refactor: code hardening

.clang-format

@@ -6,3 +6,5 @@ IndentCaseLabels: true
 ColumnLimit: 120
 PointerAlignment: Right
 AllowShortFunctionsOnASingleLine: None
+InsertBraces: true
+AllowShortBlocksOnASingleLine: Empty

README.md

@@ -1,63 +1,63 @@
-# tgbot
-
-A minimal C Telegram API Framework.
-
-## Requirements
-
-- libcurl
-- json-c
-
-> Note: This project is purely educational. It does not aim to cover the entire Telegram Bot API, but only a selected subset of methods.
-
-## How to build
-
-<details>
-
-<summary>Linux</summary>
-
-```bash
-$ meson setup build
-$ cd build
-$ meson compile
-$ meson install
-```
-
-</details>
-
-<details>
-
-<summary>Windows</summary>
-
-Install all the required library with `vcpkg` and then copy the DLL file.
-
-```powershell
-$ meson setup build --native-file meson-vcpkg.txt
-$ cd build
-$ meson compile
-$ meson install
-```
-
-</details>
-
-## Examples
-
-You can find some examples [here](./examples/).
-
-### Supported Types
-
-- **InlineKeyboardMarkup**
-  - Note: Standard `KeyboardMarkup` is intentionally not supported.
-
-#### Supported Methods
-
-- `getMe`
-- `sendMessage`
-- `editMessageText`
-- `sendDice`
-
-## Roadmap
-
-- `sendPhoto`
-- `sendAudio`
-- `sendDocument`
-- `sendVideo`
+# tgbot
+
+A minimal C Telegram API library.
+
+## Requirements
+
+- libcurl
+- json-c
+
+> Note: This project is purely educational. It does not aim to cover the entire Telegram Bot API, but only a selected subset of methods.
+
+## How to build
+
+<details>
+
+<summary>Linux</summary>
+
+```bash
+$ meson setup build
+$ cd build
+$ meson compile
+$ meson install
+```
+
+</details>
+
+<details>
+
+<summary>Windows</summary>
+
+Install all the required library with `vcpkg` and then copy the DLL file.
+
+```powershell
+$ meson setup build --native-file meson-vcpkg.txt
+$ cd build
+$ meson compile
+$ meson install
+```
+
+</details>
+
+## Examples
+
+You can find some examples [here](./examples/).
+
+### Supported Types
+
+- **InlineKeyboardMarkup**
+    - Note: Standard `KeyboardMarkup` is intentionally not supported.
+
+#### Supported Methods
+
+- `getMe`
+- `sendMessage`
+- `editMessageText`
+- `sendDice`
+- `sendPhoto`
+
+## Roadmap
+
+- `sendAudio`
+- `sendDocument`
+- `sendVideo`

examples/sender/sendpic.c

@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <tgbot/methods.h>
+#include <tgbot/tgbot.h>
+#include <tgbot/types.h>
+
+#define START_MESSAGE "Send /photo to receive a nice landscape!"
+#define PHOTO_PATH "my_photo.jpg"
+
+int main(void) {
+	FILE *tok = fopen(".token", "r");
+	if (!tok) {
+		exit(EXIT_FAILURE);
+	}
+
+	char token[512];
+	fscanf(tok, "%s", token);
+	fprintf(stdout, "Token: %s\n", token);
+
+	tgbot_s *bot = tgbot_new(token);
+	if (!bot) {
+		return -1;
+	}
+
+	tgbot_update_s update;
+	while (1) {
+		tgbot_get_update(bot, &update, NULL);
+
+		if (!strcmp(update.text, "/start")) {
+			tgbot_send_message(bot, update.chat_id, START_MESSAGE, "MARKDOWN", NULL);
+		} else if (!strcmp(update.text, "/photo")) {
+			tgbot_send_photo(bot, update.chat_id, PHOTO_PATH, "Mountains!");
+		}
+	}
+
+	return 0;
+}

include/methods.h

@@ -2,7 +2,6 @@
 #define TGBOT_METHODS_H
 
 #include "types.h"
-#include <json-c/json.h>
 
 /* Retrieve update */
 int tgbot_get_update(tgbot_s *bot, tgbot_update_s *update, Callback cbq_handler);
@@ -12,6 +11,7 @@ int tgbot_get_me(const tgbot_s *bot, tgbot_me_s *me);
 int tgbot_send_message(const tgbot_s *bot, int64_t chat_id, const char *text, const char *parse_mode,
 					   tgbot_inlinekeyboard_s *reply_markup);
 int tgbot_send_dice(const tgbot_s *bot, int64_t chat_id, const char *emoji);
+int tgbot_send_photo(const tgbot_s *bot, int64_t chat_id, const char *path, const char *caption);
 
