diff --git a/lib/pid_output.c b/lib/pid_output.c
new file mode 100644
index 0000000..4146244
--- /dev/null
+++ b/lib/pid_output.c
@@ -0,0 +1,77 @@
+/*
+ * Process id output.
+ * Copyright (C) 1998, 1999 Kunihiro Ishiguro
+ *
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * GNU Zebra 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Zebra; see the file COPYING.  If not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.  
+ */
+
+#include <zebra.h>
+
+pid_t
+pid_output (char *path)
+{
+  FILE *fp;
+  pid_t pid;
+
+  pid = getpid();
+
+  fp = fopen (path, "w");
+  if (fp != NULL) 
+    {
+      fprintf (fp, "%d\n", (int) pid);
+      fclose (fp);
+      return -1;
+    }
+  return pid;
+}
+
+pid_t
+pid_output_lock (char *path)
+{
+  int tmp;
+  int fd;
+  pid_t pid;
+  char buf[16], *p;
+
+  pid = getpid ();
+
+  fd = open (path, O_RDWR | O_CREAT | O_EXCL, 0644);
+  if (fd < 0)
+    {
+      fd = open (path, O_RDONLY);
+      if (fd < 0)
+        fprintf (stderr, "Can't creat pid lock file, exit\n");
+      else
+        {
+          read (fd, buf, sizeof (buf));
+          if ((p = index (buf, '\n')) != NULL)
+            *p = 0;
+          fprintf (stderr, "Another process(%s) running, exit\n", buf);
+        }
+      exit (-1);
+    }
+  else
+    {
+      sprintf (buf, "%d\n", (int) pid);
+      tmp = write (fd, buf, strlen (buf));
+      close (fd);
+    }
+
+  return pid;
+}
+