[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)
	161	*/
	162	for (i=0; i<4; i++, p++) {
3fbf586c DT	163	sector_t offs, size, next;
3fbf586c DT	164	if (!nr_sects(p) \|\| is_extended_partition(p))
1da177e4 LT	165	continue;
	166
	167	/* Check the 3rd and 4th entries -
	168	these sometimes contain random garbage */
3fbf586c DT	169	offs = start_sect(p)*sector_size;
3fbf586c DT	170	size = nr_sects(p)*sector_size;
1da177e4 LT	171	next = this_sector + offs;
	172	if (i >= 2) {
	173	if (offs + size > this_size)
	174	continue;
	175	if (next < first_sector)
	176	continue;
	177	if (next + size > first_sector + first_size)
	178	continue;
	179	}
	180
	181	put_partition(state, state->next, next, size);
d33b98fc	182	set_info(state, state->next, disksig);
1da177e4	183	if (SYS_IND(p) == LINUX_RAID_PARTITION)
d18d7682	184	state->parts[state->next].flags = ADDPART_FLAG_RAID;
1da177e4 LT	185	loopct = 0;
	186	if (++state->next == state->limit)
	187	goto done;
	188	}
	189	/*
	190	* Next, process the (first) extended partition, if present.
	191	* (So far, there seems to be no reason to make
	192	* parse_extended() recursive and allow a tree
	193	* of extended partitions.)
	194	* It should be a link to the next logical partition.
	195	*/
	196	p -= 4;
	197	for (i=0; i<4; i++, p++)
3fbf586c	198	if (nr_sects(p) && is_extended_partition(p))
1da177e4 LT	199	break;
	200	if (i == 4)
	201	goto done; /* nothing left to do */
	202
3fbf586c DT	203	this_sector = first_sector + start_sect(p) * sector_size;
3fbf586c DT	204	this_size = nr_sects(p) * sector_size;
1da177e4 LT	205	put_dev_sector(sect);
	206	}
	207	done:
	208	put_dev_sector(sect);
	209	}
	210
	211	/* james@bpgc.com: Solaris has a nasty indicator: 0x82 which also
	212	indicates linux swap. Be careful before believing this is Solaris. */
	213
1493bf21 TH	214	static void parse_solaris_x86(struct parsed_partitions *state,
1493bf21 TH	215	sector_t offset, sector_t size, int origin)
1da177e4 LT	216	{
	217	#ifdef CONFIG_SOLARIS_X86_PARTITION
	218	Sector sect;
	219	struct solaris_x86_vtoc *v;
	220	int i;
b84d8796	221	short max_nparts;
1da177e4	222
1493bf21	223	v = read_part_sector(state, offset + 1, &sect);
1da177e4 LT	224	if (!v)
	225	return;
	226	if (le32_to_cpu(v->v_sanity) != SOLARIS_X86_VTOC_SANE) {
	227	put_dev_sector(sect);
	228	return;
	229	}
9c867fbe AD	230	{
	231	char tmp[1 + BDEVNAME_SIZE + 10 + 11 + 1];
	232
	233	snprintf(tmp, sizeof(tmp), " %s%d: <solaris:", state->name, origin);
	234	strlcat(state->pp_buf, tmp, PAGE_SIZE);
	235	}
1da177e4	236	if (le32_to_cpu(v->v_version) != 1) {
9c867fbe AD	237	char tmp[64];
	238
	239	snprintf(tmp, sizeof(tmp), " cannot handle version %d vtoc>\n",
	240	le32_to_cpu(v->v_version));
	241	strlcat(state->pp_buf, tmp, PAGE_SIZE);
1da177e4 LT	242	put_dev_sector(sect);
	243	return;
	244	}
b84d8796 MF	245	/* Ensure we can handle previous case of VTOC with 8 entries gracefully */
	246	max_nparts = le16_to_cpu (v->v_nparts) > 8 ? SOLARIS_X86_NUMSLICE : 8;
	247	for (i=0; i<max_nparts && state->next<state->limit; i++) {
1da177e4	248	struct solaris_x86_slice *s = &v->v_slice[i];
9c867fbe AD	249	char tmp[3 + 10 + 1 + 1];
9c867fbe AD	250
1da177e4 LT	251	if (s->s_size == 0)
1da177e4 LT	252	continue;
9c867fbe AD	253	snprintf(tmp, sizeof(tmp), " [s%d]", i);
9c867fbe AD	254	strlcat(state->pp_buf, tmp, PAGE_SIZE);
1da177e4 LT	255	/* solaris partitions are relative to current MS-DOS
	256	* one; must add the offset of the current partition */
	257	put_partition(state, state->next++,
	258	le32_to_cpu(s->s_start)+offset,
	259	le32_to_cpu(s->s_size));
	260	}
	261	put_dev_sector(sect);
9c867fbe	262	strlcat(state->pp_buf, " >\n", PAGE_SIZE);
1da177e4 LT	263	#endif
	264	}
	265
486fd404	266	#if defined(CONFIG_BSD_DISKLABEL)
1d04f3c6	267	/*
1da177e4 LT	268	* Create devices for BSD partitions listed in a disklabel, under a
	269	* dos-like partition. See parse_extended() for more information.
