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gethost.c

/*
 * $Xorg: gethost.c,v 1.5 2001/02/09 02:05:38 xorgcvs Exp $
 * $XdotOrg: $
 * 
Copyright 1989, 1998  The Open Group

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from The Open Group.
 * *
 * Author:  Jim Fulton, MIT X Consortium
 */

/* $XFree86: xc/programs/xauth/gethost.c,v 3.20 2003/07/27 12:34:25 herrb Exp $ */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

/* sorry, streams support does not really work yet */
#if defined(STREAMSCONN) && defined(SVR4)
#undef STREAMSCONN
#define TCPCONN
#endif

#ifdef WIN32
#include <X11/Xwinsock.h>
#define EPROTOTYPE WSAEPROTOTYPE
#endif
#include <X11/X.h>
#include <signal.h>
#include <setjmp.h>
#include <ctype.h>
#ifndef __TYPES__
#include <sys/types.h>
#define __TYPES__
#endif
#ifndef WIN32
#ifndef STREAMSCONN
#ifndef Lynx
#include <sys/socket.h>
#else
#include <socket.h>
#endif
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#ifdef HAVE_NET_ERRNO_H
#include <net/errno.h>
#endif /* HAVE_NET_ERRNO_H */
#endif /* !STREAMSCONN */
#endif /* !WIN32 */
#include <errno.h>
#include "xauth.h"

#ifdef DNETCONN
#include <netdnet/dn.h>
#include <netdnet/dnetdb.h>
#endif

#ifndef WIN32
#include <arpa/inet.h>
#endif

#ifdef SIGALRM
static volatile Bool nameserver_timedout = False;


/*
 * get_hostname - Given an internet address, return a name (CHARON.MIT.EDU)
 * or a string representing the address (18.58.0.13) if the name cannot
 * be found.  Stolen from xhost.
 */

static jmp_buf env;
static RETSIGTYPE
nameserver_lost(int sig)
{
  nameserver_timedout = True;
  longjmp (env, -1);
  /* NOTREACHED */
#ifdef SIGNALRETURNSINT
  return -1;                        /* for picky compilers */
#endif
}
#endif

char *
get_hostname (Xauth *auth)
{
    static struct hostent *hp;
    int af;
#ifdef DNETCONN
    struct nodeent *np;
    static char nodeaddr[4 + 2 * DN_MAXADDL];
#endif /* DNETCONN */

    hp = NULL;
    if (auth->address_length == 0)
      return "Illegal Address";
#ifdef TCPCONN
    if (auth->family == FamilyInternet
#if defined(IPv6) && defined(AF_INET6)
      || auth->family == FamilyInternet6
#endif 
      )
    {
#if defined(IPv6) && defined(AF_INET6)
      if (auth->family == FamilyInternet6)
          af = AF_INET6;
      else
#endif
          af = AF_INET;
      if (no_name_lookups == False) {
#ifdef SIGALRM
      /* gethostbyaddr can take a LONG time if the host does not exist.
         Assume that if it does not respond in NAMESERVER_TIMEOUT seconds
         that something is wrong and do not make the user wait.
         gethostbyaddr will continue after a signal, so we have to
         jump out of it. 
         */
      nameserver_timedout = False;
      signal (SIGALRM, nameserver_lost);
      alarm (4);
      if (setjmp(env) == 0) {
#endif
          hp = gethostbyaddr (auth->address, auth->address_length, af);
#ifdef SIGALRM
      }
      alarm (0);
#endif
      }
      if (hp)
        return (hp->h_name);
#if defined(IPv6) && defined(AF_INET6)
      else if (af == AF_INET6) {
        static char addr[INET6_ADDRSTRLEN+2];
        /* Add [] for clarity to distinguish between address & display,
           like RFC 2732 for URL's.  Not required, since X display syntax
           always ends in :<display>, but makes it easier for people to read
           and less confusing to those who expect the RFC 2732 style. */
        addr[0] = '[';
        if (inet_ntop(af, auth->address, addr + 1, INET6_ADDRSTRLEN) == NULL)
          return NULL;
        strcat(addr, "]");
          return addr;
      }
#endif
      else {
        return (inet_ntoa(*((struct in_addr *)(auth->address))));
      }
    }
#endif
#ifdef DNETCONN
    if (auth->family == FamilyDECnet) {
      struct dn_naddr *addr_ptr = (struct dn_naddr *) auth->address;

      if ((no_name_lookups == False) &&
          (np = getnodebyaddr(addr_ptr->a_addr, addr_ptr->a_len, AF_DECnet))) {
          sprintf(nodeaddr, "%s:", np->n_name);
      } else {
          sprintf(nodeaddr, "%s:", dnet_htoa(auth->address));
      }
      return(nodeaddr);
    }
#endif

    return (NULL);
}

#if defined(TCPCONN) && (!defined(IPv6) || !defined(AF_INET6))
/*
 * cribbed from lib/X/XConnDis.c
 */
static Bool 
get_inet_address(char *name, unsigned int *resultp)
{
    unsigned int hostinetaddr = inet_addr (name);
    struct hostent *host_ptr;
    struct sockaddr_in inaddr;            /* dummy variable for size calcs */

