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+/* nssel.c
+ *
+ * The io waiter is a helper object enabling us to wait on a set of streams to become
+ * ready for IO - this is modelled after select(). We need this, because
+ * stream drivers may have different concepts. Consequently,
+ * the structure must contain nsd_t's from the same stream driver type
+ * only. This is implemented as a singly-linked list where every
+ * new element is added at the top of the list.
+ *
+ * Work on this module begun 2008-04-22 by Rainer Gerhards.
+ *
+ * Copyright 2008-2014 Adiscon GmbH.
+ *
+ * This file is part of the rsyslog runtime library.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * -or-
+ * see COPYING.ASL20 in the source distribution
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#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 "nssel.h"
+#include "rsconf.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 nssel 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(nssel_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(runConf);
+ if(snprintf((char*)szDrvrName, sizeof(szDrvrName), "lmnsdsel_%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(nssel) /* be sure to specify the object type also in END macro! */
+ENDobjConstruct(nssel)
+
+
+/* destructor for the nssel object */
+BEGINobjDestruct(nssel) /* be sure to specify the object type also in END and CODESTART macros! */
+CODESTARTobjDestruct(nssel)
+ 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
+ */
+ free(pThis->pBaseDrvrName);
+ if(pThis->pDrvrName != NULL) {
+ obj.ReleaseObj(__FILE__, pThis->pDrvrName+2, DONT_LOAD_LIB, (void*) &pThis->Drvr);
+ free(pThis->pDrvrName);
+ }
+ENDobjDestruct(nssel)
+
+
+/* ConstructionFinalizer */
+static rsRetVal
+ConstructFinalize(nssel_t *pThis)
+{
+ DEFiRet;
+ ISOBJ_TYPE_assert(pThis, nssel);
+ CHKiRet(loadDrvr(pThis));
+ CHKiRet(pThis->Drvr.Construct(&pThis->pDrvrData));
+finalize_it:
+ RETiRet;
+}
+
+
+/* set the base driver name. If the driver name
+ * is set to NULL, the previously set name is deleted but
+ * no name set again (which results in the system default being
+ * used)-- rgerhards, 2008-05-05
+ */
+static rsRetVal
+SetDrvrName(nssel_t *pThis, uchar *pszName)
+{
+ DEFiRet;
+ ISOBJ_TYPE_assert(pThis, nssel);
+ if(pThis->pBaseDrvrName != NULL) {
+ free(pThis->pBaseDrvrName);
+ pThis->pBaseDrvrName = NULL;
+ }
+
+ if(pszName != NULL) {
+ CHKmalloc(pThis->pBaseDrvrName = (uchar*) strdup((char*) pszName));
+ }
+finalize_it:
+ RETiRet;
+}
+
+
+/* Add a stream object to the current select() set.
+ * Note that a single stream may have multiple "sockets" if
+ * it is a listener. If so, all of them are begin added.
+ */
+static rsRetVal
+Add(nssel_t *pThis, netstrm_t *pStrm, nsdsel_waitOp_t waitOp)
+{
+ DEFiRet;
+
+ ISOBJ_TYPE_assert(pThis, nssel);
+ ISOBJ_TYPE_assert(pStrm, netstrm);
+
+ CHKiRet(pThis->Drvr.Add(pThis->pDrvrData, pStrm->pDrvrData, waitOp));
+
+finalize_it:
+ RETiRet;
+}
+
+
+/* wait for IO to happen on one of our netstreams. iNumReady has
+ * the number of ready "sockets" after the call. This function blocks
+ * until some are ready. EAGAIN is retried.
+ */
+static rsRetVal
+Wait(nssel_t *pThis, int *piNumReady)
+{
+ DEFiRet;
+ ISOBJ_TYPE_assert(pThis, nssel);
+ assert(piNumReady != NULL);
+ iRet = pThis->Drvr.Select(pThis->pDrvrData, piNumReady);
+ RETiRet;
+}
+
+
+/* Check if a stream is ready for IO. *piNumReady contains the remaining number
+ * of ready streams. Note that this function may say the stream is not ready
+ * but still decrement *piNumReady. This can happen when (e.g. with TLS) the low
+ * level driver requires some IO which is hidden from the upper layer point of view.
+ * rgerhards, 2008-04-23
+ */
+static rsRetVal
+IsReady(nssel_t *pThis, netstrm_t *pStrm, nsdsel_waitOp_t waitOp, int *pbIsReady,
+int __attribute__((unused)) *piNumReady)
+{
+ DEFiRet;
+ ISOBJ_TYPE_assert(pThis, nssel);
+ ISOBJ_TYPE_assert(pStrm, netstrm);
+ assert(pbIsReady != NULL);
+ assert(piNumReady != NULL);
+ iRet = pThis->Drvr.IsReady(pThis->pDrvrData, pStrm->pDrvrData, waitOp, pbIsReady);
+ RETiRet;
+}
+
+
+/* queryInterface function */
+BEGINobjQueryInterface(nssel)
+CODESTARTobjQueryInterface(nssel)
+ if(pIf->ifVersion != nsselCURR_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 = nsselConstruct;
+ pIf->ConstructFinalize = ConstructFinalize;
+ pIf->Destruct = nsselDestruct;
+ pIf->SetDrvrName = SetDrvrName;
+ pIf->Add = Add;
+ pIf->Wait = Wait;
+ pIf->IsReady = IsReady;
+finalize_it:
+ENDobjQueryInterface(nssel)
+
+
+/* exit our class
+ */
+BEGINObjClassExit(nssel, OBJ_IS_LOADABLE_MODULE) /* CHANGE class also in END MACRO! */
+CODESTARTObjClassExit(nssel)
+ /* release objects we no longer need */
+ objRelease(glbl, CORE_COMPONENT);
+ENDObjClassExit(nssel)
+
+
+/* Initialize the nssel class. Must be called as the very first method
+ * before anything else is called inside this class.
+ * rgerhards, 2008-02-19
+ */
+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 */
+ENDObjClassInit(nssel)
+/* vi:set ai:
+ */