syslog-nb

syslog-nb.cpp

/*
 * Copyright (c) 1983, 1988, 1993
 *	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 defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)syslog-nb.c	8.4 (Berkeley) 3/18/94";
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/uio.h>	// for writev
#include <sys/un.h>

#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <stdlib.h>
#include <pthread.h>

#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif
#include <sys/time.h>
#include "syslog-nb.h"

#define ftell(s) INTUSE(_IO_ftell) (s)

static int	LogType = SOCK_DGRAM;	/* type of socket connection */
static int	LogFile = -1;		/* fd for log */
static int	connected;		/* have done connect */
static int	LogStat;		/* status bits, set by openlog() */
static const char *LogTag;		/* string to tag the entry with */
static int	LogFacility = LOG_USER;	/* default facility code */
static int	LogMask = 0xff;		/* mask of priorities to be logged */
extern char	*__progname;		/* Program name, from crt0. */

static const size_t LOG_MAXLEN = 2048;	/* 2048 should be enough */

static pthread_mutex_t syslog_lock = PTHREAD_MUTEX_INITIALIZER;

static void openlog_internal_nb(const char *, int, int);
static void closelog_internal_nb(void);
static void __syslog_chk_nb(int pri, int flag, const char *fmt, ...);
static void __vsyslog_chk_nb(int pri, int flag, const char *fmt, va_list ap);

static void
cancel_handler (void *ptr)
{
	/*  Free the lock.  */
	if (ptr != NULL)
		free(ptr);
	pthread_mutex_unlock(&syslog_lock);
}

/*
 * syslog, vsyslog --
 *	print message on log file; output is intended for syslogd(8).
 */
void
syslog_nb(int pri, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	__vsyslog_chk_nb(pri, -1, fmt, ap);
	va_end(ap);
}

static void
__syslog_chk_nb(int pri, int flag, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	__vsyslog_chk_nb(pri, flag, fmt, ap);
	va_end(ap);
}

static void
__vsyslog_chk_nb(int pri, int flag, const char *fmt, va_list ap)
{
	struct tm now_tm;
	time_t now;
	int fd;
//	FILE *f;
	char *buf = 0;
	size_t bufsize = 0;
	size_t prioff, msgoff;
	int len = 0;
	int saved_errno = errno;
	char failbuf[3 * sizeof (pid_t) + sizeof "out of memory []"];

#define	INTERNALLOG	LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
	/* Check for invalid bits. */
	if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
		syslog_nb(INTERNALLOG, "syslog: unknown facility/priority: %x", pri);
		pri &= LOG_PRIMASK|LOG_FACMASK;
	}

	/* Check priority against setlogmask values. */
	if ((LOG_MASK (LOG_PRI (pri)) & LogMask) == 0)
		return;

	/* Set default facility if none specified. */
	if ((pri & LOG_FACMASK) == 0)
		pri |= LogFacility;

	/* build the message in a memory buffer */
	/* we are not in glibc, that's much convenience, haha */
	buf = (char*)malloc(LOG_MAXLEN);
	if (buf == NULL) {
		pid_t pid = getpid();
		bufsize = snprintf(failbuf, sizeof(failbuf), "out of memory [%d]", pid) + 1;
		buf = failbuf;
		msgoff = 0;
	}
	else {
		/* format should be "<pri>Jan 16 12:13:14 progname[pid]: xxxxxxxxx" */
		bufsize = snprintf(buf, LOG_MAXLEN, "<%d>", pri);
		prioff = bufsize;
		time(&now);
		bufsize += strftime(buf + bufsize, LOG_MAXLEN - bufsize, "%h %e %T ",
							localtime_r(&now, &now_tm));
		msgoff = bufsize;

		if (LogTag == NULL)
			LogTag = __progname;
		if (LogTag == NULL){
			if (LogStat & LOG_PID) {
				bufsize += snprintf(buf + bufsize, LOG_MAXLEN - bufsize, "[%d]",
									(int)getpid());
			}
		}
		else {
			if (LogStat & LOG_PID)
				bufsize += snprintf(buf + bufsize, LOG_MAXLEN - bufsize, "%s[%d]: ",
									LogTag, (int)getpid());
			else
				bufsize += snprintf(buf + bufsize, LOG_MAXLEN - bufsize, "%s: ",
									LogTag);

