devpath.c revision 303975 
1/*-
2 * Copyright (c) 2016 John Baldwin <jhb@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: releng/11.0/sys/boot/efi/libefi/devpath.c 300780 2016-05-26 21:43:22Z jhb $");
29
30#include <efi.h>
31#include <efilib.h>
32
33/* XXX: This belongs in an efifoo.h header. */
34#define	EFI_LOADED_IMAGE_DEVICE_PATH_PROTOCOL_GUID			\
35    { 0xbc62157e, 0x3e33, 0x4fec, { 0x99, 0x20, 0x2d, 0x3b, 0x36, 0xd7, 0x50, 0xdf } }
36
37#define	EFI_DEVICE_PATH_TO_TEXT_PROTOCOL_GUID				\
38    { 0x8b843e20, 0x8132, 0x4852, { 0x90, 0xcc, 0x55, 0x1a, 0x4e, 0x4a, 0x7f, 0x1c } }
39
40INTERFACE_DECL(_EFI_DEVICE_PATH_PROTOCOL);
41
42typedef
43CHAR16*
44(EFIAPI *EFI_DEVICE_PATH_TO_TEXT_NODE) (
45    IN struct _EFI_DEVICE_PATH *This,
46    IN BOOLEAN                 DisplayOnly,
47    IN BOOLEAN                 AllowShortCuts
48    );
49
50typedef
51CHAR16*
52(EFIAPI *EFI_DEVICE_PATH_TO_TEXT_PATH) (
53    IN struct _EFI_DEVICE_PATH *This,
54    IN BOOLEAN                 DisplayOnly,
55    IN BOOLEAN                 AllowShortCuts
56    );
57
58typedef struct _EFI_DEVICE_PATH_TO_TEXT_PROTOCOL {
59	EFI_DEVICE_PATH_TO_TEXT_NODE ConvertDeviceNodeToText;
60	EFI_DEVICE_PATH_TO_TEXT_PATH ConvertDevicePathToText;
61} EFI_DEVICE_PATH_TO_TEXT_PROTOCOL;
62
63static EFI_GUID ImageDevicePathGUID =
64    EFI_LOADED_IMAGE_DEVICE_PATH_PROTOCOL_GUID;
65static EFI_GUID DevicePathGUID = DEVICE_PATH_PROTOCOL;
66static EFI_GUID DevicePathToTextGUID = EFI_DEVICE_PATH_TO_TEXT_PROTOCOL_GUID;
67static EFI_DEVICE_PATH_TO_TEXT_PROTOCOL *textProtocol;
68
69EFI_DEVICE_PATH *
70efi_lookup_image_devpath(EFI_HANDLE handle)
71{
72	EFI_DEVICE_PATH *devpath;
73	EFI_STATUS status;
74
75	status = BS->HandleProtocol(handle, &ImageDevicePathGUID,
76	    (VOID **)&devpath);
77	if (EFI_ERROR(status))
78		devpath = NULL;
79	return (devpath);
80}
81
82EFI_DEVICE_PATH *
83efi_lookup_devpath(EFI_HANDLE handle)
84{
85	EFI_DEVICE_PATH *devpath;
86	EFI_STATUS status;
87
88	status = BS->HandleProtocol(handle, &DevicePathGUID, (VOID **)&devpath);
89	if (EFI_ERROR(status))
90		devpath = NULL;
91	return (devpath);
92}
93
94CHAR16 *
95efi_devpath_name(EFI_DEVICE_PATH *devpath)
96{
97	static int once = 1;
98	EFI_STATUS status;
99
100	if (devpath == NULL)
101		return (NULL);
102	if (once) {
103		status = BS->LocateProtocol(&DevicePathToTextGUID, NULL,
104		    (VOID **)&textProtocol);
105		if (EFI_ERROR(status))
106			textProtocol = NULL;
107		once = 0;
108	}
109	if (textProtocol == NULL)
110		return (NULL);
111
112	return (textProtocol->ConvertDevicePathToText(devpath, TRUE, TRUE));
113}
114
115void
116efi_free_devpath_name(CHAR16 *text)
117{
118
119	BS->FreePool(text);
120}
121
122EFI_DEVICE_PATH *
123efi_devpath_last_node(EFI_DEVICE_PATH *devpath)
124{
125
126	if (IsDevicePathEnd(devpath))
127		return (NULL);
128	while (!IsDevicePathEnd(NextDevicePathNode(devpath)))
129		devpath = NextDevicePathNode(devpath);
130	return (devpath);
131}
132
133EFI_DEVICE_PATH *
134efi_devpath_trim(EFI_DEVICE_PATH *devpath)
135{
136	EFI_DEVICE_PATH *node, *copy;
137	size_t prefix, len;
138
139	node = efi_devpath_last_node(devpath);
140	prefix = (UINT8 *)node - (UINT8 *)devpath;
141	if (prefix == 0)
142		return (NULL);
143	len = prefix + DevicePathNodeLength(NextDevicePathNode(node));
144	copy = malloc(len);
145	memcpy(copy, devpath, prefix);
146	node = (EFI_DEVICE_PATH *)((UINT8 *)copy + prefix);
147	SetDevicePathEndNode(node);
148	return (copy);
149}
150
151EFI_HANDLE
152efi_devpath_handle(EFI_DEVICE_PATH *devpath)
153{
154	EFI_STATUS status;
155	EFI_HANDLE h;
156
157	/*
158	 * There isn't a standard way to locate a handle for a given
159	 * device path.  However, querying the EFI_DEVICE_PATH protocol
160	 * for a given device path should give us a handle for the
161	 * closest node in the path to the end that is valid.
162	 */
163	status = BS->LocateDevicePath(&DevicePathGUID, &devpath, &h);
164	if (EFI_ERROR(status))
165		return (NULL);
166	return (h);
167}
168