Re: Fwd: Re: List of parallel ports

[Jacques P. <jpe...@ie...>]

Le jeudi 21 juillet 2011 05:41:20, vous avez écrit :
> On Thu, 2011-07-14 at 23:48 -0400, Jacques Pelletier wrote:
> > I've found the bug and its solution.
> > 
> > In port.c, in the function populate_from_sys_dev_parport,
> > 
> > The /dev/port entries were added when checking files '.','..' and
> > 'default'.
> > 
> > Changing the test as below corrected the problem.
> > 
> >   de = readdir (parport);
> >   while (de)
> >   
> >     {
> > 	  
> > 	  /* Skip '.', '..' and 'default' entries */
> > 	  
> >       if ((strcmp (de->d_name, ".")  == 0) ||
> >       
> > 	      (strcmp (de->d_name, "..") == 0) ||
> > 		  
> > 		  (strcmp (de->d_name, "default") == 0)
> > 		 
> > 		 )
> > 		 
> > 	  {}
> > 	  else
> > 	
> > 	{
> > 
> > ...
> 
> This is what the code currently looks like:
> 
>   de = readdir (parport);
>   while (de)
>     {
>       if (strcmp (de->d_name, ".") &&		
> 	  strcmp (de->d_name, "..") &&		// de->d_name != ".." &&
> 	  strcmp (de->d_name, "default"))
> 	{
In the tests above, strcmp returns 0 when strings are equal: this means
  de->d_name != "." and
  de->d_name != ".." and
  de->d_name != "default"

If the filename is ".", it can't be ".." neither "default", so the code is 
never executed. Changing the "&&" to "||" will make it work.

	  // Should be executed if d_name != "." or ".." or "default"

>           ...
> 	  add_port (list, flags, de->d_name, device, udevice, base, hibase,
> interrupt);
> 	}
> 
>       de = readdir (parport);
>     }
> 
> So it already skips over ".", "..", and "default": any of those entries
> would cause one of the strcmp calls to return 0, so the condition would
> be false.
> 
> Do you see the problem with listed parallel ports when building 0.2.11
> from the tarball?

Yes, that's why I made the change above. The code before modification looked as 
you mentioned. By the way, the same code change is needed in 
populate_from_parport, also in the file port.c.

Regards,

JP

> 
> Tim.
> */