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 * 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 * 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 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 * 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 96 efi_free_devpath_name(CHAR16 *text) 97 { 98 99 BS->FreePool(text); 100 } 101 102 EFI_DEVICE_PATH * 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 /* 114 * Walk device path nodes, return next instance or end node. 115 */ 116 EFI_DEVICE_PATH * 117 efi_devpath_next_instance(EFI_DEVICE_PATH *devpath) 118 { 119 while (!IsDevicePathEnd(devpath)) { 120 devpath = NextDevicePathNode(devpath); 121 if (IsDevicePathEndType(devpath) && 122 devpath->SubType == END_INSTANCE_DEVICE_PATH_SUBTYPE) { 123 devpath = NextDevicePathNode(devpath); 124 break; 125 } 126 } 127 return (devpath); 128 } 129 130 EFI_DEVICE_PATH * 131 efi_devpath_trim(EFI_DEVICE_PATH *devpath) 132 { 133 EFI_DEVICE_PATH *node, *copy; 134 size_t prefix, len; 135 136 if ((node = efi_devpath_last_node(devpath)) == NULL) 137 return (NULL); 138 prefix = (UINT8 *)node - (UINT8 *)devpath; 139 if (prefix == 0) 140 return (NULL); 141 len = prefix + DevicePathNodeLength(NextDevicePathNode(node)); 142 copy = malloc(len); 143 if (copy != NULL) { 144 memcpy(copy, devpath, prefix); 145 node = (EFI_DEVICE_PATH *)((UINT8 *)copy + prefix); 146 SetDevicePathEndNode(node); 147 } 148 return (copy); 149 } 150 151 EFI_HANDLE 152 efi_devpath_handle(EFI_DEVICE_PATH *devpath) 153 { 154 EFI_STATUS status; 155 EFI_HANDLE h; 156 157 /* 158 * There isn't a standard way to locate a handle for a given 159 * device path. However, querying the EFI_DEVICE_PATH protocol 160 * for a given device path should give us a handle for the 161 * closest node in the path to the end that is valid. 162 */ 163 status = BS->LocateDevicePath(&DevicePathGUID, &devpath, &h); 164 if (EFI_ERROR(status)) 165 return (NULL); 166 return (h); 167 } 168 169 bool 170 efi_devpath_match(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2) 171 { 172 size_t len; 173 174 if (devpath1 == NULL || devpath2 == NULL) 175 return (false); 176 177 while (true) { 178 if (DevicePathType(devpath1) != DevicePathType(devpath2) || 179 DevicePathSubType(devpath1) != DevicePathSubType(devpath2)) 180 return (false); 181 182 len = DevicePathNodeLength(devpath1); 183 if (len != DevicePathNodeLength(devpath2)) 184 return (false); 185 186 if (memcmp(devpath1, devpath2, len) != 0) 187 return (false); 188 189 if (IsDevicePathEnd(devpath1)) 190 break; 191 devpath1 = NextDevicePathNode(devpath1); 192 devpath2 = NextDevicePathNode(devpath2); 193 } 194 return (true); 195 } 196 197 bool 198 efi_devpath_is_prefix(EFI_DEVICE_PATH *prefix, EFI_DEVICE_PATH *path) 199 { 200 size_t len; 201 202 if (prefix == NULL || path == NULL) 203 return (false); 204 205 while (1) { 206 if (IsDevicePathEnd(prefix)) 207 break; 208 209 if (DevicePathType(prefix) != DevicePathType(path) || 210 DevicePathSubType(prefix) != DevicePathSubType(path)) 211 return (false); 212 213 len = DevicePathNodeLength(prefix); 214 if (len != DevicePathNodeLength(path)) 215 return (false); 216 217 if (memcmp(prefix, path, len) != 0) 218 return (false); 219 220 prefix = NextDevicePathNode(prefix); 221 path = NextDevicePathNode(path); 222 } 223 return (true); 224 } 225