openat variant

1 files changed, 696 insertions, 0 deletions

diff --git a/openat/src/dir.rs b/openat/src/dir.rs
new file mode 100644
index 0000000..eac2f38
--- /dev/null
+++ b/openat/src/dir.rs
@@ -0,0 +1,696 @@
+use std::io;
+use std::mem;
+use std::ffi::{OsString, CStr};
+use std::fs::{File, read_link};
+use std::os::unix::io::{AsRawFd, RawFd, FromRawFd, IntoRawFd};
+use std::os::unix::ffi::{OsStringExt};
+use std::path::{PathBuf};
+
+use libc;
+use crate::metadata::{self, Metadata};
+use crate::list::{DirIter, open_dir, open_dirfd};
+
+use crate::{Dir, AsPath};
+
+#[cfg(target_os="linux")]
+const BASE_OPEN_FLAGS: libc::c_int = libc::O_PATH|libc::O_CLOEXEC;
+#[cfg(target_os="freebsd")]
+const BASE_OPEN_FLAGS: libc::c_int = libc::O_DIRECTORY|libc::O_CLOEXEC;
+#[cfg(not(any(target_os="linux", target_os="freebsd")))]
+const BASE_OPEN_FLAGS: libc::c_int = libc::O_CLOEXEC;
+
+impl Dir {
+    /// Creates a directory descriptor that resolves paths relative to current
+    /// working directory (AT_FDCWD)
+    #[deprecated(since="0.1.15", note="\
+        Use `Dir::open(\".\")` instead. \
+        Dir::cwd() doesn't open actual file descriptor and uses magic value \
+        instead which resolves to current dir on any syscall invocation. \
+        This is usually counter-intuitive and yields a broken \
+        file descriptor when using `Dir::as_raw_fd`. \
+        Will be removed in version v0.2 of the library.")]
+    pub fn cwd() -> Dir {
+        Dir(libc::AT_FDCWD)
+    }
+
+    /// Open a directory descriptor at specified path
+    // TODO(tailhook) maybe accept only absolute paths?
+    pub fn open<P: AsPath>(path: P) -> io::Result<Dir> {
+        Dir::_open(to_cstr(path)?.as_ref())
+    }
+
+    fn _open(path: &CStr) -> io::Result<Dir> {
+        let fd = unsafe {
+            libc::open(path.as_ptr(), BASE_OPEN_FLAGS)
+        };
+        if fd < 0 {
+            Err(io::Error::last_os_error())
+        } else {
+            Ok(Dir(fd))
+        }
+    }
+
+    /// List subdirectory of this dir
+    ///
+    /// You can list directory itself with `list_self`.
+    pub fn list_dir<P: AsPath>(&self, path: P) -> io::Result<DirIter> {
+        open_dir(self, to_cstr(path)?.as_ref())
+    }
+
+    /// List this dir
+    pub fn list_self(&self) -> io::Result<DirIter> {
+        unsafe {
+            open_dirfd(libc::dup(self.0))
+        }
+    }
+
+    /// Open subdirectory
+    ///
+    /// Note that this method does not resolve symlinks by default, so you may have to call
+    /// [`read_link`] to resolve the real path first.
