1 /*
2 // Copyright (c) 2017 Intel Corporation
3 //
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 //
8 //      http://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
11 // distributed under the License is distributed on an "AS IS" BASIS,
12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 // See the License for the specific language governing permissions and
14 // limitations under the License.
15 */
16 
17 #include "DeviceMgmt.hpp"
18 #include "HwmonTempSensor.hpp"
19 #include "SensorPaths.hpp"
20 #include "Thresholds.hpp"
21 #include "Utils.hpp"
22 
23 #include <boost/asio/error.hpp>
24 #include <boost/asio/io_context.hpp>
25 #include <boost/asio/post.hpp>
26 #include <boost/asio/steady_timer.hpp>
27 #include <boost/container/flat_map.hpp>
28 #include <boost/container/flat_set.hpp>
29 #include <sdbusplus/asio/connection.hpp>
30 #include <sdbusplus/asio/object_server.hpp>
31 #include <sdbusplus/bus.hpp>
32 #include <sdbusplus/bus/match.hpp>
33 #include <sdbusplus/message.hpp>
34 #include <sdbusplus/message/native_types.hpp>
35 
36 #include <algorithm>
37 #include <array>
38 #include <chrono>
39 #include <cstddef>
40 #include <cstdint>
41 #include <filesystem>
42 #include <functional>
43 #include <ios>
44 #include <iostream>
45 #include <memory>
46 #include <optional>
47 #include <regex>
48 #include <string>
49 #include <system_error>
50 #include <utility>
51 #include <variant>
52 #include <vector>
53 
54 static constexpr float pollRateDefault = 0.5;
55 
56 static constexpr double maxValuePressure = 120000;      // Pascals
57 static constexpr double minValuePressure = 30000;       // Pascals
58 
59 static constexpr double maxValueRelativeHumidity = 100; // PercentRH
60 static constexpr double minValueRelativeHumidity = 0;   // PercentRH
61 
62 static constexpr double maxValueTemperature = 127;      // DegreesC
63 static constexpr double minValueTemperature = -128;     // DegreesC
64 
65 namespace fs = std::filesystem;
66 
67 static const I2CDeviceTypeMap sensorTypes{
68     {"ADM1021", I2CDeviceType{"adm1021", true}},
69     {"DPS310", I2CDeviceType{"dps310", false}},
70     {"EMC1403", I2CDeviceType{"emc1403", true}},
71     {"EMC1412", I2CDeviceType{"emc1412", true}},
72     {"EMC1413", I2CDeviceType{"emc1413", true}},
73     {"EMC1414", I2CDeviceType{"emc1414", true}},
74     {"HDC1080", I2CDeviceType{"hdc1080", false}},
75     {"JC42", I2CDeviceType{"jc42", true}},
76     {"LM75A", I2CDeviceType{"lm75a", true}},
77     {"LM95234", I2CDeviceType{"lm95234", true}},
78     {"MAX31725", I2CDeviceType{"max31725", true}},
79     {"MAX31730", I2CDeviceType{"max31730", true}},
80     {"MAX6581", I2CDeviceType{"max6581", true}},
81     {"MAX6654", I2CDeviceType{"max6654", true}},
82     {"MAX6639", I2CDeviceType{"max6639", true}},
83     {"MCP9600", I2CDeviceType{"mcp9600", false}},
84     {"NCT6779", I2CDeviceType{"nct6779", true}},
85     {"NCT7802", I2CDeviceType{"nct7802", true}},
86     {"PT5161L", I2CDeviceType{"pt5161l", true}},
87     {"SBTSI", I2CDeviceType{"sbtsi", true}},
88     {"SI7020", I2CDeviceType{"si7020", false}},
89     {"TMP100", I2CDeviceType{"tmp100", true}},
90     {"TMP112", I2CDeviceType{"tmp112", true}},
91     {"TMP175", I2CDeviceType{"tmp175", true}},
92     {"TMP421", I2CDeviceType{"tmp421", true}},
93     {"TMP441", I2CDeviceType{"tmp441", true}},
94     {"TMP461", I2CDeviceType{"tmp461", true}},
95     {"TMP464", I2CDeviceType{"tmp464", true}},
96     {"TMP75", I2CDeviceType{"tmp75", true}},
97     {"W83773G", I2CDeviceType{"w83773g", true}},
98 };
99 
100 static struct SensorParams
getSensorParameters(const std::filesystem::path & path)101     getSensorParameters(const std::filesystem::path& path)
102 {
103     // offset is to default to 0 and scale to 1, see lore
104     // https://lore.kernel.org/linux-iio/5c79425f-6e88-36b6-cdfe-4080738d039f@metafoo.de/
105     struct SensorParams tmpSensorParameters = {
106         .minValue = minValueTemperature,
107         .maxValue = maxValueTemperature,
108         .offsetValue = 0.0,
109         .scaleValue = 1.0,
110         .units = sensor_paths::unitDegreesC,
111         .typeName = "temperature"};
112 
113     // For IIO RAW sensors we get a raw_value, an offset, and scale
114     // to compute the value = (raw_value + offset) * scale
115     // with a _raw IIO device we need to get the
116     // offsetValue and scaleValue from the driver
117     // these are used to compute the reading in
118     // units that have yet to be scaled for D-Bus.
