aboutsummaryrefslogtreecommitdiff
path: root/gdb/top.c
blob: 213c68cab9a07501d4701682c7d4478865d52467 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
/* Top level stuff for GDB, the GNU debugger.

   Copyright (C) 1986-2012 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "gdbcmd.h"
#include "call-cmds.h"
#include "cli/cli-cmds.h"
#include "cli/cli-script.h"
#include "cli/cli-setshow.h"
#include "cli/cli-decode.h"
#include "symtab.h"
#include "inferior.h"
#include "exceptions.h"
#include <signal.h>
#include "target.h"
#include "breakpoint.h"
#include "gdbtypes.h"
#include "expression.h"
#include "value.h"
#include "language.h"
#include "terminal.h"		/* For job_control.  */
#include "annotate.h"
#include "completer.h"
#include "top.h"
#include "version.h"
#include "serial.h"
#include "doublest.h"
#include "gdb_assert.h"
#include "main.h"
#include "event-loop.h"
#include "gdbthread.h"
#include "python/python.h"
#include "interps.h"
#include "observer.h"

/* readline include files.  */
#include "readline/readline.h"
#include "readline/history.h"

/* readline defines this.  */
#undef savestring

#include <sys/types.h>

#include "event-top.h"
#include "gdb_string.h"
#include "gdb_stat.h"
#include <ctype.h>
#include "ui-out.h"
#include "cli-out.h"

#define PROMPT(X) the_prompts.prompt_stack[the_prompts.top + X].prompt
#define PREFIX(X) the_prompts.prompt_stack[the_prompts.top + X].prefix
#define SUFFIX(X) the_prompts.prompt_stack[the_prompts.top + X].suffix

/* Default command line prompt.  This is overriden in some configs.  */

#ifndef DEFAULT_PROMPT
#define DEFAULT_PROMPT	"(gdb) "
#endif

/* Initialization file name for gdb.  This is overridden in some configs.  */

#ifndef PATH_MAX
# ifdef FILENAME_MAX
#  define PATH_MAX FILENAME_MAX
# else
#  define PATH_MAX 512
# endif
#endif

#ifndef	GDBINIT_FILENAME
#define	GDBINIT_FILENAME	".gdbinit"
#endif
char gdbinit[PATH_MAX + 1] = GDBINIT_FILENAME;

int inhibit_gdbinit = 0;

/* If nonzero, and GDB has been configured to be able to use windows,
   attempt to open them upon startup.  */

int use_windows = 0;

extern char lang_frame_mismatch_warn[];		/* language.c */

/* Flag for whether we want to confirm potentially dangerous
   operations.  Default is yes.  */

int confirm = 1;

static void
show_confirm (struct ui_file *file, int from_tty,
	      struct cmd_list_element *c, const char *value)
{
  fprintf_filtered (file, _("Whether to confirm potentially "
			    "dangerous operations is %s.\n"),
		    value);
}

/* stdio stream that command input is being read from.  Set to stdin
   normally.  Set by source_command to the file we are sourcing.  Set
   to NULL if we are executing a user-defined command or interacting
   via a GUI.  */

FILE *instream;

/* Flag to indicate whether a user defined command is currently running.  */

int in_user_command;

/* Current working directory.  */

char *current_directory;

/* The directory name is actually stored here (usually).  */
char gdb_dirbuf[1024];

/* Function to call before reading a command, if nonzero.
   The function receives two args: an input stream,
   and a prompt string.  */

void (*window_hook) (FILE *, char *);

int epoch_interface;
int xgdb_verbose;

/* Buffer used for reading command lines, and the size
   allocated for it so far.  */

char *saved_command_line;
int saved_command_line_size = 100;

/* Nonzero if the current command is modified by "server ".  This
   affects things like recording into the command history, commands
   repeating on RETURN, etc.  This is so a user interface (emacs, GUI,
   whatever) can issue its own commands and also send along commands
   from the user, and have the user not notice that the user interface
   is issuing commands too.  */
int server_command;

/* Baud rate specified for talking to serial target systems.  Default
   is left as -1, so targets can choose their own defaults.  */
/* FIXME: This means that "show remotebaud" and gr_files_info can
   print -1 or (unsigned int)-1.  This is a Bad User Interface.  */

int baud_rate = -1;

/* Timeout limit for response from target.  */

/* The default value has been changed many times over the years.  It 
   was originally 5 seconds.  But that was thought to be a long time 
   to sit and wait, so it was changed to 2 seconds.  That was thought
   to be plenty unless the connection was going through some terminal 
   server or multiplexer or other form of hairy serial connection.

   In mid-1996, remote_timeout was moved from remote.c to top.c and 
   it began being used in other remote-* targets.  It appears that the
   default was changed to 20 seconds at that time, perhaps because the
   Renesas E7000 ICE didn't always respond in a timely manner.

   But if 5 seconds is a long time to sit and wait for retransmissions,
   20 seconds is far worse.  This demonstrates the difficulty of using 
   a single variable for all protocol timeouts.

   As remote.c is used much more than remote-e7000.c, it was changed 
   back to 2 seconds in 1999.  */

int remote_timeout = 2;

/* Non-zero tells remote* modules to output debugging info.  */

int remote_debug = 0;

/* Sbrk location on entry to main.  Used for statistics only.  */
#ifdef HAVE_SBRK
char *lim_at_start;
#endif

/* Hooks for alternate command interfaces.  */

/* Called after most modules have been initialized, but before taking
   users command file.

