parsers/bls: BLS config for UKI

Johan-Liebert1 · Johan-Liebert1 · commit e58f7eab1ed9 · 2025-09-23T19:04:45.000+05:30
This is in prep for adding config files for BLS compliant bootloaders
booting via UKI.

Adds a field `cfg_type` to BLSConfig which will contain either of the
following sets of keys:

cfg_type - NonEFI

- linux
- initrd
- options

or

cfg_type - EFI

- efi

Signed-off-by: Pragyan Poudyal &lt;pragyanpoudyal41999@gmail.com&gt;
diff --git a/crates/lib/src/bootc_composefs/boot.rs b/crates/lib/src/bootc_composefs/boot.rs
@@ -35,7 +35,7 @@ use serde::{Deserialize, Serialize};
 use crate::bootc_composefs::repo::open_composefs_repo;
 use crate::bootc_composefs::state::{get_booted_bls, write_composefs_state};
 use crate::bootc_composefs::status::get_sorted_uki_boot_entries;
-use crate::parsers::bls_config::BLSConfig;
+use crate::parsers::bls_config::{BLSConfig, BLSConfigType};
 use crate::parsers::grub_menuconfig::MenuEntry;
 use crate::spec::ImageReference;
 use crate::task::Task;
@@ -448,25 +448,31 @@ pub(crate) fn setup_composefs_bls_boot(
                 .with_title(title)
                 .with_sort_key(default_sort_key.into())
                 .with_version(version)
-                .with_linux(format!(
-                    "/{}/{id_hex}/vmlinuz",
-                    entry_paths.abs_entries_path
-                ))
-                .with_initrd(vec![format!(
-                    "/{}/{id_hex}/initrd",
-                    entry_paths.abs_entries_path
-                )])
-                .with_options(cmdline_refs);
+                .with_cfg(BLSConfigType::NonEFI {
+                    linux: format!("/{}/{id_hex}/vmlinuz", entry_paths.abs_entries_path),
+                    initrd: vec![format!("/{}/{id_hex}/initrd", entry_paths.abs_entries_path)],
+                    options: Some(cmdline_refs),
+                });
 
             match find_vmlinuz_initrd_duplicates(&boot_digest)? {
                 Some(symlink_to) => {
-                    bls_config.linux =
-                        format!("/{}/{symlink_to}/vmlinuz", entry_paths.abs_entries_path);
-
-                    bls_config.initrd = vec![format!(
-                        "/{}/{symlink_to}/initrd",
-                        entry_paths.abs_entries_path
-                    )];
+                    match bls_config.cfg_type {
+                        BLSConfigType::NonEFI {
+                            ref mut linux,
+                            ref mut initrd,
+                            ..
+                        } => {
+                            *linux =
+                                format!("/{}/{symlink_to}/vmlinuz", entry_paths.abs_entries_path);
+
+                            *initrd = vec![format!(
+                                "/{}/{symlink_to}/initrd",
+                                entry_paths.abs_entries_path
+                            )];
+                        }
+
+                        _ => unreachable!(),
+                    };
                 }
 
                 None => {
diff --git a/crates/lib/src/bootc_composefs/state.rs b/crates/lib/src/bootc_composefs/state.rs
@@ -17,6 +17,7 @@ use rustix::{
 };
 
 use crate::bootc_composefs::boot::BootType;
+use crate::parsers::bls_config::BLSConfigType;
 use crate::{
     composefs_consts::{
         COMPOSEFS_CMDLINE, COMPOSEFS_STAGED_DEPLOYMENT_FNAME, COMPOSEFS_TRANSIENT_STATE_DIR,
@@ -43,14 +44,31 @@ pub(crate) fn get_booted_bls() -> Result<BLSConfig> {
 
         let bls = parse_bls_config(&std::fs::read_to_string(&entry.path())?)?;
 
-        let Some(opts) = &bls.options else {
-            anyhow::bail!("options not found in bls config")
-        };
-        let opts = Cmdline::from(opts);
+        match &bls.cfg_type {
+            BLSConfigType::EFI { efi } => {
+                let composfs_param_value = booted.value().ok_or(anyhow::anyhow!(
+                    "Failed to get composefs kernel cmdline value"
+                ))?;
 
