refactored imklog linux driver, now combined with BSD driver

The Linux driver no longer supports outdated kernel symbol resolution,
which was disabled by default for very long. Also overall cleanup,
resulting in much smaller code. Linux and BSD are now covered by a
single small driver.

1 files changed, 165 insertions, 79 deletions

diff --git a/plugins/imklog/bsd.c b/plugins/imklog/bsd.c
index 930bbd11..eaf8e5ca 100644
--- a/plugins/imklog/bsd.c
+++ b/plugins/imklog/bsd.c
@@ -1,69 +1,30 @@
-/* klog for BSD, based on the FreeBSD syslogd implementation.
+/* combined imklog driver for BSD and Linux
  *
  * This contains OS-specific functionality to read the BSD
- * kernel log. For a general overview, see head comment in
- * imklog.c.
+ * or Linux kernel log. For a general overview, see head comment in
+ * imklog.c. This started out as the BSD-specific drivers, but it
+ * turned out that on modern Linux the implementation details
+ * are very small, and so we use a single driver for both OS's with
+ * a little help of conditional compilation.
  *
- * Copyright (C) 2008 by Rainer Gerhards for the modifications of
- * the original FreeBSD sources.
- *
- * I would like to express my gratitude to those folks which
- * layed an important foundation for rsyslog to build on.
+ * Copyright 2008-2012 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.
- *
- * This file is based on earlier work included in the FreeBSD sources. We
- * integrated it into the rsyslog project. The copyright below applies, and
- * I also reproduce the original license under which we aquired the code:
- *
- * Copyright (c) 1983, 1988, 1993, 1994
- *	The Regents of the University of California.  All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 4. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * If you would like to use the code under the BSD license, you should
- * aquire your own copy of BSD's syslogd, from which we have taken it. The
- * code in this file is modified and may only be used under the terms of
- * the GPLv3+ as specified above.
+ * 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.
  */
-
 #ifdef HAVE_CONFIG_H
 #	include "config.h"
 #endif
@@ -72,18 +33,124 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <string.h>
+#include <ctype.h>
+#ifdef	OS_LINUX
+#	include <sys/klog.h>
+#endif
 
 #include "rsyslog.h"
-#include "imklog.h"
+#include "srUtils.h"
 #include "debug.h"
+#include "imklog.h"
 
 /* globals */
-static int	fklog = -1;	/* /dev/klog */
+static int	fklog = -1;	/* kernel log fd */
 
 #ifndef _PATH_KLOG
-#	define _PATH_KLOG "/dev/klog"
+#	ifdef OS_LINUX
+#	  define _PATH_KLOG "/proc/kmsg"
+#	else
+#	  define _PATH_KLOG "/dev/klog"
+#	endif
 #endif
 
+
+#ifdef OS_LINUX
+/* submit a message to imklog Syslog() API. In this function, we check if 
+ * a kernel timestamp is present and, if so, extract and strip it.
+ * Note: this is an extra processing step. We should revisit the whole
+ * idea in v6 and remove all that old stuff that we do not longer need
+ * (like symbol resolution). <-- TODO 
+ * Note that this is heavily Linux specific and thus is not compiled or
+ * used for BSD.
+ * Special thanks to Lennart Poettering for suggesting on how to convert
+ * the kernel timestamp to a realtime timestamp. This method depends on 
+ * the fact the the kernel timestamp is written using the monotonic clock.
+ * Shall that change (very unlikely), this code must be changed as well. Note
+ * that due to the way we generate the delta, we are unable to write the
+ * absolutely correct timestamp (system call overhead of the clock calls
+ * prevents us from doing so). However, the difference is very minor.
+ * rgerhards, 2011-06-24
+ */
+static void
+submitSyslog(int pri, uchar *buf)
+{
+	long secs;
+	long nsecs;
+	long secOffs;
+	long nsecOffs;
+	unsigned i;
+	unsigned bufsize;
+	struct timespec monotonic, realtime;
+	struct timeval tv;
+	struct timeval *tp = NULL;
+
+	if(buf[3] != '[')
+		goto done;
+	DBGPRINTF("imklog: kernel timestamp detected, extracting it\n");
+
+	/* we now try to parse the timestamp. iff it parses, we assume
+	 * it is a timestamp. Otherwise we know for sure it is no ts ;)
+	 */
+	i = 4; /* first digit after '[' */
+	secs = 0;
+	while(buf[i] && isdigit(buf[i])) {
+		secs = secs * 10 + buf[i] - '0';
+		++i;
+	}
+	if(buf[i] != '.') {
+		DBGPRINTF("no dot --> no kernel timestamp\n");
+		goto done; /* no TS! */
+	}
+	
+	++i; /* skip dot */
+	nsecs = 0;
+	while(buf[i] && isdigit(buf[i])) {
+		nsecs = nsecs * 10 + buf[i] - '0';
+		++i;
+	}
+	if(buf[i] != ']') {
+		DBGPRINTF("no trailing ']' --> no kernel timestamp\n");
+		goto done; /* no TS! */
+	}
+	++i; /* skip ']' */
+
+	/* we have a timestamp */
+	DBGPRINTF("kernel timestamp is %ld %ld\n", secs, nsecs);
+	bufsize= strlen((char*)buf);
+	memcpy(buf+3, buf+i, bufsize - i + 1);
+
+	clock_gettime(CLOCK_MONOTONIC, &monotonic);
+	clock_gettime(CLOCK_REALTIME, &realtime);
+	secOffs = realtime.tv_sec - monotonic.tv_sec;
+	nsecOffs = realtime.tv_nsec - monotonic.tv_nsec;
+	if(nsecOffs < 0) {
+		secOffs--;
+		nsecOffs += 1000000000l;
+	}
+	
+	nsecs +=nsecOffs;
+	if(nsecs > 999999999l) {
+		secs++;
+		nsecs -= 1000000000l;
+	}
+	secs += secOffs;
+	tv.tv_sec = secs;
+	tv.tv_usec = nsecs / 1000;
+	tp = &tv;
+
+done:
+	Syslog(pri, buf, tp);
+}
+#else	/* now comes the BSD "code" (just a shim) */
+static void
+submitSyslog(int pri, uchar *buf)
+{
+	Syslog(pri, buf, NULL);
+}
+#endif	/* #ifdef LINUX */
+
+
 static uchar *GetPath(void)
 {
 	return pszPath ? pszPath : (uchar*) _PATH_KLOG;
@@ -95,23 +162,36 @@ static uchar *GetPath(void)
 rsRetVal
 klogWillRun(void)
 {
+	char errmsg[2048];
+	int r;
 	DEFiRet;
 
