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 /* True iff e1 is a child of e2 and e2 has crossmnt set: */
 347 static bool subexport(struct exportent *e1, struct exportent *e2)
 348 {
 349         char *p1 = e1->e_path, *p2 = e2->e_path;
 350         size_t l2 = strlen(p2);
 351
 352         return e2->e_flags & NFSEXP_CROSSMOUNT
 353                && strncmp(p1, p2, l2) == 0
 354                && p1[l2] == '/';
 355 }
 356
 357 struct parsed_fsid {
 358         int fsidtype;
 359         /* We could use a union for this, but it would be more
 360          * complicated; why bother? */
 361         unsigned int inode;
 362         unsigned int minor;
 363         unsigned int major;
 364         unsigned int fsidnum;
 365         size_t uuidlen;
 366         char *fhuuid;
 367 };
 368
 369 static int parse_fsid(int fsidtype, int fsidlen, char *fsid,
 370                 struct parsed_fsid *parsed)
 371 {
 372         unsigned int dev;
 373         unsigned long long inode64;
 374
 375         memset(parsed, 0, sizeof(*parsed));
 376         parsed->fsidtype = fsidtype;
 377         switch(fsidtype) {
 378         case FSID_DEV: /* 4 bytes: 2 major, 2 minor, 4 inode */
 379                 if (fsidlen != 8)
 380                         return -1;
 381                 memcpy(&dev, fsid, 4);
 382                 memcpy(&parsed->inode, fsid+4, 4);
 383                 parsed->major = ntohl(dev)>>16;
 384                 parsed->minor = ntohl(dev) & 0xFFFF;
 385                 break;
 386
 387         case FSID_NUM: /* 4 bytes - fsid */
 388                 if (fsidlen != 4)
 389                         return -1;
 390                 memcpy(&parsed->fsidnum, fsid, 4);
 391                 break;
 392
 393         case FSID_MAJOR_MINOR: /* 12 bytes: 4 major, 4 minor, 4 inode
 394                  * This format is never actually used but was
 395                  * an historical accident
 396                  */
 397                 if (fsidlen != 12)
 398                         return -1;
 399                 memcpy(&dev, fsid, 4);
 400                 parsed->major = ntohl(dev);
 401                 memcpy(&dev, fsid+4, 4);
 402                 parsed->minor = ntohl(dev);
 403                 memcpy(&parsed->inode, fsid+8, 4);
 404                 break;
 405
 406         case FSID_ENCODE_DEV: /* 8 bytes: 4 byte packed device number, 4 inode */
 407                 /* This is *host* endian, not net-byte-order, because
 408                  * no-one outside this host has any business interpreting it
 409                  */
 410                 if (fsidlen != 8)
 411                         return -1;
 412                 memcpy(&dev, fsid, 4);
 413                 memcpy(&parsed->inode, fsid+4, 4);
 414                 parsed->major = (dev & 0xfff00) >> 8;
 415                 parsed->minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
 416                 break;
 417
 418         case FSID_UUID4_INUM: /* 4 byte inode number and 4 byte uuid */
 419                 if (fsidlen != 8)
 420                         return -1;
 421                 memcpy(&parsed->inode, fsid, 4);
 422                 parsed->uuidlen = 4;
 423                 parsed->fhuuid = fsid+4;
 424                 break;
 425         case FSID_UUID8: /* 8 byte uuid */
 426                 if (fsidlen != 8)
 427                         return -1;
 428                 parsed->uuidlen = 8;
 429                 parsed->fhuuid = fsid;
 430                 break;
 431         case FSID_UUID16: /* 16 byte uuid */
 432                 if (fsidlen != 16)
 433                         return -1;
 434                 parsed->uuidlen = 16;
 435                 parsed->fhuuid = fsid;
 436                 break;
 437         case FSID_UUID16_INUM: /* 8 byte inode number and 16 byte uuid */
 438                 if (fsidlen != 24)
 439                         return -1;
 440                 memcpy(&inode64, fsid, 8);
 441                 parsed->inode = inode64;
 442                 parsed->uuidlen = 16;
 443                 parsed->fhuuid = fsid+8;
 444                 break;
 445         }
 446         return 0;
 447 }
 448
 449 static bool match_fsid(struct parsed_fsid *parsed, nfs_export *exp, char *path)
 450 {
 451         struct stat stb;
 452         int type;
 453         char u[16];
 454
 455         if (stat(path, &stb) != 0)
 456                 return false;
 457         if (!S_ISDIR(stb.st_mode) && !S_ISREG(stb.st_mode))
 458                 return false;
 459
 460         switch (parsed->fsidtype) {
 461         case FSID_DEV:
 462         case FSID_MAJOR_MINOR:
 463         case FSID_ENCODE_DEV:
 464                 if (stb.st_ino != parsed->inode)
 465                         return false;
 466                 if (parsed->major != major(stb.st_dev) ||
 467                     parsed->minor != minor(stb.st_dev))
 468                         return false;
 469                 return true;
 470         case FSID_NUM:
 471                 if (((exp->m_export.e_flags & NFSEXP_FSID) == 0 ||
 472                      exp->m_export.e_fsid != parsed->fsidnum))
