AOS licensing
This document is the repository's authoritative map of license scopes. A file's SPDX identifier or an explicit license notice in its component takes precedence over the defaults below. Third-party files retain their existing licenses.
#License map
| Scope | License |
|---|---|
| Original AOS code without a more specific notice | Apache-2.0 |
crucible-protocol and crucible-shmem | MIT OR Apache-2.0 |
crucible-qemu-plugin | GPL-2.0-only |
crucible-debug-gateway | GPL-2.0-only |
crucible-qemu-trace-plugin | GPL-2.0-only |
| QEMU emulator as a combined work | GPL-2.0-only |
| Individual QEMU source files | The file's notice; unmarked files default to GPL-2.0-or-later under QEMU 11.1's LICENSE |
| AOS QEMU patch series | Modified files retain their upstream license; every created file and its license is listed in the patch inventory |
The complete license texts are in LICENSES/. The root
LICENSE remains the Apache License 2.0 default for original
AOS code and allows GitHub to identify that default accurately. The repository
and AOS distributions are multi-license aggregates: the presence of
Apache-licensed code does not relicense QEMU, and this project does not claim
that all bundled software is Apache-2.0.
#Crucible/QEMU process boundary
The Apache-licensed Crucible host and QEMU are separate processes. They communicate through a public, versioned protocol: a Unix-domain socket is the setup and control plane, and shared memory is the high-throughput data plane. The protocol is an interoperability contract, not a shared implementation.
crucible-protocol and crucible-shmem contain protocol and transport
definitions used on both sides of that process boundary. Their permissive
MIT OR Apache-2.0 license lets independently licensed peers implement the same
contract. This does not change the license of either peer.
crucible-qemu-plugin is loaded into QEMU and calls QEMU plugin interfaces. It
is therefore part of the GPL side of the boundary and is licensed
GPL-2.0-only. Its dependency on the dual-licensed boundary crates is taken
under their MIT option, which is compatible with GPL-2.0-only. Any other code
compiled into, linked into, or
dynamically loaded by QEMU must remain within the applicable QEMU/GPL license
scope. Apache-only host crates must not link to QEMU or include QEMU headers.
QEMU's combined-work license and its per-file licenses are separate metadata:
the current patch series creates GPL-2.0-or-later QEMU source files, while the
Rust and C Crucible QEMU plugins remain explicitly GPL-2.0-only. Packages and
corresponding-source artifacts must preserve and inventory both GPL scopes.
crucible-debug-gateway is a GPL-2.0-only standalone process. It owns the
persistent debugger session and connects to QEMU's private RSP socket. The
Apache controller communicates with it only through versioned Unix-socket
frames defined by the dual-licensed crucible-protocol crate; neither process
links or dynamically loads the other.
Shared memory must remain protocol-shaped. It may contain fixed-width fields, atomics, offsets, ring entries, sequence numbers, feature bits, and serialized payloads specified by the public ABI. It must not contain native pointers, function or callback tables, QEMU private structures, Rust-native layouts, or other process-private objects. See the normative licensing and process boundary.
#Distribution and corresponding source
AOS intends the controller, QEMU/plugin backend, and convenience suite to be packaged as distinguishable components aggregated for installation. The legal characterization of a particular distribution depends on the facts of that distribution; in all cases, each component's applicable license and notices must be honored. Package and release descriptions must list the licenses they contain and must not describe a bundle containing QEMU as wholly Apache-2.0.
Anyone distributing a modified QEMU binary must satisfy the applicable GPL and
upstream obligations. An AOS release or public binary cache that offers the
Crucible QEMU binary must offer the complete corresponding source from an
equally accessible location. That source artifact must include the exact QEMU
source, the complete applied patch series, new QEMU/plugin integration source,
generated interface files required to build it, build/configuration scripts,
license notices, and enough identity metadata to match it to the binary. Release
automation must fail closed if the artifact or license inventory is missing.
qemu-crucible is therefore an internal, non-standalone release component:
apr publish and apr release --store-path reject its store path directly.
They inspect the complete runtime closure, so publishing the plugin or an
unmarked wrapper around patched QEMU is rejected as well. Publish the
crucible suite root instead. Its indexed release policy directly retains
both qemu-crucible and the matching qemu-crucible-source path, so both are
members of the binary-cache closure without making source a QEMU runtime
dependency. Generic, unpatched QEMU packages have no such restriction.
This repository document describes project policy and is not legal advice.
#Contributions
Contributions follow the license applicable to the files changed. External AOS
contributors require the external contributor license agreement. Current Andyl,
Inc. employees contributing within the scope of their employment are covered by
Andyl's standard CIAA and internal contribution authorization instead. Commits
to QEMU, its patch series, or in-QEMU code additionally require a Developer
Certificate of Origin Signed-off-by line for both contribution paths. See
CONTRIBUTING.md and the
External Contributor License Agreement.