Feat[lwjgl]: add vulkan to lwjgl dlopen hook, move hook to new file

app_pojavlauncher/src/main/jni/Android.mk

@@ -46,6 +46,7 @@ LOCAL_SRC_FILES := \
     utils.c \
     stdio_is.c \
     java_exec_hooks.c \
+    lwjgl_dlopen_hook.c \
     driver_helper/nsbypass.c
 
 ifeq ($(TARGET_ARCH_ABI),arm64-v8a)

app_pojavlauncher/src/main/jni/egl_bridge.c

@@ -258,14 +258,18 @@ EXTERNAL_API void* pojavCreateContext(void* contextSrc) {
     return br_init_context((basic_render_window_t*)contextSrc);
 }
 
-EXTERNAL_API JNIEXPORT jlong JNICALL
-Java_org_lwjgl_vulkan_VK_getVulkanDriverHandle(ABI_COMPAT JNIEnv *env, ABI_COMPAT jclass thiz) {
-    printf("EGLBridge: LWJGL-side Vulkan loader requested the Vulkan handle\n");
-    // The code below still uses the env var because
+void* maybe_load_vulkan() {
+    // We use the env var because
     // 1. it's easier to do that
     // 2. it won't break if something will try to load vulkan and osmesa simultaneously
     if(getenv("VULKAN_PTR") == NULL) load_vulkan();
-    return strtoul(getenv("VULKAN_PTR"), NULL, 0x10);
+    return (void*) strtoul(getenv("VULKAN_PTR"), NULL, 0x10);
+}
+
+EXTERNAL_API JNIEXPORT jlong JNICALL
+Java_org_lwjgl_vulkan_VK_getVulkanDriverHandle(ABI_COMPAT JNIEnv *env, ABI_COMPAT jclass thiz) {
+    printf("EGLBridge: LWJGL-side Vulkan loader requested the Vulkan handle\n");
+    return (jlong) maybe_load_vulkan();
 }
 
 EXTERNAL_API void pojavSwapInterval(int interval) {

app_pojavlauncher/src/main/jni/input_bridge_v3.c

@@ -228,47 +228,6 @@ void sendData(int type, int i1, int i2, int i3, int i4) {
     atomic_fetch_add_explicit(&pojav_environ->eventCounter, 1, memory_order_acquire);
 }
 
-/**
- * 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);
-    }
-}
-
 /**
  * This function is meant as a substitute for SharedLibraryUtil.getLibraryPath() that just returns 0
  * (thus making the parent Java function return null). This is done to avoid using the LWJGL's default function,

app_pojavlauncher/src/main/jni/lwjgl_dlopen_hook.c

@@ -0,0 +1,64 @@
+//
+// Created by maks on 06.01.2025.
+//
+
+#include <android/api-level.h>
+#include <android/log.h>
+#include <jni.h>
+
+#include <environ/environ.h>
+
+#include <dlfcn.h>
+#include <string.h>
+#include <stdlib.h>
+
+extern void* maybe_load_vulkan();
+
+/**
+ * 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
+ * but with our own additions for stuff like vulkanmod.
+ */
+static jlong ndlopen_bugfix(__attribute__((unused)) JNIEnv *env,
+                     __attribute__((unused)) jclass class,
+                     jlong filename_ptr,
+                     jint jmode) {
+    const char* filename = (const char*) filename_ptr;
+
+    // Oveeride vulkan loading to let us load vulkan ourselves
+    if(strstr(filename, "libvulkan.so") == filename) {
+        printf("LWJGL linkerhook: replacing load for libvulkan.so with custom driver\n");
+        return (jlong) maybe_load_vulkan();
+    }
+
+    // This hook also serves the task of mitigating a bug: 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
+
+    int mode = (int)jmode;
+    return (jlong) dlopen(filename, mode);
+}
+
+/**
+ * Install the LWJGL dlopen hook. This allows us to mitigate linker bugs and add custom library overrides.
+ */
+void installLinkerBugMitigation() {
+    __android_log_print(ANDROID_LOG_INFO, "LwjglLinkerHook", "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, "LwjglLinkerHook", "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, "LwjglLinkerHook", "Failed to register the hooked method");
+        (*env)->ExceptionClear(env);
+    }
+}