Re: [PATCH 3/4] tools/libxl: Fix libxl__device_nic_from_xs_be()

["Roger Pau Monné" <roger.pau@citrix.com>]

On 25/11/13 12:12, Andrew Cooper wrote:
> Coverity ID: 1055886
> 
> The callers of xs_read() is required to free the allocated memory.  Also avoid
> calling libxl__parse_mac(NULL,) if the second xs_read() fails.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> CC: Ian Campbell <Ian.Campbell@citrix.com>
> CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
> ---
>  tools/libxl/libxl.c |   11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
> index 2b847ef..d8dae3e 100644
> --- a/tools/libxl/libxl.c
> +++ b/tools/libxl/libxl.c
> @@ -2983,14 +2983,15 @@ static void libxl__device_nic_from_xs_be(libxl__gc *gc,
>      libxl_ctx *ctx = libxl__gc_owner(gc);
>      unsigned int len;
>      char *tmp;
> -    int rc;
>  
>      libxl_device_nic_init(nic);
>  
>      tmp = xs_read(ctx->xsh, XBT_NULL,
>                    libxl__sprintf(gc, "%s/handle", be_path), &len);

It might be easier to just use libxl__xs_read_checked since you are
changing that code.

> -    if ( tmp )
> +    if ( tmp ) {
>          nic->devid = atoi(tmp);
> +        free(tmp);
> +    }
>      else
>          nic->devid = 0;
>  
> @@ -2998,10 +2999,12 @@ static void libxl__device_nic_from_xs_be(libxl__gc *gc,
>  
>      tmp = xs_read(ctx->xsh, XBT_NULL,
>                    libxl__sprintf(gc, "%s/mac", be_path), &len);
> -    rc = libxl__parse_mac(tmp, nic->mac);
> -    if (rc)
> +
> +    if ( !tmp || libxl__parse_mac(tmp, nic->mac) != 0 )
>          memset(nic->mac, 0, sizeof(nic->mac));
>  
> +    free(tmp);
> +
>      nic->ip = xs_read(ctx->xsh, XBT_NULL,
>                        libxl__sprintf(gc, "%s/ip", be_path), &len);
>  
>