/projects/haiku-9p

A 9P2000.L filesystem client implementation for Haiku OS. Enables mounting Plan 9/QEMU shared folders directly in Haiku, bridging the gap between Haiku and host systems during development.

What is 9P?

9P is a network protocol for distributed file systems originally developed for Plan 9 from Bell Labs. The 9P2000.L variant extends it with Linux-specific features for better POSIX compatibility. QEMU uses 9P for virtfs host folder sharing.

# Start QEMU with shared folder

qemu-system-x86_64 \

-virtfs local,path=/shared,mount_tag=host,security_model=mapped-xattr

# Mount in Haiku

mount -t 9p -o tag=host /mnt/host

Protocol Implementation

Core Operations

Tversion/Rversion - Protocol negotiation
Tattach/Rattach - Filesystem attach
Twalk/Rwalk - Path traversal
Tlopen/Rlopen - File open
Tread/Rread - Read data
Twrite/Rwrite - Write data
Tclunk/Rclunk - Release handle

9P2000.L Extensions

Tgetattr/Rgetattr - POSIX stat
Tsetattr/Rsetattr - chmod/chown
Treaddir/Rreaddir - Directory listing
Tmkdir/Rmkdir - Create directory
Tunlinkat/Runlinkat - Delete file
Tsymlink/Rsymlink - Create symlink
Tstatfs/Rstatfs - Filesystem stats

Progress Tracker

Done

Protocol message encoding
Message decoding/parsing
Basic client library
Test infrastructure

In Progress

Kernel module integration
VFS layer binding
Virtio transport

Planned

Mount command support
Caching layer
Performance tuning

Use Cases

Development: Share code between host and Haiku VM without network setup
Testing: Easily transfer test files and results
Building: Access build tools and outputs across systems
Integration: Enable CI/CD pipelines with shared artifacts