diff --git a/base/Android.bp b/base/Android.bp
index 71bf154..3d80d97 100644
--- a/base/Android.bp
+++ b/base/Android.bp
@@ -48,6 +48,7 @@
         "file.cpp",
         "logging.cpp",
         "parsenetaddress.cpp",
+        "properties.cpp",
         "quick_exit.cpp",
         "stringprintf.cpp",
         "strings.cpp",
@@ -58,9 +59,6 @@
     shared_libs: ["liblog"],
     target: {
         android: {
-            srcs: [
-                "properties.cpp",
-            ],
             sanitize: {
                 misc_undefined: ["integer"],
             },
@@ -130,6 +128,7 @@
         "parsedouble_test.cpp",
         "parseint_test.cpp",
         "parsenetaddress_test.cpp",
+        "properties_test.cpp",
         "quick_exit_test.cpp",
         "scopeguard_test.cpp",
         "stringprintf_test.cpp",
@@ -139,7 +138,6 @@
     ],
     target: {
         android: {
-            srcs: ["properties_test.cpp"],
             sanitize: {
                 misc_undefined: ["integer"],
             },
diff --git a/base/include/android-base/properties.h b/base/include/android-base/properties.h
index 041586c..3a05143 100644
--- a/base/include/android-base/properties.h
+++ b/base/include/android-base/properties.h
@@ -19,10 +19,6 @@
 
 #include <sys/cdefs.h>
 
-#if !defined(__BIONIC__)
-#error Only bionic supports system properties.
-#endif
-
 #include <chrono>
 #include <limits>
 #include <string>
@@ -62,14 +58,18 @@
 // Waits for the system property `key` to have the value `expected_value`.
 // Times out after `relative_timeout`.
 // Returns true on success, false on timeout.
+#if defined(__BIONIC__)
 bool WaitForProperty(const std::string& key, const std::string& expected_value,
                      std::chrono::milliseconds relative_timeout = std::chrono::milliseconds::max());
+#endif
 
 // Waits for the system property `key` to be created.
 // Times out after `relative_timeout`.
 // Returns true on success, false on timeout.
+#if defined(__BIONIC__)
 bool WaitForPropertyCreation(const std::string& key, std::chrono::milliseconds relative_timeout =
                                                          std::chrono::milliseconds::max());
+#endif
 
 } // namespace base
 } // namespace android
diff --git a/base/properties.cpp b/base/properties.cpp
index 6cf43f9..d5a5918 100644
--- a/base/properties.cpp
+++ b/base/properties.cpp
@@ -14,16 +14,18 @@
  * limitations under the License.
  */
 
-#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
-
 #include "android-base/properties.h"
 
+#if defined(__BIONIC__)
+#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
 #include <sys/system_properties.h>
 #include <sys/_system_properties.h>
+#endif
 
 #include <algorithm>
 #include <chrono>
 #include <limits>
+#include <map>
 #include <string>
 
 #include <android-base/parseint.h>
@@ -31,24 +33,6 @@
 namespace android {
 namespace base {
 
-std::string GetProperty(const std::string& key, const std::string& default_value) {
-  const prop_info* pi = __system_property_find(key.c_str());
-  if (pi == nullptr) return default_value;
-
-  std::string property_value;
-  __system_property_read_callback(pi,
-                                  [](void* cookie, const char*, const char* value, unsigned) {
-                                    auto property_value = reinterpret_cast<std::string*>(cookie);
-                                    *property_value = value;
-                                  },
-                                  &property_value);
-
-  // If the property exists but is empty, also return the default value.
-  // Since we can't remove system properties, "empty" is traditionally
-  // the same as "missing" (this was true for cutils' property_get).
-  return property_value.empty() ? default_value : property_value;
-}
-
 bool GetBoolProperty(const std::string& key, bool default_value) {
   std::string value = GetProperty(key, "");
   if (value == "1" || value == "y" || value == "yes" || value == "on" || value == "true") {
@@ -85,10 +69,43 @@
 template uint32_t GetUintProperty(const std::string&, uint32_t, uint32_t);
 template uint64_t GetUintProperty(const std::string&, uint64_t, uint64_t);
 
