Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

553 lines (494 sloc) 15.558 kB
/*
* fs/partitions/msdos.c
*
* Code extracted from drivers/block/genhd.c
* Copyright (C) 1991-1998 Linus Torvalds
*
* Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug
* in the early extended-partition checks and added DM partitions
*
* Support for DiskManager v6.0x added by Mark Lord,
* with information provided by OnTrack. This now works for linux fdisk
* and LILO, as well as loadlin and bootln. Note that disks other than
* /dev/hda *must* have a "DOS" type 0x51 partition in the first slot (hda1).
*
* More flexible handling of extended partitions - aeb, 950831
*
* Check partition table on IDE disks for common CHS translations
*
* Re-organised Feb 1998 Russell King
*/
#include <linux/msdos_fs.h>
#include "check.h"
#include "msdos.h"
#include "efi.h"
/*
* Many architectures don't like unaligned accesses, while
* the nr_sects and start_sect partition table entries are
* at a 2 (mod 4) address.
*/
#include <asm/unaligned.h>
#define SYS_IND(p) get_unaligned(&p->sys_ind)
static inline sector_t nr_sects(struct partition *p)
{
return (sector_t)get_unaligned_le32(&p->nr_sects);
}
static inline sector_t start_sect(struct partition *p)
{
return (sector_t)get_unaligned_le32(&p->start_sect);
}
static inline int is_extended_partition(struct partition *p)
{
return (SYS_IND(p) == DOS_EXTENDED_PARTITION ||
SYS_IND(p) == WIN98_EXTENDED_PARTITION ||
SYS_IND(p) == LINUX_EXTENDED_PARTITION);
}
#define MSDOS_LABEL_MAGIC1 0x55
#define MSDOS_LABEL_MAGIC2 0xAA
static inline int
msdos_magic_present(unsigned char *p)
{
return (p[0] == MSDOS_LABEL_MAGIC1 && p[1] == MSDOS_LABEL_MAGIC2);
}
/* Value is EBCDIC 'IBMA' */
#define AIX_LABEL_MAGIC1 0xC9
#define AIX_LABEL_MAGIC2 0xC2
#define AIX_LABEL_MAGIC3 0xD4
#define AIX_LABEL_MAGIC4 0xC1
static int aix_magic_present(struct parsed_partitions *state, unsigned char *p)
{
struct partition *pt = (struct partition *) (p + 0x1be);
Sector sect;
unsigned char *d;
int slot, ret = 0;
if (!(p[0] == AIX_LABEL_MAGIC1 &&
p[1] == AIX_LABEL_MAGIC2 &&
p[2] == AIX_LABEL_MAGIC3 &&
p[3] == AIX_LABEL_MAGIC4))
return 0;
/* Assume the partition table is valid if Linux partitions exists */
for (slot = 1; slot <= 4; slot++, pt++) {
if (pt->sys_ind == LINUX_SWAP_PARTITION ||
pt->sys_ind == LINUX_RAID_PARTITION ||
pt->sys_ind == LINUX_DATA_PARTITION ||
pt->sys_ind == LINUX_LVM_PARTITION ||
is_extended_partition(pt))
return 0;
}
d = read_part_sector(state, 7, &sect);
if (d) {
if (d[0] == '_' && d[1] == 'L' && d[2] == 'V' && d[3] == 'M')
ret = 1;
put_dev_sector(sect);
};
return ret;
}
/*
* Create devices for each logical partition in an extended partition.
* The logical partitions form a linked list, with each entry being
* a partition table with two entries. The first entry
* is the real data partition (with a start relative to the partition
* table start). The second is a pointer to the next logical partition
* (with a start relative to the entire extended partition).
* We do not create a Linux partition for the partition tables, but
* only for the actual data partitions.
*/
static void parse_extended(struct parsed_partitions *state,
sector_t first_sector, sector_t first_size)
{
struct partition *p;
Sector sect;
unsigned char *data;
sector_t this_sector, this_size;
sector_t sector_size = bdev_logical_block_size(state->bdev) / 512;
int loopct = 0; /* number of links followed
without finding a data partition */
int i;
this_sector = first_sector;
this_size = first_size;
while (1) {
if (++loopct > 100)
return;
if (state->next == state->limit)
return;
data = read_part_sector(state, this_sector, &sect);
if (!data)
return;
if (!msdos_magic_present(data + 510))
goto done;
p = (struct partition *) (data + 0x1be);
/*
* Usually, the first entry is the real data partition,
* the 2nd entry is the next extended partition, or empty,
* and the 3rd and 4th entries are unused.
* However, DRDOS sometimes has the extended partition as
* the first entry (when the data partition is empty),
* and OS/2 seems to use all four entries.
