X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=src%2Fperl.c;h=dc548b2590269328376cf6341b6d0b4ddc2891c8;hb=acbd25344a59c091b087311804d375b759077e32;hp=1ed9d003d12ad84d3ce105fd18bdca70f8c6931d;hpb=939a113b288dfdee7df2263c682d27d7146c6013;p=collectd.git

diff --git a/src/perl.c b/src/perl.c
index 1ed9d003..dc548b25 100644
--- a/src/perl.c
+++ b/src/perl.c
@@ -24,6 +24,9 @@
  * interface for collectd plugins written in perl.
  */
 
+/* do not automatically get the thread specific perl interpreter */
+#define PERL_NO_GET_CONTEXT
+
 #include "collectd.h"
 
 #include "configfile.h"
@@ -42,6 +45,16 @@
 #include "plugin.h"
 #include "common.h"
 
+#include <pthread.h>
+
+#if !defined(USE_ITHREADS)
+# error "Perl does not support ithreads!"
+#endif /* !defined(USE_ITHREADS) */
+
+/* clear the Perl sub's stack frame
+ * (this should only be used inside an XSUB) */
+#define CLEAR_STACK_FRAME PL_stack_sp = PL_stack_base + *PL_markstack_ptr
+
 #define PLUGIN_INIT     0
 #define PLUGIN_READ     1
 #define PLUGIN_WRITE    2
@@ -64,14 +77,45 @@ static XS (Collectd_plugin_register_ds);
 static XS (Collectd_plugin_unregister_ds);
 static XS (Collectd_plugin_dispatch_values);
 static XS (Collectd_plugin_log);
+static XS (Collectd_call_by_name);
+
+/*
+ * private data types
+ */
+
+typedef struct c_ithread_s {
+	/* the thread's Perl interpreter */
+	PerlInterpreter *interp;
+
+	/* double linked list of threads */
+	struct c_ithread_s *prev;
+	struct c_ithread_s *next;
+} c_ithread_t;
+
+typedef struct {
+	c_ithread_t *head;
+	c_ithread_t *tail;
+
+#if COLLECT_DEBUG
+	/* some usage stats */
+	int number_of_threads;
+#endif /* COLLECT_DEBUG */
+
+	pthread_mutex_t mutex;
+} c_ithread_list_t;
 
 /*
  * private variables
  */
 
-static PerlInterpreter *perl = NULL;
+/* if perl_threads != NULL perl_threads->head must
+ * point to the "base" thread */
+static c_ithread_list_t *perl_threads = NULL;
 
-static int  perl_argc   = 0;
+/* the key used to store each pthread's ithread */
+static pthread_key_t perl_thr_key;
+
+static int    perl_argc = 0;
 static char **perl_argv = NULL;
 
 static char base_name[DATA_MAX_NAME_LEN] = "";
@@ -85,6 +129,7 @@ static struct {
 	{ "Collectd::plugin_unregister_data_set", Collectd_plugin_unregister_ds },
 	{ "Collectd::plugin_dispatch_values",     Collectd_plugin_dispatch_values },
 	{ "Collectd::plugin_log",                 Collectd_plugin_log },
+	{ "Collectd::call_by_name",               Collectd_call_by_name },
 	{ "", NULL }
 };
 
@@ -109,6 +154,24 @@ struct {
 	{ "", 0 }
 };
 
+struct {
+	char  name[64];
+	char *var;
+} g_strings[] =
+{
+	{ "Collectd::hostname_g", hostname_g },
+	{ "", NULL }
+};
+
+struct {
+	char  name[64];
+	int  *var;
+} g_integers[] =
+{
+	{ "Collectd::interval_g", &interval_g },
+	{ "", NULL }
+};
+
 /*
  * Helper functions for data type conversion.
  */
@@ -125,14 +188,14 @@ struct {
  *   ...
  * ]
  */
-static int hv2data_source (HV *hash, data_source_t *ds)
+static int hv2data_source (pTHX_ HV *hash, data_source_t *ds)
 {
 	SV **tmp = NULL;
 
 	if ((NULL == hash) || (NULL == ds))
 		return -1;
 
-	if (NULL != (tmp = Perl_hv_fetch (perl, hash, "name", 4, 0))) {
+	if (NULL != (tmp = hv_fetch (hash, "name", 4, 0))) {
 		strncpy (ds->name, SvPV_nolen (*tmp), DATA_MAX_NAME_LEN);
 		ds->name[DATA_MAX_NAME_LEN - 1] = '\0';
 	}
@@ -141,7 +204,7 @@ static int hv2data_source (HV *hash, data_source_t *ds)
 		return -1;
 	}
 
-	if (NULL != (tmp = Perl_hv_fetch (perl, hash, "type", 4, 0))) {
+	if (NULL != (tmp = hv_fetch (hash, "type", 4, 0))) {
 		ds->type = SvIV (*tmp);
 
 		if ((DS_TYPE_COUNTER != ds->type) && (DS_TYPE_GAUGE != ds->type)) {
@@ -153,19 +216,19 @@ static int hv2data_source (HV *hash, data_source_t *ds)
 		ds->type = DS_TYPE_COUNTER;
 	}
 
-	if (NULL != (tmp = Perl_hv_fetch (perl, hash, "min", 3, 0)))
+	if (NULL != (tmp = hv_fetch (hash, "min", 3, 0)))
 		ds->min = SvNV (*tmp);
 	else
 		ds->min = NAN;
 
-	if (NULL != (tmp = Perl_hv_fetch (perl, hash, "max", 3, 0)))
+	if (NULL != (tmp = hv_fetch (hash, "max", 3, 0)))
 		ds->max = SvNV (*tmp);
 	else
 		ds->max = NAN;
 	return 0;
 } /* static data_source_t *hv2data_source (HV *) */
 
-static int av2value (char *name, AV *array, value_t *value, int len)
+static int av2value (pTHX_ char *name, AV *array, value_t *value, int len)
 {
 	const data_set_t *ds;
 
@@ -174,8 +237,8 @@ static int av2value (char *name, AV *array, value_t *value, int len)
 	if ((NULL == name) || (NULL == array) || (NULL == value))
 		return -1;
 
-	if (Perl_av_len (perl, array) < len - 1)
-		len = Perl_av_len (perl, array) + 1;
+	if (av_len (array) < len - 1)
+		len = av_len (array) + 1;
 
 	if (0 >= len)
 		return -1;
@@ -192,7 +255,7 @@ static int av2value (char *name, AV *array, value_t *value, int len)
 	}
 
 	for (i = 0; i < len; ++i) {
-		SV **tmp = Perl_av_fetch (perl, array, i, 0);
+		SV **tmp = av_fetch (array, i, 0);
 
 		if (NULL != tmp) {
 			if (DS_TYPE_COUNTER == ds->ds[i].type)
@@ -207,44 +270,42 @@ static int av2value (char *name, AV *array, value_t *value, int len)
 	return len;
 } /* static int av2value (char *, AV *, value_t *, int) */
 
-static int data_set2av (data_set_t *ds, AV *array)
+static int data_set2av (pTHX_ data_set_t *ds, AV *array)
 {
 	int i = 0;
 
 	if ((NULL == ds) || (NULL == array))
 		return -1;
 
-	Perl_av_extend (perl, array, ds->ds_num);
+	av_extend (array, ds->ds_num);
 
 	for (i = 0; i < ds->ds_num; ++i) {
-		HV *source = Perl_newHV (perl);
+		HV *source = newHV ();
 
-		if (NULL == Perl_hv_store (perl, source, "name", 4,
-				Perl_newSVpv (perl, ds->ds[i].name, 0), 0))
+		if (NULL == hv_store (source, "name", 4,
+				newSVpv (ds->ds[i].name, 0), 0))
 			return -1;
 
-		if (NULL == Perl_hv_store (perl, source, "type", 4,
-				Perl_newSViv (perl, ds->ds[i].type), 0))
+		if (NULL == hv_store (source, "type", 4, newSViv (ds->ds[i].type), 0))
 			return -1;
 
 		if (! isnan (ds->ds[i].min))
-			if (NULL == Perl_hv_store (perl, source, "min", 3,
-					Perl_newSVnv (perl, ds->ds[i].min), 0))
+			if (NULL == hv_store (source, "min", 3,
+					newSVnv (ds->ds[i].min), 0))
 				return -1;
 
 		if (! isnan (ds->ds[i].max))
-			if (NULL == Perl_hv_store (perl, source, "max", 3,
-					Perl_newSVnv (perl, ds->ds[i].max), 0))
+			if (NULL == hv_store (source, "max", 3,
+					newSVnv (ds->ds[i].max), 0))
 				return -1;
 
-		if (NULL == Perl_av_store (perl, array, i,
-				Perl_newRV_noinc (perl, (SV *)source)))
+		if (NULL == av_store (array, i, newRV_noinc ((SV *)source)))
 			return -1;
 	}
 	return 0;
 } /* static int data_set2av (data_set_t *, AV *) */
 
-static int value_list2hv (value_list_t *vl, data_set_t *ds, HV *hash)
+static int value_list2hv (pTHX_ value_list_t *vl, data_set_t *ds, HV *hash)
 {
 	AV *values = NULL;
 
@@ -261,50 +322,46 @@ static int value_list2hv (value_list_t *vl, data_set_t *ds, HV *hash)
 		len = ds->ds_num;
 	}
 
