The following assumes that you already have a built tree rooted in openxt.git with a completed build. It also assumes the build was done with with INHIBIT_RMWORK set. INHIBIT_RMWORK is set by default, and tells the build scripts to not delete the temporary packages build folders, so that we can go there, modify and rebuild source code.
The MACHINE variable
bitbake, the tool we use to build packages, uses the MACHINE environment variable to know what the current target (VM) is. A few possible values are xenclient-dom0 (to work on the main rootfs), xenclient-uivm (to work on the UI VM rootfs), xenclient-ndvm (to work on the network VM rootfs).
Make sure it is always set to something valid. Having "export MACHINE=xenclient-dom0" in your .bashrc is not a bad idea. If you are modifying multiple machines you can set it on the comment line before invoking the bb (which is a wrapper for the bitbake command).
The main folders
| Folder | Description |
|---|---|
openxt.git/build/ | The main work folder, where bb (bitbake wrapper) lives |
openxt.git/build/repos | Where all the OpenEmbedded repos get checked out |
openxt.git/build/repos/xenclient-oe/xenclient/recipes/ | The OpenXT-specific recipes (xenclient-oe.git) |
openxt.git/build/tmp-eglibc/ | The build folder, made not so "tmp" by INHIBIT_RMWORK |
openxt.git/build/tmp-eglibc/work/ | Where the building of the packages happen, each subfolder is an OE "machine" |
openxt.git/build/tmp-eglibc/work/core2-oe-linux/ | For non-machine-specific work, most of the non-kernel-related packages are built here |
The package folders
Those are located in openxt.git/build/oe/tmp-eglibc/work/*/[Package name]_[Package version]/ and can contain the following folders:
| Folder | Description |
|---|---|
[Package name]-[Package version]/ | The source code location for most non-git-based packages |
git/ | The source code location for git-based packages |
image/ | The build target folder, used to create the final packages |
temp/ | The build logs |
deploy_ipks/*/ | Where the final packages are |
Custom bibake rules
To run in openxt.git/build using ./bb -c [rule] [Package name]
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Note that the first 3 rules above are custom OpenXT rules to enable working in the build environment.
Example
Let's say trousers build failed because of a typo in the code, here's how to fix it (some of the steps here can usually be skipped, like the rebuild at the beginning):
$ cd openxt.git/build
$ ./bb -c cleansstate trousers && ./bb trousers # rebuild the package to make sure it's clean
$ less tmp-eglibc/work/core2-oe-linux/trousers-0.3.2-1-r2/temp/log.do_compile # figure out what failed
$ vi tmp-eglibc/work/core2-oe-linux/trousers-0.3.2-1-r2/trousers-0.3.2-1/src/tcs/tcs_caps.c # fix it
$ ./bb -c makeclean trousers # which does a -c force_rebuild
$ ./bb trousers
$ dpkg -c tmp-eglibc/work/core2-oe-linux/trousers-0.3.2-1-r2/deploy-ipks/core2/trousers_0.3.2-1-r2_core2.ipk # check the contents of the final packageThe case of dom0 Linux
Rebuilding Linux and updating a target is a bit more complicated and can break the target if not done properly.
Here's what to do after modifying the dom0 Linux code:
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