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
|
/*
B G E T
Buffer allocator
Designed and implemented in April of 1972 by John Walker, based on the
Case Algol OPRO$ algorithm implemented in 1966.
Reimplemented in 1975 by John Walker for the Interdata 70.
Reimplemented in 1977 by John Walker for the Marinchip 9900.
Reimplemented in 1982 by Duff Kurland for the Intel 8080.
Portable C version implemented in September of 1990 by an older, wiser
instance of the original implementor.
Souped up and/or weighed down slightly shortly thereafter by Greg
Lutz.
AMIX edition, including the new compaction call-back option, prepared
by John Walker in July of 1992.
Bug in built-in test program fixed, ANSI compiler warnings eradicated,
buffer pool validator implemented, and guaranteed repeatable test
added by John Walker in October of 1995.
This program is in the public domain.
1. This is the book of the generations of Adam. In the day that God
created man, in the likeness of God made he him;
2. Male and female created he them; and blessed them, and called
their name Adam, in the day when they were created.
3. And Adam lived an hundred and thirty years, and begat a son in
his own likeness, and after his image; and called his name Seth:
4. And the days of Adam after he had begotten Seth were eight
hundred years: and he begat sons and daughters:
5. And all the days that Adam lived were nine hundred and thirty
years: and he died.
6. And Seth lived an hundred and five years, and begat Enos:
7. And Seth lived after he begat Enos eight hundred and seven years,
and begat sons and daughters:
8. And all the days of Seth were nine hundred and twelve years: and
he died.
9. And Enos lived ninety years, and begat Cainan:
10. And Enos lived after he begat Cainan eight hundred and fifteen
years, and begat sons and daughters:
11. And all the days of Enos were nine hundred and five years: and
he died.
12. And Cainan lived seventy years and begat Mahalaleel:
13. And Cainan lived after he begat Mahalaleel eight hundred and
forty years, and begat sons and daughters:
14. And all the days of Cainan were nine hundred and ten years: and
he died.
15. And Mahalaleel lived sixty and five years, and begat Jared:
16. And Mahalaleel lived after he begat Jared eight hundred and
thirty years, and begat sons and daughters:
17. And all the days of Mahalaleel were eight hundred ninety and
five years: and he died.
18. And Jared lived an hundred sixty and two years, and he begat
Enoch:
19. And Jared lived after he begat Enoch eight hundred years, and
begat sons and daughters:
20. And all the days of Jared were nine hundred sixty and two years:
and he died.
21. And Enoch lived sixty and five years, and begat Methuselah:
22. And Enoch walked with God after he begat Methuselah three
hundred years, and begat sons and daughters:
23. And all the days of Enoch were three hundred sixty and five
years:
24. And Enoch walked with God: and he was not; for God took him.
25. And Methuselah lived an hundred eighty and seven years, and
begat Lamech.
26. And Methuselah lived after he begat Lamech seven hundred eighty
and two years, and begat sons and daughters:
27. And all the days of Methuselah were nine hundred sixty and nine
years: and he died.
28. And Lamech lived an hundred eighty and two years, and begat a
son:
29. And he called his name Noah, saying, This same shall comfort us
concerning our work and toil of our hands, because of the ground
which the LORD hath cursed.
30. And Lamech lived after he begat Noah five hundred ninety and
five years, and begat sons and daughters:
31. And all the days of Lamech were seven hundred seventy and seven
years: and he died.
32. And Noah was five hundred years old: and Noah begat Shem, Ham,
and Japheth.
And buffers begat buffers, and links begat links, and buffer pools
begat links to chains of buffer pools containing buffers, and lo the
buffers and links and pools of buffers and pools of links to chains of
pools of buffers were fruitful and they multiplied and the Operating
System looked down upon them and said that it was Good.
INTRODUCTION
============
BGET is a comprehensive memory allocation package which is easily
configured to the needs of an application. BGET is efficient in
both the time needed to allocate and release buffers and in the
memory overhead required for buffer pool management. It
automatically consolidates contiguous space to minimise
fragmentation. BGET is configured by compile-time definitions,
Major options include:
* A built-in test program to exercise BGET and
demonstrate how the various functions are used.
* Allocation by either the "first fit" or "best fit"
method.
* Wiping buffers at release time to catch code which
references previously released storage.
* Built-in routines to dump individual buffers or the
entire buffer pool.
* Retrieval of allocation and pool size statistics.
* Quantisation of buffer sizes to a power of two to
satisfy hardware alignment constraints.
* Automatic pool compaction, growth, and shrinkage by
means of call-backs to user defined functions.
Applications of BGET can range from storage management in
ROM-based embedded programs to providing the framework upon which
a multitasking system incorporating garbage collection is
constructed. BGET incorporates extensive internal consistency
checking using the <assert.h> mechanism; all these checks can be
turned off by compiling with NDEBUG defined, yielding a version of
BGET with minimal size and maximum speed.
The basic algorithm underlying BGET has withstood the test of
time; more than 25 years have passed since the first
implementation of this code. And yet, it is substantially more
efficient than the native allocation schemes of many operating
systems: the Macintosh and Microsoft Windows to name two, on which
programs have obtained substantial speed-ups by layering BGET as
an application level memory manager atop the underlying system's.
BGET has been implemented on the largest mainframes and the lowest
of microprocessors. It has served as the core for multitasking
operating systems, multi-thread applications, embedded software in
data network switching processors, and a host of C programs. And
while it has accreted flexibility and additional options over the
years, it remains fast, memory efficient, portable, and easy to
integrate into your program.
BGET IMPLEMENTATION ASSUMPTIONS
===============================
BGET is written in as portable a dialect of C as possible. The
only fundamental assumption about the underlying hardware
architecture is that memory is allocated is a linear array which
can be addressed as a vector of C "char" objects. On segmented
address space architectures, this generally means that BGET should
be used to allocate storage within a single segment (although some
compilers simulate linear address spaces on segmented
architectures). On segmented architectures, then, BGET buffer
pools may not be larger than a segment, but since BGET allows any
number of separate buffer pools, there is no limit on the total
storage which can be managed, only on the largest individual
object which can be allocated. Machines with a linear address
architecture, such as the VAX, 680x0, Sparc, MIPS, or the Intel
80386 and above in native mode, may use BGET without restriction.
