bjoernager/rust
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Add File::try_clone

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This commit is contained in:
Steven Fackler 2016-01-20 21:24:23 -08:00
parent 51108b64ca
commit a414b61f92
5 changed files with 87 additions and 39 deletions
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40
src/libstd/sys/unix/net.rs
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@ -15,7 +15,6 @@ use io;
use libc::{self, c_int, size_t};
use net::{SocketAddr, Shutdown};
use str;
use sync::atomic::{AtomicBool, Ordering};
use sys::fd::FileDesc;
use sys_common::{AsInner, FromInner, IntoInner};
use sys_common::net::{getsockopt, setsockopt};
@ -67,44 +66,7 @@ impl Socket {
}
pub fn duplicate(&self) -> io::Result<Socket> {
// We want to atomically duplicate this file descriptor and set the
// CLOEXEC flag, and currently that's done via F_DUPFD_CLOEXEC. This
// flag, however, isn't supported on older Linux kernels (earlier than
// 2.6.24).
//
// To detect this and ensure that CLOEXEC is still set, we
// follow a strategy similar to musl [1] where if passing
// F_DUPFD_CLOEXEC causes `fcntl` to return EINVAL it means it's not
// supported (the third parameter, 0, is always valid), so we stop
// trying that. We also *still* call the `set_cloexec` method as
// apparently some kernel at some point stopped setting CLOEXEC even
// though it reported doing so on F_DUPFD_CLOEXEC.
//
// Also note that Android doesn't have F_DUPFD_CLOEXEC, but get it to
// resolve so we at least compile this.
//
// [1]: http://comments.gmane.org/gmane.linux.lib.musl.general/2963
#[cfg(target_os = "android")]
use libc::F_DUPFD as F_DUPFD_CLOEXEC;
#[cfg(not(target_os = "android"))]
use libc::F_DUPFD_CLOEXEC;
let make_socket = |fd| {
let fd = FileDesc::new(fd);
fd.set_cloexec();
Socket(fd)
};
static TRY_CLOEXEC: AtomicBool = AtomicBool::new(true);
let fd = self.0.raw();
if !cfg!(target_os = "android") && TRY_CLOEXEC.load(Ordering::Relaxed) {
match cvt(unsafe { libc::fcntl(fd, F_DUPFD_CLOEXEC, 0) }) {
Err(ref e) if e.raw_os_error() == Some(libc::EINVAL) => {
TRY_CLOEXEC.store(false, Ordering::Relaxed);
}
res => return res.map(make_socket),
}
}
cvt(unsafe { libc::fcntl(fd, libc::F_DUPFD, 0) }).map(make_socket)
self.0.duplicate().map(Socket)
}
pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {