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.
26 extern int output_motd;
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;
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;
52 extern struct chmod_mode_struct *chmod_modes;
53 extern struct filter_list_struct server_filter_list;
54 extern char curr_dir[];
59 struct chmod_mode_struct *daemon_chmod_modes;
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;
66 static int rl_nulls = 0;
69 static struct sigaction sigact;
73 * Run a client connected to an rsyncd. The alternative to this
74 * function for remote-shell connections is do_cmd().
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.
80 * Instead of doing a transfer, the client may at this stage instead
81 * get a listing of remote modules and exit.
83 * @return -1 for error in startup, or the result of client_run().
84 * Either way, it eventually gets passed to exit_cleanup().
86 int start_socket_client(char *host, int remote_argc, char *remote_argv[],
87 int argc, char *argv[])
90 char *p, *user = NULL;
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 == '/') {
97 "ERROR: The remote path must start with a module name not a /\n");
101 if ((p = strrchr(host, '@')) != NULL) {
107 fd = open_socket_out_wrapped(host, rsync_port, bind_address,
110 exit_cleanup(RERR_SOCKETIO);
112 set_socket_options(fd, sockopts);
114 ret = start_inband_exchange(fd, fd, user, remote_argc, remote_argv);
116 return ret ? ret : client_run(fd, fd, -1, argc, argv);
119 static int exchange_protocols(int f_in, int f_out, char *buf, size_t bufsiz, int am_client)
122 #if SUBPROTOCOL_VERSION != 0
123 int our_sub = protocol_version < PROTOCOL_VERSION ? 0 : SUBPROTOCOL_VERSION;
129 io_printf(f_out, "@RSYNCD: %d.%d\n", protocol_version, our_sub);
132 motd = lp_motd_file();
134 FILE *f = fopen(motd,"r");
135 while (f && !feof(f)) {
136 int len = fread(buf, 1, bufsiz - 1, f);
138 write_buf(f_out, buf, len);
142 write_sbuf(f_out, "\n");
146 /* This strips the \n. */
147 if (!read_line_old(f_in, buf, bufsiz)) {
149 rprintf(FERROR, "rsync: did not see server greeting\n");
153 if (sscanf(buf, "@RSYNCD: %d.%d", &remote_protocol, &remote_sub) < 1) {
155 rprintf(FERROR, "rsync: server sent \"%s\" rather than greeting\n", buf);
157 io_printf(f_out, "@ERROR: protocol startup error\n");
161 if (remote_sub < 0) {
162 if (remote_protocol == 30) {
164 rprintf(FERROR, "rsync: server is speaking an incompatible beta of protocol 30\n");
166 io_printf(f_out, "@ERROR: your client is speaking an incompatible beta of protocol 30\n");
172 if (protocol_version > remote_protocol) {
173 protocol_version = remote_protocol;
176 } else if (protocol_version == remote_protocol) {
177 if (remote_sub != our_sub)
180 #if SUBPROTOCOL_VERSION != 0
181 else if (protocol_version < remote_protocol) {
187 if (protocol_version >= 30)
193 int start_inband_exchange(int f_in, int f_out, const char *user, int argc, char *argv[])
196 char line[BIGPATHBUFLEN];
197 char *sargs[MAX_ARGS];
199 char *p, *path = *argv;
201 if (argc == 0 && !am_sender)
206 "ERROR: The remote path must start with a module name\n");
211 user = getenv("USER");
213 user = getenv("LOGNAME");
215 if (exchange_protocols(f_in, f_out, line, sizeof line, 1) < 0)
218 if (list_only && protocol_version >= 29)
221 /* set daemon_over_rsh to false since we need to build the
222 * true set of args passed through the rsh/ssh connection;
223 * this is a no-op for direct-socket-connection mode */
225 server_options(sargs, &sargc);
227 if (sargc >= MAX_ARGS - 2)
230 sargs[sargc++] = ".";
233 if (sargc >= MAX_ARGS - 1) {
235 rprintf(FERROR, "internal: args[] overflowed in do_cmd()\n");
236 exit_cleanup(RERR_SYNTAX);
238 sargs[sargc++] = *argv++;
245 print_child_argv(sargs);
247 p = strchr(path, '/');
249 io_printf(f_out, "%s\n", path);
252 /* Old servers may just drop the connection here,
253 rather than sending a proper EXIT command. Yuck. */
254 kluge_around_eof = list_only && protocol_version < 25 ? 1 : 0;
257 if (!read_line_old(f_in, line, sizeof line)) {
258 rprintf(FERROR, "rsync: didn't get server startup line\n");
262 if (strncmp(line,"@RSYNCD: AUTHREQD ",18) == 0) {
263 auth_client(f_out, user, line+18);
267 if (strcmp(line,"@RSYNCD: OK") == 0)
270 if (strcmp(line,"@RSYNCD: EXIT") == 0) {
271 /* This is sent by recent versions of the
272 * server to terminate the listing of modules.
