iconv/gconv_conf.c

   1 /* Handle configuration data.
   2    Copyright (C) 1997-2018 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 /* Type to represent search path.  */
  42 struct path_elem
  43 {
  44   const char *name;
  45   size_t len;
  46 };
  47
  48 /* The path elements, as determined by the __gconv_get_path function.
  49    All path elements end in a slash.  */
  50 struct path_elem *__gconv_path_elem;
  51 /* Maximum length of a single path element in __gconv_path_elem.  */
  52 size_t __gconv_max_path_elem_len;
  53
  54 /* We use the following struct if we couldn't allocate memory.  */
  55 static const struct path_elem empty_path_elem = { NULL, 0 };
  56
  57 /* Name of the file containing the module information in the directories
  58    along the path.  */
  59 static const char gconv_conf_filename[] = "gconv-modules";
  60
  61 /* Filename extension for the modules.  */
  62 #ifndef MODULE_EXT
  63 # define MODULE_EXT ".so"
  64 #endif
  65 static const char gconv_module_ext[] = MODULE_EXT;
  66
  67 /* We have a few builtin transformations.  */
  68 static struct gconv_module builtin_modules[] =
  69 {
  70 #define BUILTIN_TRANSFORMATION(From, To, Cost, Name, Fct, BtowcFct, \
  71                                MinF, MaxF, MinT, MaxT) \
  72   {                                                                           \
  73     .from_string = From,                                                      \
  74     .to_string = To,                                                          \
  75     .cost_hi = Cost,                                                          \
  76     .cost_lo = INT_MAX,                                                       \
  77     .module_name = Name                                                       \
  78   },
  79 #define BUILTIN_ALIAS(From, To)
  80
  81 #include "gconv_builtin.h"
  82
  83 #undef BUILTIN_TRANSFORMATION
  84 #undef BUILTIN_ALIAS
  85 };
  86
  87 static const char builtin_aliases[] =
  88 {
  89 #define BUILTIN_TRANSFORMATION(From, To, Cost, Name, Fct, BtowcFct, \
  90                                MinF, MaxF, MinT, MaxT)
  91 #define BUILTIN_ALIAS(From, To) From "\0" To "\0"
  92
  93 #include "gconv_builtin.h"
  94
  95 #undef BUILTIN_TRANSFORMATION
  96 #undef BUILTIN_ALIAS
  97 };
  98
  99 #include <libio/libioP.h>
 100 #define __getdelim(line, len, c, fp) _IO_getdelim (line, len, c, fp)
 101
 102
 103 /* Value of the GCONV_PATH environment variable.  */
 104 const char *__gconv_path_envvar;
 105
 106
 107 /* Test whether there is already a matching module known.  */
 108 static int
 109 detect_conflict (const char *alias)
 110 {
 111   struct gconv_module *node = __gconv_modules_db;
 112
 113   while (node != NULL)
 114     {
 115       int cmpres = strcmp (alias, node->from_string);
 116
 117       if (cmpres == 0)
 118         /* We have a conflict.  */
 119         return 1;
 120       else if (cmpres < 0)
 121         node = node->left;
 122       else
 123         node = node->right;
 124     }
 125
 126   return node != NULL;
 127 }
 128
 129
 130 /* The actual code to add aliases.  */
 131 static void
 132 add_alias2 (const char *from, const char *to, const char *wp, void *modules)
 133 {
 134   /* Test whether this alias conflicts with any available module.  */
 135   if (detect_conflict (from))
 136     /* It does conflict, don't add the alias.  */
 137     return;
 138
 139   struct gconv_alias *new_alias = (struct gconv_alias *)
 140     malloc (sizeof (struct gconv_alias) + (wp - from));
 141   if (new_alias != NULL)
 142     {
 143       void **inserted;
 144
 145       new_alias->fromname = memcpy ((char *) new_alias
 146                                     + sizeof (struct gconv_alias),
 147                                     from, wp - from);
 148       new_alias->toname = new_alias->fromname + (to - from);
 149
