chore(code): move crates/sprout to crates/boot and name it edera-sprout-boot

crates/boot/Cargo.toml

@@ -0,0 +1,27 @@
+[package]
+name = "edera-sprout-boot"
+description = "Sprout: Modern UEFI Bootloader"
+license.workspace = true
+version.workspace = true
+homepage.workspace = true
+repository.workspace = true
+edition.workspace = true
+
+[dependencies]
+anyhow.workspace = true
+edera-sprout-config.path = "../config"
+edera-sprout-eficore.path = "../eficore"
+hex.workspace = true
+sha2.workspace = true
+shlex.workspace = true
+toml.workspace = true
+log.workspace = true
+uefi.workspace = true
+uefi-raw.workspace = true
+
+[build-dependencies]
+edera-sprout-build.path = "../build"
+
+[[bin]]
+name = "sprout"
+path = "src/main.rs"

crates/boot/README.md

@@ -0,0 +1,3 @@
+# Sprout Bootloader
+
+The main bootable crate of the Sprout bootloader.

crates/boot/build.rs

@@ -0,0 +1,7 @@
+use edera_sprout_build::generate_sbat_module;
+
+/// Build script entry point for Sprout.
+fn main() {
+    // Generate the sbat.generated.rs file.
+    generate_sbat_module();
+}

crates/boot/src/actions.rs

@@ -0,0 +1,42 @@
+use crate::context::SproutContext;
+use alloc::rc::Rc;
+use anyhow::{Context, Result, bail};
+
+/// EFI chainloader action.
+pub mod chainload;
+/// Edera hypervisor action.
+pub mod edera;
+/// EFI console print action.
+pub mod print;
+
+/// Execute the action specified by `name` which should be stored in the
+/// root context of the provided `context`. This function may not return
+/// if the provided action executes an operating system or an EFI application
+/// that does not return control to sprout.
+pub fn execute(context: Rc<SproutContext>, name: impl AsRef<str>) -> Result<()> {
+    // Retrieve the action from the root context.
+    let Some(action) = context.root().actions().get(name.as_ref()) else {
+        bail!("unknown action '{}'", name.as_ref());
+    };
+    // Finalize the context and freeze it.
+    let context = context
+        .finalize()
+        .context("unable to finalize context")?
+        .freeze();
+
+    // Execute the action.
+    if let Some(chainload) = &action.chainload {
+        chainload::chainload(context.clone(), chainload)?;
+        return Ok(());
+    } else if let Some(print) = &action.print {
+        print::print(context.clone(), print)?;
+        return Ok(());
+    } else if let Some(edera) = &action.edera {
+        edera::edera(context.clone(), edera)?;
+        return Ok(());
+    }
+
+    // If we reach here, we don't know how to execute the action that was configured.
+    // This is likely unreachable, but we should still return an error just in case.
+    bail!("unknown action configuration");
+}

crates/boot/src/actions/chainload.rs

@@ -0,0 +1,107 @@
+use crate::context::SproutContext;
+use crate::utils;
+use alloc::boxed::Box;
+use alloc::rc::Rc;
+use anyhow::{Context, Result, bail};
+use edera_sprout_config::actions::chainload::ChainloadConfiguration;
+use eficore::bootloader_interface::BootloaderInterface;
+use eficore::media_loader::MediaLoaderHandle;
+use eficore::media_loader::constants::linux::LINUX_EFI_INITRD_MEDIA_GUID;
+use eficore::shim::{ShimInput, ShimSupport};
+use log::error;
+use uefi::CString16;
+use uefi::proto::loaded_image::LoadedImage;
+
+/// Executes the chainload action using the specified `configuration` inside the provided `context`.
+pub fn chainload(context: Rc<SproutContext>, configuration: &ChainloadConfiguration) -> Result<()> {
+    // Retrieve the current image handle of sprout.
+    let sprout_image = uefi::boot::image_handle();
+
+    // Resolve the path to the image to chainload.
+    let resolved = eficore::path::resolve_path(
+        Some(context.root().loaded_image_path()?),
+        &context.stamp(&configuration.path),
+    )
+    .context("unable to resolve chainload path")?;
+
+    // Load the image to chainload using the shim support integration.
+    // It will determine if the image needs to be loaded via the shim or can be loaded directly.
+    let image = ShimSupport::load(sprout_image, ShimInput::ResolvedPath(&resolved))?;
+
+    // Open the LoadedImage protocol of the image to chainload.
+    let mut loaded_image_protocol = uefi::boot::open_protocol_exclusive::<LoadedImage>(image)
+        .context("unable to open loaded image protocol")?;
+
+    // Stamp and combine the options to pass to the image.
+    let options =
+        utils::combine_options(configuration.options.iter().map(|item| context.stamp(item)));
+
+    // Pass the load options to the image.
+    // If no options are provided, the resulting string will be empty.
+    // The options are pinned and boxed to ensure that they are valid for the lifetime of this
+    // function, which ensures the lifetime of the options for the image runtime.
+    let options = Box::pin(
+        CString16::try_from(&options[..])
+            .context("unable to convert chainloader options to CString16")?,
+    );
+
+    if options.num_bytes() > u32::MAX as usize {
+        bail!("chainloader options too large");
+    }
+
+    // SAFETY: option size is checked to validate it is safe to pass.
+    // Additionally, the pointer is allocated and retained on heap, which makes
+    // passing the `options` pointer safe to the next image.
+    unsafe {
+        loaded_image_protocol
+            .set_load_options(options.as_ptr() as *const u8, options.num_bytes() as u32);
+    }
+
+    // Stamp the initrd path, if provided.
+    let initrd = configuration
+        .linux_initrd
+        .as_ref()
+        .map(|item| context.stamp(item));
+    // The initrd can be None or empty, so we need to collapse that into a single Option.
+    let initrd = utils::empty_is_none(initrd);
+
+    // If an initrd is provided, register it with the EFI stack.
+    let mut initrd_handle = None;
+    if let Some(linux_initrd) = initrd {
+        let content = eficore::path::read_file_contents(
+            Some(context.root().loaded_image_path()?),
+            &linux_initrd,
+        )
+        .context("unable to read linux initrd")?;
+        let handle =
+            MediaLoaderHandle::register(LINUX_EFI_INITRD_MEDIA_GUID, content.into_boxed_slice())
+                .context("unable to register linux initrd")?;
+        initrd_handle = Some(handle);
+    }
+
+    // Mark execution of an entry in the bootloader interface.
+    BootloaderInterface::mark_exec(context.root().timer())
+        .context("unable to mark execution of boot entry in bootloader interface")?;
+
+    // Start the loaded image.
+    // This call might return, or it may pass full control to another image that will never return.
+    // Capture the result to ensure we can return an error if the image fails to start, but only
+    // after the optional initrd has been unregistered.
+    let result = uefi::boot::start_image(image);
+
+    // Unregister the initrd if it was registered.
+    if let Some(initrd_handle) = initrd_handle
+        && let Err(error) = initrd_handle.unregister()
+    {
+        error!("unable to unregister linux initrd: {}", error);
+    }
+
+    // Assert there was no error starting the image.
+    result.context("unable to start image")?;
+
+    // Explicitly drop the options to clarify the lifetime.
+    drop(options);
+
+    // Return control to sprout.
+    Ok(())
+}

crates/boot/src/actions/edera.rs

@@ -0,0 +1,138 @@
+use crate::{
+    actions,
+    context::SproutContext,
+    utils::{self},
+};
+use alloc::rc::Rc;
+use alloc::string::{String, ToString};
+use alloc::{format, vec};
+use anyhow::{Context, Result};
+use edera_sprout_config::actions::chainload::ChainloadConfiguration;
+use edera_sprout_config::actions::edera::EderaConfiguration;
+use eficore::media_loader::{
+    MediaLoaderHandle,
+    constants::xen::{
+        XEN_EFI_CONFIG_MEDIA_GUID, XEN_EFI_KERNEL_MEDIA_GUID, XEN_EFI_RAMDISK_MEDIA_GUID,
+    },
+};
+use log::error;
+use uefi::Guid;
+
+/// Builds a configuration string for the Xen EFI stub using the specified `configuration`.
+fn build_xen_config(context: Rc<SproutContext>, configuration: &EderaConfiguration) -> String {
+    // Stamp xen options and combine them.
+    let xen_options = utils::combine_options(
+        configuration
+            .xen_options
+            .iter()
+            .map(|item| context.stamp(item)),
+    );
+
+    // Stamp kernel options and combine them.
+    let kernel_options = utils::combine_options(
+        configuration
+            .kernel_options
+            .iter()
+            .map(|item| context.stamp(item)),
+    );
+
+    // xen config file format is ini-like
+    [
+        // global section
+        "[global]".to_string(),
+        // default configuration section
+        "default=sprout".to_string(),
+        // configuration section for sprout
+        "[sprout]".to_string(),
+        // xen options
+        format!("options={}", xen_options),
+        // kernel options, stub replaces the kernel path
+        // the kernel is provided via media loader
+        format!("kernel=stub {}", kernel_options),
+        // required or else the last line will be ignored
+        "".to_string(),
+    ]
+    .join("\n")
+}
+
+/// Register a media loader for some `text` with the vendor `guid`.
+/// `what` should indicate some identifying value for error messages
+/// like `config` or `kernel`.
+/// Provides a [MediaLoaderHandle] that can be used to unregister the media loader.
+fn register_media_loader_text(guid: Guid, what: &str, text: String) -> Result<MediaLoaderHandle> {
+    MediaLoaderHandle::register(guid, text.as_bytes().to_vec().into_boxed_slice())
+        .context(format!("unable to register {} media loader", what)) /*  */
+}
+
+/// Register a media loader for the file `path` with the vendor `guid`.
+/// `what` should indicate some identifying value for error messages
+/// like `config` or `kernel`.
+/// Provides a [MediaLoaderHandle] that can be used to unregister the media loader.
+fn register_media_loader_file(
+    context: &Rc<SproutContext>,
+    guid: Guid,
+    what: &str,
+    path: &str,
+) -> Result<MediaLoaderHandle> {
+    // Stamp the path to the file.
+    let path = context.stamp(path);
+    // Read the file contents.
+    let content =
+        eficore::path::read_file_contents(Some(context.root().loaded_image_path()?), &path)
+            .context(format!("unable to read {} file", what))?;
+    // Register the media loader.
+    let handle = MediaLoaderHandle::register(guid, content.into_boxed_slice())
+        .context(format!("unable to register {} media loader", what))?;
+    Ok(handle)
+}
+
+/// Executes the edera action which will boot the Edera hypervisor with the specified
+/// `configuration` and `context`. This action uses Edera-specific Xen EFI stub functionality.
+pub fn edera(context: Rc<SproutContext>, configuration: &EderaConfiguration) -> Result<()> {
+    // Build the Xen config file content for this configuration.
+    let config = build_xen_config(context.clone(), configuration);
+
+    // Register the media loader for the config.
+    let config = register_media_loader_text(XEN_EFI_CONFIG_MEDIA_GUID, "config", config)
+        .context("unable to register config media loader")?;
+
+    // Register the media loaders for the kernel.
+    let kernel = register_media_loader_file(
+        &context,
+        XEN_EFI_KERNEL_MEDIA_GUID,
+        "kernel",
+        &configuration.kernel,
+    )
+    .context("unable to register kernel media loader")?;
+
+    // Create a vector of media loaders to unregister on error.
+    let mut media_loaders = vec![config, kernel];
+
+    // Register the initrd if it is provided.
+    if let Some(initrd) = utils::empty_is_none(configuration.initrd.as_ref()) {
+        let initrd =
+            register_media_loader_file(&context, XEN_EFI_RAMDISK_MEDIA_GUID, "initrd", initrd)
+                .context("unable to register initrd media loader")?;
+        media_loaders.push(initrd);
+    }
+
+    // Chainload to the Xen EFI stub.
+    let result = actions::chainload::chainload(
+        context.clone(),
+        &ChainloadConfiguration {
+            path: configuration.xen.clone(),
+            options: vec![],
+            linux_initrd: None,
+        },
+    )
+    .context("unable to chainload to xen");
+
+    // Unregister the media loaders when an error happens.
+    for media_loader in media_loaders {
+        if let Err(error) = media_loader.unregister() {
+            error!("unable to unregister media loader: {}", error);
+        }
+    }
+
+    result
+}

crates/boot/src/actions/print.rs

@@ -0,0 +1,11 @@
+use crate::context::SproutContext;
+use alloc::rc::Rc;
+use anyhow::Result;
+use edera_sprout_config::actions::print::PrintConfiguration;
+use log::info;
+
+/// Executes the print action with the specified `configuration` inside the provided `context`.
+pub fn print(context: Rc<SproutContext>, configuration: &PrintConfiguration) -> Result<()> {
+    info!("{}", context.stamp(&configuration.text));
+    Ok(())
+}

crates/boot/src/autoconfigure.rs

@@ -0,0 +1,57 @@
+use anyhow::{Context, Result};
+use edera_sprout_config::RootConfiguration;
+use uefi::fs::FileSystem;
+use uefi::proto::device_path::DevicePath;
+use uefi::proto::media::fs::SimpleFileSystem;
+
+/// bls: autodetect and configure BLS-enabled filesystems.
+pub mod bls;
+
+/// linux: autodetect and configure Linux kernels.
+/// This autoconfiguration module should not be activated
+/// on BLS-enabled filesystems as it may make duplicate entries.
+pub mod linux;
+
+/// windows: autodetect and configure Windows boot configurations.
+pub mod windows;
+
+/// Generate a [RootConfiguration] based on the environment.
+/// Intakes a `config` to use as the basis of the autoconfiguration.
+pub fn autoconfigure(config: &mut RootConfiguration) -> Result<()> {
+    // Find all the filesystems that are on the system.
+    let filesystem_handles =
+        uefi::boot::find_handles::<SimpleFileSystem>().context("unable to scan filesystems")?;
+
+    // For each filesystem that was detected, scan it for supported autoconfig mechanisms.
+    for handle in filesystem_handles {
+        // Acquire the device path root for the filesystem.
+        let root = {
+            uefi::boot::open_protocol_exclusive::<DevicePath>(handle)
+                .context("unable to get root for filesystem")?
+                .to_boxed()
+        };
+
+        // Open the filesystem that was detected.
+        let filesystem = uefi::boot::open_protocol_exclusive::<SimpleFileSystem>(handle)
+            .context("unable to open filesystem")?;
+
+        // Trade the filesystem protocol for the uefi filesystem helper.
+        let mut filesystem = FileSystem::new(filesystem);
+
+        // Scan the filesystem for BLS supported configurations.
+        let bls_found = bls::scan(&mut filesystem, &root, config)
+            .context("unable to scan for bls configurations")?;
+
+        // If BLS was not found, scan for Linux configurations.
+        if !bls_found {
+            linux::scan(&mut filesystem, &root, config)
+                .context("unable to scan for linux configurations")?;
+        }
+
+        // Always look for Windows configurations.
+        windows::scan(&mut filesystem, &root, config)
+            .context("unable to scan for windows configurations")?;
+    }
+
+    Ok(())
+}

