host.c

操作系统源代码

/*
 * Copyright (c) 1986 Regents of the University of California
 * All Rights Reserved
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that this notice is preserved and that due credit is given
 * to the University of California at Berkeley. The name of the University
 * may not be used to endorse or promote products derived from this
 * software without specific prior written permission. This software
 * is provided ``as is'' without express or implied warranty.
 */

/*
 * Actually, this program is from Rutgers University, however it is 
 * based on nslookup and other pieces of named tools, so it needs
 * that copyright notice.
 */

#if _MINIX
#include <sys/types.h>
#include <sys/ioctl.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <net/hton.h>
#include <net/netlib.h>
#include <net/gen/in.h>
#include <net/gen/inet.h>
#include <net/gen/netdb.h>
#include <net/gen/nameser.h>
#include <net/gen/resolv.h>
#include <net/gen/socket.h>
#include <net/gen/tcp.h>
#include <net/gen/tcp_io.h>

typedef u8_t u_char;
typedef u16_t u_short;
typedef u32_t u_long;

#undef ERROR
#else
#include <stdio.h>
#include <sys/types.h>
#include <arpa/nameser.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <resolv.h>
#include <sys/param.h>
#include <strings.h>
#include <ctype.h>
#endif

extern int h_errno;

#define NUMMX 50

#define  SUCCESS		0
#define  TIME_OUT		-1
#define  NO_INFO 		-2
#define  ERROR 			-3
#define  NONAUTH 		-4

#define NAME_LEN 256

#ifndef T_TXT
#define T_TXT 16
#endif
#ifndef NO_DATA
#define NO_DATA NO_ADDRESS
#endif
#ifndef C_HS
#define C_HS 4
#endif

FILE *filePtr;

struct state orig;
extern struct state _res;
static u8_t *cname = NULL;
int getclass = C_IN;
int gettype;
int verbose = 0;
int list = 0;
int server_specified = 0;

union querybuf;

void main _ARGS(( int c, char *v[] ));

static int parsetype _ARGS(( char *s ));
static int parseclass _ARGS(( char *s ));
static void hperror _ARGS(( int errno ));
static void printanswer _ARGS(( struct hostent *hp ));
static int ListHosts _ARGS(( char *namePtr, int queryType ));
static int gethostinfo _ARGS(( char *name ));
static int getdomaininfo _ARGS(( char *name, char *domain ));
static int getinfo _ARGS(( char *name, char *domain, int type ));
static int printinfo _ARGS(( union querybuf *answer, u8_t *eom, int filter, 
								int isls ));
static char *DecodeError _ARGS(( int result ));
static u8_t *pr_rr _ARGS(( u8_t *cp, u8_t *msg, FILE *file, int filter ));
static u8_t * pr_cdname _ARGS(( u8_t *cp, u8_t *msg, u8_t *name, int namelen ));
static char *pr_class _ARGS(( int class ));
static char *pr_type _ARGS(( int type ));
static int tcpip_writeall _ARGS(( int fd, char *buf, unsigned siz ));

void
main(c, v)
	char **v;
{
	ipaddr_t addr;
	register struct hostent *hp;
	register char *s;
	register inverse = 0;
	register waitmode = 0;
	u8_t *oldcname;
	int ncnames;

	res_init();
	_res.retrans = 5;

	if (c < 2) {
		fprintf(stderr, "Usage: host [-w] [-v] [-r] [-d] [-t querytype] [-c class] [-a] host [server]\n  -w to wait forever until reply\n  -v for verbose output\n  -r to disable recursive processing\n  -d to turn on debugging output\n  -t querytype to look for a specific type of information\n  -c class to look for non-Internet data\n  -a is equivalent to '-v -t *'\n");
		exit(1);
	}
	while (c > 2 && v[1][0] == '-') {
		if (strcmp (v[1], "-w") == 0) {
			_res.retry = 1;
			_res.retrans = 15;
			waitmode = 1;
			v++;
			c--;
		}
		else if (strcmp (v[1], "-r") == 0) {
			_res.options &= ~RES_RECURSE;
			v++;
			c--;
		}
		else if (strcmp (v[1], "-d") == 0) {
			_res.options |= RES_DEBUG;
			v++;
			c--;
		}
		else if (strcmp (v[1], "-v") == 0) {
			verbose = 1;
			v++;
			c--;
		}
		else if (strcmp (v[1], "-l") == 0) {
			list = 1;
			v++;
			c--;
		}
		else if (strncmp (v[1], "-t", 2) == 0) {
			v++;
			c--;
			gettype = parsetype(v[1]);
			v++;
			c--;
		}
		else if (strncmp (v[1], "-c", 2) == 0) {
			v++;
			c--;
			getclass = parseclass(v[1]);
			v++;
			c--;
		}
		else if (strcmp (v[1], "-a") == 0) {
			verbose = 1;
			gettype = T_ANY;
			v++;
			c--;
		}		
        }
	if (c > 2) {
		s = v[2];
		server_specified++;
		
