xref: /freebsd/stand/i386/zfsboot/zfsboot.c (revision 7ec2f6bce5d28e6662c29e63f6ab6b7ef57d98b2)
1 /*-
2  * Copyright (c) 1998 Robert Nordier
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are freely
6  * permitted provided that the above copyright notice and this
7  * paragraph and the following disclaimer are duplicated in all
8  * such forms.
9  *
10  * This software is provided "AS IS" and without any express or
11  * implied warranties, including, without limitation, the implied
12  * warranties of merchantability and fitness for a particular
13  * purpose.
14  */
15 
16 #include <sys/cdefs.h>
17 __FBSDID("$FreeBSD$");
18 
19 #include <stand.h>
20 
21 #include <sys/param.h>
22 #include <sys/errno.h>
23 #include <sys/diskmbr.h>
24 #ifdef GPT
25 #include <sys/gpt.h>
26 #endif
27 #include <sys/reboot.h>
28 #include <sys/queue.h>
29 #ifdef LOADER_ZFS_SUPPORT
30 #include <sys/zfs_bootenv.h>
31 #endif
32 
33 #include <machine/bootinfo.h>
34 #include <machine/elf.h>
35 #include <machine/pc/bios.h>
36 
37 #include <stdarg.h>
38 #include <stddef.h>
39 
40 #include <a.out.h>
41 #include "bootstrap.h"
42 #include "libi386.h"
43 #include <btxv86.h>
44 
45 #include "lib.h"
46 #include "rbx.h"
47 #include "cons.h"
48 #include "bootargs.h"
49 #include "disk.h"
50 #include "part.h"
51 #include "paths.h"
52 
53 #include "libzfs.h"
54 
55 #define	ARGS			0x900
56 #define	NOPT			14
57 #define	NDEV			3
58 
59 #define	BIOS_NUMDRIVES		0x475
60 #define	DRV_HARD		0x80
61 #define	DRV_MASK		0x7f
62 
63 #define	TYPE_AD			0
64 #define	TYPE_DA			1
65 #define	TYPE_MAXHARD		TYPE_DA
66 #define	TYPE_FD			2
67 
68 extern uint32_t _end;
69 
70 static const char optstr[NOPT] = "DhaCcdgmnpqrsv"; /* Also 'P', 'S' */
71 static const unsigned char flags[NOPT] = {
72     RBX_DUAL,
73     RBX_SERIAL,
74     RBX_ASKNAME,
75     RBX_CDROM,
76     RBX_CONFIG,
77     RBX_KDB,
78     RBX_GDB,
79     RBX_MUTE,
80     RBX_NOINTR,
81     RBX_PAUSE,
82     RBX_QUIET,
83     RBX_DFLTROOT,
84     RBX_SINGLE,
85     RBX_VERBOSE
86 };
87 uint32_t opts;
88 
89 /*
90  * Paths to try loading before falling back to the boot2 prompt.
91  *
92  * /boot/zfsloader must be tried before /boot/loader in order to remain
93  * backward compatible with ZFS boot environments where /boot/loader exists
94  * but does not have ZFS support, which was the case before FreeBSD 12.
95  *
96  * If no loader is found, try to load a kernel directly instead.
