snmp plugin: Added a note about a potential bug that needs fixing.

[collectd.git] / src / snmp.c

diff --git a/src/snmp.c b/src/snmp.c
index 2026e8b..995f39d 100644 (file)
--- a/src/snmp.c
+++ b/src/snmp.c
@@ -692,6 +692,7 @@ static void csnmp_host_open_session (host_definition_t *host)
   }
 } /* void csnmp_host_open_session */
 
+/* TODO: Check if negative values wrap around. Problem: negative temperatures. */
 static value_t csnmp_value_list_to_value (struct variable_list *vl, int type,
     double scale, double shift)
 {
@@ -729,22 +730,41 @@ static value_t csnmp_value_list_to_value (struct variable_list *vl, int type,
 
   if (vl->type == ASN_OCTET_STR)
   {
-    char *string;
     char *endptr;
 
-    string = (char *) vl->val.string;
     endptr = NULL;
-
-    if (string != NULL)
+    if (vl->val.string != NULL)
     {
+      char string[64];
+      size_t string_length;
+
+      string_length = sizeof (string) - 1;
+      if (vl->val_len < string_length)
+       string_length = vl->val_len;
+
+      /* The strings we get from the Net-SNMP library may not be null
+       * terminated. That is why we're using `membpy' here and not `strcpy'.
+       * `string_length' is set to `vl->val_len' which holds the length of the
+       * string.  -octo */
+      memcpy (string, vl->val.string, string_length);
+      string[string_length] = 0;
+
       if (type == DS_TYPE_COUNTER)
+      {
        ret.counter = (counter_t) strtoll (string, &endptr, /* base = */ 0);
+       DEBUG ("snmp plugin: csnmp_value_list_to_value: String to counter: %s -> %llu",
+           string, (unsigned long long) ret.counter);
+      }
       else if (type == DS_TYPE_GAUGE)
+      {
        ret.gauge = (gauge_t) strtod (string, &endptr);
+       DEBUG ("snmp plugin: csnmp_value_list_to_value: String to gauge: %s -> %g",
+           string, (double) ret.gauge);
+      }
     }
 
     /* Check if an error occurred */
-    if ((string == NULL) || (endptr == string))
+    if ((vl->val.string == NULL) || (endptr == (char *) vl->val.string))
     {
       if (type == DS_TYPE_COUNTER)
        ret.counter = 0;
@@ -859,22 +879,15 @@ static int csnmp_instance_list_add (csnmp_list_instances_t **head,
     char *ptr;
     size_t instance_len;
 
+    memset (il->instance, 0, sizeof (il->instance));
     instance_len = sizeof (il->instance) - 1;
     if (instance_len > vb->val_len)
       instance_len = vb->val_len;
 
-    if (instance_len < 1)
-    {
-      ERROR ("snmp plugin: csnmp_instance_list_add: instance_len = %zu, "
-         "which is less than one.", instance_len);
-      sfree (il);
-      return (-1);
-    }
-
     sstrncpy (il->instance, (char *) ((vb->type == ASN_OCTET_STR)
          ? vb->val.string
          : vb->val.bitstring),
-       instance_len);
+       instance_len + 1);
 
     for (ptr = il->instance; *ptr != '\0'; ptr++)
     {
@@ -1153,10 +1166,6 @@ static int csnmp_read_table (host_definition_t *host, data_definition_t *data)
     vb = res->variables;
     if (vb == NULL)
     {
-      if (res != NULL)
-       snmp_free_pdu (res);
-      res = NULL;
-
       status = -1;
       break;
     }
@@ -1165,10 +1174,7 @@ static int csnmp_read_table (host_definition_t *host, data_definition_t *data)
      * subtree */
     if (csnmp_check_res_left_subtree (host, data, res) != 0)
     {
-      if (res != NULL)
-       snmp_free_pdu (res);
-      res = NULL;
-
+      status = 0;
       break;
     }
 
@@ -1190,11 +1196,7 @@ static int csnmp_read_table (host_definition_t *host, data_definition_t *data)
          (vb != NULL) && (vb->next_variable != NULL);
          vb = vb->next_variable)
        /* do nothing */;
-      if (vb == NULL)
-      {
-       status = -1;
-       break;
-      }
+      assert (vb != NULL);
 
       /* Copy OID to oid_list[data->values_len] */
       memcpy (oid_list[data->values_len].oid, vb->name,
@@ -1257,6 +1259,10 @@ static int csnmp_read_table (host_definition_t *host, data_definition_t *data)
     res = NULL;
   } /* while (status == 0) */
 
+  if (res != NULL)
+    snmp_free_pdu (res);
+  res = NULL;
+
   if (status == 0)
     csnmp_dispatch_table (host, data, instance_list, value_table);