2 files changed, 526 insertions, 0 deletions
diff --git a/hal/linux/LinuxProcessPriority.cpp b/hal/linux/LinuxProcessPriority.cpp
new file mode 100644
index 0000000000..a0f72a4f38
--- /dev/null
+++ b/hal/linux/LinuxProcessPriority.cpp
@@ -0,0 +1,78 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Hal.h"
+#include "HalLog.h"
+
+#include "mozilla/Sprintf.h"
+#include "mozilla/Unused.h"
+
+#include <fcntl.h>
+#include <unistd.h>
+
+using namespace mozilla::hal;
+
+namespace mozilla::hal_impl {
+
+/* The Linux OOM score is a value computed by the kernel ranging between 0 and
+ * 1000 and indicating how likely is a process to be killed when memory is
+ * tight. The larger the value the more likely a process is to be killed. The
+ * score is computed based on the amount of memory used plus an adjustment
+ * value. We chose our adjustment values to make it likely that processes are
+ * killed in the following order:
+ *
+ * 1. preallocated processes
+ * 2. background processes
+ * 3. background processes playing video (but no audio)
+ * 4. foreground processes or processes playing or recording audio
+ * 5. the parent process
+ *
+ * At the time of writing (2022) the base score for a process consuming very
+ * little memory seems to be around ~667. Our adjustments are thus designed
+ * to ensure this order starting from a 667 baseline but trying not to go too
+ * close to the 1000 limit where they would be clamped. */
+
+const uint32_t kParentOomScoreAdjust = 0;
+const uint32_t kForegroundOomScoreAdjust = 100;
+const uint32_t kBackgroundPerceivableOomScoreAdjust = 133;
+const uint32_t kBackgroundOomScoreAdjust = 167;
+const uint32_t kPreallocOomScoreAdjust = 233;
+
+static uint32_t OomScoreAdjForPriority(ProcessPriority aPriority) {
+  switch (aPriority) {
+    case PROCESS_PRIORITY_BACKGROUND:
+      return kBackgroundOomScoreAdjust;
+    case PROCESS_PRIORITY_BACKGROUND_PERCEIVABLE:
+      return kBackgroundPerceivableOomScoreAdjust;
+    case PROCESS_PRIORITY_PREALLOC:
+      return kPreallocOomScoreAdjust;
+    case PROCESS_PRIORITY_FOREGROUND:
+      return kForegroundOomScoreAdjust;
+    default:
+      return kParentOomScoreAdjust;
+  }
+}
+
+void SetProcessPriority(int aPid, ProcessPriority aPriority) {
+  HAL_LOG("LinuxProcessPriority - SetProcessPriority(%d, %s)\n", aPid,
+          ProcessPriorityToString(aPriority));
+
+  uint32_t oomScoreAdj = OomScoreAdjForPriority(aPriority);
+
+  char path[32] = {};
+  SprintfLiteral(path, "/proc/%d/oom_score_adj", aPid);
+
+  char oomScoreAdjStr[11] = {};
+  SprintfLiteral(oomScoreAdjStr, "%d", oomScoreAdj);
+
+  int fd = open(path, O_WRONLY);
+  if (fd < 0) {
+    return;
+  }
+  const size_t len = strlen(oomScoreAdjStr);
+  Unused << write(fd, oomScoreAdjStr, len);
+  Unused << close(fd);
+}
+
+}  // namespace mozilla::hal_impl
diff --git a/hal/linux/UPowerClient.cpp b/hal/linux/UPowerClient.cpp
new file mode 100644
index 0000000000..1de38ad201
--- /dev/null
+++ b/hal/linux/UPowerClient.cpp
@@ -0,0 +1,448 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Hal.h"
+#include "HalLog.h"
+#include <dbus/dbus-glib.h>
+#include <dbus/dbus-glib-lowlevel.h>
+#include <mozilla/Attributes.h>
+#include <mozilla/dom/battery/Constants.h>
+#include "mozilla/GRefPtr.h"
+#include "mozilla/GUniquePtr.h"
+#include <cmath>
+
+using namespace mozilla::dom::battery;
+
+namespace mozilla::hal_impl {
+
+/**
+ * This is the declaration of UPowerClient class. This class is listening and
+ * communicating to upower daemon through DBus.
