about summary refs log tree commit diff
path: root/iconv/gconv_cache.c
blob: 6d19f9f052f874ab369ea043e425ff63024b4840 (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
/* Cache handling for iconv modules.
   Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 2001.

   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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <dlfcn.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>

#include <gconv_int.h>
#include <iconvconfig.h>
#include <not-cancel.h>

#include "../intl/hash-string.h"

static void *gconv_cache;
static size_t cache_size;
static int cache_malloced;


void *
__gconv_get_cache (void)
{
  return gconv_cache;
}


int
internal_function
__gconv_load_cache (void)
{
  int fd;
  struct stat64 st;
  struct gconvcache_header *header;

  /* We cannot use the cache if the GCONV_PATH environment variable is
     set.  */
  __gconv_path_envvar = getenv ("GCONV_PATH");
  if (__gconv_path_envvar != NULL)
    return -1;

  /* See whether the cache file exists.  */
  fd = open_not_cancel (GCONV_MODULES_CACHE, O_RDONLY, 0);
  if (__builtin_expect (fd, 0) == -1)
    /* Not available.  */
    return -1;

  /* Get information about the file.  */
  if (__builtin_expect (__fxstat64 (_STAT_VER, fd, &st), 0) < 0
      /* We do not have to start looking at the file if it cannot contain
	 at least the cache header.  */
      || (size_t) st.st_size < sizeof (struct gconvcache_header))
    {
    close_and_exit:
      close_not_cancel_no_status (fd);
      return -1;
    }

  /* Make the file content available.  */
  cache_size = st.st_size;
#ifdef _POSIX_MAPPED_FILES
  gconv_cache = __mmap (NULL, cache_size, PROT_READ, MAP_SHARED, fd, 0);
  if (__builtin_expect (gconv_cache == MAP_FAILED, 0))
#endif
    {
      size_t already_read;

      gconv_cache = malloc (cache_size);
      if (gconv_cache == NULL)
	goto close_and_exit;

      already_read = 0;
      do
	{
	  ssize_t n = __read (fd, (char *) gconv_cache + already_read,
			      cache_size - already_read);
	  if (__builtin_expect (n, 0) == -1)
	    {
	      free (gconv_cache);
	      gconv_cache = NULL;
	      goto close_and_exit;
	    }

	  already_read += n;
	}
      while (already_read < cache_size);

      cache_malloced = 1;
    }

  /* We don't need the file descriptor anymore.  */
  close_not_cancel_no_status (fd);

  /* Check the consistency.  */
  header = (struct gconvcache_header *) gconv_cache;
  if (__builtin_expect (header->magic, GCONVCACHE_MAGIC) != GCONVCACHE_MAGIC
      || __builtin_expect (header->string_offset >= cache_size, 0)
      || __builtin_expect (header->hash_offset >= cache_size, 0)
      || __builtin_expect (header->hash_size == 0, 0)
      || __builtin_expect ((header->hash_offset
			    + header->hash_size * sizeof (struct hash_entry))
			   > cache_size, 0)
      || __builtin_expect (header->module_offset >= cache_size, 0)
      || __builtin_expect (header->otherconv_offset > cache_size, 0))
    {
      if (cache_malloced)
	{
	  free (gconv_cache);
	  cache_malloced = 0;
	}
#ifdef _POSIX_MAPPED_FILES
      else
	__munmap (gconv_cache, cache_size);
#endif
      gconv_cache = NULL;

      return -1;
    }

  /* That worked.  */
  return 0;
}


static int
internal_function
find_module_idx (const char *str, size_t *idxp)
{
  unsigned int idx;
  unsigned int hval;
  unsigned int hval2;
  const struct gconvcache_header *header;
  const char *strtab;
  const struct hash_entry *hashtab;
  unsigned int limit;

  header = (const struct gconvcache_header *) gconv_cache;
  strtab = (char *) gconv_cache + header->string_offset;
  hashtab = (struct hash_entry *) ((char *) gconv_cache
				   + header->hash_offset);

  hval = hash_string (str);
  idx = hval % header->hash_size;
  hval2 = 1 + hval % (header->hash_size - 2);

  limit = cache_size - header->string_offset;
  while (hashtab[idx].string_offset != 0)
    if (hashtab[idx].string_offset < limit
	&& strcmp (str, strtab + hashtab[idx].string_offset) == 0)
      {
	*idxp = hashtab[idx].module_idx;
	return 0;
      }
    else
      if ((idx += hval2) >= header->hash_size)
	idx -= header->hash_size;

