aboutsummaryrefslogtreecommitdiff
path: root/gdb/command.c
blob: 36661be44a78d2fb5f95714b9d692d40c80a3918 (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
/* Library for reading command lines and decoding commands.
   Copyright (C) 1986, 1989, 1990 Free Software Foundation, Inc.

   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 1, 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, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include <stdio.h>
#include "defs.h"
#include "command.h"
#include "symtab.h"
#include "value.h"
#include <ctype.h>
#include <string.h>

extern char *getenv ();

/* Add element named NAME to command list *LIST.
   FUN should be the function to execute the command;
   it will get a character string as argument, with leading
   and trailing blanks already eliminated.

   DOC is a documentation string for the command.
   Its first line should be a complete sentence.
   It should start with ? for a command that is an abbreviation
   or with * for a command that most users don't need to know about.  */

struct cmd_list_element *
add_cmd (name, class, fun, doc, list)
     char *name;
     enum command_class class;
     void (*fun) ();
     char *doc;
     struct cmd_list_element **list;
{
  register struct cmd_list_element *c
    = (struct cmd_list_element *) xmalloc (sizeof (struct cmd_list_element));

  delete_cmd (name, list);
  c->next = *list;
  c->name = name;
  c->class = class;
  c->function = fun;
  c->doc = doc;
  c->prefixlist = 0;
  c->prefixname = (char *)NULL;
  c->allow_unknown = 0;
  c->abbrev_flag = 0;
  c->aux = 0;
  c->type = not_set_cmd;
  c->completer = make_symbol_completion_list;
  c->var = 0;
  c->var_type = var_boolean;
  c->user_commands = 0;
  *list = c;
  return c;
}

/* Same as above, except that the abbrev_flag is set. */

struct cmd_list_element *
add_abbrev_cmd (name, class, fun, doc, list)
     char *name;
     enum command_class class;
     void (*fun) ();
     char *doc;
     struct cmd_list_element **list;
{
  register struct cmd_list_element *c
    = add_cmd (name, class, fun, doc, list);

  c->abbrev_flag = 1;
  return c;
}

struct cmd_list_element *
add_alias_cmd (name, oldname, class, abbrev_flag, list)
     char *name;
     char *oldname;
     enum command_class class;
     int abbrev_flag;
     struct cmd_list_element **list;
{
  /* Must do this since lookup_cmd tries to side-effect its first arg */
  char *copied_name;
  register struct cmd_list_element *old;
  register struct cmd_list_element *c;
  copied_name = (char *) alloca (strlen (oldname) + 1);
  strcpy (copied_name, oldname);
  old  = lookup_cmd (&copied_name, *list, "", 1, 1);

  if (old == 0)
    {
      delete_cmd (name, list);
      return 0;
    }

  c = add_cmd (name, class, old->function, old->doc, list);
  c->prefixlist = old->prefixlist;
  c->prefixname = old->prefixname;
  c->allow_unknown = old->allow_unknown;
  c->abbrev_flag = abbrev_flag;
  c->aux = old->aux;
  return c;
}

/* Like add_cmd but adds an element for a command prefix:
   a name that should be followed by a subcommand to be looked up
   in another command list.  PREFIXLIST should be the address
   of the variable containing that list.  */

struct cmd_list_element *
add_prefix_cmd (name, class, fun, doc, prefixlist, prefixname,
		allow_unknown, list)
     char *name;
     enum command_class class;
     void (*fun) ();
     char *doc;
     struct cmd_list_element **prefixlist;
     char *prefixname;
     int allow_unknown;
     struct cmd_list_element **list;
{
  register struct cmd_list_element *c = add_cmd (name, class, fun, doc, list);
  c->prefixlist = prefixlist;
  c->prefixname = prefixname;
  c->allow_unknown = allow_unknown;
  return c;
}

/* Like add_prefix_cmd butsets the abbrev_flag on the new command. */
   
struct cmd_list_element *
add_abbrev_prefix_cmd (name, class, fun, doc, prefixlist, prefixname,
		allow_unknown, list)
     char *name;
     enum command_class class;
     void (*fun) ();
     char *doc;
     struct cmd_list_element **prefixlist;
     char *prefixname;
     int allow_unknown;
     struct cmd_list_element **list;
{
  register struct cmd_list_element *c = add_cmd (name, class, fun, doc, list);
  c->prefixlist = prefixlist;
  c->prefixname = prefixname;
  c->allow_unknown = allow_unknown;
  c->abbrev_flag = 1;
  return c;
}

