Redirect file system access depending on the UID. This allows several users to access the "same" absolute path without interfering with each other. Every user gets their own individual view on the path.
Do audit the code before you use it in any security-critical application. The code in its current form has not been audited in any form, and likely contains bugs that are exploitable by a malicious user!
Suppose you have two users userA and userB. Both users shall be able to access the directory /my-directory, but they shall have two independent views on the directory.
First, you have to create the physical locations that both users will be accessing:
mkdir /unshared
theUID=`id -u userA`
mkdir /unshared/$theUID
chown userA /unshared/$theUID
theUID=`id -u userB`
mkdir /unshared/$theUID
chown userB /unshared/$theUID
or, if you prefer for loops in bash:
rootdir=/unshared
for user in userA userB
do
if theuid=`id -u "$user"`
then
mkdir "$rootdir/$theuid"
chown "$user" "$rootdir/$theuid"
fi
done
After this, you can mount the unshared file system:
unsharedfs -o allow_other /unshared /my-directory
Note that the unshared file system needs to be mounted by the root user in order to be effective (even when user_allow_other has been set in fuse.conf). Otherwise, the FUSE file system does not know the UID of the user that is accessing the mountpoint, and all access will be redirected to the UID-directory of the user that mounted the file system.
- make
- make install PREFIX=/some/prefix
If you want to update the manpage, you need the help2man utiltiy. The manpage is created (semi-)automatically from the usage information of the unsharedfs binary and additional text in the file doc/unsharedfs.h2m. If you make any changes in either one, update the manpage by running:
make update-man