+    ///
+    /// [`read_link`]: #method.read_link
+    pub fn sub_dir<P: AsPath>(&self, path: P) -> io::Result<Dir> {
+        self._sub_dir(to_cstr(path)?.as_ref())
+    }
+
+    fn _sub_dir(&self, path: &CStr) -> io::Result<Dir> {
+        let fd = unsafe {
+            libc::openat(self.0,
+                        path.as_ptr(),
+                        BASE_OPEN_FLAGS|libc::O_NOFOLLOW)
+        };
+        if fd < 0 {
+            Err(io::Error::last_os_error())
+        } else {
+            Ok(Dir(fd))
+        }
+    }
+
+    /// Read link in this directory
+    pub fn read_link<P: AsPath>(&self, path: P) -> io::Result<PathBuf> {
+        self._read_link(to_cstr(path)?.as_ref())
+    }
+
+    fn _read_link(&self, path: &CStr) -> io::Result<PathBuf> {
+        let mut buf = vec![0u8; 4096];
+        let res = unsafe {
+            libc::readlinkat(self.0,
+                        path.as_ptr(),
+                        buf.as_mut_ptr() as *mut libc::c_char, buf.len())
+        };
+        if res < 0 {
+            Err(io::Error::last_os_error())
+        } else {
+            buf.truncate(res as usize);
+            Ok(OsString::from_vec(buf).into())
+        }
+    }
+
+    /// Open file for reading in this directory
+    ///
+    /// Note that this method does not resolve symlinks by default, so you may have to call
+    /// [`read_link`] to resolve the real path first.
+    ///
+    /// [`read_link`]: #method.read_link
+    pub fn open_file<P: AsPath>(&self, path: P) -> io::Result<File> {
+        self._open_file(to_cstr(path)?.as_ref(),
+            libc::O_RDONLY, 0)
+    }
+
+    /// Open file with specified flags relative to this directory
+    pub fn open_file_ex<P: AsPath>(&self, path: P, flags: libc::c_int, mode: libc::mode_t) -> io::Result<File> {
+        self._open_file(to_cstr(path)?.as_ref(), flags, mode)
+    }
+
+    /// Open file for writing, create if necessary, truncate on open
+    ///
+    /// If there exists a symlink at the destination path, this method will fail. In that case, you
+    /// will need to remove the symlink before calling this method. If you are on Linux, you can
+    /// alternatively create an unnamed file with [`new_unnamed_file`] and then rename it,
+    /// clobbering the symlink at the destination.
+    ///
+    /// [`new_unnamed_file`]: #method.new_unnamed_file
+    pub fn write_file<P: AsPath>(&self, path: P, mode: libc::mode_t)
+        -> io::Result<File>
+    {
+        self._open_file(to_cstr(path)?.as_ref(),
+            libc::O_CREAT|libc::O_WRONLY|libc::O_TRUNC,
+            mode)
+    }
+
+    /// Open file for append, create if necessary
+    ///
+    /// If there exists a symlink at the destination path, this method will fail. In that case, you
+    /// will need to call [`read_link`] to resolve the real path first.
+    ///
+    /// [`read_link`]: #method.read_link
+    pub fn append_file<P: AsPath>(&self, path: P, mode: libc::mode_t)
+        -> io::Result<File>
+    {
+        self._open_file(to_cstr(path)?.as_ref(),
+            libc::O_CREAT|libc::O_WRONLY|libc::O_APPEND,
+            mode)
+    }
+
+    /// Create file for writing (and truncate) in this directory
+    ///
+    /// Deprecated alias for `write_file`
+    ///
+    /// If there exists a symlink at the destination path, this method will fail. In that case, you
+    /// will need to remove the symlink before calling this method. If you are on Linux, you can
+    /// alternatively create an unnamed file with [`new_unnamed_file`] and then rename it,
+    /// clobbering the symlink at the destination.
+    ///
+    /// [`new_unnamed_file`]: #method.new_unnamed_file
+    #[deprecated(since="0.1.7", note="please use `write_file` instead")]
+    pub fn create_file<P: AsPath>(&self, path: P, mode: libc::mode_t)
+        -> io::Result<File>
+    {
+        self._open_file(to_cstr(path)?.as_ref(),
+            libc::O_CREAT|libc::O_WRONLY|libc::O_TRUNC,
+            mode)
+    }
+
+    /// Create a tmpfile in this directory which isn't linked to any filename
+    ///
+    /// This works by passing `O_TMPFILE` into the openat call. The flag is
+    /// supported only on linux. So this function always returns error on
+    /// such systems.
+    ///
+    /// **WARNING!** On glibc < 2.22 file permissions of the newly created file
+    /// may be arbitrary. Consider chowning after creating a file.
