unix: open ttyname instead of /dev/tty

Find the real name of the tty using ttyname_r(3) instead of
opening "/dev/tty" which causes trouble if the fd doesn't point to the
controlling terminal.

PR-URL: https://github.com/libuv/libuv/pull/779
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Saúl Ibarra Corretgé <saghul@gmail.com>

1 files changed, 12 insertions, 4 deletions

diff --git a/docs/src/tty.rst b/docs/src/tty.rst
index 655dca9c..01a05852 100644
--- a/docs/src/tty.rst
+++ b/docs/src/tty.rst
@@ -58,14 +58,22 @@ API
     `readable`, specifies if you plan on calling :c:func:`uv_read_start` with
     this stream. stdin is readable, stdout is not.
 
-    On Unix this function will try to open ``/dev/tty`` and use it if the passed
-    file descriptor refers to a TTY. This lets libuv put the tty in non-blocking
-    mode without affecting other processes that share the tty.
+    On Unix this function will determine the path of the fd of the terminal
+    using :man:`ttyname_r(3)`, open it, and use it if the passed file descriptor
+    refers to a TTY. This lets libuv put the tty in non-blocking mode without
+    affecting other processes that share the tty.
+
+    This function is not thread safe on systems that don't support
+    ioctl TIOCGPTN or TIOCPTYGNAME, for instance OpenBSD and Solaris.
 
     .. note::
-        If opening ``/dev/tty`` fails, libuv falls back to blocking writes for
+        If reopening the TTY fails, libuv falls back to blocking writes for
         non-readable TTY streams.
 
+    .. versionchanged:: 1.9.0: the path of the TTY is determined by
+                        :man:`ttyname_r(3)`. In earlier versions libuv opened
+                        `/dev/tty` instead.
+
     .. versionchanged:: 1.5.0: trying to initialize a TTY stream with a file
                         descriptor that refers to a file returns `UV_EINVAL`
                         on UNIX.