*/
/*
* First process the data partition(s)
*/
for (i=0; i<4; i++, p++) {
sector_t offs, size, next;
if (!nr_sects(p) || is_extended_partition(p))
continue;
/* Check the 3rd and 4th entries -
these sometimes contain random garbage */
offs = start_sect(p)*sector_size;
size = nr_sects(p)*sector_size;
next = this_sector + offs;
if (i >= 2) {
if (offs + size > this_size)
continue;
if (next < first_sector)
continue;
if (next + size > first_sector + first_size)
continue;
}
put_partition(state, state->next, next, size);
if (SYS_IND(p) == LINUX_RAID_PARTITION)
state->parts[state->next].flags = ADDPART_FLAG_RAID;
loopct = 0;
if (++state->next == state->limit)
goto done;
}
/*
* Next, process the (first) extended partition, if present.
* (So far, there seems to be no reason to make
* parse_extended() recursive and allow a tree
* of extended partitions.)
* It should be a link to the next logical partition.
*/
p -= 4;
for (i=0; i<4; i++, p++)
if (nr_sects(p) && is_extended_partition(p))
break;
if (i == 4)
goto done; /* nothing left to do */
this_sector = first_sector + start_sect(p) * sector_size;
this_size = nr_sects(p) * sector_size;
put_dev_sector(sect);
}
done:
put_dev_sector(sect);
}
/* james@bpgc.com: Solaris has a nasty indicator: 0x82 which also
indicates linux swap. Be careful before believing this is Solaris. */
static void parse_solaris_x86(struct parsed_partitions *state,
sector_t offset, sector_t size, int origin)
{
#ifdef CONFIG_SOLARIS_X86_PARTITION
Sector sect;
struct solaris_x86_vtoc *v;
int i;
short max_nparts;
v = read_part_sector(state, offset + 1, &sect);
if (!v)
return;
if (le32_to_cpu(v->v_sanity) != SOLARIS_X86_VTOC_SANE) {
put_dev_sector(sect);
return;
}
{
char tmp[1 + BDEVNAME_SIZE + 10 + 11 + 1];
snprintf(tmp, sizeof(tmp), " %s%d: <solaris:", state->name, origin);
strlcat(state->pp_buf, tmp, PAGE_SIZE);
}
if (le32_to_cpu(v->v_version) != 1) {
char tmp[64];
snprintf(tmp, sizeof(tmp), " cannot handle version %d vtoc>\n",
le32_to_cpu(v->v_version));
strlcat(state->pp_buf, tmp, PAGE_SIZE);
put_dev_sector(sect);
return;
}
/* Ensure we can handle previous case of VTOC with 8 entries gracefully */
max_nparts = le16_to_cpu (v->v_nparts) > 8 ? SOLARIS_X86_NUMSLICE : 8;
for (i=0; i<max_nparts && state->next<state->limit; i++) {
struct solaris_x86_slice *s = &v->v_slice[i];
char tmp[3 + 10 + 1 + 1];
if (s->s_size == 0)
continue;
snprintf(tmp, sizeof(tmp), " [s%d]", i);
strlcat(state->pp_buf, tmp, PAGE_SIZE);
/* solaris partitions are relative to current MS-DOS
* one; must add the offset of the current partition */
put_partition(state, state->next++,
le32_to_cpu(s->s_start)+offset,
le32_to_cpu(s->s_size));
}
put_dev_sector(sect);
strlcat(state->pp_buf, " >\n", PAGE_SIZE);
#endif
}
#if defined(CONFIG_BSD_DISKLABEL)
/*
* Create devices for BSD partitions listed in a disklabel, under a
* dos-like partition. See parse_extended() for more information.
