2 * The socket based protocol for setting up a connection with rsyncd.
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
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.
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.
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.
27 extern int output_motd;
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;
43 extern int default_af_hint;
44 extern int logfile_format_has_i;
45 extern int logfile_format_has_o_or_i;
46 extern mode_t orig_umask;
47 extern char *bind_address;
48 extern char *sockopts;
49 extern char *config_file;
50 extern char *logfile_format;
51 extern char *files_from;
53 extern struct chmod_mode_struct *chmod_modes;
54 extern struct filter_list_struct server_filter_list;
55 extern char curr_dir[];
60 struct chmod_mode_struct *daemon_chmod_modes;
62 /* module_dirlen is the length of the module_dir string when in daemon
63 * mode, not chrooted, and the path is not "/"; otherwise 0. */
64 char *module_dir = NULL;
65 unsigned int module_dirlen = 0;
67 static int rl_nulls = 0;
70 static struct sigaction sigact;
74 * Run a client connected to an rsyncd. The alternative to this
75 * function for remote-shell connections is do_cmd().
77 * After negotiating which module to use and reading the server's
78 * motd, this hands over to client_run(). Telling the server the
79 * module will cause it to chroot/setuid/etc.
81 * Instead of doing a transfer, the client may at this stage instead
82 * get a listing of remote modules and exit.
84 * @return -1 for error in startup, or the result of client_run().
85 * Either way, it eventually gets passed to exit_cleanup().
87 int start_socket_client(char *host, int remote_argc, char *remote_argv[],
88 int argc, char *argv[])
91 char *p, *user = NULL;
93 /* This is redundant with code in start_inband_exchange(), but this
94 * short-circuits a problem in the client before we open a socket,
95 * and the extra check won't hurt. */
96 if (**remote_argv == '/') {
98 "ERROR: The remote path must start with a module name not a /\n");
102 if ((p = strrchr(host, '@')) != NULL) {
108 fd = open_socket_out_wrapped(host, rsync_port, bind_address,
111 exit_cleanup(RERR_SOCKETIO);
113 set_socket_options(fd, sockopts);
115 ret = start_inband_exchange(fd, fd, user, remote_argc, remote_argv);
117 return ret ? ret : client_run(fd, fd, -1, argc, argv);
120 static int exchange_protocols(int f_in, int f_out, char *buf, size_t bufsiz, int am_client)
123 #if SUBPROTOCOL_VERSION != 0
124 int our_sub = protocol_version < PROTOCOL_VERSION ? 0 : SUBPROTOCOL_VERSION;
130 io_printf(f_out, "@RSYNCD: %d.%d\n", protocol_version, our_sub);
133 motd = lp_motd_file();
135 FILE *f = fopen(motd,"r");
136 while (f && !feof(f)) {
137 int len = fread(buf, 1, bufsiz - 1, f);
139 write_buf(f_out, buf, len);
143 write_sbuf(f_out, "\n");
147 /* This strips the \n. */
148 if (!read_line_old(f_in, buf, bufsiz)) {
150 rprintf(FERROR, "rsync: did not see server greeting\n");
154 if (sscanf(buf, "@RSYNCD: %d.%d", &remote_protocol, &remote_sub) < 1) {
156 rprintf(FERROR, "rsync: server sent \"%s\" rather than greeting\n", buf);
158 io_printf(f_out, "@ERROR: protocol startup error\n");
162 if (remote_sub < 0) {
163 if (remote_protocol == 30) {
165 rprintf(FERROR, "rsync: server is speaking an incompatible beta of protocol 30\n");
167 io_printf(f_out, "@ERROR: your client is speaking an incompatible beta of protocol 30\n");
173 if (protocol_version > remote_protocol) {
174 protocol_version = remote_protocol;
177 } else if (protocol_version == remote_protocol) {
178 if (remote_sub != our_sub)
181 #if SUBPROTOCOL_VERSION != 0
182 else if (protocol_version < remote_protocol) {
188 if (protocol_version >= 30)
194 int start_inband_exchange(int f_in, int f_out, const char *user, int argc, char *argv[])
197 char line[BIGPATHBUFLEN];
198 char *sargs[MAX_ARGS];
200 char *p, *path = *argv;
202 if (argc == 0 && !am_sender)
207 "ERROR: The remote path must start with a module name\n");
212 user = getenv("USER");
214 user = getenv("LOGNAME");
216 if (exchange_protocols(f_in, f_out, line, sizeof line, 1) < 0)
219 if (list_only && protocol_version >= 29)
222 /* set daemon_over_rsh to false since we need to build the
223 * true set of args passed through the rsh/ssh connection;
224 * this is a no-op for direct-socket-connection mode */
226 server_options(sargs, &sargc);
228 if (sargc >= MAX_ARGS - 2)
231 sargs[sargc++] = ".";
234 if (sargc >= MAX_ARGS - 1) {
236 rprintf(FERROR, "internal: args[] overflowed in do_cmd()\n");
237 exit_cleanup(RERR_SYNTAX);
239 sargs[sargc++] = *argv++;
246 print_child_argv("sending daemon args:", sargs);
248 p = strchr(path, '/');
250 io_printf(f_out, "%s\n", path);
253 /* Old servers may just drop the connection here,
254 rather than sending a proper EXIT command. Yuck. */
255 kluge_around_eof = list_only && protocol_version < 25 ? 1 : 0;
258 if (!read_line_old(f_in, line, sizeof line)) {
259 rprintf(FERROR, "rsync: didn't get server startup line\n");
263 if (strncmp(line,"@RSYNCD: AUTHREQD ",18) == 0) {
264 auth_client(f_out, user, line+18);
268 if (strcmp(line,"@RSYNCD: OK") == 0)
271 if (strcmp(line,"@RSYNCD: EXIT") == 0) {
272 /* This is sent by recent versions of the
273 * server to terminate the listing of modules.
