[deliverable/linux.git] / block / partitions / msdos.c

/*
 *  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"
#include "aix.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;
}

static void set_info(struct parsed_partitions *state, int slot,
		     u32 disksig)
{
	struct partition_meta_info *info = &state->parts[slot].info;

	snprintf(info->uuid, sizeof(info->uuid), "%08x-%02x", disksig,
		 slot);
	info->volname[0] = 0;
	state->parts[slot].has_info = true;
}

/*
 * 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,
			   u32 disksig)
{
	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);
			set_info(state, state->next, disksig);
			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;
	u32 disksig;

	data = read_part_sector(state, 0, &sect);
	if (!data)
		return -1;

	/*
	 * Note order! (some AIX disks, e.g. unbootable kind,
	 * have no MSDOS 55aa)
	 */
	if (aix_magic_present(state, data)) {
		put_dev_sector(sect);
#ifdef CONFIG_AIX_PARTITION
		return aix_partition(state);
#else
		strlcat(state->pp_buf, " [AIX]", PAGE_SIZE);
		return 0;
#endif
	}

	if (!msdos_magic_present(data + 510)) {
		put_dev_sector(sect);
		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);

	disksig = le32_to_cpup((__le32 *)(data + 0x1b8));

	/*
	 * 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, disksig);
			strlcat(state->pp_buf, " >", PAGE_SIZE);
			continue;
		}
		put_partition(state, slot, start, size);
		set_info(state, slot, disksig);
		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;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* fs/partitions/msdos.c
	3	*
	4	* Code extracted from drivers/block/genhd.c
	5	* Copyright (C) 1991-1998 Linus Torvalds
	6	*
	7	* Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug
	8	* in the early extended-partition checks and added DM partitions
	9	*
	10	* Support for DiskManager v6.0x added by Mark Lord,
	11	* with information provided by OnTrack. This now works for linux fdisk
	12	* and LILO, as well as loadlin and bootln. Note that disks other than
	13	* /dev/hda must have a "DOS" type 0x51 partition in the first slot (hda1).
	14	*
	15	* More flexible handling of extended partitions - aeb, 950831
	16	*
	17	* Check partition table on IDE disks for common CHS translations
	18	*
	19	* Re-organised Feb 1998 Russell King
	20	*/
0607fd02	21	#include <linux/msdos_fs.h>
1da177e4 LT	22
	23	#include "check.h"
	24	#include "msdos.h"
	25	#include "efi.h"
f8f06603	26	#include "aix.h"
1da177e4 LT	27
	28	/*
	29	* Many architectures don't like unaligned accesses, while
	30	* the nr_sects and start_sect partition table entries are
	31	* at a 2 (mod 4) address.
	32	*/
	33	#include <asm/unaligned.h>
	34
3fbf586c	35	#define SYS_IND(p) get_unaligned(&p->sys_ind)
1da177e4	36
3fbf586c DT	37	static inline sector_t nr_sects(struct partition *p)
	38	{
	39	return (sector_t)get_unaligned_le32(&p->nr_sects);
	40	}
	41
	42	static inline sector_t start_sect(struct partition *p)
	43	{
	44	return (sector_t)get_unaligned_le32(&p->start_sect);
	45	}
1da177e4 LT	46
	47	static inline int is_extended_partition(struct partition *p)
	48	{
	49	return (SYS_IND(p) == DOS_EXTENDED_PARTITION \|\|
	50	SYS_IND(p) == WIN98_EXTENDED_PARTITION \|\|
	51	SYS_IND(p) == LINUX_EXTENDED_PARTITION);
	52	}
	53
	54	#define MSDOS_LABEL_MAGIC1 0x55
	55	#define MSDOS_LABEL_MAGIC2 0xAA
	56
