gnulib/import/localcharset.c

   1 /* Determine a canonical name for the current locale's character encoding.
   2
   3    Copyright (C) 2000-2006, 2008-2016 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3, or (at your option)
   8    any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License along
  16    with this program; if not, see <http://www.gnu.org/licenses/>.  */
  17
  18 /* Written by Bruno Haible <bruno@clisp.org>.  */
  19
  20 #include <config.h>
  21
  22 /* Specification.  */
  23 #include "localcharset.h"
  24
  25 #include <fcntl.h>
  26 #include <stddef.h>
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <stdlib.h>
  30
  31 #if defined __APPLE__ && defined __MACH__ && HAVE_LANGINFO_CODESET
  32 # define DARWIN7 /* Darwin 7 or newer, i.e. Mac OS X 10.3 or newer */
  33 #endif
  34
  35 #if defined _WIN32 || defined __WIN32__
  36 # define WINDOWS_NATIVE
  37 # include <locale.h>
  38 #endif
  39
  40 #if defined __EMX__
  41 /* Assume EMX program runs on OS/2, even if compiled under DOS.  */
  42 # ifndef OS2
  43 #  define OS2
  44 # endif
  45 #endif
  46
  47 #if !defined WINDOWS_NATIVE
  48 # include <unistd.h>
  49 # if HAVE_LANGINFO_CODESET
  50 #  include <langinfo.h>
  51 # else
  52 #  if 0 /* see comment below */
  53 #   include <locale.h>
  54 #  endif
  55 # endif
  56 # ifdef __CYGWIN__
  57 #  define WIN32_LEAN_AND_MEAN
  58 #  include <windows.h>
  59 # endif
  60 #elif defined WINDOWS_NATIVE
  61 # define WIN32_LEAN_AND_MEAN
  62 # include <windows.h>
  63 #endif
  64 #if defined OS2
  65 # define INCL_DOS
  66 # include <os2.h>
  67 #endif
  68
  69 /* For MB_CUR_MAX_L */
  70 #if defined DARWIN7
  71 # include <xlocale.h>
  72 #endif
  73
  74 #if ENABLE_RELOCATABLE
  75 # include "relocatable.h"
  76 #else
  77 # define relocate(pathname) (pathname)
  78 #endif
  79
  80 /* Get LIBDIR.  */
  81 #ifndef LIBDIR
  82 # include "configmake.h"
  83 #endif
  84
  85 /* Define O_NOFOLLOW to 0 on platforms where it does not exist.  */
  86 #ifndef O_NOFOLLOW
  87 # define O_NOFOLLOW 0
  88 #endif
  89
  90 #if defined _WIN32 || defined __WIN32__ || defined __CYGWIN__ || defined __EMX__ || defined __DJGPP__
  91   /* Native Windows, Cygwin, OS/2, DOS */
  92 # define ISSLASH(C) ((C) == '/' || (C) == '\\')
  93 #endif
  94
  95 #ifndef DIRECTORY_SEPARATOR
  96 # define DIRECTORY_SEPARATOR '/'
  97 #endif
  98
  99 #ifndef ISSLASH
 100 # define ISSLASH(C) ((C) == DIRECTORY_SEPARATOR)
 101 #endif
 102
 103 #if HAVE_DECL_GETC_UNLOCKED
 104 # undef getc
 105 # define getc getc_unlocked
 106 #endif
 107
 108 /* The following static variable is declared 'volatile' to avoid a
 109    possible multithread problem in the function get_charset_aliases. If we
 110    are running in a threaded environment, and if two threads initialize
 111    'charset_aliases' simultaneously, both will produce the same value,
 112    and everything will be ok if the two assignments to 'charset_aliases'
 113    are atomic. But I don't know what will happen if the two assignments mix.  */
 114 #if __STDC__ != 1
 115 # define volatile /* empty */
 116 #endif
 117 /* Pointer to the contents of the charset.alias file, if it has already been
 118    read, else NULL.  Its format is:
 119    ALIAS_1 '\0' CANONICAL_1 '\0' ... ALIAS_n '\0' CANONICAL_n '\0' '\0'  */
 120 static const char * volatile charset_aliases;
 121
 122 /* Return a pointer to the contents of the charset.alias file.  */
 123 static const char *
 124 get_charset_aliases (void)
 125 {
 126   const char *cp;
 127
 128   cp = charset_aliases;
 129   if (cp == NULL)
 130     {
