Merge branch 'ctermid' into 'master'

Implement ctermid()

See merge request redox-os/relibc!490

src/header/stdio/constants.rs

@@ -24,6 +24,8 @@ pub const _IOFBF: c_int = 0;
 pub const _IOLBF: c_int = 1;
 pub const _IONBF: c_int = 2;
 
+// /dev/tty + nul
+pub const L_ctermid: usize = 9;
 // form of name is /XXXXXX, so 7
 pub const L_tmpnam: c_int = 7;
 // 36^6 (26 letters + 10 digits) is larger than i32::MAX, so just set to that

src/header/stdio/mod.rs

@@ -278,9 +278,15 @@ pub unsafe extern "C" fn clearerr(stream: *mut FILE) {
     stream.flags &= !(F_EOF | F_ERR);
 }
 
-// #[no_mangle]
-pub extern "C" fn ctermid(_s: *mut c_char) -> *mut c_char {
-    unimplemented!();
+#[no_mangle]
+pub unsafe extern "C" fn ctermid(s: *mut c_char) -> *mut c_char {
+    static mut TERMID: [u8; L_ctermid] = *b"/dev/tty\0";
+
+    if s.is_null() {
+        return TERMID.as_mut_ptr() as *mut c_char;
+    }
+
+    strncpy(s, TERMID.as_mut_ptr() as *mut c_char, L_ctermid)
 }
 
 // #[no_mangle]