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 <sys/vfs.h>
  18 #include <time.h>
  19 #include <netinet/in.h>
  20 #include <arpa/inet.h>
  21 #include <unistd.h>
  22 #include <fcntl.h>
  23 #include <errno.h>
  24 #include <ctype.h>
  25 #include <pwd.h>
  26 #include <grp.h>
  27 #include <mntent.h>
  28 #include "misc.h"
  29 #include "nfslib.h"
  30 #include "exportfs.h"
  31 #include "mountd.h"
  32 #include "fsloc.h"
  33 #include "pseudoflavors.h"
  34
  35 #ifdef USE_BLKID
  36 #include "blkid/blkid.h"
  37 #endif
  38
  39 /*
  40  * Invoked by RPC service loop
  41  */
  42 void    cache_set_fds(fd_set *fdset);
  43 int     cache_process_req(fd_set *readfds);
  44
  45 enum nfsd_fsid {
  46         FSID_DEV = 0,
  47         FSID_NUM,
  48         FSID_MAJOR_MINOR,
  49         FSID_ENCODE_DEV,
  50         FSID_UUID4_INUM,
  51         FSID_UUID8,
  52         FSID_UUID16,
  53         FSID_UUID16_INUM,
  54 };
  55
  56 /*
  57  * Support routines for text-based upcalls.
  58  * Fields are separated by spaces.
  59  * Fields are either mangled to quote space tab newline slosh with slosh
  60  * or a hexified with a leading \x
  61  * Record is terminated with newline.
  62  *
  63  */
  64 static int cache_export_ent(char *domain, struct exportent *exp, char *p);
  65
  66 #define INITIAL_MANAGED_GROUPS 100
  67
  68 char *lbuf  = NULL;
  69 int lbuflen = 0;
  70 extern int use_ipaddr;
  71
  72 static void auth_unix_ip(FILE *f)
  73 {
  74         /* requests are
  75          *  class IP-ADDR
  76          * Ignore if class != "nfsd"
  77          * Otherwise find domainname and write back:
  78          *
  79          *  "nfsd" IP-ADDR expiry domainname
  80          */
  81         char *cp;
  82         char class[20];
  83         char ipaddr[INET6_ADDRSTRLEN];
  84         char *client = NULL;
  85         struct addrinfo *tmp = NULL;
  86         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
  87                 return;
  88
  89         xlog(D_CALL, "auth_unix_ip: inbuf '%s'", lbuf);
  90
  91         cp = lbuf;
  92
  93         if (qword_get(&cp, class, 20) <= 0 ||
  94             strcmp(class, "nfsd") != 0)
  95                 return;
  96
  97         if (qword_get(&cp, ipaddr, sizeof(ipaddr)) <= 0)
  98                 return;
  99
 100         tmp = host_pton(ipaddr);
 101         if (tmp == NULL)
 102                 return;
 103
 104         auth_reload();
 105
 106         /* addr is a valid, interesting address, find the domain name... */
 107         if (!use_ipaddr) {
 108                 struct addrinfo *ai = NULL;
 109
 110                 ai = client_resolve(tmp->ai_addr);
 111                 if (ai) {
 112                         client = client_compose(ai);
 113                         freeaddrinfo(ai);
 114                 }
 115         }
 116         qword_print(f, "nfsd");
 117         qword_print(f, ipaddr);
 118         qword_printtimefrom(f, DEFAULT_TTL);
 119         if (use_ipaddr)
 120                 qword_print(f, ipaddr);
 121         else if (client)
 122                 qword_print(f, *client?client:"DEFAULT");
 123         qword_eol(f);
 124         xlog(D_CALL, "auth_unix_ip: client %p '%s'", client, client?client: "DEFAULT");
 125
 126         free(client);
 127         freeaddrinfo(tmp);
 128
 129 }
 130
 131 static void auth_unix_gid(FILE *f)
 132 {
 133         /* Request are
 134          *  uid
 135          * reply is
 136          *  uid expiry count list of group ids
 137          */
 138         uid_t uid;
 139         struct passwd *pw;
 140         static gid_t *groups = NULL;
 141         static int groups_len = 0;
 142         gid_t *more_groups;
 143         int ngroups;
 144         int rv, i;
 145         char *cp;
 146
 147         if (groups_len == 0) {
 148                 groups = malloc(sizeof(gid_t) * INITIAL_MANAGED_GROUPS);
 149                 if (!groups)
 150                         return;
 151
 152                 groups_len = INITIAL_MANAGED_GROUPS;
 153         }
 154
 155         ngroups = groups_len;
 156
 157         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 158                 return;
 159
 160         cp = lbuf;
 161         if (qword_get_uint(&cp, &uid) != 0)
 162                 return;
 163
 164         pw = getpwuid(uid);
 165         if (!pw)
 166                 rv = -1;
 167         else {
 168                 rv = getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups);
 169                 if (rv == -1 && ngroups >= groups_len) {
 170                         more_groups = realloc(groups, sizeof(gid_t)*ngroups);
 171                         if (!more_groups)
 172                                 rv = -1;
 173                         else {
 174                                 groups = more_groups;
 175                                 groups_len = ngroups;
 176                                 rv = getgrouplist(pw->pw_name, pw->pw_gid,
 177                                                   groups, &ngroups);
 178                         }
 179                 }
 180         }
 181         qword_printuint(f, uid);
 182         qword_printtimefrom(f, DEFAULT_TTL);
 183         if (rv >= 0) {
 184                 qword_printuint(f, ngroups);
 185                 for (i=0; i<ngroups; i++)
 186                         qword_printuint(f, groups[i]);
 187         } else
 188                 qword_printuint(f, 0);
 189         qword_eol(f);
 190 }
 191
 192 #if USE_BLKID
 193 static const char *get_uuid_blkdev(char *path)
 194 {
 195         /* We set *safe if we know that we need the
 196          * fsid from statfs too.
