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) 2002-2007 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 verbose;
  26 extern int output_motd;
  27 extern int list_only;
  28 extern int am_sender;
  29 extern int am_server;
  30 extern int am_daemon;
  31 extern int am_root;
  32 extern int rsync_port;
  33 extern int ignore_errors;
  34 extern int kluge_around_eof;
  35 extern int daemon_over_rsh;
  36 extern int sanitize_paths;
  37 extern int filesfrom_fd;
  38 extern int remote_protocol;
  39 extern int protocol_version;
  40 extern int io_timeout;
  41 extern int no_detach;
  42 extern int default_af_hint;
  43 extern int logfile_format_has_i;
  44 extern int logfile_format_has_o_or_i;
  45 extern mode_t orig_umask;
  46 extern char *bind_address;
  47 extern char *sockopts;
  48 extern char *config_file;
  49 extern char *logfile_format;
  50 extern char *files_from;
  51 extern char *tmpdir;
  52 extern struct chmod_mode_struct *chmod_modes;
  53 extern struct filter_list_struct server_filter_list;
  54 extern char curr_dir[];
  55
  56 char *auth_user;
  57 int read_only = 0;
  58 int module_id = -1;
  59 struct chmod_mode_struct *daemon_chmod_modes;
  60
  61 /* module_dirlen is the length of the module_dir string when in daemon
  62  * mode, not chrooted, and the path is not "/"; otherwise 0. */
  63 char *module_dir = NULL;
  64 unsigned int module_dirlen = 0;
  65
  66 static int rl_nulls = 0;
  67
  68 #ifdef HAVE_SIGACTION
  69 static struct sigaction sigact;
  70 #endif
  71
  72 /**
  73  * Run a client connected to an rsyncd.  The alternative to this
  74  * function for remote-shell connections is do_cmd().
  75  *
  76  * After negotiating which module to use and reading the server's
  77  * motd, this hands over to client_run().  Telling the server the
  78  * module will cause it to chroot/setuid/etc.
  79  *
  80  * Instead of doing a transfer, the client may at this stage instead
  81  * get a listing of remote modules and exit.
  82  *
  83  * @return -1 for error in startup, or the result of client_run().
  84  * Either way, it eventually gets passed to exit_cleanup().
  85  **/
  86 int start_socket_client(char *host, int remote_argc, char *remote_argv[],
  87                         int argc, char *argv[])
  88 {
  89         int fd, ret;
  90         char *p, *user = NULL;
  91
  92         /* This is redundant with code in start_inband_exchange(), but this
  93          * short-circuits a problem in the client before we open a socket,
  94          * and the extra check won't hurt. */
  95         if (**remote_argv == '/') {
  96                 rprintf(FERROR,
  97                         "ERROR: The remote path must start with a module name not a /\n");
  98                 return -1;
  99         }
 100
 101         if ((p = strrchr(host, '@')) != NULL) {
 102                 user = host;
 103                 host = p+1;
 104                 *p = '\0';
 105         }
 106
 107         fd = open_socket_out_wrapped(host, rsync_port, bind_address,
 108                                      default_af_hint);
 109         if (fd == -1)
 110                 exit_cleanup(RERR_SOCKETIO);
 111
 112         set_socket_options(fd, sockopts);
 113
 114         ret = start_inband_exchange(fd, fd, user, remote_argc, remote_argv);
 115
 116         return ret ? ret : client_run(fd, fd, -1, argc, argv);
 117 }
 118
 119 static int exchange_protocols(int f_in, int f_out, char *buf, size_t bufsiz, int am_client)
 120 {
 121         int remote_sub = -1;
 122 #if SUBPROTOCOL_VERSION != 0
 123         int our_sub = protocol_version < PROTOCOL_VERSION ? 0 : SUBPROTOCOL_VERSION;
 124 #else
 125         int our_sub = 0;
 126 #endif
 127         char *motd;
 128
 129         io_printf(f_out, "@RSYNCD: %d.%d\n", protocol_version, our_sub);
 130
 131         if (!am_client) {
 132                 motd = lp_motd_file();
 133                 if (motd && *motd) {
 134                         FILE *f = fopen(motd,"r");
 135                         while (f && !feof(f)) {
 136                                 int len = fread(buf, 1, bufsiz - 1, f);
 137                                 if (len > 0)
 138                                         write_buf(f_out, buf, len);
 139                         }
 140                         if (f)
 141                                 fclose(f);
 142                         write_sbuf(f_out, "\n");
 143                 }
 144         }
 145
 146         /* This strips the \n. */
 147         if (!read_line_old(f_in, buf, bufsiz)) {
 148                 if (am_client)
 149                         rprintf(FERROR, "rsync: did not see server greeting\n");
 150                 return -1;
 151         }
 152
 153         if (sscanf(buf, "@RSYNCD: %d.%d", &remote_protocol, &remote_sub) < 1) {
 154                 if (am_client)
