X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=src%2Futils_threshold.c;h=b4fb8554d29df5f9e42c0ac937333878d05193ae;hb=772e60230767260801902eddd571bf6ff88c6423;hp=91407e0cbffa531468b86e1e81fc8aa9fb3b987d;hpb=365be1085ceadf47ee0af3bc850e1141542f7305;p=collectd.git

diff --git a/src/utils_threshold.c b/src/utils_threshold.c
index 91407e0c..b14c79b5 100644
--- a/src/utils_threshold.c
+++ b/src/utils_threshold.c
@@ -1,6 +1,9 @@
 /**
  * collectd - src/utils_threshold.c
- * Copyright (C) 2007  Florian octo Forster
+ * Copyright (C) 2007-2009  Florian octo Forster
+ * Copyright (C) 2008-2009  Sebastian Harl
+ * Copyright (C) 2009       Andrés J. Díaz
+ *
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
@@ -17,6 +20,8 @@
  *
  * Author:
  *   Florian octo Forster <octo at verplant.org>
+ *   Sebastian Harl <sh at tokkee.org>
+ *   Andrés J. Díaz <ajdiaz at connectical.com>
  **/
 
 #include "collectd.h"
@@ -24,6 +29,7 @@
 #include "plugin.h"
 #include "utils_avltree.h"
 #include "utils_cache.h"
+#include "utils_threshold.h"
 
 #include <assert.h>
 #include <pthread.h>
@@ -31,23 +37,15 @@
 /*
  * Private data structures
  * {{{ */
-typedef struct threshold_s
-{
-  char host[DATA_MAX_NAME_LEN];
-  char plugin[DATA_MAX_NAME_LEN];
-  char plugin_instance[DATA_MAX_NAME_LEN];
-  char type[DATA_MAX_NAME_LEN];
-  char type_instance[DATA_MAX_NAME_LEN];
-  gauge_t min;
-  gauge_t max;
-  int invert;
-} threshold_t;
+#define UT_FLAG_INVERT  0x01
+#define UT_FLAG_PERSIST 0x02
+#define UT_FLAG_PERCENTAGE 0x04
 /* }}} */
 
 /*
  * Private (static) variables
  * {{{ */
-static avl_tree_t     *threshold_tree = NULL;
+static c_avl_tree_t   *threshold_tree = NULL;
 static pthread_mutex_t threshold_lock = PTHREAD_MUTEX_INITIALIZER;
 /* }}} */
 
@@ -57,11 +55,31 @@ static pthread_mutex_t threshold_lock = PTHREAD_MUTEX_INITIALIZER;
  * The following functions add, delete, search, etc. configured thresholds to
  * the underlying AVL trees.
  * {{{ */
+static threshold_t *threshold_get (const char *hostname,
+    const char *plugin, const char *plugin_instance,
+    const char *type, const char *type_instance)
+{
+  char name[6 * DATA_MAX_NAME_LEN];
+  threshold_t *th = NULL;
+
+  format_name (name, sizeof (name),
+      (hostname == NULL) ? "" : hostname,
+      (plugin == NULL) ? "" : plugin, plugin_instance,
+      (type == NULL) ? "" : type, type_instance);
+  name[sizeof (name) - 1] = '\0';
+
+  if (c_avl_get (threshold_tree, name, (void *) &th) == 0)
+    return (th);
+  else
+    return (NULL);
+} /* threshold_t *threshold_get */
+
 static int ut_threshold_add (const threshold_t *th)
 {
   char name[6 * DATA_MAX_NAME_LEN];
   char *name_copy;
   threshold_t *th_copy;
+  threshold_t *th_ptr;
   int status = 0;
 
   if (format_name (name, sizeof (name), th->host,
@@ -87,16 +105,34 @@ static int ut_threshold_add (const threshold_t *th)
     return (-1);
   }
   memcpy (th_copy, th, sizeof (threshold_t));
+  th_ptr = NULL;
 
