[dm-devel] [PATCH 20/21] libmultipath: dm_get_uuid(): return emtpy UUID for non-existing maps

[Benjamin Marzinski]

On Fri, Sep 01, 2023 at 08:02:33PM +0200, mwilck at suse.com wrote:
> From: Martin Wilck <mwilck at suse.com>
> 
> libdevmapper will most probably not return a UUID for non-existing
> maps anyway. But it's cheap to double-check here.
> 
Reviewed-by: Benjamin Marzinski <bmarzins at redhat.com>
> Signed-off-by: Martin Wilck <mwilck at suse.com>
> ---
>  libmultipath/devmapper.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
> index 248c373..9be82f4 100644
> --- a/libmultipath/devmapper.c
> +++ b/libmultipath/devmapper.c
> @@ -706,12 +706,16 @@ dm_get_prefixed_uuid(const char *name, char *uuid, int uuid_len)
>  {
>  	struct dm_task *dmt;
>  	const char *uuidtmp;
> +	struct dm_info info;
>  	int r = 1;
>  
>  	dmt = libmp_dm_task_create(DM_DEVICE_INFO);
>  	if (!dmt)
>  		return 1;
>  
> +	if (uuid_len > 0)
> +		uuid[0] = '\0';
> +
>  	if (!dm_task_set_name (dmt, name))
>  		goto uuidout;
>  
> @@ -720,11 +724,13 @@ dm_get_prefixed_uuid(const char *name, char *uuid, int uuid_len)
>  		goto uuidout;
>  	}
>  
> +	if (!dm_task_get_info(dmt, &info) ||
> +	    !info.exists)
> +		goto uuidout;
> +
>  	uuidtmp = dm_task_get_uuid(dmt);
>  	if (uuidtmp)
>  		strlcpy(uuid, uuidtmp, uuid_len);
> -	else
> -		uuid[0] = '\0';
>  
>  	r = 0;
>  uuidout:
> -- 
> 2.41.0