Make vty and log thread safe under single mutex.

6 files changed, 515 insertions, 210 deletions

diff --git a/bgpd/bgp_main.c b/bgpd/bgp_main.c
index 9d14683c..3568d2b1 100644
--- a/bgpd/bgp_main.c
+++ b/bgpd/bgp_main.c
@@ -404,9 +404,9 @@ main (int argc, char **argv)
   /* Initializations. */
   srand (time (NULL));
   signal_init (master, Q_SIGC(bgp_signals), bgp_signals);
-  zprivs_init (&bgpd_privs);
+  zprivs_init_r (&bgpd_privs);
   cmd_init (1);
-  vty_init (master);
+  vty_init_r (master);
   memory_init ();
 
   /* BGP related initialization.  */
diff --git a/configure.ac b/configure.ac
index 634d6359..aeed0d1b 100755
--- a/configure.ac
+++ b/configure.ac
@@ -128,6 +128,7 @@ if test "x${cflags_specified}" = "x" ; then
   	CFLAGS="${CFLAGS} -Wbad-function-cast -Wwrite-strings"
   	CFLAGS="${CFLAGS} -Wmissing-prototypes -Wmissing-declarations"
   	CFLAGS="${CFLAGS} -Wchar-subscripts -Wcast-qual"
+  	CFLAGS="${CFLAGS} -pthread"
   	# TODO: conditionally addd -Wpacked if handled
   	AC_MSG_RESULT([gcc default])
   	;;
diff --git a/lib/log.c b/lib/log.c
index 9d66fc5d..81624f58 100644
--- a/lib/log.c
+++ b/lib/log.c
@@ -36,13 +36,22 @@
 #endif
 #include "qpthreads.h"
 
-/* Needs to be qpthread safe */
-static qpt_mutex_t* mx = NULL;
+#ifdef NDEBUG
+#define LOCK qpt_mutex_lock(vty_mutex);
+#define UNLOCK qpt_mutex_unlock(vty_mutex);
+#else
+#define LOCK qpt_mutex_lock(vty_mutex);++vty_lock_count;
+#define UNLOCK --vty_lock_count;qpt_mutex_unlock(vty_mutex);
+#endif
+
+/* log is protected by the same mutext as vty, see comments in vty.c */
 
 /* prototypes */
-static int do_reset_file (struct zlog *zl);
-static size_t do_timestamp(int timestamp_precision, char *buf, size_t buflen);
+static int uzlog_reset_file (struct zlog *zl);
 static void zlog_abort (const char *mess) __attribute__ ((noreturn));
+static void vzlog (struct zlog *zl, int priority, const char *format, va_list args);
+static void uzlog_backtrace(int priority);
+static void uvzlog (struct zlog *zl, int priority, const char *format, va_list args);
 
 static int logfile_fd = -1;	/* Used in signal handler. */
 
@@ -75,34 +84,22 @@ const char *zlog_priority[] =
   "debugging",
   NULL,
 };
-  
-void
-zlog_init_r(void)
-{
-  mx = qpt_mutex_init(mx, qpt_mutex_quagga);
-}
-
-void
-zlog_destroy_r(void)
-{
-  mx = qpt_mutex_destroy(mx, 1);
-}
 
-
 /* For time string format. */
 
 size_t
 quagga_timestamp(int timestamp_precision, char *buf, size_t buflen)
 {
   size_t result;
-  qpt_mutex_lock(mx);
-  result = do_timestamp(timestamp_precision, buf, buflen);
-  qpt_mutex_unlock(mx);
+  LOCK
+  result = uquagga_timestamp(timestamp_precision, buf, buflen);
+  UNLOCK
   return result;
 }
 
-static size_t
-do_timestamp(int timestamp_precision, char *buf, size_t buflen)
+/* unprotected version for when mutex already held */
+size_t
+uquagga_timestamp(int timestamp_precision, char *buf, size_t buflen)
 {
   static struct {
     time_t last;
@@ -175,21 +172,29 @@ time_print(FILE *fp, struct timestamp_control *ctl)
 {
   if (!ctl->already_rendered)
     {
-      ctl->len = do_timestamp(ctl->precision, ctl->buf, sizeof(ctl->buf));
+      ctl->len = uquagga_timestamp(ctl->precision, ctl->buf, sizeof(ctl->buf));
       ctl->already_rendered = 1;
     }
   fprintf(fp, "%s ", ctl->buf);
 }
   
-
 /* va_list version of zlog. */
 static void
 vzlog (struct zlog *zl, int priority, const char *format, va_list args)
 {
+  LOCK
+  uvzlog(zl, priority, format, args);
+  UNLOCK
+}
+
+/* va_list version of zlog. Unprotected assumes mutex already held*/
+static void
+uvzlog (struct zlog *zl, int priority, const char *format, va_list args)
+{
   struct timestamp_control tsctl;
   tsctl.already_rendered = 0;
 
-  qpt_mutex_lock(mx);
+  assert(vty_lock_count);
 
   /* If zlog is not specified, use default one. */
   if (zl == NULL)
@@ -251,18 +256,11 @@ vzlog (struct zlog *zl, int priority, const char *format, va_list args)
       /* Terminal monitor. */
       if (priority <= zl->maxlvl[ZLOG_DEST_MONITOR])
         {
-          /* must be unlocked as vty handles it's own pthread stuff
-           * extract what we need from the zlog first
-           */
           const char *priority_name = (zl->record_priority ? zlog_priority[priority] : NULL);
           const char *proto_name = zlog_proto_names[zl->protocol];
-
-          qpt_mutex_unlock(mx);
           vty_log (priority_name, proto_name, format, &tsctl, args);
-          return;
         }
     }
-  qpt_mutex_unlock(mx);
 }
 
 static char *
@@ -567,8 +565,16 @@ zlog_backtrace_sigsafe(int priority, void *program_counter)
 void
 zlog_backtrace(int priority)
 {
+  LOCK
+  zlog_backtrace(priority);
+  UNLOCK
+}
+
+static void
+uzlog_backtrace(int priority)
+{
 #ifndef HAVE_GLIBC_BACKTRACE
-  zlog(NULL, priority, "No backtrace available on this platform.");
+  uzlog(NULL, priority, "No backtrace available on this platform.");
 #else
   void *array[20];
   int size, i;
@@ -577,27 +583,38 @@ zlog_backtrace(int priority)
   if (((size = backtrace(array,sizeof(array)/sizeof(array[0]))) <= 0) ||
       ((size_t)size > sizeof(array)/sizeof(array[0])))
     {
-      zlog_err("Cannot get backtrace, returned invalid # of frames %d "
+      uzlog(NULL, LOG_ERR, "Cannot get backtrace, returned invalid # of frames %d "
 	       "(valid range is between 1 and %lu)",
 	       size, (unsigned long)(sizeof(array)/sizeof(array[0])));
       return;
     }
-  zlog(NULL, priority, "Backtrace for %d stack frames:", size);
+  uzlog(NULL, priority, "Backtrace for %d stack frames:", size);
   if (!(strings = backtrace_symbols(array, size)))
     {
-      zlog_err("Cannot get backtrace symbols (out of memory?)");
+      uzlog(NULL, LOG_ERR, "Cannot get backtrace symbols (out of memory?)");
       for (i = 0; i < size; i++)
-	zlog(NULL, priority, "[bt %d] %p",i,array[i]);
+	uzlog(NULL, priority, "[bt %d] %p",i,array[i]);
     }
   else
     {
       for (i = 0; i < size; i++)
-	zlog(NULL, priority, "[bt %d] %s",i,strings[i]);
+	uzlog(NULL, priority, "[bt %d] %s",i,strings[i]);
       free(strings);
     }
 #endif /* HAVE_GLIBC_BACKTRACE */
 }
 
+/* unlocked version */
+void
+uzlog (struct zlog *zl, int priority, const char *format, ...)
+{
+  va_list args;
+
+  va_start(args, format);
+  uvzlog (zl, priority, format, args);
+  va_end (args);
+}
+
 void
 zlog (struct zlog *zl, int priority, const char *format, ...)
 {
@@ -705,15 +722,13 @@ static void
 zlog_abort (const char *mess)
 {
   /* Force fallback file logging? */
-  qpt_mutex_lock(mx);
   if (zlog_default && !zlog_default->fp &&
       ((logfile_fd = open_crashlog()) >= 0) &&
       ((zlog_default->fp = fdopen(logfile_fd, "w")) != NULL))
     zlog_default->maxlvl[ZLOG_DEST_FILE] = LOG_ERR;
-  qpt_mutex_unlock(mx);
 
-  zlog(NULL, LOG_CRIT, "%s", mess);
-  zlog_backtrace(LOG_CRIT);
+  uzlog(NULL, LOG_CRIT, "%s", mess);
+  uzlog_backtrace(LOG_CRIT);
   abort();
 }
 
@@ -747,7 +762,7 @@ openzlog (const char *progname, zlog_proto_t protocol,
 void
 closezlog (struct zlog *zl)
 {
-  qpt_mutex_lock(mx);
+  LOCK
 
   closelog();
 
@@ -756,14 +771,14 @@ closezlog (struct zlog *zl)
 
   XFREE (MTYPE_ZLOG, zl);
 
-  qpt_mutex_unlock(mx);
+  UNLOCK
 }
 
 /* Called from command.c. */
 void
 zlog_set_level (struct zlog *zl, zlog_dest_t dest, int log_level)
 {
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -773,7 +788,7 @@ zlog_set_level (struct zlog *zl, zlog_dest_t dest, int log_level)
       zl->maxlvl[dest] = log_level;
     }
 
