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yplib.c revision 1.41 
      1 /*	$NetBSD: yplib.c,v 1.41 2004/05/27 18:41:11 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  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     17  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     18  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
     20  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 #if defined(LIBC_SCCS) && !defined(lint)
     31 __RCSID("$NetBSD: yplib.c,v 1.41 2004/05/27 18:41:11 christos Exp $");
     32 #endif
     33 
     34 #include "namespace.h"
     35 #include <sys/param.h>
     36 #include <sys/socket.h>
     37 #include <sys/file.h>
     38 #include <sys/uio.h>
     39 
     40 #include <arpa/nameser.h>
     41 
     42 #include <assert.h>
     43 #include <errno.h>
     44 #include <stdio.h>
     45 #include <stdlib.h>
     46 #include <string.h>
     47 #include <unistd.h>
     48 
     49 #include <rpc/rpc.h>
     50 #include <rpc/xdr.h>
     51 #include <rpcsvc/yp_prot.h>
     52 #include <rpcsvc/ypclnt.h>
     53 #include <threadlib.h>
     54 #include "local.h"
     55 
     56 #define BINDINGDIR	"/var/yp/binding"
     57 #define YPBINDLOCK	"/var/run/ypbind.lock"
     58 
     59 struct dom_binding *_ypbindlist;
     60 char _yp_domain[MAXHOSTNAMELEN];
     61 
     62 #define YPLIB_TIMEOUT		10
     63 #define YPLIB_RPC_RETRIES	4
     64 
     65 struct timeval _yplib_timeout = { YPLIB_TIMEOUT, 0 };
     66 struct timeval _yplib_rpc_timeout = { YPLIB_TIMEOUT / YPLIB_RPC_RETRIES,
     67 	1000000 * (YPLIB_TIMEOUT % YPLIB_RPC_RETRIES) / YPLIB_RPC_RETRIES };
     68 int _yplib_nerrs = 5;
     69 
     70 #ifdef __weak_alias
     71 __weak_alias(yp_bind, _yp_bind)
     72 __weak_alias(yp_unbind, _yp_unbind)
     73 __weak_alias(yp_get_default_domain, _yp_get_default_domain)
     74 #endif
     75 
     76 #ifdef _REENTRANT
     77 static 	mutex_t			_ypmutex = MUTEX_INITIALIZER;
     78 #define YPLOCK()		mutex_lock(&_ypmutex)
     79 #define YPUNLOCK()		mutex_unlock(&_ypmutex)
     80 #else
     81 #define YPLOCK()
     82 #define YPUNLOCK()
     83 #endif
     84 
     85 int
     86 _yp_dobind(dom, ypdb)
     87 	const char     *dom;
     88 	struct dom_binding **ypdb;
     89 {
     90 	static int      pid = -1;
     91 	char            path[MAXPATHLEN];
     92 	struct dom_binding *ysd, *ysd2;
     93 	struct ypbind_resp ypbr;
     94 	struct sockaddr_in clnt_sin;
     95 	int             clnt_sock, fd, gpid;
     96 	CLIENT         *client;
     97 	int             new = 0;
     98 	int             nerrs = 0;
     99 	ssize_t		r;
    100 
    101 	if (dom == NULL || *dom == '\0')
    102 		return YPERR_BADARGS;
    103 
    104 	/*
    105 	 * test if YP is running or not
    106 	 */
    107 	if ((fd = open(YPBINDLOCK, O_RDONLY)) == -1)
    108 		return YPERR_YPBIND;
    109 	if (!(flock(fd, LOCK_EX | LOCK_NB) == -1 && errno == EWOULDBLOCK)) {
    110 		(void)close(fd);
    111 		return YPERR_YPBIND;
    112 	}
    113 	(void)close(fd);
    114 
    115 	gpid = getpid();
    116 	if (!(pid == -1 || pid == gpid)) {
    117 		ysd = _ypbindlist;
    118 		while (ysd) {
    119 			if (ysd->dom_client)
    120 				clnt_destroy(ysd->dom_client);
    121 			ysd2 = ysd->dom_pnext;
    122 			free(ysd);
    123 			ysd = ysd2;
    124 		}
    125 		_ypbindlist = NULL;
    126 	}
    127 	pid = gpid;
    128 
    129 	if (ypdb != NULL)
    130 		*ypdb = NULL;
    131 
    132 	for (ysd = _ypbindlist; ysd; ysd = ysd->dom_pnext)
    133 		if (strcmp(dom, ysd->dom_domain) == 0)
    134 			break;
    135 	if (ysd == NULL) {
    136 		if ((ysd = malloc(sizeof *ysd)) == NULL)
    137 			return YPERR_YPERR;
    138 		(void)memset(ysd, 0, sizeof *ysd);
    139 		ysd->dom_socket = -1;
    140 		ysd->dom_vers = 0;
    141 		new = 1;
    142 	}
    143 again:
    144 	if (ysd->dom_vers == 0) {
    145 		(void) snprintf(path, sizeof(path), "%s/%s.%d",
    146 				BINDINGDIR, dom, 2);
    147 		if ((fd = open(path, O_RDONLY)) == -1) {
    148 			/*
    149 			 * no binding file, YP is dead, or not yet fully
    150 			 * alive.
