10 使用的usbhost,插着U盘初次上电的时候，U盘一直挂载失败

发布于 2020-12-03 19:22:21 浏览：1818 订阅该版

```c
static int dfs_uffs_open(struct dfs_fd* file)
{
    int fd;
    int oflag, mode;
    char * file_path;

oflag = file->flags;
    if (oflag & O_DIRECTORY)   /* operations about dir */
    {
        uffs_DIR * dir;

if (oflag & O_CREAT)   /* create a dir*/
        {
            if (uffs_mkdir(file->path) < 0)
                return uffs_result_to_dfs(uffs_get_error());
        }
        /* open dir */
        file_path = rt_malloc(FILE_PATH_MAX);
        if(file_path == RT_NULL)
            return -ENOMEM;

if (file->path[0] == '/' && !(file->path[1] == 0))
            rt_snprintf(file_path, FILE_PATH_MAX, "%s/", file->path);
        else
        {
            file_path[0] = '/';
            file_path[1] = 0;
        }

dir = uffs_opendir(file_path);

if (dir == RT_NULL)
        {
            rt_free(file_path);         
            return uffs_result_to_dfs(uffs_get_error());
        }
        /* save this pointer,will used by  dfs_uffs_getdents*/
        file->data = dir;
        rt_free(file_path);
        return RT_EOK;
    }
    /* regular file operations */
    /* int uffs_open(const char *name, int oflag, ...); what is this?
     * uffs_open can open dir!!  **/
    mode = 0;
    if (oflag & O_RDONLY) mode |= UO_RDONLY;
    if (oflag & O_WRONLY) mode |= UO_WRONLY;
    if (oflag & O_RDWR)   mode |= UO_RDWR;
    /* Opens the file, if it is existing. If not, a new file is created. */
    if (oflag & O_CREAT) mode |= UO_CREATE;
    /* Creates a new file. If the file is existing, it is truncated and overwritten. */
    if (oflag & O_TRUNC) mode |= UO_TRUNC;
    /* Creates a new file. The function fails if the file is already existing. */
    if (oflag & O_EXCL) mode |= UO_EXCL;

fd = uffs_open(file->path, mode);
    if (fd < 0)
    {
        return uffs_result_to_dfs(uffs_get_error());
    }

/* save this pointer, it will be used when calling read(), write(),
     * flush(), seek(), and will be free when calling close()*/

file->data = (void *)fd;
    file->pos  = uffs_seek(fd, 0, USEEK_CUR);
    file->size = uffs_seek(fd, 0, USEEK_END);
    uffs_seek(fd, file->pos, USEEK_SET);

if (oflag & O_APPEND)
    {
        file->pos = uffs_seek(fd, 0, USEEK_END);
    }
    return 0;
}
```