fs_fat32.h

這是一個實時嵌入式作業系統 實作了MCS51 ARM等MCU

# define FSI_GETSTRUCTSIG(p)       fat_getuint32(UBYTE_PTR(p,FSI_STRUCTSIG))
# define FSI_GETFREECOUNT(p)       fat_getuint32(UBYTE_PTR(p,FSI_FREECOUNT))
# define FSI_GETNXTFREE(p)         fat_getuint32(UBYTE_PTR(p,FSI_NXTFREE))
# define FSI_GETTRAILSIG(p)        fat_getuint32(UBYTE_PTR(p,FSI_TRAILSIG))

# define DIR_GETCRTIME(p)          fat_getuint16(UBYTE_PTR(p,DIR_CRTIME))
# define DIR_GETCRDATE(p)          fat_getuint16(UBYTE_PTR(p,DIR_CRDATE))
# define DIR_GETLASTACCDATE(p)     fat_getuint16(UBYTE_PTR(p,DIR_LASTACCDATE))
# define DIR_GETFSTCLUSTHI(p)      fat_getuint16(UBYTE_PTR(p,DIR_FSTCLUSTHI))
# define DIR_GETWRTTIME(p)         fat_getuint16(UBYTE_PTR(p,DIR_WRTTIME))
# define DIR_GETWRTDATE(p)         fat_getuint16(UBYTE_PTR(p,DIR_WRTDATE))
# define DIR_GETFSTCLUSTLO(p)      fat_getuint16(UBYTE_PTR(p,DIR_FSTCLUSTLO))
# define DIR_GETFILESIZE(p)        fat_getuint32(UBYTE_PTR(p,DIR_FILESIZE))

# define FSI_GETLEADSIG(p)         fat_getuint32(UBYTE_PTR(p,FSI_LEADSIG))
# define FSI_GETSTRUCTSIG(p)       fat_getuint32(UBYTE_PTR(p,FSI_STRUCTSIG))
# define FSI_GETFREECOUNT(p)       fat_getuint32(UBYTE_PTR(p,FSI_FREECOUNT))
# define FSI_GETNXTFREE(p)         fat_getuint32(UBYTE_PTR(p,FSI_NXTFREE))
# define FSI_GETTRAILSIG(p)        fat_getuint32(UBYTE_PTR(p,FSI_TRAILSIG))

# define FAT_GETFAT16(p,i)         fat_getuint16(UBYTE_PTR(p,i))
# define FAT_GETFAT32(p,i)         fat_getuint32(UBYTE_PTR(p,i))

# define MBR_PUTRESVDSECCOUNT(p,v) fat_putuint16(UBYTE_PTR(p,BS_RESVDSECCOUNT,v))
# define MBR_PUTFATSZ16(p,v)       fat_putuint16(UBYTE_PTR(p,BS_FATSZ16,v))
# define MBR_PUTSECPERTRK(p,v)     fat_putuint16(UBYTE_PTR(p,BS_SECPERTRK,v))
# define MBR_PUTNUMHEADS(p,v)      fat_putuint16(UBYTE_PTR(p,BS_NUMHEADS,v))
# define MBR_PUTHIDSEC(p,v)        fat_putuint32(UBYTE_PTR(p,BS_HIDSEC,v))
# define MBR_PUTTOTSEC32(p,v)      fat_putuint32(UBYTE_PTR(p,BS_TOTSEC32,v))
# define MBR_PUTFATSZ32(p,v)       fat_putuint32(UBYTE_PTR(p,BS32_FATSZ32,v))
# define MBR_PUTEXTFLAGS(p,v)      fat_putuint16(UBYTE_PTR(p,BS32_EXTFLAGS,v))
# define MBR_PUTFSVER(p,v)         fat_putuint16(UBYTE_PTR(p,BS32_FSVER,v))
# define MBR_PUTROOTCLUS(p,v)      fat_putuint32(UBYTE_PTR(p,BS32_ROOTCLUS,v))
# define MBR_PUTFSINFO(p,v)        fat_putuint16(UBYTE_PTR(p,BS32_FSINFO,v))
# define MBR_PUTBKBOOTSEC(p,v)     fat_putuint16(UBYTE_PTR(p,BS32_BKBOOTSEC,v))
# define MBR_PUTSIGNATURE(p,v)     fat_getuint16(UBYTE_PTR(p,BS_SIGNATURE),v)

