Merge remote branch 'upstream/master'

1 files changed, 284 insertions, 0 deletions

diff --git a/threads.c b/threads.c
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+/* threads.c
+ *
+ * This file implements threading support helpers (and maybe the thread object)
+ * for rsyslog.
+ * 
+ * File begun on 2007-12-14 by RGerhards
+ *
+ * Copyright 2007-2012 Adiscon GmbH.
+ *
+ * This file is part of rsyslog.
+ *
+ * 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 <stdlib.h>
+#include <string.h>
+#include <signal.h>
+#include <errno.h>
+#include <pthread.h>
+#include <assert.h>
+#if HAVE_SYS_PRCTL_H
+#  include <sys/prctl.h>
+#endif
+
+#include "rsyslog.h"
+#include "dirty.h"
+#include "linkedlist.h"
+#include "threads.h"
+#include "srUtils.h"
+#include "unicode-helper.h"
+
+/* linked list of currently-known threads */
+static linkedList_t llThrds;
+
+/* methods */
+
+/* Construct a new thread object
+ */
+static rsRetVal
+thrdConstruct(thrdInfo_t **ppThis)
+{
+	DEFiRet;
+	thrdInfo_t *pThis;
+
+	assert(ppThis != NULL);
+
+	CHKmalloc(pThis = calloc(1, sizeof(thrdInfo_t)));
+	pthread_mutex_init(&pThis->mutThrd, NULL);
+	pthread_cond_init(&pThis->condThrdTerm, NULL);
+	*ppThis = pThis;
+
+finalize_it:
+	RETiRet;
+}
+
+
+/* Destructs a thread object. The object must not be linked to the
+ * linked list of threads. Please note that the thread should have been
+ * stopped before. If not, we try to do it.
+ */
+static rsRetVal thrdDestruct(thrdInfo_t *pThis)
+{
+	DEFiRet;
+	assert(pThis != NULL);
+
+	if(pThis->bIsActive == 1) {
+		thrdTerminate(pThis);
+	}
+	pthread_mutex_destroy(&pThis->mutThrd);
+	pthread_cond_destroy(&pThis->condThrdTerm);
+	free(pThis->name);
+	free(pThis);
+
+	RETiRet;
+}
+
+
+/* terminate a thread via the non-cancel interface
+ * This is a separate function as it involves a bit more of code.
+ * rgerhads, 2009-10-15
+ */
+static inline rsRetVal
+thrdTerminateNonCancel(thrdInfo_t *pThis)
+{
+	struct timespec tTimeout;
+	int ret;
+	DEFiRet;
+	assert(pThis != NULL);
+
+	DBGPRINTF("request term via SIGTTIN for input thread '%s' 0x%x\n",
+		  pThis->name, (unsigned) pThis->thrdID);
+	pThis->bShallStop = RSTRUE;
+	do {
+		d_pthread_mutex_lock(&pThis->mutThrd);
+		pthread_kill(pThis->thrdID, SIGTTIN);
+		timeoutComp(&tTimeout, 1000); /* a fixed 1sec timeout */
+		ret = d_pthread_cond_timedwait(&pThis->condThrdTerm, &pThis->mutThrd, &tTimeout);
+		d_pthread_mutex_unlock(&pThis->mutThrd);
+		if(Debug) {
+			if(ret == ETIMEDOUT) {
+				dbgprintf("input thread term: timeout expired waiting on thread %s termination - canceling\n", pThis->name);
+				pthread_cancel(pThis->thrdID);
+				pThis->bIsActive = 0;
+			} else if(ret == 0) {
+				dbgprintf("input thread term: thread %s returned normally and is terminated\n", pThis->name);
+			} else {
+				char errStr[1024];
+				int err = errno;
+				rs_strerror_r(err, errStr, sizeof(errStr));
+				dbgprintf("input thread term: cond_wait returned with error %d: %s\n",
+					  err, errStr);
+			}
+		}
+	} while(pThis->bIsActive);
+	DBGPRINTF("non-cancel input thread termination succeeded for thread %s 0x%x\n",
+		  pThis->name, (unsigned) pThis->thrdID);
+
+	RETiRet;
+}
+
+
+/* terminate a thread gracefully.
+ */
+rsRetVal thrdTerminate(thrdInfo_t *pThis)
+{
+	DEFiRet;
+	assert(pThis != NULL);
+	
+	if(pThis->bNeedsCancel) {
+		DBGPRINTF("request term via canceling for input thread 0x%x\n", (unsigned) pThis->thrdID);
+		pthread_cancel(pThis->thrdID);
+		pThis->bIsActive = 0;
+	} else {
+		thrdTerminateNonCancel(pThis);
+	}
+	pthread_join(pThis->thrdID, NULL); /* wait for input thread to complete */
+
+	/* call cleanup function, if any */
+	if(pThis->pAfterRun != NULL)
+		pThis->pAfterRun(pThis);
+	
+	RETiRet;
+}
+
+
+/* terminate all known threads gracefully.
