c4e6d5c8be
This commit implements the core of the move to per-package SDK and target directories. The main idea is that instead of having a global output/host and output/target in which all packages install files, we switch to per-package host and target directories, that only contain their explicit dependencies. There are two main benefits: - Packages will now see only the dependencies they explicitly list in their <pkg>_DEPENDENCIES variable, and the recursive dependencies thereof. - We can support top-level parallel build properly, because a package only "sees" its own host directory and target directory, isolated from the build of other packages that can happen in parallel. It works as follows: - A new output/per-package/ directory is created, which will contain one sub-directory per package, and inside it, a "host" directory and a "target" directory: output/per-package/busybox/target output/per-package/busybox/host output/per-package/host-fakeroot/target output/per-package/host-fakeroot/host This output/per-package/ directory is PER_PACKAGE_DIR. - The global TARGET_DIR and HOST_DIR variable now automatically point to the per-package directory when PKG is defined. So whenever a package references $(HOST_DIR) or $(TARGET_DIR) in its build process, it effectively references the per-package host/target directories. Note that STAGING_DIR is a sub-dir of HOST_DIR, so it is handled as well. - Of course, packages have dependencies, so those dependencies must be installed in the per-package host and target directories. To do so, we simply rsync (using hard links to save space and time) the host and target directories of the direct dependencies of the package to the current package host and target directories. We only need to take care of direct dependencies (and not recursively all dependencies), because we accumulate into those per-package host and target directories the files installed by the dependencies. Note that this only works because we make the assumption that one package does *not* overwrite files installed by another package. This is done for "extract dependencies" at the beginning of the extract step, and for "normal dependencies" at the beginning of the configure step. This is basically enough to make per-package SDK and target work. The only gotcha is that at the end of the build, output/target and output/host are empty, which means that: - The filesystem image creation code cannot work. - We don't have a SDK to build code outside of Buildroot. In order to fix this, this commit extends the target-finalize step so that it starts by populating output/target and output/host by rsync-ing into them the target and host directories of all packages listed in the $(PACKAGES) variable. It is necessary to do this sequentially in the target-finalize step and not in each package. Doing it in package installation means that it can be done in parallel. In that case, there is a chance that two rsyncs are creating the same hardlink or directory at the same time, which makes one of them fail. This change to per-package directories has an impact on the RPATH built into the host binaries, as those RPATH now point to various per-package host directories, and no longer to the global host directory. We do not try to rewrite such RPATHs during the build as having such RPATHs is perfectly fine, but we still need to handle two fallouts from this change: - The check-host-rpath script, which verifies at the end of each package installation that it has the appropriate RPATH, is modified to understand that a RPATH to $(PER_PACKAGE_DIR)/<pkg>/host/lib is a correct RPAT. - The fix-rpath script, which mungles the RPATH mainly for the SDK preparation, is modified to rewrite the RPATH to not point to per-package directories. Indeed the patchelf --make-rpath-relative call only works if the RPATH points to the ROOTDIR passed as argument, and this ROOTDIR is the global host directory. Rewriting the RPATH to not point to per-package host directories prior to this is an easy solution to this issue. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Signed-off-by: Peter Korsgaard <peter@korsgaard.com> |
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| arch | ||
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| boot | ||
| configs | ||
| docs | ||
| fs | ||
| linux | ||
| package | ||
| support | ||
| system | ||
| toolchain | ||
| utils | ||
| .defconfig | ||
| .flake8 | ||
| .gitignore | ||
| .gitlab-ci.yml | ||
| .gitlab-ci.yml.in | ||
| CHANGES | ||
| Config.in | ||
| Config.in.legacy | ||
| COPYING | ||
| DEVELOPERS | ||
| Makefile | ||
| Makefile.legacy | ||
| README | ||
Buildroot is a simple, efficient and easy-to-use tool to generate embedded Linux systems through cross-compilation. The documentation can be found in docs/manual. You can generate a text document with 'make manual-text' and read output/docs/manual/manual.text. Online documentation can be found at http://buildroot.org/docs.html To build and use the buildroot stuff, do the following: 1) run 'make menuconfig' 2) select the target architecture and the packages you wish to compile 3) run 'make' 4) wait while it compiles 5) find the kernel, bootloader, root filesystem, etc. in output/images You do not need to be root to build or run buildroot. Have fun! Buildroot comes with a basic configuration for a number of boards. Run 'make list-defconfigs' to view the list of provided configurations. Please feed suggestions, bug reports, insults, and bribes back to the buildroot mailing list: buildroot@buildroot.org You can also find us on #buildroot on Freenode IRC. If you would like to contribute patches, please read https://buildroot.org/manual.html#submitting-patches