 155                         rprintf(FERROR, "rsync: server sent \"%s\" rather than greeting\n", buf);
 156                 else
 157                         io_printf(f_out, "@ERROR: protocol startup error\n");
 158                 return -1;
 159         }
 160
 161         if (remote_sub < 0) {
 162                 if (remote_protocol == 30) {
 163                         if (am_client)
 164                                 rprintf(FERROR, "rsync: server is speaking an incompatible beta of protocol 30\n");
 165                         else
 166                                 io_printf(f_out, "@ERROR: your client is speaking an incompatible beta of protocol 30\n");
 167                         return -1;
 168                 }
 169                 remote_sub = 0;
 170         }
 171
 172         if (protocol_version > remote_protocol) {
 173                 protocol_version = remote_protocol;
 174                 if (remote_sub)
 175                         protocol_version--;
 176         } else if (protocol_version == remote_protocol) {
 177                 if (remote_sub != our_sub)
 178                         protocol_version--;
 179         }
 180 #if SUBPROTOCOL_VERSION != 0
 181         else if (protocol_version < remote_protocol) {
 182                 if (our_sub)
 183                         protocol_version--;
 184         }
 185 #endif
 186
 187         if (protocol_version >= 30)
 188                 rl_nulls = 1;
 189
 190         return 0;
 191 }
 192
 193 int start_inband_exchange(int f_in, int f_out, const char *user, int argc, char *argv[])
 194 {
 195         int i, modlen;
 196         char line[BIGPATHBUFLEN];
 197         char *sargs[MAX_ARGS];
 198         int sargc = 0;
 199         char *p, *modname;
 200
 201         assert(argc > 0);
 202
 203         if (**argv == '/') {
 204                 rprintf(FERROR,
 205                         "ERROR: The remote path must start with a module name\n");
 206                 return -1;
 207         }
 208
 209         if (!(p = strchr(*argv, '/')))
 210                 modlen = strlen(*argv);
 211         else
 212                 modlen = p - *argv;
 213
 214         if (!(modname = new_array(char, modlen+1+1))) /* room for '/' & '\0' */
 215                 out_of_memory("start_inband_exchange");
 216         strlcpy(modname, *argv, modlen + 1);
 217         modname[modlen] = '/';
 218         modname[modlen+1] = '\0';
 219
 220         if (!user)
 221                 user = getenv("USER");
 222         if (!user)
 223                 user = getenv("LOGNAME");
 224
 225         if (exchange_protocols(f_in, f_out, line, sizeof line, 1) < 0)
 226                 return -1;
 227
 228         /* set daemon_over_rsh to false since we need to build the
 229          * true set of args passed through the rsh/ssh connection;
 230          * this is a no-op for direct-socket-connection mode */
 231         daemon_over_rsh = 0;
 232         server_options(sargs, &sargc);
 233
 234         if (sargc >= MAX_ARGS - 2)
 235                 goto arg_overflow;
 236
 237         sargs[sargc++] = ".";
 238
 239         while (argc > 0) {
 240                 if (sargc >= MAX_ARGS - 1) {
 241                   arg_overflow:
 242                         rprintf(FERROR, "internal: args[] overflowed in do_cmd()\n");
 243                         exit_cleanup(RERR_SYNTAX);
 244                 }
 245                 if (list_only && strncmp(*argv, modname, modlen) == 0
 246                  && argv[0][modlen] == '\0')
 247                         sargs[sargc++] = modname; /* we send "modname/" */
 248                 else
 249                         sargs[sargc++] = *argv;
 250                 argv++;
 251                 argc--;
 252         }
 253
 254         sargs[sargc] = NULL;
 255
 256         if (verbose > 1)
 257                 print_child_argv("sending daemon args:", sargs);
 258
 259         io_printf(f_out, "%.*s\n", modlen, modname);
 260
 261         /* Old servers may just drop the connection here,
 262          rather than sending a proper EXIT command.  Yuck. */
 263         kluge_around_eof = list_only && protocol_version < 25 ? 1 : 0;
 264
 265         while (1) {
 266                 if (!read_line_old(f_in, line, sizeof line)) {
 267                         rprintf(FERROR, "rsync: didn't get server startup line\n");
 268                         return -1;
 269                 }
 270
 271                 if (strncmp(line,"@RSYNCD: AUTHREQD ",18) == 0) {
 272                         auth_client(f_out, user, line+18);
 273                         continue;
 274                 }
 275
 276                 if (strcmp(line,"@RSYNCD: OK") == 0)
 277                         break;
 278
 279                 if (strcmp(line,"@RSYNCD: EXIT") == 0) {
 280                         /* This is sent by recent versions of the
 281                          * server to terminate the listing of modules.
 282                          * We don't want to go on and transfer
 283                          * anything; just exit. */
 284                         exit(0);
 285                 }
 286
 287                 if (strncmp(line, "@ERROR", 6) == 0) {
 288                         rprintf(FERROR, "%s\n", line);
 289                         /* This is always fatal; the server will now
 290                          * close the socket. */
 291                         return -1;
 292                 }
 293
 294                 /* This might be a MOTD line or a module listing, but there is
 295                  * no way to differentiate it.  The manpage mentions this. */
 296                 if (output_motd)
 297                         rprintf(FINFO, "%s\n", line);
 298         }
 299         kluge_around_eof = 0;
 300
 301         if (rl_nulls) {
 302                 for (i = 0; i < sargc; i++) {
 303                         write_sbuf(f_out, sargs[i]);
 304                         write_byte(f_out, 0);
 305                 }
 306                 write_byte(f_out, 0);
 307         } else {
 308                 for (i = 0; i < sargc; i++)
 309                         io_printf(f_out, "%s\n", sargs[i]);
 310                 write_sbuf(f_out, "\n");
 311         }
 312
 313         if (protocol_version < 23) {
 314                 if (protocol_version == 22 || !am_sender)
 315                         io_start_multiplex_in();
 316         }
 317
 318         free(modname);
 319
 320         return 0;
 321 }
 322
 323 static char *finish_pre_exec(pid_t pid, int fd, char *request,
 324                              int argc, char *argv[])
 325 {
 326         int j, status = -1;
 327
 328         if (!request)
 329                 request = "(NONE)";
 330
 331         write_buf(fd, request, strlen(request)+1);
 332         for (j = 0; j < argc; j++)
 333                 write_buf(fd, argv[j], strlen(argv[j])+1);
 334         write_byte(fd, 0);
 335
 336         close(fd);
 337
 338         if (wait_process(pid, &status, 0) < 0
 339          || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 340                 char *e;
 341                 if (asprintf(&e, "pre-xfer exec returned failure (%d)%s%s\n",
 342                              status, status < 0 ? ": " : "",
 343                              status < 0 ? strerror(errno) : "") < 0)
 344                         out_of_memory("finish_pre_exec");
 345                 return e;
 346         }
 347         return NULL;
 348 }
 349
 350 static int read_arg_from_pipe(int fd, char *buf, int limit)
 351 {
 352         char *bp = buf, *eob = buf + limit - 1;
 353
 354         while (1) {
 355             if (read(fd, bp, 1) != 1)
 356                 return -1;
 357             if (*bp == '\0')
 358                 break;
 359             if (bp < eob)
 360                 bp++;
 361         }
 362         *bp = '\0';
 363
 364         return bp - buf;
 365 }
 366
 367 static int rsync_module(int f_in, int f_out, int i, char *addr, char *host)
 368 {
 369         int argc, opt_cnt;
 370         char **argv;
 371         char line[BIGPATHBUFLEN];
 372         uid_t uid = (uid_t)-2;  /* canonically "nobody" */
 373         gid_t gid = (gid_t)-2;
 374         char *p, *err_msg = NULL;
 375         char *name = lp_name(i);
 376         int use_chroot = lp_use_chroot(i);
 377         int ret, pre_exec_fd = -1;
 378         pid_t pre_exec_pid = 0;
 379         char *request = NULL;
 380
 381         if (!allow_access(addr, host, lp_hosts_allow(i), lp_hosts_deny(i))) {
 382                 rprintf(FLOG, "rsync denied on module %s from %s (%s)\n",
 383                         name, host, addr);
 384                 if (!lp_list(i))
 385                         io_printf(f_out, "@ERROR: Unknown module '%s'\n", name);
 386                 else {
 387                         io_printf(f_out,
 388                                   "@ERROR: access denied to %s from %s (%s)\n",
 389                                   name, host, addr);
 390                 }
 391                 return -1;
 392         }
 393
 394         if (am_daemon && am_server) {
 395                 rprintf(FLOG, "rsync allowed access on module %s from %s (%s)\n",
 396                         name, host, addr);
 397         }
 398
 399         if (!claim_connection(lp_lock_file(i), lp_max_connections(i))) {
 400                 if (errno) {
 401                         rsyserr(FLOG, errno, "failed to open lock file %s",
 402                                 lp_lock_file(i));
 403                         io_printf(f_out, "@ERROR: failed to open lock file\n");
 404                 } else {
 405                         rprintf(FLOG, "max connections (%d) reached\n",
 406                                 lp_max_connections(i));
 407                         io_printf(f_out, "@ERROR: max connections (%d) reached -- try again later\n",
