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       /* These settings can be overridden by the init function.  */
 205       result->__btowc_fct = NULL;
 206       result->__data = NULL;
 207
 208       /* Call the init function.  */
 209       if (result->__init_fct != NULL)
 210         status = DL_CALL_FCT (result->__init_fct, (result));
 211     }
 212
 213   return status;
 214 }
 215 #endif
 216
 217
 218 int
 219 internal_function
 220 __gconv_compare_alias_cache (const char *name1, const char *name2, int *result)
 221 {
 222   size_t name1_idx;
 223   size_t name2_idx;
 224
 225   if (gconv_cache == NULL)
 226     return -1;
 227
 228   if (find_module_idx (name1, &name1_idx) != 0
 229       || find_module_idx (name2, &name2_idx) != 0)
 230     *result = strcmp (name1, name2);
 231   else
 232     *result = (int) (name1_idx - name2_idx);
 233
 234   return 0;
 235 }
 236
 237
 238 int
 239 internal_function
 240 __gconv_lookup_cache (const char *toset, const char *fromset,
 241                       struct __gconv_step **handle, size_t *nsteps, int flags)
 242 {
 243   const struct gconvcache_header *header;
 244   const char *strtab;
 245   size_t fromidx;
 246   size_t toidx;
 247   const struct module_entry *modtab;
 248   const struct module_entry *from_module;
 249   const struct module_entry *to_module;
 250   struct __gconv_step *result;
 251
 252   if (gconv_cache == NULL)
 253     /* We have no cache available.  */
 254     return __GCONV_NODB;
 255
 256   header = (const struct gconvcache_header *) gconv_cache;
 257   strtab = (char *) gconv_cache + header->string_offset;
 258   modtab = (const struct module_entry *) ((char *) gconv_cache
 259                                           + header->module_offset);
 260
 261   if (find_module_idx (fromset, &fromidx) != 0
 262       || (header->module_offset + (fromidx + 1) * sizeof (struct module_entry)
 263           > cache_size))
 264     return __GCONV_NOCONV;
 265   from_module = &modtab[fromidx];
 266
 267   if (find_module_idx (toset, &toidx) != 0
 268       || (header->module_offset + (toidx + 1) * sizeof (struct module_entry)
 269           > cache_size))
 270     return __GCONV_NOCONV;
 271   to_module = &modtab[toidx];
 272
 273   /* Avoid copy-only transformations if the user requests.   */
 274   if (__builtin_expect (flags & GCONV_AVOID_NOCONV, 0) && fromidx == toidx)
 275     return __GCONV_NOCONV;
 276
 277   /* If there are special conversions available examine them first.  */
 278   if (fromidx != 0 && toidx != 0
 279       && __builtin_expect (from_module->extra_offset, 0) != 0)
 280     {
 281       /* Search through the list to see whether there is a module
 282          matching the destination character set.  */
 283       const struct extra_entry *extra;
 284
 285       /* Note the -1.  This is due to the offset added in iconvconfig.
 286          See there for more explanations.  */
 287       extra = (const struct extra_entry *) ((char *) gconv_cache
 288                                             + header->otherconv_offset
 289                                             + from_module->extra_offset - 1);
 290       while (extra->module_cnt != 0
 291              && extra->module[extra->module_cnt - 1].outname_offset != toidx)
 292         extra = (const struct extra_entry *) ((char *) extra
 293                                               + sizeof (struct extra_entry)
 294                                               + (extra->module_cnt
 295                                                  * sizeof (struct extra_entry_module)));
 296
 297       if (extra->module_cnt != 0)
 298         {
 299           /* Use the extra module.  First determine how many steps.  */
 300           char *fromname;
 301           int idx;
 302
 303           *nsteps = extra->module_cnt;
 304           *handle = result =
 305             (struct __gconv_step *) malloc (extra->module_cnt
 306                                             * sizeof (struct __gconv_step));
 307           if (result == NULL)
 308             return __GCONV_NOMEM;
 309
 310           fromname = (char *) strtab + from_module->canonname_offset;
 311           idx = 0;
 312           do
 313             {
 314               result[idx].__from_name = fromname;
 315               fromname = result[idx].__to_name =
 316                 (char *) strtab + modtab[extra->module[idx].outname_offset].canonname_offset;
 317
 318               result[idx].__counter = 1;
 319               result[idx].__data = NULL;
 320
 321 #ifndef STATIC_GCONV
 322               if (strtab[extra->module[idx].dir_offset] != '\0')
 323                 {
 324                   /* Load the module, return handle for it.  */
