From 6a5004f9c4394c8f561ba3b817196e7a50ad7237 Mon Sep 17 00:00:00 2001
From: Florian Forster <octo@collectd.org>
Date: Fri, 11 Jan 2013 19:45:43 +0100
Subject: [PATCH] ethstat plugin: Fix the map lookup.

Previously, a pointer into the configuration structure was used to look
up the mappings. Because the configuration structure is freed or
otherwise modified, this does not work as intended (and may actually
lead to a segmentation fault when unlucky).

For completeness sake, a shutdown callback was added to free the used
memory on exit.

Fixes Github issue 224.
---
 src/ethstat.c | 43 +++++++++++++++++++++++++++++++++++++------
 1 file changed, 37 insertions(+), 6 deletions(-)

diff --git a/src/ethstat.c b/src/ethstat.c
index 08381a82..ee6979c5 100644
--- a/src/ethstat.c
+++ b/src/ethstat.c
@@ -83,6 +83,7 @@ static int ethstat_add_map (const oconfig_item_t *ci) /* {{{ */
 {
   value_map_t *map;
   int status;
+  char *key;
 
   if ((ci->values_num < 2)
       || (ci->values_num > 3)
@@ -96,9 +97,17 @@ static int ethstat_add_map (const oconfig_item_t *ci) /* {{{ */
     return (-1);
   }
 
+  key = strdup (ci->values[0].value.string);
+  if (key == NULL)
+  {
+    ERROR ("ethstat plugin: strdup(3) failed.");
+    return (ENOMEM);
+  }
+
   map = malloc (sizeof (*map));
   if (map == NULL)
   {
+    sfree (key);
     ERROR ("ethstat plugin: malloc(3) failed.");
     return (ENOMEM);
   }
@@ -115,23 +124,24 @@ static int ethstat_add_map (const oconfig_item_t *ci) /* {{{ */
     if (value_map == NULL)
     {
       sfree (map);
+      sfree (key);
       ERROR ("ethstat plugin: c_avl_create() failed.");
       return (-1);
     }
   }
 
   status = c_avl_insert (value_map,
-      /* key = */ ci->values[0].value.string,
+      /* key = */ key,
       /* value = */ map);
   if (status != 0)
   {
-    sfree (map);
     if (status > 0)
-      ERROR ("ethstat plugin: Multiple mappings for \"%s\".",
-          ci->values[0].value.string);
+      ERROR ("ethstat plugin: Multiple mappings for \"%s\".", key);
     else
-      ERROR ("ethstat plugin: c_avl_insert(\"%s\") failed.",
-          ci->values[0].value.string);
+      ERROR ("ethstat plugin: c_avl_insert(\"%s\") failed.", key);
+
+    sfree (map);
+    sfree (key);
     return (-1);
   }
 
@@ -328,10 +338,31 @@ static int ethstat_read(void)
   return 0;
 }
 
+static int ethstat_shutdown (void)
+{
+  void *key = NULL;
+  void *value = NULL;
+
+  if (value_map == NULL)
+    return (0);
+
+  while (c_avl_pick (value_map, &key, &value) == 0)
+  {
+    sfree (key);
+    sfree (value);
+  }
+
+  c_avl_destroy (value_map);
+  value_map = NULL;
+
+  return (0);
+}
+
 void module_register (void)
 {
   plugin_register_complex_config ("ethstat", ethstat_config);
   plugin_register_read ("ethstat", ethstat_read);
+  plugin_register_shutdown ("ethstat", ethstat_shutdown);
 }
 
 /* vim: set sw=2 sts=2 et fdm=marker : */
-- 
2.11.0