GETTING STARTED WITH BGET
=========================
Although BGET can be configured in a multitude of fashions, there
are three basic ways of working with BGET. The functions
mentioned below are documented in the following section. Please
excuse the forward references which are made in the interest of
providing a roadmap to guide you to the BGET functions you're
likely to need.
Embedded Applications
---------------------
Embedded applications typically have a fixed area of memory
dedicated to buffer allocation (often in a separate RAM address
space distinct from the ROM that contains the executable code).
To use BGET in such an environment, simply call bpool() with the
start address and length of the buffer pool area in RAM, then
allocate buffers with bget() and release them with brel().
Embedded applications with very limited RAM but abundant CPU speed
may benefit by configuring BGET for BestFit allocation (which is
usually not worth it in other environments).
Malloc() Emulation
------------------
If the C library malloc() function is too slow, not present in
your development environment (for example, an a native Windows or
Macintosh program), or otherwise unsuitable, you can replace it
with BGET. Initially define a buffer pool of an appropriate size
with bpool()--usually obtained by making a call to the operating
system's low-level memory allocator. Then allocate buffers with
bget(), bgetz(), and bgetr() (the last two permit the allocation
of buffers initialised to zero and [inefficient] re-allocation of
existing buffers for compatibility with C library functions).
Release buffers by calling brel(). If a buffer allocation request
fails, obtain more storage from the underlying operating system,
add it to the buffer pool by another call to bpool(), and continue
execution.
Automatic Storage Management
----------------------------
You can use BGET as your application's native memory manager and
implement automatic storage pool expansion, contraction, and
optionally application-specific memory compaction by compiling
BGET with the BECtl variable defined, then calling bectl() and
supplying functions for storage compaction, acquisition, and
release, as well as a standard pool expansion increment. All of
these functions are optional (although it doesn't make much sense
to provide a release function without an acquisition function,
does it?). Once the call-back functions have been defined with
bectl(), you simply use bget() and brel() to allocate and release
storage as before. You can supply an initial buffer pool with
bpool() or rely on automatic allocation to acquire the entire
pool. When a call on bget() cannot be satisfied, BGET first
checks if a compaction function has been supplied. If so, it is
called (with the space required to satisfy the allocation request
and a sequence number to allow the compaction routine to be called
successively without looping). If the compaction function is able
to free any storage (it needn't know whether the storage it freed
was adequate) it should return a nonzero value, whereupon BGET
will retry the allocation request and, if it fails again, call the
compaction function again with the next-higher sequence number.
If the compaction function returns zero, indicating failure to
free space, or no compaction function is defined, BGET next tests
whether a non-NULL allocation function was supplied to bectl().
If so, that function is called with an argument indicating how
many bytes of additional space are required. This will be the
standard pool expansion increment supplied in the call to bectl()
unless the original bget() call requested a buffer larger than
this; buffers larger than the standard pool block can be managed
"off the books" by BGET in this mode. If the allocation function
succeeds in obtaining the storage, it returns a pointer to the new
block and BGET expands the buffer pool; if it fails, the
allocation request fails and returns NULL to the caller. If a
non-NULL release function is supplied, expansion blocks which
become totally empty are released to the global free pool by
passing their addresses to the release function.
Equipped with appropriate allocation, release, and compaction
functions, BGET can be used as part of very sophisticated memory
management strategies, including garbage collection. (Note,
however, that BGET is *not* a garbage collector by itself, and
that developing such a system requires much additional logic and
careful design of the application's memory allocation strategy.)
BGET FUNCTION DESCRIPTIONS
==========================
Functions implemented in this file (some are enabled by certain of
the optional settings below):
void bpool(void *buffer, bufsize len);
Create a buffer pool of <len> bytes, using the storage starting at
<buffer>. You can call bpool() subsequently to contribute
additional storage to the overall buffer pool.
void *bget(bufsize size);
Allocate a buffer of <size> bytes. The address of the buffer is
returned, or NULL if insufficient memory was available to allocate
the buffer.
void *bgetz(bufsize size);
Allocate a buffer of <size> bytes and clear it to all zeroes. The
address of the buffer is returned, or NULL if insufficient memory
was available to allocate the buffer.
void *bgetr(void *buffer, bufsize newsize);
Reallocate a buffer previously allocated by bget(), changing its
size to <newsize> and preserving all existing data. NULL is
returned if insufficient memory is available to reallocate the
buffer, in which case the original buffer remains intact.
void brel(void *buf);
Return the buffer <buf>, previously allocated by bget(), to the
free space pool.
void bectl(int (*compact)(bufsize sizereq, int sequence),
void *(*acquire)(bufsize size),
void (*release)(void *buf),
bufsize pool_incr);
Expansion control: specify functions through which the package may
compact storage (or take other appropriate action) when an
allocation request fails, and optionally automatically acquire
storage for expansion blocks when necessary, and release such
blocks when they become empty. If <compact> is non-NULL, whenever
a buffer allocation request fails, the <compact> function will be
called with arguments specifying the number of bytes (total buffer
size, including header overhead) required to satisfy the
allocation request, and a sequence number indicating the number of
consecutive calls on <compact> attempting to satisfy this
allocation request. The sequence number is 1 for the first call
on <compact> for a given allocation request, and increments on
subsequent calls, permitting the <compact> function to take
increasingly dire measures in an attempt to free up storage. If
the <compact> function returns a nonzero value, the allocation
attempt is re-tried. If <compact> returns 0 (as it must if it
isn't able to release any space or add storage to the buffer
pool), the allocation request fails, which can trigger automatic
pool expansion if the <acquire> argument is non-NULL. At the time
the <compact> function is called, the state of the buffer
allocator is identical to that at the moment the allocation
request was made; consequently, the <compact> function may call
brel(), bpool(), bstats(), and/or directly manipulate the buffer
pool in any manner which would be valid were the application in
control. This does not, however, relieve the <compact> function
of the need to ensure that whatever actions it takes do not change
things underneath the application that made the allocation
request. For example, a <compact> function that released a buffer
in the process of being reallocated with bgetr() would lead to
disaster. Implementing a safe and effective <compact> mechanism
requires careful design of an application's memory architecture,
and cannot generally be easily retrofitted into existing code.
