diff --git a/xkb.cpp b/xkb.cpp
index 74db4410f..150978cda 100644
--- a/xkb.cpp
+++ b/xkb.cpp
@@ -1,520 +1,553 @@
 /********************************************************************
  KWin - the KDE window manager
  This file is part of the KDE project.
 
 Copyright (C) 2013, 2016, 2017 Martin Gräßlin <mgraesslin@kde.org>
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 #include "xkb.h"
 #include "xkb_qt_mapping.h"
 #include "utils.h"
 // frameworks
 #include <KConfigGroup>
 // KWayland
 #include <KWayland/Server/seat_interface.h>
 // Qt
 #include <QTemporaryFile>
 #include <QKeyEvent>
 // xkbcommon
 #include <xkbcommon/xkbcommon.h>
 #include <xkbcommon/xkbcommon-compose.h>
 #include <xkbcommon/xkbcommon-keysyms.h>
 // system
 #include <sys/mman.h>
 #include <unistd.h>
 
 Q_LOGGING_CATEGORY(KWIN_XKB, "kwin_xkbcommon", QtCriticalMsg)
 
 namespace KWin
 {
 
 static void xkbLogHandler(xkb_context *context, xkb_log_level priority, const char *format, va_list args)
 {
     Q_UNUSED(context)
     char buf[1024];
     if (std::vsnprintf(buf, 1023, format, args) <= 0) {
         return;
     }
     switch (priority) {
     case XKB_LOG_LEVEL_DEBUG:
         qCDebug(KWIN_XKB) << "XKB:" << buf;
         break;
     case XKB_LOG_LEVEL_INFO:
         qCInfo(KWIN_XKB) << "XKB:" << buf;
         break;
     case XKB_LOG_LEVEL_WARNING:
         qCWarning(KWIN_XKB) << "XKB:" << buf;
         break;
     case XKB_LOG_LEVEL_ERROR:
     case XKB_LOG_LEVEL_CRITICAL:
     default:
         qCCritical(KWIN_XKB) << "XKB:" << buf;
         break;
     }
 }
 
 Xkb::Xkb(QObject *parent)
     : QObject(parent)
     , m_context(xkb_context_new(static_cast<xkb_context_flags>(0)))
     , m_keymap(NULL)
     , m_state(NULL)
     , m_shiftModifier(0)
     , m_capsModifier(0)
     , m_controlModifier(0)
     , m_altModifier(0)
     , m_metaModifier(0)
     , m_numLock(0)
     , m_capsLock(0)
     , m_scrollLock(0)
     , m_modifiers(Qt::NoModifier)
     , m_consumedModifiers(Qt::NoModifier)
     , m_keysym(XKB_KEY_NoSymbol)
     , m_leds()
 {
     qRegisterMetaType<KWin::Xkb::LEDs>();
     if (!m_context) {
         qCDebug(KWIN_XKB) << "Could not create xkb context";
     } else {
         xkb_context_set_log_level(m_context, XKB_LOG_LEVEL_DEBUG);
         xkb_context_set_log_fn(m_context, &xkbLogHandler);
 
         // get locale as described in xkbcommon doc
         // cannot use QLocale as it drops the modifier part
         QByteArray locale = qgetenv("LC_ALL");
         if (locale.isEmpty()) {
             locale = qgetenv("LC_CTYPE");
         }
         if (locale.isEmpty()) {
             locale = qgetenv("LANG");
         }
         if (locale.isEmpty()) {
             locale = QByteArrayLiteral("C");
         }
 
         m_compose.table = xkb_compose_table_new_from_locale(m_context, locale.constData(), XKB_COMPOSE_COMPILE_NO_FLAGS);
         if (m_compose.table) {
             m_compose.state = xkb_compose_state_new(m_compose.table, XKB_COMPOSE_STATE_NO_FLAGS);
         }
     }
 }
 
 Xkb::~Xkb()
 {
     xkb_compose_state_unref(m_compose.state);
     xkb_compose_table_unref(m_compose.table);
     xkb_state_unref(m_state);
     xkb_keymap_unref(m_keymap);
     xkb_context_unref(m_context);
 }
 
 void Xkb::reconfigure()
 {
     if (!m_context) {
         return;
     }
 
     xkb_keymap *keymap = nullptr;
     if (!qEnvironmentVariableIsSet("KWIN_XKB_DEFAULT_KEYMAP")) {
         keymap = loadKeymapFromConfig();
     }
     if (!keymap) {
         qCDebug(KWIN_XKB) << "Could not create xkb keymap from configuration";
         keymap = loadDefaultKeymap();
     }
     if (keymap) {
         updateKeymap(keymap);
     } else {
         qCDebug(KWIN_XKB) << "Could not create default xkb keymap";
     }
 }
 
