xref: /freebsd/stand/efi/libefi/devpath.c (revision 6580f5c38dd5b01aeeaed16b370f1a12423437f0)
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 <efi.h>
27 #include <efilib.h>
28 #include <efichar.h>
29 #include <uuid.h>
30 #include <machine/_inttypes.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 *toTextProtocol;
37 static EFI_GUID DevicePathFromTextGUID =
38     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 = OpenProtocolByHandle(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 = OpenProtocolByHandle(handle, &DevicePathGUID,
61 	    (void **)&devpath);
62 	if (EFI_ERROR(status))
63 		devpath = NULL;
64 	return (devpath);
65 }
66 
67 void
68 efi_close_devpath(EFI_HANDLE handle)
69 {
70 	EFI_STATUS status;
71 
72 	status = BS->CloseProtocol(handle, &DevicePathGUID, IH, NULL);
73 	if (EFI_ERROR(status))
74 		printf("CloseProtocol error: %lu\n", EFI_ERROR_CODE(status));
75 }
76 
77 static char *
78 efi_make_tail(char *suffix)
79 {
80 	char *tail;
81 
82 	tail = NULL;
83 	if (suffix != NULL)
84 		(void)asprintf(&tail, "/%s", suffix);
85 	else
86 		tail = strdup("");
87 	return (tail);
88 }
89 
90 typedef struct {
91 	EFI_DEVICE_PATH	Header;
92 	EFI_GUID	Guid;
93 	UINT8		VendorDefinedData[1];
94 } __packed VENDOR_DEVICE_PATH_WITH_DATA;
95 
96 static char *
97 efi_vendor_path(const char *type, VENDOR_DEVICE_PATH *node, char *suffix)
98 {
99 	uint32_t size = DevicePathNodeLength(&node->Header) - sizeof(*node);
100 	VENDOR_DEVICE_PATH_WITH_DATA *dp = (VENDOR_DEVICE_PATH_WITH_DATA *)node;
101 	char *name, *tail, *head;
102 	char *uuid;
103 	int rv;
104 
105 	uuid_to_string((const uuid_t *)(void *)&node->Guid, &uuid, &rv);
106 	if (rv != uuid_s_ok)
107 		return (NULL);
108 
109 	tail = efi_make_tail(suffix);
110 	rv = asprintf(&head, "%sVendor(%s)[%x:", type, uuid, size);
111 	free(uuid);
112 	if (rv < 0)
113 		return (NULL);
114 
115 	if (DevicePathNodeLength(&node->Header) > sizeof(*node)) {
116 		for (uint32_t i = 0; i < size; i++) {
117 			rv = asprintf(&name, "%s%02x", head,
118 			    dp->VendorDefinedData[i]);
119 			if (rv < 0) {
120 				free(tail);
121 				free(head);
122 				return (NULL);
123 			}
124 			free(head);
125 			head = name;
126 		}
127 	}
128 
129 	if (asprintf(&name, "%s]%s", head, tail) < 0)
130 		name = NULL;
131 	free(head);
132 	free(tail);
133 	return (name);
134 }
135 
136 static char *
137 efi_hw_dev_path(EFI_DEVICE_PATH *node, char *suffix)
138 {
139 	uint8_t subtype = DevicePathSubType(node);
140 	char *name, *tail;
141 
142 	tail = efi_make_tail(suffix);
143 	switch (subtype) {
144 	case HW_PCI_DP:
145 		if (asprintf(&name, "Pci(%x,%x)%s",
146 		    ((PCI_DEVICE_PATH *)node)->Device,
147 		    ((PCI_DEVICE_PATH *)node)->Function, tail) < 0)
148 			name = NULL;
149 		break;
150 	case HW_PCCARD_DP:
151 		if (asprintf(&name, "PCCARD(%x)%s",
152 		    ((PCCARD_DEVICE_PATH *)node)->FunctionNumber, tail) < 0)