274 * We don't want to go on and transfer
275 * anything; just exit. */
279 if (strncmp(line, "@ERROR", 6) == 0) {
280 rprintf(FERROR, "%s\n", line);
281 /* This is always fatal; the server will now
282 * close the socket. */
286 /* This might be a MOTD line or a module listing, but there is
287 * no way to differentiate it. The manpage mentions this. */
289 rprintf(FINFO, "%s\n", line);
291 kluge_around_eof = 0;
294 for (i = 0; i < sargc; i++) {
295 write_sbuf(f_out, sargs[i]);
296 write_byte(f_out, 0);
298 write_byte(f_out, 0);
300 for (i = 0; i < sargc; i++)
301 io_printf(f_out, "%s\n", sargs[i]);
302 write_sbuf(f_out, "\n");
305 if (protocol_version < 23) {
306 if (protocol_version == 22 || !am_sender)
307 io_start_multiplex_in();
313 static char *finish_pre_exec(pid_t pid, int fd, char *request,
314 int argc, char *argv[])
321 write_buf(fd, request, strlen(request)+1);
322 for (j = 0; j < argc; j++)
323 write_buf(fd, argv[j], strlen(argv[j])+1);
328 if (wait_process(pid, &status, 0) < 0
329 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
331 if (asprintf(&e, "pre-xfer exec returned failure (%d)%s%s\n",
332 status, status < 0 ? ": " : "",
333 status < 0 ? strerror(errno) : "") < 0)
334 out_of_memory("finish_pre_exec");
340 static int read_arg_from_pipe(int fd, char *buf, int limit)
342 char *bp = buf, *eob = buf + limit - 1;
345 if (read(fd, bp, 1) != 1)
357 static int rsync_module(int f_in, int f_out, int i, char *addr, char *host)
361 char line[BIGPATHBUFLEN];
362 uid_t uid = (uid_t)-2; /* canonically "nobody" */
363 gid_t gid = (gid_t)-2;
364 char *p, *err_msg = NULL;
365 char *name = lp_name(i);
366 int use_chroot = lp_use_chroot(i);
367 int ret, pre_exec_fd = -1;
368 pid_t pre_exec_pid = 0;
369 char *request = NULL;
371 if (!allow_access(addr, host, lp_hosts_allow(i), lp_hosts_deny(i))) {
372 rprintf(FLOG, "rsync denied on module %s from %s (%s)\n",
375 io_printf(f_out, "@ERROR: Unknown module '%s'\n", name);
378 "@ERROR: access denied to %s from %s (%s)\n",
384 if (am_daemon && am_server) {
385 rprintf(FLOG, "rsync allowed access on module %s from %s (%s)\n",
389 if (!claim_connection(lp_lock_file(i), lp_max_connections(i))) {
391 rsyserr(FLOG, errno, "failed to open lock file %s",
393 io_printf(f_out, "@ERROR: failed to open lock file\n");
395 rprintf(FLOG, "max connections (%d) reached\n",
396 lp_max_connections(i));
397 io_printf(f_out, "@ERROR: max connections (%d) reached -- try again later\n",
398 lp_max_connections(i));
403 auth_user = auth_server(f_in, f_out, i, host, addr, "@RSYNCD: AUTHREQD ");
406 io_printf(f_out, "@ERROR: auth failed on module %s\n", name);
415 if (lp_transfer_logging(i) && !logfile_format)
416 logfile_format = lp_log_format(i);
417 if (log_format_has(logfile_format, 'i'))
418 logfile_format_has_i = 1;
419 if (logfile_format_has_i || log_format_has(logfile_format, 'o'))
420 logfile_format_has_o_or_i = 1;
422 am_root = (MY_UID() == 0);
426 if (!name_to_uid(p, &uid)) {
428 rprintf(FLOG, "Invalid uid %s\n", p);
429 io_printf(f_out, "@ERROR: invalid uid %s\n", p);
436 if (!name_to_gid(p, &gid)) {
438 rprintf(FLOG, "Invalid gid %s\n", p);
439 io_printf(f_out, "@ERROR: invalid gid %s\n", p);
446 /* TODO: If we're not root, but the configuration requests
447 * that we change to some uid other than the current one, then
450 /* TODO: Perhaps take a list of gids, and make them into the
451 * supplementary groups. */
453 /* We do a push_dir() without actually calling chdir() in order