-  qpt_mutex_unlock(mx);
+  UNLOCK
 }
 
 int
@@ -783,10 +798,10 @@ zlog_set_file (struct zlog *zl, const char *filename, int log_level)
   mode_t oldumask;
   int result = 1;
 
-  qpt_mutex_lock(mx);
+  LOCK
 
   /* There is opend file.  */
-  do_reset_file (zl);
+  uzlog_reset_file (zl);
 
   /* Set default zl. */
   if (zl == NULL)
@@ -810,7 +825,7 @@ zlog_set_file (struct zlog *zl, const char *filename, int log_level)
         }
     }
 
-  qpt_mutex_unlock(mx);
+  UNLOCK
   return result;
 }
 
@@ -819,14 +834,14 @@ int
 zlog_reset_file (struct zlog *zl)
 {
   int result;
-  qpt_mutex_lock(mx);
-  result = do_reset_file(zl);
-  qpt_mutex_unlock(mx);
+  LOCK
+  result = uzlog_reset_file(zl);
+  UNLOCK
   return result;
 }
 
 static int
-do_reset_file (struct zlog *zl)
+uzlog_reset_file (struct zlog *zl)
   {
   if (zl == NULL)
     zl = zlog_default;
@@ -852,8 +867,9 @@ int
 zlog_rotate (struct zlog *zl)
 {
   int level;
+  int result = 1;
 
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -880,11 +896,10 @@ zlog_rotate (struct zlog *zl)
             {
               /* can't call logging while locked */
               char *fname = strdup(zl->filename);
-              qpt_mutex_unlock(mx);
-              zlog_err("Log rotate failed: cannot open file %s for append: %s",
+              uzlog(NULL, LOG_ERR, "Log rotate failed: cannot open file %s for append: %s",
 	  	   fname, safe_strerror(save_errno));
               free(fname);
-              return -1;
+              result = -1;
             }
           else
             {
@@ -893,8 +908,8 @@ zlog_rotate (struct zlog *zl)
             }
         }
     }
-  qpt_mutex_unlock(mx);
-  return 1;
+  UNLOCK
+  return result;
 }
 
 int
@@ -902,7 +917,7 @@ zlog_get_default_lvl (struct zlog *zl)
 {
   int result = LOG_DEBUG;
 
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -912,14 +927,14 @@ zlog_get_default_lvl (struct zlog *zl)
       result = zl->default_lvl;
     }
 
-  qpt_mutex_unlock(mx);
+  UNLOCK
   return result;
 }
 
 void
 zlog_set_default_lvl (struct zlog *zl, int level)
 {
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -929,7 +944,7 @@ zlog_set_default_lvl (struct zlog *zl, int level)
       zl->default_lvl = level;
     }
 
-  qpt_mutex_unlock(mx);
+  UNLOCK
 }
 
 /* Set logging level and default for all destinations */
@@ -938,7 +953,7 @@ zlog_set_default_lvl_dest (struct zlog *zl, int level)
 {
   int i;
 
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -952,7 +967,7 @@ zlog_set_default_lvl_dest (struct zlog *zl, int level)
           zl->maxlvl[i] = level;
     }
 
- qpt_mutex_unlock(mx);
+  UNLOCK
 }
 
 int
@@ -960,7 +975,7 @@ zlog_get_maxlvl (struct zlog *zl, zlog_dest_t dest)
 {
   int result = ZLOG_DISABLED;
 
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -970,7 +985,7 @@ zlog_get_maxlvl (struct zlog *zl, zlog_dest_t dest)
       result = zl->maxlvl[dest];
     }
 
-  qpt_mutex_unlock(mx);
+  UNLOCK
   return result;
 }
 
@@ -979,7 +994,7 @@ zlog_get_facility (struct zlog *zl)
 {
   int result = LOG_DAEMON;
 
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -989,14 +1004,14 @@ zlog_get_facility (struct zlog *zl)
       result = zl->facility;
     }
 
-  qpt_mutex_unlock(mx);
+  UNLOCK
   return result;
 }
 
 void
 zlog_set_facility (struct zlog *zl, int facility)
 {
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -1006,7 +1021,7 @@ zlog_set_facility (struct zlog *zl, int facility)
       zl->facility = facility;
     }
 
-  qpt_mutex_unlock(mx);
+  UNLOCK
 }
 
 int
@@ -1014,7 +1029,7 @@ zlog_get_record_priority (struct zlog *zl)
 {
   int result = 0;
 
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -1024,14 +1039,14 @@ zlog_get_record_priority (struct zlog *zl)
       result = zl->record_priority;
     }
 
-  qpt_mutex_unlock(mx);
+  UNLOCK
   return result;
 }
 
 void
 zlog_set_record_priority (struct zlog *zl, int record_priority)
 {
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -1040,7 +1055,7 @@ zlog_set_record_priority (struct zlog *zl, int record_priority)
     {
       zl->record_priority = record_priority;
     }
-  qpt_mutex_unlock(mx);
+  UNLOCK
 }
 
 int
@@ -1048,7 +1063,7 @@ zlog_get_timestamp_precision (struct zlog *zl)
 {
   int result = 0;
 
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -1057,14 +1072,14 @@ zlog_get_timestamp_precision (struct zlog *zl)
     {
       result = zl->timestamp_precision;
     }
-  qpt_mutex_unlock(mx);
+  UNLOCK
   return result;
 }
 
 void
 zlog_set_timestamp_precision (struct zlog *zl, int timestamp_precision)
 {
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -1074,16 +1089,25 @@ zlog_set_timestamp_precision (struct zlog *zl, int timestamp_precision)
       zl->timestamp_precision = timestamp_precision;
     }
 
-  qpt_mutex_unlock(mx);
+  UNLOCK
 }
 
 /* returns name of ZLOG_NONE if no zlog given and no default set */
 const char *
 zlog_get_proto_name (struct zlog *zl)
 {
-  zlog_proto_t protocol = ZLOG_NONE;
+  const char * result;
+  LOCK
+  result = uzlog_get_proto_name(zl);
+  UNLOCK
+  return result;
+}
 
-  qpt_mutex_lock(mx);
+/* unprotected version, assumes mutex held */
+const char *
+uzlog_get_proto_name (struct zlog *zl)
+{
+  zlog_proto_t protocol = ZLOG_NONE;
 
   if (zl == NULL)
     zl = zlog_default;
@@ -1093,7 +1117,6 @@ zlog_get_proto_name (struct zlog *zl)
       protocol = zl->protocol;
     }
 
-  qpt_mutex_unlock(mx);
   return zlog_proto_names[protocol];
 }
 
@@ -1103,7 +1126,7 @@ zlog_get_filename (struct zlog *zl)
 {
   char * result = NULL;
 
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -1113,7 +1136,7 @@ zlog_get_filename (struct zlog *zl)
       result = strdup(zl->filename);
     }
 
-  qpt_mutex_unlock(mx);
+  UNLOCK
   return result;
 }
 
@@ -1122,7 +1145,7 @@ zlog_get_ident (struct zlog *zl)
 {
   const char * result = NULL;
 
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -1132,7 +1155,7 @@ zlog_get_ident (struct zlog *zl)
       result = zl->ident;
     }
 
-  qpt_mutex_unlock(mx);
+  UNLOCK
   return result;
 }
 
@@ -1142,7 +1165,7 @@ zlog_is_file (struct zlog *zl)
 {
   int result = 0;
 
-  qpt_mutex_lock(mx);
+  LOCK
 
   if (zl == NULL)
     zl = zlog_default;
@@ -1152,7 +1175,7 @@ zlog_is_file (struct zlog *zl)
       result = (zl->fp != NULL);
     }
 
-  qpt_mutex_unlock(mx);
+  UNLOCK;
   return result;
 }
 
@@ -1331,3 +1354,6 @@ proto_name2num(const char *s)
    return -1;
 }
 #undef RTSIZE
+
+#undef LOCK
+#undef UNLOCK
diff --git a/lib/log.h b/lib/log.h
index ec090ecf..6ab1b37c 100644
--- a/lib/log.h
+++ b/lib/log.h
@@ -117,6 +117,9 @@ extern void closezlog (struct zlog *zl);
 /* Generic function for zlog. */
 extern void zlog (struct zlog *zl, int priority, const char *format, ...)
   PRINTF_ATTRIBUTE(3, 4);
+/* assumed locked version for close friends */
+extern void uzlog (struct zlog *zl, int priority, const char *format, ...)
+  PRINTF_ATTRIBUTE(3, 4);
 
 /* Handy zlog functions. */
 extern void zlog_err (const char *format, ...) PRINTF_ATTRIBUTE(1, 2);
@@ -166,6 +169,7 @@ extern const char * zlog_get_ident (struct zlog *zl);
 extern char * zlog_get_filename (struct zlog *zl);
 extern int zlog_is_file (struct zlog *zl);
 extern const char * zlog_get_proto_name (struct zlog *zl);
+extern const char * uzlog_get_proto_name (struct zlog *zl);
 
 /* For hackey massage lookup and check */
 #define LOOKUP(x, y) mes_lookup(x, x ## _max, y, "(no item found)")
@@ -205,7 +209,9 @@ extern void zlog_backtrace_sigsafe(int priority, void *program_counter);
    *buf will be set to '\0', and 0 will be returned. */
 extern size_t quagga_timestamp(int timestamp_precision /* # subsecond digits */,
 			       char *buf, size_t buflen);
-
+/* unprotected version for when mutex already held */
+extern size_t uquagga_timestamp(int timestamp_precision /* # subsecond digits */,
+                               char *buf, size_t buflen);
 /* structure useful for avoiding repeated rendering of the same timestamp */
 struct timestamp_control {
    size_t len;		/* length of rendered timestamp */
diff --git a/lib/vty.c b/lib/vty.c
index 7ed2dba7..b062d0aa 100644
--- a/lib/vty.c
+++ b/lib/vty.c
@@ -38,6 +38,33 @@
 #include "network.h"
 
