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yplib.c revision 1.26
      1 /*	$NetBSD: yplib.c,v 1.26 1997/01/21 20:40:07 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 #if defined(LIBC_SCCS) && !defined(lint)
     35 static char rcsid[] = "$NetBSD: yplib.c,v 1.26 1997/01/21 20:40:07 thorpej Exp $";
     36 #endif
     37 
     38 #include <sys/param.h>
     39 #include <sys/types.h>
     40 #include <sys/socket.h>
     41 #include <sys/file.h>
     42 #include <sys/uio.h>
     43 #include <errno.h>
     44 #include <stdio.h>
     45 #include <stdlib.h>
     46 #include <string.h>
     47 #include <unistd.h>
     48 #include <rpc/rpc.h>
     49 #include <rpc/xdr.h>
     50 #include <rpcsvc/yp_prot.h>
     51 #include <rpcsvc/ypclnt.h>
     52 
     53 #define BINDINGDIR	"/var/yp/binding"
     54 #define YPBINDLOCK	"/var/run/ypbind.lock"
     55 
     56 struct dom_binding *_ypbindlist;
     57 char _yp_domain[MAXHOSTNAMELEN];
     58 
     59 #define YPLIB_TIMEOUT		10
     60 #define YPLIB_RPC_RETRIES	4
     61 
     62 struct timeval _yplib_timeout = { YPLIB_TIMEOUT, 0 };
     63 struct timeval _yplib_rpc_timeout = { YPLIB_TIMEOUT / YPLIB_RPC_RETRIES,
     64 	1000000 * (YPLIB_TIMEOUT % YPLIB_RPC_RETRIES) / YPLIB_RPC_RETRIES };
     65 int _yplib_nerrs = 5;
     66 
     67 void _yp_unbind __P((struct dom_binding *));
     68 
     69 int
     70 _yp_dobind(dom, ypdb)
     71 	const char     *dom;
     72 	struct dom_binding **ypdb;
     73 {
     74 	static int      pid = -1;
     75 	char            path[MAXPATHLEN];
     76 	struct dom_binding *ysd, *ysd2;
     77 	struct ypbind_resp ypbr;
     78 	struct sockaddr_in clnt_sin;
     79 	int             clnt_sock, fd, gpid;
     80 	CLIENT         *client;
     81 	int             new = 0, r;
     82 	int             nerrs = 0;
     83 
     84 	if (dom == NULL || *dom == 0)
     85 		return YPERR_BADARGS;
     86 
     87 	/*
     88 	 * test if YP is running or not
     89 	 */
     90 	if ((fd = open(YPBINDLOCK, O_RDONLY)) == -1)
     91 		return YPERR_YPBIND;
     92 	if (!(flock(fd, LOCK_EX | LOCK_NB) == -1 && errno == EWOULDBLOCK)) {
     93 		(void)close(fd);
     94 		return YPERR_YPBIND;
     95 	}
     96 	(void)close(fd);
     97 
     98 	gpid = getpid();
     99 	if (!(pid == -1 || pid == gpid)) {
    100 		ysd = _ypbindlist;
    101 		while (ysd) {
    102 			if (ysd->dom_client)
    103 				clnt_destroy(ysd->dom_client);
    104 			ysd2 = ysd->dom_pnext;
    105 			free(ysd);
    106 			ysd = ysd2;
    107 		}
    108 		_ypbindlist = NULL;
    109 	}
    110 	pid = gpid;
    111 
    112 	if (ypdb != NULL)
    113 		*ypdb = NULL;
    114 
    115 	for (ysd = _ypbindlist; ysd; ysd = ysd->dom_pnext)
    116 		if (strcmp(dom, ysd->dom_domain) == 0)
    117 			break;
    118 	if (ysd == NULL) {
    119 		if ((ysd = malloc(sizeof *ysd)) == NULL)
    120 			return YPERR_YPERR;
    121 		(void)memset(ysd, 0, sizeof *ysd);
    122 		ysd->dom_socket = -1;
    123 		ysd->dom_vers = 0;
    124 		new = 1;
    125 	}
    126 again:
    127 	if (ysd->dom_vers == 0) {
    128 		(void) snprintf(path, sizeof(path), "%s/%s.%d",
    129 				BINDINGDIR, dom, 2);
    130 		if ((fd = open(path, O_RDONLY)) == -1) {
    131 			/*
    132 			 * no binding file, YP is dead, or not yet fully
    133 			 * alive.
