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 7b30e21..492be21 100644 (file)
--- a/src/plugin.c
+++ b/src/plugin.c
@@ -151,7 +151,7 @@ static void destroy_read_heap (void) /* {{{ */
        {
                callback_func_t *cf;
 
-               cf = c_head_get_root (read_heap);
+               cf = c_heap_get_root (read_heap);
                if (cf == NULL)
                        break;
 
@@ -173,7 +173,7 @@ static int register_callback (llist_t **list, /* {{{ */
                *list = llist_create ();
                if (*list == NULL)
                {
-                       ERROR ("plugin: create_register_callback: "
+                       ERROR ("plugin: register_callback: "
                                        "llist_create failed.");
                        destroy_callback (cf);
                        return (-1);
@@ -183,7 +183,7 @@ static int register_callback (llist_t **list, /* {{{ */
        key = strdup (name);
        if (key == NULL)
        {
-               ERROR ("plugin: create_register_callback: strdup failed.");
+               ERROR ("plugin: register_callback: strdup failed.");
                destroy_callback (cf);
                return (-1);
        }
@@ -194,7 +194,7 @@ static int register_callback (llist_t **list, /* {{{ */
                le = llentry_create (key, cf);
                if (le == NULL)
                {
-                       ERROR ("plugin: create_register_callback: "
+                       ERROR ("plugin: register_callback: "
                                        "llentry_create failed.");
                        free (key);
                        destroy_callback (cf);
@@ -210,6 +210,10 @@ static int register_callback (llist_t **list, /* {{{ */
                old_cf = le->value;
                le->value = cf;
 
+               WARNING ("plugin: register_callback: "
+                               "a callback named `%s' already exists - "
+                               "overwriting the old entry!", name);
+
                destroy_callback (old_cf);
                sfree (key);
        }
@@ -275,11 +279,10 @@ 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 */
 
+#if LIBTOOL_VERSION == 2
        if (flags & PLUGIN_FLAGS_GLOBAL) {
                lt_dladvise advise;
                lt_dladvise_init(&advise);
@@ -289,18 +292,37 @@ static int plugin_load_file (char *file, uint32_t flags)
        } else {
                dlh = lt_dlopen (file);
        }
+#else /* if LIBTOOL_VERSION == 1 */
+       if (flags & PLUGIN_FLAGS_GLOBAL)
+               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);
@@ -311,6 +333,13 @@ static int plugin_load_file (char *file, uint32_t flags)
        return (0);
 }
 
+static _Bool timeout_reached(struct timespec timeout)
+{
+       struct timeval now;
+       gettimeofday(&now, NULL);
+       return (now.tv_sec >= timeout.tv_sec && now.tv_usec >= (timeout.tv_nsec / 1000));
+}
+
 static void *plugin_read_thread (void __attribute__((unused)) *args)
 {
        while (read_loop != 0)
@@ -319,9 +348,10 @@ static void *plugin_read_thread (void __attribute__((unused)) *args)
                struct timeval now;
                int status;
                int rf_type;
+               int rc;
 
                /* Get the read function that needs to be read next. */
-               rf = c_head_get_root (read_heap);
+               rf = c_heap_get_root (read_heap);
                if (rf == NULL)
                {
                        struct timespec abstime;
@@ -354,9 +384,20 @@ static void *plugin_read_thread (void __attribute__((unused)) *args)
                /* sleep until this entry is due,
                 * using pthread_cond_timedwait */
                pthread_mutex_lock (&read_lock);
-               pthread_cond_timedwait (&read_cond, &read_lock,
+               /* In pthread_cond_timedwait, spurious wakeups are possible
+                * (and really happen, at least on NetBSD with > 1 CPU), thus
+                * we need to re-evaluate the condition every time
+                * pthread_cond_timedwait returns. */
+               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);
 
@@ -1045,7 +1086,7 @@ int plugin_read_all_once (void)
        {
                read_func_t *rf;
 
-               rf = c_head_get_root (read_heap);
+               rf = c_heap_get_root (read_heap);
                if (rf == NULL)
                        break;
 
@@ -1276,7 +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);
        }
 
@@ -1452,9 +1498,6 @@ void plugin_log (int level, const char *format, ...)
        va_list ap;
        llentry_t *le;
 
-       if (list_log == NULL)
-               return;
-
 #if !COLLECT_DEBUG
        if (level >= LOG_DEBUG)
                return;
@@ -1465,6 +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)
        {