2 * Copyright 2009 Oracle. All rights reserved.
4 * This file is part of nfs-utils.
6 * nfs-utils is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * nfs-utils is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with nfs-utils. If not, see <http://www.gnu.org/licenses/>.
23 * Callback information and NSM state is stored in files, usually
24 * under /var/lib/nfs. A database of information contained in local
25 * files stores NLM callback data and what remote peers to notify of
28 * For each monitored remote peer, a text file is created under the
29 * directory specified by NSM_MONITOR_DIR. The name of the file
30 * is a valid DNS hostname. The hostname string must be a valid
31 * ASCII DNS name, and must not contain slash characters, white space,
32 * or '\0' (ie. anything that might have some special meaning in a
35 * The contents of each file include seven blank-separated fields of
36 * text, finished with '\n'. The first field contains the network
37 * address of the NLM service to call back. The current implementation
38 * supports using only IPv4 addresses, so the only contents of this
39 * field are a network order IPv4 address expressed in 8 hexadecimal
42 * The next four fields are text strings of hexadecimal characters,
45 * 2. A 4 byte RPC program number of the NLM service to call back
46 * 3. A 4 byte RPC version number of the NLM service to call back
47 * 4. A 4 byte RPC procedure number of the NLM service to call back
48 * 5. A 16 byte opaque cookie that the NLM service uses to identify
51 * The sixth field is the monitored host's mon_name, passed to statd
52 * via an SM_MON request.
54 * The seventh field is the my_name for this peer, which is the
55 * hostname of the local NLM (currently on Linux, the result of
56 * `uname -n`). This can be used as the source address/hostname
57 * when sending SM_NOTIFY requests.
59 * The NSM protocol does not limit the contents of these strings
60 * in any way except that they must fit into 1024 bytes. Our
61 * implementation requires that these strings not contain
62 * white space or '\0'.
69 #include <sys/types.h>
88 #define RPCARGSLEN (4 * (8 + 1))
89 #define LINELEN (RPCARGSLEN + SM_PRIV_SIZE * 2 + 1)
91 #define NSM_KERNEL_STATE_FILE "/proc/sys/fs/nfs/nsm_local_state"
94 * Some distributions place statd's files in a subdirectory
96 #define NSM_PATH_EXTENSION
97 /* #define NSM_PATH_EXTENSION "/statd" */
99 #define NSM_DEFAULT_STATEDIR NFS_STATEDIR NSM_PATH_EXTENSION
101 static char nsm_base_dirname[PATH_MAX] = NSM_DEFAULT_STATEDIR;
103 #define NSM_MONITOR_DIR "sm"
104 #define NSM_NOTIFY_DIR "sm.bak"
105 #define NSM_STATE_FILE "state"
109 error_check(const int len, const size_t buflen)
111 return (len < 0) || ((size_t)len >= buflen);
115 exact_error_check(const ssize_t len, const size_t buflen)
117 return (len < 0) || ((size_t)len != buflen);
121 * Returns a dynamically allocated, '\0'-terminated buffer
122 * containing an appropriate pathname, or NULL if an error
123 * occurs. Caller must free the returned result with free(3).
127 nsm_make_record_pathname(const char *directory, const char *hostname)
135 * Block hostnames that contain characters that have
136 * meaning to the file system (like '/'), or that can
137 * be confusing on visual inspection (like ' ').
139 for (c = hostname; *c != '\0'; c++)
140 if (*c == '/' || isspace((int)*c) != 0) {
141 xlog(D_GENERAL, "Hostname contains invalid characters");
145 size = strlen(nsm_base_dirname) + strlen(directory) + strlen(hostname) + 3;
146 if (size > PATH_MAX) {
147 xlog(D_GENERAL, "Hostname results in pathname that is too long");
153 xlog(D_GENERAL, "Failed to allocate memory for pathname");
157 len = snprintf(path, size, "%s/%s/%s",
158 nsm_base_dirname, directory, hostname);
159 if (error_check(len, size)) {
160 xlog(D_GENERAL, "Pathname did not fit in specified buffer");
169 * Returns a dynamically allocated, '\0'-terminated buffer
170 * containing an appropriate pathname, or NULL if an error
171 * occurs. Caller must free the returned result with free(3).
175 nsm_make_pathname(const char *directory)
181 size = strlen(nsm_base_dirname) + strlen(directory) + 2;
189 len = snprintf(path, size, "%s/%s", nsm_base_dirname, directory);
190 if (error_check(len, size)) {
199 * Returns a dynamically allocated, '\0'-terminated buffer
200 * containing an appropriate pathname, or NULL if an error
201 * occurs. Caller must free the returned result with free(3).
