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) 2002-2023 Free Software Foundation, Inc.
   8  *  This file is part of the GNU C Library.
   9  *
  10  *  The GNU C Library is free software; you can redistribute it and/or
  11  *  modify it under the terms of the GNU Lesser General Public
  12  *  License as published by the Free Software Foundation; either
  13  *  version 2.1 of the License, or (at your option) any later version.
  14  *
  15  *  The GNU C Library is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  *  Lesser General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU Lesser General Public
  21  *  License along with the GNU C Library; if not, see
  22  *  <https://www.gnu.org/licenses/>.
  23  *
  24  * Copyright (c) 2010, Oracle America, Inc.
  25  *
  26  * Redistribution and use in source and binary forms, with or without
  27  * modification, are permitted provided that the following conditions are
  28  * met:
  29  *
  30  *     * Redistributions of source code must retain the above copyright
  31  *       notice, this list of conditions and the following disclaimer.
  32  *     * Redistributions in binary form must reproduce the above
  33  *       copyright notice, this list of conditions and the following
  34  *       disclaimer in the documentation and/or other materials
  35  *       provided with the distribution.
  36  *     * Neither the name of the "Oracle America, Inc." nor the names of its
  37  *       contributors may be used to endorse or promote products derived
  38  *       from this software without specific prior written permission.
  39  *
  40  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  41  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  42  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  43  *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  44  *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
  45  *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  47  *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  48  *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  49  *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  50  *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  51  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  52  */
  53
  54 #include <errno.h>
  55 #include <unistd.h>
  56 #include <rpc/rpc.h>
  57 #include <rpc/svc.h>
  58 #include <rpc/pmap_clnt.h>
  59 #include <sys/poll.h>
  60 #include <time.h>
  61 #include <shlib-compat.h>
  62
  63 #define xports RPC_THREAD_VARIABLE(svc_xports_s)
  64
  65 #define NULL_SVC ((struct svc_callout *)0)
  66 #define RQCRED_SIZE     400     /* this size is excessive */
  67
  68 /* The services list
  69    Each entry represents a set of procedures (an rpc program).
  70    The dispatch routine takes request structs and runs the
  71    appropriate procedure. */
  72 struct svc_callout {
  73   struct svc_callout *sc_next;
  74   rpcprog_t sc_prog;
  75   rpcvers_t sc_vers;
  76   void (*sc_dispatch) (struct svc_req *, SVCXPRT *);
  77   bool_t sc_mapped;
  78 };
  79 #define svc_head RPC_THREAD_VARIABLE(svc_head_s)
  80
  81 /* ***************  SVCXPRT related stuff **************** */
  82
  83 /* Activate a transport handle. */
  84 void
  85 xprt_register (SVCXPRT *xprt)
  86 {
  87   register int sock = xprt->xp_sock;
  88   register int i;
  89
  90   if (xports == NULL)
  91     {
  92       xports = (SVCXPRT **) calloc (_rpc_dtablesize (), sizeof (SVCXPRT *));
  93       if (xports == NULL) /* Don't add handle */
  94         return;
  95     }
  96
  97   if (sock < _rpc_dtablesize ())
  98     {
  99       struct pollfd *new_svc_pollfd;
 100
 101       xports[sock] = xprt;
 102       if (sock < FD_SETSIZE)
 103         FD_SET (sock, &svc_fdset);
 104
 105       /* Check if we have an empty slot */
 106       for (i = 0; i < svc_max_pollfd; ++i)
 107         if (svc_pollfd[i].fd == -1)
 108           {
 109             svc_pollfd[i].fd = sock;
 110             svc_pollfd[i].events = (POLLIN | POLLPRI |
 111                                     POLLRDNORM | POLLRDBAND);
 112             return;
 113           }
 114
 115       new_svc_pollfd = (struct pollfd *) realloc (svc_pollfd,
 116                                                   sizeof (struct pollfd)
 117                                                   * (svc_max_pollfd + 1));
 118       if (new_svc_pollfd == NULL) /* Out of memory */
 119         return;
 120       svc_pollfd = new_svc_pollfd;
 121       ++svc_max_pollfd;
 122
 123       svc_pollfd[svc_max_pollfd - 1].fd = sock;
 124       svc_pollfd[svc_max_pollfd - 1].events = (POLLIN | POLLPRI |
 125                                                POLLRDNORM | POLLRDBAND);
 126     }
 127 }
 128 libc_hidden_nolink_sunrpc (xprt_register, GLIBC_2_0)
 129
 130 /* De-activate a transport handle. */
 131 void
 132 xprt_unregister (SVCXPRT *xprt)
 133 {
 134   register int sock = xprt->xp_sock;
 135   register int i;
 136
 137   if ((sock < _rpc_dtablesize ()) && (xports[sock] == xprt))
 138     {
 139       xports[sock] = (SVCXPRT *) 0;
 140
 141       if (sock < FD_SETSIZE)
 142         FD_CLR (sock, &svc_fdset);
 143
 144       for (i = 0; i < svc_max_pollfd; ++i)
 145         if (svc_pollfd[i].fd == sock)
 146           svc_pollfd[i].fd = -1;
 147     }
 148 }
 149 #ifdef EXPORT_RPC_SYMBOLS
 150 libc_hidden_def (xprt_unregister)
 151 #else
 152 libc_hidden_nolink_sunrpc (xprt_unregister, GLIBC_2_0)
 153 #endif
 154
 155
 156 /* ********************** CALLOUT list related stuff ************* */
 157
 158 /* Search the callout list for a program number, return the callout
 159    struct. */
 160 static struct svc_callout *
 161 svc_find (rpcprog_t prog, rpcvers_t vers, struct svc_callout **prev)
 162 {
 163   register struct svc_callout *s, *p;
 164
 165   p = NULL_SVC;
 166   for (s = svc_head; s != NULL_SVC; s = s->sc_next)
 167     {
 168       if ((s->sc_prog == prog) && (s->sc_vers == vers))
 169         goto done;
 170       p = s;
 171     }
 172 done:
 173   *prev = p;
 174   return s;
 175 }
 176
 177 /* Add a service program to the callout list.
 178    The dispatch routine will be called when a rpc request for this
 179    program number comes in. */
 180 bool_t
 181 svc_register (SVCXPRT * xprt, rpcprog_t prog, rpcvers_t vers,
 182               void (*dispatch) (struct svc_req *, SVCXPRT *),
 183               rpcproc_t protocol)
 184 {
 185   struct svc_callout *prev;
 186   register struct svc_callout *s;
 187
 188   if ((s = svc_find (prog, vers, &prev)) != NULL_SVC)
 189     {
 190       if (s->sc_dispatch == dispatch)
 191         goto pmap_it;           /* he is registering another xptr */
 192       return FALSE;
 193     }
 194   s = (struct svc_callout *) mem_alloc (sizeof (struct svc_callout));
 195   if (s == (struct svc_callout *) 0)
 196     return FALSE;
 197
 198   s->sc_prog = prog;
 199   s->sc_vers = vers;
 200   s->sc_dispatch = dispatch;
 201   s->sc_next = svc_head;
 202   s->sc_mapped = FALSE;
 203   svc_head = s;
 204
 205 pmap_it:
 206   /* now register the information with the local binder service */
 207   if (protocol)
 208     {
 209       if (! pmap_set (prog, vers, protocol, xprt->xp_port))
 210         return FALSE;
 211
 212       s->sc_mapped = TRUE;
 213     }
 214
 215   return TRUE;
 216 }
 217 #ifdef EXPORT_RPC_SYMBOLS
 218 libc_hidden_def (svc_register)
 219 #else
 220 libc_hidden_nolink_sunrpc (svc_register, GLIBC_2_0)
 221 #endif
 222
 223 /* Remove a service program from the callout list. */
 224 void
 225 svc_unregister (rpcprog_t prog, rpcvers_t vers)
 226 {
 227   struct svc_callout *prev;
 228   register struct svc_callout *s;
 229
 230   if ((s = svc_find (prog, vers, &prev)) == NULL_SVC)
 231     return;
 232   bool is_mapped = s->sc_mapped;
 233
 234   if (prev == NULL_SVC)
 235     svc_head = s->sc_next;
 236   else
 237     prev->sc_next = s->sc_next;
 238
 239   s->sc_next = NULL_SVC;
 240   mem_free ((char *) s, (u_int) sizeof (struct svc_callout));
 241   /* now unregister the information with the local binder service */
 242   if (is_mapped)
 243     pmap_unset (prog, vers);
 244 }
 245 libc_hidden_nolink_sunrpc (svc_unregister, GLIBC_2_0)
 246
 247 /* ******************* REPLY GENERATION ROUTINES  ************ */
 248
 249 /* Send a reply to an rpc request */
 250 bool_t
 251 svc_sendreply (register SVCXPRT *xprt, xdrproc_t xdr_results,
 252                caddr_t xdr_location)
 253 {
 254   struct rpc_msg rply;
 255
 256   rply.rm_direction = REPLY;
 257   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 258   rply.acpted_rply.ar_verf = xprt->xp_verf;
 259   rply.acpted_rply.ar_stat = SUCCESS;
 260   rply.acpted_rply.ar_results.where = xdr_location;
 261   rply.acpted_rply.ar_results.proc = xdr_results;
 262   return SVC_REPLY (xprt, &rply);
 263 }
 264 #ifdef EXPORT_RPC_SYMBOLS
 265 libc_hidden_def (svc_sendreply)
 266 #else
 267 libc_hidden_nolink_sunrpc (svc_sendreply, GLIBC_2_0)
 268 #endif
 269
 270 /* No procedure error reply */
 271 void
 272 svcerr_noproc (register SVCXPRT *xprt)
 273 {
 274   struct rpc_msg rply;
 275
 276   rply.rm_direction = REPLY;
 277   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 278   rply.acpted_rply.ar_verf = xprt->xp_verf;
 279   rply.acpted_rply.ar_stat = PROC_UNAVAIL;
 280   SVC_REPLY (xprt, &rply);
 281 }
 282 #ifdef EXPORT_RPC_SYMBOLS
 283 libc_hidden_def (svcerr_noproc)
 284 #else
 285 libc_hidden_nolink_sunrpc (svcerr_noproc, GLIBC_2_0)
 286 #endif
 287
 288 /* Can't decode args error reply */
 289 void
 290 svcerr_decode (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 = GARBAGE_ARGS;
 298   SVC_REPLY (xprt, &rply);
 299 }
 300 #ifdef EXPORT_RPC_SYMBOLS
 301 libc_hidden_def (svcerr_decode)
 302 #else
 303 libc_hidden_nolink_sunrpc (svcerr_decode, GLIBC_2_0)
 304 #endif
 305
 306 /* Some system error */
 307 void
 308 svcerr_systemerr (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 = SYSTEM_ERR;
 316   SVC_REPLY (xprt, &rply);
 317 }
 318 #ifdef EXPORT_RPC_SYMBOLS
 319 libc_hidden_def (svcerr_systemerr)
 320 #else
 321 libc_hidden_nolink_sunrpc (svcerr_systemerr, GLIBC_2_0)
 322 #endif
 323
 324 /* Authentication error reply */
 325 void
 326 svcerr_auth (SVCXPRT *xprt, enum auth_stat why)
 327 {
 328   struct rpc_msg rply;
 329
 330   rply.rm_direction = REPLY;
 331   rply.rm_reply.rp_stat = MSG_DENIED;
 332   rply.rjcted_rply.rj_stat = AUTH_ERROR;
 333   rply.rjcted_rply.rj_why = why;
 334   SVC_REPLY (xprt, &rply);
 335 }
 336 libc_hidden_nolink_sunrpc (svcerr_auth, GLIBC_2_0)
 337
 338 /* Auth too weak error reply */
 339 void
 340 svcerr_weakauth (SVCXPRT *xprt)
 341 {
 342   svcerr_auth (xprt, AUTH_TOOWEAK);
 343 }
 344 libc_hidden_nolink_sunrpc (svcerr_weakauth, GLIBC_2_0)
 345
 346 /* Program unavailable error reply */
 347 void
 348 svcerr_noprog (register SVCXPRT *xprt)
 349 {
 350   struct rpc_msg rply;
 351
 352   rply.rm_direction = REPLY;
 353   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 354   rply.acpted_rply.ar_verf = xprt->xp_verf;
 355   rply.acpted_rply.ar_stat = PROG_UNAVAIL;
 356   SVC_REPLY (xprt, &rply);
 357 }
 358 libc_hidden_nolink_sunrpc (svcerr_noprog, GLIBC_2_0)
 359
 360 /* Program version mismatch error reply */
 361 void
 362 svcerr_progvers (register SVCXPRT *xprt, rpcvers_t low_vers,
 363                  rpcvers_t high_vers)
 364 {
 365   struct rpc_msg rply;
 366
 367   rply.rm_direction = REPLY;
 368   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 369   rply.acpted_rply.ar_verf = xprt->xp_verf;
 370   rply.acpted_rply.ar_stat = PROG_MISMATCH;
 371   rply.acpted_rply.ar_vers.low = low_vers;
 372   rply.acpted_rply.ar_vers.high = high_vers;
 373   SVC_REPLY (xprt, &rply);
 374 }
 375 libc_hidden_nolink_sunrpc (svcerr_progvers, GLIBC_2_0)
 376
 377 /* ******************* SERVER INPUT STUFF ******************* */
 378
 379 /*
 380  * Get server side input from some transport.
