| /* |
| * 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. |
| */ |
| |
| package org.apache.tomcat.jni; |
| |
| import java.nio.ByteBuffer; |
| |
| /** Shm |
| * |
| * @author Mladen Turk |
| */ |
| public class Shm { |
| |
| /** |
| * Create and make accessible a shared memory segment. |
| * <br> |
| * A note about Anonymous vs. Named shared memory segments:<br> |
| * Not all platforms support anonymous shared memory segments, but in |
| * some cases it is preferred over other types of shared memory |
| * implementations. Passing a NULL 'file' parameter to this function |
| * will cause the subsystem to use anonymous shared memory segments. |
| * If such a system is not available, APR_ENOTIMPL is returned. |
| * <br> |
| * A note about allocation sizes:<br> |
| * On some platforms it is necessary to store some metainformation |
| * about the segment within the actual segment. In order to supply |
| * the caller with the requested size it may be necessary for the |
| * implementation to request a slightly greater segment length |
| * from the subsystem. In all cases, the apr_shm_baseaddr_get() |
| * function will return the first usable byte of memory. |
| * @param reqsize The desired size of the segment. |
| * @param filename The file to use for shared memory on platforms that |
| * require it. |
| * @param pool the pool from which to allocate the shared memory |
| * structure. |
| * @return The created shared memory structure. |
| * |
| */ |
| public static native long create(long reqsize, String filename, long pool) |
| throws Error; |
| |
| /** |
| * Remove shared memory segment associated with a filename. |
| * <br> |
| * This function is only supported on platforms which support |
| * name-based shared memory segments, and will return APR_ENOTIMPL on |
| * platforms without such support. |
| * @param filename The filename associated with shared-memory segment which |
| * needs to be removed |
| * @param pool The pool used for file operations |
| */ |
| public static native int remove(String filename, long pool); |
| |
| /** |
| * Destroy a shared memory segment and associated memory. |
| * @param m The shared memory segment structure to destroy. |
| */ |
| public static native int destroy(long m); |
| |
| /** |
| * Attach to a shared memory segment that was created |
| * by another process. |
| * @param filename The file used to create the original segment. |
| * (This MUST match the original filename.) |
| * @param pool the pool from which to allocate the shared memory |
| * structure for this process. |
| * @return The created shared memory structure. |
| */ |
| public static native long attach(String filename, long pool) |
| throws Error; |
| |
| /** |
| * Detach from a shared memory segment without destroying it. |
| * @param m The shared memory structure representing the segment |
| * to detach from. |
| */ |
| public static native int detach(long m); |
| |
| /** |
| * Retrieve the base address of the shared memory segment. |
| * NOTE: This address is only usable within the callers address |
| * space, since this API does not guarantee that other attaching |
| * processes will maintain the same address mapping. |
| * @param m The shared memory segment from which to retrieve |
| * the base address. |
| * @return address, aligned by APR_ALIGN_DEFAULT. |
| */ |
| public static native long baseaddr(long m); |
| |
| /** |
| * Retrieve the length of a shared memory segment in bytes. |
| * @param m The shared memory segment from which to retrieve |
| * the segment length. |
| */ |
| public static native long size(long m); |
| |
| /** |
| * Retrieve new ByteBuffer base address of the shared memory segment. |
| * NOTE: This address is only usable within the callers address |
| * space, since this API does not guarantee that other attaching |
| * processes will maintain the same address mapping. |
| * @param m The shared memory segment from which to retrieve |
| * the base address. |
| * @return address, aligned by APR_ALIGN_DEFAULT. |
| */ |
| public static native ByteBuffer buffer(long m); |
| |
| } |