utils/mountd/cache.c

   1
   2 /*
   3  * Handle communication with knfsd internal cache
   4  *
   5  * We open /proc/net/rpc/{auth.unix.ip,nfsd.export,nfsd.fh}/channel
   6  * and listen for requests (using my_svc_run)
   7  *
   8  */
   9
  10 #ifdef HAVE_CONFIG_H
  11 #include <config.h>
  12 #endif
  13
  14 #include <sys/types.h>
  15 #include <sys/select.h>
  16 #include <sys/stat.h>
  17 #include <sys/vfs.h>
  18 #include <time.h>
  19 #include <netinet/in.h>
  20 #include <arpa/inet.h>
  21 #include <unistd.h>
  22 #include <fcntl.h>
  23 #include <errno.h>
  24 #include <ctype.h>
  25 #include <pwd.h>
  26 #include <grp.h>
  27 #include <mntent.h>
  28 #include "misc.h"
  29 #include "nfslib.h"
  30 #include "exportfs.h"
  31 #include "mountd.h"
  32 #include "fsloc.h"
  33 #include "pseudoflavors.h"
  34
  35 #ifdef USE_BLKID
  36 #include "blkid/blkid.h"
  37 #endif
  38
  39 /*
  40  * Invoked by RPC service loop
  41  */
  42 void    cache_set_fds(fd_set *fdset);
  43 int     cache_process_req(fd_set *readfds);
  44
  45 enum nfsd_fsid {
  46         FSID_DEV = 0,
  47         FSID_NUM,
  48         FSID_MAJOR_MINOR,
  49         FSID_ENCODE_DEV,
  50         FSID_UUID4_INUM,
  51         FSID_UUID8,
  52         FSID_UUID16,
  53         FSID_UUID16_INUM,
  54 };
  55
  56 /*
  57  * Support routines for text-based upcalls.
  58  * Fields are separated by spaces.
  59  * Fields are either mangled to quote space tab newline slosh with slosh
  60  * or a hexified with a leading \x
  61  * Record is terminated with newline.
  62  *
  63  */
  64 static int cache_export_ent(char *domain, struct exportent *exp, char *p);
  65
  66 #define INITIAL_MANAGED_GROUPS 100
  67
  68 char *lbuf  = NULL;
  69 int lbuflen = 0;
  70 extern int use_ipaddr;
  71
  72 static void auth_unix_ip(FILE *f)
  73 {
  74         /* requests are
  75          *  class IP-ADDR
  76          * Ignore if class != "nfsd"
  77          * Otherwise find domainname and write back:
  78          *
  79          *  "nfsd" IP-ADDR expiry domainname
  80          */
  81         char *cp;
  82         char class[20];
  83         char ipaddr[INET6_ADDRSTRLEN];
  84         char *client = NULL;
  85         struct addrinfo *tmp = NULL;
  86         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
  87                 return;
  88
  89         xlog(D_CALL, "auth_unix_ip: inbuf '%s'", lbuf);
  90
  91         cp = lbuf;
  92
  93         if (qword_get(&cp, class, 20) <= 0 ||
  94             strcmp(class, "nfsd") != 0)
  95                 return;
  96
  97         if (qword_get(&cp, ipaddr, sizeof(ipaddr)) <= 0)
  98                 return;
  99
 100         tmp = host_pton(ipaddr);
 101         if (tmp == NULL)
 102                 return;
 103
 104         auth_reload();
 105
 106         /* addr is a valid, interesting address, find the domain name... */
 107         if (!use_ipaddr) {
 108                 struct addrinfo *ai = NULL;
 109
 110                 ai = client_resolve(tmp->ai_addr);
 111                 if (ai) {
 112                         client = client_compose(ai);
 113                         freeaddrinfo(ai);
 114                 }
 115         }
 116         qword_print(f, "nfsd");
 117         qword_print(f, ipaddr);
 118         qword_printtimefrom(f, DEFAULT_TTL);
 119         if (use_ipaddr)
 120                 qword_print(f, ipaddr);
 121         else if (client)
 122                 qword_print(f, *client?client:"DEFAULT");
 123         qword_eol(f);
 124         xlog(D_CALL, "auth_unix_ip: client %p '%s'", client, client?client: "DEFAULT");
 125
 126         free(client);
 127         freeaddrinfo(tmp);
 128
 129 }
 130
 131 static void auth_unix_gid(FILE *f)
 132 {
 133         /* Request are
 134          *  uid
 135          * reply is
 136          *  uid expiry count list of group ids
 137          */
 138         uid_t uid;
 139         struct passwd *pw;
 140         static gid_t *groups = NULL;
 141         static int groups_len = 0;
 142         gid_t *more_groups;
 143         int ngroups;
 144         int rv, i;
 145         char *cp;
 146
 147         if (groups_len == 0) {
 148                 groups = malloc(sizeof(gid_t) * INITIAL_MANAGED_GROUPS);
 149                 if (!groups)
 150                         return;
 151
 152                 groups_len = INITIAL_MANAGED_GROUPS;
 153         }
 154
 155         ngroups = groups_len;
 156
 157         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 158                 return;
 159
 160         cp = lbuf;
 161         if (qword_get_uint(&cp, &uid) != 0)
 162                 return;
 163
 164         pw = getpwuid(uid);
 165         if (!pw)
 166                 rv = -1;
 167         else {
 168                 rv = getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups);
 169                 if (rv == -1 && ngroups >= groups_len) {
 170                         more_groups = realloc(groups, sizeof(gid_t)*ngroups);
 171                         if (!more_groups)
 172                                 rv = -1;
 173                         else {
 174                                 groups = more_groups;
 175                                 groups_len = ngroups;
 176                                 rv = getgrouplist(pw->pw_name, pw->pw_gid,
 177                                                   groups, &ngroups);
 178                         }
 179                 }
 180         }
 181         qword_printuint(f, uid);
 182         qword_printtimefrom(f, DEFAULT_TTL);
 183         if (rv >= 0) {
 184                 qword_printuint(f, ngroups);
 185                 for (i=0; i<ngroups; i++)
 186                         qword_printuint(f, groups[i]);
 187         } else
 188                 qword_printuint(f, 0);
 189         qword_eol(f);
 190 }
 191
 192 #if USE_BLKID
 193 static const char *get_uuid_blkdev(char *path)
 194 {
 195         /* We set *safe if we know that we need the
 196          * fsid from statfs too.
