Re: [PATCH 4/5] mountmgr.sys: Add the ability to query filesystem attributes on a file handle.

[Erich E. Hoover]

On Wed, Mar 24, 2021 at 10:59 AM Alexandre Julliard  wrote:
> "Zebediah Figura (she/her)"  writes:
> > On 3/18/21 11:54 AM, Erich E. Hoover wrote:
> > > @@ -2019,6 +2057,30 @@ NTSTATUS query_volume( void *buff, SIZE_T insize, SIZE_T outsize, IO_STATUS_BLOC
> > >      }
> > >      LeaveCriticalSection( &device_section );
> > > - if (!volume && input->info_class ==
> > >
> > > FileFsAttributeInformation)
> > > - {
> > > -
> > >    enum fs_type fs_type = FS_UNKNOWN;
> > > -
> > >    HANDLE hProcess, handle;
> > > -
> > >    BOOL ret;
> > > -
> > >    int fd;
> > > -
> > > -
> > >    if (!(hProcess = OpenProcess( PROCESS_DUP_HANDLE, FALSE, input->process )))
> > > -
> > >        return status;
> >
> > This is right, but it looks wrong. I'd recommend returning early in
> > the if (volume) block, and explicitly returning STATUS_NO_SUCH_DEVICE
> > instead of initializing it at the top.
>
> Actually I don't think mountmgr has any business resolving client
> handles itself. There has to be a better way.

There are a couple other ways that I can see:
1) duplicate the handle on the calling end
2) call fstatfs() on the calling end and send the appropriate
"fallback" fs_type for the mountmgr to decode

Do either of these sound good to you?

Best,
Erich