 131 #if !(defined DARWIN7 || defined VMS || defined WINDOWS_NATIVE || defined __CYGWIN__ || defined OS2)
 132       const char *dir;
 133       const char *base = "charset.alias";
 134       char *file_name;
 135
 136       /* Make it possible to override the charset.alias location.  This is
 137          necessary for running the testsuite before "make install".  */
 138       dir = getenv ("CHARSETALIASDIR");
 139       if (dir == NULL || dir[0] == '\0')
 140         dir = relocate (LIBDIR);
 141
 142       /* Concatenate dir and base into freshly allocated file_name.  */
 143       {
 144         size_t dir_len = strlen (dir);
 145         size_t base_len = strlen (base);
 146         int add_slash = (dir_len > 0 && !ISSLASH (dir[dir_len - 1]));
 147         file_name = (char *) malloc (dir_len + add_slash + base_len + 1);
 148         if (file_name != NULL)
 149           {
 150             memcpy (file_name, dir, dir_len);
 151             if (add_slash)
 152               file_name[dir_len] = DIRECTORY_SEPARATOR;
 153             memcpy (file_name + dir_len + add_slash, base, base_len + 1);
 154           }
 155       }
 156
 157       if (file_name == NULL)
 158         /* Out of memory.  Treat the file as empty.  */
 159         cp = "";
 160       else
 161         {
 162           int fd;
 163
 164           /* Open the file.  Reject symbolic links on platforms that support
 165              O_NOFOLLOW.  This is a security feature.  Without it, an attacker
 166              could retrieve parts of the contents (namely, the tail of the
 167              first line that starts with "* ") of an arbitrary file by placing
 168              a symbolic link to that file under the name "charset.alias" in
 169              some writable directory and defining the environment variable
 170              CHARSETALIASDIR to point to that directory.  */
 171           fd = open (file_name,
 172                      O_RDONLY | (HAVE_WORKING_O_NOFOLLOW ? O_NOFOLLOW : 0));
 173           if (fd < 0)
 174             /* File not found.  Treat it as empty.  */
 175             cp = "";
 176           else
 177             {
 178               FILE *fp;
 179
 180               fp = fdopen (fd, "r");
 181               if (fp == NULL)
 182                 {
 183                   /* Out of memory.  Treat the file as empty.  */
 184                   close (fd);
 185                   cp = "";
 186                 }
 187               else
 188                 {
 189                   /* Parse the file's contents.  */
 190                   char *res_ptr = NULL;
 191                   size_t res_size = 0;
 192
 193                   for (;;)
 194                     {
 195                       int c;
 196                       char buf1[50+1];
 197                       char buf2[50+1];
 198                       size_t l1, l2;
 199                       char *old_res_ptr;
 200
 201                       c = getc (fp);
 202                       if (c == EOF)
 203                         break;
 204                       if (c == '\n' || c == ' ' || c == '\t')
 205                         continue;
 206                       if (c == '#')
 207                         {
 208                           /* Skip comment, to end of line.  */
 209                           do
 210                             c = getc (fp);
 211                           while (!(c == EOF || c == '\n'));
 212                           if (c == EOF)
 213                             break;
 214                           continue;
 215                         }
 216                       ungetc (c, fp);
 217                       if (fscanf (fp, "%50s %50s", buf1, buf2) < 2)
