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
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
|
/*
* Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id$
*
*/
#include <errno.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <setjmp.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/syscall.h>
#include <fcntl.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
/* Static variables: */
static sigset_t sig_to_block = 0xffffffff;
static sigset_t sig_to_unblock = 0;
/* Static function prototype definitions: */
static void
_thread_kern_select(int wait_reqd);
static void
_thread_signal(pthread_t pthread, int sig);
void
_thread_kern_sched(struct sigcontext * scp)
{
#ifndef __alpha
char *fdata;
#endif
int i;
int prio = -1;
pthread_t pthread;
pthread_t pthread_h = NULL;
pthread_t pthread_nxt = NULL;
pthread_t pthread_prv = NULL;
pthread_t pthread_s = NULL;
struct itimerval itimer;
struct timespec ts;
struct timespec ts1;
struct timeval tv;
struct timeval tv1;
/* Block signals: */
_thread_kern_sig_block(NULL);
/* Check if this function was called from the signal handler: */
if (scp != NULL) {
/*
* Copy the signal context to the current thread's jump
* buffer:
*/
memcpy(&_thread_run->saved_sigcontext, scp, sizeof(_thread_run->saved_sigcontext));
#ifndef __alpha
/* Point to the floating point data in the running thread: */
fdata = _thread_run->saved_fp;
/* Save the floating point data: */
__asm__("fnsave %0": :"m"(*fdata));
#endif
/* Flag the signal context as the last state saved: */
_thread_run->sig_saved = 1;
}
/* Save the state of the current thread: */
else if (_thread_sys_setjmp(_thread_run->saved_jmp_buf) != 0) {
/* Unblock signals (just in case): */
_thread_kern_sig_unblock(0);
/*
* This point is reached when a longjmp() is called to
* restore the state of a thread.
*/
return;
} else {
/* Flag the jump buffer was the last state saved: */
_thread_run->sig_saved = 0;
}
/* Point to the first dead thread (if there are any): */
pthread = _thread_dead;
/* There is no previous dead thread: */
pthread_prv = NULL;
/* Enter a loop to cleanup after dead threads: */
while (pthread != NULL) {
/* Save a pointer to the next thread: */
pthread_nxt = pthread->nxt;
/* Check if this thread is one which is running: */
if (pthread == _thread_run || pthread == _thread_initial) {
/*
* Don't destroy the running thread or the initial
* thread.
*/
pthread_prv = pthread;
}
/*
* Check if this thread has detached or if it is a signal
* handler thread:
*/
else if (((pthread->attr.flags & PTHREAD_DETACHED) != 0) || pthread->parent_thread != NULL) {
/* Check if there is no previous dead thread: */
if (pthread_prv == NULL) {
/*
* The dead thread is at the head of the
* list:
*/
_thread_dead = pthread_nxt;
} else {
/*
* The dead thread is not at the head of the
* list:
*/
pthread_prv->nxt = pthread->nxt;
}
/*
* Check if the stack was not specified by the caller
* to pthread_create and has not been destroyed yet:
*/
if (pthread->attr.stackaddr_attr == NULL && pthread->stack != NULL) {
/* Free the stack of the dead thread: */
free(pthread->stack);
}
/* Free the memory allocated to the thread structure: */
free(pthread);
} else {
/*
* This thread has not detached, so do not destroy
* it:
*/
pthread_prv = pthread;
/*
* Check if the stack was not specified by the caller
* to pthread_create and has not been destroyed yet:
*/
if (pthread->attr.stackaddr_attr == NULL && pthread->stack != NULL) {
/* Free the stack of the dead thread: */
free(pthread->stack);
/*
* NULL the stack pointer now that the memory
* has been freed:
*/
pthread->stack = NULL;
}
}
/* Point to the next thread: */
pthread = pthread_nxt;
}
/*
* Enter a the scheduling loop that finds the next thread that is
* ready to run. This loop completes when there are no more threads
* in the global list or when a thread has its state restored by
* either a sigreturn (if the state was saved as a sigcontext) or a
* longjmp (if the state was saved by a setjmp).
