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* NEWS: Mention --enable-cet. * manual/install.texi: Document --enable-cet. * INSTALL: Regenerated.
607 lines
29 KiB
Plaintext
607 lines
29 KiB
Plaintext
Installing the GNU C Library
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****************************
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Before you do anything else, you should read the FAQ at
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<https://sourceware.org/glibc/wiki/FAQ>. It answers common questions
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and describes problems you may experience with compilation and
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installation.
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You will need recent versions of several GNU tools: definitely GCC
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and GNU Make, and possibly others. *Note Tools for Compilation::,
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below.
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Configuring and compiling the GNU C Library
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===========================================
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The GNU C Library cannot be compiled in the source directory. You must
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build it in a separate build directory. For example, if you have
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unpacked the GNU C Library sources in '/src/gnu/glibc-VERSION', create a
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directory '/src/gnu/glibc-build' to put the object files in. This
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allows removing the whole build directory in case an error occurs, which
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is the safest way to get a fresh start and should always be done.
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From your object directory, run the shell script 'configure' located
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at the top level of the source tree. In the scenario above, you'd type
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$ ../glibc-VERSION/configure ARGS...
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Please note that even though you're building in a separate build
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directory, the compilation may need to create or modify files and
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directories in the source directory.
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'configure' takes many options, but the only one that is usually
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mandatory is '--prefix'. This option tells 'configure' where you want
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the GNU C Library installed. This defaults to '/usr/local', but the
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normal setting to install as the standard system library is
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'--prefix=/usr' for GNU/Linux systems and '--prefix=' (an empty prefix)
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for GNU/Hurd systems.
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It may also be useful to pass 'CC=COMPILER' and 'CFLAGS=FLAGS'
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arguments to 'configure'. 'CC' selects the C compiler that will be
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used, and 'CFLAGS' sets optimization options for the compiler. Any
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compiler options required for all compilations, such as options
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selecting an ABI or a processor for which to generate code, should be
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included in 'CC'. Options that may be overridden by the GNU C Library
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build system for particular files, such as for optimization and
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debugging, should go in 'CFLAGS'. The default value of 'CFLAGS' is '-g
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-O2', and the GNU C Library cannot be compiled without optimization, so
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if 'CFLAGS' is specified it must enable optimization. For example:
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$ ../glibc-VERSION/configure CC="gcc -m32" CFLAGS="-O3"
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The following list describes all of the available options for
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'configure':
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'--prefix=DIRECTORY'
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Install machine-independent data files in subdirectories of
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'DIRECTORY'. The default is to install in '/usr/local'.
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'--exec-prefix=DIRECTORY'
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Install the library and other machine-dependent files in
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subdirectories of 'DIRECTORY'. The default is to the '--prefix'
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directory if that option is specified, or '/usr/local' otherwise.
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'--with-headers=DIRECTORY'
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Look for kernel header files in DIRECTORY, not '/usr/include'. The
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GNU C Library needs information from the kernel's header files
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describing the interface to the kernel. The GNU C Library will
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normally look in '/usr/include' for them, but if you specify this
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option, it will look in DIRECTORY instead.
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This option is primarily of use on a system where the headers in
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'/usr/include' come from an older version of the GNU C Library.
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Conflicts can occasionally happen in this case. You can also use
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this option if you want to compile the GNU C Library with a newer
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set of kernel headers than the ones found in '/usr/include'.
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'--enable-kernel=VERSION'
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This option is currently only useful on GNU/Linux systems. The
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VERSION parameter should have the form X.Y.Z and describes the
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smallest version of the Linux kernel the generated library is
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expected to support. The higher the VERSION number is, the less
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compatibility code is added, and the faster the code gets.
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'--with-binutils=DIRECTORY'
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Use the binutils (assembler and linker) in 'DIRECTORY', not the
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ones the C compiler would default to. You can use this option if
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the default binutils on your system cannot deal with all the
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constructs in the GNU C Library. In that case, 'configure' will
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detect the problem and suppress these constructs, so that the
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library will still be usable, but functionality may be lost--for
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example, you can't build a shared libc with old binutils.
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'--disable-shared'
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Don't build shared libraries even if it is possible. Not all
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systems support shared libraries; you need ELF support and
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(currently) the GNU linker.
