Re: [dpdk-dev] [PATCH 2/2] ethdev: use strlcpy instead of snprintf on initialization

[Stephen Hemminger <stephen@networkplumber.org>]

On Mon, 4 Mar 2019 12:11:20 +0300
Andrew Rybchenko <arybchenko@solarflare.com> wrote:

> On 3/1/19 9:42 PM, Stephen Hemminger wrote:
> > On Fri, 1 Mar 2019 10:48:58 +0300
> > Andrew Rybchenko <arybchenko@solarflare.com> wrote:
> >  
> >> On 3/1/19 1:47 AM, Stephen Hemminger wrote:  
> >>> Don't need to use snprintf for simple name copy.
> >>>
> >>> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> >>> ---
> >>>    lib/librte_ethdev/rte_ethdev.c | 2 +-
> >>>    1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
> >>> index 95889ed206db..8bd54dcf58c1 100644
> >>> --- a/lib/librte_ethdev/rte_ethdev.c
> >>> +++ b/lib/librte_ethdev/rte_ethdev.c
> >>> @@ -459,7 +459,7 @@ rte_eth_dev_allocate(const char *name)
> >>>    	}
> >>>    
> >>>    	eth_dev = eth_dev_get(port_id);
> >>> -	snprintf(eth_dev->data->name, sizeof(eth_dev->data->name), "%s", name);
> >>> +	strlcpy(eth_dev->data->name, name, RTE_ETH_NAME_MAX_LEN);  
> >> Why is sizeof() substituted with RTE_ETH_NAME_MAX_LEN?  
> > Same thing, I just wanted to make the length obvious to the reader.
> >  
> >> I thought that sizeof() is the first choice in such cases since it is a
> >> bit more
> >> safer vs possible changes in the code.
> >>
> >> BTW, wouldn't it be more friendly to check name length on entry and
> >> reject if it is too long? (and same for rte_eth_dev_create())  
> > It is impossible for name to long since since both structures are the same.  
> 
> Which structures? name is an input parameter of the function.
> 

Sorry my confusion, that was in patch 1.