main.c

早期freebsd实现

/*
 * ++Copyright++ 1985, 1989
 * -
 * Copyright (c) 1985, 1989
 *    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--
 */

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1985,1989 Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)main.c	5.42 (Berkeley) 3/3/91";
static char rcsid[] = "$Id: main.c,v 4.9.1.3 1993/09/16 09:02:07 vixie Exp $";
#endif /* not lint */

/*
 ******************************************************************************
 *  
 *   main.c --
 *  
 *	Main routine and some action routines for the name server
 *	lookup program.
 *
 *	Andrew Cherenson
 *	U.C. Berkeley Computer Science Div.
 *	CS298-26, Fall 1985
 *  
 ******************************************************************************
 */

#include <sys/param.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <arpa/inet.h>
#include <resolv.h>
#include <signal.h>
#include <setjmp.h>
#include <ctype.h>
#include <stdio.h>
#include <errno.h>
#include <limits.h>
#include "res.h"
#include "pathnames.h"
#include "../../conf/portability.h"


/*
 * Name of a top-level name server. Can be changed with 
 * the "set root" command.
 */

#ifndef ROOT_SERVER
#define		ROOT_SERVER "ns.internic.net."
#endif
char		rootServerName[NAME_LEN] = ROOT_SERVER;


/*
 *  Import the state information from the resolver library.
 */

extern struct __res_state _res;


/*
 *  Info about the most recently queried host.
 */

HostInfo	curHostInfo;
int		curHostValid = FALSE;


/*
 *  Info about the default name server.
 */

HostInfo	*defaultPtr = NULL;
char		defaultServer[NAME_LEN];
struct in_addr	defaultAddr;


/*
 *  Initial name server query type is Address.
 */

int		queryType = T_A;
int		queryClass = C_IN;

/*
 * Stuff for Interrupt (control-C) signal handler.
 */

extern SIG_FN	IntrHandler();
FILE		*filePtr;
jmp_buf		env;


/*
 * Browser command for help and view.
 */
char		*pager;

static void CvtAddrToPtr();
static void ReadRC();


/*
 ******************************************************************************
 *
 *  main --
 *
 *	Initializes the resolver library and determines the address
 *	of the initial name server. The yylex routine is used to
 *	read and perform commands.
 *
 ******************************************************************************
 */

main(argc, argv)
    int		argc;
    char	**argv;
{
    char	*wantedHost = NULL;
    Boolean	useLocalServer;
    int		result;
    int		i;
    struct hostent	*hp;

    /*
     *  Initialize the resolver library routines.
     */

    if (res_init() == -1) {
	fprintf(stderr,"*** Can't initialize resolver.\n");
	exit(1);
    }

    /*
     *  Allocate space for the default server's host info and
     *  find the server's address and name. If the resolver library
     *  already has some addresses for a potential name server,
     *  then use them. Otherwise, see if the current host has a server.
     *  Command line arguments may override the choice of initial server. 
     */

    defaultPtr = (HostInfo *) Calloc(1, sizeof(HostInfo));

    /*
     * Parse the arguments:
     *  no args =  go into interactive mode, use default host as server
     *	1 arg	=  use as host name to be looked up, default host will be server
     *		   non-interactive mode
     *  2 args	=  1st arg: 
     *		     if it is '-', then 
     *		        ignore but go into interactive mode
     *		     else 
     *		         use as host name to be looked up, 
     *			 go into non-interactive mode
     *		2nd arg: name or inet address of server
     *
     *	"Set" options are specified with a leading - and must come before
     *	any arguments. For example, to find the well-known services for
     *  a host, type "nslookup -query=wks host"
     */

    ReadRC();			/* look for options file */

    ++argv; --argc;		/* skip prog name */

    while (argc && *argv[0] == '-' && argv[0][1]) {
	(void) SetOption (&(argv[0][1]));
	++argv; --argc;
    }
    if (argc > 2) {
	Usage();
    } 
    if (argc && *argv[0] != '-') {
	wantedHost = *argv;	/* name of host to be looked up */
    }

    useLocalServer = FALSE;
    if (argc == 2) {
	struct in_addr addr;

