utils/mountd/cache.c

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