X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=src%2Fperl.c;h=4daa7621e4bec0d0c89103aa6f94eb452a9d9e76;hb=82f6ebad0250c0b8cd0cdf7453fe427fd7b38135;hp=c0326943298837d42741afb9acb65276081fa6b2;hpb=34a35d78bb0ec655f9b8cf6f464fedbe2877470b;p=collectd.git

diff --git a/src/perl.c b/src/perl.c
index c0326943..4daa7621 100644
--- a/src/perl.c
+++ b/src/perl.c
@@ -1,6 +1,6 @@
-/**
+/*
  * collectd - src/perl.c
- * Copyright (C) 2007, 2008  Sebastian Harl
+ * Copyright (C) 2007-2009  Sebastian Harl
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
@@ -51,6 +51,8 @@
 #include "plugin.h"
 #include "common.h"
 
+#include "filter_chain.h"
+
 #include <pthread.h>
 
 #if !defined(USE_ITHREADS)
@@ -74,6 +76,17 @@
 #define PLUGIN_CONFIG   254
 #define PLUGIN_DATASET  255
 
+#define FC_MATCH  0
+#define FC_TARGET 1
+
+#define FC_TYPES  2
+
+#define FC_CB_CREATE  0
+#define FC_CB_DESTROY 1
+#define FC_CB_EXEC    2
+
+#define FC_CB_TYPES   3
+
 #define log_debug(...) DEBUG ("perl: " __VA_ARGS__)
 #define log_info(...) INFO ("perl: " __VA_ARGS__)
 #define log_warn(...) WARNING ("perl: " __VA_ARGS__)
@@ -85,9 +98,11 @@ void boot_DynaLoader (PerlInterpreter *, CV *);
 static XS (Collectd_plugin_register_ds);
 static XS (Collectd_plugin_unregister_ds);
 static XS (Collectd_plugin_dispatch_values);
+static XS (Collectd__plugin_write);
 static XS (Collectd__plugin_flush);
 static XS (Collectd_plugin_dispatch_notification);
 static XS (Collectd_plugin_log);
+static XS (Collectd__fc_register);
 static XS (Collectd_call_by_name);
 
 /*
@@ -115,6 +130,25 @@ typedef struct {
 	pthread_mutex_t mutex;
 } c_ithread_list_t;
 
+/* name / user_data for Perl matches / targets */
+typedef struct {
+	char *name;
+	SV   *user_data;
+} pfc_user_data_t;
+
+#define PFC_USER_DATA_FREE(data) \
+	do { \
+		sfree ((data)->name); \
+		if (NULL != (data)->user_data) \
+			sv_free ((data)->user_data); \
+		sfree (data); \
+	} while (0)
+
+/*
+ * Public variable
+ */
+extern char **environ;
+
 /*
  * private variables
  */
@@ -139,10 +173,12 @@ static struct {
 	{ "Collectd::plugin_register_data_set",   Collectd_plugin_register_ds },
 	{ "Collectd::plugin_unregister_data_set", Collectd_plugin_unregister_ds },
 	{ "Collectd::plugin_dispatch_values",     Collectd_plugin_dispatch_values },
+	{ "Collectd::_plugin_write",              Collectd__plugin_write },
 	{ "Collectd::_plugin_flush",              Collectd__plugin_flush },
 	{ "Collectd::plugin_dispatch_notification",
 		Collectd_plugin_dispatch_notification },
 	{ "Collectd::plugin_log",                 Collectd_plugin_log },
+	{ "Collectd::_fc_register",               Collectd__fc_register },
 	{ "Collectd::call_by_name",               Collectd_call_by_name },
 	{ "", NULL }
 };
@@ -152,25 +188,37 @@ struct {
 	int  value;
 } constants[] =
 {
-	{ "Collectd::TYPE_INIT",       PLUGIN_INIT },
-	{ "Collectd::TYPE_READ",       PLUGIN_READ },
-	{ "Collectd::TYPE_WRITE",      PLUGIN_WRITE },
-	{ "Collectd::TYPE_SHUTDOWN",   PLUGIN_SHUTDOWN },
-	{ "Collectd::TYPE_LOG",        PLUGIN_LOG },
-	{ "Collectd::TYPE_NOTIF",      PLUGIN_NOTIF },
-	{ "Collectd::TYPE_FLUSH",      PLUGIN_FLUSH },
-	{ "Collectd::TYPE_CONFIG",     PLUGIN_CONFIG },
-	{ "Collectd::TYPE_DATASET",    PLUGIN_DATASET },
-	{ "Collectd::DS_TYPE_COUNTER", DS_TYPE_COUNTER },
-	{ "Collectd::DS_TYPE_GAUGE",   DS_TYPE_GAUGE },
-	{ "Collectd::LOG_ERR",         LOG_ERR },
-	{ "Collectd::LOG_WARNING",     LOG_WARNING },
-	{ "Collectd::LOG_NOTICE",      LOG_NOTICE },
-	{ "Collectd::LOG_INFO",        LOG_INFO },
-	{ "Collectd::LOG_DEBUG",       LOG_DEBUG },
-	{ "Collectd::NOTIF_FAILURE",   NOTIF_FAILURE },
-	{ "Collectd::NOTIF_WARNING",   NOTIF_WARNING },
-	{ "Collectd::NOTIF_OKAY",      NOTIF_OKAY },
+	{ "Collectd::TYPE_INIT",          PLUGIN_INIT },
+	{ "Collectd::TYPE_READ",          PLUGIN_READ },
+	{ "Collectd::TYPE_WRITE",         PLUGIN_WRITE },
+	{ "Collectd::TYPE_SHUTDOWN",      PLUGIN_SHUTDOWN },
+	{ "Collectd::TYPE_LOG",           PLUGIN_LOG },
+	{ "Collectd::TYPE_NOTIF",         PLUGIN_NOTIF },
+	{ "Collectd::TYPE_FLUSH",         PLUGIN_FLUSH },
+	{ "Collectd::TYPE_CONFIG",        PLUGIN_CONFIG },
+	{ "Collectd::TYPE_DATASET",       PLUGIN_DATASET },
+	{ "Collectd::DS_TYPE_COUNTER",    DS_TYPE_COUNTER },
+	{ "Collectd::DS_TYPE_GAUGE",      DS_TYPE_GAUGE },
+	{ "Collectd::DS_TYPE_DERIVE",     DS_TYPE_DERIVE },
+	{ "Collectd::DS_TYPE_ABSOLUTE",   DS_TYPE_ABSOLUTE },
+	{ "Collectd::LOG_ERR",            LOG_ERR },
+	{ "Collectd::LOG_WARNING",        LOG_WARNING },
+	{ "Collectd::LOG_NOTICE",         LOG_NOTICE },
+	{ "Collectd::LOG_INFO",           LOG_INFO },
+	{ "Collectd::LOG_DEBUG",          LOG_DEBUG },
+	{ "Collectd::FC_MATCH",           FC_MATCH },
+	{ "Collectd::FC_TARGET",          FC_TARGET },
+	{ "Collectd::FC_CB_CREATE",       FC_CB_CREATE },
+	{ "Collectd::FC_CB_DESTROY",      FC_CB_DESTROY },
+	{ "Collectd::FC_CB_EXEC",         FC_CB_EXEC },
+	{ "Collectd::FC_MATCH_NO_MATCH",  FC_MATCH_NO_MATCH },
+	{ "Collectd::FC_MATCH_MATCHES",   FC_MATCH_MATCHES },
+	{ "Collectd::FC_TARGET_CONTINUE", FC_TARGET_CONTINUE },
+	{ "Collectd::FC_TARGET_STOP",     FC_TARGET_STOP },
+	{ "Collectd::FC_TARGET_RETURN",   FC_TARGET_RETURN },
+	{ "Collectd::NOTIF_FAILURE",      NOTIF_FAILURE },
+	{ "Collectd::NOTIF_WARNING",      NOTIF_WARNING },
+	{ "Collectd::NOTIF_OKAY",         NOTIF_OKAY },
 	{ "", 0 }
 };
 
