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) 2002-2019 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 #define xports RPC_THREAD_VARIABLE(svc_xports_s)
  65
  66 #define NULL_SVC ((struct svc_callout *)0)
  67 #define RQCRED_SIZE     400     /* this size is excessive */
  68
  69 /* The services list
  70    Each entry represents a set of procedures (an rpc program).
  71    The dispatch routine takes request structs and runs the
  72    appropriate procedure. */
  73 struct svc_callout {
  74   struct svc_callout *sc_next;
  75   rpcprog_t sc_prog;
  76   rpcvers_t sc_vers;
  77   void (*sc_dispatch) (struct svc_req *, SVCXPRT *);
  78   bool_t sc_mapped;
  79 };
  80 #define svc_head RPC_THREAD_VARIABLE(svc_head_s)
  81
  82 /* ***************  SVCXPRT related stuff **************** */
  83
  84 /* Activate a transport handle. */
  85 void
  86 xprt_register (SVCXPRT *xprt)
  87 {
  88   register int sock = xprt->xp_sock;
  89   register int i;
  90
  91   if (xports == NULL)
  92     {
  93       xports = (SVCXPRT **) calloc (_rpc_dtablesize (), sizeof (SVCXPRT *));
  94       if (xports == NULL) /* Don't add handle */
  95         return;
  96     }
  97
  98   if (sock < _rpc_dtablesize ())
  99     {
 100       struct pollfd *new_svc_pollfd;
 101
 102       xports[sock] = xprt;
 103       if (sock < FD_SETSIZE)
 104         FD_SET (sock, &svc_fdset);
 105
 106       /* Check if we have an empty slot */
 107       for (i = 0; i < svc_max_pollfd; ++i)
 108         if (svc_pollfd[i].fd == -1)
 109           {
 110             svc_pollfd[i].fd = sock;
 111             svc_pollfd[i].events = (POLLIN | POLLPRI |
 112                                     POLLRDNORM | POLLRDBAND);
 113             return;
 114           }
 115
 116       new_svc_pollfd = (struct pollfd *) realloc (svc_pollfd,
 117                                                   sizeof (struct pollfd)
 118                                                   * (svc_max_pollfd + 1));
 119       if (new_svc_pollfd == NULL) /* Out of memory */
 120         return;
 121       svc_pollfd = new_svc_pollfd;
 122       ++svc_max_pollfd;
 123
 124       svc_pollfd[svc_max_pollfd - 1].fd = sock;
 125       svc_pollfd[svc_max_pollfd - 1].events = (POLLIN | POLLPRI |
 126                                                POLLRDNORM | POLLRDBAND);
 127     }
 128 }
 129 libc_hidden_nolink_sunrpc (xprt_register, GLIBC_2_0)
 130
 131 /* De-activate a transport handle. */
 132 void
 133 xprt_unregister (SVCXPRT *xprt)
 134 {
 135   register int sock = xprt->xp_sock;
 136   register int i;
 137
 138   if ((sock < _rpc_dtablesize ()) && (xports[sock] == xprt))
 139     {
 140       xports[sock] = (SVCXPRT *) 0;
 141
 142       if (sock < FD_SETSIZE)
 143         FD_CLR (sock, &svc_fdset);
 144
 145       for (i = 0; i < svc_max_pollfd; ++i)
 146         if (svc_pollfd[i].fd == sock)
 147           svc_pollfd[i].fd = -1;
 148     }
 149 }
 150 #ifdef EXPORT_RPC_SYMBOLS
 151 libc_hidden_def (xprt_unregister)
 152 #else
 153 libc_hidden_nolink_sunrpc (xprt_unregister, GLIBC_2_0)
 154 #endif
 155
 156
 157 /* ********************** CALLOUT list related stuff ************* */
 158
 159 /* Search the callout list for a program number, return the callout
 160    struct. */
 161 static struct svc_callout *
 162 svc_find (rpcprog_t prog, rpcvers_t vers, struct svc_callout **prev)
 163 {
 164   register struct svc_callout *s, *p;
 165
 166   p = NULL_SVC;
 167   for (s = svc_head; s != NULL_SVC; s = s->sc_next)
 168     {
 169       if ((s->sc_prog == prog) && (s->sc_vers == vers))
 170         goto done;
 171       p = s;
 172     }
 173 done:
 174   *prev = p;
 175   return s;
 176 }
 177
 178 /* Add a service program to the callout list.
