Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

Since bitbake switched back to the fork instead of the exec model,
it no longer used bitbake-runtask and the code has suffered some bitrot.
bitbake-runtask is a useful tool for excuting the task without
the scheduler of bitbake, so that the external tool can invoke it
easily. It also provides a useful example of how to invoke exec_task()
with low overhead without a lot of the bitbake threading/UI overhead.

Significant changes:

* This patch changes the argument order so that the commonly used
  and mandatory arguments come first.

* The taskhash file and dryrun options are now optional

* It now uses the bitbake logging mechanisms to provide processed
  logging output to the console.

* The process handling to do with stdout/stderr redirection
  are removed since they're no longer required.

[YOCTO #1229]

RP: Logging updates to the patch based on Roberts original patch
Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/bitbake-runtask: Since the parent has set the environment up cleanly we don't need to filter this ourselves anymore

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

Currently, anything whitelisted in the environment makes it into the worker
processes. This is undesireable and the worker environment should be as
clean as possible. This patch adapts bitbake sosme variables are loaded into
bitbake's datastore but not exported by default. Any variable can be exported
by setting its export flag.

Currently, this code only finalises the environment in he worker as doing so
in the server means variables are unavailable in the worker. If we switch
back to fork() calls instead of exec() this code will need revisting.

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

bitbake-runtask: Ensure logging settings take effect in the worker process (and pass verbose setting)

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

[BUGID #291]

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

bitbake/bitbake-runtask: Signatures are needed in task context and have little overhead so enable in worker context

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

Pass task has informaiton to work processes, allowing full manipulation of
the hash data in the task context allowing checksums to be usable.

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

bitbake/build.py: Set BB_FILENAME to represent the .bb file being built (including any virtual prefix)

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

bitbake: Switch to use subprocess for forking tasks and FAKEROOTENV to run shell and python under a fakeroot environment

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>