src/org/xbill/DNS/ResolverConfig.java - platform/external/smack - Git at Google

 // Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)

 package org.xbill.DNS;

 import java.io.*;
 import java.lang.reflect.*;
 import java.util.*;

 /**
  * A class that tries to locate name servers and the search path to
  * be appended to unqualified names.
  *
  * The following are attempted, in order, until one succeeds.
  * <UL>
  *   <LI>The properties 'dns.server' and 'dns.search' (comma delimited lists)
  *       are checked.  The servers can either be IP addresses or hostnames
  *       (which are resolved using Java's built in DNS support).
  *   <LI>The sun.net.dns.ResolverConfiguration class is queried.
  *   <LI>On Unix, /etc/resolv.conf is parsed.
  *   <LI>On Windows, ipconfig/winipcfg is called and its output parsed.  This
  *       may fail for non-English versions on Windows.
  *   <LI>"localhost" is used as the nameserver, and the search path is empty.
  * </UL>
  *
  * These routines will be called internally when creating Resolvers/Lookups
  * without explicitly specifying server names, and can also be called
  * directly if desired.
  *
  * @author Brian Wellington
  * @author <a href="mailto:yannick@meudal.net">Yannick Meudal</a>
  * @author <a href="mailto:arnt@gulbrandsen.priv.no">Arnt Gulbrandsen</a>
  */

 public class ResolverConfig {

 private String [] servers = null;
 private Name [] searchlist = null;
 private int ndots = -1;

 private static ResolverConfig currentConfig;

 static {
 	refresh();
 }

 public
 ResolverConfig() {
 	if (findProperty())
 		return;
 	if (findSunJVM())
 		return;
 	if (servers == null || searchlist == null) {
 		String OS = System.getProperty("os.name");
 		String vendor = System.getProperty("java.vendor");
 		if (OS.indexOf("Windows") != -1) {
 			if (OS.indexOf("95") != -1 ||
 			    OS.indexOf("98") != -1 ||
 			    OS.indexOf("ME") != -1)
 				find95();
 			else
 				findNT();
 		} else if (OS.indexOf("NetWare") != -1) {
 			findNetware();
 		} else if (vendor.indexOf("Android") != -1) {
 			findAndroid();
 		} else {
 			findUnix();
 		}
 	}
 }

 private void
 addServer(String server, List list) {
 	if (list.contains(server))
 		return;
 	if (Options.check("verbose"))
 		System.out.println("adding server " + server);
 	list.add(server);
 }

 private void
 addSearch(String search, List list) {
 	Name name;
 	if (Options.check("verbose"))
 		System.out.println("adding search " + search);
 	try {
 		name = Name.fromString(search, Name.root);
 	}
 	catch (TextParseException e) {
 		return;
 	}
 	if (list.contains(name))
 		return;
 	list.add(name);
 }

 private int
 parseNdots(String token) {
 	token = token.substring(6);
 	try {
 		int ndots = Integer.parseInt(token);
 		if (ndots >= 0) {
 			if (Options.check("verbose"))
 				System.out.println("setting ndots " + token);
 			return ndots;
 		}
 	}
 	catch (NumberFormatException e) {
 	}
 	return -1;
 }

 private void
 configureFromLists(List lserver, List lsearch) {
 	if (servers == null && lserver.size() > 0)
 		servers = (String []) lserver.toArray(new String[0]);
 	if (searchlist == null && lsearch.size() > 0)
 		searchlist = (Name []) lsearch.toArray(new Name[0]);
 }

 private void
 configureNdots(int lndots) {
 	if (ndots < 0 && lndots > 0)
 		ndots = lndots;
 }

 /**
  * Looks in the system properties to find servers and a search path.
  * Servers are defined by dns.server=server1,server2...
  * The search path is defined by dns.search=domain1,domain2...
  */
 private boolean
 findProperty() {
 	String prop;
 	List lserver = new ArrayList(0);
 	List lsearch = new ArrayList(0);
 	StringTokenizer st;

 	prop = System.getProperty("dns.server");
 	if (prop != null) {
 		st = new StringTokenizer(prop, ",");
 		while (st.hasMoreTokens())
 			addServer(st.nextToken(), lserver);
 	}

 	prop = System.getProperty("dns.search");
 	if (prop != null) {
 		st = new StringTokenizer(prop, ",");
 		while (st.hasMoreTokens())
 			addSearch(st.nextToken(), lsearch);
 	}
 	configureFromLists(lserver, lsearch);
 	return (servers != null && searchlist != null);
 }

