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>
70 #include <sys/capability.h>
71 #include <sys/prctl.h>
90 #define RPCARGSLEN (4 * (8 + 1))
91 #define LINELEN (RPCARGSLEN + SM_PRIV_SIZE * 2 + 1)
93 #define NSM_KERNEL_STATE_FILE "/proc/sys/fs/nfs/nsm_local_state"
96 * Some distributions place statd's files in a subdirectory
98 #define NSM_PATH_EXTENSION
99 /* #define NSM_PATH_EXTENSION "/statd" */
101 #define NSM_DEFAULT_STATEDIR NFS_STATEDIR NSM_PATH_EXTENSION
103 static char nsm_base_dirname[PATH_MAX] = NSM_DEFAULT_STATEDIR;
105 #define NSM_MONITOR_DIR "sm"
106 #define NSM_NOTIFY_DIR "sm.bak"
107 #define NSM_STATE_FILE "state"
111 error_check(const int len, const size_t buflen)
113 return (len < 0) || ((size_t)len >= buflen);
117 exact_error_check(const ssize_t len, const size_t buflen)
119 return (len < 0) || ((size_t)len != buflen);
123 * Returns a dynamically allocated, '\0'-terminated buffer
124 * containing an appropriate pathname, or NULL if an error
125 * occurs. Caller must free the returned result with free(3).
129 nsm_make_record_pathname(const char *directory, const char *hostname)
137 * Block hostnames that contain characters that have
138 * meaning to the file system (like '/'), or that can
139 * be confusing on visual inspection (like ' ').
141 for (c = hostname; *c != '\0'; c++)
142 if (*c == '/' || isspace((int)*c) != 0) {
143 xlog(D_GENERAL, "Hostname contains invalid characters");
147 size = strlen(nsm_base_dirname) + strlen(directory) + strlen(hostname) + 3;
148 if (size > PATH_MAX) {
149 xlog(D_GENERAL, "Hostname results in pathname that is too long");
155 xlog(D_GENERAL, "Failed to allocate memory for pathname");
159 len = snprintf(path, size, "%s/%s/%s",
160 nsm_base_dirname, directory, hostname);
161 if (error_check(len, size)) {
162 xlog(D_GENERAL, "Pathname did not fit in specified buffer");
171 * Returns a dynamically allocated, '\0'-terminated buffer
172 * containing an appropriate pathname, or NULL if an error
173 * occurs. Caller must free the returned result with free(3).
177 nsm_make_pathname(const char *directory)
183 size = strlen(nsm_base_dirname) + strlen(directory) + 2;
191 len = snprintf(path, size, "%s/%s", nsm_base_dirname, directory);
192 if (error_check(len, size)) {
201 * Returns a dynamically allocated, '\0'-terminated buffer
202 * containing an appropriate pathname, or NULL if an error
203 * occurs. Caller must free the returned result with free(3).
207 nsm_make_temp_pathname(const char *pathname)
213 size = strlen(pathname) + sizeof(".new") + 2;
221 len = snprintf(path, size, "%s.new", pathname);
222 if (error_check(len, size)) {
231 * Use "mktemp, write, rename" to update the contents of a file atomically.
233 * Returns true if completely successful, or false if some error occurred.
236 nsm_atomic_write(const char *path, const void *buf, const size_t buflen)
238 _Bool result = false;
243 temp = nsm_make_temp_pathname(path);
245 xlog(L_ERROR, "Failed to create new path for %s", path);
249 fd = open(temp, O_CREAT | O_TRUNC | O_SYNC | O_WRONLY, 0644);
251 xlog(L_ERROR, "Failed to create %s: %m", temp);
255 len = write(fd, buf, buflen);
256 if (exact_error_check(len, buflen)) {
257 xlog(L_ERROR, "Failed to write %s: %m", temp);
263 if (close(fd) == -1) {
264 xlog(L_ERROR, "Failed to close %s: %m", temp);
269 if (rename(temp, path) == -1) {
270 xlog(L_ERROR, "Failed to rename %s -> %s: %m",
276 /* Ostensibly, a sync(2) is not needed here because
277 * open(O_CREAT), write(O_SYNC), and rename(2) are
278 * already synchronous with persistent storage, for
279 * any file system we care about. */
289 * nsm_setup_pathnames - set up pathname
290 * @progname: C string containing name of program, for error messages
291 * @parentdir: C string containing pathname to on-disk state, or NULL
293 * This runs before logging is set up, so error messages are directed
296 * Returns true and sets up our pathnames, if @parentdir was valid
297 * and usable; otherwise false is returned.
