Raspberry Pi 3 - Browser Client

This is a guide for setting up a RAM based RPI3 which is able to run X, and firefox. This tutorial will go through setting up auto login for Alpine, and starting X on boot without user interaction. It is a type of kiosk machine.

Tested as of 05/2020

Overview

This guide uses the following:

• aarch64 img
• RPI3
• community repo is used.

It is based off of this guide: Raspberry_Pi. Due to the dependencies required to run X and FF, there is very little RAM disk space for the user to operate in, after this tutorial is complete (about 30MB is v3.11). Take this into consideration. It's possible that the RPI4 with its additional RAM, may fare better.

aarch64 is used, because firefox-esr is in the community repo. armhf (as of v3.11) does not have firefox prepackaged in the base or community repo.

See https://pkgs.alpinelinux.org/packages?name=*firefox*&branch=v3.11&arch=aarch64

Note that the aarch64 build is not compatible with all RPI. See Raspberry Pi.

Steps

Base Install

These steps are duplicated from Raspberry_Pi page.

Use fdisk or gdisk to format the SD card. You must have the first partition be a bootable, FAT filesystem. e.g.:

Command (m for help): p
Disk /dev/sdb: 59.5 GiB, 63864569856 bytes, 124735488 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Device     Boot Start      End  Sectors Size Id Type
/dev/sdb1  *     2048 62916607 62914560  30G  b W95 FAT32

mkdosfs -F 32 /dev/sdX1

untar onto mounted disk

mount /dev/sdX1 /mnt/folder
tar xvf archive.tar -C /mnt/folder/.

If you plan to enable increased RAM (e.g. for RPI4 with 2 or 4GB) or other config settings, do so in a usercfg.txt now.

Again, duplicating the Raspberry Pi page

   Insert the SD card into the Raspberry Pi and turn it on
   Login into the Alpine system as root. Leave the password empty.
   Type setup-alpine
   Once the installation is complete, commit the changes by typing lbu commit -d

saving space: busybox instead of chronyd, dropbear instead of openssh

After setup, make sure dropbear is installed

apk add dropbear

Start it:

rc-service dropbear start

Add it to the default runlevel:

rc-update add dropbear

If you need an accurate clock, enable software/ntp here (optional, i don't need a clock for the website I view).

rc-update add swclock boot # enable the software clock 
rc-update del hwclock boot # disable the hardware clock
setup-ntp

Browser Client Install

Enable community repo (/etc/apk/repositories) (uncomment community)

apk update

install firefox and X dependencies:

apk add libx11-dev libxft-dev libxinerama-dev adwaita-gtk2-theme adwaita-icon-theme ttf-dejavu

Note that the fonts/icon theme are required for FF to display correctly. Without these, firefox will load, but text will not render on the browser menus.

the RAM tmp fs remaining can be viewed while installing, with watch df -h

install firefox

apk add firefox-esr

install X

setup xorg-base

The RPI also requires for X:

apk add xf86-video-fbdev

At this point, we have about 421MB used up (if NTP was not setup).

Filesystem                Size      Used Available Use% Mounted on
devtmpfs                 10.0M         0     10.0M   0% /dev
shm                     457.9M         0    457.9M   0% /dev/shm
/dev/mmcblk0p1           30.0G    259.4M     29.7G   1% /media/mmcblk0p1
tmpfs                   457.9M    420.0M     37.9M  92% /
tmpfs                    91.6M    188.0K     91.4M   0% /run
/dev/loop0               24.9M     24.9M         0 100% /.modloop

lbu_commit -d

AutoLogin, Startx automatically on Boot

At this point, you should be able to login as root, and run startx manually. Now, we will add a number of configuration files that allow this to happen without user interaction.

/root/ doesn't save any files, so it's necessary to edit files in /etc/ and lbu_commit -d after all changes. First let's add a file that will call firefox. lbu_commit is alpine local backup. If you want to save folders other than /etc see:https://wiki.alpinelinux.org/wiki/Alpine_local_backup#Include_special_files.2Ffolders_to_the_apkovl also see: /etc/apk/protected_paths.d/lbu.list

create a file named /etc/startup.sh:

#!/bin/ash
firefox http://somewebsite.com

We have to edit xinitrc, and the profile configs. Normally, this would be done in the user's directory, but here we will use the globals for simplicity.

mv /etc/X11/xinit/xinitrc /etc/X11/xinit/xinitrc_BAK
nano /etc/X11/xinit/xinitrc

In this file put:

/etc/startup.sh

At the end of /etc/profile (leave the existing file) append

startx

And remember to: lbu_commit -d For autologin, alpine uses busybox, which has an alias to /sbin/getty as well as /bin/login. It's possible to navigate to /sbin/ or /bin/ and run /sbin/getty -h to see what settings are available. To have root auto login upon boot, review the existing inittab and edit as needed, according to the config below.

# Set up a couple of getty's
#tty1::respawn:/sbin/getty 38400 tty1
tty2::respawn:/sbin/getty 38400 tty2
tty3::respawn:/sbin/getty 38400 tty3
tty4::respawn:/sbin/getty 38400 tty4
tty5::respawn:/sbin/getty 38400 tty5
tty6::respawn:/sbin/getty 38400 tty6

tty1::respawn:/bin/login -f root

Disable Screensaver, and refresh webpage (optional)

As a kiosk, the RPI will need to have the screensaver (DPMS) disabled. Also, my particular application (video streams) required a refresh occasionally. These were managed with xorg.conf, xdotool, and crontab respectively.

Contents of /etc/X11/xorg.conf

Section "Extensions" Option "DPMS" "Disable" EndSection

# apk add xdotool

# crontab -u root -e 
* * * * * DISPLAY=:0 /usr/bin/xdotool key F5

Note that xset is not an option here, as it's not included by default. It can be installed from repositories, if needed. That's it. Now reboot, and watch the RPI boot into firefox without user intervention. At this point, you have a functioning minimal OS booting from RAM, with firefox, and ~30MB of available space for further configuration.

Tips/Troubleshooting

Why was this setup used? Why not Awesome, or dwm?

It should be noted that the author ran through a few different setups of alpine on the rpi, and found that (dwm | awesome) & firefox required too many dependencies to run on an RPI3 with 512MB in /tmp (running in RAM), or other browsers which used less dependencies were unstable (the application was viewing video streams). Therefore, running firefox direct off X was just barely able to fit into the available space, and was stable. This is one of the reasons aarch64 was used, instead of armhf.

If your application doesn't require media (i.e. a static webpage) you may be able to run other browsers, such as midori, falkon, or surf, without stability issues on the RPI.

It is possible that VLC would also fit into the limited space on the RPI. This was not tested.

Width & height of firefox doesn't fit the monitor

Firefox can be called with -height and -width flags, e.g.

firefox -width 480 -height 640 somewebsite.com

Periodic Firefox Crashes due to Low Memory

With the RPI3, I found firefox crashing reliably after a couple days uptime of watching video. On the server I saw notices of memory running out. Somewhere there was a memory leak, and with the small amount of RAM available, it would crash firefox, leaving the screen blank.

The solution was to setup a nightly reboot of the system via cron, and this has kept the system stable since. However, if I was to do this again, I would try an RPI4 with >1GB ram and this may obviate the need for a nightly reboot.

Related Links

• dwm
• Raspberry Pi