#ifndef INADDR_NONE
#define INADDR_NONE -1
#endif

    if (hostinetaddr == INADDR_NONE) {
      if ((host_ptr = gethostbyname (name)) == NULL) {
          /* No such host! */
          errno = EINVAL;
          return False;
      }
      /* Check the address type for an internet host. */
      if (host_ptr->h_addrtype != AF_INET) {
          /* Not an Internet host! */
          errno = EPROTOTYPE;
          return False;
      }
 
      memmove( (char *)&hostinetaddr, (char *)host_ptr->h_addr, 
            sizeof(inaddr.sin_addr));
    }
    *resultp = hostinetaddr;
    return True;
}
#endif

#ifdef DNETCONN
static Bool get_dnet_address (name, resultp)
    char *name;
    struct dn_naddr *resultp;
{
    struct dn_naddr *dnaddrp, dnaddr;
    struct nodeent *np;

    if (dnaddrp = dnet_addr (name)) {     /* stolen from xhost */
      dnaddr = *dnaddrp;
    } else {
      if ((np = getnodebyname (name)) == NULL) return False;
      dnaddr.a_len = np->n_length;
      memmove( dnaddr.a_addr, np->n_addr, np->n_length);
    }
    *resultp = dnaddr;
    return True;
}
#endif

struct addrlist *get_address_info (
    int family,
    char *fulldpyname,
    int prefix,
    char *host)
{
    struct addrlist *retval = NULL;
    int len = 0;
    void *src = NULL;
#ifdef TCPCONN
#if defined(IPv6) && defined(AF_INET6)
    struct addrlist *lastrv = NULL;
    struct addrinfo *firstai = NULL;
    struct addrinfo *ai = NULL;
    struct addrinfo hints;
#else
    unsigned int hostinetaddr;
#endif
#endif
#ifdef DNETCONN
    struct dn_naddr dnaddr;
#endif
    char buf[255];

    /*
     * based on the family, set the pointer src to the start of the address
     * information to be copied and set len to the number of bytes.
     */
    switch (family) {
      case FamilyLocal:             /* hostname/unix:0 */
                              /* handle unix:0 and :0 specially */
      if (prefix == 0 && (strncmp (fulldpyname, "unix:", 5) == 0 ||
                      fulldpyname[0] == ':')) {

          if (!get_local_hostname (buf, sizeof buf)) {
            len = 0;
          } else {
            src = buf;
            len = strlen (buf);
          }
      } else {
          src = fulldpyname;
          len = prefix;
      }
      break;
      case FamilyInternet:          /* host:0 */
#ifdef TCPCONN
#if defined(IPv6) && defined(AF_INET6)
      case FamilyInternet6:
      memset(&hints, 0, sizeof(hints));
      hints.ai_family = PF_UNSPEC; /* IPv4 or IPv6 */
      hints.ai_socktype = SOCK_STREAM; /* only interested in TCP */
      hints.ai_protocol = 0;  
        if (getaddrinfo(host,NULL,&hints,&firstai) !=0) return NULL;
      for (ai = firstai; ai != NULL; ai = ai->ai_next) {
          if (ai->ai_family == AF_INET) {
            struct sockaddr_in *sin = (struct sockaddr_in *)ai->ai_addr;
            src = &(sin->sin_addr);
            len = sizeof(sin->sin_addr);
            family = FamilyInternet;
          } else if (ai->ai_family == AF_INET6) {
            struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)ai->ai_addr;
            src = &(sin6->sin6_addr);
            len = sizeof(sin6->sin6_addr);
            family = FamilyInternet6;
          }

          if (len > 0 && src != NULL) {
            struct addrlist *newrv = malloc (sizeof(struct addrlist));
            if (newrv) {
                newrv->address = malloc (len);
                if (newrv->address) {
                  memcpy(newrv->address, src, len);
                  newrv->next = NULL;
                  newrv->family = family;
                  newrv->len = len;
                  if (retval == NULL) {
                      lastrv = retval = newrv;
                  } else {
                      lastrv->next = newrv;
                      lastrv = newrv;
                  }
                } else {
                  free(newrv);
                }
            }
          }
          /* reset to avoid copying into list twice */
          len = 0;
          src = NULL;
      }
      freeaddrinfo(firstai);
      break;
#else
      if (!get_inet_address (host, &hostinetaddr)) return NULL;
      src = (char *) &hostinetaddr;
      len = 4; /* sizeof inaddr.sin_addr, would fail on Cray */
      break;
#endif /* IPv6 */
#else
      return NULL;
#endif
      case FamilyDECnet:            /* host::0 */
#ifdef DNETCONN
      if (!get_dnet_address (host, &dnaddr)) return NULL;
      src = (char *) &dnaddr;
      len = (sizeof dnaddr);
      break;
#else
      /* fall through since we don't have code for it */
#endif
      default:
      src = NULL;
      len = 0;
    }

    /*
     * if source was provided, allocate space and copy it
     */
    if (len > 0 && src != NULL) {
      retval = malloc (sizeof(struct addrlist));
      if (retval) {
          retval->address = malloc (len);
          if (retval->address) {
            memcpy(retval->address, src, len);
            retval->next = NULL;
            retval->family = family;
            retval->len = len;
          } else {
            free(retval);
            retval = NULL;
          }
      }
    }
    return retval;
}

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