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Diffstat (limited to 'ctr-std/src/sys/unix/net.rs')
| -rw-r--r-- | ctr-std/src/sys/unix/net.rs | 418 |
1 files changed, 418 insertions, 0 deletions
diff --git a/ctr-std/src/sys/unix/net.rs b/ctr-std/src/sys/unix/net.rs new file mode 100644 index 0000000..b9b1a39 --- /dev/null +++ b/ctr-std/src/sys/unix/net.rs @@ -0,0 +1,418 @@ +// Copyright 2015 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. + +#![allow(dead_code)] + +use ffi::CStr; +use io; +use libc::{self, c_int, c_void, size_t, sockaddr, socklen_t, EAI_NONAME as EAI_SYSTEM, MSG_PEEK}; +use mem; +use net::{SocketAddr, Shutdown}; +use str; +use sys::fd::FileDesc; +use sys_common::{AsInner, FromInner, IntoInner}; +use sys_common::net::{getsockopt, setsockopt, sockaddr_to_addr}; +use time::{Duration, Instant}; +use cmp; + +pub use sys::{cvt, cvt_r}; +pub extern crate libc as netc; + +#[allow(non_camel_case_types)] +pub type wrlen_t = size_t; + +// See below for the usage of SOCK_CLOEXEC, but this constant is only defined on +// Linux currently (e.g. support doesn't exist on other platforms). In order to +// get name resolution to work and things to compile we just define a dummy +// SOCK_CLOEXEC here for other platforms. Note that the dummy constant isn't +// actually ever used (the blocks below are wrapped in `if cfg!` as well. +#[cfg(target_os = "linux")] +use libc::SOCK_CLOEXEC; +#[cfg(not(target_os = "linux"))] +const SOCK_CLOEXEC: c_int = 0; + +// Another conditional contant for name resolution: Macos et iOS use +// SO_NOSIGPIPE as a setsockopt flag to disable SIGPIPE emission on socket. +// Other platforms do otherwise. +#[cfg(target_vendor = "apple")] +use libc::SO_NOSIGPIPE; +#[cfg(not(target_vendor = "apple"))] +const SO_NOSIGPIPE: c_int = 0; + +pub struct Socket(FileDesc); + +pub fn init() {} + +pub fn cvt_gai(err: c_int) -> io::Result<()> { + if err == 0 { + return Ok(()) + } + if err == EAI_SYSTEM { + return Err(io::Error::last_os_error()) + } + + let detail = unsafe { + str::from_utf8(CStr::from_ptr(libc::gai_strerror(err)).to_bytes()).unwrap() + .to_owned() + }; + Err(io::Error::new(io::ErrorKind::Other, + &format!("failed to lookup address information: {}", + detail)[..])) +} + +impl Socket { + pub fn new(addr: &SocketAddr, ty: c_int) -> io::Result<Socket> { + let fam = match *addr { + SocketAddr::V4(..) => libc::AF_INET, + SocketAddr::V6(..) => libc::AF_INET6, + }; + Socket::new_raw(fam, ty) + } + + pub fn new_raw(fam: c_int, ty: c_int) -> io::Result<Socket> { + unsafe { + // On linux we first attempt to pass the SOCK_CLOEXEC flag to + // atomically create the socket and set it as CLOEXEC. Support for + // this option, however, was added in 2.6.27, and we still support + // 2.6.18 as a kernel, so if the returned error is EINVAL we + // fallthrough to the fallback. + if cfg!(target_os = "linux") { + match cvt(libc::socket(fam, ty | SOCK_CLOEXEC, 0)) { + Ok(fd) => return Ok(Socket(FileDesc::new(fd))), + Err(ref e) if e.raw_os_error() == Some(libc::EINVAL) => {} + Err(e) => return Err(e), + } + } + + let fd = cvt(libc::socket(fam, ty, 0))?; + let fd = FileDesc::new(fd); + fd.set_cloexec()?; + let socket = Socket(fd); + if cfg!(target_vendor = "apple") { + setsockopt(&socket, libc::SOL_SOCKET, SO_NOSIGPIPE, 1)?; + } + Ok(socket) + } + } + + pub fn new_pair(fam: c_int, ty: c_int) -> io::Result<(Socket, Socket)> { + unsafe { + let mut fds = [0, 0]; + + // Like above, see if we can set cloexec atomically + if cfg!