273 * We don't want to go on and transfer
274 * anything; just exit. */
278 if (strncmp(line, "@ERROR", 6) == 0) {
279 rprintf(FERROR, "%s\n", line);
280 /* This is always fatal; the server will now
281 * close the socket. */
285 /* This might be a MOTD line or a module listing, but there is
286 * no way to differentiate it. The manpage mentions this. */
288 rprintf(FINFO, "%s\n", line);
290 kluge_around_eof = 0;
293 for (i = 0; i < sargc; i++) {
294 write_sbuf(f_out, sargs[i]);
295 write_byte(f_out, 0);
297 write_byte(f_out, 0);
299 for (i = 0; i < sargc; i++)
300 io_printf(f_out, "%s\n", sargs[i]);
301 write_sbuf(f_out, "\n");
304 if (protocol_version < 23) {
305 if (protocol_version == 22 || !am_sender)
306 io_start_multiplex_in();
312 static char *finish_pre_exec(pid_t pid, int fd, char *request,
313 int argc, char *argv[])
320 write_buf(fd, request, strlen(request)+1);
321 for (j = 0; j < argc; j++)
322 write_buf(fd, argv[j], strlen(argv[j])+1);
327 if (wait_process(pid, &status, 0) < 0
328 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
330 if (asprintf(&e, "pre-xfer exec returned failure (%d)%s%s\n",
331 status, status < 0 ? ": " : "",
332 status < 0 ? strerror(errno) : "") < 0)
333 out_of_memory("finish_pre_exec");
339 static int read_arg_from_pipe(int fd, char *buf, int limit)
341 char *bp = buf, *eob = buf + limit - 1;
344 if (read(fd, bp, 1) != 1)
356 static int rsync_module(int f_in, int f_out, int i, char *addr, char *host)
360 char line[BIGPATHBUFLEN];
361 uid_t uid = (uid_t)-2; /* canonically "nobody" */
362 gid_t gid = (gid_t)-2;
363 char *p, *err_msg = NULL;
364 char *name = lp_name(i);
365 int use_chroot = lp_use_chroot(i);
366 int ret, pre_exec_fd = -1;
367 pid_t pre_exec_pid = 0;
368 char *request = NULL;
370 if (!allow_access(addr, host, lp_hosts_allow(i), lp_hosts_deny(i))) {
371 rprintf(FLOG, "rsync denied on module %s from %s (%s)\n",
374 io_printf(f_out, "@ERROR: Unknown module '%s'\n", name);
377 "@ERROR: access denied to %s from %s (%s)\n",
383 if (am_daemon && am_server) {
384 rprintf(FLOG, "rsync allowed access on module %s from %s (%s)\n",
388 if (!claim_connection(lp_lock_file(i), lp_max_connections(i))) {
390 rsyserr(FLOG, errno, "failed to open lock file %s",
392 io_printf(f_out, "@ERROR: failed to open lock file\n");
394 rprintf(FLOG, "max connections (%d) reached\n",
395 lp_max_connections(i));
396 io_printf(f_out, "@ERROR: max connections (%d) reached -- try again later\n",
397 lp_max_connections(i));
402 auth_user = auth_server(f_in, f_out, i, host, addr, "@RSYNCD: AUTHREQD ");
405 io_printf(f_out, "@ERROR: auth failed on module %s\n", name);
414 if (lp_transfer_logging(i) && !logfile_format)
415 logfile_format = lp_log_format(i);
416 if (log_format_has(logfile_format, 'i'))
417 logfile_format_has_i = 1;
418 if (logfile_format_has_i || log_format_has(logfile_format, 'o'))
419 logfile_format_has_o_or_i = 1;
421 am_root = (MY_UID() == 0);
425 if (!name_to_uid(p, &uid)) {
427 rprintf(FLOG, "Invalid uid %s\n", p);
428 io_printf(f_out, "@ERROR: invalid uid %s\n", p);
435 if (!name_to_gid(p, &gid)) {
437 rprintf(FLOG, "Invalid gid %s\n", p);
438 io_printf(f_out, "@ERROR: invalid gid %s\n", p);
445 /* TODO: If we're not root, but the configuration requests
446 * that we change to some uid other than the current one, then
449 /* TODO: Perhaps take a list of gids, and make them into the
450 * supplementary groups. */
452 /* We do a push_dir() without actually calling chdir() in order
