# Preparing to Use the Application Development Toolkit (ADT)

In order to use the ADT, you must install it, `source` a script to set up the environment, and be sure both the kernel and filesystem image specific to the target architecture exist.

This chapter describes two important terms and how to be sure you meet the ADT requirements.

## Yocto Project Files and Build Areas

Before learning how to prepare your system for the ADT, you need to understand two important terms used throughout this manual:

- The Yocto Project Files: This term refers to the directory structure created as a result of downloading and unpacking a Yocto Project release tarball or setting up a Git repository by cloning `git://git.yoctoproject.org/poky`.

  The Yocto Project files contain BitBake, Documentation, metadata and other files that all support the development environment. Consequently, you must have the Yocto Project files in place on your development system in order to do any development using the Yocto Project.

  The name of the top-level directory of the Yocto Project file structure is derived from the Yocto Project release tarball. For example, downloading and unpacking `poky-edison-6.0.tar.bz2` results in a Yocto Project source tree whose Yocto Project source directory is named `poky-edison-6.0`. If you create a Git repository, then you can name the repository anything you like.

  You can find instruction on how to set up the Yocto Project files on your host development system by reading the Getting Setup section in The Yocto Project Development Manual.

- Yocto Project Build Tree: This term refers to the area where the Yocto Project builds images. The area is created when you `source` the Yocto Project setup environment script that is found in the Yocto Project files area. (e.g. `oe-init-build-env`). You can create the Yocto Project build tree anywhere you want on your development system. Here is an example that creates the tree in `mybuilds` and names the Yocto Project build directory `YP-6.0`:

           $ source poky-edison-6.0/oe-init-build-env $HOME/mybuilds/YP-6.0

  If you don't specifically name the build directory, then BitBake creates it in the current directory and uses the name `build`. Also, if you supply an existing directory, then BitBake uses that directory as the Yocto Project build directory and populates the build tree beneath it.

## Installing the ADT

The following list describes how you can install the ADT, which includes the cross-toolchain. Regardless of the installation you choose, you must `source` the cross-toolchain environment setup script before you use the toolchain. See the "Setting Up the Environment" section for more information.

- Use the ADT Installer Script: This method is the recommended way to install the ADT because it automates much of the process for you. For example, you can configure the installation to install the QEMU emulator and the user-space NFS, specify which root filesystem profiles to download, and define the target sysroot location.

- Use an Existing Toolchain Tarball: Using this method, you select and download an architecture-specific toolchain tarball and then hand-install the toolchain. If you use this method, you just get the cross-toolchain and QEMU - you do not get any of the other mentioned benefits had you run the ADT Installer script.

- Use the Toolchain from within a Yocto Project Build Tree: If you already have a Yocto Project build tree, you can install the cross-toolchain using that tree. However, like the previous method mentioned, you only get the cross-toolchain and QEMU - you do not get any of the other benefits without taking separate steps.

### Using the ADT Installer

To run the ADT Installer, you need to first get the ADT Installer tarball and then run the ADT Installer Script.

#### Getting the ADT Installer Tarball

The ADT Installer is contained in the ADT Installer tarball. You can download the tarball into any directory from . Or, you can use BitBake to generate the tarball inside the existing Yocto Project build tree.

If you use BitBake to generate the ADT Installer tarball, you must `source` the Yocto Project environment setup script located in the Yocto Project file structure before running the `bitbake` command that creates the tarball.

The following example commands download the Yocto Project release tarball, set up the Yocto Project files structure, set up the environment while also creating the default Yocto Project build tree, and run the `bitbake` command that results in the tarball `~/yocto-project/build/tmp/deploy/sdk/adt_installer.tar.bz2`:

         $ cd ~
         $ mkdir yocto-project
         $ cd yocto-project
         $ wget http://www.yoctoproject.org/downloads/poky/poky-edison-6.0.tar.bz2
         $ tar xjf poky-edison-6.0.tar.bz2
         $ source poky-edison-6.0/oe-init-build-env
         $ bitbake adt-installer

#### Configuring and Running the ADT Installer Script

Before running the ADT Installer script, you need to unpack the tarball. You can unpack the tarball in any directory you wish. Unpacking it creates the directory `adt-installer`, which contains the ADT Installer script (`adt_installer`) and its configuration file (`adt_installer.conf`).

Before you run the script, however, you should examine the ADT Installer configuration file and be sure you are going to get what you want. Your configurations determine which kernel and filesystem image are downloaded.

The following list describes the configurations you can define for the ADT Installer. For configuration values and restrictions, see the comments in the `adt-installer.conf` file:

- `YOCTOADT_REPO`: This area includes the IPKG-based packages and the root filesystem upon which the installation is based. If you want to set up your own IPKG repository pointed to by `YOCTOADT_REPO`, you need to be sure that the directory structure follows the same layout as the reference directory set up at . Also, your repository needs to be accessible through HTTP.

- `YOCTOADT_TARGETS`: The machine target architectures for which you want to set up cross-development environments.

- `YOCTOADT_QEMU`: Indicates whether or not to install the emulator QEMU.

- `YOCTOADT_NFS_UTIL`: Indicates whether or not to install user-mode NFS. If you plan to use the Yocto Eclipse IDE plug-in against QEMU, you should install NFS.

  To boot QEMU images using our userspace NFS server, you need to be running `portmap` or `rpcbind`. If you are running `rpcbind`, you will also need to add the `-i` option when `rpcbind` starts up. Please make sure you understand the security implications of doing this. You might also have to modify your firewall settings to allow NFS booting to work.

