Runtime removal: refactor pipes and networking

This patch continues the runtime removal by moving pipe and
networking-related code into `sys`.

Because this eliminates APIs in `libnative` and `librustrt`, it is a:

[breaking-change]

This functionality is likely to be available publicly, in some form,
from `std` in the future.

1 files changed, 909 insertions, 0 deletions

diff --git a/src/libstd/sys/common/net.rs b/src/libstd/sys/common/net.rs
new file mode 100644
index 00000000000..0559005100f
--- /dev/null
+++ b/src/libstd/sys/common/net.rs
@@ -0,0 +1,909 @@
+// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use alloc::arc::Arc;
+use libc::{mod, c_char, c_int};
+use mem;
+use ptr::{mod, null, null_mut};
+use rt::mutex;
+use io::net::ip::{SocketAddr, IpAddr, Ipv4Addr, Ipv6Addr};
+use io::net::addrinfo;
+use io::{IoResult, IoError};
+use sys::{mod, retry, c, sock_t, last_error, last_net_error, last_gai_error, close_sock,
+          wrlen, msglen_t, os, wouldblock, set_nonblocking, timer, ms_to_timeval,
+          decode_error_detailed};
+use sys_common::{mod, keep_going, short_write, timeout};
+use prelude::*;
+use cmp;
+use io;
+
+#[deriving(Show)]
+pub enum SocketStatus {
+    Readable,
+    Writable,
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// sockaddr and misc bindings
+////////////////////////////////////////////////////////////////////////////////
+
+pub fn htons(u: u16) -> u16 {
+    u.to_be()
+}
+pub fn ntohs(u: u16) -> u16 {
+    Int::from_be(u)
+}
+
+pub enum InAddr {
+    In4Addr(libc::in_addr),
+    In6Addr(libc::in6_addr),
+}
+
+pub fn ip_to_inaddr(ip: IpAddr) -> InAddr {
+    match ip {
+        Ipv4Addr(a, b, c, d) => {
+            let ip = (a as u32 << 24) |
+                     (b as u32 << 16) |
+                     (c as u32 <<  8) |
+                     (d as u32 <<  0);
+            In4Addr(libc::in_addr {
+                s_addr: Int::from_be(ip)
+            })
+        }
+        Ipv6Addr(a, b, c, d, e, f, g, h) => {
+            In6Addr(libc::in6_addr {
+                s6_addr: [
+                    htons(a),
+                    htons(b),
+                    htons(c),
+                    htons(d),
+                    htons(e),
+                    htons(f),
+                    htons(g),
+                    htons(h),
+                ]
+            })
+        }
+    }
+}
+
+pub fn addr_to_sockaddr(addr: SocketAddr,
+                    storage: &mut libc::sockaddr_storage)
+                    -> libc::socklen_t {
+    unsafe {
+        let len = match ip_to_inaddr(addr.ip) {
+            In4Addr(inaddr) => {
+                let storage = storage as *mut _ as *mut libc::sockaddr_in;
+                (*storage).sin_family = libc::AF_INET as libc::sa_family_t;
+                (*storage).sin_port = htons(addr.port);
+                (*storage).sin_addr = inaddr;
+                mem::size_of::<libc::sockaddr_in>()
+            }
+            In6Addr(inaddr) => {
+                let storage = storage as *mut _ as *mut libc::sockaddr_in6;
+                (*storage).sin6_family = libc::AF_INET6 as libc::sa_family_t;
+                (*storage).sin6_port = htons(addr.port);
+                (*storage).sin6_addr = inaddr;
+                mem::size_of::<libc::sockaddr_in6>()
+            }
+        };
+        return len as libc::socklen_t;
+    }
+}
+
+pub fn socket(addr: SocketAddr, ty: libc::c_int) -> IoResult<sock_t> {
+    unsafe {
+        let fam = match addr.ip {
+            Ipv4Addr(..) => libc::AF_INET,
+            Ipv6Addr(..) => libc::AF_INET6,
+        };
+        match libc::socket(fam, ty, 0) {
+            -1 => Err(last_net_error()),
+            fd => Ok(fd),
+        }
+    }
+}
+
+pub fn setsockopt<T>(fd: sock_t, opt: libc::c_int, val: libc::c_int,
+                 payload: T) -> IoResult<()> {
+    unsafe {
+        let payload = &payload as *const T as *const libc::c_void;
+        let ret = libc::setsockopt(fd, opt, val,
+                                   payload,
+                                   mem::size_of::<T>() as libc::socklen_t);
+        if ret != 0 {
+            Err(last_net_error())
+        } else {
+            Ok(())
+        }
+    }
+}
+
+pub fn getsockopt<T: Copy>(fd: sock_t, opt: libc::c_int,
+                           val: libc::c_int) -> IoResult<T> {
+    unsafe {
+        let mut slot: T = mem::zeroed();