If <acquire> is non-NULL, that function will be called whenever an
allocation request fails. If the <acquire> function succeeds in
allocating the requested space and returns a pointer to the new
area, allocation will proceed using the expanded buffer pool. If
<acquire> cannot obtain the requested space, it should return NULL
and the entire allocation process will fail. <pool_incr>
specifies the normal expansion block size. Providing an <acquire>
function will cause subsequent bget() requests for buffers too
large to be managed in the linked-block scheme (in other words,
larger than <pool_incr> minus the buffer overhead) to be satisfied
directly by calls to the <acquire> function. Automatic release of
empty pool blocks will occur only if all pool blocks in the system
are the size given by <pool_incr>.
void bstats(bufsize *curalloc, bufsize *totfree,
bufsize *maxfree, long *nget, long *nrel);
The amount of space currently allocated is stored into the
variable pointed to by <curalloc>. The total free space (sum of
all free blocks in the pool) is stored into the variable pointed
to by <totfree>, and the size of the largest single block in the
free space pool is stored into the variable pointed to by
<maxfree>. The variables pointed to by <nget> and <nrel> are
filled, respectively, with the number of successful (non-NULL
return) bget() calls and the number of brel() calls.
void bstatse(bufsize *pool_incr, long *npool,
long *npget, long *nprel,
long *ndget, long *ndrel);
Extended statistics: The expansion block size will be stored into
the variable pointed to by <pool_incr>, or the negative thereof if
automatic expansion block releases are disabled. The number of
currently active pool blocks will be stored into the variable
pointed to by <npool>. The variables pointed to by <npget> and
<nprel> will be filled with, respectively, the number of expansion
block acquisitions and releases which have occurred. The
variables pointed to by <ndget> and <ndrel> will be filled with
the number of bget() and brel() calls, respectively, managed
through blocks directly allocated by the acquisition and release
functions.
void bufdump(void *buf);
The buffer pointed to by <buf> is dumped on standard output.
void bpoold(void *pool, int dumpalloc, int dumpfree);
All buffers in the buffer pool <pool>, previously initialised by a
call on bpool(), are listed in ascending memory address order. If
<dumpalloc> is nonzero, the contents of allocated buffers are
dumped; if <dumpfree> is nonzero, the contents of free blocks are
dumped.
int bpoolv(void *pool);
The named buffer pool, previously initialised by a call on
bpool(), is validated for bad pointers, overwritten data, etc. If
compiled with NDEBUG not defined, any error generates an assertion
failure. Otherwise 1 is returned if the pool is valid, 0 if an
error is found.
BGET CONFIGURATION
==================
*/
/*
* THIS SOFTWARE IS PROVIDED "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 ST 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.
*/
/* #define BGET_ENABLE_ALL_OPTIONS */
#ifdef BGET_ENABLE_OPTION
#define TestProg 20000 /* Generate built-in test program
if defined. The value specifies
how many buffer allocation attempts
the test program should make. */
#define SizeQuant 4 /* Buffer allocation size quantum:
all buffers allocated are a
multiple of this size. This
MUST be a power of two. */
#define BufDump 1 /* Define this symbol to enable the
bpoold() function which dumps the
buffers in a buffer pool. */
#define BufValid 1 /* Define this symbol to enable the
bpoolv() function for validating
a buffer pool. */
#define DumpData 1 /* Define this symbol to enable the
bufdump() function which allows
dumping the contents of an allocated
or free buffer. */
#define BufStats 1 /* Define this symbol to enable the
bstats() function which calculates
the total free space in the buffer
pool, the largest available
buffer, and the total space
currently allocated. */
#define FreeWipe 1 /* Wipe free buffers to a guaranteed
pattern of garbage to trip up
miscreants who attempt to use
pointers into released buffers. */
#define BestFit 1 /* Use a best fit algorithm when
searching for space for an
allocation request. This uses
memory more efficiently, but
allocation will be much slower. */
#define BECtl 1 /* Define this symbol to enable the
bectl() function for automatic
pool space control. */
#endif
#include <stdio.h>
#include <stdbool.h>
#ifdef lint
#define NDEBUG /* Exits in asserts confuse lint */
/* LINTLIBRARY */ /* Don't complain about def, no ref */
extern char *sprintf(); /* Sun includes don't define sprintf */
#endif
#include <assert.h>
#include <memory.h>
#ifdef BufDump /* BufDump implies DumpData */
#ifndef DumpData
#define DumpData 1
#endif
#endif
#ifdef DumpData
#include <ctype.h>
#endif
#ifdef __KERNEL__
#ifdef CFG_CORE_BGET_BESTFIT
#define BestFit 1
#endif
#endif
/* Declare the interface, including the requested buffer size type,
bufsize. */
#include "bget.h"
#define MemSize int /* Type for size arguments to memxxx()
functions such as memcmp(). */
/* Queue links */
struct qlinks {
struct bfhead *flink; /* Forward link */
struct bfhead *blink; /* Backward link */
};
/* Header in allocated and free buffers */
struct bhead {
bufsize prevfree; /* Relative link back to previous
free buffer in memory or 0 if
previous buffer is allocated. */
bufsize bsize; /* Buffer size: positive if free,
negative if allocated. */
};
#define BH(p) ((struct bhead *) (p))
/* Header in directly allocated buffers (by acqfcn) */
struct bdhead {
bufsize tsize; /* Total size, including overhead */
struct bhead bh; /* Common header */
};
#define BDH(p) ((struct bdhead *) (p))
/* Header in free buffers */
struct bfhead {
