feat: implement decompression of Hermit images

Author: fogti

Cargo.lock

@@ -12,7 +12,9 @@ align-address = "0.4"
 allocator-api2 = { version = "0.4", default-features = false }
 anstyle = { version = "1", default-features = false }
 cfg-if = "1"
-hermit-entry = { version = "0.10", features = ["loader"] }
+compression = { version = "0.1", default-features = false, features = ["gzip"] }
+hermit-entry = { version = "0.10.8", features = ["loader"] }
+lazy_static = { version = "1.5.0", features = ["spin_no_std"] }
 log = "0.4"
 one-shot-mutex = "0.2"
 take-static = "0.1"

Cargo.toml

@@ -19,7 +19,7 @@ use log::info;
 
 use crate::BootInfoExt;
 use crate::arch::paging::*;
-use crate::os::CONSOLE;
+use crate::os::{CONSOLE, ExtraBootInfo};
 
 unsafe extern "C" {
 	static mut loader_end: u8;
@@ -106,12 +106,14 @@ pub fn find_kernel() -> &'static [u8] {
 	}
 }
 
-pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
+pub unsafe fn boot_kernel(kernel_info: LoadedKernel, extra_info: ExtraBootInfo) -> ! {
 	let LoadedKernel {
 		load_info,
 		entry_point,
 	} = kernel_info;
 
+	assert!(extra_info.image.is_none());
+
 	let fdt = unsafe {
 		Fdt::from_ptr(ptr::with_exposed_provenance(DEVICE_TREE as usize))
 			.expect(".fdt file has invalid header")

src/arch/aarch64/mod.rs

@@ -5,7 +5,7 @@ cfg_if::cfg_if! {
 	} else if #[cfg(target_arch = "riscv64")] {
 		mod riscv64;
 		pub use self::riscv64::*;
-	} else if #[cfg(all(target_arch = "x86_64"))] {
+	} else if #[cfg(target_arch = "x86_64")] {
 		mod x86_64;
 		pub use self::x86_64::*;
 	}

src/arch/mod.rs

@@ -16,6 +16,7 @@ use hermit_entry::elf::LoadedKernel;
 use log::info;
 
 use crate::BootInfoExt;
+use crate::os::ExtraBootInfo;
 
 fn find_kernel_linux(chosen: &FdtNode<'_, '_>) -> Option<&'static [u8]> {
 	let initrd_start = chosen.property("linux,initrd-start")?.as_usize()?;
@@ -89,7 +90,7 @@ pub unsafe fn get_memory(memory_size: u64) -> u64 {
 	u64::try_from(start_address).unwrap()
 }
 
-pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
+pub unsafe fn boot_kernel(kernel_info: LoadedKernel, extra_info: ExtraBootInfo) -> ! {
 	let LoadedKernel {
 		load_info,
 		entry_point,
@@ -117,6 +118,8 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 		DeviceTreeAddress::new(fdt_addr.try_into().unwrap())
 	};
 
+	assert!(extra_info.image.is_none());
+
 	let boot_info = BootInfo {
 		hardware_info: HardwareInfo {
 			phys_addr_range,

src/arch/riscv64/mod.rs

@@ -16,6 +16,7 @@ use crate::BootInfoExt;
 use crate::arch::x86_64::physicalmem::PhysAlloc;
 use crate::arch::x86_64::{KERNEL_STACK_SIZE, SERIAL_IO_PORT, paging};
 use crate::fdt::Fdt;
+use crate::os::ExtraBootInfo;
 
 unsafe extern "C" {
 	static mut loader_end: u8;
@@ -51,7 +52,7 @@ pub fn find_kernel() -> &'static [u8] {
 	boot_params_ref.map_ramdisk().unwrap()
 }
 
-pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
+pub unsafe fn boot_kernel(kernel_info: LoadedKernel, extra_info: ExtraBootInfo) -> ! {
 	let LoadedKernel {
 		load_info,
 		entry_point,
@@ -74,7 +75,12 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 		write_bytes(stack, 0, KERNEL_STACK_SIZE.try_into().unwrap());
 	}
 
-	let mut fdt = Fdt::new("linux").unwrap();
+	let maybe_image = match extra_info.image {
+		None => &[],
+		Some(tar_image) => tar_image,
+	};
+
+	let mut fdt = Fdt::new("linux", maybe_image).unwrap();
 
 	let e820_entries = boot_params_ref.e820_entries();
 	assert!(!e820_entries.is_empty());

src/arch/x86_64/platform/linux/mod.rs

@@ -16,6 +16,7 @@ use crate::BootInfoExt;
 use crate::arch::x86_64::physicalmem::PhysAlloc;
 use crate::arch::x86_64::{KERNEL_STACK_SIZE, SERIAL_IO_PORT, paging};
 use crate::fdt::Fdt;
+use crate::os::ExtraBootInfo;
 
 unsafe extern "C" {
 	static mut loader_end: u8;
@@ -53,15 +54,20 @@ impl MemoryManagement for Mem {
 pub struct DeviceTree;
 
 impl DeviceTree {
-	pub fn create() -> FdtWriterResult<&'static [u8]> {
+	pub fn create(extra_info: &ExtraBootInfo) -> FdtWriterResult<&'static [u8]> {
 		let mut mem = Mem;
 		let multiboot = unsafe { Multiboot::from_ptr(mb_info as u64, &mut mem).unwrap() };
 
 		let memory_regions = multiboot
 			.memory_regions()
 			.expect("Could not find a memory map in the Multiboot information");
 
