05eb11cbc4
This fixes a race condition where another thread may fork() before CLOEXEC is set, unintentionally passing the descriptor to the child process. This commit only adds O_CLOEXEC flags to open() or openat() calls where no fcntl(fd, F_SETFD, FD_CLOEXEC) follows. The separate fcntl() call still leaves a race window so it should be fixed later.
439 lines
11 KiB
C
439 lines
11 KiB
C
/*
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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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* 4. 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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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)syslog.c 8.5 (Berkeley) 4/29/95";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "namespace.h"
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/syslog.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 <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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static int LogFile = -1; /* fd for log */
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static int status; /* connection status */
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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 const char *LogTag = NULL; /* string to tag the entry with */
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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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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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enum {
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NOCONN = 0,
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CONNDEF,
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CONNPRIV,
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};
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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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void
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vsyslog(int pri, const char *fmt, va_list ap)
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{
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int cnt;
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char ch, *p;
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time_t now;
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int fd, saved_errno;
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char *stdp, tbuf[2048], fmt_cpy[1024], timbuf[26], errstr[64];
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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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THREAD_LOCK();
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/* Check priority against setlogmask values. */
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if (!(LOG_MASK(LOG_PRI(pri)) & LogMask)) {
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THREAD_UNLOCK();
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return;
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}
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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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THREAD_UNLOCK();
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return;
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}
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/* Build the message. */
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(void)time(&now);
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(void)fprintf(fp, "<%d>", pri);
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(void)fprintf(fp, "%.15s ", ctime_r(&now, timbuf) + 4);
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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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if (LogTag == NULL)
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LogTag = _getprogname();
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if (LogTag != NULL)
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(void)fprintf(fp, "%s", LogTag);
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if (LogStat & LOG_PID)
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(void)fprintf(fp, "[%d]", getpid());
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if (LogTag != NULL) {
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(void)fprintf(fp, ": ");
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}
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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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THREAD_UNLOCK();
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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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(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
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* 2) /var/run/log is out of socket buffer space, which
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* in most cases means local DoS.
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* We attempt to reconnect to /var/run/log[priv] to take care of
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* case #1 and keep send()ing data to cover case #2
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* to give syslogd a chance to empty its socket buffer.
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*
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* If we are working with a priveleged socket, then take
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* only one attempt, because we don't want to freeze a
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* critical application like su(1) or sshd(8).
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*
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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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}
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do {
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if (status == CONNPRIV)
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break;
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_usleep(1);
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if (send(LogFile, tbuf, cnt, 0) >= 0) {
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THREAD_UNLOCK();
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return;
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}
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} while (errno == ENOBUFS);
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} else {
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THREAD_UNLOCK();
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return;
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}
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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, '>') + 1;
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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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THREAD_UNLOCK();
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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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status = NOCONN; /* 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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if ((LogFile = _socket(AF_UNIX, SOCK_DGRAM, 0)) == -1)
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return;
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(void)_fcntl(LogFile, F_SETFD, FD_CLOEXEC);
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}
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if (LogFile != -1 && status == NOCONN) {
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SyslogAddr.sun_len = sizeof(SyslogAddr);
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SyslogAddr.sun_family = AF_UNIX;
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/*
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* First try priveleged socket. If no success,
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* then try default socket.
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*/
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(void)strncpy(SyslogAddr.sun_path, _PATH_LOG_PRIV,
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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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status = CONNPRIV;
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if (status == NOCONN) {
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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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status = CONNDEF;
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}
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if (status == NOCONN) {
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/*
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* Try the old "/dev/log" path, for backward
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* compatibility.
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*/
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(void)strncpy(SyslogAddr.sun_path, _PATH_OLDLOG,
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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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status = CONNDEF;
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}
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if (status == NOCONN) {
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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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LogStat = logstat;
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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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openlog_unlocked(ident, logstat, logfac);
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THREAD_UNLOCK();
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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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status = NOCONN;
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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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