gethostent.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static	char	*sccsid = "@(#)gethostent.c	4.6	(ULTRIX)	2/12/91";
#endif lint
/************************************************************************
 *									*
 *			Copyright (c) 1984-1989 by			*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/
/****************************************************************
 *								*
 *  Licensed to Digital Equipment Corporation, Maynard, MA	*
 *		Copyright 1985 Sun Microsystems, Inc.		*
 *			All rights reserved.			*
 *								*
 ****************************************************************/

/*
 * Modification History:
 *
 * 15-Nov-90    lebel
 *	Fixed strfind.
 *
 * 07-Feb-90	sue
 *	Remove calls to remove_local_domain().  This does not conform
 *	to standard BIND semantics.  Change the name of the routine and
 *	function to local_hostname_length which returns the length of 
 *	the short hostname if the string contains the local domain 
 *	name.
 *
 * 13-Nov-89	sue
 *	Changed svc_gethostflag initial value to -2 and now perform a
 *	check in gethostent to see if the sethostent has been called yet.
 *
 * 18-Aug-89	sue
 *	Added support for gethostent_bind().  It depends on the BIND
 *	host database being built by /var/dss/namedb/bin/make_hosts.
 *	Removed call to remove_local_domain in interpret().  It does
 *	not make sense to modify the answer without modifying the
 *	request.  The user should get what he asks for.
 *
 * 24-Jul-89	logcher
 *	Removed generic sethostent and endhostent calls from generic
 *	gethostbyname and gethostbyaddr.  Added the specific set and end
 *	calls in the specific get routines.  Moved remove_local_domain
 *	call in interpret to after nulls have been placed.
 *
 * 25-May-89	logcher
 *	Changed name of any() to getcommon_any().
 *
 * 16-May-89	logcher
 *	Remove all of the "svc" specific code and put in separate
 *	file, svcent.c,  so other get*ent.c routines can use them.
 *	Removed static declarations on *_[local|yp|bind] calls so 
 *	that these routines can be called outside of this file.
 *
 * 09-May-89	logcher
 *	Added remove_local_domain to strip off local domain from name,
 *	if it exists.  Changed FSG debug lines to DEBUG.
 *
 * 15-Jul-88	logcher
 *	In init_svcorder, do an fclose on the file descriptor for
 *	the /etc/svcorder.
 *
 * 07-Mar-88	rglaser
 *	Merge Fred's changes into the latest version from Berkeley.
 *	Change debug printouts to go to stderr for better daemon debug.
 *
 * 24-Feb-88    fglover
 *	Support entries in /etc/svcorder file as case insensitive,
 *	but map to upper case for internal comparisons.  Define
 *	macro L_TO_U to do the mapping.
 *
 * 26-Jan-88	logcher
 *	Added a few more BIND 4.7.3 changes as well as changing
 *	some ifdefed debug messages to print on the console to be 
 *	useful if compiled in daemons (rshd).
 *
 */

#include <stdio.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <ctype.h>
#include <netdb.h>
#include <errno.h>
#include <rpcsvc/ypclnt.h>
#include <sys/stat.h>

#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <resolv.h>
#include <sys/svcinfo.h>

#if defined(lint) && !defined(DEBUG)
#define DEBUG
#endif

/*
 * Internet version.
 */

#define	MAXALIASES	35
#define MAXADDRS	35
#define	MAXADDRSIZE	14

static char HOSTDB[] = "/etc/hosts";
static struct hostent host;
static struct in_addr host_addr;
static char *h_addr_ptrs[MAXADDRS+1];
static char *host_aliases[MAXALIASES];
static char hostbuf[BUFSIZ+1];
static FILE *hostf = NULL;
static char line[BUFSIZ+1];
static char hostaddr[MAXADDRS];
static char *host_addrs[2];
static int stayopen=0;
static char *current = NULL;	/* current entry, analogous to hostf */
static int currentlen;
static struct svcinfo *svcinfo;
static char *domain;

static struct hostent *interpret();
static struct hostent *getanswer();
static struct hostent *gethostdomain();
char *hostalias();
char *inet_ntoa();
char *strfind();
char *getcommon_any();
char *yellowup();

int h_errno;
extern errno;

#if PACKETSZ > 1024
#define MAXPACKET       PACKETSZ
#else
#define MAXPACKET       1024
#endif

typedef union {
    HEADER qb1;
    char qb2[MAXPACKET];
} querybuf;

static union {
    long al;
    char ac;
} align;
int svc_gethostflag = -2;
int svc_gethostbind;

/* NOTE: _local versions of these are available in gethostent_local.c.
 * Keep these static to avoid conflicts
 */
static int sethostent_local();
static int endhostent_local();
static struct hostent *gethostent_local();
static struct hostent *gethostbyaddr_local(); 
static struct hostent *gethostbyname_local();

int setent_bind();
int sethostent_yp();
int endent_bind();
int endhostent_yp();
struct hostent *gethostent_bind();
struct hostent *gethostent_yp();
struct hostent *gethostbyaddr_bind(); 
struct hostent *gethostbyaddr_yp(); 
struct hostent *gethostbyname_bind();	
struct hostent *gethostbyname_yp();