119     const std::string pathStr = path.string();
120     if (pathStr.ends_with("_raw"))
121     {
122         std::string pathOffsetStr = pathStr.substr(0, pathStr.size() - 4) +
123                                     "_offset";
124         std::optional<double> tmpOffsetValue = readFile(pathOffsetStr, 1.0);
125         // In case there is nothing to read skip this device
126         // This is not an error condition see lore
127         // https://lore.kernel.org/linux-iio/5c79425f-6e88-36b6-cdfe-4080738d039f@metafoo.de/
128         if (tmpOffsetValue)
129         {
130             tmpSensorParameters.offsetValue = *tmpOffsetValue;
131         }
132 
133         std::string pathScaleStr = pathStr.substr(0, pathStr.size() - 4) +
134                                    "_scale";
135         std::optional<double> tmpScaleValue = readFile(pathScaleStr, 1.0);
136         // In case there is nothing to read skip this device
137         // This is not an error condition see lore
138         // https://lore.kernel.org/linux-iio/5c79425f-6e88-36b6-cdfe-4080738d039f@metafoo.de/
139         if (tmpScaleValue)
140         {
141             tmpSensorParameters.scaleValue = *tmpScaleValue;
142         }
143     }
144 
145     // Temperatures are read in milli degrees Celsius, we need
146     // degrees Celsius. Pressures are read in kilopascal, we need
147     // Pascals.  On D-Bus for Open BMC we use the International
148     // System of Units without prefixes. Links to the kernel
149     // documentation:
150     // https://www.kernel.org/doc/Documentation/hwmon/sysfs-interface
151     // https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-bus-iio
152     if (path.filename() == "in_pressure_input" ||
153         path.filename() == "in_pressure_raw")
154     {
155         tmpSensorParameters.minValue = minValuePressure;
156         tmpSensorParameters.maxValue = maxValuePressure;
157         // Pressures are read in kilopascal, we need Pascals.
158         tmpSensorParameters.scaleValue *= 1000.0;
159         tmpSensorParameters.typeName = "pressure";
160         tmpSensorParameters.units = sensor_paths::unitPascals;
161     }
162     else if (path.filename() == "in_humidityrelative_input" ||
163              path.filename() == "in_humidityrelative_raw")
164     {
165         tmpSensorParameters.minValue = minValueRelativeHumidity;
166         tmpSensorParameters.maxValue = maxValueRelativeHumidity;
167         // Relative Humidity are read in milli-percent, we need percent.
168         tmpSensorParameters.scaleValue *= 0.001;
169         tmpSensorParameters.typeName = "humidity";
170         tmpSensorParameters.units = sensor_paths::unitPercentRH;
171     }
172     else
173     {
174         // Temperatures are read in milli degrees Celsius,
175         // we need degrees Celsius.
