1 /* mount.c - mount filesystems
2 *
3 * Copyright 2014 Rob Landley <rob@landley.net>
4 *
5 * See http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/mount.html
6 *
7 * Note: -hV is bad spec, haven't implemented -FsLU yet
8 * no mtab (/proc/mounts does it) so -n is NOP.
9 * TODO mount -o loop,autoclear (linux git 96c5865559ce)
10 * TODO mount jffs2.img dir (block2mtd)
11 * TODO fstab user
12 * TODO mount [^/]*:def = nfs, \\samba
13
14 USE_MOUNT(NEWTOY(mount, "?RO:afnrvwt:o*[-rw]", TOYFLAG_BIN|TOYFLAG_STAYROOT))
15 //USE_NFSMOUNT(NEWTOY(nfsmount, "<2>2", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_STAYROOT))
16
17 config MOUNT
18 bool "mount"
19 default y
20 help
21 usage: mount [-afFrsvw] [-t TYPE] [-o OPTION,] [[DEVICE] DIR]
22
23 Mount new filesystem(s) on directories. With no arguments, display existing
24 mounts.
25
26 -a Mount all entries in /etc/fstab (with -t, only entries of that TYPE)
27 -O Only mount -a entries that have this option
28 -f Fake it (don't actually mount)
29 -r Read only (same as -o ro)
30 -w Read/write (default, same as -o rw)
31 -t Specify filesystem type
32 -v Verbose
33
34 OPTIONS is a comma separated list of options, which can also be supplied
35 as --longopts.
36
37 Autodetects loopback mounts (a file on a directory) and bind mounts (file
38 on file, directory on directory), so you don't need to say --bind or --loop.
39 You can also "mount -a /path" to mount everything in /etc/fstab under /path,
40 even if it's noauto. DEVICE starting with UUID= is identified by blkid -U.
41
42 #config SMBMOUNT
43 # bool "smbmount"
44 # default n
45 # helo
46 # usage: smbmount SHARE DIR
47 #
48 # Mount smb share with user/pasword prompt as necessary.
49 #
50 #config NFSMOUNT
51 # bool "nfsmount"
52 # default n
53 # help
54 # usage: nfsmount SHARE DIR
55 #
56 # Invoke an eldrich horror from the dawn of time.
57 */
58
59 #define FOR_mount
60 #include "toys.h"
61
62 GLOBALS(
63 struct arg_list *o;
64 char *t, *O;
65
66 unsigned long flags;
67 char *opts;
68 int okuser;
69 )
70
71 // mount.tests should check for all of this:
72 // TODO detect existing identical mount (procfs with different dev name?)
73 // TODO user, users, owner, group, nofail
74 // TODO -p (passfd)
75 // TODO -a -t notype,type2
76 // TODO --subtree
77 // TODO make "mount --bind,ro old new" work (implicit -o remount)
78 // TODO mount -a
79 // TODO mount -o remount
80 // TODO fstab: lookup default options for mount
81 // TODO implement -v
82 // TODO "mount -a -o remount,ro" should detect overmounts
83 // TODO work out how that differs from "mount -ar"
84 // TODO what if you --bind mount a block device somewhere (file, dir, dev)
85 // TODO "touch servername; mount -t cifs servername path"
86 // TODO mount -o remount a user mount
87 // TODO mount image.img sub (auto-loopback) then umount image.img
88 // TODO mount UUID=blah
89
90 // Strip flags out of comma separated list of options, return flags,.
91 // TODO: flip order and it's tagged array?
