CS:S - Player.drop_weapon crash

[Frag1337]

Hello,

when using following snippet while being on a team/alive on the server:

from filters.players import PlayerIter

for player in PlayerIter():
    print('Trying to remove weapons from {}..'.format(player.name))

    for weapon in player.weapons():
        print('Found {} from {}. Lets drop it.'.format(weapon.classname, player.name))

        player.drop_weapon(weapon)

        print('Aaand remove it..')

        weapon.remove()

I get following crash:

sp plugin load test
[SP] Loading plugin 'test'...
Trying to remove weapons from Frag..
Found weapon_knife from Frag. Lets drop it.
Segmentation fault (core dumped)
Add "-debug" to the ./srcds_run command line to generate a debug.log to help with solving this problem
Mon Dec 14 19:40:46 UTC 2020: Server restart in 10 seconds

sp info

IMPORTANT: Please copy the full output.
--------------------------------------------------------
Checksum      : 17af3a55546e8fed9c8e9b322e817b97
Date          : 2020-12-14 19:43:07.359723
OS            : Linux-5.4.0-58-generic-x86_64-with-debian-bullseye-sid
Game          : css
SP version    : 702
Github commit : 99ed4dca7b439f5fc4ade054355767b23af497df
Server plugins:
   00: Source.Python, (C) 2012-2020, Source.Python Team.
SP plugins:
--------------------------------------------------------

The server also crashes on

weapon.remove()

by uncommenting player.drop_weapon(weapon)

sp plugin load test
[SP] Loading plugin 'test'...
Trying to remove weapons from Frag..
Found weapon_knife from Frag. Lets drop it.
Aaand remove it..
Segmentation fault (core dumped)
Add "-debug" to the ./srcds_run command line to generate a debug.log to help with solving this problem
Mon Dec 14 19:45:04 UTC 2020: Server restart in 10 seconds

Not sure if its helpful, but I've used this fix to make Source.Python work:

https://forums.sourcepython.com/viewtopic.php?p=13976#p13976 Method 2

[CookStar]

What happens when you install libffi6 using this method?
Of course, don't forget to remove the symbolic link to libffi7.

[Frag1337]

What happens when you install libffi6 using this method?
Of course, don't forget to remove the symbolic link to libffi7.

I removed the symlink and used that method but it gave me an error with the package not being compitable.

So I downloaded the file manually, dropped it into /home/user/ and ran it with sudo apt install ./libffi6_3.2.1-9_i386.deb successfully. Sadly the same results from top.

Can someone replicate this? Is it a wrong offset or something different? I sadly have no idea about solving crashes :/

In another issue (#334 (comment)) I mentioned that I've reinstalled 2x VMs on my Windows 10 PC with Debian and Ubuntu and both crashed when using this snippet aswell. With Debian not requiring a workaround for libffi6, but sadly resulted in the same crash.

[CookStar]

What happens if you try this code?
Change player.drop_weapon(weapon) to drop_weapon_test(player, weapon).

def drop_weapon_test(player, weapon):
    import ctypes
    from memory.hooks import set_hooks_disabled
    functype = ctypes.CFUNCTYPE(None, *(ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p))
    drop_weapon = functype(player.drop_weapon.address)
    player_p = ctypes.c_void_p(player.pointer.address)
    weapon_p = ctypes.c_void_p(weapon.pointer.address)
    set_hooks_disabled(True)
    print("Drop the weapon by ctypes.")
    drop_weapon(player_p, weapon_p, None, None)
    print("Success.")
    set_hooks_disabled(False)

    player.equip_weapon(weapon)
    set_hooks_disabled(True)
    print("Drop the weapon.")
    player.drop_weapon(player, weapon)
    print("Success.")
    set_hooks_disabled(False)

[Frag1337]

What happens if you try this code?

