Installation of Glibc
First, apply some changes from upstream:
patch -Np1 -i ../glibc-2.42-upstream_fixes-1.patch
Some of the Glibc programs use the non-FHS compliant
/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-2.42-fhs-1.patch
Now fix an issue which may break Valgrind in BLFS:
sed -e '/unistd.h/i #include <string.h>' \
-e '/libc_rwlock_init/c\
__libc_rwlock_define_initialized (, reset_lock);\
memcpy (&lock, &reset_lock, sizeof (lock));' \
-i stdlib/abort.c The Glibc documentation recommends building Glibc
in a dedicated build directory:
mkdir -v build
cd build
Ensure that the ldconfig and sln
utilities will be installed into
/usr/sbin:
echo "rootsbindir=/usr/sbin" > configparms
Prepare Glibc for compilation:
../configure --prefix=/usr \
--disable-werror \
--disable-nscd \
libc_cv_slibdir=/usr/lib \
--enable-stack-protector=strong \
--enable-kernel=5.4The meaning of the configure options:
--disable-werrorThis option disables the -Werror option passed to
GCC. This is necessary for running the test suite.
--enable-kernel=5.4This option tells the build system that this Glibc may
be used with kernels as old as 5.4. This means generating
workarounds in case a system call introduced in a later version
cannot be used.
--enable-stack-protector=strongThis option increases system security by adding
extra code to check for buffer overflows, such as stack
smashing attacks. Note that Glibc always explicitly overrides
the default of GCC, so this option is still needed even though
we've already specified --enable-default-ssp for
GCC.
--disable-nscdDo not build the name service cache daemon which is no
longer used.
libc_cv_slibdir=/usr/libThis variable sets the correct library for all
systems. We do not want lib64 to be used.
Compile the package:
make
![[Important]](../images/important.png)
Important
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. The test failures listed below
are usually safe to ignore.
make check
You may see some test failures. The Glibc test suite is
somewhat dependent on the host system. A few failures out of
over 6000 tests can generally be ignored. This is a list of the
most common issues seen for recent versions of LFS:
io/tst-lchmod
is known to fail in the LFS chroot environment.
Some tests, for example
nss/tst-nss-files-hosts-multi and
nptl/tst-thread-affinity*
are known to fail due to a timeout (especially when the system is
relatively slow and/or running the test suite with multiple
parallel make jobs). These tests can be identified with:
grep "Timed out" $(find -name \*.out)
It's possible to re-run a single test with enlarged timeout
with
TIMEOUTFACTOR=<factor>
make test t=<test name>.
For example, TIMEOUTFACTOR=10 make test
t=nss/tst-nss-files-hosts-multi will re-run
nss/tst-nss-files-hosts-multi with ten times
the original timeout.
Additionally, some tests may fail with a relatively old CPU
model (for example
elf/tst-cpu-features-cpuinfo) or host kernel
version (for example
stdlib/tst-arc4random-thread).
Though it is a harmless message, the install stage of Glibc will
complain about the absence of /etc/ld.so.conf.
Prevent this warning with:
touch /etc/ld.so.conf
Fix the Makefile to skip an outdated sanity check
that fails with a modern Glibc configuration:
sed '/test-installation/s@$(PERL)@echo not running@' -i ../Makefile
Important
If upgrading Glibc to a new minor version (for example, from
Glibc-2.36 to Glibc-2.42) on a running LFS system, you
need to take some extra precautions to avoid breaking the system:
Upgrading Glibc on a LFS system prior to 11.0 (exclusive) is
not supported. Rebuild LFS if you are running such an old LFS
system but you need a newer Glibc.
If upgrading on a LFS system prior to 12.0 (exclusive), install
Libxcrypt following
the section called “Libxcrypt-4.5.1.” In addition to
a normal Libxcrypt installation,
you MUST follow the note in Libxcrypt
section to install
libcrypt.so.1*
(replacing
libcrypt.so.1 from the
prior Glibc installation).
If upgrading on a LFS system prior to 12.1 (exclusive),
remove the nscd program:
rm -f /usr/sbin/nscd
If this system (prior to LFS 12.1, exclusive) is based on
Systemd, it's also needed to disable and stop the
nscd service now:
systemctl disable --now nscd
Upgrade the kernel and reboot if it's older than 5.4
(check the current version with uname -r)
or if you want to upgrade it anyway, following
'ch-bootable-kernel'.