 #include <arpa/telnet.h>
+#include "qpthreads.h"
+
+/* Needs to be qpthread safe */
+qpt_mutex_t* vty_mutex = NULL;
+#ifdef NDEBUG
+#define LOCK qpt_mutex_lock(vty_mutex);
+#define UNLOCK qpt_mutex_unlock(vty_mutex);
+#else
+int vty_lock_count = 0;
+#define LOCK qpt_mutex_lock(vty_mutex);++vty_lock_count;
+#define UNLOCK --vty_lock_count;qpt_mutex_unlock(vty_mutex);
+#endif
+
+/*
+ * To make vty qpthread safe we use a single mutex.  In general external
+ * routines have explicit locks, static routines assume that they are being
+ * called with the mutex already locked.  There are a few exceptions, e.g.
+ * callbacks where static routines are being invoked from outside the module.
+ *
+ * As we are not using recursive mutexes so there are a few cases where
+ * both external and static versions of a routine exist.  The former for use
+ * outside, the latter for use inside the module (and lock).  In these cases
+ * the internal static versions starts uty_.
+ *
+ * vty and log recurse through each other, so the same mutex is used
+ * for both, i.e. they are treated as being part of the same monitor.
+ */
 
 /* Vty events */
 enum event
@@ -53,7 +80,14 @@ enum event
 #endif /* VTYSH */
 };
 
+/* Prototypes */
+static int uty_out (struct vty *vty, const char *format, ...);
+static int uty_vout(struct vty *vty, const char *format, va_list args);
 static void vty_event (enum event, int, struct vty *);
+static void uty_hello (struct vty *vty);
+static void uty_close (struct vty *vty);
+static int uty_config_unlock (struct vty *vty);
+static int uty_shell (struct vty *vty);
 
 /* Extern host structure from command.c */
 extern struct host host;
@@ -89,29 +123,56 @@ static u_char restricted_mode = 0;
 /* Integrated configuration file path */
 char integrate_default[] = SYSCONFDIR INTEGRATE_DEFAULT_CONFIG;
 
-
 /* VTY standard output function.   vty == NULL or VTY_SHELL => stdout	*/
 int
 vty_out (struct vty *vty, const char *format, ...)
 {
+  int result;
+
+  LOCK
   va_list args;
+  va_start (args, format);
+  result = uty_vout(vty, format, args);
+  va_end (args);
+  UNLOCK
+  return result;
+}
+
+/* internal VTY standard output function.   vty == NULL or VTY_SHELL => stdout   */
+static int
+uty_out (struct vty *vty, const char *format, ...)
+{
+  int result;
+  assert(vty_lock_count);
+  va_list args;
+  va_start (args, format);
+  result = uty_vout(vty, format, args);
+  va_end (args);
+  return result;
+}
+
+/* internal VTY standard output function.   vty == NULL or VTY_SHELL => stdout   */
+static int
+uty_vout(struct vty *vty, const char *format, va_list args)
+{
   int len = 0;
   int size = 1024;
   char buf[1024];
   char *p = NULL;
+  va_list ac;
+
+  assert(vty_lock_count);
 
-  if (vty_shell (vty))
+  if (uty_shell (vty))
     {
-      va_start (args, format);
       vprintf (format, args);
-      va_end (args);
     }
   else
     {
       /* Try to write to initial buffer.  */
-      va_start (args, format);
-      len = vsnprintf (buf, sizeof buf, format, args);
-      va_end (args);
+      va_copy(ac, args);
+      len = vsnprintf (buf, sizeof buf, format, ac);
+      va_end(ac);
 
       /* Initial buffer is not enough.  */
       if (len < 0 || len >= size)
@@ -125,11 +186,11 @@ vty_out (struct vty *vty, const char *format, ...)
 
 	      p = XREALLOC (MTYPE_VTY_OUT_BUF, p, size);
 	      if (! p)
-		return -1;
+                  return -1;
 
-	      va_start (args, format);
-	      len = vsnprintf (p, size, format, args);
-	      va_end (args);
+	      va_copy(ac, args);
+	      len = vsnprintf (p, size, format, ac);
+	      va_end(ac);
 
 	      if (len > -1 && len < size)
 		break;
@@ -180,9 +241,11 @@ vty_log_out (struct vty *vty, const char *level, const char *proto_str,
   int len;
   char buf[1024];
 
+  assert(vty_lock_count);
+
   if (!ctl->already_rendered)
     {
-      ctl->len = quagga_timestamp(ctl->precision, ctl->buf, sizeof(ctl->buf));
+      ctl->len = uquagga_timestamp(ctl->precision, ctl->buf, sizeof(ctl->buf));
       ctl->already_rendered = 1;
     }
   if (ctl->len+1 >= sizeof(buf))
@@ -213,7 +276,7 @@ vty_log_out (struct vty *vty, const char *level, const char *proto_str,
 	return -1;
       /* Fatal I/O error. */
       vty->monitor = 0; /* disable monitoring to avoid infinite recursion */
-      zlog_warn("%s: write failed to vty client fd %d, closing: %s",
+      uzlog(NULL, LOG_WARNING, "%s: write failed to vty client fd %d, closing: %s",
 		__func__, vty->fd, safe_strerror(errno));
       buffer_reset(vty->obuf);
       /* cannot call vty_close, because a parent routine may still try
@@ -248,6 +311,15 @@ vty_time_print (struct vty *vty, int cr)
 void
 vty_hello (struct vty *vty)
 {
+  LOCK
+  uty_hello(vty);
+  UNLOCK
+}
+
+static void
+uty_hello (struct vty *vty)
+{
+  assert(vty_lock_count);
   if (host.motdfile)
     {
       FILE *f;
@@ -263,15 +335,15 @@ vty_hello (struct vty *vty)
 	      for (s = buf + strlen (buf); (s > buf) && isspace ((int)*(s - 1));
 		   s--);
 	      *s = '\0';
-	      vty_out (vty, "%s%s", buf, VTY_NEWLINE);
+	      uty_out (vty, "%s%s", buf, VTY_NEWLINE);
 	    }
 	  fclose (f);
 	}
       else
-	vty_out (vty, "MOTD file not found%s", VTY_NEWLINE);
+	uty_out (vty, "MOTD file not found%s", VTY_NEWLINE);
     }
   else if (host.motd)
-    vty_out (vty, host.motd);
+    uty_out (vty, "%s", host.motd);
 }
 
 /* Put out prompt and wait input from user. */
@@ -281,6 +353,8 @@ vty_prompt (struct vty *vty)
   struct utsname names;
   const char*hostname;
 
+  assert(vty_lock_count);
+
   if (vty->type == VTY_TERM)
     {
       hostname = host.name;
@@ -289,7 +363,7 @@ vty_prompt (struct vty *vty)
 	  uname (&names);
 	  hostname = names.nodename;
 	}
-      vty_out (vty, cmd_prompt (vty->node), hostname);
+      uty_out (vty, cmd_prompt (vty->node), hostname);
     }
 }
 
@@ -298,7 +372,8 @@ static void
 vty_will_echo (struct vty *vty)
 {
   unsigned char cmd[] = { IAC, WILL, TELOPT_ECHO, '\0' };
-  vty_out (vty, "%s", cmd);
+  assert(vty_lock_count);
+  uty_out (vty, "%s", cmd);
 }
 
 /* Make suppress Go-Ahead telnet option. */
@@ -306,7 +381,8 @@ static void
 vty_will_suppress_go_ahead (struct vty *vty)
 {
   unsigned char cmd[] = { IAC, WILL, TELOPT_SGA, '\0' };
-  vty_out (vty, "%s", cmd);
+  assert(vty_lock_count);
+  uty_out (vty, "%s", cmd);
 }
 
 /* Make don't use linemode over telnet. */
@@ -314,7 +390,8 @@ static void
 vty_dont_linemode (struct vty *vty)
 {
   unsigned char cmd[] = { IAC, DONT, TELOPT_LINEMODE, '\0' };
-  vty_out (vty, "%s", cmd);
+  assert(vty_lock_count);
+  uty_out (vty, "%s", cmd);
 }
 
 /* Use window size. */
@@ -322,7 +399,8 @@ static void
 vty_do_window_size (struct vty *vty)
 {
   unsigned char cmd[] = { IAC, DO, TELOPT_NAWS, '\0' };
-  vty_out (vty, "%s", cmd);
+  assert(vty_lock_count);
+  uty_out (vty, "%s", cmd);
 }
 
 #if 0 /* Currently not used. */
@@ -331,7 +409,8 @@ static void
 vty_dont_lflow_ahead (struct vty *vty)
 {
   unsigned char cmd[] = { IAC, DONT, TELOPT_LFLOW, '\0' };
-  vty_out (vty, "%s", cmd);
+  assert(vty_lock_count);
+  uty_out (vty, "%s", cmd);
 }
 #endif /* 0 */
 
@@ -357,6 +436,8 @@ vty_auth (struct vty *vty, char *buf)
   int fail;
   char *crypt (const char *, const char *);
 