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'--enable-static-pie'
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Enable static position independent executable (static PIE) support.
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Static PIE is similar to static executable, but can be loaded at
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any address without help from a dynamic linker. All static
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programs as well as static tests are built as static PIE, except
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for those marked with no-pie. The resulting glibc can be used with
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the GCC option, -static-pie, which is available with GCC 8 or
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above, to create static PIE. This option also implies that glibc
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programs and tests are created as dynamic position independent
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executables (PIE) by default.
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'--enable-cet'
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Enable Intel Control-flow Enforcement Technology (CET) support.
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When the GNU C Library is built with '--enable-cet', the resulting
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library is protected with indirect branch tracking (IBT) and shadow
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stack (SHSTK). When CET is enabled, the GNU C Library is
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compatible with all existing executables and shared libraries.
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This feature is currently supported on i386, x86_64 and x32 with
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GCC 8 and binutils 2.29 or later. Note that when CET is enabled,
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the GNU C Library requires CPUs capable of multi-byte NOPs, like
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x86-64 processors as well as Intel Pentium Pro or newer.
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'--disable-profile'
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Don't build libraries with profiling information. You may want to
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use this option if you don't plan to do profiling.
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'--enable-static-nss'
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Compile static versions of the NSS (Name Service Switch) libraries.
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This is not recommended because it defeats the purpose of NSS; a
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program linked statically with the NSS libraries cannot be
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dynamically reconfigured to use a different name database.
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'--enable-hardcoded-path-in-tests'
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By default, dynamic tests are linked to run with the installed C
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library. This option hardcodes the newly built C library path in
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dynamic tests so that they can be invoked directly.
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'--disable-timezone-tools'
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By default, timezone related utilities ('zic', 'zdump', and
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'tzselect') are installed with the GNU C Library. If you are
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building these independently (e.g. by using the 'tzcode' package),
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then this option will allow disabling the install of these.
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Note that you need to make sure the external tools are kept in sync
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with the versions that the GNU C Library expects as the data
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formats may change over time. Consult the 'timezone' subdirectory
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for more details.
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'--enable-stack-protector'
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'--enable-stack-protector=strong'
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'--enable-stack-protector=all'
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Compile the C library and all other parts of the glibc package
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(including the threading and math libraries, NSS modules, and
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transliteration modules) using the GCC '-fstack-protector',
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'-fstack-protector-strong' or '-fstack-protector-all' options to
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detect stack overruns. Only the dynamic linker and a small number
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of routines called directly from assembler are excluded from this
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protection.
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'--enable-bind-now'
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Disable lazy binding for installed shared objects. This provides
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additional security hardening because it enables full RELRO and a
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read-only global offset table (GOT), at the cost of slightly
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increased program load times.
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'--enable-pt_chown'
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The file 'pt_chown' is a helper binary for 'grantpt' (*note
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Pseudo-Terminals: Allocation.) that is installed setuid root to fix
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up pseudo-terminal ownership. It is not built by default because
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systems using the Linux kernel are commonly built with the 'devpts'
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filesystem enabled and mounted at '/dev/pts', which manages
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pseudo-terminal ownership automatically. By using
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'--enable-pt_chown', you may build 'pt_chown' and install it setuid
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and owned by 'root'. The use of 'pt_chown' introduces additional
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security risks to the system and you should enable it only if you
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understand and accept those risks.
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'--disable-werror'
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By default, the GNU C Library is built with '-Werror'. If you wish
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to build without this option (for example, if building with a newer
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version of GCC than this version of the GNU C Library was tested
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with, so new warnings cause the build with '-Werror' to fail), you
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can configure with '--disable-werror'.
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'--disable-mathvec'
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By default for x86_64, the GNU C Library is built with the vector
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math library. Use this option to disable the vector math library.
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'--enable-tunables'
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Tunables support allows additional library parameters to be
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customized at runtime. This feature is enabled by default. This
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option can take the following values:
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'yes'
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This is the default if no option is passed to configure. This
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enables tunables and selects the default frontend (currently
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'valstring').
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'no'
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This option disables tunables.
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'valstring'
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This enables tunables and selects the 'valstring' frontend for
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tunables. This frontend allows users to specify tunables as a
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colon-separated list in a single environment variable
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'GLIBC_TUNABLES'.
