xref: /freebsd/lib/libefivar/efivar-dp-xlate.c (revision 7ef62cebc2f965b0f640263e179276928885e33d)
1 /*-
2  * Copyright (c) 2017 Netflix, Inc.
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 <sys/param.h>
30 #include <sys/ucred.h>
31 #include <sys/mount.h>
32 
33 #undef MAX
34 #undef MIN
35 
36 #include <assert.h>
37 #include <efivar.h>
38 #include <errno.h>
39 #include <libgeom.h>
40 #include <paths.h>
41 #include <stdio.h>
42 #include <string.h>
43 
44 #include "efichar.h"
45 
46 #include "efi-osdep.h"
47 #include "efivar-dp.h"
48 
49 #include "uefi-dplib.h"
50 
51 #define MAX_DP_SANITY	4096		/* Biggest device path in bytes */
52 #define MAX_DP_TEXT_LEN	4096		/* Longest string rep of dp */
53 
54 #define ValidLen(dp) (DevicePathNodeLength(dp) >= sizeof(EFI_DEVICE_PATH_PROTOCOL) && \
55 	    DevicePathNodeLength(dp) < MAX_DP_SANITY)
56 
57 #define	G_PART	"PART"
58 #define	G_LABEL "LABEL"
59 #define G_DISK	"DISK"
60 
61 static const char *
62 geom_pp_attr(struct gmesh *mesh, struct gprovider *pp, const char *attr)
63 {
64 	struct gconfig *conf;
65 
66 	LIST_FOREACH(conf, &pp->lg_config, lg_config) {
67 		if (strcmp(conf->lg_name, attr) != 0)
68 			continue;
69 		return (conf->lg_val);
70 	}
71 	return (NULL);
72 }
73 
74 static struct gprovider *
75 find_provider_by_efimedia(struct gmesh *mesh, const char *efimedia)
76 {
77 	struct gclass *classp;
78 	struct ggeom *gp;
79 	struct gprovider *pp;
80 	const char *val;
81 
82 	/*
83 	 * Find the partition class so we can search it...
84 	 */
85 	LIST_FOREACH(classp, &mesh->lg_class, lg_class) {
86 		if (strcasecmp(classp->lg_name, G_PART) == 0)
87 			break;
88 	}
89 	if (classp == NULL)
90 		return (NULL);
91 
92 	/*
93 	 * Each geom will have a number of providers, search each
94 	 * one of them for the efimedia that matches.
95 	 */
96 	/* XXX just used gpart class since I know it's the only one, but maybe I should search all classes */
97 	LIST_FOREACH(gp, &classp->lg_geom, lg_geom) {
98 		LIST_FOREACH(pp, &gp->lg_provider, lg_provider) {
99 			val = geom_pp_attr(mesh, pp, "efimedia");
100 			if (val == NULL)
101 				continue;
102 			if (strcasecmp(efimedia, val) == 0)
103 				return (pp);
104 		}
105 	}
106 
107 	return (NULL);
108 }
109 
110 static struct gprovider *
111 find_provider_by_name(struct gmesh *mesh, const char *name)
112 {
113 	struct gclass *classp;
114 	struct ggeom *gp;
115 	struct gprovider *pp;
116 
117 	LIST_FOREACH(classp, &mesh->lg_class, lg_class) {
118 		LIST_FOREACH(gp, &classp->lg_geom, lg_geom) {
119 			LIST_FOREACH(pp, &gp->lg_provider, lg_provider) {
120 				if (strcmp(pp->lg_name, name) == 0)
121 					return (pp);
122 			}
123 		}
124 	}
125 
126 	return (NULL);
127 }
128 
129 
130 static int
131 efi_hd_to_unix(struct gmesh *mesh, const_efidp dp, char **dev, char **relpath, char **abspath)
132 {
133 	int rv = 0, n, i;
134 	const_efidp media, file, walker;
135 	size_t len, mntlen;
136 	char buf[MAX_DP_TEXT_LEN];
137 	char *pwalk, *newdev = NULL;
138 	struct gprovider *pp, *provider;
139 	struct statfs *mnt;
140 	struct gclass *glabel;
141 	struct ggeom *gp;
142 
143 	walker = media = dp;
144 	*dev = NULL;
145 	*relpath = NULL;
146 
147 	/*
148 	 * Now, we can either have a filepath node next, or the end.