crates/boot/src/autoconfigure/bls.rs

@@ -0,0 +1,103 @@
+use crate::utils;
+use alloc::string::ToString;
+use alloc::{format, vec};
+use anyhow::{Context, Result};
+use edera_sprout_config::RootConfiguration;
+use edera_sprout_config::actions::ActionDeclaration;
+use edera_sprout_config::actions::chainload::ChainloadConfiguration;
+use edera_sprout_config::entries::EntryDeclaration;
+use edera_sprout_config::generators::GeneratorDeclaration;
+use edera_sprout_config::generators::bls::BlsConfiguration;
+use uefi::cstr16;
+use uefi::fs::{FileSystem, Path};
+use uefi::proto::device_path::DevicePath;
+use uefi::proto::device_path::text::{AllowShortcuts, DisplayOnly};
+
+/// The name prefix of the BLS chainload action that will be used
+/// by the BLS generator to chainload entries.
+const BLS_CHAINLOAD_ACTION_PREFIX: &str = "bls-chainload-";
+
+/// Scan the specified `filesystem` for BLS configurations.
+pub fn scan(
+    filesystem: &mut FileSystem,
+    root: &DevicePath,
+    config: &mut RootConfiguration,
+) -> Result<bool> {
+    // BLS has a loader.conf file that can specify its own auto-entries mechanism.
+    let bls_loader_conf_path = Path::new(cstr16!("\\loader\\loader.conf"));
+    // BLS also has an entries directory that can specify explicit entries.
+    let bls_entries_path = Path::new(cstr16!("\\loader\\entries"));
+
+    // Convert the device path root to a string we can use in the configuration.
+    let mut root = root
+        .to_string(DisplayOnly(false), AllowShortcuts(false))
+        .context("unable to convert device root to string")?
+        .to_string();
+    // Add a trailing forward-slash to the root to ensure the device root is completed.
+    root.push('/');
+
+    // Generate a unique hash of the root path.
+    let root_unique_hash = utils::unique_hash(&root);
+
+    // Whether we have a loader.conf file.
+    let has_loader_conf = filesystem
+        .try_exists(bls_loader_conf_path)
+        .context("unable to check for BLS loader.conf file")?;
+
+    // Whether we have an entries directory.
+    // We actually iterate the entries to see if there are any.
+    let has_entries_dir = filesystem
+        .read_dir(bls_entries_path)
+        .ok()
+        .and_then(|mut iterator| iterator.next())
+        .map(|entry| entry.is_ok())
+        .unwrap_or(false);
+
+    // Detect if a BLS supported configuration is on this filesystem.
+    // We check both loader.conf and entries directory as only one of them is required.
+    if !(has_loader_conf || has_entries_dir) {
+        return Ok(false);
+    }
+
+    // Generate a unique name for the BLS chainload action.
+    let chainload_action_name = format!("{}{}", BLS_CHAINLOAD_ACTION_PREFIX, root_unique_hash,);
+
+    // BLS is now detected, generate a configuration for it.
+    let generator = BlsConfiguration {
+        entry: EntryDeclaration {
+            title: "$title".to_string(),
+            actions: vec![chainload_action_name.clone()],
+            ..Default::default()
+        },
+        path: format!("{}\\loader", root),
+    };
+
+    // Generate a unique name for the BLS generator and insert the generator into the configuration.
+    config.generators.insert(
+        format!("auto-bls-{}", root_unique_hash),
+        GeneratorDeclaration {
+            bls: Some(generator),
+            ..Default::default()
+        },
+    );
+
+    // Generate a chainload configuration for BLS.
+    // BLS will provide these values to us.
+    let chainload = ChainloadConfiguration {
+        path: format!("{}\\$chainload", root),
+        options: vec!["$options".to_string()],
+        linux_initrd: Some(format!("{}\\$initrd", root)),
+    };
+
+    // Insert the chainload action into the configuration.
+    config.actions.insert(
+        chainload_action_name,
+        ActionDeclaration {
+            chainload: Some(chainload),
+            ..Default::default()
+        },
+    );
+
+    // We had a BLS supported configuration, so return true.
+    Ok(true)
+}

crates/boot/src/autoconfigure/linux.rs

@@ -0,0 +1,257 @@
+use crate::utils;
+use crate::utils::vercmp;
+use alloc::collections::BTreeMap;
+use alloc::string::{String, ToString};
+use alloc::vec::Vec;
+use alloc::{format, vec};
+use anyhow::{Context, Result};
+use edera_sprout_config::RootConfiguration;
+use edera_sprout_config::actions::ActionDeclaration;
+use edera_sprout_config::actions::chainload::ChainloadConfiguration;
+use edera_sprout_config::entries::EntryDeclaration;
+use edera_sprout_config::generators::GeneratorDeclaration;
+use edera_sprout_config::generators::list::ListConfiguration;
+use uefi::CString16;
+use uefi::fs::{FileSystem, Path, PathBuf};
+use uefi::proto::device_path::DevicePath;
+use uefi::proto::device_path::text::{AllowShortcuts, DisplayOnly};
+
+/// The name prefix of the Linux chainload action that will be used to boot Linux.
+const LINUX_CHAINLOAD_ACTION_PREFIX: &str = "linux-chainload-";
+
+/// The locations to scan for kernel pairs.
+/// We will check for symlinks and if this directory is a symlink, we will skip it.
+/// The empty string represents the root of the filesystem.
+const SCAN_LOCATIONS: &[&str] = &["\\boot", "\\"];
+
+/// Prefixes of kernel files to scan for.
+const KERNEL_PREFIXES: &[&str] = &["vmlinuz"];
+
+/// Prefixes of initramfs files to match to.
+const INITRAMFS_PREFIXES: &[&str] = &["initramfs", "initrd", "initrd.img"];
+
+/// This is really silly, but if what we are booting is the Canonical stubble stub,
+/// there is a chance it will assert that the load options are non-empty.
+/// Technically speaking, load options can be empty. However, it assumes load options
+/// have something in it. Canonical's stubble copied code from systemd that does this
+/// and then uses that code improperly by asserting that the pointer is non-null.
+/// To give a good user experience, we place a placeholder value here to ensure it's non-empty.
+/// For stubble, this code ensures the command line pointer becomes null:
+/// https://github.com/ubuntu/stubble/blob/e56643979addfb98982266018e08921c07424a0c/stub.c#L61-L64
+/// Then this code asserts on it, stopping the boot process:
+/// https://github.com/ubuntu/stubble/blob/e56643979addfb98982266018e08921c07424a0c/stub.c#L27
+const DEFAULT_LINUX_OPTIONS: &str = "placeholder";
+
+/// Pair of kernel and initramfs.
+/// This is what scanning a directory is meant to find.
+struct KernelPair {
+    /// The path to a kernel.
+    kernel: String,
+    /// The path to an initramfs, if any.
+    initramfs: Option<String>,
+}
+
+/// Scan the specified `filesystem` at `path` for [KernelPair] results.
+fn scan_directory(filesystem: &mut FileSystem, path: &str) -> Result<Vec<KernelPair>> {
+    // All the discovered kernel pairs.
+    let mut pairs = Vec::new();
+
+    // We have to special-case the root directory due to path logic in the uefi crate.
+    let is_root = path.is_empty() || path == "\\";
+
+    // Construct a filesystem path from the path string.
+    let path = CString16::try_from(path).context("unable to convert path to CString16")?;
+    let path = Path::new(&path);
+    let path = path.to_path_buf();
+
+    // Check if the path exists and is a directory.
+    let exists = filesystem
+        .metadata(&path)
+        .ok()
+        .map(|metadata| metadata.is_directory())
+        .unwrap_or(false);
+
+    // If the path does not exist, return an empty list.
+    if !exists {
+        return Ok(pairs);
+    }
+
+    // Open a directory iterator on the path to scan.
+    // Ignore errors here as in some scenarios this might fail due to symlinks.
+    let Some(directory) = filesystem.read_dir(&path).ok() else {
+        return Ok(pairs);
+    };
+
+    // Create a new path used for joining file names below.
+    // All attempts to derive paths for the files in the directory should use this instead.
+    // The uefi crate does not handle push correctly for the root directory.
+    // It will add a second slash, which will cause our path logic to fail.
+    let path_for_join = if is_root {
+        PathBuf::new()
+    } else {
+        path.clone()
+    };
+
+    // For each item in the directory, find a kernel.
+    for item in directory {
+        let item = item.context("unable to read directory item")?;
+
+        // Skip over any items that are not regular files.
+        if !item.is_regular_file() {
+            continue;
+        }
+
+        // Convert the name from a CString16 to a String.
+        let name = item.file_name().to_string();
+
+        // Convert the name to lowercase to make all of this case-insensitive.
+        let name_for_match = name.to_lowercase();
+
+        // Find a kernel prefix that matches, if any.
+        // This is case-insensitive to ensure we pick up all possibilities.
+        let Some(prefix) = KERNEL_PREFIXES.iter().find(|prefix| {
+            name_for_match == **prefix || name_for_match.starts_with(&format!("{}-", prefix))
+        }) else {
+            // Skip over anything that doesn't match a kernel prefix.
+            continue;
+        };
+
+        // Acquire the suffix of the name, this will be used to match an initramfs.
+        let suffix = &name[prefix.len()..];
+
+        // Find a matching initramfs, if any.
+        let mut initramfs_prefix_iter = INITRAMFS_PREFIXES.iter();
+        let matched_initramfs_path = loop {
+            let Some(prefix) = initramfs_prefix_iter.next() else {
+                break None;
+            };
+            // Construct an initramfs path.
+            let initramfs = format!("{}{}", prefix, suffix);
+            let initramfs = CString16::try_from(initramfs.as_str())
+                .context("unable to convert initramfs name to CString16")?;
+            let mut initramfs_path = path_for_join.clone();
+            initramfs_path.push(Path::new(&initramfs));
+
+            // Check if the initramfs path exists, if it does, break out of the loop.
+            if filesystem
+                .try_exists(&initramfs_path)
+                .context("unable to check if initramfs path exists")?
+            {
+                break Some(initramfs_path);
+            }
+        };
+
+        // Construct a kernel path from the kernel name.
+        let mut kernel = path_for_join.clone();
+        kernel.push(Path::new(&item.file_name()));
+        let kernel = kernel.to_string();
+        let initramfs = matched_initramfs_path.map(|initramfs_path| initramfs_path.to_string());
+
+        // Produce a kernel pair.
+        let pair = KernelPair { kernel, initramfs };
+        pairs.push(pair);
+    }
+
+    Ok(pairs)
+}
+
+/// Scan the specified `filesystem` for Linux kernels and matching initramfs.
+pub fn scan(
+    filesystem: &mut FileSystem,
+    root: &DevicePath,
+    config: &mut RootConfiguration,
+) -> Result<bool> {
+    let mut pairs = Vec::new();
+
+    // Convert the device path root to a string we can use in the configuration.
+    let mut root = root
+        .to_string(DisplayOnly(false), AllowShortcuts(false))
+        .context("unable to convert device root to string")?
+        .to_string();
+    // Add a trailing forward-slash to the root to ensure the device root is completed.
+    root.push('/');
+
+    // Generate a unique hash of the root path.
+    let root_unique_hash = utils::unique_hash(&root);
+
+    // Scan all locations for kernel pairs, adding them to the list.
+    for location in SCAN_LOCATIONS {
+        let scanned = scan_directory(filesystem, location)
+            .with_context(|| format!("unable to scan directory {}", location))?;
+        pairs.extend(scanned);
+    }
+
+    // If no kernel pairs were found, return false.
+    if pairs.is_empty() {
+        return Ok(false);
+    }
+
+    // Sort the kernel pairs by kernel version, if it has one, newer kernels first.
+    pairs.sort_by(|a, b| vercmp::compare_versions(&a.kernel, &b.kernel).reverse());
+
+    // Generate a unique name for the linux chainload action.
+    let chainload_action_name = format!("{}{}", LINUX_CHAINLOAD_ACTION_PREFIX, root_unique_hash,);
+
+    // Kernel pairs are detected, generate a list configuration for it.
+    let generator = ListConfiguration {
+        entry: EntryDeclaration {
+            title: "Boot Linux $name".to_string(),
+            actions: vec![chainload_action_name.clone()],
+            ..Default::default()
+        },
+        values: pairs
+            .into_iter()
+            .map(|pair| {
+                BTreeMap::from_iter(vec![
+                    ("name".to_string(), pair.kernel.clone()),
+                    ("kernel".to_string(), format!("{}{}", root, pair.kernel)),
+                    (
+                        "initrd".to_string(),
+                        pair.initramfs
+                            .map(|initramfs| format!("{}{}", root, initramfs))
+                            .unwrap_or_default(),
+                    ),
+                ])
+            })
+            .collect(),
+    };
+
+    // Generate a unique name for the Linux generator and insert the generator into the configuration.
+    config.generators.insert(
+        format!("auto-linux-{}", root_unique_hash),
+        GeneratorDeclaration {
+            list: Some(generator),
+            ..Default::default()
+        },
+    );
+
+    // Insert a default value for the linux-options if it doesn't exist.
+    if !config.values.contains_key("linux-options") {
+        config.values.insert(
+            "linux-options".to_string(),
+            DEFAULT_LINUX_OPTIONS.to_string(),
+        );
+    }
+
+    // Generate a chainload configuration for the list generator.
+    // The list will provide these values to us.
+    // Note that we don't need an extra \\ in the paths here.
+    // The root already contains a trailing slash.
+    let chainload = ChainloadConfiguration {
+        path: "$kernel".to_string(),
+        options: vec!["$linux-options".to_string()],
+        linux_initrd: Some("$initrd".to_string()),
+    };
+
+    // Insert the chainload action into the configuration.
+    config.actions.insert(
+        chainload_action_name,
+        ActionDeclaration {
+            chainload: Some(chainload),
+            ..Default::default()
+        },
+    );
+
+    // We had a Linux kernel, so return true to indicate something was found.
+    Ok(true)
+}