/* 
 *	call service routines indirectly
 */

static int	(*sethostents []) ()={
		sethostent_local,
		sethostent_yp,
		setent_bind
};
static int	(*endhostents []) ()={
		endhostent_local,
		endhostent_yp,
		endent_bind
};
static struct hostent * (*gethostents []) ()={
		gethostent_local,
		gethostent_yp,
		gethostent_bind
};
static struct hostent * (*gethostaddrs []) ()={
		gethostbyaddr_local,
		gethostbyaddr_yp,
		gethostbyaddr_bind
};
static struct hostent * (*gethostnames []) ()={
		gethostbyname_local,
		gethostbyname_yp,
		gethostbyname_bind
};


/*
 * generic gethost service routines
 */

sethostent (f)
	int f;
{
	register i;

	svc_gethostflag = -1;
	svc_gethostbind = 0;
	if ((svcinfo = getsvc()) != NULL)
		for (i=0; (svc_lastlookup = svcinfo->svcpath[SVC_HOSTS][i]) != SVC_LAST; i++)
			(*(sethostents [svcinfo->svcpath[SVC_HOSTS][i]])) (f);
}

endhostent ()
{
	register i;

	svc_gethostflag = -1;
	svc_gethostbind = 0;
	if ((svcinfo = getsvc()) != NULL)
		for (i=0; (svc_lastlookup = svcinfo->svcpath[SVC_HOSTS][i]) != SVC_LAST; i++)
			(*(endhostents [svcinfo->svcpath[SVC_HOSTS][i]])) ();
}

struct hostent *
gethostent()
{
	register struct hostent *p=NULL;
	register i;

	/*
	 * Check if sethostent was not made yet
	 */
	if (svc_gethostflag == -2)
		sethostent(0);
	/*
	 * Check if this is the first time through gethostent
	 */
	if (svc_gethostflag == -1) {
		/*
		 * If it is, init the svcinfo structure
		 */
		if ((svcinfo = getsvc()) == NULL)
			return((struct hostent *)NULL);
		i = 0;
	}
	else {
		/*
		 * If it is not, set the index to the last used one
		 */
		i = svc_gethostflag;
	}
	for (; (svc_lastlookup = svcinfo->svcpath[SVC_HOSTS][i]) != SVC_LAST; i++)
		if (p = ((*(gethostents [svcinfo->svcpath[SVC_HOSTS][i]])) () )) {
			svc_gethostflag = i;
			break;
		}
	return (p);
}

struct hostent *
gethostbyname (name)
	register char *name;
{
	register struct hostent *p=NULL;
	register i;

	/* avoid null pointer de-reference on mips */
	if (name == 0)
		return(0);
	if ((svcinfo = getsvc()) != NULL)
		for (i=0; (svc_lastlookup = svcinfo->svcpath[SVC_HOSTS][i]) != SVC_LAST; i++)
			if (p = ((*(gethostnames [svcinfo->svcpath[SVC_HOSTS][i]])) (name) ))
				break;
	return (p);
}

struct hostent *
gethostbyaddr (addr, len, type)
	register char *addr;
	register int len, type;
{
	register struct hostent *p=NULL;
	register i;

	if ((svcinfo = getsvc()) != NULL)
		for (i=0; (svc_lastlookup = svcinfo->svcpath[SVC_HOSTS][i]) != SVC_LAST; i++)
			if (p = ((*(gethostaddrs [svcinfo->svcpath[SVC_HOSTS][i]])) (addr, len, type) ))
				break;
	return (p);
}

/*
 * specific gethost service routines
 */

static struct hostent *
gethostbyaddr_local(addr, len, type)
	char *addr;
	register int len, type;
{
	register struct hostent *p=NULL;

#ifdef DEBUG
	fprintf(stderr, "gethostbyaddr_local(%d.%d.%d.%d, %d, %d)\n", addr[0], addr[1], addr[2], addr[3], len, type);
#endif DEBUG
	sethostent_local(0);
	while (p = gethostent_local()) {
		if (p->h_addrtype != type || p->h_length != len)
			continue;
		if (bcmp(p->h_addr, addr, len) == 0)
			break;
	}
	endhostent_local();
	return (p);
}

struct hostent *
gethostbyaddr_bind(addr, len, type)
	char *addr;
	register int len, type;
{
	int n;
	querybuf buf;
	register struct hostent *hp;
	char qbuf[MAXDNAME];

