| /* |
| */ |
| package org.apache.taverna.server.unixforker; |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| import static java.lang.System.err; |
| import static java.lang.System.getProperty; |
| import static java.lang.System.in; |
| import static java.lang.System.out; |
| import static java.util.Arrays.asList; |
| |
| import java.io.BufferedReader; |
| import java.io.File; |
| import java.io.FileReader; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.InputStreamReader; |
| import java.io.OutputStream; |
| import java.io.OutputStreamWriter; |
| import java.util.List; |
| |
| import javax.annotation.Nonnull; |
| |
| /** |
| * A simple class that forks off processes when asked to over its standard |
| * input. The one complication is that it forks them off as other users, through |
| * the use of the <tt>sudo</tt> utility. It is Unix-specific. |
| * |
| * @author Donal Fellows |
| */ |
| public class Forker extends Thread { |
| private static String password; |
| private static BufferedReader br; |
| |
| /** |
| * Helper to make reading a password from a file clearer. The password must |
| * be the first line of the file. |
| * |
| * @param passwordFile |
| * The file to load from. |
| * @throws IOException |
| * If anything goes wrong. |
| */ |
| private static void loadPassword(@Nonnull File passwordFile) |
| throws IOException { |
| try { |
| err.println("attempting to load password from " + passwordFile); |
| try (FileReader fr = new FileReader(passwordFile)) { |
| password = new BufferedReader(fr).readLine(); |
| } |
| } catch (IOException e) { |
| err.println("failed to read password from file " + passwordFile |
| + "described in password.file property"); |
| throw e; |
| } |
| } |
| |
| /** |
| * Initialization code, which runs before the main loop starts processing. |
| * |
| * @param args |
| * The arguments to the program. |
| * @throws Exception |
| * If anything goes wrong. |
| */ |
| public static void init(String[] args) throws Exception { |
| if (args.length < 1) |
| throw new IllegalArgumentException( |
| "wrong # args: must be \"program ?argument ...?\""); |
| if (getProperty("password.file") != null) |
| loadPassword(new File(getProperty("password.file"))); |
| if (password == null) |
| err.println("no password.file property or empty file; " |
| + "assuming password-less sudo is configured"); |
| else |
| err.println("password is of length " + password.length()); |
| br = new BufferedReader(new InputStreamReader(in)); |
| } |
| |
| /** |
| * The body of the main loop of this program. |
| * |
| * @param args |
| * The arguments to use when running the other program. |
| * @return Whether to repeat the loop. |
| * @throws Exception |
| * If anything goes wrong. Note that the loop is repeated if an |
| * exception occurs in it. |
| */ |
| public static boolean mainLoopBody(String[] args) throws Exception { |
| String line = br.readLine(); |
| if (line == null) |
| return false; |
| List<String> vals = asList(line.split("[ \t]+")); |
| if (vals.size() != 2) { |
| out.println("wrong # values: must be \"username UUID\""); |
| return true; |
| } |
| ProcessBuilder pb = new ProcessBuilder(); |
| pb.command() |
| .addAll(asList("sudo", "-u", vals.get(0), "-S", "-H", "--")); |
| pb.command().addAll(asList(args)); |
| pb.command().add(vals.get(1)); |
| Forker f = new Forker(pb); |
| f.setDaemon(true); |
| f.start(); |
| return true; |
| } |
| |
| /** |
| * The main code for this class, which turns this into an executable |
| * program. Runs the initialisation and then the main loop, in both cases |
| * with appropriate error handling. |
| * |
| * @param args |
| * Arguments to this program. |
| */ |
| public static void main(String... args) { |
| try { |
| init(args); |
| while (true) { |
| try { |
| if (!mainLoopBody(args)) |
| break; |
| } catch (Exception e) { |
| e.printStackTrace(err); |
| out.println(e.getClass().getName() + ": " + e.getMessage()); |
| } |
| } |
| System.exit(0); |
| } catch (Exception e) { |
| e.printStackTrace(err); |
| System.exit(1); |
| } |
| } |
| |
| // -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- |
| |
| public Forker(ProcessBuilder pb) throws IOException { |
| out.println("Starting subprocess: " + pb.command()); |
| final Process p = pb.start(); |
| abstract class ProcessAttachedDaemon extends Thread { |
| public ProcessAttachedDaemon() { |
| setDaemon(true); |
| start(); |
| } |
| |
| abstract void act() throws Exception; |
| |
| @Override |
| public final void run() { |
| try { |
| act(); |
| p.waitFor(); |
| } catch (InterruptedException e) { |
| // Just drop |
| } catch (Exception e) { |
| p.destroy(); |
| e.printStackTrace(err); |
| } |
| } |
| } |
| new ProcessAttachedDaemon() { |
| @Override |
| void act() throws Exception { |
| copyFromSudo("Subprocess(out):", p.getInputStream()); |
| } |
| }; |
| new ProcessAttachedDaemon() { |
| @Override |
| void act() throws Exception { |
| copyFromSudo("Subprocess(err):", p.getErrorStream()); |
| } |
| }; |
| new ProcessAttachedDaemon() { |
| @Override |
| void act() throws Exception { |
| interactWithSudo(p.getOutputStream()); |
| } |
| }; |
| } |
| |
| protected void interactWithSudo(OutputStream os) throws Exception { |
| if (password != null) { |
| OutputStreamWriter osw = new OutputStreamWriter(os); |
| osw.write(password + "\n"); |
| osw.flush(); |
| } |
| os.close(); |
| } |
| |
| protected void copyFromSudo(String header, InputStream sudoStream) |
| throws Exception { |
| int b = '\n'; |
| while (true) { |
| if (b == '\n') |
| out.print(header); |
| b = sudoStream.read(); |
| if (b == -1) |
| break; |
| out.write(b); |
| out.flush(); |
| } |
| sudoStream.close(); |
| } |
| } |