+        let mut len = mem::size_of::<T>() as libc::socklen_t;
+        let ret = c::getsockopt(fd, opt, val,
+                                &mut slot as *mut _ as *mut _,
+                                &mut len);
+        if ret != 0 {
+            Err(last_net_error())
+        } else {
+            assert!(len as uint == mem::size_of::<T>());
+            Ok(slot)
+        }
+    }
+}
+
+pub fn sockname(fd: sock_t,
+            f: unsafe extern "system" fn(sock_t, *mut libc::sockaddr,
+                                         *mut libc::socklen_t) -> libc::c_int)
+    -> IoResult<SocketAddr>
+{
+    let mut storage: libc::sockaddr_storage = unsafe { mem::zeroed() };
+    let mut len = mem::size_of::<libc::sockaddr_storage>() as libc::socklen_t;
+    unsafe {
+        let storage = &mut storage as *mut libc::sockaddr_storage;
+        let ret = f(fd,
+                    storage as *mut libc::sockaddr,
+                    &mut len as *mut libc::socklen_t);
+        if ret != 0 {
+            return Err(last_net_error())
+        }
+    }
+    return sockaddr_to_addr(&storage, len as uint);
+}
+
+pub fn sockaddr_to_addr(storage: &libc::sockaddr_storage,
+                        len: uint) -> IoResult<SocketAddr> {
+    match storage.ss_family as libc::c_int {
+        libc::AF_INET => {
+            assert!(len as uint >= mem::size_of::<libc::sockaddr_in>());
+            let storage: &libc::sockaddr_in = unsafe {
+                mem::transmute(storage)
+            };
+            let ip = (storage.sin_addr.s_addr as u32).to_be();
+            let a = (ip >> 24) as u8;
+            let b = (ip >> 16) as u8;
+            let c = (ip >>  8) as u8;
+            let d = (ip >>  0) as u8;
+            Ok(SocketAddr {
+                ip: Ipv4Addr(a, b, c, d),
+                port: ntohs(storage.sin_port),
+            })
+        }
+        libc::AF_INET6 => {
+            assert!(len as uint >= mem::size_of::<libc::sockaddr_in6>());
+            let storage: &libc::sockaddr_in6 = unsafe {
+                mem::transmute(storage)
+            };
+            let a = ntohs(storage.sin6_addr.s6_addr[0]);
+            let b = ntohs(storage.sin6_addr.s6_addr[1]);
+            let c = ntohs(storage.sin6_addr.s6_addr[2]);
+            let d = ntohs(storage.sin6_addr.s6_addr[3]);
+            let e = ntohs(storage.sin6_addr.s6_addr[4]);
+            let f = ntohs(storage.sin6_addr.s6_addr[5]);
+            let g = ntohs(storage.sin6_addr.s6_addr[6]);
+            let h = ntohs(storage.sin6_addr.s6_addr[7]);
+            Ok(SocketAddr {
+                ip: Ipv6Addr(a, b, c, d, e, f, g, h),
+                port: ntohs(storage.sin6_port),
+            })
+        }
+        _ => {
+            Err(IoError {
+                kind: io::InvalidInput,
+                desc: "invalid argument",
+                detail: None,
+            })
+        }
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// get_host_addresses
+////////////////////////////////////////////////////////////////////////////////
+
+extern "system" {
+    fn getaddrinfo(node: *const c_char, service: *const c_char,
+                   hints: *const libc::addrinfo,
+                   res: *mut *mut libc::addrinfo) -> c_int;
+    fn freeaddrinfo(res: *mut libc::addrinfo);
+}
+
+pub fn get_host_addresses(host: Option<&str>, servname: Option<&str>,
+                          hint: Option<addrinfo::Hint>)
+                          -> Result<Vec<addrinfo::Info>, IoError>
+{
+    sys::init_net();
+
+    assert!(host.is_some() || servname.is_some());
+
+    let c_host = host.map(|x| x.to_c_str());
+    let c_host = c_host.as_ref().map(|x| x.as_ptr()).unwrap_or(null());
+    let c_serv = servname.map(|x| x.to_c_str());
+    let c_serv = c_serv.as_ref().map(|x| x.as_ptr()).unwrap_or(null());
+
+    let hint = hint.map(|hint| {
+        libc::addrinfo {
+            ai_flags: hint.flags as c_int,
+            ai_family: hint.family as c_int,
+            ai_socktype: 0,
+            ai_protocol: 0,
+            ai_addrlen: 0,
+            ai_canonname: null_mut(),
+            ai_addr: null_mut(),
+            ai_next: null_mut()
+        }
+    });
+
+    let hint_ptr = hint.as_ref().map_or(null(), |x| {
+        x as *const libc::addrinfo
+    });
+    let mut res = null_mut();
+
+    // Make the call
+    let s = unsafe {
+        getaddrinfo(c_host, c_serv, hint_ptr, &mut res)
+    };
+
+    // Error?