454 * to make sure that the module's path is absolute. After this
455 * check, module_dir will be set to an absolute path. */
456 module_dir = lp_path(i);
457 strlcpy(line, curr_dir, sizeof line);
458 if (!push_dir(module_dir, 1))
460 if (strcmp(curr_dir, module_dir) != 0)
461 module_dir = strdup(curr_dir);
462 push_dir(line, 1); /* Restore curr_dir. */
464 if (use_chroot || (module_dirlen = strlen(module_dir)) == 1) {
466 set_filter_dir("/", 1);
468 set_filter_dir(module_dir, module_dirlen);
471 parse_rule(&server_filter_list, p, MATCHFLG_WORD_SPLIT,
474 p = lp_include_from(i);
475 parse_filter_file(&server_filter_list, p, MATCHFLG_INCLUDE,
476 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES | XFLG_FATAL_ERRORS);
479 parse_rule(&server_filter_list, p,
480 MATCHFLG_INCLUDE | MATCHFLG_WORD_SPLIT,
481 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES);
483 p = lp_exclude_from(i);
484 parse_filter_file(&server_filter_list, p, 0,
485 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES | XFLG_FATAL_ERRORS);
488 parse_rule(&server_filter_list, p, MATCHFLG_WORD_SPLIT,
489 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES);
494 if (*lp_prexfer_exec(i) || *lp_postxfer_exec(i)) {
495 char *modname, *modpath, *hostaddr, *hostname, *username;
497 if (asprintf(&modname, "RSYNC_MODULE_NAME=%s", name) < 0
498 || asprintf(&modpath, "RSYNC_MODULE_PATH=%s", module_dir) < 0
499 || asprintf(&hostaddr, "RSYNC_HOST_ADDR=%s", addr) < 0
500 || asprintf(&hostname, "RSYNC_HOST_NAME=%s", host) < 0
501 || asprintf(&username, "RSYNC_USER_NAME=%s", auth_user) < 0)
502 out_of_memory("rsync_module");
509 /* For post-xfer exec, fork a new process to run the rsync
510 * daemon while this process waits for the exit status and
511 * runs the indicated command at that point. */
512 if (*lp_postxfer_exec(i)) {
515 rsyserr(FLOG, errno, "fork failed");
516 io_printf(f_out, "@ERROR: fork failed\n");
520 if (asprintf(&p, "RSYNC_PID=%ld", (long)pid) > 0)
522 if (wait_process(pid, &status, 0) < 0)
524 if (asprintf(&p, "RSYNC_RAW_STATUS=%d", status) > 0)
526 if (WIFEXITED(status))
527 status = WEXITSTATUS(status);
530 if (asprintf(&p, "RSYNC_EXIT_STATUS=%d", status) > 0)
532 system(lp_postxfer_exec(i));
536 /* For pre-xfer exec, fork a child process to run the indicated
537 * command, though it first waits for the parent process to
538 * send us the user's request via a pipe. */
539 if (*lp_prexfer_exec(i)) {
541 if (asprintf(&p, "RSYNC_PID=%ld", (long)getpid()) > 0)
543 if (pipe(fds) < 0 || (pre_exec_pid = fork()) < 0) {
544 rsyserr(FLOG, errno, "pre-xfer exec preparation failed");
545 io_printf(f_out, "@ERROR: pre-xfer exec preparation failed\n");
548 if (pre_exec_pid == 0) {
549 char buf[BIGPATHBUFLEN];
552 set_blocking(fds[0]);
553 len = read_arg_from_pipe(fds[0], buf, BIGPATHBUFLEN);
556 if (asprintf(&p, "RSYNC_REQUEST=%s", buf) > 0)
559 len = read_arg_from_pipe(fds[0], buf,
566 if (asprintf(&p, "RSYNC_ARG%d=%s", j, buf) > 0)
571 close(STDOUT_FILENO);
572 status = system(lp_prexfer_exec(i));
573 if (!WIFEXITED(status))
575 _exit(WEXITSTATUS(status));
578 set_blocking(fds[1]);
579 pre_exec_fd = fds[1];
587 * XXX: The 'use chroot' flag is a fairly reliable
588 * source of confusion, because it fails under two
589 * important circumstances: running as non-root,
590 * running on Win32 (or possibly others). On the
591 * other hand, if you are running as root, then it
592 * might be better to always use chroot.
