/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#include <windows.h>

#include <stdio.h>

#include <stdlib.h>

#include "jvm.h"

#include "TimeZone_md.h"

#define VALUE_UNKNOWN           0

#define VALUE_KEY               1

#define VALUE_MAPID             2

#define VALUE_GMTOFFSET         3

#define MAX_ZONE_CHAR           256

#define MAX_MAPID_LENGTH        32

#define NT_TZ_KEY               "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Time Zones"

#define WIN_TZ_KEY              "SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Time Zones"

#define WIN_CURRENT_TZ_KEY      "System\\CurrentControlSet\\Control\\TimeZoneInformation"

typedef struct _TziValue {

    LONG        bias;

    LONG        stdBias;

    LONG        dstBias;

    SYSTEMTIME  stdDate;

    SYSTEMTIME  dstDate;

} TziValue;

/*

 * Registry key names

 */

static void *keyNames[] = {

    (void *) L"StandardName",

    (void *) "StandardName",

    (void *) L"Std",

    (void *) "Std"

};

/*

 * Indices to keyNames[]

 */

#define STANDARD_NAME           0

#define STD_NAME                2

/*

 * Calls RegQueryValueEx() to get the value for the specified key. If

 * the platform is NT, 2000 or XP, it calls the Unicode

 * version. Otherwise, it calls the ANSI version and converts the

 * value to Unicode. In this case, it assumes that the current ANSI

 * Code Page is the same as the native platform code page (e.g., Code

 * Page 932 for the Japanese Windows systems.

 *

 * `keyIndex' is an index value to the keyNames in Unicode

 * (WCHAR). `keyIndex' + 1 points to its ANSI value.

 *

 * Returns the status value. ERROR_SUCCESS if succeeded, a

 * non-ERROR_SUCCESS value otherwise.

 */

static LONG

getValueInRegistry(HKEY hKey,

                   int keyIndex,

                   LPDWORD typePtr,

                   LPBYTE buf,

                   LPDWORD bufLengthPtr)

{

    LONG ret;

    DWORD bufLength = *bufLengthPtr;

    char val[MAX_ZONE_CHAR];

    DWORD valSize;

    int len;

    *typePtr = 0;

    ret = RegQueryValueExW(hKey, (WCHAR *) keyNames[keyIndex], NULL,

                           typePtr, buf, bufLengthPtr);

    if (ret == ERROR_SUCCESS && *typePtr == REG_SZ) {

        return ret;

    }

    valSize = sizeof(val);

    ret = RegQueryValueExA(hKey, (char *) keyNames[keyIndex + 1], NULL,

                           typePtr, val, &valSize);

    if (ret != ERROR_SUCCESS) {

        return ret;

    }

    if (*typePtr != REG_SZ) {

        return ERROR_BADKEY;

    }

    len = MultiByteToWideChar(CP_ACP, MB_ERR_INVALID_CHARS,

                              (LPCSTR) val, -1,

                              (LPWSTR) buf, bufLength/sizeof(WCHAR));

    if (len <= 0) {

        return ERROR_BADKEY;

    }

    return ERROR_SUCCESS;

}

/*

 * Produces custom name "GMT+hh:mm" from the given bias in buffer.

 */

static void customZoneName(LONG bias, char *buffer) {

    LONG gmtOffset;

    int sign;

    if (bias > 0) {

        gmtOffset = bias;

        sign = -1;

    } else {

        gmtOffset = -bias;

        sign = 1;

    }

    if (gmtOffset != 0) {

        sprintf(buffer, "GMT%c%02d:%02d",

                ((sign >= 0) ? '+' : '-'),

                gmtOffset / 60,

                gmtOffset % 60);

    } else {

        strcpy(buffer, "GMT");

    }

}

/*

 * Gets the current time zone entry in the "Time Zones" registry.

