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yplib.c revision 1.38 
      1 /*	$NetBSD: yplib.c,v 1.38 2002/11/11 22:53:19 thorpej 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 #include <sys/cdefs.h>
     35 #if defined(LIBC_SCCS) && !defined(lint)
     36 __RCSID("$NetBSD: yplib.c,v 1.38 2002/11/11 22:53:19 thorpej Exp $");
     37 #endif
     38 
     39 #include "namespace.h"
     40 #include <sys/param.h>
     41 #include <sys/socket.h>
     42 #include <sys/file.h>
     43 #include <sys/uio.h>
     44 
     45 #include <arpa/nameser.h>
     46 
     47 #include <assert.h>
     48 #include <errno.h>
     49 #include <stdio.h>
     50 #include <stdlib.h>
     51 #include <string.h>
     52 #include <unistd.h>
     53 
     54 #include <rpc/rpc.h>
     55 #include <rpc/xdr.h>
     56 #include <rpcsvc/yp_prot.h>
     57 #include <rpcsvc/ypclnt.h>
     58 #include "local.h"
     59 
     60 #define BINDINGDIR	"/var/yp/binding"
     61 #define YPBINDLOCK	"/var/run/ypbind.lock"
     62 
     63 struct dom_binding *_ypbindlist;
     64 char _yp_domain[MAXHOSTNAMELEN];
     65 
     66 #define YPLIB_TIMEOUT		10
     67 #define YPLIB_RPC_RETRIES	4
     68 
     69 struct timeval _yplib_timeout = { YPLIB_TIMEOUT, 0 };
     70 struct timeval _yplib_rpc_timeout = { YPLIB_TIMEOUT / YPLIB_RPC_RETRIES,
     71 	1000000 * (YPLIB_TIMEOUT % YPLIB_RPC_RETRIES) / YPLIB_RPC_RETRIES };
     72 int _yplib_nerrs = 5;
     73 
     74 #ifdef __weak_alias
     75 __weak_alias(yp_bind, _yp_bind)
     76 __weak_alias(yp_unbind, _yp_unbind)
     77 __weak_alias(yp_get_default_domain, _yp_get_default_domain)
     78 #endif
     79 
     80 int
     81 _yp_dobind(dom, ypdb)
     82 	const char     *dom;
     83 	struct dom_binding **ypdb;
     84 {
     85 	static int      pid = -1;
     86 	char            path[MAXPATHLEN];
     87 	struct dom_binding *ysd, *ysd2;
     88 	struct ypbind_resp ypbr;
     89 	struct sockaddr_in clnt_sin;
     90 	int             clnt_sock, fd, gpid;
     91 	CLIENT         *client;
     92 	int             new = 0;
     93 	int             nerrs = 0;
     94 	ssize_t		r;
     95 
     96 	if (dom == NULL || *dom == '\0')
     97 		return YPERR_BADARGS;
     98 
     99 	/*
    100 	 * test if YP is running or not
    101 	 */
    102 	if ((fd = open(YPBINDLOCK, O_RDONLY)) == -1)
    103 		return YPERR_YPBIND;
    104 	if (!(flock(fd, LOCK_EX | LOCK_NB) == -1 && errno == EWOULDBLOCK)) {
    105 		(void)close(fd);
    106 		return YPERR_YPBIND;
    107 	}
    108 	(void)close(fd);
    109 
    110 	gpid = getpid();
    111 	if (!(pid == -1 || pid == gpid)) {
    112 		ysd = _ypbindlist;
    113 		while (ysd) {
    114 			if (ysd->dom_client)
    115 				clnt_destroy(ysd->dom_client);
    116 			ysd2 = ysd->dom_pnext;
    117 			free(ysd);
    118 			ysd = ysd2;
    119 		}
    120 		_ypbindlist = NULL;
    121 	}
    122 	pid = gpid;
    123 
    124 	if (ypdb != NULL)
    125 		*ypdb = NULL;
    126 
    127 	for (ysd = _ypbindlist; ysd; ysd = ysd->dom_pnext)
    128 		if (strcmp(dom, ysd->dom_domain) == 0)
    129 			break;
    130 	if (ysd == NULL) {
    131 		if ((ysd = malloc(sizeof *ysd)) == NULL)
    132 			return YPERR_YPERR;
    133 		(void)memset(ysd, 0, sizeof *ysd);
    134 		ysd->dom_socket = -1;
    135 		ysd->dom_vers = 0;
    136 		new = 1;
    137 	}
    138 again:
    139 	if (ysd->dom_vers == 0) {
    140 		(void) snprintf(path, sizeof(path), "%s/%s.%d",
    141 				BINDINGDIR, dom, 2);
    142 		if ((fd = open(path, O_RDONLY)) == -1) {
    143 			/*
    144 			 * no binding file, YP is dead, or not yet fully
    145 			 * alive.
