summaryrefslogtreecommitdiffstats
path: root/usr.sbin/boot0cfg/boot0cfg.c
blob: dc959c0b13583fc69f9c7023b222a1b9791bb4ea (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
/*
 * Copyright (c) 1999 Robert Nordier
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef lint
static const char rcsid[] =
  "$FreeBSD$";
#endif /* not lint */

#include <sys/param.h>
#include <sys/disklabel.h>
#include <sys/stat.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define MBRSIZE         512     /* master boot record size */

#define OFF_VERSION	0x1b0	/* offset: version number */
#define OFF_OPT		0x1b9	/* offset: default boot option */
#define OFF_DRIVE	0x1ba	/* offset: setdrv drive */
#define OFF_FLAGS       0x1bb   /* offset: option flags */
#define OFF_TICKS       0x1bc   /* offset: clock ticks */
#define OFF_PTBL        0x1be   /* offset: partition table */
#define OFF_MAGIC       0x1fe   /* offset: magic number */

#define cv2(p)  ((p)[0] | (p)[1] << 010)

#define mk2(p, x)                               \
    (p)[0] = (u_int8_t)(x),                     \
    (p)[1] = (u_int8_t)((x) >> 010)

static const struct {
    const char *tok;
    int def;
} opttbl[] = {
    {"packet", 0},
    {"update", 1},
    {"setdrv", 0}
};
static const int nopt = sizeof(opttbl) / sizeof(opttbl[0]);

static const char fmt0[] = "#   flag     start chs   type"
    "       end chs       offset         size\n";

static const char fmt1[] = "%d   0x%02x   %4u:%3u:%2u   0x%02x"
    "   %4u:%3u:%2u   %10u   %10u\n";

static int read_mbr(const char *, u_int8_t **, int);
static void write_mbr(const char *, int, u_int8_t *, int);
static void display_mbr(u_int8_t *);
static int boot0version(const u_int8_t *);
static int boot0bs(const u_int8_t *);
static void stropt(const char *, int *, int *);
static char *mkrdev(const char *);
static int argtoi(const char *, int, int, int);
static void usage(void);

/*
 * Boot manager installation/configuration utility.
 */
int
main(int argc, char *argv[])
{
    u_int8_t *mbr, *boot0;
    int boot0_size, mbr_size;
    const char *bpath, *fpath, *disk;
    int B_flag, v_flag, o_flag;
    int d_arg, m_arg, s_arg, t_arg;
    int o_and, o_or;
    int up, c;

    bpath = "/boot/boot0";
    fpath = NULL;
    B_flag = v_flag = o_flag = 0;
    d_arg = m_arg = s_arg = t_arg = -1;
    o_and = 0xff;
    o_or = 0;
    while ((c = getopt(argc, argv, "Bvb:d:f:m:o:s:t:")) != -1)
        switch (c) {
        case 'B':
            B_flag = 1;
            break;
        case 'v':
            v_flag = 1;
            break;
        case 'b':
            bpath = optarg;
            break;
        case 'd':
            d_arg = argtoi(optarg, 0, 0xff, 'd');
            break;
        case 'f':
            fpath = optarg;
            break;
        case 'm':
            m_arg = argtoi(optarg, 0, 0xf, 'm');
            break;
        case 'o':
            stropt(optarg, &o_and, &o_or);
            o_flag = 1;
            break;
        case 's':
            s_arg = argtoi(optarg, 1, 5, 's');
            break;
        case 't':
            t_arg = argtoi(optarg, 1, 0xffff, 't');
            break;
        default:
            usage();
        }
    argc -= optind;
    argv += optind;
    if (argc != 1)
        usage();
    disk = mkrdev(*argv);
    up = B_flag || d_arg != -1 || m_arg != -1 || o_flag || s_arg != -1
	|| t_arg != -1;

    /* open the disk and read in the existing mbr */
    mbr_size = read_mbr(disk, &mbr, !B_flag);

    /* save the existing MBR if we are asked to do so */
    if (fpath)
	write_mbr(fpath, O_CREAT | O_TRUNC, mbr, mbr_size);

