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author | Al Viro <viro@zeniv.linux.org.uk> | 2011-09-16 04:25:05 (GMT) |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2012-01-04 03:54:06 (GMT) |
commit | 9be96f3fd10187f185d84cf878cf032465bcced3 (patch) | |
tree | 432a430ed9e0cbe0c18916cd3c3992f09b3feb37 /block/partitions/msdos.c | |
parent | 4752bc309b7604d507c973c7b7678ac2ce10a058 (diff) | |
download | linux-fsl-qoriq-9be96f3fd10187f185d84cf878cf032465bcced3.tar.xz |
move fs/partitions to block/
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'block/partitions/msdos.c')
-rw-r--r-- | block/partitions/msdos.c | 552 |
1 files changed, 552 insertions, 0 deletions
diff --git a/block/partitions/msdos.c b/block/partitions/msdos.c new file mode 100644 index 0000000..5f79a66 --- /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, §); + 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, §); + 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, §); + 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, §); + 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, §); + 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, §); + 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, §); + 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; +} |