socket.c

   1 /* -*- c-file-style: "linux" -*-
   2
   3    rsync -- fast file replication program
   4
   5    Copyright (C) 1992-2001 by Andrew Tridgell <tridge@samba.org>
   6    Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org>
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 /**
  24  * @file socket.c
  25  *
  26  * Socket functions used in rsync.
  27  *
  28  * This file is now converted to use the new-style getaddrinfo()
  29  * interface, which supports IPv6 but is also supported on recent
  30  * IPv4-only machines.  On systems that don't have that interface, we
  31  * emulate it using the KAME implementation.
  32  **/
  33
  34 #include "rsync.h"
  35
  36 extern char *bind_address;
  37 extern int default_af_hint;
  38
  39 #ifdef HAVE_SIGACTION
  40 static struct sigaction sigact;
  41 #endif
  42
  43 /**
  44  * Establish a proxy connection on an open socket to a web proxy by
  45  * using the CONNECT method. If proxy_user and proxy_pass are not NULL,
  46  * they are used to authenticate to the proxy using the "Basic"
  47  * proxy-authorization protocol
  48  **/
  49 static int establish_proxy_connection(int fd, char *host, int port,
  50                                       char *proxy_user, char *proxy_pass)
  51 {
  52         char *cp, buffer[1024];
  53         char *authhdr, authbuf[1024];
  54         int len;
  55
  56         if (proxy_user && proxy_pass) {
  57                 stringjoin(buffer, sizeof buffer,
  58                          proxy_user, ":", proxy_pass, NULL);
  59                 len = strlen(buffer);
  60
  61                 if ((len*8 + 5) / 6 >= (int)sizeof authbuf) {
  62                         rprintf(FERROR,
  63                                 "authentication information is too long\n");
  64                         return -1;
  65                 }
  66
  67                 base64_encode(buffer, len, authbuf);
  68                 authhdr = "\r\nProxy-Authorization: Basic ";
  69         } else {
  70                 *authbuf = '\0';
  71                 authhdr = "";
  72         }
  73
  74         snprintf(buffer, sizeof buffer, "CONNECT %s:%d HTTP/1.0%s%s\r\n\r\n",
  75                  host, port, authhdr, authbuf);
  76         len = strlen(buffer);
  77         if (write(fd, buffer, len) != len) {
  78                 rsyserr(FERROR, errno, "failed to write to proxy");
  79                 return -1;
  80         }
  81
  82         for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {
  83                 if (read(fd, cp, 1) != 1) {
  84                         rsyserr(FERROR, errno, "failed to read from proxy");
  85                         return -1;
  86                 }
  87                 if (*cp == '\n')
  88                         break;
  89         }
  90
  91         if (*cp != '\n')
  92                 cp++;
  93         *cp-- = '\0';
  94         if (*cp == '\r')
  95                 *cp = '\0';
  96         if (strncmp(buffer, "HTTP/", 5) != 0) {
  97                 rprintf(FERROR, "bad response from proxy -- %s\n",
  98                         buffer);
  99                 return -1;
 100         }
 101         for (cp = &buffer[5]; isdigit(*(uchar*)cp) || *cp == '.'; cp++) {}
 102         while (*cp == ' ')
 103                 cp++;
 104         if (*cp != '2') {
 105                 rprintf(FERROR, "bad response from proxy -- %s\n",
 106                         buffer);
 107                 return -1;
 108         }
 109         /* throw away the rest of the HTTP header */
 110         while (1) {
 111                 for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {
 112                         if (read(fd, cp, 1) != 1) {
 113                                 rsyserr(FERROR, errno,
 114                                         "failed to read from proxy");
 115                                 return -1;
 116                         }
 117                         if (*cp == '\n')
 118                                 break;
 119                 }
 120                 if (cp > buffer && *cp == '\n')
 121                         cp--;
 122                 if (cp == buffer && (*cp == '\n' || *cp == '\r'))
 123                         break;
 124         }
 125         return 0;
 126 }
 127
 128
 129 /**
 130  * Try to set the local address for a newly-created socket.  Return -1
 131  * if this fails.
