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