Using UTF-8 locales in [B]LFS

AUTHOR: Alexander E. Patrakov
DATE: 2003-11-06
LICENSE: Public Domain
SYNOPSIS: Using UTF-8 locales in [B]LFS
DESCRIPTION:
This hint explains what should be changed in the LFS and BLFS instructions
curent at the time of this writing in order to use locales such as ru_RU.UTF-8.

PREREQUISITES: LFS 5.1-pre1 or later, good knowledge of C
CONFLICTS: compressed manual pages

*** NOTE ***
This hint is not maintained by the author.
***

CHANGELOG:
2003-11-06: Initial submission
2004-02-25: Added some BLFS packages

HINT:

IMPORTANT INFORMATION

Don't follow this hint unless you are prepared to fix broken things! I never
had a full BLFS install, and of course because of that some packages that
are broken in UTF-8 locales may well be missing from this hint.

Also, please don't ask support questions related to this hint on mailing lists
hosted on linuxfromscratch.org (and of course don't provide support yourself)
if you can't answer the questions at the end of the hint.

Also note that while our goal is to move to the international UTF-8 encoding,
we have to disable internationalization completely in some older applications.
So this hint really becomes an antihint: we gain nothing except compatibility
with bleeding-edge RedHat-like distros in their default configuration, and
lost... lost what we were aiming to get --- internationalization.

Once again, don't follow this hint blindly.

BIG WARNING: you will probably have to convert ALL your documents.

Part 1. INTRODUCTION

1. Single-byte and double-byte encodings and UTF-8: what's wrong

Most Eropean languages have a relatively short alphabet (less than 40
characters). This makes it possible to create a represent the
characters of that alphabet (both upper-case and lower-case), English alphabet,
digits and punctuation with a single byte. The result is known as a single-byte
encoding. An example of such encoding is KOI8-R, commonly used in Russia. All
single-byte encodings are ASCII-compatible in the sense that characters
representable in ASCII are also representable in these encodings and have the
same code. They are also reverse-ASCII-compatible in the sense that every byte
with the value less than 0x7f represents the same character as it does in
ASCII. Current LFS and BLFS work well with such encodings.

This approach doesn't work with Asian languages such as Chinese, Japanese and
Korean (denoted together as CJK further in this hint). They have more than 256
different characters, because single characters represent syllables and even
words. So called double-byte encodings are used with these languages. They
represent English letters, digits and punctuation with single bytes equal to
ASCII representation of those characters. To represent native CJK characters,
two-byte sequences are used. Such encodings are called double-byte. An
example is GB2312, used in China. Since CJK characters are twice as wide as
English ones in monospaced font, the "on-screen" width of a string encoded with
such methods is directly proportional to the number of bytes in it (there is
one exception: any two-byte sequence starting with 0x8e byte in EUC-JP takes as
much space as an English letter). LFS and BLFS don't work well with Asian
languages and double-byte encodings because of two reasons:

1) It is impossible to display double-width characters on a Linux console (even
on a framebuffer console) without additional programs that are not in the book.
Installation of e.g. zhcon corrects this.

2) Some assumptions that work with single-byte encodings fail with double-byte
ones. First, some double-byte encodings are not reverse-ASCII-compatible: a
byte with value less than 0x7f can be either an ASCII-representable character
or a second byte of a two-byte sequence. Second, correctly finding the n-th
character in a string is a complex task because some characters occupy one
byte, and some characters are represented by two-byte sequences. Software that
makes bad assumptions needs to be either patched or not installed at all.

Today there is a need to encode multilingual texts. E.g., foreign clients of
companies don't want their names to be distorted up to unreconinzable state by
a chain of multiple transliterations. Since all single-byte and double-byte
encodings are capable of representing characters of at most two alphabets
(english + national), there is a need for a new character set to encode
multilingual texts. Such character set exists and it is named Unicode.

UTF-8 is a method of representing Unicode text with a stream of
8-bit bytes. The resulting stream is both ASCII-compatible and
reverse-ASCII-compatible. A single character can occypy from 1 to 4 bytes. Many
current distributions of Linux configure locales using the UTF-8 character
encoding by default. This doesn't work with (B)LFS for the same reasons as with
double-byte encodings. However,

1) There is no framebuffer-based terminal that is capable of displaying the
full range of Unicode characters (if one doesn't count Debian-specific bterm
from the "bogl" package, bogl = Ben's Own Graphics Library).
Fortunately, it is not needed in most cases. Linux console is capable of
displaying Latin (including accented), Greek, Arabian and Cyrillic
characters together even without framebuffer. Also, xterm works just fine.

2) There is one more assumption that breaks with UTF-8. The relation of
on-screen width of a string to the number of bytes in it is very complex.
That's why e.g. Midnight Commander works with double-byte encodings, but
doesn't work with UTF-8.

3) Many packages in UTF-8 locale fail to provide compatibility with older
doculents saved in traditional single-byte or double-byte encoding.

Part 1. LFS PACKAGES

1. Suggested changes to the installation instructions

The following packages should be configured differently in Chapter 6:
- ncurses
- vim
- man

1a. Modified Ncurses installation instructions

First of all, you need NCurses 5.4. Get it from

http://ftp.gnu.org/gnu/ncurses/ncurses-5.4.tar.gz

The new Ncurses version has experimental support for wide characters.
According to the output of ./configure --help, it is activated by passing
the --enable-widec argument to ./configure. The resulting libraries are
binary-incompatible with "normal" ncurses and therefore a letter "w" is
appended automatically to their names: libncursesw.so.5.4. For compatibility
with precompiled commercial applications, we will install two versions of
ncurses.

Now we are ready to install the non-wide-character version of ncurses, almost
by the book:

./configure --prefix=/usr --with-shared --without-debug
make
make install

This installs /usr/lib/libncurses.so.5.4. We will move it to /lib later.
Then install a wide-character-enabled version:

make distclean
./configure --prefix=/usr --with-shared --without-debug --enable-widec
make
make install

This installs /usr/lib/libncursesw.so.5.4 and related libraries.

Move important libraries to /lib and correct permissions:

chmod 755 /usr/lib/*.5.4
chmod 644 /usr/lib/libncurses++*.a
mv /usr/lib/libncurses.so.5* /lib
mv /usr/lib/libncursesw.so.5* /lib

Make the symbolic links:

ln -sf ../../lib/libncursesw.so.5 /usr/lib/libncurses.so
ln -sf libncurses.so /usr/lib/libcurses.so
ln -sf ../../lib/libncursesw.so.5 /usr/lib/libncursesw.so
ln -sf libncursesw.so /usr/lib/libcursesw.so

Note the first command. Now all applications trying to link at compile time 
against -lncurses will actually link to the wide-character version,
/lib/libncursesw.so.5. This works, because the two libraries are
source-compatible. At runtime, the linker will happily resolve the dependency
upon libncursesw.so.5. And for precompiled commercial applications that
depend on the ordinary version of ncurses there is /lib/libncurses.so.5.

1b. Modified Vim instructions

For Vim to work correctly in double-byte encodings and in UTF-8, the
--enable-multibye switch has to be added to the ./configure command line. Note
that it is not necessary in BLFS since --with-features= (more than normal)
implies this.

echo '#define SYS_VIMRC_FILE "/etc/vimrc"' >> src/feature.h
echo '#define SYS_GVIMRC_FILE "/etc/gvimrc"' >> src/feature.h
./configure --prefix=/usr --enable-multibyte
make
make install
ln -s vim /usr/bin/vi

Vim is able to edit files in arbitrary encodings if you use UTF-8-based locale.
E.g. to read the file price.txt that is known to be in CP1251 encoding, type:

:e ++enc=cp1251 price.txt

It will be automatically converted. To save the file in KOI8-R encoding under
the name price.koi, type:

:w ++enc=koi8-r price.koi

Vim is even able to automatically detect the character set of the file
being read under some conditions. This works because real texts in most
single-byte and double-byte encodings contain sequences of bytes that are not
valid in UTF-8.

This capability needs to be configured. To do so, create the file /etc/vimrc
with the following contents (replace koi8-r with the name of a single-byte or
double-byte encoding that is mostly often used in your country):

" Begin /etc/vimrc

set nocompatible
set bs=2
set fileencodings=ucs-bom,utf-8,koi8-r

" End /etc/vimrc

For more information, read /usr/share/vim/vim62/doc/mbyte.txt

1c. Modified Man instructions

Since Man internationalization does not work at all in UTF-8 locales (the
messages are still output in single-byte or double-byte encodings, appearing
as lines of unreadable squares on the screen) and because Russian messages are
improperly translated (and offensive!) we will disable NLS. This will not
prevent you from viewing manual pages in your native language. It just means
that messages like "What manual page do you want?" will remain untranslated.