*/
static void parse_bsd(struct parsed_partitions *state,
sector_t offset, sector_t size, int origin, char *flavour,
int max_partitions)
{
Sector sect;
struct bsd_disklabel *l;
struct bsd_partition *p;
char tmp[64];
l = read_part_sector(state, offset + 1, &sect);
if (!l)
return;
if (le32_to_cpu(l->d_magic) != BSD_DISKMAGIC) {
put_dev_sector(sect);
return;
}
snprintf(tmp, sizeof(tmp), " %s%d: <%s:", state->name, origin, flavour);
strlcat(state->pp_buf, tmp, PAGE_SIZE);
if (le16_to_cpu(l->d_npartitions) < max_partitions)
max_partitions = le16_to_cpu(l->d_npartitions);
for (p = l->d_partitions; p - l->d_partitions < max_partitions; p++) {
sector_t bsd_start, bsd_size;
if (state->next == state->limit)
break;
if (p->p_fstype == BSD_FS_UNUSED)
continue;
bsd_start = le32_to_cpu(p->p_offset);
bsd_size = le32_to_cpu(p->p_size);
if (offset == bsd_start && size == bsd_size)
/* full parent partition, we have it already */
continue;
if (offset > bsd_start || offset+size < bsd_start+bsd_size) {
strlcat(state->pp_buf, "bad subpartition - ignored\n", PAGE_SIZE);
continue;
}
put_partition(state, state->next++, bsd_start, bsd_size);
}
put_dev_sector(sect);
if (le16_to_cpu(l->d_npartitions) > max_partitions) {
snprintf(tmp, sizeof(tmp), " (ignored %d more)",
le16_to_cpu(l->d_npartitions) - max_partitions);
strlcat(state->pp_buf, tmp, PAGE_SIZE);
}
strlcat(state->pp_buf, " >\n", PAGE_SIZE);
}
#endif
static void parse_freebsd(struct parsed_partitions *state,
sector_t offset, sector_t size, int origin)
{
#ifdef CONFIG_BSD_DISKLABEL
parse_bsd(state, offset, size, origin, "bsd", BSD_MAXPARTITIONS);
#endif
}
static void parse_netbsd(struct parsed_partitions *state,
sector_t offset, sector_t size, int origin)
{
#ifdef CONFIG_BSD_DISKLABEL
parse_bsd(state, offset, size, origin, "netbsd", BSD_MAXPARTITIONS);
#endif
}
static void parse_openbsd(struct parsed_partitions *state,
sector_t offset, sector_t size, int origin)
{
#ifdef CONFIG_BSD_DISKLABEL
parse_bsd(state, offset, size, origin, "openbsd",
OPENBSD_MAXPARTITIONS);
#endif
}
/*
* Create devices for Unixware partitions listed in a disklabel, under a
* dos-like partition. See parse_extended() for more information.
*/
static void parse_unixware(struct parsed_partitions *state,
sector_t offset, sector_t size, int origin)
{
#ifdef CONFIG_UNIXWARE_DISKLABEL
Sector sect;
struct unixware_disklabel *l;
struct unixware_slice *p;
l = read_part_sector(state, offset + 29, &sect);
if (!l)
return;
if (le32_to_cpu(l->d_magic) != UNIXWARE_DISKMAGIC ||
le32_to_cpu(l->vtoc.v_magic) != UNIXWARE_DISKMAGIC2) {
put_dev_sector(sect);
return;
}
{
char tmp[1 + BDEVNAME_SIZE + 10 + 12 + 1];
snprintf(tmp, sizeof(tmp), " %s%d: <unixware:", state->name, origin);
strlcat(state->pp_buf, tmp, PAGE_SIZE);
}
p = &l->vtoc.v_slice[1];
/* I omit the 0th slice as it is the same as whole disk. */
while (p - &l->vtoc.v_slice[0] < UNIXWARE_NUMSLICE) {
if (state->next == state->limit)
break;
if (p->s_label != UNIXWARE_FS_UNUSED)
put_partition(state, state->next++,
le32_to_cpu(p->start_sect),
le32_to_cpu(p->nr_sects));
p++;
}
put_dev_sector(sect);
strlcat(state->pp_buf, " >\n", PAGE_SIZE);
#endif
}
/*
* Minix 2.0.0/2.0.2 subpartition support.
