1 /* mount.c - mount filesystems 2 * 3 * Copyright 2014 Rob Landley <rob (at) 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 11 USE_MOUNT(NEWTOY(mount, "?O:afnrvwt:o*[-rw]", TOYFLAG_BIN|TOYFLAG_STAYROOT)) 12 //USE_NFSMOUNT(NEWTOY(nfsmount, "?<2>2", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_STAYROOT)) 13 14 config MOUNT 15 bool "mount" 16 default y 17 help 18 usage: mount [-afFrsvw] [-t TYPE] [-o OPTION,] [[DEVICE] DIR] 19 20 Mount new filesystem(s) on directories. With no arguments, display existing 21 mounts. 22 23 -a Mount all entries in /etc/fstab (with -t, only entries of that TYPE) 24 -O Only mount -a entries that have this option 25 -f Fake it (don't actually mount) 26 -r Read only (same as -o ro) 27 -w Read/write (default, same as -o rw) 28 -t Specify filesystem type 29 -v Verbose 30 31 OPTIONS is a comma separated list of options, which can also be supplied 32 as --longopts. 33 34 Autodetects loopback mounts (a file on a directory) and bind mounts (file 35 on file, directory on directory), so you don't need to say --bind or --loop. 36 You can also "mount -a /path" to mount everything in /etc/fstab under /path, 37 even if it's noauto. DEVICE starting with UUID= is identified by blkid -U. 38 39 #config SMBMOUNT 40 # bool "smbmount" 41 # deault n 42 # helo 43 # usage: smbmount SHARE DIR 44 # 45 # Mount smb share with user/pasword prompt as necessary. 46 # 47 #config NFSMOUNT 48 # bool "nfsmount" 49 # default n 50 # help 51 # usage: nfsmount SHARE DIR 52 # 53 # Invoke an eldrich horror from the dawn of time. 54 */ 55 56 #define FOR_mount 57 #include "toys.h" 58 59 GLOBALS( 60 struct arg_list *optlist; 61 char *type; 62 char *bigO; 63 64 unsigned long flags; 65 char *opts; 66 int okuser; 67 ) 68 69 // mount.tests should check for all of this: 70 // TODO detect existing identical mount (procfs with different dev name?) 71 // TODO user, users, owner, group, nofail 72 // TODO -p (passfd) 73 // TODO -a -t notype,type2 74 // TODO --subtree 75 // TODO --rbind, -R 76 // TODO make "mount --bind,ro old new" work (implicit -o remount) 77 // TODO mount -a 78 // TODO mount -o remount 79 // TODO fstab: lookup default options for mount 80 // TODO implement -v 81 // TODO "mount -a -o remount,ro" should detect overmounts 82 // TODO work out how that differs from "mount -ar" 83 // TODO what if you --bind mount a block device somewhere (file, dir, dev) 84 // TODO "touch servername; mount -t cifs servername path" 85 // TODO mount -o remount a user mount 86 // TODO mount image.img sub (auto-loopback) then umount image.img 87 // TODO mount UUID=blah 88 89 // Strip flags out of comma separated list of options, return flags,. 90 static long flag_opts(char *new, long flags, char **more) 91 { 92 struct { 93 char *name; 94 long flags; 95 } opts[] = { 96 // NOPs (we autodetect --loop and --bind) 97 {"loop", 0}, {"bind", 0}, {"defaults", 0}, {"quiet", 0}, 98 {"user", 0}, {"nouser", 0}, // checked in fstab, ignored in -o 99 {"ro", MS_RDONLY}, {"rw", ~MS_RDONLY}, 100 {"nosuid", MS_NOSUID}, {"suid", ~MS_NOSUID}, 101 {"nodev", MS_NODEV}, {"dev", ~MS_NODEV}, 102 {"noexec", MS_NOEXEC}, {"exec", ~MS_NOEXEC}, 