ns_main.c

早期freebsd实现

#if !defined(lint) && !defined(SABER)
static char sccsid[] = "@(#)ns_main.c	4.55 (Berkeley) 7/1/91";
static char rcsid[] = "$Id: ns_main.c,v 4.9.1.8 1993/12/06 00:43:02 vixie Exp $";
#endif /* not lint */

/*
 * ++Copyright++ 1986, 1989, 1990
 * -
 * Copyright (c) 1986, 1989, 1990
 *    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.
 * -
 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
 * 
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies, and that
 * the name of Digital Equipment Corporation not be used in advertising or
 * publicity pertaining to distribution of the document or software without
 * specific, written prior permission.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 * -
 * --Copyright--
 */

#if !defined(lint) && !defined(SABER)
char copyright[] =
"@(#) Copyright (c) 1986, 1989, 1990 The Regents of the University of California.\n\
 portions Copyright (c) 1993 Digital Equipment Corporation\n\
 portions Copyright (c) 1993 Berkeley Network Software Consortium\n\
 All rights reserved.\n";
#endif /* not lint */

/*
 * Internet Name server (see rfc883 & others).
 */

#include <sys/param.h>
#include <sys/file.h>
#include <sys/stat.h>
#if !defined(SYSV) && defined(XXX)
#include <sys/wait.h>
#endif /* !SYSV */
#include <sys/time.h>
#define TIME_H_INCLUDED
#include <sys/resource.h>
#include <sys/ioctl.h>
#if defined(__osf__)
#define _SOCKADDR_LEN		/* XXX - should be in portability.h but that
				 * would need to be included before socket.h
				 */
#endif
#include <sys/socket.h>
#include <netinet/in.h>
#include <net/if.h>
#include <arpa/nameser.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <stdio.h>
#include <syslog.h>
#include <errno.h>
#include <signal.h>
#include <netdb.h>
#include <resolv.h>
#if defined(sun) && defined (SYSV)		/* Solaris 2 */
#include <sys/sockio.h>
#endif

#define MAIN_PROGRAM
#include "named.h"
#undef MAIN_PROGRAM

#undef nsaddr

#ifdef SO_RCVBUF
static int	rbufsize = 8 * 1024;		/* UDP recive buffer size */
#endif

static	struct sockaddr_in	nsaddr;
static	u_int16_t		local_ns_port;		/* our service port */
static	fd_set			mask;			/* open descriptors */
static	char			**Argv = NULL;
static	char			*LastArg = NULL;	/* end of argv */

static	struct qstream		*sqadd __P((void));
static	void			sq_query __P((struct qstream *)),
				opensocket __P((struct qdatagram *)),
#ifdef DEBUG
				printnetinfo __P((struct netinfo *)),
#endif
				setdebug __P((int));
static	int			sq_here __P((struct qstream *));

static	SIG_FN			onintr __P(()),
				maint_alarm __P(()),
				setdumpflg __P(()),
				onhup __P(()),
#if defined(QRYLOG) && defined(SIGWINCH)
				setQrylogFlg __P(()),
#endif
				setIncrDbgFlg __P(()),
				setNoDbgFlg __P(()),
				sigprof __P(()),
				setchkptflg __P(()),
				setstatsflg __P(());

static void
usage()
{
	fprintf(stderr,
"Usage: named [-d #] [-q] [-r] [-p port[/localport]] [[-b] bootfile]\n");
	exit(1);
}

/*ARGSUSED*/
void
main(argc, argv, envp)
	int argc;
	char *argv[], *envp[];
{
	register int n, udpcnt;
	register char *arg;
	register struct qstream *sp;
	register struct qdatagram *dqp;
	struct qstream *nextsp;
	int nfds;
	int on = 1;
	int rfd, size;
	time_t lasttime, maxctime;
	u_char buf[BUFSIZ];
#ifndef SYSV
	struct sigvec vec;
#endif
	fd_set tmpmask;
	struct timeval t, *tp;
	struct qstream *candidate = QSTREAM_NULL;
	char **argp;
#ifdef PID_FIX
	char oldpid[10];
#endif
#ifdef WANT_PIDFILE
	FILE	*fp;			/* file descriptor for pid file */
#endif

	local_ns_port = ns_port = htons(NAMESERVER_PORT);

	/*
	**  Save start and extent of argv for setproctitle.
	*/

	Argv = argp = argv;
	while (*argp)
		argp++;
	LastArg = argp[-1] + strlen(argp[-1]);