 /**
  * Uses the undocumented Sun DNS implementation to determine the configuration.
  * This doesn't work or even compile with all JVMs (gcj, for example).
  */
 private boolean
 findSunJVM() {
 	List lserver = new ArrayList(0);
 	List lserver_tmp;
 	List lsearch = new ArrayList(0);
 	List lsearch_tmp;

 	try {
 		Class [] noClasses = new Class[0];
 		Object [] noObjects = new Object[0];
 		String resConfName = "sun.net.dns.ResolverConfiguration";
 		Class resConfClass = Class.forName(resConfName);
 		Object resConf;

 		// ResolverConfiguration resConf = ResolverConfiguration.open();
 		Method open = resConfClass.getDeclaredMethod("open", noClasses);
 		resConf = open.invoke(null, noObjects);

 		// lserver_tmp = resConf.nameservers();
 		Method nameservers = resConfClass.getMethod("nameservers",
 							    noClasses);
 		lserver_tmp = (List) nameservers.invoke(resConf, noObjects);

 		// lsearch_tmp = resConf.searchlist();
 		Method searchlist = resConfClass.getMethod("searchlist",
 							    noClasses);
 		lsearch_tmp = (List) searchlist.invoke(resConf, noObjects);
 	}
 	catch (Exception e) {
 		return false;
 	}

 	if (lserver_tmp.size() == 0)
 		return false;

 	if (lserver_tmp.size() > 0) {
 		Iterator it = lserver_tmp.iterator();
 		while (it.hasNext())
 			addServer((String) it.next(), lserver);
 	}

 	if (lsearch_tmp.size() > 0) {
 		Iterator it = lsearch_tmp.iterator();
 		while (it.hasNext())
 			addSearch((String) it.next(), lsearch);
 	}
 	configureFromLists(lserver, lsearch);
 	return true;
 }

 /**
  * Looks in /etc/resolv.conf to find servers and a search path.
  * "nameserver" lines specify servers.  "domain" and "search" lines
  * define the search path.
  */
 private void
 findResolvConf(String file) {
 	InputStream in = null;
 	try {
 		in = new FileInputStream(file);
 	}
 	catch (FileNotFoundException e) {
 		return;
 	}
 	InputStreamReader isr = new InputStreamReader(in);
 	BufferedReader br = new BufferedReader(isr);
 	List lserver = new ArrayList(0);
 	List lsearch = new ArrayList(0);
 	int lndots = -1;
 	try {
 		String line;
 		while ((line = br.readLine()) != null) {
 			if (line.startsWith("nameserver")) {
 				StringTokenizer st = new StringTokenizer(line);
 				st.nextToken(); /* skip nameserver */
 				addServer(st.nextToken(), lserver);
 			}
 			else if (line.startsWith("domain")) {
 				StringTokenizer st = new StringTokenizer(line);
 				st.nextToken(); /* skip domain */
 				if (!st.hasMoreTokens())
 					continue;
 				if (lsearch.isEmpty())
 					addSearch(st.nextToken(), lsearch);
 			}
 			else if (line.startsWith("search")) {
 				if (!lsearch.isEmpty())
 					lsearch.clear();
 				StringTokenizer st = new StringTokenizer(line);
 				st.nextToken(); /* skip search */
 				while (st.hasMoreTokens())
 					addSearch(st.nextToken(), lsearch);
 			}
 			else if(line.startsWith("options")) {
 				StringTokenizer st = new StringTokenizer(line);
 				st.nextToken(); /* skip options */
 				while (st.hasMoreTokens()) {
 					String token = st.nextToken();
 					if (token.startsWith("ndots:")) {
 						lndots = parseNdots(token);
 					}
 				}
 			}
 		}
 		br.close();
 	}
 	catch (IOException e) {
 	}

