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 #ifdef HAVE_CONFIG_H
   8 #include <config.h>
   9 #endif
  10
  11 #include <sys/types.h>
  12 #include <sys/socket.h>
  13 #include <sys/stat.h>
  14 #include <sys/poll.h>
  15 #include <sys/param.h>
  16 #include <sys/syslog.h>
  17 #include <arpa/inet.h>
  18 #include <dirent.h>
  19 #include <time.h>
  20 #include <stdio.h>
  21 #include <getopt.h>
  22 #include <stdlib.h>
  23 #include <fcntl.h>
  24 #include <unistd.h>
  25 #include <string.h>
  26 #include <stdarg.h>
  27 #include <netdb.h>
  28 #include <errno.h>
  29 #include <grp.h>
  30
  31 #ifndef BASEDIR
  32 # ifdef NFS_STATEDIR
  33 #  define BASEDIR               NFS_STATEDIR
  34 # else
  35 #  define BASEDIR               "/var/lib/nfs"
  36 # endif
  37 #endif
  38
  39 #define DEFAULT_SM_STATE_PATH   BASEDIR "/state"
  40 #define DEFAULT_SM_DIR_PATH     BASEDIR "/sm"
  41 #define DEFAULT_SM_BAK_PATH     DEFAULT_SM_DIR_PATH ".bak"
  42
  43 char *_SM_BASE_PATH = BASEDIR;
  44 char *_SM_STATE_PATH = DEFAULT_SM_STATE_PATH;
  45 char *_SM_DIR_PATH = DEFAULT_SM_DIR_PATH;
  46 char *_SM_BAK_PATH = DEFAULT_SM_BAK_PATH;
  47
  48 #define NSM_PROG        100024
  49 #define NSM_PROGRAM     100024
  50 #define NSM_VERSION     1
  51 #define NSM_TIMEOUT     2
  52 #define NSM_NOTIFY      6
  53 #define NSM_MAX_TIMEOUT 120     /* don't make this too big */
  54 #define MAXMSGSIZE      256
  55
  56 struct nsm_host {
  57         struct nsm_host *       next;
  58         char *                  name;
  59         char *                  path;
  60         struct sockaddr_storage addr;
  61         struct addrinfo         *ai;
  62         time_t                  last_used;
  63         time_t                  send_next;
  64         unsigned int            timeout;
  65         unsigned int            retries;
  66         unsigned int            xid;
  67 };
  68
  69 static char             nsm_hostname[256];
  70 static uint32_t         nsm_state;
  71 static int              opt_debug = 0;
  72 static int              opt_quiet = 0;
  73 static int              opt_update_state = 1;
  74 static unsigned int     opt_max_retry = 15 * 60;
  75 static char *           opt_srcaddr = 0;
  76 static uint16_t         opt_srcport = 0;
  77 static int              log_syslog = 0;
  78
  79 static unsigned int     nsm_get_state(int);
  80 static void             notify(void);
  81 static int              notify_host(int, struct nsm_host *);
  82 static void             recv_reply(int);
  83 static void             backup_hosts(const char *, const char *);
  84 static void             get_hosts(const char *);
  85 static void             insert_host(struct nsm_host *);
  86 static struct nsm_host *find_host(uint32_t);
  87 static void             nsm_log(int fac, const char *fmt, ...);
  88 static int              record_pid(void);
  89 static void             drop_privs(void);
  90 static void             set_kernel_nsm_state(int state);
  91
  92 static struct nsm_host *        hosts = NULL;
  93
  94 /*
  95  * Address handling utilities
  96  */
  97
  98 static unsigned short smn_get_port(const struct sockaddr *sap)
  99 {
 100         switch (sap->sa_family) {
 101         case AF_INET:
 102                 return ntohs(((struct sockaddr_in *)sap)->sin_port);
 103         case AF_INET6:
 104                 return ntohs(((struct sockaddr_in6 *)sap)->sin6_port);
 105         }
 106         return 0;
 107 }
 108
 109 static void smn_set_port(struct sockaddr *sap, const unsigned short port)
 110 {
 111         switch (sap->sa_family) {
 112         case AF_INET:
 113                 ((struct sockaddr_in *)sap)->sin_port = htons(port);
 114                 break;
 115         case AF_INET6:
 116                 ((struct sockaddr_in6 *)sap)->sin6_port = htons(port);
 117                 break;
 118         }
 119 }
 120
 121 static struct addrinfo *smn_lookup(const sa_family_t family, const char *name)
 122 {
 123         struct addrinfo *ai, hint = {
 124                 .ai_family      = family,
 125                 .ai_protocol    = IPPROTO_UDP,
 126         };
 127
 128         if (getaddrinfo(name, NULL, &hint, &ai) != 0)
 129                 return NULL;
