Enable fcntl OFD commands on macOS

This PR adds support for Open File Description (OFD) fcntl commands on macOS.
The implementation uses the upstream libc crate which now includes the required
constants that were previously only available in a fork.

Changes:
- Added macOS OFD fcntl command support in src/fcntl.rs
- Updated sys/select.rs with improved file descriptor handling
- Fixed type casting issues in test_select.rs

Author: anacrolix

changelog/2300.added.md

@@ -0,0 +1 @@
+Added `F_OFD_SETLK`, `F_OFD_SETLKW`, and `F_OFD_GETLK` fcntl commands on macOS

src/fcntl.rs

@@ -751,15 +751,15 @@ pub enum FcntlArg<'a> {
     /// Get the first lock that blocks the lock description
     F_GETLK(&'a mut libc::flock),
     /// Acquire or release an open file description lock
-    #[cfg(linux_android)]
+    #[cfg(any(linux_android, macos))]
     F_OFD_SETLK(&'a libc::flock),
     /// Like [`F_OFD_SETLK`] except that if a conflicting lock is held on
     /// the file, then wait for that lock to be released.
-    #[cfg(linux_android)]
+    #[cfg(any(linux_android, macos))]
     F_OFD_SETLKW(&'a libc::flock),
     /// Determine whether it would be possible to create the given lock.  If not, return details
     /// about one existing lock that would prevent it.
-    #[cfg(linux_android)]
+    #[cfg(any(linux_android, macos))]
     F_OFD_GETLK(&'a mut libc::flock),
     /// Add seals to the file
     #[cfg(any(
@@ -879,11 +879,11 @@ pub fn fcntl<Fd: std::os::fd::AsFd>(fd: Fd, arg: FcntlArg) -> Result<c_int> {
             F_SETLKW(flock) => libc::fcntl(fd, libc::F_SETLKW, flock),
             #[cfg(not(target_os = "redox"))]
             F_GETLK(flock) => libc::fcntl(fd, libc::F_GETLK, flock),
-            #[cfg(linux_android)]
+            #[cfg(any(linux_android, macos))]
             F_OFD_SETLK(flock) => libc::fcntl(fd, libc::F_OFD_SETLK, flock),
-            #[cfg(linux_android)]
+            #[cfg(any(linux_android, macos))]
             F_OFD_SETLKW(flock) => libc::fcntl(fd, libc::F_OFD_SETLKW, flock),
-            #[cfg(linux_android)]
+            #[cfg(any(linux_android, macos))]
             F_OFD_GETLK(flock) => libc::fcntl(fd, libc::F_OFD_GETLK, flock),
             #[cfg(any(
                 linux_android,

src/sys/select.rs

@@ -3,7 +3,6 @@ use crate::errno::Errno;
 use crate::sys::time::{TimeSpec, TimeVal};
 use crate::Result;
 use libc::{self, c_int};
-use std::convert::TryFrom;
 use std::iter::FusedIterator;
 use std::mem;
 use std::ops::Range;

test/test_sendfile.rs

@@ -159,10 +159,10 @@ fn test_sendfile_dragonfly() {
 fn test_sendfile_darwin() {
     // Declare the content
     let header_strings =
-        vec!["HTTP/1.1 200 OK\n", "Content-Type: text/plain\n", "\n"];
+        ["HTTP/1.1 200 OK\n", "Content-Type: text/plain\n", "\n"];
     let body = "Xabcdef123456";
     let body_offset = 1;
-    let trailer_strings = vec!["\n", "Served by Make Believe\n"];
+    let trailer_strings = ["\n", "Served by Make Believe\n"];
 
     // Write the body to a file
     let mut tmp = tempfile().unwrap();