Build Falco from source

Build Falco or its libraries yourself from the source code

Welcome to the guide on how to build Falco yourself! You are very brave! Since you are already doing all this, chances that you are willing to contribute are high! Please read our contributing guide.

  1. Install the dependencies

CentOS 8 Stream / RHEL 8

dnf install git gcc gcc-c++ git make cmake elfutils-libelf-devel perl-IPC-Cmd

apt update && apt install git cmake build-essential libelf-dev

pacman -S git cmake make gcc wget
pacman -S zlib jq yaml-cpp openssl curl c-ares protobuf grpc libyaml

You'll also need kernel headers for building and making binaries properly.

pacman -S linux-headers

You can use uname -r to determine the kernel version and select the appropriate header.

Since Alpine ships with musl instead of glibc, to build on Alpine, we need to pass the -DMUSL_OPTIMIZED_BUILD=On CMake option.

If that option is used along with the -DUSE_BUNDLED_DEPS=On option, then the final build will be 100% statically-linked and portable across different Linux distributions.

apk add g++ gcc cmake make git bash perl linux-headers autoconf automake m4 libtool elfutils-dev libelf-static binutils bpftool clang

zypper -n install git gcc12 gcc12-c++ cmake make libelf-devel gawk
  1. Build Falco

git clone https://github.com/falcosecurity/falco.git
cd falco
mkdir -p build
cd build
cmake -DUSE_BUNDLED_DEPS=ON ..
make falco

More details here.

git clone https://github.com/falcosecurity/falco.git
cd falco
mkdir -p build
cd build
cmake -DUSE_BUNDLED_DEPS=On ..
make falco

More details here.

git clone https://github.com/falcosecurity/falco.git
cd falco
mkdir -p build
cd build
cmake ..
make falco

More details here.

git clone https://github.com/falcosecurity/falco.git
cd falco
mkdir -p build
cd build
cmake -DUSE_BUNDLED_DEPS=On -DMUSL_OPTIMIZED_BUILD=On ..
make falco

First, make sure that gcc and g++ are version 9 or above. If you have multiple versions installed you can set the preferred one.

git clone https://github.com/falcosecurity/falco.git
cd falco
mkdir -p build
cd build
cmake -DUSE_BUNDLED_DEPS=ON ..
make falco

More details here.

  1. Build kernel module driver

In the build directory:

yum -y install kernel-devel-$(uname -r)
make driver

More details here.

Kernel headers are required to build the driver.

apt install linux-headers-$(uname -r)

In the build directory:

make driver

In the build directory:

pacman -S --needed linux-headers
make driver

More details here.

NO STEP

In the build directory:

zypper -n install kernel-default-devel
make driver
  1. Build eBPF driver (optional)

If you do not want to use the kernel module driver you can, alternatively, build the eBPF driver as follows.

In the build directory:

dnf install clang llvm
cmake -DBUILD_BPF=ON ..
make bpf

If you do not want to use the kernel module driver you can, alternatively, build the eBPF driver as follows.

In the build directory:

apt install llvm clang
cmake -DBUILD_BPF=ON ..
make bpf

If you do not want to use the kernel module driver you can, alternatively, build the eBPF driver as follows.

In the build directory:

pacman -S llvm clang
cmake -DBUILD_BPF=ON ..
make bpf

NO STEP

If you do not want to use the kernel module driver you can, alternatively, build the eBPF driver as follows.

In the build directory:

zypper -n install clang llvm
cmake -DBUILD_BPF=ON ..
make bpf

Dependencies

By default Falco build bundles most of its runtime dependencies dynamically.

You can notice this observing that the option USE_BUNDLED_DEPS is OFF by default. Which means that, whether applicable, Falco build will try to link against libraries already existing into your machine.

Changing such option to ON causes Falco build to bundle all the dependencies statically.

Build Falco

To build Falco, you will need to create a build directory. It's common to have the build directory in the Falco working copy itself, however it can be anywhere in your filesystem.

There are three main steps to compile Falco.

  1. Create the build directory and enter in it
  2. Use cmake in the build directory to create the build files for Falco. .. was used because the source directory is a parent of the current directory, you can also use the absolute path for the Falco source code instead
  3. Build using make

Build all

mkdir build
cd build
cmake ..
make

You can also build only specific targets:

Build Falco only

Do the build folder and cmake setup, then:

make falco

Build the Falco engine only

Do the build folder and cmake setup, then:

make falco_engine

Build libscap only

Do the build folder and cmake setup, then:

make scap

Build libsinsp only

Do the build folder and cmake setup, then:

make sinsp

Build the eBPF probe / kernel driver only

Do the build folder and cmake setup, then:

make driver

Build results

Once Falco is built, the three interesting things that you will find in your build folder are:

  • userspace/falco/falco: the actual Falco binary
  • driver/src/falco.ko: the Falco kernel driver
  • driver/bpf/falco.o: if you built Falco with eBPF support

If you'd like to build a debug version, run cmake as cmake -DCMAKE_BUILD_TYPE=Debug .. instead, see the CMake Options section for further customizations.

CMake Options

When doing the cmake command, we can pass additional parameters to change the behavior of the build files.

Here'are some examples, always assuming your build folder is inside the Falco working copy.

Generate verbose makefiles

-DCMAKE_VERBOSE_MAKEFILE=On

Specify C and CXX compilers

-DCMAKE_C_COMPILER=$(which gcc) -DCMAKE_CXX_COMPILER=$(which g++)

Enforce bundled dependencies

-DUSE_BUNDLED_DEPS=True

Read more about Falco dependencies here.

Treat warnings as errors

-DBUILD_WARNINGS_AS_ERRORS=True

Specify the build type

Debug build type

-DCMAKE_BUILD_TYPE=Debug

Release build type

-DCMAKE_BUILD_TYPE=Release

Notice this variable is case-insensitive and it defaults to release.

Specify the Falco version

Optionally the user can specify the version he wants Falco to have. Eg.,

 -DFALCO_VERSION=0.38.0-dirty

When not explicitly specifying it the build system will compute the FALCO_VERSION value from the git history.

In case the current git revision has a git tag, the Falco version will be equal to it (without the leading "v" character). Otherwise the Falco version will be in the form 0.<commit hash>[.dirty].

Enable eBPF support

-DBUILD_BPF=True

When enabling this you will be able to make the bpf target after:

make bpf

Load latest falco kernel module

If you have a binary version of Falco installed, an older Falco kernel module may already be loaded. To ensure you are using the latest version, you should unload any existing Falco kernel module and load the locally built version.

Unload any existing kernel module via:

rmmod falco

To load the locally built version, assuming you are in the build dir, use:

insmod driver/falco.ko

Run falco

Once Falco is built and the kernel module is loaded, assuming you are in the build dir, you can run falco as:

sudo ./userspace/falco/falco -c ../falco.yaml -r ../rules/falco_rules.yaml

By default, falco logs events to standard error.