具有libfuse和文件所有权的自定义fs

Question

当用户创建文件时，将调用create回调：

int (*create) (const char *, mode_t, struct fuse_file_info *);

有关详细信息，请参阅链接https://github.com/libfuse/libfuse/blob/74596e2929c9b9b065f90d04ab7a2232652c64c4/include/fuse.h#L609

但并没有关于用户想要创建文件的信息，这意味着文件将始终由融合进程运行的所有者用户创建。

例如，我以root身份启动了fuse进程，但从我的用户创建了文件：

$ echo $USERNAME
myuser
$ echo 'f' > f
$ ll
$ ll
total 4,0K
-rw-r--r-- 1 root root

Answer 1

您可以使用全局fuse上下文获取调用用户的uid和gid：

struct fuse_context *cxt = fuse_get_context();
if (cxt)
uid = cxt->uid;
gid = cxt->gid;

来自保险丝h:

/** Extra context that may be needed by some filesystems
*
* The uid, gid and pid fields are not filled in case of a writepage
* operation.
*/
struct fuse_context {
/** Pointer to the fuse object */
struct fuse *fuse;
/** User ID of the calling process */
uid_t uid;
/** Group ID of the calling process */
gid_t gid;
/** Process ID of the calling thread */
pid_t pid;
/** Private filesystem data */
void *private_data;
/** Umask of the calling process */
mode_t umask;
};