NetBSD/lib/libc/gen/syslog.c

440 lines
11 KiB
C

/* $NetBSD: syslog.c,v 1.39 2006/11/22 17:23:25 christos Exp $ */
/*
* Copyright (c) 1983, 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)syslog.c 8.5 (Berkeley) 4/29/95";
#else
__RCSID("$NetBSD: syslog.c,v 1.39 2006/11/22 17:23:25 christos Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <netdb.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include "reentrant.h"
#include "extern.h"
#ifdef __weak_alias
__weak_alias(closelog,_closelog)
__weak_alias(openlog,_openlog)
__weak_alias(setlogmask,_setlogmask)
__weak_alias(syslog,_syslog)
__weak_alias(vsyslog,_vsyslog)
__weak_alias(closelog_r,_closelog_r)
__weak_alias(openlog_r,_openlog_r)
__weak_alias(setlogmask_r,_setlogmask_r)
__weak_alias(syslog_r,_syslog_r)
__weak_alias(vsyslog_r,_vsyslog_r)
__weak_alias(syslog_ss,_syslog_ss)
__weak_alias(vsyslog_ss,_vsyslog_ss)
#endif
static struct syslog_data sdata = SYSLOG_DATA_INIT;
static void openlog_unlocked_r(const char *, int, int,
struct syslog_data *);
static void disconnectlog_r(struct syslog_data *);
static void connectlog_r(struct syslog_data *);
#define LOG_SIGNAL_SAFE (int)0x80000000
#ifdef _REENTRANT
static mutex_t syslog_mutex = MUTEX_INITIALIZER;
#endif
/*
* syslog, vsyslog --
* print message on log file; output is intended for syslogd(8).
*/
void
syslog(int pri, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vsyslog(pri, fmt, ap);
va_end(ap);
}
void
vsyslog(int pri, const char *fmt, va_list ap)
{
vsyslog_r(pri, &sdata, fmt, ap);
}
void
openlog(const char *ident, int logstat, int logfac)
{
openlog_r(ident, logstat, logfac, &sdata);
}
void
closelog(void)
{
closelog_r(&sdata);
}
/* setlogmask -- set the log mask level */
int
setlogmask(int pmask)
{
return setlogmask_r(pmask, &sdata);
}
/* Reentrant version of syslog, i.e. syslog_r() */
void
syslog_r(int pri, struct syslog_data *data, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vsyslog_r(pri, data, fmt, ap);
va_end(ap);
}
void
syslog_ss(int pri, struct syslog_data *data, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vsyslog_r(pri | LOG_SIGNAL_SAFE, data, fmt, ap);
va_end(ap);
}
void
vsyslog_ss(int pri, struct syslog_data *data, const char *fmt, va_list ap)
{
vsyslog_r(pri | LOG_SIGNAL_SAFE, data, fmt, ap);
}
void
vsyslog_r(int pri, struct syslog_data *data, const char *fmt, va_list ap)
{
size_t cnt, prlen;
char ch, *p, *t;
time_t now;
struct tm tmnow;
int fd, saved_errno;
#define TBUF_LEN 2048
#define FMT_LEN 1024
char *stdp = NULL; /* pacify gcc */
char tbuf[TBUF_LEN], fmt_cpy[FMT_LEN];
size_t tbuf_left, fmt_left;
int signal_safe = pri & LOG_SIGNAL_SAFE;
pri &= ~LOG_SIGNAL_SAFE;
#define INTERNALLOG LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
/* Check for invalid bits. */
if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
syslog_r(INTERNALLOG | signal_safe, data,
"syslog_r: unknown facility/priority: %x", pri);
pri &= LOG_PRIMASK|LOG_FACMASK;
}
/* Check priority against setlogmask values. */
if (!(LOG_MASK(LOG_PRI(pri)) & data->log_mask))
return;
saved_errno = errno;
/* Set default facility if none specified. */
if ((pri & LOG_FACMASK) == 0)
pri |= data->log_fac;
/* Build the message. */
/*
* Although it's tempting, we can't ignore the possibility of
* overflowing the buffer when assembling the "fixed" portion
* of the message. Strftime's "%h" directive expands to the
* locale's abbreviated month name, but if the user has the
* ability to construct to his own locale files, it may be
* arbitrarily long.
*/
if (!signal_safe)
(void)time(&now);
p = tbuf;
tbuf_left = TBUF_LEN;
#define DEC() \
do { \
if (prlen >= tbuf_left) \
prlen = tbuf_left - 1; \
p += prlen; \
tbuf_left -= prlen; \
} while (/*CONSTCOND*/0)
prlen = snprintf_ss(p, tbuf_left, "<%d>", pri);
DEC();
if (!signal_safe) {
/* strftime() implies tzset(), localtime_r() doesn't. */
tzset();
prlen = strftime(p, tbuf_left, "%h %e %T ",
localtime_r(&now, &tmnow));
DEC();
}
if (data->log_stat & LOG_PERROR)
stdp = p;
if (data->log_tag == NULL)
data->log_tag = getprogname();
if (data->log_tag != NULL) {
prlen = snprintf_ss(p, tbuf_left, "%s", data->log_tag);
DEC();
}
if (data->log_stat & LOG_PID) {
prlen = snprintf_ss(p, tbuf_left, "[%d]", getpid());
DEC();
}
if (data->log_tag != NULL) {
if (tbuf_left > 1) {
*p++ = ':';
tbuf_left--;
}
if (tbuf_left > 1) {
*p++ = ' ';
tbuf_left--;
}
}
/*
* We wouldn't need this mess if printf handled %m, or if
* strerror() had been invented before syslog().
