IPCEXCL

IPCEXCL is a conceptual mechanism used in inter-process communication to provide exclusion-based access control over IPC channels and messages. In a typical IPCEXCL model, each channel is governed by an exclusion policy that determines which processes may participate in communication, based on identity, capabilities, or tokens. The goal is to prevent unauthorized or unintended message exchanges while allowing legitimate interactions to proceed with low latency.

Implementation and operation: A policy engine evaluates incoming and outgoing messages against configured rules. Process identity, certificates, or capability tokens may be required for participation. Enforcement can be strict, blocking requests that fail policy checks, or permissive, emitting warnings or throttling instead of outright denial. Channel-level controls can be complemented by message-level filters to inspect payloads or metadata. In practice, IPCEXCL is usually layered atop existing IPC technologies by adding an access-control layer without replacing core primitives.

Applications and examples: IPCEXCL is discussed in theoretical works on secure IPC, multi-tenant and real-time systems, and in some experimental libraries that prototype access control for queues, topics, and shared memory. It is particularly suited to environments where separating tenants or processes with different security requirements is important, such as embedded systems or high-assurance software.

Limitations and considerations: Implementing IPCEXCL adds complexity and potential performance overhead. Careful policy design is required to avoid deadlocks, unfairness, or inadvertent denial of service. Compatibility with existing IPC semantics and debugging may be challenging, and terminology varies across implementations (IPCExcl, ExclusionIPC, etc.).

See also: Inter-process communication, Access control, Capability-based security, Message queues, Shared memory.