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 version 3 as
10 * published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, visit the http://fsf.org website.
25 extern int output_motd;
31 extern int rsync_port;
32 extern int ignore_errors;
33 extern int kluge_around_eof;
34 extern int daemon_over_rsh;
35 extern int sanitize_paths;
36 extern int filesfrom_fd;
37 extern int remote_protocol;
38 extern int protocol_version;
39 extern int io_timeout;
41 extern int default_af_hint;
42 extern int logfile_format_has_i;
43 extern int logfile_format_has_o_or_i;
44 extern mode_t orig_umask;
45 extern char *bind_address;
46 extern char *sockopts;
47 extern char *config_file;
48 extern char *logfile_format;
49 extern char *files_from;
51 extern struct chmod_mode_struct *chmod_modes;
52 extern struct filter_list_struct server_filter_list;
53 extern char curr_dir[];
58 struct chmod_mode_struct *daemon_chmod_modes;
60 /* module_dirlen is the length of the module_dir string when in daemon
61 * mode, not chrooted, and the path is not "/"; otherwise 0. */
62 char *module_dir = NULL;
63 unsigned int module_dirlen = 0;
66 static struct sigaction sigact;
70 * Run a client connected to an rsyncd. The alternative to this
71 * function for remote-shell connections is do_cmd().
73 * After negotiating which module to use and reading the server's
74 * motd, this hands over to client_run(). Telling the server the
75 * module will cause it to chroot/setuid/etc.
77 * Instead of doing a transfer, the client may at this stage instead
78 * get a listing of remote modules and exit.
80 * @return -1 for error in startup, or the result of client_run().
81 * Either way, it eventually gets passed to exit_cleanup().
83 int start_socket_client(char *host, char *path, int argc, char *argv[])
86 char *p, *user = NULL;
88 /* This is redundant with code in start_inband_exchange(), but this
89 * short-circuits a problem in the client before we open a socket,
90 * and the extra check won't hurt. */
93 "ERROR: The remote path must start with a module name not a /\n");
97 if ((p = strrchr(host, '@')) != NULL) {
103 fd = open_socket_out_wrapped(host, rsync_port, bind_address,
106 exit_cleanup(RERR_SOCKETIO);
108 set_socket_options(fd, sockopts);
110 ret = start_inband_exchange(user, path, fd, fd, argc);
112 return ret ? ret : client_run(fd, fd, -1, argc, argv);
115 int start_inband_exchange(const char *user, char *path, int f_in, int f_out,
119 char *sargs[MAX_ARGS];
121 char line[BIGPATHBUFLEN];
124 if (argc == 0 && !am_sender)
129 "ERROR: The remote path must start with a module name\n");
134 user = getenv("USER");
136 user = getenv("LOGNAME");
138 io_printf(f_out, "@RSYNCD: %d\n", protocol_version);
140 if (!read_line(f_in, line, sizeof line - 1)) {
141 rprintf(FERROR, "rsync: did not see server greeting\n");
145 if (sscanf(line,"@RSYNCD: %d", &remote_protocol) != 1) {
146 /* note that read_line strips of \n or \r */
147 rprintf(FERROR, "rsync: server sent \"%s\" rather than greeting\n",
151 if (protocol_version > remote_protocol)
152 protocol_version = remote_protocol;
154 if (list_only && protocol_version >= 29)
157 /* set daemon_over_rsh to false since we need to build the
158 * true set of args passed through the rsh/ssh connection;
159 * this is a no-op for direct-socket-connection mode */
161 server_options(sargs, &sargc);
163 sargs[sargc++] = ".";
166 sargs[sargc++] = path;
171 print_child_argv(sargs);
173 p = strchr(path,'/');
175 io_printf(f_out, "%s\n", path);
178 /* Old servers may just drop the connection here,
179 rather than sending a proper EXIT command. Yuck. */
180 kluge_around_eof = list_only && protocol_version < 25 ? 1 : 0;
183 if (!read_line(f_in, line, sizeof line - 1)) {
184 rprintf(FERROR, "rsync: didn't get server startup line\n");
188 if (strncmp(line,"@RSYNCD: AUTHREQD ",18) == 0) {
189 auth_client(f_out, user, line+18);
193 if (strcmp(line,"@RSYNCD: OK") == 0)
196 if (strcmp(line,"@RSYNCD: EXIT") == 0) {
197 /* This is sent by recent versions of the
198 * server to terminate the listing of modules.
