utils/statd/sm-notify.c

   1 /*
   2  * Send NSM notify calls to all hosts listed in /var/lib/sm
   3  *
   4  * Copyright (C) 2004-2006 Olaf Kirch <okir@suse.de>
   5  */
   6
   7 #include <sys/types.h>
   8 #include <sys/socket.h>
   9 #include <sys/stat.h>
  10 #include <sys/poll.h>
  11 #include <sys/param.h>
  12 #include <sys/syslog.h>
  13 #include <arpa/inet.h>
  14 #include <dirent.h>
  15 #include <time.h>
  16 #include <stdio.h>
  17 #include <getopt.h>
  18 #include <stdlib.h>
  19 #include <fcntl.h>
  20 #include <unistd.h>
  21 #include <string.h>
  22 #include <stdarg.h>
  23 #include <netdb.h>
  24 #include <errno.h>
  25 #include <grp.h>
  26
  27 #ifndef BASEDIR
  28 # ifdef NFS_STATEDIR
  29 #  define BASEDIR               NFS_STATEDIR
  30 # else
  31 #  define BASEDIR               "/var/lib/nfs"
  32 # endif
  33 #endif
  34
  35 #define DEFAULT_SM_STATE_PATH   BASEDIR "/state"
  36 #define DEFAULT_SM_DIR_PATH     BASEDIR "/sm"
  37 #define DEFAULT_SM_BAK_PATH     DEFAULT_SM_DIR_PATH ".bak"
  38
  39 char *_SM_BASE_PATH = BASEDIR;
  40 char *_SM_STATE_PATH = DEFAULT_SM_STATE_PATH;
  41 char *_SM_DIR_PATH = DEFAULT_SM_DIR_PATH;
  42 char *_SM_BAK_PATH = DEFAULT_SM_BAK_PATH;
  43
  44 #define NSM_PROG        100024
  45 #define NSM_PROGRAM     100024
  46 #define NSM_VERSION     1
  47 #define NSM_TIMEOUT     2
  48 #define NSM_NOTIFY      6
  49 #define NSM_MAX_TIMEOUT 120     /* don't make this too big */
  50 #define MAXMSGSIZE      256
  51
  52 typedef struct sockaddr_storage nsm_address;
  53
  54 struct nsm_host {
  55         struct nsm_host *       next;
  56         char *                  name;
  57         char *                  path;
  58         nsm_address             addr;
  59         struct addrinfo         *ai;
  60         time_t                  last_used;
  61         time_t                  send_next;
  62         unsigned int            timeout;
  63         unsigned int            retries;
  64         unsigned int            xid;
  65 };
  66
  67 static char             nsm_hostname[256];
  68 static uint32_t         nsm_state;
  69 static int              opt_debug = 0;
  70 static int              opt_quiet = 0;
  71 static int              opt_update_state = 1;
  72 static unsigned int     opt_max_retry = 15 * 60;
  73 static char *           opt_srcaddr = 0;
  74 static uint16_t         opt_srcport = 0;
  75 static int              log_syslog = 0;
  76
  77 static unsigned int     nsm_get_state(int);
  78 static void             notify(void);
  79 static void             notify_host(int, struct nsm_host *);
  80 static void             recv_reply(int);
  81 static void             backup_hosts(const char *, const char *);
  82 static void             get_hosts(const char *);
  83 static void             insert_host(struct nsm_host *);
  84 struct nsm_host *       find_host(uint32_t);
  85 static int              addr_get_port(nsm_address *);
  86 static void             addr_set_port(nsm_address *, int);
  87 static struct addrinfo  *host_lookup(int, const char *);
  88 void                    nsm_log(int fac, const char *fmt, ...);
  89 static int              record_pid();
  90 static void             drop_privs(void);
  91 static void set_kernel_nsm_state(int state);
  92
  93 static struct nsm_host *        hosts = NULL;
  94
  95 int
  96 main(int argc, char **argv)
  97 {
  98         int     c;
  99         int     force = 0;
 100
 101         while ((c = getopt(argc, argv, "dm:np:v:qP:f")) != -1) {
 102                 switch (c) {
 103                 case 'f':
 104                         force = 1;
 105                         break;
 106                 case 'd':
 107                         opt_debug++;
 108                         break;
 109                 case 'm':
 110                         opt_max_retry = atoi(optarg) * 60;
 111                         break;
 112                 case 'n':
 113                         opt_update_state = 0;
 114                         break;
 115                 case 'p':
