diff --git a/src/backing.h b/src/backing.h
index 73dbaa2..a829bda 100644
--- a/src/backing.h
+++ b/src/backing.h
@@ -4,3 +4,36 @@
 #include <stdint.h>
 
 #define BACKING_POOL "/var/lib/sandbox/backings"
+
+/// @brief Checks whether the backing pool exists and is a directory.
+/// @return True if the backing pool exists and is a directory, false otherwise.
+bool check_backing_pool(void);
+
+/// @brief Checks whether the backing disk id is valid.
+/// @param backing_id The backing disk id to check.
+/// @return True if the backing disk id is valid, false otherwise.
+bool is_backing_id_valid(const char* backing_id);
+
+/// @brief Checks whether the backing disk exists.
+/// @param backing_id The backing disk id to check.
+/// @return True if the backing disk exists, false otherwise.
+bool backing_exists(const char* backing_id);
+
+/// @brief Adds a backing disk to the backing pool.
+/// @param backing_id The backing disk id to add.
+/// @param entry_id The entry from which the backing disk should be added.
+/// @return True if the backing disk was added, false otherwise.
+bool add_backing(const char* backing_id, const char* entry_id);
+
+/// @brief Removes a backing disk from the backing pool, as well as any backing disks that depend on it.
+/// @param backing_id The backing disk id to remove.
+/// @return True if the backing disk was removed, false otherwise.
+bool remove_backing(const char* backing_id);
+
+/// @brief Lists all backing disks in the backing pool.
+/// @return An array of backing disk ids or NULL if an error occurred. The result must be freed with free(), as well as each individual backing disk id.
+char** list_backings(void);
+
+/// @brief Clears all backing disks from the backing pool.
+/// @return True if all backing disks were removed, false otherwise.
+bool clear_backings(void);
diff --git a/src/sandbox.c b/src/sandbox.c
index 41b2aac..b870572 100644
--- a/src/sandbox.c
+++ b/src/sandbox.c
@@ -22,6 +22,8 @@ int main(int argc, char* argv[]) {
 
 	int consumed = 2;
 
+	// TODO: Implement log level parameter
+
 	switch (command->id) {
 	case CMD_HELP:
 		return cmd_help(argc - consumed, argv + consumed);
diff --git a/src/utils.c b/src/utils.c
index 46c170e..58f6b59 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -276,53 +276,3 @@ char* read_file(int fd) {
 
 	return data;
 }
-
-bool copy_file(const char* src, const char* dst, mode_t mode) {
-	// Open the source file
-	int src_fd = open(src, O_RDONLY);
-	if (src_fd == -1) {
-		log_message(LOG_ERROR, "Failed to open the source file %s (%s).", src, strerror(errno));
-		return false;
-	}
-
-	// Open the destination file
-	int dst_fd = open(dst, O_WRONLY | O_CREAT | O_TRUNC, mode);
-	if (dst_fd == -1) {
-		log_message(LOG_ERROR, "Failed to open the destination file %s (%s).", dst, strerror(errno));
-
-		close(src_fd);
-
-		return false;
-	}
-
-	// Copy the file
-	char buffer[4096];
-	ssize_t n;
-
-	while ((n = read(src_fd, buffer, sizeof(buffer))) > 0) {
-		if (write(dst_fd, buffer, n) != n) {
-			log_message(LOG_ERROR, "Failed to write to the destination file %s (%s).", dst, strerror(errno));
-
-			close(src_fd);
-			close(dst_fd);
-
-			return false;
-		}
-	}
-
-	// Check for read errors
-	if (n < 0) {
-		log_message(LOG_ERROR, "Failed to read the source file %s (%s).", src, strerror(errno));
-
-		close(src_fd);
-		close(dst_fd);
-
-		return false;
-	}
-
-	// Close the files
-	close(src_fd);
-	close(dst_fd);
-
-	return true;
-}
diff --git a/src/utils.h b/src/utils.h
index 2349b31..4660e44 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -11,12 +11,27 @@ typedef enum {
 	LOG_ERROR,
 } LogLevel;
 
+/// @brief Formats a string using printf-style formatting.
+/// @param fmt The format string.
+/// @param ... The arguments to format into the string.
+/// @return The formatted string or NULL if an error occurred. The result must be freed with free().
 char* format(const char* fmt, ...);
 
+/// @brief Logs a message to the console.
+/// @param level The log level of the message.
+/// @param fmt The format string of the message.
+/// @param ... The arguments to format into the message.
 void log_message(LogLevel level, const char* fmt, ...);
 
+/// @brief Executes a command and returns the exit code as well as the output and error streams.
+/// @param outb The output stream of the command. May be NULL if the output is not needed.
+/// @param errb The error stream of the command. May be NULL if the error is not needed.
+/// @param file The file to execute.
+/// @param ... The arguments to pass to the file.
+/// @return The exit code of the command.
 int execute(char** outb, char** errb, const char* file, ...);
 
-char* read_file(int fd);
-
-bool copy_file(const char* src, const char* dst, mode_t mode);
+/// @brief Reads the contents of a file into a string. The result might contain null bytes.
+/// @param fd The file descriptor of the file to read.
+/// @return The contents of the file or NULL if an error occurred. The result must be freed with free().
+char* read_file(int fd);
\ No newline at end of file