freebsd-dev/lib/libc/gen/syslog.c
Peter Wemm 7e6ace8561 If the send() to the AF_UNIX socket to the syslogd fails, attempt to
reconnect once using the saved openlog() parameters.

This helps one of the system startup race conditions. If syslogd takes too
long to get going, some daemons can fail the connection and forever log
to the console even though the syslogd is running.  That is ..unfortunate..
1996-03-02 19:56:16 +00:00

351 lines
8.5 KiB
C

/*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
/*
static char sccsid[] = "From: @(#)syslog.c 8.4 (Berkeley) 3/18/94";
*/
static const char rcsid[] =
"$Id: syslog.c,v 1.7 1995/10/22 14:37:08 phk Exp $";
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <sys/uio.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>
#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif
static int LogFile = -1; /* fd for log */
static int connected; /* have done connect */
static int opened; /* have done openlog() */
static int LogStat = 0; /* status bits, set by openlog() */
static const char *LogTag = NULL; /* string to tag the entry with */
static int LogFacility = LOG_USER; /* default facility code */
static int LogMask = 0xff; /* mask of priorities to be logged */
extern char *__progname; /* Program name, from crt0. */
static void disconnectlog __P((void)); /* disconnect from syslogd */
static void connectlog __P((void)); /* (re)connect to syslogd */
/*
* Format of the magic cookie passed through the stdio hook
*/
struct bufcookie {
char *base; /* start of buffer */
int left;
};
/*
* stdio write hook for writing to a static string buffer
* XXX: Maybe one day, dynamically allocate it so that the line length
* is `unlimited'.
*/
static
int writehook(cookie, buf, len)
void *cookie; /* really [struct bufcookie *] */
char *buf; /* characters to copy */
int len; /* length to copy */
{
struct bufcookie *h; /* private `handle' */
h = (struct bufcookie *)cookie;
if (len > h->left) {
/* clip in case of wraparound */
len = h->left;
}
if (len > 0) {
(void)memcpy(h->base, buf, len); /* `write' it. */
h->base += len;
h->left -= len;
}
return 0;
}
/*
* syslog, vsyslog --
* print message on log file; output is intended for syslogd(8).
*/
void
#if __STDC__
syslog(int pri, const char *fmt, ...)
#else
syslog(pri, fmt, va_alist)
int pri;
char *fmt;
va_dcl
#endif
{
va_list ap;
#if __STDC__
va_start(ap, fmt);
#else
va_start(ap);
#endif
vsyslog(pri, fmt, ap);
va_end(ap);
}
void
vsyslog(pri, fmt, ap)
int pri;
register const char *fmt;
va_list ap;
{
register int cnt;
register char ch, *p;
time_t now;
int fd, saved_errno;
char *stdp, tbuf[2048], fmt_cpy[1024];
FILE *fp, *fmt_fp;
struct bufcookie tbuf_cookie;
struct bufcookie fmt_cookie;
#define INTERNALLOG LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
/* Check for invalid bits. */
if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
syslog(INTERNALLOG,
"syslog: unknown facility/priority: %x", pri);
pri &= LOG_PRIMASK|LOG_FACMASK;
}
/* Check priority against setlogmask values. */
if (!(LOG_MASK(LOG_PRI(pri)) & LogMask))
return;
saved_errno = errno;
/* Set default facility if none specified. */
if ((pri & LOG_FACMASK) == 0)
pri |= LogFacility;
/* Create the primary stdio hook */
tbuf_cookie.base = tbuf;
tbuf_cookie.left = sizeof(tbuf);
fp = fwopen(&tbuf_cookie, writehook);
if (fp == NULL)
return;
/* Build the message. */
(void)time(&now);
(void)fprintf(fp, "<%d>", pri);
