From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35011) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eGsP3-00088F-Pi for qemu-devel@nongnu.org; Mon, 20 Nov 2017 15:10:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eGsP2-0006xw-Nx for qemu-devel@nongnu.org; Mon, 20 Nov 2017 15:10:49 -0500 From: Max Reitz Date: Mon, 20 Nov 2017 21:09:46 +0100 Message-Id: <20171120201004.14999-8-mreitz@redhat.com> In-Reply-To: <20171120201004.14999-1-mreitz@redhat.com> References: <20171120201004.14999-1-mreitz@redhat.com> Subject: [Qemu-devel] [PATCH v7 for-2.12 07/25] block: bdrv_get_full_backing_filename_from_...'s ret. val. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Max Reitz , Kevin Wolf , Alberto Garcia , Eric Blake , John Snow Make bdrv_get_full_backing_filename_from_filename() return an allocated string instead of placing the result in a caller-provided buffer. Signed-off-by: Max Reitz Reviewed-by: Alberto Garcia --- include/block/block.h | 7 +++---- block.c | 51 +++++++++++++++++++++++++++++++++++---------------- block/vmdk.c | 9 ++++----- 3 files changed, 42 insertions(+), 25 deletions(-) diff --git a/include/block/block.h b/include/block/block.h index 4584893c78..46c6190414 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -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); diff --git a/block.c b/block.c index 8786b9b520..f8b3edd5bb 100644 --- a/block.c +++ b/block.c @@ -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; diff --git a/block/vmdk.c b/block/vmdk.c index 5397a4345e..c1dbcfe133 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -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); -- 2.13.6