diff options
Diffstat (limited to 'syslogd.c')
| -rw-r--r-- | syslogd.c | 57 |
1 files changed, 42 insertions, 15 deletions
@@ -552,7 +552,7 @@ static void debug_switch(); static rsRetVal cfline(uchar *line, selector_t **pfCurr); static int decode(uchar *name, struct code *codetab); static void sighup_handler(); -static void die(int sig); +//static void die(int sig); static void freeSelectors(void); static rsRetVal processConfFile(uchar *pConfFile); static rsRetVal selectorAddList(selector_t *f); @@ -2594,8 +2594,26 @@ die(int sig) { char buf[256]; + dbgprintf("exiting on signal %d\n", sig); + + /* IMPORTANT: we should close the inputs first, and THEN send our termination + * message. If we do it the other way around, logmsgInternal() may block on + * a full queue and the inputs still fill up that queue. Depending on the + * scheduling order, we may end up with logmsgInternal being held for a quite + * long time. When the inputs are terminated first, that should not happen + * because the queue is drained in parallel. The situation could only become + * an issue with extremely long running actions in a queue full environment. + * However, such actions are at least considered poorly written, if not + * outright wrong. So we do not care about this very remote problem. + * rgerhards, 2008-01-11 + */ + + /* close the inputs */ + dbgprintf("Terminating input threads...\n"); + thrdTerminateAll(); /* TODO: inputs only, please */ + + /* and THEN send the termination log message (see long comment above) */ if (sig) { - dbgprintf("exiting on signal %d\n", sig); (void) snprintf(buf, sizeof(buf) / sizeof(char), " [origin software=\"rsyslogd\" " "swVersion=\"" VERSION \ "\" x-pid=\"%d\"]" " exiting on signal %d.", @@ -2604,16 +2622,14 @@ die(int sig) logmsgInternal(LOG_SYSLOG|LOG_INFO, buf, ADDDATE); } - /* close the inputs */ - dbgprintf("Terminating input threads...\n"); - thrdTerminateAll(); /* TODO: inputs only, please */ - - /* drain queue and stop worker thread */ + /* drain queue (if configured so) and stop main queue worker thread pool */ dbgprintf("Terminating main queue...\n"); queueDestruct(pMsgQueue); pMsgQueue = NULL; - /* Free ressources and close connections */ + /* Free ressources and close connections. This includes flushing any remaining + * repeated msgs. + */ dbgprintf("Terminating outputs...\n"); freeSelectors(); @@ -2650,7 +2666,6 @@ die(int sig) */ unregCfSysLineHdlrs(); - /* clean up auxiliary data */ if(pModDir != NULL) free(pModDir); @@ -3270,7 +3285,7 @@ init(void) char bufStartUpMsg[512]; struct sigaction sigAct; - thrdTerminateAll(); /* stop all running threads - TODO: reconsider location! */ + thrdTerminateAll(); /* stop all running input threads - TODO: reconsider location! */ /* initialize some static variables */ pDfltHostnameCmp = NULL; @@ -3366,7 +3381,6 @@ init(void) fprintf(stderr, "fatal error %d: could not create message queue - rsyslogd can not run!\n", iRet); exit(1); } -dbgprintf("queue 1 \n"); /* ... set some properties ... */ # define setQPROP(func, directive, data) \ CHKiRet_Hdlr(func(pMsgQueue, data)) { \ @@ -3378,21 +3392,18 @@ dbgprintf("queue 1 \n"); } setQPROP(queueSetMaxFileSize, "$MainMsgQueueFileSize", iMainMsgQueMaxFileSize); -dbgprintf("queue 2 \n"); setQPROPstr(queueSetFilePrefix, "$MainMsgQueueFileName", (pszMainMsgQFName == NULL ? (uchar*) "mainq" : pszMainMsgQFName)); # undef setQPROP # undef setQPROPstr -dbgprintf("try start queue \n"); /* ... and finally start the queue! */ CHKiRet_Hdlr(queueStart(pMsgQueue)) { /* no queue is fatal, we need to give up in that case... */ fprintf(stderr, "fatal error %d: could not start message queue - rsyslogd can not run!\n", iRet); exit(1); } -dbgprintf("queue running\n"); Initialized = 1; bHaveMainQueue = (MainMsgQueType == QUEUETYPE_DIRECT) ? 0 : 1; @@ -3405,7 +3416,6 @@ dbgprintf("queue running\n"); */ startInputModules(); -dbgprintf("inputs running\n"); if(Debug) { dbgPrintInitInfo(); } @@ -4427,12 +4437,29 @@ mainloop(void) tvSelectTimeout.tv_sec = TIMERINTVL; tvSelectTimeout.tv_usec = 0; select(1, NULL, NULL, NULL, &tvSelectTimeout); + if(bFinished) + break; /* exit as quickly as possible - see long comment below */ /* If we received a HUP signal, we call doFlushRptdMsgs() a bit early. This * doesn't matter, because doFlushRptdMsgs() checks timestamps. What may happen, * however, is that the too-early call may lead to a bit too-late output * of "last message repeated n times" messages. But that is quite acceptable. * rgerhards, 2007-12-21 + * ... and just to explain, we flush here because that is exactly what the mainloop + * shall do - provide a periodic interval in which not-yet-flushed messages will + * be flushed. Be careful, there is a potential race condition: doFlushRptdMsgs() + * needs to aquire a lock on the action objects. If, however, long-running consumers + * cause the main queue worker threads to lock them for a long time, we may receive + * a starvation condition, resulting in the mainloop being held on lock for an extended + * period of time. That, in turn, could lead to unresponsiveness to termination + * requests. It is especially important that the bFinished flag is checked before + * doFlushRptdMsgs() is called (I know because I ran into that situation). I am + * not yet sure if the remaining probability window of a termination-related + * problem is large enough to justify changing the code - I would consider it + * extremely unlikely that the problem ever occurs in practice. Fixing it would + * require not only a lot of effort but would cost considerable performance. So + * for the time being, I think the remaining risk can be accepted. + * rgerhards, 2008-01-10 */ doFlushRptdMsgs(); |