Bitbake Shell Wrapper Script

Script to create a 'clean' shell environment for Bitbake builds to occur.
The intent is to prevent contamination of the host shell environment AND to prevent contamination of the build shell.

• direct execution mode: bbsh < options > -- < command > < command options >
  Ex: bbsh -d -b ../ -- bitbake-layers --help
• shell creation mode : bbsh < options >
  Ex: bbsh -d -b ../

Configuration files tailor the defaults of this script.
Files will be searched and sourced in the following order:

• Location of the script file itself, e.g. ~/bin/bbsh.conf
• Current working directory, e.g. ./bbsh.conf
• Build directory, if it exists, e.g. ${BUILD_DIR}/bbsh.conf
• Command line specified configuration file.

DEBUG, INIT_ARGS, INIT_SETUP_SCRIPT, PREPEND_PATHS, SETUP_SCRIPT

1. Currently, configuration parsing is rudimentary and only works for single line entries.

bbsh < options > -- < command > < command options >  
    -b|--build <build dir>   build execution directory, defaults to ./  
    -c|--config <file>       add a configuration file to use  
    -d|--debug               enable debug output  
    -h|--help  
    -i|--init                initial invocation will create the build directory  
      |--init-args           arguments to pass during the initial invocation  
      |--init-setup--script  script to call for the initial invocation  
    -l|--layer <layer dir>   meta-data layers directory, defaults to <build>/../  
    -p|--paths <paths>       paths, delimited by ':', to prepend to \$PATH  
                               e.g.  --paths \"a:b:c\"  
    -s|--script <file>       setup script to run before execution  
                               defaults to <layer directory>/oe-init-build-env  
    -u|--user-conf-only      only use the conf file specified with -c  

• Shells can be nested and will be indicated by the prompt
• Options that specify files assume relative paths to the calling directory for this script.
• Command line options should override anything in a configuration file
• Renaming the script will change the default configuration files searched

1. Explore using chroot/schroot to provide more isolation to the build environment.
2. Make more shell agnostic and remove bash-isms
3. Add color to output

Copyright (c) 2017 Sean Hudson

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.