fileio.h

该工程是从ecos嵌入式系统下移植过来的一个小型的fat16文件系统

    _name,                                                      \
    _fsname,                                                    \
    _devname,                                                   \
    _data,                                                      \
    false,                                                      \
    NULL,                                                       \
    CYG_DIR_NULL                                                \
};

//=============================================================================
// IO vector descriptors

struct CYG_IOVEC_TAG
{
    void           *iov_base;           /* Base address. */
    ssize_t        iov_len;             /* Length. */
};

enum	cyg_uio_rw { UIO_READ, UIO_WRITE };

/* Segment flag values. */
enum cyg_uio_seg
{
    UIO_USERSPACE,		        /* from user data space */
    UIO_SYSSPACE		        /* from system space */
};

struct CYG_UIO_TAG
{
    struct CYG_IOVEC_TAG *uio_iov;	/* pointer to array of iovecs */
    int	                 uio_iovcnt;	/* number of iovecs in array */
    off_t       	 uio_offset;	/* offset into file this uio corresponds to */
    ssize_t     	 uio_resid;	/* residual i/o count */
    enum cyg_uio_seg     uio_segflg;    /* see above */
    enum cyg_uio_rw      uio_rw;        /* see above */
};

// Limits
#define UIO_SMALLIOV	8		/* 8 on stack, else malloc */

//=============================================================================
// Description of open file

typedef int cyg_fileop_read (struct CYG_FILE_TAG *fp, struct CYG_UIO_TAG *uio,unsigned int *uiType);
//typedef cyg_fileop_readwrite cyg_fileop_read;
typedef int cyg_fileop_write (struct CYG_FILE_TAG *fp, struct CYG_UIO_TAG *uio);
//typedef cyg_fileop_readwrite cyg_fileop_write;
typedef int cyg_fileop_lseek   (struct CYG_FILE_TAG *fp, off_t *pos, int whence );
typedef int cyg_fileop_ioctl   (struct CYG_FILE_TAG *fp, CYG_ADDRWORD com,
                                CYG_ADDRWORD data);
typedef cyg_bool cyg_fileop_select  (struct CYG_FILE_TAG *fp, int which, CYG_ADDRWORD info);
typedef int cyg_fileop_fsync   (struct CYG_FILE_TAG *fp, int mode );        
typedef int cyg_fileop_close   (struct CYG_FILE_TAG *fp);
typedef int cyg_fileop_fstat   (struct CYG_FILE_TAG *fp, struct stat *buf );
typedef int cyg_fileop_getinfo (struct CYG_FILE_TAG *fp, int key, void *buf, int len );
typedef int cyg_fileop_setinfo (struct CYG_FILE_TAG *fp, int key, void *buf, int len );

struct CYG_FILEOPS_TAG
{
    cyg_fileop_read     *fo_read;
    cyg_fileop_write    *fo_write;
    cyg_fileop_lseek    *fo_lseek;
    cyg_fileop_ioctl    *fo_ioctl;
    cyg_fileop_select   *fo_select;
    cyg_fileop_fsync    *fo_fsync;
    cyg_fileop_close    *fo_close;
    cyg_fileop_fstat    *fo_fstat;
    cyg_fileop_getinfo  *fo_getinfo;
    cyg_fileop_setinfo  *fo_setinfo;
};
//以下这个结构就是一个file结构
struct CYG_FILE_TAG
{
    cyg_uint32	                f_flag;		/* file state                   */
    cyg_uint16                  f_ucount;       /* use count                    */
    cyg_uint16                  f_type;		/* descriptor type              */
    cyg_uint32                  f_syncmode;     /* synchronization protocol     */
    struct CYG_FILEOPS_TAG      *f_ops;         /* file operations              */
    off_t       	        f_offset;       /* current offset               */
    CYG_ADDRWORD	        f_data;		/* file or socket               */
    CYG_ADDRWORD                f_xops;         /* extra type specific ops      */
    cyg_mtab_entry              *f_mte;         /* mount table entry            */
};

//-----------------------------------------------------------------------------
// File flags

// Allocation here is that bits 0..15 are copies of bits from the open
// flags, bits 16..23 are extra bits that are visible to filesystems but
// are not derived from the open call, and bits 24..31 are reserved for
// the fileio infrastructure.
#define CYG_FREAD       O_RDONLY
#define CYG_FWRITE      O_WRONLY
#define CYG_FNONBLOCK   O_NONBLOCK
#define CYG_FAPPEND     O_APPEND
#define CYG_FASYNC      0x00010000
#define CYG_FDIR        0x00020000

