dns plugin: Sleep for an interval before re-trying to read from interface.

Otherwise we'd just have the CPU hogging behavior shifted from libpcap
to collectd …

Github: #308

diff --git a/src/dns.c b/src/dns.c
index aea41c438de44430d35236aec0ec7d9d9a9c4d7a..00fcff191e0ccf0177ec7bea309eb2964b331228 100644 (file)
--- a/src/dns.c
+++ b/src/dns.c
@@ -275,12 +275,47 @@ static int dns_run_pcap_loop (void)
        return (status);
 } /* int dns_run_pcap_loop */
 
+static int dns_sleep_one_interval (void) /* {{{ */
+{
+       cdtime_t interval;
+       struct timespec ts = { 0, 0 };
+       int status = 0;
+
+       interval = plugin_get_interval ();
+       CDTIME_T_TO_TIMESPEC (interval, &ts);
+
+       while (42)
+       {
+               struct timespec rem = { 0, 0 };
+
+               status = nanosleep (&ts, &rem);
+               if (status == 0)
+                       break;
+               else if ((errno == EINTR) || (errno == EAGAIN))
+               {
+                       ts = rem;
+                       continue;
+               }
+               else
+                       break;
+       }
+
+       return (status);
+} /* }}} int dns_sleep_one_interval */
+
 static void *dns_child_loop (__attribute__((unused)) void *dummy) /* {{{ */
 {
-       int status = PCAP_ERROR_IFACE_NOT_UP;
+       int status;
 
-       while (status == PCAP_ERROR_IFACE_NOT_UP)
+       while (42)
+       {
                status = dns_run_pcap_loop ();
+               if (status != PCAP_ERROR_IFACE_NOT_UP)
+                       break;
+
+               dns_sleep_one_interval ();
+       }
+
        if (status != PCAP_ERROR_BREAK)
                ERROR ("dns plugin: PCAP returned error %s.",
                                pcap_statustostr (status));