util-linux/mount.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini mount implementation for busybox
   4  *
   5  * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
   6  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
   7  * Copyright (C) 2005-2006 by Rob Landley <rob@landley.net>
   8  *
   9  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  10  */
  11 // Design notes: There is no spec for mount.  Remind me to write one.
  12 //
  13 // mount_main() calls singlemount() which calls mount_it_now().
  14 //
  15 // mount_main() can loop through /etc/fstab for mount -a
  16 // singlemount() can loop through /etc/filesystems for fstype detection.
  17 // mount_it_now() does the actual mount.
  18 //
  19 #include <mntent.h>
  20 #include <syslog.h>
  21 #include <sys/mount.h>
  22 // Grab more as needed from util-linux's mount/mount_constants.h
  23 #ifndef MS_DIRSYNC
  24 # define MS_DIRSYNC     (1 << 7) // Directory modifications are synchronous
  25 #endif
  26 #ifndef MS_UNION
  27 # define MS_UNION       (1 << 8)
  28 #endif
  29 #ifndef MS_BIND
  30 # define MS_BIND        (1 << 12)
  31 #endif
  32 #ifndef MS_MOVE
  33 # define MS_MOVE        (1 << 13)
  34 #endif
  35 #ifndef MS_RECURSIVE
  36 # define MS_RECURSIVE   (1 << 14)
  37 #endif
  38 #ifndef MS_SILENT
  39 # define MS_SILENT      (1 << 15)
  40 #endif
  41 // The shared subtree stuff, which went in around 2.6.15
  42 #ifndef MS_UNBINDABLE
  43 # define MS_UNBINDABLE  (1 << 17)
  44 #endif
  45 #ifndef MS_PRIVATE
  46 # define MS_PRIVATE     (1 << 18)
  47 #endif
  48 #ifndef MS_SLAVE
  49 # define MS_SLAVE       (1 << 19)
  50 #endif
  51 #ifndef MS_SHARED
  52 # define MS_SHARED      (1 << 20)
  53 #endif
  54 #ifndef MS_RELATIME
  55 # define MS_RELATIME    (1 << 21)
  56 #endif
  57
  58 #include "libbb.h"
  59 #if ENABLE_FEATURE_MOUNT_LABEL
  60 # include "volume_id.h"
  61 #else
  62 # define resolve_mount_spec(fsname) ((void)0)
  63 #endif
  64
  65 // Needed for nfs support only
  66 #include <sys/utsname.h>
  67 #undef TRUE
  68 #undef FALSE
  69 #if ENABLE_FEATURE_MOUNT_NFS
  70 /* This is just a warning of a common mistake.  Possibly this should be a
  71  * uclibc faq entry rather than in busybox... */
  72 # if defined(__UCLIBC__) && ! defined(__UCLIBC_HAS_RPC__)
  73 #  error "You need to build uClibc with UCLIBC_HAS_RPC for NFS support"
  74 # endif
  75 # include <rpc/rpc.h>
  76 # include <rpc/pmap_prot.h>
  77 # include <rpc/pmap_clnt.h>
  78 #endif
  79
  80
  81 #if defined(__dietlibc__)
  82 // 16.12.2006, Sampo Kellomaki (sampo@iki.fi)
  83 // dietlibc-0.30 does not have implementation of getmntent_r()
  84 static struct mntent *getmntent_r(FILE* stream, struct mntent* result,
  85                 char* buffer UNUSED_PARAM, int bufsize UNUSED_PARAM)
  86 {
  87         struct mntent* ment = getmntent(stream);
  88         return memcpy(result, ment, sizeof(*ment));
  89 }
  90 #endif
  91
  92
  93 // Not real flags, but we want to be able to check for this.
  94 enum {
  95         MOUNT_USERS  = (1 << 28) * ENABLE_DESKTOP,
  96         MOUNT_NOAUTO = (1 << 29),
  97         MOUNT_SWAP   = (1 << 30),
  98 };
  99
 100
 101 #define OPTION_STR "o:t:rwanfvsiO:"
 102 enum {
 103         OPT_o = (1 << 0),
 104         OPT_t = (1 << 1),
 105         OPT_r = (1 << 2),
 106         OPT_w = (1 << 3),
 107         OPT_a = (1 << 4),
 108         OPT_n = (1 << 5),
 109         OPT_f = (1 << 6),
 110         OPT_v = (1 << 7),
 111         OPT_s = (1 << 8),
 112         OPT_i = (1 << 9),
 113         OPT_O = (1 << 10),
 114 };
 115
 116 #if ENABLE_FEATURE_MTAB_SUPPORT
 117 #define USE_MTAB (!(option_mask32 & OPT_n))
 118 #else
 119 #define USE_MTAB 0
 120 #endif
 121
 122 #if ENABLE_FEATURE_MOUNT_FAKE
 123 #define FAKE_IT (option_mask32 & OPT_f)
 124 #else
 125 #define FAKE_IT 0
 126 #endif
 127
 128 #if ENABLE_FEATURE_MOUNT_HELPERS
 129 #define HELPERS_ALLOWED (!(option_mask32 & OPT_i))
 130 #else
 131 #define HELPERS_ALLOWED 0
 132 #endif
 133
 134
 135 // TODO: more "user" flag compatibility.
 136 // "user" option (from mount manpage):
 137 // Only the user that mounted a filesystem can unmount it again.
 138 // If any user should be able to unmount, then use users instead of user
 139 // in the fstab line.  The owner option is similar to the user option,
 140 // with the restriction that the user must be the owner of the special file.
 141 // This may be useful e.g. for /dev/fd if a login script makes
 142 // the console user owner of this device.
 143
 144 // Standard mount options (from -o options or --options),
 145 // with corresponding flags
 146 static const int32_t mount_options[] = {
 147         // MS_FLAGS set a bit.  ~MS_FLAGS disable that bit.  0 flags are NOPs.
 148
 149         IF_FEATURE_MOUNT_LOOP(
 150                 /* "loop" */ 0,
 151         )
 152
 153         IF_FEATURE_MOUNT_FSTAB(
 154                 /* "defaults" */ 0,
 155                 /* "quiet" 0 - do not filter out, vfat wants to see it */
 156                 /* "noauto" */ MOUNT_NOAUTO,
 157                 /* "sw"     */ MOUNT_SWAP,
 158                 /* "swap"   */ MOUNT_SWAP,
 159                 IF_DESKTOP(/* "user"  */ MOUNT_USERS,)
 160                 IF_DESKTOP(/* "users" */ MOUNT_USERS,)
 161                 /* "_netdev" */ 0,
 162         )
 163
 164         IF_FEATURE_MOUNT_FLAGS(
 165                 // vfs flags
 166                 /* "nosuid"      */ MS_NOSUID,
 167                 /* "suid"        */ ~MS_NOSUID,
 168                 /* "dev"         */ ~MS_NODEV,
 169                 /* "nodev"       */ MS_NODEV,
 170                 /* "exec"        */ ~MS_NOEXEC,
 171                 /* "noexec"      */ MS_NOEXEC,
 172                 /* "sync"        */ MS_SYNCHRONOUS,
 173                 /* "dirsync"     */ MS_DIRSYNC,
 174                 /* "async"       */ ~MS_SYNCHRONOUS,
 175                 /* "atime"       */ ~MS_NOATIME,
 176                 /* "noatime"     */ MS_NOATIME,
 177                 /* "diratime"    */ ~MS_NODIRATIME,
 178                 /* "nodiratime"  */ MS_NODIRATIME,
 179                 /* "mand"        */ MS_MANDLOCK,
 180                 /* "nomand"      */ ~MS_MANDLOCK,
 181                 /* "relatime"    */ MS_RELATIME,
 182                 /* "norelatime"  */ ~MS_RELATIME,
 183                 /* "loud"        */ ~MS_SILENT,
 184
 185                 // action flags
 186                 /* "union"       */ MS_UNION,
 187                 /* "bind"        */ MS_BIND,
 188                 /* "move"        */ MS_MOVE,
 189                 /* "shared"      */ MS_SHARED,
 190                 /* "slave"       */ MS_SLAVE,
 191                 /* "private"     */ MS_PRIVATE,
 192                 /* "unbindable"  */ MS_UNBINDABLE,
 193                 /* "rshared"     */ MS_SHARED|MS_RECURSIVE,
 194                 /* "rslave"      */ MS_SLAVE|MS_RECURSIVE,
 195                 /* "rprivate"    */ MS_SLAVE|MS_RECURSIVE,
 196                 /* "runbindable" */ MS_UNBINDABLE|MS_RECURSIVE,
 197         )
 198
 199         // Always understood.
 200         /* "ro"      */ MS_RDONLY,  // vfs flag
 201         /* "rw"      */ ~MS_RDONLY, // vfs flag
 202         /* "remount" */ MS_REMOUNT  // action flag
 203 };
 204
 205 static const char mount_option_str[] =
 206         IF_FEATURE_MOUNT_LOOP(
 207                 "loop\0"
 208         )
 209         IF_FEATURE_MOUNT_FSTAB(
 210                 "defaults\0"
 211                 // "quiet\0" - do not filter out, vfat wants to see it
 212                 "noauto\0"
 213                 "sw\0"
 214                 "swap\0"
 215                 IF_DESKTOP("user\0")
 216                 IF_DESKTOP("users\0")
 217                 "_netdev\0"
 218         )
 219         IF_FEATURE_MOUNT_FLAGS(
 220                 // vfs flags
 221                 "nosuid\0"
 222                 "suid\0"
 223                 "dev\0"
 224                 "nodev\0"
 225                 "exec\0"
 226                 "noexec\0"
 227                 "sync\0"
 228                 "dirsync\0"
 229                 "async\0"
 230                 "atime\0"
 231                 "noatime\0"
 232                 "diratime\0"
 233                 "nodiratime\0"
 234                 "mand\0"
 235                 "nomand\0"
 236                 "relatime\0"
 237                 "norelatime\0"
 238                 "loud\0"
 239
 240                 // action flags
 241                 "union\0"
 242                 "bind\0"
 243                 "move\0"
 244                 "shared\0"
 245                 "slave\0"
 246                 "private\0"
 247                 "unbindable\0"
 248                 "rshared\0"
 249                 "rslave\0"
 250                 "rprivate\0"
 251                 "runbindable\0"
 252         )
 253
 254         // Always understood.
