TCP input TLS - Add helper functions for throwing OpenSSL errors.

Author: BonnyAD9

src/plugins/input/tcp/src/tls/throw_ssl_err.hpp

@@ -0,0 +1,86 @@
+/**
+ * \file
+ * \author Jakub Antonín Štigler <[email protected]>
+ * \brief Helper functions for forming OpenSSL error messages. (header file)
+ * \date 2025
+ *
+ * Copyright: (C) 2023 CESNET, z.s.p.o.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#pragma once
+
+#include <array>
+#include <sstream>
+#include <string>
+
+#include <openssl/err.h>
+
+namespace tcp_in {
+namespace tls {
+
+/**
+ * @brief Throws exception with the given message appended with arguments and OpenSSL error message
+ * based on error code.
+ * @param code Error code of the OpenSSL message.
+ * @param msg Message describing the error.
+ */
+[[noreturn]]
+static void throw_ssl_err(int code, std::ostringstream msg) {
+    std::array<char, 256> err;
+    ERR_error_string_n(code, err.data(), err.size());
+    msg << err.data();
+
+    auto res = msg.str();
+    if (*res.rbegin() == '.') {
+        res.pop_back();
+        res += ": ";
+    }
+
+    throw std::runtime_error(res + err.data());
+}
+
+/**
+ * @brief Throws exception with the given message appended with arguments and OpenSSL error message
+ * based on error code.
+ * @param code Error code of the OpenSSL message.
+ * @param msg Partial message describing the error.
+ * @param arg Next argument to be appended to the message.
+ * @param args This will be converted to string and appended to the message.
+ */
+template<typename ARG, typename... ARGS>
+[[noreturn]]
+void throw_ssl_err(int code, std::ostringstream msg, ARG &&arg, ARGS &&...args) {
+    msg << arg;
+    throw_ssl_err(code, std::move(msg), std::forward<ARGS>(args)...);
+}
+
+/**
+ * @brief Throws exception with the given message appended with arguments and OpenSSL error message
+ * based on error code.
+ * @param code Error code of the OpenSSL message.
+ * @param what Message describing the error.
+ * @param args This will be converted to string and appended to the message.
+ */
+template<typename... ARGS>
+[[noreturn]]
+void throw_ssl_err(int code, const std::string &what, ARGS &&...args) {
+    std::ostringstream res;
+    res << what;
+    throw_ssl_err(code, std::move(res), std::forward<ARGS>(args)...);
+}
+
+/**
+ * @brief Throws exception with the given message appended with arguments and error message from top
+ * of the OpenSSL error stack. The error is popped from the error stack.
+ * @param what Message describing the error.
+ * @param args This will be converted to string and appended to the message.
+ */
+template<typename... ARGS>
+[[noreturn]]
+void throw_ssl_err(const std::string &what, ARGS &&...args) {
+    throw_ssl_err(ERR_get_error(), what, std::forward<ARGS>(args)...);
+}
+
+} // namespace tls
+} // namespace tcp_in