153 			name = NULL;
154 		break;
155 	case HW_MEMMAP_DP:
156 		if (asprintf(&name, "MMap(%x,%" PRIx64 ",%" PRIx64 ")%s",
157 		    ((MEMMAP_DEVICE_PATH *)node)->MemoryType,
158 		    ((MEMMAP_DEVICE_PATH *)node)->StartingAddress,
159 		    ((MEMMAP_DEVICE_PATH *)node)->EndingAddress, tail) < 0)
160 			name = NULL;
161 		break;
162 	case HW_VENDOR_DP:
163 		name = efi_vendor_path("Hardware",
164 		    (VENDOR_DEVICE_PATH *)node, tail);
165 		break;
166 	case HW_CONTROLLER_DP:
167 		if (asprintf(&name, "Ctrl(%x)%s",
168 		    ((CONTROLLER_DEVICE_PATH *)node)->Controller, tail) < 0)
169 			name = NULL;
170 		break;
171 	default:
172 		if (asprintf(&name, "UnknownHW(%x)%s", subtype, tail) < 0)
173 			name = NULL;
174 		break;
175 	}
176 	free(tail);
177 	return (name);
178 }
179 
180 static char *
181 efi_acpi_dev_path(EFI_DEVICE_PATH *node, char *suffix)
182 {
183 	uint8_t subtype = DevicePathSubType(node);
184 	ACPI_HID_DEVICE_PATH *acpi = (ACPI_HID_DEVICE_PATH *)node;
185 	char *name, *tail;
186 
187 	tail = efi_make_tail(suffix);
188 	switch (subtype) {
189 	case ACPI_DP:
190 		if ((acpi->HID & PNP_EISA_ID_MASK) == PNP_EISA_ID_CONST) {
191 			switch (EISA_ID_TO_NUM (acpi->HID)) {
192 			case 0x0a03:
193 				if (asprintf(&name, "PciRoot(%x)%s",
194 				    acpi->UID, tail) < 0)
195 					name = NULL;
196 				break;
197 			case 0x0a08:
198 				if (asprintf(&name, "PcieRoot(%x)%s",
199 				    acpi->UID, tail) < 0)
200 					name = NULL;
201 				break;
202 			case 0x0604:
203 				if (asprintf(&name, "Floppy(%x)%s",
204 				    acpi->UID, tail) < 0)
205 					name = NULL;
206 				break;
207 			case 0x0301:
208 				if (asprintf(&name, "Keyboard(%x)%s",
209 				    acpi->UID, tail) < 0)
210 					name = NULL;
211 				break;
212 			case 0x0501:
213 				if (asprintf(&name, "Serial(%x)%s",
214 				    acpi->UID, tail) < 0)
215 					name = NULL;
216 				break;
217 			case 0x0401:
218 				if (asprintf(&name, "ParallelPort(%x)%s",
219 				    acpi->UID, tail) < 0)
220 					name = NULL;
221 				break;
222 			default:
223 				if (asprintf(&name, "Acpi(PNP%04x,%x)%s",
224 				    EISA_ID_TO_NUM(acpi->HID),
225 				    acpi->UID, tail) < 0)
226 					name = NULL;
227 				break;
228 			}
229 		} else {
230 			if (asprintf(&name, "Acpi(%08x,%x)%s",
231 			    acpi->HID, acpi->UID, tail) < 0)
232 				name = NULL;
233 		}
234 		break;
235 	case ACPI_EXTENDED_DP:
236 	default:
237 		if (asprintf(&name, "UnknownACPI(%x)%s", subtype, tail) < 0)
238 			name = NULL;
239 		break;
240 	}
241 	free(tail);
242 	return (name);
243 }
244 
245 static char *
246 efi_messaging_dev_path(EFI_DEVICE_PATH *node, char *suffix)
247 {
248 	uint8_t subtype = DevicePathSubType(node);
249 	char *name;
250 	char *tail;
251 
252 	tail = efi_make_tail(suffix);
253 	switch (subtype) {
254 	case MSG_ATAPI_DP:
255 		if (asprintf(&name, "ATA(%s,%s,%x)%s",
256 		    ((ATAPI_DEVICE_PATH *)node)->PrimarySecondary == 1 ?