	270	*/
1493bf21 TH	271	static void parse_bsd(struct parsed_partitions *state,
	272	sector_t offset, sector_t size, int origin, char *flavour,
	273	int max_partitions)
1da177e4 LT	274	{
	275	Sector sect;
	276	struct bsd_disklabel *l;
	277	struct bsd_partition *p;
9c867fbe	278	char tmp[64];
1da177e4	279
1493bf21	280	l = read_part_sector(state, offset + 1, &sect);
1da177e4 LT	281	if (!l)
	282	return;
	283	if (le32_to_cpu(l->d_magic) != BSD_DISKMAGIC) {
	284	put_dev_sector(sect);
	285	return;
	286	}
9c867fbe AD	287
	288	snprintf(tmp, sizeof(tmp), " %s%d: <%s:", state->name, origin, flavour);
	289	strlcat(state->pp_buf, tmp, PAGE_SIZE);
1da177e4 LT	290
	291	if (le16_to_cpu(l->d_npartitions) < max_partitions)
	292	max_partitions = le16_to_cpu(l->d_npartitions);
	293	for (p = l->d_partitions; p - l->d_partitions < max_partitions; p++) {
3fbf586c	294	sector_t bsd_start, bsd_size;
1da177e4 LT	295
	296	if (state->next == state->limit)
	297	break;
1d04f3c6	298	if (p->p_fstype == BSD_FS_UNUSED)
1da177e4 LT	299	continue;
	300	bsd_start = le32_to_cpu(p->p_offset);
	301	bsd_size = le32_to_cpu(p->p_size);
	302	if (offset == bsd_start && size == bsd_size)
	303	/* full parent partition, we have it already */
	304	continue;
	305	if (offset > bsd_start \|\| offset+size < bsd_start+bsd_size) {
9c867fbe	306	strlcat(state->pp_buf, "bad subpartition - ignored\n", PAGE_SIZE);
1da177e4 LT	307	continue;
	308	}
	309	put_partition(state, state->next++, bsd_start, bsd_size);
	310	}
	311	put_dev_sector(sect);
9c867fbe AD	312	if (le16_to_cpu(l->d_npartitions) > max_partitions) {
	313	snprintf(tmp, sizeof(tmp), " (ignored %d more)",
	314	le16_to_cpu(l->d_npartitions) - max_partitions);
	315	strlcat(state->pp_buf, tmp, PAGE_SIZE);
	316	}
	317	strlcat(state->pp_buf, " >\n", PAGE_SIZE);
1da177e4 LT	318	}
	319	#endif
	320
1493bf21 TH	321	static void parse_freebsd(struct parsed_partitions *state,
1493bf21 TH	322	sector_t offset, sector_t size, int origin)
1da177e4 LT	323	{
1da177e4 LT	324	#ifdef CONFIG_BSD_DISKLABEL
1493bf21	325	parse_bsd(state, offset, size, origin, "bsd", BSD_MAXPARTITIONS);
1da177e4 LT	326	#endif
	327	}
	328
