Re: [PATCH 2/4] libxenstat: YAJL_GET_STRING may return NULL

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 08/04/15 16:01, Wei Liu wrote:
> Passing NULL to strcmp can cause segmentation fault. Continue in that
> case.
>
> Signed-off-by: Wei Liu <wei.liu2@citrix.com>
> Cc: Ian Campbell <ian.campbell@citrix.com>
> Cc: Ian Jackson <ian.jackson@eu.citrix.com>
> Cc: Charles Arnold <carnold@suse.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

> ---
>  tools/xenstat/libxenstat/src/xenstat_qmp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/xenstat/libxenstat/src/xenstat_qmp.c b/tools/xenstat/libxenstat/src/xenstat_qmp.c
> index f3aeec4..6bfbc2f 100644
> --- a/tools/xenstat/libxenstat/src/xenstat_qmp.c
> +++ b/tools/xenstat/libxenstat/src/xenstat_qmp.c
> @@ -110,7 +110,7 @@ static char *qmp_get_block_image(xenstat_node *node, char *qmp_devname, int qfd)
>  		ptr[0] = qblock[QMP_BLOCK_DEVICE]; /* "device" */
>  		if ((dev_obj = yajl_tree_get(n, ptr, yajl_t_any)) != NULL) {
>  			tmp = YAJL_GET_STRING(dev_obj);
> -			if (strcmp(qmp_devname, tmp))
> +			if (!tmp || strcmp(qmp_devname, tmp))
>  				continue;
>  		}
>  		else