clientserver.c

   1 /*
   2  * The socket based protocol for setting up a connection with rsyncd.
   3  *
   4  * Copyright (C) 1998-2001 Andrew Tridgell <tridge@samba.org>
   5  * Copyright (C) 2001-2002 Martin Pool <mbp@samba.org>
   6  * Copyright (C) 2002-2009 Wayne Davison
   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 3 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 along
  19  * with this program; if not, visit the http://fsf.org website.
  20  */
  21
  22 #include "rsync.h"
  23 #include "ifuncs.h"
  24
  25 extern int quiet;
  26 extern int verbose;
  27 extern int dry_run;
  28 extern int output_motd;
  29 extern int list_only;
  30 extern int am_sender;
  31 extern int am_server;
  32 extern int am_daemon;
  33 extern int am_root;
  34 extern int rsync_port;
  35 extern int protect_args;
  36 extern int ignore_errors;
  37 extern int preserve_xattrs;
  38 extern int kluge_around_eof;
  39 extern int daemon_over_rsh;
  40 extern int sanitize_paths;
  41 extern int numeric_ids;
  42 extern int filesfrom_fd;
  43 extern int remote_protocol;
  44 extern int protocol_version;
  45 extern int io_timeout;
  46 extern int no_detach;
  47 extern int write_batch;
  48 extern int default_af_hint;
  49 extern int logfile_format_has_i;
  50 extern int logfile_format_has_o_or_i;
  51 extern mode_t orig_umask;
  52 extern char *bind_address;
  53 extern char *config_file;
  54 extern char *logfile_format;
  55 extern char *files_from;
  56 extern char *tmpdir;
  57 extern struct chmod_mode_struct *chmod_modes;
  58 extern struct filter_list_struct daemon_filter_list;
  59 #ifdef ICONV_OPTION
  60 extern char *iconv_opt;
  61 extern iconv_t ic_send, ic_recv;
  62 #endif
  63
  64 char *auth_user;
  65 int read_only = 0;
  66 int module_id = -1;
  67 int munge_symlinks = 0;
  68 struct chmod_mode_struct *daemon_chmod_modes;
  69
  70 /* module_dirlen is the length of the module_dir string when in daemon
  71  * mode and module_dir is not "/"; otherwise 0.  (Note that a chroot-
  72  * enabled module can have a non-"/" module_dir these days.) */
  73 char *module_dir = NULL;
  74 unsigned int module_dirlen = 0;
  75
  76 char *full_module_path;
  77
  78 static int rl_nulls = 0;
  79
  80 #ifdef HAVE_SIGACTION
  81 static struct sigaction sigact;
  82 #endif
  83
  84 /**
  85  * Run a client connected to an rsyncd.  The alternative to this
  86  * function for remote-shell connections is do_cmd().
  87  *
  88  * After negotiating which module to use and reading the server's
  89  * motd, this hands over to client_run().  Telling the server the
  90  * module will cause it to chroot/setuid/etc.
  91  *
  92  * Instead of doing a transfer, the client may at this stage instead
  93  * get a listing of remote modules and exit.
  94  *
  95  * @return -1 for error in startup, or the result of client_run().
  96  * Either way, it eventually gets passed to exit_cleanup().
  97  **/
  98 int start_socket_client(char *host, int remote_argc, char *remote_argv[],
  99                         int argc, char *argv[])
 100 {
 101         int fd, ret;
 102         char *p, *user = NULL;
 103
 104         /* This is redundant with code in start_inband_exchange(), but this
 105          * short-circuits a problem in the client before we open a socket,
 106          * and the extra check won't hurt. */
 107         if (**remote_argv == '/') {
 108                 rprintf(FERROR,
 109                         "ERROR: The remote path must start with a module name not a /\n");
 110                 return -1;
 111         }
 112
 113         if ((p = strrchr(host, '@')) != NULL) {
 114                 user = host;
 115                 host = p+1;
 116                 *p = '\0';
 117         }
 118
 119         fd = open_socket_out_wrapped(host, rsync_port, bind_address,
 120                                      default_af_hint);
 121         if (fd == -1)
 122                 exit_cleanup(RERR_SOCKETIO);
 123
 124 #ifdef ICONV_CONST
 125         setup_iconv();
 126 #endif
 127
 128         ret = start_inband_exchange(fd, fd, user, remote_argc, remote_argv);
 129
 130         return ret ? ret : client_run(fd, fd, -1, argc, argv);
 131 }
 132
 133 static int exchange_protocols(int f_in, int f_out, char *buf, size_t bufsiz, int am_client)
 134 {
 135         int remote_sub = -1;
 136 #if SUBPROTOCOL_VERSION != 0
 137         int our_sub = protocol_version < PROTOCOL_VERSION ? 0 : SUBPROTOCOL_VERSION;
 138 #else
 139         int our_sub = 0;
 140 #endif
 141         char *motd;
 142
 143         io_printf(f_out, "@RSYNCD: %d.%d\n", protocol_version, our_sub);
 144
 145         if (!am_client) {
 146                 motd = lp_motd_file();
 147                 if (motd && *motd) {
 148                         FILE *f = fopen(motd,"r");
 149                         while (f && !feof(f)) {
 150                                 int len = fread(buf, 1, bufsiz - 1, f);
 151                                 if (len > 0)
 152                                         write_buf(f_out, buf, len);
 153                         }
 154                         if (f)
 155                                 fclose(f);
 156                         write_sbuf(f_out, "\n");
 157                 }
 158         }
 159
 160         /* This strips the \n. */
 161         if (!read_line_old(f_in, buf, bufsiz)) {
 162                 if (am_client)
