1 files changed, 205 insertions, 0 deletions
diff --git a/src/VBox/Runtime/r3/posix/timelocal-posix.cpp b/src/VBox/Runtime/r3/posix/timelocal-posix.cpp
new file mode 100644
index 00000000..a7b275eb
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/timelocal-posix.cpp
@@ -0,0 +1,205 @@
+/* $Id $ */
+/** @file
+ * IPRT - Local Time, Posix.
+ */
+
+/*
+ * Copyright (C) 2006-2020 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+ * VirtualBox OSE distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIME
+#define RTTIME_INCL_TIMEVAL
+#include <iprt/types.h>
+#include <iprt/assert.h>
+
+#include <sys/time.h>
+#include <time.h>
+
+#include <iprt/time.h>
+
+
+/**
+ * This tries to find the UTC offset for a given timespec.
+ *
+ * It does probably not take into account changes in daylight
+ * saving over the years or similar stuff.
+ *
+ * @returns UTC offset in nanoseconds.
+ * @param   pTime           The time.
+ * @param   fCurrentTime    Whether the input is current time or not.
+ *                          This is for avoid infinit recursion on errors in the fallback path.
+ */
+static int64_t rtTimeLocalUTCOffset(PCRTTIMESPEC pTime, bool fCurrentTime)
+{
+    RTTIMESPEC Fallback;
+
+    /*
+     * Convert to time_t.
+     */
+    int64_t i64UnixTime = RTTimeSpecGetSeconds(pTime);
+    time_t UnixTime = i64UnixTime;
+    if (UnixTime != i64UnixTime)
+        return fCurrentTime ? 0 : rtTimeLocalUTCOffset(RTTimeNow(&Fallback), true);
+
+    /*
+     * Explode it as both local and UTC time.
+     */
+    struct tm TmLocal;
+    if (    !localtime_r(&UnixTime, &TmLocal)
+        ||  !TmLocal.tm_year)
+        return fCurrentTime ? 0 : rtTimeLocalUTCOffset(RTTimeNow(&Fallback), true);
+    struct tm TmUtc;
+    if (!gmtime_r(&UnixTime, &TmUtc))
+        return fCurrentTime ? 0 : rtTimeLocalUTCOffset(RTTimeNow(&Fallback), true);
+
+    /*
+     * Calc the difference (if any).
+     * We ASSUME that the difference is less that 24 hours.
+     */
+    if (    TmLocal.tm_hour == TmUtc.tm_hour
+        &&  TmLocal.tm_min  == TmUtc.tm_min
+        &&  TmLocal.tm_sec  == TmUtc.tm_sec
+        &&  TmLocal.tm_mday == TmUtc.tm_mday)
+        return 0;
+
+    int cLocalSecs = TmLocal.tm_hour * 3600
+                   + TmLocal.tm_min * 60
+                   + TmLocal.tm_sec;
+    int cUtcSecs   = TmUtc.tm_hour * 3600
+                   + TmUtc.tm_min * 60
+                   + TmUtc.tm_sec;
+    if (TmLocal.tm_mday != TmUtc.tm_mday)
+    {
+        /*
+         * Must add 24 hours to the value that is ahead of the other.
+         *
+         * To determine which is ahead was busted for a long long time (bugref:9078),
+         * so here are some examples and two different approaches.