   DEBUG ("ut_threshold_add: Adding entry `%s'", name);
 
   pthread_mutex_lock (&threshold_lock);
-  status = avl_insert (threshold_tree, name_copy, th_copy);
+
+  th_ptr = threshold_get (th->host, th->plugin, th->plugin_instance,
+      th->type, th->type_instance);
+
+  while ((th_ptr != NULL) && (th_ptr->next != NULL))
+    th_ptr = th_ptr->next;
+
+  if (th_ptr == NULL) /* no such threshold yet */
+  {
+    status = c_avl_insert (threshold_tree, name_copy, th_copy);
+  }
+  else /* th_ptr points to the last threshold in the list */
+  {
+    th_ptr->next = th_copy;
+    /* name_copy isn't needed */
+    sfree (name_copy);
+  }
+
   pthread_mutex_unlock (&threshold_lock);
 
   if (status != 0)
   {
-    ERROR ("ut_threshold_add: avl_insert (%s) failed.", name);
+    ERROR ("ut_threshold_add: c_avl_insert (%s) failed.", name);
     sfree (name_copy);
     sfree (th_copy);
   }
@@ -113,6 +149,22 @@ static int ut_threshold_add (const threshold_t *th)
  * The following approximately two hundred functions are used to handle the
  * configuration and fill the threshold list.
  * {{{ */
+static int ut_config_type_datasource (threshold_t *th, oconfig_item_t *ci)
+{
+  if ((ci->values_num != 1)
+      || (ci->values[0].type != OCONFIG_TYPE_STRING))
+  {
+    WARNING ("threshold values: The `DataSource' option needs exactly one "
+	"string argument.");
+    return (-1);
+  }
+
+  sstrncpy (th->data_source, ci->values[0].value.string,
+      sizeof (th->data_source));
+
+  return (0);
+} /* int ut_config_type_datasource */
+
 static int ut_config_type_instance (threshold_t *th, oconfig_item_t *ci)
 {
   if ((ci->values_num != 1)
@@ -123,9 +175,8 @@ static int ut_config_type_instance (threshold_t *th, oconfig_item_t *ci)
     return (-1);
   }
 
-  strncpy (th->type_instance, ci->values[0].value.string,
+  sstrncpy (th->type_instance, ci->values[0].value.string,
       sizeof (th->type_instance));
-  th->type_instance[sizeof (th->type_instance) - 1] = '\0';
 
   return (0);
 } /* int ut_config_type_instance */
@@ -135,12 +186,15 @@ static int ut_config_type_max (threshold_t *th, oconfig_item_t *ci)
   if ((ci->values_num != 1)
       || (ci->values[0].type != OCONFIG_TYPE_NUMBER))
   {
-    WARNING ("threshold values: The `Max' option needs exactly one "
-	"number argument.");
+    WARNING ("threshold values: The `%s' option needs exactly one "
+	"number argument.", ci->key);
     return (-1);
   }
 
-  th->max = ci->values[0].value.number;
+  if (strcasecmp (ci->key, "WarningMax") == 0)
+    th->warning_max = ci->values[0].value.number;
+  else
+    th->failure_max = ci->values[0].value.number;
 
   return (0);
 } /* int ut_config_type_max */
@@ -150,12 +204,15 @@ static int ut_config_type_min (threshold_t *th, oconfig_item_t *ci)
   if ((ci->values_num != 1)
       || (ci->values[0].type != OCONFIG_TYPE_NUMBER))
   {
-    WARNING ("threshold values: The `Min' option needs exactly one "
-	"number argument.");
+    WARNING ("threshold values: The `%s' option needs exactly one "
+	"number argument.", ci->key);
     return (-1);
   }
 
-  th->min = ci->values[0].value.number;
+  if (strcasecmp (ci->key, "WarningMin") == 0)
+    th->warning_min = ci->values[0].value.number;
+  else
+    th->failure_min = ci->values[0].value.number;
 
   return (0);
 } /* int ut_config_type_min */
@@ -170,11 +227,80 @@ static int ut_config_type_invert (threshold_t *th, oconfig_item_t *ci)
     return (-1);
   }
 
-  th->invert = (ci->values[0].value.boolean) ? 1 : 0;
+  if (ci->values[0].value.boolean)
+    th->flags |= UT_FLAG_INVERT;
+  else
+    th->flags &= ~UT_FLAG_INVERT;
 