+    ///
+    /// Note: It may be unclear why creating unnamed file requires a dir. There
+    /// are two reasons:
+    ///
+    /// 1. It's created (and occupies space) on a real filesystem, so the
+    ///    directory is a way to find out which filesystem to attach file to
+    /// 2. This method is mostly needed to initialize the file then link it
+    ///    using ``link_file_at`` to the real directory entry. When linking
+    ///    it must be linked into the same filesystem. But because for most
+    ///    programs finding out filesystem layout is an overkill the rule of
+    ///    thumb is to create a file in the the target directory.
+    ///
+    /// Currently, we recommend to fallback on any error if this operation
+    /// can't be accomplished rather than relying on specific error codes,
+    /// because semantics of errors are very ugly.
+    #[cfg(target_os="linux")]
+    pub fn new_unnamed_file(&self, mode: libc::mode_t)
+        -> io::Result<File>
+    {
+        self._open_file(unsafe { CStr::from_bytes_with_nul_unchecked(b".\0") },
+            libc::O_TMPFILE|libc::O_WRONLY,
+            mode)
+    }
+
+    /// Create a tmpfile in this directory which isn't linked to any filename
+    ///
+    /// This works by passing `O_TMPFILE` into the openat call. The flag is
+    /// supported only on linux. So this function always returns error on
+    /// such systems.
+    ///
+    /// Note: It may be unclear why creating unnamed file requires a dir. There
+    /// are two reasons:
+    ///
+    /// 1. It's created (and occupies space) on a real filesystem, so the
+    ///    directory is a way to find out which filesystem to attach file to
+    /// 2. This method is mostly needed to initialize the file then link it
+    ///    using ``link_file_at`` to the real directory entry. When linking
+    ///    it must be linked into the same filesystem. But because for most
+    ///    programs finding out filesystem layout is an overkill the rule of
+    ///    thumb is to create a file in the the target directory.
+    ///
+    /// Currently, we recommend to fallback on any error if this operation
+    /// can't be accomplished rather than relying on specific error codes,
+    /// because semantics of errors are very ugly.
+    #[cfg(not(target_os="linux"))]
+    pub fn new_unnamed_file<P: AsPath>(&self, _mode: libc::mode_t)
+        -> io::Result<File>
+    {
+        Err(io::Error::new(io::ErrorKind::Other,
+            "creating unnamed tmpfiles is only supported on linux"))
+    }
+
+    /// Link open file to a specified path
+    ///
+    /// This is used with ``new_unnamed_file()`` to create and initialize the
+    /// file before linking it into a filesystem. This requires `/proc` to be
+    /// mounted and works **only on linux**.
+    ///
+    /// On systems other than linux this always returns error. It's expected
+    /// that in most cases this methos is not called if ``new_unnamed_file``
+    /// fails. But in obscure scenarios where `/proc` is not mounted this
+    /// method may fail even on linux. So your code should be able to fallback
+    /// to a named file if this method fails too.
+    #[cfg(target_os="linux")]
+    pub fn link_file_at<F: AsRawFd, P: AsPath>(&self, file: &F, path: P)
+        -> io::Result<()>
+    {
+        let fd_path = format!("/proc/self/fd/{}", file.as_raw_fd());
+        _hardlink(&Dir(libc::AT_FDCWD), to_cstr(fd_path)?.as_ref(),
+            &self, to_cstr(path)?.as_ref(),
+            libc::AT_SYMLINK_FOLLOW)
+    }
+
+    /// Link open file to a specified path
+    ///
+    /// This is used with ``new_unnamed_file()`` to create and initialize the
+    /// file before linking it into a filesystem. This requires `/proc` to be
+    /// mounted and works **only on linux**.
+    ///
+    /// On systems other than linux this always returns error. It's expected
+    /// that in most cases this methos is not called if ``new_unnamed_file``
+    /// fails. But in obscure scenarios where `/proc` is not mounted this
+    /// method may fail even on linux. So your code should be able to fallback
+    /// to a named file if this method fails too.
