iconv/gconv_cache.c

   1 /* Cache handling for iconv modules.
   2    Copyright (C) 2001, 2002 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 2001.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <dlfcn.h>
  22 #include <fcntl.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26 #include <sys/mman.h>
  27 #include <sys/stat.h>
  28
  29 #include <gconv_int.h>
  30 #include <iconvconfig.h>
  31
  32 #include "../intl/hash-string.h"
  33
  34 static void *gconv_cache;
  35 static size_t cache_size;
  36 static int cache_malloced;
  37
  38
  39 void *
  40 __gconv_get_cache (void)
  41 {
  42   return gconv_cache;
  43 }
  44
  45
  46 int
  47 internal_function
  48 __gconv_load_cache (void)
  49 {
  50   int fd;
  51   struct stat64 st;
  52   struct gconvcache_header *header;
  53
  54   /* We cannot use the cache if the GCONV_PATH environment variable is
  55      set.  */
  56   __gconv_path_envvar = getenv ("GCONV_PATH");
  57   if (__gconv_path_envvar != NULL)
  58     return -1;
  59
  60   /* See whether the cache file exists.  */
  61   fd = __open (GCONV_MODULES_CACHE, O_RDONLY);
  62   if (__builtin_expect (fd, 0) == -1)
  63     /* Not available.  */
  64     return -1;
  65
  66   /* Get information about the file.  */
  67   if (__builtin_expect (__fxstat64 (_STAT_VER, fd, &st), 0) < 0
  68       /* We do not have to start looking at the file if it cannot contain
  69          at least the cache header.  */
  70       || (size_t) st.st_size < sizeof (struct gconvcache_header))
  71     {
  72     close_and_exit:
  73       __close (fd);
  74       return -1;
  75     }
  76
  77   /* Make the file content available.  */
  78   cache_size = st.st_size;
  79 #ifdef _POSIX_MAPPED_FILES
  80   gconv_cache = __mmap (NULL, cache_size, PROT_READ, MAP_SHARED, fd, 0);
  81   if (__builtin_expect (gconv_cache == MAP_FAILED, 0))
  82 #endif
  83     {
  84       size_t already_read;
  85
  86       gconv_cache = malloc (cache_size);
  87       if (gconv_cache == NULL)
  88         goto close_and_exit;
  89
  90       already_read = 0;
  91       do
  92         {
  93           ssize_t n = __read (fd, (char *) gconv_cache + already_read,
  94                               cache_size - already_read);
  95           if (__builtin_expect (n, 0) == -1)
  96             {
  97               free (gconv_cache);
  98               gconv_cache = NULL;
  99               goto close_and_exit;
 100             }
 101
 102           already_read += n;
 103         }
 104       while (already_read < cache_size);
 105
 106       cache_malloced = 1;
 107     }
 108
 109   /* We don't need the file descriptor anymore.  */
 110   __close (fd);
 111
 112   /* Check the consistency.  */
 113   header = (struct gconvcache_header *) gconv_cache;
 114   if (__builtin_expect (header->magic, GCONVCACHE_MAGIC) != GCONVCACHE_MAGIC
 115       || __builtin_expect (header->string_offset >= cache_size, 0)
 116       || __builtin_expect (header->hash_offset >= cache_size, 0)
 117       || __builtin_expect (header->hash_size == 0, 0)
 118       || __builtin_expect ((header->hash_offset
 119                             + header->hash_size * sizeof (struct hash_entry))
 120                            > cache_size, 0)
 121       || __builtin_expect (header->module_offset >= cache_size, 0)
 122       || __builtin_expect (header->otherconv_offset > cache_size, 0))
 123     {
 124       if (cache_malloced)
 125         {
 126           free (gconv_cache);
 127           cache_malloced = 0;
 128         }
 129 #ifdef _POSIX_MAPPED_FILES
 130       else
 131         __munmap (gconv_cache, cache_size);
 132 #endif
 133       gconv_cache = NULL;
 134
 135       return -1;
 136     }
 137
 138   /* That worked.  */
 139   return 0;
 140 }
 141
 142
 143 static int
 144 internal_function
 145 find_module_idx (const char *str, size_t *idxp)
 146 {
 147   unsigned int idx;
 148   unsigned int hval;
 149   unsigned int hval2;
 150   const struct gconvcache_header *header;
 151   const char *strtab;
 152   const struct hash_entry *hashtab;
 153   unsigned int limit;
 154
 155   header = (const struct gconvcache_header *) gconv_cache;
 156   strtab = (char *) gconv_cache + header->string_offset;
