forked from mirrors/nixpkgs
1736 lines
64 KiB
XML
1736 lines
64 KiB
XML
<chapter xmlns="http://docbook.org/ns/docbook"
|
||
xmlns:xlink="http://www.w3.org/1999/xlink"
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||
xml:id="chap-stdenv">
|
||
|
||
<title>The Standard Environment</title>
|
||
|
||
|
||
<para>The standard build environment in the Nix Packages collection
|
||
provides an environment for building Unix packages that does a lot of
|
||
common build tasks automatically. In fact, for Unix packages that use
|
||
the standard <literal>./configure; make; make install</literal> build
|
||
interface, you don’t need to write a build script at all; the standard
|
||
environment does everything automatically. If
|
||
<literal>stdenv</literal> doesn’t do what you need automatically, you
|
||
can easily customise or override the various build phases.</para>
|
||
|
||
|
||
<section xml:id="sec-using-stdenv"><title>Using
|
||
<literal>stdenv</literal></title>
|
||
|
||
<para>To build a package with the standard environment, you use the
|
||
function <varname>stdenv.mkDerivation</varname>, instead of the
|
||
primitive built-in function <varname>derivation</varname>, e.g.
|
||
|
||
<programlisting>
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||
stdenv.mkDerivation {
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||
name = "libfoo-1.2.3";
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||
src = fetchurl {
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||
url = http://example.org/libfoo-1.2.3.tar.bz2;
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||
sha256 = "0x2g1jqygyr5wiwg4ma1nd7w4ydpy82z9gkcv8vh2v8dn3y58v5m";
|
||
};
|
||
}</programlisting>
|
||
|
||
(<varname>stdenv</varname> needs to be in scope, so if you write this
|
||
in a separate Nix expression from
|
||
<filename>pkgs/all-packages.nix</filename>, you need to pass it as a
|
||
function argument.) Specifying a <varname>name</varname> and a
|
||
<varname>src</varname> is the absolute minimum you need to do. Many
|
||
packages have dependencies that are not provided in the standard
|
||
environment. It’s usually sufficient to specify those dependencies in
|
||
the <varname>buildInputs</varname> attribute:
|
||
|
||
<programlisting>
|
||
stdenv.mkDerivation {
|
||
name = "libfoo-1.2.3";
|
||
...
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||
buildInputs = [libbar perl ncurses];
|
||
}</programlisting>
|
||
|
||
This attribute ensures that the <filename>bin</filename>
|
||
subdirectories of these packages appear in the <envar>PATH</envar>
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||
environment variable during the build, that their
|
||
<filename>include</filename> subdirectories are searched by the C
|
||
compiler, and so on. (See <xref linkend="ssec-setup-hooks"/> for
|
||
details.)</para>
|
||
|
||
<para>Often it is necessary to override or modify some aspect of the
|
||
build. To make this easier, the standard environment breaks the
|
||
package build into a number of <emphasis>phases</emphasis>, all of
|
||
which can be overridden or modified individually: unpacking the
|
||
sources, applying patches, configuring, building, and installing.
|
||
(There are some others; see <xref linkend="sec-stdenv-phases"/>.)
|
||
For instance, a package that doesn’t supply a makefile but instead has
|
||
to be compiled “manually” could be handled like this:
|
||
|
||
<programlisting>
|
||
stdenv.mkDerivation {
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||
name = "fnord-4.5";
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||
...
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||
buildPhase = ''
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||
gcc foo.c -o foo
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||
'';
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||
installPhase = ''
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||
mkdir -p $out/bin
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||
cp foo $out/bin
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||
'';
|
||
}</programlisting>
|
||
|
||
(Note the use of <literal>''</literal>-style string literals, which
|
||
are very convenient for large multi-line script fragments because they
|
||
don’t need escaping of <literal>"</literal> and <literal>\</literal>,
|
||
and because indentation is intelligently removed.)</para>
|
||
|
||
<para>There are many other attributes to customise the build. These
|
||
are listed in <xref linkend="ssec-stdenv-attributes"/>.</para>
|
||
|
||
<para>While the standard environment provides a generic builder, you
|
||
can still supply your own build script:
|
||
|
||
<programlisting>
|
||
stdenv.mkDerivation {
|
||
name = "libfoo-1.2.3";
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||
...
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||
builder = ./builder.sh;
|
||
}</programlisting>
|
||
|
||
where the builder can do anything it wants, but typically starts with
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||
|
||
<programlisting>
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||
source $stdenv/setup
|
||
</programlisting>
|
||
|
||
to let <literal>stdenv</literal> set up the environment (e.g., process
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||
the <varname>buildInputs</varname>). If you want, you can still use
|
||
<literal>stdenv</literal>’s generic builder:
|
||
|
||
<programlisting>
|
||
source $stdenv/setup
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||
|
||
buildPhase() {
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||
echo "... this is my custom build phase ..."
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||
gcc foo.c -o foo
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||
}
|
||
|
||
installPhase() {
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||
mkdir -p $out/bin
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||
cp foo $out/bin
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||
}
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||
|
||
genericBuild
|
||
</programlisting>
|
||
|
||
</para>
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="sec-tools-of-stdenv"><title>Tools provided by
|
||
<literal>stdenv</literal></title>
|
||
|
||
<para>The standard environment provides the following packages:
|
||
|
||
<itemizedlist>
|
||
|
||
<listitem><para>The GNU C Compiler, configured with C and C++
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||
support.</para></listitem>
|
||
|
||
<listitem><para>GNU coreutils (contains a few dozen standard Unix
|
||
commands).</para></listitem>
|
||
|
||
<listitem><para>GNU findutils (contains
|
||
<command>find</command>).</para></listitem>
|
||
|
||
<listitem><para>GNU diffutils (contains <command>diff</command>,
|
||
<command>cmp</command>).</para></listitem>
|
||
|
||
<listitem><para>GNU <command>sed</command>.</para></listitem>
|
||
|
||
<listitem><para>GNU <command>grep</command>.</para></listitem>
|
||
|
||
<listitem><para>GNU <command>awk</command>.</para></listitem>
|
||
|
||
<listitem><para>GNU <command>tar</command>.</para></listitem>
|
||
|
||
<listitem><para><command>gzip</command>, <command>bzip2</command>
|
||
and <command>xz</command>.</para></listitem>
|
||
|
||
<listitem><para>GNU Make. It has been patched to provide
|
||
<quote>nested</quote> output that can be fed into the
|
||
<command>nix-log2xml</command> command and
|
||
<command>log2html</command> stylesheet to create a structured,
|
||
readable output of the build steps performed by
|
||
Make.</para></listitem>
|
||
|
||
<listitem><para>Bash. This is the shell used for all builders in
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||
the Nix Packages collection. Not using <command>/bin/sh</command>
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||
removes a large source of portability problems.</para></listitem>
|
||
|
||
<listitem><para>The <command>patch</command>
|
||
command.</para></listitem>
|
||
|
||
</itemizedlist>
|
||
|
||
</para>
|
||
|
||
<para>On Linux, <literal>stdenv</literal> also includes the
|
||
<command>patchelf</command> utility.</para>
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="ssec-stdenv-attributes"><title>Attributes</title>
|
||
|
||
<variablelist>
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||
<title>Variables affecting <literal>stdenv</literal>
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||
initialisation</title>
|
||
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||
<varlistentry>
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||
<term><varname>NIX_DEBUG</varname></term>
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||
<listitem><para>If set, <literal>stdenv</literal> will print some
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||
debug information during the build. In particular, the
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||
<command>gcc</command> and <command>ld</command> wrapper scripts
|
||
will print out the complete command line passed to the wrapped
|
||
tools.</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
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||
|
||
<variablelist>
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||
<title>Variables specifying dependencies</title>
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||
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||
<varlistentry>
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||
<term><varname>nativeBuildInputs</varname></term>
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||
<listitem><para>
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||
A list of dependencies used by the new derivation at <emphasis>build</emphasis>-time.
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||
I.e. these dependencies should not make it into the package's runtime-closure, though this is currently not checked.
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||
For each dependency <replaceable>dir</replaceable>, the directory <filename><replaceable>dir</replaceable>/bin</filename>, if it exists, is added to the <envar>PATH</envar> environment variable.
|
||
Other environment variables are also set up via a pluggable mechanism.
|
||
For instance, if <varname>buildInputs</varname> contains Perl, then the <filename>lib/site_perl</filename> subdirectory of each input is added to the <envar>PERL5LIB</envar> environment variable.
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||
See <xref linkend="ssec-setup-hooks"/> for details.
|
||
</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>buildInputs</varname></term>
|
||
<listitem><para>
|
||
A list of dependencies used by the new derivation at <emphasis>run</emphasis>-time.
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||
Currently, the build-time environment is modified in the exact same way as with <varname>nativeBuildInputs</varname>.
|
||
This is problematic in that when cross-compiling, foreign executables can clobber native ones on the <envar>PATH</envar>.
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||
Even more confusing is static-linking.
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||
A statically-linked library should be listed here because ultimately that generated machine code will be used at run-time, even though a derivation containing the object files or static archives will only be used at build-time.
|
||
A less confusing solution to this would be nice.
|
||
</para></listitem>
|
||
</varlistentry>
|
||
|
||
|
||
<varlistentry>
|
||
<term><varname>propagatedNativeBuildInputs</varname></term>
|
||
<listitem><para>
|
||
Like <varname>nativeBuildInputs</varname>, but these dependencies are <emphasis>propagated</emphasis>:
|
||
that is, the dependencies listed here are added to the <varname>nativeBuildInputs</varname> of any package that uses <emphasis>this</emphasis> package as a dependency.
|
||
So if package Y has <literal>propagatedBuildInputs = [X]</literal>, and package Z has <literal>buildInputs = [Y]</literal>, then package X will appear in Z’s build environment automatically.
|
||
</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>propagatedBuildInputs</varname></term>
|
||
<listitem><para>
|
||
Like <varname>buildInputs</varname>, but propagated just like <varname>propagatedNativeBuildInputs</varname>.
|
||
This inherits <varname>buildInputs</varname>'s flaws of clobbering native executables when cross-compiling and being confusing for static linking.
|
||
</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
<variablelist>
|
||
<title>Variables affecting build properties</title>
|
||
|
||
<varlistentry>
|
||
<term><varname>enableParallelBuilding</varname></term>
|
||
<listitem><para>If set, <literal>stdenv</literal> will pass specific
|
||
flags to <literal>make</literal> and other build tools to enable
|
||
parallel building with up to <literal>build-cores</literal>
|
||
workers.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>preferLocalBuild</varname></term>
|
||
<listitem><para>If set, specifies that the package is so lightweight
|
||
in terms of build operations (e.g. write a text file from a Nix string
|
||
to the store) that there's no need to look for it in binary caches --
|
||
it's faster to just build it locally. It also tells Hydra and other
|
||
facilities that this package doesn't need to be exported in binary
|
||
caches (noone would use it, after all).</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
<variablelist>
|
||
<title>Special variables</title>
|
||
|
||
<varlistentry>
|
||
<term><varname>passthru</varname></term>
|
||
<listitem><para>This is an attribute set which can be filled with arbitrary
|
||
values. For example:
|
||
|
||
<programlisting>
|
||
passthru = {
|
||
foo = "bar";
|
||
baz = {
|
||
value1 = 4;
|
||
value2 = 5;
|
||
};
|
||
}
|
||
</programlisting>
|
||
|
||
</para>
|
||
|
||
<para>Values inside it are not passed to the builder, so you can change
|
||
them without triggering a rebuild. However, they can be accessed outside of a
|
||
derivation directly, as if they were set inside a derivation itself, e.g.
|
||
<literal>hello.baz.value1</literal>. We don't specify any usage or
|
||
schema of <literal>passthru</literal> - it is meant for values that would be
|
||
useful outside the derivation in other parts of a Nix expression (e.g. in other
|
||
derivations). An example would be to convey some specific dependency of your
|
||
derivation which contains a program with plugins support. Later, others who
|
||
make derivations with plugins can use passed-through dependency to ensure that
|
||
their plugin would be binary-compatible with built program.</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="sec-stdenv-phases"><title>Phases</title>
|
||
|
||
<para>The generic builder has a number of <emphasis>phases</emphasis>.
|
||
Package builds are split into phases to make it easier to override
|
||
specific parts of the build (e.g., unpacking the sources or installing
|
||
the binaries). Furthermore, it allows a nicer presentation of build
|
||
logs in the Nix build farm.</para>
|
||
|
||
<para>Each phase can be overridden in its entirety either by setting
|
||
the environment variable
|
||
<varname><replaceable>name</replaceable>Phase</varname> to a string
|
||
containing some shell commands to be executed, or by redefining the
|
||
shell function
|
||
<varname><replaceable>name</replaceable>Phase</varname>. The former
|
||
is convenient to override a phase from the derivation, while the
|
||
latter is convenient from a build script.
|
||
|
||
However, typically one only wants to <emphasis>add</emphasis> some
|
||
commands to a phase, e.g. by defining <literal>postInstall</literal>
|
||
or <literal>preFixup</literal>, as skipping some of the default actions
|
||
may have unexpected consequences.
|
||
</para>
|
||
|
||
|
||
<section xml:id="ssec-controlling-phases"><title>Controlling
|
||
phases</title>
|
||
|
||
<para>There are a number of variables that control what phases are
|
||
executed and in what order:
|
||
|
||
<variablelist>
|
||
<title>Variables affecting phase control</title>
|
||
|
||
<varlistentry>
|
||
<term><varname>phases</varname></term>
|
||
<listitem>
|
||
<para>Specifies the phases. You can change the order in which
|
||
phases are executed, or add new phases, by setting this
|
||
variable. If it’s not set, the default value is used, which is
|
||
<literal>$prePhases unpackPhase patchPhase $preConfigurePhases
|
||
configurePhase $preBuildPhases buildPhase checkPhase
|
||
$preInstallPhases installPhase fixupPhase $preDistPhases
|
||
distPhase $postPhases</literal>.
|
||
</para>
|
||
|
||
<para>Usually, if you just want to add a few phases, it’s more
|
||
convenient to set one of the variables below (such as
|
||
<varname>preInstallPhases</varname>), as you then don’t specify
|
||
all the normal phases.</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>prePhases</varname></term>
|
||
<listitem>
|
||
<para>Additional phases executed before any of the default phases.</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>preConfigurePhases</varname></term>
|
||
<listitem>
|
||
<para>Additional phases executed just before the configure phase.</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>preBuildPhases</varname></term>
|
||
<listitem>
|
||
<para>Additional phases executed just before the build phase.</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>preInstallPhases</varname></term>
|
||
<listitem>
|
||
<para>Additional phases executed just before the install phase.</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>preFixupPhases</varname></term>
|
||
<listitem>
|
||
<para>Additional phases executed just before the fixup phase.</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>preDistPhases</varname></term>
|
||
<listitem>
|
||
<para>Additional phases executed just before the distribution phase.</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>postPhases</varname></term>
|
||
<listitem>
|
||
<para>Additional phases executed after any of the default
|
||
phases.</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
</para>
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="ssec-unpack-phase"><title>The unpack phase</title>
|
||
|
||
<para>The unpack phase is responsible for unpacking the source code of
|
||
the package. The default implementation of
|
||
<function>unpackPhase</function> unpacks the source files listed in
|
||
the <envar>src</envar> environment variable to the current directory.
