sunrpc/svc.c

   1 /*
   2  * svc.c, Server-side remote procedure call interface.
   3  *
   4  * There are two sets of procedures here.  The xprt routines are
   5  * for handling transport handles.  The svc routines handle the
   6  * list of service routines.
   7  *  Copyright (C) 2002-2016 Free Software Foundation, Inc.
   8  *  This file is part of the GNU C Library.
   9  *  Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
  10  *
  11  *  The GNU C Library is free software; you can redistribute it and/or
  12  *  modify it under the terms of the GNU Lesser General Public
  13  *  License as published by the Free Software Foundation; either
  14  *  version 2.1 of the License, or (at your option) any later version.
  15  *
  16  *  The GNU C Library is distributed in the hope that it will be useful,
  17  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  *  Lesser General Public License for more details.
  20  *
  21  *  You should have received a copy of the GNU Lesser General Public
  22  *  License along with the GNU C Library; if not, see
  23  *  <http://www.gnu.org/licenses/>.
  24  *
  25  * Copyright (c) 2010, Oracle America, Inc.
  26  *
  27  * Redistribution and use in source and binary forms, with or without
  28  * modification, are permitted provided that the following conditions are
  29  * met:
  30  *
  31  *     * Redistributions of source code must retain the above copyright
  32  *       notice, this list of conditions and the following disclaimer.
  33  *     * Redistributions in binary form must reproduce the above
  34  *       copyright notice, this list of conditions and the following
  35  *       disclaimer in the documentation and/or other materials
  36  *       provided with the distribution.
  37  *     * Neither the name of the "Oracle America, Inc." nor the names of its
  38  *       contributors may be used to endorse or promote products derived
  39  *       from this software without specific prior written permission.
  40  *
  41  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  42  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  43  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  44  *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  45  *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
  46  *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  47  *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  48  *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  49  *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  50  *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  51  *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  52  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  53  */
  54
  55 #include <errno.h>
  56 #include <unistd.h>
  57 #include <rpc/rpc.h>
  58 #include <rpc/svc.h>
  59 #include <rpc/pmap_clnt.h>
  60 #include <sys/poll.h>
  61 #include <time.h>
  62
  63 #ifdef _RPC_THREAD_SAFE_
  64 #define xports RPC_THREAD_VARIABLE(svc_xports_s)
  65 #else
  66 static SVCXPRT **xports;
  67 #endif
  68
  69 #define NULL_SVC ((struct svc_callout *)0)
  70 #define RQCRED_SIZE     400     /* this size is excessive */
  71
  72 /* The services list
  73    Each entry represents a set of procedures (an rpc program).
  74    The dispatch routine takes request structs and runs the
  75    appropriate procedure. */
  76 struct svc_callout {
  77   struct svc_callout *sc_next;
  78   rpcprog_t sc_prog;
  79   rpcvers_t sc_vers;
  80   void (*sc_dispatch) (struct svc_req *, SVCXPRT *);
  81   bool_t sc_mapped;
  82 };
  83 #ifdef _RPC_THREAD_SAFE_
  84 #define svc_head RPC_THREAD_VARIABLE(svc_head_s)
  85 #else
  86 static struct svc_callout *svc_head;
  87 #endif
  88
  89 /* ***************  SVCXPRT related stuff **************** */
  90
  91 /* Activate a transport handle. */
  92 void
  93 xprt_register (SVCXPRT *xprt)
  94 {
