libinput/doc/building.dox

/**
@page building_libinput libinput build instructions

@tableofcontents

Instructions on how to build libinput and its tools and how to build against
libinput.

The build instruction on this page detail how to overwrite your
system-provided libinput with one from the git repository, see
see @ref reverting_install to revert to the previous state.

@section building Building libinput

libinput uses [meson](https://www.mesonbuild.com) and
[ninja](https://www.ninja-build.org). A build is usually the three-step
process below.  A successful build requires the @ref
building_dependencies to be installed before running meson.

@code
$> git clone git://anongit.freedesktop.org/git/wayland/libinput
$> cd libinput
$> meson --prefix=/usr builddir/
$> ninja -C builddir/
$> sudo ninja -C builddir/ install
$> sudo udevadm hwdb --update
@endcode

Additional options may also be specified. For example:
@code
$> meson --prefix=/usr -Ddocumentation=false -Dlibwacom=false builddir/
@endcode

The ```prefix``` or other options can be changed later with the
```mesonconf``` command. For example:
@code
$> mesonconf builddir/ -Dprefix=/some/other/prefix -Ddocumentation=true
$> ninja -C builddir
$> sudo ninja -C builddir/ install
@endcode

Running ``mesonconf builddir/`` with no other arguments lists all
configurable options meson provides.

To rebuild from scratch, simply remove the build directory and run meson
again:
@code
$> rm -r builddir/
$> meson --prefix=....
@endcode

@subsection verifying_install Verifying the install

To verify the install worked correctly, check that libinput.so.x.x.x is in
the library path and that all symlinks point to the new library.
<pre>
$> ls -l /usr/lib64/libinput.*
-rwxr-xr-x 1 root root    946 Apr 28  2015 /usr/lib64/libinput.la
lrwxrwxrwx 1 root root     19 Feb  1 15:12 /usr/lib64/libinput.so -> libinput.so.10.11.2
lrwxrwxrwx 1 root root     19 Feb  1 15:12 /usr/lib64/libinput.so.10 -> libinput.so.10.11.2
-rwxr-xr-x 1 root root 204992 Feb  1 15:12 /usr/lib64/libinput.so.10.11.2
</pre>

The .so installed from git master may have a lower number than the
system-provided one. In that case, manually adjust the symlinks to point to
the newly installed .so.x.x.x

@subsection reverting_install Reverting to the system-provided libinput package

The recommended way to revert to the system install is to use the package
manager to reinstall the libinput package. In some cases, this may leave
files in the system (e.g. ```/usr/lib/libinput.la```) but these files are
usually harmless. To definitely remove all files, run the following command
from the libinput source directory:

@code
$> sudo ninja -C builddir/ uninstall
# WARNING: Do not restart the computer/X/the Wayland compositor after
# uninstall, reinstall the system package immediately!
@endcode

The following commands reinstall the current system package for libinput,
overwriting manually installed files.

<ul>
<li><b>Debian/Ubuntu</b> based distributions: ```sudo apt-get install
--reinstall libinput```</li>
<li><b>Fedora 22</b> and later: ```sudo dnf reinstall libinput```</li>
<li><b>RHEL/CentOS/Fedora 21</b> and earlier: ```sudo yum reinstall libinput```</li>
<li><b>openSUSE</b>: ```sudo zypper install --force libinput10```</li>
<li><b>Arch</b>: ```sudo packman -S libinput```</li>
</ul>

@subsection building_selinux SELinux adjustments

On systems with SELinux, overwriting the distribution-provided package with
a manually built libinput may cause SELinux denials. This usually manifests
when gdm does not start because it is denied access to libinput. The journal
shows a log message in the form of:

<pre>
May 25 15:28:42 localhost.localdomain audit[23268]: AVC avc:  denied  { execute } for  pid=23268 comm="gnome-shell" path="/usr/lib64/libinput.so.10.12.2" dev="dm-0" ino=1709093 scontext=system_u:system_r:xdm_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=0
May 25 15:28:42 localhost.localdomain org.gnome.Shell.desktop[23270]: /usr/bin/gnome-shell: error while loading shared libraries: libinput.so.10: failed to map segment from shared object
</pre>

The summary of this error message is that gdm's gnome-shell runs in the
```system_u:system_r:xdm_t``` context but libinput is installed with the
context ```unconfined_u:object_r:user_home_t```.