    134 			 */
    135 			goto trynet;
    136 		}
    137 		if (flock(fd, LOCK_EX | LOCK_NB) == -1 &&
    138 		    errno == EWOULDBLOCK) {
    139 			struct iovec    iov[2];
    140 			struct ypbind_resp ybr;
    141 			u_short         ypb_port;
    142 			struct ypbind_binding *bn;
    143 
    144 			iov[0].iov_base = (caddr_t) & ypb_port;
    145 			iov[0].iov_len = sizeof ypb_port;
    146 			iov[1].iov_base = (caddr_t) & ybr;
    147 			iov[1].iov_len = sizeof ybr;
    148 
    149 			r = readv(fd, iov, 2);
    150 			if (r != iov[0].iov_len + iov[1].iov_len) {
    151 				(void)close(fd);
    152 				ysd->dom_vers = -1;
    153 				goto again;
    154 			}
    155 			(void)memset(&ysd->dom_server_addr, 0,
    156 				     sizeof ysd->dom_server_addr);
    157 			ysd->dom_server_addr.sin_len =
    158 				sizeof(struct sockaddr_in);
    159 			ysd->dom_server_addr.sin_family = AF_INET;
    160 			bn = &ybr.ypbind_respbody.ypbind_bindinfo;
    161 			ysd->dom_server_addr.sin_port =
    162 				bn->ypbind_binding_port;
    163 
    164 			ysd->dom_server_addr.sin_addr =
    165 				bn->ypbind_binding_addr;
    166 
    167 			ysd->dom_server_port = ysd->dom_server_addr.sin_port;
    168 			(void)close(fd);
    169 			goto gotit;
    170 		} else {
    171 			/* no lock on binding file, YP is dead. */
    172 			(void)close(fd);
    173 			if (new)
    174 				free(ysd);
    175 			return YPERR_YPBIND;
    176 		}
    177 	}
    178 trynet:
    179 	if (ysd->dom_vers == -1 || ysd->dom_vers == 0) {
    180 		struct ypbind_binding *bn;
    181 		(void)memset(&clnt_sin, 0, sizeof clnt_sin);
    182 		clnt_sin.sin_len = sizeof(struct sockaddr_in);
    183 		clnt_sin.sin_family = AF_INET;
    184 		clnt_sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
    185 
    186 		clnt_sock = RPC_ANYSOCK;
    187 		client = clnttcp_create(&clnt_sin, YPBINDPROG, YPBINDVERS,
    188 					&clnt_sock, 0, 0);
    189 		if (client == NULL) {
    190 			clnt_pcreateerror("clnttcp_create");
    191 			if (new)
    192 				free(ysd);
    193 			return YPERR_YPBIND;
    194 		}
    195 		r = clnt_call(client, YPBINDPROC_DOMAIN,
    196 		    xdr_ypdomain_wrap_string, &dom, xdr_ypbind_resp,
    197 		    &ypbr, _yplib_timeout);
    198 		if (r != RPC_SUCCESS) {
    199 			if (new == 0 && ++nerrs == _yplib_nerrs) {
    200 				nerrs = 0;
    201 				fprintf(stderr,
    202 		    "YP server for domain %s not responding, still trying\n",
    203 				    dom);
    204 			}
    205 			clnt_destroy(client);
    206 			ysd->dom_vers = -1;
    207 			goto again;
    208 		}
    209 		clnt_destroy(client);
    210 
    211 		(void)memset(&ysd->dom_server_addr, 0,
    212 			     sizeof ysd->dom_server_addr);
