msdos.rar_V2

/* * 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" #include "aix.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; } static void set_info(struct parsed_partitions *state, int slot, u32 disksig) { struct partition_meta_info *info = &state->parts[slot].info; snprintf(info->uuid, sizeof(info->uuid), "%08x-%02x", disksig, slot); info->volname[0] = 0; state->parts[slot].has_info = true; } /* * 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, u32 disksig) { 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); set_info(state, state->next, disksig); 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) ret