static int update_add_entry(struct libmnt_update *upd, struct libmnt_lock *lc)
{
struct libmnt_table *tb;
int rc = 0;
assert(upd);
assert(upd->fs);
DBG(UPDATE, mnt_debug_h(upd, "%s: add entry", upd->filename));
if (lc)
rc = mnt_lock_file(lc);
if (rc)
return rc;
tb = __mnt_new_table_from_file(upd->filename,
upd->userspace_only ? MNT_FMT_UTAB : MNT_FMT_MTAB);
if (tb) {
struct libmnt_fs *fs = mnt_copy_fs(NULL, upd->fs);
if (!fs)
rc = -ENOMEM;
else {
mnt_table_add_fs(tb, fs);
rc = update_table(upd, tb);
}
}
if (lc)
mnt_unlock_file(lc);
mnt_free_table(tb);
return rc;
}
static int lookup_umount_fs(struct libmnt_context *cxt)
{
int rc, loopdev = 0;
const char *tgt;
struct libmnt_table *mtab = NULL;
struct libmnt_fs *fs;
struct libmnt_cache *cache = NULL;
char *cn_tgt = NULL;
assert(cxt);
assert(cxt->fs);
DBG(CXT, mnt_debug_h(cxt, "umount: lookup FS"));
tgt = mnt_fs_get_target(cxt->fs);
if (!tgt) {
DBG(CXT, mnt_debug_h(cxt, "umount: undefined target"));
return -EINVAL;
}
/*
* The mtab file maybe huge and on systems with utab we have to merge
* userspace mount options into /proc/self/mountinfo. This all is
* expensive. The mtab filter allows to filter out entries, then
* mtab and utab are very tiny files.
*
* *but*... the filter uses mnt_fs_streq_{target,srcpath} functions
* where LABEL, UUID or symlinks are to canonicalized. It means that
* it's usable only for canonicalized stuff (e.g. kernel mountinfo).
*/
if (!cxt->mtab_writable && *tgt == '/' &&
!mnt_context_is_force(cxt) && !mnt_context_is_lazy(cxt)) {
struct stat st;
if (stat(tgt, &st) == 0 && S_ISDIR(st.st_mode)) {
/* we'll canonicalized /proc/self/mountinfo */
cache = mnt_context_get_cache(cxt);
cn_tgt = mnt_resolve_path(tgt, cache);
if (cn_tgt)
mnt_context_set_tabfilter(cxt, mtab_filter, cn_tgt);
}
}
rc = mnt_context_get_mtab(cxt, &mtab);
if (cn_tgt) {
mnt_context_set_tabfilter(cxt, NULL, NULL);
if (!cache)
free(cn_tgt);
}
if (rc) {
DBG(CXT, mnt_debug_h(cxt, "umount: failed to read mtab"));
return rc;
}
try_loopdev:
fs = mnt_table_find_target(mtab, tgt, MNT_ITER_BACKWARD);
if (!fs && mnt_context_is_swapmatch(cxt)) {
/*
* Maybe the option is source rather than target (sometimes
* people use e.g. "umount /dev/sda1")
*/
fs = mnt_table_find_source(mtab, tgt, MNT_ITER_BACKWARD);
if (fs) {
struct libmnt_fs *fs1 = mnt_table_find_target(mtab,
mnt_fs_get_target(fs),
MNT_ITER_BACKWARD);
if (!fs1) {
DBG(CXT, mnt_debug_h(cxt, "mtab is broken?!?!"));
return -EINVAL;
}
if (fs != fs1) {
/* Something was stacked over `file' on the
* same mount point. */
DBG(CXT, mnt_debug_h(cxt,
"umount: %s: %s is mounted "
"over it on the same point",
tgt, mnt_fs_get_source(fs1)));
return -EINVAL;
}
}
}
if (!fs && !loopdev && mnt_context_is_swapmatch(cxt)) {
/*
* Maybe the option is /path/file.img, try to convert to /dev/loopN
*/
struct stat st;
if (stat(tgt, &st) == 0 && S_ISREG(st.st_mode)) {
char *dev = NULL;
int count = loopdev_count_by_backing_file(tgt, &dev);
if (count == 1) {
DBG(CXT, mnt_debug_h(cxt,
"umount: %s --> %s (retry)", tgt, dev));
mnt_fs_set_source(cxt->fs, tgt);
mnt_fs_set_target(cxt->fs, dev);
free(dev);
tgt = mnt_fs_get_target(cxt->fs);
loopdev = 1; /* to avoid endless loop */
goto try_loopdev;
} else if (count > 1)
DBG(CXT, mnt_debug_h(cxt,
"umount: warning: %s is associated "
"with more than one loopdev", tgt));
}
}
if (!fs) {
DBG(CXT, mnt_debug_h(cxt, "umount: cannot find %s in mtab", tgt));
return 0;
}
if (fs != cxt->fs) {
/* copy from mtab to our FS description
*/
mnt_fs_set_source(cxt->fs, NULL);
mnt_fs_set_target(cxt->fs, NULL);
if (!mnt_copy_fs(cxt->fs, fs)) {
DBG(CXT, mnt_debug_h(cxt, "umount: failed to copy FS"));
return -errno;
}
DBG(CXT, mnt_debug_h(cxt, "umount: mtab applied"));
}
cxt->flags |= MNT_FL_TAB_APPLIED;
return rc;
}
/* this is umount replacement to mnt_context_apply_fstab(), use
* mnt_context_tab_applied() to check result.
