boot0cfg: check result of malloc in read_mbr()
[dragonfly.git] / usr.sbin / boot0cfg / boot0cfg.c
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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.
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25 *
26 * $FreeBSD: src/usr.sbin/boot0cfg/boot0cfg.c,v 1.7.2.4 2002/03/16 01:06:51 mikeh Exp $
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27 */
28
984263bc 29#include <sys/param.h>
6af3b87d 30#include <sys/diskmbr.h>
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31#include <sys/stat.h>
32
33#include <err.h>
34#include <errno.h>
35#include <fcntl.h>
36#include <paths.h>
37#include <stdio.h>
38#include <stdlib.h>
39#include <string.h>
40#include <unistd.h>
41
42#define MBRSIZE 512 /* master boot record size */
43
44#define OFF_VERSION 0x1b0 /* offset: version number */
45#define OFF_OPT 0x1b9 /* offset: default boot option */
46#define OFF_DRIVE 0x1ba /* offset: setdrv drive */
47#define OFF_FLAGS 0x1bb /* offset: option flags */
48#define OFF_TICKS 0x1bc /* offset: clock ticks */
49#define OFF_PTBL 0x1be /* offset: partition table */
50#define OFF_MAGIC 0x1fe /* offset: magic number */
51
52#define cv2(p) ((p)[0] | (p)[1] << 010)
53
54#define mk2(p, x) \
55 (p)[0] = (u_int8_t)(x), \
56 (p)[1] = (u_int8_t)((x) >> 010)
57
58static const struct {
59 const char *tok;
60 int def;
61} opttbl[] = {
62 {"packet", 0},
63 {"update", 1},
64 {"setdrv", 0}
65};
66static const int nopt = sizeof(opttbl) / sizeof(opttbl[0]);
67
68static const char fmt0[] = "# flag start chs type"
69 " end chs offset size\n";
70
71static const char fmt1[] = "%d 0x%02x %4u:%3u:%2u 0x%02x"
72 " %4u:%3u:%2u %10u %10u\n";
73
74static int read_mbr(const char *, u_int8_t **, int);
75static void write_mbr(const char *, int, u_int8_t *, int);
76static void display_mbr(u_int8_t *);
77static int boot0version(const u_int8_t *);
78static int boot0bs(const u_int8_t *);
79static void stropt(const char *, int *, int *);
80static char *mkrdev(const char *);
81static int argtoi(const char *, int, int, int);
82static void usage(void);
83
84/*
85 * Boot manager installation/configuration utility.
86 */
87int
88main(int argc, char *argv[])
89{
90 u_int8_t *mbr, *boot0;
91 int boot0_size, mbr_size;
92 const char *bpath, *fpath;
93 char *disk;
94 int B_flag, v_flag, o_flag;
95 int d_arg, m_arg, s_arg, t_arg;
96 int o_and, o_or;
97 int up, c;
98
99 bpath = "/boot/boot0";
100 fpath = NULL;
101 B_flag = v_flag = o_flag = 0;
102 d_arg = m_arg = s_arg = t_arg = -1;
103 o_and = 0xff;
104 o_or = 0;
105 while ((c = getopt(argc, argv, "Bvb:d:f:m:o:s:t:")) != -1)
106 switch (c) {
107 case 'B':
108 B_flag = 1;
109 break;
110 case 'v':
111 v_flag = 1;
112 break;
113 case 'b':
114 bpath = optarg;
115 break;
116 case 'd':
117 d_arg = argtoi(optarg, 0, 0xff, 'd');
118 break;
119 case 'f':
120 fpath = optarg;
121 break;
122 case 'm':
123 m_arg = argtoi(optarg, 0, 0xf, 'm');
124 break;
125 case 'o':
126 stropt(optarg, &o_and, &o_or);
127 o_flag = 1;
128 break;
129 case 's':
130 s_arg = argtoi(optarg, 1, 5, 's');
131 break;
132 case 't':
133 t_arg = argtoi(optarg, 1, 0xffff, 't');
134 break;
135 default:
136 usage();
137 }
138 argc -= optind;
139 argv += optind;
140 if (argc != 1)
141 usage();
142 disk = mkrdev(*argv);
143 up = B_flag || d_arg != -1 || m_arg != -1 || o_flag || s_arg != -1
144 || t_arg != -1;
145
146 /* open the disk and read in the existing mbr */
147 mbr_size = read_mbr(disk, &mbr, !B_flag);
148
149 /* save the existing MBR if we are asked to do so */
150 if (fpath)
151 write_mbr(fpath, O_CREAT | O_TRUNC, mbr, mbr_size);
152
153 /*
154 * If we are installing the boot loader, read it from disk and copy the
155 * slice table over from the existing MBR. If not, then point boot0
156 * back at the MBR we just read in. After this, boot0 is the data to
157 * write back to disk if we are going to do a write.