    /*
     * If we are installing the boot loader, read it from disk and copy the
     * slice table over from the existing MBR.  If not, then point boot0
     * back at the MBR we just read in.  After this, boot0 is the data to
     * write back to disk if we are going to do a write.
     */
    if (B_flag) {
	boot0_size = read_mbr(bpath, &boot0, 1);
        memcpy(boot0 + OFF_PTBL, mbr + OFF_PTBL,
	    sizeof(struct dos_partition) * NDOSPART);
    } else {
	boot0 = mbr;
	boot0_size = mbr_size;
    }

    /* set the drive */
    if (d_arg != -1)
	boot0[OFF_DRIVE] = d_arg;

    /* set various flags */
    if (m_arg != -1) {
	boot0[OFF_FLAGS] &= 0xf0;
	boot0[OFF_FLAGS] |= m_arg;
    }
    if (o_flag) {
        boot0[OFF_FLAGS] &= o_and;
        boot0[OFF_FLAGS] |= o_or;
    }

    /* set the default boot selection */
    if (s_arg != -1)
        boot0[OFF_OPT] = s_arg - 1;

    /* set the timeout */
    if (t_arg != -1)
        mk2(boot0 + OFF_TICKS, t_arg);

    /* write the MBR back to disk */
    if (up)
	write_mbr(disk, 0, boot0, boot0_size);

    /* display the MBR */
    if (v_flag)
	display_mbr(boot0);

    /* clean up */
    if (mbr != boot0)
	free(boot0);
    free(mbr);

    return 0;
}

/*
 * Read in the MBR of the disk.  If it is boot0, then use the version to
 * read in all of it if necessary.  Use pointers to return a malloc'd
 * buffer containing the MBR and then return its size.
 */
static int
read_mbr(const char *disk, u_int8_t **mbr, int check_version)
{
    u_int8_t buf[MBRSIZE];
    int mbr_size, fd;
    ssize_t n;

    if ((fd = open(disk, O_RDONLY)) == -1)
        err(1, "%s", disk);
    if ((n = read(fd, buf, MBRSIZE)) == -1)
        err(1, "%s", disk);
    if (n != MBRSIZE)
        errx(1, "%s: short read", disk);
    if (cv2(buf + OFF_MAGIC) != 0xaa55)
        errx(1, "%s: bad magic", disk);

    if (!boot0bs(buf)) {
	if (check_version)
	    errx(1, "%s: unknown or incompatible boot code", disk);
    } else if (boot0version(buf) == 0x101) {
	mbr_size = 1024;
	if ((*mbr = malloc(mbr_size)) == NULL)
	    errx(1, "%s: unable to allocate read buffer", disk);
	if (lseek(fd, 0, SEEK_SET) == -1 ||
	    (n = read(fd, *mbr, mbr_size)) == -1)
	    err(1, "%s", disk);
	if (n != mbr_size)
	    errx(1, "%s: short read", disk);
	return (mbr_size);
    }
    *mbr = malloc(sizeof(buf));
    memcpy(*mbr, buf, sizeof(buf));

    return sizeof(buf);
}

/*
 * Write out the mbr to the specified file.
 */
static void
write_mbr(const char *fname, int flags, u_int8_t *mbr, int mbr_size)
{
    int fd;
    ssize_t n;
    
    if ((fd = open(fname, O_WRONLY | flags, 0666)) == -1 ||
	(n = write(fd, mbr, mbr_size)) == -1 || close(fd))
	err(1, "%s", fname);
    if (n != mbr_size)
	errx(1, "%s: short write", fname);
}

/*
 * Outputs an informative dump of the data in the MBR to stdout.
 */
static void
display_mbr(u_int8_t *mbr)
{
    struct dos_partition *part;
    int i, version;