crates/boot/src/autoconfigure/windows.rs

@@ -0,0 +1,82 @@
+use crate::utils;
+use alloc::string::ToString;
+use alloc::{format, vec};
+use anyhow::{Context, Result};
+use edera_sprout_config::RootConfiguration;
+use edera_sprout_config::actions::ActionDeclaration;
+use edera_sprout_config::actions::chainload::ChainloadConfiguration;
+use edera_sprout_config::entries::EntryDeclaration;
+use uefi::CString16;
+use uefi::fs::{FileSystem, Path};
+use uefi::proto::device_path::DevicePath;
+use uefi::proto::device_path::text::{AllowShortcuts, DisplayOnly};
+
+/// The name prefix of the Windows chainload action that will be used to boot Windows.
+const WINDOWS_CHAINLOAD_ACTION_PREFIX: &str = "windows-chainload-";
+
+/// Windows boot manager path.
+const BOOTMGR_FW_PATH: &str = "\\EFI\\Microsoft\\Boot\\bootmgfw.efi";
+
+/// Scan the specified `filesystem` for Windows configurations.
+pub fn scan(
+    filesystem: &mut FileSystem,
+    root: &DevicePath,
+    config: &mut RootConfiguration,
+) -> Result<bool> {
+    // Convert the boot manager firmware path to a path.
+    let bootmgr_fw_path =
+        CString16::try_from(BOOTMGR_FW_PATH).context("unable to convert path to CString16")?;
+    let bootmgr_fw_path = Path::new(&bootmgr_fw_path);
+
+    // Check if the boot manager firmware path exists, if it doesn't, return false.
+    if !filesystem
+        .try_exists(bootmgr_fw_path)
+        .context("unable to check if bootmgr firmware path exists")?
+    {
+        return Ok(false);
+    }
+
+    // Convert the device path root to a string we can use in the configuration.
+    let mut root = root
+        .to_string(DisplayOnly(false), AllowShortcuts(false))
+        .context("unable to convert device root to string")?
+        .to_string();
+    // Add a trailing forward-slash to the root to ensure the device root is completed.
+    root.push('/');
+
+    // Generate a unique hash of the root path.
+    let root_unique_hash = utils::unique_hash(&root);
+
+    // Generate a unique name for the Windows chainload action.
+    let chainload_action_name = format!("{}{}", WINDOWS_CHAINLOAD_ACTION_PREFIX, root_unique_hash,);
+
+    // Generate an entry name for Windows.
+    let entry_name = format!("auto-windows-{}", root_unique_hash,);
+
+    // Create an entry for Windows and insert it into the configuration.
+    let entry = EntryDeclaration {
+        title: "Boot Windows".to_string(),
+        actions: vec![chainload_action_name.clone()],
+        values: Default::default(),
+    };
+    config.entries.insert(entry_name, entry);
+
+    // Generate a chainload configuration for Windows.
+    let chainload = ChainloadConfiguration {
+        path: format!("{}{}", root, bootmgr_fw_path),
+        options: vec![],
+        ..Default::default()
+    };
+
+    // Insert the chainload action into the configuration.
+    config.actions.insert(
+        chainload_action_name,
+        ActionDeclaration {
+            chainload: Some(chainload),
+            ..Default::default()
+        },
+    );
+
+    // We have a Windows boot entry, so return true to indicate something was found.
+    Ok(true)
+}

crates/boot/src/config.rs

@@ -0,0 +1,2 @@
+/// The configuration loader mechanisms.
+pub mod loader;

crates/boot/src/config/loader.rs

@@ -0,0 +1,68 @@
+use crate::options::SproutOptions;
+use alloc::vec::Vec;
+use anyhow::{Context, Result, bail};
+use core::ops::Deref;
+use edera_sprout_config::{RootConfiguration, latest_version};
+use eficore::platform::tpm::PlatformTpm;
+use log::info;
+use toml::Value;
+use uefi::proto::device_path::LoadedImageDevicePath;
+
+/// Loads the raw configuration from the sprout config file as data.
+fn load_raw_config(options: &SproutOptions) -> Result<Vec<u8>> {
+    // Open the LoadedImageDevicePath protocol to get the path to the current image.
+    let current_image_device_path_protocol =
+        uefi::boot::open_protocol_exclusive::<LoadedImageDevicePath>(uefi::boot::image_handle())
+            .context("unable to get loaded image device path")?;
+    // Acquire the device path as a boxed device path.
+    let path = current_image_device_path_protocol.deref().to_boxed();
+
+    info!("configuration file: {}", options.config);
+
+    // Read the contents of the sprout config file.
+    let content = eficore::path::read_file_contents(Some(&path), &options.config)
+        .context("unable to read sprout config file")?;
+
+    // Measure the sprout.toml into the TPM, if needed and possible.
+    PlatformTpm::log_event(
+        PlatformTpm::PCR_BOOT_LOADER_CONFIG,
+        &content,
+        "sprout: configuration file",
+    )
+    .context("unable to measure the sprout.toml file into the TPM")?;
+
+    // Return the contents of the sprout config file.
+    Ok(content)
+}
+
+/// Loads the [RootConfiguration] for Sprout.
+pub fn load(options: &SproutOptions) -> Result<RootConfiguration> {
+    // Load the raw configuration from the sprout config file.
+    let content = load_raw_config(options)?;
+    // Parse the raw configuration into a toml::Value which can represent any TOML file.
+    let value: Value = toml::from_slice(&content).context("unable to parse sprout config file")?;
+
+    // Check the version of the configuration without parsing the full configuration.
+    let version = value
+        .get("version")
+        .cloned()
+        .unwrap_or_else(|| Value::Integer(latest_version() as i64));
+
+    // Parse the version into an u32.
+    let version: u32 = version
+        .try_into()
+        .context("unable to get configuration version")?;
+
+    // Check if the version is supported.
+    if version != latest_version() {
+        bail!("unsupported configuration version: {}", version);
+    }
+
+    // If the version is supported, parse the full configuration.
+    let config: RootConfiguration = value
+        .try_into()
+        .context("unable to parse sprout.toml file")?;
+
+    // Return the parsed configuration.
+    Ok(config)
+}

crates/boot/src/context.rs

@@ -0,0 +1,277 @@
+use crate::options::SproutOptions;
+use alloc::boxed::Box;
+use alloc::collections::{BTreeMap, BTreeSet};
+use alloc::format;
+use alloc::rc::Rc;
+use alloc::string::{String, ToString};
+use alloc::vec::Vec;
+use anyhow::anyhow;
+use anyhow::{Result, bail};
+use core::cmp::Reverse;
+use edera_sprout_config::actions::ActionDeclaration;
+use eficore::platform::timer::PlatformTimer;
+use uefi::proto::device_path::DevicePath;
+
+/// The maximum number of iterations that can be performed in [SproutContext::finalize].
+const CONTEXT_FINALIZE_ITERATION_LIMIT: usize = 100;
+
+/// Declares a root context for Sprout.
+/// This contains data that needs to be shared across Sprout.
+pub struct RootContext {
+    /// The actions that are available in Sprout.
+    actions: BTreeMap<String, ActionDeclaration>,
+    /// The device path of the loaded Sprout image.
+    loaded_image_path: Option<Box<DevicePath>>,
+    /// Platform timer started at the beginning of the boot process.
+    timer: PlatformTimer,
+    /// The global options of Sprout.
+    options: SproutOptions,
+}
+
+impl RootContext {
+    /// Creates a new root context with the `loaded_image_device_path` which will be stored
+    /// in the context for easy access. We also provide a `timer` which is used to measure elapsed
+    /// time for the bootloader.
+    pub fn new(
+        loaded_image_device_path: Box<DevicePath>,
+        timer: PlatformTimer,
+        options: SproutOptions,
+    ) -> Self {
+        Self {
+            actions: BTreeMap::new(),
+            timer,
+            loaded_image_path: Some(loaded_image_device_path),
+            options,
+        }
+    }
+
+    /// Access the actions configured inside Sprout.
+    pub fn actions(&self) -> &BTreeMap<String, ActionDeclaration> {
+        &self.actions
+    }
+
+    /// Access the actions configured inside Sprout mutably for modification.
+    pub fn actions_mut(&mut self) -> &mut BTreeMap<String, ActionDeclaration> {
+        &mut self.actions
+    }
+
+    /// Access the platform timer that is started at the beginning of the boot process.
+    pub fn timer(&self) -> &PlatformTimer {
+        &self.timer
+    }
+
+    /// Access the device path of the loaded Sprout image.
+    pub fn loaded_image_path(&self) -> Result<&DevicePath> {
+        self.loaded_image_path
+            .as_deref()
+            .ok_or_else(|| anyhow!("no loaded image path"))
+    }
+
+    /// Access the global Sprout options.
+    pub fn options(&self) -> &SproutOptions {
+        &self.options
+    }
+}
+
+/// A context of Sprout. This is passed around different parts of Sprout and represents
+/// a [RootContext] which is data that is shared globally, and [SproutContext] which works
+/// sort of like a tree of values. You can cheaply clone a [SproutContext] and modify it with
+/// new values, which override the values of contexts above it.
+///
+/// This is a core part of the value mechanism in Sprout which makes templating possible.
+pub struct SproutContext {
+    root: Rc<RootContext>,
+    parent: Option<Rc<SproutContext>>,
+    values: BTreeMap<String, String>,
+}
+
+impl SproutContext {
+    /// Create a new [SproutContext] using `root` as the root context.
+    pub fn new(root: RootContext) -> Self {
+        Self {
+            root: Rc::new(root),
+            parent: None,
+            values: BTreeMap::new(),
+        }
+    }
+
+    /// Access the root context of this context.
+    pub fn root(&self) -> &RootContext {
+        self.root.as_ref()
+    }
+
+    /// Access the root context to modify it, if possible.
+    pub fn root_mut(&mut self) -> Option<&mut RootContext> {
+        Rc::get_mut(&mut self.root)
+    }
+
+    /// Retrieve the value specified by `key` from this context or its parents.
+    /// Returns `None` if the value is not found.
+    pub fn get(&self, key: impl AsRef<str>) -> Option<&String> {
+        self.values.get(key.as_ref()).or_else(|| {
+            self.parent
+                .as_ref()
+                .and_then(|parent| parent.get(key.as_ref()))
+        })
+    }
+
+    /// Collects all keys that are present in this context or its parents.
+    /// This is useful for iterating over all keys in a context.
+    pub fn all_keys(&self) -> Vec<String> {
+        let mut keys = BTreeSet::new();
+
+        for key in self.values.keys() {
+            keys.insert(key.clone());
+        }
+
+        if let Some(parent) = &self.parent {
+            keys.extend(parent.all_keys());
+        }
+        keys.into_iter().collect()
+    }
+
+    /// Collects all values that are present in this context or its parents.
+    /// This is useful for iterating over all values in a context.
+    pub fn all_values(&self) -> BTreeMap<String, String> {
+        let mut values = BTreeMap::new();
+        for key in self.all_keys() {
+            // Acquire the value from the context. Since retrieving all the keys will give us
+            // a full view of the context, we can be sure that the key exists.
+            let value = self.get(&key).cloned().unwrap_or_default();
+            values.insert(key.clone(), value);
+        }
+        values
+    }
+
+    /// Sets the value `key` to the value specified by `value` in this context.
+    /// If the parent context has this key, this will override that key.
+    pub fn set(&mut self, key: impl AsRef<str>, value: impl ToString) {
+        self.values
+            .insert(key.as_ref().to_string(), value.to_string());
+    }
+
+    /// Inserts all the specified `values` into this context.
+    /// These values will take precedence over its parent context.
+    pub fn insert(&mut self, values: &BTreeMap<String, String>) {
+        for (key, value) in values {
+            self.values.insert(key.clone(), value.clone());
+        }
+    }
+
+    /// Forks this context as an owned [SproutContext]. This makes it possible
+    /// to cheaply modify a context without cloning the parent context map.
+    /// The parent of the returned context is [self].
+    pub fn fork(self: &Rc<SproutContext>) -> Self {
+        Self {
+            root: self.root.clone(),
+            parent: Some(self.clone()),
+            values: BTreeMap::new(),
+        }
+    }
+
+    /// Freezes this context into a [Rc] which makes it possible to cheaply clone
+    /// and makes it less easy to modify a context. This can be used to pass the context
+    /// to various other parts of Sprout and ensure it won't be modified. Instead, once
+    /// a context is frozen, it should be [self.fork]'d to be modified.
+    pub fn freeze(self) -> Rc<SproutContext> {
+        Rc::new(self)
+    }
+
+    /// Finalizes a context by producing a context with no parent that contains all the values
+    /// of all parent contexts merged. This makes it possible to ensure [SproutContext] has no
+    /// inheritance with other [SproutContext]s. It will still contain a [RootContext] however.
+    pub fn finalize(&self) -> Result<SproutContext> {
+        // Collect all the values from the context and its parents.
+        let mut current_values = self.all_values();
+
+        // To ensure that there is no possible infinite loop, we need to check
+        // the number of iterations. If it exceeds CONTEXT_FINALIZE_ITERATION_LIMIT, we bail.
+        let mut iterations: usize = 0;
+        loop {
+            iterations += 1;
+
+            if iterations > CONTEXT_FINALIZE_ITERATION_LIMIT {
+                bail!("maximum number of replacement iterations reached while finalizing context");
+            }
+
+            let mut did_change = false;
+            let mut values = BTreeMap::new();
+            for (key, value) in &current_values {
+                let (changed, result) = Self::stamp_values(&current_values, value);
+                if changed {
+                    // If the value changed, we need to re-stamp it.
+                    did_change = true;
+                }
+                // Insert the new value into the value map.
+                values.insert(key.clone(), result);
+            }
+            current_values = values;
+
+            // If the values did not change, we can stop.
+            if !did_change {
+                break;
+            }
+        }
+
+        // Produce the final context.
+        Ok(Self {
+            root: self.root.clone(),
+            parent: None,
+            values: current_values,
+        })
+    }
+
+    /// Stamps the `text` value with the specified `values` map. The returned value indicates
+    /// whether the `text` has been changed and the value that was stamped and changed.
+    ///
+    /// Stamping works like this:
+    /// - Start with the input text.
+    /// - Sort all the keys in reverse length order (longest keys first)
+    /// - For each key, if the key is not empty, replace $KEY in the text.
+    /// - Each follow-up iteration acts upon the last iterations result.
+    /// - We keep track if the text changes during the replacement.
+    /// - We return both whether the text changed during any iteration and the final result.
+    fn stamp_values(values: &BTreeMap<String, String>, text: impl AsRef<str>) -> (bool, String) {
+        let mut result = text.as_ref().to_string();
+        let mut did_change = false;
+
+        // Sort the keys by length. This is to ensure that we stamp the longest keys first.
+        // If we did not do this, "$abc" could be stamped by "$a" into an invalid result.
+        let mut keys = values.keys().collect::<Vec<_>>();
+
+        // Sort by key length, reversed. This results in the longest keys appearing first.
+        keys.sort_by_key(|key| Reverse(key.len()));
+
+        for key in keys {
+            // Empty keys are not supported.
+            if key.is_empty() {
+                continue;
+            }
+
+            // We can fetch the value from the map. It is verifiable that the key exists.
+            let Some(value) = values.get(key) else {
+                unreachable!("keys iterated over is collected on a map that cannot be modified");
+            };
+
+            let next_result = result.replace(&format!("${key}"), value);
+            if result != next_result {
+                did_change = true;
+            }
+            result = next_result;
+        }
+        (did_change, result)
+    }
+
+    /// Stamps the input `text` with all the values in this [SproutContext] and it's parents.
+    /// For example, if this context contains {"a":"b"}, and the text "hello\\$a", it will produce
+    /// "hello\\b" as an output string.
+    pub fn stamp(&self, text: impl AsRef<str>) -> String {
+        Self::stamp_values(&self.all_values(), text.as_ref()).1
+    }
+
+    /// Unloads a [SproutContext] back into an owned context. This
+    /// may not succeed if something else is holding onto the value.
+    pub fn unload(self: Rc<SproutContext>) -> Option<SproutContext> {
+        Rc::into_inner(self)
+    }
+}

