[SLOF] GCC compiler warning in create_crc.c

[Alexey Kardashevskiy]

On 18/7/18 7:59 pm, Thomas Huth wrote:
> On 18.07.2018 11:26, Alexey Kardashevskiy wrote:
>>
>>
>> On 17/7/18 9:33 pm, Thomas Huth wrote:
>>>
>>>  Hi all,
>>>
>>> when compiling SLOF with GCC 8.1, I currently get these compiler warnings:
>>>
>>> create_crc.c: In function ‘createHeaderImage’:
>>> create_crc.c:110:2: warning: ‘strncpy’ output truncated before
>>> terminating nul copying 8 bytes from a string of the same length
>>> [-Wstringop-truncation]
>>>   strncpy(uHeader.stHeader.magic, FLASHFS_MAGIC, 8);
>>>   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> create_crc.c:86:3: warning: ‘strncpy’ specified bound 16 equals
>>> destination size [-Wstringop-truncation]
>>>    strncpy(uHeader.stHeader.version, pcVersion, 16);
>>>    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> create_crc.c:84:3: warning: ‘strncpy’ specified bound 16 equals
>>> destination size [-Wstringop-truncation]
>>>    strncpy(uHeader.stHeader.version, pcVersion, 16);
>>>    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>
>>> As far as I can see, the code is prefectly fine, since the fields in the
>>> header do not have to be NUL-terminated here. Still, it's annoying to
>>> see a compiler warning here every time you re-compile SLOF.
>>>
>>> Does anybody have a good suggestion how to silence these? Simply use
>>> "-Wno-stringop-truncation" for compiling that file? ... but then we
>>> first have to check whether the compiler supports that flag, and that's
>>> also kind of ugly. Or should we rework the code? ... that's certainly
>>> possible, but in this case, it sounds so unnecessary...
>>>
>>> I really don't have a suggestion for a really nice clean solution
>>> here... anybody else got a good idea?
>>
>> Strangely my gcc 8.1.1 built from the sources does not throw these
>> errors on power7 box (and it did complain about the other bugs you
>> posted weeks ago), I wonder what is the difference to your gcc :-/
> 
> No clue, I am also using 8.1.1 ... did you do a "make distclean"
> inbetween to make sure that the romfs tool is really rebuilt?

Yes. Just updated gcc from git, 3 weeks old gcc-8-branch, compiled with
"--with-newlib --disable-shared --disable-threads" and I do not see the
warnings. What is your setup?


-- 
Alexey