257 		    "Secondary" : "Primary",
258 		    ((ATAPI_DEVICE_PATH *)node)->SlaveMaster == 1 ?
259 		    "Slave" : "Master",
260 		    ((ATAPI_DEVICE_PATH *)node)->Lun, tail) < 0)
261 			name = NULL;
262 		break;
263 	case MSG_SCSI_DP:
264 		if (asprintf(&name, "SCSI(%x,%x)%s",
265 		    ((SCSI_DEVICE_PATH *)node)->Pun,
266 		    ((SCSI_DEVICE_PATH *)node)->Lun, tail) < 0)
267 			name = NULL;
268 		break;
269 	case MSG_FIBRECHANNEL_DP:
270 		if (asprintf(&name, "Fibre(%" PRIx64 ",%" PRIx64 ")%s",
271 		    ((FIBRECHANNEL_DEVICE_PATH *)node)->WWN,
272 		    ((FIBRECHANNEL_DEVICE_PATH *)node)->Lun, tail) < 0)
273 			name = NULL;
274 		break;
275 	case MSG_1394_DP:
276 		if (asprintf(&name, "I1394(%016" PRIx64 ")%s",
277 		    ((F1394_DEVICE_PATH *)node)->Guid, tail) < 0)
278 			name = NULL;
279 		break;
280 	case MSG_USB_DP:
281 		if (asprintf(&name, "USB(%x,%x)%s",
282 		    ((USB_DEVICE_PATH *)node)->ParentPortNumber,
283 		    ((USB_DEVICE_PATH *)node)->InterfaceNumber, tail) < 0)
284 			name = NULL;
285 		break;
286 	case MSG_USB_CLASS_DP:
287 		if (asprintf(&name, "UsbClass(%x,%x,%x,%x,%x)%s",
288 		    ((USB_CLASS_DEVICE_PATH *)node)->VendorId,
289 		    ((USB_CLASS_DEVICE_PATH *)node)->ProductId,
290 		    ((USB_CLASS_DEVICE_PATH *)node)->DeviceClass,
291 		    ((USB_CLASS_DEVICE_PATH *)node)->DeviceSubClass,
292 		    ((USB_CLASS_DEVICE_PATH *)node)->DeviceProtocol, tail) < 0)
293 			name = NULL;
294 		break;
295 	case MSG_MAC_ADDR_DP:
296 		if (asprintf(&name, "MAC(%02x:%02x:%02x:%02x:%02x:%02x,%x)%s",
297 		    ((MAC_ADDR_DEVICE_PATH *)node)->MacAddress.Addr[0],
298 		    ((MAC_ADDR_DEVICE_PATH *)node)->MacAddress.Addr[1],
299 		    ((MAC_ADDR_DEVICE_PATH *)node)->MacAddress.Addr[2],
300 		    ((MAC_ADDR_DEVICE_PATH *)node)->MacAddress.Addr[3],
301 		    ((MAC_ADDR_DEVICE_PATH *)node)->MacAddress.Addr[4],
302 		    ((MAC_ADDR_DEVICE_PATH *)node)->MacAddress.Addr[5],
303 		    ((MAC_ADDR_DEVICE_PATH *)node)->IfType, tail) < 0)
304 			name = NULL;
305 		break;
306 	case MSG_VENDOR_DP:
307 		name = efi_vendor_path("Messaging",
308 		    (VENDOR_DEVICE_PATH *)node, tail);
309 		break;
310 	case MSG_UART_DP:
311 		if (asprintf(&name, "UART(%" PRIu64 ",%u,%x,%x)%s",
312 		    ((UART_DEVICE_PATH *)node)->BaudRate,
313 		    ((UART_DEVICE_PATH *)node)->DataBits,
314 		    ((UART_DEVICE_PATH *)node)->Parity,
315 		    ((UART_DEVICE_PATH *)node)->StopBits, tail) < 0)
316 			name = NULL;
317 		break;
318 	case MSG_SATA_DP:
319 		if (asprintf(&name, "Sata(%x,%x,%x)%s",
320 		    ((SATA_DEVICE_PATH *)node)->HBAPortNumber,
321 		    ((SATA_DEVICE_PATH *)node)->PortMultiplierPortNumber,
322 		    ((SATA_DEVICE_PATH *)node)->Lun, tail) < 0)
323 			name = NULL;
324 		break;
325 	default:
326 		if (asprintf(&name, "UnknownMessaging(%x)%s",
327 		    subtype, tail) < 0)
328 			name = NULL;
329 		break;
330 	}
331 	free(tail);
332 	return (name);
333 }
334 
335 static char *
336 efi_media_dev_path(EFI_DEVICE_PATH *node, char *suffix)