crates/boot/src/drivers.rs

@@ -0,0 +1,79 @@
+use crate::context::SproutContext;
+use alloc::collections::BTreeMap;
+use alloc::format;
+use alloc::rc::Rc;
+use alloc::string::String;
+use anyhow::{Context, Result};
+use edera_sprout_config::drivers::DriverDeclaration;
+use eficore::shim::{ShimInput, ShimSupport};
+use log::info;
+use uefi::boot::SearchType;
+
+/// Loads the driver specified by the `driver` declaration.
+fn load_driver(context: Rc<SproutContext>, driver: &DriverDeclaration) -> Result<()> {
+    // Acquire the handle and device path of the loaded image.
+    let sprout_image = uefi::boot::image_handle();
+
+    // Resolve the path to the driver image.
+    let resolved = eficore::path::resolve_path(
+        Some(context.root().loaded_image_path()?),
+        &context.stamp(&driver.path),
+    )
+    .context("unable to resolve path to driver")?;
+
+    // Load the driver image using the shim support integration.
+    // It will determine if the image needs to be loaded via the shim or can be loaded directly.
+    let image = ShimSupport::load(sprout_image, ShimInput::ResolvedPath(&resolved))?;
+
+    // Start the driver image, this is expected to return control to sprout.
+    // There is no guarantee that the driver will actually return control as it is
+    // just a standard EFI image.
+    uefi::boot::start_image(image).context("unable to start driver image")?;
+
+    Ok(())
+}
+
+/// Reconnects all handles to their controllers.
+/// This is effectively a UEFI stack reload in a sense.
+/// After we load all the drivers, we need to reconnect all of their handles
+/// so that filesystems are recognized again.
+fn reconnect() -> Result<()> {
+    // Locate all of the handles in the UEFI stack.
+    let handles = uefi::boot::locate_handle_buffer(SearchType::AllHandles)
+        .context("unable to locate handles buffer")?;
+
+    for handle in handles.iter() {
+        // Ignore the result as there is nothing we can do if reconnecting a controller fails.
+        // This is also likely to fail in some cases but should fail safely.
+        let _ = uefi::boot::connect_controller(*handle, None, None, true);
+    }
+
+    Ok(())
+}
+
+/// Load all the drivers specified in `drivers`.
+/// There is no driver order currently. This will reconnect all the controllers
+/// to all handles if at least one driver was loaded.
+pub fn load(
+    context: Rc<SproutContext>,
+    drivers: &BTreeMap<String, DriverDeclaration>,
+) -> Result<()> {
+    // If there are no drivers, we don't need to do anything.
+    if drivers.is_empty() {
+        return Ok(());
+    }
+
+    info!("loading drivers");
+
+    // Load all the drivers in no particular order.
+    for (name, driver) in drivers {
+        load_driver(context.clone(), driver).context(format!("unable to load driver: {}", name))?;
+    }
+
+    // Reconnect all the controllers to all handles.
+    reconnect().context("unable to reconnect drivers")?;
+    info!("loaded drivers");
+
+    // We've now loaded all the drivers, so we can return.
+    Ok(())
+}

crates/boot/src/entries.rs

@@ -0,0 +1,111 @@
+use crate::context::SproutContext;
+use alloc::rc::Rc;
+use alloc::string::{String, ToString};
+use edera_sprout_config::entries::EntryDeclaration;
+
+/// Represents an entry that is stamped and ready to be booted.
+#[derive(Clone)]
+pub struct BootableEntry {
+    name: String,
+    title: String,
+    context: Rc<SproutContext>,
+    declaration: EntryDeclaration,
+    default: bool,
+    pin_name: bool,
+}
+
+impl BootableEntry {
+    /// Create a new bootable entry to represent the full context of an entry.
+    pub fn new(
+        name: String,
+        title: String,
+        context: Rc<SproutContext>,
+        declaration: EntryDeclaration,
+    ) -> Self {
+        Self {
+            name,
+            title,
+            context,
+            declaration,
+            default: false,
+            pin_name: false,
+        }
+    }
+
+    /// Fetch the name of the entry. This is usually a machine-identifiable key.
+    pub fn name(&self) -> &str {
+        &self.name
+    }
+
+    /// Fetch the title of the entry. This is usually a human-readable key.
+    pub fn title(&self) -> &str {
+        &self.title
+    }
+
+    /// Fetch the full context of the entry.
+    pub fn context(&self) -> Rc<SproutContext> {
+        Rc::clone(&self.context)
+    }
+
+    /// Fetch the declaration of the entry.
+    pub fn declaration(&self) -> &EntryDeclaration {
+        &self.declaration
+    }
+
+    /// Fetch whether the entry is the default entry.
+    pub fn is_default(&self) -> bool {
+        self.default
+    }
+
+    /// Fetch whether the entry is pinned, which prevents prefixing.
+    pub fn is_pin_name(&self) -> bool {
+        self.pin_name
+    }
+
+    /// Swap out the context of the entry.
+    pub fn swap_context(&mut self, context: Rc<SproutContext>) {
+        self.context = context;
+    }
+
+    /// Restamp the title with the current context.
+    pub fn restamp_title(&mut self) {
+        self.title = self.context.stamp(&self.title);
+    }
+
+    /// Mark this entry as the default entry.
+    pub fn mark_default(&mut self) {
+        self.default = true;
+    }
+
+    // Unmark this entry as the default entry.
+    pub fn unmark_default(&mut self) {
+        self.default = false;
+    }
+
+    /// Mark this entry as being pinned, which prevents prefixing.
+    pub fn mark_pin_name(&mut self) {
+        self.pin_name = true;
+    }
+
+    /// Prepend the name of the entry with `prefix`.
+    pub fn prepend_name_prefix(&mut self, prefix: &str) {
+        self.name.insert_str(0, prefix);
+    }
+
+    /// Determine if this entry matches `needle` by comparing to the name or title of the entry.
+    pub fn is_match(&self, needle: &str) -> bool {
+        self.name == needle || self.title == needle
+    }
+
+    /// Find an entry by `needle` inside the entry iterator `haystack`.
+    /// This will search for an entry by name, title, or index.
+    pub fn find<'a>(
+        needle: &str,
+        haystack: impl Iterator<Item = &'a BootableEntry>,
+    ) -> Option<&'a BootableEntry> {
+        haystack
+            .enumerate()
+            .find(|(index, entry)| entry.is_match(needle) || index.to_string() == needle)
+            .map(|(_index, entry)| entry)
+    }
+}

crates/boot/src/extractors.rs

@@ -0,0 +1,19 @@
+use crate::context::SproutContext;
+use alloc::rc::Rc;
+use alloc::string::String;
+use anyhow::{Result, bail};
+use edera_sprout_config::extractors::ExtractorDeclaration;
+
+/// The filesystem device match extractor.
+pub mod filesystem_device_match;
+
+/// Extracts the value using the specified `extractor` under the provided `context`.
+/// The extractor must return a value, and if a value cannot be determined, an error
+/// should be returned.
+pub fn extract(context: Rc<SproutContext>, extractor: &ExtractorDeclaration) -> Result<String> {
+    if let Some(filesystem) = &extractor.filesystem_device_match {
+        filesystem_device_match::extract(context, filesystem)
+    } else {
+        bail!("unknown extractor configuration");
+    }
+}

crates/boot/src/extractors/filesystem_device_match.rs

@@ -0,0 +1,147 @@
+use crate::context::SproutContext;
+use alloc::rc::Rc;
+use alloc::string::String;
+use anyhow::{Context, Result, anyhow, bail};
+use core::ops::Deref;
+use core::str::FromStr;
+use edera_sprout_config::extractors::filesystem_device_match::FilesystemDeviceMatchExtractor;
+use eficore::partition::PartitionGuidForm;
+use uefi::fs::{FileSystem, Path};
+use uefi::proto::device_path::DevicePath;
+use uefi::proto::media::file::{File, FileSystemVolumeLabel};
+use uefi::proto::media::fs::SimpleFileSystem;
+use uefi::{CString16, Guid};
+
+/// Extract a filesystem device path using the specified `context` and `extractor` configuration.
+pub fn extract(
+    context: Rc<SproutContext>,
+    extractor: &FilesystemDeviceMatchExtractor,
+) -> Result<String> {
+    // If no criteria are provided, bail with an error.
+    if extractor.has_label.is_none()
+        && extractor.has_item.is_none()
+        && extractor.has_partition_uuid.is_none()
+        && extractor.has_partition_type_uuid.is_none()
+    {
+        bail!("at least one criteria is required for filesystem-device-match");
+    }
+
+    // Find all the filesystems inside the UEFI stack.
+    let handles = uefi::boot::find_handles::<SimpleFileSystem>()
+        .context("unable to find filesystem handles")?;
+
+    // Iterate over all the filesystems and check if they match the criteria.
+    for handle in handles {
+        // This defines whether a match has been found.
+        let mut has_match = false;
+
+        // Check if the partition info matches partition uuid criteria.
+        if let Some(ref has_partition_uuid) = extractor.has_partition_uuid {
+            // Parse the partition uuid from the extractor.
+            let parsed_uuid = Guid::from_str(has_partition_uuid)
+                .map_err(|e| anyhow!("unable to parse has-partition-uuid: {}", e))?;
+
+            // Fetch the root of the device.
+            let root = uefi::boot::open_protocol_exclusive::<DevicePath>(handle)
+                .context("unable to fetch the device path of the filesystem")?
+                .deref()
+                .to_boxed();
+
+            // Fetch the partition uuid for this filesystem.
+            let partition_uuid =
+                eficore::partition::partition_guid(&root, PartitionGuidForm::Partition)
+                    .context("unable to fetch the partition uuid of the filesystem")?;
+
+            // Compare the partition uuid to the parsed uuid.
+            // If it does not match, continue to the next filesystem.
+            if partition_uuid != Some(parsed_uuid) {
+                continue;
+            }
+            has_match = true;
+        }
+
+        // Check if the partition info matches partition type uuid criteria.
+        if let Some(ref has_partition_type_uuid) = extractor.has_partition_type_uuid {
+            // Parse the partition type uuid from the extractor.
+            let parsed_uuid = Guid::from_str(has_partition_type_uuid)
+                .map_err(|e| anyhow!("unable to parse has-partition-type-uuid: {}", e))?;
+
+            // Fetch the root of the device.
+            let root = uefi::boot::open_protocol_exclusive::<DevicePath>(handle)
+                .context("unable to fetch the device path of the filesystem")?
+                .deref()
+                .to_boxed();
+
+            // Fetch the partition type uuid for this filesystem.
+            let partition_type_uuid =
+                eficore::partition::partition_guid(&root, PartitionGuidForm::PartitionType)
+                    .context("unable to fetch the partition uuid of the filesystem")?;
+            // Compare the partition type uuid to the parsed uuid.
+            // If it does not match, continue to the next filesystem.
+            if partition_type_uuid != Some(parsed_uuid) {
+                continue;
+            }
+            has_match = true;
+        }
+
+        // Open the filesystem protocol for this handle.
+        let mut filesystem = uefi::boot::open_protocol_exclusive::<SimpleFileSystem>(handle)
+            .context("unable to open filesystem protocol")?;
+
+        // Check if the filesystem matches label criteria.
+        if let Some(ref label) = extractor.has_label {
+            let want_label = CString16::try_from(context.stamp(label).as_str())
+                .context("unable to convert label to CString16")?;
+            let mut root = filesystem
+                .open_volume()
+                .context("unable to open filesystem volume")?;
+            let label = root
+                .get_boxed_info::<FileSystemVolumeLabel>()
+                .context("unable to get filesystem volume label")?;
+
+            if label.volume_label() != want_label {
+                continue;
+            }
+            has_match = true;
+        }
+
+        // Check if the filesystem matches item criteria.
+        if let Some(ref item) = extractor.has_item {
+            let want_item = CString16::try_from(context.stamp(item).as_str())
+                .context("unable to convert item to CString16")?;
+            let mut filesystem = FileSystem::new(filesystem);
+
+            // Check the metadata of the item.
+            // Ignore filesystem errors as we can't do anything useful with the error.
+            let Some(metadata) = filesystem.metadata(Path::new(&want_item)).ok() else {
+                continue;
+            };
+
+            // Only check directories and files.
+            if !(metadata.is_directory() || metadata.is_regular_file()) {
+                continue;
+            }
+            has_match = true;
+        }
+
+        // If there is no match, continue to the next filesystem.
+        if !has_match {
+            continue;
+        }
+
+        // If we have a match, return the device root path.
+        let path = uefi::boot::open_protocol_exclusive::<DevicePath>(handle)
+            .context("unable to open filesystem device path")?;
+        let path = path.deref();
+        // Acquire the device path root as a string.
+        return eficore::path::device_path_root(path).context("unable to get device path root");
+    }
+
+    // If there is a fallback value, use it at this point.
+    if let Some(fallback) = &extractor.fallback {
+        return Ok(fallback.clone());
+    }
+
+    // Without a fallback, we can't continue, so bail.
+    bail!("unable to find matching filesystem")
+}

crates/boot/src/generators.rs

@@ -0,0 +1,34 @@
+use crate::context::SproutContext;
+use crate::entries::BootableEntry;
+use alloc::rc::Rc;
+use alloc::vec::Vec;
+use anyhow::Result;
+use anyhow::bail;
+use edera_sprout_config::generators::GeneratorDeclaration;
+
+/// The BLS generator.
+pub mod bls;
+
+/// The list generator.
+pub mod list;
+
+/// The matrix generator.
+pub mod matrix;
+
+/// Runs the generator specified by the `generator` option.
+/// It uses the specified `context` as the parent context for
+/// the generated entries, injecting more values if needed.
+pub fn generate(
+    context: Rc<SproutContext>,
+    generator: &GeneratorDeclaration,
+) -> Result<Vec<BootableEntry>> {
+    if let Some(matrix) = &generator.matrix {
+        matrix::generate(context, matrix)
+    } else if let Some(bls) = &generator.bls {
+        bls::generate(context, bls)
+    } else if let Some(list) = &generator.list {
+        list::generate(context, list)
+    } else {
+        bail!("unknown generator configuration");
+    }
+}

