text: /* $XConsortium: AuGetBest.c /main/23 1996/12/04 11:04:55 lehors $ */
  
  /*
  
  Copyright (c) 1988  X Consortium
  
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
  
  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
  X CONSORTIUM 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 X Consortium 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 X Consortium.
  
  */
  
  #include <X11/Xauth.h>
  #include <X11/Xos.h>
  #ifdef XTHREADS
  #include <X11/Xthreads.h>
  #endif
  #ifdef hpux
  #define X_INCLUDE_NETDB_H
  #define XOS_USE_NO_LOCKING
  #include <X11/Xos_r.h>
  #endif
  
  static
  binaryEqual (a, b, len)
  register char	*a, *b;
  register int	len;
  {
      while (len--)
  	if (*a++ != *b++)
  	    return 0;
      return 1;
  }
  
  #if NeedFunctionPrototypes
  Xauth *
  XauGetBestAuthByAddr (
  #if NeedWidePrototypes
      unsigned int	family,
      unsigned int	address_length,
  #else
      unsigned short	family,
      unsigned short	address_length,
  #endif
      _Xconst char*	address,
  #if NeedWidePrototypes
      unsigned int	number_length,
  #else
      unsigned short	number_length,
  #endif
      _Xconst char*	number,
      int			types_length,
      char**		types,
      _Xconst int*	type_lengths)
  #else
  Xauth *
  XauGetBestAuthByAddr (family, address_length, address,
  			  number_length, number,
  			  types_length, types, type_lengths)
      unsigned short	family;
      unsigned short	address_length;
      char		*address;
      unsigned short	number_length;
      char		*number;
      int			types_length;
      char		**types;
      int			*type_lengths;
  #endif
  {
      FILE    *auth_file;
      char    *auth_name;
      Xauth   *entry;
      Xauth   *best;
      int	    best_type;
      int	    type;
  #ifdef hpux
      char		*fully_qual_address;
      unsigned short	fully_qual_address_length;
  #endif
  
      auth_name = XauFileName ();
      if (!auth_name)
  	return 0;
      if (access (auth_name, R_OK) != 0)		/* checks REAL id */
  	return 0;
      auth_file = fopen (auth_name, "rb");
      if (!auth_file)
  	return 0;
  
  #ifdef hpux
      if (family == FamilyLocal) {
  	_Xgethostbynameparams hparams;
  	struct hostent *hostp;
  
  	/* make sure we try fully-qualified hostname */
  	if ((hostp = _XGethostbyname(address,hparams)) != NULL) {
  	    fully_qual_address = hostp->h_name;
  	    fully_qual_address_length = strlen(fully_qual_address);
  	}
  	else
  	{
  	    fully_qual_address = NULL;
  	    fully_qual_address_length = 0;
  	}
      }
  #endif /* hpux */
  
      best = 0;
      best_type = types_length;
      for (;;) {
  	entry = XauReadAuth (auth_file);
  	if (!entry)
  	    break;
  	/*
  	 * Match when:
  	 *   either family or entry->family are FamilyWild or
  	 *    family and entry->family are the same
  	 *  and
  	 *   either address or entry->address are empty or
  	 *    address and entry->address are the same
  	 *  and
  	 *   either number or entry->number are empty or
  	 *    number and entry->number are the same
  	 *  and
  	 *   name matches one of the specified names, or no names
  	 *    were specified
  	 */
  
  	if ((family == FamilyWild || entry->family == FamilyWild ||
  	     (entry->family == family &&
  	     ((address_length == entry->address_length &&
  	      binaryEqual (entry->address, address, (int)address_length))
  #ifdef hpux
  	     || (family == FamilyLocal &&
  		fully_qual_address_length == entry->address_length &&
  	     	binaryEqual (entry->address, fully_qual_address,
  		    (int) fully_qual_address_length))
  #endif
  	    ))) &&
  	    (number_length == 0 || entry->number_length == 0 ||
  	     (number_length == entry->number_length &&
  	      binaryEqual (entry->number, number, (int)number_length))))
  	{
  	    if (best_type == 0)
  	    {
  		best = entry;
  		break;
  	    }
  	    for (type = 0; type < best_type; type++)
  		if (type_lengths[type] == entry->name_length &&
  		    !(strncmp (types[type], entry->name, entry->name_length)))
  		{
  		    break;
  		}
  	    if (type < best_type)
  	    {
  		if (best)
  		    XauDisposeAuth (best);
  		best = entry;
  		best_type = type;
  		if (type == 0)
  		    break;
  		continue;
  	    }
  	}
  	XauDisposeAuth (entry);
      }
      (void) fclose (auth_file);
      return best;
  }
  