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.
Some packages outside of LFS suggest installing GNU libiconv in order to translate data from one encoding to another. The project's home page (http://www.gnu.org/software/libiconv/) says “This library provides an iconv() implementation, for use on systems which don't have one, or whose implementation cannot convert from/to Unicode.” Glibc provides an iconv() implementation and can convert from/to Unicode, therefore libiconv is not required on an LFS system.
The Glibc 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 Glibc install because the Glibc autoconf tests would give false results and defeat the goal of achieving a clean build.
The glibc-libidn tarball adds support for internationalized domain names (IDN) to Glibc. Many programs that support IDN require the full libidn library, not this add-on (see http://www.linuxfromscratch.org/blfs/view/svn/general/libidn.html). Unpack the tarball from within the Glibc source directory:
tar -xvf ../glibc-libidn-2.5.tar.bz2 mv glibc-libidn-2.5 libidn
In the vi_VN.TCVN locale, bash enters an infinite loop at startup. It is unknown whether this is a bash bug or a Glibc problem. Disable installation of this locale in order to avoid the problem:
sed -i '/vi_VN.TCVN/d' localedata/SUPPORTED
When running make install, a script called test-installation.pl performs a small sanity test on our newly installed Glibc. However, because our toolchain still points to the /tools directory, the sanity test would be carried out against the wrong Glibc. We can force the script to check the Glibc we have just installed with the following:
sed -i \ 's|libs -o|libs -L/usr/lib -Wl,-dynamic-linker=/lib/ld-linux.so.2 -o|' \ scripts/test-installation.pl
The Glibc documentation recommends building Glibc outside of the source directory in a dedicated build directory:
mkdir -v ../glibc-build cd ../glibc-build
Prepare Glibc for compilation:
../glibc-2.5/configure --prefix=/usr \ --disable-profile --enable-add-ons \ --enable-kernel=2.6.0 --libexecdir=/usr/lib/glibc
The meaning of the new configure options:
This changes the location of the pt_chown program from its default of /usr/libexec to /usr/lib/glibc.
Compile the package:
In this section, the test suite for Glibc is considered critical. Do not skip it under any circumstance.
Test the results:
make -k check 2>&1 | tee glibc-check-log grep Error glibc-check-log
You will probably see an expected (ignored) failure in the posix/annexc test. In addition the Glibc test suite is somewhat dependent on the host system. This is a list of the most common issues:
The nptl/tst-clock2 and tst-attr3 tests sometimes fail. The reason is not completely understood, but indications are that a heavy system load can trigger these failures.
The math tests sometimes fail when running on systems where the CPU is not a relatively new genuine Intel or authentic AMD processor.
If you have mounted the LFS partition with the noatime option, the atime test will fail. As mentioned in Section 2.4, “Mounting the New Partition”, do not use the noatime option while building LFS.
When running on older and slower hardware or on systems under load, some tests can fail because of test timeouts being exceeded.
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:
Install the package:
The locales that can make the system respond in a different language were not installed by the above command. None of the locales are required, but if some of them are missing, testsuites of the 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/de_DE charset-independent locale definition with the /usr/share/i18n/charmaps/ISO-8859-1.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 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 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 ja_JP -f EUC-JP ja_JP
In addition, install the locale for your own country, language and character set.
Alternatively, install all locales listed in the glibc-2.5/localedata/SUPPORTED file (it includes every locale listed above and many more) at once with the following time-consuming command:
Then use the localedef command to create and install locales not listed in the glibc-2.5/localedata/SUPPORTED file in the unlikely case if you need them.
The /etc/nsswitch.conf file needs to be created because, although Glibc provides defaults when this file is missing or corrupt, the Glibc 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
One way to determine the local time zone, 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 timezones 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:
cp -v --remove-destination /usr/share/zoneinfo/<xxx> \ /etc/localtime
Replace <xxx> with the name of the time zone selected (e.g., Canada/Eastern).
The meaning of the cp option:
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.
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
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
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
Dumps information generated by PC profiling
A helper program for grantpt to set the owner, group and access permissions of a slave pseudo terminal
Generates C code to implement the Remote Procecure Call (RPC) protocol
Makes an RPC call to an RPC server
A statically linked ln program
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-2.5/locale/broken_cur_max.c for more information
The segmentation fault signal handler, used by catchsegv
An asynchronous name lookup library
Provides the portability needed in order to run certain Berkey Software Distribution (BSD) programs under Linux
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.
Contains profiling functions used to track the amount of CPU time spent in specific source code lines
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