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