xref: /titanic_41/usr/src/cmd/boot/installgrub/installgrub.c (revision 2eeaed14a5e2ed9bd811643ad5bffc3510ca0310)
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 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <libgen.h>
31 #include <malloc.h>
32 #include <string.h>
33 #include <sys/types.h>
34 #include <sys/stat.h>
35 #include <fcntl.h>
36 #include <unistd.h>
37 #include <strings.h>
38 #include <sys/mount.h>
39 #include <sys/mnttab.h>
40 #include <sys/dktp/fdisk.h>
41 #include <sys/dkio.h>
42 #include <sys/vtoc.h>
43 
44 #include <libintl.h>
45 #include <locale.h>
46 #include "message.h"
47 #include <errno.h>
48 
49 #ifndef	TEXT_DOMAIN
50 #define	TEXT_DOMAIN	"SUNW_OST_OSCMD"
51 #endif
52 
53 #define	SECTOR_SIZE	0x200
54 #define	STAGE2_MEMADDR	0x8000	/* loading addr of stage2 */
55 
56 #define	STAGE1_BPB_OFFSET	0x3
57 #define	STAGE1_BPB_SIZE		0x3B
58 #define	STAGE1_BOOT_DRIVE	0x40
59 #define	STAGE1_FORCE_LBA	0x41
60 #define	STAGE1_STAGE2_ADDRESS	0x42
61 #define	STAGE1_STAGE2_SECTOR	0x44
62 #define	STAGE1_STAGE2_SEGMENT	0x48
63 
64 #define	STAGE2_BLOCKLIST	(SECTOR_SIZE - 0x8)
65 #define	STAGE2_INSTALLPART	(SECTOR_SIZE + 0x8)
66 #define	STAGE2_FORCE_LBA	(SECTOR_SIZE + 0x11)
67 #define	STAGE2_VER_STRING	(SECTOR_SIZE + 0x12)
68 #define	STAGE2_BLKOFF		50	/* offset from start of fdisk part */
69 
70 static int nowrite = 0;
71 static int write_mboot = 0;
72 static int force_mboot = 0;
73 static int is_floppy = 0;
74 static int is_bootpar = 0;
75 static int stage2_fd;
76 static int partition, slice = 0xff;
77 static int stage2_first_sector, stage2_second_sector;
78 
79 
80 static char bpb_sect[SECTOR_SIZE];
81 static char boot_sect[SECTOR_SIZE];
82 static char stage1_buffer[SECTOR_SIZE];
83 static char stage2_buffer[2 * SECTOR_SIZE];
84 static int blocklist[SECTOR_SIZE / sizeof (int)];
85 
86 static int open_device(char *);
87 static void read_bpb_sect(int);
88 static void read_boot_sect(char *);
89 static void write_boot_sect(char *);
90 static void read_stage1_stage2(char *, char *);
91 static void modify_and_write_stage1(int);
92 static void modify_and_write_stage2(int);
93 static int get_start_sector(int);
94 static void copy_stage2(int, char *);
95 static char *get_raw_partition(char *);
96 static void usage(char *);
97 
98 extern int read_stage2_blocklist(int, int *);
99 
100 int
101 main(int argc, char *argv[])
102 {
103 	int dev_fd, opt;
104 	char *stage1, *stage2, *device;
105 
106 	(void) setlocale(LC_ALL, "");
107 	(void) textdomain(TEXT_DOMAIN);
108 
109 	while ((opt = getopt(argc, argv, "fmn")) != EOF) {
110 		switch (opt) {
111 		case 'm':
112 			write_mboot = 1;
113 			break;
114 		case 'n':
115 			nowrite = 1;
116 			break;
117 		case 'f':
118 			force_mboot = 1;
119 			break;
120 		default:
121 			/* fall through to process non-optional args */
122 			break;
123 		}
124 	}
125 
126 	/* check arguments */
127 	if (argc != optind + 3) {
128 		usage(argv[0]);
129 	}
130 
131 	if (nowrite) {
132 		(void) fprintf(stdout, DRY_RUN);
133 	}
134 
135 	stage1 = strdup(argv[optind]);
136 	stage2 = strdup(argv[optind + 1]);
137 	device = strdup(argv[optind + 2]);