199 * We don't want to go on and transfer
200 * anything; just exit. */
204 if (strncmp(line, "@ERROR", 6) == 0) {
205 rprintf(FERROR, "%s\n", line);
206 /* This is always fatal; the server will now
207 * close the socket. */
211 /* This might be a MOTD line or a module listing, but there is
212 * no way to differentiate it. The manpage mentions this. */
214 rprintf(FINFO, "%s\n", line);
216 kluge_around_eof = 0;
218 for (i = 0; i < sargc; i++) {
219 io_printf(f_out, "%s\n", sargs[i]);
221 io_printf(f_out, "\n");
223 if (protocol_version < 23) {
224 if (protocol_version == 22 || !am_sender)
225 io_start_multiplex_in();
231 static char *finish_pre_exec(pid_t pid, int fd, char *request,
232 int argc, char *argv[])
237 write_buf(fd, request, strlen(request)+1);
238 for (j = 0; j < argc; j++)
239 write_buf(fd, argv[j], strlen(argv[j])+1);
246 if (wait_process(pid, &status, 0) < 0
247 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
249 if (asprintf(&e, "pre-xfer exec returned failure (%d)%s%s\n",
250 status, status < 0 ? ": " : "",
251 status < 0 ? strerror(errno) : "") < 0)
252 out_of_memory("finish_pre_exec");
258 static int read_arg_from_pipe(int fd, char *buf, int limit)
260 char *bp = buf, *eob = buf + limit - 1;
263 if (read(fd, bp, 1) != 1)
275 static int rsync_module(int f_in, int f_out, int i, char *addr, char *host)
280 char line[BIGPATHBUFLEN];
281 uid_t uid = (uid_t)-2; /* canonically "nobody" */
282 gid_t gid = (gid_t)-2;
283 char *p, *err_msg = NULL;
284 char *name = lp_name(i);
285 int use_chroot = lp_use_chroot(i);
287 int ret, pre_exec_fd = -1;
288 pid_t pre_exec_pid = 0;
289 char *request = NULL;
291 if (!allow_access(addr, host, lp_hosts_allow(i), lp_hosts_deny(i))) {
292 rprintf(FLOG, "rsync denied on module %s from %s (%s)\n",
295 io_printf(f_out, "@ERROR: Unknown module '%s'\n", name);
298 "@ERROR: access denied to %s from %s (%s)\n",
304 if (am_daemon && am_server) {
305 rprintf(FLOG, "rsync allowed access on module %s from %s (%s)\n",
309 if (!claim_connection(lp_lock_file(i), lp_max_connections(i))) {
311 rsyserr(FLOG, errno, "failed to open lock file %s",
313 io_printf(f_out, "@ERROR: failed to open lock file\n");
315 rprintf(FLOG, "max connections (%d) reached\n",
316 lp_max_connections(i));
317 io_printf(f_out, "@ERROR: max connections (%d) reached -- try again later\n",
318 lp_max_connections(i));
323 auth_user = auth_server(f_in, f_out, i, host, addr, "@RSYNCD: AUTHREQD ");
326 io_printf(f_out, "@ERROR: auth failed on module %s\n", name);
335 if (lp_transfer_logging(i) && !logfile_format)
336 logfile_format = lp_log_format(i);
337 if (log_format_has(logfile_format, 'i'))
338 logfile_format_has_i = 1;
339 if (logfile_format_has_i || log_format_has(logfile_format, 'o'))
340 logfile_format_has_o_or_i = 1;
342 am_root = (MY_UID() == 0);
346 if (!name_to_uid(p, &uid)) {
348 rprintf(FLOG, "Invalid uid %s\n", p);
349 io_printf(f_out, "@ERROR: invalid uid %s\n", p);
356 if (!name_to_gid(p, &gid)) {
358 rprintf(FLOG, "Invalid gid %s\n", p);
359 io_printf(f_out, "@ERROR: invalid gid %s\n", p);
366 /* TODO: If we're not root, but the configuration requests
367 * that we change to some uid other than the current one, then
370 /* TODO: Perhaps take a list of gids, and make them into the
371 * supplementary groups. */
373 /* We do a push_dir() without actually calling chdir() in order
374 * to make sure that the module's path is absolute. After this
375 * check, module_dir will be set to an absolute path. */
