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) 2002-2008 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 *sockopts;
  54 extern char *config_file;
  55 extern char *logfile_format;
  56 extern char *files_from;
  57 extern char *tmpdir;
  58 extern struct chmod_mode_struct *chmod_modes;
  59 extern struct filter_list_struct daemon_filter_list;
  60 extern char curr_dir[];
  61 #ifdef ICONV_OPTION
  62 extern char *iconv_opt;
  63 extern iconv_t ic_send, ic_recv;
  64 #endif
  65
  66 char *auth_user;
  67 int read_only = 0;
  68 int module_id = -1;
  69 int munge_symlinks = 0;
  70 struct chmod_mode_struct *daemon_chmod_modes;
  71
  72 /* module_dirlen is the length of the module_dir string when in daemon
  73  * mode and module_dir is not "/"; otherwise 0.  (Note that a chroot-
  74  * enabled module can have a non-"/" module_dir these days.) */
  75 char *module_dir = NULL;
  76 unsigned int module_dirlen = 0;
  77
  78 char *full_module_path;
  79
  80 static int rl_nulls = 0;
  81
  82 #ifdef HAVE_SIGACTION
  83 static struct sigaction sigact;
  84 #endif
  85
  86 /**
  87  * Run a client connected to an rsyncd.  The alternative to this
  88  * function for remote-shell connections is do_cmd().
  89  *
  90  * After negotiating which module to use and reading the server's
  91  * motd, this hands over to client_run().  Telling the server the
  92  * module will cause it to chroot/setuid/etc.
  93  *
  94  * Instead of doing a transfer, the client may at this stage instead
  95  * get a listing of remote modules and exit.
  96  *
  97  * @return -1 for error in startup, or the result of client_run().
  98  * Either way, it eventually gets passed to exit_cleanup().
  99  **/
 100 int start_socket_client(char *host, int remote_argc, char *remote_argv[],
 101                         int argc, char *argv[])
 102 {
 103         int fd, ret;
 104         char *p, *user = NULL;
 105
 106         /* This is redundant with code in start_inband_exchange(), but this
 107          * short-circuits a problem in the client before we open a socket,
 108          * and the extra check won't hurt. */
 109         if (**remote_argv == '/') {
 110                 rprintf(FERROR,
 111                         "ERROR: The remote path must start with a module name not a /\n");
 112                 return -1;
 113         }
 114
 115         if ((p = strrchr(host, '@')) != NULL) {
 116                 user = host;
 117                 host = p+1;
 118                 *p = '\0';
 119         }
 120
 121         fd = open_socket_out_wrapped(host, rsync_port, bind_address,
 122                                      default_af_hint);
 123         if (fd == -1)
 124                 exit_cleanup(RERR_SOCKETIO);
 125
 126 #ifdef ICONV_CONST
 127         setup_iconv();
 128 #endif
 129
 130         ret = start_inband_exchange(fd, fd, user, remote_argc, remote_argv);
 131
 132         return ret ? ret : client_run(fd, fd, -1, argc, argv);
 133 }
 134
 135 static int exchange_protocols(int f_in, int f_out, char *buf, size_t bufsiz, int am_client)
 136 {
 137         int remote_sub = -1;
 138 #if SUBPROTOCOL_VERSION != 0
 139         int our_sub = protocol_version < PROTOCOL_VERSION ? 0 : SUBPROTOCOL_VERSION;
 140 #else
 141         int our_sub = 0;
 142 #endif
 143         char *motd;
 144
 145         io_printf(f_out, "@RSYNCD: %d.%d\n", protocol_version, our_sub);
 146
 147         if (!am_client) {
 148                 motd = lp_motd_file();
 149                 if (motd && *motd) {
 150                         FILE *f = fopen(motd,"r");
 151                         while (f && !feof(f)) {
 152                                 int len = fread(buf, 1, bufsiz - 1, f);
 153                                 if (len > 0)
 154                                         write_buf(f_out, buf, len);
 155                         }
 156                         if (f)
 157                                 fclose(f);
 158                         write_sbuf(f_out, "\n");
 159                 }
 160         }
 161
 162         /* This strips the \n. */
 163         if (!read_line_old(f_in, buf, bufsiz)) {
 164                 if (am_client)
 165                         rprintf(FERROR, "rsync: did not see server greeting\n");
 166                 return -1;
 167         }
 168
 169         if (sscanf(buf, "@RSYNCD: %d.%d", &remote_protocol, &remote_sub) < 1) {
 170                 if (am_client)
 171                         rprintf(FERROR, "rsync: server sent \"%s\" rather than greeting\n", buf);
 172                 else
 173                         io_printf(f_out, "@ERROR: protocol startup error\n");
 174                 return -1;
 175         }
