Add NK_device_info, NK_list_devices and NK_free_device_info

NK_list_devices corresponds to NitrokeyManager::list_devices.  It
returns a linked list of NK_device_info, which has to be freed using the
NK_free_device_info function.

2 files changed, 96 insertions, 0 deletions

diff --git a/NK_C_API.cc b/NK_C_API.cc
index f0c23a1..05457d0 100644
--- a/NK_C_API.cc
+++ b/NK_C_API.cc
@@ -736,6 +736,66 @@ NK_C_API char* NK_get_SD_usage_data_as_string() {
 		});
 	}
 
+	bool copy_device_info(const DeviceInfo& source, NK_device_info* target) {
+		switch (source.m_deviceModel) {
+		case DeviceModel::PRO:
+			target->model = NK_PRO;
+			break;
+		case DeviceModel::STORAGE:
+			target->model = NK_STORAGE;
+			break;
+		default:
+			return false;
+		}
+
+		target->path = strndup(source.m_path.c_str(), MAXIMUM_STR_REPLY_LENGTH);
+		target->serial_number = strndup(source.m_serialNumber.c_str(), MAXIMUM_STR_REPLY_LENGTH);
+		target->next = nullptr;
+
+		return target->path && target->serial_number;
+	}
+
+	NK_C_API struct NK_device_info* NK_list_devices() {
+		auto nm = NitrokeyManager::instance();
+		return get_with_result([&]() -> NK_device_info* {
+			auto v = nm->list_devices();
+			if (v.empty())
+				return nullptr;
+
+			auto result = new NK_device_info();
+			auto ptr = result;
+			auto first = v.begin();
+			if (!copy_device_info(*first, ptr)) {
+				NK_free_device_info(result);
+				return nullptr;
+			}
+			v.erase(first);
+
+			for (auto& info : v) {
+				ptr->next = new NK_device_info();
+				ptr = ptr->next;
+
+				if (!copy_device_info(info, ptr)) {
+					NK_free_device_info(result);
+					return nullptr;
+				}
+			}
+			return result;
+		});
+	}
+
+	NK_C_API void NK_free_device_info(struct NK_device_info* device_info) {
+		if (!device_info)
+			return;
+
+		if (device_info->next)
+			NK_free_device_info(device_info->next);
+
+		free(device_info->path);
+		free(device_info->serial_number);
+		delete device_info;
+	}
+
 	NK_C_API int NK_connect_with_ID(const char* id) {
 		auto m = NitrokeyManager::instance();
 		return get_with_result([&]() {
diff --git a/NK_C_API.h b/NK_C_API.h
index 81da956..f17098a 100644
--- a/NK_C_API.h
+++ b/NK_C_API.h
@@ -57,6 +57,29 @@ extern "C" {
             NK_STORAGE = 2
         };
 
+        /**
+	 * The connection info for a Nitrokey device as a linked list.
+	 */
+	struct NK_device_info {
+		/**
+		 * The model of the Nitrokey device.
+		 */
+		enum NK_device_model model;
+		/**
+		 * The USB device path for NK_connect_with_path.
+		 */
+		char* path;
+		/**
+		 * The serial number.
+		 */
+		char* serial_number;
+		/**
+		 * The pointer to the next element of the linked list or null
+		 * if this is the last element in the list.
+		 */
+		struct NK_device_info* next;
+	};
+
 	/**
 	 * Stores the status of a Storage device.
 	 */
@@ -768,6 +791,19 @@ extern "C" {
  */
 	NK_C_API char* NK_list_devices_by_cpuID();
 
+	/**
+	 * Returns a linked list of all connected devices, or null if no devices
+	 * are connected or an error occured.  The linked list must be freed by
+	 * calling NK_free_device_info.
+	 * @return a linked list of all connected devices
+	 */
+	NK_C_API struct NK_device_info* NK_list_devices();
+
+	/**
+	 * Free a linked list returned by NK_list_devices.
+	 * @param the linked list to free or null
+	 */
+	NK_C_API void NK_free_device_info(struct NK_device_info* device_info);
 
 /**
  * Connects to the device with given ID. ID's list could be created with NK_list_devices_by_cpuID.