usr.sbin/ypbind/ypbind.c

   1 /*
   2  * Copyright (c) 1992/3 Theo de Raadt <deraadt@fsa.ca>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. The name of the author may not be used to endorse or promote
  14  *    products derived from this software without specific prior written
  15  *    permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
  18  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #include <sys/cdefs.h>
  31 __FBSDID("$FreeBSD$");
  32
  33 #include <sys/param.h>
  34 #include <sys/types.h>
  35 #include <sys/wait.h>
  36 #include <sys/ioctl.h>
  37 #include <sys/signal.h>
  38 #include <sys/socket.h>
  39 #include <sys/file.h>
  40 #include <sys/fcntl.h>
  41 #include <sys/stat.h>
  42 #include <sys/uio.h>
  43 #include <ctype.h>
  44 #include <dirent.h>
  45 #include <err.h>
  46 #include <errno.h>
  47 #include <netdb.h>
  48 #include <signal.h>
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <string.h>
  52 #include <syslog.h>
  53 #include <unistd.h>
  54 #include <rpc/rpc.h>
  55 #include <rpc/xdr.h>
  56 #include <net/if.h>
  57 #include <netinet/in.h>
  58 #include <arpa/inet.h>
  59 #include <rpc/pmap_clnt.h>
  60 #include <rpc/pmap_prot.h>
  61 #include <rpc/pmap_rmt.h>
  62 #include <rpc/rpc_com.h>
  63 #include <rpcsvc/yp.h>
  64 #include <rpcsvc/ypclnt.h>
  65 #include "yp_ping.h"
  66
  67 #ifndef BINDINGDIR
  68 #define BINDINGDIR "/var/yp/binding"
  69 #endif
  70
  71 #ifndef YPBINDLOCK
  72 #define YPBINDLOCK "/var/run/ypbind.lock"
  73 #endif
  74
  75 struct _dom_binding {
  76         struct _dom_binding *dom_pnext;
  77         char dom_domain[YPMAXDOMAIN + 1];
  78         struct sockaddr_in dom_server_addr;
  79         long int dom_vers;
  80         int dom_lockfd;
  81         int dom_alive;
  82         int dom_broadcast_pid;
  83         int dom_pipe_fds[2];
  84         int dom_default;
  85 };
  86
  87 #define READFD ypdb->dom_pipe_fds[0]
  88 #define WRITEFD ypdb->dom_pipe_fds[1]
  89 #define BROADFD broad_domain->dom_pipe_fds[1]
  90
  91 extern bool_t xdr_domainname(), xdr_ypbind_resp();
  92 extern bool_t xdr_ypreq_key(), xdr_ypresp_val();
  93 extern bool_t xdr_ypbind_setdom();
  94
  95 void    checkwork(void);
  96 void    *ypbindproc_null_2_yp(SVCXPRT *, void *, CLIENT *);
  97 void    *ypbindproc_setdom_2_yp(SVCXPRT *, struct ypbind_setdom *, CLIENT *);
  98 void    rpc_received(char *, struct sockaddr_in *, int);
  99 void    broadcast(struct _dom_binding *);
 100 int     ping(struct _dom_binding *);
 101 int     tell_parent(char *, struct sockaddr_in *);
 102 void    handle_children(struct _dom_binding *);
 103 void    reaper(int);
 104 void    terminate(int);
 105 void    yp_restricted_mode(char *);
 106 int     verify(struct in_addr);
 107
 108 char *domain_name;
 109 struct _dom_binding *ypbindlist;
 110 static struct _dom_binding *broad_domain;
 111
 112 #define YPSET_NO        0
 113 #define YPSET_LOCAL     1
 114 #define YPSET_ALL       2
 115 int ypsetmode = YPSET_NO;
 116 int ypsecuremode = 0;
 117 int ppid;
 118
 119 #define NOT_RESPONDING_HYSTERESIS 10
 120 static int not_responding_count = 0;
 121
 122 /*
 123  * Special restricted mode variables: when in restricted mode, only the
 124  * specified restricted_domain will be bound, and only the servers listed
 125  * in restricted_addrs will be used for binding.