/* ARGSUSED */
void
not_just_help_class_command (args, from_tty, c)
     char *args;
     int from_tty;
     struct cmd_list_element *c;
{
}

/* Add element named NAME to command list LIST (the list for set
   or some sublist thereof).
   CLASS is as in add_cmd.
   VAR_TYPE is the kind of thing we are setting.
   VAR is address of the variable being controlled by this command.
   DOC is the documentation string.  */
struct cmd_list_element *
add_set_cmd (name, class, var_type, var, doc, list)
     char *name;
     enum command_class class;
     var_types var_type;
     char *var;
     char *doc;
     struct cmd_list_element **list;
{
  /* For set/show, we have to call do_setshow_command
     differently than an ordinary function (take commandlist as
     well as arg), so the function field isn't helpful.  However,
     function == NULL means that it's a help class, so set the function
     to not_just_help_class_command.  */
  struct cmd_list_element *c
    = add_cmd (name, class, not_just_help_class_command, doc, list);

  c->type = set_cmd;
  c->var_type = var_type;
  c->var = var;
  return c;
}

/* Where SETCMD has already been added, add the corresponding show
   command to LIST and return a pointer to it.  */
struct cmd_list_element *
add_show_from_set (setcmd, list)
     struct cmd_list_element *setcmd;
     struct cmd_list_element **list;
{
  struct cmd_list_element *showcmd =
    (struct cmd_list_element *) xmalloc (sizeof (struct cmd_list_element));

  bcopy (setcmd, showcmd, sizeof (struct cmd_list_element));
  delete_cmd (showcmd->name, list);
  showcmd->type = show_cmd;
  
  /* Replace "set " at start of docstring with "show ".  */
  if (setcmd->doc[0] == 'S' && setcmd->doc[1] == 'e'
      && setcmd->doc[2] == 't' && setcmd->doc[3] == ' ')
    showcmd->doc = concat ("Show ", setcmd->doc + 4, "");
  else
    fprintf (stderr, "GDB internal error: Bad docstring for set command\n");
  
  showcmd->next = *list;
  *list = showcmd;
  return showcmd;
}

/* Remove the command named NAME from the command list.  */

void
delete_cmd (name, list)
     char *name;
     struct cmd_list_element **list;
{
  register struct cmd_list_element *c;
  struct cmd_list_element *p;

  while (*list && !strcmp ((*list)->name, name))
    {
      p = (*list)->next;
      free (*list);
      *list = p;
    }

  if (*list)
    for (c = *list; c->next;)
      {
	if (!strcmp (c->next->name, name))
	  {
	    p = c->next->next;
	    free (c->next);
	    c->next = p;
	  }
	else
	  c = c->next;
      }
}

/* This command really has to deal with two things:
 *     1) I want documentation on *this string* (usually called by
 * "help commandname").
 *     2) I want documentation on *this list* (usually called by
 * giving a command that requires subcommands.  Also called by saying
 * just "help".)
 *
 *   I am going to split this into two seperate comamnds, help_cmd and
 * help_list. 
 */

void
help_cmd (command, stream)
     char *command;
     FILE *stream;
{
  struct cmd_list_element *c;
  extern struct cmd_list_element *cmdlist;

  if (!command)
    {
      help_list (cmdlist, "", all_classes, stream);
      return;
    }

  c = lookup_cmd (&command, cmdlist, "", 0, 0);

  if (c == 0)
    return;

  /* There are three cases here.
     If c->prefixlist is nonzero, we have a prefix command.
     Print its documentation, then list its subcommands.
     
     If c->function is nonzero, we really have a command.
     Print its documentation and return.
     