   return (0);
 } /* int ut_config_type_invert */
 
+static int ut_config_type_persist (threshold_t *th, oconfig_item_t *ci)
+{
+  if ((ci->values_num != 1)
+      || (ci->values[0].type != OCONFIG_TYPE_BOOLEAN))
+  {
+    WARNING ("threshold values: The `Persist' option needs exactly one "
+	"boolean argument.");
+    return (-1);
+  }
+
+  if (ci->values[0].value.boolean)
+    th->flags |= UT_FLAG_PERSIST;
+  else
+    th->flags &= ~UT_FLAG_PERSIST;
+
+  return (0);
+} /* int ut_config_type_persist */
+
+static int ut_config_type_percentage(threshold_t *th, oconfig_item_t *ci)
+{
+  if ((ci->values_num != 1)
+      || (ci->values[0].type != OCONFIG_TYPE_BOOLEAN))
+  {
+    WARNING ("threshold values: The `Percentage' option needs exactly one "
+	"boolean argument.");
+    return (-1);
+  }
+
+  if (ci->values[0].value.boolean)
+    th->flags |= UT_FLAG_PERCENTAGE;
+  else
+    th->flags &= ~UT_FLAG_PERCENTAGE;
+
+  return (0);
+} /* int ut_config_type_percentage */
+
+static int ut_config_type_hits (threshold_t *th, oconfig_item_t *ci)
+{
+  if ((ci->values_num != 1)
+      || (ci->values[0].type != OCONFIG_TYPE_NUMBER))
+  {
+    WARNING ("threshold values: The `%s' option needs exactly one "
+      "number argument.", ci->key);
+    return (-1);
+  }
+
+  th->hits = ci->values[0].value.number;
+
+  return (0);
+} /* int ut_config_type_hits */
+
+static int ut_config_type_hysteresis (threshold_t *th, oconfig_item_t *ci)
+{
+  if ((ci->values_num != 1)
+      || (ci->values[0].type != OCONFIG_TYPE_NUMBER))
+  {
+    WARNING ("threshold values: The `%s' option needs exactly one "
+      "number argument.", ci->key);
+    return (-1);
+  }
+
+  th->hysteresis = ci->values[0].value.number;
+
+  return (0);
+} /* int ut_config_type_hysteresis */
+
 static int ut_config_type (const threshold_t *th_orig, oconfig_item_t *ci)
 {
   int i;
@@ -196,8 +322,14 @@ static int ut_config_type (const threshold_t *th_orig, oconfig_item_t *ci)
   }
 
   memcpy (&th, th_orig, sizeof (th));
-  strncpy (th.type, ci->values[0].value.string, sizeof (th.type));
-  th.type[sizeof (th.type) - 1] = '\0';
+  sstrncpy (th.type, ci->values[0].value.string, sizeof (th.type));
+
+  th.warning_min = NAN;
+  th.warning_max = NAN;
+  th.failure_min = NAN;
+  th.failure_max = NAN;
+  th.hits = 0;
+  th.hysteresis = 0;
 
   for (i = 0; i < ci->children_num; i++)
   {
@@ -206,12 +338,24 @@ static int ut_config_type (const threshold_t *th_orig, oconfig_item_t *ci)
 
     if (strcasecmp ("Instance", option->key) == 0)
       status = ut_config_type_instance (&th, option);
-    else if (strcasecmp ("Max", option->key) == 0)
+    else if (strcasecmp ("DataSource", option->key) == 0)
+      status = ut_config_type_datasource (&th, option);
+    else if ((strcasecmp ("WarningMax", option->key) == 0)
+	|| (strcasecmp ("FailureMax", option->key) == 0))
       status = ut_config_type_max (&th, option);
-    else if (strcasecmp ("Min", option->key) == 0)
+    else if ((strcasecmp ("WarningMin", option->key) == 0)
+	|| (strcasecmp ("FailureMin", option->key) == 0))
       status = ut_config_type_min (&th, option);
     else if (strcasecmp ("Invert", option->key) == 0)
       status = ut_config_type_invert (&th, option);
+    else if (strcasecmp ("Persist", option->key) == 0)
+      status = ut_config_type_persist (&th, option);
+    else if (strcasecmp ("Percentage", option->key) == 0)
+      status = ut_config_type_percentage (&th, option);
+    else if (strcasecmp ("Hits", option->key) == 0)
+      status = ut_config_type_hits (&th, option);
+    else if (strcasecmp ("Hysteresis", option->key) == 0)
+      status = ut_config_type_hysteresis (&th, option);
     else
     {
       WARNING ("threshold values: Option `%s' not allowed inside a `Type' "
@@ -241,9 +385,8 @@ static int ut_config_plugin_instance (threshold_t *th, oconfig_item_t *ci)
     return (-1);
   }
 