 255         "ro\0"        // vfs flag
 256         "rw\0"        // vfs flag
 257         "remount\0"   // action flag
 258 ;
 259
 260
 261 struct globals {
 262 #if ENABLE_FEATURE_MOUNT_NFS
 263         smalluint nfs_mount_version;
 264 #endif
 265 #if ENABLE_FEATURE_MOUNT_VERBOSE
 266         unsigned verbose;
 267 #endif
 268         llist_t *fslist;
 269         char getmntent_buf[1];
 270 } FIX_ALIASING;
 271 enum { GETMNTENT_BUFSIZE = COMMON_BUFSIZE - offsetof(struct globals, getmntent_buf) };
 272 #define G (*(struct globals*)&bb_common_bufsiz1)
 273 #define nfs_mount_version (G.nfs_mount_version)
 274 #if ENABLE_FEATURE_MOUNT_VERBOSE
 275 #define verbose           (G.verbose          )
 276 #else
 277 #define verbose           0
 278 #endif
 279 #define fslist            (G.fslist           )
 280 #define getmntent_buf     (G.getmntent_buf    )
 281
 282
 283 #if ENABLE_FEATURE_MOUNT_VERBOSE
 284 static int verbose_mount(const char *source, const char *target,
 285                 const char *filesystemtype,
 286                 unsigned long mountflags, const void *data)
 287 {
 288         int rc;
 289
 290         errno = 0;
 291         rc = mount(source, target, filesystemtype, mountflags, data);
 292         if (verbose >= 2)
 293                 bb_perror_msg("mount('%s','%s','%s',0x%08lx,'%s'):%d",
 294                         source, target, filesystemtype,
 295                         mountflags, (char*)data, rc);
 296         return rc;
 297 }
 298 #else
 299 #define verbose_mount(...) mount(__VA_ARGS__)
 300 #endif
 301
 302 // Append mount options to string
 303 static void append_mount_options(char **oldopts, const char *newopts)
 304 {
 305         if (*oldopts && **oldopts) {
 306                 // Do not insert options which are already there
 307                 while (newopts[0]) {
 308                         char *p;
 309                         int len = strlen(newopts);
 310                         p = strchr(newopts, ',');
 311                         if (p) len = p - newopts;
 312                         p = *oldopts;
 313                         while (1) {
 314                                 if (!strncmp(p, newopts, len)
 315                                  && (p[len] == ',' || p[len] == '\0'))
 316                                         goto skip;
 317                                 p = strchr(p,',');
 318                                 if (!p) break;
 319                                 p++;
 320                         }
 321                         p = xasprintf("%s,%.*s", *oldopts, len, newopts);
 322                         free(*oldopts);
 323                         *oldopts = p;
 324  skip:
 325                         newopts += len;
 326                         while (newopts[0] == ',') newopts++;
 327                 }
 328         } else {
 329                 if (ENABLE_FEATURE_CLEAN_UP) free(*oldopts);
 330                 *oldopts = xstrdup(newopts);
 331         }
 332 }
 333
 334 // Use the mount_options list to parse options into flags.
 335 // Also return list of unrecognized options if unrecognized != NULL
 336 static long parse_mount_options(char *options, char **unrecognized)
 337 {
 338         long flags = MS_SILENT;
 339
 340         // Loop through options
 341         for (;;) {
 342                 unsigned i;
 343                 char *comma = strchr(options, ',');
 344                 const char *option_str = mount_option_str;
 345
 346                 if (comma) *comma = '\0';
 347
 348 // FIXME: use hasmntopt()
 349                 // Find this option in mount_options
 350                 for (i = 0; i < ARRAY_SIZE(mount_options); i++) {
 351                         if (!strcasecmp(option_str, options)) {
 352                                 long fl = mount_options[i];
 353                                 if (fl < 0) flags &= fl;
 354                                 else flags |= fl;
 355                                 break;
 356                         }
 357                         option_str += strlen(option_str) + 1;
 358                 }
 359                 // If unrecognized not NULL, append unrecognized mount options
 360                 if (unrecognized && i == ARRAY_SIZE(mount_options)) {
 361                         // Add it to strflags, to pass on to kernel
 362                         i = *unrecognized ? strlen(*unrecognized) : 0;
 363                         *unrecognized = xrealloc(*unrecognized, i + strlen(options) + 2);
 364
 365                         // Comma separated if it's not the first one
 366                         if (i) (*unrecognized)[i++] = ',';
 367                         strcpy((*unrecognized)+i, options);
 368                 }
 369
 370                 if (!comma)
 371                         break;
 372                 // Advance to next option
 373                 *comma = ',';
 374                 options = ++comma;
 375         }
 376
 377         return flags;
 378 }
 379
 380 // Return a list of all block device backed filesystems
 381 static llist_t *get_block_backed_filesystems(void)
 382 {
 383         static const char filesystems[2][sizeof("/proc/filesystems")] = {
 384                 "/etc/filesystems",
 385                 "/proc/filesystems",
 386         };
 387         char *fs, *buf;
 388         llist_t *list = NULL;
 389         int i;
 390         FILE *f;
 391
 392         for (i = 0; i < 2; i++) {
 393                 f = fopen_for_read(filesystems[i]);
 394                 if (!f) continue;
 395
 396                 while ((buf = xmalloc_fgetline(f)) != NULL) {
 397                         if (strncmp(buf, "nodev", 5) == 0 && isspace(buf[5]))
 398                                 continue;
 399                         fs = skip_whitespace(buf);
 400                         if (*fs == '#' || *fs == '*' || !*fs)
 401                                 continue;
 402
 403                         llist_add_to_end(&list, xstrdup(fs));
 404                         free(buf);
 405                 }
 406                 if (ENABLE_FEATURE_CLEAN_UP) fclose(f);
 407         }
 408
 409         return list;
 410 }
 411
 412 #if ENABLE_FEATURE_CLEAN_UP
 413 static void delete_block_backed_filesystems(void)
 414 {
 415         llist_free(fslist, free);
 416 }
 417 #else
 418 void delete_block_backed_filesystems(void);
 419 #endif
 420
 421 // Perform actual mount of specific filesystem at specific location.
 422 // NB: mp->xxx fields may be trashed on exit
 423 static int mount_it_now(struct mntent *mp, long vfsflags, char *filteropts)
 424 {
 425         int rc = 0;
 426
 427         if (FAKE_IT) {
 428                 if (verbose >= 2)
 429                         bb_error_msg("would do mount('%s','%s','%s',0x%08lx,'%s')",
 430                                 mp->mnt_fsname, mp->mnt_dir, mp->mnt_type,
 431                                 vfsflags, filteropts);
 432                 goto mtab;
 433         }
 434
 435         // Mount, with fallback to read-only if necessary.
 436         for (;;) {
 437                 errno = 0;
 438                 rc = verbose_mount(mp->mnt_fsname, mp->mnt_dir, mp->mnt_type,
 439                                 vfsflags, filteropts);
 440
 441                 // If mount failed, try
 442                 // helper program mount.<mnt_type>
 443                 if (HELPERS_ALLOWED && rc && mp->mnt_type) {
 444                         char *args[8];
 445                         int errno_save = errno;
 446                         args[0] = xasprintf("mount.%s", mp->mnt_type);
 447                         rc = 1;
 448                         if (FAKE_IT)
 449                                 args[rc++] = (char *)"-f";
 450                         if (ENABLE_FEATURE_MTAB_SUPPORT && !USE_MTAB)
 451                                 args[rc++] = (char *)"-n";
 452                         args[rc++] = mp->mnt_fsname;
 453                         args[rc++] = mp->mnt_dir;
 454                         if (filteropts) {
 455                                 args[rc++] = (char *)"-o";
 456                                 args[rc++] = filteropts;
 457                         }
 458                         args[rc] = NULL;
 459                         rc = wait4pid(spawn(args));
 460                         free(args[0]);
 461                         if (!rc)
 462                                 break;
 463                         errno = errno_save;
 464                 }
 465
 466                 if (!rc || (vfsflags & MS_RDONLY) || (errno != EACCES && errno != EROFS))
 467                         break;
 468                 if (!(vfsflags & MS_SILENT))
 469                         bb_error_msg("%s is write-protected, mounting read-only",
 470                                                 mp->mnt_fsname);
 471                 vfsflags |= MS_RDONLY;
 472         }
 473
 474         // Abort entirely if permission denied.
 475
 476         if (rc && errno == EPERM)
 477                 bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
 478
 479         // If the mount was successful, and we're maintaining an old-style
 480         // mtab file by hand, add the new entry to it now.
 481  mtab:
 482         if (USE_MTAB && !rc && !(vfsflags & MS_REMOUNT)) {
 483                 char *fsname;
 484                 FILE *mountTable = setmntent(bb_path_mtab_file, "a+");
 485                 const char *option_str = mount_option_str;
 486                 int i;
 487
 488                 if (!mountTable) {
 489                         bb_error_msg("no %s", bb_path_mtab_file);
 490                         goto ret;
 491                 }
 492
 493                 // Add vfs string flags
 494
 495                 for (i = 0; mount_options[i] != MS_REMOUNT; i++) {
 496                         if (mount_options[i] > 0 && (mount_options[i] & vfsflags))
 497                                 append_mount_options(&(mp->mnt_opts), option_str);
 498                         option_str += strlen(option_str) + 1;
 499                 }
 500
 501                 // Remove trailing / (if any) from directory we mounted on
 502
 503                 i = strlen(mp->mnt_dir) - 1;
 504                 if (i > 0 && mp->mnt_dir[i] == '/') mp->mnt_dir[i] = '\0';
 505
 506                 // Convert to canonical pathnames as needed
 507
 508                 mp->mnt_dir = bb_simplify_path(mp->mnt_dir);
 509                 fsname = 0;
 510                 if (!mp->mnt_type || !*mp->mnt_type) { // bind mount
 511                         mp->mnt_fsname = fsname = bb_simplify_path(mp->mnt_fsname);
 512                         mp->mnt_type = (char*)"bind";
 513                 }
 514                 mp->mnt_freq = mp->mnt_passno = 0;
 515
 516                 // Write and close.
