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authorRainer Gerhards <rgerhards@adiscon.com>2005-10-13 16:11:54 +0000
committerRainer Gerhards <rgerhards@adiscon.com>2005-10-13 16:11:54 +0000
commit28ff893ce64e2a46b62fb517c268ed1785c009c2 (patch)
tree13b6f0beef0e468875418f618d05d28b6ae92bf4 /syslogd.c
parent4ae1f8a765772d21446ad7f8158fd9d882d06c40 (diff)
downloadrsyslog-28ff893ce64e2a46b62fb517c268ed1785c009c2.tar.gz
rsyslog-28ff893ce64e2a46b62fb517c268ed1785c009c2.tar.xz
rsyslog-28ff893ce64e2a46b62fb517c268ed1785c009c2.zip
some restructuring, mostly preparation for an eventual move to a
dual-threading model
Diffstat (limited to 'syslogd.c')
-rw-r--r--syslogd.c301
1 files changed, 166 insertions, 135 deletions
diff --git a/syslogd.c b/syslogd.c
index f3ac35c1..f5f63880 100644
--- a/syslogd.c
+++ b/syslogd.c
@@ -731,7 +731,7 @@ int main(int argc, char **argv);
char **crunch_list(char *list);
static int usage(void);
void untty(void);
-void printchopped(char *hname, char *msg, int len, int fd, int iSourceType);
+static void printchopped(char *hname, char *msg, int len, int fd, int iSourceType);
void printline(char *hname, char *msg, int iSource);
void printsys(char *msg);
void logmsg(int pri, struct msg*, int flags);
@@ -3279,7 +3279,7 @@ void untty()
* unix domain sockets but contain the hostname). rgerhards, 2005-10-06
*/
-void printchopped(char *hname, char *msg, int len, int fd, int bParseHost)
+static void printchopped(char *hname, char *msg, int len, int fd, int bParseHost)
{
auto int ptlngth;
@@ -3584,6 +3584,136 @@ int shouldProcessThisMessage(struct filed *f, struct msg *pMsg)
}
+/* Process (consume) a received message. Calls the actions configured.
+ * Can some time later run in its own thread. To aid this, the calling
+ * parameters should be reduced to just pMsg.
+ * See comment dated 2005-10-13 in logmsg() on multithreading.
+ * rgerhards, 2005-10-13
+ */
+static void processMsg(struct msg *pMsg, int flags)
+{
+ register struct filed *f;
+
+ assert(pMsg != NULL);
+
+ /* log the message to the particular outputs */
+ if (!Initialized) {
+ /* If we reach this point, the daemon initialization FAILED. That is,
+ * syslogd is NOT actually running. So what we do here is just
+ * initialize a pointer to the system console and then output
+ * the message to the it. So at least we have a little
+ * chance that messages show up somewhere.
+ * rgerhards 2004-11-09
+ */
+ f = &consfile;
+ f->f_file = open(ctty, O_WRONLY|O_NOCTTY);
+
+ if (f->f_file >= 0) {
+ untty();
+ f->f_pMsg = MsgAddRef(pMsg); /* is expected here... */
+ fprintlog(f, flags);
+ MsgDestruct(pMsg);
+ (void) close(f->f_file);
+ f->f_file = -1;
+ }
+
+ /* now log to a second emergency log... 2005-06-21 rgerhards */
+ /* TODO: make this configurable, eventually via the command line */
+ if(ttyname(0) != NULL) {
+ memset(&emergfile, 0, sizeof(emergfile));
+ f = &emergfile;
+ emergfile.f_type = F_TTY;
+ (void) strcpy(emergfile.f_un.f_fname, ttyname(0));
+ cflineSetTemplateAndIOV(&emergfile, " TradFmt");
+ f->f_file = open(ttyname(0), O_WRONLY|O_NOCTTY);
+
+ if (f->f_file >= 0) {
+ untty();
+ f->f_pMsg = MsgAddRef(pMsg); /* is expected here... */
+ fprintlog(f, flags);
+ MsgDestruct(pMsg);
+ (void) close(f->f_file);
+ f->f_file = -1;
+ }
+ }
+ return; /* we are done with emergency loging */
+ }
+
+ for (f = Files; f; f = f->f_next) {
+ /* first, we need to check if this is a disabled (F_UNUSED)
+ * entry. If so, we must not further process it, as the data
+ * structure probably contains invalid pointers and other
+ * such mess.
+ * rgerhards 2005-09-26
+ */
+ if(f->f_type == F_UNUSED)
+ continue; /* on to next */
+
+ /* This is actually the "filter logic". Looks like we need
+ * to improve it a little for complex selector line conditions. We
+ * won't do that for now, but at least we now know where
+ * to look at.
+ * 2005-09-09 rgerhards
+ * ok, we are now ready to move to something more advanced. Because
+ * of this, I am moving the actual decision code to outside this function.
