6.9. Glibc-2.25

The Glibc 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.

Approximate build time: 20 SBU
Required disk space: 1.5 GB

6.9.1. Installation of Glibc



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

Some of the Glibc programs use non-FHS compilant /var/db directory to store their runtime data. Apply the following patch to make such programs store their runtime data in the FHS-compliant locations:

patch -Np1 -i ../glibc-2.25-fhs-1.patch

First create a compatibility symlink to avoid references to /tools in our final glibc:

ln -sfv /tools/lib/gcc /usr/lib

Determine the GCC include directory and create a symlink for LSB compliance. Additionally, for x86_64, create a compatibility symlink required for the dynamic loader to function correctly:

case $(uname -m) in
    x86)    GCC_INCDIR=/usr/lib/gcc/x86-pc-linux-gnu/7.1.0/include
            ln -s ld-linux.so.2 /lib/ld-lsb.so.3
    x86_64) GCC_INCDIR=/usr/lib/gcc/x86_64-pc-linux-gnu/7.1.0/include
            ln -s ../lib/ld-linux-x86-64.so.2 /lib64
            ln -s ../lib/ld-linux-x86-64.so.2 /lib64/ld-lsb-x86-64.so.3

The Glibc documentation recommends building Glibc in a dedicated build directory:

mkdir -v build
cd       build

Prepare Glibc for compilation:

CC="gcc -isystem $GCC_INCDIR -isystem /usr/include" \
../configure --prefix=/usr                          \
             --disable-werror                       \
             --enable-kernel=2.6.32                 \
             --enable-obsolete-rpc                  \
             --enable-stack-protector=strong        \

The meaning of the options and new configure parameters:

CC="gcc -isystem $GCC_INCDIR -isystem /usr/include"

Setting the location of both gcc and system include directories avoids introduction of invalid paths in debugging symbols.


This option disables the -Werror option passed to GCC. This is necessary for running the test suite.


This option builds older RPC code for use with network file system utilities (nfs).


This option increases system security by adding a known canary (a random integer) to the stack during a function preamble, and checks it when the function returns. If it changed, there was a stack overflow, and the program aborts.


This variable sets the correct library for all systems. We do not want lib64 to be used.

Compile the package:



In this section, the test suite for Glibc is considered critical. Do not skip it under any circumstance.

Generally a few tests do not pass, but you can generally ignore any of the test failures listed below. Now test the build results:

make check

You may see some test failures. The Glibc test suite is somewhat dependent on the host system. This is a list of the most common issues seen for some versions of LFS:

  • posix/tst-getaddrinfo4 and posix/tst-getaddrinfo5 may fail on some architectures.

  • The rt/tst-cputimer1 and rt/tst-cpuclock2 tests have been known to fail. The reason is not completely understood, but indications are that minor timing issues can trigger these failures.

  • The math tests sometimes fail when running on systems where the CPU is not a relatively new Intel or AMD processor.

  • The nptl/tst-thread-affinity-{pthread,pthread2,sched} tests may fail for reasons that have not been determined.

  • Other tests known to fail on some architectures are malloc/tst-malloc-usable and nptl/tst-cleanupx4.

Though it is a harmless message, the install stage of Glibc 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 the configuration file and runtime directory for nscd:

cp -v ../nscd/nscd.conf /etc/nscd.conf
mkdir -pv /var/cache/nscd

Install the systemd support files for nscd:

install -v -Dm644 ../nscd/nscd.tmpfiles /usr/lib/tmpfiles.d/nscd.conf
install -v -Dm644 ../nscd/nscd.service /lib/systemd/system/nscd.service

Next, install the locales that can make the system respond in a different language. None of the locales are required, but if some of them are missing, the test suites of future packages would skip important testcases.

Individual locales can be installed using the localedef program. E.g., the first localedef command below combines the /usr/share/i18n/locales/cs_CZ charset-independent locale definition with the /usr/share/i18n/charmaps/UTF-8.gz charmap definition and appends the result to the /usr/lib/locale/locale-archive file. The following instructions will install the minimum set of locales necessary for the optimal coverage of tests:

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 de_DE -f UTF-8 de_DE.UTF-8
localedef -i en_GB -f UTF-8 en_GB.UTF-8
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 en_US -f UTF-8 en_US.UTF-8
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 fr_FR -f UTF-8 fr_FR.UTF-8
localedef -i it_IT -f ISO-8859-1 it_IT
localedef -i it_IT -f UTF-8 it_IT.UTF-8
localedef -i ja_JP -f EUC-JP ja_JP
localedef -i ru_RU -f KOI8-R ru_RU.KOI8-R
localedef -i ru_RU -f UTF-8 ru_RU.UTF-8
localedef -i tr_TR -f UTF-8 tr_TR.UTF-8
localedef -i zh_CN -f GB18030 zh_CN.GB18030

In addition, install the locale for your own country, language and character set.

Alternatively, install all locales listed in the glibc-2.25/localedata/SUPPORTED file (it includes every locale listed above and many more) at once with the following time-consuming command:

make localedata/install-locales

Then use the localedef command to create and install locales not listed in the glibc-2.25/localedata/SUPPORTED file in the unlikely case you need them.

6.9.2. Configuring Glibc Adding nsswitch.conf

The /etc/nsswitch.conf file needs to be created because the Glibc defaults do not work well in a networked environment.

