localcharset.c@ 3576

Last change on this file since 3576 was 2595, checked in by bird, 13 years ago
gnu grep version 2.12 (grep-2.12.tar.xz, md5sum=8d2f0346d08b13c18afb81f0e8aa1e2f)
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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 <[email protected]>. */
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. MacOS 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 *
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 *
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	return codeset;
546	}

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