To avoid this issue, restore the SELinux context for any system files.

<pre>
$> sudo restorecon /usr/lib*/libinput.so.*
</pre>

This issue is tracked in https://github.com/mesonbuild/meson/issues/1967.

@subsection building_dependencies Build dependencies

libinput has a few build-time dependencies that must be installed prior to
running configure. In most cases, it is sufficient to install the
dependencies that your distribution uses to build the libinput package.
These can be installed with one of the following commands:

<ul>
<li><b>Debian/Ubuntu</b> based distributions: ```sudo apt-get build-dep
libinput```</li>
<li><b>Fedora 22</b> and later: ```sudo dnf builddep libinput```</li>
<li><b>RHEL/CentOS/Fedora 21</b> and earlier: ```sudo yum-builddep libinput```</li>
<li><b>openSUSE</b>:
<pre>
$> sudo zypper modifyrepo --enable `zypper repos | grep source | awk '{print $5}'`
$> sudo zypper source-install -d libinput10
$> sudo zypper install autoconf automake libtool
$> sudo zypper modifyrepo --disable `zypper repos | grep source | awk '{print $5}'`
</pre>
</li>
<li><b>Arch</b>:
<pre>
$> sudo pacman -S asp
$> cd $(mktemp -d)
$> asp export libinput
$> cd libinput
$> makepkg --syncdeps --nobuild --noextract
</pre>
</li>
</ul>

If dependencies are missing, a message ```No package 'foo' found``` will be
shown during the configure stage. See
<a href="https://who-t.blogspot.com.au/2014/05/configure-fails-with-no-package-foo.html">this blog post here</a>.
for instructions on how to fix it.

@subsection building_libwacom Building without libwacom

libwacom is required by libinput's tablet code to gather additional
information about tablets that is not available from the kernel device
itself. libwacom is required by default but can be skipped when @ref
building.

@code
$> meson --prefix=/usr -Dlibwacom=false builddir
@endcode

It is not recommended to disable libwacom unless libinput is used in an
environment where tablet support is not required. libinput provides tablet
support even without libwacom, but some features may be missing or working
differently.

@subsection building_debug_gui Building without the graphical helper tool

The @ref tools provide commandline features as well as graphical debugging
features. To keep dependencies in check on some builds, the graphical
features of the @ref tools can be disabled. By default, the `debug-gui`
feature of the `libinput` tool is enabled and if the required libraries are
not available, the build will fail. If the feature is not required, use the
``--disable-debug-gui`` argument when @ref building.

@code
$> meson --prefix=/usr -Ddebug-gui=false builddir
@endcode

@subsection building_autotools Building with autotools

<b>libinput no longer supports building with autotools.</b> These
instructions are kept for users for libinput versions up to 1.8.x.

A build with automake is usually the process below. A successful build
requires the @ref building_dependencies to be installed at configure
time.

@code
$> git clone git://anongit.freedesktop.org/git/wayland/libinput
$> cd libinput
$> ./autogen.sh --prefix=/usr --libdir=/usr/lib64
$> make
$> sudo make install
$> sudo udevadm hwdb --update
@endcode

@note On Debian-based distributions including Ubuntu and its derivatives skip the
```--libdir=/usr/lib64``` argument.

To uninstall libinput as detailed in section @ref reverting_install, run

@code
$> sudo make uninstall
# WARNING: Do not restart the computer/X/the Wayland compositor after make
# uninstall, reinstall the system package immediately!
@endcode

To disable libwacom as detailed in section @ref building_libwacom, run

@code
$> ./autogen.sh --disable-libwacom --prefix=/usr --libdir=/usr/lib64
@endcode

To disable the graphical helper tool as detailed in section @ref
building_debug_gui, run

@code
$> ./autogen.sh --disable-debug-gui --prefix=/usr --libdir=/usr/lib64
@endcode


@section building_against Building against libinput

libinput provides a
[pkg-config](https://www.freedesktop.org/wiki/Software/pkg-config/) file.
Software that uses libinput should use pkg-config and the
`PKG_CHECK_MODULES` autoconf macro.
Otherwise, the most rudimentary way to compile and link a program against
libinput is:

@code
    gcc -o myprogram myprogram.c `pkg-config --cflags --libs libinput`
@endcode

For further information on using pkgconfig see the pkg-config documentation.

*/