 176
 177         if (remote_sub < 0) {
 178                 if (remote_protocol == 30) {
 179                         if (am_client)
 180                                 rprintf(FERROR, "rsync: server is speaking an incompatible beta of protocol 30\n");
 181                         else
 182                                 io_printf(f_out, "@ERROR: your client is speaking an incompatible beta of protocol 30\n");
 183                         return -1;
 184                 }
 185                 remote_sub = 0;
 186         }
 187
 188         if (protocol_version > remote_protocol) {
 189                 protocol_version = remote_protocol;
 190                 if (remote_sub)
 191                         protocol_version--;
 192         } else if (protocol_version == remote_protocol) {
 193                 if (remote_sub != our_sub)
 194                         protocol_version--;
 195         }
 196 #if SUBPROTOCOL_VERSION != 0
 197         else if (protocol_version < remote_protocol) {
 198                 if (our_sub)
 199                         protocol_version--;
 200         }
 201 #endif
 202
 203         if (protocol_version >= 30)
 204                 rl_nulls = 1;
 205
 206         return 0;
 207 }
 208
 209 int start_inband_exchange(int f_in, int f_out, const char *user, int argc, char *argv[])
 210 {
 211         int i, modlen;
 212         char line[BIGPATHBUFLEN];
 213         char *sargs[MAX_ARGS];
 214         int sargc = 0;
 215         char *p, *modname;
 216
 217         assert(argc > 0 && *argv != NULL);
 218
 219         if (**argv == '/') {
 220                 rprintf(FERROR,
 221                         "ERROR: The remote path must start with a module name\n");
 222                 return -1;
 223         }
 224
 225         if (!(p = strchr(*argv, '/')))
 226                 modlen = strlen(*argv);
 227         else
 228                 modlen = p - *argv;
 229
 230         if (!(modname = new_array(char, modlen+1+1))) /* room for '/' & '\0' */
 231                 out_of_memory("start_inband_exchange");
 232         strlcpy(modname, *argv, modlen + 1);
 233         modname[modlen] = '/';
 234         modname[modlen+1] = '\0';
 235
 236         if (!user)
 237                 user = getenv("USER");
 238         if (!user)
 239                 user = getenv("LOGNAME");
 240
 241         if (exchange_protocols(f_in, f_out, line, sizeof line, 1) < 0)
 242                 return -1;
 243
 244         /* set daemon_over_rsh to false since we need to build the
 245          * true set of args passed through the rsh/ssh connection;
 246          * this is a no-op for direct-socket-connection mode */
 247         daemon_over_rsh = 0;
 248         server_options(sargs, &sargc);
 249
 250         if (sargc >= MAX_ARGS - 2)
 251                 goto arg_overflow;
 252
 253         sargs[sargc++] = ".";
 254
 255         while (argc > 0) {
 256                 if (sargc >= MAX_ARGS - 1) {
 257                   arg_overflow:
 258                         rprintf(FERROR, "internal: args[] overflowed in do_cmd()\n");
 259                         exit_cleanup(RERR_SYNTAX);
 260                 }
 261                 if (strncmp(*argv, modname, modlen) == 0
 262                  && argv[0][modlen] == '\0')
 263                         sargs[sargc++] = modname; /* we send "modname/" */
 264                 else
 265                         sargs[sargc++] = *argv;
 266                 argv++;
 267                 argc--;
 268         }
 269
 270         sargs[sargc] = NULL;
 271
 272         if (verbose > 1)
 273                 print_child_argv("sending daemon args:", sargs);
 274
 275         io_printf(f_out, "%.*s\n", modlen, modname);
 276
 277         /* Old servers may just drop the connection here,
 278          rather than sending a proper EXIT command.  Yuck. */
 279         kluge_around_eof = list_only && protocol_version < 25 ? 1 : 0;
 280
 281         while (1) {
 282                 if (!read_line_old(f_in, line, sizeof line)) {
 283                         rprintf(FERROR, "rsync: didn't get server startup line\n");
 284                         return -1;
 285                 }
 286
 287                 if (strncmp(line,"@RSYNCD: AUTHREQD ",18) == 0) {
 288                         auth_client(f_out, user, line+18);
 289                         continue;
 290                 }
 291
 292                 if (strcmp(line,"@RSYNCD: OK") == 0)
 293                         break;
 294
 295                 if (strcmp(line,"@RSYNCD: EXIT") == 0) {
 296                         /* This is sent by recent versions of the
 297                          * server to terminate the listing of modules.
 298                          * We don't want to go on and transfer
 299                          * anything; just exit. */
 300                         exit(0);
 301                 }
 302
 303                 if (strncmp(line, "@ERROR", 6) == 0) {
 304                         rprintf(FERROR, "%s\n", line);
 305                         /* This is always fatal; the server will now
 306                          * close the socket. */
 307                         return -1;
 308                 }
 309
 310                 /* This might be a MOTD line or a module listing, but there is
 311                  * no way to differentiate it.  The manpage mentions this. */
 312                 if (output_motd)
 313                         rprintf(FINFO, "%s\n", line);
 314         }
 315         kluge_around_eof = 0;
 316
 317         if (rl_nulls) {
 318                 for (i = 0; i < sargc; i++) {
 319                         if (!sargs[i]) /* stop at --protect-args NULL */
 320                                 break;
 321                         write_sbuf(f_out, sargs[i]);
 322                         write_byte(f_out, 0);
 323                 }
 324                 write_byte(f_out, 0);
 325         } else {
 326                 for (i = 0; i < sargc; i++)
 327                         io_printf(f_out, "%s\n", sargs[i]);
 328                 write_sbuf(f_out, "\n");
 329         }
 330
 331         if (protect_args)
 332                 send_protected_args(f_out, sargs);
 333
 334         if (protocol_version < 23) {
 335                 if (protocol_version == 22 || !am_sender)
 336                         io_start_multiplex_in();
 337         }
 338
 339         free(modname);
 340
 341         return 0;
 342 }
 343
 344 static char *finish_pre_exec(pid_t pid, int fd, char *request,
 345                              char **early_argv, char **argv)
 346 {
 347         int j = 0, status = -1;
 348
 349         if (!request)
 350                 request = "(NONE)";
 351
 352         write_buf(fd, request, strlen(request)+1);
 353         if (early_argv) {
 354                 for ( ; *early_argv; early_argv++)
 355                         write_buf(fd, *early_argv, strlen(*early_argv)+1);
 356                 j = 1; /* Skip arg0 name in argv. */
 357         }
 358         for ( ; argv[j]; j++) {
 359                 write_buf(fd, argv[j], strlen(argv[j])+1);
 360                 if (argv[j][0] == '.' && argv[j][1] == '\0')
 361                         break;
 362         }
 363         write_byte(fd, 0);
 364
 365         close(fd);
 366
 367         if (wait_process(pid, &status, 0) < 0
 368          || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 369                 char *e;
 370                 if (asprintf(&e, "pre-xfer exec returned failure (%d)%s%s\n",
 371                              status, status < 0 ? ": " : "",
 372                              status < 0 ? strerror(errno) : "") < 0)
 373                         out_of_memory("finish_pre_exec");
 374                 return e;
 375         }
 376         return NULL;
 377 }
 378
 379 static int read_arg_from_pipe(int fd, char *buf, int limit)
 380 {
 381         char *bp = buf, *eob = buf + limit - 1;
 382
 383         while (1) {
 384             int got = read(fd, bp, 1);
 385             if (got != 1) {
 386                 if (got < 0 && errno == EINTR)
 387                         continue;
 388                 return -1;
 389             }
 390             if (*bp == '\0')
 391                 break;
 392             if (bp < eob)
 393                 bp++;
 394         }
 395         *bp = '\0';
 396
 397         return bp - buf;
 398 }
 399
 400 static int path_failure(int f_out, const char *dir, BOOL was_chdir)
 401 {
 402         if (was_chdir)
 403                 rsyserr(FLOG, errno, "chdir %s failed\n", dir);
 404         else
 405                 rprintf(FLOG, "normalize_path(%s) failed\n", dir);
 406         io_printf(f_out, "@ERROR: chdir failed\n");
 407         return -1;
 408 }
 409
 410 static int rsync_module(int f_in, int f_out, int i, char *addr, char *host)
 411 {
 412         int argc;
 413         char **argv, **orig_argv, **orig_early_argv, *module_chdir;
 414         char line[BIGPATHBUFLEN];
 415         uid_t uid = (uid_t)-2;  /* canonically "nobody" */
 416         gid_t gid = (gid_t)-2;
 417         char *p, *err_msg = NULL;
 418         char *name = lp_name(i);
 419         int use_chroot = lp_use_chroot(i);
 420         int ret, pre_exec_fd = -1;
 421         pid_t pre_exec_pid = 0;
 422         char *request = NULL;
 423
 424 #ifdef ICONV_OPTION
 425         iconv_opt = lp_charset(i);
 426         if (*iconv_opt)
 427                 setup_iconv();
 428         iconv_opt = NULL;
 429 #endif
 430
 431         if (!allow_access(addr, host, lp_hosts_allow(i), lp_hosts_deny(i))) {
 432                 rprintf(FLOG, "rsync denied on module %s from %s (%s)\n",
 433                         name, host, addr);
 434                 if (!lp_list(i))
 435                         io_printf(f_out, "@ERROR: Unknown module '%s'\n", name);
 436                 else {
 437                         io_printf(f_out,
 438                                   "@ERROR: access denied to %s from %s (%s)\n",
 439                                   name, host, addr);
 440                 }
 441                 return -1;
 442         }
 443
 444         if (am_daemon && am_server) {
 445                 rprintf(FLOG, "rsync allowed access on module %s from %s (%s)\n",
 446                         name, host, addr);
 447         }
 448
 449         if (!claim_connection(lp_lock_file(i), lp_max_connections(i))) {
 450                 if (errno) {
