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;
67 static struct sigaction sigact;
71 * Run a client connected to an rsyncd. The alternative to this
72 * function for remote-shell connections is do_cmd().
74 * After negotiating which module to use and reading the server's
75 * motd, this hands over to client_run(). Telling the server the
76 * module will cause it to chroot/setuid/etc.
78 * Instead of doing a transfer, the client may at this stage instead
79 * get a listing of remote modules and exit.
81 * @return -1 for error in startup, or the result of client_run().
82 * Either way, it eventually gets passed to exit_cleanup().
84 int start_socket_client(char *host, char *path, int argc, char *argv[])
87 char *p, *user = NULL;
89 /* This is redundant with code in start_inband_exchange(), but this
90 * short-circuits a problem in the client before we open a socket,
91 * and the extra check won't hurt. */
94 "ERROR: The remote path must start with a module name not a /\n");
98 if ((p = strrchr(host, '@')) != NULL) {
104 fd = open_socket_out_wrapped(host, rsync_port, bind_address,
107 exit_cleanup(RERR_SOCKETIO);
109 set_socket_options(fd, sockopts);
111 ret = start_inband_exchange(user, path, fd, fd, argc);
113 return ret ? ret : client_run(fd, fd, -1, argc, argv);
116 int start_inband_exchange(const char *user, char *path, int f_in, int f_out,
120 char *sargs[MAX_ARGS];
122 char line[BIGPATHBUFLEN];
125 if (argc == 0 && !am_sender)
130 "ERROR: The remote path must start with a module name\n");
135 user = getenv("USER");
137 user = getenv("LOGNAME");
139 io_printf(f_out, "@RSYNCD: %d\n", protocol_version);
141 if (!read_line(f_in, line, sizeof line - 1)) {
142 rprintf(FERROR, "rsync: did not see server greeting\n");
146 if (sscanf(line,"@RSYNCD: %d", &remote_protocol) != 1) {
147 /* note that read_line strips of \n or \r */
148 rprintf(FERROR, "rsync: server sent \"%s\" rather than greeting\n",
152 if (protocol_version > remote_protocol)
153 protocol_version = remote_protocol;
155 if (list_only && protocol_version >= 29)
158 /* set daemon_over_rsh to false since we need to build the
159 * true set of args passed through the rsh/ssh connection;
160 * this is a no-op for direct-socket-connection mode */
162 server_options(sargs, &sargc);
164 sargs[sargc++] = ".";
167 sargs[sargc++] = path;
172 print_child_argv(sargs);
174 p = strchr(path,'/');
176 io_printf(f_out, "%s\n", path);
179 /* Old servers may just drop the connection here,
180 rather than sending a proper EXIT command. Yuck. */
181 kluge_around_eof = list_only && protocol_version < 25 ? 1 : 0;
184 if (!read_line(f_in, line, sizeof line - 1)) {
185 rprintf(FERROR, "rsync: didn't get server startup line\n");
189 if (strncmp(line,"@RSYNCD: AUTHREQD ",18) == 0) {
190 auth_client(f_out, user, line+18);
194 if (strcmp(line,"@RSYNCD: OK") == 0)
197 if (strcmp(line,"@RSYNCD: EXIT") == 0) {
198 /* This is sent by recent versions of the
199 * server to terminate the listing of modules.