 132  **/
 133 int try_bind_local(int s, int ai_family, int ai_socktype,
 134                    const char *bind_addr)
 135 {
 136         int error;
 137         struct addrinfo bhints, *bres_all, *r;
 138
 139         memset(&bhints, 0, sizeof bhints);
 140         bhints.ai_family = ai_family;
 141         bhints.ai_socktype = ai_socktype;
 142         bhints.ai_flags = AI_PASSIVE;
 143         if ((error = getaddrinfo(bind_addr, NULL, &bhints, &bres_all))) {
 144                 rprintf(FERROR, RSYNC_NAME ": getaddrinfo %s: %s\n",
 145                         bind_addr, gai_strerror(error));
 146                 return -1;
 147         }
 148
 149         for (r = bres_all; r; r = r->ai_next) {
 150                 if (bind(s, r->ai_addr, r->ai_addrlen) == -1)
 151                         continue;
 152                 freeaddrinfo(bres_all);
 153                 return s;
 154         }
 155
 156         /* no error message; there might be some problem that allows
 157          * creation of the socket but not binding, perhaps if the
 158          * machine has no ipv6 address of this name. */
 159         freeaddrinfo(bres_all);
 160         return -1;
 161 }
 162
 163
 164 /**
 165  * Open a socket to a tcp remote host with the specified port .
 166  *
 167  * Based on code from Warren.  Proxy support by Stephen Rothwell.
 168  * getaddrinfo() rewrite contributed by KAME.net.
 169  *
 170  * Now that we support IPv6 we need to look up the remote machine's
 171  * address first, using @p af_hint to set a preference for the type
 172  * of address.  Then depending on whether it has v4 or v6 addresses we
 173  * try to open a connection.
 174  *
 175  * The loop allows for machines with some addresses which may not be
 176  * reachable, perhaps because we can't e.g. route ipv6 to that network
 177  * but we can get ip4 packets through.
 178  *
 179  * @param bind_addr Local address to use.  Normally NULL to bind
 180  * the wildcard address.
 181  *
 182  * @param af_hint Address family, e.g. AF_INET or AF_INET6.
 183  **/
 184 int open_socket_out(char *host, int port, const char *bind_addr,
 185                     int af_hint)
 186 {
 187         int type = SOCK_STREAM;
 188         int error, s;
 189         struct addrinfo hints, *res0, *res;
 190         char portbuf[10];
 191         char *h, *cp;
 192         int proxied = 0;
 193         char buffer[1024];
 194         char *proxy_user = NULL, *proxy_pass = NULL;
 195
 196         /* if we have a RSYNC_PROXY env variable then redirect our
 197          * connetcion via a web proxy at the given address. */
 198         h = getenv("RSYNC_PROXY");
 199         proxied = h != NULL && *h != '\0';
 200
 201         if (proxied) {
 202                 strlcpy(buffer, h, sizeof buffer);
 203
 204                 /* Is the USER:PASS@ prefix present? */
 205                 if ((cp = strrchr(buffer, '@')) != NULL) {
 206                         *cp++ = '\0';
 207                         /* The remainder is the HOST:PORT part. */
 208                         h = cp;
 209
 210                         if ((cp = strchr(buffer, ':')) == NULL) {
 211                                 rprintf(FERROR,
 212                                         "invalid proxy specification: should be USER:PASS@HOST:PORT\n");
 213                                 return -1;
 214                         }
 215                         *cp++ = '\0';
 216
 217                         proxy_user = buffer;
 218                         proxy_pass = cp;
 219                 } else {
 220                         /* The whole buffer is the HOST:PORT part. */
 221                         h = buffer;
 222                 }
 223
 224                 if ((cp = strchr(h, ':')) == NULL) {
 225                         rprintf(FERROR,
 226                                 "invalid proxy specification: should be HOST:PORT\n");
 227                         return -1;
 228                 }
 229                 *cp++ = '\0';
 230                 strlcpy(portbuf, cp, sizeof portbuf);
