first try at implementing getdate function

src/time/getdate.c

@@ -0,0 +1,47 @@
+#include <time.h>
+#include <pthread.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int getdate_err;
+
+struct tm *getdate(const char *s)
+{
+	static struct tm tmbuf;
+	struct tm *ret = 0;
+	char *datemsk = getenv("DATEMSK");
+	FILE *f = 0;
+	char fmt[100], *p;
+	int cs;
+
+	pthread_setcancelstate(PTHREAD_CANCEL_DEFERRED, &cs);
+
+	if (!datemsk) {
+		getdate_err = 1;
+		goto out;
+	}
+
+	f = fopen(datemsk, "r");
+	if (!f) {
+		if (errno == ENOMEM) getdate_err = 6;
+		else getdate_err = 2;
+		goto out;
+	}
+
+	while (fgets(fmt, sizeof fmt, f)) {
+		p = strptime(s, fmt, &tmbuf);
+dprintf(2, "%s %s\n", s, fmt);
+dprintf(2, "%p %d\n", p, p?*p:0);
+		if (p && !*p) {
+			ret = &tmbuf;
+			goto out;
+		}
+	}
+
+	getdate_err = 7;
+out:
+	if (f) fclose(f);
+	pthread_setcancelstate(cs, 0);
+	return ret;
+}