stand/efi/libefi/devpath.c

   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 #include <efichar.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 *toTextProtocol;
  38 static EFI_GUID DevicePathFromTextGUID = EFI_DEVICE_PATH_FROM_TEXT_PROTOCOL_GUID;
  39 static EFI_DEVICE_PATH_FROM_TEXT_PROTOCOL *fromTextProtocol;
  40
  41 EFI_DEVICE_PATH *
  42 efi_lookup_image_devpath(EFI_HANDLE handle)
  43 {
  44         EFI_DEVICE_PATH *devpath;
  45         EFI_STATUS status;
  46
  47         status = BS->HandleProtocol(handle, &ImageDevicePathGUID,
  48             (VOID **)&devpath);
  49         if (EFI_ERROR(status))
  50                 devpath = NULL;
  51         return (devpath);
  52 }
  53
  54 EFI_DEVICE_PATH *
  55 efi_lookup_devpath(EFI_HANDLE handle)
  56 {
  57         EFI_DEVICE_PATH *devpath;
  58         EFI_STATUS status;
  59
  60         status = BS->HandleProtocol(handle, &DevicePathGUID, (VOID **)&devpath);
  61         if (EFI_ERROR(status))
  62                 devpath = NULL;
  63         return (devpath);
  64 }
  65
  66 CHAR16 *
  67 efi_devpath_name(EFI_DEVICE_PATH *devpath)
  68 {
  69         EFI_STATUS status;
  70
  71         if (devpath == NULL)
  72                 return (NULL);
  73         if (toTextProtocol == NULL) {
  74                 status = BS->LocateProtocol(&DevicePathToTextGUID, NULL,
  75                     (VOID **)&toTextProtocol);
  76                 if (EFI_ERROR(status))
  77                         toTextProtocol = NULL;
  78         }
  79         if (toTextProtocol == NULL)
  80                 return (NULL);
  81
  82         return (toTextProtocol->ConvertDevicePathToText(devpath, TRUE, TRUE));
  83 }
  84
  85 void
  86 efi_free_devpath_name(CHAR16 *text)
  87 {
  88
  89         BS->FreePool(text);
  90 }
  91
  92 EFI_DEVICE_PATH *
  93 efi_name_to_devpath(const char *path)
  94 {
  95         EFI_DEVICE_PATH *devpath;
  96         CHAR16 *uv;
  97         size_t ul;
  98
  99         uv = NULL;
 100         if (utf8_to_ucs2(path, &uv, &ul) != 0)
 101                 return (NULL);
 102         devpath = efi_name_to_devpath16(uv);
 103         free(uv);
 104         return (devpath);
 105 }
 106
 107 EFI_DEVICE_PATH *
 108 efi_name_to_devpath16(CHAR16 *path)
 109 {
 110         EFI_STATUS status;
 111
 112         if (path == NULL)
 113                 return (NULL);
 114         if (fromTextProtocol == NULL) {
 115                 status = BS->LocateProtocol(&DevicePathFromTextGUID, NULL,
 116                     (VOID **)&fromTextProtocol);
 117                 if (EFI_ERROR(status))
 118                         fromTextProtocol = NULL;
 119         }
 120         if (fromTextProtocol == NULL)
 121                 return (NULL);
 122
 123         return (fromTextProtocol->ConvertTextToDevicePath(path));
 124 }
 125
 126 void efi_devpath_free(EFI_DEVICE_PATH *devpath)
 127 {
 128
 129         BS->FreePool(devpath);
 130 }
 131
 132 EFI_DEVICE_PATH *
 133 efi_devpath_last_node(EFI_DEVICE_PATH *devpath)
 134 {
 135
 136         if (IsDevicePathEnd(devpath))
 137                 return (NULL);
 138         while (!IsDevicePathEnd(NextDevicePathNode(devpath)))
 139                 devpath = NextDevicePathNode(devpath);
 140         return (devpath);
 141 }
 142
 143 EFI_DEVICE_PATH *
 144 efi_devpath_trim(EFI_DEVICE_PATH *devpath)
 145 {
 146         EFI_DEVICE_PATH *node, *copy;
 147         size_t prefix, len;
 148
 149         if ((node = efi_devpath_last_node(devpath)) == NULL)
 150                 return (NULL);
 151         prefix = (UINT8 *)node - (UINT8 *)devpath;
 152         if (prefix == 0)
 153                 return (NULL);
 154         len = prefix + DevicePathNodeLength(NextDevicePathNode(node));
 155         copy = malloc(len);
 156         if (copy != NULL) {
 157                 memcpy(copy, devpath, prefix);
 158                 node = (EFI_DEVICE_PATH *)((UINT8 *)copy + prefix);
 159                 SetDevicePathEndNode(node);
 160         }
 161         return (copy);
 162 }
 163
 164 EFI_HANDLE
 165 efi_devpath_handle(EFI_DEVICE_PATH *devpath)
 166 {
 167         EFI_STATUS status;
 168         EFI_HANDLE h;
 169
 170         /*
 171          * There isn't a standard way to locate a handle for a given
 172          * device path.  However, querying the EFI_DEVICE_PATH protocol
 173          * for a given device path should give us a handle for the
 174          * closest node in the path to the end that is valid.
