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qemu-img: initialize MapEntry object

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Commit 16b0d555 introduced an issue where we are not initializing
has_filename for the 'next' MapEntry object, which leads to interesting
errors in both Valgrind and Clang -fsanitize=undefined.

Zero the stack object at allocation AND make sure the utility to
populate the fields properly marks has_filename as false if applicable.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
John Snow 2016-02-05 13:12:33 -05:00 committed by Kevin Wolf
parent c3bce9d5f9
commit 2875645b65
1 changed files with 15 additions and 11 deletions
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26
qemu-img.c
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@ -2194,6 +2194,7 @@ static int get_block_status(BlockDriverState *bs, int64_t sector_num,
int64_t ret;
int depth;
BlockDriverState *file;
bool has_offset;
/* As an optimization, we could cache the current range of unallocated
* clusters in each file of the chain, and avoid querying the same
@ -2220,17 +2221,20 @@ static int get_block_status(BlockDriverState *bs, int64_t sector_num,
depth++;
}
e->start = sector_num * BDRV_SECTOR_SIZE;
e->length = nb_sectors * BDRV_SECTOR_SIZE;
e->data = !!(ret & BDRV_BLOCK_DATA);
e->zero = !!(ret & BDRV_BLOCK_ZERO);
e->offset = ret & BDRV_BLOCK_OFFSET_MASK;
e->has_offset = !!(ret & BDRV_BLOCK_OFFSET_VALID);
e->depth = depth;
if (file && e->has_offset) {
e->has_filename = true;
e->filename = file->filename;
}
has_offset = !!(ret & BDRV_BLOCK_OFFSET_VALID);
*e = (MapEntry) {
.start = sector_num * BDRV_SECTOR_SIZE,
.length = nb_sectors * BDRV_SECTOR_SIZE,
.data = !!(ret & BDRV_BLOCK_DATA),
.zero = !!(ret & BDRV_BLOCK_ZERO),
.offset = ret & BDRV_BLOCK_OFFSET_MASK,
.has_offset = has_offset,
.depth = depth,
.has_filename = file && has_offset,
.filename = file && has_offset ? file->filename : NULL,
};
return 0;
}