Re: How to get BBS_BBS_DEVICE_PATH from BOOTXXXX variable

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

Have you examined the BCFG command in the UEFI Shell?  

It does this exact behavior and the code is at: ShellPkg\Library\UefiBcfgCommandLib\bcfg.c.

-Jaben

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> Saqib Khan
> Sent: Wednesday, October 19, 2016 11:18 AM
> To: Andrew Fish <afish@apple.com>
> Cc: edk2-devel@ml01.01.org; Laszlo Ersek <lersek@redhat.com>
> Subject: Re: [edk2] How to get BBS_BBS_DEVICE_PATH from BOOTXXXX
> variable
> 
> Hi, so i have parsed the structure as follow :
> 
> 
> 
> 
> 
> 
> 
> *BootVariable = mGetVariable(Name, &gEfiGlobalVariableGuid,
> &BootVariableSize, NULL);LDAttr = BootVariable[0];FilePathListLength =
> (BootVariable+2);Ptr = (BootVariable+3); // for description *
> 
> 
> 
> *for FilePathList[] Ptr+= StrSize((CHAR16 *)Ptr);         CopyMem (Ptr,
> DevicePath, *FilePathListLength);*
> 
> 
> I am able to get LDAttr ,FilePathListLength and description but
> 
> when i try to check DevicePath->Type it always return 0x01( Hardware Device
> Path) for each device .
> 
> 
> I have hard drive with legacy OS(BBS_DEVICE_PATH). So it should not always
> return 0x01 .What i am doing wrong in parsing ?
> 
> Thanks
> 
> On Tue, Oct 18, 2016 at 11:37 PM, Andrew Fish <afish@apple.com> wrote:
> 
> >
> > > On Oct 18, 2016, at 10:40 AM, Laszlo Ersek <lersek@redhat.com> wrote:
> > >
> > > On 10/18/16 19:18, Saqib Khan wrote:
> > >> Hi,
> > >> I can not find structure of BOOTXXXX variable, Can any one help how to
> > >> extract device path from BOOTXXXX variable.
> > >
> > > In UEFI-related questions, the UEFI specification has a fair chance to
> > > provide useful information.
> > >
> > > Please refer to "3.1.3 Load Options" in the UEFI v2.6 spec, available
> > > for download from <http://www.uefi.org/specifications>.
> > >
> > > Locating the matching structure definition in the edk2 tree is left as
> > > an exercise to the reader ;)
> > >
> >
> > Chapter 3 Boot Manager.
> >
> > The structure is EFI_LOAD_OPTION but some of the fields are variable
> > length so you have to do math to figure stuff out.
> >
> > Thanks,
> >
> > Andrew Fish
> >
> >
> > > Laszlo
> > >
> > > _______________________________________________
> > > edk2-devel mailing list
> > > edk2-devel@lists.01.org
> > > https://lists.01.org/mailman/listinfo/edk2-devel
> >
> >
> 
> 
> --
> Regards
> Saqib Ahmed Khanzada
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