Added the ability to read some CPU and other temperature sensors.

board-sensors.c

@@ -0,0 +1,122 @@
+#include <dirent.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "board-sensors.h"
+
+int find_board_sensors(struct hwmon_avail_sensor *board_sensors, int max_sensors)
+{
+	const char *hwmon_path = "/sys/class/hwmon/";
+	char device_path[NAME_MAX];
+	char sensor_path[NAME_MAX];
+	
+	char driver_name[256];
+	
+	FILE *file;
+	DIR *dir;
+	struct dirent *ent;
+	
+	int num_sensors = 0;
+	
+	/* Start looking for hwmon devices in /sys/class/hwmon/ */
+	dir = opendir(hwmon_path);
+	
+	/* make sure we can open the device directory */
+	if(dir == NULL)
+		return 0;
+	
+	/* loop over all hwmon devices */
+	while((ent = readdir(dir)) != NULL)
+	{
+		/* Ignore any non-hwmon dirs */
+		if(strncmp(ent->d_name, "hwmon", 5) != 0) 
+			continue;
+		
+		strcpy(device_path, hwmon_path);
+		strcat(device_path, ent->d_name);
+		
+		/* Read in the name of the device */
+		strcpy(sensor_path, device_path);
+		strcat(sensor_path, "/name");
+		
+		file = fopen(sensor_path, "r");
+		if (file == NULL)
+			continue;
+		
+		if (fgets(driver_name, sizeof(driver_name), file) == NULL) {
+			fclose(file);
+			continue;
+		}
+		
+		fclose(file);
+
+		/* Driver names have a linebreak at the end so let's remove that for comparison*/
+		driver_name[strlen(driver_name) - 1] = '\0';
+		
+		/* Loop through all supported sensors and see if any are present in this device */
+		for (int i = 0; i < (sizeof(hwmon_sensor_info) / sizeof(struct hwmon_sensor)); i++) {
+			if (strcmp(driver_name, hwmon_sensor_info[i].driver_name) == 0) {
+				/* We matched the driver name, try to open the files */
+				strcpy(sensor_path, device_path);
+				strcat(sensor_path, "/");
+				strcat(sensor_path, hwmon_sensor_info[i].sensor_file_name);
+				strcat(sensor_path, "_input");
+				
+				file = fopen(sensor_path, "r");
+				if (file != NULL) {
+					fclose(file);
+					/* Good open of the sensor file */
+					board_sensors[num_sensors].file = calloc(NAME_MAX, sizeof(char));
+					strcpy(board_sensors[num_sensors].file, sensor_path);
+					board_sensors[num_sensors].sort_index = i;
+					board_sensors[num_sensors].sensor_info = &hwmon_sensor_info[i];
+					
+					/* Read in the sensor name */
+					board_sensors[num_sensors].sensor_name = calloc(MAX_SENSOR_NAME_LENGTH, sizeof(char));
+					strcpy(sensor_path, device_path);
+					strcat(sensor_path, "/");
+					strcat(sensor_path, hwmon_sensor_info[i].sensor_file_name);
+					strcat(sensor_path, "_label");
+					
+					file = fopen(sensor_path, "r");
+					if (file != NULL)
+						fgets(board_sensors[num_sensors].sensor_name, MAX_SENSOR_NAME_LENGTH, file);
+
+					/* Sensor name seems to always have a trailing newline we don't want */
+					size_t len_without_newline = strcspn(board_sensors[num_sensors].sensor_name, "\n");
+					board_sensors[num_sensors].sensor_name[len_without_newline] = '\0';
+					
+					if (num_sensors == max_sensors)
+						return num_sensors;
+					num_sensors++;
+				}
+			}
+		}
+		
+	}
+	
+	return num_sensors;
+}
+
+/* Returns 0 on a bad read or missing sensor, 1 on OK */
+int get_sensor_reading(struct hwmon_avail_sensor *sensor, float *reading) {
+	char buf[256] = {0};
+	long int raw;
+	FILE *file;
+	
+	file = fopen(sensor->file, "r");
+	if (file == NULL)
+		return 0;
+
+	fgets(buf, 256, file);
+	raw = strtol(buf, NULL, 10);
+	
+	fclose(file);
+	
+	*reading = (float)raw / sensor->sensor_info->divisor;
+
+	if (*reading == sensor->sensor_info->bad_value)
+		return 0;
+	
+	return 1;
+}