+    if s != 0 {
+        return Err(last_gai_error(s));
+    }
+
+    // Collect all the results we found
+    let mut addrs = Vec::new();
+    let mut rp = res;
+    while rp.is_not_null() {
+        unsafe {
+            let addr = try!(sockaddr_to_addr(mem::transmute((*rp).ai_addr),
+                                             (*rp).ai_addrlen as uint));
+            addrs.push(addrinfo::Info {
+                address: addr,
+                family: (*rp).ai_family as uint,
+                socktype: None,
+                protocol: None,
+                flags: (*rp).ai_flags as uint
+            });
+
+            rp = (*rp).ai_next as *mut libc::addrinfo;
+        }
+    }
+
+    unsafe { freeaddrinfo(res); }
+
+    Ok(addrs)
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Timeout helpers
+//
+// The read/write functions below are the helpers for reading/writing a socket
+// with a possible deadline specified. This is generally viewed as a timed out
+// I/O operation.
+//
+// From the application's perspective, timeouts apply to the I/O object, not to
+// the underlying file descriptor (it's one timeout per object). This means that
+// we can't use the SO_RCVTIMEO and corresponding send timeout option.
+//
+// The next idea to implement timeouts would be to use nonblocking I/O. An
+// invocation of select() would wait (with a timeout) for a socket to be ready.
+// Once its ready, we can perform the operation. Note that the operation *must*
+// be nonblocking, even though select() says the socket is ready. This is
+// because some other thread could have come and stolen our data (handles can be
+// cloned).
+//
+// To implement nonblocking I/O, the first option we have is to use the
+// O_NONBLOCK flag. Remember though that this is a global setting, affecting all
+// I/O objects, so this was initially viewed as unwise.
+//
+// It turns out that there's this nifty MSG_DONTWAIT flag which can be passed to
+// send/recv, but the niftiness wears off once you realize it only works well on
+// Linux [1] [2]. This means that it's pretty easy to get a nonblocking
+// operation on Linux (no flag fiddling, no affecting other objects), but not on
+// other platforms.
+//
+// To work around this constraint on other platforms, we end up using the
+// original strategy of flipping the O_NONBLOCK flag. As mentioned before, this
+// could cause other objects' blocking operations to suddenly become
+// nonblocking. To get around this, a "blocking operation" which returns EAGAIN
+// falls back to using the same code path as nonblocking operations, but with an
+// infinite timeout (select + send/recv). This helps emulate blocking
+// reads/writes despite the underlying descriptor being nonblocking, as well as
+// optimizing the fast path of just hitting one syscall in the good case.
+//
+// As a final caveat, this implementation uses a mutex so only one thread is
+// doing a nonblocking operation at at time. This is the operation that comes
+// after the select() (at which point we think the socket is ready). This is
+// done for sanity to ensure that the state of the O_NONBLOCK flag is what we
+// expect (wouldn't want someone turning it on when it should be off!). All
+// operations performed in the lock are *nonblocking* to avoid holding the mutex
+// forever.
+//
+// So, in summary, Linux uses MSG_DONTWAIT and doesn't need mutexes, everyone
+// else uses O_NONBLOCK and mutexes with some trickery to make sure blocking
+// reads/writes are still blocking.
+//
+// Fun, fun!