flag_opts(char * new,long flags,char ** more)92 static long flag_opts(char *new, long flags, char **more)
93 {
94 struct {
95 char *name;
96 long flags;
97 } opts[] = {
98 {"loop", 0}, {"defaults", 0}, {"quiet", 0}, // NOPs
99 {"user", 0}, {"nouser", 0}, // checked in fstab, ignored in -o
100 {"bind", MS_REC}, {"rbind", ~MS_REC}, // Autodetected but override defaults
101 {"ro", MS_RDONLY}, {"rw", ~MS_RDONLY},
102 {"nosuid", MS_NOSUID}, {"suid", ~MS_NOSUID},
103 {"nodev", MS_NODEV}, {"dev", ~MS_NODEV},
104 {"noexec", MS_NOEXEC}, {"exec", ~MS_NOEXEC},
105 {"sync", MS_SYNCHRONOUS}, {"async", ~MS_SYNCHRONOUS},
106 {"noatime", MS_NOATIME}, {"atime", ~MS_NOATIME},
107 {"norelatime", ~MS_RELATIME}, {"relatime", MS_RELATIME},
108 {"nodiratime", MS_NODIRATIME}, {"diratime", ~MS_NODIRATIME},
109 {"loud", ~MS_SILENT},
110 {"shared", MS_SHARED}, {"rshared", MS_SHARED|MS_REC},
111 {"slave", MS_SLAVE}, {"rslave", MS_SLAVE|MS_REC},
112 {"private", MS_PRIVATE}, {"rprivate", MS_SLAVE|MS_REC},
113 {"unbindable", MS_UNBINDABLE}, {"runbindable", MS_UNBINDABLE|MS_REC},
114 {"remount", MS_REMOUNT}, {"move", MS_MOVE},
115 // mand dirsync rec iversion strictatime
116 };
117
118 if (new) for (;;) {
119 char *comma = strchr(new, ',');
120 int i;
121
122 if (comma) *comma = 0;
123
124 // If we recognize an option, apply flags
125 for (i = 0; i < ARRAY_LEN(opts); i++) if (!strcasecmp(opts[i].name, new)) {
126 long ll = opts[i].flags;
127
128 if (ll < 0) flags &= ll;
129 else flags |= ll;
130
131 break;
132 }
133
134 // If we didn't recognize it, keep string version
135 if (more && i == ARRAY_LEN(opts)) {
136 i = *more ? strlen(*more) : 0;
137 *more = xrealloc(*more, i + strlen(new) + 2);
138 if (i) (*more)[i++] = ',';
139 strcpy(i+*more, new);
140 }
141
142 if (!comma) break;
143 *comma = ',';
144 new = comma + 1;
145 }
146
147 return flags;
148 }
149
mount_filesystem(char * dev,char * dir,char * type,unsigned long flags,char * opts)150 static void mount_filesystem(char *dev, char *dir, char *type,
151 unsigned long flags, char *opts)
152 {
153 FILE *fp = 0;
154 int rc = EINVAL;
155 char *buf = 0;
156
157 if (FLAG(f)) return;
158
159 if (getuid()) {
160 if (TT.okuser) TT.okuser = 0;
161 else {
162 error_msg("'%s' not user mountable in fstab", dev);
163
164 return;
165 }
166 }
167
168 if (strstart(&dev, "UUID=")) {
169 char *s = chomp(xrunread((char *[]){"blkid", "-U", dev, 0}, 0));
170
171 if (!s || strlen(s)>=sizeof(toybuf)) return error_msg("No uuid %s", dev);
172 strcpy(dev = toybuf, s);
173 free(s);
174 }
175
176 // Autodetect bind mount or filesystem type
177
178 if (type && (!strcmp(type, "auto") || !strcmp(type, "none"))) type = 0;
179 if (flags & MS_MOVE) {
180 if (type) error_exit("--move with -t");
181 } else if (!type) {
182 struct stat stdev, stdir;
183
184 // file on file or dir on dir is a --bind mount.
185 if (!stat(dev, &stdev) && !stat(dir, &stdir)
186 && ((S_ISREG(stdev.st_mode) && S_ISREG(stdir.st_mode))
187 || (S_ISDIR(stdev.st_mode) && S_ISDIR(stdir.st_mode))))
188 {
189 flags ^= MS_REC;
190 flags |= MS_BIND;
191 } else fp = xfopen("/proc/filesystems", "r");
192 } else if (!strcmp(type, "ignore")) return;
193 else if (!strcmp(type, "swap"))
194 toys.exitval |= xrun((char *[]){"swapon", "--", dev, 0});
195
196 for (;;) {
197 int fd = -1, ro = 0;
198
199 // If type wasn't specified, try all of them in order.
