2 files changed, 27 insertions, 8 deletions

diff --git a/src/unistd.rs b/src/unistd.rs
index 34e9b6a9..f8e17153 100644
--- a/src/unistd.rs
+++ b/src/unistd.rs
@@ -3,12 +3,13 @@
 use {Errno, Error, Result, NixPath};
 use fcntl::{fcntl, OFlag, O_NONBLOCK, O_CLOEXEC, FD_CLOEXEC};
 use fcntl::FcntlArg::{F_SETFD, F_SETFL};
-use libc::{self, c_char, c_void, c_int, c_uint, size_t, pid_t, off_t, uid_t, gid_t};
+use libc::{self, c_char, c_void, c_int, c_uint, size_t, pid_t, off_t, uid_t, gid_t, mode_t};
 use std::mem;
 use std::ffi::{CString,CStr};
+use std::path::PathBuf;
 use std::os::unix::io::RawFd;
 use void::Void;
-use std::path::PathBuf;
+use sys::stat::Mode;
 
 #[cfg(any(target_os = "linux", target_os = "android"))]
 pub use self::linux::*;
@@ -112,10 +113,14 @@ pub fn chdir<P: ?Sized + NixPath>(path: &P) -> Result<()> {
     Errno::result(res).map(drop)
 }
 
-// #[inline]
-// pub fn mkdir<P: ?Sized + NixPath>(path: &P) -> Result<()> {
-//     Errno::result(0)
-// }
+#[inline]
+pub fn mkdir<P: ?Sized + NixPath>(path: &P, mode: Mode) -> Result<()> {
+    let res = try!(path.with_nix_path(|cstr| {
+        unsafe { libc::mkdir(cstr.as_ptr(), mode.bits() as mode_t) }
+    }));
+
+    Errno::result(res).map(drop)
+}
 
 #[inline]
 pub fn getcwd() -> Result<PathBuf> {
@@ -137,7 +142,8 @@ pub fn getcwd() -> Result<PathBuf> {
                 return Ok(PathBuf::from(&s));
             } else {
                 let error = Errno::last();
-                if error == Errno::ERANGE {
+                // ERANGE means buffer was too small to store directory name
+                if error != Errno::ERANGE {
                     return Err(Error::Sys(error));
                 }                
             }
diff --git a/test/test_unistd.rs b/test/test_unistd.rs
index 2b6182b6..26746426 100644
--- a/test/test_unistd.rs
+++ b/test/test_unistd.rs
@@ -3,6 +3,8 @@ extern crate tempdir;
 use nix::unistd::*;
 use nix::unistd::ForkResult::*;
 use nix::sys::wait::*;
+use nix::sys::stat;
+use std::iter;
 use std::ffi::CString;
 
 use std::io::{Write, Read};
@@ -129,7 +131,18 @@ fn test_getcwd() {
   } else {
     "/tmp/"
   };
-  let tmp_dir = TempDir::new_in(base, "test_getcwd").expect("create temp dir").into_path();
+  let mut tmp_dir = TempDir::new_in(base, "test_getcwd").expect("create temp dir").into_path();
+  assert!(chdir(tmp_dir.as_path()).is_ok());
+  assert_eq!(getcwd().unwrap(), tmp_dir);
+
+  // make path 500 chars longer so that buffer doubling in getcwd kicks in.
+  // Note: One path cannot be longer than 255 bytes (NAME_MAX)
+  // whole path cannot be longer than PATH_MAX (usually 4096 on linux, 1024 on macos)
+  for _ in 0..5 {
+    let newdir = iter::repeat("a").take(100).collect::<String>();
+    tmp_dir.push(newdir);
+    assert!(mkdir(tmp_dir.as_path(), stat::S_IRWXU).is_ok());
+  }
   assert!(chdir(tmp_dir.as_path()).is_ok());
   assert_eq!(getcwd().unwrap(), tmp_dir);
 }