+++ /dev/null
-#ifndef _BLKID_FAT_H
-#define _BLKID_FAT_H
-
-/* This FAT superblock is required for:
- *
- * superblocks/vfat.c
- * partitions/dos.c
- */
-
-/* Yucky misaligned values */
-struct vfat_super_block {
-/* 00*/ unsigned char vs_ignored[3];
-/* 03*/ unsigned char vs_sysid[8];
-/* 0b*/ unsigned char vs_sector_size[2];
-/* 0d*/ uint8_t vs_cluster_size;
-/* 0e*/ uint16_t vs_reserved;
-/* 10*/ uint8_t vs_fats;
-/* 11*/ unsigned char vs_dir_entries[2];
-/* 13*/ unsigned char vs_sectors[2];
-/* 15*/ unsigned char vs_media;
-/* 16*/ uint16_t vs_fat_length;
-/* 18*/ uint16_t vs_secs_track;
-/* 1a*/ uint16_t vs_heads;
-/* 1c*/ uint32_t vs_hidden;
-/* 20*/ uint32_t vs_total_sect;
-/* 24*/ uint32_t vs_fat32_length;
-/* 28*/ uint16_t vs_flags;
-/* 2a*/ uint8_t vs_version[2];
-/* 2c*/ uint32_t vs_root_cluster;
-/* 30*/ uint16_t vs_fsinfo_sector;
-/* 32*/ uint16_t vs_backup_boot;
-/* 34*/ uint16_t vs_reserved2[6];
-/* 40*/ unsigned char vs_unknown[3];
-/* 43*/ unsigned char vs_serno[4];
-/* 47*/ unsigned char vs_label[11];
-/* 52*/ unsigned char vs_magic[8];
-/* 5a*/ unsigned char vs_dummy2[0x1fe - 0x5a];
-/*1fe*/ unsigned char vs_pmagic[2];
-} __attribute__((packed));
-
-/* Yucky misaligned values */
-struct msdos_super_block {
-/* 00*/ unsigned char ms_ignored[3];
-/* 03*/ unsigned char ms_sysid[8];
-/* 0b*/ unsigned char ms_sector_size[2];
-/* 0d*/ uint8_t ms_cluster_size;
-/* 0e*/ uint16_t ms_reserved;
-/* 10*/ uint8_t ms_fats;
-/* 11*/ unsigned char ms_dir_entries[2];
-/* 13*/ unsigned char ms_sectors[2]; /* =0 iff V3 or later */
-/* 15*/ unsigned char ms_media;
-/* 16*/ uint16_t ms_fat_length; /* Sectors per FAT */
-/* 18*/ uint16_t ms_secs_track;
-/* 1a*/ uint16_t ms_heads;
-/* 1c*/ uint32_t ms_hidden;
-/* V3 BPB */
-/* 20*/ uint32_t ms_total_sect; /* iff ms_sectors == 0 */
-/* V4 BPB */
-/* 24*/ unsigned char ms_unknown[3]; /* Phys drive no., resvd, V4 sig (0x29) */
-/* 27*/ unsigned char ms_serno[4];
-/* 2b*/ unsigned char ms_label[11];
-/* 36*/ unsigned char ms_magic[8];
-/* 3e*/ unsigned char ms_dummy2[0x1fe - 0x3e];
-/*1fe*/ unsigned char ms_pmagic[2];
-} __attribute__((packed));
-
-
-static inline int blkid_fat_valid_media(struct msdos_super_block *ms)
-{
- return 0xf8 <= ms->ms_media || ms->ms_media == 0xf0;
-}
-
-static inline int blkid_fat_valid_sectorsize(
- struct msdos_super_block *ms,
- uint16_t *sector_size)
-{
- unsigned char *tmp = (unsigned char *) &ms->ms_sector_size;
- uint16_t ssz;
-
- ssz = tmp[0] + (tmp[1] << 8);
-
- if (ssz != 0x200 && ssz != 0x400 && ssz != 0x800 && ssz != 0x1000)
- return 0;
- if (sector_size)
- *sector_size = ssz;
- return 1;
-}
-
-
-#endif /* _BLKID_FAT_H */
#include "superblocks.h"
-/* {msdos,vfat}_super_block is defined in ../fat.h */
-#include "fat.h"
+/* Yucky misaligned values */
+struct vfat_super_block {
+/* 00*/ unsigned char vs_ignored[3];
+/* 03*/ unsigned char vs_sysid[8];
+/* 0b*/ unsigned char vs_sector_size[2];
+/* 0d*/ uint8_t vs_cluster_size;
+/* 0e*/ uint16_t vs_reserved;
+/* 10*/ uint8_t vs_fats;
+/* 11*/ unsigned char vs_dir_entries[2];
+/* 13*/ unsigned char vs_sectors[2];