(void)fprintf(fp, "%.15s ", ctime(&now) + 4);
if (LogStat & LOG_PERROR) {
/* Transfer to string buffer */
(void)fflush(fp);
stdp = tbuf + (sizeof(tbuf) - tbuf_cookie.left);
}
if (LogTag == NULL)
LogTag = __progname;
if (LogTag != NULL)
(void)fprintf(fp, "%s", LogTag);
if (LogStat & LOG_PID)
(void)fprintf(fp, "[%d]", getpid());
if (LogTag != NULL) {
(void)fprintf(fp, ": ");
}
/* Check to see if we can skip expanding the %m */
if (strstr(fmt, "%m")) {
/* Create the second stdio hook */
fmt_cookie.base = fmt_cpy;
fmt_cookie.left = sizeof(fmt_cpy) - 1;
fmt_fp = fwopen(&fmt_cookie, writehook);
if (fmt_fp == NULL) {
fclose(fp);
return;
}
/* Substitute error message for %m. */
for ( ; ch = *fmt; ++fmt)
if (ch == '%' && fmt[1] == 'm') {
++fmt;
fputs(strerror(saved_errno), fmt_fp);
} else
fputc(ch, fmt_fp);
/* Null terminate if room */
fputc(0, fmt_fp);
fclose(fmt_fp);
/* Guarantee null termination */
fmt_cpy[sizeof(fmt_cpy) - 1] = '\0';
fmt = fmt_cpy;
}
(void)vfprintf(fp, fmt, ap);
(void)fclose(fp);
cnt = sizeof(tbuf) - tbuf_cookie.left;
/* Output to stderr if requested. */
if (LogStat & LOG_PERROR) {
struct iovec iov[2];
register struct iovec *v = iov;
v->iov_base = stdp;
v->iov_len = cnt - (stdp - tbuf);
++v;
v->iov_base = "\n";
v->iov_len = 1;
(void)writev(STDERR_FILENO, iov, 2);
}
/* Get connected, output the message to the local logger. */
if (!opened)
openlog(LogTag, LogStat | LOG_NDELAY, 0);
connectlog();
if (send(LogFile, tbuf, cnt, 0) >= 0)
return;
/*
* If the send() failed, the odds are syslogd was restarted.
* Make one (only) attempt to reconnect to /dev/log.
*/
disconnectlog();
connectlog();
if (send(LogFile, tbuf, cnt, 0) >= 0)
return;
/*
* Output the message to the console; don't worry about blocking,
* if console blocks everything will. Make sure the error reported
* is the one from the syslogd failure.
*/
if (LogStat & LOG_CONS &&
(fd = open(_PATH_CONSOLE, O_WRONLY, 0)) >= 0) {
struct iovec iov[2];
register struct iovec *v = iov;
p = strchr(tbuf, '>') + 1;
v->iov_base = p;
v->iov_len = cnt - (p - tbuf);
++v;
v->iov_base = "\r\n";
v->iov_len = 2;
(void)writev(fd, iov, 2);
(void)close(fd);
}
}
static struct sockaddr SyslogAddr; /* AF_UNIX address of local logger */
static void
disconnectlog()
{
/*
* 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 (LogFile != -1) {
close(LogFile);
LogFile = -1;
}
connected = 0; /* retry connect */
}
static void
connectlog()
{
if (LogFile == -1) {
SyslogAddr.sa_family = AF_UNIX;
(void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
sizeof(SyslogAddr.sa_data));
if ((LogFile = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1)
return;
(void)fcntl(LogFile, F_SETFD, 1);
}
if (LogFile != -1 && !connected) {
if (connect(LogFile, &SyslogAddr, sizeof(SyslogAddr)) == -1) {
(void)close(LogFile);
LogFile = -1;
} else
connected = 1;
}
}
void
openlog(ident, logstat, logfac)
const char *ident;
int logstat, logfac;
{
if (ident != NULL)
LogTag = ident;
LogStat = logstat;
if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
LogFacility = logfac;
if (LogStat & LOG_NDELAY) /* open immediately */
connectlog();
opened = 1; /* ident and facility has been set */
}
void
closelog()
{
(void)close(LogFile);
LogFile = -1;
connected = 0;
}
/* setlogmask -- set the log mask level */
int
setlogmask(pmask)
int pmask;
{
int omask;
omask = LogMask;
if (pmask != 0)
LogMask = pmask;
return (omask);
}