+static bool stringIsEmptyOrNull(const char *str)
+{
+    return str == nullptr || str[0] == '\0';
+}
+
+/**
+ * libxkbcommon uses secure_getenv to read the XKB_DEFAULT_* variables.
+ * As kwin_wayland may have the CAP_SET_NICE capability, it returns nullptr
+ * so we need to do it ourselves (see xkb_context_sanitize_rule_names).
+**/
+static void applyEnvironmentRules(xkb_rule_names &ruleNames)
+{
+    if (stringIsEmptyOrNull(ruleNames.rules)) {
+        ruleNames.rules = getenv("XKB_DEFAULT_RULES");
+    }
+
+    if (stringIsEmptyOrNull(ruleNames.model)) {
+        ruleNames.model = getenv("XKB_DEFAULT_MODEL");
+    }
+
+    if (stringIsEmptyOrNull(ruleNames.layout)) {
+        ruleNames.layout = getenv("XKB_DEFAULT_LAYOUT");
+        ruleNames.variant = getenv("XKB_DEFAULT_VARIANT");
+    }
+
+    if (ruleNames.options == nullptr) {
+        ruleNames.options = getenv("XKB_DEFAULT_OPTIONS");
+    }
+}
+
 xkb_keymap *Xkb::loadKeymapFromConfig()
 {
     // load config
     if (!m_config) {
         return nullptr;
     }
     const KConfigGroup config = m_config->group("Layout");
     const QByteArray model = config.readEntry("Model", "pc104").toLocal8Bit();
     const QByteArray layout = config.readEntry("LayoutList", "").toLocal8Bit();
     const QByteArray options = config.readEntry("Options", "").toLocal8Bit();
 
     xkb_rule_names ruleNames = {
         .rules = nullptr,
         .model = model.constData(),
         .layout = layout.constData(),
         .variant = nullptr,
         .options = options.constData()
     };
+    applyEnvironmentRules(ruleNames);
     return xkb_keymap_new_from_names(m_context, &ruleNames, XKB_KEYMAP_COMPILE_NO_FLAGS);
 }
 
 xkb_keymap *Xkb::loadDefaultKeymap()
 {
-    return xkb_keymap_new_from_names(m_context, nullptr, XKB_KEYMAP_COMPILE_NO_FLAGS);
+    xkb_rule_names ruleNames = {};
+    applyEnvironmentRules(ruleNames);
+    return xkb_keymap_new_from_names(m_context, &ruleNames, XKB_KEYMAP_COMPILE_NO_FLAGS);
 }
 
 void Xkb::installKeymap(int fd, uint32_t size)
 {
     if (!m_context) {
         return;
     }
     char *map = reinterpret_cast<char*>(mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0));
     if (map == MAP_FAILED) {
         return;
     }
     xkb_keymap *keymap = xkb_keymap_new_from_string(m_context, map, XKB_KEYMAP_FORMAT_TEXT_V1, XKB_MAP_COMPILE_PLACEHOLDER);
     munmap(map, size);
     if (!keymap) {
         qCDebug(KWIN_XKB) << "Could not map keymap from file";
         return;
     }
     updateKeymap(keymap);
 }
 
 void Xkb::updateKeymap(xkb_keymap *keymap)
 {
     Q_ASSERT(keymap);
     xkb_state *state = xkb_state_new(keymap);
     if (!state) {
         qCDebug(KWIN_XKB) << "Could not create XKB state";
         xkb_keymap_unref(keymap);
         return;
     }
     // now release the old ones
     xkb_state_unref(m_state);
     xkb_keymap_unref(m_keymap);
 
     m_keymap = keymap;
     m_state = state;
 
     m_shiftModifier   = xkb_keymap_mod_get_index(m_keymap, XKB_MOD_NAME_SHIFT);
     m_capsModifier    = xkb_keymap_mod_get_index(m_keymap, XKB_MOD_NAME_CAPS);
     m_controlModifier = xkb_keymap_mod_get_index(m_keymap, XKB_MOD_NAME_CTRL);
     m_altModifier     = xkb_keymap_mod_get_index(m_keymap, XKB_MOD_NAME_ALT);
     m_metaModifier    = xkb_keymap_mod_get_index(m_keymap, XKB_MOD_NAME_LOGO);
 