+//
+// [1] http://twistedmatrix.com/pipermail/twisted-commits/2012-April/034692.html
+// [2] http://stackoverflow.com/questions/19819198/does-send-msg-dontwait
+
+pub fn read<T>(fd: sock_t,
+               deadline: u64,
+               lock: || -> T,
+               read: |bool| -> libc::c_int) -> IoResult<uint> {
+    let mut ret = -1;
+    if deadline == 0 {
+        ret = retry(|| read(false));
+    }
+
+    if deadline != 0 || (ret == -1 && wouldblock()) {
+        let deadline = match deadline {
+            0 => None,
+            n => Some(n),
+        };
+        loop {
+            // With a timeout, first we wait for the socket to become
+            // readable using select(), specifying the relevant timeout for
+            // our previously set deadline.
+            try!(await([fd], deadline, Readable));
+
+            // At this point, we're still within the timeout, and we've
+            // determined that the socket is readable (as returned by
+            // select). We must still read the socket in *nonblocking* mode
+            // because some other thread could come steal our data. If we
+            // fail to read some data, we retry (hence the outer loop) and
+            // wait for the socket to become readable again.
+            let _guard = lock();
+            match retry(|| read(deadline.is_some())) {
+                -1 if wouldblock() => {}
+                -1 => return Err(last_net_error()),
+               n => { ret = n; break }
+            }
+        }
+    }
+
+    match ret {
+        0 => Err(sys_common::eof()),
+        n if n < 0 => Err(last_net_error()),
+        n => Ok(n as uint)
+    }
+}
+
+pub fn write<T>(fd: sock_t,
+                deadline: u64,
+                buf: &[u8],
+                write_everything: bool,
+                lock: || -> T,
+                write: |bool, *const u8, uint| -> i64) -> IoResult<uint> {
+    let mut ret = -1;
+    let mut written = 0;
+    if deadline == 0 {
+        if write_everything {
+            ret = keep_going(buf, |inner, len| {
+                written = buf.len() - len;
+                write(false, inner, len)
+            });
+        } else {
+            ret = retry(|| { write(false, buf.as_ptr(), buf.len()) });
+            if ret > 0 { written = ret as uint; }
+        }
+    }
+
+    if deadline != 0 || (ret == -1 && wouldblock()) {
+        let deadline = match deadline {
+            0 => None,
+            n => Some(n),
+        };
+        while written < buf.len() && (write_everything || written == 0) {
+            // As with read(), first wait for the socket to be ready for
+            // the I/O operation.
+            match await([fd], deadline, Writable) {
+                Err(ref e) if e.kind == io::EndOfFile && written > 0 => {
+                    assert!(deadline.is_some());
+                    return Err(short_write(written, "short write"))
+                }
+                Err(e) => return Err(e),
+                Ok(()) => {}
+            }
+
+            // Also as with read(), we use MSG_DONTWAIT to guard ourselves
+            // against unforeseen circumstances.
+            let _guard = lock();
+            let ptr = buf[written..].as_ptr();
+            let len = buf.len() - written;
+            match retry(|| write(deadline.is_some(), ptr, len)) {
+                -1 if wouldblock() => {}
+                -1 => return Err(last_net_error()),
+                n => { written += n as uint; }
+            }
+        }
+        ret = 0;
+    }
+    if ret < 0 {
+        Err(last_net_error())
+    } else {
+        Ok(written)
+    }
+}
+
+// See http://developerweb.net/viewtopic.php?id=3196 for where this is
+// derived from.
+pub fn connect_timeout(fd: sock_t,
+                       addrp: *const libc::sockaddr,
+                       len: libc::socklen_t,
+                       timeout_ms: u64) -> IoResult<()> {
+    #[cfg(unix)]    use libc::EINPROGRESS as INPROGRESS;
+    #[cfg(windows)] use libc::WSAEINPROGRESS as INPROGRESS;
+    #[cfg(unix)]    use libc::EWOULDBLOCK as WOULDBLOCK;
+    #[cfg(windows)] use libc::WSAEWOULDBLOCK as WOULDBLOCK;
+
+    // Make sure the call to connect() doesn't block
+    try!(set_nonblocking(fd, true));
+
+    let ret = match unsafe { libc::connect(fd, addrp, len) } {
+        // If the connection is in progress, then we need to wait for it to
+        // finish (with a timeout). The current strategy for doing this is
+        // to use select() with a timeout.
