xref: /titanic_41/usr/src/cmd/fs.d/pcfs/fsck/pcfs_common.c (revision 9e86db79b7d1bbc5f2f04e99954cbd5eae0e22bb)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*
27  * fsck_pcfs -- common.c
28  *	All the routines in this file are being swiped directly from
29  *	mkfs_pcfs.  Eventually this file should only exist in one place
30  *	and be part of a library that both mkfs and fsck link against.
31  */
32 #include <stdio.h>
33 #include <string.h>
34 #include <unistd.h>
35 #include <stdlib.h>
36 #include <libintl.h>
37 #include <sys/isa_defs.h>
38 #include <sys/types.h>
39 #include <sys/stat.h>
40 #include <sys/fcntl.h>
41 #include <sys/dktp/fdisk.h>
42 #include <sys/fs/pc_fs.h>
43 #include <sys/fs/pc_dir.h>
44 #include <sys/fs/pc_label.h>
45 #include "fsck_pcfs.h"
46 #include "pcfs_common.h"
47 #include "pcfs_bpb.h"
48 
49 /*
50  *	The assumption here is that _BIG_ENDIAN implies sparc, and
51  *	so in addition to swapping bytes we also have to construct
52  *	packed structures by hand to avoid bus errors due to improperly
53  *	aligned pointers.
54  */
55 #ifdef _BIG_ENDIAN
56 void swap_pack_grab32bpb(bpb_t *wbpb, struct _boot_sector *bsp);
57 void swap_pack_grabbpb(bpb_t *wbpb, struct _boot_sector *bsp);
58 #endif /* _BIG_ENDIAN */
59 
60 /*
61  *  Global variables related to input questions
62  */
63 extern int AlwaysYes;
64 extern int AlwaysNo;
65 
66 int
67 is_z_a_power_of_x_le_y(int x, int y, int z)
68 {
69 	int ispower = 0;
70 	int pow = 1;
71 
72 	do {
73 		if (pow == z) {
74 			ispower = 1;
75 			break;
76 		}
77 		pow *= x;
78 	} while (pow <= y);
79 
80 	return (ispower);
81 }
82 
83 /*
84  * store_16_bits
85  *	Save the lower 16 bits of a 32 bit value (v) into the provided
86  *	buffer (pointed at by *bp), and increment the buffer pointer
87  *	as well.  This way the routine can be called multiple times in
88  *	succession to fill buffers.  The value is stored in little-endian
89  *	order.
90  */
91 void
92 store_16_bits(uchar_t **bp, uint32_t v)
93 {
94 	uchar_t *l = *bp;
95 
96 	*l++ = v & 0xff;
97 	*l = (v >> 8) & 0xff;
98 	*bp += 2;
99 }
100 
101 void
102 read_16_bits(uchar_t *bp, uint32_t *value)
103 {
104 	*value = *bp++;
105 	*value += *bp << 8;
106 }
107 
108 /*
109  * store_32_bits
110  * 	Save the 32 bit value (v) into the provided buffer (pointed
111  *	at by *bp), and increment the buffer pointer as well.  This way
112  *	the routine can be called multiple times in succession to fill
113  *	buffers.  The value is stored in little-endian order.
114  */
115 void
116 store_32_bits(uchar_t **bp, uint32_t v)
117 {
118 	uchar_t *l = *bp;
119 	int b;
120 
121 	for (b = 0; b < 4; b++) {
122 		*l++ = v & 0xff;
123 		v = v >> 8;
124 	}
125 	*bp += 4;
126 }
127 
128 void
129 read_32_bits(uchar_t *bp, uint32_t *value)
130 {
131 	*value = *bp++;
132 	*value += *bp++ << 8;
133 	*value += *bp++ << 16;
134 	*value += *bp++ << 24;
135 }
136 
137 /*
138  *  dump_bytes  -- display bytes as hex numbers.
139  *		   b is the pointer to the byte buffer
140  *		   n is the number of bytes in the buffer
141  */
142 /* Note: BPL = bytes to display per line */
143 #define	BPL 16
144 
145 void
146 dump_bytes(uchar_t *buf, int n)
147 {
148 	int printedCount;
149 	int countdown = n;
150 	int countup = 0;
151 	int offset = 0;
152 	int byte;
153 
154 	/* Display offset, 16 bytes per line, and printable ascii version */
155 	while (countdown > 0) {
156 		printedCount = 0;
157 		(void) fprintf(stderr, "\n%06x: ", offset);
158 		/*
159 		 * Print Hex value of characters in columns on left
160 		 */
161 		for (byte = 0; byte < BPL; byte++) {
162 			if (countup + byte < n) {
163 				(void) fprintf(stderr,
164 				    "%02x ", (buf[countup + byte] & 0xff));
165 				printedCount++;
166 			} else {
167 				(void) fprintf(stderr, "   ");
168 			}
169 		}
170 		/*
171 		 * Right side has the printable character or '.' for
172 		 * unprintable for each column of the left.
