# LaunchManager.java

    /*
    ** Module   : LaunchManager.java
    ** Abstract : External application launcher.
    **
    ** Copyright (c) 2010-2023, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- ---------------------------------Description----------------------------------
    ** 001 SIY 20100629 Created initial version
    ** 002 SIY 20100804 Changes in imports, some refactorings.
    ** 003 SIY 20100817 Moved to util package.
    ** 004 LMR 20101123 Made process launching/waiting routines
    **                  (pseudoTerminalLaunch(), pseudoTerminalWait())
    **                  native, using libp2j.so, thus decoupling them
    **                  from charva and libTerminal.so.
    ** 005 GES 20111006 Cleaned up an import, added a helper method and added
    **                  docs.
    ** 006 EVL 20140117 The native library call is performing now in dedicated place and only once.
    **                  See the ClientCore class. Removed init native call due to this is signal
    **                  related.
    ** 007 ECF 20150126 Added background mode flag to pseudoTerminalLaunch signature.
    ** 008 EVL 20160224 Javadoc fixes to make compatible with Oracle Java 8 for Solaris 10.
    ** 009 GBB 20231207 Adding FWD_VERSION env var before launching a new child process.
    */
    /*
    ** This program is free software: you can redistribute it and/or modify
    ** it under the terms of the GNU Affero General Public License as
    ** published by the Free Software Foundation, either version 3 of the
    ** License, or (at your option) any later version.
    **
    ** This program 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 Affero General Public License for more details.
    **
    ** You may find a copy of the GNU Affero GPL version 3 at the following
    ** location: https://www.gnu.org/licenses/agpl-3.0.en.html
    **
    ** Additional terms under GNU Affero GPL version 3 section 7:
    **
    **   Under Section 7 of the GNU Affero GPL version 3, the following additional
    **   terms apply to the works covered under the License.  These additional terms
    **   are non-permissive additional terms allowed under Section 7 of the GNU
    **   Affero GPL version 3 and may not be removed by you.
    **
    **   0. Attribution Requirement.
    **
    **     You must preserve all legal notices or author attributions in the covered
    **     work or Appropriate Legal Notices displayed by works containing the covered
    **     work.  You may not remove from the covered work any author or developer
    **     credit already included within the covered work.
    **
    **   1. No License To Use Trademarks.
    **
    **     This license does not grant any license or rights to use the trademarks
    **     Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
    **     of Golden Code Development Corporation. You are not authorized to use the
    **     name Golden Code, FWD, or the names of any author or contributor, for
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    **
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    **
    **     You may not represent yourself as Golden Code Development Corporation or FWD.
    **
    **     You may not represent yourself for publicity purposes as associated with
    **     Golden Code Development Corporation, FWD, or any author or contributor to
    **     the covered work, without written authorization.
    **
    **   3. No Misrepresentation of Source or Origin.
    **
    **     You may not represent the covered work as solely your work.  All modified
    **     versions of the covered work must be marked in a reasonable way to make it
    **     clear that the modified work is not originating from Golden Code Development
    **     Corporation or FWD.  All modified versions must contain the notices of
    **     attribution required in this license.
    */

    package com.goldencode.p2j.util;

    import java.io.*;

    /**
     * External program launch manager which properly handles terminal state
     * during program execution.
     */
    public class LaunchManager
    {
       /**
        * Creates a child process with all or some of its stdio handles redirected
        * to the pipes and the rest of them left unchanged. Unchanged stdio handles
        * are inherited from the calling process and normally are connected to the
        * process' terminal.
        * <p>
        * The handles redirected to the pipes can be used to communicate between
        * processes.
        * <p>
        * In Progress, there are following use cases for the redirected I/O:
        * <table style="text-align: left; width: 100%;" border="1" cellspacing="2"
        *  cellpadding="2" summary="">
        *   <tbody>
        *     <tr>
        *       <td style="vertical-align: top;">stdio\\use<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;
        *           font-weight: bold;">Interactive Process Launch<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;
        *           font-weight: bold;">INPUT THROUGH<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;
        *           font-weight: bold;">INPUT-OUTPUT THROUGH<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;"><span
        *           style="font-weight: bold;">OUTPUT THROUGH</span><br>
        *       </td>
        *     </tr>
        *     <tr>
        *       <td style="vertical-align: top;">stdin<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;">TTY<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;">TTY<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;">pipe<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;">pipe<br>
        *       </td>
        *     </tr>
        *     <tr>
        *       <td style="vertical-align: top;">stdout<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;">TTY<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;">pipe<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;">pipe<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;">TTY<br>
        *       </td>
        *     </tr>
        *     <tr>
        *       <td style="vertical-align: top;">stderr<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;">TTY<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;">pipe<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;">pipe<br>
        *       </td>
        *       <td style="vertical-align: top; text-align: center;">TTY<br>
        *       </td>
        *     </tr>
        *   </tbody>
        * </table>
        *
        * @param    cmdline
        *           The command line to execute.  The first element must be the
        *           program name.
        * @param    in
        *           File descriptor to be associated with the pipe that redirects
        *           stdin, or <code>null</code> if no redirection is required.
        * @param    out
        *           File descriptor to be associated with the pipe that redirects
        *           stdout, or <code>null</code> if no redirection is required.
        * @param    err
        *           File descriptor to be associated with the pipe that redirects
        *           stderr, or <code>null</code> if no redirection is required.
        * @param    silent
        *           <code>false</code> for interactive mode (there the terminal
        *           is expected to be shared by the child process and the user is
        *           allowed to directly interact with the child process.
        * @param    background
        *           <code>true</code> if client is running in the background
        *           (disconnected from its controlling terminal); else <code>false</code>.
        * @param    fwdVersion
        *           The FWD version.
        *
        * @return   The ID of the launched child process.
        */
       public static native int pseudoTerminalLaunch(String[]       cmdline,
                                                     FileDescriptor in,
                                                     FileDescriptor out,
                                                     FileDescriptor err,
                                                     boolean        silent,
                                                     boolean        background,
                                                     String         fwdVersion);

       /**
        * Wait for a specific child process (which was previously launched
        * using {@link #pseudoTerminalLaunch}) to exit.
        *
        * @param    pid
        *           ID of the child process to be waited.
        * @param    silent
        *           <code>false</code> for interactive mode (there the terminal
        *           is expected to be shared by the child process and the user is
        *           allowed to directly interact with the child process.
        */
       public static native void pseudoTerminalWait(int pid, boolean silent);

       /**
        * Wait for a specific non-interactive child process (which was previously
        * launched using {@link #pseudoTerminalLaunch}) to exit.
        *
        * @param    pid
        *           ID of the child process to be waited.
        */
       public static void pseudoTerminalWait(int pid)
       {
          pseudoTerminalWait(pid, true);
       }
    }