aboutsummaryrefslogtreecommitdiffstats
path: root/subversion/libsvn_subr/config_file.c
blob: 9c0a83a170f8be30d8442082d6572a2872eaacf6 (plain) (blame)
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
/*
 * config_file.c :  parsing configuration files
 *
 * ====================================================================
 *    Licensed to the Apache Software Foundation (ASF) under one
 *    or more contributor license agreements.  See the NOTICE file
 *    distributed with this work for additional information
 *    regarding copyright ownership.  The ASF licenses this file
 *    to you under the Apache License, Version 2.0 (the
 *    "License"); you may not use this file except in compliance
 *    with the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing,
 *    software distributed under the License is distributed on an
 *    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *    KIND, either express or implied.  See the License for the
 *    specific language governing permissions and limitations
 *    under the License.
 * ====================================================================
 */



#include <apr_lib.h>
#include <apr_env.h>
#include <apr_tables.h>

#include "config_impl.h"
#include "svn_io.h"
#include "svn_types.h"
#include "svn_dirent_uri.h"
#include "svn_auth.h"
#include "svn_hash.h"
#include "svn_subst.h"
#include "svn_utf.h"
#include "svn_pools.h"
#include "svn_user.h"
#include "svn_ctype.h"

#include "private/svn_config_private.h"
#include "private/svn_subr_private.h"
#include "svn_private_config.h"

#ifdef __HAIKU__
#  include <FindDirectory.h>
#  include <StorageDefs.h>
#endif

/* Used to terminate lines in large multi-line string literals. */
#define NL APR_EOL_STR


/* File parsing context */
typedef struct parse_context_t
{
  /* The configuration constructor. */
  svn_config__constructor_t *constructor;
  void *constructor_baton;

  /* The stream struct */
  svn_stream_t *stream;

  /* The current line in the file */
  int line;

  /* Emulate an ungetc */
  int ungotten_char;

  /* We're currently parsing a section */
  svn_boolean_t in_section;

  /* Temporary strings */
  svn_stringbuf_t *section;
  svn_stringbuf_t *option;
  svn_stringbuf_t *value;
  svn_stringbuf_t *line_read;

  /* Parser buffer for getc() to avoid call overhead into several libraries
     for every character */
  char parser_buffer[SVN__STREAM_CHUNK_SIZE]; /* Larger than most config files */
  size_t buffer_pos; /* Current position within parser_buffer */
  size_t buffer_size; /* parser_buffer contains this many bytes */

  /* Non-zero if we hit EOF on the stream. */
  svn_boolean_t hit_stream_eof;
} parse_context_t;


/* Config representation constructor */
struct svn_config__constructor_t
{
  /* Constructor callbacks; see docs for svn_config__constructor_create. */
  svn_config__open_section_fn open_section;
  svn_config__close_section_fn close_section;
  svn_config__add_value_fn add_value;
};

svn_config__constructor_t *
svn_config__constructor_create(
    svn_config__open_section_fn open_section_callback,
    svn_config__close_section_fn close_section_callback,
    svn_config__add_value_fn add_value_callback,
    apr_pool_t *result_pool)
{
  svn_config__constructor_t *ctor = apr_palloc(result_pool, sizeof(*ctor));
  ctor->open_section = open_section_callback;
  ctor->close_section = close_section_callback;
  ctor->add_value = add_value_callback;
  return ctor;
}

/* Called after we've parsed a section name and before we start
   parsing any options within that section. */
static APR_INLINE svn_error_t *
open_section(parse_context_t *ctx, svn_boolean_t *stop)
{
  if (ctx->constructor->open_section)
    {
      svn_error_t *err = ctx->constructor->open_section(
          ctx->constructor_baton, ctx->section);
      if (err)
        {
          if (err->apr_err == SVN_ERR_CEASE_INVOCATION)
            {
              *stop = TRUE;
              svn_error_clear(err);
              return SVN_NO_ERROR;
            }
          else
            return svn_error_trace(err);
        }
    }

  *stop = FALSE;
  ctx->in_section = TRUE;
  return SVN_NO_ERROR;
}

/* Called after we've parsed all options within a section and before
   we start parsing the next section. */
static APR_INLINE svn_error_t *
close_section(parse_context_t *ctx, svn_boolean_t *stop)
{
  ctx->in_section = FALSE;
  if (ctx->constructor->close_section)
    {
      svn_error_t *err = ctx->constructor->close_section(
          ctx->constructor_baton, ctx->section);
      if (err)
        {
          if (err->apr_err == SVN_ERR_CEASE_INVOCATION)
            {
              *stop = TRUE;
              svn_error_clear(err);
              return SVN_NO_ERROR;
            }
          else
            return svn_error_trace(err);
        }
    }

  *stop = FALSE;
  return SVN_NO_ERROR;
}

/* Called every tyme we've parsed a complete (option, value) pair. */
static APR_INLINE svn_error_t *
add_value(parse_context_t *ctx, svn_boolean_t *stop)
{
  if (ctx->constructor->add_value)
    {
      svn_error_t *err =  ctx->constructor->add_value(
          ctx->constructor_baton, ctx->section,
          ctx->option, ctx->value);
      if (err)
        {
          if (err->apr_err == SVN_ERR_CEASE_INVOCATION)
            {
              *stop = TRUE;
              svn_error_clear(err);
              return SVN_NO_ERROR;
            }
          else
            return svn_error_trace(err);
        }
    }

  *stop = FALSE;
  return SVN_NO_ERROR;
}


/* Emulate getc() because streams don't support it.
 *
 * In order to be able to ungetc(), use the CXT instead of the stream
 * to be able to store the 'ungotton' character.
 *
 */
static APR_INLINE svn_error_t *
parser_getc(parse_context_t *ctx, int *c)
{
  do
    {
      if (ctx->ungotten_char != EOF)
        {
          *c = ctx->ungotten_char;
          ctx->ungotten_char = EOF;
        }
      else if (ctx->buffer_pos < ctx->buffer_size)
        {
          *c = (unsigned char)ctx->parser_buffer[ctx->buffer_pos];
          ctx->buffer_pos++;
        }
      else
        {
          if (!ctx->hit_stream_eof)
            {
              ctx->buffer_pos = 0;
              ctx->buffer_size = sizeof(ctx->parser_buffer);

              SVN_ERR(svn_stream_read_full(ctx->stream, ctx->parser_buffer,
                                           &(ctx->buffer_size)));
              ctx->hit_stream_eof = (ctx->buffer_size != sizeof(ctx->parser_buffer));
            }

          if (ctx->buffer_pos < ctx->buffer_size)
            {
              *c = (unsigned char)ctx->parser_buffer[ctx->buffer_pos];
              ctx->buffer_pos++;
            }
          else
            *c = EOF;
        }
    }
  while (*c == '\r');

  return SVN_NO_ERROR;
}

/* Simplified version of parser_getc() to be used inside skipping loops.
 * It will not check for 'ungotton' chars and may or may not ignore '\r'.
 *
 * In a 'while(cond) getc();' loop, the first iteration must call
 * parser_getc to handle all the special cases.  Later iterations should
 * use parser_getc_plain for maximum performance.
 */
static APR_INLINE svn_error_t *
parser_getc_plain(parse_context_t *ctx, int *c)
{
  if (ctx->buffer_pos < ctx->buffer_size)
    {
      *c = (unsigned char)ctx->parser_buffer[ctx->buffer_pos];
      ctx->buffer_pos++;

      return SVN_NO_ERROR;
    }

  return parser_getc(ctx, c);
}

/* Emulate ungetc() because streams don't support it.
 *
 * Use CTX to store the ungotten character C.
 */
static APR_INLINE svn_error_t *
parser_ungetc(parse_context_t *ctx, int c)
{
  ctx->ungotten_char = c;

  return SVN_NO_ERROR;
}

/* Read from CTX to the end of the line (or file) and write the data
   into LINE.  Previous contents of *LINE will be overwritten.
   Returns the char that ended the line in *C; the char is either
   EOF or newline. */
static svn_error_t *
parser_get_line(parse_context_t *ctx, svn_stringbuf_t *line, int *c)
{
  int ch;
  svn_stringbuf_setempty(line);

