/* 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"
# deault 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 (!dev) 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)<0) {
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;
}
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 (dev && 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);
}
}