source: vendor/3.6.23/docs-xml/Samba3-HOWTO/TOSHARG-Unicode.xml

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1<?xml version="1.0" encoding="iso-8859-1"?>
2<!DOCTYPE chapter PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
3<chapter id="unicode">
4<chapterinfo>
5 &author.jelmer;
6 &author.jht;
7 <author>
8 <firstname>TAKAHASHI</firstname><surname>Motonobu</surname>
9 <affiliation>
10 <address><email>monyo@home.monyo.com</email></address>
11 </affiliation>
12 <contrib>Japanese character support</contrib>
13 </author>
14 <pubdate>25 March 2003</pubdate>
15</chapterinfo>
16
17<title>Unicode/Charsets</title>
18
19<sect1>
20<title>Features and Benefits</title>
21
22<para>
23<indexterm><primary>use computer anywhere</primary></indexterm>
24Every industry eventually matures. One of the great areas of maturation is in
25the focus that has been given over the past decade to make it possible for anyone
26anywhere to use a computer. It has not always been that way. In fact, not so long
27ago, it was common for software to be written for exclusive use in the country of
28origin.
29</para>
30
31<para>
32Of all the effort that has been brought to bear on providing native
33language support for all computer users, the efforts of the
34<ulink url="http://www.openi18n.org/">Openi18n organization</ulink>
35is deserving of special mention.
36</para>
37
38<para>
39<indexterm><primary>codepages</primary></indexterm>
40Samba-2.x supported a single locale through a mechanism called
41<emphasis>codepages</emphasis>. Samba-3 is destined to become a truly transglobal
42file- and printer-sharing platform.
43</para>
44
45</sect1>
46
47<sect1>
48<title>What Are Charsets and Unicode?</title>
49
50<para>
51<indexterm><primary>character set</primary></indexterm>
52Computers communicate in numbers. In texts, each number is
53translated to a corresponding letter. The meaning that will be assigned
54to a certain number depends on the <emphasis>character set (charset)
55</emphasis> that is used.
56</para>
57
58<para>
59<indexterm><primary>charset</primary></indexterm>
60<indexterm><primary>ASCII</primary></indexterm>
61A charset can be seen as a table that is used to translate numbers to
62letters. Not all computers use the same charset (there are charsets
63with German umlauts, Japanese characters, and so on). The American Standard Code
64for Information Interchange (ASCII) encoding system has been the normative character
65encoding scheme used by computers to date. This employs a charset that contains
66256 characters. Using this mode of encoding, each character takes exactly one byte.
67</para>
68
69<para>
70<indexterm><primary>multibyte charsets</primary></indexterm>
71<indexterm><primary>extended characters</primary></indexterm>
72There are also charsets that support extended characters, but those need at least
73twice as much storage space as does ASCII encoding. Such charsets can contain
74<command>256 * 256 = 65536</command> characters, which is more than all possible
75characters one could think of. They are called multibyte charsets because they use
76more then one byte to store one character.
77</para>
78
79<para>
80<indexterm><primary>unicode</primary></indexterm>
81One standardized multibyte charset encoding scheme is known as
82<ulink url="http://www.unicode.org/">unicode</ulink>. A big advantage of using a
83multibyte charset is that you only need one. There is no need to make sure two
84computers use the same charset when they are communicating.
85</para>
86
87<para>
88<indexterm><primary>single-byte charsets</primary></indexterm>
89<indexterm><primary>SMB/CIFS</primary></indexterm>
90<indexterm><primary>negotiating the charset</primary></indexterm>
91Old Windows clients use single-byte charsets, named
92<parameter>codepages</parameter>, by Microsoft. However, there is no support for
93negotiating the charset to be used in the SMB/CIFS protocol. Thus, you
94have to make sure you are using the same charset when talking to an older client.
95Newer clients (Windows NT, 200x, XP) talk Unicode over the wire.
