Build Instructions

You must be running a 64-bit x86 Linux distribution. Darling cannot be used on a 32-bit x86 system, not even to run 32-bit applications.

Dependencies

It is recommended that you use at least Clang 3.8. You can force a specific version of Clang (if it is installed on your system) by editing Toolchain.cmake.

Linux 4.19 or higher is required.

Debian 10

$ sudo apt install cmake clang-6.0 bison flex xz-utils libfuse-dev libudev-dev pkg-config \
libc6-dev-i386 linux-headers-amd64 libcap2-bin git python2 libglu1-mesa-dev libcairo2-dev \
libgl1-mesa-dev libtiff5-dev libfreetype6-dev libxml2-dev libegl1-mesa-dev libfontconfig1-dev \
libbsd-dev libxrandr-dev libxcursor-dev libgif-dev libpulse-dev libavformat-dev libavcodec-dev \
libavresample-dev libdbus-1-dev libxkbfile-dev

Debian Testing

$ sudo apt install cmake clang-9 bison flex xz-utils libfuse-dev libudev-dev pkg-config \
libc6-dev-i386 linux-headers-amd64 libcap2-bin git python2 libglu1-mesa-dev libcairo2-dev \
libgl1-mesa-dev libtiff5-dev libfreetype6-dev libxml2-dev libegl1-mesa-dev libfontconfig1-dev \
libbsd-dev libxrandr-dev libxcursor-dev libgif-dev libpulse-dev libavformat-dev libavcodec-dev \
libavresample-dev libdbus-1-dev libxkbfile-dev

Ubuntu 18.04/20.04:

$ sudo apt install cmake clang bison flex libfuse-dev libudev-dev pkg-config libc6-dev-i386 \
linux-headers-generic gcc-multilib libcairo2-dev libgl1-mesa-dev libglu1-mesa-dev libtiff5-dev \
libfreetype6-dev git libelf-dev libxml2-dev libegl1-mesa-dev libfontconfig1-dev libbsd-dev \
libxrandr-dev libxcursor-dev libgif-dev libavutil-dev libpulse-dev libavformat-dev libavcodec-dev \
libavresample-dev libdbus-1-dev libxkbfile-dev

For Ubuntu 20.04, also install python2.

Arch Linux & Manjaro:

libavresample needs to be downloaded from the AUR.

$ sudo pacman -S --needed make cmake clang flex bison icu fuse linux-headers gcc-multilib \
lib32-gcc-libs pkg-config fontconfig cairo libtiff python2 mesa llvm libbsd libxkbfile \ 
libxcursor libxext libxkbcommon libxrandr

Make sure you install the headers package that matches your kernel version. The kernel version can be checked with uname -r.

$ uname -r
5.4.6-2-MANJARO

Then you should have linux54-headers installed. You will typically be prompted but may have to install this manually.

Fedora and CentOS

RPMFusion is required for FFmpeg.

$ sudo dnf install make cmake clang bison dbus-devel flex python2 glibc-devel.i686 fuse-devel \
systemd-devel kernel-devel elfutils-libelf-devel cairo-devel freetype-devel.{x86_64,i686} \
libjpeg-turbo-devel.{x86_64,i686} libtiff-devel.{x86_64,i686} fontconfig-devel.{x86_64,i686} \
libglvnd-devel.{x86_64,i686} mesa-libGL-devel.{x86_64,i686} mesa-libEGL-devel.{x86_64,i686} \
libxml2-devel libbsd-devel git libXcursor-devel libXrandr-devel giflib-devel ffmpeg-devel \
pulseaudio-libs-devel libxkbfile-devel

Fetch the Sources

Darling makes extensive use of Git submodules, therefore you cannot use a plain git clone. Make a clone like this:

$ git clone --recursive https://github.com/darlinghq/darling.git

Attention: The source tree requires up to 4 GB of disk space!

Updating sources

If you have already cloned Darling and would like to get the latest changes, do this in the source root:

$ git pull
$ git submodule init
$ git submodule update

Build

The build system of Darling is CMake. Makefiles are generated by CMake by default.

