| // © 2016 and later: Unicode, Inc. and others. |
| // License & terms of use: http://www.unicode.org/copyright.html |
| /* |
| ******************************************************************************** |
| * Copyright (C) 2005-2015, International Business Machines |
| * Corporation and others. All Rights Reserved. |
| ******************************************************************************** |
| * |
| * File WINTZ.CPP |
| * |
| ******************************************************************************** |
| */ |
| |
| #include "unicode/utypes.h" |
| |
| #if U_PLATFORM_USES_ONLY_WIN32_API |
| |
| #include "wintz.h" |
| #include "charstr.h" |
| #include "cmemory.h" |
| #include "cstring.h" |
| |
| #include "unicode/ures.h" |
| #include "unicode/unistr.h" |
| #include "uresimp.h" |
| |
| #ifndef WIN32_LEAN_AND_MEAN |
| # define WIN32_LEAN_AND_MEAN |
| #endif |
| # define VC_EXTRALEAN |
| # define NOUSER |
| # define NOSERVICE |
| # define NOIME |
| # define NOMCX |
| #include <windows.h> |
| |
| U_NAMESPACE_BEGIN |
| |
| // Note these constants and the struct are only used when dealing with the fallback path for RDP sesssions. |
| |
| // This is the location of the time zones in the registry on Vista+ systems. |
| // See: https://docs.microsoft.com/windows/win32/api/timezoneapi/ns-timezoneapi-dynamic_time_zone_information |
| #define WINDOWS_TIMEZONES_REG_KEY_PATH L"SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Time Zones" |
| |
| // Max length for a registry key is 255. +1 for null. |
| // See: https://docs.microsoft.com/windows/win32/sysinfo/registry-element-size-limits |
| #define WINDOWS_MAX_REG_KEY_LENGTH 256 |
| |
| #if U_PLATFORM_HAS_WINUWP_API == 0 |
| |
| // This is the layout of the TZI binary value in the registry. |
| // See: https://docs.microsoft.com/windows/win32/api/timezoneapi/ns-timezoneapi-time_zone_information |
| typedef struct _REG_TZI_FORMAT { |
| LONG Bias; |
| LONG StandardBias; |
| LONG DaylightBias; |
| SYSTEMTIME StandardDate; |
| SYSTEMTIME DaylightDate; |
| } REG_TZI_FORMAT; |
| |
| #endif // U_PLATFORM_HAS_WINUWP_API |
| |
| /** |
| * This is main Windows time zone detection function. |
| * |
| * It returns the Windows time zone converted to an ICU time zone as a heap-allocated buffer, or nullptr upon failure. |
| * |
| * We use the Win32 API GetDynamicTimeZoneInformation (which is available since Vista) to get the current time zone info, |
| * as this API returns a non-localized time zone name which can be then mapped to an ICU time zone. |
| * |
| * However, in some RDP/terminal services situations, this struct isn't always fully complete, and the TimeZoneKeyName |
| * field of the struct might be NULL. This can happen with some 3rd party RDP clients, and also when using older versions |
| * of the RDP protocol, which don't send the newer TimeZoneKeyNamei information and only send the StandardName and DaylightName. |
| * |
| * Since these 3rd party clients and older RDP clients only send the pre-Vista time zone information to the server, this means that we |
| * need to fallback on using the pre-Vista methods to determine the time zone. This unfortunately requires examining the registry directly |
| * in order to try and determine the current time zone. |
| * |
| * Note that this can however still fail in some cases though if the client and server are using different languages, as the StandardName |
| * that is sent by client is localized in the client's language. However, we must compare this to the names that are on the server, which |
| * are localized in registry using the server's language. Despite that, this is the best we can do. |
| * |
| * Note: This fallback method won't work for the UWP version though, as we can't use the registry APIs in UWP. |
| * |
| * Once we have the current Windows time zone, then we can then map it to an ICU time zone ID (~ Olsen ID). |
