1 files changed, 552 insertions, 0 deletions

diff --git a/block/partitions/msdos.c b/block/partitions/msdos.c
new file mode 100644
index 000000000000..5f79a6677c69
--- /dev/null
+++ b/block/partitions/msdos.c
@@ -0,0 +1,552 @@
+/*
+ *  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>\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;
+
+        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, "\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);
+
+        /*
+         * 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, "\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;
+}