+#if !defined(__BIONIC__)
+static std::map<std::string, std::string>& g_properties = *new std::map<std::string, std::string>;
+static int __system_property_set(const char* key, const char* value) {
+  g_properties[key] = value;
+  return 0;
+}
+#endif
+
+std::string GetProperty(const std::string& key, const std::string& default_value) {
+  std::string property_value;
+#if defined(__BIONIC__)
+  const prop_info* pi = __system_property_find(key.c_str());
+  if (pi == nullptr) return default_value;
+
+  __system_property_read_callback(pi,
+                                  [](void* cookie, const char*, const char* value, unsigned) {
+                                    auto property_value = reinterpret_cast<std::string*>(cookie);
+                                    *property_value = value;
+                                  },
+                                  &property_value);
+#else
+  auto it = g_properties.find(key);
+  if (it == g_properties.end()) return default_value;
+  property_value = it->second;
+#endif
+  // If the property exists but is empty, also return the default value.
+  // Since we can't remove system properties, "empty" is traditionally
+  // the same as "missing" (this was true for cutils' property_get).
+  return property_value.empty() ? default_value : property_value;
+}
+
 bool SetProperty(const std::string& key, const std::string& value) {
   return (__system_property_set(key.c_str(), value.c_str()) == 0);
 }
 
+#if defined(__BIONIC__)
+
 struct WaitForPropertyData {
   bool done;
   const std::string* expected_value;
@@ -175,5 +192,7 @@
   return (WaitForPropertyCreation(key, relative_timeout, start_time) != nullptr);
 }
 
+#endif
+
 }  // namespace base
 }  // namespace android
diff --git a/base/properties_test.cpp b/base/properties_test.cpp
index de5f3dc..e7d4880 100644
--- a/base/properties_test.cpp
+++ b/base/properties_test.cpp
@@ -23,7 +23,9 @@
 #include <string>
 #include <thread>
 
-using namespace std::chrono_literals;
+#if !defined(_WIN32)
+using namespace std::literals;
+#endif
 
 TEST(properties, smoke) {
   android::base::SetProperty("debug.libbase.property_test", "hello");
@@ -126,6 +128,7 @@
 TEST(properties, GetUintProperty_uint64_t) { CheckGetUintProperty<uint64_t>(); }
 
 TEST(properties, WaitForProperty) {
+#if defined(__BIONIC__)
   std::atomic<bool> flag{false};
   std::thread thread([&]() {
     std::this_thread::sleep_for(100ms);
@@ -138,9 +141,13 @@
   flag = true;
   ASSERT_TRUE(android::base::WaitForProperty("debug.libbase.WaitForProperty_test", "b", 1s));
   thread.join();
+#else
+  GTEST_LOG_(INFO) << "This test does nothing on the host.\n";
+#endif
 }
 
 TEST(properties, WaitForProperty_timeout) {
+#if defined(__BIONIC__)
   auto t0 = std::chrono::steady_clock::now();
   ASSERT_FALSE(android::base::WaitForProperty("debug.libbase.WaitForProperty_timeout_test", "a",
                                               200ms));
@@ -149,9 +156,13 @@
   ASSERT_GE(std::chrono::duration_cast<std::chrono::milliseconds>(t1 - t0), 200ms);
   // Upper bounds on timing are inherently flaky, but let's try...
   ASSERT_LT(std::chrono::duration_cast<std::chrono::milliseconds>(t1 - t0), 600ms);
+#else
+  GTEST_LOG_(INFO) << "This test does nothing on the host.\n";
+#endif
 }
 
 TEST(properties, WaitForProperty_MaxTimeout) {
+#if defined(__BIONIC__)
   std::atomic<bool> flag{false};
   std::thread thread([&]() {
     android::base::SetProperty("debug.libbase.WaitForProperty_test", "a");
@@ -165,9 +176,13 @@
   // Test that this does not immediately return false due to overflow issues with the timeout.
   ASSERT_TRUE(android::base::WaitForProperty("debug.libbase.WaitForProperty_test", "b"));
   thread.join();
+#else
+  GTEST_LOG_(INFO) << "This test does nothing on the host.\n";
+#endif
 }
 
 TEST(properties, WaitForProperty_NegativeTimeout) {
+#if defined(__BIONIC__)
   std::atomic<bool> flag{false};
   std::thread thread([&]() {
     android::base::SetProperty("debug.libbase.WaitForProperty_test", "a");
@@ -181,9 +196,13 @@
   // Assert that this immediately returns with a negative timeout
   ASSERT_FALSE(android::base::WaitForProperty("debug.libbase.WaitForProperty_test", "b", -100ms));
   thread.join();
+#else
+  GTEST_LOG_(INFO) << "This test does nothing on the host.\n";
+#endif
 }
 
 TEST(properties, WaitForPropertyCreation) {
+#if defined(__BIONIC__)
   std::thread thread([&]() {
     std::this_thread::sleep_for(100ms);
     android::base::SetProperty("debug.libbase.WaitForPropertyCreation_test", "a");
@@ -192,9 +211,13 @@
   ASSERT_TRUE(android::base::WaitForPropertyCreation(
           "debug.libbase.WaitForPropertyCreation_test", 1s));
   thread.join();
+#else
+  GTEST_LOG_(INFO) << "This test does nothing on the host.\n";
+#endif
 }
 
