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Made ntfsfix able to use a backup boot sector larger than 512 bytes 

When the normal boot sector is not usable, ntfsfix tries to use the last
sector as a boot sector replacement. This implies getting the sector size
and reading both full-sized boot sectors.
edge.strict_endians
Jean-Pierre André 2011-03-23 09:46:46 +01:00
parent c6043ec2c9
commit 86ce44ac58
1 changed files with 44 additions and 28 deletions
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72
ntfsprogs/ntfsfix.c
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@ -605,15 +605,16 @@ error_exit :
* Returns 0 if successful
*/
static int rewrite_boot(struct ntfs_device *dev, NTFS_BOOT_SECTOR *bs)
static int rewrite_boot(struct ntfs_device *dev, char *full_bs,
s32 sector_size)
{
s64 bw;
int res;
res = -1;
ntfs_log_info("Rewriting the bootsector\n");
bw = ntfs_pwrite(dev, 0, sizeof(NTFS_BOOT_SECTOR), bs);
if (bw == sizeof(NTFS_BOOT_SECTOR))
bw = ntfs_pwrite(dev, 0, sector_size, full_bs);
if (bw == sector_size)
res = 0;
else {
if (bw != -1)
@ -638,17 +639,19 @@ static int rewrite_boot(struct ntfs_device *dev, NTFS_BOOT_SECTOR *bs)
* Returns 0 if successful
*/
static int try_fix_boot(ntfs_volume *vol, NTFS_BOOT_SECTOR *bs,
s64 read_sector, s64 fix_sectors)
static int try_fix_boot(ntfs_volume *vol, char *full_bs,
s64 read_sector, s64 fix_sectors, s32 sector_size)
{
s64 br;
int res;
s64 got_sectors;
le16 sector_size_le;
NTFS_BOOT_SECTOR *bs;
res = -1;
br = ntfs_pread(vol->dev, read_sector*DEFAULT_SECTOR_SIZE,
sizeof(NTFS_BOOT_SECTOR), bs);
if (br != sizeof(NTFS_BOOT_SECTOR)) {
br = ntfs_pread(vol->dev, read_sector*sector_size,
sector_size, full_bs);
if (br != sector_size) {
if (br != -1)
errno = EINVAL;
if (!br)
@ -656,9 +659,13 @@ static int try_fix_boot(ntfs_volume *vol, NTFS_BOOT_SECTOR *bs,
else
ntfs_log_perror("Error reading alternate bootsector");
} else {
bs = (NTFS_BOOT_SECTOR*)full_bs;
got_sectors = le64_to_cpu(bs->number_of_sectors);
bs->number_of_sectors = cpu_to_le64(fix_sectors);
if (ntfs_boot_sector_is_ntfs(bs)
/* alignment problem on Sparc, even doing memcpy() */
sector_size_le = cpu_to_le16(sector_size);
if (!memcmp(&sector_size_le, &bs->bpb.bytes_per_sector,2)
&& ntfs_boot_sector_is_ntfs(bs)
&& !ntfs_boot_sector_parse(vol, bs)) {
ntfs_log_info("The alternate bootsector is usable\n");
if (fix_sectors != got_sectors)
@ -667,7 +674,8 @@ static int try_fix_boot(ntfs_volume *vol, NTFS_BOOT_SECTOR *bs,
(long long)got_sectors);
/* fix the normal boot sector */
if (!opt.no_action) {
res = rewrite_boot(vol->dev, bs);
res = rewrite_boot(vol->dev, full_bs,
sector_size);
} else
res = 0;
}
@ -692,8 +700,8 @@ static int try_fix_boot(ntfs_volume *vol, NTFS_BOOT_SECTOR *bs,
* Returns 0 if successful
*/
static int try_alternate_boot(ntfs_volume *vol, NTFS_BOOT_SECTOR *bs,
s64 shown_sectors)
static int try_alternate_boot(ntfs_volume *vol, char *full_bs,
s32 sector_size, s64 shown_sectors)
{
s64 actual_sectors;
int res;
@ -703,33 +711,35 @@ static int try_alternate_boot(ntfs_volume *vol, NTFS_BOOT_SECTOR *bs,
/*
* We do not rely on the sector size defined in the
* boot sector, supposed to be corrupt, so we assume the
* sector size is 512 (some ioctl might be be needed to
* get the actual size). This is only used to guess the
* alternate boot sector location and should not damage
* boot sector, supposed to be corrupt, so we try to get
* the actual sector size and defaulting to 512 if failed
* to get. This value is only used to guess the alternate
* boot sector location and it is checked against the
* value found in the sector itself. It should not damage
* anything if wrong.
