block: update string sizes for filename,backing_file,exact_filename
The string field entries 'filename', 'backing_file', and
'exact_filename' in the BlockDriverState struct are defined as 1024
bytes.
However, many places that use these values accept a maximum of PATH_MAX
bytes, so we have a mixture of 1024 byte and PATH_MAX byte allocations.
This patch makes the BlockDriverStruct field string sizes match usage.
This patch also does a few fixes related to the size that needs to
happen now:
* the block qapi driver is updated to use PATH_MAX bytes
* the qcow and qcow2 drivers have an additional safety check
* the block vvfat driver is updated to use PATH_MAX bytes
for the size of backing_file, for systems where PATH_MAX is < 1024
bytes.
* qemu-img uses PATH_MAX rather than 1024. These instances were not
changed to be dynamically allocated, however, as the extra
temporary 3K in stack usage for qemu-img does not seem worrisome.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/qemu-img.c b/qemu-img.c
index 7876258..4e9a7f5 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2556,7 +2556,7 @@
/* For safe rebasing we need to compare old and new backing file */
if (!unsafe) {
- char backing_name[1024];
+ char backing_name[PATH_MAX];
blk_old_backing = blk_new_with_bs("old_backing", &error_abort);
bs_old_backing = blk_bs(blk_old_backing);
@@ -2614,7 +2614,7 @@
}
old_backing_num_sectors = bdrv_nb_sectors(bs_old_backing);
if (old_backing_num_sectors < 0) {
- char backing_name[1024];
+ char backing_name[PATH_MAX];
bdrv_get_backing_filename(bs, backing_name, sizeof(backing_name));
error_report("Could not get size of '%s': %s",