summaryrefslogtreecommitdiff
path: root/Build/source/utils/texinfo/info/tilde.c
blob: 602963115b888911e652f061eb09e8a0fbec7faa (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
/* tilde.c -- tilde expansion code (~/foo := $HOME/foo).
   $Id: tilde.c,v 1.7 2007/07/01 21:20:31 karl Exp $

   Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1996, 1998, 1999,
   2002, 2004, 2006, 2007 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 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/>.

   Written by Brian Fox (bfox@ai.mit.edu). */

#include "info.h"
#include "tilde.h"

#if defined (TEST) || defined (STATIC_MALLOC)
static void *xmalloc (), *xrealloc ();
#endif /* TEST || STATIC_MALLOC */

/* The default value of tilde_additional_prefixes.  This is set to
   whitespace preceding a tilde so that simple programs which do not
   perform any word separation get desired behaviour. */
static char *default_prefixes[] =
  { " ~", "\t~", (char *)NULL };

/* The default value of tilde_additional_suffixes.  This is set to
   whitespace or newline so that simple programs which do not
   perform any word separation get desired behaviour. */
static char *default_suffixes[] =
  { " ", "\n", (char *)NULL };

/* If non-null, this contains the address of a function to call if the
   standard meaning for expanding a tilde fails.  The function is called
   with the text (sans tilde, as in "foo"), and returns a malloc()'ed string
   which is the expansion, or a NULL pointer if there is no expansion. */
CFunction *tilde_expansion_failure_hook = (CFunction *)NULL;

/* When non-null, this is a NULL terminated array of strings which
   are duplicates for a tilde prefix.  Bash uses this to expand
   `=~' and `:~'. */
char **tilde_additional_prefixes = default_prefixes;

/* When non-null, this is a NULL terminated array of strings which match
   the end of a username, instead of just "/".  Bash sets this to
   `:' and `=~'. */
char **tilde_additional_suffixes = default_suffixes;

/* Find the start of a tilde expansion in STRING, and return the index of
   the tilde which starts the expansion.  Place the length of the text
   which identified this tilde starter in LEN, excluding the tilde itself. */
static int
tilde_find_prefix (char *string, int *len)
{
  register int i, j, string_len;
  register char **prefixes = tilde_additional_prefixes;

  string_len = strlen (string);
  *len = 0;

  if (!*string || *string == '~')
    return (0);

  if (prefixes)
    {
      for (i = 0; i < string_len; i++)
        {
          for (j = 0; prefixes[j]; j++)
            {
              if (strncmp (string + i, prefixes[j], strlen (prefixes[j])) == 0)
                {
                  *len = strlen (prefixes[j]) - 1;
                  return (i + *len);
                }
            }
        }
    }
  return (string_len);
}

/* Find the end of a tilde expansion in STRING, and return the index of
   the character which ends the tilde definition.  */
static int
tilde_find_suffix (char *string)
{
  register int i, j, string_len;
  register char **suffixes = tilde_additional_suffixes;

  string_len = strlen (string);

  for (i = 0; i < string_len; i++)
    {
      if (IS_SLASH (string[i]) || !string[i])
        break;

      for (j = 0; suffixes && suffixes[j]; j++)
        {
          if (strncmp (string + i, suffixes[j], strlen (suffixes[j])) == 0)
            return (i);
        }
    }
  return (i);
}

/* Return a new string which is the result of tilde expanding STRING. */
char *
tilde_expand (char *string)
{
  char *result;
  int result_size, result_index;

  result_size = result_index = 0;
  result = (char *)NULL;

  /* Scan through STRING expanding tildes as we come to them. */
  while (1)
    {
      register int start, end;
      char *tilde_word, *expansion;
      int len;

      /* Make START point to the tilde which starts the expansion. */
      start = tilde_find_prefix (string, &len);

      /* Copy the skipped text into the result. */
      if ((result_index + start + 1) > result_size)
        result = (char *)xrealloc (result, 1 + (result_size += (start + 20)));

      strncpy (result + result_index, string, start);
      result_index += start;

      /* Advance STRING to the starting tilde. */
      string += start;

      /* Make END be the index of one after the last character of the
         username. */
      end = tilde_find_suffix (string);

      /* If both START and END are zero, we are all done. */
      if (!start && !end)
        break;

