bug in cygwin tar reading unexpected input(s)...

[Russell VT]

Replay by from my phone, so it's a bit brief...

Try opening a Cygwin terminal AS administrator, making sure it gives you
the "process may modify the system" warning dialog, etc... Then repeat

If it works, or complains less, then the problem is permissions at *some*
level.

Despite Windows having "administrator" type groups, they are STILL
protected parts of the filesystem, etc. There will be fewer protections by
using the "system" account, etc.

WARNING: Using this account MAY produce irreparable harm to the system. Do
this at your own risk.

-- 
Russell M. Van Tassell
russellvt@gmail.com

This message was sent from my wireless handheld device.

On Tue, Jun 15, 2021, 14:14 L A Walsh <cygwin@tlinx.org> wrote:

>
>
> On 2021/06/15 00:16, Russell VT wrote:
> > I think we need more context, here... as what does Windows versus Cygwin
> > think those permissions are...???
> ---
>         Which permissions?  The error is 'no such object', not
> 'access denied'.  I believe it is similar to trying to read (or
> modify) xattr's or acl's on linux symlinks.
>
> >
> > Are you running your terminal, as you... or did you run it as
> Administrator?
> ---
>         I am in group Administrators as well as Domain Admins
> (Samba Domain).  Domain Admins and System are both in the
> local Administrators group.
>
>
> > Have you run an update, and not rebooted?
> ---
>         I don't believe so at that time, but I have rebooted since then.
> The problem only occurred on files that were symlinks as seen by Windows
> and Cygwin.
> >
> > There should be some "basic shell debugging" done here, first...
> ---
>         I'm not sure what you mean.  Oops, I forgot to list the
> command line, but thought that "--xattrs" might be implied from the
> fact that the error was about retrieving xattrs.
>
>         Cmdline was using shell script calling a function, "backup_dir"
> with "ProgramData" from the root directory, where the function was:
>
> backup_dir() {
>   my DIR=${1:?}
>   tar c --acls --xattrs --sparse -b 2048 --one-file-system "$DIR" |
>     dd bs=1M iflag=fullblock of="/b/June_backups/$DIR" oflag=nonblock
> }
>
>
> > since
> > there's a disconnect from when tar gets its file list, and when it
> > physically goes to retrieve a (possibly temporary) file. It will also
> > complain about directories it can read, but not access.
> ---
>         Those were symlinks, not directories.
> > So, it would be
> > better to figure out what the "difference" is between what you expect,
> > and what actually happened with the tar.
> ---
>         I would expect it might not complain about not being
> able to read xattr's on symlinks?  I don't think it complains about
> not being able to read them on linux -- or at least I've never seen
> such.
>
> > Unfortunately, permission issues between Windows and Cygwin can be
> > */extremely/* complex (ie. there are a ton of details missing here,
> > which might make it easier to help troubleshoot).
> ---
>         What necessary details are missing?
>
> >
> > Hope that helps point you in a good direction.
> ---
>         Not sure. I thought I was reporting a bug in cygwin tar
> giving an error about trying to read xattrs on symlinks, as I don't
> believe it gives an error on linux doing the same thing.  Does it?
> Thanks for your questions, but I'm still not very clear on what
> I left out.
>
>         I'd tend to ignore the error on what appeared to be
> a misspelled filename, as I'm not even sure how to recreate
> that file, but attempting to dump xattrs on a symlink seems like
> a pretty straight forward symptom/testcase.  What more details
> do you think would be pertinent?
>
> Thanks!
> -Linda
>
>
> >
> > Cheers!
> > Russell VT
> >
> > On Mon, Jun 14, 2021 at 9:22 PM L A Walsh <cygwin@tlinx.org
> > <mailto:cygwin@tlinx.org>> wrote:
> >
> >     Tar'ing up a windows dir (ProgData) had some unexected failures:
> >
> >     Several of the sort:
> >
> >     tar: Dbgview: Warning: Cannot llistxattrat: No such file or directory
> >     tar: Desktops: Warning: Cannot llistxattrat: No such file or
> directory
> >     tar: DiskView: Warning: Cannot llistxattrat: No such file or
> directory
> >     tar: LoadOrd: Warning: Cannot llistxattrat: No such file or directory
> >     tar: portmon: Warning: Cannot llistxattrat: No such file or directory
> >
> >     Where the item listed (Dbgview, DiskView, etc) is a
> >     windows symlink like:
> >
> >     2019/02/07  22:53    <SYMLINK>      Dbgview [SI\Dbgview.exe]
> >     2019/02/07  22:53    <SYMLINK>      Desktops [SI\Desktops.exe]
> >     2019/02/07  22:53    <SYMLINK>      DiskView [SI\DiskView.exe]
> >
> >     and stems from the use of the --xattrs switch.
> >
> >     Win7SP1x64
> >     cygcheck (cygwin) 3.2.0
> >
> >     The tar continued and finished much as it would after an unreadable
> >     file.
> >
> >     Another error, maybe similar,
> >
> >
> >     tar: C\:Prog64FastPictureViewer: Warning: Cannot file_has_acl_at: No
> >     such file or directory
> >
> >      From a file in "C:\Program Files\FastPictureViewer" [likely
> mis-]named
> >     "C:Prog64FastPictureViewer"
> >
> >     It seems to be a .dll, that somehow got its name mangled.
> >
> >     Not sure what it was trying to do, but the file seems to be 'in-use'.
> >
> >
> > --
> > Russell M. Van Tassell <russellvt@gmail.com <mailto:russellvt@gmail.com
> >>
>