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 <mntent.h>
  27 #include "misc.h"
  28 #include "nfslib.h"
  29 #include "exportfs.h"
  30 #include "mountd.h"
  31 #include "xmalloc.h"
  32 #include "fsloc.h"
  33 #include "pseudoflavors.h"
  34
  35 #ifdef USE_BLKID
  36 #include "blkid/blkid.h"
  37 #endif
  38
  39
  40 enum nfsd_fsid {
  41         FSID_DEV = 0,
  42         FSID_NUM,
  43         FSID_MAJOR_MINOR,
  44         FSID_ENCODE_DEV,
  45         FSID_UUID4_INUM,
  46         FSID_UUID8,
  47         FSID_UUID16,
  48         FSID_UUID16_INUM,
  49 };
  50
  51 /*
  52  * Support routines for text-based upcalls.
  53  * Fields are separated by spaces.
  54  * Fields are either mangled to quote space tab newline slosh with slosh
  55  * or a hexified with a leading \x
  56  * Record is terminated with newline.
  57  *
  58  */
  59 int cache_export_ent(char *domain, struct exportent *exp, char *p);
  60
  61
  62 char *lbuf  = NULL;
  63 int lbuflen = 0;
  64
  65 void auth_unix_ip(FILE *f)
  66 {
  67         /* requests are
  68          *  class IP-ADDR
  69          * Ignore if class != "nfsd"
  70          * Otherwise find domainname and write back:
  71          *
  72          *  "nfsd" IP-ADDR expiry domainname
  73          */
  74         char *cp;
  75         char class[20];
  76         char ipaddr[20];
  77         char *client;
  78         struct in_addr addr;
  79         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
  80                 return;
  81
  82         cp = lbuf;
  83
  84         if (qword_get(&cp, class, 20) <= 0 ||
  85             strcmp(class, "nfsd") != 0)
  86                 return;
  87
  88         if (qword_get(&cp, ipaddr, 20) <= 0)
  89                 return;
  90
  91         if (inet_aton(ipaddr, &addr)==0)
  92                 return;
  93
  94         auth_reload();
  95
  96         /* addr is a valid, interesting address, find the domain name... */
  97         client = client_compose(addr);
  98
  99
 100         qword_print(f, "nfsd");
 101         qword_print(f, ipaddr);
 102         qword_printint(f, time(0)+30*60);
 103         if (client)
 104                 qword_print(f, *client?client:"DEFAULT");
 105         qword_eol(f);
 106
 107         if (client) free(client);
 108
 109 }
 110
 111 void auth_unix_gid(FILE *f)
 112 {
 113         /* Request are
 114          *  uid
 115          * reply is
 116          *  uid expiry count list of group ids
 117          */
 118         int uid;
 119         struct passwd *pw;
 120         gid_t glist[100], *groups = glist;
 121         int ngroups = 100;
 122         int rv, i;
 123         char *cp;
 124
 125         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 126                 return;
 127
 128         cp = lbuf;
 129         if (qword_get_int(&cp, &uid) != 0)
 130                 return;
 131
 132         pw = getpwuid(uid);
 133         if (!pw)
 134                 rv = -1;
 135         else {
 136                 rv = getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups);
 137                 if (rv == -1 && ngroups >= 100) {
 138                         groups = malloc(sizeof(gid_t)*ngroups);
 139                         if (!groups)
 140                                 rv = -1;
 141                         else
 142                                 rv = getgrouplist(pw->pw_name, pw->pw_gid,
 143                                                   groups, &ngroups);
 144                 }
 145         }
 146         qword_printint(f, uid);
 147         qword_printint(f, time(0)+30*60);
 148         if (rv >= 0) {
 149                 qword_printint(f, ngroups);
 150                 for (i=0; i<ngroups; i++)
 151                         qword_printint(f, groups[i]);
 152         }
 153         qword_eol(f);
 154         if (groups != glist)
 155                 free(groups);
 156 }
 157
 158 #if USE_BLKID
 159 int get_uuid(char *path, char *uuid, int uuidlen, char *u)
 160 {
 161         /* extract hex digits from uuidstr and compose a uuid
 162          * of the given length (max 16), xoring bytes to make
 163          * a smaller uuid.  Then compare with uuid
 164          */
 165         int i = 0;
 166         const char *val;
 167
 168         if (path) {
 169                 static blkid_cache cache = NULL;
 170                 struct stat stb;
 171                 char *devname;
 172                 blkid_tag_iterate iter;
 173                 blkid_dev dev;
 174                 const char *type;
 175                 if (cache == NULL)
 176                         blkid_get_cache(&cache, NULL);
 177
 178                 blkid_probe_all_new(cache);
 179
 180                 if (stat(path, &stb) != 0)
 181                         return 0;
 182                 devname = blkid_devno_to_devname(stb.st_dev);
 183                 if (!devname)
 184                         return 0;
 185                 dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
 186                 free(devname);
 187                 if (!dev)
 188                         return 0;
 189                 iter = blkid_tag_iterate_begin(dev);
 190                 if (!iter)
 191                         return 0;
 192                 while (blkid_tag_next(iter, &type, &val) == 0)
 193                         if (strcmp(type, "UUID") == 0)
 194                                 break;
 195                 blkid_tag_iterate_end(iter);
 196                 if (!type)
 197                         return 0;
 198         } else {
 199                 val = uuid;
 200         }
 201
 202         memset(u, 0, uuidlen);
 203         for ( ; *val ; val++) {
 204                 char c = *val;
 205                 if (!isxdigit(c))
 206                         continue;
 207                 if (isalpha(c)) {
 208                         if (isupper(c))
 209                                 c = c - 'A' + 10;
 210                         else
 211                                 c = c - 'a' + 10;
 212                 } else
 213                         c = c - '0' + 0;
 214                 if ((i&1) == 0)
 215                         c <<= 4;
 216                 u[i/2] ^= c;
 217                 i++;
 218                 if (i == uuidlen*2)
 219                         i = 0;
 220         }
 221         return 1;
 222 }
 223 #endif
 224
 225 /* Iterate through /etc/mtab, finding mountpoints
 226  * at or below a given path
 227  */
 228 static char *next_mnt(void **v, char *p)
 229 {
 230         FILE *f;
 231         struct mntent *me;
 232         int l = strlen(p);
 233         if (*v == NULL) {
 234                 f = setmntent("/etc/mtab", "r");
 235                 *v = f;
 236         } else
 237                 f = *v;
 238         while ((me = getmntent(f)) != NULL &&
 239                (strncmp(me->mnt_dir, p, l) != 0 ||
 240                 me->mnt_dir[l] != '/'))
 241                 ;
 242         if (me == NULL) {
 243                 endmntent(f);
 244                 *v = NULL;
 245                 return NULL;
 246         }
 247         return me->mnt_dir;
 248 }
 249
 250 void nfsd_fh(FILE *f)
 251 {
 252         /* request are:
 253          *  domain fsidtype fsid
 254          * interpret fsid, find export point and options, and write:
 255          *  domain fsidtype fsid expiry path
 256          */
 257         char *cp;
 258         char *dom;
 259         int fsidtype;
 260         int fsidlen;
 261         unsigned int dev, major=0, minor=0;
 262         unsigned int inode=0;
 263         unsigned long long inode64;
 264         unsigned int fsidnum=0;
 265         char fsid[32];
 266         struct exportent *found = NULL;
 267         char *found_path = NULL;
 268         nfs_export *exp;
 269         int i;
 270         int dev_missing = 0;
 271         int uuidlen = 0;
 272         char *fhuuid = NULL;
 273
 274         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 275                 return;
 276
 277         cp = lbuf;
 278
 279         dom = malloc(strlen(cp));
 280         if (dom == NULL)
 281                 return;
 282         if (qword_get(&cp, dom, strlen(cp)) <= 0)
 283                 goto out;
 284         if (qword_get_int(&cp, &fsidtype) != 0)
 285                 goto out;
 286         if (fsidtype < 0 || fsidtype > 7)
 287                 goto out; /* unknown type */
 288         if ((fsidlen = qword_get(&cp, fsid, 32)) <= 0)
 289                 goto out;
 290         switch(fsidtype) {
 291         case FSID_DEV: /* 4 bytes: 2 major, 2 minor, 4 inode */
 292                 if (fsidlen != 8)
 293                         goto out;
 294                 memcpy(&dev, fsid, 4);
 295                 memcpy(&inode, fsid+4, 4);
 296                 major = ntohl(dev)>>16;
 297                 minor = ntohl(dev) & 0xFFFF;
 298                 break;
 299
 300         case FSID_NUM: /* 4 bytes - fsid */
 301                 if (fsidlen != 4)
 302                         goto out;
 303                 memcpy(&fsidnum, fsid, 4);
 304                 break;
 305
 306         case FSID_MAJOR_MINOR: /* 12 bytes: 4 major, 4 minor, 4 inode
 307                  * This format is never actually used but was
 308                  * an historical accident
 309                  */
 310                 if (fsidlen != 12)
 311                         goto out;
 312                 memcpy(&dev, fsid, 4); major = ntohl(dev);
 313                 memcpy(&dev, fsid+4, 4); minor = ntohl(dev);
 314                 memcpy(&inode, fsid+8, 4);
 315                 break;
 316
 317         case FSID_ENCODE_DEV: /* 8 bytes: 4 byte packed device number, 4 inode */
 318                 /* This is *host* endian, not net-byte-order, because
 319                  * no-one outside this host has any business interpreting it
 320                  */
 321                 if (fsidlen != 8)
 322                         goto out;
 323                 memcpy(&dev, fsid, 4);
 324                 memcpy(&inode, fsid+4, 4);
 325                 major = (dev & 0xfff00) >> 8;
 326                 minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
 327                 break;
 328
 329         case FSID_UUID4_INUM: /* 4 byte inode number and 4 byte uuid */
 330                 if (fsidlen != 8)
 331                         goto out;
 332                 memcpy(&inode, fsid, 4);
 333                 uuidlen = 4;
 334                 fhuuid = fsid+4;
 335                 break;
 336         case FSID_UUID8: /* 8 byte uuid */
 337                 if (fsidlen != 8)
 338                         goto out;
 339                 uuidlen = 8;
 340                 fhuuid = fsid;
 341                 break;
 342         case FSID_UUID16: /* 16 byte uuid */
 343                 if (fsidlen != 16)
 344                         goto out;
 345                 uuidlen = 16;
 346                 fhuuid = fsid;
 347                 break;
 348         case FSID_UUID16_INUM: /* 8 byte inode number and 16 byte uuid */
 349                 if (fsidlen != 24)
 350                         goto out;
 351                 memcpy(&inode64, fsid, 8);
 352                 inode = inode64;
 353                 uuidlen = 16;
 354                 fhuuid = fsid+8;
 355                 break;
 356         }
 357
 358         auth_reload();
 359
 360         /* Now determine export point for this fsid/domain */
 361         for (i=0 ; i < MCL_MAXTYPES; i++) {
 362                 nfs_export *next_exp;
 363                 for (exp = exportlist[i]; exp; exp = next_exp) {
 364                         struct stat stb;
 365                         char u[16];
 366                         char *path;
 367
 368                         if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT) {
 369                                 static nfs_export *prev = NULL;
 370                                 static void *mnt = NULL;
 371
 372                                 if (prev == exp) {
 373                                         /* try a submount */
 374                                         path = next_mnt(&mnt, exp->m_export.e_path);
 375                                         if (!path) {
 376                                                 next_exp = exp->m_next;
 377                                                 prev = NULL;
 378                                                 continue;
 379                                         }
 380                                         next_exp = exp;
 381                                 } else {
 382                                         prev = exp;
 383                                         mnt = NULL;
 384                                         path = exp->m_export.e_path;
 385                                         next_exp = exp;
 386                                 }
 387                         } else {
 388                                 path = exp->m_export.e_path;
 389                                 next_exp = exp->m_next;
 390                         }
 391
 392                         if (!client_member(dom, exp->m_client->m_hostname))
 393                                 continue;
 394                         if (exp->m_export.e_mountpoint &&
 395                             !is_mountpoint(exp->m_export.e_mountpoint[0]?
 396                                            exp->m_export.e_mountpoint:
 397                                            exp->m_export.e_path))
 398                                 dev_missing ++;
 399                         if (stat(path, &stb) != 0)
 400                                 continue;
 401                         if (!S_ISDIR(stb.st_mode) && !S_ISREG(stb.st_mode)) {
 402                                 continue;
 403                         }
 404                         switch(fsidtype){
 405                         case FSID_DEV:
 406                         case FSID_MAJOR_MINOR:
 407                         case FSID_ENCODE_DEV:
 408                                 if (stb.st_ino != inode)
 409                                         continue;
 410                                 if (major != major(stb.st_dev) ||
 411                                     minor != minor(stb.st_dev))
 412                                         continue;
 413                                 break;
 414                         case FSID_NUM:
 415                                 if (((exp->m_export.e_flags & NFSEXP_FSID) == 0 ||
 416                                      exp->m_export.e_fsid != fsidnum))
 417                                         continue;
 418                                 break;
 419                         case FSID_UUID4_INUM:
 420                         case FSID_UUID16_INUM:
 421                                 if (stb.st_ino != inode)
 422                                         continue;
 423                                 goto check_uuid;
 424                         case FSID_UUID8:
 425                         case FSID_UUID16:
 426                                 if (!is_mountpoint(path))
 427                                         continue;
 428                         check_uuid:
 429 #if USE_BLKID
 430                                 if (exp->m_export.e_uuid)
 431                                         get_uuid(NULL, exp->m_export.e_uuid,
 432                                                  uuidlen, u);
 433                                 else if (get_uuid(path, NULL,
 434                                                   uuidlen, u) == 0)
 435                                         continue;
 436
 437                                 if (memcmp(u, fhuuid, uuidlen) != 0)
 438                                         continue;
 439                                 break;
 440 #else
 441                                 continue;
 442 #endif
 443                         }
 444                         /* It's a match !! */
 445                         if (!found) {
 446                                 found = &exp->m_export;
 447                                 found_path = strdup(path);
 448                                 if (found_path == NULL)
 449                                         goto out;
 450                         } else if (strcmp(found->e_path, exp->m_export.e_path)!= 0)
 451                         {
 452                                 xlog(L_WARNING, "%s and %s have same filehandle for %s, using first",
 453                                      found_path, path, dom);
 454                         }
 455                 }
 456         }
 457         if (found &&
 458             found->e_mountpoint &&
 459             !is_mountpoint(found->e_mountpoint[0]?
 460                            found->e_mountpoint:
 461                            found->e_path)) {
 462                 /* Cannot export this yet
 463                  * should log a warning, but need to rate limit
 464                    xlog(L_WARNING, "%s not exported as %d not a mountpoint",
 465                    found->e_path, found->e_mountpoint);
 466                  */
 467                 /* FIXME we need to make sure we re-visit this later */
 468                 goto out;
 469         }
 470         if (!found && dev_missing) {
 471                 /* The missing dev could be what we want, so just be
 472                  * quite rather than returning stale yet
 473                  */
 474                 goto out;
 475         }
 476
 477         if (found)
 478                 if (cache_export_ent(dom, found, found_path) < 0)
 479                         found = 0;
 480
 481         qword_print(f, dom);
 482         qword_printint(f, fsidtype);
 483         qword_printhex(f, fsid, fsidlen);
 484         /* The fsid -> path lookup can be quite expensive as it
 485          * potentially stats and reads lots of devices, and some of those
 486          * might have spun-down.  The Answer is not likely to
 487          * change underneath us, and an 'exportfs -f' can always
 488          * remove this from the kernel, so use a really log
 489          * timeout.  Maybe this should be configurable on the command
 490          * line.
 491          */
 492         qword_printint(f, 0x7fffffff);
 493         if (found)
 494                 qword_print(f, found->e_path);
 495         qword_eol(f);
 496  out:
 497         free(found_path);
 498         free(dom);
 499         return;
 500 }
 501
 502 static void write_fsloc(FILE *f, struct exportent *ep, char *path)
 503 {
 504         struct servers *servers;
 505
 506         if (ep->e_fslocmethod == FSLOC_NONE)
 507                 return;
 508
 509         servers = replicas_lookup(ep->e_fslocmethod, ep->e_fslocdata, path);
 510         if (!servers)
 511                 return;
 512         qword_print(f, "fsloc");
 513         qword_printint(f, servers->h_num);
 514         if (servers->h_num >= 0) {
 515                 int i;
 516                 for (i=0; i<servers->h_num; i++) {
 517                         qword_print(f, servers->h_mp[i]->h_host);
 518                         qword_print(f, servers->h_mp[i]->h_path);
 519                 }
 520         }
 521         qword_printint(f, servers->h_referral);
 522         release_replicas(servers);
 523 }
 524
 525 static void write_secinfo(FILE *f, struct exportent *ep)
 526 {
 527         struct sec_entry *p;
 528
 529         for (p = ep->e_secinfo; p->flav; p++)
 530                 ; /* Do nothing */
 531         if (p == ep->e_secinfo) {
 532                 /* There was no sec= option */
 533                 return;
 534         }
 535         qword_print(f, "secinfo");
 536         qword_printint(f, p - ep->e_secinfo);
 537         for (p = ep->e_secinfo; p->flav; p++) {
 538                 qword_printint(f, p->flav->fnum);
 539                 qword_printint(f, p->flags);
 540         }
 541
 542 }
 543
 544 static int dump_to_cache(FILE *f, char *domain, char *path, struct exportent *exp)
 545 {
 546         qword_print(f, domain);
 547         qword_print(f, path);
 548         qword_printint(f, time(0)+30*60);
 549         if (exp) {
 550                 qword_printint(f, exp->e_flags);
 551                 qword_printint(f, exp->e_anonuid);
 552                 qword_printint(f, exp->e_anongid);
 553                 qword_printint(f, exp->e_fsid);
 554                 write_fsloc(f, exp, path);
 555                 write_secinfo(f, exp);
 556 #if USE_BLKID
 557                 if (exp->e_uuid == NULL) {
 558                         char u[16];
 559                         if (get_uuid(path, NULL, 16, u)) {
 560                                 qword_print(f, "uuid");
 561                                 qword_printhex(f, u, 16);
 562                         }
 563                 } else if (exp->e_uuid) {
 564                         qword_print(f, "uuid");
 565                         qword_printhex(f, exp->e_uuid, 16);
 566                 }
 567 #endif
 568         }
 569         return qword_eol(f);
 570 }
 571
 572 void nfsd_export(FILE *f)
 573 {
 574         /* requests are:
 575          *  domain path
 576          * determine export options and return:
 577          *  domain path expiry flags anonuid anongid fsid
 578          */
 579
 580         char *cp;
 581         int i;
 582         char *dom, *path;
 583         nfs_export *exp, *found = NULL;
 584         int found_type = 0;
 585
 586
 587         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 588                 return;
 589
 590         cp = lbuf;
 591         dom = malloc(strlen(cp));
 592         path = malloc(strlen(cp));
 593
 594         if (!dom || !path)
 595                 goto out;
 596
 597         if (qword_get(&cp, dom, strlen(lbuf)) <= 0)
 598                 goto out;
 599         if (qword_get(&cp, path, strlen(lbuf)) <= 0)
 600                 goto out;
 601
 602         auth_reload();
 603
 604         /* now find flags for this export point in this domain */
 605         for (i=0 ; i < MCL_MAXTYPES; i++) {
 606                 for (exp = exportlist[i]; exp; exp = exp->m_next) {
 607                         if (!client_member(dom, exp->m_client->m_hostname))
 608                                 continue;
 609                         if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT) {
 610                                 /* if path is a mountpoint below e_path, then OK */
 611                                 int l = strlen(exp->m_export.e_path);
 612                                 if (strcmp(path, exp->m_export.e_path) == 0 ||
 613                                     (strncmp(path, exp->m_export.e_path, l) == 0 &&
 614                                      path[l] == '/' &&
 615                                      is_mountpoint(path)))
 616                                         /* ok */;
 617                                 else
 618                                         continue;
 619                         } else if (strcmp(path, exp->m_export.e_path) != 0)
 620                                 continue;
 621                         if (!found) {
 622                                 found = exp;
 623                                 found_type = i;
 624                                 continue;
 625                         }
 626                         /* If one is a CROSSMOUNT, then prefer the longest path */
 627                         if (((found->m_export.e_flags & NFSEXP_CROSSMOUNT) ||
 628                              (found->m_export.e_flags & NFSEXP_CROSSMOUNT)) &&
 629                             strlen(found->m_export.e_path) !=
 630                             strlen(found->m_export.e_path)) {
 631
 632                                 if (strlen(exp->m_export.e_path) >
 633                                     strlen(found->m_export.e_path)) {
 634                                         found = exp;
 635                                         found_type = i;
 636                                 }
 637                                 continue;
 638
 639                         } else if (found_type == i && found->m_warned == 0) {
 640                                 xlog(L_WARNING, "%s exported to both %s and %s, "
 641                                      "arbitrarily choosing options from first",
 642                                      path, found->m_client->m_hostname, exp->m_client->m_hostname,
 643                                      dom);
 644                                 found->m_warned = 1;
 645                         }
 646                 }
 647         }
 648
 649         if (found) {
 650                 if (dump_to_cache(f, dom, path, &found->m_export) < 0) {
 651                         xlog(L_WARNING,
 652                              "Cannot export %s, possibly unsupported filesystem"
 653                              " or fsid= required", path);
 654                         dump_to_cache(f, dom, path, NULL);
 655                 }
 656         } else {
 657                 dump_to_cache(f, dom, path, NULL);
 658         }
 659  out:
 660         if (dom) free(dom);
 661         if (path) free(path);
 662 }
 663
 664
 665 struct {
 666         char *cache_name;
 667         void (*cache_handle)(FILE *f);
 668         FILE *f;
 669 } cachelist[] = {
 670         { "auth.unix.ip", auth_unix_ip},
 671         { "auth.unix.gid", auth_unix_gid},
 672         { "nfsd.export", nfsd_export},
 673         { "nfsd.fh", nfsd_fh},
 674         { NULL, NULL }
 675 };
 676
 677 extern int manage_gids;
 678 void cache_open(void)
 679 {
 680         int i;
 681         for (i=0; cachelist[i].cache_name; i++ ) {
 682                 char path[100];
 683                 if (!manage_gids && cachelist[i].cache_handle == auth_unix_gid)
 684                         continue;
 685                 sprintf(path, "/proc/net/rpc/%s/channel", cachelist[i].cache_name);
 686                 cachelist[i].f = fopen(path, "r+");
 687         }
 688 }
 689
 690 void cache_set_fds(fd_set *fdset)
 691 {
 692         int i;
 693         for (i=0; cachelist[i].cache_name; i++) {
 694                 if (cachelist[i].f)
 695                         FD_SET(fileno(cachelist[i].f), fdset);
 696         }
 697 }
 698
 699 int cache_process_req(fd_set *readfds)
 700 {
 701         int i;
 702         int cnt = 0;
 703         for (i=0; cachelist[i].cache_name; i++) {
 704                 if (cachelist[i].f != NULL &&
 705                     FD_ISSET(fileno(cachelist[i].f), readfds)) {
 706                         cnt++;
 707                         cachelist[i].cache_handle(cachelist[i].f);
 708                         FD_CLR(fileno(cachelist[i].f), readfds);
 709                 }
 710         }
 711         return cnt;
 712 }
 713
 714
 715 /*
 716  * Give IP->domain and domain+path->options to kernel