158 */
159 if (B_flag) {
160 boot0_size = read_mbr(bpath, &boot0, 1);
161 memcpy(boot0 + OFF_PTBL, mbr + OFF_PTBL,
162 sizeof(struct dos_partition) * NDOSPART);
163 } else {
164 boot0 = mbr;
165 boot0_size = mbr_size;
166 }
167
168 /* set the drive */
169 if (d_arg != -1)
170 boot0[OFF_DRIVE] = d_arg;
171
172 /* set various flags */
173 if (m_arg != -1) {
174 boot0[OFF_FLAGS] &= 0xf0;
175 boot0[OFF_FLAGS] |= m_arg;
176 }
177 if (o_flag) {
178 boot0[OFF_FLAGS] &= o_and;
179 boot0[OFF_FLAGS] |= o_or;
180 }
181
182 /* set the default boot selection */
183 if (s_arg != -1)
184 boot0[OFF_OPT] = s_arg - 1;
185
186 /* set the timeout */
187 if (t_arg != -1)
188 mk2(boot0 + OFF_TICKS, t_arg);
189
190 /* write the MBR back to disk */
191 if (up)
192 write_mbr(disk, 0, boot0, boot0_size);
193
194 /* display the MBR */
195 if (v_flag)
196 display_mbr(boot0);
197
198 /* clean up */
199 if (mbr != boot0)
200 free(boot0);
201 free(mbr);
202 free(disk);
203
204 return 0;
205}
206
207/*
208 * Read in the MBR of the disk. If it is boot0, then use the version to
209 * read in all of it if necessary. Use pointers to return a malloc'd
210 * buffer containing the MBR and then return its size.
211 */
212static int
213read_mbr(const char *disk, u_int8_t **mbr, int check_version)
214{
215 u_int8_t buf[MBRSIZE];
216 int mbr_size, fd;
217 ssize_t n;
218
219 if ((fd = open(disk, O_RDONLY)) == -1)
3a3af6af 220 err(1, "open %s", disk);
984263bc 221 if ((n = read(fd, buf, MBRSIZE)) == -1)
3a3af6af 222 err(1, "read %s", disk);
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223 if (n != MBRSIZE)
224 errx(1, "%s: short read", disk);
225 if (cv2(buf + OFF_MAGIC) != 0xaa55)
226 errx(1, "%s: bad magic", disk);
227
228 if (!boot0bs(buf)) {
229 if (check_version)
230 errx(1, "%s: unknown or incompatible boot code", disk);
231 } else if (boot0version(buf) == 0x101) {
232 mbr_size = 1024;
233 if ((*mbr = malloc(mbr_size)) == NULL)
234 errx(1, "%s: unable to allocate read buffer", disk);
235 if (lseek(fd, 0, SEEK_SET) == -1 ||
236 (n = read(fd, *mbr, mbr_size)) == -1)
237 err(1, "%s", disk);
238 if (n != mbr_size)
239 errx(1, "%s: short read", disk);
5f115e3b 240 close(fd);
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241 return (mbr_size);
242 }
984263bc 243
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244 if ((*mbr = malloc(sizeof(buf))) == NULL)
245 errx(1, "%s: unable to allocate mbr buffer", disk);
246 memcpy(*mbr, buf, sizeof(buf));
247 close(fd);
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248 return sizeof(buf);
249}
250
251/*
252 * Write out the mbr to the specified file.
253 */
254static void
255write_mbr(const char *fname, int flags, u_int8_t *mbr, int mbr_size)
256{
257 int fd;
258 ssize_t n;
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259
260 fd = open(fname, O_WRONLY | flags, 0666);
261 if (fd != -1) {
262 n = write(fd, mbr, mbr_size);
263 close(fd);
264 if (n != mbr_size)
265 errx(1, "%s: short write", fname);
266 return;
267 }
268 if (flags != 0)
984263bc 269 err(1, "%s", fname);
3a3af6af 270 err(1, "write_mbr: %s", fname);
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271}
272
273/*
274 * Outputs an informative dump of the data in the MBR to stdout.
275 */
276static void
277display_mbr(u_int8_t *mbr)
278{
279 struct dos_partition *part;
280 int i, version;
281
282 part = (struct dos_partition *)(mbr + DOSPARTOFF);
283 printf(fmt0);
284 for (i = 0; i < NDOSPART; i++)
285 if (part[i].dp_typ)
286 printf(fmt1, 1 + i, part[i].dp_flag,
287 part[i].dp_scyl + ((part[i].dp_ssect & 0xc0) << 2),
288 part[i].dp_shd, part[i].dp_ssect & 0x3f, part[i].dp_typ,
289 part[i].dp_ecyl + ((part[i].dp_esect & 0xc0) << 2),
290 part[i].dp_ehd, part[i].dp_esect & 0x3f, part[i].dp_start,
291 part[i].dp_size);
292 printf("\n");
293 version = boot0version(mbr);
294 printf("version=%d.%d drive=0x%x mask=0x%x ticks=%u\noptions=",
295 version >> 8, version & 0xff, mbr[OFF_DRIVE],
296 mbr[OFF_FLAGS] & 0xf, cv2(mbr + OFF_TICKS));
297 for (i = 0; i < nopt; i++) {
298 if (i)
299 printf(",");
300 if (!(mbr[OFF_FLAGS] & 1 << (7 - i)) ^ opttbl[i].def)
301 printf("no");
302 printf("%s", opttbl[i].tok);
303 }
304 printf("\n");
305 printf("default_selection=F%d (", mbr[OFF_OPT] + 1);
306 if (mbr[OFF_OPT] < 4)
307 printf("Slice %d", mbr[OFF_OPT] + 1);
308 else
309 printf("Drive 1");
310 printf(")\n");
311}
312
313/*
314 * Return the boot0 version with the minor revision in the low byte, and
315 * the major revision in the next higher byte.
