plugin.c: prevent re-adding read functions

When multiple LoadPlugin options are used with a plugin, the plugin is
only loaded once, however the plugin's read function is invoked
multiple times at every interval. This in turn causes undesired
redundant data to be sent to the write plugins.

This patch prevents a plugin's read function from being re-added to
the read_heap and read_list during plugin registration.

Signed-off-by: Blaise Tarr <blaise.tarr@gmail.com>
Signed-off-by: Florian Forster <octo@huhu.verplant.org>

diff --git a/src/plugin.c b/src/plugin.c
index 0f360c0f3eb5a0f952440483da19ec9ead4fd3fd..52a5ea088cfb9537e5d5c8f2f0b7e905413cf6b4 100644 (file)
--- a/src/plugin.c
+++ b/src/plugin.c
@@ -728,26 +728,36 @@ static int plugin_insert_read (read_func_t *rf)
                }
        }
 
-       le = llentry_create (rf->rf_name, rf);
+       le = llist_search (read_list, rf->rf_name);
        if (le == NULL)
        {
-               pthread_mutex_unlock (&read_lock);
-               ERROR ("plugin_insert_read: llentry_create failed.");
-               return (-1);
-       }
+               le = llentry_create (rf->rf_name, rf);
+               if (le == NULL)
+               {
+                       pthread_mutex_unlock (&read_lock);
+                       ERROR ("plugin_insert_read: llentry_create failed.");
+                       return (-1);
+               }
+
+               status = c_heap_insert (read_heap, rf);
+               if (status != 0)
+               {
+                       pthread_mutex_unlock (&read_lock);
+                       ERROR ("plugin_insert_read: c_heap_insert failed.");
+                       llentry_destroy (le);
+                       return (-1);
+               }
 
-       status = c_heap_insert (read_heap, rf);
-       if (status != 0)
+               /* This does not fail. */
+               llist_append (read_list, le);
+       }
+       else
        {
-               pthread_mutex_unlock (&read_lock);
-               ERROR ("plugin_insert_read: c_heap_insert failed.");
-               llentry_destroy (le);
-               return (-1);
+               INFO ("plugin: plugin_insert_read: "
+                               "read function for plugin `%s' already added.",
+                               rf->rf_name);
        }
 
-       /* This does not fail. */
-       llist_append (read_list, le);
-
        pthread_mutex_unlock (&read_lock);
        return (0);
 } /* int plugin_insert_read */