Linux build preparation¶
They aren’t complicated, but there are a few prerequisites to building Firefox on Linux. You need:
A 64-bit installation of Linux. You can check by opening a terminal window; if
x86_64you can proceed.
Next, you’ll need Python 2.7 and Python 3.x installed. You can check with
python --versionto see if you have it already.If not, you can install it with your distribution’s package manager. Make sure your system is up to date!
Finally, a reasonably fast internet connection and 30GB of free disk space.
Getting set up on Linux is fast and easy.
If you don’t have one yet, create a “
src” directory for
yourself under your home directory:
mkdir src && cd src
Next download the bootstrap.py
and save it in the
src/ directory created above.
Building Firefox in Linux on top of a non-native file system - for example, on a mounted NTFS partition - is explicitly not supported. While a build environment like this may succeed it may also fail while claiming to have succeeded, which can be quite difficult to diagnose and fix.
And finally, in your terminal from above start the bootstrapper like this:
… and follow the prompts. This will use mercurial to checkout the source code. If you prefer to work with git, use this command instead:
python bootstrap.py --vcs=git
Bugzilla is Mozilla’s issue tracker; you’ll need to be able to log into it to comment on a bug or submit a patch. You can either use your GitHub account, or you can sign up for a Bugzilla account here.
As well as Bugzilla, much of Mozilla’s internal communication happens over Riot/Matrix. The instance is available on https://chat.mozilla.org/.
If you’re just getting started or have questions about getting set up you can join us in the #introduction channel, where some of our community members hang out to try and help new contributors get rolling.
Let’s Build Firefox¶
You’re ready; now we can tie it all together. In your terminal:
# Automatically download and use compiled C++ components: # This option will disable C/C++ compilation ac_add_options --enable-artifact-builds # Write build artifacts to (not mandatory): mk_add_options MOZ_OBJDIR=./objdir-frontend
If you plan to walk through code with a debugger, set up a .mozconfig file with the following options:
ac_add_options --disable-optimize ac_add_options --enable-debug
Older clang versions (especially clang 6) from LTS linux
distributions sometimes miscompile
resulting in startup crashes when starting the resulting build.
If this happens, you can force the use of the
./mach bootstrap downloaded by adding the following to
export CC=path/to/home/.mozbuild/clang/bin/clang export CXX=path/to/home/.mozbuild/clang/bin/clang++
And finally, run the build command:
If you encounter any error related to LLVM/Clang on Ubuntu or
Debian, download the latest version of LLVM and Clang and then
And you’re on your way, building your own copy of Firefox from
source. Don’t be discouraged if this takes a while; this takes
some time on even the fastest modern machines, and as much as two
hours or more on older hardware. When the
--enable-artifact-builds option is used, builds usually finish
within a few minutes.
Now the fun starts¶
You have the code, you’ve compiled Firefox. Fire it up with
./mach run and you’re ready to start hacking. The next steps
are up to you: join us on IRC in the
and find a bug to start working
2GB RAM with an additional 2GB of available swap space is the bare minimum, and more RAM is always better - having 8GB or more will dramatically improve build time.
A 64-bit x86 CPU and a 64-bit OS. As of early 2015 it is no longer possible to do a full build of Firefox from source on most 32-bit systems; a 64-bit OS is required. “Artifact builds” may be possible, but are not a supported configuration. On Linux you can determine this by typing “
uname -a” in a terminal.
A recent version of Clang is required to build Firefox. You can learn more about the features we use and their compiler support here
Most Linux distros now install a later version of autoconf, which the build system cannot use, reporting the error “
*** Couldn't find autoconf 2.13. Stop.” However a separate
autoconf2.13package is usually available. To install autoconf 2.13 in Debian based distros copy this line and paste it into a terminal window:
$ sudo apt install autoconf2.13
If you are on a Fedora machine then simply install the following prerequisites from the terminal window:
sudo dnf install @development-tools @c-development autoconf213 gtk2-devel gtk3-devel libXt-devel GConf2-devel dbus-glib-devel yasm-devel alsa-lib-devel pulseaudio-libs-devel
Requirements for Debian / Ubuntu users¶
You need a number of different packages:
# the rust compiler aptitude install rustc # the rust package manager aptitude install cargo # the required (old) version of autoconf aptitude install autoconf2.13 # the headers of important libs aptitude install libgtk-2-dev aptitude install libgtk-3-dev aptitude install libgconf2-dev aptitude install libdbus-glib-1-dev aptitude install libpulse-dev # rust dependencies cargo install cbindgen # an assembler for compiling webm aptitude install yasm
Our system bootstrapping script can automatically install the required dependencies. You can download and run it by copying this line and pasting it into a terminal window:
wget -q https://hg.mozilla.org/mozilla-central/raw-file/default/python/mozboot/bin/bootstrap.py -O bootstrap.py && python bootstrap.py
Note: piping bootstrap.py to stdin of a python process will cause interactive prompts in the bootstrap script to fail, causing the bootstrap process to fail. You must run Python against a local file.
If the above command fails, the reason is often because some Linux distributions ship with an outdated list of root certificates. In this case, you should upgrade your Linux distribution or use your browser to download the file. That ensures that you will get it from the right source. If you get an error from this process, consider filing a bug saying that the bootstrapper didn’t work and contact Mike Hoye directly for help. Please include the error message and some details about your operating system.
If you have already checked out the source code via Mercurial or Git you can also use mach with the bootstrap command:
Common Bootstrapper Failures¶
wget: command not found
You may not have wget (or curl) installed. In that case, you can either install it via your package manager:
On Debian-based distros like Ubuntu:
sudo apt install wget
On Fedora-based distros:
sudo dnf install wget
or you can just download bootstrap.py using your browser and then run it with this command:
In some cases people who’ve customized their command prompt to include
emoji or other non-text symbols have found that bootstrap.py fails with
UnicodeDecodeError. We have a bug filed for that but in the
meantime if you run into this problem you’ll need to change your prompt
back to something boring.