iconv/gconv_conf.c

   1 /* Handle configuration data.
   2    Copyright (C) 1997-2017 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   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, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <assert.h>
  21 #include <ctype.h>
  22 #include <errno.h>
  23 #include <limits.h>
  24 #include <locale.h>
  25 #include <search.h>
  26 #include <stddef.h>
  27 #include <stdio.h>
  28 #include <stdio_ext.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <unistd.h>
  32 #include <sys/param.h>
  33
  34 #include <libc-lock.h>
  35 #include <gconv_int.h>
  36
  37
  38 /* This is the default path where we look for module lists.  */
  39 static const char default_gconv_path[] = GCONV_PATH;
  40
  41 /* The path elements, as determined by the __gconv_get_path function.
  42    All path elements end in a slash.  */
  43 struct path_elem *__gconv_path_elem;
  44 /* Maximum length of a single path element in __gconv_path_elem.  */
  45 size_t __gconv_max_path_elem_len;
  46
  47 /* We use the following struct if we couldn't allocate memory.  */
  48 static const struct path_elem empty_path_elem = { NULL, 0 };
  49
  50 /* Name of the file containing the module information in the directories
  51    along the path.  */
  52 static const char gconv_conf_filename[] = "gconv-modules";
  53
  54 /* Filename extension for the modules.  */
  55 #ifndef MODULE_EXT
  56 # define MODULE_EXT ".so"
  57 #endif
  58 static const char gconv_module_ext[] = MODULE_EXT;
  59
  60 /* We have a few builtin transformations.  */
  61 static struct gconv_module builtin_modules[] =
  62 {
  63 #define BUILTIN_TRANSFORMATION(From, To, Cost, Name, Fct, BtowcFct, \
  64                                MinF, MaxF, MinT, MaxT) \
  65   {                                                                           \
  66     .from_string = From,                                                      \
  67     .to_string = To,                                                          \
  68     .cost_hi = Cost,                                                          \
  69     .cost_lo = INT_MAX,                                                       \
  70     .module_name = Name                                                       \
  71   },
  72 #define BUILTIN_ALIAS(From, To)
  73
  74 #include "gconv_builtin.h"
  75
  76 #undef BUILTIN_TRANSFORMATION
  77 #undef BUILTIN_ALIAS
  78 };
  79
  80 static const char builtin_aliases[] =
  81 {
  82 #define BUILTIN_TRANSFORMATION(From, To, Cost, Name, Fct, BtowcFct, \
  83                                MinF, MaxF, MinT, MaxT)
  84 #define BUILTIN_ALIAS(From, To) From "\0" To "\0"
  85
  86 #include "gconv_builtin.h"
  87
  88 #undef BUILTIN_TRANSFORMATION
  89 #undef BUILTIN_ALIAS
  90 };
  91
  92 #include <libio/libioP.h>
  93 #define __getdelim(line, len, c, fp) _IO_getdelim (line, len, c, fp)
  94
  95
  96 /* Value of the GCONV_PATH environment variable.  */
  97 const char *__gconv_path_envvar;
  98
  99
 100 /* Test whether there is already a matching module known.  */
 101 static int
 102 internal_function
 103 detect_conflict (const char *alias)
 104 {
 105   struct gconv_module *node = __gconv_modules_db;
 106
 107   while (node != NULL)
 108     {
 109       int cmpres = strcmp (alias, node->from_string);
 110
 111       if (cmpres == 0)
 112         /* We have a conflict.  */
 113         return 1;
 114       else if (cmpres < 0)
 115         node = node->left;
 116       else
 117         node = node->right;
 118     }
 119
 120   return node != NULL;
 121 }
 122
 123
 124 /* The actual code to add aliases.  */
 125 static void
 126 add_alias2 (const char *from, const char *to, const char *wp, void *modules)
 127 {
 128   /* Test whether this alias conflicts with any available module.  */
 129   if (detect_conflict (from))
 130     /* It does conflict, don't add the alias.  */
 131     return;
 132
 133   struct gconv_alias *new_alias = (struct gconv_alias *)