  95   register int sock = xprt->xp_sock;
  96   register int i;
  97
  98   if (xports == NULL)
  99     {
 100       xports = (SVCXPRT **) calloc (_rpc_dtablesize (), sizeof (SVCXPRT *));
 101       if (xports == NULL) /* Don't add handle */
 102         return;
 103     }
 104
 105   if (sock < _rpc_dtablesize ())
 106     {
 107       struct pollfd *new_svc_pollfd;
 108
 109       xports[sock] = xprt;
 110       if (sock < FD_SETSIZE)
 111         FD_SET (sock, &svc_fdset);
 112
 113       /* Check if we have an empty slot */
 114       for (i = 0; i < svc_max_pollfd; ++i)
 115         if (svc_pollfd[i].fd == -1)
 116           {
 117             svc_pollfd[i].fd = sock;
 118             svc_pollfd[i].events = (POLLIN | POLLPRI |
 119                                     POLLRDNORM | POLLRDBAND);
 120             return;
 121           }
 122
 123       new_svc_pollfd = (struct pollfd *) realloc (svc_pollfd,
 124                                                   sizeof (struct pollfd)
 125                                                   * (svc_max_pollfd + 1));
 126       if (new_svc_pollfd == NULL) /* Out of memory */
 127         return;
 128       svc_pollfd = new_svc_pollfd;
 129       ++svc_max_pollfd;
 130
 131       svc_pollfd[svc_max_pollfd - 1].fd = sock;
 132       svc_pollfd[svc_max_pollfd - 1].events = (POLLIN | POLLPRI |
 133                                                POLLRDNORM | POLLRDBAND);
 134     }
 135 }
 136 libc_hidden_nolink_sunrpc (xprt_register, GLIBC_2_0)
 137
 138 /* De-activate a transport handle. */
 139 void
 140 xprt_unregister (SVCXPRT *xprt)
 141 {
 142   register int sock = xprt->xp_sock;
 143   register int i;
 144
 145   if ((sock < _rpc_dtablesize ()) && (xports[sock] == xprt))
 146     {
 147       xports[sock] = (SVCXPRT *) 0;
 148
 149       if (sock < FD_SETSIZE)
 150         FD_CLR (sock, &svc_fdset);
 151
 152       for (i = 0; i < svc_max_pollfd; ++i)
 153         if (svc_pollfd[i].fd == sock)
 154           svc_pollfd[i].fd = -1;
 155     }
 156 }
 157 #ifdef EXPORT_RPC_SYMBOLS
 158 libc_hidden_def (xprt_unregister)
 159 #else
 160 libc_hidden_nolink_sunrpc (xprt_unregister, GLIBC_2_0)
 161 #endif
 162
 163
 164 /* ********************** CALLOUT list related stuff ************* */
 165
 166 /* Search the callout list for a program number, return the callout
 167    struct. */
 168 static struct svc_callout *
 169 svc_find (rpcprog_t prog, rpcvers_t vers, struct svc_callout **prev)
 170 {
 171   register struct svc_callout *s, *p;
 172
 173   p = NULL_SVC;
 174   for (s = svc_head; s != NULL_SVC; s = s->sc_next)
 175     {
 176       if ((s->sc_prog == prog) && (s->sc_vers == vers))
 177         goto done;
 178       p = s;
 179     }
 180 done:
 181   *prev = p;
 182   return s;
 183 }
 184
 185
 186 static bool_t
 187 svc_is_mapped (rpcprog_t prog, rpcvers_t vers)
 188 {
 189   struct svc_callout *prev;
 190   register struct svc_callout *s;
 191   s = svc_find (prog, vers, &prev);
 192   return s!= NULL_SVC && s->sc_mapped;
 193 }
 194
 195
 196 /* Add a service program to the callout list.
 197    The dispatch routine will be called when a rpc request for this
 198    program number comes in. */
 199 bool_t
 200 svc_register (SVCXPRT * xprt, rpcprog_t prog, rpcvers_t vers,
 201               void (*dispatch) (struct svc_req *, SVCXPRT *),
 202               rpcproc_t protocol)
 203 {
 204   struct svc_callout *prev;
 205   register struct svc_callout *s;
 206
 207   if ((s = svc_find (prog, vers, &prev)) != NULL_SVC)
 208     {
 209       if (s->sc_dispatch == dispatch)
 210         goto pmap_it;           /* he is registering another xptr */
 211       return FALSE;
 212     }
 213   s = (struct svc_callout *) mem_alloc (sizeof (struct svc_callout));
 214   if (s == (struct svc_callout *) 0)
 215     return FALSE;
 216
 217   s->sc_prog = prog;
 218   s->sc_vers = vers;
 219   s->sc_dispatch = dispatch;
 220   s->sc_next = svc_head;
 221   s->sc_mapped = FALSE;
 222   svc_head = s;
 223
 224 pmap_it:
 225   /* now register the information with the local binder service */
 226   if (protocol)
 227     {
 228       if (! pmap_set (prog, vers, protocol, xprt->xp_port))
 229         return FALSE;
 230
 231       s->sc_mapped = TRUE;
 232     }
 233
 234   return TRUE;
 235 }
 236 #ifdef EXPORT_RPC_SYMBOLS
 237 libc_hidden_def (svc_register)
 238 #else
 239 libc_hidden_nolink_sunrpc (svc_register, GLIBC_2_0)
 240 #endif
 241
 242 /* Remove a service program from the callout list. */
 243 void
 244 svc_unregister (rpcprog_t prog, rpcvers_t vers)
 245 {
 246   struct svc_callout *prev;
 247   register struct svc_callout *s;
 248
 249   if ((s = svc_find (prog, vers, &prev)) == NULL_SVC)
 250     return;
 251
 252   if (prev == NULL_SVC)
 253     svc_head = s->sc_next;
 254   else
 255     prev->sc_next = s->sc_next;
 256
 257   s->sc_next = NULL_SVC;
 258   mem_free ((char *) s, (u_int) sizeof (struct svc_callout));
 259   /* now unregister the information with the local binder service */
 260   if (! svc_is_mapped (prog, vers))
 261     pmap_unset (prog, vers);
 262 }
 263 libc_hidden_nolink_sunrpc (svc_unregister, GLIBC_2_0)
 264
 265 /* ******************* REPLY GENERATION ROUTINES  ************ */
 266
 267 /* Send a reply to an rpc request */
 268 bool_t
 269 svc_sendreply (register SVCXPRT *xprt, xdrproc_t xdr_results,
 270                caddr_t xdr_location)
 271 {
 272   struct rpc_msg rply;
 273
 274   rply.rm_direction = REPLY;
 275   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 276   rply.acpted_rply.ar_verf = xprt->xp_verf;
 277   rply.acpted_rply.ar_stat = SUCCESS;
 278   rply.acpted_rply.ar_results.where = xdr_location;
 279   rply.acpted_rply.ar_results.proc = xdr_results;
 280   return SVC_REPLY (xprt, &rply);
 281 }
 282 #ifdef EXPORT_RPC_SYMBOLS
 283 libc_hidden_def (svc_sendreply)
 284 #else
 285 libc_hidden_nolink_sunrpc (svc_sendreply, GLIBC_2_0)
 286 #endif
 287
 288 /* No procedure error reply */
 289 void
 290 svcerr_noproc (register SVCXPRT *xprt)
 291 {
 292   struct rpc_msg rply;
 293
 294   rply.rm_direction = REPLY;
 295   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 296   rply.acpted_rply.ar_verf = xprt->xp_verf;
 297   rply.acpted_rply.ar_stat = PROC_UNAVAIL;
 298   SVC_REPLY (xprt, &rply);
 299 }
 300 #ifdef EXPORT_RPC_SYMBOLS
 301 libc_hidden_def (svcerr_noproc)
 302 #else
 303 libc_hidden_nolink_sunrpc (svcerr_noproc, GLIBC_2_0)
 304 #endif
 305
 306 /* Can't decode args error reply */
 307 void
 308 svcerr_decode (register SVCXPRT *xprt)
 309 {
 310   struct rpc_msg rply;
 311
 312   rply.rm_direction = REPLY;
 313   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 314   rply.acpted_rply.ar_verf = xprt->xp_verf;
 315   rply.acpted_rply.ar_stat = GARBAGE_ARGS;
 316   SVC_REPLY (xprt, &rply);
 317 }
 318 #ifdef EXPORT_RPC_SYMBOLS
 319 libc_hidden_def (svcerr_decode)
 320 #else
 321 libc_hidden_nolink_sunrpc (svcerr_decode, GLIBC_2_0)
 322 #endif
 323
 324 /* Some system error */
 325 void
 326 svcerr_systemerr (register SVCXPRT *xprt)
 327 {
 328   struct rpc_msg rply;
 329
 330   rply.rm_direction = REPLY;
 331   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 332   rply.acpted_rply.ar_verf = xprt->xp_verf;
 333   rply.acpted_rply.ar_stat = SYSTEM_ERR;
 334   SVC_REPLY (xprt, &rply);
 335 }
 336 #ifdef EXPORT_RPC_SYMBOLS
 337 libc_hidden_def (svcerr_systemerr)
 338 #else
 339 libc_hidden_nolink_sunrpc (svcerr_systemerr, GLIBC_2_0)
 340 #endif
 341
 342 /* Authentication error reply */
 343 void
 344 svcerr_auth (SVCXPRT *xprt, enum auth_stat why)
 345 {
 346   struct rpc_msg rply;
 347
 348   rply.rm_direction = REPLY;
 349   rply.rm_reply.rp_stat = MSG_DENIED;
 350   rply.rjcted_rply.rj_stat = AUTH_ERROR;
 351   rply.rjcted_rply.rj_why = why;
 352   SVC_REPLY (xprt, &rply);
 353 }
