healthd: refactor healthd code to split into 'charger' and 'healthd'

This splits healthd code into 2 pieces as described below.

charger - statically linked executable in /sbin
 - responsible for charger-mode UI
 - battery/charger  monitoring in recovery/charger-mode.

healthd - dynamically linked (*mostly*) executable in /system/bin
 - responsible for battery / charger monitoring in Android
 - runs 'batteryproperties' service.

Both currently use libhealthd STATIC HALs. However, this now paves
way for the healthd (android) HAL to be a shared library that can
be trebelized.

   text    data     bss     dec     hex filename
 733356   15312   33864  782532   bf0c4 root/sbin/charger
  55943   10392     192   66527   103df system/bin/healthd
 789299   25704   34056  849059   cf4a3 (TOTALS)

Test: Tested recovery, charge-only and android boot with new binaries
with and without STATIC HAL.

Change-Id: I80f94948dda44d466f172d234b3fcc9064ef2476
Signed-off-by: Sandeep Patil <sspatil@google.com>

5 files changed, 420 insertions, 351 deletions

diff --git a/healthd/Android.mk b/healthd/Android.mk
index 08475f311..5a6303e32 100644
--- a/healthd/Android.mk
+++ b/healthd/Android.mk
@@ -88,7 +88,8 @@ LOCAL_CHARGER_NO_UI := true
 endif
 
 LOCAL_SRC_FILES := \
-	healthd.cpp
+    healthd_common.cpp \
+    charger.cpp \
 
 LOCAL_MODULE := charger
 LOCAL_MODULE_TAGS := optional
@@ -109,11 +110,8 @@ LOCAL_CFLAGS += -DBOARD_PERIODIC_CHORES_INTERVAL_SLOW=$(BOARD_PERIODIC_CHORES_IN
 endif
 
 LOCAL_STATIC_LIBRARIES := \
-    libhealthd_android \
     libhealthd_charger \
     libbatterymonitor \
-    libbatteryservice \
-    libbinder \
     libbase \
     libutils \
     libcutils \
@@ -173,7 +171,8 @@ endif # LOCAL_CHARGER_NO_UI
 include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES := \
-	healthd.cpp
+    healthd_common.cpp \
+    healthd.cpp \
 
 LOCAL_MODULE := healthd
 LOCAL_MODULE_TAGS := optional
@@ -188,7 +187,6 @@ endif
 
 LOCAL_STATIC_LIBRARIES := \
     libhealthd_android \
-    libhealthd_charger \
     libbatterymonitor \
     libbatteryservice \
 
@@ -200,10 +198,6 @@ LOCAL_SHARED_LIBRARIES := \
     liblog \
     libm \
     libc \
-    libminui \
-    libpng \
-    libz \
-    libsuspend \
 
