Struct KqueueEventsSource 

pub struct KqueueEventsSource {
    pub config: KqueueEventsConfig,
}

Harvests timing jitter from kqueue event notification multiplexing.

What it measures

Nanosecond timing of kevent() calls with multiple registered event types (timers, file watchers, socket monitors) firing concurrently.

Why it’s entropic

kqueue is the macOS/BSD kernel event notification system. Registering diverse event types simultaneously creates rich interference:

• Timer events — EVFILT_TIMER with different intervals fire at kernel-determined times affected by timer coalescing, interrupt handling, and power management state
• File watchers — EVFILT_VNODE on temp files monitors inode changes; traverses VFS, APFS/HFS event queues, and the kqueue knote hash table
• Socket events — EVFILT_READ/EVFILT_WRITE on socket pairs monitors buffer state; interacts with the network stack’s mbuf allocator
• Knote lock contention — many registered watchers all compete for the kqueue’s internal knote lock and dispatch queue

What makes it unique

No prior work has combined multiple kqueue event types as an entropy source. The cross-event-type interference (timer delivery affecting socket notification timing) produces entropy that is independent from any single event source.

Configuration

See KqueueEventsConfig for tunable parameters. Key options:

• num_timers: controls timer coalescing interference
• num_sockets: controls mbuf allocator contention
• num_file_watchers: controls VFS notification path diversity
• timeout_ms: controls kevent() wait duration

Fields

config: KqueueEventsConfig

Source configuration. Use Default::default() for recommended settings.

Trait Implementations

impl Default for KqueueEventsSource

fn default() -> KqueueEventsSource

Returns the “default value” for a type.

impl EntropySource for KqueueEventsSource

fn info(&self) -> &SourceInfo

Source metadata.

fn is_available(&self) -> bool

Check if this source can operate on the current machine.

fn collect(&self, _n_samples: usize) -> Vec<u8>

Collect raw entropy samples. Returns a Vec<u8> of up to n_samples bytes.

fn name(&self) -> &'static str

Convenience: name from info.