Toolkit: Fix readdirent toolchain errors for reusable chroots

[dmcilvaney]

Merge Checklist

All boxes should be checked before merging the PR (just tick any boxes which don't apply to this PR)

• The toolchain has been rebuilt successfully (or no changes were made to it)
• The toolchain/worker package manifests are up-to-date
• Any updated packages successfully build (or no packages were changed)
• Packages depending on static components modified in this PR (Golang, *-static subpackages, etc.) have had their Release tag incremented.
• Package tests (%check section) have been verified with RUN_CHECK=y for existing SPEC files, or added to new SPEC files
• All package sources are available
• cgmanifest files are up-to-date and sorted (./cgmanifest.json, ./toolkit/scripts/toolchain/cgmanifest.json, .github/workflows/cgmanifest.json)
• LICENSE-MAP files are up-to-date (./LICENSES-AND-NOTICES/SPECS/data/licenses.json, ./LICENSES-AND-NOTICES/SPECS/LICENSES-MAP.md, ./LICENSES-AND-NOTICES/SPECS/LICENSE-EXCEPTIONS.PHOTON)
• All source files have up-to-date hashes in the *.signatures.json files
• sudo make go-tidy-all and sudo make go-test-coverage pass
• Documentation has been updated to match any changes to the build system
• Ready to merge

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Summary

When using the Docker compatible reusable chroots (CHROOT_DIR=...), a number of mount points need to be established external to the toolkit. One set is ./build/toolchain_rpms{x86_64,aarch64,noarch}:chroot-1/toolchainrpms/{x86_64,aarch64,noarch} (and similar for other chroots).

As part of #9899 and #9963 the $(STATUS_FLAGS_DIR)/toolchain_auto_cleanup.flag was added which removes all toolchain rpms from the repo folder ./build/toolchain_rpms (to remove the chance of unexpected conflicts with signatures or validation state). It simply removed the outer ./build/toolchain_rpms directory, breaking the mountpoints in the docker environment.

Oddly, as the build runs, it re-creates the toolchain folder, and the mount points contained in it reappear, but are broken.

The pkgworker tool has a function removeLibArchivesFromSystem() which walks the entirety of the chroot's filesystem looking for *.la files and removing them. The broken mount points are sufficiently "real" that filepath.Walk() will detect them and try to recursively walk them, but then hits readdirent /toolchainrpms/aarch64: no such file or directory (this is not unique to aarch64, it occurs on all three mounts).

We can resolve this by preserving the directory structure of the toolchain folder when running the sanitization step, so the mounts will remain intact.

Change Log

• Use find ... -exec rm ... in $(STATUS_FLAGS_DIR)/toolchain_auto_cleanup.flag instead of a simple rm to avoid breaking docker chroot mounts.

Does this affect the toolchain?

NO

Associated issues

• https://microsoft.visualstudio.com/OS/_workitems/edit/53339865/?triage=true

Test Methodology

• Locally reproduced version of the pipeline VMs which use Docker + reusable chroots, running build commands manually.