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                         use_loop = FALSE;
 146                 }
 147 #endif
 148                 status =
 149                         mount(specialfile, dir, filesystemtype, flags, string_flags);
 150         }
 151
 152
 153         /* If the mount was sucessful, do anything needed, then return TRUE */
 154         if (status == 0) {
 155
 156 #if defined BB_MTAB
 157                 if (useMtab == TRUE) {
 158                         write_mtab(specialfile, dir, filesystemtype, flags, mtab_opts);
 159                 }
 160 #endif
 161                 return (TRUE);
 162         }
 163
 164         /* Bummer.  mount failed.  Clean up */
 165 #if defined BB_FEATURE_MOUNT_LOOP
 166         if (lofile != NULL) {
 167                 del_loop(specialfile);
 168         }
 169 #endif
 170         return (FALSE);
 171 }
 172
 173
 174
 175 /* Seperate standard mount options from the nonstandard string options */
 176 static void
 177 parse_mount_options(char *options, unsigned long *flags, char *strflags)
 178 {
 179         while (options) {
 180                 int gotone = FALSE;
 181                 char *comma = strchr(options, ',');
 182                 const struct mount_options *f = mount_options;
 183
 184                 if (comma)
 185                         *comma = '\0';
 186
 187                 while (f->name != 0) {
 188                         if (strcasecmp(f->name, options) == 0) {
 189
 190                                 *flags &= f->and;
 191                                 *flags |= f->or;
 192                                 gotone = TRUE;
 193                                 break;
 194                         }
 195                         f++;
 196                 }
 197 #if defined BB_FEATURE_MOUNT_LOOP
 198                 if (gotone == FALSE && !strcasecmp("loop", options)) {  /* loop device support */
 199                         use_loop = TRUE;
 200                         gotone = TRUE;
 201                 }
 202 #endif
 203                 if (*strflags && strflags != '\0' && gotone == FALSE) {
 204                         char *temp = strflags;
 205
 206                         temp += strlen(strflags);
 207                         *temp++ = ',';
 208                         *temp++ = '\0';
 209                 }
 210                 if (gotone == FALSE)
 211                         strcat(strflags, options);
 212                 if (comma) {
 213                         *comma = ',';
 214                         options = ++comma;
 215                 } else {
 216                         break;
 217                 }
 218         }
 219 }
 220
 221 int
 222 mount_one(char *blockDevice, char *directory, char *filesystemType,
 223                   unsigned long flags, char *string_flags, int useMtab, int fakeIt,
 224                   char *mtab_opts, int whineOnErrors)
 225 {
 226         int status = 0;
 227
 228 #if defined BB_FEATURE_USE_PROCFS
 229         char buf[255];
 230         if (strcmp(filesystemType, "auto") == 0) {
 231                 FILE *f = fopen("/proc/filesystems", "r");
 232
 233                 if (f == NULL)
 234                         return (FALSE);
 235
 236                 while (fgets(buf, sizeof(buf), f) != NULL) {
 237                         filesystemType = buf;
 238                         if (*filesystemType == '\t') {  // Not a nodev filesystem
 239
 240                                 // Add NULL termination to each line
 241                                 while (*filesystemType && *filesystemType != '\n')
 242                                         filesystemType++;
 243                                 *filesystemType = '\0';
 244
 245                                 filesystemType = buf;
 246                                 filesystemType++;       // hop past tab
 247
 248                                 status = do_mount(blockDevice, directory, filesystemType,
 249                                                                   flags | MS_MGC_VAL, string_flags,
 250                                                                   useMtab, fakeIt, mtab_opts);
 251                                 if (status == TRUE)
 252                                         break;
 253                         }
 254                 }
 255                 fclose(f);
 256         } else
 257 #endif
 258 #if defined BB_FEATURE_USE_DEVPS_PATCH
 259         if (strcmp(filesystemType, "auto") == 0) {
 260                 int fd, i, numfilesystems;
 261                 char device[] = "/dev/mtab";
 262                 struct k_fstype *fslist;
 263
 264                 /* open device */
 265                 fd = open(device, O_RDONLY);
 266                 if (fd < 0)
 267                         fatalError("open failed for `%s': %s\n", device, strerror (errno));
 268
 269                 /* How many filesystems?  We need to know to allocate enough space */
 270                 numfilesystems = ioctl (fd, DEVMTAB_COUNT_FILESYSTEMS);
 271                 if (numfilesystems<0)
 272                         fatalError("\nDEVMTAB_COUNT_FILESYSTEMS: %s\n", strerror (errno));
 273                 fslist = (struct k_fstype *) calloc ( numfilesystems, sizeof(struct k_fstype));
 274
 275                 /* Grab the list of available filesystems */