+        -1 if os::errno() as int == INPROGRESS as int ||
+              os::errno() as int == WOULDBLOCK as int => {
+            let mut set: c::fd_set = unsafe { mem::zeroed() };
+            c::fd_set(&mut set, fd);
+            match await(fd, &mut set, timeout_ms) {
+                0 => Err(timeout("connection timed out")),
+                -1 => Err(last_net_error()),
+                _ => {
+                    let err: libc::c_int = try!(
+                        getsockopt(fd, libc::SOL_SOCKET, libc::SO_ERROR));
+                    if err == 0 {
+                        Ok(())
+                    } else {
+                        Err(decode_error_detailed(err))
+                    }
+                }
+            }
+        }
+
+        -1 => Err(last_net_error()),
+        _ => Ok(()),
+    };
+
+    // be sure to turn blocking I/O back on
+    try!(set_nonblocking(fd, false));
+    return ret;
+
+    #[cfg(unix)]
+    fn await(fd: sock_t, set: &mut c::fd_set, timeout: u64) -> libc::c_int {
+        let start = timer::now();
+        retry(|| unsafe {
+            // Recalculate the timeout each iteration (it is generally
+            // undefined what the value of the 'tv' is after select
+            // returns EINTR).
+            let mut tv = ms_to_timeval(timeout - (timer::now() - start));
+            c::select(fd + 1, ptr::null_mut(), set as *mut _,
+                      ptr::null_mut(), &mut tv)
+        })
+    }
+    #[cfg(windows)]
+    fn await(_fd: sock_t, set: &mut c::fd_set, timeout: u64) -> libc::c_int {
+        let mut tv = ms_to_timeval(timeout);
+        unsafe { c::select(1, ptr::null_mut(), set, ptr::null_mut(), &mut tv) }
+    }
+}
+
+pub fn await(fds: &[sock_t], deadline: Option<u64>,
+             status: SocketStatus) -> IoResult<()> {
+    let mut set: c::fd_set = unsafe { mem::zeroed() };
+    let mut max = 0;
+    for &fd in fds.iter() {
+        c::fd_set(&mut set, fd);
+        max = cmp::max(max, fd + 1);
+    }
+    if cfg!(windows) {
+        max = fds.len() as sock_t;
+    }
+
+    let (read, write) = match status {
+        Readable => (&mut set as *mut _, ptr::null_mut()),
+        Writable => (ptr::null_mut(), &mut set as *mut _),
+    };
+    let mut tv: libc::timeval = unsafe { mem::zeroed() };
+
+    match retry(|| {
+        let now = timer::now();
+        let tvp = match deadline {
+            None => ptr::null_mut(),
+            Some(deadline) => {
+                // If we're past the deadline, then pass a 0 timeout to
+                // select() so we can poll the status
+                let ms = if deadline < now {0} else {deadline - now};
+                tv = ms_to_timeval(ms);
+                &mut tv as *mut _
+            }
+        };
+        let r = unsafe {
+            c::select(max as libc::c_int, read, write, ptr::null_mut(), tvp)
+        };
+        r
+    }) {
+        -1 => Err(last_net_error()),
+        0 => Err(timeout("timed out")),
+        _ => Ok(()),
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Basic socket representation
+////////////////////////////////////////////////////////////////////////////////
+
+struct Inner {
+    fd: sock_t,
+
+    // Unused on Linux, where this lock is not necessary.
