Do not cache PID for a process that does not fabricate it,
calls openlog() before forking and does not call exec() thereafter.
PR: 268666
Fixes: e9ae9fa937
Tested by: kp
MFC after: 3 days
501 lines
12 KiB
C
501 lines
12 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1983, 1988, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__SCCSID("@(#)syslog.c 8.5 (Berkeley) 4/29/95");
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__FBSDID("$FreeBSD$");
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#include "namespace.h"
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <sys/syslog.h>
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#include <sys/time.h>
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#include <sys/uio.h>
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#include <sys/un.h>
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#include <netdb.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <paths.h>
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#include <pthread.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include <stdarg.h>
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#include "un-namespace.h"
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#include "libc_private.h"
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/* Maximum number of characters of syslog message */
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#define MAXLINE 8192
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static int LogFile = -1; /* fd for log */
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static bool connected; /* have done connect */
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static int opened; /* have done openlog() */
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static int LogStat = 0; /* status bits, set by openlog() */
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static pid_t LogPid = -1; /* process id to tag the entry with */
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static const char *LogTag = NULL; /* string to tag the entry with */
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static int LogTagLength = -1; /* usable part of LogTag */
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static int LogFacility = LOG_USER; /* default facility code */
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static int LogMask = 0xff; /* mask of priorities to be logged */
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static pthread_mutex_t syslog_mutex = PTHREAD_MUTEX_INITIALIZER;
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#define THREAD_LOCK() \
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do { \
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if (__isthreaded) _pthread_mutex_lock(&syslog_mutex); \
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} while(0)
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#define THREAD_UNLOCK() \
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do { \
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if (__isthreaded) _pthread_mutex_unlock(&syslog_mutex); \
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} while(0)
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/* RFC5424 defined value. */
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#define NILVALUE "-"
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static void disconnectlog(void); /* disconnect from syslogd */
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static void connectlog(void); /* (re)connect to syslogd */
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static void openlog_unlocked(const char *, int, int);
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static void parse_tag(void); /* parse ident[NNN] if needed */
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/*
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* Format of the magic cookie passed through the stdio hook
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*/
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struct bufcookie {
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char *base; /* start of buffer */
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int left;
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};
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/*
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* stdio write hook for writing to a static string buffer
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* XXX: Maybe one day, dynamically allocate it so that the line length
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* is `unlimited'.
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*/
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static int
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writehook(void *cookie, const char *buf, int len)
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{
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struct bufcookie *h; /* private `handle' */
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h = (struct bufcookie *)cookie;
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if (len > h->left) {
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/* clip in case of wraparound */
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len = h->left;
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}
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if (len > 0) {
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(void)memcpy(h->base, buf, len); /* `write' it. */
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h->base += len;
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h->left -= len;
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}
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return len;
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}
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/*
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* syslog, vsyslog --
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* print message on log file; output is intended for syslogd(8).
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*/
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void
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syslog(int pri, const char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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vsyslog(pri, fmt, ap);
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va_end(ap);
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}
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static void
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vsyslog1(int pri, const char *fmt, va_list ap)
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{
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struct timeval now;
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struct tm tm;
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char ch, *p;
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long tz_offset;
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int cnt, fd, saved_errno;
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char hostname[MAXHOSTNAMELEN], *stdp, tbuf[MAXLINE], fmt_cpy[MAXLINE],
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errstr[64], tz_sign;
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FILE *fp, *fmt_fp;
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struct bufcookie tbuf_cookie;
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struct bufcookie fmt_cookie;
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#define INTERNALLOG LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
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/* Check for invalid bits. */
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if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
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syslog(INTERNALLOG,
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"syslog: unknown facility/priority: %x", pri);
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pri &= LOG_PRIMASK|LOG_FACMASK;
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}
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saved_errno = errno;
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/* Check priority against setlogmask values. */
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if (!(LOG_MASK(LOG_PRI(pri)) & LogMask))
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return;
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/* Set default facility if none specified. */
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if ((pri & LOG_FACMASK) == 0)
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pri |= LogFacility;
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/* Create the primary stdio hook */
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tbuf_cookie.base = tbuf;
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tbuf_cookie.left = sizeof(tbuf);
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fp = fwopen(&tbuf_cookie, writehook);
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if (fp == NULL)
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return;
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/* Build the message according to RFC 5424. Tag and version. */
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(void)fprintf(fp, "<%d>1 ", pri);
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/* Timestamp similar to RFC 3339. */
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if (gettimeofday(&now, NULL) == 0 &&
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localtime_r(&now.tv_sec, &tm) != NULL) {
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if (tm.tm_gmtoff < 0) {
