re-wrote syslog.c from scratch to solve a license compatibility issue,

    provide some bug fixes and performance enhancemnts. Also required
    changes to klogd.c to support the new interface.

1 files changed, 104 insertions, 218 deletions

diff --git a/syslog.c b/syslog.c
index 59822220..889b0057 100644
--- a/syslog.c
+++ b/syslog.c
@@ -1,252 +1,138 @@
-/*
- * Copyright (c) 1983, 1988 Regents of the University of California.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms are permitted provided
- * that: (1) source distributions retain this entire copyright notice and
- * comment, and (2) distributions including binaries display the following
- * acknowledgement:  ``This product includes software developed by the
- * University of California, Berkeley and its contributors'' in the
- * documentation or other materials provided with the distribution and in
- * all advertising materials mentioning features or use of this software.
- * 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
- * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
- */
-
-/*
- * SYSLOG -- print message on log file
- *
- * This routine looks a lot like printf, except that it outputs to the
- * log file instead of the standard output.  Also:
- *	adds a timestamp,
- *	prints the module name in front of the message,
- *	has some other formatting types (or will sometime),
- *	adds a newline on the end of the message.
+/* logger.c
+ * Helper routines for klogd. It replaces the regular glibc syslog()
+ * call. The reason is that the glibc version does not support
+ * logging with the kernel facility. This file is a re-implementation
+ * of the functions with only the functionality required for klogd.
+ * So it can NOT be used as a general-purpose replacment.
+ * Thanks to being special, this version is deemed to be considerable
+ * faster than its glibc counterpart.
+ * To avoid confusion, the syslog() replacement is named writeSyslog().
+ * all other functions are just helpers to it.
+ * RGerhards, 2007-06-14
  *
- * The output of this routine is intended to be read by syslogd(8).
+ * Copyright (C) 2007 Rainer Gerhards
  *
- * Author: Eric Allman
- * Modified to use UNIX domain IPC by Ralph Campbell
+ * This program 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 2
+ * of the License, or (at your option) any later version.
  *
- * Sat Dec 11 11:58:31 CST 1993: Dr. Wettstein
- *	Changes to allow compilation with no complains under -Wall.
+ * This program 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.
  *
- * Thu Jan 18 11:16:11 CST 1996: Dr. Wettstein
- *	Added patch to close potential security hole.  This is the same
- *	patch which was announced in the linux-security mailing lists
- *	and incorporated into the libc version of syslog.c.
- *
- * Sun Mar 11 20:23:44 CET 2001: Martin Schulze <joey@infodrom.ffis.de>
- *	Use SOCK_DGRAM for loggin, renables it to work.	
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  *
+ * A copy of the GPL can be found in the file "COPYING" in this distribution.
  */
-
-#include <sys/types.h>
+#include <stdio.h>
+#include <assert.h>
 #include <sys/socket.h>
-#include <sys/file.h>
-#include <sys/signal.h>
-#include <sys/syslog.h>
-#undef   syslog
-#undef   vsyslog
-#if 0
-#include "syslog.h"
-#include "pathnames.h"
-#endif
-
-#include <sys/uio.h>
-#include <sys/wait.h>
-#include <netdb.h>
 #include <string.h>
 #include <time.h>
-#include <unistd.h>
-#include <errno.h>
 #include <stdarg.h>
-#include <paths.h>
-#include <stdio.h>
+#include <unistd.h>
 
-#define	_PATH_LOGNAME	"/dev/log"
+#define PATH_LOGNAME "/dev/log"		/* be sure you know what you do if you change this! */
 
-static int	LogFile = -1;		/* fd for log */
-static int	connected;		/* have done connect */
-static int	LogStat = 0;		/* status bits, set by openlog() */
-static const char *LogTag = "syslog";	/* string to tag the entry with */
-static int	LogFacility = LOG_USER;	/* default facility code */
+static struct sockaddr LoggerAddr;	/* AF_UNIX address of local logger */
+static int connected;			/* have done connect */
+static int fdLog = -1;			/* fd for log - -1 if closed */
 