Attention: The build may require up to 10 GB of disk space! The Darling installation itself then takes up to 1 GB.

Building and Installing

Now let's build Darling:

# Move into the cloned sources
$ cd darling

# Make a build directory
$ mkdir build && cd build

# Configure the build
$ cmake ..

# Build and install Darling
$ make
$ sudo make install

Darling also requires a kernel module named darling-mach:

$ make lkm
$ sudo make lkm_install

If module installation produces warnings such as SSL error:02001002:system library:fopen:No such file or directory: bss_file.c:175, then these can be usually ignored, unless you configured your system to enforce secure boot.

The kernel module is an experimental piece of code; it's likely to have many bugs and vulnerabilities. Be prepared for kernel hangups and crashes, and run Darling on a virtual machine if possible.

Build Options

You will notice that it takes a long time to build Darling. Darling contains the software layer equivalent to an entire operating system, which means a large amount of code. You can optionally disable some large and less vital parts of the build in order to get faster builds.

To do this, use the -DFULL_BUILD=OFF option when configuring Darling through CMake.

You may encounter some things to be missing, such as JavaScriptCore. Before creating an issue about a certain library or framework missing from Darling, verify that you are doing a full build by not using this option or setting it to ''ON''.

Another way to speed up the build is to run make with multiple jobs. For this, run make -j8 instead, where 8 is a number of current jobs to run of your choosing. In general, avoid running more jobs than twice the amount CPU cores of your machine.

If you run LLDB and encounter messages indicating a lack of debug symbols, make sure you are doing a debug build. To do this, use the -DCMAKE_BUILD_TYPE=Debug.

Known Issues

BackBox

If your distribution is Backbox and you run into build issues try the following commands:

sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-4.0 400
sudo update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-4.0 400

SELinux

On SELinux you may see the following error when starting Darling:

Cannot open mnt namespace file: No such file or directory

To work around this try this command: setsebool -P mmap_low_allowed 1.

Secure Boot

If Secure Boot is enabled you may see:

modprobe: ERROR: could not insert 'darling_mach': Operation not permitted
Failed to load the kernel module

Use the following commands to generate a key and self-sign the kernel module:

# Generate Key
openssl req -new -x509 -newkey rsa:2048 -keyout MOK.priv -outform DER -out MOK.der -nodes -days 36500 -subj "/CN=Darling LKM/"
# Enroll Key
sudo mokutil --import MOK.der
# Sign Module
sudo kmodsign sha512 MOK.priv MOK.der /lib/modules/$(uname -r)/extra/darling-mach.ko
# Reboot System and Enroll Key

No rule to make target 'modules'

This error can occur for a number of reasons. The most common is that your currently running kernel is no longer installed, which occurs after an upgrade. Before trying other steps reboot your system in order to test against this.

Another cause is that the kernel headers may not be installed. Distributions such as Ubuntu will install the correct headers automatically, but Arch/Manjaro may require you to install the appropriate headers manually. See the "Arch Linux & Manjaro" section earlier on this page for instructions on how to install the appropriate Linux headers.

make -C /lib/modules/5.4.2-1-MANJARO/build M=/home/xeab/Downloads/darling/src/lkm modules
make[5]: Entering directory '/usr/lib/modules/5.4.2-1-MANJARO/build'
make[5]: *** No rule to make target 'modules'.  Stop.

File System Support

Darling uses overlayfs for implementing prefixes on top of the macOS-like root filesystem. While overlayfs is not very picky about the lower (read-only) filesystem (where your /usr lives), it has stricter requirements for the upper filesystem (your home directory, unless you override the DPREFIX environment variable).

To quote the kernel documentation:

The lower filesystem can be any filesystem supported by Linux and does not need to be writable. The lower filesystem can even be another overlayfs. The upper filesystem will normally be writable and if it is it must support the creation of trusted.* extended attributes, and must provide valid d_type in readdir responses, so NFS is not suitable.

In addition to NFS not being supported, ZFS is also known not to work.

If you try to use an unsupported file system, this error will be printed:

Cannot mount overlay: Invalid argument