594 * So, perhaps if we can't chroot we should just issue
595 * a warning, unless a "require chroot" flag is set,
596 * in which case we fail.
598 if (chroot(module_dir)) {
599 rsyserr(FLOG, errno, "chroot %s failed", module_dir);
600 io_printf(f_out, "@ERROR: chroot failed\n");
603 if (!push_dir("/", 0))
606 if (!push_dir(module_dir, 0)) {
608 rsyserr(FLOG, errno, "chdir %s failed\n", module_dir);
609 io_printf(f_out, "@ERROR: chdir failed\n");
616 /* XXXX: You could argue that if the daemon is started
617 * by a non-root user and they explicitly specify a
618 * gid, then we should try to change to that gid --
619 * this could be possible if it's already in their
620 * supplementary groups. */
622 /* TODO: Perhaps we need to document that if rsyncd is
623 * started by somebody other than root it will inherit
624 * all their supplementary groups. */
627 rsyserr(FLOG, errno, "setgid %d failed", (int)gid);
628 io_printf(f_out, "@ERROR: setgid failed\n");
631 #ifdef HAVE_SETGROUPS
632 /* Get rid of any supplementary groups this process
633 * might have inheristed. */
634 if (setgroups(1, &gid)) {
635 rsyserr(FLOG, errno, "setgroups failed");
636 io_printf(f_out, "@ERROR: setgroups failed\n");
642 rsyserr(FLOG, errno, "setuid %d failed", (int)uid);
643 io_printf(f_out, "@ERROR: setuid failed\n");
647 am_root = (MY_UID() == 0);
650 if (lp_temp_dir(i) && *lp_temp_dir(i)) {
651 tmpdir = lp_temp_dir(i);
652 if (strlen(tmpdir) >= MAXPATHLEN - 10) {
654 "the 'temp dir' value for %s is WAY too long -- ignoring.\n",
660 io_printf(f_out, "@RSYNCD: OK\n");
662 opt_cnt = read_args(f_in, name, line, sizeof line, rl_nulls, &argv, &argc, &request);
665 err_msg = finish_pre_exec(pre_exec_pid, pre_exec_fd, request,
669 verbose = 0; /* future verbosity is controlled by client options */
670 ret = parse_arguments(&argc, (const char ***) &argv, 0);
671 am_server = 1; /* Don't let someone try to be tricky. */
672 if (lp_ignore_errors(module_id))
675 if (lp_fake_super(i))
677 else if (am_root < 0) /* Treat --fake-super from client as --super. */
680 if (filesfrom_fd == 0)
685 rprintf(FLOG, "rsync %s %s from %s@%s (%s)\n",
686 am_sender ? "on" : "to",
687 request, auth_user, host, addr);
689 rprintf(FLOG, "rsync %s %s from %s (%s)\n",
690 am_sender ? "on" : "to",
691 request, host, addr);
697 /* don't allow the logs to be flooded too fast */
698 if (verbose > lp_max_verbosity(i))
699 verbose = lp_max_verbosity(i);
702 if (protocol_version < 23
703 && (protocol_version == 22 || am_sender))
704 io_start_multiplex_out();
705 else if (!ret || err_msg) {
706 /* We have to get I/O multiplexing started so that we can
707 * get the error back to the client. This means getting
708 * the protocol setup finished first in later versions. */
709 setup_protocol(f_out, f_in);
711 /* Since we failed in our option parsing, we may not
712 * have finished parsing that the client sent us a
713 * --files-from option, so look for it manually.
714 * Without this, the socket would be in the wrong
715 * state for the upcoming error message. */
718 for (i = 0; i < argc; i++) {
719 if (strncmp(argv[i], "--files-from", 12) == 0) {
726 write_byte(f_out, 0);
728 io_start_multiplex_out();
731 if (!ret || err_msg) {
733 rwrite(FERROR, err_msg, strlen(err_msg), 0);
737 exit_cleanup(RERR_UNSUPPORTED);
740 if (lp_timeout(i) && lp_timeout(i) > io_timeout)
741 set_io_timeout(lp_timeout(i));
743 /* If we have some incoming/outgoing chmod changes, append them to
744 * any user-specified changes (making our changes have priority).