 116                         opt_srcport = atoi(optarg);
 117                         break;
 118                 case 'v':
 119                         opt_srcaddr = optarg;
 120                         break;
 121                 case 'q':
 122                         opt_quiet = 1;
 123                         break;
 124                 case 'P':
 125                         _SM_BASE_PATH = strdup(optarg);
 126                         _SM_STATE_PATH = malloc(strlen(optarg)+1+sizeof("state"));
 127                         _SM_DIR_PATH = malloc(strlen(optarg)+1+sizeof("sm"));
 128                         _SM_BAK_PATH = malloc(strlen(optarg)+1+sizeof("sm.bak"));
 129                         if (_SM_BASE_PATH == NULL ||
 130                             _SM_STATE_PATH == NULL ||
 131                             _SM_DIR_PATH == NULL ||
 132                             _SM_BAK_PATH == NULL) {
 133                                 nsm_log(LOG_WARNING, "unable to allocate memory");
 134                                 exit(1);
 135                         }
 136                         strcat(strcpy(_SM_STATE_PATH, _SM_BASE_PATH), "/state");
 137                         strcat(strcpy(_SM_DIR_PATH, _SM_BASE_PATH), "/sm");
 138                         strcat(strcpy(_SM_BAK_PATH, _SM_BASE_PATH), "/sm.bak");
 139                         break;
 140
 141                 default:
 142                         goto usage;
 143                 }
 144         }
 145
 146         if (optind < argc) {
 147 usage:          fprintf(stderr,
 148                         "Usage: sm-notify [-dfq] [-m max-retry-minutes] [-p srcport]\n"
 149                         "            [-P /path/to/state/directory] [-v my_host_name]\n");
 150                 return 1;
 151         }
 152
 153         if (strcmp(_SM_BASE_PATH, BASEDIR) == 0) {
 154                 if (record_pid() == 0 && force == 0 && opt_update_state == 1)
 155                         /* already run, don't try again */
 156                         exit(0);
 157         }
 158
 159         if (opt_srcaddr) {
 160                 strncpy(nsm_hostname, opt_srcaddr, sizeof(nsm_hostname)-1);
 161         } else
 162         if (gethostname(nsm_hostname, sizeof(nsm_hostname)) < 0) {
 163                 perror("gethostname");
 164                 return 1;
 165         }
 166
 167         backup_hosts(_SM_DIR_PATH, _SM_BAK_PATH);
 168         get_hosts(_SM_BAK_PATH);
 169
 170         /* Get and update the NSM state. This will call sync() */
 171         nsm_state = nsm_get_state(opt_update_state);
 172         set_kernel_nsm_state(nsm_state);
 173
 174         if (!opt_debug) {
 175                 if (!opt_quiet)
 176                         printf("Backgrounding to notify hosts...\n");
 177
 178                 openlog("sm-notify", LOG_PID, LOG_DAEMON);
 179                 log_syslog = 1;
 180
 181                 if (daemon(0, 0) < 0) {
 182                         nsm_log(LOG_WARNING, "unable to background: %s",
 183                                         strerror(errno));
 184                         return 1;
 185                 }
 186
 187                 close(0);
 188                 close(1);
 189                 close(2);
 190         }
 191
 192         notify();
 193
 194         if (hosts) {
 195                 struct nsm_host *hp;
 196
 197                 while ((hp = hosts) != 0) {
 198                         hosts = hp->next;
 199                         nsm_log(LOG_NOTICE,
 200                                 "Unable to notify %s, giving up",
 201                                 hp->name);
 202                 }
 203                 return 1;
 204         }
 205
 206         return 0;
 207 }
 208
 209 /*
 210  * Notify hosts
 211  */
 212 void
 213 notify(void)
 214 {
 215         nsm_address local_addr;
 216         time_t  failtime = 0;
 217         int     sock = -1;
 218
 219         sock = socket(AF_INET, SOCK_DGRAM, 0);
 220         if (sock < 0) {
 221                 perror("socket");