*/
static int lookup_umount_fs(struct libmnt_context *cxt)
{
const char *tgt;
struct stat st;
struct libmnt_fs *fs = NULL;
int rc = 0;
assert(cxt);
assert(cxt->fs);
tgt = mnt_fs_get_target(cxt->fs);
if (!tgt) {
DBG(CXT, ul_debugobj(cxt, "umount: undefined target"));
return -EINVAL;
}
/*
* Let's try to avoid mountinfo usage at all to minimize performance
* degradation. Don't forget that kernel has to compose *whole*
* mountinfo about all mountpoints although we look for only one entry.
*
* All we need is fstype and to check if there is no userspace mount
* options for the target (e.g. helper=udisks to call /sbin/umount.udisks).
*
* So, let's use statfs() if possible (it's bad idea for --lazy/--force
* umounts as target is probably unreachable NFS, also for --detach-loop
* as this additionally needs to know the name of the loop device).
*/
if (!mnt_context_is_restricted(cxt)
&& *tgt == '/'
&& !(cxt->flags & MNT_FL_HELPER)
&& !mnt_context_mtab_writable(cxt)
&& !mnt_context_is_force(cxt)
&& !mnt_context_is_lazy(cxt)
&& !mnt_context_is_loopdel(cxt)
&& mnt_stat_mountpoint(tgt, &st) == 0 && S_ISDIR(st.st_mode)
&& !has_utab_entry(cxt, tgt)) {
const char *type = mnt_fs_get_fstype(cxt->fs);
/* !mnt_context_mtab_writable(cxt) && has_utab_entry() verified that there
* is no stuff in utab, so disable all mtab/utab related actions */
mnt_context_disable_mtab(cxt, TRUE);
if (!type) {
struct statfs vfs;
if (statfs(tgt, &vfs) == 0)
type = mnt_statfs_get_fstype(&vfs);
if (type) {
rc = mnt_fs_set_fstype(cxt->fs, type);
if (rc)
return rc;
}
}
if (type) {
DBG(CXT, ul_debugobj(cxt,
"umount: mountinfo unnecessary [type=%s]", type));
return 0;
}
}
rc = mnt_context_find_umount_fs(cxt, tgt, &fs);
if (rc < 0)
return rc;
if (rc == 1 || !fs) {
DBG(CXT, ul_debugobj(cxt, "umount: cannot find '%s' in mtab", tgt));
return 0; /* this is correct! */
}
if (fs != cxt->fs) {
/* copy from mtab to our FS description
*/
mnt_fs_set_source(cxt->fs, NULL);
mnt_fs_set_target(cxt->fs, NULL);
if (!mnt_copy_fs(cxt->fs, fs)) {
DBG(CXT, ul_debugobj(cxt, "umount: failed to copy FS"));
return -errno;
}
DBG(CXT, ul_debugobj(cxt, "umount: mtab applied"));
}
cxt->flags |= MNT_FL_TAB_APPLIED;
return rc;
}
static int lookup_umount_fs(struct libmnt_context *cxt)
{
int rc, loopdev = 0;
const char *tgt;
struct libmnt_table *mtab = NULL;
struct libmnt_fs *fs;
assert(cxt);
assert(cxt->fs);
DBG(CXT, mnt_debug_h(cxt, "umount: lookup FS"));
tgt = mnt_fs_get_target(cxt->fs);
if (!tgt) {
DBG(CXT, mnt_debug_h(cxt, "umount: undefined target"));
return -EINVAL;
}
rc = mnt_context_get_mtab(cxt, &mtab);
if (rc) {
DBG(CXT, mnt_debug_h(cxt, "umount: failed to read mtab"));
return rc;
}
try_loopdev:
fs = mnt_table_find_target(mtab, tgt, MNT_ITER_BACKWARD);
if (!fs) {
/* maybe the option is source rather than target (mountpoint) */