 126  */
 127 #define RESTRICTED_SERVERS 10
 128 int yp_restricted = 0;
 129 int yp_manycast = 0;
 130 struct in_addr restricted_addrs[RESTRICTED_SERVERS];
 131
 132 /* No more than MAX_CHILDREN child broadcasters at a time. */
 133 #ifndef MAX_CHILDREN
 134 #define MAX_CHILDREN 5
 135 #endif
 136 /* No more than MAX_DOMAINS simultaneous domains */
 137 #ifndef MAX_DOMAINS
 138 #define MAX_DOMAINS 200
 139 #endif
 140 /* RPC timeout value */
 141 #ifndef FAIL_THRESHOLD
 142 #define FAIL_THRESHOLD 20
 143 #endif
 144
 145 /* Number of times to fish for a response froma particular set of hosts */
 146 #ifndef MAX_RETRIES
 147 #define MAX_RETRIES 30
 148 #endif
 149
 150 int retries = 0;
 151 int children = 0;
 152 int domains = 0;
 153 int yplockfd;
 154 fd_set fdsr;
 155
 156 SVCXPRT *udptransp, *tcptransp;
 157
 158 void *
 159 ypbindproc_null_2_yp(SVCXPRT *transp, void *argp, CLIENT *clnt)
 160 {
 161         static char res;
 162
 163         bzero(&res, sizeof(res));
 164         return &res;
 165 }
 166
 167 struct ypbind_resp *
 168 ypbindproc_domain_2_yp(SVCXPRT *transp, domainname *argp, CLIENT *clnt)
 169 {
 170         static struct ypbind_resp res;
 171         struct _dom_binding *ypdb;
 172         char path[MAXPATHLEN];
 173
 174         bzero(&res, sizeof res);
 175         res.ypbind_status = YPBIND_FAIL_VAL;
 176         res.ypbind_resp_u.ypbind_error = YPBIND_ERR_NOSERV;
 177
 178         if (strchr(*argp, '/')) {
 179                 syslog(LOG_WARNING, "Domain name '%s' has embedded slash -- \
 180 rejecting.", *argp);
 181                 return(&res);
 182         }
 183
 184         for (ypdb = ypbindlist; ypdb; ypdb = ypdb->dom_pnext) {
 185                 if (strcmp(ypdb->dom_domain, *argp) == 0)
 186                         break;
 187                 }
 188
 189         if (ypdb == NULL) {
 190                 if (yp_restricted) {
 191                         syslog(LOG_NOTICE, "Running in restricted mode -- request to bind domain \"%s\" rejected.\n", *argp);
 192                         return (&res);
 193                 }
 194
 195                 if (domains >= MAX_DOMAINS) {
 196                         syslog(LOG_WARNING, "domain limit (%d) exceeded",
 197                                                         MAX_DOMAINS);
 198                         res.ypbind_resp_u.ypbind_error = YPBIND_ERR_RESC;
 199                         return (&res);
 200                 }
 201                 ypdb = (struct _dom_binding *)malloc(sizeof *ypdb);
 202                 if (ypdb == NULL) {
 203                         syslog(LOG_WARNING, "malloc: %m");
 204                         res.ypbind_resp_u.ypbind_error = YPBIND_ERR_RESC;
 205                         return (&res);
 206                 }
 207                 bzero(ypdb, sizeof *ypdb);
 208                 strncpy(ypdb->dom_domain, *argp, sizeof ypdb->dom_domain);
 209                 ypdb->dom_vers = YPVERS;
 210                 ypdb->dom_alive = 0;
 211                 ypdb->dom_default = 0;
 212                 ypdb->dom_lockfd = -1;
 213                 sprintf(path, "%s/%s.%ld", BINDINGDIR,
 214                                         ypdb->dom_domain, ypdb->dom_vers);
 215                 unlink(path);
 216                 ypdb->dom_pnext = ypbindlist;
 217                 ypbindlist = ypdb;
 218                 domains++;
 219         }
 220
 221         if (ping(ypdb)) {
 222                 return (&res);
 223         }
 224
 225         res.ypbind_status = YPBIND_SUCC_VAL;
 226         res.ypbind_resp_u.ypbind_error = 0; /* Success */
 227         *(u_int32_t *)&res.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_addr =
 228                 ypdb->dom_server_addr.sin_addr.s_addr;
 229         *(u_short *)&res.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_port =
 230                 ypdb->dom_server_addr.sin_port;
 231         /*printf("domain %s at %s/%d\n", ypdb->dom_domain,
 232                 inet_ntoa(ypdb->dom_server_addr.sin_addr),
 233                 ntohs(ypdb->dom_server_addr.sin_port));*/
 234         return (&res);
 235 }
 236
 237 void *
 238 ypbindproc_setdom_2_yp(SVCXPRT *transp, ypbind_setdom *argp, CLIENT *clnt)
 239 {
 240         struct sockaddr_in *fromsin, bindsin;
 241         static char             *result = NULL;
 242
 243         if (strchr(argp->ypsetdom_domain, '/')) {
 244                 syslog(LOG_WARNING, "Domain name '%s' has embedded slash -- \
 245 rejecting.", argp->ypsetdom_domain);
 246                 return(NULL);
 247         }
 248         fromsin = svc_getcaller(transp);
 249
 250         switch (ypsetmode) {
 251         case YPSET_LOCAL:
 252                 if (fromsin->sin_addr.s_addr != htonl(INADDR_LOOPBACK)) {
 253                         svcerr_noprog(transp);
 254                         return(NULL);
 255                 }
 256                 break;
 257         case YPSET_ALL:
 258                 break;
 259         case YPSET_NO:
 260         default:
 261                 svcerr_noprog(transp);
 262                 return(NULL);
 263         }
 264
 265         if (ntohs(fromsin->sin_port) >= IPPORT_RESERVED) {
 266                 svcerr_noprog(transp);
 267                 return(NULL);
 268         }
 269
 270         if (argp->ypsetdom_vers != YPVERS) {
 271                 svcerr_noprog(transp);
 272                 return(NULL);
 273         }
 274
 275         bzero(&bindsin, sizeof bindsin);
 276         bindsin.sin_family = AF_INET;
 277         bindsin.sin_addr.s_addr = *(u_int32_t *)argp->ypsetdom_binding.ypbind_binding_addr;
 278         bindsin.sin_port = *(u_short *)argp->ypsetdom_binding.ypbind_binding_port;
 279         rpc_received(argp->ypsetdom_domain, &bindsin, 1);
 280
 281         return((void *) &result);
 282 }
 283
 284 void
 285 ypbindprog_2(struct svc_req *rqstp, register SVCXPRT *transp)
 286 {
 287         union {
 288                 domainname ypbindproc_domain_2_arg;
 289                 struct ypbind_setdom ypbindproc_setdom_2_arg;
 290         } argument;
 291         struct authunix_parms *creds;
 292         char *result;
 293         bool_t (*xdr_argument)(), (*xdr_result)();
 294         char *(*local)();
 295
 296         switch (rqstp->rq_proc) {
 297         case YPBINDPROC_NULL:
 298                 xdr_argument = xdr_void;
 299                 xdr_result = xdr_void;
 300                 local = (char *(*)()) ypbindproc_null_2_yp;
 301                 break;
 302
 303         case YPBINDPROC_DOMAIN:
 304                 xdr_argument = xdr_domainname;
 305                 xdr_result = xdr_ypbind_resp;
 306                 local = (char *(*)()) ypbindproc_domain_2_yp;
 307                 break;
 308
 309         case YPBINDPROC_SETDOM:
 310                 switch (rqstp->rq_cred.oa_flavor) {
 311                 case AUTH_UNIX:
 312                         creds = (struct authunix_parms *)rqstp->rq_clntcred;
 313                         if (creds->aup_uid != 0) {
 314                                 svcerr_auth(transp, AUTH_BADCRED);
 315                                 return;
 316                         }
 317                         break;
 318                 default:
 319                         svcerr_auth(transp, AUTH_TOOWEAK);
 320                         return;
 321                 }
 322
 323                 xdr_argument = xdr_ypbind_setdom;
 324                 xdr_result = xdr_void;
 325                 local = (char *(*)()) ypbindproc_setdom_2_yp;
 326                 break;
 327
 328         default:
 329                 svcerr_noproc(transp);
 330                 return;
 331         }
 332         bzero(&argument, sizeof(argument));
 333         if (!svc_getargs(transp, (xdrproc_t)xdr_argument, &argument)) {
 334                 svcerr_decode(transp);
 335                 return;
 336         }
 337         result = (*local)(transp, &argument, rqstp);
 338         if (result != NULL &&
 339             !svc_sendreply(transp, (xdrproc_t)xdr_result, result)) {
 340                 svcerr_systemerr(transp);
 341         }
 342         return;
 343 }
 344
 345 /* Jack the reaper */
 346 void
 347 reaper(int sig)
 348 {
 349         int st;
 350
 351         while (wait3(&st, WNOHANG, NULL) > 0)
 352                 children--;
 353 }
 354
 355 void
 356 terminate(int sig)
 357 {
 358         struct _dom_binding *ypdb;
 359         char path[MAXPATHLEN];
 360
 361         if (ppid != getpid())
 362                 exit(0);
 363
 364         for (ypdb = ypbindlist; ypdb; ypdb = ypdb->dom_pnext) {
 365                 close(ypdb->dom_lockfd);
 366                 if (ypdb->dom_broadcast_pid)
 367                         kill(ypdb->dom_broadcast_pid, SIGINT);
 368                 sprintf(path, "%s/%s.%ld", BINDINGDIR,
 369                         ypdb->dom_domain, ypdb->dom_vers);
 370                 unlink(path);
 371         }
 372         close(yplockfd);
 373         unlink(YPBINDLOCK);
 374         pmap_unset(YPBINDPROG, YPBINDVERS);
 375         exit(0);
 376 }
 377
 378 int
 379 main(int argc, char *argv[])
 380 {
 381         struct timeval tv;
 382         int i;
 383         DIR *dird;
 384         struct dirent *dirp;
 385         struct _dom_binding *ypdb, *next;
 386
 387         /* Check that another ypbind isn't already running. */
 388         if ((yplockfd = (open(YPBINDLOCK, O_RDONLY|O_CREAT, 0444))) == -1)
 389                 err(1, "%s", YPBINDLOCK);
 390
 391         if (flock(yplockfd, LOCK_EX|LOCK_NB) == -1 && errno == EWOULDBLOCK)
 392                 errx(1, "another ypbind is already running. Aborting");
 393
 394         /* XXX domainname will be overriden if we use restricted mode */
 395         yp_get_default_domain(&domain_name);
 396         if (domain_name[0] == '\0')
