/* $Id $ */ /** @file * IPRT - Local Time, Posix. */ /* * Copyright (C) 2006-2023 Oracle and/or its affiliates. * * This file is part of VirtualBox base platform packages, as * available from https://www.virtualbox.org. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation, in version 3 of the * License. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . * * The contents of this file may alternatively be used under the terms * of the Common Development and Distribution License Version 1.0 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included * in the VirtualBox 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. * * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 */ /********************************************************************************************************************************* * Header Files * *********************************************************************************************************************************/ #define LOG_GROUP RTLOGGROUP_TIME #define RTTIME_INCL_TIMEVAL #include #include #include #include #include /** * 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; }