173 		 */
174 		for (byte = 0; byte < BPL; byte++) {
175 			if ((countup + byte < n) &&
176 			    ((buf[countup + byte] >= ' ') &&
177 			    (buf[countup + byte] <= '~'))) {
178 				(void) fprintf(stderr, "%c",
179 				    buf[countup + byte]);
180 			} else {
181 				(void) fprintf(stderr, ".");
182 			}
183 		}
184 		countup += printedCount;
185 		offset += printedCount;
186 		countdown -= printedCount;
187 	}
188 	(void) fprintf(stderr, "\n\n");
189 }
190 
191 /*
192  *  header_for_dump  --  display simple header over what will be output.
193  */
194 void
195 header_for_dump(void)
196 {
197 	int byte;
198 
199 	(void) fprintf(stderr, "\n        ");
200 	for (byte = 0; byte < BPL; byte++)
201 		(void) fprintf(stderr, "%02x ", byte);
202 	(void) fprintf(stderr, "\n       ");
203 	byte = 3*BPL;
204 	while (byte-- > 0)
205 		(void) fprintf(stderr, "-");
206 }
207 
208 /*
209  *  We are basically (incorrectly) assuming that if you aren't running
210  *  on x86 the BPB has to be packed by hand AND that the bytes must
211  *  be swapped.  One or both of these assumptions may one day be invalid.
212  *  (if they aren't already :-))
213  */
214 #ifdef _BIG_ENDIAN
215 /*
216  *  swap_pack_grab{32}bpb
217  *	If not on an x86 we assume the structures making up the bpb
218  *	were not packed and that longs and shorts need to be byte swapped
219  *	(we've kept everything in host order up until now).  A new architecture
220  *	might not need to swap or might not need to pack, in which case
221  *	new routines will have to be written.  Of course if an architecture
222  *	supports both packing and little-endian host order, it can follow the
223  *	same path as the x86 code.
224  */
225 void
226 swap_pack_grabbpb(bpb_t *wbpb, struct _boot_sector *bsp)
227 {
228 	uchar_t *grabp;
229 
230 	grabp = (uchar_t *)&(bsp->bs_filler[ORIG_BPB_START_INDEX]);
231 
232 	((uchar_t *)&(wbpb->bpb.bytes_per_sector))[1] = *grabp++;
233 	((uchar_t *)&(wbpb->bpb.bytes_per_sector))[0] = *grabp++;
234 	wbpb->bpb.sectors_per_cluster = *grabp++;
235 	((uchar_t *)&(wbpb->bpb.resv_sectors))[1] = *grabp++;
236 	((uchar_t *)&(wbpb->bpb.resv_sectors))[0] = *grabp++;
237 	wbpb->bpb.num_fats = *grabp++;
238 	((uchar_t *)&(wbpb->bpb.num_root_entries))[1] = *grabp++;
239 	((uchar_t *)&(wbpb->bpb.num_root_entries))[0] = *grabp++;
240 	((uchar_t *)&(wbpb->bpb.sectors_in_volume))[1] = *grabp++;
241 	((uchar_t *)&(wbpb->bpb.sectors_in_volume))[0] = *grabp++;
242 	wbpb->bpb.media = *grabp++;
243 	((uchar_t *)&(wbpb->bpb.sectors_per_fat))[1] = *grabp++;
244 	((uchar_t *)&(wbpb->bpb.sectors_per_fat))[0] = *grabp++;
245 	((uchar_t *)&(wbpb->bpb.sectors_per_track))[1] = *grabp++;
246 	((uchar_t *)&(wbpb->bpb.sectors_per_track))[0] = *grabp++;
247 	((uchar_t *)&(wbpb->bpb.heads))[1] = *grabp++;
248 	((uchar_t *)&(wbpb->bpb.heads))[0] = *grabp++;
249 	((uchar_t *)&(wbpb->bpb.hidden_sectors))[3] = *grabp++;
250 	((uchar_t *)&(wbpb->bpb.hidden_sectors))[2] = *grabp++;
251 	((uchar_t *)&(wbpb->bpb.hidden_sectors))[1] = *grabp++;
252 	((uchar_t *)&(wbpb->bpb.hidden_sectors))[0] = *grabp++;
253 	((uchar_t *)&(wbpb->bpb.sectors_in_logical_volume))[3] = *grabp++;
254 	((uchar_t *)&(wbpb->bpb.sectors_in_logical_volume))[2] = *grabp++;
255 	((uchar_t *)&(wbpb->bpb.sectors_in_logical_volume))[1] = *grabp++;
