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

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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:
Poul-Henning Kamp 2003-04-13 21:57:08 +00:00
parent 50e24eb628
commit 1a03d6d57a
2 changed files with 23 additions and 15 deletions
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28
sbin/fdisk/fdisk.c
View File

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

10
sbin/fdisk/runtest.sh
View File

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