1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
|
/* timerfd.cc: timerfd helper 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. */
#include "winsup.h"
#include "path.h"
#include "fhandler.h"
#include "pinfo.h"
#include "dtable.h"
#include "cygheap.h"
#include "cygerrno.h"
#include <sys/timerfd.h>
#include "timerfd.h"
#define TFD_CANCEL_FLAGS (TFD_TIMER_ABSTIME | TFD_TIMER_CANCEL_ON_SET)
/* Unfortunately MsgWaitForMultipleObjectsEx does not receive WM_TIMECHANGED
messages without a window defined in this process. Create a hidden window
for that purpose. */
void
timerfd_tracker::create_timechange_window ()
{
WNDCLASSW wclass = { 0 };
WCHAR cname[NAME_MAX];
__small_swprintf (cname, L"Cygwin.timerfd.%p", this);
wclass.lpfnWndProc = DefWindowProcW;
wclass.hInstance = user_data->hmodule;
wclass.lpszClassName = cname;
/* This sleep is required on Windows 10 64 bit only, and only when running
under strace. One of the child processes inheriting the timerfd
descriptor will get a STATUS_FLOAT_INEXACT_RESULT exception inside of
msvcrt.dll. While this is completely crazy in itself, it's apparently
some timing problem. It occurs in 4 out of 5 runs under strace only.
The sleep is required before calling RegisterClassW. Moving it before
CreateWindowExW does not work. What the heck? */
if (being_debugged ())
Sleep (1L);
atom = RegisterClassW (&wclass);
if (!atom)
debug_printf ("RegisterClass %E");
else
{
window = CreateWindowExW (0, cname, cname, WS_POPUP, 0, 0, 0, 0,
NULL, NULL, user_data->hmodule, NULL);
if (!window)
debug_printf ("CreateWindowEx %E");
}
}
void
timerfd_tracker::delete_timechange_window ()
{
if (window)
DestroyWindow (window);
if (atom)
UnregisterClassW ((LPWSTR) (uintptr_t) atom, user_data->hmodule);
}
void
timerfd_tracker::handle_timechange_window ()
{
MSG msg;
while (PeekMessageW (&msg, NULL, 0, 0, PM_REMOVE | PM_QS_POSTMESSAGE)
&& msg.message != WM_QUIT)
{
DispatchMessageW (&msg);
if (msg.message == WM_TIMECHANGE
&& get_clockid () == CLOCK_REALTIME
&& (get_flags () & TFD_CANCEL_FLAGS) == TFD_CANCEL_FLAGS
&& enter_critical_section ())
{
/* make sure to handle each WM_TIMECHANGE only once! */
if (msg.time != tc_time ())
{
set_expiration_count (-1LL);
disarm_timer ();
timer_expired ();
set_tc_time (msg.time);
}
leave_critical_section ();
}
}
}
DWORD
timerfd_tracker::thread_func ()
{
/* Outer loop: Is the timer armed? If not, wait for it. */
HANDLE armed[2] = { arm_evt (),
cancel_evt };
create_timechange_window ();
while (1)
{
switch (MsgWaitForMultipleObjectsEx (2, armed, INFINITE, QS_POSTMESSAGE,
MWMO_INPUTAVAILABLE))
{
case WAIT_OBJECT_0:
break;
case WAIT_OBJECT_0 + 1:
goto canceled;
case WAIT_OBJECT_0 + 2:
handle_timechange_window ();
continue;
default:
continue;
}
/* Inner loop: Timer expired? If not, wait for it. */
HANDLE expired[3] = { timer (),
disarm_evt (),
cancel_evt };
while (1)
{
switch (MsgWaitForMultipleObjectsEx (3, expired, INFINITE,
QS_POSTMESSAGE,
MWMO_INPUTAVAILABLE))
{
case WAIT_OBJECT_0:
break;
case WAIT_OBJECT_0 + 1:
goto disarmed;
case WAIT_OBJECT_0 + 2:
goto canceled;
case WAIT_OBJECT_0 + 3:
handle_timechange_window ();
continue;
default:
continue;
}
if (!enter_critical_section ())
continue;
/* Make sure we haven't been abandoned and/or disarmed
in the meantime */
if (expiration_count () == -1LL
|| IsEventSignalled (disarm_evt ()))
{
leave_critical_section ();
goto disarmed;
}
/* One-shot timer? */
if (!get_interval ())
{
/* Set expiration count, disarm timer */
increment_expiration_count (1);
disarm_timer ();
}
else
{
/* Compute expiration count. */
LONG64 now = get_clock_now ();
LONG64 ts = get_exp_ts ();
LONG64 exp_cnt;
/* Make concessions for unexact realtime clock */
if (ts > now)
ts = now - 1;
exp_cnt = (now - ts + get_interval () - 1) / get_interval ();
increment_expiration_count (exp_cnt);
ts += get_interval () * exp_cnt;
/* Set exp_ts to current timestamp. Make sure exp_ts ends up
bigger than "now" and fix expiration count as required */
while (ts <= (now = get_clock_now ()))
{
exp_cnt = (now - ts + get_interval () - 1) / get_interval ();
increment_expiration_count (exp_cnt);
ts += get_interval () * exp_cnt;
}
set_exp_ts (ts);
/* NtSetTimer allows periods of up to 24 days only. If the time
is longer, we set the timer up as one-shot timer for each
interval. Restart timer here with new due time. */
if (get_interval () > INT_MAX * (NS100PERSEC / MSPERSEC))
{
BOOLEAN Resume = (get_clockid () == CLOCK_REALTIME_ALARM
|| get_clockid () == CLOCK_BOOTTIME_ALARM);
LARGE_INTEGER DueTime = { QuadPart: -get_interval () };
NtSetTimer (timer (), &DueTime, NULL, NULL, Resume, 0, NULL);
}
}
/* Arm the expiry object */
timer_expired ();
leave_critical_section ();
}
disarmed:
;
}
canceled:
delete_timechange_window ();
/* automatically return the cygthread to the cygthread pool */
_my_tls._ctinfo->auto_release ();
return 0;
}
static DWORD WINAPI
timerfd_thread (VOID *arg)
{
timerfd_tracker *tt = ((timerfd_tracker *) arg);
return tt->thread_func ();
}
int
timerfd_tracker::create (clockid_t clock_id)
{
int ret;
NTSTATUS status;
OBJECT_ATTRIBUTES attr;
const ACCESS_MASK access = STANDARD_RIGHTS_REQUIRED
| SECTION_MAP_READ | SECTION_MAP_WRITE;
SIZE_T vsize = wincap.page_size ();
LARGE_INTEGER sectionsize = { QuadPart: (LONGLONG) wincap.page_size () };
/* Valid clock? */
if (!get_clock (clock_id))
{
ret = -EINVAL;
goto err;
}
/* Create shared objects */
InitializeObjectAttributes (&attr, NULL, OBJ_INHERIT, NULL, NULL);
/* Create shared section */
status = NtCreateSection (&tfd_shared_hdl, access, &attr, §ionsize,
PAGE_READWRITE, SEC_COMMIT, NULL);
if (!NT_SUCCESS (status))
{
ret = -geterrno_from_nt_status (status);
goto err;
}
/* Create access mutex */
status = NtCreateMutant (&_access_mtx, MUTEX_ALL_ACCESS, &attr, FALSE);
if (!NT_SUCCESS (status))
{
ret = -geterrno_from_nt_status (status);
goto err_close_tfd_shared_hdl;
}
/* Create "timer is armed" event, set to "Unsignaled" at creation time */
status = NtCreateEvent (&_arm_evt, EVENT_ALL_ACCESS, &attr,