 231                 if (verbose >= 2) {
 232                         rprintf(FINFO, "connection via http proxy %s port %s\n",
 233                                 h, portbuf);
 234                 }
 235         } else {
 236                 snprintf(portbuf, sizeof portbuf, "%d", port);
 237                 h = host;
 238         }
 239
 240         memset(&hints, 0, sizeof hints);
 241         hints.ai_family = af_hint;
 242         hints.ai_socktype = type;
 243         error = getaddrinfo(h, portbuf, &hints, &res0);
 244         if (error) {
 245                 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: %s %s: %s\n",
 246                         h, portbuf, gai_strerror(error));
 247                 return -1;
 248         }
 249
 250         s = -1;
 251         /* Try to connect to all addresses for this machine until we get
 252          * through.  It might e.g. be multi-homed, or have both IPv4 and IPv6
 253          * addresses.  We need to create a socket for each record, since the
 254          * address record tells us what protocol to use to try to connect. */
 255         for (res = res0; res; res = res->ai_next) {
 256                 s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
 257                 if (s < 0)
 258                         continue;
 259
 260                 if (bind_addr
 261                  && try_bind_local(s, res->ai_family, type,
 262                                    bind_addr) == -1) {
 263                         close(s);
 264                         s = -1;
 265                         continue;
 266                 }
 267                 if (connect(s, res->ai_addr, res->ai_addrlen) < 0) {
 268                         close(s);
 269                         s = -1;
 270                         continue;
 271                 }
 272                 if (proxied
 273                  && establish_proxy_connection(s, host, port,
 274                                                proxy_user, proxy_pass) != 0) {
 275                         close(s);
 276                         s = -1;
 277                         continue;
 278                 }
 279                 break;
 280         }
 281         freeaddrinfo(res0);
 282         if (s < 0) {
 283                 rsyserr(FERROR, errno, "failed to connect to %s", h);
 284                 return -1;
 285         }
 286         return s;
 287 }
 288
 289
 290 /**
 291  * Open an outgoing socket, but allow for it to be intercepted by
 292  * $RSYNC_CONNECT_PROG, which will execute a program across a TCP
 293  * socketpair rather than really opening a socket.
 294  *
 295  * We use this primarily in testing to detect TCP flow bugs, but not
 296  * cause security problems by really opening remote connections.
 297  *
 298  * This is based on the Samba LIBSMB_PROG feature.
 299  *
 300  * @param bind_addr Local address to use.  Normally NULL to get the stack default.
 301  **/
 302 int open_socket_out_wrapped(char *host, int port, const char *bind_addr,
 303                             int af_hint)
 304 {
 305         char *prog = getenv("RSYNC_CONNECT_PROG");
 306
 307         if (verbose >= 2) {
 308                 rprintf(FINFO, "%sopening tcp connection to %s port %d\n",
 309                         prog ? "Using RSYNC_CONNECT_PROG instead of " : "",
 310                         host, port);
 311         }
 312         if (prog)
 313                 return sock_exec(prog);
 314         return open_socket_out(host, port, bind_addr, af_hint);
 315 }
 316
 317
 318
 319 /**
 320  * Open one or more sockets for incoming data using the specified type,
 321  * port, and address.
 322  *
 323  * The getaddrinfo() call may return several address results, e.g. for
 324  * the machine's IPv4 and IPv6 name.
 325  *
 326  * We return an array of file-descriptors to the sockets, with a trailing
 327  * -1 value to indicate the end of the list.
 328  *
 329  * @param bind_addr Local address to bind, or NULL to allow it to
 330  * default.
