getservice.c

linux下用PCMCIA无线网卡虚拟无线AP的程序源码

/*
** services.c                           /etc/services access functions
**
** This file is part of the NYS Library.
**
** The NYS Library is free software; you can redistribute it and/or
** modify it under the terms of the GNU Library General Public License as
** published by the Free Software Foundation; either version 2 of the
** License, or (at your option) any later version.
**
** The NYS Library is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** Library General Public License for more details.
** 
** You should have received a copy of the GNU Library General Public
** License along with the NYS Library; see the file COPYING.LIB.  If
** not, write to the Free Software Foundation, Inc., 675 Mass Ave,
** Cambridge, MA 02139, USA.
**
**
** Copyright (c) 1983 Regents of the University of California.
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
** 1. Redistributions of source code must retain the above copyright
**    notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
**    notice, this list of conditions and the following disclaimer in the
**    documentation and/or other materials provided with the distribution.
** 3. All advertising materials mentioning features or use of this software
**    must display the following acknowledgement:
**	This product includes software developed by the University of
**	California, Berkeley and its contributors.
** 4. Neither the name of the University nor the names of its contributors
**    may be used to endorse or promote products derived from this software
**    without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
** ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
** OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
** HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
** SUCH DAMAGE.
*/


#define __FORCE_GLIBC__
#include <features.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define	MAXALIASES	35

static FILE *servf = NULL;
static char line[BUFSIZ+1];
static struct servent serv;
static char *serv_aliases[MAXALIASES];
static int serv_stayopen;

void setservent(int f)
{
	if (servf == NULL)
		servf = fopen(_PATH_SERVICES, "r" );
	else
		rewind(servf);
	serv_stayopen |= f;
}

void endservent(void)
{
	if (servf) {
		fclose(servf);
		servf = NULL;
	}
	serv_stayopen = 0;
}

struct servent * getservent(void)
{
	char *p;
	register char *cp, **q;

	if (servf == NULL && (servf = fopen(_PATH_SERVICES, "r" )) == NULL)
		return (NULL);
again:
	if ((p = fgets(line, BUFSIZ, servf)) == NULL)
		return (NULL);
	if (*p == '#')
		goto again;
	cp = strpbrk(p, "#\n");
	if (cp == NULL)
		goto again;
	*cp = '\0';
	serv.s_name = p;
	p = strpbrk(p, " \t");
	if (p == NULL)
		goto again;
	*p++ = '\0';
	while (*p == ' ' || *p == '\t')
		p++;
	cp = strpbrk(p, ",/");
	if (cp == NULL)
		goto again;
	*cp++ = '\0';
	serv.s_port = htons((u_short)atoi(p));
	serv.s_proto = cp;
	q = serv.s_aliases = serv_aliases;
	cp = strpbrk(cp, " \t");
	if (cp != NULL)
		*cp++ = '\0';
	while (cp && *cp) {
		if (*cp == ' ' || *cp == '\t') {
			cp++;
			continue;
		}
		if (q < &serv_aliases[MAXALIASES - 1])
			*q++ = cp;
		cp = strpbrk(cp, " \t");
		if (cp != NULL)
			*cp++ = '\0';
	}
	*q = NULL;
	return (&serv);
}


struct servent *getservbyname(const char *name, const char *proto)
{
	register struct servent *p;
	register char **cp;

	setservent(serv_stayopen);
	while ((p = getservent()) != NULL) {
		if (strcmp(name, p->s_name) == 0)
			goto gotname;
		for (cp = p->s_aliases; *cp; cp++)
			if (strcmp(name, *cp) == 0)
				goto gotname;
		continue;
gotname:
		if (proto == 0 || strcmp(p->s_proto, proto) == 0)
			break;
	}
	if (!serv_stayopen)
		endservent();
	return (p);
}


struct servent * getservbyport(int port, const char *proto)
{
	register struct servent *p;

	setservent(serv_stayopen);
	while ((p = getservent()) != NULL) {
		if (p->s_port != port)
			continue;
		if (proto == 0 || strcmp(p->s_proto, proto) == 0)
			break;
	}
	if (!serv_stayopen)
		endservent();
	return (p);
}