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u-boot/include/fat.h
Aaron Williams 1d90c3b457 fat: fix FAT sector offsets overflow on large FAT partitions 
This patch fixes several issues where sector offsets can overflow due
to being limited to 16-bits. The cases where an overflow can happen
when accessing large FAT32 partitions are:

 - length of FAT in sectors
 - start sector of root directory
 - the sector of the first cluster

These issues were observed when reading files from a 64GB FAT32
filesystem.

Signed-off-by: Aaron Williams <aaron.williams@caviumnetworks.com>
Tested-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
2012-05-22 10:14:05 +02:00

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/*
* R/O (V)FAT 12/16/32 filesystem implementation by Marcus Sundberg
*
* 2002-07-28 - rjones@nexus-tech.net - ported to ppcboot v1.1.6
* 2003-03-10 - kharris@nexus-tech.net - ported to u-boot
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*
*/
#ifndef _FAT_H_
#define _FAT_H_
#include <asm/byteorder.h>
#define CONFIG_SUPPORT_VFAT
/* Maximum Long File Name length supported here is 128 UTF-16 code units */
#define VFAT_MAXLEN_BYTES 256 /* Maximum LFN buffer in bytes */
#define VFAT_MAXSEQ 9 /* Up to 9 of 13 2-byte UTF-16 entries */
#define PREFETCH_BLOCKS 2
#define MAX_CLUSTSIZE 65536
#define DIRENTSPERBLOCK (mydata->sect_size / sizeof(dir_entry))
#define DIRENTSPERCLUST ((mydata->clust_size * mydata->sect_size) / \
sizeof(dir_entry))
#define FATBUFBLOCKS 6
#define FATBUFSIZE (mydata->sect_size * FATBUFBLOCKS)
#define FAT12BUFSIZE ((FATBUFSIZE*2)/3)
#define FAT16BUFSIZE (FATBUFSIZE/2)
#define FAT32BUFSIZE (FATBUFSIZE/4)
/* Filesystem identifiers */
#define FAT12_SIGN "FAT12 "
#define FAT16_SIGN "FAT16 "
#define FAT32_SIGN "FAT32 "
#define SIGNLEN 8
/* File attributes */
#define ATTR_RO 1
#define ATTR_HIDDEN 2
#define ATTR_SYS 4
#define ATTR_VOLUME 8
#define ATTR_DIR 16
#define ATTR_ARCH 32
#define ATTR_VFAT (ATTR_RO | ATTR_HIDDEN | ATTR_SYS | ATTR_VOLUME)
#define DELETED_FLAG ((char)0xe5) /* Marks deleted files when in name[0] */
#define aRING 0x05 /* Used as special character in name[0] */
/*
* Indicates that the entry is the last long entry in a set of long
* dir entries
*/
#define LAST_LONG_ENTRY_MASK 0x40
/* Flags telling whether we should read a file or list a directory */
#define LS_NO 0
#define LS_YES 1
#define LS_DIR 1
#define LS_ROOT 2
#define ISDIRDELIM(c) ((c) == '/' || (c) == '\\')
#define FSTYPE_NONE (-1)
#if defined(__linux__) && defined(__KERNEL__)
#define FAT2CPU16 le16_to_cpu
#define FAT2CPU32 le32_to_cpu
#else
#if __LITTLE_ENDIAN
#define FAT2CPU16(x) (x)
#define FAT2CPU32(x) (x)
#else
#define FAT2CPU16(x) ((((x) & 0x00ff) << 8) | (((x) & 0xff00) >> 8))
#define FAT2CPU32(x) ((((x) & 0x000000ff) << 24) | \
(((x) & 0x0000ff00) << 8) | \
(((x) & 0x00ff0000) >> 8) | \
(((x) & 0xff000000) >> 24))
#endif
#endif
#define TOLOWER(c) if((c) >= 'A' && (c) <= 'Z'){(c)+=('a' - 'A');}
#define TOUPPER(c) if ((c) >= 'a' && (c) <= 'z') \
(c) -= ('a' - 'A');
#define START(dent) (FAT2CPU16((dent)->start) \
+ (mydata->fatsize != 32 ? 0 : \
(FAT2CPU16((dent)->starthi) << 16)))
#define CHECK_CLUST(x, fatsize) ((x) <= 1 || \
(x) >= ((fatsize) != 32 ? 0xfff0 : 0xffffff0))
typedef struct boot_sector {
__u8 ignored[3]; /* Bootstrap code */
char system_id[8]; /* Name of fs */