 /* Updating Methods */
 int tgbot_edit_message_text(const tgbot_s *bot, int64_t chat_id, long message_id, const char *text,

include/tgbot.h

@@ -15,6 +15,8 @@ tgbot_s *tgbot_new(const char *token);
 
 /**
  * @brief Cleans the memory.
+ * Note: If you're using curl it will call curl_global_cleanup().
+ * Maybe I'll change the API.
  *
  * @param[out] bot The Bot object.
  */

meson-vcpkg.txt

@@ -1,28 +0,0 @@
-[constants]
-vcpkg_base_path = 'C:/vcpkg/'
-vcpkg_base_install_dir = 'C:/vcpkg/installed/'
-
-vcpkg_target_triplet = 'x64-windows'
-vcpkg_host_triplet = 'x64-windows'
-
-vcpkg_installed_dir =  vcpkg_base_install_dir + vcpkg_target_triplet + '/'
-vcpkg_host_installed_dir = vcpkg_base_install_dir + vcpkg_host_triplet + '/'
-vcpkg_toolchain_file =  vcpkg_base_path + 'scripts/toolchains/windows.cmake'
-
-[properties]
-cmake_toolchain_file = vcpkg_base_path + 'scripts/buildsystems/vcpkg.cmake'
-
-[binaries]
-vcpkg = [ vcpkg_base_path + 'vcpkg.exe']
-pkgconfig = [ vcpkg_installed_dir + 'tools/pkgconf/pkgconf.exe']
-
-[cmake]
-VCPKG_TARGET_TRIPLET = vcpkg_target_triplet
-VCPKG_HOST_TRIPLET = vcpkg_host_triplet
-VCPKG_CHAINLOAD_TOOLCHAIN_FILE = vcpkg_base_path + 'scripts/toolchains/windows.cmake'
-_VCPKG_INSTALLED_DIR = vcpkg_installed_dir
-VCPKG_CRT_LINKAGE = 'dynamic'
-
-[built-in options]
-pkg_config_path =  [ vcpkg_installed_dir + 'lib/pkgconfig;' + vcpkg_installed_dir + 'share/pkgconfig']
-cmake_prefix_path = [ vcpkg_installed_dir ]

meson.build

@@ -39,12 +39,32 @@ tgbot_dep = declare_dependency(
     dependencies: deps,
 )
 
+cppcheck = find_program('cppcheck', required: false)
+if cppcheck.found()
+    run_target(
+        'cppcheck',
+        command: [
+            cppcheck,
+            '--enable=all',
+            '--inconclusive',
+            '--std=c18',
+            '--check-level=exhaustive',
+            '--suppress=missingIncludeSystem',
+            '--project='
+            + join_paths(meson.current_build_dir(), 'compile_commands.json'),
+        ],
+    )
+endif
+
+clangformat = find_program('clang-format', required: false)
+if clangformat.found()
+    run_target('format', command: [clangformat, '-i', sources])
+endif
+
 # Example
-example = executable(
+executable(
     'example',
-    'examples/inlinekeyboard/inlinekeyboard.c',
+    'examples/sender/sendpic.c',
     dependencies: tgbot_dep,
     build_by_default: false,
 )
-
-test('example_inlinekeyboard', example)

src/internal/common.h

@@ -23,7 +23,7 @@ struct memory_buffer {
 typedef struct tgbot {
 	char token[TOKEN_SIZE]; /**< Bot token. */
 	char api[API_SIZE];		/**< Bot API url. */
-	int32_t offset;			/**< Bot offset. */
+	int64_t offset;			/**< Bot offset. */
 } tgbot_s;
 
 enum tgbot_opt_type {

src/json.c

@@ -6,6 +6,10 @@
 #include "tg_types.h"
 