 163                         rprintf(FERROR, "rsync: did not see server greeting\n");
 164                 return -1;
 165         }
 166
 167         if (sscanf(buf, "@RSYNCD: %d.%d", &remote_protocol, &remote_sub) < 1) {
 168                 if (am_client)
 169                         rprintf(FERROR, "rsync: server sent \"%s\" rather than greeting\n", buf);
 170                 else
 171                         io_printf(f_out, "@ERROR: protocol startup error\n");
 172                 return -1;
 173         }
 174
 175         if (remote_sub < 0) {
 176                 if (remote_protocol == 30) {
 177                         if (am_client)
 178                                 rprintf(FERROR, "rsync: server is speaking an incompatible beta of protocol 30\n");
 179                         else
 180                                 io_printf(f_out, "@ERROR: your client is speaking an incompatible beta of protocol 30\n");
 181                         return -1;
 182                 }
 183                 remote_sub = 0;
 184         }
 185
 186         if (protocol_version > remote_protocol) {
 187                 protocol_version = remote_protocol;
 188                 if (remote_sub)
 189                         protocol_version--;
 190         } else if (protocol_version == remote_protocol) {
 191                 if (remote_sub != our_sub)
 192                         protocol_version--;
 193         }
 194 #if SUBPROTOCOL_VERSION != 0
 195         else if (protocol_version < remote_protocol) {
 196                 if (our_sub)
 197                         protocol_version--;
 198         }
 199 #endif
 200
 201         if (protocol_version >= 30)
 202                 rl_nulls = 1;
 203
 204         return 0;
 205 }
 206
 207 int start_inband_exchange(int f_in, int f_out, const char *user, int argc, char *argv[])
 208 {
 209         int i, modlen;
 210         char line[BIGPATHBUFLEN];
 211         char *sargs[MAX_ARGS];
 212         int sargc = 0;
 213         char *p, *modname;
 214
 215         assert(argc > 0 && *argv != NULL);
 216
 217         if (**argv == '/') {
 218                 rprintf(FERROR,
 219                         "ERROR: The remote path must start with a module name\n");
 220                 return -1;
 221         }
 222
 223         if (!(p = strchr(*argv, '/')))
 224                 modlen = strlen(*argv);
 225         else
 226                 modlen = p - *argv;
 227
 228         if (!(modname = new_array(char, modlen+1+1))) /* room for '/' & '\0' */
 229                 out_of_memory("start_inband_exchange");
 230         strlcpy(modname, *argv, modlen + 1);
 231         modname[modlen] = '/';
 232         modname[modlen+1] = '\0';
 233
 234         if (!user)
 235                 user = getenv("USER");
 236         if (!user)
 237                 user = getenv("LOGNAME");
 238
 239         if (exchange_protocols(f_in, f_out, line, sizeof line, 1) < 0)
 240                 return -1;
 241
 242         /* set daemon_over_rsh to false since we need to build the
 243          * true set of args passed through the rsh/ssh connection;
 244          * this is a no-op for direct-socket-connection mode */
 245         daemon_over_rsh = 0;
 246         server_options(sargs, &sargc);
 247
 248         if (sargc >= MAX_ARGS - 2)
 249                 goto arg_overflow;
 250
 251         sargs[sargc++] = ".";
 252
 253         while (argc > 0) {
 254                 if (sargc >= MAX_ARGS - 1) {
 255                   arg_overflow:
 256                         rprintf(FERROR, "internal: args[] overflowed in do_cmd()\n");
 257                         exit_cleanup(RERR_SYNTAX);
 258                 }
 259                 if (strncmp(*argv, modname, modlen) == 0
 260                  && argv[0][modlen] == '\0')
 261                         sargs[sargc++] = modname; /* we send "modname/" */
 262                 else if (**argv == '-') {
 263                         if (asprintf(sargs + sargc++, "./%s", *argv) < 0)
 264                                 out_of_memory("start_inband_exchange");
 265                 } else
 266                         sargs[sargc++] = *argv;
 267                 argv++;
 268                 argc--;
 269         }
 270
 271         sargs[sargc] = NULL;
 272
 273         if (verbose > 1)
 274                 print_child_argv("sending daemon args:", sargs);
 275
 276         io_printf(f_out, "%.*s\n", modlen, modname);
 277
 278         /* Old servers may just drop the connection here,
 279          rather than sending a proper EXIT command.  Yuck. */
 280         kluge_around_eof = list_only && protocol_version < 25 ? 1 : 0;
 281
 282         while (1) {
 283                 if (!read_line_old(f_in, line, sizeof line)) {
 284                         rprintf(FERROR, "rsync: didn't get server startup line\n");
 285                         return -1;
 286                 }
 287
 288                 if (strncmp(line,"@RSYNCD: AUTHREQD ",18) == 0) {
 289                         auth_client(f_out, user, line+18);
 290                         continue;
 291                 }
 292
 293                 if (strcmp(line,"@RSYNCD: OK") == 0)
 294                         break;
 295
 296                 if (strcmp(line,"@RSYNCD: EXIT") == 0) {
 297                         /* This is sent by recent versions of the
 298                          * server to terminate the listing of modules.