103 {"sync", MS_SYNCHRONOUS}, {"async", ~MS_SYNCHRONOUS}, 104 {"noatime", MS_NOATIME}, {"atime", ~MS_NOATIME}, 105 {"norelatime", ~MS_RELATIME}, {"relatime", MS_RELATIME}, 106 {"nodiratime", MS_NODIRATIME}, {"diratime", ~MS_NODIRATIME}, 107 {"loud", ~MS_SILENT}, 108 {"shared", MS_SHARED}, {"rshared", MS_SHARED|MS_REC}, 109 {"slave", MS_SLAVE}, {"rslave", MS_SLAVE|MS_REC}, 110 {"private", MS_PRIVATE}, {"rprivate", MS_SLAVE|MS_REC}, 111 {"unbindable", MS_UNBINDABLE}, {"runbindable", MS_UNBINDABLE|MS_REC}, 112 {"remount", MS_REMOUNT}, {"move", MS_MOVE}, 113 // mand dirsync rec iversion strictatime 114 }; 115 116 if (new) for (;;) { 117 char *comma = strchr(new, ','); 118 int i; 119 120 if (comma) *comma = 0; 121 122 // If we recognize an option, apply flags 123 for (i = 0; i < ARRAY_LEN(opts); i++) if (!strcasecmp(opts[i].name, new)) { 124 long ll = opts[i].flags; 125 126 if (ll < 0) flags &= ll; 127 else flags |= ll; 128 129 break; 130 } 131 132 // If we didn't recognize it, keep string version 133 if (more && i == ARRAY_LEN(opts)) { 134 i = *more ? strlen(*more) : 0; 135 *more = xrealloc(*more, i + strlen(new) + 2); 136 if (i) (*more)[i++] = ','; 137 strcpy(i+*more, new); 138 } 139 140 if (!comma) break; 141 *comma = ','; 142 new = comma + 1; 143 } 144 145 return flags; 146 } 147 148 // Shell out to a program, returning the output string or NULL on error 149 static char *tortoise(int loud, char **cmd) 150 { 151 int rc, pipe, len; 152 pid_t pid; 153 154 pid = xpopen(cmd, &pipe, 1); 155 len = readall(pipe, toybuf, sizeof(toybuf)-1); 156 rc = xpclose(pid, pipe); 157 if (!rc && len > 1) { 158 if (toybuf[len-1] == '\n') --len; 159 toybuf[len] = 0; 160 return toybuf; 161 } 162 if (loud) error_msg("%s failed %d", *cmd, rc); 163 164 return 0; 165 } 166 167 static void mount_filesystem(char *dev, char *dir, char *type, 168 unsigned long flags, char *opts) 169 { 170 FILE *fp = 0; 171 int rc = EINVAL; 172 char *buf = 0; 173 174 if (FLAG(f)) return; 175 176 if (getuid()) { 177 if (TT.okuser) TT.okuser = 0; 178 else { 179 error_msg("'%s' not user mountable in fstab", dev); 180 181 return; 182 } 183 } 184 185 if (strstart(&dev, "UUID=")) { 186 char *s = tortoise(0, (char *[]){"blkid", "-U", dev, 0}); 187 188 if (!dev) return error_msg("No uuid %s", dev); 189 dev = s; 190 } 191 192 // Autodetect bind mount or filesystem type 193 194 if (type && !strcmp(type, "auto")) type = 0; 195 if (flags & MS_MOVE) { 196 if (type) error_exit("--move with -t"); 197 } else if (!type) { 198 struct stat stdev, stdir; 199 200 // file on file or dir on dir is a --bind mount. 201 if (!stat(dev, &stdev) && !stat(dir, &stdir) 202 && ((S_ISREG(stdev.st_mode) && S_ISREG(stdir.st_mode)) 203 || (S_ISDIR(stdev.st_mode) && S_ISDIR(stdir.st_mode)))) 204 { 205 flags |= MS_BIND; 206 } else fp = xfopen("/proc/filesystems", "r"); 207 } else if (!strcmp(type, "ignore")) return; 208 else if (!strcmp(type, "swap")) 209 toys.exitval |= xrun((char *[]){"swapon", "--", dev, 0}); 210 211 for (;;) { 212 int fd = -1, ro = 0; 213 214 // If type wasn't specified, try all of them in order. 