a few minor cleanups.
[oweals/busybox.git] / 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 #if defined BB_FEATURE_USE_DEVPS_PATCH
49 #include <linux/devmtab.h>
50 #endif
51 #ifndef MS_RDONLY
52 #include <linux/fs.h>
53 #endif
54
55
56 #if defined BB_FEATURE_MOUNT_LOOP
57 #include <fcntl.h>
58 #include <sys/ioctl.h>
59 #include <linux/loop.h>
60
61
62 static int use_loop = FALSE;
63 #endif
64
65 extern const char mtab_file[];  /* Defined in utility.c */
66
67 static const char mount_usage[] = 
68         "mount [flags] device directory [-o options,more-options]\n"
69 #ifndef BB_FEATURE_TRIVIAL_HELP
70         "\nMount a filesystem\n\n"
71         "Flags:\n" 
72         "\t-a:\t\tMount all filesystems in fstab.\n"
73 #ifdef BB_MTAB
74         "\t-f:\t\t\"Fake\" mount. Add entry to mount table but don't mount it.\n"
75         "\t-n:\t\tDon't write a mount table entry.\n"
76 #endif
77         "\t-o option:\tOne of many filesystem options, listed below.\n"
78         "\t-r:\t\tMount the filesystem read-only.\n"
79         "\t-t fs-type:\tSpecify the filesystem type.\n"
80         "\t-w:\t\tMount for reading and writing (default).\n"
81         "\n"
82         "Options for use with the \"-o\" flag:\n"
83         "\tasync/sync:\tWrites are asynchronous / synchronous.\n"
84         "\tatime/noatime:\tEnable / disable updates to inode access times.\n"
85         "\tdev/nodev:\tAllow use of special device files / disallow them.\n"
86         "\texec/noexec:\tAllow use of executable files / disallow them.\n"
87 #if defined BB_FEATURE_MOUNT_LOOP
88         "\tloop:\t\tMounts a file via loop device.\n"
89 #endif
90         "\tsuid/nosuid:\tAllow set-user-id-root programs / disallow them.\n"
91         "\tremount:\tRe-mount a currently-mounted filesystem, changing its flags.\n"
92         "\tro/rw:\t\tMount for read-only / read-write.\n"
93         "\nThere are EVEN MORE flags that are specific to each filesystem.\n"
94         "You'll have to see the written documentation for those.\n"
95 #endif
96         ;
97
98
99 struct mount_options {
100         const char *name;
101         unsigned long and;
102         unsigned long or;
103 };
104
105 static const struct mount_options mount_options[] = {
106         {"async", ~MS_SYNCHRONOUS, 0},
107         {"atime", ~0, ~MS_NOATIME},
108         {"defaults", ~0, 0},
109         {"dev", ~MS_NODEV, 0},
110         {"diratime", ~0, ~MS_NODIRATIME},
111         {"exec", ~MS_NOEXEC, 0},
112         {"noatime", ~0, MS_NOATIME},
113         {"nodev", ~0, MS_NODEV},
114         {"nodiratime", ~0, MS_NODIRATIME},
115         {"noexec", ~0, MS_NOEXEC},
116         {"nosuid", ~0, MS_NOSUID},
117         {"remount", ~0, MS_REMOUNT},
118         {"ro", ~0, MS_RDONLY},
119         {"rw", ~MS_RDONLY, 0},
120         {"suid", ~MS_NOSUID, 0},
121         {"sync", ~0, MS_SYNCHRONOUS},
122         {0, 0, 0}
123 };
124
125 static int
126 do_mount(char *specialfile, char *dir, char *filesystemtype,
127                  long flags, void *string_flags, int useMtab, int fakeIt,
128                  char *mtab_opts)
129 {
130         int status = 0;
131         char *lofile = NULL;
132
133 #if defined BB_MTAB
134         if (fakeIt == FALSE)
135 #endif
136         {
137 #if defined BB_FEATURE_MOUNT_LOOP
138                 if (use_loop==TRUE) {
139                         int loro = flags & MS_RDONLY;
140                         char *lofile = specialfile;
141
142                         specialfile = find_unused_loop_device();
143                         if (specialfile == NULL) {
144                                 fprintf(stderr, "Could not find a spare loop device\n");
145                                 return (FALSE);
146                         }
147                         if (set_loop(specialfile, lofile, 0, &loro)) {
148                                 fprintf(stderr, "Could not setup loop device\n");
149                                 return (FALSE);
150                         }
151                         if (!(flags & MS_RDONLY) && loro) {     /* loop is ro, but wanted rw */
152                                 fprintf(stderr, "WARNING: loop device is read-only\n");
153                                 flags &= ~MS_RDONLY;
154                         }
155                 }
156 #endif
157                 status = mount(specialfile, dir, filesystemtype, flags, string_flags);
158         }
159
160
161         /* If the mount was sucessful, do anything needed, then return TRUE */
162         if (status == 0) {
163
164 #if defined BB_MTAB
165                 if (useMtab == TRUE) {
166                         write_mtab(specialfile, dir, filesystemtype, flags, mtab_opts);
167                 }
168 #endif
169                 return (TRUE);
170         }
171
172         /* Bummer.  mount failed.  Clean up */
173 #if defined BB_FEATURE_MOUNT_LOOP
174         if (lofile != NULL) {
175                 del_loop(specialfile);