149 	 * Otherwise, it's an error.
150 	 */
151 	if (!ValidLen(walker))
152 		return (EINVAL);
153 	walker = (const_efidp)NextDevicePathNode(walker);
154 	if ((uintptr_t)walker - (uintptr_t)dp > MAX_DP_SANITY)
155 		return (EINVAL);
156 	if (DevicePathType(walker) ==  MEDIA_DEVICE_PATH &&
157 	    DevicePathSubType(walker) == MEDIA_FILEPATH_DP)
158 		file = walker;
159 	else if (DevicePathType(walker) == MEDIA_DEVICE_PATH &&
160 	    DevicePathType(walker) == END_DEVICE_PATH_TYPE)
161 		file = NULL;
162 	else
163 		return (EINVAL);
164 
165 	/*
166 	 * Format this node. We're going to look for it as a efimedia
167 	 * attribute of some geom node. Once we find that node, we use it
168 	 * as the device it comes from, at least provisionally.
169 	 */
170 	len = efidp_format_device_path_node(buf, sizeof(buf), media);
171 	if (len > sizeof(buf))
172 		return (EINVAL);
173 
174 	pp = find_provider_by_efimedia(mesh, buf);
175 	if (pp == NULL) {
176 		rv = ENOENT;
177 		goto errout;
178 	}
179 
180 	/*
181 	 * No file specified, just return the device. Don't even look
182 	 * for a mountpoint. XXX Sane?
183 	 */
184 	if (file == NULL)
185 		goto errout;
186 
187 	/*
188 	 * Now extract the relative path. The next node in the device path should
189 	 * be a filesystem node. If not, we have issues.
190 	 */
191 	*relpath = efidp_extract_file_path(file);
192 	if (*relpath == NULL) {
193 		rv = ENOMEM;
194 		goto errout;
195 	}
196 	for (pwalk = *relpath; *pwalk; pwalk++)
197 		if (*pwalk == '\\')
198 			*pwalk = '/';
199 
200 	/*
201 	 * To find the absolute path, we have to look for where we're mounted.
202 	 * We only look a little hard, since looking too hard can come up with
203 	 * false positives (imagine a graid, one of whose devices is *dev).
204 	 */
205 	n = getfsstat(NULL, 0, MNT_NOWAIT) + 1;
206 	if (n < 0) {
207 		rv = errno;
208 		goto errout;
209 	}
210 	mntlen = sizeof(struct statfs) * n;
211 	mnt = malloc(mntlen);
212 	n = getfsstat(mnt, mntlen, MNT_NOWAIT);
213 	if (n < 0) {
214 		rv = errno;
215 		goto errout;
216 	}
217 
218 	/*
219 	 * Find glabel, if it exists. It's OK if not: we'll skip searching for
220 	 * labels.
221 	 */
222 	LIST_FOREACH(glabel, &mesh->lg_class, lg_class) {
223 		if (strcmp(glabel->lg_name, G_LABEL) == 0)
224 			break;
225 	}
226 
227 	provider = pp;
228 	for (i = 0; i < n; i++) {
229 		/*
230 		 * Skip all pseudo filesystems. This also skips the real filesytsem
231 		 * of ZFS. There's no EFI designator for ZFS in the standard, so
232 		 * we'll need to invent one, but its decoding will be handled in
233 		 * a separate function.
234 		 */
235 		if (strncmp(mnt[i].f_mntfromname, "/dev/", 5) != 0)
236 			continue;
237 
238 		/*
239 		 * First see if it is directly attached
240 		 */
241 		if (strcmp(provider->lg_name, mnt[i].f_mntfromname + 5) == 0) {
242 			newdev = provider->lg_name;
243 			break;
244 		}
245 
246 		/*
247 		 * Next see if it is attached via one of the physical disk's labels.