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'--enable-obsolete-nsl'
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By default, libnsl is only built as shared library for backward
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compatibility and the NSS modules libnss_compat, libnss_nis and
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libnss_nisplus are not built at all. Use this option to enable
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libnsl with all depending NSS modules and header files.
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'--disable-crypt'
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Do not install the passphrase-hashing library 'libcrypt' or the
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header file 'crypt.h'. 'unistd.h' will still declare the function
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'crypt'. Using this option does not change the set of programs
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that may need to be linked with '-lcrypt'; it only means that the
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GNU C Library will not provide that library.
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This option is for hackers and distributions experimenting with
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independently-maintained implementations of libcrypt. It may
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become the default in a future release.
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'--disable-experimental-malloc'
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By default, a per-thread cache is enabled in 'malloc'. While this
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cache can be disabled on a per-application basis using tunables
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(set glibc.malloc.tcache_count to zero), this option can be used to
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remove it from the build completely.
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'--build=BUILD-SYSTEM'
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'--host=HOST-SYSTEM'
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These options are for cross-compiling. If you specify both options
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and BUILD-SYSTEM is different from HOST-SYSTEM, 'configure' will
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prepare to cross-compile the GNU C Library from BUILD-SYSTEM to be
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used on HOST-SYSTEM. You'll probably need the '--with-headers'
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option too, and you may have to override CONFIGURE's selection of
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the compiler and/or binutils.
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If you only specify '--host', 'configure' will prepare for a native
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compile but use what you specify instead of guessing what your
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system is. This is most useful to change the CPU submodel. For
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example, if 'configure' guesses your machine as 'i686-pc-linux-gnu'
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but you want to compile a library for 586es, give
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'--host=i586-pc-linux-gnu' or just '--host=i586-linux' and add the
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appropriate compiler flags ('-mcpu=i586' will do the trick) to
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'CC'.
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If you specify just '--build', 'configure' will get confused.
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'--with-pkgversion=VERSION'
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Specify a description, possibly including a build number or build
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date, of the binaries being built, to be included in '--version'
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output from programs installed with the GNU C Library. For
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example, '--with-pkgversion='FooBar GNU/Linux glibc build 123''.
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The default value is 'GNU libc'.
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'--with-bugurl=URL'
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Specify the URL that users should visit if they wish to report a
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bug, to be included in '--help' output from programs installed with
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the GNU C Library. The default value refers to the main
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bug-reporting information for the GNU C Library.
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To build the library and related programs, type 'make'. This will
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produce a lot of output, some of which may look like errors from 'make'
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but aren't. Look for error messages from 'make' containing '***'.
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Those indicate that something is seriously wrong.
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The compilation process can take a long time, depending on the
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configuration and the speed of your machine. Some complex modules may
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take a very long time to compile, as much as several minutes on slower
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machines. Do not panic if the compiler appears to hang.
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If you want to run a parallel make, simply pass the '-j' option with
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an appropriate numeric parameter to 'make'. You need a recent GNU
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'make' version, though.
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To build and run test programs which exercise some of the library
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facilities, type 'make check'. If it does not complete successfully, do
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not use the built library, and report a bug after verifying that the
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problem is not already known. *Note Reporting Bugs::, for instructions
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on reporting bugs. Note that some of the tests assume they are not
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being run by 'root'. We recommend you compile and test the GNU C
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Library as an unprivileged user.
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Before reporting bugs make sure there is no problem with your system.
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The tests (and later installation) use some pre-existing files of the
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system such as '/etc/passwd', '/etc/nsswitch.conf' and others. These
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files must all contain correct and sensible content.
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Normally, 'make check' will run all the tests before reporting all
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problems found and exiting with error status if any problems occurred.
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You can specify 'stop-on-test-failure=y' when running 'make check' to
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make the test run stop and exit with an error status immediately when a
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failure occurs.
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The GNU C Library pretty printers come with their own set of scripts
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for testing, which run together with the rest of the testsuite through
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'make check'. These scripts require the following tools to run
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successfully:
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* Python 2.7.6/3.4.3 or later
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Python is required for running the printers' test scripts.
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* PExpect 4.0
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The printer tests drive GDB through test programs and compare its
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output to the printers'. PExpect is used to capture the output of
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GDB, and should be compatible with the Python version in your
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system.
