# EGLIBC-&eglibc-version;

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

## Installation of EGLIBC

Some packages outside of CLFS suggest installing GNU libiconv in order to translate data from one encoding to another. The project's home page () says This library provides an `iconv()` implementation, for use on systems which don't have one, or whose implementation cannot convert from/to Unicode. EGLIBC provides an `iconv()` implementation and can convert from/to Unicode, therefore libiconv is not required on a CLFS system.

At the end of the installation, the build system will run a sanity test to make sure everything installed properly. This script will attempt to test for a library that is only used in the test suite and is never installed. Prevent the script from testing for this library with the following command:

    sed -i 's/\(&& $name ne\) "db1"/ & \1 "nss_test1"/' scripts/test-installation.pl

This same script performs its tests by attempting to compile test programs against certain libraries. However it does not specify the ld.so, and our toolchain is still configured to use the one in /tools. The following set of commands will force the script to use the complete path of the new ld.so that was just installed:

    LINKER=$(readelf -l /tools/bin/bash | sed -n 's@.*interpret.*/tools\(.*\)]$@\1@p')
    sed -i "s|libs -o|libs -L/usr/lib -Wl,-dynamic-linker=${LINKER} -o|" \
      scripts/test-installation.pl
    unset LINKER

The following patch fixes an issue that can cause ALSA to crash:

    patch -Np1 -i ../&eglibc-fixes-patch;

The EGLIBC build system is self-contained and will install perfectly, even though the compiler specs file and linker are still pointing at `/tools`. The specs and linker cannot be adjusted before the EGLIBC install because the EGLIBC Autoconf tests would give false results and defeat the goal of achieving a clean build.

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

    mkdir -v ../eglibc-build
    cd ../eglibc-build

Prepare EGLIBC for compilation:

    ../eglibc-&eglibc-version;/configure --prefix=/usr \
        --disable-profile --enable-kernel=2.6.32 --libexecdir=/usr/lib/eglibc

## The meaning of the new configure option:

`--libexecdir=/usr/lib/eglibc`

- This changes the location of the `pt_chown` program from its default of `/usr/libexec` to `/usr/lib/eglibc`.

Compile the package:

    make

The test suite for EGLIBC is considered critical. Do not skip it under any circumstance.

Before running the tests, copy a file from the source tree into our build tree to prevent a couple of test failures, then run the tests:

    cp -v ../eglibc-&eglibc-version;/iconvdata/gconv-modules iconvdata
    make -k check 2>&1 | tee eglibc-check-log; grep Error eglibc-check-log

The EGLIBC test suite is highly dependent on certain functions of the host system, in particular the kernel. The posix/annexc test normally fails and you should see `Error 1 (ignored)` in the output. Apart from this, the EGLIBC test suite is always expected to pass. However, in certain circumstances, some failures are unavoidable. If a test fails because of a missing program (or missing symbolic link), or a segfault, you will see an error code greater than 127 and the details will be in the log. More commonly, tests will fail with `Error 2` - for these, the contents of the corresponding `.out` file, e.g. `posix/annexc.out` may be informative. Here is a list of the most common issues:

- The math tests sometimes fail. Certain optimization settings are known to be a factor here.

- If you have mounted the CLFS partition with the `noatime` option, the atime test will fail. As mentioned in ch-partitioning-mounting, do not use the `noatime` option while building CLFS.

- When running on older and slower hardware, some tests can fail because of test timeouts being exceeded.

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

    touch /etc/ld.so.conf

Install the package:

    make install

Install NIS and RPC related headers that are not installed by default.

    cp -v ../eglibc-&eglibc-version;/sunrpc/rpc/*.h /usr/include/rpc
    cp -v ../eglibc-&eglibc-version;/sunrpc/rpcsvc/*.h /usr/include/rpcsvc
    cp -v ../eglibc-&eglibc-version;/nis/rpcsvc/*.h /usr/include/rpcsvc

## Internationalization

The locales that can make the system respond in a different language were not installed by the above command. Install them with:

    make localedata/install-locales

To save time, an alternative to running the previous command (which generates and installs every locale listed in the `eglibc-&eglibc-version;/localedata/SUPPORTED` file) is to install only those locales that are wanted and needed. This can be achieved by using the `localedef` command. Information on this command is located in the `INSTALL` file in the EGLIBC source. However, there are a number of locales that are essential in order for the tests of future packages to pass, in particular, the libstdc++ tests from GCC. The following instructions, instead of the `install-locales` target used above, will install the minimum set of locales necessary for the tests to run successfully:

    mkdir -pv /usr/lib/locale
    localedef -i cs_CZ -f UTF-8 cs_CZ.UTF-8
    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

Some locales installed by the `make localedata/install-locales` command above are not properly supported by some applications that are in CLFS and CBLFS. Because of the various problems that arise due to application programmers making assumptions that break in such locales, CLFS should not be used in locales that utilize multibyte character sets (including UTF-8) or right-to-left writing order. Numerous unofficial and unstable patches are required to fix these problems, and it has been decided by the CLFS developers not to support such complex locales at this time. This applies to the ja_JP and fa_IR locales as well—they have been installed only for GCC and Gettext tests to pass, and the `watch` program (part of the Procps package) does not work properly in them. Various attempts to circumvent these restrictions are documented in internationalization-related hints.

