chore(code): move bls autoconfigure to separate module

src/autoconfigure/bls.rs

@@ -0,0 +1,97 @@
+use crate::actions::ActionDeclaration;
+use crate::actions::chainload::ChainloadConfiguration;
+use crate::config::RootConfiguration;
+use crate::entries::EntryDeclaration;
+use crate::generators::GeneratorDeclaration;
+use crate::generators::bls::BlsConfiguration;
+use anyhow::Context;
+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,
+) -> anyhow::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 slash to the root to ensure the path is valid.
+    root.push('/');
+
+    // 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);
+
+    // BLS is now detected, generate a configuration for it.
+    let generator = BlsConfiguration {
+        entry: EntryDeclaration {
+            title: "$title".to_string(),
+            actions: vec![chainload_action_name.clone()],
+            ..Default::default()
+        },
+        path: format!("{}\\loader", root),
+    };
+
+    // Generate a unique name for the BLS generator and insert the generator into the configuration.
+    config.generators.insert(
+        format!("autoconfigure-bls-{}", root),
+        GeneratorDeclaration {
+            bls: Some(generator),
+            ..Default::default()
+        },
+    );
+
+    // Generate a chainload configuration for BLS.
+    // BLS will provide these values to us.
+    let chainload = ChainloadConfiguration {
+        path: format!("{}\\$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)
+}