subr.c

一个可用的dns服务器源代码

/*
 * ++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
static char sccsid[] = "@(#)subr.c	5.24 (Berkeley) 3/2/91";
static char rcsid[] = "$Id: subr.c,v 8.6 1996/08/08 06:54:51 vixie Exp $";
#endif /* not lint */

/*
 *******************************************************************************
 *
 *  subr.c --
 *
 *	Miscellaneous subroutines for the name server
 *	lookup program.
 *
 *	Copyright (c) 1985
 *	Andrew Cherenson
 *	U.C. Berkeley
 *	CS298-26  Fall 1985
 *
 *******************************************************************************
 */


#ifndef WINNT
#include <sys/types.h>
#include <sys/param.h>
#endif
#include <netdb.h>
#ifndef WINNT
#include <sys/socket.h>
#include <netinet/in.h>
#endif
#include <nameser.h>
#include <inet.h>
#include <signal.h>
#ifndef WINNT
#include <setjmp.h>
#endif
#include <stdio.h>
#include "resolv.h"
#include "res.h"
#include "portability.h"

#ifdef WINNT
#ifdef GUI
	char output[10000];
	char final_output[10000];
#endif
#endif


/*
 *******************************************************************************
 *
 *  IntrHandler --
 *
 *	This routine is called whenever a control-C is typed.
 *	It performs three main functions:
 *	 - closes an open socket connection,
 *	 - closes an open output file (used by LookupHost, et al.),
 *	 - jumps back to the main read-eval loop.
 *
 *	If a user types a ^C in the middle of a routine that uses a socket,
 *	the routine would not be able to close the socket. To prevent an
 *	overflow of the process's open file table, the socket and output
 *	file descriptors are closed by the interrupt handler.
 *
 *  Side effects:
 *	Open file descriptors are closed.
 *	If filePtr is valid, it is closed.
 *	Flow of control returns to the main() routine.
 *
 *******************************************************************************
 */
 #ifndef WINNT

SIG_FN
IntrHandler()
{
    extern jmp_buf env;
#if defined(BSD) && BSD >= 199006 && !defined(RISCOS_BSD) && !defined(__osf__)
    extern FILE *yyin;		/* scanner input file */
    extern void yyrestart();	/* routine to restart scanner after interrupt */
#endif

    SendRequest_close();
    ListHost_close();
    if (filePtr != NULL && filePtr != stdout) {
	fclose(filePtr);
	filePtr = NULL;
    }
    printf("\n");
#if defined(BSD) && BSD >= 199006 && !defined(RISCOS_BSD) && !defined(__osf__)
    yyrestart(yyin);
#endif
    longjmp(env, 1);
}

 #endif
/*
 *******************************************************************************
 *
 *  Malloc --
 *  Calloc --
 *
 *      Calls the malloc library routine with SIGINT blocked to prevent
 *	corruption of malloc's data structures. We need to do this because
 *	a control-C doesn't kill the program -- it causes a return to the
 *	main command loop.
 *
 *	NOTE: This method doesn't prevent the pointer returned by malloc
 *	from getting lost, so it is possible to get "core leaks".
 *
 *	If malloc fails, the program exits.
 *
 *  Results:
 *	(address)	- address of new buffer.
 *
 *******************************************************************************
 */

char *
Malloc(size)
    int size;
{
    char	*ptr;

#ifdef SYSV
#if defined(SVR3) || defined(SVR4)
    sighold(SIGINT);
    ptr = malloc((unsigned) size);
    sigrelse(SIGINT);
#else
    { SIG_FN (*old)();
      old = signal(SIGINT, SIG_IGN);
      ptr = malloc((unsigned) size);
      signal(SIGINT, old);
    }
#endif
#else
#ifdef POSIX_SIGNALS
    { sigset_t sset;
      sigemptyset(&sset);
      sigaddset(&sset,SIGINT);
      sigprocmask(SIG_BLOCK,&sset,NULL);
      ptr = malloc((unsigned) size);
      sigprocmask(SIG_UNBLOCK,&sset,NULL);
    }
#else
    { 
      #ifndef WINNT
	  int saveMask;
      saveMask = sigblock(sigmask(SIGINT));
      #endif
      ptr = malloc((unsigned) size);
     #ifndef WINNT
      (void) sigsetmask(saveMask);
     #endif
    }
#endif
#endif
    if (ptr == NULL) {
	fflush(stdout);
	fprintf(stderr, "*** Can't allocate memory\n");
	fflush(stderr);
	abort();
	/*NOTREACHED*/
    } else {
	return(ptr);
    }
}

char *
Calloc(num, size)
    register int num, size;
{
    char *ptr = Malloc(num*size);
    bzero(ptr, num*size);
    return(ptr);
}