  /* Loop until EOF of newline. There is one extra iteration per
   * parser buffer refill.  The initial parser_getc() also ensures
   * that the unget buffer is emptied. */
  SVN_ERR(parser_getc(ctx, &ch));
  while (ch != '\n' && ch != EOF)
    {
      const char *start, *newline;

      /* Save the char we just read. */
      svn_stringbuf_appendbyte(line, ch);

      /* Scan the parser buffer for NL. */
      start = ctx->parser_buffer + ctx->buffer_pos;
      newline = memchr(start, '\n', ctx->buffer_size - ctx->buffer_pos);
      if (newline)
        {
          /* NL found before the end of the of the buffer. */
          svn_stringbuf_appendbytes(line, start, newline - start);
          ch = '\n';
          ctx->buffer_pos = newline - ctx->parser_buffer + 1;
          break;
        }
      else
        {
          /* Hit the end of the buffer.  This may be either due to
           * buffer size or EOF.  In any case, all (remaining) current
           * buffer data is part of the line to read. */
          const char *end = ctx->parser_buffer + ctx->buffer_size;
          ctx->buffer_pos = ctx->buffer_size;

          svn_stringbuf_appendbytes(line, start, end - start);
        }

      /* refill buffer, check for EOF */
      SVN_ERR(parser_getc_plain(ctx, &ch));
    }

  *c = ch;
  return SVN_NO_ERROR;
}

/* Eat chars from STREAM until encounter non-whitespace, newline, or EOF.
   Set *PCOUNT to the number of characters eaten, not counting the
   last one, and return the last char read (the one that caused the
   break).  */
static APR_INLINE svn_error_t *
skip_whitespace(parse_context_t *ctx, int *c, int *pcount)
{
  int ch = 0;
  int count = 0;

  SVN_ERR(parser_getc(ctx, &ch));
  while (svn_ctype_isspace(ch) && ch != '\n' && ch != EOF)
    {
      ++count;
      SVN_ERR(parser_getc_plain(ctx, &ch));
    }
  *pcount = count;
  *c = ch;
  return SVN_NO_ERROR;
}


/* Skip to the end of the line (or file).  Returns the char that ended
   the line; the char is either EOF or newline. */
static APR_INLINE svn_error_t *
skip_to_eoln(parse_context_t *ctx, int *c)
{
  int ch;

  SVN_ERR(parser_getc(ctx, &ch));
  while (ch != '\n' && ch != EOF)
    {
      /* This is much faster than checking individual bytes.
       * We use this function a lot when skipping comment lines.
       *
       * This assumes that the ungetc buffer is empty, but that is a
       * safe assumption right after reading a character (which would
       * clear the buffer. */
      const char *newline = memchr(ctx->parser_buffer + ctx->buffer_pos, '\n',
                                   ctx->buffer_size - ctx->buffer_pos);
      if (newline)
        {
          ch = '\n';
          ctx->buffer_pos = newline - ctx->parser_buffer + 1;
          break;
        }

      /* refill buffer, check for EOF */
      SVN_ERR(parser_getc_plain(ctx, &ch));
    }

  *c = ch;
  return SVN_NO_ERROR;
}

/* Skip a UTF-8 Byte Order Mark if found. */
static APR_INLINE svn_error_t *
skip_bom(parse_context_t *ctx)
{
  int ch;

  SVN_ERR(parser_getc(ctx, &ch));
  if (ch == 0xEF)
    {
      const unsigned char *buf = (unsigned char *)ctx->parser_buffer;
      /* This makes assumptions about the implementation of parser_getc and
       * the use of skip_bom.  Specifically that parser_getc() will get all
       * of the BOM characters into the parse_context_t buffer.  This can
       * safely be assumed as long as we only try to use skip_bom() at the
       * start of the stream and the buffer is longer than 3 characters. */
      SVN_ERR_ASSERT(ctx->buffer_size > ctx->buffer_pos + 1 ||
                     ctx->hit_stream_eof);
      if (ctx->buffer_size > ctx->buffer_pos + 1 &&
          buf[ctx->buffer_pos] == 0xBB && buf[ctx->buffer_pos + 1] == 0xBF)
        ctx->buffer_pos += 2;
      else
        SVN_ERR(parser_ungetc(ctx, ch));
    }
  else
    SVN_ERR(parser_ungetc(ctx, ch));

  return SVN_NO_ERROR;
}

/* Parse continuation lines of single option value if they exist.  Append
 * their contents, including *PCH, to CTX->VALUE.  Return the first char
 * of the next line or EOF in *PCH. */
static svn_error_t *
parse_value_continuation_lines(int *pch, parse_context_t *ctx)
{
  svn_boolean_t end_of_val = FALSE;
  svn_boolean_t stop;
  int ch = *pch;

  /* Leading and trailing whitespace is ignored. */
  svn_stringbuf_strip_whitespace(ctx->value);

  /* Look for any continuation lines. */
  for (;;)
    {

      if (ch == EOF || end_of_val)
        {
          /* At end of file. The value is complete, there can't be
             any continuation lines. */
          SVN_ERR(add_value(ctx, &stop));
          if (stop)
            return SVN_NO_ERROR;
          break;
        }
      else
        {
          int count;
          ++ctx->line;
          SVN_ERR(skip_whitespace(ctx, &ch, &count));

          switch (ch)
            {
            case '\n':
              /* The next line was empty. Ergo, it can't be a
                 continuation line. */
              ++ctx->line;
              end_of_val = TRUE;
              continue;

            case EOF:
              /* This is also an empty line. */
              end_of_val = TRUE;
              continue;

            default:
              if (count == 0)
                {
                  /* This line starts in the first column.  That means
                     it's either a section, option or comment.  Put
                     the char back into the stream, because it doesn't
                     belong to us. */
                  SVN_ERR(parser_ungetc(ctx, ch));
                  end_of_val = TRUE;
                }
              else
                {
                  /* This is a continuation line. Read it. */
                  SVN_ERR(parser_ungetc(ctx, ch));
                  SVN_ERR(parser_get_line(ctx, ctx->line_read, &ch));

                  /* Trailing whitespace is ignored. */
                  svn_stringbuf_strip_whitespace(ctx->line_read);

                  svn_stringbuf_appendbyte(ctx->value, ' ');
                  svn_stringbuf_appendbytes(ctx->value, ctx->line_read->data,
                                            ctx->line_read->len);
                }
            }
        }
    }

  *pch = ch;
  return SVN_NO_ERROR;
}


/* Parse a single option */
static svn_error_t *
parse_option(int *pch, parse_context_t *ctx, apr_pool_t *scratch_pool)
{
  svn_error_t *err = SVN_NO_ERROR;
  int ch;
  char *equals, *separator;

  /* Read the first line. */
  parser_ungetc(ctx, *pch); /* Yes, the first char is relevant. */
  SVN_ERR(parser_get_line(ctx, ctx->line_read, &ch));

