[SOLVED] Make a autorun USB that executes a shell script on the USB drive?

414N · 08-13-2012, 02:51 AM

I guess there should be no issues with inotify on ARM. See man inotify for additional info.
If you prefer a shell based solution, I guess we need additional information, like:

is the USB device always mounted in the same locations?
the script to execute has always the same name?
is there a way to look if the script needs to be run?

riahc3 · 08-13-2012, 07:01 AM

Quote:

Originally Posted by 414N

I guess there should be no issues with inotify on ARM. See man inotify for additional info.
If you prefer a shell based solution, I guess we need additional information, like:

is the USB device always mounted in the same locations?

Yes. It will always be /tmp/media/sda1 or if it gets confudes because it still thinks it is mounted, /tmp/media/sda2. Either way I can check all I want problably

Quote:

Originally Posted by 414N

the script to execute has always the same name?

Yes. It will always have the same name

Quote:

Originally Posted by 414N

is there a way to look if the script needs to be run?

If it is on the USB and I plug it in, it has to run. As a matter of fact, once I plug it in, it runs and it can demount if you wish. This way, I unplug it and then replug it, it mounts again and it runs again if neccesary.

414N · 08-13-2012, 08:29 AM

Quote:

Originally Posted by riahc3

Yes. It will always be /tmp/media/sda1 or if it gets confudes because it still thinks it is mounted, /tmp/media/sda2. Either way I can check all I want problably

Good. I think that with a proper grep on /etc/mtab this matter can be solved in 0 seconds

Quote:

Originally Posted by riahc3

Yes. It will always have the same name

Good, another simplification going

Quote:

Originally Posted by riahc3

If it is on the USB and I plug it in, it has to run. As a matter of fact, once I plug it in, it runs and it can demount if you wish. This way, I unplug it and then replug it, it mounts again and it runs again if neccesary.

Okay, but I wanted to know another thing (I probably chose the worst words to ask it). With this autorun script you're going to overwrite some IP settings inside a config file for OpenVPN, if I'm not mistaken. Shouldn't you make sure, prior to running the script, that it really needs to overwrite those settings? Think of a user continuously plugging in and out the USB drive with the script (not the smartest of users, I presume

): every time the drive is plugged in the script is run and the relevant config line is overwritten over and over.
To sum it all up: are you really sure it is desirable for clients to run the script everytime the drive is inserted without checking if it's needed (assuming this can be checked) or without being prompted about the change that's gonna happen (something like "old IP: xx.xx.xx.xx ->new IP: yy.yy.yy.yy. Apply? [Y/n]")?

riahc3 · 08-14-2012, 02:03 AM

Quote:

Originally Posted by 414N

Okay, but I wanted to know another thing (I probably chose the worst words to ask it). With this autorun script you're going to overwrite some IP settings inside a config file for OpenVPN, if I'm not mistaken. Shouldn't you make sure, prior to running the script, that it really needs to overwrite those settings? Think of a user continuously plugging in and out the USB drive with the script (not the smartest of users, I presume

): every time the drive is plugged in the script is run and the relevant config line is overwritten over and over.
To sum it all up: are you really sure it is desirable for clients to run the script everytime the drive is inserted without checking if it's needed (assuming this can be checked) or without being prompted about the change that's gonna happen (something like "old IP: xx.xx.xx.xx ->new IP: yy.yy.yy.yy. Apply? [Y/n]")?

I thought about this and Ive come up with several solutions:

1: Selfdelete the script from the USB once it has ran
2: Unmount the USB once the script has ran
3: Both

I cant prompt the user as there is no GUI. Im inclinded to do 1 as this would avoid the user running it over and over and over again (like you mentioned). He would either have to redownload it from his email or I would have to resend it to him.

deadeyes · 08-14-2012, 03:00 AM

I am not fond of what you are trying to accomplish. For me this would be a general security issue.

414N · 08-14-2012, 03:00 AM

Well, we could do something like this:

check if the new IP is already in place and, if so, do nothing;
log every action performed by the script in a relevant log file, i.e. /var/log/scriptName.log

This introduces a new problem, though: in the long run, the log file could become huge if, for example, the "smartest user ever" from my previous example has nothing to do apart from playing with a USB drive and the router.
This could be mitigated if you're already using logrotate for the other log files on the machine.

riahc3 · 08-14-2012, 03:45 AM

Quote:

Originally Posted by deadeyes

I am not fond of what you are trying to accomplish. For me this would be a general security issue.

