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- /* mount.c - mount filesystems
- *
- * Copyright 2014 Rob Landley <rob@landley.net>
- *
- * See http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/mount.html
- *
- * Note: -hV is bad spec, haven't implemented -FsLU yet
- * no mtab (/proc/mounts does it) so -n is NOP.
- * TODO mount -o loop,autoclear (linux git 96c5865559ce)
- USE_MOUNT(NEWTOY(mount, "?O:afnrvwt:o*[-rw]", TOYFLAG_BIN|TOYFLAG_STAYROOT))
- //USE_NFSMOUNT(NEWTOY(nfsmount, "?<2>2", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_STAYROOT))
- config MOUNT
- bool "mount"
- default y
- help
- usage: mount [-afFrsvw] [-t TYPE] [-o OPTION,] [[DEVICE] DIR]
- Mount new filesystem(s) on directories. With no arguments, display existing
- mounts.
- -a Mount all entries in /etc/fstab (with -t, only entries of that TYPE)
- -O Only mount -a entries that have this option
- -f Fake it (don't actually mount)
- -r Read only (same as -o ro)
- -w Read/write (default, same as -o rw)
- -t Specify filesystem type
- -v Verbose
- OPTIONS is a comma separated list of options, which can also be supplied
- as --longopts.
- Autodetects loopback mounts (a file on a directory) and bind mounts (file
- on file, directory on directory), so you don't need to say --bind or --loop.
- You can also "mount -a /path" to mount everything in /etc/fstab under /path,
- even if it's noauto. DEVICE starting with UUID= is identified by blkid -U.
- #config SMBMOUNT
- # bool "smbmount"
- # default n
- # helo
- # usage: smbmount SHARE DIR
- #
- # Mount smb share with user/pasword prompt as necessary.
- #
- #config NFSMOUNT
- # bool "nfsmount"
- # default n
- # help
- # usage: nfsmount SHARE DIR
- #
- # Invoke an eldrich horror from the dawn of time.
- */
- #define FOR_mount
- #include "toys.h"
- GLOBALS(
- struct arg_list *optlist;
- char *type;
- char *bigO;
- unsigned long flags;
- char *opts;
- int okuser;
- )
- // mount.tests should check for all of this:
- // TODO detect existing identical mount (procfs with different dev name?)
- // TODO user, users, owner, group, nofail
- // TODO -p (passfd)
- // TODO -a -t notype,type2
- // TODO --subtree
- // TODO --rbind, -R
- // TODO make "mount --bind,ro old new" work (implicit -o remount)
- // TODO mount -a
- // TODO mount -o remount
- // TODO fstab: lookup default options for mount
- // TODO implement -v
- // TODO "mount -a -o remount,ro" should detect overmounts
- // TODO work out how that differs from "mount -ar"
- // TODO what if you --bind mount a block device somewhere (file, dir, dev)
- // TODO "touch servername; mount -t cifs servername path"
- // TODO mount -o remount a user mount
- // TODO mount image.img sub (auto-loopback) then umount image.img
- // TODO mount UUID=blah
- // Strip flags out of comma separated list of options, return flags,.
- static long flag_opts(char *new, long flags, char **more)
- {
- struct {
- char *name;
- long flags;
- } opts[] = {
- // NOPs (we autodetect --loop and --bind)
- {"loop", 0}, {"bind", 0}, {"defaults", 0}, {"quiet", 0},
- {"user", 0}, {"nouser", 0}, // checked in fstab, ignored in -o
- {"ro", MS_RDONLY}, {"rw", ~MS_RDONLY},
- {"nosuid", MS_NOSUID}, {"suid", ~MS_NOSUID},
- {"nodev", MS_NODEV}, {"dev", ~MS_NODEV},
- {"noexec", MS_NOEXEC}, {"exec", ~MS_NOEXEC},
- {"sync", MS_SYNCHRONOUS}, {"async", ~MS_SYNCHRONOUS},
- {"noatime", MS_NOATIME}, {"atime", ~MS_NOATIME},
- {"norelatime", ~MS_RELATIME}, {"relatime", MS_RELATIME},
- {"nodiratime", MS_NODIRATIME}, {"diratime", ~MS_NODIRATIME},
- {"loud", ~MS_SILENT},
- {"shared", MS_SHARED}, {"rshared", MS_SHARED|MS_REC},
- {"slave", MS_SLAVE}, {"rslave", MS_SLAVE|MS_REC},
- {"private", MS_PRIVATE}, {"rprivate", MS_SLAVE|MS_REC},
- {"unbindable", MS_UNBINDABLE}, {"runbindable", MS_UNBINDABLE|MS_REC},
- {"remount", MS_REMOUNT}, {"move", MS_MOVE},
- // mand dirsync rec iversion strictatime
- };
