Adding shared memory implementation

[Bernhard Reutner-Fischer]

On Tue, Jan 27, 2009 at 10:47:35AM +0100, Mikael Lund Jepsen, ICCC wrote:
> Bernhard Reutner-Fischer wrote:
>> This can simply be dropped into the proper tests/ subdir, no?
>>   
> I'm not yet familiar with the test suite, so I had not considered  
> putting it in there, but I think it is definitely a good idea.
> I just looked briefly at the (quite elaborate) test skeleton and a few  
> of the existing tests, but I did not see any unique pattern or  
> requirements to follow,
> so unless there are any special requirements to fit into the test  
> environment, I guess it could just be dropped in...

Please include the testsuite code in the diff, TIA.

> I tried looking around a bit for similar functions constructing paths.  
> Using FILENAME_MAX as in tempnam is just as bad, size wise.
> As I see it we can either impose a special (shorter) name lenght for  
> uclibc or dynamically allocate a buffer with an appropriate size.
> Any preferences?

just allocate a buffer (if that's allowed by the std, quote the standard above
the declaration otherwise).
>>> +
>>> +  /* Construct the filename.  */
>>> +  while (name[0] == '/')
>>> +    ++name;
>>> +
>>> +  /* create special shared memory file name and leave enough space to
>>> +     cause a path/name error if name is too long */
>>> +  strlcpy (shm_name + 9, name, PATH_MAX + 10);
>>>     
>> sounds like a BSD extension.
>>   
> Possibly - I'm not a BSD guy ;-)

So please try not to use it.