1 files changed, 82 insertions, 0 deletions
diff --git a/sysdeps/posix/ttyname.c b/sysdeps/posix/ttyname.c
new file mode 100644
index 0000000000..50e3c79341
--- /dev/null
+++ b/sysdeps/posix/ttyname.c
@@ -0,0 +1,82 @@
+/* Copyright (C) 1991, 1992, 1993 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <errno.h>
+#include <limits.h>
+#include <stddef.h>
+#include <dirent.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+
+char *__ttyname = NULL;
+
+/* Return the pathname of the terminal FD is open on, or NULL on errors.
+   The returned storage is good only until the next call to this function.  */
+char *
+DEFUN(ttyname, (fd), int fd)
+{
+  static CONST char dev[] = "/dev";
+  static char *name;
+  static size_t namelen = 0;
+  struct stat st;
+  dev_t mydev;
+  ino_t myino;
+  DIR *dirstream;
+  struct dirent *d;
+  int save = errno;
+
+  if (fstat (fd, &st) < 0)
+    return NULL;
+  mydev = st.st_dev;
+  myino = st.st_ino;
+
+  dirstream = opendir (dev);
+  if (dirstream == NULL)
+    return NULL;
+
+  while ((d = readdir (dirstream)) != NULL)
+    if (d->d_fileno == myino)
+      {
+	if (sizeof (dev) + d->d_namlen + 1 > namelen)
+	  {
+	    free (name);
+	    namelen = 2 * (sizeof (dev) + d->d_namlen + 1); /* Big enough.  */
+	    name = malloc (namelen);
+	    if (! name)
+	      return NULL;
+	    (void) memcpy (name, dev, sizeof (dev) - 1);
+	    name[sizeof (dev) - 1] = '/';
+	  }
+	(void) memcpy (&name[sizeof (dev)], d->d_name, d->d_namlen + 1);
+	if (stat (name, &st) == 0 && st.st_dev == mydev)
+	  {
+	    (void) closedir (dirstream);
+	    __ttyname = name;
+	    errno = save;
+	    return name;
+	  }
+      }
+
+  (void) closedir (dirstream);
+  errno = save;
+  return NULL;
+}