From 9f07429e8873124c588847b0d499cb32b9410bdd Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Wed, 26 Nov 2014 17:20:26 +0100 Subject: block: JSON filenames and relative backing files When using a relative backing file name, qemu needs to know the directory of the top image file. For JSON filenames, such a directory cannot be easily determined (e.g. how do you determine the directory of a qcow2 BDS directly on top of a quorum BDS?). Therefore, do not allow relative filenames for the backing file of BDSs only having a JSON filename. Furthermore, BDS::exact_filename should be used whenever possible. If BDS::filename is not equal to BDS::exact_filename, the former will always be a JSON object. Signed-off-by: Max Reitz Signed-off-by: Kevin Wolf --- block.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-) (limited to 'block.c') diff --git a/block.c b/block.c index 86f2faa266..cf0867c9d7 100644 --- a/block.c +++ b/block.c @@ -305,19 +305,28 @@ void path_combine(char *dest, int dest_size, void bdrv_get_full_backing_filename_from_filename(const char *backed, const char *backing, - char *dest, size_t sz) + char *dest, size_t sz, + Error **errp) { - if (backing[0] == '\0' || path_has_protocol(backing)) { + if (backing[0] == '\0' || path_has_protocol(backing) || + path_is_absolute(backing)) + { pstrcpy(dest, sz, backing); + } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) { + error_setg(errp, "Cannot use relative backing file names for '%s'", + backed); } else { path_combine(dest, sz, backed, backing); } } -void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz) +void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz, + Error **errp) { - bdrv_get_full_backing_filename_from_filename(bs->filename, bs->backing_file, - dest, sz); + char *backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename; + + bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file, + dest, sz, errp); } void bdrv_register(BlockDriver *bdrv) @@ -1225,7 +1234,14 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) QDECREF(options); goto free_exit; } else { - bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX); + bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX, + &local_err); + if (local_err) { + ret = -EINVAL; + error_propagate(errp, local_err); + QDECREF(options); + goto free_exit; + } } if (!bs->drv || !bs->drv->supports_backing) { -- cgit v1.2.1