 	configureFromLists(lserver, lsearch);
 	configureNdots(lndots);
 }

 private void
 findUnix() {
 	findResolvConf("/etc/resolv.conf");
 }

 private void
 findNetware() {
 	findResolvConf("sys:/etc/resolv.cfg");
 }

 /**
  * Parses the output of winipcfg or ipconfig.
  */
 private void
 findWin(InputStream in, Locale locale) {
 	String packageName = ResolverConfig.class.getPackage().getName();
 	String resPackageName = packageName + ".windows.DNSServer";
 	ResourceBundle res;
 	if (locale != null)
 		res = ResourceBundle.getBundle(resPackageName, locale);
 	else
 		res = ResourceBundle.getBundle(resPackageName);

 	String host_name = res.getString("host_name");
 	String primary_dns_suffix = res.getString("primary_dns_suffix");
 	String dns_suffix = res.getString("dns_suffix");
 	String dns_servers = res.getString("dns_servers");

 	BufferedReader br = new BufferedReader(new InputStreamReader(in));
 	try {
 		List lserver = new ArrayList();
 		List lsearch = new ArrayList();
 		String line = null;
 		boolean readingServers = false;
 		boolean readingSearches = false;
 		while ((line = br.readLine()) != null) {
 			StringTokenizer st = new StringTokenizer(line);
 			if (!st.hasMoreTokens()) {
 				readingServers = false;
 				readingSearches = false;
 				continue;
 			}
 			String s = st.nextToken();
 			if (line.indexOf(":") != -1) {
 				readingServers = false;
 				readingSearches = false;
 			}

 			if (line.indexOf(host_name) != -1) {
 				while (st.hasMoreTokens())
 					s = st.nextToken();
 				Name name;
 				try {
 					name = Name.fromString(s, null);
 				}
 				catch (TextParseException e) {
 					continue;
 				}
 				if (name.labels() == 1)
 					continue;
 				addSearch(s, lsearch);
 			} else if (line.indexOf(primary_dns_suffix) != -1) {
 				while (st.hasMoreTokens())
 					s = st.nextToken();
 				if (s.equals(":"))
 					continue;
 				addSearch(s, lsearch);
 				readingSearches = true;
 			} else if (readingSearches ||
 				   line.indexOf(dns_suffix) != -1)
 			{
 				while (st.hasMoreTokens())
 					s = st.nextToken();
 				if (s.equals(":"))
 					continue;
 				addSearch(s, lsearch);
 				readingSearches = true;
 			} else if (readingServers ||
 				   line.indexOf(dns_servers) != -1)
 			{
 				while (st.hasMoreTokens())
 					s = st.nextToken();
 				if (s.equals(":"))
 					continue;
 				addServer(s, lserver);
 				readingServers = true;
 			}
 		}

 		configureFromLists(lserver, lsearch);
 	}
 	catch (IOException e) {
 	}
 	return;
 }

 private void
 findWin(InputStream in) {
 	String property = "org.xbill.DNS.windows.parse.buffer";
 	final int defaultBufSize = 8 * 1024;
 	int bufSize = Integer.getInteger(property, defaultBufSize).intValue();
 	BufferedInputStream b = new BufferedInputStream(in, bufSize);
 	b.mark(bufSize);
 	findWin(b, null);
 	if (servers == null) {
 		try {
 			b.reset();
 		}
 		catch (IOException e) {
 			return;
 		}
 		findWin(b, new Locale("", ""));
 	}
 }

 /**
  * Calls winipcfg and parses the result to find servers and a search path.
  */
 private void
 find95() {
 	String s = "winipcfg.out";
 	try {
 		Process p;
 		p = Runtime.getRuntime().exec("winipcfg /all /batch " + s);
 		p.waitFor();
 		File f = new File(s);
 		findWin(new FileInputStream(f));
 		new File(s).delete();
 	}
 	catch (Exception e) {
 		return;
 	}
 }

 /**
  * Calls ipconfig and parses the result to find servers and a search path.
  */
 private void
 findNT() {
 	try {
 		Process p;
 		p = Runtime.getRuntime().exec("ipconfig /all");
 		findWin(p.getInputStream());
 		p.destroy();
 	}
 	catch (Exception e) {
 		return;
 	}
 }

