Work around missing libc constants on Fuchsia

.github/workflows/main.yml

@@ -57,9 +57,8 @@ jobs:
     strategy:
       matrix:
         # TODO: add the following targets, currently broken.
-        # "x86_64-fuchsia"
         # "x86_64-unknown-redox"
-        target: ["aarch64-apple-ios", "aarch64-linux-android", "x86_64-apple-darwin", "x86_64-pc-windows-msvc", "x86_64-sun-solaris", "x86_64-unknown-freebsd", "x86_64-unknown-illumos", "x86_64-unknown-linux-gnu", "x86_64-unknown-netbsd"]
+        target: ["aarch64-apple-ios", "aarch64-linux-android", "x86_64-apple-darwin", "x86_64-fuchsia", "x86_64-pc-windows-msvc", "x86_64-sun-solaris", "x86_64-unknown-freebsd", "x86_64-unknown-illumos", "x86_64-unknown-linux-gnu", "x86_64-unknown-netbsd"]
     steps:
     - uses: actions/checkout@master
     - name: Install Rust

src/sys/unix.rs

@@ -7,11 +7,6 @@
 // except according to those terms.
 
 use std::cmp::min;
-#[cfg(all(
-    feature = "all",
-    any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-))]
-use std::ffi::{CStr, CString};
 #[cfg(not(target_os = "redox"))]
 use std::io::IoSlice;
 use std::marker::PhantomData;
@@ -942,11 +937,19 @@ impl crate::Socket {
         feature = "all",
         any(target_os = "android", target_os = "fuchsia", target_os = "linux")
     ))]
-    pub fn device(&self) -> io::Result<Option<CString>> {
+    pub fn device(&self) -> io::Result<Option<Vec<u8>>> {
+        use std::convert::TryInto as _;
+
+        // TODO(https://github.com/rust-lang/libc/pull/2010): Remove this.
+        #[cfg(target_os = "fuchsia")]
+        const IFNAMSIZ: libc::size_t = 16;
+
+        #[cfg(not(target_os = "fuchsia"))]
+        const IFNAMSIZ: libc::size_t = libc::IFNAMSIZ;
+
         // TODO: replace with `MaybeUninit::uninit_array` once stable.
-        let mut buf: [MaybeUninit<u8>; libc::IFNAMSIZ] =
-            unsafe { MaybeUninit::<[MaybeUninit<u8>; libc::IFNAMSIZ]>::uninit().assume_init() };
-        let mut len = buf.len() as libc::socklen_t;
+        let mut buf: MaybeUninit<[u8; IFNAMSIZ]> = MaybeUninit::uninit();
+        let mut len = IFNAMSIZ.try_into().unwrap();
         unsafe {
             syscall!(getsockopt(
                 self.inner,
@@ -959,21 +962,13 @@ impl crate::Socket {
         if len == 0 {
             Ok(None)
         } else {
-            // Allocate a buffer for `CString` with the length including the
-            // null terminator.
-            let len = len as usize;
-            let mut name = Vec::with_capacity(len);
-
             // TODO: use `MaybeUninit::slice_assume_init_ref` once stable.
             // Safety: `len` bytes are writen by the OS, this includes a null
             // terminator. However we don't copy the null terminator because
             // `CString::from_vec_unchecked` adds its own null terminator.
-            let buf = unsafe { slice::from_raw_parts(buf.as_ptr().cast(), len - 1) };
-            name.extend_from_slice(buf);
-
-            // Safety: the OS initialised the string for us, which shouldn't
-            // include any null bytes.
-            Ok(Some(unsafe { CString::from_vec_unchecked(name) }))
+            Ok(Some(
+                unsafe { buf.assume_init() }[..len.try_into().unwrap()].into(),
+            ))
         }
     }
 
@@ -990,9 +985,9 @@ impl crate::Socket {
         feature = "all",
         any(target_os = "android", target_os = "fuchsia", target_os = "linux")
     ))]
-    pub fn bind_device(&self, interface: Option<&CStr>) -> io::Result<()> {
+    pub fn bind_device(&self, interface: Option<&[u8]>) -> io::Result<()> {
         let (value, len) = if let Some(interface) = interface {
-            (interface.as_ptr(), interface.to_bytes_with_nul().len())
+            (interface.as_ptr(), interface.len())
         } else {
             (ptr::null(), 0)
         };
@@ -1058,9 +1053,15 @@ impl crate::Socket {
         any(target_os = "android", target_os = "fuchsia", target_os = "linux")
     ))]
     pub fn freebind(&self) -> io::Result<bool> {
+        // TODO(https://github.com/rust-lang/libc/pull/2011): Remove this.
+        #[cfg(target_os = "fuchsia")]
+        const IP_FREEBIND: c_int = 15;
+
+        #[cfg(not(target_os = "fuchsia"))]
+        const IP_FREEBIND: c_int = libc::IP_FREEBIND;
+
         unsafe {
-            getsockopt::<c_int>(self.inner, libc::SOL_SOCKET, libc::IP_FREEBIND)
-                .map(|reuse| reuse != 0)
+            getsockopt::<c_int>(self.inner, libc::SOL_SOCKET, IP_FREEBIND).map(|reuse| reuse != 0)
         }
     }
 
@@ -1078,14 +1079,14 @@ impl crate::Socket {
         any(target_os = "android", target_os = "fuchsia", target_os = "linux")
     ))]
     pub fn set_freebind(&self, reuse: bool) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.inner,
-                libc::SOL_SOCKET,
-                libc::IP_FREEBIND,
-                reuse as c_int,
-            )
-        }
+        // TODO(https://github.com/rust-lang/libc/pull/2011): Remove this.
+        #[cfg(target_os = "fuchsia")]
+        const IP_FREEBIND: c_int = 15;
+
+        #[cfg(not(target_os = "fuchsia"))]
+        const IP_FREEBIND: c_int = libc::IP_FREEBIND;
+
+        unsafe { setsockopt(self.inner, libc::SOL_SOCKET, IP_FREEBIND, reuse as c_int) }
     }
 }
 

tests/socket.rs

@@ -1,5 +1,3 @@
-#[cfg(all(feature = "all", any(target_os = "fuchsia", target_os = "linux")))]
-use std::ffi::CStr;
 #[cfg(any(windows, target_vendor = "apple"))]
 use std::io;
 #[cfg(not(target_os = "redox"))]
@@ -633,13 +631,13 @@ fn tcp_keepalive() {
 #[test]
 fn device() {
     // Some common network interface on Linux.
-    const INTERFACES: &[&str] = &["lo\0", "lo0\0", "eth0\0", "wlan0\0"];
+    const INTERFACES: &[&str] = &["lo", "lo0", "eth0", "wlan0"];
 
     let socket = Socket::new(Domain::IPV4, Type::STREAM, None).unwrap();
     assert_eq!(socket.device().unwrap(), None);
 
     for interface in INTERFACES.iter() {
-        let interface = CStr::from_bytes_with_nul(interface.as_bytes()).unwrap();
+        let interface = interface.as_bytes();
         if let Err(err) = socket.bind_device(Some(interface)) {
             // Network interface is not available try another.
             if matches!(err.raw_os_error(), Some(libc::ENODEV) | Some(libc::EPERM)) {