From 8f36514229bfaaa6ede8a2daa6aa920686d4251f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn-Egil=20Dahlberg?= <egil@erlang.org>
Date: Tue, 6 Dec 2011 02:55:13 +0100
Subject: Remove OS taint from datetime conversion

---
 erts/emulator/beam/bif.c          | 17 ++++-------------
 erts/emulator/beam/erl_time_sup.c | 28 +++++++++++++++++++++++++++-
 erts/emulator/beam/sys.h          |  8 ++++++--
 3 files changed, 37 insertions(+), 16 deletions(-)

(limited to 'erts')

diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index c3c247fffe..12dc7b3a48 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -3416,28 +3416,19 @@ BIF_RETTYPE seconds_to_universaltime_1(BIF_ALIST_1)
     Sint year, month, day;
     Sint hour, minute, second;
     Eterm res1, res2;
-    struct tm t;
     Eterm* hp;
 
-    time_t seconds = 0;
+    Sint64 time = 0;
 
-    if (is_not_integer(BIF_ARG_1)) {
+    if (!term_to_Sint64(BIF_ARG_1, &time)) {
 	BIF_ERROR(BIF_P, BADARG);
     }
 
-    seconds = (time_t)signed_val(BIF_ARG_1);
-
-    if (!gmtime_r(&seconds, &t)) {
+    if (!seconds_to_univ(time, &year, &month, &day,
+		&hour, &minute, &second)) {
 	BIF_ERROR(BIF_P, BADARG);
     }
 
-    year   = t.tm_year + 1900;
-    month  = t.tm_mon + 1;
-    day    = t.tm_hour;
-    minute = t.tm_min;
-    second = t.tm_sec;
-    /* isdst = t.tm_isdst */
-
     hp = HAlloc(BIF_P, 4+4+3);
     res1 = TUPLE3(hp,make_small(year),make_small(month),
 		  make_small(day));
diff --git a/erts/emulator/beam/erl_time_sup.c b/erts/emulator/beam/erl_time_sup.c
index 00a4906caa..edf03d06fb 100644
--- a/erts/emulator/beam/erl_time_sup.c
+++ b/erts/emulator/beam/erl_time_sup.c
@@ -651,8 +651,34 @@ static time_t gregday(Sint year, Sint month, Sint day)
 #define SECONDS_PER_MINUTE  (60)
 #define SECONDS_PER_HOUR    (60 * SECONDS_PER_MINUTE)
 #define SECONDS_PER_DAY     (24 * SECONDS_PER_HOUR)
-#define SECONDS_PER_YEAR    (86400)
 
+int seconds_to_univ(Sint64 time, Sint *year, Sint *month, Sint *day, 
+	Sint *hour, Sint *minute, Sint *second) {
+
+    Sint   y,mi;
+    Sint64 days = time / SECONDS_PER_DAY;
+    Sint   secs = time % SECONDS_PER_DAY;
+    Sint   tmp  = secs % SECONDS_PER_HOUR;
+
+    *hour   = secs / SECONDS_PER_HOUR;
+    *minute = tmp  / SECONDS_PER_MINUTE;
+    *second = tmp  % SECONDS_PER_MINUTE;
+
+    days   += 719468;
+    y       = (10000*days + 14780) / 3652425; /* seriosly? */
+    tmp     = days - (365 * y + y/4 - y/100 + y/400);
+
+    if (tmp < 0) {
+	y--;
+	tmp = days - (365*y + y/4 - y/100 + y/400);
+    }
+    mi = (100 * tmp + 52)/3060;
+    *month = (mi + 2) % 12 + 1;
+    *year  = y + (mi + 2) / 12;
+    *day   = tmp - (mi * 306 + 5)/10 + 1;
+
+    return 1;
+}
 
 int univ_to_seconds(Sint year, Sint month, Sint day, Sint hour, Sint minute, Sint second, Sint64 *time) {
     Sint days;
diff --git a/erts/emulator/beam/sys.h b/erts/emulator/beam/sys.h
index 3abae2243c..038c319470 100644
--- a/erts/emulator/beam/sys.h
+++ b/erts/emulator/beam/sys.h
@@ -666,11 +666,15 @@ void get_localtime(int *year, int *month, int *day,
 		   int *hour, int *minute, int *second);
 void get_universaltime(int *year, int *month, int *day, 
 		       int *hour, int *minute, int *second);
-int univ_to_local(Sint *year, Sint *month, Sint *day, 
-		  Sint *hour, Sint *minute, Sint *second);
+int seconds_to_univ(Sint64 seconds, 
+		    Sint *year, Sint *month, Sint *day, 
+		    Sint *hour, Sint *minute, Sint *second);
 int univ_to_seconds(Sint year, Sint month, Sint day, 
 		    Sint hour, Sint minute, Sint second,
 		    Sint64* seconds);
+int univ_to_local(
+    Sint *year, Sint *month, Sint *day, 
+		  Sint *hour, Sint *minute, Sint *second);
 int local_to_univ(Sint *year, Sint *month, Sint *day, 
 		  Sint *hour, Sint *minute, Sint *second, int isdst);
 void get_now(Uint*, Uint*, Uint*);
-- 
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