Chapter 27. Unicode/Charsets

-Every industry eventually matures. One of the great areas of maturation is in -the focus that has been given over the past decade to make it possible for anyone -anywhere to use a computer. It has not always been that way, in fact, not so long -ago it was common for software to be written for exclusive use in the country of -origin. -

-Of all the effort that has been brought to bear on providing native language support -for all computer users, the efforts of the Openi18n organization is deserving of -special mention. -

-Samba-2.x supported a single locale through a mechanism called -codepages. Samba-3 is destined to become a truly trans-global -file and printer-sharing platform. -

What Are Charsets and Unicode?

-Computers communicate in numbers. In texts, each number will be -translated to a corresponding letter. The meaning that will be assigned -to a certain number depends on the character set (charset) - that is used. -

-A charset can be seen as a table that is used to translate numbers to -letters. Not all computers use the same charset (there are charsets -with German umlauts, Japanese characters, and so on). Usually a charset contains -256 characters, which means that storing a character with it takes -exactly one byte.

-There are also charsets that support even more characters, -but those need twice as much storage space (or more). These -charsets can contain 256 * 256 = 65536 characters, which -is more than all possible characters one could think of. They are called -multibyte charsets because they use more then one byte to -store one character. -

-A standardized multibyte charset is unicode. -A big advantage of using a multibyte charset is that you only need one; there -is no need to make sure two computers use the same charset when they are -communicating. -

Old Windows clients use single-byte charsets, named -codepages, by Microsoft. However, there is no support for -negotiating the charset to be used in the SMB/CIFS protocol. Thus, you -have to make sure you are using the same charset when talking to an older client. -Newer clients (Windows NT, 200x, XP) talk unicode over the wire. -

Samba and Charsets

-As of Samba-3.0, Samba can (and will) talk unicode over the wire. Internally, -Samba knows of three kinds of character sets: -

unix charset: - This is the charset used internally by your operating system. - The default is UTF-8, which is fine for most - systems, which covers all characters in all languages. The default in previous Samba releases was ASCII. -
display charset: This is the charset Samba will use to print messages - on your screen. It should generally be the same as the unix charset. -
dos charset: This is the charset Samba uses when communicating with - DOS and Windows 9x/Me clients. It will talk unicode to all newer clients. - The default depends on the charsets you have installed on your system. - Run testparm -v | grep "dos charset" to see - what the default is on your system. -

Conversion from Old Names

Because previous Samba versions did not do any charset conversion, -characters in filenames are usually not correct in the UNIX charset but only -for the local charset used by the DOS/Windows clients.

Japanese Charsets

Samba does not work correctly with Japanese charsets yet. Here are -points of attention when setting it up:

You should set mangling method = hash
There are various iconv() implementations around and not - all of them work equally well. glibc2's iconv() has a critical problem - in CP932. libiconv-1.8 works with CP932 but still has some problems and - does not work with EUC-JP.
You should set dos charset = CP932, not - Shift_JIS, SJIS.
Currently only UNIX charset = CP932 - will work (but still has some problems...) because of iconv() issues. - UNIX charset = EUC-JP does not work well because of - iconv() issues.
Currently Samba-3.0 does not support UNIX charset = UTF8-MAC/CAP/HEX/JIS*.

More information (in Japanese) is available at: http://www.atmarkit.co.jp/flinux/special/samba3/samba3a.html.

Common Errors

CP850.so Can't Be Found

“Samba is complaining about a missing CP850.so file.”

Answer: CP850 is the default dos charset. - The dos charset is used to convert data to the codepage used by your dos clients. - If you do not have any dos clients, you can safely ignore this message.

CP850 should be supported by your local iconv implementation. Make sure you have all the required packages installed. - If you compiled Samba from source, make sure to configure found iconv.

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