Make sockopt_impl! public

This allows users to define their own sockopts, instead of needing to
make a PR to Nix for every single one.

Fixes #577

Author: asomers

changelog/2557.added.md

@@ -0,0 +1,2 @@
+Added `sockopt_impl!` to the public API.  It's now possible for users to define
+their own sockopts without needing to make a PR to Nix.

src/sys/socket/sockopt.rs

@@ -1,18 +1,14 @@
 //! Socket options as used by `setsockopt` and `getsockopt`.
-use super::{GetSockOpt, SetSockOpt};
-use crate::errno::Errno;
 use crate::sys::time::TimeVal;
-use crate::Result;
 use cfg_if::cfg_if;
 use libc::{self, c_int, c_void, socklen_t};
-#[cfg(apple_targets)]
 use std::ffi::{CStr, CString};
 #[cfg(any(target_os = "freebsd", linux_android))]
 use std::ffi::{OsStr, OsString};
 use std::mem::{self, MaybeUninit};
 #[cfg(any(target_os = "freebsd", linux_android))]
 use std::os::unix::ffi::OsStrExt;
-use std::os::unix::io::{AsFd, AsRawFd};
+use std::os::unix::io::AsRawFd;
 
 // Constants
 // TCP_CA_NAME_MAX isn't defined in user space include files
@@ -26,8 +22,8 @@ const TCP_CA_NAME_MAX: usize = 16;
 /// This macro aims to help implementing `SetSockOpt` for different socket options that accept
 /// different kinds of data to be used with `setsockopt`.
 ///
-/// Instead of using this macro directly consider using `sockopt_impl!`, especially if the option
-/// you are implementing represents a simple type.
+/// Instead of using this macro directly consider using [`sockopt_impl!`](crate::sockopt_impl),
+/// especially if the option you are implementing represents a simple type.
 ///
 /// # Arguments
 ///
@@ -42,15 +38,22 @@ const TCP_CA_NAME_MAX: usize = 16;
 /// * Type of the value that you are going to set.
 /// * Type that implements the `Set` trait for the type from the previous item (like `SetBool` for
 ///    `bool`, `SetUsize` for `usize`, etc.).
+#[macro_export]
 macro_rules! setsockopt_impl {
     ($name:ident, $level:expr, $flag:path, $ty:ty, $setter:ty) => {
         #[allow(deprecated)] // to allow we have deprecated socket option
-        impl SetSockOpt for $name {
+        impl $crate::sys::socket::SetSockOpt for $name {
             type Val = $ty;
 
-            fn set<F: AsFd>(&self, fd: &F, val: &$ty) -> Result<()> {
+            fn set<F: std::os::unix::io::AsFd>(
+                &self,
+                fd: &F,
+                val: &$ty,
+            ) -> $crate::Result<()> {
+                use $crate::sys::socket::sockopt::Set;
                 unsafe {
-                    let setter: $setter = Set::new(val);
+                    let setter: $setter =
+                        $crate::sys::socket::sockopt::Set::new(val);
 
                     let res = libc::setsockopt(
                         fd.as_fd().as_raw_fd(),
@@ -59,7 +62,7 @@ macro_rules! setsockopt_impl {
                         setter.ffi_ptr(),
                         setter.ffi_len(),
                     );
-                    Errno::result(res).map(drop)
+                    $crate::errno::Errno::result(res).map(drop)
                 }
             }
         }
@@ -72,8 +75,8 @@ macro_rules! setsockopt_impl {
 /// This macro aims to help implementing `GetSockOpt` for different socket options that accept
 /// different kinds of data to be use with `getsockopt`.
 ///
-/// Instead of using this macro directly consider using `sockopt_impl!`, especially if the option
-/// you are implementing represents a simple type.
+/// Instead of using this macro directly consider using [`sockopt_impl!`](crate::sockopt_impl),
+/// especially if the option you are implementing represents a simple type.
 ///
 /// # Arguments
 ///
@@ -88,15 +91,21 @@ macro_rules! setsockopt_impl {
 /// * Type of the value that you are going to get.
 /// * Type that implements the `Get` trait for the type from the previous item (`GetBool` for
 ///    `bool`, `GetUsize` for `usize`, etc.).
+#[macro_export]
 macro_rules! getsockopt_impl {
     ($name:ident, $level:expr, $flag:path, $ty:ty, $getter:ty) => {
         #[allow(deprecated)] // to allow we have deprecated socket option
-        impl GetSockOpt for $name {
+        impl $crate::sys::socket::GetSockOpt for $name {
             type Val = $ty;
 
