sunrpc/svc_tcp.c

   1 /*
   2  * svc_tcp.c, Server side for TCP/IP based RPC.
   3  *
   4  * Copyright (C) 2012-2021 Free Software Foundation, Inc.
   5  * This file is part of the GNU C Library.
   6  *
   7  * The GNU C Library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * The GNU C Library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with the GNU C Library; if not, see
  19  * <https://www.gnu.org/licenses/>.
  20  *
  21  * Copyright (c) 2010, Oracle America, Inc.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions are
  25  * met:
  26  *
  27  *     * Redistributions of source code must retain the above copyright
  28  *       notice, this list of conditions and the following disclaimer.
  29  *     * Redistributions in binary form must reproduce the above
  30  *       copyright notice, this list of conditions and the following
  31  *       disclaimer in the documentation and/or other materials
  32  *       provided with the distribution.
  33  *     * Neither the name of the "Oracle America, Inc." nor the names of its
  34  *       contributors may be used to endorse or promote products derived
  35  *       from this software without specific prior written permission.
  36  *
  37  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  38  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  39  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  40  *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  41  *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
  42  *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  43  *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  44  *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  45  *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  46  *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  47  *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  48  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  49  *
  50  * Actually implements two flavors of transporter -
  51  * a tcp rendezvouser (a listener and connection establisher)
  52  * and a record/tcp stream.
  53  */
  54
  55 #include <stdio.h>
  56 #include <unistd.h>
  57 #include <string.h>
  58 #include <libintl.h>
  59 #include <rpc/rpc.h>
  60 #include <sys/socket.h>
  61 #include <sys/poll.h>
  62 #include <errno.h>
  63 #include <stdlib.h>
  64
  65 #include <wchar.h>
  66 #include <libio/iolibio.h>
  67 #include <shlib-compat.h>
  68
  69 /*
  70  * Ops vector for TCP/IP based rpc service handle
  71  */
  72 static bool_t svctcp_recv (SVCXPRT *, struct rpc_msg *);
  73 static enum xprt_stat svctcp_stat (SVCXPRT *);
  74 static bool_t svctcp_getargs (SVCXPRT *, xdrproc_t, caddr_t);
  75 static bool_t svctcp_reply (SVCXPRT *, struct rpc_msg *);
  76 static bool_t svctcp_freeargs (SVCXPRT *, xdrproc_t, caddr_t);
  77 static void svctcp_destroy (SVCXPRT *);
  78
  79 static const struct xp_ops svctcp_op =
  80 {
  81   svctcp_recv,
  82   svctcp_stat,
  83   svctcp_getargs,
  84   svctcp_reply,
  85   svctcp_freeargs,
  86   svctcp_destroy
  87 };
  88
  89 /*
  90  * Ops vector for TCP/IP rendezvous handler
  91  */
  92 static bool_t rendezvous_request (SVCXPRT *, struct rpc_msg *);
  93 static enum xprt_stat rendezvous_stat (SVCXPRT *);
  94 static void svctcp_rendezvous_abort (void) __attribute__ ((__noreturn__));
  95
  96 /* This function makes sure abort() relocation goes through PLT
  97    and thus can be lazy bound.  */
  98 static void
  99 svctcp_rendezvous_abort (void)
 100 {
 101   abort ();
 102 };
 103
 104 static const struct xp_ops svctcp_rendezvous_op =
 105 {
 106   rendezvous_request,
 107   rendezvous_stat,
 108   (bool_t (*) (SVCXPRT *, xdrproc_t, caddr_t)) svctcp_rendezvous_abort,
 109   (bool_t (*) (SVCXPRT *, struct rpc_msg *)) svctcp_rendezvous_abort,
 110   (bool_t (*) (SVCXPRT *, xdrproc_t, caddr_t)) svctcp_rendezvous_abort,
 111   svctcp_destroy
 112 };
 113
 114 static int readtcp (char*, char *, int);
 115 static int writetcp (char *, char *, int);
 116 static SVCXPRT *makefd_xprt (int, u_int, u_int);
 117
 118 struct tcp_rendezvous
 119   {                             /* kept in xprt->xp_p1 */
 120     u_int sendsize;
 121     u_int recvsize;
 122   };
 123
 124 struct tcp_conn
 125   {                             /* kept in xprt->xp_p1 */
 126     enum xprt_stat strm_stat;
 127     u_long x_id;
 128     XDR xdrs;
 129     char verf_body[MAX_AUTH_BYTES];
 130   };
 131
 132 /*
 133  * Usage:
 134  *      xprt = svctcp_create(sock, send_buf_size, recv_buf_size);
 135  *
 136  * Creates, registers, and returns a (rpc) tcp based transporter.