-  strncpy (th->plugin_instance, ci->values[0].value.string,
+  sstrncpy (th->plugin_instance, ci->values[0].value.string,
       sizeof (th->plugin_instance));
-  th->plugin_instance[sizeof (th->plugin_instance) - 1] = '\0';
 
   return (0);
 } /* int ut_config_plugin_instance */
@@ -270,8 +413,7 @@ static int ut_config_plugin (const threshold_t *th_orig, oconfig_item_t *ci)
   }
 
   memcpy (&th, th_orig, sizeof (th));
-  strncpy (th.plugin, ci->values[0].value.string, sizeof (th.plugin));
-  th.plugin[sizeof (th.plugin) - 1] = '\0';
+  sstrncpy (th.plugin, ci->values[0].value.string, sizeof (th.plugin));
 
   for (i = 0; i < ci->children_num; i++)
   {
@@ -318,8 +460,7 @@ static int ut_config_host (const threshold_t *th_orig, oconfig_item_t *ci)
   }
 
   memcpy (&th, th_orig, sizeof (th));
-  strncpy (th.host, ci->values[0].value.string, sizeof (th.host));
-  th.host[sizeof (th.host) - 1] = '\0';
+  sstrncpy (th.host, ci->values[0].value.string, sizeof (th.host));
 
   for (i = 0; i < ci->children_num; i++)
   {
@@ -351,19 +492,31 @@ int ut_config (const oconfig_item_t *ci)
 
   threshold_t th;
 
+  if (ci->values_num != 0)
+  {
+    ERROR ("threshold values: The `Threshold' block may not have any "
+	"arguments.");
+    return (-1);
+  }
+
   if (threshold_tree == NULL)
   {
-    threshold_tree = avl_create ((void *) strcmp);
+    threshold_tree = c_avl_create ((void *) strcmp);
     if (threshold_tree == NULL)
     {
-      ERROR ("ut_config: avl_create failed.");
+      ERROR ("ut_config: c_avl_create failed.");
       return (-1);
     }
   }
 
   memset (&th, '\0', sizeof (th));
-  th.min = NAN;
-  th.max = NAN;
+  th.warning_min = NAN;
+  th.warning_max = NAN;
+  th.failure_min = NAN;
+  th.failure_max = NAN;
+
+  th.hits = 0;
+  th.hysteresis = 0;
     
   for (i = 0; i < ci->children_num; i++)
   {
@@ -393,100 +546,535 @@ int ut_config (const oconfig_item_t *ci)
  */
 /* }}} */
 
-static threshold_t *threshold_get (const char *hostname,
-    const char *plugin, const char *plugin_instance,
-    const char *type, const char *type_instance)
-{
-  char name[6 * DATA_MAX_NAME_LEN];
-  threshold_t *th = NULL;
-
-  format_name (name, sizeof (name),
-      (hostname == NULL) ? "" : hostname,
-      (plugin == NULL) ? "" : plugin, plugin_instance,
-      (type == NULL) ? "" : type, type_instance);
-  name[sizeof (name) - 1] = '\0';
-
-  if (avl_get (threshold_tree, name, (void *) &th) == 0)
-    return (th);
-  else
-    return (NULL);
-} /* threshold_t *threshold_get */
-
-static threshold_t *threshold_search (const data_set_t *ds,
-    const value_list_t *vl)
+static threshold_t *threshold_search (const value_list_t *vl)
 {
   threshold_t *th;
 
   if ((th = threshold_get (vl->host, vl->plugin, vl->plugin_instance,
-	  ds->type, vl->type_instance)) != NULL)
+	  vl->type, vl->type_instance)) != NULL)
     return (th);
   else if ((th = threshold_get (vl->host, vl->plugin, vl->plugin_instance,
-	  ds->type, NULL)) != NULL)
+	  vl->type, NULL)) != NULL)
     return (th);
   else if ((th = threshold_get (vl->host, vl->plugin, NULL,
-	  ds->type, vl->type_instance)) != NULL)
+	  vl->type, vl->type_instance)) != NULL)
     return (th);
   else if ((th = threshold_get (vl->host, vl->plugin, NULL,
-	  ds->type, NULL)) != NULL)
+	  vl->type, NULL)) != NULL)
     return (th);
   else if ((th = threshold_get (vl->host, "", NULL,
-	  ds->type, vl->type_instance)) != NULL)
+	  vl->type, vl->type_instance)) != NULL)
     return (th);
   else if ((th = threshold_get (vl->host, "", NULL,
-	  ds->type, NULL)) != NULL)
+	  vl->type, NULL)) != NULL)
     return (th);
   else if ((th = threshold_get ("", vl->plugin, vl->plugin_instance,
-	  ds->type, vl->type_instance)) != NULL)
+	  vl->type, vl->type_instance)) != NULL)
     return (th);
   else if ((th = threshold_get ("", vl->plugin, vl->plugin_instance,
-	  ds->type, NULL)) != NULL)
+	  vl->type, NULL)) != NULL)
     return (th);
   else if ((th = threshold_get ("", vl->plugin, NULL,
-	  ds->type, vl->type_instance)) != NULL)
+	  vl->type, vl->type_instance)) != NULL)
     return (th);
   else if ((th = threshold_get ("", vl->plugin, NULL,
-	  ds->type, NULL)) != NULL)
+	  vl->type, NULL)) != NULL)
     return (th);
   else if ((th = threshold_get ("", "", NULL,
-	  ds->type, vl->type_instance)) != NULL)
+	  vl->type, vl->type_instance)) != NULL)
     return (th);
   else if ((th = threshold_get ("", "", NULL,
-	  ds->type, NULL)) != NULL)
+	  vl->type, NULL)) != NULL)
     return (th);
 
