e69d994a63
Some Linux distributions are experimenting with a new, separately maintained and hopefully more agile implementation of the crypt API. To facilitate this, add a configure option which disables glibc's embedded libcrypt. When this option is given, libcrypt.* and crypt.h will not be built nor installed.
602 lines
29 KiB
Plaintext
602 lines
29 KiB
Plaintext
Installing the GNU C Library
|
|
****************************
|
|
|
|
Before you do anything else, you should read the FAQ at
|
|
<https://sourceware.org/glibc/wiki/FAQ>. It answers common questions
|
|
and describes problems you may experience with compilation and
|
|
installation.
|
|
|
|
You will need recent versions of several GNU tools: definitely GCC
|
|
and GNU Make, and possibly others. *Note Tools for Compilation::,
|
|
below.
|
|
|
|
Configuring and compiling the GNU C Library
|
|
===========================================
|
|
|
|
The GNU C Library cannot be compiled in the source directory. You must
|
|
build it in a separate build directory. For example, if you have
|
|
unpacked the GNU C Library sources in '/src/gnu/glibc-VERSION', create a
|
|
directory '/src/gnu/glibc-build' to put the object files in. This
|
|
allows removing the whole build directory in case an error occurs, which
|
|
is the safest way to get a fresh start and should always be done.
|
|
|
|
From your object directory, run the shell script 'configure' located
|
|
at the top level of the source tree. In the scenario above, you'd type
|
|
|
|
$ ../glibc-VERSION/configure ARGS...
|
|
|
|
Please note that even though you're building in a separate build
|
|
directory, the compilation may need to create or modify files and
|
|
directories in the source directory.
|
|
|
|
'configure' takes many options, but the only one that is usually
|
|
mandatory is '--prefix'. This option tells 'configure' where you want
|
|
the GNU C Library installed. This defaults to '/usr/local', but the
|
|
normal setting to install as the standard system library is
|
|
'--prefix=/usr' for GNU/Linux systems and '--prefix=' (an empty prefix)
|
|
for GNU/Hurd systems.
|
|
|
|
It may also be useful to pass 'CC=COMPILER' and 'CFLAGS=FLAGS'
|
|
arguments to 'configure'. 'CC' selects the C compiler that will be
|
|
used, and 'CFLAGS' sets optimization options for the compiler. Any
|
|
compiler options required for all compilations, such as options
|
|
selecting an ABI or a processor for which to generate code, should be
|
|
included in 'CC'. Options that may be overridden by the GNU C Library
|
|
build system for particular files, such as for optimization and
|
|
debugging, should go in 'CFLAGS'. The default value of 'CFLAGS' is '-g
|
|
-O2', and the GNU C Library cannot be compiled without optimization, so
|
|
if 'CFLAGS' is specified it must enable optimization. For example:
|
|
|
|
$ ../glibc-VERSION/configure CC="gcc -m32" CFLAGS="-O3"
|
|
|
|
The following list describes all of the available options for
|
|
'configure':
|
|
|
|
'--prefix=DIRECTORY'
|
|
Install machine-independent data files in subdirectories of
|
|
'DIRECTORY'. The default is to install in '/usr/local'.
|
|
|
|
'--exec-prefix=DIRECTORY'
|
|
Install the library and other machine-dependent files in
|
|
subdirectories of 'DIRECTORY'. The default is to the '--prefix'
|
|
directory if that option is specified, or '/usr/local' otherwise.
|
|
|
|
'--with-headers=DIRECTORY'
|
|
Look for kernel header files in DIRECTORY, not '/usr/include'. The
|
|
GNU C Library needs information from the kernel's header files
|
|
describing the interface to the kernel. The GNU C Library will
|
|
normally look in '/usr/include' for them, but if you specify this
|
|
option, it will look in DIRECTORY instead.
|
|
|
|
This option is primarily of use on a system where the headers in
|
|
'/usr/include' come from an older version of the GNU C Library.
|
|
Conflicts can occasionally happen in this case. You can also use
|
|
this option if you want to compile the GNU C Library with a newer
|
|
set of kernel headers than the ones found in '/usr/include'.
|
|
|
|
'--enable-kernel=VERSION'
|
|
This option is currently only useful on GNU/Linux systems. The
|
|
VERSION parameter should have the form X.Y.Z and describes the
|
|
smallest version of the Linux kernel the generated library is
|
|
expected to support. The higher the VERSION number is, the less
|
|
compatibility code is added, and the faster the code gets.