+    #[allow(dead_code)]
+    lock: mutex::NativeMutex
+}
+
+impl Inner {
+    fn new(fd: sock_t) -> Inner {
+        Inner { fd: fd, lock: unsafe { mutex::NativeMutex::new() } }
+    }
+}
+
+impl Drop for Inner {
+    fn drop(&mut self) { unsafe { close_sock(self.fd); } }
+}
+
+pub struct Guard<'a> {
+    pub fd: sock_t,
+    pub guard: mutex::LockGuard<'a>,
+}
+
+#[unsafe_destructor]
+impl<'a> Drop for Guard<'a> {
+    fn drop(&mut self) {
+        assert!(set_nonblocking(self.fd, false).is_ok());
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// TCP streams
+////////////////////////////////////////////////////////////////////////////////
+
+pub struct TcpStream {
+    inner: Arc<Inner>,
+    read_deadline: u64,
+    write_deadline: u64,
+}
+
+impl TcpStream {
+    pub fn connect(addr: SocketAddr, timeout: Option<u64>) -> IoResult<TcpStream> {
+        sys::init_net();
+
+        let fd = try!(socket(addr, libc::SOCK_STREAM));
+        let ret = TcpStream::new(fd);
+
+        let mut storage = unsafe { mem::zeroed() };
+        let len = addr_to_sockaddr(addr, &mut storage);
+        let addrp = &storage as *const _ as *const libc::sockaddr;
+
+        match timeout {
+            Some(timeout) => {
+                try!(connect_timeout(fd, addrp, len, timeout));
+                Ok(ret)
+            },
+            None => {
+                match retry(|| unsafe { libc::connect(fd, addrp, len) }) {
+                    -1 => Err(last_error()),
+                    _ => Ok(ret),
+                }
+            }
+        }
+    }
+
+    pub fn new(fd: sock_t) -> TcpStream {
+        TcpStream {
+            inner: Arc::new(Inner::new(fd)),
+            read_deadline: 0,
+            write_deadline: 0,
+        }
+    }
+
+    pub fn fd(&self) -> sock_t { self.inner.fd }
+
+    pub fn set_nodelay(&mut self, nodelay: bool) -> IoResult<()> {
+        setsockopt(self.fd(), libc::IPPROTO_TCP, libc::TCP_NODELAY,
+                   nodelay as libc::c_int)
+    }
+
+    pub fn set_keepalive(&mut self, seconds: Option<uint>) -> IoResult<()> {
+        let ret = setsockopt(self.fd(), libc::SOL_SOCKET, libc::SO_KEEPALIVE,
+                             seconds.is_some() as libc::c_int);
+        match seconds {
+            Some(n) => ret.and_then(|()| self.set_tcp_keepalive(n)),
+            None => ret,
+        }
+    }
+
+    #[cfg(any(target_os = "macos", target_os = "ios"))]
+    fn set_tcp_keepalive(&mut self, seconds: uint) -> IoResult<()> {
+        setsockopt(self.fd(), libc::IPPROTO_TCP, libc::TCP_KEEPALIVE,
+                   seconds as libc::c_int)
+    }
+    #[cfg(any(target_os = "freebsd", target_os = "dragonfly"))]
+    fn set_tcp_keepalive(&mut self, seconds: uint) -> IoResult<()> {
+        setsockopt(self.fd(), libc::IPPROTO_TCP, libc::TCP_KEEPIDLE,
+                   seconds as libc::c_int)
+    }
+    #[cfg(not(any(target_os = "macos",
+                  target_os = "ios",
+                  target_os = "freebsd",
+                  target_os = "dragonfly")))]
+    fn set_tcp_keepalive(&mut self, _seconds: uint) -> IoResult<()> {
+        Ok(())
+    }
+
+    #[cfg(target_os = "linux")]
+    fn lock_nonblocking(&self) {}
+
+    #[cfg(not(target_os = "linux"))]
+    fn lock_nonblocking<'a>(&'a self) -> Guard<'a> {
+        let ret = Guard {
+            fd: self.fd(),
+            guard: unsafe { self.inner.lock.lock() },
+        };
+        assert!(set_nonblocking(self.fd(), true).is_ok());
+        ret
+    }
+
+    pub fn read(&mut self, buf: &mut [u8]) -> IoResult<uint> {
+        let fd = self.fd();
+        let dolock = || self.lock_nonblocking();
+        let doread = |nb| unsafe {
+            let flags = if nb {c::MSG_DONTWAIT} else {0};
+            libc::recv(fd,
+                       buf.as_mut_ptr() as *mut libc::c_void,
+                       buf.len() as wrlen,
+                       flags) as libc::c_int
+        };
+        read(fd, self.read_deadline, dolock, doread)
+    }
+