	57	static inline int
	58	msdos_magic_present(unsigned char *p)
	59	{
	60	return (p[0] == MSDOS_LABEL_MAGIC1 && p[1] == MSDOS_LABEL_MAGIC2);
	61	}
	62
e1dfa92d OH	63	/* Value is EBCDIC 'IBMA' */
	64	#define AIX_LABEL_MAGIC1 0xC9
	65	#define AIX_LABEL_MAGIC2 0xC2
	66	#define AIX_LABEL_MAGIC3 0xD4
	67	#define AIX_LABEL_MAGIC4 0xC1
1493bf21	68	static int aix_magic_present(struct parsed_partitions state, unsigned char p)
e1dfa92d	69	{
4419d1ac	70	struct partition pt = (struct partition ) (p + 0x1be);
e1dfa92d OH	71	Sector sect;
e1dfa92d OH	72	unsigned char *d;
4419d1ac	73	int slot, ret = 0;
e1dfa92d	74
a470e18f OH	75	if (!(p[0] == AIX_LABEL_MAGIC1 &&
	76	p[1] == AIX_LABEL_MAGIC2 &&
	77	p[2] == AIX_LABEL_MAGIC3 &&
	78	p[3] == AIX_LABEL_MAGIC4))
e1dfa92d	79	return 0;
4419d1ac OH	80	/* Assume the partition table is valid if Linux partitions exists */
	81	for (slot = 1; slot <= 4; slot++, pt++) {
	82	if (pt->sys_ind == LINUX_SWAP_PARTITION \|\|
	83	pt->sys_ind == LINUX_RAID_PARTITION \|\|
	84	pt->sys_ind == LINUX_DATA_PARTITION \|\|
	85	pt->sys_ind == LINUX_LVM_PARTITION \|\|
	86	is_extended_partition(pt))
	87	return 0;
	88	}
1493bf21	89	d = read_part_sector(state, 7, &sect);
e1dfa92d OH	90	if (d) {
	91	if (d[0] == '_' && d[1] == 'L' && d[2] == 'V' && d[3] == 'M')
	92	ret = 1;
	93	put_dev_sector(sect);
1d04f3c6	94	}
e1dfa92d OH	95	return ret;
	96	}
	97
d33b98fc SW	98	static void set_info(struct parsed_partitions *state, int slot,
	99	u32 disksig)
	100	{
	101	struct partition_meta_info *info = &state->parts[slot].info;
	102
	103	snprintf(info->uuid, sizeof(info->uuid), "%08x-%02x", disksig,
	104	slot);
	105	info->volname[0] = 0;
	106	state->parts[slot].has_info = true;
	107	}
	108
1da177e4 LT	109	/*
	110	* Create devices for each logical partition in an extended partition.
	111	* The logical partitions form a linked list, with each entry being
	112	* a partition table with two entries. The first entry
	113	* is the real data partition (with a start relative to the partition
	114	* table start). The second is a pointer to the next logical partition
	115	* (with a start relative to the entire extended partition).
	116	* We do not create a Linux partition for the partition tables, but
	117	* only for the actual data partitions.
	118	*/
	119
1493bf21	120	static void parse_extended(struct parsed_partitions *state,
d33b98fc SW	121	sector_t first_sector, sector_t first_size,
d33b98fc SW	122	u32 disksig)
1da177e4 LT	123	{
	124	struct partition *p;
	125	Sector sect;
	126	unsigned char *data;
3fbf586c	127	sector_t this_sector, this_size;
1493bf21	128	sector_t sector_size = bdev_logical_block_size(state->bdev) / 512;
1da177e4 LT	129	int loopct = 0; /* number of links followed
	130	without finding a data partition */
	131	int i;
	132
	133	this_sector = first_sector;
	134	this_size = first_size;
	135
	136	while (1) {
	137	if (++loopct > 100)
	138	return;
	139	if (state->next == state->limit)
	140	return;
1493bf21	141	data = read_part_sector(state, this_sector, &sect);
1da177e4 LT	142	if (!data)
	143	return;
	144
	145	if (!msdos_magic_present(data + 510))
1d04f3c6	146	goto done;
1da177e4 LT	147
	148	p = (struct partition *) (data + 0x1be);
	149
	150	/*
	151	* Usually, the first entry is the real data partition,
	152	* the 2nd entry is the next extended partition, or empty,
	153	* and the 3rd and 4th entries are unused.