 130
 131         return ai;
 132 }
 133
 134 static void smn_forget_host(struct nsm_host *host)
 135 {
 136         unlink(host->path);
 137         free(host->path);
 138         free(host->name);
 139         if (host->ai)
 140                 freeaddrinfo(host->ai);
 141
 142         free(host);
 143 }
 144
 145 int
 146 main(int argc, char **argv)
 147 {
 148         int     c;
 149         int     force = 0;
 150
 151         while ((c = getopt(argc, argv, "dm:np:v:qP:f")) != -1) {
 152                 switch (c) {
 153                 case 'f':
 154                         force = 1;
 155                         break;
 156                 case 'd':
 157                         opt_debug++;
 158                         break;
 159                 case 'm':
 160                         opt_max_retry = atoi(optarg) * 60;
 161                         break;
 162                 case 'n':
 163                         opt_update_state = 0;
 164                         break;
 165                 case 'p':
 166                         opt_srcport = atoi(optarg);
 167                         break;
 168                 case 'v':
 169                         opt_srcaddr = optarg;
 170                         break;
 171                 case 'q':
 172                         opt_quiet = 1;
 173                         break;
 174                 case 'P':
 175                         _SM_BASE_PATH = strdup(optarg);
 176                         _SM_STATE_PATH = malloc(strlen(optarg)+1+sizeof("state"));
 177                         _SM_DIR_PATH = malloc(strlen(optarg)+1+sizeof("sm"));
 178                         _SM_BAK_PATH = malloc(strlen(optarg)+1+sizeof("sm.bak"));
 179                         if (_SM_BASE_PATH == NULL ||
 180                             _SM_STATE_PATH == NULL ||
 181                             _SM_DIR_PATH == NULL ||
 182                             _SM_BAK_PATH == NULL) {
 183                                 nsm_log(LOG_ERR, "unable to allocate memory");
 184                                 exit(1);
 185                         }
 186                         strcat(strcpy(_SM_STATE_PATH, _SM_BASE_PATH), "/state");
 187                         strcat(strcpy(_SM_DIR_PATH, _SM_BASE_PATH), "/sm");
 188                         strcat(strcpy(_SM_BAK_PATH, _SM_BASE_PATH), "/sm.bak");
 189                         break;
 190
 191                 default:
 192                         goto usage;
 193                 }
 194         }
 195
 196         if (optind < argc) {
 197 usage:          fprintf(stderr,
 198                         "Usage: sm-notify [-dfq] [-m max-retry-minutes] [-p srcport]\n"
 199                         "            [-P /path/to/state/directory] [-v my_host_name]\n");
 200                 exit(1);
 201         }
 202
 203         log_syslog = 1;
 204         openlog("sm-notify", LOG_PID, LOG_DAEMON);
 205
 206         if (strcmp(_SM_BASE_PATH, BASEDIR) == 0) {
 207                 if (record_pid() == 0 && force == 0 && opt_update_state == 1) {
 208                         /* already run, don't try again */
 209                         nsm_log(LOG_NOTICE, "Already notifying clients; Exiting!");
 210                         exit(0);
 211                 }
 212         }
 213
 214         if (opt_srcaddr) {
 215                 strncpy(nsm_hostname, opt_srcaddr, sizeof(nsm_hostname)-1);
 216         } else
 217         if (gethostname(nsm_hostname, sizeof(nsm_hostname)) < 0) {
 218                 nsm_log(LOG_ERR, "Failed to obtain name of local host: %s",
 219                         strerror(errno));
 220                 exit(1);
 221         }
 222
 223         backup_hosts(_SM_DIR_PATH, _SM_BAK_PATH);
 224         get_hosts(_SM_BAK_PATH);
 225
 226         /* If there are not hosts to notify, just exit */
 227         if (!hosts) {
 228                 nsm_log(LOG_DEBUG, "No hosts to notify; exiting");
 229                 return 0;
 230         }
 231
 232         /* Get and update the NSM state. This will call sync() */
 233         nsm_state = nsm_get_state(opt_update_state);
 234         set_kernel_nsm_state(nsm_state);
 235
 236         if (!opt_debug) {
 237                 if (!opt_quiet)