 325                   int res;
 326
 327                   res = find_module (strtab + extra->module[idx].dir_offset,
 328                                      strtab + extra->module[idx].name_offset,
 329                                      &result[idx]);
 330                   if (__builtin_expect (res, __GCONV_OK) != __GCONV_OK)
 331                     {
 332                       /* Something went wrong.  */
 333                       free (result);
 334                       goto try_internal;
 335                     }
 336                 }
 337               else
 338 #endif
 339                 /* It's a builtin transformation.  */
 340                 __gconv_get_builtin_trans (strtab
 341                                            + extra->module[idx].name_offset,
 342                                            &result[idx]);
 343
 344             }
 345           while (++idx < extra->module_cnt);
 346
 347           return __GCONV_OK;
 348         }
 349     }
 350
 351  try_internal:
 352   /* See whether we can convert via the INTERNAL charset.  */
 353   if ((fromidx != 0 && __builtin_expect (from_module->fromname_offset, 1) == 0)
 354       || (toidx != 0 && __builtin_expect (to_module->toname_offset, 1) == 0)
 355       || (fromidx == 0 && toidx == 0))
 356     /* Not possible.  Nothing we can do.  */
 357     return __GCONV_NOCONV;
 358
 359   /* We will use up to two modules.  Always allocate room for two.  */
 360   result = (struct __gconv_step *) malloc (2 * sizeof (struct __gconv_step));
 361   if (result == NULL)
 362     return __GCONV_NOMEM;
 363
 364   *handle = result;
 365   *nsteps = 0;
 366
 367   /* Generate data structure for conversion to INTERNAL.  */
 368   if (fromidx != 0)
 369     {
 370       result[0].__from_name = (char *) strtab + from_module->canonname_offset;
 371       result[0].__to_name = (char *) "INTERNAL";
 372
 373       result[0].__counter = 1;
 374       result[0].__data = NULL;
 375
 376 #ifndef STATIC_GCONV
 377       if (strtab[from_module->todir_offset] != '\0')
 378         {
 379           /* Load the module, return handle for it.  */
 380           int res = find_module (strtab + from_module->todir_offset,
 381                                  strtab + from_module->toname_offset,
 382                                  &result[0]);
 383           if (__builtin_expect (res, __GCONV_OK) != __GCONV_OK)
 384             {
 385               /* Something went wrong.  */
 386               free (result);
 387               return res;
 388             }
 389         }
 390       else
 391 #endif
 392         /* It's a builtin transformation.  */
 393         __gconv_get_builtin_trans (strtab + from_module->toname_offset,
 394                                    &result[0]);
 395
 396       ++*nsteps;
 397     }
 398
 399   /* Generate data structure for conversion from INTERNAL.  */
 400   if (toidx != 0)
 401     {
 402       int idx = *nsteps;
 403
 404       result[idx].__from_name = (char *) "INTERNAL";
 405       result[idx].__to_name = (char *) strtab + to_module->canonname_offset;
 406
 407       result[idx].__counter = 1;
 408       result[idx].__data = NULL;
 409
 410 #ifndef STATIC_GCONV
 411       if (strtab[to_module->fromdir_offset] != '\0')
 412         {
 413           /* Load the module, return handle for it.  */
 414           int res = find_module (strtab + to_module->fromdir_offset,
 415                                  strtab + to_module->fromname_offset,
 416                                  &result[idx]);
 417           if (__builtin_expect (res, __GCONV_OK) != __GCONV_OK)
 418             {
 419               /* Something went wrong.  */
 420               if (idx != 0)
 421                 __gconv_release_step (&result[0]);
 422               free (result);
 423               return res;
 424             }
 425         }
 426       else
 427 #endif
 428         /* It's a builtin transformation.  */
 429         __gconv_get_builtin_trans (strtab + to_module->fromname_offset,
 430                                    &result[idx]);
 431
 432       ++*nsteps;
 433     }
 434
 435   return __GCONV_OK;
 436 }
 437
 438
 439 /* Free memory allocated for the transformation record.  */
 440 void
 441 internal_function
 442 __gconv_release_cache (struct __gconv_step *steps, size_t nsteps)
 443 {
 444   if (gconv_cache != NULL)
 445     /* The only thing we have to deallocate is the record with the
 446        steps.  */
 447     free (steps);
 448 }
 449
 450
 451 /* Free all resources if necessary.  */
 452 libc_freeres_fn (free_mem)
 453 {
 454   if (cache_malloced)
 455     free (gconv_cache);
 456 #ifdef _POSIX_MAPPED_FILES
 457   else
 458     __munmap (gconv_cache, cache_size);
 459 #endif
 460 }