+    #[cfg(not(target_os="linux"))]
+    pub fn link_file_at<F: AsRawFd, P: AsPath>(&self, _file: F, _path: P)
+        -> io::Result<()>
+    {
+        Err(io::Error::new(io::ErrorKind::Other,
+            "linking unnamed fd to directories is only supported on linux"))
+    }
+
+    /// Create file if not exists, fail if exists
+    ///
+    /// This function checks existence and creates file atomically with
+    /// respect to other threads and processes.
+    ///
+    /// Technically it means passing `O_EXCL` flag to open.
+    pub fn new_file<P: AsPath>(&self, path: P, mode: libc::mode_t)
+        -> io::Result<File>
+    {
+        self._open_file(to_cstr(path)?.as_ref(),
+            libc::O_CREAT|libc::O_EXCL|libc::O_WRONLY,
+            mode)
+    }
+
+    /// Open file for reading and writing without truncation, create if needed
+    ///
+    /// If there exists a symlink at the destination path, this method will fail. In that case, you
+    /// will need to call [`read_link`] to resolve the real path first.
+    ///
+    /// [`read_link`]: #method.read_link
+    pub fn update_file<P: AsPath>(&self, path: P, mode: libc::mode_t)
+        -> io::Result<File>
+    {
+        self._open_file(to_cstr(path)?.as_ref(),
+            libc::O_CREAT|libc::O_RDWR,
+            mode)
+    }
+
+    fn _open_file(&self, path: &CStr, flags: libc::c_int, mode: libc::mode_t)
+        -> io::Result<File>
+    {
+        unsafe {
+            // Note: In below call to `openat`, *mode* must be cast to
+            // `unsigned` because the optional `mode` argument to `openat` is
+            // variadic in the signature. Since integers are not implicitly
+            // promoted as they are in C this would break on Freebsd where
+            // *mode_t* is an alias for `uint16_t`.
+            let res = libc::openat(self.0, path.as_ptr(),
+                            flags|libc::O_CLOEXEC|libc::O_NOFOLLOW,
+                            mode as libc::c_uint);
+            if res < 0 {
+                Err(io::Error::last_os_error())
+            } else {
+                Ok(File::from_raw_fd(res))
+            }
+        }
+    }
+
+    /// Make a symlink in this directory
+    ///
+    /// Note: the order of arguments differ from `symlinkat`
+    pub fn symlink<P: AsPath, R: AsPath>(&self, path: P, value: R)
+        -> io::Result<()>
+    {
+        self._symlink(to_cstr(path)?.as_ref(), to_cstr(value)?.as_ref())
+    }
+    fn _symlink(&self, path: &CStr, link: &CStr) -> io::Result<()> {
+        unsafe {
+            let res = libc::symlinkat(link.as_ptr(),
+                self.0, path.as_ptr());
+            if res < 0 {
+                Err(io::Error::last_os_error())
+            } else {
+                Ok(())
+            }
+        }
+    }
+
+    /// Create a subdirectory in this directory
+    pub fn create_dir<P: AsPath>(&self, path: P, mode: libc::mode_t)
+        -> io::Result<()>
+    {
+        self._create_dir(to_cstr(path)?.as_ref(), mode)
+    }
+    fn _create_dir(&self, path: &CStr, mode: libc::mode_t) -> io::Result<()> {
+        unsafe {
+            let res = libc::mkdirat(self.0, path.as_ptr(), mode);
+            if res < 0 {
+                Err(io::Error::last_os_error())
+            } else {
+                Ok(())
+            }
+        }
+    }
+
+    /// Rename a file in this directory to another name (keeping same dir)
+    pub fn local_rename<P: AsPath, R: AsPath>(&self, old: P, new: R)
+        -> io::Result<()>
+    {
+        rename(self, to_cstr(old)?.as_ref(), self, to_cstr(new)?.as_ref())
+    }
+
+    /// Similar to `local_rename` but atomically swaps both paths
+    ///
+    /// Only supported on Linux.
