catalejo-sys

The system-level bindings to the mirilla kernel module.

Exception recovery uses one fd-owned context per process address space. Mapping the fd allocates a fixed-size read-write slab. Userspace fills a sorted prefix of 48-byte records and leaves the unused suffix zero. Changing the whole mapping to read-only publishes an immutable kernel snapshot. Changing it back to read-write removes that snapshot before editing resumes.

Mirilla implements the fd-backed mapping and publication lifecycle in a reusable slab subsystem. The exception consumer supplies owner-retention, snapshot-publication, and publication-revocation operations, while exception-specific validation and lookup remain outside the generic VMA code.

The Rust exception module exposes this lifecycle through Context and Slab. A slab tracks its current protection state and preserves ownership when a publication or edit transition fails. Catalejo's own linked fault routines use a PID-aware process Backend with one 12 KiB slab. A forked child receives stale descriptor state and must initialize a fresh backend before protected access.