|
|
|
|
'--with-binutils=DIRECTORY'
|
|
Use the binutils (assembler and linker) in 'DIRECTORY', not the
|
|
ones the C compiler would default to. You can use this option if
|
|
the default binutils on your system cannot deal with all the
|
|
constructs in the GNU C Library. In that case, 'configure' will
|
|
detect the problem and suppress these constructs, so that the
|
|
library will still be usable, but functionality may be lost--for
|
|
example, you can't build a shared libc with old binutils.
|
|
|
|
'--disable-shared'
|
|
Don't build shared libraries even if it is possible. Not all
|
|
systems support shared libraries; you need ELF support and
|
|
(currently) the GNU linker.
|
|
|
|
'--enable-static-pie'
|
|
Enable static position independent executable (static PIE) support.
|
|
Static PIE is similar to static executable, but can be loaded at
|
|
any address without help from a dynamic linker. All static
|
|
programs as well as static tests are built as static PIE, except
|
|
for those marked with no-pie. The resulting glibc can be used with
|
|
the GCC option, -static-pie, which is available with GCC 8 or
|
|
above, to create static PIE. This option also implies that glibc
|
|
programs and tests are created as dynamic position independent
|
|
executables (PIE) by default.
|
|
|
|
'--disable-profile'
|
|
Don't build libraries with profiling information. You may want to
|
|
use this option if you don't plan to do profiling.
|
|
|
|
'--enable-static-nss'
|
|
Compile static versions of the NSS (Name Service Switch) libraries.
|
|
This is not recommended because it defeats the purpose of NSS; a
|
|
program linked statically with the NSS libraries cannot be
|
|
dynamically reconfigured to use a different name database.
|
|
|
|
'--enable-hardcoded-path-in-tests'
|
|
By default, dynamic tests are linked to run with the installed C
|
|
library. This option hardcodes the newly built C library path in
|
|
dynamic tests so that they can be invoked directly.
|
|
|
|
'--disable-timezone-tools'
|
|
By default, timezone related utilities ('zic', 'zdump', and
|
|
'tzselect') are installed with the GNU C Library. If you are
|
|
building these independently (e.g. by using the 'tzcode' package),
|
|
then this option will allow disabling the install of these.
|
|
|
|
Note that you need to make sure the external tools are kept in sync
|
|
with the versions that the GNU C Library expects as the data
|
|
formats may change over time. Consult the 'timezone' subdirectory
|
|
for more details.
|
|
|
|
'--enable-stack-protector'
|
|
'--enable-stack-protector=strong'
|
|
'--enable-stack-protector=all'
|
|
Compile the C library and all other parts of the glibc package
|
|
(including the threading and math libraries, NSS modules, and
|
|
transliteration modules) using the GCC '-fstack-protector',
|
|
'-fstack-protector-strong' or '-fstack-protector-all' options to
|
|
detect stack overruns. Only the dynamic linker and a small number
|
|
of routines called directly from assembler are excluded from this
|
|
protection.
|
|
|
|
'--enable-bind-now'
|
|
Disable lazy binding for installed shared objects. This provides
|
|
additional security hardening because it enables full RELRO and a
|
|
read-only global offset table (GOT), at the cost of slightly
|
|
increased program load times.
|
|
|
|
'--enable-pt_chown'
|
|
The file 'pt_chown' is a helper binary for 'grantpt' (*note
|
|
Pseudo-Terminals: Allocation.) that is installed setuid root to fix
|
|
up pseudo-terminal ownership. It is not built by default because
|
|
systems using the Linux kernel are commonly built with the 'devpts'
|
|
filesystem enabled and mounted at '/dev/pts', which manages
|
|
pseudo-terminal ownership automatically. By using
|
|
'--enable-pt_chown', you may build 'pt_chown' and install it setuid
|
|
and owned by 'root'. The use of 'pt_chown' introduces additional
|
|
security risks to the system and you should enable it only if you
|
|
understand and accept those risks.
|
|
|
|
'--disable-werror'
|
|
By default, the GNU C Library is built with '-Werror'. If you wish
|
|
to build without this option (for example, if building with a newer
|
|
version of GCC than this version of the GNU C Library was tested
|
|
with, so new warnings cause the build with '-Werror' to fail), you
|
|
can configure with '--disable-werror'.
|
|
|
|
'--disable-mathvec'
|
|
By default for x86_64, the GNU C Library is built with the vector
|
|
math library. Use this option to disable the vector math library.
|
|
|
|
'--enable-tunables'
|
|
Tunables support allows additional library parameters to be
|
|
customized at runtime. This feature is enabled by default. This
|
|
option can take the following values:
|
|
|
|
'yes'
|
|
This is the default if no option is passed to configure. This
|
|
enables tunables and selects the default frontend (currently
|
|
'valstring').
|
|
|
|
'no'
|
|
This option disables tunables.
|
|
|
|
'valstring'
|
|
This enables tunables and selects the 'valstring' frontend for
|
|
tunables. This frontend allows users to specify tunables as a
|
|
colon-separated list in a single environment variable
|
|
'GLIBC_TUNABLES'.
|
|
|
|
'--enable-obsolete-nsl'
|
|
By default, libnsl is only built as shared library for backward
|
|
compatibility and the NSS modules libnss_compat, libnss_nis and
|
|
libnss_nisplus are not built at all. Use this option to enable
|
|
libnsl with all depending NSS modules and header files.
|
|
|
|
'--disable-crypt'
|
|
Do not install the passphrase-hashing library 'libcrypt' or the
|
|
header file 'crypt.h'. 'unistd.h' will still declare the function
|
|
'crypt'. Using this option does not change the set of programs
|
|
that may need to be linked with '-lcrypt'; it only means that the
|
|
GNU C Library will not provide that library.
|
|
|
|
This option is for hackers and distributions experimenting with
|
|
independently-maintained implementations of libcrypt. It may
|
|
become the default in a future release.
|
|
|
|
'--disable-experimental-malloc'
|
|
By default, a per-thread cache is enabled in 'malloc'. While this
|
|
cache can be disabled on a per-application basis using tunables
|
|
(set glibc.malloc.tcache_count to zero), this option can be used to
|
|
remove it from the build completely.
|
|
|
|
'--build=BUILD-SYSTEM'
|
|
'--host=HOST-SYSTEM'
|
|
These options are for cross-compiling. If you specify both options
|
|
and BUILD-SYSTEM is different from HOST-SYSTEM, 'configure' will
|
|
prepare to cross-compile the GNU C Library from BUILD-SYSTEM to be
|
|
used on HOST-SYSTEM. You'll probably need the '--with-headers'
|
|
option too, and you may have to override CONFIGURE's selection of
|
|
the compiler and/or binutils.
|
|
|
|
If you only specify '--host', 'configure' will prepare for a native
|
|
compile but use what you specify instead of guessing what your
|
|
system is. This is most useful to change the CPU submodel. For
|
|
example, if 'configure' guesses your machine as 'i686-pc-linux-gnu'
|
|
but you want to compile a library for 586es, give
|
|
'--host=i586-pc-linux-gnu' or just '--host=i586-linux' and add the
|
|
appropriate compiler flags ('-mcpu=i586' will do the trick) to
|
|
'CC'.
|
|
|
|
If you specify just '--build', 'configure' will get confused.
|
|
|
|
'--with-pkgversion=VERSION'
|
|
Specify a description, possibly including a build number or build
|
|
date, of the binaries being built, to be included in '--version'
|
|
output from programs installed with the GNU C Library. For
|
|
example, '--with-pkgversion='FooBar GNU/Linux glibc build 123''.
|
|
The default value is 'GNU libc'.
|
|
|
|
'--with-bugurl=URL'
|
|
Specify the URL that users should visit if they wish to report a
|
|
bug, to be included in '--help' output from programs installed with
|
|
the GNU C Library. The default value refers to the main
|
|
bug-reporting information for the GNU C Library.
|
|
|
|
To build the library and related programs, type 'make'. This will
|
|
produce a lot of output, some of which may look like errors from 'make'
|
|
but aren't. Look for error messages from 'make' containing '***'.
|
|
Those indicate that something is seriously wrong.
|
|
|
|
The compilation process can take a long time, depending on the
|
|
configuration and the speed of your machine. Some complex modules may
|
|
take a very long time to compile, as much as several minutes on slower
|
|
machines. Do not panic if the compiler appears to hang.
|
|
|
|
If you want to run a parallel make, simply pass the '-j' option with
|
|
an appropriate numeric parameter to 'make'. You need a recent GNU
|
|
'make' version, though.
