Imported Upstream version 3.14.1upstream/3.14.1

1 files changed, 622 insertions, 0 deletions

diff --git a/wtp.c b/wtp.c
new file mode 100644
index 0000000..1c2ea30
--- /dev/null
+++ b/wtp.c
@@ -0,0 +1,622 @@
+/* wtp.c
+ *
+ * This file implements the worker thread pool (wtp) class.
+ * 
+ * File begun on 2008-01-20 by RGerhards
+ *
+ * There is some in-depth documentation available in doc/dev_queue.html
+ * (and in the web doc set on http://www.rsyslog.com/doc). Be sure to read it
+ * if you are getting aquainted to the object.
+ *
+ * Copyright 2008 Rainer Gerhards and Adiscon GmbH.
+ *
+ * This file is part of rsyslog.
+ *
+ * Rsyslog is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Rsyslog 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Rsyslog.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * A copy of the GPL can be found in the file "COPYING" in this distribution.
+ */
+#include "config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <signal.h>
+#include <pthread.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "rsyslog.h"
+#include "syslogd.h"
+#include "stringbuf.h"
+#include "srUtils.h"
+#include "wtp.h"
+#include "wti.h"
+#include "obj.h"
+
+/* static data */
+DEFobjStaticHelpers
+
+/* forward-definitions */
+
+/* methods */
+
+/* get the header for debug messages
+ * The caller must NOT free or otherwise modify the returned string!
+ */
+static inline uchar *
+wtpGetDbgHdr(wtp_t *pThis)
+{
+	ISOBJ_TYPE_assert(pThis, wtp);
+
+	if(pThis->pszDbgHdr == NULL)
+		return (uchar*) "wtp"; /* should not normally happen */
+	else
+		return pThis->pszDbgHdr;
+}
+
+
+
+/* Not implemented dummy function for constructor */
+static rsRetVal NotImplementedDummy() { return RS_RET_OK; }
+/* Standard-Constructor for the wtp object
+ */
+BEGINobjConstruct(wtp) /* be sure to specify the object type also in END macro! */
+	pthread_mutex_init(&pThis->mut, NULL);
+	pthread_cond_init(&pThis->condThrdTrm, NULL);
+	/* set all function pointers to "not implemented" dummy so that we can safely call them */
+	pThis->pfChkStopWrkr = NotImplementedDummy;
+	pThis->pfIsIdle = NotImplementedDummy;
+	pThis->pfDoWork = NotImplementedDummy;
+	pThis->pfOnIdle = NotImplementedDummy;
+	pThis->pfOnWorkerCancel = NotImplementedDummy;
+	pThis->pfOnWorkerStartup = NotImplementedDummy;
+	pThis->pfOnWorkerShutdown = NotImplementedDummy;
+ENDobjConstruct(wtp)
+
+
+/* Construction finalizer
+ * rgerhards, 2008-01-17
+ */
+rsRetVal
+wtpConstructFinalize(wtp_t *pThis)
+{
+	DEFiRet;
+	int i;
+	uchar pszBuf[64];
+	size_t lenBuf;
+	wti_t *pWti;
+
+	ISOBJ_TYPE_assert(pThis, wtp);
+
+	dbgprintf("%s: finalizing construction of worker thread pool\n", wtpGetDbgHdr(pThis));
+	/* alloc and construct workers - this can only be done in finalizer as we previously do
+	 * not know the max number of workers
+	 */
+	if((pThis->pWrkr = malloc(sizeof(wti_t*) * pThis->iNumWorkerThreads)) == NULL)
+		ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY);
+
+	for(i = 0 ; i < pThis->iNumWorkerThreads ; ++i) {
+		CHKiRet(wtiConstruct(&pThis->pWrkr[i]));
+		pWti = pThis->pWrkr[i];
+		lenBuf = snprintf((char*)pszBuf, sizeof(pszBuf), "%s/w%d", wtpGetDbgHdr(pThis), i);
+		CHKiRet(wtiSetDbgHdr(pWti, pszBuf, lenBuf));
+		CHKiRet(wtiSetpWtp(pWti, pThis));
+		CHKiRet(wtiConstructFinalize(pWti));
+	}
+		
+
+finalize_it:
+	RETiRet;
+}
+
+
+/* Destructor */
+BEGINobjDestruct(wtp) /* be sure to specify the object type also in END and CODESTART macros! */
+	int i;
+CODESTARTobjDestruct(wtp)
+	wtpProcessThrdChanges(pThis); /* process thread changes one last time */
+
+	/* destruct workers */
+	for(i = 0 ; i < pThis->iNumWorkerThreads ; ++i)
+		wtiDestruct(&pThis->pWrkr[i]);
+
+	free(pThis->pWrkr);
+	pThis->pWrkr = NULL;
+
+	/* actual destruction */
+	pthread_cond_destroy(&pThis->condThrdTrm);
+	pthread_mutex_destroy(&pThis->mut);
+
+	if(pThis->pszDbgHdr != NULL)
+		free(pThis->pszDbgHdr);
+ENDobjDestruct(wtp)
+
+
+/* wake up at least one worker thread.