*/
while (_thread_link_list != NULL) {
/* Get the current time of day: */
gettimeofday(&tv, NULL);
TIMEVAL_TO_TIMESPEC(&tv, &ts);
/*
* Poll file descriptors to update the state of threads
* waiting on file I/O where data may be available:
*/
_thread_kern_select(0);
/*
* Enter a loop to look for sleeping threads that are ready
* or threads with pending signals that are no longer
* blocked:
*/
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
/* Enter a loop to process the sending signals: */
for (i = 1; i < NSIG; i++) {
/*
* Check if there are no pending signals of
* this type:
*/
if (pthread->sigpend[i] == 0) {
}
/* Check if this signal type is not masked: */
else if (sigismember(&pthread->sigmask, i) == 0) {
/*
* Delete the signal from the set of
* pending signals for this thread:
*/
pthread->sigpend[i] -= 1;
/*
* Act on the signal for the current
* thread:
*/
_thread_signal(pthread, i);
} else {
/*
* This signal is masked, so make
* sure the count does not exceed 1:
*/
pthread->sigpend[i] = 1;
}
}
/* Check if this thread is to timeout: */
if (pthread->state == PS_COND_WAIT ||
pthread->state == PS_SLEEP_WAIT ||
pthread->state == PS_FDR_WAIT ||
pthread->state == PS_FDW_WAIT ||
pthread->state == PS_SELECT_WAIT) {
/* Check if this thread is to wait forever: */
if (pthread->wakeup_time.tv_sec == -1) {
}
/*
* Check if this thread is to wakeup
* immediately or if it is past its wakeup
* time:
*/
else if ((pthread->wakeup_time.tv_sec == 0 &&
pthread->wakeup_time.tv_nsec == 0) ||
(ts.tv_sec > pthread->wakeup_time.tv_sec) ||
((ts.tv_sec == pthread->wakeup_time.tv_sec) &&
(ts.tv_nsec >= pthread->wakeup_time.tv_nsec))) {
/*
* Check if this thread is waiting on
* select:
*/
if (pthread->state == PS_SELECT_WAIT) {
/*
* The select has timed out,
* so zero the file
* descriptor sets:
*/
FD_ZERO(&pthread->data.select_data->readfds);
FD_ZERO(&pthread->data.select_data->writefds);
FD_ZERO(&pthread->data.select_data->exceptfds);
pthread->data.select_data->nfds = 0;
}
/*
* Return an error as an interrupted
* wait:
*/
_thread_seterrno(pthread, EINTR);
/*
* Flag the timeout in the thread
* structure:
*/
pthread->timeout = 1;
/*
* Change the threads state to allow
* it to be restarted:
*/
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
}
}
}
/* Check if there is a current thread: */
if (_thread_run != &_thread_kern_thread) {
/*
* Save the current time as the time that the thread
* became inactive:
*/
_thread_run->last_inactive.tv_sec = tv.tv_sec;
_thread_run->last_inactive.tv_usec = tv.tv_usec;
/*
* Accumulate the number of microseconds that this
* thread has run for:
*/
_thread_run->slice_usec += (_thread_run->last_inactive.tv_sec -
_thread_run->last_active.tv_sec) * 1000000 +
_thread_run->last_inactive.tv_usec -
_thread_run->last_active.tv_usec;
/*
* Check if this thread has reached its allocated
* time slice period:
*/
if (_thread_run->slice_usec > TIMESLICE_USEC) {
/*
* Flag the allocated time slice period as
* up:
*/
_thread_run->slice_usec = -1;
}
}
/* Check if an incremental priority update is required: */
if (((tv.tv_sec - kern_inc_prio_time.tv_sec) * 1000000 +
tv.tv_usec - kern_inc_prio_time.tv_usec) > INC_PRIO_USEC) {
/*
* Enter a loop to look for run-enabled threads that
* have not run since the last time that an
* incremental priority update was performed:
*/
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
/* Check if this thread is unable to run: */
if (pthread->state != PS_RUNNING) {
}
/*
* Check if the last time that this thread
* was run (as indicated by the last time it
* became inactive) is before the time that
* the last incremental priority check was
* made:
*/
else if (timercmp(&_thread_run->last_inactive, &kern_inc_prio_time, >)) {
/*
* Increment the incremental priority
* for this thread in the hope that
* it will eventually get a chance to
* run:
*/
(pthread->inc_prio)++;
}
}
/* Save the new incremental priority update time: */
kern_inc_prio_time.tv_sec = tv.tv_sec;
kern_inc_prio_time.tv_usec = tv.tv_usec;
}
/*
* Enter a loop to look for the first thread of the highest
* priority that is ready to run:
*/
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
/* Check if in single-threaded mode: */
if (_thread_single != NULL) {
/*
* Check if the current thread is
* the thread for which single-threaded
* mode is enabled:
*/
if (pthread == _thread_single) {
/*
* This thread is allowed
* to run.
*/
} else {
/*
* Walk up the signal handler
* parent thread tree to see
* if the current thread is
* descended from the thread
* for which single-threaded
* mode is enabled.
*/
pthread_nxt = pthread;
while(pthread_nxt != NULL &&
pthread_nxt != _thread_single) {
pthread_nxt = pthread->parent_thread;
}
/*
* Check if the current
* thread is not descended
* from the thread for which
* single-threaded mode is
* enabled.
*/
if (pthread_nxt == NULL)
/* Ignore this thread. */
continue;
}
}
/* Check if the current thread is unable to run: */
if (pthread->state != PS_RUNNING) {
}
/*
* Check if no run-enabled thread has been seen or if
* the current thread has a priority higher than the
* highest seen so far:
*/
else if (pthread_h == NULL || (pthread->pthread_priority + pthread->inc_prio) > prio) {
/*
* Save this thread as the highest priority
* thread seen so far:
*/
pthread_h = pthread;
prio = pthread->pthread_priority + pthread->inc_prio;
}
}
/*
* Enter a loop to look for a thread that: 1. Is run-enabled.