+ * There is no header file because this class shouldn't be public.
+ */
+class UPowerClient {
+ public:
+  static UPowerClient* GetInstance();
+
+  void BeginListening();
+  void StopListening();
+
+  double GetLevel();
+  bool IsCharging();
+  double GetRemainingTime();
+
+  ~UPowerClient();
+
+ private:
+  UPowerClient();
+
+  enum States {
+    eState_Unknown = 0,
+    eState_Charging,
+    eState_Discharging,
+    eState_Empty,
+    eState_FullyCharged,
+    eState_PendingCharge,
+    eState_PendingDischarge
+  };
+
+  /**
+   * Update the currently tracked device.
+   * @return whether everything went ok.
+   */
+  void UpdateTrackedDeviceSync();
+
+  /**
+   * Returns a hash table with the properties of aDevice.
+   */
+  already_AddRefed<GHashTable> GetDevicePropertiesSync(DBusGProxy* aProxy);
+  void GetDevicePropertiesAsync(DBusGProxy* aProxy);
+  static void GetDevicePropertiesCallback(DBusGProxy* aProxy,
+                                          DBusGProxyCall* aCall, void* aData);
+
+  /**
+   * Using the device properties (aHashTable), this method updates the member
+   * variable storing the values we care about.
+   */
+  void UpdateSavedInfo(GHashTable* aHashTable);
+
+  /**
+   * Callback used by 'DeviceChanged' signal.
+   */
+  static void DeviceChanged(DBusGProxy* aProxy, const gchar* aObjectPath,
+                            UPowerClient* aListener);
+
+  /**
+   * Callback used by 'PropertiesChanged' signal.
+   * This method is called when the the battery level changes.
+   * (Only with upower >= 0.99)
+   */
+  static void PropertiesChanged(DBusGProxy* aProxy, const gchar*, GHashTable*,
+                                char**, UPowerClient* aListener);
+
+  /**
+   * Callback called when mDBusConnection gets a signal.
+   */
+  static DBusHandlerResult ConnectionSignalFilter(DBusConnection* aConnection,
+                                                  DBusMessage* aMessage,
+                                                  void* aData);
+
+  // The DBus connection object.
+  RefPtr<DBusGConnection> mDBusConnection;
+
+  // The DBus proxy object to upower.
+  RefPtr<DBusGProxy> mUPowerProxy;
+
+  // The path of the tracked device.
+  GUniquePtr<gchar> mTrackedDevice;
+
+  // The DBusGProxy for the tracked device.
+  RefPtr<DBusGProxy> mTrackedDeviceProxy;
+
+  double mLevel;
+  bool mCharging;
+  double mRemainingTime;
+
+  static UPowerClient* sInstance;
+
+  static const guint sDeviceTypeBattery = 2;
+  static const guint64 kUPowerUnknownRemainingTime = 0;
+};
+
+/*
+ * Implementation of mozilla::hal_impl::EnableBatteryNotifications,
+ *                   mozilla::hal_impl::DisableBatteryNotifications,
+ *               and mozilla::hal_impl::GetCurrentBatteryInformation.
+ */
+
+void EnableBatteryNotifications() {
+  UPowerClient::GetInstance()->BeginListening();
+}
+
+void DisableBatteryNotifications() {
+  UPowerClient::GetInstance()->StopListening();
+}
+
+void GetCurrentBatteryInformation(hal::BatteryInformation* aBatteryInfo) {
+  UPowerClient* upowerClient = UPowerClient::GetInstance();
+
+  aBatteryInfo->level() = upowerClient->GetLevel();
+  aBatteryInfo->charging() = upowerClient->IsCharging();
+  aBatteryInfo->remainingTime() = upowerClient->GetRemainingTime();
+}
+
+/*
+ * Following is the implementation of UPowerClient.
