DFS中devfs.c的dfs_device_fs_open函数疑似有遗漏

发布于 2014-12-14 19:53:47 浏览：2093 订阅该版

LZ想通过挂载devfs文件系统到DFS，来实现用文件API访问设备
使用中发现对某个设备调用open函数OK，但open后调用write却返回错误。跟踪发现在devfs.c的dfs_device_fs_open函数中：
```int dfs_device_fs_open(struct dfs_fd *file)
{
    rt_device_t device;

if (file->flags & DFS_O_CREAT)
        return -DFS_STATUS_EINVAL;

/* open root directory */
    if ((file->path[0] == '/') && (file->path[1] == '�') &&
        (file->flags & DFS_O_DIRECTORY))
    {
        struct rt_object *object;
        struct rt_list_node *node;
        struct rt_object_information *information;
        struct device_dirent *root_dirent;
        rt_uint32_t count = 0;
        
        extern struct rt_object_information rt_object_container[];

/* lock scheduler */
        rt_enter_critical();

/* traverse device object */
        information = &rt_object_container[RT_Object_Class_Device];
        for (node = information->object_list.next; node != &(information->object_list); node = node->next)
        {
            count ++;
        }

root_dirent = (struct device_dirent *)rt_malloc(sizeof(struct device_dirent) + 
            count * sizeof(rt_device_t));
        if (root_dirent != RT_NULL)
        {
            root_dirent->devices = (rt_device_t *)(root_dirent + 1);
            root_dirent->read_index = 0;
            root_dirent->device_count = count;
            count = 0;
            /* get all device node */
            for (node = information->object_list.next; node != &(information->object_list); node = node->next)
            {
                object = rt_list_entry(node, struct rt_object, list);
                root_dirent->devices[count] = (rt_device_t)object;
                count ++;
            }
        }
        rt_exit_critical();

/* set data */
        file->data = root_dirent;
        
        return DFS_STATUS_OK;
    }

device = rt_device_find(&file->path[1]);
    if (device == RT_NULL)
        return -DFS_STATUS_ENODEV;

file->data = device;
    
    return DFS_STATUS_OK;
}```

执行完rt_device_find后，并未调用rt_device_open。这导致了设备实际并未打开，故无法写入。大家遇到过这种情况吗？