-void
-syslog(int pri, const char *fmt, ...)
+/* klogOpenLog
+ * opens the system log for writing. The log is opened immediately.
+ * If it is already open, no action is taken)
+ */
+static void klogOpenlog(void)
 {
-	va_list ap;
-
-	va_start(ap, fmt);
-	vsyslog(pri, fmt, ap);
-	va_end(ap);
+	if (fdLog == -1) {
+		LoggerAddr.sa_family = AF_UNIX;
+		strncpy(LoggerAddr.sa_data, PATH_LOGNAME, sizeof(LoggerAddr.sa_data));
+		fdLog = socket(AF_UNIX, SOCK_DGRAM, 0);
+	}
+	if (fdLog != -1 && !connected)
+		if(connect(fdLog, &LoggerAddr, sizeof(LoggerAddr.sa_family) +
+		    sizeof(PATH_LOGNAME) - 1 /* for \0 byte!*/ ) != -1)
+		connected = 1;
 }
 
-void
-vsyslog(pri, fmt, ap)
-	int pri;
-	const char *fmt;
-	va_list ap;
+/* Close the log file if it is currently open.
+ */
+static void klogCloselog(void)
 {
-	register int cnt;
-	register char *p;
-	time_t now;
-	int fd, saved_errno;
-	char tbuf[2048], fmt_cpy[1024], *stdp = (char *) 0;
+	if(fdLog != -1)
+		close(fdLog);
+	fdLog = -1;
+	connected = 0;
+}
 
-	saved_errno = errno;
+/* Write a message to the syslogd.
+ * returns -1 if it fails, something else otherwise
+ */
+int writeSyslogV(int iPRI, const char *szFmt, va_list va)
+{
+	int iChars;
+	int iLen;
+	time_t tNow;
+	int iWritten;	/* number of bytes written */
+	char msgBuf[2048]; /* we use the same size as sysklogd to remain compatible */
 
-	/* see if we should just throw out this message */
-	if (!LOG_MASK(LOG_PRI(pri)) || (pri &~ (LOG_PRIMASK|LOG_FACMASK)))
-		return;
-	if (LogFile < 0 || !connected)
-		openlog(LogTag, LogStat | LOG_NDELAY, LogFacility);
+	assert(szFmt != NULL);
 
-	/* set default facility if none specified */
-	if ((pri & LOG_FACMASK) == 0)
-		pri |= LogFacility;
+	if (fdLog < 0 || !connected)
+		klogOpenlog();
 
 	/* build the message */
-	(void)time(&now);
-	(void)sprintf(tbuf, "<%d>%.15s ", pri, ctime(&now) + 4);
-	for (p = tbuf; *p; ++p);
-	if (LogStat & LOG_PERROR)
-		stdp = p;
-	if (LogTag) {
-		(void)strcpy(p, LogTag);
-		for (; *p; ++p);
-	}
-	if (LogStat & LOG_PID) {
-		(void)sprintf(p, "[%d]", getpid());
-		for (; *p; ++p);
-	}
-	if (LogTag) {
-		*p++ = ':';
-		*p++ = ' ';
-	}
-
-	/* substitute error message for %m */
-	{
-		register char ch, *t1, *t2;
-		char *strerror();
-
-		for (t1 = fmt_cpy;
-		     (ch = *fmt) != '\0' && t1<fmt_cpy+sizeof(fmt_cpy);
-		     ++fmt)
-			if (ch == '%' && fmt[1] == 'm') {
-				++fmt;
-				for (t2 = strerror(saved_errno);
-				    (*t1 = *t2++); ++t1);
-			}
-			else
-				*t1++ = ch;
-		*t1 = '\0';
-	}
-
-	(void)vsprintf(p, fmt_cpy, ap);
-
-	cnt = strlen(tbuf);
-
-	/* output to stderr if requested */
-	if (LogStat & LOG_PERROR) {
-		struct iovec iov[2];
-		register struct iovec *v = iov;
+	time(&tNow);
+	/* we can use sprintf safely below, because we know the size of the constants.
+	 * By doing so, we save some cpu cycles and code complexity (for unnecessary
+	 * error checking).
+	 */
+	iLen = sprintf(msgBuf, "<%d>%.15s kernel: ", iPRI, ctime(&tNow) + 4);
 