-        if opts.iter().any(|v| v == booted) {
-            return Ok(bls);
-        }
+                if efi.contains(composfs_param_value) {
+                    return Ok(bls);
+                }
+            }
+
+            BLSConfigType::NonEFI { options, .. } => {
+                let Some(opts) = options else {
+                    anyhow::bail!("options not found in bls config")
+                };
+
+                let opts = Cmdline::from(opts);
+
+                if opts.iter().any(|v| v == booted) {
+                    return Ok(bls);
+                }
+            }
+
+            BLSConfigType::Unknown => anyhow::bail!("Unknown BLS Config type"),
+        };
     }
 
     Err(anyhow::anyhow!("Booted BLS not found"))
diff --git a/crates/lib/src/bootc_composefs/status.rs b/crates/lib/src/bootc_composefs/status.rs
@@ -9,7 +9,7 @@ use crate::{
     bootc_composefs::boot::{get_esp_partition, get_sysroot_parent_dev, BootType},
     composefs_consts::{BOOT_LOADER_ENTRIES, COMPOSEFS_CMDLINE, USER_CFG},
     parsers::{
-        bls_config::{parse_bls_config, BLSConfig},
+        bls_config::{parse_bls_config, BLSConfig, BLSConfigType},
         grub_menuconfig::{parse_grub_menuentry_file, MenuEntry},
     },
     spec::{BootEntry, BootOrder, Host, HostSpec, ImageReference, ImageStatus},
@@ -360,13 +360,25 @@ pub(crate) async fn composefs_deployment_status() -> Result<Host> {
 
     match boot_type {
         BootType::Bls => {
-            host.status.rollback_queued = !get_sorted_bls_boot_entries(&boot_dir, false)?
+            let bls_config = get_sorted_bls_boot_entries(&boot_dir, false)?;
+            let bls_config = bls_config
                 .first()
-                .ok_or(anyhow::anyhow!("First boot entry not found"))?
-                .options
-                .as_ref()
-                .ok_or(anyhow::anyhow!("options key not found in bls config"))?
-                .contains(composefs_digest.as_ref());
+                .ok_or(anyhow::anyhow!("First boot entry not found"))?;
+
+            match &bls_config.cfg_type {
+                BLSConfigType::EFI { efi } => {
+                    host.status.rollback_queued = efi.contains(composefs_digest.as_ref());
+                }
+
+                BLSConfigType::NonEFI { options, .. } => {
+                    host.status.rollback_queued = !options
+                        .as_ref()
+                        .ok_or(anyhow::anyhow!("options key not found in bls config"))?
+                        .contains(composefs_digest.as_ref());
+                }
+
+                BLSConfigType::Unknown => todo!(),
+            };
         }
 
         BootType::Uki => {
@@ -392,7 +404,7 @@ pub(crate) async fn composefs_deployment_status() -> Result<Host> {
 mod tests {
     use cap_std_ext::{cap_std, dirext::CapStdExtDirExt};
 
-    use crate::parsers::grub_menuconfig::MenuentryBody;
+    use crate::parsers::{bls_config::BLSConfigType, grub_menuconfig::MenuentryBody};
 
     use super::*;
 
@@ -442,16 +454,20 @@ mod tests {
         let mut config1 = BLSConfig::default();
         config1.title = Some("Fedora 42.20250623.3.1 (CoreOS)".into());
         config1.sort_key = Some("1".into());
-        config1.linux = "/boot/7e11ac46e3e022053e7226a20104ac656bf72d1a84e3a398b7cce70e9df188b6/vmlinuz-5.14.10".into();
-        config1.initrd = vec!["/boot/7e11ac46e3e022053e7226a20104ac656bf72d1a84e3a398b7cce70e9df188b6/initramfs-5.14.10.img".into()];
-        config1.options = Some("root=UUID=abc123 rw composefs=7e11ac46e3e022053e7226a20104ac656bf72d1a84e3a398b7cce70e9df188b6".into());
+        config1.cfg_type = BLSConfigType::NonEFI {
+            linux: "/boot/7e11ac46e3e022053e7226a20104ac656bf72d1a84e3a398b7cce70e9df188b6/vmlinuz-5.14.10".into(),
+            initrd: vec!["/boot/7e11ac46e3e022053e7226a20104ac656bf72d1a84e3a398b7cce70e9df188b6/initramfs-5.14.10.img".into()],
+            options: Some("root=UUID=abc123 rw composefs=7e11ac46e3e022053e7226a20104ac656bf72d1a84e3a398b7cce70e9df188b6".into()),
+        };
 