crates/boot/src/generators/bls.rs

@@ -0,0 +1,211 @@
+use crate::context::SproutContext;
+use crate::entries::BootableEntry;
+use crate::generators::bls::entry::BlsEntry;
+use crate::utils::vercmp;
+use alloc::format;
+use alloc::rc::Rc;
+use alloc::string::{String, ToString};
+use alloc::vec::Vec;
+use anyhow::{Context, Result};
+use core::cmp::Ordering;
+use core::str::FromStr;
+use edera_sprout_config::generators::bls::BlsConfiguration;
+use uefi::cstr16;
+use uefi::fs::{FileSystem, PathBuf};
+use uefi::proto::device_path::text::{AllowShortcuts, DisplayOnly};
+use uefi::proto::media::fs::SimpleFileSystem;
+
+/// BLS entry parser.
+mod entry;
+
+// TODO(azenla): remove this once variable substitution is implemented.
+/// This function is used to remove the `tuned_initrd` variable from entry values.
+/// Fedora uses tuned which adds an initrd that shouldn't be used.
+fn quirk_initrd_remove_tuned(input: String) -> String {
+    input.replace("$tuned_initrd", "").trim().to_string()
+}
+
+/// Sorts two entries according to the BLS sort system.
+/// Reference: https://uapi-group.org/specifications/specs/boot_loader_specification/#sorting
+fn sort_entries(a: &(BlsEntry, BootableEntry), b: &(BlsEntry, BootableEntry)) -> Ordering {
+    // Grab the components of both entries.
+    let (a_bls, a_boot) = a;
+    let (b_bls, b_boot) = b;
+
+    // Grab the sort keys from both entries.
+    let a_sort_key = a_bls.sort_key();
+    let b_sort_key = b_bls.sort_key();
+
+    // Compare the sort keys of both entries.
+    match a_sort_key.cmp(&b_sort_key) {
+        // If A and B sort keys are equal, sort by machine-id.
+        Ordering::Equal => {
+            // Grab the machine-id from both entries.
+            let a_machine_id = a_bls.machine_id();
+            let b_machine_id = b_bls.machine_id();
+
+            // Compare the machine-id of both entries.
+            match a_machine_id.cmp(&b_machine_id) {
+                // If both machine-id values are equal, sort by version.
+                Ordering::Equal => {
+                    // Grab the version from both entries.
+                    let a_version = a_bls.version();
+                    let b_version = b_bls.version();
+
+                    // Compare the version of both entries, sorting newer versions first.
+                    match vercmp::compare_versions_optional(
+                        a_version.as_deref(),
+                        b_version.as_deref(),
+                    )
+                    .reverse()
+                    {
+                        // If both versions are equal, sort by file name in reverse order.
+                        Ordering::Equal => {
+                            // Grab the file name from both entries.
+                            let a_name = a_boot.name();
+                            let b_name = b_boot.name();
+
+                            // Compare the file names of both entries, sorting newer entries first.
+                            vercmp::compare_versions(a_name, b_name).reverse()
+                        }
+                        other => other,
+                    }
+                }
+                other => other,
+            }
+        }
+
+        other => other,
+    }
+}
+
+/// Generates entries from the BLS entries directory using the specified `bls` configuration and
+/// `context`. The BLS conversion is best-effort and will ignore any unsupported entries.
+pub fn generate(context: Rc<SproutContext>, bls: &BlsConfiguration) -> Result<Vec<BootableEntry>> {
+    let mut entries = Vec::new();
+
+    // Stamp the path to the BLS directory.
+    let path = context.stamp(&bls.path);
+
+    // Resolve the path to the BLS directory.
+    let bls_resolved =
+        eficore::path::resolve_path(Some(context.root().loaded_image_path()?), &path)
+            .context("unable to resolve bls path")?;
+
+    // Construct a filesystem path to the BLS entries directory.
+    let mut entries_path = PathBuf::from(
+        bls_resolved
+            .sub_path
+            .to_string(DisplayOnly(false), AllowShortcuts(false))
+            .context("unable to convert bls path to string")?,
+    );
+    entries_path.push(cstr16!("entries"));
+
+    // Open exclusive access to the BLS filesystem.
+    let fs =
+        uefi::boot::open_protocol_exclusive::<SimpleFileSystem>(bls_resolved.filesystem_handle)
+            .context("unable to open bls filesystem")?;
+    let mut fs = FileSystem::new(fs);
+
+    // Read the BLS entries directory.
+    let entries_iter = fs
+        .read_dir(&entries_path)
+        .context("unable to read bls entries")?;
+
+    // For each entry in the BLS entries directory, parse the entry and add it to the list.
+    for entry in entries_iter {
+        // Unwrap the entry file info.
+        let entry = entry.context("unable to read bls item entry")?;
+
+        // Skip items that are not regular files.
+        if !entry.is_regular_file() {
+            continue;
+        }
+
+        // Get the file name of the filesystem item.
+        let mut name = entry.file_name().to_string();
+
+        // Ignore files that are not .conf files.
+        if !name.to_lowercase().ends_with(".conf") {
+            continue;
+        }
+
+        // Remove the .conf extension.
+        name.truncate(name.len() - 5);
+
+        // Skip over files that are named just ".conf" as they are not valid entry files.
+        if name.is_empty() {
+            continue;
+        }
+
+        // Create a mutable path so we can append the file name to produce the full path.
+        let mut full_entry_path = entries_path.to_path_buf();
+        full_entry_path.push(entry.file_name());
+
+        // Read the entry file.
+        let content = fs
+            .read(full_entry_path)
+            .context("unable to read bls file")?;
+
+        // Parse the entry file as a UTF-8 string.
+        let content = String::from_utf8(content).context("unable to read bls entry as utf8")?;
+
+        // Parse the entry file as a BLS entry.
+        let entry = BlsEntry::from_str(&content).context("unable to parse bls entry")?;
+
+        // Ignore entries that are not valid for Sprout.
+        if !entry.is_valid() {
+            continue;
+        }
+
+        // Produce a new sprout context for the entry with the extracted values.
+        let mut context = context.fork();
+
+        let title_base = entry.title().unwrap_or_else(|| name.clone());
+        let chainload = entry.chainload_path().unwrap_or_default();
+        let options = entry.options().unwrap_or_default();
+        let version = entry.version().unwrap_or_default();
+        let machine_id = entry.machine_id().unwrap_or_default();
+
+        // Put the initrd through a quirk modifier to support Fedora.
+        let initrd = quirk_initrd_remove_tuned(entry.initrd_path().unwrap_or_default());
+
+        // Combine the title with the version if a version is present, except if it already contains it.
+        // Sometimes BLS will have a version in the title already, and this makes it unique.
+        let title_full = if !version.is_empty() && !title_base.contains(&version) {
+            format!("{} {}", title_base, version)
+        } else {
+            title_base.clone()
+        };
+
+        context.set("title-base", title_base);
+        context.set("title", title_full);
+        context.set("chainload", chainload);
+        context.set("options", options);
+        context.set("initrd", initrd);
+        context.set("version", version);
+        context.set("machine-id", machine_id);
+
+        // Produce a new bootable entry.
+        let mut boot = BootableEntry::new(
+            name,
+            bls.entry.title.clone(),
+            context.freeze(),
+            bls.entry.clone(),
+        );
+
+        // Pin the entry name to prevent prefixing.
+        // This is needed as the bootloader interface requires the name to be
+        // the same as the entry file name, minus the .conf extension.
+        boot.mark_pin_name();
+
+        // Add the BLS entry to the list, along with the bootable entry.
+        entries.push((entry, boot));
+    }
+
+    // Sort all the entries according to the BLS sort system.
+    entries.sort_by(sort_entries);
+
+    // Collect all the bootable entries and return them.
+    Ok(entries.into_iter().map(|(_, boot)| boot).collect())
+}

crates/boot/src/generators/bls/entry.rs

@@ -0,0 +1,168 @@
+use alloc::string::{String, ToString};
+use anyhow::{Error, Result};
+use core::str::FromStr;
+
+/// Represents a parsed BLS entry.
+/// Fields unrelated to Sprout are not included.
+#[derive(Default, Debug, Clone)]
+pub struct BlsEntry {
+    /// The title of the entry.
+    pub title: Option<String>,
+    /// The options to pass to the entry.
+    pub options: Option<String>,
+    /// The path to the linux kernel.
+    pub linux: Option<String>,
+    /// The path to the initrd.
+    pub initrd: Option<String>,
+    /// The path to an EFI image.
+    pub efi: Option<String>,
+    /// The sort key for the entry.
+    pub sort_key: Option<String>,
+    /// The version of the entry.
+    pub version: Option<String>,
+    /// The machine id of the entry.
+    pub machine_id: Option<String>,
+}
+
+/// Parser for a BLS entry.
+impl FromStr for BlsEntry {
+    type Err = Error;
+
+    /// Parses the `input` as a BLS entry file.
+    fn from_str(input: &str) -> Result<Self> {
+        // All the fields in a BLS entry we understand.
+        // Set all to None initially.
+        let mut title: Option<String> = None;
+        let mut options: Option<String> = None;
+        let mut linux: Option<String> = None;
+        let mut initrd: Option<String> = None;
+        let mut efi: Option<String> = None;
+        let mut sort_key: Option<String> = None;
+        let mut version: Option<String> = None;
+        let mut machine_id: Option<String> = None;
+
+        // Iterate over each line in the input and parse it.
+        for line in input.lines() {
+            // Trim the line.
+            let line = line.trim();
+
+            // Skip over empty lines and comments.
+            if line.is_empty() || line.starts_with('#') {
+                continue;
+            }
+
+            // Split the line once by whitespace. This technically includes newlines but since
+            // the lines iterator is used, there should never be a newline here.
+            let Some((key, value)) = line.split_once(char::is_whitespace) else {
+                continue;
+            };
+
+            // Match the key to a field we understand.
+            match key {
+                // The title of the entry.
+                "title" => {
+                    title = Some(value.trim().to_string());
+                }
+
+                // The options to pass to the entry.
+                "options" => {
+                    options = Some(value.trim().to_string());
+                }
+
+                // The path to the linux kernel.
+                "linux" => {
+                    linux = Some(value.trim().to_string());
+                }
+
+                // The path to the initrd.
+                "initrd" => {
+                    initrd = Some(value.trim().to_string());
+                }
+
+                // The path to an EFI image.
+                "efi" => {
+                    efi = Some(value.trim().to_string());
+                }
+
+                "sort-key" => {
+                    sort_key = Some(value.trim().to_string());
+                }
+
+                "version" => {
+                    version = Some(value.trim().to_string());
+                }
+
+                "machine-id" => {
+                    machine_id = Some(value.trim().to_string());
+                }
+
+                // Ignore any other key.
+                _ => {
+                    continue;
+                }
+            }
+        }
+
+        // Produce a BLS entry from the parsed fields.
+        Ok(Self {
+            title,
+            options,
+            linux,
+            initrd,
+            efi,
+            sort_key,
+            version,
+            machine_id,
+        })
+    }
+}
+
+impl BlsEntry {
+    /// Checks if this BLS entry is something we can actually boot in Sprout.
+    pub fn is_valid(&self) -> bool {
+        self.linux.is_some() || self.efi.is_some()
+    }
+
+    /// Fetches the path to an EFI bootable image to boot, if any.
+    /// This prioritizes the linux field over efi.
+    /// It also converts / to \\ to match EFI path style.
+    pub fn chainload_path(&self) -> Option<String> {
+        self.linux
+            .clone()
+            .or(self.efi.clone())
+            .map(|path| path.replace('/', "\\").trim_start_matches('\\').to_string())
+    }
+
+    /// Fetches the path to an initrd to pass to the kernel, if any.
+    /// It also converts / to \\ to match EFI path style.
+    pub fn initrd_path(&self) -> Option<String> {
+        self.initrd
+            .clone()
+            .map(|path| path.replace('/', "\\").trim_start_matches('\\').to_string())
+    }
+
+    /// Fetches the options to pass to the kernel, if any.
+    pub fn options(&self) -> Option<String> {
+        self.options.clone()
+    }
+
+    /// Fetches the title of the entry, if any.
+    pub fn title(&self) -> Option<String> {
+        self.title.clone()
+    }
+
+    /// Fetches the sort key of the entry, if any.
+    pub fn sort_key(&self) -> Option<String> {
+        self.sort_key.clone()
+    }
+
+    /// Fetches the version of the entry, if any.
+    pub fn version(&self) -> Option<String> {
+        self.version.clone()
+    }
+
+    /// Fetches the machine id of the entry, if any.
+    pub fn machine_id(&self) -> Option<String> {
+        self.machine_id.clone()
+    }
+}

crates/boot/src/generators/list.rs

@@ -0,0 +1,40 @@
+use crate::context::SproutContext;
+use crate::entries::BootableEntry;
+use alloc::rc::Rc;
+use alloc::string::ToString;
+use alloc::vec::Vec;
+use anyhow::Result;
+use edera_sprout_config::generators::list::ListConfiguration;
+
+/// Generates a set of entries using the specified `list` configuration in the `context`.
+pub fn generate(
+    context: Rc<SproutContext>,
+    list: &ListConfiguration,
+) -> Result<Vec<BootableEntry>> {
+    let mut entries = Vec::new();
+
+    // For each combination, create a new context and entry.
+    for (index, combination) in list.values.iter().enumerate() {
+        let mut context = context.fork();
+        // Insert the combination into the context.
+        context.insert(combination);
+        let context = context.freeze();
+
+        // Stamp the entry title and actions from the template.
+        let mut entry = list.entry.clone();
+        entry.actions = entry
+            .actions
+            .into_iter()
+            .map(|action| context.stamp(action))
+            .collect();
+        // Push the entry into the list with the new context.
+        entries.push(BootableEntry::new(
+            index.to_string(),
+            entry.title.clone(),
+            context,
+            entry,
+        ));
+    }
+
+    Ok(entries)
+}