	/*
	 * Use an explicit name server. If the hostname lookup fails,
	 * default to the server(s) in resolv.conf.
	 */ 

	if (inet_aton(*++argv, &addr)) {
	    _res.nscount = 1;
	    _res.nsaddr.sin_addr = addr;
	} else {
	    hp = gethostbyname(*argv);
	    if (hp == NULL) {
		fprintf(stderr, "*** Can't find server address for '%s': ", 
			*argv);
		herror((char *)NULL);
		fputc('\n', stderr);
	    } else {
		for (i = 0; i < MAXNS && hp->h_addr_list[i] != NULL; i++) {
		    bcopy(hp->h_addr_list[i], 
			    (char *)&_res.nsaddr_list[i].sin_addr, 
			    hp->h_length);
		}
		_res.nscount = i;
	    } 
	}
    }


    if (_res.nscount == 0 || useLocalServer) {
	LocalServer(defaultPtr);
    } else {
	for (i = 0; i < _res.nscount; i++) {
	    if (_res.nsaddr_list[i].sin_addr.s_addr == INADDR_ANY) {
	        LocalServer(defaultPtr);
		break;
	    } else {
		result = GetHostInfoByAddr(&(_res.nsaddr_list[i].sin_addr), 
				    &(_res.nsaddr_list[i].sin_addr), 
				    defaultPtr);
		if (result != SUCCESS) {
		    fprintf(stderr,
		    "*** Can't find server name for address %s: %s\n", 
		       inet_ntoa(_res.nsaddr_list[i].sin_addr), 
		       DecodeError(result));
		} else {
		    defaultAddr = _res.nsaddr_list[i].sin_addr;
		    break;
		}
	    }
	}

	/*
	 *  If we have exhausted the list, tell the user about the
	 *  command line argument to specify an address.
	 */

	if (i == _res.nscount) {
	    fprintf(stderr, "*** Default servers are not available\n");
	    exit(1);
	}

    }
    strcpy(defaultServer, defaultPtr->name);


#ifdef DEBUG
#ifdef DEBUG2
    _res.options |= RES_DEBUG2;
#endif
    _res.options |= RES_DEBUG;
    _res.retry    = 2;
#endif /* DEBUG */

    /*
     * If we're in non-interactive mode, look up the wanted host and quit.
     * Otherwise, print the initial server's name and continue with
     * the initialization.
     */

    if (wantedHost != (char *) NULL) {
	LookupHost(wantedHost, 0);
    } else {
	PrintHostInfo(stdout, "Default Server:", defaultPtr);

	pager = getenv("PAGER");
	if (pager == NULL) {
	    pager = _PATH_PAGERCMD;
	}

	/*
	 * Setup the environment to allow the interrupt handler to return here.
	 */

	(void) setjmp(env);

	/* 
	 * Return here after a longjmp.
	 */

	signal(SIGINT, IntrHandler);
	signal(SIGPIPE, SIG_IGN);

	/*
	 * Read and evaluate commands. The commands are described in commands.l
	 * Yylex returns 0 when ^D or 'exit' is typed. 
	 */

	printf("> ");
	fflush(stdout);
	while(yylex()) {
	    printf("> ");
	    fflush(stdout);
	}
    }
    exit(0);
}


LocalServer(defaultPtr)
    HostInfo *defaultPtr;
{
    char	hostName[NAME_LEN];

    (void) gethostname(hostName, sizeof(hostName));

    defaultAddr.s_addr = htonl(INADDR_ANY);
    (void) GetHostInfoByName(&defaultAddr, C_IN, T_A,
			     "0.0.0.0", defaultPtr, 1);
    free(defaultPtr->name);
    defaultPtr->name = Calloc(1, sizeof(hostName)+1);
    strcpy(defaultPtr->name, hostName);
}


/*
 ******************************************************************************
 *
 *  Usage --
 *
 *	Lists the proper methods to run the program and exits.
 *
 ******************************************************************************
 */

Usage()
{
    fprintf(stderr, "Usage:\n");
    fprintf(stderr,
"   nslookup [-opt ...]             # interactive mode using default server\n");
    fprintf(stderr,
"   nslookup [-opt ...] - server    # interactive mode using 'server'\n");
    fprintf(stderr,
"   nslookup [-opt ...] host        # just look up 'host' using default server\n");
    fprintf(stderr,
"   nslookup [-opt ...] host server # just look up 'host' using 'server'\n");
    exit(1);
}

/*
 ******************************************************************************
 *
 * IsAddr --
 *
 *	Returns TRUE if the string looks like an Internet address.
 *	A string with a trailing dot is not an address, even if it looks
 *	like one.
 *
 ******************************************************************************
 */

