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Annotation of fam/fam/ServerHostRef.c++, Revision 1.1.1.1

1.1       trev        1: //  Copyright (C) 1999 Silicon Graphics, Inc.  All Rights Reserved.
                      2: //
                      3: //  This program is free software; you can redistribute it and/or modify it
                      4: //  under the terms of version 2 of the GNU General Public License as
                      5: //  published by the Free Software Foundation.
                      6: //
                      7: //  This program is distributed in the hope that it would be useful, but
                      8: //  WITHOUT ANY WARRANTY; without even the implied warranty of
                      9: //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  Further, any
                     10: //  license provided herein, whether implied or otherwise, is limited to
                     11: //  this program in accordance with the express provisions of the GNU
                     12: //  General Public License.  Patent licenses, if any, provided herein do not
                     13: //  apply to combinations of this program with other product or programs, or
                     14: //  any other product whatsoever.  This program is distributed without any
                     15: //  warranty that the program is delivered free of the rightful claim of any
                     16: //  third person by way of infringement or the like.  See the GNU General
                     17: //  Public License for more details.
                     18: //
                     19: //  You should have received a copy of the GNU General Public License along
                     20: //  with this program; if not, write the Free Software Foundation, Inc., 59
                     21: //  Temple Place - Suite 330, Boston MA 02111-1307, USA.
                     22:
                     23: #include "ServerHostRef.h"
                     24:
                     25: #include <assert.h>
                     26: #include <netdb.h>
                     27:
                     28: unsigned int		   ServerHostRef::count;
                     29: StringTable<ServerHost *> *ServerHostRef::hosts_by_name;
                     30:
                     31: ///////////////////////////////////////////////////////////////////////////////
                     32: //  ServerHostRef methods simply maintain refcounts on ServerHosts.
                     33:
                     34: ServerHostRef&
                     35: ServerHostRef::operator = (const ServerHostRef& that)
                     36: {
                     37:     if (this != &that)
                     38:     {
                     39: 	if (p && !--p->refcount)
                     40: 	    delete p;
                     41: 	p = that.p;
                     42: 	if (p)
                     43: 	    p->refcount++;
                     44:     }
                     45:     return *this;
                     46: }
                     47:
                     48: ServerHostRef::~ServerHostRef()
                     49: {
                     50:     if (!--p->refcount)
                     51:     {
                     52: 	// Remove from hosts_by_name.
                     53:
                     54: 	const char *name;
                     55: 	for (unsigned i = 0; ((name = hosts_by_name->key(i)) != NULL); )
                     56: 	    if (hosts_by_name->value(i) == p)
                     57: 		hosts_by_name->remove(name);
                     58: 	    else
                     59: 		i++;
                     60:
                     61: 	delete p;
                     62:     }
                     63:
                     64:     // When the last reference is gone, delete hosts_by_name.
                     65:
                     66:     if (!--count && hosts_by_name)
                     67:     {	assert(!hosts_by_name->size());
                     68: 	delete hosts_by_name;
                     69: 	hosts_by_name = NULL;
                     70:     }
                     71: }
                     72:
                     73: ServerHost *
                     74: ServerHostRef::find(const char *name)
                     75: {
                     76:     //  Create hosts_by_name first time.
                     77:
                     78:     if (!hosts_by_name)
                     79: 	hosts_by_name = new StringTable<ServerHost *>;
                     80:
                     81:     //  Look in list of existing hosts.
                     82:
                     83:     ServerHost *host = hosts_by_name->find(name);
                     84:     if (host)
                     85: 	return host;
                     86:
                     87:     //  Look up hostname via gethostbyname().
                     88:
                     89:     hostent *hp = gethostbyname(name);
                     90:     char *fake_haliases[1];
                     91:     in_addr fake_haddr;
                     92:     in_addr *fake_haddrlist[2];
                     93:     hostent fake_hostent;
                     94:
                     95:     if (!hp)
                     96:     {
                     97: 	//  gethostbyname() failed for some reason (e.g., ypbind
                     98: 	//  is down or NIS map just changed, ethernet came unplugged,
                     99: 	//  or something equally tragic).
                    100: 	//
                    101: 	//  Fake it by building a hostent with an illegal address.
                    102:
                    103: 	fake_haliases[0] = NULL;
                    104: 	fake_haddr.s_addr = 0;
                    105: 	fake_haddrlist[0] = &fake_haddr;
                    106: 	fake_haddrlist[1] = NULL;
                    107: 	fake_hostent.h_name = (char *) name;
                    108: 	fake_hostent.h_aliases = fake_haliases;
                    109: 	fake_hostent.h_addrtype = 0;
                    110: 	fake_hostent.h_length = sizeof fake_haddr;
                    111: 	fake_hostent.h_addr_list = (char **) fake_haddrlist;
                    112: 	hp = &fake_hostent;
                    113:     }
                    114:
                    115:     assert(hp->h_length == sizeof (struct in_addr));
                    116:
                    117:     //  Create new host.
                    118:
                    119:     host = new ServerHost(*hp);
                    120:
                    121:     //  Add this host to hosts_by_name.
                    122:
                    123:     hosts_by_name->insert(name, host);
                    124:     hosts_by_name->insert(hp->h_name, host);
                    125:     for (char *const*p = hp->h_aliases; *p; p++)
                    126: 	hosts_by_name->insert(*p, host);
                    127:
                    128:     return host;
                    129: }