 238                         printf("Backgrounding to notify hosts...\n");
 239
 240                 if (daemon(0, 0) < 0) {
 241                         nsm_log(LOG_ERR, "unable to background: %s",
 242                                         strerror(errno));
 243                         exit(1);
 244                 }
 245
 246                 close(0);
 247                 close(1);
 248                 close(2);
 249         }
 250
 251         notify();
 252
 253         if (hosts) {
 254                 struct nsm_host *hp;
 255
 256                 while ((hp = hosts) != 0) {
 257                         hosts = hp->next;
 258                         nsm_log(LOG_NOTICE,
 259                                 "Unable to notify %s, giving up",
 260                                 hp->name);
 261                 }
 262                 exit(1);
 263         }
 264
 265         exit(0);
 266 }
 267
 268 /*
 269  * Notify hosts
 270  */
 271 static void
 272 notify(void)
 273 {
 274         struct sockaddr_storage address;
 275         struct sockaddr *local_addr = (struct sockaddr *)&address;
 276         time_t  failtime = 0;
 277         int     sock = -1;
 278         int retry_cnt = 0;
 279
 280  retry:
 281         sock = socket(AF_INET, SOCK_DGRAM, 0);
 282         if (sock < 0) {
 283                 nsm_log(LOG_ERR, "Failed to create RPC socket: %s",
 284                         strerror(errno));
 285                 exit(1);
 286         }
 287         fcntl(sock, F_SETFL, O_NONBLOCK);
 288
 289         memset(&address, 0, sizeof(address));
 290         local_addr->sa_family = AF_INET;        /* Default to IPv4 */
 291
 292         /* Bind source IP if provided on command line */
 293         if (opt_srcaddr) {
 294                 struct addrinfo *ai = smn_lookup(AF_INET, opt_srcaddr);
 295                 if (!ai) {
 296                         nsm_log(LOG_ERR,
 297                                 "Not a valid hostname or address: \"%s\"",
 298                                 opt_srcaddr);
 299                         exit(1);
 300                 }
 301
 302                 /* We know it's IPv4 at this point */
 303                 memcpy(local_addr, ai->ai_addr, ai->ai_addrlen);
 304
 305                 freeaddrinfo(ai);
 306         }
 307
 308         /* Use source port if provided on the command line,
 309          * otherwise use bindresvport */
 310         if (opt_srcport) {
 311                 smn_set_port(local_addr, opt_srcport);
 312                 if (bind(sock, local_addr, sizeof(struct sockaddr_in)) < 0) {
 313                         nsm_log(LOG_ERR, "Failed to bind RPC socket: %s",
 314                                 strerror(errno));
 315                         exit(1);
 316                 }
 317         } else {
 318                 struct servent *se;
 319                 struct sockaddr_in *sin = (struct sockaddr_in *)local_addr;
 320                 (void) bindresvport(sock, sin);
 321                 /* try to avoid known ports */
 322                 se = getservbyport(sin->sin_port, "udp");
 323                 if (se && retry_cnt < 100) {
 324                         retry_cnt++;
 325                         close(sock);
 326                         goto retry;
 327                 }
 328         }
 329
 330         if (opt_max_retry)
 331                 failtime = time(NULL) + opt_max_retry;
 332
 333         drop_privs();
 334
 335         while (hosts) {
 336                 struct pollfd   pfd;
 337                 time_t          now = time(NULL);
 338                 unsigned int    sent = 0;
 339                 struct nsm_host *hp;
 340                 long            wait;
 341
 342                 if (failtime && now >= failtime)
 343                         break;
 344
 345                 while (hosts && ((wait = hosts->send_next - now) <= 0)) {
 346                         /* Never send more than 10 packets at once */
 347                         if (sent++ >= 10)
 348                                 break;
 349
 350                         /* Remove queue head */
 351                         hp = hosts;
 352                         hosts = hp->next;
 353
 354                         if (notify_host(sock, hp))