 451                         rsyserr(FLOG, errno, "failed to open lock file %s",
 452                                 lp_lock_file(i));
 453                         io_printf(f_out, "@ERROR: failed to open lock file\n");
 454                 } else {
 455                         rprintf(FLOG, "max connections (%d) reached\n",
 456                                 lp_max_connections(i));
 457                         io_printf(f_out, "@ERROR: max connections (%d) reached -- try again later\n",
 458                                 lp_max_connections(i));
 459                 }
 460                 return -1;
 461         }
 462
 463         auth_user = auth_server(f_in, f_out, i, host, addr, "@RSYNCD: AUTHREQD ");
 464
 465         if (!auth_user) {
 466                 io_printf(f_out, "@ERROR: auth failed on module %s\n", name);
 467                 return -1;
 468         }
 469
 470         module_id = i;
 471
 472         if (lp_read_only(i))
 473                 read_only = 1;
 474
 475         if (lp_transfer_logging(i) && !logfile_format)
 476                 logfile_format = lp_log_format(i);
 477         if (log_format_has(logfile_format, 'i'))
 478                 logfile_format_has_i = 1;
 479         if (logfile_format_has_i || log_format_has(logfile_format, 'o'))
 480                 logfile_format_has_o_or_i = 1;
 481
 482         am_root = (MY_UID() == 0);
 483
 484         if (am_root) {
 485                 p = lp_uid(i);
 486                 if (!name_to_uid(p, &uid)) {
 487                         if (!isDigit(p)) {
 488                                 rprintf(FLOG, "Invalid uid %s\n", p);
 489                                 io_printf(f_out, "@ERROR: invalid uid %s\n", p);
 490                                 return -1;
 491                         }
 492                         uid = atoi(p);
 493                 }
 494
 495                 p = lp_gid(i);
 496                 if (!name_to_gid(p, &gid)) {
 497                         if (!isDigit(p)) {
 498                                 rprintf(FLOG, "Invalid gid %s\n", p);
 499                                 io_printf(f_out, "@ERROR: invalid gid %s\n", p);
 500                                 return -1;
 501                         }
 502                         gid = atoi(p);
 503                 }
 504         }
 505
 506         /* TODO: If we're not root, but the configuration requests
 507          * that we change to some uid other than the current one, then
 508          * log a warning. */
 509
 510         /* TODO: Perhaps take a list of gids, and make them into the
 511          * supplementary groups. */
 512
 513         module_dir = lp_path(i);
 514         if (use_chroot) {
 515                 if ((p = strstr(module_dir, "/./")) != NULL) {
 516                         *p = '\0'; /* Temporary... */
 517                         if (!(module_chdir = normalize_path(module_dir, True, NULL)))
 518                                 return path_failure(f_out, module_dir, False);
 519                         *p = '/';
 520                         if (!(p = normalize_path(p + 2, True, &module_dirlen)))
 521                                 return path_failure(f_out, strstr(module_dir, "/./"), False);
 522                         if (!(full_module_path = normalize_path(module_dir, False, NULL)))
 523                                 full_module_path = module_dir;
 524                         module_dir = p;
 525                 } else {
 526                         if (!(module_chdir = normalize_path(module_dir, False, NULL)))
 527                                 return path_failure(f_out, module_dir, False);
 528                         full_module_path = module_chdir;
 529                         module_dir = "/";
 530                         module_dirlen = 1;
 531                 }
 532         } else {
 533                 if (!(module_chdir = normalize_path(module_dir, False, &module_dirlen)))
 534                         return path_failure(f_out, module_dir, False);
 535                 full_module_path = module_dir = module_chdir;
 536         }
 537
 538         if (module_dirlen == 1) {
 539                 module_dirlen = 0;
 540                 set_filter_dir("/", 1);
 541         } else
 542                 set_filter_dir(module_dir, module_dirlen);
 543
 544         p = lp_filter(i);
 545         parse_rule(&daemon_filter_list, p, MATCHFLG_WORD_SPLIT,
 546                    XFLG_ABS_IF_SLASH | XFLG_DIR2WILD3);
 547
 548         p = lp_include_from(i);
 549         parse_filter_file(&daemon_filter_list, p, MATCHFLG_INCLUDE,
 550             XFLG_ABS_IF_SLASH | XFLG_DIR2WILD3 | XFLG_OLD_PREFIXES | XFLG_FATAL_ERRORS);
 551
 552         p = lp_include(i);
 553         parse_rule(&daemon_filter_list, p,
 554                    MATCHFLG_INCLUDE | MATCHFLG_WORD_SPLIT,
 555                    XFLG_ABS_IF_SLASH | XFLG_DIR2WILD3 | XFLG_OLD_PREFIXES);
 556
 557         p = lp_exclude_from(i);
 558         parse_filter_file(&daemon_filter_list, p, 0,
 559             XFLG_ABS_IF_SLASH | XFLG_DIR2WILD3 | XFLG_OLD_PREFIXES | XFLG_FATAL_ERRORS);
 560
 561         p = lp_exclude(i);
 562         parse_rule(&daemon_filter_list, p, MATCHFLG_WORD_SPLIT,
 563                    XFLG_ABS_IF_SLASH | XFLG_DIR2WILD3 | XFLG_OLD_PREFIXES);
 564
 565         log_init(1);
 566
 567 #ifdef HAVE_PUTENV
 568         if (*lp_prexfer_exec(i) || *lp_postxfer_exec(i)) {
 569                 char *modname, *modpath, *hostaddr, *hostname, *username;
 570                 int status;
 571
 572                 if (asprintf(&modname, "RSYNC_MODULE_NAME=%s", name) < 0
 573                  || asprintf(&modpath, "RSYNC_MODULE_PATH=%s", full_module_path) < 0