 LOCAL_HAL_STATIC_LIBRARIES := libhealthd
 include $(BUILD_EXECUTABLE)
diff --git a/healthd/charger.cpp b/healthd/charger.cpp
new file mode 100644
index 000000000..5a8fe1a8b
--- /dev/null
+++ b/healthd/charger.cpp
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#define LOG_TAG "charger"
+#define KLOG_LEVEL 6
+
+#include <healthd/healthd.h>
+
+#include <stdlib.h>
+#include <string.h>
+#include <cutils/klog.h>
+
+using namespace android;
+
+// main healthd loop
+extern int healthd_main(void);
+
+// Charger mode
+
+extern void healthd_mode_charger_init(struct healthd_config *config);
+extern int healthd_mode_charger_preparetowait(void);
+extern void healthd_mode_charger_heartbeat(void);
+extern void healthd_mode_charger_battery_update(
+    struct android::BatteryProperties *props);
+
+// NOPs for modes that need no special action
+
+static void healthd_mode_nop_init(struct healthd_config *config);
+static int healthd_mode_nop_preparetowait(void);
+static void healthd_mode_nop_heartbeat(void);
+static void healthd_mode_nop_battery_update(
+    struct android::BatteryProperties *props);
+
+static struct healthd_mode_ops healthd_nops = {
+    .init = healthd_mode_nop_init,
+    .preparetowait = healthd_mode_nop_preparetowait,
+    .heartbeat = healthd_mode_nop_heartbeat,
+    .battery_update = healthd_mode_nop_battery_update,
+};
+
+#ifdef CHARGER_NO_UI
+static struct healthd_mode_ops charger_ops = healthd_nops;
+#else
+static struct healthd_mode_ops charger_ops = {
+    .init = healthd_mode_charger_init,
+    .preparetowait = healthd_mode_charger_preparetowait,
+    .heartbeat = healthd_mode_charger_heartbeat,
+    .battery_update = healthd_mode_charger_battery_update,
+};
+#endif
+
+static void healthd_mode_nop_init(struct healthd_config* /*config*/) {
+}
+
+static int healthd_mode_nop_preparetowait(void) {
+    return -1;
+}
+
+static void healthd_mode_nop_heartbeat(void) {
+}
+
+static void healthd_mode_nop_battery_update(
+    struct android::BatteryProperties* /*props*/) {
+}
+
+int main(int argc, char **argv) {
+    int ch;
+
+    healthd_mode_ops = &charger_ops;
+
+    while ((ch = getopt(argc, argv, "cr")) != -1) {
+        switch (ch) {
+            case 'c':
+                // -c is now a noop
+                break;
+            case 'r':
+                // force nops for recovery
+                healthd_mode_ops = &healthd_nops;
+                break;
+            case '?':
+            default:
+                KLOG_ERROR(LOG_TAG, "Unrecognized charger option: %c\n",
+                        optopt);
+                exit(1);
+        }
+    }
+
+    return healthd_main();
+}
diff --git a/healthd/healthd.cpp b/healthd/healthd.cpp
index aa6735d71..1ec8c2d8c 100644
--- a/healthd/healthd.cpp
+++ b/healthd/healthd.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2013 The Android Open Source Project
+ * Copyright (C) 2016 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.
@@ -18,369 +18,35 @@
 #define KLOG_LEVEL 6
 
 #include <healthd/healthd.h>
-#include <healthd/BatteryMonitor.h>
 
-#include <errno.h>
-#include <libgen.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
-#include <batteryservice/BatteryService.h>
 #include <cutils/klog.h>
-#include <cutils/uevent.h>
-#include <sys/epoll.h>
-#include <sys/timerfd.h>
-#include <utils/Errors.h>
 
 using namespace android;
 