-	values = Perl_newAV (perl);
-	Perl_av_extend (perl, values, len - 1);
+	values = newAV ();
+	av_extend (values, len - 1);
 
 	for (i = 0; i < len; ++i) {
 		SV *val = NULL;
 
 		if (DS_TYPE_COUNTER == ds->ds[i].type)
-			val = Perl_newSViv (perl, vl->values[i].counter);
+			val = newSViv (vl->values[i].counter);
 		else
-			val = Perl_newSVnv (perl, vl->values[i].gauge);
+			val = newSVnv (vl->values[i].gauge);
 
-		if (NULL == Perl_av_store (perl, values, i, val)) {
-			Perl_av_undef (perl, values);
+		if (NULL == av_store (values, i, val)) {
+			av_undef (values);
 			return -1;
 		}
 	}
 
-	if (NULL == Perl_hv_store (perl, hash, "values", 6,
-			Perl_newRV_noinc (perl, (SV *)values), 0))
+	if (NULL == hv_store (hash, "values", 6, newRV_noinc ((SV *)values), 0))
 		return -1;
 
 	if (0 != vl->time)
-		if (NULL == Perl_hv_store (perl, hash, "time", 4,
-				Perl_newSViv (perl, vl->time), 0))
+		if (NULL == hv_store (hash, "time", 4, newSViv (vl->time), 0))
 			return -1;
 
 	if ('\0' != vl->host[0])
-		if (NULL == Perl_hv_store (perl, hash, "host", 4,
-				Perl_newSVpv (perl, vl->host, 0), 0))
+		if (NULL == hv_store (hash, "host", 4, newSVpv (vl->host, 0), 0))
 			return -1;
 
 	if ('\0' != vl->plugin[0])
-		if (NULL == Perl_hv_store (perl, hash, "plugin", 6,
-				Perl_newSVpv (perl, vl->plugin, 0), 0))
+		if (NULL == hv_store (hash, "plugin", 6, newSVpv (vl->plugin, 0), 0))
 			return -1;
 
 	if ('\0' != vl->plugin_instance[0])
-		if (NULL == Perl_hv_store (perl, hash, "plugin_instance", 15,
-				Perl_newSVpv (perl, vl->plugin_instance, 0), 0))
+		if (NULL == hv_store (hash, "plugin_instance", 15,
+				newSVpv (vl->plugin_instance, 0), 0))
 			return -1;
 
 	if ('\0' != vl->type_instance[0])
-		if (NULL == Perl_hv_store (perl, hash, "type_instance", 13,
-				Perl_newSVpv (perl, vl->type_instance, 0), 0))
+		if (NULL == hv_store (hash, "type_instance", 13,
+				newSVpv (vl->type_instance, 0), 0))
 			return -1;
 	return 0;
 } /* static int value2av (value_list_t *, data_set_t *, HV *) */
@@ -328,9 +385,10 @@ static char *get_module_name (char *buf, size_t buf_len, const char *module) {
 /*
  * Add a plugin's data set definition.
  */
-static int pplugin_register_data_set (char *name, AV *dataset)
+static int pplugin_register_data_set (pTHX_ char *name, AV *dataset)
 {
 	int len = -1;
+	int ret = 0;
 	int i   = 0;
 
 	data_source_t *ds  = NULL;
@@ -339,7 +397,7 @@ static int pplugin_register_data_set (char *name, AV *dataset)
 	if ((NULL == name) || (NULL == dataset))
 		return -1;
 
-	len = Perl_av_len (perl, dataset);
+	len = av_len (dataset);
 
 	if (-1 == len)
 		return -1;
@@ -348,7 +406,7 @@ static int pplugin_register_data_set (char *name, AV *dataset)
 	set = (data_set_t *)smalloc (sizeof (data_set_t));
 
 	for (i = 0; i <= len; ++i) {
-		SV **elem = Perl_av_fetch (perl, dataset, i, 0);
+		SV **elem = av_fetch (dataset, i, 0);
 
 		if (NULL == elem)
 			return -1;
@@ -358,7 +416,7 @@ static int pplugin_register_data_set (char *name, AV *dataset)
 			return -1;
 		}
 
-		if (-1 == hv2data_source ((HV *)SvRV (*elem), &ds[i]))
+		if (-1 == hv2data_source (aTHX_ (HV *)SvRV (*elem), &ds[i]))
 			return -1;
 
 		log_debug ("pplugin_register_data_set: "
@@ -371,7 +429,12 @@ static int pplugin_register_data_set (char *name, AV *dataset)
 
 	set->ds_num = len + 1;
 	set->ds = ds;
-	return plugin_register_data_set (set);
+
+	ret = plugin_register_data_set (set);
+
+	free (ds);
+	free (set);
+	return ret;
 } /* static int pplugin_register_data_set (char *, SV *) */
 