200 if (fp && !buf) {
201 size_t i;
202
203 if (getline(&buf, &i, fp)<1) {
204 error_msg("%s: need -t", dev);
205 break;
206 }
207 type = buf;
208 // skip nodev devices
209 if (!isspace(*type)) {
210 free(buf);
211 buf = 0;
212
213 continue;
214 }
215 // trim whitespace
216 while (isspace(*type)) type++;
217 i = strlen(type);
218 if (i) type[i-1] = 0;
219 }
220 if (FLAG(v)) printf("try '%s' type '%s' on '%s'\n", dev, type, dir);
221 for (;;) {
222 rc = mount(dev, dir, type, flags, opts);
223 // Did we succeed, fail unrecoverably, or already try read-only?
224 if (!rc || (errno != EACCES && errno != EROFS) || (flags&MS_RDONLY))
225 break;
226 // If we haven't already tried it, use the BLKROSET ioctl to ensure
227 // that the underlying device isn't read-only.
228 if (fd == -1) {
229 if (FLAG(v))
230 printf("trying BLKROSET ioctl on '%s'\n", dev);
231 if (-1 != (fd = open(dev, O_RDONLY))) {
232 rc = ioctl(fd, BLKROSET, &ro);
233 close(fd);
234 if (!rc) continue;
235 }
236 }
237 fprintf(stderr, "'%s' is read-only\n", dev);
238 flags |= MS_RDONLY;
239 }
240
241 // Trying to autodetect loop mounts like bind mounts above (file on dir)
242 // isn't good enough because "mount -t ext2 fs.img dir" is valid, but if
243 // you _do_ accept loop mounts with -t how do you tell "-t cifs" isn't
244 // looking for a block device if it's not in /proc/filesystems yet
245 // because the fs module won't be loaded until you try the mount, and
246 // if you can't then DEVICE existing as a file would cause a false
247 // positive loopback mount (so "touch servername" becomes a potential
248 // denial of service attack...)
249 //
250 // Solution: try the mount, let the kernel tell us it wanted a block
251 // device, then do the loopback setup and retry the mount.
252
253 if (rc && errno == ENOTBLK) {
254 char *losetup[] = {"losetup", (flags&MS_RDONLY)?"-fsr":"-fs", dev, 0};
255
256 if ((dev = chomp(xrunread(losetup, 0)))) continue;
257 error_msg("%s failed", *losetup);
258 break;
259 }
260
261 free(buf);
262 buf = 0;
263 if (!rc) break;
264 if (fp && (errno == EINVAL || errno == EBUSY)) continue;
265
266 perror_msg("'%s'->'%s'", dev, dir);
267
268 break;
269 }
270 if (fp) fclose(fp);
271 }
272
mount_main(void)273 void mount_main(void)
274 {
275 char *opts = 0, *dev = 0, *dir = 0, **ss;
276 long flags = MS_SILENT;
277 struct arg_list *o;
278 struct mtab_list *mtl, *mtl2 = 0, *mm, *remount;
279
280 // TODO
281 // remount
282 // - overmounts
283 // shared subtree
284 // -o parsed after fstab options
285 // test if mountpoint already exists (-o noremount?)
286
287 // First pass; just accumulate string, don't parse flags yet. (This is so
288 // we can modify fstab entries with -a, or mtab with remount.)
289 for (o = TT.o; o; o = o->next) comma_collate(&opts, o->arg);
290 if (FLAG(r)) comma_collate(&opts, "ro");
291 if (FLAG(w)) comma_collate(&opts, "rw");
292 if (FLAG(R)) comma_collate(&opts, "rbind");
293
294 // Treat each --option as -o option
295 for (ss = toys.optargs; *ss; ss++) {
296 char *sss = *ss;
297
298 // If you realy, really want to mount a file named "--", we support it.
