Merge pull request #490 from zyuiop/feat/boot-args-file

feat: add boot args via file for EFI loader

Author: mkroening

src/arch/x86_64/firecracker.rs

@@ -1,3 +1,4 @@
+use alloc::borrow::ToOwned;
 use core::ptr::write_bytes;
 use core::{ptr, slice};
 
@@ -217,7 +218,7 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 	info!("Found available RAM: [{start_address:#x} - {end_address:#x}]");
 
 	if let Some(command_line) = command_line {
-		fdt = fdt.bootargs(command_line).unwrap();
+		fdt = fdt.bootargs(command_line.to_owned()).unwrap();
 	}
 
 	let fdt = fdt.finish().unwrap();

src/arch/x86_64/multiboot.rs

@@ -1,3 +1,4 @@
+use alloc::borrow::ToOwned;
 use core::ptr::write_bytes;
 use core::{mem, ptr, slice};
 
@@ -65,7 +66,7 @@ impl DeviceTree {
 		let mut fdt = Fdt::new("multiboot")?.memory_regions(memory_regions)?;
 
 		if let Some(cmdline) = multiboot.command_line() {
-			fdt = fdt.bootargs(cmdline)?;
+			fdt = fdt.bootargs(cmdline.to_owned())?;
 		}
 
 		let fdt = fdt.finish()?;

src/fdt.rs

@@ -1,16 +1,17 @@
 use alloc::format;
+use alloc::string::String;
 use alloc::vec::Vec;
 use core::ops::Range;
 
 use vm_fdt::{FdtWriter, FdtWriterNode, FdtWriterResult};
 
-pub struct Fdt<'a> {
+pub struct Fdt {
 	writer: FdtWriter,
 	root_node: FdtWriterNode,
-	bootargs: Option<&'a str>,
+	bootargs: Option<String>,
 }
 
-impl<'a> Fdt<'a> {
+impl Fdt {
 	pub fn new(platform: &str) -> FdtWriterResult<Self> {
 		let mut writer = FdtWriter::new()?;
 
@@ -30,7 +31,7 @@ impl<'a> Fdt<'a> {
 
 	pub fn finish(mut self) -> FdtWriterResult<Vec<u8>> {
 		let chosen_node = self.writer.begin_node("chosen")?;
-		if let Some(bootargs) = self.bootargs {
+		if let Some(bootargs) = &self.bootargs {
 			self.writer.property_string("bootargs", bootargs)?;
 		}
 		self.writer.end_node(chosen_node)?;
@@ -40,8 +41,7 @@ impl<'a> Fdt<'a> {
 		self.writer.finish()
 	}
 
-	#[cfg_attr(target_os = "uefi", expect(unused))]
-	pub fn bootargs(mut self, bootargs: &'a str) -> FdtWriterResult<Self> {
+	pub fn bootargs(mut self, bootargs: String) -> FdtWriterResult<Self> {
 		assert!(self.bootargs.is_none());
 		self.bootargs = Some(bootargs);
 
@@ -75,7 +75,7 @@ mod x86_64 {
 	use multiboot::information::{MemoryMapIter, MemoryType};
 	use vm_fdt::FdtWriterResult;
 
-	impl super::Fdt<'_> {
+	impl super::Fdt {
 		pub fn memory_regions(
 			mut self,
 			memory_regions: MemoryMapIter<'_, '_>,
@@ -105,7 +105,7 @@ mod uefi {
 	use uefi::mem::memory_map::{MemoryMap, MemoryMapMut};
 	use vm_fdt::FdtWriterResult;
 
-	impl super::Fdt<'_> {
+	impl super::Fdt {
 		pub fn memory_map(mut self, memory_map: &mut impl MemoryMapMut) -> FdtWriterResult<Self> {
 			memory_map.sort();
 			info!("Memory map:\n{}", memory_map.display());

src/os/uefi/mod.rs

@@ -1,6 +1,7 @@
 mod allocator;
 mod console;
 
+use alloc::string::String;
 use alloc::vec::Vec;
 use core::ffi::c_void;
 use core::mem::MaybeUninit;
@@ -14,7 +15,7 @@ use hermit_entry::elf::{KernelObject, LoadedKernel};
 use log::info;
 use sptr::Strict;
 use uefi::boot::{AllocateType, MemoryType, PAGE_SIZE};
-use uefi::fs::{FileSystem, Path};
+use uefi::fs::{self, FileSystem, Path};
 use uefi::prelude::*;
 use uefi::table::cfg;
 
@@ -40,11 +41,15 @@ fn main() -> Status {
 
 	drop(kernel_image);
 
-	let fdt = Fdt::new("uefi")
+	let mut fdt = Fdt::new("uefi")
 		.unwrap()
 		.rsdp(u64::try_from(rsdp.expose_addr()).unwrap())
 		.unwrap();
 
+	if let Some(bootargs) = read_bootargs() {
+		fdt = fdt.bootargs(bootargs).unwrap();
+	}
+
 	allocator::exit_boot_services();
 	let mut memory_map = unsafe { boot::exit_boot_services(None) };
 
@@ -69,6 +74,25 @@ fn read_app() -> Vec<u8> {
 	data
 }
 
+fn read_bootargs() -> Option<String> {
+	let image_handle = boot::image_handle();
+	let fs = boot::get_image_file_system(image_handle).expect("should open file system");
+
+	let path = Path::new(cstr16!(r"\efi\boot\hermit-bootargs"));
+
+	match FileSystem::new(fs).read_to_string(path) {
+		Ok(bootargs) => {
+			info!("Read Hermit bootargs from from \"{path}\": {bootargs}");
+			Some(bootargs)
+		}
+		Err(fs::Error::Io(err)) if err.uefi_error.status() == Status::NOT_FOUND => {
+			info!("Hermit bootargs file does not exist: \"{path}\"");
+			None
+		}
+		Err(err) => panic!("{err:?}"),
+	}
+}
+
 pub unsafe fn boot_kernel(kernel_info: LoadedKernel, fdt: Vec<u8>) -> ! {
 	let LoadedKernel {
 		load_info,