ANDROID: ag x86: disable wake alarms

On x86 platforms, especially laptops, it might make sense to never
wake device up just to fetch notifications, or perform other tasks
that android would wake device up for

Andorid does not seem to currently use the posix timer_create entry
point, but changing that too for completness, disabling alarms from
userspace

Author: Kethen

fs/timerfd.c

@@ -415,6 +415,15 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
 	BUILD_BUG_ON(TFD_CLOEXEC != O_CLOEXEC);
 	BUILD_BUG_ON(TFD_NONBLOCK != O_NONBLOCK);
 
+	// disabling alarms for android on x86 platforms
+	// doing it in a way that won't cause errors in frameworks/base/apex/jobscheduler/service/jni/com_android_server_alarm_AlarmManagerService.cpp
+	if(clockid == CLOCK_REALTIME_ALARM){
+		clockid = CLOCK_REALTIME;
+	}
+	if(clockid == CLOCK_BOOTTIME_ALARM){
+		clockid = CLOCK_BOOTTIME;
+	}
+
 	if ((flags & ~TFD_CREATE_FLAGS) ||
 	    (clockid != CLOCK_MONOTONIC &&
 	     clockid != CLOCK_REALTIME &&

kernel/time/posix-timers.c

@@ -498,6 +498,12 @@ static int common_timer_create(struct k_itimer *new_timer)
 static int do_timer_create(clockid_t which_clock, struct sigevent *event,
 			   timer_t __user *created_timer_id)
 {
+	if(which_clock == CLOCK_REALTIME_ALARM){
+		which_clock = CLOCK_REALTIME;
+	}
+	if(which_clock == CLOCK_BOOTTIME_ALARM){
+		which_clock = CLOCK_BOOTTIME;
+	}
 	const struct k_clock *kc = clockid_to_kclock(which_clock);
 	struct k_itimer *new_timer;
 	int error, new_timer_id;