Fix for indentation

.github/workflows/tests.yml

@@ -20,7 +20,7 @@ jobs:
       - name: "Build Tests"
         run: cmake --build build --target build-tests
       - name: "Run Tests"
-        run: ctest --build-dir build/Tests
+        run: ctest --test-dir build/Tests
   DevicetreeTests:
     runs-on: ubuntu-latest
     steps:

Buildscripts/DevicetreeCompiler/source/generator.py

@@ -282,7 +282,7 @@ def write_device_structs(file, device: Device, parent_device: Device, bindings:
     file.write(f"\t.address = {address_value},\n")
     file.write(f"\t.name = \"{device.node_name}\",\n") # Use original name
     file.write(f"\t.config = &{config_variable_name},\n")
-    file.write(f"\t.flags = DEVICE_FLAG_DTS,\n")
+    file.write("\t.flags = DEVICE_FLAG_DTS,\n")
     file.write(f"\t.parent = {parent_value},\n")
     file.write("\t.internal = NULL\n")
     file.write("};\n\n")

Buildscripts/DevicetreeCompiler/tests/data/expected_devicetree.c

@@ -13,6 +13,7 @@ static struct Device root = {
 	.address = 0,
 	.name = "/",
 	.config = &root_config,
+	.flags = DEVICE_FLAG_DTS,
 	.parent = NULL,
 	.internal = NULL
 };
@@ -27,6 +28,7 @@ static struct Device test_device = {
 	.address = 0,
 	.name = "test-device",
 	.config = &test_device_config,
+	.flags = DEVICE_FLAG_DTS,
 	.parent = &root,
 	.internal = NULL
 };
@@ -43,6 +45,7 @@ static struct Device bool_test_device = {
 	.address = 0,
 	.name = "bool-test-device",
 	.config = &bool_test_device_config,
+	.flags = DEVICE_FLAG_DTS,
 	.parent = &root,
 	.internal = NULL
 };

Devices/lilygo-tlora-pager/lilygo,tlora-pager.dts

@@ -11,6 +11,7 @@
 #include <tactility/bindings/esp32_sdspi.h>
 #include <tactility/bindings/esp32_pwm_ledc.h>
 #include <tactility/bindings/pwm_backlight.h>
+#include <gps_generic/bindings.h>
 #include <bindings/st7796.h>
 #include <bindings/bq27220.h>
 #include <bindings/tca8418.h>

Drivers/gps-generic-module/README.md

@@ -1,9 +1,10 @@
 # gps-generic-module
 
-Kernel driver implementing the `GPS_TYPE`/`GpsApi` interface (declared by `Drivers/gps-module`,
+Kernel driver implementing the `GPS_TYPE`/`GpsApi` interface with for generic UART-connected GPS/GNSS receivers:
-Apache-2.0) for generic UART-connected GPS/GNSS receivers: chipset probing, init sequences, and
 NMEA parsing for MTK, Airoha/AG33xx, ATGM336H/CASIC, Unicore UC6580 and u-blox 6/7/8/9/10 modules.
 
+It is ported from [Meshtastic Firmware](https://github.com/MeshTastic/firmware), so it has a GPL v3.0 license.
+
 ## License
 
 This module is licensed under **GPL-3.0-or-later** (see `LICENSE-GPL-3.0.md`), separately from

Drivers/gps-generic-module/source/gps_generic.cpp

@@ -18,7 +18,8 @@
 
 #include <minmea.h>
 
-#include <cstdlib>
+#include <cstdio>
+#include <cstdlib> // For calloc() in PC builds
 
 constexpr auto* TAG = "gps-generic";
 
@@ -315,7 +316,7 @@ static GpsState gps_api_get_state(Device* device) {
 static error_t gps_api_get_model_name(Device* device, char* model_name, size_t buffer_size) {
     const auto* config = GET_CONFIG(device);
     const char* name_to_set = gpsModelToString(config->model);
-    strncpy(model_name, name_to_set, buffer_size);
+    snprintf(model_name, buffer_size, "%s", name_to_set);
     return ERROR_NONE;
 }
 

LICENSE.md

@@ -7,13 +7,16 @@ These applications are not part of the Tactility operating system's main firmwar
 
 "end-users" refers to people who install and/or use Tactility software on their devices.
 
