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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/partitions/msdos.c
downloadop-kernel-dev-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip
op-kernel-dev-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'fs/partitions/msdos.c')
-rw-r--r--fs/partitions/msdos.c479
1 files changed, 479 insertions, 0 deletions
diff --git a/fs/partitions/msdos.c b/fs/partitions/msdos.c
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+/*
+ * 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/config.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))
+#define NR_SECTS(p) ({ __typeof__(p->nr_sects) __a = \
+ get_unaligned(&p->nr_sects); \
+ le32_to_cpu(__a); \
+ })
+
+#define START_SECT(p) ({ __typeof__(p->start_sect) __a = \
+ get_unaligned(&p->start_sect); \
+ le32_to_cpu(__a); \
+ })
+
+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);
+}
+
+/*
+ * 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, struct block_device *bdev,
+ u32 first_sector, u32 first_size)
+{
+ struct partition *p;
+ Sector sect;
+ unsigned char *data;
+ u32 this_sector, this_size;
+ int sector_size = bdev_hardsect_size(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_dev_sector(bdev, 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++) {
+ u32 offs, size, next;
+
+ if (SYS_IND(p) == 0)
+ continue;
+ 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 = 1;
+ 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, struct block_device *bdev,
+ u32 offset, u32 size, int origin)
+{
+#ifdef CONFIG_SOLARIS_X86_PARTITION
+ Sector sect;
+ struct solaris_x86_vtoc *v;
+ int i;
+
+ v = (struct solaris_x86_vtoc *)read_dev_sector(bdev, offset+1, &sect);
+ if (!v)
+ return;
+ if (le32_to_cpu(v->v_sanity) != SOLARIS_X86_VTOC_SANE) {
+ put_dev_sector(sect);
+ return;
+ }
+ printk(" %s%d: <solaris:", state->name, origin);
+ if (le32_to_cpu(v->v_version) != 1) {
+ printk(" cannot handle version %d vtoc>\n",
+ le32_to_cpu(v->v_version));
+ put_dev_sector(sect);
+ return;
+ }
+ for (i=0; i<SOLARIS_X86_NUMSLICE && state->next<state->limit; i++) {
+ struct solaris_x86_slice *s = &v->v_slice[i];
+ if (s->s_size == 0)
+ continue;
+ printk(" [s%d]", i);
+ /* 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);
+ printk(" >\n");
+#endif
+}
+
+#if defined(CONFIG_BSD_DISKLABEL) || defined(CONFIG_NEC98_PARTITION)
+/*
+ * Create devices for BSD partitions listed in a disklabel, under a
+ * dos-like partition. See parse_extended() for more information.
+ */
+void
+parse_bsd(struct parsed_partitions *state, struct block_device *bdev,
+ u32 offset, u32 size, int origin, char *flavour,
+ int max_partitions)
+{
+ Sector sect;
+ struct bsd_disklabel *l;
+ struct bsd_partition *p;
+
+ l = (struct bsd_disklabel *)read_dev_sector(bdev, offset+1, &sect);
+ if (!l)
+ return;
+ if (le32_to_cpu(l->d_magic) != BSD_DISKMAGIC) {
+ put_dev_sector(sect);
+ return;
+ }
+ printk(" %s%d: <%s:", state->name, origin, flavour);
+
+ 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++) {
+ u32 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) {
+ printk("bad subpartition - ignored\n");
+ continue;
+ }
+ put_partition(state, state->next++, bsd_start, bsd_size);
+ }
+ put_dev_sector(sect);
+ if (le16_to_cpu(l->d_npartitions) > max_partitions)
+ printk(" (ignored %d more)",
+ le16_to_cpu(l->d_npartitions) - max_partitions);
+ printk(" >\n");
+}
+#endif
+
+static void
+parse_freebsd(struct parsed_partitions *state, struct block_device *bdev,
+ u32 offset, u32 size, int origin)
+{
+#ifdef CONFIG_BSD_DISKLABEL
+ parse_bsd(state, bdev, offset, size, origin,
+ "bsd", BSD_MAXPARTITIONS);
+#endif
+}
+
+static void
+parse_netbsd(struct parsed_partitions *state, struct block_device *bdev,
+ u32 offset, u32 size, int origin)
+{
+#ifdef CONFIG_BSD_DISKLABEL
+ parse_bsd(state, bdev, offset, size, origin,
+ "netbsd", BSD_MAXPARTITIONS);
+#endif
+}
+
+static void
+parse_openbsd(struct parsed_partitions *state, struct block_device *bdev,
+ u32 offset, u32 size, int origin)
+{
+#ifdef CONFIG_BSD_DISKLABEL
+ parse_bsd(state, bdev, 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, struct block_device *bdev,
+ u32 offset, u32 size, int origin)
+{
+#ifdef CONFIG_UNIXWARE_DISKLABEL
+ Sector sect;
+ struct unixware_disklabel *l;
+ struct unixware_slice *p;
+
+ l = (struct unixware_disklabel *)read_dev_sector(bdev, 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;
+ }
+ printk(" %s%d: <unixware:", state->name, origin);
+ 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++,
+ START_SECT(p), NR_SECTS(p));
+ p++;
+ }
+ put_dev_sector(sect);
+ printk(" >\n");
+#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, struct block_device *bdev,
+ u32 offset, u32 size, int origin)
+{
+#ifdef CONFIG_MINIX_SUBPARTITION
+ Sector sect;
+ unsigned char *data;
+ struct partition *p;
+ int i;
+
+ data = read_dev_sector(bdev, 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 */
+
+ printk(" %s%d: <minix:", state->name, origin);
+ 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));
+ }
+ printk(" >\n");
+ }
+ put_dev_sector(sect);
+#endif /* CONFIG_MINIX_SUBPARTITION */
+}
+
+static struct {
+ unsigned char id;
+ void (*parse)(struct parsed_partitions *, struct block_device *,
+ u32, u32, 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, struct block_device *bdev)
+{
+ int sector_size = bdev_hardsect_size(bdev) / 512;
+ Sector sect;
+ unsigned char *data;
+ struct partition *p;
+ int slot;
+
+ data = read_dev_sector(bdev, 0, &sect);
+ if (!data)
+ return -1;
+ 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) {
+ 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++) {
+ u32 start = START_SECT(p)*sector_size;
+ u32 size = NR_SECTS(p)*sector_size;
+ if (SYS_IND(p) == 0)
+ continue;
+ if (!size)
+ continue;
+ if (is_extended_partition(p)) {
+ /* prevent someone doing mkfs or mkswap on an
+ extended partition, but leave room for LILO */
+ put_partition(state, slot, start, size == 1 ? 1 : 2);
+ printk(" <");
+ parse_extended(state, bdev, start, size);
+ printk(" >");
+ continue;
+ }
+ put_partition(state, slot, start, size);
+ if (SYS_IND(p) == LINUX_RAID_PARTITION)
+ state->parts[slot].flags = 1;
+ if (SYS_IND(p) == DM6_PARTITION)
+ printk("[DM]");
+ if (SYS_IND(p) == EZD_PARTITION)
+ printk("[EZD]");
+ }
+
+ printk("\n");
+
+ /* 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, bdev, START_SECT(p)*sector_size,
+ NR_SECTS(p)*sector_size, slot);
+ }
+ put_dev_sector(sect);
+ return 1;
+}
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