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 #include <shlib-compat.h>
  63
  64 #ifdef _RPC_THREAD_SAFE_
  65 #define xports RPC_THREAD_VARIABLE(svc_xports_s)
  66 #else
  67 static SVCXPRT **xports;
  68 #endif
  69
  70 #define NULL_SVC ((struct svc_callout *)0)
  71 #define RQCRED_SIZE     400     /* this size is excessive */
  72
  73 /* The services list
  74    Each entry represents a set of procedures (an rpc program).
  75    The dispatch routine takes request structs and runs the
  76    appropriate procedure. */
  77 struct svc_callout {
  78   struct svc_callout *sc_next;
  79   rpcprog_t sc_prog;
  80   rpcvers_t sc_vers;
  81   void (*sc_dispatch) (struct svc_req *, SVCXPRT *);
  82   bool_t sc_mapped;
  83 };
  84 #ifdef _RPC_THREAD_SAFE_
  85 #define svc_head RPC_THREAD_VARIABLE(svc_head_s)
  86 #else
  87 static struct svc_callout *svc_head;
  88 #endif
  89
  90 /* ***************  SVCXPRT related stuff **************** */
  91
  92 /* Activate a transport handle. */
  93 void
  94 xprt_register (SVCXPRT *xprt)
  95 {
  96   register int sock = xprt->xp_sock;
  97   register int i;
  98
  99   if (xports == NULL)
 100     {
 101       xports = (SVCXPRT **) calloc (_rpc_dtablesize (), sizeof (SVCXPRT *));
 102       if (xports == NULL) /* Don't add handle */
 103         return;
 104     }
 105
 106   if (sock < _rpc_dtablesize ())
 107     {
 108       struct pollfd *new_svc_pollfd;
 109
 110       xports[sock] = xprt;
 111       if (sock < FD_SETSIZE)
 112         FD_SET (sock, &svc_fdset);
 113
 114       /* Check if we have an empty slot */
 115       for (i = 0; i < svc_max_pollfd; ++i)
 116         if (svc_pollfd[i].fd == -1)
 117           {
 118             svc_pollfd[i].fd = sock;
 119             svc_pollfd[i].events = (POLLIN | POLLPRI |
 120                                     POLLRDNORM | POLLRDBAND);
 121             return;
 122           }
 123
 124       new_svc_pollfd = (struct pollfd *) realloc (svc_pollfd,
 125                                                   sizeof (struct pollfd)
 126                                                   * (svc_max_pollfd + 1));
 127       if (new_svc_pollfd == NULL) /* Out of memory */
 128         return;
 129       svc_pollfd = new_svc_pollfd;
 130       ++svc_max_pollfd;
 131
 132       svc_pollfd[svc_max_pollfd - 1].fd = sock;
 133       svc_pollfd[svc_max_pollfd - 1].events = (POLLIN | POLLPRI |
 134                                                POLLRDNORM | POLLRDBAND);
 135     }
 136 }
 137 libc_hidden_nolink_sunrpc (xprt_register, GLIBC_2_0)
 138
 139 /* De-activate a transport handle. */
 140 void
 141 xprt_unregister (SVCXPRT *xprt)
 142 {
 143   register int sock = xprt->xp_sock;
 144   register int i;
 145
 146   if ((sock < _rpc_dtablesize ()) && (xports[sock] == xprt))
 147     {
 148       xports[sock] = (SVCXPRT *) 0;
 149
 150       if (sock < FD_SETSIZE)
 151         FD_CLR (sock, &svc_fdset);
 152
 153       for (i = 0; i < svc_max_pollfd; ++i)
 154         if (svc_pollfd[i].fd == sock)
 155           svc_pollfd[i].fd = -1;
 156     }
 157 }
 158 #ifdef EXPORT_RPC_SYMBOLS
 159 libc_hidden_def (xprt_unregister)
 160 #else
 161 libc_hidden_nolink_sunrpc (xprt_unregister, GLIBC_2_0)
 162 #endif
 163
 164
 165 /* ********************** CALLOUT list related stuff ************* */
 166
 167 /* Search the callout list for a program number, return the callout
 168    struct. */
 169 static struct svc_callout *
 170 svc_find (rpcprog_t prog, rpcvers_t vers, struct svc_callout **prev)
 171 {
 172   register struct svc_callout *s, *p;
 173
 174   p = NULL_SVC;
 175   for (s = svc_head; s != NULL_SVC; s = s->sc_next)
 176     {
 177       if ((s->sc_prog == prog) && (s->sc_vers == vers))
 178         goto done;
 179       p = s;
 180     }
 181 done:
 182   *prev = p;
 183   return s;
 184 }
 185
 186 /* Add a service program to the callout list.