	(void) umask(022);
	/* XXX - should use getopt here */
	while (--argc > 0) {
		arg = *++argv;
		if (*arg == '-') {
			while (*++arg)
				switch (*arg) {
				case 'b':
					if (--argc <= 0)
						usage();
					bootfile = savestr(*++argv);
					break;

  				case 'd':
 					++argv;

 					if (*argv != 0) {
 					    if (**argv == '-') {
 						argv--;
 						break;
 					    }
 					    debug = atoi(*argv);
 					    --argc;
 					}
					if (debug <= 0)
						debug = 1;
					setdebug(1);
					break;

				case 'p':
					/* use nonstandard port number.
					 * usage: -p remote/local
					 * remote is the port number to which
					 * we send queries.  local is the port
					 * on which we listen for queries.
					 * local defaults to same as remote.
					 */
					if (--argc <= 0)
						usage();
					ns_port = htons((u_int16_t)
							atoi(*++argv));
					{
					    char *p = strchr(*argv, '/');
					    if (p) {
						local_ns_port =
						    htons((u_int16_t)
							  atoi(p+1));
					    } else {
						local_ns_port = ns_port;
					    }
					}
					break;

#ifdef QRYLOG
				case 'q':
					qrylog = 1;
					break;
#endif

				case 'r':
					NoRecurse = 1;
					break;

				default:
					usage();
				}
		} else
			bootfile = savestr(*argv);
	}

	if (!debug)
		for (n = getdtablesize() - 1; n > 2; n--)
			(void) close(n);	/* don't use my_close() here */
#ifdef DEBUG
	else {
		fprintf(ddt,"Debug turned ON, Level %d\n",debug);
		fprintf(ddt,"Version = %s\t",Version);
		fprintf(ddt,"bootfile = %s\n",bootfile);
	}		
#endif

#ifdef LOG_DAEMON
	openlog("named", LOG_PID|LOG_CONS|LOG_NDELAY, LOGFAC);
#else
	openlog("named", LOG_PID);
#endif

#ifdef WANT_PIDFILE
	/* tuck my process id away */
#ifdef PID_FIX
	fp = fopen(PidFile, "r+");
	if (fp != NULL) {
		(void) fgets(oldpid, sizeof(oldpid), fp);
		(void) rewind(fp);
		fprintf(fp, "%d\n", getpid());
		(void) my_fclose(fp);
	}
#else /*PID_FIX*/
	fp = fopen(PidFile, "w");
	if (fp != NULL) {
		fprintf(fp, "%d\n", getpid());
		(void) my_fclose(fp);
	}
#endif /*PID_FIX*/
#endif /*WANT_PIDFILE*/

	syslog(LOG_NOTICE, "starting.  %s", Version);

	_res.options &= ~(RES_DEFNAMES | RES_DNSRCH | RES_RECURSE);

	nsaddr.sin_family = AF_INET;
	nsaddr.sin_addr.s_addr = INADDR_ANY;
	nsaddr.sin_port = local_ns_port;

	/*
	** Open stream port.
	*/
	for (n = 0; ; n++) {
		if ((vs = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
			syslog(LOG_ERR, "socket(SOCK_STREAM): %m");
			exit(1);
		}	
		if (setsockopt(vs, SOL_SOCKET, SO_REUSEADDR, (char *)&on,
			sizeof(on)) != 0)
		{
			syslog(LOG_ERR, "setsockopt(vs, reuseaddr): %m");
			(void) my_close(vs);
			continue;
		}
		if (bind(vs, (struct sockaddr *)&nsaddr, sizeof(nsaddr)) == 0)
			break;

		if (errno != EADDRINUSE || n > 4) {
			if (errno == EADDRINUSE) {
				syslog(LOG_ERR,
				 "There may be a name server already running");
				syslog(LOG_ERR, "exiting");
			} else {
				syslog(LOG_ERR, "bind(vs, [%s].%d): %m",
					inet_ntoa(nsaddr.sin_addr),
					ntohs(nsaddr.sin_port));
			}
#if defined(WANT_PIDFILE) && defined(PID_FIX)
			/* put old pid back */
			if (atoi(oldpid) && (fp = fopen(PidFile, "w"))) {
				fprintf(fp, "%s", oldpid);
				(void) my_fclose(fp);
				_exit(1);
			}
#endif /*WANT_PIDFILE && PID_FIX*/
			exit(1);
		} else {	/* Retry opening the socket a few times */
			my_close(vs);
			sleep(1);
		}
	}
	if (listen(vs, 5) != 0) {
		syslog(LOG_ERR, "listen(vs, 5): %m");
		exit(1);
	}

	/*
	 * Get list of local addresses and set up datagram sockets.
	 */
	getnetconf();