176         }
177 #endif
178
179         if (errno == EPERM) {
180                 fatalError("mount: permission denied. Are you root?\n");
181         }
182
183         return (FALSE);
184 }
185
186
187
188 /* Seperate standard mount options from the nonstandard string options */
189 static void
190 parse_mount_options(char *options, unsigned long *flags, char *strflags)
191 {
192         while (options) {
193                 int gotone = FALSE;
194                 char *comma = strchr(options, ',');
195                 const struct mount_options *f = mount_options;
196
197                 if (comma)
198                         *comma = '\0';
199
200                 while (f->name != 0) {
201                         if (strcasecmp(f->name, options) == 0) {
202
203                                 *flags &= f->and;
204                                 *flags |= f->or;
205                                 gotone = TRUE;
206                                 break;
207                         }
208                         f++;
209                 }
210 #if defined BB_FEATURE_MOUNT_LOOP
211                 if (gotone == FALSE && !strcasecmp("loop", options)) {  /* loop device support */
212                         use_loop = TRUE;
213                         gotone = TRUE;
214                 }
215 #endif
216                 if (*strflags && strflags != '\0' && gotone == FALSE) {
217                         char *temp = strflags;
218
219                         temp += strlen(strflags);
220                         *temp++ = ',';
221                         *temp++ = '\0';
222                 }
223                 if (gotone == FALSE)
224                         strcat(strflags, options);
225                 if (comma) {
226                         *comma = ',';
227                         options = ++comma;
228                 } else {
229                         break;
230                 }
231         }
232 }
233
234 int
235 mount_one(char *blockDevice, char *directory, char *filesystemType,
236                   unsigned long flags, char *string_flags, int useMtab, int fakeIt,
237                   char *mtab_opts, int whineOnErrors)
238 {
239         int status = 0;
240
241 #if defined BB_FEATURE_USE_PROCFS
242         char buf[255];
243         if (strcmp(filesystemType, "auto") == 0) {
244                 FILE *f = fopen("/proc/filesystems", "r");
245
246                 if (f == NULL)
247                         return (FALSE);
248
249                 while (fgets(buf, sizeof(buf), f) != NULL) {
250                         filesystemType = buf;
251                         if (*filesystemType == '\t') {  // Not a nodev filesystem
252
253                                 // Add NULL termination to each line
254                                 while (*filesystemType && *filesystemType != '\n')
255                                         filesystemType++;
256                                 *filesystemType = '\0';
257
258                                 filesystemType = buf;
259                                 filesystemType++;       // hop past tab
260
261                                 status = do_mount(blockDevice, directory, filesystemType,
262                                                                   flags | MS_MGC_VAL, string_flags,
263                                                                   useMtab, fakeIt, mtab_opts);
264                                 if (status == TRUE)
265                                         break;
266                         }
267                 }
268                 fclose(f);
269         } else
270 #endif
271 #if defined BB_FEATURE_USE_DEVPS_PATCH
272         if (strcmp(filesystemType, "auto") == 0) {
273                 int fd, i, numfilesystems;
274                 char device[] = "/dev/mtab";
275                 struct k_fstype *fslist;
276
277                 /* open device */ 
278                 fd = open(device, O_RDONLY);
279                 if (fd < 0)
280                         fatalError("open failed for `%s': %s\n", device, strerror (errno));
281
282                 /* How many filesystems?  We need to know to allocate enough space */
283                 numfilesystems = ioctl (fd, DEVMTAB_COUNT_FILESYSTEMS);
284                 if (numfilesystems<0)
285                         fatalError("\nDEVMTAB_COUNT_FILESYSTEMS: %s\n", strerror (errno));
286                 fslist = (struct k_fstype *) calloc ( numfilesystems, sizeof(struct k_fstype));
287
288                 /* Grab the list of available filesystems */
289                 status = ioctl (fd, DEVMTAB_GET_FILESYSTEMS, fslist);
290                 if (status<0)
291                         fatalError("\nDEVMTAB_GET_FILESYSTEMS: %s\n", strerror (errno));
292
293                 /* Walk the list trying to mount filesystems 
294                  * that do not claim to be nodev filesystems */
295                 for( i = 0 ; i < numfilesystems ; i++) {