176         tmpSensorParameters.scaleValue *= 0.001;
177     }
178 
179     return tmpSensorParameters;
180 }
181 
182 struct SensorConfigKey
183 {
184     uint64_t bus;
185     uint64_t addr;
operator <SensorConfigKey186     bool operator<(const SensorConfigKey& other) const
187     {
188         if (bus != other.bus)
189         {
190             return bus < other.bus;
191         }
192         return addr < other.addr;
193     }
194 };
195 
196 struct SensorConfig
197 {
198     std::string sensorPath;
199     SensorData sensorData;
200     std::string interface;
201     SensorBaseConfigMap config;
202     std::vector<std::string> name;
203 };
204 
205 using SensorConfigMap =
206     boost::container::flat_map<SensorConfigKey, SensorConfig>;
207 
208 static SensorConfigMap
buildSensorConfigMap(const ManagedObjectType & sensorConfigs)209     buildSensorConfigMap(const ManagedObjectType& sensorConfigs)
210 {
211     SensorConfigMap configMap;
212     for (const auto& [path, cfgData] : sensorConfigs)
213     {
214         for (const auto& [intf, cfg] : cfgData)
215         {
216             auto busCfg = cfg.find("Bus");
217             auto addrCfg = cfg.find("Address");
218             if ((busCfg == cfg.end()) || (addrCfg == cfg.end()))
219             {
220                 continue;
221             }
222 
223             if ((std::get_if<uint64_t>(&busCfg->second) == nullptr) ||
224                 (std::get_if<uint64_t>(&addrCfg->second) == nullptr))
225             {
226                 std::cerr << path.str << " Bus or Address invalid\n";
227                 continue;
228             }
229 
230             std::vector<std::string> hwmonNames;
231             auto nameCfg = cfg.find("Name");
232             if (nameCfg != cfg.end())
233             {
234                 hwmonNames.push_back(std::get<std::string>(nameCfg->second));
235                 size_t i = 1;
236                 while (true)
237                 {
238                     auto sensorNameCfg = cfg.find("Name" + std::to_string(i));
239                     if (sensorNameCfg == cfg.end())
240                     {
241                         break;
242                     }
243                     hwmonNames.push_back(
244                         std::get<std::string>(sensorNameCfg->second));
245                     i++;
246                 }
247             }
248 
249             SensorConfigKey key = {std::get<uint64_t>(busCfg->second),
250                                    std::get<uint64_t>(addrCfg->second)};
251             SensorConfig val = {path.str, cfgData, intf, cfg, hwmonNames};
252 
253             auto [it, inserted] = configMap.emplace(key, std::move(val));
254             if (!inserted)
255             {
256                 std::cerr << path.str << ": ignoring duplicate entry for {"
257                           << key.bus << ", 0x" << std::hex << key.addr
258                           << std::dec << "}\n";
259             }
260         }
261     }
262     return configMap;
263 }
264 
createSensors(boost::asio::io_context & io,sdbusplus::asio::object_server & objectServer,boost::container::flat_map<std::string,std::shared_ptr<HwmonTempSensor>> & sensors,std::shared_ptr<sdbusplus::asio::connection> & dbusConnection,const std::shared_ptr<boost::container::flat_set<std::string>> & sensorsChanged,bool activateOnly)265 void createSensors(
266     boost::asio::io_context& io, sdbusplus::asio::object_server& objectServer,
267     boost::container::flat_map<std::string, std::shared_ptr<HwmonTempSensor>>&
268         sensors,
269     std::shared_ptr<sdbusplus::asio::connection>& dbusConnection,
270     const std::shared_ptr<boost::container::flat_set<std::string>>&
271         sensorsChanged,
272     bool activateOnly)
273 {
274     auto getter = std::make_shared<GetSensorConfiguration>(
275         dbusConnection,
276         [&io, &objectServer, &sensors, &dbusConnection, sensorsChanged,
277          activateOnly](const ManagedObjectType& sensorConfigurations) {
278         bool firstScan = sensorsChanged == nullptr;
279 
280         SensorConfigMap configMap = buildSensorConfigMap(sensorConfigurations);
281 
282         auto devices = instantiateDevices(sensorConfigurations, sensors,
283                                           sensorTypes);
284 
285         // IIO _raw devices look like this on sysfs:
286         //     /sys/bus/iio/devices/iio:device0/in_temp_raw
287         //     /sys/bus/iio/devices/iio:device0/in_temp_offset
288         //     /sys/bus/iio/devices/iio:device0/in_temp_scale
289         //
290         // Other IIO devices look like this on sysfs:
291         //     /sys/bus/iio/devices/iio:device1/in_temp_input
292         //     /sys/bus/iio/devices/iio:device1/in_pressure_input
293         std::vector<fs::path> paths;
294         fs::path root("/sys/bus/iio/devices");
295         findFiles(root, R"(in_temp\d*_(input|raw))", paths);
296         findFiles(root, R"(in_pressure\d*_(input|raw))", paths);
297         findFiles(root, R"(in_humidityrelative\d*_(input|raw))", paths);
298         findFiles(fs::path("/sys/class/hwmon"), R"(temp\d+_input)", paths);
299 
300         // iterate through all found temp and pressure sensors,