@@ -226,7 +274,10 @@ static int hv2data_source (pTHX_ HV *hash, data_source_t *ds)
 	if (NULL != (tmp = hv_fetch (hash, "type", 4, 0))) {
 		ds->type = SvIV (*tmp);
 
-		if ((DS_TYPE_COUNTER != ds->type) && (DS_TYPE_GAUGE != ds->type)) {
+		if ((DS_TYPE_COUNTER != ds->type)
+				&& (DS_TYPE_GAUGE != ds->type)
+				&& (DS_TYPE_DERIVE != ds->type)
+				&& (DS_TYPE_ABSOLUTE != ds->type)) {
 			log_err ("hv2data_source: Invalid DS type.");
 			return -1;
 		}
@@ -279,8 +330,12 @@ static int av2value (pTHX_ char *name, AV *array, value_t *value, int len)
 		if (NULL != tmp) {
 			if (DS_TYPE_COUNTER == ds->ds[i].type)
 				value[i].counter = SvIV (*tmp);
-			else
+			else if (DS_TYPE_GAUGE == ds->ds[i].type)
 				value[i].gauge = SvNV (*tmp);
+			else if (DS_TYPE_DERIVE == ds->ds[i].type)
+				value[i].derive = SvIV (*tmp);
+			else if (DS_TYPE_ABSOLUTE == ds->ds[i].type)
+				value[i].absolute = SvIV (*tmp);
 		}
 		else {
 			return -1;
@@ -337,16 +392,16 @@ static int hv2value_list (pTHX_ HV *hash, value_list_t *vl)
 		}
 	}
 
-	if (NULL != (tmp = hv_fetch (hash, "time", 4, 0))) {
+	if (NULL != (tmp = hv_fetch (hash, "time", 4, 0)))
 		vl->time = (time_t)SvIV (*tmp);
-	}
 
-	if (NULL != (tmp = hv_fetch (hash, "host", 4, 0))) {
+	if (NULL != (tmp = hv_fetch (hash, "interval", 8, 0)))
+		vl->interval = SvIV (*tmp);
+
+	if (NULL != (tmp = hv_fetch (hash, "host", 4, 0)))
 		sstrncpy (vl->host, SvPV_nolen (*tmp), sizeof (vl->host));
-	}
-	else {
+	else
 		sstrncpy (vl->host, hostname_g, sizeof (vl->host));
-	}
 
 	if (NULL != (tmp = hv_fetch (hash, "plugin", 6, 0)))
 		sstrncpy (vl->plugin, SvPV_nolen (*tmp), sizeof (vl->plugin));
@@ -403,6 +458,139 @@ static int av2data_set (pTHX_ AV *array, char *name, data_set_t *ds)
 	return 0;
 } /* static int av2data_set (pTHX_ AV *, data_set_t *) */
 
+/*
+ * notification:
+ * {
+ *   severity => $severity,
+ *   time     => $time,
+ *   message  => $msg,
+ *   host     => $host,
+ *   plugin   => $plugin,
+ *   type     => $type,
+ *   plugin_instance => $instance,
+ *   type_instance   => $type_instance,
+ *   meta     => [ { name => <name>, value => <value> }, ... ]
+ * }
+ */
+static int av2notification_meta (pTHX_ AV *array, notification_meta_t **meta)
+{
+	notification_meta_t **m = meta;
+
+	int len = av_len (array);
+	int i;
+
+	for (i = 0; i <= len; ++i) {
+		SV **tmp = av_fetch (array, i, 0);
+		HV  *hash;
+
+		if (NULL == tmp)
+			return -1;
+
+		if (! (SvROK (*tmp) && (SVt_PVHV == SvTYPE (SvRV (*tmp))))) {
+			log_warn ("av2notification_meta: Skipping invalid "
+					"meta information.");
+			continue;
+		}
+
+		hash = (HV *)SvRV (*tmp);
+
+		*m = (notification_meta_t *)smalloc (sizeof (**m));
+
+		if (NULL == (tmp = hv_fetch (hash, "name", 4, 0))) {
+			log_warn ("av2notification_meta: Skipping invalid "
+					"meta information.");
+			free (*m);
+			continue;
+		}
+		sstrncpy ((*m)->name, SvPV_nolen (*tmp), sizeof ((*m)->name));
+
+		if (NULL == (tmp = hv_fetch (hash, "value", 5, 0))) {
+			log_warn ("av2notification_meta: Skipping invalid "
+					"meta information.");
+			free ((*m)->name);
+			free (*m);
+			continue;
+		}
+
+		if (SvNOK (*tmp)) {
+			(*m)->nm_value.nm_double = SvNVX (*tmp);
+			(*m)->type = NM_TYPE_DOUBLE;
+		}
+		else if (SvUOK (*tmp)) {
+			(*m)->nm_value.nm_unsigned_int = SvUVX (*tmp);
+			(*m)->type = NM_TYPE_UNSIGNED_INT;
+		}
+		else if (SvIOK (*tmp)) {
+			(*m)->nm_value.nm_signed_int = SvIVX (*tmp);
+			(*m)->type = NM_TYPE_SIGNED_INT;
+		}
+		else {
+			(*m)->nm_value.nm_string = sstrdup (SvPV_nolen (*tmp));
+			(*m)->type = NM_TYPE_STRING;
+		}
+
+		(*m)->next = NULL;
+		m = &((*m)->next);
+	}
+	return 0;
+} /* static int av2notification_meta (AV *, notification_meta_t *) */
+
+static int hv2notification (pTHX_ HV *hash, notification_t *n)
+{
+	SV **tmp = NULL;
+
+	if ((NULL == hash) || (NULL == n))
+		return -1;
+
+	if (NULL != (tmp = hv_fetch (hash, "severity", 8, 0)))
+		n->severity = SvIV (*tmp);
+	else
+		n->severity = NOTIF_FAILURE;
+
+	if (NULL != (tmp = hv_fetch (hash, "time", 4, 0)))
+		n->time = (time_t)SvIV (*tmp);
+	else
+		n->time = time (NULL);
+
+	if (NULL != (tmp = hv_fetch (hash, "message", 7, 0)))
+		sstrncpy (n->message, SvPV_nolen (*tmp), sizeof (n->message));
+
+	if (NULL != (tmp = hv_fetch (hash, "host", 4, 0)))
+		sstrncpy (n->host, SvPV_nolen (*tmp), sizeof (n->host));
+	else
+		sstrncpy (n->host, hostname_g, sizeof (n->host));
+
+	if (NULL != (tmp = hv_fetch (hash, "plugin", 6, 0)))
+		sstrncpy (n->plugin, SvPV_nolen (*tmp), sizeof (n->plugin));
+
+	if (NULL != (tmp = hv_fetch (hash, "plugin_instance", 15, 0)))
+		sstrncpy (n->plugin_instance, SvPV_nolen (*tmp),
+				sizeof (n->plugin_instance));
+
+	if (NULL != (tmp = hv_fetch (hash, "type", 4, 0)))
+		sstrncpy (n->type, SvPV_nolen (*tmp), sizeof (n->type));
+
+	if (NULL != (tmp = hv_fetch (hash, "type_instance", 13, 0)))
+		sstrncpy (n->type_instance, SvPV_nolen (*tmp),
+				sizeof (n->type_instance));
+
+	n->meta = NULL;
+	while (NULL != (tmp = hv_fetch (hash, "meta", 4, 0))) {
+		if (! (SvROK (*tmp) && (SVt_PVAV == SvTYPE (SvRV (*tmp))))) {
+			log_warn ("hv2notification: Ignoring invalid meta information.");
+			break;
+		}
+
+		if (0 != av2notification_meta (aTHX_ (AV *)SvRV (*tmp), &n->meta)) {
+			plugin_notification_meta_free (n->meta);
+			n->meta = NULL;
+			return -1;
+		}
+		break;
+	}
+	return 0;
+} /* static int hv2notification (pTHX_ HV *, notification_t *) */
+
 static int data_set2av (pTHX_ data_set_t *ds, AV *array)
 {
 	int i = 0;
@@ -463,8 +651,12 @@ static int value_list2hv (pTHX_ value_list_t *vl, data_set_t *ds, HV *hash)
 
