rmdir(2) behavior to prevent pax(1) from working

Matthew Dillon dillon at apollo.backplane.com
Mon Dec 27 12:03:09 PST 2004

: I notice that the current rmdir(2) implementation allows
: rmdir(2) to remove a directory path whose final component is
: either "." or ".." (such as /tmp/foo/bar/.).
: This sounds no problem, but the pax(1) utility depends on this
: behavior at least.  Try the following commands:
:  % cd /tmp
:  % mkdir a b
:  % touch a/foo
:  % cd a
:  % pax -r -w . ../b
: In this case pax(1) should go into a infinite loop.
: The SUSv3 also says "If the path argument refers to a path
: whose final component is either dot or dot-dot, rmdir() shall fail."
: so I think it is better to be fixed.
: Probably kern_rmdir() @ sys/kern/vfs_syscalls.c needs
: some sort of sanity check for the trailing "." and "..",
: but unfortunately I have no idea about a concrete solution because
: I am not familiar with the new VFS/namecache API...
: Could anyone investigate this problem?
:| Hiroki SATO

    Hmm.  I think this was an artifact introduced by the new VFS code.  It 
    should be easy to fix.  I'll have a go at it today.


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