475 lines
13 KiB
C
475 lines
13 KiB
C
/*
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* fs/partitions/msdos.c
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*
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* Code extracted from drivers/block/genhd.c
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* Copyright (C) 1991-1998 Linus Torvalds
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*
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* Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug
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* in the early extended-partition checks and added DM partitions
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*
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* Support for DiskManager v6.0x added by Mark Lord,
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* with information provided by OnTrack. This now works for linux fdisk
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* and LILO, as well as loadlin and bootln. Note that disks other than
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* /dev/hda *must* have a "DOS" type 0x51 partition in the first slot (hda1).
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*
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* More flexible handling of extended partitions - aeb, 950831
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*
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* Check partition table on IDE disks for common CHS translations
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*
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* Re-organised Feb 1998 Russell King
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*/
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#include <linux/config.h>
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#include "check.h"
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#include "msdos.h"
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#include "efi.h"
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/*
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* Many architectures don't like unaligned accesses, while
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* the nr_sects and start_sect partition table entries are
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* at a 2 (mod 4) address.
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*/
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#include <asm/unaligned.h>
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#define SYS_IND(p) (get_unaligned(&p->sys_ind))
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#define NR_SECTS(p) ({ __typeof__(p->nr_sects) __a = \
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get_unaligned(&p->nr_sects); \
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le32_to_cpu(__a); \
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})
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#define START_SECT(p) ({ __typeof__(p->start_sect) __a = \
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get_unaligned(&p->start_sect); \
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le32_to_cpu(__a); \
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})
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static inline int is_extended_partition(struct partition *p)
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{
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return (SYS_IND(p) == DOS_EXTENDED_PARTITION ||
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SYS_IND(p) == WIN98_EXTENDED_PARTITION ||
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SYS_IND(p) == LINUX_EXTENDED_PARTITION);
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}
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#define MSDOS_LABEL_MAGIC1 0x55
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#define MSDOS_LABEL_MAGIC2 0xAA
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static inline int
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msdos_magic_present(unsigned char *p)
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{
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return (p[0] == MSDOS_LABEL_MAGIC1 && p[1] == MSDOS_LABEL_MAGIC2);
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}
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/*
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* Create devices for each logical partition in an extended partition.
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* The logical partitions form a linked list, with each entry being
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* a partition table with two entries. The first entry
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* is the real data partition (with a start relative to the partition
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* table start). The second is a pointer to the next logical partition
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* (with a start relative to the entire extended partition).
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* We do not create a Linux partition for the partition tables, but
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* only for the actual data partitions.
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*/
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static void
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parse_extended(struct parsed_partitions *state, struct block_device *bdev,
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u32 first_sector, u32 first_size)
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{
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struct partition *p;
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Sector sect;
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unsigned char *data;
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u32 this_sector, this_size;
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int sector_size = bdev_hardsect_size(bdev) / 512;
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int loopct = 0; /* number of links followed
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without finding a data partition */
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int i;
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this_sector = first_sector;
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this_size = first_size;
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while (1) {
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if (++loopct > 100)
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return;
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if (state->next == state->limit)
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return;
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data = read_dev_sector(bdev, this_sector, §);
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if (!data)
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return;
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if (!msdos_magic_present(data + 510))
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goto done;
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p = (struct partition *) (data + 0x1be);
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/*
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* Usually, the first entry is the real data partition,
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* the 2nd entry is the next extended partition, or empty,
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* and the 3rd and 4th entries are unused.
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* However, DRDOS sometimes has the extended partition as
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* the first entry (when the data partition is empty),
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* and OS/2 seems to use all four entries.