 134     malloc (sizeof (struct gconv_alias) + (wp - from));
 135   if (new_alias != NULL)
 136     {
 137       void **inserted;
 138
 139       new_alias->fromname = memcpy ((char *) new_alias
 140                                     + sizeof (struct gconv_alias),
 141                                     from, wp - from);
 142       new_alias->toname = new_alias->fromname + (to - from);
 143
 144       inserted = (void **) __tsearch (new_alias, &__gconv_alias_db,
 145                                       __gconv_alias_compare);
 146       if (inserted == NULL || *inserted != new_alias)
 147         /* Something went wrong, free this entry.  */
 148         free (new_alias);
 149     }
 150 }
 151
 152
 153 /* Add new alias.  */
 154 static void
 155 add_alias (char *rp, void *modules)
 156 {
 157   /* We now expect two more string.  The strings are normalized
 158      (converted to UPPER case) and strored in the alias database.  */
 159   char *from, *to, *wp;
 160
 161   while (__isspace_l (*rp, _nl_C_locobj_ptr))
 162     ++rp;
 163   from = wp = rp;
 164   while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
 165     *wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);
 166   if (*rp == '\0')
 167     /* There is no `to' string on the line.  Ignore it.  */
 168     return;
 169   *wp++ = '\0';
 170   to = ++rp;
 171   while (__isspace_l (*rp, _nl_C_locobj_ptr))
 172     ++rp;
 173   while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
 174     *wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);
 175   if (to == wp)
 176     /* No `to' string, ignore the line.  */
 177     return;
 178   *wp++ = '\0';
 179
 180   add_alias2 (from, to, wp, modules);
 181 }
 182
 183
 184 /* Insert a data structure for a new module in the search tree.  */
 185 static void
 186 internal_function
 187 insert_module (struct gconv_module *newp, int tobefreed)
 188 {
 189   struct gconv_module **rootp = &__gconv_modules_db;
 190
 191   while (*rootp != NULL)
 192     {
 193       struct gconv_module *root = *rootp;
 194       int cmpres;
 195
 196       cmpres = strcmp (newp->from_string, root->from_string);
 197       if (cmpres == 0)
 198         {
 199           /* Both strings are identical.  Insert the string at the
 200              end of the `same' list if it is not already there.  */
 201           while (strcmp (newp->from_string, root->from_string) != 0
 202                  || strcmp (newp->to_string, root->to_string) != 0)
 203             {
 204               rootp = &root->same;
 205               root = *rootp;
 206               if (root == NULL)
 207                 break;
 208             }
 209
 210           if (root != NULL)
 211             {
 212               /* This is a no new conversion.  But maybe the cost is
 213                  better.  */
 214               if (newp->cost_hi < root->cost_hi
 215                   || (newp->cost_hi == root->cost_hi
 216                       && newp->cost_lo < root->cost_lo))
 217                 {
 218                   newp->left = root->left;
 219                   newp->right = root->right;
 220                   newp->same = root->same;
 221                   *rootp = newp;
 222
 223                   free (root);
 224                 }
 225               else if (tobefreed)
 226                 free (newp);
 227               return;
 228             }
 229
 230           break;
 231         }
 232       else if (cmpres < 0)
 233         rootp = &root->left;
 234       else
 235         rootp = &root->right;
 236     }
 237
 238   /* Plug in the new node here.  */
 239   *rootp = newp;
 240 }
 241
 242
 243 /* Add new module.  */
 244 static void
 245 internal_function
 246 add_module (char *rp, const char *directory, size_t dir_len, void **modules,
 247             size_t *nmodules, int modcounter)
 248 {
 249   /* We expect now
 250      1. `from' name
 251      2. `to' name
 252      3. filename of the module
 253      4. an optional cost value
 254   */
