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  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  *
  21  * 3/21/1999    Charles P. Wright <cpwright@cpwright.com>
  22  *              searches through fstab when -a is passed
  23  *              will try mounting stuff with all fses when passed -t auto
  24  *
  25  * 1999-04-17   Dave Cinege...Rewrote -t auto. Fixed ro mtab.
  26  *
  27  * 1999-10-07   Erik Andersen <andersen@lineo.com>, <andersee@debian.org>.
  28  *              Rewrite of a lot of code. Removed mtab usage (I plan on
  29  *              putting it back as a compile-time option some time),
  30  *              major adjustments to option parsing, and some serious
  31  *              dieting all around.
  32  *
  33  * 1999-11-06   mtab suppport is back - andersee
  34  *
  35  * 2000-01-12   Ben Collins <bcollins@debian.org>, Borrowed utils-linux's
  36  *              mount to add loop support.
  37  */
  38
  39 #include "internal.h"
  40 #include <stdlib.h>
  41 #include <unistd.h>
  42 #include <errno.h>
  43 #include <string.h>
  44 #include <stdio.h>
  45 #include <mntent.h>
  46 #include <sys/mount.h>
  47 #include <ctype.h>
  48 #if defined BB_FEATURE_USE_DEVPS_PATCH
  49 #include <linux/devmtab.h>
  50 #endif
  51
  52 /* 2.0.x. kernels don't know about MS_NODIRATIME */
  53 #ifndef MS_NODIRATIME
  54 #define MS_NODIRATIME   2048    /* Do not update directory access times */
  55 #endif
  56
  57
  58
  59 #if defined BB_FEATURE_MOUNT_LOOP
  60 #include <fcntl.h>
  61 #include <sys/ioctl.h>
  62
  63
  64 static int use_loop = FALSE;
  65 #endif
  66
  67 extern const char mtab_file[];  /* Defined in utility.c */
  68
  69 static const char mount_usage[] =
  70         "mount [flags] device directory [-o options,more-options]\n"
  71 #ifndef BB_FEATURE_TRIVIAL_HELP
  72         "\nMount a filesystem\n\n"
  73         "Flags:\n"
  74         "\t-a:\t\tMount all filesystems in fstab.\n"
  75 #ifdef BB_MTAB
  76         "\t-f:\t\t\"Fake\" mount. Add entry to mount table but don't mount it.\n"
  77         "\t-n:\t\tDon't write a mount table entry.\n"
  78 #endif
  79         "\t-o option:\tOne of many filesystem options, listed below.\n"
  80         "\t-r:\t\tMount the filesystem read-only.\n"
  81         "\t-t fs-type:\tSpecify the filesystem type.\n"
  82         "\t-w:\t\tMount for reading and writing (default).\n"
  83         "\n"
  84         "Options for use with the \"-o\" flag:\n"
  85         "\tasync/sync:\tWrites are asynchronous / synchronous.\n"
  86         "\tatime/noatime:\tEnable / disable updates to inode access times.\n"
  87         "\tdev/nodev:\tAllow use of special device files / disallow them.\n"
  88         "\texec/noexec:\tAllow use of executable files / disallow them.\n"
  89 #if defined BB_FEATURE_MOUNT_LOOP
  90         "\tloop:\t\tMounts a file via loop device.\n"
  91 #endif
  92         "\tsuid/nosuid:\tAllow set-user-id-root programs / disallow them.\n"
  93         "\tremount:\tRe-mount a currently-mounted filesystem, changing its flags.\n"
  94         "\tro/rw:\t\tMount for read-only / read-write.\n"
  95         "\nThere are EVEN MORE flags that are specific to each filesystem.\n"
  96         "You'll have to see the written documentation for those.\n"
  97 #endif
  98         ;
  99
 100
 101 struct mount_options {
 102         const char *name;
 103         unsigned long and;
 104         unsigned long or;
 105 };
 106
 107 static const struct mount_options mount_options[] = {
 108         {"async", ~MS_SYNCHRONOUS, 0},
 109         {"atime", ~0, ~MS_NOATIME},
 110         {"defaults", ~0, 0},
 111         {"dev", ~MS_NODEV, 0},
 112         {"diratime", ~0, ~MS_NODIRATIME},
 113         {"exec", ~MS_NOEXEC, 0},
 114         {"noatime", ~0, MS_NOATIME},
 115         {"nodev", ~0, MS_NODEV},
 116         {"nodiratime", ~0, MS_NODIRATIME},
 117         {"noexec", ~0, MS_NOEXEC},
 118         {"nosuid", ~0, MS_NOSUID},
 119         {"remount", ~0, MS_REMOUNT},
 120         {"ro", ~0, MS_RDONLY},
 121         {"rw", ~MS_RDONLY, 0},
 122         {"suid", ~MS_NOSUID, 0},
 123         {"sync", ~0, MS_SYNCHRONOUS},
 124         {0, 0, 0}
 125 };
 126
 127 static int
 128 do_mount(char *specialfile, char *dir, char *filesystemtype,