 /**
  * Parses the output of getprop, which is the only way to get DNS
  * info on Android. getprop might disappear in future releases, so
  * this code comes with a use-by date.
  */
 private void
 findAndroid() {
 	// This originally looked for all lines containing .dns; but
 	// http://code.google.com/p/android/issues/detail?id=2207#c73
 	// indicates that net.dns* should always be the active nameservers, so
 	// we use those.
 	String re1 = "^\\d+(\\.\\d+){3}$";
 	String re2 = "^[0-9a-f]+(:[0-9a-f]*)+:[0-9a-f]+$";
 	try {
 		ArrayList lserver = new ArrayList();
 		ArrayList lsearch = new ArrayList();
 		String line;
 		Process p = Runtime.getRuntime().exec("getprop");
 		InputStream in = p.getInputStream();
 		InputStreamReader isr = new InputStreamReader(in);
 		BufferedReader br = new BufferedReader(isr);
 		while ((line = br.readLine()) != null ) {
 			StringTokenizer t = new StringTokenizer(line, ":");
 			String name = t.nextToken();
 			if (name.indexOf( "net.dns" ) > -1) {
 				String v = t.nextToken();
 				v = v.replaceAll("[ \\[\\]]", "");
 				if ((v.matches(re1) || v.matches(re2)) &&
 				    !lserver.contains(v))
 					lserver.add(v);
 			}
 		}
 		configureFromLists(lserver, lsearch);
 	} catch ( Exception e ) {
 		// ignore resolutely
 	}
 }

 /** Returns all located servers */
 public String []
 servers() {
 	return servers;
 }

 /** Returns the first located server */
 public String
 server() {
 	if (servers == null)
 		return null;
 	return servers[0];
 }

 /** Returns all entries in the located search path */
 public Name []
 searchPath() {
 	return searchlist;
 }

 /**
  * Returns the located ndots value, or the default (1) if not configured.
  * Note that ndots can only be configured in a resolv.conf file, and will only
  * take effect if ResolverConfig uses resolv.conf directly (that is, if the
  * JVM does not include the sun.net.dns.ResolverConfiguration class).
  */
 public int
 ndots() {
 	if (ndots < 0)
 		return 1;
 	return ndots;
 }

 /** Gets the current configuration */
 public static synchronized ResolverConfig
 getCurrentConfig() {
 	return currentConfig;
 }

 /** Gets the current configuration */
 public static void
 refresh() {
 	ResolverConfig newConfig = new ResolverConfig();
 	synchronized (ResolverConfig.class) {
 		currentConfig = newConfig;
 	}
 }

 }
	// Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)

	package org.xbill.DNS;

	import java.io.*;
	import java.lang.reflect.*;
	import java.util.*;

	/**
	* A class that tries to locate name servers and the search path to
	* be appended to unqualified names.
	*
	* The following are attempted, in order, until one succeeds.
	* <UL>
	* <LI>The properties 'dns.server' and 'dns.search' (comma delimited lists)
	* are checked. The servers can either be IP addresses or hostnames
	* (which are resolved using Java's built in DNS support).
	* <LI>The sun.net.dns.ResolverConfiguration class is queried.
	* <LI>On Unix, /etc/resolv.conf is parsed.
	* <LI>On Windows, ipconfig/winipcfg is called and its output parsed. This
	* may fail for non-English versions on Windows.
	* <LI>"localhost" is used as the nameserver, and the search path is empty.
	* </UL>
	*
	* These routines will be called internally when creating Resolvers/Lookups
	* without explicitly specifying server names, and can also be called
	* directly if desired.
	*
	* @author Brian Wellington
	* @author <a href="mailto:yannick@meudal.net">Yannick Meudal</a>
	* @author <a href="mailto:arnt@gulbrandsen.priv.no">Arnt Gulbrandsen</a>
	*/

	public class ResolverConfig {

	private String [] servers = null;
	private Name [] searchlist = null;
	private int ndots = -1;

	private static ResolverConfig currentConfig;

