lib-handoff

lib-handoff a thin, no-policy Rust crate for EriX handoff structures used in early boot and early userspace bootstrap.

EriX is a clean-room, capability-based microkernel operating system written entirely in Rust.

Technical requirements are tracked in the EriX requirements, conventions, and project documentation.

See:

• docs for design documents, specifications, and development plans.
• Related architecture repositories for kernel, services, libraries, drivers, and integration tooling.

Purpose of This Repository

This repository implements the EriX handoff library. Its purpose in EriX is to provide reusable handoff primitives and contracts to EriX components.

Functionally, it exposes the handoff APIs, validation tests, and documentation used by dependent repositories. The repository keeps the implementation, interface contracts, tests, and documentation for that behavior in one reviewable ownership boundary.

The maintained responsibilities are:

• expose the lib-handoff crate API for handoff behavior used by dependent components
• keep data formats, constants, and validation helpers documented and tested
• preserve clean-room, no-external-crate implementation boundaries
• maintain compatibility expectations for downstream repositories

Clean-Room Policy

EriX follows a strict clean-room philosophy:

• No external source code may be copied.
• No external Rust crates are allowed.
• No code generation tools that embed third-party code.
• All code must be authored within the project.

Violations will result in rejection of the contribution.

License

All EriX repositories are licensed under the ISC License.

Development Model

EriX development is modular, deterministic, reproducible, authority-explicit, security-first, and self-hosting oriented.

This repository follows the project roadmap and the validation rules documented in its own roadmap.

Testing strategy

• Positive fixture tests for valid v1 handoffs
• Negative tests for:
  • wrong magic/version
  • out-of-bounds offsets
  • integer overflow in table math
  • malformed entry size/count combinations
• Cross-repo compatibility tests (producer bytes match consumer decode)
• Determinism tests (same input bytes -> same parse result)

Dependencies

• External crates: none
• Internal dependencies: minimal; prefer no dependency where possible

See clean-room policy in ../docs/policies/no-external-code.md.

Status

Early development.

Protocol docs exist in docs/handoff; this crate is the implementation layer for those schemas. Current role constant set for root->services v1 is split as memd=1, vspaced=2, pagerd=3, procd=4 (>=1024 extension roles).

Governance Principles

lib-handoff governance is scoped to reusable handoff contracts shared by dependent repositories.

The scoped governance rules are:

• It must expose narrow, documented APIs rather than component-specific policy.
• It keeps wire formats, constants, parsers, and validation helpers deterministic and testable.
• It preserves clean-room implementation boundaries and does not introduce external crate dependencies.
• Breaking API or format changes require coordinated updates in every dependent repository.

Library Boundaries

• lib-handoff carries no runtime authority by itself; authority is held by callers that use the library.
• The crate must not hide ambient I/O, allocation policy, or service discovery behind helper APIs.

Contact

Development occurs in EriX organization and discussions happen in issues and design documents.

No decisions are considered valid without documented rationale.

Maintainers can be reached via email: admin@erikinkinen.fi.