From: Ralph Boehme <slow@samba.org>
Date: Thu, 5 Dec 2019 14:00:19 +0000 (+0100)
Subject: lib: add nt_time_to_full_timespec()
X-Git-Tag: ldb-2.1.0~428
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=af142df467fd434d5d45d55a3fd4c017bf673c7e;p=thirdparty%2Fsamba.git

lib: add nt_time_to_full_timespec()

BUG: https://bugzilla.samba.org/show_bug.cgi?id=7771

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
---

diff --git a/lib/util/time.c b/lib/util/time.c
index 67308444dae..8e68662dfa3 100644
--- a/lib/util/time.c
+++ b/lib/util/time.c
@@ -1039,3 +1039,44 @@ NTTIME full_timespec_to_nt_time(const struct timespec *ts)
 
 	return d;
 }
+
+/**
+ * Like nt_time_to_unix_timespec() but allowing negative tv_sec values and
+ * returning NTTIME=0 and -1 as struct timespec {.tv_nsec = SAMBA_UTIME_OMIT}.
+ *
+ * See also: is_omit_timespec().
+ **/
+struct timespec nt_time_to_full_timespec(NTTIME nt)
+{
+	int64_t d;
+	struct timespec ret;
+
+	if ((nt == 0) || (nt == (int64_t)-1)) {
+		return (struct timespec){.tv_nsec = SAMBA_UTIME_OMIT};
+	}
+
+	d = (int64_t)nt;
+	/* d is now in 100ns units, since jan 1st 1601".
+	   Save off the ns fraction. */
+
+	/*
+	 * Take the last seven decimal digits and multiply by 100.
+	 * to convert from 100ns units to 1ns units.
+	 */
+        ret.tv_nsec = (long) ((d % (1000 * 1000 * 10)) * 100);
+
+	/* Convert to seconds */
+	d /= 1000*1000*10;
+
+	/* Now adjust by 369 years to make the secs since 1970 */
+	d -= TIME_FIXUP_CONSTANT_INT;
+
+	if (d >= (int64_t)TIME_T_MAX) {
+		ret.tv_sec = TIME_T_MAX;
+		ret.tv_nsec = 0;
+		return ret;
+	}
+
+	ret.tv_sec = (time_t)d;
+	return ret;
+}
diff --git a/lib/util/time.h b/lib/util/time.h
index 5c7b7b209ec..29c8001485f 100644
--- a/lib/util/time.h
+++ b/lib/util/time.h
@@ -342,5 +342,6 @@ NTTIME unix_timespec_to_nt_time(struct timespec ts);
 bool is_omit_timespec(const struct timespec *ts);
 struct timespec make_omit_timespec(void);
 NTTIME full_timespec_to_nt_time(const struct timespec *ts);
+struct timespec nt_time_to_full_timespec(NTTIME nt);
 
 #endif /* _SAMBA_TIME_H_ */