 397                 errx(1, "domainname not set. Aborting");
 398
 399         for (i = 1; i<argc; i++) {
 400                 if (strcmp("-ypset", argv[i]) == 0)
 401                         ypsetmode = YPSET_ALL;
 402                 else if (strcmp("-ypsetme", argv[i]) == 0)
 403                         ypsetmode = YPSET_LOCAL;
 404                 else if (strcmp("-s", argv[i]) == 0)
 405                         ypsecuremode++;
 406                 else if (strcmp("-S", argv[i]) == 0 && argc > i)
 407                         yp_restricted_mode(argv[++i]);
 408                 else if (strcmp("-m", argv[i]) == 0)
 409                         yp_manycast++;
 410                 else
 411                         errx(1, "unknown option: %s", argv[i]);
 412         }
 413
 414         /* blow away everything in BINDINGDIR (if it exists) */
 415
 416         if ((dird = opendir(BINDINGDIR)) != NULL) {
 417                 char path[MAXPATHLEN];
 418                 while ((dirp = readdir(dird)) != NULL)
 419                         if (strcmp(dirp->d_name, ".") &&
 420                             strcmp(dirp->d_name, "..")) {
 421                                 sprintf(path,"%s/%s",BINDINGDIR,dirp->d_name);
 422                                 unlink(path);
 423                         }
 424                 closedir(dird);
 425         }
 426
 427 #ifdef DAEMON
 428         if (daemon(0,0))
 429                 err(1, "fork");
 430 #endif
 431
 432         pmap_unset(YPBINDPROG, YPBINDVERS);
 433
 434         udptransp = svcudp_create(RPC_ANYSOCK);
 435         if (udptransp == NULL)
 436                 errx(1, "cannot create udp service");
 437         if (!svc_register(udptransp, YPBINDPROG, YPBINDVERS, ypbindprog_2,
 438             IPPROTO_UDP))
 439                 errx(1, "unable to register (YPBINDPROG, YPBINDVERS, udp)");
 440
 441         tcptransp = svctcp_create(RPC_ANYSOCK, 0, 0);
 442         if (tcptransp == NULL)
 443                 errx(1, "cannot create tcp service");
 444
 445         if (!svc_register(tcptransp, YPBINDPROG, YPBINDVERS, ypbindprog_2,
 446             IPPROTO_TCP))
 447                 errx(1, "unable to register (YPBINDPROG, YPBINDVERS, tcp)");
 448
 449         /* build initial domain binding, make it "unsuccessful" */
 450         ypbindlist = (struct _dom_binding *)malloc(sizeof *ypbindlist);
 451         if (ypbindlist == NULL)
 452                 errx(1, "malloc");
 453         bzero(ypbindlist, sizeof *ypbindlist);
 454         strncpy(ypbindlist->dom_domain, domain_name, sizeof ypbindlist->dom_domain);
 455         ypbindlist->dom_vers = YPVERS;
 456         ypbindlist->dom_alive = 0;
 457         ypbindlist->dom_lockfd = -1;
 458         ypbindlist->dom_default = 1;
 459         domains++;
 460
 461         signal(SIGCHLD, reaper);
 462         signal(SIGTERM, terminate);
 463
 464         ppid = getpid(); /* Remember who we are. */
 465
 466         openlog(argv[0], LOG_PID, LOG_DAEMON);
 467
 468         /* Kick off the default domain */
 469         broadcast(ypbindlist);
 470
 471         while (1) {
 472                 fdsr = svc_fdset;
 473
 474                 tv.tv_sec = 60;
 475                 tv.tv_usec = 0;
 476
 477                 switch (select(_rpc_dtablesize(), &fdsr, NULL, NULL, &tv)) {
 478                 case 0:
 479                         checkwork();
 480                         break;
 481                 case -1:
 482                         if (errno != EINTR)
 483                                 syslog(LOG_WARNING, "select: %m");
 484                         break;
 485                 default:
 486                         for (ypdb = ypbindlist; ypdb; ypdb = next) {
 487                                 next = ypdb->dom_pnext;
 488                                 if (READFD > 0 && FD_ISSET(READFD, &fdsr)) {
 489                                         handle_children(ypdb);
 490                                         if (children == (MAX_CHILDREN - 1))
 491                                                 checkwork();
 492                                 }
 493                         }
 494                         svc_getreqset(&fdsr);
 495                         break;
 496                 }
 497         }
 498
 499         /* NOTREACHED */
 500         exit(1);
 501 }
 502
 503 void
 504 checkwork(void)
 505 {
 506         struct _dom_binding *ypdb;
 507
 508         for (ypdb = ypbindlist; ypdb; ypdb = ypdb->dom_pnext)
 509                 ping(ypdb);
 510 }
 511
 512 /* The clnt_broadcast() callback mechanism sucks. */
 513
 514 /*
 515  * Receive results from broadcaster. Don't worry about passing
 516  * bogus info to rpc_received() -- it can handle it. Note that we
 517  * must be sure to invalidate the dom_pipe_fds descriptors here:
 518  * since descriptors can be re-used, we have to make sure we
 519  * don't mistake one of the RPC descriptors for one of the pipes.
