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yplib.c revision 1.40 
      1 /*	$NetBSD: yplib.c,v 1.40 2003/12/10 12:06:25 agc 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 1.40 2003/12/10 12:06:25 agc 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 "local.h"
     54 
     55 #define BINDINGDIR	"/var/yp/binding"
     56 #define YPBINDLOCK	"/var/run/ypbind.lock"
     57 
     58 struct dom_binding *_ypbindlist;
     59 char _yp_domain[MAXHOSTNAMELEN];
     60 
     61 #define YPLIB_TIMEOUT		10
     62 #define YPLIB_RPC_RETRIES	4
     63 
     64 struct timeval _yplib_timeout = { YPLIB_TIMEOUT, 0 };
     65 struct timeval _yplib_rpc_timeout = { YPLIB_TIMEOUT / YPLIB_RPC_RETRIES,
     66 	1000000 * (YPLIB_TIMEOUT % YPLIB_RPC_RETRIES) / YPLIB_RPC_RETRIES };
     67 int _yplib_nerrs = 5;
     68 
     69 #ifdef __weak_alias
     70 __weak_alias(yp_bind, _yp_bind)
     71 __weak_alias(yp_unbind, _yp_unbind)
     72 __weak_alias(yp_get_default_domain, _yp_get_default_domain)
     73 #endif
     74 
     75 int
     76 _yp_dobind(dom, ypdb)
     77 	const char     *dom;
     78 	struct dom_binding **ypdb;
     79 {
     80 	static int      pid = -1;
     81 	char            path[MAXPATHLEN];
     82 	struct dom_binding *ysd, *ysd2;
     83 	struct ypbind_resp ypbr;
     84 	struct sockaddr_in clnt_sin;
     85 	int             clnt_sock, fd, gpid;
     86 	CLIENT         *client;
     87 	int             new = 0;
     88 	int             nerrs = 0;
     89 	ssize_t		r;
     90 
     91 	if (dom == NULL || *dom == '\0')
     92 		return YPERR_BADARGS;
     93 
     94 	/*
     95 	 * test if YP is running or not
     96 	 */
     97 	if ((fd = open(YPBINDLOCK, O_RDONLY)) == -1)
     98 		return YPERR_YPBIND;
     99 	if (!(flock(fd, LOCK_EX | LOCK_NB) == -1 && errno == EWOULDBLOCK)) {
    100 		(void)close(fd);
    101 		return YPERR_YPBIND;
    102 	}
    103 	(void)close(fd);
    104 
    105 	gpid = getpid();
    106 	if (!(pid == -1 || pid == gpid)) {
    107 		ysd = _ypbindlist;
    108 		while (ysd) {
    109 			if (ysd->dom_client)
    110 				clnt_destroy(ysd->dom_client);
    111 			ysd2 = ysd->dom_pnext;
    112 			free(ysd);
    113 			ysd = ysd2;
    114 		}
    115 		_ypbindlist = NULL;
    116 	}
    117 	pid = gpid;
    118 
    119 	if (ypdb != NULL)
    120 		*ypdb = NULL;
    121 
    122 	for (ysd = _ypbindlist; ysd; ysd = ysd->dom_pnext)
    123 		if (strcmp(dom, ysd->dom_domain) == 0)
    124 			break;
    125 	if (ysd == NULL) {
    126 		if ((ysd = malloc(sizeof *ysd)) == NULL)
    127 			return YPERR_YPERR;
    128 		(void)memset(ysd, 0, sizeof *ysd);
    129 		ysd->dom_socket = -1;
    130 		ysd->dom_vers = 0;
    131 		new = 1;
    132 	}
    133 again:
    134 	if (ysd->dom_vers == 0) {
    135 		(void) snprintf(path, sizeof(path), "%s/%s.%d",
    136 				BINDINGDIR, dom, 2);
    137 		if ((fd = open(path, O_RDONLY)) == -1) {
    138 			/*
    139 			 * no binding file, YP is dead, or not yet fully
    140 			 * alive.
    141 			 */
    142 			goto trynet;
    143 		}
    144 		if (flock(fd, LOCK_EX | LOCK_NB) == -1 &&
    145 		    errno == EWOULDBLOCK) {
    146 			struct iovec    iov[2];
    147 			struct ypbind_resp ybr;
    148 			u_short         ypb_port;
    149 			struct ypbind_binding *bn;
    150 
    151 			iov[0].iov_base = &ypb_port;
    152 			iov[0].iov_len = sizeof ypb_port;
    153 			iov[1].iov_base = &ybr;
    154 			iov[1].iov_len = sizeof ybr;
    155 
    156 			r = readv(fd, iov, 2);
    157 			if (r != (ssize_t)(iov[0].iov_len + iov[1].iov_len)) {
    158 				(void)close(fd);
    159 				ysd->dom_vers = -1;
    160 				goto again;
    161 			}
    162 			(void)memset(&ysd->dom_server_addr, 0,
    163 				     sizeof ysd->dom_server_addr);
    164 			ysd->dom_server_addr.sin_len =
    165 				sizeof(struct sockaddr_in);
    166 			ysd->dom_server_addr.sin_family = AF_INET;
    167 			bn = &ybr.ypbind_respbody.ypbind_bindinfo;
    168 			ysd->dom_server_addr.sin_port =
    169 				bn->ypbind_binding_port;
    170 
    171 			ysd->dom_server_addr.sin_addr =
    172 				bn->ypbind_binding_addr;
    173 
    174 			ysd->dom_server_port = ysd->dom_server_addr.sin_port;
    175 			(void)close(fd);
    176 			goto gotit;
    177 		} else {
    178 			/* no lock on binding file, YP is dead. */
    179 			(void)close(fd);
    180 			if (new)
    181 				free(ysd);
    182 			return YPERR_YPBIND;
    183 		}
    184 	}
    185 trynet:
    186 	if (ysd->dom_vers == -1 || ysd->dom_vers == 0) {
    187 		struct ypbind_binding *bn;
    188 		(void)memset(&clnt_sin, 0, sizeof clnt_sin);
    189 		clnt_sin.sin_len = sizeof(struct sockaddr_in);
    190 		clnt_sin.sin_family = AF_INET;
    191 		clnt_sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
    192 
    193 		clnt_sock = RPC_ANYSOCK;
    194 		client = clnttcp_create(&clnt_sin, YPBINDPROG, YPBINDVERS,
    195 					&clnt_sock, 0, 0);
    196 		if (client == NULL) {
    197 			clnt_pcreateerror("clnttcp_create");
    198 			if (new)
    199 				free(ysd);
    200 			return YPERR_YPBIND;
    201 		}
    202 		r = clnt_call(client, (rpcproc_t)YPBINDPROC_DOMAIN,
    203 		    (xdrproc_t)xdr_ypdomain_wrap_string, &dom,
    204 		    (xdrproc_t)xdr_ypbind_resp, &ypbr, _yplib_timeout);
    205 		if (r != RPC_SUCCESS) {
    206 			if (new == 0 && ++nerrs == _yplib_nerrs) {
    207 				nerrs = 0;
    208 				fprintf(stderr,
    209 		    "YP server for domain %s not responding, still trying\n",
    210 				    dom);
    211 			}
    212 			clnt_destroy(client);
    213 			ysd->dom_vers = -1;
    214 			goto again;
    215 		}
    216 		clnt_destroy(client);
    217 
    218 		(void)memset(&ysd->dom_server_addr, 0,
    219 			     sizeof ysd->dom_server_addr);
    220 		ysd->dom_server_addr.sin_len = sizeof(struct sockaddr_in);
    221 		ysd->dom_server_addr.sin_family = AF_INET;
    222 		bn = &ypbr.ypbind_respbody.ypbind_bindinfo;
    223 		ysd->dom_server_addr.sin_port =
    224 			bn->ypbind_binding_port;
    225 		ysd->dom_server_addr.sin_addr.s_addr =
    226 			bn->ypbind_binding_addr.s_addr;
    227 		ysd->dom_server_port =