376 module_dir = lp_path(i);
377 strlcpy(line, curr_dir, sizeof line);
378 if (!push_dir(module_dir, 1))
380 if (strcmp(curr_dir, module_dir) != 0)
381 module_dir = strdup(curr_dir);
382 push_dir(line, 1); /* Restore curr_dir. */
384 if (use_chroot || (module_dirlen = strlen(module_dir)) == 1) {
386 set_filter_dir("/", 1);
388 set_filter_dir(module_dir, module_dirlen);
391 parse_rule(&server_filter_list, p, MATCHFLG_WORD_SPLIT,
394 p = lp_include_from(i);
395 parse_filter_file(&server_filter_list, p, MATCHFLG_INCLUDE,
396 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES | XFLG_FATAL_ERRORS);
399 parse_rule(&server_filter_list, p,
400 MATCHFLG_INCLUDE | MATCHFLG_WORD_SPLIT,
401 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES);
403 p = lp_exclude_from(i);
404 parse_filter_file(&server_filter_list, p, 0,
405 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES | XFLG_FATAL_ERRORS);
408 parse_rule(&server_filter_list, p, MATCHFLG_WORD_SPLIT,
409 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES);
414 if (*lp_prexfer_exec(i) || *lp_postxfer_exec(i)) {
415 char *modname, *modpath, *hostaddr, *hostname, *username;
417 if (asprintf(&modname, "RSYNC_MODULE_NAME=%s", name) < 0
418 || asprintf(&modpath, "RSYNC_MODULE_PATH=%s", module_dir) < 0
419 || asprintf(&hostaddr, "RSYNC_HOST_ADDR=%s", addr) < 0
420 || asprintf(&hostname, "RSYNC_HOST_NAME=%s", host) < 0
421 || asprintf(&username, "RSYNC_USER_NAME=%s", auth_user) < 0)
422 out_of_memory("rsync_module");
429 /* For post-xfer exec, fork a new process to run the rsync
430 * daemon while this process waits for the exit status and
431 * runs the indicated command at that point. */
432 if (*lp_postxfer_exec(i)) {
435 rsyserr(FLOG, errno, "fork failed");
436 io_printf(f_out, "@ERROR: fork failed\n");
440 if (asprintf(&p, "RSYNC_PID=%ld", (long)pid) > 0)
442 if (wait_process(pid, &status, 0) < 0)
444 if (asprintf(&p, "RSYNC_RAW_STATUS=%d", status) > 0)
446 if (WIFEXITED(status))
447 status = WEXITSTATUS(status);
450 if (asprintf(&p, "RSYNC_EXIT_STATUS=%d", status) > 0)
452 system(lp_postxfer_exec(i));
456 /* For pre-xfer exec, fork a child process to run the indicated
457 * command, though it first waits for the parent process to
458 * send us the user's request via a pipe. */
459 if (*lp_prexfer_exec(i)) {
461 if (asprintf(&p, "RSYNC_PID=%ld", (long)getpid()) > 0)
463 if (pipe(fds) < 0 || (pre_exec_pid = fork()) < 0) {
464 rsyserr(FLOG, errno, "pre-xfer exec preparation failed");
465 io_printf(f_out, "@ERROR: pre-xfer exec preparation failed\n");
468 if (pre_exec_pid == 0) {
469 char buf[BIGPATHBUFLEN];
472 set_blocking(fds[0]);
473 len = read_arg_from_pipe(fds[0], buf, BIGPATHBUFLEN);
476 if (asprintf(&p, "RSYNC_REQUEST=%s", buf) > 0)
479 len = read_arg_from_pipe(fds[0], buf,
486 if (asprintf(&p, "RSYNC_ARG%d=%s", j, buf) > 0)
491 close(STDOUT_FILENO);
492 status = system(lp_prexfer_exec(i));
493 if (!WIFEXITED(status))
495 _exit(WEXITSTATUS(status));
498 set_blocking(fds[1]);
499 pre_exec_fd = fds[1];
507 * XXX: The 'use chroot' flag is a fairly reliable
508 * source of confusion, because it fails under two
509 * important circumstances: running as non-root,
510 * running on Win32 (or possibly others). On the
511 * other hand, if you are running as root, then it
512 * might be better to always use chroot.
514 * So, perhaps if we can't chroot we should just issue
515 * a warning, unless a "require chroot" flag is set,
516 * in which case we fail.