   return (NULL);
 } /* threshold_t *threshold_search */
 
+/*
+ * int ut_report_state
+ *
+ * Checks if the `state' differs from the old state and creates a notification
+ * if appropriate.
+ * Does not fail.
+ */
+static int ut_report_state (const data_set_t *ds,
+    const value_list_t *vl,
+    const threshold_t *th,
+    const gauge_t *values,
+    int ds_index,
+    int state)
+{ /* {{{ */
+  int state_old;
+  notification_t n;
+
+  char *buf;
+  size_t bufsize;
+
+  int status;
+
+  /* Check if hits matched */
+  if ( (th->hits != 0) )
+  {
+    int hits = uc_get_hits(ds,vl);
+    /* The STATE_OKAY always reset hits, or if hits reaise the limit */
+    if ( (state == STATE_OKAY) || (hits > th->hits) )
+    {
+        DEBUG("ut_report_state: reset uc_get_hits = 0");
+        uc_set_hits(ds,vl,0); /* reset hit counter and notify */
+    } else {
+      DEBUG("ut_report_state: th->hits = %d, uc_get_hits = %d",th->hits,uc_get_hits(ds,vl));
+      (void) uc_inc_hits(ds,vl,1); /* increase hit counter */
+      return (0);
+    }
+  } /* end check hits */
+
+  state_old = uc_get_state (ds, vl);
+
+  /* If the state didn't change, only report if `persistent' is specified and
+   * the state is not `okay'. */
+  if (state == state_old)
+  {
+    if ((th->flags & UT_FLAG_PERSIST) == 0)
+      return (0);
+    else if (state == STATE_OKAY)
+      return (0);
+  }
+
+  if (state != state_old)
+    uc_set_state (ds, vl, state);
+
+  NOTIFICATION_INIT_VL (&n, vl, ds);
+
+  buf = n.message;
+  bufsize = sizeof (n.message);
+
+  if (state == STATE_OKAY)
+    n.severity = NOTIF_OKAY;
+  else if (state == STATE_WARNING)
+    n.severity = NOTIF_WARNING;
+  else
+    n.severity = NOTIF_FAILURE;
+
+  n.time = vl->time;
+
+  status = ssnprintf (buf, bufsize, "Host %s, plugin %s",
+      vl->host, vl->plugin);
+  buf += status;
+  bufsize -= status;
+
+  if (vl->plugin_instance[0] != '\0')
+  {
+    status = ssnprintf (buf, bufsize, " (instance %s)",
+	vl->plugin_instance);
+    buf += status;
+    bufsize -= status;
+  }
+
+  status = ssnprintf (buf, bufsize, " type %s", vl->type);
+  buf += status;
+  bufsize -= status;
+
+  if (vl->type_instance[0] != '\0')
+  {
+    status = ssnprintf (buf, bufsize, " (instance %s)",
+	vl->type_instance);
+    buf += status;
+    bufsize -= status;
+  }
+
+  plugin_notification_meta_add_string (&n, "DataSource",
+      ds->ds[ds_index].name);
+  plugin_notification_meta_add_double (&n, "CurrentValue", values[ds_index]);
+  plugin_notification_meta_add_double (&n, "WarningMin", th->warning_min);
+  plugin_notification_meta_add_double (&n, "WarningMax", th->warning_max);
+  plugin_notification_meta_add_double (&n, "FailureMin", th->failure_min);
+  plugin_notification_meta_add_double (&n, "FailureMax", th->failure_max);
+
+  /* Send an okay notification */
+  if (state == STATE_OKAY)
+  {
+    status = ssnprintf (buf, bufsize, ": All data sources are within range again.");
+    buf += status;
+    bufsize -= status;
+  }
+  else
+  {
+    double min;
+    double max;
+
+    min = (state == STATE_ERROR) ? th->failure_min : th->warning_min;
+    max = (state == STATE_ERROR) ? th->failure_max : th->warning_max;
+
+    if (th->flags & UT_FLAG_INVERT)
+    {
+      if (!isnan (min) && !isnan (max))
+      {
+        status = ssnprintf (buf, bufsize, ": Data source \"%s\" is currently "
+            "%f. That is within the %s region of %f%s and %f%s.",