   If the UI fails to initialize and it wants GDB to continue using
   the default UI, then it should clear this hook before returning.  */

void (*deprecated_init_ui_hook) (char *argv0);

/* This hook is called from within gdb's many mini-event loops which
   could steal control from a real user interface's event loop.  It
   returns non-zero if the user is requesting a detach, zero
   otherwise.  */

int (*deprecated_ui_loop_hook) (int);

/* Called instead of command_loop at top level.  Can be invoked via
   throw_exception().  */

void (*deprecated_command_loop_hook) (void);


/* Called from print_frame_info to list the line we stopped in.  */

void (*deprecated_print_frame_info_listing_hook) (struct symtab * s, 
						  int line,
						  int stopline, 
						  int noerror);
/* Replaces most of query.  */

int (*deprecated_query_hook) (const char *, va_list);

/* Replaces most of warning.  */

void (*deprecated_warning_hook) (const char *, va_list);

/* These three functions support getting lines of text from the user.
   They are used in sequence.  First deprecated_readline_begin_hook is
   called with a text string that might be (for example) a message for
   the user to type in a sequence of commands to be executed at a
   breakpoint.  If this function calls back to a GUI, it might take
   this opportunity to pop up a text interaction window with this
   message.  Next, deprecated_readline_hook is called with a prompt
   that is emitted prior to collecting the user input.  It can be
   called multiple times.  Finally, deprecated_readline_end_hook is
   called to notify the GUI that we are done with the interaction
   window and it can close it.  */

void (*deprecated_readline_begin_hook) (char *, ...);
char *(*deprecated_readline_hook) (char *);
void (*deprecated_readline_end_hook) (void);

/* Called as appropriate to notify the interface that we have attached
   to or detached from an already running process.  */

void (*deprecated_attach_hook) (void);
void (*deprecated_detach_hook) (void);

/* Called during long calculations to allow GUI to repair window
   damage, and to check for stop buttons, etc...  */

void (*deprecated_interactive_hook) (void);

/* Tell the GUI someone changed the register REGNO.  -1 means
   that the caller does not know which register changed or
   that several registers have changed (see value_assign).  */
void (*deprecated_register_changed_hook) (int regno);

/* Called when going to wait for the target.  Usually allows the GUI
   to run while waiting for target events.  */

ptid_t (*deprecated_target_wait_hook) (ptid_t ptid,
				       struct target_waitstatus *status,
				       int options);

/* Used by UI as a wrapper around command execution.  May do various
   things like enabling/disabling buttons, etc...  */

void (*deprecated_call_command_hook) (struct cmd_list_element * c, 
				      char *cmd, int from_tty);

/* Called after a `set' command has finished.  Is only run if the
   `set' command succeeded.  */

void (*deprecated_set_hook) (struct cmd_list_element * c);

/* Called when the current thread changes.  Argument is thread id.  */

void (*deprecated_context_hook) (int id);

/* Handler for SIGHUP.  */

#ifdef SIGHUP
/* NOTE 1999-04-29: This function will be static again, once we modify
   gdb to use the event loop as the default command loop and we merge
   event-top.c into this file, top.c.  */
/* static */ void
quit_cover (void)
{
  /* Stop asking user for confirmation --- we're exiting.  This
     prevents asking the user dumb questions.  */
  confirm = 0;
  quit_command ((char *) 0, 0);
}
#endif /* defined SIGHUP */

/* Line number we are currently in, in a file which is being sourced.  */
/* NOTE 1999-04-29: This variable will be static again, once we modify
   gdb to use the event loop as the default command loop and we merge
   event-top.c into this file, top.c.  */
/* static */ int source_line_number;

/* Name of the file we are sourcing.  */
/* NOTE 1999-04-29: This variable will be static again, once we modify
   gdb to use the event loop as the default command loop and we merge
   event-top.c into this file, top.c.  */
/* static */ const char *source_file_name;

/* Clean up on error during a "source" command (or execution of a
   user-defined command).  */

void
do_restore_instream_cleanup (void *stream)
{
  /* Restore the previous input stream.  */
  instream = stream;
}

/* Read commands from STREAM.  */
void
read_command_file (FILE *stream)
{
  struct cleanup *cleanups;

  cleanups = make_cleanup (do_restore_instream_cleanup, instream);
  instream = stream;
  command_loop ();
  do_cleanups (cleanups);
}

void (*pre_init_ui_hook) (void);

#ifdef __MSDOS__
static void
do_chdir_cleanup (void *old_dir)
{
  chdir (old_dir);
  xfree (old_dir);
}
#endif

struct cleanup *
prepare_execute_command (void)
{
  struct value *mark;
  struct cleanup *cleanup;

  mark = value_mark ();
  cleanup = make_cleanup_value_free_to_mark (mark);

  /* With multiple threads running while the one we're examining is
     stopped, the dcache can get stale without us being able to detect
     it.  For the duration of the command, though, use the dcache to
     help things like backtrace.  */
  if (non_stop)
    target_dcache_invalidate ();

  return cleanup;
}

/* Tell the user if the language has changed (except first time) after
   executing a command.  */

void
check_frame_language_change (void)
{
  static int warned = 0;

  /* First make sure that a new frame has been selected, in case the
     command or the hooks changed the program state.  */
  deprecated_safe_get_selected_frame ();
  if (current_language != expected_language)
    {
      if (language_mode == language_mode_auto && info_verbose)
	{
	  language_info (1);	/* Print what changed.  */
	}
      warned = 0;
    }

  /* Warn the user if the working language does not match the language
     of the current frame.  Only warn the user if we are actually
     running the program, i.e. there is a stack.  */
  /* FIXME: This should be cacheing the frame and only running when
     the frame changes.  */

  if (has_stack_frames ())
    {
      enum language flang;

      flang = get_frame_language ();
      if (!warned
	  && flang != language_unknown
	  && flang != current_language->la_language)
	{
	  printf_filtered ("%s\n", lang_frame_mismatch_warn);
	  warned = 1;
	}
    }
}

/* Execute the line P as a command, in the current user context.
   Pass FROM_TTY as second argument to the defining function.  */

void
execute_command (char *p, int from_tty)
{
  struct cleanup *cleanup_if_error, *cleanup;
  struct cmd_list_element *c;
  char *line;

  cleanup_if_error = make_bpstat_clear_actions_cleanup ();
  cleanup = prepare_execute_command ();

  /* Force cleanup of any alloca areas if using C alloca instead of
     a builtin alloca.  */
  alloca (0);

  /* This can happen when command_line_input hits end of file.  */
  if (p == NULL)
    {
      do_cleanups (cleanup);
      return;
    }

  target_log_command (p);

  while (*p == ' ' || *p == '\t')
    p++;
  if (*p)
    {
      char *arg;
      line = p;

      /* If trace-commands is set then this will print this command.  */
      print_command_trace (p);

      c = lookup_cmd (&p, cmdlist, "", 0, 1);

      /* Pass null arg rather than an empty one.  */
      arg = *p ? p : 0;

