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s5804
Asked: 2010-07-12 02:04:45 +0800 CST

What permissions are needed to write a PID file in /var/run?

  • 772

On Ubuntu:

touch: cannot touch `/var/run/test.pid': Permission denied

I am starting start-stop-daemon and like to write the PID file in /var/run start-stop-daemon is run as my-program-user

/var/run setting is drwxr-xr-x  9 root  root

I like to avoid putting my-program-user in the root group.

ubuntu permissions root pid

6 Answers

  1. Best Answer

    By default, you can only write to /var/run as a user with an effective user ID of 0 (ie as root). This is for good reasons, so whatever you do, don't go and change the permissions of /var/run... Instead, as root, create a directory under /var/run:

    # mkdir /var/run/mydaemon

    Then change its ownership to the user/group under which you wish to run your process:

    # chown myuser:myuser /var/run/mydaemon

    Now specify to use /var/run/mydaemon rather than /var/run.

    You can always test this by running a test as the user in question.

    • 88 
  2. mkdir /var/run/mydaemon
chown myuser:myuser /var/run/mydaemon

    this will not work, since it will be lost at the next reboot (/var/run is a tmpfs on Ubuntu).

    The only feasible solution is to run mkdir and chmod as part of the startup scripts.

    • 18

  3. You can try this. Create a directory /var/run/test/ and then change the permission of this directory to the same user as your program runs. " chown /var/run/test/" . Now in your application change the location of the PID file to /var/run/test/test.pid. This should get things working for you.

    • 3

  4. What about using the "sticky" bit on /var/run ?

    chmod +t /var/run ?

    Probably mess up some other apps, but it seems like it would be another solution.

    I'll stick with creating a separate /var/run folder for now, however.

    • 3

  5. Entries in the /etc/permissions are permanent. Make an entry there to make the ownership and permissions for a directory permanent.

    • 2

  6. To avoid putting your program-user in the root group, allow others write access:

    # chmod 757
    • -7