96</para>
97</sect1>
98
99<sect1>
100<title>Samba and Charsets</title>
101
102<para>
103<indexterm><primary>Unicode</primary></indexterm>
104<indexterm><primary>character sets</primary></indexterm>
105As of Samba-3, Samba can (and will) talk Unicode over the wire. Internally,
106Samba knows of three kinds of character sets:
107</para>
108
109<variablelist>
110 <varlistentry>
111 <term><smbconfoption name="unix charset"/></term>
112 <listitem><para>
113<indexterm><primary>UTF-8</primary></indexterm>
114<indexterm><primary>CP850</primary></indexterm>
115 This is the charset used internally by your operating system.
116 The default is <constant>UTF-8</constant>, which is fine for most
117 systems and covers all characters in all languages. The default
118 in previous Samba releases was to save filenames in the encoding of the
119 clients &smbmdash; for example, CP850 for Western European countries.
120 </para></listitem>
121 </varlistentry>
122
123 <varlistentry>
124 <term><smbconfoption name="display charset"/></term>
125 <listitem><para>This is the charset Samba uses to print messages
126 on your screen. It should generally be the same as the <parameter>unix charset</parameter>.
127 </para></listitem>
128 </varlistentry>
129
130 <varlistentry>
131 <term><smbconfoption name="dos charset"/></term>
132 <listitem><para>This is the charset Samba uses when communicating with
133 DOS and Windows 9x/Me clients. It will talk Unicode to all newer clients.
134 The default depends on the charsets you have installed on your system.
135 Run <command>testparm -v | grep &quot;dos charset&quot;</command> to see
136 what the default is on your system.
137 </para></listitem>
138 </varlistentry>
139</variablelist>
140
141</sect1>
142
143<sect1>
144<title>Conversion from Old Names</title>
145
146<para>
147<indexterm><primary>charset conversion</primary></indexterm>
148Because previous Samba versions did not do any charset conversion,
149characters in filenames are usually not correct in the UNIX charset but only
150for the local charset used by the DOS/Windows clients.
151</para>
152
153<para>Bjoern Jacke has written a utility named <ulink url="http://j3e.de/linux/convmv/">convmv</ulink>
154that can convert whole directory structures to different charsets with one single command.
155</para>
156
157</sect1>
158
159<sect1>
160<title>Japanese Charsets</title>
161
162<para>
163Setting up Japanese charsets is quite difficult. This is mainly because:
164</para>
165
166<itemizedlist>
167 <listitem><para>
168<indexterm><primary>JIS X 0208</primary></indexterm>
169 The Windows character set is extended from the original legacy Japanese
170 standard (JIS X 0208) and is not standardized. This means that the strictly
171 standardized implementation cannot support the full Windows character set.
172 </para></listitem>
173
174 <listitem><para>
175<indexterm><primary>Shift_JIS</primary></indexterm>
176<indexterm><primary>EUC-JP</primary></indexterm>
177<indexterm><primary>CAP</primary></indexterm>
178<indexterm><primary>HEX</primary></indexterm>
179<indexterm><primary>Japanese</primary></indexterm>
180 Mainly for historical reasons, there are several encoding methods in
181 Japanese, which are not fully compatible with each other. There are
182 two major encoding methods. One is the Shift_JIS series used in Windows
183 and some UNIXes. The other is the EUC-JP series used in most UNIXes
184 and Linux. Moreover, Samba previously also offered several unique encoding
185 methods, named CAP and HEX, to keep interoperability with CAP/NetAtalk and
186 UNIXes that can't use Japanese filenames. Some implementations of the
187 EUC-JP series can't support the full Windows character set.
188 </para></listitem>
189
190 <listitem><para>There are some code conversion tables between Unicode and legacy
191 Japanese character sets. One is compatible with Windows, another one
192 is based on the reference of the Unicode consortium, and others are
193 a mixed implementation. The Unicode consortium does not officially
194 define any conversion tables between Unicode and legacy character
195 sets, so there cannot be standard one.
196 </para></listitem>
197
198 <listitem><para>The character set and conversion tables available in iconv() depend
199 on the iconv library that is available. Next to that, the Japanese locale
200 names may be different on different systems. This means that the value of
201 the charset parameters depends on the implementation of iconv() you are using.
