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