utils/mountd/cache.c

   1
   2 /*
   3  * Handle communication with knfsd internal cache
   4  *
   5  * We open /proc/net/rpc/{auth.unix.ip,nfsd.export,nfsd.fh}/channel
   6  * and listen for requests (using my_svc_run)
   7  *
   8  */
   9
  10 #ifdef HAVE_CONFIG_H
  11 #include <config.h>
  12 #endif
  13
  14 #include <sys/types.h>
  15 #include <sys/select.h>
  16 #include <sys/stat.h>
  17 #include <time.h>
  18 #include <netinet/in.h>
  19 #include <arpa/inet.h>
  20 #include <unistd.h>
  21 #include <fcntl.h>
  22 #include <errno.h>
  23 #include <ctype.h>
  24 #include <pwd.h>
  25 #include <grp.h>
  26 #include "misc.h"
  27 #include "nfslib.h"
  28 #include "exportfs.h"
  29 #include "mountd.h"
  30 #include "xmalloc.h"
  31 #include "fsloc.h"
  32
  33 #include "blkid/blkid.h"
  34
  35
  36 enum nfsd_fsid {
  37         FSID_DEV = 0,
  38         FSID_NUM,
  39         FSID_MAJOR_MINOR,
  40         FSID_ENCODE_DEV,
  41         FSID_UUID4_INUM,
  42         FSID_UUID8,
  43         FSID_UUID16,
  44         FSID_UUID16_INUM,
  45 };
  46
  47 /*
  48  * Support routines for text-based upcalls.
  49  * Fields are separated by spaces.
  50  * Fields are either mangled to quote space tab newline slosh with slosh
  51  * or a hexified with a leading \x
  52  * Record is terminated with newline.
  53  *
  54  */
  55 int cache_export_ent(char *domain, struct exportent *exp, char *p);
  56
  57
  58 char *lbuf  = NULL;
  59 int lbuflen = 0;
  60
  61 void auth_unix_ip(FILE *f)
  62 {
  63         /* requests are
  64          *  class IP-ADDR
  65          * Ignore if class != "nfsd"
  66          * Otherwise find domainname and write back:
  67          *
  68          *  "nfsd" IP-ADDR expiry domainname
  69          */
  70         char *cp;
  71         char class[20];
  72         char ipaddr[20];
  73         char *client;
  74         struct in_addr addr;
  75         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
  76                 return;
  77
  78         cp = lbuf;
  79
  80         if (qword_get(&cp, class, 20) <= 0 ||
  81             strcmp(class, "nfsd") != 0)
  82                 return;
  83
  84         if (qword_get(&cp, ipaddr, 20) <= 0)
  85                 return;
  86
  87         if (inet_aton(ipaddr, &addr)==0)
  88                 return;
  89
  90         auth_reload();
  91
  92         /* addr is a valid, interesting address, find the domain name... */
  93         client = client_compose(addr);
  94
  95
  96         qword_print(f, "nfsd");
  97         qword_print(f, ipaddr);
  98         qword_printint(f, time(0)+30*60);
  99         if (client)
 100                 qword_print(f, *client?client:"DEFAULT");
 101         qword_eol(f);
 102
 103         if (client) free(client);
 104
 105 }
 106
 107 void auth_unix_gid(FILE *f)
 108 {
 109         /* Request are
 110          *  uid
 111          * reply is
 112          *  uid expiry count list of group ids
 113          */
 114         int uid;
 115         struct passwd *pw;
 116         gid_t glist[100], *groups = glist;
 117         int ngroups = 100;
 118         int rv, i;
 119         char *cp;
 120
 121         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 122                 return;
 123
 124         cp = lbuf;
 125         if (qword_get_int(&cp, &uid) != 0)
 126                 return;
 127
 128         pw = getpwuid(uid);
 129         if (!pw)
 130                 rv = -1;
 131         else {
 132                 rv = getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups);
 133                 if (rv == -1 && ngroups >= 100) {
 134                         groups = malloc(sizeof(gid_t)*ngroups);
 135                         if (!groups)
 136                                 rv = -1;
 137                         else
 138                                 rv = getgrouplist(pw->pw_name, pw->pw_gid,
 139                                                   groups, &ngroups);
 140                 }
 141         }
 142         qword_printint(f, uid);
 143         qword_printint(f, time(0)+30*60);
 144         if (rv >= 0) {
 145                 qword_printint(f, ngroups);
 146                 for (i=0; i<ngroups; i++)
 147                         qword_printint(f, groups[i]);
 148         }
 149         qword_eol(f);
 150         if (groups != glist)
 151                 free(groups);
 152 }
 153
 154 int get_uuid(char *path, char *uuid, int uuidlen, char *u)
 155 {
 156         /* extract hex digits from uuidstr and compose a uuid
 157          * of the given length (max 16), xoring bytes to make
 158          * a smaller uuid.  Then compare with uuid
 159          */
 160         int i = 0;
 161         const char *val;
 162
 163         if (path) {
 164                 static blkid_cache cache = NULL;
 165                 struct stat stb;
 166                 char *devname;
 167                 blkid_tag_iterate iter;
 168                 blkid_dev dev;
 169                 const char *type;
 170                 if (cache == NULL)
 171                         blkid_get_cache(&cache, NULL);
 172
 173                 blkid_probe_all_new(cache);
 174
 175                 if (stat(path, &stb) != 0)
 176                         return 0;
 177                 devname = blkid_devno_to_devname(stb.st_dev);
 178                 if (!devname)
 179                         return 0;
 180                 dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
 181                 free(devname);
 182                 if (!dev)
 183                         return 0;
 184                 iter = blkid_tag_iterate_begin(dev);
 185                 if (!iter)
 186                         return 0;
 187                 while (blkid_tag_next(iter, &type, &val) == 0)
 188                         if (strcmp(type, "UUID") == 0)
 189                                 break;
 190                 blkid_tag_iterate_end(iter);
 191                 if (!type)
 192                         return 0;
 193         } else {
 194                 val = uuid;
 195         }
 196
 197         memset(u, 0, uuidlen);
 198         for ( ; *val ; val++) {
 199                 char c = *val;
 200                 if (!isxdigit(c))
 201                         continue;
 202                 if (isalpha(c)) {
 203                         if (isupper(c))
 204                                 c = c - 'A' + 10;
 205                         else
 206                                 c = c - 'a' + 10;
 207                 } else
 208                         c = c - '0' + 0;
 209                 if ((i&1) == 0)
 210                         c <<= 4;
 211                 u[i/2] ^= c;
 212                 i++;
 213                 if (i == uuidlen*2)
 214                         i = 0;
 215         }
 216         return 1;
 217 }
 218
 219
 220 void nfsd_fh(FILE *f)
 221 {
 222         /* request are:
 223          *  domain fsidtype fsid
 224          * interpret fsid, find export point and options, and write:
 225          *  domain fsidtype fsid expiry path
 226          */
 227         char *cp;
 228         char *dom;
 229         int fsidtype;
 230         int fsidlen;
 231         unsigned int dev, major=0, minor=0;
 232         unsigned int inode=0;
 233         unsigned long long inode64;
 234         unsigned int fsidnum=0;
 235         char fsid[32];
 236         struct exportent *found = NULL;
 237         nfs_export *exp;
 238         int i;
 239         int dev_missing = 0;
 240         int uuidlen = 0;
 241         char *fhuuid = NULL;
 242
 243         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 244                 return;
 245
 246         cp = lbuf;
 247
 248         dom = malloc(strlen(cp));
 249         if (dom == NULL)
 250                 return;
 251         if (qword_get(&cp, dom, strlen(cp)) <= 0)
 252                 goto out;
 253         if (qword_get_int(&cp, &fsidtype) != 0)
 254                 goto out;
 255         if (fsidtype < 0 || fsidtype > 7)
 256                 goto out; /* unknown type */
 257         if ((fsidlen = qword_get(&cp, fsid, 32)) <= 0)
 258                 goto out;
 259         switch(fsidtype) {
 260         case FSID_DEV: /* 4 bytes: 2 major, 2 minor, 4 inode */
 261                 if (fsidlen != 8)
 262                         goto out;
 263                 memcpy(&dev, fsid, 4);
 264                 memcpy(&inode, fsid+4, 4);
 265                 major = ntohl(dev)>>16;
 266                 minor = ntohl(dev) & 0xFFFF;
 267                 break;
 268
 269         case FSID_NUM: /* 4 bytes - fsid */
 270                 if (fsidlen != 4)
 271                         goto out;
 272                 memcpy(&fsidnum, fsid, 4);
 273                 break;
 274
 275         case FSID_MAJOR_MINOR: /* 12 bytes: 4 major, 4 minor, 4 inode
 276                  * This format is never actually used but was
 277                  * an historical accident
 278                  */
 279                 if (fsidlen != 12)
 280                         goto out;
 281                 memcpy(&dev, fsid, 4); major = ntohl(dev);
 282                 memcpy(&dev, fsid+4, 4); minor = ntohl(dev);
 283                 memcpy(&inode, fsid+8, 4);
 284                 break;
 285
 286         case FSID_ENCODE_DEV: /* 8 bytes: 4 byte packed device number, 4 inode */
 287                 /* This is *host* endian, not net-byte-order, because
 288                  * no-one outside this host has any business interpreting it
 289                  */
 290                 if (fsidlen != 8)
 291                         goto out;
 292                 memcpy(&dev, fsid, 4);
 293                 memcpy(&inode, fsid+4, 4);
 294                 major = (dev & 0xfff00) >> 8;
 295                 minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
 296                 break;
 297
 298         case FSID_UUID4_INUM: /* 4 byte inode number and 4 byte uuid */
 299                 if (fsidlen != 8)
 300                         goto out;
 301                 memcpy(&inode, fsid, 4);
 302                 uuidlen = 4;
 303                 fhuuid = fsid+4;
 304                 break;
 305         case FSID_UUID8: /* 8 byte uuid */
 306                 if (fsidlen != 8)
 307                         goto out;
 308                 uuidlen = 8;
 309                 fhuuid = fsid;
 310                 break;
 311         case FSID_UUID16: /* 16 byte uuid */
 312                 if (fsidlen != 16)
 313                         goto out;
 314                 uuidlen = 16;
 315                 fhuuid = fsid;
 316                 break;
 317         case FSID_UUID16_INUM: /* 8 byte inode number and 16 byte uuid */
 318                 if (fsidlen != 24)
 319                         goto out;
 320                 memcpy(&inode64, fsid, 8);
 321                 inode = inode64;
 322                 uuidlen = 16;
 323                 fhuuid = fsid+8;
 324                 break;
 325         }
 326
 327         auth_reload();
 328
 329         /* Now determine export point for this fsid/domain */
 330         for (i=0 ; i < MCL_MAXTYPES; i++) {
 331                 for (exp = exportlist[i]; exp; exp = exp->m_next) {
 332                         struct stat stb;
 333                         char u[16];
 334
 335                         if (!client_member(dom, exp->m_client->m_hostname))
 336                                 continue;
 337                         if (exp->m_export.e_mountpoint &&
 338                             !is_mountpoint(exp->m_export.e_mountpoint[0]?
 339                                            exp->m_export.e_mountpoint:
 340                                            exp->m_export.e_path))
 341                                 dev_missing ++;
 342                         if (stat(exp->m_export.e_path, &stb) != 0)
 343                                 continue;
 344                         switch(fsidtype){
 345                         case FSID_DEV:
 346                         case FSID_MAJOR_MINOR:
 347                         case FSID_ENCODE_DEV:
 348                                 if (stb.st_ino != inode)
 349                                         continue;
 350                                 if (major != major(stb.st_dev) ||
 351                                     minor != minor(stb.st_dev))
 352                                         continue;
 353                                 break;
 354                         case FSID_NUM:
 355                                 if (((exp->m_export.e_flags & NFSEXP_FSID) == 0 ||
 356                                      exp->m_export.e_fsid != fsidnum))
 357                                         continue;
 358                                 break;
 359                         case FSID_UUID4_INUM:
 360                         case FSID_UUID16_INUM:
 361                                 if (stb.st_ino != inode)
 362                                         continue;
 363                                 goto check_uuid;
 364                         case FSID_UUID8:
 365                         case FSID_UUID16:
 366                                 if (!is_mountpoint(exp->m_export.e_path))
 367                                         continue;
 368                         check_uuid:
 369                                 if (exp->m_export.e_uuid)
 370                                         get_uuid(NULL, exp->m_export.e_uuid,
 371                                                  uuidlen, u);
 372                                 else if (get_uuid(exp->m_export.e_path, NULL,
 373                                                   uuidlen, u) == 0)
 374                                         continue;
 375
 376                                 if (memcmp(u, fhuuid, uuidlen) != 0)
 377                                         continue;
 378                                 break;
 379                         }
 380                         /* It's a match !! */
 381                         if (!found)
 382                                 found = &exp->m_export;
 383                         else if (strcmp(found->e_path, exp->m_export.e_path)!= 0)
 384                         {
 385                                 xlog(L_WARNING, "%s and %s have same filehandle for %s, using first",
 386                                      found->e_path, exp->m_export.e_path, dom);
 387                         }
 388                 }
 389         }
 390         if (found &&
 391             found->e_mountpoint &&
 392             !is_mountpoint(found->e_mountpoint[0]?
 393                            found->e_mountpoint:
 394                            found->e_path)) {
 395                 /* Cannot export this yet
 396                  * should log a warning, but need to rate limit
 397                    xlog(L_WARNING, "%s not exported as %d not a mountpoint",
 398                    found->e_path, found->e_mountpoint);
 399                  */
 400                 /* FIXME we need to make sure we re-visit this later */
 401                 goto out;
 402         }
 403         if (!found && dev_missing) {
 404                 /* The missing dev could be what we want, so just be
 405                  * quite rather than returning stale yet
 406                  */
 407                 goto out;
 408         }
 409
 410         if (found)
 411                 cache_export_ent(dom, found, found->e_path);
 412
 413         qword_print(f, dom);
 414         qword_printint(f, fsidtype);
 415         qword_printhex(f, fsid, fsidlen);
 416         /* The fsid -> path lookup can be quite expensive as it
 417          * potentially stats and reads lots of devices, and some of those
 418          * might have spun-down.  The Answer is not likely to
 419          * change underneath us, and an 'exportfs -f' can always
 420          * remove this from the kernel, so use a really log
 421          * timeout.  Maybe this should be configurable on the command
 422          * line.
 423          */
 424         qword_printint(f, 0x7fffffff);
 425         if (found)
 426                 qword_print(f, found->e_path);
 427         qword_eol(f);
 428  out:
 429         free(dom);
 430         return;
 431 }
 432
 433 static void write_fsloc(FILE *f, struct exportent *ep, char *path)
 434 {
 435         struct servers *servers;
 436
 437         if (ep->e_fslocmethod == FSLOC_NONE)
 438                 return;
 439
 440         servers = replicas_lookup(ep->e_fslocmethod, ep->e_fslocdata, path);
 441         if (!servers)
 442                 return;
 443         qword_print(f, "fsloc");
 444         qword_printint(f, servers->h_num);
 445         if (servers->h_num >= 0) {
 446                 int i;
 447                 for (i=0; i<servers->h_num; i++) {
 448                         qword_print(f, servers->h_mp[i]->h_host);
 449                         qword_print(f, servers->h_mp[i]->h_path);
 450                 }
 451         }
 452         qword_printint(f, servers->h_referral);
 453         release_replicas(servers);
 454 }
 455
 456 static int dump_to_cache(FILE *f, char *domain, char *path, struct exportent *exp)
 457 {
 458         qword_print(f, domain);
 459         qword_print(f, path);
 460         qword_printint(f, time(0)+30*60);
 461         if (exp) {
 462                 qword_printint(f, exp->e_flags);
 463                 qword_printint(f, exp->e_anonuid);
 464                 qword_printint(f, exp->e_anongid);
 465                 qword_printint(f, exp->e_fsid);
 466                 write_fsloc(f, exp, path);
 467                 if (exp->e_uuid == NULL) {
 468                         char u[16];
 469                         if (get_uuid(path, NULL, 16, u)) {
 470                                 qword_print(f, "uuid");
 471                                 qword_printhex(f, u, 16);
 472                         }
 473                 } else if (exp->e_uuid) {
 474                         qword_print(f, "uuid");
 475                         qword_printhex(f, exp->e_uuid, 16);
 476                 }
 477         }
 478         return qword_eol(f);
 479 }
 480
 481 void nfsd_export(FILE *f)
 482 {
 483         /* requests are:
 484          *  domain path
 485          * determine export options and return:
 486          *  domain path expiry flags anonuid anongid fsid
 487          */
 488
 489         char *cp;
 490         int i;
 491         char *dom, *path;
 492         nfs_export *exp, *found = NULL;
 493         int found_type = 0;
 494
 495
 496         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 497                 return;
 498
 499         cp = lbuf;
 500         dom = malloc(strlen(cp));
 501         path = malloc(strlen(cp));
 502
 503         if (!dom || !path)
 504                 goto out;
 505
 506         if (qword_get(&cp, dom, strlen(lbuf)) <= 0)
 507                 goto out;
 508         if (qword_get(&cp, path, strlen(lbuf)) <= 0)
 509                 goto out;
 510
 511         auth_reload();
 512
 513         /* now find flags for this export point in this domain */
 514         for (i=0 ; i < MCL_MAXTYPES; i++) {
 515                 for (exp = exportlist[i]; exp; exp = exp->m_next) {
 516                         if (!client_member(dom, exp->m_client->m_hostname))
 517                                 continue;
 518                         if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT) {
 519                                 /* if path is a mountpoint below e_path, then OK */
 520                                 int l = strlen(exp->m_export.e_path);
 521                                 if (strcmp(path, exp->m_export.e_path) == 0 ||
 522                                     (strncmp(path, exp->m_export.e_path, l) == 0 &&
 523                                      path[l] == '/' &&
 524                                      is_mountpoint(path)))
 525                                         /* ok */;
 526                                 else
 527                                         continue;
 528                         } else if (strcmp(path, exp->m_export.e_path) != 0)
 529                                 continue;
 530                         if (!found) {
 531                                 found = exp;
 532                                 found_type = i;
 533                                 continue;
 534                         }
 535                         /* If one is a CROSSMOUNT, then prefer the longest path */
 536                         if (((found->m_export.e_flags & NFSEXP_CROSSMOUNT) ||
 537                              (found->m_export.e_flags & NFSEXP_CROSSMOUNT)) &&
 538                             strlen(found->m_export.e_path) !=
 539                             strlen(found->m_export.e_path)) {
 540
 541                                 if (strlen(exp->m_export.e_path) >
 542                                     strlen(found->m_export.e_path)) {
 543                                         found = exp;
 544                                         found_type = i;
 545                                 }
 546                                 continue;
 547
 548                         } else if (found_type == i && found->m_warned == 0) {
 549                                 xlog(L_WARNING, "%s exported to both %s and %s, "
 550                                      "arbitrarily choosing options from first",
 551                                      path, found->m_client->m_hostname, exp->m_client->m_hostname,
 552                                      dom);
 553                                 found->m_warned = 1;
 554                         }
 555                 }
 556         }
 557
 558         if (found) {
 559                 dump_to_cache(f, dom, path, &found->m_export);
 560                 mountlist_add(dom, path);
 561         } else {
 562                 dump_to_cache(f, dom, path, NULL);
 563         }
 564  out:
 565         if (dom) free(dom);
 566         if (path) free(path);
 567 }
 568
 569
 570 struct {
 571         char *cache_name;
 572         void (*cache_handle)(FILE *f);
 573         FILE *f;
 574 } cachelist[] = {
 575         { "auth.unix.ip", auth_unix_ip},
 576         { "auth.unix.gid", auth_unix_gid},
 577         { "nfsd.export", nfsd_export},
 578         { "nfsd.fh", nfsd_fh},
 579         { NULL, NULL }
 580 };
 581
 582 extern int manage_gids;
 583 void cache_open(void)
 584 {
 585         int i;
 586         for (i=0; cachelist[i].cache_name; i++ ) {
 587                 char path[100];
 588                 if (!manage_gids && cachelist[i].cache_handle == auth_unix_gid)
 589                         continue;
 590                 sprintf(path, "/proc/net/rpc/%s/channel", cachelist[i].cache_name);
 591                 cachelist[i].f = fopen(path, "r+");
 592         }
 593 }
 594
 595 void cache_set_fds(fd_set *fdset)
 596 {
 597         int i;
 598         for (i=0; cachelist[i].cache_name; i++) {
 599                 if (cachelist[i].f)
 600                         FD_SET(fileno(cachelist[i].f), fdset);
 601         }
 602 }
 603
 604 int cache_process_req(fd_set *readfds)
 605 {
 606         int i;
 607         int cnt = 0;
 608         for (i=0; cachelist[i].cache_name; i++) {
 609                 if (cachelist[i].f != NULL &&
 610                     FD_ISSET(fileno(cachelist[i].f), readfds)) {
 611                         cnt++;
 612                         cachelist[i].cache_handle(cachelist[i].f);
 613                         FD_CLR(fileno(cachelist[i].f), readfds);
 614                 }
 615         }
 616         return cnt;
 617 }
 618
 619
 620 /*
 621  * Give IP->domain and domain+path->options to kernel
 622  * % echo nfsd $IP  $[now+30*60] $domain > /proc/net/rpc/auth.unix.ip/channel
 623  * % echo $domain $path $[now+30*60] $options $anonuid $anongid $fsid > /proc/net/rpc/nfsd.export/channel
 624  */
 625
 626 int cache_export_ent(char *domain, struct exportent *exp, char *path)
 627 {
 628         int err;
 629         FILE *f = fopen("/proc/net/rpc/nfsd.export/channel", "w");
 630         if (!f)
 631                 return -1;
 632
 633         err = dump_to_cache(f, domain, exp->e_path, exp);
 634         mountlist_add(domain, exp->e_path);
 635
 636         while ((exp->e_flags & NFSEXP_CROSSMOUNT) && path) {
 637                 /* really an 'if', but we can break out of
 638                  * a 'while' more easily */
 639                 /* Look along 'path' for other filesystems
 640                  * and export them with the same options
 641                  */
 642                 struct stat stb;
 643                 int l = strlen(exp->e_path);
 644                 int dev;
 645
 646                 if (strlen(path) <= l || path[l] != '/' ||
 647                     strncmp(exp->e_path, path, l) != 0)
 648                         break;
 649                 if (stat(exp->e_path, &stb) != 0)
 650                         break;
 651                 dev = stb.st_dev;
 652                 while(path[l] == '/') {
 653                         char c;
 654                         int err;
 655
 656                         l++;
 657                         while (path[l] != '/' && path[l])
 658                                 l++;
 659                         c = path[l];
 660                         path[l] = 0;
 661                         err = lstat(path, &stb);
 662                         path[l] = c;
 663                         if (err < 0)
 664                                 break;
 665                         if (stb.st_dev == dev)
 666                                 continue;
 667                         dev = stb.st_dev;
 668                         path[l] = 0;
 669                         dump_to_cache(f, domain, path, exp);
 670                         path[l] = c;
 671                 }
 672                 break;
 673         }
 674
 675         fclose(f);
 676         return err;
 677 }
 678
 679 int cache_export(nfs_export *exp, char *path)
 680 {
 681         int err;
 682         FILE *f;
 683
 684         f = fopen("/proc/net/rpc/auth.unix.ip/channel", "w");
 685         if (!f)
 686                 return -1;
 687
 688         qword_print(f, "nfsd");
 689         qword_print(f, inet_ntoa(exp->m_client->m_addrlist[0]));
 690         qword_printint(f, time(0)+30*60);
 691         qword_print(f, exp->m_client->m_hostname);
 692         err = qword_eol(f);
 693
 694         fclose(f);
 695
 696         err = cache_export_ent(exp->m_client->m_hostname, &exp->m_export, path)
 697                 || err;
 698         return err;
 699 }
 700
 701 /* Get a filehandle.
 702  * {
 703  *   echo $domain $path $length
 704  *   read filehandle <&0
 705  * } <> /proc/fs/nfsd/filehandle
 706  */
 707 struct nfs_fh_len *
 708 cache_get_filehandle(nfs_export *exp, int len, char *p)
 709 {
 710         FILE *f = fopen("/proc/fs/nfsd/filehandle", "r+");
 711         char buf[200];
 712         char *bp = buf;
 713         int failed;
 714         static struct nfs_fh_len fh;
 715
 716         if (!f)
 717                 f = fopen("/proc/fs/nfs/filehandle", "r+");
 718         if (!f)
 719                 return NULL;
 720
 721         qword_print(f, exp->m_client->m_hostname);
 722         qword_print(f, p);
 723         qword_printint(f, len);
 724         failed = qword_eol(f);
 725
 726         if (!failed)
 727                 failed = (fgets(buf, sizeof(buf), f) == NULL);
 728         fclose(f);
 729         if (failed)
 730                 return NULL;
 731         memset(fh.fh_handle, 0, sizeof(fh.fh_handle));
 732         fh.fh_size = qword_get(&bp, (char *)fh.fh_handle, NFS3_FHSIZE);
 733         return &fh;
 734 }
 735