# bend-open-under: package entry for BendHub.
# Source: bendlang/bend PR #1106 (reviewed by VictorTaelin; closed as
# WONTFIX (CAPACITY) and rerouted here: "a clean and careful walk ... works
# just as well as a foreign effect in a hub package, with the same C code").
#
# Open a path read-only, below a directory root, never through a symbolic
# link: one openat2 (RESOLVE_BENEATH, Linux 5.6+), else an openat walk, one
# component at a time, each with O_NOFOLLOW, every step re-checked so a swap
# between check and open cannot slip through. A link, a missing name, a
# directory, an empty, "." or ".." component and a path that climbs out of
# root all fail; the root is taken as given.
import Base

# path, read-only, below root and never through a symbolic link: a link,
# a missing name, a directory, an empty, "." or ".." component and a
# climb out of root all fail. root is taken as given.
def File.open_under(root: String, path: String) ->
  IO(Result<&1, &1, U32 & String, File>):
  import "./file_open_under.c"
  import "./file_open_under.js"