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
29 #include <efi.h>
30 #include <efilib.h>
31 #include <efidevp.h>
32 #include <Protocol/DevicePath.h>
33 #include <Protocol/DevicePathFromText.h>
34 #include <Protocol/DevicePathToText.h>
35 #include <Protocol/LoadedImage.h>
36
37 EFI_GUID gEfiLoadedImageDevicePathProtocolGuid =
38 EFI_LOADED_IMAGE_DEVICE_PATH_PROTOCOL_GUID;
39 EFI_GUID gEfiDevicePathProtocolGuid = DEVICE_PATH_PROTOCOL;
40 EFI_GUID gEfiDevicePathToTextProtocolGuid =
41 EFI_DEVICE_PATH_TO_TEXT_PROTOCOL_GUID;
42 static EFI_DEVICE_PATH_TO_TEXT_PROTOCOL *textProtocol;
43
44 EFI_DEVICE_PATH *
efi_lookup_image_devpath(EFI_HANDLE handle)45 efi_lookup_image_devpath(EFI_HANDLE handle)
46 {
47 EFI_DEVICE_PATH *devpath;
48 EFI_STATUS status;
49
50 status = OpenProtocolByHandle(handle,
51 &gEfiLoadedImageDevicePathProtocolGuid,
52 (void **)&devpath);
53 if (EFI_ERROR(status))
54 devpath = NULL;
55 return (devpath);
56 }
57
58 EFI_DEVICE_PATH *
efi_lookup_devpath(EFI_HANDLE handle)59 efi_lookup_devpath(EFI_HANDLE handle)
60 {
61 EFI_DEVICE_PATH *devpath;
62 EFI_STATUS status;
63
64 status = OpenProtocolByHandle(handle, &gEfiDevicePathProtocolGuid,
65 (void **)&devpath);
66 if (EFI_ERROR(status))
67 devpath = NULL;
68 return (devpath);
69 }
70
71 void
efi_close_devpath(EFI_HANDLE handle)72 efi_close_devpath(EFI_HANDLE handle)
73 {
74 EFI_STATUS status;
75
76 status = BS->CloseProtocol(handle, &gEfiDevicePathProtocolGuid, IH,
77 NULL);
78 if (EFI_ERROR(status))
79 printf("CloseProtocol error: %lu\n", DECODE_ERROR(status));
80 }
81
82 CHAR16 *
efi_devpath_name(EFI_DEVICE_PATH * devpath)83 efi_devpath_name(EFI_DEVICE_PATH *devpath)
84 {
85 static bool once = true;
86 EFI_STATUS status;
87
88 if (devpath == NULL)
89 return (NULL);
90 if (once) {
91 status = BS->LocateProtocol(&gEfiDevicePathToTextProtocolGuid,
92 NULL, (void **)&textProtocol);
93 if (EFI_ERROR(status))
94 textProtocol = NULL;
95 once = false;
96 }
97 if (textProtocol == NULL)
98 return (NULL);
99
100 return (textProtocol->ConvertDevicePathToText(devpath, TRUE, TRUE));
101 }
102
103 void
efi_free_devpath_name(CHAR16 * text)104 efi_free_devpath_name(CHAR16 *text)
105 {
106
107 BS->FreePool(text);
108 }
109
110 EFI_DEVICE_PATH *
efi_devpath_last_node(EFI_DEVICE_PATH * devpath)111 efi_devpath_last_node(EFI_DEVICE_PATH *devpath)
112 {
113
114 if (IsDevicePathEnd(devpath))
115 return (NULL);
116 while (!IsDevicePathEnd(NextDevicePathNode(devpath)))
117 devpath = NextDevicePathNode(devpath);
118 return (devpath);
119 }
120
121 /*
122 * Walk device path nodes, return next instance or end node.