crates/boot/src/generators/matrix.rs

@@ -0,0 +1,60 @@
+use crate::context::SproutContext;
+use crate::entries::BootableEntry;
+use crate::generators::list;
+use alloc::collections::BTreeMap;
+use alloc::rc::Rc;
+use alloc::string::String;
+use alloc::vec;
+use alloc::vec::Vec;
+use anyhow::Result;
+use edera_sprout_config::generators::list::ListConfiguration;
+use edera_sprout_config::generators::matrix::MatrixConfiguration;
+
+/// Builds out multiple generations of `input` based on a matrix style.
+/// For example, if input is: {"x": ["a", "b"], "y": ["c", "d"]}
+/// It will produce:
+/// x: a, y: c
+/// x: a, y: d
+/// x: b, y: c
+/// x: b, y: d
+fn build_matrix(input: &BTreeMap<String, Vec<String>>) -> Vec<BTreeMap<String, String>> {
+    // Convert the input into a vector of tuples.
+    let items: Vec<(String, Vec<String>)> = input.clone().into_iter().collect();
+
+    // The result is a vector of maps.
+    let mut result: Vec<BTreeMap<String, String>> = vec![BTreeMap::new()];
+
+    for (key, values) in items {
+        let mut new_result = Vec::new();
+
+        // Produce all the combinations of the input values.
+        for combination in &result {
+            for value in &values {
+                let mut new_combination = combination.clone();
+                new_combination.insert(key.clone(), value.clone());
+                new_result.push(new_combination);
+            }
+        }
+
+        result = new_result;
+    }
+
+    result.into_iter().filter(|item| !item.is_empty()).collect()
+}
+
+/// Generates a set of entries using the specified `matrix` configuration in the `context`.
+pub fn generate(
+    context: Rc<SproutContext>,
+    matrix: &MatrixConfiguration,
+) -> Result<Vec<BootableEntry>> {
+    // Produce all the combinations of the input values.
+    let combinations = build_matrix(&matrix.values);
+    // Use the list generator to generate entries for each combination.
+    list::generate(
+        context,
+        &ListConfiguration {
+            entry: matrix.entry.clone(),
+            values: combinations,
+        },
+    )
+}

crates/boot/src/main.rs

@@ -0,0 +1,400 @@
+#![doc = include_str!("../README.md")]
+#![no_std]
+#![no_main]
+extern crate alloc;
+
+use crate::context::{RootContext, SproutContext};
+use crate::entries::BootableEntry;
+use crate::options::SproutOptions;
+use crate::options::parser::OptionsRepresentable;
+use crate::phases::phase;
+use alloc::collections::BTreeMap;
+use alloc::format;
+use alloc::string::ToString;
+use alloc::vec::Vec;
+use anyhow::{Context, Result, bail};
+use core::ops::Deref;
+use core::time::Duration;
+use edera_sprout_config::RootConfiguration;
+use eficore::bootloader_interface::{BootloaderInterface, BootloaderInterfaceTimeout};
+use eficore::partition::PartitionGuidForm;
+use eficore::platform::timer::PlatformTimer;
+use eficore::platform::tpm::PlatformTpm;
+use eficore::secure::SecureBoot;
+use eficore::setup;
+use log::{error, info, warn};
+use uefi::entry;
+use uefi::proto::device_path::LoadedImageDevicePath;
+use uefi_raw::Status;
+
+/// actions: Code that can be configured and executed by Sprout.
+pub mod actions;
+
+/// autoconfigure: Autoconfigure Sprout based on the detected environment.
+pub mod autoconfigure;
+
+/// config: Sprout configuration mechanism.
+pub mod config;
+
+/// context: Stored values that can be cheaply forked and cloned.
+pub mod context;
+
+/// drivers: EFI drivers to load and provide extra functionality.
+pub mod drivers;
+
+/// entries: Boot menu entries that have a title and can execute actions.
+pub mod entries;
+
+/// extractors: Runtime code that can extract values into the Sprout context.
+pub mod extractors;
+
+/// generators: Runtime code that can generate entries with specific values.
+pub mod generators;
+
+/// menu: Display a boot menu to select an entry to boot.
+pub mod menu;
+
+/// options: Parse the options of the Sprout executable.
+pub mod options;
+
+/// phases: Hooks into specific parts of the boot process.
+pub mod phases;
+
+/// sbat: Secure Boot Attestation section.
+pub mod sbat;
+
+/// utils: Utility functions that are used by other parts of Sprout.
+pub mod utils;
+
+/// The delay to wait for when an error occurs in Sprout.
+const DELAY_ON_ERROR: Duration = Duration::from_secs(10);
+
+/// Run Sprout, returning an error if one occurs.
+fn run() -> Result<()> {
+    // For safety reasons, we will note that Secure Boot is in beta on Sprout.
+    if SecureBoot::enabled().context("unable to determine Secure Boot status")? {
+        warn!("Sprout Secure Boot is in beta. Some functionality may not work as expected.");
+    }
+
+    // Start the platform timer.
+    let timer = PlatformTimer::start();
+
+    // Mark the initialization of Sprout in the bootloader interface.
+    BootloaderInterface::mark_init(&timer)
+        .context("unable to mark initialization in bootloader interface")?;
+
+    // Tell the bootloader interface what firmware we are running on.
+    BootloaderInterface::set_firmware_info()
+        .context("unable to set firmware info in bootloader interface")?;
+
+    // Tell the bootloader interface what loader is being used.
+    BootloaderInterface::set_loader_info()
+        .context("unable to set loader info in bootloader interface")?;
+
+    // Acquire the number of active PCR banks on the TPM.
+    // If no TPM is available, this will return zero.
+    let active_pcr_banks = PlatformTpm::active_pcr_banks()?;
+    // Tell the bootloader interface what the number of active PCR banks is.
+    BootloaderInterface::set_tpm2_active_pcr_banks(active_pcr_banks)
+        .context("unable to set tpm2 active PCR banks in bootloader interface")?;
+
+    // Parse the options to the sprout executable.
+    let options = SproutOptions::parse().context("unable to parse options")?;
+
+    // If --autoconfigure is specified, we use a stub configuration.
+    let mut config = if options.autoconfigure {
+        info!("autoconfiguration enabled, configuration file will be ignored");
+        RootConfiguration::default()
+    } else {
+        // Load the configuration of sprout.
+        // At this point, the configuration has been validated and the specified
+        // version is checked to ensure compatibility.
+        config::loader::load(&options)?
+    };
+
+    // Grab the sprout.efi loaded image path.
+    // This is done in a block to ensure the release of the LoadedImageDevicePath protocol.
+    let loaded_image_path = {
+        let current_image_device_path_protocol = uefi::boot::open_protocol_exclusive::<
+            LoadedImageDevicePath,
+        >(uefi::boot::image_handle())
+        .context("unable to get loaded image device path")?;
+        current_image_device_path_protocol.deref().to_boxed()
+    };
+
+    // Grab the partition GUID of the ESP that sprout was loaded from.
+    let loaded_image_partition_guid =
+        eficore::partition::partition_guid(&loaded_image_path, PartitionGuidForm::Partition)
+            .context("unable to retrieve loaded image partition guid")?;
+
+    // Set the partition GUID of the ESP that sprout was loaded from in the bootloader interface.
+    if let Some(loaded_image_partition_guid) = loaded_image_partition_guid {
+        // Tell the system about the partition GUID.
+        BootloaderInterface::set_partition_guid(&loaded_image_partition_guid)
+            .context("unable to set partition guid in bootloader interface")?;
+    }
+
+    // Tell the bootloader interface what the loaded image path is.
+    BootloaderInterface::set_loader_path(&loaded_image_path)
+        .context("unable to set loader path in bootloader interface")?;
+
+    // Create the root context.
+    let mut root = RootContext::new(loaded_image_path, timer, options);
+
+    // Insert the configuration actions into the root context.
+    root.actions_mut().extend(config.actions.clone());
+
+    // Create a new sprout context with the root context.
+    let mut context = SproutContext::new(root);
+
+    // Insert the configuration values into the sprout context.
+    context.insert(&config.values);
+
+    // Freeze the sprout context so it can be shared and cheaply cloned.
+    let context = context.freeze();
+
+    // Execute the early phase.
+    phase(context.clone(), &config.phases.early).context("unable to execute early phase")?;
+
+    // Load all configured drivers.
+    drivers::load(context.clone(), &config.drivers).context("unable to load drivers")?;
+
+    // If --autoconfigure is specified or the loaded configuration has autoconfigure enabled,
+    // trigger the autoconfiguration mechanism.
+    if context.root().options().autoconfigure || config.options.autoconfigure {
+        autoconfigure::autoconfigure(&mut config).context("unable to autoconfigure")?;
+    }
+
+    // Unload the context so that it can be modified.
+    let Some(mut context) = context.unload() else {
+        bail!("context safety violation while trying to unload context");
+    };
+
+    // Perform root context modification in a block to release the modification when complete.
+    {
+        // Modify the root context to include the autoconfigured actions.
+        let Some(root) = context.root_mut() else {
+            bail!("context safety violation while trying to modify root context");
+        };
+
+        // Extend the root context with the autoconfigured actions.
+        root.actions_mut().extend(config.actions);
+
+        // Insert any modified root values.
+        context.insert(&config.values);
+    }
+
+    // Refreeze the context to ensure that further operations can share the context.
+    let context = context.freeze();
+
+    // Run all the extractors declared in the configuration.
+    let mut extracted = BTreeMap::new();
+    for (name, extractor) in &config.extractors {
+        let value = extractors::extract(context.clone(), extractor)
+            .context(format!("unable to extract value {}", name))?;
+        info!("extracted value {}: {}", name, value);
+        extracted.insert(name.clone(), value);
+    }
+    let mut context = context.fork();
+    // Insert the extracted values into the sprout context.
+    context.insert(&extracted);
+    let context = context.freeze();
+
+    // Execute the startup phase.
+    phase(context.clone(), &config.phases.startup).context("unable to execute startup phase")?;
+
+    let mut entries = Vec::new();
+
+    // Insert all the static entries from the configuration into the entry list.
+    for (name, entry) in config.entries {
+        // Associate the main context with the static entry.
+        entries.push(BootableEntry::new(
+            name,
+            entry.title.clone(),
+            context.clone(),
+            entry,
+        ));
+    }
+
+    // Run all the generators declared in the configuration.
+    for (name, generator) in config.generators {
+        let context = context.fork().freeze();
+
+        // We will prefix all entries with [name]-, provided the name is not pinned.
+        let prefix = format!("{}-", name);
+
+        // Add all the entries generated by the generator to the entry list.
+        // The generator specifies the context associated with the entry.
+        for mut entry in generators::generate(context.clone(), &generator)? {
+            // If the entry name is not pinned, prepend the name prefix.
+            if !entry.is_pin_name() {
+                entry.prepend_name_prefix(&prefix);
+            }
+
+            entries.push(entry);
+        }
+    }
+
+    for entry in &mut entries {
+        let mut context = entry.context().fork();
+        // Insert the values from the entry configuration into the
+        // sprout context to use with the entry itself.
+        context.insert(&entry.declaration().values);
+        let context = context
+            .finalize()
+            .context("unable to finalize context")?
+            .freeze();
+        // Provide the new context to the bootable entry.
+        entry.swap_context(context);
+        // Restamp the title with any values.
+        entry.restamp_title();
+
+        // Mark this entry as the default entry if it is declared as such.
+        if let Some(ref default_entry) = config.options.default_entry {
+            // If the entry matches the default entry, mark it as the default entry.
+            if entry.is_match(default_entry) {
+                entry.mark_default();
+            }
+        }
+    }
+
+    // Tell the bootloader interface what entries are available.
+    BootloaderInterface::set_entries(entries.iter().map(|entry| entry.name()))
+        .context("unable to set entries in bootloader interface")?;
+
+    // Execute the late phase.
+    phase(context.clone(), &config.phases.late).context("unable to execute late phase")?;
+
+    // Acquire the timeout setting from the bootloader interface.
+    let bootloader_interface_timeout =
+        BootloaderInterface::get_timeout().context("unable to get bootloader interface timeout")?;
+
+    // Acquire the default entry from the bootloader interface.
+    let bootloader_interface_default_entry = BootloaderInterface::get_default_entry()
+        .context("unable to get bootloader interface default entry")?;
+
+    // Acquire the oneshot entry from the bootloader interface.
+    let bootloader_interface_oneshot_entry = BootloaderInterface::get_oneshot_entry()
+        .context("unable to get bootloader interface oneshot entry")?;
+
+    // If --boot is specified, boot that entry immediately.
+    let mut force_boot_entry = context.root().options().boot.clone();
+    // If --force-menu is specified, show the boot menu regardless of the value of --boot.
+    let mut force_boot_menu = context.root().options().force_menu;
+
+    // Determine the menu timeout in seconds based on the options or configuration.
+    // We prefer the options over the configuration to allow for overriding.
+    let mut menu_timeout = context
+        .root()
+        .options()
+        .menu_timeout
+        .unwrap_or(config.options.menu_timeout);
+
+    // Apply bootloader interface timeout settings.
+    match bootloader_interface_timeout {
+        BootloaderInterfaceTimeout::MenuForce => {
+            // Force the boot menu.
+            force_boot_menu = true;
+        }
+
+        BootloaderInterfaceTimeout::MenuHidden | BootloaderInterfaceTimeout::MenuDisabled => {
+            // Hide the boot menu by setting the timeout to zero.
+            menu_timeout = 0;
+        }
+
+        BootloaderInterfaceTimeout::Timeout(timeout) => {
+            // Configure the timeout to the specified value.
+            menu_timeout = timeout;
+        }
+
+        BootloaderInterfaceTimeout::Unspecified => {
+            // Do nothing.
+        }
+    }
+
+    // Apply bootloader interface default entry settings.
+    if let Some(ref bootloader_interface_default_entry) = bootloader_interface_default_entry {
+        // Iterate over all the entries and mark the default entry as the one specified.
+        for entry in &mut entries {
+            // Mark the entry as the default entry if it matches the specified entry.
+            // If the entry does not match the specified entry, unmark it as the default entry.
+            if entry.is_match(bootloader_interface_default_entry) {
+                entry.mark_default();
+            } else {
+                entry.unmark_default();
+            }
+        }
+    }
+
+    // Apply bootloader interface oneshot entry settings.
+    // If set, we will force booting the oneshot entry.
+    if let Some(ref bootloader_interface_oneshot_entry) = bootloader_interface_oneshot_entry {
+        force_boot_entry = Some(bootloader_interface_oneshot_entry.clone());
+    }
+
+    // If no entries were the default, pick the first entry as the default entry.
+    if entries.iter().all(|entry| !entry.is_default())
+        && let Some(entry) = entries.first_mut()
+    {
+        entry.mark_default();
+    }
+
+    // Convert the menu timeout to a duration.
+    let menu_timeout = Duration::from_secs(menu_timeout);
+
+    // Use the forced boot entry if possible, otherwise pick the first entry using a boot menu.
+    let entry = if !force_boot_menu && let Some(ref force_boot_entry) = force_boot_entry {
+        BootableEntry::find(force_boot_entry, entries.iter())
+            .context(format!("unable to find entry: {force_boot_entry}"))?
+    } else {
+        // Delegate to the menu to select an entry to boot.
+        menu::select(&timer, menu_timeout, &entries)
+            .context("unable to select entry via boot menu")?
+    };
+
+    // Tell the bootloader interface what the selected entry is.
+    BootloaderInterface::set_selected_entry(entry.name().to_string())
+        .context("unable to set selected entry in bootloader interface")?;
+
+    // Execute all the actions for the selected entry.
+    for action in &entry.declaration().actions {
+        let action = entry.context().stamp(action);
+        actions::execute(entry.context().clone(), &action)
+            .context(format!("unable to execute action '{}'", action))?;
+    }
+
+    Ok(())
+}
+
+/// The main entrypoint of sprout.
+/// It is possible this function will not return if actions that are executed
+/// exit boot services or do not return control to sprout.
+#[entry]
+fn efi_main() -> Status {
+    // Initialize the basic UEFI environment.
+    // If initialization fails, we will return ABORTED.
+    // NOTE: This function will also initialize the logger.
+    // The logger will panic if it is unable to initialize.
+    // It is guaranteed that if this returns, the logger is initialized.
+    if let Err(error) = setup::init() {
+        error!("unable to initialize environment: {}", error);
+        return Status::ABORTED;
+    }
+
+    // Run Sprout, then handle the error.
+    let result = run();
+    if let Err(ref error) = result {
+        // Print an error trace.
+        error!("sprout encountered an error:");
+        for (index, stack) in error.chain().enumerate() {
+            error!("[{}]: {}", index, stack);
+        }
+        // Sleep to allow the user to read the error.
+        uefi::boot::stall(DELAY_ON_ERROR);
+        return Status::ABORTED;
+    }
+
+    // Sprout doesn't necessarily guarantee anything was booted.
+    // If we reach here, we will exit back to whoever called us.
+    Status::SUCCESS
+}

