boot0cfg.c revision 74668 
1/*
2 * Copyright (c) 1999 Robert Nordier
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
18 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
19 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
20 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
21 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
22 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
23 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
24 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#ifndef lint
28static const char rcsid[] =
29  "$FreeBSD: head/usr.sbin/boot0cfg/boot0cfg.c 74668 2001-03-22 22:55:13Z iedowse $";
30#endif /* not lint */
31
32#include <sys/param.h>
33#include <sys/disklabel.h>
34#include <sys/stat.h>
35
36#include <err.h>
37#include <errno.h>
38#include <fcntl.h>
39#include <paths.h>
40#include <stdio.h>
41#include <stdlib.h>
42#include <string.h>
43#include <unistd.h>
44
45#define MBRSIZE         512     /* master boot record size */
46
47#define OFF_VERSION	0x1b0	/* offset: version number */
48#define OFF_OPT		0x1b9	/* offset: default boot option */
49#define OFF_DRIVE	0x1ba	/* offset: setdrv drive */
50#define OFF_FLAGS       0x1bb   /* offset: option flags */
51#define OFF_TICKS       0x1bc   /* offset: clock ticks */
52#define OFF_PTBL        0x1be   /* offset: partition table */
53#define OFF_MAGIC       0x1fe   /* offset: magic number */
54
55#define cv2(p)  ((p)[0] | (p)[1] << 010)
56
57#define mk2(p, x)                               \
58    (p)[0] = (u_int8_t)(x),                     \
59    (p)[1] = (u_int8_t)((x) >> 010)
60
61static const struct {
62    const char *tok;
63    int def;
64} opttbl[] = {
65    {"packet", 0},
66    {"update", 1},
67    {"setdrv", 0}
68};
69static const int nopt = sizeof(opttbl) / sizeof(opttbl[0]);
70
71static const char fmt0[] = "#   flag     start chs   type"
72    "       end chs       offset         size\n";
73
74static const char fmt1[] = "%d   0x%02x   %4u:%3u:%2u   0x%02x"
75    "   %4u:%3u:%2u   %10u   %10u\n";
76
77static int read_mbr(const char *, u_int8_t **, int);
78static void write_mbr(const char *, int, u_int8_t *, int);
79static void display_mbr(u_int8_t *);
80static int boot0version(const u_int8_t *);
81static int boot0bs(const u_int8_t *);
82static void stropt(const char *, int *, int *);
83static char *mkrdev(const char *);
84static int argtoi(const char *, int, int, int);
85static void usage(void);
86
87/*
88 * Boot manager installation/configuration utility.
89 */
90int
91main(int argc, char *argv[])
92{
93    u_int8_t *mbr, *boot0;
94    int boot0_size, mbr_size;
95    const char *bpath, *fpath, *disk;
96    int B_flag, v_flag, o_flag;
97    int d_arg, m_arg, s_arg, t_arg;
98    int o_and, o_or;
99    int up, c;
100
101    bpath = "/boot/boot0";
102    fpath = NULL;
103    B_flag = v_flag = o_flag = 0;
104    d_arg = m_arg = s_arg = t_arg = -1;
105    o_and = 0xff;
106    o_or = 0;
107    while ((c = getopt(argc, argv, "Bvb:d:f:m:o:s:t:")) != -1)
108        switch (c) {
109        case 'B':
110            B_flag = 1;
111            break;
112        case 'v':
113            v_flag = 1;
114            break;
115        case 'b':
116            bpath = optarg;
117            break;
118        case 'd':
119            d_arg = argtoi(optarg, 0, 0xff, 'd');
120            break;
121        case 'f':
122            fpath = optarg;
123            break;
124        case 'm':
125            m_arg = argtoi(optarg, 0, 0xf, 'm');
126            break;
127        case 'o':
128            stropt(optarg, &o_and, &o_or);
129            o_flag = 1;
130            break;
131        case 's':
132            s_arg = argtoi(optarg, 1, 5, 's');
133            break;
134        case 't':
135            t_arg = argtoi(optarg, 1, 0xffff, 't');
136            break;
137        default:
138            usage();
139        }
140    argc -= optind;
141    argv += optind;
142    if (argc != 1)
143        usage();
144    disk = mkrdev(*argv);
145    up = B_flag || d_arg != -1 || m_arg != -1 || o_flag || s_arg != -1
146	|| t_arg != -1;
147
148    /* open the disk and read in the existing mbr */
149    mbr_size = read_mbr(disk, &mbr, !B_flag);
150
151    /* save the existing MBR if we are asked to do so */
152    if (fpath)
153	write_mbr(fpath, O_CREAT | O_TRUNC, mbr, mbr_size);
154
155    /*
156     * If we are installing the boot loader, read it from disk and copy the
157     * slice table over from the existing MBR.  If not, then point boot0
158     * back at the MBR we just read in.  After this, boot0 is the data to
159     * write back to disk if we are going to do a write.