 408                                 lp_max_connections(i));
 409                 }
 410                 return -1;
 411         }
 412
 413         auth_user = auth_server(f_in, f_out, i, host, addr, "@RSYNCD: AUTHREQD ");
 414
 415         if (!auth_user) {
 416                 io_printf(f_out, "@ERROR: auth failed on module %s\n", name);
 417                 return -1;
 418         }
 419
 420         module_id = i;
 421
 422         if (lp_read_only(i))
 423                 read_only = 1;
 424
 425         if (lp_transfer_logging(i) && !logfile_format)
 426                 logfile_format = lp_log_format(i);
 427         if (log_format_has(logfile_format, 'i'))
 428                 logfile_format_has_i = 1;
 429         if (logfile_format_has_i || log_format_has(logfile_format, 'o'))
 430                 logfile_format_has_o_or_i = 1;
 431
 432         am_root = (MY_UID() == 0);
 433
 434         if (am_root) {
 435                 p = lp_uid(i);
 436                 if (!name_to_uid(p, &uid)) {
 437                         if (!isDigit(p)) {
 438                                 rprintf(FLOG, "Invalid uid %s\n", p);
 439                                 io_printf(f_out, "@ERROR: invalid uid %s\n", p);
 440                                 return -1;
 441                         }
 442                         uid = atoi(p);
 443                 }
 444
 445                 p = lp_gid(i);
 446                 if (!name_to_gid(p, &gid)) {
 447                         if (!isDigit(p)) {
 448                                 rprintf(FLOG, "Invalid gid %s\n", p);
 449                                 io_printf(f_out, "@ERROR: invalid gid %s\n", p);
 450                                 return -1;
 451                         }
 452                         gid = atoi(p);
 453                 }
 454         }
 455
 456         /* TODO: If we're not root, but the configuration requests
 457          * that we change to some uid other than the current one, then
 458          * log a warning. */
 459
 460         /* TODO: Perhaps take a list of gids, and make them into the
 461          * supplementary groups. */
 462
 463         /* We do a push_dir() without actually calling chdir() in order
 464          * to make sure that the module's path is absolute.  After this
 465          * check, module_dir will be set to an absolute path. */
 466         module_dir = lp_path(i);
 467         strlcpy(line, curr_dir, sizeof line);
 468         if (!push_dir(module_dir, 1))
 469                 goto chdir_failed;
 470         if (strcmp(curr_dir, module_dir) != 0)
 471                 module_dir = strdup(curr_dir);
 472         push_dir(line, 1); /* Restore curr_dir. */
 473
 474         if (use_chroot || (module_dirlen = strlen(module_dir)) == 1) {
 475                 module_dirlen = 0;
 476                 set_filter_dir("/", 1);
 477         } else
 478                 set_filter_dir(module_dir, module_dirlen);
 479
 480         p = lp_filter(i);
 481         parse_rule(&server_filter_list, p, MATCHFLG_WORD_SPLIT,
 482                    XFLG_ABS_IF_SLASH);
 483
 484         p = lp_include_from(i);
 485         parse_filter_file(&server_filter_list, p, MATCHFLG_INCLUDE,
 486             XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES | XFLG_FATAL_ERRORS);
 487
 488         p = lp_include(i);
 489         parse_rule(&server_filter_list, p,
 490                    MATCHFLG_INCLUDE | MATCHFLG_WORD_SPLIT,
 491                    XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES);
 492
 493         p = lp_exclude_from(i);
 494         parse_filter_file(&server_filter_list, p, 0,
 495             XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES | XFLG_FATAL_ERRORS);
 496
 497         p = lp_exclude(i);
 498         parse_rule(&server_filter_list, p, MATCHFLG_WORD_SPLIT,
 499                    XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES);
 500
 501         log_init(1);
 502
 503 #ifdef HAVE_PUTENV
 504         if (*lp_prexfer_exec(i) || *lp_postxfer_exec(i)) {
 505                 char *modname, *modpath, *hostaddr, *hostname, *username;
 506                 int status;
 507                 if (asprintf(&modname, "RSYNC_MODULE_NAME=%s", name) < 0
 508                  || asprintf(&modpath, "RSYNC_MODULE_PATH=%s", module_dir) < 0
 509                  || asprintf(&hostaddr, "RSYNC_HOST_ADDR=%s", addr) < 0
 510                  || asprintf(&hostname, "RSYNC_HOST_NAME=%s", host) < 0
 511                  || asprintf(&username, "RSYNC_USER_NAME=%s", auth_user) < 0)
 512                         out_of_memory("rsync_module");
 513                 putenv(modname);
 514                 putenv(modpath);
 515                 putenv(hostaddr);
 516                 putenv(hostname);
 517                 putenv(username);
 518                 umask(orig_umask);