 /*
@@ -397,7 +460,7 @@ static int pplugin_unregister_data_set (char *name)
  *   type_instance   => $tinstance,
  * }
  */
-static int pplugin_dispatch_values (char *name, HV *values)
+static int pplugin_dispatch_values (pTHX_ char *name, HV *values)
 {
 	value_list_t list = VALUE_LIST_INIT;
 	value_t      *val = NULL;
@@ -409,7 +472,7 @@ static int pplugin_dispatch_values (char *name, HV *values)
 	if ((NULL == name) || (NULL == values))
 		return -1;
 
-	if ((NULL == (tmp = Perl_hv_fetch (perl, values, "values", 6, 0)))
+	if ((NULL == (tmp = hv_fetch (values, "values", 6, 0)))
 			|| (! (SvROK (*tmp) && (SVt_PVAV == SvTYPE (SvRV (*tmp)))))) {
 		log_err ("pplugin_dispatch_values: No valid values given.");
 		return -1;
@@ -417,14 +480,14 @@ static int pplugin_dispatch_values (char *name, HV *values)
 
 	{
 		AV  *array = (AV *)SvRV (*tmp);
-		int len    = Perl_av_len (perl, array) + 1;
+		int len    = av_len (array) + 1;
 
 		if (len <= 0)
 			return -1;
 
 		val = (value_t *)smalloc (len * sizeof (value_t));
 
-		list.values_len = av2value (name, (AV *)SvRV (*tmp), val, len);
+		list.values_len = av2value (aTHX_ name, (AV *)SvRV (*tmp), val, len);
 		list.values = val;
 
 		if (-1 == list.values_len) {
@@ -433,14 +496,14 @@ static int pplugin_dispatch_values (char *name, HV *values)
 		}
 	}
 
-	if (NULL != (tmp = Perl_hv_fetch (perl, values, "time", 4, 0))) {
+	if (NULL != (tmp = hv_fetch (values, "time", 4, 0))) {
 		list.time = (time_t)SvIV (*tmp);
 	}
 	else {
 		list.time = time (NULL);
 	}
 
-	if (NULL != (tmp = Perl_hv_fetch (perl, values, "host", 4, 0))) {
+	if (NULL != (tmp = hv_fetch (values, "host", 4, 0))) {
 		strncpy (list.host, SvPV_nolen (*tmp), DATA_MAX_NAME_LEN);
 		list.host[DATA_MAX_NAME_LEN - 1] = '\0';
 	}
@@ -448,18 +511,18 @@ static int pplugin_dispatch_values (char *name, HV *values)
 		strcpy (list.host, hostname_g);
 	}
 
-	if (NULL != (tmp = Perl_hv_fetch (perl, values, "plugin", 6, 0))) {
+	if (NULL != (tmp = hv_fetch (values, "plugin", 6, 0))) {
 		strncpy (list.plugin, SvPV_nolen (*tmp), DATA_MAX_NAME_LEN);
 		list.plugin[DATA_MAX_NAME_LEN - 1] = '\0';
 	}
 
-	if (NULL != (tmp = Perl_hv_fetch (perl, values,
+	if (NULL != (tmp = hv_fetch (values,
 			"plugin_instance", 15, 0))) {
 		strncpy (list.plugin_instance, SvPV_nolen (*tmp), DATA_MAX_NAME_LEN);
 		list.plugin_instance[DATA_MAX_NAME_LEN - 1] = '\0';
 	}
 
-	if (NULL != (tmp = Perl_hv_fetch (perl, values, "type_instance", 13, 0))) {
+	if (NULL != (tmp = hv_fetch (values, "type_instance", 13, 0))) {
 		strncpy (list.type_instance, SvPV_nolen (*tmp), DATA_MAX_NAME_LEN);
 		list.type_instance[DATA_MAX_NAME_LEN - 1] = '\0';
 	}
@@ -473,7 +536,7 @@ static int pplugin_dispatch_values (char *name, HV *values)
 /*
  * Call all working functions of the given type.
  */
-static int pplugin_call_all (int type, ...)
+static int pplugin_call_all (pTHX_ int type, ...)
 {
 	int retvals = 0;
 
@@ -492,7 +555,7 @@ static int pplugin_call_all (int type, ...)
 
 	PUSHMARK (SP);
 
-	XPUSHs (sv_2mortal (Perl_newSViv (perl, (IV)type)));
+	XPUSHs (sv_2mortal (newSViv ((IV)type)));
 
 	if (PLUGIN_WRITE == type) {
 		/*
@@ -522,21 +585,21 @@ static int pplugin_call_all (int type, ...)
 		data_set_t   *ds;
 		value_list_t *vl;
 
-		AV *pds = Perl_newAV (perl);
-		HV *pvl = Perl_newHV (perl);
+		AV *pds = newAV ();
+		HV *pvl = newHV ();
 
 		ds = va_arg (ap, data_set_t *);
 		vl = va_arg (ap, value_list_t *);
 
-		if (-1 == data_set2av (ds, pds))
+		if (-1 == data_set2av (aTHX_ ds, pds))
 			return -1;
 
