Re: [PATCH] EmulatorPkg/WinHost: Add EFI_BUFFER_TOO_SMALL for return status.

["Guomin Jiang" <guomin.jiang@intel.com>]

Hi Ray,

I have review the UEFI spec and code, the logic is ok, it my mistake.

In my test, I pass the *BufferSize with 0, but it is unexpected input value.

Sorry for it.

> -----Original Message-----
> From: Ni, Ray
> Sent: Friday, March 20, 2020 3:12 PM
> To: Jiang, Guomin <guomin.jiang@intel.com>; devel@edk2.groups.io
> Cc: Justen, Jordan L <jordan.l.justen@intel.com>; Andrew Fish
> <afish@apple.com>
> Subject: RE: [PATCH] EmulatorPkg/WinHost: Add EFI_BUFFER_TOO_SMALL
> for return status.
> 
> Guomin,
> It's OK to do a partial read. There is no requirement for a single read that
> returns all the file content back to caller.
> 
> Some comments to your commit message:
> Besides, the commit message is too simple. It should indicate what was
> wrong in the code and what's your expected behavior.
> 
> The Bugzilla comments are very detailed actually.
> 
> Thanks,
> Ray
> 
> > -----Original Message-----
> > From: Jiang, Guomin <guomin.jiang@intel.com>
> > Sent: Friday, March 20, 2020 2:56 PM
> > To: devel@edk2.groups.io
> > Cc: Justen, Jordan L <jordan.l.justen@intel.com>; Andrew Fish
> > <afish@apple.com>; Ni, Ray <ray.ni@intel.com>
> > Subject: [PATCH] EmulatorPkg/WinHost: Add EFI_BUFFER_TOO_SMALL for
> > return status.
> >
> > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2605
> >
> > I think it is necessary that check the buffer size before ReadFile, it
> > will inform the caller that they should provide more buffer.
> >
> > Cc: Jordan Justen <jordan.l.justen@intel.com>
> > Cc: Andrew Fish <afish@apple.com>
> > Cc: Ray Ni <ray.ni@intel.com>
> > Signed-off-by: Guomin Jiang <guomin.jiang@intel.com>
> > ---
> >  EmulatorPkg/Win/Host/WinFileSystem.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/EmulatorPkg/Win/Host/WinFileSystem.c
> > b/EmulatorPkg/Win/Host/WinFileSystem.c
> > index f6b06b1c92..6fb86db6b3 100644
> > --- a/EmulatorPkg/Win/Host/WinFileSystem.c
> > +++ b/EmulatorPkg/Win/Host/WinFileSystem.c
> > @@ -1159,6 +1159,12 @@ WinNtFileRead (
> >        }
> >
> >      }
> >
> >
> >
> > +    if (FileSize > *BufferSize) {
> >
> > +      Status = EFI_BUFFER_TOO_SMALL;
> >
> > +      *BufferSize = FileSize;
> >
> > +      goto Done;
> >
> > +    }
> >
> > +
> >
> >      Status = ReadFile (
> >
> >        PrivateFile->LHandle,
> >
> >        Buffer,
> >
> > --
> > 2.25.1.windows.1