From c00649152177ef9e6c9b647655eb676c766fe375 Mon Sep 17 00:00:00 2001
From: Kevin Wern <kevin.m.wern@gmail.com>
Date: Sun, 9 Jun 2019 21:10:10 -0400
Subject: [PATCH] sys/stat: implement mkdirat

---
 CHANGELOG.md      |  2 ++
 src/sys/stat.rs   |  8 ++++++++
 test/test_stat.rs | 42 ++++++++++++++++++++++++++++++++++++++----
 3 files changed, 48 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 16b7992dcc..c72957566b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
   types that support them. ([#1035](https://github.com/nix-rust/nix/pull/1035))
 - Added `copy_file_range` wrapper
   ([#1069](https://github.com/nix-rust/nix/pull/1069))
+- Add `mkdirat`.
+  ([#1084](https://github.com/nix-rust/nix/pull/1084))
 
 ### Changed
 - Support for `ifaddrs` now present when building for Android.
diff --git a/src/sys/stat.rs b/src/sys/stat.rs
index 1e0936ed86..66c8c9dd1b 100644
--- a/src/sys/stat.rs
+++ b/src/sys/stat.rs
@@ -284,3 +284,11 @@ pub fn utimensat<P: ?Sized + NixPath>(
 
     Errno::result(res).map(drop)
 }
+
+pub fn mkdirat<P: ?Sized + NixPath>(fd: RawFd, path: &P, mode: Mode) -> Result<()> {
+    let res = path.with_nix_path(|cstr| {
+        unsafe { libc::mkdirat(fd, cstr.as_ptr(), mode.bits() as mode_t) }
+    })?;
+
+    Errno::result(res).map(drop)
+}
diff --git a/test/test_stat.rs b/test/test_stat.rs
index b9da7fc3ea..1173455fae 100644
--- a/test/test_stat.rs
+++ b/test/test_stat.rs
@@ -1,13 +1,15 @@
 use std::fs::{self, File};
-use std::os::unix::fs::symlink;
+use std::os::unix::fs::{symlink, PermissionsExt};
 use std::os::unix::prelude::AsRawFd;
 use std::time::{Duration, UNIX_EPOCH};
+use std::path::Path;
 
 #[cfg(not(any(target_os = "netbsd")))]
-use libc::{S_IFMT, S_IFLNK};
+use libc::{S_IFMT, S_IFLNK, mode_t};
 
-use nix::fcntl;
-use nix::sys::stat::{self, fchmod, fchmodat, futimens, stat, utimes, utimensat};
+use nix::{fcntl, Error};
+use nix::errno::{Errno};
+use nix::sys::stat::{self, fchmod, fchmodat, futimens, stat, utimes, utimensat, mkdirat};
 #[cfg(any(target_os = "linux",
           target_os = "haiku",
           target_os = "ios",
@@ -260,3 +262,35 @@ fn test_utimensat() {
               UtimensatFlags::FollowSymlink).unwrap();
     assert_times_eq(500, 800, &fs::metadata(&fullpath).unwrap());
 }
+
+#[test]
+fn test_mkdirat_success_path() {
+    let tempdir = tempfile::tempdir().unwrap();
+    let filename = "example_subdir";
+    let dirfd = fcntl::open(tempdir.path(), fcntl::OFlag::empty(), stat::Mode::empty()).unwrap();
+    assert!((mkdirat(dirfd, filename, Mode::S_IRWXU)).is_ok());
+    assert!(Path::exists(&tempdir.path().join(filename)));
+}
+
+#[test]
+fn test_mkdirat_success_mode() {
+    let expected_bits = stat::SFlag::S_IFDIR.bits() | stat::Mode::S_IRWXU.bits();
+    let tempdir = tempfile::tempdir().unwrap();
+    let filename = "example_subdir";
+    let dirfd = fcntl::open(tempdir.path(), fcntl::OFlag::empty(), stat::Mode::empty()).unwrap();
+    assert!((mkdirat(dirfd, filename, Mode::S_IRWXU)).is_ok());
+    let permissions = fs::metadata(tempdir.path().join(filename)).unwrap().permissions();
+    let mode = permissions.mode();
+    assert_eq!(mode as mode_t, expected_bits)
+}
+
+#[test]
+fn test_mkdirat_fail() {
+    let tempdir = tempfile::tempdir().unwrap();
+    let not_dir_filename= "example_not_dir";
+    let filename = "example_subdir_dir";
+    let dirfd = fcntl::open(&tempdir.path().join(not_dir_filename), fcntl::OFlag::O_CREAT,
+                            stat::Mode::empty()).unwrap();
+    let result = mkdirat(dirfd, filename, Mode::S_IRWXU).unwrap_err();
+    assert_eq!(result, Error::Sys(Errno::ENOTDIR));
+}