 	fklog = open((char*)GetPath(), O_RDONLY, 0);
 	if (fklog < 0) {
-		dbgprintf("can't open %s (%d)\n", GetPath(), errno);
-		iRet = RS_RET_ERR; // TODO: better error code
+		imklogLogIntMsg(RS_RET_ERR_OPEN_KLOG, "imklog: cannot open kernel log(%s): %s.",
+			GetPath(), rs_strerror_r(errno, errmsg, sizeof(errmsg)));
+		ABORT_FINALIZE(RS_RET_ERR_OPEN_KLOG);
+	}
+
+#	ifdef OS_LINUX
+	/* Set level of kernel console messaging.. */
+	if(console_log_level != -1) {
+		r = klogctl(8, NULL, console_log_level);
+		if(r != 0) {
+			imklogLogIntMsg(LOG_WARNING, "imklog: cannot set console log level: %s",
+				rs_strerror_r(errno, errmsg, sizeof(errmsg)));
+			/* make sure we do not try to re-set! */
+			console_log_level = -1;
+		}
 	}
+#	endif	/* #ifdef OS_LINUX */
 
+finalize_it:
 	RETiRet;
 }
 
 
-/* Read /dev/klog while data are available, split into lines.
- * Contrary to standard BSD syslogd, we do a blocking read. We can
- * afford this as imklog is running on its own threads. So if we have
- * a single file, it really doesn't matter if we wait inside a 1-file
- * select or the read() directly.
+/* Read kernel log while data are available, split into lines.
  */
 static void
 readklog(void)
@@ -119,13 +199,14 @@ readklog(void)
 	char *p, *q;
 	int len, i;
 	int iMaxLine;
-	uchar bufRcv[4096+1];
+	uchar bufRcv[128*1024+1];
+	char errmsg[2048];
 	uchar *pRcv = NULL; /* receive buffer */
 
 	iMaxLine = klog_getMaxLine();
 
-	/* we optimize performance: if iMaxLine is below 4K (which it is in almost all
-	 * cases, we use a fixed buffer on the stack. Only if it is higher, heap memory
+	/* we optimize performance: if iMaxLine is below our fixed size buffer (which
+	 * usually is sufficiently large), we use this buffer. if it is higher, heap memory
 	 * is used. We could use alloca() to achive a similar aspect, but there are so
 	 * many issues with alloca() that I do not want to take that route.
 	 * rgerhards, 2008-09-02
@@ -139,15 +220,15 @@ readklog(void)
 
 	len = 0;
 	for (;;) {
-		dbgprintf("----------imklog(BSD) waiting for kernel log line\n");
+		dbgprintf("imklog(BSD/Linux) waiting for kernel log line\n");
 		i = read(fklog, pRcv + len, iMaxLine - len);
 		if (i > 0) {
 			pRcv[i + len] = '\0';
 		} else {
 			if (i < 0 && errno != EINTR && errno != EAGAIN) {
 				imklogLogIntMsg(LOG_ERR,
-				       "imklog error %d reading kernel log - shutting down imklog",
-				       errno);
+				       "imklog: error reading kernel log - shutting down: %s",
+					rs_strerror_r(errno, errmsg, sizeof(errmsg)));
 				fklog = -1;
 			}
 			break;
@@ -155,18 +236,18 @@ readklog(void)
 
 		for (p = (char*)pRcv; (q = strchr(p, '\n')) != NULL; p = q + 1) {
 			*q = '\0';
-			Syslog(LOG_INFO, (uchar*) p, NULL);
+			submitSyslog(LOG_INFO, (uchar*) p);
 		}
 		len = strlen(p);
 		if (len >= iMaxLine - 1) {
-			Syslog(LOG_INFO, (uchar*)p, NULL);
+			submitSyslog(LOG_INFO, (uchar*)p);
 			len = 0;
 		}
-		if (len > 0)
+		if(len > 0)
 			memmove(pRcv, p, len + 1);
 	}
 	if (len > 0)
-		Syslog(LOG_INFO, pRcv, NULL);
+		submitSyslog(LOG_INFO, pRcv);
 
 	if(pRcv != NULL && (size_t) iMaxLine >= sizeof(bufRcv) - 1)
 		free(pRcv);
@@ -181,6 +262,11 @@ rsRetVal klogAfterRun(void)
         DEFiRet;
 	if(fklog != -1)
 		close(fklog);
+#	ifdef OS_LINUX
+	/* Turn on logging of messages to console, but only if a log level was speficied */
+	if(console_log_level != -1)
+		klogctl(7, NULL, 0);
+#	endif
         RETiRet;
 }