|
|
|
|
To build and run test programs which exercise some of the library
|
|
facilities, type 'make check'. If it does not complete successfully, do
|
|
not use the built library, and report a bug after verifying that the
|
|
problem is not already known. *Note Reporting Bugs::, for instructions
|
|
on reporting bugs. Note that some of the tests assume they are not
|
|
being run by 'root'. We recommend you compile and test the GNU C
|
|
Library as an unprivileged user.
|
|
|
|
Before reporting bugs make sure there is no problem with your system.
|
|
The tests (and later installation) use some pre-existing files of the
|
|
system such as '/etc/passwd', '/etc/nsswitch.conf' and others. These
|
|
files must all contain correct and sensible content.
|
|
|
|
Normally, 'make check' will run all the tests before reporting all
|
|
problems found and exiting with error status if any problems occurred.
|
|
You can specify 'stop-on-test-failure=y' when running 'make check' to
|
|
make the test run stop and exit with an error status immediately when a
|
|
failure occurs.
|
|
|
|
The GNU C Library pretty printers come with their own set of scripts
|
|
for testing, which run together with the rest of the testsuite through
|
|
'make check'. These scripts require the following tools to run
|
|
successfully:
|
|
|
|
* Python 2.7.6/3.4.3 or later
|
|
|
|
Python is required for running the printers' test scripts.
|
|
|
|
* PExpect 4.0
|
|
|
|
The printer tests drive GDB through test programs and compare its
|
|
output to the printers'. PExpect is used to capture the output of
|
|
GDB, and should be compatible with the Python version in your
|
|
system.
|
|
|
|
* GDB 7.8 or later with support for Python 2.7.6/3.4.3 or later
|
|
|
|
GDB itself needs to be configured with Python support in order to
|
|
use the pretty printers. Notice that your system having Python
|
|
available doesn't imply that GDB supports it, nor that your
|
|
system's Python and GDB's have the same version.
|
|
|
|
If these tools are absent, the printer tests will report themselves as
|
|
'UNSUPPORTED'. Notice that some of the printer tests require the GNU C
|
|
Library to be compiled with debugging symbols.
|
|
|
|
To format the 'GNU C Library Reference Manual' for printing, type
|
|
'make dvi'. You need a working TeX installation to do this. The
|
|
distribution builds the on-line formatted version of the manual, as Info
|
|
files, as part of the build process. You can build them manually with
|
|
'make info'.
|
|
|
|
The library has a number of special-purpose configuration parameters
|
|
which you can find in 'Makeconfig'. These can be overwritten with the
|
|
file 'configparms'. To change them, create a 'configparms' in your
|
|
build directory and add values as appropriate for your system. The file
|
|
is included and parsed by 'make' and has to follow the conventions for
|
|
makefiles.
|
|
|
|
It is easy to configure the GNU C Library for cross-compilation by
|
|
setting a few variables in 'configparms'. Set 'CC' to the
|
|
cross-compiler for the target you configured the library for; it is
|
|
important to use this same 'CC' value when running 'configure', like
|
|
this: 'configure TARGET CC=TARGET-gcc'. Set 'BUILD_CC' to the compiler
|
|
to use for programs run on the build system as part of compiling the
|
|
library. You may need to set 'AR' to cross-compiling versions of 'ar'
|
|
if the native tools are not configured to work with object files for the
|
|
target you configured for. When cross-compiling the GNU C Library, it
|
|
may be tested using 'make check
|
|
test-wrapper="SRCDIR/scripts/cross-test-ssh.sh HOSTNAME"', where SRCDIR
|
|
is the absolute directory name for the main source directory and
|
|
HOSTNAME is the host name of a system that can run the newly built
|
|
binaries of the GNU C Library. The source and build directories must be
|
|
visible at the same locations on both the build system and HOSTNAME.
|
|
|
|
In general, when testing the GNU C Library, 'test-wrapper' may be set
|
|
to the name and arguments of any program to run newly built binaries.
