Re: [PATCHv9 2.6.35-rc4-tip 10/13] perf: Re-Add make_absolute_path

[Srikar Dronamraju <srikar@linux.vnet.ibm.com>]

> 
> > Actually we dont need to convert malloc@libc-2.5.so to a
> > malloc@/lib/libc.so.6. Because we can match the shortname of the dso. 
> 
> Humm, I see, it is path based, so the first libc-2.5.so that appears in
> the LD_LIBRARY_PATH equivalent used in this code will be user, is that
> right?

No,  As you might have got it by reading patch 11. I am trying to
reuse the thread/session elements and walk thro the maps in the
map_groups. So I dont need to bother on LD_LIBRARY_PATH.
> 
> I.e. if I'm testing some new libc-2.5.so that provides, say, private
> futexes while the one in my distro still doesn't have this feature, I'll
> have to specify the absolute name or make sure it is before the system's
> libc-2.5.so in the LD_LIBRARY_PATH, right?

We get to the right one, as we walk the list of dsos in the
threadlist. But we have an option of either giving a correct full path
or the shortname for the dso without any path. However right now the
shortname has to be unique i.e I cant use malloc@libc instead of
malloc@libc-2.5.so. I would think specifying full path will be the most
probable usage case. However if a person refers /proc/<pid>/maps,
specifying shortnames should also be easy.

> 
> > Problem will occur when users specifies a full path of the file.
> > Since the file can refer to a symbolic link and the dso will have just
> > the short name or the target file name. Here I am using
> > make_absolute_path to resolve to the target file.
> > Now we can then either check on dso full names or short names.
> > I have chosen to use the short name.
> 
> Humm, so what you want is one of:
> 
> realpath - return the canonicalized absolute pathname
> canonicalize_file_name -  return the canonicalized filename
> 
> Can you please check the man pages for both before we decide
> re-introducing make_absolute_path?

right, realpath is right choice, I will use it instead of this patch. 


--
Thanks and Regards
Srikar