[Solved] Bash: killing child processes

some-guy94 · 2010-01-04 18:38:43

I decided to make a session manager that will kill all child processes before exiting, the only problem is that it doesn't kill them all.
I tried using the same function, and using it in conjunction with

yes >/dev/null & bash
yes >/dev/null & bash
yes >/dev/null & bash
yes >/dev/null & bash

running in a terminal, and it sent all of them the TERM signal.

I'm out of ideas.
Code is here.

The relevant section is:

# Kill child process of given parent
# This uses PIDs not names
# Also prints out a list of child pids that should be killed
# FIXME: Clean this up a bit
kill_child_processes()
{
    PARENT_ID=$1
 
# Find child processes and put them in the form PID%seperator%COMMAND
    local CHILD_PROCESSES=$(ps o ppid,pid,command |                             \
                awk "{if (\$1 == $PARENT_ID) {print \$2,\"_\",\$3;}}" |             \
                sed 's| _ |%seperator%|')
# Do this for each child
    for child in $CHILD_PROCESSES; do
 
    # Extract the PID and COMMAND into separate variable from $child
    local child_pid=$(echo $child | sed 's|%seperator%.*||')
    local child_command=$(echo $child | sed 's|.*%seperator%||')
 
    # If the child command has child processes, recurse through it
    if [ "$(ps o ppid,pid,command | awk "{if (\$1 == $child_pid) {print \$2;}}")" != "" ]; then
        kill_child_processes $child_pid
    fi
 
    # If the command isn't part of a blacklist, send it the TERM signal
    if [ x$(for dont_kill_command in $DONT_TERM; do \
            [ x$dont_kill_command == x$child_command ] && echo "MATCH"; \
        done) == x"" ]; then
        kill $child_pid & 
        # echo the PID so we can use it later
        echo $child_pid
    fi
    done
}

Thanks.

Last edited by some-guy94 (2010-01-13 22:48:39)

gradgrind · 2010-01-05 09:48:13

You might like to try pkill / pgrep with the -g option?

some-guy94 · 2010-01-05 23:08:42

gradgrind wrote:

You might like to try pkill / pgrep with the -g option?

Unfortunately that isn't what I'm looking for, I want this to work with multiple sessions(not that difficult), and also work with other apps on other tty's.

Currently what it does is it runs ps o ppid,pid,command x which gives a nice table

1234 5678 command1
1234 5679 command2
...

and if the ppid matches the session's pid, it's pid is saved, and (this part is looped) if it has child processes, then the function is run on the pid, afterward the pid is killed.

It works when I separate the function from the rest of the script, but when it is in a session it fails to work properly.

Last edited by some-guy94 (2010-01-05 23:11:57)

some-guy94 · 2010-01-13 22:49:31

I solved this by changing all the 'ps [args]' to 'ps [args] x'.

I can't believe I forgot that.

Thanks for all the help.

Arch Linux

#1 2010-01-04 18:38:43

[Solved] Bash: killing child processes

#2 2010-01-05 09:48:13

Re: [Solved] Bash: killing child processes

#3 2010-01-05 23:08:42

Re: [Solved] Bash: killing child processes

#4 2010-01-13 22:49:31

Re: [Solved] Bash: killing child processes

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