Glibc-2.3.3
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## Glibc-2.3.3

The Glibc package contains the main C library. This library provides all the basic routines for allocating memory, searching directories, opening and closing files, reading and writing them, string handling, pattern matching, arithmetic, and so on.

    Approximate build time:  12.3 SBU
    Required disk space:     784 MB

Glibc installation depends on: Bash, Binutils, Coreutils, Diffutils, Gawk, GCC, Gettext, Grep, Make, Perl, Sed, Texinfo.

### Installation of Glibc

The Glibc build system is very well self-contained and will install perfectly, even though our compiler specs file and linker are still pointing at `/tools`. We cannot adjust the specs and linker before the Glibc install, because the Glibc autoconf tests would then give bogus results and thus defeat our goal of achieving a clean build.

Before starting to build Glibc, remember to unset any environment variables that override the default optimization flags.

The Glibc documentation recommends building Glibc outside of the source directory in a dedicated build directory:

    mkdir ../glibc-build
    cd ../glibc-build

Now prepare Glibc for compilation:

    ../glibc-2.3.3-20031202/configure --prefix=/usr \
        --disable-profile --enable-add-ons=linuxthreads \
        --libexecdir=/usr/lib --with-headers=/usr/include \
        --without-cvs

The meaning of the new configure options:

- `--libexecdir=/usr/lib`: This changes the location of the `pt_chown` program from its default of `/usr/libexec` to `/usr/lib`. The use of libexec is considered not to be FHS-compliant because the FHS doesn't even mention it.

- `--with-headers=/usr/include`: This ensures that the kernel headers in `/usr/include` are used for this build. If you don't pass this switch then the headers from `/tools/include` are used which of course is not ideal (although they should be identical). Using this switch has the advantage that you will be informed immediately should you have forgotten to install the kernel headers into `/usr/include`.

Compile the package:

    make

| Important
The test suite for Glibc in this section is considered critical. Our advice is to not skip it under any circumstance.

Test the results:

    make check

The test suite notes from the section called “Glibc-2.3.3” are still very much appropriate here. Be sure to refer back there should you have any doubts.

Though it is a harmless message, the install stage of Glibc will complain about the absence of `/etc/ld.so.conf`. Fix this annoying little warning with:

    touch /etc/ld.so.conf

And install the package:

    make install

The locales that can make your system respond in a different language weren't installed by the above command. Do it with this:

    make localedata/install-locales

An alternative to running the previous command is to install only those locales which you need or want. This can be achieved by using the localedef command. Information on this can be found in the `INSTALL` file in the Glibc source. However, there are a number of locales that are essential for the tests of future packages to pass, in particular, the libstdc++ tests from GCC. The following instructions, instead of the install-locales target above, will install the minimum set of locales necessary for the tests to run successfully:

    mkdir -p /usr/lib/locale
    localedef -i de_DE -f ISO-8859-1 de_DE
    localedef -i de_DE@euro -f ISO-8859-15 de_DE@euro
    localedef -i en_HK -f ISO-8859-1 en_HK
    localedef -i en_PH -f ISO-8859-1 en_PH
    localedef -i en_US -f ISO-8859-1 en_US
    localedef -i es_MX -f ISO-8859-1 es_MX
    localedef -i fa_IR -f UTF-8 fa_IR
    localedef -i fr_FR -f ISO-8859-1 fr_FR
    localedef -i fr_FR@euro -f ISO-8859-15 fr_FR@euro
    localedef -i it_IT -f ISO-8859-1 it_IT
    localedef -i ja_JP -f EUC-JP ja_JP

Finally, build the linuxthreads man pages:

    make -C ../glibc-2.3.3-20031202/linuxthreads/man

And install these pages:

    make -C ../glibc-2.3.3-20031202/linuxthreads/man install

### Configuring Glibc

We need to create the `/etc/nsswitch.conf` file, because, although Glibc provides defaults when this file is missing or corrupt, the Glibc defaults don't work well with networking. Also, our time zone needs to be set up.

Create a new file `/etc/nsswitch.conf` by running the following:

    cat > /etc/nsswitch.conf << "EOF"
    # Begin /etc/nsswitch.conf

    passwd: files
    group: files
    shadow: files

    publickey: files

    hosts: files dns
    networks: files

    protocols: db files
    services: db files
    ethers: db files
    rpc: db files

    netgroup: db files

    # End /etc/nsswitch.conf
    EOF

To find out what time zone you're in, run the following script:

    tzselect

When you've answered a few questions about your location, the script will output the name of your time zone, something like EST5EDT or Canada/Eastern. Then create the `/etc/localtime` file by running:

    cp --remove-destination /usr/share/zoneinfo/Canada/Eastern /etc/localtime

The meaning of the option:

- `--remove-destination`: This is needed to force removal of the already existing symbolic link. The reason why we copy instead of symlink is to cover the situation where `/usr` is on a separate partition. This could matter, for example, when booted into single user mode.