 129                  long flags, void *string_flags, int useMtab, int fakeIt,
 130                  char *mtab_opts)
 131 {
 132         int status = 0;
 133         char *lofile = NULL;
 134
 135 #if defined BB_MTAB
 136         if (fakeIt == FALSE)
 137 #endif
 138         {
 139 #if defined BB_FEATURE_MOUNT_LOOP
 140                 if (use_loop==TRUE) {
 141                         int loro = flags & MS_RDONLY;
 142                         char *lofile = specialfile;
 143
 144                         specialfile = find_unused_loop_device();
 145                         if (specialfile == NULL) {
 146                                 fprintf(stderr, "Could not find a spare loop device\n");
 147                                 return (FALSE);
 148                         }
 149                         if (set_loop(specialfile, lofile, 0, &loro)) {
 150                                 fprintf(stderr, "Could not setup loop device\n");
 151                                 return (FALSE);
 152                         }
 153                         if (!(flags & MS_RDONLY) && loro) {     /* loop is ro, but wanted rw */
 154                                 fprintf(stderr, "WARNING: loop device is read-only\n");
 155                                 flags &= ~MS_RDONLY;
 156                         }
 157                 }
 158 #endif
 159                 status = mount(specialfile, dir, filesystemtype, flags, string_flags);
 160         }
 161
 162
 163         /* If the mount was sucessful, do anything needed, then return TRUE */
 164         if (status == 0) {
 165
 166 #if defined BB_MTAB
 167                 if (useMtab == TRUE) {
 168                         write_mtab(specialfile, dir, filesystemtype, flags, mtab_opts);
 169                 }
 170 #endif
 171                 return (TRUE);
 172         }
 173
 174         /* Bummer.  mount failed.  Clean up */
 175 #if defined BB_FEATURE_MOUNT_LOOP
 176         if (lofile != NULL) {
 177                 del_loop(specialfile);
 178         }
 179 #endif
 180
 181         if (errno == EPERM) {
 182                 fatalError("mount: permission denied. Are you root?\n");
 183         }
 184
 185         return (FALSE);
 186 }
 187
 188
 189
 190 /* Seperate standard mount options from the nonstandard string options */
 191 static void
 192 parse_mount_options(char *options, unsigned long *flags, char *strflags)
 193 {
 194         while (options) {
 195                 int gotone = FALSE;
 196                 char *comma = strchr(options, ',');
 197                 const struct mount_options *f = mount_options;
 198
 199                 if (comma)
 200                         *comma = '\0';
 201
 202                 while (f->name != 0) {
 203                         if (strcasecmp(f->name, options) == 0) {
 204
 205                                 *flags &= f->and;
 206                                 *flags |= f->or;
 207                                 gotone = TRUE;
 208                                 break;
 209                         }
 210                         f++;
 211                 }
 212 #if defined BB_FEATURE_MOUNT_LOOP
 213                 if (gotone == FALSE && !strcasecmp("loop", options)) {  /* loop device support */
 214                         use_loop = TRUE;
 215                         gotone = TRUE;
 216                 }
 217 #endif
 218                 if (*strflags && strflags != '\0' && gotone == FALSE) {
 219                         char *temp = strflags;
 220
 221                         temp += strlen(strflags);
 222                         *temp++ = ',';
 223                         *temp++ = '\0';
 224                 }
 225                 if (gotone == FALSE)
 226                         strcat(strflags, options);
 227                 if (comma) {
 228                         *comma = ',';
 229                         options = ++comma;
 230                 } else {
 231                         break;
 232                 }
 233         }
 234 }
 235
 236 int
 237 mount_one(char *blockDevice, char *directory, char *filesystemType,
 238                   unsigned long flags, char *string_flags, int useMtab, int fakeIt,
 239                   char *mtab_opts, int whineOnErrors)
 240 {
 241         int status = 0;
 242