300 nsm_setup_pathnames(const char *progname, const char *parentdir)
302 static char buf[PATH_MAX];
306 /* First: test length of name and whether it exists */
307 if (lstat(parentdir, &st) == -1) {
308 (void)fprintf(stderr, "%s: Failed to stat %s: %s",
309 progname, parentdir, strerror(errno));
313 /* Ensure we have a clean directory pathname */
314 strncpy(buf, parentdir, sizeof(buf));
317 (void)fprintf(stderr, "%s: Unusable directory %s",
318 progname, parentdir);
322 xlog(D_CALL, "Using %s as the state directory", parentdir);
323 strncpy(nsm_base_dirname, parentdir, sizeof(nsm_base_dirname));
328 * nsm_is_default_parentdir - check if parent directory is default
330 * Returns true if the active statd parent directory, set by
331 * nsm_change_pathname(), is the same as the built-in default
332 * parent directory; otherwise false is returned.
335 nsm_is_default_parentdir(void)
337 return strcmp(nsm_base_dirname, NSM_DEFAULT_STATEDIR) == 0;
341 * Clear all capabilities but CAP_NET_BIND_SERVICE. This permits
342 * callers to acquire privileged source ports, but all other root
343 * capabilities are disallowed.
345 * Returns true if successful, or false if some error occurred.
348 nsm_clear_capabilities(void)
352 caps = cap_from_text("cap_net_bind_service=ep");
354 xlog(L_ERROR, "Failed to allocate capability: %m");
358 if (cap_set_proc(caps) == -1) {
359 xlog(L_ERROR, "Failed to set capability flags: %m");
360 (void)cap_free(caps);
364 (void)cap_free(caps);
369 * nsm_drop_privileges - drop root privileges
370 * @pidfd: file descriptor of a pid file
372 * Returns true if successful, or false if some error occurred.
374 * Set our effective UID and GID to that of our on-disk database.
377 nsm_drop_privileges(const int pidfd)
381 (void)umask(S_IRWXO);
384 * XXX: If we can't stat dirname, or if dirname is owned by
385 * root, we should use "statduser" instead, which is set up
386 * by configure.ac. Nothing in nfs-utils seems to use
387 * "statduser," though.
389 if (lstat(nsm_base_dirname, &st) == -1) {
390 xlog(L_ERROR, "Failed to stat %s: %m", nsm_base_dirname);
394 if (st.st_uid == 0) {
395 xlog_warn("Running as root. "
396 "chown %s to choose different user", nsm_base_dirname);
400 if (chdir(nsm_base_dirname) == -1) {
401 xlog(L_ERROR, "Failed to change working directory to %s: %m",
407 * If the pidfile happens to reside on NFS, dropping privileges
408 * will probably cause us to lose access, even though we are
409 * holding it open. Chown it to prevent this.
412 if (fchown(pidfd, st.st_uid, st.st_gid) == -1)
413 xlog_warn("Failed to change owner of pidfile: %m");
416 * Don't clear capabilities when dropping root.
418 if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) == -1) {
419 xlog(L_ERROR, "prctl(PR_SET_KEEPCAPS) failed: %m");
423 if (setgroups(0, NULL) == -1) {
424 xlog(L_ERROR, "Failed to drop supplementary groups: %m");
431 * setgid(2) first, as setuid(2) may remove privileges needed
432 * to set the group id.
434 if (setgid(st.st_gid) == -1 || setuid(st.st_uid) == -1) {
435 xlog(L_ERROR, "Failed to drop privileges: %m");
439 xlog(D_CALL, "Effective UID, GID: %u, %u", st.st_uid, st.st_gid);
441 return nsm_clear_capabilities();
445 * nsm_get_state - retrieve on-disk NSM state number
447 * Returns an odd NSM state number read from disk, or an initial
448 * state number. Zero is returned if some error occurs.
