Add I/O safety to sockopt and some socket functions

* socket
* socketpair
* listen
* setsockopt
* getsockopt

Author: asomers

src/sys/socket/addr.rs

@@ -845,9 +845,10 @@ pub trait SockaddrLike: private::SockaddrLikePriv {
     /// One common use is to match on the family of a union type, like this:
     /// ```
     /// # use nix::sys::socket::*;
+    /// # use std::os::unix::io::AsRawFd;
     /// let fd = socket(AddressFamily::Inet, SockType::Stream,
     ///     SockFlag::empty(), None).unwrap();
-    /// let ss: SockaddrStorage = getsockname(fd).unwrap();
+    /// let ss: SockaddrStorage = getsockname(fd.as_raw_fd()).unwrap();
     /// match ss.family().unwrap() {
     ///     AddressFamily::Inet => println!("{}", ss.as_sockaddr_in().unwrap()),
     ///     AddressFamily::Inet6 => println!("{}", ss.as_sockaddr_in6().unwrap()),
@@ -1208,11 +1209,12 @@ impl std::str::FromStr for SockaddrIn6 {
 /// ```
 /// # use nix::sys::socket::*;
 /// # use std::str::FromStr;
+/// # use std::os::unix::io::AsRawFd;
 /// let localhost = SockaddrIn::from_str("127.0.0.1:8081").unwrap();
 /// let fd = socket(AddressFamily::Inet, SockType::Stream, SockFlag::empty(),
 ///     None).unwrap();
-/// bind(fd, &localhost).expect("bind");
-/// let ss: SockaddrStorage = getsockname(fd).expect("getsockname");
+/// bind(fd.as_raw_fd(), &localhost).expect("bind");
+/// let ss: SockaddrStorage = getsockname(fd.as_raw_fd()).expect("getsockname");
 /// assert_eq!(&localhost, ss.as_sockaddr_in().unwrap());
 /// ```
 #[derive(Clone, Copy, Eq)]

src/sys/socket/mod.rs

@@ -15,7 +15,7 @@ use libc::{
 use std::io::{IoSlice, IoSliceMut};
 #[cfg(feature = "net")]
 use std::net;
-use std::os::unix::io::RawFd;
+use std::os::unix::io::{AsFd, AsRawFd, FromRawFd, RawFd, OwnedFd};
 use std::{mem, ptr, slice};
 
 #[deny(missing_docs)]
@@ -669,6 +669,7 @@ pub enum ControlMessageOwned {
     /// # use std::io::{IoSlice, IoSliceMut};
     /// # use std::time::*;
     /// # use std::str::FromStr;
+    /// # use std::os::unix::io::AsRawFd;
     /// # fn main() {
     /// // Set up
     /// let message = "Ohayō!".as_bytes();
@@ -677,22 +678,22 @@ pub enum ControlMessageOwned {
     ///     SockType::Datagram,
     ///     SockFlag::empty(),
     ///     None).unwrap();
-    /// setsockopt(in_socket, sockopt::ReceiveTimestamp, &true).unwrap();
+    /// setsockopt(&in_socket, sockopt::ReceiveTimestamp, &true).unwrap();
     /// let localhost = SockaddrIn::from_str("127.0.0.1:0").unwrap();
-    /// bind(in_socket, &localhost).unwrap();
-    /// let address: SockaddrIn = getsockname(in_socket).unwrap();
+    /// bind(in_socket.as_raw_fd(), &localhost).unwrap();
+    /// let address: SockaddrIn = getsockname(in_socket.as_raw_fd()).unwrap();
     /// // Get initial time
     /// let time0 = SystemTime::now();
     /// // Send the message
     /// let iov = [IoSlice::new(message)];
     /// let flags = MsgFlags::empty();
-    /// let l = sendmsg(in_socket, &iov, &[], flags, Some(&address)).unwrap();
+    /// let l = sendmsg(in_socket.as_raw_fd(), &iov, &[], flags, Some(&address)).unwrap();
     /// assert_eq!(message.len(), l);
     /// // Receive the message
     /// let mut buffer = vec![0u8; message.len()];
     /// let mut cmsgspace = cmsg_space!(TimeVal);
     /// let mut iov = [IoSliceMut::new(&mut buffer)];
-    /// let r = recvmsg::<SockaddrIn>(in_socket, &mut iov, Some(&mut cmsgspace), flags)
+    /// let r = recvmsg::<SockaddrIn>(in_socket.as_raw_fd(), &mut iov, Some(&mut cmsgspace), flags)
     ///     .unwrap();
     /// let rtime = match r.cmsgs().next() {
     ///     Some(ControlMessageOwned::ScmTimestamp(rtime)) => rtime,
@@ -708,7 +709,6 @@ pub enum ControlMessageOwned {
     /// assert!(time0.duration_since(UNIX_EPOCH).unwrap() <= rduration);
     /// assert!(rduration <= time1.duration_since(UNIX_EPOCH).unwrap());
     /// // Close socket
-    /// nix::unistd::close(in_socket).unwrap();
     /// # }
     /// ```
     ScmTimestamp(TimeVal),
@@ -1427,6 +1427,7 @@ impl<'a> ControlMessage<'a> {
 /// # use nix::sys::socket::*;
 /// # use nix::unistd::pipe;
 /// # use std::io::IoSlice;
+/// # use std::os::unix::io::AsRawFd;
 /// let (fd1, fd2) = socketpair(AddressFamily::Unix, SockType::Stream, None,
 ///     SockFlag::empty())
 ///     .unwrap();
@@ -1435,14 +1436,15 @@ impl<'a> ControlMessage<'a> {
 /// let iov = [IoSlice::new(b"hello")];
 /// let fds = [r];
 /// let cmsg = ControlMessage::ScmRights(&fds);
-/// sendmsg::<()>(fd1, &iov, &[cmsg], MsgFlags::empty(), None).unwrap();
+/// sendmsg::<()>(fd1.as_raw_fd(), &iov, &[cmsg], MsgFlags::empty(), None).unwrap();
 /// ```
 /// When directing to a specific address, the generic type will be inferred.
 /// ```
 /// # use nix::sys::socket::*;
 /// # use nix::unistd::pipe;
 /// # use std::io::IoSlice;
 /// # use std::str::FromStr;
+/// # use std::os::unix::io::AsRawFd;
 /// let localhost = SockaddrIn::from_str("1.2.3.4:8080").unwrap();
 /// let fd = socket(AddressFamily::Inet, SockType::Datagram, SockFlag::empty(),
 ///     None).unwrap();
@@ -1451,7 +1453,7 @@ impl<'a> ControlMessage<'a> {
 /// let iov = [IoSlice::new(b"hello")];
 /// let fds = [r];
 /// let cmsg = ControlMessage::ScmRights(&fds);
-/// sendmsg(fd, &iov, &[cmsg], MsgFlags::empty(), Some(&localhost)).unwrap();
+/// sendmsg(fd.as_raw_fd(), &iov, &[cmsg], MsgFlags::empty(), Some(&localhost)).unwrap();
 /// ```
 pub fn sendmsg<S>(fd: RawFd, iov: &[IoSlice<'_>], cmsgs: &[ControlMessage],
                flags: MsgFlags, addr: Option<&S>) -> Result<usize>
@@ -1799,6 +1801,7 @@ mod test {
     use crate::sys::socket::{AddressFamily, ControlMessageOwned};
     use crate::*;
     use std::str::FromStr;
+    use std::os::unix::io::AsRawFd;
 
     #[cfg_attr(qemu, ignore)]
     #[test]
@@ -1825,9 +1828,9 @@ mod test {
             None,
         )?;
 
-        crate::sys::socket::bind(rsock, &sock_addr)?;
+        crate::sys::socket::bind(rsock.as_raw_fd(), &sock_addr)?;
 
-        setsockopt(rsock, Timestamping, &TimestampingFlag::all())?;
+        setsockopt(&rsock, Timestamping, &TimestampingFlag::all())?;
 
         let sbuf = (0..400).map(|i| i as u8).collect::<Vec<_>>();
 
@@ -1849,13 +1852,13 @@ mod test {
         let iov1 = [IoSlice::new(&sbuf)];
 
         let cmsg = cmsg_space!(crate::sys::socket::Timestamps);
-        sendmsg(ssock, &iov1, &[], flags, Some(&sock_addr)).unwrap();
+        sendmsg(ssock.as_raw_fd(), &iov1, &[], flags, Some(&sock_addr)).unwrap();
 
         let mut data = super::MultiHeaders::<()>::preallocate(recv_iovs.len(), Some(cmsg));
 
         let t = sys::time::TimeSpec::from_duration(std::time::Duration::from_secs(10));
 
-        let recv = super::recvmmsg(rsock, &mut data, recv_iovs.iter(), flags, Some(t))?;
+        let recv = super::recvmmsg(rsock.as_raw_fd(), &mut data, recv_iovs.iter(), flags, Some(t))?;
 
         for rmsg in recv {
             #[cfg(not(any(qemu, target_arch = "aarch64")))]
@@ -2062,7 +2065,7 @@ pub fn socket<T: Into<Option<SockProtocol>>>(
     ty: SockType,
     flags: SockFlag,
     protocol: T,
-) -> Result<RawFd> {
+) -> Result<OwnedFd> {
     let protocol = match protocol.into() {
         None => 0,
         Some(p) => p as c_int,
@@ -2076,7 +2079,13 @@ pub fn socket<T: Into<Option<SockProtocol>>>(
 
     let res = unsafe { libc::socket(domain as c_int, ty, protocol) };
 
