Merge branch 'nspoll'

10 files changed, 638 insertions, 3 deletions

diff --git a/runtime/Makefile.am b/runtime/Makefile.am
index 7896e71d..9047c83d 100644
--- a/runtime/Makefile.am
+++ b/runtime/Makefile.am
@@ -137,7 +137,10 @@ lmnet_la_LDFLAGS = -module -avoid-version
 lmnet_la_LIBADD =
 
 # network stream master class and stream factory
-lmnetstrms_la_SOURCES = netstrms.c netstrms.h netstrm.c netstrm.h nssel.c nssel.h
+lmnetstrms_la_SOURCES = netstrms.c netstrms.h \
+			netstrm.c netstrm.h \
+			nssel.c nssel.h \
+			nspoll.c nspoll.h
 lmnetstrms_la_CPPFLAGS = $(PTHREADS_CFLAGS) $(RSRT_CFLAGS)
 lmnetstrms_la_LDFLAGS = -module -avoid-version
 lmnetstrms_la_LIBADD =
@@ -153,7 +156,9 @@ lmstrmsrv_la_LIBADD =
 
 # plain tcp driver - main driver
 pkglib_LTLIBRARIES += lmnsd_ptcp.la
-lmnsd_ptcp_la_SOURCES = nsd_ptcp.c nsd_ptcp.h nsdsel_ptcp.c nsdsel_ptcp.h
+lmnsd_ptcp_la_SOURCES = nsd_ptcp.c nsd_ptcp.h \
+		  	nsdsel_ptcp.c nsdsel_ptcp.h \
+			nsdpoll_ptcp.c nsdpoll_ptcp.h
 lmnsd_ptcp_la_CPPFLAGS = $(PTHREADS_CFLAGS) $(RSRT_CFLAGS)
 lmnsd_ptcp_la_LDFLAGS = -module -avoid-version
 lmnsd_ptcp_la_LIBADD =
diff --git a/runtime/netstrms.c b/runtime/netstrms.c
index 6b28e7ea..e9ff2568 100644
--- a/runtime/netstrms.c
+++ b/runtime/netstrms.c
@@ -36,6 +36,7 @@
 #include "nsd.h"
 #include "netstrm.h"
 #include "nssel.h"
+#include "nspoll.h"
 #include "netstrms.h"
 
 MODULE_TYPE_LIB
@@ -304,6 +305,7 @@ ENDObjClassInit(netstrms)
 BEGINmodExit
 CODESTARTmodExit
 	nsselClassExit();
+	nspollClassExit();
 	netstrmsClassExit();
 	netstrmClassExit(); /* we use this object, so we must exit it after we are finished */
 ENDmodExit
@@ -322,6 +324,7 @@ CODESTARTmodInit
 	/* Initialize all classes that are in our module - this includes ourselfs */
 	CHKiRet(netstrmClassInit(pModInfo));
 	CHKiRet(nsselClassInit(pModInfo));
+	CHKiRet(nspollClassInit(pModInfo));
 	CHKiRet(netstrmsClassInit(pModInfo));
 ENDmodInit
 /* vi:set ai:
diff --git a/runtime/nsd.h b/runtime/nsd.h
index 8668c934..e5b9320b 100644
--- a/runtime/nsd.h
+++ b/runtime/nsd.h
@@ -87,4 +87,13 @@ BEGINinterface(nsdsel) /* name must also be changed in ENDinterface macro! */
 ENDinterface(nsdsel)
 #define nsdselCURR_IF_VERSION 1 /* increment whenever you change the interface structure! */
 
+/* interface  for the epoll call */
+BEGINinterface(nsdpoll) /* name must also be changed in ENDinterface macro! */
+	rsRetVal (*Construct)(nsdpoll_t **ppThis);
+	rsRetVal (*Destruct)(nsdpoll_t **ppThis);
+	rsRetVal (*Ctl)(nsdpoll_t *pNsdpoll, nsd_t *pNsd, int id, void *pUsr, int mode, int op);
+	rsRetVal (*Wait)(nsdpoll_t *pNsdpoll, int timeout, int *idRdy, void **ppUsr);
+ENDinterface(nsdpoll)
+#define nsdpollCURR_IF_VERSION 1 /* increment whenever you change the interface structure! */
+
 #endif /* #ifndef INCLUDED_NSD_H */
diff --git a/runtime/nsd_ptcp.c b/runtime/nsd_ptcp.c
index fe31ab40..96881097 100644
--- a/runtime/nsd_ptcp.c
+++ b/runtime/nsd_ptcp.c
@@ -562,6 +562,7 @@ finalize_it:
 static rsRetVal
 Rcv(nsd_t *pNsd, uchar *pRcvBuf, ssize_t *pLenBuf)
 {
+	char errStr[1024];