+ * rgerhards, 2008-01-20
+ */
+rsRetVal
+wtpWakeupWrkr(wtp_t *pThis)
+{
+	DEFiRet;
+
+	/* TODO; mutex? I think not needed, as we do not need predictable exec order -- rgerhards, 2008-01-28 */
+	ISOBJ_TYPE_assert(pThis, wtp);
+	pthread_cond_signal(pThis->pcondBusy);
+	RETiRet;
+}
+
+/* wake up all worker threads.
+ * rgerhards, 2008-01-16
+ */
+rsRetVal
+wtpWakeupAllWrkr(wtp_t *pThis)
+{
+	DEFiRet;
+
+	ISOBJ_TYPE_assert(pThis, wtp);
+	pthread_cond_broadcast(pThis->pcondBusy);
+	RETiRet;
+}
+
+
+/* check if we had any worker thread changes and, if so, act
+ * on them. At a minimum, terminated threads are harvested (joined).
+ * This function MUST NEVER block on the queue mutex!
+ */
+rsRetVal
+wtpProcessThrdChanges(wtp_t *pThis)
+{
+	DEFiRet;
+	int i;
+
+	ISOBJ_TYPE_assert(pThis, wtp);
+
+	if(pThis->bThrdStateChanged == 0)
+		FINALIZE;
+
+	/* go through all threads */
+	for(i = 0 ; i < pThis->iNumWorkerThreads ; ++i) {
+		wtiProcessThrdChanges(pThis->pWrkr[i], LOCK_MUTEX);
+	}
+
+finalize_it:
+	RETiRet;
+}
+
+
+/* Sent a specific state for the worker thread pool.
+ * rgerhards, 2008-01-21
+ */
+rsRetVal
+wtpSetState(wtp_t *pThis, wtpState_t iNewState)
+{
+	DEFiRet;
+
+	ISOBJ_TYPE_assert(pThis, wtp);
+	pThis->wtpState = iNewState;
+	/* TODO: must wakeup workers? seen to be not needed -- rgerhards, 2008-01-28 */
+
+	RETiRet;
+}
+
+
+/* check if the worker shall shutdown (1 = yes, 0 = no)
+ * TODO: check if we can use atomic operations to enhance performance
+ * Note: there may be two mutexes locked, the bLockUsrMutex is the one in our "user"
+ * (e.g. the queue clas)
+ * rgerhards, 2008-01-21
+ */
+rsRetVal
+wtpChkStopWrkr(wtp_t *pThis, int bLockMutex, int bLockUsrMutex)
+{
+	DEFiRet;
+	DEFVARS_mutexProtection;
+
+	ISOBJ_TYPE_assert(pThis, wtp);
+
+	BEGIN_MTX_PROTECTED_OPERATIONS(&pThis->mut, bLockMutex);
+	if(   (pThis->wtpState == wtpState_SHUTDOWN_IMMEDIATE)
+	   || ((pThis->wtpState == wtpState_SHUTDOWN) && pThis->pfIsIdle(pThis->pUsr, bLockUsrMutex)))
+		iRet = RS_RET_TERMINATE_NOW;
+	END_MTX_PROTECTED_OPERATIONS(&pThis->mut);
+
+	/* try customer handler if one was set and we do not yet have a definite result */
+	if(iRet == RS_RET_OK && pThis->pfChkStopWrkr != NULL) {
+		iRet = pThis->pfChkStopWrkr(pThis->pUsr, bLockUsrMutex);
+	}
+
+	RETiRet;
+}
+
+
+/* Send a shutdown command to all workers and see if they terminate.