 473                         return false;
 474                 return true;
 475         case FSID_UUID4_INUM:
 476         case FSID_UUID16_INUM:
 477                 if (stb.st_ino != parsed->inode)
 478                         return false;
 479                 goto check_uuid;
 480         case FSID_UUID8:
 481         case FSID_UUID16:
 482                 if (!is_mountpoint(path))
 483                         return false;
 484         check_uuid:
 485                 if (exp->m_export.e_uuid)
 486                         get_uuid(exp->m_export.e_uuid, parsed->uuidlen, u);
 487                 else
 488                         for (type = 0;
 489                              uuid_by_path(path, type, parsed->uuidlen, u);
 490                              type++)
 491                                 if (memcmp(u, parsed->fhuuid, parsed->uuidlen) == 0)
 492                                         return true;
 493
 494                 if (memcmp(u, parsed->fhuuid, parsed->uuidlen) != 0)
 495                         return false;
 496                 return true;
 497         }
 498         /* Well, unreachable, actually: */
 499         return false;
 500 }
 501
 502 static struct addrinfo *lookup_client_addr(char *dom)
 503 {
 504         struct addrinfo *ret;
 505         struct addrinfo *tmp;
 506
 507         dom++; /* skip initial "$" */
 508
 509         tmp = host_pton(dom);
 510         if (tmp == NULL)
 511                 return NULL;
 512         ret = client_resolve(tmp->ai_addr);
 513         freeaddrinfo(tmp);
 514         return ret;
 515 }
 516
 517 static void nfsd_fh(FILE *f)
 518 {
 519         /* request are:
 520          *  domain fsidtype fsid
 521          * interpret fsid, find export point and options, and write:
 522          *  domain fsidtype fsid expiry path
 523          */
 524         char *cp;
 525         char *dom;
 526         int fsidtype;
 527         int fsidlen;
 528         char fsid[32];
 529         struct parsed_fsid parsed;
 530         struct exportent *found = NULL;
 531         struct addrinfo *ai = NULL;
 532         char *found_path = NULL;
 533         nfs_export *exp;
 534         int i;
 535         int dev_missing = 0;
 536
 537         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 538                 return;
 539
 540         xlog(D_CALL, "nfsd_fh: inbuf '%s'", lbuf);
 541
 542         cp = lbuf;
 543
 544         dom = malloc(strlen(cp));
 545         if (dom == NULL)
 546                 return;
 547         if (qword_get(&cp, dom, strlen(cp)) <= 0)
 548                 goto out;
 549         if (qword_get_int(&cp, &fsidtype) != 0)
 550                 goto out;
 551         if (fsidtype < 0 || fsidtype > 7)
 552                 goto out; /* unknown type */
 553         if ((fsidlen = qword_get(&cp, fsid, 32)) <= 0)
 554                 goto out;
 555         if (parse_fsid(fsidtype, fsidlen, fsid, &parsed))
 556                 goto out;
 557
 558         auth_reload();
 559
 560         if (is_ipaddr_client(dom)) {
 561                 ai = lookup_client_addr(dom);
 562                 if (!ai)
 563                         goto out;
 564         }
 565
 566         /* Now determine export point for this fsid/domain */
 567         for (i=0 ; i < MCL_MAXTYPES; i++) {
 568                 nfs_export *next_exp;
 569                 for (exp = exportlist[i].p_head; exp; exp = next_exp) {
 570                         char *path;
 571
 572                         if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT) {
 573                                 static nfs_export *prev = NULL;
 574                                 static void *mnt = NULL;
 575
 576                                 if (prev == exp) {
 577                                         /* try a submount */
 578                                         path = next_mnt(&mnt, exp->m_export.e_path);
 579                                         if (!path) {
 580                                                 next_exp = exp->m_next;
 581                                                 prev = NULL;
 582                                                 continue;
 583                                         }
 584                                         next_exp = exp;
 585                                 } else {
 586                                         prev = exp;
 587                                         mnt = NULL;
 588                                         path = exp->m_export.e_path;
 589                                         next_exp = exp;
 590                                 }
 591                         } else {
 592                                 path = exp->m_export.e_path;
 593                                 next_exp = exp->m_next;
 594                         }
 595
 596                         if (!is_ipaddr_client(dom)
 597                                         && !namelist_client_matches(exp, dom))
 598                                 continue;
 599                         if (exp->m_export.e_mountpoint &&
 600                             !is_mountpoint(exp->m_export.e_mountpoint[0]?