| */ |
| U_CAPI const char* U_EXPORT2 |
| uprv_detectWindowsTimeZone() |
| { |
| // We first try to obtain the time zone directly by using the TimeZoneKeyName field of the DYNAMIC_TIME_ZONE_INFORMATION struct. |
| DYNAMIC_TIME_ZONE_INFORMATION dynamicTZI; |
| uprv_memset(&dynamicTZI, 0, sizeof(dynamicTZI)); |
| SYSTEMTIME systemTimeAllZero; |
| uprv_memset(&systemTimeAllZero, 0, sizeof(systemTimeAllZero)); |
| |
| if (GetDynamicTimeZoneInformation(&dynamicTZI) == TIME_ZONE_ID_INVALID) { |
| return nullptr; |
| } |
| |
| // If the DST setting has been turned off in the Control Panel, then return "Etc/GMT<offset>". |
| // |
| // Note: This logic is based on how the Control Panel itself determines if DST is 'off' on Windows. |
| // The code is somewhat convoluted; in a sort of pseudo-code it looks like this: |
| // |
| // IF (GetDynamicTimeZoneInformation != TIME_ZONE_ID_INVALID) && (DynamicDaylightTimeDisabled != 0) && |
| // (StandardDate == DaylightDate) && |
| // ( |
| // (TimeZoneKeyName != Empty && StandardDate == 0) || |
| // (TimeZoneKeyName == Empty && StandardDate != 0) |
| // ) |
| // THEN |
| // DST setting is "Disabled". |
| // |
| if (dynamicTZI.DynamicDaylightTimeDisabled != 0 && |
| uprv_memcmp(&dynamicTZI.StandardDate, &dynamicTZI.DaylightDate, sizeof(dynamicTZI.StandardDate)) == 0 && |
| ((dynamicTZI.TimeZoneKeyName[0] != L'\0' && uprv_memcmp(&dynamicTZI.StandardDate, &systemTimeAllZero, sizeof(systemTimeAllZero)) == 0) || |
| (dynamicTZI.TimeZoneKeyName[0] == L'\0' && uprv_memcmp(&dynamicTZI.StandardDate, &systemTimeAllZero, sizeof(systemTimeAllZero)) != 0))) |
| { |
| LONG utcOffsetMins = dynamicTZI.Bias; |
| if (utcOffsetMins == 0) { |
| return uprv_strdup("Etc/UTC"); |
| } |
| |
| // No way to support when DST is turned off and the offset in minutes is not a multiple of 60. |
| if (utcOffsetMins % 60 == 0) { |
| char gmtOffsetTz[11] = {}; // "Etc/GMT+dd" is 11-char long with a terminal null. |
| // Important note on the sign convention for zones: |
| // |
| // From https://en.wikipedia.org/wiki/Tz_database#Area |
| // "In order to conform with the POSIX style, those zone names beginning with "Etc/GMT" have their sign reversed |
| // from the standard ISO 8601 convention. In the "Etc" area, zones west of GMT have a positive sign and those |
| // east have a negative sign in their name (e.g "Etc/GMT-14" is 14 hours ahead of GMT)." |
| // |
| // Regarding the POSIX style, from https://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html |
| // "The offset specifies the time value you must add to the local time to get a Coordinated Universal Time value." |
| // |
| // However, the Bias value in DYNAMIC_TIME_ZONE_INFORMATION *already* follows the POSIX convention. |
| // |
| // From https://docs.microsoft.com/en-us/windows/win32/api/timezoneapi/ns-timezoneapi-dynamic_time_zone_information |
| // "The bias is the difference, in minutes, between Coordinated Universal Time (UTC) and |
| // local time. All translations between UTC and local time are based on the following formula: |
| // UTC = local time + bias" |
| // |
| // For example, a time zone that is 3 hours ahead of UTC (UTC+03:00) would have a Bias value of -180, and the |
| // corresponding time zone ID would be "Etc/GMT-3". (So there is no need to negate utcOffsetMins below.) |
| int ret = snprintf(gmtOffsetTz, UPRV_LENGTHOF(gmtOffsetTz), "Etc/GMT%+ld", utcOffsetMins / 60); |
| if (ret > 0 && ret < UPRV_LENGTHOF(gmtOffsetTz)) { |
| return uprv_strdup(gmtOffsetTz); |
| } |
| } |
| } |
| |
| // If DST is NOT disabled, but the TimeZoneKeyName field of the struct is NULL, then we may be dealing with a |
| // RDP/terminal services session where the 'Time Zone Redirection' feature is enabled. However, either the RDP |
| // client sent the server incomplete info (some 3rd party RDP clients only send the StandardName and DaylightName, |