 299                          * We don't want to go on and transfer
 300                          * anything; just exit. */
 301                         exit(0);
 302                 }
 303
 304                 if (strncmp(line, "@ERROR", 6) == 0) {
 305                         rprintf(FERROR, "%s\n", line);
 306                         /* This is always fatal; the server will now
 307                          * close the socket. */
 308                         return -1;
 309                 }
 310
 311                 /* This might be a MOTD line or a module listing, but there is
 312                  * no way to differentiate it.  The manpage mentions this. */
 313                 if (output_motd)
 314                         rprintf(FINFO, "%s\n", line);
 315         }
 316         kluge_around_eof = 0;
 317
 318         if (rl_nulls) {
 319                 for (i = 0; i < sargc; i++) {
 320                         if (!sargs[i]) /* stop at --protect-args NULL */
 321                                 break;
 322                         write_sbuf(f_out, sargs[i]);
 323                         write_byte(f_out, 0);
 324                 }
 325                 write_byte(f_out, 0);
 326         } else {
 327                 for (i = 0; i < sargc; i++)
 328                         io_printf(f_out, "%s\n", sargs[i]);
 329                 write_sbuf(f_out, "\n");
 330         }
 331
 332         if (protect_args)
 333                 send_protected_args(f_out, sargs);
 334
 335         if (protocol_version < 23) {
 336                 if (protocol_version == 22 || !am_sender)
 337                         io_start_multiplex_in();
 338         }
 339
 340         free(modname);
 341
 342         return 0;
 343 }
 344
 345 static char *finish_pre_exec(pid_t pid, int fd, char *request,
 346                              char **early_argv, char **argv)
 347 {
 348         int j = 0, status = -1;
 349
 350         if (!request)
 351                 request = "(NONE)";
 352
 353         write_buf(fd, request, strlen(request)+1);
 354         if (early_argv) {
 355                 for ( ; *early_argv; early_argv++)
 356                         write_buf(fd, *early_argv, strlen(*early_argv)+1);
 357                 j = 1; /* Skip arg0 name in argv. */
 358         }
 359         for ( ; argv[j]; j++) {
 360                 write_buf(fd, argv[j], strlen(argv[j])+1);
 361                 if (argv[j][0] == '.' && argv[j][1] == '\0')
 362                         break;
 363         }
 364         write_byte(fd, 0);
 365
 366         close(fd);
 367
 368         if (wait_process(pid, &status, 0) < 0
 369          || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 370                 char *e;
 371                 if (asprintf(&e, "pre-xfer exec returned failure (%d)%s%s\n",
 372                              status, status < 0 ? ": " : "",
 373                              status < 0 ? strerror(errno) : "") < 0)
 374                         out_of_memory("finish_pre_exec");
 375                 return e;
 376         }
 377         return NULL;
 378 }
 379
 380 static int read_arg_from_pipe(int fd, char *buf, int limit)
 381 {
 382         char *bp = buf, *eob = buf + limit - 1;
 383
 384         while (1) {
 385             int got = read(fd, bp, 1);
 386             if (got != 1) {
 387                 if (got < 0 && errno == EINTR)
 388                         continue;
 389                 return -1;
 390             }
 391             if (*bp == '\0')
 392                 break;
 393             if (bp < eob)
 394                 bp++;
 395         }
 396         *bp = '\0';
 397
 398         return bp - buf;
 399 }
 400
 401 static int path_failure(int f_out, const char *dir, BOOL was_chdir)
 402 {
 403         if (was_chdir)
 404                 rsyserr(FLOG, errno, "chdir %s failed\n", dir);
 405         else
 406                 rprintf(FLOG, "normalize_path(%s) failed\n", dir);
 407         io_printf(f_out, "@ERROR: chdir failed\n");
 408         return -1;
 409 }
 410
 411 static int rsync_module(int f_in, int f_out, int i, char *addr, char *host)
 412 {
 413         int argc;
 414         char **argv, **orig_argv, **orig_early_argv, *module_chdir;
 415         char line[BIGPATHBUFLEN];
 416         uid_t uid = (uid_t)-2;  /* canonically "nobody" */
 417         gid_t gid = (gid_t)-2;
 418         char *p, *err_msg = NULL;
 419         char *name = lp_name(i);
 420         int use_chroot = lp_use_chroot(i);
 421         int ret, pre_exec_fd = -1;
 422         pid_t pre_exec_pid = 0;
 423         char *request = NULL;
 424
 425 #ifdef ICONV_OPTION
 426         iconv_opt = lp_charset(i);
 427         if (*iconv_opt)
 428                 setup_iconv();
 429         iconv_opt = NULL;
 430 #endif
 431
 432         if (!allow_access(addr, host, lp_hosts_allow(i), lp_hosts_deny(i))) {
 433                 rprintf(FLOG, "rsync denied on module %s from %s (%s)\n",
 434                         name, host, addr);
 435                 if (!lp_list(i))
 436                         io_printf(f_out, "@ERROR: Unknown module '%s'\n", name);
 437                 else {
 438                         io_printf(f_out,
 439                                   "@ERROR: access denied to %s from %s (%s)\n",
 440                                   name, host, addr);
 441                 }
 442                 return -1;
 443         }
 444
 445         if (am_daemon && am_server) {
 446                 rprintf(FLOG, "rsync allowed access on module %s from %s (%s)\n",
 447                         name, host, addr);
 448         }
 449
 450         if (!claim_connection(lp_lock_file(i), lp_max_connections(i))) {
 451                 if (errno) {