+ * A timeout may be specified.
+ * rgerhards, 2008-01-14
+ */
+rsRetVal
+wtpShutdownAll(wtp_t *pThis, wtpState_t tShutdownCmd, struct timespec *ptTimeout)
+{
+	DEFiRet;
+	int bTimedOut;
+	int iCancelStateSave;
+
+	ISOBJ_TYPE_assert(pThis, wtp);
+
+	wtpSetState(pThis, tShutdownCmd);
+	wtpWakeupAllWrkr(pThis);
+
+	/* see if we need to harvest (join) any terminated threads (even in timeout case,
+	 * some may have terminated...
+	 */
+	wtpProcessThrdChanges(pThis);
+		
+	/* and wait for their termination */
+	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &iCancelStateSave);
+	d_pthread_mutex_lock(&pThis->mut);
+	pthread_cleanup_push(mutexCancelCleanup, &pThis->mut);
+	pthread_setcancelstate(iCancelStateSave, NULL);
+	bTimedOut = 0;
+	while(pThis->iCurNumWrkThrd > 0 && !bTimedOut) {
+		dbgprintf("%s: waiting %ldms on worker thread termination, %d still running\n",
+			   wtpGetDbgHdr(pThis), timeoutVal(ptTimeout), pThis->iCurNumWrkThrd);
+
+		if(d_pthread_cond_timedwait(&pThis->condThrdTrm, &pThis->mut, ptTimeout) != 0) {
+			dbgprintf("%s: timeout waiting on worker thread termination\n", wtpGetDbgHdr(pThis));
+			bTimedOut = 1;	/* we exit the loop on timeout */
+		}
+	}
+	pthread_cleanup_pop(1);
+
+	if(bTimedOut)
+		iRet = RS_RET_TIMED_OUT;
+	
+	/* see if we need to harvest (join) any terminated threads (even in timeout case,
+	 * some may have terminated...
+	 */
+	wtpProcessThrdChanges(pThis);
+
+	RETiRet;
+}
+
+
+/* indicate that a thread has terminated and awake anyone waiting on it
+ * rgerhards, 2008-01-23
+ */
+rsRetVal wtpSignalWrkrTermination(wtp_t *pThis)
+{
+	DEFiRet;
+	/* I leave the mutex code here out as it give as deadlocks. I think it is not really
+	 * needed and we are on the safe side. I leave this comment in if practice proves us
+	 * wrong. The whole thing should be removed after half a your or year if we see there
+	 * actually is no issue (or revisit it from a theoretical POV).
+	 * rgerhards, 2008-01-28
+	 */
+	/*TODO: mutex or not mutex, that's the question ;)DEFVARS_mutexProtection;*/
+
+	ISOBJ_TYPE_assert(pThis, wtp);
+
+	/*BEGIN_MTX_PROTECTED_OPERATIONS(&pThis->mut, LOCK_MUTEX);*/
+	pthread_cond_signal(&pThis->condThrdTrm); /* activate anyone waiting on thread shutdown */
+	/*END_MTX_PROTECTED_OPERATIONS(&pThis->mut);*/
+	RETiRet;
+}
+
+
+/* Unconditionally cancel all running worker threads.