 157   hashtab = (struct hash_entry *) ((char *) gconv_cache
 158                                    + header->hash_offset);
 159
 160   hval = hash_string (str);
 161   idx = hval % header->hash_size;
 162   hval2 = 1 + hval % (header->hash_size - 2);
 163
 164   limit = cache_size - header->string_offset;
 165   while (hashtab[idx].string_offset != 0)
 166     if (hashtab[idx].string_offset < limit
 167         && strcmp (str, strtab + hashtab[idx].string_offset) == 0)
 168       {
 169         *idxp = hashtab[idx].module_idx;
 170         return 0;
 171       }
 172     else
 173       if ((idx += hval2) >= header->hash_size)
 174         idx -= header->hash_size;
 175
 176   /* Nothing found.  */
 177   return -1;
 178 }
 179
 180
 181 #ifndef STATIC_GCONV
 182 static int
 183 internal_function
 184 find_module (const char *directory, const char *filename,
 185              struct __gconv_step *result)
 186 {
 187   size_t dirlen = strlen (directory);
 188   size_t fnamelen = strlen (filename) + 1;
 189   char fullname[dirlen + fnamelen];
 190   int status = __GCONV_NOCONV;
 191
 192   memcpy (__mempcpy (fullname, directory, dirlen), filename, fnamelen);
 193
 194   result->__shlib_handle = __gconv_find_shlib (fullname);
 195   if (result->__shlib_handle != NULL)
 196     {
 197       status = __GCONV_OK;
 198
 199       result->__modname = NULL;
 200       result->__fct = result->__shlib_handle->fct;
 201       result->__init_fct = result->__shlib_handle->init_fct;
 202       result->__end_fct = result->__shlib_handle->end_fct;
 203
 204       result->__data = NULL;
 205       if (result->__init_fct != NULL)
 206         status = DL_CALL_FCT (result->__init_fct, (result));
 207     }
 208
 209   return status;
 210 }
 211 #endif
 212
 213
 214 int
 215 internal_function
 216 __gconv_compare_alias_cache (const char *name1, const char *name2, int *result)
 217 {
 218   size_t name1_idx;
 219   size_t name2_idx;
 220
 221   if (gconv_cache == NULL)
 222     return -1;
 223
 224   if (find_module_idx (name1, &name1_idx) != 0
 225       || find_module_idx (name2, &name2_idx) != 0)
 226     *result = strcmp (name1, name2);
 227   else
 228     *result = (int) (name1_idx - name2_idx);
 229
 230   return 0;
 231 }
 232
 233
 234 int
 235 internal_function
 236 __gconv_lookup_cache (const char *toset, const char *fromset,
 237                       struct __gconv_step **handle, size_t *nsteps, int flags)
 238 {
 239   const struct gconvcache_header *header;
 240   const char *strtab;
 241   size_t fromidx;
 242   size_t toidx;
 243   const struct module_entry *modtab;
 244   const struct module_entry *from_module;
 245   const struct module_entry *to_module;
 246   struct __gconv_step *result;
 247
 248   if (gconv_cache == NULL)
 249     /* We have no cache available.  */
 250     return __GCONV_NODB;
 251
 252   header = (const struct gconvcache_header *) gconv_cache;
 253   strtab = (char *) gconv_cache + header->string_offset;
 254   modtab = (const struct module_entry *) ((char *) gconv_cache
 255                                           + header->module_offset);
 256
 257   if (find_module_idx (fromset, &fromidx) != 0
 258       || (header->module_offset + (fromidx + 1) * sizeof (struct module_entry)
 259           > cache_size))
 260     return __GCONV_NOCONV;
 261   from_module = &modtab[fromidx];
 262
 263   if (find_module_idx (toset, &toidx) != 0
 264       || (header->module_offset + (toidx + 1) * sizeof (struct module_entry)
 265           > cache_size))
 266     return __GCONV_NOCONV;
 267   to_module = &modtab[toidx];
 268
 269   /* Avoid copy-only transformations if the user requests.   */
 270   if (__builtin_expect (flags & GCONV_AVOID_NOCONV, 0) && fromidx == toidx)
 271     return __GCONV_NOCONV;
 272
 273   /* If there are special conversions available examine them first.  */
 274   if (fromidx != 0 && toidx != 0
 275       && __builtin_expect (from_module->extra_offset, 0) != 0)
 276     {
 277       /* Search through the list to see whether there is a module
 278          matching the destination character set.  */
 279       const struct extra_entry *extra;
 280
 281       /* Note the -1.  This is due to the offset added in iconvconfig.
