feat: experimental native hooks

native/.gitignore

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+/build

native/build.gradle.kts

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+@Suppress("DSL_SCOPE_VIOLATION") // TODO: Remove once KTIJ-19369 is fixed
+plugins {
+    alias(libs.plugins.androidLibrary)
+    alias(libs.plugins.kotlinAndroid)
+}
+
+android {
+    namespace = "me.rhunk.snapenhance.nativelib"
+    compileSdk = 34
+
+    defaultConfig {
+        externalNativeBuild {
+            cmake {
+                cppFlags("")
+            }
+        }
+    }
+
+    externalNativeBuild {
+        cmake {
+            path("jni/CMakeLists.txt")
+            version = "3.22.1"
+        }
+    }
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+}

native/jni/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.22.1)
+
+project("nativelib")
+
+set(DOBBY_GENERATE_SHARED OFF)
+add_subdirectory(external/dobby)
+
+add_library(${CMAKE_PROJECT_NAME} SHARED
+        src/library.cpp
+    )
+
+target_link_libraries(${CMAKE_PROJECT_NAME}
+        android
+        log
+        dobby_static
+        )

native/jni/src/config.h

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+#pragma once
+
+typedef struct {
+    bool disable_bitmoji;
+    bool disable_metrics;
+} native_config_t;

native/jni/src/library.cpp

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+#include <jni.h>
+#include <string>
+#include <dobby.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fstream>
+#include <vector>
+
+#include "logger.h"
+#include "config.h"
+
+static native_config_t *native_config;
+
+static auto fstat_original = fstat;
+static int fstat_hook(int fd, struct stat *buf) {
+    char name[256];
+    memset(name, 0, 256);
+    snprintf(name, sizeof(name), "/proc/self/fd/%d", fd);
+    readlink(name, name, sizeof(name));
+
+    auto fileName = std::string(name);
+
+    //prevent blizzardv2 metrics
+    if (native_config->disable_metrics && fileName.find("files/blizzardv2/queues") != std::string::npos) {
+        unlink(name);
+        return -1;
+    }
+
+    //prevent bitmoji to load
+    if (native_config->disable_bitmoji && fileName.find("com.snap.file_manager_4_SCContent") != std::string::npos) {
+        return -1;
+    }
+
+    return fstat_original(fd, buf);
+}
+
+
+#define GET_BOOL_FIELD(env, clazz, field) env->GetBooleanField(clazz, env->GetFieldID(clazz, field, "Z"))
+
+extern "C" JNIEXPORT void JNICALL
+loadConfig(JNIEnv *env, jobject  clazz, jobject config_object) {
+    auto native_config_class = env->GetObjectClass(config_object);
+
+    native_config->disable_bitmoji = GET_BOOL_FIELD(env, native_config_class, "disableBitmoji");
+    native_config->disable_metrics = GET_BOOL_FIELD(env, native_config_class, "disableMetrics");
+
+    LOGD("config loaded");
+}
+
+//jni onload
+extern "C" JNIEXPORT jint JNICALL
+JNI_OnLoad(JavaVM *vm, void *reserved) {
+    LOGD("initializing native");
+    // config
+    native_config = new native_config_t;
+
+    // hooks
+    DobbyHook((void *) fstat_original,(void *) fstat_hook,(void **) &fstat_original);
+
+    // register native methods
+    JNIEnv *env = nullptr;
+    vm->GetEnv((void **) &env, JNI_VERSION_1_6);
+
+    auto methods = std::vector<JNINativeMethod>();
+    methods.push_back({"loadConfig", "(Lme/rhunk/snapenhance/nativelib/NativeConfig;)V", (void *) loadConfig});
+
+    env->RegisterNatives(
+            env->FindClass("me/rhunk/snapenhance/nativelib/NativeLib"),
+            methods.data(),
+            methods.size()
+    );
+
+    LOGD("native initialized");
+
+    return JNI_VERSION_1_6;
+}

native/jni/src/logger.h

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+#pragma once
+
+#include <android/log.h>
+
+#define LOG_TAG "SnapEnhanceNative"
+
+#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, __VA_ARGS__)
+#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,  LOG_TAG, __VA_ARGS__)
+#define LOGW(...) __android_log_print(ANDROID_LOG_WARN,  LOG_TAG, __VA_ARGS__)
+

native/src/main/kotlin/me/rhunk/snapenhance/nativelib/NativeConfig.kt

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+package me.rhunk.snapenhance.nativelib
+
+data class NativeConfig(
+    val disableBitmoji: Boolean = false,
+    val disableMetrics: Boolean = false
+)

native/src/main/kotlin/me/rhunk/snapenhance/nativelib/NativeLib.kt

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+package me.rhunk.snapenhance.nativelib
+
+class NativeLib {
+    fun init() {
+        System.loadLibrary("nativelib")
+    }
+
+
+    external fun loadConfig(config: NativeConfig)
+}