/* $OpenBSD: syslog.c,v 1.28 2005/08/08 08:05:34 espie 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/types.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <syslog.h>
#include <sys/un.h>
#include <netdb.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <stdarg.h>
static struct syslog_data sdata = SYSLOG_DATA_INIT;
extern const char *__progname; /* Program name, from crt0. */
static void disconnectlog_r(struct syslog_data *); /* disconnect from syslogd */
static void connectlog_r(struct syslog_data *); /* (re)connect to syslogd */
/*
* 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
vsyslog_r(int pri, struct syslog_data *data, const char *fmt, va_list ap)
{
int cnt;
char ch, *p, *t;
time_t now;
int fd, saved_errno, error;
#define TBUF_LEN 2048
#define FMT_LEN 1024
char *stdp = NULL, tbuf[TBUF_LEN], fmt_cpy[FMT_LEN];
int tbuf_left, fmt_left, prlen;
#define INTERNALLOG LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
/* Check for invalid bits. */
if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
if (data == &sdata) {
syslog(INTERNALLOG,
"syslog: unknown facility/priority: %x", pri);
} else {
syslog_r(INTERNALLOG, 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;
/* If we have been called through syslog(), no need for reentrancy. */
if (data == &sdata)
(void)time(&now);
p = tbuf;
tbuf_left = TBUF_LEN;
#define DEC() \
do { \
if (prlen < 0) \
prlen = 0; \
if (prlen >= tbuf_left) \
prlen = tbuf_left - 1; \
p += prlen; \
tbuf_left -= prlen; \
} while (0)
prlen = snprintf(p, tbuf_left, "<%d>", pri);
DEC();
/*
* syslogd will expand time automagically for reentrant case, and
* for normal case, just do like before
*/
if (data == &sdata) {
prlen = strftime(p, tbuf_left, "%h %e %T ", localtime(&now));
DEC();
}
if (data->log_stat & LOG_PERROR)
stdp = p;
if (data->log_tag == NULL)
data->log_tag = __progname;
if (data->log_tag != NULL) {
prlen = snprintf(p, tbuf_left, "%s", data->log_tag);
DEC();
}
if (data->log_stat & LOG_PID) {
prlen = snprintf(p, tbuf_left, "[%ld]", (long)getpid());
DEC();
}
if (data->log_tag != NULL) {
if (tbuf_left > 1) {
*p++ = ':';
tbuf_left--;
}
if (tbuf_left > 1) {
*p++ = ' ';
tbuf_left--;
}
}
/* strerror() is not reentrant */
for (t = fmt_cpy, fmt_left = FMT_LEN; (ch = *fmt); ++fmt) {
if (ch == '%' && fmt[1] == 'm') {
++fmt;
if (data == &sdata) {
prlen = snprintf(t, fmt_left, "%s",
strerror(saved_errno));
} else {
prlen = snprintf(t, fmt_left, "Error %d",
saved_errno);
}
if (prlen < 0)
prlen = 0;
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';
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 = "\n";
iov[1].iov_len = 1;
(void)writev(STDERR_FILENO, iov, 2);
}
/* Get connected, output the message to the local logger. */
if (!data->opened)
openlog_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 ((error = send(data->log_file, tbuf, cnt, 0)) < 0) {
if (errno != ENOBUFS) {
disconnectlog_r(data);
connectlog_r(data);
}
do {
usleep(1);
if ((error = send(data->log_file, tbuf, cnt, 0)) >= 0)
break;
} while (errno == ENOBUFS);
}
/*
* 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 (error == -1 && (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 = "\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) {
close(data->log_file);
data->log_file = -1;
}
data->connected = 0; /* retry connect */
}
static void
connectlog_r(struct syslog_data *data)
{
union {
struct sockaddr syslogAddr;
struct sockaddr_un syslogAddrUn;
} u;
#define SyslogAddr u.syslogAddrUn
if (data->log_file == -1) {
if ((data->log_file = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1)
return;
(void)fcntl(data->log_file, F_SETFD, 1);
}
if (data->log_file != -1 && !data->connected) {
memset(&SyslogAddr, '\0', sizeof(SyslogAddr));
#if 0
/* BIONIC: no sun_len field to fill on Linux */
SyslogAddr.sun_len = sizeof(SyslogAddr);
#endif
SyslogAddr.sun_family = AF_UNIX;
strlcpy(SyslogAddr.sun_path, _PATH_LOG,
sizeof(SyslogAddr.sun_path));
if (connect(data->log_file, &u.syslogAddr,
sizeof(SyslogAddr)) == -1) {
(void)close(data->log_file);
data->log_file = -1;
} else
data->connected = 1;
}
}
void
openlog_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);
data->opened = 1; /* ident and facility has been set */
}
void
closelog_r(struct syslog_data *data)
{
(void)close(data->log_file);
data->log_file = -1;
data->connected = 0;
data->log_tag = NULL;
}
/* setlogmask -- set the log mask level */
int
setlogmask_r(int pmask, struct syslog_data *data)
{
int omask;
omask = data->log_mask;
if (pmask != 0)
data->log_mask = pmask;
return (omask);
}