-## Past & Present
+## Summary
 
-Formerly, there was a mixed usage of [GPL v3.0](Documentation/LICENSE-GPL-3.0.md) for internal subprojects
+The main firmware projects (`Firmware/`, `Tactility/`) are licensed under [GPL v3.0](Documentation/LICENSE-GPL-3.0.md)
-and [Apache License v2.0](Documentation/LICENSE-Apache-2.0.md) for subprojects that would be used in external apps.
 
-For future subprojects, [Apache License v2.0](Documentation/LICENSE-Apache-2.0.md) will be chosen for internal subproject.
+Most drivers have an [Apache License v2.0](Documentation/LICENSE-Apache-2.0.md), with exceptions such as `Drivers/gps-generic-module/`.
-Existing GPL-licensed projects will retain this license, as it cannot be changed to a more permissive license.
+Licensing may also differ for subprojects intended for use in external applications.
+
+Specific aren't generally used directly in external app projects, but if they are, make sure to check their licenses.
+
+All projects under `Modules/` have an [Apache License v2.0](Documentation/LICENSE-Apache-2.0.md).
 
 ## Overview
 
@@ -22,13 +25,13 @@ Below is an overview of the licenses of some of the subprojects.
 | Project            | License                 |
 |--------------------|-------------------------|
 | Tactility          | GNU Public License v3.0 |
-| TactilityCore      | GNU Public License v3.0 |
 | TactilityC         | Apache License v2.0     |
 | TactilityFreeRTOS  | Apache License v2.0     |
 | TactilityKernel    | Apache License v2.0     |
 | Tests              | GNU Public License v3.0 |
 | Devices/*          | GNU Public License v3.0 |
 | Drivers/*          | (varies)                |
+| Modules/*          | Apache License v2.0     |
 | DevicetreeCompiler | Apache License v2.0     |
 | Platforms/*        | Apache License v2.0     |
 

Modules/gps-module/include/gps/gps.h

@@ -76,10 +76,27 @@ struct GpsSubscription {
  * @brief API for GPS/GNSS receiver drivers.
  */
 struct GpsApi {
+    /**
+     * @brief Registers a subscriber for GPS events (e.g. RMC/GGA sentences).
+     * @param[in] device the GPS device
+     * @param[in,out] sub subscription to register; caller owns the storage and must keep it alive until unsubscribed
+     */
     error_t (*event_subscribe)(struct Device* device, struct GpsSubscription* sub);
 
+    /**
+     * @brief Removes a previously registered subscription.
+     * @param[in] device the GPS device
+     * @param[in] sub subscription to remove, as passed to event_subscribe
+     */
     error_t (*event_unsubscribe)(struct Device* device, struct GpsSubscription* sub);
 
+    /**
+     * @brief Blocks the calling task until a new event arrives for the subscription, or timeout elapses.
+     * @param[in] device the GPS device
+     * @param[in,out] sub subscription to wait on
+     * @param[in] timeout max ticks to wait
+     * @return ERROR_NONE if an event arrived, ERROR_TIMEOUT if the timeout elapsed
+     */
     error_t (*event_await)(struct Device* device, struct GpsSubscription* sub, TickType_t timeout);
 
     /**
@@ -88,6 +105,13 @@ struct GpsApi {
      */
     enum GpsState (*get_state)(struct Device* device);
 
+    /**
+     * @brief Gets a human-readable model name for the device, e.g. "UBLOX8".
+     * @param[in] device the GPS device
+     * @param[out] model_name buffer to receive the NUL-terminated name
+     * @param[in] buffer_size size of model_name in bytes
+     * @return ERROR_NONE on success
+     */
     error_t (*get_model_name)(struct Device* device, char* model_name, size_t buffer_size);
 };
 
@@ -103,7 +127,7 @@ error_t gps_event_await(struct Device* device, struct GpsSubscription* sub, Tick
 /** @copydoc GpsApi::get_state */
 enum GpsState gps_get_state(struct Device* device);
 