struct bhead bh; /* Common allocated/free header */
struct qlinks ql; /* Links on free list */
};
#define BFH(p) ((struct bfhead *) (p))
/* Poolset definition */
struct bpoolset {
struct bfhead freelist;
#ifdef BufStats
bufsize totalloc; /* Total space currently allocated */
long numget; /* Number of bget() calls */
long numrel; /* Number of brel() calls */
#ifdef BECtl
long numpblk; /* Number of pool blocks */
long numpget; /* Number of block gets and rels */
long numprel;
long numdget; /* Number of direct gets and rels */
long numdrel;
#endif /* BECtl */
#endif /* BufStats */
#ifdef BECtl
/* Automatic expansion block management functions */
int (*compfcn) _((bufsize sizereq, int sequence));
void *(*acqfcn) _((bufsize size));
void (*relfcn) _((void *buf));
bufsize exp_incr; /* Expansion block size */
bufsize pool_len; /* 0: no bpool calls have been made
-1: not all pool blocks are
the same size
>0: (common) block size for all
bpool calls made so far
*/
#endif
};
/* Minimum allocation quantum: */
#define QLSize (sizeof(struct qlinks))
#define SizeQ ((SizeQuant > QLSize) ? SizeQuant : QLSize)
#define V (void) /* To denote unwanted returned values */
/* End sentinel: value placed in bsize field of dummy block delimiting
end of pool block. The most negative number which will fit in a
bufsize, defined in a way that the compiler will accept. */
#define ESent ((bufsize) (-(((1L << (sizeof(bufsize) * 8 - 2)) - 1) * 2) - 2))
/* BGET -- Allocate a buffer. */
void *bget(requested_size, poolset)
bufsize requested_size;
struct bpoolset *poolset;
{
bufsize size = requested_size;
struct bfhead *b;
#ifdef BestFit
struct bfhead *best;
#endif
void *buf;
#ifdef BECtl
int compactseq = 0;
#endif
assert(size > 0);
if (size < SizeQ) { /* Need at least room for the */
size = SizeQ; /* queue links. */
}
#ifdef SizeQuant
#if SizeQuant > 1
if (ADD_OVERFLOW(size, SizeQuant - 1, &size))
return NULL;
size = ROUNDDOWN(size, SizeQuant);
#endif
#endif
/* Add overhead in allocated buffer to size required. */
if (ADD_OVERFLOW(size, sizeof(struct bhead), &size))
return NULL;
#ifdef BECtl
/* If a compact function was provided in the call to bectl(), wrap
a loop around the allocation process to allow compaction to
intervene in case we don't find a suitable buffer in the chain. */
while (1) {
#endif
b = poolset->freelist.ql.flink;
#ifdef BestFit
best = &poolset->freelist;
#endif
/* Scan the free list searching for the first buffer big enough
to hold the requested size buffer. */
#ifdef BestFit
while (b != &poolset->freelist) {
if (b->bh.bsize >= size) {
if ((best == &poolset->freelist) ||
(b->bh.bsize < best->bh.bsize)) {
best = b;
}
}
b = b->ql.flink; /* Link to next buffer */
}
b = best;
#endif /* BestFit */
while (b != &poolset->freelist) {
if ((bufsize) b->bh.bsize >= size) {
/* Buffer is big enough to satisfy the request. Allocate it
to the caller. We must decide whether the buffer is large
enough to split into the part given to the caller and a
free buffer that remains on the free list, or whether the
entire buffer should be removed from the free list and
given to the caller in its entirety. We only split the
buffer if enough room remains for a header plus the minimum
quantum of allocation. */
if ((b->bh.bsize - size) > (SizeQ + (sizeof(struct bhead)))) {
struct bhead *ba, *bn;
ba = BH(((char *) b) + (b->bh.bsize - size));
bn = BH(((char *) ba) + size);
assert(bn->prevfree == b->bh.bsize);
/* Subtract size from length of free block. */
b->bh.bsize -= size;
/* Link allocated buffer to the previous free buffer. */
ba->prevfree = b->bh.bsize;
/* Plug negative size into user buffer. */
ba->bsize = -(bufsize) size;
/* Mark buffer after this one not preceded by free block. */
bn->prevfree = 0;
#ifdef BufStats
poolset->totalloc += size;
poolset->numget++; /* Increment number of bget() calls */
#endif
buf = (void *) ((((char *) ba) + sizeof(struct bhead)));
tag_asan_alloced(buf, size);
return buf;
} else {
struct bhead *ba;
ba = BH(((char *) b) + b->bh.bsize);
assert(ba->prevfree == b->bh.bsize);
/* The buffer isn't big enough to split. Give the whole
shebang to the caller and remove it from the free list. */
assert(b->ql.blink->ql.flink == b);
assert(b->ql.flink->ql.blink == b);
b->ql.blink->ql.flink = b->ql.flink;
b->ql.flink->ql.blink = b->ql.blink;
#ifdef BufStats
poolset->totalloc += b->bh.bsize;
poolset->numget++; /* Increment number of bget() calls */
#endif
/* Negate size to mark buffer allocated. */
b->bh.bsize = -(b->bh.bsize);
/* Zero the back pointer in the next buffer in memory
to indicate that this buffer is allocated. */
ba->prevfree = 0;
/* Give user buffer starting at queue links. */
buf = (void *) &(b->ql);
tag_asan_alloced(buf, size);
return buf;
}
}
b = b->ql.flink; /* Link to next buffer */
}
#ifdef BECtl
/* We failed to find a buffer. If there's a compact function
defined, notify it of the size requested. If it returns
TRUE, try the allocation again. */
if ((poolset->compfcn == NULL) ||
(!(poolset->compfcn)(size, ++compactseq))) {
break;
}
}
/* No buffer available with requested size free. */
/* Don't give up yet -- look in the reserve supply. */
if (poolset->acqfcn != NULL) {
if (size > exp_incr - sizeof(struct bhead)) {
/* Request is too large to fit in a single expansion
block. Try to satisy it by a direct buffer acquisition. */
struct bdhead *bdh;
size += sizeof(struct bdhead) - sizeof(struct bhead);
if ((bdh = BDH((*acqfcn)((bufsize) size))) != NULL) {
/* Mark the buffer special by setting the size field
of its header to zero. */
bdh->bh.bsize = 0;
bdh->bh.prevfree = 0;
bdh->tsize = size;
#ifdef BufStats
poolset->totalloc += size;
poolset->numget++; /* Increment number of bget() calls */
poolset->numdget++; /* Direct bget() call count */
