1 /*- 2 * Copyright (c) 2016 John Baldwin <[email protected]> 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("$FreeBSD$"); 29 30 #include <efi.h> 31 #include <efilib.h> 32 33 static EFI_GUID ImageDevicePathGUID = 34 EFI_LOADED_IMAGE_DEVICE_PATH_PROTOCOL_GUID; 35 static EFI_GUID DevicePathGUID = DEVICE_PATH_PROTOCOL; 36 static EFI_GUID DevicePathToTextGUID = EFI_DEVICE_PATH_TO_TEXT_PROTOCOL_GUID; 37 static EFI_DEVICE_PATH_TO_TEXT_PROTOCOL *textProtocol; 38 39 EFI_DEVICE_PATH * 40 efi_lookup_image_devpath(EFI_HANDLE handle) 41 { 42 EFI_DEVICE_PATH *devpath; 43 EFI_STATUS status; 44 45 status = OpenProtocolByHandle(handle, &ImageDevicePathGUID, 46 (void **)&devpath); 47 if (EFI_ERROR(status)) 48 devpath = NULL; 49 return (devpath); 50 } 51 52 EFI_DEVICE_PATH * 53 efi_lookup_devpath(EFI_HANDLE handle) 54 { 55 EFI_DEVICE_PATH *devpath; 56 EFI_STATUS status; 57 58 status = OpenProtocolByHandle(handle, &DevicePathGUID, 59 (void **)&devpath); 60 if (EFI_ERROR(status)) 61 devpath = NULL; 62 return (devpath); 63 } 64 65 CHAR16 * 66 efi_devpath_name(EFI_DEVICE_PATH *devpath) 67 { 68 static int once = 1; 69 EFI_STATUS status; 70 71 if (devpath == NULL) 72 return (NULL); 73 if (once) { 74 status = BS->LocateProtocol(&DevicePathToTextGUID, NULL, 75 (VOID **)&textProtocol); 76 if (EFI_ERROR(status)) 77 textProtocol = NULL; 78 once = 0; 79 } 80 if (textProtocol == NULL) 81 return (NULL); 82 83 return (textProtocol->ConvertDevicePathToText(devpath, TRUE, TRUE)); 84 } 85 86 void 87 efi_free_devpath_name(CHAR16 *text) 88 { 89 90 BS->FreePool(text); 91 } 92 93 EFI_DEVICE_PATH * 94 efi_devpath_last_node(EFI_DEVICE_PATH *devpath) 95 { 96 97 if (IsDevicePathEnd(devpath)) 98 return (NULL); 99 while (!IsDevicePathEnd(NextDevicePathNode(devpath))) 100 devpath = NextDevicePathNode(devpath); 101 return (devpath); 102 } 103 104 EFI_DEVICE_PATH * 105 efi_devpath_trim(EFI_DEVICE_PATH *devpath) 106 { 107 EFI_DEVICE_PATH *node, *copy; 108 size_t prefix, len; 109 110 if ((node = efi_devpath_last_node(devpath)) == NULL) 111 return (NULL); 112 prefix = (UINT8 *)node - (UINT8 *)devpath; 113 if (prefix == 0) 114 return (NULL); 115 len = prefix + DevicePathNodeLength(NextDevicePathNode(node)); 116 copy = malloc(len); 117 if (copy != NULL) { 118 memcpy(copy, devpath, prefix); 119 node = (EFI_DEVICE_PATH *)((UINT8 *)copy + prefix); 120 SetDevicePathEndNode(node); 121 } 122 return (copy); 123 } 124 125 EFI_HANDLE 126 efi_devpath_handle(EFI_DEVICE_PATH *devpath) 127 { 128 EFI_STATUS status; 129 EFI_HANDLE h; 130 131 /* 132 * There isn't a standard way to locate a handle for a given 133 * device path. However, querying the EFI_DEVICE_PATH protocol 134 * for a given device path should give us a handle for the 135 * closest node in the path to the end that is valid. 136 */ 137 status = BS->LocateDevicePath(&DevicePathGUID, &devpath, &h); 138 if (EFI_ERROR(status)) 139 return (NULL); 140 return (h); 141 } 142 143 bool 144 efi_devpath_match_node(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2) 145 { 146 size_t len; 147 148 if (devpath1 == NULL || devpath2 == NULL) 149 return (false); 150 if (DevicePathType(devpath1) != DevicePathType(devpath2) || 151 DevicePathSubType(devpath1) != DevicePathSubType(devpath2)) 152 return (false); 153 len = DevicePathNodeLength(devpath1); 154 if (len != DevicePathNodeLength(devpath2)) 155 return (false); 156 if (memcmp(devpath1, devpath2, len) != 0) 157 return (false); 158 return (true); 159 } 160 161 bool 162 efi_devpath_match(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2) 163 { 164 165 if (devpath1 == NULL || devpath2 == NULL) 166 return (false); 167 168 while (true) { 169 if (!efi_devpath_match_node(devpath1, devpath2)) 170 return false; 171 if (IsDevicePathEnd(devpath1)) 172 break; 173 devpath1 = NextDevicePathNode(devpath1); 174 devpath2 = NextDevicePathNode(devpath2); 175 } 176 return (true); 177 } 178 179 bool 180 efi_devpath_is_prefix(EFI_DEVICE_PATH *prefix, EFI_DEVICE_PATH *path) 181 { 182 size_t len; 183 184 if (prefix == NULL || path == NULL) 185 return (false); 186 187 while (1) { 188 if (IsDevicePathEnd(prefix)) 189 break; 190 191 if (DevicePathType(prefix) != DevicePathType(path) || 192 DevicePathSubType(prefix) != DevicePathSubType(path)) 193 return (false); 194 195 len = DevicePathNodeLength(prefix); 196 if (len != DevicePathNodeLength(path)) 197 return (false); 198 199 if (memcmp(prefix, path, len) != 0) 200 return (false); 201 202 prefix = NextDevicePathNode(prefix); 203 path = NextDevicePathNode(path); 204 } 205 return (true); 206 } 207 208 /* 209 * Skip over the 'prefix' part of path and return the part of the path 210 * that starts with the first node that's a MEDIA_DEVICE_PATH. 211 */ 212 EFI_DEVICE_PATH * 213 efi_devpath_to_media_path(EFI_DEVICE_PATH *path) 214 { 215 216 while (!IsDevicePathEnd(path)) { 217 if (DevicePathType(path) == MEDIA_DEVICE_PATH) 218 return (path); 219 path = NextDevicePathNode(path); 220 } 221 return (NULL); 222 } 223 224 UINTN 225 efi_devpath_length(EFI_DEVICE_PATH *path) 226 { 227 EFI_DEVICE_PATH *start = path; 228 229 while (!IsDevicePathEnd(path)) 230 path = NextDevicePathNode(path); 231 return ((UINTN)path - (UINTN)start) + DevicePathNodeLength(path); 232 } 233 234 EFI_HANDLE 235 efi_devpath_to_handle(EFI_DEVICE_PATH *path, EFI_HANDLE *handles, unsigned nhandles) 236 { 237 unsigned i; 238 EFI_DEVICE_PATH *media, *devpath; 239 EFI_HANDLE h; 240 241 media = efi_devpath_to_media_path(path); 242 if (media == NULL) 243 return (NULL); 244 for (i = 0; i < nhandles; i++) { 245 h = handles[i]; 246 devpath = efi_lookup_devpath(h); 247 if (devpath == NULL) 248 continue; 249 if (!efi_devpath_match_node(media, efi_devpath_to_media_path(devpath))) 250 continue; 251 return (h); 252 } 253 return (NULL); 254 } 255