-#ifndef BOARD_PERIODIC_CHORES_INTERVAL_FAST
-  // Periodic chores fast interval in seconds
-  #define DEFAULT_PERIODIC_CHORES_INTERVAL_FAST (60 * 1)
-#else
-  #define DEFAULT_PERIODIC_CHORES_INTERVAL_FAST (BOARD_PERIODIC_CHORES_INTERVAL_FAST)
-#endif
-
-#ifndef BOARD_PERIODIC_CHORES_INTERVAL_SLOW
-  // Periodic chores fast interval in seconds
-  #define DEFAULT_PERIODIC_CHORES_INTERVAL_SLOW (60 * 10)
-#else
-  #define DEFAULT_PERIODIC_CHORES_INTERVAL_SLOW (BOARD_PERIODIC_CHORES_INTERVAL_SLOW)
-#endif
-
-static struct healthd_config healthd_config = {
-    .periodic_chores_interval_fast = DEFAULT_PERIODIC_CHORES_INTERVAL_FAST,
-    .periodic_chores_interval_slow = DEFAULT_PERIODIC_CHORES_INTERVAL_SLOW,
-    .batteryStatusPath = String8(String8::kEmptyString),
-    .batteryHealthPath = String8(String8::kEmptyString),
-    .batteryPresentPath = String8(String8::kEmptyString),
-    .batteryCapacityPath = String8(String8::kEmptyString),
-    .batteryVoltagePath = String8(String8::kEmptyString),
-    .batteryTemperaturePath = String8(String8::kEmptyString),
-    .batteryTechnologyPath = String8(String8::kEmptyString),
-    .batteryCurrentNowPath = String8(String8::kEmptyString),
-    .batteryCurrentAvgPath = String8(String8::kEmptyString),
-    .batteryChargeCounterPath = String8(String8::kEmptyString),
-    .batteryFullChargePath = String8(String8::kEmptyString),
-    .batteryCycleCountPath = String8(String8::kEmptyString),
-    .energyCounter = NULL,
-    .boot_min_cap = 0,
-    .screen_on = NULL,
-};
-
-static int eventct;
-static int epollfd;
-
-#define POWER_SUPPLY_SUBSYSTEM "power_supply"
-
-// epoll_create() parameter is actually unused
-#define MAX_EPOLL_EVENTS 40
-static int uevent_fd;
-static int wakealarm_fd;
-
-// -1 for no epoll timeout
-static int awake_poll_interval = -1;
-
-static int wakealarm_wake_interval = DEFAULT_PERIODIC_CHORES_INTERVAL_FAST;
-
-static BatteryMonitor* gBatteryMonitor;
-
-struct healthd_mode_ops *healthd_mode_ops;
+// main healthd loop
+extern int healthd_main(void);
 
 // Android mode
 
 extern void healthd_mode_android_init(struct healthd_config *config);
 extern int healthd_mode_android_preparetowait(void);
+extern void healthd_mode_android_heartbeat(void);
 extern void healthd_mode_android_battery_update(
     struct android::BatteryProperties *props);
 
-// Charger mode
-
-extern void healthd_mode_charger_init(struct healthd_config *config);
-extern int healthd_mode_charger_preparetowait(void);
-extern void healthd_mode_charger_heartbeat(void);
-extern void healthd_mode_charger_battery_update(
-    struct android::BatteryProperties *props);
-
-// NOPs for modes that need no special action
-
-static void healthd_mode_nop_init(struct healthd_config *config);
-static int healthd_mode_nop_preparetowait(void);
-static void healthd_mode_nop_heartbeat(void);
-static void healthd_mode_nop_battery_update(
-    struct android::BatteryProperties *props);
-
 static struct healthd_mode_ops android_ops = {
     .init = healthd_mode_android_init,
     .preparetowait = healthd_mode_android_preparetowait,
-    .heartbeat = healthd_mode_nop_heartbeat,
+    .heartbeat = healthd_mode_android_heartbeat,
     .battery_update = healthd_mode_android_battery_update,
 };
 
