Started implementing the backing system

src/backing.c

@@ -0,0 +1,62 @@
+#include "backing.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+bool IsBackingIdentifierValid(const char* backing_identifier) {
+	if (backing_identifier == NULL)
+		return false;
+
+	// Check that the identifier is not empty or too long
+	size_t length = strlen(backing_identifier);
+	if (length == 0 || length > 64)
+		return false;
+
+	// Check that the identifier does not contain any slashes
+	for (size_t i = 0; i < length; i++)
+		if (backing_identifier[i] == '/')
+			return false;
+
+	// Check that the identifier is not "." or ".."
+	if (strcmp(backing_identifier, ".") == 0 || strcmp(backing_identifier, "..") == 0)
+		return false;
+
+	// Check that the identifier starts with a number
+	if (backing_identifier[0] >= '0' && backing_identifier[0] <= '9')
+		return false;
+
+	return true;
+}
+
+int GetBackingIndex(const char* backing_identifier) {
+	// Check that the identifier is valid
+	if (!IsBackingIdentifierValid(backing_identifier))
+		return -1;
+
+	// Get the index
+	return atoi(backing_identifier);
+}
+
+Status GetBackingPoolPath(char** _backing_pool_path) {
+	return Format(_backing_pool_path, "/var/lib/sandbox/backings");
+}
+
+Status GetBackingDiskPath(const char* backing_identifier, char** _backing_path) {
+	// Check that the identifier is valid, as it will be used in a path
+	if (!IsBackingIdentifierValid(backing_identifier)) {
+		Log(LOG_LEVEL_ERROR, "Invalid backing identifier '%s'.", backing_identifier);
+		return FAILURE;
+	}
+
+	// Get the backing pool path
+	char* backing_pool_path = NULL;
+	Status status = GetBackingPoolPath(&backing_pool_path);
+	if (status != SUCCESS)
+		return status;
+
+	// Format the backing path
+	status = Format(_backing_path, "%s/%s", backing_pool_path, backing_identifier);
+	free(backing_pool_path);
+
+	return status;
+}

src/backing.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include "utils.h"
+
+bool IsBackingIdentifierValid(const char* backing_identifier);
+int GetBackingIndex(const char* backing_identifier);
+
+Status GetBackingPoolPath(char** _backing_pool_path);
+Status GetBackingDiskPath(const char* backing_identifier, char** _backing_path);