|
||
It supports the following files by default:
|
||
|
||
<variablelist>
|
||
|
||
<varlistentry>
|
||
<term>Tar files</term>
|
||
<listitem><para>These can optionally be compressed using
|
||
<command>gzip</command> (<filename>.tar.gz</filename>,
|
||
<filename>.tgz</filename> or <filename>.tar.Z</filename>),
|
||
<command>bzip2</command> (<filename>.tar.bz2</filename> or
|
||
<filename>.tbz2</filename>) or <command>xz</command>
|
||
(<filename>.tar.xz</filename> or
|
||
<filename>.tar.lzma</filename>).</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>Zip files</term>
|
||
<listitem><para>Zip files are unpacked using
|
||
<command>unzip</command>. However, <command>unzip</command> is
|
||
not in the standard environment, so you should add it to
|
||
<varname>buildInputs</varname> yourself.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>Directories in the Nix store</term>
|
||
<listitem><para>These are simply copied to the current directory.
|
||
The hash part of the file name is stripped,
|
||
e.g. <filename>/nix/store/1wydxgby13cz...-my-sources</filename>
|
||
would be copied to
|
||
<filename>my-sources</filename>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
Additional file types can be supported by setting the
|
||
<varname>unpackCmd</varname> variable (see below).</para>
|
||
|
||
<para></para>
|
||
|
||
<variablelist>
|
||
<title>Variables controlling the unpack phase</title>
|
||
|
||
<varlistentry>
|
||
<term><varname>srcs</varname> / <varname>src</varname></term>
|
||
<listitem><para>The list of source files or directories to be
|
||
unpacked or copied. One of these must be set.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>sourceRoot</varname></term>
|
||
<listitem><para>After running <function>unpackPhase</function>,
|
||
the generic builder changes the current directory to the directory
|
||
created by unpacking the sources. If there are multiple source
|
||
directories, you should set <varname>sourceRoot</varname> to the
|
||
name of the intended directory.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>setSourceRoot</varname></term>
|
||
<listitem><para>Alternatively to setting
|
||
<varname>sourceRoot</varname>, you can set
|
||
<varname>setSourceRoot</varname> to a shell command to be
|
||
evaluated by the unpack phase after the sources have been
|
||
unpacked. This command must set
|
||
<varname>sourceRoot</varname>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>preUnpack</varname></term>
|
||
<listitem><para>Hook executed at the start of the unpack
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>postUnpack</varname></term>
|
||
<listitem><para>Hook executed at the end of the unpack
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>dontMakeSourcesWritable</varname></term>
|
||
<listitem><para>If set to <literal>1</literal>, the unpacked
|
||
sources are <emphasis>not</emphasis> made
|
||
writable. By default, they are made writable to prevent problems
|
||
with read-only sources. For example, copied store directories
|
||
would be read-only without this.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>unpackCmd</varname></term>
|
||
<listitem><para>The unpack phase evaluates the string
|
||
<literal>$unpackCmd</literal> for any unrecognised file. The path
|
||
to the current source file is contained in the
|
||
<varname>curSrc</varname> variable.</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="ssec-patch-phase"><title>The patch phase</title>
|
||
|
||
<para>The patch phase applies the list of patches defined in the
|
||
<varname>patches</varname> variable.</para>
|
||
|
||
<variablelist>
|
||
<title>Variables controlling the patch phase</title>
|
||
|
||
<varlistentry>
|
||
<term><varname>patches</varname></term>
|
||
<listitem><para>The list of patches. They must be in the format
|
||
accepted by the <command>patch</command> command, and may
|
||
optionally be compressed using <command>gzip</command>
|
||
(<filename>.gz</filename>), <command>bzip2</command>
|
||
(<filename>.bz2</filename>) or <command>xz</command>
|
||
(<filename>.xz</filename>).</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>patchFlags</varname></term>
|
||
<listitem><para>Flags to be passed to <command>patch</command>.
|
||
If not set, the argument <option>-p1</option> is used, which
|
||
causes the leading directory component to be stripped from the
|
||
file names in each patch.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>prePatch</varname></term>
|
||
<listitem><para>Hook executed at the start of the patch
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>postPatch</varname></term>
|
||
<listitem><para>Hook executed at the end of the patch
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="ssec-configure-phase"><title>The configure phase</title>
|
||
|
||
<para>The configure phase prepares the source tree for building. The
|
||
default <function>configurePhase</function> runs
|
||
<filename>./configure</filename> (typically an Autoconf-generated
|
||
script) if it exists.</para>
|
||
|
||
<variablelist>
|
||
<title>Variables controlling the configure phase</title>
|
||
|
||
<varlistentry>
|
||
<term><varname>configureScript</varname></term>
|
||
<listitem><para>The name of the configure script. It defaults to
|
||
<filename>./configure</filename> if it exists; otherwise, the
|
||
configure phase is skipped. This can actually be a command (like
|
||
<literal>perl ./Configure.pl</literal>).</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>configureFlags</varname></term>
|
||
<listitem><para>A list of strings passed as additional arguments to the
|
||
configure script.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>configureFlagsArray</varname></term>
|
||
<listitem><para>A shell array containing additional arguments
|
||
passed to the configure script. You must use this instead of
|
||
<varname>configureFlags</varname> if the arguments contain
|
||
spaces.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>dontAddPrefix</varname></term>
|
||
<listitem><para>By default, the flag
|
||
<literal>--prefix=$prefix</literal> is added to the configure
|
||
flags. If this is undesirable, set this variable to
|
||
true.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>prefix</varname></term>
|
||
<listitem><para>The prefix under which the package must be
|
||
installed, passed via the <option>--prefix</option> option to the
|
||
configure script. It defaults to
|
||
<option>$out</option>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>dontAddDisableDepTrack</varname></term>
|
||
<listitem><para>By default, the flag
|
||
<literal>--disable-dependency-tracking</literal> is added to the
|
||
configure flags to speed up Automake-based builds. If this is
|
||
undesirable, set this variable to true.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>dontFixLibtool</varname></term>
|
||
<listitem><para>By default, the configure phase applies some
|
||
special hackery to all files called <filename>ltmain.sh</filename>
|
||
before running the configure script in order to improve the purity
|
||
of Libtool-based packages<footnote><para>It clears the
|
||
<varname>sys_lib_<replaceable>*</replaceable>search_path</varname>
|
||
variables in the Libtool script to prevent Libtool from using
|
||
libraries in <filename>/usr/lib</filename> and
|
||
such.</para></footnote>. If this is undesirable, set this
|
||
variable to true.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>dontDisableStatic</varname></term>
|
||
<listitem><para>By default, when the configure script has
|
||
<option>--enable-static</option>, the option
|
||
<option>--disable-static</option> is added to the configure flags.</para>
|
||
<para>If this is undesirable, set this variable to
|
||
true.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>configurePlatforms</varname></term>
|
||
<listitem><para>
|
||
By default, when cross compiling, the configure script has <option>--build=...</option> and <option>--host=...</option> passed.
|
||
Packages can instead pass <literal>[ "build" "host" "target" ]</literal> or a subset to control exactly which platform flags are passed.
|
||
Compilers and other tools should use this to also pass the target platform, for example.
|
||
Note eventually these will be passed when in native builds too, to improve determinism: build-time guessing, as is done today, is a risk of impurity.
|
||
</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>preConfigure</varname></term>
|
||
<listitem><para>Hook executed at the start of the configure
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>postConfigure</varname></term>
|
||
<listitem><para>Hook executed at the end of the configure
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="build-phase"><title>The build phase</title>
|
||
|
||
<para>The build phase is responsible for actually building the package
|
||
(e.g. compiling it). The default <function>buildPhase</function>
|
||
simply calls <command>make</command> if a file named
|
||
<filename>Makefile</filename>, <filename>makefile</filename> or
|
||
<filename>GNUmakefile</filename> exists in the current directory (or
|
||
the <varname>makefile</varname> is explicitly set); otherwise it does
|
||
nothing.</para>
|
||
|
||
<variablelist>
|
||
<title>Variables controlling the build phase</title>
|
||
|
||
<varlistentry>
|
||
<term><varname>dontBuild</varname></term>
|
||
<listitem><para>Set to true to skip the build phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>makefile</varname></term>
|
||
<listitem><para>The file name of the Makefile.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>makeFlags</varname></term>
|
||
<listitem><para>A list of strings passed as additional flags to
|
||
<command>make</command>. These flags are also used by the default
|
||
install and check phase. For setting make flags specific to the
|
||
build phase, use <varname>buildFlags</varname> (see
|
||
below).</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>makeFlagsArray</varname></term>
|
||
<listitem><para>A shell array containing additional arguments
|
||
passed to <command>make</command>. You must use this instead of
|
||
<varname>makeFlags</varname> if the arguments contain
|
||
spaces, e.g.
