Godot: GDNative doesn't load shared libraries specified in .gdnlib depencendies

[and3rson]

Godot version:
3.0.6.stable.official.8314054

OS/device including version:
ArchLinux x64 rolling

Issue description:
Godot doesn't seem to properly load .gdnlib dependency during runtime.

Steps to reproduce:
I have a GDNative library libgaben.so that depends on libsteam_api.so. They're both in the root dir of the project. I'm able to resolve them via ldd which means they're linked properly:

$ LD_LIBRARY_PATH=. ldd libgaben.so 
        linux-vdso.so.1 (0x00007fff24798000)
        libsteam_api.so => ./libsteam_api.so (0x00007f045bef3000)
        libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00007f045bb6a000)
        libm.so.6 => /usr/lib/libm.so.6 (0x00007f045b7d5000)
        libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x00007f045b5bd000)
        libc.so.6 => /usr/lib/libc.so.6 (0x00007f045b201000)
        libdl.so.2 => /usr/lib/libdl.so.2 (0x00007f045affd000)
        libpthread.so.0 => /usr/lib/libpthread.so.0 (0x00007f045addf000)
        /usr/lib64/ld-linux-x86-64.so.2 (0x00007f045c36d000)

Now, I create a libgaben.gdnlib file:

[entry]

X11.64="res://libgaben.so"

[dependencies]

X11.64=[ "res://libsteam_api.so" ]

[general]

singleton=false
load_once=false
symbol_prefix="godot_"
reloadable=false

Then I create a NativeScript resource and try to instantiate it in my project and get this error:

0:00:00:0444 - Can't open dynamic library: /home/foobar/src/PROJECT_ROOT/libgaben.so. Error: libsteam_api.so: cannot open shared object file: No such file or directory
----------
Тип:Помилка
Опис: Can't open dynamic library: /home/foobar/src/PROJECT_ROOT/libgaben.so. Error: libsteam_api.so: cannot open shared object file: No such file or directory
Час: 0:00:00:0444
C Помилка: Method/Function Failed, returning: ERR_CANT_OPEN
C Джерело: drivers/unix/os_unix.cpp:379
C Функція: open_dynamic_library

Looks like Godot doesn't alter LD_LIBRARY_PATH for depencency libraries when loading entry library.

This is confirmed by the fact that the app works if I put my dependency (libsteam_api.so) into /usr/lib dir.

Any ideas?

[karroffel]

If you are on linux, try using RPATh instead of LD_LIBRARY_PATH.

LD_LIBRARY_PATH does a link-time lookup but also a fixed-location load-time lookup of the path.
RPATH does a link-time lookup and a dynamic location load-time lookup of the path.

So with RPATH you can load libraries relative to the working directory. This is more a unix-issue than a GDNative issue :P

[and3rson]

Using RPATH totally did the trick. Thanks!

For anyone having the same issue: I've added the following line to load my dependencies from lib dir which is located in the same folder as my library:

env.Append(LINKFLAGS=[
    '-Wl,-rpath,\'$$ORIGIN\'/lib'
])

It's a placeholder for the location of my library during runtime. It allows me to load my shared library and all its depencencies from any predefined relative location. Relevant SO answer: https://stackoverflow.com/a/38058216/3455614

Works on 64-bit Linux.

[aaronfranke]

@and3rson To elaborate on how to solve this I was having the same issue. I have my .so libraries in addons/git_for_godot/gdnative/linuxbsd in my project. I added this to the SConstruct:

env.Append(LINKFLAGS=[
    '-Wl,-rpath,addons/git_for_godot/gdnative/linuxbsd'
])

I ran echo $ORIGIN and it was blank, what is this variable supposed to be set to? I decided to just set the path to be relative, starting with addons/, and this allows ldd to detect the library, and Godot loads it without throwing any errors, but Godot crashes immediately after running, so I'm still missing something.