         let mut config2 = BLSConfig::default();
         config2.title = Some("Fedora 41.20250214.2.0 (CoreOS)".into());
         config2.sort_key = Some("2".into());
-        config2.linux = "/boot/febdf62805de2ae7b6b597f2a9775d9c8a753ba1e5f09298fc8fbe0b0d13bf01/vmlinuz-5.14.10".into();
-        config2.initrd = vec!["/boot/febdf62805de2ae7b6b597f2a9775d9c8a753ba1e5f09298fc8fbe0b0d13bf01/initramfs-5.14.10.img".into()];
-        config2.options = Some("root=UUID=abc123 rw composefs=febdf62805de2ae7b6b597f2a9775d9c8a753ba1e5f09298fc8fbe0b0d13bf01".into());
+        config2.cfg_type = BLSConfigType::NonEFI {
+            linux: "/boot/febdf62805de2ae7b6b597f2a9775d9c8a753ba1e5f09298fc8fbe0b0d13bf01/vmlinuz-5.14.10".into(),
+            initrd: vec!["/boot/febdf62805de2ae7b6b597f2a9775d9c8a753ba1e5f09298fc8fbe0b0d13bf01/initramfs-5.14.10.img".into()],
+            options: Some("root=UUID=abc123 rw composefs=febdf62805de2ae7b6b597f2a9775d9c8a753ba1e5f09298fc8fbe0b0d13bf01".into())
+        };
 
         assert_eq!(result[0].sort_key.as_ref().unwrap(), "1");
         assert_eq!(result[1].sort_key.as_ref().unwrap(), "2");
diff --git a/crates/lib/src/parsers/bls_config.rs b/crates/lib/src/parsers/bls_config.rs
@@ -5,10 +5,29 @@
 #![allow(dead_code)]
 
 use anyhow::{anyhow, Result};
+use core::fmt;
 use std::collections::HashMap;
 use std::fmt::Display;
 use uapi_version::Version;
 
+#[derive(Debug, PartialEq, PartialOrd, Eq, Default)]
+pub enum BLSConfigType {
+    EFI {
+        /// The path to the EFI binary, usually a UKI
+        efi: String,
+    },
+    NonEFI {
+        /// The path to the linux kernel to boot.
+        linux: String,
+        /// The paths to the initrd images.
+        initrd: Vec<String>,
+        /// Kernel command line options.
+        options: Option<String>,
+    },
+    #[default]
+    Unknown,
+}
+
 /// Represents a single Boot Loader Specification config file.
 ///
 /// The boot loader should present the available boot menu entries to the user in a sorted list.
@@ -24,12 +43,9 @@ pub(crate) struct BLSConfig {
     ///
     /// This is hidden and must be accessed via [`Self::version()`];
     version: String,
-    /// The path to the linux kernel to boot.
-    pub(crate) linux: String,
-    /// The paths to the initrd images.
-    pub(crate) initrd: Vec<String>,
-    /// Kernel command line options.
-    pub(crate) options: Option<String>,
+
+    pub(crate) cfg_type: BLSConfigType,
+
     /// The machine ID of the OS.
     pub(crate) machine_id: Option<String>,
     /// The sort key for the boot menu.
@@ -79,13 +95,30 @@ impl Display for BLSConfig {
         }
 