200 * We don't want to go on and transfer
201 * anything; just exit. */
205 if (strncmp(line, "@ERROR", 6) == 0) {
206 rprintf(FERROR, "%s\n", line);
207 /* This is always fatal; the server will now
208 * close the socket. */
212 /* This might be a MOTD line or a module listing, but there is
213 * no way to differentiate it. The manpage mentions this. */
215 rprintf(FINFO, "%s\n", line);
217 kluge_around_eof = 0;
219 for (i = 0; i < sargc; i++) {
220 io_printf(f_out, "%s\n", sargs[i]);
222 io_printf(f_out, "\n");
224 if (protocol_version < 23) {
225 if (protocol_version == 22 || !am_sender)
226 io_start_multiplex_in();
232 static char *finish_pre_exec(pid_t pid, int fd, char *request,
233 int argc, char *argv[])
238 write_buf(fd, request, strlen(request)+1);
239 for (j = 0; j < argc; j++)
240 write_buf(fd, argv[j], strlen(argv[j])+1);
247 if (wait_process(pid, &status, 0) < 0
248 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
250 if (asprintf(&e, "pre-xfer exec returned failure (%d)%s%s\n",
251 status, status < 0 ? ": " : "",
252 status < 0 ? strerror(errno) : "") < 0)
253 out_of_memory("finish_pre_exec");
259 static int read_arg_from_pipe(int fd, char *buf, int limit)
261 char *bp = buf, *eob = buf + limit - 1;
264 if (read(fd, bp, 1) != 1)
276 static int rsync_module(int f_in, int f_out, int i, char *addr, char *host)
281 char line[BIGPATHBUFLEN];
282 uid_t uid = (uid_t)-2; /* canonically "nobody" */
283 gid_t gid = (gid_t)-2;
284 char *p, *err_msg = NULL;
285 char *name = lp_name(i);
286 int use_chroot = lp_use_chroot(i);
288 int ret, pre_exec_fd = -1;
289 pid_t pre_exec_pid = 0;
290 char *request = NULL;
292 if (!allow_access(addr, host, lp_hosts_allow(i), lp_hosts_deny(i))) {
293 rprintf(FLOG, "rsync denied on module %s from %s (%s)\n",
296 io_printf(f_out, "@ERROR: Unknown module '%s'\n", name);
299 "@ERROR: access denied to %s from %s (%s)\n",
305 if (am_daemon && am_server) {
306 rprintf(FLOG, "rsync allowed access on module %s from %s (%s)\n",
310 if (!claim_connection(lp_lock_file(i), lp_max_connections(i))) {
312 rsyserr(FLOG, errno, "failed to open lock file %s",
314 io_printf(f_out, "@ERROR: failed to open lock file\n");
316 rprintf(FLOG, "max connections (%d) reached\n",
317 lp_max_connections(i));
318 io_printf(f_out, "@ERROR: max connections (%d) reached -- try again later\n",
319 lp_max_connections(i));
324 auth_user = auth_server(f_in, f_out, i, host, addr, "@RSYNCD: AUTHREQD ");
327 io_printf(f_out, "@ERROR: auth failed on module %s\n", name);
336 if (lp_transfer_logging(i) && !logfile_format)
337 logfile_format = lp_log_format(i);
338 if (log_format_has(logfile_format, 'i'))
339 logfile_format_has_i = 1;
340 if (logfile_format_has_i || log_format_has(logfile_format, 'o'))
341 logfile_format_has_o_or_i = 1;
343 am_root = (MY_UID() == 0);
347 if (!name_to_uid(p, &uid)) {
349 rprintf(FLOG, "Invalid uid %s\n", p);
350 io_printf(f_out, "@ERROR: invalid uid %s\n", p);
357 if (!name_to_gid(p, &gid)) {
359 rprintf(FLOG, "Invalid gid %s\n", p);
360 io_printf(f_out, "@ERROR: invalid gid %s\n", p);
367 /* TODO: If we're not root, but the configuration requests
368 * that we change to some uid other than the current one, then
371 /* TODO: Perhaps take a list of gids, and make them into the
372 * supplementary groups. */
374 /* We do a push_dir() without actually calling chdir() in order
375 * to make sure that the module's path is absolute. After this
376 * check, module_dir will be set to an absolute path. */