160     */
161    if (B_flag) {
162	boot0_size = read_mbr(bpath, &boot0, 1);
163        memcpy(boot0 + OFF_PTBL, mbr + OFF_PTBL,
164	    sizeof(struct dos_partition) * NDOSPART);
165    } else {
166	boot0 = mbr;
167	boot0_size = mbr_size;
168    }
169
170    /* set the drive */
171    if (d_arg != -1)
172	boot0[OFF_DRIVE] = d_arg;
173
174    /* set various flags */
175    if (m_arg != -1) {
176	boot0[OFF_FLAGS] &= 0xf0;
177	boot0[OFF_FLAGS] |= m_arg;
178    }
179    if (o_flag) {
180        boot0[OFF_FLAGS] &= o_and;
181        boot0[OFF_FLAGS] |= o_or;
182    }
183
184    /* set the default boot selection */
185    if (s_arg != -1)
186        boot0[OFF_OPT] = s_arg - 1;
187
188    /* set the timeout */
189    if (t_arg != -1)
190        mk2(boot0 + OFF_TICKS, t_arg);
191
192    /* write the MBR back to disk */
193    if (up)
194	write_mbr(disk, 0, boot0, boot0_size);
195
196    /* display the MBR */
197    if (v_flag)
198	display_mbr(boot0);
199
200    /* clean up */
201    if (mbr != boot0)
202	free(boot0);
203    free(mbr);
204
205    return 0;
206}
207
208/*
209 * Read in the MBR of the disk.  If it is boot0, then use the version to
210 * read in all of it if necessary.  Use pointers to return a malloc'd
211 * buffer containing the MBR and then return its size.
212 */
213static int
214read_mbr(const char *disk, u_int8_t **mbr, int check_version)
215{
216    u_int8_t buf[MBRSIZE];
217    int mbr_size, fd;
218    ssize_t n;
219
220    if ((fd = open(disk, O_RDONLY)) == -1)
221        err(1, "%s", disk);
222    if ((n = read(fd, buf, MBRSIZE)) == -1)
223        err(1, "%s", disk);
224    if (n != MBRSIZE)
225        errx(1, "%s: short read", disk);
226    if (cv2(buf + OFF_MAGIC) != 0xaa55)
227        errx(1, "%s: bad magic", disk);
228
229    if (!boot0bs(buf)) {
230	if (check_version)
231	    errx(1, "%s: unknown or incompatible boot code", disk);
232    } else if (boot0version(buf) == 0x101) {
233	mbr_size = 1024;
234	if ((*mbr = malloc(mbr_size)) == NULL)
235	    errx(1, "%s: unable to allocate read buffer", disk);
236	if (lseek(fd, 0, SEEK_SET) == -1 ||
237	    (n = read(fd, *mbr, mbr_size)) == -1)
238	    err(1, "%s", disk);
239	if (n != mbr_size)
240	    errx(1, "%s: short read", disk);
241	return (mbr_size);
242    }
243    *mbr = malloc(sizeof(buf));
244    memcpy(*mbr, buf, sizeof(buf));
245
246    return sizeof(buf);
247}
248
249/*
250 * Write out the mbr to the specified file.
251 */
252static void
253write_mbr(const char *fname, int flags, u_int8_t *mbr, int mbr_size)
254{
255    int fd;
256    ssize_t n;
257
258    if ((fd = open(fname, O_WRONLY | flags, 0666)) == -1 ||
259	(n = write(fd, mbr, mbr_size)) == -1 || close(fd))
260	err(1, "%s", fname);
261    if (n != mbr_size)
262	errx(1, "%s: short write", fname);
263}
264
265/*
266 * Outputs an informative dump of the data in the MBR to stdout.
