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yplib.c revision 1.37 
      1 /*	$NetBSD: yplib.c,v 1.37 2000/07/06 03:14:05 christos 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 1.37 2000/07/06 03:14:05 christos 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, r;
     93 	int             nerrs = 0;
     94 
     95 	if (dom == NULL || *dom == '\0')
     96 		return YPERR_BADARGS;
     97 
     98 	/*
     99 	 * test if YP is running or not
    100 	 */
    101 	if ((fd = open(YPBINDLOCK, O_RDONLY)) == -1)
    102 		return YPERR_YPBIND;
    103 	if (!(flock(fd, LOCK_EX | LOCK_NB) == -1 && errno == EWOULDBLOCK)) {
    104 		(void)close(fd);
    105 		return YPERR_YPBIND;
    106 	}
    107 	(void)close(fd);
    108 
    109 	gpid = getpid();
    110 	if (!(pid == -1 || pid == gpid)) {
    111 		ysd = _ypbindlist;
    112 		while (ysd) {
    113 			if (ysd->dom_client)
    114 				clnt_destroy(ysd->dom_client);
    115 			ysd2 = ysd->dom_pnext;
    116 			free(ysd);
    117 			ysd = ysd2;
    118 		}
    119 		_ypbindlist = NULL;
    120 	}
    121 	pid = gpid;
    122 
    123 	if (ypdb != NULL)
    124 		*ypdb = NULL;
    125 
    126 	for (ysd = _ypbindlist; ysd; ysd = ysd->dom_pnext)
    127 		if (strcmp(dom, ysd->dom_domain) == 0)
    128 			break;
    129 	if (ysd == NULL) {
    130 		if ((ysd = malloc(sizeof *ysd)) == NULL)
    131 			return YPERR_YPERR;
    132 		(void)memset(ysd, 0, sizeof *ysd);
    133 		ysd->dom_socket = -1;
    134 		ysd->dom_vers = 0;
    135 		new = 1;
    136 	}
    137 again:
    138 	if (ysd->dom_vers == 0) {
    139 		(void) snprintf(path, sizeof(path), "%s/%s.%d",
    140 				BINDINGDIR, dom, 2);
    141 		if ((fd = open(path, O_RDONLY)) == -1) {
    142 			/*
    143 			 * no binding file, YP is dead, or not yet fully
    144 			 * alive.
    145 			 */
    146 			goto trynet;
    147 		}
    148 		if (flock(fd, LOCK_EX | LOCK_NB) == -1 &&
    149 		    errno == EWOULDBLOCK) {
    150 			struct iovec    iov[2];
    151 			struct ypbind_resp ybr;
    152 			u_short         ypb_port;
    153 			struct ypbind_binding *bn;
    154 
    155 			iov[0].iov_base = &ypb_port;
    156 			iov[0].iov_len = sizeof ypb_port;
    157 			iov[1].iov_base = &ybr;
    158 			iov[1].iov_len = sizeof ybr;
    159 
    160 			r = readv(fd, iov, 2);
    161 			if (r != iov[0].iov_len + iov[1].iov_len) {
    162 				(void)close(fd);
    163 				ysd->dom_vers = -1;
    164 				goto again;
    165 			}
    166 			(void)memset(&ysd->dom_server_addr, 0,
    167 				     sizeof ysd->dom_server_addr);
    168 			ysd->dom_server_addr.sin_len =
    169 				sizeof(struct sockaddr_in);
    170 			ysd->dom_server_addr.sin_family = AF_INET;
    171 			bn = &ybr.ypbind_respbody.ypbind_bindinfo;
    172 			ysd->dom_server_addr.sin_port =
    173 				bn->ypbind_binding_port;
    174 
    175 			ysd->dom_server_addr.sin_addr =
    176 				bn->ypbind_binding_addr;
    177 
    178 			ysd->dom_server_port = ysd->dom_server_addr.sin_port;
    179 			(void)close(fd);
    180 			goto gotit;
    181 		} else {
    182 			/* no lock on binding file, YP is dead. */
    183 			(void)close(fd);
    184 			if (new)
    185 				free(ysd);
    186 			return YPERR_YPBIND;
    187 		}
    188 	}
    189 trynet:
    190 	if (ysd->dom_vers == -1 || ysd->dom_vers == 0) {
    191 		struct ypbind_binding *bn;
    192 		(void)memset(&clnt_sin, 0, sizeof clnt_sin);
    193 		clnt_sin.sin_len = sizeof(struct sockaddr_in);
    194 		clnt_sin.sin_family = AF_INET;
    195 		clnt_sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
    196 
    197 		clnt_sock = RPC_ANYSOCK;
    198 		client = clnttcp_create(&clnt_sin, YPBINDPROG, YPBINDVERS,
    199 					&clnt_sock, 0, 0);
    200 		if (client == NULL) {
    201 			clnt_pcreateerror("clnttcp_create");
    202 			if (new)
    203 				free(ysd);
    204 			return YPERR_YPBIND;
    205 		}
    206 		r = clnt_call(client, (rpcproc_t)YPBINDPROC_DOMAIN,
    207 		    (xdrproc_t)xdr_ypdomain_wrap_string, &dom,
