Commit 2875645b authored by John Snow's avatar John Snow Committed by Kevin Wolf
Browse files

qemu-img: initialize MapEntry object 



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: default avatarJohn Snow <jsnow@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent c3bce9d5

qemu-img.c

+15 −11
Original line number Diff line number Diff line
@@ -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;

}