 179    The dispatch routine will be called when a rpc request for this
 180    program number comes in. */
 181 bool_t
 182 svc_register (SVCXPRT * xprt, rpcprog_t prog, rpcvers_t vers,
 183               void (*dispatch) (struct svc_req *, SVCXPRT *),
 184               rpcproc_t protocol)
 185 {
 186   struct svc_callout *prev;
 187   register struct svc_callout *s;
 188
 189   if ((s = svc_find (prog, vers, &prev)) != NULL_SVC)
 190     {
 191       if (s->sc_dispatch == dispatch)
 192         goto pmap_it;           /* he is registering another xptr */
 193       return FALSE;
 194     }
 195   s = (struct svc_callout *) mem_alloc (sizeof (struct svc_callout));
 196   if (s == (struct svc_callout *) 0)
 197     return FALSE;
 198
 199   s->sc_prog = prog;
 200   s->sc_vers = vers;
 201   s->sc_dispatch = dispatch;
 202   s->sc_next = svc_head;
 203   s->sc_mapped = FALSE;
 204   svc_head = s;
 205
 206 pmap_it:
 207   /* now register the information with the local binder service */
 208   if (protocol)
 209     {
 210       if (! pmap_set (prog, vers, protocol, xprt->xp_port))
 211         return FALSE;
 212
 213       s->sc_mapped = TRUE;
 214     }
 215
 216   return TRUE;
 217 }
 218 #ifdef EXPORT_RPC_SYMBOLS
 219 libc_hidden_def (svc_register)
 220 #else
 221 libc_hidden_nolink_sunrpc (svc_register, GLIBC_2_0)
 222 #endif
 223
 224 /* Remove a service program from the callout list. */
 225 void
 226 svc_unregister (rpcprog_t prog, rpcvers_t vers)
 227 {
 228   struct svc_callout *prev;
 229   register struct svc_callout *s;
 230
 231   if ((s = svc_find (prog, vers, &prev)) == NULL_SVC)
 232     return;
 233   bool is_mapped = s->sc_mapped;
 234
 235   if (prev == NULL_SVC)
 236     svc_head = s->sc_next;
 237   else
 238     prev->sc_next = s->sc_next;
 239
 240   s->sc_next = NULL_SVC;
 241   mem_free ((char *) s, (u_int) sizeof (struct svc_callout));
 242   /* now unregister the information with the local binder service */
 243   if (is_mapped)
 244     pmap_unset (prog, vers);
 245 }
 246 libc_hidden_nolink_sunrpc (svc_unregister, GLIBC_2_0)
 247
 248 /* ******************* REPLY GENERATION ROUTINES  ************ */
 249
 250 /* Send a reply to an rpc request */
 251 bool_t
 252 svc_sendreply (register SVCXPRT *xprt, xdrproc_t xdr_results,
 253                caddr_t xdr_location)
 254 {
 255   struct rpc_msg rply;
 256
 257   rply.rm_direction = REPLY;
 258   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 259   rply.acpted_rply.ar_verf = xprt->xp_verf;
 260   rply.acpted_rply.ar_stat = SUCCESS;
 261   rply.acpted_rply.ar_results.where = xdr_location;
 262   rply.acpted_rply.ar_results.proc = xdr_results;
 263   return SVC_REPLY (xprt, &rply);
 264 }
 265 #ifdef EXPORT_RPC_SYMBOLS
 266 libc_hidden_def (svc_sendreply)
 267 #else
 268 libc_hidden_nolink_sunrpc (svc_sendreply, GLIBC_2_0)
 269 #endif
 270
 271 /* No procedure error reply */
 272 void
 273 svcerr_noproc (register SVCXPRT *xprt)
 274 {
 275   struct rpc_msg rply;
 276
 277   rply.rm_direction = REPLY;
 278   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 279   rply.acpted_rply.ar_verf = xprt->xp_verf;
 280   rply.acpted_rply.ar_stat = PROC_UNAVAIL;
 281   SVC_REPLY (xprt, &rply);
 282 }
 283 #ifdef EXPORT_RPC_SYMBOLS
 284 libc_hidden_def (svcerr_noproc)
 285 #else
 286 libc_hidden_nolink_sunrpc (svcerr_noproc, GLIBC_2_0)
 287 #endif
 288
 289 /* Can't decode args error reply */
 290 void
 291 svcerr_decode (register SVCXPRT *xprt)
 292 {
 293   struct rpc_msg rply;
 294
 295   rply.rm_direction = REPLY;
 296   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 297   rply.acpted_rply.ar_verf = xprt->xp_verf;
 298   rply.acpted_rply.ar_stat = GARBAGE_ARGS;
 299   SVC_REPLY (xprt, &rply);
 300 }
 301 #ifdef EXPORT_RPC_SYMBOLS
 302 libc_hidden_def (svcerr_decode)
 303 #else
 304 libc_hidden_nolink_sunrpc (svcerr_decode, GLIBC_2_0)
 305 #endif
 306
 307 /* Some system error */
 308 void
 309 svcerr_systemerr (register SVCXPRT *xprt)
 310 {
 311   struct rpc_msg rply;
 312
 313   rply.rm_direction = REPLY;
 314   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 315   rply.acpted_rply.ar_verf = xprt->xp_verf;
 316   rply.acpted_rply.ar_stat = SYSTEM_ERR;
 317   SVC_REPLY (xprt, &rply);
 318 }
 319 #ifdef EXPORT_RPC_SYMBOLS
 320 libc_hidden_def (svcerr_systemerr)
 321 #else
 322 libc_hidden_nolink_sunrpc (svcerr_systemerr, GLIBC_2_0)
 323 #endif
 324
 325 /* Authentication error reply */
 326 void
 327 svcerr_auth (SVCXPRT *xprt, enum auth_stat why)
 328 {
 329   struct rpc_msg rply;
 330
 331   rply.rm_direction = REPLY;
 332   rply.rm_reply.rp_stat = MSG_DENIED;
 333   rply.rjcted_rply.rj_stat = AUTH_ERROR;
 334   rply.rjcted_rply.rj_why = why;
 335   SVC_REPLY (xprt, &rply);
 336 }
 337 libc_hidden_nolink_sunrpc (svcerr_auth, GLIBC_2_0)
 338
 339 /* Auth too weak error reply */
 340 void
 341 svcerr_weakauth (SVCXPRT *xprt)
 342 {
 343   svcerr_auth (xprt, AUTH_TOOWEAK);
 344 }
 345 libc_hidden_nolink_sunrpc (svcerr_weakauth, GLIBC_2_0)
 346
 347 /* Program unavailable error reply */
 348 void
 349 svcerr_noprog (register SVCXPRT *xprt)
 350 {
 351   struct rpc_msg rply;
 352
 353   rply.rm_direction = REPLY;
 354   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 355   rply.acpted_rply.ar_verf = xprt->xp_verf;
 356   rply.acpted_rply.ar_stat = PROG_UNAVAIL;
 357   SVC_REPLY (xprt, &rply);
 358 }
 359 libc_hidden_nolink_sunrpc (svcerr_noprog, GLIBC_2_0)
 360
 361 /* Program version mismatch error reply */
 362 void
 363 svcerr_progvers (register SVCXPRT *xprt, rpcvers_t low_vers,
 364                  rpcvers_t high_vers)
 365 {
 366   struct rpc_msg rply;
 367
 368   rply.rm_direction = REPLY;
 369   rply.rm_reply.rp_stat = MSG_ACCEPTED;
 370   rply.acpted_rply.ar_verf = xprt->xp_verf;
 371   rply.acpted_rply.ar_stat = PROG_MISMATCH;
 372   rply.acpted_rply.ar_vers.low = low_vers;
 373   rply.acpted_rply.ar_vers.high = high_vers;
 374   SVC_REPLY (xprt, &rply);
 375 }
 376 libc_hidden_nolink_sunrpc (svcerr_progvers, GLIBC_2_0)
 377
 378 /* ******************* SERVER INPUT STUFF ******************* */
 379
 380 /*
 381  * Get server side input from some transport.
