GDB exits and debugging stops with -d <pid> on a running process (PyInf#10417)

[dshivashankar1994]

I noticed that here we exit the GDB launched using inject and the debugging happens outside of the GDB.

The code in here checks for the presence of the gdb process and exits the debugging if not.

The gdb process stops and becomes a zombie process. Earlier the issue was not exposed as the zombie process was not considered as non-existing - which was fixed in commit 6ee02b8.

[dshivashankar1994]

Expanding the issue a little bit

Because Zombie process are treated as existing (tried to solve in 6ee02b8), say we do 'py -d ' and while this is active we issue second 'py -d ' on the same pid, command hangs forever

Basically, GDB doesn't support connecting multiple GDB to same process and hence it exits when an active GDB is already connected with the process.

Couple of things to be modified to fix this issue are with inject method (here)

1. PIPE the stdout and stderr to be used later instead of "_dev_null" (if show_output is False)
2. Return process instead of process.id so that the process.stdout and process.stderr can be processed by the watchdog process

Since this is a public facing API, we should see how we can take care of the above changes as the signature gets modified with above change.