Install the "man" package with the followiing commands:

patch -Np1 -i ../man--manpath.patch
patch -Np1 -i ../man--80cols.patch
patch -Np1 -i ../man--pager.patch

DEFS="-DNONLS" ./configure -default -confdir=/etc +lang all
make
make install

Now we have to decide what to do with manual pages in your native language.
They are provided with the corresponding packages in the single-byte or
double-byte encoding, but not in UTF-8. Therefore, they won't display properly.
There are two solutions to this problem.

The first solution is to store them in the single-byte or double-byte encoding,
i.e. as they come with the corresponding packages, and convert them into UTF-8
on the fly. To do this, search for the line in /etc/man.conf that starts with
"PAGER". Replace it with something like the following:

PAGER           /usr/bin/iconv -c -f koi8-r | /usr/bin/less -isR

(replace koi8-r with your 8-bit or double-byte encoding). Note that this change
does not hurt you if you later switch back to the usual encoding: iconv will
be a no-op. Unfortunately, this doesn't work well with graphical man page
viewers like Yelp (from GNOME-2.4) or Konqueror, since they just ignore the
"PAGER" variable in /etc/man.conf (if they read /etc/man.conf at all) and
assume that manual pages are stored in the character set of the current locale.

The second solution would be to convert manual pages to UTF-8. Unfortunately,
I had no success with this. RedHat provides some patches for groff-1.18.1.
I tried to convert all manual pages into UTF-8 and changed man.conf to have
the line

# WRONG!
NROFF /usr/bin/iconv -c -t koi8-r | /usr/bin/nroff -Tlatin1 -mandoc | /usr/bin/iconv -c -f koi8-r

This didn't work well because some manual pages contain just

.so filename

and don't display properly.

In fact, the *roff specification says that the input must be in iso8859-1
encoding, there is no way to typeset anything except Latin and Greek according
to the specification, and all localized manual pages (even in the single-byte
Cyrillic KOI8-R encoding!) are really a hack and violate the specification.

2. Setting up UTF-8 based locale and environment variables

Some UTF-8 locales (e.g. se_NO.UTF-8) are installed during the

make localedata/install-locales

step while installing glibc. But most of UTF-8 locales must be created
manually, e.g.:

localedef -c -i ru_RU -f UTF-8 ru_RU.UTF-8

The role of the -c switch is to continue the creation of the locale even though
warnings are issued. After the creation of the locale, it is needed to tell
applications to use it. All that is required is to set some environment
variables. An easy "solution" is to add this to your /etc/profile:

# WRONG!!!
export LC_ALL=ru_RU.UTF-8
export LANG=ru_RU.UTF-8

This "solution" is wrong because these variables will be available to processes
started from your login shell, but will not be available to the readline
library that the shell uses. The readline library uses this information e.g. to
determine how many bytes to remove from the input buffer (must be one UTF-8
character) and how many character cells to erase on the screen (again, one
full character) if you press Backspace or Delete key.

Yes, if you _type_ export LC_ALL=ru_RU.UTF-8 in the login shell, then it will
pass this setting to the readline library. But this doesn't work in the shell
startup files. This is a bug in bash. So the correct LC_ALL variable must be
already in the environment when the login shell starts.

If one adds the above LC_ALL and LANG variables into /etc/environment, it will
work for login shells started by the "login" program, but will not work for
shells started by "su" or "sshd" programs. This approach also requires you to
place these variables into /etc/profile so that they will be available from
KDE (the "startkde" script from KDE 3.2.0 sources /etc/profile).

Another approach is to make the login shell set the correct locale variables
and reexecute itself. To accompilsh this, add the following snippet at the
very beginning of your /etc/profile:

if [ "x$LC_ALL" = "x" ]
then
    export LC_ALL=ru_RU.UTF-8
    export LANG=ru_RU.UTF-8
    if ( echo $- | grep -q i )
    then
        exec -a "$0" /bin/bash "$@"
    fi
fi

The $- check is there because /etc/profile is sometimes sourced by other
scripts that run in noninteractive shells. Such shells don't need to be
reexecuted, since you don't want to replace a script that sourced /etc/profile
with an instance of /bin/bash called with the same parameters as the script.

Of course, you will have to replace ru_RU above with something more
appropriate.

If you are using xdm, you also want to include the following lines into the
beginning of /etc/X11/xdm/Xsession:

[ -r /etc/profile ] && . /etc/profile
[ -r $HOME/.bash_profile ] && . $HOME/.bash_profile

Consult the documentation of other display managers for the means to set the
environment in the started session.

3. Setting up Linux console

We will modify the /etc/rc.d/init.d/loadkeys script.

