The horrible, O(n) way is to just to loop over 0 .. n, see if it doesn't exist, if it doesn't then create and use it.
It's slow, it's racy (ie, don't run the script without locking :-) but it's a traditional UNIX way of doing things. PTYs were once allocated that way, fe. :-) Adrian On Sun, Oct 10, 2010, Zenaan Harkness wrote: > If I want to dynamically create loop devices, how would I dynamically > create loop device minor numbers in some way, from a shell script, > eg.: > > # setup: > UNIQUE_NAME=unique_login_name > LOOP_DEV=/dev/loop/$UNIQUE_NAME > MINOR_NUMBER=some_hash_or_what_??? > mknod $LOOP_DEV b 7 $MINOR_NUMBER > chown root.disk $LOOP_DEV > losetup $LOOP_DEV /home/$UNIQUE_NAME/source > mount $LOOP_DEV /home/$UNIQUE_NAME/target > ... > # tear down: > umount /home/$UNIQUE_NAME/target > losetup -d $LOOP_DEV > rm $LOOP_DEV > > Each dyn created loop device will have unique lifetime. So they will > be losetup -d'ed at different times, so eventually, the minor numbers > will need to be reused. > Is there any easy way to do this, whilst creating loop devices with > names which I assign, as in the example above? > > (I began a thread on this a few days ago (and no replies yet), which I > will update if you just post here on slug, at > http://forum.kernelnewbies.org/read.php?12,2126 > ) > > TIA > Zen > -- > SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ > Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $24/pm+GST entry-level VPSes w/ capped bandwidth charges available in WA - -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