/*
 *******************************************************************************
 *
 *  PrintHostInfo --
 *
 *	Prints out the HostInfo structure for a host.
 *
 *******************************************************************************
 */


void
PrintHostInfo(file, title, hp)
	FILE	*file;
	char	*title;
	register HostInfo *hp;
{
	register char		**cp;
	register ServerInfo	**sp;
	char			comma;
	int			i;

     if (file == NULL)
       file = stdout;

	fprintf(file, "%-7s  %s", title, hp->name);

	if (hp->addrList != NULL) {
	    if (hp->addrList[1] != NULL) {
		fprintf(file, "\nAddresses:");
	    } else {
		fprintf(file, "\nAddress:");
	    }
	    comma = ' ';
	    i = 0;
	    for (cp = hp->addrList; cp && *cp; cp++) {
		i++;
		if (i > 4) {
		    fprintf(file, "\n\t");
		    comma = ' ';
		    i = 0;
		}
		fprintf(file,"%c %s", comma, inet_ntoa(*(struct in_addr *)*cp));
		comma = ',';
	    }
	}

	if (hp->aliases != NULL) {
	    fprintf(file, "\nAliases:");
	    comma = ' ';
	    i = 10;
	    for (cp = hp->aliases; cp && *cp && **cp; cp++) {
		i += strlen(*cp) + 2;
		if (i > 75) {
		    fprintf(file, "\n\t");
		    comma = ' ';
		    i = 10;
		}
		fprintf(file, "%c %s", comma, *cp);
		comma = ',';
	    }
	}

	if (hp->servers != NULL) {
	    fprintf(file, "\nServed by:\n");
	    for (sp = hp->servers; *sp != NULL ; sp++) {

		fprintf(file, "- %s\n\t",  (*sp)->name);

		comma = ' ';
		i = 0;
		for (cp = (*sp)->addrList; cp && *cp && **cp; cp++) {
		    i++;
		    if (i > 4) {
			fprintf(file, "\n\t");
			comma = ' ';
			i = 0;
		    }
		    fprintf(file,
			"%c %s", comma, inet_ntoa(*(struct in_addr *)*cp));
		    comma = ',';
		}
		fprintf(file, "\n\t");

		comma = ' ';
		i = 10;
		for (cp = (*sp)->domains; cp && *cp && **cp; cp++) {
		    i += strlen(*cp) + 2;
		    if (i > 75) {
			fprintf(file, "\n\t");
			comma = ' ';
			i = 10;
		    }
		    fprintf(file, "%c %s", comma, *cp);
		    comma = ',';
		}
		fprintf(file, "\n");
	    }
	}

	fprintf(file, "\n\n");
}


 
/*void
PrintHostInfo(file, title, hp)
	FILE	*file;
	char	*title;
	register HostInfo *hp;
{
	register char		**cp;
	register ServerInfo	**sp;
	char			comma;
	int			i;
	void PrintToBox(char *output);
	
	sprintf(final_output, "%-7s  %s", title, hp->name);

	if (hp->addrList != NULL) {
	    if (hp->addrList[1] != NULL) {
		sprintf(output, "\nAddresses:");
          strcat(final_output,output);

	    } else {
		sprintf(output, "\nAddress:");
          strcat(final_output,output);

	    }
	    comma = ' ';
	    i = 0;
	    for (cp = hp->addrList; cp && *cp; cp++) {
		i++;
		if (i > 4) {
		    sprintf(output, "\n\t");
              strcat(final_output,output);

		    comma = ' ';
		    i = 0;
		}
		sprintf(output,"%c %s", comma, inet_ntoa(*(struct in_addr *)*cp));
          strcat(final_output,output);

          comma = ',';
	    }
	}

	if (hp->aliases != NULL) {
	    sprintf(output, "\nAliases:");
         strcat(final_output,output);

	    comma = ' ';
	    i = 10;
	    for (cp = hp->aliases; cp && *cp && **cp; cp++) {
		i += strlen(*cp) + 2;
		if (i > 75) {
		    sprintf(output, "\n\t");
              strcat(final_output,output);

		    comma = ' ';
		    i = 10;
		}
		sprintf(output, "%c %s", comma, *cp);
          strcat(final_output,output);

		comma = ',';
	    }
	}

	if (hp->servers != NULL) {
	    sprintf(output, "\nServed by:\n");
         strcat(final_output,output);

