build.rs

extern crate target_build_utils;
extern crate walkdir;

use std::env;
use std::ffi::OsStr;
use std::ffi::OsString;
use std::fs::File;
use std::io::Write;
use std::path::{Path, PathBuf};
use std::process::Command;
use target_build_utils::TargetInfo;
use walkdir::{DirEntry, WalkDir};

fn build_hermit(src_dir: &Path, target_dir_opt: Option<&Path>) {
	assert!(
		src_dir.exists(),
		"rusty_hermit source folder does not exist"
	);
	let target = TargetInfo::new().expect("Could not get target info");
	let profile = env::var("PROFILE").expect("PROFILE was not set");
	let mut cmd = Command::new("cargo");

	cmd.env_remove("RUSTUP_TOOLCHAIN");
	if option_env!("RUSTC_WORKSPACE_WRAPPER")
		.unwrap_or_default()
		.ends_with("clippy-driver")
	{
		cmd.env("RUSTC_WORKSPACE_WRAPPER", "clippy-driver");
	}

	cmd.env("CARGO_TERM_COLOR", "always");

	if target.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.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);
	}
	let target_dir = match target_dir_opt {
		Some(target_dir) => target_dir.to_path_buf(),
		None => src_dir.join("target"),
	};

	if profile == "release" {
		cmd.arg("--release");
	}

	// disable all default features
	cmd.arg("--no-default-features");

	if target.target_arch() == "aarch64" {
		cmd.arg("--features");
		cmd.arg("aarch64-qemu-stdout");
	}

	// do we have to enable PCI support?
	#[cfg(feature = "pci")]
	{
		cmd.arg("--features");
		cmd.arg("pci");
	}

	// do we have to enable acpi support?
	#[cfg(feature = "acpi")]
	{
		cmd.arg("--features");
		cmd.arg("acpi");
	}

	// do we have to enable FSGSBASE support?
	#[cfg(feature = "fsgs_base")]
	{
		cmd.arg("--features");
		cmd.arg("fsgs_base");
	}

	// do we support multi-processor systems?
	#[cfg(feature = "smp")]
	{
		cmd.arg("--features");
		cmd.arg("smp");
	}

	// do we have to enable VGA support
	#[cfg(feature = "vga")]
	{
		cmd.arg("--features");
		cmd.arg("vga");
	}

	let mut rustflags = vec!["-Zmutable-noalias=no".to_string()];
	let outer_rustflags = env::var("CARGO_ENCODED_RUSTFLAGS").unwrap();

	#[cfg(feature = "instrument")]
	{
		rustflags.push("-Zinstrument-mcount".to_string());
		// Add outer rustflags to command
		rustflags.push(outer_rustflags);
	}

	#[cfg(not(feature = "instrument"))]
	{
		// If the `instrument` feature feature is not enabled,
		// filter it from outer rustflags before adding them to the command.
		if !outer_rustflags.is_empty() {
			let flags = outer_rustflags
				.split('\x1f')
				.filter(|&flag| !flag.contains("instrument-mcount"))
				.map(String::from);
			rustflags.extend(flags);
		}
	}

	cmd.env("CARGO_ENCODED_RUSTFLAGS", rustflags.join("\x1f"));

	let status = cmd.status().expect("failed to start kernel build");
	assert!(status.success());

	let lib_location = if target.target_arch() == "x86_64" {
		target_dir
			.join("x86_64-unknown-none-hermitkernel")
			.join(&profile)
			.canonicalize()
			.unwrap() // Must exist after building
	} else if target.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");
	};
	println!("Lib location: {}", lib_location.display());

	let lib = lib_location.join("libhermit.a");

	rename_symbol("rust_begin_unwind", &lib);
	rename_symbol("rust_oom", &lib);

	println!("cargo:rustc-link-search=native={}", lib_location.display());
	println!("cargo:rustc-link-lib=static=hermit");

	// HERMIT_LOG_LEVEL_FILTER sets the log level filter at compile time
	println!("cargo:rerun-if-env-changed=HERMIT_LOG_LEVEL_FILTER");
}