		}
		//set_error(saved_errno);
		errno = saved_errno;
		// this may fail, for exmaple, the fmt is illegal, 
		// in this case, some char has already printed in
		if ( (len = vsnprintf(buf + bufsize, LOG_MAXLEN - bufsize, fmt, ap)) < 0){
			bufsize += snprintf(buf + bufsize, LOG_MAXLEN - bufsize, "illegal format string:\"%s\"", fmt);
		}
		else {
			bufsize += len;
		}
		if (bufsize > LOG_MAXLEN) {
			// buffer overflow, just trunc it
			bufsize = LOG_MAXLEN - 1; // last char is '\0'
		}
	}
	/* Output to stderr if requested. */
	if (LogStat & LOG_PERROR) {
		struct iovec iov[2];
		register struct iovec *v = iov;

		v->iov_base = buf + msgoff;
		v->iov_len = bufsize - msgoff;
		/* Append a newline if necessary.  */
		if (buf[bufsize - 1] != '\n') {
			++v;
			v->iov_base = (char *) "\n";
			v->iov_len = 1;
		}

		/* writev is a cancellation point.  */
		pthread_cleanup_push (free, buf == failbuf ? NULL : buf);
		writev(STDERR_FILENO, iov, v - iov + 1);
		pthread_cleanup_pop(0);
	}

	/* Prepare for multiple users.  We have to take care: open and
	   write are cancellation points.  */
	pthread_cleanup_push (cancel_handler, buf == failbuf ? NULL : buf);
	pthread_mutex_lock(&syslog_lock);

	/* Get connected, output the message to the local logger. */
	if (!connected)
		openlog_internal_nb(LogTag, LogStat | LOG_NDELAY | LOG_PID  , 0);

	/* If we have a SOCK_STREAM connection, also send ASCII NUL as
	   a record terminator.  */
	if (LogType == SOCK_STREAM)
		++bufsize;

	if (!connected || (send(LogFile, buf, bufsize, MSG_NOSIGNAL|MSG_DONTWAIT) < 0 && errno != EAGAIN )) {
	    if (connected){
		/* Try to reopen the syslog connection.  Maybe it went down.  */
			closelog_internal_nb();
			openlog_internal_nb(LogTag, LogStat | LOG_NDELAY | LOG_PID, 0);
		}

	    if (!connected || (send(LogFile, buf, bufsize, MSG_NOSIGNAL|MSG_DONTWAIT) < 0 && errno != EAGAIN )) {
			closelog_internal_nb();	/* attempt re-open next time */
			/*
			 * Output the message to the console; don't worry about blocking, 
			 * if console blocks everything will. Make sure the error reported 
			 * is the one from the syslogd failure.
			 */
			if (LogStat & LOG_CONS && (fd = open(_PATH_CONSOLE, O_WRONLY|O_NOCTTY, 0)) >= 0) {
				dprintf (fd, "%s\r\n", buf + msgoff);
				(void)close(fd);
			}
		}
	}

	/* End of critical section.  */
	pthread_cleanup_pop(0);
	pthread_mutex_unlock(&syslog_lock);

	if (buf != failbuf)
		free (buf);
}

void
vsyslog_nb(int pri, const char *fmt, va_list ap)
{
  __vsyslog_chk_nb(pri, -1, fmt, ap);
}

static struct sockaddr_un SyslogAddr;	/* AF_UNIX address of local logger */

static void
openlog_internal_nb(const char *ident, int logstat, int logfac)
{
	if (ident != NULL)
		LogTag = ident;
	LogStat = logstat;
	if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
		LogFacility = logfac;

	int retry = 0;
	while (retry < 2) {
		if (LogFile == -1) {
			SyslogAddr.sun_family = AF_UNIX;
			strncpy(SyslogAddr.sun_path, _PATH_LOG, sizeof(SyslogAddr.sun_path));
			if (LogStat & LOG_NDELAY) {
				LogFile = socket(AF_UNIX, LogType, 0);
				if (LogFile == -1)
					return;
				fcntl(LogFile, F_SETFD, FD_CLOEXEC);
			}
		}
		if (LogFile != -1 && !connected)
		{
			int old_errno = errno;
			if (connect(LogFile, (struct sockaddr*)&SyslogAddr, sizeof(SyslogAddr)) == -1)
			{
				int saved_errno = errno;
				int fd = LogFile;
				LogFile = -1;
				close(fd);
				//__set_errno (old_errno);
				errno = old_errno;
				if (saved_errno == EPROTOTYPE)
				{
					/* retry with the other type: */
					LogType = (LogType == SOCK_DGRAM ? SOCK_STREAM : SOCK_DGRAM);
					++retry;
					continue;
				}
			} else
				connected = 1;
		}
		break;
	}
}