     If c->function is zero, we have a class name.
     Print its documentation (as if it were a command)
     and then set class to the number of this class
     so that the commands in the class will be listed.  */

  fputs_filtered (c->doc, stream);
  fputs_filtered ("\n", stream);

  if (c->prefixlist == 0 && c->function != 0)
    return;
  fprintf_filtered (stream, "\n");

  /* If this is a prefix command, print it's subcommands */
  if (c->prefixlist)
    help_list (*c->prefixlist, c->prefixname, all_commands, stream);

  /* If this is a class name, print all of the commands in the class */
  if (c->function == 0)
    help_list (cmdlist, "", c->class, stream);
}

/*
 * Get a specific kind of help on a command list.
 *
 * LIST is the list.
 * CMDTYPE is the prefix to use in the title string.
 * CLASS is the class with which to list the nodes of this list (see
 * documentation for help_cmd_list below),  As usual, ALL_COMMANDS for
 * everything, ALL_CLASSES for just classes, and non-negative for only things
 * in a specific class.
 * and STREAM is the output stream on which to print things.
 * If you call this routine with a class >= 0, it recurses.
 */
void
help_list (list, cmdtype, class, stream)
     struct cmd_list_element *list;
     char *cmdtype;
     enum command_class class;
     FILE *stream;
{
  int len;
  char *cmdtype1, *cmdtype2;
  
  /* If CMDTYPE is "foo ", CMDTYPE1 gets " foo" and CMDTYPE2 gets "foo sub"  */
  len = strlen (cmdtype);
  cmdtype1 = (char *) alloca (len + 1);
  cmdtype1[0] = 0;
  cmdtype2 = (char *) alloca (len + 4);
  cmdtype2[0] = 0;
  if (len)
    {
      cmdtype1[0] = ' ';
      strncpy (cmdtype1 + 1, cmdtype, len - 1);
      cmdtype1[len] = 0;
      strncpy (cmdtype2, cmdtype, len - 1);
      strcpy (cmdtype2 + len - 1, " sub");
    }

  if (class == all_classes)
    fprintf_filtered (stream, "List of classes of %scommands:\n\n", cmdtype2);
  else
    fprintf_filtered (stream, "List of %scommands:\n\n", cmdtype2);

  help_cmd_list (list, class, cmdtype, (int)class >= 0, stream);

  if (class == all_classes)
    fprintf_filtered (stream, "\n\
Type \"help%s\" followed by a class name for a list of commands in that class.",
	     cmdtype1);

  fprintf_filtered (stream, "\n\
Type \"help%s\" followed by %scommand name for full documentation.\n\
Command name abbreviations are allowed if unambiguous.\n",
	   cmdtype1, cmdtype2);
}
     
/* Print only the first line of STR on STREAM.  */
static void
print_doc_line (stream, str)
     FILE *stream;
     char *str;
{
  static char *line_buffer = 0;
  static int line_size;
  register char *p;

  if (!line_buffer)
    {
      line_size = 80;
      line_buffer = (char *) xmalloc (line_size);
    }

  p = str;
  while (*p && *p != '\n' && *p != '.' && *p != ',')
    p++;
  if (p - str > line_size - 1)
    {
      line_size = p - str + 1;
      free (line_buffer);
      line_buffer = (char *) xmalloc (line_size);
    }
  strncpy (line_buffer, str, p - str);
  line_buffer[p - str] = '\0';
  if (islower (line_buffer[0]))
    line_buffer[0] = toupper (line_buffer[0]);
  fputs_filtered (line_buffer, stream);
}

/*
 * Implement a help command on command list LIST.
 * RECURSE should be non-zero if this should be done recursively on
 * all sublists of LIST.
 * PREFIX is the prefix to print before each command name.
 * STREAM is the stream upon which the output should be written.
 * CLASS should be:
 *	A non-negative class number to list only commands in that
 * class.
 *	ALL_COMMANDS to list all commands in list.
 *	ALL_CLASSES  to list all classes in list.
 *
 *   Note that RECURSE will be active on *all* sublists, not just the
 * ones seclected by the criteria above (ie. the selection mechanism
 * is at the low level, not the high-level).
 */
void
help_cmd_list (list, class, prefix, recurse, stream)
     struct cmd_list_element *list;
     enum command_class class;
     char *prefix;
     int recurse;
     FILE *stream;
{
  register struct cmd_list_element *c;

  for (c = list; c; c = c->next)
    {
      if (c->abbrev_flag == 0 &&
	  (class == all_commands
	  || (class == all_classes && c->function == 0)
	  || (class == c->class && c->function != 0)))
	{
	  fprintf_filtered (stream, "%s%s -- ", prefix, c->name);
	  print_doc_line (stream, c->doc);
	  fputs_filtered ("\n", stream);
	}
      if (recurse
	  && c->prefixlist != 0
	  && c->abbrev_flag == 0)
	help_cmd_list (*c->prefixlist, class, c->prefixname, 1, stream);
    }
}

/* This routine takes a line of TEXT and a CLIST in which to
   start the lookup.  When it returns it will have incremented the text
   pointer past the section of text it matched, set *RESULT_LIST to
   the list in which the last word was matched, and will return the
   cmd list element which the text matches.  It will return 0 if no
   match at all was possible.  It will return -1 if ambigous matches are
   possible; in this case *RESULT_LIST will be set to the list in which
   there are ambiguous choices (and text will be set to the ambiguous
   text string).

