nexus

Nexus is a set of Linux kernel modules that bridge the Linux kernel with the BeOS/Haiku userspace runtime. It is a core component of VitruvianOS, included as a submodule.

Overview

BeOS and Haiku expose kernel APIs with no direct equivalent in Linux — IPC ports, named semaphores, shared memory areas, a thread messaging model, and filesystem event notifications. Nexus implements these as thin kernel modules on top of the standard Linux kernel, exposing them to userspace through character devices and ioctl interfaces.

Modules

nexus (/dev/nexus)

Main IPC module. Implements the BeOS/Haiku kernel primitives used by the messaging subsystem:

• Ports — bounded message queues identified by integer ID or name; supports blocking read/write with timeouts
• Threads — per-thread send/receive channels with spawn, resume, waitfor, and exit lifecycle operations
• Semaphores — counting semaphores with acquire/release and timeout support
• Areas — named shared memory regions with protection control and cross-team transfer

Each process that opens /dev/nexus gets its own nexus_team context. Teams and threads are tracked in kernel memory and cleaned up automatically on release.

node_monitor

Filesystem event notifications implementing the BeOS node_monitor API on top of Linux's fsnotify subsystem. Translates kernel filesystem events into BeOS-compatible messages delivered to registered userspace listeners:

• B_ENTRY_CREATED / B_ENTRY_REMOVED / B_ENTRY_MOVED
• B_STAT_CHANGED / B_ATTR_CHANGED
• B_DEVICE_MOUNTED / B_DEVICE_UNMOUNTED

Repository structure

nexus/          kernel module source (area.c, nexus.c, vref.c, node_monitor.c, ...)
debian/         packaging for nexus-dkms Debian package
nexus.conf      modules-load.d config (loads nexus + nexus_vref at boot)
CMakeLists.txt  integration with the VitruvianOS build system

Distribution

Nexus is distributed as nexus-dkms, a DKMS Debian package that compiles and installs the modules against the target kernel on the live image. It is built automatically as part of the VitruvianOS .deb and ISO build pipeline.

Building

As part of VitruvianOS

Nexus is built automatically. See the VitruvianOS build instructions.

Standalone

Requires kernel headers for the running kernel:

make -C /lib/modules/$(uname -r)/build M=$(pwd)/nexus modules

Load manually:

sudo insmod nexus/nexus.ko
sudo insmod nexus/nexus_vref.ko

Or install and load via DKMS/modules-load:

sudo cp nexus.conf /etc/modules-load.d/

License

GPL-2.0. Copyright (C) 2022–2026 Dario Casalinuovo.