 TEST(properties, WaitForPropertyCreation_timeout) {
+#if defined(__BIONIC__)
   auto t0 = std::chrono::steady_clock::now();
   ASSERT_FALSE(android::base::WaitForPropertyCreation(
           "debug.libbase.WaitForPropertyCreation_timeout_test", 200ms));
@@ -203,4 +226,7 @@
   ASSERT_GE(std::chrono::duration_cast<std::chrono::milliseconds>(t1 - t0), 200ms);
   // Upper bounds on timing are inherently flaky, but let's try...
   ASSERT_LT(std::chrono::duration_cast<std::chrono::milliseconds>(t1 - t0), 600ms);
+#else
+  GTEST_LOG_(INFO) << "This test does nothing on the host.\n";
+#endif
 }
diff --git a/init/Android.bp b/init/Android.bp
index a3083c1..517847c 100644
--- a/init/Android.bp
+++ b/init/Android.bp
@@ -170,6 +170,7 @@
     srcs: [
         "devices_test.cpp",
         "init_test.cpp",
+        "keychords_test.cpp",
         "persistent_properties_test.cpp",
         "property_service_test.cpp",
         "property_type_test.cpp",
diff --git a/init/action.cpp b/init/action.cpp
index f782b51..11335ca 100644
--- a/init/action.cpp
+++ b/init/action.cpp
@@ -18,16 +18,11 @@
 
 #include <android-base/chrono_utils.h>
 #include <android-base/logging.h>
+#include <android-base/properties.h>
 #include <android-base/strings.h>
 
 #include "util.h"
 
-#if defined(__ANDROID__)
-#include <android-base/properties.h>
-#else
-#include "host_init_stubs.h"
-#endif
-
 using android::base::Join;
 
 namespace android {
diff --git a/init/action_parser.cpp b/init/action_parser.cpp
index a2c9671..8a4b518 100644
--- a/init/action_parser.cpp
+++ b/init/action_parser.cpp
@@ -16,16 +16,11 @@
 
 #include "action_parser.h"
 
+#include <android-base/properties.h>
 #include <android-base/strings.h>
 
 #include "stable_properties.h"
 
-#if defined(__ANDROID__)
-#include <android-base/properties.h>
-#else
-#include "host_init_stubs.h"
-#endif
-
 using android::base::GetBoolProperty;
 using android::base::StartsWith;
 
diff --git a/init/host_init_stubs.cpp b/init/host_init_stubs.cpp
index 4451ac8..c40a254 100644
--- a/init/host_init_stubs.cpp
+++ b/init/host_init_stubs.cpp
@@ -22,20 +22,6 @@
 }
 
 namespace android {
-namespace base {
-
-std::string GetProperty(const std::string&, const std::string& default_value) {
-    return default_value;
-}
-
-bool GetBoolProperty(const std::string&, bool default_value) {
-    return default_value;
-}
-
-}  // namespace base
-}  // namespace android
-
-namespace android {
 namespace init {
 
 // init.h
diff --git a/init/host_init_stubs.h b/init/host_init_stubs.h
index bb241af..f0e1f07 100644
--- a/init/host_init_stubs.h
+++ b/init/host_init_stubs.h
@@ -29,16 +29,6 @@
 // unistd.h
 int setgroups(size_t __size, const gid_t* __list);
 
-// android-base/properties.h
-namespace android {
-namespace base {
-
-std::string GetProperty(const std::string& key, const std::string& default_value);
-bool GetBoolProperty(const std::string& key, bool default_value);
-
-}  // namespace base
-}  // namespace android
-
 namespace android {
 namespace init {
 
diff --git a/init/init.cpp b/init/init.cpp
index 5652c5e..82648d9 100644
--- a/init/init.cpp
+++ b/init/init.cpp
@@ -553,22 +553,30 @@
     }
 }
 