#define CYG_FLOCKED     0x01000000  // Set if file is locked
#define CYG_FLOCK       0x02000000  // Lock during file ops
#define CYG_FALLOC      0x80000000  // File is "busy", i.e. allocated

// Mask for open mode bits stored in file object
#define CYG_FILE_MODE_MASK (CYG_FREAD|CYG_FWRITE|CYG_FNONBLOCK|CYG_FAPPEND)

//-----------------------------------------------------------------------------
// Type of file

#define	CYG_FILE_TYPE_FILE      1	/* file */
#define	CYG_FILE_TYPE_SOCKET	2	/* communications endpoint */
#define	CYG_FILE_TYPE_DEVICE	3	/* device */

//-----------------------------------------------------------------------------
// Keys for getinf() and setinfo()

#define FILE_INFO_CONF          1       /* fpathconf() */

//-----------------------------------------------------------------------------
// Modes for fsync()

#define CYG_FSYNC              1
#define CYG_FDATASYNC          2

//-----------------------------------------------------------------------------
// Get/set info buffer structures

// This is used for pathconf() and fpathconf()
struct cyg_pathconf_info
{
    int         name;           // POSIX defined variable name
    long        value;          // Returned variable value
};

//=============================================================================
// Synchronization modes
// These values are filled into the syncmode fields of the above structures
// and define the synchronization protocol used when accessing the object in
// question.

#define CYG_SYNCMODE_NONE               (0)     // no locking required

#define CYG_SYNCMODE_FILE_FILESYSTEM    0x0002  // lock fs during file ops
#define CYG_SYNCMODE_FILE_MOUNTPOINT    0x0004  // lock mte during file ops
#define CYG_SYNCMODE_IO_FILE            0x0010  // lock file during io ops
#define CYG_SYNCMODE_IO_FILESYSTEM      0x0020  // lock fs during io ops
#define CYG_SYNCMODE_IO_MOUNTPOINT      0x0040  // lock mte during io ops
#define CYG_SYNCMODE_SOCK_FILE          0x0100  // lock socket during socket ops
#define CYG_SYNCMODE_SOCK_NETSTACK      0x0800  // lock netstack during socket ops

#define CYG_SYNCMODE_IO_SHIFT           (4)     // shift for IO to file bits
#define CYG_SYNCMODE_SOCK_SHIFT         (8)     // shift for sock to file bits

//=============================================================================
// Mount and umount functions

//__externC int mount( const char *devname,
 //                    const char *dir,
 //                    const char *fsname);

//__externC int umount( const char *name);

//=============================================================================
// Get/Set info functions

//__externC int cyg_fs_getinfo( const char *path, int key, void *buf, int len );
//__externC int cyg_fs_setinfo( const char *path, int key, void *buf, int len );
//__externC int cyg_fs_fgetinfo( int fd, int key, void *buf, int len );
//__externC int cyg_fs_fsetinfo( int fd, int key, void *buf, int len );

//=============================================================================
// Select support

//-----------------------------------------------------------------------------
// Data structure for embedding in client data structures. A pointer to this
// must be passed to cyg_selrecord() and cyg_selwakeup().

struct CYG_SELINFO_TAG
{
    CYG_ADDRWORD        si_info;        // info passed through from fo_select()
    CYG_ADDRESS         si_thread;      // selecting thread pointer
};

//-----------------------------------------------------------------------------
// Select support functions.

// cyg_selinit() is used to initialize a selinfo structure.
//__externC void cyg_selinit( struct CYG_SELINFO_TAG *sip );

// cyg_selrecord() is called when a client device needs to register
// the current thread for selection.
//__externC void cyg_selrecord( CYG_ADDRWORD info, struct CYG_SELINFO_TAG *sip );

// cyg_selwakeup() is called when the client device matches the select
// criterion, and needs to wake up a selector.
//__externC void cyg_selwakeup( struct CYG_SELINFO_TAG *sip );

//=============================================================================
// Timestamp support

// Provides the current time as a time_t timestamp for use in filesystem
// data strucures.

//__externC time_t cyg_timestamp(void);

//=============================================================================
// Default functions.
// Cast to the appropriate type, these functions can be put into any of
// the operation table slots to provide the defined error code.

//__externC int cyg_fileio_enosys(void);
//__externC int cyg_fileio_erofs(void);
//__externC int cyg_fileio_enoerr(void);
//__externC int cyg_fileio_enotdir(void);
//__externC cyg_fileop_select cyg_fileio_seltrue;

//-----------------------------------------------------------------------------
#endif // ifndef CYGONCE_FILEIO_H
// End of fileio.h