202 </para>
203
204 <para>
205<indexterm><primary>UCS-2</primary></indexterm>
206<indexterm><primary>Shift_JIS</primary></indexterm>
207<indexterm><primary>ASCII</primary></indexterm>
208<indexterm><primary>English</primary></indexterm>
209 Though 2-byte fixed UCS-2 encoding is used in Windows internally,
210 Shift_JIS series encoding is usually used in Japanese environments
211 as ASCII encoding is in English environments.
212 </para></listitem>
213</itemizedlist>
214
215<sect2><title>Basic Parameter Setting</title>
216
217 <para>
218<indexterm><primary>CP932</primary></indexterm>
219 The <smbconfoption name="dos charset"/> and
220 <smbconfoption name="display charset"/>
221 should be set to the locale compatible with the character set
222 and encoding method used on Windows. This is usually CP932
223 but sometimes has a different name.
224 </para>
225
226 <para>
227<indexterm><primary>Shift_JIS</primary></indexterm>
228<indexterm><primary>UTF-8</primary></indexterm>
229<indexterm><primary>EUC-JP</primary></indexterm>
230 The <smbconfoption name="unix charset"/> can be either Shift_JIS series,
231 EUC-JP series, or UTF-8. UTF-8 is always available, but the availability of other locales
232 and the name itself depends on the system.
233 </para>
234
235 <para>
236 Additionally, you can consider using the Shift_JIS series as the
237 value of the <smbconfoption name="unix charset"/>
238 parameter by using the vfs_cap module, which does the same thing as
239 setting <quote>coding system = CAP</quote> in the Samba 2.2 series.
240 </para>
241
242 <para>
243 Where to set <smbconfoption name="unix charset"/>
244 to is a difficult question. Here is a list of details, advantages, and
245 disadvantages of using a certain value.
246 </para>
247
248 <variablelist>
249 <varlistentry><term>Shift_JIS series</term>
250 <listitem><para>
251 Shift_JIS series means a locale that is equivalent to <constant>Shift_JIS</constant>,
252 used as a standard on Japanese Windows. In the case of <constant>Shift_JIS</constant>,
253 for example, if a Japanese filename consists of 0x8ba4 and 0x974c
254 (a 4-bytes Japanese character string meaning <quote>share</quote>) and <quote>.txt</quote>
255 is written from Windows on Samba, the filename on UNIX becomes
256 0x8ba4, 0x974c, <quote>.txt</quote> (an 8-byte BINARY string), same as Windows.
257 </para>
258
259 <para>Since Shift_JIS series is usually used on some commercial-based
260 UNIXes; hp-ux and AIX as the Japanese locale (however, it is also possible
261 to use the EUC-JP locale series). To use Shift_JIS series on these platforms,
262 Japanese filenames created from Windows can be referred to also on
263 UNIX.</para>
264
265 <para>
266 If your UNIX is already working with Shift_JIS and there is a user
267 who needs to use Japanese filenames written from Windows, the
268 Shift_JIS series is the best choice. However, broken filenames
269 may be displayed, and some commands that cannot handle non-ASCII
270 filenames may be aborted during parsing filenames. Especially, there
271 may be <quote>\ (0x5c)</quote> in filenames, which need to be handled carefully.
272 It is best to not touch filenames written from Windows on UNIX.
273 </para>
274
275 <para>
276 Note that most Japanized free software actually works with EUC-JP
277 only. It is good practice to verify that the Japanized free software can work
278 with Shift_JIS.
279 </para>
280 </listitem>
281 </varlistentry>
282
283 <varlistentry><term>EUC-JP series</term>
284 <listitem><para>
285<indexterm><primary>EUC-JP</primary></indexterm>
286<indexterm><primary>Japanese UNIX</primary></indexterm>
287 EUC-JP series means a locale that is equivalent to the industry
288 standard called EUC-JP, widely used in Japanese UNIX (although EUC
289 contains specifications for languages other than Japanese, such as
290 EUC-KR). In the case of EUC-JP series, for example, if a Japanese
291 filename consists of 0x8ba4 and 0x974c and <quote>.txt</quote> is written from
292 Windows on Samba, the filename on UNIX becomes 0xb6a6, 0xcdad,
293 <quote>.txt</quote> (an 8-byte BINARY string).