	154	* However, DRDOS sometimes has the extended partition as
	155	* the first entry (when the data partition is empty),
	156	* and OS/2 seems to use all four entries.
	157	*/
	158
1d04f3c6	159	/*
1da177e4 LT	160	* First process the data partition(s)
1da177e4 LT	161	*/
dce14c23	162	for (i = 0; i < 4; i++, p++) {
3fbf586c	163	sector_t offs, size, next;
dce14c23	164
3fbf586c	165	if (!nr_sects(p) \|\| is_extended_partition(p))
1da177e4 LT	166	continue;
	167
	168	/* Check the 3rd and 4th entries -
	169	these sometimes contain random garbage */
3fbf586c DT	170	offs = start_sect(p)*sector_size;
3fbf586c DT	171	size = nr_sects(p)*sector_size;
1da177e4 LT	172	next = this_sector + offs;
	173	if (i >= 2) {
	174	if (offs + size > this_size)
	175	continue;
	176	if (next < first_sector)
	177	continue;
	178	if (next + size > first_sector + first_size)
	179	continue;
	180	}
	181
	182	put_partition(state, state->next, next, size);
d33b98fc	183	set_info(state, state->next, disksig);
1da177e4	184	if (SYS_IND(p) == LINUX_RAID_PARTITION)
d18d7682	185	state->parts[state->next].flags = ADDPART_FLAG_RAID;
1da177e4 LT	186	loopct = 0;
	187	if (++state->next == state->limit)
	188	goto done;
	189	}
	190	/*
	191	* Next, process the (first) extended partition, if present.
	192	* (So far, there seems to be no reason to make
	193	* parse_extended() recursive and allow a tree
	194	* of extended partitions.)
	195	* It should be a link to the next logical partition.
	196	*/
	197	p -= 4;
dce14c23	198	for (i = 0; i < 4; i++, p++)
3fbf586c	199	if (nr_sects(p) && is_extended_partition(p))
1da177e4 LT	200	break;
	201	if (i == 4)
	202	goto done; /* nothing left to do */
	203
3fbf586c DT	204	this_sector = first_sector + start_sect(p) * sector_size;
3fbf586c DT	205	this_size = nr_sects(p) * sector_size;
1da177e4 LT	206	put_dev_sector(sect);
	207	}
	208	done:
	209	put_dev_sector(sect);
	210	}
	211
	212	/* james@bpgc.com: Solaris has a nasty indicator: 0x82 which also
	213	indicates linux swap. Be careful before believing this is Solaris. */
	214
1493bf21 TH	215	static void parse_solaris_x86(struct parsed_partitions *state,
1493bf21 TH	216	sector_t offset, sector_t size, int origin)
1da177e4 LT	217	{
	218	#ifdef CONFIG_SOLARIS_X86_PARTITION
	219	Sector sect;
	220	struct solaris_x86_vtoc *v;
	221	int i;
b84d8796	222	short max_nparts;
1da177e4	223
1493bf21	224	v = read_part_sector(state, offset + 1, &sect);
1da177e4 LT	225	if (!v)
	226	return;
	227	if (le32_to_cpu(v->v_sanity) != SOLARIS_X86_VTOC_SANE) {
	228	put_dev_sector(sect);
	229	return;
	230	}
9c867fbe AD	231	{
	232	char tmp[1 + BDEVNAME_SIZE + 10 + 11 + 1];
	233
	234	snprintf(tmp, sizeof(tmp), " %s%d: <solaris:", state->name, origin);
	235	strlcat(state->pp_buf, tmp, PAGE_SIZE);
	236	}
1da177e4	237	if (le32_to_cpu(v->v_version) != 1) {
9c867fbe AD	238	char tmp[64];