 137  * Once *xprt is initialized, it is registered as a transporter
 138  * see (svc.h, xprt_register).  This routine returns
 139  * a NULL if a problem occurred.
 140  *
 141  * If sock<0 then a socket is created, else sock is used.
 142  * If the socket, sock is not bound to a port then svctcp_create
 143  * binds it to an arbitrary port.  The routine then starts a tcp
 144  * listener on the socket's associated port.  In any (successful) case,
 145  * xprt->xp_sock is the registered socket number and xprt->xp_port is the
 146  * associated port number.
 147  *
 148  * Since tcp streams do buffered io similar to stdio, the caller can specify
 149  * how big the send and receive buffers are via the second and third parms;
 150  * 0 => use the system default.
 151  */
 152 SVCXPRT *
 153 svctcp_create (int sock, u_int sendsize, u_int recvsize)
 154 {
 155   bool_t madesock = FALSE;
 156   SVCXPRT *xprt;
 157   struct tcp_rendezvous *r;
 158   struct sockaddr_in addr;
 159   socklen_t len = sizeof (struct sockaddr_in);
 160
 161   if (sock == RPC_ANYSOCK)
 162     {
 163       if ((sock = __socket (AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
 164         {
 165           perror (_("svc_tcp.c - tcp socket creation problem"));
 166           return (SVCXPRT *) NULL;
 167         }
 168       madesock = TRUE;
 169     }
 170   memset ((char *) &addr, 0, sizeof (addr));
 171   addr.sin_family = AF_INET;
 172   if (bindresvport (sock, &addr))
 173     {
 174       addr.sin_port = 0;
 175       (void) __bind (sock, (struct sockaddr *) &addr, len);
 176     }
 177   if ((__getsockname (sock, (struct sockaddr *) &addr, &len) != 0) ||
 178       (__listen (sock, SOMAXCONN) != 0))
 179     {
 180       perror (_("svc_tcp.c - cannot getsockname or listen"));
 181       if (madesock)
 182         (void) __close (sock);
 183       return (SVCXPRT *) NULL;
 184     }
 185   r = (struct tcp_rendezvous *) mem_alloc (sizeof (*r));
 186   xprt = (SVCXPRT *) mem_alloc (sizeof (SVCXPRT));
 187   if (r == NULL || xprt == NULL)
 188     {
 189       (void) __fxprintf (NULL, "%s: %s", __func__, _("out of memory\n"));
 190       mem_free (r, sizeof (*r));
 191       mem_free (xprt, sizeof (SVCXPRT));
 192       return NULL;
 193     }
 194   r->sendsize = sendsize;
 195   r->recvsize = recvsize;
 196   xprt->xp_p2 = NULL;
 197   xprt->xp_p1 = (caddr_t) r;
 198   xprt->xp_verf = _null_auth;
 199   xprt->xp_ops = &svctcp_rendezvous_op;
 200   xprt->xp_port = ntohs (addr.sin_port);
 201   xprt->xp_sock = sock;
 202   xprt_register (xprt);
 203   return xprt;
 204 }
 205 #ifdef EXPORT_RPC_SYMBOLS
 206 libc_hidden_def (svctcp_create)
 207 #else
 208 libc_hidden_nolink_sunrpc (svctcp_create, GLIBC_2_0)
 209 #endif
 210
 211 /*
 212  * Like svtcp_create(), except the routine takes any *open* UNIX file
 213  * descriptor as its first input.