* Other values might be worth trying (1024, 2048, 4096).
*
* Note : the real last sector is not accounted for here.
*/
actual_sectors = ntfs_device_size_get(vol->dev,DEFAULT_SECTOR_SIZE) - 1;
actual_sectors = ntfs_device_size_get(vol->dev,sector_size) - 1;
/* first try the actual last sector */
if ((actual_sectors > 0)
&& !try_fix_boot(vol,bs,actual_sectors,actual_sectors))
&& !try_fix_boot(vol, full_bs, actual_sectors,
actual_sectors, sector_size))
res = 0;
/* then try the shown last sector, if less than actual */
if (res
&& (shown_sectors > 0)
&& (shown_sectors < actual_sectors)
&& !try_fix_boot(vol,bs,shown_sectors,shown_sectors))
&& !try_fix_boot(vol, full_bs, shown_sectors,
shown_sectors, sector_size))
res = 0;
/* then try reducing the number of sectors to actual value */
if (res
&& (shown_sectors > actual_sectors)
&& !try_fix_boot(vol,bs,0,actual_sectors))
&& !try_fix_boot(vol, full_bs, 0, actual_sectors, sector_size))
res = 0;
return (res);
@ -748,7 +758,9 @@ static int fix_startup(struct ntfs_device *dev, unsigned long flags)
ntfs_volume *vol;
BOOL dev_open;
s64 shown_sectors;
char *full_bs;
NTFS_BOOT_SECTOR *bs;
s32 sector_size;
int res;
int eo;
@ -761,10 +773,6 @@ static int fix_startup(struct ntfs_device *dev, unsigned long flags)
goto error_exit;
}
bs = (NTFS_BOOT_SECTOR*)ntfs_malloc(sizeof(NTFS_BOOT_SECTOR));
if (!bs)
goto error_exit;
/* Allocate the volume structure. */
vol = ntfs_volume_alloc();
if (!vol)
@ -795,9 +803,15 @@ static int fix_startup(struct ntfs_device *dev, unsigned long flags)
/* Attach the device to the volume. */
vol->dev = dev;
sector_size = ntfs_device_sector_size_get(dev);
if (sector_size <= 0)
sector_size = DEFAULT_SECTOR_SIZE;
full_bs = (char*)malloc(sector_size);
if (!full_bs)
goto error_exit;
/* Now read the bootsector. */
br = ntfs_pread(dev, 0, sizeof(NTFS_BOOT_SECTOR), bs);
if (br != sizeof(NTFS_BOOT_SECTOR)) {
br = ntfs_pread(dev, 0, sector_size, full_bs);
if (br != sector_size) {
if (br != -1)
errno = EINVAL;
if (!br)
@ -806,12 +820,14 @@ static int fix_startup(struct ntfs_device *dev, unsigned long flags)
ntfs_log_perror("Error reading bootsector");
goto error_exit;
}
bs = (NTFS_BOOT_SECTOR*)full_bs;
if (!ntfs_boot_sector_is_ntfs(bs)
/* get the bootsector data, only fails when inconsistent */
|| (ntfs_boot_sector_parse(vol, bs) < 0)) {
shown_sectors = le64_to_cpu(bs->number_of_sectors);
/* boot sector is wrong, try the alternate boot sector */
if (try_alternate_boot(vol, bs, shown_sectors)) {
if (try_alternate_boot(vol, full_bs, sector_size,
shown_sectors)) {
errno = EINVAL;
goto error_exit;
}