Factor out a SocketAddrArg::write_sockaddr function. (#1334)

This is needed by c-scape in order to encode socket addresses into
libc-compatible form.

And a few other minor cleanups.

Author: sunfishcode

src/net/addr.rs

@@ -68,19 +68,34 @@ pub unsafe trait SocketAddrArg {
 
     /// Convert to `SocketAddrAny`.
     fn as_any(&self) -> SocketAddrAny {
-        // SAFETY: The closure dereferences exactly `len` bytes at `ptr`.
+        let mut storage = MaybeUninit::<SocketAddrStorage>::uninit();
+        // SAFETY: We've allocated `storage` here, we're writing to it, and
+        // we're using the number of bytes written.
         unsafe {
-            self.with_sockaddr(|ptr, len| {
-                let mut storage = MaybeUninit::<SocketAddrStorage>::uninit();
-                ptr::copy_nonoverlapping(
-                    ptr.cast::<u8>(),
-                    storage.as_mut_ptr().cast::<u8>(),
-                    len as usize,
-                );
-                SocketAddrAny::new(storage, len)
-            })
+            let len = self.write_sockaddr(storage.as_mut_ptr());
+            SocketAddrAny::new(storage, len)
         }
     }
+
+    /// Encode an address into a `SocketAddrStorage`.
+    ///
+    /// Returns the number of bytes that were written.
+    ///
+    /// For a safe interface to this functionality, use [`as_any`].
+    ///
+    /// [`as_any`]: Self::as_any
+    ///
+    /// # Safety
+    ///
+    /// `storage` must be valid to write up to `size_of<SocketAddrStorage>()`
+    /// bytes to.
+    unsafe fn write_sockaddr(&self, storage: *mut SocketAddrStorage) -> SocketAddrLen {
+        // The closure dereferences exactly `len` bytes at `ptr`.
+        self.with_sockaddr(|ptr, len| {
+            ptr::copy_nonoverlapping(ptr.cast::<u8>(), storage.cast::<u8>(), len as usize);
+            len
+        })
+    }
 }
 
 /// Helper for implementing SocketAddrArg::with_sockaddr

src/net/socket_addr_any.rs

@@ -16,6 +16,9 @@ use core::num::NonZeroU32;
 
 /// Temporary buffer for creating a `SocketAddrAny` from a
 /// syscall that writes to a `sockaddr_t` and `socklen_t`
+///
+/// Unlike `SocketAddrAny`, this does not maintain the invariant that `len`
+/// bytes are initialized.
 pub(crate) struct SocketAddrBuf {
     pub(crate) len: c::socklen_t,
     pub(crate) storage: MaybeUninit<SocketAddrStorage>,
@@ -38,7 +41,7 @@ impl SocketAddrBuf {
     /// and its length written into `self.len`.
     #[inline]
     pub(crate) unsafe fn into_any(self) -> SocketAddrAny {
-        SocketAddrAny::new(self.storage, self.len.try_into().unwrap())
+        SocketAddrAny::new(self.storage, bitcast!(self.len))
     }
 
     /// Convert the buffer into [`Option<SocketAddrAny>`].
@@ -53,7 +56,7 @@ impl SocketAddrBuf {
     /// have been set to 0.
     #[inline]
     pub(crate) unsafe fn into_any_option(self) -> Option<SocketAddrAny> {
-        let len = self.len.try_into().unwrap();
+        let len = bitcast!(self.len);
         if read_sockaddr::sockaddr_nonempty(self.storage.as_ptr().cast(), len) {
             Some(SocketAddrAny::new(self.storage, len))
         } else {

src/process/types.rs

@@ -1,4 +1,6 @@
 //! Types for use with [`rustix::process`] functions.
+//!
+//! [`rustix::process`]: crate::process
 
 #![allow(unsafe_code)]
 

tests/net/unix.rs

@@ -418,7 +418,6 @@ fn test_abstract_unix_msg_unconnected() {
     do_test_unix_msg_unconnected(name);
 }
 
-#[cfg(feature = "pipe")]
 #[cfg(not(any(target_os = "redox", target_os = "wasi")))]
 #[cfg(feature = "pipe")]
 #[test]
@@ -715,7 +714,6 @@ fn test_unix_peercred_implicit() {
 
 /// Like `test_unix_msg_with_scm_rights`, but with multiple file descriptors
 /// over multiple control messages.
-#[cfg(feature = "pipe")]
 #[cfg(not(any(target_os = "redox", target_os = "wasi")))]
 #[cfg(feature = "pipe")]
 #[test]

tests/net/unix_alloc.rs

@@ -416,7 +416,6 @@ fn test_abstract_unix_msg_unconnected() {
     do_test_unix_msg_unconnected(name);
 }
 
-#[cfg(feature = "pipe")]
 #[cfg(not(any(target_os = "redox", target_os = "wasi")))]
 #[cfg(feature = "pipe")]
 #[test]
@@ -656,7 +655,6 @@ fn test_unix_peercred() {
 
 /// Like `test_unix_msg_with_scm_rights`, but with multiple file descriptors
 /// over multiple control messages.
-#[cfg(feature = "pipe")]
 #[cfg(not(any(target_os = "redox", target_os = "wasi")))]
 #[cfg(feature = "pipe")]
 #[test]

tests/termios/termios.rs

@@ -120,6 +120,20 @@ fn test_termios_modes() {
     assert!(new_tio.output_modes.contains(OutputModes::ONOCR));
     assert!(new_tio.input_modes.contains(InputModes::IGNBRK));
     assert!(new_tio.control_modes.contains(ControlModes::CLOCAL));
+
+    tio.local_modes.remove(LocalModes::TOSTOP);
+    tio.output_modes.remove(OutputModes::ONOCR);
+    tio.input_modes.remove(InputModes::IGNBRK);
+    tio.control_modes.remove(ControlModes::CLOCAL);
+
+    tcsetattr(&pty, OptionalActions::Now, &tio).unwrap();
+
+    let new_tio = tcgetattr(&pty).unwrap();
+
+    assert!(!new_tio.local_modes.contains(LocalModes::TOSTOP));
+    assert!(!new_tio.output_modes.contains(OutputModes::ONOCR));
+    assert!(!new_tio.input_modes.contains(InputModes::IGNBRK));
+    assert!(!new_tio.control_modes.contains(ControlModes::CLOCAL));
 }
 
 // Disable on illumos where `tcgetattr` doesn't appear to support