cleanup(libsinsp): introduce param->as<std::string>(), add error for …

…unsupported types

Signed-off-by: Luca Guerra <luca@guerra.sh>

userspace/libsinsp/event.cpp

@@ -2150,7 +2150,7 @@ void sinsp_evt::save_enter_event_params(sinsp_evt* enter_evt)
 		param = enter_evt->get_param_by_name(pname);
 		if(param)
 		{
-			std::string val {param->as<std::string_view>()};
+			std::string val = param->as<std::string>();
 			m_enter_path_param[pname] = val;
 		}
 	}

userspace/libsinsp/event.h

@@ -94,8 +94,10 @@ class SINSP_PUBLIC sinsp_evt_param
 	/*!
 	  \brief Interpret the parameter as a specific type, like:
 	  	- Fixed size values (uint32_t, int8_t ..., e.g. param->as<uint32_t>())
-		- String-like types (NUL-terminated strings) with std::string_view (e.g. param->as<std::string_view>())
-		  that can be used to instantiate an std::string and can also be accessed with .data() to get a pointer to a NUL-terminated string
+		- String-like types (NUL-terminated strings) with either:
+		  - std::string_view (e.g. param->as<std::string_view>()) to access the original string bytes or a NULL string
+		  - std::string (e.g. param->as<std::string>()) to obtain a copy of the string or an empty string if the parameter was NULL
+		- NUL-separated arrays of strings (e.g. "first\0second\0third\0") with std::vector<std::string>
 	*/
 	template<class T>
 	inline T as() const
@@ -119,6 +121,9 @@ class SINSP_PUBLIC sinsp_evt_param
 template<class T>
 inline T get_event_param_as(const sinsp_evt_param& param)
 {
+	static_assert(std::is_fundamental_v<T>,
+		"event parameter cast (e.g. evt->get_param(N)->as<T>()) unsupported for this type. Implement it or see the available definitions in " __FILE__);
+
 	T ret;
 
 	if (param.m_len != sizeof(T))
@@ -153,6 +158,26 @@ inline std::string_view get_event_param_as<std::string_view>(const sinsp_evt_par
 	return {param.m_val, string_len};
 }
 
+template<>
+inline std::string get_event_param_as<std::string>(const sinsp_evt_param& param)
+{
+	if (param.m_len == 0)
+	{
+		return "";
+	}
+
+	size_t string_len = strnlen(param.m_val, param.m_len);
+	// We expect the parameter to be exactly one null-terminated string
+	if (param.m_len != string_len + 1)
+	{
+		// By moving this error string building operation to a separate function
+		// the compiler is more likely to inline this entire function.
+		param.throw_invalid_len_error(string_len + 1);
+	}
+
+	return std::string(param.m_val);
+}
+
 template<>
 inline std::vector<std::string> get_event_param_as<std::vector<std::string>>(const sinsp_evt_param& param)
 {

userspace/libsinsp/parsers.cpp

@@ -1227,7 +1227,7 @@ void sinsp_parser::parse_clone_exit_caller(sinsp_evt *evt, int64_t child_tid)
 	child_tinfo->m_vpid = child_tinfo->m_pid;
 
 	/* exe */
-	child_tinfo->m_exe = evt->get_param(1)->as<std::string_view>();
+	child_tinfo->m_exe = evt->get_param(1)->as<std::string>();
 
 	/* args */
 	child_tinfo->set_args(evt->get_param(2)->as<std::vector<std::string>>());
@@ -1248,7 +1248,7 @@ void sinsp_parser::parse_clone_exit_caller(sinsp_evt *evt, int64_t child_tid)
 	case PPME_SYSCALL_VFORK_17_X:
 	case PPME_SYSCALL_VFORK_20_X:
 	case PPME_SYSCALL_CLONE3_X:
-		child_tinfo->m_comm = evt->get_param(13)->as<std::string_view>();
+		child_tinfo->m_comm = evt->get_param(13)->as<std::string>();
 		break;
 	default:
 		ASSERT(false);
@@ -1660,7 +1660,7 @@ void sinsp_parser::parse_clone_exit_child(sinsp_evt *evt)
 	 */
 
 	/* exe */
-	child_tinfo->m_exe = evt->get_param(1)->as<std::string_view>();
+	child_tinfo->m_exe = evt->get_param(1)->as<std::string>();
 
 	/* comm */
 	switch(etype)
@@ -1678,7 +1678,7 @@ void sinsp_parser::parse_clone_exit_child(sinsp_evt *evt)
 	case PPME_SYSCALL_VFORK_17_X:
 	case PPME_SYSCALL_VFORK_20_X:
 	case PPME_SYSCALL_CLONE3_X:
-		child_tinfo->m_comm = evt->get_param(13)->as<std::string_view>();
+		child_tinfo->m_comm = evt->get_param(13)->as<std::string>();
 		break;
 	default:
 		ASSERT(false);
@@ -2067,7 +2067,7 @@ void sinsp_parser::parse_execve_exit(sinsp_evt *evt)
 	case PPME_SYSCALL_EXECVE_19_X:
 	case PPME_SYSCALL_EXECVEAT_X:
 		// Get the comm
-		evt->get_tinfo()->m_comm = evt->get_param(13)->as<std::string_view>();
+		evt->get_tinfo()->m_comm = evt->get_param(13)->as<std::string>();
 		break;
 	default:
 		ASSERT(false);
@@ -4446,7 +4446,7 @@ void sinsp_parser::parse_getcwd_exit(sinsp_evt *evt)
 			return;
 		}
 
