1 files changed, 88 insertions, 16 deletions

diff --git a/ctr-std/src/sys/unix/fd.rs b/ctr-std/src/sys/unix/fd.rs
index 91adac1..e19cbb0 100644
--- a/ctr-std/src/sys/unix/fd.rs
+++ b/ctr-std/src/sys/unix/fd.rs
@@ -14,9 +14,9 @@ use cmp;
 use io::{self, Read};
 use libc::{self, c_int, c_void, ssize_t};
 use mem;
+use sync::atomic::{AtomicBool, Ordering};
 use sys::cvt;
 use sys_common::AsInner;
-use sys_common::io::read_to_end_uninitialized;
 
 #[derive(Debug)]
 pub struct FileDesc {
@@ -28,7 +28,7 @@ fn max_len() -> usize {
     // with the man page quoting that if the count of bytes to read is
     // greater than `SSIZE_MAX` the result is "unspecified".
     //
-    // On OSX, however, apparently the 64-bit libc is either buggy or
+    // On macOS, however, apparently the 64-bit libc is either buggy or
     // intentionally showing odd behavior by rejecting any read with a size
     // larger than or equal to INT_MAX. To handle both of these the read
     // size is capped on both platforms.
@@ -110,22 +110,98 @@ impl FileDesc {
         }
     }
 
-    // This is a unix-specific operation that the 3DS likely doesn't support.
-    // However, there's no reason to make calling this function an error either.
+    #[cfg(not(any(target_env = "newlib",
+                  target_os = "solaris",
+                  target_os = "emscripten",
+                  target_os = "fuchsia",
+                  target_os = "l4re",
+                  target_os = "haiku")))]
     pub fn set_cloexec(&self) -> io::Result<()> {
-        Ok(())
+        unsafe {
+            cvt(libc::ioctl(self.fd, libc::FIOCLEX))?;
+            Ok(())
+        }
+    }
+    #[cfg(any(target_env = "newlib",
+              target_os = "solaris",
+              target_os = "emscripten",
+              target_os = "fuchsia",
+              target_os = "l4re",
+              target_os = "haiku"))]
+    pub fn set_cloexec(&self) -> io::Result<()> {
+        unsafe {
+            let previous = cvt(libc::fcntl(self.fd, libc::F_GETFD))?;
+            let new = previous | libc::FD_CLOEXEC;
+            if new != previous {
+                cvt(libc::fcntl(self.fd, libc::F_SETFD, new))?;
+            }
+            Ok(())
+        }
     }
 
-    // This is a unix-specific operation that the 3DS likely doesn't support.
-    // However, there's no reason to make calling this function an error either.
-    pub fn set_nonblocking(&self) -> io::Result<()> {
-        Ok(())
+    pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
+        unsafe {
+            let previous = cvt(libc::fcntl(self.fd, libc::F_GETFL))?;
+            let new = if nonblocking {
+                previous | libc::O_NONBLOCK
+            } else {
+                previous & !libc::O_NONBLOCK
+            };
+            if new != previous {
+                cvt(libc::fcntl(self.fd, libc::F_SETFL, new))?;
+            }
+            Ok(())
+        }
     }
 
-    // The sdmc and romfs devoptabs definitely don't support this operation.
-    // Not sure if it will be needed for network support or not.
     pub fn duplicate(&self) -> io::Result<FileDesc> {
-        unimplemented!()
+        // 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.
+        //
+        // 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(any(target_os = "android", target_os = "haiku"))]
+        use libc::F_DUPFD as F_DUPFD_CLOEXEC;
+        #[cfg(not(any(target_os = "android", target_os="haiku")))]
+        use libc::F_DUPFD_CLOEXEC;
+
+        let make_filedesc = |fd| {
+            let fd = FileDesc::new(fd);
+            fd.set_cloexec()?;
+            Ok(fd)
+        };
+        static TRY_CLOEXEC: AtomicBool =
+            AtomicBool::new(!cfg!(target_os = "android"));
+        let fd = self.raw();
+        if TRY_CLOEXEC.load(Ordering::Relaxed) {
+            match cvt(unsafe { libc::fcntl(fd, F_DUPFD_CLOEXEC, 0) }) {
+                // We *still* call the `set_cloexec` method as apparently some
+                // linux kernel at some point stopped setting CLOEXEC even
+                // though it reported doing so on F_DUPFD_CLOEXEC.
+                Ok(fd) => {
+                    return Ok(if cfg!(target_os = "linux") {
+                        make_filedesc(fd)?
+                    } else {
+                        FileDesc::new(fd)
+                    })
+                }
+                Err(ref e) if e.raw_os_error() == Some(libc::EINVAL) => {
+                    TRY_CLOEXEC.store(false, Ordering::Relaxed);
+                }
+                Err(e) => return Err(e),
+            }
+        }
+        cvt(unsafe { libc::fcntl(fd, libc::F_DUPFD, 0) }).and_then(make_filedesc)
     }
 }
 
@@ -133,10 +209,6 @@ impl<'a> Read for &'a FileDesc {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         (**self).read(buf)
     }
-
-    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
-        unsafe { read_to_end_uninitialized(self, buf) }
-    }
 }
 
 impl AsInner<c_int> for FileDesc {