    151 			 */
    152 			goto trynet;
    153 		}
    154 		if (flock(fd, LOCK_EX | LOCK_NB) == -1 &&
    155 		    errno == EWOULDBLOCK) {
    156 			struct iovec    iov[2];
    157 			struct ypbind_resp ybr;
    158 			u_short         ypb_port;
    159 			struct ypbind_binding *bn;
    160 
    161 			iov[0].iov_base = &ypb_port;
    162 			iov[0].iov_len = sizeof ypb_port;
    163 			iov[1].iov_base = &ybr;
    164 			iov[1].iov_len = sizeof ybr;
    165 
    166 			r = readv(fd, iov, 2);
    167 			if (r != (ssize_t)(iov[0].iov_len + iov[1].iov_len)) {
    168 				(void)close(fd);
    169 				ysd->dom_vers = -1;
    170 				goto again;
    171 			}
    172 			(void)memset(&ysd->dom_server_addr, 0,
    173 				     sizeof ysd->dom_server_addr);
    174 			ysd->dom_server_addr.sin_len =
    175 				sizeof(struct sockaddr_in);
    176 			ysd->dom_server_addr.sin_family = AF_INET;
    177 			bn = &ybr.ypbind_respbody.ypbind_bindinfo;
    178 			ysd->dom_server_addr.sin_port =
    179 				bn->ypbind_binding_port;
    180 
    181 			ysd->dom_server_addr.sin_addr =
    182 				bn->ypbind_binding_addr;
    183 
    184 			ysd->dom_server_port = ysd->dom_server_addr.sin_port;
    185 			(void)close(fd);
    186 			goto gotit;
    187 		} else {
    188 			/* no lock on binding file, YP is dead. */
    189 			(void)close(fd);
    190 			if (new)
    191 				free(ysd);
    192 			return YPERR_YPBIND;
    193 		}
    194 	}
    195 trynet:
    196 	if (ysd->dom_vers == -1 || ysd->dom_vers == 0) {
    197 		struct ypbind_binding *bn;
    198 		(void)memset(&clnt_sin, 0, sizeof clnt_sin);
    199 		clnt_sin.sin_len = sizeof(struct sockaddr_in);
    200 		clnt_sin.sin_family = AF_INET;
    201 		clnt_sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
    202 
    203 		clnt_sock = RPC_ANYSOCK;
    204 		client = clnttcp_create(&clnt_sin, YPBINDPROG, YPBINDVERS,
    205 					&clnt_sock, 0, 0);
    206 		if (client == NULL) {
    207 			clnt_pcreateerror("clnttcp_create");
    208 			if (new)
    209 				free(ysd);
    210 			return YPERR_YPBIND;
    211 		}
    212 		r = clnt_call(client, (rpcproc_t)YPBINDPROC_DOMAIN,
    213 		    (xdrproc_t)xdr_ypdomain_wrap_string, &dom,
    214 		    (xdrproc_t)xdr_ypbind_resp, &ypbr, _yplib_timeout);
    215 		if (r != RPC_SUCCESS) {
    216 			if (new == 0 && ++nerrs == _yplib_nerrs) {
    217 				nerrs = 0;
    218 				fprintf(stderr,
    219 		    "YP server for domain %s not responding, still trying\n",
    220 				    dom);
    221 			}
    222 			clnt_destroy(client);
    223 			ysd->dom_vers = -1;
    224 			goto again;
    225 		}
    226 		clnt_destroy(client);
    227 
    228 		(void)memset(&ysd->dom_server_addr, 0,
    229 			     sizeof ysd->dom_server_addr);
    230 		ysd->dom_server_addr.sin_len = sizeof(struct sockaddr_in);
    231 		ysd->dom_server_addr.sin_family = AF_INET;
    232 		bn = &ypbr.ypbind_respbody.ypbind_bindinfo;
    233 		ysd->dom_server_addr.sin_port =
    234 			bn->ypbind_binding_port;
    235 		ysd->dom_server_addr.sin_addr.s_addr =
    236 			bn->ypbind_binding_addr.s_addr;
    237 		ysd->dom_server_port =
    238 			bn->ypbind_binding_port;
    239 gotit:
