1 /* Determine a canonical name for the current locale's character encoding.
2
3 Copyright (C) 2000-2006, 2008-2012 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 #endif
38
39 #if defined __EMX__
40 /* Assume EMX program runs on OS/2, even if compiled under DOS. */
41 # ifndef OS2
42 # define OS2
43 # endif
44 #endif
45
46 #if !defined WINDOWS_NATIVE
47 # include <unistd.h>
48 # if HAVE_LANGINFO_CODESET
49 # include <langinfo.h>
50 # else
51 # if 0 /* see comment below */
52 # include <locale.h>
53 # endif
54 # endif
55 # ifdef __CYGWIN__
56 # define WIN32_LEAN_AND_MEAN
57 # include <windows.h>
58 # endif
59 #elif defined WINDOWS_NATIVE
60 # define WIN32_LEAN_AND_MEAN
61 # include <windows.h>
62 #endif
63 #if defined OS2
64 # define INCL_DOS
65 # include <os2.h>
66 #endif
67
68 #if ENABLE_RELOCATABLE
69 # include "relocatable.h"
70 #else
71 # define relocate(pathname) (pathname)
72 #endif
73
74 /* Get LIBDIR. */
75 #ifndef LIBDIR
76 # include "configmake.h"
77 #endif
78
79 /* Define O_NOFOLLOW to 0 on platforms where it does not exist. */
80 #ifndef O_NOFOLLOW
81 # define O_NOFOLLOW 0
82 #endif
83
84 #if defined _WIN32 || defined __WIN32__ || defined __CYGWIN__ || defined __EMX__ || defined __DJGPP__
85 /* Native Windows, Cygwin, OS/2, DOS */
86 # define ISSLASH(C) ((C) == '/' || (C) == '\\')
87 #endif
88
89 #ifndef DIRECTORY_SEPARATOR
90 # define DIRECTORY_SEPARATOR '/'
91 #endif
92
93 #ifndef ISSLASH
94 # define ISSLASH(C) ((C) == DIRECTORY_SEPARATOR)
95 #endif
96
97 #if HAVE_DECL_GETC_UNLOCKED
98 # undef getc
99 # define getc getc_unlocked
100 #endif
101
102 /* The following static variable is declared 'volatile' to avoid a
103 possible multithread problem in the function get_charset_aliases. If we
104 are running in a threaded environment, and if two threads initialize
105 'charset_aliases' simultaneously, both will produce the same value,
106 and everything will be ok if the two assignments to 'charset_aliases'
107 are atomic. But I don't know what will happen if the two assignments mix. */
108 #if __STDC__ != 1
109 # define volatile /* empty */
110 #endif
111 /* Pointer to the contents of the charset.alias file, if it has already been
112 read, else NULL. Its format is:
113 ALIAS_1 '\0' CANONICAL_1 '\0' ... ALIAS_n '\0' CANONICAL_n '\0' '\0' */
114 static const char * volatile charset_aliases;
115
116 /* Return a pointer to the contents of the charset.alias file. */
117 static const char *
get_charset_aliases(void)118 get_charset_aliases (void)
119 {
120 const char *cp;
121
122 cp = charset_aliases;
123 if (cp == NULL)
124 {
125 #if !(defined DARWIN7 || defined VMS || defined WINDOWS_NATIVE || defined __CYGWIN__)
126 const char *dir;
127 const char *base = "charset.alias";
128 char *file_name;
129
130 /* Make it possible to override the charset.alias location. This is
131 necessary for running the testsuite before "make install". */
132 dir = getenv ("CHARSETALIASDIR");
133 if (dir == NULL || dir[0] == '\0')
134 dir = relocate (LIBDIR);
135
