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Diffstat (limited to 'runtime/nssel.c')
| -rw-r--r-- | runtime/nssel.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/runtime/nssel.c b/runtime/nssel.c new file mode 100644 index 0000000..d11d5fe --- /dev/null +++ b/runtime/nssel.c @@ -0,0 +1,227 @@ +/* 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 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 "nssel.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(); + 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 + */ + 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; +} + + +/* 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 *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->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 */ + CHKiRet(objUse(glbl, CORE_COMPONENT)); + + /* set our own handlers */ +ENDObjClassInit(nssel) +/* vi:set ai: + */ |