Tomcat example source code file (Proc.java)

This example Tomcat source code file (Proc.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

apr_child_block, apr_just_wait, apr_kill_only_once, apr_kill_only_once, apr_no_pipe, apr_nowait, apr_oc_reason_running, apr_proc_exit, apr_program, apr_program_env, max_args_size, max_env_size, string, string

The Tomcat Proc.java source code

/*
 *  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;

/** Proc
 *
 * @author Mladen Turk
 * @version $Revision: 467222 $, $Date: 2006-10-24 05:17:11 +0200 (mar., 24 oct. 2006) $
 */

public class Proc {

    /*
     * apr_cmdtype_e enum
     */
    public static final int APR_SHELLCM      = 0; /** use the shell to invoke the program */
    public static final int APR_PROGRAM      = 1; /** invoke the program directly, no copied env */
    public static final int APR_PROGRAM_ENV  = 2; /** invoke the program, replicating our environment */
    public static final int APR_PROGRAM_PATH = 3; /** find program on PATH, use our environment */
    public static final int APR_SHELLCMD_ENV = 4; /** use the shell to invoke the program,
                                                   *   replicating our environment
                                                   */

    /*
     * apr_wait_how_e enum
     */
    public static final int APR_WAIT   = 0; /** wait for the specified process to finish */
    public static final int APR_NOWAIT = 1; /** do not wait -- just see if it has finished */

    /*
     * apr_exit_why_e enum
     */
    public static final int APR_PROC_EXIT        = 1; /** process exited normally */
    public static final int APR_PROC_SIGNAL      = 2; /** process exited due to a signal */
    public static final int APR_PROC_SIGNAL_CORE = 4; /** process exited and dumped a core file */

    public static final int APR_NO_PIPE       = 0;
    public static final int APR_FULL_BLOCK    = 1;
    public static final int APR_FULL_NONBLOCK = 2;
    public static final int APR_PARENT_BLOCK  = 3;
    public static final int APR_CHILD_BLOCK   = 4;

    public static final int APR_LIMIT_CPU     = 0;
    public static final int APR_LIMIT_MEM     = 1;
    public static final int APR_LIMIT_NPROC   = 2;
    public static final int APR_LIMIT_NOFILE  = 3;


    /** child has died, caller must call unregister still */
    public static final int APR_OC_REASON_DEATH      = 0;
    /** write_fd is unwritable */
    public static final int APR_OC_REASON_UNWRITABLE = 1;
    /** a restart is occuring, perform any necessary cleanup (including
     * sending a special signal to child)
     */
    public static final int APR_OC_REASON_RESTART    = 2;
    /** unregister has been called, do whatever is necessary (including
     * kill the child)
     */
    public static final int APR_OC_REASON_UNREGISTER = 3;
    /** somehow the child exited without us knowing ... buggy os? */
    public static final int APR_OC_REASON_LOST       = 4;
    /** a health check is occuring, for most maintainence functions
     * this is a no-op.
     */
    public static final int APR_OC_REASON_RUNNING    = 5;

    /* apr_kill_conditions_e enumeration */
    /** process is never sent any signals */
    public static final int APR_KILL_NEVER         = 0;
    /** process is sent SIGKILL on apr_pool_t cleanup */
    public static final int APR_KILL_ALWAYS        = 1;
    /** SIGTERM, wait 3 seconds, SIGKILL */
    public static final int APR_KILL_AFTER_TIMEOUT = 2;
    /** wait forever for the process to complete */
    public static final int APR_JUST_WAIT          = 3;
    /** send SIGTERM and then wait */
    public static final int APR_KILL_ONLY_ONCE     = 4;

    public static final int APR_PROC_DETACH_FOREGROUND = 0; /** Do not detach */
    public static final int APR_PROC_DETACH_DAEMONIZE  = 1; /** Detach */

    /* Maximum number of arguments for create process call */
    public static final int MAX_ARGS_SIZE          = 1024;
    /* Maximum number of environment variables for create process call */
    public static final int MAX_ENV_SIZE           = 1024;

