Added commands for managing disks

src/backing.c

@@ -49,7 +49,7 @@ Status GetBackingPoolPath(char** _backing_pool_path) {
 	return Format(_backing_pool_path, "/var/lib/sandbox/backings");
 }
 
-Status GetBackingDiskPath(const char* backing_identifier, char** _backing_path) {
+Status GetBackingPath(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);
@@ -72,7 +72,7 @@ Status GetBackingDiskPath(const char* backing_identifier, char** _backing_path)
 Status DoesBackingExist(const char* backing_identifier, bool* _result) {
 	// Get the backing path
 	char* backing_path = NULL;
-	Status status = GetBackingDiskPath(backing_identifier, &backing_path);
+	Status status = GetBackingPath(backing_identifier, &backing_path);
 	if (status != SUCCESS)
 		return status;
 
@@ -83,3 +83,116 @@ Status DoesBackingExist(const char* backing_identifier, bool* _result) {
 
 	return SUCCESS;
 }
+
+Status ListBackings(char*** _backings) {
+	*_backings = NULL;
+
+	// Open the backing pool directory
+	char* backing_pool_path = NULL;
+	Status status = GetBackingPoolPath(&backing_pool_path);
+	if (status != SUCCESS)
+		return status;
+
+	DIR* dir = opendir(backing_pool_path);
+	if (dir == NULL) {
+		Log(LOG_LEVEL_ERROR, "Failed to open the backing pool directory %s (%s).", backing_pool_path, strerror(errno));
+		free(backing_pool_path);
+		return FAILURE;
+	}
+	free(backing_pool_path);
+
+	// Allocate memory for at least one backing (the NULL terminator)
+	*_backings = malloc(sizeof(char*));
+	if (*_backings == NULL) {
+		Log(LOG_LEVEL_ERROR, "Failed to allocate memory for the backings list (%s).", strerror(errno));
+		closedir(dir);
+		return FAILURE;
+	}
+	(*_backings)[0] = NULL;
+
+	// Read the files in the backing pool directory
+	size_t count = 0;
+	struct dirent* file;
+	while ((file = readdir(dir)) != NULL) {
+		if (strcmp(file->d_name, ".") == 0 || strcmp(file->d_name, "..") == 0)
+			continue;
+
+		// Check if the backing exists (this checks for validity)
+		bool exists;
+		Status status = DoesBackingExist(file->d_name, &exists);
+		if (status != SUCCESS || !exists)
+			continue;
+
+		// Allocate memory for the new backing list
+		char** new_backings = realloc(*_backings, (count + 2) * sizeof(char*)); // +2 for the new entry and the NULL terminator
+		if (new_backings == NULL) {
+			Log(LOG_LEVEL_ERROR, "Failed to reallocate memory for the backing list (%s).", strerror(errno));
+			closedir(dir);
+
+			for (size_t i = 0; i < count; i++)
+				free((*_backings)[i]);
+			free(*_backings);
+
+			return FAILURE;
+		}
+		*_backings = new_backings;
+
+		// Duplicate the file name and add it to the list
+		(*_backings)[count] = strdup(file->d_name);
+		if ((*_backings)[count] == NULL) {
+			Log(LOG_LEVEL_ERROR, "Failed to duplicate the backing name (%s).", strerror(errno));
+			closedir(dir);
+
+			for (size_t i = 0; i < count; i++)
+				free((*_backings)[i]);
+			free(*_backings);
+
+			return FAILURE;
+		}
+
+		// Add the NULL terminator
+		(*_backings)[count + 1] = NULL;
+		count++;
+	}
+
+	closedir(dir);
+
+	return SUCCESS;
+}
+
+Status GetLatestBacking(char** _backing_identifier) {
+	// List the backings
+	char** backings = NULL;
+	Status status = ListBackings(&backings);
+	if (status != SUCCESS)
+		return status;
+
+	// Find the latest backing
+	int latest_identifier_index = -1;
+	int latest_index = -1;
+	for (int i = 0; backings[i] != NULL; i++) {
+		int index = GetBackingIndex(backings[i]);
+		if (index > latest_index) {
+			latest_identifier_index = i;
+			latest_index = index;
+		}
+	}
+
+	// Return the latest backing
+	if (latest_identifier_index == -1) {
+		*_backing_identifier = NULL;
+	} else {
+		*_backing_identifier = strdup(backings[latest_identifier_index]);
+		if (*_backing_identifier == NULL) {
+			Log(LOG_LEVEL_ERROR, "Failed to duplicate the backing identifier (%s).", strerror(errno));
+			status = FAILURE;
+		}
+	}
+
+	// Free the backings list
+	for (int i = 0; backings[i] != NULL; i++)
+		free(backings[i]);
+	free(backings);
+
+	return status;
+}