/*
   *  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>
  ",
  			 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, " >
  ", 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
  ", 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, " >
  ", 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, " >
  ", 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, " >
  ", 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, "
  ", 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, "
  ", 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;
  }