 276                 status = ioctl (fd, DEVMTAB_GET_FILESYSTEMS, fslist);
 277                 if (status<0)
 278                         fatalError("\nDEVMTAB_GET_FILESYSTEMS: %s\n", strerror (errno));
 279
 280                 /* Walk the list trying to mount filesystems
 281                  * that do not claim to be nodev filesystems */
 282                 for( i = 0 ; i < numfilesystems ; i++) {
 283                         if (fslist[i].mnt_nodev)
 284                                 continue;
 285                         status = do_mount(blockDevice, directory, fslist[i].mnt_type,
 286                                                           flags | MS_MGC_VAL, string_flags,
 287                                                           useMtab, fakeIt, mtab_opts);
 288                         if (status == TRUE)
 289                                 break;
 290                 }
 291                 free( fslist);
 292                 close(fd);
 293         } else
 294 #endif
 295         {
 296                 status = do_mount(blockDevice, directory, filesystemType,
 297                                                   flags | MS_MGC_VAL, string_flags, useMtab,
 298                                                   fakeIt, mtab_opts);
 299         }
 300
 301         if (status == FALSE && whineOnErrors == TRUE) {
 302                 if (whineOnErrors == TRUE) {
 303                         fprintf(stderr, "Mounting %s on %s failed: %s\n",
 304                                         blockDevice, directory, strerror(errno));
 305                 }
 306                 return (FALSE);
 307         }
 308         return (TRUE);
 309 }
 310
 311 extern int mount_main(int argc, char **argv)
 312 {
 313         char string_flags_buf[1024] = "";
 314         char *string_flags = string_flags_buf;
 315         char *extra_opts = string_flags_buf;
 316         unsigned long flags = 0;
 317         char *filesystemType = "auto";
 318         char *device = NULL;
 319         char *directory = NULL;
 320         int all = FALSE;
 321         int fakeIt = FALSE;
 322         int useMtab = TRUE;
 323         int i;
 324
 325         /* Only compiled in if BB_MTAB is not defined */
 326         whine_if_fstab_is_missing();
 327
 328 #if defined BB_FEATURE_USE_DEVPS_PATCH
 329         if (argc == 1) {
 330                 int fd, i, numfilesystems;
 331                 char device[] = "/dev/mtab";
 332                 struct k_mntent *mntentlist;
 333
 334                 /* open device */
 335                 fd = open(device, O_RDONLY);
 336                 if (fd < 0)
 337                         fatalError("open failed for `%s': %s\n", device, strerror (errno));
 338
 339                 /* How many mounted filesystems?  We need to know to
 340                  * allocate enough space for later... */
 341                 numfilesystems = ioctl (fd, DEVMTAB_COUNT_MOUNTS);
 342                 if (numfilesystems<0)
 343                         fatalError( "\nDEVMTAB_COUNT_MOUNTS: %s\n", strerror (errno));
 344                 mntentlist = (struct k_mntent *) calloc ( numfilesystems, sizeof(struct k_mntent));
 345
 346                 /* Grab the list of mounted filesystems */
 347                 if (ioctl (fd, DEVMTAB_GET_MOUNTS, mntentlist)<0)
 348                         fatalError( "\nDEVMTAB_GET_MOUNTS: %s\n", strerror (errno));
 349
 350                 for( i = 0 ; i < numfilesystems ; i++) {
 351                         fprintf( stdout, "%s %s %s %s %d %d\n", mntentlist[i].mnt_fsname,
 352                                         mntentlist[i].mnt_dir, mntentlist[i].mnt_type,
 353                                         mntentlist[i].mnt_opts, mntentlist[i].mnt_freq,
 354                                         mntentlist[i].mnt_passno);
 355                 }
 356                 free( mntentlist);
 357                 close(fd);
 358                 exit(TRUE);
 359         }
 360 #else
 361         if (argc == 1) {
 362                 FILE *mountTable = setmntent(mtab_file, "r");
 363
 364                 if (mountTable) {
 365                         struct mntent *m;
 366
 367                         while ((m = getmntent(mountTable)) != 0) {
 368                                 struct fstab *fstabItem;
 369                                 char *blockDevice = m->mnt_fsname;
 370
 371                                 /* Note that if /etc/fstab is missing, libc can't fix up /dev/root for us */
 372                                 if (strcmp(blockDevice, "/dev/root") == 0) {
 373                                         fstabItem = getfsfile("/");
 374                                         if (fstabItem != NULL)
 375                                                 blockDevice = fstabItem->fs_spec;
 376                                 }
 377                                 printf("%s on %s type %s (%s)\n", blockDevice, m->mnt_dir,
 378                                            m->mnt_type, m->mnt_opts);
 379                         }
 380                         endmntent(mountTable);
 381                 } else {
 382                         perror(mtab_file);
 383                 }
 384                 exit(TRUE);
 385         }
 386 #endif
 387
 388         /* Parse options */
 389         i = --argc;
 390         argv++;
 391         while (i > 0 && **argv) {
 392                 if (**argv == '-') {