 json_object *json_builder(tgbot_option_s *options, size_t optionslen) {
+	if (!options && optionslen > 0) {
+		return NULL;
+	}
+
 	json_object *rjson = json_object_new_object();
 	if (!rjson) {
 		return NULL;
@@ -14,6 +18,9 @@ json_object *json_builder(tgbot_option_s *options, size_t optionslen) {
 	for (size_t i = 0; i < optionslen; ++i) {
 		switch (options[i].type) {
 			case tgbot_opt_int: {
+				if (!options[i].value) {
+					break;
+				}
 				json_object_object_add(rjson, options[i].key, json_object_new_int(*((int32_t *)options[i].value)));
 				break;
 			}
@@ -25,12 +32,19 @@ json_object *json_builder(tgbot_option_s *options, size_t optionslen) {
 				break;
 			}
 			case tgbot_opt_int64: {
+				if (!options[i].value) {
+					break;
+				}
 				json_object_object_add(rjson, options[i].key, json_object_new_int64(*((int64_t *)options[i].value)));
 				break;
 			}
 			case tgbot_opt_inlinekeyboard: {
 				if (options[i].value != NULL) {
 					json_object *reply_markup = json_ikb_new((tgbot_inlinekeyboard_s *)options[i].value);
+					if (!reply_markup) {
+						json_object_put(rjson);
+						return NULL;
+					}
 					json_object_object_add(rjson, options[i].key, reply_markup);
 				}
 				break;
@@ -45,6 +59,10 @@ json_object *json_builder(tgbot_option_s *options, size_t optionslen) {
 }
 
 json_object *json_ikb_new(tgbot_inlinekeyboard_s *keyboard) {
+	if (!keyboard) {
+		return NULL;
+	}
+
 	json_object *reply_markup = json_object_new_object();
 	if (!reply_markup) {
 		return NULL;
@@ -58,9 +76,15 @@ json_object *json_ikb_new(tgbot_inlinekeyboard_s *keyboard) {
 
 	for (size_t i = 0; i < keyboard->rows; ++i) {
 		json_object *row = json_object_new_array();
+		if (!row) {
+			json_object_put(inline_keyboard_array);
+			json_object_put(reply_markup);
+			return NULL;
+		}
+
 		for (size_t j = 0; j < keyboard->columns; ++j) {
 			tgbot_inlinekeyboardbutton_s *kbbutton = tgbot_inlinekb_button_at(keyboard, i, j);
-			if (strcmp(kbbutton->text, "") == 0) {
+			if (!kbbutton || kbbutton->text[0] == '\0') {
 				continue;
 			}
 
@@ -70,8 +94,12 @@ json_object *json_ikb_new(tgbot_inlinekeyboard_s *keyboard) {
 			}
 
 			json_object_object_add(button, "text", json_object_new_string(kbbutton->text));
-			json_object_object_add(button, "url", json_object_new_string(kbbutton->url));
-			json_object_object_add(button, "callback_data", json_object_new_string(kbbutton->callback_data));
+			if (kbbutton->url[0] != '\0') {
+				json_object_object_add(button, "url", json_object_new_string(kbbutton->url));
+			}
+			if (kbbutton->callback_data[0] != '\0') {
+				json_object_object_add(button, "callback_data", json_object_new_string(kbbutton->callback_data));
+			}
 
 			json_object_array_add(row, button);
 		}

src/methods.c

@@ -58,7 +58,7 @@ static int tgbot_request(const char *url, struct memory_buffer **mb, json_object
 	}
 
 	curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 1L);
-	curl_easy_setopt(curl, CURLOPT_TCP_KEEPALIVE, 30L);
+	curl_easy_setopt(curl, CURLOPT_TCP_KEEPALIVE, 1L);
 
 	if (json != NULL) {
 		json_string = json_object_to_json_string_ext(json, JSON_C_TO_STRING_PLAIN);
@@ -96,6 +96,60 @@ static int tgbot_execute_method(const tgbot_s *bot, const char *method, tgbot_op
 	return ret;
 }
 
