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