     m_numLock         = xkb_keymap_led_get_index(m_keymap, XKB_LED_NAME_NUM);
     m_capsLock        = xkb_keymap_led_get_index(m_keymap, XKB_LED_NAME_CAPS);
     m_scrollLock      = xkb_keymap_led_get_index(m_keymap, XKB_LED_NAME_SCROLL);
 
     m_currentLayout = xkb_state_serialize_layout(m_state, XKB_STATE_LAYOUT_EFFECTIVE);
 
     m_modifierState.depressed = xkb_state_serialize_mods(m_state, xkb_state_component(XKB_STATE_MODS_DEPRESSED));
     m_modifierState.latched = xkb_state_serialize_mods(m_state, xkb_state_component(XKB_STATE_MODS_LATCHED));
     m_modifierState.locked = xkb_state_serialize_mods(m_state, xkb_state_component(XKB_STATE_MODS_LOCKED));
 
     createKeymapFile();
     forwardModifiers();
 }
 
 void Xkb::createKeymapFile()
 {
     if (!m_seat) {
         return;
     }
     // TODO: uninstall keymap on server?
     if (!m_keymap) {
         return;
     }
 
     ScopedCPointer<char> keymapString(xkb_keymap_get_as_string(m_keymap, XKB_KEYMAP_FORMAT_TEXT_V1));
     if (keymapString.isNull()) {
         return;
     }
     const uint size = qstrlen(keymapString.data()) + 1;
 
     QTemporaryFile *tmp = new QTemporaryFile(this);
     if (!tmp->open()) {
         delete tmp;
         return;
     }
     unlink(tmp->fileName().toUtf8().constData());
     if (!tmp->resize(size)) {
         delete tmp;
         return;
     }
     uchar *address = tmp->map(0, size);
     if (!address) {
         return;
     }
     if (qstrncpy(reinterpret_cast<char*>(address), keymapString.data(), size) == nullptr) {
         delete tmp;
         return;
     }
     m_seat->setKeymap(tmp->handle(), size);
 }
 
 void Xkb::updateModifiers(uint32_t modsDepressed, uint32_t modsLatched, uint32_t modsLocked, uint32_t group)
 {
     if (!m_keymap || !m_state) {
         return;
     }
     xkb_state_update_mask(m_state, modsDepressed, modsLatched, modsLocked, 0, 0, group);
     updateModifiers();
     forwardModifiers();
 }
 
 void Xkb::updateKey(uint32_t key, InputRedirection::KeyboardKeyState state)
 {
     if (!m_keymap || !m_state) {
         return;
     }
     xkb_state_update_key(m_state, key + 8, static_cast<xkb_key_direction>(state));
     if (state == InputRedirection::KeyboardKeyPressed) {
         const auto sym = toKeysym(key);
         if (m_compose.state && xkb_compose_state_feed(m_compose.state, sym) == XKB_COMPOSE_FEED_ACCEPTED) {
             switch (xkb_compose_state_get_status(m_compose.state)) {
             case XKB_COMPOSE_NOTHING:
                 m_keysym = sym;
                 break;
             case XKB_COMPOSE_COMPOSED:
                 m_keysym = xkb_compose_state_get_one_sym(m_compose.state);
                 break;
             default:
                 m_keysym = XKB_KEY_NoSymbol;
                 break;
             }
         } else {
             m_keysym = sym;
         }
     }
     updateModifiers();
     updateConsumedModifiers(key);
 }
 
 void Xkb::updateModifiers()
 {
     Qt::KeyboardModifiers mods = Qt::NoModifier;
     if (xkb_state_mod_index_is_active(m_state, m_shiftModifier, XKB_STATE_MODS_EFFECTIVE) == 1 ||
         xkb_state_mod_index_is_active(m_state, m_capsModifier, XKB_STATE_MODS_EFFECTIVE) == 1) {
         mods |= Qt::ShiftModifier;
     }
     if (xkb_state_mod_index_is_active(m_state, m_altModifier, XKB_STATE_MODS_EFFECTIVE) == 1) {
         mods |= Qt::AltModifier;
     }
     if (xkb_state_mod_index_is_active(m_state, m_controlModifier, XKB_STATE_MODS_EFFECTIVE) == 1) {
         mods |= Qt::ControlModifier;
     }
     if (xkb_state_mod_index_is_active(m_state, m_metaModifier, XKB_STATE_MODS_EFFECTIVE) == 1) {
         mods |= Qt::MetaModifier;
     }
     m_modifiers = mods;
 