 197          */
 198         static blkid_cache cache = NULL;
 199         struct stat stb;
 200         char *devname;
 201         blkid_tag_iterate iter;
 202         blkid_dev dev;
 203         const char *type;
 204         const char *val, *uuid = NULL;
 205
 206         if (cache == NULL)
 207                 blkid_get_cache(&cache, NULL);
 208
 209         if (stat(path, &stb) != 0)
 210                 return NULL;
 211         devname = blkid_devno_to_devname(stb.st_dev);
 212         if (!devname)
 213                 return NULL;
 214         dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
 215         free(devname);
 216         if (!dev)
 217                 return NULL;
 218         iter = blkid_tag_iterate_begin(dev);
 219         if (!iter)
 220                 return NULL;
 221         while (blkid_tag_next(iter, &type, &val) == 0) {
 222                 if (strcmp(type, "UUID") == 0)
 223                         uuid = val;
 224                 if (strcmp(type, "TYPE") == 0 &&
 225                     strcmp(val, "btrfs") == 0) {
 226                         uuid = NULL;
 227                         break;
 228                 }
 229         }
 230         blkid_tag_iterate_end(iter);
 231         return uuid;
 232 }
 233 #else
 234 #define get_uuid_blkdev(path) (NULL)
 235 #endif
 236
 237 static int get_uuid(const char *val, size_t uuidlen, char *u)
 238 {
 239         /* extract hex digits from uuidstr and compose a uuid
 240          * of the given length (max 16), xoring bytes to make
 241          * a smaller uuid.
 242          */
 243         size_t i = 0;
 244
 245         memset(u, 0, uuidlen);
 246         for ( ; *val ; val++) {
 247                 int c = *val;
 248                 if (!isxdigit(c))
 249                         continue;
 250                 if (isalpha(c)) {
 251                         if (isupper(c))
 252                                 c = c - 'A' + 10;
 253                         else
 254                                 c = c - 'a' + 10;
 255                 } else
 256                         c = c - '0' + 0;
 257                 if ((i&1) == 0)
 258                         c <<= 4;
 259                 u[i/2] ^= (char)c;
 260                 i++;
 261                 if (i == uuidlen*2)
 262                         i = 0;
 263         }
 264         return 1;
 265 }
 266
 267 static int uuid_by_path(char *path, int type, size_t uuidlen, char *uuid)
 268 {
 269         /* get a uuid for the filesystem found at 'path'.
 270          * There are several possible ways of generating the
 271          * uuids (types).
 272          * Type 0 is used for new filehandles, while other types
 273          * may be used to interpret old filehandle - to ensure smooth
 274          * forward migration.
 275          * We return 1 if a uuid was found (and it might be worth
 276          * trying the next type) or 0 if no more uuid types can be
 277          * extracted.
 278          */
 279
 280         /* Possible sources of uuid are
 281          * - blkid uuid
 282          * - statfs64 uuid
 283          *
 284          * On some filesystems (e.g. vfat) the statfs64 uuid is simply an
 285          * encoding of the device that the filesystem is mounted from, so
 286          * it we be very bad to use that (as device numbers change).  blkid
 287          * must be preferred.
 288          * On other filesystems (e.g. btrfs) the statfs64 uuid contains
 289          * important info that the blkid uuid cannot contain:  This happens
 290          * when multiple subvolumes are exported (they have the same
 291          * blkid uuid but different statfs64 uuids).
 292          * We rely on get_uuid_blkdev *knowing* which is which and not returning
 293          * a uuid for filesystems where the statfs64 uuid is better.
 294          *
 295          */
 296         struct statfs64 st;
 297         char fsid_val[17];
 298         const char *blkid_val;
 299         const char *val;
 300
 301         blkid_val = get_uuid_blkdev(path);
 302
 303         if (statfs64(path, &st) == 0 &&
 304             (st.f_fsid.__val[0] || st.f_fsid.__val[1]))
 305                 snprintf(fsid_val, 17, "%08x%08x",
 306                          st.f_fsid.__val[0], st.f_fsid.__val[1]);
 307         else
 308                 fsid_val[0] = 0;
 309
 310         if (blkid_val && (type--) == 0)
 311                 val = blkid_val;
 312         else if (fsid_val[0] && (type--) == 0)
 313                 val = fsid_val;
 314         else
 315                 return 0;
 316
 317         get_uuid(val, uuidlen, uuid);
 318         return 1;
 319 }
 320
 321 /* Iterate through /etc/mtab, finding mountpoints
 322  * at or below a given path
 323  */
 324 static char *next_mnt(void **v, char *p)
 325 {
 326         FILE *f;
 327         struct mntent *me;
 328         size_t l = strlen(p);
 329         if (*v == NULL) {
 330                 f = setmntent("/etc/mtab", "r");
 331                 *v = f;
 332         } else
 333                 f = *v;
 334         while ((me = getmntent(f)) != NULL &&
 335                (strncmp(me->mnt_dir, p, l) != 0 ||
 336                 me->mnt_dir[l] != '/'))
 337                 ;
 338         if (me == NULL) {
 339                 endmntent(f);
 340                 *v = NULL;
 341                 return NULL;
 342         }
 343         return me->mnt_dir;
 344 }
 345
 346 static int is_subdirectory(char *child, char *parent)
 347 {
 348         size_t l = strlen(parent);
 349
 350         if (strcmp(parent, "/") == 0)
 351                 return 1;
 352
 353         return strcmp(child, parent) == 0
 354                 || (strncmp(child, parent, l) == 0 && child[l] == '/');
 355 }
 356
 357 static int path_matches(nfs_export *exp, char *path)
 358 {
 359         if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT)
 360                 return is_subdirectory(path, exp->m_export.e_path);
 361         return strcmp(path, exp->m_export.e_path) == 0;
 362 }
 363
 364 static int
 365 export_matches(nfs_export *exp, char *dom, char *path, struct addrinfo *ai)
 366 {
 367         return path_matches(exp, path) && client_matches(exp, dom, ai);
 368 }
 369
 370 /* True iff e1 is a child of e2 and e2 has crossmnt set: */
 371 static bool subexport(struct exportent *e1, struct exportent *e2)
 372 {
 373         char *p1 = e1->e_path, *p2 = e2->e_path;
 374         size_t l2 = strlen(p2);
 375
 376         return e2->e_flags & NFSEXP_CROSSMOUNT
 377                 && strncmp(p1, p2, l2) == 0
 378                 && p1[l2] == '/';
 379 }
 380
 381 struct parsed_fsid {
