| /* |
| * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved. |
| * 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. |
| */ |
| |
| package sun.net.dns; |
| |
| import java.util.List; |
| import java.util.LinkedList; |
| import java.util.StringTokenizer; |
| import java.io.BufferedReader; |
| import java.io.FileReader; |
| import java.io.IOException; |
| |
| /* |
| * An implementation of ResolverConfiguration for Solaris |
| * and Linux. |
| */ |
| |
| public class ResolverConfigurationImpl |
| extends ResolverConfiguration |
| { |
| // Lock helds whilst loading configuration or checking |
| private static Object lock = new Object(); |
| |
| // Time of last refresh. |
| private static long lastRefresh = -1; |
| |
| // Cache timeout (300 seconds) - should be converted into property |
| // or configured as preference in the future. |
| private static final int TIMEOUT = 300000; |
| |
| // Resolver options |
| private final Options opts; |
| |
| // Parse /etc/resolv.conf to get the values for a particular |
| // keyword. |
| // |
| private LinkedList<String> resolvconf(String keyword, |
| int maxperkeyword, |
| int maxkeywords) |
| { |
| LinkedList<String> ll = new LinkedList<>(); |
| |
| try { |
| BufferedReader in = |
| new BufferedReader(new FileReader("/etc/resolv.conf")); |
| String line; |
| while ((line = in.readLine()) != null) { |
| int maxvalues = maxperkeyword; |
| if (line.length() == 0) |
| continue; |
| if (line.charAt(0) == '#' || line.charAt(0) == ';') |
| continue; |
| if (!line.startsWith(keyword)) |
| continue; |
| String value = line.substring(keyword.length()); |
| if (value.length() == 0) |
| continue; |
| if (value.charAt(0) != ' ' && value.charAt(0) != '\t') |
| continue; |
| StringTokenizer st = new StringTokenizer(value, " \t"); |
| while (st.hasMoreTokens()) { |
| String val = st.nextToken(); |
| if (val.charAt(0) == '#' || val.charAt(0) == ';') { |
| break; |
| } |
| ll.add(val); |
| if (--maxvalues == 0) { |
| break; |
| } |
| } |
| if (--maxkeywords == 0) { |
| break; |
| } |
| } |
| in.close(); |
| } catch (IOException ioe) { |
| // problem reading value |
| } |
| |
| return ll; |
| } |
| |
| private LinkedList<String> searchlist; |
| private LinkedList<String> nameservers; |
| |
| |
| // Load DNS configuration from OS |
| |
| private void loadConfig() { |
| assert Thread.holdsLock(lock); |
| |
| // check if cached settings have expired. |
| if (lastRefresh >= 0) { |
| long currTime = System.currentTimeMillis(); |
| if ((currTime - lastRefresh) < TIMEOUT) { |
| return; |
| } |
| } |
| |
| // get the name servers from /etc/resolv.conf |
| nameservers = |
| java.security.AccessController.doPrivileged( |
| new java.security.PrivilegedAction<LinkedList<String>>() { |
| public LinkedList<String> run() { |
| // typically MAXNS is 3 but we've picked 5 here |
| // to allow for additional servers if required. |
| return resolvconf("nameserver", 1, 5); |
| } /* run */ |
| }); |
| |
| // get the search list (or domain) |
| searchlist = getSearchList(); |
| |
| // update the timestamp on the configuration |
| lastRefresh = System.currentTimeMillis(); |
| } |
| |
| |
| // obtain search list or local domain |
| |
| private LinkedList<String> getSearchList() { |
| |
| LinkedList<String> sl; |
| |
| // first try the search keyword in /etc/resolv.conf |
| |
| sl = java.security.AccessController.doPrivileged( |
| new java.security.PrivilegedAction<LinkedList<String>>() { |
| public LinkedList<String> run() { |
| LinkedList ll; |
| |
| // first try search keyword (max 6 domains) |
| ll = resolvconf("search", 6, 1); |
| if (ll.size() > 0) { |
| return ll; |
| } |
| |
| return null; |
| |
| } /* run */ |
| |
| }); |
| if (sl != null) { |
| return sl; |
| } |
| |
| // No search keyword so use local domain |
| |
| |
| // LOCALDOMAIN has absolute priority on Solaris |
| |
| String localDomain = localDomain0(); |
| if (localDomain != null && localDomain.length() > 0) { |
| sl = new LinkedList(); |
| sl.add(localDomain); |
| return sl; |
| } |
| |
| // try domain keyword in /etc/resolv.conf |
| |
| sl = java.security.AccessController.doPrivileged( |
| new java.security.PrivilegedAction<LinkedList<String>>() { |
| public LinkedList<String> run() { |
| LinkedList<String> ll; |
| |
| ll = resolvconf("domain", 1, 1); |
| if (ll.size() > 0) { |
| return ll; |
| } |
| return null; |
| |
| } /* run */ |
| }); |
| if (sl != null) { |
| return sl; |
| } |
| |
| // no local domain so try fallback (RPC) domain or |
| // hostname |
| |
| sl = new LinkedList<>(); |
| String domain = fallbackDomain0(); |
| if (domain != null && domain.length() > 0) { |
| sl.add(domain); |
| } |
| |
| return sl; |
| } |
| |
| |
| // ---- |
| |
| ResolverConfigurationImpl() { |
| opts = new OptionsImpl(); |
| } |
| |
| public List<String> searchlist() { |
| synchronized (lock) { |
| loadConfig(); |
| |
| // List is mutable so return a shallow copy |
| return (List)searchlist.clone(); |
| } |
| } |
| |
| public List<String> nameservers() { |
| synchronized (lock) { |
| loadConfig(); |
| |
| // List is mutable so return a shallow copy |
| return (List)nameservers.clone(); |
| } |
| } |
| |
| public Options options() { |
| return opts; |
| } |
| |
| |
| // --- Native methods -- |
| |
| static native String localDomain0(); |
| |
| static native String fallbackDomain0(); |
| |
| static { |
| java.security.AccessController.doPrivileged( |
| new sun.security.action.LoadLibraryAction("net")); |
| } |
| |
| } |
| |
| /** |
| * Implementation of {@link ResolverConfiguration.Options} |
| */ |
| class OptionsImpl extends ResolverConfiguration.Options { |
| } |