    208 		    (xdrproc_t)xdr_ypbind_resp, &ypbr, _yplib_timeout);
    209 		if (r != RPC_SUCCESS) {
    210 			if (new == 0 && ++nerrs == _yplib_nerrs) {
    211 				nerrs = 0;
    212 				fprintf(stderr,
    213 		    "YP server for domain %s not responding, still trying\n",
    214 				    dom);
    215 			}
    216 			clnt_destroy(client);
    217 			ysd->dom_vers = -1;
    218 			goto again;
    219 		}
    220 		clnt_destroy(client);
    221 
    222 		(void)memset(&ysd->dom_server_addr, 0,
    223 			     sizeof ysd->dom_server_addr);
    224 		ysd->dom_server_addr.sin_len = sizeof(struct sockaddr_in);
    225 		ysd->dom_server_addr.sin_family = AF_INET;
    226 		bn = &ypbr.ypbind_respbody.ypbind_bindinfo;
    227 		ysd->dom_server_addr.sin_port =
    228 			bn->ypbind_binding_port;
    229 		ysd->dom_server_addr.sin_addr.s_addr =
    230 			bn->ypbind_binding_addr.s_addr;
    231 		ysd->dom_server_port =
    232 			bn->ypbind_binding_port;
    233 gotit:
    234 		ysd->dom_vers = YPVERS;
    235 		(void)strncpy(ysd->dom_domain, dom, sizeof(ysd->dom_domain)-1);
    236 	}
    237 	if (ysd->dom_client)
    238 		clnt_destroy(ysd->dom_client);
    239 	ysd->dom_socket = RPC_ANYSOCK;
    240 	ysd->dom_client = clntudp_create(&ysd->dom_server_addr,
    241 	    YPPROG, YPVERS, _yplib_rpc_timeout, &ysd->dom_socket);
    242 	if (ysd->dom_client == NULL) {
    243 		clnt_pcreateerror("clntudp_create");
    244 		ysd->dom_vers = -1;
    245 		goto again;
    246 	}
    247 	if (fcntl(ysd->dom_socket, F_SETFD, 1) == -1)
    248 		perror("fcntl: F_SETFD");
    249 
    250 	if (new) {
    251 		ysd->dom_pnext = _ypbindlist;
    252 		_ypbindlist = ysd;
    253 	}
    254 	if (ypdb != NULL)
    255 		*ypdb = ysd;
    256 	return 0;
    257 }
    258 
    259 void
    260 __yp_unbind(ypb)
    261 	struct dom_binding *ypb;
    262 {
    263 
    264 	_DIAGASSERT(ypb != NULL);
    265 
    266 	clnt_destroy(ypb->dom_client);
    267 	ypb->dom_client = NULL;
    268 	ypb->dom_socket = -1;
    269 }
    270 
    271 int
    272 yp_bind(dom)
    273 	const char     *dom;
    274 {
    275 	if (_yp_invalid_domain(dom))
    276 		return YPERR_BADARGS;
    277 
    278 	return _yp_dobind(dom, NULL);
    279 }
    280 
    281 void
    282 yp_unbind(dom)
    283 	const char     *dom;
    284 {
    285 	struct dom_binding *ypb, *ypbp;
    286 
    287 	if (_yp_invalid_domain(dom))
    288 		return;
    289 
    290 	ypbp = NULL;
    291 	for (ypb = _ypbindlist; ypb; ypb = ypb->dom_pnext) {
    292 		if (strcmp(dom, ypb->dom_domain) == 0) {
    293 			clnt_destroy(ypb->dom_client);
    294 			if (ypbp)
    295 				ypbp->dom_pnext = ypb->dom_pnext;
    296 			else
    297 				_ypbindlist = ypb->dom_pnext;
    298 			free(ypb);
    299 			return;
    300 		}
    301 		ypbp = ypb;
    302 	}
    303 	return;
    304 }
    305 
    306 int
    307 yp_get_default_domain(domp)
    308 	char          **domp;
    309 {
    310 	if (domp == NULL)
    311 		return YPERR_BADARGS;
    312 	*domp = NULL;
    313 	if (_yp_domain[0] == '\0')
    314 		if (getdomainname(_yp_domain, sizeof _yp_domain))
    315 			return YPERR_NODOM;
    316 	*domp = _yp_domain;
    317 	return 0;
    318 }
    319 
    320 int
    321 _yp_check(dom)
    322 	char          **dom;
    323 {
    324 	char           *unused;
    325 
    326 	if (_yp_domain[0] == '\0')
    327 		if (yp_get_default_domain(&unused))
    328 			return 0;
    329 
    330 	if (dom)
    331 		*dom = _yp_domain;
    332 
    333 	if (yp_bind(_yp_domain) == 0)
    334 		return 1;
    335 	return 0;
    336 }
    337 
    338 /*
    339  * _yp_invalid_domain: check if given domainname isn't legal.
    340  * returns non-zero if invalid
    341  */
    342 int
    343 _yp_invalid_domain(dom)
    344 	const char *dom;
    345 {
    346 	if (dom == NULL || *dom == '\0')
    347 		return 1;
    348 
    349 	if (strlen(dom) > YPMAXDOMAIN)
    350 		return 1;
    351 
    352 	if (strchr(dom, '/') != NULL)
    353 		return 1;
    354 
    355 	return 0;
    356 }
    357