 601                                            exp->m_export.e_mountpoint:
 602                                            exp->m_export.e_path))
 603                                 dev_missing ++;
 604
 605                         if (!match_fsid(&parsed, exp, path))
 606                                 continue;
 607                         if (is_ipaddr_client(dom)
 608                                         && !ipaddr_client_matches(exp, ai))
 609                                 continue;
 610                         if (!found || subexport(&exp->m_export, found)) {
 611                                 found = &exp->m_export;
 612                                 free(found_path);
 613                                 found_path = strdup(path);
 614                                 if (found_path == NULL)
 615                                         goto out;
 616                         } else if (strcmp(found->e_path, exp->m_export.e_path) != 0
 617                                    && !subexport(found, &exp->m_export))
 618                         {
 619                                 xlog(L_WARNING, "%s and %s have same filehandle for %s, using first",
 620                                      found_path, path, dom);
 621                         } else {
 622                                 /* same path, if one is V4ROOT, choose the other */
 623                                 if (found->e_flags & NFSEXP_V4ROOT) {
 624                                         found = &exp->m_export;
 625                                         free(found_path);
 626                                         found_path = strdup(path);
 627                                         if (found_path == NULL)
 628                                                 goto out;
 629                                 }
 630                         }
 631                 }
 632         }
 633         if (found &&
 634             found->e_mountpoint &&
 635             !is_mountpoint(found->e_mountpoint[0]?
 636                            found->e_mountpoint:
 637                            found->e_path)) {
 638                 /* Cannot export this yet
 639                  * should log a warning, but need to rate limit
 640                    xlog(L_WARNING, "%s not exported as %d not a mountpoint",
 641                    found->e_path, found->e_mountpoint);
 642                  */
 643                 /* FIXME we need to make sure we re-visit this later */
 644                 goto out;
 645         }
 646         if (!found && dev_missing) {
 647                 /* The missing dev could be what we want, so just be
 648                  * quite rather than returning stale yet
 649                  */
 650                 goto out;
 651         }
 652
 653         if (found)
 654                 if (cache_export_ent(dom, found, found_path) < 0)
 655                         found = 0;
 656
 657         qword_print(f, dom);
 658         qword_printint(f, fsidtype);
 659         qword_printhex(f, fsid, fsidlen);
 660         /* The fsid -> path lookup can be quite expensive as it
 661          * potentially stats and reads lots of devices, and some of those
 662          * might have spun-down.  The Answer is not likely to
 663          * change underneath us, and an 'exportfs -f' can always
 664          * remove this from the kernel, so use a really log
 665          * timeout.  Maybe this should be configurable on the command
 666          * line.
 667          */
 668         qword_printint(f, 0x7fffffff);
 669         if (found)
 670                 qword_print(f, found_path);
 671         qword_eol(f);
 672  out:
 673         if (found_path)
 674                 free(found_path);
 675         freeaddrinfo(ai);
 676         free(dom);
 677         xlog(D_CALL, "nfsd_fh: found %p path %s", found, found ? found->e_path : NULL);
 678         return;
 679 }
 680
 681 static void write_fsloc(FILE *f, struct exportent *ep)
 682 {
 683         struct servers *servers;
 684
 685         if (ep->e_fslocmethod == FSLOC_NONE)
 686                 return;
 687
 688         servers = replicas_lookup(ep->e_fslocmethod, ep->e_fslocdata);
 689         if (!servers)
 690                 return;
 691         qword_print(f, "fsloc");
 692         qword_printint(f, servers->h_num);
 693         if (servers->h_num >= 0) {
 694                 int i;
 695                 for (i=0; i<servers->h_num; i++) {
 696                         qword_print(f, servers->h_mp[i]->h_host);
 697                         qword_print(f, servers->h_mp[i]->h_path);
 698                 }
 699         }
 700         qword_printint(f, servers->h_referral);
 701         release_replicas(servers);
 702 }
 703
 704 static void write_secinfo(FILE *f, struct exportent *ep, int flag_mask)
 705 {
 706         struct sec_entry *p;
 707
 708         for (p = ep->e_secinfo; p->flav; p++)
 709                 ; /* Do nothing */
 710         if (p == ep->e_secinfo) {
 711                 /* There was no sec= option */
 712                 return;
 713         }
 714         qword_print(f, "secinfo");
