%general-entities; ]> glibc &glibc-version;
&glibc-url;
Glibc-&glibc-version; Glibc <para>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.</para> <segmentedlist> <segtitle>&buildtime;</segtitle> <segtitle>&diskspace;</segtitle> <seglistitem> <seg>&glibc-fin-sbu;</seg> <seg>&glibc-fin-du;</seg> </seglistitem> </segmentedlist> </sect2> <sect2 role="installation"> <title>Installation of Glibc 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-fhs-patch; The Glibc documentation recommends building Glibc in a dedicated build directory: mkdir -v build cd build Prepare Glibc for compilation: ../configure --prefix=/usr \ --disable-werror \ --enable-kernel=&min-kernel; \ --enable-stack-protector=strong \ --with-headers=/usr/include \ libc_cv_slibdir=/lib The meaning of the options and new configure parameters: --disable-werror This option disables the -Werror option passed to GCC. This is necessary for running the test suite. --enable-stack-protector=strong This option increases system security by adding extra code to check for buffer overflows, such as stack smashing attacks. --with-headers=/usr/include This option tells the build system where to find the kernel API headers. libc_cv_slibdir=/lib This variable sets the correct library for all systems. We do not want lib64 to be used. Compile the package: make 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. case $(uname -m) in i?86) ln -sfnv $PWD/elf/ld-linux.so.2 /lib ;; x86_64) ln -sfnv $PWD/elf/ld-linux-x86-64.so.2 /lib ;; esac The symbolic link above is needed to run the tests at this stage of building in the chroot environment. It will be overwritten in the install phase below. make check You may see some test failures. The Glibc test suite is somewhat dependent on the host system. This is a list of the most common issues seen for some versions of LFS: misc/tst-ttyname is known to fail in the LFS chroot environment. The nss/tst-nss-files-hosts-multi test may fail for reasons that have not been determined. The rt/tst-cputimer{1,2,3} tests depend on the host system kernel. Kernels 4.14.91–4.14.96, 4.19.13–4.19.18, and 4.20.0–4.20.5 are known to cause these tests to fail. The math tests sometimes fail when running on systems where the CPU is not a relatively new Intel or AMD processor. Though it is a harmless message, the install stage of Glibc will complain about the absence of /etc/ld.so.conf. Prevent this warning with: touch /etc/ld.so.conf Fix the generated Makefile to skip an unneeded sanity check that fails in the LFS partial environment: sed '/test-installation/s@$(PERL)@echo not running@' -i ../Makefile 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 POSIX -f UTF-8 C.UTF-8 2> /dev/null || true 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 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 ja_JP -f SHIFT_JIS ja_JP.SIJS 2> /dev/null || true localedef -i ja_JP -f UTF-8 ja_JP.UTF-8 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 localedef -i zh_HK -f BIG5-HKSCS zh_HK.BIG5-HKSCS In addition, install the locale for your own country, language and character set. Alternatively, install all locales listed in the glibc-&glibc-version;/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-&glibc-version;/localedata/SUPPORTED file in the unlikely case you need them. 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 /etc/nsswitch.conf /etc/localtime 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 ../../tzdata&tzdata-version;.tar.gz ZONEINFO=/usr/share/zoneinfo 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 ${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 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 1.9 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 savings 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 /etc/ld.so.conf 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 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 Contents of Glibc Installed programs Installed libraries Installed directories catchsegv, gencat, getconf, getent, iconv, iconvconfig, ldconfig, ldd, lddlibc4, locale, localedef, makedb, mtrace, nscd, pcprofiledump, pldd, sln, sotruss, sprof, tzselect, xtrace, zdump, and zic ld-&glibc-version;.so, libBrokenLocale.{a,so}, libSegFault.so, libanl.{a,so}, libc.{a,so}, libc_nonshared.a, libcrypt.{a,so}, libdl.{a,so}, libg.a, libm.{a,so}, libmcheck.a, libmemusage.so, libmvec.{a,so}, libnsl.{a,so}, libnss_compat.so, libnss_dns.so, libnss_files.so, libnss_hesiod.so, libpcprofile.so, libpthread.{a,so}, libpthread_nonshared.a, libresolv.{a,so}, 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/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 catchsegv Can be used to create a stack trace when a program terminates with a segmentation fault catchsegv gencat Generates message catalogues gencat getconf Displays the system configuration values for file system specific variables getconf getent Gets entries from an administrative database getent iconv Performs character set conversion iconv iconvconfig Creates fastloading iconv module configuration files iconvconfig ldconfig Configures the dynamic linker runtime bindings ldconfig ldd Reports which shared libraries are required by each given program or shared library ldd lddlibc4 Assists ldd with object files lddlibc4 locale Prints various information about the current locale locale localedef Compiles locale specifications localedef makedb Creates a simple database from textual input makedb mtrace Reads and interprets a memory trace file and displays a summary in human-readable format mtrace nscd A daemon that provides a cache for the most common name service requests nscd pcprofiledump Dump information generated by PC profiling pcprofiledump pldd Lists dynamic shared objects used by running processes pldd sln A statically linked ln program sln sotruss Traces shared library procedure calls of a specified command sotruss sprof Reads and displays shared object profiling data sprof tzselect Asks the user about the location of the system and reports the corresponding time zone description tzselect xtrace Traces the execution of a program by printing the currently executed function xtrace zdump The time zone dumper zdump zic The time zone compiler zic ld-&glibc-version;.so The helper program for shared library executables ld-&glibc-version;.so libBrokenLocale Used internally by Glibc as a gross hack to get broken programs (e.g., some Motif applications) running. See comments in glibc-&glibc-version;/locale/broken_cur_max.c for more information libBrokenLocale libSegFault The segmentation fault signal handler, used by catchsegv libSegFault libanl An asynchronous name lookup library libanl libc The main C library libc libcrypt The cryptography library libcrypt libdl The dynamic linking interface library libdl libg Dummy library containing no functions. Previously was a runtime library for g++ libg libm The mathematical library libm libmcheck Turns on memory allocation checking when linked to libmcheck libmemusage Used by memusage to help collect information about the memory usage of a program libmemusage libnsl The network services library libnsl libnss The Name Service Switch libraries, containing functions for resolving host names, user names, group names, aliases, services, protocols, etc. libnss libpcprofile Can be preloaded to PC profile an executable libpcprofile libpthread The POSIX threads library libpthread libresolv Contains functions for creating, sending, and interpreting packets to the Internet domain name servers libresolv librt Contains functions providing most of the interfaces specified by the POSIX.1b Realtime Extension librt libthread_db Contains functions useful for building debuggers for multi-threaded programs libthread_db libutil Contains code for standard functions used in many different Unix utilities libutil