/*
* Called by mtab parser to filter out entries, nonzero means that
* entry has to be filter out.
*/
static int mtab_filter(struct libmnt_fs *fs, void *data)
{
if (!fs || !data)
return 0;
if (mnt_fs_streq_target(fs, data))
return 0;
if (mnt_fs_streq_srcpath(fs, data))
return 0;
return 1;
}
/*
* This function uses @uf to found corresponding record in @tb, then the record
* from @tb is updated (user specific mount options are added).
*
* Note that @uf must contain only user specific mount options instead of
* VFS options (note that FS options are ignored).
*
* Returns modified filesystem (from @tb) or NULL.
*/
static struct libmnt_fs *mnt_table_merge_user_fs(struct libmnt_table *tb, struct libmnt_fs *uf)
{
struct libmnt_fs *fs;
struct libmnt_iter itr;
const char *optstr, *src, *target, *root, *attrs;
assert(tb);
assert(uf);
if (!tb || !uf)
return NULL;
DBG(TAB, mnt_debug_h(tb, "merging user fs"));
src = mnt_fs_get_srcpath(uf);
target = mnt_fs_get_target(uf);
optstr = mnt_fs_get_user_options(uf);
attrs = mnt_fs_get_attributes(uf);
root = mnt_fs_get_root(uf);
if (!src || !target || !root || (!attrs && !optstr))
return NULL;
mnt_reset_iter(&itr, MNT_ITER_BACKWARD);
while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
const char *r = mnt_fs_get_root(fs);
if (fs->flags & MNT_FS_MERGED)
continue;
if (r && strcmp(r, root) == 0
&& mnt_fs_streq_target(fs, target)
&& mnt_fs_streq_srcpath(fs, src))
break;
}
if (fs) {
DBG(TAB, mnt_debug_h(tb, "found fs -- appending user optstr"));
mnt_fs_append_options(fs, optstr);
mnt_fs_append_attributes(fs, attrs);
mnt_fs_set_bindsrc(fs, mnt_fs_get_bindsrc(uf));
fs->flags |= MNT_FS_MERGED;
DBG(TAB, mnt_debug_h(tb, "found fs:"));
DBG(TAB, mnt_fs_print_debug(fs, stderr));
}
return fs;
}
/**
* mnt_resolve_target:
* @path: "native" path, a potential mount point
* @cache: cache for results or NULL.
*
* Like mnt_resolve_path(), unless @cache is not NULL and
* mnt_cache_set_targets(cache, mtab) was called: if @path is found in the
* cached @mtab and the matching entry was provided by the kernel, assume that
* @path is already canonicalized. By avoiding a call to realpath(2) on
* known mount points, there is a lower risk of stepping on a stale mount
* point, which can result in an application freeze. This is also faster in
* general, as stat(2) on a mount point is slower than on a regular file.
*
* Returns: absolute path or NULL in case of error. The result has to be
* deallocated by free() if @cache is NULL.
*/
char *mnt_resolve_target(const char *path, struct libmnt_cache *cache)
{
char *p = NULL;
/*DBG(CACHE, ul_debugobj(cache, "resolving target %s", path));*/
if (!cache || !cache->mtab)
return mnt_resolve_path(path, cache);
p = (char *) cache_find_path(cache, path);
if (p)
return p;
else {
struct libmnt_iter itr;
struct libmnt_fs *fs = NULL;
mnt_reset_iter(&itr, MNT_ITER_BACKWARD);
while (mnt_table_next_fs(cache->mtab, &itr, &fs) == 0) {
if (!mnt_fs_is_kernel(fs)
|| mnt_fs_is_swaparea(fs)
|| !mnt_fs_streq_target(fs, path))
continue;
p = strdup(path);
if (!p)
return NULL; /* ENOMEM */
if (cache_add_entry(cache, p, p, MNT_CACHE_ISPATH)) {
free(p);
return NULL; /* ENOMEM */
}
break;
}
}
if (!p)
p = canonicalize_path_and_cache(path, cache);
return p;
}
/* Check if there is something important in the utab file. The parsed utab is
* stored in context->utab and deallocated by mnt_free_context().
*
* This function exists to avoid (if possible) /proc/self/mountinfo usage, so
* don't use thigs like mnt_resolve_target(), mnt_context_get_mtab() etc here.
* See lookup_umount_fs() for more details.
*/
static int has_utab_entry(struct libmnt_context *cxt, const char *target)
{
struct libmnt_cache *cache = NULL;
struct libmnt_fs *fs;
struct libmnt_iter itr;
char *cn = NULL;
int rc = 0;
assert(cxt);
if (!cxt->utab) {
const char *path = mnt_get_utab_path();
if (!path || is_file_empty(path))
return 0;
cxt->utab = mnt_new_table();
if (!cxt->utab)
return 0;
cxt->utab->fmt = MNT_FMT_UTAB;
if (mnt_table_parse_file(cxt->utab, path))
return 0;
}
/* paths in utab are canonicalized */
cache = mnt_context_get_cache(cxt);
cn = mnt_resolve_path(target, cache);
mnt_reset_iter(&itr, MNT_ITER_BACKWARD);
while (mnt_table_next_fs(cxt->utab, &itr, &fs) == 0) {
if (mnt_fs_streq_target(fs, cn)) {
rc = 1;
break;
}
}
if (!cache)
free(cn);
return rc;
}
