2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1983, 1988, 1993
5 * The Regents of the University of California. All rights reserved.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 #if defined(LIBC_SCCS) && !defined(lint)
33 static char sccsid[] = "@(#)syslog.c 8.5 (Berkeley) 4/29/95";
34 #endif /* LIBC_SCCS and not lint */
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
38 #include "namespace.h"
39 #include <sys/param.h>
40 #include <sys/socket.h>
41 #include <sys/syslog.h>
58 #include "un-namespace.h"
60 #include "libc_private.h"
62 static int LogFile = -1; /* fd for log */
63 static int status; /* connection status */
64 static int opened; /* have done openlog() */
65 static int LogStat = 0; /* status bits, set by openlog() */
66 static const char *LogTag = NULL; /* string to tag the entry with */
67 static int LogFacility = LOG_USER; /* default facility code */
68 static int LogMask = 0xff; /* mask of priorities to be logged */
69 static pthread_mutex_t syslog_mutex = PTHREAD_MUTEX_INITIALIZER;
71 #define THREAD_LOCK() \
73 if (__isthreaded) _pthread_mutex_lock(&syslog_mutex); \
75 #define THREAD_UNLOCK() \
77 if (__isthreaded) _pthread_mutex_unlock(&syslog_mutex); \
80 static void disconnectlog(void); /* disconnect from syslogd */
81 static void connectlog(void); /* (re)connect to syslogd */
82 static void openlog_unlocked(const char *, int, int);
91 * Format of the magic cookie passed through the stdio hook
94 char *base; /* start of buffer */
99 * stdio write hook for writing to a static string buffer
100 * XXX: Maybe one day, dynamically allocate it so that the line length
104 writehook(void *cookie, const char *buf, int len)
106 struct bufcookie *h; /* private `handle' */
108 h = (struct bufcookie *)cookie;
110 /* clip in case of wraparound */
114 (void)memcpy(h->base, buf, len); /* `write' it. */
123 * print message on log file; output is intended for syslogd(8).
126 syslog(int pri, const char *fmt, ...)
131 vsyslog(pri, fmt, ap);
136 vsyslog1(int pri, const char *fmt, va_list ap)
142 int cnt, fd, saved_errno;
143 char hostname[MAXHOSTNAMELEN], *stdp, tbuf[2048], fmt_cpy[1024],
146 struct bufcookie tbuf_cookie;
147 struct bufcookie fmt_cookie;
149 #define INTERNALLOG LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
150 /* Check for invalid bits. */
151 if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
153 "syslog: unknown facility/priority: %x", pri);
154 pri &= LOG_PRIMASK|LOG_FACMASK;
159 /* Check priority against setlogmask values. */
160 if (!(LOG_MASK(LOG_PRI(pri)) & LogMask))
163 /* Set default facility if none specified. */
164 if ((pri & LOG_FACMASK) == 0)
167 /* Create the primary stdio hook */
168 tbuf_cookie.base = tbuf;
169 tbuf_cookie.left = sizeof(tbuf);
170 fp = fwopen(&tbuf_cookie, writehook);
174 /* Build the message according to RFC 5424. Tag and version. */
175 (void)fprintf(fp, "<%d>1 ", pri);
176 /* Timestamp similar to RFC 3339. */
177 if (gettimeofday(&now, NULL) == 0 &&
178 localtime_r(&now.tv_sec, &tm) != NULL) {
179 if (tm.tm_gmtoff < 0) {
181 tz_offset = -tm.tm_gmtoff;
184 tz_offset = tm.tm_gmtoff;
188 "%04d-%02d-%02d" /* Date. */
189 "T%02d:%02d:%02d.%06ld" /* Time. */
190 "%c%02ld:%02ld ", /* Time zone offset. */
191 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
192 tm.tm_hour, tm.tm_min, tm.tm_sec, now.tv_usec,
193 tz_sign, tz_offset / 3600, (tz_offset % 3600) / 60);
195 (void)fprintf(fp, "- ");
197 (void)gethostname(hostname, sizeof(hostname));
198 (void)fprintf(fp, "%s ", hostname);
199 if (LogStat & LOG_PERROR) {
200 /* Transfer to string buffer */
202 stdp = tbuf + (sizeof(tbuf) - tbuf_cookie.left);
205 * Application name, process ID, message ID and structured data.
206 * Provide the process ID regardless of whether LOG_PID has been
207 * specified, as it provides valuable information. Many
208 * applications tend not to use this, even though they should.
211 LogTag = _getprogname();
212 (void)fprintf(fp, "%s %d - - ",
213 LogTag == NULL ? "-" : LogTag, getpid());
215 /* Check to see if we can skip expanding the %m */
216 if (strstr(fmt, "%m")) {
218 /* Create the second stdio hook */
219 fmt_cookie.base = fmt_cpy;
220 fmt_cookie.left = sizeof(fmt_cpy) - 1;
221 fmt_fp = fwopen(&fmt_cookie, writehook);
222 if (fmt_fp == NULL) {
228 * Substitute error message for %m. Be careful not to
229 * molest an escaped percent "%%m". We want to pass it
230 * on untouched as the format is later parsed by vfprintf.