 355                                 continue;
 356
 357                         /* Set the timeout for this call, using an
 358                            exponential timeout strategy */
 359                         wait = hp->timeout;
 360                         if ((hp->timeout <<= 1) > NSM_MAX_TIMEOUT)
 361                                 hp->timeout = NSM_MAX_TIMEOUT;
 362                         hp->send_next = now + wait;
 363                         hp->retries++;
 364
 365                         insert_host(hp);
 366                 }
 367                 if (hosts == NULL)
 368                         return;
 369
 370                 nsm_log(LOG_DEBUG, "Host %s due in %ld seconds",
 371                                 hosts->name, wait);
 372
 373                 pfd.fd = sock;
 374                 pfd.events = POLLIN;
 375
 376                 wait *= 1000;
 377                 if (wait < 100)
 378                         wait = 100;
 379                 if (poll(&pfd, 1, wait) != 1)
 380                         continue;
 381
 382                 recv_reply(sock);
 383         }
 384 }
 385
 386 /*
 387  * Send notification to a single host
 388  */
 389 static int
 390 notify_host(int sock, struct nsm_host *host)
 391 {
 392         struct sockaddr_storage address;
 393         struct sockaddr *dest = (struct sockaddr *)&address;
 394         socklen_t destlen = sizeof(address);
 395         static unsigned int     xid = 0;
 396         uint32_t                msgbuf[MAXMSGSIZE], *p;
 397         unsigned int            len;
 398
 399         if (!xid)
 400                 xid = getpid() + time(NULL);
 401         if (!host->xid)
 402                 host->xid = xid++;
 403
 404         if (host->ai == NULL) {
 405                 host->ai = smn_lookup(AF_UNSPEC, host->name);
 406                 if (host->ai == NULL) {
 407                         nsm_log(LOG_WARNING,
 408                                 "%s doesn't seem to be a valid address,"
 409                                 " skipped", host->name);
 410                         smn_forget_host(host);
 411                         return 1;
 412                 }
 413         }
 414
 415         memset(msgbuf, 0, sizeof(msgbuf));
 416         p = msgbuf;
 417         *p++ = htonl(host->xid);
 418         *p++ = 0;
 419         *p++ = htonl(2);
 420
 421         /* If we retransmitted 4 times, reset the port to force
 422          * a new portmap lookup (in case statd was restarted).
 423          * We also rotate through multiple IP addresses at this
 424          * point.
 425          */
 426         if (host->retries >= 4) {
 427                 struct addrinfo *first = host->ai;
 428                 struct addrinfo **next = &host->ai;
 429
 430                 /* remove the first entry from the list */
 431                 host->ai = first->ai_next;
 432                 first->ai_next = NULL;
 433                 /* find the end of the list */
 434                 next = &first->ai_next;
 435                 while ( *next )
 436                         next = & (*next)->ai_next;
 437                 /* put first entry at end */
 438                 *next = first;
 439                 memcpy(&host->addr, first->ai_addr, first->ai_addrlen);
 440                 smn_set_port((struct sockaddr *)&host->addr, 0);
 441                 host->retries = 0;
 442         }
 443
 444         memcpy(dest, &host->addr, destlen);
 445         if (smn_get_port(dest) == 0) {
 446                 /* Build a PMAP packet */
 447                 nsm_log(LOG_DEBUG, "Sending portmap query to %s", host->name);
 448
 449                 smn_set_port(dest, 111);
 450                 *p++ = htonl(100000);
 451                 *p++ = htonl(2);
 452                 *p++ = htonl(3);
 453
 454                 /* Auth and verf */
 455                 *p++ = 0; *p++ = 0;
 456                 *p++ = 0; *p++ = 0;
 457
 458                 *p++ = htonl(NSM_PROGRAM);
 459                 *p++ = htonl(NSM_VERSION);
 460                 *p++ = htonl(IPPROTO_UDP);
 461                 *p++ = 0;
 462         } else {
 463                 /* Build an SM_NOTIFY packet */
 464                 nsm_log(LOG_DEBUG, "Sending SM_NOTIFY to %s", host->name);