(target_os = "linux") { + match cvt(libc::socketpair(fam, ty | SOCK_CLOEXEC, 0, fds.as_mut_ptr())) { + Ok(_) => { + return Ok((Socket(FileDesc::new(fds[0])), Socket(FileDesc::new(fds[1])))); + } + Err(ref e) if e.raw_os_error() == Some(libc::EINVAL) => {}, + Err(e) => return Err(e), + } + } + + cvt(libc::socketpair(fam, ty, 0, fds.as_mut_ptr()))?; + let a = FileDesc::new(fds[0]); + let b = FileDesc::new(fds[1]); + a.set_cloexec()?; + b.set_cloexec()?; + Ok((Socket(a), Socket(b))) + } + } + + pub fn connect_timeout(&self, addr: &SocketAddr, timeout: Duration) -> io::Result<()> { + self.set_nonblocking(true)?; + let r = unsafe { + let (addrp, len) = addr.into_inner(); + cvt(libc::connect(self.0.raw(), addrp, len)) + }; + self.set_nonblocking(false)?; + + match r { + Ok(_) => return Ok(()), + // there's no ErrorKind for EINPROGRESS :( + Err(ref e) if e.raw_os_error() == Some(libc::EINPROGRESS) => {} + Err(e) => return Err(e), + } + + let mut pollfd = libc::pollfd { + fd: self.0.raw(), + events: libc::POLLOUT, + revents: 0, + }; + + if timeout.as_secs() == 0 && timeout.subsec_nanos() == 0 { + return Err(io::Error::new(io::ErrorKind::InvalidInput, + "cannot set a 0 duration timeout")); + } + + let start = Instant::now(); + + loop { + let elapsed = start.elapsed(); + if elapsed >= timeout { + return Err(io::Error::new(io::ErrorKind::TimedOut, "connection timed out")); + } + + let timeout = timeout - elapsed; + let mut timeout = timeout.as_secs() + .saturating_mul(1_000) + .saturating_add(timeout.subsec_nanos() as u64 / 1_000_000); + if timeout == 0 { + timeout = 1; + } + + let timeout = cmp::min(timeout, c_int::max_value() as u64) as c_int; + + match unsafe { libc::poll(&mut pollfd, 1, timeout) } { + -1 => { + let err = io::Error::last_os_error(); + if err.kind() != io::ErrorKind::Interrupted { + return Err(err); + } + } + 0 => {} + _ => { + // linux returns POLLOUT|POLLERR|POLLHUP for refused connections (!), so look + // for POLLHUP rather than read readiness + if pollfd.revents & libc::POLLHUP != 0 { + let e = self.take_error()? + .unwrap_or_else(|| { + io::Error::new(io::ErrorKind::Other, "no error set after POLLHUP") + }); + return Err(e); + } + + return Ok(()); + } + } + } + } + + pub fn accept(&self, storage: *mut sockaddr, len: *mut socklen_t) + -> io::Result<Socket> { + let fd = cvt_r(|| unsafe { + libc::accept(self.0.raw(), storage, len) + })?; + let fd = FileDesc::new(fd); + fd.set_cloexec()?; + Ok(Socket(fd)) + } + + pub fn duplicate(&self) -> io::Result<Socket> { + self.0.duplicate().map(Socket) + } + + fn recv_with_flags(&self, buf: &mut [u8], flags: c_int) -> io::Result<usize> { + let ret = cvt(unsafe { + libc::recv(self.0.raw(), + buf.as_mut_ptr() as *mut c_void, + buf.len(), + flags) + })?; + Ok(ret as usize) + } + + pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> { + self.recv_with_flags(buf, 0) + } + + pub fn peek(&self, buf: &mut [u8]) -> io::Result<usize> { + self.recv_with_flags(buf, MSG_PEEK) + } + + fn recv_from_with_flags(&self, buf: &mut [u8], flags: c_int) + -> io::Result<(usize, SocketAddr)> { + let mut storage: libc::sockaddr_storage = unsafe { mem::zeroed() }; + let mut addrlen = mem::size_of_val(&storage) as libc::socklen_t; + + let n = cvt(unsafe { + libc::recvfrom(self.0.raw(), + buf.as_mut_ptr() as *mut c_void, + buf.len(), + flags, + &mut storage as *mut _ as *mut _, + &mut addrlen) + })?; + Ok((n as usize, sockaddr_to_addr(&storage, addrlen as usize)?)) + } + + pub fn recv_from(&self, buf: &mut [u8]) -> io::Result<(usize, SocketAddr)> { + self.recv_from_with_flags(buf, 0) + } + + pub fn peek_from(&self, buf: &mut [u8]) -> io::Result<(usize, SocketAddr)> { + self.recv_from_with_flags(buf, MSG_PEEK) + } + + pub fn write(&self, buf: &[u8]) -> io::Result<usize> { + self.0.write(buf) + } + + pub fn set_timeout(&self, dur: Option<Duration>, kind: libc::c_int) -> io::Result<()> { + let timeout = match dur { + Some(dur) => { + if dur.as_secs() == 0 && dur.subsec_nanos() == 0 { + return Err(io::Error::new(io::ErrorKind::InvalidInput, + "cannot set a 0 duration timeout")); + } + + let secs = if dur.as_secs() > libc::time_t::max_value() as u64 { + libc::time_t::max_value() + } else { + dur.as_secs() as libc::time_t + }; + let mut timeout = libc::timeval { + tv_sec: secs, + tv_usec: (dur.subsec_nanos() / 1000) as libc::suseconds_t, + }; + if timeout.tv_sec == 0 && timeout.tv_usec == 0 { + timeout.tv_usec = 1; + } + timeout + } + None => { + libc::timeval { + tv_sec: 0, + tv_usec: 0, + } + } + }; + setsockopt(self, libc::SOL_SOCKET, kind, timeout) + } + + pub fn timeout(&self, kind: libc::c_int) -> io::Result<Option<Duration>> { + let raw: libc::timeval = getsockopt(self, libc::SOL_SOCKET, kind)?; + if