+ * rgerhards, 2008-01-14
+ */
+rsRetVal
+wtpCancelAll(wtp_t *pThis)
+{
+	DEFiRet;
+	int i;
+
+	ISOBJ_TYPE_assert(pThis, wtp);
+
+	/* process any pending thread requests so that we know who actually is still running */
+	wtpProcessThrdChanges(pThis);
+
+	/* go through all workers and cancel those that are active */
+	for(i = 0 ; i < pThis->iNumWorkerThreads ; ++i) {
+		dbgprintf("%s: try canceling worker thread %d\n", wtpGetDbgHdr(pThis), i);
+		wtiCancelThrd(pThis->pWrkr[i]);
+	}
+
+	RETiRet;
+}
+
+
+
+/* Set the Inactivity Guard
+ * rgerhards, 2008-01-21
+ */
+rsRetVal
+wtpSetInactivityGuard(wtp_t *pThis, int bNewState, int bLockMutex)
+{
+	DEFiRet;
+	DEFVARS_mutexProtection;
+
+	BEGIN_MTX_PROTECTED_OPERATIONS(&pThis->mut, bLockMutex);
+	pThis->bInactivityGuard = bNewState;
+	END_MTX_PROTECTED_OPERATIONS(&pThis->mut);
+
+	RETiRet;
+}
+
+
+/* cancellation cleanup handler for executing worker
+ * decrements the worker counter
+ * rgerhards, 2008-01-20
+ */
+void
+wtpWrkrExecCancelCleanup(void *arg)
+{
+	wtp_t *pThis = (wtp_t*) arg;
+
+	BEGINfunc
+	ISOBJ_TYPE_assert(pThis, wtp);
+	pThis->iCurNumWrkThrd--;
+	wtpSignalWrkrTermination(pThis);
+
+	dbgprintf("%s: thread CANCELED with %d workers running.\n", wtpGetDbgHdr(pThis), pThis->iCurNumWrkThrd);
+	ENDfunc
+}
+
+
+/* wtp worker shell. This is started and calls into the actual
+ * wti worker.
+ * rgerhards, 2008-01-21
+ */
+static void *
+wtpWorker(void *arg) /* the arg is actually a wti object, even though we are in wtp! */
+{
+	DEFiRet;
+	DEFVARS_mutexProtection;
+	wti_t *pWti = (wti_t*) arg;
+	wtp_t *pThis;
+	sigset_t sigSet;
+
+	ISOBJ_TYPE_assert(pWti, wti);
+	pThis = pWti->pWtp;
+	ISOBJ_TYPE_assert(pThis, wtp);
+
+	sigfillset(&sigSet);
+	pthread_sigmask(SIG_BLOCK, &sigSet, NULL);
+
+	BEGIN_MTX_PROTECTED_OPERATIONS(&pThis->mut, LOCK_MUTEX);
+
+	/* do some late initialization */
+
+	pthread_cleanup_push(wtpWrkrExecCancelCleanup, pThis);
+
+	/* finally change to RUNNING state. We need to check if we actually should still run,
+	 * because someone may have requested us to shut down even before we got a chance to do
+	 * our init. That would be a bad race... -- rgerhards, 2008-01-16
+	 */
+	wtiSetState(pWti, eWRKTHRD_RUNNING, 0, MUTEX_ALREADY_LOCKED); /* we are running now! */
+
+	do {
+		END_MTX_PROTECTED_OPERATIONS(&pThis->mut);
+
+		iRet = wtiWorker(pWti); /* just to make sure: this is NOT protected by the mutex! */
+
+		BEGIN_MTX_PROTECTED_OPERATIONS(&pThis->mut, LOCK_MUTEX);
+	} while(pThis->iCurNumWrkThrd == 1 && pThis->bInactivityGuard == 1);
+	/* inactivity guard prevents shutdown of all workers while one should be running due to race
+	 * condition. It can lead to one more worker running than desired, but that is acceptable. After
+	 * all, that worker will shutdown itself due to inactivity timeout. If, however, none were running
+	 * when one was required, processing could come to a halt. -- rgerhards, 2008-01-21
+	 */
+
+	pthread_cleanup_pop(0);
+	pThis->iCurNumWrkThrd--;
+	wtpSignalWrkrTermination(pThis);
+
+	dbgprintf("%s: Worker thread %lx, terminated, num workers now %d\n",
+		  wtpGetDbgHdr(pThis), (unsigned long) pWti, pThis->iCurNumWrkThrd);
+
+	END_MTX_PROTECTED_OPERATIONS(&pThis->mut);
+
+	ENDfunc
+	pthread_exit(0);
+}
+
+
+/* start a new worker */
+static rsRetVal
+wtpStartWrkr(wtp_t *pThis, int bLockMutex)
+{
+	DEFiRet;
+	DEFVARS_mutexProtection;
+	wti_t *pWti;
+	int i;
+	int iState;
+
+	ISOBJ_TYPE_assert(pThis, wtp);
+
+	wtpProcessThrdChanges(pThis);
+
+	BEGIN_MTX_PROTECTED_OPERATIONS(&pThis->mut, bLockMutex);
+
+	pThis->iCurNumWrkThrd++;
+
+	/* find free spot in thread table. If we find at least one worker that is in initialization,
+	 * we do NOT start a new one. Let's give the other one a chance, first.
