aboutsummaryrefslogtreecommitdiff
path: root/util-linux/mount.c
blob: cc6b73eb054271f37f2f7666434eee78343161b9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
/* vi: set sw=4 ts=4: */
/*
 * Mini mount implementation for busybox
 *
 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 * Copyright (C) 2005 by Rob Landley <rob@landley.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

#include <limits.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <mntent.h>
#include <ctype.h>
#include <sys/mount.h>
#include <fcntl.h>		// for CONFIG_FEATURE_MOUNT_LOOP
#include <sys/ioctl.h>  // for CONFIG_FEATURE_MOUNT_LOOP
#include "busybox.h"

/* This is just a warning of a common mistake.  Possibly this should be a
 * uclibc faq entry rather than in busybox... */
#if ENABLE_FEATURE_MOUNT_NFS && defined(__UCLIBC__) && ! defined(__UCLIBC_HAS_RPC__)
#error "You need to build uClibc with UCLIBC_HAS_RPC for busybox mount with NFS support to compile."
#endif

// These two aren't always defined in old headers
#ifndef MS_BIND
#define MS_BIND		4096
#endif
#ifndef MS_MOVE
#define MS_MOVE		8192
#endif

/* Consume standard mount options (from -o options or --options).
 * Set appropriate flags and collect unrecognized ones as a comma separated
 * string to pass to kernel */ 

struct {
	const char *name;
	long flags;
} static const  mount_options[] = {
	{"loop", 0},
	{"defaults", 0},
	{"noauto", 0},
	{"ro", MS_RDONLY},
	{"rw", ~MS_RDONLY},
	{"nosuid", MS_NOSUID},
	{"suid", ~MS_NOSUID},
	{"dev", ~MS_NODEV},
	{"nodev", MS_NODEV},
	{"exec", ~MS_NOEXEC},
	{"noexec", MS_NOEXEC},
	{"sync", MS_SYNCHRONOUS},
	{"async", ~MS_SYNCHRONOUS},
	{"remount", MS_REMOUNT},
	{"atime", MS_NOATIME},
	{"noatime", MS_NOATIME},
	{"diratime", MS_NODIRATIME},
	{"nodiratime", MS_NODIRATIME},
	{"bind", MS_BIND},
	{"move", MS_MOVE}
};

/* Uses the mount_options list above */
static void parse_mount_options(char *options, int *flags, char **strflags)
{
	// Loop through options
	for(;;) {
		int i;
		char *comma = strchr(options, ',');

		if(comma) *comma = 0;

		// Find this option in mount_options
		for(i = 0; i < (sizeof(mount_options) / sizeof(*mount_options)); i++) {
			if(!strcasecmp(mount_options[i].name, options)) {
				long fl = mount_options[i].flags;
				if(fl < 0) *flags &= fl;
				else *flags |= fl;
				break;
			}
		}
		// Unrecognized mount option?
		if(i == (sizeof(mount_options) / sizeof(*mount_options))) {
			// Add it to strflags, to pass on to kernel
			i = *strflags ? strlen(*strflags) : 0;
			*strflags = xrealloc(*strflags, i+strlen(options)+2);
			// Comma separated if it's not the first one
			if(i) (*strflags)[i++] = ',';
			strcpy((*strflags)+i, options);
		}
		// Advance to next option, or finish
		if(comma) {
			*comma = ',';
			options = ++comma;
		} else break;
	}
}

/* This does the work */

extern int mount_main(int argc, char **argv)
{
	char *string_flags = 0, *fsType = 0, *blockDevice = 0, *directory = 0,
		 *loopFile = 0, *buf = 0,
		 *files[] = {"/etc/filesystems", "/proc/filesystems", 0};
	int i, opt, all = FALSE, fakeIt = FALSE, allowWrite = FALSE,
	   	rc = 1, useMtab = ENABLE_FEATURE_MTAB_SUPPORT;
	int flags=0xc0ed0000;	// Needed for linux 2.2, ignored by 2.4 and 2.6.
	FILE *file = 0,*f = 0;
	char path[PATH_MAX*2];
	struct mntent m;
	struct stat statbuf;

	/* parse long options, like --bind and --move.  Note that -o option
	 * and --option are synonymous.  Yes, this means --remount,rw works. */

	for(i = opt = 0; i < argc; i++) {
		if(argv[i][0] == '-' && argv[i][1] == '-')
			parse_mount_options(argv[i]+2, &flags, &string_flags);
		else argv[opt++] = argv[i];
	}
	argc = opt;