205 nsm_make_temp_pathname(const char *pathname)
211 size = strlen(pathname) + sizeof(".new") + 2;
219 len = snprintf(path, size, "%s.new", pathname);
220 if (error_check(len, size)) {
229 * Use "mktemp, write, rename" to update the contents of a file atomically.
231 * Returns true if completely successful, or false if some error occurred.
234 nsm_atomic_write(const char *path, const void *buf, const size_t buflen)
236 _Bool result = false;
241 temp = nsm_make_temp_pathname(path);
243 xlog(L_ERROR, "Failed to create new path for %s", path);
247 fd = open(temp, O_CREAT | O_TRUNC | O_SYNC | O_WRONLY, 0644);
249 xlog(L_ERROR, "Failed to create %s: %m", temp);
253 len = write(fd, buf, buflen);
254 if (exact_error_check(len, buflen)) {
255 xlog(L_ERROR, "Failed to write %s: %m", temp);
261 if (close(fd) == -1) {
262 xlog(L_ERROR, "Failed to close %s: %m", temp);
267 if (rename(temp, path) == -1) {
268 xlog(L_ERROR, "Failed to rename %s -> %s: %m",
274 /* Ostensibly, a sync(2) is not needed here because
275 * open(O_CREAT), write(O_SYNC), and rename(2) are
276 * already synchronous with persistent storage, for
277 * any file system we care about. */
287 * nsm_setup_pathnames - set up pathname
288 * @progname: C string containing name of program, for error messages
289 * @parentdir: C string containing pathname to on-disk state, or NULL
291 * This runs before logging is set up, so error messages are directed
294 * Returns true and sets up our pathnames, if @parentdir was valid
295 * and usable; otherwise false is returned.
298 nsm_setup_pathnames(const char *progname, const char *parentdir)
300 static char buf[PATH_MAX];
304 /* First: test length of name and whether it exists */
305 if (lstat(parentdir, &st) == -1) {
306 (void)fprintf(stderr, "%s: Failed to stat %s: %s",
307 progname, parentdir, strerror(errno));
311 /* Ensure we have a clean directory pathname */
312 strncpy(buf, parentdir, sizeof(buf));
315 (void)fprintf(stderr, "%s: Unusable directory %s",
316 progname, parentdir);
320 xlog(D_CALL, "Using %s as the state directory", parentdir);
321 strncpy(nsm_base_dirname, parentdir, sizeof(nsm_base_dirname));
326 * nsm_is_default_parentdir - check if parent directory is default
328 * Returns true if the active statd parent directory, set by
329 * nsm_change_pathname(), is the same as the built-in default
330 * parent directory; otherwise false is returned.
333 nsm_is_default_parentdir(void)
335 return strcmp(nsm_base_dirname, NSM_DEFAULT_STATEDIR) == 0;
339 * nsm_drop_privileges - drop root privileges
340 * @pidfd: file descriptor of a pid file
342 * Returns true if successful, or false if some error occurred.
344 * Set our effective UID and GID to that of our on-disk database.
347 nsm_drop_privileges(const int pidfd)
351 (void)umask(S_IRWXO);
354 * XXX: If we can't stat dirname, or if dirname is owned by
355 * root, we should use "statduser" instead, which is set up
356 * by configure.ac. Nothing in nfs-utils seems to use
357 * "statduser," though.
359 if (lstat(nsm_base_dirname, &st) == -1) {
360 xlog(L_ERROR, "Failed to stat %s: %m", nsm_base_dirname);
364 if (st.st_uid == 0) {
365 xlog_warn("Running as root. "
366 "chown %s to choose different user", nsm_base_dirname);
370 if (chdir(nsm_base_dirname) == -1) {
371 xlog(L_ERROR, "Failed to change working directory to %s: %m",
377 * If the pidfile happens to reside on NFS, dropping privileges
378 * will probably cause us to lose access, even though we are
379 * holding it open. Chown it to prevent this.
382 if (fchown(pidfd, st.st_uid, st.st_gid) == -1)
383 xlog_warn("Failed to change owner of pidfile: %m");
385 if (setgroups(0, NULL) == -1) {
386 xlog(L_ERROR, "Failed to drop supplementary groups: %m");
393 * setgid(2) first, as setuid(2) may remove privileges needed
394 * to set the group id.