 382         int fsidtype;
 383         /* We could use a union for this, but it would be more
 384          * complicated; why bother? */
 385         unsigned int inode;
 386         unsigned int minor;
 387         unsigned int major;
 388         unsigned int fsidnum;
 389         size_t uuidlen;
 390         char *fhuuid;
 391 };
 392
 393 static int parse_fsid(int fsidtype, int fsidlen, char *fsid,
 394                 struct parsed_fsid *parsed)
 395 {
 396         unsigned int dev;
 397         unsigned long long inode64;
 398
 399         memset(parsed, 0, sizeof(*parsed));
 400         parsed->fsidtype = fsidtype;
 401         switch(fsidtype) {
 402         case FSID_DEV: /* 4 bytes: 2 major, 2 minor, 4 inode */
 403                 if (fsidlen != 8)
 404                         return -1;
 405                 memcpy(&dev, fsid, 4);
 406                 memcpy(&parsed->inode, fsid+4, 4);
 407                 parsed->major = ntohl(dev)>>16;
 408                 parsed->minor = ntohl(dev) & 0xFFFF;
 409                 break;
 410
 411         case FSID_NUM: /* 4 bytes - fsid */
 412                 if (fsidlen != 4)
 413                         return -1;
 414                 memcpy(&parsed->fsidnum, fsid, 4);
 415                 break;
 416
 417         case FSID_MAJOR_MINOR: /* 12 bytes: 4 major, 4 minor, 4 inode
 418                  * This format is never actually used but was
 419                  * an historical accident
 420                  */
 421                 if (fsidlen != 12)
 422                         return -1;
 423                 memcpy(&dev, fsid, 4);
 424                 parsed->major = ntohl(dev);
 425                 memcpy(&dev, fsid+4, 4);
 426                 parsed->minor = ntohl(dev);
 427                 memcpy(&parsed->inode, fsid+8, 4);
 428                 break;
 429
 430         case FSID_ENCODE_DEV: /* 8 bytes: 4 byte packed device number, 4 inode */
 431                 /* This is *host* endian, not net-byte-order, because
 432                  * no-one outside this host has any business interpreting it
 433                  */
 434                 if (fsidlen != 8)
 435                         return -1;
 436                 memcpy(&dev, fsid, 4);
 437                 memcpy(&parsed->inode, fsid+4, 4);
 438                 parsed->major = (dev & 0xfff00) >> 8;
 439                 parsed->minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
 440                 break;
 441
 442         case FSID_UUID4_INUM: /* 4 byte inode number and 4 byte uuid */
 443                 if (fsidlen != 8)
 444                         return -1;
 445                 memcpy(&parsed->inode, fsid, 4);
 446                 parsed->uuidlen = 4;
 447                 parsed->fhuuid = fsid+4;
 448                 break;
 449         case FSID_UUID8: /* 8 byte uuid */
 450                 if (fsidlen != 8)
 451                         return -1;
 452                 parsed->uuidlen = 8;
 453                 parsed->fhuuid = fsid;
 454                 break;
 455         case FSID_UUID16: /* 16 byte uuid */
 456                 if (fsidlen != 16)
 457                         return -1;
 458                 parsed->uuidlen = 16;
 459                 parsed->fhuuid = fsid;
 460                 break;
 461         case FSID_UUID16_INUM: /* 8 byte inode number and 16 byte uuid */
 462                 if (fsidlen != 24)
 463                         return -1;
 464                 memcpy(&inode64, fsid, 8);
 465                 parsed->inode = inode64;
 466                 parsed->uuidlen = 16;
 467                 parsed->fhuuid = fsid+8;
 468                 break;
 469         }
 470         return 0;
 471 }
 472
 473 static bool match_fsid(struct parsed_fsid *parsed, nfs_export *exp, char *path)
 474 {
 475         struct stat stb;
 476         int type;
 477         char u[16];
 478
 479         if (stat(path, &stb) != 0)
 480                 return false;
 481         if (!S_ISDIR(stb.st_mode) && !S_ISREG(stb.st_mode))
 482                 return false;
 483
 484         switch (parsed->fsidtype) {
 485         case FSID_DEV:
 486         case FSID_MAJOR_MINOR:
 487         case FSID_ENCODE_DEV:
 488                 if (stb.st_ino != parsed->inode)
 489                         return false;
 490                 if (parsed->major != major(stb.st_dev) ||
 491                     parsed->minor != minor(stb.st_dev))
 492                         return false;
 493                 return true;
 494         case FSID_NUM:
 495                 if (((exp->m_export.e_flags & NFSEXP_FSID) == 0 ||
 496                      exp->m_export.e_fsid != parsed->fsidnum))
 497                         return false;
 498                 return true;
 499         case FSID_UUID4_INUM:
 500         case FSID_UUID16_INUM:
 501                 if (stb.st_ino != parsed->inode)
 502                         return false;
 503                 goto check_uuid;
 504         case FSID_UUID8:
 505         case FSID_UUID16:
 506                 if (!is_mountpoint(path))
 507                         return false;
 508         check_uuid:
 509                 if (exp->m_export.e_uuid)
 510                         get_uuid(exp->m_export.e_uuid, parsed->uuidlen, u);
 511                 else
 512                         for (type = 0;
 513                              uuid_by_path(path, type, parsed->uuidlen, u);
 514                              type++)
 515                                 if (memcmp(u, parsed->fhuuid, parsed->uuidlen) == 0)
 516                                         return true;
 517
 518                 if (memcmp(u, parsed->fhuuid, parsed->uuidlen) != 0)
 519                         return false;
 520                 return true;
 521         }
 522         /* Well, unreachable, actually: */
 523         return false;
 524 }
 525
 526 static struct addrinfo *lookup_client_addr(char *dom)
 527 {
 528         struct addrinfo *ret;
 529         struct addrinfo *tmp;
 530
 531         dom++; /* skip initial "$" */
 532
 533         tmp = host_pton(dom);
 534         if (tmp == NULL)
 535                 return NULL;
 536         ret = client_resolve(tmp->ai_addr);
 537         freeaddrinfo(tmp);
 538         return ret;
 539 }
 540
 541 static void nfsd_fh(FILE *f)
 542 {
 543         /* request are:
 544          *  domain fsidtype fsid
 545          * interpret fsid, find export point and options, and write:
 546          *  domain fsidtype fsid expiry path
 547          */
 548         char *cp;
 549         char *dom;
 550         int fsidtype;
 551         int fsidlen;
 552         char fsid[32];