Of course, instead of Canada/Eastern, fill in the name of the time zone that the tzselect script gave you.

### Configuring Dynamic Loader

By default, the dynamic loader (`/lib/ld-linux.so.2`) searches through `/lib` and `/usr/lib` for dynamic libraries that are needed by programs when you run them. However, if there are libraries in directories other than `/lib` and `/usr/lib`, you need to add them to the `/etc/ld.so.conf` file for the dynamic loader to find them. Two directories that are commonly known to contain additional libraries are `/usr/local/lib` and `/opt/lib`, so we add those directories to the dynamic loader's search path.

Create a new file `/etc/ld.so.conf` by running the following:

    cat > /etc/ld.so.conf << "EOF"
    # Begin /etc/ld.so.conf

    /usr/local/lib
    /opt/lib

    # End /etc/ld.so.conf
    EOF

### Contents of Glibc

Installed programs: catchsegv, gencat, getconf, getent, glibcbug, iconv, iconvconfig, ldconfig, ldd, lddlibc4, locale, localedef, mtrace, nscd, nscd_nischeck, pcprofiledump, pt_chown, rpcgen, rpcinfo, sln, sprof, tzselect, xtrace, zdump and zic

Installed libraries: ld.so, libBrokenLocale.[a,so], libSegFault.so, libanl.[a,so], libbsd-compat.a, libc.[a,so], libc_nonshared.a, libcrypt.[a,so], libdl.[a,so], libg.a, libieee.a, libm.[a,so], libmcheck.a, libmemusage.so, libnsl.a, libnss_compat.so, libnss_dns.so, libnss_files.so, libnss_hesiod.so, libnss_nis.so, libnss_nisplus.so, libpcprofile.so, libpthread.[a,so], libresolv.[a,so], librpcsvc.a, librt.[a,so], libthread_db.so and libutil.[a,so]

### Short descriptions

catchsegv can be used to create a stack trace when a program terminates with a segmentation fault.

gencat generates message catalogues.

getconf displays the system configuration values for file system specific variables.

getent gets entries from an administrative database.

glibcbug creates a bug report and mails it to the bug email address.

iconv performs character set conversion.

iconvconfig creates fastloading iconv module configuration file.

ldconfig configures the dynamic linker runtime bindings.

ldd reports which shared libraries are required by each given program or shared library.

lddlibc4 assists ldd with object files.

locale is a Perl program that tells the compiler to enable or disable the use of POSIX locales for built-in operations.

localedef compiles locale specifications.

mtrace...

nscd is a name service cache daemon providing a cache for the most common name service requests.

nscd_nischeck checks whether or not secure mode is necessary for NIS+ lookup.

pcprofiledump dumps information generated by PC profiling.

pt_chown is a helper program for grantpt to set the owner, group and access permissions of a slave pseudo terminal.

rpcgen generates C code to implement the RPC protocol.

rpcinfo makes an RPC call to an RPC server.

sln is used to make symbolic links. The program is statically linked, so it is useful for making symbolic links to dynamic libraries if the dynamic linking system for some reason is nonfunctional.

sprof reads and displays shared object profiling data.

tzselect asks the user about the location of the system and reports the corresponding time zone description.

xtrace traces the execution of a program by printing the currently executed function.

zdump is the time zone dumper.

zic is the time zone compiler.

ld.so is the helper program for shared library executables.

libBrokenLocale is used by programs, such as Mozilla, to solve broken locales.

libSegFault is a segmentation fault signal handler. It tries to catch segfaults.

libanl is an asynchronous name lookup library.

libbsd-compat provides the portability needed in order to run certain BSD programs under Linux.

libc is the main C library -- a collection of commonly used functions.

libcrypt is the cryptography library.

libdl is the dynamic linking interface library.

libg is a runtime library for g++.

libieee is the IEEE floating point library.

libm is the mathematical library.

libmcheck contains code run at boot.

libmemusage is used by memusage to help collect information about the memory usage of a program.

libnsl is the network services library.

libnss* are the Name Service Switch libraries, containing functions for resolving host names, user names, group names, aliases, services, protocols,and the like.

libpcprofile contains profiling functions used to track the amount of CPU time spent in which source code lines.

libpthread is the POSIX threads library.

libresolv contains functions for creating, sending, and interpreting packets to the Internet domain name servers.

librpcsvccontains functions providing miscellaneous RPC services.

librt contains functions providing most of the interfaces specified by the POSIX.1b Realtime Extension.

libthread_db contains functions useful for building debuggers for multi-threaded programs.

libutil contains code for "standard" functions used in many different Unix utilities.

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