fix(dnn/cuda-stub): simplify and use proper search paths

Removed the `access()` call before `dlopen()`.
It was copy-pasted from the opencl-stub, does not make sense here, and
prevents `dlopen()` from loading `libcuda.so` from non-default path.

Updated the name of the library providing CUDA Driver API on different
platforms, these are harvested from the following file in a CUDA
install:
samples/6_Advanced/matrixMulDynlinkJIT/cuda_drvapi_dynlink.c
GitOrigin-RevId: ed43cab8c8b4a9b9f8baaa958e8b5123b72dd179

dnn/cuda-stub/src/libcuda.cpp

-/*
- *   LIBCUDA_PATH: candidate paths to libcuda.so; multiple paths are
- *   splitted by colons
- **/
-
 #pragma GCC visibility push(default)
 
 #include <cstdio>
@@ -15,25 +10,12 @@ extern "C" {
 
 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
 
-static const char* default_so_paths[] = {
-    "/usr/local/nvidia/lib64/libcuda.so",
-    "/usr/lib/x86_64-linux-gnu/libcuda.so",
-    "libcuda.so",
-};
-
 #if defined(_WIN32)
-#include <io.h>
 #include <windows.h>
-#define F_OK 0
 #define RTLD_LAZY 0
-// On the windows platform we use a lib_filename without a full path so
-// the win-api "LoadLibrary" would uses a standard search strategy to
-// find the lib module. As we cannot access to the lib_filename without a
-// full path, we should not use "access(a, b)" to verify it.
-#define access(a, b) false
 
 static void* dlopen(const char* file, int) {
-    return static_cast<void*>(LoadLibrary(file));
+    return static_cast<void*>(LoadLibraryA(file));
 }
 
 static void* dlerror() {
@@ -68,55 +50,43 @@ CUresult on_init_failed(int func_idx) {
 #undef _WRAPLIB_CALLBACK
 #undef _WRAPLIB_API_CALL
 
-static bool open_shared_lib(const char* path, void*& handle) {
-    if (!access(path, F_OK)) {
-        handle = dlopen(path, RTLD_LAZY);
-        if (handle)
-            return true;
-        LOGE("cuda lib found but can not be opened: %s err=%s", path,
-             dlerror());
-    }
-    return false;
-}
+// Harvested from cuda_drvapi_dynlink.c
+static const char* default_so_paths[] = {
+#if defined(WIN32) || defined(_WIN32) || defined(WIN64) || defined(_WIN64)
+    "nvcuda.dll",
+#elif defined(__unix__) || defined (__QNX__) || defined(__APPLE__) || defined(__MACOSX)
+#if defined(__APPLE__) || defined(__MACOSX)
+    "/usr/local/cuda/lib/libcuda.dylib",
+#elif defined(__ANDROID__)
+#if defined (__aarch64__)
+    "/system/vendor/lib64/libcuda.so",
+#elif defined(__arm__)
+    "/system/vendor/lib/libcuda.so",
+#endif
+#else
+    "libcuda.so.1",
+    
+    // In case some users does not have correct search path configured in
+    // /etc/ld.so.conf
+    "/usr/lib/x86_64-linux-gnu/libcuda.so",
+    "/usr/local/nvidia/lib64/libcuda.so",
+#endif
+#else
+#error "Unknown platform"
+#endif
+};
 
 static void* get_library_handle() {
-    const char* path = nullptr;
-    auto str_cptr = getenv("LIBCUDA_PATH");
-    std::string str;
     void* handle = nullptr;
-
-    if (str_cptr) {
-        str = str_cptr;
-        char* p = &str[0];
-        const char* begin = p;
-        while (*p) {
-            if (*p == ':') {
-                *p = 0;
-                if (open_shared_lib(begin, handle)) {
-                    path = begin;
-                    break;
-                }
-                begin = p + 1;
-            }
-            ++p;
-        }
-        if (open_shared_lib(begin, handle)) {
-            path = begin;
-        }
-    }
-
-    if (!path) {
-        for (size_t i = 0; i < (sizeof(default_so_paths) / sizeof(char*));
-             i++) {
-            if (open_shared_lib(default_so_paths[i], handle)) {
-                path = default_so_paths[i];
-                break;
-            }
+    for (size_t i = 0; i < (sizeof(default_so_paths) / sizeof(char*)); i++) {
+        handle = dlopen(default_so_paths[i], RTLD_LAZY);
+        if (handle) {
+            break;
         }
     }
 
-    if (!path) {
-        LOGE("can not find cuda");
+    if (!handle) {
+        LOGE("Failed to load CUDA Driver API library");
         return nullptr;
     }
     return handle;
@@ -137,4 +107,3 @@ static void* resolve_library_func(void* handle, const char* func) {
     }
     return ret;
 }
-