/* * 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, §); 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 (!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, §); 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) /* * 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, 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, §); 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, §); 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, §); 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, §); 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 (!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; }