 */

static int getWinTimeZone(char *winZoneName, char *winMapID)

{

    TIME_ZONE_INFORMATION tzi;

    OSVERSIONINFO ver;

    int onlyMapID;

    HANDLE hKey = NULL, hSubKey = NULL;

    LONG ret;

    DWORD nSubKeys, i;

    ULONG valueType;

    TCHAR subKeyName[MAX_ZONE_CHAR];

    TCHAR szValue[MAX_ZONE_CHAR];

    WCHAR stdNameInReg[MAX_ZONE_CHAR];

    TziValue tempTzi;

    WCHAR *stdNamePtr = tzi.StandardName;

    DWORD valueSize;

    DWORD timeType;

    int isVista;

    /*

     * Get the current time zone setting of the platform.

     */

    timeType = GetTimeZoneInformation(&tzi);

    if (timeType == TIME_ZONE_ID_INVALID) {

        goto err;

    }

    /*

     * Determine if this is an NT system.

     */

    ver.dwOSVersionInfoSize = sizeof(ver);

    GetVersionEx(&ver);

    isVista = ver.dwMajorVersion >= 6;

    ret = RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_CURRENT_TZ_KEY, 0,

                       KEY_READ, (PHKEY)&hKey);

    if (ret == ERROR_SUCCESS) {

        DWORD val;

        DWORD bufSize;

        /*

         * Determine if auto-daylight time adjustment is turned off.

         */

        valueType = 0;

        bufSize = sizeof(val);

        ret = RegQueryValueExA(hKey, "DisableAutoDaylightTimeSet",

                               NULL, &valueType, (LPBYTE) &val, &bufSize);

        /*

         * Vista uses the different key name.

         */

        if (ret != ERROR_SUCCESS) {

            ret = RegQueryValueExA(hKey, "DynamicDaylightTimeDisabled",

                                   NULL, &valueType, (LPBYTE) &val, &bufSize);

        }

        if (ret == ERROR_SUCCESS) {

            int daylightSavingsUpdateDisabledOther = val == 1 && tzi.DaylightDate.wMonth != 0;

            int daylightSavingsUpdateDisabledVista = val == 1;

            int daylightSavingsUpdateDisabled = isVista ? daylightSavingsUpdateDisabledVista : daylightSavingsUpdateDisabledOther;

            if (daylightSavingsUpdateDisabled) {

                (void) RegCloseKey(hKey);

                customZoneName(tzi.Bias, winZoneName);

                return VALUE_GMTOFFSET;

            }

        }

        /*

         * Vista has the key for the current "Time Zones" entry.

         */

        if (isVista) {

            valueType = 0;

            bufSize = MAX_ZONE_CHAR;

            ret = RegQueryValueExA(hKey, "TimeZoneKeyName", NULL,

                                   &valueType, (LPBYTE) winZoneName, &bufSize);

            if (ret != ERROR_SUCCESS) {

                goto err;

            }

            (void) RegCloseKey(hKey);

            return VALUE_KEY;

        }

        /*

         * Win32 problem: If the length of the standard time name is equal

         * to (or probably longer than) 32 in the registry,

         * GetTimeZoneInformation() on NT returns a null string as its

         * standard time name. We need to work around this problem by

         * getting the same information from the TimeZoneInformation

         * registry. The function on Win98 seems to return its key name.

         * We can't do anything in that case.

         */

        if (tzi.StandardName[0] == 0) {

            bufSize = sizeof(stdNameInReg);

            ret = getValueInRegistry(hKey, STANDARD_NAME, &valueType,

                                     (LPBYTE) stdNameInReg, &bufSize);

            if (ret != ERROR_SUCCESS) {

                goto err;

            }

            stdNamePtr = stdNameInReg;

        }

        (void) RegCloseKey(hKey);

    }

    /*

     * Open the "Time Zones" registry.

     */

    ret = RegOpenKeyEx(HKEY_LOCAL_MACHINE, NT_TZ_KEY, 0, KEY_READ, (PHKEY)&hKey);

    if (ret != ERROR_SUCCESS) {

        ret = RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_TZ_KEY, 0, KEY_READ, (PHKEY)&hKey);

        /*

         * If both failed, then give up.