 574                  || asprintf(&hostaddr, "RSYNC_HOST_ADDR=%s", addr) < 0
 575                  || asprintf(&hostname, "RSYNC_HOST_NAME=%s", host) < 0
 576                  || asprintf(&username, "RSYNC_USER_NAME=%s", auth_user) < 0)
 577                         out_of_memory("rsync_module");
 578                 putenv(modname);
 579                 putenv(modpath);
 580                 putenv(hostaddr);
 581                 putenv(hostname);
 582                 putenv(username);
 583                 umask(orig_umask);
 584                 /* For post-xfer exec, fork a new process to run the rsync
 585                  * daemon while this process waits for the exit status and
 586                  * runs the indicated command at that point. */
 587                 if (*lp_postxfer_exec(i)) {
 588                         pid_t pid = fork();
 589                         if (pid < 0) {
 590                                 rsyserr(FLOG, errno, "fork failed");
 591                                 io_printf(f_out, "@ERROR: fork failed\n");
 592                                 return -1;
 593                         }
 594                         if (pid) {
 595                                 if (asprintf(&p, "RSYNC_PID=%ld", (long)pid) > 0)
 596                                         putenv(p);
 597                                 if (wait_process(pid, &status, 0) < 0)
 598                                         status = -1;
 599                                 if (asprintf(&p, "RSYNC_RAW_STATUS=%d", status) > 0)
 600                                         putenv(p);
 601                                 if (WIFEXITED(status))
 602                                         status = WEXITSTATUS(status);
 603                                 else
 604                                         status = -1;
 605                                 if (asprintf(&p, "RSYNC_EXIT_STATUS=%d", status) > 0)
 606                                         putenv(p);
 607                                 if (system(lp_postxfer_exec(i)) < 0)
 608                                         status = -1;
 609                                 _exit(status);
 610                         }
 611                 }
 612                 /* For pre-xfer exec, fork a child process to run the indicated
 613                  * command, though it first waits for the parent process to
 614                  * send us the user's request via a pipe. */
 615                 if (*lp_prexfer_exec(i)) {
 616                         int fds[2];
 617                         if (asprintf(&p, "RSYNC_PID=%ld", (long)getpid()) > 0)
 618                                 putenv(p);
 619                         if (pipe(fds) < 0 || (pre_exec_pid = fork()) < 0) {
 620                                 rsyserr(FLOG, errno, "pre-xfer exec preparation failed");
 621                                 io_printf(f_out, "@ERROR: pre-xfer exec preparation failed\n");
 622                                 return -1;
 623                         }
 624                         if (pre_exec_pid == 0) {
 625                                 char buf[BIGPATHBUFLEN];
 626                                 int j, len;
 627                                 close(fds[1]);
 628                                 set_blocking(fds[0]);
 629                                 len = read_arg_from_pipe(fds[0], buf, BIGPATHBUFLEN);
 630                                 if (len <= 0)
 631                                         _exit(1);
 632                                 if (asprintf(&p, "RSYNC_REQUEST=%s", buf) > 0)
 633                                         putenv(p);
 634                                 for (j = 0; ; j++) {
 635                                         len = read_arg_from_pipe(fds[0], buf,
 636                                                                  BIGPATHBUFLEN);
 637                                         if (len <= 0) {
 638                                                 if (!len)
 639                                                         break;
 640                                                 _exit(1);
 641                                         }
 642                                         if (asprintf(&p, "RSYNC_ARG%d=%s", j, buf) > 0)
 643                                                 putenv(p);
 644                                 }
 645                                 close(fds[0]);
 646                                 close(STDIN_FILENO);
 647                                 close(STDOUT_FILENO);
 648                                 status = system(lp_prexfer_exec(i));
 649                                 if (!WIFEXITED(status))
 650                                         _exit(1);
 651                                 _exit(WEXITSTATUS(status));
 652                         }
 653                         close(fds[0]);
 654                         set_blocking(fds[1]);
 655                         pre_exec_fd = fds[1];
 656                 }
 657                 umask(0);
 658         }
 659 #endif
 660
 661         if (use_chroot) {
 662                 /*
 663                  * XXX: The 'use chroot' flag is a fairly reliable
 664                  * source of confusion, because it fails under two
 665                  * important circumstances: running as non-root,
 666                  * running on Win32 (or possibly others).  On the
 667                  * other hand, if you are running as root, then it
 668                  * might be better to always use chroot.
 669                  *
 670                  * So, perhaps if we can't chroot we should just issue
 671                  * a warning, unless a "require chroot" flag is set,
 672                  * in which case we fail.