+static int tgbot_execute_method_multipart(const tgbot_s *bot, const char *method, int64_t chat_id, const char *path,
+										  const char *caption) {
+	CURL *curl = curl_easy_init();
+	if (!curl) {
+		return -1;
+	}
+
+	char url[URL_LEN] = {0};
+	int chars = snprintf(url, sizeof(url), "%s%s", bot->api, method);
+	if (chars < 0 || (size_t)chars >= sizeof(url)) {
+		curl_easy_cleanup(curl);
+		return -1;
+	}
+
+	curl_mime *mime = curl_mime_init(curl);
+	curl_mimepart *part;
+
+	char chat_id_str[512];
+	snprintf(chat_id_str, sizeof chat_id_str, "%ld", chat_id);
+
+	part = curl_mime_addpart(mime);
+	curl_mime_data(part, chat_id_str, CURL_ZERO_TERMINATED);
+	curl_mime_name(part, "chat_id");
+
+	part = curl_mime_addpart(mime);
+	curl_mime_filedata(part, path);
+	curl_mime_name(part, "photo");
+
+	part = curl_mime_addpart(mime);
+	curl_mime_data(part, caption, CURL_ZERO_TERMINATED);
+	curl_mime_name(part, "caption");
+
+	curl_easy_setopt(curl, CURLOPT_URL, url);
+	curl_easy_setopt(curl, CURLOPT_MIMEPOST, mime);
+
+	/* Do not print response to output */
+	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, discard_callback);
+	curl_easy_setopt(curl, CURLOPT_WRITEDATA, NULL);
+
+	CURLcode res = curl_easy_perform(curl);
+	if (res != CURLE_OK) {
+		fprintf(stderr, "curl_easy_perform: %s\n", curl_easy_strerror(res));
+		curl_easy_cleanup(curl);
+		curl_mime_free(mime);
+
+		return -1;
+	}
+
+	curl_easy_cleanup(curl);
+	curl_mime_free(mime);
+
+	return 0;
+}
+
 int tgbot_get_update(tgbot_s *bot, tgbot_update_s *update, Callback cbq_handler) {
 	char url[URL_LEN];
 
@@ -163,11 +217,13 @@ int tgbot_get_me(const tgbot_s *bot, tgbot_me_s *me) {
 	char url[URL_LEN];
 	snprintf(url, sizeof(url), "%sgetMe", bot->api);
 
-	struct memory_buffer *mb;
+	struct memory_buffer *mb = {0};
 	int ret = tgbot_request(url, &mb, NULL);
 	if (ret != 0) {
-		free(mb->data);
-		free(mb);
+		if (mb) {
+			free(mb->data);
+			free(mb);
+		}
 
 		return -1;
 	}
@@ -185,10 +241,14 @@ int tgbot_get_me(const tgbot_s *bot, tgbot_me_s *me) {
 
 	const json_object *result = json_object_object_get(json, "result");
 	json_object *first_name = json_object_object_get(result, "first_name");
-	snprintf(me->first_name, sizeof(me->first_name), "%s", json_object_get_string(first_name));
+	if (first_name) {
+		snprintf(me->first_name, sizeof(me->first_name), "%s", json_object_get_string(first_name));
+	}
 
 	json_object *username = json_object_object_get(result, "username");
-	snprintf(me->username, sizeof(me->username), "%s", json_object_get_string(username));
+	if (username) {
+		snprintf(me->username, sizeof(me->username), "%s", json_object_get_string(username));
+	}
 
 	json_object_put(json);
 
@@ -196,12 +256,12 @@ int tgbot_get_me(const tgbot_s *bot, tgbot_me_s *me) {
 }
 
 int tgbot_send_message(const tgbot_s *bot, int64_t chat_id, const char *text, const char *parse_mode,
-					   tgbot_inlinekeyboard_s *keyboard) {
+					   tgbot_inlinekeyboard_s *reply_markup) {
 	tgbot_option_s options[4] = {
 		{"chat_id", &chat_id, tgbot_opt_int64},
 		{"text", (void *)text, tgbot_opt_string},
 		{"parse_mode", (void *)parse_mode, tgbot_opt_string},
-		{"reply_markup", keyboard, tgbot_opt_inlinekeyboard},
+		{"reply_markup", reply_markup, tgbot_opt_inlinekeyboard},
 	};
 
 	return tgbot_execute_method(bot, "sendMessage", options, opt_size(options));
@@ -227,3 +287,7 @@ int tgbot_send_dice(const tgbot_s *bot, int64_t chat_id, const char *emoji) {
 
 	return tgbot_execute_method(bot, "sendDice", options, opt_size(options));
 }
+
+int tgbot_send_photo(const tgbot_s *bot, int64_t chat_id, const char *path, const char *caption) {
+	return tgbot_execute_method_multipart(bot, "sendPhoto", chat_id, path, caption);
+}

src/parse.c

@@ -2,41 +2,56 @@
 #include "internal/common.h"
 
 int tgbot_parse_message(tgbot_s *bot, tgbot_update_s *update, json_object *result) {
+	if (!bot || !update || !result) {
+		return -1;
+	}
+
 	json_object *update_id = json_object_object_get(result, "update_id");
+	if (!update_id) {
+		return -1;
+	}
+
 	bot->offset = json_object_get_int(update_id) + 1;
 	update->update_id = json_object_get_int(update_id);
 
 	json_object *message = json_object_object_get(result, "message");
+	if (!message) {
+		return -1;
+	}
+
 	json_object *message_id = json_object_object_get(message, "message_id");
 	if (message_id) {
-		update->message_id = json_object_get_int(message_id);
+		update->message_id = json_object_get_int64(message_id);
 	}
 
 	json_object *chat = json_object_object_get(message, "chat");
-	json_object *chat_id = json_object_object_get(chat, "id");
-	if (chat_id) {
-		update->chat_id = json_object_get_int64(chat_id);
-	}
+	if (chat) {
+		json_object *chat_id = json_object_object_get(chat, "id");
+		if (chat_id) {
+			update->chat_id = json_object_get_int64(chat_id);
+		}
 
