697f4d59cc
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@3920 6f19259b-4bc3-4df7-8a09-765794883524
551 lines
18 KiB
C
551 lines
18 KiB
C
/** @file
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Device Path services. The thing to remember is device paths are built out of
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nodes. The device path is terminated by an end node that is length
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sizeof(EFI_DEVICE_PATH_PROTOCOL). That would be why there is sizeof(EFI_DEVICE_PATH_PROTOCOL)
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all over this file.
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The only place where multi-instance device paths are supported is in
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environment varibles. Multi-instance device paths should never be placed
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on a Handle.
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Copyright (c) 2006, Intel Corporation
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All rights reserved. This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include <Uefi.h>
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#include <Protocol/DevicePath.h>
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#include <Library/DevicePathLib.h>
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#include <Library/BaseMemoryLib.h>
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#include <Library/DebugLib.h>
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#include <Library/MemoryAllocationLib.h>
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#include <Library/UefiBootServicesTableLib.h>
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#include <Library/BaseLib.h>
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//
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// Template for an end-of-device path node.
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//
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STATIC EFI_DEVICE_PATH_PROTOCOL mEndDevicePath = {
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END_DEVICE_PATH_TYPE,
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END_ENTIRE_DEVICE_PATH_SUBTYPE,
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{
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END_DEVICE_PATH_LENGTH,
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0
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}
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};
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/**
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Returns the size of a device path in bytes.
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This function returns the size, in bytes, of the device path data structure specified by
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DevicePath including the end of device path node. If DevicePath is NULL, then 0 is returned.
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@param DevicePath A pointer to a device path data structure.
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@return The size of a device path in bytes.
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**/
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UINTN
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EFIAPI
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GetDevicePathSize (
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IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
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)
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{
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CONST EFI_DEVICE_PATH_PROTOCOL *Start;
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if (DevicePath == NULL) {
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return 0;
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}
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//
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// Search for the end of the device path structure
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//
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Start = DevicePath;
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while (!EfiIsDevicePathEnd (DevicePath)) {
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DevicePath = EfiNextDevicePathNode (DevicePath);
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}
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//
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// Compute the size and add back in the size of the end device path structure
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//
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return ((UINTN) DevicePath - (UINTN) Start) + sizeof (EFI_DEVICE_PATH_PROTOCOL);
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}
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/**
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Creates a new device path by appending a second device path to a first device path.
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This function allocates space for a new copy of the device path specified by DevicePath. If
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DevicePath is NULL, then NULL is returned. If the memory is successfully allocated, then the
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contents of DevicePath are copied to the newly allocated buffer, and a pointer to that buffer
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is returned. Otherwise, NULL is returned.
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@param DevicePath A pointer to a device path data structure.
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@return A pointer to the duplicated device path.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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DuplicateDevicePath (
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IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
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)
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{
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EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
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UINTN Size;
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//
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// Compute the size
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//
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Size = GetDevicePathSize (DevicePath);
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if (Size == 0) {
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return NULL;
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}
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//
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// Allocate space for duplicate device path
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//
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NewDevicePath = AllocateCopyPool (Size, DevicePath);
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return NewDevicePath;
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}
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/**
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Creates a new device path by appending a second device path to a first device path.
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This function creates a new device path by appending a copy of SecondDevicePath to a copy of
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FirstDevicePath in a newly allocated buffer. Only the end-of-device-path device node from
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SecondDevicePath is retained. The newly created device path is returned.
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If FirstDevicePath is NULL, then it is ignored, and a duplicate of SecondDevicePath is returned.
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If SecondDevicePath is NULL, then it is ignored, and a duplicate of FirstDevicePath is returned.
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If both FirstDevicePath and SecondDevicePath are NULL, then a copy of an end-of-device-path is
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returned.
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If there is not enough memory for the newly allocated buffer, then NULL is returned.
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The memory for the new device path is allocated from EFI boot services memory. It is the
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responsibility of the caller to free the memory allocated.
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@param FirstDevicePath A pointer to a device path data structure.
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@param SecondDevicePath A pointer to a device path data structure.