	static {
	refresh();
	}

	public
	ResolverConfig() {
	if (findProperty())
	return;
	if (findSunJVM())
	return;
	if (servers == null \|\| searchlist == null) {
	String OS = System.getProperty("os.name");
	String vendor = System.getProperty("java.vendor");
	if (OS.indexOf("Windows") != -1) {
	if (OS.indexOf("95") != -1 \|\|
	OS.indexOf("98") != -1 \|\|
	OS.indexOf("ME") != -1)
	find95();
	else
	findNT();
	} else if (OS.indexOf("NetWare") != -1) {
	findNetware();
	} else if (vendor.indexOf("Android") != -1) {
	findAndroid();
	} else {
	findUnix();
	}
	}
	}

	private void
	addServer(String server, List list) {
	if (list.contains(server))
	return;
	if (Options.check("verbose"))
	System.out.println("adding server " + server);
	list.add(server);
	}

	private void
	addSearch(String search, List list) {
	Name name;
	if (Options.check("verbose"))
	System.out.println("adding search " + search);
	try {
	name = Name.fromString(search, Name.root);
	}
	catch (TextParseException e) {
	return;
	}
	if (list.contains(name))
	return;
	list.add(name);
	}

	private int
	parseNdots(String token) {
	token = token.substring(6);
	try {
	int ndots = Integer.parseInt(token);
	if (ndots >= 0) {
	if (Options.check("verbose"))
	System.out.println("setting ndots " + token);
	return ndots;
	}
	}
	catch (NumberFormatException e) {
	}
	return -1;
	}

	private void
	configureFromLists(List lserver, List lsearch) {
	if (servers == null && lserver.size() > 0)
	servers = (String []) lserver.toArray(new String[0]);
	if (searchlist == null && lsearch.size() > 0)
	searchlist = (Name []) lsearch.toArray(new Name[0]);
	}

	private void
	configureNdots(int lndots) {
	if (ndots < 0 && lndots > 0)
	ndots = lndots;
	}

	/**
	* Looks in the system properties to find servers and a search path.
	* Servers are defined by dns.server=server1,server2...
	* The search path is defined by dns.search=domain1,domain2...
	*/
	private boolean
	findProperty() {
	String prop;
	List lserver = new ArrayList(0);
	List lsearch = new ArrayList(0);
	StringTokenizer st;

	prop = System.getProperty("dns.server");
	if (prop != null) {
	st = new StringTokenizer(prop, ",");
	while (st.hasMoreTokens())
	addServer(st.nextToken(), lserver);
	}

	prop = System.getProperty("dns.search");
	if (prop != null) {
	st = new StringTokenizer(prop, ",");
	while (st.hasMoreTokens())
	addSearch(st.nextToken(), lsearch);
	}
	configureFromLists(lserver, lsearch);
	return (servers != null && searchlist != null);
	}

	/**
	* Uses the undocumented Sun DNS implementation to determine the configuration.
	* This doesn't work or even compile with all JVMs (gcj, for example).
	*/
	private boolean
	findSunJVM() {
	List lserver = new ArrayList(0);
	List lserver_tmp;
	List lsearch = new ArrayList(0);
	List lsearch_tmp;

	try {
	Class [] noClasses = new Class[0];
	Object [] noObjects = new Object[0];
	String resConfName = "sun.net.dns.ResolverConfiguration";
	Class resConfClass = Class.forName(resConfName);
	Object resConf;

	// ResolverConfiguration resConf = ResolverConfiguration.open();
	Method open = resConfClass.getDeclaredMethod("open", noClasses);
	resConf = open.invoke(null, noObjects);

	// lserver_tmp = resConf.nameservers();
	Method nameservers = resConfClass.getMethod("nameservers",
	noClasses);
	lserver_tmp = (List) nameservers.invoke(resConf, noObjects);

	// lsearch_tmp = resConf.searchlist();
	Method searchlist = resConfClass.getMethod("searchlist",
	noClasses);
	lsearch_tmp = (List) searchlist.invoke(resConf, noObjects);
	}
	catch (Exception e) {
	return false;
	}

	if (lserver_tmp.size() == 0)
	return false;

	if (lserver_tmp.size() > 0) {
	Iterator it = lserver_tmp.iterator();
	while (it.hasNext())
	addServer((String) it.next(), lserver);
	}

	if (lsearch_tmp.size() > 0) {
	Iterator it = lsearch_tmp.iterator();
	while (it.hasNext())
	addSearch((String) it.next(), lsearch);
	}
	configureFromLists(lserver, lsearch);
	return true;
	}