void
openlog_nb (const char *ident, int logstat, int logfac)
{
  /* Protect against multiple users and cancellation.  */
  pthread_mutex_lock(&syslog_lock);

  openlog_internal_nb(ident, logstat, logfac);

  pthread_mutex_unlock(&syslog_lock);
}

static void
closelog_internal_nb()
{
  if (!connected)
    return;

  close (LogFile);
  LogFile = -1;
  connected = 0;
}

void
closelog_nb ()
{
  /* Protect against multiple users and cancellation.  */
  pthread_mutex_lock(&syslog_lock);

  closelog_internal_nb();
  LogTag = NULL;
  LogType = SOCK_DGRAM; /* this is the default */

  /* Free the lock.  */
  pthread_mutex_unlock(&syslog_lock);
}

/* setlogmask -- set the log mask level */
int
setlogmask_nb(int pmask)
{
	int omask;

	omask = LogMask;
	if (pmask != 0)
		LogMask = pmask;
	return (omask);
}

syslog-nb.h

/*
 * Copyright (c) 1982, 1986, 1988, 1993
 *	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.
 *
 *	@(#)syslog.h	8.1 (Berkeley) 6/2/93
 */

#ifndef _SYS_SYSLOGNG_H
#define _SYS_SYSLOGNG_H 1
#include <sys/syslog.h>
#include <stdarg.h>

#if 0
#define _PATH_LOG       "/dev/log"
/*
 * priorities/facilities are encoded into a single 32-bit quantity, where the
 * bottom 3 bits are the priority (0-7) and the top 28 bits are the facility
 * (0-big number).  Both the priorities and the facilities map roughly
 * one-to-one to strings in the syslogd(8) source code.  This mapping is
 * included in this file.
 *
 * priorities (these are ordered)
 */
#define	LOG_EMERG	0	/* system is unusable */
#define	LOG_ALERT	1	/* action must be taken immediately */
#define	LOG_CRIT	2	/* critical conditions */
#define	LOG_ERR		3	/* error conditions */
#define	LOG_WARNING	4	/* warning conditions */
#define	LOG_NOTICE	5	/* normal but significant condition */
#define	LOG_INFO	6	/* informational */
#define	LOG_DEBUG	7	/* debug-level messages */

#define	LOG_PRIMASK	0x07	/* mask to extract priority part (internal) */
				/* extract priority */
#define	LOG_PRI(p)	((p) & LOG_PRIMASK)
#define	LOG_MAKEPRI(fac, pri)	(((fac) << 3) | (pri))

#define	INTERNAL_NOPRI	0x10	/* the "no priority" priority */
				/* mark "facility" */
#define	INTERNAL_MARK	LOG_MAKEPRI(LOG_NFACILITIES, 0)
typedef struct _code {
	char	*c_name;
	int	c_val;
} CODE;

CODE prioritynames[] =
  {
    { "alert", LOG_ALERT },
    { "crit", LOG_CRIT },
    { "debug", LOG_DEBUG },
    { "emerg", LOG_EMERG },
    { "err", LOG_ERR },
    { "error", LOG_ERR },		/* DEPRECATED */
    { "info", LOG_INFO },
    { "none", INTERNAL_NOPRI },		/* INTERNAL */
    { "notice", LOG_NOTICE },
    { "panic", LOG_EMERG },		/* DEPRECATED */
    { "warn", LOG_WARNING },		/* DEPRECATED */
    { "warning", LOG_WARNING },
    { NULL, -1 }
  };

/* facility codes */
#define	LOG_KERN	(0<<3)	/* kernel messages */
#define	LOG_USER	(1<<3)	/* random user-level messages */
#define	LOG_MAIL	(2<<3)	/* mail system */
#define	LOG_DAEMON	(3<<3)	/* system daemons */
#define	LOG_AUTH	(4<<3)	/* security/authorization messages */
#define	LOG_SYSLOG	(5<<3)	/* messages generated internally by syslogd */
#define	LOG_LPR		(6<<3)	/* line printer subsystem */
#define	LOG_NEWS	(7<<3)	/* network news subsystem */
#define	LOG_UUCP	(8<<3)	/* UUCP subsystem */
#define	LOG_CRON	(9<<3)	/* clock daemon */
#define	LOG_AUTHPRIV	(10<<3)	/* security/authorization messages (private) */
#define	LOG_FTP		(11<<3)	/* ftp daemon */

