Added add-backing and remove-backing commands (still missing recursive remove)

src/backing.c

@@ -84,6 +84,124 @@ Status DoesBackingExist(const char* backing_identifier, bool* _result) {
 	return SUCCESS;
 }
 
+Status AddBacking(const char* backing_identifier, const char* entry_identifier) {
+	// Check that the backing does not already exist
+	bool exists;
+	Status status = DoesBackingExist(backing_identifier, &exists);
+	if (status != SUCCESS)
+		return status;
+
+	if (exists) {
+		Log(LOG_LEVEL_ERROR, "The backing '%s' already exists.", backing_identifier);
+		return FAILURE;
+	}
+
+	// Check that the entry disk exists
+	status = DoesEntryDiskExist(entry_identifier, &exists);
+	if (status != SUCCESS)
+		return status;
+
+	if (!exists) {
+		Log(LOG_LEVEL_ERROR, "The entry disk '%s' does not exist. Cannot create backing from it.", entry_identifier);
+		return FAILURE;
+	}
+
+	// Get information about the entry disk
+	DiskInfo entry_info;
+	status = GetEntryDiskInfo(entry_identifier, &entry_info);
+	if (status != SUCCESS)
+		return status;
+
+	// Check that the backing used by the entry actually exists (broken backing chain)
+	if (entry_info.backing_identifier != NULL) {
+		status = DoesBackingExist(entry_info.backing_identifier, &exists);
+		if (status != SUCCESS) {
+			FreeDiskInfo(&entry_info);
+			return status;
+		}
+
+		if (!exists) {
+			Log(LOG_LEVEL_ERROR, "The backing '%s' of the entry disk '%s' does not exist.", entry_info.backing_identifier, entry_identifier);
+
+			FreeDiskInfo(&entry_info);
+			return FAILURE;
+		}
+	}
+
+	// Copy the entry disk to the backing disk
+	char* entry_disk_path = NULL;
+	status = GetEntryDiskPath(entry_identifier, &entry_disk_path);
+	if (status != SUCCESS) {
+		FreeDiskInfo(&entry_info);
+		return status;
+	}
+
+	char* backing_path = NULL;
+	status = GetBackingPath(backing_identifier, &backing_path);
+	if (status != SUCCESS) {
+		free(entry_disk_path);
+		FreeDiskInfo(&entry_info);
+		return status;
+	}
+
+	status = CopyFile(entry_disk_path, backing_path);
+	if (status != SUCCESS) {
+		free(entry_disk_path);
+		free(backing_path);
+		FreeDiskInfo(&entry_info);
+		return status;
+	}
+
+	free(entry_disk_path);
+
+	// If the entry disk has a backing, rebase the backing to the new backing
+	if (entry_info.backing_identifier != NULL) {
+		status = RebaseDisk(backing_path, entry_info.backing_identifier);
+		if (status != SUCCESS) {
+			RemoveBacking(backing_identifier);
+
+			free(backing_path);
+			FreeDiskInfo(&entry_info);
+			return status;
+		}
+	}
+
+	free(backing_path);
+	FreeDiskInfo(&entry_info);
+	return SUCCESS;
+}
+
+Status RemoveBacking(const char* backing_identifier) {
+	// Check that the backing exists
+	bool exists;
+	Status status = DoesBackingExist(backing_identifier, &exists);
+	if (status != SUCCESS)
+		return status;
+
+	if (!exists) {
+		Log(LOG_LEVEL_ERROR, "The backing '%s' does not exist.", backing_identifier);
+		return FAILURE;
+	}
+
+	// Get the backing path
+	char* backing_path = NULL;
+	status = GetBackingPath(backing_identifier, &backing_path);
+	if (status != SUCCESS)
+		return status;
+
+	// Remove the backing
+	if (unlink(backing_path) != 0) {
+		Log(LOG_LEVEL_ERROR, "Failed to remove the backing '%s' (%s).", backing_identifier, strerror(errno));
+		free(backing_path);
+		return FAILURE;
+	}
+	free(backing_path);
+
+	// TODO: Remove all the backings that use this backing as a base
+
+	return SUCCESS;
+}
+
 Status ListBackings(char*** _backings) {
 	*_backings = NULL;