* Anand Krishnamurthy <anandk@wiproge.med.ge.com>
* Rajeev V. Pillai <rajeevvp@yahoo.com>
*/
static void parse_minix(struct parsed_partitions *state,
sector_t offset, sector_t size, int origin)
{
#ifdef CONFIG_MINIX_SUBPARTITION
Sector sect;
unsigned char *data;
struct partition *p;
int i;
data = read_part_sector(state, offset, &sect);
if (!data)
return;
p = (struct partition *)(data + 0x1be);
/* The first sector of a Minix partition can have either
* a secondary MBR describing its subpartitions, or
* the normal boot sector. */
if (msdos_magic_present (data + 510) &&
SYS_IND(p) == MINIX_PARTITION) { /* subpartition table present */
char tmp[1 + BDEVNAME_SIZE + 10 + 9 + 1];
snprintf(tmp, sizeof(tmp), " %s%d: <minix:", state->name, origin);
strlcat(state->pp_buf, tmp, PAGE_SIZE);
for (i = 0; i < MINIX_NR_SUBPARTITIONS; i++, p++) {
if (state->next == state->limit)
break;
/* add each partition in use */
if (SYS_IND(p) == MINIX_PARTITION)
put_partition(state, state->next++,
start_sect(p), nr_sects(p));
}
strlcat(state->pp_buf, " >\n", PAGE_SIZE);
}
put_dev_sector(sect);
#endif /* CONFIG_MINIX_SUBPARTITION */
}
static struct {
unsigned char id;
void (*parse)(struct parsed_partitions *, sector_t, sector_t, int);
} subtypes[] = {
{FREEBSD_PARTITION, parse_freebsd},
{NETBSD_PARTITION, parse_netbsd},
{OPENBSD_PARTITION, parse_openbsd},
{MINIX_PARTITION, parse_minix},
{UNIXWARE_PARTITION, parse_unixware},
{SOLARIS_X86_PARTITION, parse_solaris_x86},
{NEW_SOLARIS_X86_PARTITION, parse_solaris_x86},
{0, NULL},
};
int msdos_partition(struct parsed_partitions *state)
{
sector_t sector_size = bdev_logical_block_size(state->bdev) / 512;
Sector sect;
unsigned char *data;
struct partition *p;
struct fat_boot_sector *fb;
int slot;
data = read_part_sector(state, 0, &sect);
if (!data)
return -1;
if (!msdos_magic_present(data + 510)) {
put_dev_sector(sect);
return 0;
}
if (aix_magic_present(state, data)) {
put_dev_sector(sect);
strlcat(state->pp_buf, " [AIX]", PAGE_SIZE);
return 0;
}
/*
* Now that the 55aa signature is present, this is probably
* either the boot sector of a FAT filesystem or a DOS-type
* partition table. Reject this in case the boot indicator
* is not 0 or 0x80.
*/
p = (struct partition *) (data + 0x1be);
for (slot = 1; slot <= 4; slot++, p++) {
if (p->boot_ind != 0 && p->boot_ind != 0x80) {
/*
* Even without a valid boot inidicator value
* its still possible this is valid FAT filesystem
* without a partition table.
*/
fb = (struct fat_boot_sector *) data;
if (slot == 1 && fb->reserved && fb->fats
&& fat_valid_media(fb->media)) {
strlcat(state->pp_buf, "\n", PAGE_SIZE);
put_dev_sector(sect);
return 1;
} else {
put_dev_sector(sect);
return 0;
}
}
}
#ifdef CONFIG_EFI_PARTITION
p = (struct partition *) (data + 0x1be);
for (slot = 1 ; slot <= 4 ; slot++, p++) {
/* If this is an EFI GPT disk, msdos should ignore it. */
if (SYS_IND(p) == EFI_PMBR_OSTYPE_EFI_GPT) {
put_dev_sector(sect);
return 0;
}
}
#endif
p = (struct partition *) (data + 0x1be);
/*
* Look for partitions in two passes:
* First find the primary and DOS-type extended partitions.
* On the second pass look inside *BSD, Unixware and Solaris partitions.
*/
state->next = 5;
for (slot = 1 ; slot <= 4 ; slot++, p++) {
sector_t start = start_sect(p)*sector_size;
sector_t size = nr_sects(p)*sector_size;
if (!size)
continue;
if (is_extended_partition(p)) {
/*
* prevent someone doing mkfs or mkswap on an
* extended partition, but leave room for LILO
* FIXME: this uses one logical sector for > 512b
* sector, although it may not be enough/proper.
*/
sector_t n = 2;
n = min(size, max(sector_size, n));
put_partition(state, slot, start, n);
strlcat(state->pp_buf, " <", PAGE_SIZE);
parse_extended(state, start, size);
strlcat(state->pp_buf, " >", PAGE_SIZE);
continue;
}
put_partition(state, slot, start, size);
if (SYS_IND(p) == LINUX_RAID_PARTITION)
state->parts[slot].flags = ADDPART_FLAG_RAID;
if (SYS_IND(p) == DM6_PARTITION)
strlcat(state->pp_buf, "[DM]", PAGE_SIZE);
if (SYS_IND(p) == EZD_PARTITION)
strlcat(state->pp_buf, "[EZD]", PAGE_SIZE);
}
strlcat(state->pp_buf, "\n", PAGE_SIZE);
/* second pass - output for each on a separate line */
p = (struct partition *) (0x1be + data);
for (slot = 1 ; slot <= 4 ; slot++, p++) {
unsigned char id = SYS_IND(p);
int n;
if (!nr_sects(p))
continue;
for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++)
;
if (!subtypes[n].parse)
continue;
subtypes[n].parse(state, start_sect(p) * sector_size,
nr_sects(p) * sector_size, slot);
}
put_dev_sector(sect);
return 1;
}
Jump to Line
Something went wrong with that request. Please try again.