+  assert(vty_lock_count);
+
   switch (vty->node)
     {
     case AUTH_NODE:
@@ -400,14 +481,14 @@ vty_auth (struct vty *vty, char *buf)
 	{
 	  if (vty->node == AUTH_NODE)
 	    {
-	      vty_out (vty, "%% Bad passwords, too many failures!%s", VTY_NEWLINE);
+	      uty_out (vty, "%% Bad passwords, too many failures!%s", VTY_NEWLINE);
 	      vty->status = VTY_CLOSE;
 	    }
 	  else
 	    {
 	      /* AUTH_ENABLE_NODE */
 	      vty->fail = 0;
-	      vty_out (vty, "%% Bad enable passwords, too many failures!%s", VTY_NEWLINE);
+	      uty_out (vty, "%% Bad enable passwords, too many failures!%s", VTY_NEWLINE);
 	      vty->node = restricted_mode ? RESTRICTED_NODE : VIEW_NODE;
 	    }
 	}
@@ -422,6 +503,8 @@ vty_command (struct vty *vty, char *buf)
   vector vline;
   const char *protocolname;
 
+  assert(vty_lock_count);
+
   /* Split readline string up into the vector */
   vline = cmd_make_strvec (buf);
 
@@ -437,17 +520,19 @@ vty_command (struct vty *vty, char *buf)
     GETRUSAGE(&before);
 #endif /* CONSUMED_TIME_CHECK */
 
+  UNLOCK
   ret = cmd_execute_command (vline, vty, NULL, 0);
+  LOCK
 
   /* Get the name of the protocol if any */
-  protocolname = zlog_get_proto_name(NULL);
+  protocolname = uzlog_get_proto_name(NULL);
 
 #ifdef CONSUMED_TIME_CHECK
     GETRUSAGE(&after);
     if ((realtime = thread_consumed_time(&after, &before, &cputime)) >
     	CONSUMED_TIME_CHECK)
       /* Warn about CPU hog that must be fixed. */
-      zlog_warn("SLOW COMMAND: command took %lums (cpu time %lums): %s",
+      uzlog(NULL, LOG_WARNING, "SLOW COMMAND: command took %lums (cpu time %lums): %s",
       		realtime/1000, cputime/1000, buf);
   }
 #endif /* CONSUMED_TIME_CHECK */
@@ -457,16 +542,16 @@ vty_command (struct vty *vty, char *buf)
       {
       case CMD_WARNING:
 	if (vty->type == VTY_FILE)
-	  vty_out (vty, "Warning...%s", VTY_NEWLINE);
+	  uty_out (vty, "Warning...%s", VTY_NEWLINE);
 	break;
       case CMD_ERR_AMBIGUOUS:
-	vty_out (vty, "%% Ambiguous command.%s", VTY_NEWLINE);
+	uty_out (vty, "%% Ambiguous command.%s", VTY_NEWLINE);
 	break;
       case CMD_ERR_NO_MATCH:
-	vty_out (vty, "%% [%s] Unknown command: %s%s", protocolname, buf, VTY_NEWLINE);
+	uty_out (vty, "%% [%s] Unknown command: %s%s", protocolname, buf, VTY_NEWLINE);
 	break;
       case CMD_ERR_INCOMPLETE:
-	vty_out (vty, "%% Command incomplete.%s", VTY_NEWLINE);
+	uty_out (vty, "%% Command incomplete.%s", VTY_NEWLINE);
 	break;
       }
   cmd_free_strvec (vline);
@@ -481,6 +566,7 @@ static const char telnet_space_char = ' ';
 static void
 vty_write (struct vty *vty, const char *buf, size_t nbytes)
 {
+  assert(vty_lock_count);
   if ((vty->node == AUTH_NODE) || (vty->node == AUTH_ENABLE_NODE))
     return;
 
@@ -492,6 +578,7 @@ vty_write (struct vty *vty, const char *buf, size_t nbytes)
 static void
 vty_ensure (struct vty *vty, int length)
 {
+  assert(vty_lock_count);
   if (vty->max <= length)
     {
       vty->max *= 2;
@@ -506,6 +593,8 @@ vty_self_insert (struct vty *vty, char c)
   int i;
   int length;
 
+  assert(vty_lock_count);
+
   vty_ensure (vty, vty->length + 1);
   length = vty->length - vty->cp;
   memmove (&vty->buf[vty->cp + 1], &vty->buf[vty->cp], length);
@@ -523,6 +612,7 @@ vty_self_insert (struct vty *vty, char c)
 static void
 vty_self_insert_overwrite (struct vty *vty, char c)
 {
+  assert(vty_lock_count);
   vty_ensure (vty, vty->length + 1);
   vty->buf[vty->cp++] = c;
 
@@ -539,7 +629,11 @@ vty_self_insert_overwrite (struct vty *vty, char c)
 static void
 vty_insert_word_overwrite (struct vty *vty, char *str)
 {
+
   int len = strlen (str);
+
+  assert(vty_lock_count);
+
   vty_write (vty, str, len);
   strcpy (&vty->buf[vty->cp], str);
   vty->cp += len;
@@ -550,6 +644,7 @@ vty_insert_word_overwrite (struct vty *vty, char *str)
 static void
 vty_forward_char (struct vty *vty)
 {
+  assert(vty_lock_count);
   if (vty->cp < vty->length)
     {
       vty_write (vty, &vty->buf[vty->cp], 1);
@@ -561,6 +656,7 @@ vty_forward_char (struct vty *vty)
 static void
 vty_backward_char (struct vty *vty)
 {
+  assert(vty_lock_count);
   if (vty->cp > 0)
     {
       vty->cp--;
@@ -572,6 +668,7 @@ vty_backward_char (struct vty *vty)
 static void
 vty_beginning_of_line (struct vty *vty)
 {
+  assert(vty_lock_count);
   while (vty->cp)
     vty_backward_char (vty);
 }
@@ -580,6 +677,7 @@ vty_beginning_of_line (struct vty *vty)
 static void
 vty_end_of_line (struct vty *vty)
 {
+  assert(vty_lock_count);
   while (vty->cp < vty->length)
     vty_forward_char (vty);
 }
@@ -594,6 +692,8 @@ vty_history_print (struct vty *vty)
 {
   int length;
 
+  assert(vty_lock_count);
+
   vty_kill_line_from_beginning (vty);
 
   /* Get previous line from history buffer */
@@ -611,6 +711,8 @@ vty_next_line (struct vty *vty)
 {
   int try_index;
 
+  assert(vty_lock_count);
+
   if (vty->hp == vty->hindex)
     return;
 
@@ -636,6 +738,8 @@ vty_previous_line (struct vty *vty)
 {
   int try_index;
 
+  assert(vty_lock_count);
+
   try_index = vty->hp;
   if (try_index == 0)
     try_index = VTY_MAXHIST - 1;
@@ -654,6 +758,7 @@ vty_previous_line (struct vty *vty)
 static void
 vty_redraw_line (struct vty *vty)
 {
+  assert(vty_lock_count);
   vty_write (vty, vty->buf, vty->length);
   vty->cp = vty->length;
 }
@@ -662,6 +767,7 @@ vty_redraw_line (struct vty *vty)
 static void
 vty_forward_word (struct vty *vty)
 {
+  assert(vty_lock_count);
   while (vty->cp != vty->length && vty->buf[vty->cp] != ' ')
     vty_forward_char (vty);
 
@@ -673,6 +779,7 @@ vty_forward_word (struct vty *vty)
 static void
 vty_backward_pure_word (struct vty *vty)
 {
+  assert(vty_lock_count);
   while (vty->cp > 0 && vty->buf[vty->cp - 1] != ' ')
     vty_backward_char (vty);
 }
@@ -681,6 +788,7 @@ vty_backward_pure_word (struct vty *vty)
 static void
 vty_backward_word (struct vty *vty)
 {
+  assert(vty_lock_count);
   while (vty->cp > 0 && vty->buf[vty->cp - 1] == ' ')
     vty_backward_char (vty);
 
@@ -693,7 +801,8 @@ vty_backward_word (struct vty *vty)
 static void
 vty_down_level (struct vty *vty)
 {
-  vty_out (vty, "%s", VTY_NEWLINE);
+  assert(vty_lock_count);
+  uty_out (vty, "%s", VTY_NEWLINE);
   (*config_exit_cmd.func)(NULL, vty, 0, NULL);
   vty_prompt (vty);
   vty->cp = 0;
@@ -703,7 +812,8 @@ vty_down_level (struct vty *vty)
 static void
 vty_end_config (struct vty *vty)
 {
-  vty_out (vty, "%s", VTY_NEWLINE);
+  assert(vty_lock_count);
+  uty_out (vty, "%s", VTY_NEWLINE);
 
   switch (vty->node)
     {
@@ -731,7 +841,7 @@ vty_end_config (struct vty *vty)
     case KEYCHAIN_KEY_NODE:
     case MASC_NODE:
     case VTY_NODE:
-      vty_config_unlock (vty);
+      uty_config_unlock (vty);
       vty->node = ENABLE_NODE;
       break;
     default:
@@ -750,6 +860,8 @@ vty_delete_char (struct vty *vty)
   int i;
   int size;
 
+  assert(vty_lock_count);
+
   if (vty->length == 0)
     {
       vty_down_level (vty);
@@ -779,6 +891,7 @@ vty_delete_char (struct vty *vty)
 static void
 vty_delete_backward_char (struct vty *vty)
 {
+  assert(vty_lock_count);
   if (vty->cp == 0)
     return;
 
@@ -793,6 +906,8 @@ vty_kill_line (struct vty *vty)
   int i;
   int size;
 
