Re: [PATCH] ShellPkg: Create a homefilesystem environment variable

[Andrew Fish <afish@apple.com>]

> On Oct 4, 2018, at 10:07 AM, Laszlo Ersek <lersek@redhat.com> wrote:
> 
> On 10/03/18 20:17, Carsey, Jaben wrote:
>> Pushed.
>> c0b1f749ef1304810ed4ea58ded65b7f41d79d3e
> 
> Please give other reviewers a bit more time than ~2 hours, to comment on
> the patch. :)
> 
> I think I would have suggested an improvement (or a clarification about)
> the commit message. It says:
> 
>>> -----Original Message-----
>>> From: Carsey, Jaben
>>> Sent: Wednesday, October 03, 2018 11:15 AM
>>> To: 'Jim.Dailey@dell.com' <Jim.Dailey@dell.com>; edk2-devel@lists.01.org
>>> Subject: RE: [edk2] [PATCH] ShellPkg: Create a homefilesystem environment
>>> variable
>>> 
>>> Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>
>>> 
>>>> -----Original Message-----
>>>> From: Jim.Dailey@dell.com [mailto:Jim.Dailey@dell.com]
>>>> Sent: Wednesday, October 03, 2018 9:02 AM
>>>> To: edk2-devel@lists.01.org
>>>> Cc: Carsey, Jaben <jaben.carsey@intel.com>; Ni, Ruiyu
>>> <ruiyu.ni@intel.com>
>>>> Subject: [edk2] [PATCH] ShellPkg: Create a homefilesystem environment
>>>> variable
>>>> Importance: High
>>>> 
>>>> Create a homefilesystem environment variable whose value is the file
>>>> system on which the executing shell is located. For example: "FS14:".
> 
> that the file system in question contains the *shell*.
> 
> So my first question would have been, what if the shell is memory mapped
> (from a firmware volume), but the platform doesn't expose firmware
> filesystems (FFSs) as EFI simple file system protocol instances? In that
> case, the "file system on which the executing shell is located" seems
> ill-defined.
> 

Same if the Shell was network booted. 

Thanks,

Andrew Fish

>>>> 
>>>> This eliminates the need for people to have to try and find the "boot"
>>>> file system in their startup script.  After this change they can simply
> 
> Note, here the commit message refers to the startup script, not the
> shell itself.
> 
>>>> execute %homefilesystem% to set the cwd to the root of the file system
>>>> where the shell is located.
> 
> I think the commit message here misses a "CD" command.
> 
>>>> 
>>>> A future enhancement could be to add "homefilesystem" to the list of
>>>> predefined, read-only variables listed in the EfiShellSetEnv function of
>>>> file ShellProtocol.c
> 
> Is it OK with the UEFI shell spec to define a shell variable called
> "homefilesystem"? I seem to remember that edk2-specific options for
> standard UEFI shell commands generally start with an underscore, to
> avoid clashing with the standard namespace. Does that apply to shell
> variables perhaps? (This is mostly for my own education.)
> 
>>>> 
>>>> Contributed-under: TianoCore Contribution Agreement 1.1
>>>> Signed-off-by: Jim Dailey <jim_dailey@dell.com>
>>>> ---
>>>> ShellPkg/Application/Shell/Shell.c | 2 ++
>>>> 1 file changed, 2 insertions(+)
>>>> 
>>>> diff --git a/ShellPkg/Application/Shell/Shell.c
>>>> b/ShellPkg/Application/Shell/Shell.c
>>>> index 3f3bcbb4b0..6185b6ac80 100644
>>>> --- a/ShellPkg/Application/Shell/Shell.c
>>>> +++ b/ShellPkg/Application/Shell/Shell.c
>>>> @@ -1169,6 +1169,8 @@ LocateStartupScript (
>>>>       *TempSpot = CHAR_NULL;
>>>>     }
>>>> 
>>>> +    InternalEfiShellSetEnv(L"homefilesystem", StartupScriptPath, TRUE);
>>>> +
> 
> Again, this refers to the startup script, not the shell itself.
> 
>>>>     StartupScriptPath = StrnCatGrow (&StartupScriptPath, &Size,
>>>> ((FILEPATH_DEVICE_PATH *)FileDevicePath)->PathName, 0);
>>>>     PathRemoveLastItem (StartupScriptPath);
>>>>     StartupScriptPath = StrnCatGrow (&StartupScriptPath, &Size,
>>>> mStartupScript, 0);
>>>> --
>>>> 2.17.0.windows.1
>> 
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>> 
> 
> Thanks
> Laszlo
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