 517
 518                 addmntent(mountTable, mp);
 519                 endmntent(mountTable);
 520                 if (ENABLE_FEATURE_CLEAN_UP) {
 521                         free(mp->mnt_dir);
 522                         free(fsname);
 523                 }
 524         }
 525  ret:
 526         return rc;
 527 }
 528
 529 #if ENABLE_FEATURE_MOUNT_NFS
 530
 531 /*
 532  * Linux NFS mount
 533  * Copyright (C) 1993 Rick Sladkey <jrs@world.std.com>
 534  *
 535  * Licensed under GPLv2, see file LICENSE in this tarball for details.
 536  *
 537  * Wed Feb  8 12:51:48 1995, biro@yggdrasil.com (Ross Biro): allow all port
 538  * numbers to be specified on the command line.
 539  *
 540  * Fri, 8 Mar 1996 18:01:39, Swen Thuemmler <swen@uni-paderborn.de>:
 541  * Omit the call to connect() for Linux version 1.3.11 or later.
 542  *
 543  * Wed Oct  1 23:55:28 1997: Dick Streefland <dick_streefland@tasking.com>
 544  * Implemented the "bg", "fg" and "retry" mount options for NFS.
 545  *
 546  * 1999-02-22 Arkadiusz Mickiewicz <misiek@misiek.eu.org>
 547  * - added Native Language Support
 548  *
 549  * Modified by Olaf Kirch and Trond Myklebust for new NFS code,
 550  * plus NFSv3 stuff.
 551  */
 552
 553 #define MOUNTPORT 635
 554 #define MNTPATHLEN 1024
 555 #define MNTNAMLEN 255
 556 #define FHSIZE 32
 557 #define FHSIZE3 64
 558
 559 typedef char fhandle[FHSIZE];
 560
 561 typedef struct {
 562         unsigned int fhandle3_len;
 563         char *fhandle3_val;
 564 } fhandle3;
 565
 566 enum mountstat3 {
 567         MNT_OK = 0,
 568         MNT3ERR_PERM = 1,
 569         MNT3ERR_NOENT = 2,
 570         MNT3ERR_IO = 5,
 571         MNT3ERR_ACCES = 13,
 572         MNT3ERR_NOTDIR = 20,
 573         MNT3ERR_INVAL = 22,
 574         MNT3ERR_NAMETOOLONG = 63,
 575         MNT3ERR_NOTSUPP = 10004,
 576         MNT3ERR_SERVERFAULT = 10006,
 577 };
 578 typedef enum mountstat3 mountstat3;
 579
 580 struct fhstatus {
 581         unsigned int fhs_status;
 582         union {
 583                 fhandle fhs_fhandle;
 584         } fhstatus_u;
 585 };
 586 typedef struct fhstatus fhstatus;
 587
 588 struct mountres3_ok {
 589         fhandle3 fhandle;
 590         struct {
 591                 unsigned int auth_flavours_len;
 592                 char *auth_flavours_val;
 593         } auth_flavours;
 594 };
 595 typedef struct mountres3_ok mountres3_ok;
 596
 597 struct mountres3 {
 598         mountstat3 fhs_status;
 599         union {
 600                 mountres3_ok mountinfo;
 601         } mountres3_u;
 602 };
 603 typedef struct mountres3 mountres3;
 604
 605 typedef char *dirpath;
 606
 607 typedef char *name;
 608
 609 typedef struct mountbody *mountlist;
 610
 611 struct mountbody {
 612         name ml_hostname;
 613         dirpath ml_directory;
 614         mountlist ml_next;
 615 };
 616 typedef struct mountbody mountbody;
 617
 618 typedef struct groupnode *groups;
 619
 620 struct groupnode {
 621         name gr_name;
 622         groups gr_next;
 623 };
 624 typedef struct groupnode groupnode;
 625
 626 typedef struct exportnode *exports;
 627
 628 struct exportnode {
 629         dirpath ex_dir;
 630         groups ex_groups;
 631         exports ex_next;
 632 };
 633 typedef struct exportnode exportnode;
 634
 635 struct ppathcnf {
 636         int pc_link_max;
 637         short pc_max_canon;
 638         short pc_max_input;
 639         short pc_name_max;
 640         short pc_path_max;
 641         short pc_pipe_buf;
 642         uint8_t pc_vdisable;
 643         char pc_xxx;
 644         short pc_mask[2];
 645 };
 646 typedef struct ppathcnf ppathcnf;
 647
 648 #define MOUNTPROG 100005
 649 #define MOUNTVERS 1
 650
 651 #define MOUNTPROC_NULL 0
 652 #define MOUNTPROC_MNT 1
 653 #define MOUNTPROC_DUMP 2
 654 #define MOUNTPROC_UMNT 3
 655 #define MOUNTPROC_UMNTALL 4
 656 #define MOUNTPROC_EXPORT 5
 657 #define MOUNTPROC_EXPORTALL 6
 658
 659 #define MOUNTVERS_POSIX 2
 660
 661 #define MOUNTPROC_PATHCONF 7
 662
 663 #define MOUNT_V3 3
 664
 665 #define MOUNTPROC3_NULL 0
 666 #define MOUNTPROC3_MNT 1
 667 #define MOUNTPROC3_DUMP 2
 668 #define MOUNTPROC3_UMNT 3
 669 #define MOUNTPROC3_UMNTALL 4
 670 #define MOUNTPROC3_EXPORT 5
 671
 672 enum {
 673 #ifndef NFS_FHSIZE
 674         NFS_FHSIZE = 32,
 675 #endif
 676 #ifndef NFS_PORT
 677         NFS_PORT = 2049
 678 #endif
 679 };
 680
 681 /*
 682  * We want to be able to compile mount on old kernels in such a way
 683  * that the binary will work well on more recent kernels.
 684  * Thus, if necessary we teach nfsmount.c the structure of new fields
 685  * that will come later.
 686  *
 687  * Moreover, the new kernel includes conflict with glibc includes
 688  * so it is easiest to ignore the kernel altogether (at compile time).
 689  */
 690
 691 struct nfs2_fh {
 692         char                    data[32];
 693 };
 694 struct nfs3_fh {
 695         unsigned short          size;
 696         unsigned char           data[64];
 697 };
 698
 699 struct nfs_mount_data {
 700         int             version;                /* 1 */
 701         int             fd;                     /* 1 */
 702         struct nfs2_fh  old_root;               /* 1 */
 703         int             flags;                  /* 1 */
 704         int             rsize;                  /* 1 */
 705         int             wsize;                  /* 1 */
 706         int             timeo;                  /* 1 */
 707         int             retrans;                /* 1 */
 708         int             acregmin;               /* 1 */
 709         int             acregmax;               /* 1 */
 710         int             acdirmin;               /* 1 */
 711         int             acdirmax;               /* 1 */
 712         struct sockaddr_in addr;                /* 1 */
 713         char            hostname[256];          /* 1 */
 714         int             namlen;                 /* 2 */
 715         unsigned int    bsize;                  /* 3 */
 716         struct nfs3_fh  root;                   /* 4 */
 717 };
 718
 719 /* bits in the flags field */
 720 enum {
 721         NFS_MOUNT_SOFT = 0x0001,        /* 1 */
 722         NFS_MOUNT_INTR = 0x0002,        /* 1 */
 723         NFS_MOUNT_SECURE = 0x0004,      /* 1 */
 724         NFS_MOUNT_POSIX = 0x0008,       /* 1 */
 725         NFS_MOUNT_NOCTO = 0x0010,       /* 1 */
 726         NFS_MOUNT_NOAC = 0x0020,        /* 1 */
 727         NFS_MOUNT_TCP = 0x0040,         /* 2 */
 728         NFS_MOUNT_VER3 = 0x0080,        /* 3 */
 729         NFS_MOUNT_KERBEROS = 0x0100,    /* 3 */
 730         NFS_MOUNT_NONLM = 0x0200,       /* 3 */
 731         NFS_MOUNT_NORDIRPLUS = 0x4000
 732 };
 733
 734
 735 /*
 736  * We need to translate between nfs status return values and
 737  * the local errno values which may not be the same.
 738  *
 739  * Andreas Schwab <schwab@LS5.informatik.uni-dortmund.de>: change errno:
 740  * "after #include <errno.h> the symbol errno is reserved for any use,
 741  *  it cannot even be used as a struct tag or field name".
 742  */
 743 #ifndef EDQUOT
 744 # define EDQUOT ENOSPC
 745 #endif
 746 /* Convert each NFSERR_BLAH into EBLAH */
 747 static const uint8_t nfs_err_stat[] = {
 748          1,  2,  5,  6, 13, 17,
 749         19, 20, 21, 22, 27, 28,
 750         30, 63, 66, 69, 70, 71
 751 };
 752 static const uint8_t nfs_err_errnum[] = {
 753         EPERM , ENOENT      , EIO      , ENXIO , EACCES, EEXIST,
 754         ENODEV, ENOTDIR     , EISDIR   , EINVAL, EFBIG , ENOSPC,
 755         EROFS , ENAMETOOLONG, ENOTEMPTY, EDQUOT, ESTALE, EREMOTE
 756 };
 757 static char *nfs_strerror(int status)
 758 {
 759         int i;
 760
 761         for (i = 0; i < ARRAY_SIZE(nfs_err_stat); i++) {
 762                 if (nfs_err_stat[i] == status)
 763                         return strerror(nfs_err_errnum[i]);
 764         }
 765         return xasprintf("unknown nfs status return value: %d", status);
 766 }
 767
 768 static bool_t xdr_fhandle(XDR *xdrs, fhandle objp)
 769 {
 770         if (!xdr_opaque(xdrs, objp, FHSIZE))
 771                  return FALSE;
 772         return TRUE;
 773 }
 774
 775 static bool_t xdr_fhstatus(XDR *xdrs, fhstatus *objp)
 776 {
 777         if (!xdr_u_int(xdrs, &objp->fhs_status))
 778                  return FALSE;
 779         switch (objp->fhs_status) {
 780         case 0:
 781                 if (!xdr_fhandle(xdrs, objp->fhstatus_u.fhs_fhandle))
 782                          return FALSE;
 783                 break;
 784         default:
 785                 break;
 786         }
 787         return TRUE;
 788 }
 789
 790 static bool_t xdr_dirpath(XDR *xdrs, dirpath *objp)
 791 {
 792         if (!xdr_string(xdrs, objp, MNTPATHLEN))
 793                  return FALSE;
 794         return TRUE;
 795 }
 796
 797 static bool_t xdr_fhandle3(XDR *xdrs, fhandle3 *objp)
 798 {
 799         if (!xdr_bytes(xdrs, (char **)&objp->fhandle3_val,
 800                                 (unsigned int *) &objp->fhandle3_len,
 801                                 FHSIZE3)
 802         ) {
 803                  return FALSE;
 804         }
 805         return TRUE;
 806 }
 807
 808 static bool_t xdr_mountres3_ok(XDR *xdrs, mountres3_ok *objp)
 809 {
 810         if (!xdr_fhandle3(xdrs, &objp->fhandle))
 811                 return FALSE;
 812         if (!xdr_array(xdrs, &(objp->auth_flavours.auth_flavours_val),
 813                                 &(objp->auth_flavours.auth_flavours_len),
 814                                 ~0,
 815                                 sizeof(int),
 816                                 (xdrproc_t) xdr_int)
 817         ) {
 818                 return FALSE;
 819         }
 820         return TRUE;
 821 }
 822
 823 static bool_t xdr_mountstat3(XDR *xdrs, mountstat3 *objp)
 824 {
 825         if (!xdr_enum(xdrs, (enum_t *) objp))
 826                  return FALSE;
 827         return TRUE;
 828 }
 829
 830 static bool_t xdr_mountres3(XDR *xdrs, mountres3 *objp)
 831 {
 832         if (!xdr_mountstat3(xdrs, &objp->fhs_status))
 833                 return FALSE;
 834         switch (objp->fhs_status) {
 835         case MNT_OK:
 836                 if (!xdr_mountres3_ok(xdrs, &objp->mountres3_u.mountinfo))
 837                          return FALSE;
 838                 break;
 839         default:
 840                 break;
 841         }
 842         return TRUE;
 843 }
 844
 845 #define MAX_NFSPROT ((nfs_mount_version >= 4) ? 3 : 2)
 846
 847 /*
 848  * Unfortunately, the kernel prints annoying console messages
 849  * in case of an unexpected nfs mount version (instead of
 850  * just returning some error).  Therefore we'll have to try
 851  * and figure out what version the kernel expects.