 197          */
 198         static blkid_cache cache = NULL;
 199         struct stat stb;
 200         char *devname;
 201         blkid_tag_iterate iter;
 202         blkid_dev dev;
 203         const char *type;
 204         const char *val, *uuid = NULL;
 205
 206         if (cache == NULL)
 207                 blkid_get_cache(&cache, NULL);
 208
 209         if (stat(path, &stb) != 0)
 210                 return NULL;
 211         devname = blkid_devno_to_devname(stb.st_dev);
 212         if (!devname)
 213                 return NULL;
 214         dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
 215         free(devname);
 216         if (!dev)
 217                 return NULL;
 218         iter = blkid_tag_iterate_begin(dev);
 219         if (!iter)
 220                 return NULL;
 221         while (blkid_tag_next(iter, &type, &val) == 0) {
 222                 if (strcmp(type, "UUID") == 0)
 223                         uuid = val;
 224                 if (strcmp(type, "TYPE") == 0 &&
 225                     strcmp(val, "btrfs") == 0) {
 226                         uuid = NULL;
 227                         break;
 228                 }
 229         }
 230         blkid_tag_iterate_end(iter);
 231         return uuid;
 232 }
 233 #else
 234 #define get_uuid_blkdev(path) (NULL)
 235 #endif
 236
 237 static int get_uuid(const char *val, size_t uuidlen, char *u)
 238 {
 239         /* extract hex digits from uuidstr and compose a uuid
 240          * of the given length (max 16), xoring bytes to make
 241          * a smaller uuid.
 242          */
 243         size_t i = 0;
 244
 245         memset(u, 0, uuidlen);
 246         for ( ; *val ; val++) {
 247                 int c = *val;
 248                 if (!isxdigit(c))
 249                         continue;
 250                 if (isalpha(c)) {
 251                         if (isupper(c))
 252                                 c = c - 'A' + 10;
 253                         else
 254                                 c = c - 'a' + 10;
 255                 } else
 256                         c = c - '0' + 0;
 257                 if ((i&1) == 0)
 258                         c <<= 4;
 259                 u[i/2] ^= (char)c;
 260                 i++;
 261                 if (i == uuidlen*2)
 262                         i = 0;
 263         }
 264         return 1;
 265 }
 266
 267 static int uuid_by_path(char *path, int type, size_t uuidlen, char *uuid)
 268 {
 269         /* get a uuid for the filesystem found at 'path'.
 270          * There are several possible ways of generating the
 271          * uuids (types).
 272          * Type 0 is used for new filehandles, while other types
 273          * may be used to interpret old filehandle - to ensure smooth
 274          * forward migration.
 275          * We return 1 if a uuid was found (and it might be worth
 276          * trying the next type) or 0 if no more uuid types can be
 277          * extracted.
 278          */
 279
 280         /* Possible sources of uuid are
 281          * - blkid uuid
 282          * - statfs64 uuid
 283          *
 284          * On some filesystems (e.g. vfat) the statfs64 uuid is simply an
 285          * encoding of the device that the filesystem is mounted from, so
 286          * it we be very bad to use that (as device numbers change).  blkid
 287          * must be preferred.
 288          * On other filesystems (e.g. btrfs) the statfs64 uuid contains
 289          * important info that the blkid uuid cannot contain:  This happens
 290          * when multiple subvolumes are exported (they have the same
 291          * blkid uuid but different statfs64 uuids).
 292          * We rely on get_uuid_blkdev *knowing* which is which and not returning
 293          * a uuid for filesystems where the statfs64 uuid is better.
 294          *
 295          */
 296         struct statfs64 st;
 297         char fsid_val[17];
 298         const char *blkid_val;
 299         const char *val;
 300
 301         blkid_val = get_uuid_blkdev(path);
 302
 303         if (statfs64(path, &st) == 0 &&
 304             (st.f_fsid.__val[0] || st.f_fsid.__val[1]))
 305                 snprintf(fsid_val, 17, "%08x%08x",
 306                          st.f_fsid.__val[0], st.f_fsid.__val[1]);
 307         else
 308                 fsid_val[0] = 0;
 309
 310         if (blkid_val && (type--) == 0)
 311                 val = blkid_val;
 312         else if (fsid_val[0] && (type--) == 0)
 313                 val = fsid_val;
 314         else
 315                 return 0;
 316
 317         get_uuid(val, uuidlen, uuid);
 318         return 1;
 319 }
 320
 321 /* Iterate through /etc/mtab, finding mountpoints
 322  * at or below a given path
 323  */
 324 static char *next_mnt(void **v, char *p)
 325 {
 326         FILE *f;
 327         struct mntent *me;
 328         size_t l = strlen(p);
 329         if (*v == NULL) {
 330                 f = setmntent("/etc/mtab", "r");
 331                 *v = f;
 332         } else
 333                 f = *v;
 334         while ((me = getmntent(f)) != NULL &&
 335                (strncmp(me->mnt_dir, p, l) != 0 ||
 336                 me->mnt_dir[l] != '/'))
 337                 ;
 338         if (me == NULL) {
 339                 endmntent(f);
 340                 *v = NULL;
 341                 return NULL;
 342         }
 343         return me->mnt_dir;
 344 }
 345
 346 static int is_subdirectory(char *child, char *parent)
 347 {
 348         size_t l = strlen(parent);
 349
 350         if (strcmp(parent, "/") == 0)
 351                 return 1;
 352
 353         return strcmp(child, parent) == 0
 354                 || (strncmp(child, parent, l) == 0 && child[l] == '/');
 355 }
 356
 357 static int path_matches(nfs_export *exp, char *path)
 358 {
 359         if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT)
 360                 return is_subdirectory(path, exp->m_export.e_path);
 361         return strcmp(path, exp->m_export.e_path) == 0;
 362 }
 363
 364 static int
 365 export_matches(nfs_export *exp, char *dom, char *path, struct addrinfo *ai)
 366 {
 367         return path_matches(exp, path) && client_matches(exp, dom, ai);
 368 }
 369
 370 /* True iff e1 is a child of e2 and e2 has crossmnt set: */
 371 static bool subexport(struct exportent *e1, struct exportent *e2)
 372 {
 373         char *p1 = e1->e_path, *p2 = e2->e_path;
 374         size_t l2 = strlen(p2);
 375
 376         return e2->e_flags & NFSEXP_CROSSMOUNT
 377                 && is_subdirectory(p1, p2);
 378 }
 379
 380 struct parsed_fsid {
 381         int fsidtype;