#!/bin/bash
# Begin $rc_base/init.d/loadkeys - Loadkeys Script

# Based on loadkeys script from LFS-3.1 and earlier.
# Rewritten by Gerard Beekmans  - [email protected]
# Modified for UTF-8 locales by Alexander E. Patrakov - [email protected]

source /etc/sysconfig/rc
source $rc_functions

echo -n "Setting screen font..."
for console in /dev/tty[1-6]
do
    (
	setfont
	setfont LatArCyrHeb-16
    )<$console >$console 2>&1
done
evaluate_retval

echo -n "Loading keymap..."
kbd_mode -u
loadkeys ru1 2>/dev/null &&
dumpkeys -c koi8-r | loadkeys --unicode
evaluate_retval

# End $rc_base/init.d/loadkeys

Some comments concerning this script.

1) The empty "setfont" command works around a bug in 2.6 kernels.

2) We don't switch the console output to UTF-8 here. We will do that in
/etc/issue (the idea is stolen from "redhat-style-logon" hint). This is
necessary because otherwise this switching will affect only the first console.
As an alternative, you can write a "for" loop here sending %G to all
virtual consoles.

3) The kbd package does not provide ready-to-use keymaps for UTF-8 locales,
except for Ukrainian one. First, we load the now-wrong ru1 keymap (the numeric
character codes there are valid only for koi8-r character set), then we dump
it replacing numeric codes with human-readable descriptions of characters (e.g.
"cyrillic_small_letter_e"). The resulting keymap is usable in UTF-8 mode, so
we load it with loadkeys --unicode.

Let's create /etc/issue:

echo -e '/033[2J/033[f/033%GWelcome to Linux From Scratch/n' >/etc/issue

The meaning of the escape sequences:
[2J = clear entire screen
[f = move the cursor to the corner of the screen
%G = put the console into UTF-8 mode

Set up screen font and keyboard now, if you don't want to reboot:

/etc/rc.d/init.d/loadkeys

Then kill all agetty processes for them to reread /etc/issue:

killall agetty

4. Conclusion

From your next login, you will use UTF-8 based locale, with all its benefits
and drawbacks.

Known bugs:

- The Caps Lock key does not work on Linux console for national characters.
  The guilty package is kbd.
  
- Some packages don't display line drawing characters in UTF-8 mode on Linux
  console. This is a bug in the packages themselves. See ALSA section below
  for more detailed discussion.

Part 2. BLFS PACKAGES

1. GnuPG

The package itself is internationalized well and supports UTF-8 out of the box.
Unfortunately, some applications (e.g. Enigmail) assume that the output of gpg
is in iso8859-1. For applications that cannot be fixed easily, create the
following script:

#!/bin/sh
export LC_ALL=C
export LANG=C
exec /usr/bin/gpg "$@"

Save it as /usr/bin/gpg-nolocale, give it the "executable" bit and configure
the offending application to use this script instead of the real gpg binary.

2. Emacs

I don't use Emacs at all, but your comments are welcome. Don't expect
any console-based editor except Vim, Emacs and Yudit to work in UTF-8 locale.

3. Slang

Get the patch

http://www.linuxfromscratch.org/patches/downloads/slang/slang-1.4.9-utf8.patch

Install Slang using the following instructions:

patch -Np1 -i ../lang-1.4.9-utf8.patch
./configure --prefix=/usr
make CFLAGS="-O2 -pipe -DUTF8"
make install
make CFLAGS="-O2 -pipe -DUTF8" ELF_CFLAGS="-O2 -pipe -DUTF8" elf
make install-elf
make install-links
chmod 755 /usr/lib/libslang.so.1.4.9

WARNING: you should pass -DUTF-8 in CFLAGS to all applications that depend
on Slang.

4. Aspell

To be done.

5. GPM

GPM cannot cut/paste non-ASCII characters. It is really a limitation of Linux
console. You can google for a kernel patch named

unicode_copypaste_2.4.19.patch.gz

but I would recommend against it. I had crashes and repeatable kernel panics
with it.

6. Zip/Unzip

If you put a file with non-ASCII characters in its name into the archive, you
will be unable to get that name correctly under Windows.

7. Midnight Commander

First, install Slang. Then, get the patch

http://www.linuxfromscratch.org/patches/downloads/mc/mc-4.6.0-utf8.patch

Install Midnight Commander with the following instructions:

patch -Np1 -i ../mc-4.6.0-utf8.patch
CFLAGS="-O2 -pipe -DUTF8" ./configure /
    --prefix=/usr --with-screen=slang /
    
    --what-else-you want, e.g.
    