 715         qword_printint(f, p - ep->e_secinfo);
 716         for (p = ep->e_secinfo; p->flav; p++) {
 717                 qword_printint(f, p->flav->fnum);
 718                 qword_printint(f, p->flags & flag_mask);
 719         }
 720
 721 }
 722
 723 static int dump_to_cache(FILE *f, char *domain, char *path, struct exportent *exp)
 724 {
 725         qword_print(f, domain);
 726         qword_print(f, path);
 727         if (exp) {
 728                 int different_fs = strcmp(path, exp->e_path) != 0;
 729                 int flag_mask = different_fs ? ~NFSEXP_FSID : ~0;
 730
 731                 qword_printtimefrom(f, exp->e_ttl);
 732                 qword_printint(f, exp->e_flags & flag_mask);
 733                 qword_printint(f, exp->e_anonuid);
 734                 qword_printint(f, exp->e_anongid);
 735                 qword_printint(f, exp->e_fsid);
 736                 write_fsloc(f, exp);
 737                 write_secinfo(f, exp, flag_mask);
 738                 if (exp->e_uuid == NULL || different_fs) {
 739                         char u[16];
 740                         if (uuid_by_path(path, 0, 16, u)) {
 741                                 qword_print(f, "uuid");
 742                                 qword_printhex(f, u, 16);
 743                         }
 744                 } else {
 745                         char u[16];
 746                         get_uuid(exp->e_uuid, 16, u);
 747                         qword_print(f, "uuid");
 748                         qword_printhex(f, u, 16);
 749                 }
 750         } else
 751                 qword_printtimefrom(f, DEFAULT_TTL);
 752         return qword_eol(f);
 753 }
 754
 755 static int is_subdirectory(char *child, char *parent)
 756 {
 757         size_t l = strlen(parent);
 758
 759         return strcmp(child, parent) == 0
 760                 || (strncmp(child, parent, l) == 0 && child[l] == '/');
 761 }
 762
 763 static int path_matches(nfs_export *exp, char *path)
 764 {
 765         if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT)
 766                 return is_subdirectory(path, exp->m_export.e_path);
 767         return strcmp(path, exp->m_export.e_path) == 0;
 768 }
 769
 770 static int
 771 export_matches(nfs_export *exp, char *dom, char *path, struct addrinfo *ai)
 772 {
 773         return path_matches(exp, path) && client_matches(exp, dom, ai);
 774 }
 775
 776 static nfs_export *
 777 lookup_export(char *dom, char *path, struct addrinfo *ai)
 778 {
 779         nfs_export *exp;
 780         nfs_export *found = NULL;
 781         int found_type = 0;
 782         int i;
 783
 784         for (i=0 ; i < MCL_MAXTYPES; i++) {
 785                 for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
 786                         if (!export_matches(exp, dom, path, ai))
 787                                 continue;
 788                         if (!found) {
 789                                 found = exp;
 790                                 found_type = i;
 791                                 continue;
 792                         }
 793                         /* Always prefer non-V4ROOT exports */
 794                         if (exp->m_export.e_flags & NFSEXP_V4ROOT)
 795                                 continue;
 796                         if (found->m_export.e_flags & NFSEXP_V4ROOT) {
 797                                 found = exp;
 798                                 found_type = i;
 799                                 continue;
 800                         }
 801
 802                         /* If one is a CROSSMOUNT, then prefer the longest path */
 803                         if (((found->m_export.e_flags & NFSEXP_CROSSMOUNT) ||
 804                              (exp->m_export.e_flags & NFSEXP_CROSSMOUNT)) &&
 805                             strlen(found->m_export.e_path) !=
 806                             strlen(exp->m_export.e_path)) {
 807
 808                                 if (strlen(exp->m_export.e_path) >
 809                                     strlen(found->m_export.e_path)) {
 810                                         found = exp;
 811                                         found_type = i;
 812                                 }
 813                                 continue;
 814
 815                         } else if (found_type == i && found->m_warned == 0) {
 816                                 xlog(L_WARNING, "%s exported to both %s and %s, "
 817                                      "arbitrarily choosing options from first",
 818                                      path, found->m_client->m_hostname, exp->m_client->m_hostname,
 819                                      dom);
 820                                 found->m_warned = 1;
 821                         }
 822                 }
 823         }
 824         return found;
 825 }
 826
 827 #ifdef HAVE_NFS_PLUGIN_H
 828 #include <dlfcn.h>
 829 #include <link.h>
 830 #include <nfs-plugin.h>
 831
 832 /*
 833  * Find the export entry for the parent of "pathname".
 834  * Caller must not free returned exportent.
