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syslog.c revision 1.20 
      1 /*	$NetBSD: syslog.c,v 1.20 1999/02/04 16:23:17 kleink Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1983, 1988, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 static char sccsid[] = "@(#)syslog.c	8.5 (Berkeley) 4/29/95";
     40 #else
     41 __RCSID("$NetBSD: syslog.c,v 1.20 1999/02/04 16:23:17 kleink Exp $");
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 #include "namespace.h"
     46 #include <sys/types.h>
     47 #include <sys/socket.h>
     48 #include <sys/syslog.h>
     49 #include <sys/uio.h>
     50 #include <netdb.h>
     51 
     52 #include <errno.h>
     53 #include <fcntl.h>
     54 #include <paths.h>
     55 #include <stdio.h>
     56 #include <string.h>
     57 #include <time.h>
     58 #include <unistd.h>
     59 #include "reentrant.h"
     60 
     61 #if __STDC__
     62 #include <stdarg.h>
     63 #else
     64 #include <varargs.h>
     65 #endif
     66 
     67 #ifdef __weak_alias
     68 __weak_alias(closelog,_closelog);
     69 __weak_alias(openlog,_openlog);
     70 __weak_alias(setlogmask,_setlogmask);
     71 __weak_alias(syslog,_syslog);
     72 __weak_alias(vsyslog,_vsyslog);
     73 #endif
     74 
     75 static int	LogFile = -1;		/* fd for log */
     76 static int	connected;		/* have done connect */
     77 static int	LogStat = 0;		/* status bits, set by openlog() */
     78 static const char *LogTag = NULL;	/* string to tag the entry with */
     79 static int	LogFacility = LOG_USER;	/* default facility code */
     80 static int	LogMask = 0xff;		/* mask of priorities to be logged */
     81 extern char	*__progname;		/* Program name, from crt0. */
     82 
     83 static void	openlog_unlocked __P((const char *, int, int));
     84 static void	closelog_unlocked __P((void));
     85 
     86 #ifdef _REENT
     87 static mutex_t	syslog_mutex = MUTEX_INITIALIZER;
     88 #endif
     89 
     90 #ifdef lint
     91 static const int ZERO = 0;
     92 #else
     93 #define ZERO	0
     94 #endif
     95 
     96 /*
     97  * syslog, vsyslog --
     98  *	print message on log file; output is intended for syslogd(8).
     99  */
    100 void
    101 #if __STDC__
    102 syslog(int pri, const char *fmt, ...)
    103 #else
    104 syslog(pri, fmt, va_alist)
    105 	int pri;
    106 	char *fmt;
    107 	va_dcl
    108 #endif
    109 {
    110 	va_list ap;
    111 
    112 #if __STDC__
    113 	va_start(ap, fmt);
    114 #else
    115 	va_start(ap);
    116 #endif
    117 	vsyslog(pri, fmt, ap);
    118 	va_end(ap);
    119 }
    120 
    121 void
    122 vsyslog(pri, fmt, ap)
    123 	int pri;
    124 	const char *fmt;
    125 	va_list ap;
    126 {
    127 	size_t cnt;
    128 	char ch, *p, *t;
    129 	time_t now;
    130 	struct tm tmnow;
    131 	int fd, saved_errno;
    132 #define	TBUF_LEN	2048
    133 #define	FMT_LEN		1024
    134 	char *stdp = NULL;	/* pacify gcc */
    135 	char tbuf[TBUF_LEN], fmt_cpy[FMT_LEN];
    136 	size_t tbuf_left, fmt_left, prlen;
    137 
    138 #define	INTERNALLOG	LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
    139 	/* Check for invalid bits. */
    140 	if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
    141 		syslog(INTERNALLOG,
    142 		    "syslog: unknown facility/priority: %x", pri);
    143 		pri &= LOG_PRIMASK|LOG_FACMASK;
    144 	}
    145 
    146 	/* Check priority against setlogmask values. */
    147 	if (!(LOG_MASK(LOG_PRI(pri)) & LogMask))
    148 		return;
    149 
    150 	saved_errno = errno;
    151 
    152 	/* Set default facility if none specified. */
    153 	if ((pri & LOG_FACMASK) == 0)
    154 		pri |= LogFacility;
    155 
    156 	/* Build the message. */
    157 
    158 	/*
    159  	 * Although it's tempting, we can't ignore the possibility of
    160 	 * overflowing the buffer when assembling the "fixed" portion
    161 	 * of the message.  Strftime's "%h" directive expands to the
    162 	 * locale's abbreviated month name, but if the user has the
    163 	 * ability to construct to his own locale files, it may be
    164 	 * arbitrarily long.
    165 	 */
    166 	(void)time(&now);
    167 
    168 	p = tbuf;
    169 	tbuf_left = TBUF_LEN;
    170 
    171 #define	DEC()							\
    172 	do {							\
    173 		if (prlen >= tbuf_left)				\
    174 			prlen = tbuf_left - 1;			\
    175 		p += prlen;					\
    176 		tbuf_left -= prlen;				\
    177 	} while (ZERO)
    178 
    179 	prlen = snprintf(p, tbuf_left, "<%d>", pri);
    180 	DEC();
    181 
    182 	tzset(); /* strftime() implies tzset(), localtime_r() doesn't. */
    183 	prlen = strftime(p, tbuf_left, "%h %e %T ", localtime_r(&now, &tmnow));
    184 	DEC();
    185 
    186 	if (LogStat & LOG_PERROR)
    187 		stdp = p;
    188 	if (LogTag == NULL)
    189 		LogTag = __progname;
    190 	if (LogTag != NULL) {
    191 		prlen = snprintf(p, tbuf_left, "%s", LogTag);
    192 		DEC();
    193 	}
    194 	if (LogStat & LOG_PID) {
    195 		prlen = snprintf(p, tbuf_left, "[%d]", getpid());
    196 		DEC();
    197 	}
    198 	if (LogTag != NULL) {
    199 		if (tbuf_left > 1) {
    200 			*p++ = ':';
    201 			tbuf_left--;
    202 		}
    203 		if (tbuf_left > 1) {
    204 			*p++ = ' ';
    205 			tbuf_left--;
    206 		}
    207 	}
    208 
    209 	/*
    210 	 * We wouldn't need this mess if printf handled %m, or if
    211 	 * strerror() had been invented before syslog().