97  */
98 static const struct string {
99 	const char *p;
100 	size_t len;
101 } loadpath[] = {
102 	{ PATH_LOADER_ZFS, sizeof(PATH_LOADER_ZFS) },
103 	{ PATH_LOADER, sizeof(PATH_LOADER) },
104 	{ PATH_KERNEL, sizeof(PATH_KERNEL) },
105 };
106 
107 static const unsigned char dev_maj[NDEV] = {30, 4, 2};
108 
109 static struct i386_devdesc *bdev;
110 static char cmd[512];
111 static char cmddup[512];
112 static char kname[1024];
113 static int comspeed = SIOSPD;
114 static struct bootinfo bootinfo;
115 static uint32_t bootdev;
116 static struct zfs_boot_args zfsargs;
117 #ifdef LOADER_GELI_SUPPORT
118 static struct geli_boot_args geliargs;
119 #endif
120 
121 extern vm_offset_t high_heap_base;
122 extern uint32_t	bios_basemem, bios_extmem, high_heap_size;
123 
124 static char *heap_top;
125 static char *heap_bottom;
126 
127 void exit(int);
128 static void i386_zfs_probe(void);
129 static void load(void);
130 static int parse_cmd(void);
131 
132 #ifdef LOADER_GELI_SUPPORT
133 #include "geliboot.h"
134 static char gelipw[GELI_PW_MAXLEN];
135 #endif
136 
137 struct arch_switch archsw;	/* MI/MD interface boundary */
138 static char boot_devname[2 * ZFS_MAXNAMELEN + 8]; /* disk or pool:dataset */
139 
140 struct devsw *devsw[] = {
141 	&bioshd,
142 #if defined(LOADER_ZFS_SUPPORT)
143 	&zfs_dev,
144 #endif
145 	NULL
146 };
147 
148 struct fs_ops *file_system[] = {
149 #if defined(LOADER_ZFS_SUPPORT)
150 	&zfs_fsops,
151 #endif
152 #if defined(LOADER_UFS_SUPPORT)
153 	&ufs_fsops,
154 #endif
155 	NULL
156 };
157 
158 caddr_t
159 ptov(uintptr_t x)
160 {
161 	return (PTOV(x));
162 }
163 
164 int
165 main(void)
166 {
167 	unsigned i;
168 	int auto_boot, fd, nextboot = 0;
169 	struct disk_devdesc devdesc;
170 
171 	bios_getmem();
172 
173 	if (high_heap_size > 0) {
174 		heap_top = PTOV(high_heap_base + high_heap_size);
175 		heap_bottom = PTOV(high_heap_base);
176 	} else {
177 		heap_bottom = (char *)
178 		    (roundup2(__base + (int32_t)&_end, 0x10000) - __base);
179 		heap_top = (char *)PTOV(bios_basemem);
180 	}
181 	setheap(heap_bottom, heap_top);
182 
183 	/*
184 	 * Initialise the block cache. Set the upper limit.
185 	 */
186 	bcache_init(32768, 512);
187 
188 	archsw.arch_autoload = NULL;
189 	archsw.arch_getdev = i386_getdev;
190 	archsw.arch_copyin = NULL;
191 	archsw.arch_copyout = NULL;
192 	archsw.arch_readin = NULL;
193 	archsw.arch_isainb = NULL;
194 	archsw.arch_isaoutb = NULL;
195 	archsw.arch_zfs_probe = i386_zfs_probe;
196 
197 	bootinfo.bi_version = BOOTINFO_VERSION;
198 	bootinfo.bi_size = sizeof(bootinfo);
199 	bootinfo.bi_basemem = bios_basemem / 1024;
200 	bootinfo.bi_extmem = bios_extmem / 1024;
201 	bootinfo.bi_memsizes_valid++;
202 	bootinfo.bi_bios_dev = *(uint8_t *)PTOV(ARGS);
203 
204 	/* Set up fall back device name. */
205 	snprintf(boot_devname, sizeof (boot_devname), "disk%d:",
206 	    bd_bios2unit(bootinfo.bi_bios_dev));
207 
208 	for (i = 0; devsw[i] != NULL; i++)
209 		if (devsw[i]->dv_init != NULL)
210 			(devsw[i]->dv_init)();
211 
212 	disk_parsedev(&devdesc, boot_devname + 4, NULL);
213 
214 	bootdev = MAKEBOOTDEV(dev_maj[DEVT_DISK], devdesc.d_slice + 1,
215 	    devdesc.dd.d_unit,
216 	    devdesc.d_partition >= 0 ? devdesc.d_partition : 0xff);
217 
218 	/*
219 	 * zfs_fmtdev() can be called only after dv_init
220 	 */
221 	if (bdev != NULL && bdev->dd.d_dev->dv_type == DEVT_ZFS) {