+/* 15*/ unsigned char vs_media;
+/* 16*/ uint16_t vs_fat_length;
+/* 18*/ uint16_t vs_secs_track;
+/* 1a*/ uint16_t vs_heads;
+/* 1c*/ uint32_t vs_hidden;
+/* 20*/ uint32_t vs_total_sect;
+/* 24*/ uint32_t vs_fat32_length;
+/* 28*/ uint16_t vs_flags;
+/* 2a*/ uint8_t vs_version[2];
+/* 2c*/ uint32_t vs_root_cluster;
+/* 30*/ uint16_t vs_fsinfo_sector;
+/* 32*/ uint16_t vs_backup_boot;
+/* 34*/ uint16_t vs_reserved2[6];
+/* 40*/ unsigned char vs_unknown[3];
+/* 43*/ unsigned char vs_serno[4];
+/* 47*/ unsigned char vs_label[11];
+/* 52*/ unsigned char vs_magic[8];
+/* 5a*/ unsigned char vs_dummy2[0x1fe - 0x5a];
+/*1fe*/ unsigned char vs_pmagic[2];
+} __attribute__((packed));
+
+/* Yucky misaligned values */
+struct msdos_super_block {
+/* 00*/ unsigned char ms_ignored[3];
+/* 03*/ unsigned char ms_sysid[8];
+/* 0b*/ unsigned char ms_sector_size[2];
+/* 0d*/ uint8_t ms_cluster_size;
+/* 0e*/ uint16_t ms_reserved;
+/* 10*/ uint8_t ms_fats;
+/* 11*/ unsigned char ms_dir_entries[2];
+/* 13*/ unsigned char ms_sectors[2]; /* =0 iff V3 or later */
+/* 15*/ unsigned char ms_media;
+/* 16*/ uint16_t ms_fat_length; /* Sectors per FAT */
+/* 18*/ uint16_t ms_secs_track;
+/* 1a*/ uint16_t ms_heads;
+/* 1c*/ uint32_t ms_hidden;
+/* V3 BPB */
+/* 20*/ uint32_t ms_total_sect; /* iff ms_sectors == 0 */
+/* V4 BPB */
+/* 24*/ unsigned char ms_unknown[3]; /* Phys drive no., resvd, V4 sig (0x29) */
+/* 27*/ unsigned char ms_serno[4];
+/* 2b*/ unsigned char ms_label[11];
+/* 36*/ unsigned char ms_magic[8];
+/* 3e*/ unsigned char ms_dummy2[0x1fe - 0x3e];
+/*1fe*/ unsigned char ms_pmagic[2];
+} __attribute__((packed));
struct vfat_dir_entry {
uint8_t name[11];
static const char *no_name = "NO NAME ";
+#define unaligned_le16(x) \
+ (((unsigned char *) x)[0] + (((unsigned char *) x)[1] << 8))
+
/*
* Look for LABEL (name) in the FAT root directory.
*/
return NULL;
}
-/*
- * The FAT filesystem could be without a magic string in superblock
- * (e.g. old floppies). This heuristic for FAT detection is inspired
- * by libvolume_id and the Linux kernel.
- */
-static int probe_fat_nomagic(blkid_probe pr, const struct blkid_idmag *mag)
+static int fat_valid_superblock(const struct blkid_idmag *mag,
+ struct msdos_super_block *ms,
+ struct vfat_super_block *vs,
+ uint32_t *cluster_count, uint32_t *fat_size)
{
- struct msdos_super_block *ms;
+ uint16_t sector_size, dir_entries, reserved;
+ uint32_t sect_count, __fat_size, dir_size, __cluster_count, fat_length;
+ uint32_t max_count;
- ms = blkid_probe_get_sb(pr, mag, struct msdos_super_block);
- if (!ms)
- return -1;
+ /* extra check for FATs without magic strings */
+ if (mag->len <= 2) {
+ /* Old floppies have a valid MBR signature */
+ if (ms->ms_pmagic[0] != 0x55 || ms->ms_pmagic[1] != 0xAA)
+ return 0;
- /* Old floppies have a valid MBR signature */
- if (ms->ms_pmagic[0] != 0x55 || ms->ms_pmagic[1] != 0xAA)
- return 1;
+ if (ms->ms_heads == 0)
+ return 0;
+ /*
+ * OS/2 and apparently DFSee will place a FAT12/16-like
+ * pseudo-superblock in the first 512 bytes of non-FAT
+ * filesystems --- at least JFS and HPFS, and possibly others.
