Add lstat

2 files changed, 72 insertions, 5 deletions

diff --git a/src/sys/stat.rs b/src/sys/stat.rs
index d98d20ec..cafb36d9 100644
--- a/src/sys/stat.rs
+++ b/src/sys/stat.rs
@@ -1,7 +1,7 @@
 pub use libc::dev_t;
 pub use libc::stat as FileStat;
 
-use {Error, Result, NixPath, AsExtStr,from_ffi};
+use {Error, Result, NixPath, AsExtStr, from_ffi};
 use errno::Errno;
 use fcntl::Fd;
 use libc::mode_t;
@@ -10,7 +10,7 @@ use std::mem;
 
 mod ffi {
     use libc::{c_char, c_int, mode_t, dev_t};
-    pub use libc::{stat, fstat};
+    pub use libc::{stat, fstat, lstat};
 
     extern {
         pub fn mknod(pathname: *const c_char, mode: mode_t, dev: dev_t) -> c_int;
@@ -94,6 +94,21 @@ pub fn stat<P: ?Sized + NixPath>(path: &P) -> Result<FileStat> {
     Ok(dst)
 }
 
+pub fn lstat<P: ?Sized + NixPath>(path: &P) -> Result<FileStat> {
+    let mut dst = unsafe { mem::uninitialized() };
+    let res = try!(path.with_nix_path(|osstr| {
+        unsafe {
+            ffi::lstat(osstr.as_ext_str(), &mut dst as *mut FileStat)
+        }
+    }));
+
+    if res < 0 {
+        return Err(Error::Sys(Errno::last()));
+    }
+
+    Ok(dst)
+}
+
 pub fn fstat(fd: Fd) -> Result<FileStat> {
     let mut dst = unsafe { mem::uninitialized() };
     let res = unsafe { ffi::fstat(fd, &mut dst as *mut FileStat) };
diff --git a/test/test_stat.rs b/test/test_stat.rs
index abc58b4d..44091a7c 100644
--- a/test/test_stat.rs
+++ b/test/test_stat.rs
@@ -1,9 +1,14 @@
-use nix::sys::stat::{stat, fstat};
+use std::fs;
+use std::str;
+
+use libc::consts::os::posix88;
+
+use nix::sys::stat::{stat, fstat, lstat};
 
 use nix::fcntl::open;
 use nix::unistd::{close, unlink};
-use nix::fcntl::O_CREAT;
-use nix::sys::stat::{FileStat, S_IWUSR};
+use nix::fcntl::{O_CREAT, O_RDONLY};
+use nix::sys::stat::{FileStat, S_IWUSR, S_IRUSR};
 use nix::Result;
 
 fn assert_stat_results(stat_result: Result<FileStat>) {
@@ -24,6 +29,28 @@ fn assert_stat_results(stat_result: Result<FileStat>) {
     }
 }
 
+fn assert_lstat_results(stat_result: Result<FileStat>) {
+    match stat_result {
+        Ok(stats) => {
+            assert!(stats.st_dev > 0);      // must be positive integer, exact number machine dependent
+            assert!(stats.st_ino > 0);      // inode is positive integer, exact number machine dependent
+            assert!(stats.st_mode > 0);     // must be positive integer
+            assert!(stats.st_mode & posix88::S_IFMT
+                    == posix88::S_IFLNK); // should be a link
+            assert!(stats.st_nlink == 1);   // there links created, must be 1
+            assert!(stats.st_uid > 0);      // must be positive integer
+            assert!(stats.st_gid > 0);      // must be positive integer
+            assert!(stats.st_rdev == 0);    // no special device
+            assert!(stats.st_size > 0);    // size is > 0 because it points to another file
+            assert!(stats.st_blksize > 0);  // must be positive integer, exact number machine dependent
+
+            // st_blocks depends on whether the machine's file system uses fast
+            // or slow symlinks, so just make sure it's not negative
+            assert!(stats.st_blocks >= 0);
+        }
+        Err(_) => panic!("stat call failed") // if stats system call fails, something is seriously wrong on that machine
+    }
+}
 
 #[test]
 fn test_stat_and_fstat() {
@@ -39,3 +66,28 @@ fn test_stat_and_fstat() {
     close(fd).unwrap();
     unlink(filename).unwrap();
 }
+
+#[test]
+fn test_stat_fstat_lstat() {
+    let filename = b"target/bar.txt".as_ref();
+    let linkname = b"target/barlink".as_ref();
+
+    open(filename, O_CREAT, S_IWUSR | S_IRUSR).unwrap();  // create empty file
+    fs::soft_link("bar.txt", str::from_utf8(linkname).unwrap()).unwrap();
+    let fd = open(linkname, O_RDONLY, S_IRUSR).unwrap();
+
+    // should be the same result as calling stat,
+    // since it's a regular file
+    let stat_result = lstat(filename);
+    assert_stat_results(stat_result);
+
+    let lstat_result = lstat(linkname);
+    assert_lstat_results(lstat_result);
+
+    let fstat_result = fstat(fd);
+    assert_stat_results(fstat_result);
+
+    close(fd).unwrap();
+    unlink(linkname).unwrap();
+    unlink(filename).unwrap();
+}