feat(bootloader-interface): add support for LoaderFeatures

Author: azenla

Cargo.lock

@@ -9,6 +9,7 @@ edition = "2024"
 
 [dependencies]
 anyhow = "1.0.100"
+bitflags = "2.10.0"
 toml = "0.9.8"
 log = "0.4.28"
 

Cargo.toml

@@ -1,3 +1,4 @@
+use crate::integrations::bootloader_interface::bitflags::LoaderFeatures;
 use crate::platform::timer::PlatformTimer;
 use crate::utils::device_path_subpath;
 use crate::utils::variables::{VariableClass, VariableController};
@@ -6,6 +7,9 @@ use uefi::proto::device_path::DevicePath;
 use uefi::{Guid, guid};
 use uefi_raw::table::runtime::VariableVendor;
 
+/// bitflags: LoaderFeatures bitflags.
+mod bitflags;
+
 /// The name of the bootloader to tell the system.
 const LOADER_NAME: &str = "Sprout";
 
@@ -18,6 +22,11 @@ impl BootloaderInterface {
         "4a67b082-0a4c-41cf-b6c7-440b29bb8c4f"
     )));
 
+    /// The feature we support in Sprout.
+    fn features() -> LoaderFeatures {
+        LoaderFeatures::LoadDriver | LoaderFeatures::Tpm2ActivePcrBanks | LoaderFeatures::RetainShim
+    }
+
     /// Tell the system that Sprout was initialized at the current time.
     pub fn mark_init(timer: &PlatformTimer) -> Result<()> {
         Self::mark_time("LoaderTimeInitUSec", timer)
@@ -45,13 +54,26 @@ impl BootloaderInterface {
         )
     }
 
-    /// Tell the system what loader is being used.
+    /// Tell the system what loader is being used and our features.
     pub fn set_loader_info() -> Result<()> {
-        Self::VENDOR.set_cstr16(
-            "LoaderInfo",
-            LOADER_NAME,
-            VariableClass::BootAndRuntimeTemporary,
-        )
+        // Set the LoaderInfo variable with the name of the loader.
+        Self::VENDOR
+            .set_cstr16(
+                "LoaderInfo",
+                LOADER_NAME,
+                VariableClass::BootAndRuntimeTemporary,
+            )
+            .context("unable to set loader info variable")?;
+
+        // Set the LoaderFeatures variable with the features we support.
+        Self::VENDOR
+            .set_u64le(
+                "LoaderFeatures",
+                Self::features().bits(),
+                VariableClass::BootAndRuntimeTemporary,
+            )
+            .context("unable to set loader features variable")?;
+        Ok(())
     }
 
     /// Tell the system the relative path to the partition root of the current bootloader.

src/integrations/bootloader_interface.rs

@@ -0,0 +1,46 @@
+use bitflags::bitflags;
+
+bitflags! {
+    /// Feature bitflags for the bootloader interface.
+    #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+    pub struct LoaderFeatures: u64 {
+        /// Bootloader supports LoaderConfigTimeout.
+        const ConfigTimeout = 1 << 0;
+        /// Bootloader supports LoaderConfigTimeoutOneShot.
+        const ConfigTimeoutOneShot = 1 << 1;
+        /// Bootloader supports LoaderEntryDefault.
+        const EntryDefault = 1 << 2;
+        /// Bootloader supports LoaderEntryOneShot.
+        const EntryOneShot = 1 << 3;
+        /// Bootloader supports boot counting.
+        const BootCounting = 1 << 4;
+        /// Bootloader supports detection from XBOOTLDR partitions.
+        const Xbootldr = 1 << 5;
+        /// Bootloader supports handling of random seeds.
+        const RandomSeed = 1 << 6;
+        /// Bootloader supports loading drivers.
+        const LoadDriver = 1 << 7;
+        /// Bootloader supports sort keys.
+        const SortKey = 1 << 8;
+        /// Bootloader supports saved entries.
+        const SavedEntry = 1 << 9;
+        /// Bootloader supports device trees.
+        const DeviceTree = 1 << 10;
+        /// Bootloader supports secure boot enroll.
+        const SecureBootEnroll = 1 << 11;
+        /// Bootloader retains the shim.
+        const RetainShim = 1 << 12;
+        /// Bootloader supports disabling the menu via menu timeout variable.
+        const MenuDisable = 1 << 13;
+        /// Bootloader supports multi-profile UKI.
+        const MultiProfileUki = 1 << 14;
+        /// Bootloader reports URLs.
+        const ReportUrl = 1 << 15;
+        /// Bootloader supports type-1 UKIs.
+        const Type1Uki = 1 << 16;
+        /// Bootloader supports type-1 UKI urls.
+        const Type1UkiUrl = 1 << 17;
+        /// Bootloader indicates TPM2 active PCR banks.
+        const Tpm2ActivePcrBanks = 1 << 18;
+    }
+}

src/integrations/bootloader_interface/bitflags.rs

@@ -98,4 +98,10 @@ impl VariableController {
     pub fn set_bool(&self, key: &str, value: bool, class: VariableClass) -> Result<()> {
         self.set(key, &[value as u8], class)
     }
+
+    /// Set the u64 little-endian variable specified by `key` to `value`.
+    /// The variable `class` controls the attributes for the variable.
+    pub fn set_u64le(&self, key: &str, value: u64, class: VariableClass) -> Result<()> {
+        self.set(key, &value.to_le_bytes(), class)
+    }
 }