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* GDB 7.8 or later with support for Python 2.7.6/3.4.3 or later
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GDB itself needs to be configured with Python support in order to
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use the pretty printers. Notice that your system having Python
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available doesn't imply that GDB supports it, nor that your
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system's Python and GDB's have the same version.
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If these tools are absent, the printer tests will report themselves as
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'UNSUPPORTED'. Notice that some of the printer tests require the GNU C
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Library to be compiled with debugging symbols.
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To format the 'GNU C Library Reference Manual' for printing, type
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'make dvi'. You need a working TeX installation to do this. The
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distribution builds the on-line formatted version of the manual, as Info
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files, as part of the build process. You can build them manually with
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'make info'.
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The library has a number of special-purpose configuration parameters
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which you can find in 'Makeconfig'. These can be overwritten with the
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file 'configparms'. To change them, create a 'configparms' in your
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build directory and add values as appropriate for your system. The file
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is included and parsed by 'make' and has to follow the conventions for
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makefiles.
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It is easy to configure the GNU C Library for cross-compilation by
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setting a few variables in 'configparms'. Set 'CC' to the
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cross-compiler for the target you configured the library for; it is
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important to use this same 'CC' value when running 'configure', like
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this: 'configure TARGET CC=TARGET-gcc'. Set 'BUILD_CC' to the compiler
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to use for programs run on the build system as part of compiling the
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library. You may need to set 'AR' to cross-compiling versions of 'ar'
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if the native tools are not configured to work with object files for the
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target you configured for. When cross-compiling the GNU C Library, it
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may be tested using 'make check
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test-wrapper="SRCDIR/scripts/cross-test-ssh.sh HOSTNAME"', where SRCDIR
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is the absolute directory name for the main source directory and
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HOSTNAME is the host name of a system that can run the newly built
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binaries of the GNU C Library. The source and build directories must be
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visible at the same locations on both the build system and HOSTNAME.
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In general, when testing the GNU C Library, 'test-wrapper' may be set
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to the name and arguments of any program to run newly built binaries.
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This program must preserve the arguments to the binary being run, its
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working directory and the standard input, output and error file
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descriptors. If 'TEST-WRAPPER env' will not work to run a program with
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environment variables set, then 'test-wrapper-env' must be set to a
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program that runs a newly built program with environment variable
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assignments in effect, those assignments being specified as 'VAR=VALUE'
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before the name of the program to be run. If multiple assignments to
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the same variable are specified, the last assignment specified must take
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precedence. Similarly, if 'TEST-WRAPPER env -i' will not work to run a
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program with an environment completely empty of variables except those
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directly assigned, then 'test-wrapper-env-only' must be set; its use has
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the same syntax as 'test-wrapper-env', the only difference in its
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semantics being starting with an empty set of environment variables
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rather than the ambient set.
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Installing the C Library
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========================
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To install the library and its header files, and the Info files of the
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manual, type 'make install'. This will build things, if necessary,
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before installing them; however, you should still compile everything
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first. If you are installing the GNU C Library as your primary C
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library, we recommend that you shut the system down to single-user mode
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first, and reboot afterward. This minimizes the risk of breaking things
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when the library changes out from underneath.
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'make install' will do the entire job of upgrading from a previous
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installation of the GNU C Library version 2.x. There may sometimes be
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headers left behind from the previous installation, but those are
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generally harmless. If you want to avoid leaving headers behind you can
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do things in the following order.
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You must first build the library ('make'), optionally check it ('make
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check'), switch the include directories and then install ('make
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install'). The steps must be done in this order. Not moving the
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directory before install will result in an unusable mixture of header
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files from both libraries, but configuring, building, and checking the
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library requires the ability to compile and run programs against the old
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library. The new '/usr/include', after switching the include
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directories and before installing the library should contain the Linux
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headers, but nothing else. If you do this, you will need to restore any
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headers from libraries other than the GNU C Library yourself after
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installing the library.
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You can install the GNU C Library somewhere other than where you
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configured it to go by setting the 'DESTDIR' GNU standard make variable
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on the command line for 'make install'. The value of this variable is
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prepended to all the paths for installation. This is useful when
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setting up a chroot environment or preparing a binary distribution. The
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directory should be specified with an absolute file name. Installing
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with the 'prefix' and 'exec_prefix' GNU standard make variables set is
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not supported.