248 		 * We can't search directly from the pointers we have for the
249 		 * provider, so we have to cast a wider net for all labels and
250 		 * filter those down to geoms whose name matches the PART provider
251 		 * we found the efimedia attribute on.
252 		 */
253 		if (glabel == NULL)
254 			continue;
255 		LIST_FOREACH(gp, &glabel->lg_geom, lg_geom) {
256 			if (strcmp(gp->lg_name, provider->lg_name) != 0) {
257 				continue;
258 			}
259 			LIST_FOREACH(pp, &gp->lg_provider, lg_provider) {
260 				if (strcmp(pp->lg_name, mnt[i].f_mntfromname + 5) == 0) {
261 					newdev = pp->lg_name;
262 					goto break2;
263 				}
264 			}
265 		}
266 		/* Not the one, try the next mount point */
267 	}
268 break2:
269 
270 	/*
271 	 * If nothing better was mounted, then use the provider we found as
272 	 * is. It's the most correct thing we can return in that acse.
273 	 */
274 	if (newdev == NULL)
275 		newdev = provider->lg_name;
276 	*dev = strdup(newdev);
277 	if (*dev == NULL) {
278 		rv = ENOMEM;
279 		goto errout;
280 	}
281 
282 	/*
283 	 * No mountpoint found, no absolute path possible
284 	 */
285 	if (i >= n)
286 		goto errout;
287 
288 	/*
289 	 * Construct absolute path and we're finally done.
290 	 */
291 	if (strcmp(mnt[i].f_mntonname, "/") == 0)
292 		asprintf(abspath, "/%s", *relpath);
293 	else
294 		asprintf(abspath, "%s/%s", mnt[i].f_mntonname, *relpath);
295 
296 errout:
297 	if (rv != 0) {
298 		free(*dev);
299 		*dev = NULL;
300 		free(*relpath);
301 		*relpath = NULL;
302 	}
303 	return (rv);
304 }
305 
306 /*
307  * Translate the passed in device_path to a unix path via the following
308  * algorithm.
309  *
310  * If dp, dev or path NULL, return EDOOFUS. XXX wise?
311  *
312  * Set *path = NULL; *dev = NULL;
313  *
314  * Walk through the device_path until we find either a media device path.
315  * Return EINVAL if not found. Return EINVAL if walking dp would
316  * land us more than sanity size away from the start (4k).
317  *
318  * If we find a media descriptor, we search through the geom mesh to see if we
319  * can find a matching node. If no match is found in the mesh that matches,
320  * return ENXIO.
321  *
322  * Once we find a matching node, we search to see if there is a filesystem
323  * mounted on it. If we find nothing, then search each of the devices that are
324  * mounted to see if we can work up the geom tree to find the matching node. if
325  * we still can't find anything, *dev = sprintf("/dev/%s", provider_name
326  * of the original node we found), but return ENOTBLK.
327  *
328  * Record the dev of the mountpoint in *dev.
329  *
330  * Once we find something, check to see if the next node in the device path is
331  * the end of list. If so, return the mountpoint.
332  *
333  * If the next node isn't a File path node, return EFTYPE.
334  *
335  * Extract the path from the File path node(s). translate any \ file separators
336  * to /. Append the result to the mount point. Copy the resulting path into
337  * *path.  Stat that path. If it is not found, return the errorr from stat.
338  *
339  * Finally, check to make sure the resulting path is still on the same
340  * device. If not, return ENODEV.
341  *
342  * Otherwise return 0.
343  *
344  * The dev or full path that's returned is malloced, so needs to be freed when
345  * the caller is done about it. Unlike many other functions, we can return data
346  * with an error code, so pay attention.