*/
for (t = fmt_cpy, fmt_left = FMT_LEN; (ch = *fmt) != '\0'; ++fmt) {
if (ch == '%' && fmt[1] == 'm') {
char ebuf[128];
++fmt;
if (signal_safe ||
strerror_r(saved_errno, ebuf, sizeof(ebuf)))
prlen = snprintf_ss(t, fmt_left, "Error %d",
saved_errno);
else
prlen = snprintf_ss(t, fmt_left, "%s", ebuf);
if (prlen >= fmt_left)
prlen = fmt_left - 1;
t += prlen;
fmt_left -= prlen;
} else if (ch == '%' && fmt[1] == '%' && fmt_left > 2) {
*t++ = '%';
*t++ = '%';
fmt++;
fmt_left -= 2;
} else {
if (fmt_left > 1) {
*t++ = ch;
fmt_left--;
}
}
}
*t = '\0';
if (signal_safe)
prlen = vsnprintf_ss(p, tbuf_left, fmt_cpy, ap);
else
prlen = vsnprintf(p, tbuf_left, fmt_cpy, ap);
DEC();
cnt = p - tbuf;
/* Output to stderr if requested. */
if (data->log_stat & LOG_PERROR) {
struct iovec iov[2];
iov[0].iov_base = stdp;
iov[0].iov_len = cnt - (stdp - tbuf);
iov[1].iov_base = __UNCONST("\n");
iov[1].iov_len = 1;
(void)writev(STDERR_FILENO, iov, 2);
}
/* Get connected, output the message to the local logger. */
if (data == &sdata)
mutex_lock(&syslog_mutex);
if (!data->opened)
openlog_unlocked_r(data->log_tag, data->log_stat, 0, data);
connectlog_r(data);
/*
* If the send() failed, there are two likely scenarios:
* 1) syslogd was restarted
* 2) /dev/log is out of socket buffer space
* We attempt to reconnect to /dev/log to take care of
* case #1 and keep send()ing data to cover case #2
* to give syslogd a chance to empty its socket buffer.
*/
if (send(data->log_file, tbuf, cnt, 0) == -1) {
if (errno != ENOBUFS) {
disconnectlog_r(data);
connectlog_r(data);
}
do {
usleep(1);
if (send(data->log_file, tbuf, cnt, 0) != -1)
break;
} while (errno == ENOBUFS);
}
if (data == &sdata)
mutex_unlock(&syslog_mutex);
/*
* Output the message to the console; try not to block
* as a blocking console should not stop other processes.
* Make sure the error reported is the one from the syslogd failure.
*/
if ((data->log_stat & LOG_CONS) &&
(fd = open(_PATH_CONSOLE, O_WRONLY|O_NONBLOCK, 0)) >= 0) {
struct iovec iov[2];
p = strchr(tbuf, '>') + 1;
iov[0].iov_base = p;
iov[0].iov_len = cnt - (p - tbuf);
iov[1].iov_base = __UNCONST("\r\n");
iov[1].iov_len = 2;
(void)writev(fd, iov, 2);
(void)close(fd);
}
if (data != &sdata)
closelog_r(data);
}
static void
disconnectlog_r(struct syslog_data *data)
{
/*
* If the user closed the FD and opened another in the same slot,
* that's their problem. They should close it before calling on
* system services.
*/
if (data->log_file != -1) {
(void)close(data->log_file);
data->log_file = -1;
}
data->connected = 0; /* retry connect */
}
static void
connectlog_r(struct syslog_data *data)
{
/* AF_UNIX address of local logger */
static const struct sockaddr_un sun = {
.sun_family = AF_LOCAL,
.sun_len = sizeof(sun),
.sun_path = _PATH_LOG,
};
if (data->log_file == -1 || fcntl(data->log_file, F_GETFL, 0) == -1) {
if ((data->log_file = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1)
return;
(void)fcntl(data->log_file, F_SETFD, FD_CLOEXEC);
data->connected = 0;
}
if (!data->connected) {
if (connect(data->log_file,
(const struct sockaddr *)(const void *)&sun,
sizeof(sun)) == -1) {
(void)close(data->log_file);
data->log_file = -1;
} else
data->connected = 1;
}
}
static void
openlog_unlocked_r(const char *ident, int logstat, int logfac,
struct syslog_data *data)
{
if (ident != NULL)
data->log_tag = ident;
data->log_stat = logstat;
if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
data->log_fac = logfac;
if (data->log_stat & LOG_NDELAY) /* open immediately */
connectlog_r(data);
}
void
openlog_r(const char *ident, int logstat, int logfac, struct syslog_data *data)
{
if (data == &sdata)
mutex_lock(&syslog_mutex);
openlog_unlocked_r(ident, logstat, logfac, data);
if (data == &sdata)
mutex_unlock(&syslog_mutex);
}
void
closelog_r(struct syslog_data *data)
{
if (data == &sdata)
mutex_lock(&syslog_mutex);
(void)close(data->log_file);
data->log_file = -1;
data->connected = 0;
data->log_tag = NULL;
if (data == &sdata)
mutex_unlock(&syslog_mutex);
}
int
setlogmask_r(int pmask, struct syslog_data *data)
{
int omask;
omask = data->log_mask;
if (pmask != 0)
data->log_mask = pmask;
return omask;
}