How To Create and Use RFS Customization Script

Table of contents
HOWTO Create and Use an RFS Customization Script with Factory

Summary

This HOWTO covers the process for creating an RFS customization script to modify the Factory generated target RFS.

NOTE: This HOWTO assumes that the Desktop Factory has been configured and built prior to the use of the RFS customization script. If these Factory configuration and build steps have not been completed yet, please do so before continuing with this HOWTO.

Making systematic modifications to the Factory-generated RFS during the BSP/SDK build process with the use of an RFS customization script can be broken up into two distinct tasks, each of which is covered within this HOWTO:

Create RFS Customization Script
1. Write RFS Customization Script
2. Verify RFS Customization Script
Integrate RFS Customization Script with Factory

RFS Customization Script Introduction

There are instances where certain modifications need to be made to the Factory-generated RFS beyond simply adding or overwriting files within the RFS (as can be accomplished with the use of an RFS Overlay Archive). Some examples are:

dynamically adding, moving, or removing files
modifying file contents
modifying file permissions
any conditional operations

The RFS customization script is run immediately prior to the RFS images creation during the BSP/SDK build.

Create RFS Customization Script

Write RFS Customization Script

One of the most important aspects of using the RFS customization script facility within Factory is the script itself. The script can be created anywhere on the development host with your favorite text editor, but for purposes of this HOWTO, it will be created within the user-created src/local/ directory within Factory's top-level.

vim src/local/myRFSscript.sh

From here, the contents of the RFS customization script are left largely to the requirements of the tasks at hand. The RFS customization script is run from the top-level Factory directory and is passed the RFS working directory (build_[arch]-timesys-linux-[libc]/rfs/) as the only parameter. The example RFS customization script here is commented to explain what each section does and is intended for reference purposes. Note Copy and pasting this code from your web browser may not maintain proper formatting.

#!/bin/bash

# change directory to the RFS working directory or
# stop execution if unable to do so
RFSDIR=$1
cd $RFSDIR || exit 1

# backup etc/network/interfaces file
if [ -f etc/network/interfaces] ; then
  mv etc/network/interfaces etc/network/interfaces.bck
fi

# create new interfaces file and
# setup eth0 dhcp configuration
cat >> etc/network/interfaces  <<EOF
auto eth0
iface eth0 inet dhcp
EOF

# prevent openssh from automatically starting
# by removing initscript
if [ -f etc/init.d/S50-openssh ] ; then
  rm etc/init.d/S50-openssh
  rm etc/init.d/K50-openssh
fi

# add tty0 console
cat >> etc/inittab <<EOF
ds:2345:respawn:/sbin/mingetty --noclear tty0
EOF

# mount hdb on /work
mkdir work
cat >> etc/fstab <<EOF
/dev/hdb /work ext2 defaults 0 0
EOF

# create /etc/init.d/rc.local to start our apps
mkdir -p etc/init.d
cat > etc/init.d/rc.local <<EOF
#!/bin/sh
# put app init stuff here
case "\$1" in
  start)
    echo "starting custom app" 
  ;;
  stop)
    echo "stopping custom app" 
  ;;
esac
EOF

Once the script is created, it will also need to be marked as executable before proceeding.

chmod +x src/local/myRFSscript.sh

Verify RFS Customization Script

You can verify the RFS Customization script acts as expected by simply executing it from the within the top-level Factory directory and inspecting the results in the RFS working directory (build_[arch]-timesys-linux-[libc]/rfs/). Once the results of the script are satisfactory, integration with the BSP/SDK build process is the next step.

Integrate RFS Customization Script with Factory

Copy RFS Customization Script to an Accessible Location

If the RFS customization script has been not been created from the steps listed above, ensure it is copied to a location accessible to the Desktop Factory (where elevated privileges are not needed).

cp /PATH/TO/myRFSscript.sh /PATH/TO/factory/src/local/

Enable RFS Customization Script in Workorder

The RFS Customization Script is enabled by listing the script file with a fully qualified path in the Factory workorder. This can be done via the menuconfig interface.

Run make menuconfig from the top-level Factory directory
Navigate to Target Configuration > Build RFS > RFS Customization script
Enter script file and location - in our example, file://$(TSWO_SRC_LOCAL_LOCATION)/myRFSscript.sh
Exit menuconfig and save workorder

Note the $(TSWO_SRC_LOCAL_LOCATION) into the workorder in step 3 above evaluates to src/local in the top-level Factory directory.

Clean and Rebuild RFS and Installer

In order to rebuild the RFS images, the rfs build state in Factory needs to be reset. This is accomplished with the rfs-distclean make target, run from the top level Factory directory.

make rfs-distclean

With the RFS reset and ready to be rebuilt, the following can be run from the top-level Factory directory to regenerate the RFS images and SDK Installer:

make rfs && installers

or simply running "make" will automatically rebuild both the RFS images and the SDK installer to reflect the modifications to the RFS based on the newly applied RFS customization script.