/**
* mnt_context_find_umount_fs:
* @cxt: mount context
* @tgt: mountpoint, device, ...
* @pfs: returns point to filesystem
*
* Returns: 0 on success, <0 on error, 1 if target filesystem not found
*/
int mnt_context_find_umount_fs(struct libmnt_context *cxt,
const char *tgt,
struct libmnt_fs **pfs)
{
int rc;
struct libmnt_table *mtab = NULL;
struct libmnt_fs *fs;
char *loopdev = NULL;
if (pfs)
*pfs = NULL;
if (!cxt || !tgt || !pfs)
return -EINVAL;
DBG(CXT, ul_debugobj(cxt, "umount: lookup FS for '%s'", tgt));
if (!*tgt)
return 1; /* empty string is not an error */
/*
* The mount table may be huge, and on systems with utab we have to merge
* userspace mount options into /proc/self/mountinfo. This all is
* expensive. The tab filter allows to filter out entries, then
* a mount table and utab are very tiny files.
*
* *but*... the filter uses mnt_fs_streq_{target,srcpath} functions
* where LABEL, UUID or symlinks are canonicalized. It means that
* it's usable only for canonicalized stuff (e.g. kernel mountinfo).
*/
if (!mnt_context_mtab_writable(cxt) && *tgt == '/' &&
!mnt_context_is_force(cxt) && !mnt_context_is_lazy(cxt))
rc = mnt_context_get_mtab_for_target(cxt, &mtab, tgt);
else
rc = mnt_context_get_mtab(cxt, &mtab);
if (rc) {
DBG(CXT, ul_debugobj(cxt, "umount: failed to read mtab"));
return rc;
}
if (mnt_table_get_nents(mtab) == 0) {
DBG(CXT, ul_debugobj(cxt, "umount: mtab empty"));
return 1;
}
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, ul_debugobj(cxt, "mtab is broken?!?!"));
rc = -EINVAL;
goto err;
}
if (fs != fs1) {
/* Something was stacked over `file' on the
* same mount point. */
DBG(CXT, ul_debugobj(cxt,
"umount: %s: %s is mounted "
"over it on the same point",
tgt, mnt_fs_get_source(fs1)));
rc = -EINVAL;
goto err;
}
}
}
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 (mnt_stat_mountpoint(tgt, &st) == 0 && S_ISREG(st.st_mode)) {
int count;
struct libmnt_cache *cache = mnt_context_get_cache(cxt);
const char *bf = cache ? mnt_resolve_path(tgt, cache) : tgt;
count = loopdev_count_by_backing_file(bf, &loopdev);
if (count == 1) {
DBG(CXT, ul_debugobj(cxt,
"umount: %s --> %s (retry)", tgt, loopdev));
tgt = loopdev;
goto try_loopdev;
} else if (count > 1)
DBG(CXT, ul_debugobj(cxt,
"umount: warning: %s is associated "
"with more than one loopdev", tgt));
}
}
if (pfs)
*pfs = fs;
free(loopdev);
DBG(CXT, ul_debugobj(cxt, "umount fs: %s", fs ? mnt_fs_get_target(fs) :
"<not found>"));
return fs ? 0 : 1;
err:
free(loopdev);
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;
}
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;
}
