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yplib.c revision 1.28 
      1 /*	$NetBSD: yplib.c,v 1.28 1997/07/07 02:00:43 lukem Exp $	 */
      2 
      3 /*
      4  * Copyright (c) 1992, 1993 Theo de Raadt <deraadt (at) fsa.ca>
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by Theo de Raadt.
     18  * 4. The name of the author may not be used to endorse or promote products
     19  *    derived from this software without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     22  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     23  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
     25  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #if defined(LIBC_SCCS) && !defined(lint)
     35 static char rcsid[] = "$NetBSD: yplib.c,v 1.28 1997/07/07 02:00:43 lukem Exp $";
     36 #endif
     37 
     38 #include <sys/param.h>
     39 #include <sys/types.h>
     40 #include <sys/socket.h>
     41 #include <sys/file.h>
     42 #include <sys/uio.h>
     43 #include <arpa/nameser.h>
     44 #include <errno.h>
     45 #include <stdio.h>
     46 #include <stdlib.h>
     47 #include <string.h>
     48 #include <unistd.h>
     49 #include <rpc/rpc.h>
     50 #include <rpc/xdr.h>
     51 #include <rpcsvc/yp_prot.h>
     52 #include <rpcsvc/ypclnt.h>
     53 
     54 #define BINDINGDIR	"/var/yp/binding"
     55 #define YPBINDLOCK	"/var/run/ypbind.lock"
     56 
     57 struct dom_binding *_ypbindlist;
     58 char _yp_domain[MAXHOSTNAMELEN];
     59 
     60 #define YPLIB_TIMEOUT		10
     61 #define YPLIB_RPC_RETRIES	4
     62 
     63 struct timeval _yplib_timeout = { YPLIB_TIMEOUT, 0 };
     64 struct timeval _yplib_rpc_timeout = { YPLIB_TIMEOUT / YPLIB_RPC_RETRIES,
     65 	1000000 * (YPLIB_TIMEOUT % YPLIB_RPC_RETRIES) / YPLIB_RPC_RETRIES };
     66 int _yplib_nerrs = 5;
     67 
     68 void	_yp_unbind __P((struct dom_binding *));
     69 int	_yp_invalid_domain __P((const char *));
     70 
     71 int
     72 _yp_dobind(dom, ypdb)
     73 	const char     *dom;
     74 	struct dom_binding **ypdb;
     75 {
     76 	static int      pid = -1;
     77 	char            path[MAXPATHLEN];
     78 	struct dom_binding *ysd, *ysd2;
     79 	struct ypbind_resp ypbr;
     80 	struct sockaddr_in clnt_sin;
     81 	int             clnt_sock, fd, gpid;
     82 	CLIENT         *client;
     83 	int             new = 0, r;
     84 	int             nerrs = 0;
     85 
     86 	if (dom == NULL || *dom == '\0')
     87 		return YPERR_BADARGS;
     88 
     89 	/*
     90 	 * test if YP is running or not
     91 	 */
     92 	if ((fd = open(YPBINDLOCK, O_RDONLY)) == -1)
     93 		return YPERR_YPBIND;
     94 	if (!(flock(fd, LOCK_EX | LOCK_NB) == -1 && errno == EWOULDBLOCK)) {
     95 		(void)close(fd);
     96 		return YPERR_YPBIND;
     97 	}
     98 	(void)close(fd);
     99 
    100 	gpid = getpid();
    101 	if (!(pid == -1 || pid == gpid)) {
    102 		ysd = _ypbindlist;
    103 		while (ysd) {
    104 			if (ysd->dom_client)
    105 				clnt_destroy(ysd->dom_client);
    106 			ysd2 = ysd->dom_pnext;
    107 			free(ysd);
    108 			ysd = ysd2;
    109 		}
    110 		_ypbindlist = NULL;
    111 	}
    112 	pid = gpid;
    113 
    114 	if (ypdb != NULL)
    115 		*ypdb = NULL;
    116 
    117 	for (ysd = _ypbindlist; ysd; ysd = ysd->dom_pnext)
    118 		if (strcmp(dom, ysd->dom_domain) == 0)
    119 			break;
    120 	if (ysd == NULL) {
    121 		if ((ysd = malloc(sizeof *ysd)) == NULL)
    122 			return YPERR_YPERR;
    123 		(void)memset(ysd, 0, sizeof *ysd);
    124 		ysd->dom_socket = -1;
    125 		ysd->dom_vers = 0;
    126 		new = 1;
    127 	}
    128 again:
    129 	if (ysd->dom_vers == 0) {
    130 		(void) snprintf(path, sizeof(path), "%s/%s.%d",
    131 				BINDINGDIR, dom, 2);
    132 		if ((fd = open(path, O_RDONLY)) == -1) {
    133 			/*
    134 			 * no binding file, YP is dead, or not yet fully
    135 			 * alive.