222 		/* set up proper device name string for ZFS */
223 		strncpy(boot_devname, zfs_fmtdev(bdev), sizeof (boot_devname));
224 		if (zfs_get_bootonce(bdev, OS_BOOTONCE, cmd,
225 		    sizeof(cmd)) == 0) {
226 			nvlist_t *benv;
227 
228 			nextboot = 1;
229 			memcpy(cmddup, cmd, sizeof(cmd));
230 			if (parse_cmd()) {
231 				if (!OPT_CHECK(RBX_QUIET))
232 					printf("failed to parse bootonce "
233 					    "command\n");
234 				exit(0);
235 			}
236 			if (!OPT_CHECK(RBX_QUIET))
237 				printf("zfs bootonce: %s\n", cmddup);
238 
239 			if (zfs_get_bootenv(bdev, &benv) == 0) {
240 				nvlist_add_string(benv, OS_BOOTONCE_USED,
241 				    cmddup);
242 				zfs_set_bootenv(bdev, benv);
243 			}
244 			/* Do not process this command twice */
245 			*cmd = 0;
246 		}
247 	}
248 
249 	/* now make sure we have bdev on all cases */
250 	free(bdev);
251 	i386_getdev((void **)&bdev, boot_devname, NULL);
252 
253 	env_setenv("currdev", EV_VOLATILE, boot_devname, i386_setcurrdev,
254 	    env_nounset);
255 
256 	/* Process configuration file */
257 	auto_boot = 1;
258 
259 	fd = open(PATH_CONFIG, O_RDONLY);
260 	if (fd == -1)
261 		fd = open(PATH_DOTCONFIG, O_RDONLY);
262 
263 	if (fd != -1) {
264 		ssize_t cmdlen;
265 
266 		if ((cmdlen = read(fd, cmd, sizeof(cmd))) > 0)
267 			cmd[cmdlen] = '\0';
268 		else
269 			*cmd = '\0';
270 		close(fd);
271 	}
272 
273 	if (*cmd) {
274 		/*
275 		 * Note that parse_cmd() is destructive to cmd[] and we also
276 		 * want to honor RBX_QUIET option that could be present in
277 		 * cmd[].
278 		 */
279 		memcpy(cmddup, cmd, sizeof(cmd));
280 		if (parse_cmd())
281 			auto_boot = 0;
282 		if (!OPT_CHECK(RBX_QUIET))
283 			printf("%s: %s\n", PATH_CONFIG, cmddup);
284 		/* Do not process this command twice */
285 		*cmd = 0;
286 	}
287 
288 	/* Do not risk waiting at the prompt forever. */
289 	if (nextboot && !auto_boot)
290 		exit(0);
291 
292 	if (auto_boot && !*kname) {
293 		/*
294 		 * Iterate through the list of loader and kernel paths,
295 		 * trying to load. If interrupted by a keypress, or in case of
296 		 * failure, drop the user to the boot2 prompt.
297 		 */
298 		for (i = 0; i < nitems(loadpath); i++) {
299 			memcpy(kname, loadpath[i].p, loadpath[i].len);
300 			if (keyhit(3))
301 				break;
302 			load();
303 		}
304 	}
305 
306 	/* Present the user with the boot2 prompt. */
307 
308 	for (;;) {
309 		if (!auto_boot || !OPT_CHECK(RBX_QUIET)) {
310 			printf("\nFreeBSD/x86 boot\n");
311 			printf("Default: %s%s\nboot: ", boot_devname, kname);
312 		}
313 		if (ioctrl & IO_SERIAL)
314 			sio_flush();
315 		if (!auto_boot || keyhit(5))
316 			getstr(cmd, sizeof(cmd));
317 		else if (!auto_boot || !OPT_CHECK(RBX_QUIET))
318 			putchar('\n');
319 		auto_boot = 0;
320 		if (parse_cmd())
321 			putchar('\a');
322 		else
323 			load();
324 	}
325 }
326 
327 /* XXX - Needed for btxld to link the boot2 binary; do not remove. */
328 void
329 exit(int x)
330 {
331 	__exit(x);
332 }
333 
334 static void
335 load(void)
336 {
337 	union {
338 		struct exec ex;
339 		Elf32_Ehdr eh;
340 	} hdr;
341 	static Elf32_Phdr ep[2];
342 	static Elf32_Shdr es[2];
343 	caddr_t p;
344 	uint32_t addr, x;
345 	int fd, fmt, i, j;
346 	ssize_t size;
347 
348 	if ((fd = open(kname, O_RDONLY)) == -1) {
349 		printf("\nCan't find %s\n", kname);
350 		return;
351 	}
352 
353 	size = sizeof(hdr);
354 	if (read(fd, &hdr, sizeof (hdr)) != size) {
