5.7. Glibc-2.21

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: 3.9 SBU
Required disk space: 670 MB

5.7.1. Installation of Glibc

In some cases, particularly LFS 7.1, the rpc headers were not installed properly. Test to see if they are installed in the host system and install if they are not:

if [ ! -r /usr/include/rpc/types.h ]; then
  su -c 'mkdir -pv /usr/include/rpc'
  su -c 'cp -v sunrpc/rpc/*.h /usr/include/rpc'
fi

Fix a regression in the package that affects 32-bit architectures:

sed -e '/ia32/s/^/1:/' \
    -e '/SSE2/s/^1://' \
    -i  sysdeps/i386/i686/multiarch/mempcpy_chk.S

The Glibc documentation recommends building Glibc outside of the source directory in a dedicated build directory:

mkdir -v ../glibc-build
cd ../glibc-build

5.7.2. 32-bit Installation

Next, prepare Glibc for 32-bit compilation:

echo slibdir=/tools/lib32 > configparms
../glibc-2.21/configure                             \
      --prefix=/tools                               \
      --host=$LFS_TGT32                             \
      --build=$(../glibc-2.21/scripts/config.guess) \
      --libdir=/tools/lib32                         \
      --disable-profile                             \
      --enable-kernel=3.4.0                         \
      --enable-add-ons                              \
      --with-headers=/tools/include                 \
      libc_cv_forced_unwind=yes                     \
      libc_cv_ctors_header=yes                      \
      libc_cv_c_cleanup=yes                         \
      CC="$LFS_TGT-gcc -m32"                        \
      CXX="$LFS_TGT-g++ -m32"

The meaning of the configure options:

echo slibdir=/tools/lib32 > configparms

Installs 32-bit system libraries to /tools/lib32.

--host=$LFS_TGT32, --build=$(../glibc-2.21/scripts/config.guess)

The combined effect of these switches is that Glibc's build system configures itself to cross-compile for 32-bit, using the cross-linker and cross-compiler in /tools.

--libdir=/tools/lib32

Installs the 32-bit library files to /tools/lib32.

--disable-profile

This builds the libraries without profiling information. Omit this option if profiling on the temporary tools is necessary.

--enable-kernel=3.4.0

This tells Glibc to compile the library with support for 3.4.0 and later Linux kernels. Workarounds for older kernels are not enabled.

--enable-add-ons;

Enables all add-on packages to ensure a successful build.

--with-headers=/tools/include

This tells Glibc to compile itself against the headers recently installed to the tools directory, so that it knows exactly what features the kernel has and can optimize itself accordingly.

libc_cv_forced_unwind=yes

The linker installed during Section 5.4, “Binutils-2.25 - Pass 1” was cross-compiled and as such cannot be used until Glibc has been installed. This means that the configure test for force-unwind support will fail, as it relies on a working linker. The libc_cv_forced_unwind=yes variable is passed in order to inform configure that force-unwind support is available without it having to run the test.

libc_cv_c_cleanup=yes

Simlarly, we pass libc_cv_c_cleanup=yes through to the configure script so that the test is skipped and C cleanup handling support is configured.

libc_cv_ctors_header=yes

Simlarly, we pass libc_cv_ctors_header=yes through to the configure script so that the test is skipped and gcc constructor support is configured.

CC="$LFS_TGT-gcc -m32", CXX="$LFS_TGT-g++ -m32"

Ensures that the GCC compiler builds 32-bit libraries.

During this stage the following warning might appear:

configure: WARNING:
*** These auxiliary programs are missing or
*** incompatible versions: msgfmt
*** some features will be disabled.
*** Check the INSTALL file for required versions.

The missing or incompatible msgfmt program is generally harmless. This msgfmt program is part of the Gettext package which the host distribution should provide.

[Note]

Note

There have been reports that this package may fail when building as a "parallel make". If this occurs, rerun the make command with a "-j1" option.

Compile the package:

make

Install the package:

make install
[Caution]

Caution

At this point, it is imperative to stop and ensure that the basic functions (compiling and linking) of the new toolchain are working as expected. To perform a sanity check, run the following commands:

echo 'main(){}' > dummy.c
$LFS_TGT-gcc -m32 dummy.c
readelf -l a.out | grep ': /tools'

If everything is working correctly, there should be no errors, and the output of the last command will be of the form:

[Requesting program interpreter: /tools/lib32/ld-linux.so.2]

If the output is not shown as above or there was no output at all, then something is wrong. Investigate and retrace the steps to find out where the problem is and correct it. This issue must be resolved before continuing on.