 	DEFiRet;
 	nsd_ptcp_t *pThis = (nsd_ptcp_t*) pNsd;
 	ISOBJ_TYPE_assert(pThis, nsd_ptcp);
@@ -571,7 +572,9 @@ Rcv(nsd_t *pNsd, uchar *pRcvBuf, ssize_t *pLenBuf)
 	if(*pLenBuf == 0) {
 		ABORT_FINALIZE(RS_RET_CLOSED);
 	} else if (*pLenBuf < 0) {
-		ABORT_FINALIZE(RS_RET_ERR);
+		rs_strerror_r(errno, errStr, sizeof(errStr));
+		dbgprintf("error during recv on NSD %p: %s\n", pNsd, errStr);
+		ABORT_FINALIZE(RS_RET_RCV_ERR);
 	}
 
 finalize_it:
@@ -821,6 +824,7 @@ ENDObjClassInit(nsd_ptcp)
 
 BEGINmodExit
 CODESTARTmodExit
+	nsdpoll_ptcpClassExit();
 	nsdsel_ptcpClassExit();
 	nsd_ptcpClassExit();
 ENDmodExit
@@ -839,6 +843,7 @@ CODESTARTmodInit
 	/* Initialize all classes that are in our module - this includes ourselfs */
 	CHKiRet(nsd_ptcpClassInit(pModInfo)); /* must be done after tcps_sess, as we use it */
 	CHKiRet(nsdsel_ptcpClassInit(pModInfo)); /* must be done after tcps_sess, as we use it */
+	CHKiRet(nsdpoll_ptcpClassInit(pModInfo)); /* must be done after tcps_sess, as we use it */
 ENDmodInit
 /* vi:set ai:
  */
diff --git a/runtime/nsdpoll_ptcp.c b/runtime/nsdpoll_ptcp.c
new file mode 100644
index 00000000..445ecc71
--- /dev/null
+++ b/runtime/nsdpoll_ptcp.c
@@ -0,0 +1,284 @@
+/* nsdpoll_ptcp.c
+ *
+ * An implementation of the nsd epoll() interface for plain tcp sockets.
+ * 
+ * Copyright 2009 Rainer Gerhards and Adiscon GmbH.
+ *
+ * This file is part of the rsyslog runtime library.
+ *
+ * The rsyslog runtime library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * The rsyslog runtime library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with the rsyslog runtime library.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * A copy of the GPL can be found in the file "COPYING" in this distribution.
+ * A copy of the LGPL can be found in the file "COPYING.LESSER" in this distribution.
+ */
+#include "config.h"
+
+#include <stdlib.h>
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+#if HAVE_SYS_EPOLL_H
+#	include <sys/epoll.h>
+#endif
+
+#include "rsyslog.h"
+#include "module-template.h"
+#include "obj.h"
+#include "errmsg.h"
+#include "srUtils.h"
+#include "nspoll.h"
+#include "nsd_ptcp.h"
+#include "nsdpoll_ptcp.h"
+#include "unlimited_select.h"
+
+/* static data */
+DEFobjStaticHelpers
+DEFobjCurrIf(errmsg)
+DEFobjCurrIf(glbl)
+
+
+/* -START------------------------- helpers for event list ------------------------------------ */
+
+/* add new entry to list. We assume that the fd is not already present and DO NOT check this!
+ * Returns newly created entry in pEvtLst.
+ * Note that we currently need to use level-triggered mode, because the upper layers do not work
+ * in parallel. As such, in edge-triggered mode we may not get notified, because new data comes
+ * in after we have read everything that was present. To use ET mode, we need to change the upper
+ * peers so that they immediately start a new wait before processing the data read. That obviously
+ * requires more elaborate redesign and we postpone this until the current more simplictic mode has
+ * been proven OK in practice.
