MarineComOS_RPI/README.md

# pi-gen

Tool used to create Raspberry Pi OS images, and custom images based on Raspberry Pi OS,
which was in turn derived from the Raspbian project.

**Note**: Raspberry Pi OS 32 bit images are based primarily on Raspbian, while
Raspberry Pi OS 64 bit images are based primarily on Debian.

**Note**: 32 bit images should be built from the `master` branch.
64 bit images should be built from the `arm64` branch.

## Dependencies

pi-gen runs on Debian-based operating systems released after 2017, and we
always advise you use the latest OS for security reasons.

On other Linux distributions it may be possible to use the Docker build described
below.

To install the required dependencies for `pi-gen` you should run:

```bash
apt-get install coreutils quilt parted qemu-user-static debootstrap zerofree zip \
dosfstools libarchive-tools libcap2-bin grep rsync xz-utils file git curl bc \
gpg pigz xxd arch-test
```

The file `depends` contains a list of tools needed.  The format of this
package is `<tool>[:<debian-package>]`.

## Getting started with building your images

Getting started is as simple as cloning this repository on your build machine. You
can do so with:

```bash
git clone https://github.com/RPI-Distro/pi-gen.git
```

`--depth 1` can be added afer `git clone` to create a shallow clone, only containing
the latest revision of the repository. Do not do this on your development machine.

Also, be careful to clone the repository to a base path **NOT** containing spaces.
This configuration is not supported by debootstrap and will lead to `pi-gen` not
running.

After cloning the repository, you can move to the next step and start configuring
your build.

## Config

Upon execution, `build.sh` will source the file `config` in the current
working directory.  This bash shell fragment is intended to set needed
environment variables.

The following environment variables are supported:

 * `IMG_NAME` (Default: `raspios-$RELEASE-$ARCH`, for example: `raspios-bookworm-armhf`)

   The name of the image to build with the current stage directories. Use this
   variable to set the root name of your OS, eg `IMG_NAME=Frobulator`.
   Export files in stages may add suffixes to `IMG_NAME`.

 * `PI_GEN_RELEASE` (Default: `Raspberry Pi reference`)

   The release name to use in `/etc/issue.txt`. The default should only be used
   for official Raspberry Pi builds.

* `RELEASE` (Default: `bookworm`)

   The release version to build images against. Valid values are any supported
   Debian release. However, since different releases will have different sets of
   packages available, you'll need to either modify your stages accordingly, or
   checkout the appropriate branch. For example, if you'd like to build a
   `bullseye` image, you should do so from the `bullseye` branch.

 * `APT_PROXY` (Default: unset)

   If you require the use of an apt proxy, set it here.  This proxy setting
   will not be included in the image, making it safe to use an `apt-cacher` or
   similar package for development.

 * `BASE_DIR`  (Default: location of `build.sh`)

   **CAUTION**: Currently, changing this value will probably break build.sh

   Top-level directory for `pi-gen`.  Contains stage directories, build
   scripts, and by default both work and deployment directories.

 * `WORK_DIR`  (Default: `$BASE_DIR/work`)

   Directory in which `pi-gen` builds the target system.  This value can be
   changed if you have a suitably large, fast storage location for stages to
   be built and cached.  Note, `WORK_DIR` stores a complete copy of the target
   system for each build stage, amounting to tens of gigabytes in the case of
   Raspbian.

   **CAUTION**: If your working directory is on an NTFS partition you probably won't be able to build: make sure this is a proper Linux filesystem.

 * `DEPLOY_DIR`  (Default: `$BASE_DIR/deploy`)

   Output directory for target system images and NOOBS bundles.

 * `DEPLOY_COMPRESSION` (Default: `zip`)

   Set to:
   * `none` to deploy the actual image (`.img`).
   * `zip` to deploy a zipped image (`.zip`).
   * `gz` to deploy a gzipped image (`.img.gz`).
   * `xz` to deploy a xzipped image (`.img.xz`).


 * `DEPLOY_ZIP` (Deprecated)

   This option has been deprecated in favor of `DEPLOY_COMPRESSION`.

   If `DEPLOY_ZIP=0` is still present in your config file, the behavior is the
   same as with `DEPLOY_COMPRESSION=none`.

