src/filter_chain.[ch]: Implement the built-in `return' target.

The `stop' target now aborts all processing of the value completely, `return'
only stops the current chain and continues processing the parent chain.

The collectd.conf(5) manual page has been updated and the `FC_ACTION_*' defines
have been renamed to `FC_TARGET_*'.

diff --git a/src/collectd.conf.pod b/src/collectd.conf.pod
index a1846003ae8a91e8bd741b6ed6edbef6bfd33e9c..87e86d46a928afd02e1ccd89c709d0d1315b4458 100644 (file)
--- a/src/collectd.conf.pod
+++ b/src/collectd.conf.pod
@@ -2623,10 +2623,31 @@ plugins to be loaded:
 
 =over 4
 
+=item B<return>
+
+Signals the "return" condition. This causes the current chain to stop
+processing the value and returns control to the calling chain. The calling
+chain will continue processing targets and rules just after the B<jump> target
+(see below). This is very similar to the B<RETURN> target of iptables, see
+L<iptables(8)>.
+
+This target does not have any options.
+
+Example:
+
+ Target "return"
+
 =item B<stop>
 
-Does nothing except returning with the stop condition, causing processing of
-the current chain to be aborted.
+Signals the "stop" condition, causing processing of the value to be aborted
+immediately. This is similar to the B<DROP> target of iptables, see
+L<iptables(8)>.
+
+This target does not have any options.
+
+Example:
+
+ Target "stop"
 
 =item B<write>
 
@@ -2641,10 +2662,6 @@ Available options:
 Name of the write plugin to which the data should be sent. This option may be
 given multiple times to send the data to more than one write plugin.
 
-Example:
-
- Target "stop"
-
 =back
 
 If no plugin is explicitly specified, the values will be sent to all available
@@ -2661,6 +2678,8 @@ Example:
 Starts processing the rules of another chain. If the end of that chain is
 reached, or a stop condition is encountered, processing will continue right
 after the B<jump> target, i.E<nbsp>e. with the next target or the next rule.
+This is similar to the B<-j> command line option of iptables, see
+L<iptables(8)>.
 
 Available options:
 
@@ -2680,22 +2699,6 @@ Example:
 
 =back
 
-=head2 Backwards compatibility
-
-If you use collectd with an old configuration, i.E<nbsp>e. one without a
-B<Chain> block, it will behave as it used to. This is equivalent to the
-following configuration:
-
- <Chain "main">
-   Target "write"
- </Chain>
-
-If you specify a B<Chain> block anywhere, the B<write> target will not be added
-anywhere and you will have to make sure that it is called where appropriate. We
-suggest to add the above snippet as default target to your main chain.
-
-TODO: Notifications will be implemented using chains, too. Describe that here!
-
 =head2 Available matches
 
 =over 4
@@ -2768,6 +2771,22 @@ Example:
 
 =back
 
+=head2 Backwards compatibility
+
+If you use collectd with an old configuration, i.E<nbsp>e. one without a
+B<Chain> block, it will behave as it used to. This is equivalent to the
+following configuration:
+
+ <Chain "main">
+   Target "write"
+ </Chain>
+
+If you specify a B<Chain> block anywhere, the B<write> target will not be added
+anywhere and you will have to make sure that it is called where appropriate. We
+suggest to add the above snippet as default target to your main chain.
+
+TODO: Notifications will be implemented using chains, too. Describe that here!
+
 =head2 Examples
 
 Ignore all values, where the hostname does not contain a dot, i.E<nbsp>e. can't
@@ -2791,6 +2810,7 @@ L<collectd-perl(5)>,
 L<collectd-unixsock(5)>,
 L<types.db(5)>,
 L<hddtemp(8)>,
+L<iptables(8)>,
 L<kstat(3KSTAT)>,
 L<mbmon(1)>,
 L<pcre(3)>,

diff --git a/src/filter_chain.c b/src/filter_chain.c
index 109a32a03c55e13b9f903abdd0abb97cb5113b25..01cd224cde5d430bb4fcf9fe7b949d32ed1cdbea 100644 (file)
--- a/src/filter_chain.c
+++ b/src/filter_chain.c
@@ -567,8 +567,7 @@ int fc_process_chain (const data_set_t *ds, value_list_t *vl, /* {{{ */
 