-            fn get<F: AsFd>(&self, fd: &F) -> Result<$ty> {
+            fn get<F: std::os::unix::io::AsFd>(
+                &self,
+                fd: &F,
+            ) -> $crate::Result<$ty> {
+                use $crate::sys::socket::sockopt::Get;
                 unsafe {
-                    let mut getter: $getter = Get::uninit();
+                    let mut getter: $getter =
+                        $crate::sys::socket::sockopt::Get::uninit();
 
                     let res = libc::getsockopt(
                         fd.as_fd().as_raw_fd(),
@@ -105,7 +114,7 @@ macro_rules! getsockopt_impl {
                         getter.ffi_ptr(),
                         getter.ffi_len(),
                     );
-                    Errno::result(res)?;
+                    $crate::errno::Errno::result(res)?;
 
                     match <$ty>::try_from(getter.assume_init()) {
                         // In most `getsockopt_impl!` implementations, `assume_init()`
@@ -122,7 +131,7 @@ macro_rules! getsockopt_impl {
                         // buffer type for this socket option, see issue:
                         // https://github.com/nix-rust/nix/issues/1819
                         #[allow(unreachable_patterns)]
-                        Err(_) => Err(Errno::EINVAL),
+                        Err(_) => Err($crate::errno::Errno::EINVAL),
                         Ok(r) => Ok(r),
                     }
                 }
@@ -158,58 +167,59 @@ macro_rules! getsockopt_impl {
 /// * `$setter:ty`: `Set` implementation; optional; only for `SetOnly` and `Both`.
 // Some targets don't use all rules.
 #[allow(unused_macro_rules)]
+#[macro_export]
 macro_rules! sockopt_impl {
     ($(#[$attr:meta])* $name:ident, GetOnly, $level:expr, $flag:path, bool) => {
         sockopt_impl!($(#[$attr])*
-                      $name, GetOnly, $level, $flag, bool, GetBool);
+                      $name, GetOnly, $level, $flag, bool, $crate::sys::socket::sockopt::GetBool);
     };
 
     ($(#[$attr:meta])* $name:ident, GetOnly, $level:expr, $flag:path, u8) => {
-        sockopt_impl!($(#[$attr])* $name, GetOnly, $level, $flag, u8, GetU8);
+        sockopt_impl!($(#[$attr])* $name, GetOnly, $level, $flag, u8, $crate::sys::socket::sockopt::GetU8);
     };
 
     ($(#[$attr:meta])* $name:ident, GetOnly, $level:expr, $flag:path, usize) =>
     {
         sockopt_impl!($(#[$attr])*
-                      $name, GetOnly, $level, $flag, usize, GetUsize);
+                      $name, GetOnly, $level, $flag, usize, $crate::sys::socket::sockopt::GetUsize);
     };
 
     ($(#[$attr:meta])* $name:ident, SetOnly, $level:expr, $flag:path, bool) => {
         sockopt_impl!($(#[$attr])*
-                      $name, SetOnly, $level, $flag, bool, SetBool);
+                      $name, SetOnly, $level, $flag, bool, $crate::sys::socket::sockopt::SetBool);
     };
 
     ($(#[$attr:meta])* $name:ident, SetOnly, $level:expr, $flag:path, u8) => {
-        sockopt_impl!($(#[$attr])* $name, SetOnly, $level, $flag, u8, SetU8);
+        sockopt_impl!($(#[$attr])* $name, SetOnly, $level, $flag, u8, $crate::sys::socket::sockopt::SetU8);
     };
 
     ($(#[$attr:meta])* $name:ident, SetOnly, $level:expr, $flag:path, usize) =>
     {
         sockopt_impl!($(#[$attr])*
-                      $name, SetOnly, $level, $flag, usize, SetUsize);
+                      $name, SetOnly, $level, $flag, usize, $crate::sys::socket::sockopt::SetUsize);
     };
 
     ($(#[$attr:meta])* $name:ident, Both, $level:expr, $flag:path, bool) => {
         sockopt_impl!($(#[$attr])*
-                      $name, Both, $level, $flag, bool, GetBool, SetBool);
+                      $name, Both, $level, $flag, bool, $crate::sys::socket::sockopt::GetBool, $crate::sys::socket::sockopt::SetBool);
     };
 