 		if (DS_TYPE_COUNTER == ds->ds[i].type)
 			val = newSViv (vl->values[i].counter);
-		else
+		else if (DS_TYPE_GAUGE == ds->ds[i].type)
 			val = newSVnv (vl->values[i].gauge);
+		else if (DS_TYPE_DERIVE == ds->ds[i].type)
+			val = newSViv (vl->values[i].derive);
+		else if (DS_TYPE_ABSOLUTE == ds->ds[i].type)
+			val = newSViv (vl->values[i].absolute);
 
 		if (NULL == av_store (values, i, val)) {
 			av_undef (values);
@@ -479,6 +671,9 @@ static int value_list2hv (pTHX_ value_list_t *vl, data_set_t *ds, HV *hash)
 		if (NULL == hv_store (hash, "time", 4, newSViv (vl->time), 0))
 			return -1;
 
+	if (NULL == hv_store (hash, "interval", 8, newSViv (vl->interval), 0))
+		return -1;
+
 	if ('\0' != vl->host[0])
 		if (NULL == hv_store (hash, "host", 4, newSVpv (vl->host, 0), 0))
 			return -1;
@@ -503,6 +698,52 @@ static int value_list2hv (pTHX_ value_list_t *vl, data_set_t *ds, HV *hash)
 	return 0;
 } /* static int value2av (value_list_t *, data_set_t *, HV *) */
 
+static int notification_meta2av (pTHX_ notification_meta_t *meta, AV *array)
+{
+	int meta_num = 0;
+	int i;
+
+	while (meta) {
+		++meta_num;
+		meta = meta->next;
+	}
+
+	av_extend (array, meta_num);
+
+	for (i = 0; NULL != meta; meta = meta->next, ++i) {
+		HV *m = newHV ();
+		SV *value;
+
+		if (NULL == hv_store (m, "name", 4, newSVpv (meta->name, 0), 0))
+			return -1;
+
+		if (NM_TYPE_STRING == meta->type)
+			value = newSVpv (meta->nm_value.nm_string, 0);
+		else if (NM_TYPE_SIGNED_INT == meta->type)
+			value = newSViv (meta->nm_value.nm_signed_int);
+		else if (NM_TYPE_UNSIGNED_INT == meta->type)
+			value = newSVuv (meta->nm_value.nm_unsigned_int);
+		else if (NM_TYPE_DOUBLE == meta->type)
+			value = newSVnv (meta->nm_value.nm_double);
+		else if (NM_TYPE_BOOLEAN == meta->type)
+			value = meta->nm_value.nm_boolean ? &PL_sv_yes : &PL_sv_no;
+		else
+			return -1;
+
+		if (NULL == hv_store (m, "value", 5, value, 0)) {
+			sv_free (value);
+			return -1;
+		}
+
+		if (NULL == av_store (array, i, newRV_noinc ((SV *)m))) {
+			hv_clear (m);
+			hv_undef (m);
+			return -1;
+		}
+	}
+	return 0;
+} /* static int notification_meta2av (notification_meta_t *, AV *) */
+
 static int notification2hv (pTHX_ notification_t *n, HV *hash)
 {
 	if (NULL == hv_store (hash, "severity", 8, newSViv (n->severity), 0))
@@ -537,6 +778,17 @@ static int notification2hv (pTHX_ notification_t *n, HV *hash)
 		if (NULL == hv_store (hash, "type_instance", 13,
 				newSVpv (n->type_instance, 0), 0))
 			return -1;
+
+	if (NULL != n->meta) {
+		AV *meta = newAV ();
+		if ((0 != notification_meta2av (aTHX_ n->meta, meta))
+				|| (NULL == hv_store (hash, "meta", 4,
+						newRV_noinc ((SV *)meta), 0))) {
+			av_clear (meta);
+			av_undef (meta);
+			return -1;
+		}
+	}
 	return 0;
 } /* static int notification2hv (notification_t *, HV *) */
 
@@ -683,62 +935,56 @@ static int pplugin_dispatch_values (pTHX_ HV *values)
 } /* static int pplugin_dispatch_values (char *, HV *) */
 
 /*
- * Dispatch a notification.
- *
- * notification:
- * {
- *   severity => $severity,
- *   time     => $time,
- *   message  => $msg,
- *   host     => $host,
- *   plugin   => $plugin,
- *   type     => $type,
- *   plugin_instance => $instance,
- *   type_instance   => $type_instance
- * }
+ * Submit the values to a single write function.
  */
-static int pplugin_dispatch_notification (pTHX_ HV *notif)
+static int pplugin_write (pTHX_ const char *plugin, AV *data_set, HV *values)
 {
-	notification_t n;
+	data_set_t   ds;
+	value_list_t vl = VALUE_LIST_INIT;
 
-	SV **tmp = NULL;
+	int ret;
 
-	if (NULL == notif)
+	if (NULL == values)
 		return -1;
 
-	memset (&n, 0, sizeof (n));
+	if (0 != hv2value_list (aTHX_ values, &vl))
+		return -1;
 
