[SOLVED] Attempting to add a custom script to run at boot (FC19)

kaza · 05-02-2014, 03:49 PM

Hello,

I'm attempting to add a custom script to run at boot time
(as root) by using the systemd services (as per explanation
at "http://docs.fedoraproject.org/en-US/Fedora/19/html/Installation_Guide/s1-boot-init-shutdown-run-boot.html").

I created the file

/lib/systemd/system/ka_setup_tty.service

with the contents:

Code:

[Unit]
Description=A service that executes a user script on startup (setting up /dev/ttyS0).
Wants=network.target


[Service]
ExecStart=/root/bin/setup_ttyS0_for_ka
Type=oneshot

[Install]
WantedBy=multi-user.target

Then I created the script /root/bin/setup_ttyS0_for_ka
with contents:

Code:

#!/bin/tcsh


chmod o+rw /dev/ttyS0

stty -F /dev/ttyS0 19200

(I'm building some hardware than uses RS-232 interface
and I want to save me the repeated action of changing the ttyS0
parameters as a root each time I turn the PC on and start
working, I would like the setup to be done during the boot time.)

I checked that running the "/root/bin/setup_ttyS0_for_ka"
as a root does what I need but when I reboot, I see that
nothing changed in the ttyS0 setup, therefore the script didn't
run (successfully). Did I made an error with

"Wants=network.target"

or

"WantedBy=multi-user.target"?

I just left these lines as in example.
What service sets up all the serial ports, maybe I need to
wait for its end?
Am I right assuming that when "systemd" parses the "*.service"
files and executes what's in them, it runs as "root"?

Does anyone sees something obvious I forgot?

TIA for any ideas,

unSpawn · 05-03-2014, 04:30 AM

Not the right answer (I remember adding services to Systemd but I kind of forgot what it took ;-p) would it be easier to just enable the "rc.local" service and add your commands to /etc/rc.d/rc.local? Or add / edit a udev rule with these commands to be run as soon as /dev/ttyS0 becomes available?

vl23 · 05-04-2014, 03:54 PM

use an udev rule to modify the device file ownership, as it is a tty the logind service is probably screwing with it also, and you might want to check out its config since it is responsible for things like VTs and ttys, I have no idea since my knowledge of that piece of garbage is limited.
Why not try Slack or Sabayon, they are sensible distros that do not have init systems which do stuff you do not want or need?

DJ Shaji · 05-04-2014, 07:46 PM

Generally speaking, rc.local is executed at the very end of the boot process. It should be the simplest way to run a command you would be running by hand every time you boot up the system.

kaza · 05-05-2014, 09:44 AM

Hi, thanks for they replyes!

I created the file

/etc/rc.d/rc.local

with the following contents:

Code:

#!/bin/tcsh

setup_ttyS0_for_ka

(the directory of that script is in the "path"),
changed its permissions to be executed by "root":

Code:

<root localhost.localdomain>.../root>ls /etc/rc.d/rc.local
-rwxr--r--. 1 root root 35 May  5 17:20 /etc/rc.d/rc.local

rebooted ... and nothing, still the permissions and baud rate of ttyS0
are default and not as they are after running the "setup_ttyS0_for_ka" script.

What else I forgot?

kaza · 05-05-2014, 09:57 AM

Solved!

After thinking that relying on "path" might be too early
in the boot process, I changed the reference to the script
to be a full path:

/root/bin/setup_ttyS0_for_ka

, rebooted - and now it works.

Thanks for the help!

Now I have to try remembering how to mark the thread as "solved"...