Re: [PATCH 1/2] tools: use memcpy instead of strncpy in getBridge

[Bertrand Marquis <Bertrand.Marquis@xxxxxxx>]

> On 6 Oct 2020, at 05:34, Jürgen Groß <jgross@xxxxxxxx> wrote:
> 
> On 05.10.20 18:02, Bertrand Marquis wrote:
>> Use memcpy in getBridge to prevent gcc warnings about truncated
>> strings. We know that we might truncate it, so the gcc warning
>> here is wrong.
>> Revert previous change changing buffer sizes as bigger buffers
>> are not needed.
>> Signed-off-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
>> ---
>>  tools/libs/stat/xenstat_linux.c | 9 +++++++--
>>  1 file changed, 7 insertions(+), 2 deletions(-)
>> diff --git a/tools/libs/stat/xenstat_linux.c 
>> b/tools/libs/stat/xenstat_linux.c
>> index d2ee6fda64..1db35c604c 100644
>> --- a/tools/libs/stat/xenstat_linux.c
>> +++ b/tools/libs/stat/xenstat_linux.c
>> @@ -78,7 +78,12 @@ static void getBridge(char *excludeName, char *result, 
>> size_t resultLen)
>>                              sprintf(tmp, "/sys/class/net/%s/bridge", 
>> de->d_name);
>>                              if (access(tmp, F_OK) == 0) {
>> -                                    strncpy(result, de->d_name, resultLen);
>> +                                    /*
>> +                                     * Do not use strncpy to prevent 
>> compiler warning with
>> +                                     * gcc >= 10.0
>> +                                     * If de->d_name is longer then 
>> resultLen we truncate it
>> +                                     */
>> +                                    memcpy(result, de->d_name, resultLen - 
>> 1);
> 
> I think you want min(NAME_MAX, resultLen - 1) for the length.

true, I will fix that and send a v2.

Cheers
Bertrand