#endif
buf = (void *) (bdh + 1);
tag_asan_alloced(buf, size);
return buf;
}
} else {
/* Try to obtain a new expansion block */
void *newpool;
if ((newpool = poolset->acqfcn((bufsize) exp_incr)) != NULL) {
bpool(newpool, exp_incr, poolset);
buf = bget(requested_size, pool); /* This can't, I say, can't
get into a loop. */
return buf;
}
}
}
/* Still no buffer available */
#endif /* BECtl */
return NULL;
}
/* BGETZ -- Allocate a buffer and clear its contents to zero. We clear
the entire contents of the buffer to zero, not just the
region requested by the caller. */
void *bgetz(size, poolset)
bufsize size;
struct bpoolset *poolset;
{
char *buf = (char *) bget(size, poolset);
if (buf != NULL) {
struct bhead *b;
bufsize rsize;
b = BH(buf - sizeof(struct bhead));
rsize = -(b->bsize);
if (rsize == 0) {
struct bdhead *bd;
bd = BDH(buf - sizeof(struct bdhead));
rsize = bd->tsize - sizeof(struct bdhead);
} else {
rsize -= sizeof(struct bhead);
}
assert(rsize >= size);
V memset_unchecked(buf, 0, (MemSize) rsize);
}
return ((void *) buf);
}
/* BGETR -- Reallocate a buffer. This is a minimal implementation,
simply in terms of brel() and bget(). It could be
enhanced to allow the buffer to grow into adjacent free
blocks and to avoid moving data unnecessarily. */
void *bgetr(buf, size, poolset)
void *buf;
bufsize size;
struct bpoolset *poolset;
{
void *nbuf;
bufsize osize; /* Old size of buffer */
struct bhead *b;
if ((nbuf = bget(size, poolset)) == NULL) { /* Acquire new buffer */
return NULL;
}
if (buf == NULL) {
return nbuf;
}
b = BH(((char *) buf) - sizeof(struct bhead));
osize = -b->bsize;
#ifdef BECtl
if (osize == 0) {
/* Buffer acquired directly through acqfcn. */
struct bdhead *bd;
bd = BDH(((char *) buf) - sizeof(struct bdhead));
osize = bd->tsize - sizeof(struct bdhead);
} else
#endif
osize -= sizeof(struct bhead);
assert(osize > 0);
V memcpy((char *) nbuf, (char *) buf, /* Copy the data */
(MemSize) ((size < osize) ? size : osize));
#ifndef __KERNEL__
/* User space reallocations are always zeroed */
if (size > osize)
V memset((char *) nbuf + osize, 0, size - osize);
#endif
brel(buf, poolset, false /* !wipe */);
return nbuf;
}
/* BREL -- Release a buffer. */
void brel(buf, poolset, wipe)
void *buf;
struct bpoolset *poolset;
int wipe;
{
struct bfhead *b, *bn;
bufsize bs;
b = BFH(((char *) buf) - sizeof(struct bhead));
#ifdef BufStats
poolset->numrel++; /* Increment number of brel() calls */
#endif
assert(buf != NULL);
#ifdef FreeWipe
wipe = true;
#endif
#ifdef BECtl
if (b->bh.bsize == 0) { /* Directly-acquired buffer? */
struct bdhead *bdh;
bdh = BDH(((char *) buf) - sizeof(struct bdhead));
assert(b->bh.prevfree == 0);
#ifdef BufStats
poolset->totalloc -= bdh->tsize;
assert(poolset->totalloc >= 0);
poolset->numdrel++; /* Number of direct releases */
#endif /* BufStats */
if (wipe) {
V memset_unchecked((char *) buf, 0x55,
(MemSize) (bdh->tsize -
sizeof(struct bdhead)));
}
bs = bdh->tsize - sizeof(struct bdhead);
assert(poolset->relfcn != NULL);
poolset->relfcn((void *) bdh); /* Release it directly. */
tag_asan_free(buf, bs);
return;
}
#endif /* BECtl */
/* Buffer size must be negative, indicating that the buffer is
allocated. */
if (b->bh.bsize >= 0) {
bn = NULL;
}
assert(b->bh.bsize < 0);
bs = -b->bh.bsize;
/* Back pointer in next buffer must be zero, indicating the
same thing: */
assert(BH((char *) b - b->bh.bsize)->prevfree == 0);
#ifdef BufStats
poolset->totalloc += b->bh.bsize;
assert(poolset->totalloc >= 0);
#endif
/* If the back link is nonzero, the previous buffer is free. */
if (b->bh.prevfree != 0) {
/* The previous buffer is free. Consolidate this buffer with it
by adding the length of this buffer to the previous free
buffer. Note that we subtract the size in the buffer being
released, since it's negative to indicate that the buffer is
allocated. */
register bufsize size = b->bh.bsize;
/* Make the previous buffer the one we're working on. */
assert(BH((char *) b - b->bh.prevfree)->bsize == b->bh.prevfree);
b = BFH(((char *) b) - b->bh.prevfree);
b->bh.bsize -= size;
} else {
/* The previous buffer isn't allocated. Insert this buffer
on the free list as an isolated free block. */
assert(poolset->freelist.ql.blink->ql.flink == &poolset->freelist);
assert(poolset->freelist.ql.flink->ql.blink == &poolset->freelist);
b->ql.flink = &poolset->freelist;
b->ql.blink = poolset->freelist.ql.blink;
poolset->freelist.ql.blink = b;
b->ql.blink->ql.flink = b;
b->bh.bsize = -b->bh.bsize;
}
/* Now we look at the next buffer in memory, located by advancing from
the start of this buffer by its size, to see if that buffer is
free. If it is, we combine this buffer with the next one in
memory, dechaining the second buffer from the free list. */
bn = BFH(((char *) b) + b->bh.bsize);
if (bn->bh.bsize > 0) {
/* The buffer is free. Remove it from the free list and add
its size to that of our buffer. */
assert(BH((char *) bn + bn->bh.bsize)->prevfree == bn->bh.bsize);
assert(bn->ql.blink->ql.flink == bn);
assert(bn->ql.flink->ql.blink == bn);
bn->ql.blink->ql.flink = bn->ql.flink;
bn->ql.flink->ql.blink = bn->ql.blink;
b->bh.bsize += bn->bh.bsize;
/* Finally, advance to the buffer that follows the newly
consolidated free block. We must set its backpointer to the
head of the consolidated free block. We know the next block
must be an allocated block because the process of recombination
guarantees that two free blocks will never be contiguous in
memory. */
bn = BFH(((char *) b) + b->bh.bsize);
}
if (wipe) {
V memset_unchecked(((char *) b) + sizeof(struct bfhead), 0x55,
(MemSize) (b->bh.bsize - sizeof(struct bfhead)));
}
assert(bn->bh.bsize < 0);
/* The next buffer is allocated. Set the backpointer in it to point
to this buffer; the previous free buffer in memory. */
