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/*
* timetrim.c
*
* "timetrim" allows setting and adjustment of the system clock frequency
* trim parameter on Silicon Graphics machines. The trim value native
* units are nanoseconds per second (10**-9), so a trim value of 1 makes
* the system clock step ahead 1 nanosecond more per second than a value
* of zero. Xntpd currently uses units of 2**-20 secs for its frequency
* offset (drift) values; to convert to a timetrim value, multiply by
* 1E9 / 2**20 (about 954).
*
* "timetrim" with no arguments just prints out the current kernel value.
* With a numeric argument, the kernel value is set to the supplied value.
* The "-i" flag causes the supplied value to be added to the kernel value.
* The "-n" option causes all input and output to be in xntpd units rather
* than timetrim native units.
*
* Note that there is a limit of +-3000000 (0.3%) on the timetrim value
* which is (silently?) enforced by the kernel.
*
*/
#include <stdio.h>
#include <ctype.h>
#include <sys/syssgi.h>
#define abs(X) (((X) < 0) ? -(X) : (X))
#define USAGE "usage: timetrim [-n] [[-i] value]\n"
#define SGITONTP(X) ((double)(X) * 1048576.0/1.0e9)
#define NTPTOSGI(X) ((LONG)((X) * 1.0e9/1048576.0))
main(argc, argv)
int argc;
char **argv;
{
char *rem;
int c, incremental = 0, ntpunits = 0;
LONG timetrim;
double value, strtod();
while (--argc && **++argv == '-' && isalpha(argv[0][1])) {
switch (argv[0][1]) {
case 'i':
incremental++;
break;
case 'n':
ntpunits++;
break;
default:
fprintf(stderr, USAGE);
exit(1);
}
}
if (syssgi(SGI_GETTIMETRIM, &timetrim) < 0) {
perror("syssgi");
exit(2);
}
if (argc == 0) {
if (ntpunits)
fprintf(stdout, "%0.5lf\n", SGITONTP(timetrim));
else
fprintf(stdout, "%ld\n", timetrim);
} else if (argc != 1) {
fprintf(stderr, USAGE);
exit(1);
} else {
value = strtod(argv[0], &rem);
if (*rem != '\0') {
fprintf(stderr, USAGE);
exit(1);
}
if (ntpunits)
value = NTPTOSGI(value);
if (incremental)
timetrim += value;
else
timetrim = value;
if (syssgi(SGI_SETTIMETRIM, timetrim) < 0) {
perror("syssgi");
exit(2);
}
}
}
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