Why? Noone knows what the script is named nor do they have access to the actual shell. Also, this is for a pastry company; If they have shell script programmers, they are doing it wrong....

Quote:

Originally Posted by 414N

Well, we could do something like this:

check if the new IP is already in place and, if so, do nothing;
log every action performed by the script in a relevant log file, i.e. /var/log/scriptName.log

This introduces a new problem, though: in the long run, the log file could become huge if, for example, the "smartest user ever" from my previous example has nothing to do apart from playing with a USB drive and the router.
This could be mitigated if you're already using logrotate for the other log files on the machine.

Logging? Why would I log? Im not too intrested in logging.

We could do that check also. I dont mind if it overwrites it but yes, checking is more efficient so I agree.

BTW, on record, I have NO idea on how to write these scripts so........I hope you can help me write this. Thank you very much

414N · 08-14-2012, 01:35 PM

Let's start writing down the cron-able script (this should work on ash):

Code:

#!/bin/sh

scriptName="XYZ.sh"
usbRoot=/tmp/media
scriptLoc="$(find "$usbRoot"/sd* -name "$scriptName" | head -n1 )"

if [ "$scriptLoc" ]
then
	sh "$scriptLoc"
fi

You can try it using a dumbed-down XYZ.sh script which prints a line to a file, like this:

Code:

#!/bin/sh

echo "$(date) - cron script launched successfully!" >> /tmp/testWrite.txt

Of course the USB drive needs to be mounted in /tmp/media/sdXn on the test machine, unless you change the usbRoot variable

riahc3 · 08-16-2012, 01:52 AM

Quote:

Originally Posted by 414N

Let's start writing down the cron-able script (this should work on ash):

Code:

#!/bin/sh

scriptName="XYZ.sh"
usbRoot=/tmp/media
scriptLoc="$(find "$usbRoot"/sd* -name "$scriptName" | head -n1 )"

if [ "$scriptLoc" ]
then
	sh "$scriptLoc"
fi

You can try it using a dumbed-down XYZ.sh script which prints a line to a file, like this:

Code:

#!/bin/sh

echo "$(date) - cron script launched successfully!" >> /tmp/testWrite.txt

Of course the USB drive needs to be mounted in /tmp/media/sdXn on the test machine, unless you change the usbRoot variable

Looks great!

Im going to try this right now. Will tell you results now...

riahc3 · 08-16-2012, 03:09 AM

Didnt work

Here is a screenshot, showing what I believe is all the neccesary information to diagnostic this:

http://img52.imageshack.us/img52/6609/crontab.png

And yes, I waited over a minute.

414N · 08-16-2012, 03:56 AM

Strange, I just re-tested it on my machine and it works ok.
Are you sure your cron daemon is running? How did you edit the crontab for root?

riahc3 · 08-16-2012, 03:58 AM

Restarted the device and now it works!

Thats step one: Making a script that works so thats great. Thank you

Now, the next thing is implement what I actually want to do.

---------- Post added 08-16-12 at 08:59 AM ----------

Quote:

Originally Posted by 414N

Strange, I just re-tested it on my machine and it works ok.
Are you sure your cron daemon is running? How did you edit the crontab for root?

After restarting the device, it now works

riahc3 · 08-16-2012, 05:00 AM

If you need me to explain what exactly the second script needs to do, please ask

Thank you.

414N · 08-16-2012, 05:04 AM

Some additional details are indeed needed.
What file contains the OpenVPN settings you need to change?
Post an example reporting the exact line to be changed and how it should be changed.

riahc3 · 08-17-2012, 02:24 AM

Quote:

Originally Posted by 414N

Some additional details are indeed needed.
What file contains the OpenVPN settings you need to change?
Post an example reporting the exact line to be changed and how it should be changed.

client
proto udp
remote 192.168.100.199 1194
cipher AES-128-CBC
user root
group root
verb 2
mute 20
keepalive 10 120
comp-lzo
persist-key
persist-tun
float
resolv-retry infinite
nobind
ca /etc/ssl/certs/openvpn-tunnel0-ca.crt
cert /etc/ssl/certs/openvpn-tunnel0.crt
key /etc/ssl/certs/openvpn-tunnel0.key
dh /etc/ssl/certs/dh1024.pem
dev tun
up "/etc/openvpn/tunnel0-up"
down "/etc/openvpn/tunnel0-down"

Thats the configuration file. Where it says:

remote 192.168.100.199 1194

is what I need to replace. I need to read off a usb that contains a file named (for example) update.txt that has:

remote 192.168.100.123 1194

and replace it.