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tz_sign = '-';
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tz_offset = -tm.tm_gmtoff;
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} else {
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tz_sign = '+';
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tz_offset = tm.tm_gmtoff;
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}
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(void)fprintf(fp,
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"%04d-%02d-%02d" /* Date. */
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"T%02d:%02d:%02d.%06ld" /* Time. */
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"%c%02ld:%02ld ", /* Time zone offset. */
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tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
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tm.tm_hour, tm.tm_min, tm.tm_sec, now.tv_usec,
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tz_sign, tz_offset / 3600, (tz_offset % 3600) / 60);
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} else
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(void)fputs(NILVALUE " ", fp);
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/* Hostname. */
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(void)gethostname(hostname, sizeof(hostname));
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(void)fprintf(fp, "%s ",
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hostname[0] == '\0' ? NILVALUE : hostname);
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if (LogStat & LOG_PERROR) {
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/* Transfer to string buffer */
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(void)fflush(fp);
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stdp = tbuf + (sizeof(tbuf) - tbuf_cookie.left);
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}
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/* Application name. */
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if (LogTag == NULL)
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LogTag = _getprogname();
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else if (LogTagLength == -1)
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parse_tag();
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if (LogTagLength > 0)
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(void)fprintf(fp, "%.*s ", LogTagLength, LogTag);
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else
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(void)fprintf(fp, "%s ", LogTag == NULL ? NILVALUE : LogTag);
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/*
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* Provide the process ID regardless of whether LOG_PID has been
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* specified, as it provides valuable information. Many
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* applications tend not to use this, even though they should.
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*/
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if (LogTagLength <= 0)
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LogPid = getpid();
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(void)fprintf(fp, "%d ", (int)LogPid);
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/* Message ID. */
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(void)fputs(NILVALUE " ", fp);
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/* Structured data. */
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(void)fputs(NILVALUE " ", fp);
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/* Check to see if we can skip expanding the %m */
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if (strstr(fmt, "%m")) {
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/* Create the second stdio hook */
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fmt_cookie.base = fmt_cpy;
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fmt_cookie.left = sizeof(fmt_cpy) - 1;
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fmt_fp = fwopen(&fmt_cookie, writehook);
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if (fmt_fp == NULL) {
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fclose(fp);
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return;
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}
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/*
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* Substitute error message for %m. Be careful not to
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* molest an escaped percent "%%m". We want to pass it
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* on untouched as the format is later parsed by vfprintf.
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*/
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for ( ; (ch = *fmt); ++fmt) {
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if (ch == '%' && fmt[1] == 'm') {
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++fmt;
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strerror_r(saved_errno, errstr, sizeof(errstr));
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fputs(errstr, fmt_fp);
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} else if (ch == '%' && fmt[1] == '%') {
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++fmt;
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fputc(ch, fmt_fp);
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fputc(ch, fmt_fp);
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} else {
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fputc(ch, fmt_fp);
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}
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}
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/* Null terminate if room */
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fputc(0, fmt_fp);
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fclose(fmt_fp);
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/* Guarantee null termination */
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fmt_cpy[sizeof(fmt_cpy) - 1] = '\0';
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fmt = fmt_cpy;
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}
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/* Message. */
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(void)vfprintf(fp, fmt, ap);
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(void)fclose(fp);
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cnt = sizeof(tbuf) - tbuf_cookie.left;
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/* Remove a trailing newline */
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if (tbuf[cnt - 1] == '\n')
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cnt--;
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/* Output to stderr if requested. */
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if (LogStat & LOG_PERROR) {
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struct iovec iov[2];
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struct iovec *v = iov;
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v->iov_base = stdp;
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v->iov_len = cnt - (stdp - tbuf);
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++v;
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v->iov_base = "\n";
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v->iov_len = 1;
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(void)_writev(STDERR_FILENO, iov, 2);
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}
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/* Get connected, output the message to the local logger. */
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if (!opened)
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openlog_unlocked(LogTag, LogStat | LOG_NDELAY, 0);
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connectlog();
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/*
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* If the send() failed, there are two likely scenarios:
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* 1) syslogd was restarted. In this case make one (only) attempt
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* to reconnect.
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* 2) We filled our buffer due to syslogd not being able to read
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* as fast as we write. In this case prefer to lose the current
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* message rather than whole buffer of previously logged data.
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*/
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if (send(LogFile, tbuf, cnt, 0) < 0) {
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if (errno != ENOBUFS) {
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disconnectlog();
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connectlog();
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if (send(LogFile, tbuf, cnt, 0) >= 0)
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return;
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}
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} else
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return;
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/*
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* Output the message to the console; try not to block
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* as a blocking console should not stop other processes.
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* Make sure the error reported is the one from the syslogd failure.