-void HandleKeychord(int id) {
+void HandleKeychord(const std::vector<int>& keycodes) {
     // Only handle keychords if adb is enabled.
     std::string adb_enabled = android::base::GetProperty("init.svc.adbd", "");
-    if (adb_enabled == "running") {
-        Service* svc = ServiceList::GetInstance().FindService(id, &Service::keychord_id);
-        if (svc) {
-            LOG(INFO) << "Starting service '" << svc->name() << "' from keychord " << id;
+    if (adb_enabled != "running") {
+        LOG(WARNING) << "Not starting service for keychord " << android::base::Join(keycodes, ' ')
+                     << " because ADB is disabled";
+        return;
+    }
+
+    auto found = false;
+    for (const auto& service : ServiceList::GetInstance()) {
+        auto svc = service.get();
+        if (svc->keycodes() == keycodes) {
+            found = true;
+            LOG(INFO) << "Starting service '" << svc->name() << "' from keychord "
+                      << android::base::Join(keycodes, ' ');
             if (auto result = svc->Start(); !result) {
-                LOG(ERROR) << "Could not start service '" << svc->name() << "' from keychord " << id
-                           << ": " << result.error();
+                LOG(ERROR) << "Could not start service '" << svc->name() << "' from keychord "
+                           << android::base::Join(keycodes, ' ') << ": " << result.error();
             }
-        } else {
-            LOG(ERROR) << "Service for keychord " << id << " not found";
         }
-    } else {
-        LOG(WARNING) << "Not starting service for keychord " << id << " because ADB is disabled";
+    }
+    if (!found) {
+        LOG(ERROR) << "Service for keychord " << android::base::Join(keycodes, ' ') << " not found";
     }
 }
 
@@ -753,7 +761,7 @@
     am.QueueBuiltinAction(
         [&epoll, &keychords](const BuiltinArguments& args) -> Result<Success> {
             for (const auto& svc : ServiceList::GetInstance()) {
-                svc->set_keychord_id(keychords.GetId(svc->keycodes()));
+                keychords.Register(svc->keycodes());
             }
             keychords.Start(&epoll, HandleKeychord);
             return Success();
diff --git a/init/keychords.cpp b/init/keychords.cpp
index 9aa8b2a..1af06dd 100644
--- a/init/keychords.cpp
+++ b/init/keychords.cpp
@@ -37,7 +37,7 @@
 namespace android {
 namespace init {
 
-Keychords::Keychords() : epoll_(nullptr), count_(0), inotify_fd_(-1) {}
+Keychords::Keychords() : epoll_(nullptr), inotify_fd_(-1) {}
 
 Keychords::~Keychords() noexcept {
     if (inotify_fd_ >= 0) {
@@ -108,23 +108,22 @@
     }
 }
 
-Keychords::Entry::Entry(const std::vector<int>& keycodes, int id)
-    : keycodes(keycodes), id(id), notified(false) {}
+Keychords::Entry::Entry() : notified(false) {}
 
 void Keychords::LambdaCheck() {
-    for (auto& e : entries_) {
+    for (auto& [keycodes, entry] : entries_) {
         auto found = true;
-        for (auto& code : e.keycodes) {
+        for (auto& code : keycodes) {
             if (!current_.GetBit(code)) {
-                e.notified = false;
+                entry.notified = false;
                 found = false;
                 break;
             }
         }
         if (!found) continue;
-        if (e.notified) continue;
-        e.notified = true;
-        handler_(e.id);
+        if (entry.notified) continue;
+        entry.notified = true;
+        handler_(keycodes);
     }
 }
 
@@ -158,8 +157,8 @@
 #endif
 
     Keychords::Mask mask;
-    for (auto& e : entries_) {
-        for (auto& code : e.keycodes) {
+    for (auto& [keycodes, entry] : entries_) {
+        for (auto& code : keycodes) {
             mask.resize(code);
             mask.SetBit(code);
         }
@@ -271,17 +270,15 @@
     }
 }
 
-int Keychords::GetId(const std::vector<int>& keycodes) {
-    if (keycodes.empty()) return 0;
-    ++count_;
-    entries_.emplace_back(Entry(keycodes, count_));
-    return count_;
+void Keychords::Register(const std::vector<int>& keycodes) {
+    if (keycodes.empty()) return;
+    entries_.try_emplace(keycodes, Entry());
 }
 
-void Keychords::Start(Epoll* epoll, std::function<void(int)> handler) {
+void Keychords::Start(Epoll* epoll, std::function<void(const std::vector<int>&)> handler) {
     epoll_ = epoll;
     handler_ = handler;
-    if (count_) GeteventOpenDevice();
+    if (entries_.size()) GeteventOpenDevice();
 }
 
 }  // namespace init
diff --git a/init/keychords.h b/init/keychords.h
index 74a9195..00ed205 100644
--- a/init/keychords.h
+++ b/init/keychords.h
@@ -36,8 +36,8 @@
     Keychords& operator=(Keychords&&) = delete;
     ~Keychords() noexcept;
 
