Michael,
Be careful as Length is an array. Your hang is probably a bad length. I would
recommend using the lib function, FileDevicePath().
https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2/MdePkg/Library/UefiDevicePathLib/UefiDevicePathLib.c
/**
Allocates a device path for a file and appends it to an existing device path.
If Device is a valid device handle that contains a device path protocol, then
a device path for
the file specified by FileName is allocated and appended to the device path
associated with the
handle Device. The allocated device path is returned. If Device is NULL or
Device is a handle
that does not support the device path protocol, then a device path containing
a single device
path node for the file specified by FileName is allocated and returned.
The memory for the new device path is allocated from EFI boot services
memory. It is the responsibility
of the caller to free the memory allocated.
If FileName is NULL, then ASSERT().
If FileName is not aligned on a 16-bit boundary, then ASSERT().
@param Device A pointer to a device handle. This
parameter
is optional and may be NULL.
@param FileName A pointer to a Null-terminated Unicode
string.
@return The allocated device path.
**/
EFI_DEVICE_PATH_PROTOCOL *
EFIAPI
FileDevicePath (
IN EFI_HANDLE Device, OPTIONAL
IN CONST CHAR16 *FileName
)
Andrew Fish
/**
This protocol can be used on any device handle to obtain generic
path/location
information concerning the physical device or logical device. If the handle
does
not logically map to a physical device, the handle may not necessarily
support
the device path protocol. The device path describes the location of the
device
the handle is for. The size of the Device Path can be determined from the
structures
that make up the Device Path.
**/
typedef struct {
UINT8 Type; ///< 0x01 Hardware Device Path.
///< 0x02 ACPI Device Path.
///< 0x03 Messaging Device Path.
///< 0x04 Media Device Path.
///< 0x05 BIOS Boot Specification Device Path.
///< 0x7F End of Hardware Device Path.
UINT8 SubType; ///< Varies by Type
///< 0xFF End Entire Device Path, or
///< 0x01 End This Instance of a Device Path and start a new
///< Device Path.
UINT8 Length[2]; ///< Specific Device Path data. Type and Sub-Type define
///< type of data. Size of data is included in Length.
} EFI_DEVICE_PATH_PROTOCOL;
On Oct 15, 2012, at 6:25 AM, Michael Lorer wrote:
> Hello,
>
> I’m trinying to load a EFI\BOOT\Bootx64.efi-image from a specific partition
> using the UEFI LoadImage() function.
> But I think I have some difficulties to build a correct DevicePath to the
> image.
> Right now I do it the following way, but the LoadImage() function gets stuck
> in a Deadloop:
>
> struct {
> EFI_DEVICE_PATH_PROTOCOL Header;
> CHAR16 FileName[22];
> EFI_DEVICE_PATH_PROTOCOL end;
> } ApplicationFilePath = {
> {
> MEDIA_DEVICE_PATH,
> MEDIA_FILEPATH_DP,
> 46
> },
> { L"EFI\\BOOT\\BOOTx64.EFI"},
> {
> END_DEVICE_PATH, END_ENTIRE_SUBTYPE,
> sizeof(EFI_DEVICE_PATH_PROTOCOL)
> }
> };
> EFI_DEVICE_PATH_PROTOCOL *pApplicationFilePath = (EFI_DEVICE_PATH_PROTOCOL
> *)&ApplicationFilePath;
>
> // Get all BlockIO-Protocols
> Status =
> pBS->LocateHandleBuffer(ByProtocol,&gEfiBlockIoProtocolGuid,NULL,&Count,&Handle);
>
> for( i=0; i<Count; i++ ){
> EFI_BLOCK_IO_PROTOCOL *BlockIo;
> EFI_DEVICE_PATH_PROTOCOL *PartitionDevicePath, *TmpDevicePath;
> EFI_DEVICE_PATH_PROTOCOL *pApplicationPath = NULL;
>
> Status = pBS->HandleProtocol(Handle[i],
> &gEfiDevicePathProtocolGuid, &PartitionDevicePath);
>
> // Get last node of the device path. It should be partition
> node
> PartitionNode = (HARDDRIVE_DEVICE_PATH*)PartitionDevicePath;
>
> for( TmpDevicePath = PartitionDevicePath;
> !EfiIsDevicePathEndType(TmpDevicePath);
> TmpDevicePath =
> EfiNextDevicePathNode(TmpDevicePath) )
> {
> PartitionNode =
> (HARDDRIVE_DEVICE_PATH*)TmpDevicePath;
> }
>
> // Here I'm looking for a specific partition and check some
> Header-Parameter
> if (PartitionNode->Header.Type != MEDIA_DEVICE_PATH ||
> PartitionNode->Header.SubType !=
> MEDIA_HARDDRIVE_DP ||
> PartitionNode->SignatureType != 0x02 ||
> MemCmp(&PartitionNode->Signature,
> gGuidOfASpecificPartition, sizeof(EFI_GUID)) != 0)
> continue;
>
> Status =
> pBS->LocateProtocol(&gEfiDevicePathUtilitiesProtocolGuid,
> NULL,(VOID**)&pDevicePathUtils);
>
> // Build the whole DevicePath
> pApplicationPath =
> pDevicePathUtils->AppendDevicePath(PartitionDevicePath,pApplicationFilePath);
>
> // Try to load the Image using the built DevicePath
> Status = pBS->LoadImage
> (TRUE,ImageHandle,pApplicationPath,NULL,0,&Handle);
> // But it resaults in a deadloop
> }
>
> I would appreciate any hints on what I’m missing.
>
> Thank you,
> Michael
> ------------------------------------------------------------------------------
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------------------------------------------------------------------------------
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Deploy New Relic app performance management and know exactly
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