Implement tty

Makefile

@@ -25,6 +25,7 @@ PROGS       := \
   wc \
   whoami \
   yes \
+  tty \
 
 BUILD       ?= $(PROGS)
 

tty/tty.rs

@@ -0,0 +1,68 @@
+#[crate_id(name="tty", version="1.0.0", author="Alan Andrade")];
+
+
+/*
+ * This file is part of the uutils coreutils package.
+ *
+ * (c) Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * Synced with http://lingrok.org/xref/coreutils/src/tty.c
+ */
+
+extern mod extra;
+
+use std::{libc,str,os};
+use std::io::stdio::stderr;
+use extra::getopts::{optflag,getopts};
+
+extern {
+    fn ttyname(filedesc: libc::c_int) -> *libc::c_char;
+    fn isatty(filedesc: libc::c_int) -> libc::c_int;
+}
+
+fn main () {
+    let args = os::args();
+
+    let options = [
+        optflag("s")
+    ];
+
+    let silent = match getopts(args.tail(), options) {
+        Ok(m) => {
+            m.opt_present("s")
+        },
+        Err(f) => {
+            println(f.to_err_msg());
+            usage();
+            return
+        }
+    };
+
+    let tty = unsafe { str::raw::from_c_str(ttyname(libc::STDIN_FILENO)) };
+
+    if !silent {
+        if !tty.is_whitespace() {
+            println(tty);
+        } else {
+            println("not a tty");
+        }
+    }
+
+    let exit_code = unsafe {
+        if isatty(libc::STDIN_FILENO) == 1 {
+            libc::EXIT_SUCCESS
+        } else {
+            libc::EXIT_FAILURE
+        }
+    };
+
+    os::set_exit_status(exit_code as int);
+}
+
+fn usage () {
+    writeln!(&mut stderr() as &mut Writer, "usage: tty [-s]");
+    os::set_exit_status(2);
+}