+    pub fn write(&mut self, buf: &[u8]) -> IoResult<()> {
+        let fd = self.fd();
+        let dolock = || self.lock_nonblocking();
+        let dowrite = |nb: bool, buf: *const u8, len: uint| unsafe {
+            let flags = if nb {c::MSG_DONTWAIT} else {0};
+            libc::send(fd,
+                       buf as *const _,
+                       len as wrlen,
+                       flags) as i64
+        };
+        write(fd, self.write_deadline, buf, true, dolock, dowrite).map(|_| ())
+    }
+    pub fn peer_name(&mut self) -> IoResult<SocketAddr> {
+        sockname(self.fd(), libc::getpeername)
+    }
+
+    pub fn close_write(&mut self) -> IoResult<()> {
+        super::mkerr_libc(unsafe { libc::shutdown(self.fd(), libc::SHUT_WR) })
+    }
+    pub fn close_read(&mut self) -> IoResult<()> {
+        super::mkerr_libc(unsafe { libc::shutdown(self.fd(), libc::SHUT_RD) })
+    }
+
+    pub fn set_timeout(&mut self, timeout: Option<u64>) {
+        let deadline = timeout.map(|a| timer::now() + a).unwrap_or(0);
+        self.read_deadline = deadline;
+        self.write_deadline = deadline;
+    }
+    pub fn set_read_timeout(&mut self, timeout: Option<u64>) {
+        self.read_deadline = timeout.map(|a| timer::now() + a).unwrap_or(0);
+    }
+    pub fn set_write_timeout(&mut self, timeout: Option<u64>) {
+        self.write_deadline = timeout.map(|a| timer::now() + a).unwrap_or(0);
+    }
+
+    pub fn socket_name(&mut self) -> IoResult<SocketAddr> {
+        sockname(self.fd(), libc::getsockname)
+    }
+}
+
+impl Clone for TcpStream {
+    fn clone(&self) -> TcpStream {
+        TcpStream {
+            inner: self.inner.clone(),
+            read_deadline: 0,
+            write_deadline: 0,
+        }
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// UDP
+////////////////////////////////////////////////////////////////////////////////
+
+pub struct UdpSocket {
+    inner: Arc<Inner>,
+    read_deadline: u64,
+    write_deadline: u64,
+}
+
+impl UdpSocket {
+    pub fn bind(addr: SocketAddr) -> IoResult<UdpSocket> {
+        sys::init_net();
+
+        let fd = try!(socket(addr, libc::SOCK_DGRAM));
+        let ret = UdpSocket {
+            inner: Arc::new(Inner::new(fd)),
+            read_deadline: 0,
+            write_deadline: 0,
+        };
+
+        let mut storage = unsafe { mem::zeroed() };
+        let len = addr_to_sockaddr(addr, &mut storage);
+        let addrp = &storage as *const _ as *const libc::sockaddr;
+
+        match unsafe { libc::bind(fd, addrp, len) } {
+            -1 => Err(last_error()),
+            _ => Ok(ret),
+        }
+    }
+
+    pub fn fd(&self) -> sock_t { self.inner.fd }
+
+    pub fn set_broadcast(&mut self, on: bool) -> IoResult<()> {
+        setsockopt(self.fd(), libc::SOL_SOCKET, libc::SO_BROADCAST,
+                   on as libc::c_int)
+    }
+
+    pub fn set_multicast_loop(&mut self, on: bool) -> IoResult<()> {
+        setsockopt(self.fd(), libc::IPPROTO_IP, libc::IP_MULTICAST_LOOP,
+                   on as libc::c_int)
+    }
+
+    pub fn set_membership(&mut self, addr: IpAddr, opt: libc::c_int) -> IoResult<()> {
+        match ip_to_inaddr(addr) {
+            In4Addr(addr) => {
+                let mreq = libc::ip_mreq {
+                    imr_multiaddr: addr,
+                    // interface == INADDR_ANY
+                    imr_interface: libc::in_addr { s_addr: 0x0 },
+                };
+                setsockopt(self.fd(), libc::IPPROTO_IP, opt, mreq)
+            }
+            In6Addr(addr) => {
+                let mreq = libc::ip6_mreq {
+                    ipv6mr_multiaddr: addr,
+                    ipv6mr_interface: 0,
+                };
+                setsockopt(self.fd(), libc::IPPROTO_IPV6, opt, mreq)
+            }
+        }
+    }
+
+    #[cfg(target_os = "linux")]
+    fn lock_nonblocking(&self) {}
+
+    #[cfg(not(target_os = "linux"))]
+    fn lock_nonblocking<'a>(&'a self) -> Guard<'a> {
+        let ret = Guard {