 519                 /* For post-xfer exec, fork a new process to run the rsync
 520                  * daemon while this process waits for the exit status and
 521                  * runs the indicated command at that point. */
 522                 if (*lp_postxfer_exec(i)) {
 523                         pid_t pid = fork();
 524                         if (pid < 0) {
 525                                 rsyserr(FLOG, errno, "fork failed");
 526                                 io_printf(f_out, "@ERROR: fork failed\n");
 527                                 return -1;
 528                         }
 529                         if (pid) {
 530                                 if (asprintf(&p, "RSYNC_PID=%ld", (long)pid) > 0)
 531                                         putenv(p);
 532                                 if (wait_process(pid, &status, 0) < 0)
 533                                         status = -1;
 534                                 if (asprintf(&p, "RSYNC_RAW_STATUS=%d", status) > 0)
 535                                         putenv(p);
 536                                 if (WIFEXITED(status))
 537                                         status = WEXITSTATUS(status);
 538                                 else
 539                                         status = -1;
 540                                 if (asprintf(&p, "RSYNC_EXIT_STATUS=%d", status) > 0)
 541                                         putenv(p);
 542                                 system(lp_postxfer_exec(i));
 543                                 _exit(status);
 544                         }
 545                 }
 546                 /* For pre-xfer exec, fork a child process to run the indicated
 547                  * command, though it first waits for the parent process to
 548                  * send us the user's request via a pipe. */
 549                 if (*lp_prexfer_exec(i)) {
 550                         int fds[2];
 551                         if (asprintf(&p, "RSYNC_PID=%ld", (long)getpid()) > 0)
 552                                 putenv(p);
 553                         if (pipe(fds) < 0 || (pre_exec_pid = fork()) < 0) {
 554                                 rsyserr(FLOG, errno, "pre-xfer exec preparation failed");
 555                                 io_printf(f_out, "@ERROR: pre-xfer exec preparation failed\n");
 556                                 return -1;
 557                         }
 558                         if (pre_exec_pid == 0) {
 559                                 char buf[BIGPATHBUFLEN];
 560                                 int j, len;
 561                                 close(fds[1]);
 562                                 set_blocking(fds[0]);
 563                                 len = read_arg_from_pipe(fds[0], buf, BIGPATHBUFLEN);
 564                                 if (len <= 0)
 565                                         _exit(1);
 566                                 if (asprintf(&p, "RSYNC_REQUEST=%s", buf) > 0)
 567                                         putenv(p);
 568                                 for (j = 0; ; j++) {
 569                                         len = read_arg_from_pipe(fds[0], buf,
 570                                                                  BIGPATHBUFLEN);
 571                                         if (len <= 0) {
 572                                                 if (!len)
 573                                                         break;
 574                                                 _exit(1);
 575                                         }
 576                                         if (asprintf(&p, "RSYNC_ARG%d=%s", j, buf) > 0)
 577                                                 putenv(p);
 578                                 }
 579                                 close(fds[0]);
 580                                 close(STDIN_FILENO);
 581                                 close(STDOUT_FILENO);
 582                                 status = system(lp_prexfer_exec(i));
 583                                 if (!WIFEXITED(status))
 584                                         _exit(1);
 585                                 _exit(WEXITSTATUS(status));
 586                         }
 587                         close(fds[0]);
 588                         set_blocking(fds[1]);
 589                         pre_exec_fd = fds[1];
 590                 }
 591                 umask(0);
 592         }
 593 #endif
 594
 595         if (use_chroot) {
 596                 /*
 597                  * XXX: The 'use chroot' flag is a fairly reliable
 598                  * source of confusion, because it fails under two
 599                  * important circumstances: running as non-root,
 600                  * running on Win32 (or possibly others).  On the
 601                  * other hand, if you are running as root, then it
 602                  * might be better to always use chroot.