 465
 466                 *p++ = htonl(NSM_PROGRAM);
 467                 *p++ = htonl(NSM_VERSION);
 468                 *p++ = htonl(NSM_NOTIFY);
 469
 470                 /* Auth and verf */
 471                 *p++ = 0; *p++ = 0;
 472                 *p++ = 0; *p++ = 0;
 473
 474                 /* state change */
 475                 len = strlen(nsm_hostname);
 476                 *p++ = htonl(len);
 477                 memcpy(p, nsm_hostname, len);
 478                 p += (len + 3) >> 2;
 479                 *p++ = htonl(nsm_state);
 480         }
 481         len = (p - msgbuf) << 2;
 482
 483         if (sendto(sock, msgbuf, len, 0, dest, destlen) < 0)
 484                 nsm_log(LOG_WARNING, "Sending Reboot Notification to "
 485                         "'%s' failed: errno %d (%s)", host->name, errno, strerror(errno));
 486
 487         return 0;
 488 }
 489
 490 /*
 491  * Receive reply from remote host
 492  */
 493 static void
 494 recv_reply(int sock)
 495 {
 496         struct nsm_host *hp;
 497         struct sockaddr *sap;
 498         uint32_t        msgbuf[MAXMSGSIZE], *p, *end;
 499         uint32_t        xid;
 500         int             res;
 501
 502         res = recv(sock, msgbuf, sizeof(msgbuf), 0);
 503         if (res < 0)
 504                 return;
 505
 506         nsm_log(LOG_DEBUG, "Received packet...");
 507
 508         p = msgbuf;
 509         end = p + (res >> 2);
 510
 511         xid = ntohl(*p++);
 512         if (*p++ != htonl(1)    /* must be REPLY */
 513          || *p++ != htonl(0)    /* must be ACCEPTED */
 514          || *p++ != htonl(0)    /* must be NULL verifier */
 515          || *p++ != htonl(0)
 516          || *p++ != htonl(0))   /* must be SUCCESS */
 517                 return;
 518
 519         /* Before we look at the data, find the host struct for
 520            this reply */
 521         if ((hp = find_host(xid)) == NULL)
 522                 return;
 523         sap = (struct sockaddr *)&hp->addr;
 524
 525         if (smn_get_port(sap) == 0) {
 526                 /* This was a portmap request */
 527                 unsigned int    port;
 528
 529                 port = ntohl(*p++);
 530                 if (p > end)
 531                         goto fail;
 532
 533                 hp->send_next = time(NULL);
 534                 if (port == 0) {
 535                         /* No binding for statd. Delay the next
 536                          * portmap query for max timeout */
 537                         nsm_log(LOG_DEBUG, "No statd on %s", hp->name);
 538                         hp->timeout = NSM_MAX_TIMEOUT;
 539                         hp->send_next += NSM_MAX_TIMEOUT;
 540                 } else {
 541                         smn_set_port(sap, port);
 542                         if (hp->timeout >= NSM_MAX_TIMEOUT / 4)
 543                                 hp->timeout = NSM_MAX_TIMEOUT / 4;
 544                 }
 545                 hp->xid = 0;
 546         } else {
 547                 /* Successful NOTIFY call. Server returns void,
 548                  * so nothing we need to do here (except
 549                  * check that we didn't read past the end of the
 550                  * packet)
 551                  */
 552                 if (p <= end) {
 553                         nsm_log(LOG_DEBUG, "Host %s notified successfully",
 554                                         hp->name);
 555                         smn_forget_host(hp);
 556                         return;
 557                 }
 558         }
 559
 560 fail:   /* Re-insert the host */
 561         insert_host(hp);
 562 }
 563
 564 /*
 565  * Back up all hosts from the sm directory to sm.bak
 566  */
 567 static void
 568 backup_hosts(const char *dirname, const char *bakname)
 569 {
 570         struct dirent   *de;
 571         DIR             *dir;
 572
 573         if (!(dir = opendir(dirname))) {
 574                 nsm_log(LOG_WARNING,
 575                         "Failed to open %s: %s", dirname, strerror(errno));
 576                 return;
 577         }
 578
 579         while ((de = readdir(dir)) != NULL) {
 580                 char    src[1024], dst[1024];
 581
 582                 if (de->d_name[0] == '.')