bn->bh.prevfree = b->bh.bsize;
#ifdef BECtl
/* If a block-release function is defined, and this free buffer
constitutes the entire block, release it. Note that pool_len
is defined in such a way that the test will fail unless all
pool blocks are the same size. */
if (poolset->relfcn != NULL &&
((bufsize) b->bh.bsize) == (pool_len - sizeof(struct bhead))) {
assert(b->bh.prevfree == 0);
assert(BH((char *) b + b->bh.bsize)->bsize == ESent);
assert(BH((char *) b + b->bh.bsize)->prevfree == b->bh.bsize);
/* Unlink the buffer from the free list */
b->ql.blink->ql.flink = b->ql.flink;
b->ql.flink->ql.blink = b->ql.blink;
poolset->relfcn(b);
#ifdef BufStats
poolset->numprel++; /* Nr of expansion block releases */
poolset->numpblk--; /* Total number of blocks */
assert(numpblk == numpget - numprel);
#endif /* BufStats */
}
#endif /* BECtl */
tag_asan_free(buf, bs);
}
#ifdef BECtl
/* BECTL -- Establish automatic pool expansion control */
void bectl(compact, acquire, release, pool_incr, poolset)
int (*compact) _((bufsize sizereq, int sequence));
void *(*acquire) _((bufsize size));
void (*release) _((void *buf));
bufsize pool_incr;
struct bpoolset *poolset;
{
poolset->compfcn = compact;
poolset->acqfcn = acquire;
poolset->relfcn = release;
poolset->exp_incr = pool_incr;
}
#endif
/* BPOOL -- Add a region of memory to the buffer pool. */
void bpool(buf, len, poolset)
void *buf;
bufsize len;
struct bpoolset *poolset;
{
struct bfhead *b = BFH(buf);
struct bhead *bn;
#ifdef SizeQuant
len &= ~(SizeQuant - 1);
#endif
#ifdef BECtl
if (poolset->pool_len == 0) {
pool_len = len;
} else if (len != poolset->pool_len) {
poolset->pool_len = -1;
}
#ifdef BufStats
poolset->numpget++; /* Number of block acquisitions */
poolset->numpblk++; /* Number of blocks total */
assert(poolset->numpblk == poolset->numpget - poolset->numprel);
#endif /* BufStats */
#endif /* BECtl */
/* Since the block is initially occupied by a single free buffer,
it had better not be (much) larger than the largest buffer
whose size we can store in bhead.bsize. */
assert(len - sizeof(struct bhead) <= -((bufsize) ESent + 1));
/* Clear the backpointer at the start of the block to indicate that
there is no free block prior to this one. That blocks
recombination when the first block in memory is released. */
b->bh.prevfree = 0;
/* Chain the new block to the free list. */
assert(poolset->freelist.ql.blink->ql.flink == &poolset->freelist);
assert(poolset->freelist.ql.flink->ql.blink == &poolset->freelist);
b->ql.flink = &poolset->freelist;
b->ql.blink = poolset->freelist.ql.blink;
poolset->freelist.ql.blink = b;
b->ql.blink->ql.flink = b;
/* Create a dummy allocated buffer at the end of the pool. This dummy
buffer is seen when a buffer at the end of the pool is released and
blocks recombination of the last buffer with the dummy buffer at
the end. The length in the dummy buffer is set to the largest
negative number to denote the end of the pool for diagnostic
routines (this specific value is not counted on by the actual
allocation and release functions). */
len -= sizeof(struct bhead);
b->bh.bsize = (bufsize) len;
#ifdef FreeWipe
V memset_unchecked(((char *) b) + sizeof(struct bfhead), 0x55,
(MemSize) (len - sizeof(struct bfhead)));
#endif
bn = BH(((char *) b) + len);
bn->prevfree = (bufsize) len;
/* Definition of ESent assumes two's complement! */
assert((~0) == -1);
bn->bsize = ESent;
}
#ifdef BufStats
/* BSTATS -- Return buffer allocation free space statistics. */
void bstats(curalloc, totfree, maxfree, nget, nrel, poolset)
bufsize *curalloc, *totfree, *maxfree;
long *nget, *nrel;
struct bpoolset *poolset;
{
struct bfhead *b = poolset->freelist.ql.flink;
*nget = poolset->numget;
*nrel = poolset->numrel;
*curalloc = poolset->totalloc;
*totfree = 0;
*maxfree = -1;
while (b != &poolset->freelist) {
assert(b->bh.bsize > 0);
*totfree += b->bh.bsize;
if (b->bh.bsize > *maxfree) {
*maxfree = b->bh.bsize;
}
b = b->ql.flink; /* Link to next buffer */
}
}
#ifdef BECtl
/* BSTATSE -- Return extended statistics */
void bstatse(pool_incr, npool, npget, nprel, ndget, ndrel, poolset)
bufsize *pool_incr;
long *npool, *npget, *nprel, *ndget, *ndrel;
struct bpoolset *poolset;
{
*pool_incr = (poolset->pool_len < 0) ?
-poolset->exp_incr : poolset->exp_incr;
*npool = poolset->numpblk;
*npget = poolset->numpget;
*nprel = poolset->numprel;
*ndget = poolset->numdget;
*ndrel = poolset->numdrel;
}
#endif /* BECtl */
#endif /* BufStats */
#ifdef DumpData
/* BUFDUMP -- Dump the data in a buffer. This is called with the user
data pointer, and backs up to the buffer header. It will
dump either a free block or an allocated one. */
void bufdump(buf)
void *buf;
{
struct bfhead *b;
unsigned char *bdump;
bufsize bdlen;
b = BFH(((char *) buf) - sizeof(struct bhead));
assert(b->bh.bsize != 0);
if (b->bh.bsize < 0) {
bdump = (unsigned char *) buf;
bdlen = (-b->bh.bsize) - sizeof(struct bhead);
} else {
bdump = (unsigned char *) (((char *) b) + sizeof(struct bfhead));
bdlen = b->bh.bsize - sizeof(struct bfhead);
}
while (bdlen > 0) {
int i, dupes = 0;
bufsize l = bdlen;
char bhex[50], bascii[20];
if (l > 16) {
l = 16;
}
for (i = 0; i < l; i++) {
V snprintf(bhex + i * 3, sizeof(bhex) - i * 3, "%02X ",
bdump[i]);
bascii[i] = isprint(bdump[i]) ? bdump[i] : ' ';
}
bascii[i] = 0;
V printf("%-48s %s\n", bhex, bascii);
bdump += l;
bdlen -= l;
while ((bdlen > 16) && (memcmp((char *) (bdump - 16),
(char *) bdump, 16) == 0)) {
dupes++;
bdump += 16;
bdlen -= 16;
}
if (dupes > 1) {
V printf(
" (%d lines [%d bytes] identical to above line skipped)\n",
dupes, dupes * 16);
} else if (dupes == 1) {
bdump -= 16;
bdlen += 16;
}
}
}
#endif
#ifdef BufDump
/* BPOOLD -- Dump a buffer pool. The buffer headers are always listed.
