How to build a web kiosk with Raspberry Pi and make the SD read-only.
16 Feb 2016 
Matteo Mattei 
kiosk raspberry 
Download latest Raspbian Lite distribution (Jessie in my case) from the official Raspberry website.
Then unzip the file and flash the image in the SD card:
sudo dd if=2016-02-09-raspbian-jessie-lite.img of=/dev/mmcblk0 bs=1M
Power up the RPi2 (or RPi1) with the SD plugged in and log in:
user: pi password: raspberry
Now configure the network (wired static ip in my case) editing /etc/dhcpcd.conf and adding the following lines at the bottom:
# my custom static settings
interface eth0
static ip_address=192.168.1.130/24
static routers=192.168.1.254
static domain_name_servers=192.168.1.254
Configure Kiosk
Execute raspi-config to cutomize some settings:
sudo raspi-config
In particular,
- Set localization (keyboard and system locale)
- Enable SSH
- Expand root partition
- Set autologin on console (B2)
At the end reboot your raspberry pi so that the new filesystem size will take effect.
Login again, update the system and install all needed software:
sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install midori matchbox-window-manager xserver-xorg x11-xserver-utils unclutter xinit
Now add tty group to pi user because pi needs to handle /dev/ttyX devices and adjust permissions accordingly at every system startup:
gpasswd -a pi tty
sed -i '/^exit 0/c\chmod g+rw /dev/tty?\nexit 0' /etc/rc.local
Now create a startup script:
vi /home/pi/startkiosk.sh
#!/bin/bash
# disable DPMS (Energy Star) features.
xset -dpms
# disable screen saver
xset s off
# don't blank the video device
xset s noblank
# disable mouse pointer
unclutter &
# run window manager
matchbox-window-manager -use_cursor no -use_titlebar no &
# run browser
midori -e Fullscreen -a http://www.google.com
and make it executable:
chmod +x /home/pi/startkiosk.sh
Then add the following lines at the end of /home/pi/.bashrc:
if [ -z "${SSH_TTY}" ]; then
xinit ~/startkiosk.sh
fi
This three lines allow starting X only when we login as pi directly but not from SSH.
Make the SD read-only
Backup your current /etc/fstab and create a new one with the following content:
proc /proc proc defaults 0 0
/dev/mmcblk0p1 /boot vfat ro 0 2
/dev/mmcblk0p2 / ext4 ro 0 1
tmpfs /tmp tmpfs defaults,noatime,mode=1777 0 0
tmpfs /var/log tmpfs defaults,noatime,mode=0755 0 0
tmpfs /var/lib/systemd tmpfs defaults,noatime,mode=0755 0 0
tmpfs /run tmpfs defaults,noatime,mode=0755 0 0
Then create a little script to help you to change the read-write/read-only mode of the filesystem everytime you need:
vi /home/pi/mountfs.sh
#!/bin/bash
case "${1}" in
rw)
sudo mount -o remount,rw /
echo "Filesystem mounted in READ-WRITE mode"
;;
ro)
sudo mount -o remount,ro /
echo "Filesystem mounted in READ-ONLY mode"
;;
*)
if [ -n "$(mount | grep mmcblk0p2 | grep -o 'rw')" ]
then
echo "Filesystem is mounted in READ-WRITE mode"
else
echo "Filesystem is mounted in READ-ONLY mode"
fi
echo "Usage ${0} [rw|ro]"
;;
esac
That’s it, reboot your RPi and enjoy your safe web kiosk!