294 </para>
295
296 <para>
297<indexterm><primary>EUC-JP</primary></indexterm>
298<indexterm><primary>UNIX</primary></indexterm>
299<indexterm><primary>Linux</primary></indexterm>
300<indexterm><primary>FreeBSD</primary></indexterm>
301<indexterm><primary>Solaris</primary></indexterm>
302<indexterm><primary>IRIX</primary></indexterm>
303<indexterm><primary>Tru64 UNIX</primary></indexterm>
304<indexterm><primary>Japanese locale</primary></indexterm>
305<indexterm><primary>Shift_JIS</primary></indexterm>
306<indexterm><primary>UTF-8</primary></indexterm>
307 Since EUC-JP is usually used on open source UNIX, Linux, and FreeBSD, and on commercial-based UNIX, Solaris,
308 IRIX, and Tru64 UNIX as Japanese locale (however, it is also possible on Solaris to use Shift_JIS and UTF-8,
309 and on Tru64 UNIX it is possible to use Shift_JIS). To use EUC-JP series, most Japanese filenames created from
310 Windows can be referred to also on UNIX. Also, most Japanized free software works mainly with EUC-JP only.
311 </para>
312
313 <para>
314 It is recommended to choose EUC-JP series when using Japanese filenames on UNIX.
315 </para>
316
317 <para>
318 Although there is no character that needs to be carefully treated
319 like <quote>\ (0x5c)</quote>, broken filenames may be displayed and some
320 commands that cannot handle non-ASCII filenames may be aborted
321 during parsing filenames.
322 </para>
323
324 <para>
325<indexterm><primary>eucJP-ms locale</primary></indexterm>
326 Moreover, if you built Samba using differently installed libiconv,
327 the eucJP-ms locale included in libiconv and EUC-JP series locale
328 included in the operating system may not be compatible. In this case, you may need to
329 avoid using incompatible characters for filenames.
330 </para>
331 </listitem>
332 </varlistentry>
333
334 <varlistentry><term>UTF-8</term>
335 <listitem><para>
336 UTF-8 means a locale equivalent to UTF-8, the international standard defined by the Unicode consortium. In
337 UTF-8, a <parameter>character</parameter> is expressed using 1 to 3 bytes. In case of the Japanese language,
338 most characters are expressed using 3 bytes. Since on Windows Shift_JIS, where a character is expressed with 1
339 or 2 bytes is used to express Japanese, basically a byte length of a UTF-8 string the length of the UTF-8
340 string is 1.5 times that of the original Shift_JIS string. In the case of UTF-8, for example, if a Japanese
341 filename consists of 0x8ba4 and 0x974c, and <quote>.txt</quote> is written from Windows on Samba, the filename
342 on UNIX becomes 0xe585, 0xb1e6, 0x9c89, <quote>.txt</quote> (a 10-byte BINARY string).
343 </para>
344
345 <para>
346 For systems where iconv() is not available or where iconv()'s locales
347 are not compatible with Windows, UTF-8 is the only locale available.
348 </para>
349
350 <para>
351 There are no systems that use UTF-8 as the default locale for Japanese.
352 </para>
353
354 <para>
355 Some broken filenames may be displayed, and some commands that
356 cannot handle non-ASCII filenames may be aborted during parsing
357 filenames. Especially, there may be <quote>\ (0x5c)</quote> in filenames, which
358 must be handled carefully, so you had better not touch filenames
359 written from Windows on UNIX.
360 </para>
361
362 <para>
363<indexterm><primary>Windows</primary></indexterm>
364<indexterm><primary>Java</primary></indexterm>
365<indexterm><primary>Unicode UTF-8</primary></indexterm>
366 In addition, although it is not directly concerned with Samba, since
367 there is a delicate difference between the iconv() function, which is
368 generally used on UNIX, and the functions used on other platforms,
369 such as Windows and Java, so far is concerns the conversion between
370 Shift_JIS and Unicode UTF-8 must be done with care and recognition
371 of the limitations involved in the process.
