src/plugin.c: Print a more verbose error message if lt_dlopen() fails.

[collectd.git] / src / plugin.c

diff --git a/src/plugin.c b/src/plugin.c
index 1eed532..492be21 100644 (file)
--- a/src/plugin.c
+++ b/src/plugin.c
@@ -279,8 +279,6 @@ static int plugin_load_file (char *file, uint32_t flags)
        lt_dlhandle dlh;
        void (*reg_handle) (void);
 
-       DEBUG ("file = %s", file);
-
        lt_dlinit ();
        lt_dlerror (); /* clear errors */
 
@@ -296,23 +294,35 @@ static int plugin_load_file (char *file, uint32_t flags)
        }
 #else /* if LIBTOOL_VERSION == 1 */
        if (flags & PLUGIN_FLAGS_GLOBAL)
-               ERROR ("plugin_load_file: The global flag is not supported, "
+               WARNING ("plugin_load_file: The global flag is not supported, "
                                "libtool 2 is required for this.");
        dlh = lt_dlopen (file);
 #endif
 
        if (dlh == NULL)
        {
-               const char *error = lt_dlerror ();
+               char errbuf[1024] = "";
+
+               ssnprintf (errbuf, sizeof (errbuf),
+                               "lt_dlopen (\"%s\") failed: %s. "
+                               "The most common cause for this problem are "
+                               "missing dependencies. Use ldd(1) to check "
+                               "the dependencies of the plugin "
+                               "/ shared object.",
+                               file, lt_dlerror ());
+
+               ERROR ("%s", errbuf);
+               /* Make sure this is printed to STDERR in any case, but also
+                * make sure it's printed only once. */
+               if (list_log != NULL)
+                       fprintf (stderr, "ERROR: %s\n", errbuf);
 
-               ERROR ("lt_dlopen (%s) failed: %s", file, error);
-               fprintf (stderr, "lt_dlopen (%s) failed: %s\n", file, error);
                return (1);
        }
 
        if ((reg_handle = (void (*) (void)) lt_dlsym (dlh, "module_register")) == NULL)
        {
-               WARNING ("Couldn't find symbol `module_register' in `%s': %s\n",
+               WARNING ("Couldn't find symbol \"module_register\" in \"%s\": %s\n",
                                file, lt_dlerror ());
                lt_dlclose (dlh);
                return (-1);
@@ -379,12 +389,15 @@ static void *plugin_read_thread (void __attribute__((unused)) *args)
                 * we need to re-evaluate the condition every time
                 * pthread_cond_timedwait returns. */
                rc = 0;
-               while (!timeout_reached(rf->rf_next_read) && rc == 0) {
+               while ((read_loop != 0)
+                               && !timeout_reached(rf->rf_next_read)
+                               && rc == 0)
+               {
                        rc = pthread_cond_timedwait (&read_cond, &read_lock,
                                &rf->rf_next_read);
                }
 
-               /* Must hold `real_lock' when accessing `rf->rf_type'. */
+               /* Must hold `read_lock' when accessing `rf->rf_type'. */
                rf_type = rf->rf_type;
                pthread_mutex_unlock (&read_lock);
 
@@ -1304,7 +1317,12 @@ int plugin_dispatch_values (value_list_t *vl)
 
        if (c_avl_get (data_sets, vl->type, (void *) &ds) != 0)
        {
-               INFO ("plugin_dispatch_values: Dataset not found: %s", vl->type);
+               char ident[6 * DATA_MAX_NAME_LEN];
+
+               FORMAT_VL (ident, sizeof (ident), vl);
+               INFO ("plugin_dispatch_values: Dataset not found: %s "
+                               "(from \"%s\"), check your types.db!",
+                               vl->type, ident);
                return (-1);
        }
 
@@ -1480,14 +1498,6 @@ void plugin_log (int level, const char *format, ...)
        va_list ap;
        llentry_t *le;
 
-       if (list_log == NULL)
-       {
-               va_start (ap, format);
-               vfprintf (stderr, format, ap);
-               va_end (ap);
-               return;
-       }
-
 #if !COLLECT_DEBUG
        if (level >= LOG_DEBUG)
                return;
@@ -1498,6 +1508,12 @@ void plugin_log (int level, const char *format, ...)
        msg[sizeof (msg) - 1] = '\0';
        va_end (ap);
 
+       if (list_log == NULL)
+       {
+               fprintf (stderr, "%s\n", msg);
+               return;
+       }
+
        le = llist_head (list_log);
        while (le != NULL)
        {