+ */
+
+UPowerClient* UPowerClient::sInstance = nullptr;
+
+/* static */
+UPowerClient* UPowerClient::GetInstance() {
+  if (!sInstance) {
+    sInstance = new UPowerClient();
+  }
+
+  return sInstance;
+}
+
+UPowerClient::UPowerClient()
+    : mLevel(kDefaultLevel),
+      mCharging(kDefaultCharging),
+      mRemainingTime(kDefaultRemainingTime) {}
+
+UPowerClient::~UPowerClient() {
+  NS_ASSERTION(!mDBusConnection && !mUPowerProxy && !mTrackedDevice &&
+                   !mTrackedDeviceProxy,
+               "The observers have not been correctly removed! "
+               "(StopListening should have been called)");
+}
+
+void UPowerClient::BeginListening() {
+  GUniquePtr<GError> error;
+  mDBusConnection =
+      dont_AddRef(dbus_g_bus_get(DBUS_BUS_SYSTEM, getter_Transfers(error)));
+
+  if (!mDBusConnection) {
+    HAL_LOG("Failed to open connection to bus: %s\n", error->message);
+    return;
+  }
+
+  DBusConnection* dbusConnection =
+      dbus_g_connection_get_connection(mDBusConnection);
+
+  // Make sure we do not exit the entire program if DBus connection get lost.
+  dbus_connection_set_exit_on_disconnect(dbusConnection, false);
+
+  // Listening to signals the DBus connection is going to get so we will know
+  // when it is lost and we will be able to disconnect cleanly.
+  dbus_connection_add_filter(dbusConnection, ConnectionSignalFilter, this,
+                             nullptr);
+
+  mUPowerProxy = dont_AddRef(dbus_g_proxy_new_for_name(
+      mDBusConnection, "org.freedesktop.UPower", "/org/freedesktop/UPower",
+      "org.freedesktop.UPower"));
+
+  UpdateTrackedDeviceSync();
+
+  /*
+   * TODO: we should probably listen to DeviceAdded and DeviceRemoved signals.
+   * If we do that, we would have to disconnect from those in StopListening.
+   * It's not yet implemented because it requires testing hot plugging and
+   * removal of a battery.
+   */
+  dbus_g_proxy_add_signal(mUPowerProxy, "DeviceChanged", G_TYPE_STRING,
+                          G_TYPE_INVALID);
+  dbus_g_proxy_connect_signal(mUPowerProxy, "DeviceChanged",
+                              G_CALLBACK(DeviceChanged), this, nullptr);
+}
+
+void UPowerClient::StopListening() {
+  // If mDBusConnection isn't initialized, that means we are not really
+  // listening.
+  if (!mDBusConnection) {
+    return;
+  }
+
+  dbus_connection_remove_filter(
+      dbus_g_connection_get_connection(mDBusConnection), ConnectionSignalFilter,
+      this);
+
+  dbus_g_proxy_disconnect_signal(mUPowerProxy, "DeviceChanged",
+                                 G_CALLBACK(DeviceChanged), this);
+
+  mTrackedDevice = nullptr;
+
+  if (mTrackedDeviceProxy) {
+    dbus_g_proxy_disconnect_signal(mTrackedDeviceProxy, "PropertiesChanged",
+                                   G_CALLBACK(PropertiesChanged), this);
+    mTrackedDeviceProxy = nullptr;
+  }
+
+  mUPowerProxy = nullptr;
+  mDBusConnection = nullptr;
+
+  // We should now show the default values, not the latest we got.
+  mLevel = kDefaultLevel;
+  mCharging = kDefaultCharging;
+  mRemainingTime = kDefaultRemainingTime;
+}
+
+void UPowerClient::UpdateTrackedDeviceSync() {
+  GType typeGPtrArray =
+      dbus_g_type_get_collection("GPtrArray", DBUS_TYPE_G_OBJECT_PATH);
+  GPtrArray* devices = nullptr;
+
+  // Reset the current tracked device:
+  mTrackedDevice = nullptr;
+
+  // Reset the current tracked device proxy:
+  if (mTrackedDeviceProxy) {
+    dbus_g_proxy_disconnect_signal(mTrackedDeviceProxy, "PropertiesChanged",
+                                   G_CALLBACK(PropertiesChanged), this);
+    mTrackedDeviceProxy = nullptr;
+  }
+
+  GUniquePtr<GError> error;
+  // If that fails, that likely means upower isn't installed.
