Added add_backing

src/backing.c

@@ -9,6 +9,7 @@
 #include <string.h>
 #include <errno.h>
 #include <unistd.h>
+#include <libgen.h>
 #include <sys/stat.h>
 
 result_t check_backing_identifier(const char* backing) {
@@ -69,10 +70,16 @@ result_t check_backing_exists(const char* backing) {
 }
 
 result_t get_backing_pool_path(char** _path) {
+	// Initialize the output parameters
+	*_path = NULL;
+
 	return format(_path, "/var/lib/sandbox/backings");
 }
 
 result_t get_backing_path(char** _path, const char* backing) {
+	// Initialize the output parameters
+	*_path = NULL;
+
 	// Check the backing identifier
 	result_t result = check_backing_identifier(backing);
 	if (result != success())
@@ -92,6 +99,9 @@ result_t get_backing_path(char** _path, const char* backing) {
 }
 
 result_t get_backing_default_path(char** _path) {
+	// Initialize the output parameters
+	*_path = NULL;
+
 	// Get the backing pool path
 	char* pool_path;
 	result_t result = get_backing_pool_path(&pool_path);
@@ -105,6 +115,148 @@ result_t get_backing_default_path(char** _path) {
 	return result;
 }
 
+result_t get_backing_temp_path(char** _path) {
+	// Initialize the output parameters
+	*_path = NULL;
+
+	// Get the backing pool path
+	char* pool_path;
+	result_t result = get_backing_pool_path(&pool_path);
+	if (result != success())
+		return result;
+
+	// Format the backing path
+	result = format(_path, "%s/temp", pool_path);
+
+	free(pool_path);
+	return result;
+}
+
+result_t add_backing(char** _backing, const char* container) {
+	// Initialize the output parameters
+	*_backing = NULL;
+
+	// Get the container path
+	char* path;
+	result_t result = get_container_path(&path, container);
+	if (result != success())
+		return result;
+
+	// Import the container as a backing
+	result = import_backing(_backing, path);
+
+	free(path);
+	return result;
+}
+
+result_t import_backing(char** _backing, const char* path) {
+	// Initialize the output parameters
+	*_backing = NULL;
+
+	// Get the temporary backing path
+	char* temp_path;
+	result_t result = get_backing_temp_path(&temp_path);
+	if (result != success())
+		return result;
+
+	// Copy the disk to the temporary backing path
+	result = copy_file(path, temp_path);
+	if (result != success()) {
+		free(temp_path);
+		return result;
+	}
+
+	// Get the disk info to know if the disk is backed
+	disk_info_t info;
+	result = get_disk_info(&info, temp_path);
+	if (result != success()) {
+		remove(temp_path);
+		free(temp_path);
+		return result;
+	}
+
+	if (info.backing_path != NULL) {
+		// Get the backing identifier of the parent
+		char* backing = strdup(basename(info.backing_path));
+		if (backing == NULL) {
+			free_disk_info(&info);
+			remove(temp_path);
+			free(temp_path);
+			return failure("Failed to get the backing identifier of the parent.");
+		}
+
+		// Check that the backing exists
+		result = check_backing_exists(backing);
+		if (result != success()) {
+			free_disk_info(&info);
+			remove(temp_path);
+			free(temp_path);
+			free(backing);
+			return result;
+		}
+
+		// Reback the disk to the parent
+		result = reback_disk(temp_path, backing);
+		if (result != success()) {
+			free_disk_info(&info);
+			remove(temp_path);
+			free(temp_path);
+			free(backing);
+			return result;
+		}
+
+		free(backing);
+	}
+
+	free_disk_info(&info);
+
+	// Get the md5 hash of the disk as the backing identifier
+	char* backing;
+	result = md5sum(&backing, temp_path);
+	if (result != success()) {
+		remove(temp_path);
+		free(temp_path);
+		return result;
+	}
+
+	// Check if the backing already exists
+	result = check_backing_exists(backing);
+	if (result == success()) {
+		result = failure("Backing '%s' already exists.", backing);
+		free(backing);
+		remove(temp_path);
+		free(temp_path);
+		return result;
+	}
+
+	// Get the path of the final backing
+	char* backing_path;
+	result = get_backing_path(&backing_path, backing);
+	if (result != success()) {
+		free(backing);
+		remove(temp_path);
+		free(temp_path);
+		return result;
+	}
+
+	// Move the temporary backing to the final backing path
+	errno = 0;
+	if (rename(temp_path, backing_path) != 0) {
+		result = failure("Failed to move the temporary backing to the final backing path (%s).", strerror(errno));
+		free(backing);
+		free(backing_path);
+		remove(temp_path);
+		free(temp_path);
+		return result;
+	}
+
+	free(backing_path);
+	free(temp_path);
+
+	*_backing = backing;
+	return result;
+}
+
 result_t remove_backing(const char* backing) {
 	// Check that the backing exists
 	result_t result = check_backing_exists(backing);
@@ -137,6 +289,9 @@ bool backing_filter(const char* file) {
 }
 
 result_t list_backings(char*** _backings) {
+	// Initialize the output parameters
+	*_backings = NULL;
+
 	// Get the backing pool path
 	char* pool_path;
 	result_t result = get_backing_pool_path(&pool_path);
@@ -151,6 +306,9 @@ result_t list_backings(char*** _backings) {
 }
 
 result_t get_default_backing(char** _backing) {
+	// Initialize the output parameters
+	*_backing = NULL;
+
 	// Get the backing default path
 	char* path;
 	result_t result = get_backing_default_path(&path);