+ * rgerhards, 2009-11-18
+ */
+static inline rsRetVal
+addEvent(nsdpoll_ptcp_t *pThis, int id, void *pUsr, int mode, nsd_ptcp_t *pSock, nsdpoll_epollevt_lst_t **pEvtLst) {
+	nsdpoll_epollevt_lst_t *pNew;
+	DEFiRet;
+
+	CHKmalloc(pNew = (nsdpoll_epollevt_lst_t*) malloc(sizeof(nsdpoll_epollevt_lst_t)));
+	pNew->id = id;
+	pNew->pUsr = pUsr;
+	pNew->pSock = pSock;
+	pNew->event.events = 0; /* TODO: at some time we should be able to use EPOLLET */
+	if(mode & NSDPOLL_IN)
+		pNew->event.events |= EPOLLIN;
+	if(mode & NSDPOLL_OUT)
+		pNew->event.events |= EPOLLOUT;
+	pNew->event.data.u64 = (uint64) pNew;
+	pNew->pNext = pThis->pRoot;
+	pThis->pRoot = pNew;
+	*pEvtLst = pNew;
+
+finalize_it:
+	RETiRet;
+}
+
+
+/* find and unlink the entry identified by id/pUsr from the list.
+ * rgerhards, 2009-11-23
+ */
+static inline rsRetVal
+unlinkEvent(nsdpoll_ptcp_t *pThis, int id, void *pUsr, nsdpoll_epollevt_lst_t **ppEvtLst) {
+	nsdpoll_epollevt_lst_t *pEvtLst;
+	nsdpoll_epollevt_lst_t *pPrev = NULL;
+	DEFiRet;
+
+	pEvtLst = pThis->pRoot;
+	while(pEvtLst != NULL && !(pEvtLst->id == id && pEvtLst->pUsr == pUsr)) {
+		pPrev = pEvtLst;
+		pEvtLst = pEvtLst->pNext;
+	}
+	if(pEvtLst == NULL)
+		ABORT_FINALIZE(RS_RET_NOT_FOUND);
+
+	*ppEvtLst = pEvtLst;
+
+	/* unlink */
+	if(pPrev == NULL)
+		pThis->pRoot = pEvtLst->pNext;
+	else
+		pPrev->pNext = pEvtLst->pNext;
+
+finalize_it:
+	RETiRet;
+}
+
+
+/* destruct the provided element. It must already be unlinked from the list.
+ * rgerhards, 2009-11-23
+ */
+static inline rsRetVal
+delEvent(nsdpoll_epollevt_lst_t **ppEvtLst) {
+	DEFiRet;
+	free(*ppEvtLst);
+	*ppEvtLst = NULL;
+	RETiRet;
+}
+
+
+/* -END--------------------------- helpers for event list ------------------------------------ */
+
+
+/* Standard-Constructor
+ */
+BEGINobjConstruct(nsdpoll_ptcp) /* be sure to specify the object type also in END macro! */
+#	if defined(EPOLL_CLOEXEC) && defined(HAVE_EPOLL_CREATE1)
+		DBGPRINTF("imudp uses epoll_create1()\n");
+		pThis->efd = epoll_create1(EPOLL_CLOEXEC);
+#	else
+		DBGPRINTF("imudp uses epoll_create()\n");
+		pThis->efd = epoll_create(NUM_EPOLL_EVENTS);
+#	endif
+	if(pThis->efd < 0) {
+		DBGPRINTF("epoll_create1() could not create fd\n");
+		ABORT_FINALIZE(RS_RET_IO_ERROR);
+	}
+finalize_it:
+ENDobjConstruct(nsdpoll_ptcp)
+
+
+/* destructor for the nsdpoll_ptcp object */
+BEGINobjDestruct(nsdpoll_ptcp) /* be sure to specify the object type also in END and CODESTART macros! */
+CODESTARTobjDestruct(nsdpoll_ptcp)
+ENDobjDestruct(nsdpoll_ptcp)
+
+
+/* Modify socket set */
+static rsRetVal
+Ctl(nsdpoll_t *pNsdpoll, nsd_t *pNsd, int id, void *pUsr, int mode, int op) {
+	nsdpoll_ptcp_t *pThis = (nsdpoll_ptcp_t*) pNsdpoll;
+	nsd_ptcp_t *pSock = (nsd_ptcp_t*) pNsd;
+	nsdpoll_epollevt_lst_t *pEventLst;
+	int errSave;
+	char errStr[512];
+	DEFiRet;
+
+	if(op == NSDPOLL_ADD) {
+		dbgprintf("adding nsdpoll entry %d/%p, sock %d\n", id, pUsr, pSock->sock);
