Merge changes I707ea158,Ic1c489dd,I7484b772 into main

* changes:
  libhealthloop: Use designated initializers
  libhealthloop: Reduce the number of ScheduleBatteryUpdate() calls
  libhealthloop: Terminate KLOG messages with a newline

health/utils/libhealthloop/HealthLoop.cpp

@@ -43,6 +43,8 @@ namespace android {
 namespace hardware {
 namespace health {
 
+static constexpr uint32_t kUeventMsgLen = 2048;
+
 HealthLoop::HealthLoop() {
     InitHealthdConfig(&healthd_config_);
     awake_poll_interval_ = -1;
@@ -61,14 +63,13 @@ int HealthLoop::RegisterEvent(int fd, BoundFunction func, EventWakeup wakeup) {
                                           EventHandler{this, fd, std::move(func)}))
                                   .get();
 
-    struct epoll_event ev;
-
-    ev.events = EPOLLIN;
+    struct epoll_event ev = {
+        .events = EPOLLIN,
+        .data.ptr = reinterpret_cast<void*>(event_handler),
+    };
 
     if (wakeup == EVENT_WAKEUP_FD) ev.events |= EPOLLWAKEUP;
 
-    ev.data.ptr = reinterpret_cast<void*>(event_handler);
-
     if (epoll_ctl(epollfd_, EPOLL_CTL_ADD, fd, &ev) == -1) {
         KLOG_ERROR(LOG_TAG, "epoll_ctl failed; errno=%d\n", errno);
         return -1;
@@ -121,32 +122,39 @@ void HealthLoop::PeriodicChores() {
     ScheduleBatteryUpdate();
 }
 
-#define UEVENT_MSG_LEN 2048
-void HealthLoop::UeventEvent(uint32_t /*epevents*/) {
-    // No need to lock because uevent_fd_ is guaranteed to be initialized.
-
-    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")) {
-            ScheduleBatteryUpdate();
-            break;
+// Returns true if and only if the battery statistics should be updated.
+bool HealthLoop::RecvUevents() {
+    bool update_stats = false;
+    for (;;) {
+        char msg[kUeventMsgLen + 2];
+        int n = uevent_kernel_multicast_recv(uevent_fd_, msg, kUeventMsgLen);
+        if (n <= 0) return update_stats;
+        if (n >= kUeventMsgLen) {
+            // too long -- discard
+            continue;
+        }
+        if (update_stats) {
+            continue;
         }
 
-        /* advance to after the next \0 */
-        while (*cp++)
-            ;
+        msg[n] = '\0';
+        msg[n + 1] = '\0';
+        for (char* cp = msg; *cp;) {
+            if (strcmp(cp, "SUBSYSTEM=power_supply") == 0) {
+                update_stats = true;
+                break;
+            }
+
+            /* advance to after the next \0 */
+            while (*cp++) {
+            }
+        }
+    }
+}
+
+void HealthLoop::UeventEvent(uint32_t /*epevents*/) {
+    if (RecvUevents()) {
+        ScheduleBatteryUpdate();
     }
 }
 
@@ -183,9 +191,9 @@ void HealthLoop::UeventInit(void) {
         std::string error_msg = attach_result.error().message();
         error_msg +=
                 ". This is expected in recovery mode and also for kernel versions before 5.10.";
-        KLOG_WARNING(LOG_TAG, "%s", error_msg.c_str());
+        KLOG_WARNING(LOG_TAG, "%s\n", error_msg.c_str());
     } else {
-        KLOG_INFO(LOG_TAG, "Successfully attached the BPF filter to the uevent socket");
+        KLOG_INFO(LOG_TAG, "Successfully attached the BPF filter to the uevent socket\n");
     }
 
     if (RegisterEvent(uevent_fd_, &HealthLoop::UeventEvent, EVENT_WAKEUP_FD))

health/utils/libhealthloop/include/health/HealthLoop.h

@@ -93,6 +93,7 @@ class HealthLoop {
     void WakeAlarmInit();
     void WakeAlarmEvent(uint32_t);
     void UeventInit();
+    bool RecvUevents();
     void UeventEvent(uint32_t);
     void WakeAlarmSetInterval(int interval);
     void PeriodicChores();