     ($(#[$attr:meta])* $name:ident, Both, $level:expr, $flag:path, u8) => {
         sockopt_impl!($(#[$attr])*
-                      $name, Both, $level, $flag, u8, GetU8, SetU8);
+                      $name, Both, $level, $flag, u8, $crate::sys::socket::sockopt::GetU8, $crate::sys::socket::sockopt::SetU8);
     };
 
     ($(#[$attr:meta])* $name:ident, Both, $level:expr, $flag:path, usize) => {
         sockopt_impl!($(#[$attr])*
-                      $name, Both, $level, $flag, usize, GetUsize, SetUsize);
+                      $name, Both, $level, $flag, usize, $crate::sys::socket::sockopt::GetUsize, $crate::sys::socket::sockopt::SetUsize);
     };
 
     ($(#[$attr:meta])* $name:ident, Both, $level:expr, $flag:path,
      OsString<$array:ty>) =>
     {
         sockopt_impl!($(#[$attr])*
-                      $name, Both, $level, $flag, OsString, GetOsString<$array>,
-                      SetOsString);
+                      $name, Both, $level, $flag, std::ffi::OsString, $crate::sys::socket::sockopt::GetOsString<$array>,
+                      $crate::sys::socket::sockopt::SetOsString);
     };
 
     /*
@@ -219,7 +229,7 @@ macro_rules! sockopt_impl {
     ($(#[$attr:meta])* $name:ident, GetOnly, $level:expr, $flag:path, $ty:ty) =>
     {
         sockopt_impl!($(#[$attr])*
-                      $name, GetOnly, $level, $flag, $ty, GetStruct<$ty>);
+                      $name, GetOnly, $level, $flag, $ty, $crate::sys::socket::sockopt::GetStruct<$ty>);
     };
 
     ($(#[$attr:meta])* $name:ident, GetOnly, $level:expr, $flag:path, $ty:ty,
@@ -235,7 +245,7 @@ macro_rules! sockopt_impl {
     ($(#[$attr:meta])* $name:ident, SetOnly, $level:expr, $flag:path, $ty:ty) =>
     {
         sockopt_impl!($(#[$attr])*
-                      $name, SetOnly, $level, $flag, $ty, SetStruct<$ty>);
+                      $name, SetOnly, $level, $flag, $ty, $crate::sys::socket::sockopt::SetStruct<$ty>);
     };
 
     ($(#[$attr:meta])* $name:ident, SetOnly, $level:expr, $flag:path, $ty:ty,
@@ -261,8 +271,8 @@ macro_rules! sockopt_impl {
 
     ($(#[$attr:meta])* $name:ident, Both, $level:expr, $flag:path, $ty:ty) => {
         sockopt_impl!($(#[$attr])*
-                      $name, Both, $level, $flag, $ty, GetStruct<$ty>,
-                      SetStruct<$ty>);
+                      $name, Both, $level, $flag, $ty, $crate::sys::socket::sockopt::GetStruct<$ty>,
+                      $crate::sys::socket::sockopt::SetStruct<$ty>);
     };
 }
 
@@ -1437,7 +1447,9 @@ impl SetSockOpt for TcpTlsRx {
  */
 
 /// Helper trait that describes what is expected from a `GetSockOpt` getter.
-trait Get<T> {
+// Hide the docs, because it's an implementation detail of `sockopt_impl!`
+#[doc(hidden)]
+pub trait Get<T> {
     /// Returns an uninitialized value.
     fn uninit() -> Self;
     /// Returns a pointer to the stored value. This pointer will be passed to the system's
@@ -1451,7 +1463,9 @@ trait Get<T> {
 }
 
 /// Helper trait that describes what is expected from a `SetSockOpt` setter.
-trait Set<'a, T> {
+// Hide the docs, because it's an implementation detail of `sockopt_impl!`
+#[doc(hidden)]
+pub trait Set<'a, T> {
     /// Initialize the setter with a given value.
     fn new(val: &'a T) -> Self;
     /// Returns a pointer to the stored value. This pointer will be passed to the system's
@@ -1463,7 +1477,10 @@ trait Set<'a, T> {
 }
 
 /// Getter for an arbitrary `struct`.
-struct GetStruct<T> {
+// Hide the docs, because it's an implementation detail of `sockopt_impl!`
+#[doc(hidden)]
+#[derive(Debug)]
+pub struct GetStruct<T> {
     len: socklen_t,
     val: MaybeUninit<T>,
 }
@@ -1495,7 +1512,10 @@ impl<T> Get<T> for GetStruct<T> {
 }
 
