aboutsummaryrefslogtreecommitdiff
path: root/winsup/cygwin/sched.cc
blob: 0f4b2fec7f347eeeb10c8f4072de87a790c999a2 (plain)
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
/* sched.cc: scheduler interface for Cygwin

   Copyright 2001, 2002  Red Hat, Inc.

   Written by Robert Collins <rbtcollins@hotmail.com>

   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. */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#define _WIN32_WINNT 0x300
#include "winsup.h"
#include <limits.h>
#include "cygerrno.h"
#include <assert.h>
#include <stdlib.h>
#include <syslog.h>
#include <sched.h>
#include "pinfo.h"
/* for getpid */
#include <unistd.h>
#include "registry.h"

extern "C" HWND WINAPI GetForegroundWindow();

/* Win32 priority to UNIX priority Mapping.
   For now, I'm just following the spec: any range of priorities is ok.
   There are probably many many issues with this...

   We don't want process's going realtime. Well, they probably could, but the issues
   with avoiding the priority values 17-22 and 27-30 (not supported before win2k)
   make that inefficient.
   However to complicate things most unixes use lower is better priorities.

   So we map -14 to 15, and 15 to 1 via (16- ((n+16) >> 1))
   we then map 1 to 15 to various process class and thread priority combinations

   Then we need to look at the threads vi process priority. As win95 98 and NT 4
   Don't support opening threads cross-process (unless a thread HANDLE is passed around)
   for now, we'll just use the priority class.

   The code and logic are present to calculate the priority for thread
   , if a thread handle can be obtained. Alternatively, if the symbols wouldn't be
   resolved until they are used
   we could support this on windows 2000 and ME now, and just fall back to the
   class only on pre win2000 machines.

   Lastly, because we can't assume that the pid we're given are Windows pids, we can't
   alter non-cygwin started programs.
*/

extern "C"
{

/* max priority for policy */
int
sched_get_priority_max (int policy)
{
  if (policy < 1 || policy > 3)
    {
      set_errno (EINVAL);
      return -1;
    }
  return -14;
}

/* min priority for policy */
int
sched_get_priority_min (int policy)
{
  if (policy < 1 || policy > 3)
    {
      set_errno (EINVAL);
      return -1;
    }
  return 15;
}

/* Check a scheduler parameter struct for valid settings */
int
valid_sched_parameters (const struct sched_param *param)
{
  if (param->sched_priority < -14 || param->sched_priority > 15)
    {
      return 0;
    }
  return -1;

}

/* get sched params for process

   Note, I'm never returning EPERM,
   Always ESRCH. This is by design (If cygwin ever looks at paranoid security
   Walking the pid values is a known hole in some os's)
*/
int
sched_getparam (pid_t pid, struct sched_param *param)
{
  pid_t localpid;
  int winpri;
  if (!param || pid < 0)
    {
      set_errno (EINVAL);
      return -1;
    }

  localpid = pid ? pid : getpid ();

  DWORD Class;
  int ThreadPriority;
  HANDLE process;
  pinfo p (localpid);

  /* get the class */

  if (!p)
    {
      set_errno (ESRCH);
      return -1;
    }
  process = OpenProcess (PROCESS_QUERY_INFORMATION, FALSE, p->dwProcessId);
  if (!process)
    {
      set_errno (ESRCH);
      return -1;
    }
  Class = GetPriorityClass (process);
  CloseHandle (process);
  if (!Class)
    {
      set_errno (ESRCH);
      return -1;
    }
  ThreadPriority = THREAD_PRIORITY_NORMAL;

  /* calculate the unix priority.

     FIXME: windows 2000 supports ABOVE_NORMAL and BELOW_NORMAL class's
     So this logic just defaults those class factors to NORMAL in the calculations */