 452                         rsyserr(FLOG, errno, "failed to open lock file %s",
 453                                 lp_lock_file(i));
 454                         io_printf(f_out, "@ERROR: failed to open lock file\n");
 455                 } else {
 456                         rprintf(FLOG, "max connections (%d) reached\n",
 457                                 lp_max_connections(i));
 458                         io_printf(f_out, "@ERROR: max connections (%d) reached -- try again later\n",
 459                                 lp_max_connections(i));
 460                 }
 461                 return -1;
 462         }
 463
 464         auth_user = auth_server(f_in, f_out, i, host, addr, "@RSYNCD: AUTHREQD ");
 465
 466         if (!auth_user) {
 467                 io_printf(f_out, "@ERROR: auth failed on module %s\n", name);
 468                 return -1;
 469         }
 470
 471         module_id = i;
 472
 473         if (lp_read_only(i))
 474                 read_only = 1;
 475
 476         if (lp_transfer_logging(i) && !logfile_format)
 477                 logfile_format = lp_log_format(i);
 478         if (log_format_has(logfile_format, 'i'))
 479                 logfile_format_has_i = 1;
 480         if (logfile_format_has_i || log_format_has(logfile_format, 'o'))
 481                 logfile_format_has_o_or_i = 1;
 482
 483         am_root = (MY_UID() == 0);
 484
 485         if (am_root) {
 486                 p = lp_uid(i);
 487                 if (!name_to_uid(p, &uid)) {
 488                         if (!isDigit(p)) {
 489                                 rprintf(FLOG, "Invalid uid %s\n", p);
 490                                 io_printf(f_out, "@ERROR: invalid uid %s\n", p);
 491                                 return -1;
 492                         }
 493                         uid = atoi(p);
 494                 }
 495
 496                 p = lp_gid(i);
 497                 if (!name_to_gid(p, &gid)) {
 498                         if (!isDigit(p)) {
 499                                 rprintf(FLOG, "Invalid gid %s\n", p);
 500                                 io_printf(f_out, "@ERROR: invalid gid %s\n", p);
 501                                 return -1;
 502                         }
 503                         gid = atoi(p);
 504                 }
 505         }
 506
 507         /* TODO: If we're not root, but the configuration requests
 508          * that we change to some uid other than the current one, then
 509          * log a warning. */
 510
 511         /* TODO: Perhaps take a list of gids, and make them into the
 512          * supplementary groups. */
 513
 514         module_dir = lp_path(i);
 515         if (*module_dir == '\0') {
 516                 rprintf(FLOG, "No path specified for module %s\n", name);
 517                 io_printf(f_out, "@ERROR: no path setting.\n");
 518                 return -1;
 519         }
 520         if (use_chroot) {
 521                 if ((p = strstr(module_dir, "/./")) != NULL) {
 522                         *p = '\0'; /* Temporary... */
 523                         if (!(module_chdir = normalize_path(module_dir, True, NULL)))
 524                                 return path_failure(f_out, module_dir, False);
 525                         *p = '/';
 526                         if (!(p = normalize_path(p + 2, True, &module_dirlen)))
 527                                 return path_failure(f_out, strstr(module_dir, "/./"), False);
 528                         if (!(full_module_path = normalize_path(module_dir, False, NULL)))
 529                                 full_module_path = module_dir;
 530                         module_dir = p;
 531                 } else {
 532                         if (!(module_chdir = normalize_path(module_dir, False, NULL)))
 533                                 return path_failure(f_out, module_dir, False);
 534                         full_module_path = module_chdir;
 535                         module_dir = "/";
 536                         module_dirlen = 1;
 537                 }
 538         } else {
 539                 if (!(module_chdir = normalize_path(module_dir, False, &module_dirlen)))
 540                         return path_failure(f_out, module_dir, False);
 541                 full_module_path = module_dir = module_chdir;
 542         }
 543
 544         if (module_dirlen == 1) {
 545                 module_dirlen = 0;
 546                 set_filter_dir("/", 1);
 547         } else
 548                 set_filter_dir(module_dir, module_dirlen);
 549
 550         p = lp_filter(i);
 551         parse_rule(&daemon_filter_list, p, MATCHFLG_WORD_SPLIT,
 552                    XFLG_ABS_IF_SLASH | XFLG_DIR2WILD3);
 553
 554         p = lp_include_from(i);
 555         parse_filter_file(&daemon_filter_list, p, MATCHFLG_INCLUDE,
 556             XFLG_ABS_IF_SLASH | XFLG_DIR2WILD3 | XFLG_OLD_PREFIXES | XFLG_FATAL_ERRORS);
 557
 558         p = lp_include(i);
 559         parse_rule(&daemon_filter_list, p,
 560                    MATCHFLG_INCLUDE | MATCHFLG_WORD_SPLIT,
 561                    XFLG_ABS_IF_SLASH | XFLG_DIR2WILD3 | XFLG_OLD_PREFIXES);
 562
 563         p = lp_exclude_from(i);
 564         parse_filter_file(&daemon_filter_list, p, 0,
 565             XFLG_ABS_IF_SLASH | XFLG_DIR2WILD3 | XFLG_OLD_PREFIXES | XFLG_FATAL_ERRORS);
 566
 567         p = lp_exclude(i);
 568         parse_rule(&daemon_filter_list, p, MATCHFLG_WORD_SPLIT,
 569                    XFLG_ABS_IF_SLASH | XFLG_DIR2WILD3 | XFLG_OLD_PREFIXES);
 570
 571         log_init(1);
 572
 573 #ifdef HAVE_PUTENV
 574         if (*lp_prexfer_exec(i) || *lp_postxfer_exec(i)) {
 575                 char *modname, *modpath, *hostaddr, *hostname, *username;