355 		close(fd);
356 		return;
357 	}
358 	if (N_GETMAGIC(hdr.ex) == ZMAGIC) {
359 		fmt = 0;
360 	} else if (IS_ELF(hdr.eh)) {
361 		fmt = 1;
362 	} else {
363 		printf("Invalid %s\n", "format");
364 		close(fd);
365 		return;
366 	}
367 	if (fmt == 0) {
368 		addr = hdr.ex.a_entry & 0xffffff;
369 		p = PTOV(addr);
370 		lseek(fd, PAGE_SIZE, SEEK_SET);
371 		size = hdr.ex.a_text;
372 		if (read(fd, p, hdr.ex.a_text) != size) {
373 			close(fd);
374 			return;
375 		}
376 		p += roundup2(hdr.ex.a_text, PAGE_SIZE);
377 		size = hdr.ex.a_data;
378 		if (read(fd, p, hdr.ex.a_data) != size) {
379 			close(fd);
380 			return;
381 		}
382 		p += hdr.ex.a_data + roundup2(hdr.ex.a_bss, PAGE_SIZE);
383 		bootinfo.bi_symtab = VTOP(p);
384 		memcpy(p, &hdr.ex.a_syms, sizeof(hdr.ex.a_syms));
385 		p += sizeof(hdr.ex.a_syms);
386 		if (hdr.ex.a_syms) {
387 			size = hdr.ex.a_syms;
388 			if (read(fd, p, hdr.ex.a_syms) != size) {
389 				close(fd);
390 				return;
391 			}
392 			p += hdr.ex.a_syms;
393 			size = sizeof (int);
394 			if (read(fd, p, sizeof (int)) != size) {
395 				close(fd);
396 				return;
397 			}
398 			x = *(uint32_t *)p;
399 			p += sizeof(int);
400 			x -= sizeof(int);
401 			size = x;
402 			if (read(fd, p, x) != size) {
403 				close(fd);
404 				return;
405 			}
406 			p += x;
407 		}
408 	} else {
409 		lseek(fd, hdr.eh.e_phoff, SEEK_SET);
410 		for (j = i = 0; i < hdr.eh.e_phnum && j < 2; i++) {
411 			size = sizeof (ep[0]);
412 			if (read(fd, ep + j, sizeof (ep[0])) != size) {
413 				close(fd);
414 				return;
415 			}
416 			if (ep[j].p_type == PT_LOAD)
417 				j++;
418 		}
419 		for (i = 0; i < 2; i++) {
420 			p = PTOV(ep[i].p_paddr & 0xffffff);
421 			lseek(fd, ep[i].p_offset, SEEK_SET);
422 			size = ep[i].p_filesz;
423 			if (read(fd, p, ep[i].p_filesz) != size) {
424 				close(fd);
425 				return;
426 			}
427 		}
428 		p += roundup2(ep[1].p_memsz, PAGE_SIZE);
429 		bootinfo.bi_symtab = VTOP(p);
430 		if (hdr.eh.e_shnum == hdr.eh.e_shstrndx + 3) {
431 			lseek(fd, hdr.eh.e_shoff +
432 			    sizeof (es[0]) * (hdr.eh.e_shstrndx + 1),
433 			    SEEK_SET);
434 			size = sizeof(es);
435 			if (read(fd, &es, sizeof (es)) != size) {
436 				close(fd);
437 				return;
438 			}
439 			for (i = 0; i < 2; i++) {
440 				memcpy(p, &es[i].sh_size,
441 				    sizeof(es[i].sh_size));
442 				p += sizeof(es[i].sh_size);
443 				lseek(fd, es[i].sh_offset, SEEK_SET);
444 				size = es[i].sh_size;
445 				if (read(fd, p, es[i].sh_size) != size) {
446 					close(fd);
447 					return;
448 				}
449 				p += es[i].sh_size;
450 			}
451 		}
452 		addr = hdr.eh.e_entry & 0xffffff;
453 	}
454 	close(fd);
455 
456 	bootinfo.bi_esymtab = VTOP(p);
457 	bootinfo.bi_kernelname = VTOP(kname);
458 #ifdef LOADER_GELI_SUPPORT
459 	explicit_bzero(gelipw, sizeof(gelipw));
460 #endif
461 
462 	if (bdev->dd.d_dev->dv_type == DEVT_ZFS) {
463 		zfsargs.size = sizeof(zfsargs);
464 		zfsargs.pool = bdev->d_kind.zfs.pool_guid;
465 		zfsargs.root = bdev->d_kind.zfs.root_guid;
466 #ifdef LOADER_GELI_SUPPORT
467 		export_geli_boot_data(&zfsargs.gelidata);
468 #endif
469 		/*
470 		 * Note that the zfsargs struct is passed by value, not by
471 		 * pointer. Code in btxldr.S copies the values from the entry
472 		 * stack to a fixed location within loader(8) at startup due
473 		 * to the presence of KARGS_FLAGS_EXTARG.
