[monitoring-plugins] check_dns: returns incorrect state when ...

[Jan Wagner]

 Module: monitoring-plugins
 Branch: master
 Commit: d0da78ced184197b29af9fe910aaf56a9e7fe762
 Author: Jan Wagner <waja at cyconet.org>
   Date: Sun Sep 29 02:23:11 2013 +0200
    URL: https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=d0da78c

check_dns: returns incorrect state when specifying server

This patch verifies if the response is returned by the dns server we
are trying to check
---
Closes #981
Closes #982
Closes #1164

---

 plugins/check_dns.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/plugins/check_dns.c b/plugins/check_dns.c
index 31a953d..da90da7 100644
--- a/plugins/check_dns.c
+++ b/plugins/check_dns.c
@@ -136,6 +136,28 @@ main (int argc, char **argv)
       }
     }
 
+    /* bug ID: 2946553 - Older versions of bind will use all available dns 
+                         servers, we have to match the one specified */
+    if (strstr (chld_out.line[i], "Server:") && strlen(dns_server) > 0) {
+      temp_buffer = index (chld_out.line[i], ':');
+      temp_buffer++;
+
+      /* Strip leading tabs */
+      for (; *temp_buffer != '\0' && *temp_buffer == '\t'; temp_buffer++)
+        /* NOOP */;
+
+      strip(temp_buffer);
+      if (temp_buffer==NULL || strlen(temp_buffer)==0) {
+        die (STATE_CRITICAL,
+             _("DNS CRITICAL - '%s' returned empty server string\n"),
+             NSLOOKUP_COMMAND);
+      }
+
+      if (strcmp(temp_buffer, dns_server) != 0) {
+        die (STATE_CRITICAL, _("No response from DNS %s\n"), dns_server);
+      }
+    }
+
     /* the server is responding, we just got the host name... */
     if (strstr (chld_out.line[i], "Name:"))
       parse_address = TRUE;