   It does no error reporting whatsoever; control will always return
   to the superior routine.

   In the case of an ambiguous return (-1), *RESULT_LIST will be set to
   point at the prefix_command (ie. the best match) *or* (special
   case) will be 0 if no prefix command was ever found.  For example,
   in the case of "info a", "info" matches without ambiguity, but "a"
   could be "args" or "address", so *RESULT_LIST is set to
   the cmd_list_element for "info".  So in this case
   result list should not be interpeted as a pointer to the beginning
   of a list; it simply points to a specific command.

   If RESULT_LIST is NULL, don't set *RESULT_LIST (but don't otherwise
   affect the operation).

   This routine does *not* modify the text pointed to by TEXT.
   
   If IGNORE_HELP_CLASSES is nonzero, ignore any command list
   elements which are actually help classes rather than commands (i.e.
   the function field of the struct cmd_list_element is 0).  */

struct cmd_list_element *
lookup_cmd_1 (text, clist, result_list, ignore_help_classes)
     char **text;
     struct cmd_list_element *clist, **result_list;
     int ignore_help_classes;
{
  char *p, *command;
  int len, tmp, nfound;
  struct cmd_list_element *found, *c;

  while (**text == ' ' || **text == '\t')
    (*text)++;

  /* Treating underscores as part of command words is important
     so that "set args_foo()" doesn't get interpreted as
     "set args _foo()".  */
  for (p = *text;
       *p && (isalnum(*p) || *p == '-' || *p == '_');
       p++)
    ;

  /* If nothing but whitespace, return 0.  */
  if (p == *text)
    return 0;
  
  len = p - *text;

  /* *text and p now bracket the first command word to lookup (and
     it's length is len).  We copy this into a local temporary,
     converting to lower case as we go.  */

  command = (char *) alloca (len + 1);
  for (tmp = 0; tmp < len; tmp++)
    {
      char x = (*text)[tmp];
      command[tmp] = (x >= 'A' && x <= 'Z') ? x - 'A' + 'a' : x;
    }
  command[len] = '\0';

  /* Look it up.  */
  found = 0;
  nfound = 0;
  for (c = clist; c; c = c->next)
    if (!strncmp (command, c->name, len)
	&& (!ignore_help_classes || c->function))
      {
	found = c;
	nfound++;
	if (c->name[len] == '\0')
	  {
	    nfound = 1;
	    break;
	  }
      }

  /* If nothing matches, we have a simple failure.  */
  if (nfound == 0)
    return 0;

  if (nfound > 1)
    {
      if (result_list != NULL)
	/* Will be modified in calling routine
	   if we know what the prefix command is.  */
	*result_list = 0;		
      return (struct cmd_list_element *) -1; /* Ambiguous.  */
    }

  /* We've matched something on this list.  Move text pointer forward. */

  *text = p;
  if (found->prefixlist)
    {
      c = lookup_cmd_1 (text, *found->prefixlist, result_list,
			ignore_help_classes);
      if (!c)
	{
	  /* Didn't find anything; this is as far as we got.  */
	  if (result_list != NULL)
	    *result_list = clist;
	  return found;
	}
      else if (c == (struct cmd_list_element *) -1)
	{
	  /* We've gotten this far properley, but the next step
	     is ambiguous.  We need to set the result list to the best
	     we've found (if an inferior hasn't already set it).  */
	  if (result_list != NULL)
	    if (!*result_list)
	      /* This used to say *result_list = *found->prefixlist
		 If that was correct, need to modify the documentation
		 at the top of this function to clarify what is supposed
		 to be going on.  */
	      *result_list = found;
	  return c;
	}
      else
	{
	  /* We matched!  */
	  return c;
	}
    }
  else
    {
      if (result_list != NULL)
	*result_list = clist;
      return found;
    }
}

/* Look up the contents of *LINE as a command in the command list LIST.
   LIST is a chain of struct cmd_list_element's.
   If it is found, return the struct cmd_list_element for that command
   and update *LINE to point after the command name, at the first argument.
   If not found, call error if ALLOW_UNKNOWN is zero
   otherwise (or if error returns) return zero.
   Call error if specified command is ambiguous,
   unless ALLOW_UNKNOWN is negative.
   CMDTYPE precedes the word "command" in the error message.