347  */
348 int
349 efivar_device_path_to_unix_path(const_efidp dp, char **dev, char **relpath, char **abspath)
350 {
351 	const_efidp walker;
352 	struct gmesh mesh;
353 	int rv = 0;
354 
355 	/*
356 	 * Sanity check args, fail early
357 	 */
358 	if (dp == NULL || dev == NULL || relpath == NULL || abspath == NULL)
359 		return (EDOOFUS);
360 
361 	*dev = NULL;
362 	*relpath = NULL;
363 	*abspath = NULL;
364 
365 	/*
366 	 * Find the first media device path we can. If we go too far,
367 	 * assume the passed in device path is bogus. If we hit the end
368 	 * then we didn't find a media device path, so signal that error.
369 	 */
370 	walker = dp;
371 	if (!ValidLen(walker))
372 		return (EINVAL);
373 	while (DevicePathType(walker) != MEDIA_DEVICE_PATH &&
374 	    DevicePathType(walker) != END_DEVICE_PATH_TYPE) {
375 		walker = (const_efidp)NextDevicePathNode(walker);
376 		if ((uintptr_t)walker - (uintptr_t)dp > MAX_DP_SANITY)
377 			return (EINVAL);
378 		if (!ValidLen(walker))
379 			return (EINVAL);
380 	}
381 	if (DevicePathType(walker) !=  MEDIA_DEVICE_PATH)
382 		return (EINVAL);
383 
384 	/*
385 	 * There's several types of media paths. We're only interested in the
386 	 * hard disk path, as it's really the only relevant one to booting. The
387 	 * CD path just might also be relevant, and would be easy to add, but
388 	 * isn't supported. A file path too is relevant, but at this stage, it's
389 	 * premature because we're trying to translate a specification for a device
390 	 * and path on that device into a unix path, or at the very least, a
391 	 * geom device : path-on-device.
392 	 *
393 	 * Also, ZFS throws a bit of a monkey wrench in here since it doesn't have
394 	 * a device path type (it creates a new virtual device out of one or more
395 	 * storage devices).
396 	 *
397 	 * For all of them, we'll need to know the geoms, so allocate / free the
398 	 * geom mesh here since it's safer than doing it in each sub-function
399 	 * which may have many error exits.
400 	 */
401 	if (geom_gettree(&mesh))
402 		return (ENOMEM);
403 
404 	rv = EINVAL;
405 	if (DevicePathSubType(walker) == MEDIA_HARDDRIVE_DP)
406 		rv = efi_hd_to_unix(&mesh, walker, dev, relpath, abspath);
407 #ifdef notyet
408 	else if (is_cdrom_device(walker))
409 		rv = efi_cdrom_to_unix(&mesh, walker, dev, relpath, abspath);
410 	else if (is_floppy_device(walker))
411 		rv = efi_floppy_to_unix(&mesh, walker, dev, relpath, abspath);
412 	else if (is_zpool_device(walker))
413 		rv = efi_zpool_to_unix(&mesh, walker, dev, relpath, abspath);
414 #endif
415 	geom_deletetree(&mesh);
416 
417 	return (rv);
418 }
419 
420 /*
421  * Construct the EFI path to a current unix path as follows.
422  *
423  * The path may be of one of three forms:
424  *	1) /path/to/file -- full path to a file. The file need not be present,
425  *		but /path/to must be. It must reside on a local filesystem
426  *		mounted on a GPT or MBR partition.
427  *	2) //path/to/file -- Shorthand for 'On the EFI partition, \path\to\file'
428  *		where 'The EFI Partition' is a partition that's type is 'efi'
429  *		on the same disk that / is mounted from. If there are multiple
430  *		or no 'efi' parittions on that disk, or / isn't on a disk that
431  *		we can trace back to a physical device, an error will result
432  *	3) [/dev/]geom-name:/path/to/file -- Use the specified partition
433  *		(and it must be a GPT or MBR partition) with the specified
434  *		path. The latter is not authenticated.
435  * all path forms translate any \ characters to / before further processing.
