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