 576                 int status;
 577
 578                 if (asprintf(&modname, "RSYNC_MODULE_NAME=%s", name) < 0
 579                  || asprintf(&modpath, "RSYNC_MODULE_PATH=%s", full_module_path) < 0
 580                  || asprintf(&hostaddr, "RSYNC_HOST_ADDR=%s", addr) < 0
 581                  || asprintf(&hostname, "RSYNC_HOST_NAME=%s", host) < 0
 582                  || asprintf(&username, "RSYNC_USER_NAME=%s", auth_user) < 0)
 583                         out_of_memory("rsync_module");
 584                 putenv(modname);
 585                 putenv(modpath);
 586                 putenv(hostaddr);
 587                 putenv(hostname);
 588                 putenv(username);
 589                 umask(orig_umask);
 590                 /* For post-xfer exec, fork a new process to run the rsync
 591                  * daemon while this process waits for the exit status and
 592                  * runs the indicated command at that point. */
 593                 if (*lp_postxfer_exec(i)) {
 594                         pid_t pid = fork();
 595                         if (pid < 0) {
 596                                 rsyserr(FLOG, errno, "fork failed");
 597                                 io_printf(f_out, "@ERROR: fork failed\n");
 598                                 return -1;
 599                         }
 600                         if (pid) {
 601                                 if (asprintf(&p, "RSYNC_PID=%ld", (long)pid) > 0)
 602                                         putenv(p);
 603                                 if (wait_process(pid, &status, 0) < 0)
 604                                         status = -1;
 605                                 if (asprintf(&p, "RSYNC_RAW_STATUS=%d", status) > 0)
 606                                         putenv(p);
 607                                 if (WIFEXITED(status))
 608                                         status = WEXITSTATUS(status);
 609                                 else
 610                                         status = -1;
 611                                 if (asprintf(&p, "RSYNC_EXIT_STATUS=%d", status) > 0)
 612                                         putenv(p);
 613                                 if (system(lp_postxfer_exec(i)) < 0)
 614                                         status = -1;
 615                                 _exit(status);
 616                         }
 617                 }
 618                 /* For pre-xfer exec, fork a child process to run the indicated
 619                  * command, though it first waits for the parent process to
 620                  * send us the user's request via a pipe. */
 621                 if (*lp_prexfer_exec(i)) {
 622                         int fds[2];
 623                         if (asprintf(&p, "RSYNC_PID=%ld", (long)getpid()) > 0)
 624                                 putenv(p);
 625                         if (pipe(fds) < 0 || (pre_exec_pid = fork()) < 0) {
 626                                 rsyserr(FLOG, errno, "pre-xfer exec preparation failed");
 627                                 io_printf(f_out, "@ERROR: pre-xfer exec preparation failed\n");
 628                                 return -1;
 629                         }
 630                         if (pre_exec_pid == 0) {
 631                                 char buf[BIGPATHBUFLEN];
 632                                 int j, len;
 633                                 close(fds[1]);
 634                                 set_blocking(fds[0]);
 635                                 len = read_arg_from_pipe(fds[0], buf, BIGPATHBUFLEN);
 636                                 if (len <= 0)
 637                                         _exit(1);
 638                                 if (asprintf(&p, "RSYNC_REQUEST=%s", buf) > 0)
 639                                         putenv(p);
 640                                 for (j = 0; ; j++) {
 641                                         len = read_arg_from_pipe(fds[0], buf,
 642                                                                  BIGPATHBUFLEN);
 643                                         if (len <= 0) {
 644                                                 if (!len)
 645                                                         break;
 646                                                 _exit(1);
 647                                         }
 648                                         if (asprintf(&p, "RSYNC_ARG%d=%s", j, buf) > 0)
 649                                                 putenv(p);
 650                                 }
 651                                 close(fds[0]);
 652                                 close(STDIN_FILENO);
 653                                 close(STDOUT_FILENO);
 654                                 status = system(lp_prexfer_exec(i));
 655                                 if (!WIFEXITED(status))
 656                                         _exit(1);
 657                                 _exit(WEXITSTATUS(status));
 658                         }
 659                         close(fds[0]);
 660                         set_blocking(fds[1]);
 661                         pre_exec_fd = fds[1];
 662                 }
 663                 umask(0);
 664         }
 665 #endif
 666
 667         if (use_chroot) {
 668                 /*
 669                  * XXX: The 'use chroot' flag is a fairly reliable
 670                  * source of confusion, because it fails under two
 671                  * important circumstances: running as non-root,
 672                  * running on Win32 (or possibly others).  On the
 673                  * other hand, if you are running as root, then it
 674                  * might be better to always use chroot.
