freebsd-skq/usr.sbin/boot0cfg/boot0cfg.c
jhb c882f3a97e - When we save the existing MBR to a file, check to see if the MBR we are
saving is boot0.  If it is, use its version number so that we can grab
  all of boot0 (1024 bytes with version 1.1 for example) when we save it
  to a file via the 'f' option.  Otherwise, we just save the first sector.
- Cleanup this code a bit by splitting some functionality out into separate
  functions.

Suggested by:	Patrick Bihan-Faou <patrick@mindstep.com> (1)
2000-07-13 23:05:05 +00:00

409 lines
11 KiB
C

/*
* 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_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, 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 = t_arg = -1;
o_and = 0xff;
o_or = 0;
while ((c = getopt(argc, argv, "Bvb:d:f:m:o: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 '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 || 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 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");
}
/*
* 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] [-t ticks] disk");
exit(1);
}