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yplib.c revision 1.43 
      1 /*	$NetBSD: yplib.c,v 1.43 2006/11/03 20:18:49 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 1.43 2006/11/03 20:18:49 christos Exp $");
     32 #endif
     33 
     34 #include "namespace.h"
     35 #include "reentrant.h"
     36 
     37 #include <sys/param.h>
     38 #include <sys/socket.h>
     39 #include <sys/file.h>
     40 #include <sys/uio.h>
     41 
     42 #include <arpa/nameser.h>
     43 
     44 #include <assert.h>
     45 #include <errno.h>
     46 #include <stdio.h>
     47 #include <stdlib.h>
     48 #include <string.h>
     49 #include <unistd.h>
     50 
     51 #include <rpc/rpc.h>
     52 #include <rpc/xdr.h>
     53 #include <rpcsvc/yp_prot.h>
     54 #include <rpcsvc/ypclnt.h>
     55 #include "local.h"
     56 
     57 #define BINDINGDIR	"/var/yp/binding"
     58 #define YPBINDLOCK	"/var/run/ypbind.lock"
     59 
     60 struct dom_binding *_ypbindlist;
     61 char _yp_domain[MAXHOSTNAMELEN];
     62 
     63 #define YPLIB_TIMEOUT		10
     64 #define YPLIB_RPC_RETRIES	4
     65 
     66 struct timeval _yplib_timeout = { YPLIB_TIMEOUT, 0 };
     67 struct timeval _yplib_rpc_timeout = { YPLIB_TIMEOUT / YPLIB_RPC_RETRIES,
     68 	1000000 * (YPLIB_TIMEOUT % YPLIB_RPC_RETRIES) / YPLIB_RPC_RETRIES };
     69 int _yplib_nerrs = 5;
     70 
     71 #ifdef __weak_alias
     72 __weak_alias(yp_bind, _yp_bind)
     73 __weak_alias(yp_unbind, _yp_unbind)
     74 __weak_alias(yp_get_default_domain, _yp_get_default_domain)
     75 #endif
     76 
     77 #ifdef _REENTRANT
     78 static 	mutex_t			_ypmutex = MUTEX_INITIALIZER;
     79 #define YPLOCK()		mutex_lock(&_ypmutex)
     80 #define YPUNLOCK()		mutex_unlock(&_ypmutex)
     81 #else
     82 #define YPLOCK()
     83 #define YPUNLOCK()
     84 #endif
     85 
     86 int
     87 _yp_dobind(dom, ypdb)
     88 	const char     *dom;
     89 	struct dom_binding **ypdb;
     90 {
     91 	static int      pid = -1;
     92 	char            path[MAXPATHLEN];
     93 	struct dom_binding *ysd, *ysd2;
     94 	struct ypbind_resp ypbr;
     95 	struct sockaddr_in clnt_sin;
     96 	int             clnt_sock, fd, gpid;
     97 	CLIENT         *client;
     98 	int             new = 0;
     99 	int             nerrs = 0;
    100 	ssize_t		r;
    101 
    102 	if (dom == NULL || *dom == '\0')
    103 		return YPERR_BADARGS;
    104 
    105 	/*
    106 	 * test if YP is running or not
    107 	 */
    108 	if ((fd = open(YPBINDLOCK, O_RDONLY)) == -1)
    109 		return YPERR_YPBIND;
    110 	if (!(flock(fd, LOCK_EX | LOCK_NB) == -1 && errno == EWOULDBLOCK)) {
    111 		(void)close(fd);
    112 		return YPERR_YPBIND;
    113 	}
    114 	(void)close(fd);
    115 
    116 	gpid = getpid();
    117 	if (!(pid == -1 || pid == gpid)) {
    118 		ysd = _ypbindlist;
    119 		while (ysd) {
    120 			if (ysd->dom_client)
    121 				clnt_destroy(ysd->dom_client);
    122 			ysd2 = ysd->dom_pnext;
    123 			free(ysd);
    124 			ysd = ysd2;
    125 		}
    126 		_ypbindlist = NULL;
    127 	}
    128 	pid = gpid;
    129 
    130 	if (ypdb != NULL)
    131 		*ypdb = NULL;
    132 
    133 	for (ysd = _ypbindlist; ysd; ysd = ysd->dom_pnext)
    134 		if (strcmp(dom, ysd->dom_domain) == 0)
    135 			break;
    136 	if (ysd == NULL) {
    137 		if ((ysd = malloc(sizeof *ysd)) == NULL)
    138 			return YPERR_YPERR;
    139 		(void)memset(ysd, 0, sizeof *ysd);
    140 		ysd->dom_socket = -1;
    141 		ysd->dom_vers = 0;
    142 		new = 1;
    143 	}
    144 again:
    145 	if (ysd->dom_vers == 0) {
    146 		(void) snprintf(path, sizeof(path), "%s/%s.%d",
    147 				BINDINGDIR, dom, 2);
    148 		if ((fd = open(path, O_RDONLY)) == -1) {
    149 			/*
    150 			 * no binding file, YP is dead, or not yet fully
    151 			 * alive.
    152 			 */
    153 			goto trynet;
    154 		}
    155 		if (flock(fd, LOCK_EX | LOCK_NB) == -1 &&
    156 		    errno == EWOULDBLOCK) {
    157 			struct iovec    iov[2];
    158 			struct ypbind_resp ybr;
    159 			u_short         ypb_port;
    160 			struct ypbind_binding *bn;
    161 
    162 			iov[0].iov_base = &ypb_port;
    163 			iov[0].iov_len = sizeof ypb_port;
    164 			iov[1].iov_base = &ybr;
    165 			iov[1].iov_len = sizeof ybr;
    166 
    167 			r = readv(fd, iov, 2);
    168 			if (r != (ssize_t)(iov[0].iov_len + iov[1].iov_len)) {
    169 				(void)close(fd);
    170 				ysd->dom_vers = -1;
    171 				goto again;
    172 			}
    173 			(void)memset(&ysd->dom_server_addr, 0,
    174 				     sizeof ysd->dom_server_addr);
    175 			ysd->dom_server_addr.sin_len =
    176 				sizeof(struct sockaddr_in);
    177 			ysd->dom_server_addr.sin_family = AF_INET;
    178 			bn = &ybr.ypbind_respbody.ypbind_bindinfo;
    179 			ysd->dom_server_addr.sin_port =
    180 				bn->ypbind_binding_port;
    181 
    182 			ysd->dom_server_addr.sin_addr =
    183 				bn->ypbind_binding_addr;
    184 
    185 			ysd->dom_server_port = ysd->dom_server_addr.sin_port;
    186 			(void)close(fd);
    187 			goto gotit;
    188 		} else {
    189 			/* no lock on binding file, YP is dead. */
    190 			(void)close(fd);
    191 			if (new)
    192 				free(ysd);
    193 			return YPERR_YPBIND;
    194 		}
    195 	}
    196 trynet:
    197 	if (ysd->dom_vers == -1 || ysd->dom_vers == 0) {
    198 		struct ypbind_binding *bn;
    199 		(void)memset(&clnt_sin, 0, sizeof clnt_sin);
    200 		clnt_sin.sin_len = sizeof(struct sockaddr_in);
    201 		clnt_sin.sin_family = AF_INET;
    202 		clnt_sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
    203 
    204 		clnt_sock = RPC_ANYSOCK;
    205 		client = clnttcp_create(&clnt_sin, YPBINDPROG, YPBINDVERS,
    206 					&clnt_sock, 0, 0);
    207 		if (client == NULL) {
    208 			clnt_pcreateerror("clnttcp_create");
    209 			if (new)
    210 				free(ysd);
    211 			return YPERR_YPBIND;
    212 		}
    213 		r = clnt_call(client, (rpcproc_t)YPBINDPROC_DOMAIN,
    214 		    (xdrproc_t)xdr_ypdomain_wrap_string, &dom,
    215 		    (xdrproc_t)xdr_ypbind_resp, &ypbr, _yplib_timeout);
    216 		if (r != RPC_SUCCESS) {
    217 			if (new == 0 && ++nerrs == _yplib_nerrs) {
    218 				nerrs = 0;
    219 				fprintf(stderr,
    220 		    "YP server for domain %s not responding, still trying\n",
    221 				    dom);
    222 			}
    223 			clnt_destroy(client);
    224 			ysd->dom_vers = -1;
    225 			goto again;
    226 		}
    227 		clnt_destroy(client);
    228 
    229 		(void)memset(&ysd->dom_server_addr, 0,
    230 			     sizeof ysd->dom_server_addr);
    231 		ysd->dom_server_addr.sin_len = sizeof(struct sockaddr_in);
    232 		ysd->dom_server_addr.sin_family = AF_INET;
    233 		bn = &ypbr.ypbind_respbody.ypbind_bindinfo;
    234 		ysd->dom_server_addr.sin_port =
    235 			bn->ypbind_binding_port;
    236 		ysd->dom_server_addr.sin_addr.s_addr =
    237 			bn->ypbind_binding_addr.s_addr;
    238 		ysd->dom_server_port =
    239 			bn->ypbind_binding_port;
    240 gotit:
