What does mountlo do? --------------------- This program essentially does the same as "mount -o loop". If you don't know what "mount -o loop" does, see the manpage of mount. Why then is mountlo needed? --------------------------- Because, for example "mount -o loop" can only run with super-user (root) privileges, while "mountlo" can be used by an ordinary user. Is this just a "suid" wrapper for mount then? --------------------------------------------- No, mountlo is not a "suid root" program. There's a small catch however: mountlo uses FUSE which needs to be installed as root. So does it just use FUSE to get around the root restriction? ------------------------------------------------------------ No. It uses FUSE to export the filesystem hierarchy and data, but the actual filesystem runs in userspace (in User Mode Linux actually). It sounds like a complicated way to solve a trivial problem ----------------------------------------------------------- Yes. However, there are advantages to doing things this way. If "mount -o loop" was just allowed to users, they possibly could craft a filesystem image which could crash the entire operating system. Filesystems were not written with arbitrary "input" in mind, so it is very hard to guarantee that all filesystems check for incorrect data. With the userspace approach, the worst that can happen is that the "mountlo" program crashes. The safety of the system is thus ensured. How to use mountlo? ------------------- Mounting: mountlo imagefile mountpoint Unmounting: fusermount -u mountpoint Does it accept any mount options? --------------------------------- Yes, most options of mount may be given to mountlo. What other packages are needed to run mountlo? ---------------------------------------------- You need FUSE version 2.2 or greater. What's the licence of mountlo? ------------------------------ The little code that makes up the glue between UML and FUSE is licenced under the GPL. UML is GPL. The FUSE kernel module is GPL, and the FUSE library is LGPL. Where is the latest version? ---------------------------- Look in http://sourceforge.net/projects/fuse Is it possible to rebuild mountlo from source? ---------------------------------------------- Yes. In fact it should be pretty easy, though it may take a couple of minutes. Dependencies: - Kernel version 2.6.29 source - Fuse version 2.8.0-pre2 source - Util-linux-ng 2.15-rc2 source The compile steps are: - Unpack the mountlo source. - Unpack the kernel source _under_ the mountlo source directory - Do the same with the fuse and util-linux-ng source packages - type "./configure" then "make" Who is responsible for this mess? --------------------------------- If you have any problems, patches or ideas you can turn to me <miklos@szeredi.hu> or the FUSE mailing list <fuse-devel@lists.sourceforge.net>.