+            fd: self.fd(),
+            guard: unsafe { self.inner.lock.lock() },
+        };
+        assert!(set_nonblocking(self.fd(), true).is_ok());
+        ret
+    }
+
+    pub fn socket_name(&mut self) -> IoResult<SocketAddr> {
+        sockname(self.fd(), libc::getsockname)
+    }
+
+    pub fn recv_from(&mut self, buf: &mut [u8]) -> IoResult<(uint, SocketAddr)> {
+        let fd = self.fd();
+        let mut storage: libc::sockaddr_storage = unsafe { mem::zeroed() };
+        let storagep = &mut storage as *mut _ as *mut libc::sockaddr;
+        let mut addrlen: libc::socklen_t =
+                mem::size_of::<libc::sockaddr_storage>() as libc::socklen_t;
+
+        let dolock = || self.lock_nonblocking();
+        let n = try!(read(fd, self.read_deadline, dolock, |nb| unsafe {
+            let flags = if nb {c::MSG_DONTWAIT} else {0};
+            libc::recvfrom(fd,
+                           buf.as_mut_ptr() as *mut libc::c_void,
+                           buf.len() as msglen_t,
+                           flags,
+                           storagep,
+                           &mut addrlen) as libc::c_int
+        }));
+        sockaddr_to_addr(&storage, addrlen as uint).and_then(|addr| {
+            Ok((n as uint, addr))
+        })
+    }
+
+    pub fn send_to(&mut self, buf: &[u8], dst: SocketAddr) -> IoResult<()> {
+        let mut storage = unsafe { mem::zeroed() };
+        let dstlen = addr_to_sockaddr(dst, &mut storage);
+        let dstp = &storage as *const _ as *const libc::sockaddr;
+
+        let fd = self.fd();
+        let dolock = || self.lock_nonblocking();
+        let dowrite = |nb, buf: *const u8, len: uint| unsafe {
+            let flags = if nb {c::MSG_DONTWAIT} else {0};
+            libc::sendto(fd,
+                         buf as *const libc::c_void,
+                         len as msglen_t,
+                         flags,
+                         dstp,
+                         dstlen) as i64
+        };
+
+        let n = try!(write(fd, self.write_deadline, buf, false, dolock, dowrite));
+        if n != buf.len() {
+            Err(short_write(n, "couldn't send entire packet at once"))
+        } else {
+            Ok(())
+        }
+    }
+
+    pub fn join_multicast(&mut self, multi: IpAddr) -> IoResult<()> {
+        match multi {
+            Ipv4Addr(..) => {
+                self.set_membership(multi, libc::IP_ADD_MEMBERSHIP)
+            }
+            Ipv6Addr(..) => {
+                self.set_membership(multi, libc::IPV6_ADD_MEMBERSHIP)
+            }
+        }
+    }
+    pub fn leave_multicast(&mut self, multi: IpAddr) -> IoResult<()> {
+        match multi {
+            Ipv4Addr(..) => {
+                self.set_membership(multi, libc::IP_DROP_MEMBERSHIP)
+            }
+            Ipv6Addr(..) => {
+                self.set_membership(multi, libc::IPV6_DROP_MEMBERSHIP)
+            }
+        }
+    }
+
+    pub fn multicast_time_to_live(&mut self, ttl: int) -> IoResult<()> {
+        setsockopt(self.fd(), libc::IPPROTO_IP, libc::IP_MULTICAST_TTL,
+                   ttl as libc::c_int)
+    }
+    pub fn time_to_live(&mut self, ttl: int) -> IoResult<()> {
+        setsockopt(self.fd(), libc::IPPROTO_IP, libc::IP_TTL, ttl as libc::c_int)
+    }
+
+    pub fn set_timeout(&mut self, timeout: Option<u64>) {
+        let deadline = timeout.map(|a| timer::now() + a).unwrap_or(0);
+        self.read_deadline = deadline;
+        self.write_deadline = deadline;
+    }
+    pub fn set_read_timeout(&mut self, timeout: Option<u64>) {
+        self.read_deadline = timeout.map(|a| timer::now() + a).unwrap_or(0);
+    }
+    pub fn set_write_timeout(&mut self, timeout: Option<u64>) {
+        self.write_deadline = timeout.map(|a| timer::now() + a).unwrap_or(0);
+    }
+}
+
+impl Clone for UdpSocket {
+    fn clone(&self) -> UdpSocket {
+        UdpSocket {
+            inner: self.inner.clone(),
+            read_deadline: 0,
+            write_deadline: 0,
+        }
+    }
+}