+		CHKiRet(addEvent(pThis, id, pUsr, mode, pSock, &pEventLst));
+		if(epoll_ctl(pThis->efd, EPOLL_CTL_ADD,  pSock->sock, &pEventLst->event) < 0) {
+			errSave = errno;
+			rs_strerror_r(errSave, errStr, sizeof(errStr));
+			errmsg.LogError(errSave, RS_RET_ERR_EPOLL_CTL,
+				"epoll_ctl failed on fd %d, id %d/%p, op %d with %s\n",
+				pSock->sock, id, pUsr, mode, errStr);
+		}
+	} else if(op == NSDPOLL_DEL) {
+		dbgprintf("removing nsdpoll entry %d/%p, sock %d\n", id, pUsr, pSock->sock);
+		CHKiRet(unlinkEvent(pThis, id, pUsr, &pEventLst));
+		if(epoll_ctl(pThis->efd, EPOLL_CTL_DEL, pSock->sock, &pEventLst->event) < 0) {
+			errSave = errno;
+			rs_strerror_r(errSave, errStr, sizeof(errStr));
+			errmsg.LogError(errSave, RS_RET_ERR_EPOLL_CTL,
+				"epoll_ctl failed on fd %d, id %d/%p, op %d with %s\n",
+				pSock->sock, id, pUsr, mode, errStr);
+			ABORT_FINALIZE(RS_RET_ERR_EPOLL_CTL);
+		}
+		CHKiRet(delEvent(&pEventLst));
+	} else {
+		dbgprintf("program error: invalid NSDPOLL_mode %d - ignoring request\n", op);
+		ABORT_FINALIZE(RS_RET_ERR);
+	}
+
+finalize_it:
+	RETiRet;
+}
+
+
+/* Wait for io to become ready. After the successful call, idRdy contains the
+ * id set by the caller for that i/o event, ppUsr is a pointer to a location
+ * where the user pointer shall be stored.
+ * TODO: this is a trivial implementation that only polls one event at a time. We
+ *       may later extend it to poll for multiple events, what would cause less 
+ *       overhead.
+ * rgerhards, 2009-11-18
+ */
+static rsRetVal
+Wait(nsdpoll_t *pNsdpoll, int timeout, int *idRdy, void **ppUsr) {
+	nsdpoll_ptcp_t *pThis = (nsdpoll_ptcp_t*) pNsdpoll;
+	nsdpoll_epollevt_lst_t *pOurEvt;
+	struct epoll_event event;
+	int nfds;
+	DEFiRet;
+
+	assert(idRdy != NULL);
+	assert(ppUsr != NULL);
+
+	nfds = epoll_wait(pThis->efd, &event, 1, timeout);
+	if(nfds == -1) {
+		if(errno == EINTR) {
+			ABORT_FINALIZE(RS_RET_EINTR);
+		} else {
+			DBGPRINTF("epoll() returned with error code %d\n", errno);
+			ABORT_FINALIZE(RS_RET_ERR_EPOLL);
+		}
+	} else if(nfds == 0) {
+		ABORT_FINALIZE(RS_RET_TIMEOUT);
+	}
+
+	/* we got a valid event, so tell the caller... */
+	pOurEvt = (nsdpoll_epollevt_lst_t*) event.data.u64;
+	*idRdy = pOurEvt->id;
+	*ppUsr = pOurEvt->pUsr;
+
+finalize_it:
+	RETiRet;
+}
+
+
+/* ------------------------------ end support for the epoll() interface ------------------------------ */
+
+
+/* queryInterface function */
+BEGINobjQueryInterface(nsdpoll_ptcp)
+CODESTARTobjQueryInterface(nsdpoll_ptcp)
+	if(pIf->ifVersion != nsdCURR_IF_VERSION) {/* check for current version, increment on each change */
+		ABORT_FINALIZE(RS_RET_INTERFACE_NOT_SUPPORTED);
+	}
+
+	/* ok, we have the right interface, so let's fill it
+	 * Please note that we may also do some backwards-compatibility
+	 * work here (if we can support an older interface version - that,
+	 * of course, also affects the "if" above).