      /* FIXME: cagney/2002-02-02: The c->type test is pretty dodgy
         while the is_complete_command(cfunc) test is just plain
         bogus.  They should both be replaced by a test of the form
         c->strip_trailing_white_space_p.  */
      /* NOTE: cagney/2002-02-02: The function.cfunc in the below
         can't be replaced with func.  This is because it is the
         cfunc, and not the func, that has the value that the
         is_complete_command hack is testing for.  */
      /* Clear off trailing whitespace, except for set and complete
         command.  */
      if (arg
	  && c->type != set_cmd
	  && !is_complete_command (c))
	{
	  p = arg + strlen (arg) - 1;
	  while (p >= arg && (*p == ' ' || *p == '\t'))
	    p--;
	  *(p + 1) = '\0';
	}

      /* If this command has been pre-hooked, run the hook first.  */
      execute_cmd_pre_hook (c);

      if (c->flags & DEPRECATED_WARN_USER)
	deprecated_cmd_warning (&line);

      /* c->user_commands would be NULL in the case of a python command.  */
      if (c->class == class_user && c->user_commands)
	execute_user_command (c, arg);
      else if (c->type == set_cmd || c->type == show_cmd)
	do_setshow_command (arg, from_tty, c);
      else if (!cmd_func_p (c))
	error (_("That is not a command, just a help topic."));
      else if (deprecated_call_command_hook)
	deprecated_call_command_hook (c, arg, from_tty);
      else
	cmd_func (c, arg, from_tty);

      /* If the interpreter is in sync mode (we're running a user
	 command's list, running command hooks or similars), and we
	 just ran a synchronous command that started the target, wait
	 for that command to end.  */
      if (!interpreter_async && sync_execution)
	{
	  while (gdb_do_one_event () >= 0)
	    if (!sync_execution)
	      break;
	}

      /* If this command has been post-hooked, run the hook last.  */
      execute_cmd_post_hook (c);

    }

  check_frame_language_change ();

  do_cleanups (cleanup);
  discard_cleanups (cleanup_if_error);
}

/* Run execute_command for P and FROM_TTY.  Capture its output into the
   returned string, do not display it to the screen.  BATCH_FLAG will be
   temporarily set to true.  */

char *
execute_command_to_string (char *p, int from_tty)
{
  struct ui_file *str_file;
  struct cleanup *cleanup;
  char *retval;

  /* GDB_STDOUT should be better already restored during these
     restoration callbacks.  */
  cleanup = set_batch_flag_and_make_cleanup_restore_page_info ();

  make_cleanup_restore_integer (&interpreter_async);
  interpreter_async = 0;

  str_file = mem_fileopen ();

  make_cleanup_ui_file_delete (str_file);
  make_cleanup_restore_ui_file (&gdb_stdout);
  make_cleanup_restore_ui_file (&gdb_stderr);
  make_cleanup_restore_ui_file (&gdb_stdlog);
  make_cleanup_restore_ui_file (&gdb_stdtarg);
  make_cleanup_restore_ui_file (&gdb_stdtargerr);

  if (ui_out_redirect (current_uiout, str_file) < 0)
    warning (_("Current output protocol does not support redirection"));
  else
    make_cleanup_ui_out_redirect_pop (current_uiout);

  gdb_stdout = str_file;
  gdb_stderr = str_file;
  gdb_stdlog = str_file;
  gdb_stdtarg = str_file;
  gdb_stdtargerr = str_file;

  execute_command (p, from_tty);

  retval = ui_file_xstrdup (str_file, NULL);

  do_cleanups (cleanup);

  return retval;
}

/* Read commands from `instream' and execute them
   until end of file or error reading instream.  */

void
command_loop (void)
{
  struct cleanup *old_chain;
  char *command;
  int stdin_is_tty = ISATTY (stdin);

  while (instream && !feof (instream))
    {
      if (window_hook && instream == stdin)
	(*window_hook) (instream, get_prompt ());

      quit_flag = 0;
      if (instream == stdin && stdin_is_tty)
	reinitialize_more_filter ();
      old_chain = make_cleanup (null_cleanup, 0);

      /* Get a command-line.  This calls the readline package.  */
      command = command_line_input (instream == stdin ?
				    get_prompt () : (char *) NULL,
				    instream == stdin, "prompt");
      if (command == 0)
	{
	  do_cleanups (old_chain);
	  return;
	}

      make_command_stats_cleanup (1);

      execute_command (command, instream == stdin);

      /* Do any commands attached to breakpoint we are stopped at.  */
      bpstat_do_actions ();

      do_cleanups (old_chain);
    }
}

/* When nonzero, cause dont_repeat to do nothing.  This should only be
   set via prevent_dont_repeat.  */

static int suppress_dont_repeat = 0;

/* Commands call this if they do not want to be repeated by null lines.  */

void
dont_repeat (void)
{
  if (suppress_dont_repeat || server_command)
    return;

  /* If we aren't reading from standard input, we are saving the last
     thing read from stdin in line and don't want to delete it.  Null
     lines won't repeat here in any case.  */
  if (instream == stdin)
    *saved_command_line = 0;
}

/* Prevent dont_repeat from working, and return a cleanup that
   restores the previous state.  */

struct cleanup *
prevent_dont_repeat (void)
{
  struct cleanup *result = make_cleanup_restore_integer (&suppress_dont_repeat);

  suppress_dont_repeat = 1;
  return result;
}


/* Read a line from the stream "instream" without command line editing.

   It prints PROMPT_ARG once at the start.
   Action is compatible with "readline", e.g. space for the result is
   malloc'd and should be freed by the caller.