	/**
	* Looks in /etc/resolv.conf to find servers and a search path.
	* "nameserver" lines specify servers. "domain" and "search" lines
	* define the search path.
	*/
	private void
	findResolvConf(String file) {
	InputStream in = null;
	try {
	in = new FileInputStream(file);
	}
	catch (FileNotFoundException e) {
	return;
	}
	InputStreamReader isr = new InputStreamReader(in);
	BufferedReader br = new BufferedReader(isr);
	List lserver = new ArrayList(0);
	List lsearch = new ArrayList(0);
	int lndots = -1;
	try {
	String line;
	while ((line = br.readLine()) != null) {
	if (line.startsWith("nameserver")) {
	StringTokenizer st = new StringTokenizer(line);
	st.nextToken(); /* skip nameserver */
	addServer(st.nextToken(), lserver);
	}
	else if (line.startsWith("domain")) {
	StringTokenizer st = new StringTokenizer(line);
	st.nextToken(); /* skip domain */
	if (!st.hasMoreTokens())
	continue;
	if (lsearch.isEmpty())
	addSearch(st.nextToken(), lsearch);
	}
	else if (line.startsWith("search")) {
	if (!lsearch.isEmpty())
	lsearch.clear();
	StringTokenizer st = new StringTokenizer(line);
	st.nextToken(); /* skip search */
	while (st.hasMoreTokens())
	addSearch(st.nextToken(), lsearch);
	}
	else if(line.startsWith("options")) {
	StringTokenizer st = new StringTokenizer(line);
	st.nextToken(); /* skip options */
	while (st.hasMoreTokens()) {
	String token = st.nextToken();
	if (token.startsWith("ndots:")) {
	lndots = parseNdots(token);
	}
	}
	}
	}
	br.close();
	}
	catch (IOException e) {
	}

	configureFromLists(lserver, lsearch);
	configureNdots(lndots);
	}

	private void
	findUnix() {
	findResolvConf("/etc/resolv.conf");
	}

	private void
	findNetware() {
	findResolvConf("sys:/etc/resolv.cfg");
	}

	/**
	* Parses the output of winipcfg or ipconfig.
	*/
	private void
	findWin(InputStream in, Locale locale) {
	String packageName = ResolverConfig.class.getPackage().getName();
	String resPackageName = packageName + ".windows.DNSServer";
	ResourceBundle res;
	if (locale != null)
	res = ResourceBundle.getBundle(resPackageName, locale);
	else
	res = ResourceBundle.getBundle(resPackageName);

	String host_name = res.getString("host_name");
	String primary_dns_suffix = res.getString("primary_dns_suffix");
	String dns_suffix = res.getString("dns_suffix");
	String dns_servers = res.getString("dns_servers");

	BufferedReader br = new BufferedReader(new InputStreamReader(in));
	try {
	List lserver = new ArrayList();
	List lsearch = new ArrayList();
	String line = null;
	boolean readingServers = false;
	boolean readingSearches = false;
	while ((line = br.readLine()) != null) {
	StringTokenizer st = new StringTokenizer(line);
	if (!st.hasMoreTokens()) {
	readingServers = false;
	readingSearches = false;
	continue;
	}
	String s = st.nextToken();
	if (line.indexOf(":") != -1) {
	readingServers = false;
	readingSearches = false;
	}

	if (line.indexOf(host_name) != -1) {
	while (st.hasMoreTokens())
	s = st.nextToken();
	Name name;
	try {
	name = Name.fromString(s, null);
	}
	catch (TextParseException e) {
	continue;
	}
	if (name.labels() == 1)
	continue;
	addSearch(s, lsearch);
	} else if (line.indexOf(primary_dns_suffix) != -1) {
	while (st.hasMoreTokens())
	s = st.nextToken();
	if (s.equals(":"))
	continue;
	addSearch(s, lsearch);
	readingSearches = true;
	} else if (readingSearches \|\|
	line.indexOf(dns_suffix) != -1)
	{
	while (st.hasMoreTokens())
	s = st.nextToken();
	if (s.equals(":"))
	continue;
	addSearch(s, lsearch);
	readingSearches = true;
	} else if (readingServers \|\|
	line.indexOf(dns_servers) != -1)
	{
	while (st.hasMoreTokens())
	s = st.nextToken();
	if (s.equals(":"))
	continue;
	addServer(s, lserver);
	readingServers = true;
	}
	}

