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