+  if (!dbus_g_proxy_call(mUPowerProxy, "EnumerateDevices",
+                         getter_Transfers(error), G_TYPE_INVALID, typeGPtrArray,
+                         &devices, G_TYPE_INVALID)) {
+    HAL_LOG("Error: %s\n", error->message);
+    return;
+  }
+
+  /*
+   * We are looking for the first device that is a battery.
+   * TODO: we could try to combine more than one battery.
+   */
+  for (guint i = 0; i < devices->len; ++i) {
+    GUniquePtr<gchar> devicePath(
+        static_cast<gchar*>(g_ptr_array_index(devices, i)));
+    if (mTrackedDevice) {
+      continue;
+    }
+
+    RefPtr<DBusGProxy> proxy = dont_AddRef(dbus_g_proxy_new_from_proxy(
+        mUPowerProxy, "org.freedesktop.DBus.Properties", devicePath.get()));
+
+    RefPtr<GHashTable> hashTable(GetDevicePropertiesSync(proxy));
+
+    if (g_value_get_uint(static_cast<const GValue*>(
+            g_hash_table_lookup(hashTable, "Type"))) == sDeviceTypeBattery) {
+      UpdateSavedInfo(hashTable);
+      mTrackedDevice = std::move(devicePath);
+      mTrackedDeviceProxy = std::move(proxy);
+      // Can't break here because we still need to iterate over all other
+      // devices to free them.
+    }
+  }
+
+  if (mTrackedDeviceProxy) {
+    dbus_g_proxy_add_signal(
+        mTrackedDeviceProxy, "PropertiesChanged", G_TYPE_STRING,
+        dbus_g_type_get_map("GHashTable", G_TYPE_STRING, G_TYPE_VALUE),
+        G_TYPE_STRV, G_TYPE_INVALID);
+    dbus_g_proxy_connect_signal(mTrackedDeviceProxy, "PropertiesChanged",
+                                G_CALLBACK(PropertiesChanged), this, nullptr);
+  }
+
+  g_ptr_array_free(devices, true);
+}
+
+/* static */
+void UPowerClient::DeviceChanged(DBusGProxy* aProxy, const gchar* aObjectPath,
+                                 UPowerClient* aListener) {
+  if (!aListener->mTrackedDevice) {
+    return;
+  }
+
+#if GLIB_MAJOR_VERSION >= 2 && GLIB_MINOR_VERSION >= 16
+  if (g_strcmp0(aObjectPath, aListener->mTrackedDevice.get())) {
+#else
+  if (g_ascii_strcasecmp(aObjectPath, aListener->mTrackedDevice.get())) {
+#endif
+    return;
+  }
+
+  aListener->GetDevicePropertiesAsync(aListener->mTrackedDeviceProxy);
+}
+
+/* static */
+void UPowerClient::PropertiesChanged(DBusGProxy* aProxy, const gchar*,
+                                     GHashTable*, char**,
+                                     UPowerClient* aListener) {
+  aListener->GetDevicePropertiesAsync(aListener->mTrackedDeviceProxy);
+}
+
+/* static */
+DBusHandlerResult UPowerClient::ConnectionSignalFilter(
+    DBusConnection* aConnection, DBusMessage* aMessage, void* aData) {
+  if (dbus_message_is_signal(aMessage, DBUS_INTERFACE_LOCAL, "Disconnected")) {
+    static_cast<UPowerClient*>(aData)->StopListening();
+    // We do not return DBUS_HANDLER_RESULT_HANDLED here because the connection
+    // might be shared and some other filters might want to do something.
