healthd: Add system health monitoring daemon

Initially moving battery health monitoring here.

Command line flag -n tells healthd not to use (or wait for) servicemanager
in this execution, for charger and recovery modes.

Change-Id: I1720594724af0c068497b359f9c6ad65aeaa1519
diff --git a/healthd/healthd.cpp b/healthd/healthd.cpp
new file mode 100644
index 0000000..1d79097
--- /dev/null
+++ b/healthd/healthd.cpp
@@ -0,0 +1,258 @@
+/*
+ * 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"
+#define KLOG_LEVEL 6
+
+#include "BatteryMonitor.h"
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <batteryservice/BatteryService.h>
+#include <binder/IPCThreadState.h>
+#include <binder/ProcessState.h>
+#include <cutils/klog.h>
+#include <cutils/uevent.h>
+#include <sys/epoll.h>
+#include <sys/timerfd.h>
+
+using namespace android;
+
+// Periodic chores intervals in seconds
+#define PERIODIC_CHORES_INTERVAL_FAST (60 * 1)
+#define PERIODIC_CHORES_INTERVAL_SLOW (60 * 10)
+
+#define POWER_SUPPLY_SUBSYSTEM "power_supply"
+
+// epoll events: uevent, wakealarm, binder
+#define MAX_EPOLL_EVENTS 3
+static int uevent_fd;
+static int wakealarm_fd;
+static int binder_fd;
+
+// -1 for no epoll timeout
+static int awake_poll_interval = -1;
+
+static int wakealarm_wake_interval = PERIODIC_CHORES_INTERVAL_FAST;
+
+static BatteryMonitor* gBatteryMonitor;
+
+static bool nosvcmgr;
+
+static void wakealarm_set_interval(int interval) {
+    struct itimerspec itval;
+
+    if (wakealarm_fd == -1)
+            return;
+
+    wakealarm_wake_interval = interval;
+    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");
+}
+
+static void 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() ?
+        PERIODIC_CHORES_INTERVAL_FAST : 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.
+
+    awake_poll_interval =
+        new_wake_interval == PERIODIC_CHORES_INTERVAL_FAST ?
+        -1 : PERIODIC_CHORES_INTERVAL_FAST * 1000;
+}
+
+static void periodic_chores() {
+    battery_update();
+}
+
+static void uevent_init(void) {
+    uevent_fd = uevent_open_socket(64*1024, true);
+
+    if (uevent_fd >= 0)
+        fcntl(uevent_fd, F_SETFL, O_NONBLOCK);
+    else
+        KLOG_ERROR(LOG_TAG, "uevent_init: uevent_open_socket failed\n");
+}
+
+#define UEVENT_MSG_LEN 1024
+static void uevent_event(void) {
+    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)) {
+            battery_update();
+            break;
+        }
+
+        /* advance to after the next \0 */
+        while (*cp++)
+            ;
+    }
+}
+
+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;
+    }
+
+    wakealarm_set_interval(PERIODIC_CHORES_INTERVAL_FAST);
+}
+
+static void wakealarm_event(void) {
+    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 binder_init(void) {
+    ProcessState::self()->setThreadPoolMaxThreadCount(0);
+    IPCThreadState::self()->disableBackgroundScheduling(true);
+    IPCThreadState::self()->setupPolling(&binder_fd);
+}
+
+static void binder_event(void) {
+    IPCThreadState::self()->handlePolledCommands();
+}
+
+static void healthd_mainloop(void) {
+    struct epoll_event ev;
+    int epollfd;
+    int maxevents = 0;
+
+    epollfd = epoll_create(MAX_EPOLL_EVENTS);
+    if (epollfd == -1) {
+        KLOG_ERROR(LOG_TAG,
+                   "healthd_mainloop: epoll_create failed; errno=%d\n",
+                   errno);
+        return;
+    }
+
+    if (uevent_fd >= 0) {
+        ev.events = EPOLLIN | EPOLLWAKEUP;
+        ev.data.ptr = (void *)uevent_event;
+        if (epoll_ctl(epollfd, EPOLL_CTL_ADD, uevent_fd, &ev) == -1)
+            KLOG_ERROR(LOG_TAG,
+                       "healthd_mainloop: epoll_ctl for uevent_fd failed; errno=%d\n",
+                       errno);
+        else
+            maxevents++;
+    }
+
+    if (wakealarm_fd >= 0) {
+        ev.events = EPOLLIN | EPOLLWAKEUP;
+        ev.data.ptr = (void *)wakealarm_event;
+        if (epoll_ctl(epollfd, EPOLL_CTL_ADD, wakealarm_fd, &ev) == -1)
+            KLOG_ERROR(LOG_TAG,
+                       "healthd_mainloop: epoll_ctl for wakealarm_fd failed; errno=%d\n",
+                       errno);
+        else
+            maxevents++;
+   }
+
+    if (binder_fd >= 0) {
+        ev.events = EPOLLIN | EPOLLWAKEUP;
+        ev.data.ptr= (void *)binder_event;
+        if (epoll_ctl(epollfd, EPOLL_CTL_ADD, binder_fd, &ev) == -1)
+            KLOG_ERROR(LOG_TAG,
+                       "healthd_mainloop: epoll_ctl for binder_fd failed; errno=%d\n",
+                       errno);
+        else
+            maxevents++;
+   }
+
+    while (1) {
+        struct epoll_event events[maxevents];
+        int nevents;
+
+        IPCThreadState::self()->flushCommands();
+        nevents = epoll_wait(epollfd, events, maxevents, awake_poll_interval);
+
+        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 (*)())events[n].data.ptr)();
+        }
+    }
+
+    return;
+}
+
+int main(int argc, char **argv) {
+    int ch;
+
+    klog_set_level(KLOG_LEVEL);
+
+    while ((ch = getopt(argc, argv, "n")) != -1) {
+        switch (ch) {
+        case 'n':
+            nosvcmgr = true;
+            break;
+        case '?':
+        default:
+            KLOG_WARNING(LOG_TAG, "Unrecognized healthd option: %c\n", ch);
+        }
+    }
+
+    wakealarm_init();
+    uevent_init();
+    binder_init();
+    gBatteryMonitor = new BatteryMonitor();
+    gBatteryMonitor->init(nosvcmgr);
+
+    healthd_mainloop();
+    return 0;
+}