If DUMPALLOC is nonzero, the contents of allocated buffers
are dumped. If DUMPFREE is nonzero, free blocks are
dumped as well. If FreeWipe checking is enabled, free
blocks which have been clobbered will always be dumped. */
void bpoold(buf, dumpalloc, dumpfree)
void *buf;
int dumpalloc, dumpfree;
{
struct bfhead *b = BFH(buf);
while (b->bh.bsize != ESent) {
bufsize bs = b->bh.bsize;
if (bs < 0) {
bs = -bs;
V printf("Allocated buffer: size %6ld bytes.\n", (long) bs);
if (dumpalloc) {
bufdump((void *) (((char *) b) + sizeof(struct bhead)));
}
} else {
char *lerr = "";
assert(bs > 0);
if ((b->ql.blink->ql.flink != b) ||
(b->ql.flink->ql.blink != b)) {
lerr = " (Bad free list links)";
}
V printf("Free block: size %6ld bytes.%s\n",
(long) bs, lerr);
#ifdef FreeWipe
lerr = ((char *) b) + sizeof(struct bfhead);
if ((bs > sizeof(struct bfhead)) && ((*lerr != 0x55) ||
(memcmp(lerr, lerr + 1,
(MemSize) (bs - (sizeof(struct bfhead) + 1))) != 0))) {
V printf(
"(Contents of above free block have been overstored.)\n");
bufdump((void *) (((char *) b) + sizeof(struct bhead)));
} else
#endif
if (dumpfree) {
bufdump((void *) (((char *) b) + sizeof(struct bhead)));
}
}
b = BFH(((char *) b) + bs);
}
}
#endif /* BufDump */
#ifdef BufValid
/* BPOOLV -- Validate a buffer pool. If NDEBUG isn't defined,
any error generates an assertion failure. */
int bpoolv(buf)
void *buf;
{
struct bfhead *b = BFH(buf);
while (b->bh.bsize != ESent) {
bufsize bs = b->bh.bsize;
if (bs < 0) {
bs = -bs;
} else {
const char *lerr = "";
assert(bs > 0);
if (bs <= 0) {
return 0;
}
if ((b->ql.blink->ql.flink != b) ||
(b->ql.flink->ql.blink != b)) {
V printf("Free block: size %6ld bytes. (Bad free list links)\n",
(long) bs);
assert(0);
return 0;
}
#ifdef FreeWipe
lerr = ((char *) b) + sizeof(struct bfhead);
if ((bs > sizeof(struct bfhead)) && ((*lerr != 0x55) ||
(memcmp(lerr, lerr + 1,
(MemSize) (bs - (sizeof(struct bfhead) + 1))) != 0))) {
V printf(
"(Contents of above free block have been overstored.)\n");
bufdump((void *) (((char *) b) + sizeof(struct bhead)));
assert(0);
return 0;
}
#endif
}
b = BFH(((char *) b) + bs);
}
return 1;
}
#endif /* BufValid */
/***********************\
* *
* Built-in test program *
* *
\***********************/
#if !defined(__KERNEL__) && !defined(__LDELF__) && defined(CFG_TA_BGET_TEST)
#define TestProg 20000
#ifdef BECtl
#define PoolSize 300000 /* Test buffer pool size */
#else
#define PoolSize 50000 /* Test buffer pool size */
#endif
#define ExpIncr 32768 /* Test expansion block size */
#define CompactTries 10 /* Maximum tries at compacting */
#define dumpAlloc 0 /* Dump allocated buffers ? */
#define dumpFree 0 /* Dump free buffers ? */
static char *bchain = NULL; /* Our private buffer chain */
static char *bp = NULL; /* Our initial buffer pool */
#ifdef UsingFloat
#include <math.h>
#endif
static unsigned long int next = 1;
static void *(*mymalloc)(size_t size);
static void (*myfree)(void *ptr);
static struct bpoolset mypoolset = {
.freelist = {
.bh = { 0, 0},
.ql = { &mypoolset.freelist, &mypoolset.freelist},
}
};
/* Return next random integer */
static int myrand(void)
{
next = next * 1103515245L + 12345;
return (unsigned int) (next / 65536L) % 32768L;
}
/* Set seed for random generator */
static void mysrand(unsigned int seed)
{
next = seed;
}
/* STATS -- Edit statistics returned by bstats() or bstatse(). */
static void stats(const char *when __maybe_unused,
struct bpoolset *poolset __maybe_unused)
{
#ifdef BufStats
bufsize cural, totfree, maxfree;
long nget, nfree;
#endif
#ifdef BECtl
bufsize pincr;
long totblocks, npget, nprel, ndget, ndrel;
#endif
#ifdef BufStats
bstats(&cural, &totfree, &maxfree, &nget, &nfree, poolset);
V printf(
"%s: %ld gets, %ld releases. %ld in use, %ld free, largest = %ld\n",
when, nget, nfree, (long) cural, (long) totfree, (long) maxfree);
#endif
#ifdef BECtl
bstatse(&pincr, &totblocks, &npget, &nprel, &ndget, &ndrel, poolset);
V printf(
" Blocks: size = %ld, %ld (%ld bytes) in use, %ld gets, %ld frees\n",
(long)pincr, totblocks, pincr * totblocks, npget, nprel);
V printf(" %ld direct gets, %ld direct frees\n", ndget, ndrel);
#endif /* BECtl */
}
#ifdef BECtl
static int protect = 0; /* Disable compaction during bgetr() */
/* BCOMPACT -- Compaction call-back function. */
static int bcompact(bsize, seq)
bufsize bsize;
int seq;
{
#ifdef CompactTries
char *bc = bchain;
int i = rand() & 0x3;
#ifdef COMPACTRACE
V printf("Compaction requested. %ld bytes needed, sequence %d.\n",
(long) bsize, seq);
#endif
if (protect || (seq > CompactTries)) {
#ifdef COMPACTRACE
V printf("Compaction gave up.\n");
#endif
return 0;
}
/* Based on a random cast, release a random buffer in the list
of allocated buffers. */