fs = mnt_table_find_source(mtab, tgt, MNT_ITER_BACKWARD);
if (fs) {
struct libmnt_fs *fs1 = mnt_table_find_target(mtab,
mnt_fs_get_target(fs),
MNT_ITER_BACKWARD);
if (!fs1) {
DBG(CXT, mnt_debug_h(cxt, "mtab is broken?!?!"));
return -EINVAL;
}
if (fs != fs1) {
/* Something was stacked over `file' on the
* same mount point. */
DBG(CXT, mnt_debug_h(cxt,
"umount: %s: %s is mounted "
"over it on the same point",
tgt, mnt_fs_get_source(fs1)));
return -EINVAL;
}
}
}
if (!fs && !loopdev) {
/*
* Maybe target is /path/file.img, try to convert to /dev/loopN
*/
struct stat st;
if (stat(tgt, &st) == 0 && S_ISREG(st.st_mode)) {
char *dev = NULL;
int count = loopdev_count_by_backing_file(tgt, &dev);
if (count == 1) {
DBG(CXT, mnt_debug_h(cxt,
"umount: %s --> %s (retry)", tgt, dev));
mnt_fs_set_source(cxt->fs, tgt);
mnt_fs_set_target(cxt->fs, dev);
free(dev);
tgt = mnt_fs_get_target(cxt->fs);
loopdev = 1; /* to avoid endless loop */
goto try_loopdev;
} else if (count > 1)
DBG(CXT, mnt_debug_h(cxt,
"umount: warning: %s is associated "
"with more than one loodev", tgt));
}
}
if (!fs) {
DBG(CXT, mnt_debug_h(cxt, "umount: cannot find %s in mtab", tgt));
return 0;
}
if (fs != cxt->fs) {
/* copy from mtab to our FS description
*/
mnt_fs_set_source(cxt->fs, NULL);
mnt_fs_set_target(cxt->fs, NULL);
if (!mnt_copy_fs(cxt->fs, fs)) {
DBG(CXT, mnt_debug_h(cxt, "umount: failed to copy FS"));
return -errno;
}
DBG(CXT, mnt_debug_h(cxt, "umount: mtab applied"));
}
cxt->flags |= MNT_FL_TAB_APPLIED;
return rc;
}
/*
* Allocates utab entry (upd->fs) for mount/remount. This function should be
* called *before* mount(2) syscall. The @fs is used as a read-only template.
*
* Returns: 0 on success, negative number on error, 1 if utabs update is
* unnecessary.
*/
static int utab_new_entry(struct libmnt_update *upd, struct libmnt_fs *fs,
unsigned long mountflags)
{
int rc = 0;
const char *o = NULL, *a = NULL;
char *u = NULL;
assert(fs);
assert(upd);
assert(upd->fs == NULL);
assert(!(mountflags & MS_MOVE));
DBG(UPDATE, mnt_debug("prepare utab entry"));
o = mnt_fs_get_user_options(fs);
a = mnt_fs_get_attributes(fs);
upd->fs = NULL;
if (o) {
/* remove non-mtab options */
rc = mnt_optstr_get_options(o, &u,
mnt_get_builtin_optmap(MNT_USERSPACE_MAP),
MNT_NOMTAB);
if (rc)
goto err;
}
if (!u && !a) {
DBG(UPDATE, mnt_debug("utab entry unnecessary (no options)"));
return 1;
}
/* allocate the entry */
upd->fs = mnt_copy_fs(NULL, fs);
if (!upd->fs) {
rc = -ENOMEM;
goto err;
}
rc = mnt_fs_set_options(upd->fs, u);
if (rc)
goto err;
rc = mnt_fs_set_attributes(upd->fs, a);
if (rc)
goto err;
if (!(mountflags & MS_REMOUNT)) {
rc = set_fs_root(upd, fs, mountflags);
if (rc)
goto err;
}
free(u);
DBG(UPDATE, mnt_debug("utab entry OK"));
return 0;
err:
free(u);
mnt_free_fs(upd->fs);
upd->fs = NULL;
return rc;
}
