How to auto run program on beaglebone black

taek8461 · March 5, 2020, 10:13am

Hi
I am using a Beaglebone Black with new debian
I used it with reference to the following link
https://www.digikey.com/eewiki/display/linuxonarm/BeagleBone+Black#BeagleBoneBlack-RootFileSystem

I want a program to run automatically after the Beaglebone black power is turned on

I changed the file ( /lib/systemd/system/serial-getty@.service) for auto log in as following

...
[Service]
ExecStart=-/sbin/agetty -a debian -s %I 115200
...

Automatic login works good.
but I have a shell script and a program.
modem.sh

#!/bin/bash

echo "GPIO pin setting ------------------------"
config-pin P9.24 uart
config-pin P9.26 uart
config-pin P9.11 uart
config-pin P9.13 uart
sleep 5

echo "set modem call -------------------------"
sudo echo -ne 'at$qcrmcall=1,1\r' > /dev/ttyUSB2
sleep 2

echo "set wwan setting -----------------------"
sudo dhclient -v wwan0

./LoraControl

.bashrc

...
if ! shopt -oq posix; then
    if [ -f /usr/share/bash-completion/bash_completion ]; then
        . /usr/share/bash-completion/bash_completion
    elif [ -f /etc/bash_completion ]; then
        . /etc/bash_completion
    fi
fi

sudo ./modem.sh

After the Beaglebone is automatically logged in, when the modem.sh is executed, it stops with a message asking for the superuser’s password.

I want to run the shell script (modem.sh) without message asking password
so I want to run the program ( LoraControl ) automatically without any input after the board is powerd on

Please let me know how to do it.

and one more questing
Is there another way to make modem.sh run automatically without putting it in .bashrc?

Thank you

RobertCNelson · March 5, 2020, 3:21pm

@taek8461 couple things, first let’s solve the “sudo” issue. If you want to call something with sudo without a password prompt, you can add the specific applications in “/etc/sudoers”… Now, you need to be very careful editing this file, as you can very easily lock yourself out of the file system…

/etc/sudoers

debian ALL=NOPASSWD: /sbin/dhclient, /bin/echo

Next, i’d nuke your whole “sudo ./modem.sh”, with a systemd service file. Drew has an awesome “config-pin” example systemd service that you could use…

github.com

adafruit/adafruit-beaglebone-io-python/blob/master/test/notes/run_config-pin_during_startup.md

## Create file `/usr/bin/enable-i2c-pins.sh`
 **sudo vi /usr/bin/enable-i2c-pins.sh**
```
#!/bin/bash

config-pin p9.17 i2c
config-pin p9.18 i2c
```
**sudo chmod 755 /usr/bin/enable-i2c-pins.sh**

## Create file `/lib/systemd/system/enable-i2c-pins.service`
**sudo vi /lib/systemd/system/enable-i2c-pins.service**
```
[Unit]
Description=Enable I2C pins
After=generic-board-startup.service

[Service]
Type=simple
ExecStart=/usr/bin/enable-i2c-pins.sh

This file has been truncated. show original

Plus, as it’s already run as root, you won’t need any sudo calls if you use Drew’s example. (it’ll also wait till the system can call config-pin)…

Regards,

taek8461 · March 6, 2020, 6:42am

hi RobertCNelson

I edited the file “/etc/sudoers” as follow

but when I powered on the board, the message is displayed as follows.

it have permission denied and ask password.
I don’t know why.

I changed “sudo ./modem.sh” in .bashrc to “./modem.sh”

How can i resolve it.
thank you

RobertCNelson · March 6, 2020, 3:11pm

@taek8461, remove “, /dev/ttyUSB2” from /etc/sudoers, that is a “device” not an “application”…

In your script, you have a race condition with /dev/ttyUSB2, it’s best to make sure that device exists before you write to it… (this is easier with a systemd service file) But to hack up your current script more, change:

echo "set modem call -------------------------"
sudo echo -ne 'at$qcrmcall=1,1\r' > /dev/ttyUSB2
sleep 2

to:

echo "set modem call -------------------------"
until [ -d /sys/class/tty/ttyUSB2/ ] ; do
	sleep 1
	echo "Debug: waiting for ttyUSB2"
done

echo "Debug: ttyUSB2 is active"
sudo echo -ne 'at$qcrmcall=1,1\r' > /dev/ttyUSB2
sleep 2

Also in “.bashrc”, use the actual path for “./modem.sh” your just asking for trouble… If it’s under /home/debian/ just add it… “./modem.sh” -> “/home/debian/modem.sh” or where ever you actually placed “./modem.sh”…

Edit, looking at your log, the other sudo password came during:

echo "set wwan setting -----------------------"
sudo dhclient -v wwan0

So, dhclient is using a different path… run: “sudo which dhclient” then update /etc/sudoers with where it’s located on your root file system.

voodoo@hades:~$ sudo which dhclient
/sbin/dhclient

Regards,

taek8461 · March 9, 2020, 1:59am

Hi RoberCNelson
Thank you for your response
I am getting a lot of help from you.
I tried running it according to your solution
but I still have problems.

/dev/ttyUSB2 has been a permission denied.
dhclient request password.
the path is /sbin/dhclient

I don’t know what’s wrong.

Below is /etc/sudoers

Below is modem.sh

Please, let me know the solution.
Thank you.

RobertCNelson · March 9, 2020, 2:05pm

@taek8461, that’s odd, okay, let’s just change it to allowing everything:

debian  ALL=NOPASSWD: ALL

Regards,

taek8461 · March 11, 2020, 2:33am

Hi
Thank you for your response

When I tried to run an app (including sudo) on prompt, it didnot ask the password.
but when powered on and run automatically, it asked the password
How can I resolve it?

Regards.

RobertCNelson · March 11, 2020, 4:48am

@taek8461, okay not sure what’s causing that. So enough with the random hacks, and let’s do things the right way for a systemd based system in 2020.

First what’s the actual location of “./LoraControl”, you should change that in below:

First we will create the enable-modem file: sudo nano /usr/bin/enable-modem.sh

It’s contents:

#!/bin/bash

echo "GPIO pin setting ------------------------"
config-pin P9.24 uart
config-pin P9.26 uart
config-pin P9.11 uart
config-pin P9.13 uart
sleep 5

echo "set modem call -------------------------"
until [ -d /sys/class/tty/ttyUSB2/ ] ; do
	sleep 1
	echo "Debug: waiting for ttyUSB2"
done

echo "Debug: ttyUSB2 is active ---------------"
echo -ne 'at$qcrmcall=1,1\r' > /dev/ttyUSB2
sleep 2

echo "set wwan setting -----------------------"
/sbin/dhclient -v wwan0

echo "Running LoraControl --------------------"
#TODO: replace "./" with actual location...
./LoraControl

Set enable-modem.sh permissions:
sudo chmod 755 /usr/bin/enable-modem.sh

Next Create the service file: sudo nano /lib/systemd/system/enable-modem.service

It’s contents:

[Unit]
Description=Enable Modem
After=multi-user.target

[Service]
Type=forking
ExecStart=/usr/bin/enable-modem.sh

[Install]
WantedBy=multi-user.target

Now reload systemd and enable the new service file:

sudo systemctl daemon-reload
sudo systemctl enable enable-modem.service

On bootup you should be able to grep it’s startup with journalctl | grep Modem

Regards,

taek8461 · March 11, 2020, 8:01am

Hi.
I resolved it.
Thank you so much.