about summary refs log tree commit diff
path: root/iconv/gconv_conf.c
blob: 682f9498343ccc96ec5ceef8842cd74d2dec34f2 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
/* Handle configuration data.
   Copyright (C) 1997-2021 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <locale.h>
#include <search.h>
#include <stddef.h>
#include <stdio.h>
#include <stdio_ext.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/param.h>

#include <libc-lock.h>
#include <gconv_int.h>


/* This is the default path where we look for module lists.  */
static const char default_gconv_path[] = GCONV_PATH;

/* Type to represent search path.  */
struct path_elem
{
  const char *name;
  size_t len;
};

/* The path elements, as determined by the __gconv_get_path function.
   All path elements end in a slash.  */
struct path_elem *__gconv_path_elem;
/* Maximum length of a single path element in __gconv_path_elem.  */
size_t __gconv_max_path_elem_len;

/* We use the following struct if we couldn't allocate memory.  */
static const struct path_elem empty_path_elem = { NULL, 0 };

/* Name of the file containing the module information in the directories
   along the path.  */
static const char gconv_conf_filename[] = "gconv-modules";

/* Filename extension for the modules.  */
#ifndef MODULE_EXT
# define MODULE_EXT ".so"
#endif
static const char gconv_module_ext[] = MODULE_EXT;

/* We have a few builtin transformations.  */
static struct gconv_module builtin_modules[] =
{
#define BUILTIN_TRANSFORMATION(From, To, Cost, Name, Fct, BtowcFct, \
			       MinF, MaxF, MinT, MaxT) \
  {									      \
    .from_string = From,						      \
    .to_string = To,							      \
    .cost_hi = Cost,							      \
    .cost_lo = INT_MAX,							      \
    .module_name = Name							      \
  },
#define BUILTIN_ALIAS(From, To)

#include "gconv_builtin.h"

#undef BUILTIN_TRANSFORMATION
#undef BUILTIN_ALIAS
};

static const char builtin_aliases[] =
{
#define BUILTIN_TRANSFORMATION(From, To, Cost, Name, Fct, BtowcFct, \
			       MinF, MaxF, MinT, MaxT)
#define BUILTIN_ALIAS(From, To) From "\0" To "\0"

#include "gconv_builtin.h"

#undef BUILTIN_TRANSFORMATION
#undef BUILTIN_ALIAS
};

#include <libio/libioP.h>
#define __getdelim(line, len, c, fp) _IO_getdelim (line, len, c, fp)


/* Value of the GCONV_PATH environment variable.  */
const char *__gconv_path_envvar;


/* Test whether there is already a matching module known.  */
static int
detect_conflict (const char *alias)
{
  struct gconv_module *node = __gconv_modules_db;

  while (node != NULL)
    {
      int cmpres = strcmp (alias, node->from_string);

      if (cmpres == 0)
	/* We have a conflict.  */
	return 1;
      else if (cmpres < 0)
	node = node->left;
      else
	node = node->right;
    }

  return node != NULL;
}


/* The actual code to add aliases.  */
static void
add_alias2 (const char *from, const char *to, const char *wp, void *modules)
{
  /* Test whether this alias conflicts with any available module.  */
  if (detect_conflict (from))
    /* It does conflict, don't add the alias.  */
    return;

  struct gconv_alias *new_alias = (struct gconv_alias *)
    malloc (sizeof (struct gconv_alias) + (wp - from));
  if (new_alias != NULL)
    {
      void **inserted;

      new_alias->fromname = memcpy ((char *) new_alias
				    + sizeof (struct gconv_alias),
				    from, wp - from);
      new_alias->toname = new_alias->fromname + (to - from);

      inserted = (void **) __tsearch (new_alias, &__gconv_alias_db,
				      __gconv_alias_compare);
      if (inserted == NULL || *inserted != new_alias)
	/* Something went wrong, free this entry.  */
	free (new_alias);
    }
}