123 */
124 EFI_DEVICE_PATH *
efi_devpath_next_instance(EFI_DEVICE_PATH * devpath)125 efi_devpath_next_instance(EFI_DEVICE_PATH *devpath)
126 {
127 while (!IsDevicePathEnd(devpath)) {
128 devpath = NextDevicePathNode(devpath);
129 if (IsDevicePathEndType(devpath) &&
130 devpath->SubType == END_INSTANCE_DEVICE_PATH_SUBTYPE) {
131 devpath = NextDevicePathNode(devpath);
132 break;
133 }
134 }
135 return (devpath);
136 }
137
138 EFI_DEVICE_PATH *
efi_devpath_trim(EFI_DEVICE_PATH * devpath)139 efi_devpath_trim(EFI_DEVICE_PATH *devpath)
140 {
141 EFI_DEVICE_PATH *node, *copy;
142 size_t prefix, len;
143
144 if ((node = efi_devpath_last_node(devpath)) == NULL)
145 return (NULL);
146 prefix = (UINT8 *)node - (UINT8 *)devpath;
147 if (prefix == 0)
148 return (NULL);
149 len = prefix + DevicePathNodeLength(NextDevicePathNode(node));
150 copy = malloc(len);
151 if (copy != NULL) {
152 memcpy(copy, devpath, prefix);
153 node = (EFI_DEVICE_PATH *)((UINT8 *)copy + prefix);
154 SetDevicePathEndNode(node);
155 }
156 return (copy);
157 }
158
159 EFI_HANDLE
efi_devpath_handle(EFI_DEVICE_PATH * devpath)160 efi_devpath_handle(EFI_DEVICE_PATH *devpath)
161 {
162 EFI_STATUS status;
163 EFI_HANDLE h;
164
165 /*
166 * There isn't a standard way to locate a handle for a given
167 * device path. However, querying the EFI_DEVICE_PATH protocol
168 * for a given device path should give us a handle for the
169 * closest node in the path to the end that is valid.
170 */
171 status = BS->LocateDevicePath(&gEfiDevicePathProtocolGuid,
172 &devpath, &h);
173 if (EFI_ERROR(status))
174 return (NULL);
175 return (h);
176 }
177
178 bool
efi_devpath_match(EFI_DEVICE_PATH * devpath1,EFI_DEVICE_PATH * devpath2)179 efi_devpath_match(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2)
180 {
181 size_t len;
182
183 if (devpath1 == NULL || devpath2 == NULL)
184 return (false);
185
186 while (true) {
187 if (DevicePathType(devpath1) != DevicePathType(devpath2) ||
188 DevicePathSubType(devpath1) != DevicePathSubType(devpath2))
189 return (false);
190
191 len = DevicePathNodeLength(devpath1);
192 if (len != DevicePathNodeLength(devpath2))
193 return (false);
194
195 if (memcmp(devpath1, devpath2, len) != 0)
196 return (false);
197
198 if (IsDevicePathEnd(devpath1))
199 break;
200 devpath1 = NextDevicePathNode(devpath1);
201 devpath2 = NextDevicePathNode(devpath2);
202 }
203 return (true);
204 }
205
206 bool
efi_devpath_is_prefix(EFI_DEVICE_PATH * prefix,EFI_DEVICE_PATH * path)207 efi_devpath_is_prefix(EFI_DEVICE_PATH *prefix, EFI_DEVICE_PATH *path)
208 {
209 size_t len;
210
211 if (prefix == NULL || path == NULL)
212 return (false);
213
214 while (1) {
215 if (IsDevicePathEnd(prefix))
216 break;
217
218 if (DevicePathType(prefix) != DevicePathType(path) ||
219 DevicePathSubType(prefix) != DevicePathSubType(path))
220 return (false);
221
222 len = DevicePathNodeLength(prefix);
223 if (len != DevicePathNodeLength(path))
224 return (false);
225
226 if (memcmp(prefix, path, len) != 0)
227 return (false);
228
229 prefix = NextDevicePathNode(prefix);
230 path = NextDevicePathNode(path);
231 }
232 return (true);
233 }
234