qemu: Enable user_static builds for providing user mode emulation.

[Sumynwa]

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

---

Summary

This PR introduces changes to enable user_static builds in qemu to build qemu-user-static* arch specific packages for providing user mode emulation. This enables support to run for ex aarch64 bins using qemu-user-static-aarch64 sub-package via binfmt-misc on x86_64 host. By default, the binfmt config is set with 'F = fix binary' flag to preload the interpreter binary to allow running non-native instructions inside the container environment.

The sub-package qemu-user-binfmt also provides binfmt config but they are dynamic interpreter configurations.
For ex qemu-aarch64, the interpreter registered is "/usr/bin/qemu-aarch64" which is a dynamically linked shared object.
Also, the interpreter is registered without the F = fix binary flag.
We cannot use this package for container-based builds because:

• there are no entries inside the /proc/sys/fs/binfmt_misc IN the containers mount ns
• when installing arm64 packages, the pre/post scriptlets start to fail when trying to run without the 'F' flag
  • because there is no binfmt_misc registered inside container ns
  • in host, the interpreter is not loaded since without F indicates lazy loading by kernel
  • tries to execute arm64 instructions natively and fails

Change Log

• Enable user_static global compile flag
• configure user_static with 'enable_pie'
• manage systemd-binfmt restarts post install/uninstall to avoid start-limit-hit
• add conflicts between qemu-user-static and qemu-user-binfmt as both
  provide binfmt rules

Does this affect the toolchain?

NO

Associated issues

• #xxxx

Links to CVEs

• https://nvd.nist.gov/vuln/detail/CVE-YYYY-XXXX

Test Methodology

• Pipeline build id: Buddy Build

[harshitgupta1337]

Looks good to me. Just a nit comment.

[kgodara912]

Buddy build after recent changes.

[kgodara912]

As such changes look fine, just a minor clarification needed.

[kgodara912]

The parent directory may not be available in some scenarios, for example in containers, should we try to create the directory first, mkdir -p to avoid file exists, and then touch the file so that file creation doesn't fail or we are not going to support containers altogether as PR description says?

[Sumynwa]

Yes, we should create it just in case.
This works in vm install since it is already created by initramfs.
I will make changes.

[Sumynwa]

Changes done.