-    Errno::result(res)
+    match res {
+        -1 => Err(Errno::last()),
+        fd => {
+            // Safe because libc::socket returned success
+            unsafe { Ok(OwnedFd::from_raw_fd(fd)) }
+        }
+    }
 }
 
 /// Create a pair of connected sockets
@@ -2087,7 +2096,7 @@ pub fn socketpair<T: Into<Option<SockProtocol>>>(
     ty: SockType,
     protocol: T,
     flags: SockFlag,
-) -> Result<(RawFd, RawFd)> {
+) -> Result<(OwnedFd, OwnedFd)> {
     let protocol = match protocol.into() {
         None => 0,
         Some(p) => p as c_int,
@@ -2106,14 +2115,18 @@ pub fn socketpair<T: Into<Option<SockProtocol>>>(
     };
     Errno::result(res)?;
 
-    Ok((fds[0], fds[1]))
+    // Safe because socketpair returned success.
+    unsafe {
+        Ok((OwnedFd::from_raw_fd(fds[0]), OwnedFd::from_raw_fd(fds[1])))
+    }
 }
 
 /// Listen for connections on a socket
 ///
 /// [Further reading](https://pubs.opengroup.org/onlinepubs/9699919799/functions/listen.html)
-pub fn listen(sockfd: RawFd, backlog: usize) -> Result<()> {
-    let res = unsafe { libc::listen(sockfd, backlog as c_int) };
+pub fn listen<F: AsFd>(sock: &F, backlog: usize) -> Result<()> {
+    let fd = sock.as_fd().as_raw_fd();
+    let res = unsafe { libc::listen(fd, backlog as c_int) };
 
     Errno::result(res).map(drop)
 }
@@ -2273,21 +2286,21 @@ pub trait GetSockOpt: Copy {
     type Val;
 
     /// Look up the value of this socket option on the given socket.
-    fn get(&self, fd: RawFd) -> Result<Self::Val>;
+    fn get<F: AsFd>(&self, fd: &F) -> Result<Self::Val>;
 }
 
 /// Represents a socket option that can be set.
 pub trait SetSockOpt: Clone {
     type Val;
 
     /// Set the value of this socket option on the given socket.
-    fn set(&self, fd: RawFd, val: &Self::Val) -> Result<()>;
+    fn set<F: AsFd>(&self, fd: &F, val: &Self::Val) -> Result<()>;
 }
 
 /// Get the current value for the requested socket option
 ///
 /// [Further reading](https://pubs.opengroup.org/onlinepubs/9699919799/functions/getsockopt.html)
-pub fn getsockopt<O: GetSockOpt>(fd: RawFd, opt: O) -> Result<O::Val> {
+pub fn getsockopt<F: AsFd, O: GetSockOpt>(fd: &F, opt: O) -> Result<O::Val> {
     opt.get(fd)
 }
 
@@ -2301,15 +2314,14 @@ pub fn getsockopt<O: GetSockOpt>(fd: RawFd, opt: O) -> Result<O::Val> {
 /// use nix::sys::socket::setsockopt;
 /// use nix::sys::socket::sockopt::KeepAlive;
 /// use std::net::TcpListener;
-/// use std::os::unix::io::AsRawFd;
 ///
 /// let listener = TcpListener::bind("0.0.0.0:0").unwrap();
-/// let fd = listener.as_raw_fd();
-/// let res = setsockopt(fd, KeepAlive, &true);
+/// let fd = listener;
+/// let res = setsockopt(&fd, KeepAlive, &true);
 /// assert!(res.is_ok());
 /// ```
-pub fn setsockopt<O: SetSockOpt>(
-    fd: RawFd,
+pub fn setsockopt<F: AsFd, O: SetSockOpt>(
+    fd: &F,
     opt: O,
     val: &O::Val,
 ) -> Result<()> {

src/sys/socket/sockopt.rs

@@ -9,7 +9,7 @@ use std::ffi::{OsStr, OsString};
 use std::mem::{self, MaybeUninit};
 #[cfg(target_family = "unix")]
 use std::os::unix::ffi::OsStrExt;
-use std::os::unix::io::RawFd;
+use std::os::unix::io::{AsFd, AsRawFd};
 
 // Constants
 // TCP_CA_NAME_MAX isn't defined in user space include files
@@ -44,12 +44,12 @@ macro_rules! setsockopt_impl {
         impl SetSockOpt for $name {
             type Val = $ty;
 