  switch (Class)
    {
    case IDLE_PRIORITY_CLASS:
      switch (ThreadPriority)
	{
	case THREAD_PRIORITY_IDLE:
	  winpri = 1;
	  break;
	case THREAD_PRIORITY_LOWEST:
	  winpri = 2;
	  break;
	case THREAD_PRIORITY_BELOW_NORMAL:
	  winpri = 3;
	  break;
	case THREAD_PRIORITY_NORMAL:
	  winpri = 4;
	  break;
	case THREAD_PRIORITY_ABOVE_NORMAL:
	  winpri = 5;
	  break;
	case THREAD_PRIORITY_HIGHEST:
	default:
	  winpri = 6;
	  break;
	}
      break;
    case HIGH_PRIORITY_CLASS:
      switch (ThreadPriority)
	{
	case THREAD_PRIORITY_IDLE:
	  winpri = 1;
	  break;
	case THREAD_PRIORITY_LOWEST:
	  winpri = 11;
	  break;
	case THREAD_PRIORITY_BELOW_NORMAL:
	  winpri = 12;
	  break;
	case THREAD_PRIORITY_NORMAL:
	  winpri = 13;
	  break;
	case THREAD_PRIORITY_ABOVE_NORMAL:
	  winpri = 14;
	  break;
	case THREAD_PRIORITY_HIGHEST:
	default:
	  winpri = 15;
	  break;
	}
      break;
    case NORMAL_PRIORITY_CLASS:
    default:
      switch (ThreadPriority)
	{
	case THREAD_PRIORITY_IDLE:
	  winpri = 1;
	  break;
	case THREAD_PRIORITY_LOWEST:
	  winpri = 7;
	  break;
	case THREAD_PRIORITY_BELOW_NORMAL:
	  winpri = 8;
	  break;
	case THREAD_PRIORITY_NORMAL:
	  winpri = 9;
	  break;
	case THREAD_PRIORITY_ABOVE_NORMAL:
	  winpri = 10;
	  break;
	case THREAD_PRIORITY_HIGHEST:
	default:
	  winpri = 11;
	  break;
	}
      break;
    }

  /* reverse out winpri = (16- ((unixpri+16) >> 1)) */
  /*
     winpri-16 = -  (unixpri +16 ) >> 1

     -(winpri-16) = unixpri +16 >> 1
     (-(winpri-16)) << 1 = unixpri+16
     ((-(winpri - 16)) << 1) - 16 = unixpri
   */

  param->sched_priority = ((-(winpri - 16)) << 1) - 16;

  return 0;
}

/* get the scheduler for pid

   All process's on WIN32 run with SCHED_FIFO.
   So we just give an answer.
   (WIN32 uses a multi queue FIFO).
*/
int
sched_getscheduler (pid_t pid)
{
  if (pid < 0)
    return ESRCH;
  else
    return SCHED_FIFO;
}

/* get the time quantum for pid

   Implemented only for NT systems, it fails and sets errno to ESRCH
   for non-NT systems.
*/
int
sched_rr_get_interval (pid_t pid, struct timespec *interval)
{
  static const char quantable[2][2][3] =
    {{{12, 24, 36}, { 6, 12, 18}},
     {{36, 36, 36}, {18, 18, 18}}};
  /* FIXME: Clocktickinterval can be 15 ms for multi-processor system. */
  static const int clocktickinterval = 10;
  static const int quantapertick = 3;

  HWND forwin;
  DWORD forprocid;
  int vfindex, slindex, qindex, prisep;
  long nsec;

  if (!wincap.is_winnt ())
    {
      set_errno (ESRCH);
      return -1;
    }

  forwin = GetForegroundWindow ();
  if (!forwin)
    GetWindowThreadProcessId (forwin, &forprocid);
  else
    forprocid = 0;

  reg_key reg (HKEY_LOCAL_MACHINE, KEY_READ, "SYSTEM", "CurrentControlSet",
	       "Control", "PriorityControl", NULL);
  if (reg.error ())
    {
      set_errno (ESRCH);
      return -1;
    }
  prisep = reg.get_int ("Win32PrioritySeparation", 2);
  pinfo pi (pid ? pid : myself->pid);
  if (!pi)
    {
      set_errno (ESRCH);
      return -1;
    }

  if (pi->dwProcessId == forprocid)
    {
      qindex = prisep & 3;
      qindex = qindex == 3 ? 2 : qindex;
    }
  else
    qindex = 0;
  vfindex = ((prisep >> 2) & 3) % 3;
  if (vfindex == 0)
    vfindex = wincap.is_server () || prisep & 3 == 0 ? 1 : 0;
  else
    vfindex -= 1;
  slindex = ((prisep >> 4) & 3) % 3;
  if (slindex == 0)
    slindex = wincap.is_server () ? 1 : 0;
  else
    slindex -= 1;

  nsec = quantable[vfindex][slindex][qindex] / quantapertick
    * clocktickinterval * 1000000;
  interval->tv_sec = nsec / 1000000000;
  interval->tv_nsec = nsec % 1000000000;

  return 0;
}

/* set the scheduling parameters */
int
sched_setparam (pid_t pid, const struct sched_param *param)
{
  pid_t localpid;
  int winpri;
  DWORD Class;
  int ThreadPriority;
  HANDLE process;

  if (!param || pid < 0)
    {
      set_errno (EINVAL);
      return -1;
    }

  if (!valid_sched_parameters (param))
    {
      set_errno (EINVAL);
      return -1;
    }