256 	((uchar_t *)&(wbpb->bpb.sectors_in_logical_volume))[0] = *grabp++;
257 	wbpb->ebpb.phys_drive_num = *grabp++;
258 	wbpb->ebpb.reserved = *grabp++;
259 	wbpb->ebpb.ext_signature = *grabp++;
260 	((uchar_t *)&(wbpb->ebpb.volume_id))[3] = *grabp++;
261 	((uchar_t *)&(wbpb->ebpb.volume_id))[2] = *grabp++;
262 	((uchar_t *)&(wbpb->ebpb.volume_id))[1] = *grabp++;
263 	((uchar_t *)&(wbpb->ebpb.volume_id))[0] = *grabp++;
264 
265 	(void) strncpy((char *)wbpb->ebpb.volume_label, (char *)grabp, 11);
266 	grabp += 11;
267 	(void) strncpy((char *)wbpb->ebpb.type, (char *)grabp, 8);
268 }
269 
270 void
271 swap_pack_grab32bpb(bpb_t *wbpb, struct _boot_sector *bsp)
272 {
273 	uchar_t *grabp;
274 
275 	grabp = (uchar_t *)&(bsp->bs_filler[BPB_32_START_INDEX]);
276 
277 	((uchar_t *)&(wbpb->bpb32.big_sectors_per_fat))[3] = *grabp++;
278 	((uchar_t *)&(wbpb->bpb32.big_sectors_per_fat))[2] = *grabp++;
279 	((uchar_t *)&(wbpb->bpb32.big_sectors_per_fat))[1] = *grabp++;
280 	((uchar_t *)&(wbpb->bpb32.big_sectors_per_fat))[0] = *grabp++;
281 	((uchar_t *)&(wbpb->bpb32.ext_flags))[1] = *grabp++;
282 	((uchar_t *)&(wbpb->bpb32.ext_flags))[0] = *grabp++;
283 	wbpb->bpb32.fs_vers_lo = *grabp++;
284 	wbpb->bpb32.fs_vers_hi = *grabp++;
285 	((uchar_t *)&(wbpb->bpb32.root_dir_clust))[3] = *grabp++;
286 	((uchar_t *)&(wbpb->bpb32.root_dir_clust))[2] = *grabp++;
287 	((uchar_t *)&(wbpb->bpb32.root_dir_clust))[1] = *grabp++;
288 	((uchar_t *)&(wbpb->bpb32.root_dir_clust))[0] = *grabp++;
289 	((uchar_t *)&(wbpb->bpb32.fsinfosec))[1] = *grabp++;
290 	((uchar_t *)&(wbpb->bpb32.fsinfosec))[0] = *grabp++;
291 	((uchar_t *)&(wbpb->bpb32.backupboot))[1] = *grabp++;
292 	((uchar_t *)&(wbpb->bpb32.backupboot))[0] = *grabp++;
293 	((uchar_t *)&(wbpb->bpb32.reserved[0]))[1] = *grabp++;
294 	((uchar_t *)&(wbpb->bpb32.reserved[0]))[0] = *grabp++;
295 	((uchar_t *)&(wbpb->bpb32.reserved[1]))[1] = *grabp++;
296 	((uchar_t *)&(wbpb->bpb32.reserved[1]))[0] = *grabp++;
297 	((uchar_t *)&(wbpb->bpb32.reserved[2]))[1] = *grabp++;
298 	((uchar_t *)&(wbpb->bpb32.reserved[2]))[0] = *grabp++;
299 	((uchar_t *)&(wbpb->bpb32.reserved[3]))[1] = *grabp++;
300 	((uchar_t *)&(wbpb->bpb32.reserved[3]))[0] = *grabp++;
301 	((uchar_t *)&(wbpb->bpb32.reserved[4]))[1] = *grabp++;
302 	((uchar_t *)&(wbpb->bpb32.reserved[4]))[0] = *grabp++;
303 	((uchar_t *)&(wbpb->bpb32.reserved[5]))[1] = *grabp++;
304 	((uchar_t *)&(wbpb->bpb32.reserved[5]))[0] = *grabp++;
305 }
306 #endif	/* _BIG_ENDIAN */
307 
308 int
309 yes(void)
310 {
311 	char *affirmative = gettext("yY");
312 	char *a = affirmative;
313 	char input[80];
314 
315 	if (AlwaysYes) {
316 		(void) printf("y\n");
317 		return (1);
318 	} else if (AlwaysNo) {
319 		(void) printf("n\n");
320 		return (0);
321 	}
322 	if (fgets(input, sizeof (input), stdin) == NULL) {
323 		AlwaysNo = 1;
324 		(void) printf("n\n");
325 		return (0);
326 	}
327 	while (*a) {
328 		if (input[0] == (int)*a)
329 			break;
330 		a++;
331 	}
332 	return ((int)*a);
333 }
334 
335 char *
336 stat_actual_disk(char *diskname, struct stat *info, char **suffix)
337 {
338 	char *actualdisk;
339 
340 	if (stat(diskname, info)) {
341 		/*
342 		 *  Device named on command line doesn't exist.  That
343 		 *  probably means there is a partition-specifying
344 		 *  suffix attached to the actual disk name.