	// Parse remaining options

	while((opt = getopt(argc, argv, "o:t:rwafnv")) > 0) {
		switch (opt) {
		case 'o':
			parse_mount_options(optarg, &flags, &string_flags);
			break;
		case 't':
			fsType = optarg;
			break;
		case 'r':
			flags |= MS_RDONLY;
			break;
		case 'w':
			allowWrite=TRUE;
			break;
		case 'a':
			all = TRUE;
			break;
		case 'f':
			fakeIt = TRUE;
			break;
		case 'n':
			useMtab = FALSE;
			break;
		case 'v':
			break;		// ignore -v
		default:
			bb_show_usage();
		}
	}

	// If we have no arguments, show currently mounted filesystems

	if(!all && (optind == argc)) {
		FILE *mountTable = setmntent(bb_path_mtab_file, "r");

		if(!mountTable) bb_perror_msg_and_die(bb_path_mtab_file);

		while (getmntent_r(mountTable,&m,path,sizeof(path))) {
			blockDevice = m.mnt_fsname;

			// Clean up display a little bit regarding root devie
			if(!strcmp(blockDevice, "rootfs")) continue;
			if(!strcmp(blockDevice, "/dev/root"))
				blockDevice = find_block_device("/");

			if(!fsType || !strcmp(m.mnt_type, fsType))
				printf("%s on %s type %s (%s)\n", blockDevice, m.mnt_dir,
					   m.mnt_type, m.mnt_opts);
			if(ENABLE_FEATURE_CLEAN_UP && blockDevice != m.mnt_fsname)
				free(blockDevice);
		}
		endmntent(mountTable);
		return EXIT_SUCCESS;
	}

	/* The next argument is what to mount.  if there's an argument after that
	 * it's where to mount it.  If we're not mounting all, and we have both
	 * of these arguments, jump straight to the actual mount. */

	statbuf.st_mode=0;
	if(optind < argc)
		blockDevice = !stat(argv[optind], &statbuf) ?
		  	 	bb_simplify_path(argv[optind]) :
				(ENABLE_FEATURE_CLEAN_UP ? strdup(argv[optind]) : argv[optind]);
	if(optind+1 < argc) directory = bb_simplify_path(argv[optind+1]);

    // If we don't have to loop through fstab, skip ahead a bit.

	if(!all && optind+1!=argc) goto singlemount;

	// Loop through /etc/fstab entries to look up this entry.

	if(!(file=setmntent("/etc/fstab","r")))
		bb_perror_msg_and_die("\nCannot read /etc/fstab");
	for(;;) {

		// Get next fstab entry

		if(!getmntent_r(file,&m,path,sizeof(path))) {
			if(!all)
				bb_perror_msg("Can't find %s in /etc/fstab\n", blockDevice);
			break;
		}
		
		// If we're mounting all and all doesn't mount this one, skip it.

		if(all) {
			if(strstr(m.mnt_opts,"noauto") || strstr(m.mnt_type,"swap"))
				continue;
			flags=0;

		/* If we're mounting something specific and this isn't it, skip it.
		 * Note we must match both the exact text in fstab (ala "proc") or
		 * a full path from root */

		} else if(strcmp(blockDevice,m.mnt_fsname) &&
				  strcmp(argv[optind],m.mnt_fsname) &&
				  strcmp(blockDevice,m.mnt_dir) &&
				  strcmp(argv[optind],m.mnt_dir)) continue;

		/* Parse flags from /etc/fstab (unless this is a single mount
		 * overriding fstab -- note the "all" test above zeroed the flags,
		 * to prevent flags from previous entries affecting this one, so
		 * the only way we could get here with nonzero flags is a single
		 * mount). */

		if(!flags) {
			if(ENABLE_FEATURE_CLEAN_UP) free(string_flags);
			string_flags=NULL;
			parse_mount_options(m.mnt_opts, &flags, &string_flags);
		}

		/* Fill out remaining fields with info from mtab */

		if(ENABLE_FEATURE_CLEAN_UP) {
			free(blockDevice);
			blockDevice=strdup(m.mnt_fsname);
			free(directory);
			directory=strdup(m.mnt_type);
		} else {
			blockDevice=m.mnt_fsname;
			directory=m.mnt_dir;
		}
		fsType=m.mnt_type;

