4 files changed, 52 insertions, 0 deletions
diff --git a/library/std/src/os/wasi/io/fd.rs b/library/std/src/os/wasi/io/fd.rs
new file mode 100644
index 000000000..930aca887
--- /dev/null
+++ b/library/std/src/os/wasi/io/fd.rs
@@ -0,0 +1,9 @@
+//! Owned and borrowed file descriptors.
+
+#![unstable(feature = "wasi_ext", issue = "71213")]
+
+// Tests for this module
+#[cfg(test)]
+mod tests;
+
+pub use crate::os::fd::owned::*;
diff --git a/library/std/src/os/wasi/io/fd/tests.rs b/library/std/src/os/wasi/io/fd/tests.rs
new file mode 100644
index 000000000..418274752
--- /dev/null
+++ b/library/std/src/os/wasi/io/fd/tests.rs
@@ -0,0 +1,11 @@
+use crate::mem::size_of;
+use crate::os::wasi::io::RawFd;
+
+#[test]
+fn test_raw_fd_layout() {
+    // `OwnedFd` and `BorrowedFd` use `rustc_layout_scalar_valid_range_start`
+    // and `rustc_layout_scalar_valid_range_end`, with values that depend on
+    // the bit width of `RawFd`. If this ever changes, those values will need
+    // to be updated.
+    assert_eq!(size_of::<RawFd>(), 4);
+}
diff --git a/library/std/src/os/wasi/io/mod.rs b/library/std/src/os/wasi/io/mod.rs
new file mode 100644
index 000000000..6c884e2ea
--- /dev/null
+++ b/library/std/src/os/wasi/io/mod.rs
@@ -0,0 +1,12 @@
+//! WASI-specific extensions to general I/O primitives.
+
+#![deny(unsafe_op_in_unsafe_fn)]
+#![unstable(feature = "wasi_ext", issue = "71213")]
+
+mod fd;
+mod raw;
+
+#[unstable(feature = "wasi_ext", issue = "71213")]
+pub use fd::*;
+#[unstable(feature = "wasi_ext", issue = "71213")]
+pub use raw::*;
diff --git a/library/std/src/os/wasi/io/raw.rs b/library/std/src/os/wasi/io/raw.rs
new file mode 100644
index 000000000..da3b36ada
--- /dev/null
+++ b/library/std/src/os/wasi/io/raw.rs
@@ -0,0 +1,20 @@
+//! WASI-specific extensions to general I/O primitives.
+
+#![unstable(feature = "wasi_ext", issue = "71213")]
+
+// NOTE: despite the fact that this module is unstable,
+// stable Rust had the capability to access the stable
+// re-exported items from os::fd::raw through this
+// unstable module.
+// In PR #95956 the stability checker was changed to check
+// all path segments of an item rather than just the last,
+// which caused the aforementioned stable usage to regress
+// (see issue #99502).
+// As a result, the items in os::fd::raw were given the
+// rustc_allowed_through_unstable_modules attribute.
+// No regression tests were added to ensure this property,
+// as CI is not configured to test wasm32-wasi.
+// If this module is stabilized,
+// you may want to remove those attributes
+// (assuming no other unstable modules need them).
+pub use crate::os::fd::raw::*;