NotificationEvent, FALSE);
if (!NT_SUCCESS (status))
{
ret = -geterrno_from_nt_status (status);
goto err_close_access_mtx;
}
/* Create "timer is disarmed" event, set to "Signaled" at creation time */
status = NtCreateEvent (&_disarm_evt, EVENT_ALL_ACCESS, &attr,
NotificationEvent, TRUE);
if (!NT_SUCCESS (status))
{
ret = -geterrno_from_nt_status (status);
goto err_close_arm_evt;
}
/* Create timer */
status = NtCreateTimer (&_timer, TIMER_ALL_ACCESS, &attr,
SynchronizationTimer);
if (!NT_SUCCESS (status))
{
ret = -geterrno_from_nt_status (status);
goto err_close_disarm_evt;
}
/* Create "timer expired" semaphore */
status = NtCreateEvent (&_expired_evt, EVENT_ALL_ACCESS, &attr,
NotificationEvent, FALSE);
if (!NT_SUCCESS (status))
{
ret = -geterrno_from_nt_status (status);
goto err_close_timer;
}
/* Create process-local cancel event for this processes timer thread
(has to be recreated after fork/exec)*/
InitializeObjectAttributes (&attr, NULL, 0, NULL, NULL);
status = NtCreateEvent (&cancel_evt, EVENT_ALL_ACCESS, &attr,
NotificationEvent, FALSE);
if (!NT_SUCCESS (status))
{
ret = -geterrno_from_nt_status (status);
goto err_close_expired_evt;
}
/* Create sync event for this processes timer thread */
status = NtCreateEvent (&sync_thr, EVENT_ALL_ACCESS, &attr,
NotificationEvent, FALSE);
if (!NT_SUCCESS (status))
{
ret = -geterrno_from_nt_status (status);
goto err_close_cancel_evt;
}
/* Create section mapping (has to be recreated after fork/exec) */
tfd_shared = NULL;
status = NtMapViewOfSection (tfd_shared_hdl, NtCurrentProcess (),
(void **) &tfd_shared, 0, vsize, NULL,
&vsize, ViewShare, 0, PAGE_READWRITE);
if (!NT_SUCCESS (status))
{
ret = -geterrno_from_nt_status (status);
goto err_close_sync_thr;
}
/* Initialize clock id */
set_clockid (clock_id);
/* Set our winpid for fixup_after_fork_exec */
winpid = GetCurrentProcessId ();
/* Start timerfd thread */
new cygthread (timerfd_thread, this, "timerfd", sync_thr);
return 0;
err_close_sync_thr:
NtClose (sync_thr);
err_close_cancel_evt:
NtClose (cancel_evt);
err_close_expired_evt:
NtClose (_expired_evt);
err_close_timer:
NtClose (_timer);
err_close_disarm_evt:
NtClose (_disarm_evt);
err_close_arm_evt:
NtClose (_arm_evt);
err_close_access_mtx:
NtClose (_access_mtx);
err_close_tfd_shared_hdl:
NtClose (tfd_shared_hdl);
err:
return ret;
}
/* Return true if this was the last instance of a timerfd, process-wide,
false otherwise. Basically this is a destructor, but one which may
notify the caller NOT to deleted the object. */
bool
timerfd_tracker::dtor ()
{
if (!enter_critical_section ())
return false;
if (decrement_instances () > 0)
{
leave_critical_section ();
return false;
}
if (cancel_evt)
SetEvent (cancel_evt);
if (sync_thr)
{
WaitForSingleObject (sync_thr, INFINITE);
NtClose (sync_thr);
}
leave_critical_section ();
if (tfd_shared)
NtUnmapViewOfSection (NtCurrentProcess (), tfd_shared);
if (cancel_evt)
NtClose (cancel_evt);
NtClose (tfd_shared_hdl);
NtClose (_expired_evt);
NtClose (_timer);
NtClose (_disarm_evt);