-		if (-1 == value_list2hv (vl, ds, pvl))
+		if (-1 == value_list2hv (aTHX_ vl, ds, pvl))
 			return -1;
 
-		XPUSHs (sv_2mortal (Perl_newSVpv (perl, ds->type, 0)));
-		XPUSHs (sv_2mortal (Perl_newRV_noinc (perl, (SV *)pds)));
-		XPUSHs (sv_2mortal (Perl_newRV_noinc (perl, (SV *)pvl)));
+		XPUSHs (sv_2mortal (newSVpv (ds->type, 0)));
+		XPUSHs (sv_2mortal (newRV_noinc ((SV *)pds)));
+		XPUSHs (sv_2mortal (newRV_noinc ((SV *)pvl)));
 	}
 	else if (PLUGIN_LOG == type) {
 		/*
@@ -544,13 +607,13 @@ static int pplugin_call_all (int type, ...)
 		 *
 		 * $_[1] = $message;
 		 */
-		XPUSHs (sv_2mortal (Perl_newSViv (perl, va_arg (ap, int))));
-		XPUSHs (sv_2mortal (Perl_newSVpv (perl, va_arg (ap, char *), 0)));
+		XPUSHs (sv_2mortal (newSViv (va_arg (ap, int))));
+		XPUSHs (sv_2mortal (newSVpv (va_arg (ap, char *), 0)));
 	}
 
 	PUTBACK;
 
-	retvals = Perl_call_pv (perl, "Collectd::plugin_call_all", G_SCALAR);
+	retvals = call_pv ("Collectd::plugin_call_all", G_SCALAR);
 
 	SPAGAIN;
 	if (0 < retvals) {
@@ -599,7 +662,7 @@ static XS (Collectd_plugin_register_ds)
 	data = ST (1);
 
 	if (SvROK (data) && (SVt_PVAV == SvTYPE (SvRV (data)))) {
-		ret = pplugin_register_data_set (SvPV_nolen (ST (0)),
+		ret = pplugin_register_data_set (aTHX_ SvPV_nolen (ST (0)),
 				(AV *)SvRV (data));
 	}
 	else {
@@ -673,7 +736,8 @@ static XS (Collectd_plugin_dispatch_values)
 	if ((NULL == ST (0)) || (NULL == values))
 		XSRETURN_EMPTY;
 
-	ret = pplugin_dispatch_values (SvPV_nolen (ST (0)), (HV *)SvRV (values));
+	ret = pplugin_dispatch_values (aTHX_ SvPV_nolen (ST (0)),
+			(HV *)SvRV (values));
 
 	if (0 == ret)
 		XSRETURN_YES;
@@ -703,71 +767,285 @@ static XS (Collectd_plugin_log)
 	XSRETURN_YES;
 } /* static XS (Collectd_plugin_log) */
 
+/*
+ * Collectd::call_by_name (...).
+ *
+ * Call a Perl sub identified by its name passed through $Collectd::cb_name.
+ */
+static XS (Collectd_call_by_name)
+{
+	SV   *tmp  = NULL;
+	char *name = NULL;
+
+	if (NULL == (tmp = get_sv ("Collectd::cb_name", 0))) {
+		sv_setpv (get_sv ("@", 1), "cb_name has not been set");
+		CLEAR_STACK_FRAME;
+		return;
+	}
+
+	name = SvPV_nolen (tmp);
+
+	if (NULL == get_cv (name, 0)) {
+		sv_setpvf (get_sv ("@", 1), "unknown callback \"%s\"", name);
+		CLEAR_STACK_FRAME;
+		return;
+	}
+
+	/* simply pass on the subroutine call without touching the stack,
+	 * thus leaving any arguments and return values in place */
+	call_pv (name, 0);
+} /* 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) {
+		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)
 {
-	if (NULL == perl)
+	dTHX;
+
+	if (NULL == perl_threads)
 		return 0;
 
-	PERL_SET_CONTEXT (perl);
-	return pplugin_call_all (PLUGIN_INIT);
+	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 ("perl_init: c_ithread: interp = %p (active threads: %i)",
+			aTHX, perl_threads->number_of_threads);
+	return pplugin_call_all (aTHX_ PLUGIN_INIT);
 } /* static int perl_init (void) */
 
 static int perl_read (void)
 {
-	if (NULL == perl)
+	dTHX;
+
+	if (NULL == perl_threads)
 		return 0;
 
-	PERL_SET_CONTEXT (perl);
-	return pplugin_call_all (PLUGIN_READ);
+	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 ("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)
 {
-	if (NULL == perl)
+	dTHX;
+
+	if (NULL == perl_threads)
 		return 0;
 