+  assert(vty_lock_count);
+
   size = vty->length - vty->cp;
 
   if (size == 0)
@@ -811,6 +926,7 @@ vty_kill_line (struct vty *vty)
 static void
 vty_kill_line_from_beginning (struct vty *vty)
 {
+  assert(vty_lock_count);
   vty_beginning_of_line (vty);
   vty_kill_line (vty);
 }
@@ -819,6 +935,7 @@ vty_kill_line_from_beginning (struct vty *vty)
 static void
 vty_forward_kill_word (struct vty *vty)
 {
+  assert(vty_lock_count);
   while (vty->cp != vty->length && vty->buf[vty->cp] == ' ')
     vty_delete_char (vty);
   while (vty->cp != vty->length && vty->buf[vty->cp] != ' ')
@@ -829,6 +946,7 @@ vty_forward_kill_word (struct vty *vty)
 static void
 vty_backward_kill_word (struct vty *vty)
 {
+  assert(vty_lock_count);
   while (vty->cp > 0 && vty->buf[vty->cp - 1] == ' ')
     vty_delete_backward_char (vty);
   while (vty->cp > 0 && vty->buf[vty->cp - 1] != ' ')
@@ -841,6 +959,8 @@ vty_transpose_chars (struct vty *vty)
 {
   char c1, c2;
 
+  assert(vty_lock_count);
+
   /* If length is short or point is near by the beginning of line then
      return. */
   if (vty->length < 2 || vty->cp < 1)
@@ -872,11 +992,14 @@ vty_transpose_chars (struct vty *vty)
 static void
 vty_complete_command (struct vty *vty)
 {
+
   int i;
   int ret;
   char **matched = NULL;
   vector vline;
 
+  assert(vty_lock_count);
+
   if (vty->node == AUTH_NODE || vty->node == AUTH_ENABLE_NODE)
     return;
 
@@ -892,11 +1015,11 @@ vty_complete_command (struct vty *vty)
 
   cmd_free_strvec (vline);
 
-  vty_out (vty, "%s", VTY_NEWLINE);
+  uty_out (vty, "%s", VTY_NEWLINE);
   switch (ret)
     {
     case CMD_ERR_AMBIGUOUS:
-      vty_out (vty, "%% Ambiguous command.%s", VTY_NEWLINE);
+      uty_out (vty, "%% Ambiguous command.%s", VTY_NEWLINE);
       vty_prompt (vty);
       vty_redraw_line (vty);
       break;
@@ -926,11 +1049,11 @@ vty_complete_command (struct vty *vty)
       for (i = 0; matched[i] != NULL; i++)
 	{
 	  if (i != 0 && ((i % 6) == 0))
-	    vty_out (vty, "%s", VTY_NEWLINE);
-	  vty_out (vty, "%-10s ", matched[i]);
+	    uty_out (vty, "%s", VTY_NEWLINE);
+	  uty_out (vty, "%-10s ", matched[i]);
 	  XFREE (MTYPE_TMP, matched[i]);
 	}
-      vty_out (vty, "%s", VTY_NEWLINE);
+      uty_out (vty, "%s", VTY_NEWLINE);
 
       vty_prompt (vty);
       vty_redraw_line (vty);
@@ -954,11 +1077,13 @@ vty_describe_fold (struct vty *vty, int cmd_width,
   const char *cmd, *p;
   int pos;
 
+  assert(vty_lock_count);
+
   cmd = desc->cmd[0] == '.' ? desc->cmd + 1 : desc->cmd;
 
   if (desc_width <= 0)
     {
-      vty_out (vty, "  %-*s  %s%s", cmd_width, cmd, desc->str, VTY_NEWLINE);
+      uty_out (vty, "  %-*s  %s%s", cmd_width, cmd, desc->str, VTY_NEWLINE);
       return;
     }
 
@@ -975,12 +1100,12 @@ vty_describe_fold (struct vty *vty, int cmd_width,
 
       strncpy (buf, p, pos);
       buf[pos] = '\0';
-      vty_out (vty, "  %-*s  %s%s", cmd_width, cmd, buf, VTY_NEWLINE);
+      uty_out (vty, "  %-*s  %s%s", cmd_width, cmd, buf, VTY_NEWLINE);
 
       cmd = "";
     }
 
-  vty_out (vty, "  %-*s  %s%s", cmd_width, cmd, p, VTY_NEWLINE);
+  uty_out (vty, "  %-*s  %s%s", cmd_width, cmd, p, VTY_NEWLINE);
 
   XFREE (MTYPE_TMP, buf);
 }
@@ -989,12 +1114,14 @@ vty_describe_fold (struct vty *vty, int cmd_width,
 static void
 vty_describe_command (struct vty *vty)
 {
-  int ret;
+   int ret;
   vector vline;
   vector describe;
   unsigned int i, width, desc_width;
   struct desc *desc, *desc_cr = NULL;
 
+  assert(vty_lock_count);
+
   vline = cmd_make_strvec (vty->buf);
 
   /* In case of '> ?'. */
@@ -1009,17 +1136,17 @@ vty_describe_command (struct vty *vty)
 
   describe = cmd_describe_command (vline, vty, &ret);
 
-  vty_out (vty, "%s", VTY_NEWLINE);
+  uty_out (vty, "%s", VTY_NEWLINE);
 
   /* Ambiguous error. */
   switch (ret)
     {
     case CMD_ERR_AMBIGUOUS:
-      vty_out (vty, "%% Ambiguous command.%s", VTY_NEWLINE);
+      uty_out (vty, "%% Ambiguous command.%s", VTY_NEWLINE);
       goto out;
       break;
     case CMD_ERR_NO_MATCH:
-      vty_out (vty, "%% There is no matched command.%s", VTY_NEWLINE);
+      uty_out (vty, "%% There is no matched command.%s", VTY_NEWLINE);
       goto out;
       break;
     }
@@ -1059,18 +1186,18 @@ vty_describe_command (struct vty *vty)
 	  }
 
 	if (!desc->str)
-	  vty_out (vty, "  %-s%s",
+	  uty_out (vty, "  %-s%s",
 		   desc->cmd[0] == '.' ? desc->cmd + 1 : desc->cmd,
 		   VTY_NEWLINE);
 	else if (desc_width >= strlen (desc->str))
-	  vty_out (vty, "  %-*s  %s%s", width,
+	  uty_out (vty, "  %-*s  %s%s", width,
 		   desc->cmd[0] == '.' ? desc->cmd + 1 : desc->cmd,
 		   desc->str, VTY_NEWLINE);
 	else
 	  vty_describe_fold (vty, width, desc_width, desc);
 
 #if 0
-	vty_out (vty, "  %-*s %s%s", width
+	uty_out (vty, "  %-*s %s%s", width
 		 desc->cmd[0] == '.' ? desc->cmd + 1 : desc->cmd,
 		 desc->str ? desc->str : "", VTY_NEWLINE);
 #endif /* 0 */
@@ -1079,11 +1206,11 @@ vty_describe_command (struct vty *vty)
   if ((desc = desc_cr))
     {
       if (!desc->str)
-	vty_out (vty, "  %-s%s",
+	uty_out (vty, "  %-s%s",
 		 desc->cmd[0] == '.' ? desc->cmd + 1 : desc->cmd,
 		 VTY_NEWLINE);
       else if (desc_width >= strlen (desc->str))
-	vty_out (vty, "  %-*s  %s%s", width,
+	uty_out (vty, "  %-*s  %s%s", width,
 		 desc->cmd[0] == '.' ? desc->cmd + 1 : desc->cmd,
 		 desc->str, VTY_NEWLINE);
       else
@@ -1102,6 +1229,7 @@ out:
 static void
 vty_clear_buf (struct vty *vty)
 {
+  assert(vty_lock_count);
   memset (vty->buf, 0, vty->max);
 }
 
@@ -1109,9 +1237,10 @@ vty_clear_buf (struct vty *vty)
 static void
 vty_stop_input (struct vty *vty)
 {
+  assert(vty_lock_count);
   vty->cp = vty->length = 0;
   vty_clear_buf (vty);
-  vty_out (vty, "%s", VTY_NEWLINE);
+  uty_out (vty, "%s", VTY_NEWLINE);
 
   switch (vty->node)
     {
@@ -1134,7 +1263,7 @@ vty_stop_input (struct vty *vty)
     case KEYCHAIN_KEY_NODE:
     case MASC_NODE:
     case VTY_NODE:
-      vty_config_unlock (vty);
+      uty_config_unlock (vty);
       vty->node = ENABLE_NODE;
       break;
     default:
@@ -1153,6 +1282,8 @@ vty_hist_add (struct vty *vty)
 {
   int index;
 
+  assert(vty_lock_count);
+
   if (vty->length == 0)
     return;
 
@@ -1188,46 +1319,48 @@ vty_telnet_option (struct vty *vty, unsigned char *buf, int nbytes)
 #ifdef TELNET_OPTION_DEBUG
   int i;
 
