Re: nobody/nogroup - ITP maildir-bulletin
>> For the Debian version should I use group/users such as postnogr and
>> postnous? Or should I just use nobody/nogroup?
>
>I don't think nobody is a good idea. If you break into one program run
>as nobody, you break into them all... (not sure how/if this applies to
>setuid root code).
I agree. However we don't want to have too many system users and groups...
>Some with the group, especially as you seem to use it to
>control access...
Yes.
>However, your description above leaves me slightly confused as
>to what this program does. Here is my impression:
>
>1. Your program is called from postfix as user:group postnous:postnogr.
>2. It is setuid root, but only can be run from the postnogr group.
>3. It manually delivers the message to Maildir.
Right.
>Why is this better then allowing postfix to deliver the message?
It creates a single copy of the message and creates a link to it from each
home directory. This means that if you have 30000 users on a system and want
to send them each a 10K message (such as the legalistic stuff many
universities send all their students nowadays) it will only take 10K of
storage and a (relatively) small amount of time to deliver. If you deliver it
any other way it will take 300M of storage and a significant amount of
delivery time.
In the system I am mainly writing this for (AIX machine) I expect to deliver
a bulletin to 30000 accounts in between 10 and 15 minutes and the machine
will be on 100% CPU time for that period (IBM's JFS really sucks for this
type of thing - read comp.sys.aix in DejaNews to see the discussion I started
on Filesystem Performance). If the same mail was delivered using procmail
then I would expect it to take much more than twice as long. Maybe an hour
of CPU time.
Even for systems with less users and better OSs and hardware (such as one of
my clients running a K6-3 at 350MHz for 1000 users) delivering email to
everyone can be painfully slow.
Also with my bulletin system it's easy to unsend bulletins and to edit
bulletins. For example if you send a bulletin to 30000 users telling them
"the system will be down on Friday" then on Friday evening you can change it
to "the system was down on Friday" for the users who haven't yet read it.
Utrecht University has been using similar software for years. I am now
re-writing it for them and have got permission to GPL it so that you can be
unpaid beta-testers (how else am I going to get paid to do Debian development
;).
--
I'm in Utrecht. I'd like to meet any Linux users in the area, or any other
part of the Netherlands.
Reply to: