Refactor config access and URL hook redirects

Replace global host/port variables with a `HookConfig` struct and mutex-protected getters/setters to make configuration access thread-safe and consistently validated. In request/websocket hooks, centralize host patching with `maybeRedirect()` and a `QSet` whitelist, skipping redirects when config is invalid. Also consolidate symbol-hook setup into a shared helper with clearer error logging and library constants.

src/Config.cpp

@@ -9,18 +9,43 @@
 #include <cstring>
 #include <string>
 
+#include <QtCore/QMutex>
+#include <QtCore/QMutexLocker>
+
 #define TAG "RMHook"
 #define LOGI(...) __android_log_print(ANDROID_LOG_INFO, TAG, __VA_ARGS__)
 #define LOGW(...) __android_log_print(ANDROID_LOG_WARN, TAG, __VA_ARGS__)
 
-QString gConfiguredHost;
+extern "C" void startHooks();
-int gConfiguredPort = 0;
+
+static QMutex gConfigMutex;
+static HookConfig gConfig;
+
+HookConfig getConfiguration() {
+    QMutexLocker locker(&gConfigMutex);
+    return gConfig;
+}
+
+static bool setConfiguration(const QString &host, int port) {
+    HookConfig candidate{host.trimmed(), port};
+    if (!candidate.isValid()) {
+        return false;
+    }
+
+    QMutexLocker locker(&gConfigMutex);
+    gConfig = candidate;
+    return true;
+}
+
+static bool hasValidConfiguration() {
+    QMutexLocker locker(&gConfigMutex);
+    return gConfig.isValid();
+}
+
 
 static JavaVM *gJvm = nullptr;
 static jobject gContext = nullptr;
 
-extern "C" void startHooks();
-
 static JNIEnv *getJNIEnv() {
     if (!gJvm) {
         return nullptr;
@@ -47,20 +72,6 @@ static bool clearJavaException(JNIEnv *env, const char *operation) {
     return true;
 }
 
-static bool isValidConfig(const QString &host, int port) {
-    return !host.trimmed().isEmpty() && port > 0 && port <= 65535;
-}
-
-static bool setConfiguration(const QString &host, int port) {
-    if (!isValidConfig(host, port)) {
-        return false;
-    }
-
-    gConfiguredHost = host.trimmed();
-    gConfiguredPort = port;
-    return true;
-}
-
 static std::string trimLine(const char *value) {
     std::string line(value ? value : "");
     while (!line.empty() && (line.back() == '\n' || line.back() == '\r' || line.back() == ' ' || line.back() == '\t')) {
@@ -101,8 +112,9 @@ static bool loadFromConfigFile(const char *path) {
         return false;
     }
 
+    const HookConfig cfg = getConfiguration();
     LOGI("Loaded config from %s - Host: %s, Port: %d", path,
-         gConfiguredHost.toStdString().c_str(), gConfiguredPort);
+         cfg.host.toStdString().c_str(), cfg.port);
     return true;
 }
 
@@ -163,8 +175,9 @@ static bool loadFromSharedPrefs() {
         return false;
     }
 
+    const HookConfig cfg = getConfiguration();
     LOGI("Loaded config from SharedPreferences - Host: %s, Port: %d",
-         gConfiguredHost.toStdString().c_str(), gConfiguredPort);
+         cfg.host.toStdString().c_str(), cfg.port);
     return true;
 }
 
@@ -257,7 +270,7 @@ static void saveToSharedPrefs(const char *host, int port) {
 extern "C" {
 
 void loadConfiguration(void) {
-    if (gConfiguredPort > 0) {
+    if (hasValidConfiguration()) {
         return;
     }
 
@@ -270,10 +283,10 @@ void loadConfiguration(void) {
         return;
     }
 
-    gConfiguredHost = "example.com";
+    setConfiguration("example.com", 443);
-    gConfiguredPort = 443;
+    const HookConfig cfg = getConfiguration();
     LOGI("No saved config found. Using defaults - Host: %s, Port: %d",
-         gConfiguredHost.toStdString().c_str(), gConfiguredPort);
+         cfg.host.toStdString().c_str(), cfg.port);
 }
 
 void saveConfiguration(const char *host, int port) {
@@ -282,9 +295,10 @@ void saveConfiguration(const char *host, int port) {
         return;
     }
 
-    QByteArray hostBytes = gConfiguredHost.toUtf8();
+    const HookConfig cfg = getConfiguration();
-    saveToSharedPrefs(hostBytes.constData(), gConfiguredPort);
+    QByteArray hostBytes = cfg.host.toUtf8();
-    LOGI("Saved config - Host: %s, Port: %d", gConfiguredHost.toStdString().c_str(), gConfiguredPort);
+    saveToSharedPrefs(hostBytes.constData(), cfg.port);
+    LOGI("Saved config - Host: %s, Port: %d", cfg.host.toStdString().c_str(), cfg.port);
 }
 
 JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void *) {
@@ -312,7 +326,8 @@ JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void *) {
     }
 
     loadConfiguration();
-    LOGI("JNI_OnLoad: config loaded (%s:%d)", gConfiguredHost.toStdString().c_str(), gConfiguredPort);
+    const HookConfig cfg = getConfiguration();
+    LOGI("JNI_OnLoad: config loaded (%s:%d)", cfg.host.toStdString().c_str(), cfg.port);
     startHooks();
     return JNI_VERSION_1_6;
 }

src/Config.h

@@ -3,14 +3,23 @@
 
 #include <QtCore/QString>
 
-extern QString gConfiguredHost;
+struct HookConfig {
-extern int gConfiguredPort;
+    QString host;
+    int port = 0;
+
+    bool isValid() const {
+        return !host.trimmed().isEmpty() && port > 0 && port <= 65535;
+    }
+};
+
+HookConfig getConfiguration();
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 void loadConfiguration(void);
+
 void saveConfiguration(const char *host, int port);
 
 #ifdef __cplusplus

src/rmhook.cpp

@@ -8,6 +8,7 @@
 #include <stdint.h>
 
 #include <QtCore/QObject>
+#include <QtCore/QSet>
 #include <QtCore/QString>
 #include <QtCore/QUrl>
 #include <QtCore/QIODevice>
@@ -27,27 +28,54 @@
 #define LOGW(...) __android_log_print(ANDROID_LOG_WARN, TAG, __VA_ARGS__)
 #define LOGE(...) __android_log_print(ANDROID_LOG_ERROR, TAG, __VA_ARGS__)
 
+static const char *const kLibQtNetwork = "libQt6Network_arm64-v8a.so";
+static const char *const kLibQtWebSockets = "libQt6WebSockets_arm64-v8a.so";
+
+// https://github.com/asivery/xovi-rmfakecloud/blob/main/src/commons.cpp#L47
+static const QSet<QString> &patchableHosts() {
+    static const QSet<QString> hosts = {
+        QStringLiteral("hwr-production-dot-remarkable-production.appspot.com"),
+        QStringLiteral("service-manager-production-dot-remarkable-production.appspot.com"),
+        QStringLiteral("local.appspot.com"),
+        QStringLiteral("my.remarkable.com"),
+        QStringLiteral("ping.remarkable.com"),
+        QStringLiteral("internal.cloud.remarkable.com"),
+        QStringLiteral("eu.tectonic.remarkable.com"),
+        QStringLiteral("backtrace-proxy.cloud.remarkable.engineering"),
+        QStringLiteral("dev.ping.remarkable.com"),
+        QStringLiteral("dev.tectonic.remarkable.com"),
+        QStringLiteral("dev.internal.cloud.remarkable.com"),
+        QStringLiteral("eu.internal.tctn.cloud.remarkable.com"),
+        QStringLiteral("webapp-prod.cloud.remarkable.engineering"),
+    };
+    return hosts;
+}
+
 static bool shouldPatchURL(const QString &host) {
     if (host.isEmpty()) {
         return false;
     }
+    return patchableHosts().contains(host.toLower());
+}
 
-    return QString(R"""(
+static QNetworkRequest maybeRedirect(const QNetworkRequest &req) {
-        hwr-production-dot-remarkable-production.appspot.com
+    const QString host = req.url().host();
-        service-manager-production-dot-remarkable-production.appspot.com
+    if (!shouldPatchURL(host)) {
-        local.appspot.com
+        return req;
-        my.remarkable.com
+    }
-        ping.remarkable.com
+
-        internal.cloud.remarkable.com
+    const HookConfig cfg = getConfiguration();
-        eu.tectonic.remarkable.com
+    if (!cfg.isValid()) {
-        backtrace-proxy.cloud.remarkable.engineering
+        LOGW("Skipping redirect for %s: no valid configuration", host.toStdString().c_str());
-        dev.ping.remarkable.com
+        return req;
-        dev.tectonic.remarkable.com
+    }
-        dev.internal.cloud.remarkable.com
+
-        eu.internal.tctn.cloud.remarkable.com
+    QNetworkRequest newReq(req);
-        webapp-prod.cloud.remarkable.engineering
+    QUrl newUrl = req.url();
-    )""")
+    newUrl.setHost(cfg.host);
-        .contains(host, Qt::CaseInsensitive);
+    newUrl.setPort(cfg.port);
+    newReq.setUrl(newUrl);
+    return newReq;
 }
 
