newlib-cygwin/winsup/cygwin/timerfd.h

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2019-01-20 02:53:48 +08:00
/* timerfd.h: Define timerfd classes
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#ifndef __TIMERFD_H__
#define __TIMERFD_H__
#include "clock.h"
#include "ntdll.h"
class timerfd_shared
{
HANDLE _access_mtx; /* controls access to shared data */
HANDLE _arm_evt; /* settimer sets event when timer is armed,
unsets event when timer gets disarmed. */
HANDLE _disarm_evt; /* settimer sets event when timer is armed,
unsets event when timer gets disarmed. */
HANDLE _timer; /* SynchronizationTimer */
HANDLE _expired_evt; /* Signal if timer expired, Unsignal on read. */
LONG instance_count; /* each open fd increments this.
If 0 -> delete timerfd_shared */
clockid_t _clockid; /* clockid */
struct itimerspec _time_spec; /* original incoming itimerspec */
LARGE_INTEGER _exp_ts; /* start timestamp or next expire timestamp
in 100ns */
LONG64 _interval; /* timer interval in 100ns */
LONG64 _overrun_count; /* expiry counter */
int _flags; /* settime flags */
int create (clockid_t);
bool dtor ();
/* read access methods */
HANDLE arm_evt () const { return _arm_evt; }
HANDLE disarm_evt () const { return _disarm_evt; }
HANDLE timer () const { return _timer; }
HANDLE expired_evt () const { return _expired_evt; }
LONG64 get_clock_now () const { return get_clock (_clockid)->n100secs (); }
struct itimerspec &time_spec () { return _time_spec; }
int flags () const { return _flags; }
LONG64 overrun_count () const { return _overrun_count; }
void increment_overrun_count (LONG64 add)
{ InterlockedAdd64 (&_overrun_count, add); }
void set_overrun_count (LONG64 newval)
{ InterlockedExchange64 (&_overrun_count, newval); }
LONG64 read_and_reset_overrun_count ()
{
LONG64 ret = InterlockedExchange64 (&_overrun_count, 0);
if (ret)
ResetEvent (_expired_evt);
return ret;
}
/* write access methods */
bool enter_cs ()
{
return WaitForSingleObject (_access_mtx, INFINITE) == WAIT_OBJECT_0;
}
void leave_cs ()
{
ReleaseMutex (_access_mtx);
}
int arm_timer (int, const struct itimerspec *);
int disarm_timer ()
{
ResetEvent (_arm_evt);
memset (&_time_spec, 0, sizeof _time_spec);
_exp_ts.QuadPart = 0;
_interval = 0;
_flags = 0;
NtCancelTimer (timer (), NULL);
SetEvent (_disarm_evt);
return 0;
}
void timer_expired () { SetEvent (_expired_evt); }
void set_exp_ts (LONG64 ts) { _exp_ts.QuadPart = ts; }
friend class timerfd_tracker;
};
class timerfd_tracker /* cygheap! */
{
DWORD winpid; /* This is used @ fork/exec time to know if
this tracker already has been fixed up. */
HANDLE tfd_shared_hdl; /* handle auf shared mem */
timerfd_shared *tfd_shared; /* pointer auf shared mem, needs
NtMapViewOfSection in each new process. */
HANDLE cancel_evt; /* Signal thread to exit. */
HANDLE sync_thr; /* cygthread sync object. */
LONG local_instance_count; /* each open fd increments this.
If 0 -> cancel thread. */
bool dtor ();
bool enter_critical_section () const { return tfd_shared->enter_cs (); }
void leave_critical_section () const { tfd_shared->leave_cs (); }
int arm_timer (int flags, const struct itimerspec *new_value) const
{ return tfd_shared->arm_timer (flags, new_value); }
int disarm_timer () const { return tfd_shared->disarm_timer (); }
void timer_expired () const { tfd_shared->timer_expired (); }
void increment_overrun_count (LONG64 add) const
{ tfd_shared->increment_overrun_count (add); }
void set_overrun_count (uint64_t ov_cnt) const
{ tfd_shared->set_overrun_count ((LONG64) ov_cnt); }
LONG64 read_and_reset_overrun_count () const
{ return tfd_shared->read_and_reset_overrun_count (); }
struct timespec it_value () const
{ return tfd_shared->time_spec ().it_value; }
struct timespec it_interval () const
{ return tfd_shared->time_spec ().it_interval; }
LONG64 get_clock_now () const { return tfd_shared->get_clock_now (); }
LONG64 get_exp_ts () const { return tfd_shared->_exp_ts.QuadPart; }
LONG64 get_interval () const { return tfd_shared->_interval; }
void set_exp_ts (LONG64 ts) const { tfd_shared->set_exp_ts (ts); }
public:
void *operator new (size_t, void *p) __attribute__ ((nothrow)) {return p;}
timerfd_tracker ()
: tfd_shared_hdl (NULL), tfd_shared (NULL), cancel_evt (NULL),
sync_thr (NULL), local_instance_count (1) {}
int create (clockid_t);
int gettime (struct itimerspec *);
int settime (int, const struct itimerspec *, struct itimerspec *);
static void dtor (timerfd_tracker *);
void close ();
void ioctl_set_ticks (uint64_t);
void fixup_after_fork_exec (bool);
void fixup_after_fork () { fixup_after_fork_exec (false); }
void fixup_after_exec () { fixup_after_fork_exec (true); }
HANDLE get_timerfd_handle () const { return tfd_shared->expired_evt (); }
HANDLE get_disarm_evt () const { return tfd_shared->disarm_evt (); }
LONG64 wait (bool);
void increment_global_instances ()
{ InterlockedIncrement (&tfd_shared->instance_count); }
void increment_instances ()
{
InterlockedIncrement (&tfd_shared->instance_count);
InterlockedIncrement (&local_instance_count);
}
void decrement_instances ()
{
InterlockedDecrement (&tfd_shared->instance_count);
InterlockedDecrement (&local_instance_count);
}
DWORD thread_func ();
};
#endif /* __TIMERFD_H__ */