    146 			 */
    147 			goto trynet;
    148 		}
    149 		if (flock(fd, LOCK_EX | LOCK_NB) == -1 &&
    150 		    errno == EWOULDBLOCK) {
    151 			struct iovec    iov[2];
    152 			struct ypbind_resp ybr;
    153 			u_short         ypb_port;
    154 			struct ypbind_binding *bn;
    155 
    156 			iov[0].iov_base = &ypb_port;
    157 			iov[0].iov_len = sizeof ypb_port;
    158 			iov[1].iov_base = &ybr;
    159 			iov[1].iov_len = sizeof ybr;
    160 
    161 			r = readv(fd, iov, 2);
    162 			if (r != (ssize_t)(iov[0].iov_len + iov[1].iov_len)) {
    163 				(void)close(fd);
    164 				ysd->dom_vers = -1;
    165 				goto again;
    166 			}
    167 			(void)memset(&ysd->dom_server_addr, 0,
    168 				     sizeof ysd->dom_server_addr);
    169 			ysd->dom_server_addr.sin_len =
    170 				sizeof(struct sockaddr_in);
    171 			ysd->dom_server_addr.sin_family = AF_INET;
    172 			bn = &ybr.ypbind_respbody.ypbind_bindinfo;
    173 			ysd->dom_server_addr.sin_port =
    174 				bn->ypbind_binding_port;
    175 
    176 			ysd->dom_server_addr.sin_addr =
    177 				bn->ypbind_binding_addr;
    178 
    179 			ysd->dom_server_port = ysd->dom_server_addr.sin_port;
    180 			(void)close(fd);
    181 			goto gotit;
    182 		} else {
    183 			/* no lock on binding file, YP is dead. */
    184 			(void)close(fd);
    185 			if (new)
    186 				free(ysd);
    187 			return YPERR_YPBIND;
    188 		}
    189 	}
    190 trynet:
    191 	if (ysd->dom_vers == -1 || ysd->dom_vers == 0) {
    192 		struct ypbind_binding *bn;
    193 		(void)memset(&clnt_sin, 0, sizeof clnt_sin);
    194 		clnt_sin.sin_len = sizeof(struct sockaddr_in);
    195 		clnt_sin.sin_family = AF_INET;
    196 		clnt_sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
    197 
    198 		clnt_sock = RPC_ANYSOCK;
    199 		client = clnttcp_create(&clnt_sin, YPBINDPROG, YPBINDVERS,
    200 					&clnt_sock, 0, 0);
    201 		if (client == NULL) {
    202 			clnt_pcreateerror("clnttcp_create");
    203 			if (new)
    204 				free(ysd);
    205 			return YPERR_YPBIND;
    206 		}
    207 		r = clnt_call(client, (rpcproc_t)YPBINDPROC_DOMAIN,
    208 		    (xdrproc_t)xdr_ypdomain_wrap_string, &dom,
    209 		    (xdrproc_t)xdr_ypbind_resp, &ypbr, _yplib_timeout);
    210 		if (r != RPC_SUCCESS) {
    211 			if (new == 0 && ++nerrs == _yplib_nerrs) {
    212 				nerrs = 0;
    213 				fprintf(stderr,
    214 		    "YP server for domain %s not responding, still trying\n",
    215 				    dom);
    216 			}
    217 			clnt_destroy(client);
    218 			ysd->dom_vers = -1;
    219 			goto again;
    220 		}
    221 		clnt_destroy(client);
    222 
    223 		(void)memset(&ysd->dom_server_addr, 0,
    224 			     sizeof ysd->dom_server_addr);
    225 		ysd->dom_server_addr.sin_len = sizeof(struct sockaddr_in);
    226 		ysd->dom_server_addr.sin_family = AF_INET;
    227 		bn = &ypbr.ypbind_respbody.ypbind_bindinfo;
    228 		ysd->dom_server_addr.sin_port =
    229 			bn->ypbind_binding_port;
    230 		ysd->dom_server_addr.sin_addr.s_addr =
    231 			bn->ypbind_binding_addr.s_addr;
    232 		ysd->dom_server_port =