    213 		ysd->dom_server_addr.sin_len = sizeof(struct sockaddr_in);
    214 		ysd->dom_server_addr.sin_family = AF_INET;
    215 		bn = &ypbr.ypbind_respbody.ypbind_bindinfo;
    216 		ysd->dom_server_addr.sin_port =
    217 			bn->ypbind_binding_port;
    218 		ysd->dom_server_addr.sin_addr.s_addr =
    219 			bn->ypbind_binding_addr.s_addr;
    220 		ysd->dom_server_port =
    221 			bn->ypbind_binding_port;
    222 gotit:
    223 		ysd->dom_vers = YPVERS;
    224 		(void)strcpy(ysd->dom_domain, dom);
    225 	}
    226 	if (ysd->dom_client)
    227 		clnt_destroy(ysd->dom_client);
    228 	ysd->dom_socket = RPC_ANYSOCK;
    229 	ysd->dom_client = clntudp_create(&ysd->dom_server_addr,
    230 	    YPPROG, YPVERS, _yplib_rpc_timeout, &ysd->dom_socket);
    231 	if (ysd->dom_client == NULL) {
    232 		clnt_pcreateerror("clntudp_create");
    233 		ysd->dom_vers = -1;
    234 		goto again;
    235 	}
    236 	if (fcntl(ysd->dom_socket, F_SETFD, 1) == -1)
    237 		perror("fcntl: F_SETFD");
    238 
    239 	if (new) {
    240 		ysd->dom_pnext = _ypbindlist;
    241 		_ypbindlist = ysd;
    242 	}
    243 	if (ypdb != NULL)
    244 		*ypdb = ysd;
    245 	return 0;
    246 }
    247 
    248 void
    249 _yp_unbind(ypb)
    250 	struct dom_binding *ypb;
    251 {
    252 	clnt_destroy(ypb->dom_client);
    253 	ypb->dom_client = NULL;
    254 	ypb->dom_socket = -1;
    255 }
    256 
    257 int
    258 yp_bind(dom)
    259 	const char     *dom;
    260 {
    261 	return _yp_dobind(dom, NULL);
    262 }
    263 
    264 void
    265 yp_unbind(dom)
    266 	const char     *dom;
    267 {
    268 	struct dom_binding *ypb, *ypbp;
    269 
    270 	ypbp = NULL;
    271 	for (ypb = _ypbindlist; ypb; ypb = ypb->dom_pnext) {
    272 		if (strcmp(dom, ypb->dom_domain) == 0) {
    273 			clnt_destroy(ypb->dom_client);
    274 			if (ypbp)
    275 				ypbp->dom_pnext = ypb->dom_pnext;
    276 			else
    277 				_ypbindlist = ypb->dom_pnext;
    278 			free(ypb);
    279 			return;
    280 		}
    281 		ypbp = ypb;
    282 	}
    283 	return;
    284 }
    285 
    286 int
    287 yp_get_default_domain(domp)
    288 	char          **domp;
    289 {
    290 	*domp = NULL;
    291 	if (_yp_domain[0] == '\0')
    292 		if (getdomainname(_yp_domain, sizeof _yp_domain))
    293 			return YPERR_NODOM;
    294 	*domp = _yp_domain;
    295 	return 0;
    296 }
    297 
    298 int
    299 _yp_check(dom)
    300 	char          **dom;
    301 {
    302 	char           *unused;
    303 
    304 	if (_yp_domain[0] == '\0')
    305 		if (yp_get_default_domain(&unused))
    306 			return 0;
    307 
    308 	if (dom)
    309 		*dom = _yp_domain;
    310 
    311 	if (yp_bind(_yp_domain) == 0)
    312 		return 1;
    313 	return 0;
    314 }
    315