 553         struct parsed_fsid parsed;
 554         struct exportent *found = NULL;
 555         struct addrinfo *ai = NULL;
 556         char *found_path = NULL;
 557         nfs_export *exp;
 558         int i;
 559         int dev_missing = 0;
 560
 561         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 562                 return;
 563
 564         xlog(D_CALL, "nfsd_fh: inbuf '%s'", lbuf);
 565
 566         cp = lbuf;
 567
 568         dom = malloc(strlen(cp));
 569         if (dom == NULL)
 570                 return;
 571         if (qword_get(&cp, dom, strlen(cp)) <= 0)
 572                 goto out;
 573         if (qword_get_int(&cp, &fsidtype) != 0)
 574                 goto out;
 575         if (fsidtype < 0 || fsidtype > 7)
 576                 goto out; /* unknown type */
 577         if ((fsidlen = qword_get(&cp, fsid, 32)) <= 0)
 578                 goto out;
 579         if (parse_fsid(fsidtype, fsidlen, fsid, &parsed))
 580                 goto out;
 581
 582         auth_reload();
 583
 584         if (is_ipaddr_client(dom)) {
 585                 ai = lookup_client_addr(dom);
 586                 if (!ai)
 587                         goto out;
 588         }
 589
 590         /* Now determine export point for this fsid/domain */
 591         for (i=0 ; i < MCL_MAXTYPES; i++) {
 592                 nfs_export *next_exp;
 593                 for (exp = exportlist[i].p_head; exp; exp = next_exp) {
 594                         char *path;
 595
 596                         if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT) {
 597                                 static nfs_export *prev = NULL;
 598                                 static void *mnt = NULL;
 599
 600                                 if (prev == exp) {
 601                                         /* try a submount */
 602                                         path = next_mnt(&mnt, exp->m_export.e_path);
 603                                         if (!path) {
 604                                                 next_exp = exp->m_next;
 605                                                 prev = NULL;
 606                                                 continue;
 607                                         }
 608                                         next_exp = exp;
 609                                 } else {
 610                                         prev = exp;
 611                                         mnt = NULL;
 612                                         path = exp->m_export.e_path;
 613                                         next_exp = exp;
 614                                 }
 615                         } else {
 616                                 path = exp->m_export.e_path;
 617                                 next_exp = exp->m_next;
 618                         }
 619
 620                         if (!is_ipaddr_client(dom)
 621                                         && !namelist_client_matches(exp, dom))
 622                                 continue;
 623                         if (exp->m_export.e_mountpoint &&
 624                             !is_mountpoint(exp->m_export.e_mountpoint[0]?
 625                                            exp->m_export.e_mountpoint:
 626                                            exp->m_export.e_path))
 627                                 dev_missing ++;
 628
 629                         if (!match_fsid(&parsed, exp, path))
 630                                 continue;
 631                         if (is_ipaddr_client(dom)
 632                                         && !ipaddr_client_matches(exp, ai))
 633                                 continue;
 634                         if (!found || subexport(&exp->m_export, found)) {
 635                                 found = &exp->m_export;
 636                                 free(found_path);
 637                                 found_path = strdup(path);
 638                                 if (found_path == NULL)
 639                                         goto out;
 640                         } else if (strcmp(found->e_path, exp->m_export.e_path) != 0
 641                                    && !subexport(found, &exp->m_export))
 642                         {
 643                                 xlog(L_WARNING, "%s and %s have same filehandle for %s, using first",
 644                                      found_path, path, dom);
 645                         } else {
 646                                 /* same path, if one is V4ROOT, choose the other */
 647                                 if (found->e_flags & NFSEXP_V4ROOT) {
 648                                         found = &exp->m_export;
 649                                         free(found_path);
 650                                         found_path = strdup(path);
 651                                         if (found_path == NULL)
 652                                                 goto out;
 653                                 }
 654                         }
 655                 }
 656         }
 657         if (found &&
 658             found->e_mountpoint &&
 659             !is_mountpoint(found->e_mountpoint[0]?
 660                            found->e_mountpoint:
 661                            found->e_path)) {
 662                 /* Cannot export this yet
 663                  * should log a warning, but need to rate limit
 664                    xlog(L_WARNING, "%s not exported as %d not a mountpoint",
 665                    found->e_path, found->e_mountpoint);
 666                  */
 667                 /* FIXME we need to make sure we re-visit this later */
 668                 goto out;
 669         }
 670         if (!found && dev_missing) {
 671                 /* The missing dev could be what we want, so just be
 672                  * quite rather than returning stale yet
 673                  */
 674                 goto out;
 675         }
 676
 677         if (found)
 678                 if (cache_export_ent(dom, found, found_path) < 0)
 679                         found = 0;
 680
 681         qword_print(f, dom);
 682         qword_printint(f, fsidtype);
 683         qword_printhex(f, fsid, fsidlen);
 684         /* The fsid -> path lookup can be quite expensive as it
 685          * potentially stats and reads lots of devices, and some of those
 686          * might have spun-down.  The Answer is not likely to
 687          * change underneath us, and an 'exportfs -f' can always
 688          * remove this from the kernel, so use a really log
 689          * timeout.  Maybe this should be configurable on the command
 690          * line.
