sensors plugin: Reload lm_sensors' configuration when changed

Signed-off-by: Stanek Lubos <kolektor@atlas.cz>

diff --git a/src/sensors.c b/src/sensors.c
index 6ba8154..7c05b7a 100644 (file)
--- a/src/sensors.c
+++ b/src/sensors.c
@@ -185,6 +185,12 @@ static int sensor_extended_naming = 0;
 static const char *conffile = SENSORS_CONF_PATH;
 /* SENSORS_CONF_PATH */
 
+/*
+ * remember stat of the loaded config
+ */
+static struct stat sensors_conf_stat;
+static int sensors_conf_loaded = 0;
+
 typedef struct featurelist
 {
        const sensors_chip_name    *chip;
@@ -234,9 +240,28 @@ static int sensors_config (char *key, char *value)
        return (0);
 }
 
-static void collectd_sensors_init (void)
-{
 #if SENSORS_HAVE_READ
+void sensors_free_features (void)
+{
+       featurelist_t *thisft;
+       featurelist_t *nextft;
+
+       if (sensors_conf_loaded)
+       {
+               sensors_cleanup ();
+               sensors_conf_loaded = 0;
+       }
+
+       for (thisft = first_feature; thisft != NULL; thisft = nextft)
+       {
+               nextft = thisft->next;
+               sfree (thisft);
+       }
+       first_feature = NULL;
+}
+
+static void sensors_load_conf (int firsttime)
+{
        FILE *fh;
        featurelist_t *last_feature = NULL;
        featurelist_t *new_feature;
@@ -247,13 +272,8 @@ static void collectd_sensors_init (void)
        const sensors_feature_data *data;
        int data_num0, data_num1;
        
+       sensors_free_features ();
        new_feature = first_feature;
-       while (new_feature != NULL)
-       {
-               last_feature = new_feature->next;
-               free (new_feature);
-               new_feature = last_feature;
-       }
 
 #ifdef assert
        assert (new_feature == NULL);
@@ -261,7 +281,11 @@ static void collectd_sensors_init (void)
 #endif
 
        if ((fh = fopen (conffile, "r")) == NULL)
+       {
+               syslog (LOG_ERR, MODULE_NAME": cannot open %s: %s. "
+                               "Data will not be collected.", conffile, strerror(errno));
                return;
+       }
 
        if (sensors_init (fh))
        {
@@ -271,6 +295,15 @@ static void collectd_sensors_init (void)
                return;
        }
 
+       /* remember file status to detect changes */
+       if (fstat (fileno (fh), &sensors_conf_stat) == -1)
+       {
+               fclose (fh);
+               syslog (LOG_ERR, MODULE_NAME": cannot fstat %s: %s "
+                               "Data will not be collected.", conffile, strerror(errno));
+               return;
+       }
+
        fclose (fh);
 
        chip_num = 0;
@@ -333,27 +366,32 @@ static void collectd_sensors_init (void)
                } /* while sensors_get_all_features */
        } /* while sensors_get_detected_chips */
 
+       if (!firsttime)
+               syslog (LOG_INFO, MODULE_NAME": lm_sensors' configuration reloaded.");
+
        if (first_feature == NULL)
+       {
                sensors_cleanup ();
+               sensors_conf_loaded = 0;
+               syslog (LOG_INFO, MODULE_NAME": lm_sensors reports no features. "
+                       "Data will not be collected.");
+       }
+       else
+               sensors_conf_loaded = 1;
+}
 #endif /* if SENSORS_HAVE_READ */
 
-       return;
+static void collectd_sensors_init (void)
+{
+#if SENSORS_HAVE_READ
+       sensors_load_conf (1);
+#endif /* if SENSORS_HAVE_READ */
 }
 
 static void sensors_shutdown (void)
 {
 #if SENSORS_HAVE_READ
-       featurelist_t *thisft = first_feature;
-       featurelist_t *nextft;
-
-       while (thisft != NULL)
-       {
-               nextft = thisft->next;
-               sfree (thisft);
-               thisft = nextft;
-       }
-
-       sensors_cleanup ();
+       sensors_free_features ();
 #endif /* if SENSORS_HAVE_READ */
 
        ignorelist_free (sensor_list);
@@ -439,6 +477,31 @@ static void sensors_read (void)
        featurelist_t *feature;
        double value;
        char chip_fullprefix[BUFSIZE];
+       struct stat changedbuf;
+
+       /* check sensors.conf for changes */
+       if (sensors_conf_loaded)
+       {
+               if (stat (conffile, &changedbuf) == -1)
+               {
+                       syslog (LOG_ERR, MODULE_NAME": cannot stat %s: %s",
+                                       conffile, strerror(errno));
+                       /*
+                        * sensors.conf does not exist,
+                        * throw away previous conf
+                        */
+                       sensors_load_conf (0);
+               }
+               else
+               {
+                       if ((changedbuf.st_size != sensors_conf_stat.st_size) ||
+                                       (changedbuf.st_mtime != sensors_conf_stat.st_mtime) ||
+                                       (changedbuf.st_ino != sensors_conf_stat.st_ino))
+                       {
+                               sensors_load_conf (0);
+                       }
+               }
+       }
 
        for (feature = first_feature; feature != NULL; feature = feature->next)
        {