         writeln!(f, "version {}", self.version)?;
-        writeln!(f, "linux {}", self.linux)?;
-        for initrd in self.initrd.iter() {
-            writeln!(f, "initrd {}", initrd)?;
-        }
-        if let Some(options) = self.options.as_deref() {
-            writeln!(f, "options {}", options)?;
+
+        match &self.cfg_type {
+            BLSConfigType::EFI { efi } => {
+                writeln!(f, "efi {}", efi)?;
+            }
+
+            BLSConfigType::NonEFI {
+                linux,
+                initrd,
+                options,
+            } => {
+                writeln!(f, "linux {}", linux)?;
+                for initrd in initrd.iter() {
+                    writeln!(f, "initrd {}", initrd)?;
+                }
+
+                if let Some(options) = options.as_deref() {
+                    writeln!(f, "options {}", options)?;
+                }
+            }
+
+            BLSConfigType::Unknown => return Err(fmt::Error),
         }
+
         if let Some(machine_id) = self.machine_id.as_deref() {
             writeln!(f, "machine-id {}", machine_id)?;
         }
@@ -114,16 +147,8 @@ impl BLSConfig {
         self.version = new_val;
         self
     }
-    pub(crate) fn with_linux(&mut self, new_val: String) -> &mut Self {
-        self.linux = new_val;
-        self
-    }
-    pub(crate) fn with_initrd(&mut self, new_val: Vec<String>) -> &mut Self {
-        self.initrd = new_val;
-        self
-    }
-    pub(crate) fn with_options(&mut self, new_val: String) -> &mut Self {
-        self.options = Some(new_val);
+    pub(crate) fn with_cfg(&mut self, config: BLSConfigType) -> &mut Self {
+        self.cfg_type = config;
         self
     }
     #[allow(dead_code)]
@@ -146,6 +171,7 @@ pub(crate) fn parse_bls_config(input: &str) -> Result<BLSConfig> {
     let mut title = None;
     let mut version = None;
     let mut linux = None;
+    let mut efi = None;
     let mut initrd = Vec::new();
     let mut options = None;
     let mut machine_id = None;
@@ -168,22 +194,35 @@ pub(crate) fn parse_bls_config(input: &str) -> Result<BLSConfig> {
                 "options" => options = Some(value),
                 "machine-id" => machine_id = Some(value),
                 "sort-key" => sort_key = Some(value),
+                "efi" => efi = Some(value),
                 _ => {
                     extra.insert(key.to_string(), value);
                 }
             }
         }
     }
 
-    let linux = linux.ok_or_else(|| anyhow!("Missing 'linux' value"))?;
     let version = version.ok_or_else(|| anyhow!("Missing 'version' value"))?;
 
+    let cfg_type = match (linux, efi) {
+        (None, Some(efi)) => BLSConfigType::EFI { efi },
+
+        (Some(linux), None) => BLSConfigType::NonEFI {
+            linux,
+            initrd,
+            options,
+        },
+
+        // The spec makes no mention of whether both can be present or not
+        // Fow now, for us, we won't have both at the same time
+        (Some(_), Some(_)) => anyhow::bail!("'linux' and 'efi' values present"),
+        (None, None) => anyhow::bail!("Missing 'linux' or 'efi' value"),
+    };
+
     Ok(BLSConfig {
         title,
         version,
-        linux,
-        initrd,
-        options,
+        cfg_type,
         machine_id,
         sort_key,
         extra,
@@ -208,14 +247,23 @@ mod tests {
 
         let config = parse_bls_config(input)?;
 
+        let BLSConfigType::NonEFI {
+            linux,
+            initrd,
+            options,
+        } = config.cfg_type
+        else {
+            panic!("Expected non EFI variant");
+        };
+
         assert_eq!(
             config.title,
             Some("Fedora 42.20250623.3.1 (CoreOS)".to_string())
         );
         assert_eq!(config.version, "2");
-        assert_eq!(config.linux, "/boot/7e11ac46e3e022053e7226a20104ac656bf72d1a84e3a398b7cce70e9df188b6/vmlinuz-5.14.10");
-        assert_eq!(config.initrd, vec!["/boot/7e11ac46e3e022053e7226a20104ac656bf72d1a84e3a398b7cce70e9df188b6/initramfs-5.14.10.img"]);
-        assert_eq!(config.options, Some("root=UUID=abc123 rw composefs=7e11ac46e3e022053e7226a20104ac656bf72d1a84e3a398b7cce70e9df188b6".to_string()));
+        assert_eq!(linux, "/boot/7e11ac46e3e022053e7226a20104ac656bf72d1a84e3a398b7cce70e9df188b6/vmlinuz-5.14.10");
+        assert_eq!(initrd, vec!["/boot/7e11ac46e3e022053e7226a20104ac656bf72d1a84e3a398b7cce70e9df188b6/initramfs-5.14.10.img"]);
+        assert_eq!(options, Some("root=UUID=abc123 rw composefs=7e11ac46e3e022053e7226a20104ac656bf72d1a84e3a398b7cce70e9df188b6".to_string()));
         assert_eq!(config.extra.get("custom1"), Some(&"value1".to_string()));
         assert_eq!(config.extra.get("custom2"), Some(&"value2".to_string()));
 
@@ -235,8 +283,12 @@ mod tests {
 
         let config = parse_bls_config(input)?;
 
+        let BLSConfigType::NonEFI { initrd, .. } = config.cfg_type else {
+            panic!("Expected non EFI variant");
+        };
+
         assert_eq!(
-            config.initrd,
+            initrd,
             vec!["/boot/initramfs-1.img", "/boot/initramfs-2.img"]
         );
 