-static struct healthd_mode_ops charger_ops = {
-#ifdef CHARGER_NO_UI
-    .init = healthd_mode_nop_init,
-    .preparetowait = healthd_mode_nop_preparetowait,
-    .heartbeat = healthd_mode_nop_heartbeat,
-    .battery_update = healthd_mode_nop_battery_update,
-#else
-    .init = healthd_mode_charger_init,
-    .preparetowait = healthd_mode_charger_preparetowait,
-    .heartbeat = healthd_mode_charger_heartbeat,
-    .battery_update = healthd_mode_charger_battery_update,
-#endif
-};
-
-static struct healthd_mode_ops recovery_ops = {
-    .init = healthd_mode_nop_init,
-    .preparetowait = healthd_mode_nop_preparetowait,
-    .heartbeat = healthd_mode_nop_heartbeat,
-    .battery_update = healthd_mode_nop_battery_update,
-};
-
-static void healthd_mode_nop_init(struct healthd_config* /*config*/) {
-}
-
-static int healthd_mode_nop_preparetowait(void) {
-    return -1;
-}
-
-static void healthd_mode_nop_heartbeat(void) {
-}
-
-static void healthd_mode_nop_battery_update(
-    struct android::BatteryProperties* /*props*/) {
-}
-
-int healthd_register_event(int fd, void (*handler)(uint32_t), EventWakeup wakeup) {
-    struct epoll_event ev;
-
-    ev.events = EPOLLIN;
-
-    if (wakeup == EVENT_WAKEUP_FD)
-        ev.events |= EPOLLWAKEUP;
-
-    ev.data.ptr = (void *)handler;
-    if (epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev) == -1) {
-        KLOG_ERROR(LOG_TAG,
-                   "epoll_ctl failed; errno=%d\n", errno);
-        return -1;
-    }
-
-    eventct++;
-    return 0;
-}
-
-static void wakealarm_set_interval(int interval) {
-    struct itimerspec itval;
-
-    if (wakealarm_fd == -1)
-            return;
-
-    wakealarm_wake_interval = interval;
-
-    if (interval == -1)
-        interval = 0;
-
-    itval.it_interval.tv_sec = interval;
-    itval.it_interval.tv_nsec = 0;
-    itval.it_value.tv_sec = interval;
-    itval.it_value.tv_nsec = 0;
-
-    if (timerfd_settime(wakealarm_fd, 0, &itval, NULL) == -1)
-        KLOG_ERROR(LOG_TAG, "wakealarm_set_interval: timerfd_settime failed\n");
-}
-
-status_t healthd_get_property(int id, struct BatteryProperty *val) {
-    return gBatteryMonitor->getProperty(id, val);
-}
+int main(int /*argc*/, char ** /*argv*/) {
 