    part = (struct dos_partition *)(mbr + DOSPARTOFF);
    printf(fmt0);
    for (i = 0; i < NDOSPART; i++)
	if (part[i].dp_typ)
	    printf(fmt1, 1 + i, part[i].dp_flag,
		part[i].dp_scyl + ((part[i].dp_ssect & 0xc0) << 2),
		part[i].dp_shd, part[i].dp_ssect & 0x3f, part[i].dp_typ,
                part[i].dp_ecyl + ((part[i].dp_esect & 0xc0) << 2),
                part[i].dp_ehd, part[i].dp_esect & 0x3f, part[i].dp_start,
                part[i].dp_size);
    printf("\n");
    version = boot0version(mbr);
    printf("version=%d.%d  drive=0x%x  mask=0x%x  ticks=%u\noptions=",
	version >> 8, version & 0xff, mbr[OFF_DRIVE],
	mbr[OFF_FLAGS] & 0xf, cv2(mbr + OFF_TICKS));
    for (i = 0; i < nopt; i++) {
	if (i)
	    printf(",");
	if (!(mbr[OFF_FLAGS] & 1 << (7 - i)) ^ opttbl[i].def)
	    printf("no");
	printf("%s", opttbl[i].tok);
    }
    printf("\n");
    printf("default_selection=F%d (", mbr[OFF_OPT] + 1);
    if (mbr[OFF_OPT] < 4)
	printf("Slice %d", mbr[OFF_OPT] + 1);
    else
	printf("Drive 1");
    printf(")\n");
}

/*
 * Return the boot0 version with the minor revision in the low byte, and
 * the major revision in the next higher byte.
 */
static int
boot0version(const u_int8_t *bs)
{
    static u_int8_t idold[] = {0xfe, 0x45, 0xf2, 0xe9, 0x00, 0x8a};

    /* Check for old version, and return 0x100 if found. */
    if (memcmp(bs + 0x1c, idold, sizeof(idold)) == 0)
        return 0x100;

    /* We have a newer boot0, so extract the version number and return it. */
    return *(int *)(bs + OFF_VERSION) & 0xffff;
}

/*
 * Decide if we have valid boot0 boot code by looking for
 * characteristic byte sequences at fixed offsets.
 */
static int
boot0bs(const u_int8_t *bs)
{
    static u_int8_t id0[] = {0xfc, 0x31, 0xc0, 0x8e, 0xc0, 0x8e, 0xd8,
			     0x8e, 0xd0, 0xbc, 0x00, 0x7c };
    static u_int8_t id1[] = {'D', 'r', 'i', 'v', 'e', ' '};
    static struct {
	unsigned off;
	unsigned len;
	u_int8_t *key;
    } ident[2] = {
        {0x0,   sizeof(id0), id0},
        {0x1b2, sizeof(id1), id1}
    };
    int i;

    for (i = 0; i < sizeof(ident) / sizeof(ident[0]); i++)
        if (memcmp(bs + ident[i].off, ident[i].key, ident[i].len))
	    return 0;
    return 1;
};

/*
 * Adjust "and" and "or" masks for a -o option argument.
 */
static void
stropt(const char *arg, int *xa, int *xo)
{
    const char *q;
    char *s, *s1;
    int inv, i, x;

    if (!(s = strdup(arg)))
        err(1, NULL);
    for (s1 = s; (q = strtok(s1, ",")); s1 = NULL) {
        if ((inv = !strncmp(q, "no", 2)))
            q += 2;
        for (i = 0; i < nopt; i++)
            if (!strcmp(q, opttbl[i].tok))
                break;
        if (i == nopt)
            errx(1, "%s: Unknown -o option", q);
        if (opttbl[i].def)
            inv ^= 1;
        x = 1 << (7 - i);
        if (inv)
            *xa &= ~x;
        else
            *xo |= x;
    }
    free(s);
}

/*
 * Produce a device path for a "canonical" name, where appropriate.
 */
static char *
mkrdev(const char *fname)
{
    char buf[MAXPATHLEN];
    char *s;

    s = (char *)fname;
    if (!strchr(fname, '/')) {
	snprintf(buf, sizeof(buf), "%s%s", _PATH_DEV, fname);
        if (!(s = strdup(buf)))
            err(1, NULL);
    }
    return s;
}

/*
 * Convert and check an option argument.
 */
static int
argtoi(const char *arg, int lo, int hi, int opt)
{
    char *s;
    long x;

    errno = 0;
    x = strtol(arg, &s, 0);
    if (errno || !*arg || *s || x < lo || x > hi)
        errx(1, "%s: Bad argument to -%c option", arg, opt);
    return x;
}

/*
 * Display usage information.
 */
static void
usage(void)
{
    fprintf(stderr, "%s\n%s\n",
    "usage: boot0cfg [-Bv] [-b boot0] [-d drive] [-f file] [-m mask]",
    "                [-o options] [-s slice] [-t ticks] disk");
    exit(1);
}
OpenPOWER on IntegriCloud