NtClose (_arm_evt);
NtClose (_access_mtx);
return true;
}
void
timerfd_tracker::dtor (timerfd_tracker *tfd)
{
if (tfd->dtor ())
cfree (tfd);
}
int
timerfd_tracker::ioctl_set_ticks (uint64_t new_exp_cnt)
{
LONG64 exp_cnt = (LONG64) new_exp_cnt;
if (exp_cnt == 0 || exp_cnt == -1LL)
return -EINVAL;
if (!enter_critical_section ())
return -EBADF;
set_expiration_count (exp_cnt);
timer_expired ();
leave_critical_section ();
return 0;
}
void
timerfd_tracker::init_fixup_after_fork_exec ()
{
/* Run this only if this is the first call, or all previous calls
came from close_on_exec descriptors */
if (winpid == GetCurrentProcessId ())
return;
tfd_shared = NULL;
cancel_evt = NULL;
sync_thr = NULL;
}
void
timerfd_tracker::fixup_after_fork_exec (bool execing)
{
NTSTATUS status;
OBJECT_ATTRIBUTES attr;
SIZE_T vsize = wincap.page_size ();
/* Run this only once per process */
if (winpid == GetCurrentProcessId ())
return;
/* Recreate shared section mapping */
tfd_shared = NULL;
status = NtMapViewOfSection (tfd_shared_hdl, NtCurrentProcess (),
(PVOID *) &tfd_shared, 0, vsize, NULL,
&vsize, ViewShare, 0, PAGE_READWRITE);
if (!NT_SUCCESS (status))
api_fatal ("Can't recreate shared timerfd section during %s, status %y!",
execing ? "execve" : "fork", status);
/* Create cancel event for this processes timer thread */
InitializeObjectAttributes (&attr, NULL, 0, NULL, NULL);
status = NtCreateEvent (&cancel_evt, EVENT_ALL_ACCESS, &attr,
NotificationEvent, FALSE);
if (!NT_SUCCESS (status))
api_fatal ("Can't recreate timerfd cancel event during %s, status %y!",
execing ? "execve" : "fork", status);
/* Create sync event for this processes timer thread */
InitializeObjectAttributes (&attr, NULL, 0, NULL, NULL);
status = NtCreateEvent (&sync_thr, EVENT_ALL_ACCESS, &attr,
NotificationEvent, FALSE);
if (!NT_SUCCESS (status))
api_fatal ("Can't recreate timerfd sync event during %s, status %y!",
execing ? "execve" : "fork", status);
/* Set winpid so we don't run this twice */
winpid = GetCurrentProcessId ();
new cygthread (timerfd_thread, this, "timerfd", sync_thr);
}
LONG64
timerfd_tracker::wait (bool nonblocking)
{
HANDLE w4[2] = { get_timerfd_handle (), NULL };
LONG64 ret;
wait_signal_arrived here (w4[1]);
repeat:
switch (WaitForMultipleObjects (2, w4, FALSE, nonblocking ? 0 : INFINITE))
{
case WAIT_OBJECT_0: /* timer event */
if (!enter_critical_section ())
ret = -EIO;
else
{
ret = read_and_reset_expiration_count ();
leave_critical_section ();
switch (ret)
{
case -1: /* TFD_TIMER_CANCEL_ON_SET */
ret = -ECANCELED;
break;
case 0: /* Another read was quicker. */
if (!nonblocking)
goto repeat;
ret = -EAGAIN;
break;
default: /* Return (positive) expiration count. */
if (ret < 0)
ret = INT64_MAX;
break;
}
}
break;
case WAIT_OBJECT_0 + 1: /* signal */
if (_my_tls.call_signal_handler ())
goto repeat;
ret = -EINTR;
break;
case WAIT_TIMEOUT:
ret = -EAGAIN;
break;
default:
ret = -geterrno_from_win_error ();
break;
}
return ret;
}
int
timerfd_tracker::gettime (struct itimerspec *curr_value)