#ifdef DEBUG
	fprintf(stderr, "gethostbyaddr_bind(%d.%d.%d.%d, %d, %d)\n", addr[0], addr[1], addr[2], addr[3], len, type);
#endif DEBUG
	if (type != AF_INET)
		return (NULL);
	setent_bind(0);
	(void)sprintf(qbuf, "%d.%d.%d.%d.in-addr.arpa",
		((unsigned)addr[3] & 0xff),
		((unsigned)addr[2] & 0xff),
		((unsigned)addr[1] & 0xff),
		((unsigned)addr[0] & 0xff));
	n = res_mkquery(QUERY, qbuf, C_IN, T_PTR, (char *)NULL, 0, NULL,
		(char *)&buf, sizeof(buf));
	if (n < 0) {
#ifdef DEBUG
		if (_res.options & RES_DEBUG)
			fprintf(stderr,"res_mkquery failed\n");
#endif
		endent_bind();
		return ((struct hostent *)NULL);
	}
	hp = getanswer((char *)&buf, n, 1);
	if (hp == NULL && errno == ECONNREFUSED) {
		endent_bind();
		return((struct hostent *)NULL);	
	}
	if (hp == NULL) {
		endent_bind();
		return((struct hostent *)NULL);	
	}
	hp->h_addrtype = type;
	hp->h_length = len;
	h_addr_ptrs[0] = (char *)&host_addr;
	h_addr_ptrs[1] = (char *)0;
	host_addr = *(struct in_addr *)addr;
	endent_bind();
	return(hp);
}

struct hostent *
gethostbyaddr_yp(addr, len, type)
	char *addr;
	register int len, type;
{
	register struct hostent *p=NULL;
	int reason;
	char *adrstr, *val = NULL;
	int vallen = 0;

#ifdef DEBUG
	fprintf(stderr, "gethostbyaddr_yp(%d.%d.%d.%d, %d, %d)\n", addr[0], addr[1], addr[2], addr[3], len, type);
#endif DEBUG
	sethostent_yp(0);
	if ((domain = yellowup(0)) == NULL)
		return (gethostbyaddr_local(addr, len, type));
	adrstr = inet_ntoa(*(int *)addr);
	if (reason = yp_match(domain, "hosts.byaddr", adrstr, strlen(adrstr), &val, &vallen)) {
#ifdef DEBUG
		fprintf(stderr, "reason yp_first failed is %d\n", reason);
#endif
		p = NULL;
	}
	else {
		p = interpret(val, vallen, SVC_YP);
		free(val);
	}
	endhostent_yp();
	return (p);
}

static struct hostent *
gethostbyname_local(name)
	register char *name;
{
	register struct hostent *p=NULL;
	register char **cp;

#ifdef DEBUG
	fprintf(stderr, "gethostbyname_local(%s)\n", name);
#endif DEBUG
	sethostent_local(0);
	while (p = gethostent_local()) {
		if (strcmp(p->h_name, name) == 0)
			break;
		for (cp = p->h_aliases; *cp != 0; cp++)
			if (strcmp(*cp, name) == 0)
				goto found;
	}
found:
	endhostent_local();
	return (p);
}

struct hostent *
gethostbyname_bind(name)
	register char *name;
{
	register char *cp, **domain;
	int n;
	struct hostent *hp, *gethostdomain();

#ifdef DEBUG
	fprintf(stderr, "gethostbyname_bind(%s)\n", name);
#endif DEBUG
	if (!(_res.options & RES_INIT) && res_init() == -1)
		return (NULL);
	setent_bind(0);
	/*
	 * disallow names consisting only of digits/dots, unless
	 * they end in a dot.
	 */
	if (isdigit(name[0]))
		for (cp = name;; ++cp) {
			if (!*cp) {
				if (*--cp == '.')
					break;
				h_errno = HOST_NOT_FOUND;
				endent_bind();
				return ((struct hostent *) NULL);
			}
			if (!isdigit(*cp) && *cp != '.') 
				break;
		}
	errno = 0;
	for (cp = name, n = 0; *cp; cp++)
		if (*cp == '.')
			n++;

	if (n == 0 && (cp = hostalias(name))) {
		endent_bind();
		return (gethostdomain(cp, (char *)NULL));
	}
	if ((n == 0 || *--cp != '.') && (_res.options & RES_DEFNAMES))
	    for (domain = _res.dnsrch; *domain; domain++) {
		hp = gethostdomain(name, *domain);
		if (hp) {
			endent_bind();
			return (hp);
		}
		/*
		 * If no server present, use host table.
		 * If host isn't found in this domain,
		 * keep trying higher domains in the search list
		 * (if that's enabled).
		 * On a NO_ADDRESS error, keep trying, otherwise
		 * a wildcard MX entry could keep us from finding
		 * host entries higher in the domain.
		 * If we get some other error (non-authoritative negative
		 * answer or server failure), then stop searching up,
		 * but try the input name below in case it's fully-qualified.
		 */
		if (errno == ECONNREFUSED) {
			endent_bind();
			return ((struct hostent *)NULL);
		}
		if ((h_errno != HOST_NOT_FOUND && h_errno != NO_ADDRESS) ||
		    (_res.options & RES_DNSRCH) == 0)
			break;
		h_errno = 0;
	}
	/*
	 * If the search/default failed, try the name as fully-qualified,
	 * but only if it contained at least one dot (even trailing).
	 */
	if (n) {
		endent_bind();
		return (gethostdomain(name, (char *)NULL));
	}
	endent_bind();
	return ((struct hostent *) NULL);
}

struct hostent *
gethostbyname_yp(name)
	register char *name;
{
	register struct hostent *p=NULL;
	int reason;
	char *val = NULL;
	int vallen = 0;