 717  * % echo nfsd $IP  $[now+30*60] $domain > /proc/net/rpc/auth.unix.ip/channel
 718  * % echo $domain $path $[now+30*60] $options $anonuid $anongid $fsid > /proc/net/rpc/nfsd.export/channel
 719  */
 720
 721 int cache_export_ent(char *domain, struct exportent *exp, char *path)
 722 {
 723         int err;
 724         FILE *f = fopen("/proc/net/rpc/nfsd.export/channel", "w");
 725         if (!f)
 726                 return -1;
 727
 728         err = dump_to_cache(f, domain, exp->e_path, exp);
 729         if (err) {
 730                 xlog(L_WARNING,
 731                      "Cannot export %s, possibly unsupported filesystem or"
 732                      " fsid= required", exp->e_path);
 733         }
 734
 735         while (err == 0 && (exp->e_flags & NFSEXP_CROSSMOUNT) && path) {
 736                 /* really an 'if', but we can break out of
 737                  * a 'while' more easily */
 738                 /* Look along 'path' for other filesystems
 739                  * and export them with the same options
 740                  */
 741                 struct stat stb;
 742                 int l = strlen(exp->e_path);
 743                 int dev;
 744
 745                 if (strlen(path) <= l || path[l] != '/' ||
 746                     strncmp(exp->e_path, path, l) != 0)
 747                         break;
 748                 if (stat(exp->e_path, &stb) != 0)
 749                         break;
 750                 dev = stb.st_dev;
 751                 while(path[l] == '/') {
 752                         char c;
 753                         /* errors for submount should fail whole filesystem */
 754                         int err2;
 755
 756                         l++;
 757                         while (path[l] != '/' && path[l])
 758                                 l++;
 759                         c = path[l];
 760                         path[l] = 0;
 761                         err2 = lstat(path, &stb);
 762                         path[l] = c;
 763                         if (err2 < 0)
 764                                 break;
 765                         if (stb.st_dev == dev)
 766                                 continue;
 767                         dev = stb.st_dev;
 768                         path[l] = 0;
 769                         dump_to_cache(f, domain, path, exp);
 770                         path[l] = c;
 771                 }
 772                 break;
 773         }
 774
 775         fclose(f);
 776         return err;
 777 }
 778
 779 int cache_export(nfs_export *exp, char *path)
 780 {
 781         int err;
 782         FILE *f;
 783
 784         f = fopen("/proc/net/rpc/auth.unix.ip/channel", "w");
 785         if (!f)
 786                 return -1;
 787
 788         qword_print(f, "nfsd");
 789         qword_print(f, inet_ntoa(exp->m_client->m_addrlist[0]));
 790         qword_printint(f, time(0)+30*60);
 791         qword_print(f, exp->m_client->m_hostname);
 792         err = qword_eol(f);
 793
 794         fclose(f);
 795
 796         err = cache_export_ent(exp->m_client->m_hostname, &exp->m_export, path)
 797                 || err;
 798         return err;
 799 }
 800
 801 /* Get a filehandle.
 802  * {
 803  *   echo $domain $path $length
 804  *   read filehandle <&0
 805  * } <> /proc/fs/nfsd/filehandle
 806  */
 807 struct nfs_fh_len *
 808 cache_get_filehandle(nfs_export *exp, int len, char *p)
 809 {
 810         FILE *f = fopen("/proc/fs/nfsd/filehandle", "r+");
 811         char buf[200];
 812         char *bp = buf;
 813         int failed;
 814         static struct nfs_fh_len fh;
 815
 816         if (!f)
 817                 f = fopen("/proc/fs/nfs/filehandle", "r+");
 818         if (!f)
 819                 return NULL;
 820
 821         qword_print(f, exp->m_client->m_hostname);
 822         qword_print(f, p);
 823         qword_printint(f, len);
 824         failed = qword_eol(f);
 825
 826         if (!failed)
 827                 failed = (fgets(buf, sizeof(buf), f) == NULL);
 828         fclose(f);
 829         if (failed)
 830                 return NULL;
 831         memset(fh.fh_handle, 0, sizeof(fh.fh_handle));
 832         fh.fh_size = qword_get(&bp, (char *)fh.fh_handle, NFS3_FHSIZE);
 833         return &fh;
 834 }
 835