518 if (chroot(module_dir)) {
519 rsyserr(FLOG, errno, "chroot %s failed", module_dir);
520 io_printf(f_out, "@ERROR: chroot failed\n");
523 if (!push_dir("/", 0))
526 if (!push_dir(module_dir, 0)) {
528 rsyserr(FLOG, errno, "chdir %s failed\n", module_dir);
529 io_printf(f_out, "@ERROR: chdir failed\n");
536 /* XXXX: You could argue that if the daemon is started
537 * by a non-root user and they explicitly specify a
538 * gid, then we should try to change to that gid --
539 * this could be possible if it's already in their
540 * supplementary groups. */
542 /* TODO: Perhaps we need to document that if rsyncd is
543 * started by somebody other than root it will inherit
544 * all their supplementary groups. */
547 rsyserr(FLOG, errno, "setgid %d failed", (int)gid);
548 io_printf(f_out, "@ERROR: setgid failed\n");
551 #ifdef HAVE_SETGROUPS
552 /* Get rid of any supplementary groups this process
553 * might have inheristed. */
554 if (setgroups(1, &gid)) {
555 rsyserr(FLOG, errno, "setgroups failed");
556 io_printf(f_out, "@ERROR: setgroups failed\n");
562 rsyserr(FLOG, errno, "setuid %d failed", (int)uid);
563 io_printf(f_out, "@ERROR: setuid failed\n");
567 am_root = (MY_UID() == 0);
570 if (lp_temp_dir(i) && *lp_temp_dir(i)) {
571 tmpdir = lp_temp_dir(i);
572 if (strlen(tmpdir) >= MAXPATHLEN - 10) {
574 "the 'temp dir' value for %s is WAY too long -- ignoring.\n",
580 io_printf(f_out, "@RSYNCD: OK\n");
583 if (!(argv = new_array(char *, maxargs)))
584 out_of_memory("rsync_module");
585 argv[argc++] = "rsyncd";
588 if (!read_line(f_in, line, sizeof line - 1))
596 if (argc == maxargs) {
598 if (!(argv = realloc_array(argv, char *, maxargs)))
599 out_of_memory("rsync_module");
601 if (!(argv[argc] = strdup(p)))
602 out_of_memory("rsync_module");
604 switch (start_glob) {
607 if (strcmp(line, ".") == 0)
612 err_msg = finish_pre_exec(pre_exec_pid,
622 glob_expand(name, &argv, &argc, &maxargs);
628 err_msg = finish_pre_exec(pre_exec_pid, pre_exec_fd, request,
632 verbose = 0; /* future verbosity is controlled by client options */
633 ret = parse_arguments(&argc, (const char ***) &argv, 0);
634 am_server = 1; /* Don't let someone try to be tricky. */
635 if (lp_ignore_errors(module_id))
638 if (lp_fake_super(i))
640 else if (am_root < 0) /* Treat --fake-super from client as --super. */
643 if (filesfrom_fd == 0)
648 rprintf(FLOG, "rsync %s %s from %s@%s (%s)\n",
649 am_sender ? "on" : "to",
650 request, auth_user, host, addr);
652 rprintf(FLOG, "rsync %s %s from %s (%s)\n",
653 am_sender ? "on" : "to",
654 request, host, addr);
660 /* don't allow the logs to be flooded too fast */
661 if (verbose > lp_max_verbosity(i))
662 verbose = lp_max_verbosity(i);
665 if (protocol_version < 23
666 && (protocol_version == 22 || am_sender))
667 io_start_multiplex_out();
668 else if (!ret || err_msg) {
669 /* We have to get I/O multiplexing started so that we can
670 * get the error back to the client. This means getting
671 * the protocol setup finished first in later versions. */
672 setup_protocol(f_out, f_in);
674 /* Since we failed in our option parsing, we may not
675 * have finished parsing that the client sent us a
676 * --files-from option, so look for it manually.
677 * Without this, the socket would be in the wrong
678 * state for the upcoming error message. */
681 for (i = 0; i < argc; i++) {
682 if (strncmp(argv[i], "--files-from", 12) == 0) {
689 write_byte(f_out, 0);
691 io_start_multiplex_out();
694 if (!ret || err_msg) {
696 rwrite(FERROR, err_msg, strlen(err_msg), 0);
700 exit_cleanup(RERR_UNSUPPORTED);
703 if (lp_timeout(i) && lp_timeout(i) > io_timeout)
704 set_io_timeout(lp_timeout(i));
706 /* If we have some incoming/outgoing chmod changes, append them to
707 * any user-specified changes (making our changes have priority).