337 {
338 	uint8_t subtype = DevicePathSubType(node);
339 	HARDDRIVE_DEVICE_PATH *hd;
340 	char *name;
341 	char *str;
342 	char *tail;
343 	int rv;
344 
345 	tail = efi_make_tail(suffix);
346 	name = NULL;
347 	switch (subtype) {
348 	case MEDIA_HARDDRIVE_DP:
349 		hd = (HARDDRIVE_DEVICE_PATH *)node;
350 		switch (hd->SignatureType) {
351 		case SIGNATURE_TYPE_MBR:
352 			if (asprintf(&name, "HD(%d,MBR,%08x,%" PRIx64
353 			    ",%" PRIx64 ")%s",
354 			    hd->PartitionNumber,
355 			    *((uint32_t *)(uintptr_t)&hd->Signature[0]),
356 			    hd->PartitionStart,
357 			    hd->PartitionSize, tail) < 0)
358 				name = NULL;
359 			break;
360 		case SIGNATURE_TYPE_GUID:
361 			name = NULL;
362 			uuid_to_string((const uuid_t *)(void *)
363 			    &hd->Signature[0], &str, &rv);
364 			if (rv != uuid_s_ok)
365 				break;
366 			rv = asprintf(&name, "HD(%d,GPT,%s,%" PRIx64 ",%"
367 			    PRIx64 ")%s",
368 			    hd->PartitionNumber, str,
369 			    hd->PartitionStart, hd->PartitionSize, tail);
370 			free(str);
371 			break;
372 		default:
373 			if (asprintf(&name, "HD(%d,%d,0)%s",
374 			    hd->PartitionNumber,
375 			    hd->SignatureType, tail) < 0) {
376 				name = NULL;
377 			}
378 			break;
379 		}
380 		break;
381 	case MEDIA_CDROM_DP:
382 		if (asprintf(&name, "CD(%x,%" PRIx64 ",%" PRIx64 ")%s",
383 		    ((CDROM_DEVICE_PATH *)node)->BootEntry,
384 		    ((CDROM_DEVICE_PATH *)node)->PartitionStart,
385 		    ((CDROM_DEVICE_PATH *)node)->PartitionSize, tail) < 0) {
386 			name = NULL;
387 		}
388 		break;
389 	case MEDIA_VENDOR_DP:
390 		name = efi_vendor_path("Media",
391 		    (VENDOR_DEVICE_PATH *)node, tail);
392 		break;
393 	case MEDIA_FILEPATH_DP:
394 		name = NULL;
395 		str = NULL;
396 		if (ucs2_to_utf8(((FILEPATH_DEVICE_PATH *)node)->PathName,
397 		    &str) == 0) {
398 			(void)asprintf(&name, "%s%s", str, tail);
399 			free(str);
400 		}
401 		break;
402 	case MEDIA_PROTOCOL_DP:
403 		name = NULL;
404 		uuid_to_string((const uuid_t *)(void *)
405 		    &((MEDIA_PROTOCOL_DEVICE_PATH *)node)->Protocol,
406 		    &str, &rv);
407 		if (rv != uuid_s_ok)
408 			break;
409 		rv = asprintf(&name, "Protocol(%s)%s", str, tail);
410 		free(str);
411 		break;
412 	default:
413 		if (asprintf(&name, "UnknownMedia(%x)%s",
414 		    subtype, tail) < 0)
415 			name = NULL;
416 	}
417 	free(tail);
418 	return (name);
419 }
420 
421 static char *
422 efi_translate_devpath(EFI_DEVICE_PATH *devpath)
423 {
424 	EFI_DEVICE_PATH *dp = NextDevicePathNode(devpath);
425 	char *name, *ptr;
426 	uint8_t type;
427 
428 	if (!IsDevicePathEnd(devpath))
429 		name = efi_translate_devpath(dp);
430 	else
431 		return (NULL);
432 
433 	ptr = NULL;
434 	type = DevicePathType(devpath);
435 	switch (type) {
436 	case HARDWARE_DEVICE_PATH:
437 		ptr = efi_hw_dev_path(devpath, name);
438 		break;
439 	case ACPI_DEVICE_PATH:
440 		ptr = efi_acpi_dev_path(devpath, name);
441 		break;
