Daniel Samson
65244e3103
Programs can now subscribe to keyboard events (key_down/key_up/key_press) and drivers can broadcast them, through a new user-space input service. The delivery model is forced by danos IPC: a synchronous rendezvous holds one pending reply, so a server cannot park N subscribers blocked in a "wait for next event" call — delivery must be push. But a synchronous push has no timeout and the kernel never wakes a sender parked on a dead peer's endpoint, so one dying subscriber would hang all input. So this lands the roadmap's planned asynchronous buffered send and builds the service on it: - ipc_send (syscall 26): non-blocking post to an endpoint's bounded payload ring, delivered through reply_wait as a buffered message (notify_message_bit). A full ring drops the oldest. It can never hang on a dead/slow peer. - input-protocol + runtime.input helpers (subscribe/next, connectSource/ publish) — the first real consumer of M13 capability passing: a subscriber hands the service its own endpoint as a capability. - input service (fan-out via ipc_send, dead-subscriber pruning), a synthetic input-source, and input-test; the ps2-bus keyboard driver publishes to it. Real IRQ1 scancode decoding (which must live in the bus, the PNP0303 owner) is a documented follow-up; the source is synthetic for now. - build/init wiring, an `input` QEMU case, and docs/input.md. Full QEMU suite 48/48, including the new input case and every IPC/endpoint regression (ipc, ipc-call, ipc-cap, vfs, hpet, bus, irqfree).
DanOS
Codename: Shodan Version: 1
A small operating system, written from scratch in Zig — a bootloader (boot/)
and a microkernel (system/kernel/), sharing a neutral handoff contract (system/boot-handoff.zig).
It boots x86-64 via UEFI, and so far has a framebuffer console, a physical frame
allocator, its own paging with W^X permissions, interrupt/exception handling, a
LAPIC timer, a kernel heap, a fixed-priority preemptive scheduler, and in-kernel IPC
channels. See docs/ for how each piece works.
Prerequisites
- Zig 0.16.x — the build is pinned to this line (
.zig-version); other minor versions are rejected, because Zig makes breaking changes between releases pre-1.0. A toolchain manager such as zvm orzigupwill pick up.zig-versionautomatically. - QEMU (
qemu-system-x86_64) — to run and test the kernel. On macOS,brew install qemualso bundles the OVMF firmware below. - OVMF UEFI firmware — the
edk2-ovmfpackage (Arch),ovmf(Debian/Ubuntu), oredk2-ovmf(Fedora); on macOS it ships inside the Homebrewqemuformula. Both the build and the test harness probe the known Arch/Debian/Fedora/macOS layouts and use the first that exists, so no configuration is normally needed. Override with-Dovmf-code=/-Dovmf-vars=(build) if yours lives elsewhere. - Python 3 — for the QEMU integration test harness.
Build
zig build
Produces a FHS-shaped zig-out/ that is the danos filesystem and the boot volume:
the UEFI bootloader at zig-out/EFI/BOOT/BOOTX64.efi, the kernel at
zig-out/system/kernel, init at zig-out/system/services/init, drivers under
zig-out/system/drivers/, and the initial-ramdisk at zig-out/boot/.
Run
Boot it in QEMU with OVMF (opens a display window):
zig build run-x86-64
# distro with OVMF elsewhere:
zig build run-x86-64 -Dovmf-code=/path/OVMF_CODE.fd -Dovmf-vars=/path/OVMF_VARS.fd
Test
zig build test # host unit tests (the platform-independent shared code)
python3 test/qemu_test.py # QEMU integration tests: boots the kernel and asserts
# on its serial output (see docs/testing.md)
The integration harness builds and boots the kernel once per test case, checking memory, the frame allocator, paging (incl. NX and the null guard), the heap, interrupts, and exception handling. It exits non-zero on any failure, so it drops straight into CI.
Documentation
Design notes explaining the why behind the code live in
docs/ — start with docs/README.md.
Logo
San Serif Text "Dan OS" with a black karate belt around it.