215 if (fp && !buf) { 216 size_t i; 217 218 if (getline(&buf, &i, fp)<0) { 219 error_msg("%s: need -t", dev); 220 break; 221 } 222 type = buf; 223 // skip nodev devices 224 if (!isspace(*type)) { 225 free(buf); 226 buf = 0; 227 228 continue; 229 } 230 // trim whitespace 231 while (isspace(*type)) type++; 232 i = strlen(type); 233 if (i) type[i-1] = 0; 234 } 235 if (FLAG(v)) 236 printf("try '%s' type '%s' on '%s'\n", dev, type, dir); 237 for (;;) { 238 rc = mount(dev, dir, type, flags, opts); 239 // Did we succeed, fail unrecoverably, or already try read-only? 240 if (!rc || (errno != EACCES && errno != EROFS) || (flags&MS_RDONLY)) 241 break; 242 // If we haven't already tried it, use the BLKROSET ioctl to ensure 243 // that the underlying device isn't read-only. 244 if (fd == -1) { 245 if (FLAG(v)) 246 printf("trying BLKROSET ioctl on '%s'\n", dev); 247 if (-1 != (fd = open(dev, O_RDONLY))) { 248 rc = ioctl(fd, BLKROSET, &ro); 249 close(fd); 250 if (!rc) continue; 251 } 252 } 253 fprintf(stderr, "'%s' is read-only\n", dev); 254 flags |= MS_RDONLY; 255 } 256 257 // Trying to autodetect loop mounts like bind mounts above (file on dir) 258 // isn't good enough because "mount -t ext2 fs.img dir" is valid, but if 259 // you _do_ accept loop mounts with -t how do you tell "-t cifs" isn't 260 // looking for a block device if it's not in /proc/filesystems yet 261 // because the fs module won't be loaded until you try the mount, and 262 // if you can't then DEVICE existing as a file would cause a false 263 // positive loopback mount (so "touch servername" becomes a potential 264 // denial of service attack...) 265 // 266 // Solution: try the mount, let the kernel tell us it wanted a block 267 // device, then do the loopback setup and retry the mount. 268 269 if (rc && errno == ENOTBLK) { 270 dev = tortoise(1, (char *[]){"losetup", 271 (flags&MS_RDONLY) ? "-fsr" : "-fs", dev, 0}); 272 if (!dev) break; 273 } 274 275 free(buf); 276 buf = 0; 277 if (!rc) break; 278 if (fp && (errno == EINVAL || errno == EBUSY)) continue; 279 280 perror_msg("'%s'->'%s'", dev, dir); 281 282 break; 283 } 284 if (fp) fclose(fp); 285 } 286 287 void mount_main(void) 288 { 289 char *opts = 0, *dev = 0, *dir = 0, **ss; 290 long flags = MS_SILENT; 291 struct arg_list *o; 292 struct mtab_list *mtl, *mtl2 = 0, *mm, *remount; 293 294 // TODO 295 // remount 296 // - overmounts 297 // shared subtree 298 // -o parsed after fstab options 299 // test if mountpoint already exists (-o noremount?) 300 301 // First pass; just accumulate string, don't parse flags yet. (This is so 302 // we can modify fstab entries with -a, or mtab with remount.) 303 for (o = TT.optlist; o; o = o->next) comma_collate(&opts, o->arg); 304 if (FLAG(r)) comma_collate(&opts, "ro"); 305 if (FLAG(w)) comma_collate(&opts, "rw"); 306 307 // Treat each --option as -o option 308 for (ss = toys.optargs; *ss; ss++) { 309 char *sss = *ss; 310 311 // If you realy, really want to mount a file named "--", we support it. 312 if (sss[0]=='-' && sss[1]=='-' && sss[2]) comma_collate(&opts, sss+2); 313 else if (!dev) dev = sss; 314 else if (!dir) dir = sss; 315 // same message as lib/args.c ">2" which we can't use because --opts count 316 else