Re: [Qemu-devel] [PATCH RESEND v2 1/2] qemu-file: Fix qemu_put_compression_data flaw

[Li, Liang Z]

Ping ...

Liang


> -----Original Message-----
> From: Li, Liang Z
> Sent: Friday, January 15, 2016 6:06 PM
> To: address@hidden
> Cc: address@hidden; address@hidden; address@hidden;
> address@hidden; Li, Liang Z
> Subject: [PATCH RESEND v2 1/2] qemu-file: Fix
> qemu_put_compression_data flaw
> 
> Current qemu_put_compression_data can only work with no writable
> QEMUFile, and can't work with the writable QEMUFile. But it does not
> provide any measure to prevent users from using it with a writable QEMUFile.
> 
> We should fix this flaw to make it works with writable QEMUFile.
> 
> Signed-off-by: Liang Li <address@hidden>
> ---
>  migration/qemu-file.c | 23 +++++++++++++++++++++--
>  1 file changed, 21 insertions(+), 2 deletions(-)
> 
> diff --git a/migration/qemu-file.c b/migration/qemu-file.c index
> 0bbd257..b956ab6 100644
> --- a/migration/qemu-file.c
> +++ b/migration/qemu-file.c
> @@ -606,8 +606,14 @@ uint64_t qemu_get_be64(QEMUFile *f)
>      return v;
>  }
> 
> -/* compress size bytes of data start at p with specific compression
> +/* Compress size bytes of data start at p with specific compression
>   * level and store the compressed data to the buffer of f.
> + *
> + * When f is not writable, return 0 if f has no space to save the
> + * compressed data.
> + * When f is wirtable and it has no space to save the compressed data,
> + * do fflush first, if f still has no space to save the compressed
> + * data, return 0.
>   */
> 
>  ssize_t qemu_put_compression_data(QEMUFile *f, const uint8_t *p, size_t
> size, @@ -616,7 +622,14 @@ ssize_t
> qemu_put_compression_data(QEMUFile *f, const uint8_t *p, size_t size,
>      ssize_t blen = IO_BUF_SIZE - f->buf_index - sizeof(int32_t);
> 
>      if (blen < compressBound(size)) {
> -        return 0;
> +        if (!qemu_file_is_writable(f)) {
> +            return 0;
> +        }
> +        qemu_fflush(f);
> +        blen = IO_BUF_SIZE - sizeof(int32_t);
> +        if (blen < compressBound(size)) {
> +            return 0;
> +        }
>      }
>      if (compress2(f->buf + f->buf_index + sizeof(int32_t), (uLongf *)&blen,
>                    (Bytef *)p, size, level) != Z_OK) { @@ -624,7 +637,13 @@ 
> ssize_t
> qemu_put_compression_data(QEMUFile *f, const uint8_t *p, size_t size,
>          return 0;
>      }
>      qemu_put_be32(f, blen);
> +    if (f->ops->writev_buffer) {
> +        add_to_iovec(f, f->buf + f->buf_index, blen);
> +    }
>      f->buf_index += blen;
> +    if (f->buf_index == IO_BUF_SIZE) {
> +        qemu_fflush(f);
> +    }
>      return blen + sizeof(int32_t);
>  }
> 
> --
> 1.9.1