-    int GetId(const std::vector<int>& keycodes);
-    void Start(Epoll* epoll, std::function<void(int)> handler);
+    void Register(const std::vector<int>& keycodes);
+    void Start(Epoll* epoll, std::function<void(const std::vector<int>&)> handler);
 
   private:
     // Bit management
@@ -65,10 +65,8 @@
     };
 
     struct Entry {
-        Entry(const std::vector<int>& keycodes, int id);
+        Entry();
 
-        const std::vector<int> keycodes;
-        const int id;
         bool notified;
     };
 
@@ -84,12 +82,11 @@
     void GeteventCloseDevice(const std::string& device);
 
     Epoll* epoll_;
-    std::function<void(int)> handler_;
+    std::function<void(const std::vector<int>&)> handler_;
 
     std::map<std::string, int> registration_;
 
-    int count_;
-    std::vector<Entry> entries_;
+    std::map<const std::vector<int>, Entry> entries_;
 
     Mask current_;
 
diff --git a/init/keychords_test.cpp b/init/keychords_test.cpp
new file mode 100644
index 0000000..c8c47a8
--- /dev/null
+++ b/init/keychords_test.cpp
@@ -0,0 +1,348 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "keychords.h"
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <linux/input.h>
+#include <linux/uinput.h>
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <chrono>
+#include <set>
+#include <string>
+#include <vector>
+
+#include <android-base/properties.h>
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
+#include <gtest/gtest.h>
+
+#include "epoll.h"
+
+using namespace std::chrono_literals;
+
+namespace android {
+namespace init {
+
+namespace {
+
+// This class is used to inject keys.
+class EventHandler {
+  public:
+    EventHandler();
+    EventHandler(const EventHandler&) = delete;
+    EventHandler(EventHandler&&);
+    EventHandler& operator=(const EventHandler&) = delete;
+    EventHandler& operator=(EventHandler&&);
+    ~EventHandler() noexcept;
+
+    bool init();
+
+    bool send(struct input_event& e);
+    bool send(uint16_t type, uint16_t code, uint16_t value);
+    bool send(uint16_t code, bool value);
+
+  private:
+    int fd_;
+};
+
+EventHandler::EventHandler() : fd_(-1) {}
+
+EventHandler::EventHandler(EventHandler&& rval) : fd_(rval.fd_) {
+    rval.fd_ = -1;
+}
+
+EventHandler& EventHandler::operator=(EventHandler&& rval) {
+    fd_ = rval.fd_;
+    rval.fd_ = -1;
+    return *this;
+}
+
+EventHandler::~EventHandler() {
+    if (fd_ == -1) return;
+    ::ioctl(fd_, UI_DEV_DESTROY);
+    ::close(fd_);
+}
+
+bool EventHandler::init() {
+    if (fd_ != -1) return true;
+    auto fd = TEMP_FAILURE_RETRY(::open("/dev/uinput", O_WRONLY | O_NONBLOCK | O_CLOEXEC));
+    if (fd == -1) return false;
+    if (::ioctl(fd, UI_SET_EVBIT, EV_KEY) == -1) {
+        ::close(fd);
+        return false;
+    }
+
+    static const struct uinput_user_dev u = {
+        .name = "com.google.android.init.test",
+        .id.bustype = BUS_VIRTUAL,
+        .id.vendor = 0x1AE0,   // Google
+        .id.product = 0x494E,  // IN
+        .id.version = 1,
+    };
+    if (TEMP_FAILURE_RETRY(::write(fd, &u, sizeof(u))) != sizeof(u)) {
+        ::close(fd);
+        return false;
+    }
+
+    // all keys
+    for (uint16_t i = 0; i < KEY_MAX; ++i) {
+        if (::ioctl(fd, UI_SET_KEYBIT, i) == -1) {
+            ::close(fd);
+            return false;
+        }
+    }
+    if (::ioctl(fd, UI_DEV_CREATE) == -1) {
+        ::close(fd);
+        return false;
+    }
+    fd_ = fd;
+    return true;
+}
+
+bool EventHandler::send(struct input_event& e) {
+    gettimeofday(&e.time, nullptr);
+    return TEMP_FAILURE_RETRY(::write(fd_, &e, sizeof(e))) == sizeof(e);
+}
+
+bool EventHandler::send(uint16_t type, uint16_t code, uint16_t value) {
+    struct input_event e = {.type = type, .code = code, .value = value};
+    return send(e);
+}
+
+bool EventHandler::send(uint16_t code, bool value) {
+    return (code < KEY_MAX) && init() && send(EV_KEY, code, value) && send(EV_SYN, SYN_REPORT, 0);
+}
+
+std::string InitFds(const char* prefix, pid_t pid = getpid()) {
+    std::string ret;
+
+    std::string init_fds("/proc/");
+    init_fds += std::to_string(pid) + "/fd";
+    std::unique_ptr<DIR, decltype(&closedir)> fds(opendir(init_fds.c_str()), closedir);
+    if (!fds) return ret;
+
+    dirent* entry;
+    while ((entry = readdir(fds.get()))) {
+        if (entry->d_name[0] == '.') continue;
+        std::string devname = init_fds + '/' + entry->d_name;
+        char buf[256];
+        auto retval = readlink(devname.c_str(), buf, sizeof(buf) - 1);
+        if ((retval < 0) || (size_t(retval) >= (sizeof(buf) - 1))) continue;
+        buf[retval] = '\0';
+        if (!android::base::StartsWith(buf, prefix)) continue;
+        if (ret.size() != 0) ret += ",";
+        ret += buf;
+    }
+    return ret;
+}
+
+std::string InitInputFds() {
+    return InitFds("/dev/input/");
+}
+
+std::string InitInotifyFds() {
+    return InitFds("anon_inode:inotify");
+}
+
+// NB: caller (this series of tests, or conversely the service parser in init)
+// is responsible for validation, sorting and uniqueness of the chords, so no
+// fuzzing is advised.
+
+const std::vector<int> escape_chord = {KEY_ESC};
+const std::vector<int> triple1_chord = {KEY_BACKSPACE, KEY_VOLUMEDOWN, KEY_VOLUMEUP};
+const std::vector<int> triple2_chord = {KEY_VOLUMEDOWN, KEY_VOLUMEUP, KEY_BACK};
+
+const std::vector<const std::vector<int>> empty_chords;
+const std::vector<const std::vector<int>> chords = {