 354 libc_hidden_nolink_sunrpc (svcerr_auth, GLIBC_2_0)
 355
 356 /* Auth too weak error reply */
 357 void
 358 svcerr_weakauth (SVCXPRT *xprt)
 359 {
 360   svcerr_auth (xprt, AUTH_TOOWEAK);
 361 }
 362 libc_hidden_nolink_sunrpc (svcerr_weakauth, GLIBC_2_0)
 363
 364 /* Program unavailable error reply */
 365 void
 366 svcerr_noprog (register SVCXPRT *xprt)
 367 {
 368   struct rpc_msg rply;
 369
 370   rply.rm_direction = REPLY;
 371   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 372   rply.acpted_rply.ar_verf = xprt->xp_verf;
 373   rply.acpted_rply.ar_stat = PROG_UNAVAIL;
 374   SVC_REPLY (xprt, &rply);
 375 }
 376 libc_hidden_nolink_sunrpc (svcerr_noprog, GLIBC_2_0)
 377
 378 /* Program version mismatch error reply */
 379 void
 380 svcerr_progvers (register SVCXPRT *xprt, rpcvers_t low_vers,
 381                  rpcvers_t high_vers)
 382 {
 383   struct rpc_msg rply;
 384
 385   rply.rm_direction = REPLY;
 386   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 387   rply.acpted_rply.ar_verf = xprt->xp_verf;
 388   rply.acpted_rply.ar_stat = PROG_MISMATCH;
 389   rply.acpted_rply.ar_vers.low = low_vers;
 390   rply.acpted_rply.ar_vers.high = high_vers;
 391   SVC_REPLY (xprt, &rply);
 392 }
 393 libc_hidden_nolink_sunrpc (svcerr_progvers, GLIBC_2_0)
 394
 395 /* ******************* SERVER INPUT STUFF ******************* */
 396
 397 /*
 398  * Get server side input from some transport.
 399  *
 400  * Statement of authentication parameters management:
 401  * This function owns and manages all authentication parameters, specifically
 402  * the "raw" parameters (msg.rm_call.cb_cred and msg.rm_call.cb_verf) and
 403  * the "cooked" credentials (rqst->rq_clntcred).
 404  * However, this function does not know the structure of the cooked
 405  * credentials, so it make the following assumptions:
 406  *   a) the structure is contiguous (no pointers), and
 407  *   b) the cred structure size does not exceed RQCRED_SIZE bytes.
 408  * In all events, all three parameters are freed upon exit from this routine.
 409  * The storage is trivially management on the call stack in user land, but
 410  * is mallocated in kernel land.
 411  */
 412
 413 void
 414 svc_getreq (int rdfds)
 415 {
 416   fd_set readfds;
 417
 418   FD_ZERO (&readfds);
 419   readfds.fds_bits[0] = rdfds;
 420   svc_getreqset (&readfds);
 421 }
 422 libc_hidden_nolink_sunrpc (svc_getreq, GLIBC_2_0)
 423
 424 void
 425 svc_getreqset (fd_set *readfds)
 426 {
 427   register fd_mask mask;
 428   register fd_mask *maskp;
 429   register int setsize;
 430   register int sock;
 431   register int bit;
 432
 433   setsize = _rpc_dtablesize ();
 434   if (setsize > FD_SETSIZE)
 435     setsize = FD_SETSIZE;
 436   maskp = readfds->fds_bits;
 437   for (sock = 0; sock < setsize; sock += NFDBITS)
 438     for (mask = *maskp++; (bit = ffsl (mask)); mask ^= (1L << (bit - 1)))
 439       svc_getreq_common (sock + bit - 1);
 440 }
 441 libc_hidden_nolink_sunrpc (svc_getreqset, GLIBC_2_0)
 442
 443 void
 444 svc_getreq_poll (struct pollfd *pfdp, int pollretval)
 445 {
 446   if (pollretval == 0)
 447     return;
 448
 449   register int fds_found;
 450   for (int i = fds_found = 0; i < svc_max_pollfd; ++i)
 451     {
 452       register struct pollfd *p = &pfdp[i];
 453
 454       if (p->fd != -1 && p->revents)
 455         {
 456           /* fd has input waiting */
 457           if (p->revents & POLLNVAL)
 458             xprt_unregister (xports[p->fd]);
 459           else
 460             svc_getreq_common (p->fd);
 461
 462           if (++fds_found >= pollretval)
 463             break;
 464         }
 465     }
 466 }
 467 #ifdef EXPORT_RPC_SYMBOLS
 468 libc_hidden_def (svc_getreq_poll)
 469 #else
 470 libc_hidden_nolink_sunrpc (svc_getreq_poll, GLIBC_2_2)
 471 #endif
 472
 473
 474 void
 475 svc_getreq_common (const int fd)
 476 {
 477   enum xprt_stat stat;
 478   struct rpc_msg msg;