+  assert(vty_lock_count);
+
   for (i = 0; i < nbytes; i++)
     {
       switch (buf[i])
 	{
 	case IAC:
-	  vty_out (vty, "IAC ");
+	  uty_out (vty, "IAC ");
 	  break;
 	case WILL:
-	  vty_out (vty, "WILL ");
+	  uty_out (vty, "WILL ");
 	  break;
 	case WONT:
-	  vty_out (vty, "WONT ");
+	  uty_out (vty, "WONT ");
 	  break;
 	case DO:
-	  vty_out (vty, "DO ");
+	  uty_out (vty, "DO ");
 	  break;
 	case DONT:
-	  vty_out (vty, "DONT ");
+	  uty_out (vty, "DONT ");
 	  break;
 	case SB:
-	  vty_out (vty, "SB ");
+	  uty_out (vty, "SB ");
 	  break;
 	case SE:
-	  vty_out (vty, "SE ");
+	  uty_out (vty, "SE ");
 	  break;
 	case TELOPT_ECHO:
-	  vty_out (vty, "TELOPT_ECHO %s", VTY_NEWLINE);
+	  uty_out (vty, "TELOPT_ECHO %s", VTY_NEWLINE);
 	  break;
 	case TELOPT_SGA:
-	  vty_out (vty, "TELOPT_SGA %s", VTY_NEWLINE);
+	  uty_out (vty, "TELOPT_SGA %s", VTY_NEWLINE);
 	  break;
 	case TELOPT_NAWS:
-	  vty_out (vty, "TELOPT_NAWS %s", VTY_NEWLINE);
+	  uty_out (vty, "TELOPT_NAWS %s", VTY_NEWLINE);
 	  break;
 	default:
-	  vty_out (vty, "%x ", buf[i]);
+	  uty_out (vty, "%x ", buf[i]);
 	  break;
 	}
     }
-  vty_out (vty, "%s", VTY_NEWLINE);
+  uty_out (vty, "%s", VTY_NEWLINE);
 
 #endif /* TELNET_OPTION_DEBUG */
 
@@ -1252,11 +1385,11 @@ vty_telnet_option (struct vty *vty, unsigned char *buf, int nbytes)
 	  {
 	  case TELOPT_NAWS:
 	    if (vty->sb_len != TELNET_NAWS_SB_LEN)
-	      zlog_warn("RFC 1073 violation detected: telnet NAWS option "
+	      uzlog(NULL, LOG_WARNING, "RFC 1073 violation detected: telnet NAWS option "
 			"should send %d characters, but we received %lu",
 			TELNET_NAWS_SB_LEN, (u_long)vty->sb_len);
 	    else if (sizeof(vty->sb_buf) < TELNET_NAWS_SB_LEN)
-	      zlog_err("Bug detected: sizeof(vty->sb_buf) %lu < %d, "
+	      uzlog(NULL, LOG_ERR, "Bug detected: sizeof(vty->sb_buf) %lu < %d, "
 		       "too small to handle the telnet NAWS option",
 		       (u_long)sizeof(vty->sb_buf), TELNET_NAWS_SB_LEN);
 	    else
@@ -1264,7 +1397,7 @@ vty_telnet_option (struct vty *vty, unsigned char *buf, int nbytes)
 		vty->width = ((vty->sb_buf[1] << 8)|vty->sb_buf[2]);
 		vty->height = ((vty->sb_buf[3] << 8)|vty->sb_buf[4]);
 #ifdef TELNET_OPTION_DEBUG
-		vty_out(vty, "TELNET NAWS window size negotiation completed: "
+		uty_out(vty, "TELNET NAWS window size negotiation completed: "
 			      "width %d, height %d%s",
 			vty->width, vty->height, VTY_NEWLINE);
 #endif
@@ -1321,6 +1454,7 @@ vty_execute (struct vty *vty)
 static void
 vty_escape_map (unsigned char c, struct vty *vty)
 {
+  assert(vty_lock_count);
   switch (c)
     {
     case ('A'):
@@ -1347,12 +1481,13 @@ vty_escape_map (unsigned char c, struct vty *vty)
 static void
 vty_buffer_reset (struct vty *vty)
 {
+  assert(vty_lock_count);
   buffer_reset (vty->obuf);
   vty_prompt (vty);
   vty_redraw_line (vty);
 }
 
-/* Read data via vty socket. */
+/* Callback: Read data via vty socket. */
 static int
 vty_read (struct thread *thread)
 {
@@ -1362,6 +1497,9 @@ vty_read (struct thread *thread)
 
   int vty_sock = THREAD_FD (thread);
   struct vty *vty = THREAD_ARG (thread);
+
+  LOCK
+
   vty->t_read = NULL;
 
   /* Read raw data from socket */
@@ -1372,10 +1510,11 @@ vty_read (struct thread *thread)
 	  if (ERRNO_IO_RETRY(errno))
 	    {
 	      vty_event (VTY_READ, vty_sock, vty);
+	      UNLOCK
 	      return 0;
 	    }
 	  vty->monitor = 0; /* disable monitoring to avoid infinite recursion */
-	  zlog_warn("%s: read error on vty client fd %d, closing: %s",
+	  uzlog(NULL, LOG_WARNING, "%s: read error on vty client fd %d, closing: %s",
 		    __func__, vty->fd, safe_strerror(errno));
 	}
       buffer_reset(vty->obuf);
@@ -1523,7 +1662,7 @@ vty_read (struct thread *thread)
 	  break;
 	case '\n':
 	case '\r':
-	  vty_out (vty, "%s", VTY_NEWLINE);
+	  uty_out (vty, "%s", VTY_NEWLINE);
 	  vty_execute (vty);
 	  break;
 	case '\t':
@@ -1553,16 +1692,19 @@ vty_read (struct thread *thread)
 
   /* Check status. */
   if (vty->status == VTY_CLOSE)
-    vty_close (vty);
+    uty_close (vty);
   else
     {
       vty_event (VTY_WRITE, vty_sock, vty);
       vty_event (VTY_READ, vty_sock, vty);
     }
+
+  UNLOCK
+
   return 0;
 }
 
-/* Flush buffer to the vty. */
+/* Callback: Flush buffer to the vty. */
 static int
 vty_flush (struct thread *thread)
 {
@@ -1571,9 +1713,11 @@ vty_flush (struct thread *thread)
   int vty_sock = THREAD_FD (thread);
   struct vty *vty = THREAD_ARG (thread);
 
+  LOCK
+
   vty->t_write = NULL;
 
-  /* Tempolary disable read thread. */
+  /* Temporary disable read thread. */
   if ((vty->lines == 0) && vty->t_read)
     {
       thread_cancel (vty->t_read);
@@ -1598,14 +1742,14 @@ vty_flush (struct thread *thread)
     {
     case BUFFER_ERROR:
       vty->monitor = 0; /* disable monitoring to avoid infinite recursion */
-      zlog_warn("buffer_flush failed on vty client fd %d, closing",
+      uzlog(NULL, LOG_WARNING, "buffer_flush failed on vty client fd %d, closing",
 		vty->fd);
       buffer_reset(vty->obuf);
-      vty_close(vty);
-      return 0;
+      uty_close(vty);
+      break;
     case BUFFER_EMPTY:
       if (vty->status == VTY_CLOSE)
-	vty_close (vty);
+	uty_close (vty);
       else
 	{
 	  vty->status = VTY_NORMAL;
@@ -1621,6 +1765,8 @@ vty_flush (struct thread *thread)
       break;
     }
 
+  UNLOCK
+
   return 0;
 }
 
@@ -1630,6 +1776,8 @@ vty_create (int vty_sock, union sockunion *su)
 {
   struct vty *vty;
 
+  assert(vty_lock_count);
+
   /* Allocate new vty structure and set up default values. */
   vty = vty_new ();
   vty->fd = vty_sock;
@@ -1669,17 +1817,17 @@ vty_create (int vty_sock, union sockunion *su)
       /* Vty is not available if password isn't set. */
       if (host.password == NULL && host.password_encrypt == NULL)
 	{
-	  vty_out (vty, "Vty password is not set.%s", VTY_NEWLINE);
+	  uty_out (vty, "Vty password is not set.%s", VTY_NEWLINE);
 	  vty->status = VTY_CLOSE;
-	  vty_close (vty);
+	  uty_close (vty);
 	  return NULL;
 	}
     }
 
   /* Say hello to the world. */
-  vty_hello (vty);
+  uty_hello (vty);
   if (! no_password_check)
-    vty_out (vty, "%sUser Access Verification%s%s", VTY_NEWLINE, VTY_NEWLINE, VTY_NEWLINE);
+    uty_out (vty, "%sUser Access Verification%s%s", VTY_NEWLINE, VTY_NEWLINE, VTY_NEWLINE);
 
   /* Setting up terminal. */
   vty_will_echo (vty);
@@ -1698,7 +1846,7 @@ vty_create (int vty_sock, union sockunion *su)
   return vty;
 }
 
-/* Accept connection from the network. */
+/* Callback: Accept connection from the network. */
 static int
 vty_accept (struct thread *thread)
 {
@@ -1711,6 +1859,8 @@ vty_accept (struct thread *thread)
   struct prefix *p = NULL;
   struct access_list *acl = NULL;
 
+  LOCK
+
   accept_sock = THREAD_FD (thread);
 
   /* We continue hearing vty socket. */
@@ -1722,7 +1872,8 @@ vty_accept (struct thread *thread)
   vty_sock = sockunion_accept (accept_sock, &su);
   if (vty_sock < 0)
     {
-      zlog_warn ("can't accept vty socket : %s", safe_strerror (errno));
+      uzlog (NULL, LOG_WARNING, "can't accept vty socket : %s", safe_strerror (errno));
+      UNLOCK
       return -1;
     }
   set_nonblocking(vty_sock);
@@ -1736,7 +1887,7 @@ vty_accept (struct thread *thread)
 	  (access_list_apply (acl, p) == FILTER_DENY))
 	{
 	  char *buf;
-	  zlog (NULL, LOG_INFO, "Vty connection refused from %s",
+	  uzlog (NULL, LOG_INFO, "Vty connection refused from %s",
 		(buf = sockunion_su2str (&su)));
 	  free (buf);
 	  close (vty_sock);
@@ -1746,6 +1897,7 @@ vty_accept (struct thread *thread)
 
 	  prefix_free (p);
 