 675                  *
 676                  * So, perhaps if we can't chroot we should just issue
 677                  * a warning, unless a "require chroot" flag is set,
 678                  * in which case we fail.
 679                  */
 680                 if (chroot(module_chdir)) {
 681                         rsyserr(FLOG, errno, "chroot %s failed", module_chdir);
 682                         io_printf(f_out, "@ERROR: chroot failed\n");
 683                         return -1;
 684                 }
 685                 module_chdir = module_dir;
 686         }
 687
 688         if (!change_dir(module_chdir, CD_NORMAL))
 689                 return path_failure(f_out, module_chdir, True);
 690         if (module_dirlen || !use_chroot)
 691                 sanitize_paths = 1;
 692
 693         if ((munge_symlinks = lp_munge_symlinks(i)) < 0)
 694                 munge_symlinks = !use_chroot || module_dirlen;
 695         if (munge_symlinks) {
 696                 STRUCT_STAT st;
 697                 if (do_stat(SYMLINK_PREFIX, &st) == 0 && S_ISDIR(st.st_mode)) {
 698                         rprintf(FLOG, "Symlink munging is unsupported when a %s directory exists.\n",
 699                                 SYMLINK_PREFIX);
 700                         io_printf(f_out, "@ERROR: daemon security issue -- contact admin\n", name);
 701                         exit_cleanup(RERR_UNSUPPORTED);
 702                 }
 703         }
 704
 705         if (am_root) {
 706                 /* XXXX: You could argue that if the daemon is started
 707                  * by a non-root user and they explicitly specify a
 708                  * gid, then we should try to change to that gid --
 709                  * this could be possible if it's already in their
 710                  * supplementary groups. */
 711
 712                 /* TODO: Perhaps we need to document that if rsyncd is
 713                  * started by somebody other than root it will inherit
 714                  * all their supplementary groups. */
 715
 716                 if (setgid(gid)) {
 717                         rsyserr(FLOG, errno, "setgid %d failed", (int)gid);
 718                         io_printf(f_out, "@ERROR: setgid failed\n");
 719                         return -1;
 720                 }
 721 #ifdef HAVE_SETGROUPS
 722                 /* Get rid of any supplementary groups this process
 723                  * might have inheristed. */
 724                 if (setgroups(1, &gid)) {
 725                         rsyserr(FLOG, errno, "setgroups failed");
 726                         io_printf(f_out, "@ERROR: setgroups failed\n");
 727                         return -1;
 728                 }
 729 #endif
 730
 731                 if (setuid(uid) < 0
 732 #ifdef HAVE_SETEUID
 733                  || seteuid(uid) < 0
 734 #endif
 735                 ) {
 736                         rsyserr(FLOG, errno, "setuid %d failed", (int)uid);
 737                         io_printf(f_out, "@ERROR: setuid failed\n");
 738                         return -1;
 739                 }
 740
 741                 am_root = (MY_UID() == 0);
 742         }
 743
 744         if (lp_temp_dir(i) && *lp_temp_dir(i)) {
 745                 tmpdir = lp_temp_dir(i);
 746                 if (strlen(tmpdir) >= MAXPATHLEN - 10) {
 747                         rprintf(FLOG,
 748                                 "the 'temp dir' value for %s is WAY too long -- ignoring.\n",
 749                                 name);
 750                         tmpdir = NULL;
 751                 }
 752         }
 753
 754         io_printf(f_out, "@RSYNCD: OK\n");
 755
 756         read_args(f_in, name, line, sizeof line, rl_nulls, &argv, &argc, &request);
 757         orig_argv = argv;
 758
 759         verbose = 0; /* future verbosity is controlled by client options */
 760         ret = parse_arguments(&argc, (const char ***) &argv);
 761         if (protect_args && ret) {
 762                 orig_early_argv = orig_argv;
 763                 protect_args = 2;
 764                 read_args(f_in, name, line, sizeof line, 1, &argv, &argc, &request);
 765                 orig_argv = argv;
 766                 ret = parse_arguments(&argc, (const char ***) &argv);
 767         } else
 768                 orig_early_argv = NULL;
 769
 770         if (pre_exec_pid) {
 771                 err_msg = finish_pre_exec(pre_exec_pid, pre_exec_fd, request,
 772                                           orig_early_argv, orig_argv);
 773         }
 774
 775         if (orig_early_argv)
 776                 free(orig_early_argv);
 777
 778         am_server = 1; /* Don't let someone try to be tricky. */
 779         quiet = 0;
 780         if (lp_ignore_errors(module_id))
 781                 ignore_errors = 1;
 782         if (write_batch < 0)
 783                 dry_run = 1;
 784
 785         if (lp_fake_super(i)) {
 786                 if (preserve_xattrs > 1)
 787                         preserve_xattrs = 1;
 788                 am_root = -1;
 789         } else if (am_root < 0) /* Treat --fake-super from client as --super. */
 790                 am_root = 2;
 791
 792         if (filesfrom_fd == 0)
 793                 filesfrom_fd = f_in;
 794
 795         if (request) {
 796                 if (*auth_user) {
 797                         rprintf(FLOG, "rsync %s %s from %s@%s (%s)\n",
 798                                 am_sender ? "on" : "to",
 799                                 request, auth_user, host, addr);
 800                 } else {
 801                         rprintf(FLOG, "rsync %s %s from %s (%s)\n",
 802                                 am_sender ? "on" : "to",
 803                                 request, host, addr);
 804                 }
 805                 free(request);
 806         }
 807
 808 #ifndef DEBUG
 809         /* don't allow the logs to be flooded too fast */
 810         if (verbose > lp_max_verbosity(i))
 811                 verbose = lp_max_verbosity(i);
 812 #endif
 813
 814         if (protocol_version < 23
 815             && (protocol_version == 22 || am_sender))
 816                 io_start_multiplex_out();
 817         else if (!ret || err_msg) {
 818                 /* We have to get I/O multiplexing started so that we can
 819                  * get the error back to the client.  This means getting
 820                  * the protocol setup finished first in later versions. */
 821                 setup_protocol(f_out, f_in);
 822                 if (!am_sender) {
 823                         /* Since we failed in our option parsing, we may not
 824                          * have finished parsing that the client sent us a
 825                          * --files-from option, so look for it manually.