 255   struct gconv_alias fake_alias;
 256   struct gconv_module *new_module;
 257   char *from, *to, *module, *wp;
 258   int need_ext;
 259   int cost_hi;
 260
 261   while (__isspace_l (*rp, _nl_C_locobj_ptr))
 262     ++rp;
 263   from = rp;
 264   while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
 265     {
 266       *rp = __toupper_l (*rp, _nl_C_locobj_ptr);
 267       ++rp;
 268     }
 269   if (*rp == '\0')
 270     return;
 271   *rp++ = '\0';
 272   to = wp = rp;
 273   while (__isspace_l (*rp, _nl_C_locobj_ptr))
 274     ++rp;
 275   while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
 276     *wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);
 277   if (*rp == '\0')
 278     return;
 279   *wp++ = '\0';
 280   do
 281     ++rp;
 282   while (__isspace_l (*rp, _nl_C_locobj_ptr));
 283   module = wp;
 284   while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
 285     *wp++ = *rp++;
 286   if (*rp == '\0')
 287     {
 288       /* There is no cost, use one by default.  */
 289       *wp++ = '\0';
 290       cost_hi = 1;
 291     }
 292   else
 293     {
 294       /* There might be a cost value.  */
 295       char *endp;
 296
 297       *wp++ = '\0';
 298       cost_hi = strtol (rp, &endp, 10);
 299       if (rp == endp || cost_hi < 1)
 300         /* No useful information.  */
 301         cost_hi = 1;
 302     }
 303
 304   if (module[0] == '\0')
 305     /* No module name given.  */
 306     return;
 307   if (module[0] == '/')
 308     dir_len = 0;
 309
 310   /* See whether we must add the ending.  */
 311   need_ext = 0;
 312   if (wp - module < (ptrdiff_t) sizeof (gconv_module_ext)
 313       || memcmp (wp - sizeof (gconv_module_ext), gconv_module_ext,
 314                  sizeof (gconv_module_ext)) != 0)
 315     /* We must add the module extension.  */
 316     need_ext = sizeof (gconv_module_ext) - 1;
 317
 318   /* See whether we have already an alias with this name defined.  */
 319   fake_alias.fromname = strndupa (from, to - from);
 320
 321   if (__tfind (&fake_alias, &__gconv_alias_db, __gconv_alias_compare) != NULL)
 322     /* This module duplicates an alias.  */
 323     return;
 324
 325   new_module = (struct gconv_module *) calloc (1,
 326                                                sizeof (struct gconv_module)
 327                                                + (wp - from)
 328                                                + dir_len + need_ext);
 329   if (new_module != NULL)
 330     {
 331       char *tmp;
 332
 333       new_module->from_string = tmp = (char *) (new_module + 1);
 334       tmp = __mempcpy (tmp, from, to - from);
 335
 336       new_module->to_string = tmp;
 337       tmp = __mempcpy (tmp, to, module - to);
 338
 339       new_module->cost_hi = cost_hi;
 340       new_module->cost_lo = modcounter;
 341
 342       new_module->module_name = tmp;
 343
 344       if (dir_len != 0)
 345         tmp = __mempcpy (tmp, directory, dir_len);
 346
 347       tmp = __mempcpy (tmp, module, wp - module);
 348
 349       if (need_ext)
 350         memcpy (tmp - 1, gconv_module_ext, sizeof (gconv_module_ext));
 351
 352       /* Now insert the new module data structure in our search tree.  */
 353       insert_module (new_module, 1);
 354     }
 355 }
 356
 357
 358 /* Read the next configuration file.  */
 359 static void
 360 internal_function
 361 read_conf_file (const char *filename, const char *directory, size_t dir_len,
 362                 void **modules, size_t *nmodules)
 363 {
 364   /* Note the file is opened with cancellation in the I/O functions
 365      disabled.  */
 366   FILE *fp = fopen (filename, "rce");
 367   char *line = NULL;
 368   size_t line_len = 0;
 369   static int modcounter;
 370
 371   /* Don't complain if a file is not present or readable, simply silently
 372      ignore it.  */
 373   if (fp == NULL)
 374     return;
 375
 376   /* No threads reading from this stream.  */
 377   __fsetlocking (fp, FSETLOCKING_BYCALLER);
 378