    /**
     * Allocate apr_proc_t stucture from pool
     * This is not an apr function.
     * @param cont The pool to use.
     */
    public static native long alloc(long cont);

    /**
     * This is currently the only non-portable call in APR.  This executes
     * a standard unix fork.
     * @param proc The resulting process handle.
     * @param cont The pool to use.
     * @return APR_INCHILD for the child, and APR_INPARENT for the parent
     * or an error.
     */
    public static native int fork(long [] proc, long cont);

    /**
     * Create a new process and execute a new program within that process.
     * This function returns without waiting for the new process to terminate;
     * use apr_proc_wait for that.
     * @param progname The program to run
     * @param args The arguments to pass to the new program.  The first
     *             one should be the program name.
     * @param env The new environment table for the new process.  This
     *            should be a list of NULL-terminated strings. This argument
     *            is ignored for APR_PROGRAM_ENV, APR_PROGRAM_PATH, and
     *            APR_SHELLCMD_ENV types of commands.
     * @param attr The procattr we should use to determine how to create the new
     * process
     * @param pool The pool to use.
     * @return The resulting process handle.
     */
    public static native int create(long proc, String progname,
                                    String [] args, String [] env,
                                    long attr, long pool);

    /**
     * Wait for a child process to die
     * @param proc The process handle that corresponds to the desired child process
     * @param exit exit[0] The returned exit status of the child, if a child process
     *                dies, or the signal that caused the child to die.
     *                On platforms that don't support obtaining this information,
     *                the status parameter will be returned as APR_ENOTIMPL.
     * exit[1] Why the child died, the bitwise or of:
     * <PRE>
     * APR_PROC_EXIT         -- process terminated normally
     * APR_PROC_SIGNAL       -- process was killed by a signal
     * APR_PROC_SIGNAL_CORE  -- process was killed by a signal, and
     *                          generated a core dump.
     * </PRE>
     * @param waithow How should we wait.  One of:
     * <PRE>
     * APR_WAIT   -- block until the child process dies.
     * APR_NOWAIT -- return immediately regardless of if the
     *               child is dead or not.
     * </PRE>
     * @return The childs status is in the return code to this process.  It is one of:
     * <PRE>
     * APR_CHILD_DONE     -- child is no longer running.
     * APR_CHILD_NOTDONE  -- child is still running.
     * </PRE>
     */
    public static native int wait(long proc, int [] exit, int waithow);

    /**
     * Wait for any current child process to die and return information
     * about that child.
     * @param proc Pointer to NULL on entry, will be filled out with child's
     *             information
     * @param exit exit[0] The returned exit status of the child, if a child process
     *                dies, or the signal that caused the child to die.
     *                On platforms that don't support obtaining this information,
     *                the status parameter will be returned as APR_ENOTIMPL.
     * exit[1] Why the child died, the bitwise or of:
     * <PRE>
     * APR_PROC_EXIT         -- process terminated normally
     * APR_PROC_SIGNAL       -- process was killed by a signal
     * APR_PROC_SIGNAL_CORE  -- process was killed by a signal, and
     *                          generated a core dump.
     * </PRE>
     * @param waithow How should we wait.  One of:
     * <PRE>
     * APR_WAIT   -- block until the child process dies.
     * APR_NOWAIT -- return immediately regardless of if the
     *               child is dead or not.
     * </PRE>
     * @param pool Pool to allocate child information out of.
     */
    public static native int waitAllProcs(long proc, int [] exit,
                                          int waithow, long pool);

     /**
     * Detach the process from the controlling terminal.
     * @param daemonize set to non-zero if the process should daemonize
     *                  and become a background process, else it will
     *                  stay in the foreground.
     */
    public static native int detach(int daemonize);

    /**
     * Terminate a process.
     * @param proc The process to terminate.
     * @param sig How to kill the process.
     */
    public static native int kill(long proc, int sig);

}