 691          */
 692         qword_printint(f, 0x7fffffff);
 693         if (found)
 694                 qword_print(f, found_path);
 695         qword_eol(f);
 696  out:
 697         if (found_path)
 698                 free(found_path);
 699         freeaddrinfo(ai);
 700         free(dom);
 701         xlog(D_CALL, "nfsd_fh: found %p path %s", found, found ? found->e_path : NULL);
 702         return;
 703 }
 704
 705 static void write_fsloc(FILE *f, struct exportent *ep)
 706 {
 707         struct servers *servers;
 708
 709         if (ep->e_fslocmethod == FSLOC_NONE)
 710                 return;
 711
 712         servers = replicas_lookup(ep->e_fslocmethod, ep->e_fslocdata);
 713         if (!servers)
 714                 return;
 715         qword_print(f, "fsloc");
 716         qword_printint(f, servers->h_num);
 717         if (servers->h_num >= 0) {
 718                 int i;
 719                 for (i=0; i<servers->h_num; i++) {
 720                         qword_print(f, servers->h_mp[i]->h_host);
 721                         qword_print(f, servers->h_mp[i]->h_path);
 722                 }
 723         }
 724         qword_printint(f, servers->h_referral);
 725         release_replicas(servers);
 726 }
 727
 728 static void write_secinfo(FILE *f, struct exportent *ep, int flag_mask)
 729 {
 730         struct sec_entry *p;
 731
 732         for (p = ep->e_secinfo; p->flav; p++)
 733                 ; /* Do nothing */
 734         if (p == ep->e_secinfo) {
 735                 /* There was no sec= option */
 736                 return;
 737         }
 738         qword_print(f, "secinfo");
 739         qword_printint(f, p - ep->e_secinfo);
 740         for (p = ep->e_secinfo; p->flav; p++) {
 741                 qword_printint(f, p->flav->fnum);
 742                 qword_printint(f, p->flags & flag_mask);
 743         }
 744
 745 }
 746
 747 static int dump_to_cache(FILE *f, char *domain, char *path, struct exportent *exp)
 748 {
 749         qword_print(f, domain);
 750         qword_print(f, path);
 751         if (exp) {
 752                 int different_fs = strcmp(path, exp->e_path) != 0;
 753                 int flag_mask = different_fs ? ~NFSEXP_FSID : ~0;
 754
 755                 qword_printtimefrom(f, exp->e_ttl);
 756                 qword_printint(f, exp->e_flags & flag_mask);
 757                 qword_printint(f, exp->e_anonuid);
 758                 qword_printint(f, exp->e_anongid);
 759                 qword_printint(f, exp->e_fsid);
 760                 write_fsloc(f, exp);
 761                 write_secinfo(f, exp, flag_mask);
 762                 if (exp->e_uuid == NULL || different_fs) {
 763                         char u[16];
 764                         if (uuid_by_path(path, 0, 16, u)) {
 765                                 qword_print(f, "uuid");
 766                                 qword_printhex(f, u, 16);
 767                         }
 768                 } else {
 769                         char u[16];
 770                         get_uuid(exp->e_uuid, 16, u);
 771                         qword_print(f, "uuid");
 772                         qword_printhex(f, u, 16);
 773                 }
 774         } else
 775                 qword_printtimefrom(f, DEFAULT_TTL);
 776         return qword_eol(f);
 777 }
 778
 779 static nfs_export *
 780 lookup_export(char *dom, char *path, struct addrinfo *ai)
 781 {
 782         nfs_export *exp;
 783         nfs_export *found = NULL;
 784         int found_type = 0;
 785         int i;
 786
 787         for (i=0 ; i < MCL_MAXTYPES; i++) {
 788                 for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
 789                         if (!export_matches(exp, dom, path, ai))
 790                                 continue;
 791                         if (!found) {
 792                                 found = exp;
 793                                 found_type = i;
 794                                 continue;
 795                         }
 796                         /* Always prefer non-V4ROOT exports */
 797                         if (exp->m_export.e_flags & NFSEXP_V4ROOT)
 798                                 continue;
 799                         if (found->m_export.e_flags & NFSEXP_V4ROOT) {
 800                                 found = exp;
 801                                 found_type = i;
 802                                 continue;
 803                         }
 804
 805                         /* If one is a CROSSMOUNT, then prefer the longest path */
 806                         if (((found->m_export.e_flags & NFSEXP_CROSSMOUNT) ||
 807                              (exp->m_export.e_flags & NFSEXP_CROSSMOUNT)) &&
 808                             strlen(found->m_export.e_path) !=
 809                             strlen(exp->m_export.e_path)) {
 810
 811                                 if (strlen(exp->m_export.e_path) >
 812                                     strlen(found->m_export.e_path)) {
 813                                         found = exp;
 814                                         found_type = i;
 815                                 }
 816                                 continue;
 817
 818                         } else if (found_type == i && found->m_warned == 0) {
 819                                 xlog(L_WARNING, "%s exported to both %s and %s, "
 820                                      "arbitrarily choosing options from first",
 821                                      path, found->m_client->m_hostname, exp->m_client->m_hostname,
 822                                      dom);
 823                                 found->m_warned = 1;
 824                         }
 825                 }
 826         }
 827         return found;
 828 }
 829
 830 #ifdef HAVE_NFS_PLUGIN_H
 831 #include <dlfcn.h>
 832 #include <link.h>
 833 #include <nfs-plugin.h>
 834
 835 /*
 836  * Find the export entry for the parent of "pathname".
 837  * Caller must not free returned exportent.
 838  */
 839 static struct exportent *lookup_parent_export(char *dom,
 840                 const char *pathname, struct addrinfo *ai)
 841 {
 842         char *parent, *slash;
 843         nfs_export *result;
 844
 845         parent = strdup(pathname);
 846         if (parent == NULL) {
 847                 xlog(D_GENERAL, "%s: failed to allocate parent path buffer",
 848                         __func__);
 849                 goto out_default;
 850         }
 851         xlog(D_CALL, "%s: pathname = '%s'", __func__, pathname);
 852
 853 again:
 854         /* shorten pathname by one component */
 855         slash = strrchr(parent, '/');
 856         if (slash == NULL) {
 857                 xlog(D_GENERAL, "%s: no slash found in pathname",
 858                         __func__);
 859                 goto out_default;
 860         }
 861         *slash = '\0';
 862
 863         if (strlen(parent) == 0) {
 864                 result = lookup_export(dom, "/", ai);
 865                 if (result == NULL) {
 866                         xlog(L_ERROR, "%s: no root export found.", __func__);
 867                         goto out_default;
 868                 }
 869                 goto out;
 870         }
 871
 872         result = lookup_export(dom, parent, ai);
 873         if (result == NULL) {
 874                 xlog(D_GENERAL, "%s: lookup_export(%s) found nothing",
 875                         __func__, parent);
 876                 goto again;
 877         }
 878
 879 out:
 880         xlog(D_CALL, "%s: found export for %s", __func__, parent);
 881         free(parent);
 882         return &result->m_export;
 883
 884 out_default:
 885         free(parent);
 886         return mkexportent("*", "/", "insecure");
 887 }
 888
 889 /*
 890  * Walk through a set of FS locations and build an e_fslocdata string.
