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