Re: [PATCH v3] tools/libs/stat: fix broken build

[Bertrand Marquis <Bertrand.Marquis@xxxxxxx>]

Hi Juergen,

> On 14 Sep 2020, at 11:58, Bertrand Marquis <bertrand.marquis@xxxxxxx> wrote:
> 
> 
> 
>> On 12 Sep 2020, at 14:08, Juergen Gross <jgross@xxxxxxxx> wrote:
>> 
>> Making getBridge() static triggered a build error with some gcc versions:
>> 
>> error: 'strncpy' output may be truncated copying 15 bytes from a string of
>> length 255 [-Werror=stringop-truncation]
>> 
>> Fix that by using a buffer with 256 bytes instead.
>> 
>> Fixes: 6d0ec053907794 ("tools: split libxenstat into new tools/libs/stat 
>> directory")
>> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>

Sorry i have to come back on this one.

I still see an error compiling with Yocto on this one:
|     inlined from 'xenstat_collect_networks' at xenstat_linux.c:306:2:
| xenstat_linux.c:81:6: error: 'strncpy' output may be truncated copying 255 
bytes from a string of length 255 [-Werror=stringop-truncation]
|    81 |      strncpy(result, de->d_name, resultLen);
|       |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To solve it, I need to define devBridge[257] as devNoBrideg.

Regards
Bertrand

> 
>> ---
>> tools/libs/stat/xenstat_linux.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>> 
>> diff --git a/tools/libs/stat/xenstat_linux.c 
>> b/tools/libs/stat/xenstat_linux.c
>> index 793263f2b6..d2ee6fda64 100644
>> --- a/tools/libs/stat/xenstat_linux.c
>> +++ b/tools/libs/stat/xenstat_linux.c
>> @@ -78,7 +78,7 @@ 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 - 
>> 1);
>> +                                    strncpy(result, de->d_name, resultLen);
>>                                      result[resultLen - 1] = 0;
>>                              }
>>              }
>> @@ -264,7 +264,7 @@ int xenstat_collect_networks(xenstat_node * node)
>> {
>>      /* Helper variables for parseNetDevLine() function defined above */
>>      int i;
>> -    char line[512] = { 0 }, iface[16] = { 0 }, devBridge[16] = { 0 }, 
>> devNoBridge[17] = { 0 };
>> +    char line[512] = { 0 }, iface[16] = { 0 }, devBridge[256] = { 0 }, 
>> devNoBridge[257] = { 0 };
>>      unsigned long long rxBytes, rxPackets, rxErrs, rxDrops, txBytes, 
>> txPackets, txErrs, txDrops;
>> 
>>      struct priv_data *priv = get_priv_data(node->handle);
>> -- 
>> 2.26.2
>> 
>> 
>