Fix[lwjgl]: add Android API <30 linker issue mitigation

app_pojavlauncher/src/main/jni/input_bridge_v3.c

@@ -60,6 +60,7 @@ jint JNI_OnLoad(JavaVM* vm, __attribute__((unused)) void* reserved) {
         jobject mouseDownBufferJ = (*pojav_environ->runtimeJNIEnvPtr_JRE)->GetStaticObjectField(pojav_environ->runtimeJNIEnvPtr_JRE, pojav_environ->vmGlfwClass, field_mouseDownBuffer);
         pojav_environ->mouseDownBuffer = (*pojav_environ->runtimeJNIEnvPtr_JRE)->GetDirectBufferAddress(pojav_environ->runtimeJNIEnvPtr_JRE, mouseDownBufferJ);
         hookExec();
+        installLinkerBugMitigation();
     }
 
     if(pojav_environ->dalvikJavaVMPtr == vm) {
@@ -252,6 +253,46 @@ void hookExec() {
     printf("Registered forkAndExec\n");
 }
 
+/**
+ * Basically a verbatim implementation of ndlopen(), found at
+ * https://github.com/PojavLauncherTeam/lwjgl3/blob/3.3.1/modules/lwjgl/core/src/generated/c/linux/org_lwjgl_system_linux_DynamicLinkLoader.c#L11
+ * The idea is that since, on Android 10 and earlier, the linker doesn't really do namespace nesting.
+ * It is not a problem as most of the libraries are in the launcher path, but when you try to run
+ * VulkanMod which loads shaderc outside of the default jni libs directory through this method,
+ * it can't load it because the path is not in the allowed paths for the anonymous namesapce.
+ * This method fixes the issue by being in libpojavexec, and thus being in the classloader namespace
+ */
+jlong ndlopen_bugfix(__attribute__((unused)) JNIEnv *env,
+                     __attribute__((unused)) jclass class,
+                     jlong filename_ptr,
+                     jint jmode) {
+    const char* filename = (const char*) filename_ptr;
+    int mode = (int)jmode;
+    return (jlong) dlopen(filename, mode);
+}
+
+/**
+ * Install the linker bug mitigation for Android 10 and lower. Fixes VulkanMod crashing on these
+ * Android versions due to missing namespace nesting.
+ */
+void installLinkerBugMitigation() {
+    if(android_get_device_api_level() >= 30) return;
+    __android_log_print(ANDROID_LOG_INFO, "Api29LinkerFix", "API < 30 detected, installing linker bug mitigation");
+    JNIEnv* env = pojav_environ->runtimeJNIEnvPtr_JRE;
+    jclass dynamicLinkLoader = (*env)->FindClass(env, "org/lwjgl/system/linux/DynamicLinkLoader");
+    if(dynamicLinkLoader == NULL) {
+        __android_log_print(ANDROID_LOG_ERROR, "Api29LinkerFix", "Failed to find the target class");
+        (*env)->ExceptionClear(env);
+        return;
+    }
+    JNINativeMethod ndlopenMethod[] = {
+            {"ndlopen", "(JI)J", &ndlopen_bugfix}
+    };
+    if((*env)->RegisterNatives(env, dynamicLinkLoader, ndlopenMethod, 1) != 0) {
+        __android_log_print(ANDROID_LOG_ERROR, "Api29LinkerFix", "Failed to register the bugfix method");
+        (*env)->ExceptionClear(env);
+    }
+}
 
 void critical_set_stackqueue(jboolean use_input_stack_queue) {
     pojav_environ->isUseStackQueueCall = (int) use_input_stack_queue;

app_pojavlauncher/src/main/jni/utils.h

@@ -10,5 +10,6 @@ void free_char_array(JNIEnv *env, jobjectArray jstringArray, const char **charAr
 jstring convertStringJVM(JNIEnv* srcEnv, JNIEnv* dstEnv, jstring srcStr);
 
 void hookExec();
+void installLinkerBugMitigation();
 JNIEXPORT jstring JNICALL Java_org_lwjgl_glfw_CallbackBridge_nativeClipboard(JNIEnv* env, jclass clazz, jint action, jbyteArray copySrc);