 520  * What's weird is that forgetting to invalidate the pipe descriptors
 521  * doesn't always result in an error (otherwise I would have caught
 522  * the mistake much sooner), even though logically it should.
 523  */
 524 void
 525 handle_children(struct _dom_binding *ypdb)
 526 {
 527         char buf[YPMAXDOMAIN + 1];
 528         struct sockaddr_in addr;
 529         int d = 0, a = 0;
 530         struct _dom_binding *y, *prev = NULL;
 531         char path[MAXPATHLEN];
 532
 533         if ((d = read(READFD, &buf, sizeof(buf))) <= 0)
 534                 syslog(LOG_WARNING, "could not read from child: %m");
 535
 536         if ((a = read(READFD, &addr, sizeof(struct sockaddr_in))) < 0)
 537                 syslog(LOG_WARNING, "could not read from child: %m");
 538
 539         close(READFD);
 540         FD_CLR(READFD, &fdsr);
 541         FD_CLR(READFD, &svc_fdset);
 542         READFD = WRITEFD = -1;
 543         if (d > 0 && a > 0)
 544                 rpc_received(buf, &addr, 0);
 545         else {
 546                 for (y = ypbindlist; y; y = y->dom_pnext) {
 547                         if (y == ypdb)
 548                                 break;
 549                         prev = y;
 550                 }
 551                 switch (ypdb->dom_default) {
 552                 case 0:
 553                         if (prev == NULL)
 554                                 ypbindlist = y->dom_pnext;
 555                         else
 556                                 prev->dom_pnext = y->dom_pnext;
 557                         sprintf(path, "%s/%s.%ld", BINDINGDIR,
 558                                 ypdb->dom_domain, YPVERS);
 559                         close(ypdb->dom_lockfd);
 560                         unlink(path);
 561                         free(ypdb);
 562                         domains--;
 563                         return;
 564                 case 1:
 565                         ypdb->dom_broadcast_pid = 0;
 566                         ypdb->dom_alive = 0;
 567                         broadcast(ypdb);
 568                         return;
 569                 default:
 570                         break;
 571                 }
 572         }
 573
 574         return;
 575 }
 576
 577 /*
 578  * Send our dying words back to our parent before we perish.
 579  */
 580 int
 581 tell_parent(char *dom, struct sockaddr_in *addr)
 582 {
 583         char buf[YPMAXDOMAIN + 1];
 584         struct timeval timeout;
 585         fd_set fds;
 586
 587         timeout.tv_sec = 5;
 588         timeout.tv_usec = 0;
 589
 590         sprintf(buf, "%s", broad_domain->dom_domain);
 591         if (write(BROADFD, &buf, sizeof(buf)) < 0)
 592                 return(1);
 593
 594         /*
 595          * Stay in sync with parent: wait for it to read our first
 596          * message before sending the second.
 597          */
 598
 599         FD_ZERO(&fds);
 600         FD_SET(BROADFD, &fds);
 601         if (select(FD_SETSIZE, NULL, &fds, NULL, &timeout) == -1)
 602                 return(1);
 603         if (FD_ISSET(BROADFD, &fds)) {
 604                 if (write(BROADFD, addr, sizeof(struct sockaddr_in)) < 0)
 605                         return(1);
 606         } else {
 607                 return(1);
 608         }
 609
 610         close(BROADFD);
 611         return (0);
 612 }
 613
 614 bool_t broadcast_result(out, addr)
 615 bool_t *out;
 616 struct sockaddr_in *addr;
 617 {
 618         if (retries >= MAX_RETRIES) {
 619                 bzero(addr, sizeof(struct sockaddr_in));
 620                 if (tell_parent(broad_domain->dom_domain, addr))
 621                         syslog(LOG_WARNING, "lost connection to parent");
 622                 return (TRUE);
 623         }
 624
 625         if (yp_restricted && verify(addr->sin_addr)) {
 626                 retries++;
 627                 syslog(LOG_NOTICE, "NIS server at %s not in restricted mode access list -- rejecting.\n",inet_ntoa(addr->sin_addr));
 628                 return (FALSE);
 629         } else {
 630                 if (tell_parent(broad_domain->dom_domain, addr))
 631                         syslog(LOG_WARNING, "lost connection to parent");
 632                 return (TRUE);
 633         }
 634 }
 635
 636 /*
 637  * The right way to send RPC broadcasts.
 638  * Use the clnt_broadcast() RPC service. Unfortunately, clnt_broadcast()
 639  * blocks while waiting for replies, so we have to fork off separate
 640  * broadcaster processes that do the waiting and then transmit their
 641  * results back to the parent for processing. We also have to remember
 642  * to save the name of the domain we're trying to bind in a global
 643  * variable since clnt_broadcast() provides no way to pass things to
 644  * the 'eachresult' callback function.