   DEBUG ("fc_process_chain (chain = %s);", chain->name);
 
-  status = FC_ACTION_CONTINUE;
-
+  status = FC_TARGET_CONTINUE;
   for (rule = chain->rules; rule != NULL; rule = rule->next)
   {
     fc_match_t *match;
@@ -595,7 +594,10 @@ int fc_process_chain (const data_set_t *ds, value_list_t *vl, /* {{{ */
 
     /* for-loop has been aborted: Either error or no match. */
     if (match != NULL)
+    {
+      status = FC_TARGET_CONTINUE;
       continue;
+    }
 
     if (rule->name[0] != 0)
     {
@@ -614,9 +616,11 @@ int fc_process_chain (const data_set_t *ds, value_list_t *vl, /* {{{ */
         WARNING ("fc_process_chain (%s): A target failed.", chain->name);
         continue;
       }
-      else if (status == FC_ACTION_CONTINUE)
+      else if (status == FC_TARGET_CONTINUE)
         continue;
-      else if (status == FC_ACTION_STOP)
+      else if (status == FC_TARGET_STOP)
+        break;
+      else if (status == FC_TARGET_RETURN)
         break;
       else
       {
@@ -626,25 +630,37 @@ int fc_process_chain (const data_set_t *ds, value_list_t *vl, /* {{{ */
       }
     }
 
-    if (status == FC_ACTION_STOP)
+    if ((status == FC_TARGET_STOP)
+        || (status == FC_TARGET_RETURN))
     {
       if (rule->name[0] != 0)
       {
         DEBUG ("fc_process_chain (%s): Rule `%s' signaled "
-            "the stop condition.",
-            chain->name, rule->name);
+            "the %s condition.",
+            chain->name, rule->name,
+            (status == FC_TARGET_STOP) ? "stop" : "return");
       }
       break;
     }
+    else
+    {
+      status = FC_TARGET_CONTINUE;
+    }
   } /* for (rule) */
 
-  /* for-loop has been aborted: A target returned `FC_ACTION_STOP' */
+  if (status == FC_TARGET_STOP)
+    return (FC_TARGET_STOP);
+  else if (status == FC_TARGET_RETURN)
+    return (FC_TARGET_CONTINUE);
+
+  /* for-loop has been aborted: A target returned `FC_TARGET_STOP' */
   if (rule != NULL)
-    return (0);
+    return (FC_TARGET_CONTINUE);
 
   DEBUG ("fc_process_chain (%s): Executing the default targets.",
       chain->name);
 
+  status = FC_TARGET_CONTINUE;
   for (target = chain->targets; target != NULL; target = target->next)
   {
     /* If we get here, all matches have matched the value. Execute the
@@ -656,9 +672,11 @@ int fc_process_chain (const data_set_t *ds, value_list_t *vl, /* {{{ */
       WARNING ("fc_process_chain (%s): The default target failed.",
           chain->name);
     }
-    else if (status == FC_ACTION_CONTINUE)
+    else if (status == FC_TARGET_CONTINUE)
       continue;
-    else if (status == FC_ACTION_STOP)
+    else if (status == FC_TARGET_STOP)
+      break;
+    else if (status == FC_TARGET_RETURN)
       break;
     else
     {
@@ -668,14 +686,24 @@ int fc_process_chain (const data_set_t *ds, value_list_t *vl, /* {{{ */
     }
   }
 
-  if (target != NULL)
+  if ((status == FC_TARGET_STOP)
+      || (status == FC_TARGET_RETURN))
   {
+    assert (target != NULL);
     DEBUG ("fc_process_chain (%s): Default target `%s' signaled "
-        "the stop condition.",
-        chain->name, target->name);
+        "the %s condition.",
+        chain->name, target->name,
+        (status == FC_TARGET_STOP) ? "stop" : "return");
+    if (status == FC_TARGET_STOP)
+      return (FC_TARGET_STOP);
+    else
+      return (FC_TARGET_CONTINUE);
   }
 