         */

        if (ret != ERROR_SUCCESS) {

            return VALUE_UNKNOWN;

        }

    }

    /*

     * Get the number of subkeys of the "Time Zones" registry for

     * enumeration.

     */

    ret = RegQueryInfoKey(hKey, NULL, NULL, NULL, &nSubKeys,

                          NULL, NULL, NULL, NULL, NULL, NULL, NULL);

    if (ret != ERROR_SUCCESS) {

        goto err;

    }

    /*

     * Compare to the "Std" value of each subkey and find the entry that

     * matches the current control panel setting.

     */

    onlyMapID = 0;

    for (i = 0; i < nSubKeys; ++i) {

        DWORD size = sizeof(subKeyName);

        ret = RegEnumKeyEx(hKey, i, subKeyName, &size, NULL, NULL, NULL, NULL);

        if (ret != ERROR_SUCCESS) {

            goto err;

        }

        ret = RegOpenKeyEx(hKey, subKeyName, 0, KEY_READ, (PHKEY)&hSubKey);

        if (ret != ERROR_SUCCESS) {

            goto err;

        }

        size = sizeof(szValue);

        ret = getValueInRegistry(hSubKey, STD_NAME, &valueType,

                                 szValue, &size);

        if (ret != ERROR_SUCCESS) {

            /*

             * NT 4.0 SP3 fails here since it doesn't have the "Std"

             * entry in the Time Zones registry.

             */

            RegCloseKey(hSubKey);

            onlyMapID = 1;

            ret = RegOpenKeyExW(hKey, stdNamePtr, 0, KEY_READ, (PHKEY)&hSubKey);

            if (ret != ERROR_SUCCESS) {

                goto err;

            }

            break;

        }

        if (wcscmp((WCHAR *)szValue, stdNamePtr) == 0) {

            /*

             * Some localized Win32 platforms use a same name to

             * different time zones. So, we can't rely only on the name

             * here. We need to check GMT offsets and transition dates

             * to make sure it's the registry of the current time

             * zone.

             */

            DWORD tziValueSize = sizeof(tempTzi);

            ret = RegQueryValueEx(hSubKey, "TZI", NULL, &valueType,

                                  (unsigned char *) &tempTzi, &tziValueSize);

            if (ret == ERROR_SUCCESS) {

                if ((tzi.Bias != tempTzi.bias) ||

                    (memcmp((const void *) &tzi.StandardDate,

                            (const void *) &tempTzi.stdDate,

                            sizeof(SYSTEMTIME)) != 0)) {

                        goto out;

                }

                if (tzi.DaylightBias != 0) {

                    if ((tzi.DaylightBias != tempTzi.dstBias) ||

                        (memcmp((const void *) &tzi.DaylightDate,

                                (const void *) &tempTzi.dstDate,

                                sizeof(SYSTEMTIME)) != 0)) {

                        goto out;

                    }

                }

            }

            /*

             * found matched record, terminate search

             */

            strcpy(winZoneName, subKeyName);

            break;

        }

    out:

        (void) RegCloseKey(hSubKey);

    }

    /*

     * Get the "MapID" value of the registry to be able to eliminate

     * duplicated key names later.

     */

    valueSize = MAX_MAPID_LENGTH;

    ret = RegQueryValueExA(hSubKey, "MapID", NULL, &valueType, winMapID, &valueSize);

    (void) RegCloseKey(hSubKey);

    (void) RegCloseKey(hKey);

    if (ret != ERROR_SUCCESS) {

        /*

         * Vista doesn't have mapID. VALUE_UNKNOWN should be returned

         * only for Windows NT.

         */

        if (onlyMapID == 1) {

            return VALUE_UNKNOWN;

        }

    }

    return VALUE_KEY;

 err:

    if (hKey != NULL) {

        (void) RegCloseKey(hKey);

    }

    return VALUE_UNKNOWN;

}

/*

 * The mapping table file name.

 */

#define MAPPINGS_FILE "\\lib\\tzmappings"

/*

 * Index values for the mapping table.