345 		 */
346 		if ((actualdisk = strdup(diskname)) == NULL) {
347 			(void) fprintf(stderr,
348 			    gettext("Out of memory for disk name.\n"));
349 			exit(2);
350 		}
351 		if ((*suffix = strchr(actualdisk, ':')) != NULL) {
352 			**suffix = '\0';
353 			(*suffix)++;
354 		}
355 
356 		if (stat(actualdisk, info)) {
357 			perror(actualdisk);
358 			exit(2);
359 		}
360 	} else {
361 		if ((actualdisk = strdup(diskname)) == NULL) {
362 			(void) fprintf(stderr,
363 			    gettext("Out of memory for disk name.\n"));
364 			exit(2);
365 		}
366 	}
367 
368 	return (actualdisk);
369 }
370 
371 extern void usage(void);
372 
373 void
374 bad_arg(char *option)
375 {
376 	(void) fprintf(stderr,
377 	    gettext("Unrecognized option -o %s.\n"), option);
378 	usage();
379 	exit(2);
380 }
381 
382 void
383 missing_arg(char *option)
384 {
385 	(void) fprintf(stderr,
386 	    gettext("Option %s requires a value.\n"), option);
387 	usage();
388 	exit(3);
389 }
390 
391 static int
392 parse_drvnum(char *pn)
393 {
394 	int drvnum;
395 
396 	/*
397 	 * Determine logical drive to seek after.
398 	 */
399 	if ((strlen(pn) == 1) && ((*pn >= 'c') && (*pn <= 'z'))) {
400 		drvnum = *pn - 'c' + 1;
401 	} else if ((*pn >= '0') && (*pn <= '9')) {
402 		char *d;
403 		int v = 0;
404 
405 		d = pn;
406 		while ((*d != '\0') && (*d >= '0') && (*d <= '9')) {
407 			v *= 10;
408 			v += *d - '0';
409 			d++;
410 		}
411 		if ((*d != '\0') || (v > 24)) {
412 			(void) fprintf(stderr,
413 			    gettext("%s: bogus logical drive specification.\n"),
414 			    pn);
415 			return (-1);
416 		}
417 		drvnum = v;
418 	} else if (strcmp(pn, "boot") == 0) {
419 		drvnum = 99;
420 	} else {
421 		(void) fprintf(stderr,
422 		    gettext("%s: bogus logical drive specification.\n"), pn);
423 		return (-1);
424 	}
425 
426 	return (drvnum);
427 }
428 
429 /*
430  * isDosDrive()
431  *	Boolean function.  Give it the systid field for an fdisk partition
432  *	and it decides if that's a systid that describes a DOS drive.  We
433  *	use systid values defined in sys/dktp/fdisk.h.
434  */
435 static int
436 isDosDrive(uchar_t checkMe)
437 {
438 	return ((checkMe == DOSOS12) || (checkMe == DOSOS16) ||
439 	    (checkMe == DOSHUGE) || (checkMe == FDISK_WINDOWS) ||
440 	    (checkMe == FDISK_EXT_WIN) || (checkMe == FDISK_FAT95) ||
441 	    (checkMe == DIAGPART));
442 }
443 
444 /*
445  * isDosExtended()
446  *	Boolean function.  Give it the systid field for an fdisk partition
447  *	and it decides if that's a systid that describes an extended DOS
448  *	partition.