 835  */
 836 static struct exportent *lookup_parent_export(char *dom,
 837                 const char *pathname, struct addrinfo *ai)
 838 {
 839         char *parent, *slash;
 840         nfs_export *result;
 841
 842         parent = strdup(pathname);
 843         if (parent == NULL) {
 844                 xlog(D_GENERAL, "%s: failed to allocate parent path buffer",
 845                         __func__);
 846                 goto out_default;
 847         }
 848         xlog(D_CALL, "%s: pathname = '%s'", __func__, pathname);
 849
 850 again:
 851         /* shorten pathname by one component */
 852         slash = strrchr(parent, '/');
 853         if (slash == NULL) {
 854                 xlog(D_GENERAL, "%s: no slash found in pathname",
 855                         __func__);
 856                 goto out_default;
 857         }
 858         *slash = '\0';
 859
 860         if (strlen(parent) == 0) {
 861                 result = lookup_export(dom, "/", ai);
 862                 if (result == NULL) {
 863                         xlog(L_ERROR, "%s: no root export found.", __func__);
 864                         goto out_default;
 865                 }
 866                 goto out;
 867         }
 868
 869         result = lookup_export(dom, parent, ai);
 870         if (result == NULL) {
 871                 xlog(D_GENERAL, "%s: lookup_export(%s) found nothing",
 872                         __func__, parent);
 873                 goto again;
 874         }
 875
 876 out:
 877         xlog(D_CALL, "%s: found export for %s", __func__, parent);
 878         free(parent);
 879         return &result->m_export;
 880
 881 out_default:
 882         free(parent);
 883         return mkexportent("*", "/", "insecure");
 884 }
 885
 886 /*
 887  * Walk through a set of FS locations and build an e_fslocdata string.
 888  * Returns true if all went to plan; otherwise, false.
 889  */
 890 static bool locations_to_fslocdata(struct jp_ops *ops,
 891                 nfs_fsloc_set_t locations, char *fslocdata,
 892                 size_t remaining, int *ttl)
 893 {
 894         char *server, *last_path, *rootpath, *ptr;
 895         _Bool seen = false;
 896
 897         last_path = NULL;
 898         rootpath = NULL;
 899         server = NULL;
 900         ptr = fslocdata;
 901         *ttl = 0;
 902
 903         for (;;) {
 904                 enum jp_status status;
 905                 int len;
 906
 907                 status = ops->jp_get_next_location(locations, &server,
 908                                                         &rootpath, ttl);
 909                 if (status == JP_EMPTY)
 910                         break;
 911                 if (status != JP_OK) {
 912                         xlog(D_GENERAL, "%s: failed to parse location: %s",
 913                                 __func__, ops->jp_error(status));
 914                         goto out_false;
 915                 }
 916                 xlog(D_GENERAL, "%s: Location: %s:%s",
 917                         __func__, server, rootpath);
 918
 919                 if (last_path && strcmp(rootpath, last_path) == 0) {
 920                         len = snprintf(ptr, remaining, "+%s", server);
 921                         if (len < 0) {
 922                                 xlog(D_GENERAL, "%s: snprintf: %m", __func__);
 923                                 goto out_false;
 924                         }
 925                         if ((size_t)len >= remaining) {
 926                                 xlog(D_GENERAL, "%s: fslocdata buffer overflow", __func__);
 927                                 goto out_false;
 928                         }
 929                         remaining -= (size_t)len;
 930                         ptr += len;
 931                 } else {
 932                         if (last_path == NULL)
 933                                 len = snprintf(ptr, remaining, "%s@%s",
 934                                                         rootpath, server);
 935                         else
 936                                 len = snprintf(ptr, remaining, ":%s@%s",
 937                                                         rootpath, server);
 938                         if (len < 0) {
 939                                 xlog(D_GENERAL, "%s: snprintf: %m", __func__);
 940                                 goto out_false;
 941                         }
 942                         if ((size_t)len >= remaining) {
 943                                 xlog(D_GENERAL, "%s: fslocdata buffer overflow",
 944                                         __func__);
 945                                 goto out_false;
 946                         }
 947                         remaining -= (size_t)len;
 948                         ptr += len;
 949                         last_path = rootpath;
 950                 }
 951
 952                 seen = true;
 953                 free(rootpath);
 954                 free(server);
 955         }
 956
 957         xlog(D_CALL, "%s: fslocdata='%s', ttl=%d",
 958                 __func__, fslocdata, *ttl);
 959         return seen;
 960
 961 out_false:
 962         free(rootpath);
 963         free(server);
 964         return false;
 965 }
 966
 967 /*
 968  * Duplicate the junction's parent's export options and graft in
 969  * the fslocdata we constructed from the locations list.
 970  */
 971 static struct exportent *create_junction_exportent(struct exportent *parent,
 972                 const char *junction, const char *fslocdata, int ttl)
 973 {
 974         static struct exportent *eep;
 975
 976         eep = (struct exportent *)malloc(sizeof(*eep));
 977         if (eep == NULL)
 978                 goto out_nomem;
 979
 980         dupexportent(eep, parent);
 981         strcpy(eep->e_path, junction);
 982         eep->e_hostname = strdup(parent->e_hostname);
 983         if (eep->e_hostname == NULL) {
 984                 free(eep);
 985                 goto out_nomem;
 986         }
 987         free(eep->e_uuid);
 988         eep->e_uuid = NULL;
 989         eep->e_ttl = (unsigned int)ttl;
 990
 991         free(eep->e_fslocdata);
 992         eep->e_fslocdata = strdup(fslocdata);
 993         if (eep->e_fslocdata == NULL) {
 994                 free(eep->e_hostname);
 995                 free(eep);
 996                 goto out_nomem;
 997         }
 998         eep->e_fslocmethod = FSLOC_REFER;
 999         return eep;
1000
1001 out_nomem:
1002         xlog(L_ERROR, "%s: No memory", __func__);
1003         return NULL;
1004 }
1005
1006 /*
1007  * Walk through the set of FS locations and build an exportent.