+	 */
+	pIf->Construct = (rsRetVal(*)(nsdpoll_t**)) nsdpoll_ptcpConstruct;
+	pIf->Destruct = (rsRetVal(*)(nsdpoll_t**)) nsdpoll_ptcpDestruct;
+	pIf->Ctl = Ctl;
+	pIf->Wait = Wait;
+finalize_it:
+ENDobjQueryInterface(nsdpoll_ptcp)
+
+
+/* exit our class
+ */
+BEGINObjClassExit(nsdpoll_ptcp, OBJ_IS_CORE_MODULE) /* CHANGE class also in END MACRO! */
+CODESTARTObjClassExit(nsdpoll_ptcp)
+	/* release objects we no longer need */
+	objRelease(glbl, CORE_COMPONENT);
+	objRelease(errmsg, CORE_COMPONENT);
+ENDObjClassExit(nsdpoll_ptcp)
+
+
+/* Initialize the nsdpoll_ptcp class. Must be called as the very first method
+ * before anything else is called inside this class.
+ * rgerhards, 2008-02-19
+ */
+BEGINObjClassInit(nsdpoll_ptcp, 1, OBJ_IS_CORE_MODULE) /* class, version */
+	/* request objects we use */
+	CHKiRet(objUse(errmsg, CORE_COMPONENT));
+	CHKiRet(objUse(glbl, CORE_COMPONENT));
+
+	/* set our own handlers */
+ENDObjClassInit(nsdpoll_ptcp)
+/* vi:set ai:
+ */
diff --git a/runtime/nsdpoll_ptcp.h b/runtime/nsdpoll_ptcp.h
new file mode 100644
index 00000000..ccdb87f0
--- /dev/null
+++ b/runtime/nsdpoll_ptcp.h
@@ -0,0 +1,55 @@
+/* An implementation of the nsd poll interface for plain tcp sockets.
+ *
+ * Copyright 2009 Rainer Gerhards and Adiscon GmbH.
+ *
+ * This file is part of the rsyslog runtime library.
+ *
+ * The rsyslog runtime library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * The rsyslog runtime library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with the rsyslog runtime library.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * A copy of the GPL can be found in the file "COPYING" in this distribution.
+ * A copy of the LGPL can be found in the file "COPYING.LESSER" in this distribution.
+ */
+
+#ifndef INCLUDED_NSDPOLL_PTCP_H
+#define INCLUDED_NSDPOLL_PTCP_H
+
+#include "nsd.h"
+typedef nsdpoll_if_t nsdpoll_ptcp_if_t; /* we just *implement* this interface */
+/* a helper object to keep track of the epoll event records
+ * Note that we need to keep track of that list because we need to
+ * free the events when they are no longer needed.
+ */
+typedef struct nsdpoll_epollevt_lst_s nsdpoll_epollevt_lst_t;
+struct nsdpoll_epollevt_lst_s {
+	epoll_event_t event;
+	int id;
+	void *pUsr;
+	nsd_ptcp_t *pSock;	/* our associated netstream driver data */
+	nsdpoll_epollevt_lst_t *pNext;
+};
+
+/* the nsdpoll_ptcp object */
+struct nsdpoll_ptcp_s {
+	BEGINobjInstance;	/* Data to implement generic object - MUST be the first data element! */
+	int efd;		/* file descriptor used by epoll */
+	nsdpoll_epollevt_lst_t *pRoot;	/* Root of the epoll event list */
+};
+
+/* interface is defined in nsd.h, we just implement it! */
+#define nsdpoll_ptcpCURR_IF_VERSION nsdCURR_IF_VERSION
+
+/* prototypes */
+PROTOTYPEObj(nsdpoll_ptcp);
+
+#endif /* #ifndef INCLUDED_NSDPOLL_PTCP_H */
diff --git a/runtime/nspoll.c b/runtime/nspoll.c
new file mode 100644
index 00000000..f287cd4e
--- /dev/null
+++ b/runtime/nspoll.c
@@ -0,0 +1,198 @@
+/* nspoll.c
+ *
+ * This is an io waiter interface utilizing the much-more-efficient poll/epoll API.
+ * Note that it may not always be available for a given driver. If so, that is reported
+ * back to the upper peer which then should consult a nssel-based io waiter.
+ * 
+ * Work on this module begun 2009-11-18 by Rainer Gerhards.
+ *
+ * Copyright 2009 Rainer Gerhards and Adiscon GmbH.
+ *
+ * This file is part of the rsyslog runtime library.
+ *
+ * The rsyslog runtime library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * The rsyslog runtime library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with the rsyslog runtime library.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * A copy of the GPL can be found in the file "COPYING" in this distribution.
+ * A copy of the LGPL can be found in the file "COPYING.LESSER" in this distribution.