453 * to make sure that the module's path is absolute. After this
454 * check, module_dir will be set to an absolute path. */
455 module_dir = lp_path(i);
456 strlcpy(line, curr_dir, sizeof line);
457 if (!push_dir(module_dir, 1))
459 if (strcmp(curr_dir, module_dir) != 0)
460 module_dir = strdup(curr_dir);
461 push_dir(line, 1); /* Restore curr_dir. */
463 if (use_chroot || (module_dirlen = strlen(module_dir)) == 1) {
465 set_filter_dir("/", 1);
467 set_filter_dir(module_dir, module_dirlen);
470 parse_rule(&server_filter_list, p, MATCHFLG_WORD_SPLIT,
473 p = lp_include_from(i);
474 parse_filter_file(&server_filter_list, p, MATCHFLG_INCLUDE,
475 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES | XFLG_FATAL_ERRORS);
478 parse_rule(&server_filter_list, p,
479 MATCHFLG_INCLUDE | MATCHFLG_WORD_SPLIT,
480 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES);
482 p = lp_exclude_from(i);
483 parse_filter_file(&server_filter_list, p, 0,
484 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES | XFLG_FATAL_ERRORS);
487 parse_rule(&server_filter_list, p, MATCHFLG_WORD_SPLIT,
488 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES);
493 if (*lp_prexfer_exec(i) || *lp_postxfer_exec(i)) {
494 char *modname, *modpath, *hostaddr, *hostname, *username;
496 if (asprintf(&modname, "RSYNC_MODULE_NAME=%s", name) < 0
497 || asprintf(&modpath, "RSYNC_MODULE_PATH=%s", module_dir) < 0
498 || asprintf(&hostaddr, "RSYNC_HOST_ADDR=%s", addr) < 0
499 || asprintf(&hostname, "RSYNC_HOST_NAME=%s", host) < 0
500 || asprintf(&username, "RSYNC_USER_NAME=%s", auth_user) < 0)
501 out_of_memory("rsync_module");
508 /* For post-xfer exec, fork a new process to run the rsync
509 * daemon while this process waits for the exit status and
510 * runs the indicated command at that point. */
511 if (*lp_postxfer_exec(i)) {
514 rsyserr(FLOG, errno, "fork failed");
515 io_printf(f_out, "@ERROR: fork failed\n");
519 if (asprintf(&p, "RSYNC_PID=%ld", (long)pid) > 0)
521 if (wait_process(pid, &status, 0) < 0)
523 if (asprintf(&p, "RSYNC_RAW_STATUS=%d", status) > 0)
525 if (WIFEXITED(status))
526 status = WEXITSTATUS(status);
529 if (asprintf(&p, "RSYNC_EXIT_STATUS=%d", status) > 0)
531 system(lp_postxfer_exec(i));
535 /* For pre-xfer exec, fork a child process to run the indicated
536 * command, though it first waits for the parent process to
537 * send us the user's request via a pipe. */
538 if (*lp_prexfer_exec(i)) {
540 if (asprintf(&p, "RSYNC_PID=%ld", (long)getpid()) > 0)
542 if (pipe(fds) < 0 || (pre_exec_pid = fork()) < 0) {
543 rsyserr(FLOG, errno, "pre-xfer exec preparation failed");
544 io_printf(f_out, "@ERROR: pre-xfer exec preparation failed\n");
547 if (pre_exec_pid == 0) {
548 char buf[BIGPATHBUFLEN];
551 set_blocking(fds[0]);
552 len = read_arg_from_pipe(fds[0], buf, BIGPATHBUFLEN);
555 if (asprintf(&p, "RSYNC_REQUEST=%s", buf) > 0)
558 len = read_arg_from_pipe(fds[0], buf,
565 if (asprintf(&p, "RSYNC_ARG%d=%s", j, buf) > 0)
570 close(STDOUT_FILENO);
571 status = system(lp_prexfer_exec(i));
572 if (!WIFEXITED(status))
574 _exit(WEXITSTATUS(status));
577 set_blocking(fds[1]);
578 pre_exec_fd = fds[1];
586 * XXX: The 'use chroot' flag is a fairly reliable
587 * source of confusion, because it fails under two
588 * important circumstances: running as non-root,
589 * running on Win32 (or possibly others). On the
590 * other hand, if you are running as root, then it
591 * might be better to always use chroot.