 243 #if defined BB_FEATURE_USE_PROCFS
 244         char buf[255];
 245         if (strcmp(filesystemType, "auto") == 0) {
 246                 FILE *f = fopen("/proc/filesystems", "r");
 247
 248                 if (f == NULL)
 249                         return (FALSE);
 250
 251                 while (fgets(buf, sizeof(buf), f) != NULL) {
 252                         filesystemType = buf;
 253                         if (*filesystemType == '\t') {  // Not a nodev filesystem
 254
 255                                 // Add NULL termination to each line
 256                                 while (*filesystemType && *filesystemType != '\n')
 257                                         filesystemType++;
 258                                 *filesystemType = '\0';
 259
 260                                 filesystemType = buf;
 261                                 filesystemType++;       // hop past tab
 262
 263                                 status = do_mount(blockDevice, directory, filesystemType,
 264                                                                   flags | MS_MGC_VAL, string_flags,
 265                                                                   useMtab, fakeIt, mtab_opts);
 266                                 if (status == TRUE)
 267                                         break;
 268                         }
 269                 }
 270                 fclose(f);
 271         } else
 272 #endif
 273 #if defined BB_FEATURE_USE_DEVPS_PATCH
 274         if (strcmp(filesystemType, "auto") == 0) {
 275                 int fd, i, numfilesystems;
 276                 char device[] = "/dev/mtab";
 277                 struct k_fstype *fslist;
 278
 279                 /* open device */
 280                 fd = open(device, O_RDONLY);
 281                 if (fd < 0)
 282                         fatalError("open failed for `%s': %s\n", device, strerror (errno));
 283
 284                 /* How many filesystems?  We need to know to allocate enough space */
 285                 numfilesystems = ioctl (fd, DEVMTAB_COUNT_FILESYSTEMS);
 286                 if (numfilesystems<0)
 287                         fatalError("\nDEVMTAB_COUNT_FILESYSTEMS: %s\n", strerror (errno));
 288                 fslist = (struct k_fstype *) calloc ( numfilesystems, sizeof(struct k_fstype));
 289
 290                 /* Grab the list of available filesystems */
 291                 status = ioctl (fd, DEVMTAB_GET_FILESYSTEMS, fslist);
 292                 if (status<0)
 293                         fatalError("\nDEVMTAB_GET_FILESYSTEMS: %s\n", strerror (errno));
 294
 295                 /* Walk the list trying to mount filesystems
 296                  * that do not claim to be nodev filesystems */
 297                 for( i = 0 ; i < numfilesystems ; i++) {
 298                         if (fslist[i].mnt_nodev)
 299                                 continue;
 300                         status = do_mount(blockDevice, directory, fslist[i].mnt_type,
 301                                                           flags | MS_MGC_VAL, string_flags,
 302                                                           useMtab, fakeIt, mtab_opts);
 303                         if (status == TRUE)
 304                                 break;
 305                 }
 306                 free( fslist);
 307                 close(fd);
 308         } else
 309 #endif
 310         {
 311                 status = do_mount(blockDevice, directory, filesystemType,
 312                                                   flags | MS_MGC_VAL, string_flags, useMtab,
 313                                                   fakeIt, mtab_opts);
 314         }
 315
 316         if (status == FALSE) {
 317                 if (whineOnErrors == TRUE) {
 318                         fprintf(stderr, "Mounting %s on %s failed: %s\n",
 319                                         blockDevice, directory, strerror(errno));
 320                 }
 321                 return (FALSE);
 322         }
 323         return (TRUE);
 324 }
 325
 326 extern int mount_main(int argc, char **argv)
 327 {
 328         char string_flags_buf[1024] = "";
 329         char *string_flags = string_flags_buf;
 330         char *extra_opts = string_flags_buf;
 331         unsigned long flags = 0;