 645  */
 646 void
 647 broadcast(struct _dom_binding *ypdb)
 648 {
 649         bool_t out = FALSE;
 650         enum clnt_stat stat;
 651
 652         if (children >= MAX_CHILDREN || ypdb->dom_broadcast_pid)
 653                 return;
 654
 655         if (pipe(ypdb->dom_pipe_fds) < 0) {
 656                 syslog(LOG_WARNING, "pipe: %m");
 657                 return;
 658         }
 659
 660         if (ypdb->dom_vers == -1 && (long)ypdb->dom_server_addr.sin_addr.s_addr) {
 661                 if (not_responding_count++ >= NOT_RESPONDING_HYSTERESIS) {
 662                         not_responding_count = NOT_RESPONDING_HYSTERESIS;
 663                         syslog(LOG_WARNING, "NIS server [%s] for domain \"%s\" not responding",
 664                             inet_ntoa(ypdb->dom_server_addr.sin_addr), ypdb->dom_domain);
 665                 }
 666         }
 667
 668         broad_domain = ypdb;
 669         flock(ypdb->dom_lockfd, LOCK_UN);
 670
 671         switch ((ypdb->dom_broadcast_pid = fork())) {
 672         case 0:
 673                 close(READFD);
 674                 signal(SIGCHLD, SIG_DFL);
 675                 signal(SIGTERM, SIG_DFL);
 676                 break;
 677         case -1:
 678                 syslog(LOG_WARNING, "fork: %m");
 679                 close(READFD);
 680                 close(WRITEFD);
 681                 return;
 682         default:
 683                 close(WRITEFD);
 684                 FD_SET(READFD, &svc_fdset);
 685                 children++;
 686                 return;
 687         }
 688
 689         /* Release all locks before doing anything else. */
 690         while (ypbindlist) {
 691                 close(ypbindlist->dom_lockfd);
 692                 ypbindlist = ypbindlist->dom_pnext;
 693         }
 694         close(yplockfd);
 695
 696         /*
 697          * Special 'many-cast' behavior. If we're in restricted mode,
 698          * we have a list of possible server addresses to try. What
 699          * we can do is transmit to each ypserv's YPPROC_DOMAIN_NONACK
 700          * procedure and time the replies. Whoever replies fastest
 701          * gets to be our server. Note that this is not a broadcast
 702          * operation: we transmit uni-cast datagrams only.
 703          */
 704         if (yp_restricted && yp_manycast) {
 705                 short                   port;
 706                 int                     i;
 707                 struct sockaddr_in      sin;
 708
 709                 i = __yp_ping(restricted_addrs, yp_restricted,
 710                                 ypdb->dom_domain, &port);
 711                 if (i == -1) {
 712                         bzero(&ypdb->dom_server_addr,
 713                             sizeof(struct sockaddr_in));
 714                         if (tell_parent(ypdb->dom_domain,
 715                                 &ypdb->dom_server_addr))
 716                         syslog(LOG_WARNING, "lost connection to parent");
 717                 } else {
 718                         bzero(&sin, sizeof(struct sockaddr_in));
 719                         bcopy(&restricted_addrs[i],
 720                             &sin.sin_addr, sizeof(struct in_addr));
 721                         sin.sin_family = AF_INET;
 722                         sin.sin_port = port;
 723                         if (tell_parent(broad_domain->dom_domain, &sin))
 724                                 syslog(LOG_WARNING,
 725                                         "lost connection to parent");
 726                 }
 727                 _exit(0);
 728         }
 729
 730         retries = 0;
 731
 732         {
 733                 char *ptr;
 734
 735                 ptr = ypdb->dom_domain;
 736                 stat = clnt_broadcast(YPPROG, YPVERS, YPPROC_DOMAIN_NONACK,
 737                         (xdrproc_t)xdr_domainname, &ptr,
 738                         (xdrproc_t)xdr_bool, &out,
 739                         (resultproc_t)broadcast_result);
 740         }
 741
 742         if (stat != RPC_SUCCESS) {
 743                 bzero(&ypdb->dom_server_addr,
 744                     sizeof(struct sockaddr_in));
 745                 if (tell_parent(ypdb->dom_domain, &ypdb->dom_server_addr))
 746                         syslog(LOG_WARNING, "lost connection to parent");
 747         }
 748
 749         _exit(0);
 750 }
 751
 752 /*
 753  * The right way to check if a server is alive.
 754  * Attempt to get a client handle pointing to the server and send a
 755  * YPPROC_DOMAIN. If we can't get a handle or we get a reply of FALSE,
 756  * we invalidate this binding entry and send out a broadcast to try to
 757  * establish a new binding. Note that we treat non-default domains
 758  * specially: once bound, we keep tabs on our server, but if it
 759  * goes away and fails to respond after one round of broadcasting, we
 760  * abandon it until a client specifically references it again. We make
 761  * every effort to keep our default domain bound, however, since we
 762  * need it to keep the system on its feet.