+ * So we explicitly check for those filesystems at the
+ * FAT12/16 filesystem magic field identifier, and if they are
+ * present, we rule this out as a FAT filesystem, despite the
+ * FAT-like pseudo-header.
+ */
+ if ((memcmp(ms->ms_magic, "JFS ", 8) == 0) ||
+ (memcmp(ms->ms_magic, "HPFS ", 8) == 0))
+ return 0;
+ }
- /* heads check */
- if (ms->ms_heads == 0)
- return 1;
+ /* fat counts(Linux kernel expects at least 1 FAT table) */
+ if (!ms->ms_fats)
+ return 0;
+ if (!ms->ms_reserved)
+ return 0;
+ if (!(0xf8 <= ms->ms_media || ms->ms_media == 0xf0))
+ return 0;
+ if (!is_power_of_2(ms->ms_cluster_size))
+ return 0;
+
+ sector_size = unaligned_le16(&ms->ms_sector_size);
+ if (!is_power_of_2(sector_size) ||
+ sector_size < 512 || sector_size > 4096)
+ return 0;
+
+ dir_entries = unaligned_le16(&ms->ms_dir_entries);
+ reserved = le16_to_cpu(ms->ms_reserved);
+ sect_count = unaligned_le16(&ms->ms_sectors);
- /* cluster size check*/
- if (ms->ms_cluster_size == 0 ||
- (ms->ms_cluster_size & (ms->ms_cluster_size-1)))
- return 1;
+ if (sect_count == 0)
+ sect_count = le32_to_cpu(ms->ms_total_sect);
- /* media check */
- if (!blkid_fat_valid_media(ms))
- return 1;
+ fat_length = le16_to_cpu(ms->ms_fat_length);
+ if (fat_length == 0)
+ fat_length = le32_to_cpu(vs->vs_fat32_length);
- /* fat counts(Linux kernel expects at least 1 FAT table) */
- if (!ms->ms_fats)
- return 1;
+ __fat_size = fat_length * ms->ms_fats;
+ dir_size = ((dir_entries * sizeof(struct vfat_dir_entry)) +
+ (sector_size-1)) / sector_size;
- /*
- * OS/2 and apparently DFSee will place a FAT12/16-like
- * pseudo-superblock in the first 512 bytes of non-FAT
- * filesystems --- at least JFS and HPFS, and possibly others.
- * So we explicitly check for those filesystems at the
- * FAT12/16 filesystem magic field identifier, and if they are
- * present, we rule this out as a FAT filesystem, despite the
- * FAT-like pseudo-header.
- */
- if ((memcmp(ms->ms_magic, "JFS ", 8) == 0) ||
- (memcmp(ms->ms_magic, "HPFS ", 8) == 0))
- return 1;
+ __cluster_count = (sect_count - (reserved + __fat_size + dir_size)) /
+ ms->ms_cluster_size;
+ if (!ms->ms_fat_length && vs->vs_fat32_length)
+ max_count = FAT32_MAX;
+ else
+ max_count = __cluster_count > FAT12_MAX ? FAT16_MAX : FAT12_MAX;
- return 0;
+ if (__cluster_count > max_count)
+ return 0;
+
+ if (fat_size)
+ *fat_size = __fat_size;
+ if (cluster_count)
+ *cluster_count = __cluster_count;
+
+ return 1; /* valid */
}
-/* FAT label extraction from the root directory taken from Kay
- * Sievers's volume_id library */
-static int probe_vfat(blkid_probe pr, const struct blkid_idmag *mag)
+/*
+ * This function is used by MBR partition table parser to avoid
+ * misinterpretation of FAT filesystem.