138 
139 	if (!stage1 || !stage2 || !device) {
140 		usage(argv[0]);
141 	}
142 
143 	/* open and check device type */
144 	dev_fd = open_device(device);
145 
146 	/* read in stage1 and stage2 into buffer */
147 	read_stage1_stage2(stage1, stage2);
148 
149 	/* In the pcfs case, write a fresh stage2 */
150 	if (is_floppy || is_bootpar) {
151 		copy_stage2(dev_fd, device);
152 		read_bpb_sect(dev_fd);
153 	}
154 
155 	/* read in boot sector */
156 	if (!is_floppy)
157 		read_boot_sect(device);
158 
159 	/* modify stage1 based on grub needs */
160 	modify_and_write_stage1(dev_fd);
161 
162 	/* modify stage2 and write to media */
163 	modify_and_write_stage2(dev_fd);
164 
165 	if (!is_floppy && write_mboot)
166 		write_boot_sect(device);
167 	(void) close(dev_fd);
168 
169 	return (0);
170 }
171 
172 static int
173 get_start_sector(int fd)
174 {
175 	static int start_sect = 0;
176 
177 	int i;
178 	struct mboot *mboot;
179 	struct ipart *part;
180 
181 	if (start_sect)
182 		return (start_sect);
183 
184 	mboot = (struct mboot *)boot_sect;
185 	for (i = 0; i < FD_NUMPART; i++) {
186 		part = (struct ipart *)mboot->parts + i;
187 		if (is_bootpar) {
188 			if (part->systid == 0xbe)
189 				break;
190 		}
191 	}
192 
193 	/*
194 	 * If there is no boot partition, find the solaris partition
195 	 */
196 
197 	if (i == FD_NUMPART) {
198 		struct part_info dkpi;
199 
200 		/*
201 		 * Get the solaris partition information from the device
202 		 * and compare the offset of S2 with offset of solaris partition
203 		 * from fdisk partition table.
204 		 */
205 		if (ioctl(fd, DKIOCPARTINFO, &dkpi) < 0) {
206 			(void) fprintf(stderr, PART_FAIL);
207 			exit(-1);
208 		}
209 
210 		for (i = 0; i < FD_NUMPART; i++) {
211 			part = (struct ipart *)mboot->parts + i;
212 
213 			if (part->relsect == 0) {
214 				(void) fprintf(stderr, BAD_PART, i);
215 				exit(-1);
216 			}
217 			if (dkpi.p_start >= part->relsect &&
218 			    dkpi.p_start < (part->relsect + part->numsect)) {
219 				/* Found the partition */
220 				break;
221 			}
222 		}
223 	}
224 
225 	if (i == FD_NUMPART) {
226 		(void) fprintf(stderr, BOOTPAR);
227 		exit(-1);
228 	}
229 
230 	/* get confirmation for -m */
231 	if (write_mboot && !force_mboot) {
232 		(void) fprintf(stdout, MBOOT_PROMPT);
233 		if (getchar() != 'y') {
234 			write_mboot = 0;
235 			(void) fprintf(stdout, MBOOT_NOT_UPDATED);
236 		}
237 	}
238 
239 	start_sect = part->relsect;
240 	if (part->bootid != 128 && write_mboot == 0) {
241 		(void) fprintf(stdout, BOOTPAR_INACTIVE, i + 1);
242 	}
243 
244 	partition = i;
245 	return (start_sect);
246 }
247 
248 static void
249 usage(char *progname)
250 {
251 	(void) fprintf(stderr, USAGE, basename(progname));
252 	exit(-1);
253 }
254 
255 static int
256 open_device(char *device)
257 {
258 	int dev_fd;
259 	struct stat stat;
260 	char *raw_part;
261 
262 	is_floppy = strncmp(device, "/dev/rdsk", strlen("/dev/rdsk")) &&
263 	    strncmp(device, "/dev/dsk", strlen("/dev/dsk"));
264 
265 	/* handle boot partition specification */
266 	if (!is_floppy && strstr(device, "p0:boot")) {
267 		is_bootpar = 1;
268 	}
269 
270 	raw_part = get_raw_partition(device);
271 
272 	if (nowrite)
273 		dev_fd = open(raw_part, O_RDONLY);
274 	else
275 		dev_fd = open(raw_part, O_RDWR);
276 
277 	if (dev_fd == -1 || fstat(dev_fd, &stat) != 0) {
278 		(void) fprintf(stderr, OPEN_FAIL, raw_part);
279 		exit(-1);
280 	}
281 	if (S_ISCHR(stat.st_mode) == 0) {
282 		(void) fprintf(stderr, NOT_RAW_DEVICE, raw_part);
283 		exit(-1);
284 	}
285 
286 	return (dev_fd);
287 }
288 
289 static void
290 read_stage1_stage2(char *stage1, char *stage2)
291 {
292 	int fd;
293 
294 	/* read the stage1 file from filesystem */
295 	fd = open(stage1, O_RDONLY);
296 	if (fd == -1 || read(fd, stage1_buffer, SECTOR_SIZE) != SECTOR_SIZE) {
297 		(void) fprintf(stderr, READ_FAIL_STAGE1, stage1);
298 		exit(-1);
299 	}
300 	(void) close(fd);
301 
302 	/* read first two blocks of stage 2 from filesystem */
303 	stage2_fd = open(stage2, O_RDONLY);
304 	if (stage2_fd == -1 ||
305 	    read(stage2_fd, stage2_buffer, 2 * SECTOR_SIZE)
306 	    != 2 * SECTOR_SIZE) {
307 		(void) fprintf(stderr, READ_FAIL_STAGE2, stage2);
308 		exit(-1);
309 	}
310 	/* leave the stage2 file open for later */
311 }
312 
313 static void
314 read_bpb_sect(int dev_fd)
315 {
316 	if (pread(dev_fd, bpb_sect, SECTOR_SIZE, 0) != SECTOR_SIZE) {
317 		(void) fprintf(stderr, READ_FAIL_BPB);
318 		exit(-1);
319 	}
320 }
321 
322 static void
323 read_boot_sect(char *device)
324 {
325 	static int read_mbr = 0;
326 	int i, fd;
327 	char save[2];
328 
329 	if (read_mbr)
330 		return;
331 	read_mbr = 1;
332 
333 	/* get the whole disk (p0) */
334 	i = strlen(device);
335 	save[0] = device[i - 2];
336 	save[1] = device[i - 1];
337 	device[i - 2] = 'p';
338 	device[i - 1] = '0';
339 
340 	fd = open(device, O_RDONLY);
341 	if (fd == -1 || read(fd, boot_sect, SECTOR_SIZE) != SECTOR_SIZE) {
342 		(void) fprintf(stderr, READ_FAIL_MBR, device);
343 		if (fd == -1)
344 			perror("open");
345 		else
346 			perror("read");
347 		exit(-1);
348 	}
349 	(void) close(fd);
350 	device[i - 2] = save[0];
351 	device[i - 1] = save[1];
352 }
353 
354 static void
355 write_boot_sect(char *device)
356 {
357 	int fd, len;
358 	char *raw, *end;
359 	struct stat stat;
360 
361 	/* make a copy and chop off ":boot" */
362 	raw = strdup(device);
363 	end = strstr(raw, "p0:boot");
364 	if (end)
365 		end[2] = 0;
366 
367 	/* open p0 (whole disk) */
368 	len = strlen(raw);
369 	raw[len - 2] = 'p';
370 	raw[len - 1] = '0';
371 	fd = open(raw, O_WRONLY);
372 	if (fd == -1 || fstat(fd, &stat) != 0) {
373 		(void) fprintf(stderr, OPEN_FAIL, raw);
374 		exit(-1);
375 	}
376 	if (!nowrite &&
377 	    pwrite(fd, stage1_buffer, SECTOR_SIZE, 0) != SECTOR_SIZE) {
378 		(void) fprintf(stderr, WRITE_FAIL_BOOTSEC);
379 		exit(-1);
380 	}
381 	(void) fprintf(stdout, WRITE_MBOOT);
382 	(void) close(fd);
383 }
384 
385 static void
386 modify_and_write_stage1(int dev_fd)
387 {
388 	if (is_floppy) {
389 		stage2_first_sector = blocklist[0];
390 		/* copy bios parameter block (for fat fs) */
391 		bcopy(bpb_sect + STAGE1_BPB_OFFSET,
392 		    stage1_buffer + STAGE1_BPB_OFFSET, STAGE1_BPB_SIZE);
