From fbf64704409fa4e54faaa37afa5eaac34c127c53 Mon Sep 17 00:00:00 2001
From: Alan Somers <asomers@gmail.com>
Date: Sun, 4 Dec 2022 08:35:35 -0700
Subject: [PATCH] Use AsFd in copy_file_range

---
 CHANGELOG.md       | 11 ++++++++++-
 src/fcntl.rs       | 18 +++++++++++-------
 test/test_fcntl.rs |  6 +++---
 3 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 89e47772ba..0c4c63e2b1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,13 +10,22 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 - Added `nix::ucontext` module on `aarch64-unknown-linux-gnu`.
   (#[1662](https://github.com/nix-rust/nix/pull/1662))
 - Exposed `copy_file_range` on FreeBSD
-  (#[???](https://github.com/nix-rust/nix/pull/???))
+  (#[1906](https://github.com/nix-rust/nix/pull/1906))
 
 ### Changed
 
 - The MSRV is now 1.63
   ([#1862](https://github.com/nix-rust/nix/pull/1862))
 
+- Implemented I/O safety.  Many public functions argument and return types have
+  changed:
+  | Original Type | New Type              |
+  | ------------- | --------------------- |
+  | AsRawFd       | AsFd                  |
+  | RawFd         | BorrowedFd or OwnedFd |
+
+  (#[1906](https://github.com/nix-rust/nix/pull/1906))
+
 ### Fixed
 ### Removed
 
diff --git a/src/fcntl.rs b/src/fcntl.rs
index c4c1e92f82..0c7066a8bb 100644
--- a/src/fcntl.rs
+++ b/src/fcntl.rs
@@ -5,11 +5,15 @@ use std::ffi::OsString;
 use std::os::raw;
 use std::os::unix::ffi::OsStringExt;
 use std::os::unix::io::RawFd;
+// For splice and copy_file_range
+#[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
+use std::{
+    os::unix::io::{AsRawFd, AsFd},
+    ptr
+};
 
 #[cfg(feature = "fs")]
 use crate::{sys::stat::Mode, NixPath, Result};
-#[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
-use std::ptr; // For splice and copy_file_range
 
 #[cfg(any(
     target_os = "linux",
@@ -593,10 +597,10 @@ type type_of_off = libc::off_t;
 /// On successful completion the number of bytes actually copied will be
 /// returned.
 #[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
-pub fn copy_file_range(
-    fd_in: RawFd,
+pub fn copy_file_range<Fd1: AsFd, Fd2: AsFd>(
+    fd_in: Fd1,
     off_in: Option<&mut type_of_off>,
-    fd_out: RawFd,
+    fd_out: Fd2,
     off_out: Option<&mut type_of_off>,
     len: usize,
 ) -> Result<usize> {
@@ -609,9 +613,9 @@ pub fn copy_file_range(
 
     let ret = unsafe {
         libc::copy_file_range(
-            fd_in,
+            fd_in.as_fd().as_raw_fd(),
             off_in,
-            fd_out,
+            fd_out.as_fd().as_raw_fd(),
             off_out,
             len,
             0,
diff --git a/test/test_fcntl.rs b/test/test_fcntl.rs
index dca6b79bfb..6df9190a8a 100644
--- a/test/test_fcntl.rs
+++ b/test/test_fcntl.rs
@@ -243,7 +243,7 @@ fn test_readlink() {
 // QEMU does not support copy_file_range. Skip under qemu
 #[cfg_attr(qemu, ignore)]
 fn test_copy_file_range() {
-    use std::os::unix::io::AsRawFd;
+    use std::os::unix::io::AsFd;
     use nix::fcntl::copy_file_range;
 
     const CONTENTS: &[u8] = b"foobarbaz";
@@ -256,9 +256,9 @@ fn test_copy_file_range() {
 
     let mut from_offset: i64 = 3;
     copy_file_range(
-        tmp1.as_raw_fd(),
+        tmp1.as_fd(),
         Some(&mut from_offset),
-        tmp2.as_raw_fd(),
+        tmp2.as_fd(),
         None,
         3,
     )