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 * 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 * 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 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 * 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 104 efi_free_devpath_name(CHAR16 *text) 105 { 106 107 BS->FreePool(text); 108 } 109 110 EFI_DEVICE_PATH * 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 * 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 * 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 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 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 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