    240 		ysd->dom_vers = YPVERS;
    241 		(void)strlcpy(ysd->dom_domain, dom, sizeof(ysd->dom_domain));
    242 	}
    243 	if (ysd->dom_client)
    244 		clnt_destroy(ysd->dom_client);
    245 	ysd->dom_socket = RPC_ANYSOCK;
    246 	ysd->dom_client = clntudp_create(&ysd->dom_server_addr,
    247 	    YPPROG, YPVERS, _yplib_rpc_timeout, &ysd->dom_socket);
    248 	if (ysd->dom_client == NULL) {
    249 		clnt_pcreateerror("clntudp_create");
    250 		ysd->dom_vers = -1;
    251 		goto again;
    252 	}
    253 	if (fcntl(ysd->dom_socket, F_SETFD, 1) == -1)
    254 		perror("fcntl: F_SETFD");
    255 
    256 	if (new) {
    257 		ysd->dom_pnext = _ypbindlist;
    258 		_ypbindlist = ysd;
    259 	}
    260 	if (ypdb != NULL)
    261 		*ypdb = ysd;
    262 	return 0;
    263 }
    264 
    265 void
    266 __yp_unbind(ypb)
    267 	struct dom_binding *ypb;
    268 {
    269 
    270 	_DIAGASSERT(ypb != NULL);
    271 
    272 	clnt_destroy(ypb->dom_client);
    273 	ypb->dom_client = NULL;
    274 	ypb->dom_socket = -1;
    275 }
    276 
    277 int
    278 yp_bind(dom)
    279 	const char     *dom;
    280 {
    281 	if (_yp_invalid_domain(dom))
    282 		return YPERR_BADARGS;
    283 
    284 	return _yp_dobind(dom, NULL);
    285 }
    286 
    287 void
    288 yp_unbind(dom)
    289 	const char     *dom;
    290 {
    291 	struct dom_binding *ypb, *ypbp;
    292 
    293 	if (_yp_invalid_domain(dom))
    294 		return;
    295 
    296 	ypbp = NULL;
    297 	for (ypb = _ypbindlist; ypb; ypb = ypb->dom_pnext) {
    298 		if (strcmp(dom, ypb->dom_domain) == 0) {
    299 			clnt_destroy(ypb->dom_client);
    300 			if (ypbp)
    301 				ypbp->dom_pnext = ypb->dom_pnext;
    302 			else
    303 				_ypbindlist = ypb->dom_pnext;
    304 			free(ypb);
    305 			return;
    306 		}
    307 		ypbp = ypb;
    308 	}
    309 	return;
    310 }
    311 
    312 int
    313 yp_get_default_domain(domp)
    314 	char          **domp;
    315 {
    316 	if (domp == NULL)
    317 		return YPERR_BADARGS;
    318 	*domp = NULL;
    319 	if (_yp_domain[0] == '\0')
    320 		if (getdomainname(_yp_domain, sizeof _yp_domain))
    321 			return YPERR_NODOM;
    322 	*domp = _yp_domain;
    323 	return 0;
    324 }
    325 
    326 int
    327 _yp_check(dom)
    328 	char          **dom;
    329 {
    330 	char           *unused;
    331 	int 		good;
    332 
    333 	YPLOCK();
    334 
    335 	if (_yp_domain[0] == '\0')
    336 		if (yp_get_default_domain(&unused)) {
    337 			good = 0;
    338 			goto done;
    339 		}
    340 	if (dom)
    341 		*dom = _yp_domain;
    342 
    343 	good = yp_bind(_yp_domain) == 0;
    344 done:
    345 	YPUNLOCK();
    346 	return good;
    347 }
    348 
    349 /*
    350  * _yp_invalid_domain: check if given domainname isn't legal.
    351  * returns non-zero if invalid
    352  */
    353 int
    354 _yp_invalid_domain(dom)
    355 	const char *dom;
    356 {
    357 	if (dom == NULL || *dom == '\0')
    358 		return 1;
    359 
    360 	if (strlen(dom) > YPMAXDOMAIN)
    361 		return 1;
    362 
    363 	if (strchr(dom, '/') != NULL)
    364 		return 1;
    365 
    366 	return 0;
    367 }
    368