 673                  */
 674                 if (chroot(module_chdir)) {
 675                         rsyserr(FLOG, errno, "chroot %s failed", module_chdir);
 676                         io_printf(f_out, "@ERROR: chroot failed\n");
 677                         return -1;
 678                 }
 679                 module_chdir = module_dir;
 680         }
 681
 682         if (!change_dir(module_chdir, CD_NORMAL))
 683                 return path_failure(f_out, module_chdir, True);
 684         if (module_dirlen || !use_chroot)
 685                 sanitize_paths = 1;
 686
 687         if ((munge_symlinks = lp_munge_symlinks(i)) < 0)
 688                 munge_symlinks = !use_chroot || module_dirlen;
 689         if (munge_symlinks) {
 690                 STRUCT_STAT st;
 691                 if (do_stat(SYMLINK_PREFIX, &st) == 0 && S_ISDIR(st.st_mode)) {
 692                         rprintf(FLOG, "Symlink munging is unsupported when a %s directory exists.\n",
 693                                 SYMLINK_PREFIX);
 694                         io_printf(f_out, "@ERROR: daemon security issue -- contact admin\n", name);
 695                         exit_cleanup(RERR_UNSUPPORTED);
 696                 }
 697         }
 698
 699         if (am_root) {
 700                 /* XXXX: You could argue that if the daemon is started
 701                  * by a non-root user and they explicitly specify a
 702                  * gid, then we should try to change to that gid --
 703                  * this could be possible if it's already in their
 704                  * supplementary groups. */
 705
 706                 /* TODO: Perhaps we need to document that if rsyncd is
 707                  * started by somebody other than root it will inherit
 708                  * all their supplementary groups. */
 709
 710                 if (setgid(gid)) {
 711                         rsyserr(FLOG, errno, "setgid %d failed", (int)gid);
 712                         io_printf(f_out, "@ERROR: setgid failed\n");
 713                         return -1;
 714                 }
 715 #ifdef HAVE_SETGROUPS
 716                 /* Get rid of any supplementary groups this process
 717                  * might have inheristed. */
 718                 if (setgroups(1, &gid)) {
 719                         rsyserr(FLOG, errno, "setgroups failed");
 720                         io_printf(f_out, "@ERROR: setgroups failed\n");
 721                         return -1;
 722                 }
 723 #endif
 724
 725                 if (setuid(uid)) {
 726                         rsyserr(FLOG, errno, "setuid %d failed", (int)uid);
 727                         io_printf(f_out, "@ERROR: setuid failed\n");
 728                         return -1;
 729                 }
 730
 731                 am_root = (MY_UID() == 0);
 732         }
 733
 734         if (lp_temp_dir(i) && *lp_temp_dir(i)) {
 735                 tmpdir = lp_temp_dir(i);
 736                 if (strlen(tmpdir) >= MAXPATHLEN - 10) {
 737                         rprintf(FLOG,
 738                                 "the 'temp dir' value for %s is WAY too long -- ignoring.\n",
 739                                 name);
 740                         tmpdir = NULL;
 741                 }
 742         }
 743
 744         io_printf(f_out, "@RSYNCD: OK\n");
 745
 746         read_args(f_in, name, line, sizeof line, rl_nulls, &argv, &argc, &request);
 747         orig_argv = argv;
 748
 749         verbose = 0; /* future verbosity is controlled by client options */
 750         ret = parse_arguments(&argc, (const char ***) &argv);
 751         if (protect_args && ret) {
 752                 orig_early_argv = orig_argv;
 753                 protect_args = 2;
 754                 read_args(f_in, name, line, sizeof line, 1, &argv, &argc, &request);
 755                 orig_argv = argv;
 756                 ret = parse_arguments(&argc, (const char ***) &argv);
 757         } else
 758                 orig_early_argv = NULL;
 759
 760         if (pre_exec_pid) {
 761                 err_msg = finish_pre_exec(pre_exec_pid, pre_exec_fd, request,
 762                                           orig_early_argv, orig_argv);
 763         }
 764
 765         if (orig_early_argv)
 766                 free(orig_early_argv);
 767
 768         am_server = 1; /* Don't let someone try to be tricky. */
 769         quiet = 0;
 770         if (lp_ignore_errors(module_id))
 771                 ignore_errors = 1;
 772         if (write_batch < 0)
 773                 dry_run = 1;
 774
 775         if (lp_fake_super(i)) {
 776                 if (preserve_xattrs > 1)
 777                         preserve_xattrs = 1;
 778                 am_root = -1;
 779         } else if (am_root < 0) /* Treat --fake-super from client as --super. */
 780                 am_root = 2;
 781
 782         if (filesfrom_fd == 0)
 783                 filesfrom_fd = f_in;
 784
 785         if (request) {
 786                 if (*auth_user) {
 787                         rprintf(FLOG, "rsync %s %s from %s@%s (%s)\n",
 788                                 am_sender ? "on" : "to",
 789                                 request, auth_user, host, addr);
 790                 } else {
 791                         rprintf(FLOG, "rsync %s %s from %s (%s)\n",
 792                                 am_sender ? "on" : "to",
 793                                 request, host, addr);
 794                 }
 795                 free(request);
 796         }
 797
 798 #ifndef DEBUG
 799         /* don't allow the logs to be flooded too fast */
 800         if (verbose > lp_max_verbosity(i))
 801                 verbose = lp_max_verbosity(i);
 802 #endif
 803
 804         if (protocol_version < 23
 805             && (protocol_version == 22 || am_sender))
 806                 io_start_multiplex_out();
 807         else if (!ret || err_msg) {
 808                 /* We have to get I/O multiplexing started so that we can
 809                  * get the error back to the client.  This means getting
 810                  * the protocol setup finished first in later versions. */
 811                 setup_protocol(f_out, f_in);
 812                 if (!am_sender) {
 813                         /* Since we failed in our option parsing, we may not
 814                          * have finished parsing that the client sent us a
 815                          * --files-from option, so look for it manually.
