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.
This package is known to have issues when its default optimization flags (including the -march and -mcpu options) are changed. If any environment variables that override default optimizations have been defined, such as CFLAGS and CXXFLAGS, unset them when building Glibc.
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 linuxthreads tarball contains the man pages for the threading libraries installed by Glibc. Unpack the tarball from within the Glibc source directory:
tar -xjvf /sources/glibc-linuxthreads-2.3.4.tar.bz2
Glibc has two tests which fail when the running kernel is 2.6.11.x The problem has been determined to be with the tests themselves, not with the libc nor the kernel. This patch fixes the problem:
patch -Np1 -i ../glibc-2.3.4-fix_test-1.patch
The Glibc documentation recommends building Glibc outside of the source directory in a dedicated build directory:
mkdir ../glibc-build cd ../glibc-build
Prepare Glibc for compilation:
../glibc-2.3.4/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:
The Glibc test suite is highly dependent on certain functions of the host system, in particular the kernel. In general, the Glibc test suite is always expected to pass. However, in certain circumstances, some failures are unavoidable. This is a list of the most common issues:
The math tests sometimes fail when running on systems where the CPU is not a relatively new genuine Intel or authentic AMD. Certain optimization settings are also known to be a factor here.
The gettext test sometimes fails due to host system issues. The exact reasons are not yet clear.
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, 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. Install this with:
To save time, an alternative to running the previous command (which generates and installs every locale Glibc is aware of) 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 Glibc 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 -p /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 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 the LFS and BLFS books. Because of the various problems that arise due to application programmers making assumptions that break in such locales, LFS 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 LFS developers not to support such complex locales. 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.
Build the linuxthreads man pages, which are a great reference on the threading API (applicable to NPTL as well):
make -C ../glibc-2.3.4/linuxthreads/man
Install these pages:
make -C ../glibc-2.3.4/linuxthreads/man install
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
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., EST5EDT or Canada/Eastern). Then create the /etc/localtime file by running:
cp --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:
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
Tells the compiler to enable or disable the use of POSIX locales for built-in operations
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
Checks whether or not secure mode is necessary for NIS+ lookup
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 by programs, such as Mozilla, to solve broken locales
The segmentation fault signal handler
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
The cryptography library
The dynamic linking interface library
A runtime library for g++
The Institute of Electrical and Electronic Engineers (IEEE) floating point library
The mathematical library
Contains code run at boot
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