Added support for LM Sensors.

This uses `libsensors` as a source of temperature values, avoiding many issues with the current hwmon driver class.

CMakeLists.txt

@@ -20,6 +20,9 @@ endif()
 
 pkg_check_modules(ATASMART "libatasmart")
 
+find_library(LM_SENSORS_LIB NAMES "libsensors.so" "libsensors.so.5")
+find_path(LM_SENSORS_INC NAMES "sensors/sensors.h")
+
 if(SYSTEMD_FOUND)
 	set(PID_FILE "/run/thinkfan.pid")
 else()
@@ -39,6 +42,11 @@ option(USE_ATASMART "Enable reading temperatures from HDDs via S.M.A.R.T" OFF)
 #
 option(USE_NVML "Get temperatures directly from nVidia GPUs via their proprietary NVML API" ON)
 
+#
+# Defaults to ON.
+#
+option(USE_LM_SENSORS "Get temperatures from LM sensors" ON)
+
 #
 # The shiny new YAML config parser. Depends on yaml-cpp.
 #
@@ -100,6 +108,18 @@ if(USE_NVML)
 	target_link_libraries(thinkfan PRIVATE dl)
 endif(USE_NVML)
 
+if(USE_LM_SENSORS)
+	if(LM_SENSORS_LIB MATCHES "LM_SENSORS_LIB-NOTFOUND")
+		message(FATAL_ERROR "USE_LM_SENSORS enabled but libsensors not found. Please install libsensors-dev!")
+	elseif(LM_SENSORS_INC MATCHES "LM_SENSORS_INC-NOTFOUND")
+		message(FATAL_ERROR "USE_LM_SENSORS enabled but sensors/sensors.h not found. Please install libsensors-dev!")
+	else()
+		target_compile_definitions(thinkfan PRIVATE -DUSE_LM_SENSORS)
+		target_include_directories(thinkfan PRIVATE ${LM_SENSORS_INC})
+		target_link_libraries(thinkfan PRIVATE ${LM_SENSORS_LIB})
+	endif()
+endif(USE_LM_SENSORS)
+
 if(USE_YAML)
 	target_compile_definitions(thinkfan PRIVATE -DUSE_YAML)
 	target_include_directories(thinkfan PRIVATE ${YAML_CPP_INCLUDE_DIRS})

README.md

@@ -53,6 +53,11 @@ To compile thinkfan, you will need to have the following things installed:
        this only when you really need it, since libatasmart is unreasonably
        CPU-intensive.
 
+   `USE_LM_SENSORS:BOOL` (default: `ON`)
+       Use LM sensors to read temperatures directly from Linux drivers.
+       The `libsensors` library needs to be installed for this feature, probably
+       with required headers and development files (e.g., `libsensors-dev`).
+
    `USE_YAML:BOOL` (default: `ON`)
        Support config file in the new, more flexible YAML format. The old
        config format will be deprecated after the thinkfan 1.0 release. New

examples/thinkfan.yaml

@@ -28,6 +28,34 @@
 # sensor.
 
 sensors:
+  # LM Sensors
+  # ==========
+  # Temperatures can be read directly from Linux drivers through the LM sensors.
+  #
+  # To configure this, install "lm-sensors" and "libsensors", then
+  # run "sensors-detect", then run "sensors".
+  # To build thinkfan from sources, you'll also need to install "libsensors-dev"
+  # or equivalent package for your distribution.
+  #
+  # For example, the following output of "sensors":
+  # ...
+  # thinkpad-isa-0000
+  # Adapter: ISA adapter
+  # fan1:        2618 RPM
+  # fan2:        2553 RPM
+  # CPU:          +63.0 C  
+  # GPU 1:        +55.0 C  
+  # temp3:        +68.0 C  
+  # temp4:         +0.0 C  
+  # temp5:        +60.0 C  
+  # temp6:        +64.0 C  
+  # temp7:        +67.0 C  
+  # temp8:         +0.0 C  
+  # ...
+  # would result in the following configuration:
+  - chip: thinkpad-isa-0000
+    ids: [ CPU, "GPU 1", temp3, temp4, temp5, temp6, temp7, temp8 ]
+
   # hwmon: Full path to a temperature file (single sensor).
   # =======================================================
   # Disadvantage is that the index in "hwmon0" depends on the load order of

src/sensors.cpp

@@ -341,4 +341,187 @@ void NvmlSensorDriver::read_temps_(TemperatureState &global_temps) const
 #endif /* USE_NVML */
 