+ */
+int blkid_probe_is_vfat(blkid_probe pr)
{
struct vfat_super_block *vs;
struct msdos_super_block *ms;
- const unsigned char *vol_label = 0, *tmp;
- unsigned char *vol_serno, vol_label_buf[11];
- int maxloop = 100;
- uint16_t sector_size, dir_entries, reserved;
- uint32_t sect_count, fat_size, dir_size, cluster_count, fat_length;
- uint32_t buf_size, start_data_sect, next, root_start, root_dir_entries;
- const char *version = NULL;
+ const struct blkid_idmag *mag = NULL;
- /* non-standard magic strings */
- if (mag->len <= 2 && probe_fat_nomagic(pr, mag) != 0)
- return 1;
+ if (blkid_probe_get_idmag(pr, &vfat_idinfo, NULL, &mag) || !mag)
+ return 0;
+ ms = blkid_probe_get_sb(pr, mag, struct msdos_super_block);
+ if (!ms)
+ return 0;
vs = blkid_probe_get_sb(pr, mag, struct vfat_super_block);
if (!vs)
- return -1;
+ return 0;
+
+ return fat_valid_superblock(mag, ms, vs, NULL, NULL);
+}
+
+/* FAT label extraction from the root directory taken from Kay
+ * Sievers's volume_id library */
+static int probe_vfat(blkid_probe pr, const struct blkid_idmag *mag)
+{
+ struct vfat_super_block *vs;
+ struct msdos_super_block *ms;
+ const unsigned char *vol_label = 0;
+ unsigned char *vol_serno = NULL, vol_label_buf[11];
+ uint16_t sector_size = 0, reserved;
+ uint32_t cluster_count, fat_size;
+ const char *version = NULL;
ms = blkid_probe_get_sb(pr, mag, struct msdos_super_block);
if (!ms)
- return -1;
-
- /* sector size check */
- if (!blkid_fat_valid_sectorsize(ms, §or_size))
+ return 0;
+ vs = blkid_probe_get_sb(pr, mag, struct vfat_super_block);
+ if (!vs)
+ return 0;
+ if (!fat_valid_superblock(mag, ms, vs, &cluster_count, &fat_size))
return 1;
- tmp = (unsigned char *) &ms->ms_dir_entries;
- dir_entries = tmp[0] + (tmp[1] << 8);
+ sector_size = unaligned_le16(&ms->ms_sector_size);
reserved = le16_to_cpu(ms->ms_reserved);
- tmp = (unsigned char *) &ms->ms_sectors;
- sect_count = tmp[0] + (tmp[1] << 8);
- if (sect_count == 0)
- sect_count = le32_to_cpu(ms->ms_total_sect);
-
- fat_length = le16_to_cpu(ms->ms_fat_length);
- if (fat_length == 0)
- fat_length = le32_to_cpu(vs->vs_fat32_length);
-
- fat_size = fat_length * ms->ms_fats;
- dir_size = ((dir_entries * sizeof(struct vfat_dir_entry)) +
- (sector_size-1)) / sector_size;
-
- cluster_count = sect_count - (reserved + fat_size + dir_size);
- if (ms->ms_cluster_size == 0)
- return 1;
- cluster_count /= ms->ms_cluster_size;
-
- if (cluster_count > FAT32_MAX)
- return 1;
if (ms->ms_fat_length) {
/* the label may be an attribute in the root directory */
- root_start = (reserved + fat_size) * sector_size;
- root_dir_entries = vs->vs_dir_entries[0] +
- (vs->vs_dir_entries[1] << 8);
+ uint32_t root_start = (reserved + fat_size) * sector_size;
+ uint32_t root_dir_entries = unaligned_le16(&vs->vs_dir_entries);
vol_label = search_fat_label(pr, root_start, root_dir_entries);
if (vol_label) {
version = "FAT12";
else if (cluster_count < FAT16_MAX)
version = "FAT16";
- } else {
+
+ } else if (vs->vs_fat32_length) {
unsigned char *buf;
uint16_t fsinfo_sect;
+ int maxloop = 100;
/* Search the FAT32 root dir for the label attribute */
- buf_size = vs->vs_cluster_size * sector_size;
- start_data_sect = reserved + fat_size;
+ uint32_t buf_size = vs->vs_cluster_size * sector_size;
+ uint32_t start_data_sect = reserved + fat_size;
+ uint32_t next = le32_to_cpu(vs->vs_root_cluster);
- version = "FAT32";
-
- next = le32_to_cpu(vs->vs_root_cluster);
while (next && --maxloop) {
uint32_t next_sect_off;
uint64_t next_off, fat_entry_off;
next = le32_to_cpu(*((uint32_t *) buf) & 0x0fffffff);
}
+ version = "FAT32";
+
if (!vol_label || !memcmp(vol_label, no_name, 11))
vol_label = vs->vs_label;
vol_serno = vs->vs_serno;
blkid_probe_set_label(pr, (unsigned char *) vol_label, 11);
/* We can't just print them as %04X, because they are unaligned */
- blkid_probe_sprintf_uuid(pr, vol_serno, 4, "%02X%02X-%02X%02X",
- vol_serno[3], vol_serno[2], vol_serno[1], vol_serno[0]);
-
+ if (vol_serno)
+ blkid_probe_sprintf_uuid(pr, vol_serno, 4, "%02X%02X-%02X%02X",
+ vol_serno[3], vol_serno[2], vol_serno[1], vol_serno[0]);
if (version)
blkid_probe_set_version(pr, version);
projects / util-linux / commitdiff