436  * When a file path node is created, all / characters are translated back
437  * to \.
438  *
439  * For paths of the first form:
440  *	find where the filesystem is mount (either the file directly, or
441  *		its parent directory).
442  *	translate any logical device name (eg lable) to a physical one
443  *	If not possible, return ENXIO
444  *	If the physical path is unsupported (Eg not on a GPT or MBR disk),
445  *		return ENXIO
446  *	Create a media device path node.
447  *	append the relative path from the mountpoint to the media device node
448  * 		as a file path.
449  *
450  * For paths matching the second form:
451  *	find the EFI partition corresponding to the root fileystem.
452  *	If none found, return ENXIO
453  *	Create a media device path node for the found partition
454  *	Append a File Path to the end for the rest of the file.
455  *
456  * For paths of the third form
457  *	Translate the geom-name passed in into a physical partition
458  *		name.
459  *	Return ENXIO if the translation fails
460  *	Make a media device path for it
461  *	append the part after the : as a File path node.
462  */
463 
464 static char *
465 path_to_file_dp(const char *relpath)
466 {
467 	char *rv;
468 
469 	asprintf(&rv, "File(%s)", relpath);
470 	return rv;
471 }
472 
473 static char *
474 find_geom_efi_on_root(struct gmesh *mesh)
475 {
476 	struct statfs buf;
477 	const char *dev;
478 	struct gprovider *pp;
479 //	struct ggeom *disk;
480 	struct gconsumer *cp;
481 
482 	/*
483 	 * Find /'s geom. Assume it's mounted on /dev/ and filter out all the
484 	 * filesystems that aren't.
485 	 */
486 	if (statfs("/", &buf) != 0)
487 		return (NULL);
488 	dev = buf.f_mntfromname;
489 	if (*dev != '/' || strncmp(dev, _PATH_DEV, sizeof(_PATH_DEV) - 1) != 0)
490 		return (NULL);
491 	dev += sizeof(_PATH_DEV) -1;
492 	pp = find_provider_by_name(mesh, dev);
493 	if (pp == NULL)
494 		return (NULL);
495 
496 	/*
497 	 * If the provider is a LABEL, find it's outer PART class, if any. We
498 	 * only operate on partitions.
499 	 */
500 	if (strcmp(pp->lg_geom->lg_class->lg_name, G_LABEL) == 0) {
501 		LIST_FOREACH(cp, &pp->lg_consumers, lg_consumer) {
502 			if (strcmp(cp->lg_provider->lg_geom->lg_class->lg_name, G_PART) == 0) {
503 				pp = cp->lg_provider;
504 				break;
505 			}
506 		}
507 	}
508 	if (strcmp(pp->lg_geom->lg_class->lg_name, G_PART) != 0)
509 		return (NULL);
510 
511 #if 0
512 	/* This doesn't work because we can't get the data to walk UP the tree it seems */
513 
514 	/*
515 	 * Now that we've found the PART that we have mounted as root, find the
516 	 * first efi typed partition that's a peer, if any.
517 	 */
518 	LIST_FOREACH(cp, &pp->lg_consumers, lg_consumer) {
519 		if (strcmp(cp->lg_provider->lg_geom->lg_class->lg_name, G_DISK) == 0) {
520 			disk = cp->lg_provider->lg_geom;
521 			break;
522 		}
523 	}
524 	if (disk == NULL)	/* This is very bad -- old nested partitions -- no support ? */
525 		return (NULL);
526 #endif
527 
528 #if 0
529 	/* This doesn't work because we can't get the data to walk UP the tree it seems */
530 
531 	/*
532 	 * With the disk provider, we can look for its consumers to see if any are the proper type.