449  */
450 static int
451 isDosExtended(uchar_t checkMe)
452 {
453 	return ((checkMe == EXTDOS) || (checkMe == FDISK_EXTLBA));
454 }
455 
456 /*
457  * isBootPart()
458  *	Boolean function.  Give it the systid field for an fdisk partition
459  *	and it decides if that's a systid that describes a Solaris boot
460  *	partition.
461  */
462 static int
463 isBootPart(uchar_t checkMe)
464 {
465 	return (checkMe == X86BOOT);
466 }
467 
468 off64_t
469 findPartitionOffset(int fd, char *ldrive)
470 {
471 	struct ipart part[FD_NUMPART];
472 	struct mboot extmboot;
473 	struct mboot mb;
474 	diskaddr_t xstartsect;
475 	off64_t nextseek = 0;
476 	off64_t lastseek = 0;
477 	off64_t found = 0;
478 	off64_t error = -1;
479 	int logicalDriveCount = 0;
480 	int extendedPart = -1;
481 	int primaryPart = -1;
482 	int bootPart = -1;
483 	uint32_t xnumsect = 0;
484 	int drvnum;
485 	int driveIndex;
486 	int i;
487 	/*
488 	 * Count of drives in the current extended partition's
489 	 * FDISK table, and indexes of the drives themselves.
490 	 */
491 	int extndDrives[FD_NUMPART];
492 	int numDrives = 0;
493 	/*
494 	 * Count of drives (beyond primary) in master boot record's
495 	 * FDISK table, and indexes of the drives themselves.
496 	 */
497 	int extraDrives[FD_NUMPART];
498 	int numExtraDrives = 0;
499 
500 	if ((drvnum = parse_drvnum(ldrive)) < 0)
501 		return (error);
502 
503 	if (read(fd, &mb, sizeof (mb)) != sizeof (mb)) {
504 		(void) fprintf(stderr,
505 		    gettext("Couldn't read a Master Boot Record\n"));
506 		return (error);
507 	}
508 
509 	if (ltohs(mb.signature) != BOOTSECSIG) {
510 		(void) fprintf(stderr,
511 		    gettext("Bad signature on master boot record (%x)\n"),
512 		    ltohs(mb.signature));
513 		return (error);
514 	}
515 
516 	/*
517 	 * Copy partition table into memory
518 	 */
519 	(void) memcpy(part, mb.parts, sizeof (part));
520 
521 	/*
522 	 * Get a summary of what is in the Master FDISK table.
523 	 * Normally we expect to find one partition marked as a DOS drive.
524 	 * This partition is the one Windows calls the primary dos partition.
525 	 * If the machine has any logical drives then we also expect
526 	 * to find a partition marked as an extended DOS partition.
527 	 *
528 	 * Sometimes we'll find multiple partitions marked as DOS drives.
529 	 * The Solaris fdisk program allows these partitions
530 	 * to be created, but Windows fdisk no longer does.  We still need
531 	 * to support these, though, since Windows does.  We also need to fix
532 	 * our fdisk to behave like the Windows version.
533 	 *
534 	 * It turns out that some off-the-shelf media have *only* an
535 	 * Extended partition, so we need to deal with that case as
536 	 * well.
537 	 *
538 	 * Only a single (the first) Extended or Boot Partition will
539 	 * be recognized.  Any others will be ignored.
540 	 */
541 	for (i = 0; i < FD_NUMPART; i++) {
542 		if (isDosDrive(part[i].systid)) {
543 			if (primaryPart < 0) {
544 				logicalDriveCount++;
545 				primaryPart = i;
546 			} else {
547 				extraDrives[numExtraDrives++] = i;
548 			}
549 			continue;
550 		}
551 		if ((extendedPart < 0) && isDosExtended(part[i].systid)) {
552 			extendedPart = i;
553 			continue;
554 		}
555 		if ((bootPart < 0) && isBootPart(part[i].systid)) {
556 			bootPart = i;
557 			continue;
558 		}
559 	}
560 
561 	if (drvnum == BOOT_PARTITION_DRIVE) {
562 		if (bootPart < 0) {
563 			(void) fprintf(stderr,
564 			    gettext("No boot partition found on drive\n"));
565 			return (error);
566 		}
567 		found = ltohi(part[bootPart].relsect) * BPSEC;
568 		return (found);
569 	}
570 
571 	if (drvnum == PRIMARY_DOS_DRIVE && primaryPart >= 0) {
572 		found = ltohi(part[primaryPart].relsect) * BPSEC;
573 		return (found);
574 	}
575 
576 	/*
577 	 * We are not looking for the C: drive (or there was no primary
578 	 * drive found), so we had better have an extended partition or
579 	 * extra drives in the Master FDISK table.