    233 			bn->ypbind_binding_port;
    234 gotit:
    235 		ysd->dom_vers = YPVERS;
    236 		(void)strncpy(ysd->dom_domain, dom, sizeof(ysd->dom_domain)-1);
    237 	}
    238 	if (ysd->dom_client)
    239 		clnt_destroy(ysd->dom_client);
    240 	ysd->dom_socket = RPC_ANYSOCK;
    241 	ysd->dom_client = clntudp_create(&ysd->dom_server_addr,
    242 	    YPPROG, YPVERS, _yplib_rpc_timeout, &ysd->dom_socket);
    243 	if (ysd->dom_client == NULL) {
    244 		clnt_pcreateerror("clntudp_create");
    245 		ysd->dom_vers = -1;
    246 		goto again;
    247 	}
    248 	if (fcntl(ysd->dom_socket, F_SETFD, 1) == -1)
    249 		perror("fcntl: F_SETFD");
    250 
    251 	if (new) {
    252 		ysd->dom_pnext = _ypbindlist;
    253 		_ypbindlist = ysd;
    254 	}
    255 	if (ypdb != NULL)
    256 		*ypdb = ysd;
    257 	return 0;
    258 }
    259 
    260 void
    261 __yp_unbind(ypb)
    262 	struct dom_binding *ypb;
    263 {
    264 
    265 	_DIAGASSERT(ypb != NULL);
    266 
    267 	clnt_destroy(ypb->dom_client);
    268 	ypb->dom_client = NULL;
    269 	ypb->dom_socket = -1;
    270 }
    271 
    272 int
    273 yp_bind(dom)
    274 	const char     *dom;
    275 {
    276 	if (_yp_invalid_domain(dom))
    277 		return YPERR_BADARGS;
    278 
    279 	return _yp_dobind(dom, NULL);
    280 }
    281 
    282 void
    283 yp_unbind(dom)
    284 	const char     *dom;
    285 {
    286 	struct dom_binding *ypb, *ypbp;
    287 
    288 	if (_yp_invalid_domain(dom))
    289 		return;
    290 
    291 	ypbp = NULL;
    292 	for (ypb = _ypbindlist; ypb; ypb = ypb->dom_pnext) {
    293 		if (strcmp(dom, ypb->dom_domain) == 0) {
    294 			clnt_destroy(ypb->dom_client);
    295 			if (ypbp)
    296 				ypbp->dom_pnext = ypb->dom_pnext;
    297 			else
    298 				_ypbindlist = ypb->dom_pnext;
    299 			free(ypb);
    300 			return;
    301 		}
    302 		ypbp = ypb;
    303 	}
    304 	return;
    305 }
    306 
    307 int
    308 yp_get_default_domain(domp)
    309 	char          **domp;
    310 {
    311 	if (domp == NULL)
    312 		return YPERR_BADARGS;
    313 	*domp = NULL;
    314 	if (_yp_domain[0] == '\0')
    315 		if (getdomainname(_yp_domain, sizeof _yp_domain))
    316 			return YPERR_NODOM;
    317 	*domp = _yp_domain;
    318 	return 0;
    319 }
    320 
    321 int
    322 _yp_check(dom)
    323 	char          **dom;
    324 {
    325 	char           *unused;
    326 
    327 	if (_yp_domain[0] == '\0')
    328 		if (yp_get_default_domain(&unused))
    329 			return 0;
    330 
    331 	if (dom)
    332 		*dom = _yp_domain;
    333 
    334 	if (yp_bind(_yp_domain) == 0)
    335 		return 1;
    336 	return 0;
    337 }
    338 
    339 /*
    340  * _yp_invalid_domain: check if given domainname isn't legal.
    341  * returns non-zero if invalid
    342  */
    343 int
    344 _yp_invalid_domain(dom)
    345 	const char *dom;
    346 {
    347 	if (dom == NULL || *dom == '\0')
    348 		return 1;
    349 
    350 	if (strlen(dom) > YPMAXDOMAIN)
    351 		return 1;
    352 
    353 	if (strchr(dom, '/') != NULL)
    354 		return 1;
    355 
    356 	return 0;
    357 }
    358