136 /* Concatenate dir and base into freshly allocated file_name. */
137 {
138 size_t dir_len = strlen (dir);
139 size_t base_len = strlen (base);
140 int add_slash = (dir_len > 0 && !ISSLASH (dir[dir_len - 1]));
141 file_name = (char *) malloc (dir_len + add_slash + base_len + 1);
142 if (file_name != NULL)
143 {
144 memcpy (file_name, dir, dir_len);
145 if (add_slash)
146 file_name[dir_len] = DIRECTORY_SEPARATOR;
147 memcpy (file_name + dir_len + add_slash, base, base_len + 1);
148 }
149 }
150
151 if (file_name == NULL)
152 /* Out of memory. Treat the file as empty. */
153 cp = "";
154 else
155 {
156 int fd;
157
158 /* Open the file. Reject symbolic links on platforms that support
159 O_NOFOLLOW. This is a security feature. Without it, an attacker
160 could retrieve parts of the contents (namely, the tail of the
161 first line that starts with "* ") of an arbitrary file by placing
162 a symbolic link to that file under the name "charset.alias" in
163 some writable directory and defining the environment variable
164 CHARSETALIASDIR to point to that directory. */
165 fd = open (file_name,
166 O_RDONLY | (HAVE_WORKING_O_NOFOLLOW ? O_NOFOLLOW : 0));
167 if (fd < 0)
168 /* File not found. Treat it as empty. */
169 cp = "";
170 else
171 {
172 FILE *fp;
173
174 fp = fdopen (fd, "r");
175 if (fp == NULL)
176 {
177 /* Out of memory. Treat the file as empty. */
178 close (fd);
179 cp = "";
180 }
181 else
182 {
183 /* Parse the file's contents. */
184 char *res_ptr = NULL;
185 size_t res_size = 0;
186
187 for (;;)
188 {
189 int c;
190 char buf1[50+1];
191 char buf2[50+1];
192 size_t l1, l2;
193 char *old_res_ptr;
194
195 c = getc (fp);
196 if (c == EOF)
197 break;
198 if (c == '\n' || c == ' ' || c == '\t')
199 continue;
200 if (c == '#')
201 {
202 /* Skip comment, to end of line. */
203 do
204 c = getc (fp);
205 while (!(c == EOF || c == '\n'));
206 if (c == EOF)
207 break;
208 continue;
209 }
210 ungetc (c, fp);
211 if (fscanf (fp, "%50s %50s", buf1, buf2) < 2)
212 break;
213 l1 = strlen (buf1);
214 l2 = strlen (buf2);
215 old_res_ptr = res_ptr;
216 if (res_size == 0)
217 {
218 res_size = l1 + 1 + l2 + 1;
219 res_ptr = (char *) malloc (res_size + 1);
220 }
221 else
222 {
223 res_size += l1 + 1 + l2 + 1;
224 res_ptr = (char *) realloc (res_ptr, res_size + 1);
225 }
226 if (res_ptr == NULL)
227 {
228 /* Out of memory. */
229 res_size = 0;
230 free (old_res_ptr);
231 break;
232 }
233 strcpy (res_ptr + res_size - (l2 + 1) - (l1 + 1), buf1);
234 strcpy (res_ptr + res_size - (l2 + 1), buf2);
235 }
236 fclose (fp);
237 if (res_size == 0)
238 cp = "";
239 else
240 {
241 *(res_ptr + res_size) = '\0';
242 cp = res_ptr;
243 }
244 }
245 }
246
247 free (file_name);
248 }
249
250 #else
251
252 # if defined DARWIN7
253 /* To avoid the trouble of installing a file that is shared by many
254 GNU packages -- many packaging systems have problems with this --,
255 simply inline the aliases here. */
256 cp = "ISO8859-1" "\0" "ISO-8859-1" "\0"
257 "ISO8859-2" "\0" "ISO-8859-2" "\0"
258 "ISO8859-4" "\0" "ISO-8859-4" "\0"
