2 files changed, 6 insertions, 0 deletions
diff --git a/sysdeps/posix/ttyname.c b/sysdeps/posix/ttyname.c
index b0650b38b0..7c7ed2428a 100644
--- a/sysdeps/posix/ttyname.c
+++ b/sysdeps/posix/ttyname.c
@@ -44,6 +44,9 @@ DEFUN(ttyname, (fd), int fd)
   struct dirent *d;
   int save = errno;
 
+  if (!__isatty (fd))
+    return NULL;
+
   if (fstat (fd, &st) < 0)
     return NULL;
   mydev = st.st_dev;
diff --git a/sysdeps/posix/ttyname_r.c b/sysdeps/posix/ttyname_r.c
index a05dbd5be3..e6172f1c97 100644
--- a/sysdeps/posix/ttyname_r.c
+++ b/sysdeps/posix/ttyname_r.c
@@ -54,6 +54,9 @@ __ttyname_r (fd, buf, buflen)
       return -1;
     }
 
+  if (!__isatty (fd))
+    return -1;
+
   if (fstat (fd, &st) < 0)
     return -1;
   mydev = st.st_dev;