## SerenityOS build instructions

### Linux prerequisites
Make sure you have all the dependencies installed:

**Debian / Ubuntu**
```bash
sudo apt install build-essential cmake curl libmpfr-dev libmpc-dev libgmp-dev e2fsprogs qemu-system-i386 qemu-utils
```

On Docker, install these as well:
```bash
sudo apt install wget genext2fs
```

**Fedora**
```bash
sudo dnf install curl cmake mpfr-devel libmpc-devel gmp-devel e2fsprogs @"C Development Tools and Libraries" @Virtualization
```

**Arch Linux / Manjaro**
```bash
sudo pacman -S base-devel cmake curl mpfr libmpc gmp e2fsprogs qemu qemu-arch-extra
```

Ensure your gcc version is >= 8 with `gcc --version`. Otherwise, install it (on Ubuntu) with:
```bash
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get install gcc-9 g++-9
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-9 900 --slave /usr/bin/g++ g++ /usr/bin/g++-9
```

### macOS prerequisites
Make sure you have all the dependencies installed:
```bash
brew install coreutils
brew tap discoteq/discoteq
brew install flock
brew install qemu
brew install wget
brew install e2fsprogs
brew install m4
brew install autoconf
brew install libtool
brew install automake
brew cask install osxfuse
Toolchain/BuildFuseExt2.sh
```

Notes: 
- fuse-ext2 is not available as brew formula so it must be installed using `BuildFuseExt2.sh`
- Xcode and `xcode-tools` must be installed (`git` is required by some scripts)
- coreutils is needed to build gcc cross compiler
- `flock` command can also be installed with `brew install util-linux` but in that case you will need to add it to `$PATH`
- qemu is needed to run the compiled OS image. You can also build it using the `BuildQemu.sh` script
- osxfuse, e2fsprogs, m4, autoconf, automake, libtool and `BuildFuseExt2.sh` are needed if you want to build the root filesystem disk image natively on macOS. This allows mounting an EXT2 fs and also installs commands like `mke2fs` that are not available on stock macOS. 
- If you install some commercial EXT2 macOS fs handler instead of osxfuse and fuse-ext2, you will need to `brew install e2fsprogs` to obtain `mke2fs` anyway.

### OpenBSD prerequisites
```
pkg_add bash gmp gcc git flock gmake sudo
```

### Build
> Before starting, make sure that you have configured your global identity for git, or the first script will fail after running for a bit.

Go into the `Toolchain/` directory and run the **BuildIt.sh** script.

Once you've built the toolchain, create a directory for the build to live in (for example, `Build/`), and run the CMake build:
```
$ mkdir Build && cd Build
$ cmake ..
$ make
$ make install
```

This will compile all of SerenityOS and install the built files into `Root/` inside the build tree. `make install` actually pulls in the regular `make` (`make all`) automatically, so there isn't really a need to run it exlicitly. You may also want ask `make` to build things in parallel by using `-j`, optionally specifying the maximum number of jobs to run.

Now to build a disk image, run `make image`, and if nothing breaks too much, take it for a spin by using `make run`.

Note that the `anon` user is able to become `root` without password by default, as a development convenience.
To prevent this, remove `anon` from the `wheel` group and he will no longer be able to run `/bin/su`.

On Linux, QEMU is significantly faster if it's able to use KVM. The run script will automatically enable KVM if `/dev/kvm` exists and is readable+writable by the current user.

Bare curious users may even consider sourcing suitable hardware to [install Serenity on a physical PC.](https://github.com/SerenityOS/serenity/blob/master/INSTALL.md)

Later on, when you `git pull` to get the latest changes, there's no need to rebuild the toolchain. You can simply run `make install`, `make image`, `make run` again. CMake will only rebuild those parts that have been updated.

You may also want to replace `make` with `ninja` in the above (use `cmake .. -G Ninja` when configuring the build) for some additional build speed benefits.

#### Ports
To add a package from the ports collection to Serenity, for example curl, go into `Ports/curl/` and run **./package.sh**. The sourcecode for the package will be downloaded and the package will be built. After that, run **./sync.sh** from the `Kernel/` directory to update the disk image. The next time you start Serenity with **./run**, `curl` will be available.