    136 			 */
    137 			goto trynet;
    138 		}
    139 		if (flock(fd, LOCK_EX | LOCK_NB) == -1 &&
    140 		    errno == EWOULDBLOCK) {
    141 			struct iovec    iov[2];
    142 			struct ypbind_resp ybr;
    143 			u_short         ypb_port;
    144 			struct ypbind_binding *bn;
    145 
    146 			iov[0].iov_base = (caddr_t) & ypb_port;
    147 			iov[0].iov_len = sizeof ypb_port;
    148 			iov[1].iov_base = (caddr_t) & ybr;
    149 			iov[1].iov_len = sizeof ybr;
    150 
    151 			r = readv(fd, iov, 2);
    152 			if (r != iov[0].iov_len + iov[1].iov_len) {
    153 				(void)close(fd);
    154 				ysd->dom_vers = -1;
    155 				goto again;
    156 			}
    157 			(void)memset(&ysd->dom_server_addr, 0,
    158 				     sizeof ysd->dom_server_addr);
    159 			ysd->dom_server_addr.sin_len =
    160 				sizeof(struct sockaddr_in);
    161 			ysd->dom_server_addr.sin_family = AF_INET;
    162 			bn = &ybr.ypbind_respbody.ypbind_bindinfo;
    163 			ysd->dom_server_addr.sin_port =
    164 				bn->ypbind_binding_port;
    165 
    166 			ysd->dom_server_addr.sin_addr =
    167 				bn->ypbind_binding_addr;
    168 
    169 			ysd->dom_server_port = ysd->dom_server_addr.sin_port;
    170 			(void)close(fd);
    171 			goto gotit;
    172 		} else {
    173 			/* no lock on binding file, YP is dead. */
    174 			(void)close(fd);
    175 			if (new)
    176 				free(ysd);
    177 			return YPERR_YPBIND;
    178 		}
    179 	}
    180 trynet:
    181 	if (ysd->dom_vers == -1 || ysd->dom_vers == 0) {
    182 		struct ypbind_binding *bn;
    183 		(void)memset(&clnt_sin, 0, sizeof clnt_sin);
    184 		clnt_sin.sin_len = sizeof(struct sockaddr_in);
    185 		clnt_sin.sin_family = AF_INET;
    186 		clnt_sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
    187 
    188 		clnt_sock = RPC_ANYSOCK;
    189 		client = clnttcp_create(&clnt_sin, YPBINDPROG, YPBINDVERS,
    190 					&clnt_sock, 0, 0);
    191 		if (client == NULL) {
    192 			clnt_pcreateerror("clnttcp_create");
    193 			if (new)
    194 				free(ysd);
    195 			return YPERR_YPBIND;
    196 		}
    197 		r = clnt_call(client, YPBINDPROC_DOMAIN,
    198 		    xdr_ypdomain_wrap_string, &dom, xdr_ypbind_resp,
    199 		    &ypbr, _yplib_timeout);
    200 		if (r != RPC_SUCCESS) {
    201 			if (new == 0 && ++nerrs == _yplib_nerrs) {
    202 				nerrs = 0;
    203 				fprintf(stderr,
    204 		    "YP server for domain %s not responding, still trying\n",
    205 				    dom);
    206 			}
    207 			clnt_destroy(client);
    208 			ysd->dom_vers = -1;
    209 			goto again;
    210 		}
    211 		clnt_destroy(client);
    212 
    213 		(void)memset(&ysd->dom_server_addr, 0,
    214 			     sizeof ysd->dom_server_addr);
    215 		ysd->dom_server_addr.sin_len = sizeof(struct sockaddr_in);
    216 		ysd->dom_server_addr.sin_family = AF_INET;
    217 		bn = &ypbr.ypbind_respbody.ypbind_bindinfo;
    218 		ysd->dom_server_addr.sin_port =
    219 			bn->ypbind_binding_port;
    220 		ysd->dom_server_addr.sin_addr.s_addr =
    221 			bn->ypbind_binding_addr.s_addr;
    222 		ysd->dom_server_port =
    223 			bn->ypbind_binding_port;
    224 gotit:
    225 		ysd->dom_vers = YPVERS;
    226 		(void)strncpy(ysd->dom_domain, dom, sizeof(ysd->dom_domain)-1);
    227 	}
    228 	if (ysd->dom_client)
    229 		clnt_destroy(ysd->dom_client);
    230 	ysd->dom_socket = RPC_ANYSOCK;
    231 	ysd->dom_client = clntudp_create(&ysd->dom_server_addr,