393 	} else if (is_bootpar) {
394 		stage2_first_sector = get_start_sector(dev_fd) + blocklist[0];
395 		/* copy bios parameter block (for fat fs) and MBR */
396 		bcopy(bpb_sect + STAGE1_BPB_OFFSET,
397 		    stage1_buffer + STAGE1_BPB_OFFSET, STAGE1_BPB_SIZE);
398 		bcopy(boot_sect + BOOTSZ, stage1_buffer + BOOTSZ, 512 - BOOTSZ);
399 		*((unsigned char *)(stage1_buffer + STAGE1_FORCE_LBA)) = 1;
400 	} else {
401 		stage2_first_sector = get_start_sector(dev_fd) + STAGE2_BLKOFF;
402 		/* copy MBR to stage1 in case of overwriting MBR sector */
403 		bcopy(boot_sect + BOOTSZ, stage1_buffer + BOOTSZ, 512 - BOOTSZ);
404 		*((unsigned char *)(stage1_buffer + STAGE1_FORCE_LBA)) = 1;
405 	}
406 
407 	/* modify default stage1 file generated by GRUB */
408 	*((ulong_t *)(stage1_buffer + STAGE1_STAGE2_SECTOR))
409 	    = stage2_first_sector;
410 	*((ushort_t *)(stage1_buffer + STAGE1_STAGE2_ADDRESS))
411 	    = STAGE2_MEMADDR;
412 	*((ushort_t *)(stage1_buffer + STAGE1_STAGE2_SEGMENT))
413 	    = STAGE2_MEMADDR >> 4;
414 
415 	/*
416 	 * XXX the default grub distribution also:
417 	 * - Copy the possible MBR/extended part table
418 	 * - Set the boot drive of stage1
419 	 */
420 
421 	/* write stage1/pboot to 1st sector */
422 	if (!nowrite &&
423 	    pwrite(dev_fd, stage1_buffer, SECTOR_SIZE, 0) != SECTOR_SIZE) {
424 		(void) fprintf(stderr, WRITE_FAIL_PBOOT);
425 		exit(-1);
426 	}
427 
428 	if (is_floppy) {
429 		(void) fprintf(stdout, WRITE_BOOTSEC_FLOPPY);
430 	} else {
431 		(void) fprintf(stdout, WRITE_PBOOT,
432 		    partition, get_start_sector(dev_fd));
433 	}
434 }
435 
436 #define	START_BLOCK(pos)	(*(ulong_t *)(pos))
437 #define	NUM_BLOCK(pos)		(*(ushort_t *)((pos) + 4))
438 #define	START_SEG(pos)		(*(ushort_t *)((pos) + 6))
439 
440 static void
441 modify_and_write_stage2(int dev_fd)
442 {
443 	int nrecord;
444 	off_t offset;
445 
446 	if (is_floppy || is_bootpar) {
447 		int i = 0;
448 		uint_t partition_offset;
449 		uint_t install_addr = 0x8200;
450 		uchar_t *pos = (uchar_t *)stage2_buffer + STAGE2_BLOCKLIST;
451 
452 		stage2_first_sector = blocklist[0];
453 
454 		/* figure out the second sector */
455 		if (blocklist[1] > 1) {
456 			blocklist[0]++;
457 			blocklist[1]--;
458 		} else {
459 			i += 2;
460 		}
461 		stage2_second_sector = blocklist[i];
462 
463 		if (is_floppy)
464 			partition_offset = 0;
465 		else	/* solaris boot partition */
466 			partition_offset = get_start_sector(dev_fd);
467 
468 		/* install the blocklist at the end of stage2_buffer */
469 		while (blocklist[i]) {
470 			if (START_BLOCK(pos - 8) != 0 &&
471 			    START_BLOCK(pos - 8) != blocklist[i + 2]) {
472 				(void) fprintf(stderr, PCFS_FRAGMENTED);
473 				exit(-1);
474 			}
475 			START_BLOCK(pos) = blocklist[i] + partition_offset;
476 			START_SEG(pos) = (ushort_t)(install_addr >> 4);
477 			NUM_BLOCK(pos) = blocklist[i + 1];
478 			install_addr += blocklist[i + 1] * SECTOR_SIZE;
479 			pos -= 8;
480 			i += 2;
481 		}
482 
483 	} else {
484 		/*
485 		 * In a solaris partition, stage2 is written to contiguous
486 		 * blocks. So we update the starting block only.
