Constructing the build directory

The Yocto Project's tool inputs and outputs were already detailed in a high abstract level in the previous chapters. We already know that BitBake uses metadata to generate a set of artifacts, including images. Besides the generated artifacts, BitBake creates much more content during the process, which may be used in several ways, dependent upon our goals.

During the build process, BitBake performs several tasks and modifies the build directory. We can understand it better following the usual BitBake flow, as follows:

• Fetching: The first action realized by BitBake is to download the source code. This step modifies the build directory, including a new tarball inside the build/download directory.
• Source preparation: After the fetching of the source code is complete, it must be prepared for use. This may involve, for example, the unpacking of a tarball or a clone of a local cached Git directory (from the download cache). The source code is prepared in the...