 891  * Returns true if all went to plan; otherwise, false.
 892  */
 893 static bool locations_to_fslocdata(struct jp_ops *ops,
 894                 nfs_fsloc_set_t locations, char *fslocdata,
 895                 size_t remaining, int *ttl)
 896 {
 897         char *server, *last_path, *rootpath, *ptr;
 898         _Bool seen = false;
 899
 900         last_path = NULL;
 901         rootpath = NULL;
 902         server = NULL;
 903         ptr = fslocdata;
 904         *ttl = 0;
 905
 906         for (;;) {
 907                 enum jp_status status;
 908                 int len;
 909
 910                 status = ops->jp_get_next_location(locations, &server,
 911                                                         &rootpath, ttl);
 912                 if (status == JP_EMPTY)
 913                         break;
 914                 if (status != JP_OK) {
 915                         xlog(D_GENERAL, "%s: failed to parse location: %s",
 916                                 __func__, ops->jp_error(status));
 917                         goto out_false;
 918                 }
 919                 xlog(D_GENERAL, "%s: Location: %s:%s",
 920                         __func__, server, rootpath);
 921
 922                 if (last_path && strcmp(rootpath, last_path) == 0) {
 923                         len = snprintf(ptr, remaining, "+%s", server);
 924                         if (len < 0) {
 925                                 xlog(D_GENERAL, "%s: snprintf: %m", __func__);
 926                                 goto out_false;
 927                         }
 928                         if ((size_t)len >= remaining) {
 929                                 xlog(D_GENERAL, "%s: fslocdata buffer overflow", __func__);
 930                                 goto out_false;
 931                         }
 932                         remaining -= (size_t)len;
 933                         ptr += len;
 934                 } else {
 935                         if (last_path == NULL)
 936                                 len = snprintf(ptr, remaining, "%s@%s",
 937                                                         rootpath, server);
 938                         else
 939                                 len = snprintf(ptr, remaining, ":%s@%s",
 940                                                         rootpath, server);
 941                         if (len < 0) {
 942                                 xlog(D_GENERAL, "%s: snprintf: %m", __func__);
 943                                 goto out_false;
 944                         }
 945                         if ((size_t)len >= remaining) {
 946                                 xlog(D_GENERAL, "%s: fslocdata buffer overflow",
 947                                         __func__);
 948                                 goto out_false;
 949                         }
 950                         remaining -= (size_t)len;
 951                         ptr += len;
 952                         last_path = rootpath;
 953                 }
 954
 955                 seen = true;
 956                 free(rootpath);
 957                 free(server);
 958         }
 959
 960         xlog(D_CALL, "%s: fslocdata='%s', ttl=%d",
 961                 __func__, fslocdata, *ttl);
 962         return seen;
 963
 964 out_false:
 965         free(rootpath);
 966         free(server);
 967         return false;
 968 }
 969
 970 /*
 971  * Duplicate the junction's parent's export options and graft in
 972  * the fslocdata we constructed from the locations list.
 973  */
 974 static struct exportent *create_junction_exportent(struct exportent *parent,
 975                 const char *junction, const char *fslocdata, int ttl)
 976 {
 977         static struct exportent *eep;
 978
 979         eep = (struct exportent *)malloc(sizeof(*eep));
 980         if (eep == NULL)
 981                 goto out_nomem;
 982
 983         dupexportent(eep, parent);
 984         strcpy(eep->e_path, junction);
 985         eep->e_hostname = strdup(parent->e_hostname);
 986         if (eep->e_hostname == NULL) {
 987                 free(eep);
 988                 goto out_nomem;
 989         }
 990         free(eep->e_uuid);
 991         eep->e_uuid = NULL;
 992         eep->e_ttl = (unsigned int)ttl;
 993
 994         free(eep->e_fslocdata);
 995         eep->e_fslocdata = strdup(fslocdata);
 996         if (eep->e_fslocdata == NULL) {
 997                 free(eep->e_hostname);
 998                 free(eep);
 999                 goto out_nomem;
1000         }
1001         eep->e_fslocmethod = FSLOC_REFER;
1002         return eep;
1003
1004 out_nomem:
1005         xlog(L_ERROR, "%s: No memory", __func__);
1006         return NULL;
1007 }
1008
1009 /*
1010  * Walk through the set of FS locations and build an exportent.
1011  * Returns pointer to an exportent if "junction" refers to a junction.
1012  */
1013 static struct exportent *locations_to_export(struct jp_ops *ops,
1014                 nfs_fsloc_set_t locations, const char *junction,
1015                 struct exportent *parent)
1016 {
1017         static char fslocdata[BUFSIZ];
1018         int ttl;
1019
1020         fslocdata[0] = '\0';
1021         if (!locations_to_fslocdata(ops, locations,
1022                                         fslocdata, sizeof(fslocdata), &ttl))
1023                 return NULL;
1024         return create_junction_exportent(parent, junction, fslocdata, ttl);
1025 }
1026
1027 /*
1028  * Retrieve locations information in "junction" and dump it to the
1029  * kernel.  Returns pointer to an exportent if "junction" refers
1030  * to a junction.
