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/*
* Written by Tzafrir Cohen <tzafrir.cohen@xorcom.com>
* Copyright (C) 2006, Xorcom
*
* Derived from zttest.c
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <sys/timex.h>
#include <linux/param.h>
#include <syslog.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/time.h>
#include <sys/signal.h>
#include <math.h>
static const char *rcsid = "$Id$";
#define FREQ_PER_TICK (64*1024)
#define USEC_PER_ZAP_TICK 1000 /* Zaptel tick in usec */
#define USER_HZ 100
#define SYNC_TOLERANCE 100
#define DEFAULT_INTERVAL 60
static const char *program;
static int synced_time; /* time (seconds) we are so far synced */
static int verbose = 0;
static int sync_tolerance = 100;
void usage() {
fprintf(stderr, "%s: synchronize system clock from zaptel clock.\n"
"Version: %s\n"
"\n"
"Usage: %s [ -c COUNT ] [-i INTERVAL] [ -t PERIOD ] [-v]\n"
" %s -h\n"
"\n"
"Options:\n"
" -c only run COUNT cycles of synchronization (default: forever).\n"
" -i set cycle Interval to INTERVAL (in seconds. Default: %d).\n"
" -t sync tolerance to PERIOD (in usec. Default: %d). For debugging.\n"
" -v Be more Verbose\n"
" -h Print this Help text and exit.\n"
"", program, rcsid, program, program, DEFAULT_INTERVAL,
sync_tolerance);
}
/* based on zttest.c */
/*
* Print a message to the log according to the value of synced_time
*
* All parameters are for the "Not Synced" warning message.
* TODO: Find a better way.
*/
void status_message(void) {
if (synced_time == 0)
syslog(LOG_NOTICE, "Not Synced.\n");
else
syslog(LOG_INFO, "Good Sync for %d seconds\n", synced_time);
return;
}
/*
* interval: period, in seconds
* diff_usec: Current offset, in micro-seconds.
*/
int clock_sync(int interval, int diff_usec)
{
struct timex cur_time = {.modes=0}; /* just query */
int diff_tick; /* Difference in adjtimex ticks */
int req_tick; /* Required adjtimex tick value */
long long diff_freq;
long long req_freq;
int usec_left; /* Usec adjusted by frequency */
int ret;
ret = adjtimex(&cur_time);
diff_tick = diff_usec / (interval * USER_HZ);
usec_left = diff_usec - diff_tick * (interval * USER_HZ);
diff_freq = usec_left * FREQ_PER_TICK / interval;
req_tick = cur_time.tick - diff_tick;
req_freq = cur_time.freq - diff_freq;
if(!diff_tick && abs(usec_left) < sync_tolerance)
synced_time += interval;
else
synced_time = 0;
status_message();
if (verbose || !synced_time)
syslog(LOG_INFO, "interval: %d, diff_tick: %d, diff_usec: %d, usec_left: %d.\n",
interval, diff_tick, diff_usec, usec_left);
/* set the clock rate */
cur_time.freq = req_freq;
cur_time.tick = req_tick;
cur_time.modes = ADJ_TICK | ADJ_FREQUENCY;
ret = adjtimex(&cur_time);
if (ret < 0)
syslog(LOG_ERR, "Adjtimex failed to set frequency. New frequency: %lld. Error: %d (%s)\n",
req_freq, errno, strerror(errno));
return 0;
}
static int pass = 0;
void hup_handler(int sig)
{
if (verbose > 0) {
syslog(LOG_INFO, "--- Results after %d passes ---\n", pass);
status_message();
}
closelog();
exit(0);
}
void sigusr1_handler(int sig) {
verbose++;
syslog(LOG_INFO, "Increased verbosity to %d (increase: SIGUSR1, reset: SIGUSR2).\n", verbose);
status_message();
}
void sigusr2_handler(int sig) {
verbose = 0;
syslog(LOG_INFO, "Set verbosity to 0 (increase: SIGUSR1, reset: SIGUSR2).\n");
}
void sync_cycle(int fd, int interval)
{
char buf[1024]; /* TODO: why 1024 and not 1000? */
struct timeval start;
struct timeval end;
long long usec;
int count = 0;
int i;
int res;
gettimeofday(&start, NULL);
for (i=0; i < interval*8; i++) {
res = read(fd, buf, sizeof(buf));
if (res < 0) {
syslog(LOG_ERR, "Failed to read from pseudo interface: %s\n", strerror(errno));
exit(1);
}
count += res/8;
}
gettimeofday(&end, NULL);
/* time difference in microseconds: */
usec = (end.tv_sec - start.tv_sec) * 1000000;
usec += end.tv_usec - start.tv_usec;
clock_sync(interval, usec - (count * USEC_PER_ZAP_TICK));
pass++;
}
int main(int argc, char *argv[])
{
int fd;
int opt;
int interval = DEFAULT_INTERVAL;
int cycles_to_run = 0;
int i;
program = argv[0];
while((opt = getopt(argc, argv, "c:hi:t:v")) != -1) {
switch (opt) {
case 'h': usage(); exit(0); break;
case 'c': cycles_to_run = atoi(optarg); break;
case 'i': interval = atoi(optarg); break; /* number of seconds */
case 't': sync_tolerance = atoi(optarg); break; /* usec */
case 'v': verbose++; break;
default:
fprintf(stderr, "%s: Unknown option: %c. Aborting\n", argv[0], opt);
usage();
exit(1);
}
}
openlog(program, LOG_PERROR | LOG_PID, LOG_DAEMON);
fd = open("/dev/zap/pseudo", O_RDWR);
if (fd < 0) {
fprintf(stderr, "Unable to open zap interface: %s\n", strerror(errno));
exit(1);
}
if (verbose >=1)
syslog(LOG_INFO, "Opened pseudo zap interface, measuring accuracy...\n");
signal(SIGHUP, hup_handler);
signal(SIGINT, hup_handler);
signal(SIGUSR1, sigusr1_handler);
signal(SIGUSR2, sigusr2_handler);
if (cycles_to_run > 0) {
for(i=0; i<cycles_to_run; i++) {
sync_cycle(fd, interval);
}
hup_handler(0); /* exit */;
}
/* else (option -c not provided): run forever. */
for(;;) {
sync_cycle(fd, interval);
}
}
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