[libvirt] [PATCH 14/30] storagefile: Parse qcow2 external data file

[Daniel Henrique Barboza]

On 10/7/19 6:49 PM, Cole Robinson wrote:
> This is tracked as a qcow2 extension, like backing store format
>
> Signed-off-by: Cole Robinson <crobinso at redhat.com>
> ---

Reviewed-by: Daniel Henrique Barboza <danielhb413 at gmail.com>


>   src/util/virstoragefile.c | 22 ++++++++++++++++++++--
>   1 file changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c
> index 621cc56e87..7e32d7619e 100644
> --- a/src/util/virstoragefile.c
> +++ b/src/util/virstoragefile.c
> @@ -202,6 +202,7 @@ qedGetBackingStore(char **, int *, const char *, size_t);
>   
>   #define QCOW2_HDR_EXTENSION_END 0
>   #define QCOW2_HDR_EXTENSION_BACKING_FORMAT 0xE2792ACA
> +#define QCOW2_HDR_EXTENSION_DATA_FILE 0x44415441
>   
>   #define QCOW2v3_HDR_FEATURES_INCOMPATIBLE (QCOW2_HDR_TOTAL_SIZE)
>   #define QCOW2v3_HDR_FEATURES_COMPATIBLE (QCOW2v3_HDR_FEATURES_INCOMPATIBLE+8)
> @@ -429,7 +430,8 @@ cowGetBackingStore(char **res,
>   static int
>   qcow2GetExtensions(const char *buf,
>                      size_t buf_size,
> -                   int *backingFormat)
> +                   int *backingFormat,
> +                   char **externalDataStoreRaw)
>   {
>       size_t offset;
>       size_t extension_start;
> @@ -508,6 +510,9 @@ qcow2GetExtensions(const char *buf,
>   
>           case QCOW2_HDR_EXTENSION_BACKING_FORMAT: {
>               VIR_AUTOFREE(char *) tmp = NULL;
> +            if (!backingFormat)
> +                break;
> +
>               if (VIR_ALLOC_N(tmp, len + 1) < 0)
>                   return -1;
>               memcpy(tmp, buf + offset, len);
> @@ -516,6 +521,19 @@ qcow2GetExtensions(const char *buf,
>               *backingFormat = virStorageFileFormatTypeFromString(tmp);
>               if (*backingFormat <= VIR_STORAGE_FILE_NONE)
>                   return -1;
> +            break;
> +        }
> +
> +        case QCOW2_HDR_EXTENSION_DATA_FILE: {
> +            if (!externalDataStoreRaw)
> +                break;
> +
> +            if (VIR_ALLOC_N(*externalDataStoreRaw, len + 1) < 0)
> +                return -1;
> +            memcpy(*externalDataStoreRaw, buf + offset, len);
> +            (*externalDataStoreRaw)[len] = '\0';
> +            VIR_DEBUG("parsed externalDataStoreRaw='%s'", *externalDataStoreRaw);
> +            break;
>           }
>           }
>   
> @@ -566,7 +584,7 @@ qcowXGetBackingStore(char **res,
>       memcpy(*res, buf + offset, size);
>       (*res)[size] = '\0';
>   
> -    if (qcow2GetExtensions(buf, buf_size, format) < 0)
> +    if (qcow2GetExtensions(buf, buf_size, format, NULL) < 0)
>           return BACKING_STORE_INVALID;
>   
>       return BACKING_STORE_OK;