## Configuring EGLIBC

The `/etc/nsswitch.conf` file needs to be created because, although EGLIBC provides defaults when this file is missing or corrupt, the EGLIBC defaults do not work well in a networked environment. The time zone also needs to be configured.

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

    hosts: files dns
    networks: files

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

    # End /etc/nsswitch.conf
    EOF

To determine the local time zone, run the following script:

    tzselect

After answering a few questions about the location, the script will output the name of the time zone (e.g., EST5EDT or Canada/Eastern). Then create the `/etc/localtime` file by running:

    cp -v --remove-destination /usr/share/zoneinfo/[xxx] \
        /etc/localtime

Replace `[xxx]` with the name of the time zone that `tzselect` provided (e.g., Canada/Eastern).

## The meaning of the cp option:

`--remove-destination`

- This is needed to force removal of the already existing symbolic link. The reason for copying the file instead of using a symlink is to cover the situation where `/usr` is on a separate partition. This could be important when booted into single user mode.

## Configuring The 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 as they are run. However, if there are libraries in directories other than `/lib` and `/usr/lib`, these need to be added to the `/etc/ld.so.conf` file in order 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 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 EGLIBC

Installed programs Installed libraries Installed directories
- catchsegv, gencat, getconf, getent, iconv, iconvconfig, ldconfig, ldd, lddlibc4, locale, localedef, makedb, mtrace, nscd, pcprofiledump, pldd, pt_chown, rpcgen, sln, sprof, tzselect, xtrace,zdump, and zic ld.so, libBrokenLocale.[a,so], libSegFault.so, libanl.[a,so], libbsd-compat.a, libc.[a,so], libc_nonshared.a, libcidn.[a,so], 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], libpthread_nonshared.a, libresolv.[a,so], librpcsvc.a, librt.[a,so], libthread_db.so, and libutil.[a,so] /usr/include/arpa, /usr/include/bits, /usr/include/gnu, /usr/include/net, /usr/include/netash, /usr/include/netatalk, /usr/include/netax25, /usr/include/neteconet, /usr/include/netinet, /usr/include/netipx, /usr/include/netiucv, /usr/include/netpacket, /usr/include/netrom, /usr/include/netrose, /usr/include/nfs, /usr/include/protocols, /usr/include/rpc, /usr/include/rpcsvc, /usr/include/sys, /usr/lib/gconv, /usr/lib/eglibc, /usr/lib/locale, /usr/share/i18n, /usr/share/zoneinfo, /var/cache/ldconfig

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

`iconv`

- Performs character set conversion

`iconvconfig`

- Creates fastloading `iconv` module configuration files

`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`

- Tells the compiler to enable or disable the use of POSIX locales for built-in operations

`localedef`

- Compiles locale specifications

`makedb`

- Creates a simple database from textual input

`mtrace`

- Reads and interprets a memory trace file and displays a summary in human-readable format

`nscd`

- A daemon that provides a cache for the most common name service requests

`pcprofiledump`

- Dumps information generated by PC profiling

`pldd`

- Lists dynamic shared objects used by running processes

`pt_chown`

- 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 Remote Procecure Call (RPC) protocol

`sln`

- A statically linked program that creates symbolic links

`sotruss`

- Traces shared library procedure calls of a specified command

`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`

- The time zone dumper

`zic`

- The time zone compiler

`ld.so`

- The helper program for shared library executables

`libBrokenLocale`

- Used by programs, such as Mozilla, to solve broken locales

`libSegFault`

- The segmentation fault signal handler

`libanl`

- An asynchronous name lookup library

`libbsd-compat`

- Provides the portability needed in order to run certain Berkey Software Distribution (BSD) programs under Linux

`libc`

- The main C library

`libcidn`

- Used internally by EGLIBC for handling internationalized domain names in the `getaddrinfo()` function

`libcrypt`

- The cryptography library

`libdl`

- The dynamic linking interface library

`libg`

- A runtime library for `g++`

`libieee`

- The Institute of Electrical and Electronic Engineers (IEEE) floating point library

`libm`

- The mathematical library

`libmcheck`

- Contains code run at boot

`libmemusage`

- Used by `memusage` (included in EGLIBC, but not built in a base CLFS system as it has additional dependencies) to help collect information about the memory usage of a program

`libnsl`

- The network services library

`libnss`

- The Name Service Switch libraries, containing functions for resolving host names, user names, group names, aliases, services, protocols, etc.

`libpcprofile`

- Contains profiling functions used to track the amount of CPU time spent in specific source code lines

`libpthread`

- The POSIX threads library

`libresolv`

- Contains functions for creating, sending, and interpreting packets to the Internet domain name servers

`librpcsvc`

- Contains 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