372 </para>
373
374 <para>
375<indexterm><primary>Mac OS X </primary></indexterm>
376 Although Mac OS X uses UTF-8 as its encoding method for filenames,
377 it uses an extended UTF-8 specification that Samba cannot handle, so
378 UTF-8 locale is not available for Mac OS X.
379 </para>
380 </listitem>
381 </varlistentry>
382
383 <varlistentry><term>Shift_JIS series + vfs_cap (CAP encoding)</term>
384 <listitem><para>
385<indexterm><primary>CAP</primary></indexterm>
386<indexterm><primary>NetAtalk</primary></indexterm>
387<indexterm><primary>Macintosh</primary></indexterm>
388 CAP encoding means a specification used in CAP and NetAtalk, file
389 server software for Macintosh. In the case of CAP encoding, for
390 example, if a Japanese filename consists of 0x8ba4 and 0x974c, and
391 <quote>.txt</quote> is written from Windows on Samba, the filename on UNIX
392 becomes <quote>:8b:a4:97L.txt</quote> (a 14 bytes ASCII string).
393 </para>
394
395 <para>
396 For CAP encoding, a byte that cannot be expressed as an ASCII
397 character (0x80 or above) is encoded in an <quote>:xx</quote> form. You need to take
398 care of containing a <quote>\(0x5c)</quote> in a filename, but filenames are not
399 broken in a system that cannot handle non-ASCII filenames.
400 </para>
401
402 <para>
403 The greatest merit of CAP encoding is the compatibility of encoding
404 filenames with CAP or NetAtalk. These are respectively the Columbia Appletalk
405 Protocol, and the NetAtalk Open Source software project.
406 Since these software applications write a file name on UNIX with CAP encoding, if a
407 directory is shared with both Samba and NetAtalk, you need to use
408 CAP encoding to avoid non-ASCII filenames from being broken.
409 </para>
410
411 <para>
412 However, recently, NetAtalk has been
413 patched on some systems to write filenames with EUC-JP (e.g., Japanese original Vine Linux).
414 In this case, you need to choose EUC-JP series instead of CAP encoding.
415 </para>
416
417 <para>
418 vfs_cap itself is available for non-Shift_JIS series locales for
419 systems that cannot handle non-ASCII characters or systems that
420 share files with NetAtalk.
421 </para>
422
423 <para>
424 To use CAP encoding on Samba-3, you should use the unix charset parameter and VFS
425 as in <link linkend="vfscap-intl">the VFS CAP smb.conf file</link>.
426 </para>
427
428<example id="vfscap-intl">
429<title>VFS CAP</title>
430 <smbconfblock>
431<smbconfsection name="[global]"/>
432<smbconfcomment>the locale name "CP932" may be different</smbconfcomment>
433<smbconfoption name="dos charset">CP932</smbconfoption>
434<smbconfoption name="unix charset">CP932</smbconfoption>
435
436<smbconfsection name="[cap-share]"/>
437<smbconfoption name="vfs option">cap</smbconfoption>
438</smbconfblock>
439</example>
440
441 <para>
442<indexterm><primary>CP932</primary></indexterm>
443<indexterm><primary>libiconv</primary></indexterm>
444<indexterm><primary>unix charset</primary></indexterm>
445<indexterm><primary>cap-share</primary></indexterm>
446 You should set CP932 if using GNU libiconv for unix charset. With this setting,
447 filenames in the <quote>cap-share</quote> share are written with CAP encoding.
448 </para>
449 </listitem>
450 </varlistentry>
451 </variablelist>
452
453</sect2>
454
455<sect2><title>Individual Implementations</title>
456
457<para>
458Here is some additional information regarding individual implementations:
459</para>
460
461 <variablelist>
462 <varlistentry><term>GNU libiconv</term>
463 <listitem><para>
464 To handle Japanese correctly, you should apply the patch
465 <ulink url="http://www2d.biglobe.ne.jp/~msyk/software/libiconv-patch.html">libiconv-1.8-cp932-patch.diff.gz</ulink>
466 to libiconv-1.8.