   A NULL return means end of file.  */
char *
gdb_readline (char *prompt_arg)
{
  int c;
  char *result;
  int input_index = 0;
  int result_size = 80;

  if (prompt_arg)
    {
      /* Don't use a _filtered function here.  It causes the assumed
         character position to be off, since the newline we read from
         the user is not accounted for.  */
      fputs_unfiltered (prompt_arg, gdb_stdout);
      gdb_flush (gdb_stdout);
    }

  result = (char *) xmalloc (result_size);

  while (1)
    {
      /* Read from stdin if we are executing a user defined command.
         This is the right thing for prompt_for_continue, at least.  */
      c = fgetc (instream ? instream : stdin);

      if (c == EOF)
	{
	  if (input_index > 0)
	    /* The last line does not end with a newline.  Return it, and
	       if we are called again fgetc will still return EOF and
	       we'll return NULL then.  */
	    break;
	  xfree (result);
	  return NULL;
	}

      if (c == '\n')
	{
	  if (input_index > 0 && result[input_index - 1] == '\r')
	    input_index--;
	  break;
	}

      result[input_index++] = c;
      while (input_index >= result_size)
	{
	  result_size *= 2;
	  result = (char *) xrealloc (result, result_size);
	}
    }

  result[input_index++] = '\0';
  return result;
}

/* Variables which control command line editing and history
   substitution.  These variables are given default values at the end
   of this file.  */
static int command_editing_p;

/* NOTE 1999-04-29: This variable will be static again, once we modify
   gdb to use the event loop as the default command loop and we merge
   event-top.c into this file, top.c.  */

/* static */ int history_expansion_p;

static int write_history_p;
static void
show_write_history_p (struct ui_file *file, int from_tty,
		      struct cmd_list_element *c, const char *value)
{
  fprintf_filtered (file, _("Saving of the history record on exit is %s.\n"),
		    value);
}

static int history_size;
static void
show_history_size (struct ui_file *file, int from_tty,
		   struct cmd_list_element *c, const char *value)
{
  fprintf_filtered (file, _("The size of the command history is %s.\n"),
		    value);
}

static char *history_filename;
static void
show_history_filename (struct ui_file *file, int from_tty,
		       struct cmd_list_element *c, const char *value)
{
  fprintf_filtered (file, _("The filename in which to record "
			    "the command history is \"%s\".\n"),
		    value);
}

/* This is like readline(), but it has some gdb-specific behavior.
   gdb may want readline in both the synchronous and async modes during
   a single gdb invocation.  At the ordinary top-level prompt we might
   be using the async readline.  That means we can't use
   rl_pre_input_hook, since it doesn't work properly in async mode.
   However, for a secondary prompt (" >", such as occurs during a
   `define'), gdb wants a synchronous response.

   We used to call readline() directly, running it in synchronous
   mode.  But mixing modes this way is not supported, and as of
   readline 5.x it no longer works; the arrow keys come unbound during
   the synchronous call.  So we make a nested call into the event
   loop.  That's what gdb_readline_wrapper is for.  */

/* A flag set as soon as gdb_readline_wrapper_line is called; we can't
   rely on gdb_readline_wrapper_result, which might still be NULL if
   the user types Control-D for EOF.  */
static int gdb_readline_wrapper_done;

/* The result of the current call to gdb_readline_wrapper, once a newline
   is seen.  */
static char *gdb_readline_wrapper_result;

/* Any intercepted hook.  Operate-and-get-next sets this, expecting it
   to be called after the newline is processed (which will redisplay
   the prompt).  But in gdb_readline_wrapper we will not get a new
   prompt until the next call, or until we return to the event loop.
   So we disable this hook around the newline and restore it before we
   return.  */
static void (*saved_after_char_processing_hook) (void);

/* This function is called when readline has seen a complete line of
   text.  */

static void
gdb_readline_wrapper_line (char *line)
{
  gdb_assert (!gdb_readline_wrapper_done);
  gdb_readline_wrapper_result = line;
  gdb_readline_wrapper_done = 1;

  /* Prevent operate-and-get-next from acting too early.  */
  saved_after_char_processing_hook = after_char_processing_hook;
  after_char_processing_hook = NULL;

  /* Prevent parts of the prompt from being redisplayed if annotations
     are enabled, and readline's state getting out of sync.  */
  if (async_command_editing_p)
    rl_callback_handler_remove ();
}

struct gdb_readline_wrapper_cleanup
  {
    void (*handler_orig) (char *);
    int already_prompted_orig;
  };

static void
gdb_readline_wrapper_cleanup (void *arg)
{
  struct gdb_readline_wrapper_cleanup *cleanup = arg;

  rl_already_prompted = cleanup->already_prompted_orig;

  gdb_assert (input_handler == gdb_readline_wrapper_line);
  input_handler = cleanup->handler_orig;
  gdb_readline_wrapper_result = NULL;
  gdb_readline_wrapper_done = 0;

  after_char_processing_hook = saved_after_char_processing_hook;
  saved_after_char_processing_hook = NULL;

  xfree (cleanup);
}

char *
gdb_readline_wrapper (char *prompt)
{
  struct cleanup *back_to;
  struct gdb_readline_wrapper_cleanup *cleanup;
  char *retval;

  cleanup = xmalloc (sizeof (*cleanup));
  cleanup->handler_orig = input_handler;
  input_handler = gdb_readline_wrapper_line;

  cleanup->already_prompted_orig = rl_already_prompted;

  back_to = make_cleanup (gdb_readline_wrapper_cleanup, cleanup);

  /* Display our prompt and prevent double prompt display.  */
  display_gdb_prompt (prompt);
  rl_already_prompted = 1;

  if (after_char_processing_hook)
    (*after_char_processing_hook) ();
  gdb_assert (after_char_processing_hook == NULL);

  while (gdb_do_one_event () >= 0)
    if (gdb_readline_wrapper_done)
      break;

  retval = gdb_readline_wrapper_result;
  do_cleanups (back_to);
  return retval;
}


/* The current saved history number from operate-and-get-next.
   This is -1 if not valid.  */
static int operate_saved_history = -1;

/* This is put on the appropriate hook and helps operate-and-get-next
   do its work.  */
static void
gdb_rl_operate_and_get_next_completion (void)
{
  int delta = where_history () - operate_saved_history;

  /* The `key' argument to rl_get_previous_history is ignored.  */
  rl_get_previous_history (delta, 0);
  operate_saved_history = -1;

  /* readline doesn't automatically update the display for us.  */
  rl_redisplay ();

  after_char_processing_hook = NULL;
  rl_pre_input_hook = NULL;
}

/* This is a gdb-local readline command handler.  It accepts the
   current command line (like RET does) and, if this command was taken
   from the history, arranges for the next command in the history to
   appear on the command line when the prompt returns.
   We ignore the arguments.  */
static int
gdb_rl_operate_and_get_next (int count, int key)
{
  int where;

  /* Use the async hook.  */
  after_char_processing_hook = gdb_rl_operate_and_get_next_completion;

  /* Find the current line, and find the next line to use.  */
  where = where_history();

  /* FIXME: kettenis/20020817: max_input_history is renamed into
     history_max_entries in readline-4.2.  When we do a new readline
     import, we should probably change it here too, even though
     readline maintains backwards compatibility for now by still
     defining max_input_history.  */
  if ((history_is_stifled () && (history_length >= max_input_history)) ||
      (where >= history_length - 1))
    operate_saved_history = where;
  else
    operate_saved_history = where + 1;

  return rl_newline (1, key);
}

/* Read one line from the command input stream `instream'
   into the local static buffer `linebuffer' (whose current length
   is `linelength').
   The buffer is made bigger as necessary.
   Returns the address of the start of the line.