|
|
This program must preserve the arguments to the binary being run, its
|
|
working directory and the standard input, output and error file
|
|
descriptors. If 'TEST-WRAPPER env' will not work to run a program with
|
|
environment variables set, then 'test-wrapper-env' must be set to a
|
|
program that runs a newly built program with environment variable
|
|
assignments in effect, those assignments being specified as 'VAR=VALUE'
|
|
before the name of the program to be run. If multiple assignments to
|
|
the same variable are specified, the last assignment specified must take
|
|
precedence. Similarly, if 'TEST-WRAPPER env -i' will not work to run a
|
|
program with an environment completely empty of variables except those
|
|
directly assigned, then 'test-wrapper-env-only' must be set; its use has
|
|
the same syntax as 'test-wrapper-env', the only difference in its
|
|
semantics being starting with an empty set of environment variables
|
|
rather than the ambient set.
|
|
|
|
Installing the C Library
|
|
========================
|
|
|
|
To install the library and its header files, and the Info files of the
|
|
manual, type 'make install'. This will build things, if necessary,
|
|
before installing them; however, you should still compile everything
|
|
first. If you are installing the GNU C Library as your primary C
|
|
library, we recommend that you shut the system down to single-user mode
|
|
first, and reboot afterward. This minimizes the risk of breaking things
|
|
when the library changes out from underneath.
|
|
|
|
'make install' will do the entire job of upgrading from a previous
|
|
installation of the GNU C Library version 2.x. There may sometimes be
|
|
headers left behind from the previous installation, but those are
|
|
generally harmless. If you want to avoid leaving headers behind you can
|
|
do things in the following order.
|
|
|
|
You must first build the library ('make'), optionally check it ('make
|
|
check'), switch the include directories and then install ('make
|
|
install'). The steps must be done in this order. Not moving the
|
|
directory before install will result in an unusable mixture of header
|
|
files from both libraries, but configuring, building, and checking the
|
|
library requires the ability to compile and run programs against the old
|
|
library. The new '/usr/include', after switching the include
|
|
directories and before installing the library should contain the Linux
|
|
headers, but nothing else. If you do this, you will need to restore any
|
|
headers from libraries other than the GNU C Library yourself after
|
|
installing the library.
|
|
|
|
You can install the GNU C Library somewhere other than where you
|
|
configured it to go by setting the 'DESTDIR' GNU standard make variable
|
|
on the command line for 'make install'. The value of this variable is
|
|
prepended to all the paths for installation. This is useful when
|
|
setting up a chroot environment or preparing a binary distribution. The
|
|
directory should be specified with an absolute file name. Installing
|
|
with the 'prefix' and 'exec_prefix' GNU standard make variables set is
|
|
not supported.
|
|
|
|
The GNU C Library includes a daemon called 'nscd', which you may or
|
|
may not want to run. 'nscd' caches name service lookups; it can
|
|
dramatically improve performance with NIS+, and may help with DNS as
|
|
well.
|
|
|
|
One auxiliary program, '/usr/libexec/pt_chown', is installed setuid
|
|
'root' if the '--enable-pt_chown' configuration option is used. This
|
|
program is invoked by the 'grantpt' function; it sets the permissions on
|
|
a pseudoterminal so it can be used by the calling process. If you are
|
|
using a Linux kernel with the 'devpts' filesystem enabled and mounted at
|
|
'/dev/pts', you don't need this program.
|
|
|
|
After installation you might want to configure the timezone and
|
|
locale installation of your system. The GNU C Library comes with a
|
|
locale database which gets configured with 'localedef'. For example, to
|
|
set up a German locale with name 'de_DE', simply issue the command
|
|
'localedef -i de_DE -f ISO-8859-1 de_DE'. To configure all locales that
|
|
are supported by the GNU C Library, you can issue from your build
|
|
directory the command 'make localedata/install-locales'.
|
|
|
|
To configure the locally used timezone, set the 'TZ' environment
|
|
variable. The script 'tzselect' helps you to select the right value.
|
|
As an example, for Germany, 'tzselect' would tell you to use
|
|
'TZ='Europe/Berlin''. For a system wide installation (the given paths
|
|
are for an installation with '--prefix=/usr'), link the timezone file
|
|
which is in '/usr/share/zoneinfo' to the file '/etc/localtime'. For
|
|
Germany, you might execute 'ln -s /usr/share/zoneinfo/Europe/Berlin
|
|
/etc/localtime'.