+            ds->ds[ds_index].name, values[ds_index],
+            (state == STATE_ERROR) ? "failure" : "warning",
+            min, ((th->flags & UT_FLAG_PERCENTAGE) != 0) ? "%" : "",
+            max, ((th->flags & UT_FLAG_PERCENTAGE) != 0) ? "%" : "");
+      }
+      else
+      {
+	status = ssnprintf (buf, bufsize, ": Data source \"%s\" is currently "
+	    "%f. That is %s the %s threshold of %f%s.",
+	    ds->ds[ds_index].name, values[ds_index],
+	    isnan (min) ? "below" : "above",
+	    (state == STATE_ERROR) ? "failure" : "warning",
+	    isnan (min) ? max : min,
+	    ((th->flags & UT_FLAG_PERCENTAGE) != 0) ? "%" : "");
+      }
+    }
+    else if (th->flags & UT_FLAG_PERCENTAGE)
+    {
+      gauge_t value;
+      gauge_t sum;
+      int i;
+
+      sum = 0.0;
+      for (i = 0; i < vl->values_len; i++)
+      {
+        if (isnan (values[i]))
+          continue;
+
+        sum += values[i];
+      }
+
+      if (sum == 0.0)
+        value = NAN;
+      else
+        value = 100.0 * values[ds_index] / sum;
+
+      status = ssnprintf (buf, bufsize, ": Data source \"%s\" is currently "
+          "%g (%.2f%%). That is %s the %s threshold of %.2f%%.",
+          ds->ds[ds_index].name, values[ds_index], value,
+          (value < min) ? "below" : "above",
+          (state == STATE_ERROR) ? "failure" : "warning",
+          (value < min) ? min : max);
+    }
+    else /* is not inverted */
+    {
+      status = ssnprintf (buf, bufsize, ": Data source \"%s\" is currently "
+	  "%f. That is %s the %s threshold of %f.",
+	  ds->ds[ds_index].name, values[ds_index],
+	  (values[ds_index] < min) ? "below" : "above",
+	  (state == STATE_ERROR) ? "failure" : "warning",
+	  (values[ds_index] < min) ? min : max);
+    }
+    buf += status;
+    bufsize -= status;
+  }
+
+  plugin_dispatch_notification (&n);
+
+  plugin_notification_meta_free (n.meta);
+  return (0);
+} /* }}} int ut_report_state */
+
+/*
+ * int ut_check_one_data_source
+ *
+ * Checks one data source against the given threshold configuration. If the
+ * `DataSource' option is set in the threshold, and the name does NOT match,
+ * `okay' is returned. If the threshold does match, its failure and warning
+ * min and max values are checked and `failure' or `warning' is returned if
+ * appropriate.
+ * Does not fail.
+ */
+static int ut_check_one_data_source (const data_set_t *ds,
+    const value_list_t __attribute__((unused)) *vl,
+    const threshold_t *th,
+    const gauge_t *values,
+    int ds_index)
+{ /* {{{ */
+  const char *ds_name;
+  int is_warning = 0;
+  int is_failure = 0;
+  int prev_state = STATE_OKAY;
+
+  /* check if this threshold applies to this data source */
+  if (ds != NULL)
+  {
+    ds_name = ds->ds[ds_index].name;
+    if ((th->data_source[0] != 0)
+	&& (strcmp (ds_name, th->data_source) != 0))
+      return (STATE_OKAY);
+  }
+
+  if ((th->flags & UT_FLAG_INVERT) != 0)
+  {
+    is_warning--;
+    is_failure--;
+  }
+
+  /* XXX: This is an experimental code, not optimized, not fast, not reliable,
+   * and probably, do not work as you expect. Enjoy! :D */
+  if ( (th->hysteresis > 0) && ((prev_state = uc_get_state(ds,vl)) != STATE_OKAY) )
+  {
+    switch(prev_state)
+    {
+      case STATE_ERROR:
+	if ( (!isnan (th->failure_min) && ((th->failure_min + th->hysteresis) < values[ds_index])) ||
+	     (!isnan (th->failure_max) && ((th->failure_max - th->hysteresis) > values[ds_index])) )