	configureFromLists(lserver, lsearch);
	}
	catch (IOException e) {
	}
	return;
	}

	private void
	findWin(InputStream in) {
	String property = "org.xbill.DNS.windows.parse.buffer";
	final int defaultBufSize = 8 * 1024;
	int bufSize = Integer.getInteger(property, defaultBufSize).intValue();
	BufferedInputStream b = new BufferedInputStream(in, bufSize);
	b.mark(bufSize);
	findWin(b, null);
	if (servers == null) {
	try {
	b.reset();
	}
	catch (IOException e) {
	return;
	}
	findWin(b, new Locale("", ""));
	}
	}

	/**
	* Calls winipcfg and parses the result to find servers and a search path.
	*/
	private void
	find95() {
	String s = "winipcfg.out";
	try {
	Process p;
	p = Runtime.getRuntime().exec("winipcfg /all /batch " + s);
	p.waitFor();
	File f = new File(s);
	findWin(new FileInputStream(f));
	new File(s).delete();
	}
	catch (Exception e) {
	return;
	}
	}

	/**
	* Calls ipconfig and parses the result to find servers and a search path.
	*/
	private void
	findNT() {
	try {
	Process p;
	p = Runtime.getRuntime().exec("ipconfig /all");
	findWin(p.getInputStream());
	p.destroy();
	}
	catch (Exception e) {
	return;
	}
	}

	/**
	* Parses the output of getprop, which is the only way to get DNS
	* info on Android. getprop might disappear in future releases, so
	* this code comes with a use-by date.
	*/
	private void
	findAndroid() {
	// This originally looked for all lines containing .dns; but
	// http://code.google.com/p/android/issues/detail?id=2207#c73
	// indicates that net.dns* should always be the active nameservers, so
	// we use those.
	String re1 = "^\\d+(\\.\\d+){3}$";
	String re2 = "^[0-9a-f]+(:[0-9a-f]*)+:[0-9a-f]+$";
	try {
	ArrayList lserver = new ArrayList();
	ArrayList lsearch = new ArrayList();
	String line;
	Process p = Runtime.getRuntime().exec("getprop");
	InputStream in = p.getInputStream();
	InputStreamReader isr = new InputStreamReader(in);
	BufferedReader br = new BufferedReader(isr);
	while ((line = br.readLine()) != null ) {
	StringTokenizer t = new StringTokenizer(line, ":");
	String name = t.nextToken();
	if (name.indexOf( "net.dns" ) > -1) {
	String v = t.nextToken();
	v = v.replaceAll("[ \\[\\]]", "");
	if ((v.matches(re1) \|\| v.matches(re2)) &&
	!lserver.contains(v))
	lserver.add(v);
	}
	}
	configureFromLists(lserver, lsearch);
	} catch ( Exception e ) {
	// ignore resolutely
	}
	}

	/** Returns all located servers */
	public String []
	servers() {
	return servers;
	}

	/** Returns the first located server */
	public String
	server() {
	if (servers == null)
	return null;
	return servers[0];
	}

	/** Returns all entries in the located search path */
	public Name []
	searchPath() {
	return searchlist;
	}

	/**
	* Returns the located ndots value, or the default (1) if not configured.
	* Note that ndots can only be configured in a resolv.conf file, and will only
	* take effect if ResolverConfig uses resolv.conf directly (that is, if the
	* JVM does not include the sun.net.dns.ResolverConfiguration class).
	*/
	public int
	ndots() {
	if (ndots < 0)
	return 1;
	return ndots;
	}

	/** Gets the current configuration */
	public static synchronized ResolverConfig
	getCurrentConfig() {
	return currentConfig;
	}

	/** Gets the current configuration */
	public static void
	refresh() {
	ResolverConfig newConfig = new ResolverConfig();
	synchronized (ResolverConfig.class) {
	currentConfig = newConfig;
	}
	}

	}