-void healthd_battery_update(void) {
-    // Fast wake interval when on charger (watch for overheat);
-    // slow wake interval when on battery (watch for drained battery).
-
-   int new_wake_interval = gBatteryMonitor->update() ?
-       healthd_config.periodic_chores_interval_fast :
-           healthd_config.periodic_chores_interval_slow;
-
-    if (new_wake_interval != wakealarm_wake_interval)
-            wakealarm_set_interval(new_wake_interval);
-
-    // During awake periods poll at fast rate.  If wake alarm is set at fast
-    // rate then just use the alarm; if wake alarm is set at slow rate then
-    // poll at fast rate while awake and let alarm wake up at slow rate when
-    // asleep.
-
-    if (healthd_config.periodic_chores_interval_fast == -1)
-        awake_poll_interval = -1;
-    else
-        awake_poll_interval =
-            new_wake_interval == healthd_config.periodic_chores_interval_fast ?
-                -1 : healthd_config.periodic_chores_interval_fast * 1000;
-}
-
-void healthd_dump_battery_state(int fd) {
-    gBatteryMonitor->dumpState(fd);
-    fsync(fd);
-}
-
-static void periodic_chores() {
-    healthd_battery_update();
-}
-
-#define UEVENT_MSG_LEN 2048
-static void uevent_event(uint32_t /*epevents*/) {
-    char msg[UEVENT_MSG_LEN+2];
-    char *cp;
-    int n;
-
-    n = uevent_kernel_multicast_recv(uevent_fd, msg, UEVENT_MSG_LEN);
-    if (n <= 0)
-        return;
-    if (n >= UEVENT_MSG_LEN)   /* overflow -- discard */
-        return;
-
-    msg[n] = '\0';
-    msg[n+1] = '\0';
-    cp = msg;
-
-    while (*cp) {
-        if (!strcmp(cp, "SUBSYSTEM=" POWER_SUPPLY_SUBSYSTEM)) {
-            healthd_battery_update();
-            break;
-        }
-
-        /* advance to after the next \0 */
-        while (*cp++)
-            ;
-    }
-}
-
-static void uevent_init(void) {
-    uevent_fd = uevent_open_socket(64*1024, true);
-
-    if (uevent_fd < 0) {
-        KLOG_ERROR(LOG_TAG, "uevent_init: uevent_open_socket failed\n");
-        return;
-    }
-
-    fcntl(uevent_fd, F_SETFL, O_NONBLOCK);
-    if (healthd_register_event(uevent_fd, uevent_event, EVENT_WAKEUP_FD))
-        KLOG_ERROR(LOG_TAG,
-                   "register for uevent events failed\n");
-}
-
-static void wakealarm_event(uint32_t /*epevents*/) {
-    unsigned long long wakeups;
-
-    if (read(wakealarm_fd, &wakeups, sizeof(wakeups)) == -1) {
-        KLOG_ERROR(LOG_TAG, "wakealarm_event: read wakealarm fd failed\n");
-        return;
-    }
-
-    periodic_chores();
-}
-
-static void wakealarm_init(void) {
-    wakealarm_fd = timerfd_create(CLOCK_BOOTTIME_ALARM, TFD_NONBLOCK);
-    if (wakealarm_fd == -1) {
-        KLOG_ERROR(LOG_TAG, "wakealarm_init: timerfd_create failed\n");
-        return;
-    }
-
-    if (healthd_register_event(wakealarm_fd, wakealarm_event, EVENT_WAKEUP_FD))
-        KLOG_ERROR(LOG_TAG,
-                   "Registration of wakealarm event failed\n");
-
-    wakealarm_set_interval(healthd_config.periodic_chores_interval_fast);
-}
-
-static void healthd_mainloop(void) {
-    int nevents = 0;
-    while (1) {
-        struct epoll_event events[eventct];
-        int timeout = awake_poll_interval;
-        int mode_timeout;
-
-        /* Don't wait for first timer timeout to run periodic chores */
-        if (!nevents)
-            periodic_chores();
-
-        healthd_mode_ops->heartbeat();
-
-        mode_timeout = healthd_mode_ops->preparetowait();
-        if (timeout < 0 || (mode_timeout > 0 && mode_timeout < timeout))
-            timeout = mode_timeout;
-        nevents = epoll_wait(epollfd, events, eventct, timeout);
-        if (nevents == -1) {
-            if (errno == EINTR)
-                continue;
-            KLOG_ERROR(LOG_TAG, "healthd_mainloop: epoll_wait failed\n");
-            break;
-        }
-
-        for (int n = 0; n < nevents; ++n) {
-            if (events[n].data.ptr)
-                (*(void (*)(int))events[n].data.ptr)(events[n].events);
-        }
-    }
-
-    return;
-}
-
-static int healthd_init() {
-    epollfd = epoll_create(MAX_EPOLL_EVENTS);
-    if (epollfd == -1) {
-        KLOG_ERROR(LOG_TAG,
-                   "epoll_create failed; errno=%d\n",
-                   errno);
-        return -1;
-    }
-
-    healthd_board_init(&healthd_config);
-    healthd_mode_ops->init(&healthd_config);
-    wakealarm_init();
-    uevent_init();
-    gBatteryMonitor = new BatteryMonitor();
-    gBatteryMonitor->init(&healthd_config);
-    return 0;
-}
-
-int main(int argc, char **argv) {
-    int ch;
-    int ret;
-
-    klog_set_level(KLOG_LEVEL);
     healthd_mode_ops = &android_ops;
 
