1 files changed, 479 insertions, 0 deletions

diff --git a/fs/partitions/msdos.c b/fs/partitions/msdos.c
new file mode 100644
index 000000000000..17ee1b4ff087
--- /dev/null
+++ b/fs/partitions/msdos.c
@@ -0,0 +1,479 @@
+/*
+ *  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;
+}