296                         if (fslist[i].mnt_nodev)
297                                 continue;
298                         status = do_mount(blockDevice, directory, fslist[i].mnt_type,
299                                                           flags | MS_MGC_VAL, string_flags,
300                                                           useMtab, fakeIt, mtab_opts);
301                         if (status == TRUE)
302                                 break;
303                 }
304                 free( fslist);
305                 close(fd);
306         } else
307 #endif
308         {
309                 status = do_mount(blockDevice, directory, filesystemType,
310                                                   flags | MS_MGC_VAL, string_flags, useMtab,
311                                                   fakeIt, mtab_opts);
312         }
313
314         if (status == FALSE) {
315                 if (whineOnErrors == TRUE) {
316                         fprintf(stderr, "Mounting %s on %s failed: %s\n",
317                                         blockDevice, directory, strerror(errno));
318                 }
319                 return (FALSE);
320         }
321         return (TRUE);
322 }
323
324 extern int mount_main(int argc, char **argv)
325 {
326         char string_flags_buf[1024] = "";
327         char *string_flags = string_flags_buf;
328         char *extra_opts = string_flags_buf;
329         unsigned long flags = 0;
330         char *filesystemType = "auto";
331         char *device = NULL;
332         char *directory = NULL;
333         int all = FALSE;
334         int fakeIt = FALSE;
335         int useMtab = TRUE;
336         int i;
337
338 #if defined BB_FEATURE_USE_DEVPS_PATCH
339         if (argc == 1) {
340                 int fd, i, numfilesystems;
341                 char device[] = "/dev/mtab";
342                 struct k_mntent *mntentlist;
343
344                 /* open device */ 
345                 fd = open(device, O_RDONLY);
346                 if (fd < 0)
347                         fatalError("open failed for `%s': %s\n", device, strerror (errno));
348
349                 /* How many mounted filesystems?  We need to know to 
350                  * allocate enough space for later... */
351                 numfilesystems = ioctl (fd, DEVMTAB_COUNT_MOUNTS);
352                 if (numfilesystems<0)
353                         fatalError( "\nDEVMTAB_COUNT_MOUNTS: %s\n", strerror (errno));
354                 mntentlist = (struct k_mntent *) calloc ( numfilesystems, sizeof(struct k_mntent));
355                 
356                 /* Grab the list of mounted filesystems */
357                 if (ioctl (fd, DEVMTAB_GET_MOUNTS, mntentlist)<0)
358                         fatalError( "\nDEVMTAB_GET_MOUNTS: %s\n", strerror (errno));
359
360                 for( i = 0 ; i < numfilesystems ; i++) {
361                         fprintf( stdout, "%s %s %s %s %d %d\n", mntentlist[i].mnt_fsname,
362                                         mntentlist[i].mnt_dir, mntentlist[i].mnt_type, 
363                                         mntentlist[i].mnt_opts, mntentlist[i].mnt_freq, 
364                                         mntentlist[i].mnt_passno);
365                 }
366                 /* Don't bother to close files or free memory.  Exit 
367                  * does that automagically, so we can save a few bytes */
368 #if 0
369                 free( mntentlist);
370                 close(fd);
371 #endif
372                 exit(TRUE);
373         }
374 #else
375         if (argc == 1) {
376                 FILE *mountTable = setmntent(mtab_file, "r");
377
378                 if (mountTable) {
379                         struct mntent *m;
380
381                         while ((m = getmntent(mountTable)) != 0) {
382                                 char *blockDevice = m->mnt_fsname;
383                                 if (strcmp(blockDevice, "/dev/root") == 0) {
384                                         find_real_root_device_name( blockDevice);
385                                 }
386                                 printf("%s on %s type %s (%s)\n", blockDevice, m->mnt_dir,
387                                            m->mnt_type, m->mnt_opts);
388                         }
389                         endmntent(mountTable);
390                 } else {
391                         perror(mtab_file);
392                 }
393                 exit(TRUE);
394         }
395 #endif
396
397         /* Parse options */
398         i = --argc;
399         argv++;
400         while (i > 0 && **argv) {
401                 if (**argv == '-') {
402                         char *opt = *argv;
403
404                         while (i > 0 && *++opt)
405                                 switch (*opt) {
406                                 case 'o':
407                                         if (--i == 0) {