 382         /* We could use a union for this, but it would be more
 383          * complicated; why bother? */
 384         unsigned int inode;
 385         unsigned int minor;
 386         unsigned int major;
 387         unsigned int fsidnum;
 388         size_t uuidlen;
 389         char *fhuuid;
 390 };
 391
 392 static int parse_fsid(int fsidtype, int fsidlen, char *fsid,
 393                 struct parsed_fsid *parsed)
 394 {
 395         unsigned int dev;
 396         unsigned long long inode64;
 397
 398         memset(parsed, 0, sizeof(*parsed));
 399         parsed->fsidtype = fsidtype;
 400         switch(fsidtype) {
 401         case FSID_DEV: /* 4 bytes: 2 major, 2 minor, 4 inode */
 402                 if (fsidlen != 8)
 403                         return -1;
 404                 memcpy(&dev, fsid, 4);
 405                 memcpy(&parsed->inode, fsid+4, 4);
 406                 parsed->major = ntohl(dev)>>16;
 407                 parsed->minor = ntohl(dev) & 0xFFFF;
 408                 break;
 409
 410         case FSID_NUM: /* 4 bytes - fsid */
 411                 if (fsidlen != 4)
 412                         return -1;
 413                 memcpy(&parsed->fsidnum, fsid, 4);
 414                 break;
 415
 416         case FSID_MAJOR_MINOR: /* 12 bytes: 4 major, 4 minor, 4 inode
 417                  * This format is never actually used but was
 418                  * an historical accident
 419                  */
 420                 if (fsidlen != 12)
 421                         return -1;
 422                 memcpy(&dev, fsid, 4);
 423                 parsed->major = ntohl(dev);
 424                 memcpy(&dev, fsid+4, 4);
 425                 parsed->minor = ntohl(dev);
 426                 memcpy(&parsed->inode, fsid+8, 4);
 427                 break;
 428
 429         case FSID_ENCODE_DEV: /* 8 bytes: 4 byte packed device number, 4 inode */
 430                 /* This is *host* endian, not net-byte-order, because
 431                  * no-one outside this host has any business interpreting it
 432                  */
 433                 if (fsidlen != 8)
 434                         return -1;
 435                 memcpy(&dev, fsid, 4);
 436                 memcpy(&parsed->inode, fsid+4, 4);
 437                 parsed->major = (dev & 0xfff00) >> 8;
 438                 parsed->minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
 439                 break;
 440
 441         case FSID_UUID4_INUM: /* 4 byte inode number and 4 byte uuid */
 442                 if (fsidlen != 8)
 443                         return -1;
 444                 memcpy(&parsed->inode, fsid, 4);
 445                 parsed->uuidlen = 4;
 446                 parsed->fhuuid = fsid+4;
 447                 break;
 448         case FSID_UUID8: /* 8 byte uuid */
 449                 if (fsidlen != 8)
 450                         return -1;
 451                 parsed->uuidlen = 8;
 452                 parsed->fhuuid = fsid;
 453                 break;
 454         case FSID_UUID16: /* 16 byte uuid */
 455                 if (fsidlen != 16)
 456                         return -1;
 457                 parsed->uuidlen = 16;
 458                 parsed->fhuuid = fsid;
 459                 break;
 460         case FSID_UUID16_INUM: /* 8 byte inode number and 16 byte uuid */
 461                 if (fsidlen != 24)
 462                         return -1;
 463                 memcpy(&inode64, fsid, 8);
 464                 parsed->inode = inode64;
 465                 parsed->uuidlen = 16;
 466                 parsed->fhuuid = fsid+8;
 467                 break;
 468         }
 469         return 0;
 470 }
 471
 472 static bool match_fsid(struct parsed_fsid *parsed, nfs_export *exp, char *path)
 473 {
 474         struct stat stb;
 475         int type;
 476         char u[16];
 477
 478         if (stat(path, &stb) != 0)
 479                 return false;
 480         if (!S_ISDIR(stb.st_mode) && !S_ISREG(stb.st_mode))
 481                 return false;
 482
 483         switch (parsed->fsidtype) {
 484         case FSID_DEV:
 485         case FSID_MAJOR_MINOR:
 486         case FSID_ENCODE_DEV:
 487                 if (stb.st_ino != parsed->inode)
 488                         return false;
 489                 if (parsed->major != major(stb.st_dev) ||
 490                     parsed->minor != minor(stb.st_dev))
 491                         return false;
 492                 return true;
 493         case FSID_NUM:
 494                 if (((exp->m_export.e_flags & NFSEXP_FSID) == 0 ||
 495                      exp->m_export.e_fsid != parsed->fsidnum))
 496                         return false;
 497                 return true;
 498         case FSID_UUID4_INUM:
 499         case FSID_UUID16_INUM:
 500                 if (stb.st_ino != parsed->inode)
 501                         return false;
 502                 goto check_uuid;
 503         case FSID_UUID8:
 504         case FSID_UUID16:
 505                 if (!is_mountpoint(path))
 506                         return false;
 507         check_uuid:
 508                 if (exp->m_export.e_uuid)
 509                         get_uuid(exp->m_export.e_uuid, parsed->uuidlen, u);
 510                 else
 511                         for (type = 0;
 512                              uuid_by_path(path, type, parsed->uuidlen, u);
 513                              type++)
 514                                 if (memcmp(u, parsed->fhuuid, parsed->uuidlen) == 0)
 515                                         return true;
 516
 517                 if (memcmp(u, parsed->fhuuid, parsed->uuidlen) != 0)
 518                         return false;
 519                 return true;
 520         }
 521         /* Well, unreachable, actually: */
 522         return false;
 523 }
 524
 525 static struct addrinfo *lookup_client_addr(char *dom)
 526 {
 527         struct addrinfo *ret;
 528         struct addrinfo *tmp;
 529
 530         dom++; /* skip initial "$" */
 531
 532         tmp = host_pton(dom);
 533         if (tmp == NULL)
 534                 return NULL;
 535         ret = client_resolve(tmp->ai_addr);
 536         freeaddrinfo(tmp);
 537         return ret;
 538 }
 539
 540 static void nfsd_fh(FILE *f)
 541 {
 542         /* request are:
 543          *  domain fsidtype fsid
 544          * interpret fsid, find export point and options, and write:
 545          *  domain fsidtype fsid expiry path
 546          */
 547         char *cp;
 548         char *dom;
 549         int fsidtype;
 550         int fsidlen;
 551         char fsid[32];
 552         struct parsed_fsid parsed;