487 		 */
488 		*((ulong_t *)(stage2_buffer + STAGE2_BLOCKLIST)) =
489 		    stage2_first_sector + 1;
490 	}
491 
492 	if (is_floppy) {
493 		/* modify the config file to add (fd0) */
494 		char *config_file = stage2_buffer + STAGE2_VER_STRING;
495 		while (*config_file++)
496 			;
497 		strcpy(config_file, "(fd0)/boot/grub/menu.lst");
498 	} else {
499 		/* force lba and set disk partition */
500 		*((unsigned char *) (stage2_buffer + STAGE2_FORCE_LBA)) = 1;
501 		*((long *)(stage2_buffer + STAGE2_INSTALLPART))
502 		    = (partition << 16) | (slice << 8) | 0xff;
503 	}
504 
505 	/* modification done, now do the writing */
506 	if (is_floppy || is_bootpar) {
507 		/* we rewrite block 0 and 1 and that's it */
508 		if (!nowrite &&
509 		    (pwrite(dev_fd, stage2_buffer, SECTOR_SIZE,
510 		    stage2_first_sector * SECTOR_SIZE) != SECTOR_SIZE ||
511 		    pwrite(dev_fd, stage2_buffer + SECTOR_SIZE, SECTOR_SIZE,
512 		    stage2_second_sector * SECTOR_SIZE) != SECTOR_SIZE)) {
513 			(void) fprintf(stderr, WRITE_FAIL_STAGE2);
514 			exit(-1);
515 		}
516 		(void) fprintf(stdout, WRITE_STAGE2_PCFS);
517 		return;
518 	}
519 
520 	/* for disk, write stage2 starting at STAGE2_BLKOFF sector */
521 	offset = STAGE2_BLKOFF;
522 
523 	/* write the modified first two sectors */
524 	if (!nowrite && pwrite(dev_fd, stage2_buffer, 2 * SECTOR_SIZE,
525 	    offset * SECTOR_SIZE) != 2 * SECTOR_SIZE) {
526 		(void) fprintf(stderr, WRITE_FAIL_STAGE2);
527 		exit(-1);
528 	}
529 
530 	/* write the remaining sectors */
531 	nrecord = 2;
532 	offset += 2;
533 	for (;;) {
534 		int nread, nwrite;
535 		nread = pread(stage2_fd, stage2_buffer, SECTOR_SIZE,
536 		    nrecord * SECTOR_SIZE);
537 		if (nread > 0 && !nowrite)
538 			nwrite = pwrite(dev_fd, stage2_buffer, SECTOR_SIZE,
539 			    offset * SECTOR_SIZE);
540 		else
541 			nwrite = SECTOR_SIZE;
542 		if (nread < 0 || nwrite != SECTOR_SIZE) {
543 			(void) fprintf(stderr, WRITE_FAIL_STAGE2_BLOCKS,
544 			    nread, nwrite);
545 			break;
546 		}
547 		if (nread > 0) {
548 			nrecord ++;
549 			offset ++;
550 		}
551 		if (nread < SECTOR_SIZE)
552 			break;	/* end of file */
553 	}
554 	(void) fprintf(stdout, WRITE_STAGE2_DISK,
555 	    partition, nrecord, STAGE2_BLKOFF, stage2_first_sector);
556 }
557 
558 static char *
559 get_raw_partition(char *device)
560 {
561 	int len;
562 	struct mboot *mboot;
563 	static char *raw = NULL;
564 
565 	if (raw)
566 		return (raw);
567 	raw = strdup(device);
568 
569 	if (is_floppy)
570 		return (raw);
571 
572 	if (is_bootpar) {
573 		int i;
574 		char *end = strstr(raw, "p0:boot");
575 
576 		end[2] = 0;		/* chop off :boot */
577 		read_boot_sect(raw);
578 		mboot = (struct mboot *)boot_sect;
579 		for (i = 0; i < FD_NUMPART; i++) {
580 			struct ipart *part = (struct ipart *)mboot->parts + i;
581 			if (part->systid == 0xbe)	/* solaris boot part */
582 				break;
583 		}
584 
585 		if (i == FD_NUMPART) {
