1 /*- 2 * Copyright (c) 2016 John Baldwin <jhb@FreeBSD.org> 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 */ 25 26 #include <sys/cdefs.h> 27 __FBSDID("$FreeBSD$"); 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 * 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 * 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 * 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 85 efi_free_devpath_name(CHAR16 *text) 86 { 87 88 BS->FreePool(text); 89 } 90 91 EFI_DEVICE_PATH * 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 * 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 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 142 efi_devpath_match_node(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2) 143 { 144 size_t len; 145 146 if (devpath1 == NULL || devpath2 == NULL) 147 return (false); 148 if (DevicePathType(devpath1) != DevicePathType(devpath2) || 149 DevicePathSubType(devpath1) != DevicePathSubType(devpath2)) 150 return (false); 151 len = DevicePathNodeLength(devpath1); 152 if (len != DevicePathNodeLength(devpath2)) 153 return (false); 154 if (memcmp(devpath1, devpath2, len) != 0) 155 return (false); 156 return (true); 157 } 158 159 bool 160 efi_devpath_match(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2) 161 { 162 163 if (devpath1 == NULL || devpath2 == NULL) 164 return (false); 165 166 while (true) { 167 if (!efi_devpath_match_node(devpath1, devpath2)) 168 return false; 169 if (IsDevicePathEnd(devpath1)) 170 break; 171 devpath1 = NextDevicePathNode(devpath1); 172 devpath2 = NextDevicePathNode(devpath2); 173 } 174 return (true); 175 } 176 177 bool 178 efi_devpath_is_prefix(EFI_DEVICE_PATH *prefix, EFI_DEVICE_PATH *path) 179 { 180 size_t len; 181 182 if (prefix == NULL || path == NULL) 183 return (false); 184 185 while (1) { 186 if (IsDevicePathEnd(prefix)) 187 break; 188 189 if (DevicePathType(prefix) != DevicePathType(path) || 190 DevicePathSubType(prefix) != DevicePathSubType(path)) 191 return (false); 192 193 len = DevicePathNodeLength(prefix); 194 if (len != DevicePathNodeLength(path)) 195 return (false); 196 197 if (memcmp(prefix, path, len) != 0) 198 return (false); 199 200 prefix = NextDevicePathNode(prefix); 201 path = NextDevicePathNode(path); 202 } 203 return (true); 204 } 205 206 /* 207 * Skip over the 'prefix' part of path and return the part of the path 208 * that starts with the first node that's a MEDIA_DEVICE_PATH. 209 */ 210 EFI_DEVICE_PATH * 211 efi_devpath_to_media_path(EFI_DEVICE_PATH *path) 212 { 213 214 while (!IsDevicePathEnd(path)) { 215 if (DevicePathType(path) == MEDIA_DEVICE_PATH) 216 return (path); 217 path = NextDevicePathNode(path); 218 } 219 return (NULL); 220 } 221 222 UINTN 223 efi_devpath_length(EFI_DEVICE_PATH *path) 224 { 225 EFI_DEVICE_PATH *start = path; 226 227 while (!IsDevicePathEnd(path)) 228 path = NextDevicePathNode(path); 229 return ((UINTN)path - (UINTN)start) + DevicePathNodeLength(path); 230 } 231