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(void);
  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         int retry_cnt = 0;
 219
 220  retry:
 221         sock = socket(AF_INET, SOCK_DGRAM, 0);
 222         if (sock < 0) {
 223                 perror("socket");
 224                 exit(1);
 225         }
 226         fcntl(sock, F_SETFL, O_NONBLOCK);
 227
 228         memset(&local_addr, 0, sizeof(local_addr));
 229         local_addr.ss_family = AF_INET; /* Default to IPv4 */
 230
 231         /* Bind source IP if provided on command line */
 232         if (opt_srcaddr) {
 233                 struct addrinfo *ai = host_lookup(AF_INET, opt_srcaddr);
 234                 if (!ai) {
 235                         nsm_log(LOG_WARNING,
 236                                 "Not a valid hostname or address: \"%s\"\n",
 237                                 opt_srcaddr);
 238                         exit(1);
 239                 }
 240                 memcpy(&local_addr, ai->ai_addr, ai->ai_addrlen);
 241                 /* We know it's IPv4 at this point */
 242         }
 243
 244         /* Use source port if provided on the command line,
 245          * otherwise use bindresvport */
 246         if (opt_srcport) {
 247                 addr_set_port(&local_addr, opt_srcport);
 248                 if (bind(sock, (struct sockaddr *) &local_addr, sizeof(local_addr)) < 0) {
 249                         perror("bind");
 250                         exit(1);
 251                 }
 252         } else {
 253                 struct servent *se;
 254                 struct sockaddr_in *sin = (struct sockaddr_in *)&local_addr;
 255                 (void) bindresvport(sock, sin);
 256                 /* try to avoid known ports */
 257                 se = getservbyport(sin->sin_port, "udp");
 258                 if (se && retry_cnt < 100) {
 259                         retry_cnt++;
 260                         close(sock);
 261                         goto retry;
 262                 }
 263         }
 264
 265         if (opt_max_retry)
 266                 failtime = time(NULL) + opt_max_retry;
 267
 268         drop_privs();
 269
 270         while (hosts) {
 271                 struct pollfd   pfd;
 272                 time_t          now = time(NULL);
 273                 unsigned int    sent = 0;
 274                 struct nsm_host *hp;
 275                 long            wait;
 276
 277                 if (failtime && now >= failtime)
 278                         break;
 279
 280                 while ((wait = hosts->send_next - now) <= 0) {
 281                         /* Never send more than 10 packets at once */
 282                         if (sent++ >= 10)
 283                                 break;
 284
 285                         /* Remove queue head */
 286                         hp = hosts;
 287                         hosts = hp->next;
 288
 289                         notify_host(sock, hp);
 290
 291                         /* Set the timeout for this call, using an
 292                            exponential timeout strategy */
 293                         wait = hp->timeout;
 294                         if ((hp->timeout <<= 1) > NSM_MAX_TIMEOUT)
 295                                 hp->timeout = NSM_MAX_TIMEOUT;
 296                         hp->send_next = now + wait;
 297                         hp->retries++;
 298
 299                         insert_host(hp);
 300                 }
 301
 302                 nsm_log(LOG_DEBUG, "Host %s due in %ld seconds",
 303                                 hosts->name, wait);
 304
 305                 pfd.fd = sock;
 306                 pfd.events = POLLIN;
 307
 308                 wait *= 1000;
 309                 if (wait < 100)
 310                         wait = 100;
 311                 if (poll(&pfd, 1, wait) != 1)
 312                         continue;
 313
 314                 recv_reply(sock);
 315         }
 316 }
 317
 318 /*
 319  * Send notification to a single host
 320  */
 321 void
 322 notify_host(int sock, struct nsm_host *host)
 323 {
 324         static unsigned int     xid = 0;
 325         nsm_address             dest;
 326         uint32_t                msgbuf[MAXMSGSIZE], *p;
 327         unsigned int            len;
 328
 329         if (!xid)
 330                 xid = getpid() + time(NULL);
 331         if (!host->xid)
 332                 host->xid = xid++;
 333
 334         memset(msgbuf, 0, sizeof(msgbuf));
 335         p = msgbuf;
 336         *p++ = htonl(host->xid);
 337         *p++ = 0;
 338         *p++ = htonl(2);
 339
 340         /* If we retransmitted 4 times, reset the port to force
 341          * a new portmap lookup (in case statd was restarted).
 342          * We also rotate through multiple IP addresses at this
 343          * point.
