1 files changed, 103 insertions, 0 deletions
diff --git a/util/sbase/date.c b/util/sbase/date.c
new file mode 100644
index 00000000..109f3710
--- /dev/null
+++ b/util/sbase/date.c
@@ -0,0 +1,103 @@
+/* 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>");
+}