raw.tv_sec == 0 && raw.tv_usec == 0 { + Ok(None) + } else { + let sec = raw.tv_sec as u64; + let nsec = (raw.tv_usec as u32) * 1000; + Ok(Some(Duration::new(sec, nsec))) + } + } + + pub fn shutdown(&self, how: Shutdown) -> io::Result<()> { + let how = match how { + Shutdown::Write => libc::SHUT_WR, + Shutdown::Read => libc::SHUT_RD, + Shutdown::Both => libc::SHUT_RDWR, + }; + cvt(unsafe { libc::shutdown(self.0.raw(), how) })?; + Ok(()) + } + + pub fn set_nodelay(&self, nodelay: bool) -> io::Result<()> { + setsockopt(self, libc::IPPROTO_TCP, libc::TCP_NODELAY, nodelay as c_int) + } + + pub fn nodelay(&self) -> io::Result<bool> { + let raw: c_int = getsockopt(self, libc::IPPROTO_TCP, libc::TCP_NODELAY)?; + Ok(raw != 0) + } + + // TODO: Fix libc::FIONBIO and remove explicit cast + pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> { + let mut nonblocking = nonblocking as libc::c_int; + cvt(unsafe { libc::ioctl(*self.as_inner(), libc::FIONBIO as u32, &mut nonblocking) }).map(|_| ()) + } + + pub fn take_error(&self) -> io::Result<Option<io::Error>> { + let raw: c_int = getsockopt(self, libc::SOL_SOCKET, libc::SO_ERROR)?; + if raw == 0 { + Ok(None) + } else { + Ok(Some(io::Error::from_raw_os_error(raw as i32))) + } + } +} + +impl AsInner<c_int> for Socket { + fn as_inner(&self) -> &c_int { self.0.as_inner() } +} + +impl FromInner<c_int> for Socket { + fn from_inner(fd: c_int) -> Socket { Socket(FileDesc::new(fd)) } +} + +impl IntoInner<c_int> for Socket { + fn into_inner(self) -> c_int { self.0.into_raw() } +} + +// In versions of glibc prior to 2.26, there's a bug where the DNS resolver +// will cache the contents of /etc/resolv.conf, so changes to that file on disk +// can be ignored by a long-running program. That can break DNS lookups on e.g. +// laptops where the network comes and goes. See +// https://sourceware.org/bugzilla/show_bug.cgi?id=984. Note however that some +// distros including Debian have patched glibc to fix this for a long time. +// +// A workaround for this bug is to call the res_init libc function, to clear +// the cached configs. Unfortunately, while we believe glibc's implementation +// of res_init is thread-safe, we know that other implementations are not +// (https://github.com/rust-lang/rust/issues/43592). Code here in libstd could +// try to synchronize its res_init calls with a Mutex, but that wouldn't +// protect programs that call into libc in other ways. So instead of calling +// res_init unconditionally, we call it only when we detect we're linking +// against glibc version < 2.26. (That is, when we both know its needed and +// believe it's thread-safe). +pub fn res_init_if_glibc_before_2_26() -> io::Result<()> { + // If the version fails to parse, we treat it the same as "not glibc". + if let Some(Ok(version_str)) = glibc_version_cstr().map(CStr::to_str) { + if let Some(version) = parse_glibc_version(version_str) { + if version < (2, 26) { + let ret = unsafe { libc::res_init() }; + if ret != 0 { + return Err(io::Error::last_os_error()); + } + } + } + } + Ok(()) +} + +fn glibc_version_cstr() -> Option<&'static CStr> { + None +} + +// Returns Some((major, minor)) if the string is a valid "x.y" version, +// ignoring any extra dot-separated parts. Otherwise return None. +fn parse_glibc_version(version: &str) -> Option<(usize, usize)> { + let mut parsed_ints = version.split(".").map(str::parse::<usize>).fuse(); + match (parsed_ints.next(), parsed_ints.next()) { + (Some(Ok(major)), Some(Ok(minor))) => Some((major, minor)), + _ => None + } +} + +#[cfg(test)] +mod test { + use super::*; + + #[test] + fn test_res_init() { + // This mostly just tests that the weak linkage doesn't panic wildly... + res_init_if_glibc_before_2_26().unwrap(); + } + + #[test] + fn test_parse_glibc_version() { + let cases = [ + ("0.0", Some((0, 0))), + ("01.+2", Some((1, 2))), + ("3.4.5.six", Some((3, 4))), + ("1", None), + ("1.-2", None), + ("1.foo", None), + ("foo.1", None), + ]; + for &(version_str, parsed) in cases.iter() { + assert_eq!(parsed, parse_glibc_version(version_str)); + } + } +} |