      /* Expand the entire tilde word, and copy it into RESULT. */
      tilde_word = (char *)xmalloc (1 + end);
      strncpy (tilde_word, string, end);
      tilde_word[end] = '\0';
      string += end;

      expansion = tilde_expand_word (tilde_word);
      free (tilde_word);

      len = strlen (expansion);
      if ((result_index + len + 1) > result_size)
        result = (char *)xrealloc (result, 1 + (result_size += (len + 20)));

      strcpy (result + result_index, expansion);
      result_index += len;
      free (expansion);
    }

  result[result_index] = '\0';

  return (result);
}

/* Do the work of tilde expansion on FILENAME.  FILENAME starts with a
   tilde.  If there is no expansion, call tilde_expansion_failure_hook. */
char *
tilde_expand_word (char *filename)
{
  char *dirname = filename ? xstrdup (filename) : NULL;

  if (dirname && *dirname == '~')
    {
      char *temp_name;
      if (!dirname[1] || IS_SLASH (dirname[1]))
        {
          /* Prepend $HOME to the rest of the string. */
          char *temp_home = getenv ("HOME");

          /* If there is no HOME variable, look up the directory in
             the password database. */
          if (!temp_home)
            {
              struct passwd *entry;

              entry = (struct passwd *) getpwuid (getuid ());
              if (entry)
                temp_home = entry->pw_dir;
            }

          temp_name = xmalloc (1 + strlen (&dirname[1])
                               + (temp_home ? strlen (temp_home) : 0));
          if (temp_home)
            strcpy (temp_name, temp_home);
          else
            temp_name[0] = 0;
          strcat (temp_name, &dirname[1]);
          free (dirname);
          dirname = xstrdup (temp_name);
          free (temp_name);
        }
      else
        {
          struct passwd *user_entry;
          char *username = xmalloc (257);
          int i, c;

          for (i = 1; (c = dirname[i]); i++)
            {
              if (IS_SLASH (c))
                break;
              else
                username[i - 1] = c;
            }
          username[i - 1] = 0;

          if (!(user_entry = (struct passwd *) getpwnam (username)))
            {
              /* If the calling program has a special syntax for
                 expanding tildes, and we couldn't find a standard
                 expansion, then let them try. */
              if (tilde_expansion_failure_hook)
                {
                  char *expansion = (*tilde_expansion_failure_hook) (username);

                  if (expansion)
                    {
                      temp_name = xmalloc (1 + strlen (expansion)
                                           + strlen (&dirname[i])); 
                      strcpy (temp_name, expansion);
                      strcat (temp_name, &dirname[i]);
                      free (expansion);
                      goto return_name;
                    }
                }
              /* We shouldn't report errors. */
            }
          else
            {
              temp_name = xmalloc (1 + strlen (user_entry->pw_dir)
                                   + strlen (&dirname[i])); 
              strcpy (temp_name, user_entry->pw_dir);
              strcat (temp_name, &dirname[i]);

            return_name:
              free (dirname);
              dirname = xstrdup (temp_name);
              free (temp_name);
            }

          endpwent ();
          free (username);
        }
    }
  return dirname;
}


#if defined (TEST)
#undef NULL
#include <stdio.h>

main (argc, argv)
     int argc;
     char **argv;
{
  char *result, line[512];
  int done = 0;

  while (!done)
    {
      printf ("~expand: ");
      fflush (stdout);

      if (!gets (line))
        strcpy (line, "done");

      if ((strcmp (line, "done") == 0) ||
          (strcmp (line, "quit") == 0) ||
          (strcmp (line, "exit") == 0))
        {
          done = 1;
          break;
        }

      result = tilde_expand (line);
      printf ("  --> %s\n", result);
      free (result);
    }
  xexit (0);
}

static void memory_error_and_abort ();

static void *
xmalloc (bytes)
     int bytes;
{
  void *temp = (void *)malloc (bytes);

  if (!temp)
    memory_error_and_abort ();
  return (temp);
}

static void *
xrealloc (pointer, bytes)
     void *pointer;
     int bytes;
{
  void *temp;

  if (!pointer)
    temp = (char *)malloc (bytes);
  else
    temp = (char *)realloc (pointer, bytes);

  if (!temp)
    memory_error_and_abort ();

  return (temp);
}

static void
memory_error_and_abort ()
{
  fprintf (stderr, _("readline: Out of virtual memory!\n"));
  abort ();
}
#endif /* TEST */