+    #[cfg(target_os="linux")]
+    pub fn local_exchange<P: AsPath, R: AsPath>(&self, old: P, new: R)
+        -> io::Result<()>
+    {
+        // Workaround https://github.com/tailhook/openat/issues/35
+        // AKA https://github.com/rust-lang/libc/pull/2116
+        // Unfortunately since we made this libc::c_int in our
+        // public API, we can't easily change it right now.
+        let flags = libc::RENAME_EXCHANGE as libc::c_int;
+        rename_flags(self, to_cstr(old)?.as_ref(),
+            self, to_cstr(new)?.as_ref(),
+            flags)
+    }
+
+    /// Remove a subdirectory in this directory
+    ///
+    /// Note only empty directory may be removed
+    pub fn remove_dir<P: AsPath>(&self, path: P)
+        -> io::Result<()>
+    {
+        self._unlink(to_cstr(path)?.as_ref(), libc::AT_REMOVEDIR)
+    }
+    /// Remove a file in this directory
+    pub fn remove_file<P: AsPath>(&self, path: P)
+        -> io::Result<()>
+    {
+        self._unlink(to_cstr(path)?.as_ref(), 0)
+    }
+    fn _unlink(&self, path: &CStr, flags: libc::c_int) -> io::Result<()> {
+        unsafe {
+            let res = libc::unlinkat(self.0, path.as_ptr(), flags);
+            if res < 0 {
+                Err(io::Error::last_os_error())
+            } else {
+                Ok(())
+            }
+        }
+    }
+
+    /// Get the path of this directory (if possible)
+    ///
+    /// This uses symlinks in `/proc/self`, they sometimes may not be
+    /// available so use with care.
+    pub fn recover_path(&self) -> io::Result<PathBuf> {
+        let fd = self.0;
+        if fd != libc::AT_FDCWD {
+            read_link(format!("/proc/self/fd/{}", fd))
+        } else {
+            read_link("/proc/self/cwd")
+        }
+    }
+
+    /// Returns metadata of an entry in this directory
+    ///
+    /// If the destination path is a symlink, this will return the metadata of the symlink itself.
+    /// If you would like to follow the symlink and return the metadata of the target, you will
+    /// have to call [`read_link`] to resolve the real path first.
+    ///
+    /// [`read_link`]: #method.read_link
+    pub fn metadata<P: AsPath>(&self, path: P) -> io::Result<Metadata> {
+        self._stat(to_cstr(path)?.as_ref(), libc::AT_SYMLINK_NOFOLLOW)
+    }
+    fn _stat(&self, path: &CStr, flags: libc::c_int) -> io::Result<Metadata> {
+        unsafe {
+            let mut stat = mem::zeroed();
+            let res = libc::fstatat(self.0, path.as_ptr(),
+                &mut stat, flags);
+            if res < 0 {
+                Err(io::Error::last_os_error())
+            } else {
+                Ok(metadata::new(stat))
+            }
+        }
+    }
+
+    /// Returns the metadata of the directory itself.
+    pub fn self_metadata(&self) -> io::Result<Metadata> {
+        unsafe {
+            let mut stat = mem::zeroed();
+            let res = libc::fstat(self.0, &mut stat);
+            if res < 0 {
+                Err(io::Error::last_os_error())
+            } else {
+                Ok(metadata::new(stat))
+            }
+        }
+    }
+
+    /// Constructs a new `Dir` from a given raw file descriptor,
+    /// ensuring it is a directory file descriptor first.
+    ///
+    /// This function **consumes ownership** of the specified file
+    /// descriptor. The returned `Dir` will take responsibility for
+    /// closing it when it goes out of scope.