+ * 2005-09-19 rgerhards
+ */
+ if(!shouldProcessThisMessage(f, pMsg)) {
+ continue;
+ }
+
+ /* We now need to check a special case - F_DISCARD. If that
+ * action is specified in the selector line, no futher processing
+ * must be done. Thus, we stop the for-loop.
+ * 2005-09-09 rgerhards
+ */
+ if(f->f_type == F_DISCARD) {
+ dprintf("Discarding message based on selector config\n");
+ break; /* that's it for this message ;) */
+ }
+
+ if (f->f_type == F_CONSOLE && (flags & IGN_CONS))
+ continue;
+
+ /* don't output marks to recently written files */
+ if ((flags & MARK) && (now - f->f_time) < MarkInterval / 2)
+ continue;
+
+ /*
+ * suppress duplicate lines to this file
+ */
+ if ((flags & MARK) == 0 && getMSGLen(pMsg) == getMSGLen(f->f_pMsg) &&
+ !strcmp(getMSG(pMsg), getMSG(f->f_pMsg)) &&
+ !strcmp(getHOSTNAME(pMsg), getHOSTNAME(f->f_pMsg))) {
+ f->f_prevcount++;
+ dprintf("msg repeated %d times, %ld sec of %d.\n",
+ f->f_prevcount, now - f->f_time,
+ repeatinterval[f->f_repeatcount]);
+ /*
+ * If domark would have logged this by now,
+ * flush it now (so we don't hold isolated messages),
+ * but back off so we'll flush less often
+ * in the future.
+ */
+ if (now > REPEATTIME(f)) {
+ fprintlog(f, flags);
+ BACKOFF(f);
+ }
+ } else {
+ /* new line, save it */
+ /* first check if we have a previous message stored
+ * if so, discard that first
+ */
+ if(f->f_pMsg != NULL)
+ MsgDestruct(f->f_pMsg);
+ f->f_pMsg = MsgAddRef(pMsg);
+ /* call the output driver */
+ fprintlog(f, flags);
+ }
+ }
+}
+
+
/*
* Log a message to the appropriate log files, users, etc. based on
* the priority.
@@ -3603,16 +3733,10 @@ int shouldProcessThisMessage(struct filed *f, struct msg *pMsg)
* potential for misinterpretation, which we simply can not solve under the
* circumstances given.
*/
-
void logmsg(int pri, struct msg *pMsg, int flags)
{
- register struct filed *f;
-
/* allocate next entry and add it */
- int fac, prilev;
- int msglen;
char *msg;
- char *from;
char *p2parse;
char *pBuf;
char *pWork;
@@ -3623,25 +3747,16 @@ void logmsg(int pri, struct msg *pMsg, int flags)
assert(pMsg != NULL);
assert(pMsg->pszUxTradMsg != NULL);
msg = pMsg->pszUxTradMsg;
- from = pMsg->pszHOSTNAME;
- dprintf("logmsg: %s, flags %x, from %s, msg %s\n", textpri(pri), flags, from, msg);
+ dprintf("logmsg: %s, flags %x, from %s, msg %s\n", textpri(pri), flags, pMsg->pszHOSTNAME, msg);
#ifndef SYSV
omask = sigblock(sigmask(SIGHUP)|sigmask(SIGALRM));
#endif
- /* extract facility and priority level */
- if (flags & MARK)
- fac = LOG_NFACILITIES;
- else
- fac = LOG_FAC(pri);
- prilev = LOG_PRI(pri);
-
p2parse = msg; /* our "message" begins here */
/*
* Check to see if msg contains a timestamp
*/
- msglen = pMsg->iLenMSG;
if(srSLMGParseTIMESTAMP3164(&(pMsg->tTIMESTAMP), msg) == TRUE)
p2parse += 16;
else {
@@ -3727,124 +3842,40 @@ void logmsg(int pri, struct msg *pMsg, int flags)
/* ---------------------- END PARSING ---------------- */
- /* log the message to the particular outputs */
- if (!Initialized) {
- /* If we reach this point, the daemon initialization FAILED. That is,
- * syslogd is NOT actually running. So what we do here is just
- * initialize a pointer to the system console and then output
- * the message to the it. So at least we have a little
- * chance that messages show up somewhere.