	239
	240	snprintf(tmp, sizeof(tmp), " cannot handle version %d vtoc>\n",
	241	le32_to_cpu(v->v_version));
	242	strlcat(state->pp_buf, tmp, PAGE_SIZE);
1da177e4 LT	243	put_dev_sector(sect);
	244	return;
	245	}
b84d8796	246	/* Ensure we can handle previous case of VTOC with 8 entries gracefully */
dce14c23 FF	247	max_nparts = le16_to_cpu(v->v_nparts) > 8 ? SOLARIS_X86_NUMSLICE : 8;
dce14c23 FF	248	for (i = 0; i < max_nparts && state->next < state->limit; i++) {
1da177e4	249	struct solaris_x86_slice *s = &v->v_slice[i];
9c867fbe AD	250	char tmp[3 + 10 + 1 + 1];
9c867fbe AD	251
1da177e4 LT	252	if (s->s_size == 0)
1da177e4 LT	253	continue;
9c867fbe AD	254	snprintf(tmp, sizeof(tmp), " [s%d]", i);
9c867fbe AD	255	strlcat(state->pp_buf, tmp, PAGE_SIZE);
1da177e4 LT	256	/* solaris partitions are relative to current MS-DOS
	257	* one; must add the offset of the current partition */
	258	put_partition(state, state->next++,
	259	le32_to_cpu(s->s_start)+offset,
	260	le32_to_cpu(s->s_size));
	261	}
	262	put_dev_sector(sect);
9c867fbe	263	strlcat(state->pp_buf, " >\n", PAGE_SIZE);
1da177e4 LT	264	#endif
	265	}
	266
486fd404	267	#if defined(CONFIG_BSD_DISKLABEL)
1d04f3c6	268	/*
1da177e4 LT	269	* Create devices for BSD partitions listed in a disklabel, under a
	270	* dos-like partition. See parse_extended() for more information.
	271	*/
1493bf21 TH	272	static void parse_bsd(struct parsed_partitions *state,
	273	sector_t offset, sector_t size, int origin, char *flavour,
	274	int max_partitions)
1da177e4 LT	275	{
	276	Sector sect;
	277	struct bsd_disklabel *l;
	278	struct bsd_partition *p;
9c867fbe	279	char tmp[64];
1da177e4	280
1493bf21	281	l = read_part_sector(state, offset + 1, &sect);
1da177e4 LT	282	if (!l)
	283	return;
	284	if (le32_to_cpu(l->d_magic) != BSD_DISKMAGIC) {
	285	put_dev_sector(sect);
	286	return;
	287	}
9c867fbe AD	288
	289	snprintf(tmp, sizeof(tmp), " %s%d: <%s:", state->name, origin, flavour);
	290	strlcat(state->pp_buf, tmp, PAGE_SIZE);
1da177e4 LT	291
	292	if (le16_to_cpu(l->d_npartitions) < max_partitions)
	293	max_partitions = le16_to_cpu(l->d_npartitions);
	294	for (p = l->d_partitions; p - l->d_partitions < max_partitions; p++) {
3fbf586c	295	sector_t bsd_start, bsd_size;
1da177e4 LT	296
	297	if (state->next == state->limit)
	298	break;
1d04f3c6	299	if (p->p_fstype == BSD_FS_UNUSED)
1da177e4 LT	300	continue;
	301	bsd_start = le32_to_cpu(p->p_offset);
	302	bsd_size = le32_to_cpu(p->p_size);
	303	if (offset == bsd_start && size == bsd_size)
	304	/* full parent partition, we have it already */
	305	continue;
	306	if (offset > bsd_start \|\| offset+size < bsd_start+bsd_size) {
9c867fbe	307	strlcat(state->pp_buf, "bad subpartition - ignored\n", PAGE_SIZE);
1da177e4 LT	308	continue;
	309	}
	310	put_partition(state, state->next++, bsd_start, bsd_size);