+    escape_chord,
+    triple1_chord,
+    triple2_chord,
+};
+
+class TestFrame {
+  public:
+    TestFrame(const std::vector<const std::vector<int>>& chords, EventHandler* ev = nullptr);
+
+    void RelaxForMs(std::chrono::milliseconds wait = 1ms);
+
+    void SetChord(int key, bool value = true);
+    void SetChords(const std::vector<int>& chord, bool value = true);
+    void ClrChord(int key);
+    void ClrChords(const std::vector<int>& chord);
+
+    bool IsOnlyChord(const std::vector<int>& chord) const;
+    bool IsNoChord() const;
+    bool IsChord(const std::vector<int>& chord) const;
+    void WaitForChord(const std::vector<int>& chord);
+
+    std::string Format() const;
+
+  private:
+    static std::string Format(const std::vector<const std::vector<int>>& chords);
+
+    Epoll epoll_;
+    Keychords keychords_;
+    std::vector<const std::vector<int>> keycodes_;
+    EventHandler* ev_;
+};
+
+TestFrame::TestFrame(const std::vector<const std::vector<int>>& chords, EventHandler* ev)
+    : ev_(ev) {
+    if (!epoll_.Open()) return;
+    for (const auto& keycodes : chords) keychords_.Register(keycodes);
+    keychords_.Start(&epoll_, [this](const std::vector<int>& keycodes) {
+        this->keycodes_.emplace_back(keycodes);
+    });
+}
+
+void TestFrame::RelaxForMs(std::chrono::milliseconds wait) {
+    epoll_.Wait(wait);
+}
+
+void TestFrame::SetChord(int key, bool value) {
+    ASSERT_TRUE(!!ev_);
+    RelaxForMs();
+    EXPECT_TRUE(ev_->send(key, value));
+}
+
+void TestFrame::SetChords(const std::vector<int>& chord, bool value) {
+    ASSERT_TRUE(!!ev_);
+    for (auto& key : chord) SetChord(key, value);
+    RelaxForMs();
+}
+
+void TestFrame::ClrChord(int key) {
+    ASSERT_TRUE(!!ev_);
+    SetChord(key, false);
+}
+
+void TestFrame::ClrChords(const std::vector<int>& chord) {
+    ASSERT_TRUE(!!ev_);
+    SetChords(chord, false);
+}
+
+bool TestFrame::IsOnlyChord(const std::vector<int>& chord) const {
+    auto ret = false;
+    for (const auto& keycode : keycodes_) {
+        if (keycode != chord) return false;
+        ret = true;
+    }
+    return ret;
+}
+
+bool TestFrame::IsNoChord() const {
+    return keycodes_.empty();
+}
+
+bool TestFrame::IsChord(const std::vector<int>& chord) const {
+    for (const auto& keycode : keycodes_) {
+        if (keycode == chord) return true;
+    }
+    return false;
+}
+
+void TestFrame::WaitForChord(const std::vector<int>& chord) {
+    for (int retry = 1000; retry && !IsChord(chord); --retry) RelaxForMs();
+}
+
+std::string TestFrame::Format(const std::vector<const std::vector<int>>& chords) {
+    std::string ret("{");
+    if (!chords.empty()) {
+        ret += android::base::Join(chords.front(), ' ');
+        for (auto it = std::next(chords.begin()); it != chords.end(); ++it) {
+            ret += ',';
+            ret += android::base::Join(*it, ' ');
+        }
+    }
+    return ret + '}';
+}
+
+std::string TestFrame::Format() const {
+    return Format(keycodes_);
+}
+
+}  // namespace
+
+TEST(keychords, not_instantiated) {
+    TestFrame test_frame(empty_chords);
+    EXPECT_TRUE(InitInotifyFds().size() == 0);
+}
+
+TEST(keychords, instantiated) {
+    // Test if a valid set of chords results in proper instantiation of the
+    // underlying mechanisms for /dev/input/ attachment.
+    TestFrame test_frame(chords);
+    EXPECT_TRUE(InitInotifyFds().size() != 0);
+}
+
+TEST(keychords, init_inotify) {
+    std::string before(InitInputFds());
+
+    TestFrame test_frame(chords);
+
+    EventHandler ev;
+    EXPECT_TRUE(ev.init());
+
+    for (int retry = 1000; retry && before == InitInputFds(); --retry) test_frame.RelaxForMs();
+    std::string after(InitInputFds());
+    EXPECT_NE(before, after);
+}
+
+TEST(keychords, key) {
+    EventHandler ev;
+    EXPECT_TRUE(ev.init());
+    TestFrame test_frame(chords, &ev);
+
+    test_frame.SetChords(escape_chord);
+    test_frame.WaitForChord(escape_chord);
+    test_frame.ClrChords(escape_chord);
+    EXPECT_TRUE(test_frame.IsOnlyChord(escape_chord))
+        << "expected only " << android::base::Join(escape_chord, ' ') << " got "
+        << test_frame.Format();
+}
+
+TEST(keychords, keys_in_series) {
+    EventHandler ev;
+    EXPECT_TRUE(ev.init());
+    TestFrame test_frame(chords, &ev);
+
+    for (auto& key : triple1_chord) {
+        test_frame.SetChord(key);
+        test_frame.ClrChord(key);
+    }
+    test_frame.WaitForChord(triple1_chord);
+    EXPECT_TRUE(test_frame.IsNoChord()) << "expected nothing got " << test_frame.Format();
+}
+
+TEST(keychords, keys_in_parallel) {
+    EventHandler ev;
+    EXPECT_TRUE(ev.init());
+    TestFrame test_frame(chords, &ev);
+
+    test_frame.SetChords(triple2_chord);
+    test_frame.WaitForChord(triple2_chord);
+    test_frame.ClrChords(triple2_chord);
+    EXPECT_TRUE(test_frame.IsOnlyChord(triple2_chord))
+        << "expected only " << android::base::Join(triple2_chord, ' ') << " got "
+        << test_frame.Format();
+}
+
+}  // namespace init
+}  // namespace android
diff --git a/init/service.cpp b/init/service.cpp
index 5778a93..565cae7 100644
--- a/init/service.cpp
+++ b/init/service.cpp
@@ -33,6 +33,7 @@
 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/parseint.h>
+#include <android-base/properties.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
 #include <android-base/unique_fd.h>
@@ -47,8 +48,6 @@
 #if defined(__ANDROID__)
 #include <sys/system_properties.h>
 