 
+#ifdef USE_LM_SENSORS
+
+/*----------------------------------------------------------------------------
+| LMSensorsDriver: Driver for sensors provided by LM sensors's `libsensors`. |
+----------------------------------------------------------------------------*/
+
+// Closest integer value to zero Kelvin.
+static const int MIN_CELSIUS_TEMP = -273;
+
+std::once_flag LMSensorsDriver::lm_sensors_once_init_;
+
+LMSensorsDriver::LMSensorsDriver(
+	string chip_name, std::vector<string> feature_names,
+ 	bool optional, std::vector<int> correction)
+	: SensorDriver(optional),
+	  chip_name_(chip_name), chip_(nullptr), feature_names_(feature_names)
+{
+	LMSensorsDriver::ensure_lm_sensors_is_initialized();
+	chip_ = LMSensorsDriver::find_chip_by_name(chip_name_);
+	path_ = chip_->path;
+
+	size_t len = feature_names_.size();
+	for (size_t i = 0; i < len; ++i) {
+		const string& feature_name = feature_names_[i];
+
+		auto feature = LMSensorsDriver::find_feature_by_name(
+			*chip_, chip_name_, feature_name);
+		if (!feature) {
+			throw SystemError("LM sensors chip '" + chip_name
+				+ "' does not have the feature '" + feature_name + "'");
+		}
+		features_.push_back(feature);
+
+		auto sub_feature = ::sensors_get_subfeature(
+			chip_, feature, ::SENSORS_SUBFEATURE_TEMP_INPUT);
+		if (!sub_feature) {
+			throw SystemError("LM sensors feature '" + feature_name
+				+ "' of the chip '" + chip_name_
+				+ "' does not have a temperature input sensor");
+		}
+		sub_features_.push_back(sub_feature);
+
+		log(TF_DBG) << "Initialized LM sensors temperature input of feature '"
+			+ feature_name + "' of chip '" + chip_name_ + "'." << flush;
+	}
+
+	if (correction.empty()) {
+		correction.resize(feature_names_.size(), 0);
+	}
+
+	set_num_temps(feature_names_.size());
+	set_correction(correction);
+}
+
+LMSensorsDriver::~LMSensorsDriver() noexcept(false) {}
+
+void LMSensorsDriver::ensure_lm_sensors_is_initialized() {
+	int r = 0;
+	std::call_once(LMSensorsDriver::lm_sensors_once_init_,
+				   LMSensorsDriver::initialize_lm_sensors, &r);
+	if (r != 0) {
+		const char *msg = ::sensors_strerror(r);
+		throw SystemError(string("Failed to initialize LM sensors driver: ") + msg);
+	}
+}
+
+void LMSensorsDriver::initialize_lm_sensors(int* result) {
+	::sensors_parse_error = LMSensorsDriver::parse_error_call_back;
+	::sensors_parse_error_wfn = LMSensorsDriver::parse_error_wfn_call_back;
+	::sensors_fatal_error = LMSensorsDriver::fatal_error_call_back;
+
+	if ((*result = ::sensors_init(nullptr)) == 0) {
+		atexit(::sensors_cleanup);
+	}
+
+	log(TF_DBG) << "Initialized LM sensors." << flush;
+}
+
+const ::sensors_chip_name* LMSensorsDriver::find_chip_by_name(
+	const string& chip_name)
+{
+	int state = 0;
+	for (;;) {
+		auto chip = ::sensors_get_detected_chips(nullptr, &state);
+		if (!chip) break;
+
+		if (chip_name == LMSensorsDriver::get_chip_name(*chip)) return chip;
+	}
+
+	throw SystemError("LM sensors chip '" + chip_name + "' was not found");
+}
+
+string LMSensorsDriver::get_chip_name(const ::sensors_chip_name& chip) {
+	int len = sensors_snprintf_chip_name(nullptr, 0, &chip);
+	if (len < 0) {
+		const char *msg = ::sensors_strerror(len);
+		throw SystemError(string("Failed to get LM sensors chip name: ") + msg);
+	}
+
+	std::vector<char> buffer((size_t)(len + 1));
+	int r = sensors_snprintf_chip_name(buffer.data(), (size_t)(len + 1), &chip);
+	if (r < 0) {
+		const char *msg = ::sensors_strerror(r);
+		throw SystemError(string("Failed to get LM sensors chip name: ") + msg);
+	} else if (r >= (len + 1)) {
+		throw SystemError("LM sensors chip name is too long");
+	}
+	return string(buffer.data(), r);
+}
+
+const ::sensors_feature* LMSensorsDriver::find_feature_by_name(
+	const ::sensors_chip_name& chip, const string& chip_name,
+	const string& feature_name)
+{
+	int state = 0;
+	for (;;) {
+		auto feature = ::sensors_get_features(&chip, &state);
+		if (!feature) break;
+
+		auto label = ::sensors_get_label(&chip, feature);
+		bool label_matches = (feature_name == label);
+		free(label);
+
+		if (label_matches) return feature;
+	}
+	return nullptr;
+}
+
+void LMSensorsDriver::parse_error_call_back(const char *err, int line_no) {
+	log(TF_ERR) << "LM sensors parsing error: " << err << " in line "
+		<< std::to_string(line_no);
+}
+
+void LMSensorsDriver::parse_error_wfn_call_back(
+	const char *err, const char *file_name, int line_no)
+{
+	log(TF_ERR) << "LM sensors parsing error: " << err << " in file '"
+		<< file_name << "' at line " << std::to_string(line_no);
+}
+
+void LMSensorsDriver::fatal_error_call_back(const char *proc, const char *err) {
+	log(TF_ERR) << "LM sensors fatal error in " << proc << ": " << err;
+	exit(EXIT_FAILURE);
+}
+
+void LMSensorsDriver::read_temps_(TemperatureState &global_temps) const {
+	size_t len = sub_features_.size();
+	for (size_t i = 0; i < len; ++i) {
+		auto sub_feature = sub_features_[i];
+
+		double real_value = MIN_CELSIUS_TEMP;
+		int r = ::sensors_get_value(chip_, sub_feature->number, &real_value);
+
+		int integer_value;
+		if (r == 0) {
+			integer_value = int(real_value) + correction_[i];
+		} else {
+			// NOTICE:
+			// If this happens, then all remaining temperature sources reported
+			// by the current driver instance are skipped.
+			//
+			// Sources of temperatures that are not always available should be
+			// configured on their own "- chip" entry, and marked optional.
+			integer_value = MIN_CELSIUS_TEMP;
+
+			const char *msg = ::sensors_strerror(r);
+			throw SystemError(
+				string("temperature input value of feature '")
+				+ feature_names_[i] + "' of chip '" + chip_name_
+				+ "' is unavailable: " + msg);
+		}
+
+		if (integer_value < MIN_CELSIUS_TEMP) {
+			// Make sure the reported value is physically valid.
+			integer_value = MIN_CELSIUS_TEMP;
+		}
+
+		global_temps.add_temp(integer_value);
+	}
+}
+
+#endif /* USE_LM_SENSORS */
+
 }