crates/boot/src/menu.rs

@@ -0,0 +1,199 @@
+use crate::entries::BootableEntry;
+use alloc::vec;
+use anyhow::{Context, Result, bail};
+use core::time::Duration;
+use eficore::bootloader_interface::BootloaderInterface;
+use eficore::platform::timer::PlatformTimer;
+use log::{info, warn};
+use uefi::ResultExt;
+use uefi::boot::TimerTrigger;
+use uefi::proto::console::text::{Input, Key, ScanCode};
+use uefi_raw::table::boot::{EventType, Tpl};
+
+/// The characters that can be used to select an entry from keys.
+const ENTRY_NUMBER_TABLE: &[char] = &['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'];
+
+/// Represents the operation that can be performed by the boot menu.
+#[derive(PartialEq, Eq)]
+enum MenuOperation {
+    /// The user selected a numbered entry.
+    Number(usize),
+    /// The user selected the escape key to exit the boot menu.
+    Exit,
+    /// The user selected the enter key to display the entries again.
+    Continue,
+    /// Timeout occurred.
+    Timeout,
+    /// No operation should be performed.
+    Nop,
+}
+
+/// Read a key from the input device with a duration, returning the [MenuOperation] that was
+/// performed.
+fn read(input: &mut Input, timeout: &Duration) -> Result<MenuOperation> {
+    // The event to wait for a key press.
+    let key_event = input
+        .wait_for_key_event()
+        .context("unable to acquire key event")?;
+
+    // Timer event for timeout.
+    // SAFETY: The timer event creation allocated a timer pointer on the UEFI heap.
+    // This is validated safe as long as we are in boot services.
+    let timer_event = unsafe {
+        uefi::boot::create_event_ex(EventType::TIMER, Tpl::CALLBACK, None, None, None)
+            .context("unable to create timer event")?
+    };
+
+    // The timeout is in increments of 100 nanoseconds.
+    let timeout_hundred_nanos = timeout.as_nanos() / 100;
+
+    // Check if the timeout is too large to fit into an u64.
+    if timeout_hundred_nanos > u64::MAX as u128 {
+        bail!("timeout duration overflow");
+    }
+
+    // Set a timer to trigger after the specified duration.
+    let trigger = TimerTrigger::Relative(timeout_hundred_nanos as u64);
+    uefi::boot::set_timer(&timer_event, trigger).context("unable to set timeout timer")?;
+
+    let mut events = vec![timer_event, key_event];
+
+    // Wait for either the timer event or the key event to trigger.
+    // Store the result so that we can free the timer event.
+    let event_result = uefi::boot::wait_for_event(&mut events)
+        .discard_errdata()
+        .context("unable to wait for event");
+
+    // Close the timer event that we acquired.
+    // We don't need to close the key event because it is owned globally.
+    // This should always be called in practice as events are not modified by wait_for_event.
+    if let Some(timer_event) = events.into_iter().next() {
+        // Store the result of the close event so we can determine if we can safely assert it.
+        let close_event_result =
+            uefi::boot::close_event(timer_event).context("unable to close timer event");
+        if event_result.is_err()
+            && let Err(ref close_event_error) = close_event_result
+        {
+            // Log a warning if we failed to close the timer event.
+            // This is done to ensure we don't mask the wait_for_event error.
+            warn!("unable to close timer event: {}", close_event_error);
+        } else {
+            // If we reach here, we can safely assert that the close event succeeded without
+            // masking the wait_for_event error.
+            close_event_result?;
+        }
+    }
+
+    // Acquire the event that triggered.
+    let event = event_result?;
+
+    // The first event is the timer event.
+    // If it has triggered, the user did not select a numbered entry.
+    if event == 0 {
+        return Ok(MenuOperation::Timeout);
+    }
+
+    // If we reach here, there is a key event.
+    let Some(key) = input.read_key().context("unable to read key")? else {
+        bail!("no key was pressed");
+    };
+
+    match key {
+        Key::Printable(c) => {
+            // If the key is not ascii, we can't process it.
+            if !c.is_ascii() {
+                return Ok(MenuOperation::Continue);
+            }
+            // Convert the key to a char.
+            let c: char = c.into();
+            // Find the key pressed in the entry number table or continue.
+            Ok(ENTRY_NUMBER_TABLE
+                .iter()
+                .position(|&x| x == c)
+                .map(MenuOperation::Number)
+                .unwrap_or(MenuOperation::Continue))
+        }
+
+        // The escape key is used to exit the boot menu.
+        Key::Special(ScanCode::ESCAPE) => Ok(MenuOperation::Exit),
+
+        // If the special key is unknown, do nothing.
+        Key::Special(_) => Ok(MenuOperation::Nop),
+    }
+}
+
+/// Selects an entry from the list of entries using the boot menu.
+fn select_with_input<'a>(
+    input: &mut Input,
+    timeout: Duration,
+    entries: &'a [BootableEntry],
+) -> Result<&'a BootableEntry> {
+    loop {
+        // If the timeout is not zero, let's display the boot menu.
+        if !timeout.is_zero() {
+            // Until a pretty menu is available, we just print all the entries.
+            info!("Boot Menu:");
+            for (index, entry) in entries.iter().enumerate() {
+                let title = entry.context().stamp(&entry.declaration().title);
+                info!("  [{}] {}", index, title);
+            }
+        }
+
+        // Read from input until a valid operation is selected.
+        let operation = loop {
+            // If the timeout is zero, we can exit immediately because there is nothing to do.
+            if timeout.is_zero() {
+                break MenuOperation::Exit;
+            }
+
+            info!("Select a boot entry using the number keys.");
+            info!("Press Escape to exit and enter to display the entries again.");
+
+            let operation = read(input, &timeout)?;
+            if operation != MenuOperation::Nop {
+                break operation;
+            }
+        };
+
+        match operation {
+            // Entry was selected by number. If the number is invalid, we continue.
+            MenuOperation::Number(index) => {
+                let Some(entry) = entries.get(index) else {
+                    info!("invalid entry number");
+                    continue;
+                };
+                return Ok(entry);
+            }
+
+            // When the user exits the boot menu or a timeout occurs, we should
+            // boot the default entry, if any.
+            MenuOperation::Exit | MenuOperation::Timeout => {
+                return entries
+                    .iter()
+                    .find(|item| item.is_default())
+                    .context("no default entry available");
+            }
+
+            // If the operation is to continue or nop, we can just run the loop again.
+            MenuOperation::Continue | MenuOperation::Nop => {
+                continue;
+            }
+        }
+    }
+}
+
+/// Shows a boot menu to select a bootable entry to boot.
+/// The actual work is done internally in [select_with_input] which is called
+/// within the context of the standard input device.
+pub fn select<'live>(
+    timer: &'live PlatformTimer,
+    timeout: Duration,
+    entries: &'live [BootableEntry],
+) -> Result<&'live BootableEntry> {
+    // Notify the bootloader interface that we are about to display the menu.
+    BootloaderInterface::mark_menu(timer)
+        .context("unable to mark menu display in bootloader interface")?;
+
+    // Acquire the standard input device and run the boot menu.
+    uefi::system::with_stdin(move |input| select_with_input(input, timeout, entries))
+}

crates/boot/src/options.rs

@@ -0,0 +1,137 @@
+use crate::options::parser::{OptionDescription, OptionForm, OptionsRepresentable};
+use alloc::collections::BTreeMap;
+use alloc::string::{String, ToString};
+use anyhow::{Context, Result, bail};
+
+/// Acquire arguments from UEFI environment.
+pub mod env;
+
+/// The Sprout options parser.
+pub mod parser;
+
+/// Default configuration file path.
+const DEFAULT_CONFIG_PATH: &str = "\\sprout.toml";
+
+/// The parsed options of sprout.
+#[derive(Debug)]
+pub struct SproutOptions {
+    /// Configures Sprout automatically based on the environment.
+    pub autoconfigure: bool,
+    /// Path to a configuration file to load.
+    pub config: String,
+    /// Entry to boot without showing the boot menu.
+    pub boot: Option<String>,
+    /// Force display of the boot menu.
+    pub force_menu: bool,
+    /// The timeout for the boot menu in seconds.
+    pub menu_timeout: Option<u64>,
+}
+
+/// The default Sprout options.
+impl Default for SproutOptions {
+    fn default() -> Self {
+        Self {
+            autoconfigure: false,
+            config: DEFAULT_CONFIG_PATH.to_string(),
+            boot: None,
+            force_menu: false,
+            menu_timeout: None,
+        }
+    }
+}
+
+/// The options parser mechanism for Sprout.
+impl OptionsRepresentable for SproutOptions {
+    /// Produce the [SproutOptions] structure.
+    type Output = Self;
+
+    /// All the Sprout options that are defined.
+    fn options() -> &'static [(&'static str, OptionDescription<'static>)] {
+        &[
+            (
+                "autoconfigure",
+                OptionDescription {
+                    description: "Enable Sprout Autoconfiguration",
+                    form: OptionForm::Flag,
+                },
+            ),
+            (
+                "config",
+                OptionDescription {
+                    description: "Path to Sprout configuration file",
+                    form: OptionForm::Value,
+                },
+            ),
+            (
+                "boot",
+                OptionDescription {
+                    description: "Entry to boot, bypassing the menu",
+                    form: OptionForm::Value,
+                },
+            ),
+            (
+                "force-menu",
+                OptionDescription {
+                    description: "Force showing of the boot menu",
+                    form: OptionForm::Flag,
+                },
+            ),
+            (
+                "menu-timeout",
+                OptionDescription {
+                    description: "Boot menu timeout, in seconds",
+                    form: OptionForm::Value,
+                },
+            ),
+            (
+                "help",
+                OptionDescription {
+                    description: "Display Sprout Help",
+                    form: OptionForm::Help,
+                },
+            ),
+        ]
+    }
+
+    /// Produces [SproutOptions] from the parsed raw `options` map.
+    fn produce(options: BTreeMap<String, Option<String>>) -> Result<Self> {
+        // Use the default value of sprout options and have the raw options be parsed into it.
+        let mut result = Self::default();
+
+        for (key, value) in options {
+            match key.as_str() {
+                "autoconfigure" => {
+                    // Enable autoconfiguration.
+                    result.autoconfigure = true;
+                }
+
+                "config" => {
+                    // The configuration file to load.
+                    result.config = value.context("--config option requires a value")?;
+                }
+
+                "boot" => {
+                    // The entry to boot.
+                    result.boot = Some(value.context("--boot option requires a value")?);
+                }
+
+                "force-menu" => {
+                    // Force showing of the boot menu.
+                    result.force_menu = true;
+                }
+
+                "menu-timeout" => {
+                    // The timeout for the boot menu in seconds.
+                    let value = value.context("--menu-timeout option requires a value")?;
+                    let value = value
+                        .parse::<u64>()
+                        .context("menu-timeout must be a number")?;
+                    result.menu_timeout = Some(value);
+                }
+
+                _ => bail!("unknown option: --{key}"),
+            }
+        }
+        Ok(result)
+    }
+}

crates/boot/src/options/env.rs

@@ -0,0 +1,77 @@
+use alloc::string::{String, ToString};
+use alloc::vec::Vec;
+use anyhow::{Context, Result, bail};
+use uefi::proto::loaded_image::{LoadOptionsError, LoadedImage};
+
+/// Loads the command-line arguments passed to Sprout.
+pub fn args() -> Result<Vec<String>> {
+    // Acquire the image handle of Sprout.
+    let handle = uefi::boot::image_handle();
+
+    // Open the LoadedImage protocol for Sprout.
+    let loaded_image = uefi::boot::open_protocol_exclusive::<LoadedImage>(handle)
+        .context("unable to open loaded image protocol for sprout")?;
+
+    // Load the command-line argument string.
+    let options = match loaded_image.load_options_as_cstr16() {
+        // Load options were passed. We will return them for processing.
+        Ok(options) => options,
+
+        // No load options were passed. We will return an empty vector.
+        Err(LoadOptionsError::NotSet) => {
+            return Ok(Vec::new());
+        }
+
+        Err(LoadOptionsError::NotAligned) => {
+            bail!("load options are not properly aligned");
+        }
+
+        Err(LoadOptionsError::InvalidString(error)) => {
+            bail!("load options are not a valid string: {}", error);
+        }
+    };
+
+    // Convert the options to a string.
+    let options = options.to_string();
+
+    // Use shlex to parse the options.
+    // If shlex fails, we will fall back to a simple whitespace split.
+    let mut args = shlex::split(&options).unwrap_or_else(|| {
+        options
+            .split_ascii_whitespace()
+            .map(|string| string.to_string())
+            .collect::<Vec<_>>()
+    });
+
+    // If there is a first argument, check if it is not an option.
+    // If it is not, we will assume it is the path to the executable and remove it.
+    if let Some(arg) = args.first()
+        && !arg.starts_with('-')
+    {
+        args.remove(0);
+    }
+
+    // Correct firmware that may add invalid arguments at the start.
+    // Witnessed this on a Dell Precision 5690 when direct booting.
+    loop {
+        // Grab the first argument or break.
+        let Some(arg) = args.first() else {
+            break;
+        };
+
+        // Check if the argument is a valid character.
+        // If it is not, remove it and continue.
+        let Some(first_character) = arg.chars().next() else {
+            break;
+        };
+
+        // If the character is not a printable character or a backtick, remove it and continue.
+        if first_character < 0x1f as char || first_character == '`' {
+            args.remove(0);
+            continue;
+        }
+        break;
+    }
+
+    Ok(args)
+}