+	 */
+	for(i = 0 ; i < pThis->iNumWorkerThreads ; ++i) {
+		if(wtiGetState(pThis->pWrkr[i], LOCK_MUTEX) == eWRKTHRD_STOPPED) {
+			break;
+		}
+	}
+
+	if(i == pThis->iNumWorkerThreads)
+		ABORT_FINALIZE(RS_RET_NO_MORE_THREADS);
+
+	pWti = pThis->pWrkr[i];
+	wtiSetState(pWti, eWRKTHRD_RUN_CREATED, 0, LOCK_MUTEX);
+	iState = pthread_create(&(pWti->thrdID), NULL, wtpWorker, (void*) pWti);
+	dbgprintf("%s: started with state %d, num workers now %d\n",
+		  wtpGetDbgHdr(pThis), iState, pThis->iCurNumWrkThrd);
+
+	/* we try to give the starting worker a little boost. It won't help much as we still
+ 	 * hold the queue's mutex, but at least it has a chance to start on a single-CPU system.
+ 	 */
+#	if !defined(__hpux) /* pthread_yield is missing there! */
+	pthread_yield();
+#	endif
+
+	/* indicate we just started a worker and would like to see it running */
+	wtpSetInactivityGuard(pThis, 1, MUTEX_ALREADY_LOCKED);
+
+finalize_it:
+	END_MTX_PROTECTED_OPERATIONS(&pThis->mut);
+	RETiRet;
+}
+
+
+/* set the number of worker threads that should be running. If less than currently running,
+ * a new worker may be started. Please note that there is no guarantee the number of workers
+ * said will be running after we exit this function. It is just a hint. If the number is
+ * higher than one, and no worker is started, the "busy" condition is signaled to awake a worker.
+ * So the caller can assume that there is at least one worker re-checking if there is "work to do"
+ * after this function call.