- if (new) for (;;) {
- char *comma = strchr(new, ',');
- int i;
- if (comma) *comma = 0;
- // If we recognize an option, apply flags
- for (i = 0; i < ARRAY_LEN(opts); i++) if (!strcasecmp(opts[i].name, new)) {
- long ll = opts[i].flags;
- if (ll < 0) flags &= ll;
- else flags |= ll;
- break;
- }
- // If we didn't recognize it, keep string version
- if (more && i == ARRAY_LEN(opts)) {
- i = *more ? strlen(*more) : 0;
- *more = xrealloc(*more, i + strlen(new) + 2);
- if (i) (*more)[i++] = ',';
- strcpy(i+*more, new);
- }
- if (!comma) break;
- *comma = ',';
- new = comma + 1;
- }
- return flags;
- }
- // Shell out to a program, returning the output string or NULL on error
- static char *tortoise(int loud, char **cmd)
- {
- int rc, pipe, len;
- pid_t pid;
- pid = xpopen(cmd, &pipe, 1);
- len = readall(pipe, toybuf, sizeof(toybuf)-1);
- rc = xpclose(pid, pipe);
- if (!rc && len > 1) {
- if (toybuf[len-1] == '\n') --len;
- toybuf[len] = 0;
- return toybuf;
- }
- if (loud) error_msg("%s failed %d", *cmd, rc);
- return 0;
- }
- static void mount_filesystem(char *dev, char *dir, char *type,
- unsigned long flags, char *opts)
- {
- FILE *fp = 0;
- int rc = EINVAL;
- char *buf = 0;
- if (FLAG(f)) return;
- if (getuid()) {
- if (TT.okuser) TT.okuser = 0;
- else {
- error_msg("'%s' not user mountable in fstab", dev);
- return;
- }
- }
- if (strstart(&dev, "UUID=")) {
- char *s = tortoise(0, (char *[]){"blkid", "-U", dev, 0});
- if (!s) return error_msg("No uuid %s", dev);
- dev = s;
- }
- // Autodetect bind mount or filesystem type
- if (type && !strcmp(type, "auto")) type = 0;
- if (flags & MS_MOVE) {
- if (type) error_exit("--move with -t");
- } else if (!type) {
- struct stat stdev, stdir;
- // file on file or dir on dir is a --bind mount.
- if (!stat(dev, &stdev) && !stat(dir, &stdir)
- && ((S_ISREG(stdev.st_mode) && S_ISREG(stdir.st_mode))
- || (S_ISDIR(stdev.st_mode) && S_ISDIR(stdir.st_mode))))
- {
- flags |= MS_BIND;
- } else fp = xfopen("/proc/filesystems", "r");
- } else if (!strcmp(type, "ignore")) return;
- else if (!strcmp(type, "swap"))
- toys.exitval |= xrun((char *[]){"swapon", "--", dev, 0});
- for (;;) {
- int fd = -1, ro = 0;
- // If type wasn't specified, try all of them in order.
- if (fp && !buf) {
- size_t i;
- if (getline(&buf, &i, fp)<1) {
- error_msg("%s: need -t", dev);
- break;
- }
- type = buf;
- // skip nodev devices
- if (!isspace(*type)) {
- free(buf);
- buf = 0;
- continue;
- }
- // trim whitespace
- while (isspace(*type)) type++;
- i = strlen(type);
- if (i) type[i-1] = 0;
- }
- if (FLAG(v)) printf("try '%s' type '%s' on '%s'\n", dev, type, dir);
- for (;;) {
- rc = mount(dev, dir, type, flags, opts);
- // Did we succeed, fail unrecoverably, or already try read-only?
- if (!rc || (errno != EACCES && errno != EROFS) || (flags&MS_RDONLY))
- break;
- // If we haven't already tried it, use the BLKROSET ioctl to ensure
- // that the underlying device isn't read-only.
- if (fd == -1) {
- if (FLAG(v))
- printf("trying BLKROSET ioctl on '%s'\n", dev);
- if (-1 != (fd = open(dev, O_RDONLY))) {
- rc = ioctl(fd, BLKROSET, &ro);
- close(fd);
- if (!rc) continue;
- }
- }
- fprintf(stderr, "'%s' is read-only\n", dev);
- flags |= MS_RDONLY;
- }
- // Trying to autodetect loop mounts like bind mounts above (file on dir)
- // isn't good enough because "mount -t ext2 fs.img dir" is valid, but if
- // you _do_ accept loop mounts with -t how do you tell "-t cifs" isn't
- // looking for a block device if it's not in /proc/filesystems yet
- // because the fs module won't be loaded until you try the mount, and
- // if you can't then DEVICE existing as a file would cause a false
- // positive loopback mount (so "touch servername" becomes a potential
- // denial of service attack...)
- //
- // Solution: try the mount, let the kernel tell us it wanted a block
- // device, then do the loopback setup and retry the mount.