Once all is well, clean up the test files:

rm -v dummy.c a.out

Clean up the build directory before moving on to the next platform:

rm -fr *

5.7.3. x32 ABI Installation

Next, prepare Glibc for x32 ABI compilation:

echo slibdir=/tools/libx32 > configparms
../glibc-2.21/configure                             \
      --prefix=/tools                               \
      --host=$LFS_TGTX32                            \
      --build=$(../glibc-2.21/scripts/config.guess) \
      --libdir=/tools/libx32                        \
      --disable-profile                             \
      --enable-kernel=3.4.0                         \
      --enable-add-ons                              \
      --with-headers=/tools/include                 \
      libc_cv_forced_unwind=yes                     \
      libc_cv_ctors_header=yes                      \
      libc_cv_c_cleanup=yes                         \
      CC="$LFS_TGT-gcc -mx32"                       \
      CXX="$LFS_TGT-g++ -mx32"

The meaning of the configure options:

echo slibdir=/tools/libx32 > configparms

Installs x32 ABI system libraries to /tools/libx32.

--host=$LFS_TGTX32, --build=$(../glibc-2.21/scripts/config.guess)

The combined effect of these switches is that Glibc's build system configures itself to cross-compile for x32 ABI, using the cross-linker and cross-compiler in /tools.

--libdir=/tools/libx32

Installs the x32 ABI library files to /tools/libx32.

--disable-profile

This builds the libraries without profiling information. Omit this option if profiling on the temporary tools is necessary.

--enable-kernel=3.4.0

This tells Glibc to compile the library with support for 3.4.0 and later Linux kernels. Workarounds for older kernels are not enabled.

--enable-add-ons;

Enables all add-on packages to ensure a successful build.

--with-headers=/tools/include

This tells Glibc to compile itself against the headers recently installed to the tools directory, so that it knows exactly what features the kernel has and can optimize itself accordingly.

libc_cv_forced_unwind=yes

The linker installed during Section 5.4, “Binutils-2.25 - Pass 1” was cross-compiled and as such cannot be used until Glibc has been installed. This means that the configure test for force-unwind support will fail, as it relies on a working linker. The libc_cv_forced_unwind=yes variable is passed in order to inform configure that force-unwind support is available without it having to run the test.

libc_cv_c_cleanup=yes

Simlarly, we pass libc_cv_c_cleanup=yes through to the configure script so that the test is skipped and C cleanup handling support is configured.

libc_cv_ctors_header=yes

Simlarly, we pass libc_cv_ctors_header=yes through to the configure script so that the test is skipped and gcc constructor support is configured.

CC="$LFS_TGT-gcc -mx32", CXX="$LFS_TGT-g++ -mx32"

Ensures that the GCC compiler builds x32 ABI libraries.

During this stage the following warning might appear:

configure: WARNING:
*** These auxiliary programs are missing or
*** incompatible versions: msgfmt
*** some features will be disabled.
*** Check the INSTALL file for required versions.

The missing or incompatible msgfmt program is generally harmless. This msgfmt program is part of the Gettext package which the host distribution should provide.

[Note]

Note

There have been reports that this package may fail when building as a "parallel make". If this occurs, rerun the make command with a "-j1" option.

Compile the package:

make

This package does come with a test suite, however, it cannot be run at this time because we do not have a C++ compiler yet.

[Note]

Note

The test suite also requires locale data to be installed in order to run successfully. Locale data provides information to the system regarding such things as the date, time, and currency formats accepted and output by system utilities. If the test suites are not being run in this chapter (as per the recommendation), there is no need to install the locales now. The appropriate locales will be installed in the next chapter. To install the Glibc locales anyway, use instructions from Section 6.9, “Glibc-2.21.”

Install the package:

make install
[Caution]

Caution

At this point, it is imperative to stop and ensure that the basic functions (compiling and linking) of the new toolchain are working as expected. To perform a sanity check, run the following commands:

echo 'main(){}' > dummy.c
$LFS_TGT-gcc -mx32 dummy.c
readelf -l a.out | grep ': /tools'

If everything is working correctly, there should be no errors, and the output of the last command will be of the form:

[Requesting program interpreter: /tools/libx32/ld-linux-x32.so.2]

If the output is not shown as above or there was no output at all, then something is wrong. Investigate and retrace the steps to find out where the problem is and correct it. This issue must be resolved before continuing on.