+ */
+#include "config.h"
+
+#include "rsyslog.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+
+#include "rsyslog.h"
+#include "obj.h"
+#include "module-template.h"
+#include "netstrm.h"
+#include "nspoll.h"
+
+/* static data */
+DEFobjStaticHelpers
+DEFobjCurrIf(glbl)
+
+
+/* load our low-level driver. This must be done before any
+ * driver-specific functions (allmost all...) can be carried
+ * out. Note that the driver's .ifIsLoaded is correctly
+ * initialized by calloc() and we depend on that. Please note that
+ * we do some name-mangeling. We know that each nsd driver also needs
+ * a nspoll driver. So we simply append "sel" to the nsd driver name: This, 
+ * of course, means that the driver name must match these rules, but that
+ * shouldn't be a real problem.
+ * WARNING: this code is mostly identical to similar code in 
+ * netstrms.c - TODO: abstract it and move it to some common place.
+ * rgerhards, 2008-04-28
+ */
+static rsRetVal
+loadDrvr(nspoll_t *pThis)
+{
+	DEFiRet;
+	uchar *pBaseDrvrName;
+	uchar szDrvrName[48]; /* 48 shall be large enough */
+
+	pBaseDrvrName = pThis->pBaseDrvrName;
+	if(pBaseDrvrName == NULL) /* if no drvr name is set, use system default */
+		pBaseDrvrName = glbl.GetDfltNetstrmDrvr();
+	if(snprintf((char*)szDrvrName, sizeof(szDrvrName), "lmnsdpoll_%s", pBaseDrvrName) == sizeof(szDrvrName))
+		ABORT_FINALIZE(RS_RET_DRVRNAME_TOO_LONG);
+	CHKmalloc(pThis->pDrvrName = (uchar*) strdup((char*)szDrvrName));
+
+	pThis->Drvr.ifVersion = nsdCURR_IF_VERSION;
+	/* The pDrvrName+2 below is a hack to obtain the object name. It 
+	 * safes us to have yet another variable with the name without "lm" in
+	 * front of it. If we change the module load interface, we may re-think
+	 * about this hack, but for the time being it is efficient and clean
+	 * enough. -- rgerhards, 2008-04-18
+	 */
+RUNLOG_VAR("%s", szDrvrName+2);
+	CHKiRet(obj.UseObj(__FILE__, szDrvrName+2, DONT_LOAD_LIB, (void*) &pThis->Drvr));
+
+finalize_it:
+	if(iRet != RS_RET_OK) {
+		if(pThis->pDrvrName != NULL)
+			free(pThis->pDrvrName);
+			pThis->pDrvrName = NULL;
+	}
+	RETiRet;
+}
+
+
+/* Standard-Constructor */
+BEGINobjConstruct(nspoll) /* be sure to specify the object type also in END macro! */
+ENDobjConstruct(nspoll)
+
+
+/* destructor for the nspoll object */
+BEGINobjDestruct(nspoll) /* be sure to specify the object type also in END and CODESTART macros! */
+CODESTARTobjDestruct(nspoll)
+	if(pThis->pDrvrData != NULL)
+		pThis->Drvr.Destruct(&pThis->pDrvrData);
+
+	/* and now we must release our driver, if we got one. We use the presence of
+	 * a driver name string as load indicator (because we also need that string
+	 * to release the driver 
+	 */
+	if(pThis->pDrvrName != NULL) {
+		obj.ReleaseObj(__FILE__, pThis->pDrvrName+2, DONT_LOAD_LIB, (void*) &pThis->Drvr);
+		free(pThis->pDrvrName);
+	}
+ENDobjDestruct(nspoll)
+
+
+/* ConstructionFinalizer */
+static rsRetVal
+ConstructFinalize(nspoll_t *pThis)
+{
+	DEFiRet;
+	ISOBJ_TYPE_assert(pThis, nspoll);
+RUNLOG_STR("trying to load epoll driver\n");
+	CHKiRet(loadDrvr(pThis));
+	CHKiRet(pThis->Drvr.Construct(&pThis->pDrvrData));
+finalize_it:
+dbgprintf("XXX: done trying to load epoll driver, state %d\n", iRet);
+	RETiRet;
+}
+
+
+/* Carries out the actual wait (all done in lower layers)
+ */
+static rsRetVal
+Wait(nspoll_t *pThis, int timeout, int *idRdy, void **ppUsr) {
+	DEFiRet;
+	ISOBJ_TYPE_assert(pThis, nspoll);
+	assert(idRdy != NULL);
+	iRet = pThis->Drvr.Wait(pThis->pDrvrData, timeout, idRdy, ppUsr);
+	RETiRet;
+}
+
+
+/* semantics like the epoll_ctl() function, does the same thing.