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*/
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/*
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* First process the data partition(s)
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*/
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for (i=0; i<4; i++, p++) {
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u32 offs, size, next;
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if (!NR_SECTS(p) || is_extended_partition(p))
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continue;
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/* Check the 3rd and 4th entries -
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these sometimes contain random garbage */
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offs = START_SECT(p)*sector_size;
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size = NR_SECTS(p)*sector_size;
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next = this_sector + offs;
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if (i >= 2) {
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if (offs + size > this_size)
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continue;
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if (next < first_sector)
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continue;
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if (next + size > first_sector + first_size)
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continue;
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}
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put_partition(state, state->next, next, size);
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if (SYS_IND(p) == LINUX_RAID_PARTITION)
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state->parts[state->next].flags = 1;
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loopct = 0;
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if (++state->next == state->limit)
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goto done;
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}
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/*
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* Next, process the (first) extended partition, if present.
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* (So far, there seems to be no reason to make
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* parse_extended() recursive and allow a tree
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* of extended partitions.)
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* It should be a link to the next logical partition.
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*/
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p -= 4;
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for (i=0; i<4; i++, p++)
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if (NR_SECTS(p) && is_extended_partition(p))
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break;
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if (i == 4)
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goto done; /* nothing left to do */
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this_sector = first_sector + START_SECT(p) * sector_size;
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this_size = NR_SECTS(p) * sector_size;
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put_dev_sector(sect);
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}
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done:
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put_dev_sector(sect);
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}
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/* james@bpgc.com: Solaris has a nasty indicator: 0x82 which also
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indicates linux swap. Be careful before believing this is Solaris. */
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static void
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parse_solaris_x86(struct parsed_partitions *state, struct block_device *bdev,
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u32 offset, u32 size, int origin)
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{
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#ifdef CONFIG_SOLARIS_X86_PARTITION
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Sector sect;
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struct solaris_x86_vtoc *v;
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int i;
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v = (struct solaris_x86_vtoc *)read_dev_sector(bdev, offset+1, §);
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if (!v)
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return;
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if (le32_to_cpu(v->v_sanity) != SOLARIS_X86_VTOC_SANE) {
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put_dev_sector(sect);
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return;
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}
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printk(" %s%d: <solaris:", state->name, origin);
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if (le32_to_cpu(v->v_version) != 1) {
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printk(" cannot handle version %d vtoc>\n",
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le32_to_cpu(v->v_version));
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put_dev_sector(sect);
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return;
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}
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for (i=0; i<SOLARIS_X86_NUMSLICE && state->next<state->limit; i++) {
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struct solaris_x86_slice *s = &v->v_slice[i];
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if (s->s_size == 0)
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continue;
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printk(" [s%d]", i);
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/* solaris partitions are relative to current MS-DOS
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* one; must add the offset of the current partition */
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put_partition(state, state->next++,
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le32_to_cpu(s->s_start)+offset,
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le32_to_cpu(s->s_size));
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}
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put_dev_sector(sect);
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printk(" >\n");
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#endif
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}
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#if defined(CONFIG_BSD_DISKLABEL)
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/*
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* Create devices for BSD partitions listed in a disklabel, under a
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* dos-like partition. See parse_extended() for more information.