 218                         break;
 219                       l1 = strlen (buf1);
 220                       l2 = strlen (buf2);
 221                       old_res_ptr = res_ptr;
 222                       if (res_size == 0)
 223                         {
 224                           res_size = l1 + 1 + l2 + 1;
 225                           res_ptr = (char *) malloc (res_size + 1);
 226                         }
 227                       else
 228                         {
 229                           res_size += l1 + 1 + l2 + 1;
 230                           res_ptr = (char *) realloc (res_ptr, res_size + 1);
 231                         }
 232                       if (res_ptr == NULL)
 233                         {
 234                           /* Out of memory. */
 235                           res_size = 0;
 236                           free (old_res_ptr);
 237                           break;
 238                         }
 239                       strcpy (res_ptr + res_size - (l2 + 1) - (l1 + 1), buf1);
 240                       strcpy (res_ptr + res_size - (l2 + 1), buf2);
 241                     }
 242                   fclose (fp);
 243                   if (res_size == 0)
 244                     cp = "";
 245                   else
 246                     {
 247                       *(res_ptr + res_size) = '\0';
 248                       cp = res_ptr;
 249                     }
 250                 }
 251             }
 252
 253           free (file_name);
 254         }
 255
 256 #else
 257
 258 # if defined DARWIN7
 259       /* To avoid the trouble of installing a file that is shared by many
 260          GNU packages -- many packaging systems have problems with this --,
 261          simply inline the aliases here.  */
 262       cp = "ISO8859-1" "\0" "ISO-8859-1" "\0"
 263            "ISO8859-2" "\0" "ISO-8859-2" "\0"
 264            "ISO8859-4" "\0" "ISO-8859-4" "\0"
 265            "ISO8859-5" "\0" "ISO-8859-5" "\0"
 266            "ISO8859-7" "\0" "ISO-8859-7" "\0"
 267            "ISO8859-9" "\0" "ISO-8859-9" "\0"
 268            "ISO8859-13" "\0" "ISO-8859-13" "\0"
 269            "ISO8859-15" "\0" "ISO-8859-15" "\0"
 270            "KOI8-R" "\0" "KOI8-R" "\0"
 271            "KOI8-U" "\0" "KOI8-U" "\0"
 272            "CP866" "\0" "CP866" "\0"
 273            "CP949" "\0" "CP949" "\0"
 274            "CP1131" "\0" "CP1131" "\0"
 275            "CP1251" "\0" "CP1251" "\0"
 276            "eucCN" "\0" "GB2312" "\0"
 277            "GB2312" "\0" "GB2312" "\0"
 278            "eucJP" "\0" "EUC-JP" "\0"
 279            "eucKR" "\0" "EUC-KR" "\0"
 280            "Big5" "\0" "BIG5" "\0"
 281            "Big5HKSCS" "\0" "BIG5-HKSCS" "\0"
 282            "GBK" "\0" "GBK" "\0"
 283            "GB18030" "\0" "GB18030" "\0"
 284            "SJIS" "\0" "SHIFT_JIS" "\0"
 285            "ARMSCII-8" "\0" "ARMSCII-8" "\0"
 286            "PT154" "\0" "PT154" "\0"
 287          /*"ISCII-DEV" "\0" "?" "\0"*/
 288            "*" "\0" "UTF-8" "\0";
 289 # endif
 290
 291 # if defined VMS
 292       /* To avoid the troubles of an extra file charset.alias_vms in the
 293          sources of many GNU packages, simply inline the aliases here.  */
 294       /* The list of encodings is taken from the OpenVMS 7.3-1 documentation
 295          "Compaq C Run-Time Library Reference Manual for OpenVMS systems"
 296          section 10.7 "Handling Different Character Sets".  */
 297       cp = "ISO8859-1" "\0" "ISO-8859-1" "\0"
 298            "ISO8859-2" "\0" "ISO-8859-2" "\0"
 299            "ISO8859-5" "\0" "ISO-8859-5" "\0"
 300            "ISO8859-7" "\0" "ISO-8859-7" "\0"