 816                          * Without this, the socket would be in the wrong
 817                          * state for the upcoming error message. */
 818                         if (!files_from) {
 819                                 int i;
 820                                 for (i = 0; i < argc; i++) {
 821                                         if (strncmp(argv[i], "--files-from", 12) == 0) {
 822                                                 files_from = "";
 823                                                 break;
 824                                         }
 825                                 }
 826                         }
 827                         if (files_from)
 828                                 write_byte(f_out, 0);
 829                 }
 830                 io_start_multiplex_out();
 831         }
 832
 833         if (!ret || err_msg) {
 834                 if (err_msg)
 835                         rwrite(FERROR, err_msg, strlen(err_msg), 0);
 836                 else
 837                         option_error();
 838                 msleep(400);
 839                 exit_cleanup(RERR_UNSUPPORTED);
 840         }
 841
 842 #ifdef ICONV_OPTION
 843         if (!iconv_opt) {
 844                 if (ic_send != (iconv_t)-1) {
 845                         iconv_close(ic_send);
 846                         ic_send = (iconv_t)-1;
 847                 }
 848                 if (ic_recv != (iconv_t)-1) {
 849                         iconv_close(ic_recv);
 850                         ic_recv = (iconv_t)-1;
 851                 }
 852         }
 853 #endif
 854
 855         if (!numeric_ids
 856          && (use_chroot ? lp_numeric_ids(i) != False : lp_numeric_ids(i) == True))
 857                 numeric_ids = -1; /* Set --numeric-ids w/o breaking protocol. */
 858
 859         if (lp_timeout(i) && lp_timeout(i) > io_timeout)
 860                 set_io_timeout(lp_timeout(i));
 861
 862         /* If we have some incoming/outgoing chmod changes, append them to
 863          * any user-specified changes (making our changes have priority).
 864          * We also get a pointer to just our changes so that a receiver
 865          * process can use them separately if --perms wasn't specified. */
 866         if (am_sender)
 867                 p = lp_outgoing_chmod(i);
 868         else
 869                 p = lp_incoming_chmod(i);
 870         if (*p && !(daemon_chmod_modes = parse_chmod(p, &chmod_modes))) {
 871                 rprintf(FLOG, "Invalid \"%sing chmod\" directive: %s\n",
 872                         am_sender ? "outgo" : "incom", p);
 873         }
 874
 875         start_server(f_in, f_out, argc, argv);
 876
 877         return 0;
 878 }
 879
 880 /* send a list of available modules to the client. Don't list those
 881    with "list = False". */
 882 static void send_listing(int fd)
 883 {
 884         int n = lp_numservices();
 885         int i;
 886
 887         for (i = 0; i < n; i++) {
 888                 if (lp_list(i))
 889                         io_printf(fd, "%-15s\t%s\n", lp_name(i), lp_comment(i));
 890         }
 891
 892         if (protocol_version >= 25)
 893                 io_printf(fd,"@RSYNCD: EXIT\n");
 894 }
 895
 896 static int load_config(int globals_only)
 897 {
 898         if (!config_file) {
 899                 if (am_server && am_root <= 0)
 900                         config_file = RSYNCD_USERCONF;
 901                 else
 902                         config_file = RSYNCD_SYSCONF;
 903         }
 904         return lp_load(config_file, globals_only);
 905 }
 906
 907 /* this is called when a connection is established to a client
 908    and we want to start talking. The setup of the system is done from
 909    here */
 910 int start_daemon(int f_in, int f_out)
 911 {
 912         char line[1024];
 913         char *addr, *host;
 914         int i;
 915
 916         io_set_sock_fds(f_in, f_out);
 917
 918         /* We must load the config file before calling any function that
 919          * might cause log-file output to occur.  This ensures that the
 920          * "log file" param gets honored for the 2 non-forked use-cases
 921          * (when rsync is run by init and run by a remote shell). */
 922         if (!load_config(0))
 923                 exit_cleanup(RERR_SYNTAX);
 924
 925         addr = client_addr(f_in);
 926         host = client_name(f_in);
 927         rprintf(FLOG, "connect from %s (%s)\n", host, addr);
 928
 929         if (!am_server) {
 930                 set_socket_options(f_in, "SO_KEEPALIVE");
 931                 set_nonblocking(f_in);
 932         }
 933
 934         if (exchange_protocols(f_in, f_out, line, sizeof line, 0) < 0)
 935                 return -1;