 331  **/
 332 static int *open_socket_in(int type, int port, const char *bind_addr,
 333                            int af_hint)
 334 {
 335         int one = 1;
 336         int s, *socks, maxs, i;
 337         struct addrinfo hints, *all_ai, *resp;
 338         char portbuf[10];
 339         int error;
 340
 341         memset(&hints, 0, sizeof hints);
 342         hints.ai_family = af_hint;
 343         hints.ai_socktype = type;
 344         hints.ai_flags = AI_PASSIVE;
 345         snprintf(portbuf, sizeof portbuf, "%d", port);
 346         error = getaddrinfo(bind_addr, portbuf, &hints, &all_ai);
 347         if (error) {
 348                 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: %s\n",
 349                         bind_addr, gai_strerror(error));
 350                 return NULL;
 351         }
 352
 353         /* Count max number of sockets we might open. */
 354         for (maxs = 0, resp = all_ai; resp; resp = resp->ai_next, maxs++) {}
 355
 356         if (!(socks = new_array(int, maxs + 1)))
 357                 out_of_memory("open_socket_in");
 358
 359         /* We may not be able to create the socket, if for example the
 360          * machine knows about IPv6 in the C library, but not in the
 361          * kernel. */
 362         for (resp = all_ai, i = 0; resp; resp = resp->ai_next) {
 363                 s = socket(resp->ai_family, resp->ai_socktype,
 364                            resp->ai_protocol);
 365
 366                 if (s == -1) {
 367                         /* See if there's another address that will work... */
 368                         continue;
 369                 }
 370
 371                 setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
 372                            (char *)&one, sizeof one);
 373
 374 #ifdef IPV6_V6ONLY
 375                 if (resp->ai_family == AF_INET6) {
 376                         if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
 377                                        (char *)&one, sizeof one) < 0
 378                             && default_af_hint != AF_INET6) {
 379                                 close(s);
 380                                 continue;
 381                         }
 382                 }
 383 #endif
 384
 385                 /* Now we've got a socket - we need to bind it. */
 386                 if (bind(s, resp->ai_addr, resp->ai_addrlen) < 0) {
 387                         /* Nope, try another */
 388                         close(s);
 389                         continue;
 390                 }
 391
 392                 socks[i++] = s;
 393         }
 394         socks[i] = -1;
 395
 396         if (all_ai)
 397                 freeaddrinfo(all_ai);
 398
 399         if (!i) {
 400                 rprintf(FERROR,
 401                         "unable to bind any inbound sockets on port %d\n",
 402                         port);
 403                 free(socks);
 404                 return NULL;
 405         }
 406         return socks;
 407 }
 408
 409
 410 /*
 411  * Determine if a file descriptor is in fact a socket
 412  */
 413 int is_a_socket(int fd)
 414 {
 415         int v;
 416         socklen_t l = sizeof (int);
 417
 418         /* Parameters to getsockopt, setsockopt etc are very
 419          * unstandardized across platforms, so don't be surprised if
 420          * there are compiler warnings on e.g. SCO OpenSwerver or AIX.
 421          * It seems they all eventually get the right idea.
 422          *
 423          * Debian says: ``The fifth argument of getsockopt and
 424          * setsockopt is in reality an int [*] (and this is what BSD
 425          * 4.* and libc4 and libc5 have).  Some POSIX confusion
 426          * resulted in the present socklen_t.  The draft standard has
 427          * not been adopted yet, but glibc2 already follows it and
 428          * also has socklen_t [*]. See also accept(2).''