 583                         continue;
 584
 585                 snprintf(src, sizeof(src), "%s/%s", dirname, de->d_name);
 586                 snprintf(dst, sizeof(dst), "%s/%s", bakname, de->d_name);
 587                 if (rename(src, dst) < 0) {
 588                         nsm_log(LOG_WARNING,
 589                                 "Failed to rename %s -> %s: %m",
 590                                 src, dst);
 591                 }
 592         }
 593         closedir(dir);
 594 }
 595
 596 /*
 597  * Get all entries from sm.bak and convert them to host entries
 598  */
 599 static void
 600 get_hosts(const char *dirname)
 601 {
 602         struct nsm_host *host;
 603         struct dirent   *de;
 604         DIR             *dir;
 605
 606         if (!(dir = opendir(dirname))) {
 607                 nsm_log(LOG_WARNING,
 608                         "Failed to open %s: %s", dirname, strerror(errno));
 609                 return;
 610         }
 611
 612         host = NULL;
 613         while ((de = readdir(dir)) != NULL) {
 614                 struct stat     stb;
 615                 char            path[1024];
 616
 617                 if (de->d_name[0] == '.')
 618                         continue;
 619                 if (host == NULL)
 620                         host = calloc(1, sizeof(*host));
 621                 if (host == NULL) {
 622                         nsm_log(LOG_WARNING, "Unable to allocate memory");
 623                         return;
 624                 }
 625
 626                 snprintf(path, sizeof(path), "%s/%s", dirname, de->d_name);
 627                 if (stat(path, &stb) < 0)
 628                         continue;
 629
 630                 host->last_used = stb.st_mtime;
 631                 host->timeout = NSM_TIMEOUT;
 632                 host->path = strdup(path);
 633                 host->name = strdup(de->d_name);
 634                 host->retries = 100; /* force address retry */
 635
 636                 insert_host(host);
 637                 host = NULL;
 638         }
 639         closedir(dir);
 640
 641         if (host)
 642                 free(host);
 643 }
 644
 645 /*
 646  * Insert host into sorted list
 647  */
 648 static void
 649 insert_host(struct nsm_host *host)
 650 {
 651         struct nsm_host **where, *p;
 652
 653         where = &hosts;
 654         while ((p = *where) != 0) {
 655                 /* Sort in ascending order of timeout */
 656                 if (host->send_next < p->send_next)
 657                         break;
 658                 /* If we have the same timeout, put the
 659                  * most recently used host first.
 660                  * This makes sure that "recent" hosts
 661                  * get notified first.