# define FSI_PUTLEADSIG(p,v)       fat_putuint32(UBYTE_PTR(p,FSI_LEADSIG),v)
# define FSI_PUTSTRUCTSIG(p,v)     fat_putuint32(UBYTE_PTR(p,FSI_STRUCTSIG),v)
# define FSI_PUTFREECOUNT(p,v)     fat_putuint32(UBYTE_PTR(p,FSI_FREECOUNT),v)
# define FSI_PUTNXTFREE(p,v)       fat_putuint32(UBYTE_PTR(p,FSI_NXTFREE),v)
# define FSI_PUTTRAILSIG(p,v)      fat_putuint32(UBYTE_PTR(p,FSI_TRAILSIG),v)

# define DIR_PUTCRTIME(p,v)        fat_putuint16(UBYTE_PTR(p,DIR_CRTIME),v)
# define DIR_PUTCRDATE(p,v)        fat_putuint16(UBYTE_PTR(p,DIR_CRDATE),v)
# define DIR_PUTLASTACCDATE(p,v)   fat_putuint16(UBYTE_PTR(p,DIR_LASTACCDATE),v)
# define DIR_PUTFSTCLUSTHI(p,v)    fat_putuint16(UBYTE_PTR(p,DIR_FSTCLUSTHI),v)
# define DIR_PUTWRTTIME(p,v)       fat_putuint16(UBYTE_PTR(p,DIR_WRTTIME),v)
# define DIR_PUTWRTDATE(p,v)       fat_putuint16(UBYTE_PTR(p,DIR_WRTDATE),v)
# define DIR_PUTFSTCLUSTLO(p,v)    fat_putuint16(UBYTE_PTR(p,DIR_FSTCLUSTLO),v)
# define DIR_PUTFILESIZE(p,v)      fat_putuint32(UBYTE_PTR(p,DIR_FILESIZE),v)

# define FSI_PUTLEADSIG(p,v)       fat_putuint32(UBYTE_PTR(p,FSI_LEADSIG),v)
# define FSI_PUTSTRUCTSIG(p,v)     fat_putuint32(UBYTE_PTR(p,FSI_STRUCTSIG),v)
# define FSI_PUTFREECOUNT(p,v)     fat_putuint32(UBYTE_PTR(p,FSI_FREECOUNT),v)
# define FSI_PUTNXTFREE(p,v)       fat_putuint32(UBYTE_PTR(p,FSI_NXTFREE),v)
# define FSI_PUTTRAILSIG(p,v)      fat_putuint32(UBYTE_PTR(p,FSI_TRAILSIG),v)

# define FAT_PUTFAT16(p,i,v)       fat_putuint16(UBYTE_PTR(p,i),v)
# define FAT_PUTFAT32(p,i,v)       fat_putuint32(UBYTE_PTR(p,i),v)

#else

/* But nothing special has to be done for the little endian-case for access
 * to aligned mulitbyte values.
 */

# define MBR_GETRESVDSECCOUNT(p)   UINT16_VAL(p,BS_RESVDSECCOUNT)
# define MBR_GETFATSZ16(p)         UINT16_VAL(p,BS_FATSZ16)
# define MBR_GETSECPERTRK(p)       UINT16_VAL(p,BS_SECPERTRK)
# define MBR_GETNUMHEADS(p)        UINT16_VAL(p,BS_NUMHEADS)
# define MBR_GETHIDSEC(p)          UINT32_VAL(p,BS_HIDSEC)
# define MBR_GETTOTSEC32(p)        UINT32_VAL(p,BS_TOTSEC32)
# define MBR_GETFATSZ32(p)         UINT32_VAL(p,BS32_FATSZ32)
# define MBR_GETEXTFLAGS(p)        UINT16_VAL(p,BS32_EXTFLAGS)
# define MBR_GETFSVER(p)           UINT16_VAL(p,BS32_FSVER)
# define MBR_GETROOTCLUS(p)        UINT32_VAL(p,BS32_ROOTCLUS)
# define MBR_GETFSINFO(p)          UINT16_VAL(p,BS32_FSINFO)
# define MBR_GETBKBOOTSEC(p)       UINT16_VAL(p,BS32_BKBOOTSEC)
# define MBR_GETSIGNATURE(p)       UINT16_VAL(p,BS_SIGNATURE)

# define MBR_GETPARTSECTOR(s)      (*((uint32*)(s)))

# define FSI_GETLEADSIG(p)         UINT32_VAL(p,FSI_LEADSIG)
# define FSI_GETSTRUCTSIG(p)       UINT32_VAL(p,FSI_STRUCTSIG)
# define FSI_GETFREECOUNT(p)       UINT32_VAL(p,FSI_FREECOUNT)
# define FSI_GETNXTFREE(p)         UINT32_VAL(p,FSI_NXTFREE)
# define FSI_GETTRAILSIG(p)        UINT32_VAL(p,FSI_TRAILSIG)