* 2. Has the required agregate priority. 3. Has not been
* allocated its allocated time slice. 4. Became inactive
* least recently.
*/
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
/* Check if in single-threaded mode: */
if (_thread_single != NULL) {
/*
* Check if the current thread is
* the thread for which single-threaded
* mode is enabled:
*/
if (pthread == _thread_single) {
/*
* This thread is allowed
* to run.
*/
} else {
/*
* Walk up the signal handler
* parent thread tree to see
* if the current thread is
* descended from the thread
* for which single-threaded
* mode is enabled.
*/
pthread_nxt = pthread;
while(pthread_nxt != NULL &&
pthread_nxt != _thread_single) {
pthread_nxt = pthread->parent_thread;
}
/*
* Check if the current
* thread is not descended
* from the thread for which
* single-threaded mode is
* enabled.
*/
if (pthread_nxt == NULL)
/* Ignore this thread. */
continue;
}
}
/* Check if the current thread is unable to run: */
if (pthread->state != PS_RUNNING) {
/* Ignore threads that are not ready to run. */
}
/*
* Check if the current thread as an agregate
* priority not equal to the highest priority found
* above:
*/
else if ((pthread->pthread_priority + pthread->inc_prio) != prio) {
/*
* Ignore threads which have lower agregate
* priority.
*/
}
/*
* Check if the current thread reached its time slice
* allocation last time it ran (or if it has not run
* yet):
*/
else if (pthread->slice_usec == -1) {
}
/*
* Check if an eligible thread has not been found
* yet, or if the current thread has an inactive time
* earlier than the last one seen:
*/
else if (pthread_s == NULL || timercmp(&pthread->last_inactive, &tv1, <)) {
/*
* Save the pointer to the current thread as
* the most eligible thread seen so far:
*/
pthread_s = pthread;
/*
* Save the time that the selected thread
* became inactive:
*/
tv1.tv_sec = pthread->last_inactive.tv_sec;
tv1.tv_usec = pthread->last_inactive.tv_usec;
}
}
/*
* Check if no thread was selected according to incomplete
* time slice allocation:
*/
if (pthread_s == NULL) {
/*
* Enter a loop to look for any other thread that: 1.
* Is run-enabled. 2. Has the required agregate
* priority. 3. Became inactive least recently.
*/
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
/* Check if in single-threaded mode: */
if (_thread_single != NULL) {
/*
* Check if the current thread is
* the thread for which single-threaded
* mode is enabled:
*/
if (pthread == _thread_single) {
/*
* This thread is allowed
* to run.
*/
} else {
/*
* Walk up the signal handler
* parent thread tree to see
* if the current thread is
* descended from the thread
* for which single-threaded
* mode is enabled.
*/
pthread_nxt = pthread;
while(pthread_nxt != NULL &&
pthread_nxt != _thread_single) {
pthread_nxt = pthread->parent_thread;
}
/*
* Check if the current
* thread is not descended
* from the thread for which
* single-threaded mode is
* enabled.
*/
if (pthread_nxt == NULL)
/* Ignore this thread. */
continue;
}
}
/*
* Check if the current thread is unable to
* run:
*/
if (pthread->state != PS_RUNNING) {
/*
* Ignore threads that are not ready
* to run.
*/
}
/*
* Check if the current thread as an agregate
* priority not equal to the highest priority
* found above:
*/
else if ((pthread->pthread_priority + pthread->inc_prio) != prio) {
/*
* Ignore threads which have lower
* agregate priority.
*/
}
/*
* Check if an eligible thread has not been
* found yet, or if the current thread has an
* inactive time earlier than the last one
* seen:
*/
else if (pthread_s == NULL || timercmp(&pthread->last_inactive, &tv1, <)) {
/*
* Save the pointer to the current
* thread as the most eligible thread
* seen so far:
*/
pthread_s = pthread;
/*
* Save the time that the selected
* thread became inactive:
*/
tv1.tv_sec = pthread->last_inactive.tv_sec;
tv1.tv_usec = pthread->last_inactive.tv_usec;
}
}
}
/* Check if there are no threads ready to run: */
if (pthread_s == NULL) {
/*
* Lock the pthread kernel by changing the pointer to
* the running thread to point to the global kernel
* thread structure:
*/
_thread_run = &_thread_kern_thread;
/*
* There are no threads ready to run, so wait until
* something happens that changes this condition:
*/
_thread_kern_select(1);
} else {
/* Make the selected thread the current thread: */
_thread_run = pthread_s;
/*
* Save the current time as the time that the thread
* became active:
*/
_thread_run->last_active.tv_sec = tv.tv_sec;
_thread_run->last_active.tv_usec = tv.tv_usec;
/*
* Check if this thread is running for the first time
* or running again after using its full time slice
* allocation:
*/
if (_thread_run->slice_usec == -1) {
/* Reset the accumulated time slice period: */
_thread_run->slice_usec = 0;
}
/*
* Reset the incremental priority now that this
* thread has been given the chance to run:
*/
_thread_run->inc_prio = 0;
/* Check if there is more than one thread: */
if (_thread_run != _thread_link_list || _thread_run->nxt != NULL) {
/*
* Define the maximum time before a SIGVTALRM
* is required:
*/
itimer.it_value.tv_sec = 0;
itimer.it_value.tv_usec = TIMESLICE_USEC;
/*
* The interval timer is not reloaded when it
* times out. The interval time needs to be
* calculated every time.