 936
 937         line[0] = 0;
 938         if (!read_line_old(f_in, line, sizeof line))
 939                 return -1;
 940
 941         if (!*line || strcmp(line, "#list") == 0) {
 942                 rprintf(FLOG, "module-list request from %s (%s)\n",
 943                         host, addr);
 944                 send_listing(f_out);
 945                 return -1;
 946         }
 947
 948         if (*line == '#') {
 949                 /* it's some sort of command that I don't understand */
 950                 io_printf(f_out, "@ERROR: Unknown command '%s'\n", line);
 951                 return -1;
 952         }
 953
 954         if ((i = lp_number(line)) < 0) {
 955                 rprintf(FLOG, "unknown module '%s' tried from %s (%s)\n",
 956                         line, host, addr);
 957                 io_printf(f_out, "@ERROR: Unknown module '%s'\n", line);
 958                 return -1;
 959         }
 960
 961 #ifdef HAVE_SIGACTION
 962         sigact.sa_flags = SA_NOCLDSTOP;
 963 #endif
 964         SIGACTION(SIGCHLD, remember_children);
 965
 966         return rsync_module(f_in, f_out, i, addr, host);
 967 }
 968
 969 static void create_pid_file(void)
 970 {
 971         char *pid_file = lp_pid_file();
 972         char pidbuf[16];
 973         pid_t pid = getpid();
 974         int fd, len;
 975
 976         if (!pid_file || !*pid_file)
 977                 return;
 978
 979         cleanup_set_pid(pid);
 980         if ((fd = do_open(pid_file, O_WRONLY|O_CREAT|O_EXCL, 0666 & ~orig_umask)) == -1) {
 981           failure:
 982                 cleanup_set_pid(0);
 983                 fprintf(stderr, "failed to create pid file %s: %s\n", pid_file, strerror(errno));
 984                 rsyserr(FLOG, errno, "failed to create pid file %s", pid_file);
 985                 exit_cleanup(RERR_FILEIO);
 986         }
 987         snprintf(pidbuf, sizeof pidbuf, "%ld\n", (long)pid);
 988         len = strlen(pidbuf);
 989         if (write(fd, pidbuf, len) != len)
 990                 goto failure;
 991         close(fd);
 992 }
 993
 994 /* Become a daemon, discarding the controlling terminal. */
 995 static void become_daemon(void)
 996 {
 997         int i;
 998         pid_t pid = fork();
 999
1000         if (pid) {
1001                 if (pid < 0) {
1002                         fprintf(stderr, "failed to fork: %s\n", strerror(errno));
1003                         exit_cleanup(RERR_FILEIO);
1004                 }
1005                 _exit(0);
1006         }
1007
1008         create_pid_file();
1009
1010         /* detach from the terminal */
1011 #ifdef HAVE_SETSID
1012         setsid();
1013 #elif defined TIOCNOTTY
1014         i = open("/dev/tty", O_RDWR);
1015         if (i >= 0) {
1016                 ioctl(i, (int)TIOCNOTTY, (char *)0);
1017                 close(i);
1018         }
1019 #endif
1020         /* make sure that stdin, stdout an stderr don't stuff things
1021          * up (library functions, for example) */
1022         for (i = 0; i < 3; i++) {
1023                 close(i);
1024                 open("/dev/null", O_RDWR);
1025         }
1026 }
1027
1028 int daemon_main(void)
1029 {
1030         if (is_a_socket(STDIN_FILENO)) {
1031                 int i;
1032
1033                 /* we are running via inetd - close off stdout and
1034                  * stderr so that library functions (and getopt) don't
1035                  * try to use them. Redirect them to /dev/null */
1036                 for (i = 1; i < 3; i++) {
1037                         close(i);
1038                         open("/dev/null", O_RDWR);
1039                 }
1040
1041                 return start_daemon(STDIN_FILENO, STDIN_FILENO);
1042         }
1043
1044         if (!load_config(1)) {
1045                 fprintf(stderr, "Failed to parse config file: %s\n", config_file);
1046                 exit_cleanup(RERR_SYNTAX);
1047         }
1048
1049         if (no_detach)
1050                 create_pid_file();
1051         else
1052                 become_daemon();
1053
1054         if (rsync_port == 0 && (rsync_port = lp_rsync_port()) == 0)
1055                 rsync_port = RSYNC_PORT;
1056         if (bind_address == NULL && *lp_bind_address())
1057                 bind_address = lp_bind_address();
1058
1059         log_init(0);
1060
1061         rprintf(FLOG, "rsyncd version %s starting, listening on port %d\n",
1062                 RSYNC_VERSION, rsync_port);
1063         /* TODO: If listening on a particular address, then show that
1064          * address too.  In fact, why not just do inet_ntop on the
1065          * local address??? */
1066
1067         start_accept_loop(rsync_port, start_daemon);
1068         return -1;
1069 }