Root PID's

Dale255 · 04-05-2012, 10:32 AM

Hi,

I'm trying to write a little script to kill certain PID's. Which I seem to have done, but I also want to make sure that no root processes are killed too.

How can I tell the diffrence between a user PID and a Root PID?

I know by using ps -ef I can see the user associated with the PID but I have no idea how to add this in to my script.

Here is what I have so far (don't laugh!

)

Code:

#!/bin/bash
# print the process list
ps -ef

# if the string is empty
if [ -z $(pidof gcalctool) ];

	then
		echo "This process is currently not running"
# if process is running kill and echo

else 
	kill -9 $(pidof gcalctool) ;

echo "The calculator was terminated" 


fi

suicidaleggroll · 04-05-2012, 10:36 AM

One option is to just run the script as a user. Users can't kill root's processes.

uhelp · 04-05-2012, 10:52 AM

you should never use "kill -9 something", as the process got no chance to end properly.
A very bad habbit.
First try HUP and the other signals. The very last resort is "kill -9 ...."

ps -u someuser
gives you all processes run under the according UID

Dale255 · 04-05-2012, 11:02 AM

Quote:

Originally Posted by uhelp

you should never use "kill -9 something", as the process got no chance to end properly.
A very bad habbit.
First try HUP and the other signals. The very last resort is "kill -9 ...."

ps -u someuser
gives you all processes run under the according UID

Thanks everyone

So how exactly would I incorporate the ps -u in to a script?

What I basically want to do is, if the UID is root, don't kill the process.

unSpawn · 04-05-2012, 11:08 AM

There should be system users to consider as well, so better make it:

Code:

PSUIDMIN=$(awk '/^UID_MIN/ {print $2}' /etc/login.defs)
/bin/ps --no-header ax -eo pid,uid,cmd | while read PSPID PSUID PSARGS; do
 [ $PSUID -ge ${PSUIDMIN:=500} ] && echo "$PSPID $PSARGS"
done

Dale255 · 04-05-2012, 11:20 AM

Quote:

Originally Posted by unSpawn

There should be system users to consider as well, so better make it:

Code:

PSUIDMIN=$(awk '/^UID_MIN/ {print $2}' /etc/login.defs)
/bin/ps --no-header ax -eo pid,uid,cmd | while read PSPID PSUID PSARGS; do
 [ $PSUID -ge ${PSUIDMIN:=500} ] && echo "$PSPID $PSARGS"
done

Thanks unspawn, I really can't make top from tail with that though. How could i put that in to my script?

unSpawn · 04-05-2012, 11:36 AM

Code:

#!/bin/bash --
# Disable after debugging:
set -vxe
# Get the minimal value for unprivileged user Ids:
PSUIDMIN=$(awk '/^UID_MIN/ {print $2}' /etc/login.defs)
# Print the process list and read in three variables:
/bin/ps --no-header ax -eo pid,uid,cmd | while read PSPID PSUID PSARGS; do
        # If user Id is ( not root and not system user ) echo and kill:
        if [ $PSUID -ge ${PSUIDMIN:=500} ]; then
                echo -en "Killing \"${PSARGS:0:24}\": "
                kill -15 $PSPID && sleep 10s
                kill -15 $PSPID && sleep 10s
                kill -9 $PSPID && echo "done." || echo "failed."
        fi
done
exit 0

Code:

function help() { echo "Bash scripting guides:
http://www.tldp.org/HOWTO/Bash-Prog-Intro-HOWTO.html 
http://www.tldp.org/LDP/Bash-Beginners-Guide/html/index.html 
http://www.gnu.org/software/bash/manual/html_node/index.html
http://www.grymoire.com/Unix/Sh.html
http://www.tldp.org/LDP/abs/html/ 
http://wooledge.org/mywiki/BashFAQ?action=show&redirect=BashFaq 
http://wooledge.org/mywiki/BashPitfalls"; }

Dale255 · 04-05-2012, 11:54 AM

Quote:

Originally Posted by unSpawn

Code:

#!/bin/bash --
# Disable after debugging:
set -vxe
# Get the minimal value for unprivileged user Ids:
PSUIDMIN=$(awk '/^UID_MIN/ {print $2}' /etc/login.defs)
# Print the process list and read in three variables:
/bin/ps --no-header ax -eo pid,uid,cmd | while read PSPID PSUID PSARGS; do
        # If user Id is ( not root and not system user ) echo and kill:
        if [ $PSUID -ge ${PSUIDMIN:=500} ]; then
                echo -en "Killing \"${PSARGS:0:24}\": "
                kill -15 $PSPID && sleep 10s
                kill -15 $PSPID && sleep 10s
                kill -9 $PSPID && echo "done." || echo "failed."
        fi
done
exit 0

Code:

function help() { echo "Bash scripting guides:
http://www.tldp.org/HOWTO/Bash-Prog-Intro-HOWTO.html 
http://www.tldp.org/LDP/Bash-Beginners-Guide/html/index.html 
http://www.gnu.org/software/bash/manual/html_node/index.html
http://www.grymoire.com/Unix/Sh.html
http://www.tldp.org/LDP/abs/html/ 
http://wooledge.org/mywiki/BashFAQ?action=show&redirect=BashFaq 
http://wooledge.org/mywiki/BashPitfalls"; }

Way over my head. I just want to be able to stop the process being killed if the UID is root.

unSpawn · 04-06-2012, 08:38 AM

Quote:

Originally Posted by Dale255

I just want to be able to stop the process being killed if the UID is root.

I thought you wanted to kill non-root processes?..

Quote:

Originally Posted by Dale255

Way over my head.

Try this:

Code:

#!/bin/bash --
# Remove uncomment the line below when you understand what the script does:
set -vxe
PSUIDMIN=$(awk '/^UID_MIN/ {print $2}' /etc/login.defs)
/bin/ps --no-header ax -eo pid,uid,cmd | while read PSPID PSUID PSARGS; do
 if  [ $PSUID -ge ${PSUIDMIN:=500} ]; then
  # Remove the echo and quotes if you really, really want to kill:
  echo "kill -15 $PSPID"
 fi
done
exit 0