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

[eddyb]

VK-GL-CTS/framework/delibs/deutil/deDynamicLibrary.c

Lines 40 to 49 in 50e8312

	deDynamicLibrary *deDynamicLibrary_open(const char *fileName)
	{
	deDynamicLibrary *library = (deDynamicLibrary *)deCalloc(sizeof(deDynamicLibrary));
	if (!library)
	return NULL;
	if (getenv("LD_LIBRARY_PATH"))
	library->libHandle = dlopen(basename((char *)fileName), RTLD_LAZY);
	else
	library->libHandle = dlopen(fileName, RTLD_LAZY);

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]

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 5aa5b08 (Vulkan Video tests).

[Flakebi]

I opened #495 to fix this