396 if (setgid(st.st_gid) == -1 || setuid(st.st_uid) == -1) {
397 xlog(L_ERROR, "Failed to drop privileges: %m");
401 xlog(D_CALL, "Effective UID, GID: %u, %u", st.st_uid, st.st_gid);
406 * nsm_get_state - retrieve on-disk NSM state number
408 * Returns an odd NSM state number read from disk, or an initial
409 * state number. Zero is returned if some error occurs.
412 nsm_get_state(_Bool update)
418 path = nsm_make_pathname(NSM_STATE_FILE);
420 xlog(L_ERROR, "Failed to allocate path for " NSM_STATE_FILE);
424 fd = open(path, O_RDONLY);
426 if (errno != ENOENT) {
427 xlog(L_ERROR, "Failed to open %s: %m", path);
431 xlog(L_NOTICE, "Initializing NSM state");
437 result = read(fd, &state, sizeof(state));
438 if (exact_error_check(result, sizeof(state))) {
439 xlog_warn("Failed to read %s: %m", path);
441 xlog(L_NOTICE, "Initializing NSM state");
447 if ((state & 1) == 0)
455 if (!nsm_atomic_write(path, &state, sizeof(state)))
465 * nsm_update_kernel_state - attempt to post new NSM state to kernel
466 * @state: NSM state number
470 nsm_update_kernel_state(const int state)
476 fd = open(NSM_KERNEL_STATE_FILE, O_WRONLY);
478 xlog(D_GENERAL, "Failed to open " NSM_KERNEL_STATE_FILE ": %m");
482 len = snprintf(buf, sizeof(buf), "%d", state);
483 if (error_check(len, sizeof(buf))) {
484 xlog_warn("Failed to form NSM state number string");
488 result = write(fd, buf, strlen(buf));
489 if (exact_error_check(result, strlen(buf)))
490 xlog_warn("Failed to write NSM state number: %m");
493 xlog(L_ERROR, "Failed to close NSM state file "
494 NSM_KERNEL_STATE_FILE ": %m");
498 * nsm_retire_monitored_hosts - back up all hosts from "sm/" to "sm.bak/"
500 * Returns the count of host records that were moved.
502 * Note that if any error occurs during this process, some monitor
503 * records may be left in the "sm" directory.
506 nsm_retire_monitored_hosts(void)
508 unsigned int count = 0;
513 path = nsm_make_pathname(NSM_MONITOR_DIR);
515 xlog(L_ERROR, "Failed to allocate path for " NSM_MONITOR_DIR);
522 xlog_warn("Failed to open " NSM_MONITOR_DIR ": %m");
526 while ((de = readdir(dir)) != NULL) {
529 if (de->d_type != (unsigned char)DT_REG)
531 if (de->d_name[0] == '.')
534 src = nsm_make_record_pathname(NSM_MONITOR_DIR, de->d_name);
536 xlog_warn("Bad monitor file name, skipping");
540 dst = nsm_make_record_pathname(NSM_NOTIFY_DIR, de->d_name);
543 xlog_warn("Bad notify file name, skipping");
547 if (rename(src, dst) == -1)
548 xlog_warn("Failed to rename %s -> %s: %m",
551 xlog(D_GENERAL, "Retired record for mon_name %s",
565 * nsm_priv_to_hex - convert a NSM private cookie to a hex string.
567 * @priv: buffer holding the binary NSM private cookie
568 * @buf: output buffer for NULL terminated hex string
569 * @buflen: size of output buffer
571 * Returns the length of the resulting string or 0 on error
574 nsm_priv_to_hex(const char *priv, char *buf, const size_t buflen)
577 size_t remaining = buflen;
579 for (i = 0; i < SM_PRIV_SIZE; i++) {
580 len = snprintf(buf, remaining, "%02x",
581 (unsigned int)(0xff & priv[i]));
582 if (error_check(len, remaining))
585 remaining -= (size_t)len;
588 return buflen - remaining;
592 * Returns the length in bytes of the created record.