| // but do not send the important TimeZoneKeyName), or if the RDP server has not appropriately populated the struct correctly. |
| // |
| // In this case we unfortunately have no choice but to fallback to using the pre-Vista method of determining the |
| // time zone, which requires examining the registry directly. |
| // |
| // Note that this can however still fail though if the client and server are using different languages, as the StandardName |
| // that is sent by client is *localized* in the client's language. However, we must compare this to the names that are |
| // on the server, which are *localized* in registry using the server's language. |
| // |
| // One other note is that this fallback method doesn't work for the UWP version, as we can't use the registry APIs. |
| |
| // windowsTimeZoneName will point at timezoneSubKeyName if we had to fallback to using the registry, and we found a match. |
| WCHAR timezoneSubKeyName[WINDOWS_MAX_REG_KEY_LENGTH]; |
| WCHAR *windowsTimeZoneName = dynamicTZI.TimeZoneKeyName; |
| |
| if (dynamicTZI.TimeZoneKeyName[0] == 0) { |
| |
| // We can't use the registry APIs in the UWP version. |
| #if U_PLATFORM_HAS_WINUWP_API == 1 |
| (void)timezoneSubKeyName; // suppress unused variable warnings. |
| return nullptr; |
| #else |
| // Open the path to the time zones in the Windows registry. |
| LONG ret; |
| HKEY hKeyAllTimeZones = nullptr; |
| ret = RegOpenKeyExW(HKEY_LOCAL_MACHINE, WINDOWS_TIMEZONES_REG_KEY_PATH, 0, KEY_READ, |
| reinterpret_cast<PHKEY>(&hKeyAllTimeZones)); |
| |
| if (ret != ERROR_SUCCESS) { |
| // If we can't open the key, then we can't do much, so fail. |
| return nullptr; |
| } |
| |
| // Read the number of subkeys under the time zone registry path. |
| DWORD numTimeZoneSubKeys; |
| ret = RegQueryInfoKeyW(hKeyAllTimeZones, nullptr, nullptr, nullptr, &numTimeZoneSubKeys, |
| nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr); |
| |
| if (ret != ERROR_SUCCESS) { |
| RegCloseKey(hKeyAllTimeZones); |
| return nullptr; |
| } |
| |
| // Examine each of the subkeys to try and find a match for the localized standard name ("Std"). |
| // |
| // Note: The name of the time zone subkey itself is not localized, but the "Std" name is localized. This means |
| // that we could fail to find a match if the RDP client and RDP server are using different languages, but unfortunately |
| // there isn't much we can do about it. |
| HKEY hKeyTimeZoneSubKey = nullptr; |
| ULONG registryValueType; |
| WCHAR registryStandardName[WINDOWS_MAX_REG_KEY_LENGTH]; |
| |
| for (DWORD i = 0; i < numTimeZoneSubKeys; i++) { |
| // Note: RegEnumKeyExW wants the size of the buffer in characters. |
| DWORD size = UPRV_LENGTHOF(timezoneSubKeyName); |
| ret = RegEnumKeyExW(hKeyAllTimeZones, i, timezoneSubKeyName, &size, nullptr, nullptr, nullptr, nullptr); |
| |
| if (ret != ERROR_SUCCESS) { |
| RegCloseKey(hKeyAllTimeZones); |
| return nullptr; |
| } |
| |
| ret = RegOpenKeyExW(hKeyAllTimeZones, timezoneSubKeyName, 0, KEY_READ, |
| reinterpret_cast<PHKEY>(&hKeyTimeZoneSubKey)); |
| |
| if (ret != ERROR_SUCCESS) { |
| RegCloseKey(hKeyAllTimeZones); |
| return nullptr; |
| } |
| |
| // Note: RegQueryValueExW wants the size of the buffer in bytes. |
| size = sizeof(registryStandardName); |
| ret = RegQueryValueExW(hKeyTimeZoneSubKey, L"Std", nullptr, ®istryValueType, |
| reinterpret_cast<LPBYTE>(registryStandardName), &size); |
| |
| if (ret != ERROR_SUCCESS || registryValueType != REG_SZ) { |
| RegCloseKey(hKeyTimeZoneSubKey); |
| RegCloseKey(hKeyAllTimeZones); |
| return nullptr; |
| } |
| |
| // Note: wcscmp does an ordinal (byte) comparison. |
| if (wcscmp(reinterpret_cast<WCHAR *>(registryStandardName), dynamicTZI.StandardName) == 0) { |
| // Since we are comparing the *localized* time zone name, it's possible that some languages might use |
| // the same string for more than one time zone. Thus we need to examine the TZI data in the registry to |