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*/
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if (LogStat & LOG_CONS &&
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(fd = _open(_PATH_CONSOLE, O_WRONLY|O_NONBLOCK|O_CLOEXEC, 0)) >=
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0) {
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struct iovec iov[2];
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struct iovec *v = iov;
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p = strchr(tbuf, '>') + 3;
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v->iov_base = p;
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v->iov_len = cnt - (p - tbuf);
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++v;
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v->iov_base = "\r\n";
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v->iov_len = 2;
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(void)_writev(fd, iov, 2);
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(void)_close(fd);
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}
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}
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static void
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syslog_cancel_cleanup(void *arg __unused)
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{
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THREAD_UNLOCK();
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}
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void
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vsyslog(int pri, const char *fmt, va_list ap)
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{
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THREAD_LOCK();
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pthread_cleanup_push(syslog_cancel_cleanup, NULL);
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vsyslog1(pri, fmt, ap);
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pthread_cleanup_pop(1);
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}
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/* Should be called with mutex acquired */
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static void
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disconnectlog(void)
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{
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/*
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* If the user closed the FD and opened another in the same slot,
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* that's their problem. They should close it before calling on
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* system services.
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*/
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if (LogFile != -1) {
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_close(LogFile);
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LogFile = -1;
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}
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connected = false; /* retry connect */
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}
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/* Should be called with mutex acquired */
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static void
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connectlog(void)
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{
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struct sockaddr_un SyslogAddr; /* AF_UNIX address of local logger */
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if (LogFile == -1) {
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socklen_t len;
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if ((LogFile = _socket(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC,
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0)) == -1)
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return;
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if (_getsockopt(LogFile, SOL_SOCKET, SO_SNDBUF, &len,
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&(socklen_t){sizeof(len)}) == 0) {
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if (len < MAXLINE) {
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len = MAXLINE;
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(void)_setsockopt(LogFile, SOL_SOCKET, SO_SNDBUF,
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&len, sizeof(len));
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}
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}
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}
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if (!connected) {
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SyslogAddr.sun_len = sizeof(SyslogAddr);
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SyslogAddr.sun_family = AF_UNIX;
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(void)strncpy(SyslogAddr.sun_path, _PATH_LOG,
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sizeof SyslogAddr.sun_path);
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if (_connect(LogFile, (struct sockaddr *)&SyslogAddr,
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sizeof(SyslogAddr)) != -1)
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connected = true;
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else {
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(void)_close(LogFile);
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LogFile = -1;
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}
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}
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}
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static void
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openlog_unlocked(const char *ident, int logstat, int logfac)
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{
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if (ident != NULL) {
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LogTag = ident;
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LogTagLength = -1;
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}
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LogStat = logstat;
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parse_tag();
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if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
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LogFacility = logfac;
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if (LogStat & LOG_NDELAY) /* open immediately */
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connectlog();
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opened = 1; /* ident and facility has been set */
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}
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void
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openlog(const char *ident, int logstat, int logfac)
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{
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THREAD_LOCK();
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pthread_cleanup_push(syslog_cancel_cleanup, NULL);
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openlog_unlocked(ident, logstat, logfac);
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pthread_cleanup_pop(1);
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}
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void
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closelog(void)
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{
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THREAD_LOCK();
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if (LogFile != -1) {
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(void)_close(LogFile);
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LogFile = -1;
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}
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LogTag = NULL;
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LogTagLength = -1;
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connected = false;
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THREAD_UNLOCK();
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}
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/* setlogmask -- set the log mask level */
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int
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setlogmask(int pmask)
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{
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int omask;
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THREAD_LOCK();
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omask = LogMask;
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if (pmask != 0)
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LogMask = pmask;
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THREAD_UNLOCK();
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return (omask);
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}
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/*
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* Obtain LogPid from LogTag formatted as per RFC 3164,
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* Section 5.3 Originating Process Information:
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*
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* ident[NNN]
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*/
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static void
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parse_tag(void)
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{
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char *begin, *end, *p;
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pid_t pid;
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if (LogTag == NULL || (LogStat & LOG_PID) != 0)
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return;
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/*
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* LogTagLength is -1 if LogTag was not parsed yet.
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* Avoid multiple passes over same LogTag.
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*/
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LogTagLength = 0;
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/* Check for presence of opening [ and non-empty ident. */
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if ((begin = strchr(LogTag, '[')) == NULL || begin == LogTag)
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return;
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/* Check for presence of closing ] at the very end and non-empty pid. */
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if ((end = strchr(begin + 1, ']')) == NULL || end[1] != 0 ||
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(end - begin) < 2)
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return;
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/* Check for pid to contain digits only. */
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pid = (pid_t)strtol(begin + 1, &p, 10);
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if (p != end)
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return;
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LogPid = pid;
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LogTagLength = begin - LogTag;
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}
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