-	PERL_SET_CONTEXT (perl);
-	return pplugin_call_all (PLUGIN_WRITE, ds, vl);
+	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 ("perl_write: c_ithread: interp = %p (active threads: %i)",
+			aTHX, perl_threads->number_of_threads);
+	return pplugin_call_all (aTHX_ PLUGIN_WRITE, ds, vl);
 } /* static int perl_write (const data_set_t *, const value_list_t *) */
 
 static void perl_log (int level, const char *msg)
 {
-	if (NULL == perl)
+	dTHX;
+
+	if (NULL == perl_threads)
 		return;
 
-	PERL_SET_CONTEXT (perl);
-	pplugin_call_all (PLUGIN_LOG, level, msg);
+	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;
+	}
+
+	pplugin_call_all (aTHX_ PLUGIN_LOG, level, msg);
 	return;
 } /* static void perl_log (int, const char *) */
 
 static int perl_shutdown (void)
 {
+	c_ithread_t *t = NULL;
+
 	int ret = 0;
 
+	dTHX;
+
 	plugin_unregister_complex_config ("perl");
 
-	if (NULL == perl)
+	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 ("perl_shutdown: c_ithread: interp = %p (active threads: %i)",
+			aTHX, perl_threads->number_of_threads);
+
 	plugin_unregister_log ("perl");
 	plugin_unregister_init ("perl");
 	plugin_unregister_read ("perl");
 	plugin_unregister_write ("perl");
 
-	PERL_SET_CONTEXT (perl);
-	ret = pplugin_call_all (PLUGIN_SHUTDOWN);
+	ret = pplugin_call_all (aTHX_ PLUGIN_SHUTDOWN);
 
-#if COLLECT_DEBUG
-	Perl_sv_report_used (perl);
-#endif /* COLLECT_DEBUG */
+	pthread_mutex_lock (&perl_threads->mutex);
+	t = perl_threads->tail;
+
+	while (NULL != t) {
+		c_ithread_t *thr = t;
 
-	perl_destruct (perl);
-	perl_free (perl);
-	perl = NULL;
+		/* the pointer has to be advanced before destroying
+		 * the thread as this will free the memory */
+		t = t->prev;
+
+		c_ithread_destroy (thr);
+	}
+
+	pthread_mutex_unlock (&perl_threads->mutex);
+	pthread_mutex_destroy (&perl_threads->mutex);
+
+	sfree (perl_threads);
+
+	pthread_key_delete (perl_thr_key);
 
 	PERL_SYS_TERM ();
 
@@ -775,10 +1053,50 @@ static int perl_shutdown (void)
 	return ret;
 } /* static void perl_shutdown (void) */
 
+/*
+ * Access functions for global variables.
+ *
+ * These functions implement the "magic" used to access
+ * the global variables from Perl.
+ */
+
+static int g_pv_get (pTHX_ SV *var, MAGIC *mg)
+{
+	char *pv = mg->mg_ptr;
+	sv_setpv (var, pv);
+	return 0;
+} /* static int g_pv_get (pTHX_ SV *, MAGIC *) */
+
+static int g_pv_set (pTHX_ SV *var, MAGIC *mg)
+{
+	char *pv = mg->mg_ptr;
+	strncpy (pv, SvPV_nolen (var), DATA_MAX_NAME_LEN);
+	pv[DATA_MAX_NAME_LEN - 1] = '\0';
+	return 0;
+} /* static int g_pv_set (pTHX_ SV *, MAGIC *) */
+
+static int g_iv_get (pTHX_ SV *var, MAGIC *mg)
+{
+	int *iv = (int *)mg->mg_ptr;
+	sv_setiv (var, *iv);
+	return 0;
+} /* static int g_iv_get (pTHX_ SV *, MAGIC *) */
+
+static int g_iv_set (pTHX_ SV *var, MAGIC *mg)
+{
+	int *iv = (int *)mg->mg_ptr;
+	*iv = (int)SvIV (var);
+	return 0;
+} /* static int g_iv_set (pTHX_ SV *, MAGIC *) */
+
+static MGVTBL g_pv_vtbl = { g_pv_get, g_pv_set, NULL, NULL, NULL };
+static MGVTBL g_iv_vtbl = { g_iv_get, g_iv_set, NULL, NULL, NULL };
+
 /* bootstrap the Collectd module */
 static void xs_init (pTHX)
 {
 	HV   *stash = NULL;
+	SV   *tmp   = NULL;
 	char *file  = __FILE__;
 
 	int i = 0;
@@ -786,25 +1104,45 @@ static void xs_init (pTHX)
 	dXSUB_SYS;
 
 	/* enable usage of Perl modules using shared libraries */
-	Perl_newXS (perl, "DynaLoader::boot_DynaLoader", boot_DynaLoader, file);
+	newXS ("DynaLoader::boot_DynaLoader", boot_DynaLoader, file);
 