 381  *
 382  * Statement of authentication parameters management:
 383  * This function owns and manages all authentication parameters, specifically
 384  * the "raw" parameters (msg.rm_call.cb_cred and msg.rm_call.cb_verf) and
 385  * the "cooked" credentials (rqst->rq_clntcred).
 386  * However, this function does not know the structure of the cooked
 387  * credentials, so it make the following assumptions:
 388  *   a) the structure is contiguous (no pointers), and
 389  *   b) the cred structure size does not exceed RQCRED_SIZE bytes.
 390  * In all events, all three parameters are freed upon exit from this routine.
 391  * The storage is trivially management on the call stack in user land, but
 392  * is mallocated in kernel land.
 393  */
 394
 395 void
 396 svc_getreq (int rdfds)
 397 {
 398   fd_set readfds;
 399
 400   FD_ZERO (&readfds);
 401   readfds.fds_bits[0] = rdfds;
 402   svc_getreqset (&readfds);
 403 }
 404 libc_hidden_nolink_sunrpc (svc_getreq, GLIBC_2_0)
 405
 406 void
 407 svc_getreqset (fd_set *readfds)
 408 {
 409   register fd_mask mask;
 410   register fd_mask *maskp;
 411   register int setsize;
 412   register int sock;
 413   register int bit;
 414
 415   setsize = _rpc_dtablesize ();
 416   if (setsize > FD_SETSIZE)
 417     setsize = FD_SETSIZE;
 418   maskp = readfds->fds_bits;
 419   for (sock = 0; sock < setsize; sock += NFDBITS)
 420     for (mask = *maskp++; (bit = ffsl (mask)); mask ^= (1L << (bit - 1)))
 421       svc_getreq_common (sock + bit - 1);
 422 }
 423 libc_hidden_nolink_sunrpc (svc_getreqset, GLIBC_2_0)
 424
 425 void
 426 svc_getreq_poll (struct pollfd *pfdp, int pollretval)
 427 {
 428   if (pollretval == 0)
 429     return;
 430
 431   register int fds_found;
 432   for (int i = fds_found = 0; i < svc_max_pollfd; ++i)
 433     {
 434       register struct pollfd *p = &pfdp[i];
 435
 436       if (p->fd != -1 && p->revents)
 437         {
 438           /* fd has input waiting */
 439           if (p->revents & POLLNVAL)
 440             xprt_unregister (xports[p->fd]);
 441           else
 442             svc_getreq_common (p->fd);
 443
 444           if (++fds_found >= pollretval)
 445             break;
 446         }
 447     }
 448 }
 449 #ifdef EXPORT_RPC_SYMBOLS
 450 libc_hidden_def (svc_getreq_poll)
 451 #else
 452 libc_hidden_nolink_sunrpc (svc_getreq_poll, GLIBC_2_2)
 453 #endif
 454
 455
 456 void
 457 svc_getreq_common (const int fd)
 458 {
 459   enum xprt_stat stat;
 460   struct rpc_msg msg;
 461   register SVCXPRT *xprt;
 462   char cred_area[2 * MAX_AUTH_BYTES + RQCRED_SIZE];
 463   msg.rm_call.cb_cred.oa_base = cred_area;
 464   msg.rm_call.cb_verf.oa_base = &(cred_area[MAX_AUTH_BYTES]);
 465
 466   xprt = xports[fd];
 467   /* Do we control fd? */
 468   if (xprt == NULL)
 469      return;
 470
 471   /* now receive msgs from xprtprt (support batch calls) */
 472   do
 473     {
 474       if (SVC_RECV (xprt, &msg))
 475         {
 476           /* now find the exported program and call it */
 477           struct svc_callout *s;
 478           struct svc_req r;
 479           enum auth_stat why;
 480           rpcvers_t low_vers;
 481           rpcvers_t high_vers;
 482           int prog_found;