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*/
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static void
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parse_bsd(struct parsed_partitions *state, struct block_device *bdev,
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u32 offset, u32 size, int origin, char *flavour,
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int max_partitions)
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{
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Sector sect;
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struct bsd_disklabel *l;
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struct bsd_partition *p;
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l = (struct bsd_disklabel *)read_dev_sector(bdev, offset+1, §);
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if (!l)
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return;
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if (le32_to_cpu(l->d_magic) != BSD_DISKMAGIC) {
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put_dev_sector(sect);
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return;
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}
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printk(" %s%d: <%s:", state->name, origin, flavour);
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if (le16_to_cpu(l->d_npartitions) < max_partitions)
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max_partitions = le16_to_cpu(l->d_npartitions);
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for (p = l->d_partitions; p - l->d_partitions < max_partitions; p++) {
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u32 bsd_start, bsd_size;
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if (state->next == state->limit)
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break;
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if (p->p_fstype == BSD_FS_UNUSED)
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continue;
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bsd_start = le32_to_cpu(p->p_offset);
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bsd_size = le32_to_cpu(p->p_size);
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if (offset == bsd_start && size == bsd_size)
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/* full parent partition, we have it already */
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continue;
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if (offset > bsd_start || offset+size < bsd_start+bsd_size) {
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printk("bad subpartition - ignored\n");
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continue;
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}
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put_partition(state, state->next++, bsd_start, bsd_size);
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}
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put_dev_sector(sect);
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if (le16_to_cpu(l->d_npartitions) > max_partitions)
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printk(" (ignored %d more)",
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le16_to_cpu(l->d_npartitions) - max_partitions);
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printk(" >\n");
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}
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#endif
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static void
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parse_freebsd(struct parsed_partitions *state, struct block_device *bdev,
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u32 offset, u32 size, int origin)
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{
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#ifdef CONFIG_BSD_DISKLABEL
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parse_bsd(state, bdev, offset, size, origin,
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"bsd", BSD_MAXPARTITIONS);
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#endif
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}
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static void
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parse_netbsd(struct parsed_partitions *state, struct block_device *bdev,
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u32 offset, u32 size, int origin)
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{
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#ifdef CONFIG_BSD_DISKLABEL
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parse_bsd(state, bdev, offset, size, origin,
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"netbsd", BSD_MAXPARTITIONS);
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#endif
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}
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static void
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parse_openbsd(struct parsed_partitions *state, struct block_device *bdev,
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u32 offset, u32 size, int origin)
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{
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#ifdef CONFIG_BSD_DISKLABEL
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parse_bsd(state, bdev, offset, size, origin,
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"openbsd", OPENBSD_MAXPARTITIONS);
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#endif
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}
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/*
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* Create devices for Unixware partitions listed in a disklabel, under a
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* dos-like partition. See parse_extended() for more information.
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*/
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static void
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parse_unixware(struct parsed_partitions *state, struct block_device *bdev,
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u32 offset, u32 size, int origin)
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{
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#ifdef CONFIG_UNIXWARE_DISKLABEL
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Sector sect;
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struct unixware_disklabel *l;
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struct unixware_slice *p;
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l = (struct unixware_disklabel *)read_dev_sector(bdev, offset+29, §);
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if (!l)
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return;
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if (le32_to_cpu(l->d_magic) != UNIXWARE_DISKMAGIC ||
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le32_to_cpu(l->vtoc.v_magic) != UNIXWARE_DISKMAGIC2) {
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put_dev_sector(sect);
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return;
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}
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printk(" %s%d: <unixware:", state->name, origin);
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p = &l->vtoc.v_slice[1];
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/* I omit the 0th slice as it is the same as whole disk. */
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while (p - &l->vtoc.v_slice[0] < UNIXWARE_NUMSLICE) {
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if (state->next == state->limit)
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break;
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if (p->s_label != UNIXWARE_FS_UNUSED)
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put_partition(state, state->next++,
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START_SECT(p), NR_SECTS(p));
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p++;
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}
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put_dev_sector(sect);
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printk(" >\n");
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#endif
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}
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/*
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* Minix 2.0.0/2.0.2 subpartition support.