	311	}
	312	put_dev_sector(sect);
9c867fbe AD	313	if (le16_to_cpu(l->d_npartitions) > max_partitions) {
	314	snprintf(tmp, sizeof(tmp), " (ignored %d more)",
	315	le16_to_cpu(l->d_npartitions) - max_partitions);
	316	strlcat(state->pp_buf, tmp, PAGE_SIZE);
	317	}
	318	strlcat(state->pp_buf, " >\n", PAGE_SIZE);
1da177e4 LT	319	}
	320	#endif
	321
1493bf21 TH	322	static void parse_freebsd(struct parsed_partitions *state,
1493bf21 TH	323	sector_t offset, sector_t size, int origin)
1da177e4 LT	324	{
1da177e4 LT	325	#ifdef CONFIG_BSD_DISKLABEL
1493bf21	326	parse_bsd(state, offset, size, origin, "bsd", BSD_MAXPARTITIONS);
1da177e4 LT	327	#endif
	328	}
	329
1493bf21 TH	330	static void parse_netbsd(struct parsed_partitions *state,
1493bf21 TH	331	sector_t offset, sector_t size, int origin)
1da177e4 LT	332	{
1da177e4 LT	333	#ifdef CONFIG_BSD_DISKLABEL
1493bf21	334	parse_bsd(state, offset, size, origin, "netbsd", BSD_MAXPARTITIONS);
1da177e4 LT	335	#endif
	336	}
	337
1493bf21 TH	338	static void parse_openbsd(struct parsed_partitions *state,
1493bf21 TH	339	sector_t offset, sector_t size, int origin)
1da177e4 LT	340	{
1da177e4 LT	341	#ifdef CONFIG_BSD_DISKLABEL
1493bf21 TH	342	parse_bsd(state, offset, size, origin, "openbsd",
1493bf21 TH	343	OPENBSD_MAXPARTITIONS);
1da177e4 LT	344	#endif
	345	}
	346
	347	/*
	348	* Create devices for Unixware partitions listed in a disklabel, under a
	349	* dos-like partition. See parse_extended() for more information.
	350	*/
1493bf21 TH	351	static void parse_unixware(struct parsed_partitions *state,
1493bf21 TH	352	sector_t offset, sector_t size, int origin)
1da177e4 LT	353	{
	354	#ifdef CONFIG_UNIXWARE_DISKLABEL
	355	Sector sect;
	356	struct unixware_disklabel *l;
	357	struct unixware_slice *p;
	358
1493bf21	359	l = read_part_sector(state, offset + 29, &sect);
1da177e4 LT	360	if (!l)
	361	return;
	362	if (le32_to_cpu(l->d_magic) != UNIXWARE_DISKMAGIC \|\|
	363	le32_to_cpu(l->vtoc.v_magic) != UNIXWARE_DISKMAGIC2) {
	364	put_dev_sector(sect);
	365	return;
	366	}
9c867fbe AD	367	{
	368	char tmp[1 + BDEVNAME_SIZE + 10 + 12 + 1];
	369
	370	snprintf(tmp, sizeof(tmp), " %s%d: <unixware:", state->name, origin);
	371	strlcat(state->pp_buf, tmp, PAGE_SIZE);
	372	}
1da177e4 LT	373	p = &l->vtoc.v_slice[1];
	374	/* I omit the 0th slice as it is the same as whole disk. */
	375	while (p - &l->vtoc.v_slice[0] < UNIXWARE_NUMSLICE) {
	376	if (state->next == state->limit)
	377	break;
	378
	379	if (p->s_label != UNIXWARE_FS_UNUSED)
	380	put_partition(state, state->next++,
3fbf586c DT	381	le32_to_cpu(p->start_sect),
3fbf586c DT	382	le32_to_cpu(p->nr_sects));
1da177e4 LT	383	p++;
	384	}
	385	put_dev_sector(sect);
9c867fbe	386	strlcat(state->pp_buf, " >\n", PAGE_SIZE);
1da177e4 LT	387	#endif
	388	}
	389
	390	/*
	391	* Minix 2.0.0/2.0.2 subpartition support.