377 module_dir = lp_path(i);
378 strlcpy(line, curr_dir, sizeof line);
379 if (!push_dir(module_dir, 1))
381 if (strcmp(curr_dir, module_dir) != 0)
382 module_dir = strdup(curr_dir);
383 push_dir(line, 1); /* Restore curr_dir. */
385 if (use_chroot || (module_dirlen = strlen(module_dir)) == 1) {
387 set_filter_dir("/", 1);
389 set_filter_dir(module_dir, module_dirlen);
392 parse_rule(&server_filter_list, p, MATCHFLG_WORD_SPLIT,
395 p = lp_include_from(i);
396 parse_filter_file(&server_filter_list, p, MATCHFLG_INCLUDE,
397 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES | XFLG_FATAL_ERRORS);
400 parse_rule(&server_filter_list, p,
401 MATCHFLG_INCLUDE | MATCHFLG_WORD_SPLIT,
402 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES);
404 p = lp_exclude_from(i);
405 parse_filter_file(&server_filter_list, p, 0,
406 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES | XFLG_FATAL_ERRORS);
409 parse_rule(&server_filter_list, p, MATCHFLG_WORD_SPLIT,
410 XFLG_ABS_IF_SLASH | XFLG_OLD_PREFIXES);
415 if (*lp_prexfer_exec(i) || *lp_postxfer_exec(i)) {
416 char *modname, *modpath, *hostaddr, *hostname, *username;
418 if (asprintf(&modname, "RSYNC_MODULE_NAME=%s", name) < 0
419 || asprintf(&modpath, "RSYNC_MODULE_PATH=%s", module_dir) < 0
420 || asprintf(&hostaddr, "RSYNC_HOST_ADDR=%s", addr) < 0
421 || asprintf(&hostname, "RSYNC_HOST_NAME=%s", host) < 0
422 || asprintf(&username, "RSYNC_USER_NAME=%s", auth_user) < 0)
423 out_of_memory("rsync_module");
430 /* For post-xfer exec, fork a new process to run the rsync
431 * daemon while this process waits for the exit status and
432 * runs the indicated command at that point. */
433 if (*lp_postxfer_exec(i)) {
436 rsyserr(FLOG, errno, "fork failed");
437 io_printf(f_out, "@ERROR: fork failed\n");
441 if (asprintf(&p, "RSYNC_PID=%ld", (long)pid) > 0)
443 if (wait_process(pid, &status, 0) < 0)
445 if (asprintf(&p, "RSYNC_RAW_STATUS=%d", status) > 0)
447 if (WIFEXITED(status))
448 status = WEXITSTATUS(status);
451 if (asprintf(&p, "RSYNC_EXIT_STATUS=%d", status) > 0)
453 system(lp_postxfer_exec(i));
457 /* For pre-xfer exec, fork a child process to run the indicated
458 * command, though it first waits for the parent process to
459 * send us the user's request via a pipe. */
460 if (*lp_prexfer_exec(i)) {
462 if (asprintf(&p, "RSYNC_PID=%ld", (long)getpid()) > 0)
464 if (pipe(fds) < 0 || (pre_exec_pid = fork()) < 0) {
465 rsyserr(FLOG, errno, "pre-xfer exec preparation failed");
466 io_printf(f_out, "@ERROR: pre-xfer exec preparation failed\n");
469 if (pre_exec_pid == 0) {
470 char buf[BIGPATHBUFLEN];
473 set_blocking(fds[0]);
474 len = read_arg_from_pipe(fds[0], buf, BIGPATHBUFLEN);
477 if (asprintf(&p, "RSYNC_REQUEST=%s", buf) > 0)
480 len = read_arg_from_pipe(fds[0], buf,
487 if (asprintf(&p, "RSYNC_ARG%d=%s", j, buf) > 0)
492 close(STDOUT_FILENO);
493 status = system(lp_prexfer_exec(i));
494 if (!WIFEXITED(status))
496 _exit(WEXITSTATUS(status));
499 set_blocking(fds[1]);
500 pre_exec_fd = fds[1];
508 * XXX: The 'use chroot' flag is a fairly reliable
509 * source of confusion, because it fails under two
510 * important circumstances: running as non-root,
511 * running on Win32 (or possibly others). On the
512 * other hand, if you are running as root, then it
513 * might be better to always use chroot.
515 * So, perhaps if we can't chroot we should just issue
516 * a warning, unless a "require chroot" flag is set,
517 * in which case we fail.
