# cloud9 integration

The published `cloud9` package owns the base 9P2000 wire format, client and server
connections, and TCP/Unix/QUIC transports. `build.zig.zon` pins a commit from
`git@git.sr.ht:~gbrls/cloud9`, so `zig build` fetches it into `zig-pkg/` like every
other dependency; no sibling checkout is required. Re-pin with
`zig fetch --save=cloud9 git+https://git.sr.ht/~gbrls/cloud9#<commit>`, and swap in
`.cloud9 = .{ .path = "../cloud9" }` while editing both packages at once.

The file-server engine (fids, jobs, parking, flush, hangup) is cloud9's
`fs.Server`; the control tree in `src/ninep/` is its backend, using cloud9's
`fs.Req`, `fs.Op`, `fs.Status`, `fs.E` and `fs.ReplyWith` (extended with the
editor's reply payload locator). `src/9p.zig` names the editor's and the
board's `fs.Options` and re-exports the wire names the transports use.
Mounting, Unix namespace discovery and permissions, the editor event loop,
connection limits, and exported tree policy remain here. `src/9p_quic.zig`
selects the existing `pardes-9p` ALPN for cloud9's optional OpenSSL transport.
The standalone protocol/GPIO tests import the same module. The separate
`05-zig-p4` build also supplies cloud9 for the GPIO firmware entry.

Run `zig build 9p-test` for the engine configurations and
`zig build 9p-io-test -Dquic=true` for native transport/client integration. Run cloud9's `zig build test`,
`transport-test`, `quic-test -Dquic=true`, `fuzz`, and `differential` steps for the
shared implementation. See cloud9's `docs/validation.md` for recorded runs and
known test-environment limits.

Invalid framing now terminates a server connection. Cloud9 also checks reply
counts and reserves tags until flush completion. Client metadata is slightly
larger to track those reservations, and its bounds tests reflect that fixed cost.