    212 	 */
    213 	for (t = fmt_cpy, fmt_left = FMT_LEN; (ch = *fmt) != '\0'; ++fmt) {
    214 		if (ch == '%' && fmt[1] == 'm') {
    215 			++fmt;
    216 			prlen = snprintf(t, fmt_left, "%s",
    217 			    strerror(saved_errno));
    218 			if (prlen >= fmt_left)
    219 				prlen = fmt_left - 1;
    220 			t += prlen;
    221 			fmt_left -= prlen;
    222 		} else {
    223 			if (fmt_left > 1) {
    224 				*t++ = ch;
    225 				fmt_left--;
    226 			}
    227 		}
    228 	}
    229 	*t = '\0';
    230 
    231 	prlen = vsnprintf(p, tbuf_left, fmt_cpy, ap);
    232 	DEC();
    233 	cnt = p - tbuf;
    234 
    235 	/* Output to stderr if requested. */
    236 	if (LogStat & LOG_PERROR) {
    237 		struct iovec iov[2];
    238 
    239 		iov[0].iov_base = stdp;
    240 		iov[0].iov_len = cnt - (stdp - tbuf);
    241 		iov[1].iov_base = "\n";
    242 		iov[1].iov_len = 1;
    243 		(void)writev(STDERR_FILENO, iov, 2);
    244 	}
    245 
    246 	/* Get connected, output the message to the local logger. */
    247 	mutex_lock(&syslog_mutex);
    248 	if (!connected)
    249 		openlog_unlocked(LogTag, LogStat | LOG_NDELAY, 0);
    250 	if (send(LogFile, tbuf, cnt, 0) >= 0) {
    251 		mutex_unlock(&syslog_mutex);
    252 		return;
    253 	}
    254 	mutex_unlock(&syslog_mutex);
    255 
    256 	/*
    257 	 * Output the message to the console; don't worry about blocking,
    258 	 * if console blocks everything will.  Make sure the error reported
    259 	 * is the one from the syslogd failure.
    260 	 */
    261 	if (LogStat & LOG_CONS &&
    262 	    (fd = open(_PATH_CONSOLE, O_WRONLY, 0)) >= 0) {
    263 		struct iovec iov[2];
    264 
    265 		p = strchr(tbuf, '>') + 1;
    266 		iov[0].iov_base = p;
    267 		iov[0].iov_len = cnt - (p - tbuf);
    268 		iov[1].iov_base = "\r\n";
    269 		iov[1].iov_len = 2;
    270 		(void)writev(fd, iov, 2);
    271 		(void)close(fd);
    272 	}
    273 }
    274 
    275 static struct sockaddr SyslogAddr;	/* AF_LOCAL address of local logger */
    276 
    277 static void
    278 openlog_unlocked(ident, logstat, logfac)
    279 	const char *ident;
    280 	int logstat, logfac;
    281 {
    282 
    283 	if (ident != NULL)
    284 		LogTag = ident;
    285 	LogStat = logstat;
    286 	if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
    287 		LogFacility = logfac;
    288 
    289 	if (LogFile == -1) {
    290 		SyslogAddr.sa_family = AF_LOCAL;
    291 		(void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
    292 		    sizeof(SyslogAddr.sa_data));
    293 		if (LogStat & LOG_NDELAY) {
    294 			if ((LogFile = socket(AF_LOCAL, SOCK_DGRAM, 0)) == -1)
    295 				return;
    296 			(void)fcntl(LogFile, F_SETFD, 1);
    297 		}
    298 	}
    299 	if (LogFile != -1 && !connected) {
    300 		if (connect(LogFile, &SyslogAddr, sizeof(SyslogAddr)) == -1) {
    301 			(void)close(LogFile);
    302 			LogFile = -1;
    303 		} else
    304 			connected = 1;
    305 	}
    306 }
    307 
    308 void
    309 openlog(ident, logstat, logfac)
    310 	const char *ident;
    311 	int logstat, logfac;
    312 {
    313 
    314 	mutex_lock(&syslog_mutex);
    315 	openlog_unlocked(ident, logstat, logfac);
    316 	mutex_unlock(&syslog_mutex);
    317 }
    318 
    319 static void
    320 closelog_unlocked()
    321 {
    322 	(void)close(LogFile);
    323 	LogFile = -1;
    324 	connected = 0;
    325 }
    326 
    327 void
    328 closelog()
    329 {
    330 
    331 	mutex_lock(&syslog_mutex);
    332 	closelog_unlocked();
    333 	mutex_unlock(&syslog_mutex);
    334 }
    335 
    336 /* setlogmask -- set the log mask level */
    337 int
    338 setlogmask(pmask)
    339 	int pmask;
    340 {
    341 	int omask;
    342 
    343 	omask = LogMask;
    344 	if (pmask != 0)
    345 		LogMask = pmask;
    346 	return (omask);
    347 }
    348