1031  */
1032 static struct exportent *invoke_junction_ops(void *handle, char *dom,
1033                 const char *junction, struct addrinfo *ai)
1034 {
1035         struct exportent *parent, *exp = NULL;
1036         nfs_fsloc_set_t locations;
1037         enum jp_status status;
1038         struct jp_ops *ops;
1039         char *error;
1040
1041         ops = (struct jp_ops *)dlsym(handle, "nfs_junction_ops");
1042         error = dlerror();
1043         if (error != NULL) {
1044                 xlog(D_GENERAL, "%s: dlsym(jp_junction_ops): %s",
1045                         __func__, error);
1046                 return NULL;
1047         }
1048         if (ops->jp_api_version != JP_API_VERSION) {
1049                 xlog(D_GENERAL, "%s: unrecognized junction API version: %u",
1050                         __func__, ops->jp_api_version);
1051                 return NULL;
1052         }
1053
1054         status = ops->jp_init(false);
1055         if (status != JP_OK) {
1056                 xlog(D_GENERAL, "%s: failed to resolve %s: %s",
1057                         __func__, junction, ops->jp_error(status));
1058                 return NULL;
1059         }
1060
1061         status = ops->jp_get_locations(junction, &locations);
1062         switch (status) {
1063         case JP_OK:
1064                 break;
1065         case JP_NOTJUNCTION:
1066                 xlog(D_GENERAL, "%s: %s is not a junction",
1067                         __func__, junction);
1068                 goto out;
1069         default:
1070                 xlog(L_WARNING, "Dangling junction %s: %s",
1071                         junction, ops->jp_error(status));
1072                 goto out;
1073         }
1074
1075         parent = lookup_parent_export(dom, junction, ai);
1076         if (parent == NULL)
1077                 goto out;
1078
1079         exp = locations_to_export(ops, locations, junction, parent);
1080
1081         ops->jp_put_locations(locations);
1082
1083 out:
1084         ops->jp_done();
1085         return exp;
1086 }
1087
1088 /*
1089  * Load the junction plug-in, then try to resolve "pathname".
1090  * Returns pointer to an initialized exportent if "junction"
1091  * refers to a junction, or NULL if not.
1092  */
1093 static struct exportent *lookup_junction(char *dom, const char *pathname,
1094                 struct addrinfo *ai)
1095 {
1096         struct exportent *exp;
1097         struct link_map *map;
1098         void *handle;
1099
1100         handle = dlopen("libnfsjunct.so", RTLD_NOW);
1101         if (handle == NULL) {
1102                 xlog(D_GENERAL, "%s: dlopen: %s", __func__, dlerror());
1103                 return NULL;
1104         }
1105
1106         if (dlinfo(handle, RTLD_DI_LINKMAP, &map) == 0)
1107                 xlog(D_GENERAL, "%s: loaded plug-in %s",
1108                         __func__, map->l_name);
1109
1110         (void)dlerror();        /* Clear any error */
1111
1112         exp = invoke_junction_ops(handle, dom, pathname, ai);
1113
1114         /* We could leave it loaded to make junction resolution
1115          * faster next time.  However, if we want to replace the
1116          * library, that would require restarting mountd. */
1117         (void)dlclose(handle);
1118         return exp;
1119 }
1120
1121 static void lookup_nonexport(FILE *f, char *dom, char *path,
1122                 struct addrinfo *ai)
1123 {
1124         struct exportent *eep;
1125
1126         eep = lookup_junction(dom, path, ai);
1127         dump_to_cache(f, dom, path, eep);
1128         if (eep == NULL)
1129                 return;
1130         exportent_release(eep);
1131         free(eep);
1132 }
1133 #else   /* !HAVE_NFS_PLUGIN_H */
1134 static void lookup_nonexport(FILE *f, char *dom, char *path,
1135                 struct addrinfo *UNUSED(ai))
1136 {
1137         dump_to_cache(f, dom, path, NULL);
1138 }
1139 #endif  /* !HAVE_NFS_PLUGIN_H */
1140
1141 static void nfsd_export(FILE *f)
1142 {
1143         /* requests are:
1144          *  domain path
1145          * determine export options and return:
1146          *  domain path expiry flags anonuid anongid fsid
1147          */
1148
1149         char *cp;
1150         char *dom, *path;
1151         nfs_export *found = NULL;
1152         struct addrinfo *ai = NULL;
1153
1154         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
1155                 return;
1156
1157         xlog(D_CALL, "nfsd_export: inbuf '%s'", lbuf);
1158
1159         cp = lbuf;
1160         dom = malloc(strlen(cp));
1161         path = malloc(strlen(cp));
1162
1163         if (!dom || !path)
1164                 goto out;
1165
1166         if (qword_get(&cp, dom, strlen(lbuf)) <= 0)
1167                 goto out;
1168         if (qword_get(&cp, path, strlen(lbuf)) <= 0)
1169                 goto out;
1170
1171         auth_reload();
1172
1173         if (is_ipaddr_client(dom)) {
1174                 ai = lookup_client_addr(dom);
1175                 if (!ai)
1176                         goto out;
1177         }
1178
1179         found = lookup_export(dom, path, ai);
1180
1181         if (found) {
1182                 if (dump_to_cache(f, dom, path, &found->m_export) < 0) {
1183                         xlog(L_WARNING,
1184                              "Cannot export %s, possibly unsupported filesystem"
1185                              " or fsid= required", path);
1186                         dump_to_cache(f, dom, path, NULL);
1187                 }
1188         } else
1189                 lookup_nonexport(f, dom, path, ai);
1190
1191  out:
1192         xlog(D_CALL, "nfsd_export: found %p path %s", found, path ? path : NULL);
1193         if (dom) free(dom);
1194         if (path) free(path);
1195         freeaddrinfo(ai);
1196 }
1197
1198
1199 struct {
1200         char *cache_name;
1201         void (*cache_handle)(FILE *f);
1202         FILE *f;
1203         char vbuf[RPC_CHAN_BUF_SIZE];
1204 } cachelist[] = {
1205         { "auth.unix.ip", auth_unix_ip, NULL, ""},
1206         { "auth.unix.gid", auth_unix_gid, NULL, ""},
1207         { "nfsd.export", nfsd_export, NULL, ""},
1208         { "nfsd.fh", nfsd_fh, NULL, ""},
1209         { NULL, NULL, NULL, ""}
1210 };
1211
1212 extern int manage_gids;
1213
1214 /**
1215  * cache_open - prepare communications channels with kernel RPC caches
1216  *
1217  */
1218 void cache_open(void)
1219 {
1220         int i;
1221         for (i=0; cachelist[i].cache_name; i++ ) {
1222                 char path[100];
