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                 /* don't rotate if there is only one addrinfo */
 428                 if (host->ai->ai_next == NULL)
 429                         memcpy(&host->addr, host->ai->ai_addr,
 430                                                 host->ai->ai_addrlen);
 431                 else {
 432                         struct addrinfo *first = host->ai;
 433                         struct addrinfo **next = &host->ai;
 434
 435                         /* remove the first entry from the list */
 436                         host->ai = first->ai_next;
 437                         first->ai_next = NULL;
 438                         /* find the end of the list */
 439                         next = &first->ai_next;
 440                         while ( *next )
 441                                 next = & (*next)->ai_next;
 442                         /* put first entry at end */
 443                         *next = first;
 444                         memcpy(&host->addr, first->ai_addr,
 445                                                 first->ai_addrlen);
 446                 }
 447
 448                 smn_set_port((struct sockaddr *)&host->addr, 0);
 449                 host->retries = 0;
 450         }
 451
 452         memcpy(dest, &host->addr, destlen);
 453         if (smn_get_port(dest) == 0) {
 454                 /* Build a PMAP packet */
 455                 nsm_log(LOG_DEBUG, "Sending portmap query to %s", host->name);
 456
 457                 smn_set_port(dest, 111);
 458                 *p++ = htonl(100000);
 459                 *p++ = htonl(2);
 460                 *p++ = htonl(3);
 461
 462                 /* Auth and verf */
 463                 *p++ = 0; *p++ = 0;
 464                 *p++ = 0; *p++ = 0;
 465
 466                 *p++ = htonl(NSM_PROGRAM);
 467                 *p++ = htonl(NSM_VERSION);
 468                 *p++ = htonl(IPPROTO_UDP);
 469                 *p++ = 0;
 470         } else {
 471                 /* Build an SM_NOTIFY packet */
 472                 nsm_log(LOG_DEBUG, "Sending SM_NOTIFY to %s", host->name);
 473
 474                 *p++ = htonl(NSM_PROGRAM);
 475                 *p++ = htonl(NSM_VERSION);
 476                 *p++ = htonl(NSM_NOTIFY);
 477
 478                 /* Auth and verf */
 479                 *p++ = 0; *p++ = 0;
 480                 *p++ = 0; *p++ = 0;
 481
 482                 /* state change */
 483                 len = strlen(nsm_hostname);
 484                 *p++ = htonl(len);
 485                 memcpy(p, nsm_hostname, len);
 486                 p += (len + 3) >> 2;
 487                 *p++ = htonl(nsm_state);
 488         }
 489         len = (p - msgbuf) << 2;
 490
 491         if (sendto(sock, msgbuf, len, 0, dest, destlen) < 0)
 492                 nsm_log(LOG_WARNING, "Sending Reboot Notification to "
 493                         "'%s' failed: errno %d (%s)", host->name, errno, strerror(errno));
 494
 495         return 0;
 496 }
 497
 498 /*
 499  * Receive reply from remote host
 500  */
 501 static void
 502 recv_reply(int sock)
 503 {
 504         struct nsm_host *hp;
 505         struct sockaddr *sap;
 506         uint32_t        msgbuf[MAXMSGSIZE], *p, *end;
 507         uint32_t        xid;
 508         int             res;
 509
 510         res = recv(sock, msgbuf, sizeof(msgbuf), 0);
 511         if (res < 0)
 512                 return;
 513
 514         nsm_log(LOG_DEBUG, "Received packet...");
 515
 516         p = msgbuf;
 517         end = p + (res >> 2);
 518
 519         xid = ntohl(*p++);
 520         if (*p++ != htonl(1)    /* must be REPLY */
 521          || *p++ != htonl(0)    /* must be ACCEPTED */
 522          || *p++ != htonl(0)    /* must be NULL verifier */
 523          || *p++ != htonl(0)
 524          || *p++ != htonl(0))   /* must be SUCCESS */
 525                 return;
 526
 527         /* Before we look at the data, find the host struct for
 528            this reply */
 529         if ((hp = find_host(xid)) == NULL)
 530                 return;
 531         sap = (struct sockaddr *)&hp->addr;
 532
 533         if (smn_get_port(sap) == 0) {
 534                 /* This was a portmap request */
 535                 unsigned int    port;
 536
 537                 port = ntohl(*p++);
 538                 if (p > end)
 539                         goto fail;
 540
 541                 hp->send_next = time(NULL);
 542                 if (port == 0) {
 543                         /* No binding for statd. Delay the next
 544                          * portmap query for max timeout */
 545                         nsm_log(LOG_DEBUG, "No statd on %s", hp->name);
 546                         hp->timeout = NSM_MAX_TIMEOUT;
 547                         hp->send_next += NSM_MAX_TIMEOUT;
 548                 } else {
 549                         smn_set_port(sap, port);
 550                         if (hp->timeout >= NSM_MAX_TIMEOUT / 4)
 551                                 hp->timeout = NSM_MAX_TIMEOUT / 4;
 552                 }
 553                 hp->xid = 0;
 554         } else {
 555                 /* Successful NOTIFY call. Server returns void,
 556                  * so nothing we need to do here (except
 557                  * check that we didn't read past the end of the
 558                  * packet)
 559                  */
 560                 if (p <= end) {
 561                         nsm_log(LOG_DEBUG, "Host %s notified successfully",
 562                                         hp->name);
 563                         smn_forget_host(hp);
 564                         return;
 565                 }
 566         }
 567
 568 fail:   /* Re-insert the host */
 569         insert_host(hp);
 570 }
 571
 572 /*
 573  * Back up all hosts from the sm directory to sm.bak
 574  */
 575 static void
 576 backup_hosts(const char *dirname, const char *bakname)
 577 {
 578         struct dirent   *de;
 579         DIR             *dir;
 580
 581         if (!(dir = opendir(dirname))) {
 582                 nsm_log(LOG_WARNING,
 583                         "Failed to open %s: %s", dirname, strerror(errno));
 584                 return;
 585         }
 586
 587         while ((de = readdir(dir)) != NULL) {
 588                 char    src[1024], dst[1024];
 589
 590                 if (de->d_name[0] == '.')
 591                         continue;
 592
 593                 snprintf(src, sizeof(src), "%s/%s", dirname, de->d_name);
 594                 snprintf(dst, sizeof(dst), "%s/%s", bakname, de->d_name);
 595                 if (rename(src, dst) < 0) {
 596                         nsm_log(LOG_WARNING,
 597                                 "Failed to rename %s -> %s: %m",
 598                                 src, dst);
 599                 }
 600         }
 601         closedir(dir);
 602 }
 603
 604 /*
 605  * Get all entries from sm.bak and convert them to host entries
 606  */
 607 static void
 608 get_hosts(const char *dirname)
 609 {
 610         struct nsm_host *host;
 611         struct dirent   *de;
 612         DIR             *dir;
 613
 614         if (!(dir = opendir(dirname))) {
 615                 nsm_log(LOG_WARNING,
 616                         "Failed to open %s: %s", dirname, strerror(errno));
 617                 return;
 618         }
 619
 620         host = NULL;
 621         while ((de = readdir(dir)) != NULL) {
 622                 struct stat     stb;
 623                 char            path[1024];
 624
 625                 if (de->d_name[0] == '.')
 626                         continue;
 627                 if (host == NULL)
 628                         host = calloc(1, sizeof(*host));
 629                 if (host == NULL) {
 630                         nsm_log(LOG_WARNING, "Unable to allocate memory");
 631                         return;
 632                 }
 633
 634                 snprintf(path, sizeof(path), "%s/%s", dirname, de->d_name);
 635                 if (stat(path, &stb) < 0)
 636                         continue;
 637
 638                 host->last_used = stb.st_mtime;
 639                 host->timeout = NSM_TIMEOUT;
 640                 host->path = strdup(path);
 641                 host->name = strdup(de->d_name);
 642                 host->retries = 100; /* force address retry */
 643
 644                 insert_host(host);
 645                 host = NULL;
 646         }
 647         closedir(dir);
 648
 649         if (host)
 650                 free(host);
 651 }
 652
 653 /*
 654  * Insert host into sorted list
 655  */
 656 static void
 657 insert_host(struct nsm_host *host)
 658 {
 659         struct nsm_host **where, *p;
 660
 661         where = &hosts;
 662         while ((p = *where) != 0) {
 663                 /* Sort in ascending order of timeout */
 664                 if (host->send_next < p->send_next)
 665                         break;
 666                 /* If we have the same timeout, put the
 667                  * most recently used host first.
 668                  * This makes sure that "recent" hosts
 669                  * get notified first.
 670                  */
 671                 if (host->send_next == p->send_next
 672                  && host->last_used > p->last_used)
 673                         break;
 674                 where = &p->next;
 675         }
 676
 677         host->next = *where;
 678         *where = host;
 679 }
 680
 681 /*
 682  * Find host given the XID
 683  */
 684 static struct nsm_host *
 685 find_host(uint32_t xid)
 686 {
 687         struct nsm_host **where, *p;
 688
 689         where = &hosts;
 690         while ((p = *where) != 0) {
 691                 if (p->xid == xid) {
 692                         *where = p->next;
 693                         return p;
 694                 }
 695                 where = &p->next;
 696         }
 697         return NULL;
 698 }
 699
 700
 701 /*
 702  * Retrieve the current NSM state
 703  */
 704 static unsigned int
 705 nsm_get_state(int update)
 706 {
 707         char            newfile[PATH_MAX];
 708         int             fd, state;
 709
 710         if ((fd = open(_SM_STATE_PATH, O_RDONLY)) < 0) {
 711                 if (!opt_quiet) {
 712                         nsm_log(LOG_WARNING, "%s: %m", _SM_STATE_PATH);
 713                         nsm_log(LOG_WARNING, "Creating %s, set initial state 1",
 714                                 _SM_STATE_PATH);
 715                 }
 716                 state = 1;
 717                 update = 1;
 718         } else {
 719                 if (read(fd, &state, sizeof(state)) != sizeof(state)) {
 720                         nsm_log(LOG_WARNING,
 721                                 "%s: bad file size, setting state = 1",
 722                                 _SM_STATE_PATH);
 723                         state = 1;
 724                         update = 1;
 725                 } else {
 726                         if (!(state & 1))
 727                                 state += 1;
 728                 }
 729                 close(fd);
 730         }
 731
 732         if (update) {
 733                 state += 2;
 734                 snprintf(newfile, sizeof(newfile),
 735                                 "%s.new", _SM_STATE_PATH);
 736                 if ((fd = open(newfile, O_CREAT|O_WRONLY, 0644)) < 0) {
 737                         nsm_log(LOG_ERR, "Cannot create %s: %m", newfile);
 738                         exit(1);
 739                 }
 740                 if (write(fd, &state, sizeof(state)) != sizeof(state)) {
 741                         nsm_log(LOG_ERR,
 742                                 "Failed to write state to %s", newfile);
 743                         exit(1);
 744                 }
 745                 close(fd);
 746                 if (rename(newfile, _SM_STATE_PATH) < 0) {
 747                         nsm_log(LOG_ERR,
 748                                 "Cannot create %s: %m", _SM_STATE_PATH);
 749                         exit(1);
 750                 }
 751                 sync();
 752         }
 753
 754         return state;
 755 }
 756
 757 /*
 758  * Log a message
 759  */
 760 static void
 761 nsm_log(int fac, const char *fmt, ...)
 762 {
 763         va_list ap;
 764
 765         if (fac == LOG_DEBUG && !opt_debug)
 766                 return;
 767
 768         va_start(ap, fmt);
 769         if (log_syslog)
 770                 vsyslog(fac, fmt, ap);
 771         else {
 772                 vfprintf(stderr, fmt, ap);
 773                 fputs("\n", stderr);
 774         }
 775         va_end(ap);
 776 }
 777
 778 /*
 779  * Record pid in /var/run/sm-notify.pid
 780  * This file should remain until a reboot, even if the
 781  * program exits.
 782  * If file already exists, fail.
 783  */
 784 static int record_pid(void)
 785 {
 786         char pid[20];
 787         int fd;
 788
 789         snprintf(pid, 20, "%d\n", getpid());
 790         fd = open("/var/run/sm-notify.pid", O_CREAT|O_EXCL|O_WRONLY, 0600);
 791         if (fd < 0)
 792                 return 0;
 793         if (write(fd, pid, strlen(pid)) != strlen(pid))  {
 794                 nsm_log(LOG_WARNING, "Writing to pid file failed: errno %d(%s)",
 795                         errno, strerror(errno));
 796         }
 797         close(fd);
 798         return 1;
 799 }
 800
 801 /* Drop privileges to match owner of state-directory
 802  * (in case a reply triggers some unknown bug).
 803  */
 804 static void drop_privs(void)
 805 {
 806         struct stat st;
 807
 808         if (stat(_SM_DIR_PATH, &st) == -1 &&
 809             stat(_SM_BASE_PATH, &st) == -1) {
 810                 st.st_uid = 0;
 811                 st.st_gid = 0;
 812         }
 813
 814         if (st.st_uid == 0) {
 815                 nsm_log(LOG_WARNING,
 816                         "sm-notify running as root. chown %s to choose different user",
 817                     _SM_DIR_PATH);
 818                 return;
 819         }
 820
 821         setgroups(0, NULL);
 822         if (setgid(st.st_gid) == -1
 823             || setuid(st.st_uid) == -1) {
 824                 nsm_log(LOG_ERR, "Fail to drop privileges");
 825                 exit(1);
 826         }
 827 }
 828
 829 static void set_kernel_nsm_state(int state)
 830 {
 831         int fd;
 832         const char *file = "/proc/sys/fs/nfs/nsm_local_state";
 833
 834         fd = open(file ,O_WRONLY);
 835         if (fd >= 0) {
 836                 char buf[20];
 837                 snprintf(buf, sizeof(buf), "%d", state);
 838                 if (write(fd, buf, strlen(buf)) != strlen(buf)) {
 839                         nsm_log(LOG_WARNING, "Writing to '%s' failed: errno %d (%s)",
 840                                 file, errno, strerror(errno));
 841                 }
 842                 close(fd);
 843         }
 844 }