 826                          * Without this, the socket would be in the wrong
 827                          * state for the upcoming error message. */
 828                         if (!files_from) {
 829                                 int i;
 830                                 for (i = 0; i < argc; i++) {
 831                                         if (strncmp(argv[i], "--files-from", 12) == 0) {
 832                                                 files_from = "";
 833                                                 break;
 834                                         }
 835                                 }
 836                         }
 837                         if (files_from)
 838                                 write_byte(f_out, 0);
 839                 }
 840                 io_start_multiplex_out();
 841         }
 842
 843         if (!ret || err_msg) {
 844                 if (err_msg)
 845                         rwrite(FERROR, err_msg, strlen(err_msg), 0);
 846                 else
 847                         option_error();
 848                 msleep(400);
 849                 exit_cleanup(RERR_UNSUPPORTED);
 850         }
 851
 852 #ifdef ICONV_OPTION
 853         if (!iconv_opt) {
 854                 if (ic_send != (iconv_t)-1) {
 855                         iconv_close(ic_send);
 856                         ic_send = (iconv_t)-1;
 857                 }
 858                 if (ic_recv != (iconv_t)-1) {
 859                         iconv_close(ic_recv);
 860                         ic_recv = (iconv_t)-1;
 861                 }
 862         }
 863 #endif
 864
 865         if (!numeric_ids
 866          && (use_chroot ? lp_numeric_ids(i) != False : lp_numeric_ids(i) == True))
 867                 numeric_ids = -1; /* Set --numeric-ids w/o breaking protocol. */
 868
 869         if (lp_timeout(i) && (!io_timeout || lp_timeout(i) < io_timeout))
 870                 set_io_timeout(lp_timeout(i));
 871
 872         /* If we have some incoming/outgoing chmod changes, append them to
 873          * any user-specified changes (making our changes have priority).
 874          * We also get a pointer to just our changes so that a receiver
 875          * process can use them separately if --perms wasn't specified. */
 876         if (am_sender)
 877                 p = lp_outgoing_chmod(i);
 878         else
 879                 p = lp_incoming_chmod(i);
 880         if (*p && !(daemon_chmod_modes = parse_chmod(p, &chmod_modes))) {
 881                 rprintf(FLOG, "Invalid \"%sing chmod\" directive: %s\n",
 882                         am_sender ? "outgo" : "incom", p);
 883         }
 884
 885         start_server(f_in, f_out, argc, argv);
 886
 887         return 0;
 888 }
 889
 890 /* send a list of available modules to the client. Don't list those
 891    with "list = False". */
 892 static void send_listing(int fd)
 893 {
 894         int n = lp_numservices();
 895         int i;
 896
 897         for (i = 0; i < n; i++) {
 898                 if (lp_list(i))
 899                         io_printf(fd, "%-15s\t%s\n", lp_name(i), lp_comment(i));
 900         }
 901
 902         if (protocol_version >= 25)
 903                 io_printf(fd,"@RSYNCD: EXIT\n");
 904 }
 905
 906 static int load_config(int globals_only)
 907 {
 908         if (!config_file) {
 909                 if (am_server && am_root <= 0)
 910                         config_file = RSYNCD_USERCONF;
 911                 else
 912                         config_file = RSYNCD_SYSCONF;
 913         }
 914         return lp_load(config_file, globals_only);
 915 }
 916
 917 /* this is called when a connection is established to a client
 918    and we want to start talking. The setup of the system is done from
 919    here */
 920 int start_daemon(int f_in, int f_out)
 921 {
 922         char line[1024];
 923         char *addr, *host;
 924         int i;
 925
 926         io_set_sock_fds(f_in, f_out);
 927
 928         /* We must load the config file before calling any function that
 929          * might cause log-file output to occur.  This ensures that the
 930          * "log file" param gets honored for the 2 non-forked use-cases
 931          * (when rsync is run by init and run by a remote shell). */
 932         if (!load_config(0))
 933                 exit_cleanup(RERR_SYNTAX);
 934
 935         addr = client_addr(f_in);
 936         host = client_name(f_in);
 937         rprintf(FLOG, "connect from %s (%s)\n", host, addr);
 938
 939         if (!am_server) {
 940                 set_socket_options(f_in, "SO_KEEPALIVE");
 941                 set_nonblocking(f_in);
 942         }
 943
 944         if (exchange_protocols(f_in, f_out, line, sizeof line, 0) < 0)
