Launch gdb to hook onto multiple existing processes (using a python script!)

Question

I'm writing a python script to go through my list of currently executing processes, look for the ones run by a certain user, and then run GDB to hook onto all of those.

I currently get a list of all the processes run by a certain user. (I used http://andreinc.net/2010/11/07/how-to-get-the-active-process-list-on-a-linux-machine-using-python/ for that)

However, I for the life of me can't square that with how to launch gdb and hook onto each of those with a separate inferior from Python. I know how to launch gdb with a Python script, just not with the appropriate sequencing to attach multiple processes inside that gdb and create an inferior for each one.

I know that once you're running gdb, you can create new inferiors with create-inferior, then switch to them and attach a process. Is there a way to add an inferior and immediately have it attach to a process?

Better yet, is there a way to launch gdb with multiple inferiors, each one attaching to a different process in the argument list?

Thanks!

Employed Russian · Accepted Answer · 2015-08-20 22:28:55Z

1

you can create new inferiors with create-inferior

You probably mean add-inferior. This works, but isn't very elegant:

$ sleep 1800 & sleep 1800 & sleep 1900 &
[1] 80375
[2] 80376
[3] 80377

$ gdb -q -ex 'attach 80375' \
  -ex 'add-inferior' -ex 'inferior 2' -ex 'attach 80376' \
  -ex 'add-inferior' -ex 'inferior 3' -ex 'attach 80377'
...
(gdb) info inferiors
  Num  Description       Executable
* 3    process 80377     /bin/sleep
  2    process 80376     /bin/sleep
  1    process 80375     /bin/sleep
(gdb) q
Detaching from program: /bin/sleep, process 80377
Detaching from program: /bin/sleep, process 80376
Detaching from program: /bin/sleep, process 80375

Consider filing a feature request in GDB bugzilla: if add-inferior accepted a pid (in addition to or instead of executable filename), your task would be simpler.

edited Aug 20, 2015 at 22:28

answered Aug 20, 2015 at 22:23

Employed Russian

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1 Comment

Ben Friedman Over a year ago

Thanks, yeah I did mean add-inferior...and thanks for the help! That feature request is a good idea, I may well ask for that!

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