 429          *
 430          * We now return to your regularly scheduled programming.  */
 431         return getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0;
 432 }
 433
 434
 435 static RETSIGTYPE sigchld_handler(UNUSED(int val))
 436 {
 437 #ifdef WNOHANG
 438         while (waitpid(-1, NULL, WNOHANG) > 0) {}
 439 #endif
 440 #ifndef HAVE_SIGACTION
 441         signal(SIGCHLD, sigchld_handler);
 442 #endif
 443 }
 444
 445
 446 void start_accept_loop(int port, int (*fn)(int, int))
 447 {
 448         fd_set deffds;
 449         int *sp, maxfd, i;
 450
 451 #ifdef HAVE_SIGACTION
 452         sigact.sa_flags = SA_NOCLDSTOP;
 453 #endif
 454
 455         /* open an incoming socket */
 456         sp = open_socket_in(SOCK_STREAM, port, bind_address, default_af_hint);
 457         if (sp == NULL)
 458                 exit_cleanup(RERR_SOCKETIO);
 459
 460         /* ready to listen */
 461         FD_ZERO(&deffds);
 462         for (i = 0, maxfd = -1; sp[i] >= 0; i++) {
 463                 if (listen(sp[i], 5) < 0) {
 464                         rsyserr(FERROR, errno, "listen() on socket failed");
 465 #ifdef INET6
 466                         if (errno == EADDRINUSE && i > 0) {
 467                                 rprintf(FINFO,
 468                                     "Try using --ipv4 or --ipv6 to avoid this listen() error.\n");
 469                         }
 470 #endif
 471                         exit_cleanup(RERR_SOCKETIO);
 472                 }
 473                 FD_SET(sp[i], &deffds);
 474                 if (maxfd < sp[i])
 475                         maxfd = sp[i];
 476         }
 477
 478         /* now accept incoming connections - forking a new process
 479          * for each incoming connection */
 480         while (1) {
 481                 fd_set fds;
 482                 pid_t pid;
 483                 int fd;
 484                 struct sockaddr_storage addr;
 485                 socklen_t addrlen = sizeof addr;
 486
 487                 /* close log file before the potentially very long select so
 488                  * file can be trimmed by another process instead of growing
 489                  * forever */
 490                 logfile_close();
 491
 492 #ifdef FD_COPY
 493                 FD_COPY(&deffds, &fds);
 494 #else
 495                 fds = deffds;
 496 #endif
 497
 498                 if (select(maxfd + 1, &fds, NULL, NULL, NULL) != 1)
 499                         continue;
 500
 501                 for (i = 0, fd = -1; sp[i] >= 0; i++) {
 502                         if (FD_ISSET(sp[i], &fds)) {
 503                                 fd = accept(sp[i], (struct sockaddr *)&addr,
 504                                             &addrlen);
 505                                 break;
 506                         }
 507                 }
 508
 509                 if (fd < 0)
 510                         continue;
 511
 512                 SIGACTION(SIGCHLD, sigchld_handler);
 513
 514                 if ((pid = fork()) == 0) {
 515                         int ret;
 516                         for (i = 0; sp[i] >= 0; i++)
 517                                 close(sp[i]);
 518                         /* Re-open log file in child before possibly giving
 519                          * up privileges (see logfile_close() above). */
 520                         logfile_reopen();
 521                         ret = fn(fd, fd);
 522                         close_all();
 523                         _exit(ret);
 524                 } else if (pid < 0) {
 525                         rsyserr(FERROR, errno,
 526                                 "could not create child server process");
 527                         close(fd);
 528                         /* This might have happened because we're
 529                          * overloaded.  Sleep briefly before trying to
 530                          * accept again. */
 531                         sleep(2);
 532                 } else {
 533                         /* Parent doesn't need this fd anymore. */
 534                         close(fd);
 535                 }
 536         }
 537 }
 538
 539
 540 enum SOCK_OPT_TYPES {OPT_BOOL,OPT_INT,OPT_ON};
 541
 542 struct
 543 {
 544   char *name;
 545   int level;
 546   int option;
 547   int value;
 548   int opttype;
 549 } socket_options[] = {
 550   {"SO_KEEPALIVE",      SOL_SOCKET,    SO_KEEPALIVE,    0,                 OPT_BOOL},
 551   {"SO_REUSEADDR",      SOL_SOCKET,    SO_REUSEADDR,    0,                 OPT_BOOL},
 552   {"SO_BROADCAST",      SOL_SOCKET,    SO_BROADCAST,    0,                 OPT_BOOL},