	392	* Anand Krishnamurthy <anandk@wiproge.med.ge.com>
	393	* Rajeev V. Pillai <rajeevvp@yahoo.com>
	394	*/
1493bf21 TH	395	static void parse_minix(struct parsed_partitions *state,
1493bf21 TH	396	sector_t offset, sector_t size, int origin)
1da177e4 LT	397	{
	398	#ifdef CONFIG_MINIX_SUBPARTITION
	399	Sector sect;
	400	unsigned char *data;
	401	struct partition *p;
	402	int i;
	403
1493bf21	404	data = read_part_sector(state, offset, &sect);
1da177e4 LT	405	if (!data)
	406	return;
	407
	408	p = (struct partition *)(data + 0x1be);
	409
	410	/* The first sector of a Minix partition can have either
	411	* a secondary MBR describing its subpartitions, or
	412	* the normal boot sector. */
dce14c23	413	if (msdos_magic_present(data + 510) &&
1da177e4	414	SYS_IND(p) == MINIX_PARTITION) { /* subpartition table present */
9c867fbe	415	char tmp[1 + BDEVNAME_SIZE + 10 + 9 + 1];
1da177e4	416
9c867fbe AD	417	snprintf(tmp, sizeof(tmp), " %s%d: <minix:", state->name, origin);
9c867fbe AD	418	strlcat(state->pp_buf, tmp, PAGE_SIZE);
1da177e4 LT	419	for (i = 0; i < MINIX_NR_SUBPARTITIONS; i++, p++) {
	420	if (state->next == state->limit)
	421	break;
	422	/* add each partition in use */
	423	if (SYS_IND(p) == MINIX_PARTITION)
	424	put_partition(state, state->next++,
3fbf586c	425	start_sect(p), nr_sects(p));
1da177e4	426	}
9c867fbe	427	strlcat(state->pp_buf, " >\n", PAGE_SIZE);
1da177e4 LT	428	}
	429	put_dev_sector(sect);
	430	#endif /* CONFIG_MINIX_SUBPARTITION */
	431	}
	432
	433	static struct {
	434	unsigned char id;
1493bf21	435	void (parse)(struct parsed_partitions , sector_t, sector_t, int);
1da177e4 LT	436	} subtypes[] = {
	437	{FREEBSD_PARTITION, parse_freebsd},
	438	{NETBSD_PARTITION, parse_netbsd},
	439	{OPENBSD_PARTITION, parse_openbsd},
	440	{MINIX_PARTITION, parse_minix},
	441	{UNIXWARE_PARTITION, parse_unixware},
	442	{SOLARIS_X86_PARTITION, parse_solaris_x86},
	443	{NEW_SOLARIS_X86_PARTITION, parse_solaris_x86},
	444	{0, NULL},
	445	};
1d04f3c6	446
1493bf21	447	int msdos_partition(struct parsed_partitions *state)
1da177e4	448	{
1493bf21	449	sector_t sector_size = bdev_logical_block_size(state->bdev) / 512;
1da177e4 LT	450	Sector sect;
	451	unsigned char *data;
	452	struct partition *p;
0607fd02	453	struct fat_boot_sector *fb;
1da177e4	454	int slot;
d33b98fc	455	u32 disksig;
1da177e4	456
1493bf21	457	data = read_part_sector(state, 0, &sect);
1da177e4 LT	458	if (!data)
1da177e4 LT	459	return -1;
86ee8ba6 PDM	460
	461	/*
	462	* Note order! (some AIX disks, e.g. unbootable kind,
	463	* have no MSDOS 55aa)
	464	*/
	465	if (aix_magic_present(state, data)) {
1da177e4	466	put_dev_sector(sect);
f8f06603 PDM	467	#ifdef CONFIG_AIX_PARTITION
	468	return aix_partition(state);
	469	#else
86ee8ba6	470	strlcat(state->pp_buf, " [AIX]", PAGE_SIZE);
1da177e4	471	return 0;
f8f06603	472	#endif
1da177e4 LT	473	}
1da177e4 LT	474
86ee8ba6	475	if (!msdos_magic_present(data + 510)) {
e1dfa92d	476	put_dev_sector(sect);
e1dfa92d OH	477	return 0;
	478	}
	479
1da177e4 LT	480	/*
	481	* Now that the 55aa signature is present, this is probably
	482	* either the boot sector of a FAT filesystem or a DOS-type
	483	* partition table. Reject this in case the boot indicator
	484	* is not 0 or 0x80.
	485	*/
	486	p = (struct partition *) (data + 0x1be);
	487	for (slot = 1; slot <= 4; slot++, p++) {
	488	if (p->boot_ind != 0 && p->boot_ind != 0x80) {
0607fd02 FS	489	/*
	490	* Even without a valid boot inidicator value
	491	* its still possible this is valid FAT filesystem
	492	* without a partition table.