232 for ( ; (ch = *fmt); ++fmt) {
233 if (ch == '%' && fmt[1] == 'm') {
235 strerror_r(saved_errno, errstr, sizeof(errstr));
236 fputs(errstr, fmt_fp);
237 } else if (ch == '%' && fmt[1] == '%') {
246 /* Null terminate if room */
250 /* Guarantee null termination */
251 fmt_cpy[sizeof(fmt_cpy) - 1] = '\0';
256 (void)vfprintf(fp, fmt, ap);
259 cnt = sizeof(tbuf) - tbuf_cookie.left;
261 /* Remove a trailing newline */
262 if (tbuf[cnt - 1] == '\n')
265 /* Output to stderr if requested. */
266 if (LogStat & LOG_PERROR) {
268 struct iovec *v = iov;
271 v->iov_len = cnt - (stdp - tbuf);
275 (void)_writev(STDERR_FILENO, iov, 2);
278 /* Get connected, output the message to the local logger. */
280 openlog_unlocked(LogTag, LogStat | LOG_NDELAY, 0);
284 * If the send() fails, there are two likely scenarios:
285 * 1) syslogd was restarted
286 * 2) /var/run/log is out of socket buffer space, which
287 * in most cases means local DoS.
288 * If the error does not indicate a full buffer, we address
289 * case #1 by attempting to reconnect to /var/run/log[priv]
290 * and resending the message once.
292 * If we are working with a privileged socket, the retry
293 * attempts end there, because we don't want to freeze a
294 * critical application like su(1) or sshd(8).
296 * Otherwise, we address case #2 by repeatedly retrying the
297 * send() to give syslogd a chance to empty its socket buffer.
300 if (send(LogFile, tbuf, cnt, 0) < 0) {
301 if (errno != ENOBUFS) {
303 * Scenario 1: syslogd was restarted
304 * reconnect and resend once
308 if (send(LogFile, tbuf, cnt, 0) >= 0)
311 * if the resend failed, fall through to
312 * possible scenario 2
315 while (errno == ENOBUFS) {
317 * Scenario 2: out of socket buffer space
318 * possible DoS, fail fast on a privileged
321 if (status == CONNPRIV)
324 if (send(LogFile, tbuf, cnt, 0) >= 0)
331 * Output the message to the console; try not to block
332 * as a blocking console should not stop other processes.
333 * Make sure the error reported is the one from the syslogd failure.
335 if (LogStat & LOG_CONS &&
336 (fd = _open(_PATH_CONSOLE, O_WRONLY|O_NONBLOCK|O_CLOEXEC, 0)) >=
339 struct iovec *v = iov;
341 p = strchr(tbuf, '>') + 3;
343 v->iov_len = cnt - (p - tbuf);
345 v->iov_base = "\r\n";
347 (void)_writev(fd, iov, 2);
353 syslog_cancel_cleanup(void *arg __unused)
360 vsyslog(int pri, const char *fmt, va_list ap)
364 pthread_cleanup_push(syslog_cancel_cleanup, NULL);
365 vsyslog1(pri, fmt, ap);
366 pthread_cleanup_pop(1);
369 /* Should be called with mutex acquired */
374 * If the user closed the FD and opened another in the same slot,
375 * that's their problem. They should close it before calling on
382 status = NOCONN; /* retry connect */
385 /* Should be called with mutex acquired */
389 struct sockaddr_un SyslogAddr; /* AF_UNIX address of local logger */
392 if ((LogFile = _socket(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC,
396 if (LogFile != -1 && status == NOCONN) {
397 SyslogAddr.sun_len = sizeof(SyslogAddr);
398 SyslogAddr.sun_family = AF_UNIX;
401 * First try privileged socket. If no success,
402 * then try default socket.
404 (void)strncpy(SyslogAddr.sun_path, _PATH_LOG_PRIV,
405 sizeof SyslogAddr.sun_path);
406 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr,
407 sizeof(SyslogAddr)) != -1)
410 if (status == NOCONN) {
411 (void)strncpy(SyslogAddr.sun_path, _PATH_LOG,
412 sizeof SyslogAddr.sun_path);
413 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr,
414 sizeof(SyslogAddr)) != -1)
418 if (status == NOCONN) {
420 * Try the old "/dev/log" path, for backward
423 (void)strncpy(SyslogAddr.sun_path, _PATH_OLDLOG,
424 sizeof SyslogAddr.sun_path);
425 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr,
426 sizeof(SyslogAddr)) != -1)
430 if (status == NOCONN) {
431 (void)_close(LogFile);
438 openlog_unlocked(const char *ident, int logstat, int logfac)
443 if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
444 LogFacility = logfac;
446 if (LogStat & LOG_NDELAY) /* open immediately */
449 opened = 1; /* ident and facility has been set */
453 openlog(const char *ident, int logstat, int logfac)
457 pthread_cleanup_push(syslog_cancel_cleanup, NULL);
458 openlog_unlocked(ident, logstat, logfac);
459 pthread_cleanup_pop(1);
468 (void)_close(LogFile);
476 /* setlogmask -- set the log mask level */
478 setlogmask(int pmask)