 852  *
 853  * Variables:
 854  *      KERNEL_NFS_MOUNT_VERSION: kernel sources at compile time
 855  *      NFS_MOUNT_VERSION: these nfsmount sources at compile time
 856  *      nfs_mount_version: version this source and running kernel can handle
 857  */
 858 static void
 859 find_kernel_nfs_mount_version(void)
 860 {
 861         int kernel_version;
 862
 863         if (nfs_mount_version)
 864                 return;
 865
 866         nfs_mount_version = 4; /* default */
 867
 868         kernel_version = get_linux_version_code();
 869         if (kernel_version) {
 870                 if (kernel_version < KERNEL_VERSION(2,2,18))
 871                         nfs_mount_version = 3;
 872                 /* else v4 since 2.3.99pre4 */
 873         }
 874 }
 875
 876 static void
 877 get_mountport(struct pmap *pm_mnt,
 878         struct sockaddr_in *server_addr,
 879         long unsigned prog,
 880         long unsigned version,
 881         long unsigned proto,
 882         long unsigned port)
 883 {
 884         struct pmaplist *pmap;
 885
 886         server_addr->sin_port = PMAPPORT;
 887 /* glibc 2.4 (still) has pmap_getmaps(struct sockaddr_in *).
 888  * I understand it like "IPv6 for this is not 100% ready" */
 889         pmap = pmap_getmaps(server_addr);
 890
 891         if (version > MAX_NFSPROT)
 892                 version = MAX_NFSPROT;
 893         if (!prog)
 894                 prog = MOUNTPROG;
 895         pm_mnt->pm_prog = prog;
 896         pm_mnt->pm_vers = version;
 897         pm_mnt->pm_prot = proto;
 898         pm_mnt->pm_port = port;
 899
 900         while (pmap) {
 901                 if (pmap->pml_map.pm_prog != prog)
 902                         goto next;
 903                 if (!version && pm_mnt->pm_vers > pmap->pml_map.pm_vers)
 904                         goto next;
 905                 if (version > 2 && pmap->pml_map.pm_vers != version)
 906                         goto next;
 907                 if (version && version <= 2 && pmap->pml_map.pm_vers > 2)
 908                         goto next;
 909                 if (pmap->pml_map.pm_vers > MAX_NFSPROT
 910                  || (proto && pm_mnt->pm_prot && pmap->pml_map.pm_prot != proto)
 911                  || (port && pmap->pml_map.pm_port != port)
 912                 ) {
 913                         goto next;
 914                 }
 915                 memcpy(pm_mnt, &pmap->pml_map, sizeof(*pm_mnt));
 916  next:
 917                 pmap = pmap->pml_next;
 918         }
 919         if (!pm_mnt->pm_vers)
 920                 pm_mnt->pm_vers = MOUNTVERS;
 921         if (!pm_mnt->pm_port)
 922                 pm_mnt->pm_port = MOUNTPORT;
 923         if (!pm_mnt->pm_prot)
 924                 pm_mnt->pm_prot = IPPROTO_TCP;
 925 }
 926
 927 #if BB_MMU
 928 static int daemonize(void)
 929 {
 930         int pid = fork();
 931         if (pid < 0) /* error */
 932                 return -errno;
 933         if (pid > 0) /* parent */
 934                 return 0;
 935         /* child */
 936         close(0);
 937         xopen(bb_dev_null, O_RDWR);
 938         xdup2(0, 1);
 939         xdup2(0, 2);
 940         setsid();
 941         openlog(applet_name, LOG_PID, LOG_DAEMON);
 942         logmode = LOGMODE_SYSLOG;
 943         return 1;
 944 }
 945 #else
 946 static inline int daemonize(void) { return -ENOSYS; }
 947 #endif
 948
 949 /* TODO */
 950 static inline int we_saw_this_host_before(const char *hostname UNUSED_PARAM)
 951 {
 952         return 0;
 953 }
 954
 955 /* RPC strerror analogs are terminally idiotic:
 956  * *mandatory* prefix and \n at end.
 957  * This hopefully helps. Usage:
 958  * error_msg_rpc(clnt_*error*(" ")) */
 959 static void error_msg_rpc(const char *msg)
 960 {
 961         int len;
 962         while (msg[0] == ' ' || msg[0] == ':') msg++;
 963         len = strlen(msg);
 964         while (len && msg[len-1] == '\n') len--;
 965         bb_error_msg("%.*s", len, msg);
 966 }
 967
 968 /* NB: mp->xxx fields may be trashed on exit */
 969 static NOINLINE int nfsmount(struct mntent *mp, long vfsflags, char *filteropts)
 970 {
 971         CLIENT *mclient;
 972         char *hostname;
 973         char *pathname;
 974         char *mounthost;
 975         /* prior to 2.6.23, kernel took NFS options in a form of this struct
 976          * only. 2.6.23+ looks at data->version, and if it's not 1..6,
 977          * then data pointer is interpreted as a string. */
 978         struct nfs_mount_data data;
 979         char *opt;
 980         struct hostent *hp;
 981         struct sockaddr_in server_addr;
 982         struct sockaddr_in mount_server_addr;
 983         int msock, fsock;
 984         union {
 985                 struct fhstatus nfsv2;
 986                 struct mountres3 nfsv3;
 987         } status;
 988         int daemonized;
 989         char *s;
 990         int port;
 991         int mountport;
 992         int proto;
 993 #if BB_MMU
 994         smallint bg = 0;
 995 #else
 996         enum { bg = 0 };
 997 #endif
 998         int retry;
 999         int mountprog;
1000         int mountvers;
1001         int nfsprog;
1002         int nfsvers;
1003         int retval;
1004         /* these all are one-bit really. gcc 4.3.1 likes this combination: */
1005         smallint tcp;
1006         smallint soft;
1007         int intr;
1008         int posix;
1009         int nocto;
1010         int noac;
1011         int nordirplus;
1012         int nolock;
1013
1014         find_kernel_nfs_mount_version();
1015
1016         daemonized = 0;
1017         mounthost = NULL;
1018         retval = ETIMEDOUT;
1019         msock = fsock = -1;
1020         mclient = NULL;
1021
1022         /* NB: hostname, mounthost, filteropts must be free()d prior to return */
1023
1024         filteropts = xstrdup(filteropts); /* going to trash it later... */
1025
1026         hostname = xstrdup(mp->mnt_fsname);
1027         /* mount_main() guarantees that ':' is there */
1028         s = strchr(hostname, ':');
1029         pathname = s + 1;
1030         *s = '\0';
1031         /* Ignore all but first hostname in replicated mounts
1032            until they can be fully supported. (mack@sgi.com) */
1033         s = strchr(hostname, ',');
1034         if (s) {
1035                 *s = '\0';
1036                 bb_error_msg("warning: multiple hostnames not supported");
1037         }
1038
1039         server_addr.sin_family = AF_INET;
1040         if (!inet_aton(hostname, &server_addr.sin_addr)) {
1041                 hp = gethostbyname(hostname);
1042                 if (hp == NULL) {
1043                         bb_herror_msg("%s", hostname);
1044                         goto fail;
1045                 }
1046                 if (hp->h_length != (int)sizeof(struct in_addr)) {
1047                         bb_error_msg_and_die("only IPv4 is supported");
1048                 }
1049                 memcpy(&server_addr.sin_addr, hp->h_addr_list[0], sizeof(struct in_addr));
1050         }
1051
1052         memcpy(&mount_server_addr, &server_addr, sizeof(mount_server_addr));
1053
1054         /* add IP address to mtab options for use when unmounting */
1055
1056         if (!mp->mnt_opts) { /* TODO: actually mp->mnt_opts is never NULL */
1057                 mp->mnt_opts = xasprintf("addr=%s", inet_ntoa(server_addr.sin_addr));
1058         } else {
1059                 char *tmp = xasprintf("%s%saddr=%s", mp->mnt_opts,
1060                                         mp->mnt_opts[0] ? "," : "",
1061                                         inet_ntoa(server_addr.sin_addr));
1062                 free(mp->mnt_opts);
1063                 mp->mnt_opts = tmp;
1064         }
1065
1066         /* Set default options.
1067          * rsize/wsize (and bsize, for ver >= 3) are left 0 in order to
1068          * let the kernel decide.