 222                 exit(1);
 223         }
 224         fcntl(sock, F_SETFL, O_NONBLOCK);
 225
 226         memset(&local_addr, 0, sizeof(local_addr));
 227         local_addr.ss_family = AF_INET; /* Default to IPv4 */
 228
 229         /* Bind source IP if provided on command line */
 230         if (opt_srcaddr) {
 231                 struct addrinfo *ai = host_lookup(AF_INET, opt_srcaddr);
 232                 if (!ai) {
 233                         nsm_log(LOG_WARNING,
 234                                 "Not a valid hostname or address: \"%s\"\n",
 235                                 opt_srcaddr);
 236                         exit(1);
 237                 }
 238                 memcpy(&local_addr, ai->ai_addr, ai->ai_addrlen);
 239                 /* We know it's IPv4 at this point */
 240         }
 241
 242         /* Use source port if provided on the command line,
 243          * otherwise use bindresvport */
 244         if (opt_srcport) {
 245                 addr_set_port(&local_addr, opt_srcport);
 246                 if (bind(sock, (struct sockaddr *) &local_addr, sizeof(local_addr)) < 0) {
 247                         perror("bind");
 248                         exit(1);
 249                 }
 250         } else {
 251                 (void) bindresvport(sock, (struct sockaddr_in *) &local_addr);
 252         }
 253
 254         if (opt_max_retry)
 255                 failtime = time(NULL) + opt_max_retry;
 256
 257         drop_privs();
 258
 259         while (hosts) {
 260                 struct pollfd   pfd;
 261                 time_t          now = time(NULL);
 262                 unsigned int    sent = 0;
 263                 struct nsm_host *hp;
 264                 long            wait;
 265
 266                 if (failtime && now >= failtime)
 267                         break;
 268
 269                 while ((wait = hosts->send_next - now) <= 0) {
 270                         /* Never send more than 10 packets at once */
 271                         if (sent++ >= 10)
 272                                 break;
 273
 274                         /* Remove queue head */
 275                         hp = hosts;
 276                         hosts = hp->next;
 277
 278                         notify_host(sock, hp);
 279
 280                         /* Set the timeout for this call, using an
 281                            exponential timeout strategy */
 282                         wait = hp->timeout;
 283                         if ((hp->timeout <<= 1) > NSM_MAX_TIMEOUT)
 284                                 hp->timeout = NSM_MAX_TIMEOUT;
 285                         hp->send_next = now + wait;
 286                         hp->retries++;
 287
 288                         insert_host(hp);
 289                 }
 290
 291                 nsm_log(LOG_DEBUG, "Host %s due in %ld seconds",
 292                                 hosts->name, wait);
 293
 294                 pfd.fd = sock;
 295                 pfd.events = POLLIN;
 296
 297                 wait *= 1000;
 298                 if (wait < 100)
 299                         wait = 100;
 300                 if (poll(&pfd, 1, wait) != 1)
 301                         continue;
 302
 303                 recv_reply(sock);
 304         }
 305 }
 306
 307 /*
 308  * Send notification to a single host
 309  */
 310 void
 311 notify_host(int sock, struct nsm_host *host)
 312 {
 313         static unsigned int     xid = 0;
 314         nsm_address             dest;
 315         uint32_t                msgbuf[MAXMSGSIZE], *p;
 316         unsigned int            len;
 317
 318         if (!xid)
 319                 xid = getpid() + time(NULL);
 320         if (!host->xid)
 321                 host->xid = xid++;
 322
 323         memset(msgbuf, 0, sizeof(msgbuf));
 324         p = msgbuf;
 325         *p++ = htonl(host->xid);
 326         *p++ = 0;
 327         *p++ = htonl(2);
 328
 329         /* If we retransmitted 4 times, reset the port to force
 330          * a new portmap lookup (in case statd was restarted).
