Re: [cdt-dev] launching a gdb from inside a docker container using DSF/G

["Avery, Brian" <brian.avery@xxxxxxxxx>]

Hi, 


On 3/21/16, 8:41 AM, "cdt-dev-bounces@xxxxxxxxxxx on behalf of Roland
Grunberg" <cdt-dev-bounces@xxxxxxxxxxx on behalf of rgrunber@xxxxxxxxxx>
wrote:

>> Here's what I'm trying to do that is not succeeding:
>> I am trying to launch a gdb binary that resides in a docker container by
>> setting my gdb binary to :
>> docker-exec -i linux_gdb /usr/bin/gdb
>> 
>> This fails with:
>> cannot enable tty mode on non tty input
>> 
>> on both the gdb -version check and the actual --mi call.
>> 
>> The code that launches gdb does not seem to have a tty/pty  attached to
>>it.
>> There is code in the spawner class that seems to have this option but
>>that
>> is not being used by the gdb launcher.
>> 
>> Is there some way to accomplish this?
>
>I'm able to reproduce this error if I launch with '-i -t' using
>java.lang.Runtime's process launcher. Are you sure you were using just
>'-i' ?
>When I disabled my '-t' option I was getting output from gdb.
Hmm, I need to set up a simpler test case to compare to but I'm pretty
	certain I tried both the -i and the -it version. I can only try this on a
mac at the moment since I am travelling, but it looks like you are
correct. I was *certain* I tried both from the linux Eclipse but maybe I
am mistaken.


> 
>I haven't been playing around with this approach so can't really say
>what's
>going on but perhaps someone who knows Spawner better might have some
>hints.
>
>
>> -----
>> why I care is below in case people are wondering:
>> We have linux based docker containers that have cross toolchains for
>>various
>> targets installed in them. They also contain gdb for that architecture.
>> Our
>> longer term goal is to have metadata in the toolchain containers so that
>> they can "tell" the plugin what their capabilities are and so a limited
>> cross toolchain configuration UI can be constructed on the fly based on
>>the
>> toolchain container the user has chosen.
>> 
>> We would like to be able to use the cross toolchains in the container.
>>We are
>> accomplishing this currently using a native stub dispatcher and an
>>Eclipse
>> builder.  This works currently.
>> 
>> We would also like to be able to use the gdb inside the docker
>>container as
>> the gdb executable which Eclipse connects to.  The workspace is bind
>>mounted
>> into the container so the gdb inside the container can see the sources
>>and
>> binaries.  This works fine when we are executing from a shell
>>environment
>> (CLI mode). However, when we are executing it via eclipse (if we do
>> something like gdb = docker exec -I <debug_container> gdb-x86-64) we get
>> failures due to the lack of a tty available to the gdb inside the
>>container.
>
>Have you considered having a gdb-server within the container and simply
>connecting to it through a remote debug session ? This should bypass the
>issue you're having with the TTY, and is also similar to the approach the
>CDT's Container Debugging support took [1].

Good question. The main reason is that we are targeting a large number of
architectures and the overhead of maintaining and testing the toolchains
on the native os's is what we are trying to avoid.  The actual code is
typically running on an embedded board and we are talking to the gdbserver
on the board or to openocd on  the host talking jtag to the board.  The
targets don't tend to be containers or suitable to containerizing (if
that's a word).


This made me go back and try the basics again. That helped a lot.
Thanks!
Brian

>
>Cheers,
>-- 
>Roland Grunberg
>
>[1] https://wiki.eclipse.org/CDT/User/NewIn87#Docker_support
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