-#include <android-base/properties.h>
-
 #include "init.h"
 #include "property_service.h"
 #else
@@ -229,7 +228,6 @@
       seclabel_(seclabel),
       onrestart_(false, subcontext_for_restart_commands, "<Service '" + name + "' onrestart>", 0,
                  "onrestart", {}),
-      keychord_id_(0),
       ioprio_class_(IoSchedClass_NONE),
       ioprio_pri_(0),
       priority_(0),
@@ -549,7 +547,7 @@
             for (auto& key : keycodes_) {
                 if (key == code) return Error() << "duplicate keycode: " << args[i];
             }
-            keycodes_.emplace_back(code);
+            keycodes_.insert(std::upper_bound(keycodes_.begin(), keycodes_.end(), code), code);
         } else {
             return Error() << "invalid keycode: " << args[i];
         }
diff --git a/init/service.h b/init/service.h
index cbfd52f..ea79a07 100644
--- a/init/service.h
+++ b/init/service.h
@@ -108,8 +108,6 @@
     const std::vector<gid_t>& supp_gids() const { return supp_gids_; }
     const std::string& seclabel() const { return seclabel_; }
     const std::vector<int>& keycodes() const { return keycodes_; }
-    int keychord_id() const { return keychord_id_; }
-    void set_keychord_id(int keychord_id) { keychord_id_ = keychord_id; }
     IoSchedClass ioprio_class() const { return ioprio_class_; }
     int ioprio_pri() const { return ioprio_pri_; }
     const std::set<std::string>& interfaces() const { return interfaces_; }
@@ -199,9 +197,8 @@
 
     std::set<std::string> interfaces_;  // e.g. some.package.foo@1.0::IBaz/instance-name
 
-    // keycodes for triggering this service via /dev/keychord
+    // keycodes for triggering this service via /dev/input/input*
     std::vector<int> keycodes_;
-    int keychord_id_;
 
     IoSchedClass ioprio_class_;
     int ioprio_pri_;
diff --git a/init/service_test.cpp b/init/service_test.cpp
index b43c2e9..194aa2b 100644
--- a/init/service_test.cpp
+++ b/init/service_test.cpp
@@ -46,7 +46,6 @@
     EXPECT_EQ(0U, service_in_old_memory->uid());
     EXPECT_EQ(0U, service_in_old_memory->gid());
     EXPECT_EQ(0U, service_in_old_memory->namespace_flags());
-    EXPECT_EQ(0, service_in_old_memory->keychord_id());
     EXPECT_EQ(IoSchedClass_NONE, service_in_old_memory->ioprio_class());
     EXPECT_EQ(0, service_in_old_memory->ioprio_pri());
     EXPECT_EQ(0, service_in_old_memory->priority());
@@ -66,7 +65,6 @@
     EXPECT_EQ(0U, service_in_old_memory2->uid());
     EXPECT_EQ(0U, service_in_old_memory2->gid());
     EXPECT_EQ(0U, service_in_old_memory2->namespace_flags());
-    EXPECT_EQ(0, service_in_old_memory2->keychord_id());
     EXPECT_EQ(IoSchedClass_NONE, service_in_old_memory2->ioprio_class());
     EXPECT_EQ(0, service_in_old_memory2->ioprio_pri());
     EXPECT_EQ(0, service_in_old_memory2->priority());
diff --git a/init/util.cpp b/init/util.cpp
index 4455b2e..5f2b87d 100644
--- a/init/util.cpp
+++ b/init/util.cpp
@@ -33,6 +33,7 @@
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
+#include <android-base/properties.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
 #include <android-base/unique_fd.h>
@@ -43,8 +44,6 @@
 #include "reboot.h"
 
 #if defined(__ANDROID__)
-#include <android-base/properties.h>
-
 #include "selinux.h"
 #else
 #include "host_init_stubs.h"
diff --git a/libmemunreachable/README.md b/libmemunreachable/README.md
index 6d9141a..9cc0c9b 100644
--- a/libmemunreachable/README.md
+++ b/libmemunreachable/README.md
@@ -44,7 +44,7 @@
 
 ### C++ interface ###
 
-####`bool GetUnreachableMemory(UnreachableMemoryInfo& info, size_t limit = 100)`####
+#### `bool GetUnreachableMemory(UnreachableMemoryInfo& info, size_t limit = 100)` ####
 Updates an `UnreachableMemoryInfo` object with information on leaks, including details on up to `limit` leaks.  Returns true if leak detection succeeded.
 
 #### `std::string GetUnreachableMemoryString(bool log_contents = false, size_t limit = 100)` ####
diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
index 58295fa..1cebb5d 100644
--- a/libprocessgroup/processgroup.cpp
+++ b/libprocessgroup/processgroup.cpp
@@ -39,18 +39,14 @@
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
-#ifdef __ANDROID__
 #include <android-base/properties.h>
-#endif
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
 #include <private/android_filesystem_config.h>
 
 #include <processgroup/processgroup.h>
 
-#ifdef __ANDROID__
 using android::base::GetBoolProperty;
-#endif
 using android::base::StartsWith;
 using android::base::StringPrintf;
 using android::base::WriteStringToFile;
@@ -68,15 +64,10 @@
 static const std::string& GetCgroupRootPath() {
     static std::string cgroup_root_path;
     std::call_once(init_path_flag, [&]() {
-#ifdef __ANDROID__
         // low-ram devices use per-app memcg by default, unlike high-end ones
         bool low_ram_device = GetBoolProperty("ro.config.low_ram", false);
         bool per_app_memcg =
             GetBoolProperty("ro.config.per_app_memcg", low_ram_device);
-#else
-        // host does not support Android properties
-        bool per_app_memcg = false;
-#endif
         if (per_app_memcg) {
             // Check if mem cgroup is mounted, only then check for
             // write-access to avoid SELinux denials