	    for (sp = hp->servers; *sp != NULL ; sp++) {

		sprintf(output, "- %s\n\t",  (*sp)->name);
          strcat(final_output,output);


		comma = ' ';
		i = 0;
		for (cp = (*sp)->addrList; cp && *cp && **cp; cp++) {
		    i++;
		    if (i > 4) {
			sprintf(output, "\n\t");
               strcat(final_output,output);

               comma = ' ';
			i = 0;
		    }
		    sprintf(output,
			"%c %s", comma, inet_ntoa(*(struct in_addr *)*cp));
              strcat(final_output,output);

              comma = ',';
		}
		sprintf(output, "\n\t");
          strcat(final_output,output);

		comma = ' ';
		i = 10;
		for (cp = (*sp)->domains; cp && *cp && **cp; cp++) {
		    i += strlen(*cp) + 2;
		    if (i > 75) {
			sprintf(output, "\n\t");
                    strcat(final_output,output);

               comma = ' ';
			i = 10;
		    }
		    sprintf(output, "%c %s", comma, *cp);
                   strcat(final_output,output);

              comma = ',';
		}
		sprintf(output, "\n");
              strcat(final_output,output);

         }
	}

	sprintf(output, "\n\n");
     strcat(final_output,output);
     PrintToBox(final_output,0);
}

*/
/*
 *******************************************************************************
 *
 *  AppOpenFile --
 *
 *	Parses a command string for a file name and opens
 *	the file.
 *
 *  Results:
 *	file pointer	- the open was successful.
 *	NULL		- there was an error opening the file or
 *			  the input string was invalid.
 *
 *******************************************************************************
 */

FILE *
AppOpenFile(string, file)
    char *string;
    char *file;
{
	char	*redirect;
	FILE	*tmpPtr;

	/*
	 *  Open an output file if we see '>' or >>'.
	 *  Check for overwrite (">") or concatenation (">>").
	 */

	redirect = strchr(string, '>');
	if (redirect == NULL) {
	    return(NULL);
	}
	if (redirect[1] == '>') {
	    sscanf(redirect, ">> %s", file);
	    tmpPtr = fopen(file, "a+");
	} else {
	    sscanf(redirect, "> %s", file);
	    tmpPtr = fopen(file, "w");
	}

	if (tmpPtr != NULL) {
	    redirect[0] = '\0';
	}

	return(tmpPtr);
}

/*
 *******************************************************************************
 *
 *  DecodeError --
 *
 *	Converts an error code into a character string.
 *
 *******************************************************************************
 */

const struct res_sym error_syms[] = {
	{ NOERROR,	"Success" },
	{ FORMERR,	"Format error" },
	{ SERVFAIL,	"Server failed" },
	{ NXDOMAIN,	"Non-existent host/domain" },
	{ NOTIMP,	"Not implemented" },
	{ REFUSED,	"Query refused" },
#ifdef NOCHANGE
	{ NOCHANGE,	"No change" },
#endif
	{ TIME_OUT,	"Timed out" },
	{ NO_INFO,	"No information" },
	{ ERROR,	"Unspecified error" },
	{ NONAUTH,	"Non-authoritative answer" },
	{ NO_RESPONSE,	"No response from server" },
	{ 0,		NULL }
};

const char *
DecodeError(result)
    int result;
{
	const char *string;
	int success;

	string = sym_ntos(error_syms, result, &success);
	if (success)
		return string;
	return ("BAD ERROR VALUE");
}


int
StringToClass(class, dflt, errorfile)
    char *class;
    int dflt;
    FILE *errorfile;
{
	int result, success;

	result = sym_ston(__p_class_syms, class, &success);
	if (success)
		return result;

	if (errorfile)
		fprintf(errorfile, "unknown query class: %s\n", class);
	return(dflt);
}


/*
 *******************************************************************************
 *
 *  StringToType --
 *
 *	Converts a string form of a query type name to its
 *	corresponding integer value.
 *
 *******************************************************************************
 */

int
StringToType(type, dflt, errorfile)
    char *type;
    int dflt;
    FILE *errorfile;
{
	int result, success;

	result = sym_ston(__p_type_syms, type, &success);
	if (success)
		return (result);

	if (errorfile)
		fprintf(errorfile, "unknown query type: %s\n", type);
	return (dflt);
}

/*
 *******************************************************************************
 *
 *  DecodeType --
 *
 *	Converts a query type to a descriptive name.
 *	(A more verbose form of p_type.)
 *
 *
 *******************************************************************************
 */

const char *
DecodeType(type)
	int type;
{

	return (sym_ntop(__p_type_syms, type, (int *)0));
}