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The GNU C Library includes a daemon called 'nscd', which you may or
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may not want to run. 'nscd' caches name service lookups; it can
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dramatically improve performance with NIS+, and may help with DNS as
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well.
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One auxiliary program, '/usr/libexec/pt_chown', is installed setuid
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'root' if the '--enable-pt_chown' configuration option is used. This
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program is invoked by the 'grantpt' function; it sets the permissions on
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a pseudoterminal so it can be used by the calling process. If you are
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using a Linux kernel with the 'devpts' filesystem enabled and mounted at
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'/dev/pts', you don't need this program.
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After installation you might want to configure the timezone and
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locale installation of your system. The GNU C Library comes with a
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locale database which gets configured with 'localedef'. For example, to
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set up a German locale with name 'de_DE', simply issue the command
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'localedef -i de_DE -f ISO-8859-1 de_DE'. To configure all locales that
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are supported by the GNU C Library, you can issue from your build
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directory the command 'make localedata/install-locales'.
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To configure the locally used timezone, set the 'TZ' environment
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variable. The script 'tzselect' helps you to select the right value.
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As an example, for Germany, 'tzselect' would tell you to use
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'TZ='Europe/Berlin''. For a system wide installation (the given paths
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are for an installation with '--prefix=/usr'), link the timezone file
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which is in '/usr/share/zoneinfo' to the file '/etc/localtime'. For
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Germany, you might execute 'ln -s /usr/share/zoneinfo/Europe/Berlin
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/etc/localtime'.
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Recommended Tools for Compilation
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=================================
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We recommend installing the following GNU tools before attempting to
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build the GNU C Library:
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* GNU 'make' 4.0 or newer
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* GCC 4.9 or newer
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GCC 4.9 or higher is required. In general it is recommended to use
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the newest version of the compiler that is known to work for
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building the GNU C Library, as newer compilers usually produce
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better code. As of release time, GCC 7.3 is the newest compiler
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verified to work to build the GNU C Library.
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For PowerPC 64-bits little-endian (powerpc64le), GCC 6.2 or higher
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is required. This compiler version is the first to provide the
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features required for building the GNU C Library with support for
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'_Float128'.
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For multi-arch support it is recommended to use a GCC which has
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been built with support for GNU indirect functions. This ensures
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that correct debugging information is generated for functions
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selected by IFUNC resolvers. This support can either be enabled by
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configuring GCC with '--enable-gnu-indirect-function', or by
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enabling it by default by setting 'default_gnu_indirect_function'
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variable for a particular architecture in the GCC source file
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'gcc/config.gcc'.
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You can use whatever compiler you like to compile programs that use
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the GNU C Library.
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Check the FAQ for any special compiler issues on particular
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platforms.
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* GNU 'binutils' 2.25 or later
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You must use GNU 'binutils' (as and ld) to build the GNU C Library.
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No other assembler or linker has the necessary functionality at the
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moment. As of release time, GNU 'binutils' 2.29.1 is the newest
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verified to work to build the GNU C Library.
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* GNU 'texinfo' 4.7 or later
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To correctly translate and install the Texinfo documentation you
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need this version of the 'texinfo' package. Earlier versions do
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not understand all the tags used in the document, and the
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installation mechanism for the info files is not present or works
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differently. As of release time, 'texinfo' 6.5 is the newest
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verified to work to build the GNU C Library.
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* GNU 'awk' 3.1.2, or higher
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'awk' is used in several places to generate files. Some 'gawk'
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extensions are used, including the 'asorti' function, which was
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introduced in version 3.1.2 of 'gawk'. As of release time, 'gawk'
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version 4.2.0 is the newest verified to work to build the GNU C
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Library.
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* GNU 'bison' 2.7 or later
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'bison' is used to generate the 'yacc' parser code in the 'intl'
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subdirectory. As of release time, 'bison' version 3.0.4 is the
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newest verified to work to build the GNU C Library.
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* Perl 5
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Perl is not required, but it is used if present to test the
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installation. We may decide to use it elsewhere in the future.