Once all is well, clean up the test files:

rm -v dummy.c a.out

Clean up the build directory before moving on to the next platform:

rm -fr *

5.7.4. 64-bit Installation

Next, prepare Glibc for 64-bit compilation:

../glibc-2.21/configure                             \
      --prefix=/tools                               \
      --host=$LFS_TGT                               \
      --build=$(../glibc-2.21/scripts/config.guess) \
      --disable-profile                             \
      --enable-kernel=3.4.0                         \
      --with-headers=/tools/include                 \
      libc_cv_forced_unwind=yes                     \
      libc_cv_ctors_header=yes                      \
      libc_cv_c_cleanup=yes

The meaning of the configure options:

--host=$LFS_TGT, --build=$(../glibc-2.21/scripts/config.guess)

The combined effect of these switches is that Glibc's build system configures itself to cross-compile for 64-bit, using the cross-linker and cross-compiler in /tools.

--disable-profile

This builds the libraries without profiling information. Omit this option if profiling on the temporary tools is necessary.

--enable-kernel=3.4.0

This tells Glibc to compile the library with support for 3.4.0 and later Linux kernels. Workarounds for older kernels are not enabled.

--with-headers=/tools/include

This tells Glibc to compile itself against the headers recently installed to the tools directory, so that it knows exactly what features the kernel has and can optimize itself accordingly.

libc_cv_forced_unwind=yes

The linker installed during Section 5.4, “Binutils-2.25 - Pass 1” was cross-compiled and as such cannot be used until Glibc has been installed. This means that the configure test for force-unwind support will fail, as it relies on a working linker. The libc_cv_forced_unwind=yes variable is passed in order to inform configure that force-unwind support is available without it having to run the test.

libc_cv_c_cleanup=yes

Simlarly, we pass libc_cv_c_cleanup=yes through to the configure script so that the test is skipped and C cleanup handling support is configured.

libc_cv_ctors_header=yes

Simlarly, we pass libc_cv_ctors_header=yes through to the configure script so that the test is skipped and gcc constructor support is configured.

During this stage the following warning might appear:

configure: WARNING:
*** These auxiliary programs are missing or
*** incompatible versions: msgfmt
*** some features will be disabled.
*** Check the INSTALL file for required versions.

The missing or incompatible msgfmt program is generally harmless. This msgfmt program is part of the Gettext package which the host distribution should provide.

[Note]

Note

There have been reports that this package may fail when building as a "parallel make". If this occurs, rerun the make command with a "-j1" option.

Compile the package:

make

This package does come with a test suite, however, it cannot be run at this time because we do not have a C++ compiler yet.

[Note]

Note

The test suite also requires locale data to be installed in order to run successfully. Locale data provides information to the system regarding such things as the date, time, and currency formats accepted and output by system utilities. If the test suites are not being run in this chapter (as per the recommendation), there is no need to install the locales now. The appropriate locales will be installed in the next chapter. To install the Glibc locales anyway, use instructions from Section 6.9, “Glibc-2.21.”

Install the package:

make install
[Caution]

Caution

At this point, it is imperative to stop and ensure that the basic functions (compiling and linking) of the new toolchain are working as expected. To perform a sanity check, run the following commands:

echo 'main(){}' > dummy.c
$LFS_TGT-gcc dummy.c
readelf -l a.out | grep ': /tools'

If everything is working correctly, there should be no errors, and the output of the last command will be of the form:

[Requesting program interpreter: /tools/lib64/ld-linux-x86-64.so.2]

If the output is not shown as above or there was no output at all, then something is wrong. Investigate and retrace the steps to find out where the problem is and correct it. This issue must be resolved before continuing on.

Once all is well, clean up the test files:

rm -v dummy.c a.out
[Note]

Note

Building Binutils in the section after next will serve as an additional check that the toolchain has been built properly. If Binutils fails to build, it is an indication that something has gone wrong with the previous Binutils, GCC, or Glibc installations.

Details on this package are located in Section 6.9.7, “Contents of Glibc.”