+ */
+rsRetVal thrdTerminateAll(void)
+{
+	DEFiRet;
+	llDestroy(&llThrds);
+	RETiRet;
+}
+
+
+/* This is an internal wrapper around the user thread function. Its
+ * purpose is to handle all the necessary housekeeping stuff so that the
+ * user function needs not to be aware of the threading calls. The user
+ * function call has just "normal", non-threading semantics.
+ * rgerhards, 2007-12-17
+ */
+static void* thrdStarter(void *arg)
+{
+	DEFiRet;
+	thrdInfo_t *pThis = (thrdInfo_t*) arg;
+#	if HAVE_PRCTL && defined PR_SET_NAME
+	uchar thrdName[32] = "in:";
+#	endif
+
+	assert(pThis != NULL);
+	assert(pThis->pUsrThrdMain != NULL);
+
+#	if HAVE_PRCTL && defined PR_SET_NAME
+	ustrncpy(thrdName+3, pThis->name, 20);
+	dbgOutputTID((char*)thrdName);
+
+	/* set thread name - we ignore if the call fails, has no harsh consequences... */
+	if(prctl(PR_SET_NAME, thrdName, 0, 0, 0) != 0) {
+		DBGPRINTF("prctl failed, not setting thread name for '%s'\n", pThis->name);
+	} else {
+		DBGPRINTF("set thread name to '%s'\n", thrdName);
+	}
+#	endif
+
+	/* block all signals */
+	sigset_t sigSet;
+	sigfillset(&sigSet);
+	pthread_sigmask(SIG_BLOCK, &sigSet, NULL);
+
+	/* but ignore SIGTTN, which we (ab)use to signal the thread to shutdown -- rgerhards, 2009-07-20 */
+	sigemptyset(&sigSet);
+	sigaddset(&sigSet, SIGTTIN);
+	pthread_sigmask(SIG_UNBLOCK, &sigSet, NULL);
+
+	/* setup complete, we are now ready to execute the user code. We will not
+	 * regain control until the user code is finished, in which case we terminate
+	 * the thread.
+	 */
+	iRet = pThis->pUsrThrdMain(pThis);
+
+	dbgprintf("thrdStarter: usrThrdMain %s - 0x%lx returned with iRet %d, exiting now.\n",
+		  pThis->name, (unsigned long) pThis->thrdID, iRet);
+
+	/* signal master control that we exit (we do the mutex lock mostly to 
+	 * keep the thread debugger happer, it would not really be necessary with
+	 * the logic we employ...)
+	 */
+	d_pthread_mutex_lock(&pThis->mutThrd);
+	pThis->bIsActive = 0;
+	pthread_cond_signal(&pThis->condThrdTerm);
+	d_pthread_mutex_unlock(&pThis->mutThrd);
+
+	ENDfunc
+	pthread_exit(0);
+}
+
+/* Start a new thread and add it to the list of currently
+ * executing threads. It is added at the end of the list.
+ * rgerhards, 2007-12-14
+ */
+rsRetVal thrdCreate(rsRetVal (*thrdMain)(thrdInfo_t*), rsRetVal(*afterRun)(thrdInfo_t *), sbool bNeedsCancel, uchar *name)
+{
+	DEFiRet;
+	thrdInfo_t *pThis;
+
+	assert(thrdMain != NULL);
+
+	CHKiRet(thrdConstruct(&pThis));
+	pThis->bIsActive = 1;
+	pThis->pUsrThrdMain = thrdMain;
+	pThis->pAfterRun = afterRun;
+	pThis->bNeedsCancel = bNeedsCancel;
+	pThis->name = ustrdup(name);
+	pthread_create(&pThis->thrdID,
+#ifdef HAVE_PTHREAD_SETSCHEDPARAM
+			   &default_thread_attr,
+#else
+			   NULL,
+#endif
+			   thrdStarter, pThis);
+	CHKiRet(llAppend(&llThrds, NULL, pThis));
+
+finalize_it:
+	RETiRet;
+}
+
+
+/* initialize the thread-support subsystem
+ * must be called once at the start of the program
+ */
+rsRetVal thrdInit(void)
+{
+	DEFiRet;
+	iRet = llInit(&llThrds, thrdDestruct, NULL, NULL);
+	RETiRet;
+}
+
+
+/* de-initialize the thread subsystem
+ * must be called once at the end of the program
+ */
+rsRetVal thrdExit(void)
+{
+	DEFiRet;
+	iRet = llDestroy(&llThrds);
+	RETiRet;
+}
+
+
+/* vi:set ai:
+ */