network plugin: Fix an invalid size of buffer being used.

When specifying the amount of data to copy, we used `sizeof (buffer)' where
`buffer' is a pointer, giving 4 or 8 bytes, depending on the architecture (and
not depending on the actual buffer size). This results in the `type' being sent
much more often than necessary and sometimes not sending a new type when is was
actually necessary. The only prominent case in the default configuration(s) was
`cpufreq' being used instead of `cpu', though.

While in the process, the global `type' buffer was replaced, because an
appropriate buffer is in `value_list_t' now.

Much thanks to Bruno Prémont for reporting and debugging this issue :)

References: #37

diff --git a/src/network.c b/src/network.c
index fbbcd12..9e391bb 100644 (file)
--- a/src/network.c
+++ b/src/network.c
@@ -178,7 +178,6 @@ static char         send_buffer[BUFF_SIZE];
 static char        *send_buffer_ptr;
 static int          send_buffer_fill;
 static value_list_t send_buffer_vl = VALUE_LIST_STATIC;
-static char         send_buffer_type[DATA_MAX_NAME_LEN];
 static pthread_mutex_t send_buffer_lock = PTHREAD_MUTEX_INITIALIZER;
 
 static c_avl_tree_t      *cache_tree = NULL;
@@ -1393,7 +1392,7 @@ static void network_send_buffer (const char *buffer, int buffer_len)
 } /* void network_send_buffer */
 
 static int add_to_buffer (char *buffer, int buffer_size,
-               value_list_t *vl_def, char *type_def,
+               value_list_t *vl_def,
                const data_set_t *ds, const value_list_t *vl)
 {
        char *buffer_orig = buffer;
@@ -1439,12 +1438,12 @@ static int add_to_buffer (char *buffer, int buffer_size,
                sstrncpy (vl_def->plugin_instance, vl->plugin_instance, sizeof (vl_def->plugin_instance));
        }
 
-       if (strcmp (type_def, vl->type) != 0)
+       if (strcmp (vl_def->type, vl->type) != 0)
        {
                if (write_part_string (&buffer, &buffer_size, TYPE_TYPE,
                                        vl->type, strlen (vl->type)) != 0)
                        return (-1);
-               sstrncpy (type_def, vl->type, sizeof (type_def));
+               sstrncpy (vl_def->type, ds->type, sizeof (vl_def->type));
        }
 
        if (strcmp (vl_def->type_instance, vl->type_instance) != 0)
@@ -1470,8 +1469,7 @@ static void flush_buffer (void)
        network_send_buffer (send_buffer, send_buffer_fill);
        send_buffer_ptr  = send_buffer;
        send_buffer_fill = 0;
-       memset (&send_buffer_vl, '\0', sizeof (send_buffer_vl));
-       memset (send_buffer_type, '\0', sizeof (send_buffer_type));
+       memset (&send_buffer_vl, 0, sizeof (send_buffer_vl));
 }
 
 static int network_write (const data_set_t *ds, const value_list_t *vl)
@@ -1490,7 +1488,7 @@ static int network_write (const data_set_t *ds, const value_list_t *vl)
 
        status = add_to_buffer (send_buffer_ptr,
                        sizeof (send_buffer) - send_buffer_fill,
-                       &send_buffer_vl, send_buffer_type,
+                       &send_buffer_vl,
                        ds, vl);
        if (status >= 0)
        {
@@ -1504,7 +1502,7 @@ static int network_write (const data_set_t *ds, const value_list_t *vl)
 
                status = add_to_buffer (send_buffer_ptr,
                                sizeof (send_buffer) - send_buffer_fill,
-                               &send_buffer_vl, send_buffer_type,
+                               &send_buffer_vl,
                                ds, vl);
 
                if (status >= 0)
@@ -1726,8 +1724,7 @@ static int network_init (void)
 
        send_buffer_ptr  = send_buffer;
        send_buffer_fill = 0;
-       memset (&send_buffer_vl, '\0', sizeof (send_buffer_vl));
-       memset (send_buffer_type, '\0', sizeof (send_buffer_type));
+       memset (&send_buffer_vl, 0, sizeof (send_buffer_vl));
 
        cache_tree = c_avl_create ((int (*) (const void *, const void *)) strcmp);
        cache_flush_last = time (NULL);