Hi Laszlo, Thank you for the answer. It was helpful.
Considering option #1, can you give some more details (a small example or any reference link would be helpful), how I can use Shell APIs in my C file (which will compile to my .efi app)? Considering option #2, How I can find device path programatically from my C file? Thanks again for the help. :) With regards, Keshava On Tue, 27 Sep 2016 at 15:19 Laszlo Ersek <[email protected]> wrote: > On 09/27/16 11:25, GN Keshava wrote: > > Hi Laszlo, > > > > Thanks for the reply. I meant I have complete file path. I believe the > > "device path" is different. Is it possible to obtain DevicePath using my > > full file path? > > The pathname you seem to have (as "complete") is specific to a given > simple FS, so system-wide it cannot be considered complete (there can be > multiple filesystems). > > In your original email I missed that you started with "FS1:". Andrew's > answer covers that case. > > In summary, you can do three things: > - have a pathname that starts with FSx: (which is a shell-specific > mapping), and use Andrew's recommendation, > - have a complete UEFI device path, and then use what I recommended, > - have no information for selecting the filesystem (from the many > possible), and use your current iteration. > > Options #1 and #2 actually correspond to each other, considering > "expressive power" / information content (as long as you are in the > shell); please see the MAP shell command. > > Thanks > Laszlo > > > On Tue, 27 Sep 2016 at 14:46 Laszlo Ersek <[email protected] > > <mailto:[email protected]>> wrote: > > > > On 09/27/16 11:03, GN Keshava wrote: > > > Hi all, > > > > > > > > > I'm trying to open a file from my UEFI application. The path of > > file is > > > > > > fs1:/myfolder/myfile.txt > > > > > > 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. > > > > If you have a complete device path, you can use > gBS->LocateDevicePath() > > with gEfiSimpleFileSystemProtocolGuid, to locate the handle with the > > most specific device path (--> the longest device path prefix) with > the > > simple FS protocol installed on it. Then you can check if the > remaining > > device path (returned by the service) consist of nothing but one File > > Path Media Device Path node. If so, you can open the simple FS > protocol > > on the handle found, then use that to open the file by pathname. > > > > Laszlo > > > > _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