408                                                 goto goodbye;
409                                         }
410                                         parse_mount_options(*(++argv), &flags, string_flags);
411                                         break;
412                                 case 'r':
413                                         flags |= MS_RDONLY;
414                                         break;
415                                 case 't':
416                                         if (--i == 0) {
417                                                 goto goodbye;
418                                         }
419                                         filesystemType = *(++argv);
420                                         break;
421                                 case 'w':
422                                         flags &= ~MS_RDONLY;
423                                         break;
424                                 case 'a':
425                                         all = TRUE;
426                                         break;
427                                 case 'f':
428                                         fakeIt = TRUE;
429                                         break;
430 #ifdef BB_MTAB
431                                 case 'n':
432                                         useMtab = FALSE;
433                                         break;
434 #endif
435                                 case 'v':
436                                         break; /* ignore -v */
437                                 case 'h':
438                                 case '-':
439                                         goto goodbye;
440                                 }
441                 } else {
442                         if (device == NULL)
443                                 device = *argv;
444                         else if (directory == NULL)
445                                 directory = *argv;
446                         else {
447                                 goto goodbye;
448                         }
449                 }
450                 i--;
451                 argv++;
452         }
453
454         if (all == TRUE) {
455                 struct mntent *m;
456                 FILE *f = setmntent("/etc/fstab", "r");
457
458                 if (f == NULL)
459                         fatalError( "\nCannot read /etc/fstab: %s\n", strerror (errno));
460
461                 while ((m = getmntent(f)) != NULL) {
462                         // If the filesystem isn't noauto, 
463                         // and isn't swap or nfs, then mount it
464                         if ((!strstr(m->mnt_opts, "noauto")) &&
465                                         (!strstr(m->mnt_type, "swap")) &&
466                                         (!strstr(m->mnt_type, "nfs"))) {
467                                 flags = 0;
468                                 *string_flags = '\0';
469                                 parse_mount_options(m->mnt_opts, &flags, string_flags);
470                                 if (mount_one(m->mnt_fsname, m->mnt_dir, m->mnt_type,
471                                                         flags, string_flags, useMtab, fakeIt,
472                                                         extra_opts, FALSE)==FALSE) 
473                                 {
474                                         /* Try again, but this time try a remount */
475                                         mount_one(m->mnt_fsname, m->mnt_dir, m->mnt_type,
476                                                         flags|MS_REMOUNT, string_flags, useMtab, fakeIt,
477                                                         extra_opts, TRUE);
478                                 }
479                         }
480                 }
481                 endmntent(f);
482         } else {
483                 if (device && directory) {
484 #ifdef BB_NFSMOUNT
485                         if (strchr(device, ':') != NULL)
486                                 filesystemType = "nfs";
487                         if (strcmp(filesystemType, "nfs") == 0) {
488                                 int ret;
489                                 ret = nfsmount (device, directory, &flags,
490                                                 &extra_opts, &string_flags, 1);
491                                 if (ret != 0)
492                                         fatalError("nfsmount failed: %s\n", strerror(errno));
493                         }
494 #endif
495                         exit(mount_one(device, directory, filesystemType,
496                                                    flags, string_flags, useMtab, fakeIt,
497                                                    extra_opts, TRUE));
498                 } else {
499                         goto goodbye;
500                 }
501         }
502         exit(TRUE);
503
504   goodbye:
505         usage(mount_usage);
506 }