 344          */
 345         if (host->retries >= 4) {
 346                 struct addrinfo *hold = host->ai;
 347                 struct addrinfo **next = &host->ai;
 348                 *next = hold->ai_next;
 349                 while ( *next )
 350                         next = & (*next)->ai_next;
 351                 *next = hold;
 352                 hold->ai_next = NULL;
 353                 memcpy(&host->addr, hold->ai_addr, hold->ai_addrlen);
 354                 addr_set_port(&host->addr, 0);
 355                 host->retries = 0;
 356         }
 357
 358         dest = host->addr;
 359         if (addr_get_port(&dest) == 0) {
 360                 /* Build a PMAP packet */
 361                 nsm_log(LOG_DEBUG, "Sending portmap query to %s", host->name);
 362
 363                 addr_set_port(&dest, 111);
 364                 *p++ = htonl(100000);
 365                 *p++ = htonl(2);
 366                 *p++ = htonl(3);
 367
 368                 /* Auth and verf */
 369                 *p++ = 0; *p++ = 0;
 370                 *p++ = 0; *p++ = 0;
 371
 372                 *p++ = htonl(NSM_PROGRAM);
 373                 *p++ = htonl(NSM_VERSION);
 374                 *p++ = htonl(IPPROTO_UDP);
 375                 *p++ = 0;
 376         } else {
 377                 /* Build an SM_NOTIFY packet */
 378                 nsm_log(LOG_DEBUG, "Sending SM_NOTIFY to %s", host->name);
 379
 380                 *p++ = htonl(NSM_PROGRAM);
 381                 *p++ = htonl(NSM_VERSION);
 382                 *p++ = htonl(NSM_NOTIFY);
 383
 384                 /* Auth and verf */
 385                 *p++ = 0; *p++ = 0;
 386                 *p++ = 0; *p++ = 0;
 387
 388                 /* state change */
 389                 len = strlen(nsm_hostname);
 390                 *p++ = htonl(len);
 391                 memcpy(p, nsm_hostname, len);
 392                 p += (len + 3) >> 2;
 393                 *p++ = htonl(nsm_state);
 394         }
 395         len = (p - msgbuf) << 2;
 396
 397         sendto(sock, msgbuf, len, 0, (struct sockaddr *) &dest, sizeof(dest));
 398 }
 399
 400 /*
 401  * Receive reply from remote host
 402  */
 403 void
 404 recv_reply(int sock)
 405 {
 406         struct nsm_host *hp;
 407         uint32_t        msgbuf[MAXMSGSIZE], *p, *end;
 408         uint32_t        xid;
 409         int             res;
 410
 411         res = recv(sock, msgbuf, sizeof(msgbuf), 0);
 412         if (res < 0)
 413                 return;
 414
 415         nsm_log(LOG_DEBUG, "Received packet...");
 416
 417         p = msgbuf;
 418         end = p + (res >> 2);
 419
 420         xid = ntohl(*p++);
 421         if (*p++ != htonl(1)    /* must be REPLY */
 422          || *p++ != htonl(0)    /* must be ACCEPTED */
 423          || *p++ != htonl(0)    /* must be NULL verifier */
 424          || *p++ != htonl(0)
 425          || *p++ != htonl(0))   /* must be SUCCESS */
 426                 return;
 427
 428         /* Before we look at the data, find the host struct for
 429            this reply */
 430         if ((hp = find_host(xid)) == NULL)
 431                 return;
 432
 433         if (addr_get_port(&hp->addr) == 0) {
 434                 /* This was a portmap request */
 435                 unsigned int    port;
 436
 437                 port = ntohl(*p++);
 438                 if (p > end)
 439                         goto fail;
 440
 441                 hp->send_next = time(NULL);
 442                 if (port == 0) {
 443                         /* No binding for statd. Delay the next
 444                          * portmap query for max timeout */
 445                         nsm_log(LOG_DEBUG, "No statd on %s", hp->name);
 446                         hp->timeout = NSM_MAX_TIMEOUT;
 447                         hp->send_next += NSM_MAX_TIMEOUT;
 448                 } else {
 449                         addr_set_port(&hp->addr, port);
 450                         if (hp->timeout >= NSM_MAX_TIMEOUT / 4)
 451                                 hp->timeout = NSM_MAX_TIMEOUT / 4;
 452                 }
 453                 hp->xid = 0;
 454         } else {
 455                 /* Successful NOTIFY call. Server returns void,
 456                  * so nothing we need to do here (except
 457                  * check that we didn't read past the end of the
 458                  * packet)
 459                  */
 460                 if (p <= end) {
 461                         nsm_log(LOG_DEBUG, "Host %s notified successfully", hp->name);
 462                         unlink(hp->path);
 463                         free(hp->name);
 464                         free(hp->path);
 465                         free(hp);
 466                         freeaddrinfo(hp->ai);
 467                         return;
 468                 }
 469         }
 470
 471 fail:   /* Re-insert the host */
 472         insert_host(hp);
 473 }
 474
 475 /*
 476  * Back up all hosts from the sm directory to sm.bak
 477  */
 478 static void
 479 backup_hosts(const char *dirname, const char *bakname)
 480 {
 481         struct dirent   *de;
 482         DIR             *dir;
 483
 484         if (!(dir = opendir(dirname))) {
 485                 perror(dirname);
 486                 return;
 487         }
 488
 489         while ((de = readdir(dir)) != NULL) {
 490                 char    src[1024], dst[1024];
 491
 492                 if (de->d_name[0] == '.')
