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
32 static EFI_GUID ImageDevicePathGUID =
33 EFI_LOADED_IMAGE_DEVICE_PATH_PROTOCOL_GUID;
34 static EFI_GUID DevicePathGUID = DEVICE_PATH_PROTOCOL;
35 static EFI_GUID DevicePathToTextGUID = EFI_DEVICE_PATH_TO_TEXT_PROTOCOL_GUID;
36 static EFI_DEVICE_PATH_TO_TEXT_PROTOCOL *textProtocol;
37
38 EFI_DEVICE_PATH *
efi_lookup_image_devpath(EFI_HANDLE handle)39 efi_lookup_image_devpath(EFI_HANDLE handle)
40 {
41 EFI_DEVICE_PATH *devpath;
42 EFI_STATUS status;
43
44 status = BS->HandleProtocol(handle, &ImageDevicePathGUID,
45 (VOID **)&devpath);
46 if (EFI_ERROR(status))
47 devpath = NULL;
48 return (devpath);
49 }
50
51 EFI_DEVICE_PATH *
efi_lookup_devpath(EFI_HANDLE handle)52 efi_lookup_devpath(EFI_HANDLE handle)
53 {
54 EFI_DEVICE_PATH *devpath;
55 EFI_STATUS status;
56
57 status = BS->HandleProtocol(handle, &DevicePathGUID, (VOID **)&devpath);
58 if (EFI_ERROR(status))
59 devpath = NULL;
60 return (devpath);
61 }
62
63 CHAR16 *
efi_devpath_name(EFI_DEVICE_PATH * devpath)64 efi_devpath_name(EFI_DEVICE_PATH *devpath)
65 {
66 static int once = 1;
67 EFI_STATUS status;
68
69 if (devpath == NULL)
70 return (NULL);
71 if (once) {
72 status = BS->LocateProtocol(&DevicePathToTextGUID, NULL,
73 (VOID **)&textProtocol);
74 if (EFI_ERROR(status))
75 textProtocol = NULL;
76 once = 0;
77 }
78 if (textProtocol == NULL)
79 return (NULL);
80
81 return (textProtocol->ConvertDevicePathToText(devpath, TRUE, TRUE));
82 }
83
84 void
efi_free_devpath_name(CHAR16 * text)85 efi_free_devpath_name(CHAR16 *text)
86 {
87
88 BS->FreePool(text);
89 }
90
91 EFI_DEVICE_PATH *
efi_devpath_last_node(EFI_DEVICE_PATH * devpath)92 efi_devpath_last_node(EFI_DEVICE_PATH *devpath)
93 {
94
95 if (IsDevicePathEnd(devpath))
96 return (NULL);
97 while (!IsDevicePathEnd(NextDevicePathNode(devpath)))
98 devpath = NextDevicePathNode(devpath);
99 return (devpath);
100 }
101
102 EFI_DEVICE_PATH *
efi_devpath_trim(EFI_DEVICE_PATH * devpath)103 efi_devpath_trim(EFI_DEVICE_PATH *devpath)
104 {
105 EFI_DEVICE_PATH *node, *copy;
106 size_t prefix, len;
107
108 if ((node = efi_devpath_last_node(devpath)) == NULL)
109 return (NULL);
110 prefix = (UINT8 *)node - (UINT8 *)devpath;
111 if (prefix == 0)
112 return (NULL);
113 len = prefix + DevicePathNodeLength(NextDevicePathNode(node));
114 copy = malloc(len);
115 if (copy != NULL) {
116 memcpy(copy, devpath, prefix);
117 node = (EFI_DEVICE_PATH *)((UINT8 *)copy + prefix);
118 SetDevicePathEndNode(node);
119 }
120 return (copy);
121 }
122
123 EFI_HANDLE
efi_devpath_handle(EFI_DEVICE_PATH * devpath)124 efi_devpath_handle(EFI_DEVICE_PATH *devpath)
125 {
126 EFI_STATUS status;
127 EFI_HANDLE h;
128
129 /*
130 * There isn't a standard way to locate a handle for a given
131 * device path. However, querying the EFI_DEVICE_PATH protocol
132 * for a given device path should give us a handle for the
133 * closest node in the path to the end that is valid.
134 */
135 status = BS->LocateDevicePath(&DevicePathGUID, &devpath, &h);
136 if (EFI_ERROR(status))
137 return (NULL);
138 return (h);
139 }
140
141 bool
efi_devpath_match(EFI_DEVICE_PATH * devpath1,EFI_DEVICE_PATH * devpath2)142 efi_devpath_match(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2)
143 {
144 size_t len;
145
146 if (devpath1 == NULL || devpath2 == NULL)
147 return (false);
148
149 while (true) {
150 if (DevicePathType(devpath1) != DevicePathType(devpath2) ||
151 DevicePathSubType(devpath1) != DevicePathSubType(devpath2))
152 return (false);
153
154 len = DevicePathNodeLength(devpath1);
155 if (len != DevicePathNodeLength(devpath2))
156 return (false);
157
158 if (memcmp(devpath1, devpath2, len) != 0)
159 return (false);
160
161 if (IsDevicePathEnd(devpath1))
162 break;
163 devpath1 = NextDevicePathNode(devpath1);
164 devpath2 = NextDevicePathNode(devpath2);
165 }
166 return (true);
167 }
168
169 bool
efi_devpath_is_prefix(EFI_DEVICE_PATH * prefix,EFI_DEVICE_PATH * path)170 efi_devpath_is_prefix(EFI_DEVICE_PATH *prefix, EFI_DEVICE_PATH *path)
171 {
172 size_t len;
173
174 if (prefix == NULL || path == NULL)
175 return (false);
176
177 while (1) {
178 if (IsDevicePathEnd(prefix))
179 break;
180
181 if (DevicePathType(prefix) != DevicePathType(path) ||
182 DevicePathSubType(prefix) != DevicePathSubType(path))
183 return (false);
184
185 len = DevicePathNodeLength(prefix);
186 if (len != DevicePathNodeLength(path))
187 return (false);
188
189 if (memcmp(prefix, path, len) != 0)
190 return (false);
191
192 prefix = NextDevicePathNode(prefix);
193 path = NextDevicePathNode(path);
194 }
195 return (true);
196 }
197