static struct mntentchn *find_rw_mount(const char *device)
{
struct mntentchn *mc;
char *fsname = canonicalize(device);
mc = getmntdevbackward(fsname, NULL);
while (mc) {
if (strcmp(mc->m.mnt_type, fstype) == 0 &&
find_opt(mc->m.mnt_opts, "rw", NULL) >= 0)
break;
mc = getmntdevbackward(fsname, mc);
}
my_free(fsname);
return mc;
}
/*
* umount_one_bw: unmount FILE that has last occurrence MC0
*
* Why this loop?
* 1. People who boot a system with a bad fstab root entry
* will get an incorrect "/dev/foo on /" in mtab.
* If later /dev/foo is actually mounted elsewhere,
* it will occur twice in mtab.
* 2. With overmounting one can get the situation that
* the same filename is used as mount point twice.
* In both cases, it is best to try the last occurrence first.
*/
static int
umount_one_bw (const char *file, struct mntentchn *mc0) {
struct mntentchn *mc;
int res = 1;
mc = mc0;
while (res && mc) {
res = umount_one(mc->m.mnt_fsname, mc->m.mnt_dir,
mc->m.mnt_type, mc->m.mnt_opts, mc);
mc = getmntdirbackward(file, mc);
}
mc = mc0;
while (res && mc) {
res = umount_one(mc->m.mnt_fsname, mc->m.mnt_dir,
mc->m.mnt_type, mc->m.mnt_opts, mc);
mc = getmntdevbackward(file, mc);
}
return res;
}
static int
umount_file (char *arg) {
struct mntentchn *mc, *fs;
const char *file, *options;
int fstab_has_user, fstab_has_users, fstab_has_owner, fstab_has_group;
int ok;
if (!*arg) { /* "" would be expanded to `pwd` */
die(2, _("Cannot umount \"\"\n"));
return 0;
}
file = canonicalize(arg); /* mtab paths are canonicalized */
if (verbose > 1)
printf(_("Trying to umount %s\n"), file);
mc = getmntdirbackward(file, NULL);
if (!mc) {
mc = getmntdevbackward(file, NULL);
if (mc) {
struct mntentchn *mc1;
mc1 = getmntdirbackward(mc->m.mnt_dir, NULL);
if (!mc1)
/* 'mc1' must exist, though not necessarily
equals to `mc'. Otherwise we go mad. */
die(EX_SOFTWARE,
_("umount: confused when analyzing mtab"));
if (strcmp(file, mc1->m.mnt_fsname)) {
/* Something was stacked over `file' on the
same mount point. */
die(EX_FAIL, _("umount: cannot umount %s -- %s is "
"mounted over it on the same point."),
file, mc1->m.mnt_fsname);
}
}
}
if (!mc && verbose)
printf(_("Could not find %s in mtab\n"), file);
if (restricted) {
char *mtab_user = NULL;
if (!mc)
die(2,
_("umount: %s is not mounted (according to mtab)"),
file);
/*
* uhelper - unprivileged umount helper
* -- external umount (for example HAL mounts)
*/
if (external_allowed) {
char *uhelper = NULL;
if (mc->m.mnt_opts)
uhelper = get_value(mc->m.mnt_opts, "uhelper=");
if (uhelper) {
int status = 0;
if (check_special_umountprog(arg, arg,
uhelper, &status))
return status;
}
}
/* The 2.4 kernel will generally refuse to mount the same
filesystem on the same mount point, but will accept NFS.
So, unmounting must be possible. */
if (!is_mounted_once(file) && strcmp(mc->m.mnt_type,"nfs"))
die(2,
_("umount: it seems %s is mounted multiple times"),
file);
/* If fstab contains the two lines
/dev/sda1 /mnt/zip auto user,noauto 0 0
/dev/sda4 /mnt/zip auto user,noauto 0 0
then "mount /dev/sda4" followed by "umount /mnt/zip"
used to fail. So, we must not look for file, but for
the pair (dev,file) in fstab. */
fs = getfs_by_devdir(mc->m.mnt_fsname, mc->m.mnt_dir);
if (!fs) {
fs = getfs_by_dir(file);
if (!fs && !getfs_by_spec(file))
die (2,
_("umount: %s is not in the fstab "
"(and you are not root)"),
file);
/* spec could be a file which is loop mounted */
if (fs && !is_valid_loop(mc, fs))
die (2, _("umount: %s mount disagrees with "
"the fstab"), file);
}
/*
* User mounting and unmounting is allowed only
* if fstab contains one of the options `user',
* `users' or `owner' or `group'.
*
* The option `users' allows arbitrary users to mount
* and unmount - this may be a security risk.
*
* The options `user', `owner' and `group' only allow
* unmounting by the user that mounted (visible in mtab).
*/
options = fs->m.mnt_opts;
if (!options)
options = "";
fstab_has_user = contains(options, "user");
fstab_has_users = contains(options, "users");
fstab_has_owner = contains(options, "owner");
fstab_has_group = contains(options, "group");
ok = 0;
if (fstab_has_users)
ok = 1;
if (!ok && (fstab_has_user || fstab_has_owner ||
fstab_has_group)) {
char *user = getusername();
options = mc->m.mnt_opts;
if (!options)
options = "";
mtab_user = get_value(options, "user="******"umount: only %s can unmount %s from %s"),
mtab_user ? mtab_user : "******",
fs->m.mnt_fsname, fs->m.mnt_dir);
}
if (mc)
return umount_one_bw (file, mc);
else
return umount_one (arg, arg, arg, arg, NULL);
}
