RFC: fix problems with errors during quitting (killed.exp)

[Daniel Jacobowitz]

On Fri, Sep 05, 2003 at 11:53:55AM -0400, J. Johnston wrote:
> The following patch fixes the problem that occurs when an error happens 
> while
> quitting.  Often an error() call gets triggered and the poor user is thrown
> back to the gdb command line where they try to quit again.  I made an 
> attempt
> to fix a similar problem by handling ptrace errors in quitting, however, 
> thread-db.c gets
> into multiple precarious situations because it has to rely on libthread_db
> for information.  When the thread has been killed/maimed, it gets errors 
> when
> they are not expected and quitting becomes impossible.
> 
> My new strategy is to intercept error() calls during quitting.  Basically,
> a simple get/set function is set up to denote when we the user has confirmed
> a quit.  If we get into top.c:throw_exception() and quit has been 
> confirmed, it
> exits the program.  This handles any number of messy kill scenarios and 
> causes
> no regressions in the current testsuite.  It fixes gdb.threads/killed.exp.  
> I made the
> functions external so other parts of gdb can register a confirmed quit if 
> necessary.  I could
> make these routines static if this feature is not needed.  I chose to exit 
> with the
> code being passed on the jump.  There may be a better constant choice.
> 
> If anyone can think of scenario that this code is not going to handle 
> correctly that might
> not be exercised by the testsuite, please let me know.
> 
> Tested on x86 and ia64.
> 
> Comments?

My immediate concern is, does killed.exp leave a stopped binary around?

Other than that I like it.

> 2003-09-04  Jeff Johnston  <jjohnstn@redhat.com>
> 
> 	* top.h (get_quit_confirmed, set_quit_confirmed): New prototypes.
> 	* top.c (get_quit_confirmed, set_quit_confirmed): New functions.
> 	(throw_exception): If quit confirmed, exit instead of jumping.


-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer