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