1008  * Returns pointer to an exportent if "junction" refers to a junction.
1009  */
1010 static struct exportent *locations_to_export(struct jp_ops *ops,
1011                 nfs_fsloc_set_t locations, const char *junction,
1012                 struct exportent *parent)
1013 {
1014         static char fslocdata[BUFSIZ];
1015         int ttl;
1016
1017         fslocdata[0] = '\0';
1018         if (!locations_to_fslocdata(ops, locations,
1019                                         fslocdata, sizeof(fslocdata), &ttl))
1020                 return NULL;
1021         return create_junction_exportent(parent, junction, fslocdata, ttl);
1022 }
1023
1024 /*
1025  * Retrieve locations information in "junction" and dump it to the
1026  * kernel.  Returns pointer to an exportent if "junction" refers
1027  * to a junction.
1028  */
1029 static struct exportent *invoke_junction_ops(void *handle, char *dom,
1030                 const char *junction, struct addrinfo *ai)
1031 {
1032         struct exportent *parent, *exp = NULL;
1033         nfs_fsloc_set_t locations;
1034         enum jp_status status;
1035         struct jp_ops *ops;
1036         char *error;
1037
1038         ops = (struct jp_ops *)dlsym(handle, "nfs_junction_ops");
1039         error = dlerror();
1040         if (error != NULL) {
1041                 xlog(D_GENERAL, "%s: dlsym(jp_junction_ops): %s",
1042                         __func__, error);
1043                 return NULL;
1044         }
1045         if (ops->jp_api_version != JP_API_VERSION) {
1046                 xlog(D_GENERAL, "%s: unrecognized junction API version: %u",
1047                         __func__, ops->jp_api_version);
1048                 return NULL;
1049         }
1050
1051         status = ops->jp_init(false);
1052         if (status != JP_OK) {
1053                 xlog(D_GENERAL, "%s: failed to resolve %s: %s",
1054                         __func__, junction, ops->jp_error(status));
1055                 return NULL;
1056         }
1057
1058         status = ops->jp_get_locations(junction, &locations);
1059         switch (status) {
1060         case JP_OK:
1061                 break;
1062         case JP_NOTJUNCTION:
1063                 xlog(D_GENERAL, "%s: %s is not a junction",
1064                         __func__, junction);
1065                 goto out;
1066         default:
1067                 xlog(L_WARNING, "Dangling junction %s: %s",
1068                         junction, ops->jp_error(status));
1069                 goto out;
1070         }
1071
1072         parent = lookup_parent_export(dom, junction, ai);
1073         if (parent == NULL)
1074                 goto out;
1075
1076         exp = locations_to_export(ops, locations, junction, parent);
1077
1078         ops->jp_put_locations(locations);
1079
1080 out:
1081         ops->jp_done();
1082         return exp;
1083 }
1084
1085 /*
1086  * Load the junction plug-in, then try to resolve "pathname".
1087  * Returns pointer to an initialized exportent if "junction"
1088  * refers to a junction, or NULL if not.
1089  */
1090 static struct exportent *lookup_junction(char *dom, const char *pathname,
1091                 struct addrinfo *ai)
1092 {
1093         struct exportent *exp;
1094         struct link_map *map;
1095         void *handle;
1096
1097         handle = dlopen("libnfsjunct.so", RTLD_NOW);
1098         if (handle == NULL) {
1099                 xlog(D_GENERAL, "%s: dlopen: %s", __func__, dlerror());
1100                 return NULL;
1101         }
1102
1103         if (dlinfo(handle, RTLD_DI_LINKMAP, &map) == 0)
1104                 xlog(D_GENERAL, "%s: loaded plug-in %s",
1105                         __func__, map->l_name);
1106
1107         (void)dlerror();        /* Clear any error */
1108
1109         exp = invoke_junction_ops(handle, dom, pathname, ai);
1110
1111         /* We could leave it loaded to make junction resolution
1112          * faster next time.  However, if we want to replace the
1113          * library, that would require restarting mountd. */
1114         (void)dlclose(handle);
1115         return exp;
1116 }
1117
1118 static void lookup_nonexport(FILE *f, char *dom, char *path,
1119                 struct addrinfo *ai)
1120 {
1121         struct exportent *eep;
1122
1123         eep = lookup_junction(dom, path, ai);
1124         dump_to_cache(f, dom, path, eep);
1125         if (eep == NULL)
1126                 return;
1127         exportent_release(eep);
1128         free(eep);
1129 }
1130 #else   /* !HAVE_NFS_PLUGIN_H */
1131 static void lookup_nonexport(FILE *f, char *dom, char *path,