*/
itimer.it_interval.tv_sec = 0;
itimer.it_interval.tv_usec = 0;
/*
* Enter a loop to look for threads waiting
* for a time:
*/
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
/*
* Check if this thread is to
* timeout:
*/
if (pthread->state == PS_COND_WAIT ||
pthread->state == PS_SLEEP_WAIT ||
pthread->state == PS_FDR_WAIT ||
pthread->state == PS_FDW_WAIT ||
pthread->state == PS_SELECT_WAIT) {
/*
* Check if this thread is to
* wait forever:
*/
if (pthread->wakeup_time.tv_sec == -1) {
}
/*
* Check if this thread is to
* wakeup immediately:
*/
else if (pthread->wakeup_time.tv_sec == 0 &&
pthread->wakeup_time.tv_nsec == 0) {
}
/*
* Check if the current time
* is after the wakeup time:
*/
else if ((ts.tv_sec > pthread->wakeup_time.tv_sec) ||
((ts.tv_sec == pthread->wakeup_time.tv_sec) &&
(ts.tv_nsec > pthread->wakeup_time.tv_nsec))) {
} else {
/*
* Calculate the time
* until this thread
* is ready, allowing
* for the clock
* resolution:
*/
ts1.tv_sec = pthread->wakeup_time.tv_sec - ts.tv_sec;
ts1.tv_nsec = pthread->wakeup_time.tv_nsec - ts.tv_nsec +
CLOCK_RES_NSEC;
/*
* Check for
* underflow of the
* nanosecond field:
*/
if (ts1.tv_nsec < 0) {
/*
* Allow for
* the
* underflow
* of the
* nanosecond
* field:
*/
ts1.tv_sec--;
ts1.tv_nsec += 1000000000;
}
/*
* Check for overflow
* of the nanosecond
* field:
*/
if (ts1.tv_nsec >= 1000000000) {
/*
* Allow for
* the
* overflow
* of the
* nanosecond
* field:
*/
ts1.tv_sec++;
ts1.tv_nsec -= 1000000000;
}
/*
* Convert the
* timespec structure
* to a timeval
* structure:
*/
TIMESPEC_TO_TIMEVAL(&tv, &ts1);
/*
* Check if the
* thread will be
* ready sooner than
* the earliest one
* found so far:
*/
if (timercmp(&tv, &itimer.it_value, <)) {
/*
* Update the
* time
* value:
*/
itimer.it_value.tv_sec = tv.tv_sec;
itimer.it_value.tv_usec = tv.tv_usec;
}
}
}
}
/*
* Start the interval timer for the
* calculated time interval:
*/
if (setitimer(ITIMER_VIRTUAL, &itimer, NULL) != 0) {
/*
* Cannot initialise the timer, so
* abort this process:
*/
PANIC("Cannot set virtual timer");
}
}
/* Check if a signal context was saved: */
if (_thread_run->sig_saved == 1) {
#ifndef __alpha
/*
* Point to the floating point data in the
* running thread:
*/
fdata = _thread_run->saved_fp;
/* Restore the floating point state: */
__asm__("frstor %0": :"m"(*fdata));
#endif
/*
* Do a sigreturn to restart the thread that
* was interrupted by a signal:
*/
_thread_sys_sigreturn(&_thread_run->saved_sigcontext);
} else {
/*
* Do a longjmp to restart the thread that
* was context switched out (by a longjmp to
* a different thread):
*/
_thread_sys_longjmp(_thread_run->saved_jmp_buf, 1);
}
/* This point should not be reached. */
PANIC("Thread has returned from sigreturn or longjmp");
}
}
/* There are no more threads, so exit this process: */
exit(0);
}
static void
_thread_signal(pthread_t pthread, int sig)
{
int done;
long l;
pthread_t new_pthread;
struct sigaction act;
void *arg;
/*
* Assume that the signal will not be dealt with according
* to the thread state:
*/
done = 0;
/* Process according to thread state: */
switch (pthread->state) {
/* States which do not change when a signal is trapped: */
case PS_COND_WAIT:
case PS_DEAD:
case PS_FDLR_WAIT:
case PS_FDLW_WAIT:
case PS_JOIN:
case PS_MUTEX_WAIT:
case PS_RUNNING:
case PS_STATE_MAX:
case PS_SIGTHREAD:
case PS_SUSPENDED:
/* Nothing to do here. */
break;
/* Wait for child: */
case PS_WAIT_WAIT:
/* Check if the signal is from a child exiting: */
if (sig == SIGCHLD) {
/* Reset the error: */
_thread_seterrno(pthread, 0);
/* Change the state of the thread to run: */
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
} else {
/* Return the 'interrupted' error: */
_thread_seterrno(pthread, EINTR);
/* Change the state of the thread to run: */
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
}
pthread->interrupted = 1;
break;
/* Waiting on I/O for zero or more file descriptors: */
case PS_SELECT_WAIT:
pthread->data.select_data->nfds = -1;
/* Return the 'interrupted' error: */
_thread_seterrno(pthread, EINTR);
pthread->interrupted = 1;
/* Change the state of the thread to run: */
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
break;
/*
* States that are interrupted by the occurrence of a signal
* other than the scheduling alarm:
*/
case PS_FDR_WAIT:
case PS_FDW_WAIT:
case PS_SLEEP_WAIT:
/* Return the 'interrupted' error: */
_thread_seterrno(pthread, EINTR);
pthread->interrupted = 1;
/* Change the state of the thread to run: */
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
/* Return the signal number: */
pthread->signo = sig;
break;
/* Waiting on a signal: */
case PS_SIGWAIT:
/* Change the state of the thread to run: */
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
/* Return the signal number: */
pthread->signo = sig;
/* Flag the signal as dealt with: */
done = 1;
break;
}
/*
* Check if this signal has been dealt with, or is being
* ignored:
*/
if (done || pthread->act[sig - 1].sa_handler == SIG_IGN) {
/* Ignore the signal for this thread. */
}
/* Check if this signal is to use the default handler: */
else if (pthread->act[sig - 1].sa_handler == SIG_DFL) {
/* Process according to signal type: */
switch (sig) {
/* Signals which cause core dumps: */
case SIGQUIT:
case SIGILL:
case SIGTRAP:
case SIGABRT:
case SIGEMT:
case SIGFPE:
case SIGBUS:
case SIGSEGV:
case SIGSYS:
/* Clear the signal action: */
sigfillset(&act.sa_mask);
act.sa_handler = SIG_DFL;
act.sa_flags = SA_RESTART;
_thread_sys_sigaction(sig, &act, NULL);
/*
* Do a sigreturn back to where the signal was
* detected and a core dump should occur:
*/
_thread_sys_sigreturn(&pthread->saved_sigcontext);
break;
/* Default processing for other signals: */
default:
/*
* ### Default processing is a problem to resolve!
* ###
*/
break;
}
} else {
/*
* Cast the signal number as a long and then to a void
* pointer. Sigh. This is POSIX.
*/
l = (long) sig;
arg = (void *) l;
/* Create a signal handler thread, but don't run it yet: */
if (_thread_create(&new_pthread, NULL, (void *) pthread->act[sig - 1].sa_handler, arg, pthread) != 0) {
/*
* Error creating signal handler thread, so abort
* this process:
*/
PANIC("Cannot create signal handler thread");
}
}
/* Nothing to return. */
return;
}
void
_thread_kern_sig_block(int *status)
{
sigset_t oset;
/*
* Block all signals so that the process will not be interrupted by
* signals:
*/
_thread_sys_sigprocmask(SIG_SETMASK, &sig_to_block, &oset);
/* Check if the caller wants the current block status returned: */
if (status != NULL) {
/* Return the previous signal block status: */
*status = (oset != 0);
}
return;
}
void
_thread_kern_sig_unblock(int status)
{
sigset_t oset;
/*
* Check if the caller thinks that signals weren't blocked when it
* called _thread_kern_sig_block:
*/
if (status == 0) {
/*
* Unblock all signals so that the process will be
* interrupted when a signal occurs:
*/
_thread_sys_sigprocmask(SIG_SETMASK, &sig_to_unblock, &oset);
}
return;
}
void
_thread_kern_sched_state(enum pthread_state state, char *fname, int lineno)
{
/* Change the state of the current thread: */
_thread_run->state = state;
_thread_run->fname = fname;
_thread_run->lineno = lineno;
/* Schedule the next thread that is ready: */
_thread_kern_sched(NULL);
return;
}
static void
_thread_kern_select(int wait_reqd)
{
char bufr[128];
fd_set fd_set_except;
fd_set fd_set_read;
fd_set fd_set_write;
int count = 0;
int count_dec;
int found_one;
int i;
int nfds = -1;
int settimeout;
pthread_t pthread;
ssize_t num;
struct timespec ts;
struct timespec ts1;
struct timeval *p_tv;
struct timeval tv;
struct timeval tv1;
/* Zero the file descriptor sets: */
FD_ZERO(&fd_set_read);
FD_ZERO(&fd_set_write);
FD_ZERO(&fd_set_except);
/* Check if the caller wants to wait: */
if (wait_reqd) {
/*
* Add the pthread kernel pipe file descriptor to the read
* set:
*/
FD_SET(_thread_kern_pipe[0], &fd_set_read);
nfds = _thread_kern_pipe[0];
/* Get the current time of day: */
gettimeofday(&tv, NULL);
TIMEVAL_TO_TIMESPEC(&tv, &ts);
}
/* Initialise the time value structure: */
tv.tv_sec = 0;
tv.tv_usec = 0;
/*
* Enter a loop to process threads waiting on either file descriptors
* or times:
*/
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
/* Assume that this state does not time out: */
settimeout = 0;
/* Process according to thread state: */
switch (pthread->state) {
/*
* States which do not depend on file descriptor I/O
* operations or timeouts:
*/
case PS_DEAD:
case PS_FDLR_WAIT:
case PS_FDLW_WAIT:
case PS_JOIN:
case PS_MUTEX_WAIT:
case PS_RUNNING:
case PS_SIGTHREAD:
case PS_SIGWAIT:
case PS_STATE_MAX:
case PS_WAIT_WAIT:
case PS_SUSPENDED:
/* Nothing to do here. */
break;