  /* Extract the option name from it. */
  equals = strchr(ctx->line_read->data, '=');
  if (equals)
    {
      /* Efficiently look for a colon separator prior to the equals sign.
       * Since there is no strnchr, we limit the search by temporarily
       * limiting the string. */
      char *colon;
      *equals = 0;
      colon = strchr(ctx->line_read->data, ':');
      *equals = '=';

      separator = colon ? colon : equals;
    }
  else
    {
      /* No '=' separator so far.  Look for colon. */
      separator = strchr(ctx->line_read->data, ':');
    }

  if (!separator)
    {
      ch = EOF;
      err = svn_error_createf(SVN_ERR_MALFORMED_FILE, NULL,
                              _("line %d: Option must end with ':' or '='"),
                              ctx->line);
    }
  else
    {
      /* Whitespace around the name separator is ignored. */
      const char *end = separator;
      while (svn_ctype_isspace(*--end))
        ;
      while (svn_ctype_isspace(*++separator))
        ;

      /* Extract the option.  It can't contain whitespace chars. */
      svn_stringbuf_setempty(ctx->option);
      svn_stringbuf_appendbytes(ctx->option, ctx->line_read->data,
                                end + 1 - ctx->line_read->data);

      /* Extract the first line of the value. */
      end = ctx->line_read->data + ctx->line_read->len;
      svn_stringbuf_setempty(ctx->value);
      svn_stringbuf_appendbytes(ctx->value, separator, end - separator);
      err = parse_value_continuation_lines(&ch, ctx);
    }

  *pch = ch;
  return err;
}


/* Read chars until enounter ']', then skip everything to the end of
 * the line.  Set *PCH to the character that ended the line (either
 * newline or EOF), and set CTX->section to the string of characters
 * seen before ']'.
 *
 * This is meant to be called immediately after reading the '[' that
 * starts a section name.
 */
static svn_error_t *
parse_section_name(int *pch, parse_context_t *ctx,
                   apr_pool_t *scratch_pool)
{
  svn_error_t *err = SVN_NO_ERROR;
  int ch;
  char *terminal;

  SVN_ERR(parser_get_line(ctx, ctx->section, &ch));
  terminal = strchr(ctx->section->data, ']');

  if (!terminal)
    {
      ch = EOF;
      err = svn_error_createf(SVN_ERR_MALFORMED_FILE, NULL,
                              _("line %d: Section header must end with ']'"),
                              ctx->line);
    }
  else
    {
      /* Everything from the ']' to the end of the line is ignored. */
      *terminal = 0;
      ctx->section->len = terminal - ctx->section->data;
    }

  *pch = ch;
  return err;
}


svn_error_t *
svn_config__sys_config_path(const char **path_p,
                            const char *fname,
                            apr_pool_t *pool)
{
  *path_p = NULL;

  /* Note that even if fname is null, svn_dirent_join_many will DTRT. */

#ifdef WIN32
  {
    const char *folder;
    SVN_ERR(svn_config__win_config_path(&folder, TRUE, pool, pool));
    *path_p = svn_dirent_join_many(pool, folder,
                                   SVN_CONFIG__SUBDIRECTORY, fname,
                                   SVN_VA_NULL);
  }

#elif defined(__HAIKU__)
  {
    char folder[B_PATH_NAME_LENGTH];

    status_t error = find_directory(B_COMMON_SETTINGS_DIRECTORY, -1, false,
                                    folder, sizeof(folder));
    if (error)
      return SVN_NO_ERROR;

    *path_p = svn_dirent_join_many(pool, folder,
                                   SVN_CONFIG__SYS_DIRECTORY, fname,
                                   SVN_VA_NULL);
  }
#else  /* ! WIN32 && !__HAIKU__ */

  *path_p = svn_dirent_join_many(pool, SVN_CONFIG__SYS_DIRECTORY, fname,
                                 SVN_VA_NULL);

#endif /* WIN32 */

  return SVN_NO_ERROR;
}

/* Callback for svn_config_enumerate2: Continue to next value. */
static svn_boolean_t
expand_value(const char *name,
             const char *value,
             void *baton,
             apr_pool_t *pool)
{
  return TRUE;
}

/* Callback for svn_config_enumerate_sections2:
 * Enumerate and implicitly expand all values in this section.
 */
static svn_boolean_t
expand_values_in_section(const char *name,
                         void *baton,
                         apr_pool_t *pool)
{
  svn_config_t *cfg = baton;
  svn_config_enumerate2(cfg, name, expand_value, NULL, pool);

  return TRUE;
}


/*** Exported interfaces. ***/

void
svn_config__set_read_only(svn_config_t *cfg,
                          apr_pool_t *scratch_pool)
{
  /* expand all items such that later calls to getters won't need to
   * change internal state */
  svn_config_enumerate_sections2(cfg, expand_values_in_section,
                                 cfg, scratch_pool);

  /* now, any modification attempt will be ignored / trigger an assertion
   * in debug mode */
  cfg->read_only = TRUE;
}

svn_boolean_t
svn_config__is_read_only(svn_config_t *cfg)
{
  return cfg->read_only;
}

svn_config_t *
svn_config__shallow_copy(svn_config_t *src,
                         apr_pool_t *pool)
{
  svn_config_t *cfg = apr_palloc(pool, sizeof(*cfg));

  cfg->sections = src->sections;
  cfg->pool = pool;

  /* r/o configs are fully expanded and don't need the x_pool anymore */
  cfg->x_pool = src->read_only ? NULL : svn_pool_create(pool);
  cfg->x_values = src->x_values;
  cfg->tmp_key = svn_stringbuf_create_empty(pool);
  cfg->tmp_value = svn_stringbuf_create_empty(pool);
  cfg->section_names_case_sensitive = src->section_names_case_sensitive;
  cfg->option_names_case_sensitive = src->option_names_case_sensitive;
  cfg->read_only = src->read_only;

  return cfg;
}

void
svn_config__shallow_replace_section(svn_config_t *target,
                                    svn_config_t *source,
                                    const char *section)
{
  if (target->read_only)
    target->sections = apr_hash_copy(target->pool, target->sections);

  svn_hash_sets(target->sections, section,
                svn_hash_gets(source->sections, section));
}



svn_error_t *
svn_config__parse_file(svn_config_t *cfg, const char *file,
                       svn_boolean_t must_exist, apr_pool_t *result_pool)
{
  svn_error_t *err = SVN_NO_ERROR;
  apr_file_t *apr_file;
  svn_stream_t *stream;
  apr_pool_t *scratch_pool = svn_pool_create(result_pool);

  /* Use unbuffered IO since we use our own buffering. */
  err = svn_io_file_open(&apr_file, file, APR_READ, APR_OS_DEFAULT,
                         scratch_pool);

  if (! must_exist && err && APR_STATUS_IS_ENOENT(err->apr_err))
    {
      svn_error_clear(err);
      svn_pool_destroy(scratch_pool);
      return SVN_NO_ERROR;
    }
  else
    SVN_ERR(err);

  stream = svn_stream_from_aprfile2(apr_file, FALSE, scratch_pool);
  err = svn_config__parse_stream(stream,
                                 svn_config__constructor_create(
                                     NULL, NULL,
                                     svn_config__default_add_value_fn,
                                     scratch_pool),
                                 cfg, scratch_pool);

  if (err != SVN_NO_ERROR)
    {
      /* Add the filename to the error stack. */
      err = svn_error_createf(err->apr_err, err,
                              _("Error while parsing config file: %s:"),
                              svn_dirent_local_style(file, scratch_pool));
    }

  /* Close the streams (and other cleanup): */
  svn_pool_destroy(scratch_pool);

  return err;
}

svn_error_t *
svn_config__parse_stream(svn_stream_t *stream,
                         svn_config__constructor_t *constructor,
                         void *constructor_baton,
                         apr_pool_t *scratch_pool)
{
  parse_context_t *ctx;
  svn_boolean_t stop;
  int ch, count;

  ctx = apr_palloc(scratch_pool, sizeof(*ctx));

  ctx->constructor = constructor;
  ctx->constructor_baton = constructor_baton;
  ctx->stream = stream;
  ctx->line = 1;
  ctx->ungotten_char = EOF;
  ctx->in_section = FALSE;
  ctx->section = svn_stringbuf_create_empty(scratch_pool);
  ctx->option = svn_stringbuf_create_empty(scratch_pool);
  ctx->value = svn_stringbuf_create_empty(scratch_pool);
  ctx->line_read = svn_stringbuf_create_empty(scratch_pool);
  ctx->buffer_pos = 0;
  ctx->buffer_size = 0;
  ctx->hit_stream_eof = FALSE;