{
int ret = 0;
__try
{
if (!enter_critical_section ())
{
ret = -EBADF;
__leave;
}
}
__except (NO_ERROR)
{
return -EFAULT;
}
__endtry
__try
{
if (IsEventSignalled (disarm_evt ()))
*curr_value = time_spec ();
else
{
LONG64 next_relative_exp = get_exp_ts () - get_clock_now ();
curr_value->it_value.tv_sec = next_relative_exp / NS100PERSEC;
next_relative_exp -= curr_value->it_value.tv_sec * NS100PERSEC;
curr_value->it_value.tv_nsec = next_relative_exp
* (NSPERSEC / NS100PERSEC);
curr_value->it_interval = time_spec ().it_interval;
}
ret = 0;
}
__except (NO_ERROR)
{
ret = -EFAULT;
}
__endtry
leave_critical_section ();
return ret;
}
int
timerfd_tracker::arm_timer (int flags, const struct itimerspec *new_value)
{
LONG64 interval;
LONG64 ts;
NTSTATUS status;
LARGE_INTEGER DueTime;
BOOLEAN Resume;
LONG Period;
ResetEvent (disarm_evt ());
/* Convert incoming itimerspec into 100ns interval and timestamp */
interval = new_value->it_interval.tv_sec * NS100PERSEC
+ (new_value->it_interval.tv_nsec + (NSPERSEC / NS100PERSEC) - 1)
/ (NSPERSEC / NS100PERSEC);
ts = new_value->it_value.tv_sec * NS100PERSEC
+ (new_value->it_value.tv_nsec + (NSPERSEC / NS100PERSEC) - 1)
/ (NSPERSEC / NS100PERSEC);
set_flags (flags);
if (flags & TFD_TIMER_ABSTIME)
{
if (get_clockid () == CLOCK_REALTIME)
DueTime.QuadPart = ts + FACTOR;
else /* non-REALTIME clocks require relative DueTime. */
{
DueTime.QuadPart = get_clock_now () - ts;
/* If the timestamp was earlier than now, compute number
of expirations and offset DueTime to expire immediately. */
if (DueTime.QuadPart >= 0)
DueTime.QuadPart = -1LL;
}
}
else
{
/* Keep relative timestamps relative for the timer, but store the
expiry timestamp absolute for the timer thread. */
DueTime.QuadPart = -ts;
ts += get_clock_now ();
}
time_spec () = *new_value;
set_exp_ts (ts);
set_interval (interval);
read_and_reset_expiration_count ();
/* Note: Advanced Power Settings -> Sleep -> Allow Wake Timers
since W10 1709 */
Resume = (get_clockid () == CLOCK_REALTIME_ALARM
|| get_clockid () == CLOCK_BOOTTIME_ALARM);
if (interval > INT_MAX * (NS100PERSEC / MSPERSEC))
Period = 0;
else
Period = (interval + (NS100PERSEC / MSPERSEC) - 1)
/ (NS100PERSEC / MSPERSEC);
status = NtSetTimer (timer (), &DueTime, NULL, NULL, Resume, Period, NULL);
if (!NT_SUCCESS (status))
{
disarm_timer ();
return -geterrno_from_nt_status (status);
}
SetEvent (arm_evt ());
return 0;
}
int
timerfd_tracker::settime (int flags, const struct itimerspec *new_value,
struct itimerspec *old_value)
{
int ret = 0;
__try
{
if (!valid_timespec (new_value->it_value)
|| !valid_timespec (new_value->it_interval))
{
ret = -EINVAL;
__leave;
}
if (!enter_critical_section ())
{
ret = -EBADF;
__leave;
}
if (old_value && (ret = gettime (old_value)) < 0)
__leave;
if (new_value->it_value.tv_sec == 0 && new_value->it_value.tv_nsec == 0)
ret = disarm_timer ();
else
ret = arm_timer (flags, new_value);
leave_critical_section ();
ret = 0;
}
__except (NO_ERROR)
{
ret = -EFAULT;
}
__endtry
return ret;
}
|