-/** @copydoc GpsApi::get_state */
+/** @copydoc GpsApi::get_model_name */
 error_t gps_get_model_name(struct Device* device, char* model_name, size_t buffer_size);
 
 extern const struct DeviceType GPS_TYPE;

Modules/gps-module/source/gps_ledger.cpp

@@ -14,15 +14,7 @@
 
 constexpr auto* TAG = "gps_ledger";
 
-/**
- * @brief Configuration for a GPS_TYPE device.
- * @warning Mirrors gps-generic-module's own (GPL) GpsConfig field-for-field - this module can't
- * include that header (Apache/GPL boundary), so the layout has to be kept in sync by hand. uart is
- * left NULL here: this path uses device_set_parent() to the UART_CONTROLLER_TYPE device instead,
- * which the driver falls back to when config->uart is NULL.
- */
 struct GpsConfig {
-    Device* uart = nullptr;
     uint32_t baud_rate;
     enum GpsModel model;
 };

Modules/gps-module/source/gps_settings.cpp

@@ -2,7 +2,7 @@
 #include <gps/gps_settings.h>
 #include <gps/private/gps_ledger.h>
 
-#include <tactility/filesystem/file_lock.h>
+#include <tactility/filesystem/file_mutex.h>
 #include <tactility/log.h>
 #include <tactility/service/service_paths.h>
 
@@ -44,14 +44,23 @@ static bool get_configuration_path(char* out_path, size_t out_path_size) {
 // Holds the lock (if any) that `path` needs for the lifetime of the guard - see file_find_lock().
 class FileLockGuard {
     FileMutex mutex;
+    bool locked;
 public:
     explicit FileLockGuard(const char* path) {
-        file_get_mutex(path, &mutex);
+        file_mutex_get(&mutex, path);
-        file_lock(&mutex);
+        file_mutex_lock(&mutex);
+        locked = true;
     }
 
     ~FileLockGuard() {
-        file_unlock(&mutex);
+        unlock();
+    }
+
+    void unlock() {
+        if (locked) {
+            file_mutex_unlock(&mutex);
+            locked = false;
+        }
     }
 };
 
@@ -120,6 +129,7 @@ static error_t write_configurations(const std::vector<GpsConfiguration>& configu
         return ERROR_RESOURCE;
     }
 
+    lock.unlock();
     gps_ledger_sync();
 
     return ERROR_NONE;

Modules/lvgl-module/source/arch/lvgl_posix.c

@@ -39,10 +39,9 @@ static void task_unlock(void) {
     recursive_mutex_unlock(&task_mutex);
 }
 
-bool lvgl_lock(void) {
+void lvgl_lock(void) {
-    if (!lvgl_mutex_initialised) return false;
+    if (!lvgl_mutex_initialised) return;
     recursive_mutex_lock(&lvgl_mutex);
-    return true;
 }
 
 bool lvgl_try_lock(uint32_t timeout) {

Tactility/Include/Tactility/lvgl/LvglSync.h

@@ -14,11 +14,11 @@ constexpr TickType_t defaultLockTime = 500 / portTICK_PERIOD_MS;
  * @warning when passing zero, we wait forever, as this is the default behaviour for esp_lvgl_port, and we want it to remain consistent
  * @deprecated Use lvgl_lock() or lvgl_try_lock() from lvgl-module instead.
  */
-bool lock(TickType_t timeout = portMAX_DELAY) __attribute__((deprecated("Use file_get_mutex() from TactilityKernel")));
+bool lock(TickType_t timeout = portMAX_DELAY) __attribute__((deprecated("Use lvgl_lock() from lvgl-module")));
 
 /** @deprecated Use lvgl_unlock() from lvgl-module instead. */
-void unlock() __attribute__((deprecated("Use file_get_mutex() from TactilityKernel")));
+void unlock() __attribute__((deprecated("Use lvgl_unlock() from lvgl-module")));
 
-std::shared_ptr<Lock> getSyncLock() __attribute__((deprecated("Use file_get_mutex() from TactilityKernel")));
+std::shared_ptr<Lock> getSyncLock() __attribute__((deprecated("Use lvgl locking functions from lvgl-module")));
 