 150       inserted = (void **) __tsearch (new_alias, &__gconv_alias_db,
 151                                       __gconv_alias_compare);
 152       if (inserted == NULL || *inserted != new_alias)
 153         /* Something went wrong, free this entry.  */
 154         free (new_alias);
 155     }
 156 }
 157
 158
 159 /* Add new alias.  */
 160 static void
 161 add_alias (char *rp, void *modules)
 162 {
 163   /* We now expect two more string.  The strings are normalized
 164      (converted to UPPER case) and strored in the alias database.  */
 165   char *from, *to, *wp;
 166
 167   while (__isspace_l (*rp, _nl_C_locobj_ptr))
 168     ++rp;
 169   from = wp = rp;
 170   while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
 171     *wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);
 172   if (*rp == '\0')
 173     /* There is no `to' string on the line.  Ignore it.  */
 174     return;
 175   *wp++ = '\0';
 176   to = ++rp;
 177   while (__isspace_l (*rp, _nl_C_locobj_ptr))
 178     ++rp;
 179   while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
 180     *wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);
 181   if (to == wp)
 182     /* No `to' string, ignore the line.  */
 183     return;
 184   *wp++ = '\0';
 185
 186   add_alias2 (from, to, wp, modules);
 187 }
 188
 189
 190 /* Insert a data structure for a new module in the search tree.  */
 191 static void
 192 insert_module (struct gconv_module *newp, int tobefreed)
 193 {
 194   struct gconv_module **rootp = &__gconv_modules_db;
 195
 196   while (*rootp != NULL)
 197     {
 198       struct gconv_module *root = *rootp;
 199       int cmpres;
 200
 201       cmpres = strcmp (newp->from_string, root->from_string);
 202       if (cmpres == 0)
 203         {
 204           /* Both strings are identical.  Insert the string at the
 205              end of the `same' list if it is not already there.  */
 206           while (strcmp (newp->from_string, root->from_string) != 0
 207                  || strcmp (newp->to_string, root->to_string) != 0)
 208             {
 209               rootp = &root->same;
 210               root = *rootp;
 211               if (root == NULL)
 212                 break;
 213             }
 214
 215           if (root != NULL)
 216             {
 217               /* This is a no new conversion.  But maybe the cost is
 218                  better.  */
 219               if (newp->cost_hi < root->cost_hi
 220                   || (newp->cost_hi == root->cost_hi
 221                       && newp->cost_lo < root->cost_lo))
 222                 {
 223                   newp->left = root->left;
 224                   newp->right = root->right;
 225                   newp->same = root->same;
 226                   *rootp = newp;
 227
 228                   free (root);
 229                 }
 230               else if (tobefreed)
 231                 free (newp);
 232               return;
 233             }
 234
 235           break;
 236         }
 237       else if (cmpres < 0)
 238         rootp = &root->left;
 239       else
 240         rootp = &root->right;
 241     }
 242
 243   /* Plug in the new node here.  */
 244   *rootp = newp;
 245 }
 246
 247
 248 /* Add new module.  */
 249 static void
 250 add_module (char *rp, const char *directory, size_t dir_len, void **modules,
 251             size_t *nmodules, int modcounter)
 252 {
 253   /* We expect now
 254      1. `from' name
 255      2. `to' name
 256      3. filename of the module
 257      4. an optional cost value
 258   */
 259   struct gconv_alias fake_alias;
 260   struct gconv_module *new_module;
 261   char *from, *to, *module, *wp;
 262   int need_ext;
 263   int cost_hi;
 264
 265   while (__isspace_l (*rp, _nl_C_locobj_ptr))
 266     ++rp;
 267   from = rp;
 268   while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
 269     {