594 __attribute_noinline__
596 nsm_create_monitor_record(char *buf, const size_t buflen,
597 const struct sockaddr *sap, const struct mon *m)
599 const struct sockaddr_in *sin = (const struct sockaddr_in *)sap;
600 size_t hexlen, remaining = buflen;
603 len = snprintf(buf, remaining, "%08x %08x %08x %08x ",
604 (unsigned int)sin->sin_addr.s_addr,
605 (unsigned int)m->mon_id.my_id.my_prog,
606 (unsigned int)m->mon_id.my_id.my_vers,
607 (unsigned int)m->mon_id.my_id.my_proc);
608 if (error_check(len, remaining))
611 remaining -= (size_t)len;
613 hexlen = nsm_priv_to_hex(m->priv, buf, remaining);
619 len = snprintf(buf, remaining, " %s %s\n",
620 m->mon_id.mon_name, m->mon_id.my_id.my_name);
621 if (error_check(len, remaining))
623 remaining -= (size_t)len;
625 return buflen - remaining;
629 nsm_append_monitored_host(const char *path, const char *line)
631 _Bool result = false;
638 if (stat(path, &stb) == -1) {
639 xlog(L_ERROR, "Failed to insert: "
640 "could not stat original file %s: %m", path);
643 buflen = (size_t)stb.st_size + strlen(line);
645 buf = malloc(buflen + 1);
647 xlog(L_ERROR, "Failed to insert: no memory");
650 memset(buf, 0, buflen + 1);
652 fd = open(path, O_RDONLY);
654 xlog(L_ERROR, "Failed to insert: "
655 "could not open original file %s: %m", path);
659 len = read(fd, buf, (size_t)stb.st_size);
660 if (exact_error_check(len, (size_t)stb.st_size)) {
661 xlog(L_ERROR, "Failed to insert: "
662 "could not read original file %s: %m", path);
670 if (nsm_atomic_write(path, buf, buflen))
679 * nsm_insert_monitored_host - write callback data for one host to disk
680 * @hostname: C string containing a hostname
681 * @sap: sockaddr containing NLM callback address
682 * @mon: SM_MON arguments to save
684 * Returns true if successful, otherwise false if some error occurs.
687 nsm_insert_monitored_host(const char *hostname, const struct sockaddr *sap,
690 static char buf[LINELEN + 1 + SM_MAXSTRLEN + 2];
692 _Bool result = false;
697 path = nsm_make_record_pathname(NSM_MONITOR_DIR, hostname);
699 xlog(L_ERROR, "Failed to insert: bad monitor hostname '%s'",
704 size = nsm_create_monitor_record(buf, sizeof(buf), sap, m);
706 xlog(L_ERROR, "Failed to insert: record too long");
711 * If exclusive create fails, we're adding a new line to an
714 fd = open(path, O_WRONLY | O_CREAT | O_EXCL | O_SYNC, S_IRUSR | S_IWUSR);
716 if (errno != EEXIST) {
717 xlog(L_ERROR, "Failed to insert: creating %s: %m", path);
721 result = nsm_append_monitored_host(path, buf);
726 len = write(fd, buf, size);
727 if (exact_error_check(len, size)) {
728 xlog_warn("Failed to insert: writing %s: %m", path);
733 if (close(fd) == -1) {
734 xlog(L_ERROR, "Failed to insert: closing %s: %m", path);
744 __attribute_noinline__
746 nsm_parse_line(char *line, struct sockaddr_in *sin, struct mon *m)
752 c = strchr(line, '\n');
756 count = sscanf(line, "%8x %8x %8x %8x ",
757 (unsigned int *)&sin->sin_addr.s_addr,
758 (unsigned int *)&m->mon_id.my_id.my_prog,
759 (unsigned int *)&m->mon_id.my_id.my_vers,
760 (unsigned int *)&m->mon_id.my_id.my_proc);
764 c = line + RPCARGSLEN;
765 for (i = 0; i < SM_PRIV_SIZE; i++) {
766 if (sscanf(c, "%2x", &tmp) != 1)
768 m->priv[i] = (char)tmp;
773 m->mon_id.mon_name = c;
774 while (*c != '\0' && *c != ' ')
780 m->mon_id.my_id.my_name = c;
786 * Stuff a 'struct mon' with callback data, and call @func.
788 * Returns the count of in-core records created.
791 nsm_read_line(const char *hostname, const time_t timestamp, char *line,
794 struct sockaddr_in sin = {
795 .sin_family = AF_INET,
799 if (!nsm_parse_line(line, &sin, &m))
802 return func(hostname, (struct sockaddr *)(char *)&sin, &m, timestamp);
806 * Given a filename, reads data from a file under NSM_MONITOR_DIR
807 * and invokes @func so caller can populate their in-core
808 * database with this data.
