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) 2002-2017 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 /* Add a service program to the callout list.
 186    The dispatch routine will be called when a rpc request for this
 187    program number comes in. */
 188 bool_t
 189 svc_register (SVCXPRT * xprt, rpcprog_t prog, rpcvers_t vers,
 190               void (*dispatch) (struct svc_req *, SVCXPRT *),
 191               rpcproc_t protocol)
 192 {
 193   struct svc_callout *prev;
 194   register struct svc_callout *s;
 195
 196   if ((s = svc_find (prog, vers, &prev)) != NULL_SVC)
 197     {
 198       if (s->sc_dispatch == dispatch)
 199         goto pmap_it;           /* he is registering another xptr */
 200       return FALSE;
 201     }
 202   s = (struct svc_callout *) mem_alloc (sizeof (struct svc_callout));
 203   if (s == (struct svc_callout *) 0)
 204     return FALSE;
 205
 206   s->sc_prog = prog;
 207   s->sc_vers = vers;
 208   s->sc_dispatch = dispatch;
 209   s->sc_next = svc_head;
 210   s->sc_mapped = FALSE;
 211   svc_head = s;
 212
 213 pmap_it:
 214   /* now register the information with the local binder service */
 215   if (protocol)
 216     {
 217       if (! pmap_set (prog, vers, protocol, xprt->xp_port))
 218         return FALSE;
 219
 220       s->sc_mapped = TRUE;
 221     }
 222
 223   return TRUE;
 224 }
 225 #ifdef EXPORT_RPC_SYMBOLS
 226 libc_hidden_def (svc_register)
 227 #else
 228 libc_hidden_nolink_sunrpc (svc_register, GLIBC_2_0)
 229 #endif
 230
 231 /* Remove a service program from the callout list. */
 232 void
 233 svc_unregister (rpcprog_t prog, rpcvers_t vers)
 234 {
 235   struct svc_callout *prev;
 236   register struct svc_callout *s;
 237
 238   if ((s = svc_find (prog, vers, &prev)) == NULL_SVC)
 239     return;
 240   bool is_mapped = s->sc_mapped;
 241
 242   if (prev == NULL_SVC)
 243     svc_head = s->sc_next;
 244   else
 245     prev->sc_next = s->sc_next;
 246
 247   s->sc_next = NULL_SVC;
 248   mem_free ((char *) s, (u_int) sizeof (struct svc_callout));
 249   /* now unregister the information with the local binder service */
 250   if (is_mapped)
 251     pmap_unset (prog, vers);
 252 }
 253 libc_hidden_nolink_sunrpc (svc_unregister, GLIBC_2_0)
 254
 255 /* ******************* REPLY GENERATION ROUTINES  ************ */
 256
 257 /* Send a reply to an rpc request */
 258 bool_t
 259 svc_sendreply (register SVCXPRT *xprt, xdrproc_t xdr_results,
 260                caddr_t xdr_location)
 261 {
 262   struct rpc_msg rply;
 263
 264   rply.rm_direction = REPLY;
 265   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 266   rply.acpted_rply.ar_verf = xprt->xp_verf;
 267   rply.acpted_rply.ar_stat = SUCCESS;
 268   rply.acpted_rply.ar_results.where = xdr_location;
 269   rply.acpted_rply.ar_results.proc = xdr_results;
 270   return SVC_REPLY (xprt, &rply);
 271 }
 272 #ifdef EXPORT_RPC_SYMBOLS
 273 libc_hidden_def (svc_sendreply)
 274 #else
 275 libc_hidden_nolink_sunrpc (svc_sendreply, GLIBC_2_0)
 276 #endif
 277
 278 /* No procedure error reply */
 279 void
 280 svcerr_noproc (register SVCXPRT *xprt)
 281 {
 282   struct rpc_msg rply;
 283
 284   rply.rm_direction = REPLY;
 285   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 286   rply.acpted_rply.ar_verf = xprt->xp_verf;
 287   rply.acpted_rply.ar_stat = PROC_UNAVAIL;
 288   SVC_REPLY (xprt, &rply);
 289 }
 290 #ifdef EXPORT_RPC_SYMBOLS
 291 libc_hidden_def (svcerr_noproc)
 292 #else
 293 libc_hidden_nolink_sunrpc (svcerr_noproc, GLIBC_2_0)
 294 #endif
 295
 296 /* Can't decode args error reply */
 297 void
 298 svcerr_decode (register SVCXPRT *xprt)
 299 {
 300   struct rpc_msg rply;
 301
 302   rply.rm_direction = REPLY;
 303   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 304   rply.acpted_rply.ar_verf = xprt->xp_verf;
 305   rply.acpted_rply.ar_stat = GARBAGE_ARGS;
 306   SVC_REPLY (xprt, &rply);
 307 }
 308 #ifdef EXPORT_RPC_SYMBOLS
 309 libc_hidden_def (svcerr_decode)
 310 #else
 311 libc_hidden_nolink_sunrpc (svcerr_decode, GLIBC_2_0)
 312 #endif
 313
 314 /* Some system error */
 315 void
 316 svcerr_systemerr (register SVCXPRT *xprt)
 317 {
 318   struct rpc_msg rply;
 319
 320   rply.rm_direction = REPLY;
 321   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 322   rply.acpted_rply.ar_verf = xprt->xp_verf;
 323   rply.acpted_rply.ar_stat = SYSTEM_ERR;
 324   SVC_REPLY (xprt, &rply);
 325 }
 326 #ifdef EXPORT_RPC_SYMBOLS
 327 libc_hidden_def (svcerr_systemerr)
 328 #else
 329 libc_hidden_nolink_sunrpc (svcerr_systemerr, GLIBC_2_0)
 330 #endif
 331
 332 /* Authentication error reply */
 333 void
 334 svcerr_auth (SVCXPRT *xprt, enum auth_stat why)
 335 {
 336   struct rpc_msg rply;
 337
 338   rply.rm_direction = REPLY;
 339   rply.rm_reply.rp_stat = MSG_DENIED;
 340   rply.rjcted_rply.rj_stat = AUTH_ERROR;
 341   rply.rjcted_rply.rj_why = why;
 342   SVC_REPLY (xprt, &rply);
 343 }
 344 libc_hidden_nolink_sunrpc (svcerr_auth, GLIBC_2_0)
 345
 346 /* Auth too weak error reply */
 347 void
 348 svcerr_weakauth (SVCXPRT *xprt)
 349 {
 350   svcerr_auth (xprt, AUTH_TOOWEAK);
 351 }
 352 libc_hidden_nolink_sunrpc (svcerr_weakauth, GLIBC_2_0)
 353
 354 /* Program unavailable error reply */
 355 void
 356 svcerr_noprog (register SVCXPRT *xprt)
 357 {
 358   struct rpc_msg rply;
 359
 360   rply.rm_direction = REPLY;
 361   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 362   rply.acpted_rply.ar_verf = xprt->xp_verf;
 363   rply.acpted_rply.ar_stat = PROG_UNAVAIL;
 364   SVC_REPLY (xprt, &rply);
 365 }
 366 libc_hidden_nolink_sunrpc (svcerr_noprog, GLIBC_2_0)
 367
 368 /* Program version mismatch error reply */
 369 void
 370 svcerr_progvers (register SVCXPRT *xprt, rpcvers_t low_vers,
 371                  rpcvers_t high_vers)
 372 {
 373   struct rpc_msg rply;
 374
 375   rply.rm_direction = REPLY;
 376   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 377   rply.acpted_rply.ar_verf = xprt->xp_verf;
 378   rply.acpted_rply.ar_stat = PROG_MISMATCH;
 379   rply.acpted_rply.ar_vers.low = low_vers;
 380   rply.acpted_rply.ar_vers.high = high_vers;
 381   SVC_REPLY (xprt, &rply);
 382 }
 383 libc_hidden_nolink_sunrpc (svcerr_progvers, GLIBC_2_0)
 384
 385 /* ******************* SERVER INPUT STUFF ******************* */
 386
 387 /*
 388  * Get server side input from some transport.
 389  *
 390  * Statement of authentication parameters management:
 391  * This function owns and manages all authentication parameters, specifically
 392  * the "raw" parameters (msg.rm_call.cb_cred and msg.rm_call.cb_verf) and
 393  * the "cooked" credentials (rqst->rq_clntcred).
 394  * However, this function does not know the structure of the cooked
 395  * credentials, so it make the following assumptions:
 396  *   a) the structure is contiguous (no pointers), and
 397  *   b) the cred structure size does not exceed RQCRED_SIZE bytes.
 398  * In all events, all three parameters are freed upon exit from this routine.
 399  * The storage is trivially management on the call stack in user land, but
 400  * is mallocated in kernel land.