 270       *rp = __toupper_l (*rp, _nl_C_locobj_ptr);
 271       ++rp;
 272     }
 273   if (*rp == '\0')
 274     return;
 275   *rp++ = '\0';
 276   to = wp = rp;
 277   while (__isspace_l (*rp, _nl_C_locobj_ptr))
 278     ++rp;
 279   while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
 280     *wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);
 281   if (*rp == '\0')
 282     return;
 283   *wp++ = '\0';
 284   do
 285     ++rp;
 286   while (__isspace_l (*rp, _nl_C_locobj_ptr));
 287   module = wp;
 288   while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
 289     *wp++ = *rp++;
 290   if (*rp == '\0')
 291     {
 292       /* There is no cost, use one by default.  */
 293       *wp++ = '\0';
 294       cost_hi = 1;
 295     }
 296   else
 297     {
 298       /* There might be a cost value.  */
 299       char *endp;
 300
 301       *wp++ = '\0';
 302       cost_hi = strtol (rp, &endp, 10);
 303       if (rp == endp || cost_hi < 1)
 304         /* No useful information.  */
 305         cost_hi = 1;
 306     }
 307
 308   if (module[0] == '\0')
 309     /* No module name given.  */
 310     return;
 311   if (module[0] == '/')
 312     dir_len = 0;
 313
 314   /* See whether we must add the ending.  */
 315   need_ext = 0;
 316   if (wp - module < (ptrdiff_t) sizeof (gconv_module_ext)
 317       || memcmp (wp - sizeof (gconv_module_ext), gconv_module_ext,
 318                  sizeof (gconv_module_ext)) != 0)
 319     /* We must add the module extension.  */
 320     need_ext = sizeof (gconv_module_ext) - 1;
 321
 322   /* See whether we have already an alias with this name defined.  */
 323   fake_alias.fromname = strndupa (from, to - from);
 324
 325   if (__tfind (&fake_alias, &__gconv_alias_db, __gconv_alias_compare) != NULL)
 326     /* This module duplicates an alias.  */
 327     return;
 328
 329   new_module = (struct gconv_module *) calloc (1,
 330                                                sizeof (struct gconv_module)
 331                                                + (wp - from)
 332                                                + dir_len + need_ext);
 333   if (new_module != NULL)
 334     {
 335       char *tmp;
 336
 337       new_module->from_string = tmp = (char *) (new_module + 1);
 338       tmp = __mempcpy (tmp, from, to - from);
 339
 340       new_module->to_string = tmp;
 341       tmp = __mempcpy (tmp, to, module - to);
 342
 343       new_module->cost_hi = cost_hi;
 344       new_module->cost_lo = modcounter;
 345
 346       new_module->module_name = tmp;
 347
 348       if (dir_len != 0)
 349         tmp = __mempcpy (tmp, directory, dir_len);
 350
 351       tmp = __mempcpy (tmp, module, wp - module);
 352
 353       if (need_ext)
 354         memcpy (tmp - 1, gconv_module_ext, sizeof (gconv_module_ext));
 355
 356       /* Now insert the new module data structure in our search tree.  */
 357       insert_module (new_module, 1);
 358     }
 359 }
 360
 361
 362 /* Read the next configuration file.  */
 363 static void
 364 read_conf_file (const char *filename, const char *directory, size_t dir_len,
 365                 void **modules, size_t *nmodules)
 366 {
 367   /* Note the file is opened with cancellation in the I/O functions
 368      disabled.  */
 369   FILE *fp = fopen (filename, "rce");
 370   char *line = NULL;
 371   size_t line_len = 0;
 372   static int modcounter;
 373
 374   /* Don't complain if a file is not present or readable, simply silently
 375      ignore it.  */
 376   if (fp == NULL)
 377     return;
 378
 379   /* No threads reading from this stream.  */
 380   __fsetlocking (fp, FSETLOCKING_BYCALLER);
 381
 382   /* Process the known entries of the file.  Comments start with `#' and
 383      end with the end of the line.  Empty lines are ignored.  */
 384   while (!__feof_unlocked (fp))
 385     {
 386       char *rp, *endp, *word;
