## SerenityOS build instructions

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

**Debian / Ubuntu**
```bash
sudo apt install build-essential 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 mpfr-devel libmpc-devel gmp-devel e2fsprogs @"C Development Tools and Libraries" @Virtualization
```

**Arch Linux / Manjaro**
```bash
sudo pacman -S base-devel 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
```

When building with `make`, `gmake` must be used.  The `makeall.sh` script will do this automatically when building on OpenBSD.

### 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, go into the `Kernel/` directory, then run
**./makeall.sh**, and if nothing breaks too much, take it for a spin by using
**./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 rerun **./makeall.sh** in the `Kernel/` directory and you'll be good to **./run** again.

You can even re-compile only parts of the system. Imagine you changed something in the **WindowServer**. Then run `make -C ../Services/WindowServer` (from the `Kernel/` directory) followed by **./sync.sh** to update the disk image. Then you can start the system with **./run** again.

#### 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.