xref: /dragonfly/usr.sbin/boot0cfg/boot0cfg.c (revision b7367ef6)
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  * $FreeBSD: src/usr.sbin/boot0cfg/boot0cfg.c,v 1.7.2.4 2002/03/16 01:06:51 mikeh Exp $
27  * $DragonFly: src/usr.sbin/boot0cfg/boot0cfg.c,v 1.5 2007/05/20 23:21:37 dillon Exp $
28  */
29 
30 #include <sys/param.h>
31 #include <sys/diskmbr.h>
32 #include <sys/stat.h>
33 
34 #include <err.h>
35 #include <errno.h>
36 #include <fcntl.h>
37 #include <paths.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <unistd.h>
42 
43 #define MBRSIZE         512     /* master boot record size */
44 
45 #define OFF_VERSION	0x1b0	/* offset: version number */
46 #define OFF_OPT		0x1b9	/* offset: default boot option */
47 #define OFF_DRIVE	0x1ba	/* offset: setdrv drive */
48 #define OFF_FLAGS       0x1bb   /* offset: option flags */
49 #define OFF_TICKS       0x1bc   /* offset: clock ticks */
50 #define OFF_PTBL        0x1be   /* offset: partition table */
51 #define OFF_MAGIC       0x1fe   /* offset: magic number */
52 
53 #define cv2(p)  ((p)[0] | (p)[1] << 010)
54 
55 #define mk2(p, x)                               \
56     (p)[0] = (u_int8_t)(x),                     \
57     (p)[1] = (u_int8_t)((x) >> 010)
58 
59 static const struct {
60     const char *tok;
61     int def;
62 } opttbl[] = {
63     {"packet", 0},
64     {"update", 1},
65     {"setdrv", 0}
66 };
67 static const int nopt = sizeof(opttbl) / sizeof(opttbl[0]);
68 
69 static const char fmt0[] = "#   flag     start chs   type"
70     "       end chs       offset         size\n";
71 
72 static const char fmt1[] = "%d   0x%02x   %4u:%3u:%2u   0x%02x"
73     "   %4u:%3u:%2u   %10u   %10u\n";
74 
75 static int read_mbr(const char *, u_int8_t **, int);
76 static void write_mbr(const char *, int, u_int8_t *, int);
77 static void display_mbr(u_int8_t *);
78 static int boot0version(const u_int8_t *);
79 static int boot0bs(const u_int8_t *);
80 static void stropt(const char *, int *, int *);
81 static char *mkrdev(const char *);
82 static int argtoi(const char *, int, int, int);
83 static void usage(void);
84 
85 /*
86  * Boot manager installation/configuration utility.
87  */
88 int
89 main(int argc, char *argv[])
90 {
91     u_int8_t *mbr, *boot0;
92     int boot0_size, mbr_size;
93     const char *bpath, *fpath;
94     char *disk;
95     int B_flag, v_flag, o_flag;
96     int d_arg, m_arg, s_arg, t_arg;
97     int o_and, o_or;
98     int up, c;
99 
100     bpath = "/boot/boot0";
101     fpath = NULL;
102     B_flag = v_flag = o_flag = 0;
103     d_arg = m_arg = s_arg = t_arg = -1;
104     o_and = 0xff;
105     o_or = 0;
106     while ((c = getopt(argc, argv, "Bvb:d:f:m:o:s:t:")) != -1)
107         switch (c) {
108         case 'B':
109             B_flag = 1;
110             break;
111         case 'v':
112             v_flag = 1;
113             break;
114         case 'b':
115             bpath = optarg;
116             break;
117         case 'd':
118             d_arg = argtoi(optarg, 0, 0xff, 'd');
119             break;
120         case 'f':
121             fpath = optarg;
122             break;
123         case 'm':
124             m_arg = argtoi(optarg, 0, 0xf, 'm');
125             break;
126         case 'o':
127             stropt(optarg, &o_and, &o_or);
128             o_flag = 1;
129             break;
130         case 's':
131             s_arg = argtoi(optarg, 1, 5, 's');
132             break;
133         case 't':
134             t_arg = argtoi(optarg, 1, 0xffff, 't');
135             break;
136         default:
137             usage();
138         }
139     argc -= optind;
140     argv += optind;
141     if (argc != 1)
142         usage();
143     disk = mkrdev(*argv);
144     up = B_flag || d_arg != -1 || m_arg != -1 || o_flag || s_arg != -1
145 	|| t_arg != -1;
146 
147     /* open the disk and read in the existing mbr */
148     mbr_size = read_mbr(disk, &mbr, !B_flag);
149 
150     /* save the existing MBR if we are asked to do so */
151     if (fpath)
152 	write_mbr(fpath, O_CREAT | O_TRUNC, mbr, mbr_size);
153 
154     /*
155      * If we are installing the boot loader, read it from disk and copy the
156      * slice table over from the existing MBR.  If not, then point boot0
157      * back at the MBR we just read in.  After this, boot0 is the data to
158      * write back to disk if we are going to do a write.