 187    The dispatch routine will be called when a rpc request for this
 188    program number comes in. */
 189 bool_t
 190 svc_register (SVCXPRT * xprt, rpcprog_t prog, rpcvers_t vers,
 191               void (*dispatch) (struct svc_req *, SVCXPRT *),
 192               rpcproc_t protocol)
 193 {
 194   struct svc_callout *prev;
 195   register struct svc_callout *s;
 196
 197   if ((s = svc_find (prog, vers, &prev)) != NULL_SVC)
 198     {
 199       if (s->sc_dispatch == dispatch)
 200         goto pmap_it;           /* he is registering another xptr */
 201       return FALSE;
 202     }
 203   s = (struct svc_callout *) mem_alloc (sizeof (struct svc_callout));
 204   if (s == (struct svc_callout *) 0)
 205     return FALSE;
 206
 207   s->sc_prog = prog;
 208   s->sc_vers = vers;
 209   s->sc_dispatch = dispatch;
 210   s->sc_next = svc_head;
 211   s->sc_mapped = FALSE;
 212   svc_head = s;
 213
 214 pmap_it:
 215   /* now register the information with the local binder service */
 216   if (protocol)
 217     {
 218       if (! pmap_set (prog, vers, protocol, xprt->xp_port))
 219         return FALSE;
 220
 221       s->sc_mapped = TRUE;
 222     }
 223
 224   return TRUE;
 225 }
 226 #ifdef EXPORT_RPC_SYMBOLS
 227 libc_hidden_def (svc_register)
 228 #else
 229 libc_hidden_nolink_sunrpc (svc_register, GLIBC_2_0)
 230 #endif
 231
 232 /* Remove a service program from the callout list. */
 233 void
 234 svc_unregister (rpcprog_t prog, rpcvers_t vers)
 235 {
 236   struct svc_callout *prev;
 237   register struct svc_callout *s;
 238
 239   if ((s = svc_find (prog, vers, &prev)) == NULL_SVC)
 240     return;
 241   bool is_mapped = s->sc_mapped;
 242
 243   if (prev == NULL_SVC)
 244     svc_head = s->sc_next;
 245   else
 246     prev->sc_next = s->sc_next;
 247
 248   s->sc_next = NULL_SVC;
 249   mem_free ((char *) s, (u_int) sizeof (struct svc_callout));
 250   /* now unregister the information with the local binder service */
 251   if (is_mapped)
 252     pmap_unset (prog, vers);
 253 }
 254 libc_hidden_nolink_sunrpc (svc_unregister, GLIBC_2_0)
 255
 256 /* ******************* REPLY GENERATION ROUTINES  ************ */
 257
 258 /* Send a reply to an rpc request */
 259 bool_t
 260 svc_sendreply (register SVCXPRT *xprt, xdrproc_t xdr_results,
 261                caddr_t xdr_location)
 262 {
 263   struct rpc_msg rply;
 264
 265   rply.rm_direction = REPLY;
 266   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 267   rply.acpted_rply.ar_verf = xprt->xp_verf;
 268   rply.acpted_rply.ar_stat = SUCCESS;
 269   rply.acpted_rply.ar_results.where = xdr_location;
 270   rply.acpted_rply.ar_results.proc = xdr_results;
 271   return SVC_REPLY (xprt, &rply);
 272 }
 273 #ifdef EXPORT_RPC_SYMBOLS
 274 libc_hidden_def (svc_sendreply)
 275 #else
 276 libc_hidden_nolink_sunrpc (svc_sendreply, GLIBC_2_0)
 277 #endif
 278
 279 /* No procedure error reply */
 280 void
 281 svcerr_noproc (register SVCXPRT *xprt)
 282 {
 283   struct rpc_msg rply;
 284
 285   rply.rm_direction = REPLY;
 286   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 287   rply.acpted_rply.ar_verf = xprt->xp_verf;
