search

KhronosGroup / VK-GL-CTS

Khronos Vulkan, OpenGL, and OpenGL ES Conformance Tests
https://www.khronos.org/
Apache License 2.0
521 stars 290 forks source link

deDynamicLibrary_open intentionally(?) truncates its argument when LD_LIBRARY_PATH is set. #479

Open eddyb opened 1 month ago

eddyb commented 1 month ago

https://github.com/KhronosGroup/VK-GL-CTS/blob/50e83129b5587b60400ff90abb24bb658630c3eb/framework/delibs/deutil/deDynamicLibrary.c#L40-L49

I don't understand the purpose of such code in production - it looks like a testing hack that got accidentally committed?

The environment variable LD_LIBRARY_PATH, just like PATH, can contain arbitrary entries that should be ignored whenever they are irrelevant to the program itself.

Only way I could see this kind of logic making sense is trying both dlopen(basename((char *)fileName), RTLD_LAZY) and dlopen(fileName, RTLD_LAZY), when LD_LIBRARY_PATH is set (because, yes, they can pick different libraries).

But which one should you prefer? If the user explicitly passed e.g.: --deqp-vk-library-path=/my/local/build/of/vulkan-loader/lib/libvulkan.so Why would that full path be ignored in favor of just libvulkan.so?

Also, even with LD_LIBRARY_PATH unset, there is a hardcoded list of search directories built into libdl, so dlopen("libfoo.so") could still succeed even then. (think /lib64, but also e.g. automatically appending subpaths like glibc-hwcaps/x86-64-v3/ etc.)

Personally, I had deqp-vk work before, and it so happens that LD_LIBRARY_PATH isn't set for me normally (e.g. in Konsole), but something or other leads to it being set in VSCode, and I was running deqp-vk from inside VSCode this time.

eddyb commented 1 month ago

I don't understand the purpose of such code in production - it looks like a testing hack that got accidentally committed?

Maybe I was right about this, I didn't go back further in time once I saw that the last time I used deqp-vk the code would've been the same.

But apparently this started with https://github.com/KhronosGroup/VK-GL-CTS/commit/5aa5b0809f055f36fc384644925c384596b2f7cd (Vulkan Video tests).