zerodds-rt-linux

Layer 4 — Core Services. Linux real-time scheduling adapter.

zerodds-rt-linux is the only crate in the workspace with an unsafe FFI boundary (COMFORT class). It provides SCHED_FIFO/SCHED_RR/SCHED_DEADLINE profiles + CPU pinning via sched_setattr(2) and sched_setaffinity(2).

Spec anchors

  • sched(7) Linux man page.
  • sched_setattr(2), sched_getattr(2).
  • sched_setaffinity(2), sched_getaffinity(2).

No OMG spec — Linux kernel API.

Layer position

Layer 4. No ZeroDDS crate deps; libc is the only external dep, target-gated cfg(target_os = "linux"). On non-Linux all public APIs return io::ErrorKind::Unsupported.

Quickstart

use zerodds_rt_linux::{SchedulerProfile, pin_current_thread_to_cpus};

let profile = SchedulerProfile::fifo(80).expect("priority valid");
profile.apply_to_current_thread().expect("CAP_SYS_NICE required");
pin_current_thread_to_cpus(&[2, 3]).expect("affinity set");

Privileges

SCHED_FIFO/SCHED_RR with priority > 0 + SCHED_DEADLINE need CAP_SYS_NICE (effective). Without it, calls abort with EPERM.

Threat model + 5 invariants

  1. No pointer outliving — stack-local structures, no heap.
  2. No FD leak — none of the syscalls used create FDs.
  3. No memory aliasing — buffers are exclusive during the call.
  4. Errno-to-Result — io::Error::last_os_error() once before any further libc operations.
  5. No mut-aliasing race — all calls refer to tid = 0 (the calling thread).

Every unsafe { libc::... } block carries a // SAFETY: comment.

Stability

1.0.0-rc.3. Public API + errno mapping RC1-stable. sched_setattr(2) has been a Linux-kernel-stable API since kernel 3.14.

zerodds-rt-linux

Layer 4 — Core Services. Linux Real-Time-Scheduling Adapter.

zerodds-rt-linux ist die einzige Crate im Workspace mit unsafe-FFI-Boundary (COMFORT-Klasse). Liefert SCHED_FIFO/SCHED_RR/SCHED_DEADLINE-Profile + CPU-Pinning ueber sched_setattr(2) und sched_setaffinity(2).

Spec-Anker

  • sched(7) Linux-Manpage.
  • sched_setattr(2), sched_getattr(2).
  • sched_setaffinity(2), sched_getaffinity(2).

Keine OMG-Spec — Linux-Kernel-API.

Schichten-Position

Layer 4. Keine ZeroDDS-Crate-Deps; libc ist die einzige externe Dep, target-gegated cfg(target_os = "linux"). Auf Nicht-Linux liefern alle Public-APIs io::ErrorKind::Unsupported.

Quickstart

use zerodds_rt_linux::{SchedulerProfile, pin_current_thread_to_cpus};

let profile = SchedulerProfile::fifo(80).expect("priority valid");
profile.apply_to_current_thread().expect("CAP_SYS_NICE noetig");
pin_current_thread_to_cpus(&[2, 3]).expect("affinity set");

Privilegien

SCHED_FIFO/SCHED_RR mit Priority > 0 + SCHED_DEADLINE brauchen CAP_SYS_NICE (effective). Ohne brechen Calls mit EPERM ab.

Threat-Model + 5 Invarianten

  1. Kein Pointer-Outliving — Stack-lokale Strukturen, kein Heap.
  2. Kein FD-Leak — keiner der genutzten Syscalls erzeugt FDs.
  3. Kein Memory-Aliasing — Buffer sind exklusiv waehrend des Aufrufs.
  4. Errno-zu-Result — io::Error::last_os_error() einmal vor weiteren libc-Operationen.
  5. Keine Mut-Aliasing-Race — alle Calls beziehen sich auf tid = 0 (calling thread).

Jeder unsafe { libc::... }-Block traegt einen // SAFETY:-Kommentar.

Stabilitaet

1.0.0-rc.3. Public-API + Errno-Mapping RC1-stabil. sched_setattr(2) ist Linux-Kernel-stabile-API seit Kernel 3.14.