 331          * We also rotate through multiple IP addresses at this
 332          * point.
 333          */
 334         if (host->retries >= 4) {
 335                 struct addrinfo *hold = host->ai;
 336                 struct addrinfo **next = &host->ai;
 337                 *next = hold->ai_next;
 338                 while ( *next )
 339                         next = & (*next)->ai_next;
 340                 *next = hold;
 341                 hold->ai_next = NULL;
 342                 memcpy(&host->addr, hold->ai_addr, hold->ai_addrlen);
 343                 addr_set_port(&host->addr, 0);
 344                 host->retries = 0;
 345         }
 346
 347         dest = host->addr;
 348         if (addr_get_port(&dest) == 0) {
 349                 /* Build a PMAP packet */
 350                 nsm_log(LOG_DEBUG, "Sending portmap query to %s", host->name);
 351
 352                 addr_set_port(&dest, 111);
 353                 *p++ = htonl(100000);
 354                 *p++ = htonl(2);
 355                 *p++ = htonl(3);
 356
 357                 /* Auth and verf */
 358                 *p++ = 0; *p++ = 0;
 359                 *p++ = 0; *p++ = 0;
 360
 361                 *p++ = htonl(NSM_PROGRAM);
 362                 *p++ = htonl(NSM_VERSION);
 363                 *p++ = htonl(IPPROTO_UDP);
 364                 *p++ = 0;
 365         } else {
 366                 /* Build an SM_NOTIFY packet */
 367                 nsm_log(LOG_DEBUG, "Sending SM_NOTIFY to %s", host->name);
 368
 369                 *p++ = htonl(NSM_PROGRAM);
 370                 *p++ = htonl(NSM_VERSION);
 371                 *p++ = htonl(NSM_NOTIFY);
 372
 373                 /* Auth and verf */
 374                 *p++ = 0; *p++ = 0;
 375                 *p++ = 0; *p++ = 0;
 376
 377                 /* state change */
 378                 len = strlen(nsm_hostname);
 379                 *p++ = htonl(len);
 380                 memcpy(p, nsm_hostname, len);
 381                 p += (len + 3) >> 2;
 382                 *p++ = htonl(nsm_state);
 383         }
 384         len = (p - msgbuf) << 2;
 385
 386         sendto(sock, msgbuf, len, 0, (struct sockaddr *) &dest, sizeof(dest));
 387 }
 388
 389 /*
 390  * Receive reply from remote host
 391  */
 392 void
 393 recv_reply(int sock)
 394 {
 395         struct nsm_host *hp;
 396         uint32_t        msgbuf[MAXMSGSIZE], *p, *end;
 397         uint32_t        xid;
 398         int             res;
 399
 400         res = recv(sock, msgbuf, sizeof(msgbuf), 0);
 401         if (res < 0)
 402                 return;
 403
 404         nsm_log(LOG_DEBUG, "Received packet...");
 405
 406         p = msgbuf;
 407         end = p + (res >> 2);
 408
 409         xid = ntohl(*p++);
 410         if (*p++ != htonl(1)    /* must be REPLY */
 411          || *p++ != htonl(0)    /* must be ACCEPTED */
 412          || *p++ != htonl(0)    /* must be NULL verifier */
 413          || *p++ != htonl(0)
 414          || *p++ != htonl(0))   /* must be SUCCESS */
 415                 return;
 416
 417         /* Before we look at the data, find the host struct for
 418            this reply */
 419         if ((hp = find_host(xid)) == NULL)
 420                 return;
 421
 422         if (addr_get_port(&hp->addr) == 0) {
 423                 /* This was a portmap request */
 424                 unsigned int    port;
 425
 426                 port = ntohl(*p++);
 427                 if (p > end)
 428                         goto fail;
 429
 430                 hp->send_next = time(NULL);
 431                 if (port == 0) {
 432                         /* No binding for statd. Delay the next
 433                          * portmap query for max timeout */
 434                         nsm_log(LOG_DEBUG, "No statd on %s", hp->name);
 435                         hp->timeout = NSM_MAX_TIMEOUT;
 436                         hp->send_next += NSM_MAX_TIMEOUT;
 437                 } else {
 438                         addr_set_port(&hp->addr, port);
 439                         if (hp->timeout >= NSM_MAX_TIMEOUT / 4)
 440                                 hp->timeout = NSM_MAX_TIMEOUT / 4;
 441                 }
 442                 hp->xid = 0;
 443         } else {
 444                 /* Successful NOTIFY call. Server returns void,
 445                  * so nothing we need to do here (except
 446                  * check that we didn't read past the end of the
 447                  * packet)
 448                  */
 449                 if (p <= end) {
 450                         nsm_log(LOG_DEBUG, "Host %s notified successfully", hp->name);
 451                         unlink(hp->path);
 452                         free(hp->name);
 453                         free(hp->path);
 454                         free(hp);
 455                         freeaddrinfo(hp->ai);
 456                         return;
 457                 }
 458         }
 459
 460 fail:   /* Re-insert the host */
 461         insert_host(hp);
 462 }
 463
 464 /*
 465  * Back up all hosts from the sm directory to sm.bak
 466  */
 467 static void
 468 backup_hosts(const char *dirname, const char *bakname)
 469 {
 470         struct dirent   *de;
 471         DIR             *dir;
 472
 473         if (!(dir = opendir(dirname))) {
 474                 perror(dirname);
 475                 return;
 476         }
 477
 478         while ((de = readdir(dir)) != NULL) {
 479                 char    src[1024], dst[1024];
 480
 481                 if (de->d_name[0] == '.')
 482                         continue;
 483
 484                 snprintf(src, sizeof(src), "%s/%s", dirname, de->d_name);
 485                 snprintf(dst, sizeof(dst), "%s/%s", bakname, de->d_name);
 486                 if (rename(src, dst) < 0) {
 487                         nsm_log(LOG_WARNING,
 488                                 "Failed to rename %s -> %s: %m",
 489                                 src, dst);
 490                 }
 491         }
 492         closedir(dir);
 493 }
 494
 495 /*
 496  * Get all entries from sm.bak and convert them to host names
 497  */
 498 static void
 499 get_hosts(const char *dirname)
 500 {
 501         struct nsm_host *host;
 502         struct dirent   *de;
 503         DIR             *dir;
 504
 505         if (!(dir = opendir(dirname))) {
 506                 perror(dirname);
 507                 return;
 508         }
 509
 510         host = NULL;
 511         while ((de = readdir(dir)) != NULL) {
 512                 struct stat     stb;
 513                 char            path[1024];
 514
 515                 if (de->d_name[0] == '.')
 516                         continue;
 517                 if (host == NULL)
 518                         host = calloc(1, sizeof(*host));
 519
 520                 snprintf(path, sizeof(path), "%s/%s", dirname, de->d_name);
 521                 if (stat(path, &stb) < 0)
 522                         continue;
 523
 524                 host->ai = host_lookup(AF_UNSPEC, de->d_name);
 525                 if (! host->ai) {
 526                         nsm_log(LOG_WARNING,
 527                                 "%s doesn't seem to be a valid address, skipped",
 528                                 de->d_name);
 529                         unlink(path);
 530                         continue;
 531                 }
 532
 533                 host->last_used = stb.st_mtime;
 534                 host->timeout = NSM_TIMEOUT;
 535                 host->path = strdup(path);
 536                 host->name = strdup(de->d_name);
 537                 host->retries = 100; /* force address retry */
 538
 539                 insert_host(host);
 540                 host = NULL;
 541         }
 542         closedir(dir);
 543
 544         if (host)
 545                 free(host);
 546 }
 547
 548 /*
 549  * Insert host into sorted list
 550  */
 551 void
 552 insert_host(struct nsm_host *host)
 553 {
 554         struct nsm_host **where, *p;
 555
 556         where = &hosts;
 557         while ((p = *where) != 0) {
 558                 /* Sort in ascending order of timeout */
 559                 if (host->send_next < p->send_next)
 560                         break;
 561                 /* If we have the same timeout, put the
 562                  * most recently used host first.
 563                  * This makes sure that "recent" hosts
 564                  * get notified first.
 565                  */
 566                 if (host->send_next == p->send_next
 567                  && host->last_used > p->last_used)
 568                         break;
 569                 where = &p->next;
 570         }
 571
 572         host->next = *where;
 573         *where = host;
 574 }
 575
 576 /*
 577  * Find host given the XID
 578  */
 579 struct nsm_host *
 580 find_host(uint32_t xid)
 581 {
 582         struct nsm_host **where, *p;
 583
 584         where = &hosts;
 585         while ((p = *where) != 0) {
 586                 if (p->xid == xid) {
 587                         *where = p->next;
 588                         return p;
 589                 }
 590                 where = &p->next;
 591         }
 592         return NULL;
 593 }
 594
 595
 596 /*
 597  * Retrieve the current NSM state
 598  */
 599 unsigned int
 600 nsm_get_state(int update)
 601 {
 602         char            newfile[PATH_MAX];
 603         int             fd, state;
 604
 605         if ((fd = open(_SM_STATE_PATH, O_RDONLY)) < 0) {
 606                 if (!opt_quiet) {
 607                         nsm_log(LOG_WARNING, "%s: %m", _SM_STATE_PATH);
 608                         nsm_log(LOG_WARNING, "Creating %s, set initial state 1",
 609                                 _SM_STATE_PATH);
 610                 }
 611                 state = 1;
 612                 update = 1;
 613         } else {
 614                 if (read(fd, &state, sizeof(state)) != sizeof(state)) {
 615                         nsm_log(LOG_WARNING,
 616                                 "%s: bad file size, setting state = 1",
 617                                 _SM_STATE_PATH);
 618                         state = 1;
 619                         update = 1;
 620                 } else {
 621                         if (!(state & 1))
 622                                 state += 1;
 623                 }
 624                 close(fd);
 625         }
 626
 627         if (update) {
 628                 state += 2;
 629                 snprintf(newfile, sizeof(newfile),
 630                                 "%s.new", _SM_STATE_PATH);
 631                 if ((fd = open(newfile, O_CREAT|O_WRONLY, 0644)) < 0) {
 632                         nsm_log(LOG_WARNING, "Cannot create %s: %m", newfile);
 633                         exit(1);
 634                 }
