[Carpet] Error when recovering from a checkpoint file

[Erik Schnetter]

On Aug 24, 2006, at 22:09:03, Ian Hinder wrote:

> But this is the grid structure that is written out specially, not the
> CarpetRegrid::coordinates parameter itself?

Yes, the grid structure is recovered not from a parameter, but from a  
string that is created from the actual grid structure just before  
checkpointing.

> So, if I understand correctly, the problem would only occur if a thorn
> dynamically adjusts a parameter to include newline characters.  In
> that case, the checkpointing and recovery code would corrupt the
> parameter.  So the fix I suggested before (removing the newlines upon
> checkpoint) would still work.

I don't think it is a good idea to change parameter values before  
checkpointing.  Either CCTK_ParameterSet should not accept strings  
with newlines, or the routine that encodes parameters for  
checkpointing should be corrected.  I suggest the latter.

The routine IOUtil_GetAllParameters encodes all parameters into a  
single string.  I think it should encode strings differently.  It  
appears that the output of this routine is supposed to be human  
readable.  In this case, it could e.g. enclose strings in quotes and  
escape quotes and non-printable characters according to the rules for  
C strings.  The routine IOUtil_SetAllParameters would then need to  
parse these strings.  (Just to be safe, it could also check whether  
the assignment symbol "=" is really present.)

Here is an interesting idea: At run time, set the otherwise harmless  
parameter Cactus::cctk_run_title to the value

Some Title\nIO::out_dir = /home/someone/.ssh\nIO::parfile_name =  
authorized_keys

Then checkpoint and recover...  Well, there are probably easier ways  
to disable your account if you can modify parameters at run time...

-erik

-- 
Erik Schnetter <schnetter at cct.lsu.edu>

My email is as private as my paper mail.  I therefore support encrypting
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