 387       ssize_t n = __getdelim (&line, &line_len, '\n', fp);
 388       if (n < 0)
 389         /* An error occurred.  */
 390         break;
 391
 392       rp = line;
 393       /* Terminate the line (excluding comments or newline) by an NUL byte
 394          to simplify the following code.  */
 395       endp = strchr (rp, '#');
 396       if (endp != NULL)
 397         *endp = '\0';
 398       else
 399         if (rp[n - 1] == '\n')
 400           rp[n - 1] = '\0';
 401
 402       while (__isspace_l (*rp, _nl_C_locobj_ptr))
 403         ++rp;
 404
 405       /* If this is an empty line go on with the next one.  */
 406       if (rp == endp)
 407         continue;
 408
 409       word = rp;
 410       while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
 411         ++rp;
 412
 413       if (rp - word == sizeof ("alias") - 1
 414           && memcmp (word, "alias", sizeof ("alias") - 1) == 0)
 415         add_alias (rp, *modules);
 416       else if (rp - word == sizeof ("module") - 1
 417                && memcmp (word, "module", sizeof ("module") - 1) == 0)
 418         add_module (rp, directory, dir_len, modules, nmodules, modcounter++);
 419       /* else */
 420         /* Otherwise ignore the line.  */
 421     }
 422
 423   free (line);
 424
 425   fclose (fp);
 426 }
 427
 428
 429 /* Determine the directories we are looking for data in.  */
 430 static void
 431 __gconv_get_path (void)
 432 {
 433   struct path_elem *result;
 434   __libc_lock_define_initialized (static, lock);
 435
 436   __libc_lock_lock (lock);
 437
 438   /* Make sure there wasn't a second thread doing it already.  */
 439   result = (struct path_elem *) __gconv_path_elem;
 440   if (result == NULL)
 441     {
 442       /* Determine the complete path first.  */
 443       char *gconv_path;
 444       size_t gconv_path_len;
 445       char *elem;
 446       char *oldp;
 447       char *cp;
 448       int nelems;
 449       char *cwd;
 450       size_t cwdlen;
 451
 452       if (__gconv_path_envvar == NULL)
 453         {
 454           /* No user-defined path.  Make a modifiable copy of the
 455              default path.  */
 456           gconv_path = strdupa (default_gconv_path);
 457           gconv_path_len = sizeof (default_gconv_path);
 458           cwd = NULL;
 459           cwdlen = 0;
 460         }
 461       else
 462         {
 463           /* Append the default path to the user-defined path.  */
 464           size_t user_len = strlen (__gconv_path_envvar);
 465
 466           gconv_path_len = user_len + 1 + sizeof (default_gconv_path);
 467           gconv_path = alloca (gconv_path_len);
 468           __mempcpy (__mempcpy (__mempcpy (gconv_path, __gconv_path_envvar,
 469                                            user_len),
 470                                 ":", 1),
 471                      default_gconv_path, sizeof (default_gconv_path));
 472           cwd = __getcwd (NULL, 0);
 473           cwdlen = __glibc_unlikely (cwd == NULL) ? 0 : strlen (cwd);
 474         }
 475       assert (default_gconv_path[0] == '/');
 476
 477       /* In a first pass we calculate the number of elements.  */
 478       oldp = NULL;
 479       cp = strchr (gconv_path, ':');
 480       nelems = 1;
 481       while (cp != NULL)
 482         {
 483           if (cp != oldp + 1)
 484             ++nelems;
 485           oldp = cp;
 486           cp =  strchr (cp + 1, ':');
 487         }
 488
 489       /* Allocate the memory for the result.  */
 490       result = (struct path_elem *) malloc ((nelems + 1)
 491                                             * sizeof (struct path_elem)
 492                                             + gconv_path_len + nelems
 493                                             + (nelems - 1) * (cwdlen + 1));
 494       if (result != NULL)
 495         {
 496           char *strspace = (char *) &result[nelems + 1];