|
||
|
||
<programlisting>
|
||
makeFlagsArray=(CFLAGS="-O0 -g" LDFLAGS="-lfoo -lbar")
|
||
</programlisting>
|
||
|
||
Note that shell arrays cannot be passed through environment
|
||
variables, so you cannot set <varname>makeFlagsArray</varname> in
|
||
a derivation attribute (because those are passed through
|
||
environment variables): you have to define them in shell
|
||
code.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>buildFlags</varname> / <varname>buildFlagsArray</varname></term>
|
||
<listitem><para>A list of strings passed as additional flags to
|
||
<command>make</command>. Like <varname>makeFlags</varname> and
|
||
<varname>makeFlagsArray</varname>, but only used by the build
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>preBuild</varname></term>
|
||
<listitem><para>Hook executed at the start of the build
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>postBuild</varname></term>
|
||
<listitem><para>Hook executed at the end of the build
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
|
||
<para>
|
||
You can set flags for <command>make</command> through the
|
||
<varname>makeFlags</varname> variable.</para>
|
||
|
||
<para>Before and after running <command>make</command>, the hooks
|
||
<varname>preBuild</varname> and <varname>postBuild</varname> are
|
||
called, respectively.</para>
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="ssec-check-phase"><title>The check phase</title>
|
||
|
||
<para>The check phase checks whether the package was built correctly
|
||
by running its test suite. The default
|
||
<function>checkPhase</function> calls <command>make check</command>,
|
||
but only if the <varname>doCheck</varname> variable is enabled.</para>
|
||
|
||
<variablelist>
|
||
<title>Variables controlling the check phase</title>
|
||
|
||
<varlistentry>
|
||
<term><varname>doCheck</varname></term>
|
||
<listitem><para>If set to a non-empty string, the check phase is
|
||
executed, otherwise it is skipped (default). Thus you should set
|
||
|
||
<programlisting>
|
||
doCheck = true;</programlisting>
|
||
|
||
in the derivation to enable checks.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>makeFlags</varname> /
|
||
<varname>makeFlagsArray</varname> /
|
||
<varname>makefile</varname></term>
|
||
<listitem><para>See the build phase for details.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>checkTarget</varname></term>
|
||
<listitem><para>The make target that runs the tests. Defaults to
|
||
<literal>check</literal>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>checkFlags</varname> / <varname>checkFlagsArray</varname></term>
|
||
<listitem><para>A list of strings passed as additional flags to
|
||
<command>make</command>. Like <varname>makeFlags</varname> and
|
||
<varname>makeFlagsArray</varname>, but only used by the check
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>preCheck</varname></term>
|
||
<listitem><para>Hook executed at the start of the check
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>postCheck</varname></term>
|
||
<listitem><para>Hook executed at the end of the check
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="ssec-install-phase"><title>The install phase</title>
|
||
|
||
<para>The install phase is responsible for installing the package in
|
||
the Nix store under <envar>out</envar>. The default
|
||
<function>installPhase</function> creates the directory
|
||
<literal>$out</literal> and calls <command>make
|
||
install</command>.</para>
|
||
|
||
<variablelist>
|
||
<title>Variables controlling the install phase</title>
|
||
|
||
<varlistentry>
|
||
<term><varname>makeFlags</varname> /
|
||
<varname>makeFlagsArray</varname> /
|
||
<varname>makefile</varname></term>
|
||
<listitem><para>See the build phase for details.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>installTargets</varname></term>
|
||
<listitem><para>The make targets that perform the installation.
|
||
Defaults to <literal>install</literal>. Example:
|
||
|
||
<programlisting>
|
||
installTargets = "install-bin install-doc";</programlisting>
|
||
|
||
</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>installFlags</varname> / <varname>installFlagsArray</varname></term>
|
||
<listitem><para>A list of strings passed as additional flags to
|
||
<command>make</command>. Like <varname>makeFlags</varname> and
|
||
<varname>makeFlagsArray</varname>, but only used by the install
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>preInstall</varname></term>
|
||
<listitem><para>Hook executed at the start of the install
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>postInstall</varname></term>
|
||
<listitem><para>Hook executed at the end of the install
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="ssec-fixup-phase"><title>The fixup phase</title>
|
||
|
||
<para>The fixup phase performs some (Nix-specific) post-processing
|
||
actions on the files installed under <filename>$out</filename> by the
|
||
install phase. The default <function>fixupPhase</function> does the
|
||
following:
|
||
|
||
<itemizedlist>
|
||
|
||
<listitem><para>It moves the <filename>man/</filename>,
|
||
<filename>doc/</filename> and <filename>info/</filename>
|
||
subdirectories of <envar>$out</envar> to
|
||
<filename>share/</filename>.</para></listitem>
|
||
|
||
<listitem><para>It strips libraries and executables of debug
|
||
information.</para></listitem>
|
||
|
||
<listitem><para>On Linux, it applies the <command>patchelf</command>
|
||
command to ELF executables and libraries to remove unused
|
||
directories from the <literal>RPATH</literal> in order to prevent
|
||
unnecessary runtime dependencies.</para></listitem>
|
||
|
||
<listitem><para>It rewrites the interpreter paths of shell scripts
|
||
to paths found in <envar>PATH</envar>. E.g.,
|
||
<filename>/usr/bin/perl</filename> will be rewritten to
|
||
<filename>/nix/store/<replaceable>some-perl</replaceable>/bin/perl</filename>
|
||
found in <envar>PATH</envar>.</para></listitem>
|
||
|
||
</itemizedlist>
|
||
|
||
</para>
|
||
|
||
<variablelist>
|
||
<title>Variables controlling the fixup phase</title>
|
||
|
||
<varlistentry>
|
||
<term><varname>dontStrip</varname></term>
|
||
<listitem><para>If set, libraries and executables are not
|
||
stripped. By default, they are.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>dontMoveSbin</varname></term>
|
||
<listitem><para>If set, files in <filename>$out/sbin</filename> are not moved
|
||
to <filename>$out/bin</filename>. By default, they are.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>stripAllList</varname></term>
|
||
<listitem><para>List of directories to search for libraries and
|
||
executables from which <emphasis>all</emphasis> symbols should be
|
||
stripped. By default, it’s empty. Stripping all symbols is
|
||
risky, since it may remove not just debug symbols but also ELF
|
||
information necessary for normal execution.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>stripAllFlags</varname></term>
|
||
<listitem><para>Flags passed to the <command>strip</command>
|
||
command applied to the files in the directories listed in
|
||
<varname>stripAllList</varname>. Defaults to <option>-s</option>
|
||
(i.e. <option>--strip-all</option>).</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>stripDebugList</varname></term>
|
||
<listitem><para>List of directories to search for libraries and
|
||
executables from which only debugging-related symbols should be
|
||
stripped. It defaults to <literal>lib bin
|
||
sbin</literal>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>stripDebugFlags</varname></term>
|
||
<listitem><para>Flags passed to the <command>strip</command>
|
||
command applied to the files in the directories listed in
|
||
<varname>stripDebugList</varname>. Defaults to
|
||
<option>-S</option>
|
||
(i.e. <option>--strip-debug</option>).</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>dontPatchELF</varname></term>
|
||
<listitem><para>If set, the <command>patchelf</command> command is
|
||
not used to remove unnecessary <literal>RPATH</literal> entries.
