10.7. Glibc-2.7
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.
10.7.1. Installation of Glibc
![[Note]](../images/note.png)
Note
Some packages outside of CLFS 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 a
CLFS 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 following patches merges all updates from the 2.7 Branch from
the Glibc developers:
patch -Np1 -i ../glibc-2.7-branch_update-1A.patch
The following patch ensures that memcpy_chk, mempcpy_chk, and
memset_chk are defined for i586.
patch -Np1 -i ../glibc-2.7-i586_chk-2.patch
The following patch fixes an issue that can cause localdef to segfault:
patch -Np1 -i ../glibc-2.7-localedef_segfault-1.patch
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:
CFLAGS="-march=$(cut -d- -f1 <<< $MACHTYPE) \
-mtune=generic -g -O2" ../glibc-2.7/configure --prefix=/usr \
--disable-profile --enable-add-ons --enable-kernel=2.6.0 \
--libexecdir=/usr/lib/glibc
The meaning of the new configure option:
-
--libexecdir=/usr/lib/glibc
-
This changes the location of the pt_chown program from its
default of /usr/libexec to
/usr/lib/glibc.
Compile the package:
make
![[Important]](../images/important.png)
Important
The test suite for Glibc is considered critical. Do not skip it
under any circumstance.
Test the results:
make -k check >glibc-check-log 2>&1 ; grep Error glibc-check-log
The Glibc test suite is highly dependent on certain functions of
the host system, in particular the kernel. The posix/annexc test
normally fails and you should see Error 1
(ignored) in the output. Apart from this, the Glibc test
suite is always expected to pass. However, in certain
circumstances, some failures are unavoidable. If a test fails
because of a missing program (or missing symbolic link), or a
segfault, you will see an error code greater than 127 and the
details will be in the log. More commonly, tests will fail with
Error 2 - for these, the contents of
the corresponding .out file, e.g.
posix/annexc.out may be informative.
Here is a list of the most common issues:
-
The math tests, at
least on i686, fail in the test-double and test-idouble tests with gcc-4.2.4
. These two failures in the math tests appear to be harmless.
The math tests may also fail 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.
-
If you have mounted the CLFS 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 CLFS.
-
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:
touch /etc/ld.so.conf
Install the package:
make install
10.7.2.
Internationalization
The locales that can make the system respond in a different
language were not installed by the above command. Install them
with:
make localedata/install-locales
To save time, an alternative to running the previous command (which
generates and installs every locale listed in the
glibc-2.7/localedata/SUPPORTED file) 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 -pv /usr/lib/locale
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 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 CLFS and
BLFS books. Because of the various problems that arise due to
application programmers making assumptions that break in such
locales, CLFS 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 CLFS developers not to
support such complex locales at this time. 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.
10.7.3. Configuring Glibc
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:
tzselect
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 -v --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:
-
--remove-destination
-
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.
10.7.4. Configuring The Dynamic
Loader
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
10.7.5. Contents
of Glibc
Installed programs:
catchsegv, gencat, getconf, getent,
iconv, iconvconfig, ldconfig, ldd, lddlibc4, locale, localedef,
mtrace, nscd, pcprofiledump, pt_chown, rpcgen, rpcinfo, sln,
sprof, tzselect, xtrace, zdump, and zic
Installed libraries:
ld.so, libBrokenLocale.[a,so],
libSegFault.so, libanl.[a,so], libbsd-compat.a, libc.[a,so],
libcrypt.[a,so], libdl.[a,so], libg.a, libieee.a, libm.[a,so],
libmcheck.a, libmemusage.so, libnsl.a, libnss_compat.so,
libnss_dns.so, libnss_files.so, libnss_hesiod.so,
libnss_nis.so, libnss_nisplus.so, libpcprofile.so,
libpthread.[a,so], libresolv.[a,so], librpcsvc.a, librt.[a,so],
libthread_db.so, and libutil.[a,so]
Short Descriptions
|
catchsegv
|
Can be used to create a stack trace when a program
terminates with a segmentation fault
|
|
gencat
|
Generates message catalogues
|
|
getconf
|
Displays the system configuration values for file system
specific variables
|
|
getent
|
Gets entries from an administrative database
|
|
iconv
|
Performs character set conversion
|
|
iconvconfig
|
Creates fastloading iconv module
configuration files
|
|
ldconfig
|
Configures the dynamic linker runtime bindings
|
|
ldd
|
Reports which shared libraries are required by each given
program or shared library
|
|
lddlibc4
|
Assists ldd
with object files
|
|
locale
|
Tells the compiler to enable or disable the use of POSIX
locales for built-in operations
|
|
localedef
|
Compiles locale specifications
|
|
mtrace
|
Reads and interprets a memory trace file and displays a
summary in human-readable format
|
|
nscd
|
A daemon that provides a cache for the most common name
service requests
|
|
pcprofiledump
|
Dumps information generated by PC profiling
|
|
pt_chown
|
A helper program for grantpt to set the
owner, group and access permissions of a slave pseudo
terminal
|
|
rpcgen
|
Generates C code to implement the Remote Procecure Call
(RPC) protocol
|
|
rpcinfo
|
Makes an RPC call to an RPC server
|
|
sln
|
A statically linked program that creates symbolic links
|
|
sprof
|
Reads and displays shared object profiling data
|
|
tzselect
|
Asks the user about the location of the system and
reports the corresponding time zone description
|
|
xtrace
|
Traces the execution of a program by printing the
currently executed function
|
|
zdump
|
The time zone dumper
|
|
zic
|
The time zone compiler
|
|
ld.so
|
The helper program for shared library executables
|
|
libBrokenLocale
|
Used by programs, such as Mozilla, to solve broken
locales
|
|
libSegFault
|
The segmentation fault signal handler
|
|
libanl
|
An asynchronous name lookup library
|
|
libbsd-compat
|
Provides the portability needed in order to run certain
Berkey Software Distribution (BSD) programs under Linux
|
|
libc
|
The main C library
|
|
libcrypt
|
The cryptography library
|
|
libdl
|
The dynamic linking interface library
|
|
libg
|
A runtime library for g++
|
|
libieee
|
The Institute of Electrical and Electronic Engineers
(IEEE) floating point library
|
|
libm
|
The mathematical library
|
|
libmcheck
|
Contains code run at boot
|
|
libmemusage
|
Used by memusage (included in
Glibc, but not built in a base CLFS system as it has
additional dependencies) to help collect information
about the memory usage of a program
|
|
libnsl
|
The network services library
|
|
libnss
|
The Name Service Switch libraries, containing functions
for resolving host names, user names, group names,
aliases, services, protocols, etc.
|
|
libpcprofile
|
Contains profiling functions used to track the amount of
CPU time spent in specific source code lines
|
|
libpthread
|
The POSIX threads library
|
|
libresolv
|
Contains functions for creating, sending, and
interpreting packets to the Internet domain name servers
|
|
librpcsvc
|
Contains functions providing miscellaneous RPC services
|
|
librt
|
Contains functions providing most of the interfaces
specified by the POSIX.1b Realtime Extension
|
|
libthread_db
|
Contains functions useful for building debuggers for
multi-threaded programs
|
|
libutil
|
Contains code for “standard” functions used in many
different Unix utilities
|