-	if (NULL != (tmp = hv_fetch (notif, "severity", 8, 0)))
-		n.severity = SvIV (*tmp);
-	else
-		n.severity = NOTIF_FAILURE;
+	if ((NULL != data_set)
+			&& (0 != av2data_set (aTHX_ data_set, vl.type, &ds)))
+		return -1;
 
-	if (NULL != (tmp = hv_fetch (notif, "time", 4, 0)))
-		n.time = (time_t)SvIV (*tmp);
-	else
-		n.time = time (NULL);
+	ret = plugin_write (plugin, NULL == data_set ? NULL : &ds, &vl);
+	if (0 != ret)
+		log_warn ("Dispatching value to plugin \"%s\" failed with status %i.",
+				NULL == plugin ? "<any>" : plugin, ret);
+
+	if (NULL != data_set)
+		sfree (ds.ds);
+	sfree (vl.values);
+	return ret;
+} /* static int pplugin_write (const char *plugin, HV *, HV *) */
 
-	if (NULL != (tmp = hv_fetch (notif, "message", 7, 0)))
-		sstrncpy (n.message, SvPV_nolen (*tmp), sizeof (n.message));
+/*
+ * Dispatch a notification.
+ */
+static int pplugin_dispatch_notification (pTHX_ HV *notif)
+{
+	notification_t n;
 
-	if (NULL != (tmp = hv_fetch (notif, "host", 4, 0)))
-		sstrncpy (n.host, SvPV_nolen (*tmp), sizeof (n.host));
-	else
-		sstrncpy (n.host, hostname_g, sizeof (n.host));
+	int ret;
 
-	if (NULL != (tmp = hv_fetch (notif, "plugin", 6, 0)))
-		sstrncpy (n.plugin, SvPV_nolen (*tmp), sizeof (n.plugin));
+	if (NULL == notif)
+		return -1;
 
-	if (NULL != (tmp = hv_fetch (notif, "plugin_instance", 15, 0)))
-		sstrncpy (n.plugin_instance, SvPV_nolen (*tmp),
-				sizeof (n.plugin_instance));
+	memset (&n, 0, sizeof (n));
 
-	if (NULL != (tmp = hv_fetch (notif, "type", 4, 0)))
-		sstrncpy (n.type, SvPV_nolen (*tmp), sizeof (n.type));
+	if (0 != hv2notification (aTHX_ notif, &n))
+		return -1;
 
-	if (NULL != (tmp = hv_fetch (notif, "type_instance", 13, 0)))
-		sstrncpy (n.type_instance, SvPV_nolen (*tmp), sizeof (n.type_instance));
-	return plugin_dispatch_notification (&n);
+	ret = plugin_dispatch_notification (&n);
+	plugin_notification_meta_free (n.meta);
+	return ret;
 } /* static int pplugin_dispatch_notification (HV *) */
 
 /*
@@ -803,14 +1049,14 @@ static int pplugin_call_all (pTHX_ int type, ...)
 		if (-1 == data_set2av (aTHX_ ds, pds)) {
 			av_clear (pds);
 			av_undef (pds);
-			pds = Nullav;
+			pds = (AV *)&PL_sv_undef;
 			ret = -1;
 		}
 
 		if (-1 == value_list2hv (aTHX_ vl, ds, pvl)) {
 			hv_clear (pvl);
 			hv_undef (pvl);
-			pvl = Nullhv;
+			pvl = (HV *)&PL_sv_undef;
 			ret = -1;
 		}
 
@@ -849,7 +1095,7 @@ static int pplugin_call_all (pTHX_ int type, ...)
 		if (-1 == notification2hv (aTHX_ n, notif)) {
 			hv_clear (notif);
 			hv_undef (notif);
-			notif = Nullhv;
+			notif = (HV *)&PL_sv_undef;
 			ret = -1;
 		}
 
@@ -884,92 +1130,491 @@ static int pplugin_call_all (pTHX_ int type, ...)
 } /* static int pplugin_call_all (int, ...) */
 
 /*
- * Exported Perl API.
- */
-
-/*
- * Collectd::plugin_register_data_set (type, dataset).
- *
- * type:
- *   type of the dataset
+ * collectd's perl interpreter based thread implementation.
  *
- * dataset:
- *   dataset to be registered
+ * This has been inspired by Perl's ithreads introduced in version 5.6.0.
  */
-static XS (Collectd_plugin_register_ds)
+
+/* must be called with perl_threads->mutex locked */
+static void c_ithread_destroy (c_ithread_t *ithread)
 {
-	SV  *data = NULL;
-	int ret   = 0;
+	dTHXa (ithread->interp);
 
-	dXSARGS;
+	assert (NULL != perl_threads);
 
-	if (2 != items) {
-		log_err ("Usage: Collectd::plugin_register_data_set(type, dataset)");
-		XSRETURN_EMPTY;
-	}
+	PERL_SET_CONTEXT (aTHX);
+	log_debug ("Shutting down Perl interpreter %p...", aTHX);
 
-	log_debug ("Collectd::plugin_register_data_set: "
-			"type = \"%s\", dataset = \"%s\"",
-			SvPV_nolen (ST (0)), SvPV_nolen (ST (1)));
+#if COLLECT_DEBUG
+	sv_report_used ();
 
-	data = ST (1);
+	--perl_threads->number_of_threads;
+#endif /* COLLECT_DEBUG */
 
-	if (SvROK (data) && (SVt_PVAV == SvTYPE (SvRV (data)))) {
-		ret = pplugin_register_data_set (aTHX_ SvPV_nolen (ST (0)),
-				(AV *)SvRV (data));
-	}
-	else {
-		log_err ("Collectd::plugin_register_data_set: Invalid data.");
-		XSRETURN_EMPTY;
-	}
+	perl_destruct (aTHX);
+	perl_free (aTHX);
 
-	if (0 == ret)
-		XSRETURN_YES;
+	if (NULL == ithread->prev)
+		perl_threads->head = ithread->next;
 	else
-		XSRETURN_EMPTY;
-} /* static XS (Collectd_plugin_register_ds) */
+		ithread->prev->next = ithread->next;
 
-/*
- * Collectd::plugin_unregister_data_set (type).
- *
- * type:
- *   type of the dataset
- */
-static XS (Collectd_plugin_unregister_ds)
-{
-	dXSARGS;
+	if (NULL == ithread->next)
+		perl_threads->tail = ithread->prev;
+	else
+		ithread->next->prev = ithread->prev;
 
-	if (1 != items) {
-		log_err ("Usage: Collectd::plugin_unregister_data_set(type)");
-		XSRETURN_EMPTY;
-	}
+	sfree (ithread);
+	return;
+} /* static void c_ithread_destroy (c_ithread_t *) */
 
-	log_debug ("Collectd::plugin_unregister_data_set: type = \"%s\"",
-			SvPV_nolen (ST (0)));
+static void c_ithread_destructor (void *arg)
+{
+	c_ithread_t *ithread = (c_ithread_t *)arg;
+	c_ithread_t *t = NULL;
 