1069          * timeo is filled in after we know whether it'll be TCP or UDP. */
1070         memset(&data, 0, sizeof(data));
1071         data.retrans  = 3;
1072         data.acregmin = 3;
1073         data.acregmax = 60;
1074         data.acdirmin = 30;
1075         data.acdirmax = 60;
1076         data.namlen   = NAME_MAX;
1077
1078         soft = 0;
1079         intr = 0;
1080         posix = 0;
1081         nocto = 0;
1082         nolock = 0;
1083         noac = 0;
1084         nordirplus = 0;
1085         retry = 10000;          /* 10000 minutes ~ 1 week */
1086         tcp = 0;
1087
1088         mountprog = MOUNTPROG;
1089         mountvers = 0;
1090         port = 0;
1091         mountport = 0;
1092         nfsprog = 100003;
1093         nfsvers = 0;
1094
1095         /* parse options */
1096         if (filteropts) for (opt = strtok(filteropts, ","); opt; opt = strtok(NULL, ",")) {
1097                 char *opteq = strchr(opt, '=');
1098                 if (opteq) {
1099                         int val, idx;
1100                         static const char options[] ALIGN1 =
1101                                 /* 0 */ "rsize\0"
1102                                 /* 1 */ "wsize\0"
1103                                 /* 2 */ "timeo\0"
1104                                 /* 3 */ "retrans\0"
1105                                 /* 4 */ "acregmin\0"
1106                                 /* 5 */ "acregmax\0"
1107                                 /* 6 */ "acdirmin\0"
1108                                 /* 7 */ "acdirmax\0"
1109                                 /* 8 */ "actimeo\0"
1110                                 /* 9 */ "retry\0"
1111                                 /* 10 */ "port\0"
1112                                 /* 11 */ "mountport\0"
1113                                 /* 12 */ "mounthost\0"
1114                                 /* 13 */ "mountprog\0"
1115                                 /* 14 */ "mountvers\0"
1116                                 /* 15 */ "nfsprog\0"
1117                                 /* 16 */ "nfsvers\0"
1118                                 /* 17 */ "vers\0"
1119                                 /* 18 */ "proto\0"
1120                                 /* 19 */ "namlen\0"
1121                                 /* 20 */ "addr\0";
1122
1123                         *opteq++ = '\0';
1124                         idx = index_in_strings(options, opt);
1125                         switch (idx) {
1126                         case 12: // "mounthost"
1127                                 mounthost = xstrndup(opteq,
1128                                                 strcspn(opteq, " \t\n\r,"));
1129                                 continue;
1130                         case 18: // "proto"
1131                                 if (!strncmp(opteq, "tcp", 3))
1132                                         tcp = 1;
1133                                 else if (!strncmp(opteq, "udp", 3))
1134                                         tcp = 0;
1135                                 else
1136                                         bb_error_msg("warning: unrecognized proto= option");
1137                                 continue;
1138                         case 20: // "addr" - ignore
1139                                 continue;
1140                         }
1141
1142                         val = xatoi_u(opteq);
1143                         switch (idx) {
1144                         case 0: // "rsize"
1145                                 data.rsize = val;
1146                                 continue;
1147                         case 1: // "wsize"
1148                                 data.wsize = val;
1149                                 continue;
1150                         case 2: // "timeo"
1151                                 data.timeo = val;
1152                                 continue;
1153                         case 3: // "retrans"
1154                                 data.retrans = val;
1155                                 continue;
1156                         case 4: // "acregmin"
1157                                 data.acregmin = val;
1158                                 continue;
1159                         case 5: // "acregmax"
1160                                 data.acregmax = val;
1161                                 continue;
1162                         case 6: // "acdirmin"
1163                                 data.acdirmin = val;
1164                                 continue;
1165                         case 7: // "acdirmax"
1166                                 data.acdirmax = val;
1167                                 continue;
1168                         case 8: // "actimeo"
1169                                 data.acregmin = val;
1170                                 data.acregmax = val;
1171                                 data.acdirmin = val;
1172                                 data.acdirmax = val;
1173                                 continue;
1174                         case 9: // "retry"
1175                                 retry = val;
1176                                 continue;
1177                         case 10: // "port"
1178                                 port = val;
1179                                 continue;
1180                         case 11: // "mountport"
1181                                 mountport = val;
1182                                 continue;
1183                         case 13: // "mountprog"
1184                                 mountprog = val;
1185                                 continue;
1186                         case 14: // "mountvers"
1187                                 mountvers = val;
1188                                 continue;
1189                         case 15: // "nfsprog"
1190                                 nfsprog = val;
1191                                 continue;
1192                         case 16: // "nfsvers"
1193                         case 17: // "vers"
1194                                 nfsvers = val;
1195                                 continue;
1196                         case 19: // "namlen"
1197                                 //if (nfs_mount_version >= 2)
1198                                         data.namlen = val;
1199                                 //else
1200                                 //      bb_error_msg("warning: option namlen is not supported\n");
1201                                 continue;
1202                         default:
1203                                 bb_error_msg("unknown nfs mount parameter: %s=%d", opt, val);
1204                                 goto fail;
1205                         }
1206                 }
1207                 else { /* not of the form opt=val */
1208                         static const char options[] ALIGN1 =
1209                                 "bg\0"
1210                                 "fg\0"
1211                                 "soft\0"
1212                                 "hard\0"
1213                                 "intr\0"
1214                                 "posix\0"
1215                                 "cto\0"
1216                                 "ac\0"
1217                                 "tcp\0"
1218                                 "udp\0"
1219                                 "lock\0"
1220                                 "rdirplus\0";
1221                         int val = 1;
1222                         if (!strncmp(opt, "no", 2)) {
1223                                 val = 0;
1224                                 opt += 2;
1225                         }
1226                         switch (index_in_strings(options, opt)) {
1227                         case 0: // "bg"
1228 #if BB_MMU
1229                                 bg = val;
1230 #endif
1231                                 break;
1232                         case 1: // "fg"
1233 #if BB_MMU
1234                                 bg = !val;
1235 #endif
1236                                 break;
1237                         case 2: // "soft"
1238                                 soft = val;
1239                                 break;
1240                         case 3: // "hard"
1241                                 soft = !val;
1242                                 break;
1243                         case 4: // "intr"
1244                                 intr = val;
1245                                 break;
1246                         case 5: // "posix"
1247                                 posix = val;
1248                                 break;
1249                         case 6: // "cto"
1250                                 nocto = !val;
1251                                 break;
1252                         case 7: // "ac"
1253                                 noac = !val;
1254                                 break;
1255                         case 8: // "tcp"
1256                                 tcp = val;
1257                                 break;
1258                         case 9: // "udp"
1259                                 tcp = !val;
1260                                 break;
1261                         case 10: // "lock"
1262                                 if (nfs_mount_version >= 3)
1263                                         nolock = !val;
1264                                 else
1265                                         bb_error_msg("warning: option nolock is not supported");
1266                                 break;
1267                         case 11: //rdirplus
1268                                 nordirplus = !val;
1269                                 break;
1270                         default:
1271                                 bb_error_msg("unknown nfs mount option: %s%s", val ? "" : "no", opt);
1272                                 goto fail;
1273                         }
1274                 }
1275         }
1276         proto = (tcp) ? IPPROTO_TCP : IPPROTO_UDP;
1277
1278         data.flags = (soft ? NFS_MOUNT_SOFT : 0)
1279                 | (intr ? NFS_MOUNT_INTR : 0)
1280                 | (posix ? NFS_MOUNT_POSIX : 0)
1281                 | (nocto ? NFS_MOUNT_NOCTO : 0)
1282                 | (noac ? NFS_MOUNT_NOAC : 0)
1283                 | (nordirplus ? NFS_MOUNT_NORDIRPLUS : 0);
1284         if (nfs_mount_version >= 2)
1285                 data.flags |= (tcp ? NFS_MOUNT_TCP : 0);
1286         if (nfs_mount_version >= 3)
1287                 data.flags |= (nolock ? NFS_MOUNT_NONLM : 0);
1288         if (nfsvers > MAX_NFSPROT || mountvers > MAX_NFSPROT) {
1289                 bb_error_msg("NFSv%d not supported", nfsvers);
1290                 goto fail;
1291         }
1292         if (nfsvers && !mountvers)
1293                 mountvers = (nfsvers < 3) ? 1 : nfsvers;
1294         if (nfsvers && nfsvers < mountvers) {
1295                 mountvers = nfsvers;
1296         }
1297
1298         /* Adjust options if none specified */
1299         if (!data.timeo)
1300                 data.timeo = tcp ? 70 : 7;
1301
1302         data.version = nfs_mount_version;
1303
1304         if (vfsflags & MS_REMOUNT)
1305                 goto do_mount;
1306
1307         /*
1308          * If the previous mount operation on the same host was
1309          * backgrounded, and the "bg" for this mount is also set,
1310          * give up immediately, to avoid the initial timeout.
1311          */
1312         if (bg && we_saw_this_host_before(hostname)) {
1313                 daemonized = daemonize();
1314                 if (daemonized <= 0) { /* parent or error */
1315                         retval = -daemonized;
1316                         goto ret;
1317                 }
1318         }
1319
1320         /* Create mount daemon client */
1321         /* See if the nfs host = mount host. */
1322         if (mounthost) {
1323                 if (mounthost[0] >= '0' && mounthost[0] <= '9') {
1324                         mount_server_addr.sin_family = AF_INET;
1325                         mount_server_addr.sin_addr.s_addr = inet_addr(hostname);
1326                 } else {
1327                         hp = gethostbyname(mounthost);
1328                         if (hp == NULL) {
1329                                 bb_herror_msg("%s", mounthost);
1330                                 goto fail;
1331                         }
1332                         if (hp->h_length != (int)sizeof(struct in_addr)) {
1333                                 bb_error_msg_and_die("only IPv4 is supported");
1334                         }
1335                         mount_server_addr.sin_family = AF_INET;
1336                         memcpy(&mount_server_addr.sin_addr, hp->h_addr_list[0], sizeof(struct in_addr));
1337                 }
1338         }
1339
1340         /*
1341          * The following loop implements the mount retries. When the mount
1342          * times out, and the "bg" option is set, we background ourself
1343          * and continue trying.
1344          *
1345          * The case where the mount point is not present and the "bg"
1346          * option is set, is treated as a timeout. This is done to
1347          * support nested mounts.
1348          *
1349          * The "retry" count specified by the user is the number of
1350          * minutes to retry before giving up.