+	  return (STATE_OKAY);
+	else
+	  is_failure++;
+      case STATE_WARNING:
+	if ( (!isnan (th->warning_min) && ((th->warning_min + th->hysteresis) < values[ds_index])) ||
+	     (!isnan (th->warning_max) && ((th->warning_max - th->hysteresis) > values[ds_index])) )
+	  return (STATE_OKAY);
+	else
+	  is_warning++;
+     }
+  }
+  else { /* no hysteresis */
+    if ((!isnan (th->failure_min) && (th->failure_min > values[ds_index]))
+	|| (!isnan (th->failure_max) && (th->failure_max < values[ds_index])))
+      is_failure++;
+
+    if ((!isnan (th->warning_min) && (th->warning_min > values[ds_index]))
+	|| (!isnan (th->warning_max) && (th->warning_max < values[ds_index])))
+      is_warning++;
+ }
+
+  if (is_failure != 0)
+    return (STATE_ERROR);
+
+  if (is_warning != 0)
+    return (STATE_WARNING);
+
+  return (STATE_OKAY);
+} /* }}} int ut_check_one_data_source */
+
+/*
+ * int ut_check_one_threshold
+ *
+ * Checks all data sources of a value list against the given threshold, using
+ * the ut_check_one_data_source function above. Returns the worst status,
+ * which is `okay' if nothing has failed.
+ * Returns less than zero if the data set doesn't have any data sources.
+ */
+static int ut_check_one_threshold (const data_set_t *ds,
+    const value_list_t *vl,
+    const threshold_t *th,
+    const gauge_t *values,
+    int *ret_ds_index)
+{ /* {{{ */
+  int ret = -1;
+  int ds_index = -1;
+  int i;
+  gauge_t values_copy[ds->ds_num];
+
+  memcpy (values_copy, values, sizeof (values_copy));
+
+  if ((th->flags & UT_FLAG_PERCENTAGE) != 0)
+  {
+    int num = 0;
+    gauge_t sum=0.0;
+
+    if (ds->ds_num == 1)
+    {
+      WARNING ("ut_check_one_threshold: The %s type has only one data "
+          "source, but you have configured to check this as a percentage. "
+          "That doesn't make much sense, because the percentage will always "
+          "be 100%%!", ds->type);
+    }
+
+    /* Prepare `sum' and `num'. */
+    for (i = 0; i < ds->ds_num; i++)
+      if (!isnan (values[i]))
+      {
+        num++;
+	sum += values[i];
+      }
+
+    if ((num == 0) /* All data sources are undefined. */
+        || (sum == 0.0)) /* Sum is zero, cannot calculate percentage. */
+    {
+      for (i = 0; i < ds->ds_num; i++)
+        values_copy[i] = NAN;
+    }
+    else /* We can actually calculate the percentage. */
+    {
+      for (i = 0; i < ds->ds_num; i++)
+        values_copy[i] = 100.0 * values[i] / sum;
+    }
+  } /* if (UT_FLAG_PERCENTAGE) */
+
+  for (i = 0; i < ds->ds_num; i++)
+  {
+    int status;
+
+    status = ut_check_one_data_source (ds, vl, th, values_copy, i);
+    if (ret < status)
+    {
+      ret = status;
+      ds_index = i;
+    }
+  } /* for (ds->ds_num) */
+
+  if (ret_ds_index != NULL)
+    *ret_ds_index = ds_index;
+
+  return (ret);
+} /* }}} int ut_check_one_threshold */
+
+/*
+ * int ut_check_threshold (PUBLIC)
+ *
+ * Gets a list of matching thresholds and searches for the worst status by one
+ * of the thresholds. Then reports that status using the ut_report_state
+ * function above. 
+ * Returns zero on success and if no threshold has been configured. Returns
+ * less than zero on failure.
+ */
 int ut_check_threshold (const data_set_t *ds, const value_list_t *vl)
-{
+{ /* {{{ */
   threshold_t *th;
   gauge_t *values;
-  int i;
+  int status;
+
+  int worst_state = -1;
+  threshold_t *worst_th = NULL;
+  int worst_ds_index = -1;
 