  SVN_ERR(skip_bom(ctx));

  do
    {
      SVN_ERR(skip_whitespace(ctx, &ch, &count));

      switch (ch)
        {
        case '[':               /* Start of section header */
          if (count != 0)
            return svn_error_createf(SVN_ERR_MALFORMED_FILE, NULL,
                                     _("line %d: Section header"
                                       " must start in the first column"),
                                     ctx->line);

          /* Close the previous section before starting a new one. */
          if (ctx->in_section)
            {
              SVN_ERR(close_section(ctx, &stop));
              if (stop)
                return SVN_NO_ERROR;
            }
          SVN_ERR(parse_section_name(&ch, ctx, scratch_pool));
          SVN_ERR(open_section(ctx, &stop));
          if (stop)
            return SVN_NO_ERROR;
          break;

        case '#':               /* Comment */
          if (count == 0)
            {
              SVN_ERR(skip_to_eoln(ctx, &ch));
              ++(ctx->line);
            }
          else
            return svn_error_createf(SVN_ERR_MALFORMED_FILE, NULL,
                                     _("line %d: Comment"
                                       " must start in the first column"),
                                     ctx->line);
          break;

        case '\n':              /* Empty line */
          ++(ctx->line);
          break;

        case EOF:               /* End of file or read error */
          break;

        default:
          if (svn_stringbuf_isempty(ctx->section))
            return svn_error_createf(SVN_ERR_MALFORMED_FILE, NULL,
                                     _("line %d: Section header expected"),
                                     ctx->line);
          else if (count != 0)
            return svn_error_createf(SVN_ERR_MALFORMED_FILE, NULL,
                                     _("line %d: Option expected"),
                                     ctx->line);
          else
            SVN_ERR(parse_option(&ch, ctx, scratch_pool));
          break;
        }
    }
  while (ch != EOF);

  /* Emit the last close-section call to wrap up. */
  if (ctx->in_section)
    SVN_ERR(close_section(ctx, &stop));
  return SVN_NO_ERROR;
}


/* Helper for ensure_auth_dirs: create SUBDIR under AUTH_DIR, iff
   SUBDIR does not already exist, but ignore any errors.  Use POOL for
   temporary allocation. */
static void
ensure_auth_subdir(const char *auth_dir,
                   const char *subdir,
                   apr_pool_t *pool)
{
  svn_error_t *err;
  const char *subdir_full_path;
  svn_node_kind_t kind;

  subdir_full_path = svn_dirent_join(auth_dir, subdir, pool);
  err = svn_io_check_path(subdir_full_path, &kind, pool);
  if (err || kind == svn_node_none)
    {
      svn_error_clear(err);
      svn_error_clear(svn_io_dir_make(subdir_full_path, APR_OS_DEFAULT, pool));
    }
}

/* Helper for svn_config_ensure:  see if ~/.subversion/auth/ and its
   subdirs exist, try to create them, but don't throw errors on
   failure.  PATH is assumed to be a path to the user's private config
   directory. */
static void
ensure_auth_dirs(const char *path,
                 apr_pool_t *pool)
{
  svn_node_kind_t kind;
  const char *auth_dir;
  svn_error_t *err;

  /* Ensure ~/.subversion/auth/ */
  auth_dir = svn_dirent_join(path, SVN_CONFIG__AUTH_SUBDIR, pool);
  err = svn_io_check_path(auth_dir, &kind, pool);
  if (err || kind == svn_node_none)
    {
      svn_error_clear(err);
      /* 'chmod 700' permissions: */
      err = svn_io_dir_make(auth_dir,
                            (APR_UREAD | APR_UWRITE | APR_UEXECUTE),
                            pool);
      if (err)
        {
          /* Don't try making subdirs if we can't make the top-level dir. */
          svn_error_clear(err);
          return;
        }
    }

  /* If a provider exists that wants to store credentials in
     ~/.subversion, a subdirectory for the cred_kind must exist. */
  ensure_auth_subdir(auth_dir, SVN_AUTH_CRED_SIMPLE, pool);
  ensure_auth_subdir(auth_dir, SVN_AUTH_CRED_USERNAME, pool);
  ensure_auth_subdir(auth_dir, SVN_AUTH_CRED_SSL_SERVER_TRUST, pool);
  ensure_auth_subdir(auth_dir, SVN_AUTH_CRED_SSL_CLIENT_CERT_PW, pool);
}


svn_error_t *
svn_config_ensure(const char *config_dir, apr_pool_t *pool)
{
  const char *path;
  svn_node_kind_t kind;
  svn_error_t *err;

  /* Ensure that the user-specific config directory exists.  */
  SVN_ERR(svn_config_get_user_config_path(&path, config_dir, NULL, pool));

  if (! path)
    return SVN_NO_ERROR;

  err = svn_io_check_resolved_path(path, &kind, pool);
  if (err)
    {
      /* Don't throw an error, but don't continue. */
      svn_error_clear(err);
      return SVN_NO_ERROR;
    }

  if (kind == svn_node_none)
    {
      err = svn_io_dir_make(path, APR_OS_DEFAULT, pool);
      if (err)
        {
          /* Don't throw an error, but don't continue. */
          svn_error_clear(err);
          return SVN_NO_ERROR;
        }
    }
  else if (kind == svn_node_file)
    {
      /* Somebody put a file where the config directory should be.
         Wacky.  Let's bail. */
      return SVN_NO_ERROR;
    }

  /* Else, there's a configuration directory. */

  /* If we get errors trying to do things below, just stop and return
     success.  There's no _need_ to init a config directory if
     something's preventing it. */

  /** If non-existent, try to create a number of auth/ subdirectories. */
  ensure_auth_dirs(path, pool);

  /** Ensure that the `README.txt' file exists. **/
  SVN_ERR(svn_config_get_user_config_path
          (&path, config_dir, SVN_CONFIG__USR_README_FILE, pool));

  if (! path)  /* highly unlikely, since a previous call succeeded */
    return SVN_NO_ERROR;

  err = svn_io_check_path(path, &kind, pool);
  if (err)
    {
      svn_error_clear(err);
      return SVN_NO_ERROR;
    }