1351          */
1352         {
1353                 struct timeval total_timeout;
1354                 struct timeval retry_timeout;
1355                 struct pmap pm_mnt;
1356                 time_t t;
1357                 time_t prevt;
1358                 time_t timeout;
1359
1360                 retry_timeout.tv_sec = 3;
1361                 retry_timeout.tv_usec = 0;
1362                 total_timeout.tv_sec = 20;
1363                 total_timeout.tv_usec = 0;
1364 /* FIXME: use monotonic()? */
1365                 timeout = time(NULL) + 60 * retry;
1366                 prevt = 0;
1367                 t = 30;
1368  retry:
1369                 /* Be careful not to use too many CPU cycles */
1370                 if (t - prevt < 30)
1371                         sleep(30);
1372
1373                 get_mountport(&pm_mnt, &mount_server_addr,
1374                                 mountprog,
1375                                 mountvers,
1376                                 proto,
1377                                 mountport);
1378                 nfsvers = (pm_mnt.pm_vers < 2) ? 2 : pm_mnt.pm_vers;
1379
1380                 /* contact the mount daemon via TCP */
1381                 mount_server_addr.sin_port = htons(pm_mnt.pm_port);
1382                 msock = RPC_ANYSOCK;
1383
1384                 switch (pm_mnt.pm_prot) {
1385                 case IPPROTO_UDP:
1386                         mclient = clntudp_create(&mount_server_addr,
1387                                                  pm_mnt.pm_prog,
1388                                                  pm_mnt.pm_vers,
1389                                                  retry_timeout,
1390                                                  &msock);
1391                         if (mclient)
1392                                 break;
1393                         mount_server_addr.sin_port = htons(pm_mnt.pm_port);
1394                         msock = RPC_ANYSOCK;
1395                 case IPPROTO_TCP:
1396                         mclient = clnttcp_create(&mount_server_addr,
1397                                                  pm_mnt.pm_prog,
1398                                                  pm_mnt.pm_vers,
1399                                                  &msock, 0, 0);
1400                         break;
1401                 default:
1402                         mclient = NULL;
1403                 }
1404                 if (!mclient) {
1405                         if (!daemonized && prevt == 0)
1406                                 error_msg_rpc(clnt_spcreateerror(" "));
1407                 } else {
1408                         enum clnt_stat clnt_stat;
1409
1410                         /* Try to mount hostname:pathname */
1411                         mclient->cl_auth = authunix_create_default();
1412
1413                         /* Make pointers in xdr_mountres3 NULL so
1414                          * that xdr_array allocates memory for us
1415                          */
1416                         memset(&status, 0, sizeof(status));
1417
1418                         if (pm_mnt.pm_vers == 3)
1419                                 clnt_stat = clnt_call(mclient, MOUNTPROC3_MNT,
1420                                               (xdrproc_t) xdr_dirpath,
1421                                               (caddr_t) &pathname,
1422                                               (xdrproc_t) xdr_mountres3,
1423                                               (caddr_t) &status,
1424                                               total_timeout);
1425                         else
1426                                 clnt_stat = clnt_call(mclient, MOUNTPROC_MNT,
1427                                               (xdrproc_t) xdr_dirpath,
1428                                               (caddr_t) &pathname,
1429                                               (xdrproc_t) xdr_fhstatus,
1430                                               (caddr_t) &status,
1431                                               total_timeout);
1432
1433                         if (clnt_stat == RPC_SUCCESS)
1434                                 goto prepare_kernel_data; /* we're done */
1435                         if (errno != ECONNREFUSED) {
1436                                 error_msg_rpc(clnt_sperror(mclient, " "));
1437                                 goto fail;      /* don't retry */
1438                         }
1439                         /* Connection refused */
1440                         if (!daemonized && prevt == 0) /* print just once */
1441                                 error_msg_rpc(clnt_sperror(mclient, " "));
1442                         auth_destroy(mclient->cl_auth);
1443                         clnt_destroy(mclient);
1444                         mclient = NULL;
1445                         close(msock);
1446                         msock = -1;
1447                 }
1448
1449                 /* Timeout. We are going to retry... maybe */
1450                 if (!bg)
1451                         goto fail;
1452                 if (!daemonized) {
1453                         daemonized = daemonize();
1454                         if (daemonized <= 0) { /* parent or error */
1455                                 retval = -daemonized;
1456                                 goto ret;
1457                         }
1458                 }
1459                 prevt = t;
1460                 t = time(NULL);
1461                 if (t >= timeout)
1462                         /* TODO error message */
1463                         goto fail;
1464
1465                 goto retry;
1466         }
1467
1468  prepare_kernel_data:
1469
1470         if (nfsvers == 2) {
1471                 if (status.nfsv2.fhs_status != 0) {
1472                         bb_error_msg("%s:%s failed, reason given by server: %s",
1473                                 hostname, pathname,
1474                                 nfs_strerror(status.nfsv2.fhs_status));
1475                         goto fail;
1476                 }
1477                 memcpy(data.root.data,
1478                                 (char *) status.nfsv2.fhstatus_u.fhs_fhandle,
1479                                 NFS_FHSIZE);
1480                 data.root.size = NFS_FHSIZE;
1481                 memcpy(data.old_root.data,
1482                                 (char *) status.nfsv2.fhstatus_u.fhs_fhandle,
1483                                 NFS_FHSIZE);
1484         } else {
1485                 fhandle3 *my_fhandle;
1486                 if (status.nfsv3.fhs_status != 0) {
1487                         bb_error_msg("%s:%s failed, reason given by server: %s",
1488                                 hostname, pathname,
1489                                 nfs_strerror(status.nfsv3.fhs_status));
1490                         goto fail;
1491                 }
1492                 my_fhandle = &status.nfsv3.mountres3_u.mountinfo.fhandle;
1493                 memset(data.old_root.data, 0, NFS_FHSIZE);
1494                 memset(&data.root, 0, sizeof(data.root));
1495                 data.root.size = my_fhandle->fhandle3_len;
1496                 memcpy(data.root.data,
1497                                 (char *) my_fhandle->fhandle3_val,
1498                                 my_fhandle->fhandle3_len);
1499
1500                 data.flags |= NFS_MOUNT_VER3;
1501         }
1502
1503         /* Create nfs socket for kernel */
1504         if (tcp) {
1505                 if (nfs_mount_version < 3) {
1506                         bb_error_msg("NFS over TCP is not supported");
1507                         goto fail;
1508                 }
1509                 fsock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
1510         } else
1511                 fsock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
1512         if (fsock < 0) {
1513                 bb_perror_msg("nfs socket");
1514                 goto fail;
1515         }
1516         if (bindresvport(fsock, 0) < 0) {
1517                 bb_perror_msg("nfs bindresvport");
1518                 goto fail;
1519         }
1520         if (port == 0) {
1521                 server_addr.sin_port = PMAPPORT;
1522                 port = pmap_getport(&server_addr, nfsprog, nfsvers,
1523                                         tcp ? IPPROTO_TCP : IPPROTO_UDP);
1524                 if (port == 0)
1525                         port = NFS_PORT;
1526         }
1527         server_addr.sin_port = htons(port);
1528
1529         /* Prepare data structure for kernel */
1530         data.fd = fsock;
1531         memcpy((char *) &data.addr, (char *) &server_addr, sizeof(data.addr));
1532         strncpy(data.hostname, hostname, sizeof(data.hostname));
1533
1534         /* Clean up */
1535         auth_destroy(mclient->cl_auth);
1536         clnt_destroy(mclient);
1537         close(msock);
1538         msock = -1;
1539
1540         if (bg) {
1541                 /* We must wait until mount directory is available */
1542                 struct stat statbuf;
1543                 int delay = 1;
1544                 while (stat(mp->mnt_dir, &statbuf) == -1) {
1545                         if (!daemonized) {
1546                                 daemonized = daemonize();
1547                                 if (daemonized <= 0) { /* parent or error */
1548 /* FIXME: parent doesn't close fsock - ??! */
1549                                         retval = -daemonized;
1550                                         goto ret;
1551                                 }
1552                         }
1553                         sleep(delay);   /* 1, 2, 4, 8, 16, 30, ... */
1554                         delay *= 2;
1555                         if (delay > 30)
1556                                 delay = 30;
1557                 }
1558         }
1559
1560         /* Perform actual mount */
1561  do_mount:
1562         mp->mnt_type = (char*)"nfs";
1563         retval = mount_it_now(mp, vfsflags, (char*)&data);
1564         goto ret;
1565
1566         /* Abort */
1567  fail:
1568         if (msock >= 0) {
1569                 if (mclient) {
1570                         auth_destroy(mclient->cl_auth);
1571                         clnt_destroy(mclient);
1572                 }
1573                 close(msock);
1574         }
1575         if (fsock >= 0)
1576                 close(fsock);
1577
1578  ret:
1579         free(hostname);
1580         free(mounthost);
1581         free(filteropts);
1582         return retval;
1583 }
1584
1585 #else // !ENABLE_FEATURE_MOUNT_NFS
1586
1587 // Never called. Call should be optimized out.
1588 int nfsmount(struct mntent *mp, long vfsflags, char *filteropts);
1589
1590 #endif // !ENABLE_FEATURE_MOUNT_NFS
1591
1592 // Mount one directory.  Handles CIFS, NFS, loopback, autobind, and filesystem
1593 // type detection.  Returns 0 for success, nonzero for failure.
1594 // NB: mp->xxx fields may be trashed on exit
1595 static int singlemount(struct mntent *mp, int ignore_busy)
1596 {
1597         int rc = -1;
1598         long vfsflags;
1599         char *loopFile = NULL, *filteropts = NULL;
1600         llist_t *fl = NULL;
1601         struct stat st;
1602
1603         errno = 0;
1604
1605         vfsflags = parse_mount_options(mp->mnt_opts, &filteropts);
1606
1607         // Treat fstype "auto" as unspecified
1608         if (mp->mnt_type && strcmp(mp->mnt_type, "auto") == 0)
1609                 mp->mnt_type = NULL;
1610
1611         // Might this be a virtual filesystem?
1612         if (ENABLE_FEATURE_MOUNT_HELPERS && strchr(mp->mnt_fsname, '#')) {
1613                 char *args[35];
1614                 char *s;
1615                 int n;
1616                 // fsname: "cmd#arg1#arg2..."
1617                 // WARNING: allows execution of arbitrary commands!
1618                 // Try "mount 'sh#-c#sh' bogus_dir".