+         *
+         *  TmLocal              TmUtc              => Add 24:00 to     => Diff
+         *  2007-04-02 01:00     2007-04-01 23:00   => TmLocal          => +02:00
+         *  2007-04-01 01:00     2007-03-31 23:00   => TmLocal          => +02:00
+         *  2007-03-31 01:00     2007-03-30 23:00   => TmLocal          => +02:00
+         *
+         *  2007-04-01 01:00     2007-04-02 23:00   => TmUtc            => -02:00
+         *  2007-03-31 23:00     2007-04-01 01:00   => TmUtc            => -02:00
+         *  2007-03-30 23:00     2007-03-31 01:00   => TmUtc            => -02:00
+         *
+         */
+#if 0
+        /* Using day of month turned out to be a little complicated. */
+        if (   (   TmLocal.tm_mday > TmUtc.tm_mday
+                && (TmUtc.tm_mday != 1 || TmLocal.tm_mday < 28) )
+            || (TmLocal.tm_mday == 1 && TmUtc.tm_mday >= 28) )
+        {
+            cLocalSecs += 24*60*60;
+            Assert(   TmLocal.tm_yday - TmUtc.tm_yday == 1
+                   || (TmLocal.tm_yday == 0 && TmUtc.tm_yday >= 364 && TmLocal.tm_year == TmUtc.tm_year + 1));
+        }
+        else
+        {
+            cUtcSecs   += 24*60*60;
+            Assert(   TmUtc.tm_yday - TmLocal.tm_yday == 1
+                   || (TmUtc.tm_yday == 0 && TmLocal.tm_yday >= 364 && TmUtc.tm_year == TmLocal.tm_year + 1));
+        }
+#else
+        /* Using day of year and year is simpler. */
+        if (   (   TmLocal.tm_year == TmUtc.tm_year
+                && TmLocal.tm_yday > TmUtc.tm_yday)
+            || TmLocal.tm_year > TmUtc.tm_year)
+        {
+            cLocalSecs += 24*60*60;
+            Assert(   TmLocal.tm_yday - TmUtc.tm_yday == 1
+                   || (TmLocal.tm_yday == 0 && TmUtc.tm_yday >= 364 && TmLocal.tm_year == TmUtc.tm_year + 1));
+        }
+        else
+        {
+            cUtcSecs   += 24*60*60;
+            Assert(   TmUtc.tm_yday - TmLocal.tm_yday == 1
+                   || (TmUtc.tm_yday == 0 && TmLocal.tm_yday >= 364 && TmUtc.tm_year == TmLocal.tm_year + 1));
+        }
+#endif
+    }
+
+    return (cLocalSecs - cUtcSecs) * INT64_C(1000000000);
+}
+
+
+/**
+ * Gets the current delta between UTC and local time.
+ *
+ * @code
+ *      RTTIMESPEC LocalTime;
+ *      RTTimeSpecAddNano(RTTimeNow(&LocalTime), RTTimeLocalDeltaNano());
+ * @endcode
+ *
+ * @returns Returns the nanosecond delta between UTC and local time.
+ */
+RTDECL(int64_t) RTTimeLocalDeltaNano(void)
+{
+    RTTIMESPEC Time;
+    return rtTimeLocalUTCOffset(RTTimeNow(&Time), true /* current time, skip fallback */);
+}
+
+
+/**
+ * Gets the delta between UTC and local time at the given time.
+ *
+ * @code
+ *      RTTIMESPEC LocalTime;
+ *      RTTimeNow(&LocalTime);
+ *      RTTimeSpecAddNano(&LocalTime, RTTimeLocalDeltaNanoFor(&LocalTime));
+ * @endcode
+ *
+ * @param   pTimeSpec   The time spec giving the time to get the delta for.
+ * @returns Returns the nanosecond delta between UTC and local time.
+ */
+RTDECL(int64_t) RTTimeLocalDeltaNanoFor(PCRTTIMESPEC pTimeSpec)
+{
+    AssertPtr(pTimeSpec);
+    return rtTimeLocalUTCOffset(pTimeSpec, false /* current time, skip fallback */);
+}
+
+
+/**
+ * Explodes a time spec to the localized timezone.
+ *
+ * @returns pTime.
+ * @param   pTime       Where to store the exploded time.
+ * @param   pTimeSpec   The time spec to exploded. (UTC)
+ */
+RTDECL(PRTTIME) RTTimeLocalExplode(PRTTIME pTime, PCRTTIMESPEC pTimeSpec)
+{
+    RTTIMESPEC LocalTime = *pTimeSpec;
+    int64_t cNsUtcOffset = rtTimeLocalUTCOffset(&LocalTime, true /* current time, skip fallback */);
+    RTTimeSpecAddNano(&LocalTime, cNsUtcOffset);
+    pTime = RTTimeExplode(pTime, &LocalTime);
+    if (pTime)
+    {
+        pTime->fFlags = (pTime->fFlags & ~RTTIME_FLAGS_TYPE_MASK) | RTTIME_FLAGS_TYPE_LOCAL;
+        pTime->offUTC = cNsUtcOffset / RT_NS_1MIN;
+    }
+    return pTime;
+}
+