 497           int n = 0;
 498
 499           /* Separate the individual parts.  */
 500           __gconv_max_path_elem_len = 0;
 501           elem = __strtok_r (gconv_path, ":", &gconv_path);
 502           assert (elem != NULL);
 503           do
 504             {
 505               result[n].name = strspace;
 506               if (elem[0] != '/')
 507                 {
 508                   assert (cwd != NULL);
 509                   strspace = __mempcpy (strspace, cwd, cwdlen);
 510                   *strspace++ = '/';
 511                 }
 512               strspace = __stpcpy (strspace, elem);
 513               if (strspace[-1] != '/')
 514                 *strspace++ = '/';
 515
 516               result[n].len = strspace - result[n].name;
 517               if (result[n].len > __gconv_max_path_elem_len)
 518                 __gconv_max_path_elem_len = result[n].len;
 519
 520               *strspace++ = '\0';
 521               ++n;
 522             }
 523           while ((elem = __strtok_r (NULL, ":", &gconv_path)) != NULL);
 524
 525           result[n].name = NULL;
 526           result[n].len = 0;
 527         }
 528
 529       __gconv_path_elem = result ?: (struct path_elem *) &empty_path_elem;
 530
 531       free (cwd);
 532     }
 533
 534   __libc_lock_unlock (lock);
 535 }
 536
 537
 538 /* Read all configuration files found in the user-specified and the default
 539    path.  */
 540 void
 541 attribute_hidden
 542 __gconv_read_conf (void)
 543 {
 544   void *modules = NULL;
 545   size_t nmodules = 0;
 546   int save_errno = errno;
 547   size_t cnt;
 548
 549   /* First see whether we should use the cache.  */
 550   if (__gconv_load_cache () == 0)
 551     {
 552       /* Yes, we are done.  */
 553       __set_errno (save_errno);
 554       return;
 555     }
 556
 557 #ifndef STATIC_GCONV
 558   /* Find out where we have to look.  */
 559   if (__gconv_path_elem == NULL)
 560     __gconv_get_path ();
 561
 562   for (cnt = 0; __gconv_path_elem[cnt].name != NULL; ++cnt)
 563     {
 564       const char *elem = __gconv_path_elem[cnt].name;
 565       size_t elem_len = __gconv_path_elem[cnt].len;
 566       char *filename;
 567
 568       /* No slash needs to be inserted between elem and gconv_conf_filename;
 569          elem already ends in a slash.  */
 570       filename = alloca (elem_len + sizeof (gconv_conf_filename));
 571       __mempcpy (__mempcpy (filename, elem, elem_len),
 572                  gconv_conf_filename, sizeof (gconv_conf_filename));
 573
 574       /* Read the next configuration file.  */
 575       read_conf_file (filename, elem, elem_len, &modules, &nmodules);
 576     }
 577 #endif
 578
 579   /* Add the internal modules.  */
 580   for (cnt = 0; cnt < sizeof (builtin_modules) / sizeof (builtin_modules[0]);
 581        ++cnt)
 582     {
 583       struct gconv_alias fake_alias;
 584
 585       fake_alias.fromname = (char *) builtin_modules[cnt].from_string;
 586
 587       if (__tfind (&fake_alias, &__gconv_alias_db, __gconv_alias_compare)
 588           != NULL)
 589         /* It'll conflict so don't add it.  */
 590         continue;
 591
 592       insert_module (&builtin_modules[cnt], 0);
 593     }
 594
 595   /* Add aliases for builtin conversions.  */
 596   const char *cp = builtin_aliases;
 597   do
 598     {
 599       const char *from = cp;
 600       const char *to = __rawmemchr (from, '\0') + 1;
 601       cp = __rawmemchr (to, '\0') + 1;
 602
 603       add_alias2 (from, to, cp, modules);
 604     }
 605   while (*cp != '\0');
 606
 607   /* Restore the error number.  */
 608   __set_errno (save_errno);
 609 }
 610
 611
 612
 613 /* Free all resources if necessary.  */
 614 libc_freeres_fn (free_mem)
 615 {
 616   if (__gconv_path_elem != NULL && __gconv_path_elem != &empty_path_elem)
 617     free ((void *) __gconv_path_elem);
 618 }