301         // and try to match them with configuration
302         for (auto& path : paths)
303         {
304             std::smatch match;
305             const std::string pathStr = path.string();
306             auto directory = path.parent_path();
307             fs::path device;
308 
309             std::string deviceName;
310             std::error_code ec;
311             if (pathStr.starts_with("/sys/bus/iio/devices"))
312             {
313                 device = fs::canonical(directory, ec);
314                 if (ec)
315                 {
316                     std::cerr << "Fail to find device in path [" << pathStr
317                               << "]\n";
318                     continue;
319                 }
320                 deviceName = device.parent_path().stem();
321             }
322             else
323             {
324                 device = fs::canonical(directory / "device", ec);
325                 if (ec)
326                 {
327                     std::cerr << "Fail to find device in path [" << pathStr
328                               << "]\n";
329                     continue;
330                 }
331                 deviceName = device.stem();
332             }
333 
334             uint64_t bus = 0;
335             uint64_t addr = 0;
336             if (!getDeviceBusAddr(deviceName, bus, addr))
337             {
338                 continue;
339             }
340 
341             auto thisSensorParameters = getSensorParameters(path);
342             auto findSensorCfg = configMap.find({bus, addr});
343             if (findSensorCfg == configMap.end())
344             {
345                 continue;
346             }
347 
348             const std::string& interfacePath = findSensorCfg->second.sensorPath;
349             auto findI2CDev = devices.find(interfacePath);
350 
351             std::shared_ptr<I2CDevice> i2cDev;
352             if (findI2CDev != devices.end())
353             {
354                 // If we're only looking to activate newly-instantiated i2c
355                 // devices and this sensor's underlying device was already there
356                 // before this call, there's nothing more to do here.
357                 if (activateOnly && !findI2CDev->second.second)
358                 {
359                     continue;
360                 }
361                 i2cDev = findI2CDev->second.first;
362             }
363 
364             const SensorData& sensorData = findSensorCfg->second.sensorData;
365             std::string sensorType = findSensorCfg->second.interface;
366             auto pos = sensorType.find_last_of('.');
367             if (pos != std::string::npos)
368             {
369                 sensorType = sensorType.substr(pos + 1);
370             }
371             const SensorBaseConfigMap& baseConfigMap =
372                 findSensorCfg->second.config;
373             std::vector<std::string>& hwmonName = findSensorCfg->second.name;
374 
375             // Temperature has "Name", pressure has "Name1"
376             auto findSensorName = baseConfigMap.find("Name");
377             int index = 1;
378             if (thisSensorParameters.typeName == "pressure" ||
379                 thisSensorParameters.typeName == "humidity")
380             {
381                 findSensorName = baseConfigMap.find("Name1");
382                 index = 2;
383             }
384 
385             if (findSensorName == baseConfigMap.end())
386             {
387                 std::cerr << "could not determine configuration name for "
388                           << deviceName << "\n";
389                 continue;
390             }
391             std::string sensorName =
392                 std::get<std::string>(findSensorName->second);
393             // on rescans, only update sensors we were signaled by
394             auto findSensor = sensors.find(sensorName);
395             if (!firstScan && findSensor != sensors.end())
396             {
397                 bool found = false;
398                 auto it = sensorsChanged->begin();
399                 while (it != sensorsChanged->end())
400                 {
401                     if (it->ends_with(findSensor->second->name))
402                     {
403                         it = sensorsChanged->erase(it);
404                         findSensor->second = nullptr;
405                         found = true;
406                         break;
407                     }
408                     ++it;
409                 }
410                 if (!found)
411                 {
412                     continue;
413                 }
414             }
415 
416             std::vector<thresholds::Threshold> sensorThresholds;
417 
418             if (!parseThresholdsFromConfig(sensorData, sensorThresholds,
419                                            nullptr, &index))
420             {
421                 std::cerr << "error populating thresholds for " << sensorName
422                           << " index " << index << "\n";
423             }
424 
425             float pollRate = getPollRate(baseConfigMap, pollRateDefault);
426             PowerState readState = getPowerState(baseConfigMap);
427 