 945                 return -1;
 946
 947         line[0] = 0;
 948         if (!read_line_old(f_in, line, sizeof line))
 949                 return -1;
 950
 951         if (!*line || strcmp(line, "#list") == 0) {
 952                 rprintf(FLOG, "module-list request from %s (%s)\n",
 953                         host, addr);
 954                 send_listing(f_out);
 955                 return -1;
 956         }
 957
 958         if (*line == '#') {
 959                 /* it's some sort of command that I don't understand */
 960                 io_printf(f_out, "@ERROR: Unknown command '%s'\n", line);
 961                 return -1;
 962         }
 963
 964         if ((i = lp_number(line)) < 0) {
 965                 rprintf(FLOG, "unknown module '%s' tried from %s (%s)\n",
 966                         line, host, addr);
 967                 io_printf(f_out, "@ERROR: Unknown module '%s'\n", line);
 968                 return -1;
 969         }
 970
 971 #ifdef HAVE_SIGACTION
 972         sigact.sa_flags = SA_NOCLDSTOP;
 973 #endif
 974         SIGACTION(SIGCHLD, remember_children);
 975
 976         return rsync_module(f_in, f_out, i, addr, host);
 977 }
 978
 979 static void create_pid_file(void)
 980 {
 981         char *pid_file = lp_pid_file();
 982         char pidbuf[16];
 983         pid_t pid = getpid();
 984         int fd, len;
 985
 986         if (!pid_file || !*pid_file)
 987                 return;
 988
 989         cleanup_set_pid(pid);
 990         if ((fd = do_open(pid_file, O_WRONLY|O_CREAT|O_EXCL, 0666 & ~orig_umask)) == -1) {
 991           failure:
 992                 cleanup_set_pid(0);
 993                 fprintf(stderr, "failed to create pid file %s: %s\n", pid_file, strerror(errno));
 994                 rsyserr(FLOG, errno, "failed to create pid file %s", pid_file);
 995                 exit_cleanup(RERR_FILEIO);
 996         }
 997         snprintf(pidbuf, sizeof pidbuf, "%ld\n", (long)pid);
 998         len = strlen(pidbuf);
 999         if (write(fd, pidbuf, len) != len)
1000                 goto failure;
1001         close(fd);
1002 }
1003
1004 /* Become a daemon, discarding the controlling terminal. */
1005 static void become_daemon(void)
1006 {
1007         int i;
1008         pid_t pid = fork();
1009
1010         if (pid) {
1011                 if (pid < 0) {
1012                         fprintf(stderr, "failed to fork: %s\n", strerror(errno));
1013                         exit_cleanup(RERR_FILEIO);
1014                 }
1015                 _exit(0);
1016         }
1017
1018         create_pid_file();
1019
1020         /* detach from the terminal */
1021 #ifdef HAVE_SETSID
1022         setsid();
1023 #elif defined TIOCNOTTY
1024         i = open("/dev/tty", O_RDWR);
1025         if (i >= 0) {
1026                 ioctl(i, (int)TIOCNOTTY, (char *)0);
1027                 close(i);
1028         }
1029 #endif
1030         /* make sure that stdin, stdout an stderr don't stuff things
1031          * up (library functions, for example) */
1032         for (i = 0; i < 3; i++) {
1033                 close(i);
1034                 open("/dev/null", O_RDWR);
1035         }
1036 }
1037
1038 int daemon_main(void)
1039 {
1040         if (is_a_socket(STDIN_FILENO)) {
1041                 int i;
1042
1043                 /* we are running via inetd - close off stdout and
1044                  * stderr so that library functions (and getopt) don't
1045                  * try to use them. Redirect them to /dev/null */
1046                 for (i = 1; i < 3; i++) {
1047                         close(i);
1048                         open("/dev/null", O_RDWR);
1049                 }
1050
1051                 return start_daemon(STDIN_FILENO, STDIN_FILENO);
1052         }
1053
1054         if (!load_config(1)) {
1055                 fprintf(stderr, "Failed to parse config file: %s\n", config_file);
1056                 exit_cleanup(RERR_SYNTAX);
1057         }
1058
1059         if (no_detach)
1060                 create_pid_file();
1061         else
1062                 become_daemon();
1063
1064         if (rsync_port == 0 && (rsync_port = lp_rsync_port()) == 0)
1065                 rsync_port = RSYNC_PORT;
1066         if (bind_address == NULL && *lp_bind_address())
1067                 bind_address = lp_bind_address();
1068
1069         log_init(0);
1070
1071         rprintf(FLOG, "rsyncd version %s starting, listening on port %d\n",
1072                 RSYNC_VERSION, rsync_port);
1073         /* TODO: If listening on a particular address, then show that
1074          * address too.  In fact, why not just do inet_ntop on the
1075          * local address??? */
1076
1077         start_accept_loop(rsync_port, start_daemon);
1078         return -1;
1079 }