Error when trying to launch REPL

[julie-nga]

Hello,
I'm trying to launch REPL. To compile DRAKVUF with REPL, I used meson setup build --native-file llvm.ini -Drepl=true and ninja -C build.

When I try to launch it, with libdrakvuf.py being in the same directory as the REPL binary, I have :

ju@ju-virtual-machine:~/drakvuf/build$ sudo ./repl -r /root/win7-sp1.json -d win7-sp1 -l /etc/libvmi.conf
No libdrakvuf.py found, please generate it before running REPL
ju@ju-virtual-machine:~/drakvuf/build$ sudo ./repl -r /root/win7-sp1.json -d win7-sp1 -l /etc/libvmi.conf
xc: error: Failed to enable vm_event
 (16 = Device or resource busy): Internal error
VMI_ERROR: vm_event is (or was) active on this domain
Failed to init LibVMI library.
Failed to initialize on domain win7-sp1
ju@ju-virtual-machine:~/drakvuf/build$ 

The first time I run that command causes the introspected VM to freeze and not be running anymore.

Does anyone know how to launch REPL correctly ?

NB: The arguments of the repl command:

ju@ju-virtual-machine:~/drakvuf/build$ ./repl
Required input:
	 -r <path to json>         The OS kernel's JSON
	 -d <domain ID or name>    The domain's ID or name
	 -l                        Use libvmi.conf
	 -k <kpgd value>           Use provided KPGD value for faster and more robust startup (advanced)

[ohault]

Hi @tklengyel, can you please help us about this issue to get REPL working with the current version of Drakvuf ?

[tklengyel]

I haven't personally used REPL since its been contributed but it was working at the time it was merged. I recommend taking a look at the PR it was originally contributed to see if it has bitrotted since then somehow.

[BonusPlay]

My guess is that during the migration to meson generation of libdrakvuf.py was skipped. PR #824 provides command that was used to generate that file, you can always just generate it "by hand".
There are also some examples on the wiki: https://github.com/tklengyel/drakvuf/wiki/REPL-introduction-guide

[tklengyel]

Yea, at the time I couldn't figure out how to launch ctypesgen from meson and it got forgotten. It's a bug/TODO.