451 nsm_get_state(_Bool update)
457 path = nsm_make_pathname(NSM_STATE_FILE);
459 xlog(L_ERROR, "Failed to allocate path for " NSM_STATE_FILE);
463 fd = open(path, O_RDONLY);
465 if (errno != ENOENT) {
466 xlog(L_ERROR, "Failed to open %s: %m", path);
470 xlog(L_NOTICE, "Initializing NSM state");
476 result = read(fd, &state, sizeof(state));
477 if (exact_error_check(result, sizeof(state))) {
478 xlog_warn("Failed to read %s: %m", path);
480 xlog(L_NOTICE, "Initializing NSM state");
486 if ((state & 1) == 0)
494 if (!nsm_atomic_write(path, &state, sizeof(state)))
504 * nsm_update_kernel_state - attempt to post new NSM state to kernel
505 * @state: NSM state number
509 nsm_update_kernel_state(const int state)
515 fd = open(NSM_KERNEL_STATE_FILE, O_WRONLY);
517 xlog(D_GENERAL, "Failed to open " NSM_KERNEL_STATE_FILE ": %m");
521 len = snprintf(buf, sizeof(buf), "%d", state);
522 if (error_check(len, sizeof(buf))) {
523 xlog_warn("Failed to form NSM state number string");
527 result = write(fd, buf, strlen(buf));
528 if (exact_error_check(result, strlen(buf)))
529 xlog_warn("Failed to write NSM state number: %m");
532 xlog(L_ERROR, "Failed to close NSM state file "
533 NSM_KERNEL_STATE_FILE ": %m");
537 * nsm_retire_monitored_hosts - back up all hosts from "sm/" to "sm.bak/"
539 * Returns the count of host records that were moved.
541 * Note that if any error occurs during this process, some monitor
542 * records may be left in the "sm" directory.
545 nsm_retire_monitored_hosts(void)
547 unsigned int count = 0;
552 path = nsm_make_pathname(NSM_MONITOR_DIR);
554 xlog(L_ERROR, "Failed to allocate path for " NSM_MONITOR_DIR);
561 xlog_warn("Failed to open " NSM_MONITOR_DIR ": %m");
565 while ((de = readdir(dir)) != NULL) {
568 if (de->d_type != (unsigned char)DT_REG)
570 if (de->d_name[0] == '.')
573 src = nsm_make_record_pathname(NSM_MONITOR_DIR, de->d_name);
575 xlog_warn("Bad monitor file name, skipping");
579 dst = nsm_make_record_pathname(NSM_NOTIFY_DIR, de->d_name);
582 xlog_warn("Bad notify file name, skipping");
586 if (rename(src, dst) == -1)
587 xlog_warn("Failed to rename %s -> %s: %m",
590 xlog(D_GENERAL, "Retired record for mon_name %s",
604 * nsm_priv_to_hex - convert a NSM private cookie to a hex string.
606 * @priv: buffer holding the binary NSM private cookie
607 * @buf: output buffer for NULL terminated hex string
608 * @buflen: size of output buffer
610 * Returns the length of the resulting string or 0 on error
613 nsm_priv_to_hex(const char *priv, char *buf, const size_t buflen)
616 size_t remaining = buflen;
618 for (i = 0; i < SM_PRIV_SIZE; i++) {
619 len = snprintf(buf, remaining, "%02x",
620 (unsigned int)(0xff & priv[i]));
621 if (error_check(len, remaining))
624 remaining -= (size_t)len;
627 return buflen - remaining;
631 * Returns the length in bytes of the created record.
633 __attribute_noinline__
635 nsm_create_monitor_record(char *buf, const size_t buflen,
636 const struct sockaddr *sap, const struct mon *m)
638 const struct sockaddr_in *sin = (const struct sockaddr_in *)sap;
639 size_t hexlen, remaining = buflen;
642 len = snprintf(buf, remaining, "%08x %08x %08x %08x ",
643 (unsigned int)sin->sin_addr.s_addr,
644 (unsigned int)m->mon_id.my_id.my_prog,
645 (unsigned int)m->mon_id.my_id.my_vers,
646 (unsigned int)m->mon_id.my_id.my_proc);
647 if (error_check(len, remaining))
650 remaining -= (size_t)len;
652 hexlen = nsm_priv_to_hex(m->priv, buf, remaining);
658 len = snprintf(buf, remaining, " %s %s\n",
659 m->mon_id.mon_name, m->mon_id.my_id.my_name);
660 if (error_check(len, remaining))
662 remaining -= (size_t)len;
664 return buflen - remaining;
668 nsm_append_monitored_host(const char *path, const char *line)
670 _Bool result = false;
677 if (stat(path, &stb) == -1) {
678 xlog(L_ERROR, "Failed to insert: "
679 "could not stat original file %s: %m", path);
682 buflen = (size_t)stb.st_size + strlen(line);
684 buf = malloc(buflen + 1);
686 xlog(L_ERROR, "Failed to insert: no memory");
689 memset(buf, 0, buflen + 1);
691 fd = open(path, O_RDONLY);
693 xlog(L_ERROR, "Failed to insert: "
694 "could not open original file %s: %m", path);
698 len = read(fd, buf, (size_t)stb.st_size);
699 if (exact_error_check(len, (size_t)stb.st_size)) {
700 xlog(L_ERROR, "Failed to insert: "
701 "could not read original file %s: %m", path);
709 if (nsm_atomic_write(path, buf, buflen))
718 * nsm_insert_monitored_host - write callback data for one host to disk
719 * @hostname: C string containing a hostname
720 * @sap: sockaddr containing NLM callback address
721 * @mon: SM_MON arguments to save
723 * Returns true if successful, otherwise false if some error occurs.
726 nsm_insert_monitored_host(const char *hostname, const struct sockaddr *sap,
729 static char buf[LINELEN + 1 + SM_MAXSTRLEN + 2];
731 _Bool result = false;
736 path = nsm_make_record_pathname(NSM_MONITOR_DIR, hostname);
738 xlog(L_ERROR, "Failed to insert: bad monitor hostname '%s'",
743 size = nsm_create_monitor_record(buf, sizeof(buf), sap, m);
745 xlog(L_ERROR, "Failed to insert: record too long");
750 * If exclusive create fails, we're adding a new line to an
753 fd = open(path, O_WRONLY | O_CREAT | O_EXCL | O_SYNC, S_IRUSR | S_IWUSR);
755 if (errno != EEXIST) {
756 xlog(L_ERROR, "Failed to insert: creating %s: %m", path);
760 result = nsm_append_monitored_host(path, buf);
765 len = write(fd, buf, size);
766 if (exact_error_check(len, size)) {
767 xlog_warn("Failed to insert: writing %s: %m", path);
772 if (close(fd) == -1) {
773 xlog(L_ERROR, "Failed to insert: closing %s: %m", path);
783 __attribute_noinline__
785 nsm_parse_line(char *line, struct sockaddr_in *sin, struct mon *m)
791 c = strchr(line, '\n');
795 count = sscanf(line, "%8x %8x %8x %8x ",
796 (unsigned int *)&sin->sin_addr.s_addr,
797 (unsigned int *)&m->mon_id.my_id.my_prog,
798 (unsigned int *)&m->mon_id.my_id.my_vers,
799 (unsigned int *)&m->mon_id.my_id.my_proc);
803 c = line + RPCARGSLEN;
804 for (i = 0; i < SM_PRIV_SIZE; i++) {
805 if (sscanf(c, "%2x", &tmp) != 1)
807 m->priv[i] = (char)tmp;
812 m->mon_id.mon_name = c;
813 while (*c != '\0' && *c != ' ')
819 m->mon_id.my_id.my_name = c;
825 * Stuff a 'struct mon' with callback data, and call @func.
827 * Returns the count of in-core records created.
830 nsm_read_line(const char *hostname, const time_t timestamp, char *line,
833 struct sockaddr_in sin = {
834 .sin_family = AF_INET,
838 if (!nsm_parse_line(line, &sin, &m))
841 return func(hostname, (struct sockaddr *)(char *)&sin, &m, timestamp);
845 * Given a filename, reads data from a file under NSM_MONITOR_DIR
846 * and invokes @func so caller can populate their in-core
847 * database with this data.
850 nsm_load_host(const char *directory, const char *filename, nsm_populate_t func)
852 char buf[LINELEN + 1 + SM_MAXSTRLEN + 2];
853 unsigned int result = 0;
858 path = nsm_make_record_pathname(directory, filename);
862 if (stat(path, &stb) == -1) {
863 xlog(L_ERROR, "Failed to stat %s: %m", path);
867 f = fopen(path, "r");
869 xlog(L_ERROR, "Failed to open %s: %m", path);
873 while (fgets(buf, (int)sizeof(buf), f) != NULL) {
874 buf[sizeof(buf) - 1] = '\0';
875 result += nsm_read_line(filename, stb.st_mtime, buf, func);
878 xlog(L_ERROR, "Failed to read monitor data from %s", path);
889 nsm_load_dir(const char *directory, nsm_populate_t func)
891 unsigned int count = 0;
896 path = nsm_make_pathname(directory);
898 xlog(L_ERROR, "Failed to allocate path for directory %s",
906 xlog(L_ERROR, "Failed to open directory %s: %m",
911 while ((de = readdir(dir)) != NULL) {
912 if (de->d_type != (unsigned char)DT_REG)
914 if (de->d_name[0] == '.')