-	if (0 == pplugin_unregister_data_set (SvPV_nolen (ST (0))))
-		XSRETURN_YES;
-	else
-		XSRETURN_EMPTY;
-} /* static XS (Collectd_plugin_register_ds) */
+	if (NULL == perl_threads)
+		return;
 
-/*
- * Collectd::plugin_dispatch_values (name, values).
- *
- * name:
- *   name of the plugin
- *
- * values:
- *   value list to submit
- */
-static XS (Collectd_plugin_dispatch_values)
-{
-	SV *values     = NULL;
-	int values_idx = 0;
+	pthread_mutex_lock (&perl_threads->mutex);
 
-	int ret = 0;
+	for (t = perl_threads->head; NULL != t; t = t->next)
+		if (t == ithread)
+			break;
 
-	dXSARGS;
+	/* the ithread no longer exists */
+	if (NULL == t)
+		return;
+
+	c_ithread_destroy (ithread);
+
+	pthread_mutex_unlock (&perl_threads->mutex);
+	return;
+} /* static void c_ithread_destructor (void *) */
+
+/* must be called with perl_threads->mutex locked */
+static c_ithread_t *c_ithread_create (PerlInterpreter *base)
+{
+	c_ithread_t *t = NULL;
+	dTHXa (NULL);
+
+	assert (NULL != perl_threads);
+
+	t = (c_ithread_t *)smalloc (sizeof (c_ithread_t));
+	memset (t, 0, sizeof (c_ithread_t));
+
+	t->interp = (NULL == base)
+		? NULL
+		: perl_clone (base, CLONEf_KEEP_PTR_TABLE);
+
+	aTHX = t->interp;
+
+	if ((NULL != base) && (NULL != PL_endav)) {
+		av_clear (PL_endav);
+		av_undef (PL_endav);
+		PL_endav = Nullav;
+	}
+
+#if COLLECT_DEBUG
+	++perl_threads->number_of_threads;
+#endif /* COLLECT_DEBUG */
+
+	t->next = NULL;
+
+	if (NULL == perl_threads->tail) {
+		perl_threads->head = t;
+		t->prev = NULL;
+	}
+	else {
+		perl_threads->tail->next = t;
+		t->prev = perl_threads->tail;
+	}
+
+	perl_threads->tail = t;
+
+	pthread_setspecific (perl_thr_key, (const void *)t);
+	return t;
+} /* static c_ithread_t *c_ithread_create (PerlInterpreter *) */
+
+/*
+ * Filter chains implementation.
+ */
+
+static int fc_call (pTHX_ int type, int cb_type, pfc_user_data_t *data, ...)
+{
+	int retvals = 0;
+
+	va_list ap;
+	int ret = 0;
+
+	notification_meta_t **meta  = NULL;
+	AV                   *pmeta = NULL;
+
+	dSP;
+
+	if ((type < 0) || (type >= FC_TYPES))
+		return -1;
+
+	if ((cb_type < 0) || (cb_type >= FC_CB_TYPES))
+		return -1;
+
+	va_start (ap, data);
+
+	ENTER;
+	SAVETMPS;
+
+	PUSHMARK (SP);
+
+	XPUSHs (sv_2mortal (newSViv ((IV)type)));
+	XPUSHs (sv_2mortal (newSVpv (data->name, 0)));
+	XPUSHs (sv_2mortal (newSViv ((IV)cb_type)));
+
+	if (FC_CB_CREATE == cb_type) {
+		/*
+		 * $_[0] = $ci;
+		 * $_[1] = $user_data;
+		 */
+		oconfig_item_t *ci;
+		HV *config = newHV ();
+
+		ci = va_arg (ap, oconfig_item_t *);
+
+		if (0 != oconfig_item2hv (aTHX_ ci, config)) {
+			hv_clear (config);
+			hv_undef (config);
+			config = (HV *)&PL_sv_undef;
+			ret = -1;
+		}
+
+		XPUSHs (sv_2mortal (newRV_noinc ((SV *)config)));
+	}
+	else if (FC_CB_DESTROY == cb_type) {
+		/*
+		 * $_[1] = $user_data;
+		 */
+
+		/* nothing to be done - the user data pointer
+		 * is pushed onto the stack later */
+	}
+	else if (FC_CB_EXEC == cb_type) {
+		/*
+		 * $_[0] = $ds;
+		 * $_[1] = $vl;
+		 * $_[2] = $meta;
+		 * $_[3] = $user_data;
+		 */
+		data_set_t   *ds;
+		value_list_t *vl;
+
+		AV *pds = newAV ();
+		HV *pvl = newHV ();
+
+		ds   = va_arg (ap, data_set_t *);
+		vl   = va_arg (ap, value_list_t *);
+		meta = va_arg (ap, notification_meta_t **);
+
+		if (0 != data_set2av (aTHX_ ds, pds)) {
+			av_clear (pds);
+			av_undef (pds);
+			pds = (AV *)&PL_sv_undef;
+			ret = -1;
+		}
+
+		if (0 != value_list2hv (aTHX_ vl, ds, pvl)) {
+			hv_clear (pvl);
+			hv_undef (pvl);
+			pvl = (HV *)&PL_sv_undef;
+			ret = -1;
+		}
+
+		if (NULL != meta) {
+			pmeta = newAV ();
+
+			if (0 != notification_meta2av (aTHX_ *meta, pmeta)) {
+				av_clear (pmeta);
+				av_undef (pmeta);
+				pmeta = (AV *)&PL_sv_undef;
+				ret = -1;
+			}
+		}
+		else {
+			pmeta = (AV *)&PL_sv_undef;
+		}
+
+		XPUSHs (sv_2mortal (newRV_noinc ((SV *)pds)));
+		XPUSHs (sv_2mortal (newRV_noinc ((SV *)pvl)));
+		XPUSHs (sv_2mortal (newRV_noinc ((SV *)pmeta)));
+	}
+
+	XPUSHs (sv_2mortal (newRV_inc (data->user_data)));
+
+	PUTBACK;
+
+	retvals = call_pv ("Collectd::fc_call", G_SCALAR);
+
+	if ((FC_CB_EXEC == cb_type) && (meta != NULL)) {
+		assert (pmeta != NULL);
+
+		plugin_notification_meta_free (*meta);
+		av2notification_meta (aTHX_ pmeta, meta);
+	}
+
+	SPAGAIN;
+	if (0 < retvals) {
+		SV *tmp = POPs;
+
+		/* the exec callbacks return a status, while
+		 * the others return a boolean value */
+		if (FC_CB_EXEC == cb_type)
+			ret = SvIV (tmp);
+		else if (! SvTRUE (tmp))
+			ret = -1;
+	}
+
+	PUTBACK;
+	FREETMPS;
+	LEAVE;
+
+	va_end (ap);
+	return ret;
+} /* static int fc_call (int, int, pfc_user_data_t *, ...) */
+
+static int fc_create (int type, const oconfig_item_t *ci, void **user_data)
+{
+	pfc_user_data_t *data;
+
+	int ret = 0;
+
+	dTHX;
+
+	if (NULL == perl_threads)
+		return 0;
+
+	if (NULL == aTHX) {
+		c_ithread_t *t = NULL;
+
+		pthread_mutex_lock (&perl_threads->mutex);
+		t = c_ithread_create (perl_threads->head->interp);
+		pthread_mutex_unlock (&perl_threads->mutex);
+
+		aTHX = t->interp;
+	}
+
+	log_debug ("fc_create: c_ithread: interp = %p (active threads: %i)",
+			aTHX, perl_threads->number_of_threads);
+
+	if ((1 != ci->values_num)
+			|| (OCONFIG_TYPE_STRING != ci->values[0].type)) {
+		log_warn ("A \"%s\" block expects a single string argument.",
+				(FC_MATCH == type) ? "Match" : "Target");
+		return -1;