 553         struct exportent *found = NULL;
 554         struct addrinfo *ai = NULL;
 555         char *found_path = NULL;
 556         nfs_export *exp;
 557         int i;
 558         int dev_missing = 0;
 559
 560         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 561                 return;
 562
 563         xlog(D_CALL, "nfsd_fh: inbuf '%s'", lbuf);
 564
 565         cp = lbuf;
 566
 567         dom = malloc(strlen(cp));
 568         if (dom == NULL)
 569                 return;
 570         if (qword_get(&cp, dom, strlen(cp)) <= 0)
 571                 goto out;
 572         if (qword_get_int(&cp, &fsidtype) != 0)
 573                 goto out;
 574         if (fsidtype < 0 || fsidtype > 7)
 575                 goto out; /* unknown type */
 576         if ((fsidlen = qword_get(&cp, fsid, 32)) <= 0)
 577                 goto out;
 578         if (parse_fsid(fsidtype, fsidlen, fsid, &parsed))
 579                 goto out;
 580
 581         auth_reload();
 582
 583         if (is_ipaddr_client(dom)) {
 584                 ai = lookup_client_addr(dom);
 585                 if (!ai)
 586                         goto out;
 587         }
 588
 589         /* Now determine export point for this fsid/domain */
 590         for (i=0 ; i < MCL_MAXTYPES; i++) {
 591                 nfs_export *next_exp;
 592                 for (exp = exportlist[i].p_head; exp; exp = next_exp) {
 593                         char *path;
 594
 595                         if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT) {
 596                                 static nfs_export *prev = NULL;
 597                                 static void *mnt = NULL;
 598
 599                                 if (prev == exp) {
 600                                         /* try a submount */
 601                                         path = next_mnt(&mnt, exp->m_export.e_path);
 602                                         if (!path) {
 603                                                 next_exp = exp->m_next;
 604                                                 prev = NULL;
 605                                                 continue;
 606                                         }
 607                                         next_exp = exp;
 608                                 } else {
 609                                         prev = exp;
 610                                         mnt = NULL;
 611                                         path = exp->m_export.e_path;
 612                                         next_exp = exp;
 613                                 }
 614                         } else {
 615                                 path = exp->m_export.e_path;
 616                                 next_exp = exp->m_next;
 617                         }
 618
 619                         if (!is_ipaddr_client(dom)
 620                                         && !namelist_client_matches(exp, dom))
 621                                 continue;
 622                         if (exp->m_export.e_mountpoint &&
 623                             !is_mountpoint(exp->m_export.e_mountpoint[0]?
 624                                            exp->m_export.e_mountpoint:
 625                                            exp->m_export.e_path))
 626                                 dev_missing ++;
 627
 628                         if (!match_fsid(&parsed, exp, path))
 629                                 continue;
 630                         if (is_ipaddr_client(dom)
 631                                         && !ipaddr_client_matches(exp, ai))
 632                                 continue;
 633                         if (!found || subexport(&exp->m_export, found)) {
 634                                 found = &exp->m_export;
 635                                 free(found_path);
 636                                 found_path = strdup(path);
 637                                 if (found_path == NULL)
 638                                         goto out;
 639                         } else if (strcmp(found->e_path, exp->m_export.e_path) != 0
 640                                    && !subexport(found, &exp->m_export))
 641                         {
 642                                 xlog(L_WARNING, "%s and %s have same filehandle for %s, using first",
 643                                      found_path, path, dom);
 644                         } else {
 645                                 /* same path, if one is V4ROOT, choose the other */
 646                                 if (found->e_flags & NFSEXP_V4ROOT) {
 647                                         found = &exp->m_export;
 648                                         free(found_path);
 649                                         found_path = strdup(path);
 650                                         if (found_path == NULL)
 651                                                 goto out;
 652                                 }
 653                         }
 654                 }
 655         }
 656         if (found &&
 657             found->e_mountpoint &&
 658             !is_mountpoint(found->e_mountpoint[0]?
 659                            found->e_mountpoint:
 660                            found->e_path)) {
 661                 /* Cannot export this yet
 662                  * should log a warning, but need to rate limit
 663                    xlog(L_WARNING, "%s not exported as %d not a mountpoint",
 664                    found->e_path, found->e_mountpoint);
 665                  */
 666                 /* FIXME we need to make sure we re-visit this later */
 667                 goto out;
 668         }
 669         if (!found && dev_missing) {
 670                 /* The missing dev could be what we want, so just be
 671                  * quite rather than returning stale yet
 672                  */
 673                 goto out;
 674         }
 675
 676         if (found)
 677                 if (cache_export_ent(dom, found, found_path) < 0)
 678                         found = 0;
 679
 680         qword_print(f, dom);
 681         qword_printint(f, fsidtype);
 682         qword_printhex(f, fsid, fsidlen);
 683         /* The fsid -> path lookup can be quite expensive as it
 684          * potentially stats and reads lots of devices, and some of those
 685          * might have spun-down.  The Answer is not likely to
 686          * change underneath us, and an 'exportfs -f' can always
 687          * remove this from the kernel, so use a really log
 688          * timeout.  Maybe this should be configurable on the command
 689          * line.