442 	case MESSAGING_DEVICE_PATH:
443 		ptr = efi_messaging_dev_path(devpath, name);
444 		break;
445 	case MEDIA_DEVICE_PATH:
446 		ptr = efi_media_dev_path(devpath, name);
447 		break;
448 	case BBS_DEVICE_PATH:
449 	default:
450 		if (asprintf(&ptr, "UnknownPath(%x)%s", type,
451 		    name? name : "") < 0)
452 			ptr = NULL;
453 		break;
454 	}
455 
456 	if (ptr != NULL) {
457 		free(name);
458 		name = ptr;
459 	}
460 	return (name);
461 }
462 
463 static CHAR16 *
464 efi_devpath_to_name(EFI_DEVICE_PATH *devpath)
465 {
466 	char *name = NULL;
467 	CHAR16 *ptr = NULL;
468 	size_t len;
469 	int rv;
470 
471 	name = efi_translate_devpath(devpath);
472 	if (name == NULL)
473 		return (NULL);
474 
475 	/*
476 	 * We need to return memory from AllocatePool, so it can be freed
477 	 * with FreePool() in efi_free_devpath_name().
478 	 */
479 	rv = utf8_to_ucs2(name, &ptr, &len);
480 	free(name);
481 	if (rv == 0) {
482 		CHAR16 *out = NULL;
483 		EFI_STATUS status;
484 
485 		status = BS->AllocatePool(EfiLoaderData, len, (void **)&out);
486 		if (EFI_ERROR(status)) {
487 			free(ptr);
488                 	return (out);
489 		}
490 		memcpy(out, ptr, len);
491 		free(ptr);
492 		ptr = out;
493 	}
494 
495 	return (ptr);
496 }
497 
498 CHAR16 *
499 efi_devpath_name(EFI_DEVICE_PATH *devpath)
500 {
501 	EFI_STATUS status;
502 
503 	if (devpath == NULL)
504 		return (NULL);
505 	if (toTextProtocol == NULL) {
506 		status = BS->LocateProtocol(&DevicePathToTextGUID, NULL,
507 		    (VOID **)&toTextProtocol);
508 		if (EFI_ERROR(status))
509 			toTextProtocol = NULL;
510 	}
511 	if (toTextProtocol == NULL)
512 		return (efi_devpath_to_name(devpath));
513 
514 	return (toTextProtocol->ConvertDevicePathToText(devpath, TRUE, TRUE));
515 }
516 
517 void
518 efi_free_devpath_name(CHAR16 *text)
519 {
520 	if (text != NULL)
521 		BS->FreePool(text);
522 }
523 
524 EFI_DEVICE_PATH *
525 efi_name_to_devpath(const char *path)
526 {
527 	EFI_DEVICE_PATH *devpath;
528 	CHAR16 *uv;
529 	size_t ul;
530 
531 	uv = NULL;
532 	if (utf8_to_ucs2(path, &uv, &ul) != 0)
533 		return (NULL);
534 	devpath = efi_name_to_devpath16(uv);
535 	free(uv);
536 	return (devpath);
537 }
538 
539 EFI_DEVICE_PATH *
540 efi_name_to_devpath16(CHAR16 *path)
541 {
542 	EFI_STATUS status;
543 
544 	if (path == NULL)
545 		return (NULL);
546 	if (fromTextProtocol == NULL) {
547 		status = BS->LocateProtocol(&DevicePathFromTextGUID, NULL,
548 		    (VOID **)&fromTextProtocol);
549 		if (EFI_ERROR(status))
550 			fromTextProtocol = NULL;
551 	}
552 	if (fromTextProtocol == NULL)
553 		return (NULL);
554 
555 	return (fromTextProtocol->ConvertTextToDevicePath(path));
556 }
557 
558 void efi_devpath_free(EFI_DEVICE_PATH *devpath)
559 {
560 
561 	BS->FreePool(devpath);
562 }
563 
564 EFI_DEVICE_PATH *
565 efi_devpath_last_node(EFI_DEVICE_PATH *devpath)
566 {
567 
568 	if (IsDevicePathEnd(devpath))
569 		return (NULL);
570 	while (!IsDevicePathEnd(NextDevicePathNode(devpath)))