 401  */
 402
 403 void
 404 svc_getreq (int rdfds)
 405 {
 406   fd_set readfds;
 407
 408   FD_ZERO (&readfds);
 409   readfds.fds_bits[0] = rdfds;
 410   svc_getreqset (&readfds);
 411 }
 412 libc_hidden_nolink_sunrpc (svc_getreq, GLIBC_2_0)
 413
 414 void
 415 svc_getreqset (fd_set *readfds)
 416 {
 417   register fd_mask mask;
 418   register fd_mask *maskp;
 419   register int setsize;
 420   register int sock;
 421   register int bit;
 422
 423   setsize = _rpc_dtablesize ();
 424   if (setsize > FD_SETSIZE)
 425     setsize = FD_SETSIZE;
 426   maskp = readfds->fds_bits;
 427   for (sock = 0; sock < setsize; sock += NFDBITS)
 428     for (mask = *maskp++; (bit = ffsl (mask)); mask ^= (1L << (bit - 1)))
 429       svc_getreq_common (sock + bit - 1);
 430 }
 431 libc_hidden_nolink_sunrpc (svc_getreqset, GLIBC_2_0)
 432
 433 void
 434 svc_getreq_poll (struct pollfd *pfdp, int pollretval)
 435 {
 436   if (pollretval == 0)
 437     return;
 438
 439   register int fds_found;
 440   for (int i = fds_found = 0; i < svc_max_pollfd; ++i)
 441     {
 442       register struct pollfd *p = &pfdp[i];
 443
 444       if (p->fd != -1 && p->revents)
 445         {
 446           /* fd has input waiting */
 447           if (p->revents & POLLNVAL)
 448             xprt_unregister (xports[p->fd]);
 449           else
 450             svc_getreq_common (p->fd);
 451
 452           if (++fds_found >= pollretval)
 453             break;
 454         }
 455     }
 456 }
 457 #ifdef EXPORT_RPC_SYMBOLS
 458 libc_hidden_def (svc_getreq_poll)
 459 #else
 460 libc_hidden_nolink_sunrpc (svc_getreq_poll, GLIBC_2_2)
 461 #endif
 462
 463
 464 void
 465 svc_getreq_common (const int fd)
 466 {
 467   enum xprt_stat stat;
 468   struct rpc_msg msg;
 469   register SVCXPRT *xprt;
 470   char cred_area[2 * MAX_AUTH_BYTES + RQCRED_SIZE];
 471   msg.rm_call.cb_cred.oa_base = cred_area;
 472   msg.rm_call.cb_verf.oa_base = &(cred_area[MAX_AUTH_BYTES]);
 473
 474   xprt = xports[fd];
 475   /* Do we control fd? */
 476   if (xprt == NULL)
 477      return;
 478
 479   /* now receive msgs from xprtprt (support batch calls) */
 480   do
 481     {
 482       if (SVC_RECV (xprt, &msg))
 483         {
 484           /* now find the exported program and call it */
 485           struct svc_callout *s;
 486           struct svc_req r;
 487           enum auth_stat why;
 488           rpcvers_t low_vers;
 489           rpcvers_t high_vers;
 490           int prog_found;
 491
 492           r.rq_clntcred = &(cred_area[2 * MAX_AUTH_BYTES]);
 493           r.rq_xprt = xprt;
 494           r.rq_prog = msg.rm_call.cb_prog;
 495           r.rq_vers = msg.rm_call.cb_vers;
 496           r.rq_proc = msg.rm_call.cb_proc;
 497           r.rq_cred = msg.rm_call.cb_cred;
 498
 499           /* first authenticate the message */
 500           /* Check for null flavor and bypass these calls if possible */
 501
 502           if (msg.rm_call.cb_cred.oa_flavor == AUTH_NULL)
 503             {
 504               r.rq_xprt->xp_verf.oa_flavor = _null_auth.oa_flavor;
 505               r.rq_xprt->xp_verf.oa_length = 0;
 506             }
 507           else if ((why = _authenticate (&r, &msg)) != AUTH_OK)
 508             {
 509               svcerr_auth (xprt, why);
 510               goto call_done;
 511             }
 512
 513           /* now match message with a registered service */
 514           prog_found = FALSE;
 515           low_vers = 0 - 1;
 516           high_vers = 0;
 517
 518           for (s = svc_head; s != NULL_SVC; s = s->sc_next)
 519             {
 520               if (s->sc_prog == r.rq_prog)
 521                 {
 522                   if (s->sc_vers == r.rq_vers)
 523                     {
 524                       (*s->sc_dispatch) (&r, xprt);
 525                       goto call_done;
 526                     }
 527                   /* found correct version */
 528                   prog_found = TRUE;
 529                   if (s->sc_vers < low_vers)
 530                     low_vers = s->sc_vers;
 531                   if (s->sc_vers > high_vers)
 532                     high_vers = s->sc_vers;
 533                 }
 534               /* found correct program */
 535             }
 536           /* if we got here, the program or version
 537              is not served ... */
 538           if (prog_found)
 539             svcerr_progvers (xprt, low_vers, high_vers);
 540           else
 541             svcerr_noprog (xprt);
 542           /* Fall through to ... */
 543         }
 544     call_done:
 545       if ((stat = SVC_STAT (xprt)) == XPRT_DIED)
 546         {
 547           SVC_DESTROY (xprt);
 548           break;
 549         }
 550     }
 551   while (stat == XPRT_MOREREQS);
 552 }
 553 libc_hidden_nolink_sunrpc (svc_getreq_common, GLIBC_2_2)
 554
 555 /* If there are no file descriptors available, then accept will fail.
 556    We want to delay here so the connection request can be dequeued;
 557    otherwise we can bounce between polling and accepting, never giving the
 558    request a chance to dequeue and eating an enormous amount of cpu time
 559    in svc_run if we're polling on many file descriptors.  */
 560 void
 561 __svc_accept_failed (void)
 562 {
 563   if (errno == EMFILE)
 564     {
 565       struct timespec ts = { .tv_sec = 0, .tv_nsec = 50000000 };
 566       __nanosleep (&ts, NULL);
 567     }
 568 }
 569
 570 #ifdef _RPC_THREAD_SAFE_
 571
 572 void
 573 __rpc_thread_svc_cleanup (void)
 574 {
 575   struct svc_callout *svcp;
 576
 577   while ((svcp = svc_head) != NULL)
 578     svc_unregister (svcp->sc_prog, svcp->sc_vers);
 579 }
 580
 581 #endif /* _RPC_THREAD_SAFE_ */