316 */
317static int
318boot0version(const u_int8_t *bs)
319{
320 static u_int8_t idold[] = {0xfe, 0x45, 0xf2, 0xe9, 0x00, 0x8a};
321
322 /* Check for old version, and return 0x100 if found. */
323 if (memcmp(bs + 0x1c, idold, sizeof(idold)) == 0)
324 return 0x100;
325
326 /* We have a newer boot0, so extract the version number and return it. */
327 return *(const int *)(bs + OFF_VERSION) & 0xffff;
328}
329
330/*
331 * Decide if we have valid boot0 boot code by looking for
332 * characteristic byte sequences at fixed offsets.
333 */
334static int
335boot0bs(const u_int8_t *bs)
336{
337 static u_int8_t id0[] = {0xfc, 0x31, 0xc0, 0x8e, 0xc0, 0x8e, 0xd8,
338 0x8e, 0xd0, 0xbc, 0x00, 0x7c };
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339 static u_int8_t id1[] = {0xfc, 0xb8, 0x00, 0x09, 0x8e, 0xc0, 0x8e,
340 0xd0, 0xbc, 0x00, 0x10 ,0x31 };
341 static u_int8_t id2[] = {'D', 'r', 'i', 'v', 'e', ' '};
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342 static struct {
343 unsigned off;
344 unsigned len;
345 u_int8_t *key;
a41b75cb 346 } ident[] = {
984263bc 347 {0x0, sizeof(id0), id0},
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348 {0x0, sizeof(id1), id1},
349 {0x1b2, sizeof(id2), id2}
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350 };
351 unsigned int i;
a41b75cb 352 int count = 0;
984263bc 353
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354 for (i = 0; i < sizeof(ident) / sizeof(ident[0]); i++) {
355 if (memcmp(bs + ident[i].off, ident[i].key, ident[i].len) == 0)
356 ++count;
357 }
358 if (count >= 2)
359 return 1;
360 return 0;
3a3af6af 361}
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362
363/*
364 * Adjust "and" and "or" masks for a -o option argument.
365 */
366static void
367stropt(const char *arg, int *xa, int *xo)
368{
369 const char *q;
370 char *s, *s1;
371 int inv, i, x;
372
373 if (!(s = strdup(arg)))
374 err(1, NULL);
375 for (s1 = s; (q = strtok(s1, ",")); s1 = NULL) {
376 if ((inv = !strncmp(q, "no", 2)))
377 q += 2;
378 for (i = 0; i < nopt; i++)
379 if (!strcmp(q, opttbl[i].tok))
380 break;
381 if (i == nopt)
382 errx(1, "%s: Unknown -o option", q);
383 if (opttbl[i].def)
384 inv ^= 1;
385 x = 1 << (7 - i);
386 if (inv)
387 *xa &= ~x;
388 else
389 *xo |= x;
390 }
391 free(s);
392}
393
394/*
395 * Produce a device path for a "canonical" name, where appropriate.
396 */
397static char *
398mkrdev(const char *fname)
399{
400 char buf[MAXPATHLEN];
401 char *s;
402
403 if (!strchr(fname, '/')) {
404 snprintf(buf, sizeof(buf), "%s%s", _PATH_DEV, fname);
405 s = strdup(buf);
406 } else
407 s = strdup(fname);
408
409 if (s == NULL)
410 errx(1, "No more memory");
411 return s;
412}
413
414/*
415 * Convert and check an option argument.
416 */
417static int
418argtoi(const char *arg, int lo, int hi, int opt)
419{
420 char *s;
421 long x;
422
423 errno = 0;
424 x = strtol(arg, &s, 0);
425 if (errno || !*arg || *s || x < lo || x > hi)
426 errx(1, "%s: Bad argument to -%c option", arg, opt);
427 return x;
428}
429
430/*
431 * Display usage information.
432 */
433static void
434usage(void)
435{
436 fprintf(stderr, "%s\n%s\n",
437 "usage: boot0cfg [-Bv] [-b boot0] [-d drive] [-f file] [-m mask]",
438 " [-o options] [-s slice] [-t ticks] disk");
439 exit(1);
440}