 763  */
 764 int
 765 ping(struct _dom_binding *ypdb)
 766 {
 767         bool_t out;
 768         struct timeval interval, timeout;
 769         enum clnt_stat stat;
 770         int rpcsock = RPC_ANYSOCK;
 771         CLIENT *client_handle;
 772
 773         interval.tv_sec = FAIL_THRESHOLD;
 774         interval.tv_usec = 0;
 775         timeout.tv_sec = FAIL_THRESHOLD;
 776         timeout.tv_usec = 0;
 777
 778         if (ypdb->dom_broadcast_pid)
 779                 return(1);
 780
 781         if ((client_handle = clntudp_bufcreate(&ypdb->dom_server_addr,
 782                 YPPROG, YPVERS, interval, &rpcsock, RPCSMALLMSGSIZE,
 783                 RPCSMALLMSGSIZE)) == (CLIENT *)NULL) {
 784                 /* Can't get a handle: we're dead. */
 785                 ypdb->dom_alive = 0;
 786                 ypdb->dom_vers = -1;
 787                 broadcast(ypdb);
 788                 return(1);
 789         }
 790
 791         {
 792                 char *ptr;
 793
 794                 ptr = ypdb->dom_domain;
 795
 796                 stat = clnt_call(client_handle, YPPROC_DOMAIN,
 797                     (xdrproc_t)xdr_domainname, &ptr,
 798                     (xdrproc_t)xdr_bool, &out, timeout);
 799                 if (stat != RPC_SUCCESS || out == FALSE) {
 800                         ypdb->dom_alive = 0;
 801                         ypdb->dom_vers = -1;
 802                         clnt_destroy(client_handle);
 803                         broadcast(ypdb);
 804                         return(1);
 805                 }
 806         }
 807
 808         clnt_destroy(client_handle);
 809         return(0);
 810 }
 811
 812 void
 813 rpc_received(char *dom, struct sockaddr_in *raddrp, int force)
 814 {
 815         struct _dom_binding *ypdb, *prev = NULL;
 816         struct iovec iov[2];
 817         struct ypbind_resp ybr;
 818         char path[MAXPATHLEN];
 819         int fd;
 820
 821         /*printf("returned from %s/%d about %s\n", inet_ntoa(raddrp->sin_addr),
 822                ntohs(raddrp->sin_port), dom);*/
 823
 824         if (dom == NULL)
 825                 return;
 826
 827         for (ypdb = ypbindlist; ypdb; ypdb = ypdb->dom_pnext) {
 828                 if (strcmp(ypdb->dom_domain, dom) == 0)
 829                         break;
 830                 prev = ypdb;
 831         }
 832
 833         if (ypdb && force) {
 834                 if (ypdb->dom_broadcast_pid) {
 835                         kill(ypdb->dom_broadcast_pid, SIGINT);
 836                         close(READFD);
 837                         FD_CLR(READFD, &fdsr);
 838                         FD_CLR(READFD, &svc_fdset);
 839                         READFD = WRITEFD = -1;
 840                 }
 841         }
 842
 843         /* if in secure mode, check originating port number */
 844         if ((ypsecuremode && (ntohs(raddrp->sin_port) >= IPPORT_RESERVED))) {
 845             syslog(LOG_WARNING, "Rejected NIS server on [%s/%d] for domain %s.",
 846                    inet_ntoa(raddrp->sin_addr), ntohs(raddrp->sin_port),
 847                    dom);
 848             if (ypdb != NULL) {
 849                 ypdb->dom_broadcast_pid = 0;
 850                 ypdb->dom_alive = 0;
 851             }
 852             return;
 853         }
 854
 855         if (raddrp->sin_addr.s_addr == (long)0) {
 856                 switch (ypdb->dom_default) {
 857                 case 0:
 858                         if (prev == NULL)
 859                                 ypbindlist = ypdb->dom_pnext;
 860                         else
 861                                 prev->dom_pnext = ypdb->dom_pnext;
 862                         sprintf(path, "%s/%s.%ld", BINDINGDIR,
 863                                 ypdb->dom_domain, YPVERS);
 864                         close(ypdb->dom_lockfd);
 865                         unlink(path);
 866                         free(ypdb);
 867                         domains--;
 868                         return;
 869                 case 1:
 870                         ypdb->dom_broadcast_pid = 0;
 871                         ypdb->dom_alive = 0;
 872                         broadcast(ypdb);
 873                         return;
 874                 default:
 875                         break;
 876                 }
 877         }
 878
 879         if (ypdb == NULL) {
 880                 if (force == 0)
 881                         return;
 882                 ypdb = (struct _dom_binding *)malloc(sizeof *ypdb);