 	/* register API */
 	for (i = 0; NULL != api[i].f; ++i)
-		Perl_newXS (perl, api[i].name, api[i].f, file);
+		newXS (api[i].name, api[i].f, file);
 
-	stash = Perl_gv_stashpv (perl, "Collectd", 1);
+	stash = gv_stashpv ("Collectd", 1);
 
 	/* export "constants" */
 	for (i = 0; '\0' != constants[i].name[0]; ++i)
-		Perl_newCONSTSUB (perl, stash, constants[i].name,
-				Perl_newSViv (perl, constants[i].value));
+		newCONSTSUB (stash, constants[i].name, newSViv (constants[i].value));
+
+	/* export global variables
+	 * by adding "magic" to the SV's representing the globale variables
+	 * perl is able to automagically call the get/set function when
+	 * accessing any such variable (this is basically the same as using
+	 * tie() in Perl) */
+	/* global strings */
+	for (i = 0; '\0' != g_strings[i].name[0]; ++i) {
+		tmp = get_sv (g_strings[i].name, 1);
+		sv_magicext (tmp, NULL, PERL_MAGIC_ext, &g_pv_vtbl,
+				g_strings[i].var, 0);
+	}
+
+	/* global integers */
+	for (i = 0; '\0' != g_integers[i].name[0]; ++i) {
+		tmp = get_sv (g_integers[i].name, 1);
+		sv_magicext (tmp, NULL, PERL_MAGIC_ext, &g_iv_vtbl,
+				(char *)g_integers[i].var, 0);
+	}
 	return;
 } /* static void xs_init (pTHX) */
 
 /* Initialize the global Perl interpreter. */
 static int init_pi (int argc, char **argv)
 {
-	if (NULL != perl)
+	dTHXa (NULL);
+
+	if (NULL != perl_threads)
 		return 0;
 
 	log_info ("Initializing Perl interpreter...");
@@ -817,25 +1155,47 @@ static int init_pi (int argc, char **argv)
 	}
 #endif /* COLLECT_DEBUG */
 
+	if (0 != pthread_key_create (&perl_thr_key, c_ithread_destructor)) {
+		log_err ("init_pi: pthread_key_create failed");
+
+		/* this must not happen - cowardly giving up if it does */
+		exit (1);
+	}
+
 	PERL_SYS_INIT3 (&argc, &argv, &environ);
 
-	if (NULL == (perl = perl_alloc ())) {
-		log_err ("module_register: Not enough memory.");
+	perl_threads = (c_ithread_list_t *)smalloc (sizeof (c_ithread_list_t));
+	memset (perl_threads, 0, sizeof (c_ithread_list_t));
+
+	pthread_mutex_init (&perl_threads->mutex, NULL);
+	/* locking the mutex should not be necessary at this point
+	 * but let's just do it for the sake of completeness */
+	pthread_mutex_lock (&perl_threads->mutex);
+
+	perl_threads->head = c_ithread_create (NULL);
+	perl_threads->tail = perl_threads->head;
+
+	if (NULL == (perl_threads->head->interp = perl_alloc ())) {
+		log_err ("init_pi: Not enough memory.");
 		exit (3);
 	}
-	perl_construct (perl);
+
+	aTHX = perl_threads->head->interp;
+	pthread_mutex_unlock (&perl_threads->mutex);
+
+	perl_construct (aTHX);
 
 	PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
 
-	if (0 != perl_parse (perl, xs_init, argc, argv, NULL)) {
-		log_err ("module_register: Unable to bootstrap Collectd.");
+	if (0 != perl_parse (aTHX_ xs_init, argc, argv, NULL)) {
+		log_err ("init_pi: Unable to bootstrap Collectd.");
 		exit (1);
 	}
 
 	/* Set $0 to "collectd" because perl_parse() has to set it to "-e". */
-	Perl_sv_setpv (perl, Perl_get_sv (perl, "0", 0), "collectd");
+	sv_setpv (get_sv ("0", 0), "collectd");
 
-	perl_run (perl);
+	perl_run (aTHX);
 
 	plugin_register_log ("perl", perl_log);
 	plugin_register_init ("perl", perl_init);
@@ -850,15 +1210,17 @@ static int init_pi (int argc, char **argv)
 /*
  * LoadPlugin "<Plugin>"
  */
-static int perl_config_loadplugin (oconfig_item_t *ci)
+static int perl_config_loadplugin (pTHX_ oconfig_item_t *ci)
 {
 	char module_name[DATA_MAX_NAME_LEN];
 
 	char *value = NULL;
 
 	if ((0 != ci->children_num) || (1 != ci->values_num)
-			|| (OCONFIG_TYPE_STRING != ci->values[0].type))
+			|| (OCONFIG_TYPE_STRING != ci->values[0].type)) {
+		log_err ("LoadPlugin expects a single string argument.");
 		return 1;
+	}
 
 	value = ci->values[0].value.string;
 