/* File descriptor read wait: */
case PS_FDR_WAIT:
/* Add the file descriptor to the read set: */
FD_SET(pthread->data.fd.fd, &fd_set_read);
/*
* Check if this file descriptor is greater than any
* of those seen so far:
*/
if (pthread->data.fd.fd > nfds) {
/* Remember this file descriptor: */
nfds = pthread->data.fd.fd;
}
/* Increment the file descriptor count: */
count++;
/* This state can time out: */
settimeout = 1;
break;
/* File descriptor write wait: */
case PS_FDW_WAIT:
/* Add the file descriptor to the write set: */
FD_SET(pthread->data.fd.fd, &fd_set_write);
/*
* Check if this file descriptor is greater than any
* of those seen so far:
*/
if (pthread->data.fd.fd > nfds) {
/* Remember this file descriptor: */
nfds = pthread->data.fd.fd;
}
/* Increment the file descriptor count: */
count++;
/* This state can time out: */
settimeout = 1;
break;
/* States that time out: */
case PS_SLEEP_WAIT:
case PS_COND_WAIT:
/* Flag a timeout as required: */
settimeout = 1;
break;
/* Select wait: */
case PS_SELECT_WAIT:
/*
* Enter a loop to process each file descriptor in
* the thread-specific file descriptor sets:
*/
for (i = 0; i < pthread->data.select_data->nfds; i++) {
/*
* Check if this file descriptor is set for
* exceptions:
*/
if (FD_ISSET(i, &pthread->data.select_data->exceptfds)) {
/*
* Add the file descriptor to the
* exception set:
*/
FD_SET(i, &fd_set_except);
/*
* Increment the file descriptor
* count:
*/
count++;
/*
* Check if this file descriptor is
* greater than any of those seen so
* far:
*/
if (i > nfds) {
/*
* Remember this file
* descriptor:
*/
nfds = i;
}
}
/*
* Check if this file descriptor is set for
* write:
*/
if (FD_ISSET(i, &pthread->data.select_data->writefds)) {
/*
* Add the file descriptor to the
* write set:
*/
FD_SET(i, &fd_set_write);
/*
* Increment the file descriptor
* count:
*/
count++;
/*
* Check if this file descriptor is
* greater than any of those seen so
* far:
*/
if (i > nfds) {
/*
* Remember this file
* descriptor:
*/
nfds = i;
}
}
/*
* Check if this file descriptor is set for
* read:
*/
if (FD_ISSET(i, &pthread->data.select_data->readfds)) {
/*
* Add the file descriptor to the
* read set:
*/
FD_SET(i, &fd_set_read);
/*
* Increment the file descriptor
* count:
*/
count++;
/*
* Check if this file descriptor is
* greater than any of those seen so
* far:
*/
if (i > nfds) {
/*
* Remember this file
* descriptor:
*/
nfds = i;
}
}
}
/* This state can time out: */
settimeout = 1;
break;
}
/*
* Check if the caller wants to wait and if the thread state
* is one that times out:
*/
if (wait_reqd && settimeout) {
/* Check if this thread wants to wait forever: */
if (pthread->wakeup_time.tv_sec == -1) {
}
/* Check if this thread doesn't want to wait at all: */
else if (pthread->wakeup_time.tv_sec == 0 &&
pthread->wakeup_time.tv_nsec == 0) {
/* Override the caller's request to wait: */
wait_reqd = 0;
} else {
/*
* Calculate the time until this thread is
* ready, allowing for the clock resolution:
*/
ts1.tv_sec = pthread->wakeup_time.tv_sec - ts.tv_sec;
ts1.tv_nsec = pthread->wakeup_time.tv_nsec - ts.tv_nsec +
CLOCK_RES_NSEC;
/*
* Check for underflow of the nanosecond
* field:
*/
if (ts1.tv_nsec < 0) {
/*
* Allow for the underflow of the
* nanosecond field:
*/
ts1.tv_sec--;
ts1.tv_nsec += 1000000000;
}
/*
* Check for overflow of the nanosecond
* field:
*/
if (ts1.tv_nsec >= 1000000000) {
/*
* Allow for the overflow of the
* nanosecond field:
*/
ts1.tv_sec++;
ts1.tv_nsec -= 1000000000;
}
/*
* Convert the timespec structure to a
* timeval structure:
*/
TIMESPEC_TO_TIMEVAL(&tv1, &ts1);
/*
* Check if no time value has been found yet,
* or if the thread will be ready sooner that
* the earliest one found so far:
*/
if ((tv.tv_sec == 0 && tv.tv_usec == 0) || timercmp(&tv1, &tv, <)) {
/* Update the time value: */
tv.tv_sec = tv1.tv_sec;
tv.tv_usec = tv1.tv_usec;
}
}
}
}
/* Check if the caller wants to wait: */
if (wait_reqd) {
/* Check if no threads were found with timeouts: */
if (tv.tv_sec == 0 && tv.tv_usec == 0) {
/* Wait forever: */
p_tv = NULL;
} else {
/*
* Point to the time value structure which contains
* the earliest time that a thread will be ready:
*/
p_tv = &tv;
}
/*
* Flag the pthread kernel as in a select. This is to avoid
* the window between the next statement that unblocks
* signals and the select statement which follows.