     // update LEDs
     LEDs leds;
     if (xkb_state_led_index_is_active(m_state, m_numLock) == 1) {
         leds = leds | LED::NumLock;
     }
     if (xkb_state_led_index_is_active(m_state, m_capsLock) == 1) {
         leds = leds | LED::CapsLock;
     }
     if (xkb_state_led_index_is_active(m_state, m_scrollLock) == 1) {
         leds = leds | LED::ScrollLock;
     }
     if (m_leds != leds) {
         m_leds = leds;
         emit ledsChanged(m_leds);
     }
 
     m_currentLayout = xkb_state_serialize_layout(m_state, XKB_STATE_LAYOUT_EFFECTIVE);
     m_modifierState.depressed = xkb_state_serialize_mods(m_state, xkb_state_component(XKB_STATE_MODS_DEPRESSED));
     m_modifierState.latched = xkb_state_serialize_mods(m_state, xkb_state_component(XKB_STATE_MODS_LATCHED));
     m_modifierState.locked = xkb_state_serialize_mods(m_state, xkb_state_component(XKB_STATE_MODS_LOCKED));
 }
 
 void Xkb::forwardModifiers()
 {
     if (!m_seat) {
         return;
     }
     m_seat->updateKeyboardModifiers(m_modifierState.depressed,
                                                      m_modifierState.latched,
                                                      m_modifierState.locked,
                                                      m_currentLayout);
 }
 
 QString Xkb::layoutName() const
 {
     return layoutName(m_currentLayout);
 }
 
 QString Xkb::layoutName(xkb_layout_index_t layout) const
 {
     if (!m_keymap) {
         return QString{};
     }
     return QString::fromLocal8Bit(xkb_keymap_layout_get_name(m_keymap, layout));
 }
 
 QMap<xkb_layout_index_t, QString> Xkb::layoutNames() const
 {
     QMap<xkb_layout_index_t, QString> layouts;
     const auto size = m_keymap ? xkb_keymap_num_layouts(m_keymap) : 0u;
     for (xkb_layout_index_t i = 0; i < size; i++) {
         layouts.insert(i, layoutName(i));
     }
     return layouts;
 }
 
 void Xkb::updateConsumedModifiers(uint32_t key)
 {
     Qt::KeyboardModifiers mods = Qt::NoModifier;
     if (xkb_state_mod_index_is_consumed2(m_state, key + 8, m_shiftModifier, XKB_CONSUMED_MODE_GTK) == 1) {
         mods |= Qt::ShiftModifier;
     }
     if (xkb_state_mod_index_is_consumed2(m_state, key + 8, m_altModifier, XKB_CONSUMED_MODE_GTK) == 1) {
         mods |= Qt::AltModifier;
     }
     if (xkb_state_mod_index_is_consumed2(m_state, key + 8, m_controlModifier, XKB_CONSUMED_MODE_GTK) == 1) {
         mods |= Qt::ControlModifier;
     }
     if (xkb_state_mod_index_is_consumed2(m_state, key + 8, m_metaModifier, XKB_CONSUMED_MODE_GTK) == 1) {
         mods |= Qt::MetaModifier;
     }
     m_consumedModifiers = mods;
 }
 
 Qt::KeyboardModifiers Xkb::modifiersRelevantForGlobalShortcuts() const
 {
     if (!m_state) {
         return Qt::NoModifier;
     }
     Qt::KeyboardModifiers mods = Qt::NoModifier;
     if (xkb_state_mod_index_is_active(m_state, m_shiftModifier, XKB_STATE_MODS_EFFECTIVE) == 1) {
         mods |= Qt::ShiftModifier;
     }
     if (xkb_state_mod_index_is_active(m_state, m_altModifier, XKB_STATE_MODS_EFFECTIVE) == 1) {
         mods |= Qt::AltModifier;
     }
     if (xkb_state_mod_index_is_active(m_state, m_controlModifier, XKB_STATE_MODS_EFFECTIVE) == 1) {
         mods |= Qt::ControlModifier;
     }
     if (xkb_state_mod_index_is_active(m_state, m_metaModifier, XKB_STATE_MODS_EFFECTIVE) == 1) {
         mods |= Qt::MetaModifier;
     }
 