   if (threshold_tree == NULL)
     return (0);
+
+  /* Is this lock really necessary? So far, thresholds are only inserted at
+   * startup. -octo */
   pthread_mutex_lock (&threshold_lock);
-  th = threshold_search (ds, vl);
+  th = threshold_search (vl);
   pthread_mutex_unlock (&threshold_lock);
   if (th == NULL)
     return (0);
 
-  DEBUG ("Found matching threshold");
+  DEBUG ("ut_check_threshold: Found matching threshold(s)");
 
   values = uc_get_rate (ds, vl);
   if (values == NULL)
     return (0);
 
-  for (i = 0; i < ds->ds_num; i++)
+  while (th != NULL)
   {
-    if ((th->min > values[i]) || (th->max < values[i]))
-      WARNING ("ut_check_threshold: ds%i: %lf <= !%lf <= %lf",
-	  i, th->min, values[i], th->max);
+    int ds_index = -1;
+
+    status = ut_check_one_threshold (ds, vl, th, values, &ds_index);
+    if (status < 0)
+    {
+      ERROR ("ut_check_threshold: ut_check_one_threshold failed.");
+      sfree (values);
+      return (-1);
+    }
+
+    if (worst_state < status)
+    {
+      worst_state = status;
+      worst_th = th;
+      worst_ds_index = ds_index;
+    }
+
+    th = th->next;
+  } /* while (th) */
+
+  status = ut_report_state (ds, vl, worst_th, values,
+      worst_ds_index, worst_state);
+  if (status != 0)
+  {
+    ERROR ("ut_check_threshold: ut_report_state failed.");
+    sfree (values);
+    return (-1);
   }
 
   sfree (values);
 
   return (0);
-} /* int ut_check_threshold */
+} /* }}} int ut_check_threshold */
+
+/*
+ * int ut_check_interesting (PUBLIC)
+ *
+ * Given an identification returns
+ * 0: No threshold is defined.
+ * 1: A threshold has been found. The flag `persist' is off.
+ * 2: A threshold has been found. The flag `persist' is on.
+ *    (That is, it is expected that many notifications are sent until the
+ *    problem disappears.)
+ */
+int ut_check_interesting (const char *name)
+{ /* {{{ */
+  char *name_copy = NULL;
+  char *host = NULL;
+  char *plugin = NULL;
+  char *plugin_instance = NULL;
+  char *type = NULL;
+  char *type_instance = NULL;
+  int status;
+  data_set_t ds;
+  value_list_t vl;
+  threshold_t *th;
+
+  /* If there is no tree nothing is interesting. */
+  if (threshold_tree == NULL)
+    return (0);
+
+  name_copy = strdup (name);
+  if (name_copy == NULL)
+  {
+    ERROR ("ut_check_interesting: strdup failed.");
+    return (-1);
+  }
+
+  status = parse_identifier (name_copy, &host,
+      &plugin, &plugin_instance, &type, &type_instance);
+  if (status != 0)
+  {
+    ERROR ("ut_check_interesting: parse_identifier failed.");
+    sfree (name_copy);
+    return (-1);
+  }
+
+  memset (&ds, '\0', sizeof (ds));
+  memset (&vl, '\0', sizeof (vl));
+
+  sstrncpy (vl.host, host, sizeof (vl.host));
+  sstrncpy (vl.plugin, plugin, sizeof (vl.plugin));
+  if (plugin_instance != NULL)
+    sstrncpy (vl.plugin_instance, plugin_instance, sizeof (vl.plugin_instance));
+  sstrncpy (ds.type, type, sizeof (ds.type));
+  sstrncpy (vl.type, type, sizeof (vl.type));
+  if (type_instance != NULL)
+    sstrncpy (vl.type_instance, type_instance, sizeof (vl.type_instance));
+
+  sfree (name_copy);
+  host = plugin = plugin_instance = type = type_instance = NULL;
+
+  th = threshold_search (&vl);
+  if (th == NULL)
+    return (0);
+  if ((th->flags & UT_FLAG_PERSIST) == 0)
+    return (1);
+  return (2);
+} /* }}} int ut_check_interesting */
+
+int ut_search_threshold (const value_list_t *vl, /* {{{ */
+    threshold_t *ret_threshold)
+{
+  threshold_t *t;
+
+  if (vl == NULL)
+    return (EINVAL);
+
+  t = threshold_search (vl);
+  if (t == NULL)
+    return (ENOENT);
+
+  memcpy (ret_threshold, t, sizeof (*ret_threshold));
+  ret_threshold->next = NULL;
+
+  return (0);
+} /* }}} int ut_search_threshold */
 
-/* vim: set sw=2 ts=8 sts=2 tw=78 fdm=marker : */
+/* vim: set sw=2 ts=8 sts=2 tw=78 et fdm=marker : */