 * `COMPRESSION_LEVEL` (Default: `6`)

   Compression level to be used when using `zip`, `gz` or `xz` for
   `DEPLOY_COMPRESSION`. From 0 to 9 (refer to the tool man page for more
   information on this. Usually 0 is no compression but very fast, up to 9 with
   the best compression but very slow ).

 * `USE_QEMU` (Default: `0`)

   Setting to '1' enables the QEMU mode - creating an image that can be mounted via QEMU for an emulated
   environment. These images include "-qemu" in the image file name.

 * `LOCALE_DEFAULT` (Default: 'en_GB.UTF-8' )

   Default system locale.

 * `TARGET_HOSTNAME` (Default: 'raspberrypi' )

   Setting the hostname to the specified value.

 * `KEYBOARD_KEYMAP` (Default: 'gb' )

   Default keyboard keymap.

   To get the current value from a running system, run `debconf-show
   keyboard-configuration` and look at the
   `keyboard-configuration/xkb-keymap` value.

 * `KEYBOARD_LAYOUT` (Default: 'English (UK)' )

   Default keyboard layout.

   To get the current value from a running system, run `debconf-show
   keyboard-configuration` and look at the
   `keyboard-configuration/variant` value.

 * `TIMEZONE_DEFAULT` (Default: 'Europe/London' )

   Default time zone.

   To get the current value from a running system, look in
   `/etc/timezone`.

 * `FIRST_USER_NAME` (Default: `pi`)

   Username for the first user. This user only exists during the image creation process. Unless
   `DISABLE_FIRST_BOOT_USER_RENAME` is set to `1`, this user will be renamed on the first boot with
   a name chosen by the final user. This security feature is designed to prevent shipping images
   with a default username and help prevent malicious actors from taking over your devices.

 * `FIRST_USER_PASS` (Default: unset)

   Password for the first user. If unset, the account is locked.

 * `DISABLE_FIRST_BOOT_USER_RENAME` (Default: `0`)

   Disable the renaming of the first user during the first boot. This make it so `FIRST_USER_NAME`
   stays activated. `FIRST_USER_PASS` must be set for this to work. Please be aware of the implied
   security risk of defining a default username and password for your devices.

 * `WPA_COUNTRY` (Default: unset)

   Sets the default WLAN regulatory domain and unblocks WLAN interfaces. This should be a 2-letter ISO/IEC 3166 country Code, i.e. `GB`

 * `ENABLE_SSH` (Default: `0`)

   Setting to `1` will enable ssh server for remote log in. Note that if you are using a common password such as the defaults there is a high risk of attackers taking over you Raspberry Pi.

  * `PUBKEY_SSH_FIRST_USER` (Default: unset)

   Setting this to a value will make that value the contents of the FIRST_USER_NAME's ~/.ssh/authorized_keys.  Obviously the value should
   therefore be a valid authorized_keys file.  Note that this does not
   automatically enable SSH.

  * `PUBKEY_ONLY_SSH` (Default: `0`)

   * Setting to `1` will disable password authentication for SSH and enable
   public key authentication.  Note that if SSH is not enabled this will take
   effect when SSH becomes enabled.

 * `SETFCAP` (Default: unset)

   * Setting to `1` will prevent pi-gen from dropping the "capabilities"
   feature. Generating the root filesystem with capabilities enabled and running
   it from a filesystem that does not support capabilities (like NFS) can cause
   issues. Only enable this if you understand what it is.

 * `STAGE_LIST` (Default: `stage*`)

    If set, then instead of working through the numeric stages in order, this list will be followed. For example setting to `"stage0 stage1 mystage stage2"` will run the contents of `mystage` before stage2. Note that quotes are needed around the list. An absolute or relative path can be given for stages outside the pi-gen directory.

 * `EXPORT_CONFIG_DIR` (Default: `$BASE_DIR/export-image`)

    If set, use this directory path as the location of scripts to run when generating images. An absolute or relative path can be given for a location outside the pi-gen directory.

A simple example for building Raspberry Pi OS:

```bash
IMG_NAME='raspios'
```

The config file can also be specified on the command line as an argument the `build.sh` or `build-docker.sh` scripts.

```
./build.sh -c myconfig
```

This is parsed after `config` so can be used to override values set there.

## How the build process works

The following process is followed to build images:

 * Interate through all of the stage directories in alphanumeric order

 * Bypass a stage directory if it contains a file called
   "SKIP"

 * Run the script ```prerun.sh``` which is generally just used to copy the build
   directory between stages.