-		let mut fdt = Fdt::new("multiboot")?.memory_regions(memory_regions)?;
+		let maybe_image = match extra_info.image {
+			None => &[],
+			Some(tar_image) => tar_image,
+		};
+
+		let mut fdt = Fdt::new("multiboot", maybe_image)?.memory_regions(memory_regions)?;
 
 		if let Some(cmdline) = multiboot.command_line() {
 			fdt = fdt.bootargs(cmdline.to_owned())?;
@@ -140,7 +146,7 @@ pub fn find_kernel() -> &'static [u8] {
 	unsafe { slice::from_raw_parts(ptr::with_exposed_provenance(elf_start), elf_len) }
 }
 
-pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
+pub unsafe fn boot_kernel(kernel_info: LoadedKernel, extra_info: ExtraBootInfo) -> ! {
 	let LoadedKernel {
 		load_info,
 		entry_point,
@@ -183,7 +189,7 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 		write_bytes(stack, 0, KERNEL_STACK_SIZE.try_into().unwrap());
 	}
 
-	let device_tree = DeviceTree::create().expect("Unable to create devicetree!");
+	let device_tree = DeviceTree::create(&extra_info).expect("Unable to create devicetree!");
 	let device_tree =
 		DeviceTreeAddress::new(u64::try_from(device_tree.as_ptr().expose_provenance()).unwrap());
 

src/arch/x86_64/platform/multiboot/mod.rs

@@ -9,31 +9,51 @@ pub struct Fdt {
 	writer: FdtWriter,
 	root_node: FdtWriterNode,
 	bootargs: Option<String>,
+	image_range: Option<(u64, u64)>,
 }
 
 impl Fdt {
-	pub fn new(platform: &str) -> FdtWriterResult<Self> {
-		let mut writer = FdtWriter::new()?;
+	pub fn new(platform: &str, maybe_image: &'static [u8]) -> FdtWriterResult<Self> {
+		let mut mem_reserved = Vec::new();
+
+		let image_range = if maybe_image.is_empty() {
+			None
+		} else {
+			let image_start = (&maybe_image[0]) as *const u8 as u64;
+			mem_reserved.push(vm_fdt::FdtReserveEntry::new(
+				image_start,
+				maybe_image.len() as u64,
+			)?);
+			Some((image_start, maybe_image.len() as u64))
+		};
+
+		let mut writer = FdtWriter::new_with_mem_reserv(&mem_reserved[..])?;
 
 		let root_node = writer.begin_node("")?;
 		writer.property_string("compatible", &format!("hermit,{platform}"))?;
 		writer.property_u32("#address-cells", 0x2)?;
 		writer.property_u32("#size-cells", 0x2)?;
 
-		let bootargs = None;
-
 		Ok(Self {
 			writer,
 			root_node,
-			bootargs,
+			bootargs: None,
+			image_range,
 		})
 	}
 
 	pub fn finish(mut self) -> FdtWriterResult<Vec<u8>> {
 		let chosen_node = self.writer.begin_node("chosen")?;
+
 		if let Some(bootargs) = &self.bootargs {
 			self.writer.property_string("bootargs", bootargs)?;
 		}
+
+		if let Some((image_start, image_len)) = self.image_range {
+			self.writer
+				.property_array_u64("image_reg", &[image_start, image_len])?;
+		}
+
 		self.writer.end_node(chosen_node)?;
 
 		self.writer.end_node(self.root_node)?;

src/fdt.rs

@@ -12,7 +12,9 @@ use hermit_entry::boot_info::{BootInfo, RawBootInfo};
 mod macros;
 
 mod arch;
+
 mod bump_allocator;
+
 #[cfg(any(target_os = "uefi", target_arch = "x86_64"))]
 mod fdt;
 mod log;
@@ -75,3 +77,41 @@ fn _print(args: core::fmt::Arguments<'_>) {
 
 	self::os::CONSOLE.lock().write_fmt(args).unwrap();
 }
+
+/// Detects the input format are resolves the kernel
+fn resolve_kernel<'a>(
+	input_blob: &'a [u8],
+	buf: &'a mut Option<alloc::boxed::Box<[u8]>>,
+) -> (&'a [u8], Option<hermit_entry::config::Config<'a>>) {
+	use hermit_entry::{Format, detect_format};
+	match detect_format(input_blob) {
+		Some(Format::Elf) => (input_blob, None),
+
+		Some(Format::Gzip) => {
+			use compression::prelude::{DecodeExt as _, GZipDecoder};
+			*buf = Some(
+				input_blob
+					.iter()
+					.copied()
+					.decode(&mut GZipDecoder::new())
+					.collect::<Result<alloc::boxed::Box<[u8]>, _>>()
+					.expect("Unable to decompress Hermit gzip image"),
+			);
+			match *buf {
+				Some(ref mut tmp) => {
+					let handle = hermit_entry::config::parse_tar(tmp)
+						.expect("Unable to find Hermit image configuration + kernel");
+
+					// TODO: do we just let the kernel handle the config
+
+					(handle.raw_kernel, Some(handle.config))
+				}
+				None => unreachable!(),
+			}
+		}
+
+		None => {
+			panic!("Input BLOB has unknown magic bytes (neither Gzip nor ELF)")
+		}
+	}
+}

src/main.rs

@@ -7,3 +7,9 @@ cfg_if::cfg_if! {
 		pub use self::uefi::*;
 	}
 }
+
+#[cfg_attr(not(target_os = "none"), allow(dead_code))]
+#[derive(Clone, Default)]
+pub struct ExtraBootInfo {
+	pub(crate) image: Option<&'static [u8]>,
+}