1132                 struct addrinfo *UNUSED(ai))
1133 {
1134         dump_to_cache(f, dom, path, NULL);
1135 }
1136 #endif  /* !HAVE_NFS_PLUGIN_H */
1137
1138 static void nfsd_export(FILE *f)
1139 {
1140         /* requests are:
1141          *  domain path
1142          * determine export options and return:
1143          *  domain path expiry flags anonuid anongid fsid
1144          */
1145
1146         char *cp;
1147         char *dom, *path;
1148         nfs_export *found = NULL;
1149         struct addrinfo *ai = NULL;
1150
1151         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
1152                 return;
1153
1154         xlog(D_CALL, "nfsd_export: inbuf '%s'", lbuf);
1155
1156         cp = lbuf;
1157         dom = malloc(strlen(cp));
1158         path = malloc(strlen(cp));
1159
1160         if (!dom || !path)
1161                 goto out;
1162
1163         if (qword_get(&cp, dom, strlen(lbuf)) <= 0)
1164                 goto out;
1165         if (qword_get(&cp, path, strlen(lbuf)) <= 0)
1166                 goto out;
1167
1168         auth_reload();
1169
1170         if (is_ipaddr_client(dom)) {
1171                 ai = lookup_client_addr(dom);
1172                 if (!ai)
1173                         goto out;
1174         }
1175
1176         found = lookup_export(dom, path, ai);
1177
1178         if (found) {
1179                 if (dump_to_cache(f, dom, path, &found->m_export) < 0) {
1180                         xlog(L_WARNING,
1181                              "Cannot export %s, possibly unsupported filesystem"
1182                              " or fsid= required", path);
1183                         dump_to_cache(f, dom, path, NULL);
1184                 }
1185         } else
1186                 lookup_nonexport(f, dom, path, ai);
1187
1188  out:
1189         xlog(D_CALL, "nfsd_export: found %p path %s", found, path ? path : NULL);
1190         if (dom) free(dom);
1191         if (path) free(path);
1192         freeaddrinfo(ai);
1193 }
1194
1195
1196 struct {
1197         char *cache_name;
1198         void (*cache_handle)(FILE *f);
1199         FILE *f;
1200         char vbuf[RPC_CHAN_BUF_SIZE];
1201 } cachelist[] = {
1202         { "auth.unix.ip", auth_unix_ip, NULL, ""},
1203         { "auth.unix.gid", auth_unix_gid, NULL, ""},
1204         { "nfsd.export", nfsd_export, NULL, ""},
1205         { "nfsd.fh", nfsd_fh, NULL, ""},
1206         { NULL, NULL, NULL, ""}
1207 };
1208
1209 extern int manage_gids;
1210
1211 /**
1212  * cache_open - prepare communications channels with kernel RPC caches
1213  *
1214  */
1215 void cache_open(void)
1216 {
1217         int i;
1218         for (i=0; cachelist[i].cache_name; i++ ) {
1219                 char path[100];
1220                 if (!manage_gids && cachelist[i].cache_handle == auth_unix_gid)
1221                         continue;
1222                 sprintf(path, "/proc/net/rpc/%s/channel", cachelist[i].cache_name);
1223                 cachelist[i].f = fopen(path, "r+");
1224                 if (cachelist[i].f != NULL) {
1225                         setvbuf(cachelist[i].f, cachelist[i].vbuf, _IOLBF,
1226                                 RPC_CHAN_BUF_SIZE);
1227                 }
1228         }
1229 }
1230
1231 /**
1232  * cache_set_fds - prepare cache file descriptors for one iteration of the service loop
1233  * @fdset: pointer to fd_set to prepare
1234  */
1235 void cache_set_fds(fd_set *fdset)
1236 {
1237         int i;
1238         for (i=0; cachelist[i].cache_name; i++) {
1239                 if (cachelist[i].f)
1240                         FD_SET(fileno(cachelist[i].f), fdset);
1241         }
1242 }
1243
1244 /**
1245  * cache_process_req - process any active cache file descriptors during service loop iteration
1246  * @fdset: pointer to fd_set to examine for activity
1247  */
1248 int cache_process_req(fd_set *readfds)
1249 {
1250         int i;
1251         int cnt = 0;
1252         for (i=0; cachelist[i].cache_name; i++) {
1253                 if (cachelist[i].f != NULL &&
1254                     FD_ISSET(fileno(cachelist[i].f), readfds)) {
1255                         cnt++;
1256                         cachelist[i].cache_handle(cachelist[i].f);
1257                         FD_CLR(fileno(cachelist[i].f), readfds);
1258                 }
1259         }
1260         return cnt;
1261 }
1262
1263
1264 /*
1265  * Give IP->domain and domain+path->options to kernel
1266  * % echo nfsd $IP  $[now+DEFAULT_TTL] $domain > /proc/net/rpc/auth.unix.ip/channel
1267  * % echo $domain $path $[now+DEFAULT_TTL] $options $anonuid $anongid $fsid > /proc/net/rpc/nfsd.export/channel
1268  */
1269