|
|
|
|
Recommended Tools for Compilation
|
|
=================================
|
|
|
|
We recommend installing the following GNU tools before attempting to
|
|
build the GNU C Library:
|
|
|
|
* GNU 'make' 3.79 or newer
|
|
|
|
You need the latest version of GNU 'make'. Modifying the GNU C
|
|
Library to work with other 'make' programs would be so difficult
|
|
that we recommend you port GNU 'make' instead. *Really.* We
|
|
recommend GNU 'make' version 3.79. All earlier versions have
|
|
severe bugs or lack features.
|
|
|
|
* GCC 4.9 or newer
|
|
|
|
GCC 4.9 or higher is required. In general it is recommended to use
|
|
the newest version of the compiler that is known to work for
|
|
building the GNU C Library, as newer compilers usually produce
|
|
better code. As of release time, GCC 7.3 is the newest compiler
|
|
verified to work to build the GNU C Library.
|
|
|
|
For PowerPC 64-bits little-endian (powerpc64le), GCC 6.2 or higher
|
|
is required. This compiler version is the first to provide the
|
|
features required for building the GNU C Library with support for
|
|
'_Float128'.
|
|
|
|
For multi-arch support it is recommended to use a GCC which has
|
|
been built with support for GNU indirect functions. This ensures
|
|
that correct debugging information is generated for functions
|
|
selected by IFUNC resolvers. This support can either be enabled by
|
|
configuring GCC with '--enable-gnu-indirect-function', or by
|
|
enabling it by default by setting 'default_gnu_indirect_function'
|
|
variable for a particular architecture in the GCC source file
|
|
'gcc/config.gcc'.
|
|
|
|
You can use whatever compiler you like to compile programs that use
|
|
the GNU C Library.
|
|
|
|
Check the FAQ for any special compiler issues on particular
|
|
platforms.
|
|
|
|
* GNU 'binutils' 2.25 or later
|
|
|
|
You must use GNU 'binutils' (as and ld) to build the GNU C Library.
|
|
No other assembler or linker has the necessary functionality at the
|
|
moment. As of release time, GNU 'binutils' 2.29.1 is the newest
|
|
verified to work to build the GNU C Library.
|
|
|
|
* GNU 'texinfo' 4.7 or later
|
|
|
|
To correctly translate and install the Texinfo documentation you
|
|
need this version of the 'texinfo' package. Earlier versions do
|
|
not understand all the tags used in the document, and the
|
|
installation mechanism for the info files is not present or works
|
|
differently. As of release time, 'texinfo' 6.5 is the newest
|
|
verified to work to build the GNU C Library.
|
|
|
|
* GNU 'awk' 3.1.2, or higher
|
|
|
|
'awk' is used in several places to generate files. Some 'gawk'
|
|
extensions are used, including the 'asorti' function, which was
|
|
introduced in version 3.1.2 of 'gawk'. As of release time, 'gawk'
|
|
version 4.2.0 is the newest verified to work to build the GNU C
|
|
Library.
|
|
|
|
* GNU 'bison' 2.7 or later
|
|
|
|
'bison' is used to generate the 'yacc' parser code in the 'intl'
|
|
subdirectory. As of release time, 'bison' version 3.0.4 is the
|
|
newest verified to work to build the GNU C Library.
|
|
|
|
* Perl 5
|
|
|
|
Perl is not required, but it is used if present to test the
|
|
installation. We may decide to use it elsewhere in the future.
|
|
|
|
* GNU 'sed' 3.02 or newer
|
|
|
|
'Sed' is used in several places to generate files. Most scripts
|
|
work with any version of 'sed'. As of release time, 'sed' version
|
|
4.4 is the newest verified to work to build the GNU C Library.
|
|
|
|
If you change any of the 'configure.ac' files you will also need
|
|
|
|
* GNU 'autoconf' 2.69 (exactly)
|
|
|
|
and if you change any of the message translation files you will need
|
|
|
|
* GNU 'gettext' 0.10.36 or later
|
|
|
|
You may also need these packages if you upgrade your source tree using
|
|
patches, although we try to avoid this.