-		v->iov_base = stdp;
-		v->iov_len = cnt - (stdp - tbuf);
-		++v;
-		v->iov_base = "\n";
-		v->iov_len = 1;
-		(void)writev(2, iov, 2);
-	}
+	iChars = vsnprintf(msgBuf + iLen, sizeof(msgBuf) / sizeof(char) - iLen, szFmt, va);
+	if(iChars > sizeof(msgBuf) / sizeof(char) - iLen)
+		iLen = sizeof(msgBuf) / sizeof(char) - 1; /* full buffer siz minus \0 byte */
+	else
+		iLen += iChars;
 
 	/* output the message to the local logger */
-	if (write(LogFile, tbuf, cnt + 1) >= 0 || !(LogStat&LOG_CONS))
-		return;
+	iWritten = write(fdLog, msgBuf, iLen);
+	/* Debug aid below - uncomment to use
+	printf("wrote to log(%d): '%s'\n", iWritten, msgBuf); */
+
+	if(iWritten == -1) {
+		/* retry */
+		klogCloselog();
+		klogOpenlog();
+		iWritten = write(fdLog, msgBuf, iLen);
+	}
 
-	/*
-	 * output the message to the console; don't worry about
-	 * blocking, if console blocks everything will.
-	 */
-	if ((fd = open(_PATH_CONSOLE, O_WRONLY|O_NOCTTY, 0)) < 0)
-		return;
-	(void)strcat(tbuf, "\r\n");
-	cnt += 2;
-	p = index(tbuf, '>') + 1;
-	(void)write(fd, p, cnt - (p - tbuf));
-	(void)close(fd);
+	return(iWritten);
 }
 
-#ifndef TESTING
-static struct sockaddr SyslogAddr;	/* AF_UNIX address of local logger */
-#endif
-/*
- * OPENLOG -- open system log
- */
-void
-openlog(ident, logstat, logfac)
-	const char *ident;
-	int logstat, logfac;
+/* And now the same with variable arguments */
+int writeSyslog(int iPRI, const char *szFmt, ...)
 {
-	if (ident != NULL)
-		LogTag = ident;
-	LogStat = logstat;
-
-#ifdef ALLOW_KERNEL_LOGGING
-	if ((logfac &~ LOG_FACMASK) == 0)
-#else
-	if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
-#endif
-		LogFacility = logfac;
-
-#ifndef TESTING
-	if (LogFile == -1) {
-		SyslogAddr.sa_family = AF_UNIX;
-		strncpy(SyslogAddr.sa_data, _PATH_LOGNAME,
-		    sizeof(SyslogAddr.sa_data));
-		if (LogStat & LOG_NDELAY) {
-			LogFile = socket(AF_UNIX, SOCK_DGRAM, 0);
-/*			fcntl(LogFile, F_SETFD, 1); */
-		}
-	}
-	if (LogFile != -1 && !connected &&
-	    connect(LogFile, &SyslogAddr, sizeof(SyslogAddr.sa_family)+
-			strlen(SyslogAddr.sa_data)) != -1)
-#else
-	  LogFile = fileno(stdout);
-#endif
-		connected = 1;
-}
+	int iRet;
+	va_list va;
 
-/*
- * CLOSELOG -- close the system log
- */
-void
-closelog()
-{
-#ifndef TESTING
-	(void) close(LogFile);
-#endif
-	LogFile = -1;
-	connected = 0;
+	assert(szFmt != NULL);
+	va_start(va, szFmt);
+	iRet = writeSyslogV(iPRI, szFmt, va);
+	va_end(va);
+
+	return(iRet);
 }
 
-static int	LogMask = 0xff;		/* mask of priorities to be logged */
 /*
- * SETLOGMASK -- set the log mask level
+ * Local variables:
+ *  c-indent-level: 4
+ *  c-basic-offset: 4
+ *  tab-width: 4
+ * End:
+ * vi:set ai:
  */
-int
-setlogmask(pmask)
-	int pmask;
-{
-	int omask;
-
-	omask = LogMask;
-	if (pmask != 0)
-		LogMask = pmask;
-	return (omask);
-}