+  }
+
+  return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+}
+
+already_AddRefed<GHashTable> UPowerClient::GetDevicePropertiesSync(
+    DBusGProxy* aProxy) {
+  GUniquePtr<GError> error;
+  RefPtr<GHashTable> hashTable;
+  GType typeGHashTable =
+      dbus_g_type_get_map("GHashTable", G_TYPE_STRING, G_TYPE_VALUE);
+  if (!dbus_g_proxy_call(aProxy, "GetAll", getter_Transfers(error),
+                         G_TYPE_STRING, "org.freedesktop.UPower.Device",
+                         G_TYPE_INVALID, typeGHashTable,
+                         hashTable.StartAssignment(), G_TYPE_INVALID)) {
+    HAL_LOG("Error: %s\n", error->message);
+    return nullptr;
+  }
+
+  return hashTable.forget();
+}
+
+/* static */
+void UPowerClient::GetDevicePropertiesCallback(DBusGProxy* aProxy,
+                                               DBusGProxyCall* aCall,
+                                               void* aData) {
+  GUniquePtr<GError> error;
+  RefPtr<GHashTable> hashTable;
+  GType typeGHashTable =
+      dbus_g_type_get_map("GHashTable", G_TYPE_STRING, G_TYPE_VALUE);
+  if (!dbus_g_proxy_end_call(aProxy, aCall, getter_Transfers(error),
+                             typeGHashTable, hashTable.StartAssignment(),
+                             G_TYPE_INVALID)) {
+    HAL_LOG("Error: %s\n", error->message);
+  } else {
+    sInstance->UpdateSavedInfo(hashTable);
+    hal::NotifyBatteryChange(hal::BatteryInformation(
+        sInstance->mLevel, sInstance->mCharging, sInstance->mRemainingTime));
+    g_hash_table_unref(hashTable);
+  }
+}
+
+void UPowerClient::GetDevicePropertiesAsync(DBusGProxy* aProxy) {
+  dbus_g_proxy_begin_call(aProxy, "GetAll", GetDevicePropertiesCallback,
+                          nullptr, nullptr, G_TYPE_STRING,
+                          "org.freedesktop.UPower.Device", G_TYPE_INVALID);
+}
+
+void UPowerClient::UpdateSavedInfo(GHashTable* aHashTable) {
+  bool isFull = false;
+
+  /*
+   * State values are confusing...
+   * First of all, after looking at upower sources (0.9.13), it seems that
+   * PendingDischarge and PendingCharge are not used.
+   * In addition, FullyCharged and Empty states are not clear because we do not
+   * know if the battery is actually charging or not. Those values come directly
+   * from sysfs (in the Linux kernel) which have four states: "Empty", "Full",
+   * "Charging" and "Discharging". In sysfs, "Empty" and "Full" are also only
+   * related to the level, not to the charging state.
+   * In this code, we are going to assume that Full means charging and Empty
+   * means discharging because if that is not the case, the state should not
+   * last a long time (actually, it should disappear at the following update).
+   * It might be even very hard to see real cases where the state is Empty and
+   * the battery is charging or the state is Full and the battery is discharging
+   * given that plugging/unplugging the battery should have an impact on the
+   * level.
+   */
+  switch (g_value_get_uint(
+      static_cast<const GValue*>(g_hash_table_lookup(aHashTable, "State")))) {
+    case eState_Unknown:
+      mCharging = kDefaultCharging;
+      break;
+    case eState_FullyCharged:
+      isFull = true;
+      [[fallthrough]];
+    case eState_Charging:
+    case eState_PendingCharge:
+      mCharging = true;
+      break;
+    case eState_Discharging:
+    case eState_Empty:
+    case eState_PendingDischarge:
+      mCharging = false;
+      break;
+  }
+
+  /*
+   * The battery level might be very close to 100% (like 99%) without
+   * increasing. It seems that upower sets the battery state as 'full' in that
+   * case so we should trust it and not even try to get the value.
+   */
+  if (isFull) {
+    mLevel = 1.0;
+  } else {
+    mLevel = round(g_value_get_double(static_cast<const GValue*>(
+                 g_hash_table_lookup(aHashTable, "Percentage")))) *
+             0.01;
+  }
+
+  if (isFull) {
+    mRemainingTime = 0;
+  } else {
+    mRemainingTime = mCharging
+                         ? g_value_get_int64(static_cast<const GValue*>(
+                               g_hash_table_lookup(aHashTable, "TimeToFull")))
+                         : g_value_get_int64(static_cast<const GValue*>(
+                               g_hash_table_lookup(aHashTable, "TimeToEmpty")));
+
+    if (mRemainingTime == kUPowerUnknownRemainingTime) {
+      mRemainingTime = kUnknownRemainingTime;
+    }
+  }
+}
+
+double UPowerClient::GetLevel() { return mLevel; }
+
+bool UPowerClient::IsCharging() { return mCharging; }
+
+double UPowerClient::GetRemainingTime() { return mRemainingTime; }
+
+}  // namespace mozilla::hal_impl