crates/boot/src/options/parser.rs

@@ -0,0 +1,153 @@
+use crate::options::env;
+use alloc::collections::BTreeMap;
+use alloc::string::{String, ToString};
+use anyhow::{Context, Result, bail};
+use core::ptr::null_mut;
+use log::info;
+use uefi_raw::Status;
+
+/// The type of option. This disambiguates different behavior
+/// of how options are handled.
+#[derive(Debug, Clone, Ord, PartialOrd, Eq, PartialEq)]
+pub enum OptionForm {
+    /// A flag, like --verbose.
+    Flag,
+    /// A value, in the form --abc 123 or --abc=123.
+    Value,
+    /// Help flag, like --help.
+    Help,
+}
+
+/// The description of an option, used in the options parser
+/// to make decisions about how to progress.
+#[derive(Debug, Clone)]
+pub struct OptionDescription<'a> {
+    /// The description of the option.
+    pub description: &'a str,
+    /// The type of option to parse as.
+    pub form: OptionForm,
+}
+
+/// Represents a type that can be parsed from command line arguments.
+/// This is a super minimal options parser mechanism just for Sprout.
+pub trait OptionsRepresentable {
+    /// The output type that parsing will produce.
+    type Output;
+
+    /// The configured options for this type. This should describe all the options
+    /// that are valid to produce the type. The left hand side is the name of the option,
+    /// and the right hand side is the description.
+    fn options() -> &'static [(&'static str, OptionDescription<'static>)];
+
+    /// Produces the type by taking the `options` and processing it into the output.
+    fn produce(options: BTreeMap<String, Option<String>>) -> Result<Self::Output>;
+
+    /// For minimalism, we don't want a full argument parser. Instead, we use
+    /// a simple --xyz = xyz: None and --abc 123 = abc: Some("123") format.
+    /// We also support --abc=123 = abc: Some("123") format.
+    fn parse_raw() -> Result<BTreeMap<String, Option<String>>> {
+        // Access the configured options for this type.
+        let configured: BTreeMap<_, _> = BTreeMap::from_iter(Self::options().to_vec());
+
+        // Collect all the arguments to Sprout.
+        // Skip the first argument, which is the path to our executable.
+        let args = env::args()?;
+
+        // Represent options as key-value pairs.
+        let mut options = BTreeMap::new();
+
+        // Iterators makes this way easier.
+        let mut iterator = args.into_iter().peekable();
+
+        loop {
+            // Consume the next option, if any.
+            let Some(option) = iterator.next() else {
+                break;
+            };
+
+            // If the option doesn't start with --, that is invalid.
+            if !option.starts_with("--") {
+                bail!("invalid option: {option}");
+            }
+
+            // Strip the -- prefix off.
+            let mut option = option["--".len()..].trim().to_string();
+
+            // An optional value.
+            let mut value = None;
+
+            // Check if the option is of the form --abc=123
+            if let Some((part_key, part_value)) = option.split_once('=') {
+                let part_key = part_key.to_string();
+                let part_value = part_value.to_string();
+                option = part_key;
+                value = Some(part_value);
+            }
+
+            // Error on empty option names.
+            if option.is_empty() {
+                bail!("invalid empty option");
+            }
+
+            // Find the description of the configured option, if any.
+            let Some(description) = configured.get(option.as_str()) else {
+                bail!("invalid option: --{option}");
+            };
+
+            // Check if the option requires a value and error if none was provided.
+            if description.form == OptionForm::Value && value.is_none() {
+                // Check for the next value.
+                let maybe_next = iterator.peek();
+
+                // If the next value isn't another option, set the value to the next value.
+                // Otherwise, it is None.
+                value = if let Some(next) = maybe_next
+                    && !next.starts_with("--")
+                {
+                    iterator.next()
+                } else {
+                    None
+                };
+            }
+
+            // If the option form does not support a value and there is a value, error.
+            if description.form != OptionForm::Value && value.is_some() {
+                bail!("option --{} does not take a value", option);
+            }
+
+            // Handle the --help flag case.
+            if description.form == OptionForm::Help {
+                // Generic configured options output.
+                info!("Configured Options:");
+                for (name, description) in &configured {
+                    info!(
+                        "  --{}{}: {}",
+                        name,
+                        if description.form == OptionForm::Value {
+                            " <value>"
+                        } else {
+                            ""
+                        },
+                        description.description
+                    );
+                }
+                // Exit because the help has been displayed.
+                unsafe {
+                    uefi::boot::exit(uefi::boot::image_handle(), Status::SUCCESS, 0, null_mut());
+                };
+            }
+
+            // Insert the option and the value into the map.
+            options.insert(option, value);
+        }
+        Ok(options)
+    }
+
+    /// Parses the program arguments as a [Self::Output], calling [Self::parse_raw] and [Self::produce].
+    fn parse() -> Result<Self::Output> {
+        // Parse the program arguments into a raw map.
+        let options = Self::parse_raw().context("unable to parse options")?;
+        // Produce the options from the map.
+        Self::produce(options)
+    }
+}

crates/boot/src/phases.rs

@@ -0,0 +1,26 @@
+use crate::actions;
+use crate::context::SproutContext;
+use alloc::format;
+use alloc::rc::Rc;
+use anyhow::{Context, Result};
+use edera_sprout_config::phases::PhaseConfiguration;
+
+/// Executes the specified [phase] of the boot process.
+/// The value [phase] should be a reference of a specific phase in the [PhasesConfiguration].
+/// Any error from the actions is propagated into the [Result] and will interrupt further
+/// execution of phase actions.
+pub fn phase(context: Rc<SproutContext>, phase: &[PhaseConfiguration]) -> Result<()> {
+    for item in phase {
+        let mut context = context.fork();
+        // Insert the values into the context.
+        context.insert(&item.values);
+        let context = context.freeze();
+
+        // Execute all the actions in this phase configuration.
+        for action in item.actions.iter() {
+            actions::execute(context.clone(), action)
+                .context(format!("unable to execute action '{}'", action))?;
+        }
+    }
+    Ok(())
+}

crates/boot/src/sbat.csv

@@ -0,0 +1,2 @@
+sbat,1,SBAT Version,sbat,1,https://github.com/rhboot/shim/blob/main/SBAT.md
+sprout,1,Edera,sprout,{version},https://sprout.edera.dev

crates/boot/src/sbat.rs

@@ -0,0 +1,2 @@
+// Include the generated sbat section in this file.
+include!(concat!(env!("OUT_DIR"), "/sbat.generated.rs"));

crates/boot/src/utils.rs

@@ -0,0 +1,26 @@
+use alloc::string::{String, ToString};
+use alloc::vec::Vec;
+use sha2::{Digest, Sha256};
+
+/// Implements a version comparison algorithm according to the BLS specification.
+pub mod vercmp;
+
+/// Combine a sequence of strings into a single string, separated by spaces, ignoring empty strings.
+pub fn combine_options<T: AsRef<str>>(options: impl Iterator<Item = T>) -> String {
+    options
+        .flat_map(|item| empty_is_none(Some(item)))
+        .map(|item| item.as_ref().to_string())
+        .collect::<Vec<_>>()
+        .join(" ")
+}
+
+/// Produce a unique hash for the input.
+/// This uses SHA-256, which is unique enough but relatively short.
+pub fn unique_hash(input: &str) -> String {
+    hex::encode(Sha256::digest(input.as_bytes()))
+}
+
+/// Filter a string-like Option `input` such that an empty string is [None].
+pub fn empty_is_none<T: AsRef<str>>(input: Option<T>) -> Option<T> {
+    input.filter(|input| !input.as_ref().is_empty())
+}

crates/boot/src/utils/vercmp.rs

@@ -0,0 +1,184 @@
+use core::cmp::Ordering;
+use core::iter::Peekable;
+
+/// Handles single character advancement and comparison.
+macro_rules! handle_single_char {
+    ($ca: expr, $cb:expr, $a_chars:expr, $b_chars:expr, $c:expr) => {
+        match ($ca == $c, $cb == $c) {
+            (true, false) => return Ordering::Less,
+            (false, true) => return Ordering::Greater,
+            (true, true) => {
+                $a_chars.next();
+                $b_chars.next();
+                continue;
+            }
+            _ => {}
+        }
+    };
+}
+
+/// Compares two strings using the BLS version comparison specification.
+/// Handles optional values as well by comparing only if both are specified.
+pub fn compare_versions_optional(a: Option<&str>, b: Option<&str>) -> Ordering {
+    match (a, b) {
+        // If both have values, compare them.
+        (Some(a), Some(b)) => compare_versions(a, b),
+        // If the second value is None, then `a` is less than `b`.
+        (Some(_a), None) => Ordering::Less,
+        // If the first value is None, the `a` is greater than `b`.
+        (None, Some(_b)) => Ordering::Greater,
+        // If both values are None, return that they are equal.
+        (None, None) => Ordering::Equal,
+    }
+}
+
+/// Compares two strings using the BLS version comparison specification.
+/// See: https://uapi-group.org/specifications/specs/version_format_specification/
+pub fn compare_versions(a: &str, b: &str) -> Ordering {
+    // Acquire a peekable iterator for each string.
+    let mut a_chars = a.chars().peekable();
+    let mut b_chars = b.chars().peekable();
+
+    // Loop until we have reached the end of one of the strings.
+    loop {
+        // Skip invalid characters in both strings.
+        skip_invalid(&mut a_chars);
+        skip_invalid(&mut b_chars);
+
+        // Check if either string has ended.
+        match (a_chars.peek(), b_chars.peek()) {
+            // No more characters in either string.
+            (None, None) => return Ordering::Equal,
+            // One string has ended, the other hasn't.
+            (None, Some(_)) => return Ordering::Less,
+            (Some(_), None) => return Ordering::Greater,
+            // Both strings have characters left.
+            (Some(&ca), Some(&cb)) => {
+                // Handle the ~ character.
+                handle_single_char!(ca, cb, a_chars, b_chars, '~');
+
+                // Handle '-' character.
+                handle_single_char!(ca, cb, a_chars, b_chars, '-');
+
+                // Handle the '^' character.
+                handle_single_char!(ca, cb, a_chars, b_chars, '^');
+
+                // Handle the '.' character.
+                handle_single_char!(ca, cb, a_chars, b_chars, '.');
+
+                // Handle digits with numerical comparison.
+                // We key off of the A character being a digit intentionally as we presume
+                // this indicates it will be the same at this position.
+                if ca.is_ascii_digit() || cb.is_ascii_digit() {
+                    let result = compare_numeric(&mut a_chars, &mut b_chars);
+                    if result != Ordering::Equal {
+                        return result;
+                    }
+                    continue;
+                }
+
+                // Handle letters with alphabetical comparison.
+                // We key off of the A character being alphabetical intentionally as we presume
+                // this indicates it will be the same at this position.
+                if ca.is_ascii_alphabetic() || cb.is_ascii_alphabetic() {
+                    let result = compare_alphabetic(&mut a_chars, &mut b_chars);
+                    if result != Ordering::Equal {
+                        return result;
+                    }
+                    continue;
+                }
+            }
+        }
+    }
+}
+
+/// Skips characters that are not in the valid character set.
+fn skip_invalid<I: Iterator<Item = char>>(iter: &mut Peekable<I>) {
+    while let Some(&c) = iter.peek() {
+        if is_valid_char(c) {
+            break;
+        }
+        iter.next();
+    }
+}
+
+/// Checks if a character is in the valid character set for comparison.
+fn is_valid_char(c: char) -> bool {
+    matches!(c, 'a'..='z' | 'A'..='Z' | '0'..='9' | '-' | '.' | '~' | '^')
+}
+
+/// Compares numerical prefixes by extracting numbers.
+fn compare_numeric<I: Iterator<Item = char>>(
+    iter_a: &mut Peekable<I>,
+    iter_b: &mut Peekable<I>,
+) -> Ordering {
+    let num_a = extract_number(iter_a);
+    let num_b = extract_number(iter_b);
+
+    num_a.cmp(&num_b)
+}
+
+/// Extracts a number from the iterator, skipping leading zeros.
+fn extract_number<I: Iterator<Item = char>>(iter: &mut Peekable<I>) -> u64 {
+    // Skip leading zeros
+    while let Some(&'0') = iter.peek() {
+        iter.next();
+    }
+
+    let mut num = 0u64;
+    while let Some(&c) = iter.peek() {
+        if c.is_ascii_digit() {
+            iter.next();
+            num = num.saturating_mul(10).saturating_add(c as u64 - '0' as u64);
+        } else {
+            break;
+        }
+    }
+
+    num
+}
+
+/// Compares alphabetical prefixes
+/// Capital letters compare lower than lowercase letters (B < a)
+fn compare_alphabetic<I: Iterator<Item = char>>(
+    iter_a: &mut Peekable<I>,
+    iter_b: &mut Peekable<I>,
+) -> Ordering {
+    loop {
+        return match (iter_a.peek(), iter_b.peek()) {
+            (Some(&ca), Some(&cb)) if ca.is_ascii_alphabetic() && cb.is_ascii_alphabetic() => {
+                if ca == cb {
+                    // Same character, we should continue.
+                    iter_a.next();
+                    iter_b.next();
+                    continue;
+                }
+
+                // Different characters found.
+                // All capital letters compare lower than lowercase letters.
+                match (ca.is_ascii_uppercase(), cb.is_ascii_uppercase()) {
+                    (true, false) => Ordering::Less,    // uppercase < lowercase
+                    (false, true) => Ordering::Greater, // lowercase > uppercase
+                    (true, true) => ca.cmp(&cb),        // both are uppercase
+                    (false, false) => ca.cmp(&cb),      // both are lowercase
+                }
+            }
+
+            (Some(&ca), Some(_)) if ca.is_ascii_alphabetic() => {
+                // a has letters, b doesn't
+                Ordering::Greater
+            }
+
+            (Some(_), Some(&cb)) if cb.is_ascii_alphabetic() => {
+                // b has letters, a doesn't
+                Ordering::Less
+            }
+
+            (Some(&ca), None) if ca.is_ascii_alphabetic() => Ordering::Greater,
+
+            (None, Some(&cb)) if cb.is_ascii_alphabetic() => Ordering::Less,
+
+            _ => Ordering::Equal,
+        };
+    }
+}