 301            "ISO8859-8" "\0" "ISO-8859-8" "\0"
 302            "ISO8859-9" "\0" "ISO-8859-9" "\0"
 303            /* Japanese */
 304            "eucJP" "\0" "EUC-JP" "\0"
 305            "SJIS" "\0" "SHIFT_JIS" "\0"
 306            "DECKANJI" "\0" "DEC-KANJI" "\0"
 307            "SDECKANJI" "\0" "EUC-JP" "\0"
 308            /* Chinese */
 309            "eucTW" "\0" "EUC-TW" "\0"
 310            "DECHANYU" "\0" "DEC-HANYU" "\0"
 311            "DECHANZI" "\0" "GB2312" "\0"
 312            /* Korean */
 313            "DECKOREAN" "\0" "EUC-KR" "\0";
 314 # endif
 315
 316 # if defined WINDOWS_NATIVE || defined __CYGWIN__
 317       /* To avoid the troubles of installing a separate file in the same
 318          directory as the DLL and of retrieving the DLL's directory at
 319          runtime, simply inline the aliases here.  */
 320
 321       cp = "CP936" "\0" "GBK" "\0"
 322            "CP1361" "\0" "JOHAB" "\0"
 323            "CP20127" "\0" "ASCII" "\0"
 324            "CP20866" "\0" "KOI8-R" "\0"
 325            "CP20936" "\0" "GB2312" "\0"
 326            "CP21866" "\0" "KOI8-RU" "\0"
 327            "CP28591" "\0" "ISO-8859-1" "\0"
 328            "CP28592" "\0" "ISO-8859-2" "\0"
 329            "CP28593" "\0" "ISO-8859-3" "\0"
 330            "CP28594" "\0" "ISO-8859-4" "\0"
 331            "CP28595" "\0" "ISO-8859-5" "\0"
 332            "CP28596" "\0" "ISO-8859-6" "\0"
 333            "CP28597" "\0" "ISO-8859-7" "\0"
 334            "CP28598" "\0" "ISO-8859-8" "\0"
 335            "CP28599" "\0" "ISO-8859-9" "\0"
 336            "CP28605" "\0" "ISO-8859-15" "\0"
 337            "CP38598" "\0" "ISO-8859-8" "\0"
 338            "CP51932" "\0" "EUC-JP" "\0"
 339            "CP51936" "\0" "GB2312" "\0"
 340            "CP51949" "\0" "EUC-KR" "\0"
 341            "CP51950" "\0" "EUC-TW" "\0"
 342            "CP54936" "\0" "GB18030" "\0"
 343            "CP65001" "\0" "UTF-8" "\0";
 344 # endif
 345 # if defined OS2
 346       /* To avoid the troubles of installing a separate file in the same
 347          directory as the DLL and of retrieving the DLL's directory at
 348          runtime, simply inline the aliases here.  */
 349
 350       /* The list of encodings is taken from "List of OS/2 Codepages"
 351          by Alex Taylor:
 352          <http://altsan.org/os2/toolkits/uls/index.html#codepages>.
 353          See also "IBM Globalization - Code page identifiers":
 354          <http://www-01.ibm.com/software/globalization/cp/cp_cpgid.html>.  */
 355       cp = "CP813" "\0" "ISO-8859-7" "\0"
 356            "CP878" "\0" "KOI8-R" "\0"
 357            "CP819" "\0" "ISO-8859-1" "\0"
 358            "CP912" "\0" "ISO-8859-2" "\0"
 359            "CP913" "\0" "ISO-8859-3" "\0"
 360            "CP914" "\0" "ISO-8859-4" "\0"
 361            "CP915" "\0" "ISO-8859-5" "\0"
 362            "CP916" "\0" "ISO-8859-8" "\0"
 363            "CP920" "\0" "ISO-8859-9" "\0"
 364            "CP921" "\0" "ISO-8859-13" "\0"
 365            "CP923" "\0" "ISO-8859-15" "\0"
 366            "CP954" "\0" "EUC-JP" "\0"
 367            "CP964" "\0" "EUC-TW" "\0"
 368            "CP970" "\0" "EUC-KR" "\0"
 369            "CP1089" "\0" "ISO-8859-6" "\0"
 370            "CP1208" "\0" "UTF-8" "\0"
 371            "CP1381" "\0" "GB2312" "\0"
 372            "CP1386" "\0" "GBK" "\0"
 373            "CP3372" "\0" "EUC-JP" "\0";
 374 # endif
 375 #endif
 376
 377       charset_aliases = cp;
 378     }
 379
 380   return cp;
 381 }
 382
 383 /* Determine the current locale's character encoding, and canonicalize it
 384    into one of the canonical names listed in config.charset.