 662                  */
 663                 if (host->send_next == p->send_next
 664                  && host->last_used > p->last_used)
 665                         break;
 666                 where = &p->next;
 667         }
 668
 669         host->next = *where;
 670         *where = host;
 671 }
 672
 673 /*
 674  * Find host given the XID
 675  */
 676 static struct nsm_host *
 677 find_host(uint32_t xid)
 678 {
 679         struct nsm_host **where, *p;
 680
 681         where = &hosts;
 682         while ((p = *where) != 0) {
 683                 if (p->xid == xid) {
 684                         *where = p->next;
 685                         return p;
 686                 }
 687                 where = &p->next;
 688         }
 689         return NULL;
 690 }
 691
 692
 693 /*
 694  * Retrieve the current NSM state
 695  */
 696 static unsigned int
 697 nsm_get_state(int update)
 698 {
 699         char            newfile[PATH_MAX];
 700         int             fd, state;
 701
 702         if ((fd = open(_SM_STATE_PATH, O_RDONLY)) < 0) {
 703                 if (!opt_quiet) {
 704                         nsm_log(LOG_WARNING, "%s: %m", _SM_STATE_PATH);
 705                         nsm_log(LOG_WARNING, "Creating %s, set initial state 1",
 706                                 _SM_STATE_PATH);
 707                 }
 708                 state = 1;
 709                 update = 1;
 710         } else {
 711                 if (read(fd, &state, sizeof(state)) != sizeof(state)) {
 712                         nsm_log(LOG_WARNING,
 713                                 "%s: bad file size, setting state = 1",
 714                                 _SM_STATE_PATH);
 715                         state = 1;
 716                         update = 1;
 717                 } else {
 718                         if (!(state & 1))
 719                                 state += 1;
 720                 }
 721                 close(fd);
 722         }
 723
 724         if (update) {
 725                 state += 2;
 726                 snprintf(newfile, sizeof(newfile),
 727                                 "%s.new", _SM_STATE_PATH);
 728                 if ((fd = open(newfile, O_CREAT|O_WRONLY, 0644)) < 0) {
 729                         nsm_log(LOG_ERR, "Cannot create %s: %m", newfile);
 730                         exit(1);
 731                 }
 732                 if (write(fd, &state, sizeof(state)) != sizeof(state)) {
 733                         nsm_log(LOG_ERR,
 734                                 "Failed to write state to %s", newfile);
 735                         exit(1);
 736                 }
 737                 close(fd);
 738                 if (rename(newfile, _SM_STATE_PATH) < 0) {
 739                         nsm_log(LOG_ERR,
 740                                 "Cannot create %s: %m", _SM_STATE_PATH);
 741                         exit(1);
 742                 }
 743                 sync();
 744         }
 745
 746         return state;
 747 }
 748
 749 /*
 750  * Log a message
 751  */
 752 static void
 753 nsm_log(int fac, const char *fmt, ...)
 754 {
 755         va_list ap;
 756
 757         if (fac == LOG_DEBUG && !opt_debug)
 758                 return;
 759
 760         va_start(ap, fmt);
 761         if (log_syslog)
 762                 vsyslog(fac, fmt, ap);
 763         else {
 764                 vfprintf(stderr, fmt, ap);
 765                 fputs("\n", stderr);
 766         }
 767         va_end(ap);
 768 }
 769
 770 /*
 771  * Record pid in /var/run/sm-notify.pid
 772  * This file should remain until a reboot, even if the
 773  * program exits.
 774  * If file already exists, fail.
 775  */
 776 static int record_pid(void)
 777 {
 778         char pid[20];
 779         int fd;
 780
 781         snprintf(pid, 20, "%d\n", getpid());
 782         fd = open("/var/run/sm-notify.pid", O_CREAT|O_EXCL|O_WRONLY, 0600);
 783         if (fd < 0)
 784                 return 0;
 785         write(fd, pid, strlen(pid));
 786         close(fd);
 787         return 1;
 788 }
 789
 790 /* Drop privileges to match owner of state-directory
 791  * (in case a reply triggers some unknown bug).
 792  */
 793 static void drop_privs(void)
 794 {
 795         struct stat st;
 796
 797         if (stat(_SM_DIR_PATH, &st) == -1 &&
 798             stat(_SM_BASE_PATH, &st) == -1) {
 799                 st.st_uid = 0;
 800                 st.st_gid = 0;
 801         }
 802
 803         if (st.st_uid == 0) {
 804                 nsm_log(LOG_WARNING,
 805                         "sm-notify running as root. chown %s to choose different user",
 806                     _SM_DIR_PATH);
 807                 return;
 808         }
 809
 810         setgroups(0, NULL);
 811         if (setgid(st.st_gid) == -1
 812             || setuid(st.st_uid) == -1) {
 813                 nsm_log(LOG_ERR, "Fail to drop privileges");
 814                 exit(1);
 815         }
 816 }
 817
 818 static void set_kernel_nsm_state(int state)
 819 {
 820         int fd;
 821
 822         fd = open("/proc/sys/fs/nfs/nsm_local_state",O_WRONLY);
 823         if (fd >= 0) {
 824                 char buf[20];
 825                 snprintf(buf, sizeof(buf), "%d", state);
 826                 write(fd, buf, strlen(buf));
 827                 close(fd);
 828         }
 829 }