freeipmiUtil: implement IPMI reading using ipmi-sensors from FreeIPMI project (#220)

Also add an option tu use sudo non-interactively.

freon@UshakovVasilii_Github.yahoo.com/freeipmiUtil.js

@@ -0,0 +1,100 @@
+const GLib = imports.gi.GLib;
+
+const Me = imports.misc.extensionUtils.getCurrentExtension();
+const CommandLineUtil = Me.imports.commandLineUtil;
+
+var FreeipmiUtil = class extends CommandLineUtil.CommandLineUtil {
+    constructor() {
+        super();
+
+        const path = GLib.find_program_in_path('ipmi-sensors');
+        // --comma-separated-output: pseudo csv output format, splitting on comma may be good enough for the values we read.
+        this._argv = path ? [path, '--comma-separated-output'] : null;
+
+        if (this._argv) {
+            const ExtensionUtils = imports.misc.extensionUtils;
+            const Me = ExtensionUtils.getCurrentExtension();
+            if (ExtensionUtils.getSettings().get_string('method-ipmi-utility') === 'sudo')
+            {
+                const sudo_path = GLib.find_program_in_path('sudo');
+                // --non-interactive: do not ask for password, return if no permission.
+                this._argv = sudo_path ? [sudo_path, '--non-interactive'].concat(this._argv) : null;
+            }
+        }
+    }
+
+    // Avoid parsing the data more than once.
+    execute(callback) {
+        super.execute(() => {
+            let data = [];
+
+            for (const line of this._output) {
+                if (!line)
+                    continue;
+
+                const value_list = line.split(',');
+
+                if (value_list.length <= 1)
+                    break;
+
+                const id = value_list[0];
+
+                if (id === 'ID')
+                    continue;
+
+                const name = value_list[1];
+                const value = value_list[3];
+                const unit = value_list[4];
+
+                if (value !== 'N/A' && unit !== 'N/A') {
+                    data[name] = {};
+                    data[name]["value"] = value;
+                    data[name]["unit"] = unit;
+                }
+            }
+
+            this._data = data;
+            callback();
+        });
+    }
+
+    get temp() {
+        return this._parseSensorsOutput(/^(C|C per minute)$/, 'temp');
+    }
+
+    get rpm() {
+        return this._parseSensorsOutput(/^RPM$/, 'rpm');
+    }
+
+    get volt() {
+        return this._parseSensorsOutput(/^V$/, 'volt');
+    }
+
+  _parseSensorsOutput(sensorFilter, sensorType) {
+        if(!this._data)
+            return [];
+
+        const data = this._data;
+
+        let sensors = [];
+        for (const name in data) {
+            if (!data.hasOwnProperty(name))
+                continue;
+
+            const value = data[name]["value"]
+            const unit = data[name]["unit"]
+
+            if (!sensorFilter.test(unit))
+                continue;
+
+            const feature = {
+                label: name,
+                [sensorType]: parseFloat(value)
+            };
+
+            sensors.push(feature);
+        }
+
+        return sensors;
+    }
+};