    228 			bn->ypbind_binding_port;
    229 gotit:
    230 		ysd->dom_vers = YPVERS;
    231 		(void)strlcpy(ysd->dom_domain, dom, sizeof(ysd->dom_domain));
    232 	}
    233 	if (ysd->dom_client)
    234 		clnt_destroy(ysd->dom_client);
    235 	ysd->dom_socket = RPC_ANYSOCK;
    236 	ysd->dom_client = clntudp_create(&ysd->dom_server_addr,
    237 	    YPPROG, YPVERS, _yplib_rpc_timeout, &ysd->dom_socket);
    238 	if (ysd->dom_client == NULL) {
    239 		clnt_pcreateerror("clntudp_create");
    240 		ysd->dom_vers = -1;
    241 		goto again;
    242 	}
    243 	if (fcntl(ysd->dom_socket, F_SETFD, 1) == -1)
    244 		perror("fcntl: F_SETFD");
    245 
    246 	if (new) {
    247 		ysd->dom_pnext = _ypbindlist;
    248 		_ypbindlist = ysd;
    249 	}
    250 	if (ypdb != NULL)
    251 		*ypdb = ysd;
    252 	return 0;
    253 }
    254 
    255 void
    256 __yp_unbind(ypb)
    257 	struct dom_binding *ypb;
    258 {
    259 
    260 	_DIAGASSERT(ypb != NULL);
    261 
    262 	clnt_destroy(ypb->dom_client);
    263 	ypb->dom_client = NULL;
    264 	ypb->dom_socket = -1;
    265 }
    266 
    267 int
    268 yp_bind(dom)
    269 	const char     *dom;
    270 {
    271 	if (_yp_invalid_domain(dom))
    272 		return YPERR_BADARGS;
    273 
    274 	return _yp_dobind(dom, NULL);
    275 }
    276 
    277 void
    278 yp_unbind(dom)
    279 	const char     *dom;
    280 {
    281 	struct dom_binding *ypb, *ypbp;
    282 
    283 	if (_yp_invalid_domain(dom))
    284 		return;
    285 
    286 	ypbp = NULL;
    287 	for (ypb = _ypbindlist; ypb; ypb = ypb->dom_pnext) {
    288 		if (strcmp(dom, ypb->dom_domain) == 0) {
    289 			clnt_destroy(ypb->dom_client);
    290 			if (ypbp)
    291 				ypbp->dom_pnext = ypb->dom_pnext;
    292 			else
    293 				_ypbindlist = ypb->dom_pnext;
    294 			free(ypb);
    295 			return;
    296 		}
    297 		ypbp = ypb;
    298 	}
    299 	return;
    300 }
    301 
    302 int
    303 yp_get_default_domain(domp)
    304 	char          **domp;
    305 {
    306 	if (domp == NULL)
    307 		return YPERR_BADARGS;
    308 	*domp = NULL;
    309 	if (_yp_domain[0] == '\0')
    310 		if (getdomainname(_yp_domain, sizeof _yp_domain))
    311 			return YPERR_NODOM;
    312 	*domp = _yp_domain;
    313 	return 0;
    314 }
    315 
    316 int
    317 _yp_check(dom)
    318 	char          **dom;
    319 {
    320 	char           *unused;
    321 
    322 	if (_yp_domain[0] == '\0')
    323 		if (yp_get_default_domain(&unused))
    324 			return 0;
    325 
    326 	if (dom)
    327 		*dom = _yp_domain;
    328 
    329 	if (yp_bind(_yp_domain) == 0)
    330 		return 1;
    331 	return 0;
    332 }
    333 
    334 /*
    335  * _yp_invalid_domain: check if given domainname isn't legal.
    336  * returns non-zero if invalid
    337  */
    338 int
    339 _yp_invalid_domain(dom)
    340 	const char *dom;
    341 {
    342 	if (dom == NULL || *dom == '\0')
    343 		return 1;
    344 
    345 	if (strlen(dom) > YPMAXDOMAIN)
    346 		return 1;
    347 
    348 	if (strchr(dom, '/') != NULL)
    349 		return 1;
    350 
    351 	return 0;
    352 }
    353