From f6065e81811227858970310d15f7ecb38b177926 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Thalheim?= <joerg@thalheim.io>
Date: Thu, 30 Mar 2017 12:32:39 +0200
Subject: [PATCH] add support for `futimens/utimensat`

---
 CHANGELOG.md      |  2 ++
 src/sys/stat.rs   | 71 +++++++++++++++++++++++++++++++++++++++++++++++
 test/test_stat.rs | 17 ++++++++++++
 3 files changed, 90 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 36b528ca91..4044391655 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,6 +24,8 @@ 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::stat::{futimens, utimensat}`
+  ([#761](https://github.com/nix-rust/nix/pull/761))
 
 ### Changed
 - Renamed existing `ptrace` wrappers to encourage namespacing ([#692](https://github.com/nix-rust/nix/pull/692))
diff --git a/src/sys/stat.rs b/src/sys/stat.rs
index 7a0b3970ce..2b615446fc 100644
--- a/src/sys/stat.rs
+++ b/src/sys/stat.rs
@@ -7,6 +7,8 @@ use libc::{self, mode_t};
 use std::mem;
 use std::os::unix::io::RawFd;
 
+pub use self::linux::*;
+
 libc_bitflags!(
     pub struct SFlag: mode_t {
         S_IFIFO;
@@ -121,3 +123,72 @@ pub fn fstatat<P: ?Sized + NixPath>(dirfd: RawFd, pathname: &P, f: AtFlags) -> R
     Ok(dst)
 }
 
+#[cfg(target_os = "linux")]
+mod linux {
+    use {Errno, Result, NixPath};
+    use std::os::unix::io::RawFd;
+    use libc;
+    use fcntl::AtFlags;
+    use sys::time::TimeSpec;
+
+    /// A file timestamp.
+    pub enum UtimeSpec {
+        /// File timestamp is set to the current time.
+        Now,
+        /// The corresponding file timestamp is left unchanged.
+        Omit,
+        /// File timestamp is set to value
+        Time(TimeSpec)
+    }
+
+    impl <'a> From<&'a UtimeSpec> for libc::timespec {
+        fn from(time: &'a UtimeSpec) -> libc::timespec { 
+            match time {
+                &UtimeSpec::Now => libc::timespec {
+                    tv_sec: 0,
+                    tv_nsec: libc::UTIME_NOW,
+                },
+                &UtimeSpec::Omit => libc::timespec {
+                    tv_sec: 0,
+                    tv_nsec: libc::UTIME_OMIT,
+                },
+                &UtimeSpec::Time(spec) => *spec.as_ref()
+            }
+        }
+    }
+
+    /// Change file timestamps with nanosecond precision
+    /// (see [utimensat(2)](http://man7.org/linux/man-pages/man2/utimensat.2.html)).
+    pub fn utimensat<P: ?Sized + NixPath>(dirfd: RawFd,
+                                          pathname: &P,
+                                          atime: &UtimeSpec,
+                                          mtime: &UtimeSpec,
+                                          flags: AtFlags) -> Result<()> {
+        let time = [atime.into(), mtime.into()];
+        let res = try!(pathname.with_nix_path(|cstr| {
+            unsafe {
+                libc::utimensat(dirfd,
+                                cstr.as_ptr(),
+                                time.as_ptr() as *const libc::timespec,
+                                flags.bits())
+            }
+        }));
+
+        Errno::result(res).map(drop)
+    }
+
+    /// Change file timestamps with nanosecond precision
+    /// (see [futimens(2)](http://man7.org/linux/man-pages/man2/futimens.2.html)).
+    pub fn futimens(fd: RawFd,
+                    atime: &UtimeSpec,
+                    mtime: &UtimeSpec) -> Result<()> {
+        let time = [atime.into(), mtime.into()];
+        let res = unsafe {
+            libc::futimens(fd, time.as_ptr() as *const libc::timespec)
+        };
+    
+        Errno::result(res).map(drop)
+    }
+}
+#[cfg(not(target_os = "linux"))]
+mod linux { }
diff --git a/test/test_stat.rs b/test/test_stat.rs
index 765d4fa191..462252a519 100644
--- a/test/test_stat.rs
+++ b/test/test_stat.rs
@@ -110,3 +110,20 @@ fn test_stat_fstat_lstat() {
     let fstat_result = fstat(link.as_raw_fd());
     assert_stat_results(fstat_result);
 }
+
+#[test]
+#[cfg(target_os = "linux")]
+fn test_utime() {
+    use std::time::UNIX_EPOCH;
+    use nix::sys::time::{TimeSpec, TimeValLike};
+
+    let tempfile = NamedTempFile::new().unwrap();
+    utimensat(0, // is ignored, if pathname is absolute path
+              tempfile.path(),
+              &UtimeSpec::Time(TimeSpec::zero()),
+              &UtimeSpec::Time(TimeSpec::zero()),
+              fcntl::AtFlags::empty()).unwrap();
+    let mtime = tempfile.metadata().unwrap().modified().unwrap();
+
+    assert_eq!(mtime, UNIX_EPOCH);
+}