708 * We also get a pointer to just our changes so that a receiver
709 * process can use them separately if --perms wasn't specified. */
711 p = lp_outgoing_chmod(i);
713 p = lp_incoming_chmod(i);
714 if (*p && !(daemon_chmod_modes = parse_chmod(p, &chmod_modes))) {
715 rprintf(FLOG, "Invalid \"%sing chmod\" directive: %s\n",
716 am_sender ? "outgo" : "incom", p);
719 start_server(f_in, f_out, argc, argv);
724 /* send a list of available modules to the client. Don't list those
725 with "list = False". */
726 static void send_listing(int fd)
728 int n = lp_numservices();
731 for (i = 0; i < n; i++) {
733 io_printf(fd, "%-15s\t%s\n", lp_name(i), lp_comment(i));
736 if (protocol_version >= 25)
737 io_printf(fd,"@RSYNCD: EXIT\n");
740 /* this is called when a connection is established to a client
741 and we want to start talking. The setup of the system is done from
743 int start_daemon(int f_in, int f_out)
746 char *motd, *addr, *host;
749 io_set_sock_fds(f_in, f_out);
751 /* We must load the config file before calling any function that
752 * might cause log-file output to occur. This ensures that the
753 * "log file" param gets honored for the 2 non-forked use-cases
754 * (when rsync is run by init and run by a remote shell). */
755 if (!lp_load(config_file, 0))
756 exit_cleanup(RERR_SYNTAX);
758 addr = client_addr(f_in);
759 host = client_name(f_in);
760 rprintf(FLOG, "connect from %s (%s)\n", host, addr);
763 set_socket_options(f_in, "SO_KEEPALIVE");
765 set_socket_options(f_in, sockopts);
767 set_socket_options(f_in, lp_socket_options());
768 set_nonblocking(f_in);
771 io_printf(f_out, "@RSYNCD: %d\n", protocol_version);
773 motd = lp_motd_file();
775 FILE *f = fopen(motd,"r");
776 while (f && !feof(f)) {
777 int len = fread(line, 1, sizeof line - 1, f);
780 io_printf(f_out, "%s", line);
785 io_printf(f_out, "\n");
788 if (!read_line(f_in, line, sizeof line - 1))
791 if (sscanf(line,"@RSYNCD: %d", &remote_protocol) != 1) {
792 io_printf(f_out, "@ERROR: protocol startup error\n");
795 if (protocol_version > remote_protocol)
796 protocol_version = remote_protocol;
799 if (!read_line(f_in, line, sizeof line - 1))
802 if (!*line || strcmp(line, "#list") == 0) {
803 rprintf(FLOG, "module-list request from %s (%s)\n",
810 /* it's some sort of command that I don't understand */
811 io_printf(f_out, "@ERROR: Unknown command '%s'\n", line);
815 if ((i = lp_number(line)) < 0) {
816 rprintf(FLOG, "unknown module '%s' tried from %s (%s)\n",
818 io_printf(f_out, "@ERROR: Unknown module '%s'\n", line);
822 #ifdef HAVE_SIGACTION
823 sigact.sa_flags = SA_NOCLDSTOP;
825 SIGACTION(SIGCHLD, remember_children);
827 return rsync_module(f_in, f_out, i, addr, host);
830 int daemon_main(void)
834 if (is_a_socket(STDIN_FILENO)) {
837 /* we are running via inetd - close off stdout and
838 * stderr so that library functions (and getopt) don't
839 * try to use them. Redirect them to /dev/null */
840 for (i = 1; i < 3; i++) {
842 open("/dev/null", O_RDWR);
845 return start_daemon(STDIN_FILENO, STDIN_FILENO);
851 if (!lp_load(config_file, 1))
852 exit_cleanup(RERR_SYNTAX);
854 if (rsync_port == 0 && (rsync_port = lp_rsync_port()) == 0)
855 rsync_port = RSYNC_PORT;
856 if (bind_address == NULL && *lp_bind_address())
857 bind_address = lp_bind_address();
861 rprintf(FLOG, "rsyncd version %s starting, listening on port %d\n",
862 RSYNC_VERSION, rsync_port);
863 /* TODO: If listening on a particular address, then show that
864 * address too. In fact, why not just do inet_ntop on the
865 * local address??? */
867 if (((pid_file = lp_pid_file()) != NULL) && (*pid_file != '\0')) {
870 pid_t pid = getpid();
871 cleanup_set_pid(pid);
872 if ((fd = do_open(lp_pid_file(), O_WRONLY|O_CREAT|O_TRUNC,
873 0666 & ~orig_umask)) == -1) {
875 rsyserr(FLOG, errno, "failed to create pid file %s",
877 exit_cleanup(RERR_FILEIO);
879 snprintf(pidbuf, sizeof pidbuf, "%ld\n", (long)pid);
880 write(fd, pidbuf, strlen(pidbuf));
884 start_accept_loop(rsync_port, start_daemon);