On Tue, 2 Dec 2014 15:39:14 +0800
Fam Zheng <f...@redhat.com> wrote:
> Zeroing a buffer that will be filled right after is not necessary, and
> allocating a power of two + 1 is naughty.
>
> Suggested-by: Markus Armbruster <arm...@redhat.com>
> Signed-off-by: Fam Zheng <f...@redhat.com>
> ---
> block/vmdk.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/block/vmdk.c b/block/vmdk.c
> index 28d22db..0c5769c 100644
> --- a/block/vmdk.c
> +++ b/block/vmdk.c
> @@ -558,14 +558,15 @@ static char *vmdk_read_desc(BlockDriverState *file,
> uint64_t desc_offset,
> }
>
> size = MIN(size, 1 << 20); /* avoid unbounded allocation */
> - buf = g_malloc0(size + 1);
> + buf = g_malloc(size);
For a file that is less than 1<<20 bytes, won't this throw away the last byte?
Maybe better is:
size = MIN(size, (1 << 20) - 1);
buf = g_malloc(size + 1);
Leave the bdrv_pread as it was and...
>
> - ret = bdrv_pread(file, desc_offset, buf, size);
> + ret = bdrv_pread(file, desc_offset, buf, size - 1);
> if (ret < 0) {
> error_setg_errno(errp, -ret, "Could not read from file");
> g_free(buf);
> return NULL;
> }
> + buf[ret - 1] = 0;
...zero the last byte changes to:
buf[ret] = 0;
>
> return buf;
> }
> --
> 1.9.3
-d