  if (kind == svn_node_none)
    {
      apr_file_t *f;
      const char *contents =
   "This directory holds run-time configuration information for Subversion"  NL
   "clients.  The configuration files all share the same syntax, but you"    NL
   "should examine a particular file to learn what configuration"            NL
   "directives are valid for that file."                                     NL
   ""                                                                        NL
   "The syntax is standard INI format:"                                      NL
   ""                                                                        NL
   "   - Empty lines, and lines starting with '#', are ignored."             NL
   "     The first significant line in a file must be a section header."     NL
   ""                                                                        NL
   "   - A section starts with a section header, which must start in"        NL
   "     the first column:"                                                  NL
   ""                                                                        NL
   "       [section-name]"                                                   NL
   ""                                                                        NL
   "   - An option, which must always appear within a section, is a pair"    NL
   "     (name, value).  There are two valid forms for defining an"          NL
   "     option, both of which must start in the first column:"              NL
   ""                                                                        NL
   "       name: value"                                                      NL
   "       name = value"                                                     NL
   ""                                                                        NL
   "     Whitespace around the separator (:, =) is optional."                NL
   ""                                                                        NL
   "   - Section and option names are case-insensitive, but case is"         NL
   "     preserved."                                                         NL
   ""                                                                        NL
   "   - An option's value may be broken into several lines.  The value"     NL
   "     continuation lines must start with at least one whitespace."        NL
   "     Trailing whitespace in the previous line, the newline character"    NL
   "     and the leading whitespace in the continuation line is compressed"  NL
   "     into a single space character."                                     NL
   ""                                                                        NL
   "   - All leading and trailing whitespace around a value is trimmed,"     NL
   "     but the whitespace within a value is preserved, with the"           NL
   "     exception of whitespace around line continuations, as"              NL
   "     described above."                                                   NL
   ""                                                                        NL
   "   - When a value is a boolean, any of the following strings are"        NL
   "     recognised as truth values (case does not matter):"                 NL
   ""                                                                        NL
   "       true      false"                                                  NL
   "       yes       no"                                                     NL
   "       on        off"                                                    NL
   "       1         0"                                                      NL
   ""                                                                        NL
   "   - When a value is a list, it is comma-separated.  Again, the"         NL
   "     whitespace around each element of the list is trimmed."             NL
   ""                                                                        NL
   "   - Option values may be expanded within a value by enclosing the"      NL
   "     option name in parentheses, preceded by a percent sign and"         NL
   "     followed by an 's':"                                                NL
   ""                                                                        NL
   "       %(name)s"                                                         NL
   ""                                                                        NL
   "     The expansion is performed recursively and on demand, during"       NL
   "     svn_option_get.  The name is first searched for in the same"        NL
   "     section, then in the special [DEFAULT] section. If the name"        NL
   "     is not found, the whole '%(name)s' placeholder is left"             NL
   "     unchanged."                                                         NL
   ""                                                                        NL
   "     Any modifications to the configuration data invalidate all"         NL
   "     previously expanded values, so that the next svn_option_get"        NL
   "     will take the modifications into account."                          NL
   ""                                                                        NL
   "The syntax of the configuration files is a subset of the one used by"    NL
   "Python's ConfigParser module; see"                                       NL
   ""                                                                        NL
   "   https://docs.python.org/3/library/configparser.html"                  NL
   ""                                                                        NL
   "Configuration data in the Windows registry"                              NL
   "=========================================="                              NL
   ""                                                                        NL
   "On Windows, configuration data may also be stored in the registry. The"  NL
   "functions svn_config_read and svn_config_merge will read from the"       NL
   "registry when passed file names of the form:"                            NL
   ""                                                                        NL
   "   REGISTRY:<hive>/path/to/config-key"                                   NL
   ""                                                                        NL
   "The REGISTRY: prefix must be in upper case. The <hive> part must be"     NL
   "one of:"                                                                 NL
   ""                                                                        NL
   "   HKLM for HKEY_LOCAL_MACHINE"                                          NL
   "   HKCU for HKEY_CURRENT_USER"                                           NL
   ""                                                                        NL
   "The values in config-key represent the options in the [DEFAULT] section."NL
   "The keys below config-key represent other sections, and their values"    NL
   "represent the options. Only values of type REG_SZ whose name doesn't"    NL
   "start with a '#' will be used; other values, as well as the keys'"       NL
   "default values, will be ignored."                                        NL
   ""                                                                        NL
   ""                                                                        NL
   "File locations"                                                          NL
   "=============="                                                          NL
   ""                                                                        NL
   "Typically, Subversion uses two config directories, one for site-wide"    NL
   "configuration,"                                                          NL
   ""                                                                        NL
   "  Unix:"                                                                 NL
   "    /etc/subversion/servers"                                             NL
   "    /etc/subversion/config"                                              NL
   "    /etc/subversion/hairstyles"                                          NL
   "  Windows:"                                                              NL
   "    %ALLUSERSPROFILE%\\Application Data\\Subversion\\servers"            NL
   "    %ALLUSERSPROFILE%\\Application Data\\Subversion\\config"             NL
   "    %ALLUSERSPROFILE%\\Application Data\\Subversion\\hairstyles"         NL
   "    REGISTRY:HKLM\\Software\\Tigris.org\\Subversion\\Servers"            NL
   "    REGISTRY:HKLM\\Software\\Tigris.org\\Subversion\\Config"             NL
   "    REGISTRY:HKLM\\Software\\Tigris.org\\Subversion\\Hairstyles"         NL
   ""                                                                        NL
   "and one for per-user configuration:"                                     NL
   ""                                                                        NL
   "  Unix:"                                                                 NL
   "    ~/.subversion/servers"                                               NL
   "    ~/.subversion/config"                                                NL
   "    ~/.subversion/hairstyles"                                            NL
   "  Windows:"                                                              NL
   "    %APPDATA%\\Subversion\\servers"                                      NL
   "    %APPDATA%\\Subversion\\config"                                       NL
   "    %APPDATA%\\Subversion\\hairstyles"                                   NL
   "    REGISTRY:HKCU\\Software\\Tigris.org\\Subversion\\Servers"            NL
   "    REGISTRY:HKCU\\Software\\Tigris.org\\Subversion\\Config"             NL
   "    REGISTRY:HKCU\\Software\\Tigris.org\\Subversion\\Hairstyles"         NL
   ""                                                                        NL;

      err = svn_io_file_open(&f, path,
                             (APR_WRITE | APR_CREATE | APR_EXCL),
                             APR_OS_DEFAULT,
                             pool);

      if (! err)
        {
          SVN_ERR(svn_io_file_write_full(f, contents,
                                         strlen(contents), NULL, pool));
          SVN_ERR(svn_io_file_close(f, pool));
        }

      svn_error_clear(err);
    }

  /** Ensure that the `servers' file exists. **/
  SVN_ERR(svn_config_get_user_config_path
          (&path, config_dir, SVN_CONFIG_CATEGORY_SERVERS, pool));

  if (! path)  /* highly unlikely, since a previous call succeeded */
    return SVN_NO_ERROR;

  err = svn_io_check_path(path, &kind, pool);
  if (err)
    {
      svn_error_clear(err);
      return SVN_NO_ERROR;
    }