+	  UNLOCK
 	  return 0;
 	}
     }
@@ -1758,7 +1910,7 @@ vty_accept (struct thread *thread)
 	  (access_list_apply (acl, p) == FILTER_DENY))
 	{
 	  char *buf;
-	  zlog (NULL, LOG_INFO, "Vty connection refused from %s",
+	  uzlog (NULL, LOG_INFO, "Vty connection refused from %s",
 		(buf = sockunion_su2str (&su)));
 	  free (buf);
 	  close (vty_sock);
@@ -1768,6 +1920,7 @@ vty_accept (struct thread *thread)
 
 	  prefix_free (p);
 
+	  UNLOCK
 	  return 0;
 	}
     }
@@ -1779,11 +1932,12 @@ vty_accept (struct thread *thread)
   ret = setsockopt (vty_sock, IPPROTO_TCP, TCP_NODELAY,
 		    (char *) &on, sizeof (on));
   if (ret < 0)
-    zlog (NULL, LOG_INFO, "can't set sockopt to vty_sock : %s",
+    uzlog (NULL, LOG_INFO, "can't set sockopt to vty_sock : %s",
 	  safe_strerror (errno));
 
   vty = vty_create (vty_sock, &su);
 
+  UNLOCK
   return 0;
 }
 
@@ -1798,6 +1952,8 @@ vty_serv_sock_addrinfo (const char *hostname, unsigned short port)
   int sock;
   char port_str[BUFSIZ];
 
+  assert(vty_lock_count);
+
   memset (&req, 0, sizeof (struct addrinfo));
   req.ai_flags = AI_PASSIVE;
   req.ai_family = AF_UNSPEC;
@@ -1853,6 +2009,7 @@ vty_serv_sock_addrinfo (const char *hostname, unsigned short port)
 }
 #endif /* HAVE_IPV6 && ! NRL */
 
+#if defined(HAVE_IPV6) && defined(NRL) || !defined(HAVE_IPV6)
 /* Make vty server socket. */
 static void
 vty_serv_sock_family (const char* addr, unsigned short port, int family)
@@ -1862,6 +2019,8 @@ vty_serv_sock_family (const char* addr, unsigned short port, int family)
   int accept_sock;
   void* naddr=NULL;
 
+  assert(vty_lock_count);
+
   memset (&su, 0, sizeof (union sockunion));
   su.sa.sa_family = family;
   if(addr)
@@ -1879,11 +2038,11 @@ vty_serv_sock_family (const char* addr, unsigned short port, int family)
     switch(inet_pton(family,addr,naddr))
     {
       case -1:
-        zlog_err("bad address %s",addr);
+        uzlog(NULL, LOG_ERR, "bad address %s",addr);
 	naddr=NULL;
 	break;
       case 0:
-        zlog_err("error translating address %s: %s",addr,safe_strerror(errno));
+        uzlog(NULL, LOG_ERR, "error translating address %s: %s",addr,safe_strerror(errno));
 	naddr=NULL;
     }
 
@@ -1900,7 +2059,7 @@ vty_serv_sock_family (const char* addr, unsigned short port, int family)
   ret = sockunion_bind (accept_sock, &su, port, naddr);
   if (ret < 0)
     {
-      zlog_warn("can't bind socket");
+      uzlog(NULL, LOG_WARNING, "can't bind socket");
       close (accept_sock);	/* Avoid sd leak. */
       return;
     }
@@ -1917,6 +2076,7 @@ vty_serv_sock_family (const char* addr, unsigned short port, int family)
   /* Add vty server event. */
   vty_event (VTY_SERV, accept_sock, NULL);
 }
+#endif /* defined(HAVE_IPV6) && defined(NRL) || !defined(HAVE_IPV6) */
 
 #ifdef VTYSH
 /* For sockaddr_un. */
@@ -1932,6 +2092,8 @@ vty_serv_un (const char *path)
   mode_t old_mask;
   struct zprivs_ids_t ids;
 
+  assert(vty_lock_count);
+
   /* First of all, unlink existing socket */
   unlink (path);
 
@@ -1942,7 +2104,7 @@ vty_serv_un (const char *path)
   sock = socket (AF_UNIX, SOCK_STREAM, 0);
   if (sock < 0)
     {
-      zlog_err("Cannot create unix stream socket: %s", safe_strerror(errno));
+      uzlog(NULL, LOG_ERR, "Cannot create unix stream socket: %s", safe_strerror(errno));
       return;
     }
 
@@ -1959,7 +2121,7 @@ vty_serv_un (const char *path)
   ret = bind (sock, (struct sockaddr *) &serv, len);
   if (ret < 0)
     {
-      zlog_err("Cannot bind path %s: %s", path, safe_strerror(errno));
+      ulog(NULL, LOG_ERR, "Cannot bind path %s: %s", path, safe_strerror(errno));
       close (sock);	/* Avoid sd leak. */
       return;
     }
@@ -1967,7 +2129,7 @@ vty_serv_un (const char *path)
   ret = listen (sock, 5);
   if (ret < 0)
     {
-      zlog_err("listen(fd %d) failed: %s", sock, safe_strerror(errno));
+      uzlog(NULL, LOG_ERR, "listen(fd %d) failed: %s", sock, safe_strerror(errno));
       close (sock);	/* Avoid sd leak. */
       return;
     }
@@ -1981,7 +2143,7 @@ vty_serv_un (const char *path)
       /* set group of socket */
       if ( chown (path, -1, ids.gid_vty) )
         {
-          zlog_err ("vty_serv_un: could chown socket, %s",
+          uzlog (NULL, LOG_ERR, "vty_serv_un: could chown socket, %s",
                      safe_strerror (errno) );
         }
     }
@@ -2000,6 +2162,8 @@ vtysh_accept (struct thread *thread)
   struct sockaddr_un client;
   struct vty *vty;
 
+  LOCK
+
   accept_sock = THREAD_FD (thread);
 
   vty_event (VTYSH_SERV, accept_sock, NULL);
@@ -2012,15 +2176,17 @@ vtysh_accept (struct thread *thread)
 
   if (sock < 0)
     {
-      zlog_warn ("can't accept vty socket : %s", safe_strerror (errno));
+      uzlog (NULL, LOG_WARNING, "can't accept vty socket : %s", safe_strerror (errno));
+      UNLOCK
       return -1;
     }
 
   if (set_nonblocking(sock) < 0)
     {
-      zlog_warn ("vtysh_accept: could not set vty socket %d to non-blocking,"
+      uzlog (NULL, LOG_WARNING, "vtysh_accept: could not set vty socket %d to non-blocking,"
                  " %s, closing", sock, safe_strerror (errno));
       close (sock);
+      UNLOCK
       return -1;
     }
 
@@ -2035,12 +2201,15 @@ vtysh_accept (struct thread *thread)
 
   vty_event (VTYSH_READ, sock, vty);
 
+  UNLOCK
   return 0;
 }
 
 static int
 vtysh_flush(struct vty *vty)
 {
+  assert(vty_lock_count);
+
   switch (buffer_flush_available(vty->obuf, vty->fd))
     {
     case BUFFER_PENDING:
@@ -2048,9 +2217,9 @@ vtysh_flush(struct vty *vty)
       break;
     case BUFFER_ERROR:
       vty->monitor = 0; /* disable monitoring to avoid infinite recursion */
-      zlog_warn("%s: write error to fd %d, closing", __func__, vty->fd);
+      uzlog(NULL, LOG_WARNING, "%s: write error to fd %d, closing", __func__, vty->fd);
       buffer_reset(vty->obuf);
-      vty_close(vty);
+      uty_close(vty);
       return -1;
       break;
     case BUFFER_EMPTY:
@@ -2070,6 +2239,8 @@ vtysh_read (struct thread *thread)
   unsigned char *p;
   u_char header[4] = {0, 0, 0, 0};
 
+  LOCK
+
   sock = THREAD_FD (thread);
   vty = THREAD_ARG (thread);
   vty->t_read = NULL;
@@ -2081,17 +2252,19 @@ vtysh_read (struct thread *thread)
 	  if (ERRNO_IO_RETRY(errno))
 	    {
 	      vty_event (VTYSH_READ, sock, vty);
+	      UNLOCK
 	      return 0;
 	    }
 	  vty->monitor = 0; /* disable monitoring to avoid infinite recursion */
-	  zlog_warn("%s: read failed on vtysh client fd %d, closing: %s",
+	  uzlog(NULL, LOG_WARNING, "%s: read failed on vtysh client fd %d, closing: %s",
 		    __func__, sock, safe_strerror(errno));
 	}
       buffer_reset(vty->obuf);
-      vty_close (vty);
+      uty_close (vty);
 #ifdef VTYSH_DEBUG
       printf ("close vtysh\n");
 #endif /* VTYSH_DEBUG */
+      UNLOCK
       return 0;
     }
 
@@ -2121,22 +2294,29 @@ vtysh_read (struct thread *thread)
 
 	  if (!vty->t_write && (vtysh_flush(vty) < 0))
 	    /* Try to flush results; exit if a write error occurs. */
+	    UNLOCK
 	    return 0;
 	}
     }
 
   vty_event (VTYSH_READ, sock, vty);
 
+  UNLOCK
   return 0;
 }
 
+/* Callback */
 static int
 vtysh_write (struct thread *thread)
 {
   struct vty *vty = THREAD_ARG (thread);
 
+  LOCK
+
   vty->t_write = NULL;
   vtysh_flush(vty);
+
+  UNLOCK
   return 0;
 }
 