Upgrade the kernel API headers if it's older than 5.4
(check the current version with
cat /usr/include/linux/version.h)
or if you want to upgrade it anyway, following
the section called “Linux-6.12.58 API Headers” (but removing
$LFS from the cp command).
Perform a DESTDIR installation and upgrade
the Glibc shared libraries on the system using one single
install command:
make DESTDIR=$PWD/dest install
install -vm755 dest/usr/lib/*.so.* /usr/lib
It's imperative to strictly follow these steps above unless you
completely understand what you are doing.
Any unexpected deviation may render the
system completely unusable. YOU ARE WARNED.
Then continue to run the make install command,
the sed command against
/usr/bin/ldd, and the commands to install
the locales. Once they are finished, reboot the system
immediately.
When the system has successfully rebooted, if you are running
a LFS system prior to 12.0 (exclusive) where GCC was not built
with the --disable-fixincludes option,
move two GCC headers into a better location and
remove the stale “fixed” copies of the Glibc headers:
DIR=$(dirname $(gcc -print-libgcc-file-name))
[ -e $DIR/include/limits.h ] || mv $DIR/include{-fixed,}/limits.h
[ -e $DIR/include/syslimits.h ] || mv $DIR/include{-fixed,}/syslimits.h
rm -rfv $DIR/include-fixed/*
unset DIRInstall the package:
make install
Fix a hardcoded path to the executable loader in the
ldd script:
sed '/RTLDLIST=/s@/usr@@g' -i /usr/bin/ldd
Next, install the locales that can make the system respond in a
different language. None of these locales are required, but if some of them
are missing, the test suites of some packages will skip important
test cases.
Individual locales can be installed using the
localedef program. E.g., the second
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:
localedef -i C -f UTF-8 C.UTF-8
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 el_GR -f ISO-8859-7 el_GR
localedef -i en_GB -f ISO-8859-1 en_GB
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_ES -f ISO-8859-15 es_ES@euro
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 is_IS -f ISO-8859-1 is_IS
localedef -i is_IS -f UTF-8 is_IS.UTF-8
localedef -i it_IT -f ISO-8859-1 it_IT
localedef -i it_IT -f ISO-8859-15 it_IT@euro
localedef -i it_IT -f UTF-8 it_IT.UTF-8
localedef -i ja_JP -f EUC-JP ja_JP
localedef -i ja_JP -f UTF-8 ja_JP.UTF-8
localedef -i nl_NL@euro -f ISO-8859-15 nl_NL@euro
localedef -i ru_RU -f KOI8-R ru_RU.KOI8-R
localedef -i ru_RU -f UTF-8 ru_RU.UTF-8
localedef -i se_NO -f UTF-8 se_NO.UTF-8
localedef -i ta_IN -f UTF-8 ta_IN.UTF-8
localedef -i tr_TR -f UTF-8 tr_TR.UTF-8
localedef -i zh_CN -f GB18030 zh_CN.GB18030
localedef -i zh_HK -f BIG5-HKSCS zh_HK.BIG5-HKSCS
localedef -i zh_TW -f UTF-8 zh_TW.UTF-8
In addition, install the locale for your own country, language and
character set.
Alternatively, install all the locales listed in the
glibc-2.42/localedata/SUPPORTED file
(it includes every locale listed above and many more) at once with the
following time-consuming command:
make localedata/install-locales
![[Note]](../images/note.png)
Note
Glibc now uses libidn2 when resolving internationalized
domain names. This is a run time dependency. If this capability
is needed, the instructions for installing libidn2 are in the
BLFS libidn2 page.
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 systemd
group: files systemd
shadow: files systemd
hosts: mymachines resolve [!UNAVAIL=return] files myhostname 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 ../../tzdata2025b.tar.gz
ZONEINFO=/usr/share/zoneinfo
mkdir -pv $ZONEINFO/{posix,right}
for tz in etcetera southamerica northamerica europe africa antarctica \
asia australasia backward; do
zic -L /dev/null -d $ZONEINFO ${tz}
zic -L /dev/null -d $ZONEINFO/posix ${tz}
zic -L leapseconds -d $ZONEINFO/right ${tz}
done
cp -v zone.tab zone1970.tab iso3166.tab $ZONEINFO
zic -d $ZONEINFO -p America/New_York
unset ZONEINFO tzThe 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
1.9 MB 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 saving time rules
to be in accordance with US rules.
One way to determine the local time zone is to 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.,
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
/usr/lib for dynamic libraries
that are needed by programs as they are run. However, if there are
libraries in directories other than
/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
EOF
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
EOF
mkdir -pv /etc/ld.so.conf.d