   NULL is returned for end of file.

   *If* the instream == stdin & stdin is a terminal, the line read
   is copied into the file line saver (global var char *line,
   length linesize) so that it can be duplicated.

   This routine either uses fancy command line editing or
   simple input as the user has requested.  */

char *
command_line_input (char *prompt_arg, int repeat, char *annotation_suffix)
{
  static char *linebuffer = 0;
  static unsigned linelength = 0;
  char *p;
  char *p1;
  char *rl;
  char *local_prompt = prompt_arg;
  char *nline;
  char got_eof = 0;

  /* The annotation suffix must be non-NULL.  */
  if (annotation_suffix == NULL)
    annotation_suffix = "";

  if (annotation_level > 1 && instream == stdin)
    {
      local_prompt = alloca ((prompt_arg == NULL ? 0 : strlen (prompt_arg))
			     + strlen (annotation_suffix) + 40);
      if (prompt_arg == NULL)
	local_prompt[0] = '\0';
      else
	strcpy (local_prompt, prompt_arg);
      strcat (local_prompt, "\n\032\032");
      strcat (local_prompt, annotation_suffix);
      strcat (local_prompt, "\n");
    }

  if (linebuffer == 0)
    {
      linelength = 80;
      linebuffer = (char *) xmalloc (linelength);
    }

  p = linebuffer;

  /* Control-C quits instantly if typed while in this loop
     since it should not wait until the user types a newline.  */
  immediate_quit++;
#ifdef STOP_SIGNAL
  if (job_control)
    signal (STOP_SIGNAL, handle_stop_sig);
#endif

  while (1)
    {
      /* Make sure that all output has been output.  Some machines may
         let you get away with leaving out some of the gdb_flush, but
         not all.  */
      wrap_here ("");
      gdb_flush (gdb_stdout);
      gdb_flush (gdb_stderr);

      if (source_file_name != NULL)
	++source_line_number;

      if (annotation_level > 1 && instream == stdin)
	{
	  puts_unfiltered ("\n\032\032pre-");
	  puts_unfiltered (annotation_suffix);
	  puts_unfiltered ("\n");
	}

      /* Don't use fancy stuff if not talking to stdin.  */
      if (deprecated_readline_hook && input_from_terminal_p ())
	{
	  rl = (*deprecated_readline_hook) (local_prompt);
	}
      else if (command_editing_p && input_from_terminal_p ())
	{
	  rl = gdb_readline_wrapper (local_prompt);
	}
      else
	{
	  rl = gdb_readline (local_prompt);
	}

      if (annotation_level > 1 && instream == stdin)
	{
	  puts_unfiltered ("\n\032\032post-");
	  puts_unfiltered (annotation_suffix);
	  puts_unfiltered ("\n");
	}

      if (!rl || rl == (char *) EOF)
	{
	  got_eof = 1;
	  break;
	}
      if (strlen (rl) + 1 + (p - linebuffer) > linelength)
	{
	  linelength = strlen (rl) + 1 + (p - linebuffer);
	  nline = (char *) xrealloc (linebuffer, linelength);
	  p += nline - linebuffer;
	  linebuffer = nline;
	}
      p1 = rl;
      /* Copy line.  Don't copy null at end.  (Leaves line alone
         if this was just a newline).  */
      while (*p1)
	*p++ = *p1++;

      xfree (rl);		/* Allocated in readline.  */

      if (p == linebuffer || *(p - 1) != '\\')
	break;

      p--;			/* Put on top of '\'.  */
      local_prompt = (char *) 0;
    }

#ifdef STOP_SIGNAL
  if (job_control)
    signal (STOP_SIGNAL, SIG_DFL);
#endif
  immediate_quit--;

  if (got_eof)
    return NULL;

#define SERVER_COMMAND_LENGTH 7
  server_command =
    (p - linebuffer > SERVER_COMMAND_LENGTH)
    && strncmp (linebuffer, "server ", SERVER_COMMAND_LENGTH) == 0;
  if (server_command)
    {
      /* Note that we don't set `line'.  Between this and the check in
         dont_repeat, this insures that repeating will still do the
         right thing.  */
      *p = '\0';
      return linebuffer + SERVER_COMMAND_LENGTH;
    }

  /* Do history expansion if that is wished.  */
  if (history_expansion_p && instream == stdin
      && ISATTY (instream))
    {
      char *history_value;
      int expanded;

      *p = '\0';		/* Insert null now.  */
      expanded = history_expand (linebuffer, &history_value);
      if (expanded)
	{
	  /* Print the changes.  */
	  printf_unfiltered ("%s\n", history_value);

	  /* If there was an error, call this function again.  */
	  if (expanded < 0)
	    {
	      xfree (history_value);
	      return command_line_input (prompt_arg, repeat,
					 annotation_suffix);
	    }
	  if (strlen (history_value) > linelength)
	    {
	      linelength = strlen (history_value) + 1;
	      linebuffer = (char *) xrealloc (linebuffer, linelength);
	    }
	  strcpy (linebuffer, history_value);
	  p = linebuffer + strlen (linebuffer);
	}
      xfree (history_value);
    }

  /* If we just got an empty line, and that is supposed to repeat the
     previous command, return the value in the global buffer.  */
  if (repeat && p == linebuffer)
    return saved_command_line;
  for (p1 = linebuffer; *p1 == ' ' || *p1 == '\t'; p1++);
  if (repeat && !*p1)
    return saved_command_line;

  *p = 0;

  /* Add line to history if appropriate.  */
  if (instream == stdin
      && ISATTY (stdin) && *linebuffer)
    add_history (linebuffer);

  /* Note: lines consisting solely of comments are added to the command
     history.  This is useful when you type a command, and then
     realize you don't want to execute it quite yet.  You can comment
     out the command and then later fetch it from the value history
     and remove the '#'.  The kill ring is probably better, but some
     people are in the habit of commenting things out.  */
  if (*p1 == '#')
    *p1 = '\0';			/* Found a comment.  */