 385    The result must not be freed; it is statically allocated.
 386    If the canonical name cannot be determined, the result is a non-canonical
 387    name.  */
 388
 389 #ifdef STATIC
 390 STATIC
 391 #endif
 392 const char *
 393 locale_charset (void)
 394 {
 395   const char *codeset;
 396   const char *aliases;
 397
 398 #if !(defined WINDOWS_NATIVE || defined OS2)
 399
 400 # if HAVE_LANGINFO_CODESET
 401
 402   /* Most systems support nl_langinfo (CODESET) nowadays.  */
 403   codeset = nl_langinfo (CODESET);
 404
 405 #  ifdef __CYGWIN__
 406   /* Cygwin < 1.7 does not have locales.  nl_langinfo (CODESET) always
 407      returns "US-ASCII".  Return the suffix of the locale name from the
 408      environment variables (if present) or the codepage as a number.  */
 409   if (codeset != NULL && strcmp (codeset, "US-ASCII") == 0)
 410     {
 411       const char *locale;
 412       static char buf[2 + 10 + 1];
 413
 414       locale = getenv ("LC_ALL");
 415       if (locale == NULL || locale[0] == '\0')
 416         {
 417           locale = getenv ("LC_CTYPE");
 418           if (locale == NULL || locale[0] == '\0')
 419             locale = getenv ("LANG");
 420         }
 421       if (locale != NULL && locale[0] != '\0')
 422         {
 423           /* If the locale name contains an encoding after the dot, return
 424              it.  */
 425           const char *dot = strchr (locale, '.');
 426
 427           if (dot != NULL)
 428             {
 429               const char *modifier;
 430
 431               dot++;
 432               /* Look for the possible @... trailer and remove it, if any.  */
 433               modifier = strchr (dot, '@');
 434               if (modifier == NULL)
 435                 return dot;
 436               if (modifier - dot < sizeof (buf))
 437                 {
 438                   memcpy (buf, dot, modifier - dot);
 439                   buf [modifier - dot] = '\0';
 440                   return buf;
 441                 }
 442             }
 443         }
 444
 445       /* The Windows API has a function returning the locale's codepage as a
 446          number: GetACP().  This encoding is used by Cygwin, unless the user
 447          has set the environment variable CYGWIN=codepage:oem (which very few
 448          people do).
 449          Output directed to console windows needs to be converted (to
 450          GetOEMCP() if the console is using a raster font, or to
 451          GetConsoleOutputCP() if it is using a TrueType font).  Cygwin does
 452          this conversion transparently (see winsup/cygwin/fhandler_console.cc),
 453          converting to GetConsoleOutputCP().  This leads to correct results,
 454          except when SetConsoleOutputCP has been called and a raster font is
 455          in use.  */
 456       sprintf (buf, "CP%u", GetACP ());
 457       codeset = buf;
 458     }
 459 #  endif
 460
 461 # else
 462
 463   /* On old systems which lack it, use setlocale or getenv.  */
 464   const char *locale = NULL;
 465
 466   /* But most old systems don't have a complete set of locales.  Some
 467      (like SunOS 4 or DJGPP) have only the C locale.  Therefore we don't
 468      use setlocale here; it would return "C" when it doesn't support the
 469      locale name the user has set.  */
 470 #  if 0
 471   locale = setlocale (LC_CTYPE, NULL);
 472 #  endif
 473   if (locale == NULL || locale[0] == '\0')
 474     {
 475       locale = getenv ("LC_ALL");
 476       if (locale == NULL || locale[0] == '\0')
 477         {
 478           locale = getenv ("LC_CTYPE");
 479           if (locale == NULL || locale[0] == '\0')
 480             locale = getenv ("LANG");
 481         }
 482     }
 483
 484   /* On some old systems, one used to set locale = "iso8859_1". On others,
 485      you set it to "language_COUNTRY.charset". In any case, we resolve it
 486      through the charset.alias file.  */
 487   codeset = locale;
 488
 489 # endif
 490
 491 #elif defined WINDOWS_NATIVE
 492
 493   static char buf[2 + 10 + 1];
 494
 495   /* The Windows API has a function returning the locale's codepage as
 496      a number, but the value doesn't change according to what the
 497      'setlocale' call specified.  So we use it as a last resort, in
 498      case the string returned by 'setlocale' doesn't specify the
 499      codepage.  */
 500   char *current_locale = setlocale (LC_ALL, NULL);
 501   char *pdot;
 502
 503   /* If they set different locales for different categories,
 504      'setlocale' will return a semi-colon separated list of locale
 505      values.  To make sure we use the correct one, we choose LC_CTYPE.  */
 506   if (strchr (current_locale, ';'))
 507     current_locale = setlocale (LC_CTYPE, NULL);
 508
 509   pdot = strrchr (current_locale, '.');
 510   if (pdot)
 511     sprintf (buf, "CP%s", pdot + 1);
 512   else
 513     {
 514       /* The Windows API has a function returning the locale's codepage as a
 515         number: GetACP().