+ * rgerhards, 2009-11-18
+ */
+static rsRetVal
+Ctl(nspoll_t *pThis, netstrm_t *pStrm, int id, void *pUsr, int mode, int op) {
+	DEFiRet;
+	ISOBJ_TYPE_assert(pThis, nspoll);
+	iRet = pThis->Drvr.Ctl(pThis->pDrvrData, pStrm->pDrvrData, id, pUsr, mode, op);
+	RETiRet;
+}
+
+
+/* queryInterface function */
+BEGINobjQueryInterface(nspoll)
+CODESTARTobjQueryInterface(nspoll)
+	if(pIf->ifVersion != nspollCURR_IF_VERSION) {/* check for current version, increment on each change */
+		ABORT_FINALIZE(RS_RET_INTERFACE_NOT_SUPPORTED);
+	}
+
+	/* ok, we have the right interface, so let's fill it
+	 * Please note that we may also do some backwards-compatibility
+	 * work here (if we can support an older interface version - that,
+	 * of course, also affects the "if" above).
+	 */
+	pIf->Construct = nspollConstruct;
+	pIf->ConstructFinalize = ConstructFinalize;
+	pIf->Destruct = nspollDestruct;
+	pIf->Wait = Wait;
+	pIf->Ctl = Ctl;
+finalize_it:
+ENDobjQueryInterface(nspoll)
+
+
+/* exit our class
+ */
+BEGINObjClassExit(nspoll, OBJ_IS_LOADABLE_MODULE) /* CHANGE class also in END MACRO! */
+CODESTARTObjClassExit(nspoll)
+	/* release objects we no longer need */
+	objRelease(glbl, CORE_COMPONENT);
+ENDObjClassExit(nspoll)
+
+
+/* Initialize the nspoll class. Must be called as the very first method
+ * before anything else is called inside this class.
+ * rgerhards, 2008-02-19
+ */
+BEGINObjClassInit(nspoll, 1, OBJ_IS_CORE_MODULE) /* class, version */
+	/* request objects we use */
+	DBGPRINTF("doing nspollClassInit\n");
+	CHKiRet(objUse(glbl, CORE_COMPONENT));
+
+	/* set our own handlers */
+ENDObjClassInit(nspoll)
+/* vi:set ai:
+ */
diff --git a/runtime/nspoll.h b/runtime/nspoll.h
new file mode 100644
index 00000000..a77759c0
--- /dev/null
+++ b/runtime/nspoll.h
@@ -0,0 +1,65 @@
+/* Definitions for the nspoll io activity waiter
+ *
+ * Copyright 2009 Rainer Gerhards and Adiscon GmbH.
+ *
+ * This file is part of the rsyslog runtime library.
+ *
+ * The rsyslog runtime library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * The rsyslog runtime library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with the rsyslog runtime library.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * A copy of the GPL can be found in the file "COPYING" in this distribution.
+ * A copy of the LGPL can be found in the file "COPYING.LESSER" in this distribution.