src/sensors.h

@@ -32,6 +32,13 @@
 #include <nvidia/gdk/nvml.h>
 #endif /* USE_NVML */
 
+#ifdef USE_LM_SENSORS
+#include <sensors/sensors.h>
+#include <sensors/error.h>
+#include <atomic>
+#include <mutex>
+#endif /* USE_LM_SENSORS */
+
 namespace thinkfan {
 
 class ExpectedError;
@@ -141,5 +148,44 @@ class NvmlSensorDriver : public SensorDriver {
 #endif /* USE_NVML */
 
 
+#ifdef USE_LM_SENSORS
+
+class LMSensorsDriver : public SensorDriver {
+public:
+	LMSensorsDriver(string chip_name, std::vector<string> feature_names,
+	                bool optional, std::vector<int> correction = {});
+	virtual ~LMSensorsDriver();
+
+protected:
+	virtual void read_temps_(TemperatureState &global_temps) const override;
+
+	// LM sensors helpers.
+	static void ensure_lm_sensors_is_initialized();
+	static void initialize_lm_sensors(int* result);
+	static const ::sensors_chip_name* find_chip_by_name(
+		const string& chip_name);
+	static const ::sensors_feature* find_feature_by_name(
+		const ::sensors_chip_name& chip, const string& chip_name,
+		const string& feature_name);
+	static string get_chip_name(const ::sensors_chip_name& chip);
+
+	// LM sensors call backs.
+	static void parse_error_call_back(const char *err, int line_no);
+	static void parse_error_wfn_call_back(const char *err, const char *file_name, int line_no);
+	static void fatal_error_call_back(const char *proc, const char *err);
+
+private:
+	const string chip_name_;
+	const ::sensors_chip_name* chip_;
+
+	const std::vector<string> feature_names_;
+	std::vector<const ::sensors_feature*> features_;
+	std::vector<const ::sensors_subfeature*> sub_features_;
+
+	static std::once_flag lm_sensors_once_init_;
+};
+
+#endif /* USE_LM_SENSORS */
+
 }