 690          */
 691         qword_printint(f, 0x7fffffff);
 692         if (found)
 693                 qword_print(f, found_path);
 694         qword_eol(f);
 695  out:
 696         if (found_path)
 697                 free(found_path);
 698         freeaddrinfo(ai);
 699         free(dom);
 700         xlog(D_CALL, "nfsd_fh: found %p path %s", found, found ? found->e_path : NULL);
 701         return;
 702 }
 703
 704 static void write_fsloc(FILE *f, struct exportent *ep)
 705 {
 706         struct servers *servers;
 707
 708         if (ep->e_fslocmethod == FSLOC_NONE)
 709                 return;
 710
 711         servers = replicas_lookup(ep->e_fslocmethod, ep->e_fslocdata);
 712         if (!servers)
 713                 return;
 714         qword_print(f, "fsloc");
 715         qword_printint(f, servers->h_num);
 716         if (servers->h_num >= 0) {
 717                 int i;
 718                 for (i=0; i<servers->h_num; i++) {
 719                         qword_print(f, servers->h_mp[i]->h_host);
 720                         qword_print(f, servers->h_mp[i]->h_path);
 721                 }
 722         }
 723         qword_printint(f, servers->h_referral);
 724         release_replicas(servers);
 725 }
 726
 727 static void write_secinfo(FILE *f, struct exportent *ep, int flag_mask)
 728 {
 729         struct sec_entry *p;
 730
 731         for (p = ep->e_secinfo; p->flav; p++)
 732                 ; /* Do nothing */
 733         if (p == ep->e_secinfo) {
 734                 /* There was no sec= option */
 735                 return;
 736         }
 737         qword_print(f, "secinfo");
 738         qword_printint(f, p - ep->e_secinfo);
 739         for (p = ep->e_secinfo; p->flav; p++) {
 740                 qword_printint(f, p->flav->fnum);
 741                 qword_printint(f, p->flags & flag_mask);
 742         }
 743
 744 }
 745
 746 static int dump_to_cache(FILE *f, char *domain, char *path, struct exportent *exp)
 747 {
 748         qword_print(f, domain);
 749         qword_print(f, path);
 750         if (exp) {
 751                 int different_fs = strcmp(path, exp->e_path) != 0;
 752                 int flag_mask = different_fs ? ~NFSEXP_FSID : ~0;
 753
 754                 qword_printtimefrom(f, exp->e_ttl);
 755                 qword_printint(f, exp->e_flags & flag_mask);
 756                 qword_printint(f, exp->e_anonuid);
 757                 qword_printint(f, exp->e_anongid);
 758                 qword_printint(f, exp->e_fsid);
 759                 write_fsloc(f, exp);
 760                 write_secinfo(f, exp, flag_mask);
 761                 if (exp->e_uuid == NULL || different_fs) {
 762                         char u[16];
 763                         if (uuid_by_path(path, 0, 16, u)) {
 764                                 qword_print(f, "uuid");
 765                                 qword_printhex(f, u, 16);
 766                         }
 767                 } else {
 768                         char u[16];
 769                         get_uuid(exp->e_uuid, 16, u);
 770                         qword_print(f, "uuid");
 771                         qword_printhex(f, u, 16);
 772                 }
 773         } else
 774                 qword_printtimefrom(f, DEFAULT_TTL);
 775         return qword_eol(f);
 776 }
 777
 778 static nfs_export *
 779 lookup_export(char *dom, char *path, struct addrinfo *ai)
 780 {
 781         nfs_export *exp;
 782         nfs_export *found = NULL;
 783         int found_type = 0;
 784         int i;
 785
 786         for (i=0 ; i < MCL_MAXTYPES; i++) {
 787                 for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
 788                         if (!export_matches(exp, dom, path, ai))
 789                                 continue;
 790                         if (!found) {
 791                                 found = exp;
 792                                 found_type = i;
 793                                 continue;
 794                         }
 795                         /* Always prefer non-V4ROOT exports */
 796                         if (exp->m_export.e_flags & NFSEXP_V4ROOT)
 797                                 continue;
 798                         if (found->m_export.e_flags & NFSEXP_V4ROOT) {
 799                                 found = exp;
 800                                 found_type = i;
 801                                 continue;
 802                         }
 803
 804                         /* If one is a CROSSMOUNT, then prefer the longest path */
 805                         if (((found->m_export.e_flags & NFSEXP_CROSSMOUNT) ||
 806                              (exp->m_export.e_flags & NFSEXP_CROSSMOUNT)) &&
 807                             strlen(found->m_export.e_path) !=
 808                             strlen(exp->m_export.e_path)) {
 809
 810                                 if (strlen(exp->m_export.e_path) >
 811                                     strlen(found->m_export.e_path)) {
 812                                         found = exp;
 813                                         found_type = i;
 814                                 }
 815                                 continue;
 816
 817                         } else if (found_type == i && found->m_warned == 0) {
 818                                 xlog(L_WARNING, "%s exported to both %s and %s, "
 819                                      "arbitrarily choosing options from first",
 820                                      path, found->m_client->m_hostname, exp->m_client->m_hostname,
 821                                      dom);
 822                                 found->m_warned = 1;
 823                         }
 824                 }
 825         }
 826         return found;
 827 }
 828
 829 #ifdef HAVE_NFS_PLUGIN_H
 830 #include <dlfcn.h>
 831 #include <link.h>
 832 #include <nfs-plugin.h>
 833
 834 /*
 835  * Find the export entry for the parent of "pathname".
 836  * Caller must not free returned exportent.
 837  */
 838 static struct exportent *lookup_parent_export(char *dom,
 839                 const char *pathname, struct addrinfo *ai)
 840 {
 841         char *parent, *slash;
 842         nfs_export *result;
 843
 844         parent = strdup(pathname);
 845         if (parent == NULL) {
 846                 xlog(D_GENERAL, "%s: failed to allocate parent path buffer",
 847                         __func__);
 848                 goto out_default;
 849         }
 850         xlog(D_CALL, "%s: pathname = '%s'", __func__, pathname);
 851
 852 again:
 853         /* shorten pathname by one component */
 854         slash = strrchr(parent, '/');
 855         if (slash == NULL) {
 856                 xlog(D_GENERAL, "%s: no slash found in pathname",
 857                         __func__);
 858                 goto out_default;
 859         }
 860         *slash = '\0';
 861
 862         if (strlen(parent) == 0) {
 863                 result = lookup_export(dom, "/", ai);
 864                 if (result == NULL) {
 865                         xlog(L_ERROR, "%s: no root export found.", __func__);
 866                         goto out_default;
 867                 }
 868                 goto out;
 869         }
 870
 871         result = lookup_export(dom, parent, ai);
 872         if (result == NULL) {
 873                 xlog(D_GENERAL, "%s: lookup_export(%s) found nothing",
 874                         __func__, parent);
 875                 goto again;
 876         }
 877
 878 out:
 879         xlog(D_CALL, "%s: found export for %s", __func__, parent);
 880         free(parent);
 881         return &result->m_export;
 882
 883 out_default:
 884         free(parent);
 885         return mkexportent("*", "/", "insecure");
 886 }
 887
 888 /*
 889  * Walk through a set of FS locations and build an e_fslocdata string.