 */

#define TZ_WIN_NAME     0

#define TZ_MAPID        1

#define TZ_REGION       2

#define TZ_JAVA_NAME    3

#define TZ_NITEMS       4       /* number of items (fields) */

/*

 * Looks up the mapping table (tzmappings) and returns a Java time

 * zone ID (e.g., "America/Los_Angeles") if found. Otherwise, NULL is

 * returned.

 *

 * value_type is one of the following values:

 *      VALUE_KEY for exact key matching

 *      VALUE_MAPID for MapID (this is

 *      required for the old Windows, such as NT 4.0 SP3).

 */

static char *matchJavaTZ(const char *java_home_dir, int value_type, char *tzName,

                         char *mapID)

{

    int line;

    int IDmatched = 0;

    FILE *fp;

    char *javaTZName = NULL;

    char *items[TZ_NITEMS];

    char *mapFileName;

    char lineBuffer[MAX_ZONE_CHAR * 4];

    int noMapID = *mapID == '\0';       /* no mapID on Vista and later */

    mapFileName = malloc(strlen(java_home_dir) + strlen(MAPPINGS_FILE) + 1);

    if (mapFileName == NULL) {

        return NULL;

    }

    strcpy(mapFileName, java_home_dir);

    strcat(mapFileName, MAPPINGS_FILE);

    if ((fp = fopen(mapFileName, "r")) == NULL) {

        jio_fprintf(stderr, "can't open %s.\n", mapFileName);

        free((void *) mapFileName);

        return NULL;

    }

    free((void *) mapFileName);

    line = 0;

    while (fgets(lineBuffer, sizeof(lineBuffer), fp) != NULL) {

        char *start, *idx, *endp;

        int itemIndex = 0;

        line++;

        start = idx = lineBuffer;

        endp = &lineBuffer[sizeof(lineBuffer)];

        /*

         * Ignore comment and blank lines.

         */

        if (*idx == '#' || *idx == '\n') {

            continue;

        }

        for (itemIndex = 0; itemIndex < TZ_NITEMS; itemIndex++) {

            items[itemIndex] = start;

            while (*idx && *idx != ':') {

                if (++idx >= endp) {

                    goto illegal_format;

                }

            }

            if (*idx == '\0') {

                goto illegal_format;

            }

            *idx++ = '\0';

            start = idx;

        }

        if (*idx != '\n') {

            goto illegal_format;

        }

        if (noMapID || strcmp(mapID, items[TZ_MAPID]) == 0) {

            /*

             * When there's no mapID, we need to scan items until the

             * exact match is found or the end of data is detected.

             */

            if (!noMapID) {

                IDmatched = 1;

            }

            if (strcmp(items[TZ_WIN_NAME], tzName) == 0) {

                /*

                 * Found the time zone in the mapping table.

                 */

                javaTZName = _strdup(items[TZ_JAVA_NAME]);

                break;

            }

        } else {

            if (IDmatched == 1) {

                /*

                 * No need to look up the mapping table further.

                 */

                break;

            }

        }

    }

    fclose(fp);

    return javaTZName;

 illegal_format:

    (void) fclose(fp);

    jio_fprintf(stderr, "tzmappings: Illegal format at line %d.\n", line);

    return NULL;

}

/*

 * Detects the platform time zone which maps to a Java time zone ID.

 */

char *findJavaTZ_md(const char *java_home_dir)

{

    char winZoneName[MAX_ZONE_CHAR];

    char winMapID[MAX_MAPID_LENGTH];

    char *std_timezone = NULL;

    int  result;

    winMapID[0] = 0;

    result = getWinTimeZone(winZoneName, winMapID);

    if (result != VALUE_UNKNOWN) {

        if (result == VALUE_GMTOFFSET) {

            std_timezone = _strdup(winZoneName);

        } else {

            std_timezone = matchJavaTZ(java_home_dir, result,

                                       winZoneName, winMapID);

        }

    }

    return std_timezone;

}

/**

 */