lib: get rid of extraneous output with vty_prepend

the vty_*prepend* family can be used to reduce the amount of output
produced by "show running-config" and "write ...". it buffers output in
struct vty->prepend (1024 bytes) and outputs it when vty_out is called.
if vty_out isn't called, it can be removed with vty_unprepend later.

applied on zebra and ospfd to get rid of empty interface blocks.

1 files changed, 25 insertions, 0 deletions

diff --git a/lib/vty.c b/lib/vty.c
index 9c58b50d..fa3f7718 100644
--- a/lib/vty.c
+++ b/lib/vty.c
@@ -90,6 +90,25 @@ static u_char restricted_mode = 0;
 char integrate_default[] = SYSCONFDIR INTEGRATE_DEFAULT_CONFIG;
 
 
+void
+vty_prepend (struct vty *vty, const char *format, ...)
+{
+  va_list args;
+
+  va_start (args, format);
+  vsnprintf (vty->prepend + vty->prepend_pos,
+	     sizeof(vty->prepend) - vty->prepend_pos,
+	     format, args);
+  vty->prepend_pos = strlen (vty->prepend);
+  va_end (args);
+}
+
+void
+vty_unprepend (struct vty *vty)
+{
+  vty->prepend_pos = 0;
+}
+
 /* VTY standard output function. */
 int
 vty_out (struct vty *vty, const char *format, ...)
@@ -100,6 +119,12 @@ vty_out (struct vty *vty, const char *format, ...)
   char buf[1024];
   char *p = NULL;
 
+  if (vty->prepend_pos)
+    {
+      vty->prepend_pos = 0;
+      vty_out (vty, "%s", vty->prepend);
+    }
+
   if (vty_shell (vty))
     {
       va_start (args, format);