apcups plugin polling issues when non-default interval used

[octo]

From: Edwin (Mantis #38)

Description: Using collectd 4.10.1-2 (Ubuntu 10.10 Maverick repo)

When changing the collectd interval to 30, apcups plugin always fails polling after the initial poll succeeds. This causes the plugin to be paused and stats not collected.

Syslog entries will look something like:

Jun 15 14:55:28 codis collectd[2607]: apcups plugin: Writing to the socket failed.
Jun 15 14:55:28 codis collectd[2607]: read-function of plugin `apcups' failed. Will suspend it for 60 seconds.
Jun 15 14:56:58 codis collectd[2607]: apcups plugin: Writing to the socket failed.
Jun 15 14:56:58 codis collectd[2607]: read-function of plugin `apcups' failed. Will suspend it for 60 seconds.

Steps To Reproduce: Change collectd interval to 30

Additional Information: This appears to be due to attempting to reuse the network socket and not handling any failures. Workaround is to open a new socket each time.

Patch attached to close the socket everytime. Cleaner patch should probably attempt to reuse the socket if possible and then open a new one on error.

--- apcups.c.orig       2011-06-16 09:56:52.231552800 -0400
+++ apcups.c    2011-06-16 09:56:56.690889806 -0400
@@ -323,6 +323,18 @@
                return (-1);
        }

+       uint16_t packet_size = 0;
+        if (global_sockfd < 0)
+                return (0);
+
+        DEBUG ("Gracefully shutting down socket %i.", global_sockfd);
+
+        /* send EOF sentinel */
+        swrite (global_sockfd, (void *) &packet_size, sizeof (packet_size));
+
+        close (global_sockfd);
+        global_sockfd = -1;
+
        return (0);
 }