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@return A pointer to the new device path.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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AppendDevicePath (
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IN CONST EFI_DEVICE_PATH_PROTOCOL *FirstDevicePath, OPTIONAL
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IN CONST EFI_DEVICE_PATH_PROTOCOL *SecondDevicePath OPTIONAL
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)
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{
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UINTN Size;
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UINTN Size1;
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UINTN Size2;
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EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
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EFI_DEVICE_PATH_PROTOCOL *DevicePath2;
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//
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// If there's only 1 path, just duplicate it.
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//
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if (FirstDevicePath == NULL) {
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return DuplicateDevicePath ((SecondDevicePath != NULL) ? SecondDevicePath : &mEndDevicePath);
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}
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if (SecondDevicePath == NULL) {
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return DuplicateDevicePath (FirstDevicePath);
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}
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//
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// Allocate space for the combined device path. It only has one end node of
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// length EFI_DEVICE_PATH_PROTOCOL.
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//
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Size1 = GetDevicePathSize (FirstDevicePath);
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Size2 = GetDevicePathSize (SecondDevicePath);
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Size = Size1 + Size2 - sizeof (EFI_DEVICE_PATH_PROTOCOL);
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NewDevicePath = AllocatePool (Size);
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if (NewDevicePath != NULL) {
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NewDevicePath = CopyMem (NewDevicePath, FirstDevicePath, Size1);
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//
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// Over write FirstDevicePath EndNode and do the copy
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//
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DevicePath2 = (EFI_DEVICE_PATH_PROTOCOL *) ((CHAR8 *) NewDevicePath +
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(Size1 - sizeof (EFI_DEVICE_PATH_PROTOCOL)));
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CopyMem (DevicePath2, SecondDevicePath, Size2);
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}
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return NewDevicePath;
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}
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/**
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Creates a new path by appending the device node to the device path.
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This function creates a new device path by appending a copy of the device node specified by
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DevicePathNode to a copy of the device path specified by DevicePath in an allocated buffer.
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The end-of-device-path device node is moved after the end of the appended device node.
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If DevicePathNode is NULL then a copy of DevicePath is returned.
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If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device path device
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node is returned.
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If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path device node
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is returned.
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If there is not enough memory to allocate space for the new device path, then NULL is returned.
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The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
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free the memory allocated.
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@param DevicePath A pointer to a device path data structure.
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@param DevicePathNode A pointer to a single device path node.
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@return A pointer to the new device path.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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AppendDevicePathNode (
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IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
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IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathNode OPTIONAL
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)
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{
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EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;
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EFI_DEVICE_PATH_PROTOCOL *NextNode;
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EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
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UINTN NodeLength;
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if (DevicePathNode == NULL) {
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return DuplicateDevicePath ((DevicePath != NULL) ? DevicePath : &mEndDevicePath);
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}
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//
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// Build a Node that has a terminator on it
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//
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NodeLength = DevicePathNodeLength (DevicePathNode);
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TempDevicePath = AllocatePool (NodeLength + sizeof (EFI_DEVICE_PATH_PROTOCOL));
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if (TempDevicePath == NULL) {
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return NULL;
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}
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TempDevicePath = CopyMem (TempDevicePath, DevicePathNode, NodeLength);
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//
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// Add and end device path node to convert Node to device path
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//
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NextNode = NextDevicePathNode (TempDevicePath);
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SetDevicePathEndNode (NextNode);
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//
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// Append device paths
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//
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NewDevicePath = AppendDevicePath (DevicePath, TempDevicePath);
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FreePool (TempDevicePath);
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return NewDevicePath;
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}
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/**
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Creates a new device path by appending the specified device path instance to the specified device
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path.
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This function creates a new device path by appending a copy of the device path instance specified
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by DevicePathInstance to a copy of the device path secified by DevicePath in a allocated buffer.
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The end-of-device-path device node is moved after the end of the appended device path instance
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and a new end-of-device-path-instance node is inserted between.
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If DevicePath is NULL, then a copy if DevicePathInstance is returned.
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If DevicePathInstance is NULL, then NULL is returned.
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If there is not enough memory to allocate space for the new device path, then NULL is returned.
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The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
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free the memory allocated.
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@param DevicePath A pointer to a device path data structure.
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@param DevicePathInstance A pointer to a device path instance.