sp plugin load test
[SP] Loading plugin 'test'...
1.1 Trying to remove weapons from Frag..
1.1 Found weapon_knife from Frag. Lets drop it.
2.1 Drop the weapon by ctypes.
2.2 Success.
Segmentation fault (core dumped)
Add "-debug" to the ./srcds_run command line to generate a debug.log to help with solving this problem
Thu Dec 17 22:04:45 UTC 2020: Server restart in 10 seconds

import ctypes
from memory.hooks import set_hooks_disabled
from filters.players import PlayerIter


def drop_weapon_test(player, weapon):
    functype = ctypes.CFUNCTYPE(None, *(ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p))
    drop_weapon = functype(player.drop_weapon.address)
    player_p = ctypes.c_void_p(player.pointer.address)
    weapon_p = ctypes.c_void_p(weapon.pointer.address)
    set_hooks_disabled(True)
    print("2.1 Drop the weapon by ctypes.")
    drop_weapon(player_p, weapon_p, None, None)
    print("2.2 Success.")
    set_hooks_disabled(False)

    player.equip_weapon(weapon)
    set_hooks_disabled(True)
    print("2.3 Drop the weapon.")
    player.drop_weapon(player, weapon)
    print("2.4 Success.")
    set_hooks_disabled(False)


for player in PlayerIter():
    print('1.1 Trying to remove weapons from {}..'.format(player.name))

    for weapon in player.weapons():
        print('1.1 Found {} from {}. Lets drop it.'.format(weapon.classname, player.name))

        drop_weapon_test(player, weapon)

Server crashed :/

[CookStar]

I should have disabled the hook in equip_weapon as well... my bad.

How about this code?

Code:

def drop_weapon_test(player, weapon):
    set_hooks_disabled(True)
    print("2.1 Drop the weapon.")
    player.drop_weapon(player, weapon)
    print("2.2 Success.")
    set_hooks_disabled(False)

[Frag1337]

How about this code?

sp plugin load test
[SP] Loading plugin 'test'...
1.1 Trying to remove weapons from Frag..
1.1 Found weapon_knife from Frag. Lets drop it.
2.1 Drop the weapon.
Segmentation fault (core dumped)
Add "-debug" to the ./srcds_run command line to generate a debug.log to help with solving this problem
Thu Dec 17 22:32:55 UTC 2020: Server restart in 10 seconds

test.py

import ctypes
from memory.hooks import set_hooks_disabled
from filters.players import PlayerIter


def drop_weapon_test(player, weapon):
    set_hooks_disabled(True)
    print("2.1 Drop the weapon.")
    player.drop_weapon(player, weapon)
    print("2.2 Success.")
    set_hooks_disabled(False)


for player in PlayerIter():
    print('1.1 Trying to remove weapons from {}..'.format(player.name))

    for weapon in player.weapons():
        print('1.1 Found {} from {}. Lets drop it.'.format(weapon.classname, player.name))

        drop_weapon_test(player, weapon)

Still crashes.

[CookStar]

Still crashes.

Thanks for the test.

Yes, this seems to be an error caused by libffi.
Other users are experiencing the same issue on Ubuntu 20.04.

The problem is that I don't know how to solve it.
You can use ctypes to work around it, but that's not a solution at all.

I'll do some testing on Ubuntu.

[Frag1337]

Thanks for trying to help me, very appreciated!

It's so frustrating to have a perfect working plugin on a local windows srcds, but the moment you want to run them publicly on a linux machine, some features which usually worked before doesnt anymore.. Should I reinstall and downgrade to Ubuntu 18, should I switch to Debian? I just dont know because sadly I'm not experienced enough to solve these crashes by myself. Kind of out of my hands.

[CookStar]

Yes, this seems to be an error caused by libffi.

My guess of libffi was wrong.
I've added a fix to the problem. #375

[Frag1337]

Thank you so much for investigating this issue! Very appreciated. I hope it gets pushed very soon!

It would be awesome from you if you could checkout my other issues related to linux.. 👍

Edit: Sorry I havent seen you mentioned my issues in your pull request. You just made my day.