   If INGNORE_HELP_CLASSES is nonzero, ignore any command list
   elements which are actually help classes rather than commands (i.e.
   the function field of the struct cmd_list_element is 0).  */

struct cmd_list_element *
lookup_cmd (line, list, cmdtype, allow_unknown, ignore_help_classes)
     char **line;
     struct cmd_list_element *list;
     char *cmdtype;
     int allow_unknown;
     int ignore_help_classes;
{
  struct cmd_list_element *last_list = 0;
  struct cmd_list_element *c =
    lookup_cmd_1 (line, list, &last_list, ignore_help_classes);
  char *ptr = (*line) + strlen (*line) - 1;

  /* Clear off trailing whitespace.  */
  while (ptr >= *line && (*ptr == ' ' || *ptr == '\t'))
    ptr--;
  *(ptr + 1) = '\0';
  
  if (!c)
    {
      if (!allow_unknown)
	{
	  if (!*line)
	    error ("Lack of needed %scommand", cmdtype);
	  else
	    {
	      char *p = *line, *q;

	      while (isalnum(*p) || *p == '-')
		p++;

	      q = (char *) alloca (p - *line + 1);
	      strncpy (q, *line, p - *line);
	      q[p-*line] = '\0';
	      
	      error ("Undefined %scommand: \"%s\".", cmdtype, q);
	    }
	}
      else
	return 0;
    }
  else if (c == (struct cmd_list_element *) -1)
    {
      /* Ambigous.  Local values should be off prefixlist or called
	 values.  */
      int local_allow_unknown = (last_list ? last_list->allow_unknown :
				 allow_unknown);
      char *local_cmdtype = last_list ? last_list->prefixname : cmdtype;
      struct cmd_list_element *local_list =
	(last_list ? *(last_list->prefixlist) : list);
      
      if (local_allow_unknown < 0)
	{
	  if (last_list)
	    return last_list;	/* Found something.  */
	  else
	    return 0;		/* Found nothing.  */
	}
      else
	{
	  /* Report as error.  */
	  int amb_len;
	  char ambbuf[100];

	  for (amb_len = 0;
	       ((*line)[amb_len] && (*line)[amb_len] != ' '
		&& (*line)[amb_len] != '\t');
	       amb_len++)
	    ;
	  
	  ambbuf[0] = 0;
	  for (c = local_list; c; c = c->next)
	    if (!strncmp (*line, c->name, amb_len))
	      {
		if (strlen (ambbuf) + strlen (c->name) + 6 < (int)sizeof ambbuf)
		  {
		    if (strlen (ambbuf))
		      strcat (ambbuf, ", ");
		    strcat (ambbuf, c->name);
		  }
		else
		  {
		    strcat (ambbuf, "..");
		    break;
		  }
	      }
	  error ("Ambiguous %scommand \"%s\": %s.", local_cmdtype,
		 *line, ambbuf);
	  return 0;		/* lint */
	}
    }
  else
    {
      /* We've got something.  It may still not be what the caller
         wants (if this command *needs* a subcommand).  */
      while (**line == ' ' || **line == '\t')
	(*line)++;

      if (c->prefixlist && **line && !c->allow_unknown)
	error ("Undefined %scommand: \"%s\".", c->prefixname, *line);

      /* Seems to be what he wants.  Return it.  */
      return c;
    }
  return 0;
}
	
#if 0
/* Look up the contents of *LINE as a command in the command list LIST.
   LIST is a chain of struct cmd_list_element's.
   If it is found, return the struct cmd_list_element for that command
   and update *LINE to point after the command name, at the first argument.
   If not found, call error if ALLOW_UNKNOWN is zero
   otherwise (or if error returns) return zero.
   Call error if specified command is ambiguous,
   unless ALLOW_UNKNOWN is negative.
   CMDTYPE precedes the word "command" in the error message.  */

struct cmd_list_element *
lookup_cmd (line, list, cmdtype, allow_unknown)
     char **line;
     struct cmd_list_element *list;
     char *cmdtype;
     int allow_unknown;
{
  register char *p;
  register struct cmd_list_element *c, *found;
  int nfound;
  char ambbuf[100];
  char *processed_cmd;
  int i, cmd_len;

