Changelog

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All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

2.0.0 - 2026-09-12

This release changes the default socket location and replaces filesystem-only connection isolation with explicit kernel peer-credential authorization. Review socket paths and allowed_uids before upgrading.

Added

  • Support UDS_DIST_DIR as a boot-time socket directory source.
  • Add allowed_uids application configuration and boot arguments. The policy defaults to the process's effective UID and accepts any or a list of trusted numeric UIDs.

Changed

  • Breaking: Replace the working-directory socket default with /tmp/uds-dist-<node-name>.sock. Path selection now follows application configuration, UDS_DIST_DIR, then the host-global fallback.
  • Breaking: Explicit filesystem socket directories now use mode 0755, and socket files use mode 0666. A missing directory leaf is created automatically; an existing leaf must be a real directory owned by the process's effective UID with mode 0755.
  • Breaking: Change the overlong-path exception from {socket_path_too_long, #{bytes => Bytes, max_bytes => Limit}} to {socket_path_too_long, Path, Limit}, and extend path-length validation to the supported BSD platforms.
  • Breaking: Require Linux, macOS, FreeBSD, NetBSD, OpenBSD, or DragonFly BSD so peer credentials can be enforced. Unsupported platforms fail at listener startup.
  • Retain the listener's resolved socket directory and UID policy until it closes, ensuring inbound and outbound connections use the same settings even if the environment changes.
  • Log the resolved socket path and accepted-peer UID policy when the listener starts.
  • Building from source now requires make and a C compiler for the small POSIX helper NIF, built through elixir_make.

Security

  • Authorize both inbound and outbound connections from kernel-supplied peer credentials before exchanging distribution-handshake data.
  • Fail closed when peer credentials or the POSIX helper are unavailable, reject Linux's overflowuid sentinel in explicit UID policies, and rate-limit rejected-connection logs.

Before a rolling upgrade from 1.0.x, configure every node with the new socket location; otherwise old and upgraded nodes will resolve different defaults and cannot connect. Change an existing mode-0700 configured socket directory to 0755. Cross-user release commands need an allowed UID policy and access to the daemon's distribution cookie.

1.0.1 - 2026-09-12

Changed

  • Publish tagged package versions to Hex.pm after the complete CI matrix passes.
  • Require Erlang/OTP 27 or newer, matching the Erlang syntax used by the library.
  • Report distribution socket statistics as packet counts, consistent with OTP's recv_cnt and send_cnt semantics.

Fixed

  • Recognise binary socket_dir values beginning with @ as Linux abstract namespace paths.
  • Return stale socket deletion errors instead of retrying indefinitely.
  • Close the accepted socket and distribution controller when the kernel rejects a protocol handshake.
  • Raise a descriptive error when a Unix socket path exceeds Linux or macOS address limits.

Security

  • Document filesystem directory permissions and the local-access implications of abstract namespace sockets.

1.0.0 - 2026-05-14

Added

  • Initial uds_dist module — custom Erlang distribution over Unix domain sockets using the :socket module, supporting both filesystem-backed and Linux abstract namespace sockets. Path selection is driven by the socket_dir application environment value, with a leading @ selecting the abstract namespace.