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