-            fn set(&self, fd: RawFd, val: &$ty) -> Result<()> {
+            fn set<F: AsFd>(&self, fd: &F, val: &$ty) -> Result<()> {
                 unsafe {
                     let setter: $setter = Set::new(val);
 
                     let res = libc::setsockopt(
-                        fd,
+                        fd.as_fd().as_raw_fd(),
                         $level,
                         $flag,
                         setter.ffi_ptr(),
@@ -89,12 +89,12 @@ macro_rules! getsockopt_impl {
         impl GetSockOpt for $name {
             type Val = $ty;
 
-            fn get(&self, fd: RawFd) -> Result<$ty> {
+            fn get<F: AsFd>(&self, fd: &F) -> Result<$ty> {
                 unsafe {
                     let mut getter: $getter = Get::uninit();
 
                     let res = libc::getsockopt(
-                        fd,
+                        fd.as_fd().as_raw_fd(),
                         $level,
                         $flag,
                         getter.ffi_ptr(),
@@ -1004,10 +1004,10 @@ pub struct AlgSetAeadAuthSize;
 impl SetSockOpt for AlgSetAeadAuthSize {
     type Val = usize;
 
-    fn set(&self, fd: RawFd, val: &usize) -> Result<()> {
+    fn set<F: AsFd>(&self, fd: &F, val: &usize) -> Result<()> {
         unsafe {
             let res = libc::setsockopt(
-                fd,
+                fd.as_fd().as_raw_fd(),
                 libc::SOL_ALG,
                 libc::ALG_SET_AEAD_AUTHSIZE,
                 ::std::ptr::null(),
@@ -1038,10 +1038,10 @@ where
 {
     type Val = T;
 
-    fn set(&self, fd: RawFd, val: &T) -> Result<()> {
+    fn set<F: AsFd>(&self, fd: &F, val: &T) -> Result<()> {
         unsafe {
             let res = libc::setsockopt(
-                fd,
+                fd.as_fd().as_raw_fd(),
                 libc::SOL_ALG,
                 libc::ALG_SET_KEY,
                 val.as_ref().as_ptr() as *const _,
@@ -1354,34 +1354,30 @@ mod test {
             SockFlag::empty(),
         )
         .unwrap();
-        let a_cred = getsockopt(a, super::PeerCredentials).unwrap();
-        let b_cred = getsockopt(b, super::PeerCredentials).unwrap();
+        let a_cred = getsockopt(&a, super::PeerCredentials).unwrap();
+        let b_cred = getsockopt(&b, super::PeerCredentials).unwrap();
         assert_eq!(a_cred, b_cred);
         assert_ne!(a_cred.pid(), 0);
     }
 
     #[test]
     fn is_socket_type_unix() {
         use super::super::*;
-        use crate::unistd::close;
 
-        let (a, b) = socketpair(
+        let (a, _b) = socketpair(
             AddressFamily::Unix,
             SockType::Stream,
             None,
             SockFlag::empty(),
         )
         .unwrap();
-        let a_type = getsockopt(a, super::SockType).unwrap();
+        let a_type = getsockopt(&a, super::SockType).unwrap();
         assert_eq!(a_type, SockType::Stream);
-        close(a).unwrap();
-        close(b).unwrap();
     }
 
     #[test]
     fn is_socket_type_dgram() {
         use super::super::*;
-        use crate::unistd::close;
 
         let s = socket(
             AddressFamily::Inet,
@@ -1390,16 +1386,14 @@ mod test {
             None,
         )
         .unwrap();
-        let s_type = getsockopt(s, super::SockType).unwrap();
+        let s_type = getsockopt(&s, super::SockType).unwrap();
         assert_eq!(s_type, SockType::Datagram);
-        close(s).unwrap();
     }
 
     #[cfg(any(target_os = "freebsd", target_os = "linux"))]
     #[test]
     fn can_get_listen_on_tcp_socket() {
         use super::super::*;
-        use crate::unistd::close;
 
         let s = socket(
             AddressFamily::Inet,
@@ -1408,11 +1402,10 @@ mod test {
             None,
         )
         .unwrap();
-        let s_listening = getsockopt(s, super::AcceptConn).unwrap();
+        let s_listening = getsockopt(&s, super::AcceptConn).unwrap();
         assert!(!s_listening);
-        listen(s, 10).unwrap();
-        let s_listening2 = getsockopt(s, super::AcceptConn).unwrap();
+        listen(&s, 10).unwrap();
+        let s_listening2 = getsockopt(&s, super::AcceptConn).unwrap();
         assert!(s_listening2);
-        close(s).unwrap();
     }
 }