[PATCH] cygwin_rexec() returns pointer to deallocated memory

Peter Rosin peda@lysator.liu.se
Mon May 26 20:39:00 GMT 2014


On 2014-05-26 18:35, Christopher Faylor wrote:
> On Mon, May 26, 2014 at 04:27:10PM +0100, David Stacey wrote:
>> On 26/05/14 14:36, Peter Rosin wrote:
>>> I believe the comment refers to if "static" is the right answer to the
>>> problem. Is there a need to handle concurrent calls?
>>
>> I can't really comment on that. As the code stands, neither of the two 
>> functions that we are discussing are reentrant. As long as the author 
>> and the user(s) of the routines are both aware of that then it isn't a 
>> problem.
>>
>> I was just trying to fix a coding error that was picked up by Coverity 
>> Scan; it wasn't my intention to question the design.
> 
> But that is the usual problem with Coverity.  Making the simple, obvious
> fix to correct a Coverity warning isn't necessarily the right way to
> deal with the issue.
> 
> In this case, the linux man page says:
> 
>   ATTRIBUTES
>      Multithreading (see pthreads(7))
> 	 The rexec() and rexec_af() functions are not thread-safe.
> 
> so static is appropriate.

"Not thread-safe" doesn't automatically mean that a following call may mess
with what was returned from a prior call (by the same thread). But since
it (IMHO) is a poor interface with no description of how to free any
possibly allocated memory, I agree that static is the only viable option.

Cheers,
Peter



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