6.8 KiB
Install Persistent Hook
When the device reboots, any changes in ramfs are lost, but the device is using flash with squashfs and jffs2 file systems. I have not discovered how to modfiy and upload an image to squashfs, but with jffs2 there is a way to install a hook. That hook even survives an upgrade that is done afterwards (see end of this section)!
To start, you have to enable telnet and that may require a downgrade in the first step. See Downgrade Firmware and Enable telnetd.
Below is an output of mount command and cat /proc/mtd output:
# mount
rootfs on / type rootfs (rw)
/dev/root on / type squashfs (ro,relatime)
proc on /proc type proc (rw,relatime)
none on /var type ramfs (rw,relatime)
none on /etc type ramfs (rw,relatime)
none on /tmp type ramfs (rw,relatime)
none on /media type ramfs (rw,relatime)
none on /sys type sysfs (rw,relatime)
none on /dev/pts type devpts (rw,relatime,mode=600)
mdev on /dev type ramfs (rw,relatime)
devpts on /dev/pts type devpts (rw,relatime,mode=600)
mdev on /dev type ramfs (rw,relatime)
devpts on /dev/pts type devpts (rw,relatime,mode=600)
/dev/mtdblock8 on /mnt type jffs2 (rw,relatime)
/dev/mtdblock9 on /vendor type jffs2 (rw,relatime)
# cat /proc/mtd
dev: size erasesize name
mtd0: 01000000 00010000 "ALL"
mtd1: 00030000 00010000 "Bootloader"
mtd2: 00010000 00010000 "Config"
mtd3: 00010000 00010000 "Factory"
mtd4: 00200000 00010000 "bkKernel"
mtd5: 001df508 00010000 "Kernel"
mtd6: 00950af8 00010000 "RootFS"
mtd7: 00b30000 00010000 "Kernel_RootFS"
mtd8: 00080000 00010000 "user"
mtd9: 00200000 00010000 "user2"
#
The mtd8 device named "user" is not erased at a reboot, because it may contain a preset list (file totalqueue.xml and/or keymap.xml) in /mnt directory. There's also a third file in the directory called radio.xml.
The mtd9 device named "user2" is not erased at a reboot, because it may contain additional 'vendor' data. It is mounted as /vendor and a hook can be installed in /vendor/user directory as described below. On the Up2Stream Pro device that I own that directory was already present and a script called user.sh was located in that directory.
After a reset to factory settings with release v4.6.415145, release date 2022/04/27, the device has a web interface. To run this web interface the device calls a shell script ***/vendor/user/user.sh where some code can be added to:
/usr/sbin/telnetd
cd /system/workdir/
. ./evn.sh
chmod 777 /vendor/user/daemonize
chmod 777 /vendor/user/ws_server
/vendor/user/daemonize /vendor/user/ws_server
Note: The telnetd is NOT installed, because the file is missing in the (read only) directory /usr/bin.
Just append the code below at the end of that file. On the device where the script was not present, I've just created it.
sleep 5
# get telnetd from full version of busybox and start in background
mkdir /tmp/bin
wget -O /tmp/bin/busybox -T 5 http://10.1.1.22/linkplay/a31/bin/busybox -q
chmod 555 /tmp/bin/busybox
ln -s /tmp/bin/busybox /tmp/bin/telnetd
ln -s /tmp/bin/busybox /tmp/bin/ash
/tmp/bin/telnetd telnetd -l/tmp/bin/ash &
echo '#!/bin/sh' >/tmp/bin/help
echo '/tmp/bin/busybox --help' >>/tmp/bin/help
chmod 755 /tmp/bin/help
# shut down WiFi after 5 min, but only if the device is connected by LAN (eth2) and got an IP addr on that interface
sleep 300
lanIPup=`ifconfig eth2 | grep 'inet addr:' | wc -l`
if [ $lanIPup -eq 1 ]; then
ifconfig ra0 down
ifconfig apcli0 down
ifconfig apcli0 down
fi
unset lanIPup
# Uncomment to disable sleep after 15 minutes (I haven't used this code - just an example from Crymeiriver)
#while true; do sleep 60; echo 'AXX+MUT+000' >/dev/ttyS0; done &
The shutdown of the 'apcli0' WiFi interface does not work within the script when called in the first place, however it works a bit later if executed manually. So I added the 300 seconds (5 minutes) sleep and executed the command twice. Now it looks that it works as expected. I also added some code, so that the WiFi interface is NOT shut down if the Ethernet / LAN interface (eth2) does not get an IP address.
Compared to the the section Enable telnetd, the code above has a little enhancement included, because the downloaded version of busybox is used as the shell /tmp/bin/ash instead of "build-in" version. You can see the difference, because the shell prompt message is BusyBox v1.23.2 (2016-09-27 07:54:34 CEST) built-in shell (ash) instead of BusyBox v1.12.1 () built-in shell (ash).
A list of all commands that are included is shown with /tmp/bin/busybox --help or just 'help' (see shell script below). You may create symbolic links for the commands you need (recommended, see below for an example) or start them directly, e.g. /tmp/bin/busybox dmesg.
So far, the device fetches the full version of busybook after each reboot, but stores that binary in ramfs. With df command you can verify the free space on each of the file systems.
IMPORTANT: The hook is NOT called, if the device got stuck during an upgrade, e.g. if you have a products.xml file with a product ID that is matching your product that triggers an upgrade, but got stuck for some reasons. Therefore I recommend to rename the products.xml file on your server to something else and block or redirect any upgrade requests on the Internet. See Downgrade Firmware section at the end for details.
Note: Neither the directory /vendor/user nor the user.sh script were installed on my Up2Stream devices when I bought them with version 4.2. That may have changed with v4.6
Here's an older script that I found on the device (used to start a daemon called socket):
# cat user.sh
#!/bin/sh
echo "runing custom's app socket.............."
sleep 5
chmod 777 /vendor/user/socket
sn=`ps -ef | grep /vendor/user/socket | grep -v grep |wc -l`
echo $sn
if [ $sn -eq 0 ]; then
/vendor/user/socket &
fi
For testing purpose, you may reboot and telnet to the device afterwards.
IMPORTANT: The good thing is, that this hook even suvives an upgrade that is done afterwards (tested with v4.6.415145, release date 2022/04/27.):
Mac-mini ~ % curl -s 'http://10.1.1.52/httpapi.asp?command=getStatusEx' | jq
{
"uuid": "FF31F09EAC1C213319CC79B5",
"DeviceName": "Wohnzimmer",
"GroupName": "Wohnzimmer",
"ssid": "Wohnzimmer_4029",
"language": "en_us",
"firmware": "4.6.415145",
"hardware": "A31",
"build": "release",
"project": "UP2STREAM_PRO_V3",
"priv_prj": "UP2STREAM_PRO_V3",
"project_build_name": "a31rakoit",
"Release": "20220427",
"temp_uuid": "B4D39CBCE2C2015F",
...
}
Mac-mini ~ % telnet 10.1.1.52
Trying 10.1.1.52...
Connected to 10.1.1.52.
Escape character is '^]'.
BusyBox v1.23.2 (2016-09-27 07:54:34 CEST) built-in shell (ash)
/system/workdir # exit
Connection closed by foreign host.