/* Add new alias.  */
static void
add_alias (char *rp, void *modules)
{
  /* We now expect two more string.  The strings are normalized
     (converted to UPPER case) and strored in the alias database.  */
  char *from, *to, *wp;

  while (__isspace_l (*rp, _nl_C_locobj_ptr))
    ++rp;
  from = wp = rp;
  while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
    *wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);
  if (*rp == '\0')
    /* There is no `to' string on the line.  Ignore it.  */
    return;
  *wp++ = '\0';
  to = ++rp;
  while (__isspace_l (*rp, _nl_C_locobj_ptr))
    ++rp;
  while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
    *wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);
  if (to == wp)
    /* No `to' string, ignore the line.  */
    return;
  *wp++ = '\0';

  add_alias2 (from, to, wp, modules);
}


/* Insert a data structure for a new module in the search tree.  */
static void
insert_module (struct gconv_module *newp, int tobefreed)
{
  struct gconv_module **rootp = &__gconv_modules_db;

  while (*rootp != NULL)
    {
      struct gconv_module *root = *rootp;
      int cmpres;

      cmpres = strcmp (newp->from_string, root->from_string);
      if (cmpres == 0)
	{
	  /* Both strings are identical.  Insert the string at the
	     end of the `same' list if it is not already there.  */
	  while (strcmp (newp->from_string, root->from_string) != 0
		 || strcmp (newp->to_string, root->to_string) != 0)
	    {
	      rootp = &root->same;
	      root = *rootp;
	      if (root == NULL)
		break;
	    }

	  if (root != NULL)
	    {
	      /* This is a no new conversion.  But maybe the cost is
		 better.  */
	      if (newp->cost_hi < root->cost_hi
		  || (newp->cost_hi == root->cost_hi
		      && newp->cost_lo < root->cost_lo))
		{
		  newp->left = root->left;
		  newp->right = root->right;
		  newp->same = root->same;
		  *rootp = newp;

		  free (root);
		}
	      else if (tobefreed)
		free (newp);
	      return;
	    }

	  break;
	}
      else if (cmpres < 0)
	rootp = &root->left;
      else
	rootp = &root->right;
    }

  /* Plug in the new node here.  */
  *rootp = newp;
}


/* Add new module.  */
static void
add_module (char *rp, const char *directory, size_t dir_len, void **modules,
	    size_t *nmodules, int modcounter)
{
  /* We expect now
     1. `from' name
     2. `to' name
     3. filename of the module
     4. an optional cost value
  */
  struct gconv_alias fake_alias;
  struct gconv_module *new_module;
  char *from, *to, *module, *wp;
  int need_ext;
  int cost_hi;

  while (__isspace_l (*rp, _nl_C_locobj_ptr))
    ++rp;
  from = rp;
  while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
    {
      *rp = __toupper_l (*rp, _nl_C_locobj_ptr);
      ++rp;
    }
  if (*rp == '\0')
    return;
  *rp++ = '\0';
  to = wp = rp;
  while (__isspace_l (*rp, _nl_C_locobj_ptr))
    ++rp;
  while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
    *wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);
  if (*rp == '\0')
    return;
  *wp++ = '\0';
  do
    ++rp;
  while (__isspace_l (*rp, _nl_C_locobj_ptr));
  module = wp;
  while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
    *wp++ = *rp++;
  if (*rp == '\0')
    {
      /* There is no cost, use one by default.  */
      *wp++ = '\0';
      cost_hi = 1;
    }
  else
    {
      /* There might be a cost value.  */
      char *endp;

      *wp++ = '\0';
      cost_hi = strtol (rp, &endp, 10);
      if (rp == endp || cost_hi < 1)
	/* No useful information.  */
	cost_hi = 1;
    }

  if (module[0] == '\0')
    /* No module name given.  */
    return;
  if (module[0] == '/')
    dir_len = 0;

  /* See whether we must add the ending.  */
  need_ext = 0;
  if (wp - module < (ptrdiff_t) sizeof (gconv_module_ext)
      || memcmp (wp - sizeof (gconv_module_ext), gconv_module_ext,
		 sizeof (gconv_module_ext)) != 0)
    /* We must add the module extension.  */
    need_ext = sizeof (gconv_module_ext) - 1;

  /* See whether we have already an alias with this name defined.  */
  fake_alias.fromname = strndupa (from, to - from);

  if (__tfind (&fake_alias, &__gconv_alias_db, __gconv_alias_compare) != NULL)
    /* This module duplicates an alias.  */
    return;

  new_module = (struct gconv_module *) calloc (1,
					       sizeof (struct gconv_module)
					       + (wp - from)
					       + dir_len + need_ext);
  if (new_module != NULL)
    {
      char *tmp;

      new_module->from_string = tmp = (char *) (new_module + 1);
      tmp = __mempcpy (tmp, from, to - from);

      new_module->to_string = tmp;
      tmp = __mempcpy (tmp, to, module - to);

      new_module->cost_hi = cost_hi;
      new_module->cost_lo = modcounter;

      new_module->module_name = tmp;

      if (dir_len != 0)
	tmp = __mempcpy (tmp, directory, dir_len);

      tmp = __mempcpy (tmp, module, wp - module);

      if (need_ext)
	memcpy (tmp - 1, gconv_module_ext, sizeof (gconv_module_ext));

      /* Now insert the new module data structure in our search tree.  */
      insert_module (new_module, 1);
    }
}


/* Read the next configuration file.  */
static void
read_conf_file (const char *filename, const char *directory, size_t dir_len,
		void **modules, size_t *nmodules)
{
  /* Note the file is opened with cancellation in the I/O functions
     disabled.  */
  FILE *fp = fopen (filename, "rce");
  char *line = NULL;
  size_t line_len = 0;
  static int modcounter;

  /* Don't complain if a file is not present or readable, simply silently
     ignore it.  */
  if (fp == NULL)
    return;

  /* No threads reading from this stream.  */
  __fsetlocking (fp, FSETLOCKING_BYCALLER);

  /* Process the known entries of the file.  Comments start with `#' and
     end with the end of the line.  Empty lines are ignored.  */
  while (!__feof_unlocked (fp))
    {
      char *rp, *endp, *word;
      ssize_t n = __getdelim (&line, &line_len, '\n', fp);
      if (n < 0)
	/* An error occurred.  */
	break;

      rp = line;
      /* Terminate the line (excluding comments or newline) by an NUL byte
	 to simplify the following code.  */
      endp = strchr (rp, '#');
      if (endp != NULL)
	*endp = '\0';
      else
	if (rp[n - 1] == '\n')
	  rp[n - 1] = '\0';

      while (__isspace_l (*rp, _nl_C_locobj_ptr))
	++rp;

      /* If this is an empty line go on with the next one.  */
      if (rp == endp)
	continue;

      word = rp;
      while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
	++rp;

      if (rp - word == sizeof ("alias") - 1
	  && memcmp (word, "alias", sizeof ("alias") - 1) == 0)
	add_alias (rp, *modules);
      else if (rp - word == sizeof ("module") - 1
	       && memcmp (word, "module", sizeof ("module") - 1) == 0)
	add_module (rp, directory, dir_len, modules, nmodules, modcounter++);
      /* else */
	/* Otherwise ignore the line.  */
    }

  free (line);

  fclose (fp);
}


/* Determine the directories we are looking for data in.  This function should
   only be called from __gconv_read_conf.  */
static void
__gconv_get_path (void)
{
  struct path_elem *result;

  /* This function is only ever called when __gconv_path_elem is NULL.  */
  result = __gconv_path_elem;
  assert (result == NULL);

  /* Determine the complete path first.  */
  char *gconv_path;
  size_t gconv_path_len;
  char *elem;
  char *oldp;
  char *cp;
  int nelems;
  char *cwd;
  size_t cwdlen;

  if (__gconv_path_envvar == NULL)
    {
      /* No user-defined path.  Make a modifiable copy of the
         default path.  */
      gconv_path = strdupa (default_gconv_path);
      gconv_path_len = sizeof (default_gconv_path);
      cwd = NULL;
      cwdlen = 0;
    }
  else
    {
      /* Append the default path to the user-defined path.  */
      size_t user_len = strlen (__gconv_path_envvar);

      gconv_path_len = user_len + 1 + sizeof (default_gconv_path);
      gconv_path = alloca (gconv_path_len);
      __mempcpy (__mempcpy (__mempcpy (gconv_path, __gconv_path_envvar,
                                       user_len),
                            ":", 1),
                 default_gconv_path, sizeof (default_gconv_path));
      cwd = __getcwd (NULL, 0);
      cwdlen = __glibc_unlikely (cwd == NULL) ? 0 : strlen (cwd);
    }
  assert (default_gconv_path[0] == '/');

  /* In a first pass we calculate the number of elements.  */
  oldp = NULL;
  cp = strchr (gconv_path, ':');
  nelems = 1;
  while (cp != NULL)
    {
      if (cp != oldp + 1)
        ++nelems;
      oldp = cp;
      cp = strchr (cp + 1, ':');
    }