 175          */
 176         status = BS->LocateDevicePath(&DevicePathGUID, &devpath, &h);
 177         if (EFI_ERROR(status))
 178                 return (NULL);
 179         return (h);
 180 }
 181
 182 bool
 183 efi_devpath_match_node(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2)
 184 {
 185         size_t len;
 186
 187         if (devpath1 == NULL || devpath2 == NULL)
 188                 return (false);
 189         if (DevicePathType(devpath1) != DevicePathType(devpath2) ||
 190             DevicePathSubType(devpath1) != DevicePathSubType(devpath2))
 191                 return (false);
 192         len = DevicePathNodeLength(devpath1);
 193         if (len != DevicePathNodeLength(devpath2))
 194                 return (false);
 195         if (memcmp(devpath1, devpath2, len) != 0)
 196                 return (false);
 197         return (true);
 198 }
 199
 200 static bool
 201 _efi_devpath_match(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2,
 202     bool ignore_media)
 203 {
 204
 205         if (devpath1 == NULL || devpath2 == NULL)
 206                 return (false);
 207
 208         while (true) {
 209                 if (ignore_media &&
 210                     IsDevicePathType(devpath1, MEDIA_DEVICE_PATH) &&
 211                     IsDevicePathType(devpath2, MEDIA_DEVICE_PATH))
 212                         return (true);
 213                 if (!efi_devpath_match_node(devpath1, devpath2))
 214                         return false;
 215                 if (IsDevicePathEnd(devpath1))
 216                         break;
 217                 devpath1 = NextDevicePathNode(devpath1);
 218                 devpath2 = NextDevicePathNode(devpath2);
 219         }
 220         return (true);
 221 }
 222 /*
 223  * Are two devpaths identical?
 224  */
 225 bool
 226 efi_devpath_match(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2)
 227 {
 228         return _efi_devpath_match(devpath1, devpath2, false);
 229 }
 230
 231 /*
 232  * Like efi_devpath_match, but stops at when we hit the media device
 233  * path node that specifies the partition information. If we match
 234  * up to that point, then we're on the same disk.
 235  */
 236 bool
 237 efi_devpath_same_disk(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2)
 238 {
 239         return _efi_devpath_match(devpath1, devpath2, true);
 240 }
 241
 242 bool
 243 efi_devpath_is_prefix(EFI_DEVICE_PATH *prefix, EFI_DEVICE_PATH *path)
 244 {
 245         size_t len;
 246
 247         if (prefix == NULL || path == NULL)
 248                 return (false);
 249
 250         while (1) {
 251                 if (IsDevicePathEnd(prefix))
 252                         break;
 253
 254                 if (DevicePathType(prefix) != DevicePathType(path) ||
 255                     DevicePathSubType(prefix) != DevicePathSubType(path))
 256                         return (false);
 257
 258                 len = DevicePathNodeLength(prefix);
 259                 if (len != DevicePathNodeLength(path))
 260                         return (false);
 261
 262                 if (memcmp(prefix, path, len) != 0)
 263                         return (false);
 264
 265                 prefix = NextDevicePathNode(prefix);
 266                 path = NextDevicePathNode(path);
 267         }
 268         return (true);
 269 }
 270
 271 /*
 272  * Skip over the 'prefix' part of path and return the part of the path
 273  * that starts with the first node that's a MEDIA_DEVICE_PATH.
 274  */
 275 EFI_DEVICE_PATH *
 276 efi_devpath_to_media_path(EFI_DEVICE_PATH *path)
 277 {
 278
 279         while (!IsDevicePathEnd(path)) {
 280                 if (DevicePathType(path) == MEDIA_DEVICE_PATH)
 281                         return (path);
 282                 path = NextDevicePathNode(path);
 283         }
 284         return (NULL);
 285 }
 286
 287 UINTN
 288 efi_devpath_length(EFI_DEVICE_PATH  *path)
 289 {
 290         EFI_DEVICE_PATH *start = path;
 291
 292         while (!IsDevicePathEnd(path))
 293                 path = NextDevicePathNode(path);
 294         return ((UINTN)path - (UINTN)start) + DevicePathNodeLength(path);
 295 }
 296
 297 EFI_HANDLE
 298 efi_devpath_to_handle(EFI_DEVICE_PATH *path, EFI_HANDLE *handles, unsigned nhandles)
 299 {
 300         unsigned i;
 301         EFI_DEVICE_PATH *media, *devpath;
 302         EFI_HANDLE h;
 303
 304         media = efi_devpath_to_media_path(path);
 305         if (media == NULL)
 306                 return (NULL);
 307         for (i = 0; i < nhandles; i++) {
 308                 h = handles[i];
 309                 devpath = efi_lookup_devpath(h);
 310                 if (devpath == NULL)
 311                         continue;
 312                 if (!efi_devpath_match_node(media, efi_devpath_to_media_path(devpath)))
 313                         continue;
 314                 return (h);
 315         }
 316         return (NULL);
 317 }