259 "ISO8859-5" "\0" "ISO-8859-5" "\0"
260 "ISO8859-7" "\0" "ISO-8859-7" "\0"
261 "ISO8859-9" "\0" "ISO-8859-9" "\0"
262 "ISO8859-13" "\0" "ISO-8859-13" "\0"
263 "ISO8859-15" "\0" "ISO-8859-15" "\0"
264 "KOI8-R" "\0" "KOI8-R" "\0"
265 "KOI8-U" "\0" "KOI8-U" "\0"
266 "CP866" "\0" "CP866" "\0"
267 "CP949" "\0" "CP949" "\0"
268 "CP1131" "\0" "CP1131" "\0"
269 "CP1251" "\0" "CP1251" "\0"
270 "eucCN" "\0" "GB2312" "\0"
271 "GB2312" "\0" "GB2312" "\0"
272 "eucJP" "\0" "EUC-JP" "\0"
273 "eucKR" "\0" "EUC-KR" "\0"
274 "Big5" "\0" "BIG5" "\0"
275 "Big5HKSCS" "\0" "BIG5-HKSCS" "\0"
276 "GBK" "\0" "GBK" "\0"
277 "GB18030" "\0" "GB18030" "\0"
278 "SJIS" "\0" "SHIFT_JIS" "\0"
279 "ARMSCII-8" "\0" "ARMSCII-8" "\0"
280 "PT154" "\0" "PT154" "\0"
281 /*"ISCII-DEV" "\0" "?" "\0"*/
282 "*" "\0" "UTF-8" "\0";
283 # endif
284
285 # if defined VMS
286 /* To avoid the troubles of an extra file charset.alias_vms in the
287 sources of many GNU packages, simply inline the aliases here. */
288 /* The list of encodings is taken from the OpenVMS 7.3-1 documentation
289 "Compaq C Run-Time Library Reference Manual for OpenVMS systems"
290 section 10.7 "Handling Different Character Sets". */
291 cp = "ISO8859-1" "\0" "ISO-8859-1" "\0"
292 "ISO8859-2" "\0" "ISO-8859-2" "\0"
293 "ISO8859-5" "\0" "ISO-8859-5" "\0"
294 "ISO8859-7" "\0" "ISO-8859-7" "\0"
295 "ISO8859-8" "\0" "ISO-8859-8" "\0"
296 "ISO8859-9" "\0" "ISO-8859-9" "\0"
297 /* Japanese */
298 "eucJP" "\0" "EUC-JP" "\0"
299 "SJIS" "\0" "SHIFT_JIS" "\0"
300 "DECKANJI" "\0" "DEC-KANJI" "\0"
301 "SDECKANJI" "\0" "EUC-JP" "\0"
302 /* Chinese */
303 "eucTW" "\0" "EUC-TW" "\0"
304 "DECHANYU" "\0" "DEC-HANYU" "\0"
305 "DECHANZI" "\0" "GB2312" "\0"
306 /* Korean */
307 "DECKOREAN" "\0" "EUC-KR" "\0";
308 # endif
309
310 # if defined WINDOWS_NATIVE || defined __CYGWIN__
311 /* To avoid the troubles of installing a separate file in the same
312 directory as the DLL and of retrieving the DLL's directory at
313 runtime, simply inline the aliases here. */
314
315 cp = "CP936" "\0" "GBK" "\0"
316 "CP1361" "\0" "JOHAB" "\0"
317 "CP20127" "\0" "ASCII" "\0"
318 "CP20866" "\0" "KOI8-R" "\0"
319 "CP20936" "\0" "GB2312" "\0"
320 "CP21866" "\0" "KOI8-RU" "\0"
321 "CP28591" "\0" "ISO-8859-1" "\0"
322 "CP28592" "\0" "ISO-8859-2" "\0"
323 "CP28593" "\0" "ISO-8859-3" "\0"
324 "CP28594" "\0" "ISO-8859-4" "\0"
325 "CP28595" "\0" "ISO-8859-5" "\0"
326 "CP28596" "\0" "ISO-8859-6" "\0"
327 "CP28597" "\0" "ISO-8859-7" "\0"
328 "CP28598" "\0" "ISO-8859-8" "\0"
329 "CP28599" "\0" "ISO-8859-9" "\0"
330 "CP28605" "\0" "ISO-8859-15" "\0"
331 "CP38598" "\0" "ISO-8859-8" "\0"
332 "CP51932" "\0" "EUC-JP" "\0"
333 "CP51936" "\0" "GB2312" "\0"
334 "CP51949" "\0" "EUC-KR" "\0"
335 "CP51950" "\0" "EUC-TW" "\0"
336 "CP54936" "\0" "GB18030" "\0"
337 "CP65001" "\0" "UTF-8" "\0";
338 # endif
339 #endif
340
341 charset_aliases = cp;
342 }
343
344 return cp;
345 }
346
347 /* Determine the current locale's character encoding, and canonicalize it
348 into one of the canonical names listed in config.charset.