|
||
Only applies to Linux.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>dontPatchShebangs</varname></term>
|
||
<listitem><para>If set, scripts starting with
|
||
<literal>#!</literal> do not have their interpreter paths
|
||
rewritten to paths in the Nix store.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>forceShare</varname></term>
|
||
<listitem><para>The list of directories that must be moved from
|
||
<filename>$out</filename> to <filename>$out/share</filename>.
|
||
Defaults to <literal>man doc info</literal>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>setupHook</varname></term>
|
||
<listitem><para>A package can export a <link
|
||
linkend="ssec-setup-hooks">setup hook</link> by setting this
|
||
variable. The setup hook, if defined, is copied to
|
||
<filename>$out/nix-support/setup-hook</filename>. Environment
|
||
variables are then substituted in it using <function
|
||
linkend="fun-substituteAll">substituteAll</function>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>preFixup</varname></term>
|
||
<listitem><para>Hook executed at the start of the fixup
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>postFixup</varname></term>
|
||
<listitem><para>Hook executed at the end of the fixup
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry xml:id="stdenv-separateDebugInfo">
|
||
<term><varname>separateDebugInfo</varname></term>
|
||
<listitem><para>If set to <literal>true</literal>, the standard
|
||
environment will enable debug information in C/C++ builds. After
|
||
installation, the debug information will be separated from the
|
||
executables and stored in the output named
|
||
<literal>debug</literal>. (This output is enabled automatically;
|
||
you don’t need to set the <varname>outputs</varname> attribute
|
||
explicitly.) To be precise, the debug information is stored in
|
||
<filename><replaceable>debug</replaceable>/lib/debug/.build-id/<replaceable>XX</replaceable>/<replaceable>YYYY…</replaceable></filename>,
|
||
where <replaceable>XXYYYY…</replaceable> is the <replaceable>build
|
||
ID</replaceable> of the binary — a SHA-1 hash of the contents of
|
||
the binary. Debuggers like GDB use the build ID to look up the
|
||
separated debug information.</para>
|
||
|
||
<para>For example, with GDB, you can add
|
||
|
||
<programlisting>
|
||
set debug-file-directory ~/.nix-profile/lib/debug
|
||
</programlisting>
|
||
|
||
to <filename>~/.gdbinit</filename>. GDB will then be able to find
|
||
debug information installed via <literal>nix-env
|
||
-i</literal>.</para>
|
||
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
</section>
|
||
|
||
<section xml:id="ssec-installCheck-phase"><title>The installCheck phase</title>
|
||
|
||
<para>The installCheck phase checks whether the package was installed
|
||
correctly by running its test suite against the installed directories.
|
||
The default <function>installCheck</function> calls <command>make
|
||
installcheck</command>.</para>
|
||
|
||
<variablelist>
|
||
<title>Variables controlling the installCheck phase</title>
|
||
|
||
<varlistentry>
|
||
<term><varname>doInstallCheck</varname></term>
|
||
<listitem><para>If set to a non-empty string, the installCheck phase is
|
||
executed, otherwise it is skipped (default). Thus you should set
|
||
|
||
<programlisting>doInstallCheck = true;</programlisting>
|
||
|
||
in the derivation to enable install checks.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>preInstallCheck</varname></term>
|
||
<listitem><para>Hook executed at the start of the installCheck
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>postInstallCheck</varname></term>
|
||
<listitem><para>Hook executed at the end of the installCheck
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
</section>
|
||
|
||
<section xml:id="ssec-distribution-phase"><title>The distribution
|
||
phase</title>
|
||
|
||
<para>The distribution phase is intended to produce a source
|
||
distribution of the package. The default
|
||
<function>distPhase</function> first calls <command>make
|
||
dist</command>, then it copies the resulting source tarballs to
|
||
<filename>$out/tarballs/</filename>. This phase is only executed if
|
||
the attribute <varname>doDist</varname> is set.</para>
|
||
|
||
<variablelist>
|
||
<title>Variables controlling the distribution phase</title>
|
||
|
||
<varlistentry>
|
||
<term><varname>distTarget</varname></term>
|
||
<listitem><para>The make target that produces the distribution.
|
||
Defaults to <literal>dist</literal>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>distFlags</varname> / <varname>distFlagsArray</varname></term>
|
||
<listitem><para>Additional flags passed to
|
||
<command>make</command>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>tarballs</varname></term>
|
||
<listitem><para>The names of the source distribution files to be
|
||
copied to <filename>$out/tarballs/</filename>. It can contain
|
||
shell wildcards. The default is
|
||
<filename>*.tar.gz</filename>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>dontCopyDist</varname></term>
|
||
<listitem><para>If set, no files are copied to
|
||
<filename>$out/tarballs/</filename>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>preDist</varname></term>
|
||
<listitem><para>Hook executed at the start of the distribution
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>postDist</varname></term>
|
||
<listitem><para>Hook executed at the end of the distribution
|
||
phase.</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
|
||
</section>
|
||
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="ssec-stdenv-functions"><title>Shell functions</title>
|
||
|
||
<para>The standard environment provides a number of useful
|
||
functions.</para>
|
||
|
||
<variablelist>
|
||
|
||
|
||
<varlistentry xml:id='fun-makeWrapper'>
|
||
<term><function>makeWrapper</function>
|
||
<replaceable>executable</replaceable>
|
||
<replaceable>wrapperfile</replaceable>
|
||
<replaceable>args</replaceable></term>
|
||
<listitem><para>Constructs a wrapper for a program with various
|
||
possible arguments. For example:
|
||
|
||
<programlisting>
|
||
# adds `FOOBAR=baz` to `$out/bin/foo`’s environment
|
||
makeWrapper $out/bin/foo $wrapperfile --set FOOBAR baz
|
||
|
||
# prefixes the binary paths of `hello` and `git`
|
||
# Be advised that paths often should be patched in directly
|
||
# (via string replacements or in `configurePhase`).
|
||
makeWrapper $out/bin/foo $wrapperfile --prefix PATH : ${lib.makeBinPath [ hello git ]}
|
||
</programlisting>
|
||
|
||
There’s many more kinds of arguments, they are documented in
|
||
<literal>nixpkgs/pkgs/build-support/setup-hooks/make-wrapper.sh</literal>.</para>
|
||
|
||
<para><literal>wrapProgram</literal> is a convenience function you probably
|
||
want to use most of the time.</para>
|
||
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
|
||
<varlistentry xml:id='fun-substitute'>
|
||
<term><function>substitute</function>
|
||
<replaceable>infile</replaceable>
|
||
<replaceable>outfile</replaceable>
|
||
<replaceable>subs</replaceable></term>
|
||
|
||
<listitem>
|
||
<para>Performs string substitution on the contents of
|
||
<replaceable>infile</replaceable>, writing the result to
|
||
<replaceable>outfile</replaceable>. The substitutions in
|
||
<replaceable>subs</replaceable> are of the following form:
|
||
|
||
<variablelist>
|
||
<varlistentry>
|
||
<term><option>--replace</option>
|
||
<replaceable>s1</replaceable>
|
||
<replaceable>s2</replaceable></term>
|
||
<listitem><para>Replace every occurrence of the string
|
||
<replaceable>s1</replaceable> by
|
||
<replaceable>s2</replaceable>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><option>--subst-var</option>
|
||
<replaceable>varName</replaceable></term>
|
||
<listitem><para>Replace every occurrence of
|
||
<literal>@<replaceable>varName</replaceable>@</literal> by
|
||
the contents of the environment variable
|
||
<replaceable>varName</replaceable>. This is useful for
|
||
generating files from templates, using
|
||
<literal>@<replaceable>...</replaceable>@</literal> in the
|
||
template as placeholders.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><option>--subst-var-by</option>
|
||
<replaceable>varName</replaceable>
|
||
<replaceable>s</replaceable></term>
|
||
<listitem><para>Replace every occurrence of
|
||
<literal>@<replaceable>varName</replaceable>@</literal> by
|
||
the string <replaceable>s</replaceable>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
</para>
|
||
|
||
<para>Example:
|
||
|
||
<programlisting>
|
||
substitute ./foo.in ./foo.out \
|
||
--replace /usr/bin/bar $bar/bin/bar \
|
||
--replace "a string containing spaces" "some other text" \
|
||
--subst-var someVar
|
||
</programlisting>
|
||
|
||
</para>
|
||
|
||
<para><function>substitute</function> is implemented using the
|
||
<command
|
||
xlink:href="http://replace.richardlloyd.org.uk/">replace</command>
|
||
command. Unlike with the <command>sed</command> command, you
|
||
don’t have to worry about escaping special characters. It
|
||
supports performing substitutions on binary files (such as
|
||
executables), though there you’ll probably want to make sure
|
||
that the replacement string is as long as the replaced
|
||
string.</para>
|
||
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
|
||
<varlistentry xml:id='fun-substituteInPlace'>
|
||
<term><function>substituteInPlace</function>
|
||
<replaceable>file</replaceable>
|
||
<replaceable>subs</replaceable></term>
|
||
<listitem><para>Like <function>substitute</function>, but performs
|
||
the substitutions in place on the file
|
||
<replaceable>file</replaceable>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
|
||
<varlistentry xml:id='fun-substituteAll'>
|
||
<term><function>substituteAll</function>
|
||
<replaceable>infile</replaceable>
|
||
<replaceable>outfile</replaceable></term>
|
||
<listitem><para>Replaces every occurrence of
|
||
<literal>@<replaceable>varName</replaceable>@</literal>, where
|
||
<replaceable>varName</replaceable> is any environment variable, in
|
||
<replaceable>infile</replaceable>, writing the result to
|
||
<replaceable>outfile</replaceable>. For instance, if
|
||
<replaceable>infile</replaceable> has the contents
|
||
|
||
<programlisting>
|
||
#! @bash@/bin/sh
|
||
PATH=@coreutils@/bin
|
||
echo @foo@
|
||
</programlisting>
|
||
|
||
and the environment contains
|
||
<literal>bash=/nix/store/bmwp0q28cf21...-bash-3.2-p39</literal>
|
||
and
|
||
<literal>coreutils=/nix/store/68afga4khv0w...-coreutils-6.12</literal>,
|
||
but does not contain the variable <varname>foo</varname>, then the
|
||
output will be
|
||
|
||
<programlisting>
|
||
#! /nix/store/bmwp0q28cf21...-bash-3.2-p39/bin/sh
|
||
PATH=/nix/store/68afga4khv0w...-coreutils-6.12/bin
|
||
echo @foo@
|
||
</programlisting>
|
||
|
||
That is, no substitution is performed for undefined variables.</para>
|
||
|
||
<para>Environment variables that start with an uppercase letter or an
|
||
underscore are filtered out,
|
||
to prevent global variables (like <literal>HOME</literal>) or private
|
||
variables (like <literal>__ETC_PROFILE_DONE</literal>) from accidentally
|
||
getting substituted.
|
||
The variables also have to be valid bash “names”, as
|
||
defined in the bash manpage (alphanumeric or <literal>_</literal>,
|
||
must not start with a number).</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
|
||
<varlistentry xml:id='fun-substituteAllInPlace'>
|
||
<term><function>substituteAllInPlace</function>
|
||
<replaceable>file</replaceable></term>
|
||
<listitem><para>Like <function>substituteAll</function>, but performs
|
||
the substitutions in place on the file
|
||
<replaceable>file</replaceable>.</para></listitem>
|
||
</varlistentry>
|
||
|
||
|
||
<varlistentry xml:id='fun-stripHash'>
|
||
<term><function>stripHash</function>
|
||
<replaceable>path</replaceable></term>
|
||
<listitem><para>Strips the directory and hash part of a store
|
||
path, outputting the name part to <literal>stdout</literal>.
|
||
For example:
|
||
|
||
<programlisting>
|
||
# prints coreutils-8.24
|
||
stripHash "/nix/store/9s9r019176g7cvn2nvcw41gsp862y6b4-coreutils-8.24"
|
||
</programlisting>
|
||
|
||
If you wish to store the result in another variable, then the
|
||
following idiom may be useful:
|
||
|
||
<programlisting>
|
||
name="/nix/store/9s9r019176g7cvn2nvcw41gsp862y6b4-coreutils-8.24"
|
||
someVar=$(stripHash $name)
|
||
</programlisting>
|
||
|
||
</para></listitem>
|
||
</varlistentry>
|
||
|
||
|
||
<varlistentry xml:id='fun-wrapProgram'>
|
||
<term><function>wrapProgram</function>
|
||
<replaceable>executable</replaceable>
|
||
<replaceable>makeWrapperArgs</replaceable></term>
|
||
<listitem><para>Convenience function for <literal>makeWrapper</literal>
|
||
that automatically creates a sane wrapper file
|
||
|
||
It takes all the same arguments as <literal>makeWrapper</literal>,
|
||
except for <literal>--argv0</literal>.</para>
|
||
|
||
<para>It cannot be applied multiple times, since it will overwrite the wrapper
|
||
file.</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
|
||
</variablelist>
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="ssec-setup-hooks"><title>Package setup hooks</title>
|
||
|
||
<para>The following packages provide a setup hook:
|
||
|
||
<variablelist>
|
||
|
||
<varlistentry>
|
||
<term>Binutils Wrapper</term>
|
||
<listitem>
|
||
<para>
|
||
Binutils Wrapper wraps the binary utilities for a bunch of miscellaneous purposes.
|
||
Specifically, GNU Binutils (for Linux, but a mix of cctools and GNU Binutils for Darwin), and a C standard library (glibc or Darwin's libSystem, just for the dynamic loader) are all fed in, and dependency finding, hardening (see below), and purity checks for each are handled by Binutils Wrapper.
|
||
Packages typically depend on CC Wrapper, which in turn (at run time) depends on binutils-wrapper.
|
||
</para>
|
||
<para>
|
||
Binutils Wrapper was only just recently split off from CC Wrapper, so the division of labor is still being worked out.
|
||
For example, it shouldn't care about about the C standard library, but just take a derivation with the dynamic loader (which happens to be the glibc on linux).
|
||
Dependency finding however is a task both wrappers will continue to need to share, and probably the most important to understand.
|
||
It is currently accomplished by collecting directories of host-platform dependencies (i.e. <varname>buildInputs</varname> and <varname>nativeBuildInputs</varname>) in environment variables.
|
||
Binutils Wrapper's setup hook causes any <filename>lib</filename> and <filename>lib64</filename> subdirectories to <envar>NIX_LDFLAGS</envar>.
|
||
Sine CC Wrapper and Binutils Wrapper use the same strategy, most of the Binutils Wrapper code is sparsely commented and refers to CC Wrapper.
|
||
But CC Wrapper's code, by contrast, has quite lengthy comments.
|
||
Binutils Wrapper merely cites those, rather than repeating them, to avoid falling out of sync.
|
||
</para>
|
||
<para>
|
||
A final task of the setup hook is defining a number of standard environment variables to tell build systems which executables full-fill which purpose.
|
||
They are defined to just be the base name of the tools, under the assumption that Binutils Wrapper's binaries will be on the path.
|
||
Firstly, this helps poorly-written packages, e.g. ones that look for just <command>gcc</command> when <envar>CC</envar> isn't defined yet <command>clang</command> is to be used.
|
||
Secondly, this helps packages not get confused when cross-compiling, in which case multiple Binutils Wrappers may be simultaneous in use (targeting different platforms).
