synexec
-------
 Synchronised Executioner

 Copyright 2014 (c) Citrix

 Disclaimer:
  This program 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, version only.

  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 General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.


 Description:
  Synchronised Executioner is a VERY INSECURE, UNAUTHENTICATED network-based
  cooperative protocol developed to coordinate the execution of tasks, possibly
  in a virtualised environment. A master process (ideally running on a control
  domain) and one or more slave processes (ideally running within virtual
  machines) will cooperate to:

  - Establish a session amongst the master and the slaves;
  - Negotiate what tasks are to be executed and transfer the necessary data;
  - Execute the tasks, keeping track of progress and reporting periodically.

  See NOTES for further information on the protocol.


 WARNING:
  Remember that this software will allow ANY MASTER (including any other
  software, malicious or not, that understands the protocol) to run ANY CODE
  on a reachable host running a synexec_slave. 


 Compiling:
  Run "make" from the project root directory.


 Usage:
  To run a master process:
  ./synexec_master [ -hvd ] [ -i <if_name> ]
                   [ -p <port> ] [-s <session> ] <slaves> <conf>

  -h             Print a help message and quit.
  -v             Increase verbosity (may be used multiple times).
  -d             Run as daemon. stdout/stderr will be redirect to a log file.
  -i <if_name>   Use interface <if_name> instead of default.
  -p <port>      Override default network port (5165) with <port>.
  -s <session>   Define session ID to <session> (uint32_t, default 0).
  <slaves>       Wait for these many slaves before starting.
  <conf>         Configuration file for this session.

  A configuration file is organised as follows:

  First line:
   * The command line to be executed by the slaves.
   * The first parameter of this command line must be an executable file.
   * First line example: /bin/sleep 5s

  Remainder of the file:
   * The remainder of the file will be copied to the slave.
   * By default, a slave will store the file in /tmp/synexec_slave_conf.<pid>
   * The configuration file can be passed in the command line by using the
     special tag ":CONF:" (without quotes).

  Full example:
   /bin/bash :CONF:
   #!/bin/bash
   mkdir /src || exit
   /bin/dd if=/dev/urandom of=/src/file.dat bs=1024 count=1048576
   cp -a /src /dst

  Explanation:
   The above configuration file will result into a file being created into
   each slave's /tmp/ and named synexec_slave_conf.1234 (where 1234 is the
   corresponding PID for the synexec_slave process. The file contents will
   be:
 
   #!/bin/bash
   mkdir /src || exit
   /bin/dd if=/dev/urandom of=/src/file.dat bs=1024 count=1048576

   The slave will then execute the following command:
   /bin/bash /tmp/synexec_slave_conf.1234

   All the output from the slave will be placed into the file synexec.out,
   also in the /tmp/ directory.