  /* Skip leading whitespace.  */

  while (**line == ' ' || **line == '\t')
    (*line)++;

  /* Clear out trailing whitespace.  */

  p = *line + strlen (*line);
  while (p != *line && (p[-1] == ' ' || p[-1] == '\t'))
    p--;
  *p = 0;

  /* Find end of command name.  */

  p = *line;
  while (*p == '-'
	 || (*p >= 'a' && *p <= 'z')
	 || (*p >= 'A' && *p <= 'Z')
	 || (*p >= '0' && *p <= '9'))
    p++;

  /* Look up the command name.
     If exact match, keep that.
     Otherwise, take command abbreviated, if unique.  Note that (in my
     opinion) a null string does *not* indicate ambiguity; simply the
     end of the argument.  */

  if (p == *line)
    {
      if (!allow_unknown)
	error ("Lack of needed %scommand", cmdtype);
      return 0;
    }
  
  /* Copy over to a local buffer, converting to lowercase on the way.
     This is in case the command being parsed is a subcommand which
     doesn't match anything, and that's ok.  We want the original
     untouched for the routine of the original command.  */
  
  processed_cmd = (char *) alloca (p - *line + 1);
  for (cmd_len = 0; cmd_len < p - *line; cmd_len++)
    {
      char x = (*line)[cmd_len];
      if (x >= 'A' && x <= 'Z')
	processed_cmd[cmd_len] = x - 'A' + 'a';
      else
	processed_cmd[cmd_len] = x;
    }
  processed_cmd[cmd_len] = '\0';

  /* Check all possibilities in the current command list.  */
  found = 0;
  nfound = 0;
  for (c = list; c; c = c->next)
    {
      if (!strncmp (processed_cmd, c->name, cmd_len))
	{
	  found = c;
	  nfound++;
	  if (c->name[cmd_len] == 0)
	    {
	      nfound = 1;
	      break;
	    }
	}
    }

  /* Report error for undefined command name.  */

  if (nfound != 1)
    {
      if (nfound > 1 && allow_unknown >= 0)
	{
	  ambbuf[0] = 0;
	  for (c = list; c; c = c->next)
	    if (!strncmp (processed_cmd, c->name, cmd_len))
	      {
		if (strlen (ambbuf) + strlen (c->name) + 6 < sizeof ambbuf)
		  {
		    if (strlen (ambbuf))
		      strcat (ambbuf, ", ");
		    strcat (ambbuf, c->name);
		  }
		else
		  {
		    strcat (ambbuf, "..");
		    break;
		  }
	      }
	  error ("Ambiguous %scommand \"%s\": %s.", cmdtype,
		 processed_cmd, ambbuf);
	}
      else if (!allow_unknown)
	error ("Undefined %scommand: \"%s\".", cmdtype, processed_cmd);
      return 0;
    }

  /* Skip whitespace before the argument.  */

  while (*p == ' ' || *p == '\t') p++;
  *line = p;

  if (found->prefixlist && *p)
    {
      c = lookup_cmd (line, *found->prefixlist, found->prefixname,
		      found->allow_unknown);
      if (c)
	return c;
    }

  return found;
}
#endif

/* Helper function for SYMBOL_COMPLETION_FUNCTION.  */

/* Return a vector of char pointers which point to the different
   possible completions in LIST of TEXT.  */

char **
complete_on_cmdlist (list, text)
     struct cmd_list_element *list;
     char *text;
{
  struct cmd_list_element *ptr;
  char **matchlist;
  int sizeof_matchlist;
  int matches;
  int textlen = strlen (text);

  sizeof_matchlist = 10;
  matchlist = (char **) xmalloc (sizeof_matchlist * sizeof (char *));
  matches = 0;

  for (ptr = list; ptr; ptr = ptr->next)
    if (!strncmp (ptr->name, text, textlen)
	&& !ptr->abbrev_flag
	&& (ptr->function
	    || ptr->prefixlist))
      {
	if (matches == sizeof_matchlist)
	  {
	    sizeof_matchlist *= 2;
	    matchlist = (char **) xrealloc ((char *)matchlist,
					    (sizeof_matchlist
					     * sizeof (char *)));
	  }

