rmdir(2) and mkdir(2) both return EISDIR for argument "/"

[Gary Jennejohn]

On Fri, 06 Nov 2009 22:09:49 +0100 (CET)
Alexander Best <alexbestms at math.uni-muenster.de> wrote:

> here's a completely new patch. all the changes are in kern/vfs_syscall.c. so
> kern/vfs_lookup.c now stays just the way it is (please revert any changes from
> the previous patches i posted).
> 
> after applying the patch this is the output from a slightly modified version
> of the test app i attached in my very first post:
> 
> rmdir errno: 16 (EBUSY) <- EBUSY is required by POSIX
> mkdir errno: 17 (EEXIST)
> rename errno: 22 (EINVAL)
> 
> these are the results when called with "/" as arg. the output doesn't differ
> if run with or without superuser privileges.
> 
> when run with "." as arg this is the output as regular user:
> 
> rmdir errno: 22 (EINVAL)
> mkdir errno: 17 (EEXIST)
> rename errno: 13 (EACCES)
> 
> and as superuser:
> 
> rmdir errno: 22 (EINVAL)
> mkdir errno: 17 (EEXIST)
> rename errno: 22 (EINVAL)
> 
> does this look reasonable? would be nice if mkdir and rmdir would also check
> privileges at first like rename, but that's a different story i guess. ;)
> 

The only problem I see with this is that vfs_syscall.c now has knowledge
about the internal details of vfs_lookup.c

Maybe just mention in the comments that this is the case and could be
a problem if vfs_lookup.c is changed for some reason?  That's what I
do when I have to use something like this.

But we don't want to turn this into a gigantic bikeshed - we already
have enough of those.

---
Gary Jennejohn