  /* Nothing found.  */
  return -1;
}


#ifndef STATIC_GCONV
static int
internal_function
find_module (const char *directory, const char *filename,
	     struct __gconv_step *result)
{
  size_t dirlen = strlen (directory);
  size_t fnamelen = strlen (filename) + 1;
  char fullname[dirlen + fnamelen];
  int status = __GCONV_NOCONV;

  memcpy (__mempcpy (fullname, directory, dirlen), filename, fnamelen);

  result->__shlib_handle = __gconv_find_shlib (fullname);
  if (result->__shlib_handle != NULL)
    {
      status = __GCONV_OK;

      result->__modname = NULL;
      result->__fct = result->__shlib_handle->fct;
      result->__init_fct = result->__shlib_handle->init_fct;
      result->__end_fct = result->__shlib_handle->end_fct;

      /* These settings can be overridden by the init function.  */
      result->__btowc_fct = NULL;
      result->__data = NULL;

      /* Call the init function.  */
      if (result->__init_fct != NULL)
	status = DL_CALL_FCT (result->__init_fct, (result));
    }

  return status;
}
#endif


int
internal_function
__gconv_compare_alias_cache (const char *name1, const char *name2, int *result)
{
  size_t name1_idx;
  size_t name2_idx;

  if (gconv_cache == NULL)
    return -1;

  if (find_module_idx (name1, &name1_idx) != 0
      || find_module_idx (name2, &name2_idx) != 0)
    *result = strcmp (name1, name2);
  else
    *result = (int) (name1_idx - name2_idx);

  return 0;
}


int
internal_function
__gconv_lookup_cache (const char *toset, const char *fromset,
		      struct __gconv_step **handle, size_t *nsteps, int flags)
{
  const struct gconvcache_header *header;
  const char *strtab;
  size_t fromidx;
  size_t toidx;
  const struct module_entry *modtab;
  const struct module_entry *from_module;
  const struct module_entry *to_module;
  struct __gconv_step *result;

  if (gconv_cache == NULL)
    /* We have no cache available.  */
    return __GCONV_NODB;

  header = (const struct gconvcache_header *) gconv_cache;
  strtab = (char *) gconv_cache + header->string_offset;
  modtab = (const struct module_entry *) ((char *) gconv_cache
					  + header->module_offset);

  if (find_module_idx (fromset, &fromidx) != 0
      || (header->module_offset + (fromidx + 1) * sizeof (struct module_entry)
	  > cache_size))
    return __GCONV_NOCONV;
  from_module = &modtab[fromidx];

  if (find_module_idx (toset, &toidx) != 0
      || (header->module_offset + (toidx + 1) * sizeof (struct module_entry)
	  > cache_size))
    return __GCONV_NOCONV;
  to_module = &modtab[toidx];

  /* Avoid copy-only transformations if the user requests.   */
  if (__builtin_expect (flags & GCONV_AVOID_NOCONV, 0) && fromidx == toidx)
    return __GCONV_NOCONV;

  /* If there are special conversions available examine them first.  */
  if (fromidx != 0 && toidx != 0
      && __builtin_expect (from_module->extra_offset, 0) != 0)
    {
      /* Search through the list to see whether there is a module
	 matching the destination character set.  */
      const struct extra_entry *extra;

      /* Note the -1.  This is due to the offset added in iconvconfig.
	 See there for more explanations.  */
      extra = (const struct extra_entry *) ((char *) gconv_cache
					    + header->otherconv_offset
					    + from_module->extra_offset - 1);
      while (extra->module_cnt != 0
	     && extra->module[extra->module_cnt - 1].outname_offset != toidx)
	extra = (const struct extra_entry *) ((char *) extra
					      + sizeof (struct extra_entry)
					      + (extra->module_cnt
						 * sizeof (struct extra_entry_module)));

      if (extra->module_cnt != 0)
	{
	  /* Use the extra module.  First determine how many steps.  */
	  char *fromname;
	  int idx;