467 </para>
468
469 <para>
470 Using the patched libiconv-1.8, these settings are available:
471 </para>
472
473<programlisting>
474dos charset = CP932
475unix charset = CP932 / eucJP-ms / UTF-8
476 | |
477 | +-- EUC-JP series
478 +-- Shift_JIS series
479display charset = CP932
480</programlisting>
481
482 <para>
483 Other Japanese locales (for example, Shift_JIS and EUC-JP) should not
484 be used because of the lack of the compatibility with Windows.
485 </para>
486 </listitem>
487 </varlistentry>
488
489 <varlistentry><term>GNU glibc</term>
490 <listitem><para>
491 To handle Japanese correctly, you should apply a <ulink url="http://www2d.biglobe.ne.jp/~msyk/software/glibc/">patch</ulink>
492 to glibc-2.2.5/2.3.1/2.3.2 or should use the patch-merged versions, glibc-2.3.3 or later.
493 </para>
494
495 <para>
496 Using the above glibc, these setting are available:
497 <smbconfblock>
498 <smbconfoption name="dos charset">CP932</smbconfoption>
499 <smbconfoption name="unix charset">CP932 / eucJP-ms / UTF-8</smbconfoption>
500 <smbconfoption name="display charset">CP932</smbconfoption>
501 </smbconfblock>
502 </para>
503
504 <para>
505 Other Japanese locales (for example, Shift_JIS and EUC-JP) should not
506 be used because of the lack of the compatibility with Windows.
507 </para>
508 </listitem>
509 </varlistentry>
510 </variablelist>
511
512</sect2>
513
514<sect2>
515 <title>Migration from Samba-2.2 Series</title>
516
517<para>
518Prior to Samba-2.2 series, the <quote>coding system</quote> parameter was used. The default codepage in Samba
5192.x was code page 850. In the Samba-3 series this has been replaced with the <smbconfoption name="unix
520charset"/> parameter. <link linkend="japancharsets">Japanese Character Sets in Samba-2.2 and Samba-3</link>
521shows the mapping table when migrating from the Samba-2.2 series to Samba-3.
522</para>
523
524 <table frame="all" id="japancharsets">
525 <title>Japanese Character Sets in Samba-2.2 and Samba-3</title>
526
527 <tgroup cols="2" align="center">
528 <colspec align="center"/>
529 <colspec align="center"/>
530 <thead>
531 <row><entry>Samba-2.2 Coding System</entry><entry>Samba-3 unix charset</entry></row>
532 </thead>
533 <tbody>
534 <row><entry>SJIS</entry><entry>Shift_JIS series</entry></row>
535 <row><entry>EUC</entry><entry>EUC-JP series</entry></row>
536 <row><entry>EUC3<footnote><para>Only exists in Japanese Samba version</para></footnote></entry><entry>EUC-JP series</entry></row>
537 <row><entry>CAP</entry><entry>Shift_JIS series + VFS</entry></row>
538 <row><entry>HEX</entry><entry>currently none</entry></row>
539 <row><entry>UTF8</entry><entry>UTF-8</entry></row>
540 <row><entry>UTF8-Mac<footnote><para>Only exists in Japanese Samba version</para></footnote></entry><entry>currently none</entry></row>
541 <row><entry>others</entry><entry>none</entry></row>
542 </tbody>
543 </tgroup>
544 </table>
545
546</sect2>
547
548</sect1>
549
550<sect1>
551 <title>Common Errors</title>
552
553 <sect2>
554 <title>CP850.so Can't Be Found</title>
555
556 <para><quote>Samba is complaining about a missing <filename>CP850.so</filename> file.</quote></para>
557
558 <para>
559 CP850 is the default <smbconfoption name="dos charset"/>.
560 The <smbconfoption name="dos charset"/> is used to convert data to the codepage used by your DOS clients.
561 If you do not have any DOS clients, you can safely ignore this message. </para>
562
563 <para>
564 CP850 should be supported by your local iconv implementation. Make sure you have all the required packages installed.
565 If you compiled Samba from source, make sure that the configure process found iconv. This can be
566 confirmed by checking the <filename>config.log</filename> file that is generated when
567 <command>configure</command> is executed.</para>
568 </sect2>
569</sect1>
570
571</chapter>
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