474 		 */
475 		__exec((caddr_t)addr, RB_BOOTINFO | (opts & RBX_MASK),
476 		    bootdev,
477 		    KARGS_FLAGS_ZFS | KARGS_FLAGS_EXTARG,
478 		    (uint32_t)bdev->d_kind.zfs.pool_guid,
479 		    (uint32_t)(bdev->d_kind.zfs.pool_guid >> 32),
480 		    VTOP(&bootinfo),
481 		    zfsargs);
482 	} else {
483 #ifdef LOADER_GELI_SUPPORT
484 		geliargs.size = sizeof(geliargs);
485 		export_geli_boot_data(&geliargs.gelidata);
486 #endif
487 
488 		/*
489 		 * Note that the geliargs struct is passed by value, not by
490 		 * pointer. Code in btxldr.S copies the values from the entry
491 		 * stack to a fixed location within loader(8) at startup due
492 		 * to the presence of the KARGS_FLAGS_EXTARG flag.
493 		 */
494 		__exec((caddr_t)addr, RB_BOOTINFO | (opts & RBX_MASK),
495 		    bootdev,
496 #ifdef LOADER_GELI_SUPPORT
497 		    KARGS_FLAGS_GELI | KARGS_FLAGS_EXTARG, 0, 0,
498 		    VTOP(&bootinfo), geliargs
499 #else
500 		    0, 0, 0, VTOP(&bootinfo)
501 #endif
502 		    );
503 	}
504 }
505 
506 static int
507 mount_root(char *arg)
508 {
509 	char *root;
510 	struct i386_devdesc *ddesc;
511 	uint8_t part;
512 
513 	if (asprintf(&root, "%s:", arg) < 0)
514 		return (1);
515 
516 	if (i386_getdev((void **)&ddesc, root, NULL)) {
517 		free(root);
518 		return (1);
519 	}
520 
521 	/* we should have new device descriptor, free old and replace it. */
522 	free(bdev);
523 	bdev = ddesc;
524 	if (bdev->dd.d_dev->dv_type == DEVT_DISK) {
525 		if (bdev->d_kind.biosdisk.partition == -1)
526 			part = 0xff;
527 		else
528 			part = bdev->d_kind.biosdisk.partition;
529 		bootdev = MAKEBOOTDEV(dev_maj[bdev->dd.d_dev->dv_type],
530 		    bdev->d_kind.biosdisk.slice + 1,
531 		    bdev->dd.d_unit, part);
532 		bootinfo.bi_bios_dev = bd_unit2bios(bdev);
533 	}
534 	strncpy(boot_devname, root, sizeof (boot_devname));
535 	setenv("currdev", root, 1);
536 	free(root);
537 	return (0);
538 }
539 
540 static void
541 fs_list(char *arg)
542 {
543 	int fd;
544 	struct dirent *d;
545 	char line[80];
546 
547 	fd = open(arg, O_RDONLY);
548 	if (fd < 0)
549 		return;
550 	pager_open();
551 	while ((d = readdirfd(fd)) != NULL) {
552 		sprintf(line, "%s\n", d->d_name);
553 		if (pager_output(line))
554 			break;
555 	}
556 	pager_close();
557 	close(fd);
558 }
559 
560 static int
561 parse_cmd(void)
562 {
563 	char *arg = cmd;
564 	char *ep, *p, *q;
565 	const char *cp;
566 	char line[80];
567 	int c, i, j;
568 
569 	while ((c = *arg++)) {
570 		if (c == ' ' || c == '\t' || c == '\n')
571 			continue;
572 		for (p = arg; *p && *p != '\n' && *p != ' ' && *p != '\t'; p++)
573 			;
574 		ep = p;
575 		if (*p)
576 			*p++ = 0;
577 		if (c == '-') {
578 			while ((c = *arg++)) {
579 				if (c == 'P') {
580 					if (*(uint8_t *)PTOV(0x496) & 0x10) {
581 						cp = "yes";
582 					} else {
583 						opts |= OPT_SET(RBX_DUAL);
584 						opts |= OPT_SET(RBX_SERIAL);
585 						cp = "no";
586 					}
587 					printf("Keyboard: %s\n", cp);
588 					continue;
589 				} else if (c == 'S') {
590 					j = 0;
591 					while ((unsigned int)
592 					    (i = *arg++ - '0') <= 9)
593 						j = j * 10 + i;
594 					if (j > 0 && i == -'0') {
595 						comspeed = j;
596 						break;
597 					}
598 					/*
599 					 * Fall through to error below
600 					 * ('S' not in optstr[]).
