_name,                                                      \    _fsname,                                                    \    _devname,                                                   \    _data,                                                      \    false,                                                      \    NULL,                                                       \    CYG_DIR_NULL                                                \};//=============================================================================// IO vector descriptorsstruct 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 filetypedef 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;};//以下這個結構就是一個file結構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