593 * So, perhaps if we can't chroot we should just issue
594 * a warning, unless a "require chroot" flag is set,
595 * in which case we fail.
597 if (chroot(module_dir)) {
598 rsyserr(FLOG, errno, "chroot %s failed", module_dir);
599 io_printf(f_out, "@ERROR: chroot failed\n");
602 if (!push_dir("/", 0))
605 if (!push_dir(module_dir, 0)) {
607 rsyserr(FLOG, errno, "chdir %s failed\n", module_dir);
608 io_printf(f_out, "@ERROR: chdir failed\n");
615 /* XXXX: You could argue that if the daemon is started
616 * by a non-root user and they explicitly specify a
617 * gid, then we should try to change to that gid --
618 * this could be possible if it's already in their
619 * supplementary groups. */
621 /* TODO: Perhaps we need to document that if rsyncd is
622 * started by somebody other than root it will inherit
623 * all their supplementary groups. */
626 rsyserr(FLOG, errno, "setgid %d failed", (int)gid);
627 io_printf(f_out, "@ERROR: setgid failed\n");
630 #ifdef HAVE_SETGROUPS
631 /* Get rid of any supplementary groups this process
632 * might have inheristed. */
633 if (setgroups(1, &gid)) {
634 rsyserr(FLOG, errno, "setgroups failed");
635 io_printf(f_out, "@ERROR: setgroups failed\n");
641 rsyserr(FLOG, errno, "setuid %d failed", (int)uid);
642 io_printf(f_out, "@ERROR: setuid failed\n");
646 am_root = (MY_UID() == 0);
649 if (lp_temp_dir(i) && *lp_temp_dir(i)) {
650 tmpdir = lp_temp_dir(i);
651 if (strlen(tmpdir) >= MAXPATHLEN - 10) {
653 "the 'temp dir' value for %s is WAY too long -- ignoring.\n",
659 io_printf(f_out, "@RSYNCD: OK\n");
661 opt_cnt = read_args(f_in, name, line, sizeof line, rl_nulls, &argv, &argc, &request);
664 err_msg = finish_pre_exec(pre_exec_pid, pre_exec_fd, request,
668 verbose = 0; /* future verbosity is controlled by client options */
669 ret = parse_arguments(&argc, (const char ***) &argv, 0);
670 am_server = 1; /* Don't let someone try to be tricky. */
671 if (lp_ignore_errors(module_id))
674 if (lp_fake_super(i))
676 else if (am_root < 0) /* Treat --fake-super from client as --super. */
679 if (filesfrom_fd == 0)
684 rprintf(FLOG, "rsync %s %s from %s@%s (%s)\n",
685 am_sender ? "on" : "to",
686 request, auth_user, host, addr);
688 rprintf(FLOG, "rsync %s %s from %s (%s)\n",
689 am_sender ? "on" : "to",
690 request, host, addr);
696 /* don't allow the logs to be flooded too fast */
697 if (verbose > lp_max_verbosity(i))
698 verbose = lp_max_verbosity(i);
701 if (protocol_version < 23
702 && (protocol_version == 22 || am_sender))
703 io_start_multiplex_out();
704 else if (!ret || err_msg) {
705 /* We have to get I/O multiplexing started so that we can
706 * get the error back to the client. This means getting
707 * the protocol setup finished first in later versions. */
708 setup_protocol(f_out, f_in);
710 /* Since we failed in our option parsing, we may not
711 * have finished parsing that the client sent us a
712 * --files-from option, so look for it manually.
713 * Without this, the socket would be in the wrong
714 * state for the upcoming error message. */
717 for (i = 0; i < argc; i++) {
718 if (strncmp(argv[i], "--files-from", 12) == 0) {
725 write_byte(f_out, 0);
727 io_start_multiplex_out();
730 if (!ret || err_msg) {
732 rwrite(FERROR, err_msg, strlen(err_msg), 0);
736 exit_cleanup(RERR_UNSUPPORTED);
739 if (lp_timeout(i) && lp_timeout(i) > io_timeout)
740 set_io_timeout(lp_timeout(i));
742 /* If we have some incoming/outgoing chmod changes, append them to
743 * any user-specified changes (making our changes have priority).