    232 	    YPPROG, YPVERS, _yplib_rpc_timeout, &ysd->dom_socket);
    233 	if (ysd->dom_client == NULL) {
    234 		clnt_pcreateerror("clntudp_create");
    235 		ysd->dom_vers = -1;
    236 		goto again;
    237 	}
    238 	if (fcntl(ysd->dom_socket, F_SETFD, 1) == -1)
    239 		perror("fcntl: F_SETFD");
    240 
    241 	if (new) {
    242 		ysd->dom_pnext = _ypbindlist;
    243 		_ypbindlist = ysd;
    244 	}
    245 	if (ypdb != NULL)
    246 		*ypdb = ysd;
    247 	return 0;
    248 }
    249 
    250 void
    251 _yp_unbind(ypb)
    252 	struct dom_binding *ypb;
    253 {
    254 	clnt_destroy(ypb->dom_client);
    255 	ypb->dom_client = NULL;
    256 	ypb->dom_socket = -1;
    257 }
    258 
    259 int
    260 yp_bind(dom)
    261 	const char     *dom;
    262 {
    263 	if (_yp_invalid_domain(dom))
    264 		return YPERR_BADARGS;
    265 
    266 	return _yp_dobind(dom, NULL);
    267 }
    268 
    269 void
    270 yp_unbind(dom)
    271 	const char     *dom;
    272 {
    273 	struct dom_binding *ypb, *ypbp;
    274 
    275 	if (_yp_invalid_domain(dom))
    276 		return;
    277 
    278 	ypbp = NULL;
    279 	for (ypb = _ypbindlist; ypb; ypb = ypb->dom_pnext) {
    280 		if (strcmp(dom, ypb->dom_domain) == 0) {
    281 			clnt_destroy(ypb->dom_client);
    282 			if (ypbp)
    283 				ypbp->dom_pnext = ypb->dom_pnext;
    284 			else
    285 				_ypbindlist = ypb->dom_pnext;
    286 			free(ypb);
    287 			return;
    288 		}
    289 		ypbp = ypb;
    290 	}
    291 	return;
    292 }
    293 
    294 int
    295 yp_get_default_domain(domp)
    296 	char          **domp;
    297 {
    298 	*domp = NULL;
    299 	if (_yp_domain[0] == '\0')
    300 		if (getdomainname(_yp_domain, sizeof _yp_domain))
    301 			return YPERR_NODOM;
    302 	*domp = _yp_domain;
    303 	return 0;
    304 }
    305 
    306 int
    307 _yp_check(dom)
    308 	char          **dom;
    309 {
    310 	char           *unused;
    311 
    312 	if (_yp_domain[0] == '\0')
    313 		if (yp_get_default_domain(&unused))
    314 			return 0;
    315 
    316 	if (dom)
    317 		*dom = _yp_domain;
    318 
    319 	if (yp_bind(_yp_domain) == 0)
    320 		return 1;
    321 	return 0;
    322 }
    323 
    324 /*
    325  * _yp_invalid_domain: check if given domainname isn't RFC1035 compliant
    326  * returns non-zero if invalid
    327  */
    328 int
    329 _yp_invalid_domain(dom)
    330 	const char *dom;
    331 {
    332 	const char	*p;
    333 
    334 	if (dom == NULL || *dom == '\0')
    335 		return 1;
    336 
    337 #define	is_digit(x)	((x) >= '0' && (x) <= '9')
    338 #define	is_letter(x)	(((x) >= 'a' && (x) <= 'z') || ((x) >='A' && (x) <='Z'))
    339 
    340 	for (p = dom; *p != '\0'; p++) {
    341 		int len;
    342 		if (!is_letter(*p))		/* label starts with a letter */
    343 			return 1;
    344 		p++;
    345 		len = 0;			/* then has [-a-zA-Z0-9] */
    346 		while (is_digit(*p) || is_letter(*p) || *p == '-') {
    347 			p++;
    348 			if (++len > MAXLABEL)
    349 				return 1;	/* label is too long */
    350 		}
    351 		if (*(p-1) == '-')		/* no trailing - for label */
    352 			return 1;
    353 		if (*p == '\0')
    354 			break;
    355 		else if (*p != '.')
    356 			return 1;
    357 		else if (*(p+1) == '\0')	/* no trailing . for domain */
    358 			return 1;
    359 	}
    360 	if ((p - dom) > YPMAXDOMAIN)
    361 		return 1;
    362 	return 0;
    363 }
    364