fatfs.c

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

    if (err != ENOERR)
        return err;

    // Fill in the status
    buf->st_mode        = ds.node->mode;
    buf->st_ino         = (ino_t)ds.node->cluster;
    buf->st_dev         = 0;
    buf->st_nlink       = 1;
    buf->st_uid         = 0;
    buf->st_gid         = 0;
    buf->st_size        = ds.node->size;
    buf->st_atime       = ds.node->atime;
    buf->st_mtime       = ds.node->mtime;
    buf->st_ctime       = ds.node->ctime;

    return ENOERR;
}

// -------------------------------------------------------------------------
// fatfs_getinfo()
// Getinfo. Nothing to support here at present.

static int 
fatfs_getinfo(cyg_mtab_entry *mte, 
              cyg_dir         dir, 
              const char     *name,
              int             key, 
              void           *buf, 
              int             len)
{
    printf( "Getinfo mte=%p dir=%p name='%s' key=%d buf=%p len=%d",
                    mte, dir, name, key, buf, len);
    return EINVAL;
}

// -------------------------------------------------------------------------
// fatfs_setinfo()
// Setinfo. Nothing to support here at present.

static int 
fatfs_setinfo(cyg_mtab_entry *mte, 
              cyg_dir         dir, 
              const char     *name,
              int             key, 
              void           *buf, 
              int             len)
{
    printf( "Getinfo mte=%p dir=%p name='%s' key=%d buf=%p len=%d",
                    mte, dir, name, key, buf, len);
    return EINVAL;
}

//==========================================================================
// File operations

// -------------------------------------------------------------------------
// fatfs_fo_read()
// Read data from the file.

static int 
fatfs_fo_read(struct CYG_FILE_TAG *fp, struct CYG_UIO_TAG *uio)
{
    fatfs_disk_t *disk = (fatfs_disk_t *)fp->f_mte->data;
    fatfs_node_t *node = (fatfs_node_t *)fp->f_data;
    cyg_uint32 pos = fp->f_offset;
    ssize_t resid = uio->uio_resid;
    int i;

    printf( "Read fp=%p uio=%p pos=%d", fp, uio, pos);

    // Loop over the io vectors until there are none left
    for (i = 0; i < uio->uio_iovcnt; i++)
    {
        cyg_iovec *iov = &uio->uio_iov[i];
        char *buf = (char *)iov->iov_base;
        off_t len = iov->iov_len;

        // Loop over each vector filling it with data from the file.
        while (len > 0 && pos < node->size)
        {
            cyg_uint32 l = len;
            int err;

            // Adjust size to end of file if necessary
            if (l > node->size-pos)
                l = node->size-pos;

            // Read data
            err = fatfs_read_data(disk, node, buf, &l, pos);

            if (err != ENOERR)
                return err;

            // Update working vars
            len   -= l;
            buf   += l;
            pos   += l;
            resid -= l;
        }
    }

    // We successfully read some data,
    // update the access time, file offset and transfer residue.
    node->atime    = timeGetTime(); 
    uio->uio_resid = resid;
    fp->f_offset   = (off_t)pos;

    return ENOERR;
}

// -------------------------------------------------------------------------
// fatfs_fo_write()
// Write data to file.

static int 
fatfs_fo_write(struct CYG_FILE_TAG *fp, struct CYG_UIO_TAG *uio)
{
    fatfs_disk_t *disk = (fatfs_disk_t *)fp->f_mte->data;
    fatfs_node_t *node = (fatfs_node_t *)fp->f_data;
    cyg_uint32 pos = fp->f_offset;
    ssize_t resid = uio->uio_resid;
    int err = ENOERR;
    int i;

    printf( "Write fp=%p uio=%p pos=%d", fp, uio, pos);
    
    // If the APPEND mode bit was supplied, force all writes to
    // the end of the file.
    if (fp->f_flag & CYG_FAPPEND)
        pos = fp->f_offset = node->size;

    // Check that pos is within current file size, or at the very end.
    if (pos < 0 || pos > node->size)
        return EINVAL;
   
    // Now loop over the iovecs until they are all done, or
    // we get an error.
    for (i = 0; i < uio->uio_iovcnt; i++)
    {
        cyg_iovec *iov = &uio->uio_iov[i];
        char *buf = (char *)iov->iov_base;
        off_t len = iov->iov_len;
 
        // Loop over the vector writing it to the file until it has
        // all been done.
        while (len > 0)
        {
            cyg_uint32 l = len;

            // Write data
            err = fatfs_write_data(disk, node, buf, &l, pos);

            // Update working vars
            len   -= l;
            buf   += l;
            pos   += l;
            resid -= l;

            // Stop writing if there is no more space in the file and
            // indicate end of data.
            if (err == ENOSPC)
                break;
            
            if (err != ENOERR)
                return err;
        }
    }        

    // We wrote some data successfully, update the modified and access
    // times of the node, increase its size appropriately, and update
    // the file offset and transfer residue.
    node->mtime = 
    node->atime = timeGetTime();
    if (pos > node->size)
        node->size = pos;

    uio->uio_resid = resid;
    fp->f_offset = (off_t)pos;

    return err;
}

// -------------------------------------------------------------------------
// fatfs_fo_lseek()
// Seek to a new file position.