1493bf21 TH	329	static void parse_netbsd(struct parsed_partitions *state,
1493bf21 TH	330	sector_t offset, sector_t size, int origin)
1da177e4 LT	331	{
1da177e4 LT	332	#ifdef CONFIG_BSD_DISKLABEL
1493bf21	333	parse_bsd(state, offset, size, origin, "netbsd", BSD_MAXPARTITIONS);
1da177e4 LT	334	#endif
	335	}
	336
1493bf21 TH	337	static void parse_openbsd(struct parsed_partitions *state,
1493bf21 TH	338	sector_t offset, sector_t size, int origin)
1da177e4 LT	339	{
1da177e4 LT	340	#ifdef CONFIG_BSD_DISKLABEL
1493bf21 TH	341	parse_bsd(state, offset, size, origin, "openbsd",
1493bf21 TH	342	OPENBSD_MAXPARTITIONS);
1da177e4 LT	343	#endif
	344	}
	345
	346	/*
	347	* Create devices for Unixware partitions listed in a disklabel, under a
	348	* dos-like partition. See parse_extended() for more information.
	349	*/
1493bf21 TH	350	static void parse_unixware(struct parsed_partitions *state,
1493bf21 TH	351	sector_t offset, sector_t size, int origin)
1da177e4 LT	352	{
	353	#ifdef CONFIG_UNIXWARE_DISKLABEL
	354	Sector sect;
	355	struct unixware_disklabel *l;
	356	struct unixware_slice *p;
	357
1493bf21	358	l = read_part_sector(state, offset + 29, &sect);
1da177e4 LT	359	if (!l)
	360	return;
	361	if (le32_to_cpu(l->d_magic) != UNIXWARE_DISKMAGIC \|\|
	362	le32_to_cpu(l->vtoc.v_magic) != UNIXWARE_DISKMAGIC2) {
	363	put_dev_sector(sect);
	364	return;
	365	}
9c867fbe AD	366	{
	367	char tmp[1 + BDEVNAME_SIZE + 10 + 12 + 1];
	368
	369	snprintf(tmp, sizeof(tmp), " %s%d: <unixware:", state->name, origin);
	370	strlcat(state->pp_buf, tmp, PAGE_SIZE);
	371	}
1da177e4 LT	372	p = &l->vtoc.v_slice[1];
	373	/* I omit the 0th slice as it is the same as whole disk. */
	374	while (p - &l->vtoc.v_slice[0] < UNIXWARE_NUMSLICE) {
	375	if (state->next == state->limit)
	376	break;
	377
	378	if (p->s_label != UNIXWARE_FS_UNUSED)
	379	put_partition(state, state->next++,
3fbf586c DT	380	le32_to_cpu(p->start_sect),
3fbf586c DT	381	le32_to_cpu(p->nr_sects));
1da177e4 LT	382	p++;
	383	}
	384	put_dev_sector(sect);
9c867fbe	385	strlcat(state->pp_buf, " >\n", PAGE_SIZE);
1da177e4 LT	386	#endif
	387	}
	388
	389	/*
	390	* Minix 2.0.0/2.0.2 subpartition support.