586 			(void) fprintf(stderr, BOOTPAR_NOTFOUND, device);
587 			exit(-1);
588 		}
589 		end[1] = '1' + i;	/* set partition name */
590 		return (raw);
591 	}
592 
593 	/* For disk, remember slice and return whole fdisk partition  */
594 	len = strlen(raw);
595 	if (raw[len - 2] != 's' || raw[len - 1] == '2') {
596 		(void) fprintf(stderr, NOT_ROOT_SLICE);
597 		exit(-1);
598 	}
599 	slice = atoi(&raw[len - 1]);
600 
601 	raw[len - 2] = 's';
602 	raw[len - 1] = '2';
603 	return (raw);
604 }
605 
606 #define	TMP_MNTPT	"/tmp/installgrub_pcfs"
607 static void
608 copy_stage2(int dev_fd, char *device)
609 {
610 	FILE *mntfp;
611 	int i, pcfs_fp;
612 	char buf[SECTOR_SIZE];
613 	char *cp;
614 	struct mnttab mp = {0}, mpref = {0};
615 
616 	/* convert raw to block device name by removing the first 'r' */
617 	(void) strncpy(buf, device, sizeof (buf));
618 	buf[sizeof (buf) - 1] = 0;
619 	cp = strchr(buf, 'r');
620 	if (cp == NULL) {
621 		(void) fprintf(stderr, CONVERT_FAIL, device);
622 		exit(-1);
623 	}
624 	do {
625 		*cp = *(cp + 1);
626 	} while (*(++cp));
627 
628 	/* get the mount point, if any */
629 	mntfp = fopen("/etc/mnttab", "r");
630 	if (mntfp == NULL) {
631 		(void) fprintf(stderr, OPEN_FAIL_FILE, "/etc/mnttab");
632 		exit(-1);
633 	}
634 
635 	mpref.mnt_special = buf;
636 	if (getmntany(mntfp, &mp, &mpref) != 0) {
637 		char cmd[128];
638 
639 		/* not mounted, try remount */
640 		(void) mkdir(TMP_MNTPT, S_IRWXU);
641 		(void) snprintf(cmd, sizeof (cmd), "mount -F pcfs %s %s",
642 		    buf, TMP_MNTPT);
643 		(void) system(cmd);
644 		rewind(mntfp);
645 		bzero(&mp, sizeof (mp));
646 		if (getmntany(mntfp, &mp, &mpref) != 0) {
647 			(void) fprintf(stderr, MOUNT_FAIL, buf);
648 			exit(-1);
649 		}
650 	}
651 
652 	(void) snprintf(buf, sizeof (buf),
653 	    "%s/boot", mp.mnt_mountp);
654 	(void) mkdir(buf, S_IRWXU);
655 	(void) strcat(buf, "/grub");
656 	(void) mkdir(buf, S_IRWXU);
657 
658 	(void) strcat(buf, "/stage2");
659 	pcfs_fp = open(buf, O_WRONLY | O_CREAT, S_IRWXU);
660 	if (pcfs_fp == -1) {
661 		(void) fprintf(stderr, OPEN_FAIL_FILE, buf);
662 		perror("open:");
663 		(void) umount(TMP_MNTPT);
664 		exit(-1);
665 	}
666 
667 	/* write stage2 to pcfs */
668 	for (i = 0; ; i++) {
669 		int nread, nwrite;
670 		nread = pread(stage2_fd, buf, SECTOR_SIZE, i * SECTOR_SIZE);
671 		if (nowrite)
672 			nwrite = nread;
673 		else
674 			nwrite = pwrite(pcfs_fp, buf, nread, i * SECTOR_SIZE);
675 		if (nread < 0 || nwrite != nread) {
676 			(void) fprintf(stderr, WRITE_FAIL_STAGE2_BLOCKS,
677 			    nread, nwrite);
678 			break;
679 		}
680 		if (nread < SECTOR_SIZE)
681 			break;	/* end of file */
682 	}
683 	(void) close(pcfs_fp);
684 	(void) umount(TMP_MNTPT);
685 
686 	/*
687 	 * Now, get the blocklist from the device.
688 	 */
689 	bzero(blocklist, sizeof (blocklist));
690 	if (read_stage2_blocklist(dev_fd, blocklist) != 0)
691 		exit(-1);
692 }
693