xref: /openbsd-src/lib/libc/gen/syslog.c (revision a4afd6dad3fba28f80e70208181c06c482259988)
1 /*
2  * Copyright (c) 1983, 1988, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char rcsid[] = "$OpenBSD: syslog.c,v 1.2 1996/08/19 08:26:33 tholo Exp $";
36 #endif /* LIBC_SCCS and not lint */
37 
38 #include <sys/types.h>
39 #include <sys/socket.h>
40 #include <sys/syslog.h>
41 #include <sys/uio.h>
42 #include <netdb.h>
43 
44 #include <errno.h>
45 #include <fcntl.h>
46 #include <paths.h>
47 #include <stdio.h>
48 #include <string.h>
49 #include <time.h>
50 #include <unistd.h>
51 
52 #if __STDC__
53 #include <stdarg.h>
54 #else
55 #include <varargs.h>
56 #endif
57 
58 static int	LogFile = -1;		/* fd for log */
59 static int	connected;		/* have done connect */
60 static int	LogStat = 0;		/* status bits, set by openlog() */
61 static const char *LogTag = NULL;	/* string to tag the entry with */
62 static int	LogFacility = LOG_USER;	/* default facility code */
63 static int	LogMask = 0xff;		/* mask of priorities to be logged */
64 extern char	*__progname;		/* Program name, from crt0. */
65 
66 /*
67  * syslog, vsyslog --
68  *	print message on log file; output is intended for syslogd(8).
69  */
70 void
71 #if __STDC__
72 syslog(int pri, const char *fmt, ...)
73 #else
74 syslog(pri, fmt, va_alist)
75 	int pri;
76 	char *fmt;
77 	va_dcl
78 #endif
79 {
80 	va_list ap;
81 
82 #if __STDC__
83 	va_start(ap, fmt);
84 #else
85 	va_start(ap);
86 #endif
87 	vsyslog(pri, fmt, ap);
88 	va_end(ap);
89 }
90 
91 void
92 vsyslog(pri, fmt, ap)
93 	int pri;
94 	register const char *fmt;
95 	va_list ap;
96 {
97 	register int cnt;
98 	register char ch, *p, *t;
99 	time_t now;
100 	int fd, saved_errno;
101 #define	TBUF_LEN	2048
102 #define	FMT_LEN		1024
103 	char *stdp, tbuf[TBUF_LEN], fmt_cpy[FMT_LEN];
104 	int tbuf_left, fmt_left, prlen;
105 
106 #define	INTERNALLOG	LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
107 	/* Check for invalid bits. */
108 	if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
109 		syslog(INTERNALLOG,
110 		    "syslog: unknown facility/priority: %x", pri);
111 		pri &= LOG_PRIMASK|LOG_FACMASK;
112 	}
113 
114 	/* Check priority against setlogmask values. */
115 	if (!(LOG_MASK(LOG_PRI(pri)) & LogMask))
116 		return;
117 
118 	saved_errno = errno;
119 
120 	/* Set default facility if none specified. */
121 	if ((pri & LOG_FACMASK) == 0)
122 		pri |= LogFacility;
123 
124 	/* Build the message. */
125 
126 	/*
127  	 * Although it's tempting, we can't ignore the possibility of
128 	 * overflowing the buffer when assembling the "fixed" portion
129 	 * of the message.  Strftime's "%h" directive expands to the
130 	 * locale's abbreviated month name, but if the user has the
131 	 * ability to construct to his own locale files, it may be
132 	 * arbitrarily long.
133 	 */
134 	(void)time(&now);
135 
136 	p = tbuf;
137 	tbuf_left = TBUF_LEN;
138 
139 #define	DEC()	\
140 	do {					\
141 		if (prlen >= tbuf_left)		\
142 			prlen = tbuf_left - 1;	\
143 		p += prlen;			\
144 		tbuf_left -= prlen;		\
145 	} while (0)
146 
147 	prlen = snprintf(p, tbuf_left, "<%d>", pri);
148 	DEC();
149 
150 	prlen = strftime(p, tbuf_left, "%h %e %T ", localtime(&now));
151 	DEC();
152 
153 	if (LogStat & LOG_PERROR)
154 		stdp = p;
155 	if (LogTag == NULL)
156 		LogTag = __progname;
157 	if (LogTag != NULL) {
158 		prlen = snprintf(p, tbuf_left, "%s", LogTag);
159 		DEC();
160 	}
161 	if (LogStat & LOG_PID) {
162 		prlen = snprintf(p, tbuf_left, "[%d]", getpid());
163 		DEC();
164 	}
165 	if (LogTag != NULL) {
166 		if (tbuf_left > 1) {
167 			*p++ = ':';
168 			tbuf_left--;
169 		}
170 		if (tbuf_left > 1) {
171 			*p++ = ' ';
172 			tbuf_left--;
173 		}
174 	}
175 
176 	/*
177 	 * We wouldn't need this mess if printf handled %m, or if
178 	 * strerror() had been invented before syslog().