static int 
fatfs_fo_lseek(struct CYG_FILE_TAG *fp, off_t *apos, int whence)
{
    fatfs_node_t *node = (fatfs_node_t *)fp->f_data;
    off_t pos = *apos;

    printf( "Lseek fp=%p pos=%d whence=%d", fp, fp->f_offset, whence);

    switch (whence)
    {
        case SEEK_SET:
            // Pos is already where we want to be.
            break;
         case SEEK_CUR:
            // Add pos to current offset.
            pos += fp->f_offset;
            break;
         case SEEK_END:
            // Add pos to file size.
            pos += node->size;
            break;
         default:
            return EINVAL;
    }

    // Check that pos is still within current file size, or at the
    // very end.
    if (pos < 0 || pos > node->size)
        return EINVAL;
  
    // All OK, set fp offset and return new position.
    *apos = fp->f_offset = pos;

    printf("Lseek fp=%p new pos=%d", fp, *apos);

    return ENOERR;
}

// -------------------------------------------------------------------------
// fatfs_fo_ioctl()
// Handle ioctls. Currently none are defined.

static int 
fatfs_fo_ioctl(struct CYG_FILE_TAG *fp, CYG_ADDRWORD com, CYG_ADDRWORD data)
{
    printf( "Ioctl fp=%p com=%x data=%x", fp, com, data);
    return EINVAL;
}

// -------------------------------------------------------------------------
// fatfs_fo_fsync().
// Force the file out to data storage.

static int 
fatfs_fo_fsync(struct CYG_FILE_TAG *fp, int mode)
{
    return ENOERR;
}

// -------------------------------------------------------------------------
// fatfs_fo_close()
// Close a file.

static int
fatfs_fo_close(struct CYG_FILE_TAG *fp)
{    
    fatfs_disk_t *disk = (fatfs_disk_t *)fp->f_mte->data;
    fatfs_node_t *node = (fatfs_node_t *)fp->f_data;
    int err = ENOERR;

    printf( "Close fp=%p", fp);

    if (node != disk->root)
        err = fatfs_write_file_attr(disk, node);
    fatfs_node_unref(disk, node);    

    return err;
}

// -------------------------------------------------------------------------
// fatfs_fo_fstat()
// Get file status.

static int
fatfs_fo_fstat(struct CYG_FILE_TAG *fp, struct stat *buf)
{
    fatfs_node_t *node = (fatfs_node_t *)fp->f_data;
    
    printf( "Fstat fp=%p buf=%p", fp, buf);

    // Fill in the status
    buf->st_mode   = node->mode;
    buf->st_ino    = (ino_t)node->cluster;
    buf->st_dev    = 0;
    buf->st_nlink  = 1;
    buf->st_uid    = 0;
    buf->st_gid    = 0;
    buf->st_size   = node->size;
    buf->st_atime  = node->atime;
    buf->st_mtime  = node->mtime;
    buf->st_ctime  = node->ctime;

    return ENOERR;
}

// -------------------------------------------------------------------------
// fatfs_fo_getinfo()
// Get info.

static int
fatfs_fo_getinfo(struct CYG_FILE_TAG *fp, int key, void *buf, int len)
{
    printf( "Getinfo fp=%p key=%d buf=%p len=%d", fp, key, buf, len);
    return EINVAL;
}

// -------------------------------------------------------------------------
// fatfs_fo_setinfo()
// Set info.

static int
fatfs_fo_setinfo(struct CYG_FILE_TAG *fp, int key, void *buf, int len)
{
    printf( "Setinfo fp=%p key=%d buf=%p len=%d", fp, key, buf, len);
    return EINVAL;
}

//==========================================================================
// Directory operations

// -------------------------------------------------------------------------
// fatfs_fo_dirread()
// Read a single directory entry from a file.

static int 
fatfs_fo_dirread(struct CYG_FILE_TAG *fp, struct CYG_UIO_TAG *uio)
{
    fatfs_disk_t *disk = (fatfs_disk_t *)fp->f_mte->data;
    fatfs_node_t *dir  = (fatfs_node_t *)fp->f_data;
    struct dirent *ent = (struct dirent *)uio->uio_iov[0].iov_base;
    cyg_uint32 pos     = fp->f_offset;
    char *nbuf         = ent->d_name;
    off_t len          = uio->uio_iov[0].iov_len;
    fatfs_node_t node;
    int err;
    
    printf( "Dirread fp=%p uio=%p pos=%d", fp, uio, pos);

    if (len < sizeof(struct dirent))
        return EINVAL;

    err = fatfs_get_dir_entry_node(disk, dir, &pos, &node);

    if (err != ENOERR)
        return (err == EEOF ? ENOERR : err);

    strcpy(nbuf, node.filename);

    dir->atime      = timeGetTime();
    uio->uio_resid -= sizeof(struct dirent);
    fp->f_offset    = (off_t)(pos + 1);
    
    return ENOERR;
}

// -------------------------------------------------------------------------
// fatfs_fo_dirlseek()
// Seek directory to start.

static int 
fatfs_fo_dirlseek(struct CYG_FILE_TAG *fp, off_t *pos, int whence)
{
    printf( "Dirlseek fp=%p whence=%d", fp, whence);

    // Only allow SEEK_SET to zero
    
    if (whence != SEEK_SET || *pos != 0)
        return EINVAL;
    
    *pos = fp->f_offset = 0;
    return ENOERR;
}

// -------------------------------------------------------------------------
// EOF fatfs.c
//以下所有代码都是柯南加的。

int main()
{
	InitialDevice();
	FormatDisk();
	EndDevice();

}