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 = OpenProtocolByHandle(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 = OpenProtocolByHandle(handle, &DevicePathGUID,
58 (void **)&devpath);
59 if (EFI_ERROR(status))
60 devpath = NULL;
61 return (devpath);
62 }
63
64 void
efi_close_devpath(EFI_HANDLE handle)65 efi_close_devpath(EFI_HANDLE handle)
66 {
67 EFI_STATUS status;
68
69 status = BS->CloseProtocol(handle, &DevicePathGUID, IH, NULL);
70 if (EFI_ERROR(status))
71 printf("CloseProtocol error: %lu\n", EFI_ERROR_CODE(status));
72 }
73
74 CHAR16 *
efi_devpath_name(EFI_DEVICE_PATH * devpath)75 efi_devpath_name(EFI_DEVICE_PATH *devpath)
76 {
77 static int once = 1;
78 EFI_STATUS status;
79
80 if (devpath == NULL)
81 return (NULL);
82 if (once) {
83 status = BS->LocateProtocol(&DevicePathToTextGUID, NULL,
84 (VOID **)&textProtocol);
85 if (EFI_ERROR(status))
86 textProtocol = NULL;
87 once = 0;
88 }
89 if (textProtocol == NULL)
90 return (NULL);
91
92 return (textProtocol->ConvertDevicePathToText(devpath, TRUE, TRUE));
93 }
94
95 void
efi_free_devpath_name(CHAR16 * text)96 efi_free_devpath_name(CHAR16 *text)
97 {
98
99 BS->FreePool(text);
100 }
101
102 EFI_DEVICE_PATH *
efi_devpath_last_node(EFI_DEVICE_PATH * devpath)103 efi_devpath_last_node(EFI_DEVICE_PATH *devpath)
104 {
105
106 if (IsDevicePathEnd(devpath))
107 return (NULL);
108 while (!IsDevicePathEnd(NextDevicePathNode(devpath)))
109 devpath = NextDevicePathNode(devpath);
110 return (devpath);
111 }
112
113 EFI_DEVICE_PATH *
efi_devpath_trim(EFI_DEVICE_PATH * devpath)114 efi_devpath_trim(EFI_DEVICE_PATH *devpath)
115 {
116 EFI_DEVICE_PATH *node, *copy;
117 size_t prefix, len;
118
119 if ((node = efi_devpath_last_node(devpath)) == NULL)
120 return (NULL);
121 prefix = (UINT8 *)node - (UINT8 *)devpath;
122 if (prefix == 0)
123 return (NULL);
124 len = prefix + DevicePathNodeLength(NextDevicePathNode(node));
125 copy = malloc(len);
126 if (copy != NULL) {
127 memcpy(copy, devpath, prefix);
128 node = (EFI_DEVICE_PATH *)((UINT8 *)copy + prefix);
129 SetDevicePathEndNode(node);
130 }
131 return (copy);
132 }
133
134 EFI_HANDLE
efi_devpath_handle(EFI_DEVICE_PATH * devpath)135 efi_devpath_handle(EFI_DEVICE_PATH *devpath)
136 {
137 EFI_STATUS status;
138 EFI_HANDLE h;
139
140 /*
141 * There isn't a standard way to locate a handle for a given
142 * device path. However, querying the EFI_DEVICE_PATH protocol
143 * for a given device path should give us a handle for the
144 * closest node in the path to the end that is valid.
145 */
146 status = BS->LocateDevicePath(&DevicePathGUID, &devpath, &h);
147 if (EFI_ERROR(status))
148 return (NULL);
149 return (h);
150 }
151
152 bool
efi_devpath_match(EFI_DEVICE_PATH * devpath1,EFI_DEVICE_PATH * devpath2)153 efi_devpath_match(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2)
154 {
155 size_t len;
156
157 if (devpath1 == NULL || devpath2 == NULL)
158 return (false);
159
160 while (true) {
161 if (DevicePathType(devpath1) != DevicePathType(devpath2) ||
162 DevicePathSubType(devpath1) != DevicePathSubType(devpath2))
163 return (false);
164
165 len = DevicePathNodeLength(devpath1);
166 if (len != DevicePathNodeLength(devpath2))
167 return (false);
168
169 if (memcmp(devpath1, devpath2, len) != 0)
170 return (false);
171
172 if (IsDevicePathEnd(devpath1))
173 break;
174 devpath1 = NextDevicePathNode(devpath1);
175 devpath2 = NextDevicePathNode(devpath2);
176 }
177 return (true);
178 }
179
180 bool
efi_devpath_is_prefix(EFI_DEVICE_PATH * prefix,EFI_DEVICE_PATH * path)181 efi_devpath_is_prefix(EFI_DEVICE_PATH *prefix, EFI_DEVICE_PATH *path)
182 {
183 size_t len;
184
185 if (prefix == NULL || path == NULL)
186 return (false);
187
188 while (1) {
189 if (IsDevicePathEnd(prefix))
190 break;
191
192 if (DevicePathType(prefix) != DevicePathType(path) ||
193 DevicePathSubType(prefix) != DevicePathSubType(path))
194 return (false);
195
196 len = DevicePathNodeLength(prefix);
197 if (len != DevicePathNodeLength(path))
198 return (false);
199
200 if (memcmp(prefix, path, len) != 0)
201 return (false);
202
203 prefix = NextDevicePathNode(prefix);
204 path = NextDevicePathNode(path);
205 }
206 return (true);
207 }
208