 214  */
 215 SVCXPRT *
 216 svcfd_create (int fd, u_int sendsize, u_int recvsize)
 217 {
 218   return makefd_xprt (fd, sendsize, recvsize);
 219 }
 220 libc_hidden_nolink_sunrpc (svcfd_create, GLIBC_2_0)
 221
 222 static SVCXPRT *
 223 makefd_xprt (int fd, u_int sendsize, u_int recvsize)
 224 {
 225   SVCXPRT *xprt;
 226   struct tcp_conn *cd;
 227
 228   xprt = (SVCXPRT *) mem_alloc (sizeof (SVCXPRT));
 229   cd = (struct tcp_conn *) mem_alloc (sizeof (struct tcp_conn));
 230   if (xprt == (SVCXPRT *) NULL || cd == NULL)
 231     {
 232       (void) __fxprintf (NULL, "%s: %s", "svc_tcp: makefd_xprt",
 233                          _("out of memory\n"));
 234       mem_free (xprt, sizeof (SVCXPRT));
 235       mem_free (cd, sizeof (struct tcp_conn));
 236       return NULL;
 237     }
 238   cd->strm_stat = XPRT_IDLE;
 239   xdrrec_create (&(cd->xdrs), sendsize, recvsize,
 240                  (caddr_t) xprt, readtcp, writetcp);
 241   xprt->xp_p2 = NULL;
 242   xprt->xp_p1 = (caddr_t) cd;
 243   xprt->xp_verf.oa_base = cd->verf_body;
 244   xprt->xp_addrlen = 0;
 245   xprt->xp_ops = &svctcp_op;    /* truly deals with calls */
 246   xprt->xp_port = 0;            /* this is a connection, not a rendezvouser */
 247   xprt->xp_sock = fd;
 248   xprt_register (xprt);
 249   return xprt;
 250 }
 251
 252 static bool_t
 253 rendezvous_request (SVCXPRT *xprt, struct rpc_msg *errmsg)
 254 {
 255   int sock;
 256   struct tcp_rendezvous *r;
 257   struct sockaddr_in addr;
 258   socklen_t len;
 259
 260   r = (struct tcp_rendezvous *) xprt->xp_p1;
 261 again:
 262   len = sizeof (struct sockaddr_in);
 263   if ((sock = accept (xprt->xp_sock, (struct sockaddr *) &addr, &len)) < 0)
 264     {
 265       if (errno == EINTR)
 266         goto again;
 267       __svc_accept_failed ();
 268       return FALSE;
 269     }
 270   /*
 271    * make a new transporter (re-uses xprt)
 272    */
 273   xprt = makefd_xprt (sock, r->sendsize, r->recvsize);
 274
 275   /* If we are out of memory, makefd_xprt has already dumped an error.  */
 276   if (xprt == NULL)
 277     {
 278       __svc_wait_on_error ();
 279       return FALSE;
 280     }
 281
 282   memcpy (&xprt->xp_raddr, &addr, sizeof (addr));
 283   xprt->xp_addrlen = len;
 284   return FALSE;         /* there is never an rpc msg to be processed */
 285 }
 286
 287 static enum xprt_stat
 288 rendezvous_stat (SVCXPRT *xprt)
 289 {
 290   return XPRT_IDLE;
 291 }
 292
 293 static void
 294 svctcp_destroy (SVCXPRT *xprt)
 295 {
 296   struct tcp_conn *cd = (struct tcp_conn *) xprt->xp_p1;
 297
 298   xprt_unregister (xprt);
 299   (void) __close (xprt->xp_sock);
 300   if (xprt->xp_port != 0)
 301     {
 302       /* a rendezvouser socket */
 303       xprt->xp_port = 0;
 304     }
 305   else
 306     {
 307       /* an actual connection socket */
 308       XDR_DESTROY (&(cd->xdrs));
 309     }
 310   mem_free ((caddr_t) cd, sizeof (struct tcp_conn));
 311   mem_free ((caddr_t) xprt, sizeof (SVCXPRT));
 312 }
 313
 314
 315 /*
 316  * reads data from the tcp connection.
 317  * any error is fatal and the connection is closed.
 318  * (And a read of zero bytes is a half closed stream => error.)
