217ae63218
functions are implimented as wrappers around getservent(), which means it's up to getservent() to do all the work. The NIS support in getservent() only allows it to scan through the services.byname map one entry at a time until it finds the requested service name/port. This can be painfully slow due to the overhead involved (lots and lots of successive RPCs). To fix this, we allow getservbyname() and getservbyport() to signal getservent() that if NIS is turned on (there's a '+' in /etc/services), the usual yp_first()/yp_next() linear search should be abandoned and yp_match() used instead. This causes getservent() to immediately locate the requested entry instead of wasting time groping through the whole map. The downside is that this trick is accomplished by exporting a couple of pointers from getservent.c which getservbyname.c and getservbyport.c can preset in order to tell getservent() what to do. If all three functions were in the same source module, then the extra cruft could be delcared static to avoid poluting the global symbol space. Maybe they should be combined anyway. For now I've settled on prepending lots of underscores.
75 lines
2.5 KiB
C
75 lines
2.5 KiB
C
/*
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* Copyright (c) 1983, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)getservbyport.c 8.1 (Berkeley) 6/4/93";
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#endif /* LIBC_SCCS and not lint */
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#include <netdb.h>
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#include <string.h>
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extern int _serv_stayopen;
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struct servent *
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getservbyport(port, proto)
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int port;
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const char *proto;
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{
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register struct servent *p;
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#ifdef YP
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extern int ___getservbyport_yp;
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extern char *___getservbyproto_yp;
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___getservbyport_yp = port;
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___getservbyproto_yp = (char *)proto;
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#endif
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setservent(_serv_stayopen);
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while (p = getservent()) {
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if (p->s_port != port)
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continue;
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if (proto == 0 || strcmp(p->s_proto, proto) == 0)
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break;
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}
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if (!_serv_stayopen)
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endservent();
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#ifdef YP
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___getservbyport_yp = 0;
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___getservbyproto_yp = NULL;
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#endif
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return (p);
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}
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