+ * rgerhards, 2008-01-21
+ */
+rsRetVal
+wtpAdviseMaxWorkers(wtp_t *pThis, int nMaxWrkr)
+{
+	DEFiRet;
+	DEFVARS_mutexProtection;
+	int nMissing; /* number workers missing to run */
+	int i;
+
+	ISOBJ_TYPE_assert(pThis, wtp);
+
+	if(nMaxWrkr == 0)
+		FINALIZE;
+
+	BEGIN_MTX_PROTECTED_OPERATIONS(&pThis->mut, LOCK_MUTEX);
+
+	if(nMaxWrkr > pThis->iNumWorkerThreads) /* limit to configured maximum */
+		nMaxWrkr = pThis->iNumWorkerThreads;
+
+	nMissing = nMaxWrkr - pThis->iCurNumWrkThrd;
+
+	if(nMissing > 0) {
+		dbgprintf("%s: high activity - starting %d additional worker thread(s).\n", wtpGetDbgHdr(pThis), nMissing);
+		/* start the rqtd nbr of workers */
+		for(i = 0 ; i < nMissing ; ++i) {
+			CHKiRet(wtpStartWrkr(pThis, MUTEX_ALREADY_LOCKED));
+		}
+	} else  {
+		if(nMaxWrkr > 0) {
+	dbgprintf("wtpAdviseMaxWorkers signals busy\n");
+			wtpWakeupWrkr(pThis);
+		}
+	}
+
+	
+finalize_it:
+	END_MTX_PROTECTED_OPERATIONS(&pThis->mut);
+	RETiRet;
+}
+
+
+/* some simple object access methods */
+DEFpropSetMeth(wtp, toWrkShutdown, long);
+DEFpropSetMeth(wtp, wtpState, wtpState_t);
+DEFpropSetMeth(wtp, iNumWorkerThreads, int);
+DEFpropSetMeth(wtp, pUsr, void*);
+DEFpropSetMethPTR(wtp, pmutUsr, pthread_mutex_t);
+DEFpropSetMethPTR(wtp, pcondBusy, pthread_cond_t);
+DEFpropSetMethFP(wtp, pfChkStopWrkr, rsRetVal(*pVal)(void*, int));
+DEFpropSetMethFP(wtp, pfIsIdle, rsRetVal(*pVal)(void*, int));
+DEFpropSetMethFP(wtp, pfDoWork, rsRetVal(*pVal)(void*, void*, int));
+DEFpropSetMethFP(wtp, pfOnIdle, rsRetVal(*pVal)(void*, int));
+DEFpropSetMethFP(wtp, pfOnWorkerCancel, rsRetVal(*pVal)(void*, void*));
+DEFpropSetMethFP(wtp, pfOnWorkerStartup, rsRetVal(*pVal)(void*));
+DEFpropSetMethFP(wtp, pfOnWorkerShutdown, rsRetVal(*pVal)(void*));
+
+
+/* return the current number of worker threads.
+ * TODO: atomic operation would bring a nice performance
+ * enhancemcent
+ * rgerhards, 2008-01-27
+ */
+int
+wtpGetCurNumWrkr(wtp_t *pThis, int bLockMutex)
+{
+	DEFVARS_mutexProtection;
+	int iNumWrkr;
+
+	BEGINfunc
+	ISOBJ_TYPE_assert(pThis, wtp);
+
+	BEGIN_MTX_PROTECTED_OPERATIONS(&pThis->mut, bLockMutex);
+	iNumWrkr = pThis->iCurNumWrkThrd;
+	END_MTX_PROTECTED_OPERATIONS(&pThis->mut);
+
+	ENDfunc
+	return iNumWrkr;
+}
+
+
+/* set the debug header message
+ * The passed-in string is duplicated. So if the caller does not need
+ * it any longer, it must free it. Must be called only before object is finalized.
+ * rgerhards, 2008-01-09
+ */
+rsRetVal
+wtpSetDbgHdr(wtp_t *pThis, uchar *pszMsg, size_t lenMsg)
+{
+	DEFiRet;
+
+	ISOBJ_TYPE_assert(pThis, wtp);
+	assert(pszMsg != NULL);
+	
+	if(lenMsg < 1)
+		ABORT_FINALIZE(RS_RET_PARAM_ERROR);
+
+	if(pThis->pszDbgHdr != NULL) {
+		free(pThis->pszDbgHdr);
+		pThis->pszDbgHdr = NULL;
+	}
+
+	if((pThis->pszDbgHdr = malloc(sizeof(uchar) * lenMsg + 1)) == NULL)
+		ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY);
+
+	memcpy(pThis->pszDbgHdr, pszMsg, lenMsg + 1); /* always think about the \0! */
+
+finalize_it:
+	RETiRet;
+}
+
+/* dummy */
+rsRetVal wtpQueryInterface(void) { return RS_RET_NOT_IMPLEMENTED; }
+
+/* Initialize the stream class. Must be called as the very first method
+ * before anything else is called inside this class.
+ * rgerhards, 2008-01-09
+ */
+BEGINObjClassInit(wtp, 1, OBJ_IS_CORE_MODULE)
+	/* request objects we use */
+ENDObjClassInit(wtp)
+
+/*
+ * vi:set ai:
+ */