timespec tick[NTPSEGMENTS + 1];
int main(int argc, char **argv)
{
int option;
int i;
bool killall = false;
bool verbose = false;
int nsamples = INT_MAX;
time_t timeout = (time_t)INT_MAX, starttime = time(NULL);
double cycle = 1.0; /* FIXME, One Sec cycle time a bad assumption */
#define USAGE "usage: ntpshmmon [-s] [-n max] [-t timeout] [-v] [-h] [-V]\n"
while ((option = getopt(argc, argv, "c:hn:st:vV")) != -1) {
switch (option) {
case 'c':
cycle = atof(optarg);
break;
case 'n':
nsamples = atoi(optarg);
break;
case 's':
killall = true;
break;
case 't':
timeout = (time_t)atoi(optarg);
break;
case 'v':
verbose = true;
break;
case 'V':
(void)fprintf(stderr, "%s: version %s (revision %s)\n",
argv[0], VERSION, REVISION);
exit(EXIT_SUCCESS);
case 'h':
default:
fprintf(stderr, USAGE);
break;
}
}
/* grab all segments, keep the non-null ones */
for (i = 0; i < NTPSEGMENTS; i++) {
segments[i] = shm_get(i, false, true);
if (verbose && segments[i] != NULL)
fprintf(stderr, "unit %d opened\n", i);
}
if (killall) {
struct shmTime **pp;
for (pp = segments; pp < segments + NTPSEGMENTS; pp++)
if (*pp != NULL)
(void)shmdt((void *)(*pp));
exit(EXIT_SUCCESS);
}
(void)printf("ntpshmmon version 1\n");
(void)printf("# Name Seen@ Clock Real L Prec\n");
do {
struct shm_stat_t shm_stat;
for (i = 0; i < NTPSEGMENTS; i++) {
long long diff; /* 32 bit long is too short for a timespec */
enum segstat_t status = ntp_read(segments[i], &shm_stat, false);
if (verbose)
fprintf(stderr, "unit %d status %d\n", i, status);
switch(status)
{
case OK:
/* ntpd can slew the clock at 120% real time
* so do not lock out slightly short cycles
* use 50% of cycle time as lock out limit.
* ignore that system time may jump. */
diff = timespec_diff_ns(shm_stat.tvc, tick[i]);
if ( (cycle * 500000000LL) <= diff) {
printf("sample %s %ld.%09ld %ld.%09ld %ld.%09ld %d %3d\n",
ntp_name(i),
(long)shm_stat.tvc.tv_sec, shm_stat.tvc.tv_nsec,
(long)shm_stat.tvr.tv_sec, shm_stat.tvr.tv_nsec,
(long)shm_stat.tvt.tv_sec, shm_stat.tvt.tv_nsec,
shm_stat.leap, shm_stat.precision);
tick[i] = shm_stat.tvc;
--nsamples;
}
break;
case NO_SEGMENT:
break;
case NOT_READY:
/* do nothing, data not ready, wait another cycle */
break;
case BAD_MODE:
fprintf(stderr, "ntpshmmon: unknown mode %d on segment %s\n",
shm_stat.status, ntp_name(i));
break;
case CLASH:
/* do nothing, data is corrupt, wait another cycle */
break;
default:
fprintf(stderr, "ntpshmmon: unknown status %d on segment %s\n",
status, ntp_name(i));
break;
}
}
/*
* Even on a 1 Hz PPS, a sleep(1) may end up
* being sleep(1.1) and missing a beat. Since
* we're ignoring duplicates via timestamp, polling
* at interval < 1 sec shouldn't be a problem.
*/
(void)usleep((useconds_t)(cycle * 1000));
} while
(nsamples != 0 && time(NULL) - starttime < timeout);
exit(EXIT_SUCCESS);
}
/* end */
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