@@ -2146,6 +2326,8 @@ vtysh_write (struct thread *thread)
 void
 vty_serv_sock (const char *addr, unsigned short port, const char *path)
 {
+  LOCK
+
   /* If port is set to 0, do not listen on TCP/IP at all! */
   if (port)
     {
@@ -2165,6 +2347,8 @@ vty_serv_sock (const char *addr, unsigned short port, const char *path)
 #ifdef VTYSH
   vty_serv_un (path);
 #endif /* VTYSH */
+
+  UNLOCK
 }
 
 /* Close vty interface.  Warning: call this only from functions that
@@ -2174,8 +2358,18 @@ vty_serv_sock (const char *addr, unsigned short port, const char *path)
 void
 vty_close (struct vty *vty)
 {
+  LOCK
+  uty_close(vty);
+  UNLOCK
+}
+
+static void
+uty_close (struct vty *vty)
+{
   int i;
 
+  assert(vty_lock_count);
+
   /* Cancel threads.*/
   if (vty->t_read)
     thread_cancel (vty->t_read);
@@ -2208,30 +2402,33 @@ vty_close (struct vty *vty)
     XFREE (MTYPE_VTY, vty->buf);
 
   /* Check configure. */
-  vty_config_unlock (vty);
+  uty_config_unlock (vty);
 
   /* OK free vty. */
   XFREE (MTYPE_VTY, vty);
 }
 
-/* When time out occur output message then close connection. */
+/* Callback: When time out occur output message then close connection. */
 static int
 vty_timeout (struct thread *thread)
 {
   struct vty *vty;
 
+  LOCK;
+
   vty = THREAD_ARG (thread);
   vty->t_timeout = NULL;
   vty->v_timeout = 0;
 
   /* Clear buffer*/
   buffer_reset (vty->obuf);
-  vty_out (vty, "%sVty connection is timed out.%s", VTY_NEWLINE, VTY_NEWLINE);
+  uty_out (vty, "%sVty connection is timed out.%s", VTY_NEWLINE, VTY_NEWLINE);
 
   /* Close connection. */
   vty->status = VTY_CLOSE;
-  vty_close (vty);
+  uty_close (vty);
 
+  UNLOCK
   return 0;
 }
 
@@ -2250,6 +2447,8 @@ vty_read_file (FILE *confp)
   /* Execute configuration file */
   ret = config_from_file (vty, confp);
 
+  LOCK
+
   if ( !((ret == CMD_SUCCESS) || (ret == CMD_ERR_NOTHING_TODO)) )
     {
       switch (ret)
@@ -2263,11 +2462,12 @@ vty_read_file (FILE *confp)
        }
       fprintf (stderr, "Error occured during reading below line.\n%s\n",
 	       vty->buf);
-      vty_close (vty);
+      uty_close (vty);
       exit (1);
     }
 
-  vty_close (vty);
+  uty_close (vty);
+  UNLOCK
 }
 
 static FILE *
@@ -2400,7 +2600,7 @@ vty_read_config (char *config_file,
         {
           ret = stat (integrate_default, &conf_stat);
           if (ret >= 0)
-            return;
+              return;
         }
 #endif /* VTYSH */
 
@@ -2445,18 +2645,19 @@ vty_log (const char *level, const char *proto_str,
   unsigned int i;
   struct vty *vty;
 
+  assert(vty_lock_count);
+
   if (!vtyvec)
     return;
 
-  for (i = 0; i < vector_active (vtyvec); i++)
-    if ((vty = vector_slot (vtyvec, i)) != NULL)
-      if (vty->monitor)
-	{
-	  va_list ac;
-	  va_copy(ac, va);
-	  vty_log_out (vty, level, proto_str, format, ctl, ac);
-	  va_end(ac);
-	}
+    for (i = 0; i < vector_active (vtyvec); i++)
+      if (((vty = vector_slot (vtyvec, i)) != NULL) && vty->monitor)
+        {
+          va_list ac;
+          va_copy(ac, va);
+          vty_log_out (vty, level, proto_str, format, ctl, ac);
+          va_end(ac);
+        }
 }
 
 /* Async-signal-safe version of vty_log for fixed strings. */
@@ -2488,17 +2689,32 @@ vty_log_fixed (const char *buf, size_t len)
 int
 vty_config_lock (struct vty *vty)
 {
+  int result;
+  LOCK
   if (vty_config == 0)
     {
       vty->config = 1;
       vty_config = 1;
     }
-  return vty->config;
+  result = vty->config;
+  UNLOCK
+  return result;
 }
 
 int
 vty_config_unlock (struct vty *vty)
 {
+  int result;
+  LOCK
+  result = uty_config_unlock(vty);
+  UNLOCK
+  return result;
+}
+
+static int
+uty_config_unlock (struct vty *vty)
+{
+  assert(vty_lock_count);
   if (vty_config == 1 && vty->config == 1)
     {
       vty->config = 0;
@@ -2515,6 +2731,8 @@ vty_event (enum event event, int sock, struct vty *vty)
 {
   struct thread *vty_serv_thread;
 
+  assert(vty_lock_count);
+
   switch (event)
     {
     case VTY_SERV:
@@ -2596,6 +2814,8 @@ exec_timeout (struct vty *vty, const char *min_str, const char *sec_str)
 {
   unsigned long timeout = 0;
 
+  LOCK
+
   /* min_str and sec_str are already checked by parser.  So it must be
      all digit string. */
   if (min_str)
@@ -2610,7 +2830,7 @@ exec_timeout (struct vty *vty, const char *min_str, const char *sec_str)
   vty->v_timeout = timeout;
   vty_event (VTY_TIMEOUT_RESET, 0, vty);
 
-
+  UNLOCK
   return CMD_SUCCESS;
 }
 
@@ -2887,12 +3107,14 @@ vty_reset ()
   struct vty *vty;
   struct thread *vty_serv_thread;
 
+  LOCK
+
   for (i = 0; i < vector_active (vtyvec); i++)
     if ((vty = vector_slot (vtyvec, i)) != NULL)
       {
 	buffer_reset (vty->obuf);
 	vty->status = VTY_CLOSE;
-	vty_close (vty);
+	uty_close (vty);
       }
 
   for (i = 0; i < vector_active (Vvty_serv_thread); i++)
@@ -2916,6 +3138,7 @@ vty_reset ()
       XFREE(MTYPE_VTY, vty_ipv6_accesslist_name);
       vty_ipv6_accesslist_name = NULL;
     }
+  UNLOCK
 }
 
 static void
@@ -2945,25 +3168,51 @@ vty_get_cwd ()
 int
 vty_shell (struct vty *vty)
 {
+  LOCK
+  int result;
+  result = uty_shell (vty);
+  UNLOCK
+  return result;
+}
+
+static int
+uty_shell (struct vty *vty)
+{
   return ((vty == NULL) || (vty->type == VTY_SHELL)) ? 1 : 0;
 }
 
 int
 vty_shell_serv (struct vty *vty)
 {
-  return vty->type == VTY_SHELL_SERV ? 1 : 0;
+  LOCK
+  int result;
+  result = ((vty->type == VTY_SHELL_SERV) ? 1 : 0);
+  UNLOCK
+  return result;
 }
 
 void
 vty_init_vtysh ()
 {
+  LOCK
   vtyvec = vector_init (0);
+  UNLOCK
+}
+
+/* Install vty's own commands like `who' command. */
+void
+vty_init_r (struct thread_master *master_thread)
+{
+  vty_mutex = qpt_mutex_init(vty_mutex, qpt_mutex_quagga);
+  vty_init(master_thread);
 }
 
 /* Install vty's own commands like `who' command. */
 void
 vty_init (struct thread_master *master_thread)
 {
+  LOCK
+
   /* For further configuration read, preserve current directory. */
   vty_save_cwd ();
 
@@ -3005,11 +3254,21 @@ vty_init (struct thread_master *master_thread)
   install_element (VTY_NODE, &vty_ipv6_access_class_cmd);
   install_element (VTY_NODE, &no_vty_ipv6_access_class_cmd);
 #endif /* HAVE_IPV6 */
+
+  UNLOCK
+}
+
+void
+vty_terminate_r (void)
+{
+  vty_terminate();
+  vty_mutex = qpt_mutex_destroy(vty_mutex, 1);
 }
 
 void
 vty_terminate (void)
 {
+  LOCK
   if (vty_cwd)
     XFREE (MTYPE_TMP, vty_cwd);
 
@@ -3019,4 +3278,8 @@ vty_terminate (void)
       vector_free (vtyvec);
       vector_free (Vvty_serv_thread);
     }
+  UNLOCK
 }
+
+#undef LOCK
+#undef UNLOCK
diff --git a/lib/vty.h b/lib/vty.h
index 1e7f1261..4568f775 100644
--- a/lib/vty.h
+++ b/lib/vty.h
@@ -23,6 +23,7 @@ Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 
 #include "thread.h"
 #include "log.h"
+#include "qpthreads.h"
 
 #define VTY_BUFSIZ 512
 #define VTY_MAXHIST 20
@@ -205,10 +206,18 @@ do {
 
 /* Exported variables */
 extern char integrate_default[];
+extern qpt_mutex_t* vty_mutex;
+#ifndef NDEBUG
+extern int vty_lock_count;
+#endif
 
 /* Prototypes. */
+extern void vty_init_r (struct thread_master *);
+extern void vty_terminate_r (void);
+
 extern void vty_init (struct thread_master *);
 extern void vty_init_vtysh (void);
+extern void vty_terminate_r (void);
 extern void vty_terminate (void);
 extern void vty_reset (void);
 extern struct vty *vty_new (void);