744 * We also get a pointer to just our changes so that a receiver
745 * process can use them separately if --perms wasn't specified. */
747 p = lp_outgoing_chmod(i);
749 p = lp_incoming_chmod(i);
750 if (*p && !(daemon_chmod_modes = parse_chmod(p, &chmod_modes))) {
751 rprintf(FLOG, "Invalid \"%sing chmod\" directive: %s\n",
752 am_sender ? "outgo" : "incom", p);
755 start_server(f_in, f_out, argc, argv);
760 /* send a list of available modules to the client. Don't list those
761 with "list = False". */
762 static void send_listing(int fd)
764 int n = lp_numservices();
767 for (i = 0; i < n; i++) {
769 io_printf(fd, "%-15s\t%s\n", lp_name(i), lp_comment(i));
772 if (protocol_version >= 25)
773 io_printf(fd,"@RSYNCD: EXIT\n");
776 /* this is called when a connection is established to a client
777 and we want to start talking. The setup of the system is done from
779 int start_daemon(int f_in, int f_out)
785 io_set_sock_fds(f_in, f_out);
787 /* We must load the config file before calling any function that
788 * might cause log-file output to occur. This ensures that the
789 * "log file" param gets honored for the 2 non-forked use-cases
790 * (when rsync is run by init and run by a remote shell). */
791 if (!lp_load(config_file, 0))
792 exit_cleanup(RERR_SYNTAX);
794 addr = client_addr(f_in);
795 host = client_name(f_in);
796 rprintf(FLOG, "connect from %s (%s)\n", host, addr);
799 set_socket_options(f_in, "SO_KEEPALIVE");
801 set_socket_options(f_in, sockopts);
803 set_socket_options(f_in, lp_socket_options());
804 set_nonblocking(f_in);
807 if (exchange_protocols(f_in, f_out, line, sizeof line, 0) < 0)
811 if (!read_line_old(f_in, line, sizeof line))
814 if (!*line || strcmp(line, "#list") == 0) {
815 rprintf(FLOG, "module-list request from %s (%s)\n",
822 /* it's some sort of command that I don't understand */
823 io_printf(f_out, "@ERROR: Unknown command '%s'\n", line);
827 if ((i = lp_number(line)) < 0) {
828 rprintf(FLOG, "unknown module '%s' tried from %s (%s)\n",
830 io_printf(f_out, "@ERROR: Unknown module '%s'\n", line);
834 #ifdef HAVE_SIGACTION
835 sigact.sa_flags = SA_NOCLDSTOP;
837 SIGACTION(SIGCHLD, remember_children);
839 return rsync_module(f_in, f_out, i, addr, host);
842 int daemon_main(void)
846 if (is_a_socket(STDIN_FILENO)) {
849 /* we are running via inetd - close off stdout and
850 * stderr so that library functions (and getopt) don't
851 * try to use them. Redirect them to /dev/null */
852 for (i = 1; i < 3; i++) {
854 open("/dev/null", O_RDWR);
857 return start_daemon(STDIN_FILENO, STDIN_FILENO);
863 if (!lp_load(config_file, 1))
864 exit_cleanup(RERR_SYNTAX);
866 if (rsync_port == 0 && (rsync_port = lp_rsync_port()) == 0)
867 rsync_port = RSYNC_PORT;
868 if (bind_address == NULL && *lp_bind_address())
869 bind_address = lp_bind_address();
873 rprintf(FLOG, "rsyncd version %s starting, listening on port %d\n",
874 RSYNC_VERSION, rsync_port);
875 /* TODO: If listening on a particular address, then show that
876 * address too. In fact, why not just do inet_ntop on the
877 * local address??? */
879 if (((pid_file = lp_pid_file()) != NULL) && (*pid_file != '\0')) {
882 pid_t pid = getpid();
883 cleanup_set_pid(pid);
884 if ((fd = do_open(lp_pid_file(), O_WRONLY|O_CREAT|O_TRUNC,
885 0666 & ~orig_umask)) == -1) {
887 rsyserr(FLOG, errno, "failed to create pid file %s",
889 exit_cleanup(RERR_FILEIO);
891 snprintf(pidbuf, sizeof pidbuf, "%ld\n", (long)pid);
892 write(fd, pidbuf, strlen(pidbuf));
896 start_accept_loop(rsync_port, start_daemon);