 393                         char *opt = *argv;
 394
 395                         while (i > 0 && *++opt)
 396                                 switch (*opt) {
 397                                 case 'o':
 398                                         if (--i == 0) {
 399                                                 goto goodbye;
 400                                         }
 401                                         parse_mount_options(*(++argv), &flags, string_flags);
 402                                         break;
 403                                 case 'r':
 404                                         flags |= MS_RDONLY;
 405                                         break;
 406                                 case 't':
 407                                         if (--i == 0) {
 408                                                 goto goodbye;
 409                                         }
 410                                         filesystemType = *(++argv);
 411                                         break;
 412                                 case 'w':
 413                                         flags &= ~MS_RDONLY;
 414                                         break;
 415                                 case 'a':
 416                                         all = TRUE;
 417                                         break;
 418 #ifdef BB_MTAB
 419                                 case 'f':
 420                                         fakeIt = TRUE;
 421                                         break;
 422                                 case 'n':
 423                                         useMtab = FALSE;
 424                                         break;
 425 #endif
 426                                 case 'v':
 427                                 case 'h':
 428                                 case '-':
 429                                         goto goodbye;
 430                                 }
 431                 } else {
 432                         if (device == NULL)
 433                                 device = *argv;
 434                         else if (directory == NULL)
 435                                 directory = *argv;
 436                         else {
 437                                 goto goodbye;
 438                         }
 439                 }
 440                 i--;
 441                 argv++;
 442         }
 443
 444         if (all == TRUE) {
 445                 struct mntent *m;
 446                 FILE *f = setmntent("/etc/fstab", "r");
 447
 448                 if (f == NULL)
 449                         fatalError( "\nCannot ream /etc/fstab: %s\n", strerror (errno));
 450
 451                 while ((m = getmntent(f)) != NULL) {
 452                         // If the file system isn't noauto,
 453                         // and isn't swap or nfs, then mount it
 454                         if ((!strstr(m->mnt_opts, "noauto")) &&
 455                                 (!strstr(m->mnt_type, "swap")) &&
 456                                 (!strstr(m->mnt_type, "nfs"))) {
 457                                 flags = 0;
 458                                 *string_flags = '\0';
 459                                 parse_mount_options(m->mnt_opts, &flags, string_flags);
 460                                 /* If the directory is /, try to remount
 461                                  * with the options specified in fstab */
 462                                 if (m->mnt_dir[0] == '/' && m->mnt_dir[1] == '\0') {
 463                                         flags |= MS_REMOUNT;
 464                                 }
 465                                 if (mount_one(m->mnt_fsname, m->mnt_dir, m->mnt_type,
 466                                                   flags, string_flags, useMtab, fakeIt,
 467                                                   extra_opts, FALSE))
 468                                 {
 469                                         /* Try again, but this time try a remount */
 470                                         mount_one(m->mnt_fsname, m->mnt_dir, m->mnt_type,
 471                                                           flags|MS_REMOUNT, string_flags, useMtab, fakeIt,
 472                                                           extra_opts, TRUE);
 473                                 }
 474                         }
 475                 }
 476                 endmntent(f);
 477         } else {
 478                 if (device && directory) {
 479 #ifdef BB_NFSMOUNT
 480                         if (strcmp(filesystemType, "nfs") == 0) {
 481                                 if (nfsmount
 482                                         (device, directory, &flags, &extra_opts, &string_flags,
 483                                          1) != 0)
 484                                         exit(FALSE);
 485                         }
 486 #endif
 487                         exit(mount_one(device, directory, filesystemType,
 488                                                    flags, string_flags, useMtab, fakeIt,
 489                                                    extra_opts, TRUE));
 490                 } else {
 491                         goto goodbye;
 492                 }
 493         }
 494         exit(TRUE);
 495
 496   goodbye:
 497         usage(mount_usage);
 498 }