@@ -868,24 +1230,29 @@ static int perl_config_loadplugin (oconfig_item_t *ci)
 	}
 
 	init_pi (perl_argc, perl_argv);
+	assert (NULL != perl_threads);
+	assert (NULL != perl_threads->head);
+
+	aTHX = perl_threads->head->interp;
 
 	log_debug ("perl_config: loading perl plugin \"%s\"", value);
-	Perl_load_module (perl, PERL_LOADMOD_NOIMPORT,
-			Perl_newSVpv (perl, module_name, strlen (module_name)),
-			Nullsv);
+	load_module (PERL_LOADMOD_NOIMPORT,
+			newSVpv (module_name, strlen (module_name)), Nullsv);
 	return 0;
 } /* static int perl_config_loadplugin (oconfig_item_it *) */
 
 /*
  * BaseName "<Name>"
  */
-static int perl_config_basename (oconfig_item_t *ci)
+static int perl_config_basename (pTHX_ oconfig_item_t *ci)
 {
 	char *value = NULL;
 
 	if ((0 != ci->children_num) || (1 != ci->values_num)
-			|| (OCONFIG_TYPE_STRING != ci->values[0].type))
+			|| (OCONFIG_TYPE_STRING != ci->values[0].type)) {
+		log_err ("BaseName expects a single string argument.");
 		return 1;
+	}
 
 	value = ci->values[0].value.string;
 
@@ -898,13 +1265,15 @@ static int perl_config_basename (oconfig_item_t *ci)
 /*
  * EnableDebugger "<Package>"|""
  */
-static int perl_config_enabledebugger (oconfig_item_t *ci)
+static int perl_config_enabledebugger (pTHX_ oconfig_item_t *ci)
 {
 	char *value = NULL;
 
 	if ((0 != ci->children_num) || (1 != ci->values_num)
-			|| (OCONFIG_TYPE_STRING != ci->values[0].type))
+			|| (OCONFIG_TYPE_STRING != ci->values[0].type)) {
+		log_err ("EnableDebugger expects a single string argument.");
 		return 1;
+	}
 
 	value = ci->values[0].value.string;
 
@@ -932,17 +1301,19 @@ static int perl_config_enabledebugger (oconfig_item_t *ci)
 /*
  * IncludeDir "<Dir>"
  */
-static int perl_config_includedir (oconfig_item_t *ci)
+static int perl_config_includedir (pTHX_ oconfig_item_t *ci)
 {
 	char *value = NULL;
 
 	if ((0 != ci->children_num) || (1 != ci->values_num)
-			|| (OCONFIG_TYPE_STRING != ci->values[0].type))
+			|| (OCONFIG_TYPE_STRING != ci->values[0].type)) {
+		log_err ("IncludeDir expects a single string argument.");
 		return 1;
+	}
 
 	value = ci->values[0].value.string;
 
-	if (NULL == perl) {
+	if (NULL == aTHX) {
 		perl_argv = (char **)realloc (perl_argv,
 				(++perl_argc + 1) * sizeof (char *));
 
@@ -959,9 +1330,8 @@ static int perl_config_includedir (oconfig_item_t *ci)
 	}
 	else {
 		/* prepend the directory to @INC */
-		Perl_av_unshift (perl, GvAVn (PL_incgv), 1);
-		Perl_av_store (perl, GvAVn (PL_incgv),
-				0, Perl_newSVpv (perl, value, strlen (value)));
+		av_unshift (GvAVn (PL_incgv), 1);
+		av_store (GvAVn (PL_incgv), 0, newSVpv (value, strlen (value)));
 	}
 	return 0;
 } /* static int perl_config_includedir (oconfig_item_it *) */
@@ -970,17 +1340,24 @@ static int perl_config (oconfig_item_t *ci)
 {
 	int i = 0;
 
+	dTHX;
+
+	/* dTHX does not get any valid values in case Perl
+	 * has not been initialized */
+	if (NULL == perl_threads)
+		aTHX = NULL;
+
 	for (i = 0; i < ci->children_num; ++i) {
 		oconfig_item_t *c = ci->children + i;
 
 		if (0 == strcasecmp (c->key, "LoadPlugin"))
-			perl_config_loadplugin (c);
+			perl_config_loadplugin (aTHX_ c);
 		else if (0 == strcasecmp (c->key, "BaseName"))
-			perl_config_basename (c);
+			perl_config_basename (aTHX_ c);
 		else if (0 == strcasecmp (c->key, "EnableDebugger"))
-			perl_config_enabledebugger (c);
+			perl_config_enabledebugger (aTHX_ c);
 		else if (0 == strcasecmp (c->key, "IncludeDir"))
-			perl_config_includedir (c);
+			perl_config_includedir (aTHX_ c);
 		else
 			log_warn ("Ignoring unknown config key \"%s\".", c->key);
 	}