179 	 */
180 	for (t = fmt_cpy, fmt_left = FMT_LEN; ch = *fmt; ++fmt) {
181 		if (ch == '%' && fmt[1] == 'm') {
182 			++fmt;
183 			prlen = snprintf(t, fmt_left, "%s",
184 			    strerror(saved_errno));
185 			if (prlen >= fmt_left)
186 				prlen = fmt_left - 1;
187 			t += prlen;
188 			fmt_left -= prlen;
189 		} else {
190 			if (fmt_left > 1) {
191 				*t++ = ch;
192 				fmt_left--;
193 			}
194 		}
195 	}
196 	*t = '\0';
197 
198 	prlen = vsnprintf(p, tbuf_left, fmt_cpy, ap);
199 	DEC();
200 	cnt = p - tbuf;
201 
202 	/* Output to stderr if requested. */
203 	if (LogStat & LOG_PERROR) {
204 		struct iovec iov[2];
205 
206 		iov[0].iov_base = stdp;
207 		iov[0].iov_len = cnt - (stdp - tbuf);
208 		iov[1].iov_base = "\n";
209 		iov[1].iov_len = 1;
210 		(void)writev(STDERR_FILENO, iov, 2);
211 	}
212 
213 	/* Get connected, output the message to the local logger. */
214 	if (!connected)
215 		openlog(LogTag, LogStat | LOG_NDELAY, 0);
216 	if (send(LogFile, tbuf, cnt, 0) >= 0)
217 		return;
218 
219 	/*
220 	 * Output the message to the console; don't worry about blocking,
221 	 * if console blocks everything will.  Make sure the error reported
222 	 * is the one from the syslogd failure.
223 	 */
224 	if (LogStat & LOG_CONS &&
225 	    (fd = open(_PATH_CONSOLE, O_WRONLY, 0)) >= 0) {
226 		struct iovec iov[2];
227 
228 		p = strchr(tbuf, '>') + 1;
229 		iov[0].iov_base = p;
230 		iov[0].iov_len = cnt - (p - tbuf);
231 		iov[1].iov_base = "\r\n";
232 		iov[1].iov_len = 2;
233 		(void)writev(fd, iov, 2);
234 		(void)close(fd);
235 	}
236 }
237 
238 static struct sockaddr SyslogAddr;	/* AF_UNIX address of local logger */
239 
240 void
241 openlog(ident, logstat, logfac)
242 	const char *ident;
243 	int logstat, logfac;
244 {
245 	if (ident != NULL)
246 		LogTag = ident;
247 	LogStat = logstat;
248 	if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
249 		LogFacility = logfac;
250 
251 	if (LogFile == -1) {
252 		SyslogAddr.sa_family = AF_UNIX;
253 		(void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
254 		    sizeof(SyslogAddr.sa_data));
255 		if (LogStat & LOG_NDELAY) {
256 			if ((LogFile = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1)
257 				return;
258 			(void)fcntl(LogFile, F_SETFD, 1);
259 		}
260 	}
261 	if (LogFile != -1 && !connected)
262 		if (connect(LogFile, &SyslogAddr, sizeof(SyslogAddr)) == -1) {
263 			(void)close(LogFile);
264 			LogFile = -1;
265 		} else
266 			connected = 1;
267 }
268 
269 void
270 closelog()
271 {
272 	(void)close(LogFile);
273 	LogFile = -1;
274 	connected = 0;
275 }
276 
277 /* setlogmask -- set the log mask level */
278 int
279 setlogmask(pmask)
280 	int pmask;
281 {
282 	int omask;
283 
284 	omask = LogMask;
285 	if (pmask != 0)
286 		LogMask = pmask;
287 	return (omask);
288 }
289