	493	*/
	494	fb = (struct fat_boot_sector *) data;
	495	if (slot == 1 && fb->reserved && fb->fats
	496	&& fat_valid_media(fb->media)) {
9c867fbe	497	strlcat(state->pp_buf, "\n", PAGE_SIZE);
0607fd02 FS	498	put_dev_sector(sect);
	499	return 1;
	500	} else {
	501	put_dev_sector(sect);
	502	return 0;
	503	}
1da177e4 LT	504	}
	505	}
	506
	507	#ifdef CONFIG_EFI_PARTITION
	508	p = (struct partition *) (data + 0x1be);
	509	for (slot = 1 ; slot <= 4 ; slot++, p++) {
	510	/* If this is an EFI GPT disk, msdos should ignore it. */
	511	if (SYS_IND(p) == EFI_PMBR_OSTYPE_EFI_GPT) {
	512	put_dev_sector(sect);
	513	return 0;
	514	}
	515	}
	516	#endif
	517	p = (struct partition *) (data + 0x1be);
	518
d33b98fc SW	519	disksig = le32_to_cpup((__le32 *)(data + 0x1b8));
d33b98fc SW	520
1da177e4 LT	521	/*
	522	* Look for partitions in two passes:
	523	* First find the primary and DOS-type extended partitions.
	524	* On the second pass look inside *BSD, Unixware and Solaris partitions.
	525	*/
	526
	527	state->next = 5;
	528	for (slot = 1 ; slot <= 4 ; slot++, p++) {
3fbf586c DT	529	sector_t start = start_sect(p)*sector_size;
3fbf586c DT	530	sector_t size = nr_sects(p)*sector_size;
dce14c23	531
1da177e4 LT	532	if (!size)
	533	continue;
	534	if (is_extended_partition(p)) {
8e0cc811 OH	535	/*
	536	* prevent someone doing mkfs or mkswap on an
	537	* extended partition, but leave room for LILO
	538	* FIXME: this uses one logical sector for > 512b
	539	* sector, although it may not be enough/proper.
	540	*/
	541	sector_t n = 2;
dce14c23	542
8e0cc811 OH	543	n = min(size, max(sector_size, n));
	544	put_partition(state, slot, start, n);
	545
9c867fbe	546	strlcat(state->pp_buf, " <", PAGE_SIZE);
d33b98fc	547	parse_extended(state, start, size, disksig);
9c867fbe	548	strlcat(state->pp_buf, " >", PAGE_SIZE);
1da177e4 LT	549	continue;
	550	}
	551	put_partition(state, slot, start, size);
d33b98fc	552	set_info(state, slot, disksig);
1da177e4	553	if (SYS_IND(p) == LINUX_RAID_PARTITION)
cc910624	554	state->parts[slot].flags = ADDPART_FLAG_RAID;
1da177e4	555	if (SYS_IND(p) == DM6_PARTITION)
9c867fbe	556	strlcat(state->pp_buf, "[DM]", PAGE_SIZE);
1da177e4	557	if (SYS_IND(p) == EZD_PARTITION)
9c867fbe	558	strlcat(state->pp_buf, "[EZD]", PAGE_SIZE);
1da177e4 LT	559	}
1da177e4 LT	560
9c867fbe	561	strlcat(state->pp_buf, "\n", PAGE_SIZE);
1da177e4 LT	562
	563	/* second pass - output for each on a separate line */
	564	p = (struct partition *) (0x1be + data);
	565	for (slot = 1 ; slot <= 4 ; slot++, p++) {
	566	unsigned char id = SYS_IND(p);
	567	int n;
	568
3fbf586c	569	if (!nr_sects(p))
1da177e4 LT	570	continue;
	571
	572	for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++)
	573	;
	574
	575	if (!subtypes[n].parse)
	576	continue;
1493bf21 TH	577	subtypes[n].parse(state, start_sect(p) * sector_size,
1493bf21 TH	578	nr_sects(p) * sector_size, slot);
1da177e4 LT	579	}
	580	put_dev_sector(sect);
	581	return 1;
	582	}