 890  * Returns true if all went to plan; otherwise, false.
 891  */
 892 static bool locations_to_fslocdata(struct jp_ops *ops,
 893                 nfs_fsloc_set_t locations, char *fslocdata,
 894                 size_t remaining, int *ttl)
 895 {
 896         char *server, *last_path, *rootpath, *ptr;
 897         _Bool seen = false;
 898
 899         last_path = NULL;
 900         rootpath = NULL;
 901         server = NULL;
 902         ptr = fslocdata;
 903         *ttl = 0;
 904
 905         for (;;) {
 906                 enum jp_status status;
 907                 int len;
 908
 909                 status = ops->jp_get_next_location(locations, &server,
 910                                                         &rootpath, ttl);
 911                 if (status == JP_EMPTY)
 912                         break;
 913                 if (status != JP_OK) {
 914                         xlog(D_GENERAL, "%s: failed to parse location: %s",
 915                                 __func__, ops->jp_error(status));
 916                         goto out_false;
 917                 }
 918                 xlog(D_GENERAL, "%s: Location: %s:%s",
 919                         __func__, server, rootpath);
 920
 921                 if (last_path && strcmp(rootpath, last_path) == 0) {
 922                         len = snprintf(ptr, remaining, "+%s", server);
 923                         if (len < 0) {
 924                                 xlog(D_GENERAL, "%s: snprintf: %m", __func__);
 925                                 goto out_false;
 926                         }
 927                         if ((size_t)len >= remaining) {
 928                                 xlog(D_GENERAL, "%s: fslocdata buffer overflow", __func__);
 929                                 goto out_false;
 930                         }
 931                         remaining -= (size_t)len;
 932                         ptr += len;
 933                 } else {
 934                         if (last_path == NULL)
 935                                 len = snprintf(ptr, remaining, "%s@%s",
 936                                                         rootpath, server);
 937                         else
 938                                 len = snprintf(ptr, remaining, ":%s@%s",
 939                                                         rootpath, server);
 940                         if (len < 0) {
 941                                 xlog(D_GENERAL, "%s: snprintf: %m", __func__);
 942                                 goto out_false;
 943                         }
 944                         if ((size_t)len >= remaining) {
 945                                 xlog(D_GENERAL, "%s: fslocdata buffer overflow",
 946                                         __func__);
 947                                 goto out_false;
 948                         }
 949                         remaining -= (size_t)len;
 950                         ptr += len;
 951                         last_path = rootpath;
 952                 }
 953
 954                 seen = true;
 955                 free(rootpath);
 956                 free(server);
 957         }
 958
 959         xlog(D_CALL, "%s: fslocdata='%s', ttl=%d",
 960                 __func__, fslocdata, *ttl);
 961         return seen;
 962
 963 out_false:
 964         free(rootpath);
 965         free(server);
 966         return false;
 967 }
 968
 969 /*
 970  * Duplicate the junction's parent's export options and graft in
 971  * the fslocdata we constructed from the locations list.
 972  */
 973 static struct exportent *create_junction_exportent(struct exportent *parent,
 974                 const char *junction, const char *fslocdata, int ttl)
 975 {
 976         static struct exportent *eep;
 977
 978         eep = (struct exportent *)malloc(sizeof(*eep));
 979         if (eep == NULL)
 980                 goto out_nomem;
 981
 982         dupexportent(eep, parent);
 983         strcpy(eep->e_path, junction);
 984         eep->e_hostname = strdup(parent->e_hostname);
 985         if (eep->e_hostname == NULL) {
 986                 free(eep);
 987                 goto out_nomem;
 988         }
 989         free(eep->e_uuid);
 990         eep->e_uuid = NULL;
 991         eep->e_ttl = (unsigned int)ttl;
 992
 993         free(eep->e_fslocdata);
 994         eep->e_fslocdata = strdup(fslocdata);
 995         if (eep->e_fslocdata == NULL) {
 996                 free(eep->e_hostname);
 997                 free(eep);
 998                 goto out_nomem;
 999         }
1000         eep->e_fslocmethod = FSLOC_REFER;
1001         return eep;
1002
1003 out_nomem:
1004         xlog(L_ERROR, "%s: No memory", __func__);
1005         return NULL;
1006 }
1007
1008 /*
1009  * Walk through the set of FS locations and build an exportent.
1010  * Returns pointer to an exportent if "junction" refers to a junction.
1011  */
1012 static struct exportent *locations_to_export(struct jp_ops *ops,
1013                 nfs_fsloc_set_t locations, const char *junction,
1014                 struct exportent *parent)
1015 {
1016         static char fslocdata[BUFSIZ];
1017         int ttl;
1018
1019         fslocdata[0] = '\0';
1020         if (!locations_to_fslocdata(ops, locations,
1021                                         fslocdata, sizeof(fslocdata), &ttl))
1022                 return NULL;
1023         return create_junction_exportent(parent, junction, fslocdata, ttl);
1024 }
1025
1026 /*
1027  * Retrieve locations information in "junction" and dump it to the
1028  * kernel.  Returns pointer to an exportent if "junction" refers
1029  * to a junction.