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* Anand Krishnamurthy <anandk@wiproge.med.ge.com>
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* Rajeev V. Pillai <rajeevvp@yahoo.com>
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*/
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static void
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parse_minix(struct parsed_partitions *state, struct block_device *bdev,
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u32 offset, u32 size, int origin)
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{
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#ifdef CONFIG_MINIX_SUBPARTITION
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Sector sect;
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unsigned char *data;
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struct partition *p;
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int i;
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data = read_dev_sector(bdev, offset, §);
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if (!data)
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return;
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p = (struct partition *)(data + 0x1be);
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/* The first sector of a Minix partition can have either
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* a secondary MBR describing its subpartitions, or
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* the normal boot sector. */
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if (msdos_magic_present (data + 510) &&
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SYS_IND(p) == MINIX_PARTITION) { /* subpartition table present */
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printk(" %s%d: <minix:", state->name, origin);
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for (i = 0; i < MINIX_NR_SUBPARTITIONS; i++, p++) {
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if (state->next == state->limit)
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break;
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/* add each partition in use */
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if (SYS_IND(p) == MINIX_PARTITION)
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put_partition(state, state->next++,
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START_SECT(p), NR_SECTS(p));
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}
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printk(" >\n");
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}
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put_dev_sector(sect);
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#endif /* CONFIG_MINIX_SUBPARTITION */
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}
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static struct {
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unsigned char id;
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void (*parse)(struct parsed_partitions *, struct block_device *,
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u32, u32, int);
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} subtypes[] = {
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{FREEBSD_PARTITION, parse_freebsd},
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{NETBSD_PARTITION, parse_netbsd},
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{OPENBSD_PARTITION, parse_openbsd},
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{MINIX_PARTITION, parse_minix},
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{UNIXWARE_PARTITION, parse_unixware},
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{SOLARIS_X86_PARTITION, parse_solaris_x86},
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{NEW_SOLARIS_X86_PARTITION, parse_solaris_x86},
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{0, NULL},
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};
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int msdos_partition(struct parsed_partitions *state, struct block_device *bdev)
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{
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int sector_size = bdev_hardsect_size(bdev) / 512;
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Sector sect;
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unsigned char *data;
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struct partition *p;
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int slot;
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data = read_dev_sector(bdev, 0, §);
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if (!data)
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return -1;
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if (!msdos_magic_present(data + 510)) {
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put_dev_sector(sect);
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return 0;
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}
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/*
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* Now that the 55aa signature is present, this is probably
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* either the boot sector of a FAT filesystem or a DOS-type
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* partition table. Reject this in case the boot indicator
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* is not 0 or 0x80.
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*/
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p = (struct partition *) (data + 0x1be);
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for (slot = 1; slot <= 4; slot++, p++) {
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if (p->boot_ind != 0 && p->boot_ind != 0x80) {
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put_dev_sector(sect);
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return 0;
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}
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}
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#ifdef CONFIG_EFI_PARTITION
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p = (struct partition *) (data + 0x1be);
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for (slot = 1 ; slot <= 4 ; slot++, p++) {
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/* If this is an EFI GPT disk, msdos should ignore it. */
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if (SYS_IND(p) == EFI_PMBR_OSTYPE_EFI_GPT) {
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put_dev_sector(sect);
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return 0;
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}
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}
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#endif
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p = (struct partition *) (data + 0x1be);
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/*
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* Look for partitions in two passes:
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* First find the primary and DOS-type extended partitions.
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* On the second pass look inside *BSD, Unixware and Solaris partitions.
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*/
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state->next = 5;
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for (slot = 1 ; slot <= 4 ; slot++, p++) {
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u32 start = START_SECT(p)*sector_size;
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u32 size = NR_SECTS(p)*sector_size;
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if (!size)
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continue;
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if (is_extended_partition(p)) {
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/* prevent someone doing mkfs or mkswap on an
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extended partition, but leave room for LILO */
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put_partition(state, slot, start, size == 1 ? 1 : 2);
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printk(" <");
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parse_extended(state, bdev, start, size);
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printk(" >");
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continue;
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}
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put_partition(state, slot, start, size);
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if (SYS_IND(p) == LINUX_RAID_PARTITION)
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state->parts[slot].flags = 1;
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if (SYS_IND(p) == DM6_PARTITION)
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printk("[DM]");
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if (SYS_IND(p) == EZD_PARTITION)
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printk("[EZD]");
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}
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printk("\n");
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/* second pass - output for each on a separate line */
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p = (struct partition *) (0x1be + data);
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for (slot = 1 ; slot <= 4 ; slot++, p++) {
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unsigned char id = SYS_IND(p);
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int n;
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if (!NR_SECTS(p))
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continue;
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for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++)
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;
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if (!subtypes[n].parse)
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continue;
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subtypes[n].parse(state, bdev, START_SECT(p)*sector_size,
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NR_SECTS(p)*sector_size, slot);
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}
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put_dev_sector(sect);
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return 1;
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}
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