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