 } // namespace

Tactility/Private/Tactility/hal/SdCard.h

@@ -11,7 +11,7 @@ namespace tt::hal::sdcard {
  * Attempt to find an SD card that the specified belongs to,
  * and returns its lock if the SD card is mounted. Otherwise it returns nullptr.
  * @deprecated
- * @param[in] a path on a file system (e.g. file, directory, etc.)
+ * @param[in] path a path on a file system (e.g. file, directory, etc.)
  * @return the lock of a mounted SD card or otherwise null
  */
 std::shared_ptr<Lock> findSdCardLock(const std::string& path) __attribute__((deprecated("Use file_get_mutex() from TactilityKernel")));

Tactility/Source/Tactility.cpp

@@ -53,7 +53,7 @@ constexpr auto* TAG = "Tactility";
 
 static DispatcherHandle_t mainDispatcherHandle = dispatcher_alloc();
 
-void initFileLvglLock();
+void initFileMutexForLvgl();
 
 namespace {
 
@@ -374,16 +374,9 @@ void run(Module* dtsModules[], DtsDevice dtsDevices[]) {
         return;
     }
 
-    initFileLvglLock();
+    check(module_ensure_started(&crypt_module) == ERROR_NONE);
-
+    check(module_ensure_started(&gps_module) == ERROR_NONE);
-    // crypt-module
+    check(module_ensure_started(&gps_generic_module) == ERROR_NONE);
-    check(module_construct_add_start(&crypt_module) == ERROR_NONE);
-
-    // gps-module
-    check(module_construct_add_start(&gps_module) == ERROR_NONE);
-
-    // gps-generic-module
-    check(module_construct_add_start(&gps_generic_module) == ERROR_NONE);
 
 #ifdef ESP_PLATFORM
     initEsp();
@@ -402,6 +395,9 @@ void run(Module* dtsModules[], DtsDevice dtsDevices[]) {
 
     registerAndStartPrimaryServices();
 
+    // Must start right before LVGL
+    initFileMutexForLvgl();
+
     lvgl_module_configure((LvglModuleConfig) {
         .on_start = nullptr,
         .on_stop = nullptr,
@@ -414,8 +410,7 @@ void run(Module* dtsModules[], DtsDevice dtsDevices[]) {
         .task_affinity = getCpuAffinityConfiguration().graphics
 #endif
     });
-    check(module_construct_add_start(&lvgl_module) == ERROR_NONE);
+    check(module_ensure_started(&lvgl_module) == ERROR_NONE);
-    check(module_construct_add_start(&gps_module) == ERROR_NONE);
 
     registerAndStartSecondaryServices();
 

Tactility/Source/app/gpssettings/GpsSettings.cpp

@@ -274,14 +274,13 @@ public:
         // thread). Take the same lock updateDeviceStates() uses and hold it across the
         // free below, so the timer can never observe pendingDeleteDevice as a dangling
         // pointer in deviceRows.
-        auto lock = lvgl::getSyncLock()->asScopedLock();
+        lvgl_lock();
-        lock.lock();
-
         // Drop the stale row unconditionally (cheap vector op, no LVGL calls) - this is
         // what keeps the timer safe regardless of whether onShow() has run yet this cycle.
         std::erase_if(deviceRows, [this](const DeviceRow& row) {
             return row.device == pendingDeleteDevice;
         });
+        lvgl_unlock();
 
         // gps_settings_remove_configuration_at() frees the underlying Device synchronously -
         // do this only after the dangling pointer is already out of deviceRows.
@@ -291,9 +290,11 @@ public:
         // Only safe to touch deviceListWrapper if onShow() already built it for this show
         // cycle - it may not have run yet, in which case it'll rebuild fresh (post-deletion,
         // deviceRows already correct) when it does.
+        lvgl_lock();
         if (isShown) {
             rebuildDeviceList();
         }
+        lvgl_unlock();
     }
 };
 