 379   /* Process the known entries of the file.  Comments start with `#' and
 380      end with the end of the line.  Empty lines are ignored.  */
 381   while (!feof_unlocked (fp))
 382     {
 383       char *rp, *endp, *word;
 384       ssize_t n = __getdelim (&line, &line_len, '\n', fp);
 385       if (n < 0)
 386         /* An error occurred.  */
 387         break;
 388
 389       rp = line;
 390       /* Terminate the line (excluding comments or newline) by an NUL byte
 391          to simplify the following code.  */
 392       endp = strchr (rp, '#');
 393       if (endp != NULL)
 394         *endp = '\0';
 395       else
 396         if (rp[n - 1] == '\n')
 397           rp[n - 1] = '\0';
 398
 399       while (__isspace_l (*rp, _nl_C_locobj_ptr))
 400         ++rp;
 401
 402       /* If this is an empty line go on with the next one.  */
 403       if (rp == endp)
 404         continue;
 405
 406       word = rp;
 407       while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
 408         ++rp;
 409
 410       if (rp - word == sizeof ("alias") - 1
 411           && memcmp (word, "alias", sizeof ("alias") - 1) == 0)
 412         add_alias (rp, *modules);
 413       else if (rp - word == sizeof ("module") - 1
 414                && memcmp (word, "module", sizeof ("module") - 1) == 0)
 415         add_module (rp, directory, dir_len, modules, nmodules, modcounter++);
 416       /* else */
 417         /* Otherwise ignore the line.  */
 418     }
 419
 420   free (line);
 421
 422   fclose (fp);
 423 }
 424
 425
 426 /* Determine the directories we are looking for data in.  */
 427 void
 428 internal_function
 429 __gconv_get_path (void)
 430 {
 431   struct path_elem *result;
 432   __libc_lock_define_initialized (static, lock);
 433
 434   __libc_lock_lock (lock);
 435
 436   /* Make sure there wasn't a second thread doing it already.  */
 437   result = (struct path_elem *) __gconv_path_elem;
 438   if (result == NULL)
 439     {
 440       /* Determine the complete path first.  */
 441       char *gconv_path;
 442       size_t gconv_path_len;
 443       char *elem;
 444       char *oldp;
 445       char *cp;
 446       int nelems;
 447       char *cwd;
 448       size_t cwdlen;
 449
 450       if (__gconv_path_envvar == NULL)
 451         {
 452           /* No user-defined path.  Make a modifiable copy of the
 453              default path.  */
 454           gconv_path = strdupa (default_gconv_path);
 455           gconv_path_len = sizeof (default_gconv_path);
 456           cwd = NULL;
 457           cwdlen = 0;
 458         }
 459       else
 460         {
 461           /* Append the default path to the user-defined path.  */
 462           size_t user_len = strlen (__gconv_path_envvar);
 463
 464           gconv_path_len = user_len + 1 + sizeof (default_gconv_path);
 465           gconv_path = alloca (gconv_path_len);
 466           __mempcpy (__mempcpy (__mempcpy (gconv_path, __gconv_path_envvar,
 467                                            user_len),
 468                                 ":", 1),
 469                      default_gconv_path, sizeof (default_gconv_path));
 470           cwd = __getcwd (NULL, 0);
 471           cwdlen = __glibc_unlikely (cwd == NULL) ? 0 : strlen (cwd);
 472         }
 473       assert (default_gconv_path[0] == '/');
 474
 475       /* In a first pass we calculate the number of elements.  */
 476       oldp = NULL;
 477       cp = strchr (gconv_path, ':');
 478       nelems = 1;
 479       while (cp != NULL)
 480         {
 481           if (cp != oldp + 1)
 482             ++nelems;
 483           oldp = cp;
 484           cp =  strchr (cp + 1, ':');
 485         }
 486
 487       /* Allocate the memory for the result.  */
 488       result = (struct path_elem *) malloc ((nelems + 1)
 489                                             * sizeof (struct path_elem)
 490                                             + gconv_path_len + nelems
 491                                             + (nelems - 1) * (cwdlen + 1));