533 	 */
534 	LIST_FOREACH(pp, &disk->lg_consumer, lg_consumer) {
535 		type = geom_pp_attr(mesh, pp, "type");
536 		if (type == NULL)
537 			continue;
538 		if (strcmp(type, "efi") != 0)
539 			continue;
540 		efimedia = geom_pp_attr(mesh, pp, "efimedia");
541 		if (efimedia == NULL)
542 			return (NULL);
543 		return strdup(efimedia);
544 	}
545 #endif
546 	return (NULL);
547 }
548 
549 
550 static char *
551 find_geom_efimedia(struct gmesh *mesh, const char *dev)
552 {
553 	struct gprovider *pp;
554 	const char *efimedia;
555 
556 	pp = find_provider_by_name(mesh, dev);
557 	if (pp == NULL)
558 		return (NULL);
559 	efimedia = geom_pp_attr(mesh, pp, "efimedia");
560 
561 	/*
562 	 * If this device doesn't hav an efimedia attribute, see if it is a
563 	 * glabel node, and if so look for the underlying provider to get the
564 	 * efimedia attribute from.
565 	 */
566 	if (efimedia == NULL &&
567 	    strcmp(pp->lg_geom->lg_class->lg_name, G_LABEL) == 0)
568 		efimedia = find_geom_efimedia(mesh, pp->lg_geom->lg_name);
569 	if (efimedia == NULL)
570 		return (NULL);
571 	return strdup(efimedia);
572 }
573 
574 static int
575 build_dp(const char *efimedia, const char *relpath, efidp *dp)
576 {
577 	char *fp = NULL, *dptxt = NULL, *cp, *rp = NULL;
578 	int rv = 0;
579 	efidp out = NULL;
580 	size_t len;
581 
582 	if (relpath != NULL) {
583 		rp = strdup(relpath);
584 		for (cp = rp; *cp; cp++)
585 			if (*cp == '/')
586 				*cp = '\\';
587 		fp = path_to_file_dp(rp);
588 		free(rp);
589 		if (fp == NULL) {
590 			rv = ENOMEM;
591 			goto errout;
592 		}
593 	}
594 
595 	asprintf(&dptxt, "%s/%s", efimedia, fp == NULL ? "" : fp);
596 	out = malloc(8192);
597 	len = efidp_parse_device_path(dptxt, out, 8192);
598 	if (len > 8192) {
599 		rv = ENOMEM;
600 		goto errout;
601 	}
602 	if (len == 0) {
603 		rv = EINVAL;
604 		goto errout;
605 	}
606 
607 	*dp = out;
608 errout:
609 	if (rv) {
610 		free(out);
611 	}
612 	free(dptxt);
613 	free(fp);
614 
615 	return rv;
616 }
617 
618 /* Handles //path/to/file */
619 /*
620  * Which means: find the disk that has /. Then look for a EFI partition
621  * and use that for the efimedia and /path/to/file as relative to that.
622  * Not sure how ZFS will work here since we can't easily make the leap
623  * to the geom from the zpool.
624  */
625 static int
626 efipart_to_dp(struct gmesh *mesh, char *path, efidp *dp)
627 {
628 	char *efimedia = NULL;
629 	int rv;
630 
631 	efimedia = find_geom_efi_on_root(mesh);
632 #ifdef notyet
633 	if (efimedia == NULL)
634 		efimedia = find_efi_on_zfsroot(dev);
635 #endif
636 	if (efimedia == NULL) {
637 		rv = ENOENT;
638 		goto errout;
639 	}
640 
641 	rv = build_dp(efimedia, path + 1, dp);
642 errout:
643 	free(efimedia);
644 
645 	return rv;
646 }
647 
648 /* Handles [/dev/]geom:[/]path/to/file */
649 /* Handles zfs-dataset:[/]path/to/file (this may include / ) */
650 static int
651 dev_path_to_dp(struct gmesh *mesh, char *path, efidp *dp)
652 {
653 	char *relpath, *dev, *efimedia = NULL;
654 	int rv = 0;
655 
656 	relpath = strchr(path, ':');
657 	assert(relpath != NULL);
