Use symbolic constants from <sys/diskmbr.h> instead of local constants.

Always set the magic sequence when we write, rather than trusting the
previously read boot code to do so.

Use explicit encoding/decoding of little endian disk image.

Remove a comment which was OBE.

Change the test vector for "fdisk -I" to reflect that there is a magic
sequence in the result now.

Add test case for "fdisk" which reads the image back.

At least for the two test-cases this program now gives the same result
on sparc64 as on i386.  The lack of an installed /boot/mbr on sparc64
raises an (un)interesting question.
This commit is contained in:
phk 2003-04-13 21:57:08 +00:00
parent 0c818dea2c
commit 5b83ce0b3a
2 changed files with 23 additions and 15 deletions

View File

@ -32,6 +32,7 @@ static const char rcsid[] =
#include <sys/disk.h>
#include <sys/disklabel.h>
#include <sys/diskmbr.h>
#include <sys/endian.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/mount.h>
@ -79,7 +80,7 @@ struct mboot {
unsigned char padding[2]; /* force the longs to be long aligned */
unsigned char *bootinst; /* boot code */
off_t bootinst_size;
struct dos_partition parts[4];
struct dos_partition parts[NDOSPART];
};
static struct mboot mboot;
@ -87,7 +88,6 @@ static int fd, fdw;
#define ACTIVE 0x80
#define BOOT_MAGIC 0xAA55
static uint dos_cyls;
static uint dos_heads;
@ -501,7 +501,7 @@ init_boot(void)
if ((mboot.bootinst = malloc(mboot.bootinst_size)) == NULL)
errx(1, "unable to allocate boot block buffer");
memset(mboot.bootinst, 0, mboot.bootinst_size);
*(uint16_t *)(void *)&mboot.bootinst[MBRSIGOFF] = BOOT_MAGIC;
le16enc(&mboot.bootinst[DOSMAGICOFFSET], DOSMAGIC);
#endif
}
@ -809,6 +809,8 @@ get_params()
static int
read_s0()
{
int i;
mboot.bootinst_size = secsize;
if (mboot.bootinst != NULL)
free(mboot.bootinst);
@ -821,31 +823,31 @@ read_s0()
warnx("can't read fdisk partition table");
return -1;
}
if (*(uint16_t *)(void *)&mboot.bootinst[MBRSIGOFF] != BOOT_MAGIC) {
if (le16dec(&mboot.bootinst[DOSMAGICOFFSET]) != DOSMAGIC) {
warnx("invalid fdisk partition table found");
/* So should we initialize things */
return -1;
}
memcpy(mboot.parts, &mboot.bootinst[DOSPARTOFF], sizeof(mboot.parts));
for (i = 0; i < NDOSPART; i++)
dos_partition_dec(
&mboot.bootinst[DOSPARTOFF + i * DOSPARTSIZE],
&mboot.parts[i]);
return 0;
}
static int
write_s0()
{
int sector;
int sector, i;
if (iotest) {
print_s0(-1);
return 0;
}
memcpy(&mboot.bootinst[DOSPARTOFF], mboot.parts, sizeof(mboot.parts));
/*
* write enable label sector before write (if necessary),
* disable after writing.
* needed if the disklabel protected area also protects
* sector 0. (e.g. empty disk)
*/
for(i = 0; i < NDOSPART; i++)
dos_partition_enc(&mboot.bootinst[DOSPARTOFF + i * DOSPARTSIZE],
&mboot.parts[i]);
le16enc(&mboot.bootinst[DOSMAGICOFFSET], DOSMAGIC);
for(sector = 0; sector < mboot.bootinst_size / secsize; sector++)
if (write_disk(sector,
&mboot.bootinst[sector * secsize]) == -1) {

View File

@ -16,9 +16,15 @@ dd if=/dev/zero of=tmp count=1 > /dev/null 2>&1
rm tmp
c=`dd if=/dev/${MD} count=1 2>/dev/null | md5`
if [ $c != 509b44919d3921502bd31237c4bb1f75 ] ; then
echo "FAILED: fdisk -I gives bad checksum" 1>&2
if [ $c != ea4277fcccb6a927a1a497a6b15bfb8c ] ; then
echo "FAILED: 'fdisk -I' gives bad checksum ($c)" 1>&2
exit 1
fi
echo "PASSED: fdisk -I"
c=`./fdisk $MD | md5`
if [ $c != 4b126d7ac4c6b2af7ef27ede8ef102ec ] ; then
echo "FAILED: 'fdisk' gives bad checksum ($c)" 1>&2
exit 1
fi
echo "PASSED: fdisk"
exit 0