syslog_r.c revision 1.15 
1/*	$OpenBSD: syslog_r.c,v 1.15 2016/03/27 16:28:56 chl Exp $ */
2/*
3 * Copyright (c) 1983, 1988, 1993
4 *	The Regents of the University of California.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <sys/types.h>
32#include <sys/uio.h>
33#include <netdb.h>
34
35#include <errno.h>
36#include <fcntl.h>
37#include <paths.h>
38#include <stdio.h>
39#include <stdlib.h>
40#include <string.h>
41#include <syslog.h>
42#include <time.h>
43#include <unistd.h>
44#include <limits.h>
45#include <stdarg.h>
46
47/* Reentrant version of syslog, i.e. syslog_r() */
48void
49syslog_r(int pri, struct syslog_data *data, const char *fmt, ...)
50{
51	va_list ap;
52
53	va_start(ap, fmt);
54	vsyslog_r(pri, data, fmt, ap);
55	va_end(ap);
56}
57DEF_WEAK(syslog_r);
58
59void
60vsyslog_r(int pri, struct syslog_data *data, const char *fmt, va_list ap)
61{
62	__vsyslog_r(pri, data, 1, fmt, ap);
63}
64DEF_WEAK(vsyslog_r);
65
66/*
67 * This is used by both syslog_r and syslog.
68 */
69void
70__vsyslog_r(int pri, struct syslog_data *data,
71    int reentrant, const char *fmt, va_list ap)
72{
73	int cnt;
74	char ch, *p, *t;
75	int saved_errno;
76#define	TBUF_LEN	(8192+1)
77#define	FMT_LEN		1024
78	char *conp = NULL, *stdp = NULL, tbuf[TBUF_LEN], fmt_cpy[FMT_LEN];
79	int tbuf_left, fmt_left, prlen;
80
81#define	INTERNALLOG	LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
82	/* Check for invalid bits. */
83	if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
84		syslog_r(INTERNALLOG, data,
85		    "syslog%s: unknown facility/priority: %x",
86		    reentrant ? "_r" : "", pri);
87		pri &= LOG_PRIMASK|LOG_FACMASK;
88	}
89
90	/* Check priority against setlogmask values. */
91	if (!(LOG_MASK(LOG_PRI(pri)) & data->log_mask))
92		return;
93
94	saved_errno = errno;
95
96	/* Set default facility if none specified. */
97	if ((pri & LOG_FACMASK) == 0)
98		pri |= data->log_fac;
99
100	p = tbuf;
101	tbuf_left = TBUF_LEN;
102
103#define	DEC()	\
104	do {					\
105		if (prlen < 0)			\
106			prlen = 0;		\
107		if (prlen >= tbuf_left)		\
108			prlen = tbuf_left - 1;	\
109		p += prlen;			\
110		tbuf_left -= prlen;		\
111	} while (0)
112
113	prlen = snprintf(p, tbuf_left, "<%d>", pri);
114	DEC();
115	if (data->log_stat & LOG_CONS)
116		conp = p;
117
118	if (data->log_stat & LOG_PERROR)
119		stdp = p;
120	if (data->log_tag == NULL)
121		data->log_tag = __progname;
122	if (data->log_tag != NULL) {
123		prlen = snprintf(p, tbuf_left, "%.*s", NAME_MAX, data->log_tag);
124		DEC();
125	}
126	if (data->log_stat & LOG_PID) {
127		prlen = snprintf(p, tbuf_left, "[%ld]", (long)getpid());
128		DEC();
129	}
130	if (data->log_tag != NULL) {
131		if (tbuf_left > 1) {
132			*p++ = ':';
133			tbuf_left--;
134		}
135		if (tbuf_left > 1) {
136			*p++ = ' ';
137			tbuf_left--;
138		}
139	}
140
141	/* strerror() is not reentrant */
142
143	for (t = fmt_cpy, fmt_left = FMT_LEN; (ch = *fmt); ++fmt) {
144		if (ch == '%' && fmt[1] == 'm') {
145			++fmt;
146			if (reentrant) {
147				prlen = snprintf(t, fmt_left, "Error %d",
148				    saved_errno);
149			} else {
150				prlen = snprintf(t, fmt_left, "%s",
151				    strerror(saved_errno));
152			}
153			if (prlen < 0)
154				prlen = 0;
155			if (prlen >= fmt_left)
156				prlen = fmt_left - 1;
157			t += prlen;
158			fmt_left -= prlen;
159		} else if (ch == '%' && fmt[1] == '%' && fmt_left > 2) {
160			*t++ = '%';
161			*t++ = '%';
162			fmt++;
163			fmt_left -= 2;
164		} else {
165			if (fmt_left > 1) {
166				*t++ = ch;
167				fmt_left--;
168			}
169		}
170	}
171	*t = '\0';
172
173	prlen = vsnprintf(p, tbuf_left, fmt_cpy, ap);
174	DEC();
175	cnt = p - tbuf;
176	while (cnt > 0 && p[-1] == '\n') {
177		*(--p) = '\0';
178		--cnt;
179	}
180
181	/* Output to stderr if requested. */
182	if (data->log_stat & LOG_PERROR) {
183		struct iovec iov[2];
184
185		iov[0].iov_base = stdp;
186		iov[0].iov_len = cnt > stdp - tbuf ? cnt - (stdp - tbuf) : 0;
187		iov[1].iov_base = "\n";
188		iov[1].iov_len = 1;
189		(void)writev(STDERR_FILENO, iov, 2);
190	}
191
192	/*
193	 * If the sendsyslog() fails, it means that syslogd
194	 * is not running or the kernel ran out of buffers.
195	 */
196	sendsyslog(tbuf, cnt, data->log_stat & LOG_CONS);
197}
198
199void
200openlog_r(const char *ident, int logstat, int logfac, struct syslog_data *data)
201{
202	if (ident != NULL)
203		data->log_tag = ident;
204	data->log_stat = logstat;
205	if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
206		data->log_fac = logfac;
207}
208DEF_WEAK(openlog_r);
209
210void
211closelog_r(struct syslog_data *data)
212{
213	data->log_tag = NULL;
214}
215DEF_WEAK(closelog_r);
216