- if (rc && errno == ENOTBLK) {
- dev = tortoise(1, (char *[]){"losetup",
- (flags&MS_RDONLY) ? "-fsr" : "-fs", dev, 0});
- if (!dev) break;
- continue;
- }
- free(buf);
- buf = 0;
- if (!rc) break;
- if (fp && (errno == EINVAL || errno == EBUSY)) continue;
- perror_msg("'%s'->'%s'", dev, dir);
- break;
- }
- if (fp) fclose(fp);
- }
- void mount_main(void)
- {
- char *opts = 0, *dev = 0, *dir = 0, **ss;
- long flags = MS_SILENT;
- struct arg_list *o;
- struct mtab_list *mtl, *mtl2 = 0, *mm, *remount;
- // TODO
- // remount
- // - overmounts
- // shared subtree
- // -o parsed after fstab options
- // test if mountpoint already exists (-o noremount?)
- // First pass; just accumulate string, don't parse flags yet. (This is so
- // we can modify fstab entries with -a, or mtab with remount.)
- for (o = TT.optlist; o; o = o->next) comma_collate(&opts, o->arg);
- if (FLAG(r)) comma_collate(&opts, "ro");
- if (FLAG(w)) comma_collate(&opts, "rw");
- // Treat each --option as -o option
- for (ss = toys.optargs; *ss; ss++) {
- char *sss = *ss;
- // If you realy, really want to mount a file named "--", we support it.
- if (sss[0]=='-' && sss[1]=='-' && sss[2]) comma_collate(&opts, sss+2);
- else if (!dev) dev = sss;
- else if (!dir) dir = sss;
- // same message as lib/args.c ">2" which we can't use because --opts count
- else error_exit("Max 2 arguments\n");
- }
- if (FLAG(a) && dir) error_exit("-a with >1 arg");
- // For remount we need _last_ match (in case of overmounts), so traverse
- // in reverse order. (Yes I'm using remount as a boolean for a bit here,
- // the double cast is to get gcc to shut up about it.)
- remount = (void *)(long)comma_scan(opts, "remount", 0);
- if ((FLAG(a) && !access("/proc/mounts", R_OK)) || remount) {
- mm = dlist_terminate(mtl = mtl2 = xgetmountlist(0));
- if (remount) remount = mm;
- }
- // Do we need to do an /etc/fstab trawl?
- // This covers -a, -o remount, one argument, all user mounts
- if (FLAG(a) || (dev && (!dir || getuid() || remount))) {
- if (!remount) dlist_terminate(mtl = xgetmountlist("/etc/fstab"));
- for (mm = remount ? remount : mtl; mm; mm = (remount ? mm->prev : mm->next))
- {
- char *aopts = 0;
- struct mtab_list *mmm = 0;
- int aflags, noauto, len;
- // Check for noauto and get it out of the option list. (Unknown options
- // that make it to the kernel give filesystem drivers indigestion.)
- noauto = comma_scan(mm->opts, "noauto", 1);
- if (FLAG(a)) {
- // "mount -a /path" to mount all entries under /path
- if (dev) {
- len = strlen(dev);
- if (strncmp(dev, mm->dir, len)
- || (mm->dir[len] && mm->dir[len] != '/')) continue;
- } else if (noauto) continue; // never present in the remount case
- if (!mountlist_istype(mm,TT.type) || !comma_scanall(mm->opts,TT.bigO))
- continue;
- } else {
- if (dir && strcmp(dir, mm->dir)) continue;
- if (strcmp(dev, mm->device) && (dir || strcmp(dev, mm->dir))) continue;
- }
- // Don't overmount the same dev on the same directory
- // (Unless root explicitly says to in non -a mode.)
- if (mtl2 && !remount)
- for (mmm = mtl2; mmm; mmm = mmm->next)
- if (!strcmp(mm->dir, mmm->dir) && !strcmp(mm->device, mmm->device))
- break;
-
- // user only counts from fstab, not opts.
- if (!mmm) {
- TT.okuser = comma_scan(mm->opts, "user", 1);
- aflags = flag_opts(mm->opts, flags, &aopts);
- aflags = flag_opts(opts, aflags, &aopts);
- mount_filesystem(mm->device, mm->dir, mm->type, aflags, aopts);
- } // TODO else if (getuid()) error_msg("already there") ?
- free(aopts);
- if (!FLAG(a)) break;
- }
- if (CFG_TOYBOX_FREE) {
- llist_traverse(mtl, free);
- llist_traverse(mtl2, free);
- }
- if (!mm && !FLAG(a))
- error_exit("'%s' not in %s", dir ? dir : dev,
- remount ? "/proc/mounts" : "fstab");
- // show mounts from /proc/mounts
- } else if (!dev) {
- for (mtl = xgetmountlist(0); mtl && (mm = dlist_pop(&mtl)); free(mm)) {
- char *s = 0;
- if (TT.type && strcmp(TT.type, mm->type)) continue;
- if (*mm->device == '/') s = xabspath(mm->device, 0);
- xprintf("%s on %s type %s (%s)\n",
- s ? s : mm->device, mm->dir, mm->type, mm->opts);
- free(s);
- }
- // two arguments
- } else {
- char *more = 0;
- flags = flag_opts(opts, flags, &more);
- mount_filesystem(dev, dir, TT.type, flags, more);
- if (CFG_TOYBOX_FREE) free(more);
- }
- }
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