error_exit("Max 2 arguments\n"); 317 } 318 319 if (FLAG(a) && dir) error_exit("-a with >1 arg"); 320 321 // For remount we need _last_ match (in case of overmounts), so traverse 322 // in reverse order. (Yes I'm using remount as a boolean for a bit here, 323 // the double cast is to get gcc to shut up about it.) 324 remount = (void *)(long)comma_scan(opts, "remount", 0); 325 if ((FLAG(a) && !access("/proc/mounts", R_OK)) || remount) { 326 mm = dlist_terminate(mtl = mtl2 = xgetmountlist(0)); 327 if (remount) remount = mm; 328 } 329 330 // Do we need to do an /etc/fstab trawl? 331 // This covers -a, -o remount, one argument, all user mounts 332 if (FLAG(a) || (dev && (!dir || getuid() || remount))) { 333 if (!remount) dlist_terminate(mtl = xgetmountlist("/etc/fstab")); 334 335 for (mm = remount ? remount : mtl; mm; mm = (remount ? mm->prev : mm->next)) 336 { 337 char *aopts = 0; 338 struct mtab_list *mmm = 0; 339 int aflags, noauto, len; 340 341 // Check for noauto and get it out of the option list. (Unknown options 342 // that make it to the kernel give filesystem drivers indigestion.) 343 noauto = comma_scan(mm->opts, "noauto", 1); 344 345 if (FLAG(a)) { 346 // "mount -a /path" to mount all entries under /path 347 if (dev) { 348 len = strlen(dev); 349 if (strncmp(dev, mm->dir, len) 350 || (mm->dir[len] && mm->dir[len] != '/')) continue; 351 } else if (noauto) continue; // never present in the remount case 352 if (!mountlist_istype(mm,TT.type) || !comma_scanall(mm->opts,TT.bigO)) 353 continue; 354 } else { 355 if (dir && strcmp(dir, mm->dir)) continue; 356 if (dev && strcmp(dev, mm->device) && (dir || strcmp(dev, mm->dir))) 357 continue; 358 } 359 360 // Don't overmount the same dev on the same directory 361 // (Unless root explicitly says to in non -a mode.) 362 if (mtl2 && !remount) 363 for (mmm = mtl2; mmm; mmm = mmm->next) 364 if (!strcmp(mm->dir, mmm->dir) && !strcmp(mm->device, mmm->device)) 365 break; 366 367 // user only counts from fstab, not opts. 368 if (!mmm) { 369 TT.okuser = comma_scan(mm->opts, "user", 1); 370 aflags = flag_opts(mm->opts, flags, &aopts); 371 aflags = flag_opts(opts, aflags, &aopts); 372 373 mount_filesystem(mm->device, mm->dir, mm->type, aflags, aopts); 374 } // TODO else if (getuid()) error_msg("already there") ? 375 free(aopts); 376 377 if (!FLAG(a)) break; 378 } 379 if (CFG_TOYBOX_FREE) { 380 llist_traverse(mtl, free); 381 llist_traverse(mtl2, free); 382 } 383 if (!mm && !FLAG(a)) 384 error_exit("'%s' not in %s", dir ? dir : dev, 385 remount ? "/proc/mounts" : "fstab"); 386 387 // show mounts from /proc/mounts 388 } else if (!dev) { 389 for (mtl = xgetmountlist(0); mtl && (mm = dlist_pop(&mtl)); free(mm)) { 390 char *s = 0; 391 392 if (TT.type && strcmp(TT.type, mm->type)) continue; 393 if (*mm->device == '/') s = xabspath(mm->device, 0); 394 xprintf("%s on %s type %s (%s)\n", 395 s ? s : mm->device, mm->dir, mm->type, mm->opts); 396 free(s); 397 } 398 399 // two arguments 400 } else { 401 char *more = 0; 402 403 flags = flag_opts(opts, flags, &more); 404 mount_filesystem(dev, dir, TT.type, flags, more); 405 if (CFG_TOYBOX_FREE) free(more); 406 } 407 } 408