|
|
|
|
Specific advice for GNU/Linux systems
|
|
=====================================
|
|
|
|
If you are installing the GNU C Library on GNU/Linux systems, you need
|
|
to have the header files from a 3.2 or newer kernel around for
|
|
reference. (For the ia64 architecture, you need version 3.2.18 or newer
|
|
because this is the first version with support for the 'accept4' system
|
|
call.) These headers must be installed using 'make headers_install';
|
|
the headers present in the kernel source directory are not suitable for
|
|
direct use by the GNU C Library. You do not need to use that kernel,
|
|
just have its headers installed where the GNU C Library can access them,
|
|
referred to here as INSTALL-DIRECTORY. The easiest way to do this is to
|
|
unpack it in a directory such as '/usr/src/linux-VERSION'. In that
|
|
directory, run 'make headers_install
|
|
INSTALL_HDR_PATH=INSTALL-DIRECTORY'. Finally, configure the GNU C
|
|
Library with the option '--with-headers=INSTALL-DIRECTORY/include'. Use
|
|
the most recent kernel you can get your hands on. (If you are
|
|
cross-compiling the GNU C Library, you need to specify
|
|
'ARCH=ARCHITECTURE' in the 'make headers_install' command, where
|
|
ARCHITECTURE is the architecture name used by the Linux kernel, such as
|
|
'x86' or 'powerpc'.)
|
|
|
|
After installing the GNU C Library, you may need to remove or rename
|
|
directories such as '/usr/include/linux' and '/usr/include/asm', and
|
|
replace them with copies of directories such as 'linux' and 'asm' from
|
|
'INSTALL-DIRECTORY/include'. All directories present in
|
|
'INSTALL-DIRECTORY/include' should be copied, except that the GNU C
|
|
Library provides its own version of '/usr/include/scsi'; the files
|
|
provided by the kernel should be copied without replacing those provided
|
|
by the GNU C Library. The 'linux', 'asm' and 'asm-generic' directories
|
|
are required to compile programs using the GNU C Library; the other
|
|
directories describe interfaces to the kernel but are not required if
|
|
not compiling programs using those interfaces. You do not need to copy
|
|
kernel headers if you did not specify an alternate kernel header source
|
|
using '--with-headers'.
|
|
|
|
The Filesystem Hierarchy Standard for GNU/Linux systems expects some
|
|
components of the GNU C Library installation to be in '/lib' and some in
|
|
'/usr/lib'. This is handled automatically if you configure the GNU C
|
|
Library with '--prefix=/usr'. If you set some other prefix or allow it
|
|
to default to '/usr/local', then all the components are installed there.
|
|
|
|
Reporting Bugs
|
|
==============
|
|
|
|
There are probably bugs in the GNU C Library. There are certainly
|
|
errors and omissions in this manual. If you report them, they will get
|
|
fixed. If you don't, no one will ever know about them and they will
|
|
remain unfixed for all eternity, if not longer.
|
|
|
|
It is a good idea to verify that the problem has not already been
|
|
reported. Bugs are documented in two places: The file 'BUGS' describes
|
|
a number of well known bugs and the central GNU C Library bug tracking
|
|
system has a WWW interface at <https://sourceware.org/bugzilla/>. The
|
|
WWW interface gives you access to open and closed reports. A closed
|
|
report normally includes a patch or a hint on solving the problem.
|
|
|
|
To report a bug, first you must find it. With any luck, this will be
|
|
the hard part. Once you've found a bug, make sure it's really a bug. A
|
|
good way to do this is to see if the GNU C Library behaves the same way
|
|
some other C library does. If so, probably you are wrong and the
|
|
libraries are right (but not necessarily). If not, one of the libraries
|
|
is probably wrong. It might not be the GNU C Library. Many historical
|
|
Unix C libraries permit things that we don't, such as closing a file
|
|
twice.
|
|
|
|
If you think you have found some way in which the GNU C Library does
|
|
not conform to the ISO and POSIX standards (*note Standards and
|
|
Portability::), that is definitely a bug. Report it!
|
|
|
|
Once you're sure you've found a bug, try to narrow it down to the
|
|
smallest test case that reproduces the problem. In the case of a C
|
|
library, you really only need to narrow it down to one library function
|
|
call, if possible. This should not be too difficult.
|
|
|
|
The final step when you have a simple test case is to report the bug.
|
|
Do this at <http://www.gnu.org/software/libc/bugs.html>.
|
|
|
|
If you are not sure how a function should behave, and this manual
|
|
doesn't tell you, that's a bug in the manual. Report that too! If the
|
|
function's behavior disagrees with the manual, then either the library
|
|
or the manual has a bug, so report the disagreement. If you find any
|
|
errors or omissions in this manual, please report them to the bug
|
|
database. If you refer to specific sections of the manual, please
|
|
include the section names for easier identification.
|