Merge #195

195: Check for kernel manifest r=mkroening a=mkroening

Closes #194.

The essence of this PR is adding `--manifest-path Cargo.toml` to the kernel compilation command. Without it, Cargo searches for the Cargo.toml file in the current directory or any parent directory. That results in cargo compiling this repository with the kernel triple, causing #194.

This does a little refactoring around the kernel triple, adds `--manifest-path Cargo.toml` and adds a manual check for the existence of the kernel manifest. I also added a note to the README for checking out submodules as requested by `@tlambertz.`

Co-authored-by: Martin Kröning <mkroening@posteo.net>

Author: bors[bot]

README.md

@@ -49,6 +49,8 @@ rustup component add rust-src
 rustup component add llvm-tools-preview
 ```
 
+If you work with this repository, remember to checkout the submodules.
+
 ## Building your own applications
 
 To give you an example on how to build your application with RustyHermit, lets create a new cargo project:

hermit-sys/build.rs

@@ -11,14 +11,32 @@ use std::process::Command;
 use walkdir::{DirEntry, WalkDir};
 
 fn build_hermit(src_dir: &Path, target_dir_opt: Option<&Path>) {
+	let manifest_path = src_dir.join("Cargo.toml");
 	assert!(
-		src_dir.exists(),
-		"rusty_hermit source folder does not exist"
+		manifest_path.exists(),
+		"kernel manifest path `{}` does not exist",
+		manifest_path.display()
 	);
-	let target_arch = env::var_os("CARGO_CFG_TARGET_ARCH").unwrap();
+	let target_arch = env::var("CARGO_CFG_TARGET_ARCH").unwrap();
 	let profile = env::var("PROFILE").expect("PROFILE was not set");
 	let mut cmd = Command::new("cargo");
 
+	let kernel_triple = match target_arch.as_str() {
+		"x86_64" => "x86_64-unknown-none-hermitkernel",
+		"aarch64" => "aarch64-unknown-hermit",
+		_ => panic!("Unsupported target arch: {}", target_arch),
+	};
+
+	cmd.arg("build")
+		.arg("-Z")
+		.arg("build-std=core,alloc")
+		.arg("--target")
+		.arg(kernel_triple)
+		.arg("--manifest-path")
+		.arg("Cargo.toml");
+
+	cmd.current_dir(src_dir);
+
 	cmd.env_remove("RUSTUP_TOOLCHAIN");
 	if option_env!("RUSTC_WORKSPACE_WRAPPER")
 		.unwrap_or_default()
@@ -29,24 +47,6 @@ fn build_hermit(src_dir: &Path, target_dir_opt: Option<&Path>) {
 
 	cmd.env("CARGO_TERM_COLOR", "always");
 
-	if target_arch == "x86_64" {
-		cmd.current_dir(src_dir)
-			.arg("build")
-			.arg("-Z")
-			.arg("build-std=core,alloc")
-			.arg("--target")
-			.arg("x86_64-unknown-none-hermitkernel");
-	} else if target_arch == "aarch64" {
-		cmd.current_dir(src_dir)
-			.arg("build")
-			.arg("-Z")
-			.arg("build-std=core,alloc")
-			.arg("--target")
-			.arg("aarch64-unknown-hermit");
-	} else {
-		panic!("Try to build for an unsupported platform");
-	}
-
 	if let Some(target_dir) = target_dir_opt {
 		cmd.arg("--target-dir").arg(target_dir);
 	}
@@ -130,21 +130,12 @@ fn build_hermit(src_dir: &Path, target_dir_opt: Option<&Path>) {
 	let status = cmd.status().expect("failed to start kernel build");
 	assert!(status.success());
 
-	let lib_location = if target_arch == "x86_64" {
-		target_dir
-			.join("x86_64-unknown-none-hermitkernel")
-			.join(&profile)
-			.canonicalize()
-			.unwrap() // Must exist after building
-	} else if target_arch == "aarch64" {
-		target_dir
-			.join("aarch64-unknown-hermit")
-			.join(&profile)
-			.canonicalize()
-			.unwrap() // Must exist after building
-	} else {
-		panic!("Try to build for an unsupported platform");
-	};
+	let lib_location = target_dir
+		.join(kernel_triple)
+		.join(&profile)
+		.canonicalize()
+		.unwrap();
+
 	println!("Lib location: {}", lib_location.display());
 
 	let lib = lib_location.join("libhermit.a");