Re: [Fwd: [bug #6047] rm -f "" prints diagnostic message under the Hurd]

[Ognyan Kulev]

Marcus Brinkmann wrote:
> "" is not a valid filename.  However, POSIX also specifies that
> "unlink" should return ENOENT if path is the empty string.  So maybe
> that is the real bug, that the Hurd returns EINVAL and not ENOENT in
> this case?  Can you look closer into that?

libdiskfs/lookup.c:diskfs_lookup has the following code (where NAME is 
what we are looking for):

...
if (name[0] == '\0')
  {
    if (ds)
      diskfs_null_dirstat (ds);
    return EINVAL;
  }
else
...

In glibc, the basic routines for turning file names into ports are 
hurd/hurdlookup.c:__hurd_file_name_lookup and friends (which end up 
calling __hurd_file_name_lookup).  There is a LOOKUP argument (pointer 
to function), but I couldn't find where it is used by callers.  By 
default, __dir_lookup is assumed (in hurd/lookup-retry.c).  And 
libdiskfs/dir-lookup.c:dir_lookup RPC relies on diskfs_lookup for the 
components of the file name.

I've heard that "" file name has some special use in the Hurd.  So there 
is possibility that changing EINVAL to ENOENT will have unexpected 
sequences.  Perhaps Roland or Thomas would enlighten us if such change 
will break something.

Regards,
ogi