 516         When the output goes to a console window, it needs to be provided in
 517         GetOEMCP() encoding if the console is using a raster font, or in
 518         GetConsoleOutputCP() encoding if it is using a TrueType font.
 519         But in GUI programs and for output sent to files and pipes, GetACP()
 520         encoding is the best bet.  */
 521       sprintf (buf, "CP%u", GetACP ());
 522     }
 523   codeset = buf;
 524
 525 #elif defined OS2
 526
 527   const char *locale;
 528   static char buf[2 + 10 + 1];
 529   ULONG cp[3];
 530   ULONG cplen;
 531
 532   codeset = NULL;
 533
 534   /* Allow user to override the codeset, as set in the operating system,
 535      with standard language environment variables.  */
 536   locale = getenv ("LC_ALL");
 537   if (locale == NULL || locale[0] == '\0')
 538     {
 539       locale = getenv ("LC_CTYPE");
 540       if (locale == NULL || locale[0] == '\0')
 541         locale = getenv ("LANG");
 542     }
 543   if (locale != NULL && locale[0] != '\0')
 544     {
 545       /* If the locale name contains an encoding after the dot, return it.  */
 546       const char *dot = strchr (locale, '.');
 547
 548       if (dot != NULL)
 549         {
 550           const char *modifier;
 551
 552           dot++;
 553           /* Look for the possible @... trailer and remove it, if any.  */
 554           modifier = strchr (dot, '@');
 555           if (modifier == NULL)
 556             return dot;
 557           if (modifier - dot < sizeof (buf))
 558             {
 559               memcpy (buf, dot, modifier - dot);
 560               buf [modifier - dot] = '\0';
 561               return buf;
 562             }
 563         }
 564
 565       /* For the POSIX locale, don't use the system's codepage.  */
 566       if (strcmp (locale, "C") == 0 || strcmp (locale, "POSIX") == 0)
 567         codeset = "";
 568     }
 569
 570   if (codeset == NULL)
 571     {
 572       /* OS/2 has a function returning the locale's codepage as a number.  */
 573       if (DosQueryCp (sizeof (cp), cp, &cplen))
 574         codeset = "";
 575       else
 576         {
 577           sprintf (buf, "CP%u", cp[0]);
 578           codeset = buf;
 579         }
 580     }
 581
 582 #endif
 583
 584   if (codeset == NULL)
 585     /* The canonical name cannot be determined.  */
 586     codeset = "";
 587
 588   /* Resolve alias. */
 589   for (aliases = get_charset_aliases ();
 590        *aliases != '\0';
 591        aliases += strlen (aliases) + 1, aliases += strlen (aliases) + 1)
 592     if (strcmp (codeset, aliases) == 0
 593         || (aliases[0] == '*' && aliases[1] == '\0'))
 594       {
 595         codeset = aliases + strlen (aliases) + 1;
 596         break;
 597       }
 598
 599   /* Don't return an empty string.  GNU libc and GNU libiconv interpret
 600      the empty string as denoting "the locale's character encoding",
 601      thus GNU libiconv would call this function a second time.  */
 602   if (codeset[0] == '\0')
 603     codeset = "ASCII";
 604
 605 #ifdef DARWIN7
 606   /* Mac OS X sets MB_CUR_MAX to 1 when LC_ALL=C, and "UTF-8"
 607      (the default codeset) does not work when MB_CUR_MAX is 1.  */
 608   if (strcmp (codeset, "UTF-8") == 0 && MB_CUR_MAX_L (uselocale (NULL)) <= 1)
 609     codeset = "ASCII";
 610 #endif
 611
 612   return codeset;
 613 }