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+/* java.util.VMTimeZone
+ Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2007
+ Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath 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; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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 GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package java.util;
+
+import gnu.classpath.Configuration;
+import gnu.classpath.SystemProperties;
+import gnu.java.util.ZoneInfo;
+import java.util.TimeZone;
+
+import java.io.*;
+
+/**
+ *
+ */
+final class VMTimeZone
+{
+ static
+ {
+ if (Configuration.INIT_LOAD_LIBRARY)
+ {
+ System.loadLibrary("javautil");
+ }
+ }
+
+ /**
+ * This method returns a time zone id string which is in the form
+ * (standard zone name) or (standard zone name)(GMT offset) or
+ * (standard zone name)(GMT offset)(daylight time zone name). The
+ * GMT offset can be in seconds, or where it is evenly divisible by
+ * 3600, then it can be in hours. The offset must be the time to
+ * add to the local time to get GMT. If a offset is given and the
+ * time zone observes daylight saving then the (daylight time zone
+ * name) must also be given (otherwise it is assumed the time zone
+ * does not observe any daylight savings).
+ * <p>
+ * The result of this method is given to the method
+ * TimeZone.getDefaultTimeZone(String) which tries to map the time
+ * zone id to a known TimeZone. See that method on how the returned
+ * String is mapped to a real TimeZone object.
+ * <p>
+ * The reference implementation which is made for GNU/Posix like
+ * systems calls <code>System.getenv("TZ")</code>,
+ * <code>readTimeZoneFile("/etc/timezone")</code>,
+ * <code>ZoneInfo.readTZFile((String)null, "/etc/localtime")</code>
+ * and finally <code>getSystemTimeZoneId()</code> till a supported
+ * TimeZone is found through
+ * <code>TimeZone.getDefaultTimeZone(String)</code>.
+ * If every method fails <code>null</code> is returned (which means
+ * the TimeZone code will fall back on GMT as default time zone).
+ * <p>
+ * Note that this method is called inside a
+ * <code>AccessController.doPrivileged()</code> block and runs with
+ * the priviliges of the java.util system classes. It will only be
+ * called when the default time zone is not yet set, the system
+ * property user.timezone isn't set and it is requested for the
+ * first time.
+ */
+ static TimeZone getDefaultTimeZoneId()
+ {
+ TimeZone zone = null;
+
+ // See if TZ environment variable is set and accessible.
+ String tzid = System.getenv("TZ");
+ if (tzid != null && !tzid.equals(""))
+ zone = TimeZone.getDefaultTimeZone(tzid);
+
+ // Try to parse /etc/timezone.
+ if (zone == null)
+ {
+ tzid = readTimeZoneFile("/etc/timezone");
+ if (tzid != null && !tzid.equals(""))
+ zone = TimeZone.getDefaultTimeZone(tzid);
+ }
+
+ // Try to parse /etc/localtime
+ if (zone == null)
+ {
+ zone = ZoneInfo.readTZFile((String) null, "/etc/localtime");
+ if (zone != null)
+ {
+ // Try to find a more suitable ID for the /etc/localtime
+ // timezone.
+ // Sometimes /etc/localtime is a symlink to some
+ // /usr/share/zoneinfo/ file.
+ String id = null;
+ try
+ {
+ id = new File("/etc/localtime").getCanonicalPath();
+ if (id != null)
+ {
+ String zoneinfo_dir
+ = SystemProperties.getProperty("gnu.java.util.zoneinfo.dir");
+ if (zoneinfo_dir != null)
+ zoneinfo_dir
+ = new File(zoneinfo_dir
+ + File.separatorChar).getCanonicalPath();
+ if (zoneinfo_dir != null && id.startsWith(zoneinfo_dir))
+ {
+ int pos = zoneinfo_dir.length();
+ while (pos < id.length()
+ && id.charAt(pos) == File.separatorChar)
+ pos++;
+ if (pos < id.length())
+ id = id.substring(pos);
+ else
+ id = null;
+ }
+ else
+ id = null;
+ }
+ }
+ catch (IOException ioe)
+ {
+ id = null;
+ }
+
+ if (id == null)
+ id = readSysconfigClockFile("/etc/sysconfig/clock");
+
+ if (id != null)
+ zone.setID(id);
+ }
+ }
+
+ // Try some system specific way
+ if (zone == null)
+ {
+ tzid = getSystemTimeZoneId();
+ if (tzid != null && !tzid.equals(""))
+ zone = TimeZone.getDefaultTimeZone(tzid);
+ }
+
+ return zone;
+ }
+
+ /**
+ * Tries to read the time zone name from a file. Only the first
+ * consecutive letters, digits, slashes, dashes and underscores are
+ * read from the file. If the file cannot be read or an IOException
+ * occurs null is returned.