Tactility/Source/file/FileMutexLvgl.cpp

@@ -1,10 +1,11 @@
 #include <tactility/device.h>
 #include <tactility/drivers/display.h>
 #include <tactility/drivers/spi_controller.h>
-#include <tactility/filesystem/file_lock.h>
+#include <tactility/filesystem/file_mutex.h>
 #include <tactility/filesystem/file_system.h>
 #include <tactility/lvgl_module.h>
 
+constexpr auto* TAG = "file_mutex_lvgl";
 
 struct Device;
 namespace tt {
@@ -19,28 +20,36 @@ static const FileMutex lvgl_mutex = {
  * Finds file systems with a device (e.g. sd card) that is owned by a SPI controller.
  * If the SPI controller has a display on the bus, we create an LVGL lock for the file system path.
  */
-void initFileLvglLock() {
+void initFileMutexForLvgl() {
     file_system_for_each(nullptr, [](FileSystem* fs, void* context) {
         char mount_path[64];
         if (file_system_get_path(fs, mount_path, sizeof(mount_path)) != ERROR_NONE) {
             return true;
         }
+        LOG_D(TAG, "Mount path %s", mount_path);
 
         // We only care about file system with a Device (owner)
         auto* owner = file_system_get_owner(fs);
         if (owner == nullptr) {
+            LOG_D(TAG, "Owner: none");
             return true;
         }
 
+        LOG_D(TAG, "Owner: %s", owner->name);
+
         // Ignore devices without a parent (root)
         auto* parent = device_get_parent(owner);
         if (parent == nullptr) {
+            LOG_D(TAG, "Owner: no parent");
             return true;
         }
 
+        LOG_D(TAG, "Owner: parent %s", parent->name);
+
         // If the FileSystem is on a SPI bus and there's more than 1 device, we assume the other one is the display.
         auto* type = device_get_type(parent);
         if (type != &SPI_CONTROLLER_TYPE || device_get_child_count(parent) <= 1) {
+            LOG_D(TAG, "Owner parent not SPI controller or not enough children");
             return true;
         }
 
@@ -49,21 +58,23 @@ void initFileLvglLock() {
         };
         Context ctx = { .mountPath = mount_path };
 
-        device_for_each_child(parent, &ctx, [](Device* child, void* context) {
+        device_for_each_child(parent, &ctx, [](Device* child, void* context) -> bool {
             Context* ctx = static_cast<Context*>(context);
             if (device_get_type(child) == &DISPLAY_TYPE) {
-                file_register_mutex(
+                LOG_I(TAG, "Adding file mutex for %s as it shares a bus with a display", ctx->mountPath);
-                    ctx->mountPath,
+                file_mutex_register(
-                    &lvgl_mutex
+                    &lvgl_mutex,
+                    ctx->mountPath
                 );
                 return false;
+            } else {
+                LOG_D(TAG, "child of parent, %s: not DISPLAY_TYPE", child->name);
             }
             return true;
         });
 
         return true;
     });
-
 }
 
 }

TactilityKernel/include/tactility/filesystem/file_lock.h

@@ -1,28 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-#pragma once
-
-#include <tactility/freertos/freertos.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-struct FileMutex {
-    void (*lock)();
-    bool (*try_lock)(TickType_t timeout);
-    void (*unlock)();
-};
-
-void file_register_mutex(const char* path, const FileMutex* mutex);
-
-void file_get_mutex(const char* path, struct FileMutex* mutex);
-
-void file_lock(struct FileMutex* mutex);
-
-bool file_try_lock(struct FileMutex* mutex, TickType_t timeout);
-
-void file_unlock(struct FileMutex* mutex);
-
-#ifdef __cplusplus
-}
-#endif

