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Annotation of fam/fam/ServerHostRef.c++, Revision 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: }