 332         char *filesystemType = "auto";
 333         char *device = NULL;
 334         char *directory = NULL;
 335         int all = FALSE;
 336         int fakeIt = FALSE;
 337         int useMtab = TRUE;
 338         int i;
 339
 340 #if defined BB_FEATURE_USE_DEVPS_PATCH
 341         if (argc == 1) {
 342                 int fd, i, numfilesystems;
 343                 char device[] = "/dev/mtab";
 344                 struct k_mntent *mntentlist;
 345
 346                 /* open device */
 347                 fd = open(device, O_RDONLY);
 348                 if (fd < 0)
 349                         fatalError("open failed for `%s': %s\n", device, strerror (errno));
 350
 351                 /* How many mounted filesystems?  We need to know to
 352                  * allocate enough space for later... */
 353                 numfilesystems = ioctl (fd, DEVMTAB_COUNT_MOUNTS);
 354                 if (numfilesystems<0)
 355                         fatalError( "\nDEVMTAB_COUNT_MOUNTS: %s\n", strerror (errno));
 356                 mntentlist = (struct k_mntent *) calloc ( numfilesystems, sizeof(struct k_mntent));
 357
 358                 /* Grab the list of mounted filesystems */
 359                 if (ioctl (fd, DEVMTAB_GET_MOUNTS, mntentlist)<0)
 360                         fatalError( "\nDEVMTAB_GET_MOUNTS: %s\n", strerror (errno));
 361
 362                 for( i = 0 ; i < numfilesystems ; i++) {
 363                         fprintf( stdout, "%s %s %s %s %d %d\n", mntentlist[i].mnt_fsname,
 364                                         mntentlist[i].mnt_dir, mntentlist[i].mnt_type,
 365                                         mntentlist[i].mnt_opts, mntentlist[i].mnt_freq,
 366                                         mntentlist[i].mnt_passno);
 367                 }
 368                 /* Don't bother to close files or free memory.  Exit
 369                  * does that automagically, so we can save a few bytes */
 370 #if 0
 371                 free( mntentlist);
 372                 close(fd);
 373 #endif
 374                 exit(TRUE);
 375         }
 376 #else
 377         if (argc == 1) {
 378                 FILE *mountTable = setmntent(mtab_file, "r");
 379
 380                 if (mountTable) {
 381                         struct mntent *m;
 382
 383                         while ((m = getmntent(mountTable)) != 0) {
 384                                 char *blockDevice = m->mnt_fsname;
 385                                 if (strcmp(blockDevice, "/dev/root") == 0) {
 386                                         find_real_root_device_name( blockDevice);
 387                                 }
 388                                 printf("%s on %s type %s (%s)\n", blockDevice, m->mnt_dir,
 389                                            m->mnt_type, m->mnt_opts);
 390                         }
 391                         endmntent(mountTable);
 392                 } else {
 393                         perror(mtab_file);
 394                 }
 395                 exit(TRUE);
 396         }
 397 #endif
 398
 399         /* Parse options */
 400         i = --argc;
 401         argv++;
 402         while (i > 0 && **argv) {
 403                 if (**argv == '-') {
 404                         char *opt = *argv;
 405
 406                         while (i > 0 && *++opt)
 407                                 switch (*opt) {
 408                                 case 'o':
 409                                         if (--i == 0) {
 410                                                 goto goodbye;
 411                                         }
 412                                         parse_mount_options(*(++argv), &flags, string_flags);
 413                                         break;
 414                                 case 'r':
 415                                         flags |= MS_RDONLY;
 416                                         break;
 417                                 case 't':
 418                                         if (--i == 0) {
 419                                                 goto goodbye;
 420                                         }
 421                                         filesystemType = *(++argv);
 422                                         break;
