# node-addon-landlock-run

A [Landlock](https://landlock.io/) self-restrict-then-exec launcher for confining subprocesses on Linux, distributed as prebuilt per-platform npm packages plus a thin JS entry package that resolves the binary and speaks its CLI contract. Built for agent harnesses and other hosts that need to run untrusted commands under a filesystem allow-list without confining themselves.

The first tool is **`landlock-run`** — a self-restrict-then-exec [Landlock](https://landlock.io/) launcher (~300 lines of C11 over the raw kernel UAPI, statically linked against musl). It installs a Landlock ruleset on itself and `exec`s the wrapped command; the ruleset is inherited across `execve`, so the command and every process it spawns run confined while the invoking process stays unrestricted. Fail-closed: if the kernel cannot enforce, it exits without running the command.

## Install

```sh
npm install node-addon-landlock-run
```

Published packages use an entry package plus platform optional packages:

```text
node-addon-landlock-run
node-addon-landlock-run-linux-x64
node-addon-landlock-run-linux-arm64
```

npm's `os`/`cpu` fields make installers fetch only the matching platform package. There is no install-time build fallback on purpose: on a host without a platform package the resolved path never exists, the probe reports `unusable`, and the consumer falls closed.

## Usage

```js
import { grantArgs, launcherPath, probe } from 'node-addon-landlock-run';

const launcher = launcherPath();
if (probe(launcher) !== 'unusable') {
  const argv = [launcher, ...grantArgs({ readOnly: ['/'], readWrite: ['/tmp/work'] }), '--', 'bash', '-c', command];
  // spawn argv with your process runner of choice
}
```

The public API is intentionally small:

- `launcherPath()`: absolute path of this host's launcher (existence deliberately unchecked — the probe is the availability signal).
- `probe(launcher?, { timeoutMs? })`: functional enforcement probe — `'full' | 'partial' | 'unusable'`.
- `grantArgs({ readOnly?, readWrite? })`: the launcher's grant argv; everything not granted is denied.
- `LAUNCHER_BIN`, `LAUNCHER_FAILURE_EXIT` (125): contract constants.

The full binary contract (argv grammar, exit codes, report lines) is pinned in [docs/cli-contract.md](docs/cli-contract.md).

## Support

linux-x64 and linux-arm64, kernel with Landlock enabled (5.13+; ABI level determines `full` vs `partial` enforcement — see [docs/support-matrix.md](docs/support-matrix.md)). Other platforms deliberately have no package: consumers run different confinement backends there.

## Development

```sh
corepack enable
pnpm install
pnpm build:ts        # entry packages → lib/
pnpm build:native    # this Linux architecture's binaries (apt-get install musl-tools)
pnpm test
```

Binaries are git-ignored and built natively per architecture — locally for your own machine, by CI's per-arch runners as the builders of record. Release flow: [docs/release.md](docs/release.md).