 603                  *
 604                  * So, perhaps if we can't chroot we should just issue
 605                  * a warning, unless a "require chroot" flag is set,
 606                  * in which case we fail.
 607                  */
 608                 if (chroot(module_dir)) {
 609                         rsyserr(FLOG, errno, "chroot %s failed", module_dir);
 610                         io_printf(f_out, "@ERROR: chroot failed\n");
 611                         return -1;
 612                 }
 613                 if (!push_dir("/", 0))
 614                         goto chdir_failed;
 615         } else {
 616                 if (!push_dir(module_dir, 0)) {
 617                   chdir_failed:
 618                         rsyserr(FLOG, errno, "chdir %s failed\n", module_dir);
 619                         io_printf(f_out, "@ERROR: chdir failed\n");
 620                         return -1;
 621                 }
 622                 sanitize_paths = 1;
 623         }
 624
 625         if (am_root) {
 626                 /* XXXX: You could argue that if the daemon is started
 627                  * by a non-root user and they explicitly specify a
 628                  * gid, then we should try to change to that gid --
 629                  * this could be possible if it's already in their
 630                  * supplementary groups. */
 631
 632                 /* TODO: Perhaps we need to document that if rsyncd is
 633                  * started by somebody other than root it will inherit
 634                  * all their supplementary groups. */
 635
 636                 if (setgid(gid)) {
 637                         rsyserr(FLOG, errno, "setgid %d failed", (int)gid);
 638                         io_printf(f_out, "@ERROR: setgid failed\n");
 639                         return -1;
 640                 }
 641 #ifdef HAVE_SETGROUPS
 642                 /* Get rid of any supplementary groups this process
 643                  * might have inheristed. */
 644                 if (setgroups(1, &gid)) {
 645                         rsyserr(FLOG, errno, "setgroups failed");
 646                         io_printf(f_out, "@ERROR: setgroups failed\n");
 647                         return -1;
 648                 }
 649 #endif
 650
 651                 if (setuid(uid)) {
 652                         rsyserr(FLOG, errno, "setuid %d failed", (int)uid);
 653                         io_printf(f_out, "@ERROR: setuid failed\n");
 654                         return -1;
 655                 }
 656
 657                 am_root = (MY_UID() == 0);
 658         }
 659
 660         if (lp_temp_dir(i) && *lp_temp_dir(i)) {
 661                 tmpdir = lp_temp_dir(i);
 662                 if (strlen(tmpdir) >= MAXPATHLEN - 10) {
 663                         rprintf(FLOG,
 664                                 "the 'temp dir' value for %s is WAY too long -- ignoring.\n",
 665                                 name);
 666                         tmpdir = NULL;
 667                 }
 668         }
 669
 670         io_printf(f_out, "@RSYNCD: OK\n");
 671
 672         opt_cnt = read_args(f_in, name, line, sizeof line, rl_nulls, &argv, &argc, &request);
 673
 674         if (pre_exec_pid) {
 675                 err_msg = finish_pre_exec(pre_exec_pid, pre_exec_fd, request,
 676                                           opt_cnt, argv);
 677         }
 678
 679         verbose = 0; /* future verbosity is controlled by client options */
 680         ret = parse_arguments(&argc, (const char ***) &argv, 0);
 681         am_server = 1; /* Don't let someone try to be tricky. */
 682         if (lp_ignore_errors(module_id))
 683                 ignore_errors = 1;
 684
 685         if (lp_fake_super(i))
 686                 am_root = -1;
 687         else if (am_root < 0) /* Treat --fake-super from client as --super. */
 688                 am_root = 2;
 689
 690         if (filesfrom_fd == 0)
 691                 filesfrom_fd = f_in;
 692
 693         if (request) {
 694                 if (*auth_user) {
 695                         rprintf(FLOG, "rsync %s %s from %s@%s (%s)\n",
 696                                 am_sender ? "on" : "to",
 697                                 request, auth_user, host, addr);
 698                 } else {
 699                         rprintf(FLOG, "rsync %s %s from %s (%s)\n",
 700                                 am_sender ? "on" : "to",
 701                                 request, host, addr);
 702                 }
 703                 free(request);
 704         }
 705
 706 #ifndef DEBUG
 707         /* don't allow the logs to be flooded too fast */
 708         if (verbose > lp_max_verbosity(i))
 709                 verbose = lp_max_verbosity(i);
 710 #endif
 711
 712         if (protocol_version < 23
 713             && (protocol_version == 22 || am_sender))
 714                 io_start_multiplex_out();
 715         else if (!ret || err_msg) {
 716                 /* We have to get I/O multiplexing started so that we can
 717                  * get the error back to the client.  This means getting
 718                  * the protocol setup finished first in later versions. */
 719                 setup_protocol(f_out, f_in);
 720                 if (!am_sender) {
 721                         /* Since we failed in our option parsing, we may not
 722                          * have finished parsing that the client sent us a
 723                          * --files-from option, so look for it manually.
