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/* See LICENSE file for copyright and license details. */
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "util.h"
static void
usage(void)
{
eprintf("usage: %s [-u] [-d time] [+format | mmddHHMM[[CC]yy]]\n", argv0);
}
static int
datefield(const char *s, size_t i)
{
if (!isdigit(s[i]) || !isdigit(s[i+1]))
eprintf("invalid date format: %s\n", s);
return (s[i] - '0') * 10 + (s[i+1] - '0');
}
static void
setdate(const char *s, struct tm *now)
{
struct tm date;
struct timespec ts;
switch (strlen(s)) {
case 8:
date.tm_year = now->tm_year;
break;
case 10:
date.tm_year = datefield(s, 8);
if (date.tm_year < 69)
date.tm_year += 100;
break;
case 12:
date.tm_year = ((datefield(s, 8) - 19) * 100) + datefield(s, 10);
break;
default:
eprintf("invalid date format: %s\n", s);
break;
}
date.tm_mon = datefield(s, 0) - 1;
date.tm_mday = datefield(s, 2);
date.tm_hour = datefield(s, 4);
date.tm_min = datefield(s, 6);
date.tm_sec = 0;
date.tm_isdst = -1;
ts.tv_sec = mktime(&date);
if (ts.tv_sec == -1)
eprintf("mktime:");
ts.tv_nsec = 0;
if (clock_settime(CLOCK_REALTIME, &ts) == -1)
eprintf("clock_settime:");
}
int
main(int argc, char *argv[])
{
struct tm *now;
time_t t;
char buf[BUFSIZ], *fmt = "%a %b %e %H:%M:%S %Z %Y";
t = time(NULL);
if (t == -1)
eprintf("time:");
ARGBEGIN {
case 'd':
t = estrtonum(EARGF(usage()), 0, LLONG_MAX);
break;
case 'u':
if (setenv("TZ", "UTC0", 1) < 0)
eprintf("setenv:");
break;
default:
usage();
} ARGEND
if (!(now = localtime(&t)))
eprintf("localtime:");
if (argc) {
if (argc != 1)
usage();
if (argv[0][0] != '+') {
setdate(argv[0], now);
return 0;
}
fmt = &argv[0][1];
}
strftime(buf, sizeof(buf), fmt, now);
puts(buf);
return fshut(stdout, "<stdout>");
}