Re: How to open a file by it's full path in UEFI

[GN Keshava <keshava.gn@gmail.com>]

Hi Andrew,

Thanks for the reply.

Can you tell more about (or some links) about the Shell APIs that you have
mentioned? Is it possible to access these from my C code? (not script, its
C code for my .efi app).

Also, can you give more idea about how I can map my volume name to device
path in my C file?

Thanks.
With regards,
Keshava

On Tue, 27 Sep 2016 at 14:37 Andrew Fish <afish@apple.com> wrote:

> On Sep 27, 2016, at 2:03 AM, GN Keshava <keshava.gn@gmail.com> wrote:
>
> Hi all,
>
>
> I'm trying to open a file from my UEFI application. The path of file is
>
> fs1:/myfolder/myfile.txt
>
>
> Keshava,
>
> The volume names are EFI Shell concepts, not UEFI Firmware concepts.
> Basically the Shell uses "fs1:" to match one of the Simple File System
> Handles. There is also an EFI Device Path on the handle with the Simple
> File System Handle and that is what maps to "fs1".
>
> So if you want to use these shell volume names you need to use Shell APIs.
>
> Thanks,
>
> Andrew Fish
>
>
> The code :
>
> efiStatus = bs->LocateHandleBuffer(ByProtocol,
>                                   &sfspGuid,
>                                   NULL,
>                                   &handleCount,
>                                   &handles);
>
> for (index = 0; index < (int)handleCount; ++ index)
> {
>    EFI_SIMPLE_FILE_SYSTEM_PROTOCOL* fs = NULL;
>
>    efiStatus = bs->HandleProtocol(
>        handles[index],
>        &sfspGuid,
>        (void**)&fs);
>
>    EFI_FILE_PROTOCOL* root = NULL;
>    ...
>    efiStatus = fs->OpenVolume(fs, &root);
>
>    EFI_FILE_PROTOCOL* token = NULL;
>
>    efiStatus = root->Open(
>        root,
>        &token,
>        L"myfolder\\myfile.txt",
>        EFI_FILE_MODE_READ,
>        EFI_FILE_READ_ONLY | EFI_FILE_HIDDEN | EFI_FILE_SYSTEM);
> }
>
> But using this method, I can only go through all the file system handles
> and open each volume and try opening my file.
>
> But I want to give full path to my file and open it in it's volume.
>
> How can I acheive this?
> Thanks.
> With regards,
> Keshava GN
>
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