601 					 */
602 				}
603 				for (i = 0; c != optstr[i]; i++)
604 					if (i == NOPT - 1)
605 						return (-1);
606 				opts ^= OPT_SET(flags[i]);
607 			}
608 			ioctrl = OPT_CHECK(RBX_DUAL) ? (IO_SERIAL|IO_KEYBOARD) :
609 			    OPT_CHECK(RBX_SERIAL) ? IO_SERIAL : IO_KEYBOARD;
610 			if (ioctrl & IO_SERIAL) {
611 				if (sio_init(115200 / comspeed) != 0)
612 					ioctrl &= ~IO_SERIAL;
613 			}
614 		} if (c == '?') {
615 			printf("\n");
616 			if (*arg == '\0')
617 				arg = (char *)"/";
618 			fs_list(arg);
619 			zfs_list(arg);
620 			return (-1);
621 		} else {
622 			char *ptr;
623 			printf("\n");
624 			arg--;
625 
626 			/*
627 			 * Report pool status if the comment is 'status'. Lets
628 			 * hope no-one wants to load /status as a kernel.
629 			 */
630 			if (strcmp(arg, "status") == 0) {
631 				pager_open();
632 				for (i = 0; devsw[i] != NULL; i++) {
633 					if (devsw[i]->dv_print != NULL) {
634 						if (devsw[i]->dv_print(1))
635 							break;
636 					} else {
637 						snprintf(line, sizeof(line),
638 						    "%s: (unknown)\n",
639 						    devsw[i]->dv_name);
640 						if (pager_output(line))
641 							break;
642 					}
643 				}
644 				pager_close();
645 				return (-1);
646 			}
647 
648 			/*
649 			 * If there is "zfs:" prefix simply ignore it.
650 			 */
651 			ptr = arg;
652 			if (strncmp(ptr, "zfs:", 4) == 0)
653 				ptr += 4;
654 
655 			/*
656 			 * If there is a colon, switch pools.
657 			 */
658 			q = strchr(ptr, ':');
659 			if (q) {
660 				*q++ = '\0';
661 				if (mount_root(arg) != 0) {
662 					return (-1);
663 				}
664 				arg = q;
665 			}
666 			if ((i = ep - arg)) {
667 				if ((size_t)i >= sizeof(kname))
668 					return (-1);
669 				memcpy(kname, arg, i + 1);
670 			}
671 		}
672 		arg = p;
673 	}
674 	return (0);
675 }
676 
677 /*
678  * Probe all disks to discover ZFS pools. The idea is to walk all possible
679  * disk devices, however, we also need to identify possible boot pool.
680  * For boot pool detection we have boot disk passed us from BIOS, recorded
681  * in bootinfo.bi_bios_dev.
682  */
683 static void
684 i386_zfs_probe(void)
685 {
686 	char devname[32];
687 	int boot_unit;
688 	struct i386_devdesc dev;
689 	uint64_t pool_guid = 0;
690 
691 	dev.dd.d_dev = &bioshd;
692 	/* Translate bios dev to our unit number. */
693 	boot_unit = bd_bios2unit(bootinfo.bi_bios_dev);
694 
695 	/*
696 	 * Open all the disks we can find and see if we can reconstruct
697 	 * ZFS pools from them.
698 	 */
699 	for (dev.dd.d_unit = 0; bd_unit2bios(&dev) >= 0; dev.dd.d_unit++) {
700 		snprintf(devname, sizeof (devname), "%s%d:", bioshd.dv_name,
701 		    dev.dd.d_unit);
702 		/* If this is not boot disk, use generic probe. */
703 		if (dev.dd.d_unit != boot_unit)
704 			zfs_probe_dev(devname, NULL);
705 		else
706 			zfs_probe_dev(devname, &pool_guid);
707 
708 		if (pool_guid != 0 && bdev == NULL) {
709 			bdev = malloc(sizeof (struct i386_devdesc));
710 			bzero(bdev, sizeof (struct i386_devdesc));
711 			bdev->dd.d_dev = &zfs_dev;
712 			bdev->d_kind.zfs.pool_guid = pool_guid;
713 		}
714 	}
715 }
716