	391	* Anand Krishnamurthy <anandk@wiproge.med.ge.com>
	392	* Rajeev V. Pillai <rajeevvp@yahoo.com>
	393	*/
1493bf21 TH	394	static void parse_minix(struct parsed_partitions *state,
1493bf21 TH	395	sector_t offset, sector_t size, int origin)
1da177e4 LT	396	{
	397	#ifdef CONFIG_MINIX_SUBPARTITION
	398	Sector sect;
	399	unsigned char *data;
	400	struct partition *p;
	401	int i;
	402
1493bf21	403	data = read_part_sector(state, offset, &sect);
1da177e4 LT	404	if (!data)
	405	return;
	406
	407	p = (struct partition *)(data + 0x1be);
	408
	409	/* The first sector of a Minix partition can have either
	410	* a secondary MBR describing its subpartitions, or
	411	* the normal boot sector. */
	412	if (msdos_magic_present (data + 510) &&
	413	SYS_IND(p) == MINIX_PARTITION) { /* subpartition table present */
9c867fbe	414	char tmp[1 + BDEVNAME_SIZE + 10 + 9 + 1];
1da177e4	415
9c867fbe AD	416	snprintf(tmp, sizeof(tmp), " %s%d: <minix:", state->name, origin);
9c867fbe AD	417	strlcat(state->pp_buf, tmp, PAGE_SIZE);
1da177e4 LT	418	for (i = 0; i < MINIX_NR_SUBPARTITIONS; i++, p++) {
	419	if (state->next == state->limit)
	420	break;
	421	/* add each partition in use */
	422	if (SYS_IND(p) == MINIX_PARTITION)
	423	put_partition(state, state->next++,
3fbf586c	424	start_sect(p), nr_sects(p));
1da177e4	425	}
9c867fbe	426	strlcat(state->pp_buf, " >\n", PAGE_SIZE);
1da177e4 LT	427	}
	428	put_dev_sector(sect);
	429	#endif /* CONFIG_MINIX_SUBPARTITION */
	430	}
	431
	432	static struct {
	433	unsigned char id;
1493bf21	434	void (parse)(struct parsed_partitions , sector_t, sector_t, int);
1da177e4 LT	435	} subtypes[] = {
	436	{FREEBSD_PARTITION, parse_freebsd},
	437	{NETBSD_PARTITION, parse_netbsd},
	438	{OPENBSD_PARTITION, parse_openbsd},
	439	{MINIX_PARTITION, parse_minix},
	440	{UNIXWARE_PARTITION, parse_unixware},
	441	{SOLARIS_X86_PARTITION, parse_solaris_x86},
	442	{NEW_SOLARIS_X86_PARTITION, parse_solaris_x86},
	443	{0, NULL},
	444	};
1d04f3c6	445
1493bf21	446	int msdos_partition(struct parsed_partitions *state)
1da177e4	447	{
1493bf21	448	sector_t sector_size = bdev_logical_block_size(state->bdev) / 512;
1da177e4 LT	449	Sector sect;
	450	unsigned char *data;
	451	struct partition *p;
0607fd02	452	struct fat_boot_sector *fb;
1da177e4	453	int slot;
d33b98fc	454	u32 disksig;
1da177e4	455
1493bf21	456	data = read_part_sector(state, 0, &sect);
1da177e4 LT	457	if (!data)
1da177e4 LT	458	return -1;
86ee8ba6 PDM	459
	460	/*
	461	* Note order! (some AIX disks, e.g. unbootable kind,
	462	* have no MSDOS 55aa)
	463	*/
	464	if (aix_magic_present(state, data)) {
1da177e4	465	put_dev_sector(sect);
f8f06603 PDM	466	#ifdef CONFIG_AIX_PARTITION
	467	return aix_partition(state);
	468	#else
86ee8ba6	469	strlcat(state->pp_buf, " [AIX]", PAGE_SIZE);
1da177e4	470	return 0;
f8f06603	471	#endif
1da177e4 LT	472	}
1da177e4 LT	473
86ee8ba6	474	if (!msdos_magic_present(data + 510)) {
e1dfa92d	475	put_dev_sector(sect);
e1dfa92d OH	476	return 0;
	477	}
	478
1da177e4 LT	479	/*
	480	* Now that the 55aa signature is present, this is probably
	481	* either the boot sector of a FAT filesystem or a DOS-type
	482	* partition table. Reject this in case the boot indicator
	483	* is not 0 or 0x80.
	484	*/
	485	p = (struct partition *) (data + 0x1be);
	486	for (slot = 1; slot <= 4; slot++, p++) {
	487	if (p->boot_ind != 0 && p->boot_ind != 0x80) {
0607fd02 FS	488	/*
	489	* Even without a valid boot inidicator value
	490	* its still possible this is valid FAT filesystem
	491	* without a partition table.