+    pub unsafe fn from_raw_fd_checked(fd: RawFd) -> io::Result<Self> {
+        let mut stat = mem::zeroed();
+        let res = libc::fstat(fd, &mut stat);
+        if res < 0 {
+            Err(io::Error::last_os_error())
+        } else {
+            match stat.st_mode & libc::S_IFMT {
+                libc::S_IFDIR => Ok(Dir(fd)),
+                _ => Err(io::Error::from_raw_os_error(libc::ENOTDIR))
+            }
+        }
+    }
+
+    /// Creates a new independently owned handle to the underlying directory.
+    pub fn try_clone(&self) -> io::Result<Self> {
+        let fd = unsafe { libc::dup(self.0) };
+        if fd == -1 {
+            Err(io::Error::last_os_error())
+        } else {
+            unsafe { Self::from_raw_fd_checked(fd) }
+        }
+    }
+}
+
+/// Rename (move) a file between directories
+///
+/// Files must be on a single filesystem anyway. This funtion does **not**
+/// fallback to copying if needed.
+pub fn rename<P, R>(old_dir: &Dir, old: P, new_dir: &Dir, new: R)
+    -> io::Result<()>
+    where P: AsPath, R: AsPath,
+{
+    _rename(old_dir, to_cstr(old)?.as_ref(), new_dir, to_cstr(new)?.as_ref())
+}
+
+fn _rename(old_dir: &Dir, old: &CStr, new_dir: &Dir, new: &CStr)
+    -> io::Result<()>
+{
+    unsafe {
+        let res = libc::renameat(old_dir.0, old.as_ptr(),
+            new_dir.0, new.as_ptr());
+        if res < 0 {
+            Err(io::Error::last_os_error())
+        } else {
+            Ok(())
+        }
+    }
+}
+
+/// Create a hardlink to a file
+///
+/// Files must be on a single filesystem even if they are in different
+/// directories.
+///
+/// Note: by default ``linkat`` syscall doesn't resolve symbolic links, and
+/// it's also behavior of this function. It's recommended to resolve symlinks
+/// manually if needed.
+pub fn hardlink<P, R>(old_dir: &Dir, old: P, new_dir: &Dir, new: R)
+    -> io::Result<()>
+    where P: AsPath, R: AsPath,
+{
+    _hardlink(old_dir, to_cstr(old)?.as_ref(),
+              new_dir, to_cstr(new)?.as_ref(),
+              0)
+}
+
+fn _hardlink(old_dir: &Dir, old: &CStr, new_dir: &Dir, new: &CStr,
+             flags: libc::c_int)
+    -> io::Result<()>
+{
+    unsafe {
+        let res = libc::linkat(old_dir.0, old.as_ptr(),
+            new_dir.0, new.as_ptr(), flags);
+        if res < 0 {
+            Err(io::Error::last_os_error())
+        } else {
+            Ok(())
+        }
+    }
+}
+
+/// Rename (move) a file between directories with flags
+///
+/// Files must be on a single filesystem anyway. This funtion does **not**
+/// fallback to copying if needed.
+///
+/// Only supported on Linux.
+#[cfg(target_os="linux")]
+pub fn rename_flags<P, R>(old_dir: &Dir, old: P, new_dir: &Dir, new: R,
+    flags: libc::c_int)
+    -> io::Result<()>
+    where P: AsPath, R: AsPath,
+{
+    _rename_flags(old_dir, to_cstr(old)?.as_ref(),
+        new_dir, to_cstr(new)?.as_ref(),
+        flags)
+}
+
+#[cfg(target_os="linux")]
+fn _rename_flags(old_dir: &Dir, old: &CStr, new_dir: &Dir, new: &CStr,
+    flags: libc::c_int)
+    -> io::Result<()>
+{
+    unsafe {
+        let res = libc::syscall(
+            libc::SYS_renameat2,
+            old_dir.0, old.as_ptr(),
+            new_dir.0, new.as_ptr(), flags);
+        if res < 0 {
+            Err(io::Error::last_os_error())
+        } else {
+            Ok(())
+        }
+    }
+}
+
+impl AsRawFd for Dir {
+    #[inline]
+    fn as_raw_fd(&self) -> RawFd {
+        self.0
+    }
+}
+
+impl FromRawFd for Dir {
+    /// The user must guarantee that the passed in `RawFd` is in fact
+    /// a directory file descriptor.
