Started implementing backing managment

src/backing.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include "utils.h"
+#include "disk.h"
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#define BACKING_POOL_DIR "/var/lib/sandbox/backings"
+#define MAX_BACKING_LENGTH 256
+
+/// @brief Checks whether the given backing id is valid.
+/// @param backing_id The backing id to check.
+/// @return True if the backing id is valid, false otherwise.
+bool is_valid_backing_id(const char* backing_id);
+
+/// @brief Gets the path of the given backing.
+/// @param backing_id The backing id.
+/// @param out_path The pointer to the output path string. The caller is responsible for freeing the memory.
+/// @return The result of the operation.
+Result get_backing_path(const char* backing_id, char** out_path);
+
+/// @brief Checks whether the given backing exists in the pool.
+/// @param backing_id The backing id.
+/// @param out_exists The pointer to the output boolean.
+/// @return The result of the operation.
+Result backing_exists(const char* backing_id, bool* out_exists);