		addr = inet_addr(s);
		if (addr == -1) {
		  hp = gethostbyname(s);
		  if (hp == NULL) {
		    fprintf(stderr,"Error in looking up server name:\n");
		    hperror(h_errno);
		    exit(1);
		  }
		  _res.nsaddr= *(ipaddr_t *)hp->h_addr;
		  printf("Using domain server:\n");
		  printanswer(hp);
		}
		else {
		  _res.nsaddr_list[0]= addr;
		  _res.nsport_list[0]= htons(NAMESERVER_PORT);
		  printf("Using domain server %s:\n",
			 inet_ntoa(_res.nsaddr));
		}
	      }
	if (strcmp (v[1], ".") == 0)
	  addr = -1;
	else
	  addr = inet_addr(v[1]);
	hp = NULL;
	h_errno = TRY_AGAIN;
/*
 * we handle default domains ourselves, thank you
 */
	_res.options &= ~RES_DEFNAMES;

        if (list)
	  exit(ListHosts(v[1], gettype ? gettype : T_A));
	oldcname = NULL;
	ncnames = 5;
	while (hp == NULL && h_errno == TRY_AGAIN) {
	  if (addr == -1) {
	      cname = NULL;
	      if (oldcname == NULL)
		hp = (struct hostent *)gethostinfo(v[1]);
	      else
		hp = (struct hostent *)gethostinfo((char *)oldcname);
	      if (cname) {
		if (ncnames-- == 0) {
		  printf("Too many cnames.  Possible loop.\n");
		  exit(1);
		}
		oldcname = cname;
		hp = NULL;
		h_errno = TRY_AGAIN;
		continue;
	      }
	  }
	  else {
	    hp = gethostbyaddr((char *)&addr, 4, AF_INET);
	    if (hp)
	      printanswer(hp);
	  }
	  if (!waitmode)
	    break;
	}

	if (hp == NULL) {
	  hperror(h_errno);
	  exit(1);
	}

	exit(0);

}

static int
parsetype(s)
	char *s;
{
if (strcmp(s,"a") == 0)
  return(1);
if (strcmp(s,"ns") == 0)
  return(2);
if (strcmp(s,"md") == 0)
  return(3);
if (strcmp(s,"mf") == 0)
  return(4);
if (strcmp(s,"cname") == 0)
  return(5);
if (strcmp(s,"soa") == 0)
  return(6);
if (strcmp(s,"mb") == 0)
  return(7);
if (strcmp(s,"mg") == 0)
  return(8);
if (strcmp(s,"mr") == 0)
  return(9);
if (strcmp(s,"null") == 0)
  return(10);
if (strcmp(s,"wks") == 0)
  return(11);
if (strcmp(s,"ptr") == 0)
  return(12);
if (strcmp(s,"hinfo") == 0)
  return(13);
if (strcmp(s,"minfo") == 0)
  return(14);
if (strcmp(s,"mx") == 0)
  return(15);
if (strcmp(s,"txt") == 0)	/* Roy */
  return(T_TXT);		/* Roy */
if (strcmp(s,"uinfo") == 0)
  return(100);
if (strcmp(s,"uid") == 0)
  return(101);
if (strcmp(s,"gid") == 0)
  return(102);
if (strcmp(s,"unspec") == 0)
  return(103);
if (strcmp(s,"any") == 0)
  return(255);
if (strcmp(s,"*") == 0)
  return(255);
if (atoi(s))
  return(atoi(s));
fprintf(stderr, "Invalid query type: %s\n", s);
exit(2);
}

static int
parseclass(s)
	char *s;
{
if (strcmp(s,"in") == 0)
  return(C_IN);
if (strcmp(s,"hs") == 0)
  return(C_HS);
if (strcmp(s,"any") == 0)
  return(C_ANY);
if (atoi(s))
  return(atoi(s));
fprintf(stderr, "Invalid query class: %s\n", s);
exit(2);
}

