xref: /freebsd/lib/libc/gen/syslog.c (revision 8e6b01171e30297084bb0b4457c4183c2746aacc)
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 /*
36 static char sccsid[] = "From: @(#)syslog.c	8.4 (Berkeley) 3/18/94";
37 */
38 static const char rcsid[] =
39   "$Id: syslog.c,v 1.6 1995/10/21 07:05:01 peter Exp $";
40 #endif /* LIBC_SCCS and not lint */
41 
42 #include <sys/types.h>
43 #include <sys/socket.h>
44 #include <sys/syslog.h>
45 #include <sys/uio.h>
46 #include <netdb.h>
47 
48 #include <errno.h>
49 #include <fcntl.h>
50 #include <paths.h>
51 #include <stdio.h>
52 #include <string.h>
53 #include <time.h>
54 #include <unistd.h>
55 
56 #if __STDC__
57 #include <stdarg.h>
58 #else
59 #include <varargs.h>
60 #endif
61 
62 static int	LogFile = -1;		/* fd for log */
63 static int	connected;		/* have done connect */
64 static int	LogStat = 0;		/* status bits, set by openlog() */
65 static const char *LogTag = NULL;	/* string to tag the entry with */
66 static int	LogFacility = LOG_USER;	/* default facility code */
67 static int	LogMask = 0xff;		/* mask of priorities to be logged */
68 extern char	*__progname;		/* Program name, from crt0. */
69 
70 /*
71  * Format of the magic cookie passed through the stdio hook
72  */
73 struct bufcookie {
74 	char	*base;	/* start of buffer */
75 	int	left;
76 };
77 
78 /*
79  * stdio write hook for writing to a static string buffer
80  * XXX: Maybe one day, dynamically allocate it so that the line length
81  *      is `unlimited'.
82  */
83 static writehook(cookie, buf, len)
84 	void	*cookie;	/* really [struct bufcookie *] */
85 	char	*buf;		/* characters to copy */
86 	int	len;		/* length to copy */
87 {
88 	struct bufcookie *h;	/* private `handle' */
89 
90 	h = (struct bufcookie *)cookie;
91 	if (len > h->left) {
92 		/* clip in case of wraparound */
93 		len = h->left;
94 	}
95 	if (len > 0) {
96 		(void)memcpy(h->base, buf, len); /* `write' it. */
97 		h->base += len;
98 		h->left -= len;
99 	}
100 	return 0;
101 }
102 
103 /*
104  * syslog, vsyslog --
105  *	print message on log file; output is intended for syslogd(8).
106  */
107 void
108 #if __STDC__
109 syslog(int pri, const char *fmt, ...)
110 #else
111 syslog(pri, fmt, va_alist)
112 	int pri;
113 	char *fmt;
114 	va_dcl
115 #endif
116 {
117 	va_list ap;
118 
119 #if __STDC__
120 	va_start(ap, fmt);
121 #else
122 	va_start(ap);
123 #endif
124 	vsyslog(pri, fmt, ap);
125 	va_end(ap);
126 }
127 
128 void
129 vsyslog(pri, fmt, ap)
130 	int pri;
131 	register const char *fmt;
132 	va_list ap;
133 {
134 	register int cnt;
135 	register char ch, *p;
136 	time_t now;
137 	int fd, saved_errno;
138 	char *stdp, tbuf[2048], fmt_cpy[1024];
139 	FILE *fp, *fmt_fp;
140 	struct bufcookie tbuf_cookie;
141 	struct bufcookie fmt_cookie;
142 
143 #define	INTERNALLOG	LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
144 	/* Check for invalid bits. */
145 	if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
146 		syslog(INTERNALLOG,
147 		    "syslog: unknown facility/priority: %x", pri);
148 		pri &= LOG_PRIMASK|LOG_FACMASK;
149 	}
150 
151 	/* Check priority against setlogmask values. */
152 	if (!(LOG_MASK(LOG_PRI(pri)) & LogMask))
153 		return;
154 
155 	saved_errno = errno;
156 
157 	/* Set default facility if none specified. */
158 	if ((pri & LOG_FACMASK) == 0)
159 		pri |= LogFacility;
160 
161 	/* Create the primary stdio hook */
162 	tbuf_cookie.base = tbuf;
163 	tbuf_cookie.left = sizeof(tbuf);
164 	fp = fwopen(&tbuf_cookie, writehook);
165 	if (fp == NULL)
166 		return;
167 
168 	/* Build the message. */
169 	(void)time(&now);
170 	(void)fprintf(fp, "<%d>", pri);