  /* Allocate the memory for the result.  */
  result = malloc ((nelems + 1)
                              * sizeof (struct path_elem)
                              + gconv_path_len + nelems
                              + (nelems - 1) * (cwdlen + 1));
  if (result != NULL)
    {
      char *strspace = (char *) &result[nelems + 1];
      int n = 0;

      /* Separate the individual parts.  */
      __gconv_max_path_elem_len = 0;
      elem = __strtok_r (gconv_path, ":", &gconv_path);
      assert (elem != NULL);
      do
        {
          result[n].name = strspace;
          if (elem[0] != '/')
            {
              assert (cwd != NULL);
              strspace = __mempcpy (strspace, cwd, cwdlen);
              *strspace++ = '/';
            }
          strspace = __stpcpy (strspace, elem);
          if (strspace[-1] != '/')
            *strspace++ = '/';

          result[n].len = strspace - result[n].name;
          if (result[n].len > __gconv_max_path_elem_len)
            __gconv_max_path_elem_len = result[n].len;

          *strspace++ = '\0';
          ++n;
        }
      while ((elem = __strtok_r (NULL, ":", &gconv_path)) != NULL);

      result[n].name = NULL;
      result[n].len = 0;
    }

  __gconv_path_elem = result ?: (struct path_elem *) &empty_path_elem;

  free (cwd);
}


/* Read all configuration files found in the user-specified and the default
   path.  This function should only be called once during the program's
   lifetime.  It disregards locking and synchronization because its only
   caller, __gconv_load_conf, handles this.  */
static void
__gconv_read_conf (void)
{
  void *modules = NULL;
  size_t nmodules = 0;
  int save_errno = errno;
  size_t cnt;

  /* First see whether we should use the cache.  */
  if (__gconv_load_cache () == 0)
    {
      /* Yes, we are done.  */
      __set_errno (save_errno);
      return;
    }

#ifndef STATIC_GCONV
  /* Find out where we have to look.  */
  __gconv_get_path ();

  for (cnt = 0; __gconv_path_elem[cnt].name != NULL; ++cnt)
    {
      const char *elem = __gconv_path_elem[cnt].name;
      size_t elem_len = __gconv_path_elem[cnt].len;
      char *filename;

      /* No slash needs to be inserted between elem and gconv_conf_filename;
	 elem already ends in a slash.  */
      filename = alloca (elem_len + sizeof (gconv_conf_filename));
      __mempcpy (__mempcpy (filename, elem, elem_len),
		 gconv_conf_filename, sizeof (gconv_conf_filename));

      /* Read the next configuration file.  */
      read_conf_file (filename, elem, elem_len, &modules, &nmodules);
    }
#endif

  /* Add the internal modules.  */
  for (cnt = 0; cnt < sizeof (builtin_modules) / sizeof (builtin_modules[0]);
       ++cnt)
    {
      struct gconv_alias fake_alias;

      fake_alias.fromname = (char *) builtin_modules[cnt].from_string;

      if (__tfind (&fake_alias, &__gconv_alias_db, __gconv_alias_compare)
	  != NULL)
	/* It'll conflict so don't add it.  */
	continue;

      insert_module (&builtin_modules[cnt], 0);
    }

  /* Add aliases for builtin conversions.  */
  const char *cp = builtin_aliases;
  do
    {
      const char *from = cp;
      const char *to = __rawmemchr (from, '\0') + 1;
      cp = __rawmemchr (to, '\0') + 1;

      add_alias2 (from, to, cp, modules);
    }
  while (*cp != '\0');

  /* Restore the error number.  */
  __set_errno (save_errno);
}


/* This "once" variable is used to do a one-time load of the configuration.  */
__libc_once_define (static, once);


/* Read all configuration files found in the user-specified and the default
   path, but do it only "once" using __gconv_read_conf to do the actual
   work.  This is the function that must be called when reading iconv
   configuration.  */
void
__gconv_load_conf (void)
{
  __libc_once (once, __gconv_read_conf);
}


/* Free all resources if necessary.  */
libc_freeres_fn (free_mem)
{
  if (__gconv_path_elem != NULL && __gconv_path_elem != &empty_path_elem)
    free ((void *) __gconv_path_elem);
}