-    if (!strcmp(basename(argv[0]), "charger")) {
-        healthd_mode_ops = &charger_ops;
-    } else {
-        while ((ch = getopt(argc, argv, "cr")) != -1) {
-            switch (ch) {
-            case 'c':
-                healthd_mode_ops = &charger_ops;
-                break;
-            case 'r':
-                healthd_mode_ops = &recovery_ops;
-                break;
-            case '?':
-            default:
-                KLOG_ERROR(LOG_TAG, "Unrecognized healthd option: %c\n",
-                           optopt);
-                exit(1);
-            }
-        }
-    }
-
-    ret = healthd_init();
-    if (ret) {
-        KLOG_ERROR("Initialization failed, exiting\n");
-        exit(2);
-    }
-
-    healthd_mainloop();
-    KLOG_ERROR("Main loop terminated, exiting\n");
-    return 3;
+    return healthd_main();
 }
diff --git a/healthd/healthd_common.cpp b/healthd/healthd_common.cpp
new file mode 100644
index 000000000..659991918
--- /dev/null
+++ b/healthd/healthd_common.cpp
@@ -0,0 +1,304 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#define LOG_TAG "healthd-common"
+#define KLOG_LEVEL 6
+
+#include <healthd/healthd.h>
+#include <healthd/BatteryMonitor.h>
+
+#include <errno.h>
+#include <libgen.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <batteryservice/BatteryService.h>
+#include <cutils/klog.h>
+#include <cutils/uevent.h>
+#include <sys/epoll.h>
+#include <sys/timerfd.h>
+#include <utils/Errors.h>
+
+using namespace android;
+
+#ifndef BOARD_PERIODIC_CHORES_INTERVAL_FAST
+  // Periodic chores fast interval in seconds
+  #define DEFAULT_PERIODIC_CHORES_INTERVAL_FAST (60 * 1)
+#else
+  #define DEFAULT_PERIODIC_CHORES_INTERVAL_FAST (BOARD_PERIODIC_CHORES_INTERVAL_FAST)
+#endif
+
+#ifndef BOARD_PERIODIC_CHORES_INTERVAL_SLOW
+  // Periodic chores fast interval in seconds
+  #define DEFAULT_PERIODIC_CHORES_INTERVAL_SLOW (60 * 10)
+#else
+  #define DEFAULT_PERIODIC_CHORES_INTERVAL_SLOW (BOARD_PERIODIC_CHORES_INTERVAL_SLOW)
+#endif
+
+static struct healthd_config healthd_config = {
+    .periodic_chores_interval_fast = DEFAULT_PERIODIC_CHORES_INTERVAL_FAST,
+    .periodic_chores_interval_slow = DEFAULT_PERIODIC_CHORES_INTERVAL_SLOW,
+    .batteryStatusPath = String8(String8::kEmptyString),
+    .batteryHealthPath = String8(String8::kEmptyString),
+    .batteryPresentPath = String8(String8::kEmptyString),
+    .batteryCapacityPath = String8(String8::kEmptyString),
+    .batteryVoltagePath = String8(String8::kEmptyString),
+    .batteryTemperaturePath = String8(String8::kEmptyString),
+    .batteryTechnologyPath = String8(String8::kEmptyString),
+    .batteryCurrentNowPath = String8(String8::kEmptyString),
+    .batteryCurrentAvgPath = String8(String8::kEmptyString),
+    .batteryChargeCounterPath = String8(String8::kEmptyString),
+    .batteryFullChargePath = String8(String8::kEmptyString),
+    .batteryCycleCountPath = String8(String8::kEmptyString),
+    .energyCounter = NULL,
+    .boot_min_cap = 0,
+    .screen_on = NULL,
+};
+
+static int eventct;
+static int epollfd;
+
+#define POWER_SUPPLY_SUBSYSTEM "power_supply"
+
+// epoll_create() parameter is actually unused
+#define MAX_EPOLL_EVENTS 40
+static int uevent_fd;
+static int wakealarm_fd;
+
+// -1 for no epoll timeout
+static int awake_poll_interval = -1;
+