299 if (sss[0]=='-' && sss[1]=='-' && sss[2]) comma_collate(&opts, sss+2);
300 else if (!dev) dev = sss;
301 else if (!dir) dir = sss;
302 // same message as lib/args.c ">2" which we can't use because --opts count
303 else error_exit("Max 2 arguments\n");
304 }
305
306 if (FLAG(a) && dir) error_exit("-a with >1 arg");
307
308 // For remount we need _last_ match (in case of overmounts), so traverse
309 // in reverse order. (Yes I'm using remount as a boolean for a bit here,
310 // the double cast is to get gcc to shut up about it.)
311 remount = (void *)(long)comma_scan(opts, "remount", 0);
312 if ((FLAG(a) && !access("/proc/mounts", R_OK)) || remount) {
313 mm = dlist_terminate(mtl = mtl2 = xgetmountlist(0));
314 if (remount) remount = mm;
315 }
316
317 // Do we need to do an /etc/fstab trawl?
318 // This covers -a, -o remount, one argument, all user mounts
319 if (FLAG(a) || (dev && (!dir || getuid() || remount))) {
320 if (!remount) dlist_terminate(mtl = xgetmountlist("/etc/fstab"));
321
322 for (mm = remount ? remount : mtl; mm; mm = (remount ? mm->prev : mm->next))
323 {
324 char *aopts = 0;
325 struct mtab_list *mmm = 0;
326 int aflags, noauto, len;
327
328 // Check for noauto and get it out of the option list. (Unknown options
329 // that make it to the kernel give filesystem drivers indigestion.)
330 noauto = comma_scan(mm->opts, "noauto", 1);
331
332 if (FLAG(a)) {
333 // "mount -a /path" to mount all entries under /path
334 if (dev) {
335 len = strlen(dev);
336 if (strncmp(dev, mm->dir, len)
337 || (mm->dir[len] && mm->dir[len] != '/')) continue;
338 } else if (noauto) continue; // never present in the remount case
339 if (!mountlist_istype(mm, TT.t) || !comma_scanall(mm->opts, TT.O))
340 continue;
341 } else {
342 if (dir && strcmp(dir, mm->dir)) continue;
343 if (strcmp(dev, mm->device) && (dir || strcmp(dev, mm->dir))) continue;
344 }
345
346 // Don't overmount the same dev on the same directory
347 // (Unless root explicitly says to in non -a mode.)
348 if (mtl2 && !remount)
349 for (mmm = mtl2; mmm; mmm = mmm->next)
350 if (!strcmp(mm->dir, mmm->dir) && !strcmp(mm->device, mmm->device))
351 break;
352
353 // user only counts from fstab, not opts.
354 if (!mmm) {
355 TT.okuser = comma_scan(mm->opts, "user", 1);
356 aflags = flag_opts(mm->opts, flags, &aopts);
357 aflags = flag_opts(opts, aflags, &aopts);
358
359 mount_filesystem(mm->device, mm->dir, mm->type, aflags, aopts);
360 } // TODO else if (getuid()) error_msg("already there") ?
361 free(aopts);
362
363 if (!FLAG(a)) break;
364 }
365 if (CFG_TOYBOX_FREE) {
366 llist_traverse(mtl, free);
367 llist_traverse(mtl2, free);
368 }
369 if (!mm && !FLAG(a))
370 error_exit("'%s' not in %s", dir ? dir : dev,
371 remount ? "/proc/mounts" : "fstab");
372
373 // show mounts from /proc/mounts
374 } else if (!dev) {
375 for (mtl = xgetmountlist(0); mtl && (mm = dlist_pop(&mtl)); free(mm)) {
376 char *s = 0;
377
378 if (TT.t && strcmp(TT.t, mm->type)) continue;
379 if (*mm->device == '/') s = xabspath(mm->device, 0);
380 xprintf("%s on %s type %s (%s)\n",
381 s ? s : mm->device, mm->dir, mm->type, mm->opts);
382 free(s);
383 }
384
385 // two arguments
386 } else {
387 char *more = 0;
388
389 flags = flag_opts(opts, flags, &more);
390 mount_filesystem(dev, dir, TT.t, flags, more);
391 if (CFG_TOYBOX_FREE) free(more);
392 }
393 }
394