|
||
<envar>BUILD_</envar>- and <envar>TARGET_</envar>-prefixed versions of the normal environment variable are defined for the additional Binutils Wrappers, properly disambiguating them.
|
||
</para>
|
||
<para>
|
||
A problem with this final task is that Binutils Wrapper is honest and defines <envar>LD</envar> as <command>ld</command>.
|
||
Most packages, however, firstly use the C compiler for linking, secondly use <envar>LD</envar> anyways, defining it as the C compiler, and thirdly, only so define <envar>LD</envar> when it is undefined as a fallback.
|
||
This triple-threat means Binutils Wrapper will break those packages, as LD is already defined as the actually linker which the package won't override yet doesn't want to use.
|
||
The workaround is to define, just for the problematic package, <envar>LD</envar> as the C compiler.
|
||
A good way to do this would be <command>preConfigure = "LD=$CC"</command>.
|
||
</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>CC Wrapper</term>
|
||
<listitem>
|
||
<para>
|
||
CC Wrapper wraps a C toolchain for a bunch of miscellaneous purposes.
|
||
Specifically, a C compiler (GCC or Clang), Binutils (or the CCTools + binutils mashup when targetting Darwin), and a C standard library (glibc or Darwin's libSystem, just for the dynamic loader) are all fed in, and dependency finding, hardening (see below), and purity checks for each are handled by Binutils Wrapper.
|
||
Packages typically depend on CC Wrapper, which in turn (at run time) depends on Binutils Wrapper.
|
||
</para>
|
||
<para>
|
||
Dependency finding is undoubtedly the main task of CC Wrapper.
|
||
This works just like Binutils Wrapper, except the any <filename>include</filename> subdirectory of any relevant dependency is added to <envar>NIX_CFLAGS_COMPILE</envar>.
|
||
The setup hook itself contains some lengthy comments describing the exact convoluted mechanism by which this is accomplished.
|
||
</para>
|
||
<para>
|
||
CC Wrapper also like Binutils Wrapper defines standard environment variables with the names of the tools it wraps, for the same reasons described above.
|
||
Importantly, while it includes a <command>cc</command> symlink to the c compiler for portability, the <envar>CC</envar> will be defined using the compiler's "real name" (i.e. <command>gcc</command> or <command>clang</command>).
|
||
This helps lousy build systems that inspect on the name of the compiler rather than run it.
|
||
</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>Perl</term>
|
||
<listitem><para>Adds the <filename>lib/site_perl</filename> subdirectory
|
||
of each build input to the <envar>PERL5LIB</envar>
|
||
environment variable.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>Python</term>
|
||
<listitem><para>Adds the
|
||
<filename>lib/${python.libPrefix}/site-packages</filename> subdirectory of
|
||
each build input to the <envar>PYTHONPATH</envar> environment
|
||
variable.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>pkg-config</term>
|
||
<listitem><para>Adds the <filename>lib/pkgconfig</filename> and
|
||
<filename>share/pkgconfig</filename> subdirectories of each
|
||
build input to the <envar>PKG_CONFIG_PATH</envar> environment
|
||
variable.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>Automake</term>
|
||
<listitem><para>Adds the <filename>share/aclocal</filename>
|
||
subdirectory of each build input to the <envar>ACLOCAL_PATH</envar>
|
||
environment variable.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>Autoconf</term>
|
||
<listitem><para>The <varname>autoreconfHook</varname> derivation adds
|
||
<varname>autoreconfPhase</varname>, which runs autoreconf, libtoolize and
|
||
automake, essentially preparing the configure script in autotools-based
|
||
builds.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>libxml2</term>
|
||
<listitem><para>Adds every file named
|
||
<filename>catalog.xml</filename> found under the
|
||
<filename>xml/dtd</filename> and <filename>xml/xsl</filename>
|
||
subdirectories of each build input to the
|
||
<envar>XML_CATALOG_FILES</envar> environment
|
||
variable.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>teTeX / TeX Live</term>
|
||
<listitem><para>Adds the <filename>share/texmf-nix</filename>
|
||
subdirectory of each build input to the <envar>TEXINPUTS</envar>
|
||
environment variable.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>Qt 4</term>
|
||
<listitem><para>Sets the <envar>QTDIR</envar> environment variable
|
||
to Qt’s path.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>gdk-pixbuf</term>
|
||
<listitem><para>Exports <envar>GDK_PIXBUF_MODULE_FILE</envar>
|
||
environment variable the the builder. Add librsvg package
|
||
to <varname>buildInputs</varname> to get svg support.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>GHC</term>
|
||
<listitem><para>Creates a temporary package database and registers
|
||
every Haskell build input in it (TODO: how?).</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>GStreamer</term>
|
||
<listitem><para>Adds the
|
||
GStreamer plugins subdirectory of
|
||
each build input to the <envar>GST_PLUGIN_SYSTEM_PATH_1_0</envar> or
|
||
<envar>GST_PLUGIN_SYSTEM_PATH</envar> environment variable.</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term>paxctl</term>
|
||
<listitem><para>Defines the <varname>paxmark</varname> helper for
|
||
setting per-executable PaX flags on Linux (where it is available by
|
||
default; on all other platforms, <varname>paxmark</varname> is a no-op).
|
||
For example, to disable secure memory protections on the executable
|
||
<replaceable>foo</replaceable>:
|
||
<programlisting>
|
||
postFixup = ''
|
||
paxmark m $out/bin/<replaceable>foo</replaceable>
|
||
'';
|
||
</programlisting>
|
||
The <literal>m</literal> flag is the most common flag and is typically
|
||
required for applications that employ JIT compilation or otherwise need to
|
||
execute code generated at run-time. Disabling PaX protections should be
|
||
considered a last resort: if possible, problematic features should be
|
||
disabled or patched to work with PaX.</para></listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
</para>
|
||
|
||
</section>
|
||
|
||
|
||
<section xml:id="sec-purity-in-nixpkgs"><title>Purity in Nixpkgs</title>
|
||
|
||
<para>[measures taken to prevent dependencies on packages outside the
|
||
store, and what you can do to prevent them]</para>
|
||
|
||
<para>GCC doesn't search in locations such as
|
||
<filename>/usr/include</filename>. In fact, attempts to add such
|
||
directories through the <option>-I</option> flag are filtered out.
|
||
Likewise, the linker (from GNU binutils) doesn't search in standard
|
||
locations such as <filename>/usr/lib</filename>. Programs built on
|
||
Linux are linked against a GNU C Library that likewise doesn't search
|
||
in the default system locations.</para>
|
||
|
||
</section>
|
||
|
||
<section xml:id="sec-hardening-in-nixpkgs"><title>Hardening in Nixpkgs</title>
|
||
|
||
<para>There are flags available to harden packages at compile or link-time.
|
||
These can be toggled using the <varname>stdenv.mkDerivation</varname> parameters
|
||
<varname>hardeningDisable</varname> and <varname>hardeningEnable</varname>.
|
||
</para>
|
||
|
||
<para>
|
||
Both parameters take a list of flags as strings. The special
|
||
<varname>"all"</varname> flag can be passed to <varname>hardeningDisable</varname>
|
||
to turn off all hardening. These flags can also be used as environment variables
|
||
for testing or development purposes.
|
||
</para>
|
||
|
||
<para>The following flags are enabled by default and might require disabling with
|
||
<varname>hardeningDisable</varname> if the program to package is incompatible.