 883                 if (ypdb == NULL) {
 884                         syslog(LOG_WARNING, "malloc: %m");
 885                         return;
 886                 }
 887                 bzero(ypdb, sizeof *ypdb);
 888                 strncpy(ypdb->dom_domain, dom, sizeof ypdb->dom_domain);
 889                 ypdb->dom_lockfd = -1;
 890                 ypdb->dom_default = 0;
 891                 ypdb->dom_pnext = ypbindlist;
 892                 ypbindlist = ypdb;
 893         }
 894
 895         /* We've recovered from a crash: inform the world. */
 896         if (ypdb->dom_vers == -1 && ypdb->dom_server_addr.sin_addr.s_addr) {
 897                 if (not_responding_count >= NOT_RESPONDING_HYSTERESIS) {
 898                         not_responding_count = 0;
 899                         syslog(LOG_WARNING, "NIS server [%s] for domain \"%s\" OK",
 900                             inet_ntoa(raddrp->sin_addr), ypdb->dom_domain);
 901                 }
 902         }
 903
 904         bcopy(raddrp, &ypdb->dom_server_addr,
 905                 sizeof ypdb->dom_server_addr);
 906
 907         ypdb->dom_vers = YPVERS;
 908         ypdb->dom_alive = 1;
 909         ypdb->dom_broadcast_pid = 0;
 910
 911         if (ypdb->dom_lockfd != -1)
 912                 close(ypdb->dom_lockfd);
 913
 914         sprintf(path, "%s/%s.%ld", BINDINGDIR,
 915                 ypdb->dom_domain, ypdb->dom_vers);
 916 #ifdef O_SHLOCK
 917         if ((fd = open(path, O_CREAT|O_SHLOCK|O_RDWR|O_TRUNC, 0644)) == -1) {
 918                 (void)mkdir(BINDINGDIR, 0755);
 919                 if ((fd = open(path, O_CREAT|O_SHLOCK|O_RDWR|O_TRUNC, 0644)) == -1)
 920                         return;
 921         }
 922 #else
 923         if ((fd = open(path, O_CREAT|O_RDWR|O_TRUNC, 0644)) == -1) {
 924                 (void)mkdir(BINDINGDIR, 0755);
 925                 if ((fd = open(path, O_CREAT|O_RDWR|O_TRUNC, 0644)) == -1)
 926                         return;
 927         }
 928         flock(fd, LOCK_SH);
 929 #endif
 930
 931         /*
 932          * ok, if BINDINGDIR exists, and we can create the binding file,
 933          * then write to it..
 934          */
 935         ypdb->dom_lockfd = fd;
 936
 937         iov[0].iov_base = (char *)&(udptransp->xp_port);
 938         iov[0].iov_len = sizeof udptransp->xp_port;
 939         iov[1].iov_base = (char *)&ybr;
 940         iov[1].iov_len = sizeof ybr;
 941
 942         bzero(&ybr, sizeof ybr);
 943         ybr.ypbind_status = YPBIND_SUCC_VAL;
 944         *(u_int32_t *)&ybr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_addr = raddrp->sin_addr.s_addr;
 945         *(u_short *)&ybr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_port = raddrp->sin_port;
 946
 947         if (writev(ypdb->dom_lockfd, iov, 2) != iov[0].iov_len + iov[1].iov_len) {
 948                 syslog(LOG_WARNING, "write: %m");
 949                 close(ypdb->dom_lockfd);
 950                 ypdb->dom_lockfd = -1;
 951                 return;
 952         }
 953 }
 954
 955 /*
 956  * Check address against list of allowed servers. Return 0 if okay,
 957  * 1 if not matched.
 958  */
 959 int
 960 verify(struct in_addr addr)
 961 {
 962         int i;
 963
 964         for (i = 0; i < RESTRICTED_SERVERS; i++)
 965                 if (!bcmp(&addr, &restricted_addrs[i], sizeof(struct in_addr)))
 966                         return(0);
 967
 968         return(1);
 969 }
 970
 971 /*
 972  * Try to set restricted mode. We default to normal mode if we can't
 973  * resolve the specified hostnames.
 974  */
 975 void
 976 yp_restricted_mode(char *args)
 977 {
 978         struct hostent *h;
 979         int i = 0;
 980         char *s;
 981
 982         /* Find the restricted domain. */
 983         if ((s = strsep(&args, ",")) == NULL)
 984                 return;
 985         domain_name = s;
 986
 987         /* Get the addresses of the servers. */
 988         while ((s = strsep(&args, ",")) != NULL && i < RESTRICTED_SERVERS) {
 989                 if ((h = gethostbyname(s)) == NULL)
 990                         return;
 991                 bcopy (h->h_addr_list[0], &restricted_addrs[i],
 992                     sizeof(struct in_addr));
 993                 i++;
 994         }
 995
 996         /* ypset and ypsetme not allowed with restricted mode */
 997         ypsetmode = YPSET_NO;
 998
 999         yp_restricted = i;
1000         return;
1001 }