+static int wakealarm_wake_interval = DEFAULT_PERIODIC_CHORES_INTERVAL_FAST;
+
+static BatteryMonitor* gBatteryMonitor;
+
+struct healthd_mode_ops *healthd_mode_ops;
+
+int healthd_register_event(int fd, void (*handler)(uint32_t), EventWakeup wakeup) {
+    struct epoll_event ev;
+
+    ev.events = EPOLLIN;
+
+    if (wakeup == EVENT_WAKEUP_FD)
+        ev.events |= EPOLLWAKEUP;
+
+    ev.data.ptr = (void *)handler;
+    if (epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev) == -1) {
+        KLOG_ERROR(LOG_TAG,
+                   "epoll_ctl failed; errno=%d\n", errno);
+        return -1;
+    }
+
+    eventct++;
+    return 0;
+}
+
+static void wakealarm_set_interval(int interval) {
+    struct itimerspec itval;
+
+    if (wakealarm_fd == -1)
+            return;
+
+    wakealarm_wake_interval = interval;
+
+    if (interval == -1)
+        interval = 0;
+
+    itval.it_interval.tv_sec = interval;
+    itval.it_interval.tv_nsec = 0;
+    itval.it_value.tv_sec = interval;
+    itval.it_value.tv_nsec = 0;
+
+    if (timerfd_settime(wakealarm_fd, 0, &itval, NULL) == -1)
+        KLOG_ERROR(LOG_TAG, "wakealarm_set_interval: timerfd_settime failed\n");
+}
+
+status_t healthd_get_property(int id, struct BatteryProperty *val) {
+    return gBatteryMonitor->getProperty(id, val);
+}
+
+void healthd_battery_update(void) {
+    // Fast wake interval when on charger (watch for overheat);
+    // slow wake interval when on battery (watch for drained battery).
+
+   int new_wake_interval = gBatteryMonitor->update() ?
+       healthd_config.periodic_chores_interval_fast :
+           healthd_config.periodic_chores_interval_slow;
+
+    if (new_wake_interval != wakealarm_wake_interval)
+            wakealarm_set_interval(new_wake_interval);
+
+    // During awake periods poll at fast rate.  If wake alarm is set at fast
+    // rate then just use the alarm; if wake alarm is set at slow rate then
+    // poll at fast rate while awake and let alarm wake up at slow rate when
+    // asleep.
+
+    if (healthd_config.periodic_chores_interval_fast == -1)
+        awake_poll_interval = -1;
+    else
+        awake_poll_interval =
+            new_wake_interval == healthd_config.periodic_chores_interval_fast ?
+                -1 : healthd_config.periodic_chores_interval_fast * 1000;
+}
+
+void healthd_dump_battery_state(int fd) {
+    gBatteryMonitor->dumpState(fd);
+    fsync(fd);
+}
+
+static void periodic_chores() {
+    healthd_battery_update();
+}
+
+#define UEVENT_MSG_LEN 2048
+static void uevent_event(uint32_t /*epevents*/) {
+    char msg[UEVENT_MSG_LEN+2];
+    char *cp;
+    int n;
+
+    n = uevent_kernel_multicast_recv(uevent_fd, msg, UEVENT_MSG_LEN);
+    if (n <= 0)
+        return;
+    if (n >= UEVENT_MSG_LEN)   /* overflow -- discard */
+        return;
+
+    msg[n] = '\0';
+    msg[n+1] = '\0';
+    cp = msg;
+
+    while (*cp) {
+        if (!strcmp(cp, "SUBSYSTEM=" POWER_SUPPLY_SUBSYSTEM)) {
+            healthd_battery_update();
+            break;
+        }
+
+        /* advance to after the next \0 */
+        while (*cp++)
+            ;
+    }
+}
+
+static void uevent_init(void) {
+    uevent_fd = uevent_open_socket(64*1024, true);
+
+    if (uevent_fd < 0) {
+        KLOG_ERROR(LOG_TAG, "uevent_init: uevent_open_socket failed\n");
+        return;