	/* other codes through 15 reserved for system use */
#define	LOG_LOCAL0	(16<<3)	/* reserved for local use */
#define	LOG_LOCAL1	(17<<3)	/* reserved for local use */
#define	LOG_LOCAL2	(18<<3)	/* reserved for local use */
#define	LOG_LOCAL3	(19<<3)	/* reserved for local use */
#define	LOG_LOCAL4	(20<<3)	/* reserved for local use */
#define	LOG_LOCAL5	(21<<3)	/* reserved for local use */
#define	LOG_LOCAL6	(22<<3)	/* reserved for local use */
#define	LOG_LOCAL7	(23<<3)	/* reserved for local use */

#define	LOG_NFACILITIES	24	/* current number of facilities */
#define	LOG_FACMASK	0x03f8	/* mask to extract facility part */
				/* facility of pri */
#define	LOG_FAC(p)	(((p) & LOG_FACMASK) >> 3)

CODE facilitynames[] =
  {
    { "auth", LOG_AUTH },
    { "authpriv", LOG_AUTHPRIV },
    { "cron", LOG_CRON },
    { "daemon", LOG_DAEMON },
    { "ftp", LOG_FTP },
    { "kern", LOG_KERN },
    { "lpr", LOG_LPR },
    { "mail", LOG_MAIL },
    { "mark", INTERNAL_MARK },		/* INTERNAL */
    { "news", LOG_NEWS },
    { "security", LOG_AUTH },		/* DEPRECATED */
    { "syslog", LOG_SYSLOG },
    { "user", LOG_USER },
    { "uucp", LOG_UUCP },
    { "local0", LOG_LOCAL0 },
    { "local1", LOG_LOCAL1 },
    { "local2", LOG_LOCAL2 },
    { "local3", LOG_LOCAL3 },
    { "local4", LOG_LOCAL4 },
    { "local5", LOG_LOCAL5 },
    { "local6", LOG_LOCAL6 },
    { "local7", LOG_LOCAL7 },
    { NULL, -1 }
  };

/*
 * arguments to setlogmask.
 */
#define	LOG_MASK(pri)	(1 << (pri))		/* mask for one priority */
#define	LOG_UPTO(pri)	((1 << ((pri)+1)) - 1)	/* all priorities through pri */

/*
 * Option flags for openlog.
 *
 * LOG_ODELAY no longer does anything.
 * LOG_NDELAY is the inverse of what it used to be.
 */
#define	LOG_PID		0x01	/* log the pid with each message */
#define	LOG_CONS	0x02	/* log on the console if errors in sending */
#define	LOG_ODELAY	0x04	/* delay open until first syslog() (default) */
#define	LOG_NDELAY	0x08	/* don't delay open */
#define	LOG_NOWAIT	0x10	/* don't wait for console forks: DEPRECATED */
#define	LOG_PERROR	0x20	/* log to stderr as well */

#endif

__BEGIN_DECLS

/* Close descriptor used to write to system logger.

   This function is a possible cancellation point and therefore not
   marked with __THROW.  */
extern void closelog_nb (void);

/* Open connection to system logger.

   This function is a possible cancellation point and therefore not
   marked with __THROW.  */
extern void openlog_nb (const char *__ident, int __option, int __facility);

/* Set the log mask level.  */
extern int setlogmask_nb (int __mask);

/* Generate a log message using FMT string and option arguments.

   This function is a possible cancellation point and therefore not
   marked with __THROW.  */
extern void syslog_nb (int __pri, const char *__fmt, ...)
     __attribute__ ((__format__ (__printf__, 2, 3)));

#ifdef __USE_BSD
/* Generate a log message using FMT and using arguments pointed to by AP.

   This function is not part of POSIX and therefore no official
   cancellation point.  But due to similarity with an POSIX interface
   or due to the implementation it is a cancellation point and
   therefore not marked with __THROW.  */
extern void vsyslog_nb (int __pri, __const char *__fmt, __gnuc_va_list __ap)
     __attribute__ ((__format__ (__printf__, 2, 0)));
#endif

__END_DECLS

#endif /* sys/syslog.h */