1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![unstable(reason = "not public", issue = "0", feature = "fd")]
14 use libc::{self, c_int, c_void};
16 use sync::atomic::{AtomicBool, Ordering};
18 use sys_common::AsInner;
19 use sys_common::io::read_to_end_uninitialized;
26 pub fn new(fd: c_int) -> FileDesc {
30 pub fn raw(&self) -> c_int { self.fd }
32 /// Extracts the actual filedescriptor without closing it.
33 pub fn into_raw(self) -> c_int {
39 pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
40 let ret = cvt(unsafe {
42 buf.as_mut_ptr() as *mut c_void,
48 pub fn read_to_end(&self, buf: &mut Vec<u8>) -> io::Result<usize> {
50 (&mut me).read_to_end(buf)
53 pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
54 let ret = cvt(unsafe {
56 buf.as_ptr() as *const c_void,
62 #[cfg(not(any(target_env = "newlib",
63 target_os = "solaris",
64 target_os = "emscripten",
65 target_os = "haiku")))]
66 pub fn set_cloexec(&self) -> io::Result<()> {
68 cvt(libc::ioctl(self.fd, libc::FIOCLEX))?;
72 #[cfg(any(target_env = "newlib",
73 target_os = "solaris",
74 target_os = "emscripten",
75 target_os = "haiku"))]
76 pub fn set_cloexec(&self) -> io::Result<()> {
78 let previous = cvt(libc::fcntl(self.fd, libc::F_GETFD))?;
79 cvt(libc::fcntl(self.fd, libc::F_SETFD, previous | libc::FD_CLOEXEC))?;
84 pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
86 let previous = cvt(libc::fcntl(self.fd, libc::F_GETFL))?;
87 let new = if nonblocking {
88 previous | libc::O_NONBLOCK
90 previous & !libc::O_NONBLOCK
92 cvt(libc::fcntl(self.fd, libc::F_SETFL, new))?;
97 pub fn duplicate(&self) -> io::Result<FileDesc> {
98 // We want to atomically duplicate this file descriptor and set the
99 // CLOEXEC flag, and currently that's done via F_DUPFD_CLOEXEC. This
100 // flag, however, isn't supported on older Linux kernels (earlier than
103 // To detect this and ensure that CLOEXEC is still set, we
104 // follow a strategy similar to musl [1] where if passing
105 // F_DUPFD_CLOEXEC causes `fcntl` to return EINVAL it means it's not
106 // supported (the third parameter, 0, is always valid), so we stop
109 // Also note that Android doesn't have F_DUPFD_CLOEXEC, but get it to
110 // resolve so we at least compile this.
112 // [1]: http://comments.gmane.org/gmane.linux.lib.musl.general/2963
113 #[cfg(any(target_os = "android", target_os = "haiku"))]
114 use libc::F_DUPFD as F_DUPFD_CLOEXEC;
115 #[cfg(not(any(target_os = "android", target_os="haiku")))]
116 use libc::F_DUPFD_CLOEXEC;
118 let make_filedesc = |fd| {
119 let fd = FileDesc::new(fd);
123 static TRY_CLOEXEC: AtomicBool =
124 AtomicBool::new(!cfg!(target_os = "android"));
126 if TRY_CLOEXEC.load(Ordering::Relaxed) {
127 match cvt(unsafe { libc::fcntl(fd, F_DUPFD_CLOEXEC, 0) }) {
128 // We *still* call the `set_cloexec` method as apparently some
129 // linux kernel at some point stopped setting CLOEXEC even
130 // though it reported doing so on F_DUPFD_CLOEXEC.
132 return Ok(if cfg!(target_os = "linux") {
138 Err(ref e) if e.raw_os_error() == Some(libc::EINVAL) => {
139 TRY_CLOEXEC.store(false, Ordering::Relaxed);
141 Err(e) => return Err(e),
144 cvt(unsafe { libc::fcntl(fd, libc::F_DUPFD, 0) }).and_then(make_filedesc)
148 impl<'a> Read for &'a FileDesc {
149 fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
153 fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
154 unsafe { read_to_end_uninitialized(self, buf) }
158 impl AsInner<c_int> for FileDesc {
159 fn as_inner(&self) -> &c_int { &self.fd }
162 impl Drop for FileDesc {
164 // Note that errors are ignored when closing a file descriptor. The
165 // reason for this is that if an error occurs we don't actually know if
166 // the file descriptor was closed or not, and if we retried (for
167 // something like EINTR), we might close another valid file descriptor
168 // (opened after we closed ours.
169 let _ = unsafe { libc::close(self.fd) };