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@return A pointer to the new device path.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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AppendDevicePathInstance (
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IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
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IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathInstance OPTIONAL
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)
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{
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EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
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EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;
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UINTN SrcSize;
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UINTN InstanceSize;
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if (DevicePath == NULL) {
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return DuplicateDevicePath (DevicePathInstance);
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}
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if (DevicePathInstance == NULL) {
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return NULL;
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}
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SrcSize = GetDevicePathSize (DevicePath);
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InstanceSize = GetDevicePathSize (DevicePathInstance);
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NewDevicePath = AllocatePool (SrcSize + InstanceSize);
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if (NewDevicePath != NULL) {
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TempDevicePath = CopyMem (NewDevicePath, DevicePath, SrcSize);;
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while (!IsDevicePathEnd (TempDevicePath)) {
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TempDevicePath = NextDevicePathNode (TempDevicePath);
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}
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TempDevicePath->SubType = END_INSTANCE_DEVICE_PATH_SUBTYPE;
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TempDevicePath = NextDevicePathNode (TempDevicePath);
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CopyMem (TempDevicePath, DevicePathInstance, InstanceSize);
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}
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return NewDevicePath;
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}
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/**
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Creates a copy of the current device path instance and returns a pointer to the next device path
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instance.
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This function creates a copy of the current device path instance. It also updates DevicePath to
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point to the next device path instance in the device path (or NULL if no more) and updates Size
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to hold the size of the device path instance copy.
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If DevicePath is NULL, then NULL is returned.
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If there is not enough memory to allocate space for the new device path, then NULL is returned.
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The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
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free the memory allocated.
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If Size is NULL, then ASSERT().
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@param DevicePath On input, this holds the pointer to the current device path
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instance. On output, this holds the pointer to the next device
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path instance or NULL if there are no more device path
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instances in the device path pointer to a device path data
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structure.
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@param Size On output, this holds the size of the device path instance, in
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bytes or zero, if DevicePath is NULL.
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@return A pointer to the current device path instance.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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GetNextDevicePathInstance (
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IN OUT EFI_DEVICE_PATH_PROTOCOL **DevicePath,
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OUT UINTN *Size
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)
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{
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EFI_DEVICE_PATH_PROTOCOL *DevPath;
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EFI_DEVICE_PATH_PROTOCOL *ReturnValue;
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UINT8 Temp;
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ASSERT (Size != NULL);
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if (DevicePath == NULL || *DevicePath == NULL) {
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*Size = 0;
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return NULL;
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}
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//
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// Find the end of the device path instance
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//
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DevPath = *DevicePath;
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while (!IsDevicePathEndType (DevPath)) {
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DevPath = NextDevicePathNode (DevPath);
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}
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//
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// Compute the size of the device path instance
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//
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*Size = ((UINTN) DevPath - (UINTN) (*DevicePath)) + sizeof (EFI_DEVICE_PATH_PROTOCOL);
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//
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// Make a copy and return the device path instance
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//
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Temp = DevPath->SubType;
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DevPath->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
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ReturnValue = DuplicateDevicePath (*DevicePath);
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DevPath->SubType = Temp;
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//
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// If DevPath is the end of an entire device path, then another instance
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// does not follow, so *DevicePath is set to NULL.
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//
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if (DevicePathSubType (DevPath) == END_ENTIRE_DEVICE_PATH_SUBTYPE) {
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*DevicePath = NULL;
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} else {
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*DevicePath = NextDevicePathNode (DevPath);
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}
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return ReturnValue;
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}
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/**
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Creates a copy of the current device path instance and returns a pointer to the next device path
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instance.
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This function creates a new device node in a newly allocated buffer of size NodeLength and
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initializes the device path node header with NodeType and NodeSubType. The new device path node
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is returned.
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If NodeLength is smaller than a device path header, then NULL is returned.
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If there is not enough memory to allocate space for the new device path, then NULL is returned.
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The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
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free the memory allocated.
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@param NodeType The device node type for the new device node.
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@param NodeSubType The device node sub-type for the new device node.
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@param NodeLength The length of the new device node.
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@return The new device path.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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CreateDeviceNode (
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IN UINT8 NodeType,
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IN UINT8 NodeSubType,
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IN UINT16 NodeLength
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)
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{
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EFI_DEVICE_PATH_PROTOCOL *DevicePath;
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if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
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//
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// NodeLength is less than the size of the header.