+	}
+
+	data = (pfc_user_data_t *)smalloc (sizeof (*data));
+	data->name      = sstrdup (ci->values[0].value.string);
+	data->user_data = newSV (0);
+
+	ret = fc_call (aTHX_ type, FC_CB_CREATE, data, ci);
+
+	if (0 != ret)
+		PFC_USER_DATA_FREE (data);
+	else
+		*user_data = data;
+	return ret;
+} /* static int fc_create (int, const oconfig_item_t *, void **) */
+
+static int fc_destroy (int type, void **user_data)
+{
+	pfc_user_data_t *data = *(pfc_user_data_t **)user_data;
+
+	int ret = 0;
+
+	dTHX;
+
+	if ((NULL == perl_threads) || (NULL == data))
+		return 0;
+
+	if (NULL == aTHX) {
+		c_ithread_t *t = NULL;
+
+		pthread_mutex_lock (&perl_threads->mutex);
+		t = c_ithread_create (perl_threads->head->interp);
+		pthread_mutex_unlock (&perl_threads->mutex);
+
+		aTHX = t->interp;
+	}
+
+	log_debug ("fc_destroy: c_ithread: interp = %p (active threads: %i)",
+			aTHX, perl_threads->number_of_threads);
+
+	ret = fc_call (aTHX_ type, FC_CB_DESTROY, data);
+
+	PFC_USER_DATA_FREE (data);
+	*user_data = NULL;
+	return ret;
+} /* static int fc_destroy (int, void **) */
+
+static int fc_exec (int type, const data_set_t *ds, const value_list_t *vl,
+		notification_meta_t **meta, void **user_data)
+{
+	pfc_user_data_t *data = *(pfc_user_data_t **)user_data;
+
+	dTHX;
+
+	if (NULL == perl_threads)
+		return 0;
+
+	assert (NULL != data);
+
+	if (NULL == aTHX) {
+		c_ithread_t *t = NULL;
+
+		pthread_mutex_lock (&perl_threads->mutex);
+		t = c_ithread_create (perl_threads->head->interp);
+		pthread_mutex_unlock (&perl_threads->mutex);
+
+		aTHX = t->interp;
+	}
+
+	log_debug ("fc_exec: c_ithread: interp = %p (active threads: %i)",
+			aTHX, perl_threads->number_of_threads);
+
+	return fc_call (aTHX_ type, FC_CB_EXEC, data, ds, vl, meta);
+} /* static int fc_exec (int, const data_set_t *, const value_list_t *,
+		notification_meta_t **, void **) */
+
+static int pmatch_create (const oconfig_item_t *ci, void **user_data)
+{
+	return fc_create (FC_MATCH, ci, user_data);
+} /* static int pmatch_create (const oconfig_item_t *, void **) */
+
+static int pmatch_destroy (void **user_data)
+{
+	return fc_destroy (FC_MATCH, user_data);
+} /* static int pmatch_destroy (void **) */
+
+static int pmatch_match (const data_set_t *ds, const value_list_t *vl,
+		notification_meta_t **meta, void **user_data)
+{
+	return fc_exec (FC_MATCH, ds, vl, meta, user_data);
+} /* static int pmatch_match (const data_set_t *, const value_list_t *,
+		notification_meta_t **, void **) */
+
+static match_proc_t pmatch = {
+	pmatch_create, pmatch_destroy, pmatch_match
+};
+
+static int ptarget_create (const oconfig_item_t *ci, void **user_data)
+{
+	return fc_create (FC_TARGET, ci, user_data);
+} /* static int ptarget_create (const oconfig_item_t *, void **) */
+
+static int ptarget_destroy (void **user_data)
+{
+	return fc_destroy (FC_TARGET, user_data);
+} /* static int ptarget_destroy (void **) */
+
+static int ptarget_invoke (const data_set_t *ds, value_list_t *vl,
+		notification_meta_t **meta, void **user_data)
+{
+	return fc_exec (FC_TARGET, ds, vl, meta, user_data);
+} /* static int ptarget_invoke (const data_set_t *, value_list_t *,
+		notification_meta_t **, void **) */
+
+static target_proc_t ptarget = {
+	ptarget_create, ptarget_destroy, ptarget_invoke
+};
+
+/*
+ * Exported Perl API.
+ */
+
+/*
+ * Collectd::plugin_register_data_set (type, dataset).
+ *
+ * type:
+ *   type of the dataset
+ *
+ * dataset:
+ *   dataset to be registered
+ */
+static XS (Collectd_plugin_register_ds)
+{
+	SV  *data = NULL;
+	int ret   = 0;
+
+	dXSARGS;
+
+	log_warn ("Using plugin_register() to register new data-sets is "
+			"deprecated - add new entries to a custom types.db instead.");
+
+	if (2 != items) {
+		log_err ("Usage: Collectd::plugin_register_data_set(type, dataset)");
+		XSRETURN_EMPTY;
+	}
+
+	log_debug ("Collectd::plugin_register_data_set: "
+			"type = \"%s\", dataset = \"%s\"",
+			SvPV_nolen (ST (0)), SvPV_nolen (ST (1)));
+
+	data = ST (1);
+
+	if (SvROK (data) && (SVt_PVAV == SvTYPE (SvRV (data)))) {
+		ret = pplugin_register_data_set (aTHX_ SvPV_nolen (ST (0)),
+				(AV *)SvRV (data));
+	}
+	else {
+		log_err ("Collectd::plugin_register_data_set: Invalid data.");
+		XSRETURN_EMPTY;
+	}
+
+	if (0 == ret)
+		XSRETURN_YES;
+	else
+		XSRETURN_EMPTY;
+} /* static XS (Collectd_plugin_register_ds) */
+
+/*
+ * Collectd::plugin_unregister_data_set (type).
+ *
+ * type:
+ *   type of the dataset
+ */
+static XS (Collectd_plugin_unregister_ds)
+{
+	dXSARGS;
+
+	if (1 != items) {
+		log_err ("Usage: Collectd::plugin_unregister_data_set(type)");
+		XSRETURN_EMPTY;
+	}
+
+	log_debug ("Collectd::plugin_unregister_data_set: type = \"%s\"",
+			SvPV_nolen (ST (0)));
+
+	if (0 == pplugin_unregister_data_set (SvPV_nolen (ST (0))))
+		XSRETURN_YES;
+	else
+		XSRETURN_EMPTY;
+} /* static XS (Collectd_plugin_register_ds) */
+
+/*
+ * Collectd::plugin_dispatch_values (name, values).
+ *
+ * name:
+ *   name of the plugin
+ *
+ * values:
+ *   value list to submit
+ */
+static XS (Collectd_plugin_dispatch_values)
+{
+	SV *values     = NULL;
+	int values_idx = 0;
+
+	int ret = 0;
+
+	dXSARGS;
 
 	if (2 == items) {
 		log_warn ("Collectd::plugin_dispatch_values with two arguments "
@@ -1008,6 +1653,65 @@ static XS (Collectd_plugin_dispatch_values)
 		XSRETURN_EMPTY;
 } /* static XS (Collectd_plugin_dispatch_values) */
 