  if (kind == svn_node_none)
    {
      apr_file_t *f;
      const char *contents =
        "### This file specifies server-specific parameters,"                NL
        "### including HTTP proxy information, HTTP timeout settings,"       NL
        "### and authentication settings."                                   NL
        "###"                                                                NL
        "### The currently defined server options are:"                      NL
        "###   http-proxy-host            Proxy host for HTTP connection"    NL
        "###   http-proxy-port            Port number of proxy host service" NL
        "###   http-proxy-username        Username for auth to proxy service"NL
        "###   http-proxy-password        Password for auth to proxy service"NL
        "###   http-proxy-exceptions      List of sites that do not use proxy"
                                                                             NL
        "###   http-timeout               Timeout for HTTP requests in seconds"
                                                                             NL
        "###   http-compression           Whether to compress HTTP requests" NL
        "###                              (yes/no/auto)."                    NL
        "###   http-max-connections       Maximum number of parallel server" NL
        "###                              connections to use for any given"  NL
        "###                              HTTP operation."                   NL
        "###   http-chunked-requests      Whether to use chunked transfer"   NL
        "###                              encoding for HTTP requests body."  NL
        "###   http-auth-types            List of HTTP authentication types."NL
        "###   ssl-authority-files        List of files, each of a trusted CA"
                                                                             NL
        "###   ssl-trust-default-ca       Trust the system 'default' CAs"    NL
        "###   ssl-client-cert-file       PKCS#12 format client certificate file"
                                                                             NL
        "###   ssl-client-cert-password   Client Key password, if needed."   NL
        "###   ssl-pkcs11-provider        Name of PKCS#11 provider to use."  NL
        "###   http-library               Which library to use for http/https"
                                                                             NL
        "###                              connections."                      NL
        "###   http-bulk-updates          Whether to request bulk update"    NL
        "###                              responses or to fetch each file"   NL
        "###                              in an individual request. "        NL
        "###   store-passwords            Specifies whether passwords used"  NL
        "###                              to authenticate against a"         NL
        "###                              Subversion server may be cached"   NL
        "###                              to disk in any way."               NL
#ifndef SVN_DISABLE_PLAINTEXT_PASSWORD_STORAGE
        "###   store-plaintext-passwords  Specifies whether passwords may"   NL
        "###                              be cached on disk unencrypted."    NL
#endif
        "###   store-ssl-client-cert-pp   Specifies whether passphrase used" NL
        "###                              to authenticate against a client"  NL
        "###                              certificate may be cached to disk" NL
        "###                              in any way"                        NL
#ifndef SVN_DISABLE_PLAINTEXT_PASSWORD_STORAGE
        "###   store-ssl-client-cert-pp-plaintext"                           NL
        "###                              Specifies whether client cert"     NL
        "###                              passphrases may be cached on disk" NL
        "###                              unencrypted (i.e., as plaintext)." NL
#endif
        "###   store-auth-creds           Specifies whether any auth info"   NL
        "###                              (passwords, server certs, etc.)"   NL
        "###                              may be cached to disk."            NL
        "###   username                   Specifies the default username."   NL
        "###"                                                                NL
        "### Set store-passwords to 'no' to avoid storing new passwords on"  NL
        "### disk in any way, including in password stores.  It defaults to" NL
        "### 'yes', but Subversion will never save your password to disk in" NL
        "### plaintext unless explicitly configured to do so."               NL
        "###"                                                                NL
#ifndef SVN_DISABLE_PLAINTEXT_PASSWORD_STORAGE
        "### Set store-plaintext-passwords to 'no' to avoid storing new"     NL
        "### passwords in unencrypted form in the auth/ area of your config" NL
        "### directory. Set it to 'yes' to allow Subversion to store"        NL
        "### unencrypted passwords in the auth/ area.  The default is"       NL
        "### 'ask', which means that Subversion will ask you before"         NL
        "### saving a password to disk in unencrypted form.  Note that"      NL
        "### this option has no effect if either 'store-passwords' or "      NL
        "### 'store-auth-creds' is set to 'no'."                             NL
        "###"                                                                NL
#endif
        "### Set store-ssl-client-cert-pp to 'no' to avoid storing new ssl"  NL
        "### client certificate passphrases in the auth/ area of your"       NL
        "### config directory.  It defaults to 'yes', but Subversion will"   NL
        "### never save your passphrase to disk in plaintext unless"         NL
        "### explicitly configured to do so."                                NL
        "###"                                                                NL
#ifndef SVN_DISABLE_PLAINTEXT_PASSWORD_STORAGE
        "### Set store-ssl-client-cert-pp-plaintext to 'no' to avoid storing"NL
        "### new passphrases in unencrypted form in the auth/ area of your"  NL
        "### config directory.  Set it to 'yes' to allow Subversion to"      NL
        "### store unencrypted passphrases in the auth/ area.  The default"  NL
        "### is 'ask', which means that Subversion will prompt before"       NL
        "### saving a passphrase to disk in unencrypted form.  Note that"    NL
        "### this option has no effect if either 'store-auth-creds' or "     NL
        "### 'store-ssl-client-cert-pp' is set to 'no'."                     NL
        "###"                                                                NL
#endif
        "### Set store-auth-creds to 'no' to avoid storing any new Subversion"
                                                                             NL
        "### credentials in the auth/ area of your config directory."        NL
        "### Note that this includes SSL server certificates."               NL
        "### It defaults to 'yes'."                                          NL
        "###"                                                                NL
        "### Note that setting a 'store-*' option to 'no' only prevents"     NL
        "### saving of *new* passwords, passphrases or other credentials."   NL
        "### It does not remove or invalidate existing stored credentials."  NL
        "### To do that, see the 'svn auth --remove' command, or remove the" NL
        "### cache files by hand as described in the Subversion book at"     NL
        "### http://svnbook.red-bean.com/nightly/en/svn.serverconfig.netmodel.html#svn.tour.initial.authn-cache-purge"
                                                                             NL
        "###"                                                                NL
        "### HTTP timeouts, if given, are specified in seconds.  A timeout"  NL
        "### of 0, i.e. zero, causes a builtin default to be used."          NL
        "###"                                                                NL
        "### Most users will not need to explicitly set the http-library"    NL
        "### option, but valid values for the option include:"               NL
        "###    'serf': Serf-based module (Subversion 1.5 - present)"        NL
        "### Availability of these modules may depend on your specific"      NL
        "### Subversion distribution."                                       NL
        "###"                                                                NL
        "### The commented-out examples below are intended only to"          NL
        "### demonstrate how to use this file; any resemblance to actual"    NL
        "### servers, living or dead, is entirely coincidental."             NL
        ""                                                                   NL
        "### In the 'groups' section, the URL of the repository you're"      NL
        "### trying to access is matched against the patterns on the right." NL
        "### If a match is found, the server options are taken from the"     NL
        "### section with the corresponding name on the left."               NL
        ""                                                                   NL
        "[groups]"                                                           NL
        "# group1 = *.collab.net"                                            NL
        "# othergroup = repository.blarggitywhoomph.com"                     NL
        "# thirdgroup = *.example.com"                                       NL
        ""                                                                   NL
        "### Information for the first group:"                               NL
        "# [group1]"                                                         NL
        "# http-proxy-host = proxy1.some-domain-name.com"                    NL
        "# http-proxy-port = 80"                                             NL
        "# http-proxy-username = blah"                                       NL
        "# http-proxy-password = doubleblah"                                 NL
        "# http-timeout = 60"                                                NL
#ifndef SVN_DISABLE_PLAINTEXT_PASSWORD_STORAGE
        "# store-plaintext-passwords = no"                                   NL
#endif
        "# username = harry"                                                 NL
        ""                                                                   NL
        "### Information for the second group:"                              NL
        "# [othergroup]"                                                     NL
        "# http-proxy-host = proxy2.some-domain-name.com"                    NL
        "# http-proxy-port = 9000"                                           NL
        "# No username and password for the proxy, so use the defaults below."
                                                                             NL
        ""                                                                   NL
        "### You can set default parameters in the 'global' section."        NL
        "### These parameters apply if no corresponding parameter is set in" NL
        "### a specifically matched group as shown above.  Thus, if you go"  NL
        "### through the same proxy server to reach every site on the"       NL
        "### Internet, you probably just want to put that server's"          NL
        "### information in the 'global' section and not bother with"        NL
        "### 'groups' or any other sections."                                NL
        "###"                                                                NL
        "### Most people might want to configure password caching"           NL
        "### parameters here, but you can also configure them per server"    NL
        "### group (per-group settings override global settings)."           NL
        "###"                                                                NL
        "### If you go through a proxy for all but a few sites, you can"     NL
        "### list those exceptions under 'http-proxy-exceptions'.  This only"NL
        "### overrides defaults, not explicitly matched server names."       NL
        "###"                                                                NL
        "### 'ssl-authority-files' is a semicolon-delimited list of files,"  NL
        "### each pointing to a PEM-encoded Certificate Authority (CA) "     NL
        "### SSL certificate.  See details above for overriding security "   NL
        "### due to SSL."                                                    NL
        "[global]"                                                           NL
        "# http-proxy-exceptions = *.exception.com, www.internal-site.org"   NL
        "# http-proxy-host = defaultproxy.whatever.com"                      NL
        "# http-proxy-port = 7000"                                           NL
        "# http-proxy-username = defaultusername"                            NL
        "# http-proxy-password = defaultpassword"                            NL
        "# http-compression = auto"                                          NL
        "# No http-timeout, so just use the builtin default."                NL
        "# ssl-authority-files = /path/to/CAcert.pem;/path/to/CAcert2.pem"   NL
        "#"                                                                  NL
        "# Password / passphrase caching parameters:"                        NL
        "# store-passwords = no"                                             NL
        "# store-ssl-client-cert-pp = no"                                    NL
#ifndef SVN_DISABLE_PLAINTEXT_PASSWORD_STORAGE
        "# store-plaintext-passwords = no"                                   NL
        "# store-ssl-client-cert-pp-plaintext = no"                          NL
#endif
        ;