-  return (0);
+  DEBUG ("fc_process_chain (%s): Signaling `continue' at end of chain.",
+      chain->name);
+
+  return (FC_TARGET_CONTINUE);
 } /* }}} int fc_process_chain */
 
 /*
@@ -756,16 +784,24 @@ static int fc_bit_jump_invoke (const data_set_t *ds, /* {{{ */
   status = fc_process_chain (ds, vl, chain);
   if (status < 0)
     return (status);
-
-  return (FC_ACTION_CONTINUE);
+  else if (status == FC_TARGET_STOP)
+    return (FC_TARGET_STOP);
+  else
+    return (FC_TARGET_CONTINUE);
 } /* }}} int fc_bit_jump_invoke */
 
 static int fc_bit_stop_invoke (const data_set_t *ds, /* {{{ */
     value_list_t *vl, notification_meta_t **meta, void **user_data)
 {
-  return (FC_ACTION_STOP);
+  return (FC_TARGET_STOP);
 } /* }}} int fc_bit_stop_invoke */
 
+static int fc_bit_return_invoke (const data_set_t *ds, /* {{{ */
+    value_list_t *vl, notification_meta_t **meta, void **user_data)
+{
+  return (FC_TARGET_RETURN);
+} /* }}} int fc_bit_return_invoke */
+
 static int fc_bit_write_create (const oconfig_item_t *ci, /* {{{ */
     void **user_data)
 {
@@ -876,7 +912,7 @@ static int fc_bit_write_invoke (const data_set_t *ds, /* {{{ */
     } /* for (i = 0; plugin_list[i] != NULL; i++) */
   }
 
-  return (FC_ACTION_CONTINUE);
+  return (FC_TARGET_CONTINUE);
 } /* }}} int fc_bit_write_invoke */
 
 static int fc_init_once (void) /* {{{ */
@@ -899,6 +935,12 @@ static int fc_init_once (void) /* {{{ */
   tproc.invoke  = fc_bit_stop_invoke;
   fc_register_target ("stop", tproc);
 
+  memset (&tproc, 0, sizeof (tproc));
+  tproc.create  = NULL;
+  tproc.destroy = NULL;
+  tproc.invoke  = fc_bit_return_invoke;
+  fc_register_target ("return", tproc);
+
   memset (&tproc, 0, sizeof (tproc));
   tproc.create  = fc_bit_write_create;
   tproc.destroy = fc_bit_write_destroy;

diff --git a/src/filter_chain.h b/src/filter_chain.h
index f2e22af2b36e8e0953734ccb17075191302c3782..2fd78d97038c54d79b5ae77b23a0f166ba4c2dbe 100644 (file)
--- a/src/filter_chain.h
+++ b/src/filter_chain.h
@@ -28,8 +28,9 @@
 #define FC_MATCH_NO_MATCH  0
 #define FC_MATCH_MATCHES   1
 
-#define FC_ACTION_CONTINUE 0
-#define FC_ACTION_STOP     1
+#define FC_TARGET_CONTINUE 0
+#define FC_TARGET_STOP     1
+#define FC_TARGET_RETURN   2
 
 /*
  * Match functions

diff --git a/src/target_set.c b/src/target_set.c
index e328da31a5327bd5541b2abcca1954744d38ca1f..70b0fdfc8c50164f294223336f06e40fa4c6e51f 100644 (file)
--- a/src/target_set.c
+++ b/src/target_set.c
@@ -249,7 +249,7 @@ static int ts_invoke (const data_set_t *ds, value_list_t *vl, /* {{{ */
   /* SET_FIELD (type); */
   SET_FIELD (type_instance);
 
-  return (0);
+  return (FC_TARGET_CONTINUE);
 } /* }}} int ts_invoke */
 
 void module_register (void)