added skeleton for supporting epoll() API in netstream subsystem

1 files changed, 196 insertions, 0 deletions

diff --git a/runtime/nspoll.c b/runtime/nspoll.c
new file mode 100644
index 00000000..ff0b1e92
--- /dev/null
+++ b/runtime/nspoll.c
@@ -0,0 +1,196 @@
+/* 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), "lmnspoll_%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
+	 */
+	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);
+	CHKiRet(loadDrvr(pThis));
+	CHKiRet(pThis->Drvr.Construct(&pThis->pDrvrData));
+finalize_it:
+	RETiRet;
+}
+
+
+/* Carries out the actual wait (all done in lower layers)
+ */
+static rsRetVal
+Wait(nspoll_t *pThis, epoll_event_t *events, int maxevents, int timeout) {
+	DEFiRet;
+	ISOBJ_TYPE_assert(pThis, nspoll);
+	assert(events != NULL);
+	assert(maxevents > 0);
+	iRet = pThis->Drvr.Wait(pThis->pDrvrData, events, maxevents, timeout);
+	RETiRet;
+}
+
+
+/* semantics like the epoll_ctl() function, does the same thing.
+ * rgerhards, 2009-11-18
+ */
+static rsRetVal
+Ctl(nspoll_t *pThis, int fd, int op, epoll_event_t *event) {
+	DEFiRet;
+	ISOBJ_TYPE_assert(pThis, nspoll);
+	assert(event != NULL);
+	iRet = pThis->Drvr.Ctl(pThis->pDrvrData, fd, op, event);
+	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 */
+	CHKiRet(objUse(glbl, CORE_COMPONENT));
+
+	/* set our own handlers */
+ENDObjClassInit(nspoll)
+/* vi:set ai:
+ */