571 		devpath = NextDevicePathNode(devpath);
572 	return (devpath);
573 }
574 
575 /*
576  * Walk device path nodes, return next instance or end node.
577  */
578 EFI_DEVICE_PATH *
579 efi_devpath_next_instance(EFI_DEVICE_PATH *devpath)
580 {
581 	while (!IsDevicePathEnd(devpath)) {
582 		devpath = NextDevicePathNode(devpath);
583 		if (IsDevicePathEndType(devpath) &&
584 		    devpath->SubType == END_INSTANCE_DEVICE_PATH_SUBTYPE) {
585 			devpath = NextDevicePathNode(devpath);
586 			break;
587 		}
588 	}
589 	return (devpath);
590 }
591 
592 EFI_DEVICE_PATH *
593 efi_devpath_trim(EFI_DEVICE_PATH *devpath)
594 {
595 	EFI_DEVICE_PATH *node, *copy;
596 	size_t prefix, len;
597 
598 	if ((node = efi_devpath_last_node(devpath)) == NULL)
599 		return (NULL);
600 	prefix = (UINT8 *)node - (UINT8 *)devpath;
601 	if (prefix == 0)
602 		return (NULL);
603 	len = prefix + DevicePathNodeLength(NextDevicePathNode(node));
604 	copy = malloc(len);
605 	if (copy != NULL) {
606 		memcpy(copy, devpath, prefix);
607 		node = (EFI_DEVICE_PATH *)((UINT8 *)copy + prefix);
608 		SetDevicePathEndNode(node);
609 	}
610 	return (copy);
611 }
612 
613 EFI_HANDLE
614 efi_devpath_handle(EFI_DEVICE_PATH *devpath)
615 {
616 	EFI_STATUS status;
617 	EFI_HANDLE h;
618 
619 	/*
620 	 * There isn't a standard way to locate a handle for a given
621 	 * device path.  However, querying the EFI_DEVICE_PATH protocol
622 	 * for a given device path should give us a handle for the
623 	 * closest node in the path to the end that is valid.
624 	 */
625 	status = BS->LocateDevicePath(&DevicePathGUID, &devpath, &h);
626 	if (EFI_ERROR(status))
627 		return (NULL);
628 	return (h);
629 }
630 
631 bool
632 efi_devpath_match_node(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2)
633 {
634 	size_t len;
635 
636 	if (devpath1 == NULL || devpath2 == NULL)
637 		return (false);
638 	if (DevicePathType(devpath1) != DevicePathType(devpath2) ||
639 	    DevicePathSubType(devpath1) != DevicePathSubType(devpath2))
640 		return (false);
641 	len = DevicePathNodeLength(devpath1);
642 	if (len != DevicePathNodeLength(devpath2))
643 		return (false);
644 	if (memcmp(devpath1, devpath2, len) != 0)
645 		return (false);
646 	return (true);
647 }
648 
649 static bool
650 _efi_devpath_match(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2,
651     bool ignore_media)
652 {
653 
654 	if (devpath1 == NULL || devpath2 == NULL)
655 		return (false);
656 
657 	while (true) {
658 		if (ignore_media &&
659 		    IsDevicePathType(devpath1, MEDIA_DEVICE_PATH) &&
660 		    IsDevicePathType(devpath2, MEDIA_DEVICE_PATH))
661 			return (true);
662 		if (!efi_devpath_match_node(devpath1, devpath2))
663 			return false;
664 		if (IsDevicePathEnd(devpath1))
665 			break;
666 		devpath1 = NextDevicePathNode(devpath1);
667 		devpath2 = NextDevicePathNode(devpath2);
668 	}
669 	return (true);
670 }
671 /*
672  * Are two devpaths identical?