349 The result must not be freed; it is statically allocated.
350 If the canonical name cannot be determined, the result is a non-canonical
351 name. */
352
353 #ifdef STATIC
354 STATIC
355 #endif
356 const char *
locale_charset(void)357 locale_charset (void)
358 {
359 const char *codeset;
360 const char *aliases;
361
362 #if !(defined WINDOWS_NATIVE || defined OS2)
363
364 # if HAVE_LANGINFO_CODESET
365
366 /* Most systems support nl_langinfo (CODESET) nowadays. */
367 codeset = nl_langinfo (CODESET);
368
369 # ifdef __CYGWIN__
370 /* Cygwin < 1.7 does not have locales. nl_langinfo (CODESET) always
371 returns "US-ASCII". Return the suffix of the locale name from the
372 environment variables (if present) or the codepage as a number. */
373 if (codeset != NULL && strcmp (codeset, "US-ASCII") == 0)
374 {
375 const char *locale;
376 static char buf[2 + 10 + 1];
377
378 locale = getenv ("LC_ALL");
379 if (locale == NULL || locale[0] == '\0')
380 {
381 locale = getenv ("LC_CTYPE");
382 if (locale == NULL || locale[0] == '\0')
383 locale = getenv ("LANG");
384 }
385 if (locale != NULL && locale[0] != '\0')
386 {
387 /* If the locale name contains an encoding after the dot, return
388 it. */
389 const char *dot = strchr (locale, '.');
390
391 if (dot != NULL)
392 {
393 const char *modifier;
394
395 dot++;
396 /* Look for the possible @... trailer and remove it, if any. */
397 modifier = strchr (dot, '@');
398 if (modifier == NULL)
399 return dot;
400 if (modifier - dot < sizeof (buf))
401 {
402 memcpy (buf, dot, modifier - dot);
403 buf [modifier - dot] = '\0';
404 return buf;
405 }
406 }
407 }
408
409 /* The Windows API has a function returning the locale's codepage as a
410 number: GetACP(). This encoding is used by Cygwin, unless the user
411 has set the environment variable CYGWIN=codepage:oem (which very few
412 people do).
413 Output directed to console windows needs to be converted (to
414 GetOEMCP() if the console is using a raster font, or to
415 GetConsoleOutputCP() if it is using a TrueType font). Cygwin does
416 this conversion transparently (see winsup/cygwin/fhandler_console.cc),
417 converting to GetConsoleOutputCP(). This leads to correct results,
418 except when SetConsoleOutputCP has been called and a raster font is
419 in use. */
420 sprintf (buf, "CP%u", GetACP ());
421 codeset = buf;
422 }
423 # endif
424
425 # else
426
427 /* On old systems which lack it, use setlocale or getenv. */
428 const char *locale = NULL;
429
430 /* But most old systems don't have a complete set of locales. Some
431 (like SunOS 4 or DJGPP) have only the C locale. Therefore we don't
432 use setlocale here; it would return "C" when it doesn't support the
433 locale name the user has set. */
434 # if 0
435 locale = setlocale (LC_CTYPE, NULL);
436 # endif
437 if (locale == NULL || locale[0] == '\0')
438 {
439 locale = getenv ("LC_ALL");
440 if (locale == NULL || locale[0] == '\0')
441 {
442 locale = getenv ("LC_CTYPE");
443 if (locale == NULL || locale[0] == '\0')
444 locale = getenv ("LANG");
445 }
446 }
447
448 /* On some old systems, one used to set locale = "iso8859_1". On others,
449 you set it to "language_COUNTRY.charset". In any case, we resolve it
450 through the charset.alias file. */
451 codeset = locale;
452
453 # endif
454
455 #elif defined WINDOWS_NATIVE
456
457 static char buf[2 + 10 + 1];
458
459 /* The Windows API has a function returning the locale's codepage as a
460 number: GetACP().