 479   register SVCXPRT *xprt;
 480   char cred_area[2 * MAX_AUTH_BYTES + RQCRED_SIZE];
 481   msg.rm_call.cb_cred.oa_base = cred_area;
 482   msg.rm_call.cb_verf.oa_base = &(cred_area[MAX_AUTH_BYTES]);
 483
 484   xprt = xports[fd];
 485   /* Do we control fd? */
 486   if (xprt == NULL)
 487      return;
 488
 489   /* now receive msgs from xprtprt (support batch calls) */
 490   do
 491     {
 492       if (SVC_RECV (xprt, &msg))
 493         {
 494           /* now find the exported program and call it */
 495           struct svc_callout *s;
 496           struct svc_req r;
 497           enum auth_stat why;
 498           rpcvers_t low_vers;
 499           rpcvers_t high_vers;
 500           int prog_found;
 501
 502           r.rq_clntcred = &(cred_area[2 * MAX_AUTH_BYTES]);
 503           r.rq_xprt = xprt;
 504           r.rq_prog = msg.rm_call.cb_prog;
 505           r.rq_vers = msg.rm_call.cb_vers;
 506           r.rq_proc = msg.rm_call.cb_proc;
 507           r.rq_cred = msg.rm_call.cb_cred;
 508
 509           /* first authenticate the message */
 510           /* Check for null flavor and bypass these calls if possible */
 511
 512           if (msg.rm_call.cb_cred.oa_flavor == AUTH_NULL)
 513             {
 514               r.rq_xprt->xp_verf.oa_flavor = _null_auth.oa_flavor;
 515               r.rq_xprt->xp_verf.oa_length = 0;
 516             }
 517           else if ((why = _authenticate (&r, &msg)) != AUTH_OK)
 518             {
 519               svcerr_auth (xprt, why);
 520               goto call_done;
 521             }
 522
 523           /* now match message with a registered service */
 524           prog_found = FALSE;
 525           low_vers = 0 - 1;
 526           high_vers = 0;
 527
 528           for (s = svc_head; s != NULL_SVC; s = s->sc_next)
 529             {
 530               if (s->sc_prog == r.rq_prog)
 531                 {
 532                   if (s->sc_vers == r.rq_vers)
 533                     {
 534                       (*s->sc_dispatch) (&r, xprt);
 535                       goto call_done;
 536                     }
 537                   /* found correct version */
 538                   prog_found = TRUE;
 539                   if (s->sc_vers < low_vers)
 540                     low_vers = s->sc_vers;
 541                   if (s->sc_vers > high_vers)
 542                     high_vers = s->sc_vers;
 543                 }
 544               /* found correct program */
 545             }
 546           /* if we got here, the program or version
 547              is not served ... */
 548           if (prog_found)
 549             svcerr_progvers (xprt, low_vers, high_vers);
 550           else
 551             svcerr_noprog (xprt);
 552           /* Fall through to ... */
 553         }
 554     call_done:
 555       if ((stat = SVC_STAT (xprt)) == XPRT_DIED)
 556         {
 557           SVC_DESTROY (xprt);
 558           break;
 559         }
 560     }
 561   while (stat == XPRT_MOREREQS);
 562 }
 563 libc_hidden_nolink_sunrpc (svc_getreq_common, GLIBC_2_2)
 564
 565 /* If there are no file descriptors available, then accept will fail.
 566    We want to delay here so the connection request can be dequeued;
 567    otherwise we can bounce between polling and accepting, never giving the
 568    request a chance to dequeue and eating an enormous amount of cpu time
 569    in svc_run if we're polling on many file descriptors.  */
 570 void
 571 __svc_accept_failed (void)
 572 {
 573   if (errno == EMFILE)
 574     {
 575       struct timespec ts = { .tv_sec = 0, .tv_nsec = 50000000 };
 576       __nanosleep (&ts, NULL);
 577     }
 578 }
 579
 580 #ifdef _RPC_THREAD_SAFE_
 581
 582 void
 583 __rpc_thread_svc_cleanup (void)
 584 {
 585   struct svc_callout *svcp;
 586
 587   while ((svcp = svc_head) != NULL)
 588     svc_unregister (svcp->sc_prog, svcp->sc_vers);
 589 }
 590
 591 #endif /* _RPC_THREAD_SAFE_ */