Create directory in /var/run/ at startup

Question

I'm using apache2 and postgres running on Ubuntu Server 10.04.
I have removed the startup scripts for both of these apps and I'm using supervisor to monitor and control them. The problem I have run into is that both of these need directories in /var/run (with the correct permissions for the users they run under) for pid files. How do I create these during startup as they need to be created as root and then chown'd to the correct user?

Edit
It seems the best way to so this is to creat the directories with custom init scripts. As I have no shell scripting skills at all how do I go about this?

Answer 1

According to Debian policy,

/var/run and /var/lock may be mounted as temporary filesystems, so the init.d scripts must handle this correctly. This will typically amount to creating any required subdirectories dynamically when the init.d script is run, rather than including them in the package and relying on dpkg to create them.

Obviously, Ubuntu inherits from Debian, and as far as I know this policy is unchanged there.

The best solution is to modify your new startup scripts such that when the services are launched, if these directories do not exist, they will be created.

Answer 2

This kind of thing should be put in "/etc/rc.local". Example:

#!/bin/sh -e
# 
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

if [ ! -d /var/run/foo ]; then
  mkdir /var/run/foo/
  chown user1:group1 /var/run/foo/
fi
if [ ! -d /var/run/bar ]; then
  mkdir /var/run/bar/
  chown user2:group2 /var/run/bar/
fi
exit 0

Answer 3

In reply to this comment:

There are currently no startup scripts for the servcies. The supervisor daemon is started by the init.d scripts and then the other services are started by this service, which should not run as root.

If your supervisor is started from init.d script, then just create another init.d script with the preferences to be run before the supervisor starts ( how you achieve this is totally dependent on your flavor of **IX ).

In its start method create needed directories with required permissions.

In its stop method tear those directories down.

Answer 4

In the end I used this code in the init.d script for the supervisor process:

while IFS=: read file user group
    do
        if [ -d $file ]; then
            chmod 2775 $file
        else
            install -d -m 2775 -o $user -g $group $file
        fi
    done < "/etc/run_dirs.txt"

Which reads a file containing rows with the following format and creates the appropriate dirs and permissions:

path/to/dir:user:group

Answer 5

I see a few options:

1. Create the directories at install time
2. Create a file of all directories to be created at startup, then write a program that create all of those files and run it at startup (from a startup script that has root privs).

Other options that are riffs on this could also be made to work.