 635                 if (write(fd, &state, sizeof(state)) != sizeof(state)) {
 636                         nsm_log(LOG_WARNING,
 637                                 "Failed to write state to %s", newfile);
 638                         exit(1);
 639                 }
 640                 close(fd);
 641                 if (rename(newfile, _SM_STATE_PATH) < 0) {
 642                         nsm_log(LOG_WARNING,
 643                                 "Cannot create %s: %m", _SM_STATE_PATH);
 644                         exit(1);
 645                 }
 646                 sync();
 647         }
 648
 649         return state;
 650 }
 651
 652 /*
 653  * Address handling utilities
 654  */
 655
 656 int
 657 addr_get_port(nsm_address *addr)
 658 {
 659         switch (((struct sockaddr *) addr)->sa_family) {
 660         case AF_INET:
 661                 return ntohs(((struct sockaddr_in *) addr)->sin_port);
 662         case AF_INET6:
 663                 return ntohs(((struct sockaddr_in6 *) addr)->sin6_port);
 664         }
 665         return 0;
 666 }
 667
 668 static void
 669 addr_set_port(nsm_address *addr, int port)
 670 {
 671         switch (((struct sockaddr *) addr)->sa_family) {
 672         case AF_INET:
 673                 ((struct sockaddr_in *) addr)->sin_port = htons(port);
 674                 break;
 675         case AF_INET6:
 676                 ((struct sockaddr_in6 *) addr)->sin6_port = htons(port);
 677         }
 678 }
 679
 680 static struct addrinfo *
 681 host_lookup(int af, const char *name)
 682 {
 683         struct addrinfo hints, *ai;
 684
 685         memset(&hints, 0, sizeof(hints));
 686         hints.ai_family = af;
 687         hints.ai_protocol = IPPROTO_UDP;
 688
 689         if (getaddrinfo(name, NULL, &hints, &ai) != 0)
 690                 return NULL;
 691
 692         return ai;
 693 }
 694
 695 /*
 696  * Log a message
 697  */
 698 void
 699 nsm_log(int fac, const char *fmt, ...)
 700 {
 701         va_list ap;
 702
 703         if (fac == LOG_DEBUG && !opt_debug)
 704                 return;
 705
 706         va_start(ap, fmt);
 707         if (log_syslog)
 708                 vsyslog(fac, fmt, ap);
 709         else {
 710                 vfprintf(stderr, fmt, ap);
 711                 fputs("\n", stderr);
 712         }
 713         va_end(ap);
 714 }
 715
 716 /*
 717  * Record pid in /var/run/sm-notify.pid
 718  * This file should remain until a reboot, even if the
 719  * program exits.
 720  * If file already exists, fail.
 721  */
 722 static int record_pid()
 723 {
 724         char pid[20];
 725         int fd;
 726
 727         snprintf(pid, 20, "%d\n", getpid());
 728         fd = open("/var/run/sm-notify.pid", O_CREAT|O_EXCL|O_WRONLY, 0600);
 729         if (fd < 0)
 730                 return 0;
 731         write(fd, pid, strlen(pid));
 732         close(fd);
 733         return 1;
 734 }
 735
 736 /* Drop privileges to match owner of state-directory
 737  * (in case a reply triggers some unknown bug).
 738  */
 739 static void drop_privs(void)
 740 {
 741         struct stat st;
 742
 743         if (stat(_SM_DIR_PATH, &st) == -1 &&
 744             stat(_SM_BASE_PATH, &st) == -1) {
 745                 st.st_uid = 0;
 746                 st.st_gid = 0;
 747         }
 748
 749         if (st.st_uid == 0) {
 750                 nsm_log(LOG_WARNING,
 751                         "sm-notify running as root. chown %s to choose different user\n",
 752                     _SM_DIR_PATH);
 753                 return;
 754         }
 755
 756         setgroups(0, NULL);
 757         if (setgid(st.st_gid) == -1
 758             || setuid(st.st_uid) == -1) {
 759                 nsm_log(LOG_ERR, "Fail to drop privileges");
 760                 exit(1);
 761         }
 762 }
 763
 764 static void set_kernel_nsm_state(int state)
 765 {
 766         int fd;
 767
 768         fd = open("/proc/sys/fs/nfs/nsm_local_state",O_WRONLY);
 769         if (fd >= 0) {
 770                 char buf[20];
 771                 snprintf(buf, sizeof(buf), "%d", state);
 772                 write(fd, buf, strlen(buf));
 773                 close(fd);
 774         }
 775 }