# define DIR_GETCRTIME(p)          UINT16_VAL(p,DIR_CRTIME)
# define DIR_GETCRDATE(p)          UINT16_VAL(p,DIR_CRDATE)
# define DIR_GETLASTACCDATE(p)     UINT16_VAL(p,DIR_LASTACCDATE)
# define DIR_GETFSTCLUSTHI(p)      UINT16_VAL(p,DIR_FSTCLUSTHI)
# define DIR_GETWRTTIME(p)         UINT16_VAL(p,DIR_WRTTIME)
# define DIR_GETWRTDATE(p)         UINT16_VAL(p,DIR_WRTDATE)
# define DIR_GETFSTCLUSTLO(p)      UINT16_VAL(p,DIR_FSTCLUSTLO)
# define DIR_GETFILESIZE(p)        UINT32_VAL(p,DIR_FILESIZE)

# define FSI_GETLEADSIG(p)         UINT32_VAL(p,FSI_LEADSIG)
# define FSI_GETSTRUCTSIG(p)       UINT32_VAL(p,FSI_STRUCTSIG)
# define FSI_GETFREECOUNT(p)       UINT32_VAL(p,FSI_FREECOUNT)
# define FSI_GETNXTFREE(p)         UINT32_VAL(p,FSI_NXTFREE)
# define FSI_GETTRAILSIG(p)        UINT32_VAL(p,FSI_TRAILSIG)

# define FAT_GETFAT16(p,i)         UINT16_VAL(p,i)
# define FAT_GETFAT32(p,i)         UINT32_VAL(p,i)

# define MBR_PUTRESVDSECCOUNT(p,v) UINT16_PUT(p,BS_RESVDSECCOUNT,v)
# define MBR_PUTFATSZ16(p,v)       UINT16_PUT(p,BS_FATSZ16,v)
# define MBR_PUTSECPERTRK(p,v)     UINT16_PUT(p,BS_SECPERTRK,v)
# define MBR_PUTNUMHEADS(p,v)      UINT16_PUT(p,BS_NUMHEADS,v)
# define MBR_PUTHIDSEC(p,v)        UINT32_PUT(p,BS_HIDSEC,v)
# define MBR_PUTTOTSEC32(p,v)      UINT32_PUT(p,BS_TOTSEC32,v)
# define MBR_PUTFATSZ32(p,v)       UINT32_PUT(p,BS32_FATSZ32,v)
# define MBR_PUTEXTFLAGS(p,v)      UINT16_PUT(p,BS32_EXTFLAGS,v)
# define MBR_PUTFSVER(p,v)         UINT16_PUT(p,BS32_FSVER,v)
# define MBR_PUTROOTCLUS(p,v)      UINT32_PUT(p,BS32_ROOTCLUS,v)
# define MBR_PUTFSINFO(p,v)        UINT16_PUT(p,BS32_FSINFO,v)
# define MBR_PUTBKBOOTSEC(p,v)     UINT16_PUT(p,BS32_BKBOOTSEC,v)
# define MBR_PUTSIGNATURE(p,v)     UINT16_PUT(p,BS_SIGNATURE,v)

# define FSI_PUTLEADSIG(p,v)       UINT32_PUT(p,FSI_LEADSIG,v)
# define FSI_PUTSTRUCTSIG(p,v)     UINT32_PUT(p,FSI_STRUCTSIG,v)
# define FSI_PUTFREECOUNT(p,v)     UINT32_PUT(p,FSI_FREECOUNT,v)
# define FSI_PUTNXTFREE(p,v)       UINT32_PUT(p,FSI_NXTFREE,v)
# define FSI_PUTTRAILSIG(p,v)      UINT32_PUT(p,FSI_TRAILSIG,v)

# define DIR_PUTCRTIME(p,v)        UINT16_PUT(p,DIR_CRTIME,v)
# define DIR_PUTCRDATE(p,v)        UINT16_PUT(p,DIR_CRDATE,v)
# define DIR_PUTLASTACCDATE(p,v)   UINT16_PUT(p,DIR_LASTACCDATE,v)
# define DIR_PUTFSTCLUSTHI(p,v)    UINT16_PUT(p,DIR_FSTCLUSTHI,v)
# define DIR_PUTWRTTIME(p,v)       UINT16_PUT(p,DIR_WRTTIME,v)
# define DIR_PUTWRTDATE(p,v)       UINT16_PUT(p,DIR_WRTDATE,v)
# define DIR_PUTFSTCLUSTLO(p,v)    UINT16_PUT(p,DIR_FSTCLUSTLO,v)
# define DIR_PUTFILESIZE(p,v)      UINT32_PUT(p,DIR_FILESIZE,v)