1223                 if (!manage_gids && cachelist[i].cache_handle == auth_unix_gid)
1224                         continue;
1225                 sprintf(path, "/proc/net/rpc/%s/channel", cachelist[i].cache_name);
1226                 cachelist[i].f = fopen(path, "r+");
1227                 if (cachelist[i].f != NULL) {
1228                         setvbuf(cachelist[i].f, cachelist[i].vbuf, _IOLBF,
1229                                 RPC_CHAN_BUF_SIZE);
1230                 }
1231         }
1232 }
1233
1234 /**
1235  * cache_set_fds - prepare cache file descriptors for one iteration of the service loop
1236  * @fdset: pointer to fd_set to prepare
1237  */
1238 void cache_set_fds(fd_set *fdset)
1239 {
1240         int i;
1241         for (i=0; cachelist[i].cache_name; i++) {
1242                 if (cachelist[i].f)
1243                         FD_SET(fileno(cachelist[i].f), fdset);
1244         }
1245 }
1246
1247 /**
1248  * cache_process_req - process any active cache file descriptors during service loop iteration
1249  * @fdset: pointer to fd_set to examine for activity
1250  */
1251 int cache_process_req(fd_set *readfds)
1252 {
1253         int i;
1254         int cnt = 0;
1255         for (i=0; cachelist[i].cache_name; i++) {
1256                 if (cachelist[i].f != NULL &&
1257                     FD_ISSET(fileno(cachelist[i].f), readfds)) {
1258                         cnt++;
1259                         cachelist[i].cache_handle(cachelist[i].f);
1260                         FD_CLR(fileno(cachelist[i].f), readfds);
1261                 }
1262         }
1263         return cnt;
1264 }
1265
1266
1267 /*
1268  * Give IP->domain and domain+path->options to kernel
1269  * % echo nfsd $IP  $[now+DEFAULT_TTL] $domain > /proc/net/rpc/auth.unix.ip/channel
1270  * % echo $domain $path $[now+DEFAULT_TTL] $options $anonuid $anongid $fsid > /proc/net/rpc/nfsd.export/channel
1271  */
1272
1273 static int cache_export_ent(char *domain, struct exportent *exp, char *path)
1274 {
1275         int err;
1276         FILE *f = fopen("/proc/net/rpc/nfsd.export/channel", "w");
1277         if (!f)
1278                 return -1;
1279
1280         err = dump_to_cache(f, domain, exp->e_path, exp);
1281         if (err) {
1282                 xlog(L_WARNING,
1283                      "Cannot export %s, possibly unsupported filesystem or"
1284                      " fsid= required", exp->e_path);
1285         }
1286
1287         while (err == 0 && (exp->e_flags & NFSEXP_CROSSMOUNT) && path) {
1288                 /* really an 'if', but we can break out of
1289                  * a 'while' more easily */
1290                 /* Look along 'path' for other filesystems
1291                  * and export them with the same options
1292                  */
1293                 struct stat stb;
1294                 size_t l = strlen(exp->e_path);
1295                 __dev_t dev;
1296
1297                 if (strlen(path) <= l || path[l] != '/' ||
1298                     strncmp(exp->e_path, path, l) != 0)
1299                         break;
1300                 if (stat(exp->e_path, &stb) != 0)
1301                         break;
1302                 dev = stb.st_dev;
1303                 while(path[l] == '/') {
1304                         char c;
1305                         /* errors for submount should fail whole filesystem */
1306                         int err2;
1307
1308                         l++;
1309                         while (path[l] != '/' && path[l])
1310                                 l++;
1311                         c = path[l];
1312                         path[l] = 0;
1313                         err2 = lstat(path, &stb);
1314                         path[l] = c;
1315                         if (err2 < 0)
1316                                 break;
1317                         if (stb.st_dev == dev)
1318                                 continue;
1319                         dev = stb.st_dev;
1320                         path[l] = 0;
1321                         dump_to_cache(f, domain, path, exp);
1322                         path[l] = c;
1323                 }
1324                 break;
1325         }
1326
1327         fclose(f);
1328         return err;
1329 }
1330
1331 /**
1332  * cache_export - Inform kernel of a new nfs_export
1333  * @exp: target nfs_export
1334  * @path: NUL-terminated C string containing export path
1335  */
1336 int cache_export(nfs_export *exp, char *path)
1337 {
1338         char buf[INET6_ADDRSTRLEN];
1339         int err;
1340         FILE *f;
1341
1342         f = fopen("/proc/net/rpc/auth.unix.ip/channel", "w");
1343         if (!f)
1344                 return -1;
1345
1346
1347         qword_print(f, "nfsd");
1348         qword_print(f,
1349                 host_ntop(get_addrlist(exp->m_client, 0), buf, sizeof(buf)));
1350         qword_printtimefrom(f, exp->m_export.e_ttl);
1351         qword_print(f, exp->m_client->m_hostname);
1352         err = qword_eol(f);
1353
1354         fclose(f);
1355
1356         err = cache_export_ent(exp->m_client->m_hostname, &exp->m_export, path)
1357                 || err;
1358         return err;
1359 }
1360
1361 /**
1362  * cache_get_filehandle - given an nfs_export, get its root filehandle
1363  * @exp: target nfs_export
1364  * @len: length of requested file handle
1365  * @p: NUL-terminated C string containing export path
1366  *
1367  * Returns pointer to NFS file handle of root directory of export
1368  *
1369  * {
1370  *   echo $domain $path $length
1371  *   read filehandle <&0
1372  * } <> /proc/fs/nfsd/filehandle
1373  */
1374 struct nfs_fh_len *
1375 cache_get_filehandle(nfs_export *exp, int len, char *p)
1376 {
1377         FILE *f = fopen("/proc/fs/nfsd/filehandle", "r+");
1378         char buf[200];
1379         char *bp = buf;
1380         int failed;
1381         static struct nfs_fh_len fh;
1382
1383         if (!f)
1384                 f = fopen("/proc/fs/nfs/filehandle", "r+");
1385         if (!f)
1386                 return NULL;
1387
1388         qword_print(f, exp->m_client->m_hostname);
1389         qword_print(f, p);
1390         qword_printint(f, len);
1391         failed = qword_eol(f);
1392
1393         if (!failed)
1394                 failed = (fgets(buf, sizeof(buf), f) == NULL);
1395         fclose(f);
1396         if (failed)
1397                 return NULL;
1398         memset(fh.fh_handle, 0, sizeof(fh.fh_handle));
1399         fh.fh_size = qword_get(&bp, (char *)fh.fh_handle, NFS3_FHSIZE);
1400         return &fh;
1401 }