*/
_thread_kern_in_select = 1;
/* Unblock all signals: */
_thread_kern_sig_unblock(0);
/*
* Wait for a file descriptor to be ready for read, write, or
* an exception, or a timeout to occur:
*/
count = _thread_sys_select(nfds + 1, &fd_set_read, &fd_set_write, &fd_set_except, p_tv);
/* Block all signals again: */
_thread_kern_sig_block(NULL);
/* Reset the kernel in select flag: */
_thread_kern_in_select = 0;
/*
* Check if it is possible that there are bytes in the kernel
* read pipe waiting to be read:
*/
if (count < 0 || FD_ISSET(_thread_kern_pipe[0], &fd_set_read)) {
/*
* Check if the kernel read pipe was included in the
* count:
*/
if (count > 0) {
/*
* Remove the kernel read pipe from the
* count:
*/
FD_CLR(_thread_kern_pipe[0], &fd_set_read);
/* Decrement the count of file descriptors: */
count--;
}
/*
* Enter a loop to read (and trash) bytes from the
* pthread kernel pipe:
*/
while ((num = _thread_sys_read(_thread_kern_pipe[0], bufr, sizeof(bufr))) > 0) {
/*
* The buffer read contains one byte per
* signal and each byte is the signal number.
* This data is not used, but the fact that
* the signal handler wrote to the pipe *is*
* used to cause the _thread_sys_select call
* to complete if the signal occurred between
* the time when signals were unblocked and
* the _thread_sys_select select call being
* made.
*/
}
}
}
/* Check if there are file descriptors to poll: */
else if (count > 0) {
/*
* Point to the time value structure which has been zeroed so
* that the call to _thread_sys_select will not wait:
*/
p_tv = &tv;
/* Poll file descrptors without wait: */
count = _thread_sys_select(nfds + 1, &fd_set_read, &fd_set_write, &fd_set_except, p_tv);
}
/*
* Check if the select call was interrupted, or some other error
* occurred:
*/
if (count < 0) {
/* Check if the select call was interrupted: */
if (errno == EINTR) {
/*
* Interrupted calls are expected. The interrupting
* signal will be in the sigpend array.
*/
} else {
/* This should not occur: */
}
}
/* Check if no file descriptors are ready: */
else if (count == 0) {
/* Nothing to do here. */
} else {
/*
* Enter a loop to look for threads waiting on file
* descriptors that are flagged as available by the
* _thread_sys_select syscall:
*/
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
/* Process according to thread state: */
switch (pthread->state) {
/*
* States which do not depend on file
* descriptor I/O operations:
*/
case PS_RUNNING:
case PS_COND_WAIT:
case PS_DEAD:
case PS_FDLR_WAIT:
case PS_FDLW_WAIT:
case PS_JOIN:
case PS_MUTEX_WAIT:
case PS_SIGWAIT:
case PS_SLEEP_WAIT:
case PS_WAIT_WAIT:
case PS_SIGTHREAD:
case PS_STATE_MAX:
case PS_SUSPENDED:
/* Nothing to do here. */
break;
/* File descriptor read wait: */
case PS_FDR_WAIT:
/*
* Check if the file descriptor is available
* for read:
*/
if (FD_ISSET(pthread->data.fd.fd, &fd_set_read)) {
/*
* Change the thread state to allow
* it to read from the file when it
* is scheduled next:
*/
pthread->state = PS_RUNNING;
}
break;
/* File descriptor write wait: */
case PS_FDW_WAIT:
/*
* Check if the file descriptor is available
* for write:
*/
if (FD_ISSET(pthread->data.fd.fd, &fd_set_write)) {
/*
* Change the thread state to allow
* it to write to the file when it is
* scheduled next:
*/
pthread->state = PS_RUNNING;
}
break;
/* Select wait: */
case PS_SELECT_WAIT:
/*
* Reset the flag that indicates if a file
* descriptor is ready for some type of
* operation:
*/
count_dec = 0;
/*
* Enter a loop to search though the
* thread-specific select file descriptors
* for the first descriptor that is ready:
*/
for (i = 0; i < pthread->data.select_data->nfds && count_dec == 0; i++) {
/*
* Check if this file descriptor does
* not have an exception:
*/
if (FD_ISSET(i, &pthread->data.select_data->exceptfds) && FD_ISSET(i, &fd_set_except)) {
/*
* Flag this file descriptor
* as ready:
*/
count_dec = 1;