  /*  winpri = (16- ((unixpri+16) >> 1)) */
  winpri = 16 - ((param->sched_priority + 16) >> 1);

  /* calculate our desired priority class and thread priority */

  if (winpri < 7)
    Class = IDLE_PRIORITY_CLASS;
  else if (winpri > 10)
    Class = HIGH_PRIORITY_CLASS;
  else
    Class = NORMAL_PRIORITY_CLASS;

  switch (Class)
    {
    case IDLE_PRIORITY_CLASS:
      switch (winpri)
	{
	case 1:
	  ThreadPriority = THREAD_PRIORITY_IDLE;
	  break;
	case 2:
	  ThreadPriority = THREAD_PRIORITY_LOWEST;
	  break;
	case 3:
	  ThreadPriority = THREAD_PRIORITY_BELOW_NORMAL;
	  break;
	case 4:
	  ThreadPriority = THREAD_PRIORITY_NORMAL;
	  break;
	case 5:
	  ThreadPriority = THREAD_PRIORITY_ABOVE_NORMAL;
	  break;
	case 6:
	  ThreadPriority = THREAD_PRIORITY_HIGHEST;
	  break;
	}
      break;
    case NORMAL_PRIORITY_CLASS:
      switch (winpri)
	{
	case 7:
	  ThreadPriority = THREAD_PRIORITY_LOWEST;
	  break;
	case 8:
	  ThreadPriority = THREAD_PRIORITY_BELOW_NORMAL;
	  break;
	case 9:
	  ThreadPriority = THREAD_PRIORITY_NORMAL;
	  break;
	case 10:
	  ThreadPriority = THREAD_PRIORITY_ABOVE_NORMAL;
	  break;
	case 11:
	  ThreadPriority = THREAD_PRIORITY_HIGHEST;
	  break;
	}
      break;
    case HIGH_PRIORITY_CLASS:
      switch (winpri)
	{
	case 12:
	  ThreadPriority = THREAD_PRIORITY_BELOW_NORMAL;
	  break;
	case 13:
	  ThreadPriority = THREAD_PRIORITY_NORMAL;
	  break;
	case 14:
	  ThreadPriority = THREAD_PRIORITY_ABOVE_NORMAL;
	  break;
	case 15:
	  ThreadPriority = THREAD_PRIORITY_HIGHEST;
	  break;
	}
      break;
    }

  localpid = pid ? pid : getpid ();

  pinfo p (localpid);

  /* set the class */

  if (!p)
    {
      set_errno (1);		//ESRCH);
      return -1;
    }
  process =
    OpenProcess (PROCESS_SET_INFORMATION, FALSE, (DWORD) p->dwProcessId);
  if (!process)
    {
      set_errno (2);		//ESRCH);
      return -1;
    }
  if (!SetPriorityClass (process, Class))
    {
      CloseHandle (process);
      set_errno (EPERM);
      return -1;
    }
  CloseHandle (process);

  return 0;
}

/* we map -14 to 15, and 15 to 1 via (16- ((n+16) >> 1)). This lines up with the allowed
 * valueswe return elsewhere in the sched* functions. We then map in groups of three to
 * allowed thread priority's. The reason for dropping accuracy while still returning
 * a wide range of values is to allow more flexible code in the future.
 */
int
sched_set_thread_priority (HANDLE thread, int priority)
{
  int real_pri;
  real_pri = 16 - ((priority + 16) >> 1);
  if (real_pri <1 || real_pri > 15)
    return EINVAL;

  if (real_pri < 4)
    real_pri = THREAD_PRIORITY_LOWEST;
  else if (real_pri < 7)
    real_pri = THREAD_PRIORITY_BELOW_NORMAL;
  else if (real_pri < 10)
    real_pri = THREAD_PRIORITY_NORMAL;
  else if (real_pri < 13)
    real_pri = THREAD_PRIORITY_ABOVE_NORMAL;
  else
    real_pri = THREAD_PRIORITY_HIGHEST;

  if (!SetThreadPriority (thread, real_pri))
    /* invalid handle, no access are the only expected errors. */
    return EPERM;
  return 0;
}

/* set the scheduler */
int
sched_setscheduler (pid_t pid, int policy,
		    const struct sched_param *param)
{
  /* on win32, you can't change the scheduler. Doh! */
  set_errno (ENOSYS);
  return -1;
}

/* yield the cpu */
int
sched_yield (void)
{
  low_priority_sleep (0);
  return 0;
}
}