Belkin Home Base; fun_plug, 'optware' and more

Post by **Mijzelf** » Fri Jun 15, 2012 9:31 pm

The flash chip of the Homebase has several megabytes free, and the box lacks a lot of features, so I decided to add some features.
New features:

dropbear-2012.55 (lightweight ssh server)
e2fsprogs-1.42.3
fdisk-1.3.0a
libmad & madplay
mdadm-3.2.5 & raid kernel modules (You always wanted raid5 on the box, didn't you?)
nfs-utils-1.1.6 & portmap-6.0
strace-4.7
bumped busybox to 1.20.1 & added a lot of modules
added support for fun_plug.sh scripts
added a lot of kernel modules, among which ext2, ext3, nfs, nfsd, cifs, usb-sound, ...
added the possibility to load the rootfs from an usb-disk/stick or an nfs server.
The root password is the same as the web interface password.

Install
You can find the firmware here, install it using the web interface.

fun_plug.sh
When an automounted partition contains a script fun_plug.sh, it will be executed. Two arguments are passed, the device and the mountpoint. Only FAT or NTFS formatted partition are automounted. So if you want an ext2/3 formatted disk to be mounted, add a (small) fat partition, with the fun_plug.sh script:

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#!/bin/sh

PARTITIONDEVICE=$1
MOUNTPOINT=$2
ROOTDEVICE=` echo ${PARTITIONDEVICE} | sed 's/[0-9]*//g' `

modprobe ext3

mkdir -p /mnt/mymountpoint
mount -o relatime ${ROOTDEVICE}2 /mnt/mymountpoint

(Assuming the ext3 partition is the 2nd one)
When you need both ext3 and ext2, make sure you first load the ext3 module, and then ext2. Else an ext3 partition will be mounted ext2, unless you explicitly specify ext3.

The script fun_plug.sh is called by /usr/sbin/fun_plugd.sh, which is called by /usr/sbin/sxsambaconf, which is called each time an usb disk is inserted/pulled.
/usr/sbin/fun_plugd.sh checks for the existence of an executable /root/fun_plugd.sh, and if it exists, it passes execution to that script. So if you want your own functionality on inserting usb disks, you can hook the script this way.

nfsd
To share directories using nfs, create a suitable /etc/exports file, and call '/etc/rc.d/rc.nfsd start'

nfs
You can mount external nfs shares:

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modprobe nfs
mkdir -p /mnt/mymountpoint
mount server:/share /mnt/mymountpoint -o nolock,vers=2

If you need locks, you should first start portmap.

cifs,smbfs
You can mount external samba shares:

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modprobe cifs
mkdir -p /mnt/mymountpoint
mount //server/share /mnt/mymountpoint -o user=username,pass=password

When cifs doesn't work, you could try smbfs. Load the module, and specify '-t smbfs'.

booting from usb, nfs (wired only)
You can add a line 'boot=usb' or 'boot=nfs,clientip,gateway,server:/share' to /etc/sysconfig/system.conf. Now press any 'Save' button in the webinterface, and the setting will be stored.
But first create a bootable filesystem. Mount the share or usb-disk (ext2/3), and copy the flash contents:

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cp -a /.rootfs/* /mnt/mymountpoint
mkdir -p /mnt/mymountpoint/.rootfs

Now create an executable script /mnt/mymountpoint/boot/boot.sh:

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#!/bin/sh

# move the /proc mount
/bin/mount --move /proc /.rootfs/proc

# pivot
cd /.rootfs
pivot_root . .rootfs
		                				
# Pass execution to new rootfs
exec /bin/busybox init

When booting from nfs edit /mnt/mymountpoint/etc/rc.d/rc.M, and remove the lines rc.nic and rc.network (You don't want to fiddle with the network, when your rootfs is nfs)

On boot /sbin/init (a script) will mount the filesystem on /.rootfs, and if an executable /boot/boot.sh exists, execution will be passed to that script.

usb sound

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modprobe snd-usb-audio
modprobe snd-pcm-oss
modprobe snd-mixer-oss

madplay music.mp3

'optware'
Unfortunately I wasn't able to find a suitable optware feed. There are enough feeds for mipsel (little endian), but not for mips.
But I found this. This exact instructions didn't work, for some reason LD_LIBRARY_PATH doesn't work.
But I found a work-around. I created a script joindirectories.sh, which makes it possible to 'add' the openwrt libraries to /usr/lib and /lib.

An example, installing midnight commander:
Mount an ext2/3 or nfs filesystem on /opt (which is a symlink to /tmpfs/opt):

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mkdir -p /tmpfs/opt
mount whatever /opt

Now install the base system:

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cd /opt
wget http://downloads.openwrt.org/backfire/10.03.1-rc6/ar71xx/packages/opkg_576-2_ar71xx.ipk
tar xzf opkg_576-2_ar71xx.ipk 
tar xzf data.tar.gz 
rm control.tar.gz data.tar.gz opkg_576-2_ar71xx.ipk 
wget http://downloads.openwrt.org/backfire/10.03.1-rc6/ar71xx/packages/libc_0.9.30.1-43.29_ar71xx.ipk
tar xzf libc_0.9.30.1-43.29_ar71xx.ipk
tar xzf data.tar.gz 
rm control.tar.gz data.tar.gz libc_0.9.30.1-43.29_ar71xx.ipk 
wget http://downloads.openwrt.org/backfire/10.03.1-rc6/ar71xx/packages/libgcc_4.3.3+cs-43.29_ar71xx.ipk
tar xzf libgcc_4.3.3\+cs-43.29_ar71xx.ipk 
tar xzf data.tar.gz 
rm control.tar.gz data.tar.gz libgcc_4.3.3\+cs-43.29_ar71xx.ipk 
joindirectories.sh /opt/lib /lib

Create a configuration file /etc/opkg.conf:

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src/gz snapshots http://downloads.openwrt.org/backfire/10.03.1-rc6/ar71xx/packages/ 
dest root /opt 
dest ram /tmp 
lists_dir ext /tmp/var/opkg-lists

Now you can run

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/opt/bin/opkg update
/opt/bin/opkg install mc

This added maybe some new libs to /opt/lib, so lets join again:

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joindirectories.sh /opt/lib /lib

Further some necessary files are installed in /opt/usr/lib and ../share. Let's join:

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joindirectories.sh /opt/usr/lib /usr/lib
joindirectories.sh /opt/usr/share /usr/share

Now run /opt/usr/bin/mc, and enjoy.

On next boot you'll have to rejoin, and re-create the /etc/opkg.conf file. But of course you can use a fun_plug.sh script for that. (You'll need it anyway to mount the /opt filesystem). You might want to edit /etc/profile to add /opt/bin, /opt/sbin, /opt/usr/bin and /opt/usr/sbin to the PATH.
Joining directories will take some memory. Not much, a tmpfs is mounted on the target directory, containing symlinks to the original files in squashfs, and symlinks to the /opt files are added.
This trick will work until you've got conflicting libraries, or the tmpfs takes too much memory. (You could add swap, of course)

Disabling features
You can disable telnetd, dropbear and/or fun_plug, if desired. Add the line 'disable=telnetd,fun_plug' to /etc/sysconfig/system.conf. Now press any 'Save' button in the webinterface, and the setting will be stored. On reboot telnetd and fun_plug will be disabled.
telnetd and dropbear are disabled by removing their line from /etc/inetd.conf. fun_plug is disabled by creating an empty script /root/fun_plugd.sh.
If you disable all, you will have to factory reset to get it back.