Mount and unmount FUSE filesystems via the fusermount3 helper.

The Linux FUSE kernel ABI requires a userspace helper for unprivileged mounts: a setuid fusermount3 binary opens /dev/fuse, performs the mount(2) syscall on behalf of the caller, and returns the resulting fd over a SCM_RIGHTS Unix socket. This module wraps that protocol.

Mount

mount/2 invokes fusermount3 via Wick.Native.fusermount3_mount/2 and returns the handle wrapping the FUSE fd, ready to use with Wick.Native.select_read/1, read_frame/1 and write_frame/2.

Unmount

unmount/1 invokes fusermount3 -u <mount_point> via an Erlang Port so that the BEAM's child-process management (through erl_child_setup) reaps the helper without colliding with SIGCHLD = SIG_IGN. The fuser crate's direct fusermount3 invocation is broken under the BEAM for exactly this reason — see the parent epic (#107) for context.

Example

{:ok, handle} =
  Wick.Fusermount.mount(
    "/tmp/my-mount",
    ["fsname=wick", "subtype=wick", "default_permissions"]
  )

# ... use the handle to drive the FUSE protocol ...

:ok = Wick.Fusermount.unmount("/tmp/my-mount")

Options

mount/2 accepts options as a list of strings; they are joined with , and passed as a single argument to fusermount3 -o. Each option is either a flag ("allow_other") or a key=value pair ("max_read=131072"). The list may be empty, in which case fusermount3 is invoked with -o "", accepting only the kernel defaults. No validation is performed here — invalid options surface as {:error, :fusermount_no_fd} from the helper.