Function dfs_file_read

components/dfs/dfs_v1/src/dfs_file.c:425–445

* this function will read specified length data from a file descriptor to a * buffer. * * @param fd the file descriptor. * @param buf the buffer to save the read data. * @param len the length of data buffer to be read. * * @return the actual read data bytes or 0 on end of file or failed. */

 * @return the actual read data bytes or 0 on end of file or failed.
 */
ssize_t dfs_file_read(struct dfs_file *fd, void *buf, size_t len)
{
    int result = 0;

    if (fd == NULL)
    {
        return -EINVAL;
    }

    if (fd->vnode->fops->read == NULL)
    {
        return -ENOSYS;
    }

    if ((result = fd->vnode->fops->read(fd, buf, len)) < 0)
    {
        fd->flags |= DFS_F_EOF;
    }

    return result;
}

/**
 * this function will fetch directory entries from a directory descriptor.