917 count += nsm_load_host(directory, de->d_name, func);
925 * nsm_load_monitor_list - load list of hosts to monitor
926 * @func: callback function to create entry for one host
928 * Returns the count of hosts that were found in the directory.
931 nsm_load_monitor_list(nsm_populate_t func)
933 return nsm_load_dir(NSM_MONITOR_DIR, func);
937 * nsm_load_notify_list - load list of hosts to notify
938 * @func: callback function to create entry for one host
940 * Returns the count of hosts that were found in the directory.
943 nsm_load_notify_list(nsm_populate_t func)
945 return nsm_load_dir(NSM_NOTIFY_DIR, func);
949 nsm_delete_host(const char *directory, const char *hostname,
950 const char *mon_name, const char *my_name)
952 char line[LINELEN + 1 + SM_MAXSTRLEN + 2];
959 path = nsm_make_record_pathname(directory, hostname);
961 xlog(L_ERROR, "Bad filename, not deleting");
965 if (stat(path, &stb) == -1) {
966 xlog(L_ERROR, "Failed to delete: "
967 "could not stat original file %s: %m", path);
970 remaining = (size_t)stb.st_size + 1;
972 outbuf = malloc(remaining);
973 if (outbuf == NULL) {
974 xlog(L_ERROR, "Failed to delete: no memory");
978 f = fopen(path, "r");
980 xlog(L_ERROR, "Failed to delete: "
981 "could not open original file %s: %m", path);
986 * Walk the records in the file, and copy the non-matching
987 * ones to our output buffer.
990 while (fgets(line, (int)sizeof(line), f) != NULL) {
991 struct sockaddr_in sin;
995 if (!nsm_parse_line(line, &sin, &m)) {
996 xlog(L_ERROR, "Failed to delete: "
997 "could not parse original file %s", path);
1002 if (strcmp(mon_name, m.mon_id.mon_name) == 0 &&
1003 strcmp(my_name, m.mon_id.my_id.my_name) == 0)
1006 /* nsm_parse_line destroys the contents of line[], so
1007 * reconstruct the copy in our output buffer. */
1008 len = nsm_create_monitor_record(next, remaining,
1009 (struct sockaddr *)(char *)&sin, &m);
1011 xlog(L_ERROR, "Failed to delete: "
1012 "could not construct output record");
1023 * If nothing was copied when we're done, then unlink the file.
1024 * Otherwise, atomically update the contents of the file.
1026 if (next != outbuf) {
1027 if (!nsm_atomic_write(path, outbuf, strlen(outbuf)))
1028 xlog(L_ERROR, "Failed to delete: "
1029 "could not write new file %s: %m", path);
1031 if (unlink(path) == -1)
1032 xlog(L_ERROR, "Failed to delete: "
1033 "could not unlink file %s: %m", path);
1042 * nsm_delete_monitored_host - delete on-disk record for monitored host
1043 * @hostname: '\0'-terminated C string containing hostname of record to delete
1044 * @mon_name: '\0'-terminated C string containing monname of record to delete
1045 * @my_name: '\0'-terminated C string containing myname of record to delete
1049 nsm_delete_monitored_host(const char *hostname, const char *mon_name,
1050 const char *my_name)
1052 nsm_delete_host(NSM_MONITOR_DIR, hostname, mon_name, my_name);
1056 * nsm_delete_notified_host - delete on-disk host record after notification
1057 * @hostname: '\0'-terminated C string containing hostname of record to delete
1058 * @mon_name: '\0'-terminated C string containing monname of record to delete
1059 * @my_name: '\0'-terminated C string containing myname of record to delete
1063 nsm_delete_notified_host(const char *hostname, const char *mon_name,
1064 const char *my_name)
1066 nsm_delete_host(NSM_NOTIFY_DIR, hostname, mon_name, my_name);