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 Adding time zone data

Install and set up the time zone data with the following:

tar -xf ../../tzdata2017b.tar.gz

mkdir -pv $ZONEINFO/{posix,right}

for tz in etcetera southamerica northamerica europe africa antarctica  \
          asia australasia backward pacificnew systemv; do
    zic -L /dev/null   -d $ZONEINFO       -y "sh yearistype.sh" ${tz}
    zic -L /dev/null   -d $ZONEINFO/posix -y "sh yearistype.sh" ${tz}
    zic -L leapseconds -d $ZONEINFO/right -y "sh yearistype.sh" ${tz}

cp -v zone.tab zone1970.tab iso3166.tab $ZONEINFO
zic -d $ZONEINFO -p America/New_York

The meaning of the zic commands:

zic -L /dev/null ...

This creates posix time zones, without any leap seconds. It is conventional to put these in both zoneinfo and zoneinfo/posix. It is necessary to put the POSIX time zones in zoneinfo, otherwise various test-suites will report errors. On an embedded system, where space is tight and you do not intend to ever update the time zones, you could save 1.9MB by not using the posix directory, but some applications or test-suites might produce some failures.

zic -L leapseconds ...

This creates right time zones, including leap seconds. On an embedded system, where space is tight and you do not intend to ever update the time zones, or care about the correct time, you could save 1.9MB by omitting the right directory.

zic ... -p ...

This creates the posixrules file. We use New York because POSIX requires the daylight savings time rules to be in accordance with US rules.

One way to determine the local time zone is to run the following script:


After answering a few questions about the location, the script will output the name of the time zone (e.g., America/Edmonton). There are also some other possible time zones listed in /usr/share/zoneinfo such as Canada/Eastern or EST5EDT that are not identified by the script but can be used.

Then create the /etc/localtime file by running:

ln -sfv /usr/share/zoneinfo/<xxx> /etc/localtime

Replace <xxx> with the name of the time zone selected (e.g., Canada/Eastern). 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


If desired, the dynamic loader can also search a directory and include the contents of files found there. Generally the files in this include directory are one line specifying the desired library path. To add this capability run the following commands:

cat >> /etc/ld.so.conf << "EOF"
# Add an include directory
include /etc/ld.so.conf.d/*.conf

mkdir -pv /etc/ld.so.conf.d

6.9.3. Contents of Glibc

Installed programs: catchsegv, gencat, getconf, getent, iconv, iconvconfig, ldconfig, ldd, lddlibc4, locale, localedef, makedb, mtrace, nscd, pldd, rpcgen, sln, sotruss, sprof, tzselect, xtrace, zdump, and zic
Installed libraries: ld-2.25.so, libBrokenLocale.{a,so}, libSegFault.so, libanl.{a,so}, libc.{a,so}, libc_nonshared.a, libcidn.so, libcrypt.{a,so}, libdl.{a,so}, libg.a, libieee.a, libm.{a,so}, libmcheck.a, libmemusage.so, libnsl.{a,so}, libnss_compat.so, libnss_dns.so, libnss_files.so, libnss_hesiod.so, libnss_nis.so, libnss_nisplus.so, libpthread.{a,so}, libpthread_nonshared.a, libresolv.{a,so}, librpcsvc.a, librt.{a,so}, libthread_db.so, and libutil.{a,so}
Installed directories: /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/audit, /usr/lib/gconv, /usr/lib/locale, /usr/libexec/getconf, /usr/share/i18n, /usr/share/zoneinfo, /var/cache/nscd, and /var/lib/nss_db

Short Descriptions


Can be used to create a stack trace when a program terminates with a segmentation fault


Generates message catalogues


Displays the system configuration values for file system specific variables


Gets entries from an administrative database


Performs character set conversion


Creates fastloading iconv module configuration files


Configures the dynamic linker runtime bindings


Reports which shared libraries are required by each given program or shared library


Assists ldd with object files


Prints various information about the current locale


Compiles locale specifications


Creates a simple database from textual input


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


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


Lists dynamic shared objects used by running processes


Generates C code to implement the Remote Procedure Call (RPC) protocol


A statically linked ln program


Traces shared library procedure calls of a specified command


Reads and displays shared object profiling data


Asks the user about the location of the system and reports the corresponding time zone description


Traces the execution of a program by printing the currently executed function


The time zone dumper


The time zone compiler


The helper program for shared library executables


Used internally by Glibc as a gross hack to get broken programs (e.g., some Motif applications) running. See comments in glibc-2.25/locale/broken_cur_max.c for more information


The segmentation fault signal handler, used by catchsegv


An asynchronous name lookup library


The main C library


Used internally by Glibc for handling internationalized domain names in the getaddrinfo() function


The cryptography library


The dynamic linking interface library


Dummy library containing no functions. Previously was a runtime library for g++


Linking in this module forces error handling rules for math functions as defined by the Institute of Electrical and Electronic Engineers (IEEE). The default is POSIX.1 error handling


The mathematical library


Turns on memory allocation checking when linked to


Used by memusage to help collect information about the memory usage of a program


The network services library


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


The POSIX threads library


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


Contains functions providing miscellaneous RPC services


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


Contains functions useful for building debuggers for multi-threaded programs


Contains code for standard functions used in many different Unix utilities