+/* Collectd::plugin_write (plugin, ds, vl).
+ *
+ * plugin:
+ *   name of the plugin to call, may be 'undef'
+ *
+ * ds:
+ *   data-set that describes the submitted values, may be 'undef'
+ *
+ * vl:
+ *   value-list to be written
+ */
+static XS (Collectd__plugin_write)
+{
+	char *plugin;
+	SV   *ds, *vl;
+	AV   *ds_array;
+
+	int ret;
+
+	dXSARGS;
+
+	if (3 != items) {
+		log_err ("Usage: Collectd::plugin_write(plugin, ds, vl)");
+		XSRETURN_EMPTY;
+	}
+
+	log_debug ("Collectd::plugin_write: plugin=\"%s\", ds=\"%s\", vl=\"%s\"",
+			SvPV_nolen (ST (0)), SvOK (ST (1)) ? SvPV_nolen (ST (1)) : "",
+			SvPV_nolen (ST (2)));
+
+	if (! SvOK (ST (0)))
+		plugin = NULL;
+	else
+		plugin = SvPV_nolen (ST (0));
+
+	ds = ST (1);
+	if (SvROK (ds) && (SVt_PVAV == SvTYPE (SvRV (ds))))
+		ds_array = (AV *)SvRV (ds);
+	else if (! SvOK (ds))
+		ds_array = NULL;
+	else {
+		log_err ("Collectd::plugin_write: Invalid data-set.");
+		XSRETURN_EMPTY;
+	}
+
+	vl = ST (2);
+	if (! (SvROK (vl) && (SVt_PVHV == SvTYPE (SvRV (vl))))) {
+		log_err ("Collectd::plugin_write: Invalid value-list.");
+		XSRETURN_EMPTY;
+	}
+
+	ret = pplugin_write (aTHX_ plugin, ds_array, (HV *)SvRV (vl));
+
+	if (0 == ret)
+		XSRETURN_YES;
+	else
+		XSRETURN_EMPTY;
+} /* static XS (Collectd__plugin_write) */
+
 /*
  * Collectd::_plugin_flush (plugin, timeout, identifier).
  *
@@ -1111,6 +1815,43 @@ static XS (Collectd_plugin_log)
 } /* static XS (Collectd_plugin_log) */
 
 /*
+ * Collectd::_fc_register (type, name)
+ *
+ * type:
+ *   match | target
+ *
+ * name:
+ *   name of the match
+ */
+static XS (Collectd__fc_register)
+{
+	int   type;
+	char *name;
+
+	int ret = 0;
+
+	dXSARGS;
+
+	if (2 != items) {
+		log_err ("Usage: Collectd::_fc_register(type, name)");
+		XSRETURN_EMPTY;
+	}
+
+	type = SvIV (ST (0));
+	name = SvPV_nolen (ST (1));
+
+	if (FC_MATCH == type)
+		ret = fc_register_match (name, pmatch);
+	else if (FC_TARGET == type)
+		ret = fc_register_target (name, ptarget);
+
+	if (0 == ret)
+		XSRETURN_YES;
+	else
+		XSRETURN_EMPTY;
+} /* static XS (Collectd_fc_register) */
+
+/*
  * Collectd::call_by_name (...).
  *
  * Call a Perl sub identified by its name passed through $Collectd::cb_name.
@@ -1140,118 +1881,12 @@ static XS (Collectd_call_by_name)
 } /* static XS (Collectd_call_by_name) */
 
 /*
- * collectd's perl interpreter based thread implementation.
- *
- * This has been inspired by Perl's ithreads introduced in version 5.6.0.
- */
-
-/* must be called with perl_threads->mutex locked */
-static void c_ithread_destroy (c_ithread_t *ithread)
-{
-	dTHXa (ithread->interp);
-
-	assert (NULL != perl_threads);
-
-	PERL_SET_CONTEXT (aTHX);
-	log_debug ("Shutting down Perl interpreter %p...", aTHX);
-
-#if COLLECT_DEBUG
-	sv_report_used ();
-
-	--perl_threads->number_of_threads;
-#endif /* COLLECT_DEBUG */
-
-	perl_destruct (aTHX);
-	perl_free (aTHX);
-
-	if (NULL == ithread->prev)
-		perl_threads->head = ithread->next;
-	else
-		ithread->prev->next = ithread->next;
-
-	if (NULL == ithread->next)
-		perl_threads->tail = ithread->prev;
-	else
-		ithread->next->prev = ithread->prev;
-
-	sfree (ithread);
-	return;
-} /* static void c_ithread_destroy (c_ithread_t *) */
-
-static void c_ithread_destructor (void *arg)
-{
-	c_ithread_t *ithread = (c_ithread_t *)arg;
-	c_ithread_t *t = NULL;
-
-	if (NULL == perl_threads)
-		return;
-
-	pthread_mutex_lock (&perl_threads->mutex);
-
-	for (t = perl_threads->head; NULL != t; t = t->next)
-		if (t == ithread)
-			break;
-
-	/* the ithread no longer exists */
-	if (NULL == t)
-		return;
-
-	c_ithread_destroy (ithread);
-
-	pthread_mutex_unlock (&perl_threads->mutex);
-	return;
-} /* static void c_ithread_destructor (void *) */
-
-/* must be called with perl_threads->mutex locked */
-static c_ithread_t *c_ithread_create (PerlInterpreter *base)
-{
-	c_ithread_t *t = NULL;
-	dTHXa (NULL);
-
-	assert (NULL != perl_threads);
-
-	t = (c_ithread_t *)smalloc (sizeof (c_ithread_t));
-	memset (t, 0, sizeof (c_ithread_t));
-
-	t->interp = (NULL == base)
-		? NULL
-		: perl_clone (base, CLONEf_KEEP_PTR_TABLE);
-
-	aTHX = t->interp;
-
-	if ((NULL != base) && (NULL != PL_endav)) {
-		av_clear (PL_endav);
-		av_undef (PL_endav);
-		PL_endav = Nullav;
-	}
-
-#if COLLECT_DEBUG
-	++perl_threads->number_of_threads;
-#endif /* COLLECT_DEBUG */
-
-	t->next = NULL;
-
-	if (NULL == perl_threads->tail) {
-		perl_threads->head = t;
-		t->prev = NULL;
-	}
-	else {
-		perl_threads->tail->next = t;
-		t->prev = perl_threads->tail;
-	}
-
-	perl_threads->tail = t;
-
-	pthread_setspecific (perl_thr_key, (const void *)t);
-	return t;
-} /* static c_ithread_t *c_ithread_create (PerlInterpreter *) */
-
-/*
  * Interface to collectd.
  */
 
