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 char *name)
 122 {
 123         struct addrinfo *ai, hint = {
 124 #if HAVE_DECL_AI_ADDRCONFIG
 125                 .ai_flags       = AI_ADDRCONFIG,
 126 #endif  /* HAVE_DECL_AI_ADDRCONFIG */
 127                 .ai_family      = AF_INET,
 128                 .ai_protocol    = IPPROTO_UDP,
 129         };
 130         int error;
 131
 132         error = getaddrinfo(name, NULL, &hint, &ai);
 133         switch (error) {
 134         case 0:
 135                 return ai;
 136         case EAI_SYSTEM:
 137                 if (opt_debug)
 138                         nsm_log(LOG_ERR, "getaddrinfo(3): %s",
 139                                         strerror(errno));
 140                 break;
 141         default:
 142                 if (opt_debug)
 143                         nsm_log(LOG_ERR, "getaddrinfo(3): %s",
 144                                         gai_strerror(error));
 145         }
 146
 147         return NULL;
 148 }
 149
 150 static void smn_forget_host(struct nsm_host *host)
 151 {
 152         unlink(host->path);
 153         free(host->path);
 154         free(host->name);
 155         if (host->ai)
 156                 freeaddrinfo(host->ai);
 157
 158         free(host);
 159 }
 160
 161 int
 162 main(int argc, char **argv)
 163 {
 164         int     c;
 165         int     force = 0;
 166
 167         while ((c = getopt(argc, argv, "dm:np:v:qP:f")) != -1) {
 168                 switch (c) {
 169                 case 'f':
 170                         force = 1;
 171                         break;
 172                 case 'd':
 173                         opt_debug++;
 174                         break;
 175                 case 'm':
 176                         opt_max_retry = atoi(optarg) * 60;
 177                         break;
 178                 case 'n':
 179                         opt_update_state = 0;
 180                         break;
 181                 case 'p':
 182                         opt_srcport = atoi(optarg);
 183                         break;
 184                 case 'v':
 185                         opt_srcaddr = optarg;
 186                         break;
 187                 case 'q':
 188                         opt_quiet = 1;
 189                         break;
 190                 case 'P':
 191                         _SM_BASE_PATH = strdup(optarg);
 192                         _SM_STATE_PATH = malloc(strlen(optarg)+1+sizeof("state"));
 193                         _SM_DIR_PATH = malloc(strlen(optarg)+1+sizeof("sm"));
 194                         _SM_BAK_PATH = malloc(strlen(optarg)+1+sizeof("sm.bak"));
 195                         if (_SM_BASE_PATH == NULL ||
 196                             _SM_STATE_PATH == NULL ||
 197                             _SM_DIR_PATH == NULL ||
 198                             _SM_BAK_PATH == NULL) {
 199                                 nsm_log(LOG_ERR, "unable to allocate memory");
 200                                 exit(1);
 201                         }
 202                         strcat(strcpy(_SM_STATE_PATH, _SM_BASE_PATH), "/state");
 203                         strcat(strcpy(_SM_DIR_PATH, _SM_BASE_PATH), "/sm");
 204                         strcat(strcpy(_SM_BAK_PATH, _SM_BASE_PATH), "/sm.bak");
 205                         break;
 206
 207                 default:
 208                         goto usage;
 209                 }
 210         }
 211
 212         if (optind < argc) {
 213 usage:          fprintf(stderr,
 214                         "Usage: sm-notify [-dfq] [-m max-retry-minutes] [-p srcport]\n"
 215                         "            [-P /path/to/state/directory] [-v my_host_name]\n");
 216                 exit(1);
 217         }
 218
 219         log_syslog = 1;
 220         openlog("sm-notify", LOG_PID, LOG_DAEMON);
 221
 222         if (strcmp(_SM_BASE_PATH, BASEDIR) == 0) {
 223                 if (record_pid() == 0 && force == 0 && opt_update_state == 1) {
 224                         /* already run, don't try again */
 225                         nsm_log(LOG_NOTICE, "Already notifying clients; Exiting!");
 226                         exit(0);
 227                 }
 228         }
 229
 230         if (opt_srcaddr) {
 231                 strncpy(nsm_hostname, opt_srcaddr, sizeof(nsm_hostname)-1);
 232         } else
 233         if (gethostname(nsm_hostname, sizeof(nsm_hostname)) < 0) {
 234                 nsm_log(LOG_ERR, "Failed to obtain name of local host: %s",
 235                         strerror(errno));
 236                 exit(1);
 237         }
 238
 239         backup_hosts(_SM_DIR_PATH, _SM_BAK_PATH);
 240         get_hosts(_SM_BAK_PATH);
 241
 242         /* If there are not hosts to notify, just exit */
 243         if (!hosts) {
 244                 nsm_log(LOG_DEBUG, "No hosts to notify; exiting");
 245                 return 0;
 246         }
 247
 248         /* Get and update the NSM state. This will call sync() */
 249         nsm_state = nsm_get_state(opt_update_state);
 250         set_kernel_nsm_state(nsm_state);
 251
 252         if (!opt_debug) {
 253                 if (!opt_quiet)
 254                         printf("Backgrounding to notify hosts...\n");
 255
 256                 if (daemon(0, 0) < 0) {
 257                         nsm_log(LOG_ERR, "unable to background: %s",
 258                                         strerror(errno));
 259                         exit(1);
 260                 }
 261
 262                 close(0);
 263                 close(1);
 264                 close(2);
 265         }
 266
 267         notify();
 268
 269         if (hosts) {
 270                 struct nsm_host *hp;
 271
 272                 while ((hp = hosts) != 0) {
 273                         hosts = hp->next;
 274                         nsm_log(LOG_NOTICE,
 275                                 "Unable to notify %s, giving up",
 276                                 hp->name);
 277                 }
 278                 exit(1);
 279         }
 280
 281         exit(0);
 282 }
 283
 284 /*
 285  * Notify hosts
 286  */
 287 static void
 288 notify(void)
 289 {
 290         struct sockaddr_storage address;
 291         struct sockaddr *local_addr = (struct sockaddr *)&address;
 292         time_t  failtime = 0;
 293         int     sock = -1;
 294         int retry_cnt = 0;
 295
 296  retry:
 297         sock = socket(AF_INET, SOCK_DGRAM, 0);
 298         if (sock < 0) {
 299                 nsm_log(LOG_ERR, "Failed to create RPC socket: %s",
 300                         strerror(errno));
 301                 exit(1);
 302         }
 303         fcntl(sock, F_SETFL, O_NONBLOCK);
 304
 305         memset(&address, 0, sizeof(address));
 306         local_addr->sa_family = AF_INET;        /* Default to IPv4 */
 307
 308         /* Bind source IP if provided on command line */
 309         if (opt_srcaddr) {
 310                 struct addrinfo *ai = smn_lookup(opt_srcaddr);
 311                 if (!ai) {
 312                         nsm_log(LOG_ERR,
 313                                 "Not a valid hostname or address: \"%s\"",
 314                                 opt_srcaddr);
 315                         exit(1);
 316                 }
 317
 318                 /* We know it's IPv4 at this point */
 319                 memcpy(local_addr, ai->ai_addr, ai->ai_addrlen);
 320
 321                 freeaddrinfo(ai);
 322         }
 323
 324         /* Use source port if provided on the command line,
 325          * otherwise use bindresvport */
 326         if (opt_srcport) {
 327                 smn_set_port(local_addr, opt_srcport);
 328                 if (bind(sock, local_addr, sizeof(struct sockaddr_in)) < 0) {
 329                         nsm_log(LOG_ERR, "Failed to bind RPC socket: %s",
 330                                 strerror(errno));
 331                         exit(1);
 332                 }
 333         } else {
 334                 struct servent *se;
 335                 struct sockaddr_in *sin = (struct sockaddr_in *)local_addr;
 336                 (void) bindresvport(sock, sin);
 337                 /* try to avoid known ports */
 338                 se = getservbyport(sin->sin_port, "udp");
 339                 if (se && retry_cnt < 100) {
 340                         retry_cnt++;
 341                         close(sock);
 342                         goto retry;
 343                 }
 344         }
 345
 346         if (opt_max_retry)
 347                 failtime = time(NULL) + opt_max_retry;
 348
 349         drop_privs();
 350
 351         while (hosts) {
 352                 struct pollfd   pfd;
 353                 time_t          now = time(NULL);
 354                 unsigned int    sent = 0;
 355                 struct nsm_host *hp;
 356                 long            wait;
 357
 358                 if (failtime && now >= failtime)
 359                         break;
 360
 361                 while (hosts && ((wait = hosts->send_next - now) <= 0)) {
 362                         /* Never send more than 10 packets at once */
 363                         if (sent++ >= 10)
 364                                 break;
 365
 366                         /* Remove queue head */
 367                         hp = hosts;
 368                         hosts = hp->next;
 369
 370                         if (notify_host(sock, hp))
 371                                 continue;
 372
 373                         /* Set the timeout for this call, using an
 374                            exponential timeout strategy */
 375                         wait = hp->timeout;
 376                         if ((hp->timeout <<= 1) > NSM_MAX_TIMEOUT)
 377                                 hp->timeout = NSM_MAX_TIMEOUT;
 378                         hp->send_next = now + wait;
 379                         hp->retries++;
 380
 381                         insert_host(hp);
 382                 }
 383                 if (hosts == NULL)
 384                         return;
 385
 386                 nsm_log(LOG_DEBUG, "Host %s due in %ld seconds",
 387                                 hosts->name, wait);
 388
 389                 pfd.fd = sock;
 390                 pfd.events = POLLIN;
 391
 392                 wait *= 1000;
 393                 if (wait < 100)
 394                         wait = 100;
 395                 if (poll(&pfd, 1, wait) != 1)
 396                         continue;
 397
 398                 recv_reply(sock);
 399         }
 400 }
 401
 402 /*
 403  * Send notification to a single host
 404  */
 405 static int
 406 notify_host(int sock, struct nsm_host *host)
 407 {
 408         struct sockaddr_storage address;
 409         struct sockaddr *dest = (struct sockaddr *)&address;
 410         socklen_t destlen = sizeof(address);
 411         static unsigned int     xid = 0;
 412         uint32_t                msgbuf[MAXMSGSIZE], *p;
 413         unsigned int            len;
 414
 415         if (!xid)
 416                 xid = getpid() + time(NULL);
 417         if (!host->xid)
 418                 host->xid = xid++;
 419
 420         if (host->ai == NULL) {
 421                 host->ai = smn_lookup(host->name);
 422                 if (host->ai == NULL) {
 423                         nsm_log(LOG_WARNING,
 424                                 "DNS resolution of %s failed; "
 425                                 "retrying later", host->name);
 426                         return 0;
 427                 }
 428         }
 429
 430         memset(msgbuf, 0, sizeof(msgbuf));
 431         p = msgbuf;
 432         *p++ = htonl(host->xid);
 433         *p++ = 0;
 434         *p++ = htonl(2);
 435
 436         /* If we retransmitted 4 times, reset the port to force
 437          * a new portmap lookup (in case statd was restarted).
 438          * We also rotate through multiple IP addresses at this
 439          * point.
 440          */
 441         if (host->retries >= 4) {
 442                 /* don't rotate if there is only one addrinfo */
 443                 if (host->ai->ai_next == NULL)
 444                         memcpy(&host->addr, host->ai->ai_addr,
 445                                                 host->ai->ai_addrlen);
 446                 else {
 447                         struct addrinfo *first = host->ai;
 448                         struct addrinfo **next = &host->ai;
 449
 450                         /* remove the first entry from the list */
 451                         host->ai = first->ai_next;
 452                         first->ai_next = NULL;
 453                         /* find the end of the list */
 454                         next = &first->ai_next;
 455                         while ( *next )
 456                                 next = & (*next)->ai_next;
 457                         /* put first entry at end */
 458                         *next = first;
 459                         memcpy(&host->addr, first->ai_addr,
 460                                                 first->ai_addrlen);
 461                 }
 462
 463                 smn_set_port((struct sockaddr *)&host->addr, 0);
 464                 host->retries = 0;
 465         }
 466
 467         memcpy(dest, &host->addr, destlen);
 468         if (smn_get_port(dest) == 0) {
 469                 /* Build a PMAP packet */
 470                 nsm_log(LOG_DEBUG, "Sending portmap query to %s", host->name);
 471
 472                 smn_set_port(dest, 111);
 473                 *p++ = htonl(100000);
 474                 *p++ = htonl(2);
 475                 *p++ = htonl(3);
 476
 477                 /* Auth and verf */
 478                 *p++ = 0; *p++ = 0;
 479                 *p++ = 0; *p++ = 0;
 480
 481                 *p++ = htonl(NSM_PROGRAM);
 482                 *p++ = htonl(NSM_VERSION);
 483                 *p++ = htonl(IPPROTO_UDP);
 484                 *p++ = 0;
 485         } else {
 486                 /* Build an SM_NOTIFY packet */
 487                 nsm_log(LOG_DEBUG, "Sending SM_NOTIFY to %s", host->name);
 488
 489                 *p++ = htonl(NSM_PROGRAM);
 490                 *p++ = htonl(NSM_VERSION);
 491                 *p++ = htonl(NSM_NOTIFY);
 492
 493                 /* Auth and verf */
 494                 *p++ = 0; *p++ = 0;
 495                 *p++ = 0; *p++ = 0;
 496
 497                 /* state change */
 498                 len = strlen(nsm_hostname);
 499                 *p++ = htonl(len);
 500                 memcpy(p, nsm_hostname, len);
 501                 p += (len + 3) >> 2;
 502                 *p++ = htonl(nsm_state);
 503         }
 504         len = (p - msgbuf) << 2;
 505
 506         if (sendto(sock, msgbuf, len, 0, dest, destlen) < 0)
 507                 nsm_log(LOG_WARNING, "Sending Reboot Notification to "
 508                         "'%s' failed: errno %d (%s)", host->name, errno, strerror(errno));
 509
 510         return 0;
 511 }
 512
 513 /*
 514  * Receive reply from remote host
 515  */
 516 static void
 517 recv_reply(int sock)
 518 {
 519         struct nsm_host *hp;
 520         struct sockaddr *sap;
 521         uint32_t        msgbuf[MAXMSGSIZE], *p, *end;
 522         uint32_t        xid;
 523         int             res;
 524
 525         res = recv(sock, msgbuf, sizeof(msgbuf), 0);
 526         if (res < 0)
 527                 return;
 528
 529         nsm_log(LOG_DEBUG, "Received packet...");
 530
 531         p = msgbuf;
 532         end = p + (res >> 2);
 533
 534         xid = ntohl(*p++);
 535         if (*p++ != htonl(1)    /* must be REPLY */
 536          || *p++ != htonl(0)    /* must be ACCEPTED */
 537          || *p++ != htonl(0)    /* must be NULL verifier */
 538          || *p++ != htonl(0)
 539          || *p++ != htonl(0))   /* must be SUCCESS */
 540                 return;
 541
 542         /* Before we look at the data, find the host struct for
 543            this reply */
 544         if ((hp = find_host(xid)) == NULL)
 545                 return;
 546         sap = (struct sockaddr *)&hp->addr;
 547
 548         if (smn_get_port(sap) == 0) {
 549                 /* This was a portmap request */
 550                 unsigned int    port;
 551
 552                 port = ntohl(*p++);
 553                 if (p > end)
 554                         goto fail;
 555
 556                 hp->send_next = time(NULL);
 557                 if (port == 0) {
 558                         /* No binding for statd. Delay the next
 559                          * portmap query for max timeout */
 560                         nsm_log(LOG_DEBUG, "No statd on %s", hp->name);
 561                         hp->timeout = NSM_MAX_TIMEOUT;
 562                         hp->send_next += NSM_MAX_TIMEOUT;
 563                 } else {
 564                         smn_set_port(sap, port);
 565                         if (hp->timeout >= NSM_MAX_TIMEOUT / 4)
 566                                 hp->timeout = NSM_MAX_TIMEOUT / 4;
 567                 }
 568                 hp->xid = 0;
 569         } else {
 570                 /* Successful NOTIFY call. Server returns void,
 571                  * so nothing we need to do here (except
 572                  * check that we didn't read past the end of the
 573                  * packet)
 574                  */
 575                 if (p <= end) {
 576                         nsm_log(LOG_DEBUG, "Host %s notified successfully",
 577                                         hp->name);
 578                         smn_forget_host(hp);
 579                         return;
 580                 }
 581         }
 582
 583 fail:   /* Re-insert the host */
 584         insert_host(hp);
 585 }
 586
 587 /*
 588  * Back up all hosts from the sm directory to sm.bak
 589  */
 590 static void
 591 backup_hosts(const char *dirname, const char *bakname)
 592 {
 593         struct dirent   *de;
 594         DIR             *dir;
 595
 596         if (!(dir = opendir(dirname))) {
 597                 nsm_log(LOG_WARNING,
 598                         "Failed to open %s: %s", dirname, strerror(errno));
 599                 return;
 600         }
 601
 602         while ((de = readdir(dir)) != NULL) {
 603                 char    src[1024], dst[1024];
 604
 605                 if (de->d_name[0] == '.')
 606                         continue;
 607
 608                 snprintf(src, sizeof(src), "%s/%s", dirname, de->d_name);
 609                 snprintf(dst, sizeof(dst), "%s/%s", bakname, de->d_name);
 610                 if (rename(src, dst) < 0) {
 611                         nsm_log(LOG_WARNING,
 612                                 "Failed to rename %s -> %s: %m",
 613                                 src, dst);
 614                 }
 615         }
 616         closedir(dir);
 617 }
 618
 619 /*
 620  * Get all entries from sm.bak and convert them to host entries
 621  */
 622 static void
 623 get_hosts(const char *dirname)
 624 {
 625         struct nsm_host *host;
 626         struct dirent   *de;
 627         DIR             *dir;
 628
 629         if (!(dir = opendir(dirname))) {
 630                 nsm_log(LOG_WARNING,
 631                         "Failed to open %s: %s", dirname, strerror(errno));
 632                 return;
 633         }
 634
 635         host = NULL;
 636         while ((de = readdir(dir)) != NULL) {
 637                 struct stat     stb;
 638                 char            path[1024];
 639
 640                 if (de->d_name[0] == '.')
 641                         continue;
 642                 if (host == NULL)
 643                         host = calloc(1, sizeof(*host));
 644                 if (host == NULL) {
 645                         nsm_log(LOG_WARNING, "Unable to allocate memory");
 646                         return;
 647                 }
 648
 649                 snprintf(path, sizeof(path), "%s/%s", dirname, de->d_name);
 650                 if (stat(path, &stb) < 0)
 651                         continue;
 652
 653                 host->last_used = stb.st_mtime;
 654                 host->timeout = NSM_TIMEOUT;
 655                 host->path = strdup(path);
 656                 host->name = strdup(de->d_name);
 657                 host->retries = 100; /* force address retry */
 658
 659                 insert_host(host);
 660                 host = NULL;
 661         }
 662         closedir(dir);
 663
 664         if (host)
 665                 free(host);
 666 }
 667
 668 /*
 669  * Insert host into sorted list
 670  */
 671 static void
 672 insert_host(struct nsm_host *host)
 673 {
 674         struct nsm_host **where, *p;
 675
 676         where = &hosts;
 677         while ((p = *where) != 0) {
 678                 /* Sort in ascending order of timeout */
 679                 if (host->send_next < p->send_next)
 680                         break;
 681                 /* If we have the same timeout, put the
 682                  * most recently used host first.
 683                  * This makes sure that "recent" hosts
 684                  * get notified first.
 685                  */
 686                 if (host->send_next == p->send_next
 687                  && host->last_used > p->last_used)
 688                         break;
 689                 where = &p->next;
 690         }
 691
 692         host->next = *where;
 693         *where = host;
 694 }
 695
 696 /*
 697  * Find host given the XID
 698  */
 699 static struct nsm_host *
 700 find_host(uint32_t xid)
 701 {
 702         struct nsm_host **where, *p;
 703
 704         where = &hosts;
 705         while ((p = *where) != 0) {
 706                 if (p->xid == xid) {
 707                         *where = p->next;
 708                         return p;
 709                 }
 710                 where = &p->next;
 711         }
 712         return NULL;
 713 }
 714
 715
 716 /*
 717  * Retrieve the current NSM state
 718  */
 719 static unsigned int
 720 nsm_get_state(int update)
 721 {
 722         char            newfile[PATH_MAX];
 723         int             fd, state;
 724
 725         if ((fd = open(_SM_STATE_PATH, O_RDONLY)) < 0) {
 726                 if (!opt_quiet) {
 727                         nsm_log(LOG_WARNING, "%s: %m", _SM_STATE_PATH);
 728                         nsm_log(LOG_WARNING, "Creating %s, set initial state 1",
 729                                 _SM_STATE_PATH);
 730                 }
 731                 state = 1;
 732                 update = 1;
 733         } else {
 734                 if (read(fd, &state, sizeof(state)) != sizeof(state)) {
 735                         nsm_log(LOG_WARNING,
 736                                 "%s: bad file size, setting state = 1",
 737                                 _SM_STATE_PATH);
 738                         state = 1;
 739                         update = 1;
 740                 } else {
 741                         if (!(state & 1))
 742                                 state += 1;
 743                 }
 744                 close(fd);
 745         }
 746
 747         if (update) {
 748                 state += 2;
 749                 snprintf(newfile, sizeof(newfile),
 750                                 "%s.new", _SM_STATE_PATH);
 751                 if ((fd = open(newfile, O_CREAT|O_WRONLY, 0644)) < 0) {
 752                         nsm_log(LOG_ERR, "Cannot create %s: %m", newfile);
 753                         exit(1);
 754                 }
 755                 if (write(fd, &state, sizeof(state)) != sizeof(state)) {
 756                         nsm_log(LOG_ERR,
 757                                 "Failed to write state to %s", newfile);
 758                         exit(1);
 759                 }
 760                 close(fd);
 761                 if (rename(newfile, _SM_STATE_PATH) < 0) {
 762                         nsm_log(LOG_ERR,
 763                                 "Cannot create %s: %m", _SM_STATE_PATH);
 764                         exit(1);
 765                 }
 766                 sync();
 767         }
 768
 769         return state;
 770 }
 771
 772 /*
 773  * Log a message
 774  */
 775 static void
 776 nsm_log(int fac, const char *fmt, ...)
 777 {
 778         va_list ap;
 779
 780         if (fac == LOG_DEBUG && !opt_debug)
 781                 return;
 782
 783         va_start(ap, fmt);
 784         if (log_syslog)
 785                 vsyslog(fac, fmt, ap);
 786         else {
 787                 vfprintf(stderr, fmt, ap);
 788                 fputs("\n", stderr);
 789         }
 790         va_end(ap);
 791 }
 792
 793 /*
 794  * Record pid in /var/run/sm-notify.pid
 795  * This file should remain until a reboot, even if the
 796  * program exits.
 797  * If file already exists, fail.
 798  */
 799 static int record_pid(void)
 800 {
 801         char pid[20];
 802         int fd;
 803
 804         snprintf(pid, 20, "%d\n", getpid());
 805         fd = open("/var/run/sm-notify.pid", O_CREAT|O_EXCL|O_WRONLY, 0600);
 806         if (fd < 0)
 807                 return 0;
 808         if (write(fd, pid, strlen(pid)) != strlen(pid))  {
 809                 nsm_log(LOG_WARNING, "Writing to pid file failed: errno %d(%s)",
 810                         errno, strerror(errno));
 811         }
 812         close(fd);
 813         return 1;
 814 }
 815
 816 /* Drop privileges to match owner of state-directory
 817  * (in case a reply triggers some unknown bug).
 818  */
 819 static void drop_privs(void)
 820 {
 821         struct stat st;
 822
 823         if (stat(_SM_DIR_PATH, &st) == -1 &&
 824             stat(_SM_BASE_PATH, &st) == -1) {
 825                 st.st_uid = 0;
 826                 st.st_gid = 0;
 827         }
 828
 829         if (st.st_uid == 0) {
 830                 nsm_log(LOG_WARNING,
 831                         "sm-notify running as root. chown %s to choose different user",
 832                     _SM_DIR_PATH);
 833                 return;
 834         }
 835
 836         setgroups(0, NULL);
 837         if (setgid(st.st_gid) == -1
 838             || setuid(st.st_uid) == -1) {
 839                 nsm_log(LOG_ERR, "Fail to drop privileges");
 840                 exit(1);
 841         }
 842 }
 843
 844 static void set_kernel_nsm_state(int state)
 845 {
 846         int fd;
 847         const char *file = "/proc/sys/fs/nfs/nsm_local_state";
 848
 849         fd = open(file ,O_WRONLY);
 850         if (fd >= 0) {
 851                 char buf[20];
 852                 snprintf(buf, sizeof(buf), "%d", state);
 853                 if (write(fd, buf, strlen(buf)) != strlen(buf)) {
 854                         nsm_log(LOG_WARNING, "Writing to '%s' failed: errno %d (%s)",
 855                                 file, errno, strerror(errno));
 856                 }
 857                 close(fd);
 858         }
 859 }