 /// Setter for an arbitrary `struct`.
-struct SetStruct<'a, T: 'static> {
+// Hide the docs, because it's an implementation detail of `sockopt_impl!`
+#[doc(hidden)]
+#[derive(Debug)]
+pub struct SetStruct<'a, T: 'static> {
     ptr: &'a T,
 }
 
@@ -1514,7 +1534,10 @@ impl<'a, T> Set<'a, T> for SetStruct<'a, T> {
 }
 
 /// Getter for a boolean value.
-struct GetBool {
+// Hide the docs, because it's an implementation detail of `sockopt_impl!`
+#[doc(hidden)]
+#[derive(Clone, Copy, Debug)]
+pub struct GetBool {
     len: socklen_t,
     val: MaybeUninit<c_int>,
 }
@@ -1546,7 +1569,10 @@ impl Get<bool> for GetBool {
 }
 
 /// Setter for a boolean value.
-struct SetBool {
+// Hide the docs, because it's an implementation detail of `sockopt_impl!`
+#[doc(hidden)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct SetBool {
     val: c_int,
 }
 
@@ -1568,7 +1594,10 @@ impl<'a> Set<'a, bool> for SetBool {
 
 /// Getter for an `u8` value.
 #[cfg(feature = "net")]
-struct GetU8 {
+// Hide the docs, because it's an implementation detail of `sockopt_impl!`
+#[doc(hidden)]
+#[derive(Clone, Copy, Debug)]
+pub struct GetU8 {
     len: socklen_t,
     val: MaybeUninit<u8>,
 }
@@ -1601,7 +1630,9 @@ impl Get<u8> for GetU8 {
 }
 
 /// Setter for an `u8` value.
-#[cfg(feature = "net")]
+// Hide the docs, because it's an implementation detail of `sockopt_impl!`
+#[doc(hidden)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
 struct SetU8 {
     val: u8,
 }
@@ -1622,7 +1653,10 @@ impl<'a> Set<'a, u8> for SetU8 {
 }
 
 /// Getter for an `usize` value.
-struct GetUsize {
+// Hide the docs, because it's an implementation detail of `sockopt_impl!`
+#[doc(hidden)]
+#[derive(Clone, Copy, Debug)]
+pub struct GetUsize {
     len: socklen_t,
     val: MaybeUninit<c_int>,
 }
@@ -1654,7 +1688,10 @@ impl Get<usize> for GetUsize {
 }
 
 /// Setter for an `usize` value.
-struct SetUsize {
+// Hide the docs, because it's an implementation detail of `sockopt_impl!`
+#[doc(hidden)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct SetUsize {
     val: c_int,
 }
 
@@ -1673,8 +1710,10 @@ impl<'a> Set<'a, usize> for SetUsize {
 }
 
 /// Getter for a `OsString` value.
-#[cfg(any(target_os = "freebsd", linux_android))]
-struct GetOsString<T: AsMut<[u8]>> {
+// Hide the docs, because it's an implementation detail of `sockopt_impl!`
+#[doc(hidden)]
+#[derive(Debug)]
+pub struct GetOsString<T: AsMut<[u8]>> {
     len: socklen_t,
     val: MaybeUninit<T>,
 }
@@ -1704,8 +1743,10 @@ impl<T: AsMut<[u8]>> Get<OsString> for GetOsString<T> {
 }
 
 /// Setter for a `OsString` value.
-#[cfg(any(target_os = "freebsd", linux_android))]
-struct SetOsString<'a> {
+// Hide the docs, because it's an implementation detail of `sockopt_impl!`
+#[doc(hidden)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct SetOsString<'a> {
     val: &'a OsStr,
 }
 
@@ -1727,14 +1768,14 @@ impl<'a> Set<'a, OsString> for SetOsString<'a> {
 }
 
 /// Getter for a `CString` value.
-#[cfg(apple_targets)]
-#[cfg(feature = "net")]
-struct GetCString<T: AsMut<[u8]>> {
+// Hide the docs, because it's an implementation detail of `sockopt_impl!`
+#[doc(hidden)]
+#[derive(Debug)]
+pub struct GetCString<T: AsMut<[u8]>> {
     len: socklen_t,
     val: MaybeUninit<T>,
 }
 
-#[cfg(apple_targets)]
 #[cfg(feature = "net")]
 impl<T: AsMut<[u8]>> Get<CString> for GetCString<T> {
     fn uninit() -> Self {