static void
printanswer(hp)
	register struct hostent *hp;
{
	register char **cp;
	register ipaddr_t **hptr;

	printf("Name: %s\n", hp->h_name);
	printf("Address:");
	for (hptr = (ipaddr_t **)hp->h_addr_list; *hptr; hptr++)
	  printf(" %s", inet_ntoa(*(ipaddr_t *)*hptr));
	printf("\nAliases:");
	for (cp = hp->h_aliases; cp && *cp && **cp; cp++)
		printf(" %s", *cp);
	printf("\n\n");
}

static void
hperror(errno) 
int errno;
{
switch(errno) {
	case HOST_NOT_FOUND:
		fprintf(stderr,"Host not found.\n");
		break;
	case TRY_AGAIN:
		fprintf(stderr,"Host not found, try again.\n");
		break;
	case NO_RECOVERY:
		fprintf(stderr,"No recovery, Host not found.\n");
		break;
	case NO_ADDRESS:
		fprintf(stderr,"There is an entry for this host, but it doesn't have an Internet address.\n");
		break;
	}
}


typedef union querybuf {
	dns_hdr_t qb1;
	u8_t qb2[PACKETSZ];
} querybuf_t;

static u8_t hostbuf[BUFSIZ+1];


static int
gethostinfo(name)
	char *name;
{
	register char *cp, **domain;
	int n;
	int hp;
	int nDomain;

	if (strcmp(name, ".") == 0)
		return(getdomaininfo(name, NULL));
	for (cp = name, n = 0; *cp; cp++)
		if (*cp == '.')
			n++;
	if (n && cp[-1] == '.') {
		if (cp[-1] == '.')
			cp[-1] = 0;
		hp = getdomaininfo(name, (char *)NULL);
		if (cp[-1] == 0)
			cp[-1] = '.';
		return (hp);
	}
	if (n == 0 && (cp = __hostalias(name))) {
	        if (verbose)
		    printf("Aliased to \"%s\"\n", cp);
		_res.options |= RES_DEFNAMES;	  
		return (getdomaininfo(cp, (char *)NULL));
	}
#ifdef MAXDS
	for (nDomain = 0;
	     _res.defdname_list[nDomain][0] != 0;
	     nDomain++) {
	    for (domain = _res.dnsrch_list[nDomain]; *domain; domain++) {
	        if (verbose)
		    printf("Trying domain \"%s\"\n", *domain);
		hp = getdomaininfo(name, *domain);
		if (hp)
			return (hp);
	    }
	}
#else
	for (domain = _res.dnsrch; *domain; domain++) {
	  if (verbose)
	    printf("Trying domain \"%s\"\n", *domain);
	  hp = getdomaininfo(name, *domain);
	  if (hp)
	    return (hp);
	}
#endif
	if (h_errno != HOST_NOT_FOUND ||
	   (_res.options & RES_DNSRCH) == 0)
		return (0);
	if (verbose)
	    printf("Trying null domain\n");
	return (getdomaininfo(name, (char *)NULL));
}

static int
getdomaininfo(name, domain)
	char *name, *domain;
{
  int val1, val2;

  if (gettype)
    return getinfo(name, domain, gettype);
  else {
    val1 = getinfo(name, domain, T_A);
    if (cname || verbose)
      return val1;
    val2 = getinfo(name, domain, T_MX);
    return val1 || val2;
  }
}

static int
getinfo(name, domain, type)
	char *name, *domain;
{

	dns_hdr_t *hp;
	u8_t *eom, *bp, *cp;
	querybuf_t buf, answer;
	int n, n1, i, j, nmx, ancount, nscount, arcount, qdcount, buflen;
	u_short pref, class;
	char host[2*MAXDNAME+2];

	if (domain == NULL)
		(void)sprintf(host, "%.*s", MAXDNAME, name);
	else
		(void)sprintf(host, "%.*s.%.*s", MAXDNAME, name, MAXDNAME, domain);

	n = res_mkquery(QUERY, host, getclass, type, (char *)NULL, 0, NULL,
		(char *)&buf, sizeof(buf));
	if (n < 0) {
		if (_res.options & RES_DEBUG)
			printf("res_mkquery failed\n");
		h_errno = NO_RECOVERY;
		return(0);