 319  */
 320 static int
 321 readtcp (char *xprtptr, char *buf, int len)
 322 {
 323   SVCXPRT *xprt = (SVCXPRT *)xprtptr;
 324   int sock = xprt->xp_sock;
 325   int milliseconds = 35 * 1000;
 326   struct pollfd pollfd;
 327
 328   do
 329     {
 330       pollfd.fd = sock;
 331       pollfd.events = POLLIN;
 332       switch (__poll (&pollfd, 1, milliseconds))
 333         {
 334         case -1:
 335           if (errno == EINTR)
 336             continue;
 337           /*FALLTHROUGH*/
 338         case 0:
 339           goto fatal_err;
 340         default:
 341           if ((pollfd.revents & POLLERR) || (pollfd.revents & POLLHUP)
 342               || (pollfd.revents & POLLNVAL))
 343             goto fatal_err;
 344           break;
 345         }
 346     }
 347   while ((pollfd.revents & POLLIN) == 0);
 348
 349   if ((len = __read (sock, buf, len)) > 0)
 350     return len;
 351
 352  fatal_err:
 353   ((struct tcp_conn *) (xprt->xp_p1))->strm_stat = XPRT_DIED;
 354   return -1;
 355 }
 356
 357 /*
 358  * writes data to the tcp connection.
 359  * Any error is fatal and the connection is closed.
 360  */
 361 static int
 362 writetcp (char *xprtptr, char * buf, int len)
 363 {
 364   SVCXPRT *xprt = (SVCXPRT *)xprtptr;
 365   int i, cnt;
 366
 367   for (cnt = len; cnt > 0; cnt -= i, buf += i)
 368     {
 369       if ((i = __write (xprt->xp_sock, buf, cnt)) < 0)
 370         {
 371           ((struct tcp_conn *) (xprt->xp_p1))->strm_stat = XPRT_DIED;
 372           return -1;
 373         }
 374     }
 375   return len;
 376 }
 377
 378 static enum xprt_stat
 379 svctcp_stat (SVCXPRT *xprt)
 380 {
 381   struct tcp_conn *cd =
 382   (struct tcp_conn *) (xprt->xp_p1);
 383
 384   if (cd->strm_stat == XPRT_DIED)
 385     return XPRT_DIED;
 386   if (!xdrrec_eof (&(cd->xdrs)))
 387     return XPRT_MOREREQS;
 388   return XPRT_IDLE;
 389 }
 390
 391 static bool_t
 392 svctcp_recv (SVCXPRT *xprt, struct rpc_msg *msg)
 393 {
 394   struct tcp_conn *cd = (struct tcp_conn *) (xprt->xp_p1);
 395   XDR *xdrs = &(cd->xdrs);
 396
 397   xdrs->x_op = XDR_DECODE;
 398   (void) xdrrec_skiprecord (xdrs);
 399   if (xdr_callmsg (xdrs, msg))
 400     {
 401       cd->x_id = msg->rm_xid;
 402       return TRUE;
 403     }
 404   cd->strm_stat = XPRT_DIED;    /* XXXX */
 405   return FALSE;
 406 }
 407
 408 static bool_t
 409 svctcp_getargs (SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)
 410 {
 411   return ((*xdr_args) (&(((struct tcp_conn *)
 412                           (xprt->xp_p1))->xdrs), args_ptr));
 413 }
 414
 415 static bool_t
 416 svctcp_freeargs (SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)
 417 {
 418   XDR *xdrs = &(((struct tcp_conn *) (xprt->xp_p1))->xdrs);
 419
 420   xdrs->x_op = XDR_FREE;
 421   return ((*xdr_args) (xdrs, args_ptr));
 422 }
 423
 424 static bool_t
 425 svctcp_reply (SVCXPRT *xprt, struct rpc_msg *msg)
 426 {
 427   struct tcp_conn *cd = (struct tcp_conn *) (xprt->xp_p1);
 428   XDR *xdrs = &(cd->xdrs);
 429   bool_t stat;
 430
 431   xdrs->x_op = XDR_ENCODE;
 432   msg->rm_xid = cd->x_id;
 433   stat = xdr_replymsg (xdrs, msg);
 434   (void) xdrrec_endofrecord (xdrs, TRUE);
 435   return stat;
 436 }