 382  *
 383  * Statement of authentication parameters management:
 384  * This function owns and manages all authentication parameters, specifically
 385  * the "raw" parameters (msg.rm_call.cb_cred and msg.rm_call.cb_verf) and
 386  * the "cooked" credentials (rqst->rq_clntcred).
 387  * However, this function does not know the structure of the cooked
 388  * credentials, so it make the following assumptions:
 389  *   a) the structure is contiguous (no pointers), and
 390  *   b) the cred structure size does not exceed RQCRED_SIZE bytes.
 391  * In all events, all three parameters are freed upon exit from this routine.
 392  * The storage is trivially management on the call stack in user land, but
 393  * is mallocated in kernel land.
 394  */
 395
 396 void
 397 svc_getreq (int rdfds)
 398 {
 399   fd_set readfds;
 400
 401   FD_ZERO (&readfds);
 402   readfds.fds_bits[0] = rdfds;
 403   svc_getreqset (&readfds);
 404 }
 405 libc_hidden_nolink_sunrpc (svc_getreq, GLIBC_2_0)
 406
 407 void
 408 svc_getreqset (fd_set *readfds)
 409 {
 410   register fd_mask mask;
 411   register fd_mask *maskp;
 412   register int setsize;
 413   register int sock;
 414   register int bit;
 415
 416   setsize = _rpc_dtablesize ();
 417   if (setsize > FD_SETSIZE)
 418     setsize = FD_SETSIZE;
 419   maskp = readfds->fds_bits;
 420   for (sock = 0; sock < setsize; sock += NFDBITS)
 421     for (mask = *maskp++; (bit = ffsl (mask)); mask ^= (1L << (bit - 1)))
 422       svc_getreq_common (sock + bit - 1);
 423 }
 424 libc_hidden_nolink_sunrpc (svc_getreqset, GLIBC_2_0)
 425
 426 void
 427 svc_getreq_poll (struct pollfd *pfdp, int pollretval)
 428 {
 429   if (pollretval == 0)
 430     return;
 431
 432   register int fds_found;
 433   for (int i = fds_found = 0; i < svc_max_pollfd; ++i)
 434     {
 435       register struct pollfd *p = &pfdp[i];
 436
 437       if (p->fd != -1 && p->revents)
 438         {
 439           /* fd has input waiting */
 440           if (p->revents & POLLNVAL)
 441             xprt_unregister (xports[p->fd]);
 442           else
 443             svc_getreq_common (p->fd);
 444
 445           if (++fds_found >= pollretval)
 446             break;
 447         }
 448     }
 449 }
 450 #ifdef EXPORT_RPC_SYMBOLS
 451 libc_hidden_def (svc_getreq_poll)
 452 #else
 453 libc_hidden_nolink_sunrpc (svc_getreq_poll, GLIBC_2_2)
 454 #endif
 455
 456
 457 void
 458 svc_getreq_common (const int fd)
 459 {
 460   enum xprt_stat stat;
 461   struct rpc_msg msg;
 462   register SVCXPRT *xprt;
 463   char cred_area[2 * MAX_AUTH_BYTES + RQCRED_SIZE];
 464   msg.rm_call.cb_cred.oa_base = cred_area;
 465   msg.rm_call.cb_verf.oa_base = &(cred_area[MAX_AUTH_BYTES]);
 466
 467   xprt = xports[fd];
 468   /* Do we control fd? */
 469   if (xprt == NULL)
 470      return;
 471
 472   /* now receive msgs from xprtprt (support batch calls) */
 473   do
 474     {
 475       if (SVC_RECV (xprt, &msg))
 476         {
 477           /* now find the exported program and call it */
 478           struct svc_callout *s;
 479           struct svc_req r;
 480           enum auth_stat why;
 481           rpcvers_t low_vers;
 482           rpcvers_t high_vers;
 483           int prog_found;
 484
 485           r.rq_clntcred = &(cred_area[2 * MAX_AUTH_BYTES]);
 486           r.rq_xprt = xprt;
 487           r.rq_prog = msg.rm_call.cb_prog;
 488           r.rq_vers = msg.rm_call.cb_vers;
 489           r.rq_proc = msg.rm_call.cb_proc;
 490           r.rq_cred = msg.rm_call.cb_cred;
 491
 492           /* first authenticate the message */
 493           /* Check for null flavor and bypass these calls if possible */
 494
 495           if (msg.rm_call.cb_cred.oa_flavor == AUTH_NULL)
 496             {
 497               r.rq_xprt->xp_verf.oa_flavor = _null_auth.oa_flavor;
 498               r.rq_xprt->xp_verf.oa_length = 0;
 499             }
 500           else if ((why = _authenticate (&r, &msg)) != AUTH_OK)
 501             {
 502               svcerr_auth (xprt, why);
 503               goto call_done;
 504             }
 505
 506           /* now match message with a registered service */
 507           prog_found = FALSE;
 508           low_vers = 0 - 1;
 509           high_vers = 0;
 510
 511           for (s = svc_head; s != NULL_SVC; s = s->sc_next)
 512             {
 513               if (s->sc_prog == r.rq_prog)
 514                 {
 515                   if (s->sc_vers == r.rq_vers)
 516                     {
 517                       (*s->sc_dispatch) (&r, xprt);
 518                       goto call_done;
 519                     }
 520                   /* found correct version */
 521                   prog_found = TRUE;
 522                   if (s->sc_vers < low_vers)
 523                     low_vers = s->sc_vers;
 524                   if (s->sc_vers > high_vers)
 525                     high_vers = s->sc_vers;
 526                 }
 527               /* found correct program */
 528             }
 529           /* if we got here, the program or version
 530              is not served ... */
 531           if (prog_found)
 532             svcerr_progvers (xprt, low_vers, high_vers);
 533           else
 534             svcerr_noprog (xprt);
 535           /* Fall through to ... */
 536         }
 537     call_done:
 538       if ((stat = SVC_STAT (xprt)) == XPRT_DIED)
 539         {
 540           SVC_DESTROY (xprt);
 541           break;
 542         }
 543     }
 544   while (stat == XPRT_MOREREQS);
 545 }
 546 libc_hidden_nolink_sunrpc (svc_getreq_common, GLIBC_2_2)
 547
 548 /* If there are no file descriptors available, then accept will fail.
 549    We want to delay here so the connection request can be dequeued;
 550    otherwise we can bounce between polling and accepting, never giving the
 551    request a chance to dequeue and eating an enormous amount of cpu time
 552    in svc_run if we're polling on many file descriptors.  */
 553 void
 554 __svc_accept_failed (void)
 555 {
 556   if (errno == EMFILE)
 557     {
 558       struct timespec ts = { .tv_sec = 0, .tv_nsec = 50000000 };
 559       __nanosleep (&ts, NULL);
 560     }
 561 }
 562
 563
 564 void
 565 __rpc_thread_svc_cleanup (void)
 566 {
 567   struct svc_callout *svcp;
 568
 569   while ((svcp = svc_head) != NULL)
 570     svc_unregister (svcp->sc_prog, svcp->sc_vers);
 571 }