}
/*
* Check if this file descriptor is
* not ready for write:
*/
if (FD_ISSET(i, &pthread->data.select_data->writefds) && FD_ISSET(i, &fd_set_write)) {
/*
* Flag this file descriptor
* as ready:
*/
count_dec = 1;
}
/*
* Check if this file descriptor is
* not ready for read:
*/
if (FD_ISSET(i, &pthread->data.select_data->readfds) && FD_ISSET(i, &fd_set_read)) {
/*
* Flag this file descriptor
* as ready:
*/
count_dec = 1;
}
}
/*
* Check if any file descriptors are ready
* for the current thread:
*/
if (count_dec) {
/*
* Reset the count of file
* descriptors that are ready for
* this thread:
*/
found_one = 0;
/*
* Enter a loop to search though the
* thread-specific select file
* descriptors:
*/
for (i = 0; i < pthread->data.select_data->nfds; i++) {
/*
* Reset the count of
* operations for which the
* current file descriptor is
* ready:
*/
count_dec = 0;
/*
* Check if this file
* descriptor is selected for
* exceptions:
*/
if (FD_ISSET(i, &pthread->data.select_data->exceptfds)) {
/*
* Check if this file
* descriptor has an
* exception:
*/
if (FD_ISSET(i, &fd_set_except)) {
/*
* Increment
* the count
* for this
* file:
*/
count_dec++;
} else {
/*
* Clear the
* file
* descriptor
* in the
* thread-spec
* ific file
* descriptor
* set:
*/
FD_CLR(i, &pthread->data.select_data->exceptfds);
}
}
/*
* Check if this file
* descriptor is selected for
* write:
*/
if (FD_ISSET(i, &pthread->data.select_data->writefds)) {
/*
* Check if this file
* descriptor is
* ready for write:
*/
if (FD_ISSET(i, &fd_set_write)) {
/*
* Increment
* the count
* for this
* file:
*/
count_dec++;
} else {
/*
* Clear the
* file
* descriptor
* in the
* thread-spec
* ific file
* descriptor
* set:
*/
FD_CLR(i, &pthread->data.select_data->writefds);
}
}
/*
* Check if this file
* descriptor is selected for
* read:
*/
if (FD_ISSET(i, &pthread->data.select_data->readfds)) {
/*
* Check if this file
* descriptor is
* ready for read:
*/
if (FD_ISSET(i, &fd_set_read)) {
/*
* Increment
* the count
* for this
* file:
*/
count_dec++;
} else {
/*
* Clear the
* file
* descriptor
* in the
* thread-spec
* ific file
* descriptor
* set:
*/
FD_CLR(i, &pthread->data.select_data->readfds);
}
}
/*
* Check if the current file
* descriptor is ready for
* any one of the operations:
*/
if (count_dec > 0) {
/*
* Increment the
* count of file
* descriptors that
* are ready for the
* current thread:
*/
found_one++;
}
}
/*
* Return the number of file
* descriptors that are ready:
*/
pthread->data.select_data->nfds = found_one;
/*
* Change the state of the current
* thread to run:
*/
pthread->state = PS_RUNNING;
}
break;
}
}
}
/* Nothing to return. */
return;
}
void
_thread_kern_set_timeout(struct timespec * timeout)
{
struct timespec current_time;
struct timeval tv;
/* Reset the timeout flag for the running thread: */
_thread_run->timeout = 0;
/* Check if the thread is to wait forever: */
if (timeout == NULL) {
/*
* Set the wakeup time to something that can be recognised as
* different to an actual time of day:
*/
_thread_run->wakeup_time.tv_sec = -1;
_thread_run->wakeup_time.tv_nsec = -1;
}
/* Check if no waiting is required: */
else if (timeout->tv_sec == 0 && timeout->tv_nsec == 0) {
/* Set the wake up time to 'immediately': */
_thread_run->wakeup_time.tv_sec = 0;
_thread_run->wakeup_time.tv_nsec = 0;
} else {
/* Get the current time: */
gettimeofday(&tv, NULL);
TIMEVAL_TO_TIMESPEC(&tv, ¤t_time);
/* Calculate the time for the current thread to wake up: */
_thread_run->wakeup_time.tv_sec = current_time.tv_sec + timeout->tv_sec;
_thread_run->wakeup_time.tv_nsec = current_time.tv_nsec + timeout->tv_nsec;
/* Check if the nanosecond field needs to wrap: */
if (_thread_run->wakeup_time.tv_nsec >= 1000000000) {
/* Wrap the nanosecond field: */
_thread_run->wakeup_time.tv_sec += 1;
_thread_run->wakeup_time.tv_nsec -= 1000000000;
}
}
return;
}
#endif
|