171 	(void)fprintf(fp, "%.15s ", ctime(&now) + 4);
172 	if (LogStat & LOG_PERROR) {
173 		/* Transfer to string buffer */
174 		(void)fflush(fp);
175 		stdp = tbuf + (sizeof(tbuf) - tbuf_cookie.left);
176 	}
177 	if (LogTag == NULL)
178 		LogTag = __progname;
179 	if (LogTag != NULL)
180 		(void)fprintf(fp, "%s", LogTag);
181 	if (LogStat & LOG_PID)
182 		(void)fprintf(fp, "[%d]", getpid());
183 	if (LogTag != NULL) {
184 		(void)fprintf(fp, ": ");
185 	}
186 
187 	/* Check to see if we can skip expanding the %m */
188 	if (strstr(fmt, "%m")) {
189 
190 		/* Create the second stdio hook */
191 		fmt_cookie.base = fmt_cpy;
192 		fmt_cookie.left = sizeof(fmt_cpy) - 1;
193 		fmt_fp = fwopen(&fmt_cookie, writehook);
194 		if (fmt_fp == NULL) {
195 			fclose(fp);
196 			return;
197 		}
198 
199 		/* Substitute error message for %m. */
200 		for ( ; ch = *fmt; ++fmt)
201 			if (ch == '%' && fmt[1] == 'm') {
202 				++fmt;
203 				fputs(strerror(saved_errno), fmt_fp);
204 			} else
205 				fputc(ch, fmt_fp);
206 
207 		/* Null terminate if room */
208 		fputc(0, fmt_fp);
209 		fclose(fmt_fp);
210 
211 		/* Guarantee null termination */
212 		fmt_cpy[sizeof(fmt_cpy) - 1] = '\0';
213 
214 		fmt = fmt_cpy;
215 	}
216 
217 	(void)vfprintf(fp, fmt, ap);
218 	(void)fclose(fp);
219 
220 	cnt = sizeof(tbuf) - tbuf_cookie.left;
221 
222 	/* Output to stderr if requested. */
223 	if (LogStat & LOG_PERROR) {
224 		struct iovec iov[2];
225 		register struct iovec *v = iov;
226 
227 		v->iov_base = stdp;
228 		v->iov_len = cnt - (stdp - tbuf);
229 		++v;
230 		v->iov_base = "\n";
231 		v->iov_len = 1;
232 		(void)writev(STDERR_FILENO, iov, 2);
233 	}
234 
235 	/* Get connected, output the message to the local logger. */
236 	if (!connected)
237 		openlog(LogTag, LogStat | LOG_NDELAY, 0);
238 	if (send(LogFile, tbuf, cnt, 0) >= 0)
239 		return;
240 
241 	/*
242 	 * Output the message to the console; don't worry about blocking,
243 	 * if console blocks everything will.  Make sure the error reported
244 	 * is the one from the syslogd failure.
245 	 */
246 	if (LogStat & LOG_CONS &&
247 	    (fd = open(_PATH_CONSOLE, O_WRONLY, 0)) >= 0) {
248 		struct iovec iov[2];
249 		register struct iovec *v = iov;
250 
251 		p = strchr(tbuf, '>') + 1;
252 		v->iov_base = p;
253 		v->iov_len = cnt - (p - tbuf);
254 		++v;
255 		v->iov_base = "\r\n";
256 		v->iov_len = 2;
257 		(void)writev(fd, iov, 2);
258 		(void)close(fd);
259 	}
260 }
261 
262 static struct sockaddr SyslogAddr;	/* AF_UNIX address of local logger */
263 
264 void
265 openlog(ident, logstat, logfac)
266 	const char *ident;
267 	int logstat, logfac;
268 {
269 	if (ident != NULL)
270 		LogTag = ident;
271 	LogStat = logstat;
272 	if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
273 		LogFacility = logfac;
274 
275 	if (LogFile == -1) {
276 		SyslogAddr.sa_family = AF_UNIX;
277 		(void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
278 		    sizeof(SyslogAddr.sa_data));
279 		if (LogStat & LOG_NDELAY) {
280 			if ((LogFile = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1)
281 				return;
282 			(void)fcntl(LogFile, F_SETFD, 1);
283 		}
284 	}
285 	if (LogFile != -1 && !connected)
286 		if (connect(LogFile, &SyslogAddr, sizeof(SyslogAddr)) == -1) {
287 			(void)close(LogFile);
288 			LogFile = -1;
289 		} else
290 			connected = 1;
291 }
292 
293 void
294 closelog()
295 {
296 	(void)close(LogFile);
297 	LogFile = -1;
298 	connected = 0;
299 }
300 
301 /* setlogmask -- set the log mask level */
302 int
303 setlogmask(pmask)
304 	int pmask;
305 {
306 	int omask;
307 
308 	omask = LogMask;
309 	if (pmask != 0)
310 		LogMask = pmask;
311 	return (omask);
312 }
313