/// Kernel and user space has its own versions of panic handler, oom handler, memcpy, memset, etc,
/// Consequently, we rename the functions in the libos to avoid collisions.
/// In addition, it provides us the offer to create a optimized version of memcpy
/// in user space.
fn rename_symbol(symbol: impl AsRef<OsStr>, lib: impl AsRef<Path>) {
	let arg = IntoIterator::into_iter([symbol.as_ref(), "=kernel-".as_ref(), symbol.as_ref()])
		.collect::<OsString>();
	let status = Command::new("rust-objcopy")
		.arg("--redefine-sym")
		.arg(arg)
		.arg(lib.as_ref())
		.status()
		.expect("Failed to execute rust-objcopy. Is cargo-binutils installed?");
	assert!(status.success(), "rust-objcopy was not successful");
}

#[cfg(all(not(feature = "rustc-dep-of-std"), not(feature = "with_submodule")))]
fn build() {
	#[cfg(windows)]
	let out_dir = env::temp_dir();
	#[cfg(not(windows))]
	let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
	let src_dir = out_dir.join("rusty-hermit");

	if !src_dir.as_path().exists() {
		let status = Command::new(env!("CARGO"))
			.current_dir(out_dir)
			.arg("download")
			.arg("--output")
			.arg(src_dir.clone().into_os_string())
			.arg("--extract")
			.arg("rusty-hermit")
			.status()
			.expect("failed to start kernel download");
		assert!(
			status.success(),
			"Unable to download rusty-hermit. Is cargo-download installed?"
		);
	}

	build_hermit(src_dir.as_ref(), None);
}

#[cfg(all(not(feature = "rustc-dep-of-std"), feature = "with_submodule"))]
fn build() {
	let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
	let target_dir = out_dir.join("target");
	let src_dir = env::current_dir()
		.unwrap()
		.parent()
		.unwrap()
		.join("libhermit-rs");

	build_hermit(src_dir.as_ref(), Some(target_dir.as_ref()));
	configure_cargo_rerun_if_changed(src_dir.as_ref());
}

#[cfg(all(not(feature = "rustc-dep-of-std"), feature = "with_submodule"))]
fn configure_cargo_rerun_if_changed(src_dir: &Path) {
	fn is_not_ignored(entry: &DirEntry) -> bool {
		// Ignore .git .vscode and target directories, but not .cargo or .github
		if entry.depth() == 1
			&& entry.path().is_dir()
			&& (entry.path().ends_with("target")
				|| entry.path().ends_with(".git")
				|| entry.path().ends_with(".vscode"))
		{
			return false;
		}
		true
	}

	WalkDir::new(src_dir)
		.into_iter()
		.filter_entry(is_not_ignored)
		.filter_map(|v| v.ok())
		.filter_map(|v| v.path().canonicalize().ok())
		.for_each(|x| println!("cargo:rerun-if-changed={}", x.display()));
}

#[cfg(not(feature = "rustc-dep-of-std"))]
fn create_constants() {
	let out_dir = env::var("OUT_DIR").expect("No out dir");
	let dest_path = Path::new(&out_dir).join("constants.rs");
	let mut f = File::create(&dest_path).expect("Could not create file");

	let ip = option_env!("HERMIT_IP");
	let ip = ip.map_or("10.0.5.3", |v| v);

	let gateway = option_env!("HERMIT_GATEWAY");
	let gateway = gateway.map_or("10.0.5.1", |v| v);

	let mask = option_env!("HERMIT_MASK");
	let mask = mask.map_or("255.255.255.0", |v| v);

	writeln!(&mut f, "const HERMIT_IP: &str = \"{}\";", ip).expect("Could not write file");
	println!("cargo:rerun-if-env-changed=HERMIT_IP");

	writeln!(&mut f, "const HERMIT_GATEWAY: &str = \"{}\";", gateway)
		.expect("Could not write file");
	println!("cargo:rerun-if-env-changed=HERMIT_GATEWAY");

	writeln!(&mut f, "const HERMIT_MASK: &str = \"{}\";", mask).expect("Could not write file");
	println!("cargo:rerun-if-env-changed=HERMIT_MASK");
}

fn main() {
	#[cfg(not(feature = "rustc-dep-of-std"))]
	create_constants();
	#[cfg(not(feature = "rustc-dep-of-std"))]
	build();
}