1 /* 2 * Copyright (c) 2020, Red Hat Inc. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package jdk.internal.platform; 27 28 import java.io.BufferedReader; 29 import java.io.IOException; 30 import java.nio.file.Files; 31 import java.nio.file.Path; 32 import java.nio.file.Paths; 33 import java.security.AccessController; 34 import java.security.PrivilegedActionException; 35 import java.security.PrivilegedExceptionAction; 36 import java.util.List; 37 import java.util.stream.Stream; 38 39 public final class CgroupUtil { 40 41 public static Stream<String> readFilePrivileged(Path path) throws IOException { 42 try { 43 PrivilegedExceptionAction<Stream<String>> pea = () -> Files.lines(path); 44 return AccessController.doPrivileged(pea); 45 } catch (PrivilegedActionException e) { 46 unwrapIOExceptionAndRethrow(e); 47 throw new InternalError(e.getCause()); 48 } 49 } 50 51 static void unwrapIOExceptionAndRethrow(PrivilegedActionException pae) throws IOException { 52 Throwable x = pae.getCause(); 53 if (x instanceof IOException) 54 throw (IOException) x; 55 if (x instanceof RuntimeException) 56 throw (RuntimeException) x; 57 if (x instanceof Error) 58 throw (Error) x; 59 } 60 61 static String readStringValue(CgroupSubsystemController controller, String param) throws IOException { 62 PrivilegedExceptionAction<BufferedReader> pea = () -> 63 Files.newBufferedReader(Paths.get(controller.path(), param)); 64 try (BufferedReader bufferedReader = 65 AccessController.doPrivileged(pea)) { 66 String line = bufferedReader.readLine(); 67 return line; 68 } catch (PrivilegedActionException e) { 69 unwrapIOExceptionAndRethrow(e); 70 throw new InternalError(e.getCause()); 71 } 72 } 73 74 static List<String> readAllLinesPrivileged(Path path) throws IOException { 75 try { 76 PrivilegedExceptionAction<List<String>> pea = () -> Files.readAllLines(path); 77 return AccessController.doPrivileged(pea); 78 } catch (PrivilegedActionException e) { 79 unwrapIOExceptionAndRethrow(e); 80 throw new InternalError(e.getCause()); 81 } 82 } 83 }