- * rgerhards 2004-11-09
- */
- f = &consfile;
- f->f_file = open(ctty, O_WRONLY|O_NOCTTY);
-
- if (f->f_file >= 0) {
- untty();
- f->f_pMsg = MsgAddRef(pMsg); /* is expected here... */
- fprintlog(f, flags);
- MsgDestruct(pMsg);
- (void) close(f->f_file);
- f->f_file = -1;
- }
-
- /* now log to a second emergency log... 2005-06-21 rgerhards */
- /* TODO: make this configurable, eventually via the command line */
- if(ttyname(0) != NULL) {
- memset(&emergfile, 0, sizeof(emergfile));
- f = &emergfile;
- emergfile.f_type = F_TTY;
- (void) strcpy(emergfile.f_un.f_fname, ttyname(0));
- cflineSetTemplateAndIOV(&emergfile, " TradFmt");
- f->f_file = open(ttyname(0), O_WRONLY|O_NOCTTY);
-
- if (f->f_file >= 0) {
- untty();
- f->f_pMsg = MsgAddRef(pMsg); /* is expected here... */
- fprintlog(f, flags);
- MsgDestruct(pMsg);
- (void) close(f->f_file);
- f->f_file = -1;
- }
- }
-#ifndef SYSV
- (void) sigsetmask(omask);
-#endif
- return; /* we are done with emergency loging */
- }
-
- for (f = Files; f; f = f->f_next) {
- /* first, we need to check if this is a disabled (F_UNUSED)
- * entry. If so, we must not further process it, as the data
- * structure probably contains invalid pointers and other
- * such mess.
- * rgerhards 2005-09-26
- */
- if(f->f_type == F_UNUSED)
- continue; /* on to next */
-
- /* This is actually the "filter logic". Looks like we need
- * to improve it a little for complex selector line conditions. We
- * won't do that for now, but at least we now know where
- * to look at.
- * 2005-09-09 rgerhards
- * ok, we are now ready to move to something more advanced. Because
- * of this, I am moving the actual decision code to outside this function.
- * 2005-09-19 rgerhards
- */
- if(!shouldProcessThisMessage(f, pMsg)) {
- continue;
- }
-
- /* We now need to check a special case - F_DISCARD. If that
- * action is specified in the selector line, no futher processing
- * must be done. Thus, we stop the for-loop.
- * 2005-09-09 rgerhards
- */
- if(f->f_type == F_DISCARD) {
- dprintf("Discarding message based on selector config\n");
- break; /* that's it for this message ;) */
- }
-
- if (f->f_type == F_CONSOLE && (flags & IGN_CONS))
- continue;
-
- /* don't output marks to recently written files */
- if ((flags & MARK) && (now - f->f_time) < MarkInterval / 2)
- continue;
+ /* rgerhards, 2005-10-13: if we consider going multi-threaded, this
+ * is probably the best point to split between a producer and a consumer
+ * thread. In general, with the first multi-threaded approach, we should
+ * NOT try to do more than have a single producer and consumer, at least
+ * if both are from the current code base. The issue is that this code
+ * was definitely not written with reentrancy in mind and uses a lot of
+ * global variables. So it is very dangerous to simply go ahead and multi
+ * thread it. However, I think there is a clear distinction between
+ * producer (where data is received) and consumer (where the actions are).
+ * It should be fairly safe to create a single thread for each and run them
+ * concurrently, thightly coupled via an in-memory queue. Even with this
+ * limited multithraeding, benefits are immediate: the lengthy actions
+ * (database writes!) are de-coupled from the receivers, what should result
+ * in less likely message loss (loss due to receiver overrun). It also allows
+ * us to utilize 2-cpu systems, which will soon be common given the current
+ * advances in multicore CPU hardware. So this is well worth trying.
+ * Another plus of this two-thread-approach would be that it can easily be configured,
+ * so if there are compatibility issues with the threading libs, we could simply
+ * disable it (as a makefile feature).
+ * There is one important thing to keep in mind when doing this basic
+ * multithreading. The syslog/tcp message forwarder manipulates a structutre
+ * that is used by the main thread, which actually sends the data. This
+ * structure must be guarded by a mutex, else we will have race conditions and
+ * some very bad things could happen.
+ *
+ * Additional consumer threads might be added relatively easy for new receivers,
+ * e.g. if we decide to move RFC 3195 via liblogging natively into rsyslogd.
+ *
+ * To aid this functionality, I am moving the rest of the code (the actual
+ * consumer) to its own method, now called "processMsg()".
+ */
+
+ processMsg(pMsg, flags);
- /*
- * suppress duplicate lines to this file
- */
- if ((flags & MARK) == 0 && msglen == getMSGLen(f->f_pMsg) &&
- !strcmp(msg, getMSG(f->f_pMsg)) &&
- !strcmp(from, getHOSTNAME(f->f_pMsg))) {
- f->f_prevcount++;
- dprintf("msg repeated %d times, %ld sec of %d.\n",
- f->f_prevcount, now - f->f_time,
- repeatinterval[f->f_repeatcount]);
- /*
- * If domark would have logged this by now,
- * flush it now (so we don't hold isolated messages),
- * but back off so we'll flush less often
- * in the future.
- */
- if (now > REPEATTIME(f)) {
- fprintlog(f, flags);
- BACKOFF(f);
- }
- } else {
- /* new line, save it */
- /* first check if we have a previous message stored
- * if so, discard that first
- */
- if(f->f_pMsg != NULL)
- MsgDestruct(f->f_pMsg);
- f->f_pMsg = MsgAddRef(pMsg);
- /* call the output driver */
- fprintlog(f, flags);
- }
- }
#ifndef SYSV
(void) sigsetmask(omask);
#endif