Re: [PATCH] Make only user-specified executable filenames sticky

Don Breazeal
2015-06-05T14:54:43Z

On 6/5/2015 2:37 AM, Gary Benson wrote:
> Don Breazeal wrote:
>> On 5/6/2015 3:26 AM, Gary Benson wrote:
>>> In GDB some executable files are supplied by the user (e.g. using
>>> a "file" command) and some are determined by GDB (e.g. while
>>> processing an "attach" command). GDB will not attempt to
>>> determine a filename if one has been set. This causes problems if
>>> you attach to one process and then attach to another: GDB will not
>>> attempt to discover the main executable on the second attach. If
>>> the two processes have different main executable files then the
>>> symbols will now be wrong.
>>>
>>> This commit updates GDB to keep track of which executable
>>> filenames were supplied by the user. When GDB might attempt to
>>> determine an executable filename and one is already set, filenames
>>> determined by GDB may be overridden but user-supplied filenames
>>> will not.
>>
>> I realize that I am coming late to this discussion, sorry about
>> that.
>
> Likewise, sorry for taking so long to reply :)
>
>> How does this interact with follow-exec-mode? If follow-exec-mode
>> is 'new' and the program execs, then 'run' will use the original
>> executable file. But if follow-exec-mode is 'same' and the program
>> execs, then 'run' will use the executable file that was active after
>> the exec call.
>>
>> In the follow-exec-mode == 'same' instance, is the assumption that
>> the exec'd executable file takes on the same 'user-supplied'
>> attribute as the initial executable, since it is using the original
>> inferior?
>>
>> If so, is there a scenario where:
>> * the user supplies the exec file name
>> * the program execs, so the exec file name is now different
>> * then the user tries to do an attach (without an exec file name) to a
>> process running the original exec file, and gets the wrong exec file name?
>
> I'm not sure. Where would I need to look to check this out?
> (Where is the bit that updates the filename after exec?)
>
Hi Gary
I think it goes like this: infrun.c:follow_exec calls
exec.c:exec_file_attach, which updates the name of the executable.

Sorry I haven't taken the time to review your patch to see how
it affects this. Hopefully it will be obvious to you.
Thanks
--Don