	  *nsteps = extra->module_cnt;
	  *handle = result =
	    (struct __gconv_step *) malloc (extra->module_cnt
					    * sizeof (struct __gconv_step));
	  if (result == NULL)
	    return __GCONV_NOMEM;

	  fromname = (char *) strtab + from_module->canonname_offset;
	  idx = 0;
	  do
	    {
	      result[idx].__from_name = fromname;
	      fromname = result[idx].__to_name =
		(char *) strtab + modtab[extra->module[idx].outname_offset].canonname_offset;

	      result[idx].__counter = 1;
	      result[idx].__data = NULL;

#ifndef STATIC_GCONV
	      if (strtab[extra->module[idx].dir_offset] != '\0')
		{
		  /* Load the module, return handle for it.  */
		  int res;

		  res = find_module (strtab + extra->module[idx].dir_offset,
				     strtab + extra->module[idx].name_offset,
				     &result[idx]);
		  if (__builtin_expect (res, __GCONV_OK) != __GCONV_OK)
		    {
		      /* Something went wrong.  */
		      free (result);
		      goto try_internal;
		    }
		}
	      else
#endif
		/* It's a builtin transformation.  */
		__gconv_get_builtin_trans (strtab
					   + extra->module[idx].name_offset,
					   &result[idx]);

	    }
	  while (++idx < extra->module_cnt);

	  return __GCONV_OK;
	}
    }

 try_internal:
  /* See whether we can convert via the INTERNAL charset.  */
  if ((fromidx != 0 && __builtin_expect (from_module->fromname_offset, 1) == 0)
      || (toidx != 0 && __builtin_expect (to_module->toname_offset, 1) == 0)
      || (fromidx == 0 && toidx == 0))
    /* Not possible.  Nothing we can do.  */
    return __GCONV_NOCONV;

  /* We will use up to two modules.  Always allocate room for two.  */
  result = (struct __gconv_step *) malloc (2 * sizeof (struct __gconv_step));
  if (result == NULL)
    return __GCONV_NOMEM;

  *handle = result;
  *nsteps = 0;

  /* Generate data structure for conversion to INTERNAL.  */
  if (fromidx != 0)
    {
      result[0].__from_name = (char *) strtab + from_module->canonname_offset;
      result[0].__to_name = (char *) "INTERNAL";

      result[0].__counter = 1;
      result[0].__data = NULL;

#ifndef STATIC_GCONV
      if (strtab[from_module->todir_offset] != '\0')
	{
	  /* Load the module, return handle for it.  */
	  int res = find_module (strtab + from_module->todir_offset,
				 strtab + from_module->toname_offset,
				 &result[0]);
	  if (__builtin_expect (res, __GCONV_OK) != __GCONV_OK)
	    {
	      /* Something went wrong.  */
	      free (result);
	      return res;
	    }
	}
      else
#endif
	/* It's a builtin transformation.  */
	__gconv_get_builtin_trans (strtab + from_module->toname_offset,
				   &result[0]);

      ++*nsteps;
    }

  /* Generate data structure for conversion from INTERNAL.  */
  if (toidx != 0)
    {
      int idx = *nsteps;

      result[idx].__from_name = (char *) "INTERNAL";
      result[idx].__to_name = (char *) strtab + to_module->canonname_offset;

      result[idx].__counter = 1;
      result[idx].__data = NULL;

#ifndef STATIC_GCONV
      if (strtab[to_module->fromdir_offset] != '\0')
	{
	  /* Load the module, return handle for it.  */
	  int res = find_module (strtab + to_module->fromdir_offset,
				 strtab + to_module->fromname_offset,
				 &result[idx]);
	  if (__builtin_expect (res, __GCONV_OK) != __GCONV_OK)
	    {
	      /* Something went wrong.  */
	      if (idx != 0)
		__gconv_release_step (&result[0]);
	      free (result);
	      return res;
	    }
	}
      else
#endif
	/* It's a builtin transformation.  */
	__gconv_get_builtin_trans (strtab + to_module->fromname_offset,
				   &result[idx]);

      ++*nsteps;
    }

  return __GCONV_OK;
}


/* Free memory allocated for the transformation record.  */
void
internal_function
__gconv_release_cache (struct __gconv_step *steps, size_t nsteps)
{
  if (gconv_cache != NULL)
    /* The only thing we have to deallocate is the record with the
       steps.  */
    free (steps);
}


/* Free all resources if necessary.  */
libc_freeres_fn (free_mem)
{
  if (cache_malloced)
    free (gconv_cache);
#ifdef _POSIX_MAPPED_FILES
  else
    __munmap (gconv_cache, cache_size);
#endif
}