# define FSI_PUTLEADSIG(p,v)       UINT32_PUT(p,FSI_LEADSIG,v)
# define FSI_PUTSTRUCTSIG(p,v)     UINT32_PUT(p,FSI_STRUCTSIG,v)
# define FSI_PUTFREECOUNT(p,v)     UINT32_PUT(p,FSI_FREECOUNT,v)
# define FSI_PUTNXTFREE(p,v)       UINT32_PUT(p,FSI_NXTFREE,v)
# define FSI_PUTTRAILSIG(p,v)      UINT32_PUT(p,FSI_TRAILSIG,v)

# define FAT_PUTFAT16(p,i,v)       UINT16_PUT(p,i,v)
# define FAT_PUTFAT32(p,i,v)       UINT32_PUT(p,i,v)

#endif

/****************************************************************************
 * Public Types
 ****************************************************************************/

/* This structure represents the overall mountpoint state.  An instance of this
 * structure is retained as inode private data on each mountpoint that is
 * mounted with a fat32 filesystem.
 */

struct fat_file_s;
struct fat_mountpt_s
{
  struct inode      *fs_blkdriver; /* The block driver inode that hosts the FAT32 fs */
  struct fat_file_s *fs_head;      /* A list to all files opened on this mountpoint */

  sem_t    fs_sem;                 /* Used to assume thread-safe access */
  size_t   fs_hwsectorsize;        /* HW: Sector size reported by block driver*/
  size_t   fs_hwnsectors;          /* HW: The number of sectors reported by the hardware */
  size_t   fs_fatbase;             /* Logical block of start of filesystem (past resd sectors) */
  size_t   fs_rootbase;            /* MBR: Cluster no. of 1st cluster of root dir */
  size_t   fs_database;            /* Logical block of start data sectors */
  size_t   fs_fsinfo;              /* MBR: Sector number of FSINFO sector */
  size_t   fs_currentsector;       /* The sector number buffered in fs_buffer */
  uint32   fs_nclusters;           /* Maximum number of data clusters */
  uint32   fs_nfatsects;           /* MBR: Count of sectors occupied by one fat */
  uint32   fs_fattotsec;           /* MBR: Total count of sectors on the volume */
  uint32   fs_fsifreecount;        /* FSI: Last free cluster count on volume */
  uint32   fs_fsinextfree;         /* FSI: Cluster number of 1st free cluster */
  uint16   fs_fatresvdseccount;    /* MBR: The total number of reserved sectors */
  uint16   fs_rootentcnt;          /* MBR: Count of 32-bit root directory entries */
  boolean  fs_mounted;             /* TRUE: The file system is ready */
  boolean  fs_dirty;               /* TRUE: fs_buffer is dirty */
  boolean  fs_fsidirty;            /* TRUE: FSINFO sector must be written to disk */
  ubyte    fs_type;                /* FSTYPE_FAT12, FSTYPE_FAT16, or FSTYPE_FAT32 */
  ubyte    fs_fatnumfats;          /* MBR: Number of FATs (probably 2) */
  ubyte    fs_fatsecperclus;       /* MBR: Sectors per allocation unit: 2**n, n=0..7 */
  ubyte   *fs_buffer;              /* This is an allocated buffer to hold one sector
                                    * from the device */
};

/* This structure represents on open file under the mountpoint.  An instance
 * of this structure is retained as struct file specific information on each
 * opened file.
 */

struct fat_file_s
{
  struct fat_file_s *ff_next;      /* Retained in a singly linked list */
  boolean  ff_open;                /* TRUE: The file is (still) open */
  ubyte    ff_bflags;              /* The file buffer flags */
  ubyte    ff_oflags;              /* Flags provided when file was opened */
  ubyte    ff_sectorsincluster;    /* Sectors remaining in cluster */
  uint16   ff_dirindex;            /* Index into ff_dirsector to directory entry */
  uint32   ff_currentcluster;      /* Current cluster being accessed */
  size_t   ff_dirsector;           /* Sector containing the directory entry */
  size_t   ff_position;            /* File position for read/write/seek in bytes */
  size_t   ff_size;                /* Size of the file in bytes */
  size_t   ff_startcluster;        /* Start cluster of file on media */
  size_t   ff_currentsector;       /* Current sector in the file buffer */
  ubyte   *ff_buffer;              /* File buffer (for partial sector accesses) */
};

