implemented getcwd (returning Result<PathBuf>, reconciling all calls to expect into proper try handling), needs testing still

2 files changed, 46 insertions, 1 deletions

diff --git a/src/unistd.rs b/src/unistd.rs
index d4da60da..34e9b6a9 100644
--- a/src/unistd.rs
+++ b/src/unistd.rs
@@ -5,9 +5,10 @@ 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 std::mem;
-use std::ffi::CString;
+use std::ffi::{CString,CStr};
 use std::os::unix::io::RawFd;
 use void::Void;
+use std::path::PathBuf;
 
 #[cfg(any(target_os = "linux", target_os = "android"))]
 pub use self::linux::*;
@@ -111,6 +112,45 @@ 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 getcwd() -> Result<PathBuf> {
+    let mut buf = Vec::with_capacity(512);
+    loop {
+        unsafe {
+            let ptr = buf.as_mut_ptr() as *mut libc::c_char;
+
+            // The buffer must be large enough to store the absolute pathname plus
+            // a terminating null byte, or else null is returned.
+            // To safely handle this we start with a reasonable size (512 bytes)
+            // and double the buffer size upon every error
+            if !libc::getcwd(ptr, buf.capacity()).is_null() {
+                let len = CStr::from_ptr(ptr).to_bytes().len();
+                buf.set_len(len);
+                buf.shrink_to_fit();
+                let s = try!(CString::new(buf).map_err(|_| Error::Sys(Errno::EILSEQ)));
+                let s = try!(s.into_string().map_err(|_| Error::Sys(Errno::EILSEQ)));
+                return Ok(PathBuf::from(&s));
+            } else {
+                let error = Errno::last();
+                if error == Errno::ERANGE {
+                    return Err(Error::Sys(error));
+                }                
+            }
+
+            // Trigger the internal buffer resizing logic of `Vec` by requiring
+            // more space than the current capacity.
+            let cap = buf.capacity();
+            buf.set_len(cap);
+            buf.reserve(1);
+        }
+    }    
+}
+
 #[inline]
 pub fn chown<P: ?Sized + NixPath>(path: &P, owner: Option<uid_t>, group: Option<gid_t>) -> Result<()> {
     let res = try!(path.with_nix_path(|cstr| {
diff --git a/test/test_unistd.rs b/test/test_unistd.rs
index 188bfbeb..48891bc3 100644
--- a/test/test_unistd.rs
+++ b/test/test_unistd.rs
@@ -120,6 +120,11 @@ macro_rules! execve_test_factory(
 );
 
 #[test]
+fn test_getcwd() {
+  println!("{}", getcwd().unwrap().display());
+}
+
+#[test]
 fn test_lseek() {
     const CONTENTS: &'static [u8] = b"abcdef123456";
     let mut tmp = tempfile().unwrap();