Re: [Qemu-devel] [PATCH 1/6] bochs: Fix bdrv_open() error handling

[Markus Armbruster]

Kevin Wolf <address@hidden> writes:

> Return -errno instead of -1 on errors. While touching the
> code, fix a memory leak.
>
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
>  block/bochs.c |   22 +++++++++++++++-------
>  1 files changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/block/bochs.c b/block/bochs.c
> index 3737583..a6eb33d 100644
> --- a/block/bochs.c
> +++ b/block/bochs.c
> @@ -114,11 +114,13 @@ static int bochs_open(BlockDriverState *bs, int flags)
>      int i;
>      struct bochs_header bochs;
>      struct bochs_header_v1 header_v1;
> +    int ret;
>  
>      bs->read_only = 1; // no write support yet
>  
> -    if (bdrv_pread(bs->file, 0, &bochs, sizeof(bochs)) != sizeof(bochs)) {
> -        goto fail;
> +    ret = bdrv_pread(bs->file, 0, &bochs, sizeof(bochs));
> +    if (ret < 0) {
> +        return ret;
>      }
>  
>      if (strcmp(bochs.magic, HEADER_MAGIC) ||
           strcmp(bochs.type, REDOLOG_TYPE) ||
           strcmp(bochs.subtype, GROWING_TYPE) ||
           ((le32_to_cpu(bochs.version) != HEADER_VERSION) &&
           (le32_to_cpu(bochs.version) != HEADER_V1))) {

I'm afraid you need to set ret here.  I wonder why the compiler didn't
flag it.

           goto fail;
       }
> @@ -138,9 +140,13 @@ static int bochs_open(BlockDriverState *bs, int flags)
>  
>      s->catalog_size = le32_to_cpu(bochs.extra.redolog.catalog);
>      s->catalog_bitmap = g_malloc(s->catalog_size * 4);
> -    if (bdrv_pread(bs->file, le32_to_cpu(bochs.header), s->catalog_bitmap,
> -                   s->catalog_size * 4) != s->catalog_size * 4)
> -     goto fail;
> +
> +    ret = bdrv_pread(bs->file, le32_to_cpu(bochs.header), s->catalog_bitmap,
> +                     s->catalog_size * 4);
> +    if (ret < 0) {
> +        goto fail;
> +    }
> +
>      for (i = 0; i < s->catalog_size; i++)
>       le32_to_cpus(&s->catalog_bitmap[i]);
>  
> @@ -153,8 +159,10 @@ static int bochs_open(BlockDriverState *bs, int flags)
>  
>      qemu_co_mutex_init(&s->lock);
>      return 0;
> - fail:
> -    return -1;
> +
> +fail:
> +    g_free(s->catalog_bitmap);
> +    return ret;
>  }
>  
>  static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)