 493                         continue;
 494
 495                 snprintf(src, sizeof(src), "%s/%s", dirname, de->d_name);
 496                 snprintf(dst, sizeof(dst), "%s/%s", bakname, de->d_name);
 497                 if (rename(src, dst) < 0) {
 498                         nsm_log(LOG_WARNING,
 499                                 "Failed to rename %s -> %s: %m",
 500                                 src, dst);
 501                 }
 502         }
 503         closedir(dir);
 504 }
 505
 506 /*
 507  * Get all entries from sm.bak and convert them to host names
 508  */
 509 static void
 510 get_hosts(const char *dirname)
 511 {
 512         struct nsm_host *host;
 513         struct dirent   *de;
 514         DIR             *dir;
 515
 516         if (!(dir = opendir(dirname))) {
 517                 perror(dirname);
 518                 return;
 519         }
 520
 521         host = NULL;
 522         while ((de = readdir(dir)) != NULL) {
 523                 struct stat     stb;
 524                 char            path[1024];
 525
 526                 if (de->d_name[0] == '.')
 527                         continue;
 528                 if (host == NULL)
 529                         host = calloc(1, sizeof(*host));
 530
 531                 snprintf(path, sizeof(path), "%s/%s", dirname, de->d_name);
 532                 if (stat(path, &stb) < 0)
 533                         continue;
 534
 535                 host->ai = host_lookup(AF_UNSPEC, de->d_name);
 536                 if (! host->ai) {
 537                         nsm_log(LOG_WARNING,
 538                                 "%s doesn't seem to be a valid address, skipped",
 539                                 de->d_name);
 540                         unlink(path);
 541                         continue;
 542                 }
 543
 544                 host->last_used = stb.st_mtime;
 545                 host->timeout = NSM_TIMEOUT;
 546                 host->path = strdup(path);
 547                 host->name = strdup(de->d_name);
 548                 host->retries = 100; /* force address retry */
 549
 550                 insert_host(host);
 551                 host = NULL;
 552         }
 553         closedir(dir);
 554
 555         if (host)
 556                 free(host);
 557 }
 558
 559 /*
 560  * Insert host into sorted list
 561  */
 562 void
 563 insert_host(struct nsm_host *host)
 564 {
 565         struct nsm_host **where, *p;
 566
 567         where = &hosts;
 568         while ((p = *where) != 0) {
 569                 /* Sort in ascending order of timeout */
 570                 if (host->send_next < p->send_next)
 571                         break;
 572                 /* If we have the same timeout, put the
 573                  * most recently used host first.
 574                  * This makes sure that "recent" hosts
 575                  * get notified first.
 576                  */
 577                 if (host->send_next == p->send_next
 578                  && host->last_used > p->last_used)
 579                         break;
 580                 where = &p->next;
 581         }
 582
 583         host->next = *where;
 584         *where = host;
 585 }
 586
 587 /*
 588  * Find host given the XID
 589  */
 590 struct nsm_host *
 591 find_host(uint32_t xid)
 592 {
 593         struct nsm_host **where, *p;
 594
 595         where = &hosts;
 596         while ((p = *where) != 0) {
 597                 if (p->xid == xid) {
 598                         *where = p->next;
 599                         return p;
 600                 }
 601                 where = &p->next;
 602         }
 603         return NULL;
 604 }
 605
 606
 607 /*
 608  * Retrieve the current NSM state
 609  */
 610 unsigned int
 611 nsm_get_state(int update)
 612 {
 613         char            newfile[PATH_MAX];
 614         int             fd, state;
 615
 616         if ((fd = open(_SM_STATE_PATH, O_RDONLY)) < 0) {
 617                 if (!opt_quiet) {
 618                         nsm_log(LOG_WARNING, "%s: %m", _SM_STATE_PATH);
 619                         nsm_log(LOG_WARNING, "Creating %s, set initial state 1",
 620                                 _SM_STATE_PATH);
 621                 }
 622                 state = 1;
 623                 update = 1;
 624         } else {
 625                 if (read(fd, &state, sizeof(state)) != sizeof(state)) {
 626                         nsm_log(LOG_WARNING,
 627                                 "%s: bad file size, setting state = 1",
 628                                 _SM_STATE_PATH);
 629                         state = 1;
 630                         update = 1;
 631                 } else {
 632                         if (!(state & 1))