+    #[inline]
+    unsafe fn from_raw_fd(fd: RawFd) -> Dir {
+        Dir(fd)
+    }
+}
+
+impl IntoRawFd for Dir {
+    #[inline]
+    fn into_raw_fd(self) -> RawFd {
+        let result = self.0;
+        mem::forget(self);
+        return result;
+    }
+}
+
+impl Drop for Dir {
+    fn drop(&mut self) {
+        let fd = self.0;
+        if fd != libc::AT_FDCWD {
+            unsafe {
+                libc::close(fd);
+            }
+        }
+    }
+}
+
+fn to_cstr<P: AsPath>(path: P) -> io::Result<P::Buffer> {
+    path.to_path()
+    .ok_or_else(|| {
+        io::Error::new(io::ErrorKind::InvalidInput,
+                       "nul byte in file name")
+    })
+}
+
+#[cfg(test)]
+mod test {
+    use std::io::{Read};
+    use std::path::Path;
+    use std::os::unix::io::{FromRawFd, IntoRawFd};
+    use crate::{Dir};
+
+    #[test]
+    fn test_open_ok() {
+        assert!(Dir::open("src").is_ok());
+    }
+
+    #[test]
+    #[cfg_attr(target_os="freebsd", should_panic(expected="Not a directory"))]
+    fn test_open_file() {
+        Dir::open("src/lib.rs").unwrap();
+    }
+
+    #[test]
+    fn test_read_file() {
+        let dir = Dir::open("src").unwrap();
+        let mut buf = String::new();
+        dir.open_file("lib.rs").unwrap()
+            .read_to_string(&mut buf).unwrap();
+        assert!(buf.find("extern crate libc;").is_some());
+    }
+
+    #[test]
+    fn test_from_into() {
+        let dir = Dir::open("src").unwrap();
+        let dir = unsafe { Dir::from_raw_fd(dir.into_raw_fd()) };
+        let mut buf = String::new();
+        dir.open_file("lib.rs").unwrap()
+            .read_to_string(&mut buf).unwrap();
+        assert!(buf.find("extern crate libc;").is_some());
+    }
+
+    #[test]
+    #[should_panic(expected="No such file or directory")]
+    fn test_open_no_dir() {
+        Dir::open("src/some-non-existent-file").unwrap();
+    }
+
+    #[test]
+    fn test_list() {
+        let dir = Dir::open("src").unwrap();
+        let me = dir.list_dir(".").unwrap();
+        assert!(me.collect::<Result<Vec<_>, _>>().unwrap()
+                .iter().find(|x| {
+                    x.file_name() == Path::new("lib.rs").as_os_str()
+                })
+                .is_some());
+    }
+
+    #[test]
+    fn test_from_raw_fd_checked() {
+        let fd = Dir::open(".").unwrap().into_raw_fd();
+        let dir = unsafe { Dir::from_raw_fd_checked(fd) }.unwrap();
+        let filefd = dir.open_file("src/lib.rs").unwrap().into_raw_fd();
+        match unsafe { Dir::from_raw_fd_checked(filefd) } {
+            Ok(_) => assert!(false, "from_raw_fd_checked succeeded on a non-directory fd!"),
+            Err(e) => assert_eq!(e.raw_os_error().unwrap(), libc::ENOTDIR)
+        }
+    }
+
+    #[test]
+    fn test_try_clone() {
+        let d = Dir::open(".").unwrap();
+        let d2 = d.try_clone().unwrap();
+        drop(d);
+        let _file = d2.open_file("src/lib.rs").unwrap();
+    }
+}