	matchlist[matches] = (char *) 
	  xmalloc (strlen (ptr->name) + 1);
	strcpy (matchlist[matches++], ptr->name);
      }

  if (matches == 0)
    {
      free (matchlist);
      matchlist = 0;
    }
  else
    {
      matchlist = (char **) xrealloc ((char *)matchlist, ((matches + 1)
						* sizeof (char *)));
      matchlist[matches] = (char *) 0;
    }

  return matchlist;
}

static int
parse_binary_operation (arg)
     char *arg;
{
  int length;

  if (!arg || !*arg)
    return 1;

  length = strlen (arg);

  while (arg[length - 1] == ' ' || arg[length - 1] == '\t')
    length--;

  if (!strncmp (arg, "on", length)
      || !strncmp (arg, "1", length)
      || !strncmp (arg, "yes", length))
    return 1;
  else
    if (!strncmp (arg, "off", length)
	|| !strncmp (arg, "0", length)
	|| !strncmp (arg, "no", length))
      return 0;
    else 
      {
	error ("\"on\" or \"off\" expected.");
	return 0;
      }
}

/* Do a "set" or "show" command.  ARG is NULL if no argument, or the text
   of the argument, and FROM_TTY is nonzero if this command is being entered
   directly by the user (i.e. these are just like any other
   command).  C is the command list element for the command.  */
void
do_setshow_command (arg, from_tty, c)
     char *arg;
     int from_tty;
     struct cmd_list_element *c;
{
  if (c->type == set_cmd)
    {
      switch (c->var_type)
	{
	case var_string:
	  {
	    char *new;
	    char *p;
	    char *q;
	    int ch;
	    
	    if (arg == NULL)
	      arg = "";
	    new = (char *) xmalloc (strlen (arg) + 2);
	    p = arg; q = new;
	    while (ch = *p++)
	      {
		if (ch == '\\')
		  {
		    /* \ at end of argument is used after spaces
		       so they won't be lost.  */
		    if (*p == 0)
		      break;
		    ch = parse_escape (&p);
		    if (ch == 0)
		      break; /* C loses */
		    else if (ch > 0)
		      *q++ = ch;
		  }
		else
		  *q++ = ch;
	      }
	    if (*(p - 1) != '\\')
	      *q++ = ' ';
	    *q++ = '\0';
	    new = (char *) xrealloc (new, q - new);
	    if (*(char **)c->var != NULL)
	      free (*(char **)c->var);
	    *(char **) c->var = new;
	  }
	  break;
	case var_string_noescape:
	  if (arg == NULL)
	    arg = "";
	  if (*(char **)c->var != NULL)
	    free (*(char **)c->var);
	  *(char **) c->var = savestring (arg, strlen (arg));
	  break;
	case var_filename:
	  if (arg == NULL)
	    error_no_arg ("filename to set it to.");
	  if (*(char **)c->var != NULL)
	    free (*(char **)c->var);
	  *(char **)c->var = tilde_expand (arg);
	  break;
	case var_boolean:
	  *(int *) c->var = parse_binary_operation (arg);
	  break;
	case var_uinteger:
	  if (arg == NULL)
	    error_no_arg ("integer to set it to.");
	  *(int *) c->var = parse_and_eval_address (arg);
	  if (*(int *) c->var == 0)
	    *(int *) c->var = UINT_MAX;
	  break;
	case var_zinteger:
	  if (arg == NULL)
	    error_no_arg ("integer to set it to.");
	  *(int *) c->var = parse_and_eval_address (arg);
	  break;
	default:
	  error ("gdb internal error: bad var_type in do_setshow_command");
	}
    }
  else if (c->type == show_cmd)
    {
      /* Print doc minus "show" at start.  */
      print_doc_line (stdout, c->doc + 5);
      
      fputs_filtered (" is ", stdout);
      wrap_here ("    ");
      switch (c->var_type)
	{
      case var_string:
	{
	  unsigned char *p;
	  fputs_filtered ("\"", stdout);
	  for (p = *(unsigned char **) c->var; *p != '\0'; p++)
	    printchar (*p, stdout, '"');
	  fputs_filtered ("\"", stdout);
	}
	break;
      case var_string_noescape:
      case var_filename:
	fputs_filtered ("\"", stdout);
	fputs_filtered (*(char **) c->var, stdout);
	fputs_filtered ("\"", stdout);
	break;
      case var_boolean:
	fputs_filtered (*(int *) c->var ? "on" : "off", stdout);
	break;
      case var_uinteger:
	if (*(unsigned int *) c->var == UINT_MAX) {
	  fputs_filtered ("unlimited", stdout);
	  break;
	}
	/* else fall through */
      case var_zinteger:
	fprintf_filtered (stdout, "%d", *(unsigned int *) c->var);
	break;
      default:
	error ("gdb internal error: bad var_type in do_setshow_command");
      }
      fputs_filtered (".\n", stdout);
    }
  else
    error ("gdb internal error: bad cmd_type in do_setshow_command");
  (*c->function) (NULL, from_tty, c);
}

/* Show all the settings in a list of show commands.  */

void
cmd_show_list (list, from_tty, prefix)
     struct cmd_list_element *list;
     int from_tty;
     char *prefix;
{
  for (; list != NULL; list = list->next) {
    /* If we find a prefix, run its list, prefixing our output by its
       prefix (with "show " skipped).  */
    if (list->prefixlist && !list->abbrev_flag)
      cmd_show_list (*list->prefixlist, from_tty, list->prefixname + 5);
    if (list->type == show_cmd)
      {
	fputs_filtered (prefix, stdout);
	fputs_filtered (list->name, stdout);
	fputs_filtered (":  ", stdout);
	do_setshow_command ((char *)NULL, from_tty, list);
      }
  }
}

/* ARGSUSED */
static void
shell_escape (arg, from_tty)
     char *arg;
     int from_tty;
{
  int rc, status, pid;
  char *p, *user_shell;
  extern char *rindex ();

  if ((user_shell = (char *) getenv ("SHELL")) == NULL)
    user_shell = "/bin/sh";

  /* Get the name of the shell for arg0 */
  if ((p = rindex (user_shell, '/')) == NULL)
    p = user_shell;
  else
    p++;			/* Get past '/' */

  if ((pid = fork()) == 0)
    {
      if (!arg)
	execl (user_shell, p, 0);
      else
	execl (user_shell, p, "-c", arg, 0);

      fprintf (stderr, "Exec of shell failed\n");
      exit (0);
    }

  if (pid != -1)
    while ((rc = wait (&status)) != pid && rc != -1)
      ;
  else
    error ("Fork failed");
}

static void
make_command (arg, from_tty)
     char *arg;
     int from_tty;
{
  char *p;

  if (arg == 0)
    p = "make";
  else
    {
      p = xmalloc (sizeof("make ") + strlen(arg));
      strcpy (p, "make ");
      strcpy (p + sizeof("make ")-1, arg);
    }
  
  shell_escape (p, from_tty);
}

static void
user_info_1 (c, stream)
     struct cmd_list_element *c;
     FILE *stream;
{
  register struct command_line *cmdlines;

  cmdlines = c->user_commands;
  if (!cmdlines)
    return;
  fprintf_filtered (stream, "User command %s:\n", c->name);
  while (cmdlines)
    {
      fprintf_filtered (stream, "%s\n", cmdlines->line); 
      cmdlines = cmdlines->next;
    }
  fputs_filtered ("\n", stream);
}

/* ARGSUSED */
static void
user_info (args, from_tty)
     char *args;
     int from_tty;
{
  struct cmd_list_element *c;
  extern struct cmd_list_element *cmdlist;

  if (args)
    {
      c = lookup_cmd (&args, cmdlist, "", 0, 1);
      if (c->class != class_user)
	error ("Not a user command.");
      user_info_1 (c, stdout);
    }
  else
    {
      for (c = cmdlist; c; c = c->next)
	{
	  if (c->class == class_user)
	    user_info_1 (c, stdout);
	}
    }
}

void
_initialize_command ()
{
  add_com ("shell", class_support, shell_escape,
	   "Execute the rest of the line as a shell command.  \n\
With no arguments, run an inferior shell.");

  add_com ("make", class_support, make_command,
	   "Run the ``make'' program using the rest of the line as arguments.");

  add_info ("user", user_info, "Show definitions of user defined commands.\n\
Argument is the name of the user defined command.\n\
With no argument, show definitions of all user defined commands.");
}