519 if (chroot(module_dir)) {
520 rsyserr(FLOG, errno, "chroot %s failed", module_dir);
521 io_printf(f_out, "@ERROR: chroot failed\n");
524 if (!push_dir("/", 0))
527 if (!push_dir(module_dir, 0)) {
529 rsyserr(FLOG, errno, "chdir %s failed\n", module_dir);
530 io_printf(f_out, "@ERROR: chdir failed\n");
537 /* XXXX: You could argue that if the daemon is started
538 * by a non-root user and they explicitly specify a
539 * gid, then we should try to change to that gid --
540 * this could be possible if it's already in their
541 * supplementary groups. */
543 /* TODO: Perhaps we need to document that if rsyncd is
544 * started by somebody other than root it will inherit
545 * all their supplementary groups. */
548 rsyserr(FLOG, errno, "setgid %d failed", (int)gid);
549 io_printf(f_out, "@ERROR: setgid failed\n");
552 #ifdef HAVE_SETGROUPS
553 /* Get rid of any supplementary groups this process
554 * might have inheristed. */
555 if (setgroups(1, &gid)) {
556 rsyserr(FLOG, errno, "setgroups failed");
557 io_printf(f_out, "@ERROR: setgroups failed\n");
563 rsyserr(FLOG, errno, "setuid %d failed", (int)uid);
564 io_printf(f_out, "@ERROR: setuid failed\n");
568 am_root = (MY_UID() == 0);
571 if (lp_temp_dir(i) && *lp_temp_dir(i)) {
572 tmpdir = lp_temp_dir(i);
573 if (strlen(tmpdir) >= MAXPATHLEN - 10) {
575 "the 'temp dir' value for %s is WAY too long -- ignoring.\n",
581 io_printf(f_out, "@RSYNCD: OK\n");
584 if (!(argv = new_array(char *, maxargs)))
585 out_of_memory("rsync_module");
586 argv[argc++] = "rsyncd";
589 if (!read_line(f_in, line, sizeof line - 1))
597 if (argc == maxargs) {
599 if (!(argv = realloc_array(argv, char *, maxargs)))
600 out_of_memory("rsync_module");
602 if (!(argv[argc] = strdup(p)))
603 out_of_memory("rsync_module");
605 switch (start_glob) {
608 if (strcmp(line, ".") == 0)
613 err_msg = finish_pre_exec(pre_exec_pid,
623 glob_expand(name, &argv, &argc, &maxargs);
629 err_msg = finish_pre_exec(pre_exec_pid, pre_exec_fd, request,
633 verbose = 0; /* future verbosity is controlled by client options */
634 ret = parse_arguments(&argc, (const char ***) &argv, 0);
635 am_server = 1; /* Don't let someone try to be tricky. */
636 if (lp_ignore_errors(module_id))
639 if (lp_fake_super(i))
641 else if (am_root < 0) /* Treat --fake-super from client as --super. */
644 if (filesfrom_fd == 0)
649 rprintf(FLOG, "rsync %s %s from %s@%s (%s)\n",
650 am_sender ? "on" : "to",
651 request, auth_user, host, addr);
653 rprintf(FLOG, "rsync %s %s from %s (%s)\n",
654 am_sender ? "on" : "to",
655 request, host, addr);
661 /* don't allow the logs to be flooded too fast */
662 if (verbose > lp_max_verbosity(i))
663 verbose = lp_max_verbosity(i);
666 if (protocol_version < 23
667 && (protocol_version == 22 || am_sender))
668 io_start_multiplex_out();
669 else if (!ret || err_msg) {
670 /* We have to get I/O multiplexing started so that we can
671 * get the error back to the client. This means getting
672 * the protocol setup finished first in later versions. */
673 setup_protocol(f_out, f_in);
675 /* Since we failed in our option parsing, we may not
676 * have finished parsing that the client sent us a
677 * --files-from option, so look for it manually.
678 * Without this, the socket would be in the wrong
679 * state for the upcoming error message. */
682 for (i = 0; i < argc; i++) {
683 if (strncmp(argv[i], "--files-from", 12) == 0) {
690 write_byte(f_out, 0);
692 io_start_multiplex_out();
695 if (!ret || err_msg) {
697 rwrite(FERROR, err_msg, strlen(err_msg), 0);
701 exit_cleanup(RERR_UNSUPPORTED);
704 if (lp_timeout(i) && lp_timeout(i) > io_timeout)
705 set_io_timeout(lp_timeout(i));
707 /* If we have some incoming/outgoing chmod changes, append them to
708 * any user-specified changes (making our changes have priority).
709 * We also get a pointer to just our changes so that a receiver
710 * process can use them separately if --perms wasn't specified. */
712 p = lp_outgoing_chmod(i);
714 p = lp_incoming_chmod(i);
715 if (*p && !(daemon_chmod_modes = parse_chmod(p, &chmod_modes))) {
716 rprintf(FLOG, "Invalid \"%sing chmod\" directive: %s\n",
717 am_sender ? "outgo" : "incom", p);
720 start_server(f_in, f_out, argc, argv);
725 /* send a list of available modules to the client. Don't list those
726 with "list = False". */
727 static void send_listing(int fd)
729 int n = lp_numservices();
732 for (i = 0; i < n; i++) {
734 io_printf(fd, "%-15s\t%s\n", lp_name(i), lp_comment(i));
737 if (protocol_version >= 25)
738 io_printf(fd,"@RSYNCD: EXIT\n");
741 /* this is called when a connection is established to a client
742 and we want to start talking. The setup of the system is done from
744 int start_daemon(int f_in, int f_out)
747 char *motd, *addr, *host;
750 io_set_sock_fds(f_in, f_out);
752 /* We must load the config file before calling any function that
753 * might cause log-file output to occur. This ensures that the
754 * "log file" param gets honored for the 2 non-forked use-cases
755 * (when rsync is run by init and run by a remote shell). */
756 if (!lp_load(config_file, 0))
757 exit_cleanup(RERR_SYNTAX);
759 addr = client_addr(f_in);
760 host = client_name(f_in);
761 rprintf(FLOG, "connect from %s (%s)\n", host, addr);
764 set_socket_options(f_in, "SO_KEEPALIVE");
766 set_socket_options(f_in, sockopts);
768 set_socket_options(f_in, lp_socket_options());
769 set_nonblocking(f_in);
772 io_printf(f_out, "@RSYNCD: %d\n", protocol_version);
774 motd = lp_motd_file();
776 FILE *f = fopen(motd,"r");
777 while (f && !feof(f)) {
778 int len = fread(line, 1, sizeof line - 1, f);
781 io_printf(f_out, "%s", line);
786 io_printf(f_out, "\n");
789 if (!read_line(f_in, line, sizeof line - 1))
792 if (sscanf(line,"@RSYNCD: %d", &remote_protocol) != 1) {
793 io_printf(f_out, "@ERROR: protocol startup error\n");
796 if (protocol_version > remote_protocol)
797 protocol_version = remote_protocol;
800 if (!read_line(f_in, line, sizeof line - 1))
803 if (!*line || strcmp(line, "#list") == 0) {
804 rprintf(FLOG, "module-list request from %s (%s)\n",
811 /* it's some sort of command that I don't understand */
812 io_printf(f_out, "@ERROR: Unknown command '%s'\n", line);
816 if ((i = lp_number(line)) < 0) {
817 rprintf(FLOG, "unknown module '%s' tried from %s (%s)\n",
819 io_printf(f_out, "@ERROR: Unknown module '%s'\n", line);
823 #ifdef HAVE_SIGACTION
824 sigact.sa_flags = SA_NOCLDSTOP;
826 SIGACTION(SIGCHLD, remember_children);
828 return rsync_module(f_in, f_out, i, addr, host);
831 int daemon_main(void)
835 if (is_a_socket(STDIN_FILENO)) {
838 /* we are running via inetd - close off stdout and
839 * stderr so that library functions (and getopt) don't
840 * try to use them. Redirect them to /dev/null */
841 for (i = 1; i < 3; i++) {
843 open("/dev/null", O_RDWR);
846 return start_daemon(STDIN_FILENO, STDIN_FILENO);
852 if (!lp_load(config_file, 1))
853 exit_cleanup(RERR_SYNTAX);
855 if (rsync_port == 0 && (rsync_port = lp_rsync_port()) == 0)
856 rsync_port = RSYNC_PORT;
857 if (bind_address == NULL && *lp_bind_address())
858 bind_address = lp_bind_address();
862 rprintf(FLOG, "rsyncd version %s starting, listening on port %d\n",
863 RSYNC_VERSION, rsync_port);
864 /* TODO: If listening on a particular address, then show that
865 * address too. In fact, why not just do inet_ntop on the
866 * local address??? */
868 if (((pid_file = lp_pid_file()) != NULL) && (*pid_file != '\0')) {
871 pid_t pid = getpid();
872 cleanup_set_pid(pid);
873 if ((fd = do_open(lp_pid_file(), O_WRONLY|O_CREAT|O_TRUNC,
874 0666 & ~orig_umask)) == -1) {
876 rsyserr(FLOG, errno, "failed to create pid file %s",
878 exit_cleanup(RERR_FILEIO);
880 snprintf(pidbuf, sizeof pidbuf, "%ld\n", (long)pid);
881 write(fd, pidbuf, strlen(pidbuf));
885 start_accept_loop(rsync_port, start_daemon);