 724                          * Without this, the socket would be in the wrong
 725                          * state for the upcoming error message. */
 726                         if (!files_from) {
 727                                 int i;
 728                                 for (i = 0; i < argc; i++) {
 729                                         if (strncmp(argv[i], "--files-from", 12) == 0) {
 730                                                 files_from = "";
 731                                                 break;
 732                                         }
 733                                 }
 734                         }
 735                         if (files_from)
 736                                 write_byte(f_out, 0);
 737                 }
 738                 io_start_multiplex_out();
 739         }
 740
 741         if (!ret || err_msg) {
 742                 if (err_msg)
 743                         rwrite(FERROR, err_msg, strlen(err_msg), 0);
 744                 else
 745                         option_error();
 746                 msleep(400);
 747                 exit_cleanup(RERR_UNSUPPORTED);
 748         }
 749
 750         if (lp_timeout(i) && lp_timeout(i) > io_timeout)
 751                 set_io_timeout(lp_timeout(i));
 752
 753         /* If we have some incoming/outgoing chmod changes, append them to
 754          * any user-specified changes (making our changes have priority).
 755          * We also get a pointer to just our changes so that a receiver
 756          * process can use them separately if --perms wasn't specified. */
 757         if (am_sender)
 758                 p = lp_outgoing_chmod(i);
 759         else
 760                 p = lp_incoming_chmod(i);
 761         if (*p && !(daemon_chmod_modes = parse_chmod(p, &chmod_modes))) {
 762                 rprintf(FLOG, "Invalid \"%sing chmod\" directive: %s\n",
 763                         am_sender ? "outgo" : "incom", p);
 764         }
 765
 766         start_server(f_in, f_out, argc, argv);
 767
 768         return 0;
 769 }
 770
 771 /* send a list of available modules to the client. Don't list those
 772    with "list = False". */
 773 static void send_listing(int fd)
 774 {
 775         int n = lp_numservices();
 776         int i;
 777
 778         for (i = 0; i < n; i++) {
 779                 if (lp_list(i))
 780                         io_printf(fd, "%-15s\t%s\n", lp_name(i), lp_comment(i));
 781         }
 782
 783         if (protocol_version >= 25)
 784                 io_printf(fd,"@RSYNCD: EXIT\n");
 785 }
 786
 787 /* this is called when a connection is established to a client
 788    and we want to start talking. The setup of the system is done from
 789    here */
 790 int start_daemon(int f_in, int f_out)
 791 {
 792         char line[1024];
 793         char *addr, *host;
 794         int i;
 795
 796         io_set_sock_fds(f_in, f_out);
 797
 798         /* We must load the config file before calling any function that
 799          * might cause log-file output to occur.  This ensures that the
 800          * "log file" param gets honored for the 2 non-forked use-cases
 801          * (when rsync is run by init and run by a remote shell). */
 802         if (!lp_load(config_file, 0))
 803                 exit_cleanup(RERR_SYNTAX);
 804
 805         addr = client_addr(f_in);
 806         host = client_name(f_in);
 807         rprintf(FLOG, "connect from %s (%s)\n", host, addr);
 808
 809         if (!am_server) {
 810                 set_socket_options(f_in, "SO_KEEPALIVE");
 811                 if (sockopts)
 812                         set_socket_options(f_in, sockopts);
 813                 else
 814                         set_socket_options(f_in, lp_socket_options());
 815                 set_nonblocking(f_in);
 816         }
 817
 818         if (exchange_protocols(f_in, f_out, line, sizeof line, 0) < 0)
 819                 return -1;
 820
 821         line[0] = 0;
 822         if (!read_line_old(f_in, line, sizeof line))
 823                 return -1;
 824
 825         if (!*line || strcmp(line, "#list") == 0) {
 826                 rprintf(FLOG, "module-list request from %s (%s)\n",
 827                         host, addr);
 828                 send_listing(f_out);
 829                 return -1;
 830         }
 831
 832         if (*line == '#') {
 833                 /* it's some sort of command that I don't understand */