      err = svn_io_file_open(&f, path,
                             (APR_WRITE | APR_CREATE | APR_EXCL),
                             APR_OS_DEFAULT,
                             pool);

      if (! err)
        {
          SVN_ERR(svn_io_file_write_full(f, contents,
                                         strlen(contents), NULL, pool));
          SVN_ERR(svn_io_file_close(f, pool));
        }

      svn_error_clear(err);
    }

  /** Ensure that the `config' file exists. **/
  SVN_ERR(svn_config_get_user_config_path
          (&path, config_dir, SVN_CONFIG_CATEGORY_CONFIG, pool));

  if (! path)  /* highly unlikely, since a previous call succeeded */
    return SVN_NO_ERROR;

  err = svn_io_check_path(path, &kind, pool);
  if (err)
    {
      svn_error_clear(err);
      return SVN_NO_ERROR;
    }

  if (kind == svn_node_none)
    {
      apr_file_t *f;
      const char *contents =
        "### This file configures various client-side behaviors."            NL
        "###"                                                                NL
        "### The commented-out examples below are intended to demonstrate"   NL
        "### how to use this file."                                          NL
        ""                                                                   NL
        "### Section for authentication and authorization customizations."   NL
        "[auth]"                                                             NL
        "### Set password stores used by Subversion. They should be"         NL
        "### delimited by spaces or commas. The order of values determines"  NL
        "### the order in which password stores are used."                   NL
        "### Valid password stores:"                                         NL
        "###   gnome-keyring        (Unix-like systems)"                     NL
        "###   kwallet              (Unix-like systems)"                     NL
        "###   gpg-agent            (Unix-like systems)"                     NL
        "###   keychain             (Mac OS X)"                              NL
        "###   windows-cryptoapi    (Windows)"                               NL
#ifdef SVN_HAVE_KEYCHAIN_SERVICES
        "# password-stores = keychain"                                       NL
#elif defined(WIN32) && !defined(__MINGW32__)
        "# password-stores = windows-cryptoapi"                              NL
#else
        "# password-stores = gpg-agent,gnome-keyring,kwallet"                NL
#endif
        "### To disable all password stores, use an empty list:"             NL
        "# password-stores ="                                                NL
#ifdef SVN_HAVE_KWALLET
        "###"                                                                NL
        "### Set KWallet wallet used by Subversion. If empty or unset,"      NL
        "### then the default network wallet will be used."                  NL
        "# kwallet-wallet ="                                                 NL
        "###"                                                                NL
        "### Include PID (Process ID) in Subversion application name when"   NL
        "### using KWallet. It defaults to 'no'."                            NL
        "# kwallet-svn-application-name-with-pid = yes"                      NL
#endif
        "###"                                                                NL
        "### Set ssl-client-cert-file-prompt to 'yes' to cause the client"   NL
        "### to prompt for a path to a client cert file when the server"     NL
        "### requests a client cert but no client cert file is found in the" NL
        "### expected place (see the 'ssl-client-cert-file' option in the"   NL
        "### 'servers' configuration file). Defaults to 'no'."               NL
        "# ssl-client-cert-file-prompt = no"                                 NL
        "###"                                                                NL
        "### The rest of the [auth] section in this file has been deprecated."
                                                                             NL
        "### Both 'store-passwords' and 'store-auth-creds' can now be"       NL
        "### specified in the 'servers' file in your config directory"       NL
        "### and are documented there. Anything specified in this section "  NL
        "### is overridden by settings specified in the 'servers' file."     NL
        "# store-passwords = no"                                             NL
        "# store-auth-creds = no"                                            NL
        ""                                                                   NL
        "### Section for configuring external helper applications."          NL
        "[helpers]"                                                          NL
        "### Set editor-cmd to the command used to invoke your text editor." NL
        "###   This will override the environment variables that Subversion" NL
        "###   examines by default to find this information ($EDITOR, "      NL
        "###   et al)."                                                      NL
        "# editor-cmd = editor (vi, emacs, notepad, etc.)"                   NL
        "### Set diff-cmd to the absolute path of your 'diff' program."      NL
        "###   This will override the compile-time default, which is to use" NL
        "###   Subversion's internal diff implementation."                   NL
        "# diff-cmd = diff_program (diff, gdiff, etc.)"                      NL
        "### Diff-extensions are arguments passed to an external diff"       NL
        "### program or to Subversion's internal diff implementation."       NL
        "### Set diff-extensions to override the default arguments ('-u')."  NL
        "# diff-extensions = -u -p"                                          NL
        "### Set diff3-cmd to the absolute path of your 'diff3' program."    NL
        "###   This will override the compile-time default, which is to use" NL
        "###   Subversion's internal diff3 implementation."                  NL
        "# diff3-cmd = diff3_program (diff3, gdiff3, etc.)"                  NL
        "### Set diff3-has-program-arg to 'yes' if your 'diff3' program"     NL
        "###   accepts the '--diff-program' option."                         NL
        "# diff3-has-program-arg = [yes | no]"                               NL
        "### Set merge-tool-cmd to the command used to invoke your external" NL
        "### merging tool of choice. Subversion will pass 5 arguments to"    NL
        "### the specified command: base theirs mine merged wcfile"          NL
        "# merge-tool-cmd = merge_command"                                   NL
        ""                                                                   NL
        "### Section for configuring tunnel agents."                         NL
        "[tunnels]"                                                          NL
        "### Configure svn protocol tunnel schemes here.  By default, only"  NL
        "### the 'ssh' scheme is defined.  You can define other schemes to"  NL
        "### be used with 'svn+scheme://hostname/path' URLs.  A scheme"      NL
        "### definition is simply a command, optionally prefixed by an"      NL
        "### environment variable name which can override the command if it" NL
        "### is defined.  The command (or environment variable) may contain" NL
        "### arguments, using standard shell quoting for arguments with"     NL
        "### spaces.  The command will be invoked as:"                       NL
        "###   <command> <hostname> svnserve -t"                             NL
        "### (If the URL includes a username, then the hostname will be"     NL
        "### passed to the tunnel agent as <user>@<hostname>.)  If the"      NL
        "### built-in ssh scheme were not predefined, it could be defined"   NL
        "### as:"                                                            NL
        "# ssh = $SVN_SSH ssh -q --"                                         NL
        "### If you wanted to define a new 'rsh' scheme, to be used with"    NL
        "### 'svn+rsh:' URLs, you could do so as follows:"                   NL
        "# rsh = rsh --"                                                     NL
        "### Or, if you wanted to specify a full path and arguments:"        NL
        "# rsh = /path/to/rsh -l myusername --"                              NL
        "### On Windows, if you are specifying a full path to a command,"    NL
        "### use a forward slash (/) or a paired backslash (\\\\) as the"    NL
        "### path separator.  A single backslash will be treated as an"      NL
        "### escape for the following character."                            NL
        ""                                                                   NL
        "### Section for configuring miscellaneous Subversion options."      NL
        "[miscellany]"                                                       NL
        "### Set global-ignores to a set of whitespace-delimited globs"      NL
        "### which Subversion will ignore in its 'status' output, and"       NL
        "### while importing or adding files and directories."               NL
        "### '*' matches leading dots, e.g. '*.rej' matches '.foo.rej'."     NL
        "# global-ignores = " SVN_CONFIG__DEFAULT_GLOBAL_IGNORES_LINE_1      NL
        "#   " SVN_CONFIG__DEFAULT_GLOBAL_IGNORES_LINE_2                     NL
        "### Set log-encoding to the default encoding for log messages"      NL
        "# log-encoding = latin1"                                            NL
        "### Set use-commit-times to make checkout/update/switch/revert"     NL
        "### put last-committed timestamps on every file touched."           NL
        "# use-commit-times = yes"                                           NL
        "### Set no-unlock to prevent 'svn commit' from automatically"       NL
        "### releasing locks on files."                                      NL
        "# no-unlock = yes"                                                  NL
        "### Set mime-types-file to a MIME type registry file, used to"      NL
        "### provide hints to Subversion's MIME type auto-detection"         NL
        "### algorithm."                                                     NL
        "# mime-types-file = /path/to/mime.types"                            NL
        "### Set preserved-conflict-file-exts to a whitespace-delimited"     NL
        "### list of patterns matching file extensions which should be"      NL
        "### preserved in generated conflict file names.  By default,"       NL
        "### conflict files use custom extensions."                          NL
        "# preserved-conflict-file-exts = doc ppt xls od?"                   NL
        "### Set enable-auto-props to 'yes' to enable automatic properties"  NL
        "### for 'svn add' and 'svn import', it defaults to 'no'."           NL
        "### Automatic properties are defined in the section 'auto-props'."  NL
        "# enable-auto-props = yes"                                          NL
#ifdef SVN_HAVE_LIBMAGIC
        "### Set enable-magic-file to 'no' to disable magic file detection"  NL
        "### of the file type when automatically setting svn:mime-type. It"  NL
        "### defaults to 'yes' if magic file support is possible."           NL
        "# enable-magic-file = yes"                                          NL
#endif
        "### Set interactive-conflicts to 'no' to disable interactive"       NL
        "### conflict resolution prompting.  It defaults to 'yes'."          NL
        "# interactive-conflicts = no"                                       NL
        "### Set memory-cache-size to define the size of the memory cache"   NL
        "### used by the client when accessing a FSFS repository via"        NL
        "### ra_local (the file:// scheme). The value represents the number" NL
        "### of MB used by the cache."                                       NL
        "# memory-cache-size = 16"                                           NL
        "### Set diff-ignore-content-type to 'yes' to cause 'svn diff' to"   NL
        "### attempt to show differences of all modified files regardless"   NL
        "### of their MIME content type.  By default, Subversion will only"  NL
        "### attempt to show differences for files believed to have human-"  NL
        "### readable (non-binary) content.  This option is especially"      NL
        "### useful when Subversion is configured (via the 'diff-cmd'"       NL
        "### option) to employ an external differencing tool which is able"  NL
        "### to show meaningful differences for binary file formats.  [New"  NL
        "### in 1.9]"                                                        NL
        "# diff-ignore-content-type = no"                                    NL
        ""                                                                   NL
        "### Section for configuring automatic properties."                  NL
        "[auto-props]"                                                       NL
        "### The format of the entries is:"                                  NL
        "###   file-name-pattern = propname[=value][;propname[=value]...]"   NL
        "### The file-name-pattern can contain wildcards (such as '*' and"   NL
        "### '?').  All entries which match (case-insensitively) will be"    NL
        "### applied to the file.  Note that auto-props functionality"       NL
        "### must be enabled, which is typically done by setting the"        NL
        "### 'enable-auto-props' option."                                    NL
        "# *.c = svn:eol-style=native"                                       NL
        "# *.cpp = svn:eol-style=native"                                     NL
        "# *.h = svn:keywords=Author Date Id Rev URL;svn:eol-style=native"   NL
        "# *.dsp = svn:eol-style=CRLF"                                       NL
        "# *.dsw = svn:eol-style=CRLF"                                       NL
        "# *.sh = svn:eol-style=native;svn:executable"                       NL
        "# *.txt = svn:eol-style=native;svn:keywords=Author Date Id Rev URL;"NL
        "# *.png = svn:mime-type=image/png"                                  NL
        "# *.jpg = svn:mime-type=image/jpeg"                                 NL
        "# Makefile = svn:eol-style=native"                                  NL
        ""                                                                   NL
        "### Section for configuring working copies."                        NL
        "[working-copy]"                                                     NL
        "### Set to a list of the names of specific clients that should use" NL
        "### exclusive SQLite locking of working copies.  This increases the"NL
        "### performance of the client but prevents concurrent access by"    NL
        "### other clients.  Third-party clients may also support this"      NL
        "### option."                                                        NL
        "### Possible values:"                                               NL
        "###   svn                (the command line client)"                 NL
        "# exclusive-locking-clients ="                                      NL
        "### Set to true to enable exclusive SQLite locking of working"      NL
        "### copies by all clients using the 1.8 APIs.  Enabling this may"   NL
        "### cause some clients to fail to work properly. This does not have"NL
        "### to be set for exclusive-locking-clients to work."               NL
        "# exclusive-locking = false"                                        NL
        "### Set the SQLite busy timeout in milliseconds: the maximum time"  NL
        "### the client waits to get access to the SQLite database before"   NL
        "### returning an error.  The default is 10000, i.e. 10 seconds."    NL
        "### Longer values may be useful when exclusive locking is enabled." NL
        "# busy-timeout = 10000"                                             NL
        ;