 // QObject *QNetworkAccessManager::createRequest(Operation op, const QNetworkRequest &req, QIODevice *outgoingData)
@@ -64,25 +92,12 @@ QNetworkReply* hooked_qNetworkAccessManager_createRequest(
     const QNetworkRequest& req,
     QIODevice* outgoingData
 ) {
-    LOGI("createRequest called for URL: %s", req.url().toString().toStdString().c_str());
+    LOGI("createRequest called for host: %s", req.url().host().toStdString().c_str());
-    const QString host = req.url().host();
-    if (shouldPatchURL(host)) {
-        QNetworkRequest newReq(req);
-        QUrl newUrl = req.url();
-        newUrl.setHost(gConfiguredHost);
-        newUrl.setPort(gConfiguredPort);
-        newReq.setUrl(newUrl);
 
-        if (original_qNetworkAccessManager_createRequest) {
+    if (!original_qNetworkAccessManager_createRequest) {
-            return original_qNetworkAccessManager_createRequest(self, op, newReq, outgoingData);
-        }
         return nullptr;
     }
-
+    return original_qNetworkAccessManager_createRequest(self, op, maybeRedirect(req), outgoingData);
-    if (original_qNetworkAccessManager_createRequest) {
-        return original_qNetworkAccessManager_createRequest(self, op, req, outgoingData);
-    }
-    return nullptr;
 }
 
 // void QWebSocket::open(const QNetworkRequest &req)
@@ -110,25 +125,30 @@ void hooked_qWebSocket_open(
     QWebSocket* self,
     const QNetworkRequest& req
 ) {
-    LOGI("QWebSocket::open called for URL: %s", req.url().toString().toStdString().c_str());
+    LOGI("QWebSocket::open called for host: %s", req.url().host().toStdString().c_str());
+
     if (!original_qWebSocket_open) {
         return;
     }
-
+    original_qWebSocket_open(self, maybeRedirect(req));
-    const QString host = req.url().host();
-    if (shouldPatchURL(host)) {
-        QUrl newUrl = req.url();
-        newUrl.setHost(gConfiguredHost);
-        newUrl.setPort(gConfiguredPort);
-
-        QNetworkRequest newReq(req);
-        newReq.setUrl(newUrl);
-
-        original_qWebSocket_open(self, newReq);
-        return;
 }
 
-    original_qWebSocket_open(self, req);
+static bool hookSymbol(const char *library, const char *symbol, const char *label,
+                        void *replacement, void **originalOut) {
+    void *address = resolve_qt_symbol(library, symbol);
+    if (!address) {
+        LOGE("Skipping hook for %s: symbol not found", label);
+        return false;
+    }
+
+    void *stub = shadowhook_hook_sym_addr(address, replacement, originalOut);
+    if (!stub) {
+        LOGE("Failed to hook %s: %s", label, shadowhook_to_errmsg(shadowhook_get_errno()));
+        return false;
+    }
+
+    LOGI("Hooked %s", label);
+    return true;
 }
 
 static void install_hooks() {
@@ -141,39 +161,21 @@ static void install_hooks() {
         return;
     }
 
-    // Hook QNetworkAccessManager::createRequest
+    hookSymbol(
-    void *create_request = resolve_qt_symbol(
+        kLibQtNetwork,
-        "libQt6Network_arm64-v8a.so",
+        "_ZN21QNetworkAccessManager13createRequestENS_9OperationERK15QNetworkRequestP9QIODevice",
-        "_ZN21QNetworkAccessManager13createRequestENS_9OperationERK15QNetworkRequestP9QIODevice");
+        "createRequest",
-    void *stub1 = shadowhook_hook_sym_addr(
-        create_request,
         (void *)hooked_qNetworkAccessManager_createRequest,
         (void **)&original_qNetworkAccessManager_createRequest);
 
-    if (stub1 != nullptr) {
+    hookSymbol(
-        LOGI("Hooked createRequest");
+        kLibQtWebSockets,
-    } else {
+        "_ZN10QWebSocket4openERK15QNetworkRequest",
-        LOGE("Failed to hook createRequest: %s",
+        "QWebSocket::open",
-             shadowhook_to_errmsg(shadowhook_get_errno()));
-    }
-
-    // Hook QWebSocket::open
-    void *websocket_open = resolve_qt_symbol(
-        "libQt6WebSockets_arm64-v8a.so",
-        "_ZN10QWebSocket4openERK15QNetworkRequest");
-    void *stub2 = shadowhook_hook_sym_addr(
-        websocket_open,
         (void *)hooked_qWebSocket_open,
         (void **)&original_qWebSocket_open);
 
-    if (stub2 != nullptr) {
+    LOGI("Hook installation finished");
-        LOGI("Hooked QWebSocket::open");
-    } else {
-        LOGE("Failed to hook QWebSocket::open: %s",
-             shadowhook_to_errmsg(shadowhook_get_errno()));
-    }
-
-    LOGI("All hooks active");
 }
 
 extern "C" void startHooks() {