 834                 io_printf(f_out, "@ERROR: Unknown command '%s'\n", line);
 835                 return -1;
 836         }
 837
 838         if ((i = lp_number(line)) < 0) {
 839                 rprintf(FLOG, "unknown module '%s' tried from %s (%s)\n",
 840                         line, host, addr);
 841                 io_printf(f_out, "@ERROR: Unknown module '%s'\n", line);
 842                 return -1;
 843         }
 844
 845 #ifdef HAVE_SIGACTION
 846         sigact.sa_flags = SA_NOCLDSTOP;
 847 #endif
 848         SIGACTION(SIGCHLD, remember_children);
 849
 850         return rsync_module(f_in, f_out, i, addr, host);
 851 }
 852
 853 static void create_pid_file(void)
 854 {
 855         char *pid_file = lp_pid_file();
 856         char pidbuf[16];
 857         pid_t pid = getpid();
 858         int fd;
 859
 860         if (!pid_file || !*pid_file)
 861                 return;
 862
 863         cleanup_set_pid(pid);
 864         if ((fd = do_open(pid_file, O_WRONLY|O_CREAT|O_EXCL, 0666 & ~orig_umask)) == -1) {
 865                 cleanup_set_pid(0);
 866                 fprintf(stderr, "failed to create pid file %s: %s\n", pid_file, strerror(errno));
 867                 rsyserr(FLOG, errno, "failed to create pid file %s", pid_file);
 868                 exit_cleanup(RERR_FILEIO);
 869         }
 870         snprintf(pidbuf, sizeof pidbuf, "%ld\n", (long)pid);
 871         write(fd, pidbuf, strlen(pidbuf));
 872         close(fd);
 873 }
 874
 875 /* Become a daemon, discarding the controlling terminal. */
 876 static void become_daemon(void)
 877 {
 878         int i;
 879         pid_t pid = fork();
 880
 881         if (pid) {
 882                 if (pid < 0) {
 883                         fprintf(stderr, "failed to fork: %s\n", strerror(errno));
 884                         exit_cleanup(RERR_FILEIO);
 885                 }
 886                 _exit(0);
 887         }
 888
 889         create_pid_file();
 890
 891         /* detach from the terminal */
 892 #ifdef HAVE_SETSID
 893         setsid();
 894 #elif defined TIOCNOTTY
 895         i = open("/dev/tty", O_RDWR);
 896         if (i >= 0) {
 897                 ioctl(i, (int)TIOCNOTTY, (char *)0);
 898                 close(i);
 899         }
 900 #endif
 901         /* make sure that stdin, stdout an stderr don't stuff things
 902          * up (library functions, for example) */
 903         for (i = 0; i < 3; i++) {
 904                 close(i);
 905                 open("/dev/null", O_RDWR);
 906         }
 907 }
 908
 909 int daemon_main(void)
 910 {
 911         if (!config_file) {
 912                 if (am_server && am_root <= 0)
 913                         config_file = RSYNCD_USERCONF;
 914                 else
 915                         config_file = RSYNCD_SYSCONF;
 916         }
 917
 918         if (is_a_socket(STDIN_FILENO)) {
 919                 int i;
 920
 921                 /* we are running via inetd - close off stdout and
 922                  * stderr so that library functions (and getopt) don't
 923                  * try to use them. Redirect them to /dev/null */
 924                 for (i = 1; i < 3; i++) {
 925                         close(i);
 926                         open("/dev/null", O_RDWR);
 927                 }
 928
 929                 return start_daemon(STDIN_FILENO, STDIN_FILENO);
 930         }
 931
 932         if (!lp_load(config_file, 1)) {
 933                 fprintf(stderr, "Failed to parse config file: %s\n", config_file);
 934                 exit_cleanup(RERR_SYNTAX);
 935         }
 936
 937         if (no_detach)
 938                 create_pid_file();
 939         else
 940                 become_daemon();
 941
 942         if (rsync_port == 0 && (rsync_port = lp_rsync_port()) == 0)
 943                 rsync_port = RSYNC_PORT;
 944         if (bind_address == NULL && *lp_bind_address())
 945                 bind_address = lp_bind_address();
 946
 947         log_init(0);
 948
 949         rprintf(FLOG, "rsyncd version %s starting, listening on port %d\n",
 950                 RSYNC_VERSION, rsync_port);
 951         /* TODO: If listening on a particular address, then show that
 952          * address too.  In fact, why not just do inet_ntop on the
 953          * local address??? */
 954
 955         start_accept_loop(rsync_port, start_daemon);
 956         return -1;
 957 }