Re: UEFI Shell Lib Constructor and Shell Parameters Protocol

["Carsey, Jaben" <jaben.carsey@intel.com>]

Glad to help.  

I do not think that UEFI drivers really have the concept of command line parameters... they use other methods for configuration...

-Jaben

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> Jim.Dailey@dell.com
> Sent: Wednesday, April 05, 2017 8:21 AM
> To: Carsey, Jaben <jaben.carsey@intel.com>; Ni, Ruiyu <ruiyu.ni@intel.com>
> Cc: edk2-devel@lists.01.org
> Subject: Re: [edk2] UEFI Shell Lib Constructor and Shell Parameters Protocol
> Importance: High
> 
> Thanks, Jaben. That makes sense.
> 
> Now I see the real issue is with the "app" I ran across.  It is a driver,
> and it was trying to access command line args.  The driver crashed when
> it tried to access the command line, but it had been loaded in memory via
> the "load" command.
> 
> So, it seems "load" has no mechanism to pass command line arguments to a
> driver, and as a result, it apparently doesn't load the shell parameters
> protocol on the driver's handle, which caused the crash.
> 
> Regards,
> Jim
> 
> -----Original Message-----
> From: Carsey, Jaben [mailto:jaben.carsey@intel.com]
> Sent: Wednesday, April 5, 2017 10:08 AM
> To: Dailey, Jim <Jim_Dailey@Dell.com>; Ni, Ruiyu <ruiyu.ni@intel.com>
> Cc: edk2-devel@lists.01.org
> Subject: RE: UEFI Shell Lib Constructor and Shell Parameters Protocol
> 
> Jim,
> 
> That protocol must be installed on your applications own image handle for it
> to be valid.  Locating the protocol on some other image would result with
> finding the other image's command line parameters and the like...
> 
> -Jaben
> 
> 
> > -----Original Message-----
> > From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> > Jim.Dailey@dell.com
> > Sent: Wednesday, April 05, 2017 7:07 AM
> > To: Carsey, Jaben <jaben.carsey@intel.com>; Ni, Ruiyu
> <ruiyu.ni@intel.com>
> > Cc: edk2-devel@lists.01.org
> > Subject: [edk2] UEFI Shell Lib Constructor and Shell Parameters Protocol
> > Importance: High
> >
> >
> > A question or two for all shell experts:
> >
> > In the UEFI Shell Lib constructor code, if the Shell protocol cannot
> > be opened, then an attempt is made to locate it before "giving up".
> >
> > However, if the Shell parameters protocol cannot be opened, no attempt
> > is made to locate it---the code simply leaves the parameters protocol
> > pointer set to NULL. Can anyone explain why this is?
> >
> > I came across an app that crashes because of this behavior, but if I
> > add code to try and locate the parameters protocol, then the app works
> > as designed WRT accessing command line parameters.  Is there some
> > lurking issue if an attempt to locate the parameters protocol is made
> > and is successful?
> >
> > Thanks,
> > Jim
> >
> > -------
> > Here is the relevant code:
> >
> > EFI_STATUS
> > ShellLibConstructorWorker (
> >   IN EFI_HANDLE        ImageHandle,
> >   IN EFI_SYSTEM_TABLE  *SystemTable
> >   )
> > {
> >   EFI_STATUS  Status;
> >
> >   //
> >   // UEFI 2.0 shell interfaces (used preferentially)
> >   //
> >   Status = gBS->OpenProtocol(
> >     ImageHandle,
> >     &gEfiShellProtocolGuid,
> >     (VOID **)&gEfiShellProtocol,
> >     ImageHandle,
> >     NULL,
> >     EFI_OPEN_PROTOCOL_GET_PROTOCOL
> >    );
> >   if (EFI_ERROR(Status)) {
> >     //
> >     // Search for the shell protocol
> >     //
> >     Status = gBS->LocateProtocol(
> >       &gEfiShellProtocolGuid,
> >       NULL,
> >       (VOID **)&gEfiShellProtocol
> >      );
> >     if (EFI_ERROR(Status)) {
> >       gEfiShellProtocol = NULL;
> >     }
> >   }
> >   Status = gBS->OpenProtocol(
> >     ImageHandle,
> >     &gEfiShellParametersProtocolGuid,
> >     (VOID **)&gEfiShellParametersProtocol,
> >     ImageHandle,
> >     NULL,
> >     EFI_OPEN_PROTOCOL_GET_PROTOCOL
> >    );
> >   if (EFI_ERROR(Status)) {
> > #if 1 // _Dell_ : Search for the parameters protocol too!
> >     //
> >     // Search for the shell parameters protocol
> >     //
> >     Status = gBS->LocateProtocol(
> >       &gEfiShellParametersProtocolGuid,
> >       NULL,
> >       (VOID **)&gEfiShellParametersProtocol
> >      );
> >     if (EFI_ERROR(Status)) {
> >       gEfiShellParametersProtocol = NULL;
> >     }
> > #else
> >     gEfiShellParametersProtocol = NULL;
> > #endif
> >   }
> > ...
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