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