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//
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return NULL;
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}
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DevicePath = AllocatePool (NodeLength);
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if (DevicePath != NULL) {
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DevicePath->Type = NodeType;
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DevicePath->SubType = NodeSubType;
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SetDevicePathNodeLength (DevicePath, NodeLength);
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}
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return DevicePath;
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}
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/**
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Determines if a device path is single or multi-instance.
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This function returns TRUE if the device path specified by DevicePath is multi-instance.
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Otherwise, FALSE is returned. If DevicePath is NULL, then FALSE is returned.
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@param DevicePath A pointer to a device path data structure.
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@retval TRUE DevicePath is multi-instance.
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@retval FALSE DevicePath is not multi-instance or DevicePath is NULL.
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**/
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BOOLEAN
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EFIAPI
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IsDevicePathMultiInstance (
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IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
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)
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{
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CONST EFI_DEVICE_PATH_PROTOCOL *Node;
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if (DevicePath == NULL) {
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return FALSE;
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}
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Node = DevicePath;
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while (!EfiIsDevicePathEnd (Node)) {
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if (EfiIsDevicePathEndInstance (Node)) {
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return TRUE;
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}
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Node = EfiNextDevicePathNode (Node);
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}
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return FALSE;
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}
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/**
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Retrieves the device path protocol from a handle.
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This function returns the device path protocol from the handle specified by Handle. If Handle is
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NULL or Handle does not contain a device path protocol, then NULL is returned.
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@param Handle The handle from which to retrieve the device path protocol.
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@return The device path protocol from the handle specified by Handle.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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DevicePathFromHandle (
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IN EFI_HANDLE Handle
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)
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{
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EFI_DEVICE_PATH_PROTOCOL *DevicePath;
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EFI_STATUS Status;
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Status = gBS->HandleProtocol (
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Handle,
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&gEfiDevicePathProtocolGuid,
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(VOID *) &DevicePath
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);
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if (EFI_ERROR (Status)) {
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DevicePath = NULL;
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}
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return DevicePath;
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}
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/**
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Allocates a device path for a file and appends it to an existing device path.
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If Device is a valid device handle that contains a device path protocol, then a device path for
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the file specified by FileName is allocated and appended to the device path associated with the
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handle Device. The allocated device path is returned. If Device is NULL or Device is a handle
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that does not support the device path protocol, then a device path containing a single device
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path node for the file specified by FileName is allocated and returned.
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If FileName is NULL, then ASSERT().
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@param Device A pointer to a device handle. This parameter is optional and
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may be NULL.
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@param FileName A pointer to a Null-terminated Unicode string.
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@return The allocated device path.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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FileDevicePath (
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IN EFI_HANDLE Device, OPTIONAL
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IN CONST CHAR16 *FileName
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)
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{
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UINTN Size;
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FILEPATH_DEVICE_PATH *FilePath;
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EFI_DEVICE_PATH_PROTOCOL *DevicePath;
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EFI_DEVICE_PATH_PROTOCOL *FileDevicePath;
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DevicePath = NULL;
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Size = StrSize (FileName);
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FileDevicePath = AllocatePool (Size + SIZE_OF_FILEPATH_DEVICE_PATH + EFI_END_DEVICE_PATH_LENGTH);
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if (FileDevicePath != NULL) {
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FilePath = (FILEPATH_DEVICE_PATH *) FileDevicePath;
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FilePath->Header.Type = MEDIA_DEVICE_PATH;
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FilePath->Header.SubType = MEDIA_FILEPATH_DP;
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CopyMem (&FilePath->PathName, FileName, Size);
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|
SetDevicePathNodeLength (&FilePath->Header, Size + SIZE_OF_FILEPATH_DEVICE_PATH);
|
|
SetDevicePathEndNode (NextDevicePathNode (&FilePath->Header));
|
|
|
|
if (Device != NULL) {
|
|
DevicePath = DevicePathFromHandle (Device);
|
|
}
|
|
|
|
DevicePath = AppendDevicePath (DevicePath, FileDevicePath);
|
|
FreePool (FileDevicePath);
|
|
}
|
|
|
|
return DevicePath;
|
|
}
|
|
|