keylimectl: Use correct variant for UEFI log parse failures

The measured boot policy generator was using
PolicyGenerationError::Output (which formats as "Failed to write output
to ...") when the UEFI event log could not be read or parsed. This
produced misleading error messages like "Failed to write output to
/sys/kernel/.../binary_bios_measurements" for what is actually a
read/parse error.

Add a dedicated EventLogParse variant and use it in
generate_from_eventlog() and get_eventlog_stats(), producing clear
messages like "Failed to parse event log
/sys/.../binary_bios_measurements: IO error: No such file".

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>

Author: ansasaki

keylimectl/src/commands/error.rs

@@ -156,6 +156,10 @@ pub enum PolicyGenerationError {
     #[error("Unsupported hash algorithm: {algorithm}")]
     UnsupportedAlgorithm { algorithm: String },
 
+    /// Event log parse error
+    #[error("Failed to parse event log {path}: {reason}")]
+    EventLogParse { path: PathBuf, reason: String },
+
     /// Output write error
     #[error("Failed to write output to {path}: {reason}")]
     Output { path: PathBuf, reason: String },

keylimectl/src/policy_tools/measured_boot_gen.rs

@@ -21,16 +21,17 @@ pub fn generate_from_eventlog(
     path: &Path,
     include_secureboot: bool,
 ) -> Result<MeasuredBootPolicy, PolicyGenerationError> {
-    let path_str =
-        path.to_str().ok_or_else(|| PolicyGenerationError::Output {
+    let path_str = path.to_str().ok_or_else(|| {
+        PolicyGenerationError::EventLogParse {
             path: path.to_path_buf(),
             reason: "Invalid path encoding".to_string(),
-        })?;
+        }
+    })?;
 
     let handler = UefiLogHandler::new(path_str).map_err(|e| {
-        PolicyGenerationError::Output {
+        PolicyGenerationError::EventLogParse {
             path: path.to_path_buf(),
-            reason: format!("Failed to parse UEFI event log: {e}"),
+            reason: format!("{e}"),
         }
     })?;
 
@@ -363,16 +364,17 @@ pub struct MeasuredBootStats {
 pub fn get_eventlog_stats(
     path: &Path,
 ) -> Result<MeasuredBootStats, PolicyGenerationError> {
-    let path_str =
-        path.to_str().ok_or_else(|| PolicyGenerationError::Output {
+    let path_str = path.to_str().ok_or_else(|| {
+        PolicyGenerationError::EventLogParse {
             path: path.to_path_buf(),
             reason: "Invalid path encoding".to_string(),
-        })?;
+        }
+    })?;
 
     let handler = UefiLogHandler::new(path_str).map_err(|e| {
-        PolicyGenerationError::Output {
+        PolicyGenerationError::EventLogParse {
             path: path.to_path_buf(),
-            reason: format!("Failed to parse UEFI event log: {e}"),
+            reason: format!("{e}"),
         }
     })?;