	/*
	** Initialize and load database.
	*/
	gettime(&tt);
	buildservicelist();
	buildprotolist();
	ns_init(bootfile);
#ifdef DEBUG
	if (debug) {
		fprintf(ddt, "Network and sort list:\n");
		printnetinfo(nettab);
	}
#endif

	time(&boottime);
	resettime = boottime;

	(void) signal(SIGHUP, onhup);
#if defined(SIGXFSZ)
	(void) signal(SIGXFSZ, onhup);	/* wierd DEC Hesiodism, harmless */
#endif
#if defined(SYSV)
	(void) signal(SIGCLD, endxfer);
	(void) signal(SIGALRM, maint_alarm);
#else
	bzero((char *)&vec, sizeof(vec));
	vec.sv_handler = maint_alarm;
	vec.sv_mask = sigmask(SIGCHLD);
	(void) sigvec(SIGALRM, &vec, (struct sigvec *)NULL);

	vec.sv_handler = endxfer;
	vec.sv_mask = sigmask(SIGALRM);
	(void) sigvec(SIGCHLD, &vec, (struct sigvec *)NULL);
#endif /* SYSV */
	(void) signal(SIGPIPE, SIG_IGN);
	(void) signal(SIGSYS, sigprof);
	(void) signal(SIGINT, setdumpflg);
	(void) signal(SIGQUIT, setchkptflg);
	(void) signal(SIGIOT, setstatsflg);

#ifdef ALLOW_UPDATES
        /* Catch SIGTERM so we can dump the database upon shutdown if it
           has changed since it was last dumped/booted */
        (void) signal(SIGTERM, onintr);
#endif

#if defined(SIGUSR1) && defined(SIGUSR2)
	(void) signal(SIGUSR1, setIncrDbgFlg);
	(void) signal(SIGUSR2, setNoDbgFlg);
#else /* SIGUSR1&&SIGUSR2 */
	(void) signal(SIGEMT, setIncrDbgFlg);
	(void) signal(SIGFPE, setNoDbgFlg);
#endif /* SIGUSR1&&SIGUSR2 */

#if defined(SIGWINCH) && defined(QRYLOG)
	(void) signal(SIGWINCH, setQrylogFlg);
#endif

#ifdef DEBUG
	if (debug) {
		fprintf(ddt,"database initialized\n");
	}
#endif

	t.tv_usec = 0;

	/*
	 * Fork and go into background now that
	 * we've done any slow initialization
	 * and are ready to answer queries.
	 */
#ifdef USE_SETSID
	if (!debug || !isatty(0)) {
		if (fork() > 0)
			exit(0);
		setsid();
		if (!debug) {
			n = open(_PATH_DEVNULL, O_RDONLY);
			(void) dup2(n, 0);
			(void) dup2(n, 1);
			(void) dup2(n, 2);
			if (n > 2)
				(void) my_close(n);
		}
	}
#else
	if (!debug) {
#ifdef HAVE_DAEMON
		daemon(1, 0);
#else
		switch (fork()) {
		case -1:
			syslog(LOG_ERR, "fork: %m");
			exit(1);
			/*FALLTHROUGH*/
		case 0:
			/* child */
			break;
		default:
			/* parent */
			exit(0);
		}
		n = open(_PATH_DEVNULL, O_RDONLY);
		(void) dup2(n, 0);
		(void) dup2(n, 1);
		(void) dup2(n, 2);
		if (n > 2)
			(void) my_close(n);
#ifdef SYSV
		setpgrp();
#else
		{
			struct itimerval ival;

			/*
			 * The open below may hang on pseudo ttys if the person
			 * who starts named logs out before this point.
			 *
			 * needmaint may get set inapropriately if the open
			 * hangs, but all that will happen is we will see that
			 * no maintenance is required.
			 */
			bzero((char *)&ival, sizeof(ival));
			ival.it_value.tv_sec = 120;
			(void) setitimer(ITIMER_REAL, &ival,
				    (struct itimerval *)NULL);
			n = open(_PATH_TTY, O_RDWR);
			ival.it_value.tv_sec = 0;
			(void) setitimer(ITIMER_REAL, &ival,
				    (struct itimerval *)NULL);
			if (n > 0) {
				(void) ioctl(n, TIOCNOTTY, (char *)NULL);
				(void) my_close(n);
			}
		}
#endif /* SYSV */
#endif /* HAVE_DAEMON */
	}
#endif /* USE_SETSID */
#ifdef WANT_PIDFILE
	/* tuck my process id away again */
	fp = fopen(PidFile, "w");
	if (fp != NULL) {
		fprintf(fp, "%d\n", getpid());
		(void) my_fclose(fp);
	}
#endif

#ifdef DEBUG
	if (debug)
		fprintf(ddt,"Ready to answer queries.\n");
#endif