 288   rply.acpted_rply.ar_stat = PROC_UNAVAIL;
 289   SVC_REPLY (xprt, &rply);
 290 }
 291 #ifdef EXPORT_RPC_SYMBOLS
 292 libc_hidden_def (svcerr_noproc)
 293 #else
 294 libc_hidden_nolink_sunrpc (svcerr_noproc, GLIBC_2_0)
 295 #endif
 296
 297 /* Can't decode args error reply */
 298 void
 299 svcerr_decode (register SVCXPRT *xprt)
 300 {
 301   struct rpc_msg rply;
 302
 303   rply.rm_direction = REPLY;
 304   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 305   rply.acpted_rply.ar_verf = xprt->xp_verf;
 306   rply.acpted_rply.ar_stat = GARBAGE_ARGS;
 307   SVC_REPLY (xprt, &rply);
 308 }
 309 #ifdef EXPORT_RPC_SYMBOLS
 310 libc_hidden_def (svcerr_decode)
 311 #else
 312 libc_hidden_nolink_sunrpc (svcerr_decode, GLIBC_2_0)
 313 #endif
 314
 315 /* Some system error */
 316 void
 317 svcerr_systemerr (register SVCXPRT *xprt)
 318 {
 319   struct rpc_msg rply;
 320
 321   rply.rm_direction = REPLY;
 322   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 323   rply.acpted_rply.ar_verf = xprt->xp_verf;
 324   rply.acpted_rply.ar_stat = SYSTEM_ERR;
 325   SVC_REPLY (xprt, &rply);
 326 }
 327 #ifdef EXPORT_RPC_SYMBOLS
 328 libc_hidden_def (svcerr_systemerr)
 329 #else
 330 libc_hidden_nolink_sunrpc (svcerr_systemerr, GLIBC_2_0)
 331 #endif
 332
 333 /* Authentication error reply */
 334 void
 335 svcerr_auth (SVCXPRT *xprt, enum auth_stat why)
 336 {
 337   struct rpc_msg rply;
 338
 339   rply.rm_direction = REPLY;
 340   rply.rm_reply.rp_stat = MSG_DENIED;
 341   rply.rjcted_rply.rj_stat = AUTH_ERROR;
 342   rply.rjcted_rply.rj_why = why;
 343   SVC_REPLY (xprt, &rply);
 344 }
 345 libc_hidden_nolink_sunrpc (svcerr_auth, GLIBC_2_0)
 346
 347 /* Auth too weak error reply */
 348 void
 349 svcerr_weakauth (SVCXPRT *xprt)
 350 {
 351   svcerr_auth (xprt, AUTH_TOOWEAK);
 352 }
 353 libc_hidden_nolink_sunrpc (svcerr_weakauth, GLIBC_2_0)
 354
 355 /* Program unavailable error reply */
 356 void
 357 svcerr_noprog (register SVCXPRT *xprt)
 358 {
 359   struct rpc_msg rply;
 360
 361   rply.rm_direction = REPLY;
 362   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 363   rply.acpted_rply.ar_verf = xprt->xp_verf;
 364   rply.acpted_rply.ar_stat = PROG_UNAVAIL;
 365   SVC_REPLY (xprt, &rply);
 366 }
 367 libc_hidden_nolink_sunrpc (svcerr_noprog, GLIBC_2_0)
 368
 369 /* Program version mismatch error reply */
 370 void
 371 svcerr_progvers (register SVCXPRT *xprt, rpcvers_t low_vers,
 372                  rpcvers_t high_vers)
 373 {
 374   struct rpc_msg rply;
 375
 376   rply.rm_direction = REPLY;
 377   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 378   rply.acpted_rply.ar_verf = xprt->xp_verf;
 379   rply.acpted_rply.ar_stat = PROG_MISMATCH;
 380   rply.acpted_rply.ar_vers.low = low_vers;
 381   rply.acpted_rply.ar_vers.high = high_vers;
 382   SVC_REPLY (xprt, &rply);
 383 }
 384 libc_hidden_nolink_sunrpc (svcerr_progvers, GLIBC_2_0)
 385
 386 /* ******************* SERVER INPUT STUFF ******************* */
 387
 388 /*
 389  * Get server side input from some transport.
 390  *
 391  * Statement of authentication parameters management:
 392  * This function owns and manages all authentication parameters, specifically
 393  * the "raw" parameters (msg.rm_call.cb_cred and msg.rm_call.cb_verf) and
 394  * the "cooked" credentials (rqst->rq_clntcred).
 395  * However, this function does not know the structure of the cooked
 396  * credentials, so it make the following assumptions:
 397  *   a) the structure is contiguous (no pointers), and
 398  *   b) the cred structure size does not exceed RQCRED_SIZE bytes.
 399  * In all events, all three parameters are freed upon exit from this routine.
 400  * The storage is trivially management on the call stack in user land, but
 401  * is mallocated in kernel land.
 402  */
 403
 404 void
 405 svc_getreq (int rdfds)
 406 {
 407   fd_set readfds;
 408
 409   FD_ZERO (&readfds);
 410   readfds.fds_bits[0] = rdfds;
 411   svc_getreqset (&readfds);
 412 }
 413 libc_hidden_nolink_sunrpc (svc_getreq, GLIBC_2_0)
 414
 415 void
 416 svc_getreqset (fd_set *readfds)
 417 {
 418   register fd_mask mask;
 419   register fd_mask *maskp;
 420   register int setsize;
 421   register int sock;
 422   register int bit;
 423
 424   setsize = _rpc_dtablesize ();
 425   if (setsize > FD_SETSIZE)
 426     setsize = FD_SETSIZE;
 427   maskp = readfds->fds_bits;
 428   for (sock = 0; sock < setsize; sock += NFDBITS)
 429     for (mask = *maskp++; (bit = ffsl (mask)); mask ^= (1L << (bit - 1)))
 430       svc_getreq_common (sock + bit - 1);
 431 }
 432 libc_hidden_nolink_sunrpc (svc_getreqset, GLIBC_2_0)
 433
 434 void
 435 svc_getreq_poll (struct pollfd *pfdp, int pollretval)
 436 {
 437   if (pollretval == 0)
 438     return;
 439
 440   register int fds_found;
 441   for (int i = fds_found = 0; i < svc_max_pollfd; ++i)
 442     {
 443       register struct pollfd *p = &pfdp[i];
 444
 445       if (p->fd != -1 && p->revents)
 446         {
 447           /* fd has input waiting */
 448           if (p->revents & POLLNVAL)
 449             xprt_unregister (xports[p->fd]);
 450           else
 451             svc_getreq_common (p->fd);
 452
 453           if (++fds_found >= pollretval)
 454             break;
 455         }
 456     }
 457 }
 458 #ifdef EXPORT_RPC_SYMBOLS
 459 libc_hidden_def (svc_getreq_poll)
 460 #else
 461 libc_hidden_nolink_sunrpc (svc_getreq_poll, GLIBC_2_2)
 462 #endif
 463
 464
 465 void
 466 svc_getreq_common (const int fd)
 467 {
 468   enum xprt_stat stat;
 469   struct rpc_msg msg;
 470   register SVCXPRT *xprt;
 471   char cred_area[2 * MAX_AUTH_BYTES + RQCRED_SIZE];
 472   msg.rm_call.cb_cred.oa_base = cred_area;
 473   msg.rm_call.cb_verf.oa_base = &(cred_area[MAX_AUTH_BYTES]);
 474
 475   xprt = xports[fd];
 476   /* Do we control fd? */
 477   if (xprt == NULL)
 478      return;
 479
 480   /* now receive msgs from xprtprt (support batch calls) */
 481   do
 482     {
 483       if (SVC_RECV (xprt, &msg))
 484         {
 485           /* now find the exported program and call it */
 486           struct svc_callout *s;
 487           struct svc_req r;
 488           enum auth_stat why;
 489           rpcvers_t low_vers;
 490           rpcvers_t high_vers;
 491           int prog_found;