267 */
268static void
269display_mbr(u_int8_t *mbr)
270{
271    struct dos_partition *part;
272    int i, version;
273
274    part = (struct dos_partition *)(mbr + DOSPARTOFF);
275    printf(fmt0);
276    for (i = 0; i < NDOSPART; i++)
277	if (part[i].dp_typ)
278	    printf(fmt1, 1 + i, part[i].dp_flag,
279		part[i].dp_scyl + ((part[i].dp_ssect & 0xc0) << 2),
280		part[i].dp_shd, part[i].dp_ssect & 0x3f, part[i].dp_typ,
281                part[i].dp_ecyl + ((part[i].dp_esect & 0xc0) << 2),
282                part[i].dp_ehd, part[i].dp_esect & 0x3f, part[i].dp_start,
283                part[i].dp_size);
284    printf("\n");
285    version = boot0version(mbr);
286    printf("version=%d.%d  drive=0x%x  mask=0x%x  ticks=%u\noptions=",
287	version >> 8, version & 0xff, mbr[OFF_DRIVE],
288	mbr[OFF_FLAGS] & 0xf, cv2(mbr + OFF_TICKS));
289    for (i = 0; i < nopt; i++) {
290	if (i)
291	    printf(",");
292	if (!(mbr[OFF_FLAGS] & 1 << (7 - i)) ^ opttbl[i].def)
293	    printf("no");
294	printf("%s", opttbl[i].tok);
295    }
296    printf("\n");
297    printf("default_selection=F%d (", mbr[OFF_OPT] + 1);
298    if (mbr[OFF_OPT] < 4)
299	printf("Slice %d", mbr[OFF_OPT] + 1);
300    else
301	printf("Drive 1");
302    printf(")\n");
303}
304
305/*
306 * Return the boot0 version with the minor revision in the low byte, and
307 * the major revision in the next higher byte.
308 */
309static int
310boot0version(const u_int8_t *bs)
311{
312    static u_int8_t idold[] = {0xfe, 0x45, 0xf2, 0xe9, 0x00, 0x8a};
313
314    /* Check for old version, and return 0x100 if found. */
315    if (memcmp(bs + 0x1c, idold, sizeof(idold)) == 0)
316        return 0x100;
317
318    /* We have a newer boot0, so extract the version number and return it. */
319    return *(int *)(bs + OFF_VERSION) & 0xffff;
320}
321
322/*
323 * Decide if we have valid boot0 boot code by looking for
324 * characteristic byte sequences at fixed offsets.
325 */
326static int
327boot0bs(const u_int8_t *bs)
328{
329    static u_int8_t id0[] = {0xfc, 0x31, 0xc0, 0x8e, 0xc0, 0x8e, 0xd8,
330			     0x8e, 0xd0, 0xbc, 0x00, 0x7c };
331    static u_int8_t id1[] = {'D', 'r', 'i', 'v', 'e', ' '};
332    static struct {
333	unsigned off;
334	unsigned len;
335	u_int8_t *key;
336    } ident[2] = {
337        {0x0,   sizeof(id0), id0},
338        {0x1b2, sizeof(id1), id1}
339    };
340    int i;
341
342    for (i = 0; i < sizeof(ident) / sizeof(ident[0]); i++)
343        if (memcmp(bs + ident[i].off, ident[i].key, ident[i].len))
344	    return 0;
345    return 1;
346};
347
348/*
349 * Adjust "and" and "or" masks for a -o option argument.
350 */
351static void
352stropt(const char *arg, int *xa, int *xo)
353{
354    const char *q;
355    char *s, *s1;
356    int inv, i, x;
357
358    if (!(s = strdup(arg)))
359        err(1, NULL);
360    for (s1 = s; (q = strtok(s1, ",")); s1 = NULL) {
361        if ((inv = !strncmp(q, "no", 2)))
362            q += 2;
363        for (i = 0; i < nopt; i++)
364            if (!strcmp(q, opttbl[i].tok))
365                break;
366        if (i == nopt)
367            errx(1, "%s: Unknown -o option", q);
368        if (opttbl[i].def)
369            inv ^= 1;
370        x = 1 << (7 - i);
371        if (inv)
372            *xa &= ~x;
373        else
374            *xo |= x;
375    }
376    free(s);
377}
378
379/*
380 * Produce a device path for a "canonical" name, where appropriate.
381 */
382static char *
383mkrdev(const char *fname)
384{
385    char buf[MAXPATHLEN];
386    char *s;
387
388    s = (char *)fname;
389    if (!strchr(fname, '/')) {
390	snprintf(buf, sizeof(buf), "%s%s", _PATH_DEV, fname);
391        if (!(s = strdup(buf)))
392            err(1, NULL);
393    }
394    return s;
395}
396
397/*
398 * Convert and check an option argument.
399 */
400static int
401argtoi(const char *arg, int lo, int hi, int opt)
402{
403    char *s;
404    long x;
405
406    errno = 0;
407    x = strtol(arg, &s, 0);
408    if (errno || !*arg || *s || x < lo || x > hi)
409        errx(1, "%s: Bad argument to -%c option", arg, opt);
410    return x;
411}
412
413/*
414 * Display usage information.
415 */
416static void
417usage(void)
418{
419    fprintf(stderr, "%s\n%s\n",
420    "usage: boot0cfg [-Bv] [-b boot0] [-d drive] [-f file] [-m mask]",
421    "                [-o options] [-s slice] [-t ticks] disk");
422    exit(1);
423}
424