+ * <p>
+ * The /etc/timezone file is not standard, but a lot of systems have
+ * it. If it exist the first line always contains a string
+ * describing the timezone of the host of domain. Some systems
+ * contain a /etc/TIMEZONE file which is used to set the TZ
+ * environment variable (which is checked before /etc/timezone is
+ * read).
+ */
+ private static String readTimeZoneFile(String file)
+ {
+ File f = new File(file);
+ if (!f.exists())
+ return null;
+
+ InputStreamReader isr = null;
+ try
+ {
+ FileInputStream fis = new FileInputStream(f);
+ BufferedInputStream bis = new BufferedInputStream(fis);
+ isr = new InputStreamReader(bis);
+
+ StringBuffer sb = new StringBuffer();
+ int i = isr.read();
+ while (i != -1)
+ {
+ char c = (char) i;
+ if (Character.isLetter(c) || Character.isDigit(c)
+ || c == '/' || c == '-' || c == '_')
+ {
+ sb.append(c);
+ i = isr.read();
+ }
+ else
+ break;
+ }
+ return sb.toString();
+ }
+ catch (IOException ioe)
+ {
+ // Parse error, not a proper tzfile.
+ return null;
+ }
+ finally
+ {
+ try
+ {
+ if (isr != null)
+ isr.close();
+ }
+ catch (IOException ioe)
+ {
+ // Error while close, nothing we can do.
+ }
+ }
+ }
+
+ /**
+ * Tries to read the time zone name from a file.
+ * If the file cannot be read or an IOException occurs null is returned.
+ * <p>
+ * The /etc/sysconfig/clock file is not standard, but a lot of systems
+ * have it. The file is included by shell scripts and the timezone
+ * name is defined in ZONE variable.
+ * This routine should grok it with or without quotes:
+ * ZONE=America/New_York
+ * or
+ * ZONE="Europe/London"
+ */
+ private static String readSysconfigClockFile(String file)
+ {
+ BufferedReader br = null;
+ try
+ {
+ FileInputStream fis = new FileInputStream(file);
+ BufferedInputStream bis = new BufferedInputStream(fis);
+ br = new BufferedReader(new InputStreamReader(bis));
+
+ for (String line = br.readLine(); line != null; line = br.readLine())
+ {
+ line = line.trim();
+ if (line.length() < 8 || !line.startsWith("ZONE="))
+ continue;
+ int posstart = 6;
+ int posend;
+ if (line.charAt(5) == '"')
+ posend = line.indexOf('"', 6);
+ else if (line.charAt(5) == '\'')
+ posend = line.indexOf('\'', 6);
+ else
+ {
+ posstart = 5;
+ posend = line.length();
+ }
+ if (posend < 0)
+ return null;
+ return line.substring(posstart, posend);
+ }
+ return null;
+ }
+ catch (IOException ioe)
+ {
+ // Parse error, not a proper tzfile.
+ return null;
+ }
+ finally
+ {
+ try
+ {
+ if (br != null)
+ br.close();
+ }
+ catch (IOException ioe)
+ {
+ // Error while close, nothing we can do.
+ }
+ }
+ }
+
+ /**
+ * Tries to get the system time zone id through native code.
+ */
+ private static native String getSystemTimeZoneId();
+}