 * In each stage directory iterate through each subdirectory and then run each of the
   install scripts it contains, again in alphanumeric order. **These need to be named
   with a two digit padded number at the beginning.**
   There are a number of different files and directories which can be used to
   control different parts of the build process:

     - **00-run.sh** - A unix shell script. Needs to be made executable for it to run.

     - **00-run-chroot.sh** - A unix shell script which will be run in the chroot
       of the image build directory. Needs to be made executable for it to run.

     - **00-debconf** - Contents of this file are passed to debconf-set-selections
       to configure things like locale, etc.

     - **00-packages** - A list of packages to install. Can have more than one, space
       separated, per line.

     - **00-packages-nr** - As 00-packages, except these will be installed using
       the ```--no-install-recommends -y``` parameters to apt-get.

     - **00-patches** - A directory containing patch files to be applied, using quilt.
       If a file named 'EDIT' is present in the directory, the build process will
       be interrupted with a bash session, allowing an opportunity to create/revise
       the patches.

  * If the stage directory contains files called "EXPORT_NOOBS" or "EXPORT_IMAGE" then
    add this stage to a list of images to generate

  * Generate the images for any stages that have specified them

It is recommended to examine build.sh for finer details.


## Docker Build

Docker can be used to perform the build inside a container. This partially isolates
the build from the host system, and allows using the script on non-debian based
systems (e.g. Fedora Linux). The isolation is not complete due to the need to use
some kernel level services for arm emulation (binfmt) and loop devices (losetup).

To build:

```bash
vi config         # Edit your config file. See above.
./build-docker.sh
```

If everything goes well, your finished image will be in the `deploy/` folder.
You can then remove the build container with `docker rm -v pigen_work`

If you encounter errors during the build, you can edit the corresponding scripts, and
continue:

```bash
CONTINUE=1 ./build-docker.sh
```

To examine the container after a failure you can enter a shell within it using:

```bash
sudo docker run -it --privileged --volumes-from=pigen_work pi-gen /bin/bash
```

After successful build, the build container is by default removed. This may be undesired when making incremental changes to a customized build. To prevent the build script from remove the container add

```bash
PRESERVE_CONTAINER=1 ./build-docker.sh
```

There is a possibility that even when running from a docker container, the
installation of `qemu-user-static` will silently fail when building the image
because `binfmt-support` _must be enabled on the underlying kernel_. An easy
fix is to ensure `binfmt-support` is installed on the host machine before
starting the `./build-docker.sh` script (or using your own docker build
solution).

### Passing arguments to Docker

When the docker image is run various required command line arguments are provided.  For example the system mounts the `/dev` directory to the `/dev` directory within the docker container.  If other arguments are required they may be specified in the PIGEN_DOCKER_OPTS environment variable.  For example setting `PIGEN_DOCKER_OPTS="--add-host foo:192.168.0.23"` will add '192.168.0.23   foo' to the `/etc/hosts` file in the container.  The `--name`
and `--privileged` options are already set by the script and should not be redefined.

## Stage Anatomy

### Raspbian Stage Overview

The build of Raspbian is divided up into several stages for logical clarity
and modularity.  This causes some initial complexity, but it simplifies
maintenance and allows for more easy customization.

 - **Stage 0** - bootstrap.  The primary purpose of this stage is to create a
   usable filesystem.  This is accomplished largely through the use of
   `debootstrap`, which creates a minimal filesystem suitable for use as a
   base.tgz on Debian systems.  This stage also configures apt settings and
   installs `raspberrypi-bootloader` which is missed by debootstrap.  The
   minimal core is installed but not configured. As a result, this stage will not boot.

 - **Stage 1** - truly minimal system.  This stage makes the system bootable by
   installing system files like `/etc/fstab`, configures the bootloader, makes
   the network operable, and installs packages like raspi-config.  At this
   stage the system should boot to a local console from which you have the
   means to perform basic tasks needed to configure and install the system.

 - **Stage 2** - lite system.  This stage produces the Raspberry Pi OS Lite image.
   Stage 2 installs some optimized memory functions, sets timezone and charmap
   defaults, installs fake-hwclock and ntp, wireless LAN and bluetooth support,
   dphys-swapfile, and other basics for managing the hardware.  It also
   creates necessary groups and gives the pi user access to sudo and the
   standard console hardware permission groups.