 423                                 case 'w':
 424                                         flags &= ~MS_RDONLY;
 425                                         break;
 426                                 case 'a':
 427                                         all = TRUE;
 428                                         break;
 429                                 case 'f':
 430                                         fakeIt = TRUE;
 431                                         break;
 432 #ifdef BB_MTAB
 433                                 case 'n':
 434                                         useMtab = FALSE;
 435                                         break;
 436 #endif
 437                                 case 'v':
 438                                         break; /* ignore -v */
 439                                 case 'h':
 440                                 case '-':
 441                                         goto goodbye;
 442                                 }
 443                 } else {
 444                         if (device == NULL)
 445                                 device = *argv;
 446                         else if (directory == NULL)
 447                                 directory = *argv;
 448                         else {
 449                                 goto goodbye;
 450                         }
 451                 }
 452                 i--;
 453                 argv++;
 454         }
 455
 456         if (all == TRUE) {
 457                 struct mntent *m;
 458                 FILE *f = setmntent("/etc/fstab", "r");
 459
 460                 if (f == NULL)
 461                         fatalError( "\nCannot read /etc/fstab: %s\n", strerror (errno));
 462
 463                 while ((m = getmntent(f)) != NULL) {
 464                         // If the filesystem isn't noauto,
 465                         // and isn't swap or nfs, then mount it
 466                         if ((!strstr(m->mnt_opts, "noauto")) &&
 467                                         (!strstr(m->mnt_type, "swap")) &&
 468                                         (!strstr(m->mnt_type, "nfs"))) {
 469                                 flags = 0;
 470                                 *string_flags = '\0';
 471                                 parse_mount_options(m->mnt_opts, &flags, string_flags);
 472                                 if (mount_one(m->mnt_fsname, m->mnt_dir, m->mnt_type,
 473                                                         flags, string_flags, useMtab, fakeIt,
 474                                                         extra_opts, FALSE)==FALSE)
 475                                 {
 476                                         /* Try again, but this time try a remount */
 477                                         mount_one(m->mnt_fsname, m->mnt_dir, m->mnt_type,
 478                                                         flags|MS_REMOUNT, string_flags, useMtab, fakeIt,
 479                                                         extra_opts, TRUE);
 480                                 }
 481                         }
 482                 }
 483                 endmntent(f);
 484         } else {
 485                 if (device && directory) {
 486 #ifdef BB_NFSMOUNT
 487                         if (strchr(device, ':') != NULL)
 488                                 filesystemType = "nfs";
 489                         if (strcmp(filesystemType, "nfs") == 0) {
 490                                 int ret;
 491                                 ret = nfsmount (device, directory, &flags,
 492                                                 &extra_opts, &string_flags, 1);
 493                                 if (ret != 0)
 494                                         fatalError("nfsmount failed: %s\n", strerror(errno));
 495                         }
 496 #endif
 497                         exit(mount_one(device, directory, filesystemType,
 498                                                    flags, string_flags, useMtab, fakeIt,
 499                                                    extra_opts, TRUE));
 500                 } else {
 501                         goto goodbye;
 502                 }
 503         }
 504         exit(TRUE);
 505
 506   goodbye:
 507         usage(mount_usage);
 508 }