1270 static int cache_export_ent(char *domain, struct exportent *exp, char *path)
1271 {
1272         int err;
1273         FILE *f = fopen("/proc/net/rpc/nfsd.export/channel", "w");
1274         if (!f)
1275                 return -1;
1276
1277         err = dump_to_cache(f, domain, exp->e_path, exp);
1278         if (err) {
1279                 xlog(L_WARNING,
1280                      "Cannot export %s, possibly unsupported filesystem or"
1281                      " fsid= required", exp->e_path);
1282         }
1283
1284         while (err == 0 && (exp->e_flags & NFSEXP_CROSSMOUNT) && path) {
1285                 /* really an 'if', but we can break out of
1286                  * a 'while' more easily */
1287                 /* Look along 'path' for other filesystems
1288                  * and export them with the same options
1289                  */
1290                 struct stat stb;
1291                 size_t l = strlen(exp->e_path);
1292                 __dev_t dev;
1293
1294                 if (strlen(path) <= l || path[l] != '/' ||
1295                     strncmp(exp->e_path, path, l) != 0)
1296                         break;
1297                 if (stat(exp->e_path, &stb) != 0)
1298                         break;
1299                 dev = stb.st_dev;
1300                 while(path[l] == '/') {
1301                         char c;
1302                         /* errors for submount should fail whole filesystem */
1303                         int err2;
1304
1305                         l++;
1306                         while (path[l] != '/' && path[l])
1307                                 l++;
1308                         c = path[l];
1309                         path[l] = 0;
1310                         err2 = lstat(path, &stb);
1311                         path[l] = c;
1312                         if (err2 < 0)
1313                                 break;
1314                         if (stb.st_dev == dev)
1315                                 continue;
1316                         dev = stb.st_dev;
1317                         path[l] = 0;
1318                         dump_to_cache(f, domain, path, exp);
1319                         path[l] = c;
1320                 }
1321                 break;
1322         }
1323
1324         fclose(f);
1325         return err;
1326 }
1327
1328 /**
1329  * cache_export - Inform kernel of a new nfs_export
1330  * @exp: target nfs_export
1331  * @path: NUL-terminated C string containing export path
1332  */
1333 int cache_export(nfs_export *exp, char *path)
1334 {
1335         char buf[INET6_ADDRSTRLEN];
1336         int err;
1337         FILE *f;
1338
1339         f = fopen("/proc/net/rpc/auth.unix.ip/channel", "w");
1340         if (!f)
1341                 return -1;
1342
1343
1344         qword_print(f, "nfsd");
1345         qword_print(f,
1346                 host_ntop(get_addrlist(exp->m_client, 0), buf, sizeof(buf)));
1347         qword_printtimefrom(f, exp->m_export.e_ttl);
1348         qword_print(f, exp->m_client->m_hostname);
1349         err = qword_eol(f);
1350
1351         fclose(f);
1352
1353         err = cache_export_ent(exp->m_client->m_hostname, &exp->m_export, path)
1354                 || err;
1355         return err;
1356 }
1357
1358 /**
1359  * cache_get_filehandle - given an nfs_export, get its root filehandle
1360  * @exp: target nfs_export
1361  * @len: length of requested file handle
1362  * @p: NUL-terminated C string containing export path
1363  *
1364  * Returns pointer to NFS file handle of root directory of export
1365  *
1366  * {
1367  *   echo $domain $path $length
1368  *   read filehandle <&0
1369  * } <> /proc/fs/nfsd/filehandle
1370  */
1371 struct nfs_fh_len *
1372 cache_get_filehandle(nfs_export *exp, int len, char *p)
1373 {
1374         FILE *f = fopen("/proc/fs/nfsd/filehandle", "r+");
1375         char buf[200];
1376         char *bp = buf;
1377         int failed;
1378         static struct nfs_fh_len fh;
1379
1380         if (!f)
1381                 f = fopen("/proc/fs/nfs/filehandle", "r+");
1382         if (!f)
1383                 return NULL;
1384
1385         qword_print(f, exp->m_client->m_hostname);
1386         qword_print(f, p);
1387         qword_printint(f, len);
1388         failed = qword_eol(f);
1389
1390         if (!failed)
1391                 failed = (fgets(buf, sizeof(buf), f) == NULL);
1392         fclose(f);
1393         if (failed)
1394                 return NULL;
1395         memset(fh.fh_handle, 0, sizeof(fh.fh_handle));
1396         fh.fh_size = qword_get(&bp, (char *)fh.fh_handle, NFS3_FHSIZE);
1397         return &fh;
1398 }