		/* Ok, we're ready to actually mount a specific source on a specific
		 * directory now. */

singlemount:

		// If they said -w, override fstab

		if(allowWrite) flags&=~MS_RDONLY;

		// Might this be an NFS filesystem?

		if(ENABLE_FEATURE_MOUNT_NFS && (!fsType || !strcmp(fsType,"nfs")) &&
			strchr(blockDevice, ':') != NULL)
		{
			if(nfsmount(blockDevice, directory, &flags, &string_flags, 1))
				bb_perror_msg("nfsmount failed");
			else {
				rc = 0;
				fsType="nfs";
				// Strangely enough, nfsmount() doesn't actually mount()
				goto mount_it_now;
			}
		} else {
			
			// Do we need to allocate a loopback device?

			if(ENABLE_FEATURE_MOUNT_LOOP && !fakeIt && S_ISREG(statbuf.st_mode))
			{
				loopFile = blockDevice;
				blockDevice = 0;
				switch(set_loop(&blockDevice, loopFile, 0)) {
					case 0:
					case 1:
						break;
					default:
						bb_error_msg_and_die(
							errno == EPERM || errno == EACCES ?
							bb_msg_perm_denied_are_you_root :
							"Couldn't setup loop device");
						break;
				}
			}

			/* If we know the fstype (or don't need to), jump straight
			 * to the actual mount. */

			if(fsType || (flags & (MS_REMOUNT | MS_BIND | MS_MOVE)))
				goto mount_it_now;
		}
		
		// Loop through filesystem types until mount succeeds or we run out

		for(i = 0; files[i] && rc; i++) {
			f = fopen(files[i], "r");
			if(!f) continue;
			// Get next block device backed filesystem
			for(buf = 0; (buf = fsType = bb_get_chomped_line_from_file(f));
				   	free(buf))
			{
				// Skip funky entries in /proc
				if(!strncmp(buf,"nodev",5) && isspace(buf[5])) continue;
				
				while(isspace(*fsType)) fsType++;
				if(*buf=='#' || *buf=='*') continue;
				if(!*fsType) continue;
mount_it_now:
				// Okay, try to mount

				if (!fakeIt) {
					for(;;) {
						rc = mount(blockDevice, directory, fsType, flags, string_flags);
						if(!rc || (flags&MS_RDONLY) || (errno!=EACCES && errno!=EROFS))
							break;
						bb_error_msg("%s is write-protected, mounting read-only", blockDevice);
						flags|=MS_RDONLY;
					}
				}
				if(!rc || !f) break;
			}
			if(f) fclose(f);
			if(!f || !rc) break;
		}

		/* If the mount was successful, and we're maintaining an old-style
		 * mtab file by hand, add new entry to it now. */
		if((!rc || fakeIt) && useMtab) {
			FILE *mountTable = setmntent(bb_path_mtab_file, "a+");

			if(!mountTable) bb_perror_msg(bb_path_mtab_file);
			else {
				// Remove trailing / (if any) from directory we mounted on
				int length=strlen(directory);
				if(length>1 && directory[length-1] == '/')
					directory[length-1]=0;

				// Fill out structure (should be ok to re-use existing one).
				m.mnt_fsname=blockDevice;
				m.mnt_dir=directory;
				m.mnt_type=fsType ? : "--bind";
				m.mnt_opts=string_flags ? :
					((flags & MS_RDONLY) ? "ro" : "rw");
				m.mnt_freq = 0;
				m.mnt_passno = 0;

				// Write and close
				addmntent(mountTable, &m);
				endmntent(mountTable);
			}
		} else {
			// Mount failed.  Clean up
			if(loopFile) {
				del_loop(blockDevice);
				if(ENABLE_FEATURE_CLEAN_UP) free(loopFile);
			}
			// Don't whine about already mounted fs when mounting all.
			if(rc<0 && errno == EBUSY && all) rc = 0;
			else if (errno == EPERM)
				bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
		}
		// We couldn't free this earlier becase fsType could be in buf.
		if(ENABLE_FEATURE_CLEAN_UP) {
			free(buf);
			free(blockDevice);
			free(directory);
		}
		if(!all) break;
	}

	if(file) endmntent(file);
	if(rc) bb_perror_msg("Mounting %s on %s failed", blockDevice, directory);

	return rc;
}