1619                 // It is safe ONLY because non-root
1620                 // cannot use two-argument mount command
1621                 // and using one-argument "mount 'sh#-c#sh'" doesn't work:
1622                 // "mount: can't find sh#-c#sh in /etc/fstab"
1623                 // (if /etc/fstab has it, it's ok: root sets up /etc/fstab).
1624
1625                 s = mp->mnt_fsname;
1626                 n = 0;
1627                 args[n++] = s;
1628                 while (*s && n < 35 - 2) {
1629                         if (*s++ == '#' && *s != '#') {
1630                                 s[-1] = '\0';
1631                                 args[n++] = s;
1632                         }
1633                 }
1634                 args[n++] = mp->mnt_dir;
1635                 args[n] = NULL;
1636                 rc = wait4pid(xspawn(args));
1637                 goto report_error;
1638         }
1639
1640         // Might this be an CIFS filesystem?
1641         if (ENABLE_FEATURE_MOUNT_CIFS
1642          && (!mp->mnt_type || strcmp(mp->mnt_type, "cifs") == 0)
1643          && (mp->mnt_fsname[0] == '/' || mp->mnt_fsname[0] == '\\')
1644          && mp->mnt_fsname[0] == mp->mnt_fsname[1]
1645         ) {
1646                 int len;
1647                 char c;
1648                 len_and_sockaddr *lsa;
1649                 char *hostname, *dotted, *ip;
1650
1651                 hostname = mp->mnt_fsname + 2;
1652                 len = strcspn(hostname, "/\\");
1653                 if (len == 0 || hostname[len] == '\0')
1654                         goto report_error;
1655                 c = hostname[len];
1656                 hostname[len] = '\0';
1657                 lsa = host2sockaddr(hostname, 0);
1658                 hostname[len] = c;
1659                 if (!lsa)
1660                         goto report_error;
1661
1662                 // Insert "ip=..." option into options
1663                 dotted = xmalloc_sockaddr2dotted_noport(&lsa->u.sa);
1664                 if (ENABLE_FEATURE_CLEAN_UP) free(lsa);
1665                 ip = xasprintf("ip=%s", dotted);
1666                 if (ENABLE_FEATURE_CLEAN_UP) free(dotted);
1667                 parse_mount_options(ip, &filteropts);
1668                 if (ENABLE_FEATURE_CLEAN_UP) free(ip);
1669
1670                 // "-o mand" is required [why?]
1671                 vfsflags |= MS_MANDLOCK;
1672                 mp->mnt_type = (char*)"cifs";
1673                 rc = mount_it_now(mp, vfsflags, filteropts);
1674
1675                 goto report_error;
1676         }
1677
1678         // Might this be an NFS filesystem?
1679         if (ENABLE_FEATURE_MOUNT_NFS
1680          && (!mp->mnt_type || strcmp(mp->mnt_type, "nfs") == 0)
1681          && strchr(mp->mnt_fsname, ':') != NULL
1682         ) {
1683                 rc = nfsmount(mp, vfsflags, filteropts);
1684                 goto report_error;
1685         }
1686
1687         // Look at the file.  (Not found isn't a failure for remount, or for
1688         // a synthetic filesystem like proc or sysfs.)
1689         // (We use stat, not lstat, in order to allow
1690         // mount symlink_to_file_or_blkdev dir)
1691         if (!stat(mp->mnt_fsname, &st)
1692          && !(vfsflags & (MS_REMOUNT | MS_BIND | MS_MOVE))
1693         ) {
1694                 // Do we need to allocate a loopback device for it?
1695                 if (ENABLE_FEATURE_MOUNT_LOOP && S_ISREG(st.st_mode)) {
1696                         loopFile = bb_simplify_path(mp->mnt_fsname);
1697                         mp->mnt_fsname = NULL; // will receive malloced loop dev name
1698                         if (set_loop(&mp->mnt_fsname, loopFile, 0) < 0) {
1699                                 if (errno == EPERM || errno == EACCES)
1700                                         bb_error_msg(bb_msg_perm_denied_are_you_root);
1701                                 else
1702                                         bb_perror_msg("can't setup loop device");
1703                                 return errno;
1704                         }
1705
1706                 // Autodetect bind mounts
1707                 } else if (S_ISDIR(st.st_mode) && !mp->mnt_type)
1708                         vfsflags |= MS_BIND;
1709         }
1710
1711         // If we know the fstype (or don't need to), jump straight
1712         // to the actual mount.
1713         if (mp->mnt_type || (vfsflags & (MS_REMOUNT | MS_BIND | MS_MOVE)))
1714                 rc = mount_it_now(mp, vfsflags, filteropts);
1715         else {
1716                 // Loop through filesystem types until mount succeeds
1717                 // or we run out
1718
1719                 // Initialize list of block backed filesystems.
1720                 // This has to be done here so that during "mount -a",
1721                 // mounts after /proc shows up can autodetect.
1722                 if (!fslist) {
1723                         fslist = get_block_backed_filesystems();
1724                         if (ENABLE_FEATURE_CLEAN_UP && fslist)
1725                                 atexit(delete_block_backed_filesystems);
1726                 }
1727
1728                 for (fl = fslist; fl; fl = fl->link) {
1729                         mp->mnt_type = fl->data;
1730                         rc = mount_it_now(mp, vfsflags, filteropts);
1731                         if (!rc)
1732                                 break;
1733                 }
1734         }
1735
1736         // If mount failed, clean up loop file (if any).
1737         if (ENABLE_FEATURE_MOUNT_LOOP && rc && loopFile) {
1738                 del_loop(mp->mnt_fsname);
1739                 if (ENABLE_FEATURE_CLEAN_UP) {
1740                         free(loopFile);
1741                         free(mp->mnt_fsname);
1742                 }
1743         }
1744
1745  report_error:
1746         if (ENABLE_FEATURE_CLEAN_UP)
1747                 free(filteropts);
1748
1749         if (errno == EBUSY && ignore_busy)
1750                 return 0;
1751         if (rc < 0)
1752                 bb_perror_msg("mounting %s on %s failed", mp->mnt_fsname, mp->mnt_dir);
1753         return rc;
1754 }
1755
1756 // -O support
1757 //    -O interprets a list of filter options which select whether a mount
1758 // point will be mounted: only mounts with options matching *all* filtering
1759 // options will be selected.
1760 //    By default each -O filter option must be present in the list of mount
1761 // options, but if it is prefixed by "no" then it must be absent.
1762 // For example,
1763 //  -O a,nob,c  matches  -o a,c  but fails to match  -o a,b,c
1764 //              (and also fails to match  -o a  because  -o c  is absent).
1765 //
1766 // It is different from -t in that each option is matched exactly; a leading
1767 // "no" at the beginning of one option does not negate the rest.
1768 static int match_opt(const char *fs_opt_in, const char *O_opt)
1769 {
1770         if (!O_opt)
1771                 return 1;
1772
1773         while (*O_opt) {
1774                 const char *fs_opt = fs_opt_in;
1775                 int O_len;
1776                 int match;
1777
1778                 // If option begins with "no" then treat as an inverted match:
1779                 // matching is a failure
1780                 match = 0;
1781                 if (O_opt[0] == 'n' && O_opt[1] == 'o') {
1782                         match = 1;
1783                         O_opt += 2;
1784                 }
1785                 // Isolate the current O option
1786                 O_len = strchrnul(O_opt, ',') - O_opt;
1787                 // Check for a match against existing options
1788                 while (1) {
1789                         if (strncmp(fs_opt, O_opt, O_len) == 0
1790                          && (fs_opt[O_len] == '\0' || fs_opt[O_len] == ',')
1791                         ) {
1792                                 if (match)
1793                                         return 0;  // "no" prefix, but option found
1794                                 match = 1;  // current O option found, go check next one
1795                                 break;
1796                         }
1797                         fs_opt = strchr(fs_opt, ',');
1798                         if (!fs_opt)
1799                                 break;
1800                         fs_opt++;
1801                 }
1802                 if (match == 0)
1803                         return 0;     // match wanted but not found
1804                 if (O_opt[O_len] == '\0') // end?
1805                         break;
1806                 // Step to the next O option
1807                 O_opt += O_len + 1;
1808         }
1809         // If we get here then everything matched
1810         return 1;
1811 }
1812
1813 // Parse options, if necessary parse fstab/mtab, and call singlemount for
1814 // each directory to be mounted.
1815 int mount_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1816 int mount_main(int argc UNUSED_PARAM, char **argv)
1817 {
1818         char *cmdopts = xzalloc(1);
1819         char *fstype = NULL;
1820         char *O_optmatch = NULL;
1821         char *storage_path;
1822         llist_t *lst_o = NULL;
1823         const char *fstabname;
1824         FILE *fstab;
1825         int i, j;
1826         int rc = EXIT_SUCCESS;
1827         unsigned opt;
1828         struct mntent mtpair[2], *mtcur = mtpair;
1829         IF_NOT_DESKTOP(const int nonroot = 0;)
1830
1831         IF_DESKTOP(int nonroot = ) sanitize_env_if_suid();
1832
1833         // Parse long options, like --bind and --move.  Note that -o option
1834         // and --option are synonymous.  Yes, this means --remount,rw works.
1835         for (i = j = 1; argv[i]; i++) {
1836                 if (argv[i][0] == '-' && argv[i][1] == '-')
1837                         append_mount_options(&cmdopts, argv[i] + 2);
1838                 else
1839                         argv[j++] = argv[i];
1840         }
1841         argv[j] = NULL;
1842
1843         // Parse remaining options
1844         // Max 2 params; -o is a list, -v is a counter
1845         opt_complementary = "?2o::" IF_FEATURE_MOUNT_VERBOSE("vv");
1846         opt = getopt32(argv, OPTION_STR, &lst_o, &fstype, &O_optmatch
1847                         IF_FEATURE_MOUNT_VERBOSE(, &verbose));
1848         while (lst_o) append_mount_options(&cmdopts, llist_pop(&lst_o)); // -o
1849         if (opt & OPT_r) append_mount_options(&cmdopts, "ro"); // -r
1850         if (opt & OPT_w) append_mount_options(&cmdopts, "rw"); // -w
1851         argv += optind;
1852
1853         // If we have no arguments, show currently mounted filesystems
1854         if (!argv[0]) {
1855                 if (!(opt & OPT_a)) {
1856                         FILE *mountTable = setmntent(bb_path_mtab_file, "r");
1857
1858                         if (!mountTable)
1859                                 bb_error_msg_and_die("no %s", bb_path_mtab_file);
1860
1861                         while (getmntent_r(mountTable, &mtpair[0], getmntent_buf,
1862                                                                 GETMNTENT_BUFSIZE))
1863                         {
1864                                 // Don't show rootfs. FIXME: why??