 553 #ifdef TCP_NODELAY
 554   {"TCP_NODELAY",       IPPROTO_TCP,   TCP_NODELAY,     0,                 OPT_BOOL},
 555 #endif
 556 #ifdef IPTOS_LOWDELAY
 557   {"IPTOS_LOWDELAY",    IPPROTO_IP,    IP_TOS,          IPTOS_LOWDELAY,    OPT_ON},
 558 #endif
 559 #ifdef IPTOS_THROUGHPUT
 560   {"IPTOS_THROUGHPUT",  IPPROTO_IP,    IP_TOS,          IPTOS_THROUGHPUT,  OPT_ON},
 561 #endif
 562 #ifdef SO_SNDBUF
 563   {"SO_SNDBUF",         SOL_SOCKET,    SO_SNDBUF,       0,                 OPT_INT},
 564 #endif
 565 #ifdef SO_RCVBUF
 566   {"SO_RCVBUF",         SOL_SOCKET,    SO_RCVBUF,       0,                 OPT_INT},
 567 #endif
 568 #ifdef SO_SNDLOWAT
 569   {"SO_SNDLOWAT",       SOL_SOCKET,    SO_SNDLOWAT,     0,                 OPT_INT},
 570 #endif
 571 #ifdef SO_RCVLOWAT
 572   {"SO_RCVLOWAT",       SOL_SOCKET,    SO_RCVLOWAT,     0,                 OPT_INT},
 573 #endif
 574 #ifdef SO_SNDTIMEO
 575   {"SO_SNDTIMEO",       SOL_SOCKET,    SO_SNDTIMEO,     0,                 OPT_INT},
 576 #endif
 577 #ifdef SO_RCVTIMEO
 578   {"SO_RCVTIMEO",       SOL_SOCKET,    SO_RCVTIMEO,     0,                 OPT_INT},
 579 #endif
 580   {NULL,0,0,0,0}};
 581
 582
 583
 584 /**
 585  * Set user socket options
 586  **/
 587 void set_socket_options(int fd, char *options)
 588 {
 589         char *tok;
 590
 591         if (!options || !*options)
 592                 return;
 593
 594         options = strdup(options);
 595
 596         if (!options)
 597                 out_of_memory("set_socket_options");
 598
 599         for (tok = strtok(options, " \t,"); tok; tok = strtok(NULL," \t,")) {
 600                 int ret=0,i;
 601                 int value = 1;
 602                 char *p;
 603                 int got_value = 0;
 604
 605                 if ((p = strchr(tok,'='))) {
 606                         *p = 0;
 607                         value = atoi(p+1);
 608                         got_value = 1;
 609                 }
 610
 611                 for (i = 0; socket_options[i].name; i++) {
 612                         if (strcmp(socket_options[i].name,tok)==0)
 613                                 break;
 614                 }
 615
 616                 if (!socket_options[i].name) {
 617                         rprintf(FERROR,"Unknown socket option %s\n",tok);
 618                         continue;
 619                 }
 620
 621                 switch (socket_options[i].opttype) {
 622                 case OPT_BOOL:
 623                 case OPT_INT:
 624                         ret = setsockopt(fd,socket_options[i].level,
 625                                          socket_options[i].option,
 626                                          (char *)&value, sizeof (int));
 627                         break;
 628
 629                 case OPT_ON:
 630                         if (got_value)
 631                                 rprintf(FERROR,"syntax error -- %s does not take a value\n",tok);
 632
 633                         {
 634                                 int on = socket_options[i].value;
 635                                 ret = setsockopt(fd,socket_options[i].level,
 636                                                  socket_options[i].option,
 637                                                  (char *)&on, sizeof (int));
 638                         }
 639                         break;
 640                 }
 641
 642                 if (ret != 0) {
 643                         rsyserr(FERROR, errno,
 644                                 "failed to set socket option %s", tok);
 645                 }
 646         }
 647
 648         free(options);
 649 }
 650
 651 /**
 652  * Become a daemon, discarding the controlling terminal
 653  **/
 654 void become_daemon(void)
 655 {
 656         int i;
 657
 658         if (fork()) {
 659                 _exit(0);
 660         }
 661
 662         /* detach from the terminal */
 663 #ifdef HAVE_SETSID
 664         setsid();
 665 #elif defined TIOCNOTTY
 666         i = open("/dev/tty", O_RDWR);
 667         if (i >= 0) {
 668                 ioctl(i, (int)TIOCNOTTY, (char *)0);
 669                 close(i);
 670         }
 671 #endif
 672         /* make sure that stdin, stdout an stderr don't stuff things
 673          * up (library functions, for example) */
 674         for (i = 0; i < 3; i++) {
 675                 close(i);
 676                 open("/dev/null", O_RDWR);
 677         }
 678 }
 679
 680
 681 /**
 682  * This is like socketpair but uses tcp. It is used by the Samba
 683  * regression test code.
 684  *
 685  * The function guarantees that nobody else can attach to the socket,
 686  * or if they do that this function fails and the socket gets closed
 687  * returns 0 on success, -1 on failure the resulting file descriptors
 688  * are symmetrical.
 689  **/
 690 static int socketpair_tcp(int fd[2])
 691 {
 692         int listener;
 693         struct sockaddr_in sock;
 694         struct sockaddr_in sock2;
 695         socklen_t socklen = sizeof sock;
 696         int connect_done = 0;
 697
 698         fd[0] = fd[1] = listener = -1;
 699
 700         memset(&sock, 0, sizeof sock);
 701
 702         if ((listener = socket(PF_INET, SOCK_STREAM, 0)) == -1)
 703                 goto failed;
 704
 705         memset(&sock2, 0, sizeof sock2);
 706 #ifdef HAVE_SOCKADDR_IN_LEN
 707         sock2.sin_len = sizeof sock2;
 708 #endif
 709         sock2.sin_family = PF_INET;
 710
 711         bind(listener, (struct sockaddr *)&sock2, sizeof sock2);
 712
 713         if (listen(listener, 1) != 0)
 714                 goto failed;
 715
 716         if (getsockname(listener, (struct sockaddr *)&sock, &socklen) != 0)
 717                 goto failed;
 718
 719         if ((fd[1] = socket(PF_INET, SOCK_STREAM, 0)) == -1)
 720                 goto failed;
 721
 722         set_nonblocking(fd[1]);
 723
 724         sock.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
 725
 726         if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) == -1) {
 727                 if (errno != EINPROGRESS)
 728                         goto failed;
 729         } else
 730                 connect_done = 1;
 731
 732         if ((fd[0] = accept(listener, (struct sockaddr *)&sock, &socklen)) == -1)
 733                 goto failed;
 734
 735         close(listener);
 736         listener = -1;
 737
 738         set_blocking(fd[1]);
 739
 740         if (connect_done == 0) {
 741                 if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) != 0
 742                     && errno != EISCONN)
 743                         goto failed;
 744         }
 745
 746         /* all OK! */
 747         return 0;
 748
 749  failed:
 750         if (fd[0] != -1)
 751                 close(fd[0]);
 752         if (fd[1] != -1)
 753                 close(fd[1]);
 754         if (listener != -1)
 755                 close(listener);
 756         return -1;
 757 }
 758
 759
 760
 761 /**
 762  * Run a program on a local tcp socket, so that we can talk to it's
 763  * stdin and stdout.  This is used to fake a connection to a daemon
 764  * for testing -- not for the normal case of running SSH.
 765  *
 766  * @return a socket which is attached to a subprocess running
 767  * "prog". stdin and stdout are attached. stderr is left attached to
 768  * the original stderr
 769  **/
 770 int sock_exec(const char *prog)
 771 {
 772         int fd[2];
 773
 774         if (socketpair_tcp(fd) != 0) {
 775                 rsyserr(FERROR, errno, "socketpair_tcp failed");
 776                 return -1;
 777         }
 778         if (verbose >= 2)
 779                 rprintf(FINFO, "Running socket program: \"%s\"\n", prog);
 780         if (fork() == 0) {
 781                 close(fd[0]);
 782                 close(0);
 783                 close(1);
 784                 dup(fd[1]);
 785                 dup(fd[1]);
 786                 exit(system(prog));
 787         }
 788         close(fd[1]);
 789         return fd[0];
 790 }