	492	*/
	493	fb = (struct fat_boot_sector *) data;
	494	if (slot == 1 && fb->reserved && fb->fats
	495	&& fat_valid_media(fb->media)) {
9c867fbe	496	strlcat(state->pp_buf, "\n", PAGE_SIZE);
0607fd02 FS	497	put_dev_sector(sect);
	498	return 1;
	499	} else {
	500	put_dev_sector(sect);
	501	return 0;
	502	}
1da177e4 LT	503	}
	504	}
	505
	506	#ifdef CONFIG_EFI_PARTITION
	507	p = (struct partition *) (data + 0x1be);
	508	for (slot = 1 ; slot <= 4 ; slot++, p++) {
	509	/* If this is an EFI GPT disk, msdos should ignore it. */
	510	if (SYS_IND(p) == EFI_PMBR_OSTYPE_EFI_GPT) {
	511	put_dev_sector(sect);
	512	return 0;
	513	}
	514	}
	515	#endif
	516	p = (struct partition *) (data + 0x1be);
	517
d33b98fc SW	518	disksig = le32_to_cpup((__le32 *)(data + 0x1b8));
d33b98fc SW	519
1da177e4 LT	520	/*
	521	* Look for partitions in two passes:
	522	* First find the primary and DOS-type extended partitions.
	523	* On the second pass look inside *BSD, Unixware and Solaris partitions.
	524	*/
	525
	526	state->next = 5;
	527	for (slot = 1 ; slot <= 4 ; slot++, p++) {
3fbf586c DT	528	sector_t start = start_sect(p)*sector_size;
3fbf586c DT	529	sector_t size = nr_sects(p)*sector_size;
1da177e4 LT	530	if (!size)
	531	continue;
	532	if (is_extended_partition(p)) {
8e0cc811 OH	533	/*
	534	* prevent someone doing mkfs or mkswap on an
	535	* extended partition, but leave room for LILO
	536	* FIXME: this uses one logical sector for > 512b
	537	* sector, although it may not be enough/proper.
	538	*/
	539	sector_t n = 2;
	540	n = min(size, max(sector_size, n));
	541	put_partition(state, slot, start, n);
	542
9c867fbe	543	strlcat(state->pp_buf, " <", PAGE_SIZE);
d33b98fc	544	parse_extended(state, start, size, disksig);
9c867fbe	545	strlcat(state->pp_buf, " >", PAGE_SIZE);
1da177e4 LT	546	continue;
	547	}
	548	put_partition(state, slot, start, size);
d33b98fc	549	set_info(state, slot, disksig);
1da177e4	550	if (SYS_IND(p) == LINUX_RAID_PARTITION)
cc910624	551	state->parts[slot].flags = ADDPART_FLAG_RAID;
1da177e4	552	if (SYS_IND(p) == DM6_PARTITION)
9c867fbe	553	strlcat(state->pp_buf, "[DM]", PAGE_SIZE);
1da177e4	554	if (SYS_IND(p) == EZD_PARTITION)
9c867fbe	555	strlcat(state->pp_buf, "[EZD]", PAGE_SIZE);
1da177e4 LT	556	}
1da177e4 LT	557
9c867fbe	558	strlcat(state->pp_buf, "\n", PAGE_SIZE);
1da177e4 LT	559
	560	/* second pass - output for each on a separate line */
	561	p = (struct partition *) (0x1be + data);
	562	for (slot = 1 ; slot <= 4 ; slot++, p++) {
	563	unsigned char id = SYS_IND(p);
	564	int n;
	565
3fbf586c	566	if (!nr_sects(p))
1da177e4 LT	567	continue;
	568
	569	for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++)
	570	;
	571
	572	if (!subtypes[n].parse)
	573	continue;
1493bf21 TH	574	subtypes[n].parse(state, start_sect(p) * sector_size,
1493bf21 TH	575	nr_sects(p) * sector_size, slot);
1da177e4 LT	576	}
	577	put_dev_sector(sect);
	578	return 1;
	579	}