    --with-vfs --with-samba --enable-charset --without-ext2undel /
    --with-configdir=/etc/samba --with-codepagedir=/usr/share/samba/codepages
make
make install

Unfortunately, this patch is not sufficient. In particular, it is impossible
to view and edit files containing non-ASCII characters using the internal
viewer and editor. Configure Midnight Commander to use an external editor,
e.g. Vim.

8. w3m

You need w3m-m17n, not just a bare w3m. Unfortunately, w3m-m17n-0.4.2 does not
exist yet.

9. Mutt, Pine

I don't use them at all, but Debian has a patch for Mutt.
Your comments are welcome.

10. GTK+-1.2.10

This package's default style files in /etc/gtk don't work in UTF-8 locales.
Changing "koi8-r" to "iso10646-1" fonts in /etc/gtk/gtkrc.ru fixes the problem
with improper fonts for Russians. Beware that KDE also sets GTK styles (in
~/.kde/share/config/gtkrc and ~/.gtkrc), so these files also may need some
manual editing.

11. LessTif

This package does not support UNICODE well.

12. KDEMultimedia

The players show ID3 tags with national characters improperly.

13. Yelp

The problems with manual pages have already been mentioned in Man section.

14. ALSA

Alsamixer 1.0.2 won't show the line drawing characters on Linux console in
UTF-8 mode. This is a bug in alsamixer. The problem is that NCurses must
know whether the Linux console is in UTF-8 mode or not. To do that, NCurses
checks the current locale setting (in the order: LC_ALL, LC_CTYPE, LANG).
Also, it has to compute how many cells a given character occupies. This
requires a valid LC_CTYPE setting.

But this means that a program that links to ncurses must call

setlocale(LC_CTYPE, "")

before initscr(). This patch fixes the issue in alsamixer

http://www.linuxfromscratch.org/patches/downloads/alsa-utils/alsa-utils-1.0.2-locale.patch

After reading the text above and looking at the alsamixer patch, you should
be able to fix this kind of a problem with other packages. Please send
patches to [email protected].

Don't send a patch for the "lxdialog" program that comes with the kernel
sources and is used during "make menuconfig", since that will break Question
2 in the quiz below and I will no longer be able to check whether others are
ready to follow this hint.

15. XMMS

This package will not show ID3 tags properly out of the box, because they are
usually in the windowsish single-byte or double-byte encoding and not in UTF-8.
The patch from http://rusxmms.sourceforge.net/ helps.

16. Dillo

This package does not support UNICODE.

17. XSane

The gtk+-1.2.10 version is affected by a bug in gtk+ style support
and does not work properly even in ru_RU.koi8r locale. To work around
the problem, don't build the GIMP plugin --- then XSane will link against GTK2.

18. Xpdf

Since this package depends on LessTif, the support of UTF-8 in the GUI is
rather poor. E.g., the filenames in the fileselector show improperly. But
the non-GUI tool, pstotext, works flawlessly and can extract text in the UTF-8
encoding from PDF files.

19. A2ps

This package does not support UNICODE.

20. TeX

To use UTF-8 as an input encoding with TeX, you should download the following
package:

http://www.unruh.de/DniQ/latex/unicode/unicode.tgz

Just unpack it into /usr/share/texmf/tex, remove all files except

ucs/*.sty, ucs/*.def, ucs/data/*

and then run mktexlsr. Then you will be able to write

/usepackage[utf-8]{inputenc}

in the document preamble, but I doubt that anyone else will be able to TeX
your documents.

If you want someone else to be able to extract text in UTF-8 encoding from
your PDF files generated by PDFTeX or dvipdfm, you should also install
the "cm-super" font package from CTAN.

Part 3. CONCLUSIONS

Probably you understand from reading the above that UTF-8 causes more trouble
than merit. If you followed this hint, I hope that I didn't damage your system
irreversibly.

Please post your deviations and report other broken packages to

[email protected]

APPENDIX A. QUIZ

You should follow the hint only if you know all the answers.

1) The non-wide character version of ncurses 5.4 uses poor-man line-drawing
   characters on Linux console in UTF-8 mode.

   What other terminal type is affected by this? Where (which file and line)
   is the check? Where is the piece of code that substitutes these poor-man
   line-drawng characters instead of those which came from the terminfo
   database? Where does ncurses 5.4 check the current locale?

2) Linux kernel build process uses the "lxdialog" program during the
   "make menuconfig" step. Unfortunately, lxdialog has the same bug as
   alsamixer (see the hint).
   
   Can you make a patch for lxdialog yourself?