From e99ad986d5ba607df14f0796f02ab2734106338a Mon Sep 17 00:00:00 2001
From: Brian Smith <brian@briansmith.org>
Date: Mon, 17 Jun 2024 10:58:10 -0700
Subject: [PATCH] MSRV 1.63: use_file: Clarify I/O safety using `BorrowedFd`.

---
 .clippy.toml                |  2 +-
 .github/workflows/tests.yml |  2 +-
 Cargo.toml                  |  2 +-
 README.md                   |  2 +-
 src/use_file.rs             | 16 +++++++---------
 5 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/.clippy.toml b/.clippy.toml
index 13f202e9..550d4759 100644
--- a/.clippy.toml
+++ b/.clippy.toml
@@ -1 +1 @@
-msrv = "1.60"
+msrv = "1.63"
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 922e8fd4..149c4288 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -22,7 +22,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-22.04, windows-2022]
-        toolchain: [nightly, beta, stable, "1.60"]
+        toolchain: [nightly, beta, stable, "1.63"]
         # Only Test macOS on stable to reduce macOS CI jobs
         include:
           # x86_64-apple-darwin.
diff --git a/Cargo.toml b/Cargo.toml
index 47c7fd28..f2b7445b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,7 +2,7 @@
 name = "getrandom"
 version = "0.2.15" # Also update html_root_url in lib.rs when bumping this
 edition = "2021"
-rust-version = "1.60" # Sync .clippy.toml, tests.yml, and README.md.
+rust-version = "1.63" # Sync .clippy.toml, tests.yml, and README.md.
 authors = ["The Rand Project Developers"]
 license = "MIT OR Apache-2.0"
 description = "A small cross-platform library for retrieving random data from system source"
diff --git a/README.md b/README.md
index ef8a6ce2..bbab4f28 100644
--- a/README.md
+++ b/README.md
@@ -52,7 +52,7 @@ crate features, WASM support and Custom RNGs see the
 
 ## Minimum Supported Rust Version
 
-This crate requires Rust 1.60.0 or later.
+This crate requires Rust 1.63.0 or later.
 
 ## Platform Support
 
diff --git a/src/use_file.rs b/src/use_file.rs
index ef215182..653775e9 100644
--- a/src/use_file.rs
+++ b/src/use_file.rs
@@ -11,7 +11,7 @@ use core::{
 };
 use std::{
     fs, io,
-    os::fd::{IntoRawFd as _, RawFd},
+    os::fd::{AsRawFd as _, BorrowedFd, IntoRawFd as _, RawFd},
 };
 
 /// For all platforms, we use `/dev/urandom` rather than `/dev/random`.
@@ -28,28 +28,28 @@ const FILE_PATH: &str = "/dev/urandom";
 pub fn getrandom_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
     let fd = get_rng_fd()?;
     sys_fill_exact(dest, |buf| unsafe {
-        libc::read(fd, buf.as_mut_ptr().cast::<c_void>(), buf.len())
+        libc::read(fd.as_raw_fd(), buf.as_mut_ptr().cast::<c_void>(), buf.len())
     })
 }
 
 // Returns the file descriptor for the device file used to retrieve random
 // bytes. The file will be opened exactly once. All subsequent calls will
 // return the same file descriptor. This file descriptor is never closed.
-fn get_rng_fd() -> Result<RawFd, Error> {
+fn get_rng_fd() -> Result<BorrowedFd<'static>, Error> {
     // std::os::fd::{BorrowedFd, OwnedFd} guarantee that -1 is not a valid file descriptor.
     const FD_UNINIT: RawFd = -1;
 
     static FD: AtomicI32 = AtomicI32::new(FD_UNINIT);
 
-    fn get_fd() -> Option<RawFd> {
+    fn get_fd() -> Option<BorrowedFd<'static>> {
         match FD.load(Relaxed) {
             FD_UNINIT => None,
-            val => Some(val),
+            val => Some(unsafe { BorrowedFd::borrow_raw(val) }),
         }
     }
 
     #[cold]
-    fn get_fd_locked() -> Result<RawFd, Error> {
+    fn get_fd_locked() -> Result<BorrowedFd<'static>, Error> {
         // SAFETY: We use the mutex only in this method, and we always unlock it
         // before returning, making sure we don't violate the pthread_mutex_t API.
         static MUTEX: Mutex = Mutex::new();
@@ -71,7 +71,7 @@ fn get_rng_fd() -> Result<RawFd, Error> {
         debug_assert!(fd != FD_UNINIT);
         FD.store(fd, Relaxed);
 
-        Ok(fd)
+        Ok(unsafe { BorrowedFd::borrow_raw(fd) })
     }
 
     // Use double-checked locking to avoid acquiring the lock if possible.
@@ -112,8 +112,6 @@ fn get_rng_fd() -> Result<RawFd, Error> {
 // libsodium uses `libc::poll` similarly to this.
 #[cfg(any(target_os = "android", target_os = "linux"))]
 fn wait_until_rng_ready() -> Result<(), Error> {
-    use std::os::unix::io::AsRawFd as _;
-
     let file = fs::File::open("/dev/random").map_err(map_io_error)?;
     let mut pfd = libc::pollfd {
         fd: file.as_raw_fd(),