461 When the output goes to a console window, it needs to be provided in
462 GetOEMCP() encoding if the console is using a raster font, or in
463 GetConsoleOutputCP() encoding if it is using a TrueType font.
464 But in GUI programs and for output sent to files and pipes, GetACP()
465 encoding is the best bet. */
466 sprintf (buf, "CP%u", GetACP ());
467 codeset = buf;
468
469 #elif defined OS2
470
471 const char *locale;
472 static char buf[2 + 10 + 1];
473 ULONG cp[3];
474 ULONG cplen;
475
476 /* Allow user to override the codeset, as set in the operating system,
477 with standard language environment variables. */
478 locale = getenv ("LC_ALL");
479 if (locale == NULL || locale[0] == '\0')
480 {
481 locale = getenv ("LC_CTYPE");
482 if (locale == NULL || locale[0] == '\0')
483 locale = getenv ("LANG");
484 }
485 if (locale != NULL && locale[0] != '\0')
486 {
487 /* If the locale name contains an encoding after the dot, return it. */
488 const char *dot = strchr (locale, '.');
489
490 if (dot != NULL)
491 {
492 const char *modifier;
493
494 dot++;
495 /* Look for the possible @... trailer and remove it, if any. */
496 modifier = strchr (dot, '@');
497 if (modifier == NULL)
498 return dot;
499 if (modifier - dot < sizeof (buf))
500 {
501 memcpy (buf, dot, modifier - dot);
502 buf [modifier - dot] = '\0';
503 return buf;
504 }
505 }
506
507 /* Resolve through the charset.alias file. */
508 codeset = locale;
509 }
510 else
511 {
512 /* OS/2 has a function returning the locale's codepage as a number. */
513 if (DosQueryCp (sizeof (cp), cp, &cplen))
514 codeset = "";
515 else
516 {
517 sprintf (buf, "CP%u", cp[0]);
518 codeset = buf;
519 }
520 }
521
522 #endif
523
524 if (codeset == NULL)
525 /* The canonical name cannot be determined. */
526 codeset = "";
527
528 /* Resolve alias. */
529 for (aliases = get_charset_aliases ();
530 *aliases != '\0';
531 aliases += strlen (aliases) + 1, aliases += strlen (aliases) + 1)
532 if (strcmp (codeset, aliases) == 0
533 || (aliases[0] == '*' && aliases[1] == '\0'))
534 {
535 codeset = aliases + strlen (aliases) + 1;
536 break;
537 }
538
539 /* Don't return an empty string. GNU libc and GNU libiconv interpret
540 the empty string as denoting "the locale's character encoding",
541 thus GNU libiconv would call this function a second time. */
542 if (codeset[0] == '\0')
543 codeset = "ASCII";
544
545 #ifdef DARWIN7
546 /* Mac OS X sets MB_CUR_MAX to 1 when LC_ALL=C, and "UTF-8"
547 (the default codeset) does not work when MB_CUR_MAX is 1. */
548 if (strcmp (codeset, "UTF-8") == 0 && MB_CUR_MAX <= 1)
549 codeset = "ASCII";
550 #endif
551
552 return codeset;
553 }
554