811 nsm_load_host(const char *directory, const char *filename, nsm_populate_t func)
813 char buf[LINELEN + 1 + SM_MAXSTRLEN + 2];
814 unsigned int result = 0;
819 path = nsm_make_record_pathname(directory, filename);
823 if (stat(path, &stb) == -1) {
824 xlog(L_ERROR, "Failed to stat %s: %m", path);
828 f = fopen(path, "r");
830 xlog(L_ERROR, "Failed to open %s: %m", path);
834 while (fgets(buf, (int)sizeof(buf), f) != NULL) {
835 buf[sizeof(buf) - 1] = '\0';
836 result += nsm_read_line(filename, stb.st_mtime, buf, func);
839 xlog(L_ERROR, "Failed to read monitor data from %s", path);
850 nsm_load_dir(const char *directory, nsm_populate_t func)
852 unsigned int count = 0;
857 path = nsm_make_pathname(directory);
859 xlog(L_ERROR, "Failed to allocate path for directory %s",
867 xlog(L_ERROR, "Failed to open directory %s: %m",
872 while ((de = readdir(dir)) != NULL) {
873 if (de->d_type != (unsigned char)DT_REG)
875 if (de->d_name[0] == '.')
878 count += nsm_load_host(directory, de->d_name, func);
886 * nsm_load_monitor_list - load list of hosts to monitor
887 * @func: callback function to create entry for one host
889 * Returns the count of hosts that were found in the directory.
892 nsm_load_monitor_list(nsm_populate_t func)
894 return nsm_load_dir(NSM_MONITOR_DIR, func);
898 * nsm_load_notify_list - load list of hosts to notify
899 * @func: callback function to create entry for one host
901 * Returns the count of hosts that were found in the directory.
904 nsm_load_notify_list(nsm_populate_t func)
906 return nsm_load_dir(NSM_NOTIFY_DIR, func);
910 nsm_delete_host(const char *directory, const char *hostname,
911 const char *mon_name, const char *my_name)
913 char line[LINELEN + 1 + SM_MAXSTRLEN + 2];
920 path = nsm_make_record_pathname(directory, hostname);
922 xlog(L_ERROR, "Bad filename, not deleting");
926 if (stat(path, &stb) == -1) {
927 xlog(L_ERROR, "Failed to delete: "
928 "could not stat original file %s: %m", path);
931 remaining = (size_t)stb.st_size + 1;
933 outbuf = malloc(remaining);
934 if (outbuf == NULL) {
935 xlog(L_ERROR, "Failed to delete: no memory");
939 f = fopen(path, "r");
941 xlog(L_ERROR, "Failed to delete: "
942 "could not open original file %s: %m", path);
947 * Walk the records in the file, and copy the non-matching
948 * ones to our output buffer.
951 while (fgets(line, (int)sizeof(line), f) != NULL) {
952 struct sockaddr_in sin;
956 if (!nsm_parse_line(line, &sin, &m)) {
957 xlog(L_ERROR, "Failed to delete: "
958 "could not parse original file %s", path);
963 if (strcmp(mon_name, m.mon_id.mon_name) == 0 &&
964 strcmp(my_name, m.mon_id.my_id.my_name) == 0)
967 /* nsm_parse_line destroys the contents of line[], so
968 * reconstruct the copy in our output buffer. */
969 len = nsm_create_monitor_record(next, remaining,
970 (struct sockaddr *)(char *)&sin, &m);
972 xlog(L_ERROR, "Failed to delete: "
973 "could not construct output record");
984 * If nothing was copied when we're done, then unlink the file.
985 * Otherwise, atomically update the contents of the file.
987 if (next != outbuf) {
988 if (!nsm_atomic_write(path, outbuf, strlen(outbuf)))
989 xlog(L_ERROR, "Failed to delete: "
990 "could not write new file %s: %m", path);
992 if (unlink(path) == -1)
993 xlog(L_ERROR, "Failed to delete: "
994 "could not unlink file %s: %m", path);
1003 * nsm_delete_monitored_host - delete on-disk record for monitored host
1004 * @hostname: '\0'-terminated C string containing hostname of record to delete
1005 * @mon_name: '\0'-terminated C string containing monname of record to delete
1006 * @my_name: '\0'-terminated C string containing myname of record to delete
1010 nsm_delete_monitored_host(const char *hostname, const char *mon_name,
1011 const char *my_name)
1013 nsm_delete_host(NSM_MONITOR_DIR, hostname, mon_name, my_name);
1017 * nsm_delete_notified_host - delete on-disk host record after notification
1018 * @hostname: '\0'-terminated C string containing hostname of record to delete
1019 * @mon_name: '\0'-terminated C string containing monname of record to delete
1020 * @my_name: '\0'-terminated C string containing myname of record to delete
1024 nsm_delete_notified_host(const char *hostname, const char *mon_name,
1025 const char *my_name)
1027 nsm_delete_host(NSM_NOTIFY_DIR, hostname, mon_name, my_name);