1865                                 // util-linux 2.12a happily shows rootfs...
1866                                 //if (strcmp(mtpair->mnt_fsname, "rootfs") == 0) continue;
1867
1868                                 if (!fstype || strcmp(mtpair->mnt_type, fstype) == 0)
1869                                         printf("%s on %s type %s (%s)\n", mtpair->mnt_fsname,
1870                                                         mtpair->mnt_dir, mtpair->mnt_type,
1871                                                         mtpair->mnt_opts);
1872                         }
1873                         if (ENABLE_FEATURE_CLEAN_UP)
1874                                 endmntent(mountTable);
1875                         return EXIT_SUCCESS;
1876                 }
1877                 storage_path = NULL;
1878         } else {
1879                 // When we have two arguments, the second is the directory and we can
1880                 // skip looking at fstab entirely.  We can always abspath() the directory
1881                 // argument when we get it.
1882                 if (argv[1]) {
1883                         if (nonroot)
1884                                 bb_error_msg_and_die(bb_msg_you_must_be_root);
1885                         mtpair->mnt_fsname = argv[0];
1886                         mtpair->mnt_dir = argv[1];
1887                         mtpair->mnt_type = fstype;
1888                         mtpair->mnt_opts = cmdopts;
1889                         resolve_mount_spec(&mtpair->mnt_fsname);
1890                         rc = singlemount(mtpair, /*ignore_busy:*/ 0);
1891                         return rc;
1892                 }
1893                 storage_path = bb_simplify_path(argv[0]); // malloced
1894         }
1895
1896         // Past this point, we are handling either "mount -a [opts]"
1897         // or "mount [opts] single_param"
1898
1899         i = parse_mount_options(cmdopts, NULL); // FIXME: should be "long", not "int"
1900         if (nonroot && (i & ~MS_SILENT)) // Non-root users cannot specify flags
1901                 bb_error_msg_and_die(bb_msg_you_must_be_root);
1902
1903         // If we have a shared subtree flag, don't worry about fstab or mtab.
1904         if (ENABLE_FEATURE_MOUNT_FLAGS
1905          && (i & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
1906         ) {
1907                 // verbose_mount(source, target, type, flags, data)
1908                 rc = verbose_mount("", argv[0], "", i, "");
1909                 if (rc)
1910                         bb_simple_perror_msg_and_die(argv[0]);
1911                 return rc;
1912         }
1913
1914         // Open either fstab or mtab
1915         fstabname = "/etc/fstab";
1916         if (i & MS_REMOUNT) {
1917                 // WARNING. I am not sure this matches util-linux's
1918                 // behavior. It's possible util-linux does not
1919                 // take -o opts from mtab (takes only mount source).
1920                 fstabname = bb_path_mtab_file;
1921         }
1922         fstab = setmntent(fstabname, "r");
1923         if (!fstab)
1924                 bb_perror_msg_and_die("can't read %s", fstabname);
1925
1926         // Loop through entries until we find what we're looking for
1927         memset(mtpair, 0, sizeof(mtpair));
1928         for (;;) {
1929                 struct mntent *mtother = (mtcur==mtpair ? mtpair+1 : mtpair);
1930
1931                 // Get next fstab entry
1932                 if (!getmntent_r(fstab, mtcur, getmntent_buf
1933                                         + (mtcur==mtpair ? GETMNTENT_BUFSIZE/2 : 0),
1934                                 GETMNTENT_BUFSIZE/2)
1935                 ) { // End of fstab/mtab is reached
1936                         mtcur = mtother; // the thing we found last time
1937                         break;
1938                 }
1939
1940                 // If we're trying to mount something specific and this isn't it,
1941                 // skip it.  Note we must match the exact text in fstab (ala
1942                 // "proc") or a full path from root
1943                 if (argv[0]) {
1944
1945                         // Is this what we're looking for?
1946                         if (strcmp(argv[0], mtcur->mnt_fsname) != 0
1947                          && strcmp(storage_path, mtcur->mnt_fsname) != 0
1948                          && strcmp(argv[0], mtcur->mnt_dir) != 0
1949                          && strcmp(storage_path, mtcur->mnt_dir) != 0
1950                         ) {
1951                                 continue; // no
1952                         }
1953
1954                         // Remember this entry.  Something later may have
1955                         // overmounted it, and we want the _last_ match.
1956                         mtcur = mtother;
1957
1958                 // If we're mounting all
1959                 } else {
1960                         struct mntent *mp;
1961                         // No, mount -a won't mount anything,
1962                         // even user mounts, for mere humans
1963                         if (nonroot)
1964                                 bb_error_msg_and_die(bb_msg_you_must_be_root);
1965
1966                         // Does type match? (NULL matches always)
1967                         if (!match_fstype(mtcur, fstype))
1968                                 continue;
1969
1970                         // Skip noauto and swap anyway
1971                         if ((parse_mount_options(mtcur->mnt_opts, NULL) & (MOUNT_NOAUTO | MOUNT_SWAP))
1972                         // swap is bogus "fstype", parse_mount_options can't check fstypes
1973                          || strcasecmp(mtcur->mnt_type, "swap") == 0
1974                         ) {
1975                                 continue;
1976                         }
1977
1978                         // Does (at least one) option match?
1979                         // (NULL matches always)
1980                         if (!match_opt(mtcur->mnt_opts, O_optmatch))
1981                                 continue;
1982
1983                         resolve_mount_spec(&mtcur->mnt_fsname);
1984
1985                         // NFS mounts want this to be xrealloc-able
1986                         mtcur->mnt_opts = xstrdup(mtcur->mnt_opts);
1987
1988                         // If nothing is mounted on this directory...
1989                         // (otherwise repeated "mount -a" mounts everything again)
1990                         mp = find_mount_point(mtcur->mnt_dir, /*subdir_too:*/ 0);
1991                         // We do not check fsname match of found mount point -
1992                         // "/" may have fsname of "/dev/root" while fstab
1993                         // says "/dev/something_else".
1994                         if (mp) {
1995                                 if (verbose) {
1996                                         bb_error_msg("according to %s, "
1997                                                 "%s is already mounted on %s",
1998                                                 bb_path_mtab_file,
1999                                                 mp->mnt_fsname, mp->mnt_dir);
2000                                 }
2001                         } else {
2002                                 // ...mount this thing
2003                                 if (singlemount(mtcur, /*ignore_busy:*/ 1)) {
2004                                         // Count number of failed mounts
2005                                         rc++;
2006                                 }
2007                         }
2008                         free(mtcur->mnt_opts);
2009                 }
2010         }
2011
2012         // End of fstab/mtab is reached.
2013         // Were we looking for something specific?
2014         if (argv[0]) { // yes
2015                 long l;
2016
2017                 // If we didn't find anything, complain
2018                 if (!mtcur->mnt_fsname)
2019                         bb_error_msg_and_die("can't find %s in %s",
2020                                 argv[0], fstabname);
2021
2022                 // What happens when we try to "mount swap_partition"?
2023                 // (fstab containts "swap_partition swap swap defaults 0 0")
2024                 // util-linux-ng 2.13.1 does this:
2025                 // stat("/sbin/mount.swap", 0x7fff62a3a350) = -1 ENOENT (No such file or directory)
2026                 // mount("swap_partition", "swap", "swap", MS_MGC_VAL, NULL) = -1 ENOENT (No such file or directory)
2027                 // lstat("swap", 0x7fff62a3a640)           = -1 ENOENT (No such file or directory)
2028                 // write(2, "mount: mount point swap does not exist\n", 39) = 39
2029                 // exit_group(32)                          = ?
2030 #if 0
2031                 // In case we want to simply skip swap partitions:
2032                 l = parse_mount_options(mtcur->mnt_opts, NULL);
2033                 if ((l & MOUNT_SWAP)
2034                 // swap is bogus "fstype", parse_mount_options can't check fstypes
2035                  || strcasecmp(mtcur->mnt_type, "swap") == 0
2036                 ) {
2037                         goto ret;
2038                 }
2039 #endif
2040                 if (nonroot) {
2041                         // fstab must have "users" or "user"
2042                         l = parse_mount_options(mtcur->mnt_opts, NULL);
2043                         if (!(l & MOUNT_USERS))
2044                                 bb_error_msg_and_die(bb_msg_you_must_be_root);
2045                 }
2046
2047                 //util-linux-2.12 does not do this check.
2048                 //// If nothing is mounted on this directory...
2049                 //// (otherwise repeated "mount FOO" mounts FOO again)
2050                 //mp = find_mount_point(mtcur->mnt_dir, /*subdir_too:*/ 0);
2051                 //if (mp) {
2052                 //      bb_error_msg("according to %s, "
2053                 //              "%s is already mounted on %s",
2054                 //              bb_path_mtab_file,
2055                 //              mp->mnt_fsname, mp->mnt_dir);
2056                 //} else {
2057                         // ...mount the last thing we found
2058                         mtcur->mnt_opts = xstrdup(mtcur->mnt_opts);
2059                         append_mount_options(&(mtcur->mnt_opts), cmdopts);
2060                         resolve_mount_spec(&mtpair->mnt_fsname);
2061                         rc = singlemount(mtcur, /*ignore_busy:*/ 0);
2062                         if (ENABLE_FEATURE_CLEAN_UP)
2063                                 free(mtcur->mnt_opts);
2064                 //}
2065         }
2066
2067  //ret:
2068         if (ENABLE_FEATURE_CLEAN_UP)
2069                 endmntent(fstab);
2070         if (ENABLE_FEATURE_CLEAN_UP) {
2071                 free(storage_path);
2072                 free(cmdopts);
2073         }
2074
2075 //TODO: exitcode should be ORed mask of (from "man mount"):
2076 // 0 success
2077 // 1 incorrect invocation or permissions
2078 // 2 system error (out of memory, cannot fork, no more loop devices)
2079 // 4 internal mount bug or missing nfs support in mount
2080 // 8 user interrupt
2081 //16 problems writing or locking /etc/mtab
2082 //32 mount failure
2083 //64 some mount succeeded
2084         return rc;
2085 }