658 	*relpath++ = '\0';
659 
660 	dev = path;
661 	if (strncmp(dev, _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
662 		dev += sizeof(_PATH_DEV) -1;
663 
664 	efimedia = find_geom_efimedia(mesh, dev);
665 #ifdef notyet
666 	if (efimedia == NULL)
667 		find_zfs_efi_media(dev);
668 #endif
669 	if (efimedia == NULL) {
670 		rv = ENOENT;
671 		goto errout;
672 	}
673 	rv = build_dp(efimedia, relpath, dp);
674 errout:
675 	free(efimedia);
676 
677 	return rv;
678 }
679 
680 /* Handles /path/to/file */
681 /* Handles /dev/foo/bar */
682 static int
683 path_to_dp(struct gmesh *mesh, char *path, efidp *dp)
684 {
685 	struct statfs buf;
686 	char *rp = NULL, *ep, *dev, *efimedia = NULL;
687 	int rv = 0;
688 
689 	rp = realpath(path, NULL);
690 	if (rp == NULL) {
691 		rv = errno;
692 		goto errout;
693 	}
694 
695 	if (statfs(rp, &buf) != 0) {
696 		rv = errno;
697 		goto errout;
698 	}
699 
700 	dev = buf.f_mntfromname;
701 	/*
702 	 * If we're fed a raw /dev/foo/bar, then devfs is returned from the
703 	 * statfs call. In that case, use that dev and assume we have a path
704 	 * of nothing.
705 	 */
706 	if (strcmp(dev, "devfs") == 0) {
707 		dev = rp + sizeof(_PATH_DEV) - 1;
708 		ep = NULL;
709 	} else {
710 		if (strncmp(dev, _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
711 			dev += sizeof(_PATH_DEV) - 1;
712 		ep = rp + strlen(buf.f_mntonname);
713 	}
714 
715 	efimedia = find_geom_efimedia(mesh, dev);
716 #ifdef notyet
717 	if (efimedia == NULL)
718 		find_zfs_efi_media(dev);
719 #endif
720 	if (efimedia == NULL) {
721 		rv = ENOENT;
722 		goto errout;
723 	}
724 
725 	rv = build_dp(efimedia, ep, dp);
726 errout:
727 	free(efimedia);
728 	free(rp);
729 	if (rv != 0) {
730 		free(*dp);
731 		*dp = NULL;
732 	}
733 	return (rv);
734 }
735 
736 int
737 efivar_unix_path_to_device_path(const char *path, efidp *dp)
738 {
739 	char *modpath = NULL, *cp;
740 	int rv = ENOMEM;
741 	struct gmesh mesh;
742 
743 	/*
744 	 * Fail early for clearly bogus things
745 	 */
746 	if (path == NULL || dp == NULL)
747 		return (EDOOFUS);
748 
749 	/*
750 	 * We'll need the goem mesh to grovel through it to find the
751 	 * efimedia attribute for any devices we find. Grab it here
752 	 * and release it to simplify the error paths out of the
753 	 * subordinate functions
754 	 */
755 	if (geom_gettree(&mesh))
756 		return (errno);
757 
758 	/*
759 	 * Convert all \ to /. We'll convert them back again when
760 	 * we encode the file. Boot loaders are expected to cope.
761 	 */
762 	modpath = strdup(path);
763 	if (modpath == NULL)
764 		goto out;
765 	for (cp = modpath; *cp; cp++)
766 		if (*cp == '\\')
767 			*cp = '/';
768 
769 	if (modpath[0] == '/' && modpath[1] == '/')	/* Handle //foo/bar/baz */
770 		rv = efipart_to_dp(&mesh, modpath, dp);
771 	else if (strchr(modpath, ':'))			/* Handle dev:/bar/baz */
772 		rv = dev_path_to_dp(&mesh, modpath, dp);
773 	else						/* Handle /a/b/c */
774 		rv = path_to_dp(&mesh, modpath, dp);
775 
776 out:
777 	geom_deletetree(&mesh);
778 	free(modpath);
779 
780 	return (rv);
781 }
782