Fix two crashes that prevent a fresh install from launching

app/wfbngrtl8812/src/main/cpp/WfbngLink.cpp

@@ -48,8 +48,33 @@ std::string generate_random_string(size_t length) {
     return result;
 }
 
+// context.getFilesDir().getAbsolutePath() -- resolved at runtime instead of
+// hardcoding the package name, so both keyPath and the USB advisory lock
+// directory (see run() below) keep working under a different applicationId
+// or a non-default Android user profile.
+static std::string resolveFilesDir(JNIEnv *env, jobject context) {
+    jclass contextClass = env->GetObjectClass(context);
+    jmethodID getFilesDirMethod = env->GetMethodID(contextClass, "getFilesDir", "()Ljava/io/File;");
+    jobject filesDir = env->CallObjectMethod(context, getFilesDirMethod);
+
+    jclass fileClass = env->GetObjectClass(filesDir);
+    jmethodID getAbsolutePathMethod = env->GetMethodID(fileClass, "getAbsolutePath", "()Ljava/lang/String;");
+    auto pathString = (jstring)env->CallObjectMethod(filesDir, getAbsolutePathMethod);
+
+    const char *pathChars = env->GetStringUTFChars(pathString, nullptr);
+    std::string path = std::string(pathChars);
+    env->ReleaseStringUTFChars(pathString, pathChars);
+
+    env->DeleteLocalRef(filesDir);
+    env->DeleteLocalRef(fileClass);
+    env->DeleteLocalRef(contextClass);
+    return path;
+}
+
 WfbngLink::WfbngLink(JNIEnv *env, jobject context)
         : current_fd(-1), adaptive_link_enabled(true), adaptive_tx_power(30) {
+    filesDir = resolveFilesDir(env, context);
+    keyPath = filesDir + "/gs.key";
     initAgg();
     log = std::make_shared<Logger>(); // routes to logcat under the "devourer" tag
     wifi_driver = std::make_unique<WiFiDriver>(log);
@@ -117,8 +142,9 @@ int WfbngLink::run(JNIEnv *env, jobject context, jint wifiChannel, jint bw, jint
     // Jaguar1 (RTL8812AU) ignores it.
     cfg.rx.enable_with_tx = true;
     // The per-adapter advisory lock defaults to /tmp, which doesn't exist on
-    // Android — use the app's files dir (same location as gs.key).
-    cfg.usb.lock_dir = "/data/user/0/com.openipc.pixelpilot/files";
+    // Android — use the app's files dir (same location as gs.key, resolved in
+    // the constructor rather than hardcoded -- see resolveFilesDir() above).
+    cfg.usb.lock_dir = filesDir;
     // Keep the RX ring on plain heap buffers. The zerocopy dev-mem path
     // (libusb_dev_mem_alloc / USBDEVFS mmap) is unvalidated on Android vendor
     // kernels; if the mmap succeeds but the HCD's zerocopy path is broken,

app/wfbngrtl8812/src/main/cpp/WfbngLink.hpp

@@ -122,7 +122,14 @@ class WfbngLink {
         }
     }
 
-    const char *keyPath = "/data/user/0/com.openipc.pixelpilot/files/gs.key";
+    // Resolved from the running app's own Context.getFilesDir() in the
+    // constructor instead of hardcoding the package name, so this keeps
+    // working under a different applicationId (a fork/rebrand) or a
+    // non-default Android user profile (secondary user, work profile,
+    // Samsung Secure Folder, ...), where "/data/user/0/<pkg>" isn't the
+    // app's actual data directory.
+    std::string filesDir;
+    std::string keyPath;
     std::recursive_mutex thread_mutex;
     std::unique_ptr<WiFiDriver> wifi_driver;
     std::shared_ptr<TxFrame> txFrame;