1030  */
1031 static struct exportent *invoke_junction_ops(void *handle, char *dom,
1032                 const char *junction, struct addrinfo *ai)
1033 {
1034         struct exportent *parent, *exp = NULL;
1035         nfs_fsloc_set_t locations;
1036         enum jp_status status;
1037         struct jp_ops *ops;
1038         char *error;
1039
1040         ops = (struct jp_ops *)dlsym(handle, "nfs_junction_ops");
1041         error = dlerror();
1042         if (error != NULL) {
1043                 xlog(D_GENERAL, "%s: dlsym(jp_junction_ops): %s",
1044                         __func__, error);
1045                 return NULL;
1046         }
1047         if (ops->jp_api_version != JP_API_VERSION) {
1048                 xlog(D_GENERAL, "%s: unrecognized junction API version: %u",
1049                         __func__, ops->jp_api_version);
1050                 return NULL;
1051         }
1052
1053         status = ops->jp_init(false);
1054         if (status != JP_OK) {
1055                 xlog(D_GENERAL, "%s: failed to resolve %s: %s",
1056                         __func__, junction, ops->jp_error(status));
1057                 return NULL;
1058         }
1059
1060         status = ops->jp_get_locations(junction, &locations);
1061         switch (status) {
1062         case JP_OK:
1063                 break;
1064         case JP_NOTJUNCTION:
1065                 xlog(D_GENERAL, "%s: %s is not a junction",
1066                         __func__, junction);
1067                 goto out;
1068         default:
1069                 xlog(L_WARNING, "Dangling junction %s: %s",
1070                         junction, ops->jp_error(status));
1071                 goto out;
1072         }
1073
1074         parent = lookup_parent_export(dom, junction, ai);
1075         if (parent == NULL)
1076                 goto out;
1077
1078         exp = locations_to_export(ops, locations, junction, parent);
1079
1080         ops->jp_put_locations(locations);
1081
1082 out:
1083         ops->jp_done();
1084         return exp;
1085 }
1086
1087 /*
1088  * Load the junction plug-in, then try to resolve "pathname".
1089  * Returns pointer to an initialized exportent if "junction"
1090  * refers to a junction, or NULL if not.
1091  */
1092 static struct exportent *lookup_junction(char *dom, const char *pathname,
1093                 struct addrinfo *ai)
1094 {
1095         struct exportent *exp;
1096         struct link_map *map;
1097         void *handle;
1098
1099         handle = dlopen("libnfsjunct.so", RTLD_NOW);
1100         if (handle == NULL) {
1101                 xlog(D_GENERAL, "%s: dlopen: %s", __func__, dlerror());
1102                 return NULL;
1103         }
1104
1105         if (dlinfo(handle, RTLD_DI_LINKMAP, &map) == 0)
1106                 xlog(D_GENERAL, "%s: loaded plug-in %s",
1107                         __func__, map->l_name);
1108
1109         (void)dlerror();        /* Clear any error */
1110
1111         exp = invoke_junction_ops(handle, dom, pathname, ai);
1112
1113         /* We could leave it loaded to make junction resolution
1114          * faster next time.  However, if we want to replace the
1115          * library, that would require restarting mountd. */
1116         (void)dlclose(handle);
1117         return exp;
1118 }
1119
1120 static void lookup_nonexport(FILE *f, char *dom, char *path,
1121                 struct addrinfo *ai)
1122 {
1123         struct exportent *eep;
1124
1125         eep = lookup_junction(dom, path, ai);
1126         dump_to_cache(f, dom, path, eep);
1127         if (eep == NULL)
1128                 return;
1129         exportent_release(eep);
1130         free(eep);
1131 }
1132 #else   /* !HAVE_NFS_PLUGIN_H */
1133 static void lookup_nonexport(FILE *f, char *dom, char *path,
1134                 struct addrinfo *UNUSED(ai))
1135 {
1136         dump_to_cache(f, dom, path, NULL);
1137 }
1138 #endif  /* !HAVE_NFS_PLUGIN_H */
1139
1140 static void nfsd_export(FILE *f)
1141 {
1142         /* requests are:
1143          *  domain path
1144          * determine export options and return:
1145          *  domain path expiry flags anonuid anongid fsid
1146          */
1147
1148         char *cp;
1149         char *dom, *path;
1150         nfs_export *found = NULL;
1151         struct addrinfo *ai = NULL;
1152
1153         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
1154                 return;
1155
1156         xlog(D_CALL, "nfsd_export: inbuf '%s'", lbuf);
1157
1158         cp = lbuf;
1159         dom = malloc(strlen(cp));
1160         path = malloc(strlen(cp));
1161
1162         if (!dom || !path)
1163                 goto out;
1164
1165         if (qword_get(&cp, dom, strlen(lbuf)) <= 0)
1166                 goto out;
1167         if (qword_get(&cp, path, strlen(lbuf)) <= 0)
1168                 goto out;
1169
1170         auth_reload();
1171
1172         if (is_ipaddr_client(dom)) {
1173                 ai = lookup_client_addr(dom);
1174                 if (!ai)
1175                         goto out;
1176         }
1177
1178         found = lookup_export(dom, path, ai);
1179
1180         if (found) {
1181                 if (dump_to_cache(f, dom, path, &found->m_export) < 0) {
1182                         xlog(L_WARNING,
1183                              "Cannot export %s, possibly unsupported filesystem"
1184                              " or fsid= required", path);
1185                         dump_to_cache(f, dom, path, NULL);
1186                 }
1187         } else
1188                 lookup_nonexport(f, dom, path, ai);
1189
1190  out:
1191         xlog(D_CALL, "nfsd_export: found %p path %s", found, path ? path : NULL);
1192         if (dom) free(dom);
1193         if (path) free(path);
1194         freeaddrinfo(ai);
1195 }
1196
1197
1198 struct {
1199         char *cache_name;
1200         void (*cache_handle)(FILE *f);
1201         FILE *f;
1202         char vbuf[RPC_CHAN_BUF_SIZE];
1203 } cachelist[] = {
1204         { "auth.unix.ip", auth_unix_ip, NULL, ""},
1205         { "auth.unix.gid", auth_unix_gid, NULL, ""},
1206         { "nfsd.export", nfsd_export, NULL, ""},
1207         { "nfsd.fh", nfsd_fh, NULL, ""},
1208         { NULL, NULL, NULL, ""}
1209 };
1210
1211 extern int manage_gids;
1212
1213 /**
1214  * cache_open - prepare communications channels with kernel RPC caches
1215  *
1216  */
1217 void cache_open(void)
1218 {
1219         int i;
1220         for (i=0; cachelist[i].cache_name; i++ ) {
1221                 char path[100];