 492
 493           r.rq_clntcred = &(cred_area[2 * MAX_AUTH_BYTES]);
 494           r.rq_xprt = xprt;
 495           r.rq_prog = msg.rm_call.cb_prog;
 496           r.rq_vers = msg.rm_call.cb_vers;
 497           r.rq_proc = msg.rm_call.cb_proc;
 498           r.rq_cred = msg.rm_call.cb_cred;
 499
 500           /* first authenticate the message */
 501           /* Check for null flavor and bypass these calls if possible */
 502
 503           if (msg.rm_call.cb_cred.oa_flavor == AUTH_NULL)
 504             {
 505               r.rq_xprt->xp_verf.oa_flavor = _null_auth.oa_flavor;
 506               r.rq_xprt->xp_verf.oa_length = 0;
 507             }
 508           else if ((why = _authenticate (&r, &msg)) != AUTH_OK)
 509             {
 510               svcerr_auth (xprt, why);
 511               goto call_done;
 512             }
 513
 514           /* now match message with a registered service */
 515           prog_found = FALSE;
 516           low_vers = 0 - 1;
 517           high_vers = 0;
 518
 519           for (s = svc_head; s != NULL_SVC; s = s->sc_next)
 520             {
 521               if (s->sc_prog == r.rq_prog)
 522                 {
 523                   if (s->sc_vers == r.rq_vers)
 524                     {
 525                       (*s->sc_dispatch) (&r, xprt);
 526                       goto call_done;
 527                     }
 528                   /* found correct version */
 529                   prog_found = TRUE;
 530                   if (s->sc_vers < low_vers)
 531                     low_vers = s->sc_vers;
 532                   if (s->sc_vers > high_vers)
 533                     high_vers = s->sc_vers;
 534                 }
 535               /* found correct program */
 536             }
 537           /* if we got here, the program or version
 538              is not served ... */
 539           if (prog_found)
 540             svcerr_progvers (xprt, low_vers, high_vers);
 541           else
 542             svcerr_noprog (xprt);
 543           /* Fall through to ... */
 544         }
 545     call_done:
 546       if ((stat = SVC_STAT (xprt)) == XPRT_DIED)
 547         {
 548           SVC_DESTROY (xprt);
 549           break;
 550         }
 551     }
 552   while (stat == XPRT_MOREREQS);
 553 }
 554 libc_hidden_nolink_sunrpc (svc_getreq_common, GLIBC_2_2)
 555
 556 /* If there are no file descriptors available, then accept will fail.
 557    We want to delay here so the connection request can be dequeued;
 558    otherwise we can bounce between polling and accepting, never giving the
 559    request a chance to dequeue and eating an enormous amount of cpu time
 560    in svc_run if we're polling on many file descriptors.  */
 561 void
 562 __svc_accept_failed (void)
 563 {
 564   if (errno == EMFILE)
 565     {
 566       struct timespec ts = { .tv_sec = 0, .tv_nsec = 50000000 };
 567       __nanosleep (&ts, NULL);
 568     }
 569 }
 570
 571 #ifdef _RPC_THREAD_SAFE_
 572
 573 void
 574 __rpc_thread_svc_cleanup (void)
 575 {
 576   struct svc_callout *svcp;
 577
 578   while ((svcp = svc_head) != NULL)
 579     svc_unregister (svcp->sc_prog, svcp->sc_vers);
 580 }
 581
 582 #endif /* _RPC_THREAD_SAFE_ */