fix: Allow jailer to continue with partial CPU cache info

Signed-off-by: Gudmundur Bjarni Olafsson <[email protected]>

Author: gudmundur

src/jailer/src/env.rs

@@ -555,6 +555,8 @@ impl Env {
             .map_err(|err| JailerError::CreateDir(jailer_cache_dir.to_owned(), err))?;
 
         for index in 0..(MAX_CACHE_LEVEL + 1) {
+            let mut err_str = String::new();
+
             let index_folder = format!("index{}", index);
             let host_path = PathBuf::from(HOST_CACHE_INFO).join(&index_folder);
 
@@ -575,17 +577,35 @@ impl Env {
                 let host_cache_file = host_path.join(entry);
                 let jailer_cache_file = jailer_path.join(entry);
 
-                let line = readln_special(&host_cache_file)?;
-                writeln_special(&jailer_cache_file, line)?;
+                if let Ok(line) = readln_special(&host_cache_file) {
+                    writeln_special(&jailer_cache_file, line)?;
+
+                    // We now change the permissions.
+                    let dest_path_cstr = to_cstring(&jailer_cache_file)?;
+                    // SAFETY: Safe because dest_path_cstr is null-terminated.
+                    SyscallReturnCode(unsafe {
+                        libc::chown(dest_path_cstr.as_ptr(), self.uid(), self.gid())
+                    })
+                    .into_empty_result()
+                    .map_err(|err| {
+                        JailerError::ChangeFileOwner(jailer_cache_file.to_owned(), err)
+                    })?;
+                } else {
+                    err_str += entry;
+                    err_str += ", ";
+                }
+            }
+
+            // Pop the last 2 chars if a comma and space are present.
+            // The unwrap is safe since we check that the string actually
+            // ends with those 2 chars.
+            if err_str.ends_with(", ") {
+                err_str.pop().unwrap();
+                err_str.pop().unwrap();
+            }
 
-                // We now change the permissions.
-                let dest_path_cstr = to_cstring(&jailer_cache_file)?;
-                // SAFETY: Safe because dest_path_cstr is null-terminated.
-                SyscallReturnCode(unsafe {
-                    libc::chown(dest_path_cstr.as_ptr(), self.uid(), self.gid())
-                })
-                .into_empty_result()
-                .map_err(|err| JailerError::ChangeFileOwner(jailer_cache_file.to_owned(), err))?;
+            if !err_str.is_empty() {
+                println!("Could not read the {err_str} for cache level {index}.");
             }
         }
         Ok(())