/* This structure is used internally for describing directory entries */

struct fat_dirinfo_s
{
  ubyte    fd_name[8+3];           /* Filename -- directory format*/
#ifdef CONFIG_FAT_LCNAMES
  ubyte    fd_ntflags;             /* NTRes lower case flags */
#endif
  struct fs_fatdir_s dir;        /* Used with opendir, readdir, etc. */
  ubyte   *fd_entry;               /* A pointer to the raw 32-byte entry */
};

/****************************************************************************
 * Global Variables
 ****************************************************************************/

/****************************************************************************
 * Public Function Prototypes
 ****************************************************************************/

#undef EXTERN
#if defined(__cplusplus)
#define EXTERN extern "C"
extern "C" {
#else
#define EXTERN extern
#endif

/* Utitilies to handle unaligned or byte swapped accesses */

EXTERN uint16 fat_getuint16(ubyte *ptr);
EXTERN uint32 fat_getuint32(ubyte *ptr);
EXTERN void   fat_putuint16(ubyte *ptr, uint16 value16);
EXTERN void   fat_putuint32(ubyte *ptr, uint32 value32);

/* Manage the per-mount semaphore that protects access to shared resources */

EXTERN void   fat_semtake(struct fat_mountpt_s *fs);
EXTERN void   fat_semgive(struct fat_mountpt_s *fs);

/* Get the current time for FAT creation and write times */

EXTERN uint32 fat_systime2fattime(void);
EXTERN time_t fat_fattime2systime(uint16 time, uint16 date);

/* Handle hardware interactions for mounting */

EXTERN int    fat_mount(struct fat_mountpt_s *fs, boolean writeable);
EXTERN int    fat_checkmount(struct fat_mountpt_s *fs);

/* low-level hardware access */

EXTERN int    fat_hwread(struct fat_mountpt_s *fs, ubyte *buffer,
                         size_t sector, unsigned int nsectors);
EXTERN int    fat_hwwrite(struct fat_mountpt_s *fs, ubyte *buffer,
                          size_t sector, unsigned int nsectors);

/* Cluster / cluster chain access helpers */

EXTERN ssize_t fat_cluster2sector(struct fat_mountpt_s *fs,  uint32 cluster );
EXTERN ssize_t fat_getcluster(struct fat_mountpt_s *fs, uint32 clusterno);
EXTERN int    fat_putcluster(struct fat_mountpt_s *fs, uint32 clusterno,
                             size_t startsector);
EXTERN int    fat_removechain(struct fat_mountpt_s *fs, uint32 cluster);
EXTERN sint32 fat_extendchain(struct fat_mountpt_s *fs, uint32 cluster);

#define fat_createchain(fs) fat_extendchain(fs, 0)

/* Help for traversing directory trees */

EXTERN int    fat_nextdirentry(struct fat_mountpt_s *fs, struct fs_fatdir_s *dir);
EXTERN int    fat_finddirentry(struct fat_mountpt_s *fs, struct fat_dirinfo_s *dirinfo,
                               const char *path);
EXTERN int    fat_allocatedirentry(struct fat_mountpt_s *fs, struct fat_dirinfo_s *dirinfo);

EXTERN int    fat_dirname2path(char *path, ubyte *direntry);

/* File creation and removal helpers */

EXTERN int    fat_dirtruncate(struct fat_mountpt_s *fs, struct fat_dirinfo_s *dirinfo);
EXTERN int    fat_dircreate(struct fat_mountpt_s *fs, struct fat_dirinfo_s *dirinfo);
EXTERN int    fat_remove(struct fat_mountpt_s *fs, const char *relpath, boolean directory);

/* Mountpoint and file buffer cache (for partial sector accesses) */

EXTERN int    fat_fscacheflush(struct fat_mountpt_s *fs);
EXTERN int    fat_fscacheread(struct fat_mountpt_s *fs, size_t sector);
EXTERN int    fat_ffcacheflush(struct fat_mountpt_s *fs, struct fat_file_s *ff);
EXTERN int    fat_ffcacheread(struct fat_mountpt_s *fs, struct fat_file_s *ff, size_t sector);
EXTERN int    fat_ffcacheinvalidate(struct fat_mountpt_s *fs, struct fat_file_s *ff);

/* FSINFO sector support */

EXTERN int fat_updatefsinfo(struct fat_mountpt_s *fs);
EXTERN int fat_nfreeclusters(struct fat_mountpt_s *fs, size_t *pfreeclusters);

#undef EXTERN
#if defined(__cplusplus)
}
#endif

#endif /* __FS_FAT_FS_FAT32_H */