TactilityKernel/include/tactility/filesystem/file_mutex.h

@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+#include <tactility/freertos/freertos.h>
+
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Set of lock/try_lock/unlock callbacks backing a filesystem mount's mutex.
+ * Any field left null is treated as a no-op by file_mutex_lock/try_lock/unlock.
+ */
+struct FileMutex {
+    void (*lock)();
+    bool (*try_lock)(uint32_t timeout);
+    void (*unlock)();
+};
+
+/**
+ * @brief Registers a mutex for a mount path (e.g. "/sdcard") and its descendants.
+ * @param[in] mutex callbacks to associate with the path; a copy is stored
+ * @param[in] path mount path this mutex serializes access to
+ * @note No-op if a mutex is already registered for this exact path.
+ */
+void file_mutex_register(const struct FileMutex* mutex, const char* path);
+
+/**
+ * @brief Looks up the mutex registered for path or one of its ancestor mount paths.
+ * @param[out] mutex receives the matching mutex, or an all-null (no-op) mutex if none matches
+ * @param[in] path file or directory path to look up
+ */
+void file_mutex_get(struct FileMutex* mutex, const char* path);
+
+/** @brief Locks mutex. No-op if mutex->lock is null. */
+void file_mutex_lock(struct FileMutex* mutex);
+
+/**
+ * @brief Attempts to lock mutex within timeout.
+ * @return true if locked (or mutex->try_lock is null), false on timeout
+ */
+bool file_mutex_try_lock(struct FileMutex* mutex, TickType_t timeout);
+
+/** @brief Unlocks mutex. No-op if mutex->unlock is null. */
+void file_mutex_unlock(struct FileMutex* mutex);
+
+#ifdef __cplusplus
+}
+#endif

TactilityKernel/include/tactility/module.h

@@ -122,6 +122,22 @@ error_t module_stop(struct Module* module);
  */
 error_t module_construct_add_start(struct Module* module);
 
+/**
+ * @brief Tries to ensure the module is in a started state.
+ * Calls module_construct if needed, calls module_start if needed.
+ * @param module the module
+ * @return ERROR_NONE if module is in a started state
+ */
+error_t module_ensure_started(struct Module* module);
+
+/**
+ * @brief Tries to ensure the module is in a started state.
+ * Calls module_stop if needed, calls module_destruct if needed.
+ * @param module the module
+ * @return ERROR_NONE if module is in a destructed state
+ */
+error_t module_ensure_destructed(struct Module* module);
+
 /**
  * @brief Check if the module is started.
  * Can be used when module isn't constructed yet.

TactilityKernel/source/filesystem/file_mutex.cpp

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: Apache-2.0
-#include <tactility/filesystem/file_lock.h>
+#include <tactility/filesystem/file_mutex.h>
 
 #include <cstring>
 #include <string>
@@ -19,7 +19,8 @@ struct FileMutexEntry {
 static std::vector<FileMutexEntry> mutex_entries;
 
 extern "C" {
-void file_register_mutex(const char* path, const FileMutex* mutex) {
+
+void file_mutex_register(const FileMutex* mutex, const char* path) {
     // Skip if entry for path exists
     for (auto& entry : mutex_entries) {
         if (entry.path == path) {
@@ -34,31 +35,36 @@ void file_register_mutex(const char* path, const FileMutex* mutex) {
     });
 }
 
-void file_get_mutex(const char* path, FileMutex* mutex) {
+void file_mutex_get(FileMutex* mutex, const char* path) {
+    std::string path_string = path;
     for (auto& entry : mutex_entries) {
-        if (entry.path.rfind(path) == 0) {
+        // Match the mount path itself, or a descendant (e.g. "/sdcard" registered, "/sdcard/config.json" requested).
-            memcpy(mutex, &entry.mutex, sizeof(FileMutexEntry));
+        bool is_match = path_string == entry.path ||
+            (entry.path == "/" && !path_string.empty() && path_string[0] == '/') ||
+            (path_string.rfind(entry.path, 0) == 0 && path_string[entry.path.size()] == '/');
+        if (is_match) {
+            memcpy(mutex, &entry.mutex, sizeof(FileMutex));
             return;
         }
     }
 
-    memcpy(mutex, &no_mutex, sizeof(FileMutex));
+    *mutex = no_mutex;
 }
 
-void file_lock(FileMutex* mutex) {
+void file_mutex_lock(FileMutex* mutex) {
     if (mutex->lock) {
         mutex->lock();
     }
 }
 
-bool file_try_lock(FileMutex* mutex, TickType_t timeout) {
+bool file_mutex_try_lock(FileMutex* mutex, TickType_t timeout) {
     if (mutex->try_lock) {
         return mutex->try_lock(timeout);
     }
     return true;
 }
 