      err = svn_io_file_open(&f, path,
                             (APR_WRITE | APR_CREATE | APR_EXCL),
                             APR_OS_DEFAULT,
                             pool);

      if (! err)
        {
          SVN_ERR(svn_io_file_write_full(f, contents,
                                         strlen(contents), NULL, pool));
          SVN_ERR(svn_io_file_close(f, pool));
        }

      svn_error_clear(err);
    }

  return SVN_NO_ERROR;
}

svn_error_t *
svn_config_get_user_config_path(const char **path,
                                const char *config_dir,
                                const char *fname,
                                apr_pool_t *pool)
{
  *path= NULL;

  /* Note that even if fname is null, svn_dirent_join_many will DTRT. */

  if (config_dir)
    {
      *path = svn_dirent_join_many(pool, config_dir, fname, SVN_VA_NULL);
      return SVN_NO_ERROR;
    }

#ifdef WIN32
  {
    const char *folder;
    SVN_ERR(svn_config__win_config_path(&folder, FALSE, pool, pool));

    if (! folder)
      return SVN_NO_ERROR;

    *path = svn_dirent_join_many(pool, folder,
                                 SVN_CONFIG__SUBDIRECTORY, fname, SVN_VA_NULL);
  }

#elif defined(__HAIKU__)
  {
    char folder[B_PATH_NAME_LENGTH];

    status_t error = find_directory(B_USER_SETTINGS_DIRECTORY, -1, false,
                                    folder, sizeof(folder));
    if (error)
      return SVN_NO_ERROR;

    *path = svn_dirent_join_many(pool, folder,
                                 SVN_CONFIG__USR_DIRECTORY, fname,
                                 SVN_VA_NULL);
  }
#else  /* ! WIN32 && !__HAIKU__ */

  {
    const char *homedir = svn_user_get_homedir(pool);
    if (! homedir)
      return SVN_NO_ERROR;
    *path = svn_dirent_join_many(pool,
                                 homedir,
                               SVN_CONFIG__USR_DIRECTORY, fname, SVN_VA_NULL);
  }
#endif /* WIN32 */

  return SVN_NO_ERROR;
}