673  */
674 bool
675 efi_devpath_match(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2)
676 {
677 	return _efi_devpath_match(devpath1, devpath2, false);
678 }
679 
680 /*
681  * Like efi_devpath_match, but stops at when we hit the media device
682  * path node that specifies the partition information. If we match
683  * up to that point, then we're on the same disk.
684  */
685 bool
686 efi_devpath_same_disk(EFI_DEVICE_PATH *devpath1, EFI_DEVICE_PATH *devpath2)
687 {
688 	return _efi_devpath_match(devpath1, devpath2, true);
689 }
690 
691 bool
692 efi_devpath_is_prefix(EFI_DEVICE_PATH *prefix, EFI_DEVICE_PATH *path)
693 {
694 	size_t len;
695 
696 	if (prefix == NULL || path == NULL)
697 		return (false);
698 
699 	while (1) {
700 		if (IsDevicePathEnd(prefix))
701 			break;
702 
703 		if (DevicePathType(prefix) != DevicePathType(path) ||
704 		    DevicePathSubType(prefix) != DevicePathSubType(path))
705 			return (false);
706 
707 		len = DevicePathNodeLength(prefix);
708 		if (len != DevicePathNodeLength(path))
709 			return (false);
710 
711 		if (memcmp(prefix, path, len) != 0)
712 			return (false);
713 
714 		prefix = NextDevicePathNode(prefix);
715 		path = NextDevicePathNode(path);
716 	}
717 	return (true);
718 }
719 
720 /*
721  * Skip over the 'prefix' part of path and return the part of the path
722  * that starts with the first node that's a MEDIA_DEVICE_PATH.
723  */
724 EFI_DEVICE_PATH *
725 efi_devpath_to_media_path(EFI_DEVICE_PATH *path)
726 {
727 
728 	while (!IsDevicePathEnd(path)) {
729 		if (DevicePathType(path) == MEDIA_DEVICE_PATH)
730 			return (path);
731 		path = NextDevicePathNode(path);
732 	}
733 	return (NULL);
734 }
735 
736 UINTN
737 efi_devpath_length(EFI_DEVICE_PATH  *path)
738 {
739 	EFI_DEVICE_PATH *start = path;
740 
741 	while (!IsDevicePathEnd(path))
742 		path = NextDevicePathNode(path);
743 	return ((UINTN)path - (UINTN)start) + DevicePathNodeLength(path);
744 }
745 
746 EFI_HANDLE
747 efi_devpath_to_handle(EFI_DEVICE_PATH *path, EFI_HANDLE *handles, unsigned nhandles)
748 {
749 	unsigned i;
750 	EFI_DEVICE_PATH *media, *devpath;
751 	EFI_HANDLE h;
752 
753 	media = efi_devpath_to_media_path(path);
754 	if (media == NULL)
755 		return (NULL);
756 	for (i = 0; i < nhandles; i++) {
757 		h = handles[i];
758 		devpath = efi_lookup_devpath(h);
759 		if (devpath == NULL)
760 			continue;
761 		if (!efi_devpath_match_node(media, efi_devpath_to_media_path(devpath)))
762 			continue;
763 		return (h);
764 	}
765 	return (NULL);
766 }
767