159      */
160     if (B_flag) {
161 	boot0_size = read_mbr(bpath, &boot0, 1);
162         memcpy(boot0 + OFF_PTBL, mbr + OFF_PTBL,
163 	    sizeof(struct dos_partition) * NDOSPART);
164     } else {
165 	boot0 = mbr;
166 	boot0_size = mbr_size;
167     }
168 
169     /* set the drive */
170     if (d_arg != -1)
171 	boot0[OFF_DRIVE] = d_arg;
172 
173     /* set various flags */
174     if (m_arg != -1) {
175 	boot0[OFF_FLAGS] &= 0xf0;
176 	boot0[OFF_FLAGS] |= m_arg;
177     }
178     if (o_flag) {
179         boot0[OFF_FLAGS] &= o_and;
180         boot0[OFF_FLAGS] |= o_or;
181     }
182 
183     /* set the default boot selection */
184     if (s_arg != -1)
185         boot0[OFF_OPT] = s_arg - 1;
186 
187     /* set the timeout */
188     if (t_arg != -1)
189         mk2(boot0 + OFF_TICKS, t_arg);
190 
191     /* write the MBR back to disk */
192     if (up)
193 	write_mbr(disk, 0, boot0, boot0_size);
194 
195     /* display the MBR */
196     if (v_flag)
197 	display_mbr(boot0);
198 
199     /* clean up */
200     if (mbr != boot0)
201 	free(boot0);
202     free(mbr);
203     free(disk);
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  */
213 static int
214 read_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  */
252 static void
253 write_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  */
268 static void
269 display_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  */
309 static int
310 boot0version(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 *(const 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  */
326 static int
327 boot0bs(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[] = {0xfc, 0xb8, 0x00, 0x09, 0x8e, 0xc0, 0x8e,
332 			     0xd0, 0xbc, 0x00, 0x10 ,0x31 };
333     static u_int8_t id2[] = {'D', 'r', 'i', 'v', 'e', ' '};
334     static struct {
335 	unsigned off;
336 	unsigned len;
337 	u_int8_t *key;
338     } ident[] = {
339         {0x0,   sizeof(id0), id0},
340         {0x0,	sizeof(id1), id1},
341         {0x1b2, sizeof(id2), id2}
342     };
343     unsigned int i;
344     int count = 0;
345 
346     for (i = 0; i < sizeof(ident) / sizeof(ident[0]); i++) {
347         if (memcmp(bs + ident[i].off, ident[i].key, ident[i].len) == 0)
348 	    ++count;
349     }
350     if (count >= 2)
351 	return 1;
352     return 0;
353 };
354 
355 /*
356  * Adjust "and" and "or" masks for a -o option argument.
357  */
358 static void
359 stropt(const char *arg, int *xa, int *xo)
360 {
361     const char *q;
362     char *s, *s1;
363     int inv, i, x;
364 
365     if (!(s = strdup(arg)))
366         err(1, NULL);
367     for (s1 = s; (q = strtok(s1, ",")); s1 = NULL) {
368         if ((inv = !strncmp(q, "no", 2)))
369             q += 2;
370         for (i = 0; i < nopt; i++)
371             if (!strcmp(q, opttbl[i].tok))
372                 break;
373         if (i == nopt)
374             errx(1, "%s: Unknown -o option", q);
375         if (opttbl[i].def)
376             inv ^= 1;
377         x = 1 << (7 - i);
378         if (inv)
379             *xa &= ~x;
380         else
381             *xo |= x;
382     }
383     free(s);
384 }
385 
386 /*
387  * Produce a device path for a "canonical" name, where appropriate.
388  */
389 static char *
390 mkrdev(const char *fname)
391 {
392     char buf[MAXPATHLEN];
393     char *s;
394 
395     if (!strchr(fname, '/')) {
396 	snprintf(buf, sizeof(buf), "%s%s", _PATH_DEV, fname);
397         s = strdup(buf);
398     } else
399         s = strdup(fname);
400 
401     if (s == NULL)
402         errx(1, "No more memory");
403     return s;
404 }
405 
406 /*
407  * Convert and check an option argument.
408  */
409 static int
410 argtoi(const char *arg, int lo, int hi, int opt)
411 {
412     char *s;
413     long x;
414 
415     errno = 0;
416     x = strtol(arg, &s, 0);
417     if (errno || !*arg || *s || x < lo || x > hi)
418         errx(1, "%s: Bad argument to -%c option", arg, opt);
419     return x;
420 }
421 
422 /*
423  * Display usage information.
424  */
425 static void
426 usage(void)
427 {
428     fprintf(stderr, "%s\n%s\n",
429     "usage: boot0cfg [-Bv] [-b boot0] [-d drive] [-f file] [-m mask]",
430     "                [-o options] [-s slice] [-t ticks] disk");
431     exit(1);
432 }
433