+ */
+
+#ifndef INCLUDED_NSPOLL_H
+#define INCLUDED_NSPOLL_H
+
+#include "netstrms.h"
+
+/* some operations to be portable when we do not have epoll() available */
+#define NSDPOLL_ADD	1
+#define NSDPOLL_DEL	2
+
+/* and some mode specifiers for waiting on input/output */
+#define NSDPOLL_IN	1	/* EPOLLIN */
+#define NSDPOLL_OUT	2	/* EPOLLOUT */
+/* next is 4, 8, 16, ... - must be bit values, as they are ored! */
+
+/* the nspoll object */
+struct nspoll_s {
+	BEGINobjInstance;	/* Data to implement generic object - MUST be the first data element! */
+	nsd_t *pDrvrData;	/**< the driver's data elements */
+	uchar *pBaseDrvrName;	/**< nsd base driver name to use, or NULL if system default */
+	uchar *pDrvrName;	/**< full base driver name (set when driver is loaded) */
+	nsdpoll_if_t Drvr;	/**< our stream driver */
+};
+
+
+/* interface */
+BEGINinterface(nspoll) /* name must also be changed in ENDinterface macro! */
+	rsRetVal (*Construct)(nspoll_t **ppThis);
+	rsRetVal (*ConstructFinalize)(nspoll_t *pThis);
+	rsRetVal (*Destruct)(nspoll_t **ppThis);
+	rsRetVal (*Wait)(nspoll_t *pNsdpoll, int timeout, int *idRdy, void **ppUsr);
+	rsRetVal (*Ctl)(nspoll_t *pNsdpoll, netstrm_t *pStrm, int id, void *pUsr, int mode, int op);
+	rsRetVal (*IsEPollSupported)(void); /* static method */
+ENDinterface(nspoll)
+#define nspollCURR_IF_VERSION 1 /* increment whenever you change the interface structure! */
+
+/* prototypes */
+PROTOTYPEObj(nspoll);
+
+/* the name of our library binary */
+#define LM_NSPOLL_FILENAME LM_NETSTRMS_FILENAME
+
+#endif /* #ifndef INCLUDED_NSPOLL_H */
diff --git a/runtime/nssel.c b/runtime/nssel.c
index d11d5fe1..7c5be3a9 100644
--- a/runtime/nssel.c
+++ b/runtime/nssel.c
@@ -219,6 +219,7 @@ ENDObjClassExit(nssel)
  */
 BEGINObjClassInit(nssel, 1, OBJ_IS_CORE_MODULE) /* class, version */
 	/* request objects we use */
+	DBGPRINTF("doing nsselClassInit\n");
 	CHKiRet(objUse(glbl, CORE_COMPONENT));
 
 	/* set our own handlers */
diff --git a/runtime/rsyslog.h b/runtime/rsyslog.h
index a5e8cf5d..1431c684 100644
--- a/runtime/rsyslog.h
+++ b/runtime/rsyslog.h
@@ -107,6 +107,7 @@ typedef struct NetAddr netAddr_t;
 typedef struct netstrms_s netstrms_t;
 typedef struct netstrm_s netstrm_t;
 typedef struct nssel_s nssel_t;
+typedef struct nspoll_s nspoll_t;
 typedef enum nsdsel_waitOp_e nsdsel_waitOp_t;
 typedef struct nsd_ptcp_s nsd_ptcp_t;
 typedef struct nsd_gtls_s nsd_gtls_t;
@@ -114,9 +115,11 @@ typedef struct nsd_gsspi_s nsd_gsspi_t;
 typedef struct nsd_nss_s nsd_nss_t;
 typedef struct nsdsel_ptcp_s nsdsel_ptcp_t;
 typedef struct nsdsel_gtls_s nsdsel_gtls_t;
+typedef struct nsdpoll_ptcp_s nsdpoll_ptcp_t;
 typedef struct wti_s wti_t;
 typedef obj_t nsd_t;
 typedef obj_t nsdsel_t;
+typedef obj_t nsdpoll_t;
 typedef struct msg msg_t;
 typedef struct queue_s qqueue_t;
 typedef struct prop_s prop_t;
@@ -148,6 +151,8 @@ typedef unsigned int u_int32_t; /* TODO: is this correct? */
 typedef int socklen_t;
 #endif
 
+typedef struct epoll_event epoll_event_t;
+
 typedef char bool;		/* I intentionally use char, to keep it slim so that many fit into the CPU cache! */
 
 /* settings for flow control
@@ -409,6 +414,11 @@ enum rsRetVal_				/** return value. All methods return this if not specified oth
 	RS_RET_NO_RULESET= -2158,/**< no ruleset name as specified where one was needed */
 	RS_RET_PARSER_NOT_FOUND = -2159,/**< parser with the specified name was not found */
 	RS_RET_COULD_NOT_PARSE = -2160,/**< (this) parser could not parse the message (no error, means try next one) */
+	RS_RET_EINTR = -2161,		/**< EINTR occured during a system call (not necessarily an error) */
+	RS_RET_ERR_EPOLL = -2162,	/**< epoll() returned with an unexpected error code */
+	RS_RET_ERR_EPOLL_CTL = -2163,	/**< epol_ctll() returned with an unexpected error code */
+	RS_RET_TIMEOUT = -2164,		/**< timeout occured during operation */
+	RS_RET_RCV_ERR = -2165,		/**< error occured during socket rcv operation */
 
 	/* RainerScript error messages (range 1000.. 1999) */
 	RS_RET_SYSVAR_NOT_FOUND = 1001, /**< system variable could not be found (maybe misspelled) */