  /* Save into global buffer if appropriate.  */
  if (repeat)
    {
      if (linelength > saved_command_line_size)
	{
	  saved_command_line = xrealloc (saved_command_line, linelength);
	  saved_command_line_size = linelength;
	}
      strcpy (saved_command_line, linebuffer);
      return saved_command_line;
    }

  return linebuffer;
}

/* Print the GDB banner.  */
void
print_gdb_version (struct ui_file *stream)
{
  /* From GNU coding standards, first line is meant to be easy for a
     program to parse, and is just canonical program name and version
     number, which starts after last space.  */

  fprintf_filtered (stream, "GNU gdb %s%s\n", PKGVERSION, version);

  /* Second line is a copyright notice.  */

  fprintf_filtered (stream,
		    "Copyright (C) 2012 Free Software Foundation, Inc.\n");

  /* Following the copyright is a brief statement that the program is
     free software, that users are free to copy and change it on
     certain conditions, that it is covered by the GNU GPL, and that
     there is no warranty.  */

  fprintf_filtered (stream, "\
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>\
\nThis is free software: you are free to change and redistribute it.\n\
There is NO WARRANTY, to the extent permitted by law.  Type \"show copying\"\n\
and \"show warranty\" for details.\n");

  /* After the required info we print the configuration information.  */

  fprintf_filtered (stream, "This GDB was configured as \"");
  if (strcmp (host_name, target_name) != 0)
    {
      fprintf_filtered (stream, "--host=%s --target=%s",
			host_name, target_name);
    }
  else
    {
      fprintf_filtered (stream, "%s", host_name);
    }
  fprintf_filtered (stream, "\".");

  if (REPORT_BUGS_TO[0])
    {
      fprintf_filtered (stream, 
			_("\nFor bug reporting instructions, please see:\n"));
      fprintf_filtered (stream, "%s.", REPORT_BUGS_TO);
    }
}


/* The current top level prompt, settable with "set prompt", and/or
   with the python `gdb.prompt_hook' hook.  */
static char *top_prompt;

/* Access method for the GDB prompt string.  */

char *
get_prompt (void)
{
  return top_prompt;
}

/* Set method for the GDB prompt string.  */

void
set_prompt (const char *s)
{
  char *p = xstrdup (s);

  xfree (top_prompt);
  top_prompt = p;
}


struct qt_args
{
  char *args;
  int from_tty;
};

/* Callback for iterate_over_inferiors.  Kills or detaches the given
   inferior, depending on how we originally gained control of it.  */

static int
kill_or_detach (struct inferior *inf, void *args)
{
  struct qt_args *qt = args;
  struct thread_info *thread;

  if (inf->pid == 0)
    return 0;

  thread = any_thread_of_process (inf->pid);
  if (thread != NULL)
    {
      switch_to_thread (thread->ptid);

      /* Leave core files alone.  */
      if (target_has_execution)
	{
	  if (inf->attach_flag)
	    target_detach (qt->args, qt->from_tty);
	  else
	    target_kill ();
	}
    }

  return 0;
}

/* Callback for iterate_over_inferiors.  Prints info about what GDB
   will do to each inferior on a "quit".  ARG points to a struct
   ui_out where output is to be collected.  */

static int
print_inferior_quit_action (struct inferior *inf, void *arg)
{
  struct ui_file *stb = arg;

  if (inf->pid == 0)
    return 0;

  if (inf->attach_flag)
    fprintf_filtered (stb,
		      _("\tInferior %d [%s] will be detached.\n"), inf->num,
		      target_pid_to_str (pid_to_ptid (inf->pid)));
  else
    fprintf_filtered (stb,
		      _("\tInferior %d [%s] will be killed.\n"), inf->num,
		      target_pid_to_str (pid_to_ptid (inf->pid)));

  return 0;
}

/* If necessary, make the user confirm that we should quit.  Return
   non-zero if we should quit, zero if we shouldn't.  */

int
quit_confirm (void)
{
  struct ui_file *stb;
  struct cleanup *old_chain;
  char *str;
  int qr;

  /* Don't even ask if we're only debugging a core file inferior.  */
  if (!have_live_inferiors ())
    return 1;

  /* Build the query string as a single string.  */
  stb = mem_fileopen ();
  old_chain = make_cleanup_ui_file_delete (stb);

  /* This is something of a hack.  But there's no reliable way to see
     if a GUI is running.  The `use_windows' variable doesn't cut
     it.  */
  if (deprecated_init_ui_hook)
    fprintf_filtered (stb, _("A debugging session is active.\n"
			     "Do you still want to close the debugger?"));
  else
    {
      fprintf_filtered (stb, _("A debugging session is active.\n\n"));
      iterate_over_inferiors (print_inferior_quit_action, stb);
      fprintf_filtered (stb, _("\nQuit anyway? "));
    }

  str = ui_file_xstrdup (stb, NULL);
  make_cleanup (xfree, str);

  qr = query ("%s", str);
  do_cleanups (old_chain);
  return qr;
}

/* Helper routine for quit_force that requires error handling.  */

static int
quit_target (void *arg)
{
  struct qt_args *qt = (struct qt_args *)arg;

  /* Kill or detach all inferiors.  */
  iterate_over_inferiors (kill_or_detach, qt);

  /* Give all pushed targets a chance to do minimal cleanup, and pop
     them all out.  */
  pop_all_targets (1);

  /* Save the history information if it is appropriate to do so.  */
  if (write_history_p && history_filename)
    write_history (history_filename);

  do_final_cleanups (all_cleanups ());    /* Do any final cleanups before
					     exiting.  */
  return 0;
}

/* Quit without asking for confirmation.  */

void
quit_force (char *args, int from_tty)
{
  int exit_code = 0;
  struct qt_args qt;

  /* An optional expression may be used to cause gdb to terminate with the 
     value of that expression.  */
  if (args)
    {
      struct value *val = parse_and_eval (args);

      exit_code = (int) value_as_long (val);
    }
  else if (return_child_result)
    exit_code = return_child_result_value;

  qt.args = args;
  qt.from_tty = from_tty;