- `YOCTOADT_ROOTFS_<arch>`: The root filesystem images you want to download from the `YOCTOADT_IPKG_REPO` repository.

- `YOCTOADT_TARGET_SYSROOT_IMAGE_<arch>`: The particular root filesystem used to extract and create the target sysroot. The value of this variable must have been specified with `YOCTOADT_ROOTFS_<arch>`. For example, if you downloaded both `minimal` and `sato-sdk` images by setting `YOCTOADT_ROOTFS_<arch>` to "minimal sato-sdk", then `YOCTOADT_ROOTFS_<arch>` must be set to either `minimal` or `sato-sdk`.

- `YOCTOADT_TARGET_SYSROOT_LOC_<arch>`: The location on the development host where the target sysroot is created.

After you have configured the `adt_installer.conf` file, run the installer using the following command:

         $ adt_installer

The ADT Installer requires the `libtool` package to complete. If you install the recommended packages as described in the Packages section of The Yocto Project Quick Start, then you will have libtool installed.

Once the installer begins to run, you are asked whether you want to run in interactive or silent mode. If you want to closely monitor the installation, choose “I” for interactive mode rather than “S” for silent mode. Follow the prompts from the script to complete the installation.

Once the installation completes, the ADT, which includes the cross-toolchain, is installed. You will notice environment setup files for the cross-toolchain in `/opt/poky/$SDKVERSION`, and image tarballs in the `adt-installer` directory according to your installer configurations, and the target sysroot located according to the `YOCTOADT_TARGET_SYSROOT_LOC_<arch>` variable also in your configuration file.

### Using a Cross-Toolchain Tarball

If you want to simply install the cross-toolchain by hand, you can do so by using an existing cross-toolchain tarball. If you install the cross-toolchain by hand, you will have to set up the target sysroot separately.

Follow these steps:

1. Go to and find the folder that matches your host development system (i.e. `i686` for 32-bit machines or `x86_64` for 64-bit machines).

2. Go into that folder and download the toolchain tarball whose name includes the appropriate target architecture. For example, if your host development system is an Intel-based 64-bit system and you are going to use your cross-toolchain for an ARM-based target, go into the `x86_64` folder and download the following tarball:

            yocto-eglibc-x86_64-arm-toolchain-gmae-1.1.tar.bz2

   As an alternative to steps one and two, you can build the toolchain tarball if you have a Yocto Project build tree. Use the `bitbake meta-toolchain` command after you have sourced the `oe-build-init script` located in the Yocto Project files. When the `bitbake` command completes, the toolchain tarball will be in `tmp/deploy/sdk` in the Yocto Project build tree.

3. Make sure you are in the root directory with root privileges and then expand the tarball. The tarball expands into `/opt/poky/$SDKVERSION`. Once the tarball in unpacked, the cross-toolchain is installed. You will notice environment setup files for the cross-toolchain in the directory.

After installing the toolchain, you must locate the target sysroot tarball and unpack it into a location of your choice.

### Using BitBake and the Yocto Project Build Tree

A final way of installing just the cross-toolchain is to use BitBake within an existing Yocto Project build tree. Follow these steps:

1. Source the environment setup script located in the Yocto Project files. The script has the string `init-build-env` as part of the name.

2. At this point, you should be sure that the `MACHINE` variable in the `local.conf` file found in the Yocto Project file structure's `conf` directory is set for the target architecture. Comments within the `local.conf` file list the values you can use for the `MACHINE` variable.

   You can populate the build tree with the cross-toolchains for more than a single architecture. You just need to edit the `MACHINE` variable in the `local.conf` file and re-run the BitBake command.

3. Run `bitbake meta-ide-support` to complete the cross-toolchain installation.

   If you change your working directory after you `source` the environment setup script and before you run the BitBake command, the command will not work. Be sure to run the `bitbake` command immediately after checking or editing the `local.conf` but without changing your working directory.

   Once BitBake finishes, the cross-toolchain is installed. You will notice environment setup files for the cross-toolchain in the Yocto Project build tree in the `tmp` directory. Setup script filenames contain the strings `environment-setup`.

After installing the toolchain, you must locate the target sysroot tarball and unpack it in a directory of your choice.

## Setting Up the Environment

Before you can use the cross-toolchain, you need to set up the toolchain environment by sourcing the environment setup script. If you used the ADT Installer or used an existing ADT tarball to install the ADT, then you can find this script in the `/opt/poky/$SDKVERSION` directory. If you used BitBake and the Yocto Project Build Tree to install the cross-toolchain, then you can find the environment setup scripts in in the Yocto Project build tree in the `tmp` directory.

Be sure to run the environment setup script that matches the architecture for which you are developing. Environment setup scripts begin with the string “`environment-setup`” and include as part of their name the architecture. For example, the environment setup script for a 64-bit IA-based architecture would be the following:

         /opt/poky/1.1/environment-setup-x86_64-poky-linux

## Kernels and Filesystem Images

You will need to have a kernel and filesystem image to boot using your hardware or the QEMU emulator. That means you either have to build them or know where to get them. You can find a quick example of how to build an image in the Building an Image section of The Yocto Project Quick Start.

The Yocto Project provides basic kernels and filesystem images for several architectures (`x86`, `x86-64`, `mips`, `powerpc`, and `arm`) that you can use unaltered in the QEMU emulator. These kernels and filesystem images reside in the Yocto Project release area - and are ideal for experimentation within Yocto Project.

If you plan on remotely deploying and debugging your application from within the Eclipse IDE, you must have an image that supports Sato. For information on the image types you can build using the Yocto Project, see Reference: Images in The Yocto Project Reference Manual.