ISSUE-683: Add ARM support for GitHub Actions

.github/workflows/test.yml

@@ -15,7 +15,9 @@ jobs:
     name: Test Suite
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        # ubuntu-24.04-arm is the GitHub-hosted arm64 Linux runner;
+        # macos-latest already runs on Apple Silicon (arm64).
+        os: [ubuntu-latest, ubuntu-24.04-arm, macos-latest, windows-latest]
         rust: [stable]
     runs-on: ${{ matrix.os }}
 

README.md

@@ -56,11 +56,13 @@ Arch:
 |         <!--Installation Guide-->          |          <!--Documentation-->          |       <!--Discord-->        |
 | :----------------------------------------: | :------------------------------------: | :-------------------------: |
 | :book: [Installation Guide][toc-install] | :books: [Documentation][links-table-2] | :parrot: [Discord][discord] |
+|                                          | :penguin: [ARM Support](docs/arm-support.md) |                           |
 
 ## 🙋 Table of Contents
 
 - 📖 [Installation Guide][toc-install]
 - 🐋 [Docker Usage][toc-docker-usage]
+- 🐧 [ARM Support](docs/arm-support.md)
 - 🦜 [Discord][discord]
 - 🤸 [Usage][usage-1]
 

docs/arm-support.md

@@ -0,0 +1,38 @@
+# ARM support
+
+This page covers which ARM targets RustScan's CI builds and tests, and how to build ARM binaries yourself.
+
+## What CI covers
+
+| Target | Built by | Tested by |
+| --- | --- | --- |
+| `aarch64-unknown-linux-gnu` (64-bit ARM Linux) | `build-nix` job in [build.yml](../.github/workflows/build.yml) | `Test Suite (ubuntu-24.04-arm)` in [test.yml](../.github/workflows/test.yml) |
+| `armv7-unknown-linux-gnueabihf` (32-bit ARM Linux) | `build-nix` job in [build.yml](../.github/workflows/build.yml) | not tested in CI |
+| `aarch64-apple-darwin` (Apple Silicon macOS) | `build-macos-aarch64` job in [build.yml](../.github/workflows/build.yml) | `Test Suite (macos-latest)` in [test.yml](../.github/workflows/test.yml) |
+
+- **Builds** use [`houseabsolute/actions-rust-cross`](https://github.com/houseabsolute/actions-rust-cross). It cross-compiles the Linux ARM targets with [`cross`](https://github.com/cross-rs/cross) on x86_64 runners.
+- **Tests** run natively on GitHub-hosted arm64 runners: `ubuntu-24.04-arm` for Linux, and `macos-latest`, which runs on Apple Silicon. They run the same `just test` recipe as every other platform.
+
+## Building ARM binaries locally
+
+The simplest option is `cross`, which runs the build in a container that already has the right toolchain and linker. It needs Docker or Podman.
+
+```sh
+cargo install cross
+cross build --locked --release --target aarch64-unknown-linux-gnu
+# or, for 32-bit ARM:
+cross build --locked --release --target armv7-unknown-linux-gnueabihf
+```
+
+The binary ends up at `target/<target>/release/rustscan`.
+
+On an ARM machine (for example a Raspberry Pi running a 64-bit OS, or an Apple Silicon Mac) you don't need `cross`; a normal native build works:
+
+```sh
+cargo build --locked --release
+```
+
+## Troubleshooting
+
+- **`error[E0463]: can't find crate for std`, or linker errors:** you're cross-compiling with plain `cargo`. Either use `cross`, or install the target (`rustup target add <target>`) along with a matching cross linker.
+- **`cross` can't pull its image:** check that Docker or Podman is running and that your user can reach it.