Daniel Samson
afbf10f7fc
Add a `system_spawn(name)` system call: the kernel loads a binary bundled in the initial-ramdisk, by name, as a fresh ring-3 process. It's the mechanism a user-space supervisor needs — discovery and policy stay in user space, the kernel only spawns. The kernel already holds the initial-ramdisk image from the boot handoff; it now stashes it (process.setInitialRamdisk) so the handler can resolve names, bounds-checks the name into the user half like debug_write, and returns -1 for an unknown name or a load failure. Ungated for now (any process may spawn any bundled binary); a spawn capability belongs here once the model grows one. The device manager stops logging "would spawn it" and calls runtime.system.spawn on its matched driver. On QEMU it discovers the HPET, matches `hpet`, and spawns it — and the driver comes all the way up (claims the timer, maps its MMIO, binds and services its IRQ, prints "hpet: ok"). The device-manager test now keys on that final marker: since only the manager is spawned, `hpet: ok` appearing proves the whole discover -> match -> system_spawn -> driver-up chain end to end. Transitional: the kernel still auto-spawns the whole initial-ramdisk at boot, so a real boot briefly double-spawns hpet (the second claim fails harmlessly). Increment 3 removes that redundancy so the manager is the sole owner of driver spawning. Suite 36/36 plus host tests.
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.