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* GNU 'sed' 3.02 or newer
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'Sed' is used in several places to generate files. Most scripts
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work with any version of 'sed'. As of release time, 'sed' version
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4.4 is the newest verified to work to build the GNU C Library.
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If you change any of the 'configure.ac' files you will also need
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* GNU 'autoconf' 2.69 (exactly)
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and if you change any of the message translation files you will need
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* GNU 'gettext' 0.10.36 or later
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You may also need these packages if you upgrade your source tree using
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patches, although we try to avoid this.
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Specific advice for GNU/Linux systems
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=====================================
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If you are installing the GNU C Library on GNU/Linux systems, you need
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to have the header files from a 3.2 or newer kernel around for
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reference. (For the ia64 architecture, you need version 3.2.18 or newer
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because this is the first version with support for the 'accept4' system
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call.) These headers must be installed using 'make headers_install';
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the headers present in the kernel source directory are not suitable for
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direct use by the GNU C Library. You do not need to use that kernel,
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just have its headers installed where the GNU C Library can access them,
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referred to here as INSTALL-DIRECTORY. The easiest way to do this is to
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unpack it in a directory such as '/usr/src/linux-VERSION'. In that
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directory, run 'make headers_install
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INSTALL_HDR_PATH=INSTALL-DIRECTORY'. Finally, configure the GNU C
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Library with the option '--with-headers=INSTALL-DIRECTORY/include'. Use
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the most recent kernel you can get your hands on. (If you are
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cross-compiling the GNU C Library, you need to specify
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'ARCH=ARCHITECTURE' in the 'make headers_install' command, where
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ARCHITECTURE is the architecture name used by the Linux kernel, such as
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'x86' or 'powerpc'.)
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After installing the GNU C Library, you may need to remove or rename
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directories such as '/usr/include/linux' and '/usr/include/asm', and
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replace them with copies of directories such as 'linux' and 'asm' from
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'INSTALL-DIRECTORY/include'. All directories present in
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'INSTALL-DIRECTORY/include' should be copied, except that the GNU C
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Library provides its own version of '/usr/include/scsi'; the files
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provided by the kernel should be copied without replacing those provided
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by the GNU C Library. The 'linux', 'asm' and 'asm-generic' directories
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are required to compile programs using the GNU C Library; the other
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directories describe interfaces to the kernel but are not required if
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not compiling programs using those interfaces. You do not need to copy
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kernel headers if you did not specify an alternate kernel header source
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using '--with-headers'.
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The Filesystem Hierarchy Standard for GNU/Linux systems expects some
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components of the GNU C Library installation to be in '/lib' and some in
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'/usr/lib'. This is handled automatically if you configure the GNU C
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Library with '--prefix=/usr'. If you set some other prefix or allow it
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to default to '/usr/local', then all the components are installed there.
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Reporting Bugs
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==============
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There are probably bugs in the GNU C Library. There are certainly
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errors and omissions in this manual. If you report them, they will get
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fixed. If you don't, no one will ever know about them and they will
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remain unfixed for all eternity, if not longer.
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It is a good idea to verify that the problem has not already been
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reported. Bugs are documented in two places: The file 'BUGS' describes
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a number of well known bugs and the central GNU C Library bug tracking
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system has a WWW interface at <https://sourceware.org/bugzilla/>. The
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WWW interface gives you access to open and closed reports. A closed
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report normally includes a patch or a hint on solving the problem.
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To report a bug, first you must find it. With any luck, this will be
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the hard part. Once you've found a bug, make sure it's really a bug. A
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good way to do this is to see if the GNU C Library behaves the same way
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some other C library does. If so, probably you are wrong and the
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libraries are right (but not necessarily). If not, one of the libraries
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is probably wrong. It might not be the GNU C Library. Many historical
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Unix C libraries permit things that we don't, such as closing a file
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twice.
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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
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|
Portability::), that is definitely a bug. Report it!
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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
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call, if possible. This should not be too difficult.
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The final step when you have a simple test case is to report the bug.
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Do this at <http://www.gnu.org/software/libc/bugs.html>.
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If you are not sure how a function should behave, and this manual
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doesn't tell you, that's a bug in the manual. Report that too! If the
|
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function's behavior disagrees with the manual, then either the library
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|
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
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database. If you refer to specific sections of the manual, please
|
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include the section names for easier identification.
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