1222                 if (!manage_gids && cachelist[i].cache_handle == auth_unix_gid)
1223                         continue;
1224                 sprintf(path, "/proc/net/rpc/%s/channel", cachelist[i].cache_name);
1225                 cachelist[i].f = fopen(path, "r+");
1226                 if (cachelist[i].f != NULL) {
1227                         setvbuf(cachelist[i].f, cachelist[i].vbuf, _IOLBF,
1228                                 RPC_CHAN_BUF_SIZE);
1229                 }
1230         }
1231 }
1232
1233 /**
1234  * cache_set_fds - prepare cache file descriptors for one iteration of the service loop
1235  * @fdset: pointer to fd_set to prepare
1236  */
1237 void cache_set_fds(fd_set *fdset)
1238 {
1239         int i;
1240         for (i=0; cachelist[i].cache_name; i++) {
1241                 if (cachelist[i].f)
1242                         FD_SET(fileno(cachelist[i].f), fdset);
1243         }
1244 }
1245
1246 /**
1247  * cache_process_req - process any active cache file descriptors during service loop iteration
1248  * @fdset: pointer to fd_set to examine for activity
1249  */
1250 int cache_process_req(fd_set *readfds)
1251 {
1252         int i;
1253         int cnt = 0;
1254         for (i=0; cachelist[i].cache_name; i++) {
1255                 if (cachelist[i].f != NULL &&
1256                     FD_ISSET(fileno(cachelist[i].f), readfds)) {
1257                         cnt++;
1258                         cachelist[i].cache_handle(cachelist[i].f);
1259                         FD_CLR(fileno(cachelist[i].f), readfds);
1260                 }
1261         }
1262         return cnt;
1263 }
1264
1265
1266 /*
1267  * Give IP->domain and domain+path->options to kernel
1268  * % echo nfsd $IP  $[now+DEFAULT_TTL] $domain > /proc/net/rpc/auth.unix.ip/channel
1269  * % echo $domain $path $[now+DEFAULT_TTL] $options $anonuid $anongid $fsid > /proc/net/rpc/nfsd.export/channel
1270  */
1271
1272 static int cache_export_ent(char *domain, struct exportent *exp, char *path)
1273 {
1274         int err;
1275         FILE *f = fopen("/proc/net/rpc/nfsd.export/channel", "w");
1276         if (!f)
1277                 return -1;
1278
1279         err = dump_to_cache(f, domain, exp->e_path, exp);
1280         if (err) {
1281                 xlog(L_WARNING,
1282                      "Cannot export %s, possibly unsupported filesystem or"
1283                      " fsid= required", exp->e_path);
1284         }
1285
1286         while (err == 0 && (exp->e_flags & NFSEXP_CROSSMOUNT) && path) {
1287                 /* really an 'if', but we can break out of
1288                  * a 'while' more easily */
1289                 /* Look along 'path' for other filesystems
1290                  * and export them with the same options
1291                  */
1292                 struct stat stb;
1293                 size_t l = strlen(exp->e_path);
1294                 __dev_t dev;
1295
1296                 if (strlen(path) <= l || path[l] != '/' ||
1297                     strncmp(exp->e_path, path, l) != 0)
1298                         break;
1299                 if (stat(exp->e_path, &stb) != 0)
1300                         break;
1301                 dev = stb.st_dev;
1302                 while(path[l] == '/') {
1303                         char c;
1304                         /* errors for submount should fail whole filesystem */
1305                         int err2;
1306
1307                         l++;
1308                         while (path[l] != '/' && path[l])
1309                                 l++;
1310                         c = path[l];
1311                         path[l] = 0;
1312                         err2 = lstat(path, &stb);
1313                         path[l] = c;
1314                         if (err2 < 0)
1315                                 break;
1316                         if (stb.st_dev == dev)
1317                                 continue;
1318                         dev = stb.st_dev;
1319                         path[l] = 0;
1320                         dump_to_cache(f, domain, path, exp);
1321                         path[l] = c;
1322                 }
1323                 break;
1324         }
1325
1326         fclose(f);
1327         return err;
1328 }
1329
1330 /**
1331  * cache_export - Inform kernel of a new nfs_export
1332  * @exp: target nfs_export
1333  * @path: NUL-terminated C string containing export path
1334  */
1335 int cache_export(nfs_export *exp, char *path)
1336 {
1337         char buf[INET6_ADDRSTRLEN];
1338         int err;
1339         FILE *f;
1340
1341         f = fopen("/proc/net/rpc/auth.unix.ip/channel", "w");
1342         if (!f)
1343                 return -1;
1344
1345
1346         qword_print(f, "nfsd");
1347         qword_print(f,
1348                 host_ntop(get_addrlist(exp->m_client, 0), buf, sizeof(buf)));
1349         qword_printtimefrom(f, exp->m_export.e_ttl);
1350         qword_print(f, exp->m_client->m_hostname);
1351         err = qword_eol(f);
1352
1353         fclose(f);
1354
1355         err = cache_export_ent(exp->m_client->m_hostname, &exp->m_export, path)
1356                 || err;
1357         return err;
1358 }
1359
1360 /**
1361  * cache_get_filehandle - given an nfs_export, get its root filehandle
1362  * @exp: target nfs_export
1363  * @len: length of requested file handle
1364  * @p: NUL-terminated C string containing export path
1365  *
1366  * Returns pointer to NFS file handle of root directory of export
1367  *
1368  * {
1369  *   echo $domain $path $length
1370  *   read filehandle <&0
1371  * } <> /proc/fs/nfsd/filehandle
1372  */
1373 struct nfs_fh_len *
1374 cache_get_filehandle(nfs_export *exp, int len, char *p)
1375 {
1376         FILE *f = fopen("/proc/fs/nfsd/filehandle", "r+");
1377         char buf[200];
1378         char *bp = buf;
1379         int failed;
1380         static struct nfs_fh_len fh;
1381
1382         if (!f)
1383                 f = fopen("/proc/fs/nfs/filehandle", "r+");
1384         if (!f)
1385                 return NULL;
1386
1387         qword_print(f, exp->m_client->m_hostname);
1388         qword_print(f, p);
1389         qword_printint(f, len);
1390         failed = qword_eol(f);
1391
1392         if (!failed)
1393                 failed = (fgets(buf, sizeof(buf), f) == NULL);
1394         fclose(f);
1395         if (failed)
1396                 return NULL;
1397         memset(fh.fh_handle, 0, sizeof(fh.fh_handle));
1398         fh.fh_size = qword_get(&bp, (char *)fh.fh_handle, NFS3_FHSIZE);
1399         return &fh;
1400 }