428             auto permitSet = getPermitSet(baseConfigMap);
429             auto& sensor = sensors[sensorName];
430             if (!activateOnly)
431             {
432                 sensor = nullptr;
433             }
434             auto hwmonFile = getFullHwmonFilePath(directory.string(), "temp1",
435                                                   permitSet);
436             if (pathStr.starts_with("/sys/bus/iio/devices"))
437             {
438                 hwmonFile = pathStr;
439             }
440             if (hwmonFile)
441             {
442                 if (sensor != nullptr)
443                 {
444                     sensor->activate(*hwmonFile, i2cDev);
445                 }
446                 else
447                 {
448                     sensor = std::make_shared<HwmonTempSensor>(
449                         *hwmonFile, sensorType, objectServer, dbusConnection,
450                         io, sensorName, std::move(sensorThresholds),
451                         thisSensorParameters, pollRate, interfacePath,
452                         readState, i2cDev);
453                     sensor->setupRead();
454                 }
455             }
456             hwmonName.erase(
457                 remove(hwmonName.begin(), hwmonName.end(), sensorName),
458                 hwmonName.end());
459 
460             // Looking for keys like "Name1" for temp2_input,
461             // "Name2" for temp3_input, etc.
462             int i = 0;
463             while (true)
464             {
465                 ++i;
466                 auto findKey = baseConfigMap.find("Name" + std::to_string(i));
467                 if (findKey == baseConfigMap.end())
468                 {
469                     break;
470                 }
471                 std::string sensorName = std::get<std::string>(findKey->second);
472                 hwmonFile = getFullHwmonFilePath(directory.string(),
473                                                  "temp" + std::to_string(i + 1),
474                                                  permitSet);
475                 if (pathStr.starts_with("/sys/bus/iio/devices"))
476                 {
477                     continue;
478                 }
479                 if (hwmonFile)
480                 {
481                     // To look up thresholds for these additional sensors,
482                     // match on the Index property in the threshold data
483                     // where the index comes from the sysfs file we're on,
484                     // i.e. index = 2 for temp2_input.
485                     int index = i + 1;
486                     std::vector<thresholds::Threshold> thresholds;
487 
488                     if (!parseThresholdsFromConfig(sensorData, thresholds,
489                                                    nullptr, &index))
490                     {
491                         std::cerr << "error populating thresholds for "
492                                   << sensorName << " index " << index << "\n";
493                     }
494 
495                     auto& sensor = sensors[sensorName];
496                     if (!activateOnly)
497                     {
498                         sensor = nullptr;
499                     }
500 
501                     if (sensor != nullptr)
502                     {
503                         sensor->activate(*hwmonFile, i2cDev);
504                     }
505                     else
506                     {
507                         sensor = std::make_shared<HwmonTempSensor>(
508                             *hwmonFile, sensorType, objectServer,
509                             dbusConnection, io, sensorName,
510                             std::move(thresholds), thisSensorParameters,
511                             pollRate, interfacePath, readState, i2cDev);
512                         sensor->setupRead();
513                     }
514                 }
515 
516                 hwmonName.erase(
517                     remove(hwmonName.begin(), hwmonName.end(), sensorName),
518                     hwmonName.end());
519             }
520             if (hwmonName.empty())
521             {
522                 configMap.erase(findSensorCfg);
523             }
524         }
525     });
526     std::vector<std::string> types(sensorTypes.size());
527     for (const auto& [type, dt] : sensorTypes)
528     {
529         types.push_back(type);
530     }
531     getter->getConfiguration(types);
532 }
533 
interfaceRemoved(sdbusplus::message_t & message,boost::container::flat_map<std::string,std::shared_ptr<HwmonTempSensor>> & sensors)534 void interfaceRemoved(
535     sdbusplus::message_t& message,
536     boost::container::flat_map<std::string, std::shared_ptr<HwmonTempSensor>>&
537         sensors)
538 {
539     if (message.is_method_error())
540     {
541         std::cerr << "interfacesRemoved callback method error\n";
542         return;
543     }
544 
545     sdbusplus::message::object_path path;
546     std::vector<std::string> interfaces;
547 
548     message.read(path, interfaces);
549 
550     // If the xyz.openbmc_project.Confguration.X interface was removed
551     // for one or more sensors, delete those sensor objects.
