From f2f70d6ba2b3a4d24b0794c980efeb13cb9d80a7 Mon Sep 17 00:00:00 2001 From: Casey Marshall Date: Wed, 23 Apr 2003 22:49:53 +0000 Subject: Moved from java/security/Engine.java --- gnu/java/security/Engine.java | 237 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 237 insertions(+) create mode 100644 gnu/java/security/Engine.java diff --git a/gnu/java/security/Engine.java b/gnu/java/security/Engine.java new file mode 100644 index 000000000..9f6568cdd --- /dev/null +++ b/gnu/java/security/Engine.java @@ -0,0 +1,237 @@ +/* Engine -- generic getInstance method. + Copyright (C) 2003 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., 59 Temple Place, Suite 330, Boston, MA +02111-1307 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 gnu.java.security; + +import java.lang.reflect.Constructor; +import java.lang.reflect.InvocationTargetException; + +import java.security.NoSuchAlgorithmException; +import java.security.Provider; + +/** + * Generic implementation of the getInstance methods in the various + * engine classes in java.security. + *

+ * These classes ({@link java.security.Signature} for example) can be + * thought of as the "chrome, upholstery, and steering wheel", and the SPI + * (service provider interface, e.g. {@link java.security.SignatureSpi}) + * classes can be thought of as the "engine" -- providing the actual + * functionality of whatever cryptographic algorithm the instance + * represents. + * + * @see Provider + * @author Casey Marshall + */ +public final class Engine +{ + + // Constants. + // ------------------------------------------------------------------------ + + /** Prefix for aliases. */ + private static final String ALG_ALIAS = "Alg.Alias."; + + /** Maximum number of aliases to try. */ + private static final int MAX_ALIASES = 5; + + /** Argument list for no-argument constructors. */ + private static final Object[] NO_ARGS = new Object[0]; + + // Constructor. + // ------------------------------------------------------------------------ + + /** This class cannot be instantiated. */ + private Engine() { } + + // Class method. + // ------------------------------------------------------------------------ + + /** + * Get the implementation for algorithm for service + * service from provider. The service is e.g. + * "Signature", and the algorithm "DSA". + * + * @param service The service name. + * @param algorithm The name of the algorithm to get. + * @param provider The provider to get the implementation from. + * @return The engine class for the specified algorithm; the object + * returned is typically a subclass of the SPI class for that + * service, but callers should check that this is so. + * @throws NoSuchAlgorithmException If the implementation cannot be + * found or cannot be instantiated. + * @throws InvocationTargetException If the SPI class's constructor + * throws an exception. + * @throws IllegalArgumentException If any of the three arguments are null. + */ + public static Object getInstance(String service, String algorithm, + Provider provider) + throws InvocationTargetException, NoSuchAlgorithmException + { + return getInstance(service, algorithm, provider, NO_ARGS); + } + + /** + * Get the implementation for algorithm for service + * service from provider, passing initArgs to the + * SPI class's constructor (which cannot be null; pass a zero-length + * array if the SPI takes no arguments). The service is e.g. + * "Signature", and the algorithm "DSA". + * + * @param service The service name. + * @param algorithm The name of the algorithm to get. + * @param provider The provider to get the implementation from. + * @param initArgs The arguments to pass to the SPI class's + * constructor (cannot be null). + * @return The engine class for the specified algorithm; the object + * returned is typically a subclass of the SPI class for that + * service, but callers should check that this is so. + * @throws NoSuchAlgorithmException If the implementation cannot be + * found or cannot be instantiated. + * @throws InvocationTargetException If the SPI class's constructor + * throws an exception. + * @throws IllegalArgumentException If any of the four arguments are null. + */ + public static Object getInstance(String service, String algorithm, + Provider provider, Object[] initArgs) + throws InvocationTargetException, NoSuchAlgorithmException + { + if (service == null || algorithm == null + || provider == null || initArgs == null) + throw new IllegalArgumentException(); + + // If there is no property "service.algorithm" + if (provider.getProperty(service + "." + algorithm) == null) + { + // Iterate through aliases, until we find the class name or resolve + // too many aliases. + String alias = null; + int count = 0; + while ((alias = provider.getProperty( + ALG_ALIAS + service + "." + algorithm)) != null) + { + if (algorithm.equals(alias)) // Refers to itself! + break; + algorithm = alias; + if (count++ > MAX_ALIASES) + throw new NoSuchAlgorithmException("too many aliases"); + } + if (provider.getProperty(service + "." + algorithm) == null) + throw new NoSuchAlgorithmException(algorithm); + } + + // Find and instantiate the implementation. + Class clazz = null; + ClassLoader loader = provider.getClass().getClassLoader(); + Constructor constructor = null; + String error = algorithm; + + try + { + if (loader != null) + clazz = loader.loadClass(provider.getProperty(service+"."+algorithm)); + else + clazz = Class.forName(provider.getProperty(service+"."+algorithm)); + constructor = getCompatibleConstructor(clazz, initArgs); + return constructor.newInstance(initArgs); + } + catch (ClassNotFoundException cnfe) + { + error = "class not found: " + algorithm; + } + catch (IllegalAccessException iae) + { + error = "illegal access: " + iae.getMessage(); + } + catch (InstantiationException ie) + { + error = "instantiation exception: " + ie.getMessage(); + } + catch (ExceptionInInitializerError eiie) + { + error = "exception in initializer: " + eiie.getMessage(); + } + catch (SecurityException se) + { + error = "security exception: " + se.getMessage(); + } + catch (NoSuchMethodException nsme) + { + error = "no appropriate constructor found"; + } + + throw new NoSuchAlgorithmException(error); + } + + // Own methods. + // ------------------------------------------------------------------------ + + /** + * Find a constructor in the given class that can take the specified + * argument list, allowing any of which to be null. + * + * @param clazz The class from which to get the constructor. + * @param initArgs The argument list to be passed to the constructor. + * @return The constructor. + * @throws NoSuchMethodException If no constructor of the given class + * can take the specified argument array. + */ + private static Constructor getCompatibleConstructor(Class clazz, + Object[] initArgs) + throws NoSuchMethodException + { + Constructor[] c = clazz.getConstructors(); + outer:for (int i = 0; i < c.length; i++) + { + Class[] argTypes = c[i].getParameterTypes(); + if (argTypes.length != initArgs.length) + continue; + for (int j = 0; j < argTypes.length; j++) + { + if (initArgs[j] != null && + !argTypes[j].isAssignableFrom(initArgs[j].getClass())) + continue outer; + } + // If we reach this point, we know this constructor (c[i]) has + // the same number of parameters as the target parameter list, + // and all our parameters are either (1) null, or (2) assignable + // to the target parameter type. + return c[i]; + } + throw new NoSuchMethodException(); + } +} -- cgit v1.2.1