Remove emulation of FD_CLOEXEC/O_NONBLOCK

Rather than using the native implementation of these constants
on supported platforms, the native implementation was instead
emulated. This was also hidden from the user even though this
could result in data races and the functionality being broken.

Native functionality is, however, not support on macos/ios.
Rather than enable this emulation solely for this platform, it
should be removed as this is a dangerous abstraction.

1 files changed, 21 insertions, 98 deletions

diff --git a/src/sys/socket/mod.rs b/src/sys/socket/mod.rs
index fcb79af9..b46fa8b0 100644
--- a/src/sys/socket/mod.rs
+++ b/src/sys/socket/mod.rs
@@ -3,7 +3,6 @@
 //! [Further reading](http://man7.org/linux/man-pages/man7/socket.7.html)
 use {Error, Result};
 use errno::Errno;
-use features;
 use libc::{self, c_void, c_int, socklen_t, size_t};
 use std::{fmt, mem, ptr, slice};
 use std::os::unix::io::RawFd;
@@ -692,42 +691,20 @@ pub fn recvmsg<'a, T>(fd: RawFd, iov: &[IoVec<&mut [u8]>], cmsg_buffer: Option<&
 ///
 /// [Further reading](http://pubs.opengroup.org/onlinepubs/9699919799/functions/socket.html)
 pub fn socket<T: Into<Option<SockProtocol>>>(domain: AddressFamily, ty: SockType, flags: SockFlag, protocol: T) -> Result<RawFd> {
-    let mut ty = ty as c_int;
     let protocol = match protocol.into() {
         None => 0,
         Some(p) => p as c_int,
     };
-    let feat_atomic = features::socket_atomic_cloexec();
-
-    if feat_atomic {
-        ty |= flags.bits();
-    }
-
-    // TODO: Check the kernel version
-    let res = try!(Errno::result(unsafe { libc::socket(domain as c_int, ty, protocol) }));
-
-    #[cfg(any(target_os = "android",
-              target_os = "dragonfly",
-              target_os = "freebsd",
-              target_os = "linux",
-              target_os = "netbsd",
-              target_os = "openbsd"))]
-    {
-        use fcntl::{fcntl, FdFlag, OFlag};
-        use fcntl::FcntlArg::{F_SETFD, F_SETFL};
 
-        if !feat_atomic {
-            if flags.contains(SockFlag::SOCK_CLOEXEC) {
-                try!(fcntl(res, F_SETFD(FdFlag::FD_CLOEXEC)));
-            }
+    // SockFlags are usually embedded into `ty`, but we don't do that in `nix` because it's a
+    // little easier to understand by separating it out. So we have to merge these bitfields
+    // here.
+    let mut ty = ty as c_int;
+    ty |= flags.bits();
 
-            if flags.contains(SockFlag::SOCK_NONBLOCK) {
-                try!(fcntl(res, F_SETFL(OFlag::O_NONBLOCK)));
-            }
-        }
-    }
+    let res = unsafe { libc::socket(domain as c_int, ty, protocol) };
 
-    Ok(res)
+    Errno::result(res)
 }
 
 /// Create a pair of connected sockets
@@ -735,44 +712,22 @@ pub fn socket<T: Into<Option<SockProtocol>>>(domain: AddressFamily, ty: SockType
 /// [Further reading](http://pubs.opengroup.org/onlinepubs/9699919799/functions/socketpair.html)
 pub fn socketpair<T: Into<Option<SockProtocol>>>(domain: AddressFamily, ty: SockType, protocol: T,
                   flags: SockFlag) -> Result<(RawFd, RawFd)> {
-    let mut ty = ty as c_int;
     let protocol = match protocol.into() {
         None => 0,
         Some(p) => p as c_int,
     };
-    let feat_atomic = features::socket_atomic_cloexec();
 
-    if feat_atomic {
-        ty |= flags.bits();
-    }
+    // SockFlags are usually embedded into `ty`, but we don't do that in `nix` because it's a
+    // little easier to understand by separating it out. So we have to merge these bitfields
+    // here.
+    let mut ty = ty as c_int;
+    ty |= flags.bits();
+
     let mut fds = [-1, -1];
-    let res = unsafe {
-        libc::socketpair(domain as c_int, ty, protocol, fds.as_mut_ptr())
-    };
-    try!(Errno::result(res));
-
-    #[cfg(any(target_os = "android",
-              target_os = "dragonfly",
-              target_os = "freebsd",
-              target_os = "linux",
-              target_os = "netbsd",
-              target_os = "openbsd"))]
-    {
-        use fcntl::{fcntl, FdFlag, OFlag};
-        use fcntl::FcntlArg::{F_SETFD, F_SETFL};
 
-        if !feat_atomic {
-            if flags.contains(SockFlag::SOCK_CLOEXEC) {
-                try!(fcntl(fds[0], F_SETFD(FdFlag::FD_CLOEXEC)));
-                try!(fcntl(fds[1], F_SETFD(FdFlag::FD_CLOEXEC)));
-            }
+    let res = unsafe { libc::socketpair(domain as c_int, ty, protocol, fds.as_mut_ptr()) };
+    Errno::result(res)?;
 
-            if flags.contains(SockFlag::SOCK_NONBLOCK) {
-                try!(fcntl(fds[0], F_SETFL(OFlag::O_NONBLOCK)));
-                try!(fcntl(fds[1], F_SETFL(OFlag::O_NONBLOCK)));
-            }
-        }
-    }
     Ok((fds[0], fds[1]))
 }
 
@@ -809,46 +764,14 @@ pub fn accept(sockfd: RawFd) -> Result<RawFd> {
 /// Accept a connection on a socket
 ///
 /// [Further reading](http://man7.org/linux/man-pages/man2/accept.2.html)
+#[cfg(any(target_os = "android",
+          target_os = "freebsd",
+          target_os = "linux",
+          target_os = "openbsd"))]
 pub fn accept4(sockfd: RawFd, flags: SockFlag) -> Result<RawFd> {
-    accept4_polyfill(sockfd, flags)
-}
-
-#[inline]
-fn accept4_polyfill(sockfd: RawFd, flags: SockFlag) -> Result<RawFd> {
-    let res = try!(Errno::result(unsafe { libc::accept(sockfd, ptr::null_mut(), ptr::null_mut()) }));
-
-    #[cfg(any(target_os = "android",
-              target_os = "dragonfly",
-              target_os = "freebsd",
-              target_os = "linux",
-              target_os = "netbsd",
-              target_os = "openbsd"))]
-    {
-        use fcntl::{fcntl, FdFlag, OFlag};
-        use fcntl::FcntlArg::{F_SETFD, F_SETFL};
-
-        if flags.contains(SockFlag::SOCK_CLOEXEC) {
-            try!(fcntl(res, F_SETFD(FdFlag::FD_CLOEXEC)));
-        }
-
-        if flags.contains(SockFlag::SOCK_NONBLOCK) {
-            try!(fcntl(res, F_SETFL(OFlag::O_NONBLOCK)));
-        }
-    }
-
-    // Disable unused variable warning on some platforms
-    #[cfg(not(any(target_os = "android",
-                  target_os = "dragonfly",
-                  target_os = "freebsd",
-                  target_os = "linux",
-                  target_os = "netbsd",
-                  target_os = "openbsd")))]
-    {
-        let _ = flags;
-    }
+    let res = unsafe { libc::accept4(sockfd, ptr::null_mut(), ptr::null_mut(), flags.bits()) };
 
-
-    Ok(res)
+    Errno::result(res)
 }
 
 /// Initiate a connection on a socket