SDK/Docs/1.1/Building a MeeGo chroot on Linux

Revision as of 11:46, 18 October 2010

This document describes how to create a MeeGo chroot environment from a stock image.

If you want a really quick method for developing on MeeGo where you don't need to build the chroot, use a MeeGo SDK download. The MeeGo SDK includes images tailored for QEMU and the needs of application development.

However, it can be useful to develop or test on a specific image, such as a recent weekly build. In this case, you may want to build your own chroot environment. However, additional disk space and manual steps may be needed to use these images; and features such as QEMU may not always be usable.

To help you decide what you need, here are the differences between stock MeeGo OS images and MeeGo SDK images:

If you think an SDK download would be best, see Hello World - MeeGo x86 development on Linux for details.

Otherwise, follow the steps below to build your own chroot environment.

Note that the approach covered here uses an x86 CPU to build software for an x86 version of MeeGo (e.g. a netbook image).

Pre-requisites

All that's required for this is a reasonably modern Linux distribution (e.g. Fedora 11, Ubuntu 9.10).

Download and unpack a MeeGo image

Get an image or tarball (with a UX) for either netbook or handset from one of these locations:

1. Release images
   • The release images (well tested) can be found here: http://meego.com/downloads/
2. Recently-built images
   • These images have been smoke tested, but may have issues. They can be found here: http://repo.meego.com/MeeGo/builds/trunk/.
   • Follow the links to the folder with the image type you want. The image file is either uncompressed (.img) or compressed (.sda.bin.bz2). Examples:
     • http://repo.meego.com/MeeGo/builds/trunk/1.0.90.3.20100921.1/netbook/images/meego-netbook-ia32/meego-netbook-ia32-1.0.90.3.20100921.1.img
       
     • http://repo.meego.com/MeeGo/builds/trunk/1.0.90.3.20100921.1/handset/images/meego-handset-ia32-aava-mtf-devel/meego-handset-ia32-aava-mtf-devel-1.0.90.3.20100921.1-sda.bin.bz2

Download tips

• Network: If your network connection is imperfect you should use a download tool that can continue if the connection is broken, such as wget:

$ wget --continue <link to image file>

• Checksum: Verify the checksum of the downloaded image. The correct checksum is included in the MANIFEST file in the same location as the image file. o generate the checksum from the downloaded file, run the following after downloading (on Linux, at least):

$ md5sum <image file>

The process for unpacking is slightly different, depending on the type of image.

Unpacking a netbook image

1. Install MeeGo Image Creator (MIC): use the instructions at http://wiki.meego.com/Image_Creation#Installation
2. Unpack the image using MIC:
   

   sudo mic-chroot --unpack-only -s /path/to/meego-chroot <image file>.usbimg

Replace /path/to/meego-chroot with your desired path.

Unpacking a handset image

1. Install kpartx (a tool for creating device maps from partition tables: because the handset images are raw disk images, this tool can be used to create a device map from the disk image, which can then be mounted on the filesystem)
   

   yum install kpartx

   or on non-RPM distros:

   apt-get install kpartx

2. Unpack the tarball:
   

   tar jxvf meego-0.90-preview-shcdk-20100512-001.tar.bz2

   This leaves you with a directory which contains the raw disk image you're interested in.

3. Create a device map from the raw image:
   

   cd meego-0.90-preview-shcdk-20100512-001
   sudo kpartx -a -v ./meego-0.90-preview-shcdk-20100512-001-sda.bin
   

   Note that this maps the first partition (p1) of the disk image onto the loop device /dev/loop0.

4. Mount the device map and copy the filesystem into the chroot location:
   

   mkdir ~/tmp-mnt   # temporary mount point
   sudo mount /dev/mapper/loop0p1 ~/tmp-mnt -o loop,ro
   mkdir ~/meego-chroot
   sudo rsync -av ~/tmp-mnt ~/meego-chroot
   sudo umount ~/tmp-mnt
   

5. Remove the device map:
   

   sudo kpartx -d -v ./meego-0.90-preview-shcdk-20100512-001-sda.bin
   

6. Remove the temporary mount point:
   

   rmdir ~/tmp-mnt
   

Using the chroot

Chroot into the image using mic-chroot.

To use the script with the unpacked chroot:

sudo mic-chroot /path/to/meego-chroot