Boolean
IsAddr(host, addrPtr)
    char *host;
    struct in_addr *addrPtr;	/* If return TRUE, contains IP address */
{
    register char *cp;

    if (isdigit(host[0])) {
	    /* Make sure it has only digits and dots. */
	    for (cp = host; *cp; ++cp) {
		if (!isdigit(*cp) && *cp != '.') 
		    return FALSE;
	    }
	    /* If it has a trailing dot, don't treat it as an address. */
	    if (*--cp != '.') { 
		return inet_aton(host, addrPtr);
	    }
    }
    return FALSE;
}


/*
 ******************************************************************************
 *
 *  SetDefaultServer --
 *
 *	Changes the default name server to the one specified by
 *	the first argument. The command "server name" uses the current 
 *	default server to lookup the info for "name". The command
 *	"lserver name" uses the original server to lookup "name".
 *
 *  Side effects:
 *	This routine will cause a core dump if the allocation requests fail.
 *
 *  Results:
 *	SUCCESS		The default server was changed successfully.
 *	NONAUTH		The server was changed but addresses of
 *			other servers who know about the requested server
 *			were returned.
 *	Errors		No info about the new server was found or
 *			requests to the current server timed-out.
 *
 ******************************************************************************
 */

int
SetDefaultServer(string, local)
    char	*string;
    Boolean	local;
{
    register HostInfo	*newDefPtr;
    struct in_addr	*servAddrPtr;
    struct in_addr	addr;
    char		newServer[NAME_LEN];
    int			result;
    int			i;

    /*
     *  Parse the command line. It maybe of the form "server name",
     *  "lserver name" or just "name".
     */

    if (local) {
	i = sscanf(string, " lserver %s", newServer);
    } else {
	i = sscanf(string, " server %s", newServer);
    }
    if (i != 1) {
	i = sscanf(string, " %s", newServer);
	if (i != 1) {
	    fprintf(stderr,"SetDefaultServer: invalid name: %s\n",  string);
	    return(ERROR);
	}
    }

    /*
     * Allocate space for a HostInfo variable for the new server. Don't
     * overwrite the old HostInfo struct because info about the new server
     * might not be found and we need to have valid default server info.
     */

    newDefPtr = (HostInfo *) Calloc(1, sizeof(HostInfo));


    /*
     *	A 'local' lookup uses the original server that the program was
     *  initialized with.
     *
     *  Check to see if we have the address of the server or the
     *  address of a server who knows about this domain.
     *  XXX For now, just use the first address in the list.
     */

    if (local) {
	servAddrPtr = &defaultAddr;
    } else if (defaultPtr->addrList != NULL) {
	servAddrPtr = (struct in_addr *) defaultPtr->addrList[0];
    } else {
	servAddrPtr = (struct in_addr *) defaultPtr->servers[0]->addrList[0];
    }

    result = ERROR;
    if (IsAddr(newServer, &addr)) {
	result = GetHostInfoByAddr(servAddrPtr, &addr, newDefPtr);
	/* If we can't get the name, fall through... */
    } 
    if (result != SUCCESS && result != NONAUTH) {
	result = GetHostInfoByName(servAddrPtr, C_IN, T_A, 
			newServer, newDefPtr, 1);
    }

    if (result == SUCCESS || result == NONAUTH) {
	    /*
	     *  Found info about the new server. Free the resources for
	     *  the old server.
	     */

	    FreeHostInfoPtr(defaultPtr);
	    free((char *)defaultPtr);
	    defaultPtr = newDefPtr;
	    strcpy(defaultServer, defaultPtr->name);
	    PrintHostInfo(stdout, "Default Server:", defaultPtr);
	    return(SUCCESS);
    } else {
	    fprintf(stderr, "*** Can't find address for server %s: %s\n",
		    newServer, DecodeError(result));
	    free((char *)newDefPtr);

	    return(result);
    }
}

/*
 ******************************************************************************
 *
 * DoLoookup --
 *
 *	Common subroutine for LookupHost and LookupHostWithServer.
 *
 *  Results:
 *	SUCCESS		- the lookup was successful.
 *	Misc. Errors	- an error message is printed if the lookup failed.
 *
 ******************************************************************************
 */

static int
DoLookup(host, servPtr, serverName)
    char	*host;
    HostInfo	*servPtr;