[WIP] add support for rename/renameat

CHANGELOG.md

@@ -24,6 +24,9 @@ This project adheres to [Semantic Versioning](http://semver.org/).
   ([#739](https://github.com/nix-rust/nix/pull/739))
 - Added nix::sys::ptrace::detach. 
   ([#749](https://github.com/nix-rust/nix/pull/749))
+- Added nix::fcntl::{rename, renameat}.
+  ([#752](https://github.com/nix-rust/nix/pull/752))
+
 
 ### Changed
 - Renamed existing `ptrace` wrappers to encourage namespacing ([#692](https://github.com/nix-rust/nix/pull/692))

src/fcntl.rs

@@ -206,6 +206,35 @@ libc_bitflags!(
     }
 );
 
+/// Change the name or location of a file
+/// ([posix specification](http://pubs.opengroup.org/onlinepubs/9699919799/functions/rename.html)).
+pub fn rename<P1: ?Sized + NixPath, P2: ?Sized + NixPath>(oldpath: &P1, newpath: &P2) -> Result<()> {
+    let res = try!(try!(oldpath.with_nix_path(|old|
+        newpath.with_nix_path(|new|
+            unsafe { 
+                libc::rename(old.as_ptr() as *const c_char, new.as_ptr() as *const c_char)
+            }
+        )
+    )));
+
+    Errno::result(res).map(drop)
+}
+
+/// Change the name or location of a file
+/// ([posix specification](http://pubs.opengroup.org/onlinepubs/9699919799/functions/renameat.html)).
+pub fn renameat<P1: ?Sized + NixPath, P2: ?Sized + NixPath>(olddirfd: RawFd, oldpath: &P1, newdirfd: RawFd, newpath: &P2) -> Result<()> {
+    let res = try!(try!(oldpath.with_nix_path(|old|
+        newpath.with_nix_path(|new|
+            unsafe { 
+                libc::renameat(olddirfd, old.as_ptr() as *const c_char,
+                               newdirfd, new.as_ptr() as *const c_char)
+            }
+        )
+    )));
+
+    Errno::result(res).map(drop)
+}
+
 pub enum FcntlArg<'a> {
     F_DUPFD(RawFd),
     F_DUPFD_CLOEXEC(RawFd),

test/test_fcntl.rs

@@ -1,8 +1,9 @@
-use nix::fcntl::{openat, open, OFlag, O_RDONLY, readlink, readlinkat};
+use nix::fcntl::{openat, open, OFlag, O_RDONLY, readlink, readlinkat, rename, renameat};
 use nix::sys::stat::Mode;
 use nix::unistd::{close, read};
 use tempdir::TempDir;
 use tempfile::NamedTempFile;
+use std::fs::File;
 use std::io::prelude::*;
 use std::os::unix::fs;
 
@@ -47,6 +48,24 @@ fn test_readlink() {
                src.to_str().unwrap());
 }
 
+#[test]
+fn test_rename_renameat() {
+    let tempdir = TempDir::new("nix-test_rename")
+        .unwrap_or_else(|e| panic!("tempdir failed: {}", e));
+    let src = tempdir.path().join("a");
+    let dst = tempdir.path().join("b");
+    File::create(&src).unwrap();
+
+    rename(&src, &dst).unwrap();
+    assert!(dst.exists());
+
+    let dir = open(tempdir.path(),
+                   OFlag::empty(),
+                   Mode::empty()).unwrap();
+    renameat(dir, "b", dir, "a").unwrap();
+    assert!(src.exists());
+}
+
 #[cfg(any(target_os = "linux", target_os = "android"))]
 mod linux_android {
     use std::io::prelude::*;