+    }
+
+    fcntl(uevent_fd, F_SETFL, O_NONBLOCK);
+    if (healthd_register_event(uevent_fd, uevent_event, EVENT_WAKEUP_FD))
+        KLOG_ERROR(LOG_TAG,
+                   "register for uevent events failed\n");
+}
+
+static void wakealarm_event(uint32_t /*epevents*/) {
+    unsigned long long wakeups;
+
+    if (read(wakealarm_fd, &wakeups, sizeof(wakeups)) == -1) {
+        KLOG_ERROR(LOG_TAG, "wakealarm_event: read wakealarm fd failed\n");
+        return;
+    }
+
+    periodic_chores();
+}
+
+static void wakealarm_init(void) {
+    wakealarm_fd = timerfd_create(CLOCK_BOOTTIME_ALARM, TFD_NONBLOCK);
+    if (wakealarm_fd == -1) {
+        KLOG_ERROR(LOG_TAG, "wakealarm_init: timerfd_create failed\n");
+        return;
+    }
+
+    if (healthd_register_event(wakealarm_fd, wakealarm_event, EVENT_WAKEUP_FD))
+        KLOG_ERROR(LOG_TAG,
+                   "Registration of wakealarm event failed\n");
+
+    wakealarm_set_interval(healthd_config.periodic_chores_interval_fast);
+}
+
+static void healthd_mainloop(void) {
+    int nevents = 0;
+    while (1) {
+        struct epoll_event events[eventct];
+        int timeout = awake_poll_interval;
+        int mode_timeout;
+
+        /* Don't wait for first timer timeout to run periodic chores */
+        if (!nevents)
+            periodic_chores();
+
+        healthd_mode_ops->heartbeat();
+
+        mode_timeout = healthd_mode_ops->preparetowait();
+        if (timeout < 0 || (mode_timeout > 0 && mode_timeout < timeout))
+            timeout = mode_timeout;
+        nevents = epoll_wait(epollfd, events, eventct, timeout);
+        if (nevents == -1) {
+            if (errno == EINTR)
+                continue;
+            KLOG_ERROR(LOG_TAG, "healthd_mainloop: epoll_wait failed\n");
+            break;
+        }
+
+        for (int n = 0; n < nevents; ++n) {
+            if (events[n].data.ptr)
+                (*(void (*)(int))events[n].data.ptr)(events[n].events);
+        }
+    }
+
+    return;
+}
+
+static int healthd_init() {
+    epollfd = epoll_create(MAX_EPOLL_EVENTS);
+    if (epollfd == -1) {
+        KLOG_ERROR(LOG_TAG,
+                   "epoll_create failed; errno=%d\n",
+                   errno);
+        return -1;
+    }
+
+    healthd_board_init(&healthd_config);
+    healthd_mode_ops->init(&healthd_config);
+    wakealarm_init();
+    uevent_init();
+    gBatteryMonitor = new BatteryMonitor();
+    gBatteryMonitor->init(&healthd_config);
+    return 0;
+}
+
+int healthd_main() {
+    int ret;
+
+    klog_set_level(KLOG_LEVEL);
+
+    if (!healthd_mode_ops) {
+        KLOG_ERROR("healthd ops not set, exiting\n");
+        exit(1);
+    }
+
+    ret = healthd_init();
+    if (ret) {
+        KLOG_ERROR("Initialization failed, exiting\n");
+        exit(2);
+    }
+
+    healthd_mainloop();
+    KLOG_ERROR("Main loop terminated, exiting\n");
+    return 3;
+}
diff --git a/healthd/healthd_mode_android.cpp b/healthd/healthd_mode_android.cpp
index 323ef52fd..c6123137a 100644
--- a/healthd/healthd_mode_android.cpp
+++ b/healthd/healthd_mode_android.cpp
@@ -42,6 +42,9 @@ int healthd_mode_android_preparetowait(void) {
     return -1;
 }
 
+void healthd_mode_android_heartbeat(void) {
+}
+
 static void binder_event(uint32_t /*epevents*/) {
     IPCThreadState::self()->handlePolledCommands();
 }