  /* We want to handle any quit errors and exit regardless.  */
  catch_errors (quit_target, &qt,
	        "Quitting: ", RETURN_MASK_ALL);

  exit (exit_code);
}

/* Returns whether GDB is running on a terminal and input is
   currently coming from that terminal.  */

int
input_from_terminal_p (void)
{
  if (batch_flag)
    return 0;

  if (gdb_has_a_terminal () && instream == stdin)
    return 1;

  /* If INSTREAM is unset, and we are not in a user command, we
     must be in Insight.  That's like having a terminal, for our
     purposes.  */
  if (instream == NULL && !in_user_command)
    return 1;

  return 0;
}

static void
dont_repeat_command (char *ignored, int from_tty)
{
  /* Can't call dont_repeat here because we're not necessarily reading
     from stdin.  */
  *saved_command_line = 0;
}

/* Functions to manipulate command line editing control variables.  */

/* Number of commands to print in each call to show_commands.  */
#define Hist_print 10
void
show_commands (char *args, int from_tty)
{
  /* Index for history commands.  Relative to history_base.  */
  int offset;

  /* Number of the history entry which we are planning to display next.
     Relative to history_base.  */
  static int num = 0;

  /* The first command in the history which doesn't exist (i.e. one more
     than the number of the last command).  Relative to history_base.  */
  int hist_len;

  /* Print out some of the commands from the command history.  */
  /* First determine the length of the history list.  */
  hist_len = history_size;
  for (offset = 0; offset < history_size; offset++)
    {
      if (!history_get (history_base + offset))
	{
	  hist_len = offset;
	  break;
	}
    }

  if (args)
    {
      if (args[0] == '+' && args[1] == '\0')
	/* "info editing +" should print from the stored position.  */
	;
      else
	/* "info editing <exp>" should print around command number <exp>.  */
	num = (parse_and_eval_long (args) - history_base) - Hist_print / 2;
    }
  /* "show commands" means print the last Hist_print commands.  */
  else
    {
      num = hist_len - Hist_print;
    }

  if (num < 0)
    num = 0;

  /* If there are at least Hist_print commands, we want to display the last
     Hist_print rather than, say, the last 6.  */
  if (hist_len - num < Hist_print)
    {
      num = hist_len - Hist_print;
      if (num < 0)
	num = 0;
    }

  for (offset = num; offset < num + Hist_print && offset < hist_len; offset++)
    {
      printf_filtered ("%5d  %s\n", history_base + offset,
		       (history_get (history_base + offset))->line);
    }

  /* The next command we want to display is the next one that we haven't
     displayed yet.  */
  num += Hist_print;

  /* If the user repeats this command with return, it should do what
     "show commands +" does.  This is unnecessary if arg is null,
     because "show commands +" is not useful after "show commands".  */
  if (from_tty && args)
    {
      args[0] = '+';
      args[1] = '\0';
    }
}

/* Called by do_setshow_command.  */
static void
set_history_size_command (char *args, int from_tty, struct cmd_list_element *c)
{
  if (history_size == INT_MAX)
    unstifle_history ();
  else if (history_size >= 0)
    stifle_history (history_size);
  else
    {
      history_size = INT_MAX;
      error (_("History size must be non-negative"));
    }
}

void
set_history (char *args, int from_tty)
{
  printf_unfiltered (_("\"set history\" must be followed "
		       "by the name of a history subcommand.\n"));
  help_list (sethistlist, "set history ", -1, gdb_stdout);
}

void
show_history (char *args, int from_tty)
{
  cmd_show_list (showhistlist, from_tty, "");
}

int info_verbose = 0;		/* Default verbose msgs off.  */

/* Called by do_setshow_command.  An elaborate joke.  */
void
set_verbose (char *args, int from_tty, struct cmd_list_element *c)
{
  char *cmdname = "verbose";
  struct cmd_list_element *showcmd;

  showcmd = lookup_cmd_1 (&cmdname, showlist, NULL, 1);
  gdb_assert (showcmd != NULL && showcmd != CMD_LIST_AMBIGUOUS);

  if (info_verbose)
    {
      c->doc = "Set verbose printing of informational messages.";
      showcmd->doc = "Show verbose printing of informational messages.";
    }
  else
    {
      c->doc = "Set verbosity.";
      showcmd->doc = "Show verbosity.";
    }
}

/* Init the history buffer.  Note that we are called after the init file(s)
   have been read so that the user can change the history file via his
   .gdbinit file (for instance).  The GDBHISTFILE environment variable
   overrides all of this.  */

void
init_history (void)
{
  char *tmpenv;

  tmpenv = getenv ("HISTSIZE");
  if (tmpenv)
    history_size = atoi (tmpenv);
  else if (!history_size)
    history_size = 256;

  stifle_history (history_size);

  tmpenv = getenv ("GDBHISTFILE");
  if (tmpenv)
    history_filename = xstrdup (tmpenv);
  else if (!history_filename)
    {
      /* We include the current directory so that if the user changes
         directories the file written will be the same as the one
         that was read.  */
#ifdef __MSDOS__
      /* No leading dots in file names are allowed on MSDOS.  */
      history_filename = concat (current_directory, "/_gdb_history",
				 (char *)NULL);
#else
      history_filename = concat (current_directory, "/.gdb_history",
				 (char *)NULL);
#endif
    }
  read_history (history_filename);
}

static void
show_prompt (struct ui_file *file, int from_tty,
	     struct cmd_list_element *c, const char *value)
{
  fprintf_filtered (file, _("Gdb's prompt is \"%s\".\n"), value);
}

static void
show_async_command_editing_p (struct ui_file *file, int from_tty,
			      struct cmd_list_element *c, const char *value)
{
  fprintf_filtered (file, _("Editing of command lines as "
			    "they are typed is %s.\n"),
		    value);
}

static void
show_annotation_level (struct ui_file *file, int from_tty,
		       struct cmd_list_element *c, const char *value)
{
  fprintf_filtered (file, _("Annotation_level is %s.\n"), value);
}

static void
show_exec_done_display_p (struct ui_file *file, int from_tty,
			  struct cmd_list_element *c, const char *value)
{
  fprintf_filtered (file, _("Notification of completion for "
			    "asynchronous execution commands is %s.\n"),
		    value);
}