-		std::string cwd = std::string(evt->get_param(1)->as<std::string_view>());
+		std::string cwd = evt->get_param(1)->as<std::string>();
 
 #ifdef _DEBUG
 		if(cwd != "/")

userspace/libsinsp/sinsp_filtercheck_event.cpp

@@ -457,7 +457,7 @@ uint8_t *sinsp_filter_check_event::extract_abspath(sinsp_evt *evt, uint32_t *len
 			// Get the file path directly from the ring buffer.
 			// concatenate_paths takes care of resolving the path
 			//
-			m_strstorage = sinsp_utils::concatenate_paths("", evt->get_param(3)->as<std::string_view>());
+			m_strstorage = sinsp_utils::concatenate_paths("", evt->get_param(3)->as<std::string>());
 
 			RETURN_EXTRACT_STRING(m_strstorage);
 		}
@@ -1708,7 +1708,7 @@ uint8_t* sinsp_filter_check_event::extract_single(sinsp_evt *evt, uint32_t* len,
 
 			if(etype == PPME_INFRASTRUCTURE_EVENT_E)
 			{
-				std::string descstr{evt->get_param(2)->as<std::string_view>()};
+				std::string descstr{evt->get_param(2)->as<std::string>()};
 				vector<string> elements = sinsp_split(descstr, ';');
 				for(string ute : elements)
 				{

userspace/libsinsp/sinsp_filtercheck_fd.cpp

@@ -258,7 +258,7 @@ bool sinsp_filter_check_fd::extract_fdname_from_creator(sinsp_evt *evt, uint32_t
 		}
 	case PPME_SYSCALL_OPEN_BY_HANDLE_AT_X:
 		{
-			m_tstr = evt->get_param(3)->as<std::string_view>();
+			m_tstr = evt->get_param(3)->as<std::string>();
 
 			if(sanitize_strings)
 			{

userspace/libsinsp/test/events_param.ut.cpp

@@ -43,15 +43,15 @@ TEST_F(sinsp_with_test_input, charbuf_empty_param)
 
 	// this, and the following similar checks, verify that the internal state is set as we need right now.
 	// if the internal state changes we can remove or update this check
-	ASSERT_STREQ(evt->get_param(1)->as<std::string_view>().data(), "<NA>");
+	ASSERT_EQ(evt->get_param(1)->as<std::string>(), "<NA>");
 
 	/* `PPME_SYSCALL_CREAT_E` is a simple event that uses a `PT_FSPATH`
 	 * A `NULL` `PT_FSPATH` param is always converted to `<NA>`.
 	 */
 	evt = add_event_advance_ts(increasing_ts(), 1, PPME_SYSCALL_CREAT_E, 2, NULL, 0);
 	ASSERT_EQ(get_field_as_string(evt, "evt.arg.name"), "<NA>");
 
-	ASSERT_STREQ(evt->get_param(0)->as<std::string_view>().data(), "<NA>");
+	ASSERT_EQ(evt->get_param(0)->as<std::string>(), "<NA>");
 
 	int64_t dirfd = 0;
 
@@ -61,7 +61,7 @@ TEST_F(sinsp_with_test_input, charbuf_empty_param)
 	evt = add_event_advance_ts(increasing_ts(), 1, PPME_SYSCALL_EXECVEAT_E, 3, dirfd, NULL, 0);
 	ASSERT_EQ(get_field_as_string(evt, "evt.arg.pathname"), "<NA>");
 
-	ASSERT_STREQ(evt->get_param(1)->as<std::string_view>().data(), "<NA>");
+	ASSERT_EQ(evt->get_param(1)->as<std::string>(), "<NA>");
 }
 
 /* Assert that a `PT_CHARBUF` with `len==1` (just the `\0`) is not changed. */
@@ -81,7 +81,7 @@ TEST_F(sinsp_with_test_input, param_charbuf_len_1)
 	evt = add_event_advance_ts(increasing_ts(), 1, PPME_SYSCALL_CHDIR_X, 2, test_errno, "");
 	ASSERT_EQ(get_field_as_string(evt, "evt.arg.path"), "");
 
-	ASSERT_STREQ(evt->get_param(1)->as<std::string_view>().data(), "");
+	ASSERT_EQ(evt->get_param(1)->as<std::string>(), "");
 }
 
 /* Assert that a "(NULL)" `PT_CHARBUF` param is converted to `<NA>`
@@ -101,7 +101,7 @@ TEST_F(sinsp_with_test_input, charbuf_NULL_param)
 	evt = add_event_advance_ts(increasing_ts(), 1, PPME_SYSCALL_CHDIR_X, 2, test_errno, "(NULL)");
 	ASSERT_EQ(get_field_as_string(evt, "evt.arg.path"), "<NA>");
 
-	ASSERT_STREQ(evt->get_param(1)->as<std::string_view>().data(), "<NA>");
+	ASSERT_EQ(evt->get_param(1)->as<std::string>(), "<NA>");
 }
 
 /* Assert that an empty `PT_BYTEBUF` param is NOT converted to `<NA>` */