 492       if (result != NULL)
 493         {
 494           char *strspace = (char *) &result[nelems + 1];
 495           int n = 0;
 496
 497           /* Separate the individual parts.  */
 498           __gconv_max_path_elem_len = 0;
 499           elem = __strtok_r (gconv_path, ":", &gconv_path);
 500           assert (elem != NULL);
 501           do
 502             {
 503               result[n].name = strspace;
 504               if (elem[0] != '/')
 505                 {
 506                   assert (cwd != NULL);
 507                   strspace = __mempcpy (strspace, cwd, cwdlen);
 508                   *strspace++ = '/';
 509                 }
 510               strspace = __stpcpy (strspace, elem);
 511               if (strspace[-1] != '/')
 512                 *strspace++ = '/';
 513
 514               result[n].len = strspace - result[n].name;
 515               if (result[n].len > __gconv_max_path_elem_len)
 516                 __gconv_max_path_elem_len = result[n].len;
 517
 518               *strspace++ = '\0';
 519               ++n;
 520             }
 521           while ((elem = __strtok_r (NULL, ":", &gconv_path)) != NULL);
 522
 523           result[n].name = NULL;
 524           result[n].len = 0;
 525         }
 526
 527       __gconv_path_elem = result ?: (struct path_elem *) &empty_path_elem;
 528
 529       free (cwd);
 530     }
 531
 532   __libc_lock_unlock (lock);
 533 }
 534
 535
 536 /* Read all configuration files found in the user-specified and the default
 537    path.  */
 538 void
 539 attribute_hidden
 540 __gconv_read_conf (void)
 541 {
 542   void *modules = NULL;
 543   size_t nmodules = 0;
 544   int save_errno = errno;
 545   size_t cnt;
 546
 547   /* First see whether we should use the cache.  */
 548   if (__gconv_load_cache () == 0)
 549     {
 550       /* Yes, we are done.  */
 551       __set_errno (save_errno);
 552       return;
 553     }
 554
 555 #ifndef STATIC_GCONV
 556   /* Find out where we have to look.  */
 557   if (__gconv_path_elem == NULL)
 558     __gconv_get_path ();
 559
 560   for (cnt = 0; __gconv_path_elem[cnt].name != NULL; ++cnt)
 561     {
 562       const char *elem = __gconv_path_elem[cnt].name;
 563       size_t elem_len = __gconv_path_elem[cnt].len;
 564       char *filename;
 565
 566       /* No slash needs to be inserted between elem and gconv_conf_filename;
 567          elem already ends in a slash.  */
 568       filename = alloca (elem_len + sizeof (gconv_conf_filename));
 569       __mempcpy (__mempcpy (filename, elem, elem_len),
 570                  gconv_conf_filename, sizeof (gconv_conf_filename));
 571
 572       /* Read the next configuration file.  */
 573       read_conf_file (filename, elem, elem_len, &modules, &nmodules);
 574     }
 575 #endif
 576
 577   /* Add the internal modules.  */
 578   for (cnt = 0; cnt < sizeof (builtin_modules) / sizeof (builtin_modules[0]);
 579        ++cnt)
 580     {
 581       struct gconv_alias fake_alias;
 582
 583       fake_alias.fromname = (char *) builtin_modules[cnt].from_string;
 584
 585       if (__tfind (&fake_alias, &__gconv_alias_db, __gconv_alias_compare)
 586           != NULL)
 587         /* It'll conflict so don't add it.  */
 588         continue;
 589
 590       insert_module (&builtin_modules[cnt], 0);
 591     }
 592
 593   /* Add aliases for builtin conversions.  */
 594   const char *cp = builtin_aliases;
 595   do
 596     {
 597       const char *from = cp;
 598       const char *to = __rawmemchr (from, '\0') + 1;
 599       cp = __rawmemchr (to, '\0') + 1;
 600
 601       add_alias2 (from, to, cp, modules);
 602     }
 603   while (*cp != '\0');
 604
 605   /* Restore the error number.  */
 606   __set_errno (save_errno);
 607 }
 608
 609
 610
 611 /* Free all resources if necessary.  */
 612 libc_freeres_fn (free_mem)
 613 {
 614   if (__gconv_path_elem != NULL && __gconv_path_elem != &empty_path_elem)
 615     free ((void *) __gconv_path_elem);
 616 }