    241 		ysd->dom_vers = YPVERS;
    242 		(void)strlcpy(ysd->dom_domain, dom, sizeof(ysd->dom_domain));
    243 	}
    244 	if (ysd->dom_client)
    245 		clnt_destroy(ysd->dom_client);
    246 	ysd->dom_socket = RPC_ANYSOCK;
    247 	ysd->dom_client = clntudp_create(&ysd->dom_server_addr,
    248 	    YPPROG, YPVERS, _yplib_rpc_timeout, &ysd->dom_socket);
    249 	if (ysd->dom_client == NULL) {
    250 		clnt_pcreateerror("clntudp_create");
    251 		ysd->dom_vers = -1;
    252 		goto again;
    253 	}
    254 	if (fcntl(ysd->dom_socket, F_SETFD, FD_CLOEXEC) == -1)
    255 		perror("fcntl: F_SETFD");
    256 
    257 	if (new) {
    258 		ysd->dom_pnext = _ypbindlist;
    259 		_ypbindlist = ysd;
    260 	}
    261 	if (ypdb != NULL)
    262 		*ypdb = ysd;
    263 	return 0;
    264 }
    265 
    266 void
    267 __yp_unbind(ypb)
    268 	struct dom_binding *ypb;
    269 {
    270 
    271 	_DIAGASSERT(ypb != NULL);
    272 
    273 	clnt_destroy(ypb->dom_client);
    274 	ypb->dom_client = NULL;
    275 	ypb->dom_socket = -1;
    276 }
    277 
    278 int
    279 yp_bind(dom)
    280 	const char     *dom;
    281 {
    282 	if (_yp_invalid_domain(dom))
    283 		return YPERR_BADARGS;
    284 
    285 	return _yp_dobind(dom, NULL);
    286 }
    287 
    288 void
    289 yp_unbind(dom)
    290 	const char     *dom;
    291 {
    292 	struct dom_binding *ypb, *ypbp;
    293 
    294 	if (_yp_invalid_domain(dom))
    295 		return;
    296 
    297 	ypbp = NULL;
    298 	for (ypb = _ypbindlist; ypb; ypb = ypb->dom_pnext) {
    299 		if (strcmp(dom, ypb->dom_domain) == 0) {
    300 			clnt_destroy(ypb->dom_client);
    301 			if (ypbp)
    302 				ypbp->dom_pnext = ypb->dom_pnext;
    303 			else
    304 				_ypbindlist = ypb->dom_pnext;
    305 			free(ypb);
    306 			return;
    307 		}
    308 		ypbp = ypb;
    309 	}
    310 	return;
    311 }
    312 
    313 int
    314 yp_get_default_domain(domp)
    315 	char          **domp;
    316 {
    317 	if (domp == NULL)
    318 		return YPERR_BADARGS;
    319 	*domp = NULL;
    320 	if (_yp_domain[0] == '\0')
    321 		if (getdomainname(_yp_domain, sizeof _yp_domain))
    322 			return YPERR_NODOM;
    323 	*domp = _yp_domain;
    324 	return 0;
    325 }
    326 
    327 int
    328 _yp_check(dom)
    329 	char          **dom;
    330 {
    331 	char           *unused;
    332 	int 		good;
    333 
    334 	YPLOCK();
    335 
    336 	if (_yp_domain[0] == '\0')
    337 		if (yp_get_default_domain(&unused)) {
    338 			good = 0;
    339 			goto done;
    340 		}
    341 	if (dom)
    342 		*dom = _yp_domain;
    343 
    344 	good = yp_bind(_yp_domain) == 0;
    345 done:
    346 	YPUNLOCK();
    347 	return good;
    348 }
    349 
    350 /*
    351  * _yp_invalid_domain: check if given domainname isn't legal.
    352  * returns non-zero if invalid
    353  */
    354 int
    355 _yp_invalid_domain(dom)
    356 	const char *dom;
    357 {
    358 	if (dom == NULL || *dom == '\0')
    359 		return 1;
    360 
    361 	if (strlen(dom) > YPMAXDOMAIN)
    362 		return 1;
    363 
    364 	if (strchr(dom, '/') != NULL)
    365 		return 1;
    366 
    367 	return 0;
    368 }
    369