| // compare the GMT offset (the bias), and the DST transition dates, to ensure it's the same time zone |
| // as the currently reported one. |
| REG_TZI_FORMAT registryTziValue; |
| uprv_memset(®istryTziValue, 0, sizeof(registryTziValue)); |
| |
| // Note: RegQueryValueExW wants the size of the buffer in bytes. |
| DWORD timezoneTziValueSize = sizeof(registryTziValue); |
| ret = RegQueryValueExW(hKeyTimeZoneSubKey, L"TZI", nullptr, ®istryValueType, |
| reinterpret_cast<LPBYTE>(®istryTziValue), &timezoneTziValueSize); |
| |
| if (ret == ERROR_SUCCESS) { |
| if ((dynamicTZI.Bias == registryTziValue.Bias) && |
| (memcmp((const void *)&dynamicTZI.StandardDate, (const void *)®istryTziValue.StandardDate, sizeof(SYSTEMTIME)) == 0) && |
| (memcmp((const void *)&dynamicTZI.DaylightDate, (const void *)®istryTziValue.DaylightDate, sizeof(SYSTEMTIME)) == 0)) |
| { |
| // We found a matching time zone. |
| windowsTimeZoneName = timezoneSubKeyName; |
| break; |
| } |
| } |
| } |
| RegCloseKey(hKeyTimeZoneSubKey); |
| hKeyTimeZoneSubKey = nullptr; |
| } |
| |
| if (hKeyTimeZoneSubKey != nullptr) { |
| RegCloseKey(hKeyTimeZoneSubKey); |
| } |
| if (hKeyAllTimeZones != nullptr) { |
| RegCloseKey(hKeyAllTimeZones); |
| } |
| #endif // U_PLATFORM_HAS_WINUWP_API |
| } |
| |
| CharString winTZ; |
| UErrorCode status = U_ZERO_ERROR; |
| winTZ.appendInvariantChars(UnicodeString(TRUE, windowsTimeZoneName, -1), status); |
| |
| // Map Windows Timezone name (non-localized) to ICU timezone ID (~ Olson timezone id). |
| StackUResourceBundle winTZBundle; |
| ures_openDirectFillIn(winTZBundle.getAlias(), nullptr, "windowsZones", &status); |
| ures_getByKey(winTZBundle.getAlias(), "mapTimezones", winTZBundle.getAlias(), &status); |
| ures_getByKey(winTZBundle.getAlias(), winTZ.data(), winTZBundle.getAlias(), &status); |
| |
| if (U_FAILURE(status)) { |
| return nullptr; |
| } |
| |
| // Note: Since the ISO 3166 country/region codes are all invariant ASCII chars, we can |
| // directly downcast from wchar_t to do the conversion. |
| // We could call the A version of the GetGeoInfo API, but that would be slightly slower than calling the W API, |
| // as the A version of the API will end up calling MultiByteToWideChar anyways internally. |
| wchar_t regionCodeW[3] = {}; |
| char regionCode[3] = {}; // 2 letter ISO 3166 country/region code made entirely of invariant chars. |
| int geoId = GetUserGeoID(GEOCLASS_NATION); |
| int regionCodeLen = GetGeoInfoW(geoId, GEO_ISO2, regionCodeW, UPRV_LENGTHOF(regionCodeW), 0); |
| |
| const UChar *icuTZ16 = nullptr; |
| int32_t tzListLen = 0; |
| |
| if (regionCodeLen != 0) { |
| for (int i = 0; i < UPRV_LENGTHOF(regionCodeW); i++) { |
| regionCode[i] = static_cast<char>(regionCodeW[i]); |
| } |
| icuTZ16 = ures_getStringByKey(winTZBundle.getAlias(), regionCode, &tzListLen, &status); |
| } |
| if (regionCodeLen == 0 || U_FAILURE(status)) { |
| // fallback to default "001" (world) |
| status = U_ZERO_ERROR; |
| icuTZ16 = ures_getStringByKey(winTZBundle.getAlias(), "001", &tzListLen, &status); |
| } |
| |
| // Note: We want the first entry in the string returned by ures_getStringByKey. |
| // However this string can be a space delimited list of timezones: |
| // Ex: "America/New_York America/Detroit America/Indiana/Petersburg ..." |
| // We need to stop at the first space, so we pass tzLen (instead of tzListLen) to appendInvariantChars below. |
| int32_t tzLen = 0; |
| if (tzListLen > 0) { |
| while (!(icuTZ16[tzLen] == u'\0' || icuTZ16[tzLen] == u' ')) { |
| tzLen++; |
| } |
| } |
| |
| // Note: cloneData returns nullptr if the status is a failure, so this |
| // will return nullptr if the above look-up fails. |
| CharString icuTZStr; |
| return icuTZStr.appendInvariantChars(icuTZ16, tzLen, status).cloneData(status); |
| } |
| |
| U_NAMESPACE_END |
| #endif /* U_PLATFORM_USES_ONLY_WIN32_API */ |
