From 9f07429e8873124c588847b0d499cb32b9410bdd Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Wed, 26 Nov 2014 17:20:26 +0100 Subject: [PATCH] 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 ++++++++++++++++++++++------ block/qapi.c | 7 ++++++- include/block/block.h | 5 +++-- 3 files changed, 31 insertions(+), 9 deletions(-) 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) { diff --git a/block/qapi.c b/block/qapi.c index fa68ba731f..a6fd6f7ab2 100644 --- a/block/qapi.c +++ b/block/qapi.c @@ -214,7 +214,12 @@ void bdrv_query_image_info(BlockDriverState *bs, info->backing_filename = g_strdup(backing_filename); info->has_backing_filename = true; bdrv_get_full_backing_filename(bs, backing_filename2, - sizeof(backing_filename2)); + sizeof(backing_filename2), &err); + if (err) { + error_propagate(errp, err); + qapi_free_ImageInfo(info); + return; + } if (strcmp(backing_filename, backing_filename2) != 0) { info->full_backing_filename = diff --git a/include/block/block.h b/include/block/block.h index eac9bb0957..9efaa80f91 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -396,10 +396,11 @@ const char *bdrv_get_encrypted_filename(BlockDriverState *bs); 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); + 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); + char *dest, size_t sz, + Error **errp); int bdrv_is_snapshot(BlockDriverState *bs); int path_has_protocol(const char *path);