while (i > 0 && bc != NULL) {
bc = *((char **) bc);
i--;
}
if (bc != NULL) {
char *fb;
fb = *((char **) bc);
if (fb != NULL) {
*((char **) bc) = *((char **) fb);
brel((void *) fb);
return 1;
}
}
#ifdef COMPACTRACE
V printf("Compaction bailed out.\n");
#endif
#endif /* CompactTries */
return 0;
}
/* BEXPAND -- Expand pool call-back function. */
static void *bexpand(size)
bufsize size;
{
void *np = NULL;
bufsize cural, totfree, maxfree;
long nget, nfree;
/* Don't expand beyond the total allocated size given by PoolSize. */
bstats(&cural, &totfree, &maxfree, &nget, &nfree);
if (cural < PoolSize) {
np = (void *) mymalloc((unsigned) size);
}
#ifdef EXPTRACE
V printf("Expand pool by %ld -- %s.\n", (long) size,
np == NULL ? "failed" : "succeeded");
#endif
return np;
}
/* BSHRINK -- Shrink buffer pool call-back function. */
static void bshrink(buf)
void *buf;
{
if (((char *) buf) == bp) {
#ifdef EXPTRACE
V printf("Initial pool released.\n");
#endif
bp = NULL;
}
#ifdef EXPTRACE
V printf("Shrink pool.\n");
#endif
myfree((char *) buf);
}
#endif /* BECtl */
/* Restrict buffer requests to those large enough to contain our pointer and
small enough for the CPU architecture. */
static bufsize blimit(bufsize bs)
{
if (bs < sizeof(char *)) {
bs = sizeof(char *);
}
/* This is written out in this ugly fashion because the
cool expression in sizeof(int) that auto-configured
to any length int befuddled some compilers. */
if (sizeof(int) == 2) {
if (bs > 32767) {
bs = 32767;
}
} else {
if (bs > 200000) {
bs = 200000;
}
}
return bs;
}
int bget_main_test(void *(*malloc_func)(size_t), void (*free_func)(void *))
{
int i;
#ifdef UsingFloat
double x;
#endif
mymalloc = malloc_func;
myfree = free_func;
/* Seed the random number generator. If Repeatable is defined, we
always use the same seed. Otherwise, we seed from the clock to
shake things up from run to run. */
mysrand(1234);
/* Compute x such that pow(x, p) ranges between 1 and 4*ExpIncr as
p ranges from 0 to ExpIncr-1, with a concentration in the lower
numbers. */
#ifdef UsingFloat
x = 4.0 * ExpIncr;
x = log(x);
x = exp(log(4.0 * ExpIncr) / (ExpIncr - 1.0));
#endif
#ifdef BECtl
bectl(bcompact, bexpand, bshrink, (bufsize) ExpIncr, &mypoolset);
bp = mymalloc(ExpIncr);
assert(bp != NULL);
bpool((void *) bp, (bufsize) ExpIncr);
#else
bp = mymalloc(PoolSize);
assert(bp != NULL);
bpool((void *) bp, (bufsize) PoolSize, &mypoolset);
#endif
stats("Create pool", &mypoolset);
#ifdef BufValid
V bpoolv((void *) bp);
#endif
#ifdef BufDump
bpoold((void *) bp, dumpAlloc, dumpFree);
#endif
for (i = 0; i < TestProg; i++) {
char *cb;
#ifdef UsingFloat
bufsize bs = pow(x, (double) (myrand() & (ExpIncr - 1)));
#else
bufsize bs = (rand() & (ExpIncr * 4 - 1)) / (1 << (rand() & 0x7));
#endif
assert(bs <= (((bufsize) 4) * ExpIncr));
bs = blimit(bs);
if (myrand() & 0x400) {
cb = (char *) bgetz(bs, &mypoolset);
} else {
cb = (char *) bget(bs, &mypoolset);
}
if (cb == NULL) {
#ifdef EasyOut
break;
#else
char *bc = bchain;
if (bc != NULL) {
char *fb;
fb = *((char **) bc);
if (fb != NULL) {
*((char **) bc) = *((char **) fb);
brel((void *) fb, &mypoolset, true/*wipe*/);
}
continue;
}
#endif
}
*((char **) cb) = (char *) bchain;
bchain = cb;
/* Based on a random cast, release a random buffer in the list
of allocated buffers. */
if ((myrand() & 0x10) == 0) {
char *bc = bchain;
int j = myrand() & 0x3;
while (j > 0 && bc != NULL) {
bc = *((char **) bc);
j--;
}
if (bc != NULL) {
char *fb;
fb = *((char **) bc);
if (fb != NULL) {
*((char **) bc) = *((char **) fb);
brel((void *) fb, &mypoolset, true/*wipe*/);
}
}
}
/* Based on a random cast, reallocate a random buffer in the list
to a random size */
if ((myrand() & 0x20) == 0) {
char *bc = bchain;
int j = myrand() & 0x3;
while (j > 0 && bc != NULL) {
bc = *((char **) bc);
j--;
}
if (bc != NULL) {
char *fb;
fb = *((char **) bc);
if (fb != NULL) {
char *newb;
#ifdef UsingFloat
bs = pow(x, (double) (myrand() & (ExpIncr - 1)));
#else
bs = (rand() & (ExpIncr * 4 - 1)) / (1 << (rand() & 0x7));
#endif
bs = blimit(bs);
#ifdef BECtl
protect = 1; /* Protect against compaction */
#endif
newb = (char *) bgetr((void *) fb, bs, &mypoolset);
#ifdef BECtl
protect = 0;
#endif
if (newb != NULL) {
*((char **) bc) = newb;
}
}
}
}
}
stats("\nAfter allocation", &mypoolset);
if (bp != NULL) {
#ifdef BufValid
V bpoolv((void *) bp);
#endif
#ifdef BufDump
bpoold((void *) bp, dumpAlloc, dumpFree);
#endif
}
while (bchain != NULL) {
char *buf = bchain;
bchain = *((char **) buf);
brel((void *) buf, &mypoolset, true/*wipe*/);
}
stats("\nAfter release", &mypoolset);
#ifndef BECtl
if (bp != NULL) {
#ifdef BufValid
V bpoolv((void *) bp);
#endif
#ifdef BufDump
bpoold((void *) bp, dumpAlloc, dumpFree);
#endif
}
#endif
return 0;
}
#endif
|