2.8.5.1. Source Fetching

-2.8.5.1. Source Fetching

- The first stages of building a recipe are to fetch and unpack - the source code: -

- The - do_fetch - and - do_unpack - tasks fetch the source files and unpack them into the work - directory. -

Note

- For every local file (e.g. file://) - that is part of a recipe's - SRC_URI - statement, the OpenEmbedded build system takes a checksum - of the file for the recipe and inserts the checksum into - the signature for the do_fetch. - If any local file has been modified, the - do_fetch task and all tasks that - depend on it are re-executed. -

- By default, everything is accomplished in the - Build Directory, - which has a defined structure. - For additional general information on the Build Directory, - see the - "build/" - section in the Yocto Project Reference Manual. -

- Unpacked source files are pointed to by the - S - variable. - Each recipe has an area in the Build Directory where the - unpacked source code resides. - The name of that directory for any given recipe is defined from - several different variables. - You can see the variables that define these directories - by looking at the figure: -

TMPDIR - - The base directory where the OpenEmbedded build system - performs all its work during the build. -
PACKAGE_ARCH - - The architecture of the built package or packages. -
TARGET_OS - - The operating system of the target device. -
PN - - The name of the built package. -
PV - - The version of the recipe used to build the package. -
PR - - The revision of the recipe used to build the package. -
WORKDIR - - The location within TMPDIR where - a specific package is built. -
S - - Contains the unpacked source files for a given recipe. -