ksuinit: add build tool

.github/workflows/ksuinit.yml

@@ -26,11 +26,8 @@ jobs:
 
     - name: Build ksuinit
       run: |
-        LLVM_BIN=$ANDROID_NDK_HOME/toolchains/llvm/prebuilt/linux-x86_64/bin
-        export CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_LINKER="$LLVM_BIN/aarch64-linux-android26-clang"
-        export RUSTFLAGS="-C link-arg=-no-pie"
-        cd userspace/ksuinit
-        cargo build --target=aarch64-unknown-linux-musl --release
+        cd userspace
+        cargo build-ksuinit
 
     - name: Upload ksuinit artifact
       uses: actions/upload-artifact@v6

userspace/.cargo/config.toml

@@ -0,0 +1,2 @@
+[alias]
+build-ksuinit = "run --manifest-path tools/Cargo.toml --bin build-ksuinit --"

userspace/ksuinit/.cargo/config.example.toml

@@ -0,0 +1,3 @@
+[build]
+# uncomment below if you need rust-analyzer
+# target = "aarch64-unknown-linux-musl"

userspace/ksuinit/.gitignore

@@ -1,3 +1,3 @@
 /target
 /.idea
-.cargo
+.cargo/config.toml

userspace/tools/.gitignore

@@ -0,0 +1 @@
+target

userspace/tools/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "tools"
+version = "0.1.0"
+edition = "2024"
+
+[[bin]]
+name = "build-ksuinit"
+path = "src/bin/build-ksuinit.rs"
+
+[dependencies]

userspace/tools/src/bin/build-ksuinit.rs

@@ -0,0 +1,91 @@
+use std::env;
+use std::path::{Path, PathBuf};
+use std::process::{Command, ExitCode};
+
+const TARGET: &str = "aarch64-unknown-linux-musl";
+
+fn host_tag() -> &'static str {
+    match env::consts::OS {
+        "windows" => "windows",
+        "linux" => "linux",
+        "macos" => "darwin",
+        other => {
+            eprintln!("Unsupported host OS: {other}");
+            std::process::exit(2);
+        }
+    }
+}
+
+fn find_linker(ndk_home: &Path) -> PathBuf {
+    let base = ndk_home
+        .join("toolchains")
+        .join("llvm")
+        .join("prebuilt")
+        .join(format!("{}-x86_64", host_tag()))
+        .join("bin");
+
+    let linker = if cfg!(windows) {
+        let cmd = base.join("aarch64-linux-android26-clang.cmd");
+        if cmd.exists() {
+            cmd
+        } else {
+            base.join("aarch64-linux-android26-clang")
+        }
+    } else {
+        base.join("aarch64-linux-android26-clang")
+    };
+
+    if !linker.exists() {
+        eprintln!("Linker not found: {}", linker.display());
+        std::process::exit(2);
+    }
+
+    linker
+}
+
+fn main() -> ExitCode {
+    let ndk_home = match env::var("ANDROID_NDK_HOME") {
+        Ok(v) if !v.trim().is_empty() => v,
+        _ => {
+            eprintln!("ANDROID_NDK_HOME is required");
+            return ExitCode::from(2);
+        }
+    };
+
+    let linker = find_linker(Path::new(&ndk_home));
+    let rustflags = match env::var("RUSTFLAGS") {
+        Ok(existing) if !existing.trim().is_empty() => format!("{existing} -C link-arg=-no-pie"),
+        _ => "-C link-arg=-no-pie".to_string(),
+    };
+
+    let mut cmd = Command::new("cargo");
+    cmd.arg("build")
+        .arg("--target")
+        .arg(TARGET)
+        .arg("--release")
+        .current_dir(Path::new(env!("CARGO_MANIFEST_DIR")).join("../ksuinit"))
+        .env(
+            "CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_LINKER",
+            linker.as_os_str(),
+        )
+        .env("RUSTFLAGS", rustflags);
+
+    // Allow users to append extra build flags after `--`.
+    for arg in env::args().skip(1) {
+        cmd.arg(arg);
+    }
+
+    let status = match cmd.status() {
+        Ok(s) => s,
+        Err(e) => {
+            eprintln!("Failed to execute cargo build: {e}");
+            return ExitCode::from(1);
+        }
+    };
+
+    if status.success() {
+        ExitCode::SUCCESS
+    } else {
+        ExitCode::from(1)
+    }
+}