 633                                 state += 1;
 634                 }
 635                 close(fd);
 636         }
 637
 638         if (update) {
 639                 state += 2;
 640                 snprintf(newfile, sizeof(newfile),
 641                                 "%s.new", _SM_STATE_PATH);
 642                 if ((fd = open(newfile, O_CREAT|O_WRONLY, 0644)) < 0) {
 643                         nsm_log(LOG_WARNING, "Cannot create %s: %m", newfile);
 644                         exit(1);
 645                 }
 646                 if (write(fd, &state, sizeof(state)) != sizeof(state)) {
 647                         nsm_log(LOG_WARNING,
 648                                 "Failed to write state to %s", newfile);
 649                         exit(1);
 650                 }
 651                 close(fd);
 652                 if (rename(newfile, _SM_STATE_PATH) < 0) {
 653                         nsm_log(LOG_WARNING,
 654                                 "Cannot create %s: %m", _SM_STATE_PATH);
 655                         exit(1);
 656                 }
 657                 sync();
 658         }
 659
 660         return state;
 661 }
 662
 663 /*
 664  * Address handling utilities
 665  */
 666
 667 int
 668 addr_get_port(nsm_address *addr)
 669 {
 670         switch (((struct sockaddr *) addr)->sa_family) {
 671         case AF_INET:
 672                 return ntohs(((struct sockaddr_in *) addr)->sin_port);
 673         case AF_INET6:
 674                 return ntohs(((struct sockaddr_in6 *) addr)->sin6_port);
 675         }
 676         return 0;
 677 }
 678
 679 static void
 680 addr_set_port(nsm_address *addr, int port)
 681 {
 682         switch (((struct sockaddr *) addr)->sa_family) {
 683         case AF_INET:
 684                 ((struct sockaddr_in *) addr)->sin_port = htons(port);
 685                 break;
 686         case AF_INET6:
 687                 ((struct sockaddr_in6 *) addr)->sin6_port = htons(port);
 688         }
 689 }
 690
 691 static struct addrinfo *
 692 host_lookup(int af, const char *name)
 693 {
 694         struct addrinfo hints, *ai;
 695
 696         memset(&hints, 0, sizeof(hints));
 697         hints.ai_family = af;
 698         hints.ai_protocol = IPPROTO_UDP;
 699
 700         if (getaddrinfo(name, NULL, &hints, &ai) != 0)
 701                 return NULL;
 702
 703         return ai;
 704 }
 705
 706 /*
 707  * Log a message
 708  */
 709 void
 710 nsm_log(int fac, const char *fmt, ...)
 711 {
 712         va_list ap;
 713
 714         if (fac == LOG_DEBUG && !opt_debug)
 715                 return;
 716
 717         va_start(ap, fmt);
 718         if (log_syslog)
 719                 vsyslog(fac, fmt, ap);
 720         else {
 721                 vfprintf(stderr, fmt, ap);
 722                 fputs("\n", stderr);
 723         }
 724         va_end(ap);
 725 }
 726
 727 /*
 728  * Record pid in /var/run/sm-notify.pid
 729  * This file should remain until a reboot, even if the
 730  * program exits.
 731  * If file already exists, fail.
 732  */
 733 static int record_pid(void)
 734 {
 735         char pid[20];
 736         int fd;
 737
 738         snprintf(pid, 20, "%d\n", getpid());
 739         fd = open("/var/run/sm-notify.pid", O_CREAT|O_EXCL|O_WRONLY, 0600);
 740         if (fd < 0)
 741                 return 0;
 742         write(fd, pid, strlen(pid));
 743         close(fd);
 744         return 1;
 745 }
 746
 747 /* Drop privileges to match owner of state-directory
 748  * (in case a reply triggers some unknown bug).
 749  */
 750 static void drop_privs(void)
 751 {
 752         struct stat st;
 753
 754         if (stat(_SM_DIR_PATH, &st) == -1 &&
 755             stat(_SM_BASE_PATH, &st) == -1) {
 756                 st.st_uid = 0;
 757                 st.st_gid = 0;
 758         }
 759
 760         if (st.st_uid == 0) {
 761                 nsm_log(LOG_WARNING,
 762                         "sm-notify running as root. chown %s to choose different user\n",
 763                     _SM_DIR_PATH);
 764                 return;
 765         }
 766
 767         setgroups(0, NULL);
 768         if (setgid(st.st_gid) == -1
 769             || setuid(st.st_uid) == -1) {
 770                 nsm_log(LOG_ERR, "Fail to drop privileges");
 771                 exit(1);
 772         }
 773 }
 774
 775 static void set_kernel_nsm_state(int state)
 776 {
 777         int fd;
 778
 779         fd = open("/proc/sys/fs/nfs/nsm_local_state",O_WRONLY);
 780         if (fd >= 0) {
 781                 char buf[20];
 782                 snprintf(buf, sizeof(buf), "%d", state);
 783                 write(fd, buf, strlen(buf));
 784                 close(fd);
 785         }
 786 }