|
||
</para>
|
||
|
||
<variablelist>
|
||
|
||
<varlistentry>
|
||
<term><varname>format</varname></term>
|
||
<listitem><para>Adds the <option>-Wformat -Wformat-security
|
||
-Werror=format-security</option> compiler options. At present,
|
||
this warns about calls to <varname>printf</varname> and
|
||
<varname>scanf</varname> functions where the format string is
|
||
not a string literal and there are no format arguments, as in
|
||
<literal>printf(foo);</literal>. This may be a security hole
|
||
if the format string came from untrusted input and contains
|
||
<literal>%n</literal>.</para>
|
||
|
||
<para>This needs to be turned off or fixed for errors similar to:</para>
|
||
|
||
<programlisting>
|
||
/tmp/nix-build-zynaddsubfx-2.5.2.drv-0/zynaddsubfx-2.5.2/src/UI/guimain.cpp:571:28: error: format not a string literal and no format arguments [-Werror=format-security]
|
||
printf(help_message);
|
||
^
|
||
cc1plus: some warnings being treated as errors
|
||
</programlisting></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>stackprotector</varname></term>
|
||
<listitem>
|
||
<para>Adds the <option>-fstack-protector-strong
|
||
--param ssp-buffer-size=4</option>
|
||
compiler options. This adds safety checks against stack overwrites
|
||
rendering many potential code injection attacks into aborting situations.
|
||
In the best case this turns code injection vulnerabilities into denial
|
||
of service or into non-issues (depending on the application).</para>
|
||
|
||
<para>This needs to be turned off or fixed for errors similar to:</para>
|
||
|
||
<programlisting>
|
||
bin/blib.a(bios_console.o): In function `bios_handle_cup':
|
||
/tmp/nix-build-ipxe-20141124-5cbdc41.drv-0/ipxe-5cbdc41/src/arch/i386/firmware/pcbios/bios_console.c:86: undefined reference to `__stack_chk_fail'
|
||
</programlisting></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>fortify</varname></term>
|
||
<listitem>
|
||
<para>Adds the <option>-O2 -D_FORTIFY_SOURCE=2</option> compiler
|
||
options. During code generation the compiler knows a great deal of
|
||
information about buffer sizes (where possible), and attempts to replace
|
||
insecure unlimited length buffer function calls with length-limited ones.
|
||
This is especially useful for old, crufty code. Additionally, format
|
||
strings in writable memory that contain '%n' are blocked. If an application
|
||
depends on such a format string, it will need to be worked around.
|
||
</para>
|
||
|
||
<para>Additionally, some warnings are enabled which might trigger build
|
||
failures if compiler warnings are treated as errors in the package build.
|
||
In this case, set <option>NIX_CFLAGS_COMPILE</option> to
|
||
<option>-Wno-error=warning-type</option>.</para>
|
||
|
||
<para>This needs to be turned off or fixed for errors similar to:</para>
|
||
|
||
<programlisting>
|
||
malloc.c:404:15: error: return type is an incomplete type
|
||
malloc.c:410:19: error: storage size of 'ms' isn't known
|
||
</programlisting>
|
||
<programlisting>
|
||
strdup.h:22:1: error: expected identifier or '(' before '__extension__'
|
||
</programlisting>
|
||
<programlisting>
|
||
strsep.c:65:23: error: register name not specified for 'delim'
|
||
</programlisting>
|
||
<programlisting>
|
||
installwatch.c:3751:5: error: conflicting types for '__open_2'
|
||
</programlisting>
|
||
<programlisting>
|
||
fcntl2.h:50:4: error: call to '__open_missing_mode' declared with attribute error: open with O_CREAT or O_TMPFILE in second argument needs 3 arguments
|
||
</programlisting>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>pic</varname></term>
|
||
<listitem>
|
||
<para>Adds the <option>-fPIC</option> compiler options. This options adds
|
||
support for position independent code in shared libraries and thus making
|
||
ASLR possible.</para>
|
||
<para>Most notably, the Linux kernel, kernel modules and other code
|
||
not running in an operating system environment like boot loaders won't
|
||
build with PIC enabled. The compiler will is most cases complain that
|
||
PIC is not supported for a specific build.
|
||
</para>
|
||
|
||
<para>This needs to be turned off or fixed for assembler errors similar to:</para>
|
||
|
||
<programlisting>
|
||
ccbLfRgg.s: Assembler messages:
|
||
ccbLfRgg.s:33: Error: missing or invalid displacement expression `private_key_len@GOTOFF'
|
||
</programlisting>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>strictoverflow</varname></term>
|
||
<listitem>
|
||
<para>Signed integer overflow is undefined behaviour according to the C
|
||
standard. If it happens, it is an error in the program as it should check
|
||
for overflow before it can happen, not afterwards. GCC provides built-in
|
||
functions to perform arithmetic with overflow checking, which are correct
|
||
and faster than any custom implementation. As a workaround, the option
|
||
<option>-fno-strict-overflow</option> makes gcc behave as if signed
|
||
integer overflows were defined.
|
||
</para>
|
||
|
||
<para>This flag should not trigger any build or runtime errors.</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>relro</varname></term>
|
||
<listitem>
|
||
<para>Adds the <option>-z relro</option> linker option. During program
|
||
load, several ELF memory sections need to be written to by the linker,
|
||
but can be turned read-only before turning over control to the program.
|
||
This prevents some GOT (and .dtors) overwrite attacks, but at least the
|
||
part of the GOT used by the dynamic linker (.got.plt) is still vulnerable.
|
||
</para>
|
||
|
||
<para>This flag can break dynamic shared object loading. For instance, the
|
||
module systems of Xorg and OpenCV are incompatible with this flag. In almost
|
||
all cases the <varname>bindnow</varname> flag must also be disabled and
|
||
incompatible programs typically fail with similar errors at runtime.</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>bindnow</varname></term>
|
||
<listitem>
|
||
<para>Adds the <option>-z bindnow</option> linker option. During program
|
||
load, all dynamic symbols are resolved, allowing for the complete GOT to
|
||
be marked read-only (due to <varname>relro</varname>). This prevents GOT
|
||
overwrite attacks. For very large applications, this can incur some
|
||
performance loss during initial load while symbols are resolved, but this
|
||
shouldn't be an issue for daemons.
|
||
</para>
|
||
|
||
<para>This flag can break dynamic shared object loading. For instance, the
|
||
module systems of Xorg and PHP are incompatible with this flag. Programs
|
||
incompatible with this flag often fail at runtime due to missing symbols,
|
||
like:</para>
|
||
|
||
<programlisting>
|
||
intel_drv.so: undefined symbol: vgaHWFreeHWRec
|
||
</programlisting>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
<para>The following flags are disabled by default and should be enabled
|
||
with <varname>hardeningEnable</varname> for packages that take untrusted
|
||
input like network services.
|
||
</para>
|
||
|
||
<variablelist>
|
||
|
||
<varlistentry>
|
||
<term><varname>pie</varname></term>
|
||
<listitem>
|
||
<para>Adds the <option>-fPIE</option> compiler and <option>-pie</option>
|
||
linker options. Position Independent Executables are needed to take
|
||
advantage of Address Space Layout Randomization, supported by modern
|
||
kernel versions. While ASLR can already be enforced for data areas in
|
||
the stack and heap (brk and mmap), the code areas must be compiled as
|
||
position-independent. Shared libraries already do this with the
|
||
<varname>pic</varname> flag, so they gain ASLR automatically, but binary
|
||
.text regions need to be build with <varname>pie</varname> to gain ASLR.
|
||
When this happens, ROP attacks are much harder since there are no static
|
||
locations to bounce off of during a memory corruption attack.
|
||
</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
|
||
</variablelist>
|
||
|
||
<para>For more in-depth information on these hardening flags and hardening in
|
||
general, refer to the
|
||
<link xlink:href="https://wiki.debian.org/Hardening">Debian Wiki</link>,
|
||
<link xlink:href="https://wiki.ubuntu.com/Security/Features">Ubuntu Wiki</link>,
|
||
<link xlink:href="https://wiki.gentoo.org/wiki/Project:Hardened">Gentoo Wiki</link>,
|
||
and the <link xlink:href="https://wiki.archlinux.org/index.php/DeveloperWiki:Security">
|
||
Arch Wiki</link>.
|
||
</para>
|
||
|
||
</section>
|
||
|
||
</chapter>
|