   Note: Raspberry Pi OS Lite contains a number of tools for development,
   including `Python`, `Lua` and the `build-essential` package. If you are
   creating an image to deploy in products, be sure to remove extraneous development
   tools before deployment.

 - **Stage 3** - desktop system.  Here's where you get the full desktop system
   with X11 and LXDE, web browsers, git for development, Raspberry Pi OS custom UI
   enhancements, etc.  This is a base desktop system, with some development
   tools installed.

 - **Stage 4** - Normal Raspberry Pi OS image. System meant to fit on a 4GB card.
   This is the    stage that installs most things that make Raspberry Pi OS friendly
   to new users - e.g. system documentation.

 - **Stage 5** - The Raspberry Pi OS Full image. More development
   tools, an email client, learning tools like Scratch, specialized packages
   like sonic-pi, office productivity, etc.

### Stage specification

If you wish to build up to a specified stage (such as building up to stage 2
for a lite system), place an empty file named `SKIP` in each of the `./stage`
directories you wish not to include.

Then add an empty file named `SKIP_IMAGES` to `./stage4` and `./stage5` (if building up to stage 2) or
to `./stage2` (if building a minimal system).

```bash
# Example for building a lite system
echo "IMG_NAME='raspios'" > config
touch ./stage3/SKIP ./stage4/SKIP ./stage5/SKIP
touch ./stage4/SKIP_IMAGES ./stage5/SKIP_IMAGES
sudo ./build.sh  # or ./build-docker.sh
```

If you wish to build further configurations upon (for example) the lite
system, you can also delete the contents of `./stage3` and `./stage4` and
replace with your own contents in the same format.


## Skipping stages to speed up development

If you're working on a specific stage the recommended development process is as
follows:

 * Add a file called SKIP_IMAGES into the directories containing EXPORT_* files
   (currently stage2, stage4 and stage5)
 * Add SKIP files to the stages you don't want to build. For example, if you're
   basing your image on the lite image you would add these to stages 3, 4 and 5.
 * Run build.sh to build all stages
 * Add SKIP files to the earlier successfully built stages
 * Modify the last stage
 * Rebuild just the last stage using ```sudo CLEAN=1 ./build.sh``` (or, for docker builds
   ```PRESERVE_CONTAINER=1 CONTINUE=1 CLEAN=1 ./build-docker.sh```)
 * Once you're happy with the image you can remove the SKIP_IMAGES files and
   export your image to test

# Troubleshooting

## `64 Bit Systems`
Please note there is currently an issue when compiling with a 64 Bit OS. See
https://github.com/RPi-Distro/pi-gen/issues/271

A 64 bit image can be generated from the `arm64` branch in this repository. Just
replace the command from [this section](#getting-started-with-building-your-images)
by the one below, and follow the rest of the documentation:
```bash
git clone --branch arm64 https://github.com/RPI-Distro/pi-gen.git
```

If you want to generate a 64 bits image from a Raspberry Pi running a 32 bits
version, you need to add `arm_64bit=1` to your `config.txt` file and reboot your
machine. This will restart your machine with a 64 bits kernel. This will only
work from a Raspberry Pi with a 64-bit capable processor (i.e. Raspberry Pi Zero
2, Raspberry Pi 3 or Raspberry Pi 4).


## `binfmt_misc`

Linux is able execute binaries from other architectures, meaning that it should be
possible to make use of `pi-gen` on an x86_64 system, even though it will be running
ARM binaries. This requires support from the [`binfmt_misc`](https://en.wikipedia.org/wiki/Binfmt_misc)
kernel module.

You may see one of the following errors:

```
update-binfmts: warning: Couldn't load the binfmt_misc module.
```
```
W: Failure trying to run: chroot "/pi-gen/work/test/stage0/rootfs" /bin/true
and/or
chroot: failed to run command '/bin/true': Exec format error
```

To resolve this, ensure that the following files are available (install them if necessary):

```
/lib/modules/$(uname -r)/kernel/fs/binfmt_misc.ko
/usr/bin/qemu-arm-static
```

You may also need to load the module by hand - run `modprobe binfmt_misc`.

If you are using WSL to build you may have to enable the service `sudo update-binfmts --enable`