     Qt::KeyboardModifiers consumedMods = m_consumedModifiers;
     if ((mods & Qt::ShiftModifier) && (consumedMods == Qt::ShiftModifier)) {
         // test whether current keysym is a letter
         // in that case the shift should be removed from the consumed modifiers again
         // otherwise it would not be possible to trigger e.g. Shift+W as a shortcut
         // see BUG: 370341
         if (QChar(toQtKey(m_keysym)).isLetter()) {
             consumedMods = Qt::KeyboardModifiers();
         }
     }
 
     return mods & ~consumedMods;
 }
 
 xkb_keysym_t Xkb::toKeysym(uint32_t key)
 {
     if (!m_state) {
         return XKB_KEY_NoSymbol;
     }
     return xkb_state_key_get_one_sym(m_state, key + 8);
 }
 
 QString Xkb::toString(xkb_keysym_t keysym)
 {
     if (!m_state || keysym == XKB_KEY_NoSymbol) {
         return QString();
     }
     QByteArray byteArray(7, 0);
     int ok = xkb_keysym_to_utf8(keysym, byteArray.data(), byteArray.size());
     if (ok == -1 || ok == 0) {
         return QString();
     }
     return QString::fromUtf8(byteArray.constData());
 }
 
 Qt::Key Xkb::toQtKey(xkb_keysym_t keysym) const
 {
     return xkbToQtKey(keysym);
 }
 
 xkb_keysym_t Xkb::fromQtKey(Qt::Key key, Qt::KeyboardModifiers mods) const
 {
     return qtKeyToXkb(key, mods);
 }
 
 xkb_keysym_t Xkb::fromKeyEvent(QKeyEvent *event) const
 {
     xkb_keysym_t sym = xkb_keysym_from_name(event->text().toUtf8().constData(), XKB_KEYSYM_NO_FLAGS);
     if (sym == XKB_KEY_NoSymbol) {
         // mapping from text failed, try mapping through KKeyServer
         sym = fromQtKey(Qt::Key(event->key() & ~Qt::KeyboardModifierMask), event->modifiers());
     }
     return sym;
 }
 
 bool Xkb::shouldKeyRepeat(quint32 key) const
 {
     if (!m_keymap) {
         return false;
     }
     return xkb_keymap_key_repeats(m_keymap, key + 8) != 0;
 }
 
 void Xkb::switchToNextLayout()
 {
     if (!m_keymap || !m_state) {
         return;
     }
     const xkb_layout_index_t numLayouts = xkb_keymap_num_layouts(m_keymap);
     const xkb_layout_index_t nextLayout = (xkb_state_serialize_layout(m_state, XKB_STATE_LAYOUT_EFFECTIVE) + 1) % numLayouts;
     switchToLayout(nextLayout);
 }
 
 void Xkb::switchToPreviousLayout()
 {
     if (!m_keymap || !m_state) {
         return;
     }
     const xkb_layout_index_t previousLayout = m_currentLayout == 0 ? numberOfLayouts() - 1 : m_currentLayout -1;
     switchToLayout(previousLayout);
 }
 
 void Xkb::switchToLayout(xkb_layout_index_t layout)
 {
     if (!m_keymap || !m_state) {
         return;
     }
     if (layout >= numberOfLayouts()) {
         return;
     }
     const xkb_mod_mask_t depressed = xkb_state_serialize_mods(m_state, xkb_state_component(XKB_STATE_MODS_DEPRESSED));
     const xkb_mod_mask_t latched = xkb_state_serialize_mods(m_state, xkb_state_component(XKB_STATE_MODS_LATCHED));
     const xkb_mod_mask_t locked = xkb_state_serialize_mods(m_state, xkb_state_component(XKB_STATE_MODS_LOCKED));
     xkb_state_update_mask(m_state, depressed, latched, locked, 0, 0, layout);
     updateModifiers();
     forwardModifiers();
 }
 
 quint32 Xkb::numberOfLayouts() const
 {
     if (!m_keymap) {
         return 0;
     }
     return xkb_keymap_num_layouts(m_keymap);
 }
 
 void Xkb::setSeat(KWayland::Server::SeatInterface *seat)
 {
     m_seat = QPointer<KWayland::Server::SeatInterface>(seat);
 }
 
 }