 282          See there for more explanations.  */
 283       extra = (const struct extra_entry *) ((char *) gconv_cache
 284                                             + header->otherconv_offset
 285                                             + from_module->extra_offset - 1);
 286       while (extra->module_cnt != 0
 287              && extra->module[extra->module_cnt - 1].outname_offset != toidx)
 288         extra = (const struct extra_entry *) ((char *) extra
 289                                               + sizeof (struct extra_entry)
 290                                               + (extra->module_cnt
 291                                                  * sizeof (struct extra_entry_module)));
 292
 293       if (extra->module_cnt != 0)
 294         {
 295           /* Use the extra module.  First determine how many steps.  */
 296           char *fromname;
 297           int idx;
 298
 299           *nsteps = extra->module_cnt;
 300           *handle = result =
 301             (struct __gconv_step *) malloc (extra->module_cnt
 302                                             * sizeof (struct __gconv_step));
 303           if (result == NULL)
 304             return __GCONV_NOMEM;
 305
 306           fromname = (char *) strtab + from_module->canonname_offset;
 307           idx = 0;
 308           do
 309             {
 310               result[idx].__from_name = fromname;
 311               fromname = result[idx].__to_name =
 312                 (char *) strtab + modtab[extra->module[idx].outname_offset].canonname_offset;
 313
 314               result[idx].__counter = 1;
 315               result[idx].__data = NULL;
 316
 317 #ifndef STATIC_GCONV
 318               if (strtab[extra->module[idx].dir_offset] != '\0')
 319                 {
 320                   /* Load the module, return handle for it.  */
 321                   int res;
 322
 323                   res = find_module (strtab + extra->module[idx].dir_offset,
 324                                      strtab + extra->module[idx].name_offset,
 325                                      &result[idx]);
 326                   if (__builtin_expect (res, __GCONV_OK) != __GCONV_OK)
 327                     {
 328                       /* Something went wrong.  */
 329                       free (result);
 330                       goto try_internal;
 331                     }
 332                 }
 333               else
 334 #endif
 335                 /* It's a builtin transformation.  */
 336                 __gconv_get_builtin_trans (strtab
 337                                            + extra->module[idx].name_offset,
 338                                            &result[idx]);
 339
 340             }
 341           while (++idx < extra->module_cnt);
 342
 343           return __GCONV_OK;
 344         }
 345     }
 346
 347  try_internal:
 348   /* See whether we can convert via the INTERNAL charset.  */
 349   if ((fromidx != 0 && __builtin_expect (from_module->fromname_offset, 1) == 0)
 350       || (toidx != 0 && __builtin_expect (to_module->toname_offset, 1) == 0)
 351       || (fromidx == 0 && toidx == 0))
 352     /* Not possible.  Nothing we can do.  */
 353     return __GCONV_NOCONV;
 354
 355   /* We will use up to two modules.  Always allocate room for two.  */
 356   result = (struct __gconv_step *) malloc (2 * sizeof (struct __gconv_step));
 357   if (result == NULL)
 358     return __GCONV_NOMEM;
 359
 360   *handle = result;
 361   *nsteps = 0;
 362
 363   /* Generate data structure for conversion to INTERNAL.  */
 364   if (fromidx != 0)
 365     {
 366       result[0].__from_name = (char *) strtab + from_module->canonname_offset;
 367       result[0].__to_name = (char *) "INTERNAL";
 368
 369       result[0].__counter = 1;
 370       result[0].__data = NULL;
 371
 372 #ifndef STATIC_GCONV
 373       if (strtab[from_module->todir_offset] != '\0')
 374         {
 375           /* Load the module, return handle for it.  */
 376           int res = find_module (strtab + from_module->todir_offset,
 377                                  strtab + from_module->toname_offset,
 378                                  &result[0]);
 379           if (__builtin_expect (res, __GCONV_OK) != __GCONV_OK)
 380             {
 381               /* Something went wrong.  */
 382               free (result);
 383               return res;
 384             }
 385         }
 386       else
 387 #endif
 388         /* It's a builtin transformation.  */
 389         __gconv_get_builtin_trans (strtab + from_module->toname_offset,
 390                                    &result[0]);
 391
 392       ++*nsteps;
 393     }
 394
 395   /* Generate data structure for conversion from INTERNAL.  */
 396   if (toidx != 0)
 397     {
 398       int idx = *nsteps;
 399
 400       result[idx].__from_name = (char *) "INTERNAL";
 401       result[idx].__to_name = (char *) strtab + to_module->canonname_offset;
 402
 403       result[idx].__counter = 1;
 404       result[idx].__data = NULL;
 405
 406 #ifndef STATIC_GCONV
 407       if (strtab[to_module->fromdir_offset] != '\0')
 408         {
 409           /* Load the module, return handle for it.  */
 410           int res = find_module (strtab + to_module->fromdir_offset,
 411                                  strtab + to_module->fromname_offset,
 412                                  &result[idx]);
 413           if (__builtin_expect (res, __GCONV_OK) != __GCONV_OK)
 414             {
 415               /* Something went wrong.  */
 416               if (idx != 0)
 417                 __gconv_release_step (&result[0]);
 418               free (result);
 419               return res;
 420             }
 421         }
 422       else
 423 #endif
 424         /* It's a builtin transformation.  */
 425         __gconv_get_builtin_trans (strtab + to_module->fromname_offset,
 426                                    &result[idx]);
 427
 428       ++*nsteps;
 429     }
 430
 431   return __GCONV_OK;
 432 }
 433
 434
 435 /* Free memory allocated for the transformation record.  */
 436 void
 437 internal_function
 438 __gconv_release_cache (struct __gconv_step *steps, size_t nsteps)
 439 {
 440   if (gconv_cache != NULL)
 441     /* The only thing we have to deallocate is the record with the
 442        steps.  */
 443     free (steps);
 444 }
 445
 446
 447 /* Free all resources if necessary.  */
 448 static void __attribute__ ((unused))
 449 free_mem (void)
 450 {
 451   if (cache_malloced)
 452     free (gconv_cache);
 453 #ifdef _POSIX_MAPPED_FILES
 454   else
 455     __munmap (gconv_cache, cache_size);
 456 #endif
 457 }
 458
 459 text_set_element (__libc_subfreeres, free_mem);