lib-vfs

lib-vfs is the no_std typed client and path-validation crate for the public EriX filesystem interface.

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 VFS library. Its purpose in EriX is to provide reusable VFS primitives and contracts to EriX components.

Functionally, it exposes the VFS 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-vfs crate API for VFS 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.

Status

Implemented baseline for the public VFS client contract:

• canonical path and name validation
• bounded UTF-8 path/name validation through lib-fs-name
• no public unchecked constructor for canonical directory-entry names
• typed transport helpers for all current public VFS ops
• dedicated flagged open/create encoding and compact flag-free encoding for mkdir, stat, readlink, unlink, and rmdir
• additive helpers for rename, truncate, symlink, readlink, link, and flagged metadata updates
• generic mount_fs(path, fs_type, block_device_id, flags) helper, with volatile-memory providers mounted through mount_fs
• FAT12, FAT16, and exFAT provider kind constants without changing the mount request layout
• fixed-size inline read/write payload handling, including a direct-into read helper that avoids returning a second transport-sized payload
• error mapping for transport, framing, and service result-code failures
• unit coverage for path rejection plus open/create/read/write/readdir/stat and extended-operation roundtrips

Validation

• cargo fmt
• cargo clippy --all-targets --all-features -- -D warnings
• cargo test --all-targets --all-features

Governance Principles

lib-vfs governance is scoped to reusable VFS 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-vfs 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.