Module doebuild

Create and store environment variable in the config instance that's passed in as the "settings" parameter. This will raise UnsupportedAPIException if the given ebuild has an unsupported EAPI. All EAPI dependent code comes last, so that essential variables like PORTAGE_BUILDDIR are still initialized even in cases when UnsupportedAPIException needs to be raised, which can be useful when uninstalling a package that has corrupt EAPI metadata. The myroot and use_cache parameters are unused.

Wrapper function that invokes specific ebuild phases through the spawning
of ebuild.sh

@param myebuild: name of the ebuild to invoke the phase on (CPV)
@type myebuild: String
@param mydo: Phase to run
@type mydo: String
@param _unused: Deprecated (use settings["ROOT"] instead)
@type _unused: String
@param settings: Portage Configuration
@type settings: instance of portage.config
@param debug: Turns on various debug information (eg, debug for spawn)
@type debug: Boolean
@param listonly: Used to wrap fetch(); passed such that fetch only lists files required.
@type listonly: Boolean
@param fetchonly: Used to wrap fetch(); passed such that files are only fetched (no other actions)
@type fetchonly: Boolean
@param cleanup: Passed to prepare_build_dirs (TODO: what does it do?)
@type cleanup: Boolean
@param dbkey: A file path where metadata generated by the 'depend' phase
        will be written.
@type dbkey: String
@param use_cache: Enables the cache
@type use_cache: Boolean
@param fetchall: Used to wrap fetch(), fetches all URIs (even ones invalid due to USE conditionals)
@type fetchall: Boolean
@param tree: Which tree to use ('vartree','porttree','bintree', etc..), defaults to 'porttree'
@type tree: String
@param mydbapi: a dbapi instance to pass to various functions; this should be a portdbapi instance.
@type mydbapi: portdbapi instance
@param vartree: A instance of vartree; used for aux_get calls, defaults to db[myroot]['vartree']
@type vartree: vartree instance
@param prev_mtimes: A dict of { filename:mtime } keys used by merge() to do config_protection
@type prev_mtimes: dictionary
@param fd_pipes: A dict of mapping for pipes, { '0': stdin, '1': stdout }
        for example.
@type fd_pipes: Dictionary
@param returnpid: Return a list of process IDs for a successful spawn, or
        an integer value if spawn is unsuccessful. NOTE: This requires the
        caller clean up all returned PIDs.
@type returnpid: Boolean
@rtype: Boolean
@return:
1. 0 for success
2. 1 for error

Most errors have an accompanying error message.

listonly and fetchonly are only really necessary for operations involving 'fetch'
prev_mtimes are only necessary for merge operations.
Other variables may not be strictly required, many have defaults that are set inside of doebuild.

Spawn a subprocess with extra portage-specific options.
Optiosn include:

Sandbox: Sandbox means the spawned process will be limited in its ability t
read and write files (normally this means it is restricted to ${D}/)
SElinux Sandbox: Enables sandboxing on SElinux
Reduced Privileges: Drops privilages such that the process runs as portage:portage
instead of as root.

Notes: os.system cannot be used because it messes with signal handling.  Instead we
use the portage.process spawn* family of functions.

This function waits for the process to terminate.

@param mystring: Command to run
@type mystring: String
@param mysettings: Either a Dict of Key,Value pairs or an instance of portage.config
@type mysettings: Dictionary or config instance
@param debug: Ignored
@type debug: Boolean
@param free: Enable sandboxing for this process
@type free: Boolean
@param droppriv: Drop to portage:portage when running this command
@type droppriv: Boolean
@param sesandbox: Enable SELinux Sandboxing (toggles a context switch)
@type sesandbox: Boolean
@param fakeroot: Run this command with faked root privileges
@type fakeroot: Boolean
@param keywords: Extra options encoded as a dict, to be passed to spawn
@type keywords: Dictionary
@rtype: Integer
@return:
1. The return code of the spawned process.