 static int perl_init (void)
 {
+	int status;
 	dTHX;
 
 	if (NULL == perl_threads)
@@ -1269,7 +1904,19 @@ static int perl_init (void)
 
 	log_debug ("perl_init: c_ithread: interp = %p (active threads: %i)",
 			aTHX, perl_threads->number_of_threads);
-	return pplugin_call_all (aTHX_ PLUGIN_INIT);
+
+	/* Lock the base thread to avoid race conditions with c_ithread_create().
+	 * See https://github.com/collectd/collectd/issues/9 and
+	 *     https://github.com/collectd/collectd/issues/1706 for details. */
+
+	assert (aTHX == perl_threads->head->interp);
+	pthread_mutex_lock (&perl_threads->mutex);
+
+	status = pplugin_call_all (aTHX_ PLUGIN_INIT);
+
+	pthread_mutex_unlock (&perl_threads->mutex);
+
+	return status;
 } /* static int perl_init (void) */
 
 static int perl_read (void)
@@ -1289,13 +1936,20 @@ static int perl_read (void)
 		aTHX = t->interp;
 	}
 
+	/* Assert that we're not running as the base thread. Otherwise, we might
+	 * run into concurrency issues with c_ithread_create(). See
+	 * https://github.com/collectd/collectd/issues/9 for details. */
+	assert (aTHX != perl_threads->head->interp);
+
 	log_debug ("perl_read: c_ithread: interp = %p (active threads: %i)",
 			aTHX, perl_threads->number_of_threads);
 	return pplugin_call_all (aTHX_ PLUGIN_READ);
 } /* static int perl_read (void) */
 
-static int perl_write (const data_set_t *ds, const value_list_t *vl)
+static int perl_write (const data_set_t *ds, const value_list_t *vl,
+		user_data_t __attribute__((unused)) *user_data)
 {
+	int status;
 	dTHX;
 
 	if (NULL == perl_threads)
@@ -1311,12 +1965,24 @@ static int perl_write (const data_set_t *ds, const value_list_t *vl)
 		aTHX = t->interp;
 	}
 
+	/* Lock the base thread if this is not called from one of the read threads
+	 * to avoid race conditions with c_ithread_create(). See
+	 * https://github.com/collectd/collectd/issues/9 for details. */
+	if (aTHX == perl_threads->head->interp)
+		pthread_mutex_lock (&perl_threads->mutex);
+
 	log_debug ("perl_write: c_ithread: interp = %p (active threads: %i)",
 			aTHX, perl_threads->number_of_threads);
-	return pplugin_call_all (aTHX_ PLUGIN_WRITE, ds, vl);
+	status = pplugin_call_all (aTHX_ PLUGIN_WRITE, ds, vl);
+
+	if (aTHX == perl_threads->head->interp)
+		pthread_mutex_unlock (&perl_threads->mutex);
+
+	return status;
 } /* static int perl_write (const data_set_t *, const value_list_t *) */
 
-static void perl_log (int level, const char *msg)
+static void perl_log (int level, const char *msg,
+		user_data_t __attribute__((unused)) *user_data)
 {
 	dTHX;
 
@@ -1333,11 +1999,22 @@ static void perl_log (int level, const char *msg)
 		aTHX = t->interp;
 	}
 
+	/* Lock the base thread if this is not called from one of the read threads
+	 * to avoid race conditions with c_ithread_create(). See
+	 * https://github.com/collectd/collectd/issues/9 for details. */
+	if (aTHX == perl_threads->head->interp)
+		pthread_mutex_lock (&perl_threads->mutex);
+
 	pplugin_call_all (aTHX_ PLUGIN_LOG, level, msg);
+
+	if (aTHX == perl_threads->head->interp)
+		pthread_mutex_unlock (&perl_threads->mutex);
+
 	return;
 } /* static void perl_log (int, const char *) */
 
-static int perl_notify (const notification_t *notif)
+static int perl_notify (const notification_t *notif,
+		user_data_t __attribute__((unused)) *user_data)
 {
 	dTHX;
 
@@ -1356,7 +2033,8 @@ static int perl_notify (const notification_t *notif)
 	return pplugin_call_all (aTHX_ PLUGIN_NOTIF, notif);
 } /* static int perl_notify (const notification_t *) */
 
-static int perl_flush (int timeout, const char *identifier)
+static int perl_flush (int timeout, const char *identifier,
+		user_data_t __attribute__((unused)) *user_data)
 {
 	dTHX;
 
@@ -1471,8 +2149,18 @@ static int g_iv_set (pTHX_ SV *var, MAGIC *mg)
 	return 0;
 } /* static int g_iv_set (pTHX_ SV *, MAGIC *) */
 
-static MGVTBL g_pv_vtbl = { g_pv_get, g_pv_set, NULL, NULL, NULL, NULL, NULL };
-static MGVTBL g_iv_vtbl = { g_iv_get, g_iv_set, NULL, NULL, NULL, NULL, NULL };
+static MGVTBL g_pv_vtbl = {
+	g_pv_get, g_pv_set, NULL, NULL, NULL, NULL, NULL
+#if HAVE_PERL_STRUCT_MGVTBL_SVT_LOCAL
+		, NULL
+#endif
+};
+static MGVTBL g_iv_vtbl = {
+	g_iv_get, g_iv_set, NULL, NULL, NULL, NULL, NULL
+#if HAVE_PERL_STRUCT_MGVTBL_SVT_LOCAL
+		, NULL
+#endif
+};
 
 /* bootstrap the Collectd module */
 static void xs_init (pTHX)
@@ -1592,14 +2280,15 @@ static int init_pi (int argc, char **argv)
 
 	perl_run (aTHX);
 
-	plugin_register_log ("perl", perl_log);
-	plugin_register_notification ("perl", perl_notify);
+	plugin_register_log ("perl", perl_log, /* user_data = */ NULL);
+	plugin_register_notification ("perl", perl_notify,
+			/* user_data = */ NULL);
 	plugin_register_init ("perl", perl_init);
 
 	plugin_register_read ("perl", perl_read);
 
-	plugin_register_write ("perl", perl_write);
-	plugin_register_flush ("perl", perl_flush);
+	plugin_register_write ("perl", perl_write, /* user_data = */ NULL);
+	plugin_register_flush ("perl", perl_flush, /* user_data = */ NULL);
 	plugin_register_shutdown ("perl", perl_shutdown);
 	return 0;
 } /* static int init_pi (const char **, const int) */
@@ -1765,7 +2454,7 @@ static int perl_config_plugin (pTHX_ oconfig_item_t *ci)
 		hv_undef (config);
 
 		log_err ("Unable to convert configuration to a Perl hash value.");
-		config = Nullhv;
+		config = (HV *)&PL_sv_undef;
 	}
 
 	ENTER;