__u8 sector_size[2]; /* Bytes/sector */
__u8 cluster_size; /* Sectors/cluster */
__u16 reserved; /* Number of reserved sectors */
__u8 fats; /* Number of FATs */
__u8 dir_entries[2]; /* Number of root directory entries */
__u8 sectors[2]; /* Number of sectors */
__u8 media; /* Media code */
__u16 fat_length; /* Sectors/FAT */
__u16 secs_track; /* Sectors/track */
__u16 heads; /* Number of heads */
__u32 hidden; /* Number of hidden sectors */
__u32 total_sect; /* Number of sectors (if sectors == 0) */
/* FAT32 only */
__u32 fat32_length; /* Sectors/FAT */
__u16 flags; /* Bit 8: fat mirroring, low 4: active fat */
__u8 version[2]; /* Filesystem version */
__u32 root_cluster; /* First cluster in root directory */
__u16 info_sector; /* Filesystem info sector */
__u16 backup_boot; /* Backup boot sector */
__u16 reserved2[6]; /* Unused */
} boot_sector;
typedef struct volume_info
{
__u8 drive_number; /* BIOS drive number */
__u8 reserved; /* Unused */
__u8 ext_boot_sign; /* 0x29 if fields below exist (DOS 3.3+) */
__u8 volume_id[4]; /* Volume ID number */
char volume_label[11]; /* Volume label */
char fs_type[8]; /* Typically FAT12, FAT16, or FAT32 */
/* Boot code comes next, all but 2 bytes to fill up sector */
/* Boot sign comes last, 2 bytes */
} volume_info;
typedef struct dir_entry {
char name[8],ext[3]; /* Name and extension */
__u8 attr; /* Attribute bits */
__u8 lcase; /* Case for base and extension */
__u8 ctime_ms; /* Creation time, milliseconds */
__u16 ctime; /* Creation time */
__u16 cdate; /* Creation date */
__u16 adate; /* Last access date */
__u16 starthi; /* High 16 bits of cluster in FAT32 */
__u16 time,date,start;/* Time, date and first cluster */
__u32 size; /* File size in bytes */
} dir_entry;
typedef struct dir_slot {
__u8 id; /* Sequence number for slot */
__u8 name0_4[10]; /* First 5 characters in name */
__u8 attr; /* Attribute byte */
__u8 reserved; /* Unused */
__u8 alias_checksum;/* Checksum for 8.3 alias */
__u8 name5_10[12]; /* 6 more characters in name */
__u16 start; /* Unused */
__u8 name11_12[4]; /* Last 2 characters in name */
} dir_slot;
/*
* Private filesystem parameters
*
* Note: FAT buffer has to be 32 bit aligned
* (see FAT32 accesses)
*/
typedef struct {
__u8 *fatbuf; /* Current FAT buffer */
int fatsize; /* Size of FAT in bits */
__u32 fatlength; /* Length of FAT in sectors */
__u16 fat_sect; /* Starting sector of the FAT */
__u32 rootdir_sect; /* Start sector of root directory */
__u16 sect_size; /* Size of sectors in bytes */
__u16 clust_size; /* Size of clusters in sectors */
int data_begin; /* The sector of the first cluster, can be negative */
int fatbufnum; /* Used by get_fatent, init to -1 */
} fsdata;
typedef int (file_detectfs_func)(void);
typedef int (file_ls_func)(const char *dir);
typedef long (file_read_func)(const char *filename, void *buffer,
unsigned long maxsize);
struct filesystem {
file_detectfs_func *detect;
file_ls_func *ls;
file_read_func *read;
const char name[12];
};
/* FAT tables */
file_detectfs_func file_fat_detectfs;
file_ls_func file_fat_ls;
file_read_func file_fat_read;
/* Currently this doesn't check if the dir exists or is valid... */
int file_cd(const char *path);
int file_fat_detectfs(void);
int file_fat_ls(const char *dir);
long file_fat_read(const char *filename, void *buffer, unsigned long maxsize);
const char *file_getfsname(int idx);
int fat_register_device(block_dev_desc_t *dev_desc, int part_no);
int file_fat_write(const char *filename, void *buffer, unsigned long maxsize);
#endif /* _FAT_H_ */
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