@@ -483,10 +483,9 @@ void bdrv_get_backing_filename(BlockDriverState *bs,
char *filename, int filename_size);
void bdrv_get_full_backing_filename(BlockDriverState *bs,
char *dest, size_t sz, Error **errp);
-void bdrv_get_full_backing_filename_from_filename(const char *backed,
- const char *backing,
- char *dest, size_t sz,
- Error **errp);
+char *bdrv_get_full_backing_filename_from_filename(const char *backed,
+ const char *backing,
+ Error **errp);
int path_has_protocol(const char *path);
int path_is_absolute(const char *path);
@@ -288,20 +288,28 @@ int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
return 0;
}
-void bdrv_get_full_backing_filename_from_filename(const char *backed,
- const char *backing,
- char *dest, size_t sz,
- Error **errp)
+/* If @backing is empty, this function returns NULL without setting
+ * @errp. In all other cases, NULL will only be returned with @errp
+ * set.
+ *
+ * Therefore, a return value of NULL without @errp set means that
+ * there is no backing file; if @errp is set, there is one but its
+ * absolute filename cannot be generated.
+ */
+char *bdrv_get_full_backing_filename_from_filename(const char *backed,
+ const char *backing,
+ Error **errp)
{
- if (backing[0] == '\0' || path_has_protocol(backing) ||
- path_is_absolute(backing))
- {
- pstrcpy(dest, sz, backing);
+ if (backing[0] == '\0') {
+ return NULL;
+ } else if (path_has_protocol(backing) || path_is_absolute(backing)) {
+ return g_strdup(backing);
} else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) {
error_setg(errp, "Cannot use relative backing file names for '%s'",
backed);
+ return NULL;
} else {
- path_combine_deprecated(dest, sz, backed, backing);
+ return path_combine(backed, backing);
}
}
@@ -309,9 +317,20 @@ void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz,
Error **errp)
{
char *backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename;
+ char *full_name;
+ Error *local_error = NULL;
- bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file,
- dest, sz, errp);
+ full_name = bdrv_get_full_backing_filename_from_filename(backed,
+ bs->backing_file,
+ &local_error);
+ if (full_name) {
+ pstrcpy(dest, sz, full_name);
+ g_free(full_name);
+ } else if (local_error) {
+ error_propagate(errp, local_error);
+ } else if (sz > 0) {
+ *dest = '\0';
+ }
}
void bdrv_register(BlockDriver *bdrv)
@@ -4593,17 +4612,17 @@ void bdrv_img_create(const char *filename, const char *fmt,
size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, img_size);
if (backing_file && !(flags & BDRV_O_NO_BACKING)) {
BlockDriverState *bs;
- char *full_backing = g_new0(char, PATH_MAX);
+ char *full_backing;
int back_flags;
QDict *backing_options = NULL;
- bdrv_get_full_backing_filename_from_filename(filename, backing_file,
- full_backing, PATH_MAX,
- &local_err);
+ full_backing =
+ bdrv_get_full_backing_filename_from_filename(filename, backing_file,
+ &local_err);
if (local_err) {
- g_free(full_backing);
goto out;
}
+ assert(full_backing);
/* backing files always opened read-only */
back_flags = flags;
@@ -2001,16 +2001,15 @@ static int vmdk_create(const char *filename, QemuOpts *opts, Error **errp)
}
if (backing_file) {
BlockBackend *blk;
- char *full_backing = g_new0(char, PATH_MAX);
- bdrv_get_full_backing_filename_from_filename(filename, backing_file,
- full_backing, PATH_MAX,
- &local_err);
+ char *full_backing =
+ bdrv_get_full_backing_filename_from_filename(filename, backing_file,
+ &local_err);
if (local_err) {
- g_free(full_backing);
error_propagate(errp, local_err);
ret = -ENOENT;
goto exit;
}
+ assert(full_backing);
blk = blk_new_open(full_backing, NULL, NULL,
BDRV_O_NO_BACKING, errp);