-void file_unlock(FileMutex* mutex) {
+void file_mutex_unlock(FileMutex* mutex) {
     if (mutex->unlock) {
         mutex->unlock();
     }

TactilityKernel/source/module.cpp

@@ -28,22 +28,39 @@ static ModuleLedger ledger;
 extern "C" {
 
 error_t module_construct(Module* module) {
+    if (module->internal != nullptr) {
+        LOG_E(TAG, "Module %s was already constructed", module->name);
+        return ERROR_INVALID_STATE;
+    }
     module->internal = new (std::nothrow) ModuleInternal();
     if (module->internal == nullptr) return ERROR_OUT_OF_MEMORY;
     return ERROR_NONE;
 }
 
 error_t module_destruct(Module* module) {
-    delete static_cast<ModuleInternal*>(module->internal);
+    if (module->internal == nullptr) {
+        LOG_E(TAG, "Module %s was already destructed", module->name);
+        return ERROR_INVALID_STATE;
+    }
+    delete module->internal;
     module->internal = nullptr;
     return ERROR_NONE;
 }
 
 error_t module_add(Module* module) {
     mutex_lock(&ledger.mutex);
-    ledger.modules.push_back(module);
+    bool exists = false;
+    for (auto* ledger_module : ledger.modules) {
+        if (ledger_module == module) {
+            exists = true;
+            break;
+        }
+    }
+    if (!exists) {
+        ledger.modules.push_back(module);
+    }
     mutex_unlock(&ledger.mutex);
-    return ERROR_NONE;
+    return exists ? ERROR_INVALID_STATE : ERROR_NONE;
 }
 
 error_t module_remove(Module* module) {
@@ -57,8 +74,8 @@ error_t module_start(Module* module) {
     LOG_I(TAG, "start %s", module->name);
 
     auto* internal = module->internal;
-    if (internal == nullptr) return ERROR_INVALID_STATE;
+    if (internal == nullptr) { return ERROR_INVALID_STATE; }
-    if (internal->started) return ERROR_NONE;
+    if (internal->started) { return ERROR_NONE; }
 
     if (module->start != nullptr) {
         auto error = module->start();
@@ -90,8 +107,8 @@ error_t module_stop(Module* module) {
     LOG_I(TAG, "stop %s", module->name);
 
     auto* internal = module->internal;
-    if (internal == nullptr) return ERROR_INVALID_STATE;
+    if (internal == nullptr) { return ERROR_INVALID_STATE; }
-    if (!internal->started) return ERROR_NONE;
+    if (!internal->started) { return ERROR_NONE; }
 
     if (module->drivers != nullptr && internal->drivers_ready) {
         size_t count = 0;
@@ -117,12 +134,41 @@ error_t module_stop(Module* module) {
 
 error_t module_construct_add_start(Module* module) {
     error_t error = module_construct(module);
-    if (error != ERROR_NONE) return error;
+    if (error != ERROR_NONE) { return error; }
     error = module_add(module);
-    if (error != ERROR_NONE) return error;
+    if (error != ERROR_NONE) { return error; }
     return module_start(module);
 }
 
+error_t module_ensure_started(Module* module) {
+    if (module->internal == nullptr) {
+        error_t result = module_construct(module);
+        if (result != ERROR_NONE) { return result; }
+    }
+
+    if (!module->internal->started) {
+        error_t result = module_start(module);
+        if (result != ERROR_NONE) { return result; }
+    }
+
+    return ERROR_NONE;
+}
+
+error_t module_ensure_destructed(Module* module) {
+    if (module->internal != nullptr) {
+        error_t result;
+        if (module->internal->started) {
+            result = module_stop(module);
+            if (result != ERROR_NONE) { return result; }
+        }
+
+        result = module_destruct(module);
+        if (result != ERROR_NONE) { return result; }
+    }
+
+    return ERROR_NONE;
+}
+
 bool module_resolve_symbol(Module* module, const char* symbol_name, uintptr_t* symbol_address) {
     if (!module_is_started(module)) return false;
     auto* symbol_ptr = module->symbols;