 483
 484           r.rq_clntcred = &(cred_area[2 * MAX_AUTH_BYTES]);
 485           r.rq_xprt = xprt;
 486           r.rq_prog = msg.rm_call.cb_prog;
 487           r.rq_vers = msg.rm_call.cb_vers;
 488           r.rq_proc = msg.rm_call.cb_proc;
 489           r.rq_cred = msg.rm_call.cb_cred;
 490
 491           /* first authenticate the message */
 492           /* Check for null flavor and bypass these calls if possible */
 493
 494           if (msg.rm_call.cb_cred.oa_flavor == AUTH_NULL)
 495             {
 496               r.rq_xprt->xp_verf.oa_flavor = _null_auth.oa_flavor;
 497               r.rq_xprt->xp_verf.oa_length = 0;
 498             }
 499           else if ((why = _authenticate (&r, &msg)) != AUTH_OK)
 500             {
 501               svcerr_auth (xprt, why);
 502               goto call_done;
 503             }
 504
 505           /* now match message with a registered service */
 506           prog_found = FALSE;
 507           low_vers = 0 - 1;
 508           high_vers = 0;
 509
 510           for (s = svc_head; s != NULL_SVC; s = s->sc_next)
 511             {
 512               if (s->sc_prog == r.rq_prog)
 513                 {
 514                   if (s->sc_vers == r.rq_vers)
 515                     {
 516                       (*s->sc_dispatch) (&r, xprt);
 517                       goto call_done;
 518                     }
 519                   /* found correct version */
 520                   prog_found = TRUE;
 521                   if (s->sc_vers < low_vers)
 522                     low_vers = s->sc_vers;
 523                   if (s->sc_vers > high_vers)
 524                     high_vers = s->sc_vers;
 525                 }
 526               /* found correct program */
 527             }
 528           /* if we got here, the program or version
 529              is not served ... */
 530           if (prog_found)
 531             svcerr_progvers (xprt, low_vers, high_vers);
 532           else
 533             svcerr_noprog (xprt);
 534           /* Fall through to ... */
 535         }
 536     call_done:
 537       if ((stat = SVC_STAT (xprt)) == XPRT_DIED)
 538         {
 539           SVC_DESTROY (xprt);
 540           break;
 541         }
 542     }
 543   while (stat == XPRT_MOREREQS);
 544 }
 545 libc_hidden_nolink_sunrpc (svc_getreq_common, GLIBC_2_2)
 546
 547 void
 548 __svc_wait_on_error (void)
 549 {
 550   struct timespec ts = { .tv_sec = 0, .tv_nsec = 50000000 };
 551   __nanosleep (&ts, NULL);
 552 }
 553
 554 /* If there are no file descriptors available, then accept will fail.
 555    We want to delay here so the connection request can be dequeued;
 556    otherwise we can bounce between polling and accepting, never giving the
 557    request a chance to dequeue and eating an enormous amount of cpu time
 558    in svc_run if we're polling on many file descriptors.  */
 559 void
 560 __svc_accept_failed (void)
 561 {
 562   if (errno == EMFILE)
 563     {
 564       __svc_wait_on_error ();
 565     }
 566 }
 567
 568
 569 void
 570 __rpc_thread_svc_cleanup (void)
 571 {
 572   struct svc_callout *svcp;
 573
 574   while ((svcp = svc_head) != NULL)
 575     svc_unregister (svcp->sc_prog, svcp->sc_vers);
 576 }