Linux/MacOSX port of DriverLoader

[a1batross]

Not tested this at all. But this must work on Linux and OSX too, since they are provide same POSIX dlfcn.h.

Also here is little changes in exceptions, because it's too important to know why library isn't loaded.

This must be compiled with -ldl. (${CMAKE_DL_LIBS} variable in CMake)

[a1batross]

4 #5

[rpavlik]

Wow, great, thanks for the contribution, it's really appreciated! I just have two little tweaks to suggest (the one in the build file, then the one to remove the unnecessary ifdefs around constructors), and then just a general question about libdl usage, since that's something I write libraries to keep me from dealing with too often... then I'll be more than happy to merge this!

FWIW, you can actually "test" and run this without Vive hardware, as long as you have SteamVR installed, it'll have the driver in the expected location, so running the ViveLoader app (built with the project, just not installed) should take it through its basic paces. It won't get too far without the hardware but you'll be able to see if the loading of the library and such works properly.

[a1batross]

Yes, I have installed SteamVR. Ok, I will try to run it and fix all issues tomorrow. Thanks for review!

[a1batross]

a1ba@KubuntuPortable:/home/a1ba/projects/OSVR-Vive/build  git:(linux_osx_driverloader_port*) $ ./ViveDisplayExtractor 
[DisplayExtractor] Driver loaded, but no Vive is connected. Exiting

Finally, got it running. Also I fixed some mistypes in code, forgotten includes.

NOTE: it requires setting LD_LIBRARY_PATH variable(SteamVR dependencies). It may be useful for they, who have Vive and want use OSVR.

export LD_LIBRARY_PATH=${HOME}/.steam/steam/steamapps/common/SteamVR/drivers/lighthouse/bin/linux64/:${HOME}/.steam/ubuntu12_32/steam-runtime/amd64/lib/x86_64-linux-gnu/

NOTE2: For some reason, Valve have an invalid GCC detection macro. Here is a confirmation: https://github.com/ValveSoftware/openvr/pull/58 Maybe you need to define it somewhere. Something like:

#if defined(__GNUC__)
#define GNUC
#endif

[a1batross]

Ah... I forgot a charger for my laptop in home. If there is some issues, I will fix in next Monday.

[a1batross]

Is anyone alive here?

[rpavlik]

Sorry, I thought we were waiting for you to test this again.

[rpavlik]

FWIW, SearchPathExtender.h is supposed to handle the extension of LD_LIBRARY_PATH - if it's not doing it, or not doing it right, could you look at it and see what I got wrong when I sort of wrote the non-Windows part without testing?

[a1batross]

Okay, I will look for it. On Apr 12, 2016 3:12 AM, "Ryan Pavlik" notifications@github.com wrote:

FWIW, SearchPathExtender.h is supposed to handle the extension of LD_LIBRARY_PATH - if it's not doing it, or not doing it right, could you look at it and see what I got wrong when I sort of wrote the non-Windows part without testing?

— You are receiving this because you authored the thread. Reply to this email directly or view it on GitHub https://github.com/OSVR/OSVR-Vive/pull/10#issuecomment-208632319

[a1batross]

Sorry, I was been busy for a week.

There is a problem with libdl. Library does getenv("LD_LIBRARY_PATH") before the program starts and only once. So setting LD_LIBRARY_PATH in runtime is useless.

I see some workarounds: 1) Use execve() on nix. One-line solution. Portable. But need to access filename of executable and original argv. (reading /proc data is non-portable, so it's better save argv from main()). 2) Recursively resolve dependencies of driver library and dlopen() each. It requires tons of code: parsing each ELF file, loading it by absolute path and so on. 3) Write a "run.sh" script for nix-es. 4) Have your own libdl.

[rpavlik]

That's fine, I've been busy too. Think I may as well merge this as-is, but would be good to figure out how to improve the libdl situation.

I wonder what SteamVR does, since they have the same problem: they have to add each driver's directory to the library search path. In libfunctionality, which is basically the only other place I've done substantial dlopening of libraries myself cross-platform (Unity/.NET doesn't really count), I'd contemplated/thought we might need/want a libltdl backend, but I wasn't familiar enough with it and didn't do enough research to see if it allowed the flexibility we wanted, but it does have a concept of user search dirs - don't know if it handles transitive dependencies: https://www.gnu.org/software/libtool/manual/html_node/Libltdl-interface.html#index-lt_005fdladdsearchdir

In any case, while option 2 in the general case is difficult, for the specific case of just loading the Vive driver, we could manually look up and hard-code its dependencies and preload them - that's essentially what we had to do with Unity loading OSVR...

[rpavlik]

Yeah, I'll just go ahead and merge this as-is, after skimming some related things, if that sounds good with you - let me know if you're ready for me to merge it!

If you wouldn't mind, could you submit a pull request updating this page with the LD_LIBRARY_PATH workaround info under a Linux section? https://github.com/OSVR/OSVR-Docs/blob/master/Configuring/HTC-Vive.md

[a1batross]

I wonder what SteamVR does

I think it does the same thing as Steam itself. Just setting LD_LIBRARY_PATH before starting program. It's most easy and secure way. AFAIK, Steam before starting adds Steam Runtime path which provides libraries with same versions on different Linux distributions. Now Steam Runtime enabled by default(I remember that on early Steam Linux versions it was disabled and I recompiled libraries by hand XD).

I may write an example shell script which will detect steam-runtime, add it to LD_LIBRARY_PATH and start the app. But I little busy now. I will update both linux_osx_driverloader_port branch and the OSVR-Docs on a holidays.

[rpavlik]

Merging this - thanks for your contribution!

[rpavlik]

Just looked at the commits again - you got a lot more in than Linux support, thanks for catching my bugs! thank you so much!