552     auto sensorIt = sensors.begin();
553     while (sensorIt != sensors.end())
554     {
555         if (sensorIt->second && (sensorIt->second->configurationPath == path) &&
556             (std::find(interfaces.begin(), interfaces.end(),
557                        sensorIt->second->configInterface) != interfaces.end()))
558         {
559             sensorIt = sensors.erase(sensorIt);
560         }
561         else
562         {
563             sensorIt++;
564         }
565     }
566 }
567 
powerStateChanged(PowerState type,bool newState,boost::container::flat_map<std::string,std::shared_ptr<HwmonTempSensor>> & sensors,boost::asio::io_context & io,sdbusplus::asio::object_server & objectServer,std::shared_ptr<sdbusplus::asio::connection> & dbusConnection)568 static void powerStateChanged(
569     PowerState type, bool newState,
570     boost::container::flat_map<std::string, std::shared_ptr<HwmonTempSensor>>&
571         sensors,
572     boost::asio::io_context& io, sdbusplus::asio::object_server& objectServer,
573     std::shared_ptr<sdbusplus::asio::connection>& dbusConnection)
574 {
575     if (newState)
576     {
577         createSensors(io, objectServer, sensors, dbusConnection, nullptr, true);
578     }
579     else
580     {
581         for (auto& [path, sensor] : sensors)
582         {
583             if (sensor != nullptr && sensor->readState == type)
584             {
585                 sensor->deactivate();
586             }
587         }
588     }
589 }
590 
main()591 int main()
592 {
593     boost::asio::io_context io;
594     auto systemBus = std::make_shared<sdbusplus::asio::connection>(io);
595     sdbusplus::asio::object_server objectServer(systemBus, true);
596     objectServer.add_manager("/xyz/openbmc_project/sensors");
597     systemBus->request_name("xyz.openbmc_project.HwmonTempSensor");
598 
599     boost::container::flat_map<std::string, std::shared_ptr<HwmonTempSensor>>
600         sensors;
601     auto sensorsChanged =
602         std::make_shared<boost::container::flat_set<std::string>>();
603 
604     auto powerCallBack = [&sensors, &io, &objectServer,
605                           &systemBus](PowerState type, bool state) {
606         powerStateChanged(type, state, sensors, io, objectServer, systemBus);
607     };
608     setupPowerMatchCallback(systemBus, powerCallBack);
609 
610     boost::asio::post(io, [&]() {
611         createSensors(io, objectServer, sensors, systemBus, nullptr, false);
612     });
613 
614     boost::asio::steady_timer filterTimer(io);
615     std::function<void(sdbusplus::message_t&)> eventHandler =
616         [&](sdbusplus::message_t& message) {
617         if (message.is_method_error())
618         {
619             std::cerr << "callback method error\n";
620             return;
621         }
622         sensorsChanged->insert(message.get_path());
623         // this implicitly cancels the timer
624         filterTimer.expires_after(std::chrono::seconds(1));
625 
626         filterTimer.async_wait([&](const boost::system::error_code& ec) {
627             if (ec == boost::asio::error::operation_aborted)
628             {
629                 /* we were canceled*/
630                 return;
631             }
632             if (ec)
633             {
634                 std::cerr << "timer error\n";
635                 return;
636             }
637             createSensors(io, objectServer, sensors, systemBus, sensorsChanged,
638                           false);
639         });
640     };
641 
642     std::vector<std::unique_ptr<sdbusplus::bus::match_t>> matches =
643         setupPropertiesChangedMatches(*systemBus, sensorTypes, eventHandler);
644     setupManufacturingModeMatch(*systemBus);
645 
646     // Watch for entity-manager to remove configuration interfaces
647     // so the corresponding sensors can be removed.
648     auto ifaceRemovedMatch = std::make_unique<sdbusplus::bus::match_t>(
649         static_cast<sdbusplus::bus_t&>(*systemBus),
650         "type='signal',member='InterfacesRemoved',arg0path='" +
651             std::string(inventoryPath) + "/'",
652         [&sensors](sdbusplus::message_t& msg) {
653         interfaceRemoved(msg, sensors);
654     });
655 
656     matches.emplace_back(std::move(ifaceRemovedMatch));
657 
658     io.run();
659 }
660