99-loginext.rules

# LogiNext — userspace access to the MX Master 3S event nodes and /dev/uinput.
#
# These rules let the daemon run unprivileged (the recommended workflow) by:
#
#   1. Granting the *currently logged-in seat user* an ACL on the matching
#      device nodes via systemd-logind's `uaccess` tag. This is the modern
#      replacement for blanket "input" group membership — access tracks the
#      active session, so a multi-user box doesn't leak input access.
#
#   2. Falling back to GROUP="input" + MODE="0660" so users on systems
#      without logind (or who explicitly opted into the `input` group) can
#      still open the devices. Both layers compose: uaccess wins when both
#      apply.
#
# Coverage:
#   - /dev/uinput  — required by `core/emitter.cpp` (synthetic mouse + kbd).
#   - MX Master 3S over Bolt receiver (046d:b034) — the supported pairing.
#   - MX Master 3S direct USB        (046d:c548) — for cabled use.
#
# To extend (Phase 3 — other Logitech mice):
#   - Add the pairing's USB ATTRS{idVendor}/idProduct in the `event*` line
#     pattern below. The TAG+="uaccess" tag is what makes the rule work
#     under logind; remove it only if you intentionally want input-group
#     gating instead.
#
# After editing, reload with:
#   sudo udevadm control --reload-rules
#   sudo udevadm trigger --subsystem-match=input --subsystem-match=misc
# (the package install runs both for you).

# ─── /dev/uinput ─────────────────────────────────────────────────────────
# `static_node=uinput` ensures the device node exists before the daemon
# tries to open it, even on kernels where `uinput` is a module that
# hasn't been autoloaded yet.
KERNEL=="uinput", SUBSYSTEM=="misc", \
    OPTIONS+="static_node=uinput", \
    TAG+="uaccess", GROUP="input", MODE="0660"

# ─── MX Master 3S — Bolt receiver (046d:b034) ────────────────────────────
KERNEL=="event*", SUBSYSTEMS=="usb", \
    ATTRS{idVendor}=="046d", ATTRS{idProduct}=="b034", \
    TAG+="uaccess", GROUP="input", MODE="0660"

# ─── MX Master 3S — direct USB cable (046d:c548) ─────────────────────────
KERNEL=="event*", SUBSYSTEMS=="usb", \
    ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c548", \
    TAG+="uaccess", GROUP="input", MODE="0660"