580 	 */
581 	if ((extendedPart < 0) && (numExtraDrives == 0)) {
582 		(void) fprintf(stderr,
583 		    gettext("No such logical drive "
584 		    "(missing extended partition entry)\n"));
585 		return (error);
586 	}
587 
588 	if (extendedPart >= 0) {
589 		nextseek = xstartsect = ltohi(part[extendedPart].relsect);
590 		xnumsect = ltohi(part[extendedPart].numsect);
591 		do {
592 			/*
593 			 *  If the seek would not cause us to change
594 			 *  position on the drive, then we're out of
595 			 *  extended partitions to examine.
596 			 */
597 			if (nextseek == lastseek)
598 				break;
599 			logicalDriveCount += numDrives;
600 			/*
601 			 *  Seek the next extended partition, and find
602 			 *  logical drives within it.
603 			 */
604 			if (lseek64(fd, nextseek * BPSEC, SEEK_SET) < 0 ||
605 			    read(fd, &extmboot, sizeof (extmboot)) !=
606 			    sizeof (extmboot)) {
607 				perror(gettext("Unable to read extended "
608 				    "partition record"));
609 				return (error);
610 			}
611 			(void) memcpy(part, extmboot.parts, sizeof (part));
612 			lastseek = nextseek;
613 			if (ltohs(extmboot.signature) != MBB_MAGIC) {
614 				(void) fprintf(stderr,
615 				    gettext("Bad signature on "
616 				    "extended partition\n"));
617 				return (error);
618 			}
619 			/*
620 			 *  Count up drives, and track where the next
621 			 *  extended partition is in case we need it.  We
622 			 *  are expecting only one extended partition.  If
623 			 *  there is more than one we'll only go to the
624 			 *  first one we see, but warn about ignoring.
625 			 */
626 			numDrives = 0;
627 			for (i = 0; i < FD_NUMPART; i++) {
628 				if (isDosDrive(part[i].systid)) {
629 					extndDrives[numDrives++] = i;
630 					continue;
631 				} else if (isDosExtended(part[i].systid)) {
632 					if (nextseek != lastseek) {
633 						/*
634 						 * Already found an extended
635 						 * partition in this table.
636 						 */
637 						(void) fprintf(stderr,
638 						    gettext("WARNING: "
639 						    "Ignoring unexpected "
640 						    "additional extended "
641 						    "partition"));
642 						continue;
643 					}
644 					nextseek = xstartsect +
645 					    ltohi(part[i].relsect);
646 					continue;
647 				}
648 			}
649 		} while (drvnum > logicalDriveCount + numDrives);
650 
651 		if (drvnum <= logicalDriveCount + numDrives) {
652 			/*
653 			 * The number of logical drives we've found thus
654 			 * far is enough to get us to the one we were
655 			 * searching for.
656 			 */
657 			driveIndex = logicalDriveCount + numDrives - drvnum;
658 			found =
659 			    ltohi(part[extndDrives[driveIndex]].relsect) +
660 			    lastseek;
661 			if (found > (xstartsect + xnumsect)) {
662 				(void) fprintf(stderr,
663 				    gettext("Logical drive start sector (%d) "
664 				    "is not within the partition!\n"), found);
665 				return (error);
666 			} else {
667 				found *= BPSEC;
668 			}
669 			return (found);
670 		} else {
671 			/*
672 			 * We ran out of extended dos partition
673 			 * drives.  The only hope now is to go
674 			 * back to extra drives defined in the master
675 			 * fdisk table.  But we overwrote that table
676 			 * already, so we must load it in again.
677 			 */
678 			logicalDriveCount += numDrives;
679 			(void) memcpy(part, mb.parts, sizeof (part));
680 		}
681 	}
682 	/*
683 	 *  Still haven't found the drive, is it an extra
684 	 *  drive defined in the main FDISK table?
685 	 */
686 	if (drvnum <= logicalDriveCount + numExtraDrives) {
687 		driveIndex = logicalDriveCount + numExtraDrives - drvnum;
688 		found = ltohi(part[extraDrives[driveIndex]].relsect) * BPSEC;
689 		return (found);
690 	}
691 	return (error);
692 }
693