v4l2: use serial id

Change-Id: I7f4d6e5baef04b99a2cf1435aa6848aff7bd84df

src/media/video/v4l2/video_device_monitor_impl.cpp

@@ -82,33 +82,11 @@ private:
 };
 
 std::string
-getDeviceString(udev* udev, const std::string& dev_path)
+getDeviceString(struct udev_device* udev_device)
 {
-    std::string unique_device_string;
-    struct stat statbuf;
-    if (stat(dev_path.c_str(), &statbuf) < 0) {
-        return {};
-    }
-    auto type = S_ISBLK(statbuf.st_mode) ? 'b' : S_ISCHR(statbuf.st_mode) ? 'c' : 0;
-
-    auto opened_dev = udev_device_new_from_devnum(udev, type, statbuf.st_rdev);
-    auto dev = opened_dev;
-
-    while (dev != nullptr) {
-        auto serial = udev_device_get_sysattr_value(dev, "serial");
-        if (nullptr == serial) {
-            dev = udev_device_get_parent(dev);
-        } else {
-            unique_device_string += udev_device_get_sysattr_value(dev, "idVendor");
-            unique_device_string += udev_device_get_sysattr_value(dev, "idProduct");
-            unique_device_string += serial;
-            break;
-        }
-    }
-    if (opened_dev) {
-        udev_device_unref(opened_dev);
-    }
-    return unique_device_string;
+    if (auto serial = udev_device_get_property_value(udev_device, "ID_SERIAL"))
+        return serial;
+    throw std::invalid_argument("No ID_SERIAL detected");
 }
 
 static int
@@ -167,14 +145,14 @@ VideoDeviceMonitorImpl::VideoDeviceMonitorImpl(VideoDeviceMonitor* monitor)
                 // udev_device_get_devnode will fail
                 continue;
             }
-            auto unique_name = getDeviceString(udev_, path);
+            try {
+                auto unique_name = getDeviceString(dev);
                 JAMI_DBG("udev: adding device with id %s", unique_name.c_str());
                 std::map<std::string, std::string> info = {{"devPath", path}};
                 std::vector<std::map<std::string, std::string>> devInfo = {info};
-            try {
                 monitor_->addDevice(unique_name, &devInfo);
                 currentPathToId_.emplace(path, unique_name);
-            } catch (const std::runtime_error& e) {
+            } catch (const std::exception& e) {
                 JAMI_ERR("%s", e.what());
             }
         }
@@ -253,19 +231,16 @@ VideoDeviceMonitorImpl::run()
                     // udev_device_get_devnode will fail
                     break;
                 }
-                auto unique_name = getDeviceString(udev_, path);
+                try {
+                    auto unique_name = getDeviceString(dev);
 
                     const char* action = udev_device_get_action(dev);
                     if (!strcmp(action, "add")) {
                         JAMI_DBG("udev: adding device with id %s", unique_name.c_str());
                         std::map<std::string, std::string> info = {{"devPath", path}};
                         std::vector<std::map<std::string, std::string>> devInfo = {info};
-                    try {
                         monitor_->addDevice(unique_name, &devInfo);
                         currentPathToId_.emplace(path, unique_name);
-                    } catch (const std::runtime_error& e) {
-                        JAMI_ERR("%s", e.what());
-                    }
                     } else if (!strcmp(action, "remove")) {
                         auto it = currentPathToId_.find(path);
                         if (it != currentPathToId_.end()) {
@@ -278,6 +253,9 @@ VideoDeviceMonitorImpl::run()
                             monitor_->removeDevice(path);
                         }
                     }
+                } catch (const std::exception& e) {
+                    JAMI_ERR("%s", e.what());
+                }
             }
             udev_device_unref(dev);
             break;