-	json_object *chat_first_name = json_object_object_get(chat, "first_name");
-	if (chat_first_name) {
-		snprintf(update->chat_first_name, sizeof(update->chat_first_name), "%s",
-				 json_object_get_string(chat_first_name));
-	}
+		json_object *chat_first_name = json_object_object_get(chat, "first_name");
+		if (chat_first_name) {
+			snprintf(update->chat_first_name, sizeof(update->chat_first_name), "%s",
+					 json_object_get_string(chat_first_name));
+		}
 
-	json_object *chat_last_name = json_object_object_get(chat, "last_name");
-	if (chat_last_name) {
-		snprintf(update->chat_last_name, sizeof(update->chat_last_name), "%s", json_object_get_string(chat_last_name));
-	}
+		json_object *chat_last_name = json_object_object_get(chat, "last_name");
+		if (chat_last_name) {
+			snprintf(update->chat_last_name, sizeof(update->chat_last_name), "%s",
+					 json_object_get_string(chat_last_name));
+		}
 
-	json_object *chat_username = json_object_object_get(chat, "username");
-	if (chat_username != NULL) {
-		snprintf(update->chat_username, sizeof(update->chat_username), "%s", json_object_get_string(chat_username));
-	}
+		json_object *chat_username = json_object_object_get(chat, "username");
+		if (chat_username) {
+			snprintf(update->chat_username, sizeof(update->chat_username), "%s", json_object_get_string(chat_username));
+		}
 
-	json_object *chat_type = json_object_object_get(chat, "type");
-	if (chat_type) {
-		snprintf(update->chat_type, sizeof(update->chat_type), "%s", json_object_get_string(chat_type));
+		json_object *chat_type = json_object_object_get(chat, "type");
+		if (chat_type) {
+			snprintf(update->chat_type, sizeof(update->chat_type), "%s", json_object_get_string(chat_type));
+		}
 	}
 
 	json_object *date = json_object_object_get(message, "date");
@@ -53,26 +68,44 @@ int tgbot_parse_message(tgbot_s *bot, tgbot_update_s *update, json_object *resul
 }
 
 int tgbot_parse_cbquery(tgbot_s *bot, tgbot_cbquery_s *query, json_object *result, Callback cbq_handler) {
+	if (!bot || !query || !result || !cbq_handler) {
+		return -1;
+	}
+
 	json_object *update_id = json_object_object_get(result, "update_id");
+	if (!update_id) {
+		return -1;
+	}
+
 	bot->offset = json_object_get_int(update_id) + 1;
 	query->update_id = json_object_get_int(update_id);
 
 	json_object *callback_query = json_object_object_get(result, "callback_query");
+	if (!callback_query) {
+		return -1;
+	}
+
 	json_object *message = json_object_object_get(callback_query, "message");
+	if (!message) {
+		return -1;
+	}
+
 	json_object *message_id = json_object_object_get(message, "message_id");
 	if (message_id) {
-		query->message_id = json_object_get_int(message_id);
+		query->message_id = json_object_get_int64(message_id);
 	}
 
 	json_object *chat = json_object_object_get(message, "chat");
-	json_object *chat_id = json_object_object_get(chat, "id");
-	if (chat_id) {
-		query->chat_id = json_object_get_int64(chat_id);
-	}
+	if (chat) {
+		json_object *chat_id = json_object_object_get(chat, "id");
+		if (chat_id) {
+			query->chat_id = json_object_get_int64(chat_id);
+		}
 
-	json_object *chat_username = json_object_object_get(chat, "username");
-	if (chat_username) {
-		snprintf(query->chat_username, sizeof(query->chat_username), "%s", json_object_get_string(chat_username));
+		json_object *chat_username = json_object_object_get(chat, "username");
+		if (chat_username) {
+			snprintf(query->chat_username, sizeof(query->chat_username), "%s", json_object_get_string(chat_username));
+		}
 	}
 
 	json_object *date = json_object_object_get(message, "date");

src/tgbot.c

@@ -8,21 +8,44 @@
 #include "tgbot.h"
 
 tgbot_s *tgbot_new(const char *token) {
+	if (!token || token[0] == '\0') {
+		return NULL;
+	}
+
 	tgbot_s *bot = malloc(sizeof(tgbot_s));
 	if (!bot) {
 		return NULL;
 	}
 
