cregit-Linux how code gets into the kernel

Release 4.11 block/partitions/msdos.c

Directory: block/partitions
/*
 *  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); }

Contributors

PersonTokensPropCommitsCommitProp
Daniel Taylor2187.50%150.00%
Linus Torvalds (pre-git)312.50%150.00%
Total24100.00%2100.00%


static inline sector_t start_sect(struct partition *p) { return (sector_t)get_unaligned_le32(&p->start_sect); }

Contributors

PersonTokensPropCommitsCommitProp
Daniel Taylor2187.50%150.00%
Linus Torvalds (pre-git)312.50%150.00%
Total24100.00%2100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)36100.00%1100.00%
Total36100.00%1100.00%

#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); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds29100.00%1100.00%
Total29100.00%1100.00%

/* 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; }

Contributors

PersonTokensPropCommitsCommitProp
Olaf Hering18996.43%375.00%
Tejun Heo73.57%125.00%
Total196100.00%4100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Stephen Warren72100.00%1100.00%
Total72100.00%1100.00%

/* * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)21857.82%323.08%
Linus Torvalds9424.93%323.08%
Al Viro338.75%17.69%
Stephen Warren143.71%17.69%
Daniel Taylor112.92%17.69%
Tejun Heo41.06%17.69%
Fabio Massimo Di Nitto10.27%17.69%
Philippe De Muyter10.27%17.69%
Martin K. Petersen10.27%17.69%
Total377100.00%13100.00%

/* 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 }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)11937.30%222.22%
Alexey Dobriyan9830.72%111.11%
Linus Torvalds4614.42%222.22%
Al Viro3210.03%111.11%
Mark Fortescue206.27%111.11%
Daniel Taylor20.63%111.11%
Tejun Heo20.63%111.11%
Total319100.00%9100.00%

#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); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)10232.38%218.18%
Alexey Dobriyan6019.05%19.09%
Al Viro5718.10%19.09%
Linus Torvalds3912.38%218.18%
Andries E. Brouwer278.57%19.09%
Roland McGrath247.62%19.09%
Daniel Taylor30.95%19.09%
Tejun Heo20.63%19.09%
Adrian Bunk10.32%19.09%
Total315100.00%11100.00%

#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 }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds1742.50%125.00%
Al Viro1332.50%125.00%
Linus Torvalds (pre-git)820.00%125.00%
Daniel Taylor25.00%125.00%
Total40100.00%4100.00%


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 }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds1845.00%125.00%
Al Viro1332.50%125.00%
Linus Torvalds (pre-git)717.50%125.00%
Daniel Taylor25.00%125.00%
Total40100.00%4100.00%


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 }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds2562.50%133.33%
Al Viro1332.50%133.33%
Daniel Taylor25.00%133.33%
Total40100.00%3100.00%

/* * 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 }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)9039.82%228.57%
Linus Torvalds6026.55%114.29%
Alexey Dobriyan4218.58%114.29%
Al Viro2410.62%114.29%
Daniel Taylor83.54%114.29%
Tejun Heo20.88%114.29%
Total226100.00%7100.00%

/* * 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 */ }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds14166.82%342.86%
Alexey Dobriyan4018.96%114.29%
Al Viro2411.37%114.29%
Daniel Taylor41.90%114.29%
Tejun Heo20.95%114.29%
Total211100.00%7100.00%

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; u32 disksig; data = read_part_sector(state, 0, &sect); if (!data) return -1; /* * Note order! (some AIX disks, e.g. unbootable kind, * have no MSDOS 55aa) */ if (aix_magic_present(state, data)) { put_dev_sector(sect); #ifdef CONFIG_AIX_PARTITION return aix_partition(state); #else strlcat(state->pp_buf, " [AIX]", PAGE_SIZE); return 0; #endif } 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) { /* * 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); disksig = le32_to_cpup((__le32 *)(data + 0x1b8)); /* * 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, disksig); strlcat(state->pp_buf, " >", PAGE_SIZE); continue; } put_partition(state, slot, start, size); set_info(state, slot, disksig); 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; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds11417.12%313.04%
Linus Torvalds (pre-git)11116.67%313.04%
Al Viro9313.96%14.35%
Andrew Morton588.71%14.35%
Frank Seidel537.96%14.35%
Dave Jones517.66%14.35%
Alexey Dobriyan426.31%14.35%
Philippe De Muyter324.80%28.70%
Andries E. Brouwer324.80%313.04%
Stephen Warren294.35%14.35%
Hirofumi Ogawa213.15%14.35%
Olaf Hering152.25%14.35%
Daniel Taylor81.20%14.35%
Tejun Heo50.75%14.35%
Martin K. Petersen10.15%14.35%
Cesar Eduardo Barros10.15%14.35%
Total666100.00%23100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)72626.32%513.16%
Linus Torvalds64523.39%410.53%
Al Viro31111.28%12.63%
Alexey Dobriyan28210.22%12.63%
Olaf Hering2218.01%37.89%
Stephen Warren1154.17%12.63%
Daniel Taylor873.15%12.63%
Andries E. Brouwer672.43%718.42%
Andrew Morton632.28%25.26%
Frank Seidel562.03%12.63%
Dave Jones541.96%12.63%
Philippe De Muyter371.34%37.89%
Tejun Heo240.87%12.63%
Roland McGrath240.87%12.63%
Hirofumi Ogawa210.76%12.63%
Mark Fortescue200.73%12.63%
Martin K. Petersen20.07%12.63%
Adrian Bunk10.04%12.63%
Cesar Eduardo Barros10.04%12.63%
Fabio Massimo Di Nitto10.04%12.63%
Total2758100.00%38100.00%
Directory: block/partitions
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.