745 * We also get a pointer to just our changes so that a receiver
746 * process can use them separately if --perms wasn't specified. */
748 p = lp_outgoing_chmod(i);
750 p = lp_incoming_chmod(i);
751 if (*p && !(daemon_chmod_modes = parse_chmod(p, &chmod_modes))) {
752 rprintf(FLOG, "Invalid \"%sing chmod\" directive: %s\n",
753 am_sender ? "outgo" : "incom", p);
756 start_server(f_in, f_out, argc, argv);
761 /* send a list of available modules to the client. Don't list those
762 with "list = False". */
763 static void send_listing(int fd)
765 int n = lp_numservices();
768 for (i = 0; i < n; i++) {
770 io_printf(fd, "%-15s\t%s\n", lp_name(i), lp_comment(i));
773 if (protocol_version >= 25)
774 io_printf(fd,"@RSYNCD: EXIT\n");
777 /* this is called when a connection is established to a client
778 and we want to start talking. The setup of the system is done from
780 int start_daemon(int f_in, int f_out)
786 io_set_sock_fds(f_in, f_out);
788 /* We must load the config file before calling any function that
789 * might cause log-file output to occur. This ensures that the
790 * "log file" param gets honored for the 2 non-forked use-cases
791 * (when rsync is run by init and run by a remote shell). */
792 if (!lp_load(config_file, 0))
793 exit_cleanup(RERR_SYNTAX);
795 addr = client_addr(f_in);
796 host = client_name(f_in);
797 rprintf(FLOG, "connect from %s (%s)\n", host, addr);
800 set_socket_options(f_in, "SO_KEEPALIVE");
802 set_socket_options(f_in, sockopts);
804 set_socket_options(f_in, lp_socket_options());
805 set_nonblocking(f_in);
808 if (exchange_protocols(f_in, f_out, line, sizeof line, 0) < 0)
812 if (!read_line_old(f_in, line, sizeof line))
815 if (!*line || strcmp(line, "#list") == 0) {
816 rprintf(FLOG, "module-list request from %s (%s)\n",
823 /* it's some sort of command that I don't understand */
824 io_printf(f_out, "@ERROR: Unknown command '%s'\n", line);
828 if ((i = lp_number(line)) < 0) {
829 rprintf(FLOG, "unknown module '%s' tried from %s (%s)\n",
831 io_printf(f_out, "@ERROR: Unknown module '%s'\n", line);
835 #ifdef HAVE_SIGACTION
836 sigact.sa_flags = SA_NOCLDSTOP;
838 SIGACTION(SIGCHLD, remember_children);
840 return rsync_module(f_in, f_out, i, addr, host);
843 int daemon_main(void)
847 if (is_a_socket(STDIN_FILENO)) {
850 /* we are running via inetd - close off stdout and
851 * stderr so that library functions (and getopt) don't
852 * try to use them. Redirect them to /dev/null */
853 for (i = 1; i < 3; i++) {
855 open("/dev/null", O_RDWR);
858 return start_daemon(STDIN_FILENO, STDIN_FILENO);
864 if (!lp_load(config_file, 1))
865 exit_cleanup(RERR_SYNTAX);
867 if (rsync_port == 0 && (rsync_port = lp_rsync_port()) == 0)
868 rsync_port = RSYNC_PORT;
869 if (bind_address == NULL && *lp_bind_address())
870 bind_address = lp_bind_address();
874 rprintf(FLOG, "rsyncd version %s starting, listening on port %d\n",
875 RSYNC_VERSION, rsync_port);
876 /* TODO: If listening on a particular address, then show that
877 * address too. In fact, why not just do inet_ntop on the
878 * local address??? */
880 if (((pid_file = lp_pid_file()) != NULL) && (*pid_file != '\0')) {
883 pid_t pid = getpid();
884 cleanup_set_pid(pid);
885 if ((fd = do_open(lp_pid_file(), O_WRONLY|O_CREAT|O_TRUNC,
886 0666 & ~orig_umask)) == -1) {
888 rsyserr(FLOG, errno, "failed to create pid file %s",
890 exit_cleanup(RERR_FILEIO);
892 snprintf(pidbuf, sizeof pidbuf, "%ld\n", (long)pid);
893 write(fd, pidbuf, strlen(pidbuf));
897 start_accept_loop(rsync_port, start_daemon);