-	curl_global_init(CURL_GLOBAL_DEFAULT);
+	if (curl_global_init(CURL_GLOBAL_DEFAULT) != CURLE_OK) {
+		free(bot);
+		return NULL;
+	}
+
+	int chars = snprintf(bot->api, sizeof(bot->api), "https://api.telegram.org/bot%s/", token);
+	if (chars < 0 || (size_t)chars >= sizeof(bot->api)) {
+		curl_global_cleanup();
+		free(bot);
+		return NULL;
+	}
+
+	chars = snprintf(bot->token, sizeof(bot->token), "%s", token);
+	if (chars < 0 || (size_t)chars >= sizeof(bot->token)) {
+		curl_global_cleanup();
+		free(bot);
+		return NULL;
+	}
 
-	snprintf(bot->api, sizeof(bot->api), "https://api.telegram.org/bot%s/", token);
-	snprintf(bot->token, sizeof(bot->token), "%s", token);
 	bot->offset = 0;
 
 	return bot;
 }
 
 void tgbot_free(tgbot_s *bot) {
+	if (!bot) {
+		return;
+	}
+
 	curl_global_cleanup();
 	free(bot);
 }

src/types.c

@@ -1,44 +1,62 @@
+#include <stdint.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "types.h"
 
 tgbot_inlinekeyboard_s *tgbot_inlinekb_new(size_t rows, size_t columns) {
-	tgbot_inlinekeyboard_s *keyboard = (tgbot_inlinekeyboard_s *)malloc(sizeof(tgbot_inlinekeyboard_s));
+	if (rows == 0 || columns == 0 || rows > SIZE_MAX / columns) {
+		return NULL;
+	}
+
+	tgbot_inlinekeyboard_s *keyboard = malloc(sizeof(tgbot_inlinekeyboard_s));
 	if (!keyboard) {
 		return NULL;
 	}
 
 	keyboard->rows = rows;
 	keyboard->columns = columns;
-	keyboard->buttons = (tgbot_inlinekeyboardbutton_s *)malloc(rows * columns * sizeof(tgbot_inlinekeyboardbutton_s));
+
+	size_t count = rows * columns;
+	keyboard->buttons = malloc(count * sizeof(tgbot_inlinekeyboardbutton_s));
 	if (!keyboard->buttons) {
 		free(keyboard);
-
 		return NULL;
 	}
 
-	memset(keyboard->buttons, 0, rows * columns * sizeof(tgbot_inlinekeyboardbutton_s));
+	memset(keyboard->buttons, 0, count * sizeof(tgbot_inlinekeyboardbutton_s));
 
 	return keyboard;
 }
 
 void tgbot_inlinekb_free(tgbot_inlinekeyboard_s *keyboard) {
+	if (!keyboard) {
+		return;
+	}
+
 	free(keyboard->buttons);
 	free(keyboard);
 }
 
 tgbot_inlinekeyboardbutton_s *tgbot_inlinekb_button_at(tgbot_inlinekeyboard_s *keyboard, size_t row, size_t column) {
+	if (!keyboard || row >= keyboard->rows || column >= keyboard->columns) {
+		return NULL;
+	}
+
 	return &keyboard->buttons[row * keyboard->columns + column];
 }
 
 int tgbot_inlinekb_button(tgbot_inlinekeyboard_s *keyboard, size_t row, size_t column, const char *text,
 						  const char *url, const char *callback_data) {
 	tgbot_inlinekeyboardbutton_s *button = tgbot_inlinekb_button_at(keyboard, row, column);
+	if (!button) {
+		return -1;
+	}
 
-	strncpy(button->text, text, sizeof(button->text) - 1);
-	strncpy(button->url, url, sizeof(button->url) - 1);
-	strncpy(button->callback_data, callback_data, sizeof(button->callback_data) - 1);
+	snprintf(button->text, sizeof(button->text), "%s", text ? text : "");
+	snprintf(button->url, sizeof(button->url), "%s", url ? url : "");
+	snprintf(button->callback_data, sizeof(button->callback_data), "%s", callback_data ? callback_data : "");
 
 	return 0;
 }