/* "set" command for the gdb_datadir configuration variable.  */

static void
set_gdb_datadir (char *args, int from_tty, struct cmd_list_element *c)
{
  observer_notify_gdb_datadir_changed ();
}

static void
init_main (void)
{
  /* Initialize the prompt to a simple "(gdb) " prompt or to whatever
     the DEFAULT_PROMPT is.  */
  set_prompt (DEFAULT_PROMPT);

  /* Set things up for annotation_level > 1, if the user ever decides
     to use it.  */
  async_annotation_suffix = "prompt";

  /* Set the important stuff up for command editing.  */
  command_editing_p = 1;
  history_expansion_p = 0;
  write_history_p = 0;

  /* Setup important stuff for command line editing.  */
  rl_completion_word_break_hook = gdb_completion_word_break_characters;
  rl_completion_entry_function = readline_line_completion_function;
  rl_completer_word_break_characters = default_word_break_characters ();
  rl_completer_quote_characters = get_gdb_completer_quote_characters ();
  rl_readline_name = "gdb";
  rl_terminal_name = getenv ("TERM");

  /* The name for this defun comes from Bash, where it originated.
     15 is Control-o, the same binding this function has in Bash.  */
  rl_add_defun ("operate-and-get-next", gdb_rl_operate_and_get_next, 15);

  add_setshow_string_cmd ("prompt", class_support,
			  &top_prompt,
			  _("Set gdb's prompt"),
			  _("Show gdb's prompt"),
			  NULL, NULL,
			  show_prompt,
			  &setlist, &showlist);

  add_com ("dont-repeat", class_support, dont_repeat_command, _("\
Don't repeat this command.\nPrimarily \
used inside of user-defined commands that should not be repeated when\n\
hitting return."));

  add_setshow_boolean_cmd ("editing", class_support,
			   &async_command_editing_p, _("\
Set editing of command lines as they are typed."), _("\
Show editing of command lines as they are typed."), _("\
Use \"on\" to enable the editing, and \"off\" to disable it.\n\
Without an argument, command line editing is enabled.  To edit, use\n\
EMACS-like or VI-like commands like control-P or ESC."),
			   set_async_editing_command,
			   show_async_command_editing_p,
			   &setlist, &showlist);

  add_setshow_boolean_cmd ("save", no_class, &write_history_p, _("\
Set saving of the history record on exit."), _("\
Show saving of the history record on exit."), _("\
Use \"on\" to enable the saving, and \"off\" to disable it.\n\
Without an argument, saving is enabled."),
			   NULL,
			   show_write_history_p,
			   &sethistlist, &showhistlist);

  add_setshow_integer_cmd ("size", no_class, &history_size, _("\
Set the size of the command history,"), _("\
Show the size of the command history,"), _("\
ie. the number of previous commands to keep a record of."),
			   set_history_size_command,
			   show_history_size,
			   &sethistlist, &showhistlist);

  add_setshow_filename_cmd ("filename", no_class, &history_filename, _("\
Set the filename in which to record the command history"), _("\
Show the filename in which to record the command history"), _("\
(the list of previous commands of which a record is kept)."),
			    NULL,
			    show_history_filename,
			    &sethistlist, &showhistlist);

  add_setshow_boolean_cmd ("confirm", class_support, &confirm, _("\
Set whether to confirm potentially dangerous operations."), _("\
Show whether to confirm potentially dangerous operations."), NULL,
			   NULL,
			   show_confirm,
			   &setlist, &showlist);

  add_setshow_zinteger_cmd ("annotate", class_obscure, &annotation_level, _("\
Set annotation_level."), _("\
Show annotation_level."), _("\
0 == normal;     1 == fullname (for use when running under emacs)\n\
2 == output annotated suitably for use by programs that control GDB."),
			    NULL,
			    show_annotation_level,
			    &setlist, &showlist);

  add_setshow_boolean_cmd ("exec-done-display", class_support,
			   &exec_done_display_p, _("\
Set notification of completion for asynchronous execution commands."), _("\
Show notification of completion for asynchronous execution commands."), _("\
Use \"on\" to enable the notification, and \"off\" to disable it."),
			   NULL,
			   show_exec_done_display_p,
			   &setlist, &showlist);

  add_setshow_filename_cmd ("data-directory", class_maintenance,
                           &gdb_datadir, _("Set GDB's data directory."),
                           _("Show GDB's data directory."),
                           _("\
When set, GDB uses the specified path to search for data files."),
                           set_gdb_datadir, NULL,
                           &setlist,
                           &showlist);
}

void
gdb_init (char *argv0)
{
  if (pre_init_ui_hook)
    pre_init_ui_hook ();

  /* Run the init function of each source file.  */

#ifdef __MSDOS__
  /* Make sure we return to the original directory upon exit, come
     what may, since the OS doesn't do that for us.  */
  make_final_cleanup (do_chdir_cleanup, xstrdup (current_directory));
#endif

  init_cmd_lists ();	    /* This needs to be done first.  */
  initialize_targets ();    /* Setup target_terminal macros for utils.c.  */
  initialize_utils ();	    /* Make errors and warnings possible.  */

  /* Here is where we call all the _initialize_foo routines.  */
  initialize_all_files ();

  /* This creates the current_program_space.  Do this after all the
     _initialize_foo routines have had a chance to install their
     per-sspace data keys.  Also do this before
     initialize_current_architecture is called, because it accesses
     exec_bfd of the current program space.  */
  initialize_progspace ();
  initialize_inferiors ();
  initialize_current_architecture ();
  init_cli_cmds();
  init_main ();			/* But that omits this file!  Do it now.  */

  initialize_stdin_serial ();

  async_init_signals ();

  /* We need a default language for parsing expressions, so simple
     things like "set width 0" won't fail if no language is explicitly
     set in a config file or implicitly set by reading an executable
     during startup.  */
  set_language (language_c);
  expected_language = current_language;	/* Don't warn about the change.  */

  /* Allow another UI to initialize.  If the UI fails to initialize,
     and it wants GDB to revert to the CLI, it should clear
     deprecated_init_ui_hook.  */
  if (deprecated_init_ui_hook)
    deprecated_init_ui_hook (argv0);

#ifdef HAVE_PYTHON
  /* Python initialization can require various commands to be
     installed.  For example "info pretty-printer" needs the "info"
     prefix to be installed.  Keep things simple and just do final
     python initialization here.  */
  finish_python_initialization ();
#endif
}