2014-09-18 10:51 GMT+02:00 Dan Carpenter <dan.carpenter@xxxxxxxxxx>:
> On Thu, Sep 18, 2014 at 12:12:42AM +0200, Rickard Strandqvist wrote:
>> Hi Dan
>>
>> Ok, I have made two suggestions for strncpy function that also
>> guarantees a terminating null character.
>> 1) retunerar number of characters to be copied, it can be good to
>> have, but was not really satisfied.
>
> strlcpy() is more popular the strncpy() in the kernel.
>
> No one uses the return value of strncpy() because what is the point?
> There are around 15-20 places which use the return value of strlcpy().
> Some of the place which use the return value assume that the copy fits.
>
> I think we should return the number of bytes before the NUL or else
> count.
>
>>
>> int strncpyz(char *dest, const char *src, size_t count)
>> {
>> size_t len=0;
>>
>> if(0 == count)
>> return 0;
>>
>> --count;
>> while(len < count && src[len])
>> *dest++ = src[len++];
>>
>> do {
>> *dest++ = '\0';
>> }
>> while(len < count--);
>>
>> return len;
>> }
>>
>>
>> 2) The next version is almost the same code as the regular strncpy,
>> but with two extra lines.
>>
>> char *strncpyz(char *dest, const char *src, size_t count)
>> {
>> char *tmp = dest;
>>
>> while (count) {
>> if ((*tmp = *src) != 0)
>> src++;
>> tmp++;
>> count--;
>> }
>>
>> if(tmp != dest)
>> *--tmp = '\0';
>>
>> return dest;
>> }
>>
>>
>> Since I did not got any better solution to variant 1, I prefer variant 2.
>
> I also prefer variant 2.
>
>>
>> Then the next question is of course what it should be called :-)
>
> I think a lot of people call this function strzcpy().
>
> This sort of patch would go through Andrew Morton.
>
> regards,
> dan carpenter
Hi Dan
Ok, strzcpy is it :)
Should I add this as a patch in lib/string.c or email him first.. What
is customary in these situations?
Kind regards
Rickard Strandqvist
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